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/StmtCXX.h" 25 #include "clang/AST/StmtObjC.h" 26 #include "clang/Analysis/Analyses/FormatString.h" 27 #include "clang/Basic/CharInfo.h" 28 #include "clang/Basic/TargetBuiltins.h" 29 #include "clang/Basic/TargetInfo.h" 30 #include "clang/Lex/Lexer.h" // TODO: Extract static functions to fix layering. 31 #include "clang/Sema/Initialization.h" 32 #include "clang/Sema/Lookup.h" 33 #include "clang/Sema/ScopeInfo.h" 34 #include "clang/Sema/Sema.h" 35 #include "llvm/ADT/STLExtras.h" 36 #include "llvm/ADT/SmallBitVector.h" 37 #include "llvm/ADT/SmallString.h" 38 #include "llvm/Support/ConvertUTF.h" 39 #include "llvm/Support/raw_ostream.h" 40 #include <limits> 41 using namespace clang; 42 using namespace sema; 43 44 SourceLocation Sema::getLocationOfStringLiteralByte(const StringLiteral *SL, 45 unsigned ByteNo) const { 46 return SL->getLocationOfByte(ByteNo, getSourceManager(), LangOpts, 47 Context.getTargetInfo()); 48 } 49 50 /// Checks that a call expression's argument count is the desired number. 51 /// This is useful when doing custom type-checking. Returns true on error. 52 static bool checkArgCount(Sema &S, CallExpr *call, unsigned desiredArgCount) { 53 unsigned argCount = call->getNumArgs(); 54 if (argCount == desiredArgCount) return false; 55 56 if (argCount < desiredArgCount) 57 return S.Diag(call->getLocEnd(), diag::err_typecheck_call_too_few_args) 58 << 0 /*function call*/ << desiredArgCount << argCount 59 << call->getSourceRange(); 60 61 // Highlight all the excess arguments. 62 SourceRange range(call->getArg(desiredArgCount)->getLocStart(), 63 call->getArg(argCount - 1)->getLocEnd()); 64 65 return S.Diag(range.getBegin(), diag::err_typecheck_call_too_many_args) 66 << 0 /*function call*/ << desiredArgCount << argCount 67 << call->getArg(1)->getSourceRange(); 68 } 69 70 /// Check that the first argument to __builtin_annotation is an integer 71 /// and the second argument is a non-wide string literal. 72 static bool SemaBuiltinAnnotation(Sema &S, CallExpr *TheCall) { 73 if (checkArgCount(S, TheCall, 2)) 74 return true; 75 76 // First argument should be an integer. 77 Expr *ValArg = TheCall->getArg(0); 78 QualType Ty = ValArg->getType(); 79 if (!Ty->isIntegerType()) { 80 S.Diag(ValArg->getLocStart(), diag::err_builtin_annotation_first_arg) 81 << ValArg->getSourceRange(); 82 return true; 83 } 84 85 // Second argument should be a constant string. 86 Expr *StrArg = TheCall->getArg(1)->IgnoreParenCasts(); 87 StringLiteral *Literal = dyn_cast<StringLiteral>(StrArg); 88 if (!Literal || !Literal->isAscii()) { 89 S.Diag(StrArg->getLocStart(), diag::err_builtin_annotation_second_arg) 90 << StrArg->getSourceRange(); 91 return true; 92 } 93 94 TheCall->setType(Ty); 95 return false; 96 } 97 98 /// Check that the argument to __builtin_addressof is a glvalue, and set the 99 /// result type to the corresponding pointer type. 100 static bool SemaBuiltinAddressof(Sema &S, CallExpr *TheCall) { 101 if (checkArgCount(S, TheCall, 1)) 102 return true; 103 104 ExprResult Arg(TheCall->getArg(0)); 105 QualType ResultType = S.CheckAddressOfOperand(Arg, TheCall->getLocStart()); 106 if (ResultType.isNull()) 107 return true; 108 109 TheCall->setArg(0, Arg.get()); 110 TheCall->setType(ResultType); 111 return false; 112 } 113 114 static void SemaBuiltinMemChkCall(Sema &S, FunctionDecl *FDecl, 115 CallExpr *TheCall, unsigned SizeIdx, 116 unsigned DstSizeIdx) { 117 if (TheCall->getNumArgs() <= SizeIdx || 118 TheCall->getNumArgs() <= DstSizeIdx) 119 return; 120 121 const Expr *SizeArg = TheCall->getArg(SizeIdx); 122 const Expr *DstSizeArg = TheCall->getArg(DstSizeIdx); 123 124 llvm::APSInt Size, DstSize; 125 126 // find out if both sizes are known at compile time 127 if (!SizeArg->EvaluateAsInt(Size, S.Context) || 128 !DstSizeArg->EvaluateAsInt(DstSize, S.Context)) 129 return; 130 131 if (Size.ule(DstSize)) 132 return; 133 134 // confirmed overflow so generate the diagnostic. 135 IdentifierInfo *FnName = FDecl->getIdentifier(); 136 SourceLocation SL = TheCall->getLocStart(); 137 SourceRange SR = TheCall->getSourceRange(); 138 139 S.Diag(SL, diag::warn_memcpy_chk_overflow) << SR << FnName; 140 } 141 142 static bool SemaBuiltinCallWithStaticChain(Sema &S, CallExpr *BuiltinCall) { 143 if (checkArgCount(S, BuiltinCall, 2)) 144 return true; 145 146 SourceLocation BuiltinLoc = BuiltinCall->getLocStart(); 147 Expr *Builtin = BuiltinCall->getCallee()->IgnoreImpCasts(); 148 Expr *Call = BuiltinCall->getArg(0); 149 Expr *Chain = BuiltinCall->getArg(1); 150 151 if (Call->getStmtClass() != Stmt::CallExprClass) { 152 S.Diag(BuiltinLoc, diag::err_first_argument_to_cwsc_not_call) 153 << Call->getSourceRange(); 154 return true; 155 } 156 157 auto CE = cast<CallExpr>(Call); 158 if (CE->getCallee()->getType()->isBlockPointerType()) { 159 S.Diag(BuiltinLoc, diag::err_first_argument_to_cwsc_block_call) 160 << Call->getSourceRange(); 161 return true; 162 } 163 164 const Decl *TargetDecl = CE->getCalleeDecl(); 165 if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(TargetDecl)) 166 if (FD->getBuiltinID()) { 167 S.Diag(BuiltinLoc, diag::err_first_argument_to_cwsc_builtin_call) 168 << Call->getSourceRange(); 169 return true; 170 } 171 172 if (isa<CXXPseudoDestructorExpr>(CE->getCallee()->IgnoreParens())) { 173 S.Diag(BuiltinLoc, diag::err_first_argument_to_cwsc_pdtor_call) 174 << Call->getSourceRange(); 175 return true; 176 } 177 178 ExprResult ChainResult = S.UsualUnaryConversions(Chain); 179 if (ChainResult.isInvalid()) 180 return true; 181 if (!ChainResult.get()->getType()->isPointerType()) { 182 S.Diag(BuiltinLoc, diag::err_second_argument_to_cwsc_not_pointer) 183 << Chain->getSourceRange(); 184 return true; 185 } 186 187 QualType ReturnTy = CE->getCallReturnType(); 188 QualType ArgTys[2] = { ReturnTy, ChainResult.get()->getType() }; 189 QualType BuiltinTy = S.Context.getFunctionType( 190 ReturnTy, ArgTys, FunctionProtoType::ExtProtoInfo()); 191 QualType BuiltinPtrTy = S.Context.getPointerType(BuiltinTy); 192 193 Builtin = 194 S.ImpCastExprToType(Builtin, BuiltinPtrTy, CK_BuiltinFnToFnPtr).get(); 195 196 BuiltinCall->setType(CE->getType()); 197 BuiltinCall->setValueKind(CE->getValueKind()); 198 BuiltinCall->setObjectKind(CE->getObjectKind()); 199 BuiltinCall->setCallee(Builtin); 200 BuiltinCall->setArg(1, ChainResult.get()); 201 202 return false; 203 } 204 205 static bool SemaBuiltinSEHScopeCheck(Sema &SemaRef, CallExpr *TheCall, 206 Scope::ScopeFlags NeededScopeFlags, 207 unsigned DiagID) { 208 // Scopes aren't available during instantiation. Fortunately, builtin 209 // functions cannot be template args so they cannot be formed through template 210 // instantiation. Therefore checking once during the parse is sufficient. 211 if (!SemaRef.ActiveTemplateInstantiations.empty()) 212 return false; 213 214 Scope *S = SemaRef.getCurScope(); 215 while (S && !S->isSEHExceptScope()) 216 S = S->getParent(); 217 if (!S || !(S->getFlags() & NeededScopeFlags)) { 218 auto *DRE = cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts()); 219 SemaRef.Diag(TheCall->getExprLoc(), DiagID) 220 << DRE->getDecl()->getIdentifier(); 221 return true; 222 } 223 224 return false; 225 } 226 227 ExprResult 228 Sema::CheckBuiltinFunctionCall(FunctionDecl *FDecl, unsigned BuiltinID, 229 CallExpr *TheCall) { 230 ExprResult TheCallResult(TheCall); 231 232 // Find out if any arguments are required to be integer constant expressions. 233 unsigned ICEArguments = 0; 234 ASTContext::GetBuiltinTypeError Error; 235 Context.GetBuiltinType(BuiltinID, Error, &ICEArguments); 236 if (Error != ASTContext::GE_None) 237 ICEArguments = 0; // Don't diagnose previously diagnosed errors. 238 239 // If any arguments are required to be ICE's, check and diagnose. 240 for (unsigned ArgNo = 0; ICEArguments != 0; ++ArgNo) { 241 // Skip arguments not required to be ICE's. 242 if ((ICEArguments & (1 << ArgNo)) == 0) continue; 243 244 llvm::APSInt Result; 245 if (SemaBuiltinConstantArg(TheCall, ArgNo, Result)) 246 return true; 247 ICEArguments &= ~(1 << ArgNo); 248 } 249 250 switch (BuiltinID) { 251 case Builtin::BI__builtin___CFStringMakeConstantString: 252 assert(TheCall->getNumArgs() == 1 && 253 "Wrong # arguments to builtin CFStringMakeConstantString"); 254 if (CheckObjCString(TheCall->getArg(0))) 255 return ExprError(); 256 break; 257 case Builtin::BI__builtin_stdarg_start: 258 case Builtin::BI__builtin_va_start: 259 if (SemaBuiltinVAStart(TheCall)) 260 return ExprError(); 261 break; 262 case Builtin::BI__va_start: { 263 switch (Context.getTargetInfo().getTriple().getArch()) { 264 case llvm::Triple::arm: 265 case llvm::Triple::thumb: 266 if (SemaBuiltinVAStartARM(TheCall)) 267 return ExprError(); 268 break; 269 default: 270 if (SemaBuiltinVAStart(TheCall)) 271 return ExprError(); 272 break; 273 } 274 break; 275 } 276 case Builtin::BI__builtin_isgreater: 277 case Builtin::BI__builtin_isgreaterequal: 278 case Builtin::BI__builtin_isless: 279 case Builtin::BI__builtin_islessequal: 280 case Builtin::BI__builtin_islessgreater: 281 case Builtin::BI__builtin_isunordered: 282 if (SemaBuiltinUnorderedCompare(TheCall)) 283 return ExprError(); 284 break; 285 case Builtin::BI__builtin_fpclassify: 286 if (SemaBuiltinFPClassification(TheCall, 6)) 287 return ExprError(); 288 break; 289 case Builtin::BI__builtin_isfinite: 290 case Builtin::BI__builtin_isinf: 291 case Builtin::BI__builtin_isinf_sign: 292 case Builtin::BI__builtin_isnan: 293 case Builtin::BI__builtin_isnormal: 294 if (SemaBuiltinFPClassification(TheCall, 1)) 295 return ExprError(); 296 break; 297 case Builtin::BI__builtin_shufflevector: 298 return SemaBuiltinShuffleVector(TheCall); 299 // TheCall will be freed by the smart pointer here, but that's fine, since 300 // SemaBuiltinShuffleVector guts it, but then doesn't release it. 301 case Builtin::BI__builtin_prefetch: 302 if (SemaBuiltinPrefetch(TheCall)) 303 return ExprError(); 304 break; 305 case Builtin::BI__assume: 306 case Builtin::BI__builtin_assume: 307 if (SemaBuiltinAssume(TheCall)) 308 return ExprError(); 309 break; 310 case Builtin::BI__builtin_assume_aligned: 311 if (SemaBuiltinAssumeAligned(TheCall)) 312 return ExprError(); 313 break; 314 case Builtin::BI__builtin_object_size: 315 if (SemaBuiltinConstantArgRange(TheCall, 1, 0, 3)) 316 return ExprError(); 317 break; 318 case Builtin::BI__builtin_longjmp: 319 if (SemaBuiltinLongjmp(TheCall)) 320 return ExprError(); 321 break; 322 323 case Builtin::BI__builtin_classify_type: 324 if (checkArgCount(*this, TheCall, 1)) return true; 325 TheCall->setType(Context.IntTy); 326 break; 327 case Builtin::BI__builtin_constant_p: 328 if (checkArgCount(*this, TheCall, 1)) return true; 329 TheCall->setType(Context.IntTy); 330 break; 331 case Builtin::BI__sync_fetch_and_add: 332 case Builtin::BI__sync_fetch_and_add_1: 333 case Builtin::BI__sync_fetch_and_add_2: 334 case Builtin::BI__sync_fetch_and_add_4: 335 case Builtin::BI__sync_fetch_and_add_8: 336 case Builtin::BI__sync_fetch_and_add_16: 337 case Builtin::BI__sync_fetch_and_sub: 338 case Builtin::BI__sync_fetch_and_sub_1: 339 case Builtin::BI__sync_fetch_and_sub_2: 340 case Builtin::BI__sync_fetch_and_sub_4: 341 case Builtin::BI__sync_fetch_and_sub_8: 342 case Builtin::BI__sync_fetch_and_sub_16: 343 case Builtin::BI__sync_fetch_and_or: 344 case Builtin::BI__sync_fetch_and_or_1: 345 case Builtin::BI__sync_fetch_and_or_2: 346 case Builtin::BI__sync_fetch_and_or_4: 347 case Builtin::BI__sync_fetch_and_or_8: 348 case Builtin::BI__sync_fetch_and_or_16: 349 case Builtin::BI__sync_fetch_and_and: 350 case Builtin::BI__sync_fetch_and_and_1: 351 case Builtin::BI__sync_fetch_and_and_2: 352 case Builtin::BI__sync_fetch_and_and_4: 353 case Builtin::BI__sync_fetch_and_and_8: 354 case Builtin::BI__sync_fetch_and_and_16: 355 case Builtin::BI__sync_fetch_and_xor: 356 case Builtin::BI__sync_fetch_and_xor_1: 357 case Builtin::BI__sync_fetch_and_xor_2: 358 case Builtin::BI__sync_fetch_and_xor_4: 359 case Builtin::BI__sync_fetch_and_xor_8: 360 case Builtin::BI__sync_fetch_and_xor_16: 361 case Builtin::BI__sync_fetch_and_nand: 362 case Builtin::BI__sync_fetch_and_nand_1: 363 case Builtin::BI__sync_fetch_and_nand_2: 364 case Builtin::BI__sync_fetch_and_nand_4: 365 case Builtin::BI__sync_fetch_and_nand_8: 366 case Builtin::BI__sync_fetch_and_nand_16: 367 case Builtin::BI__sync_add_and_fetch: 368 case Builtin::BI__sync_add_and_fetch_1: 369 case Builtin::BI__sync_add_and_fetch_2: 370 case Builtin::BI__sync_add_and_fetch_4: 371 case Builtin::BI__sync_add_and_fetch_8: 372 case Builtin::BI__sync_add_and_fetch_16: 373 case Builtin::BI__sync_sub_and_fetch: 374 case Builtin::BI__sync_sub_and_fetch_1: 375 case Builtin::BI__sync_sub_and_fetch_2: 376 case Builtin::BI__sync_sub_and_fetch_4: 377 case Builtin::BI__sync_sub_and_fetch_8: 378 case Builtin::BI__sync_sub_and_fetch_16: 379 case Builtin::BI__sync_and_and_fetch: 380 case Builtin::BI__sync_and_and_fetch_1: 381 case Builtin::BI__sync_and_and_fetch_2: 382 case Builtin::BI__sync_and_and_fetch_4: 383 case Builtin::BI__sync_and_and_fetch_8: 384 case Builtin::BI__sync_and_and_fetch_16: 385 case Builtin::BI__sync_or_and_fetch: 386 case Builtin::BI__sync_or_and_fetch_1: 387 case Builtin::BI__sync_or_and_fetch_2: 388 case Builtin::BI__sync_or_and_fetch_4: 389 case Builtin::BI__sync_or_and_fetch_8: 390 case Builtin::BI__sync_or_and_fetch_16: 391 case Builtin::BI__sync_xor_and_fetch: 392 case Builtin::BI__sync_xor_and_fetch_1: 393 case Builtin::BI__sync_xor_and_fetch_2: 394 case Builtin::BI__sync_xor_and_fetch_4: 395 case Builtin::BI__sync_xor_and_fetch_8: 396 case Builtin::BI__sync_xor_and_fetch_16: 397 case Builtin::BI__sync_nand_and_fetch: 398 case Builtin::BI__sync_nand_and_fetch_1: 399 case Builtin::BI__sync_nand_and_fetch_2: 400 case Builtin::BI__sync_nand_and_fetch_4: 401 case Builtin::BI__sync_nand_and_fetch_8: 402 case Builtin::BI__sync_nand_and_fetch_16: 403 case Builtin::BI__sync_val_compare_and_swap: 404 case Builtin::BI__sync_val_compare_and_swap_1: 405 case Builtin::BI__sync_val_compare_and_swap_2: 406 case Builtin::BI__sync_val_compare_and_swap_4: 407 case Builtin::BI__sync_val_compare_and_swap_8: 408 case Builtin::BI__sync_val_compare_and_swap_16: 409 case Builtin::BI__sync_bool_compare_and_swap: 410 case Builtin::BI__sync_bool_compare_and_swap_1: 411 case Builtin::BI__sync_bool_compare_and_swap_2: 412 case Builtin::BI__sync_bool_compare_and_swap_4: 413 case Builtin::BI__sync_bool_compare_and_swap_8: 414 case Builtin::BI__sync_bool_compare_and_swap_16: 415 case Builtin::BI__sync_lock_test_and_set: 416 case Builtin::BI__sync_lock_test_and_set_1: 417 case Builtin::BI__sync_lock_test_and_set_2: 418 case Builtin::BI__sync_lock_test_and_set_4: 419 case Builtin::BI__sync_lock_test_and_set_8: 420 case Builtin::BI__sync_lock_test_and_set_16: 421 case Builtin::BI__sync_lock_release: 422 case Builtin::BI__sync_lock_release_1: 423 case Builtin::BI__sync_lock_release_2: 424 case Builtin::BI__sync_lock_release_4: 425 case Builtin::BI__sync_lock_release_8: 426 case Builtin::BI__sync_lock_release_16: 427 case Builtin::BI__sync_swap: 428 case Builtin::BI__sync_swap_1: 429 case Builtin::BI__sync_swap_2: 430 case Builtin::BI__sync_swap_4: 431 case Builtin::BI__sync_swap_8: 432 case Builtin::BI__sync_swap_16: 433 return SemaBuiltinAtomicOverloaded(TheCallResult); 434 #define BUILTIN(ID, TYPE, ATTRS) 435 #define ATOMIC_BUILTIN(ID, TYPE, ATTRS) \ 436 case Builtin::BI##ID: \ 437 return SemaAtomicOpsOverloaded(TheCallResult, AtomicExpr::AO##ID); 438 #include "clang/Basic/Builtins.def" 439 case Builtin::BI__builtin_annotation: 440 if (SemaBuiltinAnnotation(*this, TheCall)) 441 return ExprError(); 442 break; 443 case Builtin::BI__builtin_addressof: 444 if (SemaBuiltinAddressof(*this, TheCall)) 445 return ExprError(); 446 break; 447 case Builtin::BI__builtin_operator_new: 448 case Builtin::BI__builtin_operator_delete: 449 if (!getLangOpts().CPlusPlus) { 450 Diag(TheCall->getExprLoc(), diag::err_builtin_requires_language) 451 << (BuiltinID == Builtin::BI__builtin_operator_new 452 ? "__builtin_operator_new" 453 : "__builtin_operator_delete") 454 << "C++"; 455 return ExprError(); 456 } 457 // CodeGen assumes it can find the global new and delete to call, 458 // so ensure that they are declared. 459 DeclareGlobalNewDelete(); 460 break; 461 462 // check secure string manipulation functions where overflows 463 // are detectable at compile time 464 case Builtin::BI__builtin___memcpy_chk: 465 case Builtin::BI__builtin___memmove_chk: 466 case Builtin::BI__builtin___memset_chk: 467 case Builtin::BI__builtin___strlcat_chk: 468 case Builtin::BI__builtin___strlcpy_chk: 469 case Builtin::BI__builtin___strncat_chk: 470 case Builtin::BI__builtin___strncpy_chk: 471 case Builtin::BI__builtin___stpncpy_chk: 472 SemaBuiltinMemChkCall(*this, FDecl, TheCall, 2, 3); 473 break; 474 case Builtin::BI__builtin___memccpy_chk: 475 SemaBuiltinMemChkCall(*this, FDecl, TheCall, 3, 4); 476 break; 477 case Builtin::BI__builtin___snprintf_chk: 478 case Builtin::BI__builtin___vsnprintf_chk: 479 SemaBuiltinMemChkCall(*this, FDecl, TheCall, 1, 3); 480 break; 481 482 case Builtin::BI__builtin_call_with_static_chain: 483 if (SemaBuiltinCallWithStaticChain(*this, TheCall)) 484 return ExprError(); 485 break; 486 487 case Builtin::BI__exception_code: 488 case Builtin::BI_exception_code: { 489 if (SemaBuiltinSEHScopeCheck(*this, TheCall, Scope::SEHExceptScope, 490 diag::err_seh___except_block)) 491 return ExprError(); 492 break; 493 } 494 case Builtin::BI__exception_info: 495 case Builtin::BI_exception_info: { 496 if (SemaBuiltinSEHScopeCheck(*this, TheCall, Scope::SEHFilterScope, 497 diag::err_seh___except_filter)) 498 return ExprError(); 499 break; 500 } 501 502 } 503 504 // Since the target specific builtins for each arch overlap, only check those 505 // of the arch we are compiling for. 506 if (BuiltinID >= Builtin::FirstTSBuiltin) { 507 switch (Context.getTargetInfo().getTriple().getArch()) { 508 case llvm::Triple::arm: 509 case llvm::Triple::armeb: 510 case llvm::Triple::thumb: 511 case llvm::Triple::thumbeb: 512 if (CheckARMBuiltinFunctionCall(BuiltinID, TheCall)) 513 return ExprError(); 514 break; 515 case llvm::Triple::aarch64: 516 case llvm::Triple::aarch64_be: 517 if (CheckAArch64BuiltinFunctionCall(BuiltinID, TheCall)) 518 return ExprError(); 519 break; 520 case llvm::Triple::mips: 521 case llvm::Triple::mipsel: 522 case llvm::Triple::mips64: 523 case llvm::Triple::mips64el: 524 if (CheckMipsBuiltinFunctionCall(BuiltinID, TheCall)) 525 return ExprError(); 526 break; 527 case llvm::Triple::x86: 528 case llvm::Triple::x86_64: 529 if (CheckX86BuiltinFunctionCall(BuiltinID, TheCall)) 530 return ExprError(); 531 break; 532 default: 533 break; 534 } 535 } 536 537 return TheCallResult; 538 } 539 540 // Get the valid immediate range for the specified NEON type code. 541 static unsigned RFT(unsigned t, bool shift = false, bool ForceQuad = false) { 542 NeonTypeFlags Type(t); 543 int IsQuad = ForceQuad ? true : Type.isQuad(); 544 switch (Type.getEltType()) { 545 case NeonTypeFlags::Int8: 546 case NeonTypeFlags::Poly8: 547 return shift ? 7 : (8 << IsQuad) - 1; 548 case NeonTypeFlags::Int16: 549 case NeonTypeFlags::Poly16: 550 return shift ? 15 : (4 << IsQuad) - 1; 551 case NeonTypeFlags::Int32: 552 return shift ? 31 : (2 << IsQuad) - 1; 553 case NeonTypeFlags::Int64: 554 case NeonTypeFlags::Poly64: 555 return shift ? 63 : (1 << IsQuad) - 1; 556 case NeonTypeFlags::Poly128: 557 return shift ? 127 : (1 << IsQuad) - 1; 558 case NeonTypeFlags::Float16: 559 assert(!shift && "cannot shift float types!"); 560 return (4 << IsQuad) - 1; 561 case NeonTypeFlags::Float32: 562 assert(!shift && "cannot shift float types!"); 563 return (2 << IsQuad) - 1; 564 case NeonTypeFlags::Float64: 565 assert(!shift && "cannot shift float types!"); 566 return (1 << IsQuad) - 1; 567 } 568 llvm_unreachable("Invalid NeonTypeFlag!"); 569 } 570 571 /// getNeonEltType - Return the QualType corresponding to the elements of 572 /// the vector type specified by the NeonTypeFlags. This is used to check 573 /// the pointer arguments for Neon load/store intrinsics. 574 static QualType getNeonEltType(NeonTypeFlags Flags, ASTContext &Context, 575 bool IsPolyUnsigned, bool IsInt64Long) { 576 switch (Flags.getEltType()) { 577 case NeonTypeFlags::Int8: 578 return Flags.isUnsigned() ? Context.UnsignedCharTy : Context.SignedCharTy; 579 case NeonTypeFlags::Int16: 580 return Flags.isUnsigned() ? Context.UnsignedShortTy : Context.ShortTy; 581 case NeonTypeFlags::Int32: 582 return Flags.isUnsigned() ? Context.UnsignedIntTy : Context.IntTy; 583 case NeonTypeFlags::Int64: 584 if (IsInt64Long) 585 return Flags.isUnsigned() ? Context.UnsignedLongTy : Context.LongTy; 586 else 587 return Flags.isUnsigned() ? Context.UnsignedLongLongTy 588 : Context.LongLongTy; 589 case NeonTypeFlags::Poly8: 590 return IsPolyUnsigned ? Context.UnsignedCharTy : Context.SignedCharTy; 591 case NeonTypeFlags::Poly16: 592 return IsPolyUnsigned ? Context.UnsignedShortTy : Context.ShortTy; 593 case NeonTypeFlags::Poly64: 594 return Context.UnsignedLongTy; 595 case NeonTypeFlags::Poly128: 596 break; 597 case NeonTypeFlags::Float16: 598 return Context.HalfTy; 599 case NeonTypeFlags::Float32: 600 return Context.FloatTy; 601 case NeonTypeFlags::Float64: 602 return Context.DoubleTy; 603 } 604 llvm_unreachable("Invalid NeonTypeFlag!"); 605 } 606 607 bool Sema::CheckNeonBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) { 608 llvm::APSInt Result; 609 uint64_t mask = 0; 610 unsigned TV = 0; 611 int PtrArgNum = -1; 612 bool HasConstPtr = false; 613 switch (BuiltinID) { 614 #define GET_NEON_OVERLOAD_CHECK 615 #include "clang/Basic/arm_neon.inc" 616 #undef GET_NEON_OVERLOAD_CHECK 617 } 618 619 // For NEON intrinsics which are overloaded on vector element type, validate 620 // the immediate which specifies which variant to emit. 621 unsigned ImmArg = TheCall->getNumArgs()-1; 622 if (mask) { 623 if (SemaBuiltinConstantArg(TheCall, ImmArg, Result)) 624 return true; 625 626 TV = Result.getLimitedValue(64); 627 if ((TV > 63) || (mask & (1ULL << TV)) == 0) 628 return Diag(TheCall->getLocStart(), diag::err_invalid_neon_type_code) 629 << TheCall->getArg(ImmArg)->getSourceRange(); 630 } 631 632 if (PtrArgNum >= 0) { 633 // Check that pointer arguments have the specified type. 634 Expr *Arg = TheCall->getArg(PtrArgNum); 635 if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(Arg)) 636 Arg = ICE->getSubExpr(); 637 ExprResult RHS = DefaultFunctionArrayLvalueConversion(Arg); 638 QualType RHSTy = RHS.get()->getType(); 639 640 llvm::Triple::ArchType Arch = Context.getTargetInfo().getTriple().getArch(); 641 bool IsPolyUnsigned = Arch == llvm::Triple::aarch64; 642 bool IsInt64Long = 643 Context.getTargetInfo().getInt64Type() == TargetInfo::SignedLong; 644 QualType EltTy = 645 getNeonEltType(NeonTypeFlags(TV), Context, IsPolyUnsigned, IsInt64Long); 646 if (HasConstPtr) 647 EltTy = EltTy.withConst(); 648 QualType LHSTy = Context.getPointerType(EltTy); 649 AssignConvertType ConvTy; 650 ConvTy = CheckSingleAssignmentConstraints(LHSTy, RHS); 651 if (RHS.isInvalid()) 652 return true; 653 if (DiagnoseAssignmentResult(ConvTy, Arg->getLocStart(), LHSTy, RHSTy, 654 RHS.get(), AA_Assigning)) 655 return true; 656 } 657 658 // For NEON intrinsics which take an immediate value as part of the 659 // instruction, range check them here. 660 unsigned i = 0, l = 0, u = 0; 661 switch (BuiltinID) { 662 default: 663 return false; 664 #define GET_NEON_IMMEDIATE_CHECK 665 #include "clang/Basic/arm_neon.inc" 666 #undef GET_NEON_IMMEDIATE_CHECK 667 } 668 669 return SemaBuiltinConstantArgRange(TheCall, i, l, u + l); 670 } 671 672 bool Sema::CheckARMBuiltinExclusiveCall(unsigned BuiltinID, CallExpr *TheCall, 673 unsigned MaxWidth) { 674 assert((BuiltinID == ARM::BI__builtin_arm_ldrex || 675 BuiltinID == ARM::BI__builtin_arm_ldaex || 676 BuiltinID == ARM::BI__builtin_arm_strex || 677 BuiltinID == ARM::BI__builtin_arm_stlex || 678 BuiltinID == AArch64::BI__builtin_arm_ldrex || 679 BuiltinID == AArch64::BI__builtin_arm_ldaex || 680 BuiltinID == AArch64::BI__builtin_arm_strex || 681 BuiltinID == AArch64::BI__builtin_arm_stlex) && 682 "unexpected ARM builtin"); 683 bool IsLdrex = BuiltinID == ARM::BI__builtin_arm_ldrex || 684 BuiltinID == ARM::BI__builtin_arm_ldaex || 685 BuiltinID == AArch64::BI__builtin_arm_ldrex || 686 BuiltinID == AArch64::BI__builtin_arm_ldaex; 687 688 DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts()); 689 690 // Ensure that we have the proper number of arguments. 691 if (checkArgCount(*this, TheCall, IsLdrex ? 1 : 2)) 692 return true; 693 694 // Inspect the pointer argument of the atomic builtin. This should always be 695 // a pointer type, whose element is an integral scalar or pointer type. 696 // Because it is a pointer type, we don't have to worry about any implicit 697 // casts here. 698 Expr *PointerArg = TheCall->getArg(IsLdrex ? 0 : 1); 699 ExprResult PointerArgRes = DefaultFunctionArrayLvalueConversion(PointerArg); 700 if (PointerArgRes.isInvalid()) 701 return true; 702 PointerArg = PointerArgRes.get(); 703 704 const PointerType *pointerType = PointerArg->getType()->getAs<PointerType>(); 705 if (!pointerType) { 706 Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer) 707 << PointerArg->getType() << PointerArg->getSourceRange(); 708 return true; 709 } 710 711 // ldrex takes a "const volatile T*" and strex takes a "volatile T*". Our next 712 // task is to insert the appropriate casts into the AST. First work out just 713 // what the appropriate type is. 714 QualType ValType = pointerType->getPointeeType(); 715 QualType AddrType = ValType.getUnqualifiedType().withVolatile(); 716 if (IsLdrex) 717 AddrType.addConst(); 718 719 // Issue a warning if the cast is dodgy. 720 CastKind CastNeeded = CK_NoOp; 721 if (!AddrType.isAtLeastAsQualifiedAs(ValType)) { 722 CastNeeded = CK_BitCast; 723 Diag(DRE->getLocStart(), diag::ext_typecheck_convert_discards_qualifiers) 724 << PointerArg->getType() 725 << Context.getPointerType(AddrType) 726 << AA_Passing << PointerArg->getSourceRange(); 727 } 728 729 // Finally, do the cast and replace the argument with the corrected version. 730 AddrType = Context.getPointerType(AddrType); 731 PointerArgRes = ImpCastExprToType(PointerArg, AddrType, CastNeeded); 732 if (PointerArgRes.isInvalid()) 733 return true; 734 PointerArg = PointerArgRes.get(); 735 736 TheCall->setArg(IsLdrex ? 0 : 1, PointerArg); 737 738 // In general, we allow ints, floats and pointers to be loaded and stored. 739 if (!ValType->isIntegerType() && !ValType->isAnyPointerType() && 740 !ValType->isBlockPointerType() && !ValType->isFloatingType()) { 741 Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer_intfltptr) 742 << PointerArg->getType() << PointerArg->getSourceRange(); 743 return true; 744 } 745 746 // But ARM doesn't have instructions to deal with 128-bit versions. 747 if (Context.getTypeSize(ValType) > MaxWidth) { 748 assert(MaxWidth == 64 && "Diagnostic unexpectedly inaccurate"); 749 Diag(DRE->getLocStart(), diag::err_atomic_exclusive_builtin_pointer_size) 750 << PointerArg->getType() << PointerArg->getSourceRange(); 751 return true; 752 } 753 754 switch (ValType.getObjCLifetime()) { 755 case Qualifiers::OCL_None: 756 case Qualifiers::OCL_ExplicitNone: 757 // okay 758 break; 759 760 case Qualifiers::OCL_Weak: 761 case Qualifiers::OCL_Strong: 762 case Qualifiers::OCL_Autoreleasing: 763 Diag(DRE->getLocStart(), diag::err_arc_atomic_ownership) 764 << ValType << PointerArg->getSourceRange(); 765 return true; 766 } 767 768 769 if (IsLdrex) { 770 TheCall->setType(ValType); 771 return false; 772 } 773 774 // Initialize the argument to be stored. 775 ExprResult ValArg = TheCall->getArg(0); 776 InitializedEntity Entity = InitializedEntity::InitializeParameter( 777 Context, ValType, /*consume*/ false); 778 ValArg = PerformCopyInitialization(Entity, SourceLocation(), ValArg); 779 if (ValArg.isInvalid()) 780 return true; 781 TheCall->setArg(0, ValArg.get()); 782 783 // __builtin_arm_strex always returns an int. It's marked as such in the .def, 784 // but the custom checker bypasses all default analysis. 785 TheCall->setType(Context.IntTy); 786 return false; 787 } 788 789 bool Sema::CheckARMBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) { 790 llvm::APSInt Result; 791 792 if (BuiltinID == ARM::BI__builtin_arm_ldrex || 793 BuiltinID == ARM::BI__builtin_arm_ldaex || 794 BuiltinID == ARM::BI__builtin_arm_strex || 795 BuiltinID == ARM::BI__builtin_arm_stlex) { 796 return CheckARMBuiltinExclusiveCall(BuiltinID, TheCall, 64); 797 } 798 799 if (BuiltinID == ARM::BI__builtin_arm_prefetch) { 800 return SemaBuiltinConstantArgRange(TheCall, 1, 0, 1) || 801 SemaBuiltinConstantArgRange(TheCall, 2, 0, 1); 802 } 803 804 if (CheckNeonBuiltinFunctionCall(BuiltinID, TheCall)) 805 return true; 806 807 // For intrinsics which take an immediate value as part of the instruction, 808 // range check them here. 809 unsigned i = 0, l = 0, u = 0; 810 switch (BuiltinID) { 811 default: return false; 812 case ARM::BI__builtin_arm_ssat: i = 1; l = 1; u = 31; break; 813 case ARM::BI__builtin_arm_usat: i = 1; u = 31; break; 814 case ARM::BI__builtin_arm_vcvtr_f: 815 case ARM::BI__builtin_arm_vcvtr_d: i = 1; u = 1; break; 816 case ARM::BI__builtin_arm_dmb: 817 case ARM::BI__builtin_arm_dsb: 818 case ARM::BI__builtin_arm_isb: 819 case ARM::BI__builtin_arm_dbg: l = 0; u = 15; break; 820 } 821 822 // FIXME: VFP Intrinsics should error if VFP not present. 823 return SemaBuiltinConstantArgRange(TheCall, i, l, u + l); 824 } 825 826 bool Sema::CheckAArch64BuiltinFunctionCall(unsigned BuiltinID, 827 CallExpr *TheCall) { 828 llvm::APSInt Result; 829 830 if (BuiltinID == AArch64::BI__builtin_arm_ldrex || 831 BuiltinID == AArch64::BI__builtin_arm_ldaex || 832 BuiltinID == AArch64::BI__builtin_arm_strex || 833 BuiltinID == AArch64::BI__builtin_arm_stlex) { 834 return CheckARMBuiltinExclusiveCall(BuiltinID, TheCall, 128); 835 } 836 837 if (BuiltinID == AArch64::BI__builtin_arm_prefetch) { 838 return SemaBuiltinConstantArgRange(TheCall, 1, 0, 1) || 839 SemaBuiltinConstantArgRange(TheCall, 2, 0, 2) || 840 SemaBuiltinConstantArgRange(TheCall, 3, 0, 1) || 841 SemaBuiltinConstantArgRange(TheCall, 4, 0, 1); 842 } 843 844 if (CheckNeonBuiltinFunctionCall(BuiltinID, TheCall)) 845 return true; 846 847 // For intrinsics which take an immediate value as part of the instruction, 848 // range check them here. 849 unsigned i = 0, l = 0, u = 0; 850 switch (BuiltinID) { 851 default: return false; 852 case AArch64::BI__builtin_arm_dmb: 853 case AArch64::BI__builtin_arm_dsb: 854 case AArch64::BI__builtin_arm_isb: l = 0; u = 15; break; 855 } 856 857 return SemaBuiltinConstantArgRange(TheCall, i, l, u + l); 858 } 859 860 bool Sema::CheckMipsBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) { 861 unsigned i = 0, l = 0, u = 0; 862 switch (BuiltinID) { 863 default: return false; 864 case Mips::BI__builtin_mips_wrdsp: i = 1; l = 0; u = 63; break; 865 case Mips::BI__builtin_mips_rddsp: i = 0; l = 0; u = 63; break; 866 case Mips::BI__builtin_mips_append: i = 2; l = 0; u = 31; break; 867 case Mips::BI__builtin_mips_balign: i = 2; l = 0; u = 3; break; 868 case Mips::BI__builtin_mips_precr_sra_ph_w: i = 2; l = 0; u = 31; break; 869 case Mips::BI__builtin_mips_precr_sra_r_ph_w: i = 2; l = 0; u = 31; break; 870 case Mips::BI__builtin_mips_prepend: i = 2; l = 0; u = 31; break; 871 } 872 873 return SemaBuiltinConstantArgRange(TheCall, i, l, u); 874 } 875 876 bool Sema::CheckX86BuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) { 877 unsigned i = 0, l = 0, u = 0; 878 switch (BuiltinID) { 879 default: return false; 880 case X86::BI_mm_prefetch: i = 1; l = 0; u = 3; break; 881 case X86::BI__builtin_ia32_vextractf128_pd256: 882 case X86::BI__builtin_ia32_vextractf128_ps256: 883 case X86::BI__builtin_ia32_vextractf128_si256: 884 case X86::BI__builtin_ia32_extract128i256: i = 1, l = 0, u = 1; break; 885 case X86::BI__builtin_ia32_vinsertf128_pd256: 886 case X86::BI__builtin_ia32_vinsertf128_ps256: 887 case X86::BI__builtin_ia32_vinsertf128_si256: 888 case X86::BI__builtin_ia32_insert128i256: 889 case X86::BI__builtin_ia32_blendpd: i = 2, l = 0; u = 1; break; 890 case X86::BI__builtin_ia32_blendps: 891 case X86::BI__builtin_ia32_blendpd256: 892 case X86::BI__builtin_ia32_sha1rnds4: i = 2, l = 0; u = 3; break; 893 case X86::BI__builtin_ia32_vpermil2pd: 894 case X86::BI__builtin_ia32_vpermil2pd256: 895 case X86::BI__builtin_ia32_vpermil2ps: 896 case X86::BI__builtin_ia32_vpermil2ps256: i = 3, l = 0; u = 3; break; 897 case X86::BI__builtin_ia32_cmpb128_mask: 898 case X86::BI__builtin_ia32_cmpw128_mask: 899 case X86::BI__builtin_ia32_cmpd128_mask: 900 case X86::BI__builtin_ia32_cmpq128_mask: 901 case X86::BI__builtin_ia32_cmpb256_mask: 902 case X86::BI__builtin_ia32_cmpw256_mask: 903 case X86::BI__builtin_ia32_cmpd256_mask: 904 case X86::BI__builtin_ia32_cmpq256_mask: 905 case X86::BI__builtin_ia32_cmpb512_mask: 906 case X86::BI__builtin_ia32_cmpw512_mask: 907 case X86::BI__builtin_ia32_cmpd512_mask: 908 case X86::BI__builtin_ia32_cmpq512_mask: 909 case X86::BI__builtin_ia32_ucmpb128_mask: 910 case X86::BI__builtin_ia32_ucmpw128_mask: 911 case X86::BI__builtin_ia32_ucmpd128_mask: 912 case X86::BI__builtin_ia32_ucmpq128_mask: 913 case X86::BI__builtin_ia32_ucmpb256_mask: 914 case X86::BI__builtin_ia32_ucmpw256_mask: 915 case X86::BI__builtin_ia32_ucmpd256_mask: 916 case X86::BI__builtin_ia32_ucmpq256_mask: 917 case X86::BI__builtin_ia32_ucmpb512_mask: 918 case X86::BI__builtin_ia32_ucmpw512_mask: 919 case X86::BI__builtin_ia32_ucmpd512_mask: 920 case X86::BI__builtin_ia32_ucmpq512_mask: i = 2; l = 0; u = 7; break; 921 case X86::BI__builtin_ia32_roundps: 922 case X86::BI__builtin_ia32_roundpd: 923 case X86::BI__builtin_ia32_roundps256: 924 case X86::BI__builtin_ia32_roundpd256: i = 1, l = 0; u = 15; break; 925 case X86::BI__builtin_ia32_roundss: 926 case X86::BI__builtin_ia32_roundsd: i = 2, l = 0; u = 15; break; 927 case X86::BI__builtin_ia32_cmpps: 928 case X86::BI__builtin_ia32_cmpss: 929 case X86::BI__builtin_ia32_cmppd: 930 case X86::BI__builtin_ia32_cmpsd: 931 case X86::BI__builtin_ia32_cmpps256: 932 case X86::BI__builtin_ia32_cmppd256: 933 case X86::BI__builtin_ia32_cmpps512_mask: 934 case X86::BI__builtin_ia32_cmppd512_mask: i = 2; l = 0; u = 31; break; 935 case X86::BI__builtin_ia32_vpcomub: 936 case X86::BI__builtin_ia32_vpcomuw: 937 case X86::BI__builtin_ia32_vpcomud: 938 case X86::BI__builtin_ia32_vpcomuq: 939 case X86::BI__builtin_ia32_vpcomb: 940 case X86::BI__builtin_ia32_vpcomw: 941 case X86::BI__builtin_ia32_vpcomd: 942 case X86::BI__builtin_ia32_vpcomq: i = 2; l = 0; u = 7; break; 943 } 944 return SemaBuiltinConstantArgRange(TheCall, i, l, u); 945 } 946 947 /// Given a FunctionDecl's FormatAttr, attempts to populate the FomatStringInfo 948 /// parameter with the FormatAttr's correct format_idx and firstDataArg. 949 /// Returns true when the format fits the function and the FormatStringInfo has 950 /// been populated. 951 bool Sema::getFormatStringInfo(const FormatAttr *Format, bool IsCXXMember, 952 FormatStringInfo *FSI) { 953 FSI->HasVAListArg = Format->getFirstArg() == 0; 954 FSI->FormatIdx = Format->getFormatIdx() - 1; 955 FSI->FirstDataArg = FSI->HasVAListArg ? 0 : Format->getFirstArg() - 1; 956 957 // The way the format attribute works in GCC, the implicit this argument 958 // of member functions is counted. However, it doesn't appear in our own 959 // lists, so decrement format_idx in that case. 960 if (IsCXXMember) { 961 if(FSI->FormatIdx == 0) 962 return false; 963 --FSI->FormatIdx; 964 if (FSI->FirstDataArg != 0) 965 --FSI->FirstDataArg; 966 } 967 return true; 968 } 969 970 /// Checks if a the given expression evaluates to null. 971 /// 972 /// \brief Returns true if the value evaluates to null. 973 static bool CheckNonNullExpr(Sema &S, 974 const Expr *Expr) { 975 // As a special case, transparent unions initialized with zero are 976 // considered null for the purposes of the nonnull attribute. 977 if (const RecordType *UT = Expr->getType()->getAsUnionType()) { 978 if (UT->getDecl()->hasAttr<TransparentUnionAttr>()) 979 if (const CompoundLiteralExpr *CLE = 980 dyn_cast<CompoundLiteralExpr>(Expr)) 981 if (const InitListExpr *ILE = 982 dyn_cast<InitListExpr>(CLE->getInitializer())) 983 Expr = ILE->getInit(0); 984 } 985 986 bool Result; 987 return (!Expr->isValueDependent() && 988 Expr->EvaluateAsBooleanCondition(Result, S.Context) && 989 !Result); 990 } 991 992 static void CheckNonNullArgument(Sema &S, 993 const Expr *ArgExpr, 994 SourceLocation CallSiteLoc) { 995 if (CheckNonNullExpr(S, ArgExpr)) 996 S.Diag(CallSiteLoc, diag::warn_null_arg) << ArgExpr->getSourceRange(); 997 } 998 999 bool Sema::GetFormatNSStringIdx(const FormatAttr *Format, unsigned &Idx) { 1000 FormatStringInfo FSI; 1001 if ((GetFormatStringType(Format) == FST_NSString) && 1002 getFormatStringInfo(Format, false, &FSI)) { 1003 Idx = FSI.FormatIdx; 1004 return true; 1005 } 1006 return false; 1007 } 1008 /// \brief Diagnose use of %s directive in an NSString which is being passed 1009 /// as formatting string to formatting method. 1010 static void 1011 DiagnoseCStringFormatDirectiveInCFAPI(Sema &S, 1012 const NamedDecl *FDecl, 1013 Expr **Args, 1014 unsigned NumArgs) { 1015 unsigned Idx = 0; 1016 bool Format = false; 1017 ObjCStringFormatFamily SFFamily = FDecl->getObjCFStringFormattingFamily(); 1018 if (SFFamily == ObjCStringFormatFamily::SFF_CFString) { 1019 Idx = 2; 1020 Format = true; 1021 } 1022 else 1023 for (const auto *I : FDecl->specific_attrs<FormatAttr>()) { 1024 if (S.GetFormatNSStringIdx(I, Idx)) { 1025 Format = true; 1026 break; 1027 } 1028 } 1029 if (!Format || NumArgs <= Idx) 1030 return; 1031 const Expr *FormatExpr = Args[Idx]; 1032 if (const CStyleCastExpr *CSCE = dyn_cast<CStyleCastExpr>(FormatExpr)) 1033 FormatExpr = CSCE->getSubExpr(); 1034 const StringLiteral *FormatString; 1035 if (const ObjCStringLiteral *OSL = 1036 dyn_cast<ObjCStringLiteral>(FormatExpr->IgnoreParenImpCasts())) 1037 FormatString = OSL->getString(); 1038 else 1039 FormatString = dyn_cast<StringLiteral>(FormatExpr->IgnoreParenImpCasts()); 1040 if (!FormatString) 1041 return; 1042 if (S.FormatStringHasSArg(FormatString)) { 1043 S.Diag(FormatExpr->getExprLoc(), diag::warn_objc_cdirective_format_string) 1044 << "%s" << 1 << 1; 1045 S.Diag(FDecl->getLocation(), diag::note_entity_declared_at) 1046 << FDecl->getDeclName(); 1047 } 1048 } 1049 1050 static void CheckNonNullArguments(Sema &S, 1051 const NamedDecl *FDecl, 1052 ArrayRef<const Expr *> Args, 1053 SourceLocation CallSiteLoc) { 1054 // Check the attributes attached to the method/function itself. 1055 llvm::SmallBitVector NonNullArgs; 1056 for (const auto *NonNull : FDecl->specific_attrs<NonNullAttr>()) { 1057 if (!NonNull->args_size()) { 1058 // Easy case: all pointer arguments are nonnull. 1059 for (const auto *Arg : Args) 1060 if (S.isValidPointerAttrType(Arg->getType())) 1061 CheckNonNullArgument(S, Arg, CallSiteLoc); 1062 return; 1063 } 1064 1065 for (unsigned Val : NonNull->args()) { 1066 if (Val >= Args.size()) 1067 continue; 1068 if (NonNullArgs.empty()) 1069 NonNullArgs.resize(Args.size()); 1070 NonNullArgs.set(Val); 1071 } 1072 } 1073 1074 // Check the attributes on the parameters. 1075 ArrayRef<ParmVarDecl*> parms; 1076 if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(FDecl)) 1077 parms = FD->parameters(); 1078 else if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(FDecl)) 1079 parms = MD->parameters(); 1080 1081 unsigned ArgIndex = 0; 1082 for (ArrayRef<ParmVarDecl*>::iterator I = parms.begin(), E = parms.end(); 1083 I != E; ++I, ++ArgIndex) { 1084 const ParmVarDecl *PVD = *I; 1085 if (PVD->hasAttr<NonNullAttr>() || 1086 (ArgIndex < NonNullArgs.size() && NonNullArgs[ArgIndex])) 1087 CheckNonNullArgument(S, Args[ArgIndex], CallSiteLoc); 1088 } 1089 1090 // In case this is a variadic call, check any remaining arguments. 1091 for (/**/; ArgIndex < NonNullArgs.size(); ++ArgIndex) 1092 if (NonNullArgs[ArgIndex]) 1093 CheckNonNullArgument(S, Args[ArgIndex], CallSiteLoc); 1094 } 1095 1096 /// Handles the checks for format strings, non-POD arguments to vararg 1097 /// functions, and NULL arguments passed to non-NULL parameters. 1098 void Sema::checkCall(NamedDecl *FDecl, ArrayRef<const Expr *> Args, 1099 unsigned NumParams, bool IsMemberFunction, 1100 SourceLocation Loc, SourceRange Range, 1101 VariadicCallType CallType) { 1102 // FIXME: We should check as much as we can in the template definition. 1103 if (CurContext->isDependentContext()) 1104 return; 1105 1106 // Printf and scanf checking. 1107 llvm::SmallBitVector CheckedVarArgs; 1108 if (FDecl) { 1109 for (const auto *I : FDecl->specific_attrs<FormatAttr>()) { 1110 // Only create vector if there are format attributes. 1111 CheckedVarArgs.resize(Args.size()); 1112 1113 CheckFormatArguments(I, Args, IsMemberFunction, CallType, Loc, Range, 1114 CheckedVarArgs); 1115 } 1116 } 1117 1118 // Refuse POD arguments that weren't caught by the format string 1119 // checks above. 1120 if (CallType != VariadicDoesNotApply) { 1121 for (unsigned ArgIdx = NumParams; ArgIdx < Args.size(); ++ArgIdx) { 1122 // Args[ArgIdx] can be null in malformed code. 1123 if (const Expr *Arg = Args[ArgIdx]) { 1124 if (CheckedVarArgs.empty() || !CheckedVarArgs[ArgIdx]) 1125 checkVariadicArgument(Arg, CallType); 1126 } 1127 } 1128 } 1129 1130 if (FDecl) { 1131 CheckNonNullArguments(*this, FDecl, Args, Loc); 1132 1133 // Type safety checking. 1134 for (const auto *I : FDecl->specific_attrs<ArgumentWithTypeTagAttr>()) 1135 CheckArgumentWithTypeTag(I, Args.data()); 1136 } 1137 } 1138 1139 /// CheckConstructorCall - Check a constructor call for correctness and safety 1140 /// properties not enforced by the C type system. 1141 void Sema::CheckConstructorCall(FunctionDecl *FDecl, 1142 ArrayRef<const Expr *> Args, 1143 const FunctionProtoType *Proto, 1144 SourceLocation Loc) { 1145 VariadicCallType CallType = 1146 Proto->isVariadic() ? VariadicConstructor : VariadicDoesNotApply; 1147 checkCall(FDecl, Args, Proto->getNumParams(), 1148 /*IsMemberFunction=*/true, Loc, SourceRange(), CallType); 1149 } 1150 1151 /// CheckFunctionCall - Check a direct function call for various correctness 1152 /// and safety properties not strictly enforced by the C type system. 1153 bool Sema::CheckFunctionCall(FunctionDecl *FDecl, CallExpr *TheCall, 1154 const FunctionProtoType *Proto) { 1155 bool IsMemberOperatorCall = isa<CXXOperatorCallExpr>(TheCall) && 1156 isa<CXXMethodDecl>(FDecl); 1157 bool IsMemberFunction = isa<CXXMemberCallExpr>(TheCall) || 1158 IsMemberOperatorCall; 1159 VariadicCallType CallType = getVariadicCallType(FDecl, Proto, 1160 TheCall->getCallee()); 1161 unsigned NumParams = Proto ? Proto->getNumParams() : 0; 1162 Expr** Args = TheCall->getArgs(); 1163 unsigned NumArgs = TheCall->getNumArgs(); 1164 if (IsMemberOperatorCall) { 1165 // If this is a call to a member operator, hide the first argument 1166 // from checkCall. 1167 // FIXME: Our choice of AST representation here is less than ideal. 1168 ++Args; 1169 --NumArgs; 1170 } 1171 checkCall(FDecl, llvm::makeArrayRef(Args, NumArgs), NumParams, 1172 IsMemberFunction, TheCall->getRParenLoc(), 1173 TheCall->getCallee()->getSourceRange(), CallType); 1174 1175 IdentifierInfo *FnInfo = FDecl->getIdentifier(); 1176 // None of the checks below are needed for functions that don't have 1177 // simple names (e.g., C++ conversion functions). 1178 if (!FnInfo) 1179 return false; 1180 1181 CheckAbsoluteValueFunction(TheCall, FDecl, FnInfo); 1182 if (getLangOpts().ObjC1) 1183 DiagnoseCStringFormatDirectiveInCFAPI(*this, FDecl, Args, NumArgs); 1184 1185 unsigned CMId = FDecl->getMemoryFunctionKind(); 1186 if (CMId == 0) 1187 return false; 1188 1189 // Handle memory setting and copying functions. 1190 if (CMId == Builtin::BIstrlcpy || CMId == Builtin::BIstrlcat) 1191 CheckStrlcpycatArguments(TheCall, FnInfo); 1192 else if (CMId == Builtin::BIstrncat) 1193 CheckStrncatArguments(TheCall, FnInfo); 1194 else 1195 CheckMemaccessArguments(TheCall, CMId, FnInfo); 1196 1197 return false; 1198 } 1199 1200 bool Sema::CheckObjCMethodCall(ObjCMethodDecl *Method, SourceLocation lbrac, 1201 ArrayRef<const Expr *> Args) { 1202 VariadicCallType CallType = 1203 Method->isVariadic() ? VariadicMethod : VariadicDoesNotApply; 1204 1205 checkCall(Method, Args, Method->param_size(), 1206 /*IsMemberFunction=*/false, 1207 lbrac, Method->getSourceRange(), CallType); 1208 1209 return false; 1210 } 1211 1212 bool Sema::CheckPointerCall(NamedDecl *NDecl, CallExpr *TheCall, 1213 const FunctionProtoType *Proto) { 1214 const VarDecl *V = dyn_cast<VarDecl>(NDecl); 1215 if (!V) 1216 return false; 1217 1218 QualType Ty = V->getType(); 1219 if (!Ty->isBlockPointerType() && !Ty->isFunctionPointerType()) 1220 return false; 1221 1222 VariadicCallType CallType; 1223 if (!Proto || !Proto->isVariadic()) { 1224 CallType = VariadicDoesNotApply; 1225 } else if (Ty->isBlockPointerType()) { 1226 CallType = VariadicBlock; 1227 } else { // Ty->isFunctionPointerType() 1228 CallType = VariadicFunction; 1229 } 1230 unsigned NumParams = Proto ? Proto->getNumParams() : 0; 1231 1232 checkCall(NDecl, llvm::makeArrayRef(TheCall->getArgs(), 1233 TheCall->getNumArgs()), 1234 NumParams, /*IsMemberFunction=*/false, TheCall->getRParenLoc(), 1235 TheCall->getCallee()->getSourceRange(), CallType); 1236 1237 return false; 1238 } 1239 1240 /// Checks function calls when a FunctionDecl or a NamedDecl is not available, 1241 /// such as function pointers returned from functions. 1242 bool Sema::CheckOtherCall(CallExpr *TheCall, const FunctionProtoType *Proto) { 1243 VariadicCallType CallType = getVariadicCallType(/*FDecl=*/nullptr, Proto, 1244 TheCall->getCallee()); 1245 unsigned NumParams = Proto ? Proto->getNumParams() : 0; 1246 1247 checkCall(/*FDecl=*/nullptr, 1248 llvm::makeArrayRef(TheCall->getArgs(), TheCall->getNumArgs()), 1249 NumParams, /*IsMemberFunction=*/false, TheCall->getRParenLoc(), 1250 TheCall->getCallee()->getSourceRange(), CallType); 1251 1252 return false; 1253 } 1254 1255 static bool isValidOrderingForOp(int64_t Ordering, AtomicExpr::AtomicOp Op) { 1256 if (Ordering < AtomicExpr::AO_ABI_memory_order_relaxed || 1257 Ordering > AtomicExpr::AO_ABI_memory_order_seq_cst) 1258 return false; 1259 1260 switch (Op) { 1261 case AtomicExpr::AO__c11_atomic_init: 1262 llvm_unreachable("There is no ordering argument for an init"); 1263 1264 case AtomicExpr::AO__c11_atomic_load: 1265 case AtomicExpr::AO__atomic_load_n: 1266 case AtomicExpr::AO__atomic_load: 1267 return Ordering != AtomicExpr::AO_ABI_memory_order_release && 1268 Ordering != AtomicExpr::AO_ABI_memory_order_acq_rel; 1269 1270 case AtomicExpr::AO__c11_atomic_store: 1271 case AtomicExpr::AO__atomic_store: 1272 case AtomicExpr::AO__atomic_store_n: 1273 return Ordering != AtomicExpr::AO_ABI_memory_order_consume && 1274 Ordering != AtomicExpr::AO_ABI_memory_order_acquire && 1275 Ordering != AtomicExpr::AO_ABI_memory_order_acq_rel; 1276 1277 default: 1278 return true; 1279 } 1280 } 1281 1282 ExprResult Sema::SemaAtomicOpsOverloaded(ExprResult TheCallResult, 1283 AtomicExpr::AtomicOp Op) { 1284 CallExpr *TheCall = cast<CallExpr>(TheCallResult.get()); 1285 DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts()); 1286 1287 // All these operations take one of the following forms: 1288 enum { 1289 // C __c11_atomic_init(A *, C) 1290 Init, 1291 // C __c11_atomic_load(A *, int) 1292 Load, 1293 // void __atomic_load(A *, CP, int) 1294 Copy, 1295 // C __c11_atomic_add(A *, M, int) 1296 Arithmetic, 1297 // C __atomic_exchange_n(A *, CP, int) 1298 Xchg, 1299 // void __atomic_exchange(A *, C *, CP, int) 1300 GNUXchg, 1301 // bool __c11_atomic_compare_exchange_strong(A *, C *, CP, int, int) 1302 C11CmpXchg, 1303 // bool __atomic_compare_exchange(A *, C *, CP, bool, int, int) 1304 GNUCmpXchg 1305 } Form = Init; 1306 const unsigned NumArgs[] = { 2, 2, 3, 3, 3, 4, 5, 6 }; 1307 const unsigned NumVals[] = { 1, 0, 1, 1, 1, 2, 2, 3 }; 1308 // where: 1309 // C is an appropriate type, 1310 // A is volatile _Atomic(C) for __c11 builtins and is C for GNU builtins, 1311 // CP is C for __c11 builtins and GNU _n builtins and is C * otherwise, 1312 // M is C if C is an integer, and ptrdiff_t if C is a pointer, and 1313 // the int parameters are for orderings. 1314 1315 assert(AtomicExpr::AO__c11_atomic_init == 0 && 1316 AtomicExpr::AO__c11_atomic_fetch_xor + 1 == AtomicExpr::AO__atomic_load 1317 && "need to update code for modified C11 atomics"); 1318 bool IsC11 = Op >= AtomicExpr::AO__c11_atomic_init && 1319 Op <= AtomicExpr::AO__c11_atomic_fetch_xor; 1320 bool IsN = Op == AtomicExpr::AO__atomic_load_n || 1321 Op == AtomicExpr::AO__atomic_store_n || 1322 Op == AtomicExpr::AO__atomic_exchange_n || 1323 Op == AtomicExpr::AO__atomic_compare_exchange_n; 1324 bool IsAddSub = false; 1325 1326 switch (Op) { 1327 case AtomicExpr::AO__c11_atomic_init: 1328 Form = Init; 1329 break; 1330 1331 case AtomicExpr::AO__c11_atomic_load: 1332 case AtomicExpr::AO__atomic_load_n: 1333 Form = Load; 1334 break; 1335 1336 case AtomicExpr::AO__c11_atomic_store: 1337 case AtomicExpr::AO__atomic_load: 1338 case AtomicExpr::AO__atomic_store: 1339 case AtomicExpr::AO__atomic_store_n: 1340 Form = Copy; 1341 break; 1342 1343 case AtomicExpr::AO__c11_atomic_fetch_add: 1344 case AtomicExpr::AO__c11_atomic_fetch_sub: 1345 case AtomicExpr::AO__atomic_fetch_add: 1346 case AtomicExpr::AO__atomic_fetch_sub: 1347 case AtomicExpr::AO__atomic_add_fetch: 1348 case AtomicExpr::AO__atomic_sub_fetch: 1349 IsAddSub = true; 1350 // Fall through. 1351 case AtomicExpr::AO__c11_atomic_fetch_and: 1352 case AtomicExpr::AO__c11_atomic_fetch_or: 1353 case AtomicExpr::AO__c11_atomic_fetch_xor: 1354 case AtomicExpr::AO__atomic_fetch_and: 1355 case AtomicExpr::AO__atomic_fetch_or: 1356 case AtomicExpr::AO__atomic_fetch_xor: 1357 case AtomicExpr::AO__atomic_fetch_nand: 1358 case AtomicExpr::AO__atomic_and_fetch: 1359 case AtomicExpr::AO__atomic_or_fetch: 1360 case AtomicExpr::AO__atomic_xor_fetch: 1361 case AtomicExpr::AO__atomic_nand_fetch: 1362 Form = Arithmetic; 1363 break; 1364 1365 case AtomicExpr::AO__c11_atomic_exchange: 1366 case AtomicExpr::AO__atomic_exchange_n: 1367 Form = Xchg; 1368 break; 1369 1370 case AtomicExpr::AO__atomic_exchange: 1371 Form = GNUXchg; 1372 break; 1373 1374 case AtomicExpr::AO__c11_atomic_compare_exchange_strong: 1375 case AtomicExpr::AO__c11_atomic_compare_exchange_weak: 1376 Form = C11CmpXchg; 1377 break; 1378 1379 case AtomicExpr::AO__atomic_compare_exchange: 1380 case AtomicExpr::AO__atomic_compare_exchange_n: 1381 Form = GNUCmpXchg; 1382 break; 1383 } 1384 1385 // Check we have the right number of arguments. 1386 if (TheCall->getNumArgs() < NumArgs[Form]) { 1387 Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args) 1388 << 0 << NumArgs[Form] << TheCall->getNumArgs() 1389 << TheCall->getCallee()->getSourceRange(); 1390 return ExprError(); 1391 } else if (TheCall->getNumArgs() > NumArgs[Form]) { 1392 Diag(TheCall->getArg(NumArgs[Form])->getLocStart(), 1393 diag::err_typecheck_call_too_many_args) 1394 << 0 << NumArgs[Form] << TheCall->getNumArgs() 1395 << TheCall->getCallee()->getSourceRange(); 1396 return ExprError(); 1397 } 1398 1399 // Inspect the first argument of the atomic operation. 1400 Expr *Ptr = TheCall->getArg(0); 1401 Ptr = DefaultFunctionArrayLvalueConversion(Ptr).get(); 1402 const PointerType *pointerType = Ptr->getType()->getAs<PointerType>(); 1403 if (!pointerType) { 1404 Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer) 1405 << Ptr->getType() << Ptr->getSourceRange(); 1406 return ExprError(); 1407 } 1408 1409 // For a __c11 builtin, this should be a pointer to an _Atomic type. 1410 QualType AtomTy = pointerType->getPointeeType(); // 'A' 1411 QualType ValType = AtomTy; // 'C' 1412 if (IsC11) { 1413 if (!AtomTy->isAtomicType()) { 1414 Diag(DRE->getLocStart(), diag::err_atomic_op_needs_atomic) 1415 << Ptr->getType() << Ptr->getSourceRange(); 1416 return ExprError(); 1417 } 1418 if (AtomTy.isConstQualified()) { 1419 Diag(DRE->getLocStart(), diag::err_atomic_op_needs_non_const_atomic) 1420 << Ptr->getType() << Ptr->getSourceRange(); 1421 return ExprError(); 1422 } 1423 ValType = AtomTy->getAs<AtomicType>()->getValueType(); 1424 } 1425 1426 // For an arithmetic operation, the implied arithmetic must be well-formed. 1427 if (Form == Arithmetic) { 1428 // gcc does not enforce these rules for GNU atomics, but we do so for sanity. 1429 if (IsAddSub && !ValType->isIntegerType() && !ValType->isPointerType()) { 1430 Diag(DRE->getLocStart(), diag::err_atomic_op_needs_atomic_int_or_ptr) 1431 << IsC11 << Ptr->getType() << Ptr->getSourceRange(); 1432 return ExprError(); 1433 } 1434 if (!IsAddSub && !ValType->isIntegerType()) { 1435 Diag(DRE->getLocStart(), diag::err_atomic_op_bitwise_needs_atomic_int) 1436 << IsC11 << Ptr->getType() << Ptr->getSourceRange(); 1437 return ExprError(); 1438 } 1439 if (IsC11 && ValType->isPointerType() && 1440 RequireCompleteType(Ptr->getLocStart(), ValType->getPointeeType(), 1441 diag::err_incomplete_type)) { 1442 return ExprError(); 1443 } 1444 } else if (IsN && !ValType->isIntegerType() && !ValType->isPointerType()) { 1445 // For __atomic_*_n operations, the value type must be a scalar integral or 1446 // pointer type which is 1, 2, 4, 8 or 16 bytes in length. 1447 Diag(DRE->getLocStart(), diag::err_atomic_op_needs_atomic_int_or_ptr) 1448 << IsC11 << Ptr->getType() << Ptr->getSourceRange(); 1449 return ExprError(); 1450 } 1451 1452 if (!IsC11 && !AtomTy.isTriviallyCopyableType(Context) && 1453 !AtomTy->isScalarType()) { 1454 // For GNU atomics, require a trivially-copyable type. This is not part of 1455 // the GNU atomics specification, but we enforce it for sanity. 1456 Diag(DRE->getLocStart(), diag::err_atomic_op_needs_trivial_copy) 1457 << Ptr->getType() << Ptr->getSourceRange(); 1458 return ExprError(); 1459 } 1460 1461 // FIXME: For any builtin other than a load, the ValType must not be 1462 // const-qualified. 1463 1464 switch (ValType.getObjCLifetime()) { 1465 case Qualifiers::OCL_None: 1466 case Qualifiers::OCL_ExplicitNone: 1467 // okay 1468 break; 1469 1470 case Qualifiers::OCL_Weak: 1471 case Qualifiers::OCL_Strong: 1472 case Qualifiers::OCL_Autoreleasing: 1473 // FIXME: Can this happen? By this point, ValType should be known 1474 // to be trivially copyable. 1475 Diag(DRE->getLocStart(), diag::err_arc_atomic_ownership) 1476 << ValType << Ptr->getSourceRange(); 1477 return ExprError(); 1478 } 1479 1480 QualType ResultType = ValType; 1481 if (Form == Copy || Form == GNUXchg || Form == Init) 1482 ResultType = Context.VoidTy; 1483 else if (Form == C11CmpXchg || Form == GNUCmpXchg) 1484 ResultType = Context.BoolTy; 1485 1486 // The type of a parameter passed 'by value'. In the GNU atomics, such 1487 // arguments are actually passed as pointers. 1488 QualType ByValType = ValType; // 'CP' 1489 if (!IsC11 && !IsN) 1490 ByValType = Ptr->getType(); 1491 1492 // The first argument --- the pointer --- has a fixed type; we 1493 // deduce the types of the rest of the arguments accordingly. Walk 1494 // the remaining arguments, converting them to the deduced value type. 1495 for (unsigned i = 1; i != NumArgs[Form]; ++i) { 1496 QualType Ty; 1497 if (i < NumVals[Form] + 1) { 1498 switch (i) { 1499 case 1: 1500 // The second argument is the non-atomic operand. For arithmetic, this 1501 // is always passed by value, and for a compare_exchange it is always 1502 // passed by address. For the rest, GNU uses by-address and C11 uses 1503 // by-value. 1504 assert(Form != Load); 1505 if (Form == Init || (Form == Arithmetic && ValType->isIntegerType())) 1506 Ty = ValType; 1507 else if (Form == Copy || Form == Xchg) 1508 Ty = ByValType; 1509 else if (Form == Arithmetic) 1510 Ty = Context.getPointerDiffType(); 1511 else 1512 Ty = Context.getPointerType(ValType.getUnqualifiedType()); 1513 break; 1514 case 2: 1515 // The third argument to compare_exchange / GNU exchange is a 1516 // (pointer to a) desired value. 1517 Ty = ByValType; 1518 break; 1519 case 3: 1520 // The fourth argument to GNU compare_exchange is a 'weak' flag. 1521 Ty = Context.BoolTy; 1522 break; 1523 } 1524 } else { 1525 // The order(s) are always converted to int. 1526 Ty = Context.IntTy; 1527 } 1528 1529 InitializedEntity Entity = 1530 InitializedEntity::InitializeParameter(Context, Ty, false); 1531 ExprResult Arg = TheCall->getArg(i); 1532 Arg = PerformCopyInitialization(Entity, SourceLocation(), Arg); 1533 if (Arg.isInvalid()) 1534 return true; 1535 TheCall->setArg(i, Arg.get()); 1536 } 1537 1538 // Permute the arguments into a 'consistent' order. 1539 SmallVector<Expr*, 5> SubExprs; 1540 SubExprs.push_back(Ptr); 1541 switch (Form) { 1542 case Init: 1543 // Note, AtomicExpr::getVal1() has a special case for this atomic. 1544 SubExprs.push_back(TheCall->getArg(1)); // Val1 1545 break; 1546 case Load: 1547 SubExprs.push_back(TheCall->getArg(1)); // Order 1548 break; 1549 case Copy: 1550 case Arithmetic: 1551 case Xchg: 1552 SubExprs.push_back(TheCall->getArg(2)); // Order 1553 SubExprs.push_back(TheCall->getArg(1)); // Val1 1554 break; 1555 case GNUXchg: 1556 // Note, AtomicExpr::getVal2() has a special case for this atomic. 1557 SubExprs.push_back(TheCall->getArg(3)); // Order 1558 SubExprs.push_back(TheCall->getArg(1)); // Val1 1559 SubExprs.push_back(TheCall->getArg(2)); // Val2 1560 break; 1561 case C11CmpXchg: 1562 SubExprs.push_back(TheCall->getArg(3)); // Order 1563 SubExprs.push_back(TheCall->getArg(1)); // Val1 1564 SubExprs.push_back(TheCall->getArg(4)); // OrderFail 1565 SubExprs.push_back(TheCall->getArg(2)); // Val2 1566 break; 1567 case GNUCmpXchg: 1568 SubExprs.push_back(TheCall->getArg(4)); // Order 1569 SubExprs.push_back(TheCall->getArg(1)); // Val1 1570 SubExprs.push_back(TheCall->getArg(5)); // OrderFail 1571 SubExprs.push_back(TheCall->getArg(2)); // Val2 1572 SubExprs.push_back(TheCall->getArg(3)); // Weak 1573 break; 1574 } 1575 1576 if (SubExprs.size() >= 2 && Form != Init) { 1577 llvm::APSInt Result(32); 1578 if (SubExprs[1]->isIntegerConstantExpr(Result, Context) && 1579 !isValidOrderingForOp(Result.getSExtValue(), Op)) 1580 Diag(SubExprs[1]->getLocStart(), 1581 diag::warn_atomic_op_has_invalid_memory_order) 1582 << SubExprs[1]->getSourceRange(); 1583 } 1584 1585 AtomicExpr *AE = new (Context) AtomicExpr(TheCall->getCallee()->getLocStart(), 1586 SubExprs, ResultType, Op, 1587 TheCall->getRParenLoc()); 1588 1589 if ((Op == AtomicExpr::AO__c11_atomic_load || 1590 (Op == AtomicExpr::AO__c11_atomic_store)) && 1591 Context.AtomicUsesUnsupportedLibcall(AE)) 1592 Diag(AE->getLocStart(), diag::err_atomic_load_store_uses_lib) << 1593 ((Op == AtomicExpr::AO__c11_atomic_load) ? 0 : 1); 1594 1595 return AE; 1596 } 1597 1598 1599 /// checkBuiltinArgument - Given a call to a builtin function, perform 1600 /// normal type-checking on the given argument, updating the call in 1601 /// place. This is useful when a builtin function requires custom 1602 /// type-checking for some of its arguments but not necessarily all of 1603 /// them. 1604 /// 1605 /// Returns true on error. 1606 static bool checkBuiltinArgument(Sema &S, CallExpr *E, unsigned ArgIndex) { 1607 FunctionDecl *Fn = E->getDirectCallee(); 1608 assert(Fn && "builtin call without direct callee!"); 1609 1610 ParmVarDecl *Param = Fn->getParamDecl(ArgIndex); 1611 InitializedEntity Entity = 1612 InitializedEntity::InitializeParameter(S.Context, Param); 1613 1614 ExprResult Arg = E->getArg(0); 1615 Arg = S.PerformCopyInitialization(Entity, SourceLocation(), Arg); 1616 if (Arg.isInvalid()) 1617 return true; 1618 1619 E->setArg(ArgIndex, Arg.get()); 1620 return false; 1621 } 1622 1623 /// SemaBuiltinAtomicOverloaded - We have a call to a function like 1624 /// __sync_fetch_and_add, which is an overloaded function based on the pointer 1625 /// type of its first argument. The main ActOnCallExpr routines have already 1626 /// promoted the types of arguments because all of these calls are prototyped as 1627 /// void(...). 1628 /// 1629 /// This function goes through and does final semantic checking for these 1630 /// builtins, 1631 ExprResult 1632 Sema::SemaBuiltinAtomicOverloaded(ExprResult TheCallResult) { 1633 CallExpr *TheCall = (CallExpr *)TheCallResult.get(); 1634 DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts()); 1635 FunctionDecl *FDecl = cast<FunctionDecl>(DRE->getDecl()); 1636 1637 // Ensure that we have at least one argument to do type inference from. 1638 if (TheCall->getNumArgs() < 1) { 1639 Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args_at_least) 1640 << 0 << 1 << TheCall->getNumArgs() 1641 << TheCall->getCallee()->getSourceRange(); 1642 return ExprError(); 1643 } 1644 1645 // Inspect the first argument of the atomic builtin. This should always be 1646 // a pointer type, whose element is an integral scalar or pointer type. 1647 // Because it is a pointer type, we don't have to worry about any implicit 1648 // casts here. 1649 // FIXME: We don't allow floating point scalars as input. 1650 Expr *FirstArg = TheCall->getArg(0); 1651 ExprResult FirstArgResult = DefaultFunctionArrayLvalueConversion(FirstArg); 1652 if (FirstArgResult.isInvalid()) 1653 return ExprError(); 1654 FirstArg = FirstArgResult.get(); 1655 TheCall->setArg(0, FirstArg); 1656 1657 const PointerType *pointerType = FirstArg->getType()->getAs<PointerType>(); 1658 if (!pointerType) { 1659 Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer) 1660 << FirstArg->getType() << FirstArg->getSourceRange(); 1661 return ExprError(); 1662 } 1663 1664 QualType ValType = pointerType->getPointeeType(); 1665 if (!ValType->isIntegerType() && !ValType->isAnyPointerType() && 1666 !ValType->isBlockPointerType()) { 1667 Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer_intptr) 1668 << FirstArg->getType() << FirstArg->getSourceRange(); 1669 return ExprError(); 1670 } 1671 1672 switch (ValType.getObjCLifetime()) { 1673 case Qualifiers::OCL_None: 1674 case Qualifiers::OCL_ExplicitNone: 1675 // okay 1676 break; 1677 1678 case Qualifiers::OCL_Weak: 1679 case Qualifiers::OCL_Strong: 1680 case Qualifiers::OCL_Autoreleasing: 1681 Diag(DRE->getLocStart(), diag::err_arc_atomic_ownership) 1682 << ValType << FirstArg->getSourceRange(); 1683 return ExprError(); 1684 } 1685 1686 // Strip any qualifiers off ValType. 1687 ValType = ValType.getUnqualifiedType(); 1688 1689 // The majority of builtins return a value, but a few have special return 1690 // types, so allow them to override appropriately below. 1691 QualType ResultType = ValType; 1692 1693 // We need to figure out which concrete builtin this maps onto. For example, 1694 // __sync_fetch_and_add with a 2 byte object turns into 1695 // __sync_fetch_and_add_2. 1696 #define BUILTIN_ROW(x) \ 1697 { Builtin::BI##x##_1, Builtin::BI##x##_2, Builtin::BI##x##_4, \ 1698 Builtin::BI##x##_8, Builtin::BI##x##_16 } 1699 1700 static const unsigned BuiltinIndices[][5] = { 1701 BUILTIN_ROW(__sync_fetch_and_add), 1702 BUILTIN_ROW(__sync_fetch_and_sub), 1703 BUILTIN_ROW(__sync_fetch_and_or), 1704 BUILTIN_ROW(__sync_fetch_and_and), 1705 BUILTIN_ROW(__sync_fetch_and_xor), 1706 BUILTIN_ROW(__sync_fetch_and_nand), 1707 1708 BUILTIN_ROW(__sync_add_and_fetch), 1709 BUILTIN_ROW(__sync_sub_and_fetch), 1710 BUILTIN_ROW(__sync_and_and_fetch), 1711 BUILTIN_ROW(__sync_or_and_fetch), 1712 BUILTIN_ROW(__sync_xor_and_fetch), 1713 BUILTIN_ROW(__sync_nand_and_fetch), 1714 1715 BUILTIN_ROW(__sync_val_compare_and_swap), 1716 BUILTIN_ROW(__sync_bool_compare_and_swap), 1717 BUILTIN_ROW(__sync_lock_test_and_set), 1718 BUILTIN_ROW(__sync_lock_release), 1719 BUILTIN_ROW(__sync_swap) 1720 }; 1721 #undef BUILTIN_ROW 1722 1723 // Determine the index of the size. 1724 unsigned SizeIndex; 1725 switch (Context.getTypeSizeInChars(ValType).getQuantity()) { 1726 case 1: SizeIndex = 0; break; 1727 case 2: SizeIndex = 1; break; 1728 case 4: SizeIndex = 2; break; 1729 case 8: SizeIndex = 3; break; 1730 case 16: SizeIndex = 4; break; 1731 default: 1732 Diag(DRE->getLocStart(), diag::err_atomic_builtin_pointer_size) 1733 << FirstArg->getType() << FirstArg->getSourceRange(); 1734 return ExprError(); 1735 } 1736 1737 // Each of these builtins has one pointer argument, followed by some number of 1738 // values (0, 1 or 2) followed by a potentially empty varags list of stuff 1739 // that we ignore. Find out which row of BuiltinIndices to read from as well 1740 // as the number of fixed args. 1741 unsigned BuiltinID = FDecl->getBuiltinID(); 1742 unsigned BuiltinIndex, NumFixed = 1; 1743 bool WarnAboutSemanticsChange = false; 1744 switch (BuiltinID) { 1745 default: llvm_unreachable("Unknown overloaded atomic builtin!"); 1746 case Builtin::BI__sync_fetch_and_add: 1747 case Builtin::BI__sync_fetch_and_add_1: 1748 case Builtin::BI__sync_fetch_and_add_2: 1749 case Builtin::BI__sync_fetch_and_add_4: 1750 case Builtin::BI__sync_fetch_and_add_8: 1751 case Builtin::BI__sync_fetch_and_add_16: 1752 BuiltinIndex = 0; 1753 break; 1754 1755 case Builtin::BI__sync_fetch_and_sub: 1756 case Builtin::BI__sync_fetch_and_sub_1: 1757 case Builtin::BI__sync_fetch_and_sub_2: 1758 case Builtin::BI__sync_fetch_and_sub_4: 1759 case Builtin::BI__sync_fetch_and_sub_8: 1760 case Builtin::BI__sync_fetch_and_sub_16: 1761 BuiltinIndex = 1; 1762 break; 1763 1764 case Builtin::BI__sync_fetch_and_or: 1765 case Builtin::BI__sync_fetch_and_or_1: 1766 case Builtin::BI__sync_fetch_and_or_2: 1767 case Builtin::BI__sync_fetch_and_or_4: 1768 case Builtin::BI__sync_fetch_and_or_8: 1769 case Builtin::BI__sync_fetch_and_or_16: 1770 BuiltinIndex = 2; 1771 break; 1772 1773 case Builtin::BI__sync_fetch_and_and: 1774 case Builtin::BI__sync_fetch_and_and_1: 1775 case Builtin::BI__sync_fetch_and_and_2: 1776 case Builtin::BI__sync_fetch_and_and_4: 1777 case Builtin::BI__sync_fetch_and_and_8: 1778 case Builtin::BI__sync_fetch_and_and_16: 1779 BuiltinIndex = 3; 1780 break; 1781 1782 case Builtin::BI__sync_fetch_and_xor: 1783 case Builtin::BI__sync_fetch_and_xor_1: 1784 case Builtin::BI__sync_fetch_and_xor_2: 1785 case Builtin::BI__sync_fetch_and_xor_4: 1786 case Builtin::BI__sync_fetch_and_xor_8: 1787 case Builtin::BI__sync_fetch_and_xor_16: 1788 BuiltinIndex = 4; 1789 break; 1790 1791 case Builtin::BI__sync_fetch_and_nand: 1792 case Builtin::BI__sync_fetch_and_nand_1: 1793 case Builtin::BI__sync_fetch_and_nand_2: 1794 case Builtin::BI__sync_fetch_and_nand_4: 1795 case Builtin::BI__sync_fetch_and_nand_8: 1796 case Builtin::BI__sync_fetch_and_nand_16: 1797 BuiltinIndex = 5; 1798 WarnAboutSemanticsChange = true; 1799 break; 1800 1801 case Builtin::BI__sync_add_and_fetch: 1802 case Builtin::BI__sync_add_and_fetch_1: 1803 case Builtin::BI__sync_add_and_fetch_2: 1804 case Builtin::BI__sync_add_and_fetch_4: 1805 case Builtin::BI__sync_add_and_fetch_8: 1806 case Builtin::BI__sync_add_and_fetch_16: 1807 BuiltinIndex = 6; 1808 break; 1809 1810 case Builtin::BI__sync_sub_and_fetch: 1811 case Builtin::BI__sync_sub_and_fetch_1: 1812 case Builtin::BI__sync_sub_and_fetch_2: 1813 case Builtin::BI__sync_sub_and_fetch_4: 1814 case Builtin::BI__sync_sub_and_fetch_8: 1815 case Builtin::BI__sync_sub_and_fetch_16: 1816 BuiltinIndex = 7; 1817 break; 1818 1819 case Builtin::BI__sync_and_and_fetch: 1820 case Builtin::BI__sync_and_and_fetch_1: 1821 case Builtin::BI__sync_and_and_fetch_2: 1822 case Builtin::BI__sync_and_and_fetch_4: 1823 case Builtin::BI__sync_and_and_fetch_8: 1824 case Builtin::BI__sync_and_and_fetch_16: 1825 BuiltinIndex = 8; 1826 break; 1827 1828 case Builtin::BI__sync_or_and_fetch: 1829 case Builtin::BI__sync_or_and_fetch_1: 1830 case Builtin::BI__sync_or_and_fetch_2: 1831 case Builtin::BI__sync_or_and_fetch_4: 1832 case Builtin::BI__sync_or_and_fetch_8: 1833 case Builtin::BI__sync_or_and_fetch_16: 1834 BuiltinIndex = 9; 1835 break; 1836 1837 case Builtin::BI__sync_xor_and_fetch: 1838 case Builtin::BI__sync_xor_and_fetch_1: 1839 case Builtin::BI__sync_xor_and_fetch_2: 1840 case Builtin::BI__sync_xor_and_fetch_4: 1841 case Builtin::BI__sync_xor_and_fetch_8: 1842 case Builtin::BI__sync_xor_and_fetch_16: 1843 BuiltinIndex = 10; 1844 break; 1845 1846 case Builtin::BI__sync_nand_and_fetch: 1847 case Builtin::BI__sync_nand_and_fetch_1: 1848 case Builtin::BI__sync_nand_and_fetch_2: 1849 case Builtin::BI__sync_nand_and_fetch_4: 1850 case Builtin::BI__sync_nand_and_fetch_8: 1851 case Builtin::BI__sync_nand_and_fetch_16: 1852 BuiltinIndex = 11; 1853 WarnAboutSemanticsChange = true; 1854 break; 1855 1856 case Builtin::BI__sync_val_compare_and_swap: 1857 case Builtin::BI__sync_val_compare_and_swap_1: 1858 case Builtin::BI__sync_val_compare_and_swap_2: 1859 case Builtin::BI__sync_val_compare_and_swap_4: 1860 case Builtin::BI__sync_val_compare_and_swap_8: 1861 case Builtin::BI__sync_val_compare_and_swap_16: 1862 BuiltinIndex = 12; 1863 NumFixed = 2; 1864 break; 1865 1866 case Builtin::BI__sync_bool_compare_and_swap: 1867 case Builtin::BI__sync_bool_compare_and_swap_1: 1868 case Builtin::BI__sync_bool_compare_and_swap_2: 1869 case Builtin::BI__sync_bool_compare_and_swap_4: 1870 case Builtin::BI__sync_bool_compare_and_swap_8: 1871 case Builtin::BI__sync_bool_compare_and_swap_16: 1872 BuiltinIndex = 13; 1873 NumFixed = 2; 1874 ResultType = Context.BoolTy; 1875 break; 1876 1877 case Builtin::BI__sync_lock_test_and_set: 1878 case Builtin::BI__sync_lock_test_and_set_1: 1879 case Builtin::BI__sync_lock_test_and_set_2: 1880 case Builtin::BI__sync_lock_test_and_set_4: 1881 case Builtin::BI__sync_lock_test_and_set_8: 1882 case Builtin::BI__sync_lock_test_and_set_16: 1883 BuiltinIndex = 14; 1884 break; 1885 1886 case Builtin::BI__sync_lock_release: 1887 case Builtin::BI__sync_lock_release_1: 1888 case Builtin::BI__sync_lock_release_2: 1889 case Builtin::BI__sync_lock_release_4: 1890 case Builtin::BI__sync_lock_release_8: 1891 case Builtin::BI__sync_lock_release_16: 1892 BuiltinIndex = 15; 1893 NumFixed = 0; 1894 ResultType = Context.VoidTy; 1895 break; 1896 1897 case Builtin::BI__sync_swap: 1898 case Builtin::BI__sync_swap_1: 1899 case Builtin::BI__sync_swap_2: 1900 case Builtin::BI__sync_swap_4: 1901 case Builtin::BI__sync_swap_8: 1902 case Builtin::BI__sync_swap_16: 1903 BuiltinIndex = 16; 1904 break; 1905 } 1906 1907 // Now that we know how many fixed arguments we expect, first check that we 1908 // have at least that many. 1909 if (TheCall->getNumArgs() < 1+NumFixed) { 1910 Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args_at_least) 1911 << 0 << 1+NumFixed << TheCall->getNumArgs() 1912 << TheCall->getCallee()->getSourceRange(); 1913 return ExprError(); 1914 } 1915 1916 if (WarnAboutSemanticsChange) { 1917 Diag(TheCall->getLocEnd(), diag::warn_sync_fetch_and_nand_semantics_change) 1918 << TheCall->getCallee()->getSourceRange(); 1919 } 1920 1921 // Get the decl for the concrete builtin from this, we can tell what the 1922 // concrete integer type we should convert to is. 1923 unsigned NewBuiltinID = BuiltinIndices[BuiltinIndex][SizeIndex]; 1924 const char *NewBuiltinName = Context.BuiltinInfo.GetName(NewBuiltinID); 1925 FunctionDecl *NewBuiltinDecl; 1926 if (NewBuiltinID == BuiltinID) 1927 NewBuiltinDecl = FDecl; 1928 else { 1929 // Perform builtin lookup to avoid redeclaring it. 1930 DeclarationName DN(&Context.Idents.get(NewBuiltinName)); 1931 LookupResult Res(*this, DN, DRE->getLocStart(), LookupOrdinaryName); 1932 LookupName(Res, TUScope, /*AllowBuiltinCreation=*/true); 1933 assert(Res.getFoundDecl()); 1934 NewBuiltinDecl = dyn_cast<FunctionDecl>(Res.getFoundDecl()); 1935 if (!NewBuiltinDecl) 1936 return ExprError(); 1937 } 1938 1939 // The first argument --- the pointer --- has a fixed type; we 1940 // deduce the types of the rest of the arguments accordingly. Walk 1941 // the remaining arguments, converting them to the deduced value type. 1942 for (unsigned i = 0; i != NumFixed; ++i) { 1943 ExprResult Arg = TheCall->getArg(i+1); 1944 1945 // GCC does an implicit conversion to the pointer or integer ValType. This 1946 // can fail in some cases (1i -> int**), check for this error case now. 1947 // Initialize the argument. 1948 InitializedEntity Entity = InitializedEntity::InitializeParameter(Context, 1949 ValType, /*consume*/ false); 1950 Arg = PerformCopyInitialization(Entity, SourceLocation(), Arg); 1951 if (Arg.isInvalid()) 1952 return ExprError(); 1953 1954 // Okay, we have something that *can* be converted to the right type. Check 1955 // to see if there is a potentially weird extension going on here. This can 1956 // happen when you do an atomic operation on something like an char* and 1957 // pass in 42. The 42 gets converted to char. This is even more strange 1958 // for things like 45.123 -> char, etc. 1959 // FIXME: Do this check. 1960 TheCall->setArg(i+1, Arg.get()); 1961 } 1962 1963 ASTContext& Context = this->getASTContext(); 1964 1965 // Create a new DeclRefExpr to refer to the new decl. 1966 DeclRefExpr* NewDRE = DeclRefExpr::Create( 1967 Context, 1968 DRE->getQualifierLoc(), 1969 SourceLocation(), 1970 NewBuiltinDecl, 1971 /*enclosing*/ false, 1972 DRE->getLocation(), 1973 Context.BuiltinFnTy, 1974 DRE->getValueKind()); 1975 1976 // Set the callee in the CallExpr. 1977 // FIXME: This loses syntactic information. 1978 QualType CalleePtrTy = Context.getPointerType(NewBuiltinDecl->getType()); 1979 ExprResult PromotedCall = ImpCastExprToType(NewDRE, CalleePtrTy, 1980 CK_BuiltinFnToFnPtr); 1981 TheCall->setCallee(PromotedCall.get()); 1982 1983 // Change the result type of the call to match the original value type. This 1984 // is arbitrary, but the codegen for these builtins ins design to handle it 1985 // gracefully. 1986 TheCall->setType(ResultType); 1987 1988 return TheCallResult; 1989 } 1990 1991 /// CheckObjCString - Checks that the argument to the builtin 1992 /// CFString constructor is correct 1993 /// Note: It might also make sense to do the UTF-16 conversion here (would 1994 /// simplify the backend). 1995 bool Sema::CheckObjCString(Expr *Arg) { 1996 Arg = Arg->IgnoreParenCasts(); 1997 StringLiteral *Literal = dyn_cast<StringLiteral>(Arg); 1998 1999 if (!Literal || !Literal->isAscii()) { 2000 Diag(Arg->getLocStart(), diag::err_cfstring_literal_not_string_constant) 2001 << Arg->getSourceRange(); 2002 return true; 2003 } 2004 2005 if (Literal->containsNonAsciiOrNull()) { 2006 StringRef String = Literal->getString(); 2007 unsigned NumBytes = String.size(); 2008 SmallVector<UTF16, 128> ToBuf(NumBytes); 2009 const UTF8 *FromPtr = (const UTF8 *)String.data(); 2010 UTF16 *ToPtr = &ToBuf[0]; 2011 2012 ConversionResult Result = ConvertUTF8toUTF16(&FromPtr, FromPtr + NumBytes, 2013 &ToPtr, ToPtr + NumBytes, 2014 strictConversion); 2015 // Check for conversion failure. 2016 if (Result != conversionOK) 2017 Diag(Arg->getLocStart(), 2018 diag::warn_cfstring_truncated) << Arg->getSourceRange(); 2019 } 2020 return false; 2021 } 2022 2023 /// SemaBuiltinVAStart - Check the arguments to __builtin_va_start for validity. 2024 /// Emit an error and return true on failure, return false on success. 2025 bool Sema::SemaBuiltinVAStart(CallExpr *TheCall) { 2026 Expr *Fn = TheCall->getCallee(); 2027 if (TheCall->getNumArgs() > 2) { 2028 Diag(TheCall->getArg(2)->getLocStart(), 2029 diag::err_typecheck_call_too_many_args) 2030 << 0 /*function call*/ << 2 << TheCall->getNumArgs() 2031 << Fn->getSourceRange() 2032 << SourceRange(TheCall->getArg(2)->getLocStart(), 2033 (*(TheCall->arg_end()-1))->getLocEnd()); 2034 return true; 2035 } 2036 2037 if (TheCall->getNumArgs() < 2) { 2038 return Diag(TheCall->getLocEnd(), 2039 diag::err_typecheck_call_too_few_args_at_least) 2040 << 0 /*function call*/ << 2 << TheCall->getNumArgs(); 2041 } 2042 2043 // Type-check the first argument normally. 2044 if (checkBuiltinArgument(*this, TheCall, 0)) 2045 return true; 2046 2047 // Determine whether the current function is variadic or not. 2048 BlockScopeInfo *CurBlock = getCurBlock(); 2049 bool isVariadic; 2050 if (CurBlock) 2051 isVariadic = CurBlock->TheDecl->isVariadic(); 2052 else if (FunctionDecl *FD = getCurFunctionDecl()) 2053 isVariadic = FD->isVariadic(); 2054 else 2055 isVariadic = getCurMethodDecl()->isVariadic(); 2056 2057 if (!isVariadic) { 2058 Diag(Fn->getLocStart(), diag::err_va_start_used_in_non_variadic_function); 2059 return true; 2060 } 2061 2062 // Verify that the second argument to the builtin is the last argument of the 2063 // current function or method. 2064 bool SecondArgIsLastNamedArgument = false; 2065 const Expr *Arg = TheCall->getArg(1)->IgnoreParenCasts(); 2066 2067 // These are valid if SecondArgIsLastNamedArgument is false after the next 2068 // block. 2069 QualType Type; 2070 SourceLocation ParamLoc; 2071 2072 if (const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(Arg)) { 2073 if (const ParmVarDecl *PV = dyn_cast<ParmVarDecl>(DR->getDecl())) { 2074 // FIXME: This isn't correct for methods (results in bogus warning). 2075 // Get the last formal in the current function. 2076 const ParmVarDecl *LastArg; 2077 if (CurBlock) 2078 LastArg = *(CurBlock->TheDecl->param_end()-1); 2079 else if (FunctionDecl *FD = getCurFunctionDecl()) 2080 LastArg = *(FD->param_end()-1); 2081 else 2082 LastArg = *(getCurMethodDecl()->param_end()-1); 2083 SecondArgIsLastNamedArgument = PV == LastArg; 2084 2085 Type = PV->getType(); 2086 ParamLoc = PV->getLocation(); 2087 } 2088 } 2089 2090 if (!SecondArgIsLastNamedArgument) 2091 Diag(TheCall->getArg(1)->getLocStart(), 2092 diag::warn_second_parameter_of_va_start_not_last_named_argument); 2093 else if (Type->isReferenceType()) { 2094 Diag(Arg->getLocStart(), 2095 diag::warn_va_start_of_reference_type_is_undefined); 2096 Diag(ParamLoc, diag::note_parameter_type) << Type; 2097 } 2098 2099 TheCall->setType(Context.VoidTy); 2100 return false; 2101 } 2102 2103 bool Sema::SemaBuiltinVAStartARM(CallExpr *Call) { 2104 // void __va_start(va_list *ap, const char *named_addr, size_t slot_size, 2105 // const char *named_addr); 2106 2107 Expr *Func = Call->getCallee(); 2108 2109 if (Call->getNumArgs() < 3) 2110 return Diag(Call->getLocEnd(), 2111 diag::err_typecheck_call_too_few_args_at_least) 2112 << 0 /*function call*/ << 3 << Call->getNumArgs(); 2113 2114 // Determine whether the current function is variadic or not. 2115 bool IsVariadic; 2116 if (BlockScopeInfo *CurBlock = getCurBlock()) 2117 IsVariadic = CurBlock->TheDecl->isVariadic(); 2118 else if (FunctionDecl *FD = getCurFunctionDecl()) 2119 IsVariadic = FD->isVariadic(); 2120 else if (ObjCMethodDecl *MD = getCurMethodDecl()) 2121 IsVariadic = MD->isVariadic(); 2122 else 2123 llvm_unreachable("unexpected statement type"); 2124 2125 if (!IsVariadic) { 2126 Diag(Func->getLocStart(), diag::err_va_start_used_in_non_variadic_function); 2127 return true; 2128 } 2129 2130 // Type-check the first argument normally. 2131 if (checkBuiltinArgument(*this, Call, 0)) 2132 return true; 2133 2134 static const struct { 2135 unsigned ArgNo; 2136 QualType Type; 2137 } ArgumentTypes[] = { 2138 { 1, Context.getPointerType(Context.CharTy.withConst()) }, 2139 { 2, Context.getSizeType() }, 2140 }; 2141 2142 for (const auto &AT : ArgumentTypes) { 2143 const Expr *Arg = Call->getArg(AT.ArgNo)->IgnoreParens(); 2144 if (Arg->getType().getCanonicalType() == AT.Type.getCanonicalType()) 2145 continue; 2146 Diag(Arg->getLocStart(), diag::err_typecheck_convert_incompatible) 2147 << Arg->getType() << AT.Type << 1 /* different class */ 2148 << 0 /* qualifier difference */ << 3 /* parameter mismatch */ 2149 << AT.ArgNo + 1 << Arg->getType() << AT.Type; 2150 } 2151 2152 return false; 2153 } 2154 2155 /// SemaBuiltinUnorderedCompare - Handle functions like __builtin_isgreater and 2156 /// friends. This is declared to take (...), so we have to check everything. 2157 bool Sema::SemaBuiltinUnorderedCompare(CallExpr *TheCall) { 2158 if (TheCall->getNumArgs() < 2) 2159 return Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args) 2160 << 0 << 2 << TheCall->getNumArgs()/*function call*/; 2161 if (TheCall->getNumArgs() > 2) 2162 return Diag(TheCall->getArg(2)->getLocStart(), 2163 diag::err_typecheck_call_too_many_args) 2164 << 0 /*function call*/ << 2 << TheCall->getNumArgs() 2165 << SourceRange(TheCall->getArg(2)->getLocStart(), 2166 (*(TheCall->arg_end()-1))->getLocEnd()); 2167 2168 ExprResult OrigArg0 = TheCall->getArg(0); 2169 ExprResult OrigArg1 = TheCall->getArg(1); 2170 2171 // Do standard promotions between the two arguments, returning their common 2172 // type. 2173 QualType Res = UsualArithmeticConversions(OrigArg0, OrigArg1, false); 2174 if (OrigArg0.isInvalid() || OrigArg1.isInvalid()) 2175 return true; 2176 2177 // Make sure any conversions are pushed back into the call; this is 2178 // type safe since unordered compare builtins are declared as "_Bool 2179 // foo(...)". 2180 TheCall->setArg(0, OrigArg0.get()); 2181 TheCall->setArg(1, OrigArg1.get()); 2182 2183 if (OrigArg0.get()->isTypeDependent() || OrigArg1.get()->isTypeDependent()) 2184 return false; 2185 2186 // If the common type isn't a real floating type, then the arguments were 2187 // invalid for this operation. 2188 if (Res.isNull() || !Res->isRealFloatingType()) 2189 return Diag(OrigArg0.get()->getLocStart(), 2190 diag::err_typecheck_call_invalid_ordered_compare) 2191 << OrigArg0.get()->getType() << OrigArg1.get()->getType() 2192 << SourceRange(OrigArg0.get()->getLocStart(), OrigArg1.get()->getLocEnd()); 2193 2194 return false; 2195 } 2196 2197 /// SemaBuiltinSemaBuiltinFPClassification - Handle functions like 2198 /// __builtin_isnan and friends. This is declared to take (...), so we have 2199 /// to check everything. We expect the last argument to be a floating point 2200 /// value. 2201 bool Sema::SemaBuiltinFPClassification(CallExpr *TheCall, unsigned NumArgs) { 2202 if (TheCall->getNumArgs() < NumArgs) 2203 return Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args) 2204 << 0 << NumArgs << TheCall->getNumArgs()/*function call*/; 2205 if (TheCall->getNumArgs() > NumArgs) 2206 return Diag(TheCall->getArg(NumArgs)->getLocStart(), 2207 diag::err_typecheck_call_too_many_args) 2208 << 0 /*function call*/ << NumArgs << TheCall->getNumArgs() 2209 << SourceRange(TheCall->getArg(NumArgs)->getLocStart(), 2210 (*(TheCall->arg_end()-1))->getLocEnd()); 2211 2212 Expr *OrigArg = TheCall->getArg(NumArgs-1); 2213 2214 if (OrigArg->isTypeDependent()) 2215 return false; 2216 2217 // This operation requires a non-_Complex floating-point number. 2218 if (!OrigArg->getType()->isRealFloatingType()) 2219 return Diag(OrigArg->getLocStart(), 2220 diag::err_typecheck_call_invalid_unary_fp) 2221 << OrigArg->getType() << OrigArg->getSourceRange(); 2222 2223 // If this is an implicit conversion from float -> double, remove it. 2224 if (ImplicitCastExpr *Cast = dyn_cast<ImplicitCastExpr>(OrigArg)) { 2225 Expr *CastArg = Cast->getSubExpr(); 2226 if (CastArg->getType()->isSpecificBuiltinType(BuiltinType::Float)) { 2227 assert(Cast->getType()->isSpecificBuiltinType(BuiltinType::Double) && 2228 "promotion from float to double is the only expected cast here"); 2229 Cast->setSubExpr(nullptr); 2230 TheCall->setArg(NumArgs-1, CastArg); 2231 } 2232 } 2233 2234 return false; 2235 } 2236 2237 /// SemaBuiltinShuffleVector - Handle __builtin_shufflevector. 2238 // This is declared to take (...), so we have to check everything. 2239 ExprResult Sema::SemaBuiltinShuffleVector(CallExpr *TheCall) { 2240 if (TheCall->getNumArgs() < 2) 2241 return ExprError(Diag(TheCall->getLocEnd(), 2242 diag::err_typecheck_call_too_few_args_at_least) 2243 << 0 /*function call*/ << 2 << TheCall->getNumArgs() 2244 << TheCall->getSourceRange()); 2245 2246 // Determine which of the following types of shufflevector we're checking: 2247 // 1) unary, vector mask: (lhs, mask) 2248 // 2) binary, vector mask: (lhs, rhs, mask) 2249 // 3) binary, scalar mask: (lhs, rhs, index, ..., index) 2250 QualType resType = TheCall->getArg(0)->getType(); 2251 unsigned numElements = 0; 2252 2253 if (!TheCall->getArg(0)->isTypeDependent() && 2254 !TheCall->getArg(1)->isTypeDependent()) { 2255 QualType LHSType = TheCall->getArg(0)->getType(); 2256 QualType RHSType = TheCall->getArg(1)->getType(); 2257 2258 if (!LHSType->isVectorType() || !RHSType->isVectorType()) 2259 return ExprError(Diag(TheCall->getLocStart(), 2260 diag::err_shufflevector_non_vector) 2261 << SourceRange(TheCall->getArg(0)->getLocStart(), 2262 TheCall->getArg(1)->getLocEnd())); 2263 2264 numElements = LHSType->getAs<VectorType>()->getNumElements(); 2265 unsigned numResElements = TheCall->getNumArgs() - 2; 2266 2267 // Check to see if we have a call with 2 vector arguments, the unary shuffle 2268 // with mask. If so, verify that RHS is an integer vector type with the 2269 // same number of elts as lhs. 2270 if (TheCall->getNumArgs() == 2) { 2271 if (!RHSType->hasIntegerRepresentation() || 2272 RHSType->getAs<VectorType>()->getNumElements() != numElements) 2273 return ExprError(Diag(TheCall->getLocStart(), 2274 diag::err_shufflevector_incompatible_vector) 2275 << SourceRange(TheCall->getArg(1)->getLocStart(), 2276 TheCall->getArg(1)->getLocEnd())); 2277 } else if (!Context.hasSameUnqualifiedType(LHSType, RHSType)) { 2278 return ExprError(Diag(TheCall->getLocStart(), 2279 diag::err_shufflevector_incompatible_vector) 2280 << SourceRange(TheCall->getArg(0)->getLocStart(), 2281 TheCall->getArg(1)->getLocEnd())); 2282 } else if (numElements != numResElements) { 2283 QualType eltType = LHSType->getAs<VectorType>()->getElementType(); 2284 resType = Context.getVectorType(eltType, numResElements, 2285 VectorType::GenericVector); 2286 } 2287 } 2288 2289 for (unsigned i = 2; i < TheCall->getNumArgs(); i++) { 2290 if (TheCall->getArg(i)->isTypeDependent() || 2291 TheCall->getArg(i)->isValueDependent()) 2292 continue; 2293 2294 llvm::APSInt Result(32); 2295 if (!TheCall->getArg(i)->isIntegerConstantExpr(Result, Context)) 2296 return ExprError(Diag(TheCall->getLocStart(), 2297 diag::err_shufflevector_nonconstant_argument) 2298 << TheCall->getArg(i)->getSourceRange()); 2299 2300 // Allow -1 which will be translated to undef in the IR. 2301 if (Result.isSigned() && Result.isAllOnesValue()) 2302 continue; 2303 2304 if (Result.getActiveBits() > 64 || Result.getZExtValue() >= numElements*2) 2305 return ExprError(Diag(TheCall->getLocStart(), 2306 diag::err_shufflevector_argument_too_large) 2307 << TheCall->getArg(i)->getSourceRange()); 2308 } 2309 2310 SmallVector<Expr*, 32> exprs; 2311 2312 for (unsigned i = 0, e = TheCall->getNumArgs(); i != e; i++) { 2313 exprs.push_back(TheCall->getArg(i)); 2314 TheCall->setArg(i, nullptr); 2315 } 2316 2317 return new (Context) ShuffleVectorExpr(Context, exprs, resType, 2318 TheCall->getCallee()->getLocStart(), 2319 TheCall->getRParenLoc()); 2320 } 2321 2322 /// SemaConvertVectorExpr - Handle __builtin_convertvector 2323 ExprResult Sema::SemaConvertVectorExpr(Expr *E, TypeSourceInfo *TInfo, 2324 SourceLocation BuiltinLoc, 2325 SourceLocation RParenLoc) { 2326 ExprValueKind VK = VK_RValue; 2327 ExprObjectKind OK = OK_Ordinary; 2328 QualType DstTy = TInfo->getType(); 2329 QualType SrcTy = E->getType(); 2330 2331 if (!SrcTy->isVectorType() && !SrcTy->isDependentType()) 2332 return ExprError(Diag(BuiltinLoc, 2333 diag::err_convertvector_non_vector) 2334 << E->getSourceRange()); 2335 if (!DstTy->isVectorType() && !DstTy->isDependentType()) 2336 return ExprError(Diag(BuiltinLoc, 2337 diag::err_convertvector_non_vector_type)); 2338 2339 if (!SrcTy->isDependentType() && !DstTy->isDependentType()) { 2340 unsigned SrcElts = SrcTy->getAs<VectorType>()->getNumElements(); 2341 unsigned DstElts = DstTy->getAs<VectorType>()->getNumElements(); 2342 if (SrcElts != DstElts) 2343 return ExprError(Diag(BuiltinLoc, 2344 diag::err_convertvector_incompatible_vector) 2345 << E->getSourceRange()); 2346 } 2347 2348 return new (Context) 2349 ConvertVectorExpr(E, TInfo, DstTy, VK, OK, BuiltinLoc, RParenLoc); 2350 } 2351 2352 /// SemaBuiltinPrefetch - Handle __builtin_prefetch. 2353 // This is declared to take (const void*, ...) and can take two 2354 // optional constant int args. 2355 bool Sema::SemaBuiltinPrefetch(CallExpr *TheCall) { 2356 unsigned NumArgs = TheCall->getNumArgs(); 2357 2358 if (NumArgs > 3) 2359 return Diag(TheCall->getLocEnd(), 2360 diag::err_typecheck_call_too_many_args_at_most) 2361 << 0 /*function call*/ << 3 << NumArgs 2362 << TheCall->getSourceRange(); 2363 2364 // Argument 0 is checked for us and the remaining arguments must be 2365 // constant integers. 2366 for (unsigned i = 1; i != NumArgs; ++i) 2367 if (SemaBuiltinConstantArgRange(TheCall, i, 0, i == 1 ? 1 : 3)) 2368 return true; 2369 2370 return false; 2371 } 2372 2373 /// SemaBuiltinAssume - Handle __assume (MS Extension). 2374 // __assume does not evaluate its arguments, and should warn if its argument 2375 // has side effects. 2376 bool Sema::SemaBuiltinAssume(CallExpr *TheCall) { 2377 Expr *Arg = TheCall->getArg(0); 2378 if (Arg->isInstantiationDependent()) return false; 2379 2380 if (Arg->HasSideEffects(Context)) 2381 return Diag(Arg->getLocStart(), diag::warn_assume_side_effects) 2382 << Arg->getSourceRange() 2383 << cast<FunctionDecl>(TheCall->getCalleeDecl())->getIdentifier(); 2384 2385 return false; 2386 } 2387 2388 /// Handle __builtin_assume_aligned. This is declared 2389 /// as (const void*, size_t, ...) and can take one optional constant int arg. 2390 bool Sema::SemaBuiltinAssumeAligned(CallExpr *TheCall) { 2391 unsigned NumArgs = TheCall->getNumArgs(); 2392 2393 if (NumArgs > 3) 2394 return Diag(TheCall->getLocEnd(), 2395 diag::err_typecheck_call_too_many_args_at_most) 2396 << 0 /*function call*/ << 3 << NumArgs 2397 << TheCall->getSourceRange(); 2398 2399 // The alignment must be a constant integer. 2400 Expr *Arg = TheCall->getArg(1); 2401 2402 // We can't check the value of a dependent argument. 2403 if (!Arg->isTypeDependent() && !Arg->isValueDependent()) { 2404 llvm::APSInt Result; 2405 if (SemaBuiltinConstantArg(TheCall, 1, Result)) 2406 return true; 2407 2408 if (!Result.isPowerOf2()) 2409 return Diag(TheCall->getLocStart(), 2410 diag::err_alignment_not_power_of_two) 2411 << Arg->getSourceRange(); 2412 } 2413 2414 if (NumArgs > 2) { 2415 ExprResult Arg(TheCall->getArg(2)); 2416 InitializedEntity Entity = InitializedEntity::InitializeParameter(Context, 2417 Context.getSizeType(), false); 2418 Arg = PerformCopyInitialization(Entity, SourceLocation(), Arg); 2419 if (Arg.isInvalid()) return true; 2420 TheCall->setArg(2, Arg.get()); 2421 } 2422 2423 return false; 2424 } 2425 2426 /// SemaBuiltinConstantArg - Handle a check if argument ArgNum of CallExpr 2427 /// TheCall is a constant expression. 2428 bool Sema::SemaBuiltinConstantArg(CallExpr *TheCall, int ArgNum, 2429 llvm::APSInt &Result) { 2430 Expr *Arg = TheCall->getArg(ArgNum); 2431 DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts()); 2432 FunctionDecl *FDecl = cast<FunctionDecl>(DRE->getDecl()); 2433 2434 if (Arg->isTypeDependent() || Arg->isValueDependent()) return false; 2435 2436 if (!Arg->isIntegerConstantExpr(Result, Context)) 2437 return Diag(TheCall->getLocStart(), diag::err_constant_integer_arg_type) 2438 << FDecl->getDeclName() << Arg->getSourceRange(); 2439 2440 return false; 2441 } 2442 2443 /// SemaBuiltinConstantArgRange - Handle a check if argument ArgNum of CallExpr 2444 /// TheCall is a constant expression in the range [Low, High]. 2445 bool Sema::SemaBuiltinConstantArgRange(CallExpr *TheCall, int ArgNum, 2446 int Low, int High) { 2447 llvm::APSInt Result; 2448 2449 // We can't check the value of a dependent argument. 2450 Expr *Arg = TheCall->getArg(ArgNum); 2451 if (Arg->isTypeDependent() || Arg->isValueDependent()) 2452 return false; 2453 2454 // Check constant-ness first. 2455 if (SemaBuiltinConstantArg(TheCall, ArgNum, Result)) 2456 return true; 2457 2458 if (Result.getSExtValue() < Low || Result.getSExtValue() > High) 2459 return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range) 2460 << Low << High << Arg->getSourceRange(); 2461 2462 return false; 2463 } 2464 2465 /// SemaBuiltinLongjmp - Handle __builtin_longjmp(void *env[5], int val). 2466 /// This checks that val is a constant 1. 2467 bool Sema::SemaBuiltinLongjmp(CallExpr *TheCall) { 2468 Expr *Arg = TheCall->getArg(1); 2469 llvm::APSInt Result; 2470 2471 // TODO: This is less than ideal. Overload this to take a value. 2472 if (SemaBuiltinConstantArg(TheCall, 1, Result)) 2473 return true; 2474 2475 if (Result != 1) 2476 return Diag(TheCall->getLocStart(), diag::err_builtin_longjmp_invalid_val) 2477 << SourceRange(Arg->getLocStart(), Arg->getLocEnd()); 2478 2479 return false; 2480 } 2481 2482 namespace { 2483 enum StringLiteralCheckType { 2484 SLCT_NotALiteral, 2485 SLCT_UncheckedLiteral, 2486 SLCT_CheckedLiteral 2487 }; 2488 } 2489 2490 // Determine if an expression is a string literal or constant string. 2491 // If this function returns false on the arguments to a function expecting a 2492 // format string, we will usually need to emit a warning. 2493 // True string literals are then checked by CheckFormatString. 2494 static StringLiteralCheckType 2495 checkFormatStringExpr(Sema &S, const Expr *E, ArrayRef<const Expr *> Args, 2496 bool HasVAListArg, unsigned format_idx, 2497 unsigned firstDataArg, Sema::FormatStringType Type, 2498 Sema::VariadicCallType CallType, bool InFunctionCall, 2499 llvm::SmallBitVector &CheckedVarArgs) { 2500 tryAgain: 2501 if (E->isTypeDependent() || E->isValueDependent()) 2502 return SLCT_NotALiteral; 2503 2504 E = E->IgnoreParenCasts(); 2505 2506 if (E->isNullPointerConstant(S.Context, Expr::NPC_ValueDependentIsNotNull)) 2507 // Technically -Wformat-nonliteral does not warn about this case. 2508 // The behavior of printf and friends in this case is implementation 2509 // dependent. Ideally if the format string cannot be null then 2510 // it should have a 'nonnull' attribute in the function prototype. 2511 return SLCT_UncheckedLiteral; 2512 2513 switch (E->getStmtClass()) { 2514 case Stmt::BinaryConditionalOperatorClass: 2515 case Stmt::ConditionalOperatorClass: { 2516 // The expression is a literal if both sub-expressions were, and it was 2517 // completely checked only if both sub-expressions were checked. 2518 const AbstractConditionalOperator *C = 2519 cast<AbstractConditionalOperator>(E); 2520 StringLiteralCheckType Left = 2521 checkFormatStringExpr(S, C->getTrueExpr(), Args, 2522 HasVAListArg, format_idx, firstDataArg, 2523 Type, CallType, InFunctionCall, CheckedVarArgs); 2524 if (Left == SLCT_NotALiteral) 2525 return SLCT_NotALiteral; 2526 StringLiteralCheckType Right = 2527 checkFormatStringExpr(S, C->getFalseExpr(), Args, 2528 HasVAListArg, format_idx, firstDataArg, 2529 Type, CallType, InFunctionCall, CheckedVarArgs); 2530 return Left < Right ? Left : Right; 2531 } 2532 2533 case Stmt::ImplicitCastExprClass: { 2534 E = cast<ImplicitCastExpr>(E)->getSubExpr(); 2535 goto tryAgain; 2536 } 2537 2538 case Stmt::OpaqueValueExprClass: 2539 if (const Expr *src = cast<OpaqueValueExpr>(E)->getSourceExpr()) { 2540 E = src; 2541 goto tryAgain; 2542 } 2543 return SLCT_NotALiteral; 2544 2545 case Stmt::PredefinedExprClass: 2546 // While __func__, etc., are technically not string literals, they 2547 // cannot contain format specifiers and thus are not a security 2548 // liability. 2549 return SLCT_UncheckedLiteral; 2550 2551 case Stmt::DeclRefExprClass: { 2552 const DeclRefExpr *DR = cast<DeclRefExpr>(E); 2553 2554 // As an exception, do not flag errors for variables binding to 2555 // const string literals. 2556 if (const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl())) { 2557 bool isConstant = false; 2558 QualType T = DR->getType(); 2559 2560 if (const ArrayType *AT = S.Context.getAsArrayType(T)) { 2561 isConstant = AT->getElementType().isConstant(S.Context); 2562 } else if (const PointerType *PT = T->getAs<PointerType>()) { 2563 isConstant = T.isConstant(S.Context) && 2564 PT->getPointeeType().isConstant(S.Context); 2565 } else if (T->isObjCObjectPointerType()) { 2566 // In ObjC, there is usually no "const ObjectPointer" type, 2567 // so don't check if the pointee type is constant. 2568 isConstant = T.isConstant(S.Context); 2569 } 2570 2571 if (isConstant) { 2572 if (const Expr *Init = VD->getAnyInitializer()) { 2573 // Look through initializers like const char c[] = { "foo" } 2574 if (const InitListExpr *InitList = dyn_cast<InitListExpr>(Init)) { 2575 if (InitList->isStringLiteralInit()) 2576 Init = InitList->getInit(0)->IgnoreParenImpCasts(); 2577 } 2578 return checkFormatStringExpr(S, Init, Args, 2579 HasVAListArg, format_idx, 2580 firstDataArg, Type, CallType, 2581 /*InFunctionCall*/false, CheckedVarArgs); 2582 } 2583 } 2584 2585 // For vprintf* functions (i.e., HasVAListArg==true), we add a 2586 // special check to see if the format string is a function parameter 2587 // of the function calling the printf function. If the function 2588 // has an attribute indicating it is a printf-like function, then we 2589 // should suppress warnings concerning non-literals being used in a call 2590 // to a vprintf function. For example: 2591 // 2592 // void 2593 // logmessage(char const *fmt __attribute__ (format (printf, 1, 2)), ...){ 2594 // va_list ap; 2595 // va_start(ap, fmt); 2596 // vprintf(fmt, ap); // Do NOT emit a warning about "fmt". 2597 // ... 2598 // } 2599 if (HasVAListArg) { 2600 if (const ParmVarDecl *PV = dyn_cast<ParmVarDecl>(VD)) { 2601 if (const NamedDecl *ND = dyn_cast<NamedDecl>(PV->getDeclContext())) { 2602 int PVIndex = PV->getFunctionScopeIndex() + 1; 2603 for (const auto *PVFormat : ND->specific_attrs<FormatAttr>()) { 2604 // adjust for implicit parameter 2605 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(ND)) 2606 if (MD->isInstance()) 2607 ++PVIndex; 2608 // We also check if the formats are compatible. 2609 // We can't pass a 'scanf' string to a 'printf' function. 2610 if (PVIndex == PVFormat->getFormatIdx() && 2611 Type == S.GetFormatStringType(PVFormat)) 2612 return SLCT_UncheckedLiteral; 2613 } 2614 } 2615 } 2616 } 2617 } 2618 2619 return SLCT_NotALiteral; 2620 } 2621 2622 case Stmt::CallExprClass: 2623 case Stmt::CXXMemberCallExprClass: { 2624 const CallExpr *CE = cast<CallExpr>(E); 2625 if (const NamedDecl *ND = dyn_cast_or_null<NamedDecl>(CE->getCalleeDecl())) { 2626 if (const FormatArgAttr *FA = ND->getAttr<FormatArgAttr>()) { 2627 unsigned ArgIndex = FA->getFormatIdx(); 2628 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(ND)) 2629 if (MD->isInstance()) 2630 --ArgIndex; 2631 const Expr *Arg = CE->getArg(ArgIndex - 1); 2632 2633 return checkFormatStringExpr(S, Arg, Args, 2634 HasVAListArg, format_idx, firstDataArg, 2635 Type, CallType, InFunctionCall, 2636 CheckedVarArgs); 2637 } else if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND)) { 2638 unsigned BuiltinID = FD->getBuiltinID(); 2639 if (BuiltinID == Builtin::BI__builtin___CFStringMakeConstantString || 2640 BuiltinID == Builtin::BI__builtin___NSStringMakeConstantString) { 2641 const Expr *Arg = CE->getArg(0); 2642 return checkFormatStringExpr(S, Arg, Args, 2643 HasVAListArg, format_idx, 2644 firstDataArg, Type, CallType, 2645 InFunctionCall, CheckedVarArgs); 2646 } 2647 } 2648 } 2649 2650 return SLCT_NotALiteral; 2651 } 2652 case Stmt::ObjCStringLiteralClass: 2653 case Stmt::StringLiteralClass: { 2654 const StringLiteral *StrE = nullptr; 2655 2656 if (const ObjCStringLiteral *ObjCFExpr = dyn_cast<ObjCStringLiteral>(E)) 2657 StrE = ObjCFExpr->getString(); 2658 else 2659 StrE = cast<StringLiteral>(E); 2660 2661 if (StrE) { 2662 S.CheckFormatString(StrE, E, Args, HasVAListArg, format_idx, firstDataArg, 2663 Type, InFunctionCall, CallType, CheckedVarArgs); 2664 return SLCT_CheckedLiteral; 2665 } 2666 2667 return SLCT_NotALiteral; 2668 } 2669 2670 default: 2671 return SLCT_NotALiteral; 2672 } 2673 } 2674 2675 Sema::FormatStringType Sema::GetFormatStringType(const FormatAttr *Format) { 2676 return llvm::StringSwitch<FormatStringType>(Format->getType()->getName()) 2677 .Case("scanf", FST_Scanf) 2678 .Cases("printf", "printf0", FST_Printf) 2679 .Cases("NSString", "CFString", FST_NSString) 2680 .Case("strftime", FST_Strftime) 2681 .Case("strfmon", FST_Strfmon) 2682 .Cases("kprintf", "cmn_err", "vcmn_err", "zcmn_err", FST_Kprintf) 2683 .Case("freebsd_kprintf", FST_FreeBSDKPrintf) 2684 .Case("os_trace", FST_OSTrace) 2685 .Default(FST_Unknown); 2686 } 2687 2688 /// CheckFormatArguments - Check calls to printf and scanf (and similar 2689 /// functions) for correct use of format strings. 2690 /// Returns true if a format string has been fully checked. 2691 bool Sema::CheckFormatArguments(const FormatAttr *Format, 2692 ArrayRef<const Expr *> Args, 2693 bool IsCXXMember, 2694 VariadicCallType CallType, 2695 SourceLocation Loc, SourceRange Range, 2696 llvm::SmallBitVector &CheckedVarArgs) { 2697 FormatStringInfo FSI; 2698 if (getFormatStringInfo(Format, IsCXXMember, &FSI)) 2699 return CheckFormatArguments(Args, FSI.HasVAListArg, FSI.FormatIdx, 2700 FSI.FirstDataArg, GetFormatStringType(Format), 2701 CallType, Loc, Range, CheckedVarArgs); 2702 return false; 2703 } 2704 2705 bool Sema::CheckFormatArguments(ArrayRef<const Expr *> Args, 2706 bool HasVAListArg, unsigned format_idx, 2707 unsigned firstDataArg, FormatStringType Type, 2708 VariadicCallType CallType, 2709 SourceLocation Loc, SourceRange Range, 2710 llvm::SmallBitVector &CheckedVarArgs) { 2711 // CHECK: printf/scanf-like function is called with no format string. 2712 if (format_idx >= Args.size()) { 2713 Diag(Loc, diag::warn_missing_format_string) << Range; 2714 return false; 2715 } 2716 2717 const Expr *OrigFormatExpr = Args[format_idx]->IgnoreParenCasts(); 2718 2719 // CHECK: format string is not a string literal. 2720 // 2721 // Dynamically generated format strings are difficult to 2722 // automatically vet at compile time. Requiring that format strings 2723 // are string literals: (1) permits the checking of format strings by 2724 // the compiler and thereby (2) can practically remove the source of 2725 // many format string exploits. 2726 2727 // Format string can be either ObjC string (e.g. @"%d") or 2728 // C string (e.g. "%d") 2729 // ObjC string uses the same format specifiers as C string, so we can use 2730 // the same format string checking logic for both ObjC and C strings. 2731 StringLiteralCheckType CT = 2732 checkFormatStringExpr(*this, OrigFormatExpr, Args, HasVAListArg, 2733 format_idx, firstDataArg, Type, CallType, 2734 /*IsFunctionCall*/true, CheckedVarArgs); 2735 if (CT != SLCT_NotALiteral) 2736 // Literal format string found, check done! 2737 return CT == SLCT_CheckedLiteral; 2738 2739 // Strftime is particular as it always uses a single 'time' argument, 2740 // so it is safe to pass a non-literal string. 2741 if (Type == FST_Strftime) 2742 return false; 2743 2744 // Do not emit diag when the string param is a macro expansion and the 2745 // format is either NSString or CFString. This is a hack to prevent 2746 // diag when using the NSLocalizedString and CFCopyLocalizedString macros 2747 // which are usually used in place of NS and CF string literals. 2748 if (Type == FST_NSString && 2749 SourceMgr.isInSystemMacro(Args[format_idx]->getLocStart())) 2750 return false; 2751 2752 // If there are no arguments specified, warn with -Wformat-security, otherwise 2753 // warn only with -Wformat-nonliteral. 2754 if (Args.size() == firstDataArg) 2755 Diag(Args[format_idx]->getLocStart(), 2756 diag::warn_format_nonliteral_noargs) 2757 << OrigFormatExpr->getSourceRange(); 2758 else 2759 Diag(Args[format_idx]->getLocStart(), 2760 diag::warn_format_nonliteral) 2761 << OrigFormatExpr->getSourceRange(); 2762 return false; 2763 } 2764 2765 namespace { 2766 class CheckFormatHandler : public analyze_format_string::FormatStringHandler { 2767 protected: 2768 Sema &S; 2769 const StringLiteral *FExpr; 2770 const Expr *OrigFormatExpr; 2771 const unsigned FirstDataArg; 2772 const unsigned NumDataArgs; 2773 const char *Beg; // Start of format string. 2774 const bool HasVAListArg; 2775 ArrayRef<const Expr *> Args; 2776 unsigned FormatIdx; 2777 llvm::SmallBitVector CoveredArgs; 2778 bool usesPositionalArgs; 2779 bool atFirstArg; 2780 bool inFunctionCall; 2781 Sema::VariadicCallType CallType; 2782 llvm::SmallBitVector &CheckedVarArgs; 2783 public: 2784 CheckFormatHandler(Sema &s, const StringLiteral *fexpr, 2785 const Expr *origFormatExpr, unsigned firstDataArg, 2786 unsigned numDataArgs, const char *beg, bool hasVAListArg, 2787 ArrayRef<const Expr *> Args, 2788 unsigned formatIdx, bool inFunctionCall, 2789 Sema::VariadicCallType callType, 2790 llvm::SmallBitVector &CheckedVarArgs) 2791 : S(s), FExpr(fexpr), OrigFormatExpr(origFormatExpr), 2792 FirstDataArg(firstDataArg), NumDataArgs(numDataArgs), 2793 Beg(beg), HasVAListArg(hasVAListArg), 2794 Args(Args), FormatIdx(formatIdx), 2795 usesPositionalArgs(false), atFirstArg(true), 2796 inFunctionCall(inFunctionCall), CallType(callType), 2797 CheckedVarArgs(CheckedVarArgs) { 2798 CoveredArgs.resize(numDataArgs); 2799 CoveredArgs.reset(); 2800 } 2801 2802 void DoneProcessing(); 2803 2804 void HandleIncompleteSpecifier(const char *startSpecifier, 2805 unsigned specifierLen) override; 2806 2807 void HandleInvalidLengthModifier( 2808 const analyze_format_string::FormatSpecifier &FS, 2809 const analyze_format_string::ConversionSpecifier &CS, 2810 const char *startSpecifier, unsigned specifierLen, 2811 unsigned DiagID); 2812 2813 void HandleNonStandardLengthModifier( 2814 const analyze_format_string::FormatSpecifier &FS, 2815 const char *startSpecifier, unsigned specifierLen); 2816 2817 void HandleNonStandardConversionSpecifier( 2818 const analyze_format_string::ConversionSpecifier &CS, 2819 const char *startSpecifier, unsigned specifierLen); 2820 2821 void HandlePosition(const char *startPos, unsigned posLen) override; 2822 2823 void HandleInvalidPosition(const char *startSpecifier, 2824 unsigned specifierLen, 2825 analyze_format_string::PositionContext p) override; 2826 2827 void HandleZeroPosition(const char *startPos, unsigned posLen) override; 2828 2829 void HandleNullChar(const char *nullCharacter) override; 2830 2831 template <typename Range> 2832 static void EmitFormatDiagnostic(Sema &S, bool inFunctionCall, 2833 const Expr *ArgumentExpr, 2834 PartialDiagnostic PDiag, 2835 SourceLocation StringLoc, 2836 bool IsStringLocation, Range StringRange, 2837 ArrayRef<FixItHint> Fixit = None); 2838 2839 protected: 2840 bool HandleInvalidConversionSpecifier(unsigned argIndex, SourceLocation Loc, 2841 const char *startSpec, 2842 unsigned specifierLen, 2843 const char *csStart, unsigned csLen); 2844 2845 void HandlePositionalNonpositionalArgs(SourceLocation Loc, 2846 const char *startSpec, 2847 unsigned specifierLen); 2848 2849 SourceRange getFormatStringRange(); 2850 CharSourceRange getSpecifierRange(const char *startSpecifier, 2851 unsigned specifierLen); 2852 SourceLocation getLocationOfByte(const char *x); 2853 2854 const Expr *getDataArg(unsigned i) const; 2855 2856 bool CheckNumArgs(const analyze_format_string::FormatSpecifier &FS, 2857 const analyze_format_string::ConversionSpecifier &CS, 2858 const char *startSpecifier, unsigned specifierLen, 2859 unsigned argIndex); 2860 2861 template <typename Range> 2862 void EmitFormatDiagnostic(PartialDiagnostic PDiag, SourceLocation StringLoc, 2863 bool IsStringLocation, Range StringRange, 2864 ArrayRef<FixItHint> Fixit = None); 2865 }; 2866 } 2867 2868 SourceRange CheckFormatHandler::getFormatStringRange() { 2869 return OrigFormatExpr->getSourceRange(); 2870 } 2871 2872 CharSourceRange CheckFormatHandler:: 2873 getSpecifierRange(const char *startSpecifier, unsigned specifierLen) { 2874 SourceLocation Start = getLocationOfByte(startSpecifier); 2875 SourceLocation End = getLocationOfByte(startSpecifier + specifierLen - 1); 2876 2877 // Advance the end SourceLocation by one due to half-open ranges. 2878 End = End.getLocWithOffset(1); 2879 2880 return CharSourceRange::getCharRange(Start, End); 2881 } 2882 2883 SourceLocation CheckFormatHandler::getLocationOfByte(const char *x) { 2884 return S.getLocationOfStringLiteralByte(FExpr, x - Beg); 2885 } 2886 2887 void CheckFormatHandler::HandleIncompleteSpecifier(const char *startSpecifier, 2888 unsigned specifierLen){ 2889 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_incomplete_specifier), 2890 getLocationOfByte(startSpecifier), 2891 /*IsStringLocation*/true, 2892 getSpecifierRange(startSpecifier, specifierLen)); 2893 } 2894 2895 void CheckFormatHandler::HandleInvalidLengthModifier( 2896 const analyze_format_string::FormatSpecifier &FS, 2897 const analyze_format_string::ConversionSpecifier &CS, 2898 const char *startSpecifier, unsigned specifierLen, unsigned DiagID) { 2899 using namespace analyze_format_string; 2900 2901 const LengthModifier &LM = FS.getLengthModifier(); 2902 CharSourceRange LMRange = getSpecifierRange(LM.getStart(), LM.getLength()); 2903 2904 // See if we know how to fix this length modifier. 2905 Optional<LengthModifier> FixedLM = FS.getCorrectedLengthModifier(); 2906 if (FixedLM) { 2907 EmitFormatDiagnostic(S.PDiag(DiagID) << LM.toString() << CS.toString(), 2908 getLocationOfByte(LM.getStart()), 2909 /*IsStringLocation*/true, 2910 getSpecifierRange(startSpecifier, specifierLen)); 2911 2912 S.Diag(getLocationOfByte(LM.getStart()), diag::note_format_fix_specifier) 2913 << FixedLM->toString() 2914 << FixItHint::CreateReplacement(LMRange, FixedLM->toString()); 2915 2916 } else { 2917 FixItHint Hint; 2918 if (DiagID == diag::warn_format_nonsensical_length) 2919 Hint = FixItHint::CreateRemoval(LMRange); 2920 2921 EmitFormatDiagnostic(S.PDiag(DiagID) << LM.toString() << CS.toString(), 2922 getLocationOfByte(LM.getStart()), 2923 /*IsStringLocation*/true, 2924 getSpecifierRange(startSpecifier, specifierLen), 2925 Hint); 2926 } 2927 } 2928 2929 void CheckFormatHandler::HandleNonStandardLengthModifier( 2930 const analyze_format_string::FormatSpecifier &FS, 2931 const char *startSpecifier, unsigned specifierLen) { 2932 using namespace analyze_format_string; 2933 2934 const LengthModifier &LM = FS.getLengthModifier(); 2935 CharSourceRange LMRange = getSpecifierRange(LM.getStart(), LM.getLength()); 2936 2937 // See if we know how to fix this length modifier. 2938 Optional<LengthModifier> FixedLM = FS.getCorrectedLengthModifier(); 2939 if (FixedLM) { 2940 EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard) 2941 << LM.toString() << 0, 2942 getLocationOfByte(LM.getStart()), 2943 /*IsStringLocation*/true, 2944 getSpecifierRange(startSpecifier, specifierLen)); 2945 2946 S.Diag(getLocationOfByte(LM.getStart()), diag::note_format_fix_specifier) 2947 << FixedLM->toString() 2948 << FixItHint::CreateReplacement(LMRange, FixedLM->toString()); 2949 2950 } else { 2951 EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard) 2952 << LM.toString() << 0, 2953 getLocationOfByte(LM.getStart()), 2954 /*IsStringLocation*/true, 2955 getSpecifierRange(startSpecifier, specifierLen)); 2956 } 2957 } 2958 2959 void CheckFormatHandler::HandleNonStandardConversionSpecifier( 2960 const analyze_format_string::ConversionSpecifier &CS, 2961 const char *startSpecifier, unsigned specifierLen) { 2962 using namespace analyze_format_string; 2963 2964 // See if we know how to fix this conversion specifier. 2965 Optional<ConversionSpecifier> FixedCS = CS.getStandardSpecifier(); 2966 if (FixedCS) { 2967 EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard) 2968 << CS.toString() << /*conversion specifier*/1, 2969 getLocationOfByte(CS.getStart()), 2970 /*IsStringLocation*/true, 2971 getSpecifierRange(startSpecifier, specifierLen)); 2972 2973 CharSourceRange CSRange = getSpecifierRange(CS.getStart(), CS.getLength()); 2974 S.Diag(getLocationOfByte(CS.getStart()), diag::note_format_fix_specifier) 2975 << FixedCS->toString() 2976 << FixItHint::CreateReplacement(CSRange, FixedCS->toString()); 2977 } else { 2978 EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard) 2979 << CS.toString() << /*conversion specifier*/1, 2980 getLocationOfByte(CS.getStart()), 2981 /*IsStringLocation*/true, 2982 getSpecifierRange(startSpecifier, specifierLen)); 2983 } 2984 } 2985 2986 void CheckFormatHandler::HandlePosition(const char *startPos, 2987 unsigned posLen) { 2988 EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard_positional_arg), 2989 getLocationOfByte(startPos), 2990 /*IsStringLocation*/true, 2991 getSpecifierRange(startPos, posLen)); 2992 } 2993 2994 void 2995 CheckFormatHandler::HandleInvalidPosition(const char *startPos, unsigned posLen, 2996 analyze_format_string::PositionContext p) { 2997 EmitFormatDiagnostic(S.PDiag(diag::warn_format_invalid_positional_specifier) 2998 << (unsigned) p, 2999 getLocationOfByte(startPos), /*IsStringLocation*/true, 3000 getSpecifierRange(startPos, posLen)); 3001 } 3002 3003 void CheckFormatHandler::HandleZeroPosition(const char *startPos, 3004 unsigned posLen) { 3005 EmitFormatDiagnostic(S.PDiag(diag::warn_format_zero_positional_specifier), 3006 getLocationOfByte(startPos), 3007 /*IsStringLocation*/true, 3008 getSpecifierRange(startPos, posLen)); 3009 } 3010 3011 void CheckFormatHandler::HandleNullChar(const char *nullCharacter) { 3012 if (!isa<ObjCStringLiteral>(OrigFormatExpr)) { 3013 // The presence of a null character is likely an error. 3014 EmitFormatDiagnostic( 3015 S.PDiag(diag::warn_printf_format_string_contains_null_char), 3016 getLocationOfByte(nullCharacter), /*IsStringLocation*/true, 3017 getFormatStringRange()); 3018 } 3019 } 3020 3021 // Note that this may return NULL if there was an error parsing or building 3022 // one of the argument expressions. 3023 const Expr *CheckFormatHandler::getDataArg(unsigned i) const { 3024 return Args[FirstDataArg + i]; 3025 } 3026 3027 void CheckFormatHandler::DoneProcessing() { 3028 // Does the number of data arguments exceed the number of 3029 // format conversions in the format string? 3030 if (!HasVAListArg) { 3031 // Find any arguments that weren't covered. 3032 CoveredArgs.flip(); 3033 signed notCoveredArg = CoveredArgs.find_first(); 3034 if (notCoveredArg >= 0) { 3035 assert((unsigned)notCoveredArg < NumDataArgs); 3036 if (const Expr *E = getDataArg((unsigned) notCoveredArg)) { 3037 SourceLocation Loc = E->getLocStart(); 3038 if (!S.getSourceManager().isInSystemMacro(Loc)) { 3039 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_data_arg_not_used), 3040 Loc, /*IsStringLocation*/false, 3041 getFormatStringRange()); 3042 } 3043 } 3044 } 3045 } 3046 } 3047 3048 bool 3049 CheckFormatHandler::HandleInvalidConversionSpecifier(unsigned argIndex, 3050 SourceLocation Loc, 3051 const char *startSpec, 3052 unsigned specifierLen, 3053 const char *csStart, 3054 unsigned csLen) { 3055 3056 bool keepGoing = true; 3057 if (argIndex < NumDataArgs) { 3058 // Consider the argument coverered, even though the specifier doesn't 3059 // make sense. 3060 CoveredArgs.set(argIndex); 3061 } 3062 else { 3063 // If argIndex exceeds the number of data arguments we 3064 // don't issue a warning because that is just a cascade of warnings (and 3065 // they may have intended '%%' anyway). We don't want to continue processing 3066 // the format string after this point, however, as we will like just get 3067 // gibberish when trying to match arguments. 3068 keepGoing = false; 3069 } 3070 3071 EmitFormatDiagnostic(S.PDiag(diag::warn_format_invalid_conversion) 3072 << StringRef(csStart, csLen), 3073 Loc, /*IsStringLocation*/true, 3074 getSpecifierRange(startSpec, specifierLen)); 3075 3076 return keepGoing; 3077 } 3078 3079 void 3080 CheckFormatHandler::HandlePositionalNonpositionalArgs(SourceLocation Loc, 3081 const char *startSpec, 3082 unsigned specifierLen) { 3083 EmitFormatDiagnostic( 3084 S.PDiag(diag::warn_format_mix_positional_nonpositional_args), 3085 Loc, /*isStringLoc*/true, getSpecifierRange(startSpec, specifierLen)); 3086 } 3087 3088 bool 3089 CheckFormatHandler::CheckNumArgs( 3090 const analyze_format_string::FormatSpecifier &FS, 3091 const analyze_format_string::ConversionSpecifier &CS, 3092 const char *startSpecifier, unsigned specifierLen, unsigned argIndex) { 3093 3094 if (argIndex >= NumDataArgs) { 3095 PartialDiagnostic PDiag = FS.usesPositionalArg() 3096 ? (S.PDiag(diag::warn_printf_positional_arg_exceeds_data_args) 3097 << (argIndex+1) << NumDataArgs) 3098 : S.PDiag(diag::warn_printf_insufficient_data_args); 3099 EmitFormatDiagnostic( 3100 PDiag, getLocationOfByte(CS.getStart()), /*IsStringLocation*/true, 3101 getSpecifierRange(startSpecifier, specifierLen)); 3102 return false; 3103 } 3104 return true; 3105 } 3106 3107 template<typename Range> 3108 void CheckFormatHandler::EmitFormatDiagnostic(PartialDiagnostic PDiag, 3109 SourceLocation Loc, 3110 bool IsStringLocation, 3111 Range StringRange, 3112 ArrayRef<FixItHint> FixIt) { 3113 EmitFormatDiagnostic(S, inFunctionCall, Args[FormatIdx], PDiag, 3114 Loc, IsStringLocation, StringRange, FixIt); 3115 } 3116 3117 /// \brief If the format string is not within the funcion call, emit a note 3118 /// so that the function call and string are in diagnostic messages. 3119 /// 3120 /// \param InFunctionCall if true, the format string is within the function 3121 /// call and only one diagnostic message will be produced. Otherwise, an 3122 /// extra note will be emitted pointing to location of the format string. 3123 /// 3124 /// \param ArgumentExpr the expression that is passed as the format string 3125 /// argument in the function call. Used for getting locations when two 3126 /// diagnostics are emitted. 3127 /// 3128 /// \param PDiag the callee should already have provided any strings for the 3129 /// diagnostic message. This function only adds locations and fixits 3130 /// to diagnostics. 3131 /// 3132 /// \param Loc primary location for diagnostic. If two diagnostics are 3133 /// required, one will be at Loc and a new SourceLocation will be created for 3134 /// the other one. 3135 /// 3136 /// \param IsStringLocation if true, Loc points to the format string should be 3137 /// used for the note. Otherwise, Loc points to the argument list and will 3138 /// be used with PDiag. 3139 /// 3140 /// \param StringRange some or all of the string to highlight. This is 3141 /// templated so it can accept either a CharSourceRange or a SourceRange. 3142 /// 3143 /// \param FixIt optional fix it hint for the format string. 3144 template<typename Range> 3145 void CheckFormatHandler::EmitFormatDiagnostic(Sema &S, bool InFunctionCall, 3146 const Expr *ArgumentExpr, 3147 PartialDiagnostic PDiag, 3148 SourceLocation Loc, 3149 bool IsStringLocation, 3150 Range StringRange, 3151 ArrayRef<FixItHint> FixIt) { 3152 if (InFunctionCall) { 3153 const Sema::SemaDiagnosticBuilder &D = S.Diag(Loc, PDiag); 3154 D << StringRange; 3155 for (ArrayRef<FixItHint>::iterator I = FixIt.begin(), E = FixIt.end(); 3156 I != E; ++I) { 3157 D << *I; 3158 } 3159 } else { 3160 S.Diag(IsStringLocation ? ArgumentExpr->getExprLoc() : Loc, PDiag) 3161 << ArgumentExpr->getSourceRange(); 3162 3163 const Sema::SemaDiagnosticBuilder &Note = 3164 S.Diag(IsStringLocation ? Loc : StringRange.getBegin(), 3165 diag::note_format_string_defined); 3166 3167 Note << StringRange; 3168 for (ArrayRef<FixItHint>::iterator I = FixIt.begin(), E = FixIt.end(); 3169 I != E; ++I) { 3170 Note << *I; 3171 } 3172 } 3173 } 3174 3175 //===--- CHECK: Printf format string checking ------------------------------===// 3176 3177 namespace { 3178 class CheckPrintfHandler : public CheckFormatHandler { 3179 bool ObjCContext; 3180 public: 3181 CheckPrintfHandler(Sema &s, const StringLiteral *fexpr, 3182 const Expr *origFormatExpr, unsigned firstDataArg, 3183 unsigned numDataArgs, bool isObjC, 3184 const char *beg, bool hasVAListArg, 3185 ArrayRef<const Expr *> Args, 3186 unsigned formatIdx, bool inFunctionCall, 3187 Sema::VariadicCallType CallType, 3188 llvm::SmallBitVector &CheckedVarArgs) 3189 : CheckFormatHandler(s, fexpr, origFormatExpr, firstDataArg, 3190 numDataArgs, beg, hasVAListArg, Args, 3191 formatIdx, inFunctionCall, CallType, CheckedVarArgs), 3192 ObjCContext(isObjC) 3193 {} 3194 3195 3196 bool HandleInvalidPrintfConversionSpecifier( 3197 const analyze_printf::PrintfSpecifier &FS, 3198 const char *startSpecifier, 3199 unsigned specifierLen) override; 3200 3201 bool HandlePrintfSpecifier(const analyze_printf::PrintfSpecifier &FS, 3202 const char *startSpecifier, 3203 unsigned specifierLen) override; 3204 bool checkFormatExpr(const analyze_printf::PrintfSpecifier &FS, 3205 const char *StartSpecifier, 3206 unsigned SpecifierLen, 3207 const Expr *E); 3208 3209 bool HandleAmount(const analyze_format_string::OptionalAmount &Amt, unsigned k, 3210 const char *startSpecifier, unsigned specifierLen); 3211 void HandleInvalidAmount(const analyze_printf::PrintfSpecifier &FS, 3212 const analyze_printf::OptionalAmount &Amt, 3213 unsigned type, 3214 const char *startSpecifier, unsigned specifierLen); 3215 void HandleFlag(const analyze_printf::PrintfSpecifier &FS, 3216 const analyze_printf::OptionalFlag &flag, 3217 const char *startSpecifier, unsigned specifierLen); 3218 void HandleIgnoredFlag(const analyze_printf::PrintfSpecifier &FS, 3219 const analyze_printf::OptionalFlag &ignoredFlag, 3220 const analyze_printf::OptionalFlag &flag, 3221 const char *startSpecifier, unsigned specifierLen); 3222 bool checkForCStrMembers(const analyze_printf::ArgType &AT, 3223 const Expr *E); 3224 3225 }; 3226 } 3227 3228 bool CheckPrintfHandler::HandleInvalidPrintfConversionSpecifier( 3229 const analyze_printf::PrintfSpecifier &FS, 3230 const char *startSpecifier, 3231 unsigned specifierLen) { 3232 const analyze_printf::PrintfConversionSpecifier &CS = 3233 FS.getConversionSpecifier(); 3234 3235 return HandleInvalidConversionSpecifier(FS.getArgIndex(), 3236 getLocationOfByte(CS.getStart()), 3237 startSpecifier, specifierLen, 3238 CS.getStart(), CS.getLength()); 3239 } 3240 3241 bool CheckPrintfHandler::HandleAmount( 3242 const analyze_format_string::OptionalAmount &Amt, 3243 unsigned k, const char *startSpecifier, 3244 unsigned specifierLen) { 3245 3246 if (Amt.hasDataArgument()) { 3247 if (!HasVAListArg) { 3248 unsigned argIndex = Amt.getArgIndex(); 3249 if (argIndex >= NumDataArgs) { 3250 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_asterisk_missing_arg) 3251 << k, 3252 getLocationOfByte(Amt.getStart()), 3253 /*IsStringLocation*/true, 3254 getSpecifierRange(startSpecifier, specifierLen)); 3255 // Don't do any more checking. We will just emit 3256 // spurious errors. 3257 return false; 3258 } 3259 3260 // Type check the data argument. It should be an 'int'. 3261 // Although not in conformance with C99, we also allow the argument to be 3262 // an 'unsigned int' as that is a reasonably safe case. GCC also 3263 // doesn't emit a warning for that case. 3264 CoveredArgs.set(argIndex); 3265 const Expr *Arg = getDataArg(argIndex); 3266 if (!Arg) 3267 return false; 3268 3269 QualType T = Arg->getType(); 3270 3271 const analyze_printf::ArgType &AT = Amt.getArgType(S.Context); 3272 assert(AT.isValid()); 3273 3274 if (!AT.matchesType(S.Context, T)) { 3275 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_asterisk_wrong_type) 3276 << k << AT.getRepresentativeTypeName(S.Context) 3277 << T << Arg->getSourceRange(), 3278 getLocationOfByte(Amt.getStart()), 3279 /*IsStringLocation*/true, 3280 getSpecifierRange(startSpecifier, specifierLen)); 3281 // Don't do any more checking. We will just emit 3282 // spurious errors. 3283 return false; 3284 } 3285 } 3286 } 3287 return true; 3288 } 3289 3290 void CheckPrintfHandler::HandleInvalidAmount( 3291 const analyze_printf::PrintfSpecifier &FS, 3292 const analyze_printf::OptionalAmount &Amt, 3293 unsigned type, 3294 const char *startSpecifier, 3295 unsigned specifierLen) { 3296 const analyze_printf::PrintfConversionSpecifier &CS = 3297 FS.getConversionSpecifier(); 3298 3299 FixItHint fixit = 3300 Amt.getHowSpecified() == analyze_printf::OptionalAmount::Constant 3301 ? FixItHint::CreateRemoval(getSpecifierRange(Amt.getStart(), 3302 Amt.getConstantLength())) 3303 : FixItHint(); 3304 3305 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_nonsensical_optional_amount) 3306 << type << CS.toString(), 3307 getLocationOfByte(Amt.getStart()), 3308 /*IsStringLocation*/true, 3309 getSpecifierRange(startSpecifier, specifierLen), 3310 fixit); 3311 } 3312 3313 void CheckPrintfHandler::HandleFlag(const analyze_printf::PrintfSpecifier &FS, 3314 const analyze_printf::OptionalFlag &flag, 3315 const char *startSpecifier, 3316 unsigned specifierLen) { 3317 // Warn about pointless flag with a fixit removal. 3318 const analyze_printf::PrintfConversionSpecifier &CS = 3319 FS.getConversionSpecifier(); 3320 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_nonsensical_flag) 3321 << flag.toString() << CS.toString(), 3322 getLocationOfByte(flag.getPosition()), 3323 /*IsStringLocation*/true, 3324 getSpecifierRange(startSpecifier, specifierLen), 3325 FixItHint::CreateRemoval( 3326 getSpecifierRange(flag.getPosition(), 1))); 3327 } 3328 3329 void CheckPrintfHandler::HandleIgnoredFlag( 3330 const analyze_printf::PrintfSpecifier &FS, 3331 const analyze_printf::OptionalFlag &ignoredFlag, 3332 const analyze_printf::OptionalFlag &flag, 3333 const char *startSpecifier, 3334 unsigned specifierLen) { 3335 // Warn about ignored flag with a fixit removal. 3336 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_ignored_flag) 3337 << ignoredFlag.toString() << flag.toString(), 3338 getLocationOfByte(ignoredFlag.getPosition()), 3339 /*IsStringLocation*/true, 3340 getSpecifierRange(startSpecifier, specifierLen), 3341 FixItHint::CreateRemoval( 3342 getSpecifierRange(ignoredFlag.getPosition(), 1))); 3343 } 3344 3345 // Determines if the specified is a C++ class or struct containing 3346 // a member with the specified name and kind (e.g. a CXXMethodDecl named 3347 // "c_str()"). 3348 template<typename MemberKind> 3349 static llvm::SmallPtrSet<MemberKind*, 1> 3350 CXXRecordMembersNamed(StringRef Name, Sema &S, QualType Ty) { 3351 const RecordType *RT = Ty->getAs<RecordType>(); 3352 llvm::SmallPtrSet<MemberKind*, 1> Results; 3353 3354 if (!RT) 3355 return Results; 3356 const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(RT->getDecl()); 3357 if (!RD || !RD->getDefinition()) 3358 return Results; 3359 3360 LookupResult R(S, &S.Context.Idents.get(Name), SourceLocation(), 3361 Sema::LookupMemberName); 3362 R.suppressDiagnostics(); 3363 3364 // We just need to include all members of the right kind turned up by the 3365 // filter, at this point. 3366 if (S.LookupQualifiedName(R, RT->getDecl())) 3367 for (LookupResult::iterator I = R.begin(), E = R.end(); I != E; ++I) { 3368 NamedDecl *decl = (*I)->getUnderlyingDecl(); 3369 if (MemberKind *FK = dyn_cast<MemberKind>(decl)) 3370 Results.insert(FK); 3371 } 3372 return Results; 3373 } 3374 3375 /// Check if we could call '.c_str()' on an object. 3376 /// 3377 /// FIXME: This returns the wrong results in some cases (if cv-qualifiers don't 3378 /// allow the call, or if it would be ambiguous). 3379 bool Sema::hasCStrMethod(const Expr *E) { 3380 typedef llvm::SmallPtrSet<CXXMethodDecl*, 1> MethodSet; 3381 MethodSet Results = 3382 CXXRecordMembersNamed<CXXMethodDecl>("c_str", *this, E->getType()); 3383 for (MethodSet::iterator MI = Results.begin(), ME = Results.end(); 3384 MI != ME; ++MI) 3385 if ((*MI)->getMinRequiredArguments() == 0) 3386 return true; 3387 return false; 3388 } 3389 3390 // Check if a (w)string was passed when a (w)char* was needed, and offer a 3391 // better diagnostic if so. AT is assumed to be valid. 3392 // Returns true when a c_str() conversion method is found. 3393 bool CheckPrintfHandler::checkForCStrMembers( 3394 const analyze_printf::ArgType &AT, const Expr *E) { 3395 typedef llvm::SmallPtrSet<CXXMethodDecl*, 1> MethodSet; 3396 3397 MethodSet Results = 3398 CXXRecordMembersNamed<CXXMethodDecl>("c_str", S, E->getType()); 3399 3400 for (MethodSet::iterator MI = Results.begin(), ME = Results.end(); 3401 MI != ME; ++MI) { 3402 const CXXMethodDecl *Method = *MI; 3403 if (Method->getMinRequiredArguments() == 0 && 3404 AT.matchesType(S.Context, Method->getReturnType())) { 3405 // FIXME: Suggest parens if the expression needs them. 3406 SourceLocation EndLoc = S.getLocForEndOfToken(E->getLocEnd()); 3407 S.Diag(E->getLocStart(), diag::note_printf_c_str) 3408 << "c_str()" 3409 << FixItHint::CreateInsertion(EndLoc, ".c_str()"); 3410 return true; 3411 } 3412 } 3413 3414 return false; 3415 } 3416 3417 bool 3418 CheckPrintfHandler::HandlePrintfSpecifier(const analyze_printf::PrintfSpecifier 3419 &FS, 3420 const char *startSpecifier, 3421 unsigned specifierLen) { 3422 3423 using namespace analyze_format_string; 3424 using namespace analyze_printf; 3425 const PrintfConversionSpecifier &CS = FS.getConversionSpecifier(); 3426 3427 if (FS.consumesDataArgument()) { 3428 if (atFirstArg) { 3429 atFirstArg = false; 3430 usesPositionalArgs = FS.usesPositionalArg(); 3431 } 3432 else if (usesPositionalArgs != FS.usesPositionalArg()) { 3433 HandlePositionalNonpositionalArgs(getLocationOfByte(CS.getStart()), 3434 startSpecifier, specifierLen); 3435 return false; 3436 } 3437 } 3438 3439 // First check if the field width, precision, and conversion specifier 3440 // have matching data arguments. 3441 if (!HandleAmount(FS.getFieldWidth(), /* field width */ 0, 3442 startSpecifier, specifierLen)) { 3443 return false; 3444 } 3445 3446 if (!HandleAmount(FS.getPrecision(), /* precision */ 1, 3447 startSpecifier, specifierLen)) { 3448 return false; 3449 } 3450 3451 if (!CS.consumesDataArgument()) { 3452 // FIXME: Technically specifying a precision or field width here 3453 // makes no sense. Worth issuing a warning at some point. 3454 return true; 3455 } 3456 3457 // Consume the argument. 3458 unsigned argIndex = FS.getArgIndex(); 3459 if (argIndex < NumDataArgs) { 3460 // The check to see if the argIndex is valid will come later. 3461 // We set the bit here because we may exit early from this 3462 // function if we encounter some other error. 3463 CoveredArgs.set(argIndex); 3464 } 3465 3466 // FreeBSD kernel extensions. 3467 if (CS.getKind() == ConversionSpecifier::FreeBSDbArg || 3468 CS.getKind() == ConversionSpecifier::FreeBSDDArg) { 3469 // We need at least two arguments. 3470 if (!CheckNumArgs(FS, CS, startSpecifier, specifierLen, argIndex + 1)) 3471 return false; 3472 3473 // Claim the second argument. 3474 CoveredArgs.set(argIndex + 1); 3475 3476 // Type check the first argument (int for %b, pointer for %D) 3477 const Expr *Ex = getDataArg(argIndex); 3478 const analyze_printf::ArgType &AT = 3479 (CS.getKind() == ConversionSpecifier::FreeBSDbArg) ? 3480 ArgType(S.Context.IntTy) : ArgType::CPointerTy; 3481 if (AT.isValid() && !AT.matchesType(S.Context, Ex->getType())) 3482 EmitFormatDiagnostic( 3483 S.PDiag(diag::warn_format_conversion_argument_type_mismatch) 3484 << AT.getRepresentativeTypeName(S.Context) << Ex->getType() 3485 << false << Ex->getSourceRange(), 3486 Ex->getLocStart(), /*IsStringLocation*/false, 3487 getSpecifierRange(startSpecifier, specifierLen)); 3488 3489 // Type check the second argument (char * for both %b and %D) 3490 Ex = getDataArg(argIndex + 1); 3491 const analyze_printf::ArgType &AT2 = ArgType::CStrTy; 3492 if (AT2.isValid() && !AT2.matchesType(S.Context, Ex->getType())) 3493 EmitFormatDiagnostic( 3494 S.PDiag(diag::warn_format_conversion_argument_type_mismatch) 3495 << AT2.getRepresentativeTypeName(S.Context) << Ex->getType() 3496 << false << Ex->getSourceRange(), 3497 Ex->getLocStart(), /*IsStringLocation*/false, 3498 getSpecifierRange(startSpecifier, specifierLen)); 3499 3500 return true; 3501 } 3502 3503 // Check for using an Objective-C specific conversion specifier 3504 // in a non-ObjC literal. 3505 if (!ObjCContext && CS.isObjCArg()) { 3506 return HandleInvalidPrintfConversionSpecifier(FS, startSpecifier, 3507 specifierLen); 3508 } 3509 3510 // Check for invalid use of field width 3511 if (!FS.hasValidFieldWidth()) { 3512 HandleInvalidAmount(FS, FS.getFieldWidth(), /* field width */ 0, 3513 startSpecifier, specifierLen); 3514 } 3515 3516 // Check for invalid use of precision 3517 if (!FS.hasValidPrecision()) { 3518 HandleInvalidAmount(FS, FS.getPrecision(), /* precision */ 1, 3519 startSpecifier, specifierLen); 3520 } 3521 3522 // Check each flag does not conflict with any other component. 3523 if (!FS.hasValidThousandsGroupingPrefix()) 3524 HandleFlag(FS, FS.hasThousandsGrouping(), startSpecifier, specifierLen); 3525 if (!FS.hasValidLeadingZeros()) 3526 HandleFlag(FS, FS.hasLeadingZeros(), startSpecifier, specifierLen); 3527 if (!FS.hasValidPlusPrefix()) 3528 HandleFlag(FS, FS.hasPlusPrefix(), startSpecifier, specifierLen); 3529 if (!FS.hasValidSpacePrefix()) 3530 HandleFlag(FS, FS.hasSpacePrefix(), startSpecifier, specifierLen); 3531 if (!FS.hasValidAlternativeForm()) 3532 HandleFlag(FS, FS.hasAlternativeForm(), startSpecifier, specifierLen); 3533 if (!FS.hasValidLeftJustified()) 3534 HandleFlag(FS, FS.isLeftJustified(), startSpecifier, specifierLen); 3535 3536 // Check that flags are not ignored by another flag 3537 if (FS.hasSpacePrefix() && FS.hasPlusPrefix()) // ' ' ignored by '+' 3538 HandleIgnoredFlag(FS, FS.hasSpacePrefix(), FS.hasPlusPrefix(), 3539 startSpecifier, specifierLen); 3540 if (FS.hasLeadingZeros() && FS.isLeftJustified()) // '0' ignored by '-' 3541 HandleIgnoredFlag(FS, FS.hasLeadingZeros(), FS.isLeftJustified(), 3542 startSpecifier, specifierLen); 3543 3544 // Check the length modifier is valid with the given conversion specifier. 3545 if (!FS.hasValidLengthModifier(S.getASTContext().getTargetInfo())) 3546 HandleInvalidLengthModifier(FS, CS, startSpecifier, specifierLen, 3547 diag::warn_format_nonsensical_length); 3548 else if (!FS.hasStandardLengthModifier()) 3549 HandleNonStandardLengthModifier(FS, startSpecifier, specifierLen); 3550 else if (!FS.hasStandardLengthConversionCombination()) 3551 HandleInvalidLengthModifier(FS, CS, startSpecifier, specifierLen, 3552 diag::warn_format_non_standard_conversion_spec); 3553 3554 if (!FS.hasStandardConversionSpecifier(S.getLangOpts())) 3555 HandleNonStandardConversionSpecifier(CS, startSpecifier, specifierLen); 3556 3557 // The remaining checks depend on the data arguments. 3558 if (HasVAListArg) 3559 return true; 3560 3561 if (!CheckNumArgs(FS, CS, startSpecifier, specifierLen, argIndex)) 3562 return false; 3563 3564 const Expr *Arg = getDataArg(argIndex); 3565 if (!Arg) 3566 return true; 3567 3568 return checkFormatExpr(FS, startSpecifier, specifierLen, Arg); 3569 } 3570 3571 static bool requiresParensToAddCast(const Expr *E) { 3572 // FIXME: We should have a general way to reason about operator 3573 // precedence and whether parens are actually needed here. 3574 // Take care of a few common cases where they aren't. 3575 const Expr *Inside = E->IgnoreImpCasts(); 3576 if (const PseudoObjectExpr *POE = dyn_cast<PseudoObjectExpr>(Inside)) 3577 Inside = POE->getSyntacticForm()->IgnoreImpCasts(); 3578 3579 switch (Inside->getStmtClass()) { 3580 case Stmt::ArraySubscriptExprClass: 3581 case Stmt::CallExprClass: 3582 case Stmt::CharacterLiteralClass: 3583 case Stmt::CXXBoolLiteralExprClass: 3584 case Stmt::DeclRefExprClass: 3585 case Stmt::FloatingLiteralClass: 3586 case Stmt::IntegerLiteralClass: 3587 case Stmt::MemberExprClass: 3588 case Stmt::ObjCArrayLiteralClass: 3589 case Stmt::ObjCBoolLiteralExprClass: 3590 case Stmt::ObjCBoxedExprClass: 3591 case Stmt::ObjCDictionaryLiteralClass: 3592 case Stmt::ObjCEncodeExprClass: 3593 case Stmt::ObjCIvarRefExprClass: 3594 case Stmt::ObjCMessageExprClass: 3595 case Stmt::ObjCPropertyRefExprClass: 3596 case Stmt::ObjCStringLiteralClass: 3597 case Stmt::ObjCSubscriptRefExprClass: 3598 case Stmt::ParenExprClass: 3599 case Stmt::StringLiteralClass: 3600 case Stmt::UnaryOperatorClass: 3601 return false; 3602 default: 3603 return true; 3604 } 3605 } 3606 3607 static std::pair<QualType, StringRef> 3608 shouldNotPrintDirectly(const ASTContext &Context, 3609 QualType IntendedTy, 3610 const Expr *E) { 3611 // Use a 'while' to peel off layers of typedefs. 3612 QualType TyTy = IntendedTy; 3613 while (const TypedefType *UserTy = TyTy->getAs<TypedefType>()) { 3614 StringRef Name = UserTy->getDecl()->getName(); 3615 QualType CastTy = llvm::StringSwitch<QualType>(Name) 3616 .Case("NSInteger", Context.LongTy) 3617 .Case("NSUInteger", Context.UnsignedLongTy) 3618 .Case("SInt32", Context.IntTy) 3619 .Case("UInt32", Context.UnsignedIntTy) 3620 .Default(QualType()); 3621 3622 if (!CastTy.isNull()) 3623 return std::make_pair(CastTy, Name); 3624 3625 TyTy = UserTy->desugar(); 3626 } 3627 3628 // Strip parens if necessary. 3629 if (const ParenExpr *PE = dyn_cast<ParenExpr>(E)) 3630 return shouldNotPrintDirectly(Context, 3631 PE->getSubExpr()->getType(), 3632 PE->getSubExpr()); 3633 3634 // If this is a conditional expression, then its result type is constructed 3635 // via usual arithmetic conversions and thus there might be no necessary 3636 // typedef sugar there. Recurse to operands to check for NSInteger & 3637 // Co. usage condition. 3638 if (const ConditionalOperator *CO = dyn_cast<ConditionalOperator>(E)) { 3639 QualType TrueTy, FalseTy; 3640 StringRef TrueName, FalseName; 3641 3642 std::tie(TrueTy, TrueName) = 3643 shouldNotPrintDirectly(Context, 3644 CO->getTrueExpr()->getType(), 3645 CO->getTrueExpr()); 3646 std::tie(FalseTy, FalseName) = 3647 shouldNotPrintDirectly(Context, 3648 CO->getFalseExpr()->getType(), 3649 CO->getFalseExpr()); 3650 3651 if (TrueTy == FalseTy) 3652 return std::make_pair(TrueTy, TrueName); 3653 else if (TrueTy.isNull()) 3654 return std::make_pair(FalseTy, FalseName); 3655 else if (FalseTy.isNull()) 3656 return std::make_pair(TrueTy, TrueName); 3657 } 3658 3659 return std::make_pair(QualType(), StringRef()); 3660 } 3661 3662 bool 3663 CheckPrintfHandler::checkFormatExpr(const analyze_printf::PrintfSpecifier &FS, 3664 const char *StartSpecifier, 3665 unsigned SpecifierLen, 3666 const Expr *E) { 3667 using namespace analyze_format_string; 3668 using namespace analyze_printf; 3669 // Now type check the data expression that matches the 3670 // format specifier. 3671 const analyze_printf::ArgType &AT = FS.getArgType(S.Context, 3672 ObjCContext); 3673 if (!AT.isValid()) 3674 return true; 3675 3676 QualType ExprTy = E->getType(); 3677 while (const TypeOfExprType *TET = dyn_cast<TypeOfExprType>(ExprTy)) { 3678 ExprTy = TET->getUnderlyingExpr()->getType(); 3679 } 3680 3681 if (AT.matchesType(S.Context, ExprTy)) 3682 return true; 3683 3684 // Look through argument promotions for our error message's reported type. 3685 // This includes the integral and floating promotions, but excludes array 3686 // and function pointer decay; seeing that an argument intended to be a 3687 // string has type 'char [6]' is probably more confusing than 'char *'. 3688 if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) { 3689 if (ICE->getCastKind() == CK_IntegralCast || 3690 ICE->getCastKind() == CK_FloatingCast) { 3691 E = ICE->getSubExpr(); 3692 ExprTy = E->getType(); 3693 3694 // Check if we didn't match because of an implicit cast from a 'char' 3695 // or 'short' to an 'int'. This is done because printf is a varargs 3696 // function. 3697 if (ICE->getType() == S.Context.IntTy || 3698 ICE->getType() == S.Context.UnsignedIntTy) { 3699 // All further checking is done on the subexpression. 3700 if (AT.matchesType(S.Context, ExprTy)) 3701 return true; 3702 } 3703 } 3704 } else if (const CharacterLiteral *CL = dyn_cast<CharacterLiteral>(E)) { 3705 // Special case for 'a', which has type 'int' in C. 3706 // Note, however, that we do /not/ want to treat multibyte constants like 3707 // 'MooV' as characters! This form is deprecated but still exists. 3708 if (ExprTy == S.Context.IntTy) 3709 if (llvm::isUIntN(S.Context.getCharWidth(), CL->getValue())) 3710 ExprTy = S.Context.CharTy; 3711 } 3712 3713 // Look through enums to their underlying type. 3714 bool IsEnum = false; 3715 if (auto EnumTy = ExprTy->getAs<EnumType>()) { 3716 ExprTy = EnumTy->getDecl()->getIntegerType(); 3717 IsEnum = true; 3718 } 3719 3720 // %C in an Objective-C context prints a unichar, not a wchar_t. 3721 // If the argument is an integer of some kind, believe the %C and suggest 3722 // a cast instead of changing the conversion specifier. 3723 QualType IntendedTy = ExprTy; 3724 if (ObjCContext && 3725 FS.getConversionSpecifier().getKind() == ConversionSpecifier::CArg) { 3726 if (ExprTy->isIntegralOrUnscopedEnumerationType() && 3727 !ExprTy->isCharType()) { 3728 // 'unichar' is defined as a typedef of unsigned short, but we should 3729 // prefer using the typedef if it is visible. 3730 IntendedTy = S.Context.UnsignedShortTy; 3731 3732 // While we are here, check if the value is an IntegerLiteral that happens 3733 // to be within the valid range. 3734 if (const IntegerLiteral *IL = dyn_cast<IntegerLiteral>(E)) { 3735 const llvm::APInt &V = IL->getValue(); 3736 if (V.getActiveBits() <= S.Context.getTypeSize(IntendedTy)) 3737 return true; 3738 } 3739 3740 LookupResult Result(S, &S.Context.Idents.get("unichar"), E->getLocStart(), 3741 Sema::LookupOrdinaryName); 3742 if (S.LookupName(Result, S.getCurScope())) { 3743 NamedDecl *ND = Result.getFoundDecl(); 3744 if (TypedefNameDecl *TD = dyn_cast<TypedefNameDecl>(ND)) 3745 if (TD->getUnderlyingType() == IntendedTy) 3746 IntendedTy = S.Context.getTypedefType(TD); 3747 } 3748 } 3749 } 3750 3751 // Special-case some of Darwin's platform-independence types by suggesting 3752 // casts to primitive types that are known to be large enough. 3753 bool ShouldNotPrintDirectly = false; StringRef CastTyName; 3754 if (S.Context.getTargetInfo().getTriple().isOSDarwin()) { 3755 QualType CastTy; 3756 std::tie(CastTy, CastTyName) = shouldNotPrintDirectly(S.Context, IntendedTy, E); 3757 if (!CastTy.isNull()) { 3758 IntendedTy = CastTy; 3759 ShouldNotPrintDirectly = true; 3760 } 3761 } 3762 3763 // We may be able to offer a FixItHint if it is a supported type. 3764 PrintfSpecifier fixedFS = FS; 3765 bool success = fixedFS.fixType(IntendedTy, S.getLangOpts(), 3766 S.Context, ObjCContext); 3767 3768 if (success) { 3769 // Get the fix string from the fixed format specifier 3770 SmallString<16> buf; 3771 llvm::raw_svector_ostream os(buf); 3772 fixedFS.toString(os); 3773 3774 CharSourceRange SpecRange = getSpecifierRange(StartSpecifier, SpecifierLen); 3775 3776 if (IntendedTy == ExprTy && !ShouldNotPrintDirectly) { 3777 // In this case, the specifier is wrong and should be changed to match 3778 // the argument. 3779 EmitFormatDiagnostic( 3780 S.PDiag(diag::warn_format_conversion_argument_type_mismatch) 3781 << AT.getRepresentativeTypeName(S.Context) << IntendedTy << IsEnum 3782 << E->getSourceRange(), 3783 E->getLocStart(), 3784 /*IsStringLocation*/false, 3785 SpecRange, 3786 FixItHint::CreateReplacement(SpecRange, os.str())); 3787 3788 } else { 3789 // The canonical type for formatting this value is different from the 3790 // actual type of the expression. (This occurs, for example, with Darwin's 3791 // NSInteger on 32-bit platforms, where it is typedef'd as 'int', but 3792 // should be printed as 'long' for 64-bit compatibility.) 3793 // Rather than emitting a normal format/argument mismatch, we want to 3794 // add a cast to the recommended type (and correct the format string 3795 // if necessary). 3796 SmallString<16> CastBuf; 3797 llvm::raw_svector_ostream CastFix(CastBuf); 3798 CastFix << "("; 3799 IntendedTy.print(CastFix, S.Context.getPrintingPolicy()); 3800 CastFix << ")"; 3801 3802 SmallVector<FixItHint,4> Hints; 3803 if (!AT.matchesType(S.Context, IntendedTy)) 3804 Hints.push_back(FixItHint::CreateReplacement(SpecRange, os.str())); 3805 3806 if (const CStyleCastExpr *CCast = dyn_cast<CStyleCastExpr>(E)) { 3807 // If there's already a cast present, just replace it. 3808 SourceRange CastRange(CCast->getLParenLoc(), CCast->getRParenLoc()); 3809 Hints.push_back(FixItHint::CreateReplacement(CastRange, CastFix.str())); 3810 3811 } else if (!requiresParensToAddCast(E)) { 3812 // If the expression has high enough precedence, 3813 // just write the C-style cast. 3814 Hints.push_back(FixItHint::CreateInsertion(E->getLocStart(), 3815 CastFix.str())); 3816 } else { 3817 // Otherwise, add parens around the expression as well as the cast. 3818 CastFix << "("; 3819 Hints.push_back(FixItHint::CreateInsertion(E->getLocStart(), 3820 CastFix.str())); 3821 3822 SourceLocation After = S.getLocForEndOfToken(E->getLocEnd()); 3823 Hints.push_back(FixItHint::CreateInsertion(After, ")")); 3824 } 3825 3826 if (ShouldNotPrintDirectly) { 3827 // The expression has a type that should not be printed directly. 3828 // We extract the name from the typedef because we don't want to show 3829 // the underlying type in the diagnostic. 3830 StringRef Name; 3831 if (const TypedefType *TypedefTy = dyn_cast<TypedefType>(ExprTy)) 3832 Name = TypedefTy->getDecl()->getName(); 3833 else 3834 Name = CastTyName; 3835 EmitFormatDiagnostic(S.PDiag(diag::warn_format_argument_needs_cast) 3836 << Name << IntendedTy << IsEnum 3837 << E->getSourceRange(), 3838 E->getLocStart(), /*IsStringLocation=*/false, 3839 SpecRange, Hints); 3840 } else { 3841 // In this case, the expression could be printed using a different 3842 // specifier, but we've decided that the specifier is probably correct 3843 // and we should cast instead. Just use the normal warning message. 3844 EmitFormatDiagnostic( 3845 S.PDiag(diag::warn_format_conversion_argument_type_mismatch) 3846 << AT.getRepresentativeTypeName(S.Context) << ExprTy << IsEnum 3847 << E->getSourceRange(), 3848 E->getLocStart(), /*IsStringLocation*/false, 3849 SpecRange, Hints); 3850 } 3851 } 3852 } else { 3853 const CharSourceRange &CSR = getSpecifierRange(StartSpecifier, 3854 SpecifierLen); 3855 // Since the warning for passing non-POD types to variadic functions 3856 // was deferred until now, we emit a warning for non-POD 3857 // arguments here. 3858 switch (S.isValidVarArgType(ExprTy)) { 3859 case Sema::VAK_Valid: 3860 case Sema::VAK_ValidInCXX11: 3861 EmitFormatDiagnostic( 3862 S.PDiag(diag::warn_format_conversion_argument_type_mismatch) 3863 << AT.getRepresentativeTypeName(S.Context) << ExprTy << IsEnum 3864 << CSR 3865 << E->getSourceRange(), 3866 E->getLocStart(), /*IsStringLocation*/false, CSR); 3867 break; 3868 3869 case Sema::VAK_Undefined: 3870 case Sema::VAK_MSVCUndefined: 3871 EmitFormatDiagnostic( 3872 S.PDiag(diag::warn_non_pod_vararg_with_format_string) 3873 << S.getLangOpts().CPlusPlus11 3874 << ExprTy 3875 << CallType 3876 << AT.getRepresentativeTypeName(S.Context) 3877 << CSR 3878 << E->getSourceRange(), 3879 E->getLocStart(), /*IsStringLocation*/false, CSR); 3880 checkForCStrMembers(AT, E); 3881 break; 3882 3883 case Sema::VAK_Invalid: 3884 if (ExprTy->isObjCObjectType()) 3885 EmitFormatDiagnostic( 3886 S.PDiag(diag::err_cannot_pass_objc_interface_to_vararg_format) 3887 << S.getLangOpts().CPlusPlus11 3888 << ExprTy 3889 << CallType 3890 << AT.getRepresentativeTypeName(S.Context) 3891 << CSR 3892 << E->getSourceRange(), 3893 E->getLocStart(), /*IsStringLocation*/false, CSR); 3894 else 3895 // FIXME: If this is an initializer list, suggest removing the braces 3896 // or inserting a cast to the target type. 3897 S.Diag(E->getLocStart(), diag::err_cannot_pass_to_vararg_format) 3898 << isa<InitListExpr>(E) << ExprTy << CallType 3899 << AT.getRepresentativeTypeName(S.Context) 3900 << E->getSourceRange(); 3901 break; 3902 } 3903 3904 assert(FirstDataArg + FS.getArgIndex() < CheckedVarArgs.size() && 3905 "format string specifier index out of range"); 3906 CheckedVarArgs[FirstDataArg + FS.getArgIndex()] = true; 3907 } 3908 3909 return true; 3910 } 3911 3912 //===--- CHECK: Scanf format string checking ------------------------------===// 3913 3914 namespace { 3915 class CheckScanfHandler : public CheckFormatHandler { 3916 public: 3917 CheckScanfHandler(Sema &s, const StringLiteral *fexpr, 3918 const Expr *origFormatExpr, unsigned firstDataArg, 3919 unsigned numDataArgs, const char *beg, bool hasVAListArg, 3920 ArrayRef<const Expr *> Args, 3921 unsigned formatIdx, bool inFunctionCall, 3922 Sema::VariadicCallType CallType, 3923 llvm::SmallBitVector &CheckedVarArgs) 3924 : CheckFormatHandler(s, fexpr, origFormatExpr, firstDataArg, 3925 numDataArgs, beg, hasVAListArg, 3926 Args, formatIdx, inFunctionCall, CallType, 3927 CheckedVarArgs) 3928 {} 3929 3930 bool HandleScanfSpecifier(const analyze_scanf::ScanfSpecifier &FS, 3931 const char *startSpecifier, 3932 unsigned specifierLen) override; 3933 3934 bool HandleInvalidScanfConversionSpecifier( 3935 const analyze_scanf::ScanfSpecifier &FS, 3936 const char *startSpecifier, 3937 unsigned specifierLen) override; 3938 3939 void HandleIncompleteScanList(const char *start, const char *end) override; 3940 }; 3941 } 3942 3943 void CheckScanfHandler::HandleIncompleteScanList(const char *start, 3944 const char *end) { 3945 EmitFormatDiagnostic(S.PDiag(diag::warn_scanf_scanlist_incomplete), 3946 getLocationOfByte(end), /*IsStringLocation*/true, 3947 getSpecifierRange(start, end - start)); 3948 } 3949 3950 bool CheckScanfHandler::HandleInvalidScanfConversionSpecifier( 3951 const analyze_scanf::ScanfSpecifier &FS, 3952 const char *startSpecifier, 3953 unsigned specifierLen) { 3954 3955 const analyze_scanf::ScanfConversionSpecifier &CS = 3956 FS.getConversionSpecifier(); 3957 3958 return HandleInvalidConversionSpecifier(FS.getArgIndex(), 3959 getLocationOfByte(CS.getStart()), 3960 startSpecifier, specifierLen, 3961 CS.getStart(), CS.getLength()); 3962 } 3963 3964 bool CheckScanfHandler::HandleScanfSpecifier( 3965 const analyze_scanf::ScanfSpecifier &FS, 3966 const char *startSpecifier, 3967 unsigned specifierLen) { 3968 3969 using namespace analyze_scanf; 3970 using namespace analyze_format_string; 3971 3972 const ScanfConversionSpecifier &CS = FS.getConversionSpecifier(); 3973 3974 // Handle case where '%' and '*' don't consume an argument. These shouldn't 3975 // be used to decide if we are using positional arguments consistently. 3976 if (FS.consumesDataArgument()) { 3977 if (atFirstArg) { 3978 atFirstArg = false; 3979 usesPositionalArgs = FS.usesPositionalArg(); 3980 } 3981 else if (usesPositionalArgs != FS.usesPositionalArg()) { 3982 HandlePositionalNonpositionalArgs(getLocationOfByte(CS.getStart()), 3983 startSpecifier, specifierLen); 3984 return false; 3985 } 3986 } 3987 3988 // Check if the field with is non-zero. 3989 const OptionalAmount &Amt = FS.getFieldWidth(); 3990 if (Amt.getHowSpecified() == OptionalAmount::Constant) { 3991 if (Amt.getConstantAmount() == 0) { 3992 const CharSourceRange &R = getSpecifierRange(Amt.getStart(), 3993 Amt.getConstantLength()); 3994 EmitFormatDiagnostic(S.PDiag(diag::warn_scanf_nonzero_width), 3995 getLocationOfByte(Amt.getStart()), 3996 /*IsStringLocation*/true, R, 3997 FixItHint::CreateRemoval(R)); 3998 } 3999 } 4000 4001 if (!FS.consumesDataArgument()) { 4002 // FIXME: Technically specifying a precision or field width here 4003 // makes no sense. Worth issuing a warning at some point. 4004 return true; 4005 } 4006 4007 // Consume the argument. 4008 unsigned argIndex = FS.getArgIndex(); 4009 if (argIndex < NumDataArgs) { 4010 // The check to see if the argIndex is valid will come later. 4011 // We set the bit here because we may exit early from this 4012 // function if we encounter some other error. 4013 CoveredArgs.set(argIndex); 4014 } 4015 4016 // Check the length modifier is valid with the given conversion specifier. 4017 if (!FS.hasValidLengthModifier(S.getASTContext().getTargetInfo())) 4018 HandleInvalidLengthModifier(FS, CS, startSpecifier, specifierLen, 4019 diag::warn_format_nonsensical_length); 4020 else if (!FS.hasStandardLengthModifier()) 4021 HandleNonStandardLengthModifier(FS, startSpecifier, specifierLen); 4022 else if (!FS.hasStandardLengthConversionCombination()) 4023 HandleInvalidLengthModifier(FS, CS, startSpecifier, specifierLen, 4024 diag::warn_format_non_standard_conversion_spec); 4025 4026 if (!FS.hasStandardConversionSpecifier(S.getLangOpts())) 4027 HandleNonStandardConversionSpecifier(CS, startSpecifier, specifierLen); 4028 4029 // The remaining checks depend on the data arguments. 4030 if (HasVAListArg) 4031 return true; 4032 4033 if (!CheckNumArgs(FS, CS, startSpecifier, specifierLen, argIndex)) 4034 return false; 4035 4036 // Check that the argument type matches the format specifier. 4037 const Expr *Ex = getDataArg(argIndex); 4038 if (!Ex) 4039 return true; 4040 4041 const analyze_format_string::ArgType &AT = FS.getArgType(S.Context); 4042 if (AT.isValid() && !AT.matchesType(S.Context, Ex->getType())) { 4043 ScanfSpecifier fixedFS = FS; 4044 bool success = fixedFS.fixType(Ex->getType(), 4045 Ex->IgnoreImpCasts()->getType(), 4046 S.getLangOpts(), S.Context); 4047 4048 if (success) { 4049 // Get the fix string from the fixed format specifier. 4050 SmallString<128> buf; 4051 llvm::raw_svector_ostream os(buf); 4052 fixedFS.toString(os); 4053 4054 EmitFormatDiagnostic( 4055 S.PDiag(diag::warn_format_conversion_argument_type_mismatch) 4056 << AT.getRepresentativeTypeName(S.Context) << Ex->getType() << false 4057 << Ex->getSourceRange(), 4058 Ex->getLocStart(), 4059 /*IsStringLocation*/false, 4060 getSpecifierRange(startSpecifier, specifierLen), 4061 FixItHint::CreateReplacement( 4062 getSpecifierRange(startSpecifier, specifierLen), 4063 os.str())); 4064 } else { 4065 EmitFormatDiagnostic( 4066 S.PDiag(diag::warn_format_conversion_argument_type_mismatch) 4067 << AT.getRepresentativeTypeName(S.Context) << Ex->getType() << false 4068 << Ex->getSourceRange(), 4069 Ex->getLocStart(), 4070 /*IsStringLocation*/false, 4071 getSpecifierRange(startSpecifier, specifierLen)); 4072 } 4073 } 4074 4075 return true; 4076 } 4077 4078 void Sema::CheckFormatString(const StringLiteral *FExpr, 4079 const Expr *OrigFormatExpr, 4080 ArrayRef<const Expr *> Args, 4081 bool HasVAListArg, unsigned format_idx, 4082 unsigned firstDataArg, FormatStringType Type, 4083 bool inFunctionCall, VariadicCallType CallType, 4084 llvm::SmallBitVector &CheckedVarArgs) { 4085 4086 // CHECK: is the format string a wide literal? 4087 if (!FExpr->isAscii() && !FExpr->isUTF8()) { 4088 CheckFormatHandler::EmitFormatDiagnostic( 4089 *this, inFunctionCall, Args[format_idx], 4090 PDiag(diag::warn_format_string_is_wide_literal), FExpr->getLocStart(), 4091 /*IsStringLocation*/true, OrigFormatExpr->getSourceRange()); 4092 return; 4093 } 4094 4095 // Str - The format string. NOTE: this is NOT null-terminated! 4096 StringRef StrRef = FExpr->getString(); 4097 const char *Str = StrRef.data(); 4098 // Account for cases where the string literal is truncated in a declaration. 4099 const ConstantArrayType *T = Context.getAsConstantArrayType(FExpr->getType()); 4100 assert(T && "String literal not of constant array type!"); 4101 size_t TypeSize = T->getSize().getZExtValue(); 4102 size_t StrLen = std::min(std::max(TypeSize, size_t(1)) - 1, StrRef.size()); 4103 const unsigned numDataArgs = Args.size() - firstDataArg; 4104 4105 // Emit a warning if the string literal is truncated and does not contain an 4106 // embedded null character. 4107 if (TypeSize <= StrRef.size() && 4108 StrRef.substr(0, TypeSize).find('\0') == StringRef::npos) { 4109 CheckFormatHandler::EmitFormatDiagnostic( 4110 *this, inFunctionCall, Args[format_idx], 4111 PDiag(diag::warn_printf_format_string_not_null_terminated), 4112 FExpr->getLocStart(), 4113 /*IsStringLocation=*/true, OrigFormatExpr->getSourceRange()); 4114 return; 4115 } 4116 4117 // CHECK: empty format string? 4118 if (StrLen == 0 && numDataArgs > 0) { 4119 CheckFormatHandler::EmitFormatDiagnostic( 4120 *this, inFunctionCall, Args[format_idx], 4121 PDiag(diag::warn_empty_format_string), FExpr->getLocStart(), 4122 /*IsStringLocation*/true, OrigFormatExpr->getSourceRange()); 4123 return; 4124 } 4125 4126 if (Type == FST_Printf || Type == FST_NSString || 4127 Type == FST_FreeBSDKPrintf || Type == FST_OSTrace) { 4128 CheckPrintfHandler H(*this, FExpr, OrigFormatExpr, firstDataArg, 4129 numDataArgs, (Type == FST_NSString || Type == FST_OSTrace), 4130 Str, HasVAListArg, Args, format_idx, 4131 inFunctionCall, CallType, CheckedVarArgs); 4132 4133 if (!analyze_format_string::ParsePrintfString(H, Str, Str + StrLen, 4134 getLangOpts(), 4135 Context.getTargetInfo(), 4136 Type == FST_FreeBSDKPrintf)) 4137 H.DoneProcessing(); 4138 } else if (Type == FST_Scanf) { 4139 CheckScanfHandler H(*this, FExpr, OrigFormatExpr, firstDataArg, numDataArgs, 4140 Str, HasVAListArg, Args, format_idx, 4141 inFunctionCall, CallType, CheckedVarArgs); 4142 4143 if (!analyze_format_string::ParseScanfString(H, Str, Str + StrLen, 4144 getLangOpts(), 4145 Context.getTargetInfo())) 4146 H.DoneProcessing(); 4147 } // TODO: handle other formats 4148 } 4149 4150 bool Sema::FormatStringHasSArg(const StringLiteral *FExpr) { 4151 // Str - The format string. NOTE: this is NOT null-terminated! 4152 StringRef StrRef = FExpr->getString(); 4153 const char *Str = StrRef.data(); 4154 // Account for cases where the string literal is truncated in a declaration. 4155 const ConstantArrayType *T = Context.getAsConstantArrayType(FExpr->getType()); 4156 assert(T && "String literal not of constant array type!"); 4157 size_t TypeSize = T->getSize().getZExtValue(); 4158 size_t StrLen = std::min(std::max(TypeSize, size_t(1)) - 1, StrRef.size()); 4159 return analyze_format_string::ParseFormatStringHasSArg(Str, Str + StrLen, 4160 getLangOpts(), 4161 Context.getTargetInfo()); 4162 } 4163 4164 //===--- CHECK: Warn on use of wrong absolute value function. -------------===// 4165 4166 // Returns the related absolute value function that is larger, of 0 if one 4167 // does not exist. 4168 static unsigned getLargerAbsoluteValueFunction(unsigned AbsFunction) { 4169 switch (AbsFunction) { 4170 default: 4171 return 0; 4172 4173 case Builtin::BI__builtin_abs: 4174 return Builtin::BI__builtin_labs; 4175 case Builtin::BI__builtin_labs: 4176 return Builtin::BI__builtin_llabs; 4177 case Builtin::BI__builtin_llabs: 4178 return 0; 4179 4180 case Builtin::BI__builtin_fabsf: 4181 return Builtin::BI__builtin_fabs; 4182 case Builtin::BI__builtin_fabs: 4183 return Builtin::BI__builtin_fabsl; 4184 case Builtin::BI__builtin_fabsl: 4185 return 0; 4186 4187 case Builtin::BI__builtin_cabsf: 4188 return Builtin::BI__builtin_cabs; 4189 case Builtin::BI__builtin_cabs: 4190 return Builtin::BI__builtin_cabsl; 4191 case Builtin::BI__builtin_cabsl: 4192 return 0; 4193 4194 case Builtin::BIabs: 4195 return Builtin::BIlabs; 4196 case Builtin::BIlabs: 4197 return Builtin::BIllabs; 4198 case Builtin::BIllabs: 4199 return 0; 4200 4201 case Builtin::BIfabsf: 4202 return Builtin::BIfabs; 4203 case Builtin::BIfabs: 4204 return Builtin::BIfabsl; 4205 case Builtin::BIfabsl: 4206 return 0; 4207 4208 case Builtin::BIcabsf: 4209 return Builtin::BIcabs; 4210 case Builtin::BIcabs: 4211 return Builtin::BIcabsl; 4212 case Builtin::BIcabsl: 4213 return 0; 4214 } 4215 } 4216 4217 // Returns the argument type of the absolute value function. 4218 static QualType getAbsoluteValueArgumentType(ASTContext &Context, 4219 unsigned AbsType) { 4220 if (AbsType == 0) 4221 return QualType(); 4222 4223 ASTContext::GetBuiltinTypeError Error = ASTContext::GE_None; 4224 QualType BuiltinType = Context.GetBuiltinType(AbsType, Error); 4225 if (Error != ASTContext::GE_None) 4226 return QualType(); 4227 4228 const FunctionProtoType *FT = BuiltinType->getAs<FunctionProtoType>(); 4229 if (!FT) 4230 return QualType(); 4231 4232 if (FT->getNumParams() != 1) 4233 return QualType(); 4234 4235 return FT->getParamType(0); 4236 } 4237 4238 // Returns the best absolute value function, or zero, based on type and 4239 // current absolute value function. 4240 static unsigned getBestAbsFunction(ASTContext &Context, QualType ArgType, 4241 unsigned AbsFunctionKind) { 4242 unsigned BestKind = 0; 4243 uint64_t ArgSize = Context.getTypeSize(ArgType); 4244 for (unsigned Kind = AbsFunctionKind; Kind != 0; 4245 Kind = getLargerAbsoluteValueFunction(Kind)) { 4246 QualType ParamType = getAbsoluteValueArgumentType(Context, Kind); 4247 if (Context.getTypeSize(ParamType) >= ArgSize) { 4248 if (BestKind == 0) 4249 BestKind = Kind; 4250 else if (Context.hasSameType(ParamType, ArgType)) { 4251 BestKind = Kind; 4252 break; 4253 } 4254 } 4255 } 4256 return BestKind; 4257 } 4258 4259 enum AbsoluteValueKind { 4260 AVK_Integer, 4261 AVK_Floating, 4262 AVK_Complex 4263 }; 4264 4265 static AbsoluteValueKind getAbsoluteValueKind(QualType T) { 4266 if (T->isIntegralOrEnumerationType()) 4267 return AVK_Integer; 4268 if (T->isRealFloatingType()) 4269 return AVK_Floating; 4270 if (T->isAnyComplexType()) 4271 return AVK_Complex; 4272 4273 llvm_unreachable("Type not integer, floating, or complex"); 4274 } 4275 4276 // Changes the absolute value function to a different type. Preserves whether 4277 // the function is a builtin. 4278 static unsigned changeAbsFunction(unsigned AbsKind, 4279 AbsoluteValueKind ValueKind) { 4280 switch (ValueKind) { 4281 case AVK_Integer: 4282 switch (AbsKind) { 4283 default: 4284 return 0; 4285 case Builtin::BI__builtin_fabsf: 4286 case Builtin::BI__builtin_fabs: 4287 case Builtin::BI__builtin_fabsl: 4288 case Builtin::BI__builtin_cabsf: 4289 case Builtin::BI__builtin_cabs: 4290 case Builtin::BI__builtin_cabsl: 4291 return Builtin::BI__builtin_abs; 4292 case Builtin::BIfabsf: 4293 case Builtin::BIfabs: 4294 case Builtin::BIfabsl: 4295 case Builtin::BIcabsf: 4296 case Builtin::BIcabs: 4297 case Builtin::BIcabsl: 4298 return Builtin::BIabs; 4299 } 4300 case AVK_Floating: 4301 switch (AbsKind) { 4302 default: 4303 return 0; 4304 case Builtin::BI__builtin_abs: 4305 case Builtin::BI__builtin_labs: 4306 case Builtin::BI__builtin_llabs: 4307 case Builtin::BI__builtin_cabsf: 4308 case Builtin::BI__builtin_cabs: 4309 case Builtin::BI__builtin_cabsl: 4310 return Builtin::BI__builtin_fabsf; 4311 case Builtin::BIabs: 4312 case Builtin::BIlabs: 4313 case Builtin::BIllabs: 4314 case Builtin::BIcabsf: 4315 case Builtin::BIcabs: 4316 case Builtin::BIcabsl: 4317 return Builtin::BIfabsf; 4318 } 4319 case AVK_Complex: 4320 switch (AbsKind) { 4321 default: 4322 return 0; 4323 case Builtin::BI__builtin_abs: 4324 case Builtin::BI__builtin_labs: 4325 case Builtin::BI__builtin_llabs: 4326 case Builtin::BI__builtin_fabsf: 4327 case Builtin::BI__builtin_fabs: 4328 case Builtin::BI__builtin_fabsl: 4329 return Builtin::BI__builtin_cabsf; 4330 case Builtin::BIabs: 4331 case Builtin::BIlabs: 4332 case Builtin::BIllabs: 4333 case Builtin::BIfabsf: 4334 case Builtin::BIfabs: 4335 case Builtin::BIfabsl: 4336 return Builtin::BIcabsf; 4337 } 4338 } 4339 llvm_unreachable("Unable to convert function"); 4340 } 4341 4342 static unsigned getAbsoluteValueFunctionKind(const FunctionDecl *FDecl) { 4343 const IdentifierInfo *FnInfo = FDecl->getIdentifier(); 4344 if (!FnInfo) 4345 return 0; 4346 4347 switch (FDecl->getBuiltinID()) { 4348 default: 4349 return 0; 4350 case Builtin::BI__builtin_abs: 4351 case Builtin::BI__builtin_fabs: 4352 case Builtin::BI__builtin_fabsf: 4353 case Builtin::BI__builtin_fabsl: 4354 case Builtin::BI__builtin_labs: 4355 case Builtin::BI__builtin_llabs: 4356 case Builtin::BI__builtin_cabs: 4357 case Builtin::BI__builtin_cabsf: 4358 case Builtin::BI__builtin_cabsl: 4359 case Builtin::BIabs: 4360 case Builtin::BIlabs: 4361 case Builtin::BIllabs: 4362 case Builtin::BIfabs: 4363 case Builtin::BIfabsf: 4364 case Builtin::BIfabsl: 4365 case Builtin::BIcabs: 4366 case Builtin::BIcabsf: 4367 case Builtin::BIcabsl: 4368 return FDecl->getBuiltinID(); 4369 } 4370 llvm_unreachable("Unknown Builtin type"); 4371 } 4372 4373 // If the replacement is valid, emit a note with replacement function. 4374 // Additionally, suggest including the proper header if not already included. 4375 static void emitReplacement(Sema &S, SourceLocation Loc, SourceRange Range, 4376 unsigned AbsKind, QualType ArgType) { 4377 bool EmitHeaderHint = true; 4378 const char *HeaderName = nullptr; 4379 const char *FunctionName = nullptr; 4380 if (S.getLangOpts().CPlusPlus && !ArgType->isAnyComplexType()) { 4381 FunctionName = "std::abs"; 4382 if (ArgType->isIntegralOrEnumerationType()) { 4383 HeaderName = "cstdlib"; 4384 } else if (ArgType->isRealFloatingType()) { 4385 HeaderName = "cmath"; 4386 } else { 4387 llvm_unreachable("Invalid Type"); 4388 } 4389 4390 // Lookup all std::abs 4391 if (NamespaceDecl *Std = S.getStdNamespace()) { 4392 LookupResult R(S, &S.Context.Idents.get("abs"), Loc, Sema::LookupAnyName); 4393 R.suppressDiagnostics(); 4394 S.LookupQualifiedName(R, Std); 4395 4396 for (const auto *I : R) { 4397 const FunctionDecl *FDecl = nullptr; 4398 if (const UsingShadowDecl *UsingD = dyn_cast<UsingShadowDecl>(I)) { 4399 FDecl = dyn_cast<FunctionDecl>(UsingD->getTargetDecl()); 4400 } else { 4401 FDecl = dyn_cast<FunctionDecl>(I); 4402 } 4403 if (!FDecl) 4404 continue; 4405 4406 // Found std::abs(), check that they are the right ones. 4407 if (FDecl->getNumParams() != 1) 4408 continue; 4409 4410 // Check that the parameter type can handle the argument. 4411 QualType ParamType = FDecl->getParamDecl(0)->getType(); 4412 if (getAbsoluteValueKind(ArgType) == getAbsoluteValueKind(ParamType) && 4413 S.Context.getTypeSize(ArgType) <= 4414 S.Context.getTypeSize(ParamType)) { 4415 // Found a function, don't need the header hint. 4416 EmitHeaderHint = false; 4417 break; 4418 } 4419 } 4420 } 4421 } else { 4422 FunctionName = S.Context.BuiltinInfo.GetName(AbsKind); 4423 HeaderName = S.Context.BuiltinInfo.getHeaderName(AbsKind); 4424 4425 if (HeaderName) { 4426 DeclarationName DN(&S.Context.Idents.get(FunctionName)); 4427 LookupResult R(S, DN, Loc, Sema::LookupAnyName); 4428 R.suppressDiagnostics(); 4429 S.LookupName(R, S.getCurScope()); 4430 4431 if (R.isSingleResult()) { 4432 FunctionDecl *FD = dyn_cast<FunctionDecl>(R.getFoundDecl()); 4433 if (FD && FD->getBuiltinID() == AbsKind) { 4434 EmitHeaderHint = false; 4435 } else { 4436 return; 4437 } 4438 } else if (!R.empty()) { 4439 return; 4440 } 4441 } 4442 } 4443 4444 S.Diag(Loc, diag::note_replace_abs_function) 4445 << FunctionName << FixItHint::CreateReplacement(Range, FunctionName); 4446 4447 if (!HeaderName) 4448 return; 4449 4450 if (!EmitHeaderHint) 4451 return; 4452 4453 S.Diag(Loc, diag::note_include_header_or_declare) << HeaderName 4454 << FunctionName; 4455 } 4456 4457 static bool IsFunctionStdAbs(const FunctionDecl *FDecl) { 4458 if (!FDecl) 4459 return false; 4460 4461 if (!FDecl->getIdentifier() || !FDecl->getIdentifier()->isStr("abs")) 4462 return false; 4463 4464 const NamespaceDecl *ND = dyn_cast<NamespaceDecl>(FDecl->getDeclContext()); 4465 4466 while (ND && ND->isInlineNamespace()) { 4467 ND = dyn_cast<NamespaceDecl>(ND->getDeclContext()); 4468 } 4469 4470 if (!ND || !ND->getIdentifier() || !ND->getIdentifier()->isStr("std")) 4471 return false; 4472 4473 if (!isa<TranslationUnitDecl>(ND->getDeclContext())) 4474 return false; 4475 4476 return true; 4477 } 4478 4479 // Warn when using the wrong abs() function. 4480 void Sema::CheckAbsoluteValueFunction(const CallExpr *Call, 4481 const FunctionDecl *FDecl, 4482 IdentifierInfo *FnInfo) { 4483 if (Call->getNumArgs() != 1) 4484 return; 4485 4486 unsigned AbsKind = getAbsoluteValueFunctionKind(FDecl); 4487 bool IsStdAbs = IsFunctionStdAbs(FDecl); 4488 if (AbsKind == 0 && !IsStdAbs) 4489 return; 4490 4491 QualType ArgType = Call->getArg(0)->IgnoreParenImpCasts()->getType(); 4492 QualType ParamType = Call->getArg(0)->getType(); 4493 4494 // Unsigned types cannot be negative. Suggest removing the absolute value 4495 // function call. 4496 if (ArgType->isUnsignedIntegerType()) { 4497 const char *FunctionName = 4498 IsStdAbs ? "std::abs" : Context.BuiltinInfo.GetName(AbsKind); 4499 Diag(Call->getExprLoc(), diag::warn_unsigned_abs) << ArgType << ParamType; 4500 Diag(Call->getExprLoc(), diag::note_remove_abs) 4501 << FunctionName 4502 << FixItHint::CreateRemoval(Call->getCallee()->getSourceRange()); 4503 return; 4504 } 4505 4506 // std::abs has overloads which prevent most of the absolute value problems 4507 // from occurring. 4508 if (IsStdAbs) 4509 return; 4510 4511 AbsoluteValueKind ArgValueKind = getAbsoluteValueKind(ArgType); 4512 AbsoluteValueKind ParamValueKind = getAbsoluteValueKind(ParamType); 4513 4514 // The argument and parameter are the same kind. Check if they are the right 4515 // size. 4516 if (ArgValueKind == ParamValueKind) { 4517 if (Context.getTypeSize(ArgType) <= Context.getTypeSize(ParamType)) 4518 return; 4519 4520 unsigned NewAbsKind = getBestAbsFunction(Context, ArgType, AbsKind); 4521 Diag(Call->getExprLoc(), diag::warn_abs_too_small) 4522 << FDecl << ArgType << ParamType; 4523 4524 if (NewAbsKind == 0) 4525 return; 4526 4527 emitReplacement(*this, Call->getExprLoc(), 4528 Call->getCallee()->getSourceRange(), NewAbsKind, ArgType); 4529 return; 4530 } 4531 4532 // ArgValueKind != ParamValueKind 4533 // The wrong type of absolute value function was used. Attempt to find the 4534 // proper one. 4535 unsigned NewAbsKind = changeAbsFunction(AbsKind, ArgValueKind); 4536 NewAbsKind = getBestAbsFunction(Context, ArgType, NewAbsKind); 4537 if (NewAbsKind == 0) 4538 return; 4539 4540 Diag(Call->getExprLoc(), diag::warn_wrong_absolute_value_type) 4541 << FDecl << ParamValueKind << ArgValueKind; 4542 4543 emitReplacement(*this, Call->getExprLoc(), 4544 Call->getCallee()->getSourceRange(), NewAbsKind, ArgType); 4545 return; 4546 } 4547 4548 //===--- CHECK: Standard memory functions ---------------------------------===// 4549 4550 /// \brief Takes the expression passed to the size_t parameter of functions 4551 /// such as memcmp, strncat, etc and warns if it's a comparison. 4552 /// 4553 /// This is to catch typos like `if (memcmp(&a, &b, sizeof(a) > 0))`. 4554 static bool CheckMemorySizeofForComparison(Sema &S, const Expr *E, 4555 IdentifierInfo *FnName, 4556 SourceLocation FnLoc, 4557 SourceLocation RParenLoc) { 4558 const BinaryOperator *Size = dyn_cast<BinaryOperator>(E); 4559 if (!Size) 4560 return false; 4561 4562 // if E is binop and op is >, <, >=, <=, ==, &&, ||: 4563 if (!Size->isComparisonOp() && !Size->isEqualityOp() && !Size->isLogicalOp()) 4564 return false; 4565 4566 SourceRange SizeRange = Size->getSourceRange(); 4567 S.Diag(Size->getOperatorLoc(), diag::warn_memsize_comparison) 4568 << SizeRange << FnName; 4569 S.Diag(FnLoc, diag::note_memsize_comparison_paren) 4570 << FnName << FixItHint::CreateInsertion( 4571 S.getLocForEndOfToken(Size->getLHS()->getLocEnd()), ")") 4572 << FixItHint::CreateRemoval(RParenLoc); 4573 S.Diag(SizeRange.getBegin(), diag::note_memsize_comparison_cast_silence) 4574 << FixItHint::CreateInsertion(SizeRange.getBegin(), "(size_t)(") 4575 << FixItHint::CreateInsertion(S.getLocForEndOfToken(SizeRange.getEnd()), 4576 ")"); 4577 4578 return true; 4579 } 4580 4581 /// \brief Determine whether the given type is or contains a dynamic class type 4582 /// (e.g., whether it has a vtable). 4583 static const CXXRecordDecl *getContainedDynamicClass(QualType T, 4584 bool &IsContained) { 4585 // Look through array types while ignoring qualifiers. 4586 const Type *Ty = T->getBaseElementTypeUnsafe(); 4587 IsContained = false; 4588 4589 const CXXRecordDecl *RD = Ty->getAsCXXRecordDecl(); 4590 RD = RD ? RD->getDefinition() : nullptr; 4591 if (!RD) 4592 return nullptr; 4593 4594 if (RD->isDynamicClass()) 4595 return RD; 4596 4597 // Check all the fields. If any bases were dynamic, the class is dynamic. 4598 // It's impossible for a class to transitively contain itself by value, so 4599 // infinite recursion is impossible. 4600 for (auto *FD : RD->fields()) { 4601 bool SubContained; 4602 if (const CXXRecordDecl *ContainedRD = 4603 getContainedDynamicClass(FD->getType(), SubContained)) { 4604 IsContained = true; 4605 return ContainedRD; 4606 } 4607 } 4608 4609 return nullptr; 4610 } 4611 4612 /// \brief If E is a sizeof expression, returns its argument expression, 4613 /// otherwise returns NULL. 4614 static const Expr *getSizeOfExprArg(const Expr* E) { 4615 if (const UnaryExprOrTypeTraitExpr *SizeOf = 4616 dyn_cast<UnaryExprOrTypeTraitExpr>(E)) 4617 if (SizeOf->getKind() == clang::UETT_SizeOf && !SizeOf->isArgumentType()) 4618 return SizeOf->getArgumentExpr()->IgnoreParenImpCasts(); 4619 4620 return nullptr; 4621 } 4622 4623 /// \brief If E is a sizeof expression, returns its argument type. 4624 static QualType getSizeOfArgType(const Expr* E) { 4625 if (const UnaryExprOrTypeTraitExpr *SizeOf = 4626 dyn_cast<UnaryExprOrTypeTraitExpr>(E)) 4627 if (SizeOf->getKind() == clang::UETT_SizeOf) 4628 return SizeOf->getTypeOfArgument(); 4629 4630 return QualType(); 4631 } 4632 4633 /// \brief Check for dangerous or invalid arguments to memset(). 4634 /// 4635 /// This issues warnings on known problematic, dangerous or unspecified 4636 /// arguments to the standard 'memset', 'memcpy', 'memmove', and 'memcmp' 4637 /// function calls. 4638 /// 4639 /// \param Call The call expression to diagnose. 4640 void Sema::CheckMemaccessArguments(const CallExpr *Call, 4641 unsigned BId, 4642 IdentifierInfo *FnName) { 4643 assert(BId != 0); 4644 4645 // It is possible to have a non-standard definition of memset. Validate 4646 // we have enough arguments, and if not, abort further checking. 4647 unsigned ExpectedNumArgs = (BId == Builtin::BIstrndup ? 2 : 3); 4648 if (Call->getNumArgs() < ExpectedNumArgs) 4649 return; 4650 4651 unsigned LastArg = (BId == Builtin::BImemset || 4652 BId == Builtin::BIstrndup ? 1 : 2); 4653 unsigned LenArg = (BId == Builtin::BIstrndup ? 1 : 2); 4654 const Expr *LenExpr = Call->getArg(LenArg)->IgnoreParenImpCasts(); 4655 4656 if (CheckMemorySizeofForComparison(*this, LenExpr, FnName, 4657 Call->getLocStart(), Call->getRParenLoc())) 4658 return; 4659 4660 // We have special checking when the length is a sizeof expression. 4661 QualType SizeOfArgTy = getSizeOfArgType(LenExpr); 4662 const Expr *SizeOfArg = getSizeOfExprArg(LenExpr); 4663 llvm::FoldingSetNodeID SizeOfArgID; 4664 4665 for (unsigned ArgIdx = 0; ArgIdx != LastArg; ++ArgIdx) { 4666 const Expr *Dest = Call->getArg(ArgIdx)->IgnoreParenImpCasts(); 4667 SourceRange ArgRange = Call->getArg(ArgIdx)->getSourceRange(); 4668 4669 QualType DestTy = Dest->getType(); 4670 if (const PointerType *DestPtrTy = DestTy->getAs<PointerType>()) { 4671 QualType PointeeTy = DestPtrTy->getPointeeType(); 4672 4673 // Never warn about void type pointers. This can be used to suppress 4674 // false positives. 4675 if (PointeeTy->isVoidType()) 4676 continue; 4677 4678 // Catch "memset(p, 0, sizeof(p))" -- needs to be sizeof(*p). Do this by 4679 // actually comparing the expressions for equality. Because computing the 4680 // expression IDs can be expensive, we only do this if the diagnostic is 4681 // enabled. 4682 if (SizeOfArg && 4683 !Diags.isIgnored(diag::warn_sizeof_pointer_expr_memaccess, 4684 SizeOfArg->getExprLoc())) { 4685 // We only compute IDs for expressions if the warning is enabled, and 4686 // cache the sizeof arg's ID. 4687 if (SizeOfArgID == llvm::FoldingSetNodeID()) 4688 SizeOfArg->Profile(SizeOfArgID, Context, true); 4689 llvm::FoldingSetNodeID DestID; 4690 Dest->Profile(DestID, Context, true); 4691 if (DestID == SizeOfArgID) { 4692 // TODO: For strncpy() and friends, this could suggest sizeof(dst) 4693 // over sizeof(src) as well. 4694 unsigned ActionIdx = 0; // Default is to suggest dereferencing. 4695 StringRef ReadableName = FnName->getName(); 4696 4697 if (const UnaryOperator *UnaryOp = dyn_cast<UnaryOperator>(Dest)) 4698 if (UnaryOp->getOpcode() == UO_AddrOf) 4699 ActionIdx = 1; // If its an address-of operator, just remove it. 4700 if (!PointeeTy->isIncompleteType() && 4701 (Context.getTypeSize(PointeeTy) == Context.getCharWidth())) 4702 ActionIdx = 2; // If the pointee's size is sizeof(char), 4703 // suggest an explicit length. 4704 4705 // If the function is defined as a builtin macro, do not show macro 4706 // expansion. 4707 SourceLocation SL = SizeOfArg->getExprLoc(); 4708 SourceRange DSR = Dest->getSourceRange(); 4709 SourceRange SSR = SizeOfArg->getSourceRange(); 4710 SourceManager &SM = getSourceManager(); 4711 4712 if (SM.isMacroArgExpansion(SL)) { 4713 ReadableName = Lexer::getImmediateMacroName(SL, SM, LangOpts); 4714 SL = SM.getSpellingLoc(SL); 4715 DSR = SourceRange(SM.getSpellingLoc(DSR.getBegin()), 4716 SM.getSpellingLoc(DSR.getEnd())); 4717 SSR = SourceRange(SM.getSpellingLoc(SSR.getBegin()), 4718 SM.getSpellingLoc(SSR.getEnd())); 4719 } 4720 4721 DiagRuntimeBehavior(SL, SizeOfArg, 4722 PDiag(diag::warn_sizeof_pointer_expr_memaccess) 4723 << ReadableName 4724 << PointeeTy 4725 << DestTy 4726 << DSR 4727 << SSR); 4728 DiagRuntimeBehavior(SL, SizeOfArg, 4729 PDiag(diag::warn_sizeof_pointer_expr_memaccess_note) 4730 << ActionIdx 4731 << SSR); 4732 4733 break; 4734 } 4735 } 4736 4737 // Also check for cases where the sizeof argument is the exact same 4738 // type as the memory argument, and where it points to a user-defined 4739 // record type. 4740 if (SizeOfArgTy != QualType()) { 4741 if (PointeeTy->isRecordType() && 4742 Context.typesAreCompatible(SizeOfArgTy, DestTy)) { 4743 DiagRuntimeBehavior(LenExpr->getExprLoc(), Dest, 4744 PDiag(diag::warn_sizeof_pointer_type_memaccess) 4745 << FnName << SizeOfArgTy << ArgIdx 4746 << PointeeTy << Dest->getSourceRange() 4747 << LenExpr->getSourceRange()); 4748 break; 4749 } 4750 } 4751 4752 // Always complain about dynamic classes. 4753 bool IsContained; 4754 if (const CXXRecordDecl *ContainedRD = 4755 getContainedDynamicClass(PointeeTy, IsContained)) { 4756 4757 unsigned OperationType = 0; 4758 // "overwritten" if we're warning about the destination for any call 4759 // but memcmp; otherwise a verb appropriate to the call. 4760 if (ArgIdx != 0 || BId == Builtin::BImemcmp) { 4761 if (BId == Builtin::BImemcpy) 4762 OperationType = 1; 4763 else if(BId == Builtin::BImemmove) 4764 OperationType = 2; 4765 else if (BId == Builtin::BImemcmp) 4766 OperationType = 3; 4767 } 4768 4769 DiagRuntimeBehavior( 4770 Dest->getExprLoc(), Dest, 4771 PDiag(diag::warn_dyn_class_memaccess) 4772 << (BId == Builtin::BImemcmp ? ArgIdx + 2 : ArgIdx) 4773 << FnName << IsContained << ContainedRD << OperationType 4774 << Call->getCallee()->getSourceRange()); 4775 } else if (PointeeTy.hasNonTrivialObjCLifetime() && 4776 BId != Builtin::BImemset) 4777 DiagRuntimeBehavior( 4778 Dest->getExprLoc(), Dest, 4779 PDiag(diag::warn_arc_object_memaccess) 4780 << ArgIdx << FnName << PointeeTy 4781 << Call->getCallee()->getSourceRange()); 4782 else 4783 continue; 4784 4785 DiagRuntimeBehavior( 4786 Dest->getExprLoc(), Dest, 4787 PDiag(diag::note_bad_memaccess_silence) 4788 << FixItHint::CreateInsertion(ArgRange.getBegin(), "(void*)")); 4789 break; 4790 } 4791 } 4792 } 4793 4794 // A little helper routine: ignore addition and subtraction of integer literals. 4795 // This intentionally does not ignore all integer constant expressions because 4796 // we don't want to remove sizeof(). 4797 static const Expr *ignoreLiteralAdditions(const Expr *Ex, ASTContext &Ctx) { 4798 Ex = Ex->IgnoreParenCasts(); 4799 4800 for (;;) { 4801 const BinaryOperator * BO = dyn_cast<BinaryOperator>(Ex); 4802 if (!BO || !BO->isAdditiveOp()) 4803 break; 4804 4805 const Expr *RHS = BO->getRHS()->IgnoreParenCasts(); 4806 const Expr *LHS = BO->getLHS()->IgnoreParenCasts(); 4807 4808 if (isa<IntegerLiteral>(RHS)) 4809 Ex = LHS; 4810 else if (isa<IntegerLiteral>(LHS)) 4811 Ex = RHS; 4812 else 4813 break; 4814 } 4815 4816 return Ex; 4817 } 4818 4819 static bool isConstantSizeArrayWithMoreThanOneElement(QualType Ty, 4820 ASTContext &Context) { 4821 // Only handle constant-sized or VLAs, but not flexible members. 4822 if (const ConstantArrayType *CAT = Context.getAsConstantArrayType(Ty)) { 4823 // Only issue the FIXIT for arrays of size > 1. 4824 if (CAT->getSize().getSExtValue() <= 1) 4825 return false; 4826 } else if (!Ty->isVariableArrayType()) { 4827 return false; 4828 } 4829 return true; 4830 } 4831 4832 // Warn if the user has made the 'size' argument to strlcpy or strlcat 4833 // be the size of the source, instead of the destination. 4834 void Sema::CheckStrlcpycatArguments(const CallExpr *Call, 4835 IdentifierInfo *FnName) { 4836 4837 // Don't crash if the user has the wrong number of arguments 4838 unsigned NumArgs = Call->getNumArgs(); 4839 if ((NumArgs != 3) && (NumArgs != 4)) 4840 return; 4841 4842 const Expr *SrcArg = ignoreLiteralAdditions(Call->getArg(1), Context); 4843 const Expr *SizeArg = ignoreLiteralAdditions(Call->getArg(2), Context); 4844 const Expr *CompareWithSrc = nullptr; 4845 4846 if (CheckMemorySizeofForComparison(*this, SizeArg, FnName, 4847 Call->getLocStart(), Call->getRParenLoc())) 4848 return; 4849 4850 // Look for 'strlcpy(dst, x, sizeof(x))' 4851 if (const Expr *Ex = getSizeOfExprArg(SizeArg)) 4852 CompareWithSrc = Ex; 4853 else { 4854 // Look for 'strlcpy(dst, x, strlen(x))' 4855 if (const CallExpr *SizeCall = dyn_cast<CallExpr>(SizeArg)) { 4856 if (SizeCall->getBuiltinCallee() == Builtin::BIstrlen && 4857 SizeCall->getNumArgs() == 1) 4858 CompareWithSrc = ignoreLiteralAdditions(SizeCall->getArg(0), Context); 4859 } 4860 } 4861 4862 if (!CompareWithSrc) 4863 return; 4864 4865 // Determine if the argument to sizeof/strlen is equal to the source 4866 // argument. In principle there's all kinds of things you could do 4867 // here, for instance creating an == expression and evaluating it with 4868 // EvaluateAsBooleanCondition, but this uses a more direct technique: 4869 const DeclRefExpr *SrcArgDRE = dyn_cast<DeclRefExpr>(SrcArg); 4870 if (!SrcArgDRE) 4871 return; 4872 4873 const DeclRefExpr *CompareWithSrcDRE = dyn_cast<DeclRefExpr>(CompareWithSrc); 4874 if (!CompareWithSrcDRE || 4875 SrcArgDRE->getDecl() != CompareWithSrcDRE->getDecl()) 4876 return; 4877 4878 const Expr *OriginalSizeArg = Call->getArg(2); 4879 Diag(CompareWithSrcDRE->getLocStart(), diag::warn_strlcpycat_wrong_size) 4880 << OriginalSizeArg->getSourceRange() << FnName; 4881 4882 // Output a FIXIT hint if the destination is an array (rather than a 4883 // pointer to an array). This could be enhanced to handle some 4884 // pointers if we know the actual size, like if DstArg is 'array+2' 4885 // we could say 'sizeof(array)-2'. 4886 const Expr *DstArg = Call->getArg(0)->IgnoreParenImpCasts(); 4887 if (!isConstantSizeArrayWithMoreThanOneElement(DstArg->getType(), Context)) 4888 return; 4889 4890 SmallString<128> sizeString; 4891 llvm::raw_svector_ostream OS(sizeString); 4892 OS << "sizeof("; 4893 DstArg->printPretty(OS, nullptr, getPrintingPolicy()); 4894 OS << ")"; 4895 4896 Diag(OriginalSizeArg->getLocStart(), diag::note_strlcpycat_wrong_size) 4897 << FixItHint::CreateReplacement(OriginalSizeArg->getSourceRange(), 4898 OS.str()); 4899 } 4900 4901 /// Check if two expressions refer to the same declaration. 4902 static bool referToTheSameDecl(const Expr *E1, const Expr *E2) { 4903 if (const DeclRefExpr *D1 = dyn_cast_or_null<DeclRefExpr>(E1)) 4904 if (const DeclRefExpr *D2 = dyn_cast_or_null<DeclRefExpr>(E2)) 4905 return D1->getDecl() == D2->getDecl(); 4906 return false; 4907 } 4908 4909 static const Expr *getStrlenExprArg(const Expr *E) { 4910 if (const CallExpr *CE = dyn_cast<CallExpr>(E)) { 4911 const FunctionDecl *FD = CE->getDirectCallee(); 4912 if (!FD || FD->getMemoryFunctionKind() != Builtin::BIstrlen) 4913 return nullptr; 4914 return CE->getArg(0)->IgnoreParenCasts(); 4915 } 4916 return nullptr; 4917 } 4918 4919 // Warn on anti-patterns as the 'size' argument to strncat. 4920 // The correct size argument should look like following: 4921 // strncat(dst, src, sizeof(dst) - strlen(dest) - 1); 4922 void Sema::CheckStrncatArguments(const CallExpr *CE, 4923 IdentifierInfo *FnName) { 4924 // Don't crash if the user has the wrong number of arguments. 4925 if (CE->getNumArgs() < 3) 4926 return; 4927 const Expr *DstArg = CE->getArg(0)->IgnoreParenCasts(); 4928 const Expr *SrcArg = CE->getArg(1)->IgnoreParenCasts(); 4929 const Expr *LenArg = CE->getArg(2)->IgnoreParenCasts(); 4930 4931 if (CheckMemorySizeofForComparison(*this, LenArg, FnName, CE->getLocStart(), 4932 CE->getRParenLoc())) 4933 return; 4934 4935 // Identify common expressions, which are wrongly used as the size argument 4936 // to strncat and may lead to buffer overflows. 4937 unsigned PatternType = 0; 4938 if (const Expr *SizeOfArg = getSizeOfExprArg(LenArg)) { 4939 // - sizeof(dst) 4940 if (referToTheSameDecl(SizeOfArg, DstArg)) 4941 PatternType = 1; 4942 // - sizeof(src) 4943 else if (referToTheSameDecl(SizeOfArg, SrcArg)) 4944 PatternType = 2; 4945 } else if (const BinaryOperator *BE = dyn_cast<BinaryOperator>(LenArg)) { 4946 if (BE->getOpcode() == BO_Sub) { 4947 const Expr *L = BE->getLHS()->IgnoreParenCasts(); 4948 const Expr *R = BE->getRHS()->IgnoreParenCasts(); 4949 // - sizeof(dst) - strlen(dst) 4950 if (referToTheSameDecl(DstArg, getSizeOfExprArg(L)) && 4951 referToTheSameDecl(DstArg, getStrlenExprArg(R))) 4952 PatternType = 1; 4953 // - sizeof(src) - (anything) 4954 else if (referToTheSameDecl(SrcArg, getSizeOfExprArg(L))) 4955 PatternType = 2; 4956 } 4957 } 4958 4959 if (PatternType == 0) 4960 return; 4961 4962 // Generate the diagnostic. 4963 SourceLocation SL = LenArg->getLocStart(); 4964 SourceRange SR = LenArg->getSourceRange(); 4965 SourceManager &SM = getSourceManager(); 4966 4967 // If the function is defined as a builtin macro, do not show macro expansion. 4968 if (SM.isMacroArgExpansion(SL)) { 4969 SL = SM.getSpellingLoc(SL); 4970 SR = SourceRange(SM.getSpellingLoc(SR.getBegin()), 4971 SM.getSpellingLoc(SR.getEnd())); 4972 } 4973 4974 // Check if the destination is an array (rather than a pointer to an array). 4975 QualType DstTy = DstArg->getType(); 4976 bool isKnownSizeArray = isConstantSizeArrayWithMoreThanOneElement(DstTy, 4977 Context); 4978 if (!isKnownSizeArray) { 4979 if (PatternType == 1) 4980 Diag(SL, diag::warn_strncat_wrong_size) << SR; 4981 else 4982 Diag(SL, diag::warn_strncat_src_size) << SR; 4983 return; 4984 } 4985 4986 if (PatternType == 1) 4987 Diag(SL, diag::warn_strncat_large_size) << SR; 4988 else 4989 Diag(SL, diag::warn_strncat_src_size) << SR; 4990 4991 SmallString<128> sizeString; 4992 llvm::raw_svector_ostream OS(sizeString); 4993 OS << "sizeof("; 4994 DstArg->printPretty(OS, nullptr, getPrintingPolicy()); 4995 OS << ") - "; 4996 OS << "strlen("; 4997 DstArg->printPretty(OS, nullptr, getPrintingPolicy()); 4998 OS << ") - 1"; 4999 5000 Diag(SL, diag::note_strncat_wrong_size) 5001 << FixItHint::CreateReplacement(SR, OS.str()); 5002 } 5003 5004 //===--- CHECK: Return Address of Stack Variable --------------------------===// 5005 5006 static Expr *EvalVal(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars, 5007 Decl *ParentDecl); 5008 static Expr *EvalAddr(Expr* E, SmallVectorImpl<DeclRefExpr *> &refVars, 5009 Decl *ParentDecl); 5010 5011 /// CheckReturnStackAddr - Check if a return statement returns the address 5012 /// of a stack variable. 5013 static void 5014 CheckReturnStackAddr(Sema &S, Expr *RetValExp, QualType lhsType, 5015 SourceLocation ReturnLoc) { 5016 5017 Expr *stackE = nullptr; 5018 SmallVector<DeclRefExpr *, 8> refVars; 5019 5020 // Perform checking for returned stack addresses, local blocks, 5021 // label addresses or references to temporaries. 5022 if (lhsType->isPointerType() || 5023 (!S.getLangOpts().ObjCAutoRefCount && lhsType->isBlockPointerType())) { 5024 stackE = EvalAddr(RetValExp, refVars, /*ParentDecl=*/nullptr); 5025 } else if (lhsType->isReferenceType()) { 5026 stackE = EvalVal(RetValExp, refVars, /*ParentDecl=*/nullptr); 5027 } 5028 5029 if (!stackE) 5030 return; // Nothing suspicious was found. 5031 5032 SourceLocation diagLoc; 5033 SourceRange diagRange; 5034 if (refVars.empty()) { 5035 diagLoc = stackE->getLocStart(); 5036 diagRange = stackE->getSourceRange(); 5037 } else { 5038 // We followed through a reference variable. 'stackE' contains the 5039 // problematic expression but we will warn at the return statement pointing 5040 // at the reference variable. We will later display the "trail" of 5041 // reference variables using notes. 5042 diagLoc = refVars[0]->getLocStart(); 5043 diagRange = refVars[0]->getSourceRange(); 5044 } 5045 5046 if (DeclRefExpr *DR = dyn_cast<DeclRefExpr>(stackE)) { //address of local var. 5047 S.Diag(diagLoc, lhsType->isReferenceType() ? diag::warn_ret_stack_ref 5048 : diag::warn_ret_stack_addr) 5049 << DR->getDecl()->getDeclName() << diagRange; 5050 } else if (isa<BlockExpr>(stackE)) { // local block. 5051 S.Diag(diagLoc, diag::err_ret_local_block) << diagRange; 5052 } else if (isa<AddrLabelExpr>(stackE)) { // address of label. 5053 S.Diag(diagLoc, diag::warn_ret_addr_label) << diagRange; 5054 } else { // local temporary. 5055 S.Diag(diagLoc, lhsType->isReferenceType() ? diag::warn_ret_local_temp_ref 5056 : diag::warn_ret_local_temp_addr) 5057 << diagRange; 5058 } 5059 5060 // Display the "trail" of reference variables that we followed until we 5061 // found the problematic expression using notes. 5062 for (unsigned i = 0, e = refVars.size(); i != e; ++i) { 5063 VarDecl *VD = cast<VarDecl>(refVars[i]->getDecl()); 5064 // If this var binds to another reference var, show the range of the next 5065 // var, otherwise the var binds to the problematic expression, in which case 5066 // show the range of the expression. 5067 SourceRange range = (i < e-1) ? refVars[i+1]->getSourceRange() 5068 : stackE->getSourceRange(); 5069 S.Diag(VD->getLocation(), diag::note_ref_var_local_bind) 5070 << VD->getDeclName() << range; 5071 } 5072 } 5073 5074 /// EvalAddr - EvalAddr and EvalVal are mutually recursive functions that 5075 /// check if the expression in a return statement evaluates to an address 5076 /// to a location on the stack, a local block, an address of a label, or a 5077 /// reference to local temporary. The recursion is used to traverse the 5078 /// AST of the return expression, with recursion backtracking when we 5079 /// encounter a subexpression that (1) clearly does not lead to one of the 5080 /// above problematic expressions (2) is something we cannot determine leads to 5081 /// a problematic expression based on such local checking. 5082 /// 5083 /// Both EvalAddr and EvalVal follow through reference variables to evaluate 5084 /// the expression that they point to. Such variables are added to the 5085 /// 'refVars' vector so that we know what the reference variable "trail" was. 5086 /// 5087 /// EvalAddr processes expressions that are pointers that are used as 5088 /// references (and not L-values). EvalVal handles all other values. 5089 /// At the base case of the recursion is a check for the above problematic 5090 /// expressions. 5091 /// 5092 /// This implementation handles: 5093 /// 5094 /// * pointer-to-pointer casts 5095 /// * implicit conversions from array references to pointers 5096 /// * taking the address of fields 5097 /// * arbitrary interplay between "&" and "*" operators 5098 /// * pointer arithmetic from an address of a stack variable 5099 /// * taking the address of an array element where the array is on the stack 5100 static Expr *EvalAddr(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars, 5101 Decl *ParentDecl) { 5102 if (E->isTypeDependent()) 5103 return nullptr; 5104 5105 // We should only be called for evaluating pointer expressions. 5106 assert((E->getType()->isAnyPointerType() || 5107 E->getType()->isBlockPointerType() || 5108 E->getType()->isObjCQualifiedIdType()) && 5109 "EvalAddr only works on pointers"); 5110 5111 E = E->IgnoreParens(); 5112 5113 // Our "symbolic interpreter" is just a dispatch off the currently 5114 // viewed AST node. We then recursively traverse the AST by calling 5115 // EvalAddr and EvalVal appropriately. 5116 switch (E->getStmtClass()) { 5117 case Stmt::DeclRefExprClass: { 5118 DeclRefExpr *DR = cast<DeclRefExpr>(E); 5119 5120 // If we leave the immediate function, the lifetime isn't about to end. 5121 if (DR->refersToEnclosingVariableOrCapture()) 5122 return nullptr; 5123 5124 if (VarDecl *V = dyn_cast<VarDecl>(DR->getDecl())) 5125 // If this is a reference variable, follow through to the expression that 5126 // it points to. 5127 if (V->hasLocalStorage() && 5128 V->getType()->isReferenceType() && V->hasInit()) { 5129 // Add the reference variable to the "trail". 5130 refVars.push_back(DR); 5131 return EvalAddr(V->getInit(), refVars, ParentDecl); 5132 } 5133 5134 return nullptr; 5135 } 5136 5137 case Stmt::UnaryOperatorClass: { 5138 // The only unary operator that make sense to handle here 5139 // is AddrOf. All others don't make sense as pointers. 5140 UnaryOperator *U = cast<UnaryOperator>(E); 5141 5142 if (U->getOpcode() == UO_AddrOf) 5143 return EvalVal(U->getSubExpr(), refVars, ParentDecl); 5144 else 5145 return nullptr; 5146 } 5147 5148 case Stmt::BinaryOperatorClass: { 5149 // Handle pointer arithmetic. All other binary operators are not valid 5150 // in this context. 5151 BinaryOperator *B = cast<BinaryOperator>(E); 5152 BinaryOperatorKind op = B->getOpcode(); 5153 5154 if (op != BO_Add && op != BO_Sub) 5155 return nullptr; 5156 5157 Expr *Base = B->getLHS(); 5158 5159 // Determine which argument is the real pointer base. It could be 5160 // the RHS argument instead of the LHS. 5161 if (!Base->getType()->isPointerType()) Base = B->getRHS(); 5162 5163 assert (Base->getType()->isPointerType()); 5164 return EvalAddr(Base, refVars, ParentDecl); 5165 } 5166 5167 // For conditional operators we need to see if either the LHS or RHS are 5168 // valid DeclRefExpr*s. If one of them is valid, we return it. 5169 case Stmt::ConditionalOperatorClass: { 5170 ConditionalOperator *C = cast<ConditionalOperator>(E); 5171 5172 // Handle the GNU extension for missing LHS. 5173 // FIXME: That isn't a ConditionalOperator, so doesn't get here. 5174 if (Expr *LHSExpr = C->getLHS()) { 5175 // In C++, we can have a throw-expression, which has 'void' type. 5176 if (!LHSExpr->getType()->isVoidType()) 5177 if (Expr *LHS = EvalAddr(LHSExpr, refVars, ParentDecl)) 5178 return LHS; 5179 } 5180 5181 // In C++, we can have a throw-expression, which has 'void' type. 5182 if (C->getRHS()->getType()->isVoidType()) 5183 return nullptr; 5184 5185 return EvalAddr(C->getRHS(), refVars, ParentDecl); 5186 } 5187 5188 case Stmt::BlockExprClass: 5189 if (cast<BlockExpr>(E)->getBlockDecl()->hasCaptures()) 5190 return E; // local block. 5191 return nullptr; 5192 5193 case Stmt::AddrLabelExprClass: 5194 return E; // address of label. 5195 5196 case Stmt::ExprWithCleanupsClass: 5197 return EvalAddr(cast<ExprWithCleanups>(E)->getSubExpr(), refVars, 5198 ParentDecl); 5199 5200 // For casts, we need to handle conversions from arrays to 5201 // pointer values, and pointer-to-pointer conversions. 5202 case Stmt::ImplicitCastExprClass: 5203 case Stmt::CStyleCastExprClass: 5204 case Stmt::CXXFunctionalCastExprClass: 5205 case Stmt::ObjCBridgedCastExprClass: 5206 case Stmt::CXXStaticCastExprClass: 5207 case Stmt::CXXDynamicCastExprClass: 5208 case Stmt::CXXConstCastExprClass: 5209 case Stmt::CXXReinterpretCastExprClass: { 5210 Expr* SubExpr = cast<CastExpr>(E)->getSubExpr(); 5211 switch (cast<CastExpr>(E)->getCastKind()) { 5212 case CK_LValueToRValue: 5213 case CK_NoOp: 5214 case CK_BaseToDerived: 5215 case CK_DerivedToBase: 5216 case CK_UncheckedDerivedToBase: 5217 case CK_Dynamic: 5218 case CK_CPointerToObjCPointerCast: 5219 case CK_BlockPointerToObjCPointerCast: 5220 case CK_AnyPointerToBlockPointerCast: 5221 return EvalAddr(SubExpr, refVars, ParentDecl); 5222 5223 case CK_ArrayToPointerDecay: 5224 return EvalVal(SubExpr, refVars, ParentDecl); 5225 5226 case CK_BitCast: 5227 if (SubExpr->getType()->isAnyPointerType() || 5228 SubExpr->getType()->isBlockPointerType() || 5229 SubExpr->getType()->isObjCQualifiedIdType()) 5230 return EvalAddr(SubExpr, refVars, ParentDecl); 5231 else 5232 return nullptr; 5233 5234 default: 5235 return nullptr; 5236 } 5237 } 5238 5239 case Stmt::MaterializeTemporaryExprClass: 5240 if (Expr *Result = EvalAddr( 5241 cast<MaterializeTemporaryExpr>(E)->GetTemporaryExpr(), 5242 refVars, ParentDecl)) 5243 return Result; 5244 5245 return E; 5246 5247 // Everything else: we simply don't reason about them. 5248 default: 5249 return nullptr; 5250 } 5251 } 5252 5253 5254 /// EvalVal - This function is complements EvalAddr in the mutual recursion. 5255 /// See the comments for EvalAddr for more details. 5256 static Expr *EvalVal(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars, 5257 Decl *ParentDecl) { 5258 do { 5259 // We should only be called for evaluating non-pointer expressions, or 5260 // expressions with a pointer type that are not used as references but instead 5261 // are l-values (e.g., DeclRefExpr with a pointer type). 5262 5263 // Our "symbolic interpreter" is just a dispatch off the currently 5264 // viewed AST node. We then recursively traverse the AST by calling 5265 // EvalAddr and EvalVal appropriately. 5266 5267 E = E->IgnoreParens(); 5268 switch (E->getStmtClass()) { 5269 case Stmt::ImplicitCastExprClass: { 5270 ImplicitCastExpr *IE = cast<ImplicitCastExpr>(E); 5271 if (IE->getValueKind() == VK_LValue) { 5272 E = IE->getSubExpr(); 5273 continue; 5274 } 5275 return nullptr; 5276 } 5277 5278 case Stmt::ExprWithCleanupsClass: 5279 return EvalVal(cast<ExprWithCleanups>(E)->getSubExpr(), refVars,ParentDecl); 5280 5281 case Stmt::DeclRefExprClass: { 5282 // When we hit a DeclRefExpr we are looking at code that refers to a 5283 // variable's name. If it's not a reference variable we check if it has 5284 // local storage within the function, and if so, return the expression. 5285 DeclRefExpr *DR = cast<DeclRefExpr>(E); 5286 5287 // If we leave the immediate function, the lifetime isn't about to end. 5288 if (DR->refersToEnclosingVariableOrCapture()) 5289 return nullptr; 5290 5291 if (VarDecl *V = dyn_cast<VarDecl>(DR->getDecl())) { 5292 // Check if it refers to itself, e.g. "int& i = i;". 5293 if (V == ParentDecl) 5294 return DR; 5295 5296 if (V->hasLocalStorage()) { 5297 if (!V->getType()->isReferenceType()) 5298 return DR; 5299 5300 // Reference variable, follow through to the expression that 5301 // it points to. 5302 if (V->hasInit()) { 5303 // Add the reference variable to the "trail". 5304 refVars.push_back(DR); 5305 return EvalVal(V->getInit(), refVars, V); 5306 } 5307 } 5308 } 5309 5310 return nullptr; 5311 } 5312 5313 case Stmt::UnaryOperatorClass: { 5314 // The only unary operator that make sense to handle here 5315 // is Deref. All others don't resolve to a "name." This includes 5316 // handling all sorts of rvalues passed to a unary operator. 5317 UnaryOperator *U = cast<UnaryOperator>(E); 5318 5319 if (U->getOpcode() == UO_Deref) 5320 return EvalAddr(U->getSubExpr(), refVars, ParentDecl); 5321 5322 return nullptr; 5323 } 5324 5325 case Stmt::ArraySubscriptExprClass: { 5326 // Array subscripts are potential references to data on the stack. We 5327 // retrieve the DeclRefExpr* for the array variable if it indeed 5328 // has local storage. 5329 return EvalAddr(cast<ArraySubscriptExpr>(E)->getBase(), refVars,ParentDecl); 5330 } 5331 5332 case Stmt::ConditionalOperatorClass: { 5333 // For conditional operators we need to see if either the LHS or RHS are 5334 // non-NULL Expr's. If one is non-NULL, we return it. 5335 ConditionalOperator *C = cast<ConditionalOperator>(E); 5336 5337 // Handle the GNU extension for missing LHS. 5338 if (Expr *LHSExpr = C->getLHS()) { 5339 // In C++, we can have a throw-expression, which has 'void' type. 5340 if (!LHSExpr->getType()->isVoidType()) 5341 if (Expr *LHS = EvalVal(LHSExpr, refVars, ParentDecl)) 5342 return LHS; 5343 } 5344 5345 // In C++, we can have a throw-expression, which has 'void' type. 5346 if (C->getRHS()->getType()->isVoidType()) 5347 return nullptr; 5348 5349 return EvalVal(C->getRHS(), refVars, ParentDecl); 5350 } 5351 5352 // Accesses to members are potential references to data on the stack. 5353 case Stmt::MemberExprClass: { 5354 MemberExpr *M = cast<MemberExpr>(E); 5355 5356 // Check for indirect access. We only want direct field accesses. 5357 if (M->isArrow()) 5358 return nullptr; 5359 5360 // Check whether the member type is itself a reference, in which case 5361 // we're not going to refer to the member, but to what the member refers to. 5362 if (M->getMemberDecl()->getType()->isReferenceType()) 5363 return nullptr; 5364 5365 return EvalVal(M->getBase(), refVars, ParentDecl); 5366 } 5367 5368 case Stmt::MaterializeTemporaryExprClass: 5369 if (Expr *Result = EvalVal( 5370 cast<MaterializeTemporaryExpr>(E)->GetTemporaryExpr(), 5371 refVars, ParentDecl)) 5372 return Result; 5373 5374 return E; 5375 5376 default: 5377 // Check that we don't return or take the address of a reference to a 5378 // temporary. This is only useful in C++. 5379 if (!E->isTypeDependent() && E->isRValue()) 5380 return E; 5381 5382 // Everything else: we simply don't reason about them. 5383 return nullptr; 5384 } 5385 } while (true); 5386 } 5387 5388 void 5389 Sema::CheckReturnValExpr(Expr *RetValExp, QualType lhsType, 5390 SourceLocation ReturnLoc, 5391 bool isObjCMethod, 5392 const AttrVec *Attrs, 5393 const FunctionDecl *FD) { 5394 CheckReturnStackAddr(*this, RetValExp, lhsType, ReturnLoc); 5395 5396 // Check if the return value is null but should not be. 5397 if (Attrs && hasSpecificAttr<ReturnsNonNullAttr>(*Attrs) && 5398 CheckNonNullExpr(*this, RetValExp)) 5399 Diag(ReturnLoc, diag::warn_null_ret) 5400 << (isObjCMethod ? 1 : 0) << RetValExp->getSourceRange(); 5401 5402 // C++11 [basic.stc.dynamic.allocation]p4: 5403 // If an allocation function declared with a non-throwing 5404 // exception-specification fails to allocate storage, it shall return 5405 // a null pointer. Any other allocation function that fails to allocate 5406 // storage shall indicate failure only by throwing an exception [...] 5407 if (FD) { 5408 OverloadedOperatorKind Op = FD->getOverloadedOperator(); 5409 if (Op == OO_New || Op == OO_Array_New) { 5410 const FunctionProtoType *Proto 5411 = FD->getType()->castAs<FunctionProtoType>(); 5412 if (!Proto->isNothrow(Context, /*ResultIfDependent*/true) && 5413 CheckNonNullExpr(*this, RetValExp)) 5414 Diag(ReturnLoc, diag::warn_operator_new_returns_null) 5415 << FD << getLangOpts().CPlusPlus11; 5416 } 5417 } 5418 } 5419 5420 //===--- CHECK: Floating-Point comparisons (-Wfloat-equal) ---------------===// 5421 5422 /// Check for comparisons of floating point operands using != and ==. 5423 /// Issue a warning if these are no self-comparisons, as they are not likely 5424 /// to do what the programmer intended. 5425 void Sema::CheckFloatComparison(SourceLocation Loc, Expr* LHS, Expr *RHS) { 5426 Expr* LeftExprSansParen = LHS->IgnoreParenImpCasts(); 5427 Expr* RightExprSansParen = RHS->IgnoreParenImpCasts(); 5428 5429 // Special case: check for x == x (which is OK). 5430 // Do not emit warnings for such cases. 5431 if (DeclRefExpr* DRL = dyn_cast<DeclRefExpr>(LeftExprSansParen)) 5432 if (DeclRefExpr* DRR = dyn_cast<DeclRefExpr>(RightExprSansParen)) 5433 if (DRL->getDecl() == DRR->getDecl()) 5434 return; 5435 5436 5437 // Special case: check for comparisons against literals that can be exactly 5438 // represented by APFloat. In such cases, do not emit a warning. This 5439 // is a heuristic: often comparison against such literals are used to 5440 // detect if a value in a variable has not changed. This clearly can 5441 // lead to false negatives. 5442 if (FloatingLiteral* FLL = dyn_cast<FloatingLiteral>(LeftExprSansParen)) { 5443 if (FLL->isExact()) 5444 return; 5445 } else 5446 if (FloatingLiteral* FLR = dyn_cast<FloatingLiteral>(RightExprSansParen)) 5447 if (FLR->isExact()) 5448 return; 5449 5450 // Check for comparisons with builtin types. 5451 if (CallExpr* CL = dyn_cast<CallExpr>(LeftExprSansParen)) 5452 if (CL->getBuiltinCallee()) 5453 return; 5454 5455 if (CallExpr* CR = dyn_cast<CallExpr>(RightExprSansParen)) 5456 if (CR->getBuiltinCallee()) 5457 return; 5458 5459 // Emit the diagnostic. 5460 Diag(Loc, diag::warn_floatingpoint_eq) 5461 << LHS->getSourceRange() << RHS->getSourceRange(); 5462 } 5463 5464 //===--- CHECK: Integer mixed-sign comparisons (-Wsign-compare) --------===// 5465 //===--- CHECK: Lossy implicit conversions (-Wconversion) --------------===// 5466 5467 namespace { 5468 5469 /// Structure recording the 'active' range of an integer-valued 5470 /// expression. 5471 struct IntRange { 5472 /// The number of bits active in the int. 5473 unsigned Width; 5474 5475 /// True if the int is known not to have negative values. 5476 bool NonNegative; 5477 5478 IntRange(unsigned Width, bool NonNegative) 5479 : Width(Width), NonNegative(NonNegative) 5480 {} 5481 5482 /// Returns the range of the bool type. 5483 static IntRange forBoolType() { 5484 return IntRange(1, true); 5485 } 5486 5487 /// Returns the range of an opaque value of the given integral type. 5488 static IntRange forValueOfType(ASTContext &C, QualType T) { 5489 return forValueOfCanonicalType(C, 5490 T->getCanonicalTypeInternal().getTypePtr()); 5491 } 5492 5493 /// Returns the range of an opaque value of a canonical integral type. 5494 static IntRange forValueOfCanonicalType(ASTContext &C, const Type *T) { 5495 assert(T->isCanonicalUnqualified()); 5496 5497 if (const VectorType *VT = dyn_cast<VectorType>(T)) 5498 T = VT->getElementType().getTypePtr(); 5499 if (const ComplexType *CT = dyn_cast<ComplexType>(T)) 5500 T = CT->getElementType().getTypePtr(); 5501 if (const AtomicType *AT = dyn_cast<AtomicType>(T)) 5502 T = AT->getValueType().getTypePtr(); 5503 5504 // For enum types, use the known bit width of the enumerators. 5505 if (const EnumType *ET = dyn_cast<EnumType>(T)) { 5506 EnumDecl *Enum = ET->getDecl(); 5507 if (!Enum->isCompleteDefinition()) 5508 return IntRange(C.getIntWidth(QualType(T, 0)), false); 5509 5510 unsigned NumPositive = Enum->getNumPositiveBits(); 5511 unsigned NumNegative = Enum->getNumNegativeBits(); 5512 5513 if (NumNegative == 0) 5514 return IntRange(NumPositive, true/*NonNegative*/); 5515 else 5516 return IntRange(std::max(NumPositive + 1, NumNegative), 5517 false/*NonNegative*/); 5518 } 5519 5520 const BuiltinType *BT = cast<BuiltinType>(T); 5521 assert(BT->isInteger()); 5522 5523 return IntRange(C.getIntWidth(QualType(T, 0)), BT->isUnsignedInteger()); 5524 } 5525 5526 /// Returns the "target" range of a canonical integral type, i.e. 5527 /// the range of values expressible in the type. 5528 /// 5529 /// This matches forValueOfCanonicalType except that enums have the 5530 /// full range of their type, not the range of their enumerators. 5531 static IntRange forTargetOfCanonicalType(ASTContext &C, const Type *T) { 5532 assert(T->isCanonicalUnqualified()); 5533 5534 if (const VectorType *VT = dyn_cast<VectorType>(T)) 5535 T = VT->getElementType().getTypePtr(); 5536 if (const ComplexType *CT = dyn_cast<ComplexType>(T)) 5537 T = CT->getElementType().getTypePtr(); 5538 if (const AtomicType *AT = dyn_cast<AtomicType>(T)) 5539 T = AT->getValueType().getTypePtr(); 5540 if (const EnumType *ET = dyn_cast<EnumType>(T)) 5541 T = C.getCanonicalType(ET->getDecl()->getIntegerType()).getTypePtr(); 5542 5543 const BuiltinType *BT = cast<BuiltinType>(T); 5544 assert(BT->isInteger()); 5545 5546 return IntRange(C.getIntWidth(QualType(T, 0)), BT->isUnsignedInteger()); 5547 } 5548 5549 /// Returns the supremum of two ranges: i.e. their conservative merge. 5550 static IntRange join(IntRange L, IntRange R) { 5551 return IntRange(std::max(L.Width, R.Width), 5552 L.NonNegative && R.NonNegative); 5553 } 5554 5555 /// Returns the infinum of two ranges: i.e. their aggressive merge. 5556 static IntRange meet(IntRange L, IntRange R) { 5557 return IntRange(std::min(L.Width, R.Width), 5558 L.NonNegative || R.NonNegative); 5559 } 5560 }; 5561 5562 static IntRange GetValueRange(ASTContext &C, llvm::APSInt &value, 5563 unsigned MaxWidth) { 5564 if (value.isSigned() && value.isNegative()) 5565 return IntRange(value.getMinSignedBits(), false); 5566 5567 if (value.getBitWidth() > MaxWidth) 5568 value = value.trunc(MaxWidth); 5569 5570 // isNonNegative() just checks the sign bit without considering 5571 // signedness. 5572 return IntRange(value.getActiveBits(), true); 5573 } 5574 5575 static IntRange GetValueRange(ASTContext &C, APValue &result, QualType Ty, 5576 unsigned MaxWidth) { 5577 if (result.isInt()) 5578 return GetValueRange(C, result.getInt(), MaxWidth); 5579 5580 if (result.isVector()) { 5581 IntRange R = GetValueRange(C, result.getVectorElt(0), Ty, MaxWidth); 5582 for (unsigned i = 1, e = result.getVectorLength(); i != e; ++i) { 5583 IntRange El = GetValueRange(C, result.getVectorElt(i), Ty, MaxWidth); 5584 R = IntRange::join(R, El); 5585 } 5586 return R; 5587 } 5588 5589 if (result.isComplexInt()) { 5590 IntRange R = GetValueRange(C, result.getComplexIntReal(), MaxWidth); 5591 IntRange I = GetValueRange(C, result.getComplexIntImag(), MaxWidth); 5592 return IntRange::join(R, I); 5593 } 5594 5595 // This can happen with lossless casts to intptr_t of "based" lvalues. 5596 // Assume it might use arbitrary bits. 5597 // FIXME: The only reason we need to pass the type in here is to get 5598 // the sign right on this one case. It would be nice if APValue 5599 // preserved this. 5600 assert(result.isLValue() || result.isAddrLabelDiff()); 5601 return IntRange(MaxWidth, Ty->isUnsignedIntegerOrEnumerationType()); 5602 } 5603 5604 static QualType GetExprType(Expr *E) { 5605 QualType Ty = E->getType(); 5606 if (const AtomicType *AtomicRHS = Ty->getAs<AtomicType>()) 5607 Ty = AtomicRHS->getValueType(); 5608 return Ty; 5609 } 5610 5611 /// Pseudo-evaluate the given integer expression, estimating the 5612 /// range of values it might take. 5613 /// 5614 /// \param MaxWidth - the width to which the value will be truncated 5615 static IntRange GetExprRange(ASTContext &C, Expr *E, unsigned MaxWidth) { 5616 E = E->IgnoreParens(); 5617 5618 // Try a full evaluation first. 5619 Expr::EvalResult result; 5620 if (E->EvaluateAsRValue(result, C)) 5621 return GetValueRange(C, result.Val, GetExprType(E), MaxWidth); 5622 5623 // I think we only want to look through implicit casts here; if the 5624 // user has an explicit widening cast, we should treat the value as 5625 // being of the new, wider type. 5626 if (ImplicitCastExpr *CE = dyn_cast<ImplicitCastExpr>(E)) { 5627 if (CE->getCastKind() == CK_NoOp || CE->getCastKind() == CK_LValueToRValue) 5628 return GetExprRange(C, CE->getSubExpr(), MaxWidth); 5629 5630 IntRange OutputTypeRange = IntRange::forValueOfType(C, GetExprType(CE)); 5631 5632 bool isIntegerCast = (CE->getCastKind() == CK_IntegralCast); 5633 5634 // Assume that non-integer casts can span the full range of the type. 5635 if (!isIntegerCast) 5636 return OutputTypeRange; 5637 5638 IntRange SubRange 5639 = GetExprRange(C, CE->getSubExpr(), 5640 std::min(MaxWidth, OutputTypeRange.Width)); 5641 5642 // Bail out if the subexpr's range is as wide as the cast type. 5643 if (SubRange.Width >= OutputTypeRange.Width) 5644 return OutputTypeRange; 5645 5646 // Otherwise, we take the smaller width, and we're non-negative if 5647 // either the output type or the subexpr is. 5648 return IntRange(SubRange.Width, 5649 SubRange.NonNegative || OutputTypeRange.NonNegative); 5650 } 5651 5652 if (ConditionalOperator *CO = dyn_cast<ConditionalOperator>(E)) { 5653 // If we can fold the condition, just take that operand. 5654 bool CondResult; 5655 if (CO->getCond()->EvaluateAsBooleanCondition(CondResult, C)) 5656 return GetExprRange(C, CondResult ? CO->getTrueExpr() 5657 : CO->getFalseExpr(), 5658 MaxWidth); 5659 5660 // Otherwise, conservatively merge. 5661 IntRange L = GetExprRange(C, CO->getTrueExpr(), MaxWidth); 5662 IntRange R = GetExprRange(C, CO->getFalseExpr(), MaxWidth); 5663 return IntRange::join(L, R); 5664 } 5665 5666 if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) { 5667 switch (BO->getOpcode()) { 5668 5669 // Boolean-valued operations are single-bit and positive. 5670 case BO_LAnd: 5671 case BO_LOr: 5672 case BO_LT: 5673 case BO_GT: 5674 case BO_LE: 5675 case BO_GE: 5676 case BO_EQ: 5677 case BO_NE: 5678 return IntRange::forBoolType(); 5679 5680 // The type of the assignments is the type of the LHS, so the RHS 5681 // is not necessarily the same type. 5682 case BO_MulAssign: 5683 case BO_DivAssign: 5684 case BO_RemAssign: 5685 case BO_AddAssign: 5686 case BO_SubAssign: 5687 case BO_XorAssign: 5688 case BO_OrAssign: 5689 // TODO: bitfields? 5690 return IntRange::forValueOfType(C, GetExprType(E)); 5691 5692 // Simple assignments just pass through the RHS, which will have 5693 // been coerced to the LHS type. 5694 case BO_Assign: 5695 // TODO: bitfields? 5696 return GetExprRange(C, BO->getRHS(), MaxWidth); 5697 5698 // Operations with opaque sources are black-listed. 5699 case BO_PtrMemD: 5700 case BO_PtrMemI: 5701 return IntRange::forValueOfType(C, GetExprType(E)); 5702 5703 // Bitwise-and uses the *infinum* of the two source ranges. 5704 case BO_And: 5705 case BO_AndAssign: 5706 return IntRange::meet(GetExprRange(C, BO->getLHS(), MaxWidth), 5707 GetExprRange(C, BO->getRHS(), MaxWidth)); 5708 5709 // Left shift gets black-listed based on a judgement call. 5710 case BO_Shl: 5711 // ...except that we want to treat '1 << (blah)' as logically 5712 // positive. It's an important idiom. 5713 if (IntegerLiteral *I 5714 = dyn_cast<IntegerLiteral>(BO->getLHS()->IgnoreParenCasts())) { 5715 if (I->getValue() == 1) { 5716 IntRange R = IntRange::forValueOfType(C, GetExprType(E)); 5717 return IntRange(R.Width, /*NonNegative*/ true); 5718 } 5719 } 5720 // fallthrough 5721 5722 case BO_ShlAssign: 5723 return IntRange::forValueOfType(C, GetExprType(E)); 5724 5725 // Right shift by a constant can narrow its left argument. 5726 case BO_Shr: 5727 case BO_ShrAssign: { 5728 IntRange L = GetExprRange(C, BO->getLHS(), MaxWidth); 5729 5730 // If the shift amount is a positive constant, drop the width by 5731 // that much. 5732 llvm::APSInt shift; 5733 if (BO->getRHS()->isIntegerConstantExpr(shift, C) && 5734 shift.isNonNegative()) { 5735 unsigned zext = shift.getZExtValue(); 5736 if (zext >= L.Width) 5737 L.Width = (L.NonNegative ? 0 : 1); 5738 else 5739 L.Width -= zext; 5740 } 5741 5742 return L; 5743 } 5744 5745 // Comma acts as its right operand. 5746 case BO_Comma: 5747 return GetExprRange(C, BO->getRHS(), MaxWidth); 5748 5749 // Black-list pointer subtractions. 5750 case BO_Sub: 5751 if (BO->getLHS()->getType()->isPointerType()) 5752 return IntRange::forValueOfType(C, GetExprType(E)); 5753 break; 5754 5755 // The width of a division result is mostly determined by the size 5756 // of the LHS. 5757 case BO_Div: { 5758 // Don't 'pre-truncate' the operands. 5759 unsigned opWidth = C.getIntWidth(GetExprType(E)); 5760 IntRange L = GetExprRange(C, BO->getLHS(), opWidth); 5761 5762 // If the divisor is constant, use that. 5763 llvm::APSInt divisor; 5764 if (BO->getRHS()->isIntegerConstantExpr(divisor, C)) { 5765 unsigned log2 = divisor.logBase2(); // floor(log_2(divisor)) 5766 if (log2 >= L.Width) 5767 L.Width = (L.NonNegative ? 0 : 1); 5768 else 5769 L.Width = std::min(L.Width - log2, MaxWidth); 5770 return L; 5771 } 5772 5773 // Otherwise, just use the LHS's width. 5774 IntRange R = GetExprRange(C, BO->getRHS(), opWidth); 5775 return IntRange(L.Width, L.NonNegative && R.NonNegative); 5776 } 5777 5778 // The result of a remainder can't be larger than the result of 5779 // either side. 5780 case BO_Rem: { 5781 // Don't 'pre-truncate' the operands. 5782 unsigned opWidth = C.getIntWidth(GetExprType(E)); 5783 IntRange L = GetExprRange(C, BO->getLHS(), opWidth); 5784 IntRange R = GetExprRange(C, BO->getRHS(), opWidth); 5785 5786 IntRange meet = IntRange::meet(L, R); 5787 meet.Width = std::min(meet.Width, MaxWidth); 5788 return meet; 5789 } 5790 5791 // The default behavior is okay for these. 5792 case BO_Mul: 5793 case BO_Add: 5794 case BO_Xor: 5795 case BO_Or: 5796 break; 5797 } 5798 5799 // The default case is to treat the operation as if it were closed 5800 // on the narrowest type that encompasses both operands. 5801 IntRange L = GetExprRange(C, BO->getLHS(), MaxWidth); 5802 IntRange R = GetExprRange(C, BO->getRHS(), MaxWidth); 5803 return IntRange::join(L, R); 5804 } 5805 5806 if (UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) { 5807 switch (UO->getOpcode()) { 5808 // Boolean-valued operations are white-listed. 5809 case UO_LNot: 5810 return IntRange::forBoolType(); 5811 5812 // Operations with opaque sources are black-listed. 5813 case UO_Deref: 5814 case UO_AddrOf: // should be impossible 5815 return IntRange::forValueOfType(C, GetExprType(E)); 5816 5817 default: 5818 return GetExprRange(C, UO->getSubExpr(), MaxWidth); 5819 } 5820 } 5821 5822 if (OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(E)) 5823 return GetExprRange(C, OVE->getSourceExpr(), MaxWidth); 5824 5825 if (FieldDecl *BitField = E->getSourceBitField()) 5826 return IntRange(BitField->getBitWidthValue(C), 5827 BitField->getType()->isUnsignedIntegerOrEnumerationType()); 5828 5829 return IntRange::forValueOfType(C, GetExprType(E)); 5830 } 5831 5832 static IntRange GetExprRange(ASTContext &C, Expr *E) { 5833 return GetExprRange(C, E, C.getIntWidth(GetExprType(E))); 5834 } 5835 5836 /// Checks whether the given value, which currently has the given 5837 /// source semantics, has the same value when coerced through the 5838 /// target semantics. 5839 static bool IsSameFloatAfterCast(const llvm::APFloat &value, 5840 const llvm::fltSemantics &Src, 5841 const llvm::fltSemantics &Tgt) { 5842 llvm::APFloat truncated = value; 5843 5844 bool ignored; 5845 truncated.convert(Src, llvm::APFloat::rmNearestTiesToEven, &ignored); 5846 truncated.convert(Tgt, llvm::APFloat::rmNearestTiesToEven, &ignored); 5847 5848 return truncated.bitwiseIsEqual(value); 5849 } 5850 5851 /// Checks whether the given value, which currently has the given 5852 /// source semantics, has the same value when coerced through the 5853 /// target semantics. 5854 /// 5855 /// The value might be a vector of floats (or a complex number). 5856 static bool IsSameFloatAfterCast(const APValue &value, 5857 const llvm::fltSemantics &Src, 5858 const llvm::fltSemantics &Tgt) { 5859 if (value.isFloat()) 5860 return IsSameFloatAfterCast(value.getFloat(), Src, Tgt); 5861 5862 if (value.isVector()) { 5863 for (unsigned i = 0, e = value.getVectorLength(); i != e; ++i) 5864 if (!IsSameFloatAfterCast(value.getVectorElt(i), Src, Tgt)) 5865 return false; 5866 return true; 5867 } 5868 5869 assert(value.isComplexFloat()); 5870 return (IsSameFloatAfterCast(value.getComplexFloatReal(), Src, Tgt) && 5871 IsSameFloatAfterCast(value.getComplexFloatImag(), Src, Tgt)); 5872 } 5873 5874 static void AnalyzeImplicitConversions(Sema &S, Expr *E, SourceLocation CC); 5875 5876 static bool IsZero(Sema &S, Expr *E) { 5877 // Suppress cases where we are comparing against an enum constant. 5878 if (const DeclRefExpr *DR = 5879 dyn_cast<DeclRefExpr>(E->IgnoreParenImpCasts())) 5880 if (isa<EnumConstantDecl>(DR->getDecl())) 5881 return false; 5882 5883 // Suppress cases where the '0' value is expanded from a macro. 5884 if (E->getLocStart().isMacroID()) 5885 return false; 5886 5887 llvm::APSInt Value; 5888 return E->isIntegerConstantExpr(Value, S.Context) && Value == 0; 5889 } 5890 5891 static bool HasEnumType(Expr *E) { 5892 // Strip off implicit integral promotions. 5893 while (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) { 5894 if (ICE->getCastKind() != CK_IntegralCast && 5895 ICE->getCastKind() != CK_NoOp) 5896 break; 5897 E = ICE->getSubExpr(); 5898 } 5899 5900 return E->getType()->isEnumeralType(); 5901 } 5902 5903 static void CheckTrivialUnsignedComparison(Sema &S, BinaryOperator *E) { 5904 // Disable warning in template instantiations. 5905 if (!S.ActiveTemplateInstantiations.empty()) 5906 return; 5907 5908 BinaryOperatorKind op = E->getOpcode(); 5909 if (E->isValueDependent()) 5910 return; 5911 5912 if (op == BO_LT && IsZero(S, E->getRHS())) { 5913 S.Diag(E->getOperatorLoc(), diag::warn_lunsigned_always_true_comparison) 5914 << "< 0" << "false" << HasEnumType(E->getLHS()) 5915 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); 5916 } else if (op == BO_GE && IsZero(S, E->getRHS())) { 5917 S.Diag(E->getOperatorLoc(), diag::warn_lunsigned_always_true_comparison) 5918 << ">= 0" << "true" << HasEnumType(E->getLHS()) 5919 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); 5920 } else if (op == BO_GT && IsZero(S, E->getLHS())) { 5921 S.Diag(E->getOperatorLoc(), diag::warn_runsigned_always_true_comparison) 5922 << "0 >" << "false" << HasEnumType(E->getRHS()) 5923 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); 5924 } else if (op == BO_LE && IsZero(S, E->getLHS())) { 5925 S.Diag(E->getOperatorLoc(), diag::warn_runsigned_always_true_comparison) 5926 << "0 <=" << "true" << HasEnumType(E->getRHS()) 5927 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); 5928 } 5929 } 5930 5931 static void DiagnoseOutOfRangeComparison(Sema &S, BinaryOperator *E, 5932 Expr *Constant, Expr *Other, 5933 llvm::APSInt Value, 5934 bool RhsConstant) { 5935 // Disable warning in template instantiations. 5936 if (!S.ActiveTemplateInstantiations.empty()) 5937 return; 5938 5939 // TODO: Investigate using GetExprRange() to get tighter bounds 5940 // on the bit ranges. 5941 QualType OtherT = Other->getType(); 5942 if (const AtomicType *AT = dyn_cast<AtomicType>(OtherT)) 5943 OtherT = AT->getValueType(); 5944 IntRange OtherRange = IntRange::forValueOfType(S.Context, OtherT); 5945 unsigned OtherWidth = OtherRange.Width; 5946 5947 bool OtherIsBooleanType = Other->isKnownToHaveBooleanValue(); 5948 5949 // 0 values are handled later by CheckTrivialUnsignedComparison(). 5950 if ((Value == 0) && (!OtherIsBooleanType)) 5951 return; 5952 5953 BinaryOperatorKind op = E->getOpcode(); 5954 bool IsTrue = true; 5955 5956 // Used for diagnostic printout. 5957 enum { 5958 LiteralConstant = 0, 5959 CXXBoolLiteralTrue, 5960 CXXBoolLiteralFalse 5961 } LiteralOrBoolConstant = LiteralConstant; 5962 5963 if (!OtherIsBooleanType) { 5964 QualType ConstantT = Constant->getType(); 5965 QualType CommonT = E->getLHS()->getType(); 5966 5967 if (S.Context.hasSameUnqualifiedType(OtherT, ConstantT)) 5968 return; 5969 assert((OtherT->isIntegerType() && ConstantT->isIntegerType()) && 5970 "comparison with non-integer type"); 5971 5972 bool ConstantSigned = ConstantT->isSignedIntegerType(); 5973 bool CommonSigned = CommonT->isSignedIntegerType(); 5974 5975 bool EqualityOnly = false; 5976 5977 if (CommonSigned) { 5978 // The common type is signed, therefore no signed to unsigned conversion. 5979 if (!OtherRange.NonNegative) { 5980 // Check that the constant is representable in type OtherT. 5981 if (ConstantSigned) { 5982 if (OtherWidth >= Value.getMinSignedBits()) 5983 return; 5984 } else { // !ConstantSigned 5985 if (OtherWidth >= Value.getActiveBits() + 1) 5986 return; 5987 } 5988 } else { // !OtherSigned 5989 // Check that the constant is representable in type OtherT. 5990 // Negative values are out of range. 5991 if (ConstantSigned) { 5992 if (Value.isNonNegative() && OtherWidth >= Value.getActiveBits()) 5993 return; 5994 } else { // !ConstantSigned 5995 if (OtherWidth >= Value.getActiveBits()) 5996 return; 5997 } 5998 } 5999 } else { // !CommonSigned 6000 if (OtherRange.NonNegative) { 6001 if (OtherWidth >= Value.getActiveBits()) 6002 return; 6003 } else { // OtherSigned 6004 assert(!ConstantSigned && 6005 "Two signed types converted to unsigned types."); 6006 // Check to see if the constant is representable in OtherT. 6007 if (OtherWidth > Value.getActiveBits()) 6008 return; 6009 // Check to see if the constant is equivalent to a negative value 6010 // cast to CommonT. 6011 if (S.Context.getIntWidth(ConstantT) == 6012 S.Context.getIntWidth(CommonT) && 6013 Value.isNegative() && Value.getMinSignedBits() <= OtherWidth) 6014 return; 6015 // The constant value rests between values that OtherT can represent 6016 // after conversion. Relational comparison still works, but equality 6017 // comparisons will be tautological. 6018 EqualityOnly = true; 6019 } 6020 } 6021 6022 bool PositiveConstant = !ConstantSigned || Value.isNonNegative(); 6023 6024 if (op == BO_EQ || op == BO_NE) { 6025 IsTrue = op == BO_NE; 6026 } else if (EqualityOnly) { 6027 return; 6028 } else if (RhsConstant) { 6029 if (op == BO_GT || op == BO_GE) 6030 IsTrue = !PositiveConstant; 6031 else // op == BO_LT || op == BO_LE 6032 IsTrue = PositiveConstant; 6033 } else { 6034 if (op == BO_LT || op == BO_LE) 6035 IsTrue = !PositiveConstant; 6036 else // op == BO_GT || op == BO_GE 6037 IsTrue = PositiveConstant; 6038 } 6039 } else { 6040 // Other isKnownToHaveBooleanValue 6041 enum CompareBoolWithConstantResult { AFals, ATrue, Unkwn }; 6042 enum ConstantValue { LT_Zero, Zero, One, GT_One, SizeOfConstVal }; 6043 enum ConstantSide { Lhs, Rhs, SizeOfConstSides }; 6044 6045 static const struct LinkedConditions { 6046 CompareBoolWithConstantResult BO_LT_OP[SizeOfConstSides][SizeOfConstVal]; 6047 CompareBoolWithConstantResult BO_GT_OP[SizeOfConstSides][SizeOfConstVal]; 6048 CompareBoolWithConstantResult BO_LE_OP[SizeOfConstSides][SizeOfConstVal]; 6049 CompareBoolWithConstantResult BO_GE_OP[SizeOfConstSides][SizeOfConstVal]; 6050 CompareBoolWithConstantResult BO_EQ_OP[SizeOfConstSides][SizeOfConstVal]; 6051 CompareBoolWithConstantResult BO_NE_OP[SizeOfConstSides][SizeOfConstVal]; 6052 6053 } TruthTable = { 6054 // Constant on LHS. | Constant on RHS. | 6055 // LT_Zero| Zero | One |GT_One| LT_Zero| Zero | One |GT_One| 6056 { { ATrue, Unkwn, AFals, AFals }, { AFals, AFals, Unkwn, ATrue } }, 6057 { { AFals, AFals, Unkwn, ATrue }, { ATrue, Unkwn, AFals, AFals } }, 6058 { { ATrue, ATrue, Unkwn, AFals }, { AFals, Unkwn, ATrue, ATrue } }, 6059 { { AFals, Unkwn, ATrue, ATrue }, { ATrue, ATrue, Unkwn, AFals } }, 6060 { { AFals, Unkwn, Unkwn, AFals }, { AFals, Unkwn, Unkwn, AFals } }, 6061 { { ATrue, Unkwn, Unkwn, ATrue }, { ATrue, Unkwn, Unkwn, ATrue } } 6062 }; 6063 6064 bool ConstantIsBoolLiteral = isa<CXXBoolLiteralExpr>(Constant); 6065 6066 enum ConstantValue ConstVal = Zero; 6067 if (Value.isUnsigned() || Value.isNonNegative()) { 6068 if (Value == 0) { 6069 LiteralOrBoolConstant = 6070 ConstantIsBoolLiteral ? CXXBoolLiteralFalse : LiteralConstant; 6071 ConstVal = Zero; 6072 } else if (Value == 1) { 6073 LiteralOrBoolConstant = 6074 ConstantIsBoolLiteral ? CXXBoolLiteralTrue : LiteralConstant; 6075 ConstVal = One; 6076 } else { 6077 LiteralOrBoolConstant = LiteralConstant; 6078 ConstVal = GT_One; 6079 } 6080 } else { 6081 ConstVal = LT_Zero; 6082 } 6083 6084 CompareBoolWithConstantResult CmpRes; 6085 6086 switch (op) { 6087 case BO_LT: 6088 CmpRes = TruthTable.BO_LT_OP[RhsConstant][ConstVal]; 6089 break; 6090 case BO_GT: 6091 CmpRes = TruthTable.BO_GT_OP[RhsConstant][ConstVal]; 6092 break; 6093 case BO_LE: 6094 CmpRes = TruthTable.BO_LE_OP[RhsConstant][ConstVal]; 6095 break; 6096 case BO_GE: 6097 CmpRes = TruthTable.BO_GE_OP[RhsConstant][ConstVal]; 6098 break; 6099 case BO_EQ: 6100 CmpRes = TruthTable.BO_EQ_OP[RhsConstant][ConstVal]; 6101 break; 6102 case BO_NE: 6103 CmpRes = TruthTable.BO_NE_OP[RhsConstant][ConstVal]; 6104 break; 6105 default: 6106 CmpRes = Unkwn; 6107 break; 6108 } 6109 6110 if (CmpRes == AFals) { 6111 IsTrue = false; 6112 } else if (CmpRes == ATrue) { 6113 IsTrue = true; 6114 } else { 6115 return; 6116 } 6117 } 6118 6119 // If this is a comparison to an enum constant, include that 6120 // constant in the diagnostic. 6121 const EnumConstantDecl *ED = nullptr; 6122 if (const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(Constant)) 6123 ED = dyn_cast<EnumConstantDecl>(DR->getDecl()); 6124 6125 SmallString<64> PrettySourceValue; 6126 llvm::raw_svector_ostream OS(PrettySourceValue); 6127 if (ED) 6128 OS << '\'' << *ED << "' (" << Value << ")"; 6129 else 6130 OS << Value; 6131 6132 S.DiagRuntimeBehavior( 6133 E->getOperatorLoc(), E, 6134 S.PDiag(diag::warn_out_of_range_compare) 6135 << OS.str() << LiteralOrBoolConstant 6136 << OtherT << (OtherIsBooleanType && !OtherT->isBooleanType()) << IsTrue 6137 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange()); 6138 } 6139 6140 /// Analyze the operands of the given comparison. Implements the 6141 /// fallback case from AnalyzeComparison. 6142 static void AnalyzeImpConvsInComparison(Sema &S, BinaryOperator *E) { 6143 AnalyzeImplicitConversions(S, E->getLHS(), E->getOperatorLoc()); 6144 AnalyzeImplicitConversions(S, E->getRHS(), E->getOperatorLoc()); 6145 } 6146 6147 /// \brief Implements -Wsign-compare. 6148 /// 6149 /// \param E the binary operator to check for warnings 6150 static void AnalyzeComparison(Sema &S, BinaryOperator *E) { 6151 // The type the comparison is being performed in. 6152 QualType T = E->getLHS()->getType(); 6153 6154 // Only analyze comparison operators where both sides have been converted to 6155 // the same type. 6156 if (!S.Context.hasSameUnqualifiedType(T, E->getRHS()->getType())) 6157 return AnalyzeImpConvsInComparison(S, E); 6158 6159 // Don't analyze value-dependent comparisons directly. 6160 if (E->isValueDependent()) 6161 return AnalyzeImpConvsInComparison(S, E); 6162 6163 Expr *LHS = E->getLHS()->IgnoreParenImpCasts(); 6164 Expr *RHS = E->getRHS()->IgnoreParenImpCasts(); 6165 6166 bool IsComparisonConstant = false; 6167 6168 // Check whether an integer constant comparison results in a value 6169 // of 'true' or 'false'. 6170 if (T->isIntegralType(S.Context)) { 6171 llvm::APSInt RHSValue; 6172 bool IsRHSIntegralLiteral = 6173 RHS->isIntegerConstantExpr(RHSValue, S.Context); 6174 llvm::APSInt LHSValue; 6175 bool IsLHSIntegralLiteral = 6176 LHS->isIntegerConstantExpr(LHSValue, S.Context); 6177 if (IsRHSIntegralLiteral && !IsLHSIntegralLiteral) 6178 DiagnoseOutOfRangeComparison(S, E, RHS, LHS, RHSValue, true); 6179 else if (!IsRHSIntegralLiteral && IsLHSIntegralLiteral) 6180 DiagnoseOutOfRangeComparison(S, E, LHS, RHS, LHSValue, false); 6181 else 6182 IsComparisonConstant = 6183 (IsRHSIntegralLiteral && IsLHSIntegralLiteral); 6184 } else if (!T->hasUnsignedIntegerRepresentation()) 6185 IsComparisonConstant = E->isIntegerConstantExpr(S.Context); 6186 6187 // We don't do anything special if this isn't an unsigned integral 6188 // comparison: we're only interested in integral comparisons, and 6189 // signed comparisons only happen in cases we don't care to warn about. 6190 // 6191 // We also don't care about value-dependent expressions or expressions 6192 // whose result is a constant. 6193 if (!T->hasUnsignedIntegerRepresentation() || IsComparisonConstant) 6194 return AnalyzeImpConvsInComparison(S, E); 6195 6196 // Check to see if one of the (unmodified) operands is of different 6197 // signedness. 6198 Expr *signedOperand, *unsignedOperand; 6199 if (LHS->getType()->hasSignedIntegerRepresentation()) { 6200 assert(!RHS->getType()->hasSignedIntegerRepresentation() && 6201 "unsigned comparison between two signed integer expressions?"); 6202 signedOperand = LHS; 6203 unsignedOperand = RHS; 6204 } else if (RHS->getType()->hasSignedIntegerRepresentation()) { 6205 signedOperand = RHS; 6206 unsignedOperand = LHS; 6207 } else { 6208 CheckTrivialUnsignedComparison(S, E); 6209 return AnalyzeImpConvsInComparison(S, E); 6210 } 6211 6212 // Otherwise, calculate the effective range of the signed operand. 6213 IntRange signedRange = GetExprRange(S.Context, signedOperand); 6214 6215 // Go ahead and analyze implicit conversions in the operands. Note 6216 // that we skip the implicit conversions on both sides. 6217 AnalyzeImplicitConversions(S, LHS, E->getOperatorLoc()); 6218 AnalyzeImplicitConversions(S, RHS, E->getOperatorLoc()); 6219 6220 // If the signed range is non-negative, -Wsign-compare won't fire, 6221 // but we should still check for comparisons which are always true 6222 // or false. 6223 if (signedRange.NonNegative) 6224 return CheckTrivialUnsignedComparison(S, E); 6225 6226 // For (in)equality comparisons, if the unsigned operand is a 6227 // constant which cannot collide with a overflowed signed operand, 6228 // then reinterpreting the signed operand as unsigned will not 6229 // change the result of the comparison. 6230 if (E->isEqualityOp()) { 6231 unsigned comparisonWidth = S.Context.getIntWidth(T); 6232 IntRange unsignedRange = GetExprRange(S.Context, unsignedOperand); 6233 6234 // We should never be unable to prove that the unsigned operand is 6235 // non-negative. 6236 assert(unsignedRange.NonNegative && "unsigned range includes negative?"); 6237 6238 if (unsignedRange.Width < comparisonWidth) 6239 return; 6240 } 6241 6242 S.DiagRuntimeBehavior(E->getOperatorLoc(), E, 6243 S.PDiag(diag::warn_mixed_sign_comparison) 6244 << LHS->getType() << RHS->getType() 6245 << LHS->getSourceRange() << RHS->getSourceRange()); 6246 } 6247 6248 /// Analyzes an attempt to assign the given value to a bitfield. 6249 /// 6250 /// Returns true if there was something fishy about the attempt. 6251 static bool AnalyzeBitFieldAssignment(Sema &S, FieldDecl *Bitfield, Expr *Init, 6252 SourceLocation InitLoc) { 6253 assert(Bitfield->isBitField()); 6254 if (Bitfield->isInvalidDecl()) 6255 return false; 6256 6257 // White-list bool bitfields. 6258 if (Bitfield->getType()->isBooleanType()) 6259 return false; 6260 6261 // Ignore value- or type-dependent expressions. 6262 if (Bitfield->getBitWidth()->isValueDependent() || 6263 Bitfield->getBitWidth()->isTypeDependent() || 6264 Init->isValueDependent() || 6265 Init->isTypeDependent()) 6266 return false; 6267 6268 Expr *OriginalInit = Init->IgnoreParenImpCasts(); 6269 6270 llvm::APSInt Value; 6271 if (!OriginalInit->EvaluateAsInt(Value, S.Context, Expr::SE_AllowSideEffects)) 6272 return false; 6273 6274 unsigned OriginalWidth = Value.getBitWidth(); 6275 unsigned FieldWidth = Bitfield->getBitWidthValue(S.Context); 6276 6277 if (OriginalWidth <= FieldWidth) 6278 return false; 6279 6280 // Compute the value which the bitfield will contain. 6281 llvm::APSInt TruncatedValue = Value.trunc(FieldWidth); 6282 TruncatedValue.setIsSigned(Bitfield->getType()->isSignedIntegerType()); 6283 6284 // Check whether the stored value is equal to the original value. 6285 TruncatedValue = TruncatedValue.extend(OriginalWidth); 6286 if (llvm::APSInt::isSameValue(Value, TruncatedValue)) 6287 return false; 6288 6289 // Special-case bitfields of width 1: booleans are naturally 0/1, and 6290 // therefore don't strictly fit into a signed bitfield of width 1. 6291 if (FieldWidth == 1 && Value == 1) 6292 return false; 6293 6294 std::string PrettyValue = Value.toString(10); 6295 std::string PrettyTrunc = TruncatedValue.toString(10); 6296 6297 S.Diag(InitLoc, diag::warn_impcast_bitfield_precision_constant) 6298 << PrettyValue << PrettyTrunc << OriginalInit->getType() 6299 << Init->getSourceRange(); 6300 6301 return true; 6302 } 6303 6304 /// Analyze the given simple or compound assignment for warning-worthy 6305 /// operations. 6306 static void AnalyzeAssignment(Sema &S, BinaryOperator *E) { 6307 // Just recurse on the LHS. 6308 AnalyzeImplicitConversions(S, E->getLHS(), E->getOperatorLoc()); 6309 6310 // We want to recurse on the RHS as normal unless we're assigning to 6311 // a bitfield. 6312 if (FieldDecl *Bitfield = E->getLHS()->getSourceBitField()) { 6313 if (AnalyzeBitFieldAssignment(S, Bitfield, E->getRHS(), 6314 E->getOperatorLoc())) { 6315 // Recurse, ignoring any implicit conversions on the RHS. 6316 return AnalyzeImplicitConversions(S, E->getRHS()->IgnoreParenImpCasts(), 6317 E->getOperatorLoc()); 6318 } 6319 } 6320 6321 AnalyzeImplicitConversions(S, E->getRHS(), E->getOperatorLoc()); 6322 } 6323 6324 /// Diagnose an implicit cast; purely a helper for CheckImplicitConversion. 6325 static void DiagnoseImpCast(Sema &S, Expr *E, QualType SourceType, QualType T, 6326 SourceLocation CContext, unsigned diag, 6327 bool pruneControlFlow = false) { 6328 if (pruneControlFlow) { 6329 S.DiagRuntimeBehavior(E->getExprLoc(), E, 6330 S.PDiag(diag) 6331 << SourceType << T << E->getSourceRange() 6332 << SourceRange(CContext)); 6333 return; 6334 } 6335 S.Diag(E->getExprLoc(), diag) 6336 << SourceType << T << E->getSourceRange() << SourceRange(CContext); 6337 } 6338 6339 /// Diagnose an implicit cast; purely a helper for CheckImplicitConversion. 6340 static void DiagnoseImpCast(Sema &S, Expr *E, QualType T, 6341 SourceLocation CContext, unsigned diag, 6342 bool pruneControlFlow = false) { 6343 DiagnoseImpCast(S, E, E->getType(), T, CContext, diag, pruneControlFlow); 6344 } 6345 6346 /// Diagnose an implicit cast from a literal expression. Does not warn when the 6347 /// cast wouldn't lose information. 6348 void DiagnoseFloatingLiteralImpCast(Sema &S, FloatingLiteral *FL, QualType T, 6349 SourceLocation CContext) { 6350 // Try to convert the literal exactly to an integer. If we can, don't warn. 6351 bool isExact = false; 6352 const llvm::APFloat &Value = FL->getValue(); 6353 llvm::APSInt IntegerValue(S.Context.getIntWidth(T), 6354 T->hasUnsignedIntegerRepresentation()); 6355 if (Value.convertToInteger(IntegerValue, 6356 llvm::APFloat::rmTowardZero, &isExact) 6357 == llvm::APFloat::opOK && isExact) 6358 return; 6359 6360 // FIXME: Force the precision of the source value down so we don't print 6361 // digits which are usually useless (we don't really care here if we 6362 // truncate a digit by accident in edge cases). Ideally, APFloat::toString 6363 // would automatically print the shortest representation, but it's a bit 6364 // tricky to implement. 6365 SmallString<16> PrettySourceValue; 6366 unsigned precision = llvm::APFloat::semanticsPrecision(Value.getSemantics()); 6367 precision = (precision * 59 + 195) / 196; 6368 Value.toString(PrettySourceValue, precision); 6369 6370 SmallString<16> PrettyTargetValue; 6371 if (T->isSpecificBuiltinType(BuiltinType::Bool)) 6372 PrettyTargetValue = IntegerValue == 0 ? "false" : "true"; 6373 else 6374 IntegerValue.toString(PrettyTargetValue); 6375 6376 S.Diag(FL->getExprLoc(), diag::warn_impcast_literal_float_to_integer) 6377 << FL->getType() << T.getUnqualifiedType() << PrettySourceValue 6378 << PrettyTargetValue << FL->getSourceRange() << SourceRange(CContext); 6379 } 6380 6381 std::string PrettyPrintInRange(const llvm::APSInt &Value, IntRange Range) { 6382 if (!Range.Width) return "0"; 6383 6384 llvm::APSInt ValueInRange = Value; 6385 ValueInRange.setIsSigned(!Range.NonNegative); 6386 ValueInRange = ValueInRange.trunc(Range.Width); 6387 return ValueInRange.toString(10); 6388 } 6389 6390 static bool IsImplicitBoolFloatConversion(Sema &S, Expr *Ex, bool ToBool) { 6391 if (!isa<ImplicitCastExpr>(Ex)) 6392 return false; 6393 6394 Expr *InnerE = Ex->IgnoreParenImpCasts(); 6395 const Type *Target = S.Context.getCanonicalType(Ex->getType()).getTypePtr(); 6396 const Type *Source = 6397 S.Context.getCanonicalType(InnerE->getType()).getTypePtr(); 6398 if (Target->isDependentType()) 6399 return false; 6400 6401 const BuiltinType *FloatCandidateBT = 6402 dyn_cast<BuiltinType>(ToBool ? Source : Target); 6403 const Type *BoolCandidateType = ToBool ? Target : Source; 6404 6405 return (BoolCandidateType->isSpecificBuiltinType(BuiltinType::Bool) && 6406 FloatCandidateBT && (FloatCandidateBT->isFloatingPoint())); 6407 } 6408 6409 void CheckImplicitArgumentConversions(Sema &S, CallExpr *TheCall, 6410 SourceLocation CC) { 6411 unsigned NumArgs = TheCall->getNumArgs(); 6412 for (unsigned i = 0; i < NumArgs; ++i) { 6413 Expr *CurrA = TheCall->getArg(i); 6414 if (!IsImplicitBoolFloatConversion(S, CurrA, true)) 6415 continue; 6416 6417 bool IsSwapped = ((i > 0) && 6418 IsImplicitBoolFloatConversion(S, TheCall->getArg(i - 1), false)); 6419 IsSwapped |= ((i < (NumArgs - 1)) && 6420 IsImplicitBoolFloatConversion(S, TheCall->getArg(i + 1), false)); 6421 if (IsSwapped) { 6422 // Warn on this floating-point to bool conversion. 6423 DiagnoseImpCast(S, CurrA->IgnoreParenImpCasts(), 6424 CurrA->getType(), CC, 6425 diag::warn_impcast_floating_point_to_bool); 6426 } 6427 } 6428 } 6429 6430 static void DiagnoseNullConversion(Sema &S, Expr *E, QualType T, 6431 SourceLocation CC) { 6432 if (S.Diags.isIgnored(diag::warn_impcast_null_pointer_to_integer, 6433 E->getExprLoc())) 6434 return; 6435 6436 // Check for NULL (GNUNull) or nullptr (CXX11_nullptr). 6437 const Expr::NullPointerConstantKind NullKind = 6438 E->isNullPointerConstant(S.Context, Expr::NPC_ValueDependentIsNotNull); 6439 if (NullKind != Expr::NPCK_GNUNull && NullKind != Expr::NPCK_CXX11_nullptr) 6440 return; 6441 6442 // Return if target type is a safe conversion. 6443 if (T->isAnyPointerType() || T->isBlockPointerType() || 6444 T->isMemberPointerType() || !T->isScalarType() || T->isNullPtrType()) 6445 return; 6446 6447 SourceLocation Loc = E->getSourceRange().getBegin(); 6448 6449 // __null is usually wrapped in a macro. Go up a macro if that is the case. 6450 if (NullKind == Expr::NPCK_GNUNull) { 6451 if (Loc.isMacroID()) 6452 Loc = S.SourceMgr.getImmediateExpansionRange(Loc).first; 6453 } 6454 6455 // Only warn if the null and context location are in the same macro expansion. 6456 if (S.SourceMgr.getFileID(Loc) != S.SourceMgr.getFileID(CC)) 6457 return; 6458 6459 S.Diag(Loc, diag::warn_impcast_null_pointer_to_integer) 6460 << (NullKind == Expr::NPCK_CXX11_nullptr) << T << clang::SourceRange(CC) 6461 << FixItHint::CreateReplacement(Loc, 6462 S.getFixItZeroLiteralForType(T, Loc)); 6463 } 6464 6465 void CheckImplicitConversion(Sema &S, Expr *E, QualType T, 6466 SourceLocation CC, bool *ICContext = nullptr) { 6467 if (E->isTypeDependent() || E->isValueDependent()) return; 6468 6469 const Type *Source = S.Context.getCanonicalType(E->getType()).getTypePtr(); 6470 const Type *Target = S.Context.getCanonicalType(T).getTypePtr(); 6471 if (Source == Target) return; 6472 if (Target->isDependentType()) return; 6473 6474 // If the conversion context location is invalid don't complain. We also 6475 // don't want to emit a warning if the issue occurs from the expansion of 6476 // a system macro. The problem is that 'getSpellingLoc()' is slow, so we 6477 // delay this check as long as possible. Once we detect we are in that 6478 // scenario, we just return. 6479 if (CC.isInvalid()) 6480 return; 6481 6482 // Diagnose implicit casts to bool. 6483 if (Target->isSpecificBuiltinType(BuiltinType::Bool)) { 6484 if (isa<StringLiteral>(E)) 6485 // Warn on string literal to bool. Checks for string literals in logical 6486 // and expressions, for instance, assert(0 && "error here"), are 6487 // prevented by a check in AnalyzeImplicitConversions(). 6488 return DiagnoseImpCast(S, E, T, CC, 6489 diag::warn_impcast_string_literal_to_bool); 6490 if (isa<ObjCStringLiteral>(E) || isa<ObjCArrayLiteral>(E) || 6491 isa<ObjCDictionaryLiteral>(E) || isa<ObjCBoxedExpr>(E)) { 6492 // This covers the literal expressions that evaluate to Objective-C 6493 // objects. 6494 return DiagnoseImpCast(S, E, T, CC, 6495 diag::warn_impcast_objective_c_literal_to_bool); 6496 } 6497 if (Source->isPointerType() || Source->canDecayToPointerType()) { 6498 // Warn on pointer to bool conversion that is always true. 6499 S.DiagnoseAlwaysNonNullPointer(E, Expr::NPCK_NotNull, /*IsEqual*/ false, 6500 SourceRange(CC)); 6501 } 6502 } 6503 6504 // Strip vector types. 6505 if (isa<VectorType>(Source)) { 6506 if (!isa<VectorType>(Target)) { 6507 if (S.SourceMgr.isInSystemMacro(CC)) 6508 return; 6509 return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_vector_scalar); 6510 } 6511 6512 // If the vector cast is cast between two vectors of the same size, it is 6513 // a bitcast, not a conversion. 6514 if (S.Context.getTypeSize(Source) == S.Context.getTypeSize(Target)) 6515 return; 6516 6517 Source = cast<VectorType>(Source)->getElementType().getTypePtr(); 6518 Target = cast<VectorType>(Target)->getElementType().getTypePtr(); 6519 } 6520 if (auto VecTy = dyn_cast<VectorType>(Target)) 6521 Target = VecTy->getElementType().getTypePtr(); 6522 6523 // Strip complex types. 6524 if (isa<ComplexType>(Source)) { 6525 if (!isa<ComplexType>(Target)) { 6526 if (S.SourceMgr.isInSystemMacro(CC)) 6527 return; 6528 6529 return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_complex_scalar); 6530 } 6531 6532 Source = cast<ComplexType>(Source)->getElementType().getTypePtr(); 6533 Target = cast<ComplexType>(Target)->getElementType().getTypePtr(); 6534 } 6535 6536 const BuiltinType *SourceBT = dyn_cast<BuiltinType>(Source); 6537 const BuiltinType *TargetBT = dyn_cast<BuiltinType>(Target); 6538 6539 // If the source is floating point... 6540 if (SourceBT && SourceBT->isFloatingPoint()) { 6541 // ...and the target is floating point... 6542 if (TargetBT && TargetBT->isFloatingPoint()) { 6543 // ...then warn if we're dropping FP rank. 6544 6545 // Builtin FP kinds are ordered by increasing FP rank. 6546 if (SourceBT->getKind() > TargetBT->getKind()) { 6547 // Don't warn about float constants that are precisely 6548 // representable in the target type. 6549 Expr::EvalResult result; 6550 if (E->EvaluateAsRValue(result, S.Context)) { 6551 // Value might be a float, a float vector, or a float complex. 6552 if (IsSameFloatAfterCast(result.Val, 6553 S.Context.getFloatTypeSemantics(QualType(TargetBT, 0)), 6554 S.Context.getFloatTypeSemantics(QualType(SourceBT, 0)))) 6555 return; 6556 } 6557 6558 if (S.SourceMgr.isInSystemMacro(CC)) 6559 return; 6560 6561 DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_float_precision); 6562 } 6563 return; 6564 } 6565 6566 // If the target is integral, always warn. 6567 if (TargetBT && TargetBT->isInteger()) { 6568 if (S.SourceMgr.isInSystemMacro(CC)) 6569 return; 6570 6571 Expr *InnerE = E->IgnoreParenImpCasts(); 6572 // We also want to warn on, e.g., "int i = -1.234" 6573 if (UnaryOperator *UOp = dyn_cast<UnaryOperator>(InnerE)) 6574 if (UOp->getOpcode() == UO_Minus || UOp->getOpcode() == UO_Plus) 6575 InnerE = UOp->getSubExpr()->IgnoreParenImpCasts(); 6576 6577 if (FloatingLiteral *FL = dyn_cast<FloatingLiteral>(InnerE)) { 6578 DiagnoseFloatingLiteralImpCast(S, FL, T, CC); 6579 } else { 6580 DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_float_integer); 6581 } 6582 } 6583 6584 // If the target is bool, warn if expr is a function or method call. 6585 if (Target->isSpecificBuiltinType(BuiltinType::Bool) && 6586 isa<CallExpr>(E)) { 6587 // Check last argument of function call to see if it is an 6588 // implicit cast from a type matching the type the result 6589 // is being cast to. 6590 CallExpr *CEx = cast<CallExpr>(E); 6591 unsigned NumArgs = CEx->getNumArgs(); 6592 if (NumArgs > 0) { 6593 Expr *LastA = CEx->getArg(NumArgs - 1); 6594 Expr *InnerE = LastA->IgnoreParenImpCasts(); 6595 const Type *InnerType = 6596 S.Context.getCanonicalType(InnerE->getType()).getTypePtr(); 6597 if (isa<ImplicitCastExpr>(LastA) && (InnerType == Target)) { 6598 // Warn on this floating-point to bool conversion 6599 DiagnoseImpCast(S, E, T, CC, 6600 diag::warn_impcast_floating_point_to_bool); 6601 } 6602 } 6603 } 6604 return; 6605 } 6606 6607 DiagnoseNullConversion(S, E, T, CC); 6608 6609 if (!Source->isIntegerType() || !Target->isIntegerType()) 6610 return; 6611 6612 // TODO: remove this early return once the false positives for constant->bool 6613 // in templates, macros, etc, are reduced or removed. 6614 if (Target->isSpecificBuiltinType(BuiltinType::Bool)) 6615 return; 6616 6617 IntRange SourceRange = GetExprRange(S.Context, E); 6618 IntRange TargetRange = IntRange::forTargetOfCanonicalType(S.Context, Target); 6619 6620 if (SourceRange.Width > TargetRange.Width) { 6621 // If the source is a constant, use a default-on diagnostic. 6622 // TODO: this should happen for bitfield stores, too. 6623 llvm::APSInt Value(32); 6624 if (E->isIntegerConstantExpr(Value, S.Context)) { 6625 if (S.SourceMgr.isInSystemMacro(CC)) 6626 return; 6627 6628 std::string PrettySourceValue = Value.toString(10); 6629 std::string PrettyTargetValue = PrettyPrintInRange(Value, TargetRange); 6630 6631 S.DiagRuntimeBehavior(E->getExprLoc(), E, 6632 S.PDiag(diag::warn_impcast_integer_precision_constant) 6633 << PrettySourceValue << PrettyTargetValue 6634 << E->getType() << T << E->getSourceRange() 6635 << clang::SourceRange(CC)); 6636 return; 6637 } 6638 6639 // People want to build with -Wshorten-64-to-32 and not -Wconversion. 6640 if (S.SourceMgr.isInSystemMacro(CC)) 6641 return; 6642 6643 if (TargetRange.Width == 32 && S.Context.getIntWidth(E->getType()) == 64) 6644 return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_integer_64_32, 6645 /* pruneControlFlow */ true); 6646 return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_integer_precision); 6647 } 6648 6649 if ((TargetRange.NonNegative && !SourceRange.NonNegative) || 6650 (!TargetRange.NonNegative && SourceRange.NonNegative && 6651 SourceRange.Width == TargetRange.Width)) { 6652 6653 if (S.SourceMgr.isInSystemMacro(CC)) 6654 return; 6655 6656 unsigned DiagID = diag::warn_impcast_integer_sign; 6657 6658 // Traditionally, gcc has warned about this under -Wsign-compare. 6659 // We also want to warn about it in -Wconversion. 6660 // So if -Wconversion is off, use a completely identical diagnostic 6661 // in the sign-compare group. 6662 // The conditional-checking code will 6663 if (ICContext) { 6664 DiagID = diag::warn_impcast_integer_sign_conditional; 6665 *ICContext = true; 6666 } 6667 6668 return DiagnoseImpCast(S, E, T, CC, DiagID); 6669 } 6670 6671 // Diagnose conversions between different enumeration types. 6672 // In C, we pretend that the type of an EnumConstantDecl is its enumeration 6673 // type, to give us better diagnostics. 6674 QualType SourceType = E->getType(); 6675 if (!S.getLangOpts().CPlusPlus) { 6676 if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) 6677 if (EnumConstantDecl *ECD = dyn_cast<EnumConstantDecl>(DRE->getDecl())) { 6678 EnumDecl *Enum = cast<EnumDecl>(ECD->getDeclContext()); 6679 SourceType = S.Context.getTypeDeclType(Enum); 6680 Source = S.Context.getCanonicalType(SourceType).getTypePtr(); 6681 } 6682 } 6683 6684 if (const EnumType *SourceEnum = Source->getAs<EnumType>()) 6685 if (const EnumType *TargetEnum = Target->getAs<EnumType>()) 6686 if (SourceEnum->getDecl()->hasNameForLinkage() && 6687 TargetEnum->getDecl()->hasNameForLinkage() && 6688 SourceEnum != TargetEnum) { 6689 if (S.SourceMgr.isInSystemMacro(CC)) 6690 return; 6691 6692 return DiagnoseImpCast(S, E, SourceType, T, CC, 6693 diag::warn_impcast_different_enum_types); 6694 } 6695 6696 return; 6697 } 6698 6699 void CheckConditionalOperator(Sema &S, ConditionalOperator *E, 6700 SourceLocation CC, QualType T); 6701 6702 void CheckConditionalOperand(Sema &S, Expr *E, QualType T, 6703 SourceLocation CC, bool &ICContext) { 6704 E = E->IgnoreParenImpCasts(); 6705 6706 if (isa<ConditionalOperator>(E)) 6707 return CheckConditionalOperator(S, cast<ConditionalOperator>(E), CC, T); 6708 6709 AnalyzeImplicitConversions(S, E, CC); 6710 if (E->getType() != T) 6711 return CheckImplicitConversion(S, E, T, CC, &ICContext); 6712 return; 6713 } 6714 6715 void CheckConditionalOperator(Sema &S, ConditionalOperator *E, 6716 SourceLocation CC, QualType T) { 6717 AnalyzeImplicitConversions(S, E->getCond(), E->getQuestionLoc()); 6718 6719 bool Suspicious = false; 6720 CheckConditionalOperand(S, E->getTrueExpr(), T, CC, Suspicious); 6721 CheckConditionalOperand(S, E->getFalseExpr(), T, CC, Suspicious); 6722 6723 // If -Wconversion would have warned about either of the candidates 6724 // for a signedness conversion to the context type... 6725 if (!Suspicious) return; 6726 6727 // ...but it's currently ignored... 6728 if (!S.Diags.isIgnored(diag::warn_impcast_integer_sign_conditional, CC)) 6729 return; 6730 6731 // ...then check whether it would have warned about either of the 6732 // candidates for a signedness conversion to the condition type. 6733 if (E->getType() == T) return; 6734 6735 Suspicious = false; 6736 CheckImplicitConversion(S, E->getTrueExpr()->IgnoreParenImpCasts(), 6737 E->getType(), CC, &Suspicious); 6738 if (!Suspicious) 6739 CheckImplicitConversion(S, E->getFalseExpr()->IgnoreParenImpCasts(), 6740 E->getType(), CC, &Suspicious); 6741 } 6742 6743 /// CheckBoolLikeConversion - Check conversion of given expression to boolean. 6744 /// Input argument E is a logical expression. 6745 static void CheckBoolLikeConversion(Sema &S, Expr *E, SourceLocation CC) { 6746 if (S.getLangOpts().Bool) 6747 return; 6748 CheckImplicitConversion(S, E->IgnoreParenImpCasts(), S.Context.BoolTy, CC); 6749 } 6750 6751 /// AnalyzeImplicitConversions - Find and report any interesting 6752 /// implicit conversions in the given expression. There are a couple 6753 /// of competing diagnostics here, -Wconversion and -Wsign-compare. 6754 void AnalyzeImplicitConversions(Sema &S, Expr *OrigE, SourceLocation CC) { 6755 QualType T = OrigE->getType(); 6756 Expr *E = OrigE->IgnoreParenImpCasts(); 6757 6758 if (E->isTypeDependent() || E->isValueDependent()) 6759 return; 6760 6761 // For conditional operators, we analyze the arguments as if they 6762 // were being fed directly into the output. 6763 if (isa<ConditionalOperator>(E)) { 6764 ConditionalOperator *CO = cast<ConditionalOperator>(E); 6765 CheckConditionalOperator(S, CO, CC, T); 6766 return; 6767 } 6768 6769 // Check implicit argument conversions for function calls. 6770 if (CallExpr *Call = dyn_cast<CallExpr>(E)) 6771 CheckImplicitArgumentConversions(S, Call, CC); 6772 6773 // Go ahead and check any implicit conversions we might have skipped. 6774 // The non-canonical typecheck is just an optimization; 6775 // CheckImplicitConversion will filter out dead implicit conversions. 6776 if (E->getType() != T) 6777 CheckImplicitConversion(S, E, T, CC); 6778 6779 // Now continue drilling into this expression. 6780 6781 if (PseudoObjectExpr * POE = dyn_cast<PseudoObjectExpr>(E)) { 6782 if (POE->getResultExpr()) 6783 E = POE->getResultExpr(); 6784 } 6785 6786 if (const OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(E)) 6787 return AnalyzeImplicitConversions(S, OVE->getSourceExpr(), CC); 6788 6789 // Skip past explicit casts. 6790 if (isa<ExplicitCastExpr>(E)) { 6791 E = cast<ExplicitCastExpr>(E)->getSubExpr()->IgnoreParenImpCasts(); 6792 return AnalyzeImplicitConversions(S, E, CC); 6793 } 6794 6795 if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) { 6796 // Do a somewhat different check with comparison operators. 6797 if (BO->isComparisonOp()) 6798 return AnalyzeComparison(S, BO); 6799 6800 // And with simple assignments. 6801 if (BO->getOpcode() == BO_Assign) 6802 return AnalyzeAssignment(S, BO); 6803 } 6804 6805 // These break the otherwise-useful invariant below. Fortunately, 6806 // we don't really need to recurse into them, because any internal 6807 // expressions should have been analyzed already when they were 6808 // built into statements. 6809 if (isa<StmtExpr>(E)) return; 6810 6811 // Don't descend into unevaluated contexts. 6812 if (isa<UnaryExprOrTypeTraitExpr>(E)) return; 6813 6814 // Now just recurse over the expression's children. 6815 CC = E->getExprLoc(); 6816 BinaryOperator *BO = dyn_cast<BinaryOperator>(E); 6817 bool IsLogicalAndOperator = BO && BO->getOpcode() == BO_LAnd; 6818 for (Stmt::child_range I = E->children(); I; ++I) { 6819 Expr *ChildExpr = dyn_cast_or_null<Expr>(*I); 6820 if (!ChildExpr) 6821 continue; 6822 6823 if (IsLogicalAndOperator && 6824 isa<StringLiteral>(ChildExpr->IgnoreParenImpCasts())) 6825 // Ignore checking string literals that are in logical and operators. 6826 // This is a common pattern for asserts. 6827 continue; 6828 AnalyzeImplicitConversions(S, ChildExpr, CC); 6829 } 6830 6831 if (BO && BO->isLogicalOp()) { 6832 Expr *SubExpr = BO->getLHS()->IgnoreParenImpCasts(); 6833 if (!IsLogicalAndOperator || !isa<StringLiteral>(SubExpr)) 6834 ::CheckBoolLikeConversion(S, SubExpr, BO->getExprLoc()); 6835 6836 SubExpr = BO->getRHS()->IgnoreParenImpCasts(); 6837 if (!IsLogicalAndOperator || !isa<StringLiteral>(SubExpr)) 6838 ::CheckBoolLikeConversion(S, SubExpr, BO->getExprLoc()); 6839 } 6840 6841 if (const UnaryOperator *U = dyn_cast<UnaryOperator>(E)) 6842 if (U->getOpcode() == UO_LNot) 6843 ::CheckBoolLikeConversion(S, U->getSubExpr(), CC); 6844 } 6845 6846 } // end anonymous namespace 6847 6848 enum { 6849 AddressOf, 6850 FunctionPointer, 6851 ArrayPointer 6852 }; 6853 6854 // Helper function for Sema::DiagnoseAlwaysNonNullPointer. 6855 // Returns true when emitting a warning about taking the address of a reference. 6856 static bool CheckForReference(Sema &SemaRef, const Expr *E, 6857 PartialDiagnostic PD) { 6858 E = E->IgnoreParenImpCasts(); 6859 6860 const FunctionDecl *FD = nullptr; 6861 6862 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) { 6863 if (!DRE->getDecl()->getType()->isReferenceType()) 6864 return false; 6865 } else if (const MemberExpr *M = dyn_cast<MemberExpr>(E)) { 6866 if (!M->getMemberDecl()->getType()->isReferenceType()) 6867 return false; 6868 } else if (const CallExpr *Call = dyn_cast<CallExpr>(E)) { 6869 if (!Call->getCallReturnType()->isReferenceType()) 6870 return false; 6871 FD = Call->getDirectCallee(); 6872 } else { 6873 return false; 6874 } 6875 6876 SemaRef.Diag(E->getExprLoc(), PD); 6877 6878 // If possible, point to location of function. 6879 if (FD) { 6880 SemaRef.Diag(FD->getLocation(), diag::note_reference_is_return_value) << FD; 6881 } 6882 6883 return true; 6884 } 6885 6886 // Returns true if the SourceLocation is expanded from any macro body. 6887 // Returns false if the SourceLocation is invalid, is from not in a macro 6888 // expansion, or is from expanded from a top-level macro argument. 6889 static bool IsInAnyMacroBody(const SourceManager &SM, SourceLocation Loc) { 6890 if (Loc.isInvalid()) 6891 return false; 6892 6893 while (Loc.isMacroID()) { 6894 if (SM.isMacroBodyExpansion(Loc)) 6895 return true; 6896 Loc = SM.getImmediateMacroCallerLoc(Loc); 6897 } 6898 6899 return false; 6900 } 6901 6902 /// \brief Diagnose pointers that are always non-null. 6903 /// \param E the expression containing the pointer 6904 /// \param NullKind NPCK_NotNull if E is a cast to bool, otherwise, E is 6905 /// compared to a null pointer 6906 /// \param IsEqual True when the comparison is equal to a null pointer 6907 /// \param Range Extra SourceRange to highlight in the diagnostic 6908 void Sema::DiagnoseAlwaysNonNullPointer(Expr *E, 6909 Expr::NullPointerConstantKind NullKind, 6910 bool IsEqual, SourceRange Range) { 6911 if (!E) 6912 return; 6913 6914 // Don't warn inside macros. 6915 if (E->getExprLoc().isMacroID()) { 6916 const SourceManager &SM = getSourceManager(); 6917 if (IsInAnyMacroBody(SM, E->getExprLoc()) || 6918 IsInAnyMacroBody(SM, Range.getBegin())) 6919 return; 6920 } 6921 E = E->IgnoreImpCasts(); 6922 6923 const bool IsCompare = NullKind != Expr::NPCK_NotNull; 6924 6925 if (isa<CXXThisExpr>(E)) { 6926 unsigned DiagID = IsCompare ? diag::warn_this_null_compare 6927 : diag::warn_this_bool_conversion; 6928 Diag(E->getExprLoc(), DiagID) << E->getSourceRange() << Range << IsEqual; 6929 return; 6930 } 6931 6932 bool IsAddressOf = false; 6933 6934 if (UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) { 6935 if (UO->getOpcode() != UO_AddrOf) 6936 return; 6937 IsAddressOf = true; 6938 E = UO->getSubExpr(); 6939 } 6940 6941 if (IsAddressOf) { 6942 unsigned DiagID = IsCompare 6943 ? diag::warn_address_of_reference_null_compare 6944 : diag::warn_address_of_reference_bool_conversion; 6945 PartialDiagnostic PD = PDiag(DiagID) << E->getSourceRange() << Range 6946 << IsEqual; 6947 if (CheckForReference(*this, E, PD)) { 6948 return; 6949 } 6950 } 6951 6952 // Expect to find a single Decl. Skip anything more complicated. 6953 ValueDecl *D = nullptr; 6954 if (DeclRefExpr *R = dyn_cast<DeclRefExpr>(E)) { 6955 D = R->getDecl(); 6956 } else if (MemberExpr *M = dyn_cast<MemberExpr>(E)) { 6957 D = M->getMemberDecl(); 6958 } 6959 6960 // Weak Decls can be null. 6961 if (!D || D->isWeak()) 6962 return; 6963 6964 // Check for parameter decl with nonnull attribute 6965 if (const ParmVarDecl* PV = dyn_cast<ParmVarDecl>(D)) { 6966 if (getCurFunction() && !getCurFunction()->ModifiedNonNullParams.count(PV)) 6967 if (const FunctionDecl* FD = dyn_cast<FunctionDecl>(PV->getDeclContext())) { 6968 unsigned NumArgs = FD->getNumParams(); 6969 llvm::SmallBitVector AttrNonNull(NumArgs); 6970 for (const auto *NonNull : FD->specific_attrs<NonNullAttr>()) { 6971 if (!NonNull->args_size()) { 6972 AttrNonNull.set(0, NumArgs); 6973 break; 6974 } 6975 for (unsigned Val : NonNull->args()) { 6976 if (Val >= NumArgs) 6977 continue; 6978 AttrNonNull.set(Val); 6979 } 6980 } 6981 if (!AttrNonNull.empty()) 6982 for (unsigned i = 0; i < NumArgs; ++i) 6983 if (FD->getParamDecl(i) == PV && 6984 (AttrNonNull[i] || PV->hasAttr<NonNullAttr>())) { 6985 std::string Str; 6986 llvm::raw_string_ostream S(Str); 6987 E->printPretty(S, nullptr, getPrintingPolicy()); 6988 unsigned DiagID = IsCompare ? diag::warn_nonnull_parameter_compare 6989 : diag::warn_cast_nonnull_to_bool; 6990 Diag(E->getExprLoc(), DiagID) << S.str() << E->getSourceRange() 6991 << Range << IsEqual; 6992 return; 6993 } 6994 } 6995 } 6996 6997 QualType T = D->getType(); 6998 const bool IsArray = T->isArrayType(); 6999 const bool IsFunction = T->isFunctionType(); 7000 7001 // Address of function is used to silence the function warning. 7002 if (IsAddressOf && IsFunction) { 7003 return; 7004 } 7005 7006 // Found nothing. 7007 if (!IsAddressOf && !IsFunction && !IsArray) 7008 return; 7009 7010 // Pretty print the expression for the diagnostic. 7011 std::string Str; 7012 llvm::raw_string_ostream S(Str); 7013 E->printPretty(S, nullptr, getPrintingPolicy()); 7014 7015 unsigned DiagID = IsCompare ? diag::warn_null_pointer_compare 7016 : diag::warn_impcast_pointer_to_bool; 7017 unsigned DiagType; 7018 if (IsAddressOf) 7019 DiagType = AddressOf; 7020 else if (IsFunction) 7021 DiagType = FunctionPointer; 7022 else if (IsArray) 7023 DiagType = ArrayPointer; 7024 else 7025 llvm_unreachable("Could not determine diagnostic."); 7026 Diag(E->getExprLoc(), DiagID) << DiagType << S.str() << E->getSourceRange() 7027 << Range << IsEqual; 7028 7029 if (!IsFunction) 7030 return; 7031 7032 // Suggest '&' to silence the function warning. 7033 Diag(E->getExprLoc(), diag::note_function_warning_silence) 7034 << FixItHint::CreateInsertion(E->getLocStart(), "&"); 7035 7036 // Check to see if '()' fixit should be emitted. 7037 QualType ReturnType; 7038 UnresolvedSet<4> NonTemplateOverloads; 7039 tryExprAsCall(*E, ReturnType, NonTemplateOverloads); 7040 if (ReturnType.isNull()) 7041 return; 7042 7043 if (IsCompare) { 7044 // There are two cases here. If there is null constant, the only suggest 7045 // for a pointer return type. If the null is 0, then suggest if the return 7046 // type is a pointer or an integer type. 7047 if (!ReturnType->isPointerType()) { 7048 if (NullKind == Expr::NPCK_ZeroExpression || 7049 NullKind == Expr::NPCK_ZeroLiteral) { 7050 if (!ReturnType->isIntegerType()) 7051 return; 7052 } else { 7053 return; 7054 } 7055 } 7056 } else { // !IsCompare 7057 // For function to bool, only suggest if the function pointer has bool 7058 // return type. 7059 if (!ReturnType->isSpecificBuiltinType(BuiltinType::Bool)) 7060 return; 7061 } 7062 Diag(E->getExprLoc(), diag::note_function_to_function_call) 7063 << FixItHint::CreateInsertion(getLocForEndOfToken(E->getLocEnd()), "()"); 7064 } 7065 7066 7067 /// Diagnoses "dangerous" implicit conversions within the given 7068 /// expression (which is a full expression). Implements -Wconversion 7069 /// and -Wsign-compare. 7070 /// 7071 /// \param CC the "context" location of the implicit conversion, i.e. 7072 /// the most location of the syntactic entity requiring the implicit 7073 /// conversion 7074 void Sema::CheckImplicitConversions(Expr *E, SourceLocation CC) { 7075 // Don't diagnose in unevaluated contexts. 7076 if (isUnevaluatedContext()) 7077 return; 7078 7079 // Don't diagnose for value- or type-dependent expressions. 7080 if (E->isTypeDependent() || E->isValueDependent()) 7081 return; 7082 7083 // Check for array bounds violations in cases where the check isn't triggered 7084 // elsewhere for other Expr types (like BinaryOperators), e.g. when an 7085 // ArraySubscriptExpr is on the RHS of a variable initialization. 7086 CheckArrayAccess(E); 7087 7088 // This is not the right CC for (e.g.) a variable initialization. 7089 AnalyzeImplicitConversions(*this, E, CC); 7090 } 7091 7092 /// CheckBoolLikeConversion - Check conversion of given expression to boolean. 7093 /// Input argument E is a logical expression. 7094 void Sema::CheckBoolLikeConversion(Expr *E, SourceLocation CC) { 7095 ::CheckBoolLikeConversion(*this, E, CC); 7096 } 7097 7098 /// Diagnose when expression is an integer constant expression and its evaluation 7099 /// results in integer overflow 7100 void Sema::CheckForIntOverflow (Expr *E) { 7101 if (isa<BinaryOperator>(E->IgnoreParenCasts())) 7102 E->IgnoreParenCasts()->EvaluateForOverflow(Context); 7103 } 7104 7105 namespace { 7106 /// \brief Visitor for expressions which looks for unsequenced operations on the 7107 /// same object. 7108 class SequenceChecker : public EvaluatedExprVisitor<SequenceChecker> { 7109 typedef EvaluatedExprVisitor<SequenceChecker> Base; 7110 7111 /// \brief A tree of sequenced regions within an expression. Two regions are 7112 /// unsequenced if one is an ancestor or a descendent of the other. When we 7113 /// finish processing an expression with sequencing, such as a comma 7114 /// expression, we fold its tree nodes into its parent, since they are 7115 /// unsequenced with respect to nodes we will visit later. 7116 class SequenceTree { 7117 struct Value { 7118 explicit Value(unsigned Parent) : Parent(Parent), Merged(false) {} 7119 unsigned Parent : 31; 7120 bool Merged : 1; 7121 }; 7122 SmallVector<Value, 8> Values; 7123 7124 public: 7125 /// \brief A region within an expression which may be sequenced with respect 7126 /// to some other region. 7127 class Seq { 7128 explicit Seq(unsigned N) : Index(N) {} 7129 unsigned Index; 7130 friend class SequenceTree; 7131 public: 7132 Seq() : Index(0) {} 7133 }; 7134 7135 SequenceTree() { Values.push_back(Value(0)); } 7136 Seq root() const { return Seq(0); } 7137 7138 /// \brief Create a new sequence of operations, which is an unsequenced 7139 /// subset of \p Parent. This sequence of operations is sequenced with 7140 /// respect to other children of \p Parent. 7141 Seq allocate(Seq Parent) { 7142 Values.push_back(Value(Parent.Index)); 7143 return Seq(Values.size() - 1); 7144 } 7145 7146 /// \brief Merge a sequence of operations into its parent. 7147 void merge(Seq S) { 7148 Values[S.Index].Merged = true; 7149 } 7150 7151 /// \brief Determine whether two operations are unsequenced. This operation 7152 /// is asymmetric: \p Cur should be the more recent sequence, and \p Old 7153 /// should have been merged into its parent as appropriate. 7154 bool isUnsequenced(Seq Cur, Seq Old) { 7155 unsigned C = representative(Cur.Index); 7156 unsigned Target = representative(Old.Index); 7157 while (C >= Target) { 7158 if (C == Target) 7159 return true; 7160 C = Values[C].Parent; 7161 } 7162 return false; 7163 } 7164 7165 private: 7166 /// \brief Pick a representative for a sequence. 7167 unsigned representative(unsigned K) { 7168 if (Values[K].Merged) 7169 // Perform path compression as we go. 7170 return Values[K].Parent = representative(Values[K].Parent); 7171 return K; 7172 } 7173 }; 7174 7175 /// An object for which we can track unsequenced uses. 7176 typedef NamedDecl *Object; 7177 7178 /// Different flavors of object usage which we track. We only track the 7179 /// least-sequenced usage of each kind. 7180 enum UsageKind { 7181 /// A read of an object. Multiple unsequenced reads are OK. 7182 UK_Use, 7183 /// A modification of an object which is sequenced before the value 7184 /// computation of the expression, such as ++n in C++. 7185 UK_ModAsValue, 7186 /// A modification of an object which is not sequenced before the value 7187 /// computation of the expression, such as n++. 7188 UK_ModAsSideEffect, 7189 7190 UK_Count = UK_ModAsSideEffect + 1 7191 }; 7192 7193 struct Usage { 7194 Usage() : Use(nullptr), Seq() {} 7195 Expr *Use; 7196 SequenceTree::Seq Seq; 7197 }; 7198 7199 struct UsageInfo { 7200 UsageInfo() : Diagnosed(false) {} 7201 Usage Uses[UK_Count]; 7202 /// Have we issued a diagnostic for this variable already? 7203 bool Diagnosed; 7204 }; 7205 typedef llvm::SmallDenseMap<Object, UsageInfo, 16> UsageInfoMap; 7206 7207 Sema &SemaRef; 7208 /// Sequenced regions within the expression. 7209 SequenceTree Tree; 7210 /// Declaration modifications and references which we have seen. 7211 UsageInfoMap UsageMap; 7212 /// The region we are currently within. 7213 SequenceTree::Seq Region; 7214 /// Filled in with declarations which were modified as a side-effect 7215 /// (that is, post-increment operations). 7216 SmallVectorImpl<std::pair<Object, Usage> > *ModAsSideEffect; 7217 /// Expressions to check later. We defer checking these to reduce 7218 /// stack usage. 7219 SmallVectorImpl<Expr *> &WorkList; 7220 7221 /// RAII object wrapping the visitation of a sequenced subexpression of an 7222 /// expression. At the end of this process, the side-effects of the evaluation 7223 /// become sequenced with respect to the value computation of the result, so 7224 /// we downgrade any UK_ModAsSideEffect within the evaluation to 7225 /// UK_ModAsValue. 7226 struct SequencedSubexpression { 7227 SequencedSubexpression(SequenceChecker &Self) 7228 : Self(Self), OldModAsSideEffect(Self.ModAsSideEffect) { 7229 Self.ModAsSideEffect = &ModAsSideEffect; 7230 } 7231 ~SequencedSubexpression() { 7232 for (auto MI = ModAsSideEffect.rbegin(), ME = ModAsSideEffect.rend(); 7233 MI != ME; ++MI) { 7234 UsageInfo &U = Self.UsageMap[MI->first]; 7235 auto &SideEffectUsage = U.Uses[UK_ModAsSideEffect]; 7236 Self.addUsage(U, MI->first, SideEffectUsage.Use, UK_ModAsValue); 7237 SideEffectUsage = MI->second; 7238 } 7239 Self.ModAsSideEffect = OldModAsSideEffect; 7240 } 7241 7242 SequenceChecker &Self; 7243 SmallVector<std::pair<Object, Usage>, 4> ModAsSideEffect; 7244 SmallVectorImpl<std::pair<Object, Usage> > *OldModAsSideEffect; 7245 }; 7246 7247 /// RAII object wrapping the visitation of a subexpression which we might 7248 /// choose to evaluate as a constant. If any subexpression is evaluated and 7249 /// found to be non-constant, this allows us to suppress the evaluation of 7250 /// the outer expression. 7251 class EvaluationTracker { 7252 public: 7253 EvaluationTracker(SequenceChecker &Self) 7254 : Self(Self), Prev(Self.EvalTracker), EvalOK(true) { 7255 Self.EvalTracker = this; 7256 } 7257 ~EvaluationTracker() { 7258 Self.EvalTracker = Prev; 7259 if (Prev) 7260 Prev->EvalOK &= EvalOK; 7261 } 7262 7263 bool evaluate(const Expr *E, bool &Result) { 7264 if (!EvalOK || E->isValueDependent()) 7265 return false; 7266 EvalOK = E->EvaluateAsBooleanCondition(Result, Self.SemaRef.Context); 7267 return EvalOK; 7268 } 7269 7270 private: 7271 SequenceChecker &Self; 7272 EvaluationTracker *Prev; 7273 bool EvalOK; 7274 } *EvalTracker; 7275 7276 /// \brief Find the object which is produced by the specified expression, 7277 /// if any. 7278 Object getObject(Expr *E, bool Mod) const { 7279 E = E->IgnoreParenCasts(); 7280 if (UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) { 7281 if (Mod && (UO->getOpcode() == UO_PreInc || UO->getOpcode() == UO_PreDec)) 7282 return getObject(UO->getSubExpr(), Mod); 7283 } else if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) { 7284 if (BO->getOpcode() == BO_Comma) 7285 return getObject(BO->getRHS(), Mod); 7286 if (Mod && BO->isAssignmentOp()) 7287 return getObject(BO->getLHS(), Mod); 7288 } else if (MemberExpr *ME = dyn_cast<MemberExpr>(E)) { 7289 // FIXME: Check for more interesting cases, like "x.n = ++x.n". 7290 if (isa<CXXThisExpr>(ME->getBase()->IgnoreParenCasts())) 7291 return ME->getMemberDecl(); 7292 } else if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) 7293 // FIXME: If this is a reference, map through to its value. 7294 return DRE->getDecl(); 7295 return nullptr; 7296 } 7297 7298 /// \brief Note that an object was modified or used by an expression. 7299 void addUsage(UsageInfo &UI, Object O, Expr *Ref, UsageKind UK) { 7300 Usage &U = UI.Uses[UK]; 7301 if (!U.Use || !Tree.isUnsequenced(Region, U.Seq)) { 7302 if (UK == UK_ModAsSideEffect && ModAsSideEffect) 7303 ModAsSideEffect->push_back(std::make_pair(O, U)); 7304 U.Use = Ref; 7305 U.Seq = Region; 7306 } 7307 } 7308 /// \brief Check whether a modification or use conflicts with a prior usage. 7309 void checkUsage(Object O, UsageInfo &UI, Expr *Ref, UsageKind OtherKind, 7310 bool IsModMod) { 7311 if (UI.Diagnosed) 7312 return; 7313 7314 const Usage &U = UI.Uses[OtherKind]; 7315 if (!U.Use || !Tree.isUnsequenced(Region, U.Seq)) 7316 return; 7317 7318 Expr *Mod = U.Use; 7319 Expr *ModOrUse = Ref; 7320 if (OtherKind == UK_Use) 7321 std::swap(Mod, ModOrUse); 7322 7323 SemaRef.Diag(Mod->getExprLoc(), 7324 IsModMod ? diag::warn_unsequenced_mod_mod 7325 : diag::warn_unsequenced_mod_use) 7326 << O << SourceRange(ModOrUse->getExprLoc()); 7327 UI.Diagnosed = true; 7328 } 7329 7330 void notePreUse(Object O, Expr *Use) { 7331 UsageInfo &U = UsageMap[O]; 7332 // Uses conflict with other modifications. 7333 checkUsage(O, U, Use, UK_ModAsValue, false); 7334 } 7335 void notePostUse(Object O, Expr *Use) { 7336 UsageInfo &U = UsageMap[O]; 7337 checkUsage(O, U, Use, UK_ModAsSideEffect, false); 7338 addUsage(U, O, Use, UK_Use); 7339 } 7340 7341 void notePreMod(Object O, Expr *Mod) { 7342 UsageInfo &U = UsageMap[O]; 7343 // Modifications conflict with other modifications and with uses. 7344 checkUsage(O, U, Mod, UK_ModAsValue, true); 7345 checkUsage(O, U, Mod, UK_Use, false); 7346 } 7347 void notePostMod(Object O, Expr *Use, UsageKind UK) { 7348 UsageInfo &U = UsageMap[O]; 7349 checkUsage(O, U, Use, UK_ModAsSideEffect, true); 7350 addUsage(U, O, Use, UK); 7351 } 7352 7353 public: 7354 SequenceChecker(Sema &S, Expr *E, SmallVectorImpl<Expr *> &WorkList) 7355 : Base(S.Context), SemaRef(S), Region(Tree.root()), 7356 ModAsSideEffect(nullptr), WorkList(WorkList), EvalTracker(nullptr) { 7357 Visit(E); 7358 } 7359 7360 void VisitStmt(Stmt *S) { 7361 // Skip all statements which aren't expressions for now. 7362 } 7363 7364 void VisitExpr(Expr *E) { 7365 // By default, just recurse to evaluated subexpressions. 7366 Base::VisitStmt(E); 7367 } 7368 7369 void VisitCastExpr(CastExpr *E) { 7370 Object O = Object(); 7371 if (E->getCastKind() == CK_LValueToRValue) 7372 O = getObject(E->getSubExpr(), false); 7373 7374 if (O) 7375 notePreUse(O, E); 7376 VisitExpr(E); 7377 if (O) 7378 notePostUse(O, E); 7379 } 7380 7381 void VisitBinComma(BinaryOperator *BO) { 7382 // C++11 [expr.comma]p1: 7383 // Every value computation and side effect associated with the left 7384 // expression is sequenced before every value computation and side 7385 // effect associated with the right expression. 7386 SequenceTree::Seq LHS = Tree.allocate(Region); 7387 SequenceTree::Seq RHS = Tree.allocate(Region); 7388 SequenceTree::Seq OldRegion = Region; 7389 7390 { 7391 SequencedSubexpression SeqLHS(*this); 7392 Region = LHS; 7393 Visit(BO->getLHS()); 7394 } 7395 7396 Region = RHS; 7397 Visit(BO->getRHS()); 7398 7399 Region = OldRegion; 7400 7401 // Forget that LHS and RHS are sequenced. They are both unsequenced 7402 // with respect to other stuff. 7403 Tree.merge(LHS); 7404 Tree.merge(RHS); 7405 } 7406 7407 void VisitBinAssign(BinaryOperator *BO) { 7408 // The modification is sequenced after the value computation of the LHS 7409 // and RHS, so check it before inspecting the operands and update the 7410 // map afterwards. 7411 Object O = getObject(BO->getLHS(), true); 7412 if (!O) 7413 return VisitExpr(BO); 7414 7415 notePreMod(O, BO); 7416 7417 // C++11 [expr.ass]p7: 7418 // E1 op= E2 is equivalent to E1 = E1 op E2, except that E1 is evaluated 7419 // only once. 7420 // 7421 // Therefore, for a compound assignment operator, O is considered used 7422 // everywhere except within the evaluation of E1 itself. 7423 if (isa<CompoundAssignOperator>(BO)) 7424 notePreUse(O, BO); 7425 7426 Visit(BO->getLHS()); 7427 7428 if (isa<CompoundAssignOperator>(BO)) 7429 notePostUse(O, BO); 7430 7431 Visit(BO->getRHS()); 7432 7433 // C++11 [expr.ass]p1: 7434 // the assignment is sequenced [...] before the value computation of the 7435 // assignment expression. 7436 // C11 6.5.16/3 has no such rule. 7437 notePostMod(O, BO, SemaRef.getLangOpts().CPlusPlus ? UK_ModAsValue 7438 : UK_ModAsSideEffect); 7439 } 7440 void VisitCompoundAssignOperator(CompoundAssignOperator *CAO) { 7441 VisitBinAssign(CAO); 7442 } 7443 7444 void VisitUnaryPreInc(UnaryOperator *UO) { VisitUnaryPreIncDec(UO); } 7445 void VisitUnaryPreDec(UnaryOperator *UO) { VisitUnaryPreIncDec(UO); } 7446 void VisitUnaryPreIncDec(UnaryOperator *UO) { 7447 Object O = getObject(UO->getSubExpr(), true); 7448 if (!O) 7449 return VisitExpr(UO); 7450 7451 notePreMod(O, UO); 7452 Visit(UO->getSubExpr()); 7453 // C++11 [expr.pre.incr]p1: 7454 // the expression ++x is equivalent to x+=1 7455 notePostMod(O, UO, SemaRef.getLangOpts().CPlusPlus ? UK_ModAsValue 7456 : UK_ModAsSideEffect); 7457 } 7458 7459 void VisitUnaryPostInc(UnaryOperator *UO) { VisitUnaryPostIncDec(UO); } 7460 void VisitUnaryPostDec(UnaryOperator *UO) { VisitUnaryPostIncDec(UO); } 7461 void VisitUnaryPostIncDec(UnaryOperator *UO) { 7462 Object O = getObject(UO->getSubExpr(), true); 7463 if (!O) 7464 return VisitExpr(UO); 7465 7466 notePreMod(O, UO); 7467 Visit(UO->getSubExpr()); 7468 notePostMod(O, UO, UK_ModAsSideEffect); 7469 } 7470 7471 /// Don't visit the RHS of '&&' or '||' if it might not be evaluated. 7472 void VisitBinLOr(BinaryOperator *BO) { 7473 // The side-effects of the LHS of an '&&' are sequenced before the 7474 // value computation of the RHS, and hence before the value computation 7475 // of the '&&' itself, unless the LHS evaluates to zero. We treat them 7476 // as if they were unconditionally sequenced. 7477 EvaluationTracker Eval(*this); 7478 { 7479 SequencedSubexpression Sequenced(*this); 7480 Visit(BO->getLHS()); 7481 } 7482 7483 bool Result; 7484 if (Eval.evaluate(BO->getLHS(), Result)) { 7485 if (!Result) 7486 Visit(BO->getRHS()); 7487 } else { 7488 // Check for unsequenced operations in the RHS, treating it as an 7489 // entirely separate evaluation. 7490 // 7491 // FIXME: If there are operations in the RHS which are unsequenced 7492 // with respect to operations outside the RHS, and those operations 7493 // are unconditionally evaluated, diagnose them. 7494 WorkList.push_back(BO->getRHS()); 7495 } 7496 } 7497 void VisitBinLAnd(BinaryOperator *BO) { 7498 EvaluationTracker Eval(*this); 7499 { 7500 SequencedSubexpression Sequenced(*this); 7501 Visit(BO->getLHS()); 7502 } 7503 7504 bool Result; 7505 if (Eval.evaluate(BO->getLHS(), Result)) { 7506 if (Result) 7507 Visit(BO->getRHS()); 7508 } else { 7509 WorkList.push_back(BO->getRHS()); 7510 } 7511 } 7512 7513 // Only visit the condition, unless we can be sure which subexpression will 7514 // be chosen. 7515 void VisitAbstractConditionalOperator(AbstractConditionalOperator *CO) { 7516 EvaluationTracker Eval(*this); 7517 { 7518 SequencedSubexpression Sequenced(*this); 7519 Visit(CO->getCond()); 7520 } 7521 7522 bool Result; 7523 if (Eval.evaluate(CO->getCond(), Result)) 7524 Visit(Result ? CO->getTrueExpr() : CO->getFalseExpr()); 7525 else { 7526 WorkList.push_back(CO->getTrueExpr()); 7527 WorkList.push_back(CO->getFalseExpr()); 7528 } 7529 } 7530 7531 void VisitCallExpr(CallExpr *CE) { 7532 // C++11 [intro.execution]p15: 7533 // When calling a function [...], every value computation and side effect 7534 // associated with any argument expression, or with the postfix expression 7535 // designating the called function, is sequenced before execution of every 7536 // expression or statement in the body of the function [and thus before 7537 // the value computation of its result]. 7538 SequencedSubexpression Sequenced(*this); 7539 Base::VisitCallExpr(CE); 7540 7541 // FIXME: CXXNewExpr and CXXDeleteExpr implicitly call functions. 7542 } 7543 7544 void VisitCXXConstructExpr(CXXConstructExpr *CCE) { 7545 // This is a call, so all subexpressions are sequenced before the result. 7546 SequencedSubexpression Sequenced(*this); 7547 7548 if (!CCE->isListInitialization()) 7549 return VisitExpr(CCE); 7550 7551 // In C++11, list initializations are sequenced. 7552 SmallVector<SequenceTree::Seq, 32> Elts; 7553 SequenceTree::Seq Parent = Region; 7554 for (CXXConstructExpr::arg_iterator I = CCE->arg_begin(), 7555 E = CCE->arg_end(); 7556 I != E; ++I) { 7557 Region = Tree.allocate(Parent); 7558 Elts.push_back(Region); 7559 Visit(*I); 7560 } 7561 7562 // Forget that the initializers are sequenced. 7563 Region = Parent; 7564 for (unsigned I = 0; I < Elts.size(); ++I) 7565 Tree.merge(Elts[I]); 7566 } 7567 7568 void VisitInitListExpr(InitListExpr *ILE) { 7569 if (!SemaRef.getLangOpts().CPlusPlus11) 7570 return VisitExpr(ILE); 7571 7572 // In C++11, list initializations are sequenced. 7573 SmallVector<SequenceTree::Seq, 32> Elts; 7574 SequenceTree::Seq Parent = Region; 7575 for (unsigned I = 0; I < ILE->getNumInits(); ++I) { 7576 Expr *E = ILE->getInit(I); 7577 if (!E) continue; 7578 Region = Tree.allocate(Parent); 7579 Elts.push_back(Region); 7580 Visit(E); 7581 } 7582 7583 // Forget that the initializers are sequenced. 7584 Region = Parent; 7585 for (unsigned I = 0; I < Elts.size(); ++I) 7586 Tree.merge(Elts[I]); 7587 } 7588 }; 7589 } 7590 7591 void Sema::CheckUnsequencedOperations(Expr *E) { 7592 SmallVector<Expr *, 8> WorkList; 7593 WorkList.push_back(E); 7594 while (!WorkList.empty()) { 7595 Expr *Item = WorkList.pop_back_val(); 7596 SequenceChecker(*this, Item, WorkList); 7597 } 7598 } 7599 7600 void Sema::CheckCompletedExpr(Expr *E, SourceLocation CheckLoc, 7601 bool IsConstexpr) { 7602 CheckImplicitConversions(E, CheckLoc); 7603 CheckUnsequencedOperations(E); 7604 if (!IsConstexpr && !E->isValueDependent()) 7605 CheckForIntOverflow(E); 7606 } 7607 7608 void Sema::CheckBitFieldInitialization(SourceLocation InitLoc, 7609 FieldDecl *BitField, 7610 Expr *Init) { 7611 (void) AnalyzeBitFieldAssignment(*this, BitField, Init, InitLoc); 7612 } 7613 7614 /// CheckParmsForFunctionDef - Check that the parameters of the given 7615 /// function are appropriate for the definition of a function. This 7616 /// takes care of any checks that cannot be performed on the 7617 /// declaration itself, e.g., that the types of each of the function 7618 /// parameters are complete. 7619 bool Sema::CheckParmsForFunctionDef(ParmVarDecl *const *P, 7620 ParmVarDecl *const *PEnd, 7621 bool CheckParameterNames) { 7622 bool HasInvalidParm = false; 7623 for (; P != PEnd; ++P) { 7624 ParmVarDecl *Param = *P; 7625 7626 // C99 6.7.5.3p4: the parameters in a parameter type list in a 7627 // function declarator that is part of a function definition of 7628 // that function shall not have incomplete type. 7629 // 7630 // This is also C++ [dcl.fct]p6. 7631 if (!Param->isInvalidDecl() && 7632 RequireCompleteType(Param->getLocation(), Param->getType(), 7633 diag::err_typecheck_decl_incomplete_type)) { 7634 Param->setInvalidDecl(); 7635 HasInvalidParm = true; 7636 } 7637 7638 // C99 6.9.1p5: If the declarator includes a parameter type list, the 7639 // declaration of each parameter shall include an identifier. 7640 if (CheckParameterNames && 7641 Param->getIdentifier() == nullptr && 7642 !Param->isImplicit() && 7643 !getLangOpts().CPlusPlus) 7644 Diag(Param->getLocation(), diag::err_parameter_name_omitted); 7645 7646 // C99 6.7.5.3p12: 7647 // If the function declarator is not part of a definition of that 7648 // function, parameters may have incomplete type and may use the [*] 7649 // notation in their sequences of declarator specifiers to specify 7650 // variable length array types. 7651 QualType PType = Param->getOriginalType(); 7652 while (const ArrayType *AT = Context.getAsArrayType(PType)) { 7653 if (AT->getSizeModifier() == ArrayType::Star) { 7654 // FIXME: This diagnostic should point the '[*]' if source-location 7655 // information is added for it. 7656 Diag(Param->getLocation(), diag::err_array_star_in_function_definition); 7657 break; 7658 } 7659 PType= AT->getElementType(); 7660 } 7661 7662 // MSVC destroys objects passed by value in the callee. Therefore a 7663 // function definition which takes such a parameter must be able to call the 7664 // object's destructor. However, we don't perform any direct access check 7665 // on the dtor. 7666 if (getLangOpts().CPlusPlus && Context.getTargetInfo() 7667 .getCXXABI() 7668 .areArgsDestroyedLeftToRightInCallee()) { 7669 if (!Param->isInvalidDecl()) { 7670 if (const RecordType *RT = Param->getType()->getAs<RecordType>()) { 7671 CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(RT->getDecl()); 7672 if (!ClassDecl->isInvalidDecl() && 7673 !ClassDecl->hasIrrelevantDestructor() && 7674 !ClassDecl->isDependentContext()) { 7675 CXXDestructorDecl *Destructor = LookupDestructor(ClassDecl); 7676 MarkFunctionReferenced(Param->getLocation(), Destructor); 7677 DiagnoseUseOfDecl(Destructor, Param->getLocation()); 7678 } 7679 } 7680 } 7681 } 7682 } 7683 7684 return HasInvalidParm; 7685 } 7686 7687 /// CheckCastAlign - Implements -Wcast-align, which warns when a 7688 /// pointer cast increases the alignment requirements. 7689 void Sema::CheckCastAlign(Expr *Op, QualType T, SourceRange TRange) { 7690 // This is actually a lot of work to potentially be doing on every 7691 // cast; don't do it if we're ignoring -Wcast_align (as is the default). 7692 if (getDiagnostics().isIgnored(diag::warn_cast_align, TRange.getBegin())) 7693 return; 7694 7695 // Ignore dependent types. 7696 if (T->isDependentType() || Op->getType()->isDependentType()) 7697 return; 7698 7699 // Require that the destination be a pointer type. 7700 const PointerType *DestPtr = T->getAs<PointerType>(); 7701 if (!DestPtr) return; 7702 7703 // If the destination has alignment 1, we're done. 7704 QualType DestPointee = DestPtr->getPointeeType(); 7705 if (DestPointee->isIncompleteType()) return; 7706 CharUnits DestAlign = Context.getTypeAlignInChars(DestPointee); 7707 if (DestAlign.isOne()) return; 7708 7709 // Require that the source be a pointer type. 7710 const PointerType *SrcPtr = Op->getType()->getAs<PointerType>(); 7711 if (!SrcPtr) return; 7712 QualType SrcPointee = SrcPtr->getPointeeType(); 7713 7714 // Whitelist casts from cv void*. We already implicitly 7715 // whitelisted casts to cv void*, since they have alignment 1. 7716 // Also whitelist casts involving incomplete types, which implicitly 7717 // includes 'void'. 7718 if (SrcPointee->isIncompleteType()) return; 7719 7720 CharUnits SrcAlign = Context.getTypeAlignInChars(SrcPointee); 7721 if (SrcAlign >= DestAlign) return; 7722 7723 Diag(TRange.getBegin(), diag::warn_cast_align) 7724 << Op->getType() << T 7725 << static_cast<unsigned>(SrcAlign.getQuantity()) 7726 << static_cast<unsigned>(DestAlign.getQuantity()) 7727 << TRange << Op->getSourceRange(); 7728 } 7729 7730 static const Type* getElementType(const Expr *BaseExpr) { 7731 const Type* EltType = BaseExpr->getType().getTypePtr(); 7732 if (EltType->isAnyPointerType()) 7733 return EltType->getPointeeType().getTypePtr(); 7734 else if (EltType->isArrayType()) 7735 return EltType->getBaseElementTypeUnsafe(); 7736 return EltType; 7737 } 7738 7739 /// \brief Check whether this array fits the idiom of a size-one tail padded 7740 /// array member of a struct. 7741 /// 7742 /// We avoid emitting out-of-bounds access warnings for such arrays as they are 7743 /// commonly used to emulate flexible arrays in C89 code. 7744 static bool IsTailPaddedMemberArray(Sema &S, llvm::APInt Size, 7745 const NamedDecl *ND) { 7746 if (Size != 1 || !ND) return false; 7747 7748 const FieldDecl *FD = dyn_cast<FieldDecl>(ND); 7749 if (!FD) return false; 7750 7751 // Don't consider sizes resulting from macro expansions or template argument 7752 // substitution to form C89 tail-padded arrays. 7753 7754 TypeSourceInfo *TInfo = FD->getTypeSourceInfo(); 7755 while (TInfo) { 7756 TypeLoc TL = TInfo->getTypeLoc(); 7757 // Look through typedefs. 7758 if (TypedefTypeLoc TTL = TL.getAs<TypedefTypeLoc>()) { 7759 const TypedefNameDecl *TDL = TTL.getTypedefNameDecl(); 7760 TInfo = TDL->getTypeSourceInfo(); 7761 continue; 7762 } 7763 if (ConstantArrayTypeLoc CTL = TL.getAs<ConstantArrayTypeLoc>()) { 7764 const Expr *SizeExpr = dyn_cast<IntegerLiteral>(CTL.getSizeExpr()); 7765 if (!SizeExpr || SizeExpr->getExprLoc().isMacroID()) 7766 return false; 7767 } 7768 break; 7769 } 7770 7771 const RecordDecl *RD = dyn_cast<RecordDecl>(FD->getDeclContext()); 7772 if (!RD) return false; 7773 if (RD->isUnion()) return false; 7774 if (const CXXRecordDecl *CRD = dyn_cast<CXXRecordDecl>(RD)) { 7775 if (!CRD->isStandardLayout()) return false; 7776 } 7777 7778 // See if this is the last field decl in the record. 7779 const Decl *D = FD; 7780 while ((D = D->getNextDeclInContext())) 7781 if (isa<FieldDecl>(D)) 7782 return false; 7783 return true; 7784 } 7785 7786 void Sema::CheckArrayAccess(const Expr *BaseExpr, const Expr *IndexExpr, 7787 const ArraySubscriptExpr *ASE, 7788 bool AllowOnePastEnd, bool IndexNegated) { 7789 IndexExpr = IndexExpr->IgnoreParenImpCasts(); 7790 if (IndexExpr->isValueDependent()) 7791 return; 7792 7793 const Type *EffectiveType = getElementType(BaseExpr); 7794 BaseExpr = BaseExpr->IgnoreParenCasts(); 7795 const ConstantArrayType *ArrayTy = 7796 Context.getAsConstantArrayType(BaseExpr->getType()); 7797 if (!ArrayTy) 7798 return; 7799 7800 llvm::APSInt index; 7801 if (!IndexExpr->EvaluateAsInt(index, Context)) 7802 return; 7803 if (IndexNegated) 7804 index = -index; 7805 7806 const NamedDecl *ND = nullptr; 7807 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(BaseExpr)) 7808 ND = dyn_cast<NamedDecl>(DRE->getDecl()); 7809 if (const MemberExpr *ME = dyn_cast<MemberExpr>(BaseExpr)) 7810 ND = dyn_cast<NamedDecl>(ME->getMemberDecl()); 7811 7812 if (index.isUnsigned() || !index.isNegative()) { 7813 llvm::APInt size = ArrayTy->getSize(); 7814 if (!size.isStrictlyPositive()) 7815 return; 7816 7817 const Type* BaseType = getElementType(BaseExpr); 7818 if (BaseType != EffectiveType) { 7819 // Make sure we're comparing apples to apples when comparing index to size 7820 uint64_t ptrarith_typesize = Context.getTypeSize(EffectiveType); 7821 uint64_t array_typesize = Context.getTypeSize(BaseType); 7822 // Handle ptrarith_typesize being zero, such as when casting to void* 7823 if (!ptrarith_typesize) ptrarith_typesize = 1; 7824 if (ptrarith_typesize != array_typesize) { 7825 // There's a cast to a different size type involved 7826 uint64_t ratio = array_typesize / ptrarith_typesize; 7827 // TODO: Be smarter about handling cases where array_typesize is not a 7828 // multiple of ptrarith_typesize 7829 if (ptrarith_typesize * ratio == array_typesize) 7830 size *= llvm::APInt(size.getBitWidth(), ratio); 7831 } 7832 } 7833 7834 if (size.getBitWidth() > index.getBitWidth()) 7835 index = index.zext(size.getBitWidth()); 7836 else if (size.getBitWidth() < index.getBitWidth()) 7837 size = size.zext(index.getBitWidth()); 7838 7839 // For array subscripting the index must be less than size, but for pointer 7840 // arithmetic also allow the index (offset) to be equal to size since 7841 // computing the next address after the end of the array is legal and 7842 // commonly done e.g. in C++ iterators and range-based for loops. 7843 if (AllowOnePastEnd ? index.ule(size) : index.ult(size)) 7844 return; 7845 7846 // Also don't warn for arrays of size 1 which are members of some 7847 // structure. These are often used to approximate flexible arrays in C89 7848 // code. 7849 if (IsTailPaddedMemberArray(*this, size, ND)) 7850 return; 7851 7852 // Suppress the warning if the subscript expression (as identified by the 7853 // ']' location) and the index expression are both from macro expansions 7854 // within a system header. 7855 if (ASE) { 7856 SourceLocation RBracketLoc = SourceMgr.getSpellingLoc( 7857 ASE->getRBracketLoc()); 7858 if (SourceMgr.isInSystemHeader(RBracketLoc)) { 7859 SourceLocation IndexLoc = SourceMgr.getSpellingLoc( 7860 IndexExpr->getLocStart()); 7861 if (SourceMgr.isWrittenInSameFile(RBracketLoc, IndexLoc)) 7862 return; 7863 } 7864 } 7865 7866 unsigned DiagID = diag::warn_ptr_arith_exceeds_bounds; 7867 if (ASE) 7868 DiagID = diag::warn_array_index_exceeds_bounds; 7869 7870 DiagRuntimeBehavior(BaseExpr->getLocStart(), BaseExpr, 7871 PDiag(DiagID) << index.toString(10, true) 7872 << size.toString(10, true) 7873 << (unsigned)size.getLimitedValue(~0U) 7874 << IndexExpr->getSourceRange()); 7875 } else { 7876 unsigned DiagID = diag::warn_array_index_precedes_bounds; 7877 if (!ASE) { 7878 DiagID = diag::warn_ptr_arith_precedes_bounds; 7879 if (index.isNegative()) index = -index; 7880 } 7881 7882 DiagRuntimeBehavior(BaseExpr->getLocStart(), BaseExpr, 7883 PDiag(DiagID) << index.toString(10, true) 7884 << IndexExpr->getSourceRange()); 7885 } 7886 7887 if (!ND) { 7888 // Try harder to find a NamedDecl to point at in the note. 7889 while (const ArraySubscriptExpr *ASE = 7890 dyn_cast<ArraySubscriptExpr>(BaseExpr)) 7891 BaseExpr = ASE->getBase()->IgnoreParenCasts(); 7892 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(BaseExpr)) 7893 ND = dyn_cast<NamedDecl>(DRE->getDecl()); 7894 if (const MemberExpr *ME = dyn_cast<MemberExpr>(BaseExpr)) 7895 ND = dyn_cast<NamedDecl>(ME->getMemberDecl()); 7896 } 7897 7898 if (ND) 7899 DiagRuntimeBehavior(ND->getLocStart(), BaseExpr, 7900 PDiag(diag::note_array_index_out_of_bounds) 7901 << ND->getDeclName()); 7902 } 7903 7904 void Sema::CheckArrayAccess(const Expr *expr) { 7905 int AllowOnePastEnd = 0; 7906 while (expr) { 7907 expr = expr->IgnoreParenImpCasts(); 7908 switch (expr->getStmtClass()) { 7909 case Stmt::ArraySubscriptExprClass: { 7910 const ArraySubscriptExpr *ASE = cast<ArraySubscriptExpr>(expr); 7911 CheckArrayAccess(ASE->getBase(), ASE->getIdx(), ASE, 7912 AllowOnePastEnd > 0); 7913 return; 7914 } 7915 case Stmt::UnaryOperatorClass: { 7916 // Only unwrap the * and & unary operators 7917 const UnaryOperator *UO = cast<UnaryOperator>(expr); 7918 expr = UO->getSubExpr(); 7919 switch (UO->getOpcode()) { 7920 case UO_AddrOf: 7921 AllowOnePastEnd++; 7922 break; 7923 case UO_Deref: 7924 AllowOnePastEnd--; 7925 break; 7926 default: 7927 return; 7928 } 7929 break; 7930 } 7931 case Stmt::ConditionalOperatorClass: { 7932 const ConditionalOperator *cond = cast<ConditionalOperator>(expr); 7933 if (const Expr *lhs = cond->getLHS()) 7934 CheckArrayAccess(lhs); 7935 if (const Expr *rhs = cond->getRHS()) 7936 CheckArrayAccess(rhs); 7937 return; 7938 } 7939 default: 7940 return; 7941 } 7942 } 7943 } 7944 7945 //===--- CHECK: Objective-C retain cycles ----------------------------------// 7946 7947 namespace { 7948 struct RetainCycleOwner { 7949 RetainCycleOwner() : Variable(nullptr), Indirect(false) {} 7950 VarDecl *Variable; 7951 SourceRange Range; 7952 SourceLocation Loc; 7953 bool Indirect; 7954 7955 void setLocsFrom(Expr *e) { 7956 Loc = e->getExprLoc(); 7957 Range = e->getSourceRange(); 7958 } 7959 }; 7960 } 7961 7962 /// Consider whether capturing the given variable can possibly lead to 7963 /// a retain cycle. 7964 static bool considerVariable(VarDecl *var, Expr *ref, RetainCycleOwner &owner) { 7965 // In ARC, it's captured strongly iff the variable has __strong 7966 // lifetime. In MRR, it's captured strongly if the variable is 7967 // __block and has an appropriate type. 7968 if (var->getType().getObjCLifetime() != Qualifiers::OCL_Strong) 7969 return false; 7970 7971 owner.Variable = var; 7972 if (ref) 7973 owner.setLocsFrom(ref); 7974 return true; 7975 } 7976 7977 static bool findRetainCycleOwner(Sema &S, Expr *e, RetainCycleOwner &owner) { 7978 while (true) { 7979 e = e->IgnoreParens(); 7980 if (CastExpr *cast = dyn_cast<CastExpr>(e)) { 7981 switch (cast->getCastKind()) { 7982 case CK_BitCast: 7983 case CK_LValueBitCast: 7984 case CK_LValueToRValue: 7985 case CK_ARCReclaimReturnedObject: 7986 e = cast->getSubExpr(); 7987 continue; 7988 7989 default: 7990 return false; 7991 } 7992 } 7993 7994 if (ObjCIvarRefExpr *ref = dyn_cast<ObjCIvarRefExpr>(e)) { 7995 ObjCIvarDecl *ivar = ref->getDecl(); 7996 if (ivar->getType().getObjCLifetime() != Qualifiers::OCL_Strong) 7997 return false; 7998 7999 // Try to find a retain cycle in the base. 8000 if (!findRetainCycleOwner(S, ref->getBase(), owner)) 8001 return false; 8002 8003 if (ref->isFreeIvar()) owner.setLocsFrom(ref); 8004 owner.Indirect = true; 8005 return true; 8006 } 8007 8008 if (DeclRefExpr *ref = dyn_cast<DeclRefExpr>(e)) { 8009 VarDecl *var = dyn_cast<VarDecl>(ref->getDecl()); 8010 if (!var) return false; 8011 return considerVariable(var, ref, owner); 8012 } 8013 8014 if (MemberExpr *member = dyn_cast<MemberExpr>(e)) { 8015 if (member->isArrow()) return false; 8016 8017 // Don't count this as an indirect ownership. 8018 e = member->getBase(); 8019 continue; 8020 } 8021 8022 if (PseudoObjectExpr *pseudo = dyn_cast<PseudoObjectExpr>(e)) { 8023 // Only pay attention to pseudo-objects on property references. 8024 ObjCPropertyRefExpr *pre 8025 = dyn_cast<ObjCPropertyRefExpr>(pseudo->getSyntacticForm() 8026 ->IgnoreParens()); 8027 if (!pre) return false; 8028 if (pre->isImplicitProperty()) return false; 8029 ObjCPropertyDecl *property = pre->getExplicitProperty(); 8030 if (!property->isRetaining() && 8031 !(property->getPropertyIvarDecl() && 8032 property->getPropertyIvarDecl()->getType() 8033 .getObjCLifetime() == Qualifiers::OCL_Strong)) 8034 return false; 8035 8036 owner.Indirect = true; 8037 if (pre->isSuperReceiver()) { 8038 owner.Variable = S.getCurMethodDecl()->getSelfDecl(); 8039 if (!owner.Variable) 8040 return false; 8041 owner.Loc = pre->getLocation(); 8042 owner.Range = pre->getSourceRange(); 8043 return true; 8044 } 8045 e = const_cast<Expr*>(cast<OpaqueValueExpr>(pre->getBase()) 8046 ->getSourceExpr()); 8047 continue; 8048 } 8049 8050 // Array ivars? 8051 8052 return false; 8053 } 8054 } 8055 8056 namespace { 8057 struct FindCaptureVisitor : EvaluatedExprVisitor<FindCaptureVisitor> { 8058 FindCaptureVisitor(ASTContext &Context, VarDecl *variable) 8059 : EvaluatedExprVisitor<FindCaptureVisitor>(Context), 8060 Context(Context), Variable(variable), Capturer(nullptr), 8061 VarWillBeReased(false) {} 8062 ASTContext &Context; 8063 VarDecl *Variable; 8064 Expr *Capturer; 8065 bool VarWillBeReased; 8066 8067 void VisitDeclRefExpr(DeclRefExpr *ref) { 8068 if (ref->getDecl() == Variable && !Capturer) 8069 Capturer = ref; 8070 } 8071 8072 void VisitObjCIvarRefExpr(ObjCIvarRefExpr *ref) { 8073 if (Capturer) return; 8074 Visit(ref->getBase()); 8075 if (Capturer && ref->isFreeIvar()) 8076 Capturer = ref; 8077 } 8078 8079 void VisitBlockExpr(BlockExpr *block) { 8080 // Look inside nested blocks 8081 if (block->getBlockDecl()->capturesVariable(Variable)) 8082 Visit(block->getBlockDecl()->getBody()); 8083 } 8084 8085 void VisitOpaqueValueExpr(OpaqueValueExpr *OVE) { 8086 if (Capturer) return; 8087 if (OVE->getSourceExpr()) 8088 Visit(OVE->getSourceExpr()); 8089 } 8090 void VisitBinaryOperator(BinaryOperator *BinOp) { 8091 if (!Variable || VarWillBeReased || BinOp->getOpcode() != BO_Assign) 8092 return; 8093 Expr *LHS = BinOp->getLHS(); 8094 if (const DeclRefExpr *DRE = dyn_cast_or_null<DeclRefExpr>(LHS)) { 8095 if (DRE->getDecl() != Variable) 8096 return; 8097 if (Expr *RHS = BinOp->getRHS()) { 8098 RHS = RHS->IgnoreParenCasts(); 8099 llvm::APSInt Value; 8100 VarWillBeReased = 8101 (RHS && RHS->isIntegerConstantExpr(Value, Context) && Value == 0); 8102 } 8103 } 8104 } 8105 }; 8106 } 8107 8108 /// Check whether the given argument is a block which captures a 8109 /// variable. 8110 static Expr *findCapturingExpr(Sema &S, Expr *e, RetainCycleOwner &owner) { 8111 assert(owner.Variable && owner.Loc.isValid()); 8112 8113 e = e->IgnoreParenCasts(); 8114 8115 // Look through [^{...} copy] and Block_copy(^{...}). 8116 if (ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(e)) { 8117 Selector Cmd = ME->getSelector(); 8118 if (Cmd.isUnarySelector() && Cmd.getNameForSlot(0) == "copy") { 8119 e = ME->getInstanceReceiver(); 8120 if (!e) 8121 return nullptr; 8122 e = e->IgnoreParenCasts(); 8123 } 8124 } else if (CallExpr *CE = dyn_cast<CallExpr>(e)) { 8125 if (CE->getNumArgs() == 1) { 8126 FunctionDecl *Fn = dyn_cast_or_null<FunctionDecl>(CE->getCalleeDecl()); 8127 if (Fn) { 8128 const IdentifierInfo *FnI = Fn->getIdentifier(); 8129 if (FnI && FnI->isStr("_Block_copy")) { 8130 e = CE->getArg(0)->IgnoreParenCasts(); 8131 } 8132 } 8133 } 8134 } 8135 8136 BlockExpr *block = dyn_cast<BlockExpr>(e); 8137 if (!block || !block->getBlockDecl()->capturesVariable(owner.Variable)) 8138 return nullptr; 8139 8140 FindCaptureVisitor visitor(S.Context, owner.Variable); 8141 visitor.Visit(block->getBlockDecl()->getBody()); 8142 return visitor.VarWillBeReased ? nullptr : visitor.Capturer; 8143 } 8144 8145 static void diagnoseRetainCycle(Sema &S, Expr *capturer, 8146 RetainCycleOwner &owner) { 8147 assert(capturer); 8148 assert(owner.Variable && owner.Loc.isValid()); 8149 8150 S.Diag(capturer->getExprLoc(), diag::warn_arc_retain_cycle) 8151 << owner.Variable << capturer->getSourceRange(); 8152 S.Diag(owner.Loc, diag::note_arc_retain_cycle_owner) 8153 << owner.Indirect << owner.Range; 8154 } 8155 8156 /// Check for a keyword selector that starts with the word 'add' or 8157 /// 'set'. 8158 static bool isSetterLikeSelector(Selector sel) { 8159 if (sel.isUnarySelector()) return false; 8160 8161 StringRef str = sel.getNameForSlot(0); 8162 while (!str.empty() && str.front() == '_') str = str.substr(1); 8163 if (str.startswith("set")) 8164 str = str.substr(3); 8165 else if (str.startswith("add")) { 8166 // Specially whitelist 'addOperationWithBlock:'. 8167 if (sel.getNumArgs() == 1 && str.startswith("addOperationWithBlock")) 8168 return false; 8169 str = str.substr(3); 8170 } 8171 else 8172 return false; 8173 8174 if (str.empty()) return true; 8175 return !isLowercase(str.front()); 8176 } 8177 8178 /// Check a message send to see if it's likely to cause a retain cycle. 8179 void Sema::checkRetainCycles(ObjCMessageExpr *msg) { 8180 // Only check instance methods whose selector looks like a setter. 8181 if (!msg->isInstanceMessage() || !isSetterLikeSelector(msg->getSelector())) 8182 return; 8183 8184 // Try to find a variable that the receiver is strongly owned by. 8185 RetainCycleOwner owner; 8186 if (msg->getReceiverKind() == ObjCMessageExpr::Instance) { 8187 if (!findRetainCycleOwner(*this, msg->getInstanceReceiver(), owner)) 8188 return; 8189 } else { 8190 assert(msg->getReceiverKind() == ObjCMessageExpr::SuperInstance); 8191 owner.Variable = getCurMethodDecl()->getSelfDecl(); 8192 owner.Loc = msg->getSuperLoc(); 8193 owner.Range = msg->getSuperLoc(); 8194 } 8195 8196 // Check whether the receiver is captured by any of the arguments. 8197 for (unsigned i = 0, e = msg->getNumArgs(); i != e; ++i) 8198 if (Expr *capturer = findCapturingExpr(*this, msg->getArg(i), owner)) 8199 return diagnoseRetainCycle(*this, capturer, owner); 8200 } 8201 8202 /// Check a property assign to see if it's likely to cause a retain cycle. 8203 void Sema::checkRetainCycles(Expr *receiver, Expr *argument) { 8204 RetainCycleOwner owner; 8205 if (!findRetainCycleOwner(*this, receiver, owner)) 8206 return; 8207 8208 if (Expr *capturer = findCapturingExpr(*this, argument, owner)) 8209 diagnoseRetainCycle(*this, capturer, owner); 8210 } 8211 8212 void Sema::checkRetainCycles(VarDecl *Var, Expr *Init) { 8213 RetainCycleOwner Owner; 8214 if (!considerVariable(Var, /*DeclRefExpr=*/nullptr, Owner)) 8215 return; 8216 8217 // Because we don't have an expression for the variable, we have to set the 8218 // location explicitly here. 8219 Owner.Loc = Var->getLocation(); 8220 Owner.Range = Var->getSourceRange(); 8221 8222 if (Expr *Capturer = findCapturingExpr(*this, Init, Owner)) 8223 diagnoseRetainCycle(*this, Capturer, Owner); 8224 } 8225 8226 static bool checkUnsafeAssignLiteral(Sema &S, SourceLocation Loc, 8227 Expr *RHS, bool isProperty) { 8228 // Check if RHS is an Objective-C object literal, which also can get 8229 // immediately zapped in a weak reference. Note that we explicitly 8230 // allow ObjCStringLiterals, since those are designed to never really die. 8231 RHS = RHS->IgnoreParenImpCasts(); 8232 8233 // This enum needs to match with the 'select' in 8234 // warn_objc_arc_literal_assign (off-by-1). 8235 Sema::ObjCLiteralKind Kind = S.CheckLiteralKind(RHS); 8236 if (Kind == Sema::LK_String || Kind == Sema::LK_None) 8237 return false; 8238 8239 S.Diag(Loc, diag::warn_arc_literal_assign) 8240 << (unsigned) Kind 8241 << (isProperty ? 0 : 1) 8242 << RHS->getSourceRange(); 8243 8244 return true; 8245 } 8246 8247 static bool checkUnsafeAssignObject(Sema &S, SourceLocation Loc, 8248 Qualifiers::ObjCLifetime LT, 8249 Expr *RHS, bool isProperty) { 8250 // Strip off any implicit cast added to get to the one ARC-specific. 8251 while (ImplicitCastExpr *cast = dyn_cast<ImplicitCastExpr>(RHS)) { 8252 if (cast->getCastKind() == CK_ARCConsumeObject) { 8253 S.Diag(Loc, diag::warn_arc_retained_assign) 8254 << (LT == Qualifiers::OCL_ExplicitNone) 8255 << (isProperty ? 0 : 1) 8256 << RHS->getSourceRange(); 8257 return true; 8258 } 8259 RHS = cast->getSubExpr(); 8260 } 8261 8262 if (LT == Qualifiers::OCL_Weak && 8263 checkUnsafeAssignLiteral(S, Loc, RHS, isProperty)) 8264 return true; 8265 8266 return false; 8267 } 8268 8269 bool Sema::checkUnsafeAssigns(SourceLocation Loc, 8270 QualType LHS, Expr *RHS) { 8271 Qualifiers::ObjCLifetime LT = LHS.getObjCLifetime(); 8272 8273 if (LT != Qualifiers::OCL_Weak && LT != Qualifiers::OCL_ExplicitNone) 8274 return false; 8275 8276 if (checkUnsafeAssignObject(*this, Loc, LT, RHS, false)) 8277 return true; 8278 8279 return false; 8280 } 8281 8282 void Sema::checkUnsafeExprAssigns(SourceLocation Loc, 8283 Expr *LHS, Expr *RHS) { 8284 QualType LHSType; 8285 // PropertyRef on LHS type need be directly obtained from 8286 // its declaration as it has a PseudoType. 8287 ObjCPropertyRefExpr *PRE 8288 = dyn_cast<ObjCPropertyRefExpr>(LHS->IgnoreParens()); 8289 if (PRE && !PRE->isImplicitProperty()) { 8290 const ObjCPropertyDecl *PD = PRE->getExplicitProperty(); 8291 if (PD) 8292 LHSType = PD->getType(); 8293 } 8294 8295 if (LHSType.isNull()) 8296 LHSType = LHS->getType(); 8297 8298 Qualifiers::ObjCLifetime LT = LHSType.getObjCLifetime(); 8299 8300 if (LT == Qualifiers::OCL_Weak) { 8301 if (!Diags.isIgnored(diag::warn_arc_repeated_use_of_weak, Loc)) 8302 getCurFunction()->markSafeWeakUse(LHS); 8303 } 8304 8305 if (checkUnsafeAssigns(Loc, LHSType, RHS)) 8306 return; 8307 8308 // FIXME. Check for other life times. 8309 if (LT != Qualifiers::OCL_None) 8310 return; 8311 8312 if (PRE) { 8313 if (PRE->isImplicitProperty()) 8314 return; 8315 const ObjCPropertyDecl *PD = PRE->getExplicitProperty(); 8316 if (!PD) 8317 return; 8318 8319 unsigned Attributes = PD->getPropertyAttributes(); 8320 if (Attributes & ObjCPropertyDecl::OBJC_PR_assign) { 8321 // when 'assign' attribute was not explicitly specified 8322 // by user, ignore it and rely on property type itself 8323 // for lifetime info. 8324 unsigned AsWrittenAttr = PD->getPropertyAttributesAsWritten(); 8325 if (!(AsWrittenAttr & ObjCPropertyDecl::OBJC_PR_assign) && 8326 LHSType->isObjCRetainableType()) 8327 return; 8328 8329 while (ImplicitCastExpr *cast = dyn_cast<ImplicitCastExpr>(RHS)) { 8330 if (cast->getCastKind() == CK_ARCConsumeObject) { 8331 Diag(Loc, diag::warn_arc_retained_property_assign) 8332 << RHS->getSourceRange(); 8333 return; 8334 } 8335 RHS = cast->getSubExpr(); 8336 } 8337 } 8338 else if (Attributes & ObjCPropertyDecl::OBJC_PR_weak) { 8339 if (checkUnsafeAssignObject(*this, Loc, Qualifiers::OCL_Weak, RHS, true)) 8340 return; 8341 } 8342 } 8343 } 8344 8345 //===--- CHECK: Empty statement body (-Wempty-body) ---------------------===// 8346 8347 namespace { 8348 bool ShouldDiagnoseEmptyStmtBody(const SourceManager &SourceMgr, 8349 SourceLocation StmtLoc, 8350 const NullStmt *Body) { 8351 // Do not warn if the body is a macro that expands to nothing, e.g: 8352 // 8353 // #define CALL(x) 8354 // if (condition) 8355 // CALL(0); 8356 // 8357 if (Body->hasLeadingEmptyMacro()) 8358 return false; 8359 8360 // Get line numbers of statement and body. 8361 bool StmtLineInvalid; 8362 unsigned StmtLine = SourceMgr.getSpellingLineNumber(StmtLoc, 8363 &StmtLineInvalid); 8364 if (StmtLineInvalid) 8365 return false; 8366 8367 bool BodyLineInvalid; 8368 unsigned BodyLine = SourceMgr.getSpellingLineNumber(Body->getSemiLoc(), 8369 &BodyLineInvalid); 8370 if (BodyLineInvalid) 8371 return false; 8372 8373 // Warn if null statement and body are on the same line. 8374 if (StmtLine != BodyLine) 8375 return false; 8376 8377 return true; 8378 } 8379 } // Unnamed namespace 8380 8381 void Sema::DiagnoseEmptyStmtBody(SourceLocation StmtLoc, 8382 const Stmt *Body, 8383 unsigned DiagID) { 8384 // Since this is a syntactic check, don't emit diagnostic for template 8385 // instantiations, this just adds noise. 8386 if (CurrentInstantiationScope) 8387 return; 8388 8389 // The body should be a null statement. 8390 const NullStmt *NBody = dyn_cast<NullStmt>(Body); 8391 if (!NBody) 8392 return; 8393 8394 // Do the usual checks. 8395 if (!ShouldDiagnoseEmptyStmtBody(SourceMgr, StmtLoc, NBody)) 8396 return; 8397 8398 Diag(NBody->getSemiLoc(), DiagID); 8399 Diag(NBody->getSemiLoc(), diag::note_empty_body_on_separate_line); 8400 } 8401 8402 void Sema::DiagnoseEmptyLoopBody(const Stmt *S, 8403 const Stmt *PossibleBody) { 8404 assert(!CurrentInstantiationScope); // Ensured by caller 8405 8406 SourceLocation StmtLoc; 8407 const Stmt *Body; 8408 unsigned DiagID; 8409 if (const ForStmt *FS = dyn_cast<ForStmt>(S)) { 8410 StmtLoc = FS->getRParenLoc(); 8411 Body = FS->getBody(); 8412 DiagID = diag::warn_empty_for_body; 8413 } else if (const WhileStmt *WS = dyn_cast<WhileStmt>(S)) { 8414 StmtLoc = WS->getCond()->getSourceRange().getEnd(); 8415 Body = WS->getBody(); 8416 DiagID = diag::warn_empty_while_body; 8417 } else 8418 return; // Neither `for' nor `while'. 8419 8420 // The body should be a null statement. 8421 const NullStmt *NBody = dyn_cast<NullStmt>(Body); 8422 if (!NBody) 8423 return; 8424 8425 // Skip expensive checks if diagnostic is disabled. 8426 if (Diags.isIgnored(DiagID, NBody->getSemiLoc())) 8427 return; 8428 8429 // Do the usual checks. 8430 if (!ShouldDiagnoseEmptyStmtBody(SourceMgr, StmtLoc, NBody)) 8431 return; 8432 8433 // `for(...);' and `while(...);' are popular idioms, so in order to keep 8434 // noise level low, emit diagnostics only if for/while is followed by a 8435 // CompoundStmt, e.g.: 8436 // for (int i = 0; i < n; i++); 8437 // { 8438 // a(i); 8439 // } 8440 // or if for/while is followed by a statement with more indentation 8441 // than for/while itself: 8442 // for (int i = 0; i < n; i++); 8443 // a(i); 8444 bool ProbableTypo = isa<CompoundStmt>(PossibleBody); 8445 if (!ProbableTypo) { 8446 bool BodyColInvalid; 8447 unsigned BodyCol = SourceMgr.getPresumedColumnNumber( 8448 PossibleBody->getLocStart(), 8449 &BodyColInvalid); 8450 if (BodyColInvalid) 8451 return; 8452 8453 bool StmtColInvalid; 8454 unsigned StmtCol = SourceMgr.getPresumedColumnNumber( 8455 S->getLocStart(), 8456 &StmtColInvalid); 8457 if (StmtColInvalid) 8458 return; 8459 8460 if (BodyCol > StmtCol) 8461 ProbableTypo = true; 8462 } 8463 8464 if (ProbableTypo) { 8465 Diag(NBody->getSemiLoc(), DiagID); 8466 Diag(NBody->getSemiLoc(), diag::note_empty_body_on_separate_line); 8467 } 8468 } 8469 8470 //===--- CHECK: Warn on self move with std::move. -------------------------===// 8471 8472 /// DiagnoseSelfMove - Emits a warning if a value is moved to itself. 8473 void Sema::DiagnoseSelfMove(const Expr *LHSExpr, const Expr *RHSExpr, 8474 SourceLocation OpLoc) { 8475 8476 if (Diags.isIgnored(diag::warn_sizeof_pointer_expr_memaccess, OpLoc)) 8477 return; 8478 8479 if (!ActiveTemplateInstantiations.empty()) 8480 return; 8481 8482 // Strip parens and casts away. 8483 LHSExpr = LHSExpr->IgnoreParenImpCasts(); 8484 RHSExpr = RHSExpr->IgnoreParenImpCasts(); 8485 8486 // Check for a call expression 8487 const CallExpr *CE = dyn_cast<CallExpr>(RHSExpr); 8488 if (!CE || CE->getNumArgs() != 1) 8489 return; 8490 8491 // Check for a call to std::move 8492 const FunctionDecl *FD = CE->getDirectCallee(); 8493 if (!FD || !FD->isInStdNamespace() || !FD->getIdentifier() || 8494 !FD->getIdentifier()->isStr("move")) 8495 return; 8496 8497 // Get argument from std::move 8498 RHSExpr = CE->getArg(0); 8499 8500 const DeclRefExpr *LHSDeclRef = dyn_cast<DeclRefExpr>(LHSExpr); 8501 const DeclRefExpr *RHSDeclRef = dyn_cast<DeclRefExpr>(RHSExpr); 8502 8503 // Two DeclRefExpr's, check that the decls are the same. 8504 if (LHSDeclRef && RHSDeclRef) { 8505 if (!LHSDeclRef->getDecl() || !RHSDeclRef->getDecl()) 8506 return; 8507 if (LHSDeclRef->getDecl()->getCanonicalDecl() != 8508 RHSDeclRef->getDecl()->getCanonicalDecl()) 8509 return; 8510 8511 Diag(OpLoc, diag::warn_self_move) << LHSExpr->getType() 8512 << LHSExpr->getSourceRange() 8513 << RHSExpr->getSourceRange(); 8514 return; 8515 } 8516 8517 // Member variables require a different approach to check for self moves. 8518 // MemberExpr's are the same if every nested MemberExpr refers to the same 8519 // Decl and that the base Expr's are DeclRefExpr's with the same Decl or 8520 // the base Expr's are CXXThisExpr's. 8521 const Expr *LHSBase = LHSExpr; 8522 const Expr *RHSBase = RHSExpr; 8523 const MemberExpr *LHSME = dyn_cast<MemberExpr>(LHSExpr); 8524 const MemberExpr *RHSME = dyn_cast<MemberExpr>(RHSExpr); 8525 if (!LHSME || !RHSME) 8526 return; 8527 8528 while (LHSME && RHSME) { 8529 if (LHSME->getMemberDecl()->getCanonicalDecl() != 8530 RHSME->getMemberDecl()->getCanonicalDecl()) 8531 return; 8532 8533 LHSBase = LHSME->getBase(); 8534 RHSBase = RHSME->getBase(); 8535 LHSME = dyn_cast<MemberExpr>(LHSBase); 8536 RHSME = dyn_cast<MemberExpr>(RHSBase); 8537 } 8538 8539 LHSDeclRef = dyn_cast<DeclRefExpr>(LHSBase); 8540 RHSDeclRef = dyn_cast<DeclRefExpr>(RHSBase); 8541 if (LHSDeclRef && RHSDeclRef) { 8542 if (!LHSDeclRef->getDecl() || !RHSDeclRef->getDecl()) 8543 return; 8544 if (LHSDeclRef->getDecl()->getCanonicalDecl() != 8545 RHSDeclRef->getDecl()->getCanonicalDecl()) 8546 return; 8547 8548 Diag(OpLoc, diag::warn_self_move) << LHSExpr->getType() 8549 << LHSExpr->getSourceRange() 8550 << RHSExpr->getSourceRange(); 8551 return; 8552 } 8553 8554 if (isa<CXXThisExpr>(LHSBase) && isa<CXXThisExpr>(RHSBase)) 8555 Diag(OpLoc, diag::warn_self_move) << LHSExpr->getType() 8556 << LHSExpr->getSourceRange() 8557 << RHSExpr->getSourceRange(); 8558 } 8559 8560 //===--- Layout compatibility ----------------------------------------------// 8561 8562 namespace { 8563 8564 bool isLayoutCompatible(ASTContext &C, QualType T1, QualType T2); 8565 8566 /// \brief Check if two enumeration types are layout-compatible. 8567 bool isLayoutCompatible(ASTContext &C, EnumDecl *ED1, EnumDecl *ED2) { 8568 // C++11 [dcl.enum] p8: 8569 // Two enumeration types are layout-compatible if they have the same 8570 // underlying type. 8571 return ED1->isComplete() && ED2->isComplete() && 8572 C.hasSameType(ED1->getIntegerType(), ED2->getIntegerType()); 8573 } 8574 8575 /// \brief Check if two fields are layout-compatible. 8576 bool isLayoutCompatible(ASTContext &C, FieldDecl *Field1, FieldDecl *Field2) { 8577 if (!isLayoutCompatible(C, Field1->getType(), Field2->getType())) 8578 return false; 8579 8580 if (Field1->isBitField() != Field2->isBitField()) 8581 return false; 8582 8583 if (Field1->isBitField()) { 8584 // Make sure that the bit-fields are the same length. 8585 unsigned Bits1 = Field1->getBitWidthValue(C); 8586 unsigned Bits2 = Field2->getBitWidthValue(C); 8587 8588 if (Bits1 != Bits2) 8589 return false; 8590 } 8591 8592 return true; 8593 } 8594 8595 /// \brief Check if two standard-layout structs are layout-compatible. 8596 /// (C++11 [class.mem] p17) 8597 bool isLayoutCompatibleStruct(ASTContext &C, 8598 RecordDecl *RD1, 8599 RecordDecl *RD2) { 8600 // If both records are C++ classes, check that base classes match. 8601 if (const CXXRecordDecl *D1CXX = dyn_cast<CXXRecordDecl>(RD1)) { 8602 // If one of records is a CXXRecordDecl we are in C++ mode, 8603 // thus the other one is a CXXRecordDecl, too. 8604 const CXXRecordDecl *D2CXX = cast<CXXRecordDecl>(RD2); 8605 // Check number of base classes. 8606 if (D1CXX->getNumBases() != D2CXX->getNumBases()) 8607 return false; 8608 8609 // Check the base classes. 8610 for (CXXRecordDecl::base_class_const_iterator 8611 Base1 = D1CXX->bases_begin(), 8612 BaseEnd1 = D1CXX->bases_end(), 8613 Base2 = D2CXX->bases_begin(); 8614 Base1 != BaseEnd1; 8615 ++Base1, ++Base2) { 8616 if (!isLayoutCompatible(C, Base1->getType(), Base2->getType())) 8617 return false; 8618 } 8619 } else if (const CXXRecordDecl *D2CXX = dyn_cast<CXXRecordDecl>(RD2)) { 8620 // If only RD2 is a C++ class, it should have zero base classes. 8621 if (D2CXX->getNumBases() > 0) 8622 return false; 8623 } 8624 8625 // Check the fields. 8626 RecordDecl::field_iterator Field2 = RD2->field_begin(), 8627 Field2End = RD2->field_end(), 8628 Field1 = RD1->field_begin(), 8629 Field1End = RD1->field_end(); 8630 for ( ; Field1 != Field1End && Field2 != Field2End; ++Field1, ++Field2) { 8631 if (!isLayoutCompatible(C, *Field1, *Field2)) 8632 return false; 8633 } 8634 if (Field1 != Field1End || Field2 != Field2End) 8635 return false; 8636 8637 return true; 8638 } 8639 8640 /// \brief Check if two standard-layout unions are layout-compatible. 8641 /// (C++11 [class.mem] p18) 8642 bool isLayoutCompatibleUnion(ASTContext &C, 8643 RecordDecl *RD1, 8644 RecordDecl *RD2) { 8645 llvm::SmallPtrSet<FieldDecl *, 8> UnmatchedFields; 8646 for (auto *Field2 : RD2->fields()) 8647 UnmatchedFields.insert(Field2); 8648 8649 for (auto *Field1 : RD1->fields()) { 8650 llvm::SmallPtrSet<FieldDecl *, 8>::iterator 8651 I = UnmatchedFields.begin(), 8652 E = UnmatchedFields.end(); 8653 8654 for ( ; I != E; ++I) { 8655 if (isLayoutCompatible(C, Field1, *I)) { 8656 bool Result = UnmatchedFields.erase(*I); 8657 (void) Result; 8658 assert(Result); 8659 break; 8660 } 8661 } 8662 if (I == E) 8663 return false; 8664 } 8665 8666 return UnmatchedFields.empty(); 8667 } 8668 8669 bool isLayoutCompatible(ASTContext &C, RecordDecl *RD1, RecordDecl *RD2) { 8670 if (RD1->isUnion() != RD2->isUnion()) 8671 return false; 8672 8673 if (RD1->isUnion()) 8674 return isLayoutCompatibleUnion(C, RD1, RD2); 8675 else 8676 return isLayoutCompatibleStruct(C, RD1, RD2); 8677 } 8678 8679 /// \brief Check if two types are layout-compatible in C++11 sense. 8680 bool isLayoutCompatible(ASTContext &C, QualType T1, QualType T2) { 8681 if (T1.isNull() || T2.isNull()) 8682 return false; 8683 8684 // C++11 [basic.types] p11: 8685 // If two types T1 and T2 are the same type, then T1 and T2 are 8686 // layout-compatible types. 8687 if (C.hasSameType(T1, T2)) 8688 return true; 8689 8690 T1 = T1.getCanonicalType().getUnqualifiedType(); 8691 T2 = T2.getCanonicalType().getUnqualifiedType(); 8692 8693 const Type::TypeClass TC1 = T1->getTypeClass(); 8694 const Type::TypeClass TC2 = T2->getTypeClass(); 8695 8696 if (TC1 != TC2) 8697 return false; 8698 8699 if (TC1 == Type::Enum) { 8700 return isLayoutCompatible(C, 8701 cast<EnumType>(T1)->getDecl(), 8702 cast<EnumType>(T2)->getDecl()); 8703 } else if (TC1 == Type::Record) { 8704 if (!T1->isStandardLayoutType() || !T2->isStandardLayoutType()) 8705 return false; 8706 8707 return isLayoutCompatible(C, 8708 cast<RecordType>(T1)->getDecl(), 8709 cast<RecordType>(T2)->getDecl()); 8710 } 8711 8712 return false; 8713 } 8714 } 8715 8716 //===--- CHECK: pointer_with_type_tag attribute: datatypes should match ----// 8717 8718 namespace { 8719 /// \brief Given a type tag expression find the type tag itself. 8720 /// 8721 /// \param TypeExpr Type tag expression, as it appears in user's code. 8722 /// 8723 /// \param VD Declaration of an identifier that appears in a type tag. 8724 /// 8725 /// \param MagicValue Type tag magic value. 8726 bool FindTypeTagExpr(const Expr *TypeExpr, const ASTContext &Ctx, 8727 const ValueDecl **VD, uint64_t *MagicValue) { 8728 while(true) { 8729 if (!TypeExpr) 8730 return false; 8731 8732 TypeExpr = TypeExpr->IgnoreParenImpCasts()->IgnoreParenCasts(); 8733 8734 switch (TypeExpr->getStmtClass()) { 8735 case Stmt::UnaryOperatorClass: { 8736 const UnaryOperator *UO = cast<UnaryOperator>(TypeExpr); 8737 if (UO->getOpcode() == UO_AddrOf || UO->getOpcode() == UO_Deref) { 8738 TypeExpr = UO->getSubExpr(); 8739 continue; 8740 } 8741 return false; 8742 } 8743 8744 case Stmt::DeclRefExprClass: { 8745 const DeclRefExpr *DRE = cast<DeclRefExpr>(TypeExpr); 8746 *VD = DRE->getDecl(); 8747 return true; 8748 } 8749 8750 case Stmt::IntegerLiteralClass: { 8751 const IntegerLiteral *IL = cast<IntegerLiteral>(TypeExpr); 8752 llvm::APInt MagicValueAPInt = IL->getValue(); 8753 if (MagicValueAPInt.getActiveBits() <= 64) { 8754 *MagicValue = MagicValueAPInt.getZExtValue(); 8755 return true; 8756 } else 8757 return false; 8758 } 8759 8760 case Stmt::BinaryConditionalOperatorClass: 8761 case Stmt::ConditionalOperatorClass: { 8762 const AbstractConditionalOperator *ACO = 8763 cast<AbstractConditionalOperator>(TypeExpr); 8764 bool Result; 8765 if (ACO->getCond()->EvaluateAsBooleanCondition(Result, Ctx)) { 8766 if (Result) 8767 TypeExpr = ACO->getTrueExpr(); 8768 else 8769 TypeExpr = ACO->getFalseExpr(); 8770 continue; 8771 } 8772 return false; 8773 } 8774 8775 case Stmt::BinaryOperatorClass: { 8776 const BinaryOperator *BO = cast<BinaryOperator>(TypeExpr); 8777 if (BO->getOpcode() == BO_Comma) { 8778 TypeExpr = BO->getRHS(); 8779 continue; 8780 } 8781 return false; 8782 } 8783 8784 default: 8785 return false; 8786 } 8787 } 8788 } 8789 8790 /// \brief Retrieve the C type corresponding to type tag TypeExpr. 8791 /// 8792 /// \param TypeExpr Expression that specifies a type tag. 8793 /// 8794 /// \param MagicValues Registered magic values. 8795 /// 8796 /// \param FoundWrongKind Set to true if a type tag was found, but of a wrong 8797 /// kind. 8798 /// 8799 /// \param TypeInfo Information about the corresponding C type. 8800 /// 8801 /// \returns true if the corresponding C type was found. 8802 bool GetMatchingCType( 8803 const IdentifierInfo *ArgumentKind, 8804 const Expr *TypeExpr, const ASTContext &Ctx, 8805 const llvm::DenseMap<Sema::TypeTagMagicValue, 8806 Sema::TypeTagData> *MagicValues, 8807 bool &FoundWrongKind, 8808 Sema::TypeTagData &TypeInfo) { 8809 FoundWrongKind = false; 8810 8811 // Variable declaration that has type_tag_for_datatype attribute. 8812 const ValueDecl *VD = nullptr; 8813 8814 uint64_t MagicValue; 8815 8816 if (!FindTypeTagExpr(TypeExpr, Ctx, &VD, &MagicValue)) 8817 return false; 8818 8819 if (VD) { 8820 if (TypeTagForDatatypeAttr *I = VD->getAttr<TypeTagForDatatypeAttr>()) { 8821 if (I->getArgumentKind() != ArgumentKind) { 8822 FoundWrongKind = true; 8823 return false; 8824 } 8825 TypeInfo.Type = I->getMatchingCType(); 8826 TypeInfo.LayoutCompatible = I->getLayoutCompatible(); 8827 TypeInfo.MustBeNull = I->getMustBeNull(); 8828 return true; 8829 } 8830 return false; 8831 } 8832 8833 if (!MagicValues) 8834 return false; 8835 8836 llvm::DenseMap<Sema::TypeTagMagicValue, 8837 Sema::TypeTagData>::const_iterator I = 8838 MagicValues->find(std::make_pair(ArgumentKind, MagicValue)); 8839 if (I == MagicValues->end()) 8840 return false; 8841 8842 TypeInfo = I->second; 8843 return true; 8844 } 8845 } // unnamed namespace 8846 8847 void Sema::RegisterTypeTagForDatatype(const IdentifierInfo *ArgumentKind, 8848 uint64_t MagicValue, QualType Type, 8849 bool LayoutCompatible, 8850 bool MustBeNull) { 8851 if (!TypeTagForDatatypeMagicValues) 8852 TypeTagForDatatypeMagicValues.reset( 8853 new llvm::DenseMap<TypeTagMagicValue, TypeTagData>); 8854 8855 TypeTagMagicValue Magic(ArgumentKind, MagicValue); 8856 (*TypeTagForDatatypeMagicValues)[Magic] = 8857 TypeTagData(Type, LayoutCompatible, MustBeNull); 8858 } 8859 8860 namespace { 8861 bool IsSameCharType(QualType T1, QualType T2) { 8862 const BuiltinType *BT1 = T1->getAs<BuiltinType>(); 8863 if (!BT1) 8864 return false; 8865 8866 const BuiltinType *BT2 = T2->getAs<BuiltinType>(); 8867 if (!BT2) 8868 return false; 8869 8870 BuiltinType::Kind T1Kind = BT1->getKind(); 8871 BuiltinType::Kind T2Kind = BT2->getKind(); 8872 8873 return (T1Kind == BuiltinType::SChar && T2Kind == BuiltinType::Char_S) || 8874 (T1Kind == BuiltinType::UChar && T2Kind == BuiltinType::Char_U) || 8875 (T1Kind == BuiltinType::Char_U && T2Kind == BuiltinType::UChar) || 8876 (T1Kind == BuiltinType::Char_S && T2Kind == BuiltinType::SChar); 8877 } 8878 } // unnamed namespace 8879 8880 void Sema::CheckArgumentWithTypeTag(const ArgumentWithTypeTagAttr *Attr, 8881 const Expr * const *ExprArgs) { 8882 const IdentifierInfo *ArgumentKind = Attr->getArgumentKind(); 8883 bool IsPointerAttr = Attr->getIsPointer(); 8884 8885 const Expr *TypeTagExpr = ExprArgs[Attr->getTypeTagIdx()]; 8886 bool FoundWrongKind; 8887 TypeTagData TypeInfo; 8888 if (!GetMatchingCType(ArgumentKind, TypeTagExpr, Context, 8889 TypeTagForDatatypeMagicValues.get(), 8890 FoundWrongKind, TypeInfo)) { 8891 if (FoundWrongKind) 8892 Diag(TypeTagExpr->getExprLoc(), 8893 diag::warn_type_tag_for_datatype_wrong_kind) 8894 << TypeTagExpr->getSourceRange(); 8895 return; 8896 } 8897 8898 const Expr *ArgumentExpr = ExprArgs[Attr->getArgumentIdx()]; 8899 if (IsPointerAttr) { 8900 // Skip implicit cast of pointer to `void *' (as a function argument). 8901 if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(ArgumentExpr)) 8902 if (ICE->getType()->isVoidPointerType() && 8903 ICE->getCastKind() == CK_BitCast) 8904 ArgumentExpr = ICE->getSubExpr(); 8905 } 8906 QualType ArgumentType = ArgumentExpr->getType(); 8907 8908 // Passing a `void*' pointer shouldn't trigger a warning. 8909 if (IsPointerAttr && ArgumentType->isVoidPointerType()) 8910 return; 8911 8912 if (TypeInfo.MustBeNull) { 8913 // Type tag with matching void type requires a null pointer. 8914 if (!ArgumentExpr->isNullPointerConstant(Context, 8915 Expr::NPC_ValueDependentIsNotNull)) { 8916 Diag(ArgumentExpr->getExprLoc(), 8917 diag::warn_type_safety_null_pointer_required) 8918 << ArgumentKind->getName() 8919 << ArgumentExpr->getSourceRange() 8920 << TypeTagExpr->getSourceRange(); 8921 } 8922 return; 8923 } 8924 8925 QualType RequiredType = TypeInfo.Type; 8926 if (IsPointerAttr) 8927 RequiredType = Context.getPointerType(RequiredType); 8928 8929 bool mismatch = false; 8930 if (!TypeInfo.LayoutCompatible) { 8931 mismatch = !Context.hasSameType(ArgumentType, RequiredType); 8932 8933 // C++11 [basic.fundamental] p1: 8934 // Plain char, signed char, and unsigned char are three distinct types. 8935 // 8936 // But we treat plain `char' as equivalent to `signed char' or `unsigned 8937 // char' depending on the current char signedness mode. 8938 if (mismatch) 8939 if ((IsPointerAttr && IsSameCharType(ArgumentType->getPointeeType(), 8940 RequiredType->getPointeeType())) || 8941 (!IsPointerAttr && IsSameCharType(ArgumentType, RequiredType))) 8942 mismatch = false; 8943 } else 8944 if (IsPointerAttr) 8945 mismatch = !isLayoutCompatible(Context, 8946 ArgumentType->getPointeeType(), 8947 RequiredType->getPointeeType()); 8948 else 8949 mismatch = !isLayoutCompatible(Context, ArgumentType, RequiredType); 8950 8951 if (mismatch) 8952 Diag(ArgumentExpr->getExprLoc(), diag::warn_type_safety_type_mismatch) 8953 << ArgumentType << ArgumentKind 8954 << TypeInfo.LayoutCompatible << RequiredType 8955 << ArgumentExpr->getSourceRange() 8956 << TypeTagExpr->getSourceRange(); 8957 } 8958 8959