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(S.Context); 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 D << FixIt; 3156 } else { 3157 S.Diag(IsStringLocation ? ArgumentExpr->getExprLoc() : Loc, PDiag) 3158 << ArgumentExpr->getSourceRange(); 3159 3160 const Sema::SemaDiagnosticBuilder &Note = 3161 S.Diag(IsStringLocation ? Loc : StringRange.getBegin(), 3162 diag::note_format_string_defined); 3163 3164 Note << StringRange; 3165 Note << FixIt; 3166 } 3167 } 3168 3169 //===--- CHECK: Printf format string checking ------------------------------===// 3170 3171 namespace { 3172 class CheckPrintfHandler : public CheckFormatHandler { 3173 bool ObjCContext; 3174 public: 3175 CheckPrintfHandler(Sema &s, const StringLiteral *fexpr, 3176 const Expr *origFormatExpr, unsigned firstDataArg, 3177 unsigned numDataArgs, bool isObjC, 3178 const char *beg, bool hasVAListArg, 3179 ArrayRef<const Expr *> Args, 3180 unsigned formatIdx, bool inFunctionCall, 3181 Sema::VariadicCallType CallType, 3182 llvm::SmallBitVector &CheckedVarArgs) 3183 : CheckFormatHandler(s, fexpr, origFormatExpr, firstDataArg, 3184 numDataArgs, beg, hasVAListArg, Args, 3185 formatIdx, inFunctionCall, CallType, CheckedVarArgs), 3186 ObjCContext(isObjC) 3187 {} 3188 3189 3190 bool HandleInvalidPrintfConversionSpecifier( 3191 const analyze_printf::PrintfSpecifier &FS, 3192 const char *startSpecifier, 3193 unsigned specifierLen) override; 3194 3195 bool HandlePrintfSpecifier(const analyze_printf::PrintfSpecifier &FS, 3196 const char *startSpecifier, 3197 unsigned specifierLen) override; 3198 bool checkFormatExpr(const analyze_printf::PrintfSpecifier &FS, 3199 const char *StartSpecifier, 3200 unsigned SpecifierLen, 3201 const Expr *E); 3202 3203 bool HandleAmount(const analyze_format_string::OptionalAmount &Amt, unsigned k, 3204 const char *startSpecifier, unsigned specifierLen); 3205 void HandleInvalidAmount(const analyze_printf::PrintfSpecifier &FS, 3206 const analyze_printf::OptionalAmount &Amt, 3207 unsigned type, 3208 const char *startSpecifier, unsigned specifierLen); 3209 void HandleFlag(const analyze_printf::PrintfSpecifier &FS, 3210 const analyze_printf::OptionalFlag &flag, 3211 const char *startSpecifier, unsigned specifierLen); 3212 void HandleIgnoredFlag(const analyze_printf::PrintfSpecifier &FS, 3213 const analyze_printf::OptionalFlag &ignoredFlag, 3214 const analyze_printf::OptionalFlag &flag, 3215 const char *startSpecifier, unsigned specifierLen); 3216 bool checkForCStrMembers(const analyze_printf::ArgType &AT, 3217 const Expr *E); 3218 3219 }; 3220 } 3221 3222 bool CheckPrintfHandler::HandleInvalidPrintfConversionSpecifier( 3223 const analyze_printf::PrintfSpecifier &FS, 3224 const char *startSpecifier, 3225 unsigned specifierLen) { 3226 const analyze_printf::PrintfConversionSpecifier &CS = 3227 FS.getConversionSpecifier(); 3228 3229 return HandleInvalidConversionSpecifier(FS.getArgIndex(), 3230 getLocationOfByte(CS.getStart()), 3231 startSpecifier, specifierLen, 3232 CS.getStart(), CS.getLength()); 3233 } 3234 3235 bool CheckPrintfHandler::HandleAmount( 3236 const analyze_format_string::OptionalAmount &Amt, 3237 unsigned k, const char *startSpecifier, 3238 unsigned specifierLen) { 3239 3240 if (Amt.hasDataArgument()) { 3241 if (!HasVAListArg) { 3242 unsigned argIndex = Amt.getArgIndex(); 3243 if (argIndex >= NumDataArgs) { 3244 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_asterisk_missing_arg) 3245 << k, 3246 getLocationOfByte(Amt.getStart()), 3247 /*IsStringLocation*/true, 3248 getSpecifierRange(startSpecifier, specifierLen)); 3249 // Don't do any more checking. We will just emit 3250 // spurious errors. 3251 return false; 3252 } 3253 3254 // Type check the data argument. It should be an 'int'. 3255 // Although not in conformance with C99, we also allow the argument to be 3256 // an 'unsigned int' as that is a reasonably safe case. GCC also 3257 // doesn't emit a warning for that case. 3258 CoveredArgs.set(argIndex); 3259 const Expr *Arg = getDataArg(argIndex); 3260 if (!Arg) 3261 return false; 3262 3263 QualType T = Arg->getType(); 3264 3265 const analyze_printf::ArgType &AT = Amt.getArgType(S.Context); 3266 assert(AT.isValid()); 3267 3268 if (!AT.matchesType(S.Context, T)) { 3269 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_asterisk_wrong_type) 3270 << k << AT.getRepresentativeTypeName(S.Context) 3271 << T << Arg->getSourceRange(), 3272 getLocationOfByte(Amt.getStart()), 3273 /*IsStringLocation*/true, 3274 getSpecifierRange(startSpecifier, specifierLen)); 3275 // Don't do any more checking. We will just emit 3276 // spurious errors. 3277 return false; 3278 } 3279 } 3280 } 3281 return true; 3282 } 3283 3284 void CheckPrintfHandler::HandleInvalidAmount( 3285 const analyze_printf::PrintfSpecifier &FS, 3286 const analyze_printf::OptionalAmount &Amt, 3287 unsigned type, 3288 const char *startSpecifier, 3289 unsigned specifierLen) { 3290 const analyze_printf::PrintfConversionSpecifier &CS = 3291 FS.getConversionSpecifier(); 3292 3293 FixItHint fixit = 3294 Amt.getHowSpecified() == analyze_printf::OptionalAmount::Constant 3295 ? FixItHint::CreateRemoval(getSpecifierRange(Amt.getStart(), 3296 Amt.getConstantLength())) 3297 : FixItHint(); 3298 3299 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_nonsensical_optional_amount) 3300 << type << CS.toString(), 3301 getLocationOfByte(Amt.getStart()), 3302 /*IsStringLocation*/true, 3303 getSpecifierRange(startSpecifier, specifierLen), 3304 fixit); 3305 } 3306 3307 void CheckPrintfHandler::HandleFlag(const analyze_printf::PrintfSpecifier &FS, 3308 const analyze_printf::OptionalFlag &flag, 3309 const char *startSpecifier, 3310 unsigned specifierLen) { 3311 // Warn about pointless flag with a fixit removal. 3312 const analyze_printf::PrintfConversionSpecifier &CS = 3313 FS.getConversionSpecifier(); 3314 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_nonsensical_flag) 3315 << flag.toString() << CS.toString(), 3316 getLocationOfByte(flag.getPosition()), 3317 /*IsStringLocation*/true, 3318 getSpecifierRange(startSpecifier, specifierLen), 3319 FixItHint::CreateRemoval( 3320 getSpecifierRange(flag.getPosition(), 1))); 3321 } 3322 3323 void CheckPrintfHandler::HandleIgnoredFlag( 3324 const analyze_printf::PrintfSpecifier &FS, 3325 const analyze_printf::OptionalFlag &ignoredFlag, 3326 const analyze_printf::OptionalFlag &flag, 3327 const char *startSpecifier, 3328 unsigned specifierLen) { 3329 // Warn about ignored flag with a fixit removal. 3330 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_ignored_flag) 3331 << ignoredFlag.toString() << flag.toString(), 3332 getLocationOfByte(ignoredFlag.getPosition()), 3333 /*IsStringLocation*/true, 3334 getSpecifierRange(startSpecifier, specifierLen), 3335 FixItHint::CreateRemoval( 3336 getSpecifierRange(ignoredFlag.getPosition(), 1))); 3337 } 3338 3339 // Determines if the specified is a C++ class or struct containing 3340 // a member with the specified name and kind (e.g. a CXXMethodDecl named 3341 // "c_str()"). 3342 template<typename MemberKind> 3343 static llvm::SmallPtrSet<MemberKind*, 1> 3344 CXXRecordMembersNamed(StringRef Name, Sema &S, QualType Ty) { 3345 const RecordType *RT = Ty->getAs<RecordType>(); 3346 llvm::SmallPtrSet<MemberKind*, 1> Results; 3347 3348 if (!RT) 3349 return Results; 3350 const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(RT->getDecl()); 3351 if (!RD || !RD->getDefinition()) 3352 return Results; 3353 3354 LookupResult R(S, &S.Context.Idents.get(Name), SourceLocation(), 3355 Sema::LookupMemberName); 3356 R.suppressDiagnostics(); 3357 3358 // We just need to include all members of the right kind turned up by the 3359 // filter, at this point. 3360 if (S.LookupQualifiedName(R, RT->getDecl())) 3361 for (LookupResult::iterator I = R.begin(), E = R.end(); I != E; ++I) { 3362 NamedDecl *decl = (*I)->getUnderlyingDecl(); 3363 if (MemberKind *FK = dyn_cast<MemberKind>(decl)) 3364 Results.insert(FK); 3365 } 3366 return Results; 3367 } 3368 3369 /// Check if we could call '.c_str()' on an object. 3370 /// 3371 /// FIXME: This returns the wrong results in some cases (if cv-qualifiers don't 3372 /// allow the call, or if it would be ambiguous). 3373 bool Sema::hasCStrMethod(const Expr *E) { 3374 typedef llvm::SmallPtrSet<CXXMethodDecl*, 1> MethodSet; 3375 MethodSet Results = 3376 CXXRecordMembersNamed<CXXMethodDecl>("c_str", *this, E->getType()); 3377 for (MethodSet::iterator MI = Results.begin(), ME = Results.end(); 3378 MI != ME; ++MI) 3379 if ((*MI)->getMinRequiredArguments() == 0) 3380 return true; 3381 return false; 3382 } 3383 3384 // Check if a (w)string was passed when a (w)char* was needed, and offer a 3385 // better diagnostic if so. AT is assumed to be valid. 3386 // Returns true when a c_str() conversion method is found. 3387 bool CheckPrintfHandler::checkForCStrMembers( 3388 const analyze_printf::ArgType &AT, const Expr *E) { 3389 typedef llvm::SmallPtrSet<CXXMethodDecl*, 1> MethodSet; 3390 3391 MethodSet Results = 3392 CXXRecordMembersNamed<CXXMethodDecl>("c_str", S, E->getType()); 3393 3394 for (MethodSet::iterator MI = Results.begin(), ME = Results.end(); 3395 MI != ME; ++MI) { 3396 const CXXMethodDecl *Method = *MI; 3397 if (Method->getMinRequiredArguments() == 0 && 3398 AT.matchesType(S.Context, Method->getReturnType())) { 3399 // FIXME: Suggest parens if the expression needs them. 3400 SourceLocation EndLoc = S.getLocForEndOfToken(E->getLocEnd()); 3401 S.Diag(E->getLocStart(), diag::note_printf_c_str) 3402 << "c_str()" 3403 << FixItHint::CreateInsertion(EndLoc, ".c_str()"); 3404 return true; 3405 } 3406 } 3407 3408 return false; 3409 } 3410 3411 bool 3412 CheckPrintfHandler::HandlePrintfSpecifier(const analyze_printf::PrintfSpecifier 3413 &FS, 3414 const char *startSpecifier, 3415 unsigned specifierLen) { 3416 3417 using namespace analyze_format_string; 3418 using namespace analyze_printf; 3419 const PrintfConversionSpecifier &CS = FS.getConversionSpecifier(); 3420 3421 if (FS.consumesDataArgument()) { 3422 if (atFirstArg) { 3423 atFirstArg = false; 3424 usesPositionalArgs = FS.usesPositionalArg(); 3425 } 3426 else if (usesPositionalArgs != FS.usesPositionalArg()) { 3427 HandlePositionalNonpositionalArgs(getLocationOfByte(CS.getStart()), 3428 startSpecifier, specifierLen); 3429 return false; 3430 } 3431 } 3432 3433 // First check if the field width, precision, and conversion specifier 3434 // have matching data arguments. 3435 if (!HandleAmount(FS.getFieldWidth(), /* field width */ 0, 3436 startSpecifier, specifierLen)) { 3437 return false; 3438 } 3439 3440 if (!HandleAmount(FS.getPrecision(), /* precision */ 1, 3441 startSpecifier, specifierLen)) { 3442 return false; 3443 } 3444 3445 if (!CS.consumesDataArgument()) { 3446 // FIXME: Technically specifying a precision or field width here 3447 // makes no sense. Worth issuing a warning at some point. 3448 return true; 3449 } 3450 3451 // Consume the argument. 3452 unsigned argIndex = FS.getArgIndex(); 3453 if (argIndex < NumDataArgs) { 3454 // The check to see if the argIndex is valid will come later. 3455 // We set the bit here because we may exit early from this 3456 // function if we encounter some other error. 3457 CoveredArgs.set(argIndex); 3458 } 3459 3460 // FreeBSD kernel extensions. 3461 if (CS.getKind() == ConversionSpecifier::FreeBSDbArg || 3462 CS.getKind() == ConversionSpecifier::FreeBSDDArg) { 3463 // We need at least two arguments. 3464 if (!CheckNumArgs(FS, CS, startSpecifier, specifierLen, argIndex + 1)) 3465 return false; 3466 3467 // Claim the second argument. 3468 CoveredArgs.set(argIndex + 1); 3469 3470 // Type check the first argument (int for %b, pointer for %D) 3471 const Expr *Ex = getDataArg(argIndex); 3472 const analyze_printf::ArgType &AT = 3473 (CS.getKind() == ConversionSpecifier::FreeBSDbArg) ? 3474 ArgType(S.Context.IntTy) : ArgType::CPointerTy; 3475 if (AT.isValid() && !AT.matchesType(S.Context, Ex->getType())) 3476 EmitFormatDiagnostic( 3477 S.PDiag(diag::warn_format_conversion_argument_type_mismatch) 3478 << AT.getRepresentativeTypeName(S.Context) << Ex->getType() 3479 << false << Ex->getSourceRange(), 3480 Ex->getLocStart(), /*IsStringLocation*/false, 3481 getSpecifierRange(startSpecifier, specifierLen)); 3482 3483 // Type check the second argument (char * for both %b and %D) 3484 Ex = getDataArg(argIndex + 1); 3485 const analyze_printf::ArgType &AT2 = ArgType::CStrTy; 3486 if (AT2.isValid() && !AT2.matchesType(S.Context, Ex->getType())) 3487 EmitFormatDiagnostic( 3488 S.PDiag(diag::warn_format_conversion_argument_type_mismatch) 3489 << AT2.getRepresentativeTypeName(S.Context) << Ex->getType() 3490 << false << Ex->getSourceRange(), 3491 Ex->getLocStart(), /*IsStringLocation*/false, 3492 getSpecifierRange(startSpecifier, specifierLen)); 3493 3494 return true; 3495 } 3496 3497 // Check for using an Objective-C specific conversion specifier 3498 // in a non-ObjC literal. 3499 if (!ObjCContext && CS.isObjCArg()) { 3500 return HandleInvalidPrintfConversionSpecifier(FS, startSpecifier, 3501 specifierLen); 3502 } 3503 3504 // Check for invalid use of field width 3505 if (!FS.hasValidFieldWidth()) { 3506 HandleInvalidAmount(FS, FS.getFieldWidth(), /* field width */ 0, 3507 startSpecifier, specifierLen); 3508 } 3509 3510 // Check for invalid use of precision 3511 if (!FS.hasValidPrecision()) { 3512 HandleInvalidAmount(FS, FS.getPrecision(), /* precision */ 1, 3513 startSpecifier, specifierLen); 3514 } 3515 3516 // Check each flag does not conflict with any other component. 3517 if (!FS.hasValidThousandsGroupingPrefix()) 3518 HandleFlag(FS, FS.hasThousandsGrouping(), startSpecifier, specifierLen); 3519 if (!FS.hasValidLeadingZeros()) 3520 HandleFlag(FS, FS.hasLeadingZeros(), startSpecifier, specifierLen); 3521 if (!FS.hasValidPlusPrefix()) 3522 HandleFlag(FS, FS.hasPlusPrefix(), startSpecifier, specifierLen); 3523 if (!FS.hasValidSpacePrefix()) 3524 HandleFlag(FS, FS.hasSpacePrefix(), startSpecifier, specifierLen); 3525 if (!FS.hasValidAlternativeForm()) 3526 HandleFlag(FS, FS.hasAlternativeForm(), startSpecifier, specifierLen); 3527 if (!FS.hasValidLeftJustified()) 3528 HandleFlag(FS, FS.isLeftJustified(), startSpecifier, specifierLen); 3529 3530 // Check that flags are not ignored by another flag 3531 if (FS.hasSpacePrefix() && FS.hasPlusPrefix()) // ' ' ignored by '+' 3532 HandleIgnoredFlag(FS, FS.hasSpacePrefix(), FS.hasPlusPrefix(), 3533 startSpecifier, specifierLen); 3534 if (FS.hasLeadingZeros() && FS.isLeftJustified()) // '0' ignored by '-' 3535 HandleIgnoredFlag(FS, FS.hasLeadingZeros(), FS.isLeftJustified(), 3536 startSpecifier, specifierLen); 3537 3538 // Check the length modifier is valid with the given conversion specifier. 3539 if (!FS.hasValidLengthModifier(S.getASTContext().getTargetInfo())) 3540 HandleInvalidLengthModifier(FS, CS, startSpecifier, specifierLen, 3541 diag::warn_format_nonsensical_length); 3542 else if (!FS.hasStandardLengthModifier()) 3543 HandleNonStandardLengthModifier(FS, startSpecifier, specifierLen); 3544 else if (!FS.hasStandardLengthConversionCombination()) 3545 HandleInvalidLengthModifier(FS, CS, startSpecifier, specifierLen, 3546 diag::warn_format_non_standard_conversion_spec); 3547 3548 if (!FS.hasStandardConversionSpecifier(S.getLangOpts())) 3549 HandleNonStandardConversionSpecifier(CS, startSpecifier, specifierLen); 3550 3551 // The remaining checks depend on the data arguments. 3552 if (HasVAListArg) 3553 return true; 3554 3555 if (!CheckNumArgs(FS, CS, startSpecifier, specifierLen, argIndex)) 3556 return false; 3557 3558 const Expr *Arg = getDataArg(argIndex); 3559 if (!Arg) 3560 return true; 3561 3562 return checkFormatExpr(FS, startSpecifier, specifierLen, Arg); 3563 } 3564 3565 static bool requiresParensToAddCast(const Expr *E) { 3566 // FIXME: We should have a general way to reason about operator 3567 // precedence and whether parens are actually needed here. 3568 // Take care of a few common cases where they aren't. 3569 const Expr *Inside = E->IgnoreImpCasts(); 3570 if (const PseudoObjectExpr *POE = dyn_cast<PseudoObjectExpr>(Inside)) 3571 Inside = POE->getSyntacticForm()->IgnoreImpCasts(); 3572 3573 switch (Inside->getStmtClass()) { 3574 case Stmt::ArraySubscriptExprClass: 3575 case Stmt::CallExprClass: 3576 case Stmt::CharacterLiteralClass: 3577 case Stmt::CXXBoolLiteralExprClass: 3578 case Stmt::DeclRefExprClass: 3579 case Stmt::FloatingLiteralClass: 3580 case Stmt::IntegerLiteralClass: 3581 case Stmt::MemberExprClass: 3582 case Stmt::ObjCArrayLiteralClass: 3583 case Stmt::ObjCBoolLiteralExprClass: 3584 case Stmt::ObjCBoxedExprClass: 3585 case Stmt::ObjCDictionaryLiteralClass: 3586 case Stmt::ObjCEncodeExprClass: 3587 case Stmt::ObjCIvarRefExprClass: 3588 case Stmt::ObjCMessageExprClass: 3589 case Stmt::ObjCPropertyRefExprClass: 3590 case Stmt::ObjCStringLiteralClass: 3591 case Stmt::ObjCSubscriptRefExprClass: 3592 case Stmt::ParenExprClass: 3593 case Stmt::StringLiteralClass: 3594 case Stmt::UnaryOperatorClass: 3595 return false; 3596 default: 3597 return true; 3598 } 3599 } 3600 3601 static std::pair<QualType, StringRef> 3602 shouldNotPrintDirectly(const ASTContext &Context, 3603 QualType IntendedTy, 3604 const Expr *E) { 3605 // Use a 'while' to peel off layers of typedefs. 3606 QualType TyTy = IntendedTy; 3607 while (const TypedefType *UserTy = TyTy->getAs<TypedefType>()) { 3608 StringRef Name = UserTy->getDecl()->getName(); 3609 QualType CastTy = llvm::StringSwitch<QualType>(Name) 3610 .Case("NSInteger", Context.LongTy) 3611 .Case("NSUInteger", Context.UnsignedLongTy) 3612 .Case("SInt32", Context.IntTy) 3613 .Case("UInt32", Context.UnsignedIntTy) 3614 .Default(QualType()); 3615 3616 if (!CastTy.isNull()) 3617 return std::make_pair(CastTy, Name); 3618 3619 TyTy = UserTy->desugar(); 3620 } 3621 3622 // Strip parens if necessary. 3623 if (const ParenExpr *PE = dyn_cast<ParenExpr>(E)) 3624 return shouldNotPrintDirectly(Context, 3625 PE->getSubExpr()->getType(), 3626 PE->getSubExpr()); 3627 3628 // If this is a conditional expression, then its result type is constructed 3629 // via usual arithmetic conversions and thus there might be no necessary 3630 // typedef sugar there. Recurse to operands to check for NSInteger & 3631 // Co. usage condition. 3632 if (const ConditionalOperator *CO = dyn_cast<ConditionalOperator>(E)) { 3633 QualType TrueTy, FalseTy; 3634 StringRef TrueName, FalseName; 3635 3636 std::tie(TrueTy, TrueName) = 3637 shouldNotPrintDirectly(Context, 3638 CO->getTrueExpr()->getType(), 3639 CO->getTrueExpr()); 3640 std::tie(FalseTy, FalseName) = 3641 shouldNotPrintDirectly(Context, 3642 CO->getFalseExpr()->getType(), 3643 CO->getFalseExpr()); 3644 3645 if (TrueTy == FalseTy) 3646 return std::make_pair(TrueTy, TrueName); 3647 else if (TrueTy.isNull()) 3648 return std::make_pair(FalseTy, FalseName); 3649 else if (FalseTy.isNull()) 3650 return std::make_pair(TrueTy, TrueName); 3651 } 3652 3653 return std::make_pair(QualType(), StringRef()); 3654 } 3655 3656 bool 3657 CheckPrintfHandler::checkFormatExpr(const analyze_printf::PrintfSpecifier &FS, 3658 const char *StartSpecifier, 3659 unsigned SpecifierLen, 3660 const Expr *E) { 3661 using namespace analyze_format_string; 3662 using namespace analyze_printf; 3663 // Now type check the data expression that matches the 3664 // format specifier. 3665 const analyze_printf::ArgType &AT = FS.getArgType(S.Context, 3666 ObjCContext); 3667 if (!AT.isValid()) 3668 return true; 3669 3670 QualType ExprTy = E->getType(); 3671 while (const TypeOfExprType *TET = dyn_cast<TypeOfExprType>(ExprTy)) { 3672 ExprTy = TET->getUnderlyingExpr()->getType(); 3673 } 3674 3675 if (AT.matchesType(S.Context, ExprTy)) 3676 return true; 3677 3678 // Look through argument promotions for our error message's reported type. 3679 // This includes the integral and floating promotions, but excludes array 3680 // and function pointer decay; seeing that an argument intended to be a 3681 // string has type 'char [6]' is probably more confusing than 'char *'. 3682 if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) { 3683 if (ICE->getCastKind() == CK_IntegralCast || 3684 ICE->getCastKind() == CK_FloatingCast) { 3685 E = ICE->getSubExpr(); 3686 ExprTy = E->getType(); 3687 3688 // Check if we didn't match because of an implicit cast from a 'char' 3689 // or 'short' to an 'int'. This is done because printf is a varargs 3690 // function. 3691 if (ICE->getType() == S.Context.IntTy || 3692 ICE->getType() == S.Context.UnsignedIntTy) { 3693 // All further checking is done on the subexpression. 3694 if (AT.matchesType(S.Context, ExprTy)) 3695 return true; 3696 } 3697 } 3698 } else if (const CharacterLiteral *CL = dyn_cast<CharacterLiteral>(E)) { 3699 // Special case for 'a', which has type 'int' in C. 3700 // Note, however, that we do /not/ want to treat multibyte constants like 3701 // 'MooV' as characters! This form is deprecated but still exists. 3702 if (ExprTy == S.Context.IntTy) 3703 if (llvm::isUIntN(S.Context.getCharWidth(), CL->getValue())) 3704 ExprTy = S.Context.CharTy; 3705 } 3706 3707 // Look through enums to their underlying type. 3708 bool IsEnum = false; 3709 if (auto EnumTy = ExprTy->getAs<EnumType>()) { 3710 ExprTy = EnumTy->getDecl()->getIntegerType(); 3711 IsEnum = true; 3712 } 3713 3714 // %C in an Objective-C context prints a unichar, not a wchar_t. 3715 // If the argument is an integer of some kind, believe the %C and suggest 3716 // a cast instead of changing the conversion specifier. 3717 QualType IntendedTy = ExprTy; 3718 if (ObjCContext && 3719 FS.getConversionSpecifier().getKind() == ConversionSpecifier::CArg) { 3720 if (ExprTy->isIntegralOrUnscopedEnumerationType() && 3721 !ExprTy->isCharType()) { 3722 // 'unichar' is defined as a typedef of unsigned short, but we should 3723 // prefer using the typedef if it is visible. 3724 IntendedTy = S.Context.UnsignedShortTy; 3725 3726 // While we are here, check if the value is an IntegerLiteral that happens 3727 // to be within the valid range. 3728 if (const IntegerLiteral *IL = dyn_cast<IntegerLiteral>(E)) { 3729 const llvm::APInt &V = IL->getValue(); 3730 if (V.getActiveBits() <= S.Context.getTypeSize(IntendedTy)) 3731 return true; 3732 } 3733 3734 LookupResult Result(S, &S.Context.Idents.get("unichar"), E->getLocStart(), 3735 Sema::LookupOrdinaryName); 3736 if (S.LookupName(Result, S.getCurScope())) { 3737 NamedDecl *ND = Result.getFoundDecl(); 3738 if (TypedefNameDecl *TD = dyn_cast<TypedefNameDecl>(ND)) 3739 if (TD->getUnderlyingType() == IntendedTy) 3740 IntendedTy = S.Context.getTypedefType(TD); 3741 } 3742 } 3743 } 3744 3745 // Special-case some of Darwin's platform-independence types by suggesting 3746 // casts to primitive types that are known to be large enough. 3747 bool ShouldNotPrintDirectly = false; StringRef CastTyName; 3748 if (S.Context.getTargetInfo().getTriple().isOSDarwin()) { 3749 QualType CastTy; 3750 std::tie(CastTy, CastTyName) = shouldNotPrintDirectly(S.Context, IntendedTy, E); 3751 if (!CastTy.isNull()) { 3752 IntendedTy = CastTy; 3753 ShouldNotPrintDirectly = true; 3754 } 3755 } 3756 3757 // We may be able to offer a FixItHint if it is a supported type. 3758 PrintfSpecifier fixedFS = FS; 3759 bool success = fixedFS.fixType(IntendedTy, S.getLangOpts(), 3760 S.Context, ObjCContext); 3761 3762 if (success) { 3763 // Get the fix string from the fixed format specifier 3764 SmallString<16> buf; 3765 llvm::raw_svector_ostream os(buf); 3766 fixedFS.toString(os); 3767 3768 CharSourceRange SpecRange = getSpecifierRange(StartSpecifier, SpecifierLen); 3769 3770 if (IntendedTy == ExprTy && !ShouldNotPrintDirectly) { 3771 // In this case, the specifier is wrong and should be changed to match 3772 // the argument. 3773 EmitFormatDiagnostic( 3774 S.PDiag(diag::warn_format_conversion_argument_type_mismatch) 3775 << AT.getRepresentativeTypeName(S.Context) << IntendedTy << IsEnum 3776 << E->getSourceRange(), 3777 E->getLocStart(), 3778 /*IsStringLocation*/false, 3779 SpecRange, 3780 FixItHint::CreateReplacement(SpecRange, os.str())); 3781 3782 } else { 3783 // The canonical type for formatting this value is different from the 3784 // actual type of the expression. (This occurs, for example, with Darwin's 3785 // NSInteger on 32-bit platforms, where it is typedef'd as 'int', but 3786 // should be printed as 'long' for 64-bit compatibility.) 3787 // Rather than emitting a normal format/argument mismatch, we want to 3788 // add a cast to the recommended type (and correct the format string 3789 // if necessary). 3790 SmallString<16> CastBuf; 3791 llvm::raw_svector_ostream CastFix(CastBuf); 3792 CastFix << "("; 3793 IntendedTy.print(CastFix, S.Context.getPrintingPolicy()); 3794 CastFix << ")"; 3795 3796 SmallVector<FixItHint,4> Hints; 3797 if (!AT.matchesType(S.Context, IntendedTy)) 3798 Hints.push_back(FixItHint::CreateReplacement(SpecRange, os.str())); 3799 3800 if (const CStyleCastExpr *CCast = dyn_cast<CStyleCastExpr>(E)) { 3801 // If there's already a cast present, just replace it. 3802 SourceRange CastRange(CCast->getLParenLoc(), CCast->getRParenLoc()); 3803 Hints.push_back(FixItHint::CreateReplacement(CastRange, CastFix.str())); 3804 3805 } else if (!requiresParensToAddCast(E)) { 3806 // If the expression has high enough precedence, 3807 // just write the C-style cast. 3808 Hints.push_back(FixItHint::CreateInsertion(E->getLocStart(), 3809 CastFix.str())); 3810 } else { 3811 // Otherwise, add parens around the expression as well as the cast. 3812 CastFix << "("; 3813 Hints.push_back(FixItHint::CreateInsertion(E->getLocStart(), 3814 CastFix.str())); 3815 3816 SourceLocation After = S.getLocForEndOfToken(E->getLocEnd()); 3817 Hints.push_back(FixItHint::CreateInsertion(After, ")")); 3818 } 3819 3820 if (ShouldNotPrintDirectly) { 3821 // The expression has a type that should not be printed directly. 3822 // We extract the name from the typedef because we don't want to show 3823 // the underlying type in the diagnostic. 3824 StringRef Name; 3825 if (const TypedefType *TypedefTy = dyn_cast<TypedefType>(ExprTy)) 3826 Name = TypedefTy->getDecl()->getName(); 3827 else 3828 Name = CastTyName; 3829 EmitFormatDiagnostic(S.PDiag(diag::warn_format_argument_needs_cast) 3830 << Name << IntendedTy << IsEnum 3831 << E->getSourceRange(), 3832 E->getLocStart(), /*IsStringLocation=*/false, 3833 SpecRange, Hints); 3834 } else { 3835 // In this case, the expression could be printed using a different 3836 // specifier, but we've decided that the specifier is probably correct 3837 // and we should cast instead. Just use the normal warning message. 3838 EmitFormatDiagnostic( 3839 S.PDiag(diag::warn_format_conversion_argument_type_mismatch) 3840 << AT.getRepresentativeTypeName(S.Context) << ExprTy << IsEnum 3841 << E->getSourceRange(), 3842 E->getLocStart(), /*IsStringLocation*/false, 3843 SpecRange, Hints); 3844 } 3845 } 3846 } else { 3847 const CharSourceRange &CSR = getSpecifierRange(StartSpecifier, 3848 SpecifierLen); 3849 // Since the warning for passing non-POD types to variadic functions 3850 // was deferred until now, we emit a warning for non-POD 3851 // arguments here. 3852 switch (S.isValidVarArgType(ExprTy)) { 3853 case Sema::VAK_Valid: 3854 case Sema::VAK_ValidInCXX11: 3855 EmitFormatDiagnostic( 3856 S.PDiag(diag::warn_format_conversion_argument_type_mismatch) 3857 << AT.getRepresentativeTypeName(S.Context) << ExprTy << IsEnum 3858 << CSR 3859 << E->getSourceRange(), 3860 E->getLocStart(), /*IsStringLocation*/false, CSR); 3861 break; 3862 3863 case Sema::VAK_Undefined: 3864 case Sema::VAK_MSVCUndefined: 3865 EmitFormatDiagnostic( 3866 S.PDiag(diag::warn_non_pod_vararg_with_format_string) 3867 << S.getLangOpts().CPlusPlus11 3868 << ExprTy 3869 << CallType 3870 << AT.getRepresentativeTypeName(S.Context) 3871 << CSR 3872 << E->getSourceRange(), 3873 E->getLocStart(), /*IsStringLocation*/false, CSR); 3874 checkForCStrMembers(AT, E); 3875 break; 3876 3877 case Sema::VAK_Invalid: 3878 if (ExprTy->isObjCObjectType()) 3879 EmitFormatDiagnostic( 3880 S.PDiag(diag::err_cannot_pass_objc_interface_to_vararg_format) 3881 << S.getLangOpts().CPlusPlus11 3882 << ExprTy 3883 << CallType 3884 << AT.getRepresentativeTypeName(S.Context) 3885 << CSR 3886 << E->getSourceRange(), 3887 E->getLocStart(), /*IsStringLocation*/false, CSR); 3888 else 3889 // FIXME: If this is an initializer list, suggest removing the braces 3890 // or inserting a cast to the target type. 3891 S.Diag(E->getLocStart(), diag::err_cannot_pass_to_vararg_format) 3892 << isa<InitListExpr>(E) << ExprTy << CallType 3893 << AT.getRepresentativeTypeName(S.Context) 3894 << E->getSourceRange(); 3895 break; 3896 } 3897 3898 assert(FirstDataArg + FS.getArgIndex() < CheckedVarArgs.size() && 3899 "format string specifier index out of range"); 3900 CheckedVarArgs[FirstDataArg + FS.getArgIndex()] = true; 3901 } 3902 3903 return true; 3904 } 3905 3906 //===--- CHECK: Scanf format string checking ------------------------------===// 3907 3908 namespace { 3909 class CheckScanfHandler : public CheckFormatHandler { 3910 public: 3911 CheckScanfHandler(Sema &s, const StringLiteral *fexpr, 3912 const Expr *origFormatExpr, unsigned firstDataArg, 3913 unsigned numDataArgs, const char *beg, bool hasVAListArg, 3914 ArrayRef<const Expr *> Args, 3915 unsigned formatIdx, bool inFunctionCall, 3916 Sema::VariadicCallType CallType, 3917 llvm::SmallBitVector &CheckedVarArgs) 3918 : CheckFormatHandler(s, fexpr, origFormatExpr, firstDataArg, 3919 numDataArgs, beg, hasVAListArg, 3920 Args, formatIdx, inFunctionCall, CallType, 3921 CheckedVarArgs) 3922 {} 3923 3924 bool HandleScanfSpecifier(const analyze_scanf::ScanfSpecifier &FS, 3925 const char *startSpecifier, 3926 unsigned specifierLen) override; 3927 3928 bool HandleInvalidScanfConversionSpecifier( 3929 const analyze_scanf::ScanfSpecifier &FS, 3930 const char *startSpecifier, 3931 unsigned specifierLen) override; 3932 3933 void HandleIncompleteScanList(const char *start, const char *end) override; 3934 }; 3935 } 3936 3937 void CheckScanfHandler::HandleIncompleteScanList(const char *start, 3938 const char *end) { 3939 EmitFormatDiagnostic(S.PDiag(diag::warn_scanf_scanlist_incomplete), 3940 getLocationOfByte(end), /*IsStringLocation*/true, 3941 getSpecifierRange(start, end - start)); 3942 } 3943 3944 bool CheckScanfHandler::HandleInvalidScanfConversionSpecifier( 3945 const analyze_scanf::ScanfSpecifier &FS, 3946 const char *startSpecifier, 3947 unsigned specifierLen) { 3948 3949 const analyze_scanf::ScanfConversionSpecifier &CS = 3950 FS.getConversionSpecifier(); 3951 3952 return HandleInvalidConversionSpecifier(FS.getArgIndex(), 3953 getLocationOfByte(CS.getStart()), 3954 startSpecifier, specifierLen, 3955 CS.getStart(), CS.getLength()); 3956 } 3957 3958 bool CheckScanfHandler::HandleScanfSpecifier( 3959 const analyze_scanf::ScanfSpecifier &FS, 3960 const char *startSpecifier, 3961 unsigned specifierLen) { 3962 3963 using namespace analyze_scanf; 3964 using namespace analyze_format_string; 3965 3966 const ScanfConversionSpecifier &CS = FS.getConversionSpecifier(); 3967 3968 // Handle case where '%' and '*' don't consume an argument. These shouldn't 3969 // be used to decide if we are using positional arguments consistently. 3970 if (FS.consumesDataArgument()) { 3971 if (atFirstArg) { 3972 atFirstArg = false; 3973 usesPositionalArgs = FS.usesPositionalArg(); 3974 } 3975 else if (usesPositionalArgs != FS.usesPositionalArg()) { 3976 HandlePositionalNonpositionalArgs(getLocationOfByte(CS.getStart()), 3977 startSpecifier, specifierLen); 3978 return false; 3979 } 3980 } 3981 3982 // Check if the field with is non-zero. 3983 const OptionalAmount &Amt = FS.getFieldWidth(); 3984 if (Amt.getHowSpecified() == OptionalAmount::Constant) { 3985 if (Amt.getConstantAmount() == 0) { 3986 const CharSourceRange &R = getSpecifierRange(Amt.getStart(), 3987 Amt.getConstantLength()); 3988 EmitFormatDiagnostic(S.PDiag(diag::warn_scanf_nonzero_width), 3989 getLocationOfByte(Amt.getStart()), 3990 /*IsStringLocation*/true, R, 3991 FixItHint::CreateRemoval(R)); 3992 } 3993 } 3994 3995 if (!FS.consumesDataArgument()) { 3996 // FIXME: Technically specifying a precision or field width here 3997 // makes no sense. Worth issuing a warning at some point. 3998 return true; 3999 } 4000 4001 // Consume the argument. 4002 unsigned argIndex = FS.getArgIndex(); 4003 if (argIndex < NumDataArgs) { 4004 // The check to see if the argIndex is valid will come later. 4005 // We set the bit here because we may exit early from this 4006 // function if we encounter some other error. 4007 CoveredArgs.set(argIndex); 4008 } 4009 4010 // Check the length modifier is valid with the given conversion specifier. 4011 if (!FS.hasValidLengthModifier(S.getASTContext().getTargetInfo())) 4012 HandleInvalidLengthModifier(FS, CS, startSpecifier, specifierLen, 4013 diag::warn_format_nonsensical_length); 4014 else if (!FS.hasStandardLengthModifier()) 4015 HandleNonStandardLengthModifier(FS, startSpecifier, specifierLen); 4016 else if (!FS.hasStandardLengthConversionCombination()) 4017 HandleInvalidLengthModifier(FS, CS, startSpecifier, specifierLen, 4018 diag::warn_format_non_standard_conversion_spec); 4019 4020 if (!FS.hasStandardConversionSpecifier(S.getLangOpts())) 4021 HandleNonStandardConversionSpecifier(CS, startSpecifier, specifierLen); 4022 4023 // The remaining checks depend on the data arguments. 4024 if (HasVAListArg) 4025 return true; 4026 4027 if (!CheckNumArgs(FS, CS, startSpecifier, specifierLen, argIndex)) 4028 return false; 4029 4030 // Check that the argument type matches the format specifier. 4031 const Expr *Ex = getDataArg(argIndex); 4032 if (!Ex) 4033 return true; 4034 4035 const analyze_format_string::ArgType &AT = FS.getArgType(S.Context); 4036 if (AT.isValid() && !AT.matchesType(S.Context, Ex->getType())) { 4037 ScanfSpecifier fixedFS = FS; 4038 bool success = fixedFS.fixType(Ex->getType(), 4039 Ex->IgnoreImpCasts()->getType(), 4040 S.getLangOpts(), S.Context); 4041 4042 if (success) { 4043 // Get the fix string from the fixed format specifier. 4044 SmallString<128> buf; 4045 llvm::raw_svector_ostream os(buf); 4046 fixedFS.toString(os); 4047 4048 EmitFormatDiagnostic( 4049 S.PDiag(diag::warn_format_conversion_argument_type_mismatch) 4050 << AT.getRepresentativeTypeName(S.Context) << Ex->getType() << false 4051 << Ex->getSourceRange(), 4052 Ex->getLocStart(), 4053 /*IsStringLocation*/false, 4054 getSpecifierRange(startSpecifier, specifierLen), 4055 FixItHint::CreateReplacement( 4056 getSpecifierRange(startSpecifier, specifierLen), 4057 os.str())); 4058 } else { 4059 EmitFormatDiagnostic( 4060 S.PDiag(diag::warn_format_conversion_argument_type_mismatch) 4061 << AT.getRepresentativeTypeName(S.Context) << Ex->getType() << false 4062 << Ex->getSourceRange(), 4063 Ex->getLocStart(), 4064 /*IsStringLocation*/false, 4065 getSpecifierRange(startSpecifier, specifierLen)); 4066 } 4067 } 4068 4069 return true; 4070 } 4071 4072 void Sema::CheckFormatString(const StringLiteral *FExpr, 4073 const Expr *OrigFormatExpr, 4074 ArrayRef<const Expr *> Args, 4075 bool HasVAListArg, unsigned format_idx, 4076 unsigned firstDataArg, FormatStringType Type, 4077 bool inFunctionCall, VariadicCallType CallType, 4078 llvm::SmallBitVector &CheckedVarArgs) { 4079 4080 // CHECK: is the format string a wide literal? 4081 if (!FExpr->isAscii() && !FExpr->isUTF8()) { 4082 CheckFormatHandler::EmitFormatDiagnostic( 4083 *this, inFunctionCall, Args[format_idx], 4084 PDiag(diag::warn_format_string_is_wide_literal), FExpr->getLocStart(), 4085 /*IsStringLocation*/true, OrigFormatExpr->getSourceRange()); 4086 return; 4087 } 4088 4089 // Str - The format string. NOTE: this is NOT null-terminated! 4090 StringRef StrRef = FExpr->getString(); 4091 const char *Str = StrRef.data(); 4092 // Account for cases where the string literal is truncated in a declaration. 4093 const ConstantArrayType *T = Context.getAsConstantArrayType(FExpr->getType()); 4094 assert(T && "String literal not of constant array type!"); 4095 size_t TypeSize = T->getSize().getZExtValue(); 4096 size_t StrLen = std::min(std::max(TypeSize, size_t(1)) - 1, StrRef.size()); 4097 const unsigned numDataArgs = Args.size() - firstDataArg; 4098 4099 // Emit a warning if the string literal is truncated and does not contain an 4100 // embedded null character. 4101 if (TypeSize <= StrRef.size() && 4102 StrRef.substr(0, TypeSize).find('\0') == StringRef::npos) { 4103 CheckFormatHandler::EmitFormatDiagnostic( 4104 *this, inFunctionCall, Args[format_idx], 4105 PDiag(diag::warn_printf_format_string_not_null_terminated), 4106 FExpr->getLocStart(), 4107 /*IsStringLocation=*/true, OrigFormatExpr->getSourceRange()); 4108 return; 4109 } 4110 4111 // CHECK: empty format string? 4112 if (StrLen == 0 && numDataArgs > 0) { 4113 CheckFormatHandler::EmitFormatDiagnostic( 4114 *this, inFunctionCall, Args[format_idx], 4115 PDiag(diag::warn_empty_format_string), FExpr->getLocStart(), 4116 /*IsStringLocation*/true, OrigFormatExpr->getSourceRange()); 4117 return; 4118 } 4119 4120 if (Type == FST_Printf || Type == FST_NSString || 4121 Type == FST_FreeBSDKPrintf || Type == FST_OSTrace) { 4122 CheckPrintfHandler H(*this, FExpr, OrigFormatExpr, firstDataArg, 4123 numDataArgs, (Type == FST_NSString || Type == FST_OSTrace), 4124 Str, HasVAListArg, Args, format_idx, 4125 inFunctionCall, CallType, CheckedVarArgs); 4126 4127 if (!analyze_format_string::ParsePrintfString(H, Str, Str + StrLen, 4128 getLangOpts(), 4129 Context.getTargetInfo(), 4130 Type == FST_FreeBSDKPrintf)) 4131 H.DoneProcessing(); 4132 } else if (Type == FST_Scanf) { 4133 CheckScanfHandler H(*this, FExpr, OrigFormatExpr, firstDataArg, numDataArgs, 4134 Str, HasVAListArg, Args, format_idx, 4135 inFunctionCall, CallType, CheckedVarArgs); 4136 4137 if (!analyze_format_string::ParseScanfString(H, Str, Str + StrLen, 4138 getLangOpts(), 4139 Context.getTargetInfo())) 4140 H.DoneProcessing(); 4141 } // TODO: handle other formats 4142 } 4143 4144 bool Sema::FormatStringHasSArg(const StringLiteral *FExpr) { 4145 // Str - The format string. NOTE: this is NOT null-terminated! 4146 StringRef StrRef = FExpr->getString(); 4147 const char *Str = StrRef.data(); 4148 // Account for cases where the string literal is truncated in a declaration. 4149 const ConstantArrayType *T = Context.getAsConstantArrayType(FExpr->getType()); 4150 assert(T && "String literal not of constant array type!"); 4151 size_t TypeSize = T->getSize().getZExtValue(); 4152 size_t StrLen = std::min(std::max(TypeSize, size_t(1)) - 1, StrRef.size()); 4153 return analyze_format_string::ParseFormatStringHasSArg(Str, Str + StrLen, 4154 getLangOpts(), 4155 Context.getTargetInfo()); 4156 } 4157 4158 //===--- CHECK: Warn on use of wrong absolute value function. -------------===// 4159 4160 // Returns the related absolute value function that is larger, of 0 if one 4161 // does not exist. 4162 static unsigned getLargerAbsoluteValueFunction(unsigned AbsFunction) { 4163 switch (AbsFunction) { 4164 default: 4165 return 0; 4166 4167 case Builtin::BI__builtin_abs: 4168 return Builtin::BI__builtin_labs; 4169 case Builtin::BI__builtin_labs: 4170 return Builtin::BI__builtin_llabs; 4171 case Builtin::BI__builtin_llabs: 4172 return 0; 4173 4174 case Builtin::BI__builtin_fabsf: 4175 return Builtin::BI__builtin_fabs; 4176 case Builtin::BI__builtin_fabs: 4177 return Builtin::BI__builtin_fabsl; 4178 case Builtin::BI__builtin_fabsl: 4179 return 0; 4180 4181 case Builtin::BI__builtin_cabsf: 4182 return Builtin::BI__builtin_cabs; 4183 case Builtin::BI__builtin_cabs: 4184 return Builtin::BI__builtin_cabsl; 4185 case Builtin::BI__builtin_cabsl: 4186 return 0; 4187 4188 case Builtin::BIabs: 4189 return Builtin::BIlabs; 4190 case Builtin::BIlabs: 4191 return Builtin::BIllabs; 4192 case Builtin::BIllabs: 4193 return 0; 4194 4195 case Builtin::BIfabsf: 4196 return Builtin::BIfabs; 4197 case Builtin::BIfabs: 4198 return Builtin::BIfabsl; 4199 case Builtin::BIfabsl: 4200 return 0; 4201 4202 case Builtin::BIcabsf: 4203 return Builtin::BIcabs; 4204 case Builtin::BIcabs: 4205 return Builtin::BIcabsl; 4206 case Builtin::BIcabsl: 4207 return 0; 4208 } 4209 } 4210 4211 // Returns the argument type of the absolute value function. 4212 static QualType getAbsoluteValueArgumentType(ASTContext &Context, 4213 unsigned AbsType) { 4214 if (AbsType == 0) 4215 return QualType(); 4216 4217 ASTContext::GetBuiltinTypeError Error = ASTContext::GE_None; 4218 QualType BuiltinType = Context.GetBuiltinType(AbsType, Error); 4219 if (Error != ASTContext::GE_None) 4220 return QualType(); 4221 4222 const FunctionProtoType *FT = BuiltinType->getAs<FunctionProtoType>(); 4223 if (!FT) 4224 return QualType(); 4225 4226 if (FT->getNumParams() != 1) 4227 return QualType(); 4228 4229 return FT->getParamType(0); 4230 } 4231 4232 // Returns the best absolute value function, or zero, based on type and 4233 // current absolute value function. 4234 static unsigned getBestAbsFunction(ASTContext &Context, QualType ArgType, 4235 unsigned AbsFunctionKind) { 4236 unsigned BestKind = 0; 4237 uint64_t ArgSize = Context.getTypeSize(ArgType); 4238 for (unsigned Kind = AbsFunctionKind; Kind != 0; 4239 Kind = getLargerAbsoluteValueFunction(Kind)) { 4240 QualType ParamType = getAbsoluteValueArgumentType(Context, Kind); 4241 if (Context.getTypeSize(ParamType) >= ArgSize) { 4242 if (BestKind == 0) 4243 BestKind = Kind; 4244 else if (Context.hasSameType(ParamType, ArgType)) { 4245 BestKind = Kind; 4246 break; 4247 } 4248 } 4249 } 4250 return BestKind; 4251 } 4252 4253 enum AbsoluteValueKind { 4254 AVK_Integer, 4255 AVK_Floating, 4256 AVK_Complex 4257 }; 4258 4259 static AbsoluteValueKind getAbsoluteValueKind(QualType T) { 4260 if (T->isIntegralOrEnumerationType()) 4261 return AVK_Integer; 4262 if (T->isRealFloatingType()) 4263 return AVK_Floating; 4264 if (T->isAnyComplexType()) 4265 return AVK_Complex; 4266 4267 llvm_unreachable("Type not integer, floating, or complex"); 4268 } 4269 4270 // Changes the absolute value function to a different type. Preserves whether 4271 // the function is a builtin. 4272 static unsigned changeAbsFunction(unsigned AbsKind, 4273 AbsoluteValueKind ValueKind) { 4274 switch (ValueKind) { 4275 case AVK_Integer: 4276 switch (AbsKind) { 4277 default: 4278 return 0; 4279 case Builtin::BI__builtin_fabsf: 4280 case Builtin::BI__builtin_fabs: 4281 case Builtin::BI__builtin_fabsl: 4282 case Builtin::BI__builtin_cabsf: 4283 case Builtin::BI__builtin_cabs: 4284 case Builtin::BI__builtin_cabsl: 4285 return Builtin::BI__builtin_abs; 4286 case Builtin::BIfabsf: 4287 case Builtin::BIfabs: 4288 case Builtin::BIfabsl: 4289 case Builtin::BIcabsf: 4290 case Builtin::BIcabs: 4291 case Builtin::BIcabsl: 4292 return Builtin::BIabs; 4293 } 4294 case AVK_Floating: 4295 switch (AbsKind) { 4296 default: 4297 return 0; 4298 case Builtin::BI__builtin_abs: 4299 case Builtin::BI__builtin_labs: 4300 case Builtin::BI__builtin_llabs: 4301 case Builtin::BI__builtin_cabsf: 4302 case Builtin::BI__builtin_cabs: 4303 case Builtin::BI__builtin_cabsl: 4304 return Builtin::BI__builtin_fabsf; 4305 case Builtin::BIabs: 4306 case Builtin::BIlabs: 4307 case Builtin::BIllabs: 4308 case Builtin::BIcabsf: 4309 case Builtin::BIcabs: 4310 case Builtin::BIcabsl: 4311 return Builtin::BIfabsf; 4312 } 4313 case AVK_Complex: 4314 switch (AbsKind) { 4315 default: 4316 return 0; 4317 case Builtin::BI__builtin_abs: 4318 case Builtin::BI__builtin_labs: 4319 case Builtin::BI__builtin_llabs: 4320 case Builtin::BI__builtin_fabsf: 4321 case Builtin::BI__builtin_fabs: 4322 case Builtin::BI__builtin_fabsl: 4323 return Builtin::BI__builtin_cabsf; 4324 case Builtin::BIabs: 4325 case Builtin::BIlabs: 4326 case Builtin::BIllabs: 4327 case Builtin::BIfabsf: 4328 case Builtin::BIfabs: 4329 case Builtin::BIfabsl: 4330 return Builtin::BIcabsf; 4331 } 4332 } 4333 llvm_unreachable("Unable to convert function"); 4334 } 4335 4336 static unsigned getAbsoluteValueFunctionKind(const FunctionDecl *FDecl) { 4337 const IdentifierInfo *FnInfo = FDecl->getIdentifier(); 4338 if (!FnInfo) 4339 return 0; 4340 4341 switch (FDecl->getBuiltinID()) { 4342 default: 4343 return 0; 4344 case Builtin::BI__builtin_abs: 4345 case Builtin::BI__builtin_fabs: 4346 case Builtin::BI__builtin_fabsf: 4347 case Builtin::BI__builtin_fabsl: 4348 case Builtin::BI__builtin_labs: 4349 case Builtin::BI__builtin_llabs: 4350 case Builtin::BI__builtin_cabs: 4351 case Builtin::BI__builtin_cabsf: 4352 case Builtin::BI__builtin_cabsl: 4353 case Builtin::BIabs: 4354 case Builtin::BIlabs: 4355 case Builtin::BIllabs: 4356 case Builtin::BIfabs: 4357 case Builtin::BIfabsf: 4358 case Builtin::BIfabsl: 4359 case Builtin::BIcabs: 4360 case Builtin::BIcabsf: 4361 case Builtin::BIcabsl: 4362 return FDecl->getBuiltinID(); 4363 } 4364 llvm_unreachable("Unknown Builtin type"); 4365 } 4366 4367 // If the replacement is valid, emit a note with replacement function. 4368 // Additionally, suggest including the proper header if not already included. 4369 static void emitReplacement(Sema &S, SourceLocation Loc, SourceRange Range, 4370 unsigned AbsKind, QualType ArgType) { 4371 bool EmitHeaderHint = true; 4372 const char *HeaderName = nullptr; 4373 const char *FunctionName = nullptr; 4374 if (S.getLangOpts().CPlusPlus && !ArgType->isAnyComplexType()) { 4375 FunctionName = "std::abs"; 4376 if (ArgType->isIntegralOrEnumerationType()) { 4377 HeaderName = "cstdlib"; 4378 } else if (ArgType->isRealFloatingType()) { 4379 HeaderName = "cmath"; 4380 } else { 4381 llvm_unreachable("Invalid Type"); 4382 } 4383 4384 // Lookup all std::abs 4385 if (NamespaceDecl *Std = S.getStdNamespace()) { 4386 LookupResult R(S, &S.Context.Idents.get("abs"), Loc, Sema::LookupAnyName); 4387 R.suppressDiagnostics(); 4388 S.LookupQualifiedName(R, Std); 4389 4390 for (const auto *I : R) { 4391 const FunctionDecl *FDecl = nullptr; 4392 if (const UsingShadowDecl *UsingD = dyn_cast<UsingShadowDecl>(I)) { 4393 FDecl = dyn_cast<FunctionDecl>(UsingD->getTargetDecl()); 4394 } else { 4395 FDecl = dyn_cast<FunctionDecl>(I); 4396 } 4397 if (!FDecl) 4398 continue; 4399 4400 // Found std::abs(), check that they are the right ones. 4401 if (FDecl->getNumParams() != 1) 4402 continue; 4403 4404 // Check that the parameter type can handle the argument. 4405 QualType ParamType = FDecl->getParamDecl(0)->getType(); 4406 if (getAbsoluteValueKind(ArgType) == getAbsoluteValueKind(ParamType) && 4407 S.Context.getTypeSize(ArgType) <= 4408 S.Context.getTypeSize(ParamType)) { 4409 // Found a function, don't need the header hint. 4410 EmitHeaderHint = false; 4411 break; 4412 } 4413 } 4414 } 4415 } else { 4416 FunctionName = S.Context.BuiltinInfo.GetName(AbsKind); 4417 HeaderName = S.Context.BuiltinInfo.getHeaderName(AbsKind); 4418 4419 if (HeaderName) { 4420 DeclarationName DN(&S.Context.Idents.get(FunctionName)); 4421 LookupResult R(S, DN, Loc, Sema::LookupAnyName); 4422 R.suppressDiagnostics(); 4423 S.LookupName(R, S.getCurScope()); 4424 4425 if (R.isSingleResult()) { 4426 FunctionDecl *FD = dyn_cast<FunctionDecl>(R.getFoundDecl()); 4427 if (FD && FD->getBuiltinID() == AbsKind) { 4428 EmitHeaderHint = false; 4429 } else { 4430 return; 4431 } 4432 } else if (!R.empty()) { 4433 return; 4434 } 4435 } 4436 } 4437 4438 S.Diag(Loc, diag::note_replace_abs_function) 4439 << FunctionName << FixItHint::CreateReplacement(Range, FunctionName); 4440 4441 if (!HeaderName) 4442 return; 4443 4444 if (!EmitHeaderHint) 4445 return; 4446 4447 S.Diag(Loc, diag::note_include_header_or_declare) << HeaderName 4448 << FunctionName; 4449 } 4450 4451 static bool IsFunctionStdAbs(const FunctionDecl *FDecl) { 4452 if (!FDecl) 4453 return false; 4454 4455 if (!FDecl->getIdentifier() || !FDecl->getIdentifier()->isStr("abs")) 4456 return false; 4457 4458 const NamespaceDecl *ND = dyn_cast<NamespaceDecl>(FDecl->getDeclContext()); 4459 4460 while (ND && ND->isInlineNamespace()) { 4461 ND = dyn_cast<NamespaceDecl>(ND->getDeclContext()); 4462 } 4463 4464 if (!ND || !ND->getIdentifier() || !ND->getIdentifier()->isStr("std")) 4465 return false; 4466 4467 if (!isa<TranslationUnitDecl>(ND->getDeclContext())) 4468 return false; 4469 4470 return true; 4471 } 4472 4473 // Warn when using the wrong abs() function. 4474 void Sema::CheckAbsoluteValueFunction(const CallExpr *Call, 4475 const FunctionDecl *FDecl, 4476 IdentifierInfo *FnInfo) { 4477 if (Call->getNumArgs() != 1) 4478 return; 4479 4480 unsigned AbsKind = getAbsoluteValueFunctionKind(FDecl); 4481 bool IsStdAbs = IsFunctionStdAbs(FDecl); 4482 if (AbsKind == 0 && !IsStdAbs) 4483 return; 4484 4485 QualType ArgType = Call->getArg(0)->IgnoreParenImpCasts()->getType(); 4486 QualType ParamType = Call->getArg(0)->getType(); 4487 4488 // Unsigned types cannot be negative. Suggest removing the absolute value 4489 // function call. 4490 if (ArgType->isUnsignedIntegerType()) { 4491 const char *FunctionName = 4492 IsStdAbs ? "std::abs" : Context.BuiltinInfo.GetName(AbsKind); 4493 Diag(Call->getExprLoc(), diag::warn_unsigned_abs) << ArgType << ParamType; 4494 Diag(Call->getExprLoc(), diag::note_remove_abs) 4495 << FunctionName 4496 << FixItHint::CreateRemoval(Call->getCallee()->getSourceRange()); 4497 return; 4498 } 4499 4500 // std::abs has overloads which prevent most of the absolute value problems 4501 // from occurring. 4502 if (IsStdAbs) 4503 return; 4504 4505 AbsoluteValueKind ArgValueKind = getAbsoluteValueKind(ArgType); 4506 AbsoluteValueKind ParamValueKind = getAbsoluteValueKind(ParamType); 4507 4508 // The argument and parameter are the same kind. Check if they are the right 4509 // size. 4510 if (ArgValueKind == ParamValueKind) { 4511 if (Context.getTypeSize(ArgType) <= Context.getTypeSize(ParamType)) 4512 return; 4513 4514 unsigned NewAbsKind = getBestAbsFunction(Context, ArgType, AbsKind); 4515 Diag(Call->getExprLoc(), diag::warn_abs_too_small) 4516 << FDecl << ArgType << ParamType; 4517 4518 if (NewAbsKind == 0) 4519 return; 4520 4521 emitReplacement(*this, Call->getExprLoc(), 4522 Call->getCallee()->getSourceRange(), NewAbsKind, ArgType); 4523 return; 4524 } 4525 4526 // ArgValueKind != ParamValueKind 4527 // The wrong type of absolute value function was used. Attempt to find the 4528 // proper one. 4529 unsigned NewAbsKind = changeAbsFunction(AbsKind, ArgValueKind); 4530 NewAbsKind = getBestAbsFunction(Context, ArgType, NewAbsKind); 4531 if (NewAbsKind == 0) 4532 return; 4533 4534 Diag(Call->getExprLoc(), diag::warn_wrong_absolute_value_type) 4535 << FDecl << ParamValueKind << ArgValueKind; 4536 4537 emitReplacement(*this, Call->getExprLoc(), 4538 Call->getCallee()->getSourceRange(), NewAbsKind, ArgType); 4539 return; 4540 } 4541 4542 //===--- CHECK: Standard memory functions ---------------------------------===// 4543 4544 /// \brief Takes the expression passed to the size_t parameter of functions 4545 /// such as memcmp, strncat, etc and warns if it's a comparison. 4546 /// 4547 /// This is to catch typos like `if (memcmp(&a, &b, sizeof(a) > 0))`. 4548 static bool CheckMemorySizeofForComparison(Sema &S, const Expr *E, 4549 IdentifierInfo *FnName, 4550 SourceLocation FnLoc, 4551 SourceLocation RParenLoc) { 4552 const BinaryOperator *Size = dyn_cast<BinaryOperator>(E); 4553 if (!Size) 4554 return false; 4555 4556 // if E is binop and op is >, <, >=, <=, ==, &&, ||: 4557 if (!Size->isComparisonOp() && !Size->isEqualityOp() && !Size->isLogicalOp()) 4558 return false; 4559 4560 SourceRange SizeRange = Size->getSourceRange(); 4561 S.Diag(Size->getOperatorLoc(), diag::warn_memsize_comparison) 4562 << SizeRange << FnName; 4563 S.Diag(FnLoc, diag::note_memsize_comparison_paren) 4564 << FnName << FixItHint::CreateInsertion( 4565 S.getLocForEndOfToken(Size->getLHS()->getLocEnd()), ")") 4566 << FixItHint::CreateRemoval(RParenLoc); 4567 S.Diag(SizeRange.getBegin(), diag::note_memsize_comparison_cast_silence) 4568 << FixItHint::CreateInsertion(SizeRange.getBegin(), "(size_t)(") 4569 << FixItHint::CreateInsertion(S.getLocForEndOfToken(SizeRange.getEnd()), 4570 ")"); 4571 4572 return true; 4573 } 4574 4575 /// \brief Determine whether the given type is or contains a dynamic class type 4576 /// (e.g., whether it has a vtable). 4577 static const CXXRecordDecl *getContainedDynamicClass(QualType T, 4578 bool &IsContained) { 4579 // Look through array types while ignoring qualifiers. 4580 const Type *Ty = T->getBaseElementTypeUnsafe(); 4581 IsContained = false; 4582 4583 const CXXRecordDecl *RD = Ty->getAsCXXRecordDecl(); 4584 RD = RD ? RD->getDefinition() : nullptr; 4585 if (!RD) 4586 return nullptr; 4587 4588 if (RD->isDynamicClass()) 4589 return RD; 4590 4591 // Check all the fields. If any bases were dynamic, the class is dynamic. 4592 // It's impossible for a class to transitively contain itself by value, so 4593 // infinite recursion is impossible. 4594 for (auto *FD : RD->fields()) { 4595 bool SubContained; 4596 if (const CXXRecordDecl *ContainedRD = 4597 getContainedDynamicClass(FD->getType(), SubContained)) { 4598 IsContained = true; 4599 return ContainedRD; 4600 } 4601 } 4602 4603 return nullptr; 4604 } 4605 4606 /// \brief If E is a sizeof expression, returns its argument expression, 4607 /// otherwise returns NULL. 4608 static const Expr *getSizeOfExprArg(const Expr* E) { 4609 if (const UnaryExprOrTypeTraitExpr *SizeOf = 4610 dyn_cast<UnaryExprOrTypeTraitExpr>(E)) 4611 if (SizeOf->getKind() == clang::UETT_SizeOf && !SizeOf->isArgumentType()) 4612 return SizeOf->getArgumentExpr()->IgnoreParenImpCasts(); 4613 4614 return nullptr; 4615 } 4616 4617 /// \brief If E is a sizeof expression, returns its argument type. 4618 static QualType getSizeOfArgType(const Expr* E) { 4619 if (const UnaryExprOrTypeTraitExpr *SizeOf = 4620 dyn_cast<UnaryExprOrTypeTraitExpr>(E)) 4621 if (SizeOf->getKind() == clang::UETT_SizeOf) 4622 return SizeOf->getTypeOfArgument(); 4623 4624 return QualType(); 4625 } 4626 4627 /// \brief Check for dangerous or invalid arguments to memset(). 4628 /// 4629 /// This issues warnings on known problematic, dangerous or unspecified 4630 /// arguments to the standard 'memset', 'memcpy', 'memmove', and 'memcmp' 4631 /// function calls. 4632 /// 4633 /// \param Call The call expression to diagnose. 4634 void Sema::CheckMemaccessArguments(const CallExpr *Call, 4635 unsigned BId, 4636 IdentifierInfo *FnName) { 4637 assert(BId != 0); 4638 4639 // It is possible to have a non-standard definition of memset. Validate 4640 // we have enough arguments, and if not, abort further checking. 4641 unsigned ExpectedNumArgs = (BId == Builtin::BIstrndup ? 2 : 3); 4642 if (Call->getNumArgs() < ExpectedNumArgs) 4643 return; 4644 4645 unsigned LastArg = (BId == Builtin::BImemset || 4646 BId == Builtin::BIstrndup ? 1 : 2); 4647 unsigned LenArg = (BId == Builtin::BIstrndup ? 1 : 2); 4648 const Expr *LenExpr = Call->getArg(LenArg)->IgnoreParenImpCasts(); 4649 4650 if (CheckMemorySizeofForComparison(*this, LenExpr, FnName, 4651 Call->getLocStart(), Call->getRParenLoc())) 4652 return; 4653 4654 // We have special checking when the length is a sizeof expression. 4655 QualType SizeOfArgTy = getSizeOfArgType(LenExpr); 4656 const Expr *SizeOfArg = getSizeOfExprArg(LenExpr); 4657 llvm::FoldingSetNodeID SizeOfArgID; 4658 4659 for (unsigned ArgIdx = 0; ArgIdx != LastArg; ++ArgIdx) { 4660 const Expr *Dest = Call->getArg(ArgIdx)->IgnoreParenImpCasts(); 4661 SourceRange ArgRange = Call->getArg(ArgIdx)->getSourceRange(); 4662 4663 QualType DestTy = Dest->getType(); 4664 if (const PointerType *DestPtrTy = DestTy->getAs<PointerType>()) { 4665 QualType PointeeTy = DestPtrTy->getPointeeType(); 4666 4667 // Never warn about void type pointers. This can be used to suppress 4668 // false positives. 4669 if (PointeeTy->isVoidType()) 4670 continue; 4671 4672 // Catch "memset(p, 0, sizeof(p))" -- needs to be sizeof(*p). Do this by 4673 // actually comparing the expressions for equality. Because computing the 4674 // expression IDs can be expensive, we only do this if the diagnostic is 4675 // enabled. 4676 if (SizeOfArg && 4677 !Diags.isIgnored(diag::warn_sizeof_pointer_expr_memaccess, 4678 SizeOfArg->getExprLoc())) { 4679 // We only compute IDs for expressions if the warning is enabled, and 4680 // cache the sizeof arg's ID. 4681 if (SizeOfArgID == llvm::FoldingSetNodeID()) 4682 SizeOfArg->Profile(SizeOfArgID, Context, true); 4683 llvm::FoldingSetNodeID DestID; 4684 Dest->Profile(DestID, Context, true); 4685 if (DestID == SizeOfArgID) { 4686 // TODO: For strncpy() and friends, this could suggest sizeof(dst) 4687 // over sizeof(src) as well. 4688 unsigned ActionIdx = 0; // Default is to suggest dereferencing. 4689 StringRef ReadableName = FnName->getName(); 4690 4691 if (const UnaryOperator *UnaryOp = dyn_cast<UnaryOperator>(Dest)) 4692 if (UnaryOp->getOpcode() == UO_AddrOf) 4693 ActionIdx = 1; // If its an address-of operator, just remove it. 4694 if (!PointeeTy->isIncompleteType() && 4695 (Context.getTypeSize(PointeeTy) == Context.getCharWidth())) 4696 ActionIdx = 2; // If the pointee's size is sizeof(char), 4697 // suggest an explicit length. 4698 4699 // If the function is defined as a builtin macro, do not show macro 4700 // expansion. 4701 SourceLocation SL = SizeOfArg->getExprLoc(); 4702 SourceRange DSR = Dest->getSourceRange(); 4703 SourceRange SSR = SizeOfArg->getSourceRange(); 4704 SourceManager &SM = getSourceManager(); 4705 4706 if (SM.isMacroArgExpansion(SL)) { 4707 ReadableName = Lexer::getImmediateMacroName(SL, SM, LangOpts); 4708 SL = SM.getSpellingLoc(SL); 4709 DSR = SourceRange(SM.getSpellingLoc(DSR.getBegin()), 4710 SM.getSpellingLoc(DSR.getEnd())); 4711 SSR = SourceRange(SM.getSpellingLoc(SSR.getBegin()), 4712 SM.getSpellingLoc(SSR.getEnd())); 4713 } 4714 4715 DiagRuntimeBehavior(SL, SizeOfArg, 4716 PDiag(diag::warn_sizeof_pointer_expr_memaccess) 4717 << ReadableName 4718 << PointeeTy 4719 << DestTy 4720 << DSR 4721 << SSR); 4722 DiagRuntimeBehavior(SL, SizeOfArg, 4723 PDiag(diag::warn_sizeof_pointer_expr_memaccess_note) 4724 << ActionIdx 4725 << SSR); 4726 4727 break; 4728 } 4729 } 4730 4731 // Also check for cases where the sizeof argument is the exact same 4732 // type as the memory argument, and where it points to a user-defined 4733 // record type. 4734 if (SizeOfArgTy != QualType()) { 4735 if (PointeeTy->isRecordType() && 4736 Context.typesAreCompatible(SizeOfArgTy, DestTy)) { 4737 DiagRuntimeBehavior(LenExpr->getExprLoc(), Dest, 4738 PDiag(diag::warn_sizeof_pointer_type_memaccess) 4739 << FnName << SizeOfArgTy << ArgIdx 4740 << PointeeTy << Dest->getSourceRange() 4741 << LenExpr->getSourceRange()); 4742 break; 4743 } 4744 } 4745 4746 // Always complain about dynamic classes. 4747 bool IsContained; 4748 if (const CXXRecordDecl *ContainedRD = 4749 getContainedDynamicClass(PointeeTy, IsContained)) { 4750 4751 unsigned OperationType = 0; 4752 // "overwritten" if we're warning about the destination for any call 4753 // but memcmp; otherwise a verb appropriate to the call. 4754 if (ArgIdx != 0 || BId == Builtin::BImemcmp) { 4755 if (BId == Builtin::BImemcpy) 4756 OperationType = 1; 4757 else if(BId == Builtin::BImemmove) 4758 OperationType = 2; 4759 else if (BId == Builtin::BImemcmp) 4760 OperationType = 3; 4761 } 4762 4763 DiagRuntimeBehavior( 4764 Dest->getExprLoc(), Dest, 4765 PDiag(diag::warn_dyn_class_memaccess) 4766 << (BId == Builtin::BImemcmp ? ArgIdx + 2 : ArgIdx) 4767 << FnName << IsContained << ContainedRD << OperationType 4768 << Call->getCallee()->getSourceRange()); 4769 } else if (PointeeTy.hasNonTrivialObjCLifetime() && 4770 BId != Builtin::BImemset) 4771 DiagRuntimeBehavior( 4772 Dest->getExprLoc(), Dest, 4773 PDiag(diag::warn_arc_object_memaccess) 4774 << ArgIdx << FnName << PointeeTy 4775 << Call->getCallee()->getSourceRange()); 4776 else 4777 continue; 4778 4779 DiagRuntimeBehavior( 4780 Dest->getExprLoc(), Dest, 4781 PDiag(diag::note_bad_memaccess_silence) 4782 << FixItHint::CreateInsertion(ArgRange.getBegin(), "(void*)")); 4783 break; 4784 } 4785 } 4786 } 4787 4788 // A little helper routine: ignore addition and subtraction of integer literals. 4789 // This intentionally does not ignore all integer constant expressions because 4790 // we don't want to remove sizeof(). 4791 static const Expr *ignoreLiteralAdditions(const Expr *Ex, ASTContext &Ctx) { 4792 Ex = Ex->IgnoreParenCasts(); 4793 4794 for (;;) { 4795 const BinaryOperator * BO = dyn_cast<BinaryOperator>(Ex); 4796 if (!BO || !BO->isAdditiveOp()) 4797 break; 4798 4799 const Expr *RHS = BO->getRHS()->IgnoreParenCasts(); 4800 const Expr *LHS = BO->getLHS()->IgnoreParenCasts(); 4801 4802 if (isa<IntegerLiteral>(RHS)) 4803 Ex = LHS; 4804 else if (isa<IntegerLiteral>(LHS)) 4805 Ex = RHS; 4806 else 4807 break; 4808 } 4809 4810 return Ex; 4811 } 4812 4813 static bool isConstantSizeArrayWithMoreThanOneElement(QualType Ty, 4814 ASTContext &Context) { 4815 // Only handle constant-sized or VLAs, but not flexible members. 4816 if (const ConstantArrayType *CAT = Context.getAsConstantArrayType(Ty)) { 4817 // Only issue the FIXIT for arrays of size > 1. 4818 if (CAT->getSize().getSExtValue() <= 1) 4819 return false; 4820 } else if (!Ty->isVariableArrayType()) { 4821 return false; 4822 } 4823 return true; 4824 } 4825 4826 // Warn if the user has made the 'size' argument to strlcpy or strlcat 4827 // be the size of the source, instead of the destination. 4828 void Sema::CheckStrlcpycatArguments(const CallExpr *Call, 4829 IdentifierInfo *FnName) { 4830 4831 // Don't crash if the user has the wrong number of arguments 4832 unsigned NumArgs = Call->getNumArgs(); 4833 if ((NumArgs != 3) && (NumArgs != 4)) 4834 return; 4835 4836 const Expr *SrcArg = ignoreLiteralAdditions(Call->getArg(1), Context); 4837 const Expr *SizeArg = ignoreLiteralAdditions(Call->getArg(2), Context); 4838 const Expr *CompareWithSrc = nullptr; 4839 4840 if (CheckMemorySizeofForComparison(*this, SizeArg, FnName, 4841 Call->getLocStart(), Call->getRParenLoc())) 4842 return; 4843 4844 // Look for 'strlcpy(dst, x, sizeof(x))' 4845 if (const Expr *Ex = getSizeOfExprArg(SizeArg)) 4846 CompareWithSrc = Ex; 4847 else { 4848 // Look for 'strlcpy(dst, x, strlen(x))' 4849 if (const CallExpr *SizeCall = dyn_cast<CallExpr>(SizeArg)) { 4850 if (SizeCall->getBuiltinCallee() == Builtin::BIstrlen && 4851 SizeCall->getNumArgs() == 1) 4852 CompareWithSrc = ignoreLiteralAdditions(SizeCall->getArg(0), Context); 4853 } 4854 } 4855 4856 if (!CompareWithSrc) 4857 return; 4858 4859 // Determine if the argument to sizeof/strlen is equal to the source 4860 // argument. In principle there's all kinds of things you could do 4861 // here, for instance creating an == expression and evaluating it with 4862 // EvaluateAsBooleanCondition, but this uses a more direct technique: 4863 const DeclRefExpr *SrcArgDRE = dyn_cast<DeclRefExpr>(SrcArg); 4864 if (!SrcArgDRE) 4865 return; 4866 4867 const DeclRefExpr *CompareWithSrcDRE = dyn_cast<DeclRefExpr>(CompareWithSrc); 4868 if (!CompareWithSrcDRE || 4869 SrcArgDRE->getDecl() != CompareWithSrcDRE->getDecl()) 4870 return; 4871 4872 const Expr *OriginalSizeArg = Call->getArg(2); 4873 Diag(CompareWithSrcDRE->getLocStart(), diag::warn_strlcpycat_wrong_size) 4874 << OriginalSizeArg->getSourceRange() << FnName; 4875 4876 // Output a FIXIT hint if the destination is an array (rather than a 4877 // pointer to an array). This could be enhanced to handle some 4878 // pointers if we know the actual size, like if DstArg is 'array+2' 4879 // we could say 'sizeof(array)-2'. 4880 const Expr *DstArg = Call->getArg(0)->IgnoreParenImpCasts(); 4881 if (!isConstantSizeArrayWithMoreThanOneElement(DstArg->getType(), Context)) 4882 return; 4883 4884 SmallString<128> sizeString; 4885 llvm::raw_svector_ostream OS(sizeString); 4886 OS << "sizeof("; 4887 DstArg->printPretty(OS, nullptr, getPrintingPolicy()); 4888 OS << ")"; 4889 4890 Diag(OriginalSizeArg->getLocStart(), diag::note_strlcpycat_wrong_size) 4891 << FixItHint::CreateReplacement(OriginalSizeArg->getSourceRange(), 4892 OS.str()); 4893 } 4894 4895 /// Check if two expressions refer to the same declaration. 4896 static bool referToTheSameDecl(const Expr *E1, const Expr *E2) { 4897 if (const DeclRefExpr *D1 = dyn_cast_or_null<DeclRefExpr>(E1)) 4898 if (const DeclRefExpr *D2 = dyn_cast_or_null<DeclRefExpr>(E2)) 4899 return D1->getDecl() == D2->getDecl(); 4900 return false; 4901 } 4902 4903 static const Expr *getStrlenExprArg(const Expr *E) { 4904 if (const CallExpr *CE = dyn_cast<CallExpr>(E)) { 4905 const FunctionDecl *FD = CE->getDirectCallee(); 4906 if (!FD || FD->getMemoryFunctionKind() != Builtin::BIstrlen) 4907 return nullptr; 4908 return CE->getArg(0)->IgnoreParenCasts(); 4909 } 4910 return nullptr; 4911 } 4912 4913 // Warn on anti-patterns as the 'size' argument to strncat. 4914 // The correct size argument should look like following: 4915 // strncat(dst, src, sizeof(dst) - strlen(dest) - 1); 4916 void Sema::CheckStrncatArguments(const CallExpr *CE, 4917 IdentifierInfo *FnName) { 4918 // Don't crash if the user has the wrong number of arguments. 4919 if (CE->getNumArgs() < 3) 4920 return; 4921 const Expr *DstArg = CE->getArg(0)->IgnoreParenCasts(); 4922 const Expr *SrcArg = CE->getArg(1)->IgnoreParenCasts(); 4923 const Expr *LenArg = CE->getArg(2)->IgnoreParenCasts(); 4924 4925 if (CheckMemorySizeofForComparison(*this, LenArg, FnName, CE->getLocStart(), 4926 CE->getRParenLoc())) 4927 return; 4928 4929 // Identify common expressions, which are wrongly used as the size argument 4930 // to strncat and may lead to buffer overflows. 4931 unsigned PatternType = 0; 4932 if (const Expr *SizeOfArg = getSizeOfExprArg(LenArg)) { 4933 // - sizeof(dst) 4934 if (referToTheSameDecl(SizeOfArg, DstArg)) 4935 PatternType = 1; 4936 // - sizeof(src) 4937 else if (referToTheSameDecl(SizeOfArg, SrcArg)) 4938 PatternType = 2; 4939 } else if (const BinaryOperator *BE = dyn_cast<BinaryOperator>(LenArg)) { 4940 if (BE->getOpcode() == BO_Sub) { 4941 const Expr *L = BE->getLHS()->IgnoreParenCasts(); 4942 const Expr *R = BE->getRHS()->IgnoreParenCasts(); 4943 // - sizeof(dst) - strlen(dst) 4944 if (referToTheSameDecl(DstArg, getSizeOfExprArg(L)) && 4945 referToTheSameDecl(DstArg, getStrlenExprArg(R))) 4946 PatternType = 1; 4947 // - sizeof(src) - (anything) 4948 else if (referToTheSameDecl(SrcArg, getSizeOfExprArg(L))) 4949 PatternType = 2; 4950 } 4951 } 4952 4953 if (PatternType == 0) 4954 return; 4955 4956 // Generate the diagnostic. 4957 SourceLocation SL = LenArg->getLocStart(); 4958 SourceRange SR = LenArg->getSourceRange(); 4959 SourceManager &SM = getSourceManager(); 4960 4961 // If the function is defined as a builtin macro, do not show macro expansion. 4962 if (SM.isMacroArgExpansion(SL)) { 4963 SL = SM.getSpellingLoc(SL); 4964 SR = SourceRange(SM.getSpellingLoc(SR.getBegin()), 4965 SM.getSpellingLoc(SR.getEnd())); 4966 } 4967 4968 // Check if the destination is an array (rather than a pointer to an array). 4969 QualType DstTy = DstArg->getType(); 4970 bool isKnownSizeArray = isConstantSizeArrayWithMoreThanOneElement(DstTy, 4971 Context); 4972 if (!isKnownSizeArray) { 4973 if (PatternType == 1) 4974 Diag(SL, diag::warn_strncat_wrong_size) << SR; 4975 else 4976 Diag(SL, diag::warn_strncat_src_size) << SR; 4977 return; 4978 } 4979 4980 if (PatternType == 1) 4981 Diag(SL, diag::warn_strncat_large_size) << SR; 4982 else 4983 Diag(SL, diag::warn_strncat_src_size) << SR; 4984 4985 SmallString<128> sizeString; 4986 llvm::raw_svector_ostream OS(sizeString); 4987 OS << "sizeof("; 4988 DstArg->printPretty(OS, nullptr, getPrintingPolicy()); 4989 OS << ") - "; 4990 OS << "strlen("; 4991 DstArg->printPretty(OS, nullptr, getPrintingPolicy()); 4992 OS << ") - 1"; 4993 4994 Diag(SL, diag::note_strncat_wrong_size) 4995 << FixItHint::CreateReplacement(SR, OS.str()); 4996 } 4997 4998 //===--- CHECK: Return Address of Stack Variable --------------------------===// 4999 5000 static Expr *EvalVal(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars, 5001 Decl *ParentDecl); 5002 static Expr *EvalAddr(Expr* E, SmallVectorImpl<DeclRefExpr *> &refVars, 5003 Decl *ParentDecl); 5004 5005 /// CheckReturnStackAddr - Check if a return statement returns the address 5006 /// of a stack variable. 5007 static void 5008 CheckReturnStackAddr(Sema &S, Expr *RetValExp, QualType lhsType, 5009 SourceLocation ReturnLoc) { 5010 5011 Expr *stackE = nullptr; 5012 SmallVector<DeclRefExpr *, 8> refVars; 5013 5014 // Perform checking for returned stack addresses, local blocks, 5015 // label addresses or references to temporaries. 5016 if (lhsType->isPointerType() || 5017 (!S.getLangOpts().ObjCAutoRefCount && lhsType->isBlockPointerType())) { 5018 stackE = EvalAddr(RetValExp, refVars, /*ParentDecl=*/nullptr); 5019 } else if (lhsType->isReferenceType()) { 5020 stackE = EvalVal(RetValExp, refVars, /*ParentDecl=*/nullptr); 5021 } 5022 5023 if (!stackE) 5024 return; // Nothing suspicious was found. 5025 5026 SourceLocation diagLoc; 5027 SourceRange diagRange; 5028 if (refVars.empty()) { 5029 diagLoc = stackE->getLocStart(); 5030 diagRange = stackE->getSourceRange(); 5031 } else { 5032 // We followed through a reference variable. 'stackE' contains the 5033 // problematic expression but we will warn at the return statement pointing 5034 // at the reference variable. We will later display the "trail" of 5035 // reference variables using notes. 5036 diagLoc = refVars[0]->getLocStart(); 5037 diagRange = refVars[0]->getSourceRange(); 5038 } 5039 5040 if (DeclRefExpr *DR = dyn_cast<DeclRefExpr>(stackE)) { //address of local var. 5041 S.Diag(diagLoc, lhsType->isReferenceType() ? diag::warn_ret_stack_ref 5042 : diag::warn_ret_stack_addr) 5043 << DR->getDecl()->getDeclName() << diagRange; 5044 } else if (isa<BlockExpr>(stackE)) { // local block. 5045 S.Diag(diagLoc, diag::err_ret_local_block) << diagRange; 5046 } else if (isa<AddrLabelExpr>(stackE)) { // address of label. 5047 S.Diag(diagLoc, diag::warn_ret_addr_label) << diagRange; 5048 } else { // local temporary. 5049 S.Diag(diagLoc, lhsType->isReferenceType() ? diag::warn_ret_local_temp_ref 5050 : diag::warn_ret_local_temp_addr) 5051 << diagRange; 5052 } 5053 5054 // Display the "trail" of reference variables that we followed until we 5055 // found the problematic expression using notes. 5056 for (unsigned i = 0, e = refVars.size(); i != e; ++i) { 5057 VarDecl *VD = cast<VarDecl>(refVars[i]->getDecl()); 5058 // If this var binds to another reference var, show the range of the next 5059 // var, otherwise the var binds to the problematic expression, in which case 5060 // show the range of the expression. 5061 SourceRange range = (i < e-1) ? refVars[i+1]->getSourceRange() 5062 : stackE->getSourceRange(); 5063 S.Diag(VD->getLocation(), diag::note_ref_var_local_bind) 5064 << VD->getDeclName() << range; 5065 } 5066 } 5067 5068 /// EvalAddr - EvalAddr and EvalVal are mutually recursive functions that 5069 /// check if the expression in a return statement evaluates to an address 5070 /// to a location on the stack, a local block, an address of a label, or a 5071 /// reference to local temporary. The recursion is used to traverse the 5072 /// AST of the return expression, with recursion backtracking when we 5073 /// encounter a subexpression that (1) clearly does not lead to one of the 5074 /// above problematic expressions (2) is something we cannot determine leads to 5075 /// a problematic expression based on such local checking. 5076 /// 5077 /// Both EvalAddr and EvalVal follow through reference variables to evaluate 5078 /// the expression that they point to. Such variables are added to the 5079 /// 'refVars' vector so that we know what the reference variable "trail" was. 5080 /// 5081 /// EvalAddr processes expressions that are pointers that are used as 5082 /// references (and not L-values). EvalVal handles all other values. 5083 /// At the base case of the recursion is a check for the above problematic 5084 /// expressions. 5085 /// 5086 /// This implementation handles: 5087 /// 5088 /// * pointer-to-pointer casts 5089 /// * implicit conversions from array references to pointers 5090 /// * taking the address of fields 5091 /// * arbitrary interplay between "&" and "*" operators 5092 /// * pointer arithmetic from an address of a stack variable 5093 /// * taking the address of an array element where the array is on the stack 5094 static Expr *EvalAddr(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars, 5095 Decl *ParentDecl) { 5096 if (E->isTypeDependent()) 5097 return nullptr; 5098 5099 // We should only be called for evaluating pointer expressions. 5100 assert((E->getType()->isAnyPointerType() || 5101 E->getType()->isBlockPointerType() || 5102 E->getType()->isObjCQualifiedIdType()) && 5103 "EvalAddr only works on pointers"); 5104 5105 E = E->IgnoreParens(); 5106 5107 // Our "symbolic interpreter" is just a dispatch off the currently 5108 // viewed AST node. We then recursively traverse the AST by calling 5109 // EvalAddr and EvalVal appropriately. 5110 switch (E->getStmtClass()) { 5111 case Stmt::DeclRefExprClass: { 5112 DeclRefExpr *DR = cast<DeclRefExpr>(E); 5113 5114 // If we leave the immediate function, the lifetime isn't about to end. 5115 if (DR->refersToEnclosingVariableOrCapture()) 5116 return nullptr; 5117 5118 if (VarDecl *V = dyn_cast<VarDecl>(DR->getDecl())) 5119 // If this is a reference variable, follow through to the expression that 5120 // it points to. 5121 if (V->hasLocalStorage() && 5122 V->getType()->isReferenceType() && V->hasInit()) { 5123 // Add the reference variable to the "trail". 5124 refVars.push_back(DR); 5125 return EvalAddr(V->getInit(), refVars, ParentDecl); 5126 } 5127 5128 return nullptr; 5129 } 5130 5131 case Stmt::UnaryOperatorClass: { 5132 // The only unary operator that make sense to handle here 5133 // is AddrOf. All others don't make sense as pointers. 5134 UnaryOperator *U = cast<UnaryOperator>(E); 5135 5136 if (U->getOpcode() == UO_AddrOf) 5137 return EvalVal(U->getSubExpr(), refVars, ParentDecl); 5138 else 5139 return nullptr; 5140 } 5141 5142 case Stmt::BinaryOperatorClass: { 5143 // Handle pointer arithmetic. All other binary operators are not valid 5144 // in this context. 5145 BinaryOperator *B = cast<BinaryOperator>(E); 5146 BinaryOperatorKind op = B->getOpcode(); 5147 5148 if (op != BO_Add && op != BO_Sub) 5149 return nullptr; 5150 5151 Expr *Base = B->getLHS(); 5152 5153 // Determine which argument is the real pointer base. It could be 5154 // the RHS argument instead of the LHS. 5155 if (!Base->getType()->isPointerType()) Base = B->getRHS(); 5156 5157 assert (Base->getType()->isPointerType()); 5158 return EvalAddr(Base, refVars, ParentDecl); 5159 } 5160 5161 // For conditional operators we need to see if either the LHS or RHS are 5162 // valid DeclRefExpr*s. If one of them is valid, we return it. 5163 case Stmt::ConditionalOperatorClass: { 5164 ConditionalOperator *C = cast<ConditionalOperator>(E); 5165 5166 // Handle the GNU extension for missing LHS. 5167 // FIXME: That isn't a ConditionalOperator, so doesn't get here. 5168 if (Expr *LHSExpr = C->getLHS()) { 5169 // In C++, we can have a throw-expression, which has 'void' type. 5170 if (!LHSExpr->getType()->isVoidType()) 5171 if (Expr *LHS = EvalAddr(LHSExpr, refVars, ParentDecl)) 5172 return LHS; 5173 } 5174 5175 // In C++, we can have a throw-expression, which has 'void' type. 5176 if (C->getRHS()->getType()->isVoidType()) 5177 return nullptr; 5178 5179 return EvalAddr(C->getRHS(), refVars, ParentDecl); 5180 } 5181 5182 case Stmt::BlockExprClass: 5183 if (cast<BlockExpr>(E)->getBlockDecl()->hasCaptures()) 5184 return E; // local block. 5185 return nullptr; 5186 5187 case Stmt::AddrLabelExprClass: 5188 return E; // address of label. 5189 5190 case Stmt::ExprWithCleanupsClass: 5191 return EvalAddr(cast<ExprWithCleanups>(E)->getSubExpr(), refVars, 5192 ParentDecl); 5193 5194 // For casts, we need to handle conversions from arrays to 5195 // pointer values, and pointer-to-pointer conversions. 5196 case Stmt::ImplicitCastExprClass: 5197 case Stmt::CStyleCastExprClass: 5198 case Stmt::CXXFunctionalCastExprClass: 5199 case Stmt::ObjCBridgedCastExprClass: 5200 case Stmt::CXXStaticCastExprClass: 5201 case Stmt::CXXDynamicCastExprClass: 5202 case Stmt::CXXConstCastExprClass: 5203 case Stmt::CXXReinterpretCastExprClass: { 5204 Expr* SubExpr = cast<CastExpr>(E)->getSubExpr(); 5205 switch (cast<CastExpr>(E)->getCastKind()) { 5206 case CK_LValueToRValue: 5207 case CK_NoOp: 5208 case CK_BaseToDerived: 5209 case CK_DerivedToBase: 5210 case CK_UncheckedDerivedToBase: 5211 case CK_Dynamic: 5212 case CK_CPointerToObjCPointerCast: 5213 case CK_BlockPointerToObjCPointerCast: 5214 case CK_AnyPointerToBlockPointerCast: 5215 return EvalAddr(SubExpr, refVars, ParentDecl); 5216 5217 case CK_ArrayToPointerDecay: 5218 return EvalVal(SubExpr, refVars, ParentDecl); 5219 5220 case CK_BitCast: 5221 if (SubExpr->getType()->isAnyPointerType() || 5222 SubExpr->getType()->isBlockPointerType() || 5223 SubExpr->getType()->isObjCQualifiedIdType()) 5224 return EvalAddr(SubExpr, refVars, ParentDecl); 5225 else 5226 return nullptr; 5227 5228 default: 5229 return nullptr; 5230 } 5231 } 5232 5233 case Stmt::MaterializeTemporaryExprClass: 5234 if (Expr *Result = EvalAddr( 5235 cast<MaterializeTemporaryExpr>(E)->GetTemporaryExpr(), 5236 refVars, ParentDecl)) 5237 return Result; 5238 5239 return E; 5240 5241 // Everything else: we simply don't reason about them. 5242 default: 5243 return nullptr; 5244 } 5245 } 5246 5247 5248 /// EvalVal - This function is complements EvalAddr in the mutual recursion. 5249 /// See the comments for EvalAddr for more details. 5250 static Expr *EvalVal(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars, 5251 Decl *ParentDecl) { 5252 do { 5253 // We should only be called for evaluating non-pointer expressions, or 5254 // expressions with a pointer type that are not used as references but instead 5255 // are l-values (e.g., DeclRefExpr with a pointer type). 5256 5257 // Our "symbolic interpreter" is just a dispatch off the currently 5258 // viewed AST node. We then recursively traverse the AST by calling 5259 // EvalAddr and EvalVal appropriately. 5260 5261 E = E->IgnoreParens(); 5262 switch (E->getStmtClass()) { 5263 case Stmt::ImplicitCastExprClass: { 5264 ImplicitCastExpr *IE = cast<ImplicitCastExpr>(E); 5265 if (IE->getValueKind() == VK_LValue) { 5266 E = IE->getSubExpr(); 5267 continue; 5268 } 5269 return nullptr; 5270 } 5271 5272 case Stmt::ExprWithCleanupsClass: 5273 return EvalVal(cast<ExprWithCleanups>(E)->getSubExpr(), refVars,ParentDecl); 5274 5275 case Stmt::DeclRefExprClass: { 5276 // When we hit a DeclRefExpr we are looking at code that refers to a 5277 // variable's name. If it's not a reference variable we check if it has 5278 // local storage within the function, and if so, return the expression. 5279 DeclRefExpr *DR = cast<DeclRefExpr>(E); 5280 5281 // If we leave the immediate function, the lifetime isn't about to end. 5282 if (DR->refersToEnclosingVariableOrCapture()) 5283 return nullptr; 5284 5285 if (VarDecl *V = dyn_cast<VarDecl>(DR->getDecl())) { 5286 // Check if it refers to itself, e.g. "int& i = i;". 5287 if (V == ParentDecl) 5288 return DR; 5289 5290 if (V->hasLocalStorage()) { 5291 if (!V->getType()->isReferenceType()) 5292 return DR; 5293 5294 // Reference variable, follow through to the expression that 5295 // it points to. 5296 if (V->hasInit()) { 5297 // Add the reference variable to the "trail". 5298 refVars.push_back(DR); 5299 return EvalVal(V->getInit(), refVars, V); 5300 } 5301 } 5302 } 5303 5304 return nullptr; 5305 } 5306 5307 case Stmt::UnaryOperatorClass: { 5308 // The only unary operator that make sense to handle here 5309 // is Deref. All others don't resolve to a "name." This includes 5310 // handling all sorts of rvalues passed to a unary operator. 5311 UnaryOperator *U = cast<UnaryOperator>(E); 5312 5313 if (U->getOpcode() == UO_Deref) 5314 return EvalAddr(U->getSubExpr(), refVars, ParentDecl); 5315 5316 return nullptr; 5317 } 5318 5319 case Stmt::ArraySubscriptExprClass: { 5320 // Array subscripts are potential references to data on the stack. We 5321 // retrieve the DeclRefExpr* for the array variable if it indeed 5322 // has local storage. 5323 return EvalAddr(cast<ArraySubscriptExpr>(E)->getBase(), refVars,ParentDecl); 5324 } 5325 5326 case Stmt::ConditionalOperatorClass: { 5327 // For conditional operators we need to see if either the LHS or RHS are 5328 // non-NULL Expr's. If one is non-NULL, we return it. 5329 ConditionalOperator *C = cast<ConditionalOperator>(E); 5330 5331 // Handle the GNU extension for missing LHS. 5332 if (Expr *LHSExpr = C->getLHS()) { 5333 // In C++, we can have a throw-expression, which has 'void' type. 5334 if (!LHSExpr->getType()->isVoidType()) 5335 if (Expr *LHS = EvalVal(LHSExpr, refVars, ParentDecl)) 5336 return LHS; 5337 } 5338 5339 // In C++, we can have a throw-expression, which has 'void' type. 5340 if (C->getRHS()->getType()->isVoidType()) 5341 return nullptr; 5342 5343 return EvalVal(C->getRHS(), refVars, ParentDecl); 5344 } 5345 5346 // Accesses to members are potential references to data on the stack. 5347 case Stmt::MemberExprClass: { 5348 MemberExpr *M = cast<MemberExpr>(E); 5349 5350 // Check for indirect access. We only want direct field accesses. 5351 if (M->isArrow()) 5352 return nullptr; 5353 5354 // Check whether the member type is itself a reference, in which case 5355 // we're not going to refer to the member, but to what the member refers to. 5356 if (M->getMemberDecl()->getType()->isReferenceType()) 5357 return nullptr; 5358 5359 return EvalVal(M->getBase(), refVars, ParentDecl); 5360 } 5361 5362 case Stmt::MaterializeTemporaryExprClass: 5363 if (Expr *Result = EvalVal( 5364 cast<MaterializeTemporaryExpr>(E)->GetTemporaryExpr(), 5365 refVars, ParentDecl)) 5366 return Result; 5367 5368 return E; 5369 5370 default: 5371 // Check that we don't return or take the address of a reference to a 5372 // temporary. This is only useful in C++. 5373 if (!E->isTypeDependent() && E->isRValue()) 5374 return E; 5375 5376 // Everything else: we simply don't reason about them. 5377 return nullptr; 5378 } 5379 } while (true); 5380 } 5381 5382 void 5383 Sema::CheckReturnValExpr(Expr *RetValExp, QualType lhsType, 5384 SourceLocation ReturnLoc, 5385 bool isObjCMethod, 5386 const AttrVec *Attrs, 5387 const FunctionDecl *FD) { 5388 CheckReturnStackAddr(*this, RetValExp, lhsType, ReturnLoc); 5389 5390 // Check if the return value is null but should not be. 5391 if (Attrs && hasSpecificAttr<ReturnsNonNullAttr>(*Attrs) && 5392 CheckNonNullExpr(*this, RetValExp)) 5393 Diag(ReturnLoc, diag::warn_null_ret) 5394 << (isObjCMethod ? 1 : 0) << RetValExp->getSourceRange(); 5395 5396 // C++11 [basic.stc.dynamic.allocation]p4: 5397 // If an allocation function declared with a non-throwing 5398 // exception-specification fails to allocate storage, it shall return 5399 // a null pointer. Any other allocation function that fails to allocate 5400 // storage shall indicate failure only by throwing an exception [...] 5401 if (FD) { 5402 OverloadedOperatorKind Op = FD->getOverloadedOperator(); 5403 if (Op == OO_New || Op == OO_Array_New) { 5404 const FunctionProtoType *Proto 5405 = FD->getType()->castAs<FunctionProtoType>(); 5406 if (!Proto->isNothrow(Context, /*ResultIfDependent*/true) && 5407 CheckNonNullExpr(*this, RetValExp)) 5408 Diag(ReturnLoc, diag::warn_operator_new_returns_null) 5409 << FD << getLangOpts().CPlusPlus11; 5410 } 5411 } 5412 } 5413 5414 //===--- CHECK: Floating-Point comparisons (-Wfloat-equal) ---------------===// 5415 5416 /// Check for comparisons of floating point operands using != and ==. 5417 /// Issue a warning if these are no self-comparisons, as they are not likely 5418 /// to do what the programmer intended. 5419 void Sema::CheckFloatComparison(SourceLocation Loc, Expr* LHS, Expr *RHS) { 5420 Expr* LeftExprSansParen = LHS->IgnoreParenImpCasts(); 5421 Expr* RightExprSansParen = RHS->IgnoreParenImpCasts(); 5422 5423 // Special case: check for x == x (which is OK). 5424 // Do not emit warnings for such cases. 5425 if (DeclRefExpr* DRL = dyn_cast<DeclRefExpr>(LeftExprSansParen)) 5426 if (DeclRefExpr* DRR = dyn_cast<DeclRefExpr>(RightExprSansParen)) 5427 if (DRL->getDecl() == DRR->getDecl()) 5428 return; 5429 5430 5431 // Special case: check for comparisons against literals that can be exactly 5432 // represented by APFloat. In such cases, do not emit a warning. This 5433 // is a heuristic: often comparison against such literals are used to 5434 // detect if a value in a variable has not changed. This clearly can 5435 // lead to false negatives. 5436 if (FloatingLiteral* FLL = dyn_cast<FloatingLiteral>(LeftExprSansParen)) { 5437 if (FLL->isExact()) 5438 return; 5439 } else 5440 if (FloatingLiteral* FLR = dyn_cast<FloatingLiteral>(RightExprSansParen)) 5441 if (FLR->isExact()) 5442 return; 5443 5444 // Check for comparisons with builtin types. 5445 if (CallExpr* CL = dyn_cast<CallExpr>(LeftExprSansParen)) 5446 if (CL->getBuiltinCallee()) 5447 return; 5448 5449 if (CallExpr* CR = dyn_cast<CallExpr>(RightExprSansParen)) 5450 if (CR->getBuiltinCallee()) 5451 return; 5452 5453 // Emit the diagnostic. 5454 Diag(Loc, diag::warn_floatingpoint_eq) 5455 << LHS->getSourceRange() << RHS->getSourceRange(); 5456 } 5457 5458 //===--- CHECK: Integer mixed-sign comparisons (-Wsign-compare) --------===// 5459 //===--- CHECK: Lossy implicit conversions (-Wconversion) --------------===// 5460 5461 namespace { 5462 5463 /// Structure recording the 'active' range of an integer-valued 5464 /// expression. 5465 struct IntRange { 5466 /// The number of bits active in the int. 5467 unsigned Width; 5468 5469 /// True if the int is known not to have negative values. 5470 bool NonNegative; 5471 5472 IntRange(unsigned Width, bool NonNegative) 5473 : Width(Width), NonNegative(NonNegative) 5474 {} 5475 5476 /// Returns the range of the bool type. 5477 static IntRange forBoolType() { 5478 return IntRange(1, true); 5479 } 5480 5481 /// Returns the range of an opaque value of the given integral type. 5482 static IntRange forValueOfType(ASTContext &C, QualType T) { 5483 return forValueOfCanonicalType(C, 5484 T->getCanonicalTypeInternal().getTypePtr()); 5485 } 5486 5487 /// Returns the range of an opaque value of a canonical integral type. 5488 static IntRange forValueOfCanonicalType(ASTContext &C, const Type *T) { 5489 assert(T->isCanonicalUnqualified()); 5490 5491 if (const VectorType *VT = dyn_cast<VectorType>(T)) 5492 T = VT->getElementType().getTypePtr(); 5493 if (const ComplexType *CT = dyn_cast<ComplexType>(T)) 5494 T = CT->getElementType().getTypePtr(); 5495 if (const AtomicType *AT = dyn_cast<AtomicType>(T)) 5496 T = AT->getValueType().getTypePtr(); 5497 5498 // For enum types, use the known bit width of the enumerators. 5499 if (const EnumType *ET = dyn_cast<EnumType>(T)) { 5500 EnumDecl *Enum = ET->getDecl(); 5501 if (!Enum->isCompleteDefinition()) 5502 return IntRange(C.getIntWidth(QualType(T, 0)), false); 5503 5504 unsigned NumPositive = Enum->getNumPositiveBits(); 5505 unsigned NumNegative = Enum->getNumNegativeBits(); 5506 5507 if (NumNegative == 0) 5508 return IntRange(NumPositive, true/*NonNegative*/); 5509 else 5510 return IntRange(std::max(NumPositive + 1, NumNegative), 5511 false/*NonNegative*/); 5512 } 5513 5514 const BuiltinType *BT = cast<BuiltinType>(T); 5515 assert(BT->isInteger()); 5516 5517 return IntRange(C.getIntWidth(QualType(T, 0)), BT->isUnsignedInteger()); 5518 } 5519 5520 /// Returns the "target" range of a canonical integral type, i.e. 5521 /// the range of values expressible in the type. 5522 /// 5523 /// This matches forValueOfCanonicalType except that enums have the 5524 /// full range of their type, not the range of their enumerators. 5525 static IntRange forTargetOfCanonicalType(ASTContext &C, const Type *T) { 5526 assert(T->isCanonicalUnqualified()); 5527 5528 if (const VectorType *VT = dyn_cast<VectorType>(T)) 5529 T = VT->getElementType().getTypePtr(); 5530 if (const ComplexType *CT = dyn_cast<ComplexType>(T)) 5531 T = CT->getElementType().getTypePtr(); 5532 if (const AtomicType *AT = dyn_cast<AtomicType>(T)) 5533 T = AT->getValueType().getTypePtr(); 5534 if (const EnumType *ET = dyn_cast<EnumType>(T)) 5535 T = C.getCanonicalType(ET->getDecl()->getIntegerType()).getTypePtr(); 5536 5537 const BuiltinType *BT = cast<BuiltinType>(T); 5538 assert(BT->isInteger()); 5539 5540 return IntRange(C.getIntWidth(QualType(T, 0)), BT->isUnsignedInteger()); 5541 } 5542 5543 /// Returns the supremum of two ranges: i.e. their conservative merge. 5544 static IntRange join(IntRange L, IntRange R) { 5545 return IntRange(std::max(L.Width, R.Width), 5546 L.NonNegative && R.NonNegative); 5547 } 5548 5549 /// Returns the infinum of two ranges: i.e. their aggressive merge. 5550 static IntRange meet(IntRange L, IntRange R) { 5551 return IntRange(std::min(L.Width, R.Width), 5552 L.NonNegative || R.NonNegative); 5553 } 5554 }; 5555 5556 static IntRange GetValueRange(ASTContext &C, llvm::APSInt &value, 5557 unsigned MaxWidth) { 5558 if (value.isSigned() && value.isNegative()) 5559 return IntRange(value.getMinSignedBits(), false); 5560 5561 if (value.getBitWidth() > MaxWidth) 5562 value = value.trunc(MaxWidth); 5563 5564 // isNonNegative() just checks the sign bit without considering 5565 // signedness. 5566 return IntRange(value.getActiveBits(), true); 5567 } 5568 5569 static IntRange GetValueRange(ASTContext &C, APValue &result, QualType Ty, 5570 unsigned MaxWidth) { 5571 if (result.isInt()) 5572 return GetValueRange(C, result.getInt(), MaxWidth); 5573 5574 if (result.isVector()) { 5575 IntRange R = GetValueRange(C, result.getVectorElt(0), Ty, MaxWidth); 5576 for (unsigned i = 1, e = result.getVectorLength(); i != e; ++i) { 5577 IntRange El = GetValueRange(C, result.getVectorElt(i), Ty, MaxWidth); 5578 R = IntRange::join(R, El); 5579 } 5580 return R; 5581 } 5582 5583 if (result.isComplexInt()) { 5584 IntRange R = GetValueRange(C, result.getComplexIntReal(), MaxWidth); 5585 IntRange I = GetValueRange(C, result.getComplexIntImag(), MaxWidth); 5586 return IntRange::join(R, I); 5587 } 5588 5589 // This can happen with lossless casts to intptr_t of "based" lvalues. 5590 // Assume it might use arbitrary bits. 5591 // FIXME: The only reason we need to pass the type in here is to get 5592 // the sign right on this one case. It would be nice if APValue 5593 // preserved this. 5594 assert(result.isLValue() || result.isAddrLabelDiff()); 5595 return IntRange(MaxWidth, Ty->isUnsignedIntegerOrEnumerationType()); 5596 } 5597 5598 static QualType GetExprType(Expr *E) { 5599 QualType Ty = E->getType(); 5600 if (const AtomicType *AtomicRHS = Ty->getAs<AtomicType>()) 5601 Ty = AtomicRHS->getValueType(); 5602 return Ty; 5603 } 5604 5605 /// Pseudo-evaluate the given integer expression, estimating the 5606 /// range of values it might take. 5607 /// 5608 /// \param MaxWidth - the width to which the value will be truncated 5609 static IntRange GetExprRange(ASTContext &C, Expr *E, unsigned MaxWidth) { 5610 E = E->IgnoreParens(); 5611 5612 // Try a full evaluation first. 5613 Expr::EvalResult result; 5614 if (E->EvaluateAsRValue(result, C)) 5615 return GetValueRange(C, result.Val, GetExprType(E), MaxWidth); 5616 5617 // I think we only want to look through implicit casts here; if the 5618 // user has an explicit widening cast, we should treat the value as 5619 // being of the new, wider type. 5620 if (ImplicitCastExpr *CE = dyn_cast<ImplicitCastExpr>(E)) { 5621 if (CE->getCastKind() == CK_NoOp || CE->getCastKind() == CK_LValueToRValue) 5622 return GetExprRange(C, CE->getSubExpr(), MaxWidth); 5623 5624 IntRange OutputTypeRange = IntRange::forValueOfType(C, GetExprType(CE)); 5625 5626 bool isIntegerCast = (CE->getCastKind() == CK_IntegralCast); 5627 5628 // Assume that non-integer casts can span the full range of the type. 5629 if (!isIntegerCast) 5630 return OutputTypeRange; 5631 5632 IntRange SubRange 5633 = GetExprRange(C, CE->getSubExpr(), 5634 std::min(MaxWidth, OutputTypeRange.Width)); 5635 5636 // Bail out if the subexpr's range is as wide as the cast type. 5637 if (SubRange.Width >= OutputTypeRange.Width) 5638 return OutputTypeRange; 5639 5640 // Otherwise, we take the smaller width, and we're non-negative if 5641 // either the output type or the subexpr is. 5642 return IntRange(SubRange.Width, 5643 SubRange.NonNegative || OutputTypeRange.NonNegative); 5644 } 5645 5646 if (ConditionalOperator *CO = dyn_cast<ConditionalOperator>(E)) { 5647 // If we can fold the condition, just take that operand. 5648 bool CondResult; 5649 if (CO->getCond()->EvaluateAsBooleanCondition(CondResult, C)) 5650 return GetExprRange(C, CondResult ? CO->getTrueExpr() 5651 : CO->getFalseExpr(), 5652 MaxWidth); 5653 5654 // Otherwise, conservatively merge. 5655 IntRange L = GetExprRange(C, CO->getTrueExpr(), MaxWidth); 5656 IntRange R = GetExprRange(C, CO->getFalseExpr(), MaxWidth); 5657 return IntRange::join(L, R); 5658 } 5659 5660 if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) { 5661 switch (BO->getOpcode()) { 5662 5663 // Boolean-valued operations are single-bit and positive. 5664 case BO_LAnd: 5665 case BO_LOr: 5666 case BO_LT: 5667 case BO_GT: 5668 case BO_LE: 5669 case BO_GE: 5670 case BO_EQ: 5671 case BO_NE: 5672 return IntRange::forBoolType(); 5673 5674 // The type of the assignments is the type of the LHS, so the RHS 5675 // is not necessarily the same type. 5676 case BO_MulAssign: 5677 case BO_DivAssign: 5678 case BO_RemAssign: 5679 case BO_AddAssign: 5680 case BO_SubAssign: 5681 case BO_XorAssign: 5682 case BO_OrAssign: 5683 // TODO: bitfields? 5684 return IntRange::forValueOfType(C, GetExprType(E)); 5685 5686 // Simple assignments just pass through the RHS, which will have 5687 // been coerced to the LHS type. 5688 case BO_Assign: 5689 // TODO: bitfields? 5690 return GetExprRange(C, BO->getRHS(), MaxWidth); 5691 5692 // Operations with opaque sources are black-listed. 5693 case BO_PtrMemD: 5694 case BO_PtrMemI: 5695 return IntRange::forValueOfType(C, GetExprType(E)); 5696 5697 // Bitwise-and uses the *infinum* of the two source ranges. 5698 case BO_And: 5699 case BO_AndAssign: 5700 return IntRange::meet(GetExprRange(C, BO->getLHS(), MaxWidth), 5701 GetExprRange(C, BO->getRHS(), MaxWidth)); 5702 5703 // Left shift gets black-listed based on a judgement call. 5704 case BO_Shl: 5705 // ...except that we want to treat '1 << (blah)' as logically 5706 // positive. It's an important idiom. 5707 if (IntegerLiteral *I 5708 = dyn_cast<IntegerLiteral>(BO->getLHS()->IgnoreParenCasts())) { 5709 if (I->getValue() == 1) { 5710 IntRange R = IntRange::forValueOfType(C, GetExprType(E)); 5711 return IntRange(R.Width, /*NonNegative*/ true); 5712 } 5713 } 5714 // fallthrough 5715 5716 case BO_ShlAssign: 5717 return IntRange::forValueOfType(C, GetExprType(E)); 5718 5719 // Right shift by a constant can narrow its left argument. 5720 case BO_Shr: 5721 case BO_ShrAssign: { 5722 IntRange L = GetExprRange(C, BO->getLHS(), MaxWidth); 5723 5724 // If the shift amount is a positive constant, drop the width by 5725 // that much. 5726 llvm::APSInt shift; 5727 if (BO->getRHS()->isIntegerConstantExpr(shift, C) && 5728 shift.isNonNegative()) { 5729 unsigned zext = shift.getZExtValue(); 5730 if (zext >= L.Width) 5731 L.Width = (L.NonNegative ? 0 : 1); 5732 else 5733 L.Width -= zext; 5734 } 5735 5736 return L; 5737 } 5738 5739 // Comma acts as its right operand. 5740 case BO_Comma: 5741 return GetExprRange(C, BO->getRHS(), MaxWidth); 5742 5743 // Black-list pointer subtractions. 5744 case BO_Sub: 5745 if (BO->getLHS()->getType()->isPointerType()) 5746 return IntRange::forValueOfType(C, GetExprType(E)); 5747 break; 5748 5749 // The width of a division result is mostly determined by the size 5750 // of the LHS. 5751 case BO_Div: { 5752 // Don't 'pre-truncate' the operands. 5753 unsigned opWidth = C.getIntWidth(GetExprType(E)); 5754 IntRange L = GetExprRange(C, BO->getLHS(), opWidth); 5755 5756 // If the divisor is constant, use that. 5757 llvm::APSInt divisor; 5758 if (BO->getRHS()->isIntegerConstantExpr(divisor, C)) { 5759 unsigned log2 = divisor.logBase2(); // floor(log_2(divisor)) 5760 if (log2 >= L.Width) 5761 L.Width = (L.NonNegative ? 0 : 1); 5762 else 5763 L.Width = std::min(L.Width - log2, MaxWidth); 5764 return L; 5765 } 5766 5767 // Otherwise, just use the LHS's width. 5768 IntRange R = GetExprRange(C, BO->getRHS(), opWidth); 5769 return IntRange(L.Width, L.NonNegative && R.NonNegative); 5770 } 5771 5772 // The result of a remainder can't be larger than the result of 5773 // either side. 5774 case BO_Rem: { 5775 // Don't 'pre-truncate' the operands. 5776 unsigned opWidth = C.getIntWidth(GetExprType(E)); 5777 IntRange L = GetExprRange(C, BO->getLHS(), opWidth); 5778 IntRange R = GetExprRange(C, BO->getRHS(), opWidth); 5779 5780 IntRange meet = IntRange::meet(L, R); 5781 meet.Width = std::min(meet.Width, MaxWidth); 5782 return meet; 5783 } 5784 5785 // The default behavior is okay for these. 5786 case BO_Mul: 5787 case BO_Add: 5788 case BO_Xor: 5789 case BO_Or: 5790 break; 5791 } 5792 5793 // The default case is to treat the operation as if it were closed 5794 // on the narrowest type that encompasses both operands. 5795 IntRange L = GetExprRange(C, BO->getLHS(), MaxWidth); 5796 IntRange R = GetExprRange(C, BO->getRHS(), MaxWidth); 5797 return IntRange::join(L, R); 5798 } 5799 5800 if (UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) { 5801 switch (UO->getOpcode()) { 5802 // Boolean-valued operations are white-listed. 5803 case UO_LNot: 5804 return IntRange::forBoolType(); 5805 5806 // Operations with opaque sources are black-listed. 5807 case UO_Deref: 5808 case UO_AddrOf: // should be impossible 5809 return IntRange::forValueOfType(C, GetExprType(E)); 5810 5811 default: 5812 return GetExprRange(C, UO->getSubExpr(), MaxWidth); 5813 } 5814 } 5815 5816 if (OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(E)) 5817 return GetExprRange(C, OVE->getSourceExpr(), MaxWidth); 5818 5819 if (FieldDecl *BitField = E->getSourceBitField()) 5820 return IntRange(BitField->getBitWidthValue(C), 5821 BitField->getType()->isUnsignedIntegerOrEnumerationType()); 5822 5823 return IntRange::forValueOfType(C, GetExprType(E)); 5824 } 5825 5826 static IntRange GetExprRange(ASTContext &C, Expr *E) { 5827 return GetExprRange(C, E, C.getIntWidth(GetExprType(E))); 5828 } 5829 5830 /// Checks whether the given value, which currently has the given 5831 /// source semantics, has the same value when coerced through the 5832 /// target semantics. 5833 static bool IsSameFloatAfterCast(const llvm::APFloat &value, 5834 const llvm::fltSemantics &Src, 5835 const llvm::fltSemantics &Tgt) { 5836 llvm::APFloat truncated = value; 5837 5838 bool ignored; 5839 truncated.convert(Src, llvm::APFloat::rmNearestTiesToEven, &ignored); 5840 truncated.convert(Tgt, llvm::APFloat::rmNearestTiesToEven, &ignored); 5841 5842 return truncated.bitwiseIsEqual(value); 5843 } 5844 5845 /// Checks whether the given value, which currently has the given 5846 /// source semantics, has the same value when coerced through the 5847 /// target semantics. 5848 /// 5849 /// The value might be a vector of floats (or a complex number). 5850 static bool IsSameFloatAfterCast(const APValue &value, 5851 const llvm::fltSemantics &Src, 5852 const llvm::fltSemantics &Tgt) { 5853 if (value.isFloat()) 5854 return IsSameFloatAfterCast(value.getFloat(), Src, Tgt); 5855 5856 if (value.isVector()) { 5857 for (unsigned i = 0, e = value.getVectorLength(); i != e; ++i) 5858 if (!IsSameFloatAfterCast(value.getVectorElt(i), Src, Tgt)) 5859 return false; 5860 return true; 5861 } 5862 5863 assert(value.isComplexFloat()); 5864 return (IsSameFloatAfterCast(value.getComplexFloatReal(), Src, Tgt) && 5865 IsSameFloatAfterCast(value.getComplexFloatImag(), Src, Tgt)); 5866 } 5867 5868 static void AnalyzeImplicitConversions(Sema &S, Expr *E, SourceLocation CC); 5869 5870 static bool IsZero(Sema &S, Expr *E) { 5871 // Suppress cases where we are comparing against an enum constant. 5872 if (const DeclRefExpr *DR = 5873 dyn_cast<DeclRefExpr>(E->IgnoreParenImpCasts())) 5874 if (isa<EnumConstantDecl>(DR->getDecl())) 5875 return false; 5876 5877 // Suppress cases where the '0' value is expanded from a macro. 5878 if (E->getLocStart().isMacroID()) 5879 return false; 5880 5881 llvm::APSInt Value; 5882 return E->isIntegerConstantExpr(Value, S.Context) && Value == 0; 5883 } 5884 5885 static bool HasEnumType(Expr *E) { 5886 // Strip off implicit integral promotions. 5887 while (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) { 5888 if (ICE->getCastKind() != CK_IntegralCast && 5889 ICE->getCastKind() != CK_NoOp) 5890 break; 5891 E = ICE->getSubExpr(); 5892 } 5893 5894 return E->getType()->isEnumeralType(); 5895 } 5896 5897 static void CheckTrivialUnsignedComparison(Sema &S, BinaryOperator *E) { 5898 // Disable warning in template instantiations. 5899 if (!S.ActiveTemplateInstantiations.empty()) 5900 return; 5901 5902 BinaryOperatorKind op = E->getOpcode(); 5903 if (E->isValueDependent()) 5904 return; 5905 5906 if (op == BO_LT && IsZero(S, E->getRHS())) { 5907 S.Diag(E->getOperatorLoc(), diag::warn_lunsigned_always_true_comparison) 5908 << "< 0" << "false" << HasEnumType(E->getLHS()) 5909 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); 5910 } else if (op == BO_GE && IsZero(S, E->getRHS())) { 5911 S.Diag(E->getOperatorLoc(), diag::warn_lunsigned_always_true_comparison) 5912 << ">= 0" << "true" << HasEnumType(E->getLHS()) 5913 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); 5914 } else if (op == BO_GT && IsZero(S, E->getLHS())) { 5915 S.Diag(E->getOperatorLoc(), diag::warn_runsigned_always_true_comparison) 5916 << "0 >" << "false" << HasEnumType(E->getRHS()) 5917 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); 5918 } else if (op == BO_LE && IsZero(S, E->getLHS())) { 5919 S.Diag(E->getOperatorLoc(), diag::warn_runsigned_always_true_comparison) 5920 << "0 <=" << "true" << HasEnumType(E->getRHS()) 5921 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); 5922 } 5923 } 5924 5925 static void DiagnoseOutOfRangeComparison(Sema &S, BinaryOperator *E, 5926 Expr *Constant, Expr *Other, 5927 llvm::APSInt Value, 5928 bool RhsConstant) { 5929 // Disable warning in template instantiations. 5930 if (!S.ActiveTemplateInstantiations.empty()) 5931 return; 5932 5933 // TODO: Investigate using GetExprRange() to get tighter bounds 5934 // on the bit ranges. 5935 QualType OtherT = Other->getType(); 5936 if (const AtomicType *AT = dyn_cast<AtomicType>(OtherT)) 5937 OtherT = AT->getValueType(); 5938 IntRange OtherRange = IntRange::forValueOfType(S.Context, OtherT); 5939 unsigned OtherWidth = OtherRange.Width; 5940 5941 bool OtherIsBooleanType = Other->isKnownToHaveBooleanValue(); 5942 5943 // 0 values are handled later by CheckTrivialUnsignedComparison(). 5944 if ((Value == 0) && (!OtherIsBooleanType)) 5945 return; 5946 5947 BinaryOperatorKind op = E->getOpcode(); 5948 bool IsTrue = true; 5949 5950 // Used for diagnostic printout. 5951 enum { 5952 LiteralConstant = 0, 5953 CXXBoolLiteralTrue, 5954 CXXBoolLiteralFalse 5955 } LiteralOrBoolConstant = LiteralConstant; 5956 5957 if (!OtherIsBooleanType) { 5958 QualType ConstantT = Constant->getType(); 5959 QualType CommonT = E->getLHS()->getType(); 5960 5961 if (S.Context.hasSameUnqualifiedType(OtherT, ConstantT)) 5962 return; 5963 assert((OtherT->isIntegerType() && ConstantT->isIntegerType()) && 5964 "comparison with non-integer type"); 5965 5966 bool ConstantSigned = ConstantT->isSignedIntegerType(); 5967 bool CommonSigned = CommonT->isSignedIntegerType(); 5968 5969 bool EqualityOnly = false; 5970 5971 if (CommonSigned) { 5972 // The common type is signed, therefore no signed to unsigned conversion. 5973 if (!OtherRange.NonNegative) { 5974 // Check that the constant is representable in type OtherT. 5975 if (ConstantSigned) { 5976 if (OtherWidth >= Value.getMinSignedBits()) 5977 return; 5978 } else { // !ConstantSigned 5979 if (OtherWidth >= Value.getActiveBits() + 1) 5980 return; 5981 } 5982 } else { // !OtherSigned 5983 // Check that the constant is representable in type OtherT. 5984 // Negative values are out of range. 5985 if (ConstantSigned) { 5986 if (Value.isNonNegative() && OtherWidth >= Value.getActiveBits()) 5987 return; 5988 } else { // !ConstantSigned 5989 if (OtherWidth >= Value.getActiveBits()) 5990 return; 5991 } 5992 } 5993 } else { // !CommonSigned 5994 if (OtherRange.NonNegative) { 5995 if (OtherWidth >= Value.getActiveBits()) 5996 return; 5997 } else { // OtherSigned 5998 assert(!ConstantSigned && 5999 "Two signed types converted to unsigned types."); 6000 // Check to see if the constant is representable in OtherT. 6001 if (OtherWidth > Value.getActiveBits()) 6002 return; 6003 // Check to see if the constant is equivalent to a negative value 6004 // cast to CommonT. 6005 if (S.Context.getIntWidth(ConstantT) == 6006 S.Context.getIntWidth(CommonT) && 6007 Value.isNegative() && Value.getMinSignedBits() <= OtherWidth) 6008 return; 6009 // The constant value rests between values that OtherT can represent 6010 // after conversion. Relational comparison still works, but equality 6011 // comparisons will be tautological. 6012 EqualityOnly = true; 6013 } 6014 } 6015 6016 bool PositiveConstant = !ConstantSigned || Value.isNonNegative(); 6017 6018 if (op == BO_EQ || op == BO_NE) { 6019 IsTrue = op == BO_NE; 6020 } else if (EqualityOnly) { 6021 return; 6022 } else if (RhsConstant) { 6023 if (op == BO_GT || op == BO_GE) 6024 IsTrue = !PositiveConstant; 6025 else // op == BO_LT || op == BO_LE 6026 IsTrue = PositiveConstant; 6027 } else { 6028 if (op == BO_LT || op == BO_LE) 6029 IsTrue = !PositiveConstant; 6030 else // op == BO_GT || op == BO_GE 6031 IsTrue = PositiveConstant; 6032 } 6033 } else { 6034 // Other isKnownToHaveBooleanValue 6035 enum CompareBoolWithConstantResult { AFals, ATrue, Unkwn }; 6036 enum ConstantValue { LT_Zero, Zero, One, GT_One, SizeOfConstVal }; 6037 enum ConstantSide { Lhs, Rhs, SizeOfConstSides }; 6038 6039 static const struct LinkedConditions { 6040 CompareBoolWithConstantResult BO_LT_OP[SizeOfConstSides][SizeOfConstVal]; 6041 CompareBoolWithConstantResult BO_GT_OP[SizeOfConstSides][SizeOfConstVal]; 6042 CompareBoolWithConstantResult BO_LE_OP[SizeOfConstSides][SizeOfConstVal]; 6043 CompareBoolWithConstantResult BO_GE_OP[SizeOfConstSides][SizeOfConstVal]; 6044 CompareBoolWithConstantResult BO_EQ_OP[SizeOfConstSides][SizeOfConstVal]; 6045 CompareBoolWithConstantResult BO_NE_OP[SizeOfConstSides][SizeOfConstVal]; 6046 6047 } TruthTable = { 6048 // Constant on LHS. | Constant on RHS. | 6049 // LT_Zero| Zero | One |GT_One| LT_Zero| Zero | One |GT_One| 6050 { { ATrue, Unkwn, AFals, AFals }, { AFals, AFals, Unkwn, ATrue } }, 6051 { { AFals, AFals, Unkwn, ATrue }, { ATrue, Unkwn, AFals, AFals } }, 6052 { { ATrue, ATrue, Unkwn, AFals }, { AFals, Unkwn, ATrue, ATrue } }, 6053 { { AFals, Unkwn, ATrue, ATrue }, { ATrue, ATrue, Unkwn, AFals } }, 6054 { { AFals, Unkwn, Unkwn, AFals }, { AFals, Unkwn, Unkwn, AFals } }, 6055 { { ATrue, Unkwn, Unkwn, ATrue }, { ATrue, Unkwn, Unkwn, ATrue } } 6056 }; 6057 6058 bool ConstantIsBoolLiteral = isa<CXXBoolLiteralExpr>(Constant); 6059 6060 enum ConstantValue ConstVal = Zero; 6061 if (Value.isUnsigned() || Value.isNonNegative()) { 6062 if (Value == 0) { 6063 LiteralOrBoolConstant = 6064 ConstantIsBoolLiteral ? CXXBoolLiteralFalse : LiteralConstant; 6065 ConstVal = Zero; 6066 } else if (Value == 1) { 6067 LiteralOrBoolConstant = 6068 ConstantIsBoolLiteral ? CXXBoolLiteralTrue : LiteralConstant; 6069 ConstVal = One; 6070 } else { 6071 LiteralOrBoolConstant = LiteralConstant; 6072 ConstVal = GT_One; 6073 } 6074 } else { 6075 ConstVal = LT_Zero; 6076 } 6077 6078 CompareBoolWithConstantResult CmpRes; 6079 6080 switch (op) { 6081 case BO_LT: 6082 CmpRes = TruthTable.BO_LT_OP[RhsConstant][ConstVal]; 6083 break; 6084 case BO_GT: 6085 CmpRes = TruthTable.BO_GT_OP[RhsConstant][ConstVal]; 6086 break; 6087 case BO_LE: 6088 CmpRes = TruthTable.BO_LE_OP[RhsConstant][ConstVal]; 6089 break; 6090 case BO_GE: 6091 CmpRes = TruthTable.BO_GE_OP[RhsConstant][ConstVal]; 6092 break; 6093 case BO_EQ: 6094 CmpRes = TruthTable.BO_EQ_OP[RhsConstant][ConstVal]; 6095 break; 6096 case BO_NE: 6097 CmpRes = TruthTable.BO_NE_OP[RhsConstant][ConstVal]; 6098 break; 6099 default: 6100 CmpRes = Unkwn; 6101 break; 6102 } 6103 6104 if (CmpRes == AFals) { 6105 IsTrue = false; 6106 } else if (CmpRes == ATrue) { 6107 IsTrue = true; 6108 } else { 6109 return; 6110 } 6111 } 6112 6113 // If this is a comparison to an enum constant, include that 6114 // constant in the diagnostic. 6115 const EnumConstantDecl *ED = nullptr; 6116 if (const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(Constant)) 6117 ED = dyn_cast<EnumConstantDecl>(DR->getDecl()); 6118 6119 SmallString<64> PrettySourceValue; 6120 llvm::raw_svector_ostream OS(PrettySourceValue); 6121 if (ED) 6122 OS << '\'' << *ED << "' (" << Value << ")"; 6123 else 6124 OS << Value; 6125 6126 S.DiagRuntimeBehavior( 6127 E->getOperatorLoc(), E, 6128 S.PDiag(diag::warn_out_of_range_compare) 6129 << OS.str() << LiteralOrBoolConstant 6130 << OtherT << (OtherIsBooleanType && !OtherT->isBooleanType()) << IsTrue 6131 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange()); 6132 } 6133 6134 /// Analyze the operands of the given comparison. Implements the 6135 /// fallback case from AnalyzeComparison. 6136 static void AnalyzeImpConvsInComparison(Sema &S, BinaryOperator *E) { 6137 AnalyzeImplicitConversions(S, E->getLHS(), E->getOperatorLoc()); 6138 AnalyzeImplicitConversions(S, E->getRHS(), E->getOperatorLoc()); 6139 } 6140 6141 /// \brief Implements -Wsign-compare. 6142 /// 6143 /// \param E the binary operator to check for warnings 6144 static void AnalyzeComparison(Sema &S, BinaryOperator *E) { 6145 // The type the comparison is being performed in. 6146 QualType T = E->getLHS()->getType(); 6147 6148 // Only analyze comparison operators where both sides have been converted to 6149 // the same type. 6150 if (!S.Context.hasSameUnqualifiedType(T, E->getRHS()->getType())) 6151 return AnalyzeImpConvsInComparison(S, E); 6152 6153 // Don't analyze value-dependent comparisons directly. 6154 if (E->isValueDependent()) 6155 return AnalyzeImpConvsInComparison(S, E); 6156 6157 Expr *LHS = E->getLHS()->IgnoreParenImpCasts(); 6158 Expr *RHS = E->getRHS()->IgnoreParenImpCasts(); 6159 6160 bool IsComparisonConstant = false; 6161 6162 // Check whether an integer constant comparison results in a value 6163 // of 'true' or 'false'. 6164 if (T->isIntegralType(S.Context)) { 6165 llvm::APSInt RHSValue; 6166 bool IsRHSIntegralLiteral = 6167 RHS->isIntegerConstantExpr(RHSValue, S.Context); 6168 llvm::APSInt LHSValue; 6169 bool IsLHSIntegralLiteral = 6170 LHS->isIntegerConstantExpr(LHSValue, S.Context); 6171 if (IsRHSIntegralLiteral && !IsLHSIntegralLiteral) 6172 DiagnoseOutOfRangeComparison(S, E, RHS, LHS, RHSValue, true); 6173 else if (!IsRHSIntegralLiteral && IsLHSIntegralLiteral) 6174 DiagnoseOutOfRangeComparison(S, E, LHS, RHS, LHSValue, false); 6175 else 6176 IsComparisonConstant = 6177 (IsRHSIntegralLiteral && IsLHSIntegralLiteral); 6178 } else if (!T->hasUnsignedIntegerRepresentation()) 6179 IsComparisonConstant = E->isIntegerConstantExpr(S.Context); 6180 6181 // We don't do anything special if this isn't an unsigned integral 6182 // comparison: we're only interested in integral comparisons, and 6183 // signed comparisons only happen in cases we don't care to warn about. 6184 // 6185 // We also don't care about value-dependent expressions or expressions 6186 // whose result is a constant. 6187 if (!T->hasUnsignedIntegerRepresentation() || IsComparisonConstant) 6188 return AnalyzeImpConvsInComparison(S, E); 6189 6190 // Check to see if one of the (unmodified) operands is of different 6191 // signedness. 6192 Expr *signedOperand, *unsignedOperand; 6193 if (LHS->getType()->hasSignedIntegerRepresentation()) { 6194 assert(!RHS->getType()->hasSignedIntegerRepresentation() && 6195 "unsigned comparison between two signed integer expressions?"); 6196 signedOperand = LHS; 6197 unsignedOperand = RHS; 6198 } else if (RHS->getType()->hasSignedIntegerRepresentation()) { 6199 signedOperand = RHS; 6200 unsignedOperand = LHS; 6201 } else { 6202 CheckTrivialUnsignedComparison(S, E); 6203 return AnalyzeImpConvsInComparison(S, E); 6204 } 6205 6206 // Otherwise, calculate the effective range of the signed operand. 6207 IntRange signedRange = GetExprRange(S.Context, signedOperand); 6208 6209 // Go ahead and analyze implicit conversions in the operands. Note 6210 // that we skip the implicit conversions on both sides. 6211 AnalyzeImplicitConversions(S, LHS, E->getOperatorLoc()); 6212 AnalyzeImplicitConversions(S, RHS, E->getOperatorLoc()); 6213 6214 // If the signed range is non-negative, -Wsign-compare won't fire, 6215 // but we should still check for comparisons which are always true 6216 // or false. 6217 if (signedRange.NonNegative) 6218 return CheckTrivialUnsignedComparison(S, E); 6219 6220 // For (in)equality comparisons, if the unsigned operand is a 6221 // constant which cannot collide with a overflowed signed operand, 6222 // then reinterpreting the signed operand as unsigned will not 6223 // change the result of the comparison. 6224 if (E->isEqualityOp()) { 6225 unsigned comparisonWidth = S.Context.getIntWidth(T); 6226 IntRange unsignedRange = GetExprRange(S.Context, unsignedOperand); 6227 6228 // We should never be unable to prove that the unsigned operand is 6229 // non-negative. 6230 assert(unsignedRange.NonNegative && "unsigned range includes negative?"); 6231 6232 if (unsignedRange.Width < comparisonWidth) 6233 return; 6234 } 6235 6236 S.DiagRuntimeBehavior(E->getOperatorLoc(), E, 6237 S.PDiag(diag::warn_mixed_sign_comparison) 6238 << LHS->getType() << RHS->getType() 6239 << LHS->getSourceRange() << RHS->getSourceRange()); 6240 } 6241 6242 /// Analyzes an attempt to assign the given value to a bitfield. 6243 /// 6244 /// Returns true if there was something fishy about the attempt. 6245 static bool AnalyzeBitFieldAssignment(Sema &S, FieldDecl *Bitfield, Expr *Init, 6246 SourceLocation InitLoc) { 6247 assert(Bitfield->isBitField()); 6248 if (Bitfield->isInvalidDecl()) 6249 return false; 6250 6251 // White-list bool bitfields. 6252 if (Bitfield->getType()->isBooleanType()) 6253 return false; 6254 6255 // Ignore value- or type-dependent expressions. 6256 if (Bitfield->getBitWidth()->isValueDependent() || 6257 Bitfield->getBitWidth()->isTypeDependent() || 6258 Init->isValueDependent() || 6259 Init->isTypeDependent()) 6260 return false; 6261 6262 Expr *OriginalInit = Init->IgnoreParenImpCasts(); 6263 6264 llvm::APSInt Value; 6265 if (!OriginalInit->EvaluateAsInt(Value, S.Context, Expr::SE_AllowSideEffects)) 6266 return false; 6267 6268 unsigned OriginalWidth = Value.getBitWidth(); 6269 unsigned FieldWidth = Bitfield->getBitWidthValue(S.Context); 6270 6271 if (OriginalWidth <= FieldWidth) 6272 return false; 6273 6274 // Compute the value which the bitfield will contain. 6275 llvm::APSInt TruncatedValue = Value.trunc(FieldWidth); 6276 TruncatedValue.setIsSigned(Bitfield->getType()->isSignedIntegerType()); 6277 6278 // Check whether the stored value is equal to the original value. 6279 TruncatedValue = TruncatedValue.extend(OriginalWidth); 6280 if (llvm::APSInt::isSameValue(Value, TruncatedValue)) 6281 return false; 6282 6283 // Special-case bitfields of width 1: booleans are naturally 0/1, and 6284 // therefore don't strictly fit into a signed bitfield of width 1. 6285 if (FieldWidth == 1 && Value == 1) 6286 return false; 6287 6288 std::string PrettyValue = Value.toString(10); 6289 std::string PrettyTrunc = TruncatedValue.toString(10); 6290 6291 S.Diag(InitLoc, diag::warn_impcast_bitfield_precision_constant) 6292 << PrettyValue << PrettyTrunc << OriginalInit->getType() 6293 << Init->getSourceRange(); 6294 6295 return true; 6296 } 6297 6298 /// Analyze the given simple or compound assignment for warning-worthy 6299 /// operations. 6300 static void AnalyzeAssignment(Sema &S, BinaryOperator *E) { 6301 // Just recurse on the LHS. 6302 AnalyzeImplicitConversions(S, E->getLHS(), E->getOperatorLoc()); 6303 6304 // We want to recurse on the RHS as normal unless we're assigning to 6305 // a bitfield. 6306 if (FieldDecl *Bitfield = E->getLHS()->getSourceBitField()) { 6307 if (AnalyzeBitFieldAssignment(S, Bitfield, E->getRHS(), 6308 E->getOperatorLoc())) { 6309 // Recurse, ignoring any implicit conversions on the RHS. 6310 return AnalyzeImplicitConversions(S, E->getRHS()->IgnoreParenImpCasts(), 6311 E->getOperatorLoc()); 6312 } 6313 } 6314 6315 AnalyzeImplicitConversions(S, E->getRHS(), E->getOperatorLoc()); 6316 } 6317 6318 /// Diagnose an implicit cast; purely a helper for CheckImplicitConversion. 6319 static void DiagnoseImpCast(Sema &S, Expr *E, QualType SourceType, QualType T, 6320 SourceLocation CContext, unsigned diag, 6321 bool pruneControlFlow = false) { 6322 if (pruneControlFlow) { 6323 S.DiagRuntimeBehavior(E->getExprLoc(), E, 6324 S.PDiag(diag) 6325 << SourceType << T << E->getSourceRange() 6326 << SourceRange(CContext)); 6327 return; 6328 } 6329 S.Diag(E->getExprLoc(), diag) 6330 << SourceType << T << E->getSourceRange() << SourceRange(CContext); 6331 } 6332 6333 /// Diagnose an implicit cast; purely a helper for CheckImplicitConversion. 6334 static void DiagnoseImpCast(Sema &S, Expr *E, QualType T, 6335 SourceLocation CContext, unsigned diag, 6336 bool pruneControlFlow = false) { 6337 DiagnoseImpCast(S, E, E->getType(), T, CContext, diag, pruneControlFlow); 6338 } 6339 6340 /// Diagnose an implicit cast from a literal expression. Does not warn when the 6341 /// cast wouldn't lose information. 6342 void DiagnoseFloatingLiteralImpCast(Sema &S, FloatingLiteral *FL, QualType T, 6343 SourceLocation CContext) { 6344 // Try to convert the literal exactly to an integer. If we can, don't warn. 6345 bool isExact = false; 6346 const llvm::APFloat &Value = FL->getValue(); 6347 llvm::APSInt IntegerValue(S.Context.getIntWidth(T), 6348 T->hasUnsignedIntegerRepresentation()); 6349 if (Value.convertToInteger(IntegerValue, 6350 llvm::APFloat::rmTowardZero, &isExact) 6351 == llvm::APFloat::opOK && isExact) 6352 return; 6353 6354 // FIXME: Force the precision of the source value down so we don't print 6355 // digits which are usually useless (we don't really care here if we 6356 // truncate a digit by accident in edge cases). Ideally, APFloat::toString 6357 // would automatically print the shortest representation, but it's a bit 6358 // tricky to implement. 6359 SmallString<16> PrettySourceValue; 6360 unsigned precision = llvm::APFloat::semanticsPrecision(Value.getSemantics()); 6361 precision = (precision * 59 + 195) / 196; 6362 Value.toString(PrettySourceValue, precision); 6363 6364 SmallString<16> PrettyTargetValue; 6365 if (T->isSpecificBuiltinType(BuiltinType::Bool)) 6366 PrettyTargetValue = IntegerValue == 0 ? "false" : "true"; 6367 else 6368 IntegerValue.toString(PrettyTargetValue); 6369 6370 S.Diag(FL->getExprLoc(), diag::warn_impcast_literal_float_to_integer) 6371 << FL->getType() << T.getUnqualifiedType() << PrettySourceValue 6372 << PrettyTargetValue << FL->getSourceRange() << SourceRange(CContext); 6373 } 6374 6375 std::string PrettyPrintInRange(const llvm::APSInt &Value, IntRange Range) { 6376 if (!Range.Width) return "0"; 6377 6378 llvm::APSInt ValueInRange = Value; 6379 ValueInRange.setIsSigned(!Range.NonNegative); 6380 ValueInRange = ValueInRange.trunc(Range.Width); 6381 return ValueInRange.toString(10); 6382 } 6383 6384 static bool IsImplicitBoolFloatConversion(Sema &S, Expr *Ex, bool ToBool) { 6385 if (!isa<ImplicitCastExpr>(Ex)) 6386 return false; 6387 6388 Expr *InnerE = Ex->IgnoreParenImpCasts(); 6389 const Type *Target = S.Context.getCanonicalType(Ex->getType()).getTypePtr(); 6390 const Type *Source = 6391 S.Context.getCanonicalType(InnerE->getType()).getTypePtr(); 6392 if (Target->isDependentType()) 6393 return false; 6394 6395 const BuiltinType *FloatCandidateBT = 6396 dyn_cast<BuiltinType>(ToBool ? Source : Target); 6397 const Type *BoolCandidateType = ToBool ? Target : Source; 6398 6399 return (BoolCandidateType->isSpecificBuiltinType(BuiltinType::Bool) && 6400 FloatCandidateBT && (FloatCandidateBT->isFloatingPoint())); 6401 } 6402 6403 void CheckImplicitArgumentConversions(Sema &S, CallExpr *TheCall, 6404 SourceLocation CC) { 6405 unsigned NumArgs = TheCall->getNumArgs(); 6406 for (unsigned i = 0; i < NumArgs; ++i) { 6407 Expr *CurrA = TheCall->getArg(i); 6408 if (!IsImplicitBoolFloatConversion(S, CurrA, true)) 6409 continue; 6410 6411 bool IsSwapped = ((i > 0) && 6412 IsImplicitBoolFloatConversion(S, TheCall->getArg(i - 1), false)); 6413 IsSwapped |= ((i < (NumArgs - 1)) && 6414 IsImplicitBoolFloatConversion(S, TheCall->getArg(i + 1), false)); 6415 if (IsSwapped) { 6416 // Warn on this floating-point to bool conversion. 6417 DiagnoseImpCast(S, CurrA->IgnoreParenImpCasts(), 6418 CurrA->getType(), CC, 6419 diag::warn_impcast_floating_point_to_bool); 6420 } 6421 } 6422 } 6423 6424 static void DiagnoseNullConversion(Sema &S, Expr *E, QualType T, 6425 SourceLocation CC) { 6426 if (S.Diags.isIgnored(diag::warn_impcast_null_pointer_to_integer, 6427 E->getExprLoc())) 6428 return; 6429 6430 // Check for NULL (GNUNull) or nullptr (CXX11_nullptr). 6431 const Expr::NullPointerConstantKind NullKind = 6432 E->isNullPointerConstant(S.Context, Expr::NPC_ValueDependentIsNotNull); 6433 if (NullKind != Expr::NPCK_GNUNull && NullKind != Expr::NPCK_CXX11_nullptr) 6434 return; 6435 6436 // Return if target type is a safe conversion. 6437 if (T->isAnyPointerType() || T->isBlockPointerType() || 6438 T->isMemberPointerType() || !T->isScalarType() || T->isNullPtrType()) 6439 return; 6440 6441 SourceLocation Loc = E->getSourceRange().getBegin(); 6442 6443 // __null is usually wrapped in a macro. Go up a macro if that is the case. 6444 if (NullKind == Expr::NPCK_GNUNull) { 6445 if (Loc.isMacroID()) 6446 Loc = S.SourceMgr.getImmediateExpansionRange(Loc).first; 6447 } 6448 6449 // Only warn if the null and context location are in the same macro expansion. 6450 if (S.SourceMgr.getFileID(Loc) != S.SourceMgr.getFileID(CC)) 6451 return; 6452 6453 S.Diag(Loc, diag::warn_impcast_null_pointer_to_integer) 6454 << (NullKind == Expr::NPCK_CXX11_nullptr) << T << clang::SourceRange(CC) 6455 << FixItHint::CreateReplacement(Loc, 6456 S.getFixItZeroLiteralForType(T, Loc)); 6457 } 6458 6459 void CheckImplicitConversion(Sema &S, Expr *E, QualType T, 6460 SourceLocation CC, bool *ICContext = nullptr) { 6461 if (E->isTypeDependent() || E->isValueDependent()) return; 6462 6463 const Type *Source = S.Context.getCanonicalType(E->getType()).getTypePtr(); 6464 const Type *Target = S.Context.getCanonicalType(T).getTypePtr(); 6465 if (Source == Target) return; 6466 if (Target->isDependentType()) return; 6467 6468 // If the conversion context location is invalid don't complain. We also 6469 // don't want to emit a warning if the issue occurs from the expansion of 6470 // a system macro. The problem is that 'getSpellingLoc()' is slow, so we 6471 // delay this check as long as possible. Once we detect we are in that 6472 // scenario, we just return. 6473 if (CC.isInvalid()) 6474 return; 6475 6476 // Diagnose implicit casts to bool. 6477 if (Target->isSpecificBuiltinType(BuiltinType::Bool)) { 6478 if (isa<StringLiteral>(E)) 6479 // Warn on string literal to bool. Checks for string literals in logical 6480 // and expressions, for instance, assert(0 && "error here"), are 6481 // prevented by a check in AnalyzeImplicitConversions(). 6482 return DiagnoseImpCast(S, E, T, CC, 6483 diag::warn_impcast_string_literal_to_bool); 6484 if (isa<ObjCStringLiteral>(E) || isa<ObjCArrayLiteral>(E) || 6485 isa<ObjCDictionaryLiteral>(E) || isa<ObjCBoxedExpr>(E)) { 6486 // This covers the literal expressions that evaluate to Objective-C 6487 // objects. 6488 return DiagnoseImpCast(S, E, T, CC, 6489 diag::warn_impcast_objective_c_literal_to_bool); 6490 } 6491 if (Source->isPointerType() || Source->canDecayToPointerType()) { 6492 // Warn on pointer to bool conversion that is always true. 6493 S.DiagnoseAlwaysNonNullPointer(E, Expr::NPCK_NotNull, /*IsEqual*/ false, 6494 SourceRange(CC)); 6495 } 6496 } 6497 6498 // Strip vector types. 6499 if (isa<VectorType>(Source)) { 6500 if (!isa<VectorType>(Target)) { 6501 if (S.SourceMgr.isInSystemMacro(CC)) 6502 return; 6503 return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_vector_scalar); 6504 } 6505 6506 // If the vector cast is cast between two vectors of the same size, it is 6507 // a bitcast, not a conversion. 6508 if (S.Context.getTypeSize(Source) == S.Context.getTypeSize(Target)) 6509 return; 6510 6511 Source = cast<VectorType>(Source)->getElementType().getTypePtr(); 6512 Target = cast<VectorType>(Target)->getElementType().getTypePtr(); 6513 } 6514 if (auto VecTy = dyn_cast<VectorType>(Target)) 6515 Target = VecTy->getElementType().getTypePtr(); 6516 6517 // Strip complex types. 6518 if (isa<ComplexType>(Source)) { 6519 if (!isa<ComplexType>(Target)) { 6520 if (S.SourceMgr.isInSystemMacro(CC)) 6521 return; 6522 6523 return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_complex_scalar); 6524 } 6525 6526 Source = cast<ComplexType>(Source)->getElementType().getTypePtr(); 6527 Target = cast<ComplexType>(Target)->getElementType().getTypePtr(); 6528 } 6529 6530 const BuiltinType *SourceBT = dyn_cast<BuiltinType>(Source); 6531 const BuiltinType *TargetBT = dyn_cast<BuiltinType>(Target); 6532 6533 // If the source is floating point... 6534 if (SourceBT && SourceBT->isFloatingPoint()) { 6535 // ...and the target is floating point... 6536 if (TargetBT && TargetBT->isFloatingPoint()) { 6537 // ...then warn if we're dropping FP rank. 6538 6539 // Builtin FP kinds are ordered by increasing FP rank. 6540 if (SourceBT->getKind() > TargetBT->getKind()) { 6541 // Don't warn about float constants that are precisely 6542 // representable in the target type. 6543 Expr::EvalResult result; 6544 if (E->EvaluateAsRValue(result, S.Context)) { 6545 // Value might be a float, a float vector, or a float complex. 6546 if (IsSameFloatAfterCast(result.Val, 6547 S.Context.getFloatTypeSemantics(QualType(TargetBT, 0)), 6548 S.Context.getFloatTypeSemantics(QualType(SourceBT, 0)))) 6549 return; 6550 } 6551 6552 if (S.SourceMgr.isInSystemMacro(CC)) 6553 return; 6554 6555 DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_float_precision); 6556 } 6557 return; 6558 } 6559 6560 // If the target is integral, always warn. 6561 if (TargetBT && TargetBT->isInteger()) { 6562 if (S.SourceMgr.isInSystemMacro(CC)) 6563 return; 6564 6565 Expr *InnerE = E->IgnoreParenImpCasts(); 6566 // We also want to warn on, e.g., "int i = -1.234" 6567 if (UnaryOperator *UOp = dyn_cast<UnaryOperator>(InnerE)) 6568 if (UOp->getOpcode() == UO_Minus || UOp->getOpcode() == UO_Plus) 6569 InnerE = UOp->getSubExpr()->IgnoreParenImpCasts(); 6570 6571 if (FloatingLiteral *FL = dyn_cast<FloatingLiteral>(InnerE)) { 6572 DiagnoseFloatingLiteralImpCast(S, FL, T, CC); 6573 } else { 6574 DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_float_integer); 6575 } 6576 } 6577 6578 // If the target is bool, warn if expr is a function or method call. 6579 if (Target->isSpecificBuiltinType(BuiltinType::Bool) && 6580 isa<CallExpr>(E)) { 6581 // Check last argument of function call to see if it is an 6582 // implicit cast from a type matching the type the result 6583 // is being cast to. 6584 CallExpr *CEx = cast<CallExpr>(E); 6585 unsigned NumArgs = CEx->getNumArgs(); 6586 if (NumArgs > 0) { 6587 Expr *LastA = CEx->getArg(NumArgs - 1); 6588 Expr *InnerE = LastA->IgnoreParenImpCasts(); 6589 const Type *InnerType = 6590 S.Context.getCanonicalType(InnerE->getType()).getTypePtr(); 6591 if (isa<ImplicitCastExpr>(LastA) && (InnerType == Target)) { 6592 // Warn on this floating-point to bool conversion 6593 DiagnoseImpCast(S, E, T, CC, 6594 diag::warn_impcast_floating_point_to_bool); 6595 } 6596 } 6597 } 6598 return; 6599 } 6600 6601 DiagnoseNullConversion(S, E, T, CC); 6602 6603 if (!Source->isIntegerType() || !Target->isIntegerType()) 6604 return; 6605 6606 // TODO: remove this early return once the false positives for constant->bool 6607 // in templates, macros, etc, are reduced or removed. 6608 if (Target->isSpecificBuiltinType(BuiltinType::Bool)) 6609 return; 6610 6611 IntRange SourceRange = GetExprRange(S.Context, E); 6612 IntRange TargetRange = IntRange::forTargetOfCanonicalType(S.Context, Target); 6613 6614 if (SourceRange.Width > TargetRange.Width) { 6615 // If the source is a constant, use a default-on diagnostic. 6616 // TODO: this should happen for bitfield stores, too. 6617 llvm::APSInt Value(32); 6618 if (E->isIntegerConstantExpr(Value, S.Context)) { 6619 if (S.SourceMgr.isInSystemMacro(CC)) 6620 return; 6621 6622 std::string PrettySourceValue = Value.toString(10); 6623 std::string PrettyTargetValue = PrettyPrintInRange(Value, TargetRange); 6624 6625 S.DiagRuntimeBehavior(E->getExprLoc(), E, 6626 S.PDiag(diag::warn_impcast_integer_precision_constant) 6627 << PrettySourceValue << PrettyTargetValue 6628 << E->getType() << T << E->getSourceRange() 6629 << clang::SourceRange(CC)); 6630 return; 6631 } 6632 6633 // People want to build with -Wshorten-64-to-32 and not -Wconversion. 6634 if (S.SourceMgr.isInSystemMacro(CC)) 6635 return; 6636 6637 if (TargetRange.Width == 32 && S.Context.getIntWidth(E->getType()) == 64) 6638 return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_integer_64_32, 6639 /* pruneControlFlow */ true); 6640 return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_integer_precision); 6641 } 6642 6643 if ((TargetRange.NonNegative && !SourceRange.NonNegative) || 6644 (!TargetRange.NonNegative && SourceRange.NonNegative && 6645 SourceRange.Width == TargetRange.Width)) { 6646 6647 if (S.SourceMgr.isInSystemMacro(CC)) 6648 return; 6649 6650 unsigned DiagID = diag::warn_impcast_integer_sign; 6651 6652 // Traditionally, gcc has warned about this under -Wsign-compare. 6653 // We also want to warn about it in -Wconversion. 6654 // So if -Wconversion is off, use a completely identical diagnostic 6655 // in the sign-compare group. 6656 // The conditional-checking code will 6657 if (ICContext) { 6658 DiagID = diag::warn_impcast_integer_sign_conditional; 6659 *ICContext = true; 6660 } 6661 6662 return DiagnoseImpCast(S, E, T, CC, DiagID); 6663 } 6664 6665 // Diagnose conversions between different enumeration types. 6666 // In C, we pretend that the type of an EnumConstantDecl is its enumeration 6667 // type, to give us better diagnostics. 6668 QualType SourceType = E->getType(); 6669 if (!S.getLangOpts().CPlusPlus) { 6670 if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) 6671 if (EnumConstantDecl *ECD = dyn_cast<EnumConstantDecl>(DRE->getDecl())) { 6672 EnumDecl *Enum = cast<EnumDecl>(ECD->getDeclContext()); 6673 SourceType = S.Context.getTypeDeclType(Enum); 6674 Source = S.Context.getCanonicalType(SourceType).getTypePtr(); 6675 } 6676 } 6677 6678 if (const EnumType *SourceEnum = Source->getAs<EnumType>()) 6679 if (const EnumType *TargetEnum = Target->getAs<EnumType>()) 6680 if (SourceEnum->getDecl()->hasNameForLinkage() && 6681 TargetEnum->getDecl()->hasNameForLinkage() && 6682 SourceEnum != TargetEnum) { 6683 if (S.SourceMgr.isInSystemMacro(CC)) 6684 return; 6685 6686 return DiagnoseImpCast(S, E, SourceType, T, CC, 6687 diag::warn_impcast_different_enum_types); 6688 } 6689 6690 return; 6691 } 6692 6693 void CheckConditionalOperator(Sema &S, ConditionalOperator *E, 6694 SourceLocation CC, QualType T); 6695 6696 void CheckConditionalOperand(Sema &S, Expr *E, QualType T, 6697 SourceLocation CC, bool &ICContext) { 6698 E = E->IgnoreParenImpCasts(); 6699 6700 if (isa<ConditionalOperator>(E)) 6701 return CheckConditionalOperator(S, cast<ConditionalOperator>(E), CC, T); 6702 6703 AnalyzeImplicitConversions(S, E, CC); 6704 if (E->getType() != T) 6705 return CheckImplicitConversion(S, E, T, CC, &ICContext); 6706 return; 6707 } 6708 6709 void CheckConditionalOperator(Sema &S, ConditionalOperator *E, 6710 SourceLocation CC, QualType T) { 6711 AnalyzeImplicitConversions(S, E->getCond(), E->getQuestionLoc()); 6712 6713 bool Suspicious = false; 6714 CheckConditionalOperand(S, E->getTrueExpr(), T, CC, Suspicious); 6715 CheckConditionalOperand(S, E->getFalseExpr(), T, CC, Suspicious); 6716 6717 // If -Wconversion would have warned about either of the candidates 6718 // for a signedness conversion to the context type... 6719 if (!Suspicious) return; 6720 6721 // ...but it's currently ignored... 6722 if (!S.Diags.isIgnored(diag::warn_impcast_integer_sign_conditional, CC)) 6723 return; 6724 6725 // ...then check whether it would have warned about either of the 6726 // candidates for a signedness conversion to the condition type. 6727 if (E->getType() == T) return; 6728 6729 Suspicious = false; 6730 CheckImplicitConversion(S, E->getTrueExpr()->IgnoreParenImpCasts(), 6731 E->getType(), CC, &Suspicious); 6732 if (!Suspicious) 6733 CheckImplicitConversion(S, E->getFalseExpr()->IgnoreParenImpCasts(), 6734 E->getType(), CC, &Suspicious); 6735 } 6736 6737 /// CheckBoolLikeConversion - Check conversion of given expression to boolean. 6738 /// Input argument E is a logical expression. 6739 static void CheckBoolLikeConversion(Sema &S, Expr *E, SourceLocation CC) { 6740 if (S.getLangOpts().Bool) 6741 return; 6742 CheckImplicitConversion(S, E->IgnoreParenImpCasts(), S.Context.BoolTy, CC); 6743 } 6744 6745 /// AnalyzeImplicitConversions - Find and report any interesting 6746 /// implicit conversions in the given expression. There are a couple 6747 /// of competing diagnostics here, -Wconversion and -Wsign-compare. 6748 void AnalyzeImplicitConversions(Sema &S, Expr *OrigE, SourceLocation CC) { 6749 QualType T = OrigE->getType(); 6750 Expr *E = OrigE->IgnoreParenImpCasts(); 6751 6752 if (E->isTypeDependent() || E->isValueDependent()) 6753 return; 6754 6755 // For conditional operators, we analyze the arguments as if they 6756 // were being fed directly into the output. 6757 if (isa<ConditionalOperator>(E)) { 6758 ConditionalOperator *CO = cast<ConditionalOperator>(E); 6759 CheckConditionalOperator(S, CO, CC, T); 6760 return; 6761 } 6762 6763 // Check implicit argument conversions for function calls. 6764 if (CallExpr *Call = dyn_cast<CallExpr>(E)) 6765 CheckImplicitArgumentConversions(S, Call, CC); 6766 6767 // Go ahead and check any implicit conversions we might have skipped. 6768 // The non-canonical typecheck is just an optimization; 6769 // CheckImplicitConversion will filter out dead implicit conversions. 6770 if (E->getType() != T) 6771 CheckImplicitConversion(S, E, T, CC); 6772 6773 // Now continue drilling into this expression. 6774 6775 if (PseudoObjectExpr * POE = dyn_cast<PseudoObjectExpr>(E)) { 6776 if (POE->getResultExpr()) 6777 E = POE->getResultExpr(); 6778 } 6779 6780 if (const OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(E)) 6781 return AnalyzeImplicitConversions(S, OVE->getSourceExpr(), CC); 6782 6783 // Skip past explicit casts. 6784 if (isa<ExplicitCastExpr>(E)) { 6785 E = cast<ExplicitCastExpr>(E)->getSubExpr()->IgnoreParenImpCasts(); 6786 return AnalyzeImplicitConversions(S, E, CC); 6787 } 6788 6789 if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) { 6790 // Do a somewhat different check with comparison operators. 6791 if (BO->isComparisonOp()) 6792 return AnalyzeComparison(S, BO); 6793 6794 // And with simple assignments. 6795 if (BO->getOpcode() == BO_Assign) 6796 return AnalyzeAssignment(S, BO); 6797 } 6798 6799 // These break the otherwise-useful invariant below. Fortunately, 6800 // we don't really need to recurse into them, because any internal 6801 // expressions should have been analyzed already when they were 6802 // built into statements. 6803 if (isa<StmtExpr>(E)) return; 6804 6805 // Don't descend into unevaluated contexts. 6806 if (isa<UnaryExprOrTypeTraitExpr>(E)) return; 6807 6808 // Now just recurse over the expression's children. 6809 CC = E->getExprLoc(); 6810 BinaryOperator *BO = dyn_cast<BinaryOperator>(E); 6811 bool IsLogicalAndOperator = BO && BO->getOpcode() == BO_LAnd; 6812 for (Stmt::child_range I = E->children(); I; ++I) { 6813 Expr *ChildExpr = dyn_cast_or_null<Expr>(*I); 6814 if (!ChildExpr) 6815 continue; 6816 6817 if (IsLogicalAndOperator && 6818 isa<StringLiteral>(ChildExpr->IgnoreParenImpCasts())) 6819 // Ignore checking string literals that are in logical and operators. 6820 // This is a common pattern for asserts. 6821 continue; 6822 AnalyzeImplicitConversions(S, ChildExpr, CC); 6823 } 6824 6825 if (BO && BO->isLogicalOp()) { 6826 Expr *SubExpr = BO->getLHS()->IgnoreParenImpCasts(); 6827 if (!IsLogicalAndOperator || !isa<StringLiteral>(SubExpr)) 6828 ::CheckBoolLikeConversion(S, SubExpr, BO->getExprLoc()); 6829 6830 SubExpr = BO->getRHS()->IgnoreParenImpCasts(); 6831 if (!IsLogicalAndOperator || !isa<StringLiteral>(SubExpr)) 6832 ::CheckBoolLikeConversion(S, SubExpr, BO->getExprLoc()); 6833 } 6834 6835 if (const UnaryOperator *U = dyn_cast<UnaryOperator>(E)) 6836 if (U->getOpcode() == UO_LNot) 6837 ::CheckBoolLikeConversion(S, U->getSubExpr(), CC); 6838 } 6839 6840 } // end anonymous namespace 6841 6842 enum { 6843 AddressOf, 6844 FunctionPointer, 6845 ArrayPointer 6846 }; 6847 6848 // Helper function for Sema::DiagnoseAlwaysNonNullPointer. 6849 // Returns true when emitting a warning about taking the address of a reference. 6850 static bool CheckForReference(Sema &SemaRef, const Expr *E, 6851 PartialDiagnostic PD) { 6852 E = E->IgnoreParenImpCasts(); 6853 6854 const FunctionDecl *FD = nullptr; 6855 6856 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) { 6857 if (!DRE->getDecl()->getType()->isReferenceType()) 6858 return false; 6859 } else if (const MemberExpr *M = dyn_cast<MemberExpr>(E)) { 6860 if (!M->getMemberDecl()->getType()->isReferenceType()) 6861 return false; 6862 } else if (const CallExpr *Call = dyn_cast<CallExpr>(E)) { 6863 if (!Call->getCallReturnType(SemaRef.Context)->isReferenceType()) 6864 return false; 6865 FD = Call->getDirectCallee(); 6866 } else { 6867 return false; 6868 } 6869 6870 SemaRef.Diag(E->getExprLoc(), PD); 6871 6872 // If possible, point to location of function. 6873 if (FD) { 6874 SemaRef.Diag(FD->getLocation(), diag::note_reference_is_return_value) << FD; 6875 } 6876 6877 return true; 6878 } 6879 6880 // Returns true if the SourceLocation is expanded from any macro body. 6881 // Returns false if the SourceLocation is invalid, is from not in a macro 6882 // expansion, or is from expanded from a top-level macro argument. 6883 static bool IsInAnyMacroBody(const SourceManager &SM, SourceLocation Loc) { 6884 if (Loc.isInvalid()) 6885 return false; 6886 6887 while (Loc.isMacroID()) { 6888 if (SM.isMacroBodyExpansion(Loc)) 6889 return true; 6890 Loc = SM.getImmediateMacroCallerLoc(Loc); 6891 } 6892 6893 return false; 6894 } 6895 6896 /// \brief Diagnose pointers that are always non-null. 6897 /// \param E the expression containing the pointer 6898 /// \param NullKind NPCK_NotNull if E is a cast to bool, otherwise, E is 6899 /// compared to a null pointer 6900 /// \param IsEqual True when the comparison is equal to a null pointer 6901 /// \param Range Extra SourceRange to highlight in the diagnostic 6902 void Sema::DiagnoseAlwaysNonNullPointer(Expr *E, 6903 Expr::NullPointerConstantKind NullKind, 6904 bool IsEqual, SourceRange Range) { 6905 if (!E) 6906 return; 6907 6908 // Don't warn inside macros. 6909 if (E->getExprLoc().isMacroID()) { 6910 const SourceManager &SM = getSourceManager(); 6911 if (IsInAnyMacroBody(SM, E->getExprLoc()) || 6912 IsInAnyMacroBody(SM, Range.getBegin())) 6913 return; 6914 } 6915 E = E->IgnoreImpCasts(); 6916 6917 const bool IsCompare = NullKind != Expr::NPCK_NotNull; 6918 6919 if (isa<CXXThisExpr>(E)) { 6920 unsigned DiagID = IsCompare ? diag::warn_this_null_compare 6921 : diag::warn_this_bool_conversion; 6922 Diag(E->getExprLoc(), DiagID) << E->getSourceRange() << Range << IsEqual; 6923 return; 6924 } 6925 6926 bool IsAddressOf = false; 6927 6928 if (UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) { 6929 if (UO->getOpcode() != UO_AddrOf) 6930 return; 6931 IsAddressOf = true; 6932 E = UO->getSubExpr(); 6933 } 6934 6935 if (IsAddressOf) { 6936 unsigned DiagID = IsCompare 6937 ? diag::warn_address_of_reference_null_compare 6938 : diag::warn_address_of_reference_bool_conversion; 6939 PartialDiagnostic PD = PDiag(DiagID) << E->getSourceRange() << Range 6940 << IsEqual; 6941 if (CheckForReference(*this, E, PD)) { 6942 return; 6943 } 6944 } 6945 6946 // Expect to find a single Decl. Skip anything more complicated. 6947 ValueDecl *D = nullptr; 6948 if (DeclRefExpr *R = dyn_cast<DeclRefExpr>(E)) { 6949 D = R->getDecl(); 6950 } else if (MemberExpr *M = dyn_cast<MemberExpr>(E)) { 6951 D = M->getMemberDecl(); 6952 } 6953 6954 // Weak Decls can be null. 6955 if (!D || D->isWeak()) 6956 return; 6957 6958 // Check for parameter decl with nonnull attribute 6959 if (const ParmVarDecl* PV = dyn_cast<ParmVarDecl>(D)) { 6960 if (getCurFunction() && !getCurFunction()->ModifiedNonNullParams.count(PV)) 6961 if (const FunctionDecl* FD = dyn_cast<FunctionDecl>(PV->getDeclContext())) { 6962 unsigned NumArgs = FD->getNumParams(); 6963 llvm::SmallBitVector AttrNonNull(NumArgs); 6964 for (const auto *NonNull : FD->specific_attrs<NonNullAttr>()) { 6965 if (!NonNull->args_size()) { 6966 AttrNonNull.set(0, NumArgs); 6967 break; 6968 } 6969 for (unsigned Val : NonNull->args()) { 6970 if (Val >= NumArgs) 6971 continue; 6972 AttrNonNull.set(Val); 6973 } 6974 } 6975 if (!AttrNonNull.empty()) 6976 for (unsigned i = 0; i < NumArgs; ++i) 6977 if (FD->getParamDecl(i) == PV && 6978 (AttrNonNull[i] || PV->hasAttr<NonNullAttr>())) { 6979 std::string Str; 6980 llvm::raw_string_ostream S(Str); 6981 E->printPretty(S, nullptr, getPrintingPolicy()); 6982 unsigned DiagID = IsCompare ? diag::warn_nonnull_parameter_compare 6983 : diag::warn_cast_nonnull_to_bool; 6984 Diag(E->getExprLoc(), DiagID) << S.str() << E->getSourceRange() 6985 << Range << IsEqual; 6986 return; 6987 } 6988 } 6989 } 6990 6991 QualType T = D->getType(); 6992 const bool IsArray = T->isArrayType(); 6993 const bool IsFunction = T->isFunctionType(); 6994 6995 // Address of function is used to silence the function warning. 6996 if (IsAddressOf && IsFunction) { 6997 return; 6998 } 6999 7000 // Found nothing. 7001 if (!IsAddressOf && !IsFunction && !IsArray) 7002 return; 7003 7004 // Pretty print the expression for the diagnostic. 7005 std::string Str; 7006 llvm::raw_string_ostream S(Str); 7007 E->printPretty(S, nullptr, getPrintingPolicy()); 7008 7009 unsigned DiagID = IsCompare ? diag::warn_null_pointer_compare 7010 : diag::warn_impcast_pointer_to_bool; 7011 unsigned DiagType; 7012 if (IsAddressOf) 7013 DiagType = AddressOf; 7014 else if (IsFunction) 7015 DiagType = FunctionPointer; 7016 else if (IsArray) 7017 DiagType = ArrayPointer; 7018 else 7019 llvm_unreachable("Could not determine diagnostic."); 7020 Diag(E->getExprLoc(), DiagID) << DiagType << S.str() << E->getSourceRange() 7021 << Range << IsEqual; 7022 7023 if (!IsFunction) 7024 return; 7025 7026 // Suggest '&' to silence the function warning. 7027 Diag(E->getExprLoc(), diag::note_function_warning_silence) 7028 << FixItHint::CreateInsertion(E->getLocStart(), "&"); 7029 7030 // Check to see if '()' fixit should be emitted. 7031 QualType ReturnType; 7032 UnresolvedSet<4> NonTemplateOverloads; 7033 tryExprAsCall(*E, ReturnType, NonTemplateOverloads); 7034 if (ReturnType.isNull()) 7035 return; 7036 7037 if (IsCompare) { 7038 // There are two cases here. If there is null constant, the only suggest 7039 // for a pointer return type. If the null is 0, then suggest if the return 7040 // type is a pointer or an integer type. 7041 if (!ReturnType->isPointerType()) { 7042 if (NullKind == Expr::NPCK_ZeroExpression || 7043 NullKind == Expr::NPCK_ZeroLiteral) { 7044 if (!ReturnType->isIntegerType()) 7045 return; 7046 } else { 7047 return; 7048 } 7049 } 7050 } else { // !IsCompare 7051 // For function to bool, only suggest if the function pointer has bool 7052 // return type. 7053 if (!ReturnType->isSpecificBuiltinType(BuiltinType::Bool)) 7054 return; 7055 } 7056 Diag(E->getExprLoc(), diag::note_function_to_function_call) 7057 << FixItHint::CreateInsertion(getLocForEndOfToken(E->getLocEnd()), "()"); 7058 } 7059 7060 7061 /// Diagnoses "dangerous" implicit conversions within the given 7062 /// expression (which is a full expression). Implements -Wconversion 7063 /// and -Wsign-compare. 7064 /// 7065 /// \param CC the "context" location of the implicit conversion, i.e. 7066 /// the most location of the syntactic entity requiring the implicit 7067 /// conversion 7068 void Sema::CheckImplicitConversions(Expr *E, SourceLocation CC) { 7069 // Don't diagnose in unevaluated contexts. 7070 if (isUnevaluatedContext()) 7071 return; 7072 7073 // Don't diagnose for value- or type-dependent expressions. 7074 if (E->isTypeDependent() || E->isValueDependent()) 7075 return; 7076 7077 // Check for array bounds violations in cases where the check isn't triggered 7078 // elsewhere for other Expr types (like BinaryOperators), e.g. when an 7079 // ArraySubscriptExpr is on the RHS of a variable initialization. 7080 CheckArrayAccess(E); 7081 7082 // This is not the right CC for (e.g.) a variable initialization. 7083 AnalyzeImplicitConversions(*this, E, CC); 7084 } 7085 7086 /// CheckBoolLikeConversion - Check conversion of given expression to boolean. 7087 /// Input argument E is a logical expression. 7088 void Sema::CheckBoolLikeConversion(Expr *E, SourceLocation CC) { 7089 ::CheckBoolLikeConversion(*this, E, CC); 7090 } 7091 7092 /// Diagnose when expression is an integer constant expression and its evaluation 7093 /// results in integer overflow 7094 void Sema::CheckForIntOverflow (Expr *E) { 7095 if (isa<BinaryOperator>(E->IgnoreParenCasts())) 7096 E->IgnoreParenCasts()->EvaluateForOverflow(Context); 7097 } 7098 7099 namespace { 7100 /// \brief Visitor for expressions which looks for unsequenced operations on the 7101 /// same object. 7102 class SequenceChecker : public EvaluatedExprVisitor<SequenceChecker> { 7103 typedef EvaluatedExprVisitor<SequenceChecker> Base; 7104 7105 /// \brief A tree of sequenced regions within an expression. Two regions are 7106 /// unsequenced if one is an ancestor or a descendent of the other. When we 7107 /// finish processing an expression with sequencing, such as a comma 7108 /// expression, we fold its tree nodes into its parent, since they are 7109 /// unsequenced with respect to nodes we will visit later. 7110 class SequenceTree { 7111 struct Value { 7112 explicit Value(unsigned Parent) : Parent(Parent), Merged(false) {} 7113 unsigned Parent : 31; 7114 bool Merged : 1; 7115 }; 7116 SmallVector<Value, 8> Values; 7117 7118 public: 7119 /// \brief A region within an expression which may be sequenced with respect 7120 /// to some other region. 7121 class Seq { 7122 explicit Seq(unsigned N) : Index(N) {} 7123 unsigned Index; 7124 friend class SequenceTree; 7125 public: 7126 Seq() : Index(0) {} 7127 }; 7128 7129 SequenceTree() { Values.push_back(Value(0)); } 7130 Seq root() const { return Seq(0); } 7131 7132 /// \brief Create a new sequence of operations, which is an unsequenced 7133 /// subset of \p Parent. This sequence of operations is sequenced with 7134 /// respect to other children of \p Parent. 7135 Seq allocate(Seq Parent) { 7136 Values.push_back(Value(Parent.Index)); 7137 return Seq(Values.size() - 1); 7138 } 7139 7140 /// \brief Merge a sequence of operations into its parent. 7141 void merge(Seq S) { 7142 Values[S.Index].Merged = true; 7143 } 7144 7145 /// \brief Determine whether two operations are unsequenced. This operation 7146 /// is asymmetric: \p Cur should be the more recent sequence, and \p Old 7147 /// should have been merged into its parent as appropriate. 7148 bool isUnsequenced(Seq Cur, Seq Old) { 7149 unsigned C = representative(Cur.Index); 7150 unsigned Target = representative(Old.Index); 7151 while (C >= Target) { 7152 if (C == Target) 7153 return true; 7154 C = Values[C].Parent; 7155 } 7156 return false; 7157 } 7158 7159 private: 7160 /// \brief Pick a representative for a sequence. 7161 unsigned representative(unsigned K) { 7162 if (Values[K].Merged) 7163 // Perform path compression as we go. 7164 return Values[K].Parent = representative(Values[K].Parent); 7165 return K; 7166 } 7167 }; 7168 7169 /// An object for which we can track unsequenced uses. 7170 typedef NamedDecl *Object; 7171 7172 /// Different flavors of object usage which we track. We only track the 7173 /// least-sequenced usage of each kind. 7174 enum UsageKind { 7175 /// A read of an object. Multiple unsequenced reads are OK. 7176 UK_Use, 7177 /// A modification of an object which is sequenced before the value 7178 /// computation of the expression, such as ++n in C++. 7179 UK_ModAsValue, 7180 /// A modification of an object which is not sequenced before the value 7181 /// computation of the expression, such as n++. 7182 UK_ModAsSideEffect, 7183 7184 UK_Count = UK_ModAsSideEffect + 1 7185 }; 7186 7187 struct Usage { 7188 Usage() : Use(nullptr), Seq() {} 7189 Expr *Use; 7190 SequenceTree::Seq Seq; 7191 }; 7192 7193 struct UsageInfo { 7194 UsageInfo() : Diagnosed(false) {} 7195 Usage Uses[UK_Count]; 7196 /// Have we issued a diagnostic for this variable already? 7197 bool Diagnosed; 7198 }; 7199 typedef llvm::SmallDenseMap<Object, UsageInfo, 16> UsageInfoMap; 7200 7201 Sema &SemaRef; 7202 /// Sequenced regions within the expression. 7203 SequenceTree Tree; 7204 /// Declaration modifications and references which we have seen. 7205 UsageInfoMap UsageMap; 7206 /// The region we are currently within. 7207 SequenceTree::Seq Region; 7208 /// Filled in with declarations which were modified as a side-effect 7209 /// (that is, post-increment operations). 7210 SmallVectorImpl<std::pair<Object, Usage> > *ModAsSideEffect; 7211 /// Expressions to check later. We defer checking these to reduce 7212 /// stack usage. 7213 SmallVectorImpl<Expr *> &WorkList; 7214 7215 /// RAII object wrapping the visitation of a sequenced subexpression of an 7216 /// expression. At the end of this process, the side-effects of the evaluation 7217 /// become sequenced with respect to the value computation of the result, so 7218 /// we downgrade any UK_ModAsSideEffect within the evaluation to 7219 /// UK_ModAsValue. 7220 struct SequencedSubexpression { 7221 SequencedSubexpression(SequenceChecker &Self) 7222 : Self(Self), OldModAsSideEffect(Self.ModAsSideEffect) { 7223 Self.ModAsSideEffect = &ModAsSideEffect; 7224 } 7225 ~SequencedSubexpression() { 7226 for (auto MI = ModAsSideEffect.rbegin(), ME = ModAsSideEffect.rend(); 7227 MI != ME; ++MI) { 7228 UsageInfo &U = Self.UsageMap[MI->first]; 7229 auto &SideEffectUsage = U.Uses[UK_ModAsSideEffect]; 7230 Self.addUsage(U, MI->first, SideEffectUsage.Use, UK_ModAsValue); 7231 SideEffectUsage = MI->second; 7232 } 7233 Self.ModAsSideEffect = OldModAsSideEffect; 7234 } 7235 7236 SequenceChecker &Self; 7237 SmallVector<std::pair<Object, Usage>, 4> ModAsSideEffect; 7238 SmallVectorImpl<std::pair<Object, Usage> > *OldModAsSideEffect; 7239 }; 7240 7241 /// RAII object wrapping the visitation of a subexpression which we might 7242 /// choose to evaluate as a constant. If any subexpression is evaluated and 7243 /// found to be non-constant, this allows us to suppress the evaluation of 7244 /// the outer expression. 7245 class EvaluationTracker { 7246 public: 7247 EvaluationTracker(SequenceChecker &Self) 7248 : Self(Self), Prev(Self.EvalTracker), EvalOK(true) { 7249 Self.EvalTracker = this; 7250 } 7251 ~EvaluationTracker() { 7252 Self.EvalTracker = Prev; 7253 if (Prev) 7254 Prev->EvalOK &= EvalOK; 7255 } 7256 7257 bool evaluate(const Expr *E, bool &Result) { 7258 if (!EvalOK || E->isValueDependent()) 7259 return false; 7260 EvalOK = E->EvaluateAsBooleanCondition(Result, Self.SemaRef.Context); 7261 return EvalOK; 7262 } 7263 7264 private: 7265 SequenceChecker &Self; 7266 EvaluationTracker *Prev; 7267 bool EvalOK; 7268 } *EvalTracker; 7269 7270 /// \brief Find the object which is produced by the specified expression, 7271 /// if any. 7272 Object getObject(Expr *E, bool Mod) const { 7273 E = E->IgnoreParenCasts(); 7274 if (UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) { 7275 if (Mod && (UO->getOpcode() == UO_PreInc || UO->getOpcode() == UO_PreDec)) 7276 return getObject(UO->getSubExpr(), Mod); 7277 } else if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) { 7278 if (BO->getOpcode() == BO_Comma) 7279 return getObject(BO->getRHS(), Mod); 7280 if (Mod && BO->isAssignmentOp()) 7281 return getObject(BO->getLHS(), Mod); 7282 } else if (MemberExpr *ME = dyn_cast<MemberExpr>(E)) { 7283 // FIXME: Check for more interesting cases, like "x.n = ++x.n". 7284 if (isa<CXXThisExpr>(ME->getBase()->IgnoreParenCasts())) 7285 return ME->getMemberDecl(); 7286 } else if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) 7287 // FIXME: If this is a reference, map through to its value. 7288 return DRE->getDecl(); 7289 return nullptr; 7290 } 7291 7292 /// \brief Note that an object was modified or used by an expression. 7293 void addUsage(UsageInfo &UI, Object O, Expr *Ref, UsageKind UK) { 7294 Usage &U = UI.Uses[UK]; 7295 if (!U.Use || !Tree.isUnsequenced(Region, U.Seq)) { 7296 if (UK == UK_ModAsSideEffect && ModAsSideEffect) 7297 ModAsSideEffect->push_back(std::make_pair(O, U)); 7298 U.Use = Ref; 7299 U.Seq = Region; 7300 } 7301 } 7302 /// \brief Check whether a modification or use conflicts with a prior usage. 7303 void checkUsage(Object O, UsageInfo &UI, Expr *Ref, UsageKind OtherKind, 7304 bool IsModMod) { 7305 if (UI.Diagnosed) 7306 return; 7307 7308 const Usage &U = UI.Uses[OtherKind]; 7309 if (!U.Use || !Tree.isUnsequenced(Region, U.Seq)) 7310 return; 7311 7312 Expr *Mod = U.Use; 7313 Expr *ModOrUse = Ref; 7314 if (OtherKind == UK_Use) 7315 std::swap(Mod, ModOrUse); 7316 7317 SemaRef.Diag(Mod->getExprLoc(), 7318 IsModMod ? diag::warn_unsequenced_mod_mod 7319 : diag::warn_unsequenced_mod_use) 7320 << O << SourceRange(ModOrUse->getExprLoc()); 7321 UI.Diagnosed = true; 7322 } 7323 7324 void notePreUse(Object O, Expr *Use) { 7325 UsageInfo &U = UsageMap[O]; 7326 // Uses conflict with other modifications. 7327 checkUsage(O, U, Use, UK_ModAsValue, false); 7328 } 7329 void notePostUse(Object O, Expr *Use) { 7330 UsageInfo &U = UsageMap[O]; 7331 checkUsage(O, U, Use, UK_ModAsSideEffect, false); 7332 addUsage(U, O, Use, UK_Use); 7333 } 7334 7335 void notePreMod(Object O, Expr *Mod) { 7336 UsageInfo &U = UsageMap[O]; 7337 // Modifications conflict with other modifications and with uses. 7338 checkUsage(O, U, Mod, UK_ModAsValue, true); 7339 checkUsage(O, U, Mod, UK_Use, false); 7340 } 7341 void notePostMod(Object O, Expr *Use, UsageKind UK) { 7342 UsageInfo &U = UsageMap[O]; 7343 checkUsage(O, U, Use, UK_ModAsSideEffect, true); 7344 addUsage(U, O, Use, UK); 7345 } 7346 7347 public: 7348 SequenceChecker(Sema &S, Expr *E, SmallVectorImpl<Expr *> &WorkList) 7349 : Base(S.Context), SemaRef(S), Region(Tree.root()), 7350 ModAsSideEffect(nullptr), WorkList(WorkList), EvalTracker(nullptr) { 7351 Visit(E); 7352 } 7353 7354 void VisitStmt(Stmt *S) { 7355 // Skip all statements which aren't expressions for now. 7356 } 7357 7358 void VisitExpr(Expr *E) { 7359 // By default, just recurse to evaluated subexpressions. 7360 Base::VisitStmt(E); 7361 } 7362 7363 void VisitCastExpr(CastExpr *E) { 7364 Object O = Object(); 7365 if (E->getCastKind() == CK_LValueToRValue) 7366 O = getObject(E->getSubExpr(), false); 7367 7368 if (O) 7369 notePreUse(O, E); 7370 VisitExpr(E); 7371 if (O) 7372 notePostUse(O, E); 7373 } 7374 7375 void VisitBinComma(BinaryOperator *BO) { 7376 // C++11 [expr.comma]p1: 7377 // Every value computation and side effect associated with the left 7378 // expression is sequenced before every value computation and side 7379 // effect associated with the right expression. 7380 SequenceTree::Seq LHS = Tree.allocate(Region); 7381 SequenceTree::Seq RHS = Tree.allocate(Region); 7382 SequenceTree::Seq OldRegion = Region; 7383 7384 { 7385 SequencedSubexpression SeqLHS(*this); 7386 Region = LHS; 7387 Visit(BO->getLHS()); 7388 } 7389 7390 Region = RHS; 7391 Visit(BO->getRHS()); 7392 7393 Region = OldRegion; 7394 7395 // Forget that LHS and RHS are sequenced. They are both unsequenced 7396 // with respect to other stuff. 7397 Tree.merge(LHS); 7398 Tree.merge(RHS); 7399 } 7400 7401 void VisitBinAssign(BinaryOperator *BO) { 7402 // The modification is sequenced after the value computation of the LHS 7403 // and RHS, so check it before inspecting the operands and update the 7404 // map afterwards. 7405 Object O = getObject(BO->getLHS(), true); 7406 if (!O) 7407 return VisitExpr(BO); 7408 7409 notePreMod(O, BO); 7410 7411 // C++11 [expr.ass]p7: 7412 // E1 op= E2 is equivalent to E1 = E1 op E2, except that E1 is evaluated 7413 // only once. 7414 // 7415 // Therefore, for a compound assignment operator, O is considered used 7416 // everywhere except within the evaluation of E1 itself. 7417 if (isa<CompoundAssignOperator>(BO)) 7418 notePreUse(O, BO); 7419 7420 Visit(BO->getLHS()); 7421 7422 if (isa<CompoundAssignOperator>(BO)) 7423 notePostUse(O, BO); 7424 7425 Visit(BO->getRHS()); 7426 7427 // C++11 [expr.ass]p1: 7428 // the assignment is sequenced [...] before the value computation of the 7429 // assignment expression. 7430 // C11 6.5.16/3 has no such rule. 7431 notePostMod(O, BO, SemaRef.getLangOpts().CPlusPlus ? UK_ModAsValue 7432 : UK_ModAsSideEffect); 7433 } 7434 void VisitCompoundAssignOperator(CompoundAssignOperator *CAO) { 7435 VisitBinAssign(CAO); 7436 } 7437 7438 void VisitUnaryPreInc(UnaryOperator *UO) { VisitUnaryPreIncDec(UO); } 7439 void VisitUnaryPreDec(UnaryOperator *UO) { VisitUnaryPreIncDec(UO); } 7440 void VisitUnaryPreIncDec(UnaryOperator *UO) { 7441 Object O = getObject(UO->getSubExpr(), true); 7442 if (!O) 7443 return VisitExpr(UO); 7444 7445 notePreMod(O, UO); 7446 Visit(UO->getSubExpr()); 7447 // C++11 [expr.pre.incr]p1: 7448 // the expression ++x is equivalent to x+=1 7449 notePostMod(O, UO, SemaRef.getLangOpts().CPlusPlus ? UK_ModAsValue 7450 : UK_ModAsSideEffect); 7451 } 7452 7453 void VisitUnaryPostInc(UnaryOperator *UO) { VisitUnaryPostIncDec(UO); } 7454 void VisitUnaryPostDec(UnaryOperator *UO) { VisitUnaryPostIncDec(UO); } 7455 void VisitUnaryPostIncDec(UnaryOperator *UO) { 7456 Object O = getObject(UO->getSubExpr(), true); 7457 if (!O) 7458 return VisitExpr(UO); 7459 7460 notePreMod(O, UO); 7461 Visit(UO->getSubExpr()); 7462 notePostMod(O, UO, UK_ModAsSideEffect); 7463 } 7464 7465 /// Don't visit the RHS of '&&' or '||' if it might not be evaluated. 7466 void VisitBinLOr(BinaryOperator *BO) { 7467 // The side-effects of the LHS of an '&&' are sequenced before the 7468 // value computation of the RHS, and hence before the value computation 7469 // of the '&&' itself, unless the LHS evaluates to zero. We treat them 7470 // as if they were unconditionally sequenced. 7471 EvaluationTracker Eval(*this); 7472 { 7473 SequencedSubexpression Sequenced(*this); 7474 Visit(BO->getLHS()); 7475 } 7476 7477 bool Result; 7478 if (Eval.evaluate(BO->getLHS(), Result)) { 7479 if (!Result) 7480 Visit(BO->getRHS()); 7481 } else { 7482 // Check for unsequenced operations in the RHS, treating it as an 7483 // entirely separate evaluation. 7484 // 7485 // FIXME: If there are operations in the RHS which are unsequenced 7486 // with respect to operations outside the RHS, and those operations 7487 // are unconditionally evaluated, diagnose them. 7488 WorkList.push_back(BO->getRHS()); 7489 } 7490 } 7491 void VisitBinLAnd(BinaryOperator *BO) { 7492 EvaluationTracker Eval(*this); 7493 { 7494 SequencedSubexpression Sequenced(*this); 7495 Visit(BO->getLHS()); 7496 } 7497 7498 bool Result; 7499 if (Eval.evaluate(BO->getLHS(), Result)) { 7500 if (Result) 7501 Visit(BO->getRHS()); 7502 } else { 7503 WorkList.push_back(BO->getRHS()); 7504 } 7505 } 7506 7507 // Only visit the condition, unless we can be sure which subexpression will 7508 // be chosen. 7509 void VisitAbstractConditionalOperator(AbstractConditionalOperator *CO) { 7510 EvaluationTracker Eval(*this); 7511 { 7512 SequencedSubexpression Sequenced(*this); 7513 Visit(CO->getCond()); 7514 } 7515 7516 bool Result; 7517 if (Eval.evaluate(CO->getCond(), Result)) 7518 Visit(Result ? CO->getTrueExpr() : CO->getFalseExpr()); 7519 else { 7520 WorkList.push_back(CO->getTrueExpr()); 7521 WorkList.push_back(CO->getFalseExpr()); 7522 } 7523 } 7524 7525 void VisitCallExpr(CallExpr *CE) { 7526 // C++11 [intro.execution]p15: 7527 // When calling a function [...], every value computation and side effect 7528 // associated with any argument expression, or with the postfix expression 7529 // designating the called function, is sequenced before execution of every 7530 // expression or statement in the body of the function [and thus before 7531 // the value computation of its result]. 7532 SequencedSubexpression Sequenced(*this); 7533 Base::VisitCallExpr(CE); 7534 7535 // FIXME: CXXNewExpr and CXXDeleteExpr implicitly call functions. 7536 } 7537 7538 void VisitCXXConstructExpr(CXXConstructExpr *CCE) { 7539 // This is a call, so all subexpressions are sequenced before the result. 7540 SequencedSubexpression Sequenced(*this); 7541 7542 if (!CCE->isListInitialization()) 7543 return VisitExpr(CCE); 7544 7545 // In C++11, list initializations are sequenced. 7546 SmallVector<SequenceTree::Seq, 32> Elts; 7547 SequenceTree::Seq Parent = Region; 7548 for (CXXConstructExpr::arg_iterator I = CCE->arg_begin(), 7549 E = CCE->arg_end(); 7550 I != E; ++I) { 7551 Region = Tree.allocate(Parent); 7552 Elts.push_back(Region); 7553 Visit(*I); 7554 } 7555 7556 // Forget that the initializers are sequenced. 7557 Region = Parent; 7558 for (unsigned I = 0; I < Elts.size(); ++I) 7559 Tree.merge(Elts[I]); 7560 } 7561 7562 void VisitInitListExpr(InitListExpr *ILE) { 7563 if (!SemaRef.getLangOpts().CPlusPlus11) 7564 return VisitExpr(ILE); 7565 7566 // In C++11, list initializations are sequenced. 7567 SmallVector<SequenceTree::Seq, 32> Elts; 7568 SequenceTree::Seq Parent = Region; 7569 for (unsigned I = 0; I < ILE->getNumInits(); ++I) { 7570 Expr *E = ILE->getInit(I); 7571 if (!E) continue; 7572 Region = Tree.allocate(Parent); 7573 Elts.push_back(Region); 7574 Visit(E); 7575 } 7576 7577 // Forget that the initializers are sequenced. 7578 Region = Parent; 7579 for (unsigned I = 0; I < Elts.size(); ++I) 7580 Tree.merge(Elts[I]); 7581 } 7582 }; 7583 } 7584 7585 void Sema::CheckUnsequencedOperations(Expr *E) { 7586 SmallVector<Expr *, 8> WorkList; 7587 WorkList.push_back(E); 7588 while (!WorkList.empty()) { 7589 Expr *Item = WorkList.pop_back_val(); 7590 SequenceChecker(*this, Item, WorkList); 7591 } 7592 } 7593 7594 void Sema::CheckCompletedExpr(Expr *E, SourceLocation CheckLoc, 7595 bool IsConstexpr) { 7596 CheckImplicitConversions(E, CheckLoc); 7597 CheckUnsequencedOperations(E); 7598 if (!IsConstexpr && !E->isValueDependent()) 7599 CheckForIntOverflow(E); 7600 } 7601 7602 void Sema::CheckBitFieldInitialization(SourceLocation InitLoc, 7603 FieldDecl *BitField, 7604 Expr *Init) { 7605 (void) AnalyzeBitFieldAssignment(*this, BitField, Init, InitLoc); 7606 } 7607 7608 /// CheckParmsForFunctionDef - Check that the parameters of the given 7609 /// function are appropriate for the definition of a function. This 7610 /// takes care of any checks that cannot be performed on the 7611 /// declaration itself, e.g., that the types of each of the function 7612 /// parameters are complete. 7613 bool Sema::CheckParmsForFunctionDef(ParmVarDecl *const *P, 7614 ParmVarDecl *const *PEnd, 7615 bool CheckParameterNames) { 7616 bool HasInvalidParm = false; 7617 for (; P != PEnd; ++P) { 7618 ParmVarDecl *Param = *P; 7619 7620 // C99 6.7.5.3p4: the parameters in a parameter type list in a 7621 // function declarator that is part of a function definition of 7622 // that function shall not have incomplete type. 7623 // 7624 // This is also C++ [dcl.fct]p6. 7625 if (!Param->isInvalidDecl() && 7626 RequireCompleteType(Param->getLocation(), Param->getType(), 7627 diag::err_typecheck_decl_incomplete_type)) { 7628 Param->setInvalidDecl(); 7629 HasInvalidParm = true; 7630 } 7631 7632 // C99 6.9.1p5: If the declarator includes a parameter type list, the 7633 // declaration of each parameter shall include an identifier. 7634 if (CheckParameterNames && 7635 Param->getIdentifier() == nullptr && 7636 !Param->isImplicit() && 7637 !getLangOpts().CPlusPlus) 7638 Diag(Param->getLocation(), diag::err_parameter_name_omitted); 7639 7640 // C99 6.7.5.3p12: 7641 // If the function declarator is not part of a definition of that 7642 // function, parameters may have incomplete type and may use the [*] 7643 // notation in their sequences of declarator specifiers to specify 7644 // variable length array types. 7645 QualType PType = Param->getOriginalType(); 7646 while (const ArrayType *AT = Context.getAsArrayType(PType)) { 7647 if (AT->getSizeModifier() == ArrayType::Star) { 7648 // FIXME: This diagnostic should point the '[*]' if source-location 7649 // information is added for it. 7650 Diag(Param->getLocation(), diag::err_array_star_in_function_definition); 7651 break; 7652 } 7653 PType= AT->getElementType(); 7654 } 7655 7656 // MSVC destroys objects passed by value in the callee. Therefore a 7657 // function definition which takes such a parameter must be able to call the 7658 // object's destructor. However, we don't perform any direct access check 7659 // on the dtor. 7660 if (getLangOpts().CPlusPlus && Context.getTargetInfo() 7661 .getCXXABI() 7662 .areArgsDestroyedLeftToRightInCallee()) { 7663 if (!Param->isInvalidDecl()) { 7664 if (const RecordType *RT = Param->getType()->getAs<RecordType>()) { 7665 CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(RT->getDecl()); 7666 if (!ClassDecl->isInvalidDecl() && 7667 !ClassDecl->hasIrrelevantDestructor() && 7668 !ClassDecl->isDependentContext()) { 7669 CXXDestructorDecl *Destructor = LookupDestructor(ClassDecl); 7670 MarkFunctionReferenced(Param->getLocation(), Destructor); 7671 DiagnoseUseOfDecl(Destructor, Param->getLocation()); 7672 } 7673 } 7674 } 7675 } 7676 } 7677 7678 return HasInvalidParm; 7679 } 7680 7681 /// CheckCastAlign - Implements -Wcast-align, which warns when a 7682 /// pointer cast increases the alignment requirements. 7683 void Sema::CheckCastAlign(Expr *Op, QualType T, SourceRange TRange) { 7684 // This is actually a lot of work to potentially be doing on every 7685 // cast; don't do it if we're ignoring -Wcast_align (as is the default). 7686 if (getDiagnostics().isIgnored(diag::warn_cast_align, TRange.getBegin())) 7687 return; 7688 7689 // Ignore dependent types. 7690 if (T->isDependentType() || Op->getType()->isDependentType()) 7691 return; 7692 7693 // Require that the destination be a pointer type. 7694 const PointerType *DestPtr = T->getAs<PointerType>(); 7695 if (!DestPtr) return; 7696 7697 // If the destination has alignment 1, we're done. 7698 QualType DestPointee = DestPtr->getPointeeType(); 7699 if (DestPointee->isIncompleteType()) return; 7700 CharUnits DestAlign = Context.getTypeAlignInChars(DestPointee); 7701 if (DestAlign.isOne()) return; 7702 7703 // Require that the source be a pointer type. 7704 const PointerType *SrcPtr = Op->getType()->getAs<PointerType>(); 7705 if (!SrcPtr) return; 7706 QualType SrcPointee = SrcPtr->getPointeeType(); 7707 7708 // Whitelist casts from cv void*. We already implicitly 7709 // whitelisted casts to cv void*, since they have alignment 1. 7710 // Also whitelist casts involving incomplete types, which implicitly 7711 // includes 'void'. 7712 if (SrcPointee->isIncompleteType()) return; 7713 7714 CharUnits SrcAlign = Context.getTypeAlignInChars(SrcPointee); 7715 if (SrcAlign >= DestAlign) return; 7716 7717 Diag(TRange.getBegin(), diag::warn_cast_align) 7718 << Op->getType() << T 7719 << static_cast<unsigned>(SrcAlign.getQuantity()) 7720 << static_cast<unsigned>(DestAlign.getQuantity()) 7721 << TRange << Op->getSourceRange(); 7722 } 7723 7724 static const Type* getElementType(const Expr *BaseExpr) { 7725 const Type* EltType = BaseExpr->getType().getTypePtr(); 7726 if (EltType->isAnyPointerType()) 7727 return EltType->getPointeeType().getTypePtr(); 7728 else if (EltType->isArrayType()) 7729 return EltType->getBaseElementTypeUnsafe(); 7730 return EltType; 7731 } 7732 7733 /// \brief Check whether this array fits the idiom of a size-one tail padded 7734 /// array member of a struct. 7735 /// 7736 /// We avoid emitting out-of-bounds access warnings for such arrays as they are 7737 /// commonly used to emulate flexible arrays in C89 code. 7738 static bool IsTailPaddedMemberArray(Sema &S, llvm::APInt Size, 7739 const NamedDecl *ND) { 7740 if (Size != 1 || !ND) return false; 7741 7742 const FieldDecl *FD = dyn_cast<FieldDecl>(ND); 7743 if (!FD) return false; 7744 7745 // Don't consider sizes resulting from macro expansions or template argument 7746 // substitution to form C89 tail-padded arrays. 7747 7748 TypeSourceInfo *TInfo = FD->getTypeSourceInfo(); 7749 while (TInfo) { 7750 TypeLoc TL = TInfo->getTypeLoc(); 7751 // Look through typedefs. 7752 if (TypedefTypeLoc TTL = TL.getAs<TypedefTypeLoc>()) { 7753 const TypedefNameDecl *TDL = TTL.getTypedefNameDecl(); 7754 TInfo = TDL->getTypeSourceInfo(); 7755 continue; 7756 } 7757 if (ConstantArrayTypeLoc CTL = TL.getAs<ConstantArrayTypeLoc>()) { 7758 const Expr *SizeExpr = dyn_cast<IntegerLiteral>(CTL.getSizeExpr()); 7759 if (!SizeExpr || SizeExpr->getExprLoc().isMacroID()) 7760 return false; 7761 } 7762 break; 7763 } 7764 7765 const RecordDecl *RD = dyn_cast<RecordDecl>(FD->getDeclContext()); 7766 if (!RD) return false; 7767 if (RD->isUnion()) return false; 7768 if (const CXXRecordDecl *CRD = dyn_cast<CXXRecordDecl>(RD)) { 7769 if (!CRD->isStandardLayout()) return false; 7770 } 7771 7772 // See if this is the last field decl in the record. 7773 const Decl *D = FD; 7774 while ((D = D->getNextDeclInContext())) 7775 if (isa<FieldDecl>(D)) 7776 return false; 7777 return true; 7778 } 7779 7780 void Sema::CheckArrayAccess(const Expr *BaseExpr, const Expr *IndexExpr, 7781 const ArraySubscriptExpr *ASE, 7782 bool AllowOnePastEnd, bool IndexNegated) { 7783 IndexExpr = IndexExpr->IgnoreParenImpCasts(); 7784 if (IndexExpr->isValueDependent()) 7785 return; 7786 7787 const Type *EffectiveType = getElementType(BaseExpr); 7788 BaseExpr = BaseExpr->IgnoreParenCasts(); 7789 const ConstantArrayType *ArrayTy = 7790 Context.getAsConstantArrayType(BaseExpr->getType()); 7791 if (!ArrayTy) 7792 return; 7793 7794 llvm::APSInt index; 7795 if (!IndexExpr->EvaluateAsInt(index, Context)) 7796 return; 7797 if (IndexNegated) 7798 index = -index; 7799 7800 const NamedDecl *ND = nullptr; 7801 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(BaseExpr)) 7802 ND = dyn_cast<NamedDecl>(DRE->getDecl()); 7803 if (const MemberExpr *ME = dyn_cast<MemberExpr>(BaseExpr)) 7804 ND = dyn_cast<NamedDecl>(ME->getMemberDecl()); 7805 7806 if (index.isUnsigned() || !index.isNegative()) { 7807 llvm::APInt size = ArrayTy->getSize(); 7808 if (!size.isStrictlyPositive()) 7809 return; 7810 7811 const Type* BaseType = getElementType(BaseExpr); 7812 if (BaseType != EffectiveType) { 7813 // Make sure we're comparing apples to apples when comparing index to size 7814 uint64_t ptrarith_typesize = Context.getTypeSize(EffectiveType); 7815 uint64_t array_typesize = Context.getTypeSize(BaseType); 7816 // Handle ptrarith_typesize being zero, such as when casting to void* 7817 if (!ptrarith_typesize) ptrarith_typesize = 1; 7818 if (ptrarith_typesize != array_typesize) { 7819 // There's a cast to a different size type involved 7820 uint64_t ratio = array_typesize / ptrarith_typesize; 7821 // TODO: Be smarter about handling cases where array_typesize is not a 7822 // multiple of ptrarith_typesize 7823 if (ptrarith_typesize * ratio == array_typesize) 7824 size *= llvm::APInt(size.getBitWidth(), ratio); 7825 } 7826 } 7827 7828 if (size.getBitWidth() > index.getBitWidth()) 7829 index = index.zext(size.getBitWidth()); 7830 else if (size.getBitWidth() < index.getBitWidth()) 7831 size = size.zext(index.getBitWidth()); 7832 7833 // For array subscripting the index must be less than size, but for pointer 7834 // arithmetic also allow the index (offset) to be equal to size since 7835 // computing the next address after the end of the array is legal and 7836 // commonly done e.g. in C++ iterators and range-based for loops. 7837 if (AllowOnePastEnd ? index.ule(size) : index.ult(size)) 7838 return; 7839 7840 // Also don't warn for arrays of size 1 which are members of some 7841 // structure. These are often used to approximate flexible arrays in C89 7842 // code. 7843 if (IsTailPaddedMemberArray(*this, size, ND)) 7844 return; 7845 7846 // Suppress the warning if the subscript expression (as identified by the 7847 // ']' location) and the index expression are both from macro expansions 7848 // within a system header. 7849 if (ASE) { 7850 SourceLocation RBracketLoc = SourceMgr.getSpellingLoc( 7851 ASE->getRBracketLoc()); 7852 if (SourceMgr.isInSystemHeader(RBracketLoc)) { 7853 SourceLocation IndexLoc = SourceMgr.getSpellingLoc( 7854 IndexExpr->getLocStart()); 7855 if (SourceMgr.isWrittenInSameFile(RBracketLoc, IndexLoc)) 7856 return; 7857 } 7858 } 7859 7860 unsigned DiagID = diag::warn_ptr_arith_exceeds_bounds; 7861 if (ASE) 7862 DiagID = diag::warn_array_index_exceeds_bounds; 7863 7864 DiagRuntimeBehavior(BaseExpr->getLocStart(), BaseExpr, 7865 PDiag(DiagID) << index.toString(10, true) 7866 << size.toString(10, true) 7867 << (unsigned)size.getLimitedValue(~0U) 7868 << IndexExpr->getSourceRange()); 7869 } else { 7870 unsigned DiagID = diag::warn_array_index_precedes_bounds; 7871 if (!ASE) { 7872 DiagID = diag::warn_ptr_arith_precedes_bounds; 7873 if (index.isNegative()) index = -index; 7874 } 7875 7876 DiagRuntimeBehavior(BaseExpr->getLocStart(), BaseExpr, 7877 PDiag(DiagID) << index.toString(10, true) 7878 << IndexExpr->getSourceRange()); 7879 } 7880 7881 if (!ND) { 7882 // Try harder to find a NamedDecl to point at in the note. 7883 while (const ArraySubscriptExpr *ASE = 7884 dyn_cast<ArraySubscriptExpr>(BaseExpr)) 7885 BaseExpr = ASE->getBase()->IgnoreParenCasts(); 7886 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(BaseExpr)) 7887 ND = dyn_cast<NamedDecl>(DRE->getDecl()); 7888 if (const MemberExpr *ME = dyn_cast<MemberExpr>(BaseExpr)) 7889 ND = dyn_cast<NamedDecl>(ME->getMemberDecl()); 7890 } 7891 7892 if (ND) 7893 DiagRuntimeBehavior(ND->getLocStart(), BaseExpr, 7894 PDiag(diag::note_array_index_out_of_bounds) 7895 << ND->getDeclName()); 7896 } 7897 7898 void Sema::CheckArrayAccess(const Expr *expr) { 7899 int AllowOnePastEnd = 0; 7900 while (expr) { 7901 expr = expr->IgnoreParenImpCasts(); 7902 switch (expr->getStmtClass()) { 7903 case Stmt::ArraySubscriptExprClass: { 7904 const ArraySubscriptExpr *ASE = cast<ArraySubscriptExpr>(expr); 7905 CheckArrayAccess(ASE->getBase(), ASE->getIdx(), ASE, 7906 AllowOnePastEnd > 0); 7907 return; 7908 } 7909 case Stmt::UnaryOperatorClass: { 7910 // Only unwrap the * and & unary operators 7911 const UnaryOperator *UO = cast<UnaryOperator>(expr); 7912 expr = UO->getSubExpr(); 7913 switch (UO->getOpcode()) { 7914 case UO_AddrOf: 7915 AllowOnePastEnd++; 7916 break; 7917 case UO_Deref: 7918 AllowOnePastEnd--; 7919 break; 7920 default: 7921 return; 7922 } 7923 break; 7924 } 7925 case Stmt::ConditionalOperatorClass: { 7926 const ConditionalOperator *cond = cast<ConditionalOperator>(expr); 7927 if (const Expr *lhs = cond->getLHS()) 7928 CheckArrayAccess(lhs); 7929 if (const Expr *rhs = cond->getRHS()) 7930 CheckArrayAccess(rhs); 7931 return; 7932 } 7933 default: 7934 return; 7935 } 7936 } 7937 } 7938 7939 //===--- CHECK: Objective-C retain cycles ----------------------------------// 7940 7941 namespace { 7942 struct RetainCycleOwner { 7943 RetainCycleOwner() : Variable(nullptr), Indirect(false) {} 7944 VarDecl *Variable; 7945 SourceRange Range; 7946 SourceLocation Loc; 7947 bool Indirect; 7948 7949 void setLocsFrom(Expr *e) { 7950 Loc = e->getExprLoc(); 7951 Range = e->getSourceRange(); 7952 } 7953 }; 7954 } 7955 7956 /// Consider whether capturing the given variable can possibly lead to 7957 /// a retain cycle. 7958 static bool considerVariable(VarDecl *var, Expr *ref, RetainCycleOwner &owner) { 7959 // In ARC, it's captured strongly iff the variable has __strong 7960 // lifetime. In MRR, it's captured strongly if the variable is 7961 // __block and has an appropriate type. 7962 if (var->getType().getObjCLifetime() != Qualifiers::OCL_Strong) 7963 return false; 7964 7965 owner.Variable = var; 7966 if (ref) 7967 owner.setLocsFrom(ref); 7968 return true; 7969 } 7970 7971 static bool findRetainCycleOwner(Sema &S, Expr *e, RetainCycleOwner &owner) { 7972 while (true) { 7973 e = e->IgnoreParens(); 7974 if (CastExpr *cast = dyn_cast<CastExpr>(e)) { 7975 switch (cast->getCastKind()) { 7976 case CK_BitCast: 7977 case CK_LValueBitCast: 7978 case CK_LValueToRValue: 7979 case CK_ARCReclaimReturnedObject: 7980 e = cast->getSubExpr(); 7981 continue; 7982 7983 default: 7984 return false; 7985 } 7986 } 7987 7988 if (ObjCIvarRefExpr *ref = dyn_cast<ObjCIvarRefExpr>(e)) { 7989 ObjCIvarDecl *ivar = ref->getDecl(); 7990 if (ivar->getType().getObjCLifetime() != Qualifiers::OCL_Strong) 7991 return false; 7992 7993 // Try to find a retain cycle in the base. 7994 if (!findRetainCycleOwner(S, ref->getBase(), owner)) 7995 return false; 7996 7997 if (ref->isFreeIvar()) owner.setLocsFrom(ref); 7998 owner.Indirect = true; 7999 return true; 8000 } 8001 8002 if (DeclRefExpr *ref = dyn_cast<DeclRefExpr>(e)) { 8003 VarDecl *var = dyn_cast<VarDecl>(ref->getDecl()); 8004 if (!var) return false; 8005 return considerVariable(var, ref, owner); 8006 } 8007 8008 if (MemberExpr *member = dyn_cast<MemberExpr>(e)) { 8009 if (member->isArrow()) return false; 8010 8011 // Don't count this as an indirect ownership. 8012 e = member->getBase(); 8013 continue; 8014 } 8015 8016 if (PseudoObjectExpr *pseudo = dyn_cast<PseudoObjectExpr>(e)) { 8017 // Only pay attention to pseudo-objects on property references. 8018 ObjCPropertyRefExpr *pre 8019 = dyn_cast<ObjCPropertyRefExpr>(pseudo->getSyntacticForm() 8020 ->IgnoreParens()); 8021 if (!pre) return false; 8022 if (pre->isImplicitProperty()) return false; 8023 ObjCPropertyDecl *property = pre->getExplicitProperty(); 8024 if (!property->isRetaining() && 8025 !(property->getPropertyIvarDecl() && 8026 property->getPropertyIvarDecl()->getType() 8027 .getObjCLifetime() == Qualifiers::OCL_Strong)) 8028 return false; 8029 8030 owner.Indirect = true; 8031 if (pre->isSuperReceiver()) { 8032 owner.Variable = S.getCurMethodDecl()->getSelfDecl(); 8033 if (!owner.Variable) 8034 return false; 8035 owner.Loc = pre->getLocation(); 8036 owner.Range = pre->getSourceRange(); 8037 return true; 8038 } 8039 e = const_cast<Expr*>(cast<OpaqueValueExpr>(pre->getBase()) 8040 ->getSourceExpr()); 8041 continue; 8042 } 8043 8044 // Array ivars? 8045 8046 return false; 8047 } 8048 } 8049 8050 namespace { 8051 struct FindCaptureVisitor : EvaluatedExprVisitor<FindCaptureVisitor> { 8052 FindCaptureVisitor(ASTContext &Context, VarDecl *variable) 8053 : EvaluatedExprVisitor<FindCaptureVisitor>(Context), 8054 Context(Context), Variable(variable), Capturer(nullptr), 8055 VarWillBeReased(false) {} 8056 ASTContext &Context; 8057 VarDecl *Variable; 8058 Expr *Capturer; 8059 bool VarWillBeReased; 8060 8061 void VisitDeclRefExpr(DeclRefExpr *ref) { 8062 if (ref->getDecl() == Variable && !Capturer) 8063 Capturer = ref; 8064 } 8065 8066 void VisitObjCIvarRefExpr(ObjCIvarRefExpr *ref) { 8067 if (Capturer) return; 8068 Visit(ref->getBase()); 8069 if (Capturer && ref->isFreeIvar()) 8070 Capturer = ref; 8071 } 8072 8073 void VisitBlockExpr(BlockExpr *block) { 8074 // Look inside nested blocks 8075 if (block->getBlockDecl()->capturesVariable(Variable)) 8076 Visit(block->getBlockDecl()->getBody()); 8077 } 8078 8079 void VisitOpaqueValueExpr(OpaqueValueExpr *OVE) { 8080 if (Capturer) return; 8081 if (OVE->getSourceExpr()) 8082 Visit(OVE->getSourceExpr()); 8083 } 8084 void VisitBinaryOperator(BinaryOperator *BinOp) { 8085 if (!Variable || VarWillBeReased || BinOp->getOpcode() != BO_Assign) 8086 return; 8087 Expr *LHS = BinOp->getLHS(); 8088 if (const DeclRefExpr *DRE = dyn_cast_or_null<DeclRefExpr>(LHS)) { 8089 if (DRE->getDecl() != Variable) 8090 return; 8091 if (Expr *RHS = BinOp->getRHS()) { 8092 RHS = RHS->IgnoreParenCasts(); 8093 llvm::APSInt Value; 8094 VarWillBeReased = 8095 (RHS && RHS->isIntegerConstantExpr(Value, Context) && Value == 0); 8096 } 8097 } 8098 } 8099 }; 8100 } 8101 8102 /// Check whether the given argument is a block which captures a 8103 /// variable. 8104 static Expr *findCapturingExpr(Sema &S, Expr *e, RetainCycleOwner &owner) { 8105 assert(owner.Variable && owner.Loc.isValid()); 8106 8107 e = e->IgnoreParenCasts(); 8108 8109 // Look through [^{...} copy] and Block_copy(^{...}). 8110 if (ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(e)) { 8111 Selector Cmd = ME->getSelector(); 8112 if (Cmd.isUnarySelector() && Cmd.getNameForSlot(0) == "copy") { 8113 e = ME->getInstanceReceiver(); 8114 if (!e) 8115 return nullptr; 8116 e = e->IgnoreParenCasts(); 8117 } 8118 } else if (CallExpr *CE = dyn_cast<CallExpr>(e)) { 8119 if (CE->getNumArgs() == 1) { 8120 FunctionDecl *Fn = dyn_cast_or_null<FunctionDecl>(CE->getCalleeDecl()); 8121 if (Fn) { 8122 const IdentifierInfo *FnI = Fn->getIdentifier(); 8123 if (FnI && FnI->isStr("_Block_copy")) { 8124 e = CE->getArg(0)->IgnoreParenCasts(); 8125 } 8126 } 8127 } 8128 } 8129 8130 BlockExpr *block = dyn_cast<BlockExpr>(e); 8131 if (!block || !block->getBlockDecl()->capturesVariable(owner.Variable)) 8132 return nullptr; 8133 8134 FindCaptureVisitor visitor(S.Context, owner.Variable); 8135 visitor.Visit(block->getBlockDecl()->getBody()); 8136 return visitor.VarWillBeReased ? nullptr : visitor.Capturer; 8137 } 8138 8139 static void diagnoseRetainCycle(Sema &S, Expr *capturer, 8140 RetainCycleOwner &owner) { 8141 assert(capturer); 8142 assert(owner.Variable && owner.Loc.isValid()); 8143 8144 S.Diag(capturer->getExprLoc(), diag::warn_arc_retain_cycle) 8145 << owner.Variable << capturer->getSourceRange(); 8146 S.Diag(owner.Loc, diag::note_arc_retain_cycle_owner) 8147 << owner.Indirect << owner.Range; 8148 } 8149 8150 /// Check for a keyword selector that starts with the word 'add' or 8151 /// 'set'. 8152 static bool isSetterLikeSelector(Selector sel) { 8153 if (sel.isUnarySelector()) return false; 8154 8155 StringRef str = sel.getNameForSlot(0); 8156 while (!str.empty() && str.front() == '_') str = str.substr(1); 8157 if (str.startswith("set")) 8158 str = str.substr(3); 8159 else if (str.startswith("add")) { 8160 // Specially whitelist 'addOperationWithBlock:'. 8161 if (sel.getNumArgs() == 1 && str.startswith("addOperationWithBlock")) 8162 return false; 8163 str = str.substr(3); 8164 } 8165 else 8166 return false; 8167 8168 if (str.empty()) return true; 8169 return !isLowercase(str.front()); 8170 } 8171 8172 /// Check a message send to see if it's likely to cause a retain cycle. 8173 void Sema::checkRetainCycles(ObjCMessageExpr *msg) { 8174 // Only check instance methods whose selector looks like a setter. 8175 if (!msg->isInstanceMessage() || !isSetterLikeSelector(msg->getSelector())) 8176 return; 8177 8178 // Try to find a variable that the receiver is strongly owned by. 8179 RetainCycleOwner owner; 8180 if (msg->getReceiverKind() == ObjCMessageExpr::Instance) { 8181 if (!findRetainCycleOwner(*this, msg->getInstanceReceiver(), owner)) 8182 return; 8183 } else { 8184 assert(msg->getReceiverKind() == ObjCMessageExpr::SuperInstance); 8185 owner.Variable = getCurMethodDecl()->getSelfDecl(); 8186 owner.Loc = msg->getSuperLoc(); 8187 owner.Range = msg->getSuperLoc(); 8188 } 8189 8190 // Check whether the receiver is captured by any of the arguments. 8191 for (unsigned i = 0, e = msg->getNumArgs(); i != e; ++i) 8192 if (Expr *capturer = findCapturingExpr(*this, msg->getArg(i), owner)) 8193 return diagnoseRetainCycle(*this, capturer, owner); 8194 } 8195 8196 /// Check a property assign to see if it's likely to cause a retain cycle. 8197 void Sema::checkRetainCycles(Expr *receiver, Expr *argument) { 8198 RetainCycleOwner owner; 8199 if (!findRetainCycleOwner(*this, receiver, owner)) 8200 return; 8201 8202 if (Expr *capturer = findCapturingExpr(*this, argument, owner)) 8203 diagnoseRetainCycle(*this, capturer, owner); 8204 } 8205 8206 void Sema::checkRetainCycles(VarDecl *Var, Expr *Init) { 8207 RetainCycleOwner Owner; 8208 if (!considerVariable(Var, /*DeclRefExpr=*/nullptr, Owner)) 8209 return; 8210 8211 // Because we don't have an expression for the variable, we have to set the 8212 // location explicitly here. 8213 Owner.Loc = Var->getLocation(); 8214 Owner.Range = Var->getSourceRange(); 8215 8216 if (Expr *Capturer = findCapturingExpr(*this, Init, Owner)) 8217 diagnoseRetainCycle(*this, Capturer, Owner); 8218 } 8219 8220 static bool checkUnsafeAssignLiteral(Sema &S, SourceLocation Loc, 8221 Expr *RHS, bool isProperty) { 8222 // Check if RHS is an Objective-C object literal, which also can get 8223 // immediately zapped in a weak reference. Note that we explicitly 8224 // allow ObjCStringLiterals, since those are designed to never really die. 8225 RHS = RHS->IgnoreParenImpCasts(); 8226 8227 // This enum needs to match with the 'select' in 8228 // warn_objc_arc_literal_assign (off-by-1). 8229 Sema::ObjCLiteralKind Kind = S.CheckLiteralKind(RHS); 8230 if (Kind == Sema::LK_String || Kind == Sema::LK_None) 8231 return false; 8232 8233 S.Diag(Loc, diag::warn_arc_literal_assign) 8234 << (unsigned) Kind 8235 << (isProperty ? 0 : 1) 8236 << RHS->getSourceRange(); 8237 8238 return true; 8239 } 8240 8241 static bool checkUnsafeAssignObject(Sema &S, SourceLocation Loc, 8242 Qualifiers::ObjCLifetime LT, 8243 Expr *RHS, bool isProperty) { 8244 // Strip off any implicit cast added to get to the one ARC-specific. 8245 while (ImplicitCastExpr *cast = dyn_cast<ImplicitCastExpr>(RHS)) { 8246 if (cast->getCastKind() == CK_ARCConsumeObject) { 8247 S.Diag(Loc, diag::warn_arc_retained_assign) 8248 << (LT == Qualifiers::OCL_ExplicitNone) 8249 << (isProperty ? 0 : 1) 8250 << RHS->getSourceRange(); 8251 return true; 8252 } 8253 RHS = cast->getSubExpr(); 8254 } 8255 8256 if (LT == Qualifiers::OCL_Weak && 8257 checkUnsafeAssignLiteral(S, Loc, RHS, isProperty)) 8258 return true; 8259 8260 return false; 8261 } 8262 8263 bool Sema::checkUnsafeAssigns(SourceLocation Loc, 8264 QualType LHS, Expr *RHS) { 8265 Qualifiers::ObjCLifetime LT = LHS.getObjCLifetime(); 8266 8267 if (LT != Qualifiers::OCL_Weak && LT != Qualifiers::OCL_ExplicitNone) 8268 return false; 8269 8270 if (checkUnsafeAssignObject(*this, Loc, LT, RHS, false)) 8271 return true; 8272 8273 return false; 8274 } 8275 8276 void Sema::checkUnsafeExprAssigns(SourceLocation Loc, 8277 Expr *LHS, Expr *RHS) { 8278 QualType LHSType; 8279 // PropertyRef on LHS type need be directly obtained from 8280 // its declaration as it has a PseudoType. 8281 ObjCPropertyRefExpr *PRE 8282 = dyn_cast<ObjCPropertyRefExpr>(LHS->IgnoreParens()); 8283 if (PRE && !PRE->isImplicitProperty()) { 8284 const ObjCPropertyDecl *PD = PRE->getExplicitProperty(); 8285 if (PD) 8286 LHSType = PD->getType(); 8287 } 8288 8289 if (LHSType.isNull()) 8290 LHSType = LHS->getType(); 8291 8292 Qualifiers::ObjCLifetime LT = LHSType.getObjCLifetime(); 8293 8294 if (LT == Qualifiers::OCL_Weak) { 8295 if (!Diags.isIgnored(diag::warn_arc_repeated_use_of_weak, Loc)) 8296 getCurFunction()->markSafeWeakUse(LHS); 8297 } 8298 8299 if (checkUnsafeAssigns(Loc, LHSType, RHS)) 8300 return; 8301 8302 // FIXME. Check for other life times. 8303 if (LT != Qualifiers::OCL_None) 8304 return; 8305 8306 if (PRE) { 8307 if (PRE->isImplicitProperty()) 8308 return; 8309 const ObjCPropertyDecl *PD = PRE->getExplicitProperty(); 8310 if (!PD) 8311 return; 8312 8313 unsigned Attributes = PD->getPropertyAttributes(); 8314 if (Attributes & ObjCPropertyDecl::OBJC_PR_assign) { 8315 // when 'assign' attribute was not explicitly specified 8316 // by user, ignore it and rely on property type itself 8317 // for lifetime info. 8318 unsigned AsWrittenAttr = PD->getPropertyAttributesAsWritten(); 8319 if (!(AsWrittenAttr & ObjCPropertyDecl::OBJC_PR_assign) && 8320 LHSType->isObjCRetainableType()) 8321 return; 8322 8323 while (ImplicitCastExpr *cast = dyn_cast<ImplicitCastExpr>(RHS)) { 8324 if (cast->getCastKind() == CK_ARCConsumeObject) { 8325 Diag(Loc, diag::warn_arc_retained_property_assign) 8326 << RHS->getSourceRange(); 8327 return; 8328 } 8329 RHS = cast->getSubExpr(); 8330 } 8331 } 8332 else if (Attributes & ObjCPropertyDecl::OBJC_PR_weak) { 8333 if (checkUnsafeAssignObject(*this, Loc, Qualifiers::OCL_Weak, RHS, true)) 8334 return; 8335 } 8336 } 8337 } 8338 8339 //===--- CHECK: Empty statement body (-Wempty-body) ---------------------===// 8340 8341 namespace { 8342 bool ShouldDiagnoseEmptyStmtBody(const SourceManager &SourceMgr, 8343 SourceLocation StmtLoc, 8344 const NullStmt *Body) { 8345 // Do not warn if the body is a macro that expands to nothing, e.g: 8346 // 8347 // #define CALL(x) 8348 // if (condition) 8349 // CALL(0); 8350 // 8351 if (Body->hasLeadingEmptyMacro()) 8352 return false; 8353 8354 // Get line numbers of statement and body. 8355 bool StmtLineInvalid; 8356 unsigned StmtLine = SourceMgr.getSpellingLineNumber(StmtLoc, 8357 &StmtLineInvalid); 8358 if (StmtLineInvalid) 8359 return false; 8360 8361 bool BodyLineInvalid; 8362 unsigned BodyLine = SourceMgr.getSpellingLineNumber(Body->getSemiLoc(), 8363 &BodyLineInvalid); 8364 if (BodyLineInvalid) 8365 return false; 8366 8367 // Warn if null statement and body are on the same line. 8368 if (StmtLine != BodyLine) 8369 return false; 8370 8371 return true; 8372 } 8373 } // Unnamed namespace 8374 8375 void Sema::DiagnoseEmptyStmtBody(SourceLocation StmtLoc, 8376 const Stmt *Body, 8377 unsigned DiagID) { 8378 // Since this is a syntactic check, don't emit diagnostic for template 8379 // instantiations, this just adds noise. 8380 if (CurrentInstantiationScope) 8381 return; 8382 8383 // The body should be a null statement. 8384 const NullStmt *NBody = dyn_cast<NullStmt>(Body); 8385 if (!NBody) 8386 return; 8387 8388 // Do the usual checks. 8389 if (!ShouldDiagnoseEmptyStmtBody(SourceMgr, StmtLoc, NBody)) 8390 return; 8391 8392 Diag(NBody->getSemiLoc(), DiagID); 8393 Diag(NBody->getSemiLoc(), diag::note_empty_body_on_separate_line); 8394 } 8395 8396 void Sema::DiagnoseEmptyLoopBody(const Stmt *S, 8397 const Stmt *PossibleBody) { 8398 assert(!CurrentInstantiationScope); // Ensured by caller 8399 8400 SourceLocation StmtLoc; 8401 const Stmt *Body; 8402 unsigned DiagID; 8403 if (const ForStmt *FS = dyn_cast<ForStmt>(S)) { 8404 StmtLoc = FS->getRParenLoc(); 8405 Body = FS->getBody(); 8406 DiagID = diag::warn_empty_for_body; 8407 } else if (const WhileStmt *WS = dyn_cast<WhileStmt>(S)) { 8408 StmtLoc = WS->getCond()->getSourceRange().getEnd(); 8409 Body = WS->getBody(); 8410 DiagID = diag::warn_empty_while_body; 8411 } else 8412 return; // Neither `for' nor `while'. 8413 8414 // The body should be a null statement. 8415 const NullStmt *NBody = dyn_cast<NullStmt>(Body); 8416 if (!NBody) 8417 return; 8418 8419 // Skip expensive checks if diagnostic is disabled. 8420 if (Diags.isIgnored(DiagID, NBody->getSemiLoc())) 8421 return; 8422 8423 // Do the usual checks. 8424 if (!ShouldDiagnoseEmptyStmtBody(SourceMgr, StmtLoc, NBody)) 8425 return; 8426 8427 // `for(...);' and `while(...);' are popular idioms, so in order to keep 8428 // noise level low, emit diagnostics only if for/while is followed by a 8429 // CompoundStmt, e.g.: 8430 // for (int i = 0; i < n; i++); 8431 // { 8432 // a(i); 8433 // } 8434 // or if for/while is followed by a statement with more indentation 8435 // than for/while itself: 8436 // for (int i = 0; i < n; i++); 8437 // a(i); 8438 bool ProbableTypo = isa<CompoundStmt>(PossibleBody); 8439 if (!ProbableTypo) { 8440 bool BodyColInvalid; 8441 unsigned BodyCol = SourceMgr.getPresumedColumnNumber( 8442 PossibleBody->getLocStart(), 8443 &BodyColInvalid); 8444 if (BodyColInvalid) 8445 return; 8446 8447 bool StmtColInvalid; 8448 unsigned StmtCol = SourceMgr.getPresumedColumnNumber( 8449 S->getLocStart(), 8450 &StmtColInvalid); 8451 if (StmtColInvalid) 8452 return; 8453 8454 if (BodyCol > StmtCol) 8455 ProbableTypo = true; 8456 } 8457 8458 if (ProbableTypo) { 8459 Diag(NBody->getSemiLoc(), DiagID); 8460 Diag(NBody->getSemiLoc(), diag::note_empty_body_on_separate_line); 8461 } 8462 } 8463 8464 //===--- CHECK: Warn on self move with std::move. -------------------------===// 8465 8466 /// DiagnoseSelfMove - Emits a warning if a value is moved to itself. 8467 void Sema::DiagnoseSelfMove(const Expr *LHSExpr, const Expr *RHSExpr, 8468 SourceLocation OpLoc) { 8469 8470 if (Diags.isIgnored(diag::warn_sizeof_pointer_expr_memaccess, OpLoc)) 8471 return; 8472 8473 if (!ActiveTemplateInstantiations.empty()) 8474 return; 8475 8476 // Strip parens and casts away. 8477 LHSExpr = LHSExpr->IgnoreParenImpCasts(); 8478 RHSExpr = RHSExpr->IgnoreParenImpCasts(); 8479 8480 // Check for a call expression 8481 const CallExpr *CE = dyn_cast<CallExpr>(RHSExpr); 8482 if (!CE || CE->getNumArgs() != 1) 8483 return; 8484 8485 // Check for a call to std::move 8486 const FunctionDecl *FD = CE->getDirectCallee(); 8487 if (!FD || !FD->isInStdNamespace() || !FD->getIdentifier() || 8488 !FD->getIdentifier()->isStr("move")) 8489 return; 8490 8491 // Get argument from std::move 8492 RHSExpr = CE->getArg(0); 8493 8494 const DeclRefExpr *LHSDeclRef = dyn_cast<DeclRefExpr>(LHSExpr); 8495 const DeclRefExpr *RHSDeclRef = dyn_cast<DeclRefExpr>(RHSExpr); 8496 8497 // Two DeclRefExpr's, check that the decls are the same. 8498 if (LHSDeclRef && RHSDeclRef) { 8499 if (!LHSDeclRef->getDecl() || !RHSDeclRef->getDecl()) 8500 return; 8501 if (LHSDeclRef->getDecl()->getCanonicalDecl() != 8502 RHSDeclRef->getDecl()->getCanonicalDecl()) 8503 return; 8504 8505 Diag(OpLoc, diag::warn_self_move) << LHSExpr->getType() 8506 << LHSExpr->getSourceRange() 8507 << RHSExpr->getSourceRange(); 8508 return; 8509 } 8510 8511 // Member variables require a different approach to check for self moves. 8512 // MemberExpr's are the same if every nested MemberExpr refers to the same 8513 // Decl and that the base Expr's are DeclRefExpr's with the same Decl or 8514 // the base Expr's are CXXThisExpr's. 8515 const Expr *LHSBase = LHSExpr; 8516 const Expr *RHSBase = RHSExpr; 8517 const MemberExpr *LHSME = dyn_cast<MemberExpr>(LHSExpr); 8518 const MemberExpr *RHSME = dyn_cast<MemberExpr>(RHSExpr); 8519 if (!LHSME || !RHSME) 8520 return; 8521 8522 while (LHSME && RHSME) { 8523 if (LHSME->getMemberDecl()->getCanonicalDecl() != 8524 RHSME->getMemberDecl()->getCanonicalDecl()) 8525 return; 8526 8527 LHSBase = LHSME->getBase(); 8528 RHSBase = RHSME->getBase(); 8529 LHSME = dyn_cast<MemberExpr>(LHSBase); 8530 RHSME = dyn_cast<MemberExpr>(RHSBase); 8531 } 8532 8533 LHSDeclRef = dyn_cast<DeclRefExpr>(LHSBase); 8534 RHSDeclRef = dyn_cast<DeclRefExpr>(RHSBase); 8535 if (LHSDeclRef && RHSDeclRef) { 8536 if (!LHSDeclRef->getDecl() || !RHSDeclRef->getDecl()) 8537 return; 8538 if (LHSDeclRef->getDecl()->getCanonicalDecl() != 8539 RHSDeclRef->getDecl()->getCanonicalDecl()) 8540 return; 8541 8542 Diag(OpLoc, diag::warn_self_move) << LHSExpr->getType() 8543 << LHSExpr->getSourceRange() 8544 << RHSExpr->getSourceRange(); 8545 return; 8546 } 8547 8548 if (isa<CXXThisExpr>(LHSBase) && isa<CXXThisExpr>(RHSBase)) 8549 Diag(OpLoc, diag::warn_self_move) << LHSExpr->getType() 8550 << LHSExpr->getSourceRange() 8551 << RHSExpr->getSourceRange(); 8552 } 8553 8554 //===--- Layout compatibility ----------------------------------------------// 8555 8556 namespace { 8557 8558 bool isLayoutCompatible(ASTContext &C, QualType T1, QualType T2); 8559 8560 /// \brief Check if two enumeration types are layout-compatible. 8561 bool isLayoutCompatible(ASTContext &C, EnumDecl *ED1, EnumDecl *ED2) { 8562 // C++11 [dcl.enum] p8: 8563 // Two enumeration types are layout-compatible if they have the same 8564 // underlying type. 8565 return ED1->isComplete() && ED2->isComplete() && 8566 C.hasSameType(ED1->getIntegerType(), ED2->getIntegerType()); 8567 } 8568 8569 /// \brief Check if two fields are layout-compatible. 8570 bool isLayoutCompatible(ASTContext &C, FieldDecl *Field1, FieldDecl *Field2) { 8571 if (!isLayoutCompatible(C, Field1->getType(), Field2->getType())) 8572 return false; 8573 8574 if (Field1->isBitField() != Field2->isBitField()) 8575 return false; 8576 8577 if (Field1->isBitField()) { 8578 // Make sure that the bit-fields are the same length. 8579 unsigned Bits1 = Field1->getBitWidthValue(C); 8580 unsigned Bits2 = Field2->getBitWidthValue(C); 8581 8582 if (Bits1 != Bits2) 8583 return false; 8584 } 8585 8586 return true; 8587 } 8588 8589 /// \brief Check if two standard-layout structs are layout-compatible. 8590 /// (C++11 [class.mem] p17) 8591 bool isLayoutCompatibleStruct(ASTContext &C, 8592 RecordDecl *RD1, 8593 RecordDecl *RD2) { 8594 // If both records are C++ classes, check that base classes match. 8595 if (const CXXRecordDecl *D1CXX = dyn_cast<CXXRecordDecl>(RD1)) { 8596 // If one of records is a CXXRecordDecl we are in C++ mode, 8597 // thus the other one is a CXXRecordDecl, too. 8598 const CXXRecordDecl *D2CXX = cast<CXXRecordDecl>(RD2); 8599 // Check number of base classes. 8600 if (D1CXX->getNumBases() != D2CXX->getNumBases()) 8601 return false; 8602 8603 // Check the base classes. 8604 for (CXXRecordDecl::base_class_const_iterator 8605 Base1 = D1CXX->bases_begin(), 8606 BaseEnd1 = D1CXX->bases_end(), 8607 Base2 = D2CXX->bases_begin(); 8608 Base1 != BaseEnd1; 8609 ++Base1, ++Base2) { 8610 if (!isLayoutCompatible(C, Base1->getType(), Base2->getType())) 8611 return false; 8612 } 8613 } else if (const CXXRecordDecl *D2CXX = dyn_cast<CXXRecordDecl>(RD2)) { 8614 // If only RD2 is a C++ class, it should have zero base classes. 8615 if (D2CXX->getNumBases() > 0) 8616 return false; 8617 } 8618 8619 // Check the fields. 8620 RecordDecl::field_iterator Field2 = RD2->field_begin(), 8621 Field2End = RD2->field_end(), 8622 Field1 = RD1->field_begin(), 8623 Field1End = RD1->field_end(); 8624 for ( ; Field1 != Field1End && Field2 != Field2End; ++Field1, ++Field2) { 8625 if (!isLayoutCompatible(C, *Field1, *Field2)) 8626 return false; 8627 } 8628 if (Field1 != Field1End || Field2 != Field2End) 8629 return false; 8630 8631 return true; 8632 } 8633 8634 /// \brief Check if two standard-layout unions are layout-compatible. 8635 /// (C++11 [class.mem] p18) 8636 bool isLayoutCompatibleUnion(ASTContext &C, 8637 RecordDecl *RD1, 8638 RecordDecl *RD2) { 8639 llvm::SmallPtrSet<FieldDecl *, 8> UnmatchedFields; 8640 for (auto *Field2 : RD2->fields()) 8641 UnmatchedFields.insert(Field2); 8642 8643 for (auto *Field1 : RD1->fields()) { 8644 llvm::SmallPtrSet<FieldDecl *, 8>::iterator 8645 I = UnmatchedFields.begin(), 8646 E = UnmatchedFields.end(); 8647 8648 for ( ; I != E; ++I) { 8649 if (isLayoutCompatible(C, Field1, *I)) { 8650 bool Result = UnmatchedFields.erase(*I); 8651 (void) Result; 8652 assert(Result); 8653 break; 8654 } 8655 } 8656 if (I == E) 8657 return false; 8658 } 8659 8660 return UnmatchedFields.empty(); 8661 } 8662 8663 bool isLayoutCompatible(ASTContext &C, RecordDecl *RD1, RecordDecl *RD2) { 8664 if (RD1->isUnion() != RD2->isUnion()) 8665 return false; 8666 8667 if (RD1->isUnion()) 8668 return isLayoutCompatibleUnion(C, RD1, RD2); 8669 else 8670 return isLayoutCompatibleStruct(C, RD1, RD2); 8671 } 8672 8673 /// \brief Check if two types are layout-compatible in C++11 sense. 8674 bool isLayoutCompatible(ASTContext &C, QualType T1, QualType T2) { 8675 if (T1.isNull() || T2.isNull()) 8676 return false; 8677 8678 // C++11 [basic.types] p11: 8679 // If two types T1 and T2 are the same type, then T1 and T2 are 8680 // layout-compatible types. 8681 if (C.hasSameType(T1, T2)) 8682 return true; 8683 8684 T1 = T1.getCanonicalType().getUnqualifiedType(); 8685 T2 = T2.getCanonicalType().getUnqualifiedType(); 8686 8687 const Type::TypeClass TC1 = T1->getTypeClass(); 8688 const Type::TypeClass TC2 = T2->getTypeClass(); 8689 8690 if (TC1 != TC2) 8691 return false; 8692 8693 if (TC1 == Type::Enum) { 8694 return isLayoutCompatible(C, 8695 cast<EnumType>(T1)->getDecl(), 8696 cast<EnumType>(T2)->getDecl()); 8697 } else if (TC1 == Type::Record) { 8698 if (!T1->isStandardLayoutType() || !T2->isStandardLayoutType()) 8699 return false; 8700 8701 return isLayoutCompatible(C, 8702 cast<RecordType>(T1)->getDecl(), 8703 cast<RecordType>(T2)->getDecl()); 8704 } 8705 8706 return false; 8707 } 8708 } 8709 8710 //===--- CHECK: pointer_with_type_tag attribute: datatypes should match ----// 8711 8712 namespace { 8713 /// \brief Given a type tag expression find the type tag itself. 8714 /// 8715 /// \param TypeExpr Type tag expression, as it appears in user's code. 8716 /// 8717 /// \param VD Declaration of an identifier that appears in a type tag. 8718 /// 8719 /// \param MagicValue Type tag magic value. 8720 bool FindTypeTagExpr(const Expr *TypeExpr, const ASTContext &Ctx, 8721 const ValueDecl **VD, uint64_t *MagicValue) { 8722 while(true) { 8723 if (!TypeExpr) 8724 return false; 8725 8726 TypeExpr = TypeExpr->IgnoreParenImpCasts()->IgnoreParenCasts(); 8727 8728 switch (TypeExpr->getStmtClass()) { 8729 case Stmt::UnaryOperatorClass: { 8730 const UnaryOperator *UO = cast<UnaryOperator>(TypeExpr); 8731 if (UO->getOpcode() == UO_AddrOf || UO->getOpcode() == UO_Deref) { 8732 TypeExpr = UO->getSubExpr(); 8733 continue; 8734 } 8735 return false; 8736 } 8737 8738 case Stmt::DeclRefExprClass: { 8739 const DeclRefExpr *DRE = cast<DeclRefExpr>(TypeExpr); 8740 *VD = DRE->getDecl(); 8741 return true; 8742 } 8743 8744 case Stmt::IntegerLiteralClass: { 8745 const IntegerLiteral *IL = cast<IntegerLiteral>(TypeExpr); 8746 llvm::APInt MagicValueAPInt = IL->getValue(); 8747 if (MagicValueAPInt.getActiveBits() <= 64) { 8748 *MagicValue = MagicValueAPInt.getZExtValue(); 8749 return true; 8750 } else 8751 return false; 8752 } 8753 8754 case Stmt::BinaryConditionalOperatorClass: 8755 case Stmt::ConditionalOperatorClass: { 8756 const AbstractConditionalOperator *ACO = 8757 cast<AbstractConditionalOperator>(TypeExpr); 8758 bool Result; 8759 if (ACO->getCond()->EvaluateAsBooleanCondition(Result, Ctx)) { 8760 if (Result) 8761 TypeExpr = ACO->getTrueExpr(); 8762 else 8763 TypeExpr = ACO->getFalseExpr(); 8764 continue; 8765 } 8766 return false; 8767 } 8768 8769 case Stmt::BinaryOperatorClass: { 8770 const BinaryOperator *BO = cast<BinaryOperator>(TypeExpr); 8771 if (BO->getOpcode() == BO_Comma) { 8772 TypeExpr = BO->getRHS(); 8773 continue; 8774 } 8775 return false; 8776 } 8777 8778 default: 8779 return false; 8780 } 8781 } 8782 } 8783 8784 /// \brief Retrieve the C type corresponding to type tag TypeExpr. 8785 /// 8786 /// \param TypeExpr Expression that specifies a type tag. 8787 /// 8788 /// \param MagicValues Registered magic values. 8789 /// 8790 /// \param FoundWrongKind Set to true if a type tag was found, but of a wrong 8791 /// kind. 8792 /// 8793 /// \param TypeInfo Information about the corresponding C type. 8794 /// 8795 /// \returns true if the corresponding C type was found. 8796 bool GetMatchingCType( 8797 const IdentifierInfo *ArgumentKind, 8798 const Expr *TypeExpr, const ASTContext &Ctx, 8799 const llvm::DenseMap<Sema::TypeTagMagicValue, 8800 Sema::TypeTagData> *MagicValues, 8801 bool &FoundWrongKind, 8802 Sema::TypeTagData &TypeInfo) { 8803 FoundWrongKind = false; 8804 8805 // Variable declaration that has type_tag_for_datatype attribute. 8806 const ValueDecl *VD = nullptr; 8807 8808 uint64_t MagicValue; 8809 8810 if (!FindTypeTagExpr(TypeExpr, Ctx, &VD, &MagicValue)) 8811 return false; 8812 8813 if (VD) { 8814 if (TypeTagForDatatypeAttr *I = VD->getAttr<TypeTagForDatatypeAttr>()) { 8815 if (I->getArgumentKind() != ArgumentKind) { 8816 FoundWrongKind = true; 8817 return false; 8818 } 8819 TypeInfo.Type = I->getMatchingCType(); 8820 TypeInfo.LayoutCompatible = I->getLayoutCompatible(); 8821 TypeInfo.MustBeNull = I->getMustBeNull(); 8822 return true; 8823 } 8824 return false; 8825 } 8826 8827 if (!MagicValues) 8828 return false; 8829 8830 llvm::DenseMap<Sema::TypeTagMagicValue, 8831 Sema::TypeTagData>::const_iterator I = 8832 MagicValues->find(std::make_pair(ArgumentKind, MagicValue)); 8833 if (I == MagicValues->end()) 8834 return false; 8835 8836 TypeInfo = I->second; 8837 return true; 8838 } 8839 } // unnamed namespace 8840 8841 void Sema::RegisterTypeTagForDatatype(const IdentifierInfo *ArgumentKind, 8842 uint64_t MagicValue, QualType Type, 8843 bool LayoutCompatible, 8844 bool MustBeNull) { 8845 if (!TypeTagForDatatypeMagicValues) 8846 TypeTagForDatatypeMagicValues.reset( 8847 new llvm::DenseMap<TypeTagMagicValue, TypeTagData>); 8848 8849 TypeTagMagicValue Magic(ArgumentKind, MagicValue); 8850 (*TypeTagForDatatypeMagicValues)[Magic] = 8851 TypeTagData(Type, LayoutCompatible, MustBeNull); 8852 } 8853 8854 namespace { 8855 bool IsSameCharType(QualType T1, QualType T2) { 8856 const BuiltinType *BT1 = T1->getAs<BuiltinType>(); 8857 if (!BT1) 8858 return false; 8859 8860 const BuiltinType *BT2 = T2->getAs<BuiltinType>(); 8861 if (!BT2) 8862 return false; 8863 8864 BuiltinType::Kind T1Kind = BT1->getKind(); 8865 BuiltinType::Kind T2Kind = BT2->getKind(); 8866 8867 return (T1Kind == BuiltinType::SChar && T2Kind == BuiltinType::Char_S) || 8868 (T1Kind == BuiltinType::UChar && T2Kind == BuiltinType::Char_U) || 8869 (T1Kind == BuiltinType::Char_U && T2Kind == BuiltinType::UChar) || 8870 (T1Kind == BuiltinType::Char_S && T2Kind == BuiltinType::SChar); 8871 } 8872 } // unnamed namespace 8873 8874 void Sema::CheckArgumentWithTypeTag(const ArgumentWithTypeTagAttr *Attr, 8875 const Expr * const *ExprArgs) { 8876 const IdentifierInfo *ArgumentKind = Attr->getArgumentKind(); 8877 bool IsPointerAttr = Attr->getIsPointer(); 8878 8879 const Expr *TypeTagExpr = ExprArgs[Attr->getTypeTagIdx()]; 8880 bool FoundWrongKind; 8881 TypeTagData TypeInfo; 8882 if (!GetMatchingCType(ArgumentKind, TypeTagExpr, Context, 8883 TypeTagForDatatypeMagicValues.get(), 8884 FoundWrongKind, TypeInfo)) { 8885 if (FoundWrongKind) 8886 Diag(TypeTagExpr->getExprLoc(), 8887 diag::warn_type_tag_for_datatype_wrong_kind) 8888 << TypeTagExpr->getSourceRange(); 8889 return; 8890 } 8891 8892 const Expr *ArgumentExpr = ExprArgs[Attr->getArgumentIdx()]; 8893 if (IsPointerAttr) { 8894 // Skip implicit cast of pointer to `void *' (as a function argument). 8895 if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(ArgumentExpr)) 8896 if (ICE->getType()->isVoidPointerType() && 8897 ICE->getCastKind() == CK_BitCast) 8898 ArgumentExpr = ICE->getSubExpr(); 8899 } 8900 QualType ArgumentType = ArgumentExpr->getType(); 8901 8902 // Passing a `void*' pointer shouldn't trigger a warning. 8903 if (IsPointerAttr && ArgumentType->isVoidPointerType()) 8904 return; 8905 8906 if (TypeInfo.MustBeNull) { 8907 // Type tag with matching void type requires a null pointer. 8908 if (!ArgumentExpr->isNullPointerConstant(Context, 8909 Expr::NPC_ValueDependentIsNotNull)) { 8910 Diag(ArgumentExpr->getExprLoc(), 8911 diag::warn_type_safety_null_pointer_required) 8912 << ArgumentKind->getName() 8913 << ArgumentExpr->getSourceRange() 8914 << TypeTagExpr->getSourceRange(); 8915 } 8916 return; 8917 } 8918 8919 QualType RequiredType = TypeInfo.Type; 8920 if (IsPointerAttr) 8921 RequiredType = Context.getPointerType(RequiredType); 8922 8923 bool mismatch = false; 8924 if (!TypeInfo.LayoutCompatible) { 8925 mismatch = !Context.hasSameType(ArgumentType, RequiredType); 8926 8927 // C++11 [basic.fundamental] p1: 8928 // Plain char, signed char, and unsigned char are three distinct types. 8929 // 8930 // But we treat plain `char' as equivalent to `signed char' or `unsigned 8931 // char' depending on the current char signedness mode. 8932 if (mismatch) 8933 if ((IsPointerAttr && IsSameCharType(ArgumentType->getPointeeType(), 8934 RequiredType->getPointeeType())) || 8935 (!IsPointerAttr && IsSameCharType(ArgumentType, RequiredType))) 8936 mismatch = false; 8937 } else 8938 if (IsPointerAttr) 8939 mismatch = !isLayoutCompatible(Context, 8940 ArgumentType->getPointeeType(), 8941 RequiredType->getPointeeType()); 8942 else 8943 mismatch = !isLayoutCompatible(Context, ArgumentType, RequiredType); 8944 8945 if (mismatch) 8946 Diag(ArgumentExpr->getExprLoc(), diag::warn_type_safety_type_mismatch) 8947 << ArgumentType << ArgumentKind 8948 << TypeInfo.LayoutCompatible << RequiredType 8949 << ArgumentExpr->getSourceRange() 8950 << TypeTagExpr->getSourceRange(); 8951 } 8952 8953