1 //===--- SemaChecking.cpp - Extra Semantic Checking -----------------------===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // This file implements extra semantic analysis beyond what is enforced 11 // by the C type system. 12 // 13 //===----------------------------------------------------------------------===// 14 15 #include "clang/Sema/SemaInternal.h" 16 #include "clang/AST/ASTContext.h" 17 #include "clang/AST/CharUnits.h" 18 #include "clang/AST/DeclCXX.h" 19 #include "clang/AST/DeclObjC.h" 20 #include "clang/AST/EvaluatedExprVisitor.h" 21 #include "clang/AST/Expr.h" 22 #include "clang/AST/ExprCXX.h" 23 #include "clang/AST/ExprObjC.h" 24 #include "clang/AST/ExprOpenMP.h" 25 #include "clang/AST/StmtCXX.h" 26 #include "clang/AST/StmtObjC.h" 27 #include "clang/Analysis/Analyses/FormatString.h" 28 #include "clang/Basic/CharInfo.h" 29 #include "clang/Basic/TargetBuiltins.h" 30 #include "clang/Basic/TargetInfo.h" 31 #include "clang/Lex/Lexer.h" // TODO: Extract static functions to fix layering. 32 #include "clang/Sema/Initialization.h" 33 #include "clang/Sema/Lookup.h" 34 #include "clang/Sema/ScopeInfo.h" 35 #include "clang/Sema/Sema.h" 36 #include "llvm/ADT/STLExtras.h" 37 #include "llvm/ADT/SmallBitVector.h" 38 #include "llvm/ADT/SmallString.h" 39 #include "llvm/Support/ConvertUTF.h" 40 #include "llvm/Support/raw_ostream.h" 41 #include <limits> 42 using namespace clang; 43 using namespace sema; 44 45 SourceLocation Sema::getLocationOfStringLiteralByte(const StringLiteral *SL, 46 unsigned ByteNo) const { 47 return SL->getLocationOfByte(ByteNo, getSourceManager(), LangOpts, 48 Context.getTargetInfo()); 49 } 50 51 /// Checks that a call expression's argument count is the desired number. 52 /// This is useful when doing custom type-checking. Returns true on error. 53 static bool checkArgCount(Sema &S, CallExpr *call, unsigned desiredArgCount) { 54 unsigned argCount = call->getNumArgs(); 55 if (argCount == desiredArgCount) return false; 56 57 if (argCount < desiredArgCount) 58 return S.Diag(call->getLocEnd(), diag::err_typecheck_call_too_few_args) 59 << 0 /*function call*/ << desiredArgCount << argCount 60 << call->getSourceRange(); 61 62 // Highlight all the excess arguments. 63 SourceRange range(call->getArg(desiredArgCount)->getLocStart(), 64 call->getArg(argCount - 1)->getLocEnd()); 65 66 return S.Diag(range.getBegin(), diag::err_typecheck_call_too_many_args) 67 << 0 /*function call*/ << desiredArgCount << argCount 68 << call->getArg(1)->getSourceRange(); 69 } 70 71 /// Check that the first argument to __builtin_annotation is an integer 72 /// and the second argument is a non-wide string literal. 73 static bool SemaBuiltinAnnotation(Sema &S, CallExpr *TheCall) { 74 if (checkArgCount(S, TheCall, 2)) 75 return true; 76 77 // First argument should be an integer. 78 Expr *ValArg = TheCall->getArg(0); 79 QualType Ty = ValArg->getType(); 80 if (!Ty->isIntegerType()) { 81 S.Diag(ValArg->getLocStart(), diag::err_builtin_annotation_first_arg) 82 << ValArg->getSourceRange(); 83 return true; 84 } 85 86 // Second argument should be a constant string. 87 Expr *StrArg = TheCall->getArg(1)->IgnoreParenCasts(); 88 StringLiteral *Literal = dyn_cast<StringLiteral>(StrArg); 89 if (!Literal || !Literal->isAscii()) { 90 S.Diag(StrArg->getLocStart(), diag::err_builtin_annotation_second_arg) 91 << StrArg->getSourceRange(); 92 return true; 93 } 94 95 TheCall->setType(Ty); 96 return false; 97 } 98 99 /// Check that the argument to __builtin_addressof is a glvalue, and set the 100 /// result type to the corresponding pointer type. 101 static bool SemaBuiltinAddressof(Sema &S, CallExpr *TheCall) { 102 if (checkArgCount(S, TheCall, 1)) 103 return true; 104 105 ExprResult Arg(TheCall->getArg(0)); 106 QualType ResultType = S.CheckAddressOfOperand(Arg, TheCall->getLocStart()); 107 if (ResultType.isNull()) 108 return true; 109 110 TheCall->setArg(0, Arg.get()); 111 TheCall->setType(ResultType); 112 return false; 113 } 114 115 static bool SemaBuiltinOverflow(Sema &S, CallExpr *TheCall) { 116 if (checkArgCount(S, TheCall, 3)) 117 return true; 118 119 // First two arguments should be integers. 120 for (unsigned I = 0; I < 2; ++I) { 121 Expr *Arg = TheCall->getArg(I); 122 QualType Ty = Arg->getType(); 123 if (!Ty->isIntegerType()) { 124 S.Diag(Arg->getLocStart(), diag::err_overflow_builtin_must_be_int) 125 << Ty << Arg->getSourceRange(); 126 return true; 127 } 128 } 129 130 // Third argument should be a pointer to a non-const integer. 131 // IRGen correctly handles volatile, restrict, and address spaces, and 132 // the other qualifiers aren't possible. 133 { 134 Expr *Arg = TheCall->getArg(2); 135 QualType Ty = Arg->getType(); 136 const auto *PtrTy = Ty->getAs<PointerType>(); 137 if (!(PtrTy && PtrTy->getPointeeType()->isIntegerType() && 138 !PtrTy->getPointeeType().isConstQualified())) { 139 S.Diag(Arg->getLocStart(), diag::err_overflow_builtin_must_be_ptr_int) 140 << Ty << Arg->getSourceRange(); 141 return true; 142 } 143 } 144 145 return false; 146 } 147 148 static void SemaBuiltinMemChkCall(Sema &S, FunctionDecl *FDecl, 149 CallExpr *TheCall, unsigned SizeIdx, 150 unsigned DstSizeIdx) { 151 if (TheCall->getNumArgs() <= SizeIdx || 152 TheCall->getNumArgs() <= DstSizeIdx) 153 return; 154 155 const Expr *SizeArg = TheCall->getArg(SizeIdx); 156 const Expr *DstSizeArg = TheCall->getArg(DstSizeIdx); 157 158 llvm::APSInt Size, DstSize; 159 160 // find out if both sizes are known at compile time 161 if (!SizeArg->EvaluateAsInt(Size, S.Context) || 162 !DstSizeArg->EvaluateAsInt(DstSize, S.Context)) 163 return; 164 165 if (Size.ule(DstSize)) 166 return; 167 168 // confirmed overflow so generate the diagnostic. 169 IdentifierInfo *FnName = FDecl->getIdentifier(); 170 SourceLocation SL = TheCall->getLocStart(); 171 SourceRange SR = TheCall->getSourceRange(); 172 173 S.Diag(SL, diag::warn_memcpy_chk_overflow) << SR << FnName; 174 } 175 176 static bool SemaBuiltinCallWithStaticChain(Sema &S, CallExpr *BuiltinCall) { 177 if (checkArgCount(S, BuiltinCall, 2)) 178 return true; 179 180 SourceLocation BuiltinLoc = BuiltinCall->getLocStart(); 181 Expr *Builtin = BuiltinCall->getCallee()->IgnoreImpCasts(); 182 Expr *Call = BuiltinCall->getArg(0); 183 Expr *Chain = BuiltinCall->getArg(1); 184 185 if (Call->getStmtClass() != Stmt::CallExprClass) { 186 S.Diag(BuiltinLoc, diag::err_first_argument_to_cwsc_not_call) 187 << Call->getSourceRange(); 188 return true; 189 } 190 191 auto CE = cast<CallExpr>(Call); 192 if (CE->getCallee()->getType()->isBlockPointerType()) { 193 S.Diag(BuiltinLoc, diag::err_first_argument_to_cwsc_block_call) 194 << Call->getSourceRange(); 195 return true; 196 } 197 198 const Decl *TargetDecl = CE->getCalleeDecl(); 199 if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(TargetDecl)) 200 if (FD->getBuiltinID()) { 201 S.Diag(BuiltinLoc, diag::err_first_argument_to_cwsc_builtin_call) 202 << Call->getSourceRange(); 203 return true; 204 } 205 206 if (isa<CXXPseudoDestructorExpr>(CE->getCallee()->IgnoreParens())) { 207 S.Diag(BuiltinLoc, diag::err_first_argument_to_cwsc_pdtor_call) 208 << Call->getSourceRange(); 209 return true; 210 } 211 212 ExprResult ChainResult = S.UsualUnaryConversions(Chain); 213 if (ChainResult.isInvalid()) 214 return true; 215 if (!ChainResult.get()->getType()->isPointerType()) { 216 S.Diag(BuiltinLoc, diag::err_second_argument_to_cwsc_not_pointer) 217 << Chain->getSourceRange(); 218 return true; 219 } 220 221 QualType ReturnTy = CE->getCallReturnType(S.Context); 222 QualType ArgTys[2] = { ReturnTy, ChainResult.get()->getType() }; 223 QualType BuiltinTy = S.Context.getFunctionType( 224 ReturnTy, ArgTys, FunctionProtoType::ExtProtoInfo()); 225 QualType BuiltinPtrTy = S.Context.getPointerType(BuiltinTy); 226 227 Builtin = 228 S.ImpCastExprToType(Builtin, BuiltinPtrTy, CK_BuiltinFnToFnPtr).get(); 229 230 BuiltinCall->setType(CE->getType()); 231 BuiltinCall->setValueKind(CE->getValueKind()); 232 BuiltinCall->setObjectKind(CE->getObjectKind()); 233 BuiltinCall->setCallee(Builtin); 234 BuiltinCall->setArg(1, ChainResult.get()); 235 236 return false; 237 } 238 239 static bool SemaBuiltinSEHScopeCheck(Sema &SemaRef, CallExpr *TheCall, 240 Scope::ScopeFlags NeededScopeFlags, 241 unsigned DiagID) { 242 // Scopes aren't available during instantiation. Fortunately, builtin 243 // functions cannot be template args so they cannot be formed through template 244 // instantiation. Therefore checking once during the parse is sufficient. 245 if (!SemaRef.ActiveTemplateInstantiations.empty()) 246 return false; 247 248 Scope *S = SemaRef.getCurScope(); 249 while (S && !S->isSEHExceptScope()) 250 S = S->getParent(); 251 if (!S || !(S->getFlags() & NeededScopeFlags)) { 252 auto *DRE = cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts()); 253 SemaRef.Diag(TheCall->getExprLoc(), DiagID) 254 << DRE->getDecl()->getIdentifier(); 255 return true; 256 } 257 258 return false; 259 } 260 261 ExprResult 262 Sema::CheckBuiltinFunctionCall(FunctionDecl *FDecl, unsigned BuiltinID, 263 CallExpr *TheCall) { 264 ExprResult TheCallResult(TheCall); 265 266 // Find out if any arguments are required to be integer constant expressions. 267 unsigned ICEArguments = 0; 268 ASTContext::GetBuiltinTypeError Error; 269 Context.GetBuiltinType(BuiltinID, Error, &ICEArguments); 270 if (Error != ASTContext::GE_None) 271 ICEArguments = 0; // Don't diagnose previously diagnosed errors. 272 273 // If any arguments are required to be ICE's, check and diagnose. 274 for (unsigned ArgNo = 0; ICEArguments != 0; ++ArgNo) { 275 // Skip arguments not required to be ICE's. 276 if ((ICEArguments & (1 << ArgNo)) == 0) continue; 277 278 llvm::APSInt Result; 279 if (SemaBuiltinConstantArg(TheCall, ArgNo, Result)) 280 return true; 281 ICEArguments &= ~(1 << ArgNo); 282 } 283 284 switch (BuiltinID) { 285 case Builtin::BI__builtin___CFStringMakeConstantString: 286 assert(TheCall->getNumArgs() == 1 && 287 "Wrong # arguments to builtin CFStringMakeConstantString"); 288 if (CheckObjCString(TheCall->getArg(0))) 289 return ExprError(); 290 break; 291 case Builtin::BI__builtin_stdarg_start: 292 case Builtin::BI__builtin_va_start: 293 if (SemaBuiltinVAStart(TheCall)) 294 return ExprError(); 295 break; 296 case Builtin::BI__va_start: { 297 switch (Context.getTargetInfo().getTriple().getArch()) { 298 case llvm::Triple::arm: 299 case llvm::Triple::thumb: 300 if (SemaBuiltinVAStartARM(TheCall)) 301 return ExprError(); 302 break; 303 default: 304 if (SemaBuiltinVAStart(TheCall)) 305 return ExprError(); 306 break; 307 } 308 break; 309 } 310 case Builtin::BI__builtin_isgreater: 311 case Builtin::BI__builtin_isgreaterequal: 312 case Builtin::BI__builtin_isless: 313 case Builtin::BI__builtin_islessequal: 314 case Builtin::BI__builtin_islessgreater: 315 case Builtin::BI__builtin_isunordered: 316 if (SemaBuiltinUnorderedCompare(TheCall)) 317 return ExprError(); 318 break; 319 case Builtin::BI__builtin_fpclassify: 320 if (SemaBuiltinFPClassification(TheCall, 6)) 321 return ExprError(); 322 break; 323 case Builtin::BI__builtin_isfinite: 324 case Builtin::BI__builtin_isinf: 325 case Builtin::BI__builtin_isinf_sign: 326 case Builtin::BI__builtin_isnan: 327 case Builtin::BI__builtin_isnormal: 328 if (SemaBuiltinFPClassification(TheCall, 1)) 329 return ExprError(); 330 break; 331 case Builtin::BI__builtin_shufflevector: 332 return SemaBuiltinShuffleVector(TheCall); 333 // TheCall will be freed by the smart pointer here, but that's fine, since 334 // SemaBuiltinShuffleVector guts it, but then doesn't release it. 335 case Builtin::BI__builtin_prefetch: 336 if (SemaBuiltinPrefetch(TheCall)) 337 return ExprError(); 338 break; 339 case Builtin::BI__assume: 340 case Builtin::BI__builtin_assume: 341 if (SemaBuiltinAssume(TheCall)) 342 return ExprError(); 343 break; 344 case Builtin::BI__builtin_assume_aligned: 345 if (SemaBuiltinAssumeAligned(TheCall)) 346 return ExprError(); 347 break; 348 case Builtin::BI__builtin_object_size: 349 if (SemaBuiltinConstantArgRange(TheCall, 1, 0, 3)) 350 return ExprError(); 351 break; 352 case Builtin::BI__builtin_longjmp: 353 if (SemaBuiltinLongjmp(TheCall)) 354 return ExprError(); 355 break; 356 case Builtin::BI__builtin_setjmp: 357 if (SemaBuiltinSetjmp(TheCall)) 358 return ExprError(); 359 break; 360 case Builtin::BI_setjmp: 361 case Builtin::BI_setjmpex: 362 if (checkArgCount(*this, TheCall, 1)) 363 return true; 364 break; 365 366 case Builtin::BI__builtin_classify_type: 367 if (checkArgCount(*this, TheCall, 1)) return true; 368 TheCall->setType(Context.IntTy); 369 break; 370 case Builtin::BI__builtin_constant_p: 371 if (checkArgCount(*this, TheCall, 1)) return true; 372 TheCall->setType(Context.IntTy); 373 break; 374 case Builtin::BI__sync_fetch_and_add: 375 case Builtin::BI__sync_fetch_and_add_1: 376 case Builtin::BI__sync_fetch_and_add_2: 377 case Builtin::BI__sync_fetch_and_add_4: 378 case Builtin::BI__sync_fetch_and_add_8: 379 case Builtin::BI__sync_fetch_and_add_16: 380 case Builtin::BI__sync_fetch_and_sub: 381 case Builtin::BI__sync_fetch_and_sub_1: 382 case Builtin::BI__sync_fetch_and_sub_2: 383 case Builtin::BI__sync_fetch_and_sub_4: 384 case Builtin::BI__sync_fetch_and_sub_8: 385 case Builtin::BI__sync_fetch_and_sub_16: 386 case Builtin::BI__sync_fetch_and_or: 387 case Builtin::BI__sync_fetch_and_or_1: 388 case Builtin::BI__sync_fetch_and_or_2: 389 case Builtin::BI__sync_fetch_and_or_4: 390 case Builtin::BI__sync_fetch_and_or_8: 391 case Builtin::BI__sync_fetch_and_or_16: 392 case Builtin::BI__sync_fetch_and_and: 393 case Builtin::BI__sync_fetch_and_and_1: 394 case Builtin::BI__sync_fetch_and_and_2: 395 case Builtin::BI__sync_fetch_and_and_4: 396 case Builtin::BI__sync_fetch_and_and_8: 397 case Builtin::BI__sync_fetch_and_and_16: 398 case Builtin::BI__sync_fetch_and_xor: 399 case Builtin::BI__sync_fetch_and_xor_1: 400 case Builtin::BI__sync_fetch_and_xor_2: 401 case Builtin::BI__sync_fetch_and_xor_4: 402 case Builtin::BI__sync_fetch_and_xor_8: 403 case Builtin::BI__sync_fetch_and_xor_16: 404 case Builtin::BI__sync_fetch_and_nand: 405 case Builtin::BI__sync_fetch_and_nand_1: 406 case Builtin::BI__sync_fetch_and_nand_2: 407 case Builtin::BI__sync_fetch_and_nand_4: 408 case Builtin::BI__sync_fetch_and_nand_8: 409 case Builtin::BI__sync_fetch_and_nand_16: 410 case Builtin::BI__sync_add_and_fetch: 411 case Builtin::BI__sync_add_and_fetch_1: 412 case Builtin::BI__sync_add_and_fetch_2: 413 case Builtin::BI__sync_add_and_fetch_4: 414 case Builtin::BI__sync_add_and_fetch_8: 415 case Builtin::BI__sync_add_and_fetch_16: 416 case Builtin::BI__sync_sub_and_fetch: 417 case Builtin::BI__sync_sub_and_fetch_1: 418 case Builtin::BI__sync_sub_and_fetch_2: 419 case Builtin::BI__sync_sub_and_fetch_4: 420 case Builtin::BI__sync_sub_and_fetch_8: 421 case Builtin::BI__sync_sub_and_fetch_16: 422 case Builtin::BI__sync_and_and_fetch: 423 case Builtin::BI__sync_and_and_fetch_1: 424 case Builtin::BI__sync_and_and_fetch_2: 425 case Builtin::BI__sync_and_and_fetch_4: 426 case Builtin::BI__sync_and_and_fetch_8: 427 case Builtin::BI__sync_and_and_fetch_16: 428 case Builtin::BI__sync_or_and_fetch: 429 case Builtin::BI__sync_or_and_fetch_1: 430 case Builtin::BI__sync_or_and_fetch_2: 431 case Builtin::BI__sync_or_and_fetch_4: 432 case Builtin::BI__sync_or_and_fetch_8: 433 case Builtin::BI__sync_or_and_fetch_16: 434 case Builtin::BI__sync_xor_and_fetch: 435 case Builtin::BI__sync_xor_and_fetch_1: 436 case Builtin::BI__sync_xor_and_fetch_2: 437 case Builtin::BI__sync_xor_and_fetch_4: 438 case Builtin::BI__sync_xor_and_fetch_8: 439 case Builtin::BI__sync_xor_and_fetch_16: 440 case Builtin::BI__sync_nand_and_fetch: 441 case Builtin::BI__sync_nand_and_fetch_1: 442 case Builtin::BI__sync_nand_and_fetch_2: 443 case Builtin::BI__sync_nand_and_fetch_4: 444 case Builtin::BI__sync_nand_and_fetch_8: 445 case Builtin::BI__sync_nand_and_fetch_16: 446 case Builtin::BI__sync_val_compare_and_swap: 447 case Builtin::BI__sync_val_compare_and_swap_1: 448 case Builtin::BI__sync_val_compare_and_swap_2: 449 case Builtin::BI__sync_val_compare_and_swap_4: 450 case Builtin::BI__sync_val_compare_and_swap_8: 451 case Builtin::BI__sync_val_compare_and_swap_16: 452 case Builtin::BI__sync_bool_compare_and_swap: 453 case Builtin::BI__sync_bool_compare_and_swap_1: 454 case Builtin::BI__sync_bool_compare_and_swap_2: 455 case Builtin::BI__sync_bool_compare_and_swap_4: 456 case Builtin::BI__sync_bool_compare_and_swap_8: 457 case Builtin::BI__sync_bool_compare_and_swap_16: 458 case Builtin::BI__sync_lock_test_and_set: 459 case Builtin::BI__sync_lock_test_and_set_1: 460 case Builtin::BI__sync_lock_test_and_set_2: 461 case Builtin::BI__sync_lock_test_and_set_4: 462 case Builtin::BI__sync_lock_test_and_set_8: 463 case Builtin::BI__sync_lock_test_and_set_16: 464 case Builtin::BI__sync_lock_release: 465 case Builtin::BI__sync_lock_release_1: 466 case Builtin::BI__sync_lock_release_2: 467 case Builtin::BI__sync_lock_release_4: 468 case Builtin::BI__sync_lock_release_8: 469 case Builtin::BI__sync_lock_release_16: 470 case Builtin::BI__sync_swap: 471 case Builtin::BI__sync_swap_1: 472 case Builtin::BI__sync_swap_2: 473 case Builtin::BI__sync_swap_4: 474 case Builtin::BI__sync_swap_8: 475 case Builtin::BI__sync_swap_16: 476 return SemaBuiltinAtomicOverloaded(TheCallResult); 477 case Builtin::BI__builtin_nontemporal_load: 478 case Builtin::BI__builtin_nontemporal_store: 479 return SemaBuiltinNontemporalOverloaded(TheCallResult); 480 #define BUILTIN(ID, TYPE, ATTRS) 481 #define ATOMIC_BUILTIN(ID, TYPE, ATTRS) \ 482 case Builtin::BI##ID: \ 483 return SemaAtomicOpsOverloaded(TheCallResult, AtomicExpr::AO##ID); 484 #include "clang/Basic/Builtins.def" 485 case Builtin::BI__builtin_annotation: 486 if (SemaBuiltinAnnotation(*this, TheCall)) 487 return ExprError(); 488 break; 489 case Builtin::BI__builtin_addressof: 490 if (SemaBuiltinAddressof(*this, TheCall)) 491 return ExprError(); 492 break; 493 case Builtin::BI__builtin_add_overflow: 494 case Builtin::BI__builtin_sub_overflow: 495 case Builtin::BI__builtin_mul_overflow: 496 if (SemaBuiltinOverflow(*this, TheCall)) 497 return ExprError(); 498 break; 499 case Builtin::BI__builtin_operator_new: 500 case Builtin::BI__builtin_operator_delete: 501 if (!getLangOpts().CPlusPlus) { 502 Diag(TheCall->getExprLoc(), diag::err_builtin_requires_language) 503 << (BuiltinID == Builtin::BI__builtin_operator_new 504 ? "__builtin_operator_new" 505 : "__builtin_operator_delete") 506 << "C++"; 507 return ExprError(); 508 } 509 // CodeGen assumes it can find the global new and delete to call, 510 // so ensure that they are declared. 511 DeclareGlobalNewDelete(); 512 break; 513 514 // check secure string manipulation functions where overflows 515 // are detectable at compile time 516 case Builtin::BI__builtin___memcpy_chk: 517 case Builtin::BI__builtin___memmove_chk: 518 case Builtin::BI__builtin___memset_chk: 519 case Builtin::BI__builtin___strlcat_chk: 520 case Builtin::BI__builtin___strlcpy_chk: 521 case Builtin::BI__builtin___strncat_chk: 522 case Builtin::BI__builtin___strncpy_chk: 523 case Builtin::BI__builtin___stpncpy_chk: 524 SemaBuiltinMemChkCall(*this, FDecl, TheCall, 2, 3); 525 break; 526 case Builtin::BI__builtin___memccpy_chk: 527 SemaBuiltinMemChkCall(*this, FDecl, TheCall, 3, 4); 528 break; 529 case Builtin::BI__builtin___snprintf_chk: 530 case Builtin::BI__builtin___vsnprintf_chk: 531 SemaBuiltinMemChkCall(*this, FDecl, TheCall, 1, 3); 532 break; 533 534 case Builtin::BI__builtin_call_with_static_chain: 535 if (SemaBuiltinCallWithStaticChain(*this, TheCall)) 536 return ExprError(); 537 break; 538 539 case Builtin::BI__exception_code: 540 case Builtin::BI_exception_code: { 541 if (SemaBuiltinSEHScopeCheck(*this, TheCall, Scope::SEHExceptScope, 542 diag::err_seh___except_block)) 543 return ExprError(); 544 break; 545 } 546 case Builtin::BI__exception_info: 547 case Builtin::BI_exception_info: { 548 if (SemaBuiltinSEHScopeCheck(*this, TheCall, Scope::SEHFilterScope, 549 diag::err_seh___except_filter)) 550 return ExprError(); 551 break; 552 } 553 554 case Builtin::BI__GetExceptionInfo: 555 if (checkArgCount(*this, TheCall, 1)) 556 return ExprError(); 557 558 if (CheckCXXThrowOperand( 559 TheCall->getLocStart(), 560 Context.getExceptionObjectType(FDecl->getParamDecl(0)->getType()), 561 TheCall)) 562 return ExprError(); 563 564 TheCall->setType(Context.VoidPtrTy); 565 break; 566 567 } 568 569 // Since the target specific builtins for each arch overlap, only check those 570 // of the arch we are compiling for. 571 if (Context.BuiltinInfo.isTSBuiltin(BuiltinID)) { 572 switch (Context.getTargetInfo().getTriple().getArch()) { 573 case llvm::Triple::arm: 574 case llvm::Triple::armeb: 575 case llvm::Triple::thumb: 576 case llvm::Triple::thumbeb: 577 if (CheckARMBuiltinFunctionCall(BuiltinID, TheCall)) 578 return ExprError(); 579 break; 580 case llvm::Triple::aarch64: 581 case llvm::Triple::aarch64_be: 582 if (CheckAArch64BuiltinFunctionCall(BuiltinID, TheCall)) 583 return ExprError(); 584 break; 585 case llvm::Triple::mips: 586 case llvm::Triple::mipsel: 587 case llvm::Triple::mips64: 588 case llvm::Triple::mips64el: 589 if (CheckMipsBuiltinFunctionCall(BuiltinID, TheCall)) 590 return ExprError(); 591 break; 592 case llvm::Triple::systemz: 593 if (CheckSystemZBuiltinFunctionCall(BuiltinID, TheCall)) 594 return ExprError(); 595 break; 596 case llvm::Triple::x86: 597 case llvm::Triple::x86_64: 598 if (CheckX86BuiltinFunctionCall(BuiltinID, TheCall)) 599 return ExprError(); 600 break; 601 case llvm::Triple::ppc: 602 case llvm::Triple::ppc64: 603 case llvm::Triple::ppc64le: 604 if (CheckPPCBuiltinFunctionCall(BuiltinID, TheCall)) 605 return ExprError(); 606 break; 607 default: 608 break; 609 } 610 } 611 612 return TheCallResult; 613 } 614 615 // Get the valid immediate range for the specified NEON type code. 616 static unsigned RFT(unsigned t, bool shift = false, bool ForceQuad = false) { 617 NeonTypeFlags Type(t); 618 int IsQuad = ForceQuad ? true : Type.isQuad(); 619 switch (Type.getEltType()) { 620 case NeonTypeFlags::Int8: 621 case NeonTypeFlags::Poly8: 622 return shift ? 7 : (8 << IsQuad) - 1; 623 case NeonTypeFlags::Int16: 624 case NeonTypeFlags::Poly16: 625 return shift ? 15 : (4 << IsQuad) - 1; 626 case NeonTypeFlags::Int32: 627 return shift ? 31 : (2 << IsQuad) - 1; 628 case NeonTypeFlags::Int64: 629 case NeonTypeFlags::Poly64: 630 return shift ? 63 : (1 << IsQuad) - 1; 631 case NeonTypeFlags::Poly128: 632 return shift ? 127 : (1 << IsQuad) - 1; 633 case NeonTypeFlags::Float16: 634 assert(!shift && "cannot shift float types!"); 635 return (4 << IsQuad) - 1; 636 case NeonTypeFlags::Float32: 637 assert(!shift && "cannot shift float types!"); 638 return (2 << IsQuad) - 1; 639 case NeonTypeFlags::Float64: 640 assert(!shift && "cannot shift float types!"); 641 return (1 << IsQuad) - 1; 642 } 643 llvm_unreachable("Invalid NeonTypeFlag!"); 644 } 645 646 /// getNeonEltType - Return the QualType corresponding to the elements of 647 /// the vector type specified by the NeonTypeFlags. This is used to check 648 /// the pointer arguments for Neon load/store intrinsics. 649 static QualType getNeonEltType(NeonTypeFlags Flags, ASTContext &Context, 650 bool IsPolyUnsigned, bool IsInt64Long) { 651 switch (Flags.getEltType()) { 652 case NeonTypeFlags::Int8: 653 return Flags.isUnsigned() ? Context.UnsignedCharTy : Context.SignedCharTy; 654 case NeonTypeFlags::Int16: 655 return Flags.isUnsigned() ? Context.UnsignedShortTy : Context.ShortTy; 656 case NeonTypeFlags::Int32: 657 return Flags.isUnsigned() ? Context.UnsignedIntTy : Context.IntTy; 658 case NeonTypeFlags::Int64: 659 if (IsInt64Long) 660 return Flags.isUnsigned() ? Context.UnsignedLongTy : Context.LongTy; 661 else 662 return Flags.isUnsigned() ? Context.UnsignedLongLongTy 663 : Context.LongLongTy; 664 case NeonTypeFlags::Poly8: 665 return IsPolyUnsigned ? Context.UnsignedCharTy : Context.SignedCharTy; 666 case NeonTypeFlags::Poly16: 667 return IsPolyUnsigned ? Context.UnsignedShortTy : Context.ShortTy; 668 case NeonTypeFlags::Poly64: 669 if (IsInt64Long) 670 return Context.UnsignedLongTy; 671 else 672 return Context.UnsignedLongLongTy; 673 case NeonTypeFlags::Poly128: 674 break; 675 case NeonTypeFlags::Float16: 676 return Context.HalfTy; 677 case NeonTypeFlags::Float32: 678 return Context.FloatTy; 679 case NeonTypeFlags::Float64: 680 return Context.DoubleTy; 681 } 682 llvm_unreachable("Invalid NeonTypeFlag!"); 683 } 684 685 bool Sema::CheckNeonBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) { 686 llvm::APSInt Result; 687 uint64_t mask = 0; 688 unsigned TV = 0; 689 int PtrArgNum = -1; 690 bool HasConstPtr = false; 691 switch (BuiltinID) { 692 #define GET_NEON_OVERLOAD_CHECK 693 #include "clang/Basic/arm_neon.inc" 694 #undef GET_NEON_OVERLOAD_CHECK 695 } 696 697 // For NEON intrinsics which are overloaded on vector element type, validate 698 // the immediate which specifies which variant to emit. 699 unsigned ImmArg = TheCall->getNumArgs()-1; 700 if (mask) { 701 if (SemaBuiltinConstantArg(TheCall, ImmArg, Result)) 702 return true; 703 704 TV = Result.getLimitedValue(64); 705 if ((TV > 63) || (mask & (1ULL << TV)) == 0) 706 return Diag(TheCall->getLocStart(), diag::err_invalid_neon_type_code) 707 << TheCall->getArg(ImmArg)->getSourceRange(); 708 } 709 710 if (PtrArgNum >= 0) { 711 // Check that pointer arguments have the specified type. 712 Expr *Arg = TheCall->getArg(PtrArgNum); 713 if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(Arg)) 714 Arg = ICE->getSubExpr(); 715 ExprResult RHS = DefaultFunctionArrayLvalueConversion(Arg); 716 QualType RHSTy = RHS.get()->getType(); 717 718 llvm::Triple::ArchType Arch = Context.getTargetInfo().getTriple().getArch(); 719 bool IsPolyUnsigned = Arch == llvm::Triple::aarch64; 720 bool IsInt64Long = 721 Context.getTargetInfo().getInt64Type() == TargetInfo::SignedLong; 722 QualType EltTy = 723 getNeonEltType(NeonTypeFlags(TV), Context, IsPolyUnsigned, IsInt64Long); 724 if (HasConstPtr) 725 EltTy = EltTy.withConst(); 726 QualType LHSTy = Context.getPointerType(EltTy); 727 AssignConvertType ConvTy; 728 ConvTy = CheckSingleAssignmentConstraints(LHSTy, RHS); 729 if (RHS.isInvalid()) 730 return true; 731 if (DiagnoseAssignmentResult(ConvTy, Arg->getLocStart(), LHSTy, RHSTy, 732 RHS.get(), AA_Assigning)) 733 return true; 734 } 735 736 // For NEON intrinsics which take an immediate value as part of the 737 // instruction, range check them here. 738 unsigned i = 0, l = 0, u = 0; 739 switch (BuiltinID) { 740 default: 741 return false; 742 #define GET_NEON_IMMEDIATE_CHECK 743 #include "clang/Basic/arm_neon.inc" 744 #undef GET_NEON_IMMEDIATE_CHECK 745 } 746 747 return SemaBuiltinConstantArgRange(TheCall, i, l, u + l); 748 } 749 750 bool Sema::CheckARMBuiltinExclusiveCall(unsigned BuiltinID, CallExpr *TheCall, 751 unsigned MaxWidth) { 752 assert((BuiltinID == ARM::BI__builtin_arm_ldrex || 753 BuiltinID == ARM::BI__builtin_arm_ldaex || 754 BuiltinID == ARM::BI__builtin_arm_strex || 755 BuiltinID == ARM::BI__builtin_arm_stlex || 756 BuiltinID == AArch64::BI__builtin_arm_ldrex || 757 BuiltinID == AArch64::BI__builtin_arm_ldaex || 758 BuiltinID == AArch64::BI__builtin_arm_strex || 759 BuiltinID == AArch64::BI__builtin_arm_stlex) && 760 "unexpected ARM builtin"); 761 bool IsLdrex = BuiltinID == ARM::BI__builtin_arm_ldrex || 762 BuiltinID == ARM::BI__builtin_arm_ldaex || 763 BuiltinID == AArch64::BI__builtin_arm_ldrex || 764 BuiltinID == AArch64::BI__builtin_arm_ldaex; 765 766 DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts()); 767 768 // Ensure that we have the proper number of arguments. 769 if (checkArgCount(*this, TheCall, IsLdrex ? 1 : 2)) 770 return true; 771 772 // Inspect the pointer argument of the atomic builtin. This should always be 773 // a pointer type, whose element is an integral scalar or pointer type. 774 // Because it is a pointer type, we don't have to worry about any implicit 775 // casts here. 776 Expr *PointerArg = TheCall->getArg(IsLdrex ? 0 : 1); 777 ExprResult PointerArgRes = DefaultFunctionArrayLvalueConversion(PointerArg); 778 if (PointerArgRes.isInvalid()) 779 return true; 780 PointerArg = PointerArgRes.get(); 781 782 const PointerType *pointerType = PointerArg->getType()->getAs<PointerType>(); 783 if (!pointerType) { 784 Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer) 785 << PointerArg->getType() << PointerArg->getSourceRange(); 786 return true; 787 } 788 789 // ldrex takes a "const volatile T*" and strex takes a "volatile T*". Our next 790 // task is to insert the appropriate casts into the AST. First work out just 791 // what the appropriate type is. 792 QualType ValType = pointerType->getPointeeType(); 793 QualType AddrType = ValType.getUnqualifiedType().withVolatile(); 794 if (IsLdrex) 795 AddrType.addConst(); 796 797 // Issue a warning if the cast is dodgy. 798 CastKind CastNeeded = CK_NoOp; 799 if (!AddrType.isAtLeastAsQualifiedAs(ValType)) { 800 CastNeeded = CK_BitCast; 801 Diag(DRE->getLocStart(), diag::ext_typecheck_convert_discards_qualifiers) 802 << PointerArg->getType() 803 << Context.getPointerType(AddrType) 804 << AA_Passing << PointerArg->getSourceRange(); 805 } 806 807 // Finally, do the cast and replace the argument with the corrected version. 808 AddrType = Context.getPointerType(AddrType); 809 PointerArgRes = ImpCastExprToType(PointerArg, AddrType, CastNeeded); 810 if (PointerArgRes.isInvalid()) 811 return true; 812 PointerArg = PointerArgRes.get(); 813 814 TheCall->setArg(IsLdrex ? 0 : 1, PointerArg); 815 816 // In general, we allow ints, floats and pointers to be loaded and stored. 817 if (!ValType->isIntegerType() && !ValType->isAnyPointerType() && 818 !ValType->isBlockPointerType() && !ValType->isFloatingType()) { 819 Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer_intfltptr) 820 << PointerArg->getType() << PointerArg->getSourceRange(); 821 return true; 822 } 823 824 // But ARM doesn't have instructions to deal with 128-bit versions. 825 if (Context.getTypeSize(ValType) > MaxWidth) { 826 assert(MaxWidth == 64 && "Diagnostic unexpectedly inaccurate"); 827 Diag(DRE->getLocStart(), diag::err_atomic_exclusive_builtin_pointer_size) 828 << PointerArg->getType() << PointerArg->getSourceRange(); 829 return true; 830 } 831 832 switch (ValType.getObjCLifetime()) { 833 case Qualifiers::OCL_None: 834 case Qualifiers::OCL_ExplicitNone: 835 // okay 836 break; 837 838 case Qualifiers::OCL_Weak: 839 case Qualifiers::OCL_Strong: 840 case Qualifiers::OCL_Autoreleasing: 841 Diag(DRE->getLocStart(), diag::err_arc_atomic_ownership) 842 << ValType << PointerArg->getSourceRange(); 843 return true; 844 } 845 846 847 if (IsLdrex) { 848 TheCall->setType(ValType); 849 return false; 850 } 851 852 // Initialize the argument to be stored. 853 ExprResult ValArg = TheCall->getArg(0); 854 InitializedEntity Entity = InitializedEntity::InitializeParameter( 855 Context, ValType, /*consume*/ false); 856 ValArg = PerformCopyInitialization(Entity, SourceLocation(), ValArg); 857 if (ValArg.isInvalid()) 858 return true; 859 TheCall->setArg(0, ValArg.get()); 860 861 // __builtin_arm_strex always returns an int. It's marked as such in the .def, 862 // but the custom checker bypasses all default analysis. 863 TheCall->setType(Context.IntTy); 864 return false; 865 } 866 867 bool Sema::CheckARMBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) { 868 llvm::APSInt Result; 869 870 if (BuiltinID == ARM::BI__builtin_arm_ldrex || 871 BuiltinID == ARM::BI__builtin_arm_ldaex || 872 BuiltinID == ARM::BI__builtin_arm_strex || 873 BuiltinID == ARM::BI__builtin_arm_stlex) { 874 return CheckARMBuiltinExclusiveCall(BuiltinID, TheCall, 64); 875 } 876 877 if (BuiltinID == ARM::BI__builtin_arm_prefetch) { 878 return SemaBuiltinConstantArgRange(TheCall, 1, 0, 1) || 879 SemaBuiltinConstantArgRange(TheCall, 2, 0, 1); 880 } 881 882 if (BuiltinID == ARM::BI__builtin_arm_rsr64 || 883 BuiltinID == ARM::BI__builtin_arm_wsr64) 884 return SemaBuiltinARMSpecialReg(BuiltinID, TheCall, 0, 3, false); 885 886 if (BuiltinID == ARM::BI__builtin_arm_rsr || 887 BuiltinID == ARM::BI__builtin_arm_rsrp || 888 BuiltinID == ARM::BI__builtin_arm_wsr || 889 BuiltinID == ARM::BI__builtin_arm_wsrp) 890 return SemaBuiltinARMSpecialReg(BuiltinID, TheCall, 0, 5, true); 891 892 if (CheckNeonBuiltinFunctionCall(BuiltinID, TheCall)) 893 return true; 894 895 // For intrinsics which take an immediate value as part of the instruction, 896 // range check them here. 897 unsigned i = 0, l = 0, u = 0; 898 switch (BuiltinID) { 899 default: return false; 900 case ARM::BI__builtin_arm_ssat: i = 1; l = 1; u = 31; break; 901 case ARM::BI__builtin_arm_usat: i = 1; u = 31; break; 902 case ARM::BI__builtin_arm_vcvtr_f: 903 case ARM::BI__builtin_arm_vcvtr_d: i = 1; u = 1; break; 904 case ARM::BI__builtin_arm_dmb: 905 case ARM::BI__builtin_arm_dsb: 906 case ARM::BI__builtin_arm_isb: 907 case ARM::BI__builtin_arm_dbg: l = 0; u = 15; break; 908 } 909 910 // FIXME: VFP Intrinsics should error if VFP not present. 911 return SemaBuiltinConstantArgRange(TheCall, i, l, u + l); 912 } 913 914 bool Sema::CheckAArch64BuiltinFunctionCall(unsigned BuiltinID, 915 CallExpr *TheCall) { 916 llvm::APSInt Result; 917 918 if (BuiltinID == AArch64::BI__builtin_arm_ldrex || 919 BuiltinID == AArch64::BI__builtin_arm_ldaex || 920 BuiltinID == AArch64::BI__builtin_arm_strex || 921 BuiltinID == AArch64::BI__builtin_arm_stlex) { 922 return CheckARMBuiltinExclusiveCall(BuiltinID, TheCall, 128); 923 } 924 925 if (BuiltinID == AArch64::BI__builtin_arm_prefetch) { 926 return SemaBuiltinConstantArgRange(TheCall, 1, 0, 1) || 927 SemaBuiltinConstantArgRange(TheCall, 2, 0, 2) || 928 SemaBuiltinConstantArgRange(TheCall, 3, 0, 1) || 929 SemaBuiltinConstantArgRange(TheCall, 4, 0, 1); 930 } 931 932 if (BuiltinID == AArch64::BI__builtin_arm_rsr64 || 933 BuiltinID == AArch64::BI__builtin_arm_wsr64) 934 return SemaBuiltinARMSpecialReg(BuiltinID, TheCall, 0, 5, false); 935 936 if (BuiltinID == AArch64::BI__builtin_arm_rsr || 937 BuiltinID == AArch64::BI__builtin_arm_rsrp || 938 BuiltinID == AArch64::BI__builtin_arm_wsr || 939 BuiltinID == AArch64::BI__builtin_arm_wsrp) 940 return SemaBuiltinARMSpecialReg(BuiltinID, TheCall, 0, 5, true); 941 942 if (CheckNeonBuiltinFunctionCall(BuiltinID, TheCall)) 943 return true; 944 945 // For intrinsics which take an immediate value as part of the instruction, 946 // range check them here. 947 unsigned i = 0, l = 0, u = 0; 948 switch (BuiltinID) { 949 default: return false; 950 case AArch64::BI__builtin_arm_dmb: 951 case AArch64::BI__builtin_arm_dsb: 952 case AArch64::BI__builtin_arm_isb: l = 0; u = 15; break; 953 } 954 955 return SemaBuiltinConstantArgRange(TheCall, i, l, u + l); 956 } 957 958 bool Sema::CheckMipsBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) { 959 unsigned i = 0, l = 0, u = 0; 960 switch (BuiltinID) { 961 default: return false; 962 case Mips::BI__builtin_mips_wrdsp: i = 1; l = 0; u = 63; break; 963 case Mips::BI__builtin_mips_rddsp: i = 0; l = 0; u = 63; break; 964 case Mips::BI__builtin_mips_append: i = 2; l = 0; u = 31; break; 965 case Mips::BI__builtin_mips_balign: i = 2; l = 0; u = 3; break; 966 case Mips::BI__builtin_mips_precr_sra_ph_w: i = 2; l = 0; u = 31; break; 967 case Mips::BI__builtin_mips_precr_sra_r_ph_w: i = 2; l = 0; u = 31; break; 968 case Mips::BI__builtin_mips_prepend: i = 2; l = 0; u = 31; break; 969 } 970 971 return SemaBuiltinConstantArgRange(TheCall, i, l, u); 972 } 973 974 bool Sema::CheckPPCBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) { 975 unsigned i = 0, l = 0, u = 0; 976 bool Is64BitBltin = BuiltinID == PPC::BI__builtin_divde || 977 BuiltinID == PPC::BI__builtin_divdeu || 978 BuiltinID == PPC::BI__builtin_bpermd; 979 bool IsTarget64Bit = Context.getTargetInfo() 980 .getTypeWidth(Context 981 .getTargetInfo() 982 .getIntPtrType()) == 64; 983 bool IsBltinExtDiv = BuiltinID == PPC::BI__builtin_divwe || 984 BuiltinID == PPC::BI__builtin_divweu || 985 BuiltinID == PPC::BI__builtin_divde || 986 BuiltinID == PPC::BI__builtin_divdeu; 987 988 if (Is64BitBltin && !IsTarget64Bit) 989 return Diag(TheCall->getLocStart(), diag::err_64_bit_builtin_32_bit_tgt) 990 << TheCall->getSourceRange(); 991 992 if ((IsBltinExtDiv && !Context.getTargetInfo().hasFeature("extdiv")) || 993 (BuiltinID == PPC::BI__builtin_bpermd && 994 !Context.getTargetInfo().hasFeature("bpermd"))) 995 return Diag(TheCall->getLocStart(), diag::err_ppc_builtin_only_on_pwr7) 996 << TheCall->getSourceRange(); 997 998 switch (BuiltinID) { 999 default: return false; 1000 case PPC::BI__builtin_altivec_crypto_vshasigmaw: 1001 case PPC::BI__builtin_altivec_crypto_vshasigmad: 1002 return SemaBuiltinConstantArgRange(TheCall, 1, 0, 1) || 1003 SemaBuiltinConstantArgRange(TheCall, 2, 0, 15); 1004 case PPC::BI__builtin_tbegin: 1005 case PPC::BI__builtin_tend: i = 0; l = 0; u = 1; break; 1006 case PPC::BI__builtin_tsr: i = 0; l = 0; u = 7; break; 1007 case PPC::BI__builtin_tabortwc: 1008 case PPC::BI__builtin_tabortdc: i = 0; l = 0; u = 31; break; 1009 case PPC::BI__builtin_tabortwci: 1010 case PPC::BI__builtin_tabortdci: 1011 return SemaBuiltinConstantArgRange(TheCall, 0, 0, 31) || 1012 SemaBuiltinConstantArgRange(TheCall, 2, 0, 31); 1013 } 1014 return SemaBuiltinConstantArgRange(TheCall, i, l, u); 1015 } 1016 1017 bool Sema::CheckSystemZBuiltinFunctionCall(unsigned BuiltinID, 1018 CallExpr *TheCall) { 1019 if (BuiltinID == SystemZ::BI__builtin_tabort) { 1020 Expr *Arg = TheCall->getArg(0); 1021 llvm::APSInt AbortCode(32); 1022 if (Arg->isIntegerConstantExpr(AbortCode, Context) && 1023 AbortCode.getSExtValue() >= 0 && AbortCode.getSExtValue() < 256) 1024 return Diag(Arg->getLocStart(), diag::err_systemz_invalid_tabort_code) 1025 << Arg->getSourceRange(); 1026 } 1027 1028 // For intrinsics which take an immediate value as part of the instruction, 1029 // range check them here. 1030 unsigned i = 0, l = 0, u = 0; 1031 switch (BuiltinID) { 1032 default: return false; 1033 case SystemZ::BI__builtin_s390_lcbb: i = 1; l = 0; u = 15; break; 1034 case SystemZ::BI__builtin_s390_verimb: 1035 case SystemZ::BI__builtin_s390_verimh: 1036 case SystemZ::BI__builtin_s390_verimf: 1037 case SystemZ::BI__builtin_s390_verimg: i = 3; l = 0; u = 255; break; 1038 case SystemZ::BI__builtin_s390_vfaeb: 1039 case SystemZ::BI__builtin_s390_vfaeh: 1040 case SystemZ::BI__builtin_s390_vfaef: 1041 case SystemZ::BI__builtin_s390_vfaebs: 1042 case SystemZ::BI__builtin_s390_vfaehs: 1043 case SystemZ::BI__builtin_s390_vfaefs: 1044 case SystemZ::BI__builtin_s390_vfaezb: 1045 case SystemZ::BI__builtin_s390_vfaezh: 1046 case SystemZ::BI__builtin_s390_vfaezf: 1047 case SystemZ::BI__builtin_s390_vfaezbs: 1048 case SystemZ::BI__builtin_s390_vfaezhs: 1049 case SystemZ::BI__builtin_s390_vfaezfs: i = 2; l = 0; u = 15; break; 1050 case SystemZ::BI__builtin_s390_vfidb: 1051 return SemaBuiltinConstantArgRange(TheCall, 1, 0, 15) || 1052 SemaBuiltinConstantArgRange(TheCall, 2, 0, 15); 1053 case SystemZ::BI__builtin_s390_vftcidb: i = 1; l = 0; u = 4095; break; 1054 case SystemZ::BI__builtin_s390_vlbb: i = 1; l = 0; u = 15; break; 1055 case SystemZ::BI__builtin_s390_vpdi: i = 2; l = 0; u = 15; break; 1056 case SystemZ::BI__builtin_s390_vsldb: i = 2; l = 0; u = 15; break; 1057 case SystemZ::BI__builtin_s390_vstrcb: 1058 case SystemZ::BI__builtin_s390_vstrch: 1059 case SystemZ::BI__builtin_s390_vstrcf: 1060 case SystemZ::BI__builtin_s390_vstrczb: 1061 case SystemZ::BI__builtin_s390_vstrczh: 1062 case SystemZ::BI__builtin_s390_vstrczf: 1063 case SystemZ::BI__builtin_s390_vstrcbs: 1064 case SystemZ::BI__builtin_s390_vstrchs: 1065 case SystemZ::BI__builtin_s390_vstrcfs: 1066 case SystemZ::BI__builtin_s390_vstrczbs: 1067 case SystemZ::BI__builtin_s390_vstrczhs: 1068 case SystemZ::BI__builtin_s390_vstrczfs: i = 3; l = 0; u = 15; break; 1069 } 1070 return SemaBuiltinConstantArgRange(TheCall, i, l, u); 1071 } 1072 1073 bool Sema::CheckX86BuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) { 1074 unsigned i = 0, l = 0, u = 0; 1075 switch (BuiltinID) { 1076 default: return false; 1077 case X86::BI__builtin_cpu_supports: 1078 return SemaBuiltinCpuSupports(TheCall); 1079 case X86::BI__builtin_ms_va_start: 1080 return SemaBuiltinMSVAStart(TheCall); 1081 case X86::BI_mm_prefetch: i = 1; l = 0; u = 3; break; 1082 case X86::BI__builtin_ia32_sha1rnds4: i = 2, l = 0; u = 3; break; 1083 case X86::BI__builtin_ia32_vpermil2pd: 1084 case X86::BI__builtin_ia32_vpermil2pd256: 1085 case X86::BI__builtin_ia32_vpermil2ps: 1086 case X86::BI__builtin_ia32_vpermil2ps256: i = 3, l = 0; u = 3; break; 1087 case X86::BI__builtin_ia32_cmpb128_mask: 1088 case X86::BI__builtin_ia32_cmpw128_mask: 1089 case X86::BI__builtin_ia32_cmpd128_mask: 1090 case X86::BI__builtin_ia32_cmpq128_mask: 1091 case X86::BI__builtin_ia32_cmpb256_mask: 1092 case X86::BI__builtin_ia32_cmpw256_mask: 1093 case X86::BI__builtin_ia32_cmpd256_mask: 1094 case X86::BI__builtin_ia32_cmpq256_mask: 1095 case X86::BI__builtin_ia32_cmpb512_mask: 1096 case X86::BI__builtin_ia32_cmpw512_mask: 1097 case X86::BI__builtin_ia32_cmpd512_mask: 1098 case X86::BI__builtin_ia32_cmpq512_mask: 1099 case X86::BI__builtin_ia32_ucmpb128_mask: 1100 case X86::BI__builtin_ia32_ucmpw128_mask: 1101 case X86::BI__builtin_ia32_ucmpd128_mask: 1102 case X86::BI__builtin_ia32_ucmpq128_mask: 1103 case X86::BI__builtin_ia32_ucmpb256_mask: 1104 case X86::BI__builtin_ia32_ucmpw256_mask: 1105 case X86::BI__builtin_ia32_ucmpd256_mask: 1106 case X86::BI__builtin_ia32_ucmpq256_mask: 1107 case X86::BI__builtin_ia32_ucmpb512_mask: 1108 case X86::BI__builtin_ia32_ucmpw512_mask: 1109 case X86::BI__builtin_ia32_ucmpd512_mask: 1110 case X86::BI__builtin_ia32_ucmpq512_mask: i = 2; l = 0; u = 7; break; 1111 case X86::BI__builtin_ia32_roundps: 1112 case X86::BI__builtin_ia32_roundpd: 1113 case X86::BI__builtin_ia32_roundps256: 1114 case X86::BI__builtin_ia32_roundpd256: i = 1, l = 0; u = 15; break; 1115 case X86::BI__builtin_ia32_roundss: 1116 case X86::BI__builtin_ia32_roundsd: i = 2, l = 0; u = 15; break; 1117 case X86::BI__builtin_ia32_cmpps: 1118 case X86::BI__builtin_ia32_cmpss: 1119 case X86::BI__builtin_ia32_cmppd: 1120 case X86::BI__builtin_ia32_cmpsd: 1121 case X86::BI__builtin_ia32_cmpps256: 1122 case X86::BI__builtin_ia32_cmppd256: 1123 case X86::BI__builtin_ia32_cmpps512_mask: 1124 case X86::BI__builtin_ia32_cmppd512_mask: i = 2; l = 0; u = 31; break; 1125 case X86::BI__builtin_ia32_vpcomub: 1126 case X86::BI__builtin_ia32_vpcomuw: 1127 case X86::BI__builtin_ia32_vpcomud: 1128 case X86::BI__builtin_ia32_vpcomuq: 1129 case X86::BI__builtin_ia32_vpcomb: 1130 case X86::BI__builtin_ia32_vpcomw: 1131 case X86::BI__builtin_ia32_vpcomd: 1132 case X86::BI__builtin_ia32_vpcomq: i = 2; l = 0; u = 7; break; 1133 } 1134 return SemaBuiltinConstantArgRange(TheCall, i, l, u); 1135 } 1136 1137 /// Given a FunctionDecl's FormatAttr, attempts to populate the FomatStringInfo 1138 /// parameter with the FormatAttr's correct format_idx and firstDataArg. 1139 /// Returns true when the format fits the function and the FormatStringInfo has 1140 /// been populated. 1141 bool Sema::getFormatStringInfo(const FormatAttr *Format, bool IsCXXMember, 1142 FormatStringInfo *FSI) { 1143 FSI->HasVAListArg = Format->getFirstArg() == 0; 1144 FSI->FormatIdx = Format->getFormatIdx() - 1; 1145 FSI->FirstDataArg = FSI->HasVAListArg ? 0 : Format->getFirstArg() - 1; 1146 1147 // The way the format attribute works in GCC, the implicit this argument 1148 // of member functions is counted. However, it doesn't appear in our own 1149 // lists, so decrement format_idx in that case. 1150 if (IsCXXMember) { 1151 if(FSI->FormatIdx == 0) 1152 return false; 1153 --FSI->FormatIdx; 1154 if (FSI->FirstDataArg != 0) 1155 --FSI->FirstDataArg; 1156 } 1157 return true; 1158 } 1159 1160 /// Checks if a the given expression evaluates to null. 1161 /// 1162 /// \brief Returns true if the value evaluates to null. 1163 static bool CheckNonNullExpr(Sema &S, 1164 const Expr *Expr) { 1165 // If the expression has non-null type, it doesn't evaluate to null. 1166 if (auto nullability 1167 = Expr->IgnoreImplicit()->getType()->getNullability(S.Context)) { 1168 if (*nullability == NullabilityKind::NonNull) 1169 return false; 1170 } 1171 1172 // As a special case, transparent unions initialized with zero are 1173 // considered null for the purposes of the nonnull attribute. 1174 if (const RecordType *UT = Expr->getType()->getAsUnionType()) { 1175 if (UT->getDecl()->hasAttr<TransparentUnionAttr>()) 1176 if (const CompoundLiteralExpr *CLE = 1177 dyn_cast<CompoundLiteralExpr>(Expr)) 1178 if (const InitListExpr *ILE = 1179 dyn_cast<InitListExpr>(CLE->getInitializer())) 1180 Expr = ILE->getInit(0); 1181 } 1182 1183 bool Result; 1184 return (!Expr->isValueDependent() && 1185 Expr->EvaluateAsBooleanCondition(Result, S.Context) && 1186 !Result); 1187 } 1188 1189 static void CheckNonNullArgument(Sema &S, 1190 const Expr *ArgExpr, 1191 SourceLocation CallSiteLoc) { 1192 if (CheckNonNullExpr(S, ArgExpr)) 1193 S.DiagRuntimeBehavior(CallSiteLoc, ArgExpr, 1194 S.PDiag(diag::warn_null_arg) << ArgExpr->getSourceRange()); 1195 } 1196 1197 bool Sema::GetFormatNSStringIdx(const FormatAttr *Format, unsigned &Idx) { 1198 FormatStringInfo FSI; 1199 if ((GetFormatStringType(Format) == FST_NSString) && 1200 getFormatStringInfo(Format, false, &FSI)) { 1201 Idx = FSI.FormatIdx; 1202 return true; 1203 } 1204 return false; 1205 } 1206 /// \brief Diagnose use of %s directive in an NSString which is being passed 1207 /// as formatting string to formatting method. 1208 static void 1209 DiagnoseCStringFormatDirectiveInCFAPI(Sema &S, 1210 const NamedDecl *FDecl, 1211 Expr **Args, 1212 unsigned NumArgs) { 1213 unsigned Idx = 0; 1214 bool Format = false; 1215 ObjCStringFormatFamily SFFamily = FDecl->getObjCFStringFormattingFamily(); 1216 if (SFFamily == ObjCStringFormatFamily::SFF_CFString) { 1217 Idx = 2; 1218 Format = true; 1219 } 1220 else 1221 for (const auto *I : FDecl->specific_attrs<FormatAttr>()) { 1222 if (S.GetFormatNSStringIdx(I, Idx)) { 1223 Format = true; 1224 break; 1225 } 1226 } 1227 if (!Format || NumArgs <= Idx) 1228 return; 1229 const Expr *FormatExpr = Args[Idx]; 1230 if (const CStyleCastExpr *CSCE = dyn_cast<CStyleCastExpr>(FormatExpr)) 1231 FormatExpr = CSCE->getSubExpr(); 1232 const StringLiteral *FormatString; 1233 if (const ObjCStringLiteral *OSL = 1234 dyn_cast<ObjCStringLiteral>(FormatExpr->IgnoreParenImpCasts())) 1235 FormatString = OSL->getString(); 1236 else 1237 FormatString = dyn_cast<StringLiteral>(FormatExpr->IgnoreParenImpCasts()); 1238 if (!FormatString) 1239 return; 1240 if (S.FormatStringHasSArg(FormatString)) { 1241 S.Diag(FormatExpr->getExprLoc(), diag::warn_objc_cdirective_format_string) 1242 << "%s" << 1 << 1; 1243 S.Diag(FDecl->getLocation(), diag::note_entity_declared_at) 1244 << FDecl->getDeclName(); 1245 } 1246 } 1247 1248 /// Determine whether the given type has a non-null nullability annotation. 1249 static bool isNonNullType(ASTContext &ctx, QualType type) { 1250 if (auto nullability = type->getNullability(ctx)) 1251 return *nullability == NullabilityKind::NonNull; 1252 1253 return false; 1254 } 1255 1256 static void CheckNonNullArguments(Sema &S, 1257 const NamedDecl *FDecl, 1258 const FunctionProtoType *Proto, 1259 ArrayRef<const Expr *> Args, 1260 SourceLocation CallSiteLoc) { 1261 assert((FDecl || Proto) && "Need a function declaration or prototype"); 1262 1263 // Check the attributes attached to the method/function itself. 1264 llvm::SmallBitVector NonNullArgs; 1265 if (FDecl) { 1266 // Handle the nonnull attribute on the function/method declaration itself. 1267 for (const auto *NonNull : FDecl->specific_attrs<NonNullAttr>()) { 1268 if (!NonNull->args_size()) { 1269 // Easy case: all pointer arguments are nonnull. 1270 for (const auto *Arg : Args) 1271 if (S.isValidPointerAttrType(Arg->getType())) 1272 CheckNonNullArgument(S, Arg, CallSiteLoc); 1273 return; 1274 } 1275 1276 for (unsigned Val : NonNull->args()) { 1277 if (Val >= Args.size()) 1278 continue; 1279 if (NonNullArgs.empty()) 1280 NonNullArgs.resize(Args.size()); 1281 NonNullArgs.set(Val); 1282 } 1283 } 1284 } 1285 1286 if (FDecl && (isa<FunctionDecl>(FDecl) || isa<ObjCMethodDecl>(FDecl))) { 1287 // Handle the nonnull attribute on the parameters of the 1288 // function/method. 1289 ArrayRef<ParmVarDecl*> parms; 1290 if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(FDecl)) 1291 parms = FD->parameters(); 1292 else 1293 parms = cast<ObjCMethodDecl>(FDecl)->parameters(); 1294 1295 unsigned ParamIndex = 0; 1296 for (ArrayRef<ParmVarDecl*>::iterator I = parms.begin(), E = parms.end(); 1297 I != E; ++I, ++ParamIndex) { 1298 const ParmVarDecl *PVD = *I; 1299 if (PVD->hasAttr<NonNullAttr>() || 1300 isNonNullType(S.Context, PVD->getType())) { 1301 if (NonNullArgs.empty()) 1302 NonNullArgs.resize(Args.size()); 1303 1304 NonNullArgs.set(ParamIndex); 1305 } 1306 } 1307 } else { 1308 // If we have a non-function, non-method declaration but no 1309 // function prototype, try to dig out the function prototype. 1310 if (!Proto) { 1311 if (const ValueDecl *VD = dyn_cast<ValueDecl>(FDecl)) { 1312 QualType type = VD->getType().getNonReferenceType(); 1313 if (auto pointerType = type->getAs<PointerType>()) 1314 type = pointerType->getPointeeType(); 1315 else if (auto blockType = type->getAs<BlockPointerType>()) 1316 type = blockType->getPointeeType(); 1317 // FIXME: data member pointers? 1318 1319 // Dig out the function prototype, if there is one. 1320 Proto = type->getAs<FunctionProtoType>(); 1321 } 1322 } 1323 1324 // Fill in non-null argument information from the nullability 1325 // information on the parameter types (if we have them). 1326 if (Proto) { 1327 unsigned Index = 0; 1328 for (auto paramType : Proto->getParamTypes()) { 1329 if (isNonNullType(S.Context, paramType)) { 1330 if (NonNullArgs.empty()) 1331 NonNullArgs.resize(Args.size()); 1332 1333 NonNullArgs.set(Index); 1334 } 1335 1336 ++Index; 1337 } 1338 } 1339 } 1340 1341 // Check for non-null arguments. 1342 for (unsigned ArgIndex = 0, ArgIndexEnd = NonNullArgs.size(); 1343 ArgIndex != ArgIndexEnd; ++ArgIndex) { 1344 if (NonNullArgs[ArgIndex]) 1345 CheckNonNullArgument(S, Args[ArgIndex], CallSiteLoc); 1346 } 1347 } 1348 1349 /// Handles the checks for format strings, non-POD arguments to vararg 1350 /// functions, and NULL arguments passed to non-NULL parameters. 1351 void Sema::checkCall(NamedDecl *FDecl, const FunctionProtoType *Proto, 1352 ArrayRef<const Expr *> Args, bool IsMemberFunction, 1353 SourceLocation Loc, SourceRange Range, 1354 VariadicCallType CallType) { 1355 // FIXME: We should check as much as we can in the template definition. 1356 if (CurContext->isDependentContext()) 1357 return; 1358 1359 // Printf and scanf checking. 1360 llvm::SmallBitVector CheckedVarArgs; 1361 if (FDecl) { 1362 for (const auto *I : FDecl->specific_attrs<FormatAttr>()) { 1363 // Only create vector if there are format attributes. 1364 CheckedVarArgs.resize(Args.size()); 1365 1366 CheckFormatArguments(I, Args, IsMemberFunction, CallType, Loc, Range, 1367 CheckedVarArgs); 1368 } 1369 } 1370 1371 // Refuse POD arguments that weren't caught by the format string 1372 // checks above. 1373 if (CallType != VariadicDoesNotApply) { 1374 unsigned NumParams = Proto ? Proto->getNumParams() 1375 : FDecl && isa<FunctionDecl>(FDecl) 1376 ? cast<FunctionDecl>(FDecl)->getNumParams() 1377 : FDecl && isa<ObjCMethodDecl>(FDecl) 1378 ? cast<ObjCMethodDecl>(FDecl)->param_size() 1379 : 0; 1380 1381 for (unsigned ArgIdx = NumParams; ArgIdx < Args.size(); ++ArgIdx) { 1382 // Args[ArgIdx] can be null in malformed code. 1383 if (const Expr *Arg = Args[ArgIdx]) { 1384 if (CheckedVarArgs.empty() || !CheckedVarArgs[ArgIdx]) 1385 checkVariadicArgument(Arg, CallType); 1386 } 1387 } 1388 } 1389 1390 if (FDecl || Proto) { 1391 CheckNonNullArguments(*this, FDecl, Proto, Args, Loc); 1392 1393 // Type safety checking. 1394 if (FDecl) { 1395 for (const auto *I : FDecl->specific_attrs<ArgumentWithTypeTagAttr>()) 1396 CheckArgumentWithTypeTag(I, Args.data()); 1397 } 1398 } 1399 } 1400 1401 /// CheckConstructorCall - Check a constructor call for correctness and safety 1402 /// properties not enforced by the C type system. 1403 void Sema::CheckConstructorCall(FunctionDecl *FDecl, 1404 ArrayRef<const Expr *> Args, 1405 const FunctionProtoType *Proto, 1406 SourceLocation Loc) { 1407 VariadicCallType CallType = 1408 Proto->isVariadic() ? VariadicConstructor : VariadicDoesNotApply; 1409 checkCall(FDecl, Proto, Args, /*IsMemberFunction=*/true, Loc, SourceRange(), 1410 CallType); 1411 } 1412 1413 /// CheckFunctionCall - Check a direct function call for various correctness 1414 /// and safety properties not strictly enforced by the C type system. 1415 bool Sema::CheckFunctionCall(FunctionDecl *FDecl, CallExpr *TheCall, 1416 const FunctionProtoType *Proto) { 1417 bool IsMemberOperatorCall = isa<CXXOperatorCallExpr>(TheCall) && 1418 isa<CXXMethodDecl>(FDecl); 1419 bool IsMemberFunction = isa<CXXMemberCallExpr>(TheCall) || 1420 IsMemberOperatorCall; 1421 VariadicCallType CallType = getVariadicCallType(FDecl, Proto, 1422 TheCall->getCallee()); 1423 Expr** Args = TheCall->getArgs(); 1424 unsigned NumArgs = TheCall->getNumArgs(); 1425 if (IsMemberOperatorCall) { 1426 // If this is a call to a member operator, hide the first argument 1427 // from checkCall. 1428 // FIXME: Our choice of AST representation here is less than ideal. 1429 ++Args; 1430 --NumArgs; 1431 } 1432 checkCall(FDecl, Proto, llvm::makeArrayRef(Args, NumArgs), 1433 IsMemberFunction, TheCall->getRParenLoc(), 1434 TheCall->getCallee()->getSourceRange(), CallType); 1435 1436 IdentifierInfo *FnInfo = FDecl->getIdentifier(); 1437 // None of the checks below are needed for functions that don't have 1438 // simple names (e.g., C++ conversion functions). 1439 if (!FnInfo) 1440 return false; 1441 1442 CheckAbsoluteValueFunction(TheCall, FDecl, FnInfo); 1443 if (getLangOpts().ObjC1) 1444 DiagnoseCStringFormatDirectiveInCFAPI(*this, FDecl, Args, NumArgs); 1445 1446 unsigned CMId = FDecl->getMemoryFunctionKind(); 1447 if (CMId == 0) 1448 return false; 1449 1450 // Handle memory setting and copying functions. 1451 if (CMId == Builtin::BIstrlcpy || CMId == Builtin::BIstrlcat) 1452 CheckStrlcpycatArguments(TheCall, FnInfo); 1453 else if (CMId == Builtin::BIstrncat) 1454 CheckStrncatArguments(TheCall, FnInfo); 1455 else 1456 CheckMemaccessArguments(TheCall, CMId, FnInfo); 1457 1458 return false; 1459 } 1460 1461 bool Sema::CheckObjCMethodCall(ObjCMethodDecl *Method, SourceLocation lbrac, 1462 ArrayRef<const Expr *> Args) { 1463 VariadicCallType CallType = 1464 Method->isVariadic() ? VariadicMethod : VariadicDoesNotApply; 1465 1466 checkCall(Method, nullptr, Args, 1467 /*IsMemberFunction=*/false, lbrac, Method->getSourceRange(), 1468 CallType); 1469 1470 return false; 1471 } 1472 1473 bool Sema::CheckPointerCall(NamedDecl *NDecl, CallExpr *TheCall, 1474 const FunctionProtoType *Proto) { 1475 QualType Ty; 1476 if (const auto *V = dyn_cast<VarDecl>(NDecl)) 1477 Ty = V->getType().getNonReferenceType(); 1478 else if (const auto *F = dyn_cast<FieldDecl>(NDecl)) 1479 Ty = F->getType().getNonReferenceType(); 1480 else 1481 return false; 1482 1483 if (!Ty->isBlockPointerType() && !Ty->isFunctionPointerType() && 1484 !Ty->isFunctionProtoType()) 1485 return false; 1486 1487 VariadicCallType CallType; 1488 if (!Proto || !Proto->isVariadic()) { 1489 CallType = VariadicDoesNotApply; 1490 } else if (Ty->isBlockPointerType()) { 1491 CallType = VariadicBlock; 1492 } else { // Ty->isFunctionPointerType() 1493 CallType = VariadicFunction; 1494 } 1495 1496 checkCall(NDecl, Proto, 1497 llvm::makeArrayRef(TheCall->getArgs(), TheCall->getNumArgs()), 1498 /*IsMemberFunction=*/false, TheCall->getRParenLoc(), 1499 TheCall->getCallee()->getSourceRange(), CallType); 1500 1501 return false; 1502 } 1503 1504 /// Checks function calls when a FunctionDecl or a NamedDecl is not available, 1505 /// such as function pointers returned from functions. 1506 bool Sema::CheckOtherCall(CallExpr *TheCall, const FunctionProtoType *Proto) { 1507 VariadicCallType CallType = getVariadicCallType(/*FDecl=*/nullptr, Proto, 1508 TheCall->getCallee()); 1509 checkCall(/*FDecl=*/nullptr, Proto, 1510 llvm::makeArrayRef(TheCall->getArgs(), TheCall->getNumArgs()), 1511 /*IsMemberFunction=*/false, TheCall->getRParenLoc(), 1512 TheCall->getCallee()->getSourceRange(), CallType); 1513 1514 return false; 1515 } 1516 1517 static bool isValidOrderingForOp(int64_t Ordering, AtomicExpr::AtomicOp Op) { 1518 if (Ordering < AtomicExpr::AO_ABI_memory_order_relaxed || 1519 Ordering > AtomicExpr::AO_ABI_memory_order_seq_cst) 1520 return false; 1521 1522 switch (Op) { 1523 case AtomicExpr::AO__c11_atomic_init: 1524 llvm_unreachable("There is no ordering argument for an init"); 1525 1526 case AtomicExpr::AO__c11_atomic_load: 1527 case AtomicExpr::AO__atomic_load_n: 1528 case AtomicExpr::AO__atomic_load: 1529 return Ordering != AtomicExpr::AO_ABI_memory_order_release && 1530 Ordering != AtomicExpr::AO_ABI_memory_order_acq_rel; 1531 1532 case AtomicExpr::AO__c11_atomic_store: 1533 case AtomicExpr::AO__atomic_store: 1534 case AtomicExpr::AO__atomic_store_n: 1535 return Ordering != AtomicExpr::AO_ABI_memory_order_consume && 1536 Ordering != AtomicExpr::AO_ABI_memory_order_acquire && 1537 Ordering != AtomicExpr::AO_ABI_memory_order_acq_rel; 1538 1539 default: 1540 return true; 1541 } 1542 } 1543 1544 ExprResult Sema::SemaAtomicOpsOverloaded(ExprResult TheCallResult, 1545 AtomicExpr::AtomicOp Op) { 1546 CallExpr *TheCall = cast<CallExpr>(TheCallResult.get()); 1547 DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts()); 1548 1549 // All these operations take one of the following forms: 1550 enum { 1551 // C __c11_atomic_init(A *, C) 1552 Init, 1553 // C __c11_atomic_load(A *, int) 1554 Load, 1555 // void __atomic_load(A *, CP, int) 1556 Copy, 1557 // C __c11_atomic_add(A *, M, int) 1558 Arithmetic, 1559 // C __atomic_exchange_n(A *, CP, int) 1560 Xchg, 1561 // void __atomic_exchange(A *, C *, CP, int) 1562 GNUXchg, 1563 // bool __c11_atomic_compare_exchange_strong(A *, C *, CP, int, int) 1564 C11CmpXchg, 1565 // bool __atomic_compare_exchange(A *, C *, CP, bool, int, int) 1566 GNUCmpXchg 1567 } Form = Init; 1568 const unsigned NumArgs[] = { 2, 2, 3, 3, 3, 4, 5, 6 }; 1569 const unsigned NumVals[] = { 1, 0, 1, 1, 1, 2, 2, 3 }; 1570 // where: 1571 // C is an appropriate type, 1572 // A is volatile _Atomic(C) for __c11 builtins and is C for GNU builtins, 1573 // CP is C for __c11 builtins and GNU _n builtins and is C * otherwise, 1574 // M is C if C is an integer, and ptrdiff_t if C is a pointer, and 1575 // the int parameters are for orderings. 1576 1577 static_assert(AtomicExpr::AO__c11_atomic_init == 0 && 1578 AtomicExpr::AO__c11_atomic_fetch_xor + 1 == 1579 AtomicExpr::AO__atomic_load, 1580 "need to update code for modified C11 atomics"); 1581 bool IsC11 = Op >= AtomicExpr::AO__c11_atomic_init && 1582 Op <= AtomicExpr::AO__c11_atomic_fetch_xor; 1583 bool IsN = Op == AtomicExpr::AO__atomic_load_n || 1584 Op == AtomicExpr::AO__atomic_store_n || 1585 Op == AtomicExpr::AO__atomic_exchange_n || 1586 Op == AtomicExpr::AO__atomic_compare_exchange_n; 1587 bool IsAddSub = false; 1588 1589 switch (Op) { 1590 case AtomicExpr::AO__c11_atomic_init: 1591 Form = Init; 1592 break; 1593 1594 case AtomicExpr::AO__c11_atomic_load: 1595 case AtomicExpr::AO__atomic_load_n: 1596 Form = Load; 1597 break; 1598 1599 case AtomicExpr::AO__c11_atomic_store: 1600 case AtomicExpr::AO__atomic_load: 1601 case AtomicExpr::AO__atomic_store: 1602 case AtomicExpr::AO__atomic_store_n: 1603 Form = Copy; 1604 break; 1605 1606 case AtomicExpr::AO__c11_atomic_fetch_add: 1607 case AtomicExpr::AO__c11_atomic_fetch_sub: 1608 case AtomicExpr::AO__atomic_fetch_add: 1609 case AtomicExpr::AO__atomic_fetch_sub: 1610 case AtomicExpr::AO__atomic_add_fetch: 1611 case AtomicExpr::AO__atomic_sub_fetch: 1612 IsAddSub = true; 1613 // Fall through. 1614 case AtomicExpr::AO__c11_atomic_fetch_and: 1615 case AtomicExpr::AO__c11_atomic_fetch_or: 1616 case AtomicExpr::AO__c11_atomic_fetch_xor: 1617 case AtomicExpr::AO__atomic_fetch_and: 1618 case AtomicExpr::AO__atomic_fetch_or: 1619 case AtomicExpr::AO__atomic_fetch_xor: 1620 case AtomicExpr::AO__atomic_fetch_nand: 1621 case AtomicExpr::AO__atomic_and_fetch: 1622 case AtomicExpr::AO__atomic_or_fetch: 1623 case AtomicExpr::AO__atomic_xor_fetch: 1624 case AtomicExpr::AO__atomic_nand_fetch: 1625 Form = Arithmetic; 1626 break; 1627 1628 case AtomicExpr::AO__c11_atomic_exchange: 1629 case AtomicExpr::AO__atomic_exchange_n: 1630 Form = Xchg; 1631 break; 1632 1633 case AtomicExpr::AO__atomic_exchange: 1634 Form = GNUXchg; 1635 break; 1636 1637 case AtomicExpr::AO__c11_atomic_compare_exchange_strong: 1638 case AtomicExpr::AO__c11_atomic_compare_exchange_weak: 1639 Form = C11CmpXchg; 1640 break; 1641 1642 case AtomicExpr::AO__atomic_compare_exchange: 1643 case AtomicExpr::AO__atomic_compare_exchange_n: 1644 Form = GNUCmpXchg; 1645 break; 1646 } 1647 1648 // Check we have the right number of arguments. 1649 if (TheCall->getNumArgs() < NumArgs[Form]) { 1650 Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args) 1651 << 0 << NumArgs[Form] << TheCall->getNumArgs() 1652 << TheCall->getCallee()->getSourceRange(); 1653 return ExprError(); 1654 } else if (TheCall->getNumArgs() > NumArgs[Form]) { 1655 Diag(TheCall->getArg(NumArgs[Form])->getLocStart(), 1656 diag::err_typecheck_call_too_many_args) 1657 << 0 << NumArgs[Form] << TheCall->getNumArgs() 1658 << TheCall->getCallee()->getSourceRange(); 1659 return ExprError(); 1660 } 1661 1662 // Inspect the first argument of the atomic operation. 1663 Expr *Ptr = TheCall->getArg(0); 1664 Ptr = DefaultFunctionArrayLvalueConversion(Ptr).get(); 1665 const PointerType *pointerType = Ptr->getType()->getAs<PointerType>(); 1666 if (!pointerType) { 1667 Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer) 1668 << Ptr->getType() << Ptr->getSourceRange(); 1669 return ExprError(); 1670 } 1671 1672 // For a __c11 builtin, this should be a pointer to an _Atomic type. 1673 QualType AtomTy = pointerType->getPointeeType(); // 'A' 1674 QualType ValType = AtomTy; // 'C' 1675 if (IsC11) { 1676 if (!AtomTy->isAtomicType()) { 1677 Diag(DRE->getLocStart(), diag::err_atomic_op_needs_atomic) 1678 << Ptr->getType() << Ptr->getSourceRange(); 1679 return ExprError(); 1680 } 1681 if (AtomTy.isConstQualified()) { 1682 Diag(DRE->getLocStart(), diag::err_atomic_op_needs_non_const_atomic) 1683 << Ptr->getType() << Ptr->getSourceRange(); 1684 return ExprError(); 1685 } 1686 ValType = AtomTy->getAs<AtomicType>()->getValueType(); 1687 } else if (Form != Load && Op != AtomicExpr::AO__atomic_load) { 1688 if (ValType.isConstQualified()) { 1689 Diag(DRE->getLocStart(), diag::err_atomic_op_needs_non_const_pointer) 1690 << Ptr->getType() << Ptr->getSourceRange(); 1691 return ExprError(); 1692 } 1693 } 1694 1695 // For an arithmetic operation, the implied arithmetic must be well-formed. 1696 if (Form == Arithmetic) { 1697 // gcc does not enforce these rules for GNU atomics, but we do so for sanity. 1698 if (IsAddSub && !ValType->isIntegerType() && !ValType->isPointerType()) { 1699 Diag(DRE->getLocStart(), diag::err_atomic_op_needs_atomic_int_or_ptr) 1700 << IsC11 << Ptr->getType() << Ptr->getSourceRange(); 1701 return ExprError(); 1702 } 1703 if (!IsAddSub && !ValType->isIntegerType()) { 1704 Diag(DRE->getLocStart(), diag::err_atomic_op_bitwise_needs_atomic_int) 1705 << IsC11 << Ptr->getType() << Ptr->getSourceRange(); 1706 return ExprError(); 1707 } 1708 if (IsC11 && ValType->isPointerType() && 1709 RequireCompleteType(Ptr->getLocStart(), ValType->getPointeeType(), 1710 diag::err_incomplete_type)) { 1711 return ExprError(); 1712 } 1713 } else if (IsN && !ValType->isIntegerType() && !ValType->isPointerType()) { 1714 // For __atomic_*_n operations, the value type must be a scalar integral or 1715 // pointer type which is 1, 2, 4, 8 or 16 bytes in length. 1716 Diag(DRE->getLocStart(), diag::err_atomic_op_needs_atomic_int_or_ptr) 1717 << IsC11 << Ptr->getType() << Ptr->getSourceRange(); 1718 return ExprError(); 1719 } 1720 1721 if (!IsC11 && !AtomTy.isTriviallyCopyableType(Context) && 1722 !AtomTy->isScalarType()) { 1723 // For GNU atomics, require a trivially-copyable type. This is not part of 1724 // the GNU atomics specification, but we enforce it for sanity. 1725 Diag(DRE->getLocStart(), diag::err_atomic_op_needs_trivial_copy) 1726 << Ptr->getType() << Ptr->getSourceRange(); 1727 return ExprError(); 1728 } 1729 1730 switch (ValType.getObjCLifetime()) { 1731 case Qualifiers::OCL_None: 1732 case Qualifiers::OCL_ExplicitNone: 1733 // okay 1734 break; 1735 1736 case Qualifiers::OCL_Weak: 1737 case Qualifiers::OCL_Strong: 1738 case Qualifiers::OCL_Autoreleasing: 1739 // FIXME: Can this happen? By this point, ValType should be known 1740 // to be trivially copyable. 1741 Diag(DRE->getLocStart(), diag::err_arc_atomic_ownership) 1742 << ValType << Ptr->getSourceRange(); 1743 return ExprError(); 1744 } 1745 1746 // atomic_fetch_or takes a pointer to a volatile 'A'. We shouldn't let the 1747 // volatile-ness of the pointee-type inject itself into the result or the 1748 // other operands. 1749 ValType.removeLocalVolatile(); 1750 QualType ResultType = ValType; 1751 if (Form == Copy || Form == GNUXchg || Form == Init) 1752 ResultType = Context.VoidTy; 1753 else if (Form == C11CmpXchg || Form == GNUCmpXchg) 1754 ResultType = Context.BoolTy; 1755 1756 // The type of a parameter passed 'by value'. In the GNU atomics, such 1757 // arguments are actually passed as pointers. 1758 QualType ByValType = ValType; // 'CP' 1759 if (!IsC11 && !IsN) 1760 ByValType = Ptr->getType(); 1761 1762 // FIXME: __atomic_load allows the first argument to be a a pointer to const 1763 // but not the second argument. We need to manually remove possible const 1764 // qualifiers. 1765 1766 // The first argument --- the pointer --- has a fixed type; we 1767 // deduce the types of the rest of the arguments accordingly. Walk 1768 // the remaining arguments, converting them to the deduced value type. 1769 for (unsigned i = 1; i != NumArgs[Form]; ++i) { 1770 QualType Ty; 1771 if (i < NumVals[Form] + 1) { 1772 switch (i) { 1773 case 1: 1774 // The second argument is the non-atomic operand. For arithmetic, this 1775 // is always passed by value, and for a compare_exchange it is always 1776 // passed by address. For the rest, GNU uses by-address and C11 uses 1777 // by-value. 1778 assert(Form != Load); 1779 if (Form == Init || (Form == Arithmetic && ValType->isIntegerType())) 1780 Ty = ValType; 1781 else if (Form == Copy || Form == Xchg) 1782 Ty = ByValType; 1783 else if (Form == Arithmetic) 1784 Ty = Context.getPointerDiffType(); 1785 else 1786 Ty = Context.getPointerType(ValType.getUnqualifiedType()); 1787 break; 1788 case 2: 1789 // The third argument to compare_exchange / GNU exchange is a 1790 // (pointer to a) desired value. 1791 Ty = ByValType; 1792 break; 1793 case 3: 1794 // The fourth argument to GNU compare_exchange is a 'weak' flag. 1795 Ty = Context.BoolTy; 1796 break; 1797 } 1798 } else { 1799 // The order(s) are always converted to int. 1800 Ty = Context.IntTy; 1801 } 1802 1803 InitializedEntity Entity = 1804 InitializedEntity::InitializeParameter(Context, Ty, false); 1805 ExprResult Arg = TheCall->getArg(i); 1806 Arg = PerformCopyInitialization(Entity, SourceLocation(), Arg); 1807 if (Arg.isInvalid()) 1808 return true; 1809 TheCall->setArg(i, Arg.get()); 1810 } 1811 1812 // Permute the arguments into a 'consistent' order. 1813 SmallVector<Expr*, 5> SubExprs; 1814 SubExprs.push_back(Ptr); 1815 switch (Form) { 1816 case Init: 1817 // Note, AtomicExpr::getVal1() has a special case for this atomic. 1818 SubExprs.push_back(TheCall->getArg(1)); // Val1 1819 break; 1820 case Load: 1821 SubExprs.push_back(TheCall->getArg(1)); // Order 1822 break; 1823 case Copy: 1824 case Arithmetic: 1825 case Xchg: 1826 SubExprs.push_back(TheCall->getArg(2)); // Order 1827 SubExprs.push_back(TheCall->getArg(1)); // Val1 1828 break; 1829 case GNUXchg: 1830 // Note, AtomicExpr::getVal2() has a special case for this atomic. 1831 SubExprs.push_back(TheCall->getArg(3)); // Order 1832 SubExprs.push_back(TheCall->getArg(1)); // Val1 1833 SubExprs.push_back(TheCall->getArg(2)); // Val2 1834 break; 1835 case C11CmpXchg: 1836 SubExprs.push_back(TheCall->getArg(3)); // Order 1837 SubExprs.push_back(TheCall->getArg(1)); // Val1 1838 SubExprs.push_back(TheCall->getArg(4)); // OrderFail 1839 SubExprs.push_back(TheCall->getArg(2)); // Val2 1840 break; 1841 case GNUCmpXchg: 1842 SubExprs.push_back(TheCall->getArg(4)); // Order 1843 SubExprs.push_back(TheCall->getArg(1)); // Val1 1844 SubExprs.push_back(TheCall->getArg(5)); // OrderFail 1845 SubExprs.push_back(TheCall->getArg(2)); // Val2 1846 SubExprs.push_back(TheCall->getArg(3)); // Weak 1847 break; 1848 } 1849 1850 if (SubExprs.size() >= 2 && Form != Init) { 1851 llvm::APSInt Result(32); 1852 if (SubExprs[1]->isIntegerConstantExpr(Result, Context) && 1853 !isValidOrderingForOp(Result.getSExtValue(), Op)) 1854 Diag(SubExprs[1]->getLocStart(), 1855 diag::warn_atomic_op_has_invalid_memory_order) 1856 << SubExprs[1]->getSourceRange(); 1857 } 1858 1859 AtomicExpr *AE = new (Context) AtomicExpr(TheCall->getCallee()->getLocStart(), 1860 SubExprs, ResultType, Op, 1861 TheCall->getRParenLoc()); 1862 1863 if ((Op == AtomicExpr::AO__c11_atomic_load || 1864 (Op == AtomicExpr::AO__c11_atomic_store)) && 1865 Context.AtomicUsesUnsupportedLibcall(AE)) 1866 Diag(AE->getLocStart(), diag::err_atomic_load_store_uses_lib) << 1867 ((Op == AtomicExpr::AO__c11_atomic_load) ? 0 : 1); 1868 1869 return AE; 1870 } 1871 1872 1873 /// checkBuiltinArgument - Given a call to a builtin function, perform 1874 /// normal type-checking on the given argument, updating the call in 1875 /// place. This is useful when a builtin function requires custom 1876 /// type-checking for some of its arguments but not necessarily all of 1877 /// them. 1878 /// 1879 /// Returns true on error. 1880 static bool checkBuiltinArgument(Sema &S, CallExpr *E, unsigned ArgIndex) { 1881 FunctionDecl *Fn = E->getDirectCallee(); 1882 assert(Fn && "builtin call without direct callee!"); 1883 1884 ParmVarDecl *Param = Fn->getParamDecl(ArgIndex); 1885 InitializedEntity Entity = 1886 InitializedEntity::InitializeParameter(S.Context, Param); 1887 1888 ExprResult Arg = E->getArg(0); 1889 Arg = S.PerformCopyInitialization(Entity, SourceLocation(), Arg); 1890 if (Arg.isInvalid()) 1891 return true; 1892 1893 E->setArg(ArgIndex, Arg.get()); 1894 return false; 1895 } 1896 1897 /// SemaBuiltinAtomicOverloaded - We have a call to a function like 1898 /// __sync_fetch_and_add, which is an overloaded function based on the pointer 1899 /// type of its first argument. The main ActOnCallExpr routines have already 1900 /// promoted the types of arguments because all of these calls are prototyped as 1901 /// void(...). 1902 /// 1903 /// This function goes through and does final semantic checking for these 1904 /// builtins, 1905 ExprResult 1906 Sema::SemaBuiltinAtomicOverloaded(ExprResult TheCallResult) { 1907 CallExpr *TheCall = (CallExpr *)TheCallResult.get(); 1908 DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts()); 1909 FunctionDecl *FDecl = cast<FunctionDecl>(DRE->getDecl()); 1910 1911 // Ensure that we have at least one argument to do type inference from. 1912 if (TheCall->getNumArgs() < 1) { 1913 Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args_at_least) 1914 << 0 << 1 << TheCall->getNumArgs() 1915 << TheCall->getCallee()->getSourceRange(); 1916 return ExprError(); 1917 } 1918 1919 // Inspect the first argument of the atomic builtin. This should always be 1920 // a pointer type, whose element is an integral scalar or pointer type. 1921 // Because it is a pointer type, we don't have to worry about any implicit 1922 // casts here. 1923 // FIXME: We don't allow floating point scalars as input. 1924 Expr *FirstArg = TheCall->getArg(0); 1925 ExprResult FirstArgResult = DefaultFunctionArrayLvalueConversion(FirstArg); 1926 if (FirstArgResult.isInvalid()) 1927 return ExprError(); 1928 FirstArg = FirstArgResult.get(); 1929 TheCall->setArg(0, FirstArg); 1930 1931 const PointerType *pointerType = FirstArg->getType()->getAs<PointerType>(); 1932 if (!pointerType) { 1933 Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer) 1934 << FirstArg->getType() << FirstArg->getSourceRange(); 1935 return ExprError(); 1936 } 1937 1938 QualType ValType = pointerType->getPointeeType(); 1939 if (!ValType->isIntegerType() && !ValType->isAnyPointerType() && 1940 !ValType->isBlockPointerType()) { 1941 Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer_intptr) 1942 << FirstArg->getType() << FirstArg->getSourceRange(); 1943 return ExprError(); 1944 } 1945 1946 switch (ValType.getObjCLifetime()) { 1947 case Qualifiers::OCL_None: 1948 case Qualifiers::OCL_ExplicitNone: 1949 // okay 1950 break; 1951 1952 case Qualifiers::OCL_Weak: 1953 case Qualifiers::OCL_Strong: 1954 case Qualifiers::OCL_Autoreleasing: 1955 Diag(DRE->getLocStart(), diag::err_arc_atomic_ownership) 1956 << ValType << FirstArg->getSourceRange(); 1957 return ExprError(); 1958 } 1959 1960 // Strip any qualifiers off ValType. 1961 ValType = ValType.getUnqualifiedType(); 1962 1963 // The majority of builtins return a value, but a few have special return 1964 // types, so allow them to override appropriately below. 1965 QualType ResultType = ValType; 1966 1967 // We need to figure out which concrete builtin this maps onto. For example, 1968 // __sync_fetch_and_add with a 2 byte object turns into 1969 // __sync_fetch_and_add_2. 1970 #define BUILTIN_ROW(x) \ 1971 { Builtin::BI##x##_1, Builtin::BI##x##_2, Builtin::BI##x##_4, \ 1972 Builtin::BI##x##_8, Builtin::BI##x##_16 } 1973 1974 static const unsigned BuiltinIndices[][5] = { 1975 BUILTIN_ROW(__sync_fetch_and_add), 1976 BUILTIN_ROW(__sync_fetch_and_sub), 1977 BUILTIN_ROW(__sync_fetch_and_or), 1978 BUILTIN_ROW(__sync_fetch_and_and), 1979 BUILTIN_ROW(__sync_fetch_and_xor), 1980 BUILTIN_ROW(__sync_fetch_and_nand), 1981 1982 BUILTIN_ROW(__sync_add_and_fetch), 1983 BUILTIN_ROW(__sync_sub_and_fetch), 1984 BUILTIN_ROW(__sync_and_and_fetch), 1985 BUILTIN_ROW(__sync_or_and_fetch), 1986 BUILTIN_ROW(__sync_xor_and_fetch), 1987 BUILTIN_ROW(__sync_nand_and_fetch), 1988 1989 BUILTIN_ROW(__sync_val_compare_and_swap), 1990 BUILTIN_ROW(__sync_bool_compare_and_swap), 1991 BUILTIN_ROW(__sync_lock_test_and_set), 1992 BUILTIN_ROW(__sync_lock_release), 1993 BUILTIN_ROW(__sync_swap) 1994 }; 1995 #undef BUILTIN_ROW 1996 1997 // Determine the index of the size. 1998 unsigned SizeIndex; 1999 switch (Context.getTypeSizeInChars(ValType).getQuantity()) { 2000 case 1: SizeIndex = 0; break; 2001 case 2: SizeIndex = 1; break; 2002 case 4: SizeIndex = 2; break; 2003 case 8: SizeIndex = 3; break; 2004 case 16: SizeIndex = 4; break; 2005 default: 2006 Diag(DRE->getLocStart(), diag::err_atomic_builtin_pointer_size) 2007 << FirstArg->getType() << FirstArg->getSourceRange(); 2008 return ExprError(); 2009 } 2010 2011 // Each of these builtins has one pointer argument, followed by some number of 2012 // values (0, 1 or 2) followed by a potentially empty varags list of stuff 2013 // that we ignore. Find out which row of BuiltinIndices to read from as well 2014 // as the number of fixed args. 2015 unsigned BuiltinID = FDecl->getBuiltinID(); 2016 unsigned BuiltinIndex, NumFixed = 1; 2017 bool WarnAboutSemanticsChange = false; 2018 switch (BuiltinID) { 2019 default: llvm_unreachable("Unknown overloaded atomic builtin!"); 2020 case Builtin::BI__sync_fetch_and_add: 2021 case Builtin::BI__sync_fetch_and_add_1: 2022 case Builtin::BI__sync_fetch_and_add_2: 2023 case Builtin::BI__sync_fetch_and_add_4: 2024 case Builtin::BI__sync_fetch_and_add_8: 2025 case Builtin::BI__sync_fetch_and_add_16: 2026 BuiltinIndex = 0; 2027 break; 2028 2029 case Builtin::BI__sync_fetch_and_sub: 2030 case Builtin::BI__sync_fetch_and_sub_1: 2031 case Builtin::BI__sync_fetch_and_sub_2: 2032 case Builtin::BI__sync_fetch_and_sub_4: 2033 case Builtin::BI__sync_fetch_and_sub_8: 2034 case Builtin::BI__sync_fetch_and_sub_16: 2035 BuiltinIndex = 1; 2036 break; 2037 2038 case Builtin::BI__sync_fetch_and_or: 2039 case Builtin::BI__sync_fetch_and_or_1: 2040 case Builtin::BI__sync_fetch_and_or_2: 2041 case Builtin::BI__sync_fetch_and_or_4: 2042 case Builtin::BI__sync_fetch_and_or_8: 2043 case Builtin::BI__sync_fetch_and_or_16: 2044 BuiltinIndex = 2; 2045 break; 2046 2047 case Builtin::BI__sync_fetch_and_and: 2048 case Builtin::BI__sync_fetch_and_and_1: 2049 case Builtin::BI__sync_fetch_and_and_2: 2050 case Builtin::BI__sync_fetch_and_and_4: 2051 case Builtin::BI__sync_fetch_and_and_8: 2052 case Builtin::BI__sync_fetch_and_and_16: 2053 BuiltinIndex = 3; 2054 break; 2055 2056 case Builtin::BI__sync_fetch_and_xor: 2057 case Builtin::BI__sync_fetch_and_xor_1: 2058 case Builtin::BI__sync_fetch_and_xor_2: 2059 case Builtin::BI__sync_fetch_and_xor_4: 2060 case Builtin::BI__sync_fetch_and_xor_8: 2061 case Builtin::BI__sync_fetch_and_xor_16: 2062 BuiltinIndex = 4; 2063 break; 2064 2065 case Builtin::BI__sync_fetch_and_nand: 2066 case Builtin::BI__sync_fetch_and_nand_1: 2067 case Builtin::BI__sync_fetch_and_nand_2: 2068 case Builtin::BI__sync_fetch_and_nand_4: 2069 case Builtin::BI__sync_fetch_and_nand_8: 2070 case Builtin::BI__sync_fetch_and_nand_16: 2071 BuiltinIndex = 5; 2072 WarnAboutSemanticsChange = true; 2073 break; 2074 2075 case Builtin::BI__sync_add_and_fetch: 2076 case Builtin::BI__sync_add_and_fetch_1: 2077 case Builtin::BI__sync_add_and_fetch_2: 2078 case Builtin::BI__sync_add_and_fetch_4: 2079 case Builtin::BI__sync_add_and_fetch_8: 2080 case Builtin::BI__sync_add_and_fetch_16: 2081 BuiltinIndex = 6; 2082 break; 2083 2084 case Builtin::BI__sync_sub_and_fetch: 2085 case Builtin::BI__sync_sub_and_fetch_1: 2086 case Builtin::BI__sync_sub_and_fetch_2: 2087 case Builtin::BI__sync_sub_and_fetch_4: 2088 case Builtin::BI__sync_sub_and_fetch_8: 2089 case Builtin::BI__sync_sub_and_fetch_16: 2090 BuiltinIndex = 7; 2091 break; 2092 2093 case Builtin::BI__sync_and_and_fetch: 2094 case Builtin::BI__sync_and_and_fetch_1: 2095 case Builtin::BI__sync_and_and_fetch_2: 2096 case Builtin::BI__sync_and_and_fetch_4: 2097 case Builtin::BI__sync_and_and_fetch_8: 2098 case Builtin::BI__sync_and_and_fetch_16: 2099 BuiltinIndex = 8; 2100 break; 2101 2102 case Builtin::BI__sync_or_and_fetch: 2103 case Builtin::BI__sync_or_and_fetch_1: 2104 case Builtin::BI__sync_or_and_fetch_2: 2105 case Builtin::BI__sync_or_and_fetch_4: 2106 case Builtin::BI__sync_or_and_fetch_8: 2107 case Builtin::BI__sync_or_and_fetch_16: 2108 BuiltinIndex = 9; 2109 break; 2110 2111 case Builtin::BI__sync_xor_and_fetch: 2112 case Builtin::BI__sync_xor_and_fetch_1: 2113 case Builtin::BI__sync_xor_and_fetch_2: 2114 case Builtin::BI__sync_xor_and_fetch_4: 2115 case Builtin::BI__sync_xor_and_fetch_8: 2116 case Builtin::BI__sync_xor_and_fetch_16: 2117 BuiltinIndex = 10; 2118 break; 2119 2120 case Builtin::BI__sync_nand_and_fetch: 2121 case Builtin::BI__sync_nand_and_fetch_1: 2122 case Builtin::BI__sync_nand_and_fetch_2: 2123 case Builtin::BI__sync_nand_and_fetch_4: 2124 case Builtin::BI__sync_nand_and_fetch_8: 2125 case Builtin::BI__sync_nand_and_fetch_16: 2126 BuiltinIndex = 11; 2127 WarnAboutSemanticsChange = true; 2128 break; 2129 2130 case Builtin::BI__sync_val_compare_and_swap: 2131 case Builtin::BI__sync_val_compare_and_swap_1: 2132 case Builtin::BI__sync_val_compare_and_swap_2: 2133 case Builtin::BI__sync_val_compare_and_swap_4: 2134 case Builtin::BI__sync_val_compare_and_swap_8: 2135 case Builtin::BI__sync_val_compare_and_swap_16: 2136 BuiltinIndex = 12; 2137 NumFixed = 2; 2138 break; 2139 2140 case Builtin::BI__sync_bool_compare_and_swap: 2141 case Builtin::BI__sync_bool_compare_and_swap_1: 2142 case Builtin::BI__sync_bool_compare_and_swap_2: 2143 case Builtin::BI__sync_bool_compare_and_swap_4: 2144 case Builtin::BI__sync_bool_compare_and_swap_8: 2145 case Builtin::BI__sync_bool_compare_and_swap_16: 2146 BuiltinIndex = 13; 2147 NumFixed = 2; 2148 ResultType = Context.BoolTy; 2149 break; 2150 2151 case Builtin::BI__sync_lock_test_and_set: 2152 case Builtin::BI__sync_lock_test_and_set_1: 2153 case Builtin::BI__sync_lock_test_and_set_2: 2154 case Builtin::BI__sync_lock_test_and_set_4: 2155 case Builtin::BI__sync_lock_test_and_set_8: 2156 case Builtin::BI__sync_lock_test_and_set_16: 2157 BuiltinIndex = 14; 2158 break; 2159 2160 case Builtin::BI__sync_lock_release: 2161 case Builtin::BI__sync_lock_release_1: 2162 case Builtin::BI__sync_lock_release_2: 2163 case Builtin::BI__sync_lock_release_4: 2164 case Builtin::BI__sync_lock_release_8: 2165 case Builtin::BI__sync_lock_release_16: 2166 BuiltinIndex = 15; 2167 NumFixed = 0; 2168 ResultType = Context.VoidTy; 2169 break; 2170 2171 case Builtin::BI__sync_swap: 2172 case Builtin::BI__sync_swap_1: 2173 case Builtin::BI__sync_swap_2: 2174 case Builtin::BI__sync_swap_4: 2175 case Builtin::BI__sync_swap_8: 2176 case Builtin::BI__sync_swap_16: 2177 BuiltinIndex = 16; 2178 break; 2179 } 2180 2181 // Now that we know how many fixed arguments we expect, first check that we 2182 // have at least that many. 2183 if (TheCall->getNumArgs() < 1+NumFixed) { 2184 Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args_at_least) 2185 << 0 << 1+NumFixed << TheCall->getNumArgs() 2186 << TheCall->getCallee()->getSourceRange(); 2187 return ExprError(); 2188 } 2189 2190 if (WarnAboutSemanticsChange) { 2191 Diag(TheCall->getLocEnd(), diag::warn_sync_fetch_and_nand_semantics_change) 2192 << TheCall->getCallee()->getSourceRange(); 2193 } 2194 2195 // Get the decl for the concrete builtin from this, we can tell what the 2196 // concrete integer type we should convert to is. 2197 unsigned NewBuiltinID = BuiltinIndices[BuiltinIndex][SizeIndex]; 2198 const char *NewBuiltinName = Context.BuiltinInfo.getName(NewBuiltinID); 2199 FunctionDecl *NewBuiltinDecl; 2200 if (NewBuiltinID == BuiltinID) 2201 NewBuiltinDecl = FDecl; 2202 else { 2203 // Perform builtin lookup to avoid redeclaring it. 2204 DeclarationName DN(&Context.Idents.get(NewBuiltinName)); 2205 LookupResult Res(*this, DN, DRE->getLocStart(), LookupOrdinaryName); 2206 LookupName(Res, TUScope, /*AllowBuiltinCreation=*/true); 2207 assert(Res.getFoundDecl()); 2208 NewBuiltinDecl = dyn_cast<FunctionDecl>(Res.getFoundDecl()); 2209 if (!NewBuiltinDecl) 2210 return ExprError(); 2211 } 2212 2213 // The first argument --- the pointer --- has a fixed type; we 2214 // deduce the types of the rest of the arguments accordingly. Walk 2215 // the remaining arguments, converting them to the deduced value type. 2216 for (unsigned i = 0; i != NumFixed; ++i) { 2217 ExprResult Arg = TheCall->getArg(i+1); 2218 2219 // GCC does an implicit conversion to the pointer or integer ValType. This 2220 // can fail in some cases (1i -> int**), check for this error case now. 2221 // Initialize the argument. 2222 InitializedEntity Entity = InitializedEntity::InitializeParameter(Context, 2223 ValType, /*consume*/ false); 2224 Arg = PerformCopyInitialization(Entity, SourceLocation(), Arg); 2225 if (Arg.isInvalid()) 2226 return ExprError(); 2227 2228 // Okay, we have something that *can* be converted to the right type. Check 2229 // to see if there is a potentially weird extension going on here. This can 2230 // happen when you do an atomic operation on something like an char* and 2231 // pass in 42. The 42 gets converted to char. This is even more strange 2232 // for things like 45.123 -> char, etc. 2233 // FIXME: Do this check. 2234 TheCall->setArg(i+1, Arg.get()); 2235 } 2236 2237 ASTContext& Context = this->getASTContext(); 2238 2239 // Create a new DeclRefExpr to refer to the new decl. 2240 DeclRefExpr* NewDRE = DeclRefExpr::Create( 2241 Context, 2242 DRE->getQualifierLoc(), 2243 SourceLocation(), 2244 NewBuiltinDecl, 2245 /*enclosing*/ false, 2246 DRE->getLocation(), 2247 Context.BuiltinFnTy, 2248 DRE->getValueKind()); 2249 2250 // Set the callee in the CallExpr. 2251 // FIXME: This loses syntactic information. 2252 QualType CalleePtrTy = Context.getPointerType(NewBuiltinDecl->getType()); 2253 ExprResult PromotedCall = ImpCastExprToType(NewDRE, CalleePtrTy, 2254 CK_BuiltinFnToFnPtr); 2255 TheCall->setCallee(PromotedCall.get()); 2256 2257 // Change the result type of the call to match the original value type. This 2258 // is arbitrary, but the codegen for these builtins ins design to handle it 2259 // gracefully. 2260 TheCall->setType(ResultType); 2261 2262 return TheCallResult; 2263 } 2264 2265 /// SemaBuiltinNontemporalOverloaded - We have a call to 2266 /// __builtin_nontemporal_store or __builtin_nontemporal_load, which is an 2267 /// overloaded function based on the pointer type of its last argument. 2268 /// 2269 /// This function goes through and does final semantic checking for these 2270 /// builtins. 2271 ExprResult Sema::SemaBuiltinNontemporalOverloaded(ExprResult TheCallResult) { 2272 CallExpr *TheCall = (CallExpr *)TheCallResult.get(); 2273 DeclRefExpr *DRE = 2274 cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts()); 2275 FunctionDecl *FDecl = cast<FunctionDecl>(DRE->getDecl()); 2276 unsigned BuiltinID = FDecl->getBuiltinID(); 2277 assert((BuiltinID == Builtin::BI__builtin_nontemporal_store || 2278 BuiltinID == Builtin::BI__builtin_nontemporal_load) && 2279 "Unexpected nontemporal load/store builtin!"); 2280 bool isStore = BuiltinID == Builtin::BI__builtin_nontemporal_store; 2281 unsigned numArgs = isStore ? 2 : 1; 2282 2283 // Ensure that we have the proper number of arguments. 2284 if (checkArgCount(*this, TheCall, numArgs)) 2285 return ExprError(); 2286 2287 // Inspect the last argument of the nontemporal builtin. This should always 2288 // be a pointer type, from which we imply the type of the memory access. 2289 // Because it is a pointer type, we don't have to worry about any implicit 2290 // casts here. 2291 Expr *PointerArg = TheCall->getArg(numArgs - 1); 2292 ExprResult PointerArgResult = 2293 DefaultFunctionArrayLvalueConversion(PointerArg); 2294 2295 if (PointerArgResult.isInvalid()) 2296 return ExprError(); 2297 PointerArg = PointerArgResult.get(); 2298 TheCall->setArg(numArgs - 1, PointerArg); 2299 2300 const PointerType *pointerType = PointerArg->getType()->getAs<PointerType>(); 2301 if (!pointerType) { 2302 Diag(DRE->getLocStart(), diag::err_nontemporal_builtin_must_be_pointer) 2303 << PointerArg->getType() << PointerArg->getSourceRange(); 2304 return ExprError(); 2305 } 2306 2307 QualType ValType = pointerType->getPointeeType(); 2308 2309 // Strip any qualifiers off ValType. 2310 ValType = ValType.getUnqualifiedType(); 2311 if (!ValType->isIntegerType() && !ValType->isAnyPointerType() && 2312 !ValType->isBlockPointerType() && !ValType->isFloatingType() && 2313 !ValType->isVectorType()) { 2314 Diag(DRE->getLocStart(), 2315 diag::err_nontemporal_builtin_must_be_pointer_intfltptr_or_vector) 2316 << PointerArg->getType() << PointerArg->getSourceRange(); 2317 return ExprError(); 2318 } 2319 2320 if (!isStore) { 2321 TheCall->setType(ValType); 2322 return TheCallResult; 2323 } 2324 2325 ExprResult ValArg = TheCall->getArg(0); 2326 InitializedEntity Entity = InitializedEntity::InitializeParameter( 2327 Context, ValType, /*consume*/ false); 2328 ValArg = PerformCopyInitialization(Entity, SourceLocation(), ValArg); 2329 if (ValArg.isInvalid()) 2330 return ExprError(); 2331 2332 TheCall->setArg(0, ValArg.get()); 2333 TheCall->setType(Context.VoidTy); 2334 return TheCallResult; 2335 } 2336 2337 /// CheckObjCString - Checks that the argument to the builtin 2338 /// CFString constructor is correct 2339 /// Note: It might also make sense to do the UTF-16 conversion here (would 2340 /// simplify the backend). 2341 bool Sema::CheckObjCString(Expr *Arg) { 2342 Arg = Arg->IgnoreParenCasts(); 2343 StringLiteral *Literal = dyn_cast<StringLiteral>(Arg); 2344 2345 if (!Literal || !Literal->isAscii()) { 2346 Diag(Arg->getLocStart(), diag::err_cfstring_literal_not_string_constant) 2347 << Arg->getSourceRange(); 2348 return true; 2349 } 2350 2351 if (Literal->containsNonAsciiOrNull()) { 2352 StringRef String = Literal->getString(); 2353 unsigned NumBytes = String.size(); 2354 SmallVector<UTF16, 128> ToBuf(NumBytes); 2355 const UTF8 *FromPtr = (const UTF8 *)String.data(); 2356 UTF16 *ToPtr = &ToBuf[0]; 2357 2358 ConversionResult Result = ConvertUTF8toUTF16(&FromPtr, FromPtr + NumBytes, 2359 &ToPtr, ToPtr + NumBytes, 2360 strictConversion); 2361 // Check for conversion failure. 2362 if (Result != conversionOK) 2363 Diag(Arg->getLocStart(), 2364 diag::warn_cfstring_truncated) << Arg->getSourceRange(); 2365 } 2366 return false; 2367 } 2368 2369 /// Check the arguments to '__builtin_va_start' or '__builtin_ms_va_start' 2370 /// for validity. Emit an error and return true on failure; return false 2371 /// on success. 2372 bool Sema::SemaBuiltinVAStartImpl(CallExpr *TheCall) { 2373 Expr *Fn = TheCall->getCallee(); 2374 if (TheCall->getNumArgs() > 2) { 2375 Diag(TheCall->getArg(2)->getLocStart(), 2376 diag::err_typecheck_call_too_many_args) 2377 << 0 /*function call*/ << 2 << TheCall->getNumArgs() 2378 << Fn->getSourceRange() 2379 << SourceRange(TheCall->getArg(2)->getLocStart(), 2380 (*(TheCall->arg_end()-1))->getLocEnd()); 2381 return true; 2382 } 2383 2384 if (TheCall->getNumArgs() < 2) { 2385 return Diag(TheCall->getLocEnd(), 2386 diag::err_typecheck_call_too_few_args_at_least) 2387 << 0 /*function call*/ << 2 << TheCall->getNumArgs(); 2388 } 2389 2390 // Type-check the first argument normally. 2391 if (checkBuiltinArgument(*this, TheCall, 0)) 2392 return true; 2393 2394 // Determine whether the current function is variadic or not. 2395 BlockScopeInfo *CurBlock = getCurBlock(); 2396 bool isVariadic; 2397 if (CurBlock) 2398 isVariadic = CurBlock->TheDecl->isVariadic(); 2399 else if (FunctionDecl *FD = getCurFunctionDecl()) 2400 isVariadic = FD->isVariadic(); 2401 else 2402 isVariadic = getCurMethodDecl()->isVariadic(); 2403 2404 if (!isVariadic) { 2405 Diag(Fn->getLocStart(), diag::err_va_start_used_in_non_variadic_function); 2406 return true; 2407 } 2408 2409 // Verify that the second argument to the builtin is the last argument of the 2410 // current function or method. 2411 bool SecondArgIsLastNamedArgument = false; 2412 const Expr *Arg = TheCall->getArg(1)->IgnoreParenCasts(); 2413 2414 // These are valid if SecondArgIsLastNamedArgument is false after the next 2415 // block. 2416 QualType Type; 2417 SourceLocation ParamLoc; 2418 2419 if (const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(Arg)) { 2420 if (const ParmVarDecl *PV = dyn_cast<ParmVarDecl>(DR->getDecl())) { 2421 // FIXME: This isn't correct for methods (results in bogus warning). 2422 // Get the last formal in the current function. 2423 const ParmVarDecl *LastArg; 2424 if (CurBlock) 2425 LastArg = *(CurBlock->TheDecl->param_end()-1); 2426 else if (FunctionDecl *FD = getCurFunctionDecl()) 2427 LastArg = *(FD->param_end()-1); 2428 else 2429 LastArg = *(getCurMethodDecl()->param_end()-1); 2430 SecondArgIsLastNamedArgument = PV == LastArg; 2431 2432 Type = PV->getType(); 2433 ParamLoc = PV->getLocation(); 2434 } 2435 } 2436 2437 if (!SecondArgIsLastNamedArgument) 2438 Diag(TheCall->getArg(1)->getLocStart(), 2439 diag::warn_second_parameter_of_va_start_not_last_named_argument); 2440 else if (Type->isReferenceType()) { 2441 Diag(Arg->getLocStart(), 2442 diag::warn_va_start_of_reference_type_is_undefined); 2443 Diag(ParamLoc, diag::note_parameter_type) << Type; 2444 } 2445 2446 TheCall->setType(Context.VoidTy); 2447 return false; 2448 } 2449 2450 /// Check the arguments to '__builtin_va_start' for validity, and that 2451 /// it was called from a function of the native ABI. 2452 /// Emit an error and return true on failure; return false on success. 2453 bool Sema::SemaBuiltinVAStart(CallExpr *TheCall) { 2454 // On x86-64 Unix, don't allow this in Win64 ABI functions. 2455 // On x64 Windows, don't allow this in System V ABI functions. 2456 // (Yes, that means there's no corresponding way to support variadic 2457 // System V ABI functions on Windows.) 2458 if (Context.getTargetInfo().getTriple().getArch() == llvm::Triple::x86_64) { 2459 unsigned OS = Context.getTargetInfo().getTriple().getOS(); 2460 clang::CallingConv CC = CC_C; 2461 if (const FunctionDecl *FD = getCurFunctionDecl()) 2462 CC = FD->getType()->getAs<FunctionType>()->getCallConv(); 2463 if ((OS == llvm::Triple::Win32 && CC == CC_X86_64SysV) || 2464 (OS != llvm::Triple::Win32 && CC == CC_X86_64Win64)) 2465 return Diag(TheCall->getCallee()->getLocStart(), 2466 diag::err_va_start_used_in_wrong_abi_function) 2467 << (OS != llvm::Triple::Win32); 2468 } 2469 return SemaBuiltinVAStartImpl(TheCall); 2470 } 2471 2472 /// Check the arguments to '__builtin_ms_va_start' for validity, and that 2473 /// it was called from a Win64 ABI function. 2474 /// Emit an error and return true on failure; return false on success. 2475 bool Sema::SemaBuiltinMSVAStart(CallExpr *TheCall) { 2476 // This only makes sense for x86-64. 2477 const llvm::Triple &TT = Context.getTargetInfo().getTriple(); 2478 Expr *Callee = TheCall->getCallee(); 2479 if (TT.getArch() != llvm::Triple::x86_64) 2480 return Diag(Callee->getLocStart(), diag::err_x86_builtin_32_bit_tgt); 2481 // Don't allow this in System V ABI functions. 2482 clang::CallingConv CC = CC_C; 2483 if (const FunctionDecl *FD = getCurFunctionDecl()) 2484 CC = FD->getType()->getAs<FunctionType>()->getCallConv(); 2485 if (CC == CC_X86_64SysV || 2486 (TT.getOS() != llvm::Triple::Win32 && CC != CC_X86_64Win64)) 2487 return Diag(Callee->getLocStart(), 2488 diag::err_ms_va_start_used_in_sysv_function); 2489 return SemaBuiltinVAStartImpl(TheCall); 2490 } 2491 2492 bool Sema::SemaBuiltinVAStartARM(CallExpr *Call) { 2493 // void __va_start(va_list *ap, const char *named_addr, size_t slot_size, 2494 // const char *named_addr); 2495 2496 Expr *Func = Call->getCallee(); 2497 2498 if (Call->getNumArgs() < 3) 2499 return Diag(Call->getLocEnd(), 2500 diag::err_typecheck_call_too_few_args_at_least) 2501 << 0 /*function call*/ << 3 << Call->getNumArgs(); 2502 2503 // Determine whether the current function is variadic or not. 2504 bool IsVariadic; 2505 if (BlockScopeInfo *CurBlock = getCurBlock()) 2506 IsVariadic = CurBlock->TheDecl->isVariadic(); 2507 else if (FunctionDecl *FD = getCurFunctionDecl()) 2508 IsVariadic = FD->isVariadic(); 2509 else if (ObjCMethodDecl *MD = getCurMethodDecl()) 2510 IsVariadic = MD->isVariadic(); 2511 else 2512 llvm_unreachable("unexpected statement type"); 2513 2514 if (!IsVariadic) { 2515 Diag(Func->getLocStart(), diag::err_va_start_used_in_non_variadic_function); 2516 return true; 2517 } 2518 2519 // Type-check the first argument normally. 2520 if (checkBuiltinArgument(*this, Call, 0)) 2521 return true; 2522 2523 const struct { 2524 unsigned ArgNo; 2525 QualType Type; 2526 } ArgumentTypes[] = { 2527 { 1, Context.getPointerType(Context.CharTy.withConst()) }, 2528 { 2, Context.getSizeType() }, 2529 }; 2530 2531 for (const auto &AT : ArgumentTypes) { 2532 const Expr *Arg = Call->getArg(AT.ArgNo)->IgnoreParens(); 2533 if (Arg->getType().getCanonicalType() == AT.Type.getCanonicalType()) 2534 continue; 2535 Diag(Arg->getLocStart(), diag::err_typecheck_convert_incompatible) 2536 << Arg->getType() << AT.Type << 1 /* different class */ 2537 << 0 /* qualifier difference */ << 3 /* parameter mismatch */ 2538 << AT.ArgNo + 1 << Arg->getType() << AT.Type; 2539 } 2540 2541 return false; 2542 } 2543 2544 /// SemaBuiltinUnorderedCompare - Handle functions like __builtin_isgreater and 2545 /// friends. This is declared to take (...), so we have to check everything. 2546 bool Sema::SemaBuiltinUnorderedCompare(CallExpr *TheCall) { 2547 if (TheCall->getNumArgs() < 2) 2548 return Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args) 2549 << 0 << 2 << TheCall->getNumArgs()/*function call*/; 2550 if (TheCall->getNumArgs() > 2) 2551 return Diag(TheCall->getArg(2)->getLocStart(), 2552 diag::err_typecheck_call_too_many_args) 2553 << 0 /*function call*/ << 2 << TheCall->getNumArgs() 2554 << SourceRange(TheCall->getArg(2)->getLocStart(), 2555 (*(TheCall->arg_end()-1))->getLocEnd()); 2556 2557 ExprResult OrigArg0 = TheCall->getArg(0); 2558 ExprResult OrigArg1 = TheCall->getArg(1); 2559 2560 // Do standard promotions between the two arguments, returning their common 2561 // type. 2562 QualType Res = UsualArithmeticConversions(OrigArg0, OrigArg1, false); 2563 if (OrigArg0.isInvalid() || OrigArg1.isInvalid()) 2564 return true; 2565 2566 // Make sure any conversions are pushed back into the call; this is 2567 // type safe since unordered compare builtins are declared as "_Bool 2568 // foo(...)". 2569 TheCall->setArg(0, OrigArg0.get()); 2570 TheCall->setArg(1, OrigArg1.get()); 2571 2572 if (OrigArg0.get()->isTypeDependent() || OrigArg1.get()->isTypeDependent()) 2573 return false; 2574 2575 // If the common type isn't a real floating type, then the arguments were 2576 // invalid for this operation. 2577 if (Res.isNull() || !Res->isRealFloatingType()) 2578 return Diag(OrigArg0.get()->getLocStart(), 2579 diag::err_typecheck_call_invalid_ordered_compare) 2580 << OrigArg0.get()->getType() << OrigArg1.get()->getType() 2581 << SourceRange(OrigArg0.get()->getLocStart(), OrigArg1.get()->getLocEnd()); 2582 2583 return false; 2584 } 2585 2586 /// SemaBuiltinSemaBuiltinFPClassification - Handle functions like 2587 /// __builtin_isnan and friends. This is declared to take (...), so we have 2588 /// to check everything. We expect the last argument to be a floating point 2589 /// value. 2590 bool Sema::SemaBuiltinFPClassification(CallExpr *TheCall, unsigned NumArgs) { 2591 if (TheCall->getNumArgs() < NumArgs) 2592 return Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args) 2593 << 0 << NumArgs << TheCall->getNumArgs()/*function call*/; 2594 if (TheCall->getNumArgs() > NumArgs) 2595 return Diag(TheCall->getArg(NumArgs)->getLocStart(), 2596 diag::err_typecheck_call_too_many_args) 2597 << 0 /*function call*/ << NumArgs << TheCall->getNumArgs() 2598 << SourceRange(TheCall->getArg(NumArgs)->getLocStart(), 2599 (*(TheCall->arg_end()-1))->getLocEnd()); 2600 2601 Expr *OrigArg = TheCall->getArg(NumArgs-1); 2602 2603 if (OrigArg->isTypeDependent()) 2604 return false; 2605 2606 // This operation requires a non-_Complex floating-point number. 2607 if (!OrigArg->getType()->isRealFloatingType()) 2608 return Diag(OrigArg->getLocStart(), 2609 diag::err_typecheck_call_invalid_unary_fp) 2610 << OrigArg->getType() << OrigArg->getSourceRange(); 2611 2612 // If this is an implicit conversion from float -> double, remove it. 2613 if (ImplicitCastExpr *Cast = dyn_cast<ImplicitCastExpr>(OrigArg)) { 2614 Expr *CastArg = Cast->getSubExpr(); 2615 if (CastArg->getType()->isSpecificBuiltinType(BuiltinType::Float)) { 2616 assert(Cast->getType()->isSpecificBuiltinType(BuiltinType::Double) && 2617 "promotion from float to double is the only expected cast here"); 2618 Cast->setSubExpr(nullptr); 2619 TheCall->setArg(NumArgs-1, CastArg); 2620 } 2621 } 2622 2623 return false; 2624 } 2625 2626 /// SemaBuiltinShuffleVector - Handle __builtin_shufflevector. 2627 // This is declared to take (...), so we have to check everything. 2628 ExprResult Sema::SemaBuiltinShuffleVector(CallExpr *TheCall) { 2629 if (TheCall->getNumArgs() < 2) 2630 return ExprError(Diag(TheCall->getLocEnd(), 2631 diag::err_typecheck_call_too_few_args_at_least) 2632 << 0 /*function call*/ << 2 << TheCall->getNumArgs() 2633 << TheCall->getSourceRange()); 2634 2635 // Determine which of the following types of shufflevector we're checking: 2636 // 1) unary, vector mask: (lhs, mask) 2637 // 2) binary, vector mask: (lhs, rhs, mask) 2638 // 3) binary, scalar mask: (lhs, rhs, index, ..., index) 2639 QualType resType = TheCall->getArg(0)->getType(); 2640 unsigned numElements = 0; 2641 2642 if (!TheCall->getArg(0)->isTypeDependent() && 2643 !TheCall->getArg(1)->isTypeDependent()) { 2644 QualType LHSType = TheCall->getArg(0)->getType(); 2645 QualType RHSType = TheCall->getArg(1)->getType(); 2646 2647 if (!LHSType->isVectorType() || !RHSType->isVectorType()) 2648 return ExprError(Diag(TheCall->getLocStart(), 2649 diag::err_shufflevector_non_vector) 2650 << SourceRange(TheCall->getArg(0)->getLocStart(), 2651 TheCall->getArg(1)->getLocEnd())); 2652 2653 numElements = LHSType->getAs<VectorType>()->getNumElements(); 2654 unsigned numResElements = TheCall->getNumArgs() - 2; 2655 2656 // Check to see if we have a call with 2 vector arguments, the unary shuffle 2657 // with mask. If so, verify that RHS is an integer vector type with the 2658 // same number of elts as lhs. 2659 if (TheCall->getNumArgs() == 2) { 2660 if (!RHSType->hasIntegerRepresentation() || 2661 RHSType->getAs<VectorType>()->getNumElements() != numElements) 2662 return ExprError(Diag(TheCall->getLocStart(), 2663 diag::err_shufflevector_incompatible_vector) 2664 << SourceRange(TheCall->getArg(1)->getLocStart(), 2665 TheCall->getArg(1)->getLocEnd())); 2666 } else if (!Context.hasSameUnqualifiedType(LHSType, RHSType)) { 2667 return ExprError(Diag(TheCall->getLocStart(), 2668 diag::err_shufflevector_incompatible_vector) 2669 << SourceRange(TheCall->getArg(0)->getLocStart(), 2670 TheCall->getArg(1)->getLocEnd())); 2671 } else if (numElements != numResElements) { 2672 QualType eltType = LHSType->getAs<VectorType>()->getElementType(); 2673 resType = Context.getVectorType(eltType, numResElements, 2674 VectorType::GenericVector); 2675 } 2676 } 2677 2678 for (unsigned i = 2; i < TheCall->getNumArgs(); i++) { 2679 if (TheCall->getArg(i)->isTypeDependent() || 2680 TheCall->getArg(i)->isValueDependent()) 2681 continue; 2682 2683 llvm::APSInt Result(32); 2684 if (!TheCall->getArg(i)->isIntegerConstantExpr(Result, Context)) 2685 return ExprError(Diag(TheCall->getLocStart(), 2686 diag::err_shufflevector_nonconstant_argument) 2687 << TheCall->getArg(i)->getSourceRange()); 2688 2689 // Allow -1 which will be translated to undef in the IR. 2690 if (Result.isSigned() && Result.isAllOnesValue()) 2691 continue; 2692 2693 if (Result.getActiveBits() > 64 || Result.getZExtValue() >= numElements*2) 2694 return ExprError(Diag(TheCall->getLocStart(), 2695 diag::err_shufflevector_argument_too_large) 2696 << TheCall->getArg(i)->getSourceRange()); 2697 } 2698 2699 SmallVector<Expr*, 32> exprs; 2700 2701 for (unsigned i = 0, e = TheCall->getNumArgs(); i != e; i++) { 2702 exprs.push_back(TheCall->getArg(i)); 2703 TheCall->setArg(i, nullptr); 2704 } 2705 2706 return new (Context) ShuffleVectorExpr(Context, exprs, resType, 2707 TheCall->getCallee()->getLocStart(), 2708 TheCall->getRParenLoc()); 2709 } 2710 2711 /// SemaConvertVectorExpr - Handle __builtin_convertvector 2712 ExprResult Sema::SemaConvertVectorExpr(Expr *E, TypeSourceInfo *TInfo, 2713 SourceLocation BuiltinLoc, 2714 SourceLocation RParenLoc) { 2715 ExprValueKind VK = VK_RValue; 2716 ExprObjectKind OK = OK_Ordinary; 2717 QualType DstTy = TInfo->getType(); 2718 QualType SrcTy = E->getType(); 2719 2720 if (!SrcTy->isVectorType() && !SrcTy->isDependentType()) 2721 return ExprError(Diag(BuiltinLoc, 2722 diag::err_convertvector_non_vector) 2723 << E->getSourceRange()); 2724 if (!DstTy->isVectorType() && !DstTy->isDependentType()) 2725 return ExprError(Diag(BuiltinLoc, 2726 diag::err_convertvector_non_vector_type)); 2727 2728 if (!SrcTy->isDependentType() && !DstTy->isDependentType()) { 2729 unsigned SrcElts = SrcTy->getAs<VectorType>()->getNumElements(); 2730 unsigned DstElts = DstTy->getAs<VectorType>()->getNumElements(); 2731 if (SrcElts != DstElts) 2732 return ExprError(Diag(BuiltinLoc, 2733 diag::err_convertvector_incompatible_vector) 2734 << E->getSourceRange()); 2735 } 2736 2737 return new (Context) 2738 ConvertVectorExpr(E, TInfo, DstTy, VK, OK, BuiltinLoc, RParenLoc); 2739 } 2740 2741 /// SemaBuiltinPrefetch - Handle __builtin_prefetch. 2742 // This is declared to take (const void*, ...) and can take two 2743 // optional constant int args. 2744 bool Sema::SemaBuiltinPrefetch(CallExpr *TheCall) { 2745 unsigned NumArgs = TheCall->getNumArgs(); 2746 2747 if (NumArgs > 3) 2748 return Diag(TheCall->getLocEnd(), 2749 diag::err_typecheck_call_too_many_args_at_most) 2750 << 0 /*function call*/ << 3 << NumArgs 2751 << TheCall->getSourceRange(); 2752 2753 // Argument 0 is checked for us and the remaining arguments must be 2754 // constant integers. 2755 for (unsigned i = 1; i != NumArgs; ++i) 2756 if (SemaBuiltinConstantArgRange(TheCall, i, 0, i == 1 ? 1 : 3)) 2757 return true; 2758 2759 return false; 2760 } 2761 2762 /// SemaBuiltinAssume - Handle __assume (MS Extension). 2763 // __assume does not evaluate its arguments, and should warn if its argument 2764 // has side effects. 2765 bool Sema::SemaBuiltinAssume(CallExpr *TheCall) { 2766 Expr *Arg = TheCall->getArg(0); 2767 if (Arg->isInstantiationDependent()) return false; 2768 2769 if (Arg->HasSideEffects(Context)) 2770 Diag(Arg->getLocStart(), diag::warn_assume_side_effects) 2771 << Arg->getSourceRange() 2772 << cast<FunctionDecl>(TheCall->getCalleeDecl())->getIdentifier(); 2773 2774 return false; 2775 } 2776 2777 /// Handle __builtin_assume_aligned. This is declared 2778 /// as (const void*, size_t, ...) and can take one optional constant int arg. 2779 bool Sema::SemaBuiltinAssumeAligned(CallExpr *TheCall) { 2780 unsigned NumArgs = TheCall->getNumArgs(); 2781 2782 if (NumArgs > 3) 2783 return Diag(TheCall->getLocEnd(), 2784 diag::err_typecheck_call_too_many_args_at_most) 2785 << 0 /*function call*/ << 3 << NumArgs 2786 << TheCall->getSourceRange(); 2787 2788 // The alignment must be a constant integer. 2789 Expr *Arg = TheCall->getArg(1); 2790 2791 // We can't check the value of a dependent argument. 2792 if (!Arg->isTypeDependent() && !Arg->isValueDependent()) { 2793 llvm::APSInt Result; 2794 if (SemaBuiltinConstantArg(TheCall, 1, Result)) 2795 return true; 2796 2797 if (!Result.isPowerOf2()) 2798 return Diag(TheCall->getLocStart(), 2799 diag::err_alignment_not_power_of_two) 2800 << Arg->getSourceRange(); 2801 } 2802 2803 if (NumArgs > 2) { 2804 ExprResult Arg(TheCall->getArg(2)); 2805 InitializedEntity Entity = InitializedEntity::InitializeParameter(Context, 2806 Context.getSizeType(), false); 2807 Arg = PerformCopyInitialization(Entity, SourceLocation(), Arg); 2808 if (Arg.isInvalid()) return true; 2809 TheCall->setArg(2, Arg.get()); 2810 } 2811 2812 return false; 2813 } 2814 2815 /// SemaBuiltinConstantArg - Handle a check if argument ArgNum of CallExpr 2816 /// TheCall is a constant expression. 2817 bool Sema::SemaBuiltinConstantArg(CallExpr *TheCall, int ArgNum, 2818 llvm::APSInt &Result) { 2819 Expr *Arg = TheCall->getArg(ArgNum); 2820 DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts()); 2821 FunctionDecl *FDecl = cast<FunctionDecl>(DRE->getDecl()); 2822 2823 if (Arg->isTypeDependent() || Arg->isValueDependent()) return false; 2824 2825 if (!Arg->isIntegerConstantExpr(Result, Context)) 2826 return Diag(TheCall->getLocStart(), diag::err_constant_integer_arg_type) 2827 << FDecl->getDeclName() << Arg->getSourceRange(); 2828 2829 return false; 2830 } 2831 2832 /// SemaBuiltinConstantArgRange - Handle a check if argument ArgNum of CallExpr 2833 /// TheCall is a constant expression in the range [Low, High]. 2834 bool Sema::SemaBuiltinConstantArgRange(CallExpr *TheCall, int ArgNum, 2835 int Low, int High) { 2836 llvm::APSInt Result; 2837 2838 // We can't check the value of a dependent argument. 2839 Expr *Arg = TheCall->getArg(ArgNum); 2840 if (Arg->isTypeDependent() || Arg->isValueDependent()) 2841 return false; 2842 2843 // Check constant-ness first. 2844 if (SemaBuiltinConstantArg(TheCall, ArgNum, Result)) 2845 return true; 2846 2847 if (Result.getSExtValue() < Low || Result.getSExtValue() > High) 2848 return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range) 2849 << Low << High << Arg->getSourceRange(); 2850 2851 return false; 2852 } 2853 2854 /// SemaBuiltinARMSpecialReg - Handle a check if argument ArgNum of CallExpr 2855 /// TheCall is an ARM/AArch64 special register string literal. 2856 bool Sema::SemaBuiltinARMSpecialReg(unsigned BuiltinID, CallExpr *TheCall, 2857 int ArgNum, unsigned ExpectedFieldNum, 2858 bool AllowName) { 2859 bool IsARMBuiltin = BuiltinID == ARM::BI__builtin_arm_rsr64 || 2860 BuiltinID == ARM::BI__builtin_arm_wsr64 || 2861 BuiltinID == ARM::BI__builtin_arm_rsr || 2862 BuiltinID == ARM::BI__builtin_arm_rsrp || 2863 BuiltinID == ARM::BI__builtin_arm_wsr || 2864 BuiltinID == ARM::BI__builtin_arm_wsrp; 2865 bool IsAArch64Builtin = BuiltinID == AArch64::BI__builtin_arm_rsr64 || 2866 BuiltinID == AArch64::BI__builtin_arm_wsr64 || 2867 BuiltinID == AArch64::BI__builtin_arm_rsr || 2868 BuiltinID == AArch64::BI__builtin_arm_rsrp || 2869 BuiltinID == AArch64::BI__builtin_arm_wsr || 2870 BuiltinID == AArch64::BI__builtin_arm_wsrp; 2871 assert((IsARMBuiltin || IsAArch64Builtin) && "Unexpected ARM builtin."); 2872 2873 // We can't check the value of a dependent argument. 2874 Expr *Arg = TheCall->getArg(ArgNum); 2875 if (Arg->isTypeDependent() || Arg->isValueDependent()) 2876 return false; 2877 2878 // Check if the argument is a string literal. 2879 if (!isa<StringLiteral>(Arg->IgnoreParenImpCasts())) 2880 return Diag(TheCall->getLocStart(), diag::err_expr_not_string_literal) 2881 << Arg->getSourceRange(); 2882 2883 // Check the type of special register given. 2884 StringRef Reg = cast<StringLiteral>(Arg->IgnoreParenImpCasts())->getString(); 2885 SmallVector<StringRef, 6> Fields; 2886 Reg.split(Fields, ":"); 2887 2888 if (Fields.size() != ExpectedFieldNum && !(AllowName && Fields.size() == 1)) 2889 return Diag(TheCall->getLocStart(), diag::err_arm_invalid_specialreg) 2890 << Arg->getSourceRange(); 2891 2892 // If the string is the name of a register then we cannot check that it is 2893 // valid here but if the string is of one the forms described in ACLE then we 2894 // can check that the supplied fields are integers and within the valid 2895 // ranges. 2896 if (Fields.size() > 1) { 2897 bool FiveFields = Fields.size() == 5; 2898 2899 bool ValidString = true; 2900 if (IsARMBuiltin) { 2901 ValidString &= Fields[0].startswith_lower("cp") || 2902 Fields[0].startswith_lower("p"); 2903 if (ValidString) 2904 Fields[0] = 2905 Fields[0].drop_front(Fields[0].startswith_lower("cp") ? 2 : 1); 2906 2907 ValidString &= Fields[2].startswith_lower("c"); 2908 if (ValidString) 2909 Fields[2] = Fields[2].drop_front(1); 2910 2911 if (FiveFields) { 2912 ValidString &= Fields[3].startswith_lower("c"); 2913 if (ValidString) 2914 Fields[3] = Fields[3].drop_front(1); 2915 } 2916 } 2917 2918 SmallVector<int, 5> Ranges; 2919 if (FiveFields) 2920 Ranges.append({IsAArch64Builtin ? 1 : 15, 7, 7, 15, 15}); 2921 else 2922 Ranges.append({15, 7, 15}); 2923 2924 for (unsigned i=0; i<Fields.size(); ++i) { 2925 int IntField; 2926 ValidString &= !Fields[i].getAsInteger(10, IntField); 2927 ValidString &= (IntField >= 0 && IntField <= Ranges[i]); 2928 } 2929 2930 if (!ValidString) 2931 return Diag(TheCall->getLocStart(), diag::err_arm_invalid_specialreg) 2932 << Arg->getSourceRange(); 2933 2934 } else if (IsAArch64Builtin && Fields.size() == 1) { 2935 // If the register name is one of those that appear in the condition below 2936 // and the special register builtin being used is one of the write builtins, 2937 // then we require that the argument provided for writing to the register 2938 // is an integer constant expression. This is because it will be lowered to 2939 // an MSR (immediate) instruction, so we need to know the immediate at 2940 // compile time. 2941 if (TheCall->getNumArgs() != 2) 2942 return false; 2943 2944 std::string RegLower = Reg.lower(); 2945 if (RegLower != "spsel" && RegLower != "daifset" && RegLower != "daifclr" && 2946 RegLower != "pan" && RegLower != "uao") 2947 return false; 2948 2949 return SemaBuiltinConstantArgRange(TheCall, 1, 0, 15); 2950 } 2951 2952 return false; 2953 } 2954 2955 /// SemaBuiltinCpuSupports - Handle __builtin_cpu_supports(char *). 2956 /// This checks that the target supports __builtin_cpu_supports and 2957 /// that the string argument is constant and valid. 2958 bool Sema::SemaBuiltinCpuSupports(CallExpr *TheCall) { 2959 Expr *Arg = TheCall->getArg(0); 2960 2961 // Check if the argument is a string literal. 2962 if (!isa<StringLiteral>(Arg->IgnoreParenImpCasts())) 2963 return Diag(TheCall->getLocStart(), diag::err_expr_not_string_literal) 2964 << Arg->getSourceRange(); 2965 2966 // Check the contents of the string. 2967 StringRef Feature = 2968 cast<StringLiteral>(Arg->IgnoreParenImpCasts())->getString(); 2969 if (!Context.getTargetInfo().validateCpuSupports(Feature)) 2970 return Diag(TheCall->getLocStart(), diag::err_invalid_cpu_supports) 2971 << Arg->getSourceRange(); 2972 return false; 2973 } 2974 2975 /// SemaBuiltinLongjmp - Handle __builtin_longjmp(void *env[5], int val). 2976 /// This checks that the target supports __builtin_longjmp and 2977 /// that val is a constant 1. 2978 bool Sema::SemaBuiltinLongjmp(CallExpr *TheCall) { 2979 if (!Context.getTargetInfo().hasSjLjLowering()) 2980 return Diag(TheCall->getLocStart(), diag::err_builtin_longjmp_unsupported) 2981 << SourceRange(TheCall->getLocStart(), TheCall->getLocEnd()); 2982 2983 Expr *Arg = TheCall->getArg(1); 2984 llvm::APSInt Result; 2985 2986 // TODO: This is less than ideal. Overload this to take a value. 2987 if (SemaBuiltinConstantArg(TheCall, 1, Result)) 2988 return true; 2989 2990 if (Result != 1) 2991 return Diag(TheCall->getLocStart(), diag::err_builtin_longjmp_invalid_val) 2992 << SourceRange(Arg->getLocStart(), Arg->getLocEnd()); 2993 2994 return false; 2995 } 2996 2997 2998 /// SemaBuiltinSetjmp - Handle __builtin_setjmp(void *env[5]). 2999 /// This checks that the target supports __builtin_setjmp. 3000 bool Sema::SemaBuiltinSetjmp(CallExpr *TheCall) { 3001 if (!Context.getTargetInfo().hasSjLjLowering()) 3002 return Diag(TheCall->getLocStart(), diag::err_builtin_setjmp_unsupported) 3003 << SourceRange(TheCall->getLocStart(), TheCall->getLocEnd()); 3004 return false; 3005 } 3006 3007 namespace { 3008 enum StringLiteralCheckType { 3009 SLCT_NotALiteral, 3010 SLCT_UncheckedLiteral, 3011 SLCT_CheckedLiteral 3012 }; 3013 } 3014 3015 // Determine if an expression is a string literal or constant string. 3016 // If this function returns false on the arguments to a function expecting a 3017 // format string, we will usually need to emit a warning. 3018 // True string literals are then checked by CheckFormatString. 3019 static StringLiteralCheckType 3020 checkFormatStringExpr(Sema &S, const Expr *E, ArrayRef<const Expr *> Args, 3021 bool HasVAListArg, unsigned format_idx, 3022 unsigned firstDataArg, Sema::FormatStringType Type, 3023 Sema::VariadicCallType CallType, bool InFunctionCall, 3024 llvm::SmallBitVector &CheckedVarArgs) { 3025 tryAgain: 3026 if (E->isTypeDependent() || E->isValueDependent()) 3027 return SLCT_NotALiteral; 3028 3029 E = E->IgnoreParenCasts(); 3030 3031 if (E->isNullPointerConstant(S.Context, Expr::NPC_ValueDependentIsNotNull)) 3032 // Technically -Wformat-nonliteral does not warn about this case. 3033 // The behavior of printf and friends in this case is implementation 3034 // dependent. Ideally if the format string cannot be null then 3035 // it should have a 'nonnull' attribute in the function prototype. 3036 return SLCT_UncheckedLiteral; 3037 3038 switch (E->getStmtClass()) { 3039 case Stmt::BinaryConditionalOperatorClass: 3040 case Stmt::ConditionalOperatorClass: { 3041 // The expression is a literal if both sub-expressions were, and it was 3042 // completely checked only if both sub-expressions were checked. 3043 const AbstractConditionalOperator *C = 3044 cast<AbstractConditionalOperator>(E); 3045 StringLiteralCheckType Left = 3046 checkFormatStringExpr(S, C->getTrueExpr(), Args, 3047 HasVAListArg, format_idx, firstDataArg, 3048 Type, CallType, InFunctionCall, CheckedVarArgs); 3049 if (Left == SLCT_NotALiteral) 3050 return SLCT_NotALiteral; 3051 StringLiteralCheckType Right = 3052 checkFormatStringExpr(S, C->getFalseExpr(), Args, 3053 HasVAListArg, format_idx, firstDataArg, 3054 Type, CallType, InFunctionCall, CheckedVarArgs); 3055 return Left < Right ? Left : Right; 3056 } 3057 3058 case Stmt::ImplicitCastExprClass: { 3059 E = cast<ImplicitCastExpr>(E)->getSubExpr(); 3060 goto tryAgain; 3061 } 3062 3063 case Stmt::OpaqueValueExprClass: 3064 if (const Expr *src = cast<OpaqueValueExpr>(E)->getSourceExpr()) { 3065 E = src; 3066 goto tryAgain; 3067 } 3068 return SLCT_NotALiteral; 3069 3070 case Stmt::PredefinedExprClass: 3071 // While __func__, etc., are technically not string literals, they 3072 // cannot contain format specifiers and thus are not a security 3073 // liability. 3074 return SLCT_UncheckedLiteral; 3075 3076 case Stmt::DeclRefExprClass: { 3077 const DeclRefExpr *DR = cast<DeclRefExpr>(E); 3078 3079 // As an exception, do not flag errors for variables binding to 3080 // const string literals. 3081 if (const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl())) { 3082 bool isConstant = false; 3083 QualType T = DR->getType(); 3084 3085 if (const ArrayType *AT = S.Context.getAsArrayType(T)) { 3086 isConstant = AT->getElementType().isConstant(S.Context); 3087 } else if (const PointerType *PT = T->getAs<PointerType>()) { 3088 isConstant = T.isConstant(S.Context) && 3089 PT->getPointeeType().isConstant(S.Context); 3090 } else if (T->isObjCObjectPointerType()) { 3091 // In ObjC, there is usually no "const ObjectPointer" type, 3092 // so don't check if the pointee type is constant. 3093 isConstant = T.isConstant(S.Context); 3094 } 3095 3096 if (isConstant) { 3097 if (const Expr *Init = VD->getAnyInitializer()) { 3098 // Look through initializers like const char c[] = { "foo" } 3099 if (const InitListExpr *InitList = dyn_cast<InitListExpr>(Init)) { 3100 if (InitList->isStringLiteralInit()) 3101 Init = InitList->getInit(0)->IgnoreParenImpCasts(); 3102 } 3103 return checkFormatStringExpr(S, Init, Args, 3104 HasVAListArg, format_idx, 3105 firstDataArg, Type, CallType, 3106 /*InFunctionCall*/false, CheckedVarArgs); 3107 } 3108 } 3109 3110 // For vprintf* functions (i.e., HasVAListArg==true), we add a 3111 // special check to see if the format string is a function parameter 3112 // of the function calling the printf function. If the function 3113 // has an attribute indicating it is a printf-like function, then we 3114 // should suppress warnings concerning non-literals being used in a call 3115 // to a vprintf function. For example: 3116 // 3117 // void 3118 // logmessage(char const *fmt __attribute__ (format (printf, 1, 2)), ...){ 3119 // va_list ap; 3120 // va_start(ap, fmt); 3121 // vprintf(fmt, ap); // Do NOT emit a warning about "fmt". 3122 // ... 3123 // } 3124 if (HasVAListArg) { 3125 if (const ParmVarDecl *PV = dyn_cast<ParmVarDecl>(VD)) { 3126 if (const NamedDecl *ND = dyn_cast<NamedDecl>(PV->getDeclContext())) { 3127 int PVIndex = PV->getFunctionScopeIndex() + 1; 3128 for (const auto *PVFormat : ND->specific_attrs<FormatAttr>()) { 3129 // adjust for implicit parameter 3130 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(ND)) 3131 if (MD->isInstance()) 3132 ++PVIndex; 3133 // We also check if the formats are compatible. 3134 // We can't pass a 'scanf' string to a 'printf' function. 3135 if (PVIndex == PVFormat->getFormatIdx() && 3136 Type == S.GetFormatStringType(PVFormat)) 3137 return SLCT_UncheckedLiteral; 3138 } 3139 } 3140 } 3141 } 3142 } 3143 3144 return SLCT_NotALiteral; 3145 } 3146 3147 case Stmt::CallExprClass: 3148 case Stmt::CXXMemberCallExprClass: { 3149 const CallExpr *CE = cast<CallExpr>(E); 3150 if (const NamedDecl *ND = dyn_cast_or_null<NamedDecl>(CE->getCalleeDecl())) { 3151 if (const FormatArgAttr *FA = ND->getAttr<FormatArgAttr>()) { 3152 unsigned ArgIndex = FA->getFormatIdx(); 3153 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(ND)) 3154 if (MD->isInstance()) 3155 --ArgIndex; 3156 const Expr *Arg = CE->getArg(ArgIndex - 1); 3157 3158 return checkFormatStringExpr(S, Arg, Args, 3159 HasVAListArg, format_idx, firstDataArg, 3160 Type, CallType, InFunctionCall, 3161 CheckedVarArgs); 3162 } else if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND)) { 3163 unsigned BuiltinID = FD->getBuiltinID(); 3164 if (BuiltinID == Builtin::BI__builtin___CFStringMakeConstantString || 3165 BuiltinID == Builtin::BI__builtin___NSStringMakeConstantString) { 3166 const Expr *Arg = CE->getArg(0); 3167 return checkFormatStringExpr(S, Arg, Args, 3168 HasVAListArg, format_idx, 3169 firstDataArg, Type, CallType, 3170 InFunctionCall, CheckedVarArgs); 3171 } 3172 } 3173 } 3174 3175 return SLCT_NotALiteral; 3176 } 3177 case Stmt::ObjCStringLiteralClass: 3178 case Stmt::StringLiteralClass: { 3179 const StringLiteral *StrE = nullptr; 3180 3181 if (const ObjCStringLiteral *ObjCFExpr = dyn_cast<ObjCStringLiteral>(E)) 3182 StrE = ObjCFExpr->getString(); 3183 else 3184 StrE = cast<StringLiteral>(E); 3185 3186 if (StrE) { 3187 S.CheckFormatString(StrE, E, Args, HasVAListArg, format_idx, firstDataArg, 3188 Type, InFunctionCall, CallType, CheckedVarArgs); 3189 return SLCT_CheckedLiteral; 3190 } 3191 3192 return SLCT_NotALiteral; 3193 } 3194 3195 default: 3196 return SLCT_NotALiteral; 3197 } 3198 } 3199 3200 Sema::FormatStringType Sema::GetFormatStringType(const FormatAttr *Format) { 3201 return llvm::StringSwitch<FormatStringType>(Format->getType()->getName()) 3202 .Case("scanf", FST_Scanf) 3203 .Cases("printf", "printf0", FST_Printf) 3204 .Cases("NSString", "CFString", FST_NSString) 3205 .Case("strftime", FST_Strftime) 3206 .Case("strfmon", FST_Strfmon) 3207 .Cases("kprintf", "cmn_err", "vcmn_err", "zcmn_err", FST_Kprintf) 3208 .Case("freebsd_kprintf", FST_FreeBSDKPrintf) 3209 .Case("os_trace", FST_OSTrace) 3210 .Default(FST_Unknown); 3211 } 3212 3213 /// CheckFormatArguments - Check calls to printf and scanf (and similar 3214 /// functions) for correct use of format strings. 3215 /// Returns true if a format string has been fully checked. 3216 bool Sema::CheckFormatArguments(const FormatAttr *Format, 3217 ArrayRef<const Expr *> Args, 3218 bool IsCXXMember, 3219 VariadicCallType CallType, 3220 SourceLocation Loc, SourceRange Range, 3221 llvm::SmallBitVector &CheckedVarArgs) { 3222 FormatStringInfo FSI; 3223 if (getFormatStringInfo(Format, IsCXXMember, &FSI)) 3224 return CheckFormatArguments(Args, FSI.HasVAListArg, FSI.FormatIdx, 3225 FSI.FirstDataArg, GetFormatStringType(Format), 3226 CallType, Loc, Range, CheckedVarArgs); 3227 return false; 3228 } 3229 3230 bool Sema::CheckFormatArguments(ArrayRef<const Expr *> Args, 3231 bool HasVAListArg, unsigned format_idx, 3232 unsigned firstDataArg, FormatStringType Type, 3233 VariadicCallType CallType, 3234 SourceLocation Loc, SourceRange Range, 3235 llvm::SmallBitVector &CheckedVarArgs) { 3236 // CHECK: printf/scanf-like function is called with no format string. 3237 if (format_idx >= Args.size()) { 3238 Diag(Loc, diag::warn_missing_format_string) << Range; 3239 return false; 3240 } 3241 3242 const Expr *OrigFormatExpr = Args[format_idx]->IgnoreParenCasts(); 3243 3244 // CHECK: format string is not a string literal. 3245 // 3246 // Dynamically generated format strings are difficult to 3247 // automatically vet at compile time. Requiring that format strings 3248 // are string literals: (1) permits the checking of format strings by 3249 // the compiler and thereby (2) can practically remove the source of 3250 // many format string exploits. 3251 3252 // Format string can be either ObjC string (e.g. @"%d") or 3253 // C string (e.g. "%d") 3254 // ObjC string uses the same format specifiers as C string, so we can use 3255 // the same format string checking logic for both ObjC and C strings. 3256 StringLiteralCheckType CT = 3257 checkFormatStringExpr(*this, OrigFormatExpr, Args, HasVAListArg, 3258 format_idx, firstDataArg, Type, CallType, 3259 /*IsFunctionCall*/true, CheckedVarArgs); 3260 if (CT != SLCT_NotALiteral) 3261 // Literal format string found, check done! 3262 return CT == SLCT_CheckedLiteral; 3263 3264 // Strftime is particular as it always uses a single 'time' argument, 3265 // so it is safe to pass a non-literal string. 3266 if (Type == FST_Strftime) 3267 return false; 3268 3269 // Do not emit diag when the string param is a macro expansion and the 3270 // format is either NSString or CFString. This is a hack to prevent 3271 // diag when using the NSLocalizedString and CFCopyLocalizedString macros 3272 // which are usually used in place of NS and CF string literals. 3273 if (Type == FST_NSString && 3274 SourceMgr.isInSystemMacro(Args[format_idx]->getLocStart())) 3275 return false; 3276 3277 // If there are no arguments specified, warn with -Wformat-security, otherwise 3278 // warn only with -Wformat-nonliteral. 3279 if (Args.size() == firstDataArg) 3280 Diag(Args[format_idx]->getLocStart(), 3281 diag::warn_format_nonliteral_noargs) 3282 << OrigFormatExpr->getSourceRange(); 3283 else 3284 Diag(Args[format_idx]->getLocStart(), 3285 diag::warn_format_nonliteral) 3286 << OrigFormatExpr->getSourceRange(); 3287 return false; 3288 } 3289 3290 namespace { 3291 class CheckFormatHandler : public analyze_format_string::FormatStringHandler { 3292 protected: 3293 Sema &S; 3294 const StringLiteral *FExpr; 3295 const Expr *OrigFormatExpr; 3296 const unsigned FirstDataArg; 3297 const unsigned NumDataArgs; 3298 const char *Beg; // Start of format string. 3299 const bool HasVAListArg; 3300 ArrayRef<const Expr *> Args; 3301 unsigned FormatIdx; 3302 llvm::SmallBitVector CoveredArgs; 3303 bool usesPositionalArgs; 3304 bool atFirstArg; 3305 bool inFunctionCall; 3306 Sema::VariadicCallType CallType; 3307 llvm::SmallBitVector &CheckedVarArgs; 3308 public: 3309 CheckFormatHandler(Sema &s, const StringLiteral *fexpr, 3310 const Expr *origFormatExpr, unsigned firstDataArg, 3311 unsigned numDataArgs, const char *beg, bool hasVAListArg, 3312 ArrayRef<const Expr *> Args, 3313 unsigned formatIdx, bool inFunctionCall, 3314 Sema::VariadicCallType callType, 3315 llvm::SmallBitVector &CheckedVarArgs) 3316 : S(s), FExpr(fexpr), OrigFormatExpr(origFormatExpr), 3317 FirstDataArg(firstDataArg), NumDataArgs(numDataArgs), 3318 Beg(beg), HasVAListArg(hasVAListArg), 3319 Args(Args), FormatIdx(formatIdx), 3320 usesPositionalArgs(false), atFirstArg(true), 3321 inFunctionCall(inFunctionCall), CallType(callType), 3322 CheckedVarArgs(CheckedVarArgs) { 3323 CoveredArgs.resize(numDataArgs); 3324 CoveredArgs.reset(); 3325 } 3326 3327 void DoneProcessing(); 3328 3329 void HandleIncompleteSpecifier(const char *startSpecifier, 3330 unsigned specifierLen) override; 3331 3332 void HandleInvalidLengthModifier( 3333 const analyze_format_string::FormatSpecifier &FS, 3334 const analyze_format_string::ConversionSpecifier &CS, 3335 const char *startSpecifier, unsigned specifierLen, 3336 unsigned DiagID); 3337 3338 void HandleNonStandardLengthModifier( 3339 const analyze_format_string::FormatSpecifier &FS, 3340 const char *startSpecifier, unsigned specifierLen); 3341 3342 void HandleNonStandardConversionSpecifier( 3343 const analyze_format_string::ConversionSpecifier &CS, 3344 const char *startSpecifier, unsigned specifierLen); 3345 3346 void HandlePosition(const char *startPos, unsigned posLen) override; 3347 3348 void HandleInvalidPosition(const char *startSpecifier, 3349 unsigned specifierLen, 3350 analyze_format_string::PositionContext p) override; 3351 3352 void HandleZeroPosition(const char *startPos, unsigned posLen) override; 3353 3354 void HandleNullChar(const char *nullCharacter) override; 3355 3356 template <typename Range> 3357 static void EmitFormatDiagnostic(Sema &S, bool inFunctionCall, 3358 const Expr *ArgumentExpr, 3359 PartialDiagnostic PDiag, 3360 SourceLocation StringLoc, 3361 bool IsStringLocation, Range StringRange, 3362 ArrayRef<FixItHint> Fixit = None); 3363 3364 protected: 3365 bool HandleInvalidConversionSpecifier(unsigned argIndex, SourceLocation Loc, 3366 const char *startSpec, 3367 unsigned specifierLen, 3368 const char *csStart, unsigned csLen); 3369 3370 void HandlePositionalNonpositionalArgs(SourceLocation Loc, 3371 const char *startSpec, 3372 unsigned specifierLen); 3373 3374 SourceRange getFormatStringRange(); 3375 CharSourceRange getSpecifierRange(const char *startSpecifier, 3376 unsigned specifierLen); 3377 SourceLocation getLocationOfByte(const char *x); 3378 3379 const Expr *getDataArg(unsigned i) const; 3380 3381 bool CheckNumArgs(const analyze_format_string::FormatSpecifier &FS, 3382 const analyze_format_string::ConversionSpecifier &CS, 3383 const char *startSpecifier, unsigned specifierLen, 3384 unsigned argIndex); 3385 3386 template <typename Range> 3387 void EmitFormatDiagnostic(PartialDiagnostic PDiag, SourceLocation StringLoc, 3388 bool IsStringLocation, Range StringRange, 3389 ArrayRef<FixItHint> Fixit = None); 3390 }; 3391 } 3392 3393 SourceRange CheckFormatHandler::getFormatStringRange() { 3394 return OrigFormatExpr->getSourceRange(); 3395 } 3396 3397 CharSourceRange CheckFormatHandler:: 3398 getSpecifierRange(const char *startSpecifier, unsigned specifierLen) { 3399 SourceLocation Start = getLocationOfByte(startSpecifier); 3400 SourceLocation End = getLocationOfByte(startSpecifier + specifierLen - 1); 3401 3402 // Advance the end SourceLocation by one due to half-open ranges. 3403 End = End.getLocWithOffset(1); 3404 3405 return CharSourceRange::getCharRange(Start, End); 3406 } 3407 3408 SourceLocation CheckFormatHandler::getLocationOfByte(const char *x) { 3409 return S.getLocationOfStringLiteralByte(FExpr, x - Beg); 3410 } 3411 3412 void CheckFormatHandler::HandleIncompleteSpecifier(const char *startSpecifier, 3413 unsigned specifierLen){ 3414 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_incomplete_specifier), 3415 getLocationOfByte(startSpecifier), 3416 /*IsStringLocation*/true, 3417 getSpecifierRange(startSpecifier, specifierLen)); 3418 } 3419 3420 void CheckFormatHandler::HandleInvalidLengthModifier( 3421 const analyze_format_string::FormatSpecifier &FS, 3422 const analyze_format_string::ConversionSpecifier &CS, 3423 const char *startSpecifier, unsigned specifierLen, unsigned DiagID) { 3424 using namespace analyze_format_string; 3425 3426 const LengthModifier &LM = FS.getLengthModifier(); 3427 CharSourceRange LMRange = getSpecifierRange(LM.getStart(), LM.getLength()); 3428 3429 // See if we know how to fix this length modifier. 3430 Optional<LengthModifier> FixedLM = FS.getCorrectedLengthModifier(); 3431 if (FixedLM) { 3432 EmitFormatDiagnostic(S.PDiag(DiagID) << LM.toString() << CS.toString(), 3433 getLocationOfByte(LM.getStart()), 3434 /*IsStringLocation*/true, 3435 getSpecifierRange(startSpecifier, specifierLen)); 3436 3437 S.Diag(getLocationOfByte(LM.getStart()), diag::note_format_fix_specifier) 3438 << FixedLM->toString() 3439 << FixItHint::CreateReplacement(LMRange, FixedLM->toString()); 3440 3441 } else { 3442 FixItHint Hint; 3443 if (DiagID == diag::warn_format_nonsensical_length) 3444 Hint = FixItHint::CreateRemoval(LMRange); 3445 3446 EmitFormatDiagnostic(S.PDiag(DiagID) << LM.toString() << CS.toString(), 3447 getLocationOfByte(LM.getStart()), 3448 /*IsStringLocation*/true, 3449 getSpecifierRange(startSpecifier, specifierLen), 3450 Hint); 3451 } 3452 } 3453 3454 void CheckFormatHandler::HandleNonStandardLengthModifier( 3455 const analyze_format_string::FormatSpecifier &FS, 3456 const char *startSpecifier, unsigned specifierLen) { 3457 using namespace analyze_format_string; 3458 3459 const LengthModifier &LM = FS.getLengthModifier(); 3460 CharSourceRange LMRange = getSpecifierRange(LM.getStart(), LM.getLength()); 3461 3462 // See if we know how to fix this length modifier. 3463 Optional<LengthModifier> FixedLM = FS.getCorrectedLengthModifier(); 3464 if (FixedLM) { 3465 EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard) 3466 << LM.toString() << 0, 3467 getLocationOfByte(LM.getStart()), 3468 /*IsStringLocation*/true, 3469 getSpecifierRange(startSpecifier, specifierLen)); 3470 3471 S.Diag(getLocationOfByte(LM.getStart()), diag::note_format_fix_specifier) 3472 << FixedLM->toString() 3473 << FixItHint::CreateReplacement(LMRange, FixedLM->toString()); 3474 3475 } else { 3476 EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard) 3477 << LM.toString() << 0, 3478 getLocationOfByte(LM.getStart()), 3479 /*IsStringLocation*/true, 3480 getSpecifierRange(startSpecifier, specifierLen)); 3481 } 3482 } 3483 3484 void CheckFormatHandler::HandleNonStandardConversionSpecifier( 3485 const analyze_format_string::ConversionSpecifier &CS, 3486 const char *startSpecifier, unsigned specifierLen) { 3487 using namespace analyze_format_string; 3488 3489 // See if we know how to fix this conversion specifier. 3490 Optional<ConversionSpecifier> FixedCS = CS.getStandardSpecifier(); 3491 if (FixedCS) { 3492 EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard) 3493 << CS.toString() << /*conversion specifier*/1, 3494 getLocationOfByte(CS.getStart()), 3495 /*IsStringLocation*/true, 3496 getSpecifierRange(startSpecifier, specifierLen)); 3497 3498 CharSourceRange CSRange = getSpecifierRange(CS.getStart(), CS.getLength()); 3499 S.Diag(getLocationOfByte(CS.getStart()), diag::note_format_fix_specifier) 3500 << FixedCS->toString() 3501 << FixItHint::CreateReplacement(CSRange, FixedCS->toString()); 3502 } else { 3503 EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard) 3504 << CS.toString() << /*conversion specifier*/1, 3505 getLocationOfByte(CS.getStart()), 3506 /*IsStringLocation*/true, 3507 getSpecifierRange(startSpecifier, specifierLen)); 3508 } 3509 } 3510 3511 void CheckFormatHandler::HandlePosition(const char *startPos, 3512 unsigned posLen) { 3513 EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard_positional_arg), 3514 getLocationOfByte(startPos), 3515 /*IsStringLocation*/true, 3516 getSpecifierRange(startPos, posLen)); 3517 } 3518 3519 void 3520 CheckFormatHandler::HandleInvalidPosition(const char *startPos, unsigned posLen, 3521 analyze_format_string::PositionContext p) { 3522 EmitFormatDiagnostic(S.PDiag(diag::warn_format_invalid_positional_specifier) 3523 << (unsigned) p, 3524 getLocationOfByte(startPos), /*IsStringLocation*/true, 3525 getSpecifierRange(startPos, posLen)); 3526 } 3527 3528 void CheckFormatHandler::HandleZeroPosition(const char *startPos, 3529 unsigned posLen) { 3530 EmitFormatDiagnostic(S.PDiag(diag::warn_format_zero_positional_specifier), 3531 getLocationOfByte(startPos), 3532 /*IsStringLocation*/true, 3533 getSpecifierRange(startPos, posLen)); 3534 } 3535 3536 void CheckFormatHandler::HandleNullChar(const char *nullCharacter) { 3537 if (!isa<ObjCStringLiteral>(OrigFormatExpr)) { 3538 // The presence of a null character is likely an error. 3539 EmitFormatDiagnostic( 3540 S.PDiag(diag::warn_printf_format_string_contains_null_char), 3541 getLocationOfByte(nullCharacter), /*IsStringLocation*/true, 3542 getFormatStringRange()); 3543 } 3544 } 3545 3546 // Note that this may return NULL if there was an error parsing or building 3547 // one of the argument expressions. 3548 const Expr *CheckFormatHandler::getDataArg(unsigned i) const { 3549 return Args[FirstDataArg + i]; 3550 } 3551 3552 void CheckFormatHandler::DoneProcessing() { 3553 // Does the number of data arguments exceed the number of 3554 // format conversions in the format string? 3555 if (!HasVAListArg) { 3556 // Find any arguments that weren't covered. 3557 CoveredArgs.flip(); 3558 signed notCoveredArg = CoveredArgs.find_first(); 3559 if (notCoveredArg >= 0) { 3560 assert((unsigned)notCoveredArg < NumDataArgs); 3561 if (const Expr *E = getDataArg((unsigned) notCoveredArg)) { 3562 SourceLocation Loc = E->getLocStart(); 3563 if (!S.getSourceManager().isInSystemMacro(Loc)) { 3564 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_data_arg_not_used), 3565 Loc, /*IsStringLocation*/false, 3566 getFormatStringRange()); 3567 } 3568 } 3569 } 3570 } 3571 } 3572 3573 bool 3574 CheckFormatHandler::HandleInvalidConversionSpecifier(unsigned argIndex, 3575 SourceLocation Loc, 3576 const char *startSpec, 3577 unsigned specifierLen, 3578 const char *csStart, 3579 unsigned csLen) { 3580 3581 bool keepGoing = true; 3582 if (argIndex < NumDataArgs) { 3583 // Consider the argument coverered, even though the specifier doesn't 3584 // make sense. 3585 CoveredArgs.set(argIndex); 3586 } 3587 else { 3588 // If argIndex exceeds the number of data arguments we 3589 // don't issue a warning because that is just a cascade of warnings (and 3590 // they may have intended '%%' anyway). We don't want to continue processing 3591 // the format string after this point, however, as we will like just get 3592 // gibberish when trying to match arguments. 3593 keepGoing = false; 3594 } 3595 3596 EmitFormatDiagnostic(S.PDiag(diag::warn_format_invalid_conversion) 3597 << StringRef(csStart, csLen), 3598 Loc, /*IsStringLocation*/true, 3599 getSpecifierRange(startSpec, specifierLen)); 3600 3601 return keepGoing; 3602 } 3603 3604 void 3605 CheckFormatHandler::HandlePositionalNonpositionalArgs(SourceLocation Loc, 3606 const char *startSpec, 3607 unsigned specifierLen) { 3608 EmitFormatDiagnostic( 3609 S.PDiag(diag::warn_format_mix_positional_nonpositional_args), 3610 Loc, /*isStringLoc*/true, getSpecifierRange(startSpec, specifierLen)); 3611 } 3612 3613 bool 3614 CheckFormatHandler::CheckNumArgs( 3615 const analyze_format_string::FormatSpecifier &FS, 3616 const analyze_format_string::ConversionSpecifier &CS, 3617 const char *startSpecifier, unsigned specifierLen, unsigned argIndex) { 3618 3619 if (argIndex >= NumDataArgs) { 3620 PartialDiagnostic PDiag = FS.usesPositionalArg() 3621 ? (S.PDiag(diag::warn_printf_positional_arg_exceeds_data_args) 3622 << (argIndex+1) << NumDataArgs) 3623 : S.PDiag(diag::warn_printf_insufficient_data_args); 3624 EmitFormatDiagnostic( 3625 PDiag, getLocationOfByte(CS.getStart()), /*IsStringLocation*/true, 3626 getSpecifierRange(startSpecifier, specifierLen)); 3627 return false; 3628 } 3629 return true; 3630 } 3631 3632 template<typename Range> 3633 void CheckFormatHandler::EmitFormatDiagnostic(PartialDiagnostic PDiag, 3634 SourceLocation Loc, 3635 bool IsStringLocation, 3636 Range StringRange, 3637 ArrayRef<FixItHint> FixIt) { 3638 EmitFormatDiagnostic(S, inFunctionCall, Args[FormatIdx], PDiag, 3639 Loc, IsStringLocation, StringRange, FixIt); 3640 } 3641 3642 /// \brief If the format string is not within the funcion call, emit a note 3643 /// so that the function call and string are in diagnostic messages. 3644 /// 3645 /// \param InFunctionCall if true, the format string is within the function 3646 /// call and only one diagnostic message will be produced. Otherwise, an 3647 /// extra note will be emitted pointing to location of the format string. 3648 /// 3649 /// \param ArgumentExpr the expression that is passed as the format string 3650 /// argument in the function call. Used for getting locations when two 3651 /// diagnostics are emitted. 3652 /// 3653 /// \param PDiag the callee should already have provided any strings for the 3654 /// diagnostic message. This function only adds locations and fixits 3655 /// to diagnostics. 3656 /// 3657 /// \param Loc primary location for diagnostic. If two diagnostics are 3658 /// required, one will be at Loc and a new SourceLocation will be created for 3659 /// the other one. 3660 /// 3661 /// \param IsStringLocation if true, Loc points to the format string should be 3662 /// used for the note. Otherwise, Loc points to the argument list and will 3663 /// be used with PDiag. 3664 /// 3665 /// \param StringRange some or all of the string to highlight. This is 3666 /// templated so it can accept either a CharSourceRange or a SourceRange. 3667 /// 3668 /// \param FixIt optional fix it hint for the format string. 3669 template<typename Range> 3670 void CheckFormatHandler::EmitFormatDiagnostic(Sema &S, bool InFunctionCall, 3671 const Expr *ArgumentExpr, 3672 PartialDiagnostic PDiag, 3673 SourceLocation Loc, 3674 bool IsStringLocation, 3675 Range StringRange, 3676 ArrayRef<FixItHint> FixIt) { 3677 if (InFunctionCall) { 3678 const Sema::SemaDiagnosticBuilder &D = S.Diag(Loc, PDiag); 3679 D << StringRange; 3680 D << FixIt; 3681 } else { 3682 S.Diag(IsStringLocation ? ArgumentExpr->getExprLoc() : Loc, PDiag) 3683 << ArgumentExpr->getSourceRange(); 3684 3685 const Sema::SemaDiagnosticBuilder &Note = 3686 S.Diag(IsStringLocation ? Loc : StringRange.getBegin(), 3687 diag::note_format_string_defined); 3688 3689 Note << StringRange; 3690 Note << FixIt; 3691 } 3692 } 3693 3694 //===--- CHECK: Printf format string checking ------------------------------===// 3695 3696 namespace { 3697 class CheckPrintfHandler : public CheckFormatHandler { 3698 bool ObjCContext; 3699 public: 3700 CheckPrintfHandler(Sema &s, const StringLiteral *fexpr, 3701 const Expr *origFormatExpr, unsigned firstDataArg, 3702 unsigned numDataArgs, bool isObjC, 3703 const char *beg, bool hasVAListArg, 3704 ArrayRef<const Expr *> Args, 3705 unsigned formatIdx, bool inFunctionCall, 3706 Sema::VariadicCallType CallType, 3707 llvm::SmallBitVector &CheckedVarArgs) 3708 : CheckFormatHandler(s, fexpr, origFormatExpr, firstDataArg, 3709 numDataArgs, beg, hasVAListArg, Args, 3710 formatIdx, inFunctionCall, CallType, CheckedVarArgs), 3711 ObjCContext(isObjC) 3712 {} 3713 3714 3715 bool HandleInvalidPrintfConversionSpecifier( 3716 const analyze_printf::PrintfSpecifier &FS, 3717 const char *startSpecifier, 3718 unsigned specifierLen) override; 3719 3720 bool HandlePrintfSpecifier(const analyze_printf::PrintfSpecifier &FS, 3721 const char *startSpecifier, 3722 unsigned specifierLen) override; 3723 bool checkFormatExpr(const analyze_printf::PrintfSpecifier &FS, 3724 const char *StartSpecifier, 3725 unsigned SpecifierLen, 3726 const Expr *E); 3727 3728 bool HandleAmount(const analyze_format_string::OptionalAmount &Amt, unsigned k, 3729 const char *startSpecifier, unsigned specifierLen); 3730 void HandleInvalidAmount(const analyze_printf::PrintfSpecifier &FS, 3731 const analyze_printf::OptionalAmount &Amt, 3732 unsigned type, 3733 const char *startSpecifier, unsigned specifierLen); 3734 void HandleFlag(const analyze_printf::PrintfSpecifier &FS, 3735 const analyze_printf::OptionalFlag &flag, 3736 const char *startSpecifier, unsigned specifierLen); 3737 void HandleIgnoredFlag(const analyze_printf::PrintfSpecifier &FS, 3738 const analyze_printf::OptionalFlag &ignoredFlag, 3739 const analyze_printf::OptionalFlag &flag, 3740 const char *startSpecifier, unsigned specifierLen); 3741 bool checkForCStrMembers(const analyze_printf::ArgType &AT, 3742 const Expr *E); 3743 3744 void HandleEmptyObjCModifierFlag(const char *startFlag, 3745 unsigned flagLen) override; 3746 3747 void HandleInvalidObjCModifierFlag(const char *startFlag, 3748 unsigned flagLen) override; 3749 3750 void HandleObjCFlagsWithNonObjCConversion(const char *flagsStart, 3751 const char *flagsEnd, 3752 const char *conversionPosition) 3753 override; 3754 }; 3755 } 3756 3757 bool CheckPrintfHandler::HandleInvalidPrintfConversionSpecifier( 3758 const analyze_printf::PrintfSpecifier &FS, 3759 const char *startSpecifier, 3760 unsigned specifierLen) { 3761 const analyze_printf::PrintfConversionSpecifier &CS = 3762 FS.getConversionSpecifier(); 3763 3764 return HandleInvalidConversionSpecifier(FS.getArgIndex(), 3765 getLocationOfByte(CS.getStart()), 3766 startSpecifier, specifierLen, 3767 CS.getStart(), CS.getLength()); 3768 } 3769 3770 bool CheckPrintfHandler::HandleAmount( 3771 const analyze_format_string::OptionalAmount &Amt, 3772 unsigned k, const char *startSpecifier, 3773 unsigned specifierLen) { 3774 3775 if (Amt.hasDataArgument()) { 3776 if (!HasVAListArg) { 3777 unsigned argIndex = Amt.getArgIndex(); 3778 if (argIndex >= NumDataArgs) { 3779 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_asterisk_missing_arg) 3780 << k, 3781 getLocationOfByte(Amt.getStart()), 3782 /*IsStringLocation*/true, 3783 getSpecifierRange(startSpecifier, specifierLen)); 3784 // Don't do any more checking. We will just emit 3785 // spurious errors. 3786 return false; 3787 } 3788 3789 // Type check the data argument. It should be an 'int'. 3790 // Although not in conformance with C99, we also allow the argument to be 3791 // an 'unsigned int' as that is a reasonably safe case. GCC also 3792 // doesn't emit a warning for that case. 3793 CoveredArgs.set(argIndex); 3794 const Expr *Arg = getDataArg(argIndex); 3795 if (!Arg) 3796 return false; 3797 3798 QualType T = Arg->getType(); 3799 3800 const analyze_printf::ArgType &AT = Amt.getArgType(S.Context); 3801 assert(AT.isValid()); 3802 3803 if (!AT.matchesType(S.Context, T)) { 3804 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_asterisk_wrong_type) 3805 << k << AT.getRepresentativeTypeName(S.Context) 3806 << T << Arg->getSourceRange(), 3807 getLocationOfByte(Amt.getStart()), 3808 /*IsStringLocation*/true, 3809 getSpecifierRange(startSpecifier, specifierLen)); 3810 // Don't do any more checking. We will just emit 3811 // spurious errors. 3812 return false; 3813 } 3814 } 3815 } 3816 return true; 3817 } 3818 3819 void CheckPrintfHandler::HandleInvalidAmount( 3820 const analyze_printf::PrintfSpecifier &FS, 3821 const analyze_printf::OptionalAmount &Amt, 3822 unsigned type, 3823 const char *startSpecifier, 3824 unsigned specifierLen) { 3825 const analyze_printf::PrintfConversionSpecifier &CS = 3826 FS.getConversionSpecifier(); 3827 3828 FixItHint fixit = 3829 Amt.getHowSpecified() == analyze_printf::OptionalAmount::Constant 3830 ? FixItHint::CreateRemoval(getSpecifierRange(Amt.getStart(), 3831 Amt.getConstantLength())) 3832 : FixItHint(); 3833 3834 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_nonsensical_optional_amount) 3835 << type << CS.toString(), 3836 getLocationOfByte(Amt.getStart()), 3837 /*IsStringLocation*/true, 3838 getSpecifierRange(startSpecifier, specifierLen), 3839 fixit); 3840 } 3841 3842 void CheckPrintfHandler::HandleFlag(const analyze_printf::PrintfSpecifier &FS, 3843 const analyze_printf::OptionalFlag &flag, 3844 const char *startSpecifier, 3845 unsigned specifierLen) { 3846 // Warn about pointless flag with a fixit removal. 3847 const analyze_printf::PrintfConversionSpecifier &CS = 3848 FS.getConversionSpecifier(); 3849 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_nonsensical_flag) 3850 << flag.toString() << CS.toString(), 3851 getLocationOfByte(flag.getPosition()), 3852 /*IsStringLocation*/true, 3853 getSpecifierRange(startSpecifier, specifierLen), 3854 FixItHint::CreateRemoval( 3855 getSpecifierRange(flag.getPosition(), 1))); 3856 } 3857 3858 void CheckPrintfHandler::HandleIgnoredFlag( 3859 const analyze_printf::PrintfSpecifier &FS, 3860 const analyze_printf::OptionalFlag &ignoredFlag, 3861 const analyze_printf::OptionalFlag &flag, 3862 const char *startSpecifier, 3863 unsigned specifierLen) { 3864 // Warn about ignored flag with a fixit removal. 3865 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_ignored_flag) 3866 << ignoredFlag.toString() << flag.toString(), 3867 getLocationOfByte(ignoredFlag.getPosition()), 3868 /*IsStringLocation*/true, 3869 getSpecifierRange(startSpecifier, specifierLen), 3870 FixItHint::CreateRemoval( 3871 getSpecifierRange(ignoredFlag.getPosition(), 1))); 3872 } 3873 3874 // void EmitFormatDiagnostic(PartialDiagnostic PDiag, SourceLocation StringLoc, 3875 // bool IsStringLocation, Range StringRange, 3876 // ArrayRef<FixItHint> Fixit = None); 3877 3878 void CheckPrintfHandler::HandleEmptyObjCModifierFlag(const char *startFlag, 3879 unsigned flagLen) { 3880 // Warn about an empty flag. 3881 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_empty_objc_flag), 3882 getLocationOfByte(startFlag), 3883 /*IsStringLocation*/true, 3884 getSpecifierRange(startFlag, flagLen)); 3885 } 3886 3887 void CheckPrintfHandler::HandleInvalidObjCModifierFlag(const char *startFlag, 3888 unsigned flagLen) { 3889 // Warn about an invalid flag. 3890 auto Range = getSpecifierRange(startFlag, flagLen); 3891 StringRef flag(startFlag, flagLen); 3892 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_invalid_objc_flag) << flag, 3893 getLocationOfByte(startFlag), 3894 /*IsStringLocation*/true, 3895 Range, FixItHint::CreateRemoval(Range)); 3896 } 3897 3898 void CheckPrintfHandler::HandleObjCFlagsWithNonObjCConversion( 3899 const char *flagsStart, const char *flagsEnd, const char *conversionPosition) { 3900 // Warn about using '[...]' without a '@' conversion. 3901 auto Range = getSpecifierRange(flagsStart, flagsEnd - flagsStart + 1); 3902 auto diag = diag::warn_printf_ObjCflags_without_ObjCConversion; 3903 EmitFormatDiagnostic(S.PDiag(diag) << StringRef(conversionPosition, 1), 3904 getLocationOfByte(conversionPosition), 3905 /*IsStringLocation*/true, 3906 Range, FixItHint::CreateRemoval(Range)); 3907 } 3908 3909 // Determines if the specified is a C++ class or struct containing 3910 // a member with the specified name and kind (e.g. a CXXMethodDecl named 3911 // "c_str()"). 3912 template<typename MemberKind> 3913 static llvm::SmallPtrSet<MemberKind*, 1> 3914 CXXRecordMembersNamed(StringRef Name, Sema &S, QualType Ty) { 3915 const RecordType *RT = Ty->getAs<RecordType>(); 3916 llvm::SmallPtrSet<MemberKind*, 1> Results; 3917 3918 if (!RT) 3919 return Results; 3920 const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(RT->getDecl()); 3921 if (!RD || !RD->getDefinition()) 3922 return Results; 3923 3924 LookupResult R(S, &S.Context.Idents.get(Name), SourceLocation(), 3925 Sema::LookupMemberName); 3926 R.suppressDiagnostics(); 3927 3928 // We just need to include all members of the right kind turned up by the 3929 // filter, at this point. 3930 if (S.LookupQualifiedName(R, RT->getDecl())) 3931 for (LookupResult::iterator I = R.begin(), E = R.end(); I != E; ++I) { 3932 NamedDecl *decl = (*I)->getUnderlyingDecl(); 3933 if (MemberKind *FK = dyn_cast<MemberKind>(decl)) 3934 Results.insert(FK); 3935 } 3936 return Results; 3937 } 3938 3939 /// Check if we could call '.c_str()' on an object. 3940 /// 3941 /// FIXME: This returns the wrong results in some cases (if cv-qualifiers don't 3942 /// allow the call, or if it would be ambiguous). 3943 bool Sema::hasCStrMethod(const Expr *E) { 3944 typedef llvm::SmallPtrSet<CXXMethodDecl*, 1> MethodSet; 3945 MethodSet Results = 3946 CXXRecordMembersNamed<CXXMethodDecl>("c_str", *this, E->getType()); 3947 for (MethodSet::iterator MI = Results.begin(), ME = Results.end(); 3948 MI != ME; ++MI) 3949 if ((*MI)->getMinRequiredArguments() == 0) 3950 return true; 3951 return false; 3952 } 3953 3954 // Check if a (w)string was passed when a (w)char* was needed, and offer a 3955 // better diagnostic if so. AT is assumed to be valid. 3956 // Returns true when a c_str() conversion method is found. 3957 bool CheckPrintfHandler::checkForCStrMembers( 3958 const analyze_printf::ArgType &AT, const Expr *E) { 3959 typedef llvm::SmallPtrSet<CXXMethodDecl*, 1> MethodSet; 3960 3961 MethodSet Results = 3962 CXXRecordMembersNamed<CXXMethodDecl>("c_str", S, E->getType()); 3963 3964 for (MethodSet::iterator MI = Results.begin(), ME = Results.end(); 3965 MI != ME; ++MI) { 3966 const CXXMethodDecl *Method = *MI; 3967 if (Method->getMinRequiredArguments() == 0 && 3968 AT.matchesType(S.Context, Method->getReturnType())) { 3969 // FIXME: Suggest parens if the expression needs them. 3970 SourceLocation EndLoc = S.getLocForEndOfToken(E->getLocEnd()); 3971 S.Diag(E->getLocStart(), diag::note_printf_c_str) 3972 << "c_str()" 3973 << FixItHint::CreateInsertion(EndLoc, ".c_str()"); 3974 return true; 3975 } 3976 } 3977 3978 return false; 3979 } 3980 3981 bool 3982 CheckPrintfHandler::HandlePrintfSpecifier(const analyze_printf::PrintfSpecifier 3983 &FS, 3984 const char *startSpecifier, 3985 unsigned specifierLen) { 3986 3987 using namespace analyze_format_string; 3988 using namespace analyze_printf; 3989 const PrintfConversionSpecifier &CS = FS.getConversionSpecifier(); 3990 3991 if (FS.consumesDataArgument()) { 3992 if (atFirstArg) { 3993 atFirstArg = false; 3994 usesPositionalArgs = FS.usesPositionalArg(); 3995 } 3996 else if (usesPositionalArgs != FS.usesPositionalArg()) { 3997 HandlePositionalNonpositionalArgs(getLocationOfByte(CS.getStart()), 3998 startSpecifier, specifierLen); 3999 return false; 4000 } 4001 } 4002 4003 // First check if the field width, precision, and conversion specifier 4004 // have matching data arguments. 4005 if (!HandleAmount(FS.getFieldWidth(), /* field width */ 0, 4006 startSpecifier, specifierLen)) { 4007 return false; 4008 } 4009 4010 if (!HandleAmount(FS.getPrecision(), /* precision */ 1, 4011 startSpecifier, specifierLen)) { 4012 return false; 4013 } 4014 4015 if (!CS.consumesDataArgument()) { 4016 // FIXME: Technically specifying a precision or field width here 4017 // makes no sense. Worth issuing a warning at some point. 4018 return true; 4019 } 4020 4021 // Consume the argument. 4022 unsigned argIndex = FS.getArgIndex(); 4023 if (argIndex < NumDataArgs) { 4024 // The check to see if the argIndex is valid will come later. 4025 // We set the bit here because we may exit early from this 4026 // function if we encounter some other error. 4027 CoveredArgs.set(argIndex); 4028 } 4029 4030 // FreeBSD kernel extensions. 4031 if (CS.getKind() == ConversionSpecifier::FreeBSDbArg || 4032 CS.getKind() == ConversionSpecifier::FreeBSDDArg) { 4033 // We need at least two arguments. 4034 if (!CheckNumArgs(FS, CS, startSpecifier, specifierLen, argIndex + 1)) 4035 return false; 4036 4037 // Claim the second argument. 4038 CoveredArgs.set(argIndex + 1); 4039 4040 // Type check the first argument (int for %b, pointer for %D) 4041 const Expr *Ex = getDataArg(argIndex); 4042 const analyze_printf::ArgType &AT = 4043 (CS.getKind() == ConversionSpecifier::FreeBSDbArg) ? 4044 ArgType(S.Context.IntTy) : ArgType::CPointerTy; 4045 if (AT.isValid() && !AT.matchesType(S.Context, Ex->getType())) 4046 EmitFormatDiagnostic( 4047 S.PDiag(diag::warn_format_conversion_argument_type_mismatch) 4048 << AT.getRepresentativeTypeName(S.Context) << Ex->getType() 4049 << false << Ex->getSourceRange(), 4050 Ex->getLocStart(), /*IsStringLocation*/false, 4051 getSpecifierRange(startSpecifier, specifierLen)); 4052 4053 // Type check the second argument (char * for both %b and %D) 4054 Ex = getDataArg(argIndex + 1); 4055 const analyze_printf::ArgType &AT2 = ArgType::CStrTy; 4056 if (AT2.isValid() && !AT2.matchesType(S.Context, Ex->getType())) 4057 EmitFormatDiagnostic( 4058 S.PDiag(diag::warn_format_conversion_argument_type_mismatch) 4059 << AT2.getRepresentativeTypeName(S.Context) << Ex->getType() 4060 << false << Ex->getSourceRange(), 4061 Ex->getLocStart(), /*IsStringLocation*/false, 4062 getSpecifierRange(startSpecifier, specifierLen)); 4063 4064 return true; 4065 } 4066 4067 // Check for using an Objective-C specific conversion specifier 4068 // in a non-ObjC literal. 4069 if (!ObjCContext && CS.isObjCArg()) { 4070 return HandleInvalidPrintfConversionSpecifier(FS, startSpecifier, 4071 specifierLen); 4072 } 4073 4074 // Check for invalid use of field width 4075 if (!FS.hasValidFieldWidth()) { 4076 HandleInvalidAmount(FS, FS.getFieldWidth(), /* field width */ 0, 4077 startSpecifier, specifierLen); 4078 } 4079 4080 // Check for invalid use of precision 4081 if (!FS.hasValidPrecision()) { 4082 HandleInvalidAmount(FS, FS.getPrecision(), /* precision */ 1, 4083 startSpecifier, specifierLen); 4084 } 4085 4086 // Check each flag does not conflict with any other component. 4087 if (!FS.hasValidThousandsGroupingPrefix()) 4088 HandleFlag(FS, FS.hasThousandsGrouping(), startSpecifier, specifierLen); 4089 if (!FS.hasValidLeadingZeros()) 4090 HandleFlag(FS, FS.hasLeadingZeros(), startSpecifier, specifierLen); 4091 if (!FS.hasValidPlusPrefix()) 4092 HandleFlag(FS, FS.hasPlusPrefix(), startSpecifier, specifierLen); 4093 if (!FS.hasValidSpacePrefix()) 4094 HandleFlag(FS, FS.hasSpacePrefix(), startSpecifier, specifierLen); 4095 if (!FS.hasValidAlternativeForm()) 4096 HandleFlag(FS, FS.hasAlternativeForm(), startSpecifier, specifierLen); 4097 if (!FS.hasValidLeftJustified()) 4098 HandleFlag(FS, FS.isLeftJustified(), startSpecifier, specifierLen); 4099 4100 // Check that flags are not ignored by another flag 4101 if (FS.hasSpacePrefix() && FS.hasPlusPrefix()) // ' ' ignored by '+' 4102 HandleIgnoredFlag(FS, FS.hasSpacePrefix(), FS.hasPlusPrefix(), 4103 startSpecifier, specifierLen); 4104 if (FS.hasLeadingZeros() && FS.isLeftJustified()) // '0' ignored by '-' 4105 HandleIgnoredFlag(FS, FS.hasLeadingZeros(), FS.isLeftJustified(), 4106 startSpecifier, specifierLen); 4107 4108 // Check the length modifier is valid with the given conversion specifier. 4109 if (!FS.hasValidLengthModifier(S.getASTContext().getTargetInfo())) 4110 HandleInvalidLengthModifier(FS, CS, startSpecifier, specifierLen, 4111 diag::warn_format_nonsensical_length); 4112 else if (!FS.hasStandardLengthModifier()) 4113 HandleNonStandardLengthModifier(FS, startSpecifier, specifierLen); 4114 else if (!FS.hasStandardLengthConversionCombination()) 4115 HandleInvalidLengthModifier(FS, CS, startSpecifier, specifierLen, 4116 diag::warn_format_non_standard_conversion_spec); 4117 4118 if (!FS.hasStandardConversionSpecifier(S.getLangOpts())) 4119 HandleNonStandardConversionSpecifier(CS, startSpecifier, specifierLen); 4120 4121 // The remaining checks depend on the data arguments. 4122 if (HasVAListArg) 4123 return true; 4124 4125 if (!CheckNumArgs(FS, CS, startSpecifier, specifierLen, argIndex)) 4126 return false; 4127 4128 const Expr *Arg = getDataArg(argIndex); 4129 if (!Arg) 4130 return true; 4131 4132 return checkFormatExpr(FS, startSpecifier, specifierLen, Arg); 4133 } 4134 4135 static bool requiresParensToAddCast(const Expr *E) { 4136 // FIXME: We should have a general way to reason about operator 4137 // precedence and whether parens are actually needed here. 4138 // Take care of a few common cases where they aren't. 4139 const Expr *Inside = E->IgnoreImpCasts(); 4140 if (const PseudoObjectExpr *POE = dyn_cast<PseudoObjectExpr>(Inside)) 4141 Inside = POE->getSyntacticForm()->IgnoreImpCasts(); 4142 4143 switch (Inside->getStmtClass()) { 4144 case Stmt::ArraySubscriptExprClass: 4145 case Stmt::CallExprClass: 4146 case Stmt::CharacterLiteralClass: 4147 case Stmt::CXXBoolLiteralExprClass: 4148 case Stmt::DeclRefExprClass: 4149 case Stmt::FloatingLiteralClass: 4150 case Stmt::IntegerLiteralClass: 4151 case Stmt::MemberExprClass: 4152 case Stmt::ObjCArrayLiteralClass: 4153 case Stmt::ObjCBoolLiteralExprClass: 4154 case Stmt::ObjCBoxedExprClass: 4155 case Stmt::ObjCDictionaryLiteralClass: 4156 case Stmt::ObjCEncodeExprClass: 4157 case Stmt::ObjCIvarRefExprClass: 4158 case Stmt::ObjCMessageExprClass: 4159 case Stmt::ObjCPropertyRefExprClass: 4160 case Stmt::ObjCStringLiteralClass: 4161 case Stmt::ObjCSubscriptRefExprClass: 4162 case Stmt::ParenExprClass: 4163 case Stmt::StringLiteralClass: 4164 case Stmt::UnaryOperatorClass: 4165 return false; 4166 default: 4167 return true; 4168 } 4169 } 4170 4171 static std::pair<QualType, StringRef> 4172 shouldNotPrintDirectly(const ASTContext &Context, 4173 QualType IntendedTy, 4174 const Expr *E) { 4175 // Use a 'while' to peel off layers of typedefs. 4176 QualType TyTy = IntendedTy; 4177 while (const TypedefType *UserTy = TyTy->getAs<TypedefType>()) { 4178 StringRef Name = UserTy->getDecl()->getName(); 4179 QualType CastTy = llvm::StringSwitch<QualType>(Name) 4180 .Case("NSInteger", Context.LongTy) 4181 .Case("NSUInteger", Context.UnsignedLongTy) 4182 .Case("SInt32", Context.IntTy) 4183 .Case("UInt32", Context.UnsignedIntTy) 4184 .Default(QualType()); 4185 4186 if (!CastTy.isNull()) 4187 return std::make_pair(CastTy, Name); 4188 4189 TyTy = UserTy->desugar(); 4190 } 4191 4192 // Strip parens if necessary. 4193 if (const ParenExpr *PE = dyn_cast<ParenExpr>(E)) 4194 return shouldNotPrintDirectly(Context, 4195 PE->getSubExpr()->getType(), 4196 PE->getSubExpr()); 4197 4198 // If this is a conditional expression, then its result type is constructed 4199 // via usual arithmetic conversions and thus there might be no necessary 4200 // typedef sugar there. Recurse to operands to check for NSInteger & 4201 // Co. usage condition. 4202 if (const ConditionalOperator *CO = dyn_cast<ConditionalOperator>(E)) { 4203 QualType TrueTy, FalseTy; 4204 StringRef TrueName, FalseName; 4205 4206 std::tie(TrueTy, TrueName) = 4207 shouldNotPrintDirectly(Context, 4208 CO->getTrueExpr()->getType(), 4209 CO->getTrueExpr()); 4210 std::tie(FalseTy, FalseName) = 4211 shouldNotPrintDirectly(Context, 4212 CO->getFalseExpr()->getType(), 4213 CO->getFalseExpr()); 4214 4215 if (TrueTy == FalseTy) 4216 return std::make_pair(TrueTy, TrueName); 4217 else if (TrueTy.isNull()) 4218 return std::make_pair(FalseTy, FalseName); 4219 else if (FalseTy.isNull()) 4220 return std::make_pair(TrueTy, TrueName); 4221 } 4222 4223 return std::make_pair(QualType(), StringRef()); 4224 } 4225 4226 bool 4227 CheckPrintfHandler::checkFormatExpr(const analyze_printf::PrintfSpecifier &FS, 4228 const char *StartSpecifier, 4229 unsigned SpecifierLen, 4230 const Expr *E) { 4231 using namespace analyze_format_string; 4232 using namespace analyze_printf; 4233 // Now type check the data expression that matches the 4234 // format specifier. 4235 const analyze_printf::ArgType &AT = FS.getArgType(S.Context, 4236 ObjCContext); 4237 if (!AT.isValid()) 4238 return true; 4239 4240 QualType ExprTy = E->getType(); 4241 while (const TypeOfExprType *TET = dyn_cast<TypeOfExprType>(ExprTy)) { 4242 ExprTy = TET->getUnderlyingExpr()->getType(); 4243 } 4244 4245 analyze_printf::ArgType::MatchKind match = AT.matchesType(S.Context, ExprTy); 4246 4247 if (match == analyze_printf::ArgType::Match) { 4248 return true; 4249 } 4250 4251 // Look through argument promotions for our error message's reported type. 4252 // This includes the integral and floating promotions, but excludes array 4253 // and function pointer decay; seeing that an argument intended to be a 4254 // string has type 'char [6]' is probably more confusing than 'char *'. 4255 if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) { 4256 if (ICE->getCastKind() == CK_IntegralCast || 4257 ICE->getCastKind() == CK_FloatingCast) { 4258 E = ICE->getSubExpr(); 4259 ExprTy = E->getType(); 4260 4261 // Check if we didn't match because of an implicit cast from a 'char' 4262 // or 'short' to an 'int'. This is done because printf is a varargs 4263 // function. 4264 if (ICE->getType() == S.Context.IntTy || 4265 ICE->getType() == S.Context.UnsignedIntTy) { 4266 // All further checking is done on the subexpression. 4267 if (AT.matchesType(S.Context, ExprTy)) 4268 return true; 4269 } 4270 } 4271 } else if (const CharacterLiteral *CL = dyn_cast<CharacterLiteral>(E)) { 4272 // Special case for 'a', which has type 'int' in C. 4273 // Note, however, that we do /not/ want to treat multibyte constants like 4274 // 'MooV' as characters! This form is deprecated but still exists. 4275 if (ExprTy == S.Context.IntTy) 4276 if (llvm::isUIntN(S.Context.getCharWidth(), CL->getValue())) 4277 ExprTy = S.Context.CharTy; 4278 } 4279 4280 // Look through enums to their underlying type. 4281 bool IsEnum = false; 4282 if (auto EnumTy = ExprTy->getAs<EnumType>()) { 4283 ExprTy = EnumTy->getDecl()->getIntegerType(); 4284 IsEnum = true; 4285 } 4286 4287 // %C in an Objective-C context prints a unichar, not a wchar_t. 4288 // If the argument is an integer of some kind, believe the %C and suggest 4289 // a cast instead of changing the conversion specifier. 4290 QualType IntendedTy = ExprTy; 4291 if (ObjCContext && 4292 FS.getConversionSpecifier().getKind() == ConversionSpecifier::CArg) { 4293 if (ExprTy->isIntegralOrUnscopedEnumerationType() && 4294 !ExprTy->isCharType()) { 4295 // 'unichar' is defined as a typedef of unsigned short, but we should 4296 // prefer using the typedef if it is visible. 4297 IntendedTy = S.Context.UnsignedShortTy; 4298 4299 // While we are here, check if the value is an IntegerLiteral that happens 4300 // to be within the valid range. 4301 if (const IntegerLiteral *IL = dyn_cast<IntegerLiteral>(E)) { 4302 const llvm::APInt &V = IL->getValue(); 4303 if (V.getActiveBits() <= S.Context.getTypeSize(IntendedTy)) 4304 return true; 4305 } 4306 4307 LookupResult Result(S, &S.Context.Idents.get("unichar"), E->getLocStart(), 4308 Sema::LookupOrdinaryName); 4309 if (S.LookupName(Result, S.getCurScope())) { 4310 NamedDecl *ND = Result.getFoundDecl(); 4311 if (TypedefNameDecl *TD = dyn_cast<TypedefNameDecl>(ND)) 4312 if (TD->getUnderlyingType() == IntendedTy) 4313 IntendedTy = S.Context.getTypedefType(TD); 4314 } 4315 } 4316 } 4317 4318 // Special-case some of Darwin's platform-independence types by suggesting 4319 // casts to primitive types that are known to be large enough. 4320 bool ShouldNotPrintDirectly = false; StringRef CastTyName; 4321 if (S.Context.getTargetInfo().getTriple().isOSDarwin()) { 4322 QualType CastTy; 4323 std::tie(CastTy, CastTyName) = shouldNotPrintDirectly(S.Context, IntendedTy, E); 4324 if (!CastTy.isNull()) { 4325 IntendedTy = CastTy; 4326 ShouldNotPrintDirectly = true; 4327 } 4328 } 4329 4330 // We may be able to offer a FixItHint if it is a supported type. 4331 PrintfSpecifier fixedFS = FS; 4332 bool success = fixedFS.fixType(IntendedTy, S.getLangOpts(), 4333 S.Context, ObjCContext); 4334 4335 if (success) { 4336 // Get the fix string from the fixed format specifier 4337 SmallString<16> buf; 4338 llvm::raw_svector_ostream os(buf); 4339 fixedFS.toString(os); 4340 4341 CharSourceRange SpecRange = getSpecifierRange(StartSpecifier, SpecifierLen); 4342 4343 if (IntendedTy == ExprTy && !ShouldNotPrintDirectly) { 4344 unsigned diag = diag::warn_format_conversion_argument_type_mismatch; 4345 if (match == analyze_format_string::ArgType::NoMatchPedantic) { 4346 diag = diag::warn_format_conversion_argument_type_mismatch_pedantic; 4347 } 4348 // In this case, the specifier is wrong and should be changed to match 4349 // the argument. 4350 EmitFormatDiagnostic(S.PDiag(diag) 4351 << AT.getRepresentativeTypeName(S.Context) 4352 << IntendedTy << IsEnum << E->getSourceRange(), 4353 E->getLocStart(), 4354 /*IsStringLocation*/ false, SpecRange, 4355 FixItHint::CreateReplacement(SpecRange, os.str())); 4356 4357 } else { 4358 // The canonical type for formatting this value is different from the 4359 // actual type of the expression. (This occurs, for example, with Darwin's 4360 // NSInteger on 32-bit platforms, where it is typedef'd as 'int', but 4361 // should be printed as 'long' for 64-bit compatibility.) 4362 // Rather than emitting a normal format/argument mismatch, we want to 4363 // add a cast to the recommended type (and correct the format string 4364 // if necessary). 4365 SmallString<16> CastBuf; 4366 llvm::raw_svector_ostream CastFix(CastBuf); 4367 CastFix << "("; 4368 IntendedTy.print(CastFix, S.Context.getPrintingPolicy()); 4369 CastFix << ")"; 4370 4371 SmallVector<FixItHint,4> Hints; 4372 if (!AT.matchesType(S.Context, IntendedTy)) 4373 Hints.push_back(FixItHint::CreateReplacement(SpecRange, os.str())); 4374 4375 if (const CStyleCastExpr *CCast = dyn_cast<CStyleCastExpr>(E)) { 4376 // If there's already a cast present, just replace it. 4377 SourceRange CastRange(CCast->getLParenLoc(), CCast->getRParenLoc()); 4378 Hints.push_back(FixItHint::CreateReplacement(CastRange, CastFix.str())); 4379 4380 } else if (!requiresParensToAddCast(E)) { 4381 // If the expression has high enough precedence, 4382 // just write the C-style cast. 4383 Hints.push_back(FixItHint::CreateInsertion(E->getLocStart(), 4384 CastFix.str())); 4385 } else { 4386 // Otherwise, add parens around the expression as well as the cast. 4387 CastFix << "("; 4388 Hints.push_back(FixItHint::CreateInsertion(E->getLocStart(), 4389 CastFix.str())); 4390 4391 SourceLocation After = S.getLocForEndOfToken(E->getLocEnd()); 4392 Hints.push_back(FixItHint::CreateInsertion(After, ")")); 4393 } 4394 4395 if (ShouldNotPrintDirectly) { 4396 // The expression has a type that should not be printed directly. 4397 // We extract the name from the typedef because we don't want to show 4398 // the underlying type in the diagnostic. 4399 StringRef Name; 4400 if (const TypedefType *TypedefTy = dyn_cast<TypedefType>(ExprTy)) 4401 Name = TypedefTy->getDecl()->getName(); 4402 else 4403 Name = CastTyName; 4404 EmitFormatDiagnostic(S.PDiag(diag::warn_format_argument_needs_cast) 4405 << Name << IntendedTy << IsEnum 4406 << E->getSourceRange(), 4407 E->getLocStart(), /*IsStringLocation=*/false, 4408 SpecRange, Hints); 4409 } else { 4410 // In this case, the expression could be printed using a different 4411 // specifier, but we've decided that the specifier is probably correct 4412 // and we should cast instead. Just use the normal warning message. 4413 EmitFormatDiagnostic( 4414 S.PDiag(diag::warn_format_conversion_argument_type_mismatch) 4415 << AT.getRepresentativeTypeName(S.Context) << ExprTy << IsEnum 4416 << E->getSourceRange(), 4417 E->getLocStart(), /*IsStringLocation*/false, 4418 SpecRange, Hints); 4419 } 4420 } 4421 } else { 4422 const CharSourceRange &CSR = getSpecifierRange(StartSpecifier, 4423 SpecifierLen); 4424 // Since the warning for passing non-POD types to variadic functions 4425 // was deferred until now, we emit a warning for non-POD 4426 // arguments here. 4427 switch (S.isValidVarArgType(ExprTy)) { 4428 case Sema::VAK_Valid: 4429 case Sema::VAK_ValidInCXX11: { 4430 unsigned diag = diag::warn_format_conversion_argument_type_mismatch; 4431 if (match == analyze_printf::ArgType::NoMatchPedantic) { 4432 diag = diag::warn_format_conversion_argument_type_mismatch_pedantic; 4433 } 4434 4435 EmitFormatDiagnostic( 4436 S.PDiag(diag) << AT.getRepresentativeTypeName(S.Context) << ExprTy 4437 << IsEnum << CSR << E->getSourceRange(), 4438 E->getLocStart(), /*IsStringLocation*/ false, CSR); 4439 break; 4440 } 4441 case Sema::VAK_Undefined: 4442 case Sema::VAK_MSVCUndefined: 4443 EmitFormatDiagnostic( 4444 S.PDiag(diag::warn_non_pod_vararg_with_format_string) 4445 << S.getLangOpts().CPlusPlus11 4446 << ExprTy 4447 << CallType 4448 << AT.getRepresentativeTypeName(S.Context) 4449 << CSR 4450 << E->getSourceRange(), 4451 E->getLocStart(), /*IsStringLocation*/false, CSR); 4452 checkForCStrMembers(AT, E); 4453 break; 4454 4455 case Sema::VAK_Invalid: 4456 if (ExprTy->isObjCObjectType()) 4457 EmitFormatDiagnostic( 4458 S.PDiag(diag::err_cannot_pass_objc_interface_to_vararg_format) 4459 << S.getLangOpts().CPlusPlus11 4460 << ExprTy 4461 << CallType 4462 << AT.getRepresentativeTypeName(S.Context) 4463 << CSR 4464 << E->getSourceRange(), 4465 E->getLocStart(), /*IsStringLocation*/false, CSR); 4466 else 4467 // FIXME: If this is an initializer list, suggest removing the braces 4468 // or inserting a cast to the target type. 4469 S.Diag(E->getLocStart(), diag::err_cannot_pass_to_vararg_format) 4470 << isa<InitListExpr>(E) << ExprTy << CallType 4471 << AT.getRepresentativeTypeName(S.Context) 4472 << E->getSourceRange(); 4473 break; 4474 } 4475 4476 assert(FirstDataArg + FS.getArgIndex() < CheckedVarArgs.size() && 4477 "format string specifier index out of range"); 4478 CheckedVarArgs[FirstDataArg + FS.getArgIndex()] = true; 4479 } 4480 4481 return true; 4482 } 4483 4484 //===--- CHECK: Scanf format string checking ------------------------------===// 4485 4486 namespace { 4487 class CheckScanfHandler : public CheckFormatHandler { 4488 public: 4489 CheckScanfHandler(Sema &s, const StringLiteral *fexpr, 4490 const Expr *origFormatExpr, unsigned firstDataArg, 4491 unsigned numDataArgs, const char *beg, bool hasVAListArg, 4492 ArrayRef<const Expr *> Args, 4493 unsigned formatIdx, bool inFunctionCall, 4494 Sema::VariadicCallType CallType, 4495 llvm::SmallBitVector &CheckedVarArgs) 4496 : CheckFormatHandler(s, fexpr, origFormatExpr, firstDataArg, 4497 numDataArgs, beg, hasVAListArg, 4498 Args, formatIdx, inFunctionCall, CallType, 4499 CheckedVarArgs) 4500 {} 4501 4502 bool HandleScanfSpecifier(const analyze_scanf::ScanfSpecifier &FS, 4503 const char *startSpecifier, 4504 unsigned specifierLen) override; 4505 4506 bool HandleInvalidScanfConversionSpecifier( 4507 const analyze_scanf::ScanfSpecifier &FS, 4508 const char *startSpecifier, 4509 unsigned specifierLen) override; 4510 4511 void HandleIncompleteScanList(const char *start, const char *end) override; 4512 }; 4513 } 4514 4515 void CheckScanfHandler::HandleIncompleteScanList(const char *start, 4516 const char *end) { 4517 EmitFormatDiagnostic(S.PDiag(diag::warn_scanf_scanlist_incomplete), 4518 getLocationOfByte(end), /*IsStringLocation*/true, 4519 getSpecifierRange(start, end - start)); 4520 } 4521 4522 bool CheckScanfHandler::HandleInvalidScanfConversionSpecifier( 4523 const analyze_scanf::ScanfSpecifier &FS, 4524 const char *startSpecifier, 4525 unsigned specifierLen) { 4526 4527 const analyze_scanf::ScanfConversionSpecifier &CS = 4528 FS.getConversionSpecifier(); 4529 4530 return HandleInvalidConversionSpecifier(FS.getArgIndex(), 4531 getLocationOfByte(CS.getStart()), 4532 startSpecifier, specifierLen, 4533 CS.getStart(), CS.getLength()); 4534 } 4535 4536 bool CheckScanfHandler::HandleScanfSpecifier( 4537 const analyze_scanf::ScanfSpecifier &FS, 4538 const char *startSpecifier, 4539 unsigned specifierLen) { 4540 4541 using namespace analyze_scanf; 4542 using namespace analyze_format_string; 4543 4544 const ScanfConversionSpecifier &CS = FS.getConversionSpecifier(); 4545 4546 // Handle case where '%' and '*' don't consume an argument. These shouldn't 4547 // be used to decide if we are using positional arguments consistently. 4548 if (FS.consumesDataArgument()) { 4549 if (atFirstArg) { 4550 atFirstArg = false; 4551 usesPositionalArgs = FS.usesPositionalArg(); 4552 } 4553 else if (usesPositionalArgs != FS.usesPositionalArg()) { 4554 HandlePositionalNonpositionalArgs(getLocationOfByte(CS.getStart()), 4555 startSpecifier, specifierLen); 4556 return false; 4557 } 4558 } 4559 4560 // Check if the field with is non-zero. 4561 const OptionalAmount &Amt = FS.getFieldWidth(); 4562 if (Amt.getHowSpecified() == OptionalAmount::Constant) { 4563 if (Amt.getConstantAmount() == 0) { 4564 const CharSourceRange &R = getSpecifierRange(Amt.getStart(), 4565 Amt.getConstantLength()); 4566 EmitFormatDiagnostic(S.PDiag(diag::warn_scanf_nonzero_width), 4567 getLocationOfByte(Amt.getStart()), 4568 /*IsStringLocation*/true, R, 4569 FixItHint::CreateRemoval(R)); 4570 } 4571 } 4572 4573 if (!FS.consumesDataArgument()) { 4574 // FIXME: Technically specifying a precision or field width here 4575 // makes no sense. Worth issuing a warning at some point. 4576 return true; 4577 } 4578 4579 // Consume the argument. 4580 unsigned argIndex = FS.getArgIndex(); 4581 if (argIndex < NumDataArgs) { 4582 // The check to see if the argIndex is valid will come later. 4583 // We set the bit here because we may exit early from this 4584 // function if we encounter some other error. 4585 CoveredArgs.set(argIndex); 4586 } 4587 4588 // Check the length modifier is valid with the given conversion specifier. 4589 if (!FS.hasValidLengthModifier(S.getASTContext().getTargetInfo())) 4590 HandleInvalidLengthModifier(FS, CS, startSpecifier, specifierLen, 4591 diag::warn_format_nonsensical_length); 4592 else if (!FS.hasStandardLengthModifier()) 4593 HandleNonStandardLengthModifier(FS, startSpecifier, specifierLen); 4594 else if (!FS.hasStandardLengthConversionCombination()) 4595 HandleInvalidLengthModifier(FS, CS, startSpecifier, specifierLen, 4596 diag::warn_format_non_standard_conversion_spec); 4597 4598 if (!FS.hasStandardConversionSpecifier(S.getLangOpts())) 4599 HandleNonStandardConversionSpecifier(CS, startSpecifier, specifierLen); 4600 4601 // The remaining checks depend on the data arguments. 4602 if (HasVAListArg) 4603 return true; 4604 4605 if (!CheckNumArgs(FS, CS, startSpecifier, specifierLen, argIndex)) 4606 return false; 4607 4608 // Check that the argument type matches the format specifier. 4609 const Expr *Ex = getDataArg(argIndex); 4610 if (!Ex) 4611 return true; 4612 4613 const analyze_format_string::ArgType &AT = FS.getArgType(S.Context); 4614 4615 if (!AT.isValid()) { 4616 return true; 4617 } 4618 4619 analyze_format_string::ArgType::MatchKind match = 4620 AT.matchesType(S.Context, Ex->getType()); 4621 if (match == analyze_format_string::ArgType::Match) { 4622 return true; 4623 } 4624 4625 ScanfSpecifier fixedFS = FS; 4626 bool success = fixedFS.fixType(Ex->getType(), Ex->IgnoreImpCasts()->getType(), 4627 S.getLangOpts(), S.Context); 4628 4629 unsigned diag = diag::warn_format_conversion_argument_type_mismatch; 4630 if (match == analyze_format_string::ArgType::NoMatchPedantic) { 4631 diag = diag::warn_format_conversion_argument_type_mismatch_pedantic; 4632 } 4633 4634 if (success) { 4635 // Get the fix string from the fixed format specifier. 4636 SmallString<128> buf; 4637 llvm::raw_svector_ostream os(buf); 4638 fixedFS.toString(os); 4639 4640 EmitFormatDiagnostic( 4641 S.PDiag(diag) << AT.getRepresentativeTypeName(S.Context) 4642 << Ex->getType() << false << Ex->getSourceRange(), 4643 Ex->getLocStart(), 4644 /*IsStringLocation*/ false, 4645 getSpecifierRange(startSpecifier, specifierLen), 4646 FixItHint::CreateReplacement( 4647 getSpecifierRange(startSpecifier, specifierLen), os.str())); 4648 } else { 4649 EmitFormatDiagnostic(S.PDiag(diag) 4650 << AT.getRepresentativeTypeName(S.Context) 4651 << Ex->getType() << false << Ex->getSourceRange(), 4652 Ex->getLocStart(), 4653 /*IsStringLocation*/ false, 4654 getSpecifierRange(startSpecifier, specifierLen)); 4655 } 4656 4657 return true; 4658 } 4659 4660 void Sema::CheckFormatString(const StringLiteral *FExpr, 4661 const Expr *OrigFormatExpr, 4662 ArrayRef<const Expr *> Args, 4663 bool HasVAListArg, unsigned format_idx, 4664 unsigned firstDataArg, FormatStringType Type, 4665 bool inFunctionCall, VariadicCallType CallType, 4666 llvm::SmallBitVector &CheckedVarArgs) { 4667 4668 // CHECK: is the format string a wide literal? 4669 if (!FExpr->isAscii() && !FExpr->isUTF8()) { 4670 CheckFormatHandler::EmitFormatDiagnostic( 4671 *this, inFunctionCall, Args[format_idx], 4672 PDiag(diag::warn_format_string_is_wide_literal), FExpr->getLocStart(), 4673 /*IsStringLocation*/true, OrigFormatExpr->getSourceRange()); 4674 return; 4675 } 4676 4677 // Str - The format string. NOTE: this is NOT null-terminated! 4678 StringRef StrRef = FExpr->getString(); 4679 const char *Str = StrRef.data(); 4680 // Account for cases where the string literal is truncated in a declaration. 4681 const ConstantArrayType *T = Context.getAsConstantArrayType(FExpr->getType()); 4682 assert(T && "String literal not of constant array type!"); 4683 size_t TypeSize = T->getSize().getZExtValue(); 4684 size_t StrLen = std::min(std::max(TypeSize, size_t(1)) - 1, StrRef.size()); 4685 const unsigned numDataArgs = Args.size() - firstDataArg; 4686 4687 // Emit a warning if the string literal is truncated and does not contain an 4688 // embedded null character. 4689 if (TypeSize <= StrRef.size() && 4690 StrRef.substr(0, TypeSize).find('\0') == StringRef::npos) { 4691 CheckFormatHandler::EmitFormatDiagnostic( 4692 *this, inFunctionCall, Args[format_idx], 4693 PDiag(diag::warn_printf_format_string_not_null_terminated), 4694 FExpr->getLocStart(), 4695 /*IsStringLocation=*/true, OrigFormatExpr->getSourceRange()); 4696 return; 4697 } 4698 4699 // CHECK: empty format string? 4700 if (StrLen == 0 && numDataArgs > 0) { 4701 CheckFormatHandler::EmitFormatDiagnostic( 4702 *this, inFunctionCall, Args[format_idx], 4703 PDiag(diag::warn_empty_format_string), FExpr->getLocStart(), 4704 /*IsStringLocation*/true, OrigFormatExpr->getSourceRange()); 4705 return; 4706 } 4707 4708 if (Type == FST_Printf || Type == FST_NSString || 4709 Type == FST_FreeBSDKPrintf || Type == FST_OSTrace) { 4710 CheckPrintfHandler H(*this, FExpr, OrigFormatExpr, firstDataArg, 4711 numDataArgs, (Type == FST_NSString || Type == FST_OSTrace), 4712 Str, HasVAListArg, Args, format_idx, 4713 inFunctionCall, CallType, CheckedVarArgs); 4714 4715 if (!analyze_format_string::ParsePrintfString(H, Str, Str + StrLen, 4716 getLangOpts(), 4717 Context.getTargetInfo(), 4718 Type == FST_FreeBSDKPrintf)) 4719 H.DoneProcessing(); 4720 } else if (Type == FST_Scanf) { 4721 CheckScanfHandler H(*this, FExpr, OrigFormatExpr, firstDataArg, numDataArgs, 4722 Str, HasVAListArg, Args, format_idx, 4723 inFunctionCall, CallType, CheckedVarArgs); 4724 4725 if (!analyze_format_string::ParseScanfString(H, Str, Str + StrLen, 4726 getLangOpts(), 4727 Context.getTargetInfo())) 4728 H.DoneProcessing(); 4729 } // TODO: handle other formats 4730 } 4731 4732 bool Sema::FormatStringHasSArg(const StringLiteral *FExpr) { 4733 // Str - The format string. NOTE: this is NOT null-terminated! 4734 StringRef StrRef = FExpr->getString(); 4735 const char *Str = StrRef.data(); 4736 // Account for cases where the string literal is truncated in a declaration. 4737 const ConstantArrayType *T = Context.getAsConstantArrayType(FExpr->getType()); 4738 assert(T && "String literal not of constant array type!"); 4739 size_t TypeSize = T->getSize().getZExtValue(); 4740 size_t StrLen = std::min(std::max(TypeSize, size_t(1)) - 1, StrRef.size()); 4741 return analyze_format_string::ParseFormatStringHasSArg(Str, Str + StrLen, 4742 getLangOpts(), 4743 Context.getTargetInfo()); 4744 } 4745 4746 //===--- CHECK: Warn on use of wrong absolute value function. -------------===// 4747 4748 // Returns the related absolute value function that is larger, of 0 if one 4749 // does not exist. 4750 static unsigned getLargerAbsoluteValueFunction(unsigned AbsFunction) { 4751 switch (AbsFunction) { 4752 default: 4753 return 0; 4754 4755 case Builtin::BI__builtin_abs: 4756 return Builtin::BI__builtin_labs; 4757 case Builtin::BI__builtin_labs: 4758 return Builtin::BI__builtin_llabs; 4759 case Builtin::BI__builtin_llabs: 4760 return 0; 4761 4762 case Builtin::BI__builtin_fabsf: 4763 return Builtin::BI__builtin_fabs; 4764 case Builtin::BI__builtin_fabs: 4765 return Builtin::BI__builtin_fabsl; 4766 case Builtin::BI__builtin_fabsl: 4767 return 0; 4768 4769 case Builtin::BI__builtin_cabsf: 4770 return Builtin::BI__builtin_cabs; 4771 case Builtin::BI__builtin_cabs: 4772 return Builtin::BI__builtin_cabsl; 4773 case Builtin::BI__builtin_cabsl: 4774 return 0; 4775 4776 case Builtin::BIabs: 4777 return Builtin::BIlabs; 4778 case Builtin::BIlabs: 4779 return Builtin::BIllabs; 4780 case Builtin::BIllabs: 4781 return 0; 4782 4783 case Builtin::BIfabsf: 4784 return Builtin::BIfabs; 4785 case Builtin::BIfabs: 4786 return Builtin::BIfabsl; 4787 case Builtin::BIfabsl: 4788 return 0; 4789 4790 case Builtin::BIcabsf: 4791 return Builtin::BIcabs; 4792 case Builtin::BIcabs: 4793 return Builtin::BIcabsl; 4794 case Builtin::BIcabsl: 4795 return 0; 4796 } 4797 } 4798 4799 // Returns the argument type of the absolute value function. 4800 static QualType getAbsoluteValueArgumentType(ASTContext &Context, 4801 unsigned AbsType) { 4802 if (AbsType == 0) 4803 return QualType(); 4804 4805 ASTContext::GetBuiltinTypeError Error = ASTContext::GE_None; 4806 QualType BuiltinType = Context.GetBuiltinType(AbsType, Error); 4807 if (Error != ASTContext::GE_None) 4808 return QualType(); 4809 4810 const FunctionProtoType *FT = BuiltinType->getAs<FunctionProtoType>(); 4811 if (!FT) 4812 return QualType(); 4813 4814 if (FT->getNumParams() != 1) 4815 return QualType(); 4816 4817 return FT->getParamType(0); 4818 } 4819 4820 // Returns the best absolute value function, or zero, based on type and 4821 // current absolute value function. 4822 static unsigned getBestAbsFunction(ASTContext &Context, QualType ArgType, 4823 unsigned AbsFunctionKind) { 4824 unsigned BestKind = 0; 4825 uint64_t ArgSize = Context.getTypeSize(ArgType); 4826 for (unsigned Kind = AbsFunctionKind; Kind != 0; 4827 Kind = getLargerAbsoluteValueFunction(Kind)) { 4828 QualType ParamType = getAbsoluteValueArgumentType(Context, Kind); 4829 if (Context.getTypeSize(ParamType) >= ArgSize) { 4830 if (BestKind == 0) 4831 BestKind = Kind; 4832 else if (Context.hasSameType(ParamType, ArgType)) { 4833 BestKind = Kind; 4834 break; 4835 } 4836 } 4837 } 4838 return BestKind; 4839 } 4840 4841 enum AbsoluteValueKind { 4842 AVK_Integer, 4843 AVK_Floating, 4844 AVK_Complex 4845 }; 4846 4847 static AbsoluteValueKind getAbsoluteValueKind(QualType T) { 4848 if (T->isIntegralOrEnumerationType()) 4849 return AVK_Integer; 4850 if (T->isRealFloatingType()) 4851 return AVK_Floating; 4852 if (T->isAnyComplexType()) 4853 return AVK_Complex; 4854 4855 llvm_unreachable("Type not integer, floating, or complex"); 4856 } 4857 4858 // Changes the absolute value function to a different type. Preserves whether 4859 // the function is a builtin. 4860 static unsigned changeAbsFunction(unsigned AbsKind, 4861 AbsoluteValueKind ValueKind) { 4862 switch (ValueKind) { 4863 case AVK_Integer: 4864 switch (AbsKind) { 4865 default: 4866 return 0; 4867 case Builtin::BI__builtin_fabsf: 4868 case Builtin::BI__builtin_fabs: 4869 case Builtin::BI__builtin_fabsl: 4870 case Builtin::BI__builtin_cabsf: 4871 case Builtin::BI__builtin_cabs: 4872 case Builtin::BI__builtin_cabsl: 4873 return Builtin::BI__builtin_abs; 4874 case Builtin::BIfabsf: 4875 case Builtin::BIfabs: 4876 case Builtin::BIfabsl: 4877 case Builtin::BIcabsf: 4878 case Builtin::BIcabs: 4879 case Builtin::BIcabsl: 4880 return Builtin::BIabs; 4881 } 4882 case AVK_Floating: 4883 switch (AbsKind) { 4884 default: 4885 return 0; 4886 case Builtin::BI__builtin_abs: 4887 case Builtin::BI__builtin_labs: 4888 case Builtin::BI__builtin_llabs: 4889 case Builtin::BI__builtin_cabsf: 4890 case Builtin::BI__builtin_cabs: 4891 case Builtin::BI__builtin_cabsl: 4892 return Builtin::BI__builtin_fabsf; 4893 case Builtin::BIabs: 4894 case Builtin::BIlabs: 4895 case Builtin::BIllabs: 4896 case Builtin::BIcabsf: 4897 case Builtin::BIcabs: 4898 case Builtin::BIcabsl: 4899 return Builtin::BIfabsf; 4900 } 4901 case AVK_Complex: 4902 switch (AbsKind) { 4903 default: 4904 return 0; 4905 case Builtin::BI__builtin_abs: 4906 case Builtin::BI__builtin_labs: 4907 case Builtin::BI__builtin_llabs: 4908 case Builtin::BI__builtin_fabsf: 4909 case Builtin::BI__builtin_fabs: 4910 case Builtin::BI__builtin_fabsl: 4911 return Builtin::BI__builtin_cabsf; 4912 case Builtin::BIabs: 4913 case Builtin::BIlabs: 4914 case Builtin::BIllabs: 4915 case Builtin::BIfabsf: 4916 case Builtin::BIfabs: 4917 case Builtin::BIfabsl: 4918 return Builtin::BIcabsf; 4919 } 4920 } 4921 llvm_unreachable("Unable to convert function"); 4922 } 4923 4924 static unsigned getAbsoluteValueFunctionKind(const FunctionDecl *FDecl) { 4925 const IdentifierInfo *FnInfo = FDecl->getIdentifier(); 4926 if (!FnInfo) 4927 return 0; 4928 4929 switch (FDecl->getBuiltinID()) { 4930 default: 4931 return 0; 4932 case Builtin::BI__builtin_abs: 4933 case Builtin::BI__builtin_fabs: 4934 case Builtin::BI__builtin_fabsf: 4935 case Builtin::BI__builtin_fabsl: 4936 case Builtin::BI__builtin_labs: 4937 case Builtin::BI__builtin_llabs: 4938 case Builtin::BI__builtin_cabs: 4939 case Builtin::BI__builtin_cabsf: 4940 case Builtin::BI__builtin_cabsl: 4941 case Builtin::BIabs: 4942 case Builtin::BIlabs: 4943 case Builtin::BIllabs: 4944 case Builtin::BIfabs: 4945 case Builtin::BIfabsf: 4946 case Builtin::BIfabsl: 4947 case Builtin::BIcabs: 4948 case Builtin::BIcabsf: 4949 case Builtin::BIcabsl: 4950 return FDecl->getBuiltinID(); 4951 } 4952 llvm_unreachable("Unknown Builtin type"); 4953 } 4954 4955 // If the replacement is valid, emit a note with replacement function. 4956 // Additionally, suggest including the proper header if not already included. 4957 static void emitReplacement(Sema &S, SourceLocation Loc, SourceRange Range, 4958 unsigned AbsKind, QualType ArgType) { 4959 bool EmitHeaderHint = true; 4960 const char *HeaderName = nullptr; 4961 const char *FunctionName = nullptr; 4962 if (S.getLangOpts().CPlusPlus && !ArgType->isAnyComplexType()) { 4963 FunctionName = "std::abs"; 4964 if (ArgType->isIntegralOrEnumerationType()) { 4965 HeaderName = "cstdlib"; 4966 } else if (ArgType->isRealFloatingType()) { 4967 HeaderName = "cmath"; 4968 } else { 4969 llvm_unreachable("Invalid Type"); 4970 } 4971 4972 // Lookup all std::abs 4973 if (NamespaceDecl *Std = S.getStdNamespace()) { 4974 LookupResult R(S, &S.Context.Idents.get("abs"), Loc, Sema::LookupAnyName); 4975 R.suppressDiagnostics(); 4976 S.LookupQualifiedName(R, Std); 4977 4978 for (const auto *I : R) { 4979 const FunctionDecl *FDecl = nullptr; 4980 if (const UsingShadowDecl *UsingD = dyn_cast<UsingShadowDecl>(I)) { 4981 FDecl = dyn_cast<FunctionDecl>(UsingD->getTargetDecl()); 4982 } else { 4983 FDecl = dyn_cast<FunctionDecl>(I); 4984 } 4985 if (!FDecl) 4986 continue; 4987 4988 // Found std::abs(), check that they are the right ones. 4989 if (FDecl->getNumParams() != 1) 4990 continue; 4991 4992 // Check that the parameter type can handle the argument. 4993 QualType ParamType = FDecl->getParamDecl(0)->getType(); 4994 if (getAbsoluteValueKind(ArgType) == getAbsoluteValueKind(ParamType) && 4995 S.Context.getTypeSize(ArgType) <= 4996 S.Context.getTypeSize(ParamType)) { 4997 // Found a function, don't need the header hint. 4998 EmitHeaderHint = false; 4999 break; 5000 } 5001 } 5002 } 5003 } else { 5004 FunctionName = S.Context.BuiltinInfo.getName(AbsKind); 5005 HeaderName = S.Context.BuiltinInfo.getHeaderName(AbsKind); 5006 5007 if (HeaderName) { 5008 DeclarationName DN(&S.Context.Idents.get(FunctionName)); 5009 LookupResult R(S, DN, Loc, Sema::LookupAnyName); 5010 R.suppressDiagnostics(); 5011 S.LookupName(R, S.getCurScope()); 5012 5013 if (R.isSingleResult()) { 5014 FunctionDecl *FD = dyn_cast<FunctionDecl>(R.getFoundDecl()); 5015 if (FD && FD->getBuiltinID() == AbsKind) { 5016 EmitHeaderHint = false; 5017 } else { 5018 return; 5019 } 5020 } else if (!R.empty()) { 5021 return; 5022 } 5023 } 5024 } 5025 5026 S.Diag(Loc, diag::note_replace_abs_function) 5027 << FunctionName << FixItHint::CreateReplacement(Range, FunctionName); 5028 5029 if (!HeaderName) 5030 return; 5031 5032 if (!EmitHeaderHint) 5033 return; 5034 5035 S.Diag(Loc, diag::note_include_header_or_declare) << HeaderName 5036 << FunctionName; 5037 } 5038 5039 static bool IsFunctionStdAbs(const FunctionDecl *FDecl) { 5040 if (!FDecl) 5041 return false; 5042 5043 if (!FDecl->getIdentifier() || !FDecl->getIdentifier()->isStr("abs")) 5044 return false; 5045 5046 const NamespaceDecl *ND = dyn_cast<NamespaceDecl>(FDecl->getDeclContext()); 5047 5048 while (ND && ND->isInlineNamespace()) { 5049 ND = dyn_cast<NamespaceDecl>(ND->getDeclContext()); 5050 } 5051 5052 if (!ND || !ND->getIdentifier() || !ND->getIdentifier()->isStr("std")) 5053 return false; 5054 5055 if (!isa<TranslationUnitDecl>(ND->getDeclContext())) 5056 return false; 5057 5058 return true; 5059 } 5060 5061 // Warn when using the wrong abs() function. 5062 void Sema::CheckAbsoluteValueFunction(const CallExpr *Call, 5063 const FunctionDecl *FDecl, 5064 IdentifierInfo *FnInfo) { 5065 if (Call->getNumArgs() != 1) 5066 return; 5067 5068 unsigned AbsKind = getAbsoluteValueFunctionKind(FDecl); 5069 bool IsStdAbs = IsFunctionStdAbs(FDecl); 5070 if (AbsKind == 0 && !IsStdAbs) 5071 return; 5072 5073 QualType ArgType = Call->getArg(0)->IgnoreParenImpCasts()->getType(); 5074 QualType ParamType = Call->getArg(0)->getType(); 5075 5076 // Unsigned types cannot be negative. Suggest removing the absolute value 5077 // function call. 5078 if (ArgType->isUnsignedIntegerType()) { 5079 const char *FunctionName = 5080 IsStdAbs ? "std::abs" : Context.BuiltinInfo.getName(AbsKind); 5081 Diag(Call->getExprLoc(), diag::warn_unsigned_abs) << ArgType << ParamType; 5082 Diag(Call->getExprLoc(), diag::note_remove_abs) 5083 << FunctionName 5084 << FixItHint::CreateRemoval(Call->getCallee()->getSourceRange()); 5085 return; 5086 } 5087 5088 // std::abs has overloads which prevent most of the absolute value problems 5089 // from occurring. 5090 if (IsStdAbs) 5091 return; 5092 5093 AbsoluteValueKind ArgValueKind = getAbsoluteValueKind(ArgType); 5094 AbsoluteValueKind ParamValueKind = getAbsoluteValueKind(ParamType); 5095 5096 // The argument and parameter are the same kind. Check if they are the right 5097 // size. 5098 if (ArgValueKind == ParamValueKind) { 5099 if (Context.getTypeSize(ArgType) <= Context.getTypeSize(ParamType)) 5100 return; 5101 5102 unsigned NewAbsKind = getBestAbsFunction(Context, ArgType, AbsKind); 5103 Diag(Call->getExprLoc(), diag::warn_abs_too_small) 5104 << FDecl << ArgType << ParamType; 5105 5106 if (NewAbsKind == 0) 5107 return; 5108 5109 emitReplacement(*this, Call->getExprLoc(), 5110 Call->getCallee()->getSourceRange(), NewAbsKind, ArgType); 5111 return; 5112 } 5113 5114 // ArgValueKind != ParamValueKind 5115 // The wrong type of absolute value function was used. Attempt to find the 5116 // proper one. 5117 unsigned NewAbsKind = changeAbsFunction(AbsKind, ArgValueKind); 5118 NewAbsKind = getBestAbsFunction(Context, ArgType, NewAbsKind); 5119 if (NewAbsKind == 0) 5120 return; 5121 5122 Diag(Call->getExprLoc(), diag::warn_wrong_absolute_value_type) 5123 << FDecl << ParamValueKind << ArgValueKind; 5124 5125 emitReplacement(*this, Call->getExprLoc(), 5126 Call->getCallee()->getSourceRange(), NewAbsKind, ArgType); 5127 return; 5128 } 5129 5130 //===--- CHECK: Standard memory functions ---------------------------------===// 5131 5132 /// \brief Takes the expression passed to the size_t parameter of functions 5133 /// such as memcmp, strncat, etc and warns if it's a comparison. 5134 /// 5135 /// This is to catch typos like `if (memcmp(&a, &b, sizeof(a) > 0))`. 5136 static bool CheckMemorySizeofForComparison(Sema &S, const Expr *E, 5137 IdentifierInfo *FnName, 5138 SourceLocation FnLoc, 5139 SourceLocation RParenLoc) { 5140 const BinaryOperator *Size = dyn_cast<BinaryOperator>(E); 5141 if (!Size) 5142 return false; 5143 5144 // if E is binop and op is >, <, >=, <=, ==, &&, ||: 5145 if (!Size->isComparisonOp() && !Size->isEqualityOp() && !Size->isLogicalOp()) 5146 return false; 5147 5148 SourceRange SizeRange = Size->getSourceRange(); 5149 S.Diag(Size->getOperatorLoc(), diag::warn_memsize_comparison) 5150 << SizeRange << FnName; 5151 S.Diag(FnLoc, diag::note_memsize_comparison_paren) 5152 << FnName << FixItHint::CreateInsertion( 5153 S.getLocForEndOfToken(Size->getLHS()->getLocEnd()), ")") 5154 << FixItHint::CreateRemoval(RParenLoc); 5155 S.Diag(SizeRange.getBegin(), diag::note_memsize_comparison_cast_silence) 5156 << FixItHint::CreateInsertion(SizeRange.getBegin(), "(size_t)(") 5157 << FixItHint::CreateInsertion(S.getLocForEndOfToken(SizeRange.getEnd()), 5158 ")"); 5159 5160 return true; 5161 } 5162 5163 /// \brief Determine whether the given type is or contains a dynamic class type 5164 /// (e.g., whether it has a vtable). 5165 static const CXXRecordDecl *getContainedDynamicClass(QualType T, 5166 bool &IsContained) { 5167 // Look through array types while ignoring qualifiers. 5168 const Type *Ty = T->getBaseElementTypeUnsafe(); 5169 IsContained = false; 5170 5171 const CXXRecordDecl *RD = Ty->getAsCXXRecordDecl(); 5172 RD = RD ? RD->getDefinition() : nullptr; 5173 if (!RD) 5174 return nullptr; 5175 5176 if (RD->isDynamicClass()) 5177 return RD; 5178 5179 // Check all the fields. If any bases were dynamic, the class is dynamic. 5180 // It's impossible for a class to transitively contain itself by value, so 5181 // infinite recursion is impossible. 5182 for (auto *FD : RD->fields()) { 5183 bool SubContained; 5184 if (const CXXRecordDecl *ContainedRD = 5185 getContainedDynamicClass(FD->getType(), SubContained)) { 5186 IsContained = true; 5187 return ContainedRD; 5188 } 5189 } 5190 5191 return nullptr; 5192 } 5193 5194 /// \brief If E is a sizeof expression, returns its argument expression, 5195 /// otherwise returns NULL. 5196 static const Expr *getSizeOfExprArg(const Expr *E) { 5197 if (const UnaryExprOrTypeTraitExpr *SizeOf = 5198 dyn_cast<UnaryExprOrTypeTraitExpr>(E)) 5199 if (SizeOf->getKind() == clang::UETT_SizeOf && !SizeOf->isArgumentType()) 5200 return SizeOf->getArgumentExpr()->IgnoreParenImpCasts(); 5201 5202 return nullptr; 5203 } 5204 5205 /// \brief If E is a sizeof expression, returns its argument type. 5206 static QualType getSizeOfArgType(const Expr *E) { 5207 if (const UnaryExprOrTypeTraitExpr *SizeOf = 5208 dyn_cast<UnaryExprOrTypeTraitExpr>(E)) 5209 if (SizeOf->getKind() == clang::UETT_SizeOf) 5210 return SizeOf->getTypeOfArgument(); 5211 5212 return QualType(); 5213 } 5214 5215 /// \brief Check for dangerous or invalid arguments to memset(). 5216 /// 5217 /// This issues warnings on known problematic, dangerous or unspecified 5218 /// arguments to the standard 'memset', 'memcpy', 'memmove', and 'memcmp' 5219 /// function calls. 5220 /// 5221 /// \param Call The call expression to diagnose. 5222 void Sema::CheckMemaccessArguments(const CallExpr *Call, 5223 unsigned BId, 5224 IdentifierInfo *FnName) { 5225 assert(BId != 0); 5226 5227 // It is possible to have a non-standard definition of memset. Validate 5228 // we have enough arguments, and if not, abort further checking. 5229 unsigned ExpectedNumArgs = (BId == Builtin::BIstrndup ? 2 : 3); 5230 if (Call->getNumArgs() < ExpectedNumArgs) 5231 return; 5232 5233 unsigned LastArg = (BId == Builtin::BImemset || 5234 BId == Builtin::BIstrndup ? 1 : 2); 5235 unsigned LenArg = (BId == Builtin::BIstrndup ? 1 : 2); 5236 const Expr *LenExpr = Call->getArg(LenArg)->IgnoreParenImpCasts(); 5237 5238 if (CheckMemorySizeofForComparison(*this, LenExpr, FnName, 5239 Call->getLocStart(), Call->getRParenLoc())) 5240 return; 5241 5242 // We have special checking when the length is a sizeof expression. 5243 QualType SizeOfArgTy = getSizeOfArgType(LenExpr); 5244 const Expr *SizeOfArg = getSizeOfExprArg(LenExpr); 5245 llvm::FoldingSetNodeID SizeOfArgID; 5246 5247 for (unsigned ArgIdx = 0; ArgIdx != LastArg; ++ArgIdx) { 5248 const Expr *Dest = Call->getArg(ArgIdx)->IgnoreParenImpCasts(); 5249 SourceRange ArgRange = Call->getArg(ArgIdx)->getSourceRange(); 5250 5251 QualType DestTy = Dest->getType(); 5252 QualType PointeeTy; 5253 if (const PointerType *DestPtrTy = DestTy->getAs<PointerType>()) { 5254 PointeeTy = DestPtrTy->getPointeeType(); 5255 5256 // Never warn about void type pointers. This can be used to suppress 5257 // false positives. 5258 if (PointeeTy->isVoidType()) 5259 continue; 5260 5261 // Catch "memset(p, 0, sizeof(p))" -- needs to be sizeof(*p). Do this by 5262 // actually comparing the expressions for equality. Because computing the 5263 // expression IDs can be expensive, we only do this if the diagnostic is 5264 // enabled. 5265 if (SizeOfArg && 5266 !Diags.isIgnored(diag::warn_sizeof_pointer_expr_memaccess, 5267 SizeOfArg->getExprLoc())) { 5268 // We only compute IDs for expressions if the warning is enabled, and 5269 // cache the sizeof arg's ID. 5270 if (SizeOfArgID == llvm::FoldingSetNodeID()) 5271 SizeOfArg->Profile(SizeOfArgID, Context, true); 5272 llvm::FoldingSetNodeID DestID; 5273 Dest->Profile(DestID, Context, true); 5274 if (DestID == SizeOfArgID) { 5275 // TODO: For strncpy() and friends, this could suggest sizeof(dst) 5276 // over sizeof(src) as well. 5277 unsigned ActionIdx = 0; // Default is to suggest dereferencing. 5278 StringRef ReadableName = FnName->getName(); 5279 5280 if (const UnaryOperator *UnaryOp = dyn_cast<UnaryOperator>(Dest)) 5281 if (UnaryOp->getOpcode() == UO_AddrOf) 5282 ActionIdx = 1; // If its an address-of operator, just remove it. 5283 if (!PointeeTy->isIncompleteType() && 5284 (Context.getTypeSize(PointeeTy) == Context.getCharWidth())) 5285 ActionIdx = 2; // If the pointee's size is sizeof(char), 5286 // suggest an explicit length. 5287 5288 // If the function is defined as a builtin macro, do not show macro 5289 // expansion. 5290 SourceLocation SL = SizeOfArg->getExprLoc(); 5291 SourceRange DSR = Dest->getSourceRange(); 5292 SourceRange SSR = SizeOfArg->getSourceRange(); 5293 SourceManager &SM = getSourceManager(); 5294 5295 if (SM.isMacroArgExpansion(SL)) { 5296 ReadableName = Lexer::getImmediateMacroName(SL, SM, LangOpts); 5297 SL = SM.getSpellingLoc(SL); 5298 DSR = SourceRange(SM.getSpellingLoc(DSR.getBegin()), 5299 SM.getSpellingLoc(DSR.getEnd())); 5300 SSR = SourceRange(SM.getSpellingLoc(SSR.getBegin()), 5301 SM.getSpellingLoc(SSR.getEnd())); 5302 } 5303 5304 DiagRuntimeBehavior(SL, SizeOfArg, 5305 PDiag(diag::warn_sizeof_pointer_expr_memaccess) 5306 << ReadableName 5307 << PointeeTy 5308 << DestTy 5309 << DSR 5310 << SSR); 5311 DiagRuntimeBehavior(SL, SizeOfArg, 5312 PDiag(diag::warn_sizeof_pointer_expr_memaccess_note) 5313 << ActionIdx 5314 << SSR); 5315 5316 break; 5317 } 5318 } 5319 5320 // Also check for cases where the sizeof argument is the exact same 5321 // type as the memory argument, and where it points to a user-defined 5322 // record type. 5323 if (SizeOfArgTy != QualType()) { 5324 if (PointeeTy->isRecordType() && 5325 Context.typesAreCompatible(SizeOfArgTy, DestTy)) { 5326 DiagRuntimeBehavior(LenExpr->getExprLoc(), Dest, 5327 PDiag(diag::warn_sizeof_pointer_type_memaccess) 5328 << FnName << SizeOfArgTy << ArgIdx 5329 << PointeeTy << Dest->getSourceRange() 5330 << LenExpr->getSourceRange()); 5331 break; 5332 } 5333 } 5334 } else if (DestTy->isArrayType()) { 5335 PointeeTy = DestTy; 5336 } 5337 5338 if (PointeeTy == QualType()) 5339 continue; 5340 5341 // Always complain about dynamic classes. 5342 bool IsContained; 5343 if (const CXXRecordDecl *ContainedRD = 5344 getContainedDynamicClass(PointeeTy, IsContained)) { 5345 5346 unsigned OperationType = 0; 5347 // "overwritten" if we're warning about the destination for any call 5348 // but memcmp; otherwise a verb appropriate to the call. 5349 if (ArgIdx != 0 || BId == Builtin::BImemcmp) { 5350 if (BId == Builtin::BImemcpy) 5351 OperationType = 1; 5352 else if(BId == Builtin::BImemmove) 5353 OperationType = 2; 5354 else if (BId == Builtin::BImemcmp) 5355 OperationType = 3; 5356 } 5357 5358 DiagRuntimeBehavior( 5359 Dest->getExprLoc(), Dest, 5360 PDiag(diag::warn_dyn_class_memaccess) 5361 << (BId == Builtin::BImemcmp ? ArgIdx + 2 : ArgIdx) 5362 << FnName << IsContained << ContainedRD << OperationType 5363 << Call->getCallee()->getSourceRange()); 5364 } else if (PointeeTy.hasNonTrivialObjCLifetime() && 5365 BId != Builtin::BImemset) 5366 DiagRuntimeBehavior( 5367 Dest->getExprLoc(), Dest, 5368 PDiag(diag::warn_arc_object_memaccess) 5369 << ArgIdx << FnName << PointeeTy 5370 << Call->getCallee()->getSourceRange()); 5371 else 5372 continue; 5373 5374 DiagRuntimeBehavior( 5375 Dest->getExprLoc(), Dest, 5376 PDiag(diag::note_bad_memaccess_silence) 5377 << FixItHint::CreateInsertion(ArgRange.getBegin(), "(void*)")); 5378 break; 5379 } 5380 5381 } 5382 5383 // A little helper routine: ignore addition and subtraction of integer literals. 5384 // This intentionally does not ignore all integer constant expressions because 5385 // we don't want to remove sizeof(). 5386 static const Expr *ignoreLiteralAdditions(const Expr *Ex, ASTContext &Ctx) { 5387 Ex = Ex->IgnoreParenCasts(); 5388 5389 for (;;) { 5390 const BinaryOperator * BO = dyn_cast<BinaryOperator>(Ex); 5391 if (!BO || !BO->isAdditiveOp()) 5392 break; 5393 5394 const Expr *RHS = BO->getRHS()->IgnoreParenCasts(); 5395 const Expr *LHS = BO->getLHS()->IgnoreParenCasts(); 5396 5397 if (isa<IntegerLiteral>(RHS)) 5398 Ex = LHS; 5399 else if (isa<IntegerLiteral>(LHS)) 5400 Ex = RHS; 5401 else 5402 break; 5403 } 5404 5405 return Ex; 5406 } 5407 5408 static bool isConstantSizeArrayWithMoreThanOneElement(QualType Ty, 5409 ASTContext &Context) { 5410 // Only handle constant-sized or VLAs, but not flexible members. 5411 if (const ConstantArrayType *CAT = Context.getAsConstantArrayType(Ty)) { 5412 // Only issue the FIXIT for arrays of size > 1. 5413 if (CAT->getSize().getSExtValue() <= 1) 5414 return false; 5415 } else if (!Ty->isVariableArrayType()) { 5416 return false; 5417 } 5418 return true; 5419 } 5420 5421 // Warn if the user has made the 'size' argument to strlcpy or strlcat 5422 // be the size of the source, instead of the destination. 5423 void Sema::CheckStrlcpycatArguments(const CallExpr *Call, 5424 IdentifierInfo *FnName) { 5425 5426 // Don't crash if the user has the wrong number of arguments 5427 unsigned NumArgs = Call->getNumArgs(); 5428 if ((NumArgs != 3) && (NumArgs != 4)) 5429 return; 5430 5431 const Expr *SrcArg = ignoreLiteralAdditions(Call->getArg(1), Context); 5432 const Expr *SizeArg = ignoreLiteralAdditions(Call->getArg(2), Context); 5433 const Expr *CompareWithSrc = nullptr; 5434 5435 if (CheckMemorySizeofForComparison(*this, SizeArg, FnName, 5436 Call->getLocStart(), Call->getRParenLoc())) 5437 return; 5438 5439 // Look for 'strlcpy(dst, x, sizeof(x))' 5440 if (const Expr *Ex = getSizeOfExprArg(SizeArg)) 5441 CompareWithSrc = Ex; 5442 else { 5443 // Look for 'strlcpy(dst, x, strlen(x))' 5444 if (const CallExpr *SizeCall = dyn_cast<CallExpr>(SizeArg)) { 5445 if (SizeCall->getBuiltinCallee() == Builtin::BIstrlen && 5446 SizeCall->getNumArgs() == 1) 5447 CompareWithSrc = ignoreLiteralAdditions(SizeCall->getArg(0), Context); 5448 } 5449 } 5450 5451 if (!CompareWithSrc) 5452 return; 5453 5454 // Determine if the argument to sizeof/strlen is equal to the source 5455 // argument. In principle there's all kinds of things you could do 5456 // here, for instance creating an == expression and evaluating it with 5457 // EvaluateAsBooleanCondition, but this uses a more direct technique: 5458 const DeclRefExpr *SrcArgDRE = dyn_cast<DeclRefExpr>(SrcArg); 5459 if (!SrcArgDRE) 5460 return; 5461 5462 const DeclRefExpr *CompareWithSrcDRE = dyn_cast<DeclRefExpr>(CompareWithSrc); 5463 if (!CompareWithSrcDRE || 5464 SrcArgDRE->getDecl() != CompareWithSrcDRE->getDecl()) 5465 return; 5466 5467 const Expr *OriginalSizeArg = Call->getArg(2); 5468 Diag(CompareWithSrcDRE->getLocStart(), diag::warn_strlcpycat_wrong_size) 5469 << OriginalSizeArg->getSourceRange() << FnName; 5470 5471 // Output a FIXIT hint if the destination is an array (rather than a 5472 // pointer to an array). This could be enhanced to handle some 5473 // pointers if we know the actual size, like if DstArg is 'array+2' 5474 // we could say 'sizeof(array)-2'. 5475 const Expr *DstArg = Call->getArg(0)->IgnoreParenImpCasts(); 5476 if (!isConstantSizeArrayWithMoreThanOneElement(DstArg->getType(), Context)) 5477 return; 5478 5479 SmallString<128> sizeString; 5480 llvm::raw_svector_ostream OS(sizeString); 5481 OS << "sizeof("; 5482 DstArg->printPretty(OS, nullptr, getPrintingPolicy()); 5483 OS << ")"; 5484 5485 Diag(OriginalSizeArg->getLocStart(), diag::note_strlcpycat_wrong_size) 5486 << FixItHint::CreateReplacement(OriginalSizeArg->getSourceRange(), 5487 OS.str()); 5488 } 5489 5490 /// Check if two expressions refer to the same declaration. 5491 static bool referToTheSameDecl(const Expr *E1, const Expr *E2) { 5492 if (const DeclRefExpr *D1 = dyn_cast_or_null<DeclRefExpr>(E1)) 5493 if (const DeclRefExpr *D2 = dyn_cast_or_null<DeclRefExpr>(E2)) 5494 return D1->getDecl() == D2->getDecl(); 5495 return false; 5496 } 5497 5498 static const Expr *getStrlenExprArg(const Expr *E) { 5499 if (const CallExpr *CE = dyn_cast<CallExpr>(E)) { 5500 const FunctionDecl *FD = CE->getDirectCallee(); 5501 if (!FD || FD->getMemoryFunctionKind() != Builtin::BIstrlen) 5502 return nullptr; 5503 return CE->getArg(0)->IgnoreParenCasts(); 5504 } 5505 return nullptr; 5506 } 5507 5508 // Warn on anti-patterns as the 'size' argument to strncat. 5509 // The correct size argument should look like following: 5510 // strncat(dst, src, sizeof(dst) - strlen(dest) - 1); 5511 void Sema::CheckStrncatArguments(const CallExpr *CE, 5512 IdentifierInfo *FnName) { 5513 // Don't crash if the user has the wrong number of arguments. 5514 if (CE->getNumArgs() < 3) 5515 return; 5516 const Expr *DstArg = CE->getArg(0)->IgnoreParenCasts(); 5517 const Expr *SrcArg = CE->getArg(1)->IgnoreParenCasts(); 5518 const Expr *LenArg = CE->getArg(2)->IgnoreParenCasts(); 5519 5520 if (CheckMemorySizeofForComparison(*this, LenArg, FnName, CE->getLocStart(), 5521 CE->getRParenLoc())) 5522 return; 5523 5524 // Identify common expressions, which are wrongly used as the size argument 5525 // to strncat and may lead to buffer overflows. 5526 unsigned PatternType = 0; 5527 if (const Expr *SizeOfArg = getSizeOfExprArg(LenArg)) { 5528 // - sizeof(dst) 5529 if (referToTheSameDecl(SizeOfArg, DstArg)) 5530 PatternType = 1; 5531 // - sizeof(src) 5532 else if (referToTheSameDecl(SizeOfArg, SrcArg)) 5533 PatternType = 2; 5534 } else if (const BinaryOperator *BE = dyn_cast<BinaryOperator>(LenArg)) { 5535 if (BE->getOpcode() == BO_Sub) { 5536 const Expr *L = BE->getLHS()->IgnoreParenCasts(); 5537 const Expr *R = BE->getRHS()->IgnoreParenCasts(); 5538 // - sizeof(dst) - strlen(dst) 5539 if (referToTheSameDecl(DstArg, getSizeOfExprArg(L)) && 5540 referToTheSameDecl(DstArg, getStrlenExprArg(R))) 5541 PatternType = 1; 5542 // - sizeof(src) - (anything) 5543 else if (referToTheSameDecl(SrcArg, getSizeOfExprArg(L))) 5544 PatternType = 2; 5545 } 5546 } 5547 5548 if (PatternType == 0) 5549 return; 5550 5551 // Generate the diagnostic. 5552 SourceLocation SL = LenArg->getLocStart(); 5553 SourceRange SR = LenArg->getSourceRange(); 5554 SourceManager &SM = getSourceManager(); 5555 5556 // If the function is defined as a builtin macro, do not show macro expansion. 5557 if (SM.isMacroArgExpansion(SL)) { 5558 SL = SM.getSpellingLoc(SL); 5559 SR = SourceRange(SM.getSpellingLoc(SR.getBegin()), 5560 SM.getSpellingLoc(SR.getEnd())); 5561 } 5562 5563 // Check if the destination is an array (rather than a pointer to an array). 5564 QualType DstTy = DstArg->getType(); 5565 bool isKnownSizeArray = isConstantSizeArrayWithMoreThanOneElement(DstTy, 5566 Context); 5567 if (!isKnownSizeArray) { 5568 if (PatternType == 1) 5569 Diag(SL, diag::warn_strncat_wrong_size) << SR; 5570 else 5571 Diag(SL, diag::warn_strncat_src_size) << SR; 5572 return; 5573 } 5574 5575 if (PatternType == 1) 5576 Diag(SL, diag::warn_strncat_large_size) << SR; 5577 else 5578 Diag(SL, diag::warn_strncat_src_size) << SR; 5579 5580 SmallString<128> sizeString; 5581 llvm::raw_svector_ostream OS(sizeString); 5582 OS << "sizeof("; 5583 DstArg->printPretty(OS, nullptr, getPrintingPolicy()); 5584 OS << ") - "; 5585 OS << "strlen("; 5586 DstArg->printPretty(OS, nullptr, getPrintingPolicy()); 5587 OS << ") - 1"; 5588 5589 Diag(SL, diag::note_strncat_wrong_size) 5590 << FixItHint::CreateReplacement(SR, OS.str()); 5591 } 5592 5593 //===--- CHECK: Return Address of Stack Variable --------------------------===// 5594 5595 static Expr *EvalVal(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars, 5596 Decl *ParentDecl); 5597 static Expr *EvalAddr(Expr* E, SmallVectorImpl<DeclRefExpr *> &refVars, 5598 Decl *ParentDecl); 5599 5600 /// CheckReturnStackAddr - Check if a return statement returns the address 5601 /// of a stack variable. 5602 static void 5603 CheckReturnStackAddr(Sema &S, Expr *RetValExp, QualType lhsType, 5604 SourceLocation ReturnLoc) { 5605 5606 Expr *stackE = nullptr; 5607 SmallVector<DeclRefExpr *, 8> refVars; 5608 5609 // Perform checking for returned stack addresses, local blocks, 5610 // label addresses or references to temporaries. 5611 if (lhsType->isPointerType() || 5612 (!S.getLangOpts().ObjCAutoRefCount && lhsType->isBlockPointerType())) { 5613 stackE = EvalAddr(RetValExp, refVars, /*ParentDecl=*/nullptr); 5614 } else if (lhsType->isReferenceType()) { 5615 stackE = EvalVal(RetValExp, refVars, /*ParentDecl=*/nullptr); 5616 } 5617 5618 if (!stackE) 5619 return; // Nothing suspicious was found. 5620 5621 SourceLocation diagLoc; 5622 SourceRange diagRange; 5623 if (refVars.empty()) { 5624 diagLoc = stackE->getLocStart(); 5625 diagRange = stackE->getSourceRange(); 5626 } else { 5627 // We followed through a reference variable. 'stackE' contains the 5628 // problematic expression but we will warn at the return statement pointing 5629 // at the reference variable. We will later display the "trail" of 5630 // reference variables using notes. 5631 diagLoc = refVars[0]->getLocStart(); 5632 diagRange = refVars[0]->getSourceRange(); 5633 } 5634 5635 if (DeclRefExpr *DR = dyn_cast<DeclRefExpr>(stackE)) { //address of local var. 5636 S.Diag(diagLoc, lhsType->isReferenceType() ? diag::warn_ret_stack_ref 5637 : diag::warn_ret_stack_addr) 5638 << DR->getDecl()->getDeclName() << diagRange; 5639 } else if (isa<BlockExpr>(stackE)) { // local block. 5640 S.Diag(diagLoc, diag::err_ret_local_block) << diagRange; 5641 } else if (isa<AddrLabelExpr>(stackE)) { // address of label. 5642 S.Diag(diagLoc, diag::warn_ret_addr_label) << diagRange; 5643 } else { // local temporary. 5644 S.Diag(diagLoc, lhsType->isReferenceType() ? diag::warn_ret_local_temp_ref 5645 : diag::warn_ret_local_temp_addr) 5646 << diagRange; 5647 } 5648 5649 // Display the "trail" of reference variables that we followed until we 5650 // found the problematic expression using notes. 5651 for (unsigned i = 0, e = refVars.size(); i != e; ++i) { 5652 VarDecl *VD = cast<VarDecl>(refVars[i]->getDecl()); 5653 // If this var binds to another reference var, show the range of the next 5654 // var, otherwise the var binds to the problematic expression, in which case 5655 // show the range of the expression. 5656 SourceRange range = (i < e-1) ? refVars[i+1]->getSourceRange() 5657 : stackE->getSourceRange(); 5658 S.Diag(VD->getLocation(), diag::note_ref_var_local_bind) 5659 << VD->getDeclName() << range; 5660 } 5661 } 5662 5663 /// EvalAddr - EvalAddr and EvalVal are mutually recursive functions that 5664 /// check if the expression in a return statement evaluates to an address 5665 /// to a location on the stack, a local block, an address of a label, or a 5666 /// reference to local temporary. The recursion is used to traverse the 5667 /// AST of the return expression, with recursion backtracking when we 5668 /// encounter a subexpression that (1) clearly does not lead to one of the 5669 /// above problematic expressions (2) is something we cannot determine leads to 5670 /// a problematic expression based on such local checking. 5671 /// 5672 /// Both EvalAddr and EvalVal follow through reference variables to evaluate 5673 /// the expression that they point to. Such variables are added to the 5674 /// 'refVars' vector so that we know what the reference variable "trail" was. 5675 /// 5676 /// EvalAddr processes expressions that are pointers that are used as 5677 /// references (and not L-values). EvalVal handles all other values. 5678 /// At the base case of the recursion is a check for the above problematic 5679 /// expressions. 5680 /// 5681 /// This implementation handles: 5682 /// 5683 /// * pointer-to-pointer casts 5684 /// * implicit conversions from array references to pointers 5685 /// * taking the address of fields 5686 /// * arbitrary interplay between "&" and "*" operators 5687 /// * pointer arithmetic from an address of a stack variable 5688 /// * taking the address of an array element where the array is on the stack 5689 static Expr *EvalAddr(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars, 5690 Decl *ParentDecl) { 5691 if (E->isTypeDependent()) 5692 return nullptr; 5693 5694 // We should only be called for evaluating pointer expressions. 5695 assert((E->getType()->isAnyPointerType() || 5696 E->getType()->isBlockPointerType() || 5697 E->getType()->isObjCQualifiedIdType()) && 5698 "EvalAddr only works on pointers"); 5699 5700 E = E->IgnoreParens(); 5701 5702 // Our "symbolic interpreter" is just a dispatch off the currently 5703 // viewed AST node. We then recursively traverse the AST by calling 5704 // EvalAddr and EvalVal appropriately. 5705 switch (E->getStmtClass()) { 5706 case Stmt::DeclRefExprClass: { 5707 DeclRefExpr *DR = cast<DeclRefExpr>(E); 5708 5709 // If we leave the immediate function, the lifetime isn't about to end. 5710 if (DR->refersToEnclosingVariableOrCapture()) 5711 return nullptr; 5712 5713 if (VarDecl *V = dyn_cast<VarDecl>(DR->getDecl())) 5714 // If this is a reference variable, follow through to the expression that 5715 // it points to. 5716 if (V->hasLocalStorage() && 5717 V->getType()->isReferenceType() && V->hasInit()) { 5718 // Add the reference variable to the "trail". 5719 refVars.push_back(DR); 5720 return EvalAddr(V->getInit(), refVars, ParentDecl); 5721 } 5722 5723 return nullptr; 5724 } 5725 5726 case Stmt::UnaryOperatorClass: { 5727 // The only unary operator that make sense to handle here 5728 // is AddrOf. All others don't make sense as pointers. 5729 UnaryOperator *U = cast<UnaryOperator>(E); 5730 5731 if (U->getOpcode() == UO_AddrOf) 5732 return EvalVal(U->getSubExpr(), refVars, ParentDecl); 5733 else 5734 return nullptr; 5735 } 5736 5737 case Stmt::BinaryOperatorClass: { 5738 // Handle pointer arithmetic. All other binary operators are not valid 5739 // in this context. 5740 BinaryOperator *B = cast<BinaryOperator>(E); 5741 BinaryOperatorKind op = B->getOpcode(); 5742 5743 if (op != BO_Add && op != BO_Sub) 5744 return nullptr; 5745 5746 Expr *Base = B->getLHS(); 5747 5748 // Determine which argument is the real pointer base. It could be 5749 // the RHS argument instead of the LHS. 5750 if (!Base->getType()->isPointerType()) Base = B->getRHS(); 5751 5752 assert (Base->getType()->isPointerType()); 5753 return EvalAddr(Base, refVars, ParentDecl); 5754 } 5755 5756 // For conditional operators we need to see if either the LHS or RHS are 5757 // valid DeclRefExpr*s. If one of them is valid, we return it. 5758 case Stmt::ConditionalOperatorClass: { 5759 ConditionalOperator *C = cast<ConditionalOperator>(E); 5760 5761 // Handle the GNU extension for missing LHS. 5762 // FIXME: That isn't a ConditionalOperator, so doesn't get here. 5763 if (Expr *LHSExpr = C->getLHS()) { 5764 // In C++, we can have a throw-expression, which has 'void' type. 5765 if (!LHSExpr->getType()->isVoidType()) 5766 if (Expr *LHS = EvalAddr(LHSExpr, refVars, ParentDecl)) 5767 return LHS; 5768 } 5769 5770 // In C++, we can have a throw-expression, which has 'void' type. 5771 if (C->getRHS()->getType()->isVoidType()) 5772 return nullptr; 5773 5774 return EvalAddr(C->getRHS(), refVars, ParentDecl); 5775 } 5776 5777 case Stmt::BlockExprClass: 5778 if (cast<BlockExpr>(E)->getBlockDecl()->hasCaptures()) 5779 return E; // local block. 5780 return nullptr; 5781 5782 case Stmt::AddrLabelExprClass: 5783 return E; // address of label. 5784 5785 case Stmt::ExprWithCleanupsClass: 5786 return EvalAddr(cast<ExprWithCleanups>(E)->getSubExpr(), refVars, 5787 ParentDecl); 5788 5789 // For casts, we need to handle conversions from arrays to 5790 // pointer values, and pointer-to-pointer conversions. 5791 case Stmt::ImplicitCastExprClass: 5792 case Stmt::CStyleCastExprClass: 5793 case Stmt::CXXFunctionalCastExprClass: 5794 case Stmt::ObjCBridgedCastExprClass: 5795 case Stmt::CXXStaticCastExprClass: 5796 case Stmt::CXXDynamicCastExprClass: 5797 case Stmt::CXXConstCastExprClass: 5798 case Stmt::CXXReinterpretCastExprClass: { 5799 Expr* SubExpr = cast<CastExpr>(E)->getSubExpr(); 5800 switch (cast<CastExpr>(E)->getCastKind()) { 5801 case CK_LValueToRValue: 5802 case CK_NoOp: 5803 case CK_BaseToDerived: 5804 case CK_DerivedToBase: 5805 case CK_UncheckedDerivedToBase: 5806 case CK_Dynamic: 5807 case CK_CPointerToObjCPointerCast: 5808 case CK_BlockPointerToObjCPointerCast: 5809 case CK_AnyPointerToBlockPointerCast: 5810 return EvalAddr(SubExpr, refVars, ParentDecl); 5811 5812 case CK_ArrayToPointerDecay: 5813 return EvalVal(SubExpr, refVars, ParentDecl); 5814 5815 case CK_BitCast: 5816 if (SubExpr->getType()->isAnyPointerType() || 5817 SubExpr->getType()->isBlockPointerType() || 5818 SubExpr->getType()->isObjCQualifiedIdType()) 5819 return EvalAddr(SubExpr, refVars, ParentDecl); 5820 else 5821 return nullptr; 5822 5823 default: 5824 return nullptr; 5825 } 5826 } 5827 5828 case Stmt::MaterializeTemporaryExprClass: 5829 if (Expr *Result = EvalAddr( 5830 cast<MaterializeTemporaryExpr>(E)->GetTemporaryExpr(), 5831 refVars, ParentDecl)) 5832 return Result; 5833 5834 return E; 5835 5836 // Everything else: we simply don't reason about them. 5837 default: 5838 return nullptr; 5839 } 5840 } 5841 5842 5843 /// EvalVal - This function is complements EvalAddr in the mutual recursion. 5844 /// See the comments for EvalAddr for more details. 5845 static Expr *EvalVal(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars, 5846 Decl *ParentDecl) { 5847 do { 5848 // We should only be called for evaluating non-pointer expressions, or 5849 // expressions with a pointer type that are not used as references but instead 5850 // are l-values (e.g., DeclRefExpr with a pointer type). 5851 5852 // Our "symbolic interpreter" is just a dispatch off the currently 5853 // viewed AST node. We then recursively traverse the AST by calling 5854 // EvalAddr and EvalVal appropriately. 5855 5856 E = E->IgnoreParens(); 5857 switch (E->getStmtClass()) { 5858 case Stmt::ImplicitCastExprClass: { 5859 ImplicitCastExpr *IE = cast<ImplicitCastExpr>(E); 5860 if (IE->getValueKind() == VK_LValue) { 5861 E = IE->getSubExpr(); 5862 continue; 5863 } 5864 return nullptr; 5865 } 5866 5867 case Stmt::ExprWithCleanupsClass: 5868 return EvalVal(cast<ExprWithCleanups>(E)->getSubExpr(), refVars,ParentDecl); 5869 5870 case Stmt::DeclRefExprClass: { 5871 // When we hit a DeclRefExpr we are looking at code that refers to a 5872 // variable's name. If it's not a reference variable we check if it has 5873 // local storage within the function, and if so, return the expression. 5874 DeclRefExpr *DR = cast<DeclRefExpr>(E); 5875 5876 // If we leave the immediate function, the lifetime isn't about to end. 5877 if (DR->refersToEnclosingVariableOrCapture()) 5878 return nullptr; 5879 5880 if (VarDecl *V = dyn_cast<VarDecl>(DR->getDecl())) { 5881 // Check if it refers to itself, e.g. "int& i = i;". 5882 if (V == ParentDecl) 5883 return DR; 5884 5885 if (V->hasLocalStorage()) { 5886 if (!V->getType()->isReferenceType()) 5887 return DR; 5888 5889 // Reference variable, follow through to the expression that 5890 // it points to. 5891 if (V->hasInit()) { 5892 // Add the reference variable to the "trail". 5893 refVars.push_back(DR); 5894 return EvalVal(V->getInit(), refVars, V); 5895 } 5896 } 5897 } 5898 5899 return nullptr; 5900 } 5901 5902 case Stmt::UnaryOperatorClass: { 5903 // The only unary operator that make sense to handle here 5904 // is Deref. All others don't resolve to a "name." This includes 5905 // handling all sorts of rvalues passed to a unary operator. 5906 UnaryOperator *U = cast<UnaryOperator>(E); 5907 5908 if (U->getOpcode() == UO_Deref) 5909 return EvalAddr(U->getSubExpr(), refVars, ParentDecl); 5910 5911 return nullptr; 5912 } 5913 5914 case Stmt::ArraySubscriptExprClass: { 5915 // Array subscripts are potential references to data on the stack. We 5916 // retrieve the DeclRefExpr* for the array variable if it indeed 5917 // has local storage. 5918 return EvalAddr(cast<ArraySubscriptExpr>(E)->getBase(), refVars,ParentDecl); 5919 } 5920 5921 case Stmt::OMPArraySectionExprClass: { 5922 return EvalAddr(cast<OMPArraySectionExpr>(E)->getBase(), refVars, 5923 ParentDecl); 5924 } 5925 5926 case Stmt::ConditionalOperatorClass: { 5927 // For conditional operators we need to see if either the LHS or RHS are 5928 // non-NULL Expr's. If one is non-NULL, we return it. 5929 ConditionalOperator *C = cast<ConditionalOperator>(E); 5930 5931 // Handle the GNU extension for missing LHS. 5932 if (Expr *LHSExpr = C->getLHS()) { 5933 // In C++, we can have a throw-expression, which has 'void' type. 5934 if (!LHSExpr->getType()->isVoidType()) 5935 if (Expr *LHS = EvalVal(LHSExpr, refVars, ParentDecl)) 5936 return LHS; 5937 } 5938 5939 // In C++, we can have a throw-expression, which has 'void' type. 5940 if (C->getRHS()->getType()->isVoidType()) 5941 return nullptr; 5942 5943 return EvalVal(C->getRHS(), refVars, ParentDecl); 5944 } 5945 5946 // Accesses to members are potential references to data on the stack. 5947 case Stmt::MemberExprClass: { 5948 MemberExpr *M = cast<MemberExpr>(E); 5949 5950 // Check for indirect access. We only want direct field accesses. 5951 if (M->isArrow()) 5952 return nullptr; 5953 5954 // Check whether the member type is itself a reference, in which case 5955 // we're not going to refer to the member, but to what the member refers to. 5956 if (M->getMemberDecl()->getType()->isReferenceType()) 5957 return nullptr; 5958 5959 return EvalVal(M->getBase(), refVars, ParentDecl); 5960 } 5961 5962 case Stmt::MaterializeTemporaryExprClass: 5963 if (Expr *Result = EvalVal( 5964 cast<MaterializeTemporaryExpr>(E)->GetTemporaryExpr(), 5965 refVars, ParentDecl)) 5966 return Result; 5967 5968 return E; 5969 5970 default: 5971 // Check that we don't return or take the address of a reference to a 5972 // temporary. This is only useful in C++. 5973 if (!E->isTypeDependent() && E->isRValue()) 5974 return E; 5975 5976 // Everything else: we simply don't reason about them. 5977 return nullptr; 5978 } 5979 } while (true); 5980 } 5981 5982 void 5983 Sema::CheckReturnValExpr(Expr *RetValExp, QualType lhsType, 5984 SourceLocation ReturnLoc, 5985 bool isObjCMethod, 5986 const AttrVec *Attrs, 5987 const FunctionDecl *FD) { 5988 CheckReturnStackAddr(*this, RetValExp, lhsType, ReturnLoc); 5989 5990 // Check if the return value is null but should not be. 5991 if (((Attrs && hasSpecificAttr<ReturnsNonNullAttr>(*Attrs)) || 5992 (!isObjCMethod && isNonNullType(Context, lhsType))) && 5993 CheckNonNullExpr(*this, RetValExp)) 5994 Diag(ReturnLoc, diag::warn_null_ret) 5995 << (isObjCMethod ? 1 : 0) << RetValExp->getSourceRange(); 5996 5997 // C++11 [basic.stc.dynamic.allocation]p4: 5998 // If an allocation function declared with a non-throwing 5999 // exception-specification fails to allocate storage, it shall return 6000 // a null pointer. Any other allocation function that fails to allocate 6001 // storage shall indicate failure only by throwing an exception [...] 6002 if (FD) { 6003 OverloadedOperatorKind Op = FD->getOverloadedOperator(); 6004 if (Op == OO_New || Op == OO_Array_New) { 6005 const FunctionProtoType *Proto 6006 = FD->getType()->castAs<FunctionProtoType>(); 6007 if (!Proto->isNothrow(Context, /*ResultIfDependent*/true) && 6008 CheckNonNullExpr(*this, RetValExp)) 6009 Diag(ReturnLoc, diag::warn_operator_new_returns_null) 6010 << FD << getLangOpts().CPlusPlus11; 6011 } 6012 } 6013 } 6014 6015 //===--- CHECK: Floating-Point comparisons (-Wfloat-equal) ---------------===// 6016 6017 /// Check for comparisons of floating point operands using != and ==. 6018 /// Issue a warning if these are no self-comparisons, as they are not likely 6019 /// to do what the programmer intended. 6020 void Sema::CheckFloatComparison(SourceLocation Loc, Expr* LHS, Expr *RHS) { 6021 Expr* LeftExprSansParen = LHS->IgnoreParenImpCasts(); 6022 Expr* RightExprSansParen = RHS->IgnoreParenImpCasts(); 6023 6024 // Special case: check for x == x (which is OK). 6025 // Do not emit warnings for such cases. 6026 if (DeclRefExpr* DRL = dyn_cast<DeclRefExpr>(LeftExprSansParen)) 6027 if (DeclRefExpr* DRR = dyn_cast<DeclRefExpr>(RightExprSansParen)) 6028 if (DRL->getDecl() == DRR->getDecl()) 6029 return; 6030 6031 6032 // Special case: check for comparisons against literals that can be exactly 6033 // represented by APFloat. In such cases, do not emit a warning. This 6034 // is a heuristic: often comparison against such literals are used to 6035 // detect if a value in a variable has not changed. This clearly can 6036 // lead to false negatives. 6037 if (FloatingLiteral* FLL = dyn_cast<FloatingLiteral>(LeftExprSansParen)) { 6038 if (FLL->isExact()) 6039 return; 6040 } else 6041 if (FloatingLiteral* FLR = dyn_cast<FloatingLiteral>(RightExprSansParen)) 6042 if (FLR->isExact()) 6043 return; 6044 6045 // Check for comparisons with builtin types. 6046 if (CallExpr* CL = dyn_cast<CallExpr>(LeftExprSansParen)) 6047 if (CL->getBuiltinCallee()) 6048 return; 6049 6050 if (CallExpr* CR = dyn_cast<CallExpr>(RightExprSansParen)) 6051 if (CR->getBuiltinCallee()) 6052 return; 6053 6054 // Emit the diagnostic. 6055 Diag(Loc, diag::warn_floatingpoint_eq) 6056 << LHS->getSourceRange() << RHS->getSourceRange(); 6057 } 6058 6059 //===--- CHECK: Integer mixed-sign comparisons (-Wsign-compare) --------===// 6060 //===--- CHECK: Lossy implicit conversions (-Wconversion) --------------===// 6061 6062 namespace { 6063 6064 /// Structure recording the 'active' range of an integer-valued 6065 /// expression. 6066 struct IntRange { 6067 /// The number of bits active in the int. 6068 unsigned Width; 6069 6070 /// True if the int is known not to have negative values. 6071 bool NonNegative; 6072 6073 IntRange(unsigned Width, bool NonNegative) 6074 : Width(Width), NonNegative(NonNegative) 6075 {} 6076 6077 /// Returns the range of the bool type. 6078 static IntRange forBoolType() { 6079 return IntRange(1, true); 6080 } 6081 6082 /// Returns the range of an opaque value of the given integral type. 6083 static IntRange forValueOfType(ASTContext &C, QualType T) { 6084 return forValueOfCanonicalType(C, 6085 T->getCanonicalTypeInternal().getTypePtr()); 6086 } 6087 6088 /// Returns the range of an opaque value of a canonical integral type. 6089 static IntRange forValueOfCanonicalType(ASTContext &C, const Type *T) { 6090 assert(T->isCanonicalUnqualified()); 6091 6092 if (const VectorType *VT = dyn_cast<VectorType>(T)) 6093 T = VT->getElementType().getTypePtr(); 6094 if (const ComplexType *CT = dyn_cast<ComplexType>(T)) 6095 T = CT->getElementType().getTypePtr(); 6096 if (const AtomicType *AT = dyn_cast<AtomicType>(T)) 6097 T = AT->getValueType().getTypePtr(); 6098 6099 // For enum types, use the known bit width of the enumerators. 6100 if (const EnumType *ET = dyn_cast<EnumType>(T)) { 6101 EnumDecl *Enum = ET->getDecl(); 6102 if (!Enum->isCompleteDefinition()) 6103 return IntRange(C.getIntWidth(QualType(T, 0)), false); 6104 6105 unsigned NumPositive = Enum->getNumPositiveBits(); 6106 unsigned NumNegative = Enum->getNumNegativeBits(); 6107 6108 if (NumNegative == 0) 6109 return IntRange(NumPositive, true/*NonNegative*/); 6110 else 6111 return IntRange(std::max(NumPositive + 1, NumNegative), 6112 false/*NonNegative*/); 6113 } 6114 6115 const BuiltinType *BT = cast<BuiltinType>(T); 6116 assert(BT->isInteger()); 6117 6118 return IntRange(C.getIntWidth(QualType(T, 0)), BT->isUnsignedInteger()); 6119 } 6120 6121 /// Returns the "target" range of a canonical integral type, i.e. 6122 /// the range of values expressible in the type. 6123 /// 6124 /// This matches forValueOfCanonicalType except that enums have the 6125 /// full range of their type, not the range of their enumerators. 6126 static IntRange forTargetOfCanonicalType(ASTContext &C, const Type *T) { 6127 assert(T->isCanonicalUnqualified()); 6128 6129 if (const VectorType *VT = dyn_cast<VectorType>(T)) 6130 T = VT->getElementType().getTypePtr(); 6131 if (const ComplexType *CT = dyn_cast<ComplexType>(T)) 6132 T = CT->getElementType().getTypePtr(); 6133 if (const AtomicType *AT = dyn_cast<AtomicType>(T)) 6134 T = AT->getValueType().getTypePtr(); 6135 if (const EnumType *ET = dyn_cast<EnumType>(T)) 6136 T = C.getCanonicalType(ET->getDecl()->getIntegerType()).getTypePtr(); 6137 6138 const BuiltinType *BT = cast<BuiltinType>(T); 6139 assert(BT->isInteger()); 6140 6141 return IntRange(C.getIntWidth(QualType(T, 0)), BT->isUnsignedInteger()); 6142 } 6143 6144 /// Returns the supremum of two ranges: i.e. their conservative merge. 6145 static IntRange join(IntRange L, IntRange R) { 6146 return IntRange(std::max(L.Width, R.Width), 6147 L.NonNegative && R.NonNegative); 6148 } 6149 6150 /// Returns the infinum of two ranges: i.e. their aggressive merge. 6151 static IntRange meet(IntRange L, IntRange R) { 6152 return IntRange(std::min(L.Width, R.Width), 6153 L.NonNegative || R.NonNegative); 6154 } 6155 }; 6156 6157 static IntRange GetValueRange(ASTContext &C, llvm::APSInt &value, 6158 unsigned MaxWidth) { 6159 if (value.isSigned() && value.isNegative()) 6160 return IntRange(value.getMinSignedBits(), false); 6161 6162 if (value.getBitWidth() > MaxWidth) 6163 value = value.trunc(MaxWidth); 6164 6165 // isNonNegative() just checks the sign bit without considering 6166 // signedness. 6167 return IntRange(value.getActiveBits(), true); 6168 } 6169 6170 static IntRange GetValueRange(ASTContext &C, APValue &result, QualType Ty, 6171 unsigned MaxWidth) { 6172 if (result.isInt()) 6173 return GetValueRange(C, result.getInt(), MaxWidth); 6174 6175 if (result.isVector()) { 6176 IntRange R = GetValueRange(C, result.getVectorElt(0), Ty, MaxWidth); 6177 for (unsigned i = 1, e = result.getVectorLength(); i != e; ++i) { 6178 IntRange El = GetValueRange(C, result.getVectorElt(i), Ty, MaxWidth); 6179 R = IntRange::join(R, El); 6180 } 6181 return R; 6182 } 6183 6184 if (result.isComplexInt()) { 6185 IntRange R = GetValueRange(C, result.getComplexIntReal(), MaxWidth); 6186 IntRange I = GetValueRange(C, result.getComplexIntImag(), MaxWidth); 6187 return IntRange::join(R, I); 6188 } 6189 6190 // This can happen with lossless casts to intptr_t of "based" lvalues. 6191 // Assume it might use arbitrary bits. 6192 // FIXME: The only reason we need to pass the type in here is to get 6193 // the sign right on this one case. It would be nice if APValue 6194 // preserved this. 6195 assert(result.isLValue() || result.isAddrLabelDiff()); 6196 return IntRange(MaxWidth, Ty->isUnsignedIntegerOrEnumerationType()); 6197 } 6198 6199 static QualType GetExprType(Expr *E) { 6200 QualType Ty = E->getType(); 6201 if (const AtomicType *AtomicRHS = Ty->getAs<AtomicType>()) 6202 Ty = AtomicRHS->getValueType(); 6203 return Ty; 6204 } 6205 6206 /// Pseudo-evaluate the given integer expression, estimating the 6207 /// range of values it might take. 6208 /// 6209 /// \param MaxWidth - the width to which the value will be truncated 6210 static IntRange GetExprRange(ASTContext &C, Expr *E, unsigned MaxWidth) { 6211 E = E->IgnoreParens(); 6212 6213 // Try a full evaluation first. 6214 Expr::EvalResult result; 6215 if (E->EvaluateAsRValue(result, C)) 6216 return GetValueRange(C, result.Val, GetExprType(E), MaxWidth); 6217 6218 // I think we only want to look through implicit casts here; if the 6219 // user has an explicit widening cast, we should treat the value as 6220 // being of the new, wider type. 6221 if (ImplicitCastExpr *CE = dyn_cast<ImplicitCastExpr>(E)) { 6222 if (CE->getCastKind() == CK_NoOp || CE->getCastKind() == CK_LValueToRValue) 6223 return GetExprRange(C, CE->getSubExpr(), MaxWidth); 6224 6225 IntRange OutputTypeRange = IntRange::forValueOfType(C, GetExprType(CE)); 6226 6227 bool isIntegerCast = (CE->getCastKind() == CK_IntegralCast); 6228 6229 // Assume that non-integer casts can span the full range of the type. 6230 if (!isIntegerCast) 6231 return OutputTypeRange; 6232 6233 IntRange SubRange 6234 = GetExprRange(C, CE->getSubExpr(), 6235 std::min(MaxWidth, OutputTypeRange.Width)); 6236 6237 // Bail out if the subexpr's range is as wide as the cast type. 6238 if (SubRange.Width >= OutputTypeRange.Width) 6239 return OutputTypeRange; 6240 6241 // Otherwise, we take the smaller width, and we're non-negative if 6242 // either the output type or the subexpr is. 6243 return IntRange(SubRange.Width, 6244 SubRange.NonNegative || OutputTypeRange.NonNegative); 6245 } 6246 6247 if (ConditionalOperator *CO = dyn_cast<ConditionalOperator>(E)) { 6248 // If we can fold the condition, just take that operand. 6249 bool CondResult; 6250 if (CO->getCond()->EvaluateAsBooleanCondition(CondResult, C)) 6251 return GetExprRange(C, CondResult ? CO->getTrueExpr() 6252 : CO->getFalseExpr(), 6253 MaxWidth); 6254 6255 // Otherwise, conservatively merge. 6256 IntRange L = GetExprRange(C, CO->getTrueExpr(), MaxWidth); 6257 IntRange R = GetExprRange(C, CO->getFalseExpr(), MaxWidth); 6258 return IntRange::join(L, R); 6259 } 6260 6261 if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) { 6262 switch (BO->getOpcode()) { 6263 6264 // Boolean-valued operations are single-bit and positive. 6265 case BO_LAnd: 6266 case BO_LOr: 6267 case BO_LT: 6268 case BO_GT: 6269 case BO_LE: 6270 case BO_GE: 6271 case BO_EQ: 6272 case BO_NE: 6273 return IntRange::forBoolType(); 6274 6275 // The type of the assignments is the type of the LHS, so the RHS 6276 // is not necessarily the same type. 6277 case BO_MulAssign: 6278 case BO_DivAssign: 6279 case BO_RemAssign: 6280 case BO_AddAssign: 6281 case BO_SubAssign: 6282 case BO_XorAssign: 6283 case BO_OrAssign: 6284 // TODO: bitfields? 6285 return IntRange::forValueOfType(C, GetExprType(E)); 6286 6287 // Simple assignments just pass through the RHS, which will have 6288 // been coerced to the LHS type. 6289 case BO_Assign: 6290 // TODO: bitfields? 6291 return GetExprRange(C, BO->getRHS(), MaxWidth); 6292 6293 // Operations with opaque sources are black-listed. 6294 case BO_PtrMemD: 6295 case BO_PtrMemI: 6296 return IntRange::forValueOfType(C, GetExprType(E)); 6297 6298 // Bitwise-and uses the *infinum* of the two source ranges. 6299 case BO_And: 6300 case BO_AndAssign: 6301 return IntRange::meet(GetExprRange(C, BO->getLHS(), MaxWidth), 6302 GetExprRange(C, BO->getRHS(), MaxWidth)); 6303 6304 // Left shift gets black-listed based on a judgement call. 6305 case BO_Shl: 6306 // ...except that we want to treat '1 << (blah)' as logically 6307 // positive. It's an important idiom. 6308 if (IntegerLiteral *I 6309 = dyn_cast<IntegerLiteral>(BO->getLHS()->IgnoreParenCasts())) { 6310 if (I->getValue() == 1) { 6311 IntRange R = IntRange::forValueOfType(C, GetExprType(E)); 6312 return IntRange(R.Width, /*NonNegative*/ true); 6313 } 6314 } 6315 // fallthrough 6316 6317 case BO_ShlAssign: 6318 return IntRange::forValueOfType(C, GetExprType(E)); 6319 6320 // Right shift by a constant can narrow its left argument. 6321 case BO_Shr: 6322 case BO_ShrAssign: { 6323 IntRange L = GetExprRange(C, BO->getLHS(), MaxWidth); 6324 6325 // If the shift amount is a positive constant, drop the width by 6326 // that much. 6327 llvm::APSInt shift; 6328 if (BO->getRHS()->isIntegerConstantExpr(shift, C) && 6329 shift.isNonNegative()) { 6330 unsigned zext = shift.getZExtValue(); 6331 if (zext >= L.Width) 6332 L.Width = (L.NonNegative ? 0 : 1); 6333 else 6334 L.Width -= zext; 6335 } 6336 6337 return L; 6338 } 6339 6340 // Comma acts as its right operand. 6341 case BO_Comma: 6342 return GetExprRange(C, BO->getRHS(), MaxWidth); 6343 6344 // Black-list pointer subtractions. 6345 case BO_Sub: 6346 if (BO->getLHS()->getType()->isPointerType()) 6347 return IntRange::forValueOfType(C, GetExprType(E)); 6348 break; 6349 6350 // The width of a division result is mostly determined by the size 6351 // of the LHS. 6352 case BO_Div: { 6353 // Don't 'pre-truncate' the operands. 6354 unsigned opWidth = C.getIntWidth(GetExprType(E)); 6355 IntRange L = GetExprRange(C, BO->getLHS(), opWidth); 6356 6357 // If the divisor is constant, use that. 6358 llvm::APSInt divisor; 6359 if (BO->getRHS()->isIntegerConstantExpr(divisor, C)) { 6360 unsigned log2 = divisor.logBase2(); // floor(log_2(divisor)) 6361 if (log2 >= L.Width) 6362 L.Width = (L.NonNegative ? 0 : 1); 6363 else 6364 L.Width = std::min(L.Width - log2, MaxWidth); 6365 return L; 6366 } 6367 6368 // Otherwise, just use the LHS's width. 6369 IntRange R = GetExprRange(C, BO->getRHS(), opWidth); 6370 return IntRange(L.Width, L.NonNegative && R.NonNegative); 6371 } 6372 6373 // The result of a remainder can't be larger than the result of 6374 // either side. 6375 case BO_Rem: { 6376 // Don't 'pre-truncate' the operands. 6377 unsigned opWidth = C.getIntWidth(GetExprType(E)); 6378 IntRange L = GetExprRange(C, BO->getLHS(), opWidth); 6379 IntRange R = GetExprRange(C, BO->getRHS(), opWidth); 6380 6381 IntRange meet = IntRange::meet(L, R); 6382 meet.Width = std::min(meet.Width, MaxWidth); 6383 return meet; 6384 } 6385 6386 // The default behavior is okay for these. 6387 case BO_Mul: 6388 case BO_Add: 6389 case BO_Xor: 6390 case BO_Or: 6391 break; 6392 } 6393 6394 // The default case is to treat the operation as if it were closed 6395 // on the narrowest type that encompasses both operands. 6396 IntRange L = GetExprRange(C, BO->getLHS(), MaxWidth); 6397 IntRange R = GetExprRange(C, BO->getRHS(), MaxWidth); 6398 return IntRange::join(L, R); 6399 } 6400 6401 if (UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) { 6402 switch (UO->getOpcode()) { 6403 // Boolean-valued operations are white-listed. 6404 case UO_LNot: 6405 return IntRange::forBoolType(); 6406 6407 // Operations with opaque sources are black-listed. 6408 case UO_Deref: 6409 case UO_AddrOf: // should be impossible 6410 return IntRange::forValueOfType(C, GetExprType(E)); 6411 6412 default: 6413 return GetExprRange(C, UO->getSubExpr(), MaxWidth); 6414 } 6415 } 6416 6417 if (OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(E)) 6418 return GetExprRange(C, OVE->getSourceExpr(), MaxWidth); 6419 6420 if (FieldDecl *BitField = E->getSourceBitField()) 6421 return IntRange(BitField->getBitWidthValue(C), 6422 BitField->getType()->isUnsignedIntegerOrEnumerationType()); 6423 6424 return IntRange::forValueOfType(C, GetExprType(E)); 6425 } 6426 6427 static IntRange GetExprRange(ASTContext &C, Expr *E) { 6428 return GetExprRange(C, E, C.getIntWidth(GetExprType(E))); 6429 } 6430 6431 /// Checks whether the given value, which currently has the given 6432 /// source semantics, has the same value when coerced through the 6433 /// target semantics. 6434 static bool IsSameFloatAfterCast(const llvm::APFloat &value, 6435 const llvm::fltSemantics &Src, 6436 const llvm::fltSemantics &Tgt) { 6437 llvm::APFloat truncated = value; 6438 6439 bool ignored; 6440 truncated.convert(Src, llvm::APFloat::rmNearestTiesToEven, &ignored); 6441 truncated.convert(Tgt, llvm::APFloat::rmNearestTiesToEven, &ignored); 6442 6443 return truncated.bitwiseIsEqual(value); 6444 } 6445 6446 /// Checks whether the given value, which currently has the given 6447 /// source semantics, has the same value when coerced through the 6448 /// target semantics. 6449 /// 6450 /// The value might be a vector of floats (or a complex number). 6451 static bool IsSameFloatAfterCast(const APValue &value, 6452 const llvm::fltSemantics &Src, 6453 const llvm::fltSemantics &Tgt) { 6454 if (value.isFloat()) 6455 return IsSameFloatAfterCast(value.getFloat(), Src, Tgt); 6456 6457 if (value.isVector()) { 6458 for (unsigned i = 0, e = value.getVectorLength(); i != e; ++i) 6459 if (!IsSameFloatAfterCast(value.getVectorElt(i), Src, Tgt)) 6460 return false; 6461 return true; 6462 } 6463 6464 assert(value.isComplexFloat()); 6465 return (IsSameFloatAfterCast(value.getComplexFloatReal(), Src, Tgt) && 6466 IsSameFloatAfterCast(value.getComplexFloatImag(), Src, Tgt)); 6467 } 6468 6469 static void AnalyzeImplicitConversions(Sema &S, Expr *E, SourceLocation CC); 6470 6471 static bool IsZero(Sema &S, Expr *E) { 6472 // Suppress cases where we are comparing against an enum constant. 6473 if (const DeclRefExpr *DR = 6474 dyn_cast<DeclRefExpr>(E->IgnoreParenImpCasts())) 6475 if (isa<EnumConstantDecl>(DR->getDecl())) 6476 return false; 6477 6478 // Suppress cases where the '0' value is expanded from a macro. 6479 if (E->getLocStart().isMacroID()) 6480 return false; 6481 6482 llvm::APSInt Value; 6483 return E->isIntegerConstantExpr(Value, S.Context) && Value == 0; 6484 } 6485 6486 static bool HasEnumType(Expr *E) { 6487 // Strip off implicit integral promotions. 6488 while (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) { 6489 if (ICE->getCastKind() != CK_IntegralCast && 6490 ICE->getCastKind() != CK_NoOp) 6491 break; 6492 E = ICE->getSubExpr(); 6493 } 6494 6495 return E->getType()->isEnumeralType(); 6496 } 6497 6498 static void CheckTrivialUnsignedComparison(Sema &S, BinaryOperator *E) { 6499 // Disable warning in template instantiations. 6500 if (!S.ActiveTemplateInstantiations.empty()) 6501 return; 6502 6503 BinaryOperatorKind op = E->getOpcode(); 6504 if (E->isValueDependent()) 6505 return; 6506 6507 if (op == BO_LT && IsZero(S, E->getRHS())) { 6508 S.Diag(E->getOperatorLoc(), diag::warn_lunsigned_always_true_comparison) 6509 << "< 0" << "false" << HasEnumType(E->getLHS()) 6510 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); 6511 } else if (op == BO_GE && IsZero(S, E->getRHS())) { 6512 S.Diag(E->getOperatorLoc(), diag::warn_lunsigned_always_true_comparison) 6513 << ">= 0" << "true" << HasEnumType(E->getLHS()) 6514 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); 6515 } else if (op == BO_GT && IsZero(S, E->getLHS())) { 6516 S.Diag(E->getOperatorLoc(), diag::warn_runsigned_always_true_comparison) 6517 << "0 >" << "false" << HasEnumType(E->getRHS()) 6518 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); 6519 } else if (op == BO_LE && IsZero(S, E->getLHS())) { 6520 S.Diag(E->getOperatorLoc(), diag::warn_runsigned_always_true_comparison) 6521 << "0 <=" << "true" << HasEnumType(E->getRHS()) 6522 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); 6523 } 6524 } 6525 6526 static void DiagnoseOutOfRangeComparison(Sema &S, BinaryOperator *E, 6527 Expr *Constant, Expr *Other, 6528 llvm::APSInt Value, 6529 bool RhsConstant) { 6530 // Disable warning in template instantiations. 6531 if (!S.ActiveTemplateInstantiations.empty()) 6532 return; 6533 6534 // TODO: Investigate using GetExprRange() to get tighter bounds 6535 // on the bit ranges. 6536 QualType OtherT = Other->getType(); 6537 if (const auto *AT = OtherT->getAs<AtomicType>()) 6538 OtherT = AT->getValueType(); 6539 IntRange OtherRange = IntRange::forValueOfType(S.Context, OtherT); 6540 unsigned OtherWidth = OtherRange.Width; 6541 6542 bool OtherIsBooleanType = Other->isKnownToHaveBooleanValue(); 6543 6544 // 0 values are handled later by CheckTrivialUnsignedComparison(). 6545 if ((Value == 0) && (!OtherIsBooleanType)) 6546 return; 6547 6548 BinaryOperatorKind op = E->getOpcode(); 6549 bool IsTrue = true; 6550 6551 // Used for diagnostic printout. 6552 enum { 6553 LiteralConstant = 0, 6554 CXXBoolLiteralTrue, 6555 CXXBoolLiteralFalse 6556 } LiteralOrBoolConstant = LiteralConstant; 6557 6558 if (!OtherIsBooleanType) { 6559 QualType ConstantT = Constant->getType(); 6560 QualType CommonT = E->getLHS()->getType(); 6561 6562 if (S.Context.hasSameUnqualifiedType(OtherT, ConstantT)) 6563 return; 6564 assert((OtherT->isIntegerType() && ConstantT->isIntegerType()) && 6565 "comparison with non-integer type"); 6566 6567 bool ConstantSigned = ConstantT->isSignedIntegerType(); 6568 bool CommonSigned = CommonT->isSignedIntegerType(); 6569 6570 bool EqualityOnly = false; 6571 6572 if (CommonSigned) { 6573 // The common type is signed, therefore no signed to unsigned conversion. 6574 if (!OtherRange.NonNegative) { 6575 // Check that the constant is representable in type OtherT. 6576 if (ConstantSigned) { 6577 if (OtherWidth >= Value.getMinSignedBits()) 6578 return; 6579 } else { // !ConstantSigned 6580 if (OtherWidth >= Value.getActiveBits() + 1) 6581 return; 6582 } 6583 } else { // !OtherSigned 6584 // Check that the constant is representable in type OtherT. 6585 // Negative values are out of range. 6586 if (ConstantSigned) { 6587 if (Value.isNonNegative() && OtherWidth >= Value.getActiveBits()) 6588 return; 6589 } else { // !ConstantSigned 6590 if (OtherWidth >= Value.getActiveBits()) 6591 return; 6592 } 6593 } 6594 } else { // !CommonSigned 6595 if (OtherRange.NonNegative) { 6596 if (OtherWidth >= Value.getActiveBits()) 6597 return; 6598 } else { // OtherSigned 6599 assert(!ConstantSigned && 6600 "Two signed types converted to unsigned types."); 6601 // Check to see if the constant is representable in OtherT. 6602 if (OtherWidth > Value.getActiveBits()) 6603 return; 6604 // Check to see if the constant is equivalent to a negative value 6605 // cast to CommonT. 6606 if (S.Context.getIntWidth(ConstantT) == 6607 S.Context.getIntWidth(CommonT) && 6608 Value.isNegative() && Value.getMinSignedBits() <= OtherWidth) 6609 return; 6610 // The constant value rests between values that OtherT can represent 6611 // after conversion. Relational comparison still works, but equality 6612 // comparisons will be tautological. 6613 EqualityOnly = true; 6614 } 6615 } 6616 6617 bool PositiveConstant = !ConstantSigned || Value.isNonNegative(); 6618 6619 if (op == BO_EQ || op == BO_NE) { 6620 IsTrue = op == BO_NE; 6621 } else if (EqualityOnly) { 6622 return; 6623 } else if (RhsConstant) { 6624 if (op == BO_GT || op == BO_GE) 6625 IsTrue = !PositiveConstant; 6626 else // op == BO_LT || op == BO_LE 6627 IsTrue = PositiveConstant; 6628 } else { 6629 if (op == BO_LT || op == BO_LE) 6630 IsTrue = !PositiveConstant; 6631 else // op == BO_GT || op == BO_GE 6632 IsTrue = PositiveConstant; 6633 } 6634 } else { 6635 // Other isKnownToHaveBooleanValue 6636 enum CompareBoolWithConstantResult { AFals, ATrue, Unkwn }; 6637 enum ConstantValue { LT_Zero, Zero, One, GT_One, SizeOfConstVal }; 6638 enum ConstantSide { Lhs, Rhs, SizeOfConstSides }; 6639 6640 static const struct LinkedConditions { 6641 CompareBoolWithConstantResult BO_LT_OP[SizeOfConstSides][SizeOfConstVal]; 6642 CompareBoolWithConstantResult BO_GT_OP[SizeOfConstSides][SizeOfConstVal]; 6643 CompareBoolWithConstantResult BO_LE_OP[SizeOfConstSides][SizeOfConstVal]; 6644 CompareBoolWithConstantResult BO_GE_OP[SizeOfConstSides][SizeOfConstVal]; 6645 CompareBoolWithConstantResult BO_EQ_OP[SizeOfConstSides][SizeOfConstVal]; 6646 CompareBoolWithConstantResult BO_NE_OP[SizeOfConstSides][SizeOfConstVal]; 6647 6648 } TruthTable = { 6649 // Constant on LHS. | Constant on RHS. | 6650 // LT_Zero| Zero | One |GT_One| LT_Zero| Zero | One |GT_One| 6651 { { ATrue, Unkwn, AFals, AFals }, { AFals, AFals, Unkwn, ATrue } }, 6652 { { AFals, AFals, Unkwn, ATrue }, { ATrue, Unkwn, AFals, AFals } }, 6653 { { ATrue, ATrue, Unkwn, AFals }, { AFals, Unkwn, ATrue, ATrue } }, 6654 { { AFals, Unkwn, ATrue, ATrue }, { ATrue, ATrue, Unkwn, AFals } }, 6655 { { AFals, Unkwn, Unkwn, AFals }, { AFals, Unkwn, Unkwn, AFals } }, 6656 { { ATrue, Unkwn, Unkwn, ATrue }, { ATrue, Unkwn, Unkwn, ATrue } } 6657 }; 6658 6659 bool ConstantIsBoolLiteral = isa<CXXBoolLiteralExpr>(Constant); 6660 6661 enum ConstantValue ConstVal = Zero; 6662 if (Value.isUnsigned() || Value.isNonNegative()) { 6663 if (Value == 0) { 6664 LiteralOrBoolConstant = 6665 ConstantIsBoolLiteral ? CXXBoolLiteralFalse : LiteralConstant; 6666 ConstVal = Zero; 6667 } else if (Value == 1) { 6668 LiteralOrBoolConstant = 6669 ConstantIsBoolLiteral ? CXXBoolLiteralTrue : LiteralConstant; 6670 ConstVal = One; 6671 } else { 6672 LiteralOrBoolConstant = LiteralConstant; 6673 ConstVal = GT_One; 6674 } 6675 } else { 6676 ConstVal = LT_Zero; 6677 } 6678 6679 CompareBoolWithConstantResult CmpRes; 6680 6681 switch (op) { 6682 case BO_LT: 6683 CmpRes = TruthTable.BO_LT_OP[RhsConstant][ConstVal]; 6684 break; 6685 case BO_GT: 6686 CmpRes = TruthTable.BO_GT_OP[RhsConstant][ConstVal]; 6687 break; 6688 case BO_LE: 6689 CmpRes = TruthTable.BO_LE_OP[RhsConstant][ConstVal]; 6690 break; 6691 case BO_GE: 6692 CmpRes = TruthTable.BO_GE_OP[RhsConstant][ConstVal]; 6693 break; 6694 case BO_EQ: 6695 CmpRes = TruthTable.BO_EQ_OP[RhsConstant][ConstVal]; 6696 break; 6697 case BO_NE: 6698 CmpRes = TruthTable.BO_NE_OP[RhsConstant][ConstVal]; 6699 break; 6700 default: 6701 CmpRes = Unkwn; 6702 break; 6703 } 6704 6705 if (CmpRes == AFals) { 6706 IsTrue = false; 6707 } else if (CmpRes == ATrue) { 6708 IsTrue = true; 6709 } else { 6710 return; 6711 } 6712 } 6713 6714 // If this is a comparison to an enum constant, include that 6715 // constant in the diagnostic. 6716 const EnumConstantDecl *ED = nullptr; 6717 if (const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(Constant)) 6718 ED = dyn_cast<EnumConstantDecl>(DR->getDecl()); 6719 6720 SmallString<64> PrettySourceValue; 6721 llvm::raw_svector_ostream OS(PrettySourceValue); 6722 if (ED) 6723 OS << '\'' << *ED << "' (" << Value << ")"; 6724 else 6725 OS << Value; 6726 6727 S.DiagRuntimeBehavior( 6728 E->getOperatorLoc(), E, 6729 S.PDiag(diag::warn_out_of_range_compare) 6730 << OS.str() << LiteralOrBoolConstant 6731 << OtherT << (OtherIsBooleanType && !OtherT->isBooleanType()) << IsTrue 6732 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange()); 6733 } 6734 6735 /// Analyze the operands of the given comparison. Implements the 6736 /// fallback case from AnalyzeComparison. 6737 static void AnalyzeImpConvsInComparison(Sema &S, BinaryOperator *E) { 6738 AnalyzeImplicitConversions(S, E->getLHS(), E->getOperatorLoc()); 6739 AnalyzeImplicitConversions(S, E->getRHS(), E->getOperatorLoc()); 6740 } 6741 6742 /// \brief Implements -Wsign-compare. 6743 /// 6744 /// \param E the binary operator to check for warnings 6745 static void AnalyzeComparison(Sema &S, BinaryOperator *E) { 6746 // The type the comparison is being performed in. 6747 QualType T = E->getLHS()->getType(); 6748 6749 // Only analyze comparison operators where both sides have been converted to 6750 // the same type. 6751 if (!S.Context.hasSameUnqualifiedType(T, E->getRHS()->getType())) 6752 return AnalyzeImpConvsInComparison(S, E); 6753 6754 // Don't analyze value-dependent comparisons directly. 6755 if (E->isValueDependent()) 6756 return AnalyzeImpConvsInComparison(S, E); 6757 6758 Expr *LHS = E->getLHS()->IgnoreParenImpCasts(); 6759 Expr *RHS = E->getRHS()->IgnoreParenImpCasts(); 6760 6761 bool IsComparisonConstant = false; 6762 6763 // Check whether an integer constant comparison results in a value 6764 // of 'true' or 'false'. 6765 if (T->isIntegralType(S.Context)) { 6766 llvm::APSInt RHSValue; 6767 bool IsRHSIntegralLiteral = 6768 RHS->isIntegerConstantExpr(RHSValue, S.Context); 6769 llvm::APSInt LHSValue; 6770 bool IsLHSIntegralLiteral = 6771 LHS->isIntegerConstantExpr(LHSValue, S.Context); 6772 if (IsRHSIntegralLiteral && !IsLHSIntegralLiteral) 6773 DiagnoseOutOfRangeComparison(S, E, RHS, LHS, RHSValue, true); 6774 else if (!IsRHSIntegralLiteral && IsLHSIntegralLiteral) 6775 DiagnoseOutOfRangeComparison(S, E, LHS, RHS, LHSValue, false); 6776 else 6777 IsComparisonConstant = 6778 (IsRHSIntegralLiteral && IsLHSIntegralLiteral); 6779 } else if (!T->hasUnsignedIntegerRepresentation()) 6780 IsComparisonConstant = E->isIntegerConstantExpr(S.Context); 6781 6782 // We don't do anything special if this isn't an unsigned integral 6783 // comparison: we're only interested in integral comparisons, and 6784 // signed comparisons only happen in cases we don't care to warn about. 6785 // 6786 // We also don't care about value-dependent expressions or expressions 6787 // whose result is a constant. 6788 if (!T->hasUnsignedIntegerRepresentation() || IsComparisonConstant) 6789 return AnalyzeImpConvsInComparison(S, E); 6790 6791 // Check to see if one of the (unmodified) operands is of different 6792 // signedness. 6793 Expr *signedOperand, *unsignedOperand; 6794 if (LHS->getType()->hasSignedIntegerRepresentation()) { 6795 assert(!RHS->getType()->hasSignedIntegerRepresentation() && 6796 "unsigned comparison between two signed integer expressions?"); 6797 signedOperand = LHS; 6798 unsignedOperand = RHS; 6799 } else if (RHS->getType()->hasSignedIntegerRepresentation()) { 6800 signedOperand = RHS; 6801 unsignedOperand = LHS; 6802 } else { 6803 CheckTrivialUnsignedComparison(S, E); 6804 return AnalyzeImpConvsInComparison(S, E); 6805 } 6806 6807 // Otherwise, calculate the effective range of the signed operand. 6808 IntRange signedRange = GetExprRange(S.Context, signedOperand); 6809 6810 // Go ahead and analyze implicit conversions in the operands. Note 6811 // that we skip the implicit conversions on both sides. 6812 AnalyzeImplicitConversions(S, LHS, E->getOperatorLoc()); 6813 AnalyzeImplicitConversions(S, RHS, E->getOperatorLoc()); 6814 6815 // If the signed range is non-negative, -Wsign-compare won't fire, 6816 // but we should still check for comparisons which are always true 6817 // or false. 6818 if (signedRange.NonNegative) 6819 return CheckTrivialUnsignedComparison(S, E); 6820 6821 // For (in)equality comparisons, if the unsigned operand is a 6822 // constant which cannot collide with a overflowed signed operand, 6823 // then reinterpreting the signed operand as unsigned will not 6824 // change the result of the comparison. 6825 if (E->isEqualityOp()) { 6826 unsigned comparisonWidth = S.Context.getIntWidth(T); 6827 IntRange unsignedRange = GetExprRange(S.Context, unsignedOperand); 6828 6829 // We should never be unable to prove that the unsigned operand is 6830 // non-negative. 6831 assert(unsignedRange.NonNegative && "unsigned range includes negative?"); 6832 6833 if (unsignedRange.Width < comparisonWidth) 6834 return; 6835 } 6836 6837 S.DiagRuntimeBehavior(E->getOperatorLoc(), E, 6838 S.PDiag(diag::warn_mixed_sign_comparison) 6839 << LHS->getType() << RHS->getType() 6840 << LHS->getSourceRange() << RHS->getSourceRange()); 6841 } 6842 6843 /// Analyzes an attempt to assign the given value to a bitfield. 6844 /// 6845 /// Returns true if there was something fishy about the attempt. 6846 static bool AnalyzeBitFieldAssignment(Sema &S, FieldDecl *Bitfield, Expr *Init, 6847 SourceLocation InitLoc) { 6848 assert(Bitfield->isBitField()); 6849 if (Bitfield->isInvalidDecl()) 6850 return false; 6851 6852 // White-list bool bitfields. 6853 if (Bitfield->getType()->isBooleanType()) 6854 return false; 6855 6856 // Ignore value- or type-dependent expressions. 6857 if (Bitfield->getBitWidth()->isValueDependent() || 6858 Bitfield->getBitWidth()->isTypeDependent() || 6859 Init->isValueDependent() || 6860 Init->isTypeDependent()) 6861 return false; 6862 6863 Expr *OriginalInit = Init->IgnoreParenImpCasts(); 6864 6865 llvm::APSInt Value; 6866 if (!OriginalInit->EvaluateAsInt(Value, S.Context, Expr::SE_AllowSideEffects)) 6867 return false; 6868 6869 unsigned OriginalWidth = Value.getBitWidth(); 6870 unsigned FieldWidth = Bitfield->getBitWidthValue(S.Context); 6871 6872 if (OriginalWidth <= FieldWidth) 6873 return false; 6874 6875 // Compute the value which the bitfield will contain. 6876 llvm::APSInt TruncatedValue = Value.trunc(FieldWidth); 6877 TruncatedValue.setIsSigned(Bitfield->getType()->isSignedIntegerType()); 6878 6879 // Check whether the stored value is equal to the original value. 6880 TruncatedValue = TruncatedValue.extend(OriginalWidth); 6881 if (llvm::APSInt::isSameValue(Value, TruncatedValue)) 6882 return false; 6883 6884 // Special-case bitfields of width 1: booleans are naturally 0/1, and 6885 // therefore don't strictly fit into a signed bitfield of width 1. 6886 if (FieldWidth == 1 && Value == 1) 6887 return false; 6888 6889 std::string PrettyValue = Value.toString(10); 6890 std::string PrettyTrunc = TruncatedValue.toString(10); 6891 6892 S.Diag(InitLoc, diag::warn_impcast_bitfield_precision_constant) 6893 << PrettyValue << PrettyTrunc << OriginalInit->getType() 6894 << Init->getSourceRange(); 6895 6896 return true; 6897 } 6898 6899 /// Analyze the given simple or compound assignment for warning-worthy 6900 /// operations. 6901 static void AnalyzeAssignment(Sema &S, BinaryOperator *E) { 6902 // Just recurse on the LHS. 6903 AnalyzeImplicitConversions(S, E->getLHS(), E->getOperatorLoc()); 6904 6905 // We want to recurse on the RHS as normal unless we're assigning to 6906 // a bitfield. 6907 if (FieldDecl *Bitfield = E->getLHS()->getSourceBitField()) { 6908 if (AnalyzeBitFieldAssignment(S, Bitfield, E->getRHS(), 6909 E->getOperatorLoc())) { 6910 // Recurse, ignoring any implicit conversions on the RHS. 6911 return AnalyzeImplicitConversions(S, E->getRHS()->IgnoreParenImpCasts(), 6912 E->getOperatorLoc()); 6913 } 6914 } 6915 6916 AnalyzeImplicitConversions(S, E->getRHS(), E->getOperatorLoc()); 6917 } 6918 6919 /// Diagnose an implicit cast; purely a helper for CheckImplicitConversion. 6920 static void DiagnoseImpCast(Sema &S, Expr *E, QualType SourceType, QualType T, 6921 SourceLocation CContext, unsigned diag, 6922 bool pruneControlFlow = false) { 6923 if (pruneControlFlow) { 6924 S.DiagRuntimeBehavior(E->getExprLoc(), E, 6925 S.PDiag(diag) 6926 << SourceType << T << E->getSourceRange() 6927 << SourceRange(CContext)); 6928 return; 6929 } 6930 S.Diag(E->getExprLoc(), diag) 6931 << SourceType << T << E->getSourceRange() << SourceRange(CContext); 6932 } 6933 6934 /// Diagnose an implicit cast; purely a helper for CheckImplicitConversion. 6935 static void DiagnoseImpCast(Sema &S, Expr *E, QualType T, 6936 SourceLocation CContext, unsigned diag, 6937 bool pruneControlFlow = false) { 6938 DiagnoseImpCast(S, E, E->getType(), T, CContext, diag, pruneControlFlow); 6939 } 6940 6941 /// Diagnose an implicit cast from a literal expression. Does not warn when the 6942 /// cast wouldn't lose information. 6943 void DiagnoseFloatingLiteralImpCast(Sema &S, FloatingLiteral *FL, QualType T, 6944 SourceLocation CContext) { 6945 // Try to convert the literal exactly to an integer. If we can, don't warn. 6946 bool isExact = false; 6947 const llvm::APFloat &Value = FL->getValue(); 6948 llvm::APSInt IntegerValue(S.Context.getIntWidth(T), 6949 T->hasUnsignedIntegerRepresentation()); 6950 if (Value.convertToInteger(IntegerValue, 6951 llvm::APFloat::rmTowardZero, &isExact) 6952 == llvm::APFloat::opOK && isExact) 6953 return; 6954 6955 // FIXME: Force the precision of the source value down so we don't print 6956 // digits which are usually useless (we don't really care here if we 6957 // truncate a digit by accident in edge cases). Ideally, APFloat::toString 6958 // would automatically print the shortest representation, but it's a bit 6959 // tricky to implement. 6960 SmallString<16> PrettySourceValue; 6961 unsigned precision = llvm::APFloat::semanticsPrecision(Value.getSemantics()); 6962 precision = (precision * 59 + 195) / 196; 6963 Value.toString(PrettySourceValue, precision); 6964 6965 SmallString<16> PrettyTargetValue; 6966 if (T->isSpecificBuiltinType(BuiltinType::Bool)) 6967 PrettyTargetValue = IntegerValue == 0 ? "false" : "true"; 6968 else 6969 IntegerValue.toString(PrettyTargetValue); 6970 6971 S.Diag(FL->getExprLoc(), diag::warn_impcast_literal_float_to_integer) 6972 << FL->getType() << T.getUnqualifiedType() << PrettySourceValue 6973 << PrettyTargetValue << FL->getSourceRange() << SourceRange(CContext); 6974 } 6975 6976 std::string PrettyPrintInRange(const llvm::APSInt &Value, IntRange Range) { 6977 if (!Range.Width) return "0"; 6978 6979 llvm::APSInt ValueInRange = Value; 6980 ValueInRange.setIsSigned(!Range.NonNegative); 6981 ValueInRange = ValueInRange.trunc(Range.Width); 6982 return ValueInRange.toString(10); 6983 } 6984 6985 static bool IsImplicitBoolFloatConversion(Sema &S, Expr *Ex, bool ToBool) { 6986 if (!isa<ImplicitCastExpr>(Ex)) 6987 return false; 6988 6989 Expr *InnerE = Ex->IgnoreParenImpCasts(); 6990 const Type *Target = S.Context.getCanonicalType(Ex->getType()).getTypePtr(); 6991 const Type *Source = 6992 S.Context.getCanonicalType(InnerE->getType()).getTypePtr(); 6993 if (Target->isDependentType()) 6994 return false; 6995 6996 const BuiltinType *FloatCandidateBT = 6997 dyn_cast<BuiltinType>(ToBool ? Source : Target); 6998 const Type *BoolCandidateType = ToBool ? Target : Source; 6999 7000 return (BoolCandidateType->isSpecificBuiltinType(BuiltinType::Bool) && 7001 FloatCandidateBT && (FloatCandidateBT->isFloatingPoint())); 7002 } 7003 7004 void CheckImplicitArgumentConversions(Sema &S, CallExpr *TheCall, 7005 SourceLocation CC) { 7006 unsigned NumArgs = TheCall->getNumArgs(); 7007 for (unsigned i = 0; i < NumArgs; ++i) { 7008 Expr *CurrA = TheCall->getArg(i); 7009 if (!IsImplicitBoolFloatConversion(S, CurrA, true)) 7010 continue; 7011 7012 bool IsSwapped = ((i > 0) && 7013 IsImplicitBoolFloatConversion(S, TheCall->getArg(i - 1), false)); 7014 IsSwapped |= ((i < (NumArgs - 1)) && 7015 IsImplicitBoolFloatConversion(S, TheCall->getArg(i + 1), false)); 7016 if (IsSwapped) { 7017 // Warn on this floating-point to bool conversion. 7018 DiagnoseImpCast(S, CurrA->IgnoreParenImpCasts(), 7019 CurrA->getType(), CC, 7020 diag::warn_impcast_floating_point_to_bool); 7021 } 7022 } 7023 } 7024 7025 static void DiagnoseNullConversion(Sema &S, Expr *E, QualType T, 7026 SourceLocation CC) { 7027 if (S.Diags.isIgnored(diag::warn_impcast_null_pointer_to_integer, 7028 E->getExprLoc())) 7029 return; 7030 7031 // Check for NULL (GNUNull) or nullptr (CXX11_nullptr). 7032 const Expr::NullPointerConstantKind NullKind = 7033 E->isNullPointerConstant(S.Context, Expr::NPC_ValueDependentIsNotNull); 7034 if (NullKind != Expr::NPCK_GNUNull && NullKind != Expr::NPCK_CXX11_nullptr) 7035 return; 7036 7037 // Return if target type is a safe conversion. 7038 if (T->isAnyPointerType() || T->isBlockPointerType() || 7039 T->isMemberPointerType() || !T->isScalarType() || T->isNullPtrType()) 7040 return; 7041 7042 SourceLocation Loc = E->getSourceRange().getBegin(); 7043 7044 // __null is usually wrapped in a macro. Go up a macro if that is the case. 7045 if (NullKind == Expr::NPCK_GNUNull) { 7046 if (Loc.isMacroID()) 7047 Loc = S.SourceMgr.getImmediateExpansionRange(Loc).first; 7048 } 7049 7050 // Only warn if the null and context location are in the same macro expansion. 7051 if (S.SourceMgr.getFileID(Loc) != S.SourceMgr.getFileID(CC)) 7052 return; 7053 7054 S.Diag(Loc, diag::warn_impcast_null_pointer_to_integer) 7055 << (NullKind == Expr::NPCK_CXX11_nullptr) << T << clang::SourceRange(CC) 7056 << FixItHint::CreateReplacement(Loc, 7057 S.getFixItZeroLiteralForType(T, Loc)); 7058 } 7059 7060 static void checkObjCArrayLiteral(Sema &S, QualType TargetType, 7061 ObjCArrayLiteral *ArrayLiteral); 7062 static void checkObjCDictionaryLiteral(Sema &S, QualType TargetType, 7063 ObjCDictionaryLiteral *DictionaryLiteral); 7064 7065 /// Check a single element within a collection literal against the 7066 /// target element type. 7067 static void checkObjCCollectionLiteralElement(Sema &S, 7068 QualType TargetElementType, 7069 Expr *Element, 7070 unsigned ElementKind) { 7071 // Skip a bitcast to 'id' or qualified 'id'. 7072 if (auto ICE = dyn_cast<ImplicitCastExpr>(Element)) { 7073 if (ICE->getCastKind() == CK_BitCast && 7074 ICE->getSubExpr()->getType()->getAs<ObjCObjectPointerType>()) 7075 Element = ICE->getSubExpr(); 7076 } 7077 7078 QualType ElementType = Element->getType(); 7079 ExprResult ElementResult(Element); 7080 if (ElementType->getAs<ObjCObjectPointerType>() && 7081 S.CheckSingleAssignmentConstraints(TargetElementType, 7082 ElementResult, 7083 false, false) 7084 != Sema::Compatible) { 7085 S.Diag(Element->getLocStart(), 7086 diag::warn_objc_collection_literal_element) 7087 << ElementType << ElementKind << TargetElementType 7088 << Element->getSourceRange(); 7089 } 7090 7091 if (auto ArrayLiteral = dyn_cast<ObjCArrayLiteral>(Element)) 7092 checkObjCArrayLiteral(S, TargetElementType, ArrayLiteral); 7093 else if (auto DictionaryLiteral = dyn_cast<ObjCDictionaryLiteral>(Element)) 7094 checkObjCDictionaryLiteral(S, TargetElementType, DictionaryLiteral); 7095 } 7096 7097 /// Check an Objective-C array literal being converted to the given 7098 /// target type. 7099 static void checkObjCArrayLiteral(Sema &S, QualType TargetType, 7100 ObjCArrayLiteral *ArrayLiteral) { 7101 if (!S.NSArrayDecl) 7102 return; 7103 7104 const auto *TargetObjCPtr = TargetType->getAs<ObjCObjectPointerType>(); 7105 if (!TargetObjCPtr) 7106 return; 7107 7108 if (TargetObjCPtr->isUnspecialized() || 7109 TargetObjCPtr->getInterfaceDecl()->getCanonicalDecl() 7110 != S.NSArrayDecl->getCanonicalDecl()) 7111 return; 7112 7113 auto TypeArgs = TargetObjCPtr->getTypeArgs(); 7114 if (TypeArgs.size() != 1) 7115 return; 7116 7117 QualType TargetElementType = TypeArgs[0]; 7118 for (unsigned I = 0, N = ArrayLiteral->getNumElements(); I != N; ++I) { 7119 checkObjCCollectionLiteralElement(S, TargetElementType, 7120 ArrayLiteral->getElement(I), 7121 0); 7122 } 7123 } 7124 7125 /// Check an Objective-C dictionary literal being converted to the given 7126 /// target type. 7127 static void checkObjCDictionaryLiteral( 7128 Sema &S, QualType TargetType, 7129 ObjCDictionaryLiteral *DictionaryLiteral) { 7130 if (!S.NSDictionaryDecl) 7131 return; 7132 7133 const auto *TargetObjCPtr = TargetType->getAs<ObjCObjectPointerType>(); 7134 if (!TargetObjCPtr) 7135 return; 7136 7137 if (TargetObjCPtr->isUnspecialized() || 7138 TargetObjCPtr->getInterfaceDecl()->getCanonicalDecl() 7139 != S.NSDictionaryDecl->getCanonicalDecl()) 7140 return; 7141 7142 auto TypeArgs = TargetObjCPtr->getTypeArgs(); 7143 if (TypeArgs.size() != 2) 7144 return; 7145 7146 QualType TargetKeyType = TypeArgs[0]; 7147 QualType TargetObjectType = TypeArgs[1]; 7148 for (unsigned I = 0, N = DictionaryLiteral->getNumElements(); I != N; ++I) { 7149 auto Element = DictionaryLiteral->getKeyValueElement(I); 7150 checkObjCCollectionLiteralElement(S, TargetKeyType, Element.Key, 1); 7151 checkObjCCollectionLiteralElement(S, TargetObjectType, Element.Value, 2); 7152 } 7153 } 7154 7155 void CheckImplicitConversion(Sema &S, Expr *E, QualType T, 7156 SourceLocation CC, bool *ICContext = nullptr) { 7157 if (E->isTypeDependent() || E->isValueDependent()) return; 7158 7159 const Type *Source = S.Context.getCanonicalType(E->getType()).getTypePtr(); 7160 const Type *Target = S.Context.getCanonicalType(T).getTypePtr(); 7161 if (Source == Target) return; 7162 if (Target->isDependentType()) return; 7163 7164 // If the conversion context location is invalid don't complain. We also 7165 // don't want to emit a warning if the issue occurs from the expansion of 7166 // a system macro. The problem is that 'getSpellingLoc()' is slow, so we 7167 // delay this check as long as possible. Once we detect we are in that 7168 // scenario, we just return. 7169 if (CC.isInvalid()) 7170 return; 7171 7172 // Diagnose implicit casts to bool. 7173 if (Target->isSpecificBuiltinType(BuiltinType::Bool)) { 7174 if (isa<StringLiteral>(E)) 7175 // Warn on string literal to bool. Checks for string literals in logical 7176 // and expressions, for instance, assert(0 && "error here"), are 7177 // prevented by a check in AnalyzeImplicitConversions(). 7178 return DiagnoseImpCast(S, E, T, CC, 7179 diag::warn_impcast_string_literal_to_bool); 7180 if (isa<ObjCStringLiteral>(E) || isa<ObjCArrayLiteral>(E) || 7181 isa<ObjCDictionaryLiteral>(E) || isa<ObjCBoxedExpr>(E)) { 7182 // This covers the literal expressions that evaluate to Objective-C 7183 // objects. 7184 return DiagnoseImpCast(S, E, T, CC, 7185 diag::warn_impcast_objective_c_literal_to_bool); 7186 } 7187 if (Source->isPointerType() || Source->canDecayToPointerType()) { 7188 // Warn on pointer to bool conversion that is always true. 7189 S.DiagnoseAlwaysNonNullPointer(E, Expr::NPCK_NotNull, /*IsEqual*/ false, 7190 SourceRange(CC)); 7191 } 7192 } 7193 7194 // Check implicit casts from Objective-C collection literals to specialized 7195 // collection types, e.g., NSArray<NSString *> *. 7196 if (auto *ArrayLiteral = dyn_cast<ObjCArrayLiteral>(E)) 7197 checkObjCArrayLiteral(S, QualType(Target, 0), ArrayLiteral); 7198 else if (auto *DictionaryLiteral = dyn_cast<ObjCDictionaryLiteral>(E)) 7199 checkObjCDictionaryLiteral(S, QualType(Target, 0), DictionaryLiteral); 7200 7201 // Strip vector types. 7202 if (isa<VectorType>(Source)) { 7203 if (!isa<VectorType>(Target)) { 7204 if (S.SourceMgr.isInSystemMacro(CC)) 7205 return; 7206 return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_vector_scalar); 7207 } 7208 7209 // If the vector cast is cast between two vectors of the same size, it is 7210 // a bitcast, not a conversion. 7211 if (S.Context.getTypeSize(Source) == S.Context.getTypeSize(Target)) 7212 return; 7213 7214 Source = cast<VectorType>(Source)->getElementType().getTypePtr(); 7215 Target = cast<VectorType>(Target)->getElementType().getTypePtr(); 7216 } 7217 if (auto VecTy = dyn_cast<VectorType>(Target)) 7218 Target = VecTy->getElementType().getTypePtr(); 7219 7220 // Strip complex types. 7221 if (isa<ComplexType>(Source)) { 7222 if (!isa<ComplexType>(Target)) { 7223 if (S.SourceMgr.isInSystemMacro(CC)) 7224 return; 7225 7226 return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_complex_scalar); 7227 } 7228 7229 Source = cast<ComplexType>(Source)->getElementType().getTypePtr(); 7230 Target = cast<ComplexType>(Target)->getElementType().getTypePtr(); 7231 } 7232 7233 const BuiltinType *SourceBT = dyn_cast<BuiltinType>(Source); 7234 const BuiltinType *TargetBT = dyn_cast<BuiltinType>(Target); 7235 7236 // If the source is floating point... 7237 if (SourceBT && SourceBT->isFloatingPoint()) { 7238 // ...and the target is floating point... 7239 if (TargetBT && TargetBT->isFloatingPoint()) { 7240 // ...then warn if we're dropping FP rank. 7241 7242 // Builtin FP kinds are ordered by increasing FP rank. 7243 if (SourceBT->getKind() > TargetBT->getKind()) { 7244 // Don't warn about float constants that are precisely 7245 // representable in the target type. 7246 Expr::EvalResult result; 7247 if (E->EvaluateAsRValue(result, S.Context)) { 7248 // Value might be a float, a float vector, or a float complex. 7249 if (IsSameFloatAfterCast(result.Val, 7250 S.Context.getFloatTypeSemantics(QualType(TargetBT, 0)), 7251 S.Context.getFloatTypeSemantics(QualType(SourceBT, 0)))) 7252 return; 7253 } 7254 7255 if (S.SourceMgr.isInSystemMacro(CC)) 7256 return; 7257 7258 DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_float_precision); 7259 7260 } 7261 // ... or possibly if we're increasing rank, too 7262 else if (TargetBT->getKind() > SourceBT->getKind()) { 7263 if (S.SourceMgr.isInSystemMacro(CC)) 7264 return; 7265 7266 DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_double_promotion); 7267 } 7268 return; 7269 } 7270 7271 // If the target is integral, always warn. 7272 if (TargetBT && TargetBT->isInteger()) { 7273 if (S.SourceMgr.isInSystemMacro(CC)) 7274 return; 7275 7276 Expr *InnerE = E->IgnoreParenImpCasts(); 7277 // We also want to warn on, e.g., "int i = -1.234" 7278 if (UnaryOperator *UOp = dyn_cast<UnaryOperator>(InnerE)) 7279 if (UOp->getOpcode() == UO_Minus || UOp->getOpcode() == UO_Plus) 7280 InnerE = UOp->getSubExpr()->IgnoreParenImpCasts(); 7281 7282 if (FloatingLiteral *FL = dyn_cast<FloatingLiteral>(InnerE)) { 7283 DiagnoseFloatingLiteralImpCast(S, FL, T, CC); 7284 } else { 7285 DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_float_integer); 7286 } 7287 } 7288 7289 // If the target is bool, warn if expr is a function or method call. 7290 if (Target->isSpecificBuiltinType(BuiltinType::Bool) && 7291 isa<CallExpr>(E)) { 7292 // Check last argument of function call to see if it is an 7293 // implicit cast from a type matching the type the result 7294 // is being cast to. 7295 CallExpr *CEx = cast<CallExpr>(E); 7296 unsigned NumArgs = CEx->getNumArgs(); 7297 if (NumArgs > 0) { 7298 Expr *LastA = CEx->getArg(NumArgs - 1); 7299 Expr *InnerE = LastA->IgnoreParenImpCasts(); 7300 const Type *InnerType = 7301 S.Context.getCanonicalType(InnerE->getType()).getTypePtr(); 7302 if (isa<ImplicitCastExpr>(LastA) && (InnerType == Target)) { 7303 // Warn on this floating-point to bool conversion 7304 DiagnoseImpCast(S, E, T, CC, 7305 diag::warn_impcast_floating_point_to_bool); 7306 } 7307 } 7308 } 7309 return; 7310 } 7311 7312 DiagnoseNullConversion(S, E, T, CC); 7313 7314 if (!Source->isIntegerType() || !Target->isIntegerType()) 7315 return; 7316 7317 // TODO: remove this early return once the false positives for constant->bool 7318 // in templates, macros, etc, are reduced or removed. 7319 if (Target->isSpecificBuiltinType(BuiltinType::Bool)) 7320 return; 7321 7322 IntRange SourceRange = GetExprRange(S.Context, E); 7323 IntRange TargetRange = IntRange::forTargetOfCanonicalType(S.Context, Target); 7324 7325 if (SourceRange.Width > TargetRange.Width) { 7326 // If the source is a constant, use a default-on diagnostic. 7327 // TODO: this should happen for bitfield stores, too. 7328 llvm::APSInt Value(32); 7329 if (E->isIntegerConstantExpr(Value, S.Context)) { 7330 if (S.SourceMgr.isInSystemMacro(CC)) 7331 return; 7332 7333 std::string PrettySourceValue = Value.toString(10); 7334 std::string PrettyTargetValue = PrettyPrintInRange(Value, TargetRange); 7335 7336 S.DiagRuntimeBehavior(E->getExprLoc(), E, 7337 S.PDiag(diag::warn_impcast_integer_precision_constant) 7338 << PrettySourceValue << PrettyTargetValue 7339 << E->getType() << T << E->getSourceRange() 7340 << clang::SourceRange(CC)); 7341 return; 7342 } 7343 7344 // People want to build with -Wshorten-64-to-32 and not -Wconversion. 7345 if (S.SourceMgr.isInSystemMacro(CC)) 7346 return; 7347 7348 if (TargetRange.Width == 32 && S.Context.getIntWidth(E->getType()) == 64) 7349 return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_integer_64_32, 7350 /* pruneControlFlow */ true); 7351 return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_integer_precision); 7352 } 7353 7354 if ((TargetRange.NonNegative && !SourceRange.NonNegative) || 7355 (!TargetRange.NonNegative && SourceRange.NonNegative && 7356 SourceRange.Width == TargetRange.Width)) { 7357 7358 if (S.SourceMgr.isInSystemMacro(CC)) 7359 return; 7360 7361 unsigned DiagID = diag::warn_impcast_integer_sign; 7362 7363 // Traditionally, gcc has warned about this under -Wsign-compare. 7364 // We also want to warn about it in -Wconversion. 7365 // So if -Wconversion is off, use a completely identical diagnostic 7366 // in the sign-compare group. 7367 // The conditional-checking code will 7368 if (ICContext) { 7369 DiagID = diag::warn_impcast_integer_sign_conditional; 7370 *ICContext = true; 7371 } 7372 7373 return DiagnoseImpCast(S, E, T, CC, DiagID); 7374 } 7375 7376 // Diagnose conversions between different enumeration types. 7377 // In C, we pretend that the type of an EnumConstantDecl is its enumeration 7378 // type, to give us better diagnostics. 7379 QualType SourceType = E->getType(); 7380 if (!S.getLangOpts().CPlusPlus) { 7381 if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) 7382 if (EnumConstantDecl *ECD = dyn_cast<EnumConstantDecl>(DRE->getDecl())) { 7383 EnumDecl *Enum = cast<EnumDecl>(ECD->getDeclContext()); 7384 SourceType = S.Context.getTypeDeclType(Enum); 7385 Source = S.Context.getCanonicalType(SourceType).getTypePtr(); 7386 } 7387 } 7388 7389 if (const EnumType *SourceEnum = Source->getAs<EnumType>()) 7390 if (const EnumType *TargetEnum = Target->getAs<EnumType>()) 7391 if (SourceEnum->getDecl()->hasNameForLinkage() && 7392 TargetEnum->getDecl()->hasNameForLinkage() && 7393 SourceEnum != TargetEnum) { 7394 if (S.SourceMgr.isInSystemMacro(CC)) 7395 return; 7396 7397 return DiagnoseImpCast(S, E, SourceType, T, CC, 7398 diag::warn_impcast_different_enum_types); 7399 } 7400 7401 return; 7402 } 7403 7404 void CheckConditionalOperator(Sema &S, ConditionalOperator *E, 7405 SourceLocation CC, QualType T); 7406 7407 void CheckConditionalOperand(Sema &S, Expr *E, QualType T, 7408 SourceLocation CC, bool &ICContext) { 7409 E = E->IgnoreParenImpCasts(); 7410 7411 if (isa<ConditionalOperator>(E)) 7412 return CheckConditionalOperator(S, cast<ConditionalOperator>(E), CC, T); 7413 7414 AnalyzeImplicitConversions(S, E, CC); 7415 if (E->getType() != T) 7416 return CheckImplicitConversion(S, E, T, CC, &ICContext); 7417 return; 7418 } 7419 7420 void CheckConditionalOperator(Sema &S, ConditionalOperator *E, 7421 SourceLocation CC, QualType T) { 7422 AnalyzeImplicitConversions(S, E->getCond(), E->getQuestionLoc()); 7423 7424 bool Suspicious = false; 7425 CheckConditionalOperand(S, E->getTrueExpr(), T, CC, Suspicious); 7426 CheckConditionalOperand(S, E->getFalseExpr(), T, CC, Suspicious); 7427 7428 // If -Wconversion would have warned about either of the candidates 7429 // for a signedness conversion to the context type... 7430 if (!Suspicious) return; 7431 7432 // ...but it's currently ignored... 7433 if (!S.Diags.isIgnored(diag::warn_impcast_integer_sign_conditional, CC)) 7434 return; 7435 7436 // ...then check whether it would have warned about either of the 7437 // candidates for a signedness conversion to the condition type. 7438 if (E->getType() == T) return; 7439 7440 Suspicious = false; 7441 CheckImplicitConversion(S, E->getTrueExpr()->IgnoreParenImpCasts(), 7442 E->getType(), CC, &Suspicious); 7443 if (!Suspicious) 7444 CheckImplicitConversion(S, E->getFalseExpr()->IgnoreParenImpCasts(), 7445 E->getType(), CC, &Suspicious); 7446 } 7447 7448 /// CheckBoolLikeConversion - Check conversion of given expression to boolean. 7449 /// Input argument E is a logical expression. 7450 static void CheckBoolLikeConversion(Sema &S, Expr *E, SourceLocation CC) { 7451 if (S.getLangOpts().Bool) 7452 return; 7453 CheckImplicitConversion(S, E->IgnoreParenImpCasts(), S.Context.BoolTy, CC); 7454 } 7455 7456 /// AnalyzeImplicitConversions - Find and report any interesting 7457 /// implicit conversions in the given expression. There are a couple 7458 /// of competing diagnostics here, -Wconversion and -Wsign-compare. 7459 void AnalyzeImplicitConversions(Sema &S, Expr *OrigE, SourceLocation CC) { 7460 QualType T = OrigE->getType(); 7461 Expr *E = OrigE->IgnoreParenImpCasts(); 7462 7463 if (E->isTypeDependent() || E->isValueDependent()) 7464 return; 7465 7466 // For conditional operators, we analyze the arguments as if they 7467 // were being fed directly into the output. 7468 if (isa<ConditionalOperator>(E)) { 7469 ConditionalOperator *CO = cast<ConditionalOperator>(E); 7470 CheckConditionalOperator(S, CO, CC, T); 7471 return; 7472 } 7473 7474 // Check implicit argument conversions for function calls. 7475 if (CallExpr *Call = dyn_cast<CallExpr>(E)) 7476 CheckImplicitArgumentConversions(S, Call, CC); 7477 7478 // Go ahead and check any implicit conversions we might have skipped. 7479 // The non-canonical typecheck is just an optimization; 7480 // CheckImplicitConversion will filter out dead implicit conversions. 7481 if (E->getType() != T) 7482 CheckImplicitConversion(S, E, T, CC); 7483 7484 // Now continue drilling into this expression. 7485 7486 if (PseudoObjectExpr * POE = dyn_cast<PseudoObjectExpr>(E)) { 7487 if (POE->getResultExpr()) 7488 E = POE->getResultExpr(); 7489 } 7490 7491 if (const OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(E)) { 7492 if (OVE->getSourceExpr()) 7493 AnalyzeImplicitConversions(S, OVE->getSourceExpr(), CC); 7494 return; 7495 } 7496 7497 // Skip past explicit casts. 7498 if (isa<ExplicitCastExpr>(E)) { 7499 E = cast<ExplicitCastExpr>(E)->getSubExpr()->IgnoreParenImpCasts(); 7500 return AnalyzeImplicitConversions(S, E, CC); 7501 } 7502 7503 if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) { 7504 // Do a somewhat different check with comparison operators. 7505 if (BO->isComparisonOp()) 7506 return AnalyzeComparison(S, BO); 7507 7508 // And with simple assignments. 7509 if (BO->getOpcode() == BO_Assign) 7510 return AnalyzeAssignment(S, BO); 7511 } 7512 7513 // These break the otherwise-useful invariant below. Fortunately, 7514 // we don't really need to recurse into them, because any internal 7515 // expressions should have been analyzed already when they were 7516 // built into statements. 7517 if (isa<StmtExpr>(E)) return; 7518 7519 // Don't descend into unevaluated contexts. 7520 if (isa<UnaryExprOrTypeTraitExpr>(E)) return; 7521 7522 // Now just recurse over the expression's children. 7523 CC = E->getExprLoc(); 7524 BinaryOperator *BO = dyn_cast<BinaryOperator>(E); 7525 bool IsLogicalAndOperator = BO && BO->getOpcode() == BO_LAnd; 7526 for (Stmt *SubStmt : E->children()) { 7527 Expr *ChildExpr = dyn_cast_or_null<Expr>(SubStmt); 7528 if (!ChildExpr) 7529 continue; 7530 7531 if (IsLogicalAndOperator && 7532 isa<StringLiteral>(ChildExpr->IgnoreParenImpCasts())) 7533 // Ignore checking string literals that are in logical and operators. 7534 // This is a common pattern for asserts. 7535 continue; 7536 AnalyzeImplicitConversions(S, ChildExpr, CC); 7537 } 7538 7539 if (BO && BO->isLogicalOp()) { 7540 Expr *SubExpr = BO->getLHS()->IgnoreParenImpCasts(); 7541 if (!IsLogicalAndOperator || !isa<StringLiteral>(SubExpr)) 7542 ::CheckBoolLikeConversion(S, SubExpr, BO->getExprLoc()); 7543 7544 SubExpr = BO->getRHS()->IgnoreParenImpCasts(); 7545 if (!IsLogicalAndOperator || !isa<StringLiteral>(SubExpr)) 7546 ::CheckBoolLikeConversion(S, SubExpr, BO->getExprLoc()); 7547 } 7548 7549 if (const UnaryOperator *U = dyn_cast<UnaryOperator>(E)) 7550 if (U->getOpcode() == UO_LNot) 7551 ::CheckBoolLikeConversion(S, U->getSubExpr(), CC); 7552 } 7553 7554 } // end anonymous namespace 7555 7556 enum { 7557 AddressOf, 7558 FunctionPointer, 7559 ArrayPointer 7560 }; 7561 7562 // Helper function for Sema::DiagnoseAlwaysNonNullPointer. 7563 // Returns true when emitting a warning about taking the address of a reference. 7564 static bool CheckForReference(Sema &SemaRef, const Expr *E, 7565 PartialDiagnostic PD) { 7566 E = E->IgnoreParenImpCasts(); 7567 7568 const FunctionDecl *FD = nullptr; 7569 7570 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) { 7571 if (!DRE->getDecl()->getType()->isReferenceType()) 7572 return false; 7573 } else if (const MemberExpr *M = dyn_cast<MemberExpr>(E)) { 7574 if (!M->getMemberDecl()->getType()->isReferenceType()) 7575 return false; 7576 } else if (const CallExpr *Call = dyn_cast<CallExpr>(E)) { 7577 if (!Call->getCallReturnType(SemaRef.Context)->isReferenceType()) 7578 return false; 7579 FD = Call->getDirectCallee(); 7580 } else { 7581 return false; 7582 } 7583 7584 SemaRef.Diag(E->getExprLoc(), PD); 7585 7586 // If possible, point to location of function. 7587 if (FD) { 7588 SemaRef.Diag(FD->getLocation(), diag::note_reference_is_return_value) << FD; 7589 } 7590 7591 return true; 7592 } 7593 7594 // Returns true if the SourceLocation is expanded from any macro body. 7595 // Returns false if the SourceLocation is invalid, is from not in a macro 7596 // expansion, or is from expanded from a top-level macro argument. 7597 static bool IsInAnyMacroBody(const SourceManager &SM, SourceLocation Loc) { 7598 if (Loc.isInvalid()) 7599 return false; 7600 7601 while (Loc.isMacroID()) { 7602 if (SM.isMacroBodyExpansion(Loc)) 7603 return true; 7604 Loc = SM.getImmediateMacroCallerLoc(Loc); 7605 } 7606 7607 return false; 7608 } 7609 7610 /// \brief Diagnose pointers that are always non-null. 7611 /// \param E the expression containing the pointer 7612 /// \param NullKind NPCK_NotNull if E is a cast to bool, otherwise, E is 7613 /// compared to a null pointer 7614 /// \param IsEqual True when the comparison is equal to a null pointer 7615 /// \param Range Extra SourceRange to highlight in the diagnostic 7616 void Sema::DiagnoseAlwaysNonNullPointer(Expr *E, 7617 Expr::NullPointerConstantKind NullKind, 7618 bool IsEqual, SourceRange Range) { 7619 if (!E) 7620 return; 7621 7622 // Don't warn inside macros. 7623 if (E->getExprLoc().isMacroID()) { 7624 const SourceManager &SM = getSourceManager(); 7625 if (IsInAnyMacroBody(SM, E->getExprLoc()) || 7626 IsInAnyMacroBody(SM, Range.getBegin())) 7627 return; 7628 } 7629 E = E->IgnoreImpCasts(); 7630 7631 const bool IsCompare = NullKind != Expr::NPCK_NotNull; 7632 7633 if (isa<CXXThisExpr>(E)) { 7634 unsigned DiagID = IsCompare ? diag::warn_this_null_compare 7635 : diag::warn_this_bool_conversion; 7636 Diag(E->getExprLoc(), DiagID) << E->getSourceRange() << Range << IsEqual; 7637 return; 7638 } 7639 7640 bool IsAddressOf = false; 7641 7642 if (UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) { 7643 if (UO->getOpcode() != UO_AddrOf) 7644 return; 7645 IsAddressOf = true; 7646 E = UO->getSubExpr(); 7647 } 7648 7649 if (IsAddressOf) { 7650 unsigned DiagID = IsCompare 7651 ? diag::warn_address_of_reference_null_compare 7652 : diag::warn_address_of_reference_bool_conversion; 7653 PartialDiagnostic PD = PDiag(DiagID) << E->getSourceRange() << Range 7654 << IsEqual; 7655 if (CheckForReference(*this, E, PD)) { 7656 return; 7657 } 7658 } 7659 7660 // Expect to find a single Decl. Skip anything more complicated. 7661 ValueDecl *D = nullptr; 7662 if (DeclRefExpr *R = dyn_cast<DeclRefExpr>(E)) { 7663 D = R->getDecl(); 7664 } else if (MemberExpr *M = dyn_cast<MemberExpr>(E)) { 7665 D = M->getMemberDecl(); 7666 } 7667 7668 // Weak Decls can be null. 7669 if (!D || D->isWeak()) 7670 return; 7671 7672 // Check for parameter decl with nonnull attribute 7673 if (const ParmVarDecl* PV = dyn_cast<ParmVarDecl>(D)) { 7674 if (getCurFunction() && !getCurFunction()->ModifiedNonNullParams.count(PV)) 7675 if (const FunctionDecl* FD = dyn_cast<FunctionDecl>(PV->getDeclContext())) { 7676 unsigned NumArgs = FD->getNumParams(); 7677 llvm::SmallBitVector AttrNonNull(NumArgs); 7678 for (const auto *NonNull : FD->specific_attrs<NonNullAttr>()) { 7679 if (!NonNull->args_size()) { 7680 AttrNonNull.set(0, NumArgs); 7681 break; 7682 } 7683 for (unsigned Val : NonNull->args()) { 7684 if (Val >= NumArgs) 7685 continue; 7686 AttrNonNull.set(Val); 7687 } 7688 } 7689 if (!AttrNonNull.empty()) 7690 for (unsigned i = 0; i < NumArgs; ++i) 7691 if (FD->getParamDecl(i) == PV && 7692 (AttrNonNull[i] || PV->hasAttr<NonNullAttr>())) { 7693 std::string Str; 7694 llvm::raw_string_ostream S(Str); 7695 E->printPretty(S, nullptr, getPrintingPolicy()); 7696 unsigned DiagID = IsCompare ? diag::warn_nonnull_parameter_compare 7697 : diag::warn_cast_nonnull_to_bool; 7698 Diag(E->getExprLoc(), DiagID) << S.str() << E->getSourceRange() 7699 << Range << IsEqual; 7700 return; 7701 } 7702 } 7703 } 7704 7705 QualType T = D->getType(); 7706 const bool IsArray = T->isArrayType(); 7707 const bool IsFunction = T->isFunctionType(); 7708 7709 // Address of function is used to silence the function warning. 7710 if (IsAddressOf && IsFunction) { 7711 return; 7712 } 7713 7714 // Found nothing. 7715 if (!IsAddressOf && !IsFunction && !IsArray) 7716 return; 7717 7718 // Pretty print the expression for the diagnostic. 7719 std::string Str; 7720 llvm::raw_string_ostream S(Str); 7721 E->printPretty(S, nullptr, getPrintingPolicy()); 7722 7723 unsigned DiagID = IsCompare ? diag::warn_null_pointer_compare 7724 : diag::warn_impcast_pointer_to_bool; 7725 unsigned DiagType; 7726 if (IsAddressOf) 7727 DiagType = AddressOf; 7728 else if (IsFunction) 7729 DiagType = FunctionPointer; 7730 else if (IsArray) 7731 DiagType = ArrayPointer; 7732 else 7733 llvm_unreachable("Could not determine diagnostic."); 7734 Diag(E->getExprLoc(), DiagID) << DiagType << S.str() << E->getSourceRange() 7735 << Range << IsEqual; 7736 7737 if (!IsFunction) 7738 return; 7739 7740 // Suggest '&' to silence the function warning. 7741 Diag(E->getExprLoc(), diag::note_function_warning_silence) 7742 << FixItHint::CreateInsertion(E->getLocStart(), "&"); 7743 7744 // Check to see if '()' fixit should be emitted. 7745 QualType ReturnType; 7746 UnresolvedSet<4> NonTemplateOverloads; 7747 tryExprAsCall(*E, ReturnType, NonTemplateOverloads); 7748 if (ReturnType.isNull()) 7749 return; 7750 7751 if (IsCompare) { 7752 // There are two cases here. If there is null constant, the only suggest 7753 // for a pointer return type. If the null is 0, then suggest if the return 7754 // type is a pointer or an integer type. 7755 if (!ReturnType->isPointerType()) { 7756 if (NullKind == Expr::NPCK_ZeroExpression || 7757 NullKind == Expr::NPCK_ZeroLiteral) { 7758 if (!ReturnType->isIntegerType()) 7759 return; 7760 } else { 7761 return; 7762 } 7763 } 7764 } else { // !IsCompare 7765 // For function to bool, only suggest if the function pointer has bool 7766 // return type. 7767 if (!ReturnType->isSpecificBuiltinType(BuiltinType::Bool)) 7768 return; 7769 } 7770 Diag(E->getExprLoc(), diag::note_function_to_function_call) 7771 << FixItHint::CreateInsertion(getLocForEndOfToken(E->getLocEnd()), "()"); 7772 } 7773 7774 7775 /// Diagnoses "dangerous" implicit conversions within the given 7776 /// expression (which is a full expression). Implements -Wconversion 7777 /// and -Wsign-compare. 7778 /// 7779 /// \param CC the "context" location of the implicit conversion, i.e. 7780 /// the most location of the syntactic entity requiring the implicit 7781 /// conversion 7782 void Sema::CheckImplicitConversions(Expr *E, SourceLocation CC) { 7783 // Don't diagnose in unevaluated contexts. 7784 if (isUnevaluatedContext()) 7785 return; 7786 7787 // Don't diagnose for value- or type-dependent expressions. 7788 if (E->isTypeDependent() || E->isValueDependent()) 7789 return; 7790 7791 // Check for array bounds violations in cases where the check isn't triggered 7792 // elsewhere for other Expr types (like BinaryOperators), e.g. when an 7793 // ArraySubscriptExpr is on the RHS of a variable initialization. 7794 CheckArrayAccess(E); 7795 7796 // This is not the right CC for (e.g.) a variable initialization. 7797 AnalyzeImplicitConversions(*this, E, CC); 7798 } 7799 7800 /// CheckBoolLikeConversion - Check conversion of given expression to boolean. 7801 /// Input argument E is a logical expression. 7802 void Sema::CheckBoolLikeConversion(Expr *E, SourceLocation CC) { 7803 ::CheckBoolLikeConversion(*this, E, CC); 7804 } 7805 7806 /// Diagnose when expression is an integer constant expression and its evaluation 7807 /// results in integer overflow 7808 void Sema::CheckForIntOverflow (Expr *E) { 7809 if (isa<BinaryOperator>(E->IgnoreParenCasts())) 7810 E->IgnoreParenCasts()->EvaluateForOverflow(Context); 7811 } 7812 7813 namespace { 7814 /// \brief Visitor for expressions which looks for unsequenced operations on the 7815 /// same object. 7816 class SequenceChecker : public EvaluatedExprVisitor<SequenceChecker> { 7817 typedef EvaluatedExprVisitor<SequenceChecker> Base; 7818 7819 /// \brief A tree of sequenced regions within an expression. Two regions are 7820 /// unsequenced if one is an ancestor or a descendent of the other. When we 7821 /// finish processing an expression with sequencing, such as a comma 7822 /// expression, we fold its tree nodes into its parent, since they are 7823 /// unsequenced with respect to nodes we will visit later. 7824 class SequenceTree { 7825 struct Value { 7826 explicit Value(unsigned Parent) : Parent(Parent), Merged(false) {} 7827 unsigned Parent : 31; 7828 bool Merged : 1; 7829 }; 7830 SmallVector<Value, 8> Values; 7831 7832 public: 7833 /// \brief A region within an expression which may be sequenced with respect 7834 /// to some other region. 7835 class Seq { 7836 explicit Seq(unsigned N) : Index(N) {} 7837 unsigned Index; 7838 friend class SequenceTree; 7839 public: 7840 Seq() : Index(0) {} 7841 }; 7842 7843 SequenceTree() { Values.push_back(Value(0)); } 7844 Seq root() const { return Seq(0); } 7845 7846 /// \brief Create a new sequence of operations, which is an unsequenced 7847 /// subset of \p Parent. This sequence of operations is sequenced with 7848 /// respect to other children of \p Parent. 7849 Seq allocate(Seq Parent) { 7850 Values.push_back(Value(Parent.Index)); 7851 return Seq(Values.size() - 1); 7852 } 7853 7854 /// \brief Merge a sequence of operations into its parent. 7855 void merge(Seq S) { 7856 Values[S.Index].Merged = true; 7857 } 7858 7859 /// \brief Determine whether two operations are unsequenced. This operation 7860 /// is asymmetric: \p Cur should be the more recent sequence, and \p Old 7861 /// should have been merged into its parent as appropriate. 7862 bool isUnsequenced(Seq Cur, Seq Old) { 7863 unsigned C = representative(Cur.Index); 7864 unsigned Target = representative(Old.Index); 7865 while (C >= Target) { 7866 if (C == Target) 7867 return true; 7868 C = Values[C].Parent; 7869 } 7870 return false; 7871 } 7872 7873 private: 7874 /// \brief Pick a representative for a sequence. 7875 unsigned representative(unsigned K) { 7876 if (Values[K].Merged) 7877 // Perform path compression as we go. 7878 return Values[K].Parent = representative(Values[K].Parent); 7879 return K; 7880 } 7881 }; 7882 7883 /// An object for which we can track unsequenced uses. 7884 typedef NamedDecl *Object; 7885 7886 /// Different flavors of object usage which we track. We only track the 7887 /// least-sequenced usage of each kind. 7888 enum UsageKind { 7889 /// A read of an object. Multiple unsequenced reads are OK. 7890 UK_Use, 7891 /// A modification of an object which is sequenced before the value 7892 /// computation of the expression, such as ++n in C++. 7893 UK_ModAsValue, 7894 /// A modification of an object which is not sequenced before the value 7895 /// computation of the expression, such as n++. 7896 UK_ModAsSideEffect, 7897 7898 UK_Count = UK_ModAsSideEffect + 1 7899 }; 7900 7901 struct Usage { 7902 Usage() : Use(nullptr), Seq() {} 7903 Expr *Use; 7904 SequenceTree::Seq Seq; 7905 }; 7906 7907 struct UsageInfo { 7908 UsageInfo() : Diagnosed(false) {} 7909 Usage Uses[UK_Count]; 7910 /// Have we issued a diagnostic for this variable already? 7911 bool Diagnosed; 7912 }; 7913 typedef llvm::SmallDenseMap<Object, UsageInfo, 16> UsageInfoMap; 7914 7915 Sema &SemaRef; 7916 /// Sequenced regions within the expression. 7917 SequenceTree Tree; 7918 /// Declaration modifications and references which we have seen. 7919 UsageInfoMap UsageMap; 7920 /// The region we are currently within. 7921 SequenceTree::Seq Region; 7922 /// Filled in with declarations which were modified as a side-effect 7923 /// (that is, post-increment operations). 7924 SmallVectorImpl<std::pair<Object, Usage> > *ModAsSideEffect; 7925 /// Expressions to check later. We defer checking these to reduce 7926 /// stack usage. 7927 SmallVectorImpl<Expr *> &WorkList; 7928 7929 /// RAII object wrapping the visitation of a sequenced subexpression of an 7930 /// expression. At the end of this process, the side-effects of the evaluation 7931 /// become sequenced with respect to the value computation of the result, so 7932 /// we downgrade any UK_ModAsSideEffect within the evaluation to 7933 /// UK_ModAsValue. 7934 struct SequencedSubexpression { 7935 SequencedSubexpression(SequenceChecker &Self) 7936 : Self(Self), OldModAsSideEffect(Self.ModAsSideEffect) { 7937 Self.ModAsSideEffect = &ModAsSideEffect; 7938 } 7939 ~SequencedSubexpression() { 7940 for (auto MI = ModAsSideEffect.rbegin(), ME = ModAsSideEffect.rend(); 7941 MI != ME; ++MI) { 7942 UsageInfo &U = Self.UsageMap[MI->first]; 7943 auto &SideEffectUsage = U.Uses[UK_ModAsSideEffect]; 7944 Self.addUsage(U, MI->first, SideEffectUsage.Use, UK_ModAsValue); 7945 SideEffectUsage = MI->second; 7946 } 7947 Self.ModAsSideEffect = OldModAsSideEffect; 7948 } 7949 7950 SequenceChecker &Self; 7951 SmallVector<std::pair<Object, Usage>, 4> ModAsSideEffect; 7952 SmallVectorImpl<std::pair<Object, Usage> > *OldModAsSideEffect; 7953 }; 7954 7955 /// RAII object wrapping the visitation of a subexpression which we might 7956 /// choose to evaluate as a constant. If any subexpression is evaluated and 7957 /// found to be non-constant, this allows us to suppress the evaluation of 7958 /// the outer expression. 7959 class EvaluationTracker { 7960 public: 7961 EvaluationTracker(SequenceChecker &Self) 7962 : Self(Self), Prev(Self.EvalTracker), EvalOK(true) { 7963 Self.EvalTracker = this; 7964 } 7965 ~EvaluationTracker() { 7966 Self.EvalTracker = Prev; 7967 if (Prev) 7968 Prev->EvalOK &= EvalOK; 7969 } 7970 7971 bool evaluate(const Expr *E, bool &Result) { 7972 if (!EvalOK || E->isValueDependent()) 7973 return false; 7974 EvalOK = E->EvaluateAsBooleanCondition(Result, Self.SemaRef.Context); 7975 return EvalOK; 7976 } 7977 7978 private: 7979 SequenceChecker &Self; 7980 EvaluationTracker *Prev; 7981 bool EvalOK; 7982 } *EvalTracker; 7983 7984 /// \brief Find the object which is produced by the specified expression, 7985 /// if any. 7986 Object getObject(Expr *E, bool Mod) const { 7987 E = E->IgnoreParenCasts(); 7988 if (UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) { 7989 if (Mod && (UO->getOpcode() == UO_PreInc || UO->getOpcode() == UO_PreDec)) 7990 return getObject(UO->getSubExpr(), Mod); 7991 } else if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) { 7992 if (BO->getOpcode() == BO_Comma) 7993 return getObject(BO->getRHS(), Mod); 7994 if (Mod && BO->isAssignmentOp()) 7995 return getObject(BO->getLHS(), Mod); 7996 } else if (MemberExpr *ME = dyn_cast<MemberExpr>(E)) { 7997 // FIXME: Check for more interesting cases, like "x.n = ++x.n". 7998 if (isa<CXXThisExpr>(ME->getBase()->IgnoreParenCasts())) 7999 return ME->getMemberDecl(); 8000 } else if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) 8001 // FIXME: If this is a reference, map through to its value. 8002 return DRE->getDecl(); 8003 return nullptr; 8004 } 8005 8006 /// \brief Note that an object was modified or used by an expression. 8007 void addUsage(UsageInfo &UI, Object O, Expr *Ref, UsageKind UK) { 8008 Usage &U = UI.Uses[UK]; 8009 if (!U.Use || !Tree.isUnsequenced(Region, U.Seq)) { 8010 if (UK == UK_ModAsSideEffect && ModAsSideEffect) 8011 ModAsSideEffect->push_back(std::make_pair(O, U)); 8012 U.Use = Ref; 8013 U.Seq = Region; 8014 } 8015 } 8016 /// \brief Check whether a modification or use conflicts with a prior usage. 8017 void checkUsage(Object O, UsageInfo &UI, Expr *Ref, UsageKind OtherKind, 8018 bool IsModMod) { 8019 if (UI.Diagnosed) 8020 return; 8021 8022 const Usage &U = UI.Uses[OtherKind]; 8023 if (!U.Use || !Tree.isUnsequenced(Region, U.Seq)) 8024 return; 8025 8026 Expr *Mod = U.Use; 8027 Expr *ModOrUse = Ref; 8028 if (OtherKind == UK_Use) 8029 std::swap(Mod, ModOrUse); 8030 8031 SemaRef.Diag(Mod->getExprLoc(), 8032 IsModMod ? diag::warn_unsequenced_mod_mod 8033 : diag::warn_unsequenced_mod_use) 8034 << O << SourceRange(ModOrUse->getExprLoc()); 8035 UI.Diagnosed = true; 8036 } 8037 8038 void notePreUse(Object O, Expr *Use) { 8039 UsageInfo &U = UsageMap[O]; 8040 // Uses conflict with other modifications. 8041 checkUsage(O, U, Use, UK_ModAsValue, false); 8042 } 8043 void notePostUse(Object O, Expr *Use) { 8044 UsageInfo &U = UsageMap[O]; 8045 checkUsage(O, U, Use, UK_ModAsSideEffect, false); 8046 addUsage(U, O, Use, UK_Use); 8047 } 8048 8049 void notePreMod(Object O, Expr *Mod) { 8050 UsageInfo &U = UsageMap[O]; 8051 // Modifications conflict with other modifications and with uses. 8052 checkUsage(O, U, Mod, UK_ModAsValue, true); 8053 checkUsage(O, U, Mod, UK_Use, false); 8054 } 8055 void notePostMod(Object O, Expr *Use, UsageKind UK) { 8056 UsageInfo &U = UsageMap[O]; 8057 checkUsage(O, U, Use, UK_ModAsSideEffect, true); 8058 addUsage(U, O, Use, UK); 8059 } 8060 8061 public: 8062 SequenceChecker(Sema &S, Expr *E, SmallVectorImpl<Expr *> &WorkList) 8063 : Base(S.Context), SemaRef(S), Region(Tree.root()), 8064 ModAsSideEffect(nullptr), WorkList(WorkList), EvalTracker(nullptr) { 8065 Visit(E); 8066 } 8067 8068 void VisitStmt(Stmt *S) { 8069 // Skip all statements which aren't expressions for now. 8070 } 8071 8072 void VisitExpr(Expr *E) { 8073 // By default, just recurse to evaluated subexpressions. 8074 Base::VisitStmt(E); 8075 } 8076 8077 void VisitCastExpr(CastExpr *E) { 8078 Object O = Object(); 8079 if (E->getCastKind() == CK_LValueToRValue) 8080 O = getObject(E->getSubExpr(), false); 8081 8082 if (O) 8083 notePreUse(O, E); 8084 VisitExpr(E); 8085 if (O) 8086 notePostUse(O, E); 8087 } 8088 8089 void VisitBinComma(BinaryOperator *BO) { 8090 // C++11 [expr.comma]p1: 8091 // Every value computation and side effect associated with the left 8092 // expression is sequenced before every value computation and side 8093 // effect associated with the right expression. 8094 SequenceTree::Seq LHS = Tree.allocate(Region); 8095 SequenceTree::Seq RHS = Tree.allocate(Region); 8096 SequenceTree::Seq OldRegion = Region; 8097 8098 { 8099 SequencedSubexpression SeqLHS(*this); 8100 Region = LHS; 8101 Visit(BO->getLHS()); 8102 } 8103 8104 Region = RHS; 8105 Visit(BO->getRHS()); 8106 8107 Region = OldRegion; 8108 8109 // Forget that LHS and RHS are sequenced. They are both unsequenced 8110 // with respect to other stuff. 8111 Tree.merge(LHS); 8112 Tree.merge(RHS); 8113 } 8114 8115 void VisitBinAssign(BinaryOperator *BO) { 8116 // The modification is sequenced after the value computation of the LHS 8117 // and RHS, so check it before inspecting the operands and update the 8118 // map afterwards. 8119 Object O = getObject(BO->getLHS(), true); 8120 if (!O) 8121 return VisitExpr(BO); 8122 8123 notePreMod(O, BO); 8124 8125 // C++11 [expr.ass]p7: 8126 // E1 op= E2 is equivalent to E1 = E1 op E2, except that E1 is evaluated 8127 // only once. 8128 // 8129 // Therefore, for a compound assignment operator, O is considered used 8130 // everywhere except within the evaluation of E1 itself. 8131 if (isa<CompoundAssignOperator>(BO)) 8132 notePreUse(O, BO); 8133 8134 Visit(BO->getLHS()); 8135 8136 if (isa<CompoundAssignOperator>(BO)) 8137 notePostUse(O, BO); 8138 8139 Visit(BO->getRHS()); 8140 8141 // C++11 [expr.ass]p1: 8142 // the assignment is sequenced [...] before the value computation of the 8143 // assignment expression. 8144 // C11 6.5.16/3 has no such rule. 8145 notePostMod(O, BO, SemaRef.getLangOpts().CPlusPlus ? UK_ModAsValue 8146 : UK_ModAsSideEffect); 8147 } 8148 void VisitCompoundAssignOperator(CompoundAssignOperator *CAO) { 8149 VisitBinAssign(CAO); 8150 } 8151 8152 void VisitUnaryPreInc(UnaryOperator *UO) { VisitUnaryPreIncDec(UO); } 8153 void VisitUnaryPreDec(UnaryOperator *UO) { VisitUnaryPreIncDec(UO); } 8154 void VisitUnaryPreIncDec(UnaryOperator *UO) { 8155 Object O = getObject(UO->getSubExpr(), true); 8156 if (!O) 8157 return VisitExpr(UO); 8158 8159 notePreMod(O, UO); 8160 Visit(UO->getSubExpr()); 8161 // C++11 [expr.pre.incr]p1: 8162 // the expression ++x is equivalent to x+=1 8163 notePostMod(O, UO, SemaRef.getLangOpts().CPlusPlus ? UK_ModAsValue 8164 : UK_ModAsSideEffect); 8165 } 8166 8167 void VisitUnaryPostInc(UnaryOperator *UO) { VisitUnaryPostIncDec(UO); } 8168 void VisitUnaryPostDec(UnaryOperator *UO) { VisitUnaryPostIncDec(UO); } 8169 void VisitUnaryPostIncDec(UnaryOperator *UO) { 8170 Object O = getObject(UO->getSubExpr(), true); 8171 if (!O) 8172 return VisitExpr(UO); 8173 8174 notePreMod(O, UO); 8175 Visit(UO->getSubExpr()); 8176 notePostMod(O, UO, UK_ModAsSideEffect); 8177 } 8178 8179 /// Don't visit the RHS of '&&' or '||' if it might not be evaluated. 8180 void VisitBinLOr(BinaryOperator *BO) { 8181 // The side-effects of the LHS of an '&&' are sequenced before the 8182 // value computation of the RHS, and hence before the value computation 8183 // of the '&&' itself, unless the LHS evaluates to zero. We treat them 8184 // as if they were unconditionally sequenced. 8185 EvaluationTracker Eval(*this); 8186 { 8187 SequencedSubexpression Sequenced(*this); 8188 Visit(BO->getLHS()); 8189 } 8190 8191 bool Result; 8192 if (Eval.evaluate(BO->getLHS(), Result)) { 8193 if (!Result) 8194 Visit(BO->getRHS()); 8195 } else { 8196 // Check for unsequenced operations in the RHS, treating it as an 8197 // entirely separate evaluation. 8198 // 8199 // FIXME: If there are operations in the RHS which are unsequenced 8200 // with respect to operations outside the RHS, and those operations 8201 // are unconditionally evaluated, diagnose them. 8202 WorkList.push_back(BO->getRHS()); 8203 } 8204 } 8205 void VisitBinLAnd(BinaryOperator *BO) { 8206 EvaluationTracker Eval(*this); 8207 { 8208 SequencedSubexpression Sequenced(*this); 8209 Visit(BO->getLHS()); 8210 } 8211 8212 bool Result; 8213 if (Eval.evaluate(BO->getLHS(), Result)) { 8214 if (Result) 8215 Visit(BO->getRHS()); 8216 } else { 8217 WorkList.push_back(BO->getRHS()); 8218 } 8219 } 8220 8221 // Only visit the condition, unless we can be sure which subexpression will 8222 // be chosen. 8223 void VisitAbstractConditionalOperator(AbstractConditionalOperator *CO) { 8224 EvaluationTracker Eval(*this); 8225 { 8226 SequencedSubexpression Sequenced(*this); 8227 Visit(CO->getCond()); 8228 } 8229 8230 bool Result; 8231 if (Eval.evaluate(CO->getCond(), Result)) 8232 Visit(Result ? CO->getTrueExpr() : CO->getFalseExpr()); 8233 else { 8234 WorkList.push_back(CO->getTrueExpr()); 8235 WorkList.push_back(CO->getFalseExpr()); 8236 } 8237 } 8238 8239 void VisitCallExpr(CallExpr *CE) { 8240 // C++11 [intro.execution]p15: 8241 // When calling a function [...], every value computation and side effect 8242 // associated with any argument expression, or with the postfix expression 8243 // designating the called function, is sequenced before execution of every 8244 // expression or statement in the body of the function [and thus before 8245 // the value computation of its result]. 8246 SequencedSubexpression Sequenced(*this); 8247 Base::VisitCallExpr(CE); 8248 8249 // FIXME: CXXNewExpr and CXXDeleteExpr implicitly call functions. 8250 } 8251 8252 void VisitCXXConstructExpr(CXXConstructExpr *CCE) { 8253 // This is a call, so all subexpressions are sequenced before the result. 8254 SequencedSubexpression Sequenced(*this); 8255 8256 if (!CCE->isListInitialization()) 8257 return VisitExpr(CCE); 8258 8259 // In C++11, list initializations are sequenced. 8260 SmallVector<SequenceTree::Seq, 32> Elts; 8261 SequenceTree::Seq Parent = Region; 8262 for (CXXConstructExpr::arg_iterator I = CCE->arg_begin(), 8263 E = CCE->arg_end(); 8264 I != E; ++I) { 8265 Region = Tree.allocate(Parent); 8266 Elts.push_back(Region); 8267 Visit(*I); 8268 } 8269 8270 // Forget that the initializers are sequenced. 8271 Region = Parent; 8272 for (unsigned I = 0; I < Elts.size(); ++I) 8273 Tree.merge(Elts[I]); 8274 } 8275 8276 void VisitInitListExpr(InitListExpr *ILE) { 8277 if (!SemaRef.getLangOpts().CPlusPlus11) 8278 return VisitExpr(ILE); 8279 8280 // In C++11, list initializations are sequenced. 8281 SmallVector<SequenceTree::Seq, 32> Elts; 8282 SequenceTree::Seq Parent = Region; 8283 for (unsigned I = 0; I < ILE->getNumInits(); ++I) { 8284 Expr *E = ILE->getInit(I); 8285 if (!E) continue; 8286 Region = Tree.allocate(Parent); 8287 Elts.push_back(Region); 8288 Visit(E); 8289 } 8290 8291 // Forget that the initializers are sequenced. 8292 Region = Parent; 8293 for (unsigned I = 0; I < Elts.size(); ++I) 8294 Tree.merge(Elts[I]); 8295 } 8296 }; 8297 } 8298 8299 void Sema::CheckUnsequencedOperations(Expr *E) { 8300 SmallVector<Expr *, 8> WorkList; 8301 WorkList.push_back(E); 8302 while (!WorkList.empty()) { 8303 Expr *Item = WorkList.pop_back_val(); 8304 SequenceChecker(*this, Item, WorkList); 8305 } 8306 } 8307 8308 void Sema::CheckCompletedExpr(Expr *E, SourceLocation CheckLoc, 8309 bool IsConstexpr) { 8310 CheckImplicitConversions(E, CheckLoc); 8311 CheckUnsequencedOperations(E); 8312 if (!IsConstexpr && !E->isValueDependent()) 8313 CheckForIntOverflow(E); 8314 } 8315 8316 void Sema::CheckBitFieldInitialization(SourceLocation InitLoc, 8317 FieldDecl *BitField, 8318 Expr *Init) { 8319 (void) AnalyzeBitFieldAssignment(*this, BitField, Init, InitLoc); 8320 } 8321 8322 static void diagnoseArrayStarInParamType(Sema &S, QualType PType, 8323 SourceLocation Loc) { 8324 if (!PType->isVariablyModifiedType()) 8325 return; 8326 if (const auto *PointerTy = dyn_cast<PointerType>(PType)) { 8327 diagnoseArrayStarInParamType(S, PointerTy->getPointeeType(), Loc); 8328 return; 8329 } 8330 if (const auto *ReferenceTy = dyn_cast<ReferenceType>(PType)) { 8331 diagnoseArrayStarInParamType(S, ReferenceTy->getPointeeType(), Loc); 8332 return; 8333 } 8334 if (const auto *ParenTy = dyn_cast<ParenType>(PType)) { 8335 diagnoseArrayStarInParamType(S, ParenTy->getInnerType(), Loc); 8336 return; 8337 } 8338 8339 const ArrayType *AT = S.Context.getAsArrayType(PType); 8340 if (!AT) 8341 return; 8342 8343 if (AT->getSizeModifier() != ArrayType::Star) { 8344 diagnoseArrayStarInParamType(S, AT->getElementType(), Loc); 8345 return; 8346 } 8347 8348 S.Diag(Loc, diag::err_array_star_in_function_definition); 8349 } 8350 8351 /// CheckParmsForFunctionDef - Check that the parameters of the given 8352 /// function are appropriate for the definition of a function. This 8353 /// takes care of any checks that cannot be performed on the 8354 /// declaration itself, e.g., that the types of each of the function 8355 /// parameters are complete. 8356 bool Sema::CheckParmsForFunctionDef(ParmVarDecl *const *P, 8357 ParmVarDecl *const *PEnd, 8358 bool CheckParameterNames) { 8359 bool HasInvalidParm = false; 8360 for (; P != PEnd; ++P) { 8361 ParmVarDecl *Param = *P; 8362 8363 // C99 6.7.5.3p4: the parameters in a parameter type list in a 8364 // function declarator that is part of a function definition of 8365 // that function shall not have incomplete type. 8366 // 8367 // This is also C++ [dcl.fct]p6. 8368 if (!Param->isInvalidDecl() && 8369 RequireCompleteType(Param->getLocation(), Param->getType(), 8370 diag::err_typecheck_decl_incomplete_type)) { 8371 Param->setInvalidDecl(); 8372 HasInvalidParm = true; 8373 } 8374 8375 // C99 6.9.1p5: If the declarator includes a parameter type list, the 8376 // declaration of each parameter shall include an identifier. 8377 if (CheckParameterNames && 8378 Param->getIdentifier() == nullptr && 8379 !Param->isImplicit() && 8380 !getLangOpts().CPlusPlus) 8381 Diag(Param->getLocation(), diag::err_parameter_name_omitted); 8382 8383 // C99 6.7.5.3p12: 8384 // If the function declarator is not part of a definition of that 8385 // function, parameters may have incomplete type and may use the [*] 8386 // notation in their sequences of declarator specifiers to specify 8387 // variable length array types. 8388 QualType PType = Param->getOriginalType(); 8389 // FIXME: This diagnostic should point the '[*]' if source-location 8390 // information is added for it. 8391 diagnoseArrayStarInParamType(*this, PType, Param->getLocation()); 8392 8393 // MSVC destroys objects passed by value in the callee. Therefore a 8394 // function definition which takes such a parameter must be able to call the 8395 // object's destructor. However, we don't perform any direct access check 8396 // on the dtor. 8397 if (getLangOpts().CPlusPlus && Context.getTargetInfo() 8398 .getCXXABI() 8399 .areArgsDestroyedLeftToRightInCallee()) { 8400 if (!Param->isInvalidDecl()) { 8401 if (const RecordType *RT = Param->getType()->getAs<RecordType>()) { 8402 CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(RT->getDecl()); 8403 if (!ClassDecl->isInvalidDecl() && 8404 !ClassDecl->hasIrrelevantDestructor() && 8405 !ClassDecl->isDependentContext()) { 8406 CXXDestructorDecl *Destructor = LookupDestructor(ClassDecl); 8407 MarkFunctionReferenced(Param->getLocation(), Destructor); 8408 DiagnoseUseOfDecl(Destructor, Param->getLocation()); 8409 } 8410 } 8411 } 8412 } 8413 } 8414 8415 return HasInvalidParm; 8416 } 8417 8418 /// CheckCastAlign - Implements -Wcast-align, which warns when a 8419 /// pointer cast increases the alignment requirements. 8420 void Sema::CheckCastAlign(Expr *Op, QualType T, SourceRange TRange) { 8421 // This is actually a lot of work to potentially be doing on every 8422 // cast; don't do it if we're ignoring -Wcast_align (as is the default). 8423 if (getDiagnostics().isIgnored(diag::warn_cast_align, TRange.getBegin())) 8424 return; 8425 8426 // Ignore dependent types. 8427 if (T->isDependentType() || Op->getType()->isDependentType()) 8428 return; 8429 8430 // Require that the destination be a pointer type. 8431 const PointerType *DestPtr = T->getAs<PointerType>(); 8432 if (!DestPtr) return; 8433 8434 // If the destination has alignment 1, we're done. 8435 QualType DestPointee = DestPtr->getPointeeType(); 8436 if (DestPointee->isIncompleteType()) return; 8437 CharUnits DestAlign = Context.getTypeAlignInChars(DestPointee); 8438 if (DestAlign.isOne()) return; 8439 8440 // Require that the source be a pointer type. 8441 const PointerType *SrcPtr = Op->getType()->getAs<PointerType>(); 8442 if (!SrcPtr) return; 8443 QualType SrcPointee = SrcPtr->getPointeeType(); 8444 8445 // Whitelist casts from cv void*. We already implicitly 8446 // whitelisted casts to cv void*, since they have alignment 1. 8447 // Also whitelist casts involving incomplete types, which implicitly 8448 // includes 'void'. 8449 if (SrcPointee->isIncompleteType()) return; 8450 8451 CharUnits SrcAlign = Context.getTypeAlignInChars(SrcPointee); 8452 if (SrcAlign >= DestAlign) return; 8453 8454 Diag(TRange.getBegin(), diag::warn_cast_align) 8455 << Op->getType() << T 8456 << static_cast<unsigned>(SrcAlign.getQuantity()) 8457 << static_cast<unsigned>(DestAlign.getQuantity()) 8458 << TRange << Op->getSourceRange(); 8459 } 8460 8461 static const Type* getElementType(const Expr *BaseExpr) { 8462 const Type* EltType = BaseExpr->getType().getTypePtr(); 8463 if (EltType->isAnyPointerType()) 8464 return EltType->getPointeeType().getTypePtr(); 8465 else if (EltType->isArrayType()) 8466 return EltType->getBaseElementTypeUnsafe(); 8467 return EltType; 8468 } 8469 8470 /// \brief Check whether this array fits the idiom of a size-one tail padded 8471 /// array member of a struct. 8472 /// 8473 /// We avoid emitting out-of-bounds access warnings for such arrays as they are 8474 /// commonly used to emulate flexible arrays in C89 code. 8475 static bool IsTailPaddedMemberArray(Sema &S, llvm::APInt Size, 8476 const NamedDecl *ND) { 8477 if (Size != 1 || !ND) return false; 8478 8479 const FieldDecl *FD = dyn_cast<FieldDecl>(ND); 8480 if (!FD) return false; 8481 8482 // Don't consider sizes resulting from macro expansions or template argument 8483 // substitution to form C89 tail-padded arrays. 8484 8485 TypeSourceInfo *TInfo = FD->getTypeSourceInfo(); 8486 while (TInfo) { 8487 TypeLoc TL = TInfo->getTypeLoc(); 8488 // Look through typedefs. 8489 if (TypedefTypeLoc TTL = TL.getAs<TypedefTypeLoc>()) { 8490 const TypedefNameDecl *TDL = TTL.getTypedefNameDecl(); 8491 TInfo = TDL->getTypeSourceInfo(); 8492 continue; 8493 } 8494 if (ConstantArrayTypeLoc CTL = TL.getAs<ConstantArrayTypeLoc>()) { 8495 const Expr *SizeExpr = dyn_cast<IntegerLiteral>(CTL.getSizeExpr()); 8496 if (!SizeExpr || SizeExpr->getExprLoc().isMacroID()) 8497 return false; 8498 } 8499 break; 8500 } 8501 8502 const RecordDecl *RD = dyn_cast<RecordDecl>(FD->getDeclContext()); 8503 if (!RD) return false; 8504 if (RD->isUnion()) return false; 8505 if (const CXXRecordDecl *CRD = dyn_cast<CXXRecordDecl>(RD)) { 8506 if (!CRD->isStandardLayout()) return false; 8507 } 8508 8509 // See if this is the last field decl in the record. 8510 const Decl *D = FD; 8511 while ((D = D->getNextDeclInContext())) 8512 if (isa<FieldDecl>(D)) 8513 return false; 8514 return true; 8515 } 8516 8517 void Sema::CheckArrayAccess(const Expr *BaseExpr, const Expr *IndexExpr, 8518 const ArraySubscriptExpr *ASE, 8519 bool AllowOnePastEnd, bool IndexNegated) { 8520 IndexExpr = IndexExpr->IgnoreParenImpCasts(); 8521 if (IndexExpr->isValueDependent()) 8522 return; 8523 8524 const Type *EffectiveType = getElementType(BaseExpr); 8525 BaseExpr = BaseExpr->IgnoreParenCasts(); 8526 const ConstantArrayType *ArrayTy = 8527 Context.getAsConstantArrayType(BaseExpr->getType()); 8528 if (!ArrayTy) 8529 return; 8530 8531 llvm::APSInt index; 8532 if (!IndexExpr->EvaluateAsInt(index, Context)) 8533 return; 8534 if (IndexNegated) 8535 index = -index; 8536 8537 const NamedDecl *ND = nullptr; 8538 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(BaseExpr)) 8539 ND = dyn_cast<NamedDecl>(DRE->getDecl()); 8540 if (const MemberExpr *ME = dyn_cast<MemberExpr>(BaseExpr)) 8541 ND = dyn_cast<NamedDecl>(ME->getMemberDecl()); 8542 8543 if (index.isUnsigned() || !index.isNegative()) { 8544 llvm::APInt size = ArrayTy->getSize(); 8545 if (!size.isStrictlyPositive()) 8546 return; 8547 8548 const Type* BaseType = getElementType(BaseExpr); 8549 if (BaseType != EffectiveType) { 8550 // Make sure we're comparing apples to apples when comparing index to size 8551 uint64_t ptrarith_typesize = Context.getTypeSize(EffectiveType); 8552 uint64_t array_typesize = Context.getTypeSize(BaseType); 8553 // Handle ptrarith_typesize being zero, such as when casting to void* 8554 if (!ptrarith_typesize) ptrarith_typesize = 1; 8555 if (ptrarith_typesize != array_typesize) { 8556 // There's a cast to a different size type involved 8557 uint64_t ratio = array_typesize / ptrarith_typesize; 8558 // TODO: Be smarter about handling cases where array_typesize is not a 8559 // multiple of ptrarith_typesize 8560 if (ptrarith_typesize * ratio == array_typesize) 8561 size *= llvm::APInt(size.getBitWidth(), ratio); 8562 } 8563 } 8564 8565 if (size.getBitWidth() > index.getBitWidth()) 8566 index = index.zext(size.getBitWidth()); 8567 else if (size.getBitWidth() < index.getBitWidth()) 8568 size = size.zext(index.getBitWidth()); 8569 8570 // For array subscripting the index must be less than size, but for pointer 8571 // arithmetic also allow the index (offset) to be equal to size since 8572 // computing the next address after the end of the array is legal and 8573 // commonly done e.g. in C++ iterators and range-based for loops. 8574 if (AllowOnePastEnd ? index.ule(size) : index.ult(size)) 8575 return; 8576 8577 // Also don't warn for arrays of size 1 which are members of some 8578 // structure. These are often used to approximate flexible arrays in C89 8579 // code. 8580 if (IsTailPaddedMemberArray(*this, size, ND)) 8581 return; 8582 8583 // Suppress the warning if the subscript expression (as identified by the 8584 // ']' location) and the index expression are both from macro expansions 8585 // within a system header. 8586 if (ASE) { 8587 SourceLocation RBracketLoc = SourceMgr.getSpellingLoc( 8588 ASE->getRBracketLoc()); 8589 if (SourceMgr.isInSystemHeader(RBracketLoc)) { 8590 SourceLocation IndexLoc = SourceMgr.getSpellingLoc( 8591 IndexExpr->getLocStart()); 8592 if (SourceMgr.isWrittenInSameFile(RBracketLoc, IndexLoc)) 8593 return; 8594 } 8595 } 8596 8597 unsigned DiagID = diag::warn_ptr_arith_exceeds_bounds; 8598 if (ASE) 8599 DiagID = diag::warn_array_index_exceeds_bounds; 8600 8601 DiagRuntimeBehavior(BaseExpr->getLocStart(), BaseExpr, 8602 PDiag(DiagID) << index.toString(10, true) 8603 << size.toString(10, true) 8604 << (unsigned)size.getLimitedValue(~0U) 8605 << IndexExpr->getSourceRange()); 8606 } else { 8607 unsigned DiagID = diag::warn_array_index_precedes_bounds; 8608 if (!ASE) { 8609 DiagID = diag::warn_ptr_arith_precedes_bounds; 8610 if (index.isNegative()) index = -index; 8611 } 8612 8613 DiagRuntimeBehavior(BaseExpr->getLocStart(), BaseExpr, 8614 PDiag(DiagID) << index.toString(10, true) 8615 << IndexExpr->getSourceRange()); 8616 } 8617 8618 if (!ND) { 8619 // Try harder to find a NamedDecl to point at in the note. 8620 while (const ArraySubscriptExpr *ASE = 8621 dyn_cast<ArraySubscriptExpr>(BaseExpr)) 8622 BaseExpr = ASE->getBase()->IgnoreParenCasts(); 8623 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(BaseExpr)) 8624 ND = dyn_cast<NamedDecl>(DRE->getDecl()); 8625 if (const MemberExpr *ME = dyn_cast<MemberExpr>(BaseExpr)) 8626 ND = dyn_cast<NamedDecl>(ME->getMemberDecl()); 8627 } 8628 8629 if (ND) 8630 DiagRuntimeBehavior(ND->getLocStart(), BaseExpr, 8631 PDiag(diag::note_array_index_out_of_bounds) 8632 << ND->getDeclName()); 8633 } 8634 8635 void Sema::CheckArrayAccess(const Expr *expr) { 8636 int AllowOnePastEnd = 0; 8637 while (expr) { 8638 expr = expr->IgnoreParenImpCasts(); 8639 switch (expr->getStmtClass()) { 8640 case Stmt::ArraySubscriptExprClass: { 8641 const ArraySubscriptExpr *ASE = cast<ArraySubscriptExpr>(expr); 8642 CheckArrayAccess(ASE->getBase(), ASE->getIdx(), ASE, 8643 AllowOnePastEnd > 0); 8644 return; 8645 } 8646 case Stmt::OMPArraySectionExprClass: { 8647 const OMPArraySectionExpr *ASE = cast<OMPArraySectionExpr>(expr); 8648 if (ASE->getLowerBound()) 8649 CheckArrayAccess(ASE->getBase(), ASE->getLowerBound(), 8650 /*ASE=*/nullptr, AllowOnePastEnd > 0); 8651 return; 8652 } 8653 case Stmt::UnaryOperatorClass: { 8654 // Only unwrap the * and & unary operators 8655 const UnaryOperator *UO = cast<UnaryOperator>(expr); 8656 expr = UO->getSubExpr(); 8657 switch (UO->getOpcode()) { 8658 case UO_AddrOf: 8659 AllowOnePastEnd++; 8660 break; 8661 case UO_Deref: 8662 AllowOnePastEnd--; 8663 break; 8664 default: 8665 return; 8666 } 8667 break; 8668 } 8669 case Stmt::ConditionalOperatorClass: { 8670 const ConditionalOperator *cond = cast<ConditionalOperator>(expr); 8671 if (const Expr *lhs = cond->getLHS()) 8672 CheckArrayAccess(lhs); 8673 if (const Expr *rhs = cond->getRHS()) 8674 CheckArrayAccess(rhs); 8675 return; 8676 } 8677 default: 8678 return; 8679 } 8680 } 8681 } 8682 8683 //===--- CHECK: Objective-C retain cycles ----------------------------------// 8684 8685 namespace { 8686 struct RetainCycleOwner { 8687 RetainCycleOwner() : Variable(nullptr), Indirect(false) {} 8688 VarDecl *Variable; 8689 SourceRange Range; 8690 SourceLocation Loc; 8691 bool Indirect; 8692 8693 void setLocsFrom(Expr *e) { 8694 Loc = e->getExprLoc(); 8695 Range = e->getSourceRange(); 8696 } 8697 }; 8698 } 8699 8700 /// Consider whether capturing the given variable can possibly lead to 8701 /// a retain cycle. 8702 static bool considerVariable(VarDecl *var, Expr *ref, RetainCycleOwner &owner) { 8703 // In ARC, it's captured strongly iff the variable has __strong 8704 // lifetime. In MRR, it's captured strongly if the variable is 8705 // __block and has an appropriate type. 8706 if (var->getType().getObjCLifetime() != Qualifiers::OCL_Strong) 8707 return false; 8708 8709 owner.Variable = var; 8710 if (ref) 8711 owner.setLocsFrom(ref); 8712 return true; 8713 } 8714 8715 static bool findRetainCycleOwner(Sema &S, Expr *e, RetainCycleOwner &owner) { 8716 while (true) { 8717 e = e->IgnoreParens(); 8718 if (CastExpr *cast = dyn_cast<CastExpr>(e)) { 8719 switch (cast->getCastKind()) { 8720 case CK_BitCast: 8721 case CK_LValueBitCast: 8722 case CK_LValueToRValue: 8723 case CK_ARCReclaimReturnedObject: 8724 e = cast->getSubExpr(); 8725 continue; 8726 8727 default: 8728 return false; 8729 } 8730 } 8731 8732 if (ObjCIvarRefExpr *ref = dyn_cast<ObjCIvarRefExpr>(e)) { 8733 ObjCIvarDecl *ivar = ref->getDecl(); 8734 if (ivar->getType().getObjCLifetime() != Qualifiers::OCL_Strong) 8735 return false; 8736 8737 // Try to find a retain cycle in the base. 8738 if (!findRetainCycleOwner(S, ref->getBase(), owner)) 8739 return false; 8740 8741 if (ref->isFreeIvar()) owner.setLocsFrom(ref); 8742 owner.Indirect = true; 8743 return true; 8744 } 8745 8746 if (DeclRefExpr *ref = dyn_cast<DeclRefExpr>(e)) { 8747 VarDecl *var = dyn_cast<VarDecl>(ref->getDecl()); 8748 if (!var) return false; 8749 return considerVariable(var, ref, owner); 8750 } 8751 8752 if (MemberExpr *member = dyn_cast<MemberExpr>(e)) { 8753 if (member->isArrow()) return false; 8754 8755 // Don't count this as an indirect ownership. 8756 e = member->getBase(); 8757 continue; 8758 } 8759 8760 if (PseudoObjectExpr *pseudo = dyn_cast<PseudoObjectExpr>(e)) { 8761 // Only pay attention to pseudo-objects on property references. 8762 ObjCPropertyRefExpr *pre 8763 = dyn_cast<ObjCPropertyRefExpr>(pseudo->getSyntacticForm() 8764 ->IgnoreParens()); 8765 if (!pre) return false; 8766 if (pre->isImplicitProperty()) return false; 8767 ObjCPropertyDecl *property = pre->getExplicitProperty(); 8768 if (!property->isRetaining() && 8769 !(property->getPropertyIvarDecl() && 8770 property->getPropertyIvarDecl()->getType() 8771 .getObjCLifetime() == Qualifiers::OCL_Strong)) 8772 return false; 8773 8774 owner.Indirect = true; 8775 if (pre->isSuperReceiver()) { 8776 owner.Variable = S.getCurMethodDecl()->getSelfDecl(); 8777 if (!owner.Variable) 8778 return false; 8779 owner.Loc = pre->getLocation(); 8780 owner.Range = pre->getSourceRange(); 8781 return true; 8782 } 8783 e = const_cast<Expr*>(cast<OpaqueValueExpr>(pre->getBase()) 8784 ->getSourceExpr()); 8785 continue; 8786 } 8787 8788 // Array ivars? 8789 8790 return false; 8791 } 8792 } 8793 8794 namespace { 8795 struct FindCaptureVisitor : EvaluatedExprVisitor<FindCaptureVisitor> { 8796 FindCaptureVisitor(ASTContext &Context, VarDecl *variable) 8797 : EvaluatedExprVisitor<FindCaptureVisitor>(Context), 8798 Context(Context), Variable(variable), Capturer(nullptr), 8799 VarWillBeReased(false) {} 8800 ASTContext &Context; 8801 VarDecl *Variable; 8802 Expr *Capturer; 8803 bool VarWillBeReased; 8804 8805 void VisitDeclRefExpr(DeclRefExpr *ref) { 8806 if (ref->getDecl() == Variable && !Capturer) 8807 Capturer = ref; 8808 } 8809 8810 void VisitObjCIvarRefExpr(ObjCIvarRefExpr *ref) { 8811 if (Capturer) return; 8812 Visit(ref->getBase()); 8813 if (Capturer && ref->isFreeIvar()) 8814 Capturer = ref; 8815 } 8816 8817 void VisitBlockExpr(BlockExpr *block) { 8818 // Look inside nested blocks 8819 if (block->getBlockDecl()->capturesVariable(Variable)) 8820 Visit(block->getBlockDecl()->getBody()); 8821 } 8822 8823 void VisitOpaqueValueExpr(OpaqueValueExpr *OVE) { 8824 if (Capturer) return; 8825 if (OVE->getSourceExpr()) 8826 Visit(OVE->getSourceExpr()); 8827 } 8828 void VisitBinaryOperator(BinaryOperator *BinOp) { 8829 if (!Variable || VarWillBeReased || BinOp->getOpcode() != BO_Assign) 8830 return; 8831 Expr *LHS = BinOp->getLHS(); 8832 if (const DeclRefExpr *DRE = dyn_cast_or_null<DeclRefExpr>(LHS)) { 8833 if (DRE->getDecl() != Variable) 8834 return; 8835 if (Expr *RHS = BinOp->getRHS()) { 8836 RHS = RHS->IgnoreParenCasts(); 8837 llvm::APSInt Value; 8838 VarWillBeReased = 8839 (RHS && RHS->isIntegerConstantExpr(Value, Context) && Value == 0); 8840 } 8841 } 8842 } 8843 }; 8844 } 8845 8846 /// Check whether the given argument is a block which captures a 8847 /// variable. 8848 static Expr *findCapturingExpr(Sema &S, Expr *e, RetainCycleOwner &owner) { 8849 assert(owner.Variable && owner.Loc.isValid()); 8850 8851 e = e->IgnoreParenCasts(); 8852 8853 // Look through [^{...} copy] and Block_copy(^{...}). 8854 if (ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(e)) { 8855 Selector Cmd = ME->getSelector(); 8856 if (Cmd.isUnarySelector() && Cmd.getNameForSlot(0) == "copy") { 8857 e = ME->getInstanceReceiver(); 8858 if (!e) 8859 return nullptr; 8860 e = e->IgnoreParenCasts(); 8861 } 8862 } else if (CallExpr *CE = dyn_cast<CallExpr>(e)) { 8863 if (CE->getNumArgs() == 1) { 8864 FunctionDecl *Fn = dyn_cast_or_null<FunctionDecl>(CE->getCalleeDecl()); 8865 if (Fn) { 8866 const IdentifierInfo *FnI = Fn->getIdentifier(); 8867 if (FnI && FnI->isStr("_Block_copy")) { 8868 e = CE->getArg(0)->IgnoreParenCasts(); 8869 } 8870 } 8871 } 8872 } 8873 8874 BlockExpr *block = dyn_cast<BlockExpr>(e); 8875 if (!block || !block->getBlockDecl()->capturesVariable(owner.Variable)) 8876 return nullptr; 8877 8878 FindCaptureVisitor visitor(S.Context, owner.Variable); 8879 visitor.Visit(block->getBlockDecl()->getBody()); 8880 return visitor.VarWillBeReased ? nullptr : visitor.Capturer; 8881 } 8882 8883 static void diagnoseRetainCycle(Sema &S, Expr *capturer, 8884 RetainCycleOwner &owner) { 8885 assert(capturer); 8886 assert(owner.Variable && owner.Loc.isValid()); 8887 8888 S.Diag(capturer->getExprLoc(), diag::warn_arc_retain_cycle) 8889 << owner.Variable << capturer->getSourceRange(); 8890 S.Diag(owner.Loc, diag::note_arc_retain_cycle_owner) 8891 << owner.Indirect << owner.Range; 8892 } 8893 8894 /// Check for a keyword selector that starts with the word 'add' or 8895 /// 'set'. 8896 static bool isSetterLikeSelector(Selector sel) { 8897 if (sel.isUnarySelector()) return false; 8898 8899 StringRef str = sel.getNameForSlot(0); 8900 while (!str.empty() && str.front() == '_') str = str.substr(1); 8901 if (str.startswith("set")) 8902 str = str.substr(3); 8903 else if (str.startswith("add")) { 8904 // Specially whitelist 'addOperationWithBlock:'. 8905 if (sel.getNumArgs() == 1 && str.startswith("addOperationWithBlock")) 8906 return false; 8907 str = str.substr(3); 8908 } 8909 else 8910 return false; 8911 8912 if (str.empty()) return true; 8913 return !isLowercase(str.front()); 8914 } 8915 8916 static Optional<int> GetNSMutableArrayArgumentIndex(Sema &S, 8917 ObjCMessageExpr *Message) { 8918 bool IsMutableArray = S.NSAPIObj->isSubclassOfNSClass( 8919 Message->getReceiverInterface(), 8920 NSAPI::ClassId_NSMutableArray); 8921 if (!IsMutableArray) { 8922 return None; 8923 } 8924 8925 Selector Sel = Message->getSelector(); 8926 8927 Optional<NSAPI::NSArrayMethodKind> MKOpt = 8928 S.NSAPIObj->getNSArrayMethodKind(Sel); 8929 if (!MKOpt) { 8930 return None; 8931 } 8932 8933 NSAPI::NSArrayMethodKind MK = *MKOpt; 8934 8935 switch (MK) { 8936 case NSAPI::NSMutableArr_addObject: 8937 case NSAPI::NSMutableArr_insertObjectAtIndex: 8938 case NSAPI::NSMutableArr_setObjectAtIndexedSubscript: 8939 return 0; 8940 case NSAPI::NSMutableArr_replaceObjectAtIndex: 8941 return 1; 8942 8943 default: 8944 return None; 8945 } 8946 8947 return None; 8948 } 8949 8950 static 8951 Optional<int> GetNSMutableDictionaryArgumentIndex(Sema &S, 8952 ObjCMessageExpr *Message) { 8953 bool IsMutableDictionary = S.NSAPIObj->isSubclassOfNSClass( 8954 Message->getReceiverInterface(), 8955 NSAPI::ClassId_NSMutableDictionary); 8956 if (!IsMutableDictionary) { 8957 return None; 8958 } 8959 8960 Selector Sel = Message->getSelector(); 8961 8962 Optional<NSAPI::NSDictionaryMethodKind> MKOpt = 8963 S.NSAPIObj->getNSDictionaryMethodKind(Sel); 8964 if (!MKOpt) { 8965 return None; 8966 } 8967 8968 NSAPI::NSDictionaryMethodKind MK = *MKOpt; 8969 8970 switch (MK) { 8971 case NSAPI::NSMutableDict_setObjectForKey: 8972 case NSAPI::NSMutableDict_setValueForKey: 8973 case NSAPI::NSMutableDict_setObjectForKeyedSubscript: 8974 return 0; 8975 8976 default: 8977 return None; 8978 } 8979 8980 return None; 8981 } 8982 8983 static Optional<int> GetNSSetArgumentIndex(Sema &S, ObjCMessageExpr *Message) { 8984 bool IsMutableSet = S.NSAPIObj->isSubclassOfNSClass( 8985 Message->getReceiverInterface(), 8986 NSAPI::ClassId_NSMutableSet); 8987 8988 bool IsMutableOrderedSet = S.NSAPIObj->isSubclassOfNSClass( 8989 Message->getReceiverInterface(), 8990 NSAPI::ClassId_NSMutableOrderedSet); 8991 if (!IsMutableSet && !IsMutableOrderedSet) { 8992 return None; 8993 } 8994 8995 Selector Sel = Message->getSelector(); 8996 8997 Optional<NSAPI::NSSetMethodKind> MKOpt = S.NSAPIObj->getNSSetMethodKind(Sel); 8998 if (!MKOpt) { 8999 return None; 9000 } 9001 9002 NSAPI::NSSetMethodKind MK = *MKOpt; 9003 9004 switch (MK) { 9005 case NSAPI::NSMutableSet_addObject: 9006 case NSAPI::NSOrderedSet_setObjectAtIndex: 9007 case NSAPI::NSOrderedSet_setObjectAtIndexedSubscript: 9008 case NSAPI::NSOrderedSet_insertObjectAtIndex: 9009 return 0; 9010 case NSAPI::NSOrderedSet_replaceObjectAtIndexWithObject: 9011 return 1; 9012 } 9013 9014 return None; 9015 } 9016 9017 void Sema::CheckObjCCircularContainer(ObjCMessageExpr *Message) { 9018 if (!Message->isInstanceMessage()) { 9019 return; 9020 } 9021 9022 Optional<int> ArgOpt; 9023 9024 if (!(ArgOpt = GetNSMutableArrayArgumentIndex(*this, Message)) && 9025 !(ArgOpt = GetNSMutableDictionaryArgumentIndex(*this, Message)) && 9026 !(ArgOpt = GetNSSetArgumentIndex(*this, Message))) { 9027 return; 9028 } 9029 9030 int ArgIndex = *ArgOpt; 9031 9032 Expr *Arg = Message->getArg(ArgIndex)->IgnoreImpCasts(); 9033 if (OpaqueValueExpr *OE = dyn_cast<OpaqueValueExpr>(Arg)) { 9034 Arg = OE->getSourceExpr()->IgnoreImpCasts(); 9035 } 9036 9037 if (Message->getReceiverKind() == ObjCMessageExpr::SuperInstance) { 9038 if (DeclRefExpr *ArgRE = dyn_cast<DeclRefExpr>(Arg)) { 9039 if (ArgRE->isObjCSelfExpr()) { 9040 Diag(Message->getSourceRange().getBegin(), 9041 diag::warn_objc_circular_container) 9042 << ArgRE->getDecl()->getName() << StringRef("super"); 9043 } 9044 } 9045 } else { 9046 Expr *Receiver = Message->getInstanceReceiver()->IgnoreImpCasts(); 9047 9048 if (OpaqueValueExpr *OE = dyn_cast<OpaqueValueExpr>(Receiver)) { 9049 Receiver = OE->getSourceExpr()->IgnoreImpCasts(); 9050 } 9051 9052 if (DeclRefExpr *ReceiverRE = dyn_cast<DeclRefExpr>(Receiver)) { 9053 if (DeclRefExpr *ArgRE = dyn_cast<DeclRefExpr>(Arg)) { 9054 if (ReceiverRE->getDecl() == ArgRE->getDecl()) { 9055 ValueDecl *Decl = ReceiverRE->getDecl(); 9056 Diag(Message->getSourceRange().getBegin(), 9057 diag::warn_objc_circular_container) 9058 << Decl->getName() << Decl->getName(); 9059 if (!ArgRE->isObjCSelfExpr()) { 9060 Diag(Decl->getLocation(), 9061 diag::note_objc_circular_container_declared_here) 9062 << Decl->getName(); 9063 } 9064 } 9065 } 9066 } else if (ObjCIvarRefExpr *IvarRE = dyn_cast<ObjCIvarRefExpr>(Receiver)) { 9067 if (ObjCIvarRefExpr *IvarArgRE = dyn_cast<ObjCIvarRefExpr>(Arg)) { 9068 if (IvarRE->getDecl() == IvarArgRE->getDecl()) { 9069 ObjCIvarDecl *Decl = IvarRE->getDecl(); 9070 Diag(Message->getSourceRange().getBegin(), 9071 diag::warn_objc_circular_container) 9072 << Decl->getName() << Decl->getName(); 9073 Diag(Decl->getLocation(), 9074 diag::note_objc_circular_container_declared_here) 9075 << Decl->getName(); 9076 } 9077 } 9078 } 9079 } 9080 9081 } 9082 9083 /// Check a message send to see if it's likely to cause a retain cycle. 9084 void Sema::checkRetainCycles(ObjCMessageExpr *msg) { 9085 // Only check instance methods whose selector looks like a setter. 9086 if (!msg->isInstanceMessage() || !isSetterLikeSelector(msg->getSelector())) 9087 return; 9088 9089 // Try to find a variable that the receiver is strongly owned by. 9090 RetainCycleOwner owner; 9091 if (msg->getReceiverKind() == ObjCMessageExpr::Instance) { 9092 if (!findRetainCycleOwner(*this, msg->getInstanceReceiver(), owner)) 9093 return; 9094 } else { 9095 assert(msg->getReceiverKind() == ObjCMessageExpr::SuperInstance); 9096 owner.Variable = getCurMethodDecl()->getSelfDecl(); 9097 owner.Loc = msg->getSuperLoc(); 9098 owner.Range = msg->getSuperLoc(); 9099 } 9100 9101 // Check whether the receiver is captured by any of the arguments. 9102 for (unsigned i = 0, e = msg->getNumArgs(); i != e; ++i) 9103 if (Expr *capturer = findCapturingExpr(*this, msg->getArg(i), owner)) 9104 return diagnoseRetainCycle(*this, capturer, owner); 9105 } 9106 9107 /// Check a property assign to see if it's likely to cause a retain cycle. 9108 void Sema::checkRetainCycles(Expr *receiver, Expr *argument) { 9109 RetainCycleOwner owner; 9110 if (!findRetainCycleOwner(*this, receiver, owner)) 9111 return; 9112 9113 if (Expr *capturer = findCapturingExpr(*this, argument, owner)) 9114 diagnoseRetainCycle(*this, capturer, owner); 9115 } 9116 9117 void Sema::checkRetainCycles(VarDecl *Var, Expr *Init) { 9118 RetainCycleOwner Owner; 9119 if (!considerVariable(Var, /*DeclRefExpr=*/nullptr, Owner)) 9120 return; 9121 9122 // Because we don't have an expression for the variable, we have to set the 9123 // location explicitly here. 9124 Owner.Loc = Var->getLocation(); 9125 Owner.Range = Var->getSourceRange(); 9126 9127 if (Expr *Capturer = findCapturingExpr(*this, Init, Owner)) 9128 diagnoseRetainCycle(*this, Capturer, Owner); 9129 } 9130 9131 static bool checkUnsafeAssignLiteral(Sema &S, SourceLocation Loc, 9132 Expr *RHS, bool isProperty) { 9133 // Check if RHS is an Objective-C object literal, which also can get 9134 // immediately zapped in a weak reference. Note that we explicitly 9135 // allow ObjCStringLiterals, since those are designed to never really die. 9136 RHS = RHS->IgnoreParenImpCasts(); 9137 9138 // This enum needs to match with the 'select' in 9139 // warn_objc_arc_literal_assign (off-by-1). 9140 Sema::ObjCLiteralKind Kind = S.CheckLiteralKind(RHS); 9141 if (Kind == Sema::LK_String || Kind == Sema::LK_None) 9142 return false; 9143 9144 S.Diag(Loc, diag::warn_arc_literal_assign) 9145 << (unsigned) Kind 9146 << (isProperty ? 0 : 1) 9147 << RHS->getSourceRange(); 9148 9149 return true; 9150 } 9151 9152 static bool checkUnsafeAssignObject(Sema &S, SourceLocation Loc, 9153 Qualifiers::ObjCLifetime LT, 9154 Expr *RHS, bool isProperty) { 9155 // Strip off any implicit cast added to get to the one ARC-specific. 9156 while (ImplicitCastExpr *cast = dyn_cast<ImplicitCastExpr>(RHS)) { 9157 if (cast->getCastKind() == CK_ARCConsumeObject) { 9158 S.Diag(Loc, diag::warn_arc_retained_assign) 9159 << (LT == Qualifiers::OCL_ExplicitNone) 9160 << (isProperty ? 0 : 1) 9161 << RHS->getSourceRange(); 9162 return true; 9163 } 9164 RHS = cast->getSubExpr(); 9165 } 9166 9167 if (LT == Qualifiers::OCL_Weak && 9168 checkUnsafeAssignLiteral(S, Loc, RHS, isProperty)) 9169 return true; 9170 9171 return false; 9172 } 9173 9174 bool Sema::checkUnsafeAssigns(SourceLocation Loc, 9175 QualType LHS, Expr *RHS) { 9176 Qualifiers::ObjCLifetime LT = LHS.getObjCLifetime(); 9177 9178 if (LT != Qualifiers::OCL_Weak && LT != Qualifiers::OCL_ExplicitNone) 9179 return false; 9180 9181 if (checkUnsafeAssignObject(*this, Loc, LT, RHS, false)) 9182 return true; 9183 9184 return false; 9185 } 9186 9187 void Sema::checkUnsafeExprAssigns(SourceLocation Loc, 9188 Expr *LHS, Expr *RHS) { 9189 QualType LHSType; 9190 // PropertyRef on LHS type need be directly obtained from 9191 // its declaration as it has a PseudoType. 9192 ObjCPropertyRefExpr *PRE 9193 = dyn_cast<ObjCPropertyRefExpr>(LHS->IgnoreParens()); 9194 if (PRE && !PRE->isImplicitProperty()) { 9195 const ObjCPropertyDecl *PD = PRE->getExplicitProperty(); 9196 if (PD) 9197 LHSType = PD->getType(); 9198 } 9199 9200 if (LHSType.isNull()) 9201 LHSType = LHS->getType(); 9202 9203 Qualifiers::ObjCLifetime LT = LHSType.getObjCLifetime(); 9204 9205 if (LT == Qualifiers::OCL_Weak) { 9206 if (!Diags.isIgnored(diag::warn_arc_repeated_use_of_weak, Loc)) 9207 getCurFunction()->markSafeWeakUse(LHS); 9208 } 9209 9210 if (checkUnsafeAssigns(Loc, LHSType, RHS)) 9211 return; 9212 9213 // FIXME. Check for other life times. 9214 if (LT != Qualifiers::OCL_None) 9215 return; 9216 9217 if (PRE) { 9218 if (PRE->isImplicitProperty()) 9219 return; 9220 const ObjCPropertyDecl *PD = PRE->getExplicitProperty(); 9221 if (!PD) 9222 return; 9223 9224 unsigned Attributes = PD->getPropertyAttributes(); 9225 if (Attributes & ObjCPropertyDecl::OBJC_PR_assign) { 9226 // when 'assign' attribute was not explicitly specified 9227 // by user, ignore it and rely on property type itself 9228 // for lifetime info. 9229 unsigned AsWrittenAttr = PD->getPropertyAttributesAsWritten(); 9230 if (!(AsWrittenAttr & ObjCPropertyDecl::OBJC_PR_assign) && 9231 LHSType->isObjCRetainableType()) 9232 return; 9233 9234 while (ImplicitCastExpr *cast = dyn_cast<ImplicitCastExpr>(RHS)) { 9235 if (cast->getCastKind() == CK_ARCConsumeObject) { 9236 Diag(Loc, diag::warn_arc_retained_property_assign) 9237 << RHS->getSourceRange(); 9238 return; 9239 } 9240 RHS = cast->getSubExpr(); 9241 } 9242 } 9243 else if (Attributes & ObjCPropertyDecl::OBJC_PR_weak) { 9244 if (checkUnsafeAssignObject(*this, Loc, Qualifiers::OCL_Weak, RHS, true)) 9245 return; 9246 } 9247 } 9248 } 9249 9250 //===--- CHECK: Empty statement body (-Wempty-body) ---------------------===// 9251 9252 namespace { 9253 bool ShouldDiagnoseEmptyStmtBody(const SourceManager &SourceMgr, 9254 SourceLocation StmtLoc, 9255 const NullStmt *Body) { 9256 // Do not warn if the body is a macro that expands to nothing, e.g: 9257 // 9258 // #define CALL(x) 9259 // if (condition) 9260 // CALL(0); 9261 // 9262 if (Body->hasLeadingEmptyMacro()) 9263 return false; 9264 9265 // Get line numbers of statement and body. 9266 bool StmtLineInvalid; 9267 unsigned StmtLine = SourceMgr.getPresumedLineNumber(StmtLoc, 9268 &StmtLineInvalid); 9269 if (StmtLineInvalid) 9270 return false; 9271 9272 bool BodyLineInvalid; 9273 unsigned BodyLine = SourceMgr.getSpellingLineNumber(Body->getSemiLoc(), 9274 &BodyLineInvalid); 9275 if (BodyLineInvalid) 9276 return false; 9277 9278 // Warn if null statement and body are on the same line. 9279 if (StmtLine != BodyLine) 9280 return false; 9281 9282 return true; 9283 } 9284 } // Unnamed namespace 9285 9286 void Sema::DiagnoseEmptyStmtBody(SourceLocation StmtLoc, 9287 const Stmt *Body, 9288 unsigned DiagID) { 9289 // Since this is a syntactic check, don't emit diagnostic for template 9290 // instantiations, this just adds noise. 9291 if (CurrentInstantiationScope) 9292 return; 9293 9294 // The body should be a null statement. 9295 const NullStmt *NBody = dyn_cast<NullStmt>(Body); 9296 if (!NBody) 9297 return; 9298 9299 // Do the usual checks. 9300 if (!ShouldDiagnoseEmptyStmtBody(SourceMgr, StmtLoc, NBody)) 9301 return; 9302 9303 Diag(NBody->getSemiLoc(), DiagID); 9304 Diag(NBody->getSemiLoc(), diag::note_empty_body_on_separate_line); 9305 } 9306 9307 void Sema::DiagnoseEmptyLoopBody(const Stmt *S, 9308 const Stmt *PossibleBody) { 9309 assert(!CurrentInstantiationScope); // Ensured by caller 9310 9311 SourceLocation StmtLoc; 9312 const Stmt *Body; 9313 unsigned DiagID; 9314 if (const ForStmt *FS = dyn_cast<ForStmt>(S)) { 9315 StmtLoc = FS->getRParenLoc(); 9316 Body = FS->getBody(); 9317 DiagID = diag::warn_empty_for_body; 9318 } else if (const WhileStmt *WS = dyn_cast<WhileStmt>(S)) { 9319 StmtLoc = WS->getCond()->getSourceRange().getEnd(); 9320 Body = WS->getBody(); 9321 DiagID = diag::warn_empty_while_body; 9322 } else 9323 return; // Neither `for' nor `while'. 9324 9325 // The body should be a null statement. 9326 const NullStmt *NBody = dyn_cast<NullStmt>(Body); 9327 if (!NBody) 9328 return; 9329 9330 // Skip expensive checks if diagnostic is disabled. 9331 if (Diags.isIgnored(DiagID, NBody->getSemiLoc())) 9332 return; 9333 9334 // Do the usual checks. 9335 if (!ShouldDiagnoseEmptyStmtBody(SourceMgr, StmtLoc, NBody)) 9336 return; 9337 9338 // `for(...);' and `while(...);' are popular idioms, so in order to keep 9339 // noise level low, emit diagnostics only if for/while is followed by a 9340 // CompoundStmt, e.g.: 9341 // for (int i = 0; i < n; i++); 9342 // { 9343 // a(i); 9344 // } 9345 // or if for/while is followed by a statement with more indentation 9346 // than for/while itself: 9347 // for (int i = 0; i < n; i++); 9348 // a(i); 9349 bool ProbableTypo = isa<CompoundStmt>(PossibleBody); 9350 if (!ProbableTypo) { 9351 bool BodyColInvalid; 9352 unsigned BodyCol = SourceMgr.getPresumedColumnNumber( 9353 PossibleBody->getLocStart(), 9354 &BodyColInvalid); 9355 if (BodyColInvalid) 9356 return; 9357 9358 bool StmtColInvalid; 9359 unsigned StmtCol = SourceMgr.getPresumedColumnNumber( 9360 S->getLocStart(), 9361 &StmtColInvalid); 9362 if (StmtColInvalid) 9363 return; 9364 9365 if (BodyCol > StmtCol) 9366 ProbableTypo = true; 9367 } 9368 9369 if (ProbableTypo) { 9370 Diag(NBody->getSemiLoc(), DiagID); 9371 Diag(NBody->getSemiLoc(), diag::note_empty_body_on_separate_line); 9372 } 9373 } 9374 9375 //===--- CHECK: Warn on self move with std::move. -------------------------===// 9376 9377 /// DiagnoseSelfMove - Emits a warning if a value is moved to itself. 9378 void Sema::DiagnoseSelfMove(const Expr *LHSExpr, const Expr *RHSExpr, 9379 SourceLocation OpLoc) { 9380 9381 if (Diags.isIgnored(diag::warn_sizeof_pointer_expr_memaccess, OpLoc)) 9382 return; 9383 9384 if (!ActiveTemplateInstantiations.empty()) 9385 return; 9386 9387 // Strip parens and casts away. 9388 LHSExpr = LHSExpr->IgnoreParenImpCasts(); 9389 RHSExpr = RHSExpr->IgnoreParenImpCasts(); 9390 9391 // Check for a call expression 9392 const CallExpr *CE = dyn_cast<CallExpr>(RHSExpr); 9393 if (!CE || CE->getNumArgs() != 1) 9394 return; 9395 9396 // Check for a call to std::move 9397 const FunctionDecl *FD = CE->getDirectCallee(); 9398 if (!FD || !FD->isInStdNamespace() || !FD->getIdentifier() || 9399 !FD->getIdentifier()->isStr("move")) 9400 return; 9401 9402 // Get argument from std::move 9403 RHSExpr = CE->getArg(0); 9404 9405 const DeclRefExpr *LHSDeclRef = dyn_cast<DeclRefExpr>(LHSExpr); 9406 const DeclRefExpr *RHSDeclRef = dyn_cast<DeclRefExpr>(RHSExpr); 9407 9408 // Two DeclRefExpr's, check that the decls are the same. 9409 if (LHSDeclRef && RHSDeclRef) { 9410 if (!LHSDeclRef->getDecl() || !RHSDeclRef->getDecl()) 9411 return; 9412 if (LHSDeclRef->getDecl()->getCanonicalDecl() != 9413 RHSDeclRef->getDecl()->getCanonicalDecl()) 9414 return; 9415 9416 Diag(OpLoc, diag::warn_self_move) << LHSExpr->getType() 9417 << LHSExpr->getSourceRange() 9418 << RHSExpr->getSourceRange(); 9419 return; 9420 } 9421 9422 // Member variables require a different approach to check for self moves. 9423 // MemberExpr's are the same if every nested MemberExpr refers to the same 9424 // Decl and that the base Expr's are DeclRefExpr's with the same Decl or 9425 // the base Expr's are CXXThisExpr's. 9426 const Expr *LHSBase = LHSExpr; 9427 const Expr *RHSBase = RHSExpr; 9428 const MemberExpr *LHSME = dyn_cast<MemberExpr>(LHSExpr); 9429 const MemberExpr *RHSME = dyn_cast<MemberExpr>(RHSExpr); 9430 if (!LHSME || !RHSME) 9431 return; 9432 9433 while (LHSME && RHSME) { 9434 if (LHSME->getMemberDecl()->getCanonicalDecl() != 9435 RHSME->getMemberDecl()->getCanonicalDecl()) 9436 return; 9437 9438 LHSBase = LHSME->getBase(); 9439 RHSBase = RHSME->getBase(); 9440 LHSME = dyn_cast<MemberExpr>(LHSBase); 9441 RHSME = dyn_cast<MemberExpr>(RHSBase); 9442 } 9443 9444 LHSDeclRef = dyn_cast<DeclRefExpr>(LHSBase); 9445 RHSDeclRef = dyn_cast<DeclRefExpr>(RHSBase); 9446 if (LHSDeclRef && RHSDeclRef) { 9447 if (!LHSDeclRef->getDecl() || !RHSDeclRef->getDecl()) 9448 return; 9449 if (LHSDeclRef->getDecl()->getCanonicalDecl() != 9450 RHSDeclRef->getDecl()->getCanonicalDecl()) 9451 return; 9452 9453 Diag(OpLoc, diag::warn_self_move) << LHSExpr->getType() 9454 << LHSExpr->getSourceRange() 9455 << RHSExpr->getSourceRange(); 9456 return; 9457 } 9458 9459 if (isa<CXXThisExpr>(LHSBase) && isa<CXXThisExpr>(RHSBase)) 9460 Diag(OpLoc, diag::warn_self_move) << LHSExpr->getType() 9461 << LHSExpr->getSourceRange() 9462 << RHSExpr->getSourceRange(); 9463 } 9464 9465 //===--- Layout compatibility ----------------------------------------------// 9466 9467 namespace { 9468 9469 bool isLayoutCompatible(ASTContext &C, QualType T1, QualType T2); 9470 9471 /// \brief Check if two enumeration types are layout-compatible. 9472 bool isLayoutCompatible(ASTContext &C, EnumDecl *ED1, EnumDecl *ED2) { 9473 // C++11 [dcl.enum] p8: 9474 // Two enumeration types are layout-compatible if they have the same 9475 // underlying type. 9476 return ED1->isComplete() && ED2->isComplete() && 9477 C.hasSameType(ED1->getIntegerType(), ED2->getIntegerType()); 9478 } 9479 9480 /// \brief Check if two fields are layout-compatible. 9481 bool isLayoutCompatible(ASTContext &C, FieldDecl *Field1, FieldDecl *Field2) { 9482 if (!isLayoutCompatible(C, Field1->getType(), Field2->getType())) 9483 return false; 9484 9485 if (Field1->isBitField() != Field2->isBitField()) 9486 return false; 9487 9488 if (Field1->isBitField()) { 9489 // Make sure that the bit-fields are the same length. 9490 unsigned Bits1 = Field1->getBitWidthValue(C); 9491 unsigned Bits2 = Field2->getBitWidthValue(C); 9492 9493 if (Bits1 != Bits2) 9494 return false; 9495 } 9496 9497 return true; 9498 } 9499 9500 /// \brief Check if two standard-layout structs are layout-compatible. 9501 /// (C++11 [class.mem] p17) 9502 bool isLayoutCompatibleStruct(ASTContext &C, 9503 RecordDecl *RD1, 9504 RecordDecl *RD2) { 9505 // If both records are C++ classes, check that base classes match. 9506 if (const CXXRecordDecl *D1CXX = dyn_cast<CXXRecordDecl>(RD1)) { 9507 // If one of records is a CXXRecordDecl we are in C++ mode, 9508 // thus the other one is a CXXRecordDecl, too. 9509 const CXXRecordDecl *D2CXX = cast<CXXRecordDecl>(RD2); 9510 // Check number of base classes. 9511 if (D1CXX->getNumBases() != D2CXX->getNumBases()) 9512 return false; 9513 9514 // Check the base classes. 9515 for (CXXRecordDecl::base_class_const_iterator 9516 Base1 = D1CXX->bases_begin(), 9517 BaseEnd1 = D1CXX->bases_end(), 9518 Base2 = D2CXX->bases_begin(); 9519 Base1 != BaseEnd1; 9520 ++Base1, ++Base2) { 9521 if (!isLayoutCompatible(C, Base1->getType(), Base2->getType())) 9522 return false; 9523 } 9524 } else if (const CXXRecordDecl *D2CXX = dyn_cast<CXXRecordDecl>(RD2)) { 9525 // If only RD2 is a C++ class, it should have zero base classes. 9526 if (D2CXX->getNumBases() > 0) 9527 return false; 9528 } 9529 9530 // Check the fields. 9531 RecordDecl::field_iterator Field2 = RD2->field_begin(), 9532 Field2End = RD2->field_end(), 9533 Field1 = RD1->field_begin(), 9534 Field1End = RD1->field_end(); 9535 for ( ; Field1 != Field1End && Field2 != Field2End; ++Field1, ++Field2) { 9536 if (!isLayoutCompatible(C, *Field1, *Field2)) 9537 return false; 9538 } 9539 if (Field1 != Field1End || Field2 != Field2End) 9540 return false; 9541 9542 return true; 9543 } 9544 9545 /// \brief Check if two standard-layout unions are layout-compatible. 9546 /// (C++11 [class.mem] p18) 9547 bool isLayoutCompatibleUnion(ASTContext &C, 9548 RecordDecl *RD1, 9549 RecordDecl *RD2) { 9550 llvm::SmallPtrSet<FieldDecl *, 8> UnmatchedFields; 9551 for (auto *Field2 : RD2->fields()) 9552 UnmatchedFields.insert(Field2); 9553 9554 for (auto *Field1 : RD1->fields()) { 9555 llvm::SmallPtrSet<FieldDecl *, 8>::iterator 9556 I = UnmatchedFields.begin(), 9557 E = UnmatchedFields.end(); 9558 9559 for ( ; I != E; ++I) { 9560 if (isLayoutCompatible(C, Field1, *I)) { 9561 bool Result = UnmatchedFields.erase(*I); 9562 (void) Result; 9563 assert(Result); 9564 break; 9565 } 9566 } 9567 if (I == E) 9568 return false; 9569 } 9570 9571 return UnmatchedFields.empty(); 9572 } 9573 9574 bool isLayoutCompatible(ASTContext &C, RecordDecl *RD1, RecordDecl *RD2) { 9575 if (RD1->isUnion() != RD2->isUnion()) 9576 return false; 9577 9578 if (RD1->isUnion()) 9579 return isLayoutCompatibleUnion(C, RD1, RD2); 9580 else 9581 return isLayoutCompatibleStruct(C, RD1, RD2); 9582 } 9583 9584 /// \brief Check if two types are layout-compatible in C++11 sense. 9585 bool isLayoutCompatible(ASTContext &C, QualType T1, QualType T2) { 9586 if (T1.isNull() || T2.isNull()) 9587 return false; 9588 9589 // C++11 [basic.types] p11: 9590 // If two types T1 and T2 are the same type, then T1 and T2 are 9591 // layout-compatible types. 9592 if (C.hasSameType(T1, T2)) 9593 return true; 9594 9595 T1 = T1.getCanonicalType().getUnqualifiedType(); 9596 T2 = T2.getCanonicalType().getUnqualifiedType(); 9597 9598 const Type::TypeClass TC1 = T1->getTypeClass(); 9599 const Type::TypeClass TC2 = T2->getTypeClass(); 9600 9601 if (TC1 != TC2) 9602 return false; 9603 9604 if (TC1 == Type::Enum) { 9605 return isLayoutCompatible(C, 9606 cast<EnumType>(T1)->getDecl(), 9607 cast<EnumType>(T2)->getDecl()); 9608 } else if (TC1 == Type::Record) { 9609 if (!T1->isStandardLayoutType() || !T2->isStandardLayoutType()) 9610 return false; 9611 9612 return isLayoutCompatible(C, 9613 cast<RecordType>(T1)->getDecl(), 9614 cast<RecordType>(T2)->getDecl()); 9615 } 9616 9617 return false; 9618 } 9619 } 9620 9621 //===--- CHECK: pointer_with_type_tag attribute: datatypes should match ----// 9622 9623 namespace { 9624 /// \brief Given a type tag expression find the type tag itself. 9625 /// 9626 /// \param TypeExpr Type tag expression, as it appears in user's code. 9627 /// 9628 /// \param VD Declaration of an identifier that appears in a type tag. 9629 /// 9630 /// \param MagicValue Type tag magic value. 9631 bool FindTypeTagExpr(const Expr *TypeExpr, const ASTContext &Ctx, 9632 const ValueDecl **VD, uint64_t *MagicValue) { 9633 while(true) { 9634 if (!TypeExpr) 9635 return false; 9636 9637 TypeExpr = TypeExpr->IgnoreParenImpCasts()->IgnoreParenCasts(); 9638 9639 switch (TypeExpr->getStmtClass()) { 9640 case Stmt::UnaryOperatorClass: { 9641 const UnaryOperator *UO = cast<UnaryOperator>(TypeExpr); 9642 if (UO->getOpcode() == UO_AddrOf || UO->getOpcode() == UO_Deref) { 9643 TypeExpr = UO->getSubExpr(); 9644 continue; 9645 } 9646 return false; 9647 } 9648 9649 case Stmt::DeclRefExprClass: { 9650 const DeclRefExpr *DRE = cast<DeclRefExpr>(TypeExpr); 9651 *VD = DRE->getDecl(); 9652 return true; 9653 } 9654 9655 case Stmt::IntegerLiteralClass: { 9656 const IntegerLiteral *IL = cast<IntegerLiteral>(TypeExpr); 9657 llvm::APInt MagicValueAPInt = IL->getValue(); 9658 if (MagicValueAPInt.getActiveBits() <= 64) { 9659 *MagicValue = MagicValueAPInt.getZExtValue(); 9660 return true; 9661 } else 9662 return false; 9663 } 9664 9665 case Stmt::BinaryConditionalOperatorClass: 9666 case Stmt::ConditionalOperatorClass: { 9667 const AbstractConditionalOperator *ACO = 9668 cast<AbstractConditionalOperator>(TypeExpr); 9669 bool Result; 9670 if (ACO->getCond()->EvaluateAsBooleanCondition(Result, Ctx)) { 9671 if (Result) 9672 TypeExpr = ACO->getTrueExpr(); 9673 else 9674 TypeExpr = ACO->getFalseExpr(); 9675 continue; 9676 } 9677 return false; 9678 } 9679 9680 case Stmt::BinaryOperatorClass: { 9681 const BinaryOperator *BO = cast<BinaryOperator>(TypeExpr); 9682 if (BO->getOpcode() == BO_Comma) { 9683 TypeExpr = BO->getRHS(); 9684 continue; 9685 } 9686 return false; 9687 } 9688 9689 default: 9690 return false; 9691 } 9692 } 9693 } 9694 9695 /// \brief Retrieve the C type corresponding to type tag TypeExpr. 9696 /// 9697 /// \param TypeExpr Expression that specifies a type tag. 9698 /// 9699 /// \param MagicValues Registered magic values. 9700 /// 9701 /// \param FoundWrongKind Set to true if a type tag was found, but of a wrong 9702 /// kind. 9703 /// 9704 /// \param TypeInfo Information about the corresponding C type. 9705 /// 9706 /// \returns true if the corresponding C type was found. 9707 bool GetMatchingCType( 9708 const IdentifierInfo *ArgumentKind, 9709 const Expr *TypeExpr, const ASTContext &Ctx, 9710 const llvm::DenseMap<Sema::TypeTagMagicValue, 9711 Sema::TypeTagData> *MagicValues, 9712 bool &FoundWrongKind, 9713 Sema::TypeTagData &TypeInfo) { 9714 FoundWrongKind = false; 9715 9716 // Variable declaration that has type_tag_for_datatype attribute. 9717 const ValueDecl *VD = nullptr; 9718 9719 uint64_t MagicValue; 9720 9721 if (!FindTypeTagExpr(TypeExpr, Ctx, &VD, &MagicValue)) 9722 return false; 9723 9724 if (VD) { 9725 if (TypeTagForDatatypeAttr *I = VD->getAttr<TypeTagForDatatypeAttr>()) { 9726 if (I->getArgumentKind() != ArgumentKind) { 9727 FoundWrongKind = true; 9728 return false; 9729 } 9730 TypeInfo.Type = I->getMatchingCType(); 9731 TypeInfo.LayoutCompatible = I->getLayoutCompatible(); 9732 TypeInfo.MustBeNull = I->getMustBeNull(); 9733 return true; 9734 } 9735 return false; 9736 } 9737 9738 if (!MagicValues) 9739 return false; 9740 9741 llvm::DenseMap<Sema::TypeTagMagicValue, 9742 Sema::TypeTagData>::const_iterator I = 9743 MagicValues->find(std::make_pair(ArgumentKind, MagicValue)); 9744 if (I == MagicValues->end()) 9745 return false; 9746 9747 TypeInfo = I->second; 9748 return true; 9749 } 9750 } // unnamed namespace 9751 9752 void Sema::RegisterTypeTagForDatatype(const IdentifierInfo *ArgumentKind, 9753 uint64_t MagicValue, QualType Type, 9754 bool LayoutCompatible, 9755 bool MustBeNull) { 9756 if (!TypeTagForDatatypeMagicValues) 9757 TypeTagForDatatypeMagicValues.reset( 9758 new llvm::DenseMap<TypeTagMagicValue, TypeTagData>); 9759 9760 TypeTagMagicValue Magic(ArgumentKind, MagicValue); 9761 (*TypeTagForDatatypeMagicValues)[Magic] = 9762 TypeTagData(Type, LayoutCompatible, MustBeNull); 9763 } 9764 9765 namespace { 9766 bool IsSameCharType(QualType T1, QualType T2) { 9767 const BuiltinType *BT1 = T1->getAs<BuiltinType>(); 9768 if (!BT1) 9769 return false; 9770 9771 const BuiltinType *BT2 = T2->getAs<BuiltinType>(); 9772 if (!BT2) 9773 return false; 9774 9775 BuiltinType::Kind T1Kind = BT1->getKind(); 9776 BuiltinType::Kind T2Kind = BT2->getKind(); 9777 9778 return (T1Kind == BuiltinType::SChar && T2Kind == BuiltinType::Char_S) || 9779 (T1Kind == BuiltinType::UChar && T2Kind == BuiltinType::Char_U) || 9780 (T1Kind == BuiltinType::Char_U && T2Kind == BuiltinType::UChar) || 9781 (T1Kind == BuiltinType::Char_S && T2Kind == BuiltinType::SChar); 9782 } 9783 } // unnamed namespace 9784 9785 void Sema::CheckArgumentWithTypeTag(const ArgumentWithTypeTagAttr *Attr, 9786 const Expr * const *ExprArgs) { 9787 const IdentifierInfo *ArgumentKind = Attr->getArgumentKind(); 9788 bool IsPointerAttr = Attr->getIsPointer(); 9789 9790 const Expr *TypeTagExpr = ExprArgs[Attr->getTypeTagIdx()]; 9791 bool FoundWrongKind; 9792 TypeTagData TypeInfo; 9793 if (!GetMatchingCType(ArgumentKind, TypeTagExpr, Context, 9794 TypeTagForDatatypeMagicValues.get(), 9795 FoundWrongKind, TypeInfo)) { 9796 if (FoundWrongKind) 9797 Diag(TypeTagExpr->getExprLoc(), 9798 diag::warn_type_tag_for_datatype_wrong_kind) 9799 << TypeTagExpr->getSourceRange(); 9800 return; 9801 } 9802 9803 const Expr *ArgumentExpr = ExprArgs[Attr->getArgumentIdx()]; 9804 if (IsPointerAttr) { 9805 // Skip implicit cast of pointer to `void *' (as a function argument). 9806 if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(ArgumentExpr)) 9807 if (ICE->getType()->isVoidPointerType() && 9808 ICE->getCastKind() == CK_BitCast) 9809 ArgumentExpr = ICE->getSubExpr(); 9810 } 9811 QualType ArgumentType = ArgumentExpr->getType(); 9812 9813 // Passing a `void*' pointer shouldn't trigger a warning. 9814 if (IsPointerAttr && ArgumentType->isVoidPointerType()) 9815 return; 9816 9817 if (TypeInfo.MustBeNull) { 9818 // Type tag with matching void type requires a null pointer. 9819 if (!ArgumentExpr->isNullPointerConstant(Context, 9820 Expr::NPC_ValueDependentIsNotNull)) { 9821 Diag(ArgumentExpr->getExprLoc(), 9822 diag::warn_type_safety_null_pointer_required) 9823 << ArgumentKind->getName() 9824 << ArgumentExpr->getSourceRange() 9825 << TypeTagExpr->getSourceRange(); 9826 } 9827 return; 9828 } 9829 9830 QualType RequiredType = TypeInfo.Type; 9831 if (IsPointerAttr) 9832 RequiredType = Context.getPointerType(RequiredType); 9833 9834 bool mismatch = false; 9835 if (!TypeInfo.LayoutCompatible) { 9836 mismatch = !Context.hasSameType(ArgumentType, RequiredType); 9837 9838 // C++11 [basic.fundamental] p1: 9839 // Plain char, signed char, and unsigned char are three distinct types. 9840 // 9841 // But we treat plain `char' as equivalent to `signed char' or `unsigned 9842 // char' depending on the current char signedness mode. 9843 if (mismatch) 9844 if ((IsPointerAttr && IsSameCharType(ArgumentType->getPointeeType(), 9845 RequiredType->getPointeeType())) || 9846 (!IsPointerAttr && IsSameCharType(ArgumentType, RequiredType))) 9847 mismatch = false; 9848 } else 9849 if (IsPointerAttr) 9850 mismatch = !isLayoutCompatible(Context, 9851 ArgumentType->getPointeeType(), 9852 RequiredType->getPointeeType()); 9853 else 9854 mismatch = !isLayoutCompatible(Context, ArgumentType, RequiredType); 9855 9856 if (mismatch) 9857 Diag(ArgumentExpr->getExprLoc(), diag::warn_type_safety_type_mismatch) 9858 << ArgumentType << ArgumentKind 9859 << TypeInfo.LayoutCompatible << RequiredType 9860 << ArgumentExpr->getSourceRange() 9861 << TypeTagExpr->getSourceRange(); 9862 } 9863 9864