1 //===--- SemaChecking.cpp - Extra Semantic Checking -----------------------===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // This file implements extra semantic analysis beyond what is enforced 11 // by the C type system. 12 // 13 //===----------------------------------------------------------------------===// 14 15 #include "clang/Sema/SemaInternal.h" 16 #include "clang/AST/ASTContext.h" 17 #include "clang/AST/CharUnits.h" 18 #include "clang/AST/DeclCXX.h" 19 #include "clang/AST/DeclObjC.h" 20 #include "clang/AST/EvaluatedExprVisitor.h" 21 #include "clang/AST/Expr.h" 22 #include "clang/AST/ExprCXX.h" 23 #include "clang/AST/ExprObjC.h" 24 #include "clang/AST/StmtCXX.h" 25 #include "clang/AST/StmtObjC.h" 26 #include "clang/Analysis/Analyses/FormatString.h" 27 #include "clang/Basic/CharInfo.h" 28 #include "clang/Basic/TargetBuiltins.h" 29 #include "clang/Basic/TargetInfo.h" 30 #include "clang/Lex/Lexer.h" // TODO: Extract static functions to fix layering. 31 #include "clang/Sema/Initialization.h" 32 #include "clang/Sema/Lookup.h" 33 #include "clang/Sema/ScopeInfo.h" 34 #include "clang/Sema/Sema.h" 35 #include "llvm/ADT/STLExtras.h" 36 #include "llvm/ADT/SmallBitVector.h" 37 #include "llvm/ADT/SmallString.h" 38 #include "llvm/Support/ConvertUTF.h" 39 #include "llvm/Support/raw_ostream.h" 40 #include <limits> 41 using namespace clang; 42 using namespace sema; 43 44 SourceLocation Sema::getLocationOfStringLiteralByte(const StringLiteral *SL, 45 unsigned ByteNo) const { 46 return SL->getLocationOfByte(ByteNo, getSourceManager(), LangOpts, 47 Context.getTargetInfo()); 48 } 49 50 /// Checks that a call expression's argument count is the desired number. 51 /// This is useful when doing custom type-checking. Returns true on error. 52 static bool checkArgCount(Sema &S, CallExpr *call, unsigned desiredArgCount) { 53 unsigned argCount = call->getNumArgs(); 54 if (argCount == desiredArgCount) return false; 55 56 if (argCount < desiredArgCount) 57 return S.Diag(call->getLocEnd(), diag::err_typecheck_call_too_few_args) 58 << 0 /*function call*/ << desiredArgCount << argCount 59 << call->getSourceRange(); 60 61 // Highlight all the excess arguments. 62 SourceRange range(call->getArg(desiredArgCount)->getLocStart(), 63 call->getArg(argCount - 1)->getLocEnd()); 64 65 return S.Diag(range.getBegin(), diag::err_typecheck_call_too_many_args) 66 << 0 /*function call*/ << desiredArgCount << argCount 67 << call->getArg(1)->getSourceRange(); 68 } 69 70 /// Check that the first argument to __builtin_annotation is an integer 71 /// and the second argument is a non-wide string literal. 72 static bool SemaBuiltinAnnotation(Sema &S, CallExpr *TheCall) { 73 if (checkArgCount(S, TheCall, 2)) 74 return true; 75 76 // First argument should be an integer. 77 Expr *ValArg = TheCall->getArg(0); 78 QualType Ty = ValArg->getType(); 79 if (!Ty->isIntegerType()) { 80 S.Diag(ValArg->getLocStart(), diag::err_builtin_annotation_first_arg) 81 << ValArg->getSourceRange(); 82 return true; 83 } 84 85 // Second argument should be a constant string. 86 Expr *StrArg = TheCall->getArg(1)->IgnoreParenCasts(); 87 StringLiteral *Literal = dyn_cast<StringLiteral>(StrArg); 88 if (!Literal || !Literal->isAscii()) { 89 S.Diag(StrArg->getLocStart(), diag::err_builtin_annotation_second_arg) 90 << StrArg->getSourceRange(); 91 return true; 92 } 93 94 TheCall->setType(Ty); 95 return false; 96 } 97 98 /// Check that the argument to __builtin_addressof is a glvalue, and set the 99 /// result type to the corresponding pointer type. 100 static bool SemaBuiltinAddressof(Sema &S, CallExpr *TheCall) { 101 if (checkArgCount(S, TheCall, 1)) 102 return true; 103 104 ExprResult Arg(TheCall->getArg(0)); 105 QualType ResultType = S.CheckAddressOfOperand(Arg, TheCall->getLocStart()); 106 if (ResultType.isNull()) 107 return true; 108 109 TheCall->setArg(0, Arg.get()); 110 TheCall->setType(ResultType); 111 return false; 112 } 113 114 static void SemaBuiltinMemChkCall(Sema &S, FunctionDecl *FDecl, 115 CallExpr *TheCall, unsigned SizeIdx, 116 unsigned DstSizeIdx) { 117 if (TheCall->getNumArgs() <= SizeIdx || 118 TheCall->getNumArgs() <= DstSizeIdx) 119 return; 120 121 const Expr *SizeArg = TheCall->getArg(SizeIdx); 122 const Expr *DstSizeArg = TheCall->getArg(DstSizeIdx); 123 124 llvm::APSInt Size, DstSize; 125 126 // find out if both sizes are known at compile time 127 if (!SizeArg->EvaluateAsInt(Size, S.Context) || 128 !DstSizeArg->EvaluateAsInt(DstSize, S.Context)) 129 return; 130 131 if (Size.ule(DstSize)) 132 return; 133 134 // confirmed overflow so generate the diagnostic. 135 IdentifierInfo *FnName = FDecl->getIdentifier(); 136 SourceLocation SL = TheCall->getLocStart(); 137 SourceRange SR = TheCall->getSourceRange(); 138 139 S.Diag(SL, diag::warn_memcpy_chk_overflow) << SR << FnName; 140 } 141 142 static bool SemaBuiltinCallWithStaticChain(Sema &S, CallExpr *BuiltinCall) { 143 if (checkArgCount(S, BuiltinCall, 2)) 144 return true; 145 146 SourceLocation BuiltinLoc = BuiltinCall->getLocStart(); 147 Expr *Builtin = BuiltinCall->getCallee()->IgnoreImpCasts(); 148 Expr *Call = BuiltinCall->getArg(0); 149 Expr *Chain = BuiltinCall->getArg(1); 150 151 if (Call->getStmtClass() != Stmt::CallExprClass) { 152 S.Diag(BuiltinLoc, diag::err_first_argument_to_cwsc_not_call) 153 << Call->getSourceRange(); 154 return true; 155 } 156 157 auto CE = cast<CallExpr>(Call); 158 if (CE->getCallee()->getType()->isBlockPointerType()) { 159 S.Diag(BuiltinLoc, diag::err_first_argument_to_cwsc_block_call) 160 << Call->getSourceRange(); 161 return true; 162 } 163 164 const Decl *TargetDecl = CE->getCalleeDecl(); 165 if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(TargetDecl)) 166 if (FD->getBuiltinID()) { 167 S.Diag(BuiltinLoc, diag::err_first_argument_to_cwsc_builtin_call) 168 << Call->getSourceRange(); 169 return true; 170 } 171 172 if (isa<CXXPseudoDestructorExpr>(CE->getCallee()->IgnoreParens())) { 173 S.Diag(BuiltinLoc, diag::err_first_argument_to_cwsc_pdtor_call) 174 << Call->getSourceRange(); 175 return true; 176 } 177 178 ExprResult ChainResult = S.UsualUnaryConversions(Chain); 179 if (ChainResult.isInvalid()) 180 return true; 181 if (!ChainResult.get()->getType()->isPointerType()) { 182 S.Diag(BuiltinLoc, diag::err_second_argument_to_cwsc_not_pointer) 183 << Chain->getSourceRange(); 184 return true; 185 } 186 187 QualType ReturnTy = CE->getCallReturnType(); 188 QualType ArgTys[2] = { ReturnTy, ChainResult.get()->getType() }; 189 QualType BuiltinTy = S.Context.getFunctionType( 190 ReturnTy, ArgTys, FunctionProtoType::ExtProtoInfo()); 191 QualType BuiltinPtrTy = S.Context.getPointerType(BuiltinTy); 192 193 Builtin = 194 S.ImpCastExprToType(Builtin, BuiltinPtrTy, CK_BuiltinFnToFnPtr).get(); 195 196 BuiltinCall->setType(CE->getType()); 197 BuiltinCall->setValueKind(CE->getValueKind()); 198 BuiltinCall->setObjectKind(CE->getObjectKind()); 199 BuiltinCall->setCallee(Builtin); 200 BuiltinCall->setArg(1, ChainResult.get()); 201 202 return false; 203 } 204 205 static bool SemaBuiltinSEHScopeCheck(Sema &SemaRef, CallExpr *TheCall, 206 Scope::ScopeFlags NeededScopeFlags, 207 unsigned DiagID) { 208 // Scopes aren't available during instantiation. Fortunately, builtin 209 // functions cannot be template args so they cannot be formed through template 210 // instantiation. Therefore checking once during the parse is sufficient. 211 if (!SemaRef.ActiveTemplateInstantiations.empty()) 212 return false; 213 214 Scope *S = SemaRef.getCurScope(); 215 while (S && !S->isSEHExceptScope()) 216 S = S->getParent(); 217 if (!S || !(S->getFlags() & NeededScopeFlags)) { 218 auto *DRE = cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts()); 219 SemaRef.Diag(TheCall->getExprLoc(), DiagID) 220 << DRE->getDecl()->getIdentifier(); 221 return true; 222 } 223 224 return false; 225 } 226 227 ExprResult 228 Sema::CheckBuiltinFunctionCall(FunctionDecl *FDecl, unsigned BuiltinID, 229 CallExpr *TheCall) { 230 ExprResult TheCallResult(TheCall); 231 232 // Find out if any arguments are required to be integer constant expressions. 233 unsigned ICEArguments = 0; 234 ASTContext::GetBuiltinTypeError Error; 235 Context.GetBuiltinType(BuiltinID, Error, &ICEArguments); 236 if (Error != ASTContext::GE_None) 237 ICEArguments = 0; // Don't diagnose previously diagnosed errors. 238 239 // If any arguments are required to be ICE's, check and diagnose. 240 for (unsigned ArgNo = 0; ICEArguments != 0; ++ArgNo) { 241 // Skip arguments not required to be ICE's. 242 if ((ICEArguments & (1 << ArgNo)) == 0) continue; 243 244 llvm::APSInt Result; 245 if (SemaBuiltinConstantArg(TheCall, ArgNo, Result)) 246 return true; 247 ICEArguments &= ~(1 << ArgNo); 248 } 249 250 switch (BuiltinID) { 251 case Builtin::BI__builtin___CFStringMakeConstantString: 252 assert(TheCall->getNumArgs() == 1 && 253 "Wrong # arguments to builtin CFStringMakeConstantString"); 254 if (CheckObjCString(TheCall->getArg(0))) 255 return ExprError(); 256 break; 257 case Builtin::BI__builtin_stdarg_start: 258 case Builtin::BI__builtin_va_start: 259 if (SemaBuiltinVAStart(TheCall)) 260 return ExprError(); 261 break; 262 case Builtin::BI__va_start: { 263 switch (Context.getTargetInfo().getTriple().getArch()) { 264 case llvm::Triple::arm: 265 case llvm::Triple::thumb: 266 if (SemaBuiltinVAStartARM(TheCall)) 267 return ExprError(); 268 break; 269 default: 270 if (SemaBuiltinVAStart(TheCall)) 271 return ExprError(); 272 break; 273 } 274 break; 275 } 276 case Builtin::BI__builtin_isgreater: 277 case Builtin::BI__builtin_isgreaterequal: 278 case Builtin::BI__builtin_isless: 279 case Builtin::BI__builtin_islessequal: 280 case Builtin::BI__builtin_islessgreater: 281 case Builtin::BI__builtin_isunordered: 282 if (SemaBuiltinUnorderedCompare(TheCall)) 283 return ExprError(); 284 break; 285 case Builtin::BI__builtin_fpclassify: 286 if (SemaBuiltinFPClassification(TheCall, 6)) 287 return ExprError(); 288 break; 289 case Builtin::BI__builtin_isfinite: 290 case Builtin::BI__builtin_isinf: 291 case Builtin::BI__builtin_isinf_sign: 292 case Builtin::BI__builtin_isnan: 293 case Builtin::BI__builtin_isnormal: 294 if (SemaBuiltinFPClassification(TheCall, 1)) 295 return ExprError(); 296 break; 297 case Builtin::BI__builtin_shufflevector: 298 return SemaBuiltinShuffleVector(TheCall); 299 // TheCall will be freed by the smart pointer here, but that's fine, since 300 // SemaBuiltinShuffleVector guts it, but then doesn't release it. 301 case Builtin::BI__builtin_prefetch: 302 if (SemaBuiltinPrefetch(TheCall)) 303 return ExprError(); 304 break; 305 case Builtin::BI__assume: 306 case Builtin::BI__builtin_assume: 307 if (SemaBuiltinAssume(TheCall)) 308 return ExprError(); 309 break; 310 case Builtin::BI__builtin_assume_aligned: 311 if (SemaBuiltinAssumeAligned(TheCall)) 312 return ExprError(); 313 break; 314 case Builtin::BI__builtin_object_size: 315 if (SemaBuiltinConstantArgRange(TheCall, 1, 0, 3)) 316 return ExprError(); 317 break; 318 case Builtin::BI__builtin_longjmp: 319 if (SemaBuiltinLongjmp(TheCall)) 320 return ExprError(); 321 break; 322 323 case Builtin::BI__builtin_classify_type: 324 if (checkArgCount(*this, TheCall, 1)) return true; 325 TheCall->setType(Context.IntTy); 326 break; 327 case Builtin::BI__builtin_constant_p: 328 if (checkArgCount(*this, TheCall, 1)) return true; 329 TheCall->setType(Context.IntTy); 330 break; 331 case Builtin::BI__sync_fetch_and_add: 332 case Builtin::BI__sync_fetch_and_add_1: 333 case Builtin::BI__sync_fetch_and_add_2: 334 case Builtin::BI__sync_fetch_and_add_4: 335 case Builtin::BI__sync_fetch_and_add_8: 336 case Builtin::BI__sync_fetch_and_add_16: 337 case Builtin::BI__sync_fetch_and_sub: 338 case Builtin::BI__sync_fetch_and_sub_1: 339 case Builtin::BI__sync_fetch_and_sub_2: 340 case Builtin::BI__sync_fetch_and_sub_4: 341 case Builtin::BI__sync_fetch_and_sub_8: 342 case Builtin::BI__sync_fetch_and_sub_16: 343 case Builtin::BI__sync_fetch_and_or: 344 case Builtin::BI__sync_fetch_and_or_1: 345 case Builtin::BI__sync_fetch_and_or_2: 346 case Builtin::BI__sync_fetch_and_or_4: 347 case Builtin::BI__sync_fetch_and_or_8: 348 case Builtin::BI__sync_fetch_and_or_16: 349 case Builtin::BI__sync_fetch_and_and: 350 case Builtin::BI__sync_fetch_and_and_1: 351 case Builtin::BI__sync_fetch_and_and_2: 352 case Builtin::BI__sync_fetch_and_and_4: 353 case Builtin::BI__sync_fetch_and_and_8: 354 case Builtin::BI__sync_fetch_and_and_16: 355 case Builtin::BI__sync_fetch_and_xor: 356 case Builtin::BI__sync_fetch_and_xor_1: 357 case Builtin::BI__sync_fetch_and_xor_2: 358 case Builtin::BI__sync_fetch_and_xor_4: 359 case Builtin::BI__sync_fetch_and_xor_8: 360 case Builtin::BI__sync_fetch_and_xor_16: 361 case Builtin::BI__sync_fetch_and_nand: 362 case Builtin::BI__sync_fetch_and_nand_1: 363 case Builtin::BI__sync_fetch_and_nand_2: 364 case Builtin::BI__sync_fetch_and_nand_4: 365 case Builtin::BI__sync_fetch_and_nand_8: 366 case Builtin::BI__sync_fetch_and_nand_16: 367 case Builtin::BI__sync_add_and_fetch: 368 case Builtin::BI__sync_add_and_fetch_1: 369 case Builtin::BI__sync_add_and_fetch_2: 370 case Builtin::BI__sync_add_and_fetch_4: 371 case Builtin::BI__sync_add_and_fetch_8: 372 case Builtin::BI__sync_add_and_fetch_16: 373 case Builtin::BI__sync_sub_and_fetch: 374 case Builtin::BI__sync_sub_and_fetch_1: 375 case Builtin::BI__sync_sub_and_fetch_2: 376 case Builtin::BI__sync_sub_and_fetch_4: 377 case Builtin::BI__sync_sub_and_fetch_8: 378 case Builtin::BI__sync_sub_and_fetch_16: 379 case Builtin::BI__sync_and_and_fetch: 380 case Builtin::BI__sync_and_and_fetch_1: 381 case Builtin::BI__sync_and_and_fetch_2: 382 case Builtin::BI__sync_and_and_fetch_4: 383 case Builtin::BI__sync_and_and_fetch_8: 384 case Builtin::BI__sync_and_and_fetch_16: 385 case Builtin::BI__sync_or_and_fetch: 386 case Builtin::BI__sync_or_and_fetch_1: 387 case Builtin::BI__sync_or_and_fetch_2: 388 case Builtin::BI__sync_or_and_fetch_4: 389 case Builtin::BI__sync_or_and_fetch_8: 390 case Builtin::BI__sync_or_and_fetch_16: 391 case Builtin::BI__sync_xor_and_fetch: 392 case Builtin::BI__sync_xor_and_fetch_1: 393 case Builtin::BI__sync_xor_and_fetch_2: 394 case Builtin::BI__sync_xor_and_fetch_4: 395 case Builtin::BI__sync_xor_and_fetch_8: 396 case Builtin::BI__sync_xor_and_fetch_16: 397 case Builtin::BI__sync_nand_and_fetch: 398 case Builtin::BI__sync_nand_and_fetch_1: 399 case Builtin::BI__sync_nand_and_fetch_2: 400 case Builtin::BI__sync_nand_and_fetch_4: 401 case Builtin::BI__sync_nand_and_fetch_8: 402 case Builtin::BI__sync_nand_and_fetch_16: 403 case Builtin::BI__sync_val_compare_and_swap: 404 case Builtin::BI__sync_val_compare_and_swap_1: 405 case Builtin::BI__sync_val_compare_and_swap_2: 406 case Builtin::BI__sync_val_compare_and_swap_4: 407 case Builtin::BI__sync_val_compare_and_swap_8: 408 case Builtin::BI__sync_val_compare_and_swap_16: 409 case Builtin::BI__sync_bool_compare_and_swap: 410 case Builtin::BI__sync_bool_compare_and_swap_1: 411 case Builtin::BI__sync_bool_compare_and_swap_2: 412 case Builtin::BI__sync_bool_compare_and_swap_4: 413 case Builtin::BI__sync_bool_compare_and_swap_8: 414 case Builtin::BI__sync_bool_compare_and_swap_16: 415 case Builtin::BI__sync_lock_test_and_set: 416 case Builtin::BI__sync_lock_test_and_set_1: 417 case Builtin::BI__sync_lock_test_and_set_2: 418 case Builtin::BI__sync_lock_test_and_set_4: 419 case Builtin::BI__sync_lock_test_and_set_8: 420 case Builtin::BI__sync_lock_test_and_set_16: 421 case Builtin::BI__sync_lock_release: 422 case Builtin::BI__sync_lock_release_1: 423 case Builtin::BI__sync_lock_release_2: 424 case Builtin::BI__sync_lock_release_4: 425 case Builtin::BI__sync_lock_release_8: 426 case Builtin::BI__sync_lock_release_16: 427 case Builtin::BI__sync_swap: 428 case Builtin::BI__sync_swap_1: 429 case Builtin::BI__sync_swap_2: 430 case Builtin::BI__sync_swap_4: 431 case Builtin::BI__sync_swap_8: 432 case Builtin::BI__sync_swap_16: 433 return SemaBuiltinAtomicOverloaded(TheCallResult); 434 #define BUILTIN(ID, TYPE, ATTRS) 435 #define ATOMIC_BUILTIN(ID, TYPE, ATTRS) \ 436 case Builtin::BI##ID: \ 437 return SemaAtomicOpsOverloaded(TheCallResult, AtomicExpr::AO##ID); 438 #include "clang/Basic/Builtins.def" 439 case Builtin::BI__builtin_annotation: 440 if (SemaBuiltinAnnotation(*this, TheCall)) 441 return ExprError(); 442 break; 443 case Builtin::BI__builtin_addressof: 444 if (SemaBuiltinAddressof(*this, TheCall)) 445 return ExprError(); 446 break; 447 case Builtin::BI__builtin_operator_new: 448 case Builtin::BI__builtin_operator_delete: 449 if (!getLangOpts().CPlusPlus) { 450 Diag(TheCall->getExprLoc(), diag::err_builtin_requires_language) 451 << (BuiltinID == Builtin::BI__builtin_operator_new 452 ? "__builtin_operator_new" 453 : "__builtin_operator_delete") 454 << "C++"; 455 return ExprError(); 456 } 457 // CodeGen assumes it can find the global new and delete to call, 458 // so ensure that they are declared. 459 DeclareGlobalNewDelete(); 460 break; 461 462 // check secure string manipulation functions where overflows 463 // are detectable at compile time 464 case Builtin::BI__builtin___memcpy_chk: 465 case Builtin::BI__builtin___memmove_chk: 466 case Builtin::BI__builtin___memset_chk: 467 case Builtin::BI__builtin___strlcat_chk: 468 case Builtin::BI__builtin___strlcpy_chk: 469 case Builtin::BI__builtin___strncat_chk: 470 case Builtin::BI__builtin___strncpy_chk: 471 case Builtin::BI__builtin___stpncpy_chk: 472 SemaBuiltinMemChkCall(*this, FDecl, TheCall, 2, 3); 473 break; 474 case Builtin::BI__builtin___memccpy_chk: 475 SemaBuiltinMemChkCall(*this, FDecl, TheCall, 3, 4); 476 break; 477 case Builtin::BI__builtin___snprintf_chk: 478 case Builtin::BI__builtin___vsnprintf_chk: 479 SemaBuiltinMemChkCall(*this, FDecl, TheCall, 1, 3); 480 break; 481 482 case Builtin::BI__builtin_call_with_static_chain: 483 if (SemaBuiltinCallWithStaticChain(*this, TheCall)) 484 return ExprError(); 485 break; 486 487 case Builtin::BI__exception_code: 488 case Builtin::BI_exception_code: { 489 if (SemaBuiltinSEHScopeCheck(*this, TheCall, Scope::SEHExceptScope, 490 diag::err_seh___except_block)) 491 return ExprError(); 492 break; 493 } 494 case Builtin::BI__exception_info: 495 case Builtin::BI_exception_info: { 496 if (SemaBuiltinSEHScopeCheck(*this, TheCall, Scope::SEHFilterScope, 497 diag::err_seh___except_filter)) 498 return ExprError(); 499 break; 500 } 501 502 } 503 504 // Since the target specific builtins for each arch overlap, only check those 505 // of the arch we are compiling for. 506 if (BuiltinID >= Builtin::FirstTSBuiltin) { 507 switch (Context.getTargetInfo().getTriple().getArch()) { 508 case llvm::Triple::arm: 509 case llvm::Triple::armeb: 510 case llvm::Triple::thumb: 511 case llvm::Triple::thumbeb: 512 if (CheckARMBuiltinFunctionCall(BuiltinID, TheCall)) 513 return ExprError(); 514 break; 515 case llvm::Triple::aarch64: 516 case llvm::Triple::aarch64_be: 517 if (CheckAArch64BuiltinFunctionCall(BuiltinID, TheCall)) 518 return ExprError(); 519 break; 520 case llvm::Triple::mips: 521 case llvm::Triple::mipsel: 522 case llvm::Triple::mips64: 523 case llvm::Triple::mips64el: 524 if (CheckMipsBuiltinFunctionCall(BuiltinID, TheCall)) 525 return ExprError(); 526 break; 527 case llvm::Triple::x86: 528 case llvm::Triple::x86_64: 529 if (CheckX86BuiltinFunctionCall(BuiltinID, TheCall)) 530 return ExprError(); 531 break; 532 default: 533 break; 534 } 535 } 536 537 return TheCallResult; 538 } 539 540 // Get the valid immediate range for the specified NEON type code. 541 static unsigned RFT(unsigned t, bool shift = false, bool ForceQuad = false) { 542 NeonTypeFlags Type(t); 543 int IsQuad = ForceQuad ? true : Type.isQuad(); 544 switch (Type.getEltType()) { 545 case NeonTypeFlags::Int8: 546 case NeonTypeFlags::Poly8: 547 return shift ? 7 : (8 << IsQuad) - 1; 548 case NeonTypeFlags::Int16: 549 case NeonTypeFlags::Poly16: 550 return shift ? 15 : (4 << IsQuad) - 1; 551 case NeonTypeFlags::Int32: 552 return shift ? 31 : (2 << IsQuad) - 1; 553 case NeonTypeFlags::Int64: 554 case NeonTypeFlags::Poly64: 555 return shift ? 63 : (1 << IsQuad) - 1; 556 case NeonTypeFlags::Poly128: 557 return shift ? 127 : (1 << IsQuad) - 1; 558 case NeonTypeFlags::Float16: 559 assert(!shift && "cannot shift float types!"); 560 return (4 << IsQuad) - 1; 561 case NeonTypeFlags::Float32: 562 assert(!shift && "cannot shift float types!"); 563 return (2 << IsQuad) - 1; 564 case NeonTypeFlags::Float64: 565 assert(!shift && "cannot shift float types!"); 566 return (1 << IsQuad) - 1; 567 } 568 llvm_unreachable("Invalid NeonTypeFlag!"); 569 } 570 571 /// getNeonEltType - Return the QualType corresponding to the elements of 572 /// the vector type specified by the NeonTypeFlags. This is used to check 573 /// the pointer arguments for Neon load/store intrinsics. 574 static QualType getNeonEltType(NeonTypeFlags Flags, ASTContext &Context, 575 bool IsPolyUnsigned, bool IsInt64Long) { 576 switch (Flags.getEltType()) { 577 case NeonTypeFlags::Int8: 578 return Flags.isUnsigned() ? Context.UnsignedCharTy : Context.SignedCharTy; 579 case NeonTypeFlags::Int16: 580 return Flags.isUnsigned() ? Context.UnsignedShortTy : Context.ShortTy; 581 case NeonTypeFlags::Int32: 582 return Flags.isUnsigned() ? Context.UnsignedIntTy : Context.IntTy; 583 case NeonTypeFlags::Int64: 584 if (IsInt64Long) 585 return Flags.isUnsigned() ? Context.UnsignedLongTy : Context.LongTy; 586 else 587 return Flags.isUnsigned() ? Context.UnsignedLongLongTy 588 : Context.LongLongTy; 589 case NeonTypeFlags::Poly8: 590 return IsPolyUnsigned ? Context.UnsignedCharTy : Context.SignedCharTy; 591 case NeonTypeFlags::Poly16: 592 return IsPolyUnsigned ? Context.UnsignedShortTy : Context.ShortTy; 593 case NeonTypeFlags::Poly64: 594 return Context.UnsignedLongTy; 595 case NeonTypeFlags::Poly128: 596 break; 597 case NeonTypeFlags::Float16: 598 return Context.HalfTy; 599 case NeonTypeFlags::Float32: 600 return Context.FloatTy; 601 case NeonTypeFlags::Float64: 602 return Context.DoubleTy; 603 } 604 llvm_unreachable("Invalid NeonTypeFlag!"); 605 } 606 607 bool Sema::CheckNeonBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) { 608 llvm::APSInt Result; 609 uint64_t mask = 0; 610 unsigned TV = 0; 611 int PtrArgNum = -1; 612 bool HasConstPtr = false; 613 switch (BuiltinID) { 614 #define GET_NEON_OVERLOAD_CHECK 615 #include "clang/Basic/arm_neon.inc" 616 #undef GET_NEON_OVERLOAD_CHECK 617 } 618 619 // For NEON intrinsics which are overloaded on vector element type, validate 620 // the immediate which specifies which variant to emit. 621 unsigned ImmArg = TheCall->getNumArgs()-1; 622 if (mask) { 623 if (SemaBuiltinConstantArg(TheCall, ImmArg, Result)) 624 return true; 625 626 TV = Result.getLimitedValue(64); 627 if ((TV > 63) || (mask & (1ULL << TV)) == 0) 628 return Diag(TheCall->getLocStart(), diag::err_invalid_neon_type_code) 629 << TheCall->getArg(ImmArg)->getSourceRange(); 630 } 631 632 if (PtrArgNum >= 0) { 633 // Check that pointer arguments have the specified type. 634 Expr *Arg = TheCall->getArg(PtrArgNum); 635 if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(Arg)) 636 Arg = ICE->getSubExpr(); 637 ExprResult RHS = DefaultFunctionArrayLvalueConversion(Arg); 638 QualType RHSTy = RHS.get()->getType(); 639 640 llvm::Triple::ArchType Arch = Context.getTargetInfo().getTriple().getArch(); 641 bool IsPolyUnsigned = Arch == llvm::Triple::aarch64; 642 bool IsInt64Long = 643 Context.getTargetInfo().getInt64Type() == TargetInfo::SignedLong; 644 QualType EltTy = 645 getNeonEltType(NeonTypeFlags(TV), Context, IsPolyUnsigned, IsInt64Long); 646 if (HasConstPtr) 647 EltTy = EltTy.withConst(); 648 QualType LHSTy = Context.getPointerType(EltTy); 649 AssignConvertType ConvTy; 650 ConvTy = CheckSingleAssignmentConstraints(LHSTy, RHS); 651 if (RHS.isInvalid()) 652 return true; 653 if (DiagnoseAssignmentResult(ConvTy, Arg->getLocStart(), LHSTy, RHSTy, 654 RHS.get(), AA_Assigning)) 655 return true; 656 } 657 658 // For NEON intrinsics which take an immediate value as part of the 659 // instruction, range check them here. 660 unsigned i = 0, l = 0, u = 0; 661 switch (BuiltinID) { 662 default: 663 return false; 664 #define GET_NEON_IMMEDIATE_CHECK 665 #include "clang/Basic/arm_neon.inc" 666 #undef GET_NEON_IMMEDIATE_CHECK 667 } 668 669 return SemaBuiltinConstantArgRange(TheCall, i, l, u + l); 670 } 671 672 bool Sema::CheckARMBuiltinExclusiveCall(unsigned BuiltinID, CallExpr *TheCall, 673 unsigned MaxWidth) { 674 assert((BuiltinID == ARM::BI__builtin_arm_ldrex || 675 BuiltinID == ARM::BI__builtin_arm_ldaex || 676 BuiltinID == ARM::BI__builtin_arm_strex || 677 BuiltinID == ARM::BI__builtin_arm_stlex || 678 BuiltinID == AArch64::BI__builtin_arm_ldrex || 679 BuiltinID == AArch64::BI__builtin_arm_ldaex || 680 BuiltinID == AArch64::BI__builtin_arm_strex || 681 BuiltinID == AArch64::BI__builtin_arm_stlex) && 682 "unexpected ARM builtin"); 683 bool IsLdrex = BuiltinID == ARM::BI__builtin_arm_ldrex || 684 BuiltinID == ARM::BI__builtin_arm_ldaex || 685 BuiltinID == AArch64::BI__builtin_arm_ldrex || 686 BuiltinID == AArch64::BI__builtin_arm_ldaex; 687 688 DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts()); 689 690 // Ensure that we have the proper number of arguments. 691 if (checkArgCount(*this, TheCall, IsLdrex ? 1 : 2)) 692 return true; 693 694 // Inspect the pointer argument of the atomic builtin. This should always be 695 // a pointer type, whose element is an integral scalar or pointer type. 696 // Because it is a pointer type, we don't have to worry about any implicit 697 // casts here. 698 Expr *PointerArg = TheCall->getArg(IsLdrex ? 0 : 1); 699 ExprResult PointerArgRes = DefaultFunctionArrayLvalueConversion(PointerArg); 700 if (PointerArgRes.isInvalid()) 701 return true; 702 PointerArg = PointerArgRes.get(); 703 704 const PointerType *pointerType = PointerArg->getType()->getAs<PointerType>(); 705 if (!pointerType) { 706 Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer) 707 << PointerArg->getType() << PointerArg->getSourceRange(); 708 return true; 709 } 710 711 // ldrex takes a "const volatile T*" and strex takes a "volatile T*". Our next 712 // task is to insert the appropriate casts into the AST. First work out just 713 // what the appropriate type is. 714 QualType ValType = pointerType->getPointeeType(); 715 QualType AddrType = ValType.getUnqualifiedType().withVolatile(); 716 if (IsLdrex) 717 AddrType.addConst(); 718 719 // Issue a warning if the cast is dodgy. 720 CastKind CastNeeded = CK_NoOp; 721 if (!AddrType.isAtLeastAsQualifiedAs(ValType)) { 722 CastNeeded = CK_BitCast; 723 Diag(DRE->getLocStart(), diag::ext_typecheck_convert_discards_qualifiers) 724 << PointerArg->getType() 725 << Context.getPointerType(AddrType) 726 << AA_Passing << PointerArg->getSourceRange(); 727 } 728 729 // Finally, do the cast and replace the argument with the corrected version. 730 AddrType = Context.getPointerType(AddrType); 731 PointerArgRes = ImpCastExprToType(PointerArg, AddrType, CastNeeded); 732 if (PointerArgRes.isInvalid()) 733 return true; 734 PointerArg = PointerArgRes.get(); 735 736 TheCall->setArg(IsLdrex ? 0 : 1, PointerArg); 737 738 // In general, we allow ints, floats and pointers to be loaded and stored. 739 if (!ValType->isIntegerType() && !ValType->isAnyPointerType() && 740 !ValType->isBlockPointerType() && !ValType->isFloatingType()) { 741 Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer_intfltptr) 742 << PointerArg->getType() << PointerArg->getSourceRange(); 743 return true; 744 } 745 746 // But ARM doesn't have instructions to deal with 128-bit versions. 747 if (Context.getTypeSize(ValType) > MaxWidth) { 748 assert(MaxWidth == 64 && "Diagnostic unexpectedly inaccurate"); 749 Diag(DRE->getLocStart(), diag::err_atomic_exclusive_builtin_pointer_size) 750 << PointerArg->getType() << PointerArg->getSourceRange(); 751 return true; 752 } 753 754 switch (ValType.getObjCLifetime()) { 755 case Qualifiers::OCL_None: 756 case Qualifiers::OCL_ExplicitNone: 757 // okay 758 break; 759 760 case Qualifiers::OCL_Weak: 761 case Qualifiers::OCL_Strong: 762 case Qualifiers::OCL_Autoreleasing: 763 Diag(DRE->getLocStart(), diag::err_arc_atomic_ownership) 764 << ValType << PointerArg->getSourceRange(); 765 return true; 766 } 767 768 769 if (IsLdrex) { 770 TheCall->setType(ValType); 771 return false; 772 } 773 774 // Initialize the argument to be stored. 775 ExprResult ValArg = TheCall->getArg(0); 776 InitializedEntity Entity = InitializedEntity::InitializeParameter( 777 Context, ValType, /*consume*/ false); 778 ValArg = PerformCopyInitialization(Entity, SourceLocation(), ValArg); 779 if (ValArg.isInvalid()) 780 return true; 781 TheCall->setArg(0, ValArg.get()); 782 783 // __builtin_arm_strex always returns an int. It's marked as such in the .def, 784 // but the custom checker bypasses all default analysis. 785 TheCall->setType(Context.IntTy); 786 return false; 787 } 788 789 bool Sema::CheckARMBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) { 790 llvm::APSInt Result; 791 792 if (BuiltinID == ARM::BI__builtin_arm_ldrex || 793 BuiltinID == ARM::BI__builtin_arm_ldaex || 794 BuiltinID == ARM::BI__builtin_arm_strex || 795 BuiltinID == ARM::BI__builtin_arm_stlex) { 796 return CheckARMBuiltinExclusiveCall(BuiltinID, TheCall, 64); 797 } 798 799 if (BuiltinID == ARM::BI__builtin_arm_prefetch) { 800 return SemaBuiltinConstantArgRange(TheCall, 1, 0, 1) || 801 SemaBuiltinConstantArgRange(TheCall, 2, 0, 1); 802 } 803 804 if (CheckNeonBuiltinFunctionCall(BuiltinID, TheCall)) 805 return true; 806 807 // For intrinsics which take an immediate value as part of the instruction, 808 // range check them here. 809 unsigned i = 0, l = 0, u = 0; 810 switch (BuiltinID) { 811 default: return false; 812 case ARM::BI__builtin_arm_ssat: i = 1; l = 1; u = 31; break; 813 case ARM::BI__builtin_arm_usat: i = 1; u = 31; break; 814 case ARM::BI__builtin_arm_vcvtr_f: 815 case ARM::BI__builtin_arm_vcvtr_d: i = 1; u = 1; break; 816 case ARM::BI__builtin_arm_dmb: 817 case ARM::BI__builtin_arm_dsb: 818 case ARM::BI__builtin_arm_isb: 819 case ARM::BI__builtin_arm_dbg: l = 0; u = 15; break; 820 } 821 822 // FIXME: VFP Intrinsics should error if VFP not present. 823 return SemaBuiltinConstantArgRange(TheCall, i, l, u + l); 824 } 825 826 bool Sema::CheckAArch64BuiltinFunctionCall(unsigned BuiltinID, 827 CallExpr *TheCall) { 828 llvm::APSInt Result; 829 830 if (BuiltinID == AArch64::BI__builtin_arm_ldrex || 831 BuiltinID == AArch64::BI__builtin_arm_ldaex || 832 BuiltinID == AArch64::BI__builtin_arm_strex || 833 BuiltinID == AArch64::BI__builtin_arm_stlex) { 834 return CheckARMBuiltinExclusiveCall(BuiltinID, TheCall, 128); 835 } 836 837 if (BuiltinID == AArch64::BI__builtin_arm_prefetch) { 838 return SemaBuiltinConstantArgRange(TheCall, 1, 0, 1) || 839 SemaBuiltinConstantArgRange(TheCall, 2, 0, 2) || 840 SemaBuiltinConstantArgRange(TheCall, 3, 0, 1) || 841 SemaBuiltinConstantArgRange(TheCall, 4, 0, 1); 842 } 843 844 if (CheckNeonBuiltinFunctionCall(BuiltinID, TheCall)) 845 return true; 846 847 // For intrinsics which take an immediate value as part of the instruction, 848 // range check them here. 849 unsigned i = 0, l = 0, u = 0; 850 switch (BuiltinID) { 851 default: return false; 852 case AArch64::BI__builtin_arm_dmb: 853 case AArch64::BI__builtin_arm_dsb: 854 case AArch64::BI__builtin_arm_isb: l = 0; u = 15; break; 855 } 856 857 return SemaBuiltinConstantArgRange(TheCall, i, l, u + l); 858 } 859 860 bool Sema::CheckMipsBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) { 861 unsigned i = 0, l = 0, u = 0; 862 switch (BuiltinID) { 863 default: return false; 864 case Mips::BI__builtin_mips_wrdsp: i = 1; l = 0; u = 63; break; 865 case Mips::BI__builtin_mips_rddsp: i = 0; l = 0; u = 63; break; 866 case Mips::BI__builtin_mips_append: i = 2; l = 0; u = 31; break; 867 case Mips::BI__builtin_mips_balign: i = 2; l = 0; u = 3; break; 868 case Mips::BI__builtin_mips_precr_sra_ph_w: i = 2; l = 0; u = 31; break; 869 case Mips::BI__builtin_mips_precr_sra_r_ph_w: i = 2; l = 0; u = 31; break; 870 case Mips::BI__builtin_mips_prepend: i = 2; l = 0; u = 31; break; 871 } 872 873 return SemaBuiltinConstantArgRange(TheCall, i, l, u); 874 } 875 876 bool Sema::CheckX86BuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) { 877 unsigned i = 0, l = 0, u = 0; 878 switch (BuiltinID) { 879 default: return false; 880 case X86::BI_mm_prefetch: i = 1; l = 0; u = 3; break; 881 case X86::BI__builtin_ia32_vextractf128_pd256: 882 case X86::BI__builtin_ia32_vextractf128_ps256: 883 case X86::BI__builtin_ia32_vextractf128_si256: 884 case X86::BI__builtin_ia32_extract128i256: i = 1, l = 0, u = 1; break; 885 case X86::BI__builtin_ia32_vinsertf128_pd256: 886 case X86::BI__builtin_ia32_vinsertf128_ps256: 887 case X86::BI__builtin_ia32_vinsertf128_si256: 888 case X86::BI__builtin_ia32_insert128i256: 889 case X86::BI__builtin_ia32_blendpd: i = 2, l = 0; u = 1; break; 890 case X86::BI__builtin_ia32_blendps: 891 case X86::BI__builtin_ia32_blendpd256: 892 case X86::BI__builtin_ia32_sha1rnds4: i = 2, l = 0; u = 3; break; 893 case X86::BI__builtin_ia32_vpermil2pd: 894 case X86::BI__builtin_ia32_vpermil2pd256: 895 case X86::BI__builtin_ia32_vpermil2ps: 896 case X86::BI__builtin_ia32_vpermil2ps256: i = 3, l = 0; u = 3; break; 897 case X86::BI__builtin_ia32_cmpb128_mask: 898 case X86::BI__builtin_ia32_cmpw128_mask: 899 case X86::BI__builtin_ia32_cmpd128_mask: 900 case X86::BI__builtin_ia32_cmpq128_mask: 901 case X86::BI__builtin_ia32_cmpb256_mask: 902 case X86::BI__builtin_ia32_cmpw256_mask: 903 case X86::BI__builtin_ia32_cmpd256_mask: 904 case X86::BI__builtin_ia32_cmpq256_mask: 905 case X86::BI__builtin_ia32_cmpb512_mask: 906 case X86::BI__builtin_ia32_cmpw512_mask: 907 case X86::BI__builtin_ia32_cmpd512_mask: 908 case X86::BI__builtin_ia32_cmpq512_mask: 909 case X86::BI__builtin_ia32_ucmpb128_mask: 910 case X86::BI__builtin_ia32_ucmpw128_mask: 911 case X86::BI__builtin_ia32_ucmpd128_mask: 912 case X86::BI__builtin_ia32_ucmpq128_mask: 913 case X86::BI__builtin_ia32_ucmpb256_mask: 914 case X86::BI__builtin_ia32_ucmpw256_mask: 915 case X86::BI__builtin_ia32_ucmpd256_mask: 916 case X86::BI__builtin_ia32_ucmpq256_mask: 917 case X86::BI__builtin_ia32_ucmpb512_mask: 918 case X86::BI__builtin_ia32_ucmpw512_mask: 919 case X86::BI__builtin_ia32_ucmpd512_mask: 920 case X86::BI__builtin_ia32_ucmpq512_mask: i = 2; l = 0; u = 7; break; 921 case X86::BI__builtin_ia32_roundps: 922 case X86::BI__builtin_ia32_roundpd: 923 case X86::BI__builtin_ia32_roundps256: 924 case X86::BI__builtin_ia32_roundpd256: i = 1, l = 0; u = 15; break; 925 case X86::BI__builtin_ia32_roundss: 926 case X86::BI__builtin_ia32_roundsd: i = 2, l = 0; u = 15; break; 927 case X86::BI__builtin_ia32_cmpps: 928 case X86::BI__builtin_ia32_cmpss: 929 case X86::BI__builtin_ia32_cmppd: 930 case X86::BI__builtin_ia32_cmpsd: 931 case X86::BI__builtin_ia32_cmpps256: 932 case X86::BI__builtin_ia32_cmppd256: 933 case X86::BI__builtin_ia32_cmpps512_mask: 934 case X86::BI__builtin_ia32_cmppd512_mask: i = 2; l = 0; u = 31; break; 935 case X86::BI__builtin_ia32_vpcomub: 936 case X86::BI__builtin_ia32_vpcomuw: 937 case X86::BI__builtin_ia32_vpcomud: 938 case X86::BI__builtin_ia32_vpcomuq: 939 case X86::BI__builtin_ia32_vpcomb: 940 case X86::BI__builtin_ia32_vpcomw: 941 case X86::BI__builtin_ia32_vpcomd: 942 case X86::BI__builtin_ia32_vpcomq: i = 2; l = 0; u = 7; break; 943 } 944 return SemaBuiltinConstantArgRange(TheCall, i, l, u); 945 } 946 947 /// Given a FunctionDecl's FormatAttr, attempts to populate the FomatStringInfo 948 /// parameter with the FormatAttr's correct format_idx and firstDataArg. 949 /// Returns true when the format fits the function and the FormatStringInfo has 950 /// been populated. 951 bool Sema::getFormatStringInfo(const FormatAttr *Format, bool IsCXXMember, 952 FormatStringInfo *FSI) { 953 FSI->HasVAListArg = Format->getFirstArg() == 0; 954 FSI->FormatIdx = Format->getFormatIdx() - 1; 955 FSI->FirstDataArg = FSI->HasVAListArg ? 0 : Format->getFirstArg() - 1; 956 957 // The way the format attribute works in GCC, the implicit this argument 958 // of member functions is counted. However, it doesn't appear in our own 959 // lists, so decrement format_idx in that case. 960 if (IsCXXMember) { 961 if(FSI->FormatIdx == 0) 962 return false; 963 --FSI->FormatIdx; 964 if (FSI->FirstDataArg != 0) 965 --FSI->FirstDataArg; 966 } 967 return true; 968 } 969 970 /// Checks if a the given expression evaluates to null. 971 /// 972 /// \brief Returns true if the value evaluates to null. 973 static bool CheckNonNullExpr(Sema &S, 974 const Expr *Expr) { 975 // As a special case, transparent unions initialized with zero are 976 // considered null for the purposes of the nonnull attribute. 977 if (const RecordType *UT = Expr->getType()->getAsUnionType()) { 978 if (UT->getDecl()->hasAttr<TransparentUnionAttr>()) 979 if (const CompoundLiteralExpr *CLE = 980 dyn_cast<CompoundLiteralExpr>(Expr)) 981 if (const InitListExpr *ILE = 982 dyn_cast<InitListExpr>(CLE->getInitializer())) 983 Expr = ILE->getInit(0); 984 } 985 986 bool Result; 987 return (!Expr->isValueDependent() && 988 Expr->EvaluateAsBooleanCondition(Result, S.Context) && 989 !Result); 990 } 991 992 static void CheckNonNullArgument(Sema &S, 993 const Expr *ArgExpr, 994 SourceLocation CallSiteLoc) { 995 if (CheckNonNullExpr(S, ArgExpr)) 996 S.Diag(CallSiteLoc, diag::warn_null_arg) << ArgExpr->getSourceRange(); 997 } 998 999 bool Sema::GetFormatNSStringIdx(const FormatAttr *Format, unsigned &Idx) { 1000 FormatStringInfo FSI; 1001 if ((GetFormatStringType(Format) == FST_NSString) && 1002 getFormatStringInfo(Format, false, &FSI)) { 1003 Idx = FSI.FormatIdx; 1004 return true; 1005 } 1006 return false; 1007 } 1008 /// \brief Diagnose use of %s directive in an NSString which is being passed 1009 /// as formatting string to formatting method. 1010 static void 1011 DiagnoseCStringFormatDirectiveInCFAPI(Sema &S, 1012 const NamedDecl *FDecl, 1013 Expr **Args, 1014 unsigned NumArgs) { 1015 unsigned Idx = 0; 1016 bool Format = false; 1017 ObjCStringFormatFamily SFFamily = FDecl->getObjCFStringFormattingFamily(); 1018 if (SFFamily == ObjCStringFormatFamily::SFF_CFString) { 1019 Idx = 2; 1020 Format = true; 1021 } 1022 else 1023 for (const auto *I : FDecl->specific_attrs<FormatAttr>()) { 1024 if (S.GetFormatNSStringIdx(I, Idx)) { 1025 Format = true; 1026 break; 1027 } 1028 } 1029 if (!Format || NumArgs <= Idx) 1030 return; 1031 const Expr *FormatExpr = Args[Idx]; 1032 if (const CStyleCastExpr *CSCE = dyn_cast<CStyleCastExpr>(FormatExpr)) 1033 FormatExpr = CSCE->getSubExpr(); 1034 const StringLiteral *FormatString; 1035 if (const ObjCStringLiteral *OSL = 1036 dyn_cast<ObjCStringLiteral>(FormatExpr->IgnoreParenImpCasts())) 1037 FormatString = OSL->getString(); 1038 else 1039 FormatString = dyn_cast<StringLiteral>(FormatExpr->IgnoreParenImpCasts()); 1040 if (!FormatString) 1041 return; 1042 if (S.FormatStringHasSArg(FormatString)) { 1043 S.Diag(FormatExpr->getExprLoc(), diag::warn_objc_cdirective_format_string) 1044 << "%s" << 1 << 1; 1045 S.Diag(FDecl->getLocation(), diag::note_entity_declared_at) 1046 << FDecl->getDeclName(); 1047 } 1048 } 1049 1050 static void CheckNonNullArguments(Sema &S, 1051 const NamedDecl *FDecl, 1052 ArrayRef<const Expr *> Args, 1053 SourceLocation CallSiteLoc) { 1054 // Check the attributes attached to the method/function itself. 1055 llvm::SmallBitVector NonNullArgs; 1056 for (const auto *NonNull : FDecl->specific_attrs<NonNullAttr>()) { 1057 if (!NonNull->args_size()) { 1058 // Easy case: all pointer arguments are nonnull. 1059 for (const auto *Arg : Args) 1060 if (S.isValidPointerAttrType(Arg->getType())) 1061 CheckNonNullArgument(S, Arg, CallSiteLoc); 1062 return; 1063 } 1064 1065 for (unsigned Val : NonNull->args()) { 1066 if (Val >= Args.size()) 1067 continue; 1068 if (NonNullArgs.empty()) 1069 NonNullArgs.resize(Args.size()); 1070 NonNullArgs.set(Val); 1071 } 1072 } 1073 1074 // Check the attributes on the parameters. 1075 ArrayRef<ParmVarDecl*> parms; 1076 if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(FDecl)) 1077 parms = FD->parameters(); 1078 else if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(FDecl)) 1079 parms = MD->parameters(); 1080 1081 unsigned ArgIndex = 0; 1082 for (ArrayRef<ParmVarDecl*>::iterator I = parms.begin(), E = parms.end(); 1083 I != E; ++I, ++ArgIndex) { 1084 const ParmVarDecl *PVD = *I; 1085 if (PVD->hasAttr<NonNullAttr>() || 1086 (ArgIndex < NonNullArgs.size() && NonNullArgs[ArgIndex])) 1087 CheckNonNullArgument(S, Args[ArgIndex], CallSiteLoc); 1088 } 1089 1090 // In case this is a variadic call, check any remaining arguments. 1091 for (/**/; ArgIndex < NonNullArgs.size(); ++ArgIndex) 1092 if (NonNullArgs[ArgIndex]) 1093 CheckNonNullArgument(S, Args[ArgIndex], CallSiteLoc); 1094 } 1095 1096 /// Handles the checks for format strings, non-POD arguments to vararg 1097 /// functions, and NULL arguments passed to non-NULL parameters. 1098 void Sema::checkCall(NamedDecl *FDecl, ArrayRef<const Expr *> Args, 1099 unsigned NumParams, bool IsMemberFunction, 1100 SourceLocation Loc, SourceRange Range, 1101 VariadicCallType CallType) { 1102 // FIXME: We should check as much as we can in the template definition. 1103 if (CurContext->isDependentContext()) 1104 return; 1105 1106 // Printf and scanf checking. 1107 llvm::SmallBitVector CheckedVarArgs; 1108 if (FDecl) { 1109 for (const auto *I : FDecl->specific_attrs<FormatAttr>()) { 1110 // Only create vector if there are format attributes. 1111 CheckedVarArgs.resize(Args.size()); 1112 1113 CheckFormatArguments(I, Args, IsMemberFunction, CallType, Loc, Range, 1114 CheckedVarArgs); 1115 } 1116 } 1117 1118 // Refuse POD arguments that weren't caught by the format string 1119 // checks above. 1120 if (CallType != VariadicDoesNotApply) { 1121 for (unsigned ArgIdx = NumParams; ArgIdx < Args.size(); ++ArgIdx) { 1122 // Args[ArgIdx] can be null in malformed code. 1123 if (const Expr *Arg = Args[ArgIdx]) { 1124 if (CheckedVarArgs.empty() || !CheckedVarArgs[ArgIdx]) 1125 checkVariadicArgument(Arg, CallType); 1126 } 1127 } 1128 } 1129 1130 if (FDecl) { 1131 CheckNonNullArguments(*this, FDecl, Args, Loc); 1132 1133 // Type safety checking. 1134 for (const auto *I : FDecl->specific_attrs<ArgumentWithTypeTagAttr>()) 1135 CheckArgumentWithTypeTag(I, Args.data()); 1136 } 1137 } 1138 1139 /// CheckConstructorCall - Check a constructor call for correctness and safety 1140 /// properties not enforced by the C type system. 1141 void Sema::CheckConstructorCall(FunctionDecl *FDecl, 1142 ArrayRef<const Expr *> Args, 1143 const FunctionProtoType *Proto, 1144 SourceLocation Loc) { 1145 VariadicCallType CallType = 1146 Proto->isVariadic() ? VariadicConstructor : VariadicDoesNotApply; 1147 checkCall(FDecl, Args, Proto->getNumParams(), 1148 /*IsMemberFunction=*/true, Loc, SourceRange(), CallType); 1149 } 1150 1151 /// CheckFunctionCall - Check a direct function call for various correctness 1152 /// and safety properties not strictly enforced by the C type system. 1153 bool Sema::CheckFunctionCall(FunctionDecl *FDecl, CallExpr *TheCall, 1154 const FunctionProtoType *Proto) { 1155 bool IsMemberOperatorCall = isa<CXXOperatorCallExpr>(TheCall) && 1156 isa<CXXMethodDecl>(FDecl); 1157 bool IsMemberFunction = isa<CXXMemberCallExpr>(TheCall) || 1158 IsMemberOperatorCall; 1159 VariadicCallType CallType = getVariadicCallType(FDecl, Proto, 1160 TheCall->getCallee()); 1161 unsigned NumParams = Proto ? Proto->getNumParams() : 0; 1162 Expr** Args = TheCall->getArgs(); 1163 unsigned NumArgs = TheCall->getNumArgs(); 1164 if (IsMemberOperatorCall) { 1165 // If this is a call to a member operator, hide the first argument 1166 // from checkCall. 1167 // FIXME: Our choice of AST representation here is less than ideal. 1168 ++Args; 1169 --NumArgs; 1170 } 1171 checkCall(FDecl, llvm::makeArrayRef(Args, NumArgs), NumParams, 1172 IsMemberFunction, TheCall->getRParenLoc(), 1173 TheCall->getCallee()->getSourceRange(), CallType); 1174 1175 IdentifierInfo *FnInfo = FDecl->getIdentifier(); 1176 // None of the checks below are needed for functions that don't have 1177 // simple names (e.g., C++ conversion functions). 1178 if (!FnInfo) 1179 return false; 1180 1181 CheckAbsoluteValueFunction(TheCall, FDecl, FnInfo); 1182 if (getLangOpts().ObjC1) 1183 DiagnoseCStringFormatDirectiveInCFAPI(*this, FDecl, Args, NumArgs); 1184 1185 unsigned CMId = FDecl->getMemoryFunctionKind(); 1186 if (CMId == 0) 1187 return false; 1188 1189 // Handle memory setting and copying functions. 1190 if (CMId == Builtin::BIstrlcpy || CMId == Builtin::BIstrlcat) 1191 CheckStrlcpycatArguments(TheCall, FnInfo); 1192 else if (CMId == Builtin::BIstrncat) 1193 CheckStrncatArguments(TheCall, FnInfo); 1194 else 1195 CheckMemaccessArguments(TheCall, CMId, FnInfo); 1196 1197 return false; 1198 } 1199 1200 bool Sema::CheckObjCMethodCall(ObjCMethodDecl *Method, SourceLocation lbrac, 1201 ArrayRef<const Expr *> Args) { 1202 VariadicCallType CallType = 1203 Method->isVariadic() ? VariadicMethod : VariadicDoesNotApply; 1204 1205 checkCall(Method, Args, Method->param_size(), 1206 /*IsMemberFunction=*/false, 1207 lbrac, Method->getSourceRange(), CallType); 1208 1209 return false; 1210 } 1211 1212 bool Sema::CheckPointerCall(NamedDecl *NDecl, CallExpr *TheCall, 1213 const FunctionProtoType *Proto) { 1214 const VarDecl *V = dyn_cast<VarDecl>(NDecl); 1215 if (!V) 1216 return false; 1217 1218 QualType Ty = V->getType(); 1219 if (!Ty->isBlockPointerType() && !Ty->isFunctionPointerType()) 1220 return false; 1221 1222 VariadicCallType CallType; 1223 if (!Proto || !Proto->isVariadic()) { 1224 CallType = VariadicDoesNotApply; 1225 } else if (Ty->isBlockPointerType()) { 1226 CallType = VariadicBlock; 1227 } else { // Ty->isFunctionPointerType() 1228 CallType = VariadicFunction; 1229 } 1230 unsigned NumParams = Proto ? Proto->getNumParams() : 0; 1231 1232 checkCall(NDecl, llvm::makeArrayRef(TheCall->getArgs(), 1233 TheCall->getNumArgs()), 1234 NumParams, /*IsMemberFunction=*/false, TheCall->getRParenLoc(), 1235 TheCall->getCallee()->getSourceRange(), CallType); 1236 1237 return false; 1238 } 1239 1240 /// Checks function calls when a FunctionDecl or a NamedDecl is not available, 1241 /// such as function pointers returned from functions. 1242 bool Sema::CheckOtherCall(CallExpr *TheCall, const FunctionProtoType *Proto) { 1243 VariadicCallType CallType = getVariadicCallType(/*FDecl=*/nullptr, Proto, 1244 TheCall->getCallee()); 1245 unsigned NumParams = Proto ? Proto->getNumParams() : 0; 1246 1247 checkCall(/*FDecl=*/nullptr, 1248 llvm::makeArrayRef(TheCall->getArgs(), TheCall->getNumArgs()), 1249 NumParams, /*IsMemberFunction=*/false, TheCall->getRParenLoc(), 1250 TheCall->getCallee()->getSourceRange(), CallType); 1251 1252 return false; 1253 } 1254 1255 static bool isValidOrderingForOp(int64_t Ordering, AtomicExpr::AtomicOp Op) { 1256 if (Ordering < AtomicExpr::AO_ABI_memory_order_relaxed || 1257 Ordering > AtomicExpr::AO_ABI_memory_order_seq_cst) 1258 return false; 1259 1260 switch (Op) { 1261 case AtomicExpr::AO__c11_atomic_init: 1262 llvm_unreachable("There is no ordering argument for an init"); 1263 1264 case AtomicExpr::AO__c11_atomic_load: 1265 case AtomicExpr::AO__atomic_load_n: 1266 case AtomicExpr::AO__atomic_load: 1267 return Ordering != AtomicExpr::AO_ABI_memory_order_release && 1268 Ordering != AtomicExpr::AO_ABI_memory_order_acq_rel; 1269 1270 case AtomicExpr::AO__c11_atomic_store: 1271 case AtomicExpr::AO__atomic_store: 1272 case AtomicExpr::AO__atomic_store_n: 1273 return Ordering != AtomicExpr::AO_ABI_memory_order_consume && 1274 Ordering != AtomicExpr::AO_ABI_memory_order_acquire && 1275 Ordering != AtomicExpr::AO_ABI_memory_order_acq_rel; 1276 1277 default: 1278 return true; 1279 } 1280 } 1281 1282 ExprResult Sema::SemaAtomicOpsOverloaded(ExprResult TheCallResult, 1283 AtomicExpr::AtomicOp Op) { 1284 CallExpr *TheCall = cast<CallExpr>(TheCallResult.get()); 1285 DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts()); 1286 1287 // All these operations take one of the following forms: 1288 enum { 1289 // C __c11_atomic_init(A *, C) 1290 Init, 1291 // C __c11_atomic_load(A *, int) 1292 Load, 1293 // void __atomic_load(A *, CP, int) 1294 Copy, 1295 // C __c11_atomic_add(A *, M, int) 1296 Arithmetic, 1297 // C __atomic_exchange_n(A *, CP, int) 1298 Xchg, 1299 // void __atomic_exchange(A *, C *, CP, int) 1300 GNUXchg, 1301 // bool __c11_atomic_compare_exchange_strong(A *, C *, CP, int, int) 1302 C11CmpXchg, 1303 // bool __atomic_compare_exchange(A *, C *, CP, bool, int, int) 1304 GNUCmpXchg 1305 } Form = Init; 1306 const unsigned NumArgs[] = { 2, 2, 3, 3, 3, 4, 5, 6 }; 1307 const unsigned NumVals[] = { 1, 0, 1, 1, 1, 2, 2, 3 }; 1308 // where: 1309 // C is an appropriate type, 1310 // A is volatile _Atomic(C) for __c11 builtins and is C for GNU builtins, 1311 // CP is C for __c11 builtins and GNU _n builtins and is C * otherwise, 1312 // M is C if C is an integer, and ptrdiff_t if C is a pointer, and 1313 // the int parameters are for orderings. 1314 1315 assert(AtomicExpr::AO__c11_atomic_init == 0 && 1316 AtomicExpr::AO__c11_atomic_fetch_xor + 1 == AtomicExpr::AO__atomic_load 1317 && "need to update code for modified C11 atomics"); 1318 bool IsC11 = Op >= AtomicExpr::AO__c11_atomic_init && 1319 Op <= AtomicExpr::AO__c11_atomic_fetch_xor; 1320 bool IsN = Op == AtomicExpr::AO__atomic_load_n || 1321 Op == AtomicExpr::AO__atomic_store_n || 1322 Op == AtomicExpr::AO__atomic_exchange_n || 1323 Op == AtomicExpr::AO__atomic_compare_exchange_n; 1324 bool IsAddSub = false; 1325 1326 switch (Op) { 1327 case AtomicExpr::AO__c11_atomic_init: 1328 Form = Init; 1329 break; 1330 1331 case AtomicExpr::AO__c11_atomic_load: 1332 case AtomicExpr::AO__atomic_load_n: 1333 Form = Load; 1334 break; 1335 1336 case AtomicExpr::AO__c11_atomic_store: 1337 case AtomicExpr::AO__atomic_load: 1338 case AtomicExpr::AO__atomic_store: 1339 case AtomicExpr::AO__atomic_store_n: 1340 Form = Copy; 1341 break; 1342 1343 case AtomicExpr::AO__c11_atomic_fetch_add: 1344 case AtomicExpr::AO__c11_atomic_fetch_sub: 1345 case AtomicExpr::AO__atomic_fetch_add: 1346 case AtomicExpr::AO__atomic_fetch_sub: 1347 case AtomicExpr::AO__atomic_add_fetch: 1348 case AtomicExpr::AO__atomic_sub_fetch: 1349 IsAddSub = true; 1350 // Fall through. 1351 case AtomicExpr::AO__c11_atomic_fetch_and: 1352 case AtomicExpr::AO__c11_atomic_fetch_or: 1353 case AtomicExpr::AO__c11_atomic_fetch_xor: 1354 case AtomicExpr::AO__atomic_fetch_and: 1355 case AtomicExpr::AO__atomic_fetch_or: 1356 case AtomicExpr::AO__atomic_fetch_xor: 1357 case AtomicExpr::AO__atomic_fetch_nand: 1358 case AtomicExpr::AO__atomic_and_fetch: 1359 case AtomicExpr::AO__atomic_or_fetch: 1360 case AtomicExpr::AO__atomic_xor_fetch: 1361 case AtomicExpr::AO__atomic_nand_fetch: 1362 Form = Arithmetic; 1363 break; 1364 1365 case AtomicExpr::AO__c11_atomic_exchange: 1366 case AtomicExpr::AO__atomic_exchange_n: 1367 Form = Xchg; 1368 break; 1369 1370 case AtomicExpr::AO__atomic_exchange: 1371 Form = GNUXchg; 1372 break; 1373 1374 case AtomicExpr::AO__c11_atomic_compare_exchange_strong: 1375 case AtomicExpr::AO__c11_atomic_compare_exchange_weak: 1376 Form = C11CmpXchg; 1377 break; 1378 1379 case AtomicExpr::AO__atomic_compare_exchange: 1380 case AtomicExpr::AO__atomic_compare_exchange_n: 1381 Form = GNUCmpXchg; 1382 break; 1383 } 1384 1385 // Check we have the right number of arguments. 1386 if (TheCall->getNumArgs() < NumArgs[Form]) { 1387 Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args) 1388 << 0 << NumArgs[Form] << TheCall->getNumArgs() 1389 << TheCall->getCallee()->getSourceRange(); 1390 return ExprError(); 1391 } else if (TheCall->getNumArgs() > NumArgs[Form]) { 1392 Diag(TheCall->getArg(NumArgs[Form])->getLocStart(), 1393 diag::err_typecheck_call_too_many_args) 1394 << 0 << NumArgs[Form] << TheCall->getNumArgs() 1395 << TheCall->getCallee()->getSourceRange(); 1396 return ExprError(); 1397 } 1398 1399 // Inspect the first argument of the atomic operation. 1400 Expr *Ptr = TheCall->getArg(0); 1401 Ptr = DefaultFunctionArrayLvalueConversion(Ptr).get(); 1402 const PointerType *pointerType = Ptr->getType()->getAs<PointerType>(); 1403 if (!pointerType) { 1404 Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer) 1405 << Ptr->getType() << Ptr->getSourceRange(); 1406 return ExprError(); 1407 } 1408 1409 // For a __c11 builtin, this should be a pointer to an _Atomic type. 1410 QualType AtomTy = pointerType->getPointeeType(); // 'A' 1411 QualType ValType = AtomTy; // 'C' 1412 if (IsC11) { 1413 if (!AtomTy->isAtomicType()) { 1414 Diag(DRE->getLocStart(), diag::err_atomic_op_needs_atomic) 1415 << Ptr->getType() << Ptr->getSourceRange(); 1416 return ExprError(); 1417 } 1418 if (AtomTy.isConstQualified()) { 1419 Diag(DRE->getLocStart(), diag::err_atomic_op_needs_non_const_atomic) 1420 << Ptr->getType() << Ptr->getSourceRange(); 1421 return ExprError(); 1422 } 1423 ValType = AtomTy->getAs<AtomicType>()->getValueType(); 1424 } 1425 1426 // For an arithmetic operation, the implied arithmetic must be well-formed. 1427 if (Form == Arithmetic) { 1428 // gcc does not enforce these rules for GNU atomics, but we do so for sanity. 1429 if (IsAddSub && !ValType->isIntegerType() && !ValType->isPointerType()) { 1430 Diag(DRE->getLocStart(), diag::err_atomic_op_needs_atomic_int_or_ptr) 1431 << IsC11 << Ptr->getType() << Ptr->getSourceRange(); 1432 return ExprError(); 1433 } 1434 if (!IsAddSub && !ValType->isIntegerType()) { 1435 Diag(DRE->getLocStart(), diag::err_atomic_op_bitwise_needs_atomic_int) 1436 << IsC11 << Ptr->getType() << Ptr->getSourceRange(); 1437 return ExprError(); 1438 } 1439 if (IsC11 && ValType->isPointerType() && 1440 RequireCompleteType(Ptr->getLocStart(), ValType->getPointeeType(), 1441 diag::err_incomplete_type)) { 1442 return ExprError(); 1443 } 1444 } else if (IsN && !ValType->isIntegerType() && !ValType->isPointerType()) { 1445 // For __atomic_*_n operations, the value type must be a scalar integral or 1446 // pointer type which is 1, 2, 4, 8 or 16 bytes in length. 1447 Diag(DRE->getLocStart(), diag::err_atomic_op_needs_atomic_int_or_ptr) 1448 << IsC11 << Ptr->getType() << Ptr->getSourceRange(); 1449 return ExprError(); 1450 } 1451 1452 if (!IsC11 && !AtomTy.isTriviallyCopyableType(Context) && 1453 !AtomTy->isScalarType()) { 1454 // For GNU atomics, require a trivially-copyable type. This is not part of 1455 // the GNU atomics specification, but we enforce it for sanity. 1456 Diag(DRE->getLocStart(), diag::err_atomic_op_needs_trivial_copy) 1457 << Ptr->getType() << Ptr->getSourceRange(); 1458 return ExprError(); 1459 } 1460 1461 // FIXME: For any builtin other than a load, the ValType must not be 1462 // const-qualified. 1463 1464 switch (ValType.getObjCLifetime()) { 1465 case Qualifiers::OCL_None: 1466 case Qualifiers::OCL_ExplicitNone: 1467 // okay 1468 break; 1469 1470 case Qualifiers::OCL_Weak: 1471 case Qualifiers::OCL_Strong: 1472 case Qualifiers::OCL_Autoreleasing: 1473 // FIXME: Can this happen? By this point, ValType should be known 1474 // to be trivially copyable. 1475 Diag(DRE->getLocStart(), diag::err_arc_atomic_ownership) 1476 << ValType << Ptr->getSourceRange(); 1477 return ExprError(); 1478 } 1479 1480 QualType ResultType = ValType; 1481 if (Form == Copy || Form == GNUXchg || Form == Init) 1482 ResultType = Context.VoidTy; 1483 else if (Form == C11CmpXchg || Form == GNUCmpXchg) 1484 ResultType = Context.BoolTy; 1485 1486 // The type of a parameter passed 'by value'. In the GNU atomics, such 1487 // arguments are actually passed as pointers. 1488 QualType ByValType = ValType; // 'CP' 1489 if (!IsC11 && !IsN) 1490 ByValType = Ptr->getType(); 1491 1492 // The first argument --- the pointer --- has a fixed type; we 1493 // deduce the types of the rest of the arguments accordingly. Walk 1494 // the remaining arguments, converting them to the deduced value type. 1495 for (unsigned i = 1; i != NumArgs[Form]; ++i) { 1496 QualType Ty; 1497 if (i < NumVals[Form] + 1) { 1498 switch (i) { 1499 case 1: 1500 // The second argument is the non-atomic operand. For arithmetic, this 1501 // is always passed by value, and for a compare_exchange it is always 1502 // passed by address. For the rest, GNU uses by-address and C11 uses 1503 // by-value. 1504 assert(Form != Load); 1505 if (Form == Init || (Form == Arithmetic && ValType->isIntegerType())) 1506 Ty = ValType; 1507 else if (Form == Copy || Form == Xchg) 1508 Ty = ByValType; 1509 else if (Form == Arithmetic) 1510 Ty = Context.getPointerDiffType(); 1511 else 1512 Ty = Context.getPointerType(ValType.getUnqualifiedType()); 1513 break; 1514 case 2: 1515 // The third argument to compare_exchange / GNU exchange is a 1516 // (pointer to a) desired value. 1517 Ty = ByValType; 1518 break; 1519 case 3: 1520 // The fourth argument to GNU compare_exchange is a 'weak' flag. 1521 Ty = Context.BoolTy; 1522 break; 1523 } 1524 } else { 1525 // The order(s) are always converted to int. 1526 Ty = Context.IntTy; 1527 } 1528 1529 InitializedEntity Entity = 1530 InitializedEntity::InitializeParameter(Context, Ty, false); 1531 ExprResult Arg = TheCall->getArg(i); 1532 Arg = PerformCopyInitialization(Entity, SourceLocation(), Arg); 1533 if (Arg.isInvalid()) 1534 return true; 1535 TheCall->setArg(i, Arg.get()); 1536 } 1537 1538 // Permute the arguments into a 'consistent' order. 1539 SmallVector<Expr*, 5> SubExprs; 1540 SubExprs.push_back(Ptr); 1541 switch (Form) { 1542 case Init: 1543 // Note, AtomicExpr::getVal1() has a special case for this atomic. 1544 SubExprs.push_back(TheCall->getArg(1)); // Val1 1545 break; 1546 case Load: 1547 SubExprs.push_back(TheCall->getArg(1)); // Order 1548 break; 1549 case Copy: 1550 case Arithmetic: 1551 case Xchg: 1552 SubExprs.push_back(TheCall->getArg(2)); // Order 1553 SubExprs.push_back(TheCall->getArg(1)); // Val1 1554 break; 1555 case GNUXchg: 1556 // Note, AtomicExpr::getVal2() has a special case for this atomic. 1557 SubExprs.push_back(TheCall->getArg(3)); // Order 1558 SubExprs.push_back(TheCall->getArg(1)); // Val1 1559 SubExprs.push_back(TheCall->getArg(2)); // Val2 1560 break; 1561 case C11CmpXchg: 1562 SubExprs.push_back(TheCall->getArg(3)); // Order 1563 SubExprs.push_back(TheCall->getArg(1)); // Val1 1564 SubExprs.push_back(TheCall->getArg(4)); // OrderFail 1565 SubExprs.push_back(TheCall->getArg(2)); // Val2 1566 break; 1567 case GNUCmpXchg: 1568 SubExprs.push_back(TheCall->getArg(4)); // Order 1569 SubExprs.push_back(TheCall->getArg(1)); // Val1 1570 SubExprs.push_back(TheCall->getArg(5)); // OrderFail 1571 SubExprs.push_back(TheCall->getArg(2)); // Val2 1572 SubExprs.push_back(TheCall->getArg(3)); // Weak 1573 break; 1574 } 1575 1576 if (SubExprs.size() >= 2 && Form != Init) { 1577 llvm::APSInt Result(32); 1578 if (SubExprs[1]->isIntegerConstantExpr(Result, Context) && 1579 !isValidOrderingForOp(Result.getSExtValue(), Op)) 1580 Diag(SubExprs[1]->getLocStart(), 1581 diag::warn_atomic_op_has_invalid_memory_order) 1582 << SubExprs[1]->getSourceRange(); 1583 } 1584 1585 AtomicExpr *AE = new (Context) AtomicExpr(TheCall->getCallee()->getLocStart(), 1586 SubExprs, ResultType, Op, 1587 TheCall->getRParenLoc()); 1588 1589 if ((Op == AtomicExpr::AO__c11_atomic_load || 1590 (Op == AtomicExpr::AO__c11_atomic_store)) && 1591 Context.AtomicUsesUnsupportedLibcall(AE)) 1592 Diag(AE->getLocStart(), diag::err_atomic_load_store_uses_lib) << 1593 ((Op == AtomicExpr::AO__c11_atomic_load) ? 0 : 1); 1594 1595 return AE; 1596 } 1597 1598 1599 /// checkBuiltinArgument - Given a call to a builtin function, perform 1600 /// normal type-checking on the given argument, updating the call in 1601 /// place. This is useful when a builtin function requires custom 1602 /// type-checking for some of its arguments but not necessarily all of 1603 /// them. 1604 /// 1605 /// Returns true on error. 1606 static bool checkBuiltinArgument(Sema &S, CallExpr *E, unsigned ArgIndex) { 1607 FunctionDecl *Fn = E->getDirectCallee(); 1608 assert(Fn && "builtin call without direct callee!"); 1609 1610 ParmVarDecl *Param = Fn->getParamDecl(ArgIndex); 1611 InitializedEntity Entity = 1612 InitializedEntity::InitializeParameter(S.Context, Param); 1613 1614 ExprResult Arg = E->getArg(0); 1615 Arg = S.PerformCopyInitialization(Entity, SourceLocation(), Arg); 1616 if (Arg.isInvalid()) 1617 return true; 1618 1619 E->setArg(ArgIndex, Arg.get()); 1620 return false; 1621 } 1622 1623 /// SemaBuiltinAtomicOverloaded - We have a call to a function like 1624 /// __sync_fetch_and_add, which is an overloaded function based on the pointer 1625 /// type of its first argument. The main ActOnCallExpr routines have already 1626 /// promoted the types of arguments because all of these calls are prototyped as 1627 /// void(...). 1628 /// 1629 /// This function goes through and does final semantic checking for these 1630 /// builtins, 1631 ExprResult 1632 Sema::SemaBuiltinAtomicOverloaded(ExprResult TheCallResult) { 1633 CallExpr *TheCall = (CallExpr *)TheCallResult.get(); 1634 DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts()); 1635 FunctionDecl *FDecl = cast<FunctionDecl>(DRE->getDecl()); 1636 1637 // Ensure that we have at least one argument to do type inference from. 1638 if (TheCall->getNumArgs() < 1) { 1639 Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args_at_least) 1640 << 0 << 1 << TheCall->getNumArgs() 1641 << TheCall->getCallee()->getSourceRange(); 1642 return ExprError(); 1643 } 1644 1645 // Inspect the first argument of the atomic builtin. This should always be 1646 // a pointer type, whose element is an integral scalar or pointer type. 1647 // Because it is a pointer type, we don't have to worry about any implicit 1648 // casts here. 1649 // FIXME: We don't allow floating point scalars as input. 1650 Expr *FirstArg = TheCall->getArg(0); 1651 ExprResult FirstArgResult = DefaultFunctionArrayLvalueConversion(FirstArg); 1652 if (FirstArgResult.isInvalid()) 1653 return ExprError(); 1654 FirstArg = FirstArgResult.get(); 1655 TheCall->setArg(0, FirstArg); 1656 1657 const PointerType *pointerType = FirstArg->getType()->getAs<PointerType>(); 1658 if (!pointerType) { 1659 Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer) 1660 << FirstArg->getType() << FirstArg->getSourceRange(); 1661 return ExprError(); 1662 } 1663 1664 QualType ValType = pointerType->getPointeeType(); 1665 if (!ValType->isIntegerType() && !ValType->isAnyPointerType() && 1666 !ValType->isBlockPointerType()) { 1667 Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer_intptr) 1668 << FirstArg->getType() << FirstArg->getSourceRange(); 1669 return ExprError(); 1670 } 1671 1672 switch (ValType.getObjCLifetime()) { 1673 case Qualifiers::OCL_None: 1674 case Qualifiers::OCL_ExplicitNone: 1675 // okay 1676 break; 1677 1678 case Qualifiers::OCL_Weak: 1679 case Qualifiers::OCL_Strong: 1680 case Qualifiers::OCL_Autoreleasing: 1681 Diag(DRE->getLocStart(), diag::err_arc_atomic_ownership) 1682 << ValType << FirstArg->getSourceRange(); 1683 return ExprError(); 1684 } 1685 1686 // Strip any qualifiers off ValType. 1687 ValType = ValType.getUnqualifiedType(); 1688 1689 // The majority of builtins return a value, but a few have special return 1690 // types, so allow them to override appropriately below. 1691 QualType ResultType = ValType; 1692 1693 // We need to figure out which concrete builtin this maps onto. For example, 1694 // __sync_fetch_and_add with a 2 byte object turns into 1695 // __sync_fetch_and_add_2. 1696 #define BUILTIN_ROW(x) \ 1697 { Builtin::BI##x##_1, Builtin::BI##x##_2, Builtin::BI##x##_4, \ 1698 Builtin::BI##x##_8, Builtin::BI##x##_16 } 1699 1700 static const unsigned BuiltinIndices[][5] = { 1701 BUILTIN_ROW(__sync_fetch_and_add), 1702 BUILTIN_ROW(__sync_fetch_and_sub), 1703 BUILTIN_ROW(__sync_fetch_and_or), 1704 BUILTIN_ROW(__sync_fetch_and_and), 1705 BUILTIN_ROW(__sync_fetch_and_xor), 1706 BUILTIN_ROW(__sync_fetch_and_nand), 1707 1708 BUILTIN_ROW(__sync_add_and_fetch), 1709 BUILTIN_ROW(__sync_sub_and_fetch), 1710 BUILTIN_ROW(__sync_and_and_fetch), 1711 BUILTIN_ROW(__sync_or_and_fetch), 1712 BUILTIN_ROW(__sync_xor_and_fetch), 1713 BUILTIN_ROW(__sync_nand_and_fetch), 1714 1715 BUILTIN_ROW(__sync_val_compare_and_swap), 1716 BUILTIN_ROW(__sync_bool_compare_and_swap), 1717 BUILTIN_ROW(__sync_lock_test_and_set), 1718 BUILTIN_ROW(__sync_lock_release), 1719 BUILTIN_ROW(__sync_swap) 1720 }; 1721 #undef BUILTIN_ROW 1722 1723 // Determine the index of the size. 1724 unsigned SizeIndex; 1725 switch (Context.getTypeSizeInChars(ValType).getQuantity()) { 1726 case 1: SizeIndex = 0; break; 1727 case 2: SizeIndex = 1; break; 1728 case 4: SizeIndex = 2; break; 1729 case 8: SizeIndex = 3; break; 1730 case 16: SizeIndex = 4; break; 1731 default: 1732 Diag(DRE->getLocStart(), diag::err_atomic_builtin_pointer_size) 1733 << FirstArg->getType() << FirstArg->getSourceRange(); 1734 return ExprError(); 1735 } 1736 1737 // Each of these builtins has one pointer argument, followed by some number of 1738 // values (0, 1 or 2) followed by a potentially empty varags list of stuff 1739 // that we ignore. Find out which row of BuiltinIndices to read from as well 1740 // as the number of fixed args. 1741 unsigned BuiltinID = FDecl->getBuiltinID(); 1742 unsigned BuiltinIndex, NumFixed = 1; 1743 bool WarnAboutSemanticsChange = false; 1744 switch (BuiltinID) { 1745 default: llvm_unreachable("Unknown overloaded atomic builtin!"); 1746 case Builtin::BI__sync_fetch_and_add: 1747 case Builtin::BI__sync_fetch_and_add_1: 1748 case Builtin::BI__sync_fetch_and_add_2: 1749 case Builtin::BI__sync_fetch_and_add_4: 1750 case Builtin::BI__sync_fetch_and_add_8: 1751 case Builtin::BI__sync_fetch_and_add_16: 1752 BuiltinIndex = 0; 1753 break; 1754 1755 case Builtin::BI__sync_fetch_and_sub: 1756 case Builtin::BI__sync_fetch_and_sub_1: 1757 case Builtin::BI__sync_fetch_and_sub_2: 1758 case Builtin::BI__sync_fetch_and_sub_4: 1759 case Builtin::BI__sync_fetch_and_sub_8: 1760 case Builtin::BI__sync_fetch_and_sub_16: 1761 BuiltinIndex = 1; 1762 break; 1763 1764 case Builtin::BI__sync_fetch_and_or: 1765 case Builtin::BI__sync_fetch_and_or_1: 1766 case Builtin::BI__sync_fetch_and_or_2: 1767 case Builtin::BI__sync_fetch_and_or_4: 1768 case Builtin::BI__sync_fetch_and_or_8: 1769 case Builtin::BI__sync_fetch_and_or_16: 1770 BuiltinIndex = 2; 1771 break; 1772 1773 case Builtin::BI__sync_fetch_and_and: 1774 case Builtin::BI__sync_fetch_and_and_1: 1775 case Builtin::BI__sync_fetch_and_and_2: 1776 case Builtin::BI__sync_fetch_and_and_4: 1777 case Builtin::BI__sync_fetch_and_and_8: 1778 case Builtin::BI__sync_fetch_and_and_16: 1779 BuiltinIndex = 3; 1780 break; 1781 1782 case Builtin::BI__sync_fetch_and_xor: 1783 case Builtin::BI__sync_fetch_and_xor_1: 1784 case Builtin::BI__sync_fetch_and_xor_2: 1785 case Builtin::BI__sync_fetch_and_xor_4: 1786 case Builtin::BI__sync_fetch_and_xor_8: 1787 case Builtin::BI__sync_fetch_and_xor_16: 1788 BuiltinIndex = 4; 1789 break; 1790 1791 case Builtin::BI__sync_fetch_and_nand: 1792 case Builtin::BI__sync_fetch_and_nand_1: 1793 case Builtin::BI__sync_fetch_and_nand_2: 1794 case Builtin::BI__sync_fetch_and_nand_4: 1795 case Builtin::BI__sync_fetch_and_nand_8: 1796 case Builtin::BI__sync_fetch_and_nand_16: 1797 BuiltinIndex = 5; 1798 WarnAboutSemanticsChange = true; 1799 break; 1800 1801 case Builtin::BI__sync_add_and_fetch: 1802 case Builtin::BI__sync_add_and_fetch_1: 1803 case Builtin::BI__sync_add_and_fetch_2: 1804 case Builtin::BI__sync_add_and_fetch_4: 1805 case Builtin::BI__sync_add_and_fetch_8: 1806 case Builtin::BI__sync_add_and_fetch_16: 1807 BuiltinIndex = 6; 1808 break; 1809 1810 case Builtin::BI__sync_sub_and_fetch: 1811 case Builtin::BI__sync_sub_and_fetch_1: 1812 case Builtin::BI__sync_sub_and_fetch_2: 1813 case Builtin::BI__sync_sub_and_fetch_4: 1814 case Builtin::BI__sync_sub_and_fetch_8: 1815 case Builtin::BI__sync_sub_and_fetch_16: 1816 BuiltinIndex = 7; 1817 break; 1818 1819 case Builtin::BI__sync_and_and_fetch: 1820 case Builtin::BI__sync_and_and_fetch_1: 1821 case Builtin::BI__sync_and_and_fetch_2: 1822 case Builtin::BI__sync_and_and_fetch_4: 1823 case Builtin::BI__sync_and_and_fetch_8: 1824 case Builtin::BI__sync_and_and_fetch_16: 1825 BuiltinIndex = 8; 1826 break; 1827 1828 case Builtin::BI__sync_or_and_fetch: 1829 case Builtin::BI__sync_or_and_fetch_1: 1830 case Builtin::BI__sync_or_and_fetch_2: 1831 case Builtin::BI__sync_or_and_fetch_4: 1832 case Builtin::BI__sync_or_and_fetch_8: 1833 case Builtin::BI__sync_or_and_fetch_16: 1834 BuiltinIndex = 9; 1835 break; 1836 1837 case Builtin::BI__sync_xor_and_fetch: 1838 case Builtin::BI__sync_xor_and_fetch_1: 1839 case Builtin::BI__sync_xor_and_fetch_2: 1840 case Builtin::BI__sync_xor_and_fetch_4: 1841 case Builtin::BI__sync_xor_and_fetch_8: 1842 case Builtin::BI__sync_xor_and_fetch_16: 1843 BuiltinIndex = 10; 1844 break; 1845 1846 case Builtin::BI__sync_nand_and_fetch: 1847 case Builtin::BI__sync_nand_and_fetch_1: 1848 case Builtin::BI__sync_nand_and_fetch_2: 1849 case Builtin::BI__sync_nand_and_fetch_4: 1850 case Builtin::BI__sync_nand_and_fetch_8: 1851 case Builtin::BI__sync_nand_and_fetch_16: 1852 BuiltinIndex = 11; 1853 WarnAboutSemanticsChange = true; 1854 break; 1855 1856 case Builtin::BI__sync_val_compare_and_swap: 1857 case Builtin::BI__sync_val_compare_and_swap_1: 1858 case Builtin::BI__sync_val_compare_and_swap_2: 1859 case Builtin::BI__sync_val_compare_and_swap_4: 1860 case Builtin::BI__sync_val_compare_and_swap_8: 1861 case Builtin::BI__sync_val_compare_and_swap_16: 1862 BuiltinIndex = 12; 1863 NumFixed = 2; 1864 break; 1865 1866 case Builtin::BI__sync_bool_compare_and_swap: 1867 case Builtin::BI__sync_bool_compare_and_swap_1: 1868 case Builtin::BI__sync_bool_compare_and_swap_2: 1869 case Builtin::BI__sync_bool_compare_and_swap_4: 1870 case Builtin::BI__sync_bool_compare_and_swap_8: 1871 case Builtin::BI__sync_bool_compare_and_swap_16: 1872 BuiltinIndex = 13; 1873 NumFixed = 2; 1874 ResultType = Context.BoolTy; 1875 break; 1876 1877 case Builtin::BI__sync_lock_test_and_set: 1878 case Builtin::BI__sync_lock_test_and_set_1: 1879 case Builtin::BI__sync_lock_test_and_set_2: 1880 case Builtin::BI__sync_lock_test_and_set_4: 1881 case Builtin::BI__sync_lock_test_and_set_8: 1882 case Builtin::BI__sync_lock_test_and_set_16: 1883 BuiltinIndex = 14; 1884 break; 1885 1886 case Builtin::BI__sync_lock_release: 1887 case Builtin::BI__sync_lock_release_1: 1888 case Builtin::BI__sync_lock_release_2: 1889 case Builtin::BI__sync_lock_release_4: 1890 case Builtin::BI__sync_lock_release_8: 1891 case Builtin::BI__sync_lock_release_16: 1892 BuiltinIndex = 15; 1893 NumFixed = 0; 1894 ResultType = Context.VoidTy; 1895 break; 1896 1897 case Builtin::BI__sync_swap: 1898 case Builtin::BI__sync_swap_1: 1899 case Builtin::BI__sync_swap_2: 1900 case Builtin::BI__sync_swap_4: 1901 case Builtin::BI__sync_swap_8: 1902 case Builtin::BI__sync_swap_16: 1903 BuiltinIndex = 16; 1904 break; 1905 } 1906 1907 // Now that we know how many fixed arguments we expect, first check that we 1908 // have at least that many. 1909 if (TheCall->getNumArgs() < 1+NumFixed) { 1910 Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args_at_least) 1911 << 0 << 1+NumFixed << TheCall->getNumArgs() 1912 << TheCall->getCallee()->getSourceRange(); 1913 return ExprError(); 1914 } 1915 1916 if (WarnAboutSemanticsChange) { 1917 Diag(TheCall->getLocEnd(), diag::warn_sync_fetch_and_nand_semantics_change) 1918 << TheCall->getCallee()->getSourceRange(); 1919 } 1920 1921 // Get the decl for the concrete builtin from this, we can tell what the 1922 // concrete integer type we should convert to is. 1923 unsigned NewBuiltinID = BuiltinIndices[BuiltinIndex][SizeIndex]; 1924 const char *NewBuiltinName = Context.BuiltinInfo.GetName(NewBuiltinID); 1925 FunctionDecl *NewBuiltinDecl; 1926 if (NewBuiltinID == BuiltinID) 1927 NewBuiltinDecl = FDecl; 1928 else { 1929 // Perform builtin lookup to avoid redeclaring it. 1930 DeclarationName DN(&Context.Idents.get(NewBuiltinName)); 1931 LookupResult Res(*this, DN, DRE->getLocStart(), LookupOrdinaryName); 1932 LookupName(Res, TUScope, /*AllowBuiltinCreation=*/true); 1933 assert(Res.getFoundDecl()); 1934 NewBuiltinDecl = dyn_cast<FunctionDecl>(Res.getFoundDecl()); 1935 if (!NewBuiltinDecl) 1936 return ExprError(); 1937 } 1938 1939 // The first argument --- the pointer --- has a fixed type; we 1940 // deduce the types of the rest of the arguments accordingly. Walk 1941 // the remaining arguments, converting them to the deduced value type. 1942 for (unsigned i = 0; i != NumFixed; ++i) { 1943 ExprResult Arg = TheCall->getArg(i+1); 1944 1945 // GCC does an implicit conversion to the pointer or integer ValType. This 1946 // can fail in some cases (1i -> int**), check for this error case now. 1947 // Initialize the argument. 1948 InitializedEntity Entity = InitializedEntity::InitializeParameter(Context, 1949 ValType, /*consume*/ false); 1950 Arg = PerformCopyInitialization(Entity, SourceLocation(), Arg); 1951 if (Arg.isInvalid()) 1952 return ExprError(); 1953 1954 // Okay, we have something that *can* be converted to the right type. Check 1955 // to see if there is a potentially weird extension going on here. This can 1956 // happen when you do an atomic operation on something like an char* and 1957 // pass in 42. The 42 gets converted to char. This is even more strange 1958 // for things like 45.123 -> char, etc. 1959 // FIXME: Do this check. 1960 TheCall->setArg(i+1, Arg.get()); 1961 } 1962 1963 ASTContext& Context = this->getASTContext(); 1964 1965 // Create a new DeclRefExpr to refer to the new decl. 1966 DeclRefExpr* NewDRE = DeclRefExpr::Create( 1967 Context, 1968 DRE->getQualifierLoc(), 1969 SourceLocation(), 1970 NewBuiltinDecl, 1971 /*enclosing*/ false, 1972 DRE->getLocation(), 1973 Context.BuiltinFnTy, 1974 DRE->getValueKind()); 1975 1976 // Set the callee in the CallExpr. 1977 // FIXME: This loses syntactic information. 1978 QualType CalleePtrTy = Context.getPointerType(NewBuiltinDecl->getType()); 1979 ExprResult PromotedCall = ImpCastExprToType(NewDRE, CalleePtrTy, 1980 CK_BuiltinFnToFnPtr); 1981 TheCall->setCallee(PromotedCall.get()); 1982 1983 // Change the result type of the call to match the original value type. This 1984 // is arbitrary, but the codegen for these builtins ins design to handle it 1985 // gracefully. 1986 TheCall->setType(ResultType); 1987 1988 return TheCallResult; 1989 } 1990 1991 /// CheckObjCString - Checks that the argument to the builtin 1992 /// CFString constructor is correct 1993 /// Note: It might also make sense to do the UTF-16 conversion here (would 1994 /// simplify the backend). 1995 bool Sema::CheckObjCString(Expr *Arg) { 1996 Arg = Arg->IgnoreParenCasts(); 1997 StringLiteral *Literal = dyn_cast<StringLiteral>(Arg); 1998 1999 if (!Literal || !Literal->isAscii()) { 2000 Diag(Arg->getLocStart(), diag::err_cfstring_literal_not_string_constant) 2001 << Arg->getSourceRange(); 2002 return true; 2003 } 2004 2005 if (Literal->containsNonAsciiOrNull()) { 2006 StringRef String = Literal->getString(); 2007 unsigned NumBytes = String.size(); 2008 SmallVector<UTF16, 128> ToBuf(NumBytes); 2009 const UTF8 *FromPtr = (const UTF8 *)String.data(); 2010 UTF16 *ToPtr = &ToBuf[0]; 2011 2012 ConversionResult Result = ConvertUTF8toUTF16(&FromPtr, FromPtr + NumBytes, 2013 &ToPtr, ToPtr + NumBytes, 2014 strictConversion); 2015 // Check for conversion failure. 2016 if (Result != conversionOK) 2017 Diag(Arg->getLocStart(), 2018 diag::warn_cfstring_truncated) << Arg->getSourceRange(); 2019 } 2020 return false; 2021 } 2022 2023 /// SemaBuiltinVAStart - Check the arguments to __builtin_va_start for validity. 2024 /// Emit an error and return true on failure, return false on success. 2025 bool Sema::SemaBuiltinVAStart(CallExpr *TheCall) { 2026 Expr *Fn = TheCall->getCallee(); 2027 if (TheCall->getNumArgs() > 2) { 2028 Diag(TheCall->getArg(2)->getLocStart(), 2029 diag::err_typecheck_call_too_many_args) 2030 << 0 /*function call*/ << 2 << TheCall->getNumArgs() 2031 << Fn->getSourceRange() 2032 << SourceRange(TheCall->getArg(2)->getLocStart(), 2033 (*(TheCall->arg_end()-1))->getLocEnd()); 2034 return true; 2035 } 2036 2037 if (TheCall->getNumArgs() < 2) { 2038 return Diag(TheCall->getLocEnd(), 2039 diag::err_typecheck_call_too_few_args_at_least) 2040 << 0 /*function call*/ << 2 << TheCall->getNumArgs(); 2041 } 2042 2043 // Type-check the first argument normally. 2044 if (checkBuiltinArgument(*this, TheCall, 0)) 2045 return true; 2046 2047 // Determine whether the current function is variadic or not. 2048 BlockScopeInfo *CurBlock = getCurBlock(); 2049 bool isVariadic; 2050 if (CurBlock) 2051 isVariadic = CurBlock->TheDecl->isVariadic(); 2052 else if (FunctionDecl *FD = getCurFunctionDecl()) 2053 isVariadic = FD->isVariadic(); 2054 else 2055 isVariadic = getCurMethodDecl()->isVariadic(); 2056 2057 if (!isVariadic) { 2058 Diag(Fn->getLocStart(), diag::err_va_start_used_in_non_variadic_function); 2059 return true; 2060 } 2061 2062 // Verify that the second argument to the builtin is the last argument of the 2063 // current function or method. 2064 bool SecondArgIsLastNamedArgument = false; 2065 const Expr *Arg = TheCall->getArg(1)->IgnoreParenCasts(); 2066 2067 // These are valid if SecondArgIsLastNamedArgument is false after the next 2068 // block. 2069 QualType Type; 2070 SourceLocation ParamLoc; 2071 2072 if (const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(Arg)) { 2073 if (const ParmVarDecl *PV = dyn_cast<ParmVarDecl>(DR->getDecl())) { 2074 // FIXME: This isn't correct for methods (results in bogus warning). 2075 // Get the last formal in the current function. 2076 const ParmVarDecl *LastArg; 2077 if (CurBlock) 2078 LastArg = *(CurBlock->TheDecl->param_end()-1); 2079 else if (FunctionDecl *FD = getCurFunctionDecl()) 2080 LastArg = *(FD->param_end()-1); 2081 else 2082 LastArg = *(getCurMethodDecl()->param_end()-1); 2083 SecondArgIsLastNamedArgument = PV == LastArg; 2084 2085 Type = PV->getType(); 2086 ParamLoc = PV->getLocation(); 2087 } 2088 } 2089 2090 if (!SecondArgIsLastNamedArgument) 2091 Diag(TheCall->getArg(1)->getLocStart(), 2092 diag::warn_second_parameter_of_va_start_not_last_named_argument); 2093 else if (Type->isReferenceType()) { 2094 Diag(Arg->getLocStart(), 2095 diag::warn_va_start_of_reference_type_is_undefined); 2096 Diag(ParamLoc, diag::note_parameter_type) << Type; 2097 } 2098 2099 TheCall->setType(Context.VoidTy); 2100 return false; 2101 } 2102 2103 bool Sema::SemaBuiltinVAStartARM(CallExpr *Call) { 2104 // void __va_start(va_list *ap, const char *named_addr, size_t slot_size, 2105 // const char *named_addr); 2106 2107 Expr *Func = Call->getCallee(); 2108 2109 if (Call->getNumArgs() < 3) 2110 return Diag(Call->getLocEnd(), 2111 diag::err_typecheck_call_too_few_args_at_least) 2112 << 0 /*function call*/ << 3 << Call->getNumArgs(); 2113 2114 // Determine whether the current function is variadic or not. 2115 bool IsVariadic; 2116 if (BlockScopeInfo *CurBlock = getCurBlock()) 2117 IsVariadic = CurBlock->TheDecl->isVariadic(); 2118 else if (FunctionDecl *FD = getCurFunctionDecl()) 2119 IsVariadic = FD->isVariadic(); 2120 else if (ObjCMethodDecl *MD = getCurMethodDecl()) 2121 IsVariadic = MD->isVariadic(); 2122 else 2123 llvm_unreachable("unexpected statement type"); 2124 2125 if (!IsVariadic) { 2126 Diag(Func->getLocStart(), diag::err_va_start_used_in_non_variadic_function); 2127 return true; 2128 } 2129 2130 // Type-check the first argument normally. 2131 if (checkBuiltinArgument(*this, Call, 0)) 2132 return true; 2133 2134 static const struct { 2135 unsigned ArgNo; 2136 QualType Type; 2137 } ArgumentTypes[] = { 2138 { 1, Context.getPointerType(Context.CharTy.withConst()) }, 2139 { 2, Context.getSizeType() }, 2140 }; 2141 2142 for (const auto &AT : ArgumentTypes) { 2143 const Expr *Arg = Call->getArg(AT.ArgNo)->IgnoreParens(); 2144 if (Arg->getType().getCanonicalType() == AT.Type.getCanonicalType()) 2145 continue; 2146 Diag(Arg->getLocStart(), diag::err_typecheck_convert_incompatible) 2147 << Arg->getType() << AT.Type << 1 /* different class */ 2148 << 0 /* qualifier difference */ << 3 /* parameter mismatch */ 2149 << AT.ArgNo + 1 << Arg->getType() << AT.Type; 2150 } 2151 2152 return false; 2153 } 2154 2155 /// SemaBuiltinUnorderedCompare - Handle functions like __builtin_isgreater and 2156 /// friends. This is declared to take (...), so we have to check everything. 2157 bool Sema::SemaBuiltinUnorderedCompare(CallExpr *TheCall) { 2158 if (TheCall->getNumArgs() < 2) 2159 return Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args) 2160 << 0 << 2 << TheCall->getNumArgs()/*function call*/; 2161 if (TheCall->getNumArgs() > 2) 2162 return Diag(TheCall->getArg(2)->getLocStart(), 2163 diag::err_typecheck_call_too_many_args) 2164 << 0 /*function call*/ << 2 << TheCall->getNumArgs() 2165 << SourceRange(TheCall->getArg(2)->getLocStart(), 2166 (*(TheCall->arg_end()-1))->getLocEnd()); 2167 2168 ExprResult OrigArg0 = TheCall->getArg(0); 2169 ExprResult OrigArg1 = TheCall->getArg(1); 2170 2171 // Do standard promotions between the two arguments, returning their common 2172 // type. 2173 QualType Res = UsualArithmeticConversions(OrigArg0, OrigArg1, false); 2174 if (OrigArg0.isInvalid() || OrigArg1.isInvalid()) 2175 return true; 2176 2177 // Make sure any conversions are pushed back into the call; this is 2178 // type safe since unordered compare builtins are declared as "_Bool 2179 // foo(...)". 2180 TheCall->setArg(0, OrigArg0.get()); 2181 TheCall->setArg(1, OrigArg1.get()); 2182 2183 if (OrigArg0.get()->isTypeDependent() || OrigArg1.get()->isTypeDependent()) 2184 return false; 2185 2186 // If the common type isn't a real floating type, then the arguments were 2187 // invalid for this operation. 2188 if (Res.isNull() || !Res->isRealFloatingType()) 2189 return Diag(OrigArg0.get()->getLocStart(), 2190 diag::err_typecheck_call_invalid_ordered_compare) 2191 << OrigArg0.get()->getType() << OrigArg1.get()->getType() 2192 << SourceRange(OrigArg0.get()->getLocStart(), OrigArg1.get()->getLocEnd()); 2193 2194 return false; 2195 } 2196 2197 /// SemaBuiltinSemaBuiltinFPClassification - Handle functions like 2198 /// __builtin_isnan and friends. This is declared to take (...), so we have 2199 /// to check everything. We expect the last argument to be a floating point 2200 /// value. 2201 bool Sema::SemaBuiltinFPClassification(CallExpr *TheCall, unsigned NumArgs) { 2202 if (TheCall->getNumArgs() < NumArgs) 2203 return Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args) 2204 << 0 << NumArgs << TheCall->getNumArgs()/*function call*/; 2205 if (TheCall->getNumArgs() > NumArgs) 2206 return Diag(TheCall->getArg(NumArgs)->getLocStart(), 2207 diag::err_typecheck_call_too_many_args) 2208 << 0 /*function call*/ << NumArgs << TheCall->getNumArgs() 2209 << SourceRange(TheCall->getArg(NumArgs)->getLocStart(), 2210 (*(TheCall->arg_end()-1))->getLocEnd()); 2211 2212 Expr *OrigArg = TheCall->getArg(NumArgs-1); 2213 2214 if (OrigArg->isTypeDependent()) 2215 return false; 2216 2217 // This operation requires a non-_Complex floating-point number. 2218 if (!OrigArg->getType()->isRealFloatingType()) 2219 return Diag(OrigArg->getLocStart(), 2220 diag::err_typecheck_call_invalid_unary_fp) 2221 << OrigArg->getType() << OrigArg->getSourceRange(); 2222 2223 // If this is an implicit conversion from float -> double, remove it. 2224 if (ImplicitCastExpr *Cast = dyn_cast<ImplicitCastExpr>(OrigArg)) { 2225 Expr *CastArg = Cast->getSubExpr(); 2226 if (CastArg->getType()->isSpecificBuiltinType(BuiltinType::Float)) { 2227 assert(Cast->getType()->isSpecificBuiltinType(BuiltinType::Double) && 2228 "promotion from float to double is the only expected cast here"); 2229 Cast->setSubExpr(nullptr); 2230 TheCall->setArg(NumArgs-1, CastArg); 2231 } 2232 } 2233 2234 return false; 2235 } 2236 2237 /// SemaBuiltinShuffleVector - Handle __builtin_shufflevector. 2238 // This is declared to take (...), so we have to check everything. 2239 ExprResult Sema::SemaBuiltinShuffleVector(CallExpr *TheCall) { 2240 if (TheCall->getNumArgs() < 2) 2241 return ExprError(Diag(TheCall->getLocEnd(), 2242 diag::err_typecheck_call_too_few_args_at_least) 2243 << 0 /*function call*/ << 2 << TheCall->getNumArgs() 2244 << TheCall->getSourceRange()); 2245 2246 // Determine which of the following types of shufflevector we're checking: 2247 // 1) unary, vector mask: (lhs, mask) 2248 // 2) binary, vector mask: (lhs, rhs, mask) 2249 // 3) binary, scalar mask: (lhs, rhs, index, ..., index) 2250 QualType resType = TheCall->getArg(0)->getType(); 2251 unsigned numElements = 0; 2252 2253 if (!TheCall->getArg(0)->isTypeDependent() && 2254 !TheCall->getArg(1)->isTypeDependent()) { 2255 QualType LHSType = TheCall->getArg(0)->getType(); 2256 QualType RHSType = TheCall->getArg(1)->getType(); 2257 2258 if (!LHSType->isVectorType() || !RHSType->isVectorType()) 2259 return ExprError(Diag(TheCall->getLocStart(), 2260 diag::err_shufflevector_non_vector) 2261 << SourceRange(TheCall->getArg(0)->getLocStart(), 2262 TheCall->getArg(1)->getLocEnd())); 2263 2264 numElements = LHSType->getAs<VectorType>()->getNumElements(); 2265 unsigned numResElements = TheCall->getNumArgs() - 2; 2266 2267 // Check to see if we have a call with 2 vector arguments, the unary shuffle 2268 // with mask. If so, verify that RHS is an integer vector type with the 2269 // same number of elts as lhs. 2270 if (TheCall->getNumArgs() == 2) { 2271 if (!RHSType->hasIntegerRepresentation() || 2272 RHSType->getAs<VectorType>()->getNumElements() != numElements) 2273 return ExprError(Diag(TheCall->getLocStart(), 2274 diag::err_shufflevector_incompatible_vector) 2275 << SourceRange(TheCall->getArg(1)->getLocStart(), 2276 TheCall->getArg(1)->getLocEnd())); 2277 } else if (!Context.hasSameUnqualifiedType(LHSType, RHSType)) { 2278 return ExprError(Diag(TheCall->getLocStart(), 2279 diag::err_shufflevector_incompatible_vector) 2280 << SourceRange(TheCall->getArg(0)->getLocStart(), 2281 TheCall->getArg(1)->getLocEnd())); 2282 } else if (numElements != numResElements) { 2283 QualType eltType = LHSType->getAs<VectorType>()->getElementType(); 2284 resType = Context.getVectorType(eltType, numResElements, 2285 VectorType::GenericVector); 2286 } 2287 } 2288 2289 for (unsigned i = 2; i < TheCall->getNumArgs(); i++) { 2290 if (TheCall->getArg(i)->isTypeDependent() || 2291 TheCall->getArg(i)->isValueDependent()) 2292 continue; 2293 2294 llvm::APSInt Result(32); 2295 if (!TheCall->getArg(i)->isIntegerConstantExpr(Result, Context)) 2296 return ExprError(Diag(TheCall->getLocStart(), 2297 diag::err_shufflevector_nonconstant_argument) 2298 << TheCall->getArg(i)->getSourceRange()); 2299 2300 // Allow -1 which will be translated to undef in the IR. 2301 if (Result.isSigned() && Result.isAllOnesValue()) 2302 continue; 2303 2304 if (Result.getActiveBits() > 64 || Result.getZExtValue() >= numElements*2) 2305 return ExprError(Diag(TheCall->getLocStart(), 2306 diag::err_shufflevector_argument_too_large) 2307 << TheCall->getArg(i)->getSourceRange()); 2308 } 2309 2310 SmallVector<Expr*, 32> exprs; 2311 2312 for (unsigned i = 0, e = TheCall->getNumArgs(); i != e; i++) { 2313 exprs.push_back(TheCall->getArg(i)); 2314 TheCall->setArg(i, nullptr); 2315 } 2316 2317 return new (Context) ShuffleVectorExpr(Context, exprs, resType, 2318 TheCall->getCallee()->getLocStart(), 2319 TheCall->getRParenLoc()); 2320 } 2321 2322 /// SemaConvertVectorExpr - Handle __builtin_convertvector 2323 ExprResult Sema::SemaConvertVectorExpr(Expr *E, TypeSourceInfo *TInfo, 2324 SourceLocation BuiltinLoc, 2325 SourceLocation RParenLoc) { 2326 ExprValueKind VK = VK_RValue; 2327 ExprObjectKind OK = OK_Ordinary; 2328 QualType DstTy = TInfo->getType(); 2329 QualType SrcTy = E->getType(); 2330 2331 if (!SrcTy->isVectorType() && !SrcTy->isDependentType()) 2332 return ExprError(Diag(BuiltinLoc, 2333 diag::err_convertvector_non_vector) 2334 << E->getSourceRange()); 2335 if (!DstTy->isVectorType() && !DstTy->isDependentType()) 2336 return ExprError(Diag(BuiltinLoc, 2337 diag::err_convertvector_non_vector_type)); 2338 2339 if (!SrcTy->isDependentType() && !DstTy->isDependentType()) { 2340 unsigned SrcElts = SrcTy->getAs<VectorType>()->getNumElements(); 2341 unsigned DstElts = DstTy->getAs<VectorType>()->getNumElements(); 2342 if (SrcElts != DstElts) 2343 return ExprError(Diag(BuiltinLoc, 2344 diag::err_convertvector_incompatible_vector) 2345 << E->getSourceRange()); 2346 } 2347 2348 return new (Context) 2349 ConvertVectorExpr(E, TInfo, DstTy, VK, OK, BuiltinLoc, RParenLoc); 2350 } 2351 2352 /// SemaBuiltinPrefetch - Handle __builtin_prefetch. 2353 // This is declared to take (const void*, ...) and can take two 2354 // optional constant int args. 2355 bool Sema::SemaBuiltinPrefetch(CallExpr *TheCall) { 2356 unsigned NumArgs = TheCall->getNumArgs(); 2357 2358 if (NumArgs > 3) 2359 return Diag(TheCall->getLocEnd(), 2360 diag::err_typecheck_call_too_many_args_at_most) 2361 << 0 /*function call*/ << 3 << NumArgs 2362 << TheCall->getSourceRange(); 2363 2364 // Argument 0 is checked for us and the remaining arguments must be 2365 // constant integers. 2366 for (unsigned i = 1; i != NumArgs; ++i) 2367 if (SemaBuiltinConstantArgRange(TheCall, i, 0, i == 1 ? 1 : 3)) 2368 return true; 2369 2370 return false; 2371 } 2372 2373 /// SemaBuiltinAssume - Handle __assume (MS Extension). 2374 // __assume does not evaluate its arguments, and should warn if its argument 2375 // has side effects. 2376 bool Sema::SemaBuiltinAssume(CallExpr *TheCall) { 2377 Expr *Arg = TheCall->getArg(0); 2378 if (Arg->isInstantiationDependent()) return false; 2379 2380 if (Arg->HasSideEffects(Context)) 2381 return Diag(Arg->getLocStart(), diag::warn_assume_side_effects) 2382 << Arg->getSourceRange() 2383 << cast<FunctionDecl>(TheCall->getCalleeDecl())->getIdentifier(); 2384 2385 return false; 2386 } 2387 2388 /// Handle __builtin_assume_aligned. This is declared 2389 /// as (const void*, size_t, ...) and can take one optional constant int arg. 2390 bool Sema::SemaBuiltinAssumeAligned(CallExpr *TheCall) { 2391 unsigned NumArgs = TheCall->getNumArgs(); 2392 2393 if (NumArgs > 3) 2394 return Diag(TheCall->getLocEnd(), 2395 diag::err_typecheck_call_too_many_args_at_most) 2396 << 0 /*function call*/ << 3 << NumArgs 2397 << TheCall->getSourceRange(); 2398 2399 // The alignment must be a constant integer. 2400 Expr *Arg = TheCall->getArg(1); 2401 2402 // We can't check the value of a dependent argument. 2403 if (!Arg->isTypeDependent() && !Arg->isValueDependent()) { 2404 llvm::APSInt Result; 2405 if (SemaBuiltinConstantArg(TheCall, 1, Result)) 2406 return true; 2407 2408 if (!Result.isPowerOf2()) 2409 return Diag(TheCall->getLocStart(), 2410 diag::err_alignment_not_power_of_two) 2411 << Arg->getSourceRange(); 2412 } 2413 2414 if (NumArgs > 2) { 2415 ExprResult Arg(TheCall->getArg(2)); 2416 InitializedEntity Entity = InitializedEntity::InitializeParameter(Context, 2417 Context.getSizeType(), false); 2418 Arg = PerformCopyInitialization(Entity, SourceLocation(), Arg); 2419 if (Arg.isInvalid()) return true; 2420 TheCall->setArg(2, Arg.get()); 2421 } 2422 2423 return false; 2424 } 2425 2426 /// SemaBuiltinConstantArg - Handle a check if argument ArgNum of CallExpr 2427 /// TheCall is a constant expression. 2428 bool Sema::SemaBuiltinConstantArg(CallExpr *TheCall, int ArgNum, 2429 llvm::APSInt &Result) { 2430 Expr *Arg = TheCall->getArg(ArgNum); 2431 DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts()); 2432 FunctionDecl *FDecl = cast<FunctionDecl>(DRE->getDecl()); 2433 2434 if (Arg->isTypeDependent() || Arg->isValueDependent()) return false; 2435 2436 if (!Arg->isIntegerConstantExpr(Result, Context)) 2437 return Diag(TheCall->getLocStart(), diag::err_constant_integer_arg_type) 2438 << FDecl->getDeclName() << Arg->getSourceRange(); 2439 2440 return false; 2441 } 2442 2443 /// SemaBuiltinConstantArgRange - Handle a check if argument ArgNum of CallExpr 2444 /// TheCall is a constant expression in the range [Low, High]. 2445 bool Sema::SemaBuiltinConstantArgRange(CallExpr *TheCall, int ArgNum, 2446 int Low, int High) { 2447 llvm::APSInt Result; 2448 2449 // We can't check the value of a dependent argument. 2450 Expr *Arg = TheCall->getArg(ArgNum); 2451 if (Arg->isTypeDependent() || Arg->isValueDependent()) 2452 return false; 2453 2454 // Check constant-ness first. 2455 if (SemaBuiltinConstantArg(TheCall, ArgNum, Result)) 2456 return true; 2457 2458 if (Result.getSExtValue() < Low || Result.getSExtValue() > High) 2459 return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range) 2460 << Low << High << Arg->getSourceRange(); 2461 2462 return false; 2463 } 2464 2465 /// SemaBuiltinLongjmp - Handle __builtin_longjmp(void *env[5], int val). 2466 /// This checks that val is a constant 1. 2467 bool Sema::SemaBuiltinLongjmp(CallExpr *TheCall) { 2468 Expr *Arg = TheCall->getArg(1); 2469 llvm::APSInt Result; 2470 2471 // TODO: This is less than ideal. Overload this to take a value. 2472 if (SemaBuiltinConstantArg(TheCall, 1, Result)) 2473 return true; 2474 2475 if (Result != 1) 2476 return Diag(TheCall->getLocStart(), diag::err_builtin_longjmp_invalid_val) 2477 << SourceRange(Arg->getLocStart(), Arg->getLocEnd()); 2478 2479 return false; 2480 } 2481 2482 namespace { 2483 enum StringLiteralCheckType { 2484 SLCT_NotALiteral, 2485 SLCT_UncheckedLiteral, 2486 SLCT_CheckedLiteral 2487 }; 2488 } 2489 2490 // Determine if an expression is a string literal or constant string. 2491 // If this function returns false on the arguments to a function expecting a 2492 // format string, we will usually need to emit a warning. 2493 // True string literals are then checked by CheckFormatString. 2494 static StringLiteralCheckType 2495 checkFormatStringExpr(Sema &S, const Expr *E, ArrayRef<const Expr *> Args, 2496 bool HasVAListArg, unsigned format_idx, 2497 unsigned firstDataArg, Sema::FormatStringType Type, 2498 Sema::VariadicCallType CallType, bool InFunctionCall, 2499 llvm::SmallBitVector &CheckedVarArgs) { 2500 tryAgain: 2501 if (E->isTypeDependent() || E->isValueDependent()) 2502 return SLCT_NotALiteral; 2503 2504 E = E->IgnoreParenCasts(); 2505 2506 if (E->isNullPointerConstant(S.Context, Expr::NPC_ValueDependentIsNotNull)) 2507 // Technically -Wformat-nonliteral does not warn about this case. 2508 // The behavior of printf and friends in this case is implementation 2509 // dependent. Ideally if the format string cannot be null then 2510 // it should have a 'nonnull' attribute in the function prototype. 2511 return SLCT_UncheckedLiteral; 2512 2513 switch (E->getStmtClass()) { 2514 case Stmt::BinaryConditionalOperatorClass: 2515 case Stmt::ConditionalOperatorClass: { 2516 // The expression is a literal if both sub-expressions were, and it was 2517 // completely checked only if both sub-expressions were checked. 2518 const AbstractConditionalOperator *C = 2519 cast<AbstractConditionalOperator>(E); 2520 StringLiteralCheckType Left = 2521 checkFormatStringExpr(S, C->getTrueExpr(), Args, 2522 HasVAListArg, format_idx, firstDataArg, 2523 Type, CallType, InFunctionCall, CheckedVarArgs); 2524 if (Left == SLCT_NotALiteral) 2525 return SLCT_NotALiteral; 2526 StringLiteralCheckType Right = 2527 checkFormatStringExpr(S, C->getFalseExpr(), Args, 2528 HasVAListArg, format_idx, firstDataArg, 2529 Type, CallType, InFunctionCall, CheckedVarArgs); 2530 return Left < Right ? Left : Right; 2531 } 2532 2533 case Stmt::ImplicitCastExprClass: { 2534 E = cast<ImplicitCastExpr>(E)->getSubExpr(); 2535 goto tryAgain; 2536 } 2537 2538 case Stmt::OpaqueValueExprClass: 2539 if (const Expr *src = cast<OpaqueValueExpr>(E)->getSourceExpr()) { 2540 E = src; 2541 goto tryAgain; 2542 } 2543 return SLCT_NotALiteral; 2544 2545 case Stmt::PredefinedExprClass: 2546 // While __func__, etc., are technically not string literals, they 2547 // cannot contain format specifiers and thus are not a security 2548 // liability. 2549 return SLCT_UncheckedLiteral; 2550 2551 case Stmt::DeclRefExprClass: { 2552 const DeclRefExpr *DR = cast<DeclRefExpr>(E); 2553 2554 // As an exception, do not flag errors for variables binding to 2555 // const string literals. 2556 if (const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl())) { 2557 bool isConstant = false; 2558 QualType T = DR->getType(); 2559 2560 if (const ArrayType *AT = S.Context.getAsArrayType(T)) { 2561 isConstant = AT->getElementType().isConstant(S.Context); 2562 } else if (const PointerType *PT = T->getAs<PointerType>()) { 2563 isConstant = T.isConstant(S.Context) && 2564 PT->getPointeeType().isConstant(S.Context); 2565 } else if (T->isObjCObjectPointerType()) { 2566 // In ObjC, there is usually no "const ObjectPointer" type, 2567 // so don't check if the pointee type is constant. 2568 isConstant = T.isConstant(S.Context); 2569 } 2570 2571 if (isConstant) { 2572 if (const Expr *Init = VD->getAnyInitializer()) { 2573 // Look through initializers like const char c[] = { "foo" } 2574 if (const InitListExpr *InitList = dyn_cast<InitListExpr>(Init)) { 2575 if (InitList->isStringLiteralInit()) 2576 Init = InitList->getInit(0)->IgnoreParenImpCasts(); 2577 } 2578 return checkFormatStringExpr(S, Init, Args, 2579 HasVAListArg, format_idx, 2580 firstDataArg, Type, CallType, 2581 /*InFunctionCall*/false, CheckedVarArgs); 2582 } 2583 } 2584 2585 // For vprintf* functions (i.e., HasVAListArg==true), we add a 2586 // special check to see if the format string is a function parameter 2587 // of the function calling the printf function. If the function 2588 // has an attribute indicating it is a printf-like function, then we 2589 // should suppress warnings concerning non-literals being used in a call 2590 // to a vprintf function. For example: 2591 // 2592 // void 2593 // logmessage(char const *fmt __attribute__ (format (printf, 1, 2)), ...){ 2594 // va_list ap; 2595 // va_start(ap, fmt); 2596 // vprintf(fmt, ap); // Do NOT emit a warning about "fmt". 2597 // ... 2598 // } 2599 if (HasVAListArg) { 2600 if (const ParmVarDecl *PV = dyn_cast<ParmVarDecl>(VD)) { 2601 if (const NamedDecl *ND = dyn_cast<NamedDecl>(PV->getDeclContext())) { 2602 int PVIndex = PV->getFunctionScopeIndex() + 1; 2603 for (const auto *PVFormat : ND->specific_attrs<FormatAttr>()) { 2604 // adjust for implicit parameter 2605 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(ND)) 2606 if (MD->isInstance()) 2607 ++PVIndex; 2608 // We also check if the formats are compatible. 2609 // We can't pass a 'scanf' string to a 'printf' function. 2610 if (PVIndex == PVFormat->getFormatIdx() && 2611 Type == S.GetFormatStringType(PVFormat)) 2612 return SLCT_UncheckedLiteral; 2613 } 2614 } 2615 } 2616 } 2617 } 2618 2619 return SLCT_NotALiteral; 2620 } 2621 2622 case Stmt::CallExprClass: 2623 case Stmt::CXXMemberCallExprClass: { 2624 const CallExpr *CE = cast<CallExpr>(E); 2625 if (const NamedDecl *ND = dyn_cast_or_null<NamedDecl>(CE->getCalleeDecl())) { 2626 if (const FormatArgAttr *FA = ND->getAttr<FormatArgAttr>()) { 2627 unsigned ArgIndex = FA->getFormatIdx(); 2628 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(ND)) 2629 if (MD->isInstance()) 2630 --ArgIndex; 2631 const Expr *Arg = CE->getArg(ArgIndex - 1); 2632 2633 return checkFormatStringExpr(S, Arg, Args, 2634 HasVAListArg, format_idx, firstDataArg, 2635 Type, CallType, InFunctionCall, 2636 CheckedVarArgs); 2637 } else if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND)) { 2638 unsigned BuiltinID = FD->getBuiltinID(); 2639 if (BuiltinID == Builtin::BI__builtin___CFStringMakeConstantString || 2640 BuiltinID == Builtin::BI__builtin___NSStringMakeConstantString) { 2641 const Expr *Arg = CE->getArg(0); 2642 return checkFormatStringExpr(S, Arg, Args, 2643 HasVAListArg, format_idx, 2644 firstDataArg, Type, CallType, 2645 InFunctionCall, CheckedVarArgs); 2646 } 2647 } 2648 } 2649 2650 return SLCT_NotALiteral; 2651 } 2652 case Stmt::ObjCStringLiteralClass: 2653 case Stmt::StringLiteralClass: { 2654 const StringLiteral *StrE = nullptr; 2655 2656 if (const ObjCStringLiteral *ObjCFExpr = dyn_cast<ObjCStringLiteral>(E)) 2657 StrE = ObjCFExpr->getString(); 2658 else 2659 StrE = cast<StringLiteral>(E); 2660 2661 if (StrE) { 2662 S.CheckFormatString(StrE, E, Args, HasVAListArg, format_idx, firstDataArg, 2663 Type, InFunctionCall, CallType, CheckedVarArgs); 2664 return SLCT_CheckedLiteral; 2665 } 2666 2667 return SLCT_NotALiteral; 2668 } 2669 2670 default: 2671 return SLCT_NotALiteral; 2672 } 2673 } 2674 2675 Sema::FormatStringType Sema::GetFormatStringType(const FormatAttr *Format) { 2676 return llvm::StringSwitch<FormatStringType>(Format->getType()->getName()) 2677 .Case("scanf", FST_Scanf) 2678 .Cases("printf", "printf0", FST_Printf) 2679 .Cases("NSString", "CFString", FST_NSString) 2680 .Case("strftime", FST_Strftime) 2681 .Case("strfmon", FST_Strfmon) 2682 .Cases("kprintf", "cmn_err", "vcmn_err", "zcmn_err", FST_Kprintf) 2683 .Default(FST_Unknown); 2684 } 2685 2686 /// CheckFormatArguments - Check calls to printf and scanf (and similar 2687 /// functions) for correct use of format strings. 2688 /// Returns true if a format string has been fully checked. 2689 bool Sema::CheckFormatArguments(const FormatAttr *Format, 2690 ArrayRef<const Expr *> Args, 2691 bool IsCXXMember, 2692 VariadicCallType CallType, 2693 SourceLocation Loc, SourceRange Range, 2694 llvm::SmallBitVector &CheckedVarArgs) { 2695 FormatStringInfo FSI; 2696 if (getFormatStringInfo(Format, IsCXXMember, &FSI)) 2697 return CheckFormatArguments(Args, FSI.HasVAListArg, FSI.FormatIdx, 2698 FSI.FirstDataArg, GetFormatStringType(Format), 2699 CallType, Loc, Range, CheckedVarArgs); 2700 return false; 2701 } 2702 2703 bool Sema::CheckFormatArguments(ArrayRef<const Expr *> Args, 2704 bool HasVAListArg, unsigned format_idx, 2705 unsigned firstDataArg, FormatStringType Type, 2706 VariadicCallType CallType, 2707 SourceLocation Loc, SourceRange Range, 2708 llvm::SmallBitVector &CheckedVarArgs) { 2709 // CHECK: printf/scanf-like function is called with no format string. 2710 if (format_idx >= Args.size()) { 2711 Diag(Loc, diag::warn_missing_format_string) << Range; 2712 return false; 2713 } 2714 2715 const Expr *OrigFormatExpr = Args[format_idx]->IgnoreParenCasts(); 2716 2717 // CHECK: format string is not a string literal. 2718 // 2719 // Dynamically generated format strings are difficult to 2720 // automatically vet at compile time. Requiring that format strings 2721 // are string literals: (1) permits the checking of format strings by 2722 // the compiler and thereby (2) can practically remove the source of 2723 // many format string exploits. 2724 2725 // Format string can be either ObjC string (e.g. @"%d") or 2726 // C string (e.g. "%d") 2727 // ObjC string uses the same format specifiers as C string, so we can use 2728 // the same format string checking logic for both ObjC and C strings. 2729 StringLiteralCheckType CT = 2730 checkFormatStringExpr(*this, OrigFormatExpr, Args, HasVAListArg, 2731 format_idx, firstDataArg, Type, CallType, 2732 /*IsFunctionCall*/true, CheckedVarArgs); 2733 if (CT != SLCT_NotALiteral) 2734 // Literal format string found, check done! 2735 return CT == SLCT_CheckedLiteral; 2736 2737 // Strftime is particular as it always uses a single 'time' argument, 2738 // so it is safe to pass a non-literal string. 2739 if (Type == FST_Strftime) 2740 return false; 2741 2742 // Do not emit diag when the string param is a macro expansion and the 2743 // format is either NSString or CFString. This is a hack to prevent 2744 // diag when using the NSLocalizedString and CFCopyLocalizedString macros 2745 // which are usually used in place of NS and CF string literals. 2746 if (Type == FST_NSString && 2747 SourceMgr.isInSystemMacro(Args[format_idx]->getLocStart())) 2748 return false; 2749 2750 // If there are no arguments specified, warn with -Wformat-security, otherwise 2751 // warn only with -Wformat-nonliteral. 2752 if (Args.size() == firstDataArg) 2753 Diag(Args[format_idx]->getLocStart(), 2754 diag::warn_format_nonliteral_noargs) 2755 << OrigFormatExpr->getSourceRange(); 2756 else 2757 Diag(Args[format_idx]->getLocStart(), 2758 diag::warn_format_nonliteral) 2759 << OrigFormatExpr->getSourceRange(); 2760 return false; 2761 } 2762 2763 namespace { 2764 class CheckFormatHandler : public analyze_format_string::FormatStringHandler { 2765 protected: 2766 Sema &S; 2767 const StringLiteral *FExpr; 2768 const Expr *OrigFormatExpr; 2769 const unsigned FirstDataArg; 2770 const unsigned NumDataArgs; 2771 const char *Beg; // Start of format string. 2772 const bool HasVAListArg; 2773 ArrayRef<const Expr *> Args; 2774 unsigned FormatIdx; 2775 llvm::SmallBitVector CoveredArgs; 2776 bool usesPositionalArgs; 2777 bool atFirstArg; 2778 bool inFunctionCall; 2779 Sema::VariadicCallType CallType; 2780 llvm::SmallBitVector &CheckedVarArgs; 2781 public: 2782 CheckFormatHandler(Sema &s, const StringLiteral *fexpr, 2783 const Expr *origFormatExpr, unsigned firstDataArg, 2784 unsigned numDataArgs, const char *beg, bool hasVAListArg, 2785 ArrayRef<const Expr *> Args, 2786 unsigned formatIdx, bool inFunctionCall, 2787 Sema::VariadicCallType callType, 2788 llvm::SmallBitVector &CheckedVarArgs) 2789 : S(s), FExpr(fexpr), OrigFormatExpr(origFormatExpr), 2790 FirstDataArg(firstDataArg), NumDataArgs(numDataArgs), 2791 Beg(beg), HasVAListArg(hasVAListArg), 2792 Args(Args), FormatIdx(formatIdx), 2793 usesPositionalArgs(false), atFirstArg(true), 2794 inFunctionCall(inFunctionCall), CallType(callType), 2795 CheckedVarArgs(CheckedVarArgs) { 2796 CoveredArgs.resize(numDataArgs); 2797 CoveredArgs.reset(); 2798 } 2799 2800 void DoneProcessing(); 2801 2802 void HandleIncompleteSpecifier(const char *startSpecifier, 2803 unsigned specifierLen) override; 2804 2805 void HandleInvalidLengthModifier( 2806 const analyze_format_string::FormatSpecifier &FS, 2807 const analyze_format_string::ConversionSpecifier &CS, 2808 const char *startSpecifier, unsigned specifierLen, 2809 unsigned DiagID); 2810 2811 void HandleNonStandardLengthModifier( 2812 const analyze_format_string::FormatSpecifier &FS, 2813 const char *startSpecifier, unsigned specifierLen); 2814 2815 void HandleNonStandardConversionSpecifier( 2816 const analyze_format_string::ConversionSpecifier &CS, 2817 const char *startSpecifier, unsigned specifierLen); 2818 2819 void HandlePosition(const char *startPos, unsigned posLen) override; 2820 2821 void HandleInvalidPosition(const char *startSpecifier, 2822 unsigned specifierLen, 2823 analyze_format_string::PositionContext p) override; 2824 2825 void HandleZeroPosition(const char *startPos, unsigned posLen) override; 2826 2827 void HandleNullChar(const char *nullCharacter) override; 2828 2829 template <typename Range> 2830 static void EmitFormatDiagnostic(Sema &S, bool inFunctionCall, 2831 const Expr *ArgumentExpr, 2832 PartialDiagnostic PDiag, 2833 SourceLocation StringLoc, 2834 bool IsStringLocation, Range StringRange, 2835 ArrayRef<FixItHint> Fixit = None); 2836 2837 protected: 2838 bool HandleInvalidConversionSpecifier(unsigned argIndex, SourceLocation Loc, 2839 const char *startSpec, 2840 unsigned specifierLen, 2841 const char *csStart, unsigned csLen); 2842 2843 void HandlePositionalNonpositionalArgs(SourceLocation Loc, 2844 const char *startSpec, 2845 unsigned specifierLen); 2846 2847 SourceRange getFormatStringRange(); 2848 CharSourceRange getSpecifierRange(const char *startSpecifier, 2849 unsigned specifierLen); 2850 SourceLocation getLocationOfByte(const char *x); 2851 2852 const Expr *getDataArg(unsigned i) const; 2853 2854 bool CheckNumArgs(const analyze_format_string::FormatSpecifier &FS, 2855 const analyze_format_string::ConversionSpecifier &CS, 2856 const char *startSpecifier, unsigned specifierLen, 2857 unsigned argIndex); 2858 2859 template <typename Range> 2860 void EmitFormatDiagnostic(PartialDiagnostic PDiag, SourceLocation StringLoc, 2861 bool IsStringLocation, Range StringRange, 2862 ArrayRef<FixItHint> Fixit = None); 2863 }; 2864 } 2865 2866 SourceRange CheckFormatHandler::getFormatStringRange() { 2867 return OrigFormatExpr->getSourceRange(); 2868 } 2869 2870 CharSourceRange CheckFormatHandler:: 2871 getSpecifierRange(const char *startSpecifier, unsigned specifierLen) { 2872 SourceLocation Start = getLocationOfByte(startSpecifier); 2873 SourceLocation End = getLocationOfByte(startSpecifier + specifierLen - 1); 2874 2875 // Advance the end SourceLocation by one due to half-open ranges. 2876 End = End.getLocWithOffset(1); 2877 2878 return CharSourceRange::getCharRange(Start, End); 2879 } 2880 2881 SourceLocation CheckFormatHandler::getLocationOfByte(const char *x) { 2882 return S.getLocationOfStringLiteralByte(FExpr, x - Beg); 2883 } 2884 2885 void CheckFormatHandler::HandleIncompleteSpecifier(const char *startSpecifier, 2886 unsigned specifierLen){ 2887 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_incomplete_specifier), 2888 getLocationOfByte(startSpecifier), 2889 /*IsStringLocation*/true, 2890 getSpecifierRange(startSpecifier, specifierLen)); 2891 } 2892 2893 void CheckFormatHandler::HandleInvalidLengthModifier( 2894 const analyze_format_string::FormatSpecifier &FS, 2895 const analyze_format_string::ConversionSpecifier &CS, 2896 const char *startSpecifier, unsigned specifierLen, unsigned DiagID) { 2897 using namespace analyze_format_string; 2898 2899 const LengthModifier &LM = FS.getLengthModifier(); 2900 CharSourceRange LMRange = getSpecifierRange(LM.getStart(), LM.getLength()); 2901 2902 // See if we know how to fix this length modifier. 2903 Optional<LengthModifier> FixedLM = FS.getCorrectedLengthModifier(); 2904 if (FixedLM) { 2905 EmitFormatDiagnostic(S.PDiag(DiagID) << LM.toString() << CS.toString(), 2906 getLocationOfByte(LM.getStart()), 2907 /*IsStringLocation*/true, 2908 getSpecifierRange(startSpecifier, specifierLen)); 2909 2910 S.Diag(getLocationOfByte(LM.getStart()), diag::note_format_fix_specifier) 2911 << FixedLM->toString() 2912 << FixItHint::CreateReplacement(LMRange, FixedLM->toString()); 2913 2914 } else { 2915 FixItHint Hint; 2916 if (DiagID == diag::warn_format_nonsensical_length) 2917 Hint = FixItHint::CreateRemoval(LMRange); 2918 2919 EmitFormatDiagnostic(S.PDiag(DiagID) << LM.toString() << CS.toString(), 2920 getLocationOfByte(LM.getStart()), 2921 /*IsStringLocation*/true, 2922 getSpecifierRange(startSpecifier, specifierLen), 2923 Hint); 2924 } 2925 } 2926 2927 void CheckFormatHandler::HandleNonStandardLengthModifier( 2928 const analyze_format_string::FormatSpecifier &FS, 2929 const char *startSpecifier, unsigned specifierLen) { 2930 using namespace analyze_format_string; 2931 2932 const LengthModifier &LM = FS.getLengthModifier(); 2933 CharSourceRange LMRange = getSpecifierRange(LM.getStart(), LM.getLength()); 2934 2935 // See if we know how to fix this length modifier. 2936 Optional<LengthModifier> FixedLM = FS.getCorrectedLengthModifier(); 2937 if (FixedLM) { 2938 EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard) 2939 << LM.toString() << 0, 2940 getLocationOfByte(LM.getStart()), 2941 /*IsStringLocation*/true, 2942 getSpecifierRange(startSpecifier, specifierLen)); 2943 2944 S.Diag(getLocationOfByte(LM.getStart()), diag::note_format_fix_specifier) 2945 << FixedLM->toString() 2946 << FixItHint::CreateReplacement(LMRange, FixedLM->toString()); 2947 2948 } else { 2949 EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard) 2950 << LM.toString() << 0, 2951 getLocationOfByte(LM.getStart()), 2952 /*IsStringLocation*/true, 2953 getSpecifierRange(startSpecifier, specifierLen)); 2954 } 2955 } 2956 2957 void CheckFormatHandler::HandleNonStandardConversionSpecifier( 2958 const analyze_format_string::ConversionSpecifier &CS, 2959 const char *startSpecifier, unsigned specifierLen) { 2960 using namespace analyze_format_string; 2961 2962 // See if we know how to fix this conversion specifier. 2963 Optional<ConversionSpecifier> FixedCS = CS.getStandardSpecifier(); 2964 if (FixedCS) { 2965 EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard) 2966 << CS.toString() << /*conversion specifier*/1, 2967 getLocationOfByte(CS.getStart()), 2968 /*IsStringLocation*/true, 2969 getSpecifierRange(startSpecifier, specifierLen)); 2970 2971 CharSourceRange CSRange = getSpecifierRange(CS.getStart(), CS.getLength()); 2972 S.Diag(getLocationOfByte(CS.getStart()), diag::note_format_fix_specifier) 2973 << FixedCS->toString() 2974 << FixItHint::CreateReplacement(CSRange, FixedCS->toString()); 2975 } else { 2976 EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard) 2977 << CS.toString() << /*conversion specifier*/1, 2978 getLocationOfByte(CS.getStart()), 2979 /*IsStringLocation*/true, 2980 getSpecifierRange(startSpecifier, specifierLen)); 2981 } 2982 } 2983 2984 void CheckFormatHandler::HandlePosition(const char *startPos, 2985 unsigned posLen) { 2986 EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard_positional_arg), 2987 getLocationOfByte(startPos), 2988 /*IsStringLocation*/true, 2989 getSpecifierRange(startPos, posLen)); 2990 } 2991 2992 void 2993 CheckFormatHandler::HandleInvalidPosition(const char *startPos, unsigned posLen, 2994 analyze_format_string::PositionContext p) { 2995 EmitFormatDiagnostic(S.PDiag(diag::warn_format_invalid_positional_specifier) 2996 << (unsigned) p, 2997 getLocationOfByte(startPos), /*IsStringLocation*/true, 2998 getSpecifierRange(startPos, posLen)); 2999 } 3000 3001 void CheckFormatHandler::HandleZeroPosition(const char *startPos, 3002 unsigned posLen) { 3003 EmitFormatDiagnostic(S.PDiag(diag::warn_format_zero_positional_specifier), 3004 getLocationOfByte(startPos), 3005 /*IsStringLocation*/true, 3006 getSpecifierRange(startPos, posLen)); 3007 } 3008 3009 void CheckFormatHandler::HandleNullChar(const char *nullCharacter) { 3010 if (!isa<ObjCStringLiteral>(OrigFormatExpr)) { 3011 // The presence of a null character is likely an error. 3012 EmitFormatDiagnostic( 3013 S.PDiag(diag::warn_printf_format_string_contains_null_char), 3014 getLocationOfByte(nullCharacter), /*IsStringLocation*/true, 3015 getFormatStringRange()); 3016 } 3017 } 3018 3019 // Note that this may return NULL if there was an error parsing or building 3020 // one of the argument expressions. 3021 const Expr *CheckFormatHandler::getDataArg(unsigned i) const { 3022 return Args[FirstDataArg + i]; 3023 } 3024 3025 void CheckFormatHandler::DoneProcessing() { 3026 // Does the number of data arguments exceed the number of 3027 // format conversions in the format string? 3028 if (!HasVAListArg) { 3029 // Find any arguments that weren't covered. 3030 CoveredArgs.flip(); 3031 signed notCoveredArg = CoveredArgs.find_first(); 3032 if (notCoveredArg >= 0) { 3033 assert((unsigned)notCoveredArg < NumDataArgs); 3034 if (const Expr *E = getDataArg((unsigned) notCoveredArg)) { 3035 SourceLocation Loc = E->getLocStart(); 3036 if (!S.getSourceManager().isInSystemMacro(Loc)) { 3037 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_data_arg_not_used), 3038 Loc, /*IsStringLocation*/false, 3039 getFormatStringRange()); 3040 } 3041 } 3042 } 3043 } 3044 } 3045 3046 bool 3047 CheckFormatHandler::HandleInvalidConversionSpecifier(unsigned argIndex, 3048 SourceLocation Loc, 3049 const char *startSpec, 3050 unsigned specifierLen, 3051 const char *csStart, 3052 unsigned csLen) { 3053 3054 bool keepGoing = true; 3055 if (argIndex < NumDataArgs) { 3056 // Consider the argument coverered, even though the specifier doesn't 3057 // make sense. 3058 CoveredArgs.set(argIndex); 3059 } 3060 else { 3061 // If argIndex exceeds the number of data arguments we 3062 // don't issue a warning because that is just a cascade of warnings (and 3063 // they may have intended '%%' anyway). We don't want to continue processing 3064 // the format string after this point, however, as we will like just get 3065 // gibberish when trying to match arguments. 3066 keepGoing = false; 3067 } 3068 3069 EmitFormatDiagnostic(S.PDiag(diag::warn_format_invalid_conversion) 3070 << StringRef(csStart, csLen), 3071 Loc, /*IsStringLocation*/true, 3072 getSpecifierRange(startSpec, specifierLen)); 3073 3074 return keepGoing; 3075 } 3076 3077 void 3078 CheckFormatHandler::HandlePositionalNonpositionalArgs(SourceLocation Loc, 3079 const char *startSpec, 3080 unsigned specifierLen) { 3081 EmitFormatDiagnostic( 3082 S.PDiag(diag::warn_format_mix_positional_nonpositional_args), 3083 Loc, /*isStringLoc*/true, getSpecifierRange(startSpec, specifierLen)); 3084 } 3085 3086 bool 3087 CheckFormatHandler::CheckNumArgs( 3088 const analyze_format_string::FormatSpecifier &FS, 3089 const analyze_format_string::ConversionSpecifier &CS, 3090 const char *startSpecifier, unsigned specifierLen, unsigned argIndex) { 3091 3092 if (argIndex >= NumDataArgs) { 3093 PartialDiagnostic PDiag = FS.usesPositionalArg() 3094 ? (S.PDiag(diag::warn_printf_positional_arg_exceeds_data_args) 3095 << (argIndex+1) << NumDataArgs) 3096 : S.PDiag(diag::warn_printf_insufficient_data_args); 3097 EmitFormatDiagnostic( 3098 PDiag, getLocationOfByte(CS.getStart()), /*IsStringLocation*/true, 3099 getSpecifierRange(startSpecifier, specifierLen)); 3100 return false; 3101 } 3102 return true; 3103 } 3104 3105 template<typename Range> 3106 void CheckFormatHandler::EmitFormatDiagnostic(PartialDiagnostic PDiag, 3107 SourceLocation Loc, 3108 bool IsStringLocation, 3109 Range StringRange, 3110 ArrayRef<FixItHint> FixIt) { 3111 EmitFormatDiagnostic(S, inFunctionCall, Args[FormatIdx], PDiag, 3112 Loc, IsStringLocation, StringRange, FixIt); 3113 } 3114 3115 /// \brief If the format string is not within the funcion call, emit a note 3116 /// so that the function call and string are in diagnostic messages. 3117 /// 3118 /// \param InFunctionCall if true, the format string is within the function 3119 /// call and only one diagnostic message will be produced. Otherwise, an 3120 /// extra note will be emitted pointing to location of the format string. 3121 /// 3122 /// \param ArgumentExpr the expression that is passed as the format string 3123 /// argument in the function call. Used for getting locations when two 3124 /// diagnostics are emitted. 3125 /// 3126 /// \param PDiag the callee should already have provided any strings for the 3127 /// diagnostic message. This function only adds locations and fixits 3128 /// to diagnostics. 3129 /// 3130 /// \param Loc primary location for diagnostic. If two diagnostics are 3131 /// required, one will be at Loc and a new SourceLocation will be created for 3132 /// the other one. 3133 /// 3134 /// \param IsStringLocation if true, Loc points to the format string should be 3135 /// used for the note. Otherwise, Loc points to the argument list and will 3136 /// be used with PDiag. 3137 /// 3138 /// \param StringRange some or all of the string to highlight. This is 3139 /// templated so it can accept either a CharSourceRange or a SourceRange. 3140 /// 3141 /// \param FixIt optional fix it hint for the format string. 3142 template<typename Range> 3143 void CheckFormatHandler::EmitFormatDiagnostic(Sema &S, bool InFunctionCall, 3144 const Expr *ArgumentExpr, 3145 PartialDiagnostic PDiag, 3146 SourceLocation Loc, 3147 bool IsStringLocation, 3148 Range StringRange, 3149 ArrayRef<FixItHint> FixIt) { 3150 if (InFunctionCall) { 3151 const Sema::SemaDiagnosticBuilder &D = S.Diag(Loc, PDiag); 3152 D << StringRange; 3153 for (ArrayRef<FixItHint>::iterator I = FixIt.begin(), E = FixIt.end(); 3154 I != E; ++I) { 3155 D << *I; 3156 } 3157 } else { 3158 S.Diag(IsStringLocation ? ArgumentExpr->getExprLoc() : Loc, PDiag) 3159 << ArgumentExpr->getSourceRange(); 3160 3161 const Sema::SemaDiagnosticBuilder &Note = 3162 S.Diag(IsStringLocation ? Loc : StringRange.getBegin(), 3163 diag::note_format_string_defined); 3164 3165 Note << StringRange; 3166 for (ArrayRef<FixItHint>::iterator I = FixIt.begin(), E = FixIt.end(); 3167 I != E; ++I) { 3168 Note << *I; 3169 } 3170 } 3171 } 3172 3173 //===--- CHECK: Printf format string checking ------------------------------===// 3174 3175 namespace { 3176 class CheckPrintfHandler : public CheckFormatHandler { 3177 bool ObjCContext; 3178 public: 3179 CheckPrintfHandler(Sema &s, const StringLiteral *fexpr, 3180 const Expr *origFormatExpr, unsigned firstDataArg, 3181 unsigned numDataArgs, bool isObjC, 3182 const char *beg, bool hasVAListArg, 3183 ArrayRef<const Expr *> Args, 3184 unsigned formatIdx, bool inFunctionCall, 3185 Sema::VariadicCallType CallType, 3186 llvm::SmallBitVector &CheckedVarArgs) 3187 : CheckFormatHandler(s, fexpr, origFormatExpr, firstDataArg, 3188 numDataArgs, beg, hasVAListArg, Args, 3189 formatIdx, inFunctionCall, CallType, CheckedVarArgs), 3190 ObjCContext(isObjC) 3191 {} 3192 3193 3194 bool HandleInvalidPrintfConversionSpecifier( 3195 const analyze_printf::PrintfSpecifier &FS, 3196 const char *startSpecifier, 3197 unsigned specifierLen) override; 3198 3199 bool HandlePrintfSpecifier(const analyze_printf::PrintfSpecifier &FS, 3200 const char *startSpecifier, 3201 unsigned specifierLen) override; 3202 bool checkFormatExpr(const analyze_printf::PrintfSpecifier &FS, 3203 const char *StartSpecifier, 3204 unsigned SpecifierLen, 3205 const Expr *E); 3206 3207 bool HandleAmount(const analyze_format_string::OptionalAmount &Amt, unsigned k, 3208 const char *startSpecifier, unsigned specifierLen); 3209 void HandleInvalidAmount(const analyze_printf::PrintfSpecifier &FS, 3210 const analyze_printf::OptionalAmount &Amt, 3211 unsigned type, 3212 const char *startSpecifier, unsigned specifierLen); 3213 void HandleFlag(const analyze_printf::PrintfSpecifier &FS, 3214 const analyze_printf::OptionalFlag &flag, 3215 const char *startSpecifier, unsigned specifierLen); 3216 void HandleIgnoredFlag(const analyze_printf::PrintfSpecifier &FS, 3217 const analyze_printf::OptionalFlag &ignoredFlag, 3218 const analyze_printf::OptionalFlag &flag, 3219 const char *startSpecifier, unsigned specifierLen); 3220 bool checkForCStrMembers(const analyze_printf::ArgType &AT, 3221 const Expr *E); 3222 3223 }; 3224 } 3225 3226 bool CheckPrintfHandler::HandleInvalidPrintfConversionSpecifier( 3227 const analyze_printf::PrintfSpecifier &FS, 3228 const char *startSpecifier, 3229 unsigned specifierLen) { 3230 const analyze_printf::PrintfConversionSpecifier &CS = 3231 FS.getConversionSpecifier(); 3232 3233 return HandleInvalidConversionSpecifier(FS.getArgIndex(), 3234 getLocationOfByte(CS.getStart()), 3235 startSpecifier, specifierLen, 3236 CS.getStart(), CS.getLength()); 3237 } 3238 3239 bool CheckPrintfHandler::HandleAmount( 3240 const analyze_format_string::OptionalAmount &Amt, 3241 unsigned k, const char *startSpecifier, 3242 unsigned specifierLen) { 3243 3244 if (Amt.hasDataArgument()) { 3245 if (!HasVAListArg) { 3246 unsigned argIndex = Amt.getArgIndex(); 3247 if (argIndex >= NumDataArgs) { 3248 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_asterisk_missing_arg) 3249 << k, 3250 getLocationOfByte(Amt.getStart()), 3251 /*IsStringLocation*/true, 3252 getSpecifierRange(startSpecifier, specifierLen)); 3253 // Don't do any more checking. We will just emit 3254 // spurious errors. 3255 return false; 3256 } 3257 3258 // Type check the data argument. It should be an 'int'. 3259 // Although not in conformance with C99, we also allow the argument to be 3260 // an 'unsigned int' as that is a reasonably safe case. GCC also 3261 // doesn't emit a warning for that case. 3262 CoveredArgs.set(argIndex); 3263 const Expr *Arg = getDataArg(argIndex); 3264 if (!Arg) 3265 return false; 3266 3267 QualType T = Arg->getType(); 3268 3269 const analyze_printf::ArgType &AT = Amt.getArgType(S.Context); 3270 assert(AT.isValid()); 3271 3272 if (!AT.matchesType(S.Context, T)) { 3273 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_asterisk_wrong_type) 3274 << k << AT.getRepresentativeTypeName(S.Context) 3275 << T << Arg->getSourceRange(), 3276 getLocationOfByte(Amt.getStart()), 3277 /*IsStringLocation*/true, 3278 getSpecifierRange(startSpecifier, specifierLen)); 3279 // Don't do any more checking. We will just emit 3280 // spurious errors. 3281 return false; 3282 } 3283 } 3284 } 3285 return true; 3286 } 3287 3288 void CheckPrintfHandler::HandleInvalidAmount( 3289 const analyze_printf::PrintfSpecifier &FS, 3290 const analyze_printf::OptionalAmount &Amt, 3291 unsigned type, 3292 const char *startSpecifier, 3293 unsigned specifierLen) { 3294 const analyze_printf::PrintfConversionSpecifier &CS = 3295 FS.getConversionSpecifier(); 3296 3297 FixItHint fixit = 3298 Amt.getHowSpecified() == analyze_printf::OptionalAmount::Constant 3299 ? FixItHint::CreateRemoval(getSpecifierRange(Amt.getStart(), 3300 Amt.getConstantLength())) 3301 : FixItHint(); 3302 3303 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_nonsensical_optional_amount) 3304 << type << CS.toString(), 3305 getLocationOfByte(Amt.getStart()), 3306 /*IsStringLocation*/true, 3307 getSpecifierRange(startSpecifier, specifierLen), 3308 fixit); 3309 } 3310 3311 void CheckPrintfHandler::HandleFlag(const analyze_printf::PrintfSpecifier &FS, 3312 const analyze_printf::OptionalFlag &flag, 3313 const char *startSpecifier, 3314 unsigned specifierLen) { 3315 // Warn about pointless flag with a fixit removal. 3316 const analyze_printf::PrintfConversionSpecifier &CS = 3317 FS.getConversionSpecifier(); 3318 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_nonsensical_flag) 3319 << flag.toString() << CS.toString(), 3320 getLocationOfByte(flag.getPosition()), 3321 /*IsStringLocation*/true, 3322 getSpecifierRange(startSpecifier, specifierLen), 3323 FixItHint::CreateRemoval( 3324 getSpecifierRange(flag.getPosition(), 1))); 3325 } 3326 3327 void CheckPrintfHandler::HandleIgnoredFlag( 3328 const analyze_printf::PrintfSpecifier &FS, 3329 const analyze_printf::OptionalFlag &ignoredFlag, 3330 const analyze_printf::OptionalFlag &flag, 3331 const char *startSpecifier, 3332 unsigned specifierLen) { 3333 // Warn about ignored flag with a fixit removal. 3334 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_ignored_flag) 3335 << ignoredFlag.toString() << flag.toString(), 3336 getLocationOfByte(ignoredFlag.getPosition()), 3337 /*IsStringLocation*/true, 3338 getSpecifierRange(startSpecifier, specifierLen), 3339 FixItHint::CreateRemoval( 3340 getSpecifierRange(ignoredFlag.getPosition(), 1))); 3341 } 3342 3343 // Determines if the specified is a C++ class or struct containing 3344 // a member with the specified name and kind (e.g. a CXXMethodDecl named 3345 // "c_str()"). 3346 template<typename MemberKind> 3347 static llvm::SmallPtrSet<MemberKind*, 1> 3348 CXXRecordMembersNamed(StringRef Name, Sema &S, QualType Ty) { 3349 const RecordType *RT = Ty->getAs<RecordType>(); 3350 llvm::SmallPtrSet<MemberKind*, 1> Results; 3351 3352 if (!RT) 3353 return Results; 3354 const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(RT->getDecl()); 3355 if (!RD || !RD->getDefinition()) 3356 return Results; 3357 3358 LookupResult R(S, &S.Context.Idents.get(Name), SourceLocation(), 3359 Sema::LookupMemberName); 3360 R.suppressDiagnostics(); 3361 3362 // We just need to include all members of the right kind turned up by the 3363 // filter, at this point. 3364 if (S.LookupQualifiedName(R, RT->getDecl())) 3365 for (LookupResult::iterator I = R.begin(), E = R.end(); I != E; ++I) { 3366 NamedDecl *decl = (*I)->getUnderlyingDecl(); 3367 if (MemberKind *FK = dyn_cast<MemberKind>(decl)) 3368 Results.insert(FK); 3369 } 3370 return Results; 3371 } 3372 3373 /// Check if we could call '.c_str()' on an object. 3374 /// 3375 /// FIXME: This returns the wrong results in some cases (if cv-qualifiers don't 3376 /// allow the call, or if it would be ambiguous). 3377 bool Sema::hasCStrMethod(const Expr *E) { 3378 typedef llvm::SmallPtrSet<CXXMethodDecl*, 1> MethodSet; 3379 MethodSet Results = 3380 CXXRecordMembersNamed<CXXMethodDecl>("c_str", *this, E->getType()); 3381 for (MethodSet::iterator MI = Results.begin(), ME = Results.end(); 3382 MI != ME; ++MI) 3383 if ((*MI)->getMinRequiredArguments() == 0) 3384 return true; 3385 return false; 3386 } 3387 3388 // Check if a (w)string was passed when a (w)char* was needed, and offer a 3389 // better diagnostic if so. AT is assumed to be valid. 3390 // Returns true when a c_str() conversion method is found. 3391 bool CheckPrintfHandler::checkForCStrMembers( 3392 const analyze_printf::ArgType &AT, const Expr *E) { 3393 typedef llvm::SmallPtrSet<CXXMethodDecl*, 1> MethodSet; 3394 3395 MethodSet Results = 3396 CXXRecordMembersNamed<CXXMethodDecl>("c_str", S, E->getType()); 3397 3398 for (MethodSet::iterator MI = Results.begin(), ME = Results.end(); 3399 MI != ME; ++MI) { 3400 const CXXMethodDecl *Method = *MI; 3401 if (Method->getMinRequiredArguments() == 0 && 3402 AT.matchesType(S.Context, Method->getReturnType())) { 3403 // FIXME: Suggest parens if the expression needs them. 3404 SourceLocation EndLoc = S.getLocForEndOfToken(E->getLocEnd()); 3405 S.Diag(E->getLocStart(), diag::note_printf_c_str) 3406 << "c_str()" 3407 << FixItHint::CreateInsertion(EndLoc, ".c_str()"); 3408 return true; 3409 } 3410 } 3411 3412 return false; 3413 } 3414 3415 bool 3416 CheckPrintfHandler::HandlePrintfSpecifier(const analyze_printf::PrintfSpecifier 3417 &FS, 3418 const char *startSpecifier, 3419 unsigned specifierLen) { 3420 3421 using namespace analyze_format_string; 3422 using namespace analyze_printf; 3423 const PrintfConversionSpecifier &CS = FS.getConversionSpecifier(); 3424 3425 if (FS.consumesDataArgument()) { 3426 if (atFirstArg) { 3427 atFirstArg = false; 3428 usesPositionalArgs = FS.usesPositionalArg(); 3429 } 3430 else if (usesPositionalArgs != FS.usesPositionalArg()) { 3431 HandlePositionalNonpositionalArgs(getLocationOfByte(CS.getStart()), 3432 startSpecifier, specifierLen); 3433 return false; 3434 } 3435 } 3436 3437 // First check if the field width, precision, and conversion specifier 3438 // have matching data arguments. 3439 if (!HandleAmount(FS.getFieldWidth(), /* field width */ 0, 3440 startSpecifier, specifierLen)) { 3441 return false; 3442 } 3443 3444 if (!HandleAmount(FS.getPrecision(), /* precision */ 1, 3445 startSpecifier, specifierLen)) { 3446 return false; 3447 } 3448 3449 if (!CS.consumesDataArgument()) { 3450 // FIXME: Technically specifying a precision or field width here 3451 // makes no sense. Worth issuing a warning at some point. 3452 return true; 3453 } 3454 3455 // Consume the argument. 3456 unsigned argIndex = FS.getArgIndex(); 3457 if (argIndex < NumDataArgs) { 3458 // The check to see if the argIndex is valid will come later. 3459 // We set the bit here because we may exit early from this 3460 // function if we encounter some other error. 3461 CoveredArgs.set(argIndex); 3462 } 3463 3464 // Check for using an Objective-C specific conversion specifier 3465 // in a non-ObjC literal. 3466 if (!ObjCContext && CS.isObjCArg()) { 3467 return HandleInvalidPrintfConversionSpecifier(FS, startSpecifier, 3468 specifierLen); 3469 } 3470 3471 // Check for invalid use of field width 3472 if (!FS.hasValidFieldWidth()) { 3473 HandleInvalidAmount(FS, FS.getFieldWidth(), /* field width */ 0, 3474 startSpecifier, specifierLen); 3475 } 3476 3477 // Check for invalid use of precision 3478 if (!FS.hasValidPrecision()) { 3479 HandleInvalidAmount(FS, FS.getPrecision(), /* precision */ 1, 3480 startSpecifier, specifierLen); 3481 } 3482 3483 // Check each flag does not conflict with any other component. 3484 if (!FS.hasValidThousandsGroupingPrefix()) 3485 HandleFlag(FS, FS.hasThousandsGrouping(), startSpecifier, specifierLen); 3486 if (!FS.hasValidLeadingZeros()) 3487 HandleFlag(FS, FS.hasLeadingZeros(), startSpecifier, specifierLen); 3488 if (!FS.hasValidPlusPrefix()) 3489 HandleFlag(FS, FS.hasPlusPrefix(), startSpecifier, specifierLen); 3490 if (!FS.hasValidSpacePrefix()) 3491 HandleFlag(FS, FS.hasSpacePrefix(), startSpecifier, specifierLen); 3492 if (!FS.hasValidAlternativeForm()) 3493 HandleFlag(FS, FS.hasAlternativeForm(), startSpecifier, specifierLen); 3494 if (!FS.hasValidLeftJustified()) 3495 HandleFlag(FS, FS.isLeftJustified(), startSpecifier, specifierLen); 3496 3497 // Check that flags are not ignored by another flag 3498 if (FS.hasSpacePrefix() && FS.hasPlusPrefix()) // ' ' ignored by '+' 3499 HandleIgnoredFlag(FS, FS.hasSpacePrefix(), FS.hasPlusPrefix(), 3500 startSpecifier, specifierLen); 3501 if (FS.hasLeadingZeros() && FS.isLeftJustified()) // '0' ignored by '-' 3502 HandleIgnoredFlag(FS, FS.hasLeadingZeros(), FS.isLeftJustified(), 3503 startSpecifier, specifierLen); 3504 3505 // Check the length modifier is valid with the given conversion specifier. 3506 if (!FS.hasValidLengthModifier(S.getASTContext().getTargetInfo())) 3507 HandleInvalidLengthModifier(FS, CS, startSpecifier, specifierLen, 3508 diag::warn_format_nonsensical_length); 3509 else if (!FS.hasStandardLengthModifier()) 3510 HandleNonStandardLengthModifier(FS, startSpecifier, specifierLen); 3511 else if (!FS.hasStandardLengthConversionCombination()) 3512 HandleInvalidLengthModifier(FS, CS, startSpecifier, specifierLen, 3513 diag::warn_format_non_standard_conversion_spec); 3514 3515 if (!FS.hasStandardConversionSpecifier(S.getLangOpts())) 3516 HandleNonStandardConversionSpecifier(CS, startSpecifier, specifierLen); 3517 3518 // The remaining checks depend on the data arguments. 3519 if (HasVAListArg) 3520 return true; 3521 3522 if (!CheckNumArgs(FS, CS, startSpecifier, specifierLen, argIndex)) 3523 return false; 3524 3525 const Expr *Arg = getDataArg(argIndex); 3526 if (!Arg) 3527 return true; 3528 3529 return checkFormatExpr(FS, startSpecifier, specifierLen, Arg); 3530 } 3531 3532 static bool requiresParensToAddCast(const Expr *E) { 3533 // FIXME: We should have a general way to reason about operator 3534 // precedence and whether parens are actually needed here. 3535 // Take care of a few common cases where they aren't. 3536 const Expr *Inside = E->IgnoreImpCasts(); 3537 if (const PseudoObjectExpr *POE = dyn_cast<PseudoObjectExpr>(Inside)) 3538 Inside = POE->getSyntacticForm()->IgnoreImpCasts(); 3539 3540 switch (Inside->getStmtClass()) { 3541 case Stmt::ArraySubscriptExprClass: 3542 case Stmt::CallExprClass: 3543 case Stmt::CharacterLiteralClass: 3544 case Stmt::CXXBoolLiteralExprClass: 3545 case Stmt::DeclRefExprClass: 3546 case Stmt::FloatingLiteralClass: 3547 case Stmt::IntegerLiteralClass: 3548 case Stmt::MemberExprClass: 3549 case Stmt::ObjCArrayLiteralClass: 3550 case Stmt::ObjCBoolLiteralExprClass: 3551 case Stmt::ObjCBoxedExprClass: 3552 case Stmt::ObjCDictionaryLiteralClass: 3553 case Stmt::ObjCEncodeExprClass: 3554 case Stmt::ObjCIvarRefExprClass: 3555 case Stmt::ObjCMessageExprClass: 3556 case Stmt::ObjCPropertyRefExprClass: 3557 case Stmt::ObjCStringLiteralClass: 3558 case Stmt::ObjCSubscriptRefExprClass: 3559 case Stmt::ParenExprClass: 3560 case Stmt::StringLiteralClass: 3561 case Stmt::UnaryOperatorClass: 3562 return false; 3563 default: 3564 return true; 3565 } 3566 } 3567 3568 static std::pair<QualType, StringRef> 3569 shouldNotPrintDirectly(const ASTContext &Context, 3570 QualType IntendedTy, 3571 const Expr *E) { 3572 // Use a 'while' to peel off layers of typedefs. 3573 QualType TyTy = IntendedTy; 3574 while (const TypedefType *UserTy = TyTy->getAs<TypedefType>()) { 3575 StringRef Name = UserTy->getDecl()->getName(); 3576 QualType CastTy = llvm::StringSwitch<QualType>(Name) 3577 .Case("NSInteger", Context.LongTy) 3578 .Case("NSUInteger", Context.UnsignedLongTy) 3579 .Case("SInt32", Context.IntTy) 3580 .Case("UInt32", Context.UnsignedIntTy) 3581 .Default(QualType()); 3582 3583 if (!CastTy.isNull()) 3584 return std::make_pair(CastTy, Name); 3585 3586 TyTy = UserTy->desugar(); 3587 } 3588 3589 // Strip parens if necessary. 3590 if (const ParenExpr *PE = dyn_cast<ParenExpr>(E)) 3591 return shouldNotPrintDirectly(Context, 3592 PE->getSubExpr()->getType(), 3593 PE->getSubExpr()); 3594 3595 // If this is a conditional expression, then its result type is constructed 3596 // via usual arithmetic conversions and thus there might be no necessary 3597 // typedef sugar there. Recurse to operands to check for NSInteger & 3598 // Co. usage condition. 3599 if (const ConditionalOperator *CO = dyn_cast<ConditionalOperator>(E)) { 3600 QualType TrueTy, FalseTy; 3601 StringRef TrueName, FalseName; 3602 3603 std::tie(TrueTy, TrueName) = 3604 shouldNotPrintDirectly(Context, 3605 CO->getTrueExpr()->getType(), 3606 CO->getTrueExpr()); 3607 std::tie(FalseTy, FalseName) = 3608 shouldNotPrintDirectly(Context, 3609 CO->getFalseExpr()->getType(), 3610 CO->getFalseExpr()); 3611 3612 if (TrueTy == FalseTy) 3613 return std::make_pair(TrueTy, TrueName); 3614 else if (TrueTy.isNull()) 3615 return std::make_pair(FalseTy, FalseName); 3616 else if (FalseTy.isNull()) 3617 return std::make_pair(TrueTy, TrueName); 3618 } 3619 3620 return std::make_pair(QualType(), StringRef()); 3621 } 3622 3623 bool 3624 CheckPrintfHandler::checkFormatExpr(const analyze_printf::PrintfSpecifier &FS, 3625 const char *StartSpecifier, 3626 unsigned SpecifierLen, 3627 const Expr *E) { 3628 using namespace analyze_format_string; 3629 using namespace analyze_printf; 3630 // Now type check the data expression that matches the 3631 // format specifier. 3632 const analyze_printf::ArgType &AT = FS.getArgType(S.Context, 3633 ObjCContext); 3634 if (!AT.isValid()) 3635 return true; 3636 3637 QualType ExprTy = E->getType(); 3638 while (const TypeOfExprType *TET = dyn_cast<TypeOfExprType>(ExprTy)) { 3639 ExprTy = TET->getUnderlyingExpr()->getType(); 3640 } 3641 3642 if (AT.matchesType(S.Context, ExprTy)) 3643 return true; 3644 3645 // Look through argument promotions for our error message's reported type. 3646 // This includes the integral and floating promotions, but excludes array 3647 // and function pointer decay; seeing that an argument intended to be a 3648 // string has type 'char [6]' is probably more confusing than 'char *'. 3649 if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) { 3650 if (ICE->getCastKind() == CK_IntegralCast || 3651 ICE->getCastKind() == CK_FloatingCast) { 3652 E = ICE->getSubExpr(); 3653 ExprTy = E->getType(); 3654 3655 // Check if we didn't match because of an implicit cast from a 'char' 3656 // or 'short' to an 'int'. This is done because printf is a varargs 3657 // function. 3658 if (ICE->getType() == S.Context.IntTy || 3659 ICE->getType() == S.Context.UnsignedIntTy) { 3660 // All further checking is done on the subexpression. 3661 if (AT.matchesType(S.Context, ExprTy)) 3662 return true; 3663 } 3664 } 3665 } else if (const CharacterLiteral *CL = dyn_cast<CharacterLiteral>(E)) { 3666 // Special case for 'a', which has type 'int' in C. 3667 // Note, however, that we do /not/ want to treat multibyte constants like 3668 // 'MooV' as characters! This form is deprecated but still exists. 3669 if (ExprTy == S.Context.IntTy) 3670 if (llvm::isUIntN(S.Context.getCharWidth(), CL->getValue())) 3671 ExprTy = S.Context.CharTy; 3672 } 3673 3674 // Look through enums to their underlying type. 3675 bool IsEnum = false; 3676 if (auto EnumTy = ExprTy->getAs<EnumType>()) { 3677 ExprTy = EnumTy->getDecl()->getIntegerType(); 3678 IsEnum = true; 3679 } 3680 3681 // %C in an Objective-C context prints a unichar, not a wchar_t. 3682 // If the argument is an integer of some kind, believe the %C and suggest 3683 // a cast instead of changing the conversion specifier. 3684 QualType IntendedTy = ExprTy; 3685 if (ObjCContext && 3686 FS.getConversionSpecifier().getKind() == ConversionSpecifier::CArg) { 3687 if (ExprTy->isIntegralOrUnscopedEnumerationType() && 3688 !ExprTy->isCharType()) { 3689 // 'unichar' is defined as a typedef of unsigned short, but we should 3690 // prefer using the typedef if it is visible. 3691 IntendedTy = S.Context.UnsignedShortTy; 3692 3693 // While we are here, check if the value is an IntegerLiteral that happens 3694 // to be within the valid range. 3695 if (const IntegerLiteral *IL = dyn_cast<IntegerLiteral>(E)) { 3696 const llvm::APInt &V = IL->getValue(); 3697 if (V.getActiveBits() <= S.Context.getTypeSize(IntendedTy)) 3698 return true; 3699 } 3700 3701 LookupResult Result(S, &S.Context.Idents.get("unichar"), E->getLocStart(), 3702 Sema::LookupOrdinaryName); 3703 if (S.LookupName(Result, S.getCurScope())) { 3704 NamedDecl *ND = Result.getFoundDecl(); 3705 if (TypedefNameDecl *TD = dyn_cast<TypedefNameDecl>(ND)) 3706 if (TD->getUnderlyingType() == IntendedTy) 3707 IntendedTy = S.Context.getTypedefType(TD); 3708 } 3709 } 3710 } 3711 3712 // Special-case some of Darwin's platform-independence types by suggesting 3713 // casts to primitive types that are known to be large enough. 3714 bool ShouldNotPrintDirectly = false; StringRef CastTyName; 3715 if (S.Context.getTargetInfo().getTriple().isOSDarwin()) { 3716 QualType CastTy; 3717 std::tie(CastTy, CastTyName) = shouldNotPrintDirectly(S.Context, IntendedTy, E); 3718 if (!CastTy.isNull()) { 3719 IntendedTy = CastTy; 3720 ShouldNotPrintDirectly = true; 3721 } 3722 } 3723 3724 // We may be able to offer a FixItHint if it is a supported type. 3725 PrintfSpecifier fixedFS = FS; 3726 bool success = fixedFS.fixType(IntendedTy, S.getLangOpts(), 3727 S.Context, ObjCContext); 3728 3729 if (success) { 3730 // Get the fix string from the fixed format specifier 3731 SmallString<16> buf; 3732 llvm::raw_svector_ostream os(buf); 3733 fixedFS.toString(os); 3734 3735 CharSourceRange SpecRange = getSpecifierRange(StartSpecifier, SpecifierLen); 3736 3737 if (IntendedTy == ExprTy && !ShouldNotPrintDirectly) { 3738 // In this case, the specifier is wrong and should be changed to match 3739 // the argument. 3740 EmitFormatDiagnostic( 3741 S.PDiag(diag::warn_format_conversion_argument_type_mismatch) 3742 << AT.getRepresentativeTypeName(S.Context) << IntendedTy << IsEnum 3743 << E->getSourceRange(), 3744 E->getLocStart(), 3745 /*IsStringLocation*/false, 3746 SpecRange, 3747 FixItHint::CreateReplacement(SpecRange, os.str())); 3748 3749 } else { 3750 // The canonical type for formatting this value is different from the 3751 // actual type of the expression. (This occurs, for example, with Darwin's 3752 // NSInteger on 32-bit platforms, where it is typedef'd as 'int', but 3753 // should be printed as 'long' for 64-bit compatibility.) 3754 // Rather than emitting a normal format/argument mismatch, we want to 3755 // add a cast to the recommended type (and correct the format string 3756 // if necessary). 3757 SmallString<16> CastBuf; 3758 llvm::raw_svector_ostream CastFix(CastBuf); 3759 CastFix << "("; 3760 IntendedTy.print(CastFix, S.Context.getPrintingPolicy()); 3761 CastFix << ")"; 3762 3763 SmallVector<FixItHint,4> Hints; 3764 if (!AT.matchesType(S.Context, IntendedTy)) 3765 Hints.push_back(FixItHint::CreateReplacement(SpecRange, os.str())); 3766 3767 if (const CStyleCastExpr *CCast = dyn_cast<CStyleCastExpr>(E)) { 3768 // If there's already a cast present, just replace it. 3769 SourceRange CastRange(CCast->getLParenLoc(), CCast->getRParenLoc()); 3770 Hints.push_back(FixItHint::CreateReplacement(CastRange, CastFix.str())); 3771 3772 } else if (!requiresParensToAddCast(E)) { 3773 // If the expression has high enough precedence, 3774 // just write the C-style cast. 3775 Hints.push_back(FixItHint::CreateInsertion(E->getLocStart(), 3776 CastFix.str())); 3777 } else { 3778 // Otherwise, add parens around the expression as well as the cast. 3779 CastFix << "("; 3780 Hints.push_back(FixItHint::CreateInsertion(E->getLocStart(), 3781 CastFix.str())); 3782 3783 SourceLocation After = S.getLocForEndOfToken(E->getLocEnd()); 3784 Hints.push_back(FixItHint::CreateInsertion(After, ")")); 3785 } 3786 3787 if (ShouldNotPrintDirectly) { 3788 // The expression has a type that should not be printed directly. 3789 // We extract the name from the typedef because we don't want to show 3790 // the underlying type in the diagnostic. 3791 StringRef Name; 3792 if (const TypedefType *TypedefTy = dyn_cast<TypedefType>(ExprTy)) 3793 Name = TypedefTy->getDecl()->getName(); 3794 else 3795 Name = CastTyName; 3796 EmitFormatDiagnostic(S.PDiag(diag::warn_format_argument_needs_cast) 3797 << Name << IntendedTy << IsEnum 3798 << E->getSourceRange(), 3799 E->getLocStart(), /*IsStringLocation=*/false, 3800 SpecRange, Hints); 3801 } else { 3802 // In this case, the expression could be printed using a different 3803 // specifier, but we've decided that the specifier is probably correct 3804 // and we should cast instead. Just use the normal warning message. 3805 EmitFormatDiagnostic( 3806 S.PDiag(diag::warn_format_conversion_argument_type_mismatch) 3807 << AT.getRepresentativeTypeName(S.Context) << ExprTy << IsEnum 3808 << E->getSourceRange(), 3809 E->getLocStart(), /*IsStringLocation*/false, 3810 SpecRange, Hints); 3811 } 3812 } 3813 } else { 3814 const CharSourceRange &CSR = getSpecifierRange(StartSpecifier, 3815 SpecifierLen); 3816 // Since the warning for passing non-POD types to variadic functions 3817 // was deferred until now, we emit a warning for non-POD 3818 // arguments here. 3819 switch (S.isValidVarArgType(ExprTy)) { 3820 case Sema::VAK_Valid: 3821 case Sema::VAK_ValidInCXX11: 3822 EmitFormatDiagnostic( 3823 S.PDiag(diag::warn_format_conversion_argument_type_mismatch) 3824 << AT.getRepresentativeTypeName(S.Context) << ExprTy << IsEnum 3825 << CSR 3826 << E->getSourceRange(), 3827 E->getLocStart(), /*IsStringLocation*/false, CSR); 3828 break; 3829 3830 case Sema::VAK_Undefined: 3831 case Sema::VAK_MSVCUndefined: 3832 EmitFormatDiagnostic( 3833 S.PDiag(diag::warn_non_pod_vararg_with_format_string) 3834 << S.getLangOpts().CPlusPlus11 3835 << ExprTy 3836 << CallType 3837 << AT.getRepresentativeTypeName(S.Context) 3838 << CSR 3839 << E->getSourceRange(), 3840 E->getLocStart(), /*IsStringLocation*/false, CSR); 3841 checkForCStrMembers(AT, E); 3842 break; 3843 3844 case Sema::VAK_Invalid: 3845 if (ExprTy->isObjCObjectType()) 3846 EmitFormatDiagnostic( 3847 S.PDiag(diag::err_cannot_pass_objc_interface_to_vararg_format) 3848 << S.getLangOpts().CPlusPlus11 3849 << ExprTy 3850 << CallType 3851 << AT.getRepresentativeTypeName(S.Context) 3852 << CSR 3853 << E->getSourceRange(), 3854 E->getLocStart(), /*IsStringLocation*/false, CSR); 3855 else 3856 // FIXME: If this is an initializer list, suggest removing the braces 3857 // or inserting a cast to the target type. 3858 S.Diag(E->getLocStart(), diag::err_cannot_pass_to_vararg_format) 3859 << isa<InitListExpr>(E) << ExprTy << CallType 3860 << AT.getRepresentativeTypeName(S.Context) 3861 << E->getSourceRange(); 3862 break; 3863 } 3864 3865 assert(FirstDataArg + FS.getArgIndex() < CheckedVarArgs.size() && 3866 "format string specifier index out of range"); 3867 CheckedVarArgs[FirstDataArg + FS.getArgIndex()] = true; 3868 } 3869 3870 return true; 3871 } 3872 3873 //===--- CHECK: Scanf format string checking ------------------------------===// 3874 3875 namespace { 3876 class CheckScanfHandler : public CheckFormatHandler { 3877 public: 3878 CheckScanfHandler(Sema &s, const StringLiteral *fexpr, 3879 const Expr *origFormatExpr, unsigned firstDataArg, 3880 unsigned numDataArgs, const char *beg, bool hasVAListArg, 3881 ArrayRef<const Expr *> Args, 3882 unsigned formatIdx, bool inFunctionCall, 3883 Sema::VariadicCallType CallType, 3884 llvm::SmallBitVector &CheckedVarArgs) 3885 : CheckFormatHandler(s, fexpr, origFormatExpr, firstDataArg, 3886 numDataArgs, beg, hasVAListArg, 3887 Args, formatIdx, inFunctionCall, CallType, 3888 CheckedVarArgs) 3889 {} 3890 3891 bool HandleScanfSpecifier(const analyze_scanf::ScanfSpecifier &FS, 3892 const char *startSpecifier, 3893 unsigned specifierLen) override; 3894 3895 bool HandleInvalidScanfConversionSpecifier( 3896 const analyze_scanf::ScanfSpecifier &FS, 3897 const char *startSpecifier, 3898 unsigned specifierLen) override; 3899 3900 void HandleIncompleteScanList(const char *start, const char *end) override; 3901 }; 3902 } 3903 3904 void CheckScanfHandler::HandleIncompleteScanList(const char *start, 3905 const char *end) { 3906 EmitFormatDiagnostic(S.PDiag(diag::warn_scanf_scanlist_incomplete), 3907 getLocationOfByte(end), /*IsStringLocation*/true, 3908 getSpecifierRange(start, end - start)); 3909 } 3910 3911 bool CheckScanfHandler::HandleInvalidScanfConversionSpecifier( 3912 const analyze_scanf::ScanfSpecifier &FS, 3913 const char *startSpecifier, 3914 unsigned specifierLen) { 3915 3916 const analyze_scanf::ScanfConversionSpecifier &CS = 3917 FS.getConversionSpecifier(); 3918 3919 return HandleInvalidConversionSpecifier(FS.getArgIndex(), 3920 getLocationOfByte(CS.getStart()), 3921 startSpecifier, specifierLen, 3922 CS.getStart(), CS.getLength()); 3923 } 3924 3925 bool CheckScanfHandler::HandleScanfSpecifier( 3926 const analyze_scanf::ScanfSpecifier &FS, 3927 const char *startSpecifier, 3928 unsigned specifierLen) { 3929 3930 using namespace analyze_scanf; 3931 using namespace analyze_format_string; 3932 3933 const ScanfConversionSpecifier &CS = FS.getConversionSpecifier(); 3934 3935 // Handle case where '%' and '*' don't consume an argument. These shouldn't 3936 // be used to decide if we are using positional arguments consistently. 3937 if (FS.consumesDataArgument()) { 3938 if (atFirstArg) { 3939 atFirstArg = false; 3940 usesPositionalArgs = FS.usesPositionalArg(); 3941 } 3942 else if (usesPositionalArgs != FS.usesPositionalArg()) { 3943 HandlePositionalNonpositionalArgs(getLocationOfByte(CS.getStart()), 3944 startSpecifier, specifierLen); 3945 return false; 3946 } 3947 } 3948 3949 // Check if the field with is non-zero. 3950 const OptionalAmount &Amt = FS.getFieldWidth(); 3951 if (Amt.getHowSpecified() == OptionalAmount::Constant) { 3952 if (Amt.getConstantAmount() == 0) { 3953 const CharSourceRange &R = getSpecifierRange(Amt.getStart(), 3954 Amt.getConstantLength()); 3955 EmitFormatDiagnostic(S.PDiag(diag::warn_scanf_nonzero_width), 3956 getLocationOfByte(Amt.getStart()), 3957 /*IsStringLocation*/true, R, 3958 FixItHint::CreateRemoval(R)); 3959 } 3960 } 3961 3962 if (!FS.consumesDataArgument()) { 3963 // FIXME: Technically specifying a precision or field width here 3964 // makes no sense. Worth issuing a warning at some point. 3965 return true; 3966 } 3967 3968 // Consume the argument. 3969 unsigned argIndex = FS.getArgIndex(); 3970 if (argIndex < NumDataArgs) { 3971 // The check to see if the argIndex is valid will come later. 3972 // We set the bit here because we may exit early from this 3973 // function if we encounter some other error. 3974 CoveredArgs.set(argIndex); 3975 } 3976 3977 // Check the length modifier is valid with the given conversion specifier. 3978 if (!FS.hasValidLengthModifier(S.getASTContext().getTargetInfo())) 3979 HandleInvalidLengthModifier(FS, CS, startSpecifier, specifierLen, 3980 diag::warn_format_nonsensical_length); 3981 else if (!FS.hasStandardLengthModifier()) 3982 HandleNonStandardLengthModifier(FS, startSpecifier, specifierLen); 3983 else if (!FS.hasStandardLengthConversionCombination()) 3984 HandleInvalidLengthModifier(FS, CS, startSpecifier, specifierLen, 3985 diag::warn_format_non_standard_conversion_spec); 3986 3987 if (!FS.hasStandardConversionSpecifier(S.getLangOpts())) 3988 HandleNonStandardConversionSpecifier(CS, startSpecifier, specifierLen); 3989 3990 // The remaining checks depend on the data arguments. 3991 if (HasVAListArg) 3992 return true; 3993 3994 if (!CheckNumArgs(FS, CS, startSpecifier, specifierLen, argIndex)) 3995 return false; 3996 3997 // Check that the argument type matches the format specifier. 3998 const Expr *Ex = getDataArg(argIndex); 3999 if (!Ex) 4000 return true; 4001 4002 const analyze_format_string::ArgType &AT = FS.getArgType(S.Context); 4003 if (AT.isValid() && !AT.matchesType(S.Context, Ex->getType())) { 4004 ScanfSpecifier fixedFS = FS; 4005 bool success = fixedFS.fixType(Ex->getType(), 4006 Ex->IgnoreImpCasts()->getType(), 4007 S.getLangOpts(), S.Context); 4008 4009 if (success) { 4010 // Get the fix string from the fixed format specifier. 4011 SmallString<128> buf; 4012 llvm::raw_svector_ostream os(buf); 4013 fixedFS.toString(os); 4014 4015 EmitFormatDiagnostic( 4016 S.PDiag(diag::warn_format_conversion_argument_type_mismatch) 4017 << AT.getRepresentativeTypeName(S.Context) << Ex->getType() << false 4018 << Ex->getSourceRange(), 4019 Ex->getLocStart(), 4020 /*IsStringLocation*/false, 4021 getSpecifierRange(startSpecifier, specifierLen), 4022 FixItHint::CreateReplacement( 4023 getSpecifierRange(startSpecifier, specifierLen), 4024 os.str())); 4025 } else { 4026 EmitFormatDiagnostic( 4027 S.PDiag(diag::warn_format_conversion_argument_type_mismatch) 4028 << AT.getRepresentativeTypeName(S.Context) << Ex->getType() << false 4029 << Ex->getSourceRange(), 4030 Ex->getLocStart(), 4031 /*IsStringLocation*/false, 4032 getSpecifierRange(startSpecifier, specifierLen)); 4033 } 4034 } 4035 4036 return true; 4037 } 4038 4039 void Sema::CheckFormatString(const StringLiteral *FExpr, 4040 const Expr *OrigFormatExpr, 4041 ArrayRef<const Expr *> Args, 4042 bool HasVAListArg, unsigned format_idx, 4043 unsigned firstDataArg, FormatStringType Type, 4044 bool inFunctionCall, VariadicCallType CallType, 4045 llvm::SmallBitVector &CheckedVarArgs) { 4046 4047 // CHECK: is the format string a wide literal? 4048 if (!FExpr->isAscii() && !FExpr->isUTF8()) { 4049 CheckFormatHandler::EmitFormatDiagnostic( 4050 *this, inFunctionCall, Args[format_idx], 4051 PDiag(diag::warn_format_string_is_wide_literal), FExpr->getLocStart(), 4052 /*IsStringLocation*/true, OrigFormatExpr->getSourceRange()); 4053 return; 4054 } 4055 4056 // Str - The format string. NOTE: this is NOT null-terminated! 4057 StringRef StrRef = FExpr->getString(); 4058 const char *Str = StrRef.data(); 4059 // Account for cases where the string literal is truncated in a declaration. 4060 const ConstantArrayType *T = Context.getAsConstantArrayType(FExpr->getType()); 4061 assert(T && "String literal not of constant array type!"); 4062 size_t TypeSize = T->getSize().getZExtValue(); 4063 size_t StrLen = std::min(std::max(TypeSize, size_t(1)) - 1, StrRef.size()); 4064 const unsigned numDataArgs = Args.size() - firstDataArg; 4065 4066 // Emit a warning if the string literal is truncated and does not contain an 4067 // embedded null character. 4068 if (TypeSize <= StrRef.size() && 4069 StrRef.substr(0, TypeSize).find('\0') == StringRef::npos) { 4070 CheckFormatHandler::EmitFormatDiagnostic( 4071 *this, inFunctionCall, Args[format_idx], 4072 PDiag(diag::warn_printf_format_string_not_null_terminated), 4073 FExpr->getLocStart(), 4074 /*IsStringLocation=*/true, OrigFormatExpr->getSourceRange()); 4075 return; 4076 } 4077 4078 // CHECK: empty format string? 4079 if (StrLen == 0 && numDataArgs > 0) { 4080 CheckFormatHandler::EmitFormatDiagnostic( 4081 *this, inFunctionCall, Args[format_idx], 4082 PDiag(diag::warn_empty_format_string), FExpr->getLocStart(), 4083 /*IsStringLocation*/true, OrigFormatExpr->getSourceRange()); 4084 return; 4085 } 4086 4087 if (Type == FST_Printf || Type == FST_NSString) { 4088 CheckPrintfHandler H(*this, FExpr, OrigFormatExpr, firstDataArg, 4089 numDataArgs, (Type == FST_NSString), 4090 Str, HasVAListArg, Args, format_idx, 4091 inFunctionCall, CallType, CheckedVarArgs); 4092 4093 if (!analyze_format_string::ParsePrintfString(H, Str, Str + StrLen, 4094 getLangOpts(), 4095 Context.getTargetInfo())) 4096 H.DoneProcessing(); 4097 } else if (Type == FST_Scanf) { 4098 CheckScanfHandler H(*this, FExpr, OrigFormatExpr, firstDataArg, numDataArgs, 4099 Str, HasVAListArg, Args, format_idx, 4100 inFunctionCall, CallType, CheckedVarArgs); 4101 4102 if (!analyze_format_string::ParseScanfString(H, Str, Str + StrLen, 4103 getLangOpts(), 4104 Context.getTargetInfo())) 4105 H.DoneProcessing(); 4106 } // TODO: handle other formats 4107 } 4108 4109 bool Sema::FormatStringHasSArg(const StringLiteral *FExpr) { 4110 // Str - The format string. NOTE: this is NOT null-terminated! 4111 StringRef StrRef = FExpr->getString(); 4112 const char *Str = StrRef.data(); 4113 // Account for cases where the string literal is truncated in a declaration. 4114 const ConstantArrayType *T = Context.getAsConstantArrayType(FExpr->getType()); 4115 assert(T && "String literal not of constant array type!"); 4116 size_t TypeSize = T->getSize().getZExtValue(); 4117 size_t StrLen = std::min(std::max(TypeSize, size_t(1)) - 1, StrRef.size()); 4118 return analyze_format_string::ParseFormatStringHasSArg(Str, Str + StrLen, 4119 getLangOpts(), 4120 Context.getTargetInfo()); 4121 } 4122 4123 //===--- CHECK: Warn on use of wrong absolute value function. -------------===// 4124 4125 // Returns the related absolute value function that is larger, of 0 if one 4126 // does not exist. 4127 static unsigned getLargerAbsoluteValueFunction(unsigned AbsFunction) { 4128 switch (AbsFunction) { 4129 default: 4130 return 0; 4131 4132 case Builtin::BI__builtin_abs: 4133 return Builtin::BI__builtin_labs; 4134 case Builtin::BI__builtin_labs: 4135 return Builtin::BI__builtin_llabs; 4136 case Builtin::BI__builtin_llabs: 4137 return 0; 4138 4139 case Builtin::BI__builtin_fabsf: 4140 return Builtin::BI__builtin_fabs; 4141 case Builtin::BI__builtin_fabs: 4142 return Builtin::BI__builtin_fabsl; 4143 case Builtin::BI__builtin_fabsl: 4144 return 0; 4145 4146 case Builtin::BI__builtin_cabsf: 4147 return Builtin::BI__builtin_cabs; 4148 case Builtin::BI__builtin_cabs: 4149 return Builtin::BI__builtin_cabsl; 4150 case Builtin::BI__builtin_cabsl: 4151 return 0; 4152 4153 case Builtin::BIabs: 4154 return Builtin::BIlabs; 4155 case Builtin::BIlabs: 4156 return Builtin::BIllabs; 4157 case Builtin::BIllabs: 4158 return 0; 4159 4160 case Builtin::BIfabsf: 4161 return Builtin::BIfabs; 4162 case Builtin::BIfabs: 4163 return Builtin::BIfabsl; 4164 case Builtin::BIfabsl: 4165 return 0; 4166 4167 case Builtin::BIcabsf: 4168 return Builtin::BIcabs; 4169 case Builtin::BIcabs: 4170 return Builtin::BIcabsl; 4171 case Builtin::BIcabsl: 4172 return 0; 4173 } 4174 } 4175 4176 // Returns the argument type of the absolute value function. 4177 static QualType getAbsoluteValueArgumentType(ASTContext &Context, 4178 unsigned AbsType) { 4179 if (AbsType == 0) 4180 return QualType(); 4181 4182 ASTContext::GetBuiltinTypeError Error = ASTContext::GE_None; 4183 QualType BuiltinType = Context.GetBuiltinType(AbsType, Error); 4184 if (Error != ASTContext::GE_None) 4185 return QualType(); 4186 4187 const FunctionProtoType *FT = BuiltinType->getAs<FunctionProtoType>(); 4188 if (!FT) 4189 return QualType(); 4190 4191 if (FT->getNumParams() != 1) 4192 return QualType(); 4193 4194 return FT->getParamType(0); 4195 } 4196 4197 // Returns the best absolute value function, or zero, based on type and 4198 // current absolute value function. 4199 static unsigned getBestAbsFunction(ASTContext &Context, QualType ArgType, 4200 unsigned AbsFunctionKind) { 4201 unsigned BestKind = 0; 4202 uint64_t ArgSize = Context.getTypeSize(ArgType); 4203 for (unsigned Kind = AbsFunctionKind; Kind != 0; 4204 Kind = getLargerAbsoluteValueFunction(Kind)) { 4205 QualType ParamType = getAbsoluteValueArgumentType(Context, Kind); 4206 if (Context.getTypeSize(ParamType) >= ArgSize) { 4207 if (BestKind == 0) 4208 BestKind = Kind; 4209 else if (Context.hasSameType(ParamType, ArgType)) { 4210 BestKind = Kind; 4211 break; 4212 } 4213 } 4214 } 4215 return BestKind; 4216 } 4217 4218 enum AbsoluteValueKind { 4219 AVK_Integer, 4220 AVK_Floating, 4221 AVK_Complex 4222 }; 4223 4224 static AbsoluteValueKind getAbsoluteValueKind(QualType T) { 4225 if (T->isIntegralOrEnumerationType()) 4226 return AVK_Integer; 4227 if (T->isRealFloatingType()) 4228 return AVK_Floating; 4229 if (T->isAnyComplexType()) 4230 return AVK_Complex; 4231 4232 llvm_unreachable("Type not integer, floating, or complex"); 4233 } 4234 4235 // Changes the absolute value function to a different type. Preserves whether 4236 // the function is a builtin. 4237 static unsigned changeAbsFunction(unsigned AbsKind, 4238 AbsoluteValueKind ValueKind) { 4239 switch (ValueKind) { 4240 case AVK_Integer: 4241 switch (AbsKind) { 4242 default: 4243 return 0; 4244 case Builtin::BI__builtin_fabsf: 4245 case Builtin::BI__builtin_fabs: 4246 case Builtin::BI__builtin_fabsl: 4247 case Builtin::BI__builtin_cabsf: 4248 case Builtin::BI__builtin_cabs: 4249 case Builtin::BI__builtin_cabsl: 4250 return Builtin::BI__builtin_abs; 4251 case Builtin::BIfabsf: 4252 case Builtin::BIfabs: 4253 case Builtin::BIfabsl: 4254 case Builtin::BIcabsf: 4255 case Builtin::BIcabs: 4256 case Builtin::BIcabsl: 4257 return Builtin::BIabs; 4258 } 4259 case AVK_Floating: 4260 switch (AbsKind) { 4261 default: 4262 return 0; 4263 case Builtin::BI__builtin_abs: 4264 case Builtin::BI__builtin_labs: 4265 case Builtin::BI__builtin_llabs: 4266 case Builtin::BI__builtin_cabsf: 4267 case Builtin::BI__builtin_cabs: 4268 case Builtin::BI__builtin_cabsl: 4269 return Builtin::BI__builtin_fabsf; 4270 case Builtin::BIabs: 4271 case Builtin::BIlabs: 4272 case Builtin::BIllabs: 4273 case Builtin::BIcabsf: 4274 case Builtin::BIcabs: 4275 case Builtin::BIcabsl: 4276 return Builtin::BIfabsf; 4277 } 4278 case AVK_Complex: 4279 switch (AbsKind) { 4280 default: 4281 return 0; 4282 case Builtin::BI__builtin_abs: 4283 case Builtin::BI__builtin_labs: 4284 case Builtin::BI__builtin_llabs: 4285 case Builtin::BI__builtin_fabsf: 4286 case Builtin::BI__builtin_fabs: 4287 case Builtin::BI__builtin_fabsl: 4288 return Builtin::BI__builtin_cabsf; 4289 case Builtin::BIabs: 4290 case Builtin::BIlabs: 4291 case Builtin::BIllabs: 4292 case Builtin::BIfabsf: 4293 case Builtin::BIfabs: 4294 case Builtin::BIfabsl: 4295 return Builtin::BIcabsf; 4296 } 4297 } 4298 llvm_unreachable("Unable to convert function"); 4299 } 4300 4301 static unsigned getAbsoluteValueFunctionKind(const FunctionDecl *FDecl) { 4302 const IdentifierInfo *FnInfo = FDecl->getIdentifier(); 4303 if (!FnInfo) 4304 return 0; 4305 4306 switch (FDecl->getBuiltinID()) { 4307 default: 4308 return 0; 4309 case Builtin::BI__builtin_abs: 4310 case Builtin::BI__builtin_fabs: 4311 case Builtin::BI__builtin_fabsf: 4312 case Builtin::BI__builtin_fabsl: 4313 case Builtin::BI__builtin_labs: 4314 case Builtin::BI__builtin_llabs: 4315 case Builtin::BI__builtin_cabs: 4316 case Builtin::BI__builtin_cabsf: 4317 case Builtin::BI__builtin_cabsl: 4318 case Builtin::BIabs: 4319 case Builtin::BIlabs: 4320 case Builtin::BIllabs: 4321 case Builtin::BIfabs: 4322 case Builtin::BIfabsf: 4323 case Builtin::BIfabsl: 4324 case Builtin::BIcabs: 4325 case Builtin::BIcabsf: 4326 case Builtin::BIcabsl: 4327 return FDecl->getBuiltinID(); 4328 } 4329 llvm_unreachable("Unknown Builtin type"); 4330 } 4331 4332 // If the replacement is valid, emit a note with replacement function. 4333 // Additionally, suggest including the proper header if not already included. 4334 static void emitReplacement(Sema &S, SourceLocation Loc, SourceRange Range, 4335 unsigned AbsKind, QualType ArgType) { 4336 bool EmitHeaderHint = true; 4337 const char *HeaderName = nullptr; 4338 const char *FunctionName = nullptr; 4339 if (S.getLangOpts().CPlusPlus && !ArgType->isAnyComplexType()) { 4340 FunctionName = "std::abs"; 4341 if (ArgType->isIntegralOrEnumerationType()) { 4342 HeaderName = "cstdlib"; 4343 } else if (ArgType->isRealFloatingType()) { 4344 HeaderName = "cmath"; 4345 } else { 4346 llvm_unreachable("Invalid Type"); 4347 } 4348 4349 // Lookup all std::abs 4350 if (NamespaceDecl *Std = S.getStdNamespace()) { 4351 LookupResult R(S, &S.Context.Idents.get("abs"), Loc, Sema::LookupAnyName); 4352 R.suppressDiagnostics(); 4353 S.LookupQualifiedName(R, Std); 4354 4355 for (const auto *I : R) { 4356 const FunctionDecl *FDecl = nullptr; 4357 if (const UsingShadowDecl *UsingD = dyn_cast<UsingShadowDecl>(I)) { 4358 FDecl = dyn_cast<FunctionDecl>(UsingD->getTargetDecl()); 4359 } else { 4360 FDecl = dyn_cast<FunctionDecl>(I); 4361 } 4362 if (!FDecl) 4363 continue; 4364 4365 // Found std::abs(), check that they are the right ones. 4366 if (FDecl->getNumParams() != 1) 4367 continue; 4368 4369 // Check that the parameter type can handle the argument. 4370 QualType ParamType = FDecl->getParamDecl(0)->getType(); 4371 if (getAbsoluteValueKind(ArgType) == getAbsoluteValueKind(ParamType) && 4372 S.Context.getTypeSize(ArgType) <= 4373 S.Context.getTypeSize(ParamType)) { 4374 // Found a function, don't need the header hint. 4375 EmitHeaderHint = false; 4376 break; 4377 } 4378 } 4379 } 4380 } else { 4381 FunctionName = S.Context.BuiltinInfo.GetName(AbsKind); 4382 HeaderName = S.Context.BuiltinInfo.getHeaderName(AbsKind); 4383 4384 if (HeaderName) { 4385 DeclarationName DN(&S.Context.Idents.get(FunctionName)); 4386 LookupResult R(S, DN, Loc, Sema::LookupAnyName); 4387 R.suppressDiagnostics(); 4388 S.LookupName(R, S.getCurScope()); 4389 4390 if (R.isSingleResult()) { 4391 FunctionDecl *FD = dyn_cast<FunctionDecl>(R.getFoundDecl()); 4392 if (FD && FD->getBuiltinID() == AbsKind) { 4393 EmitHeaderHint = false; 4394 } else { 4395 return; 4396 } 4397 } else if (!R.empty()) { 4398 return; 4399 } 4400 } 4401 } 4402 4403 S.Diag(Loc, diag::note_replace_abs_function) 4404 << FunctionName << FixItHint::CreateReplacement(Range, FunctionName); 4405 4406 if (!HeaderName) 4407 return; 4408 4409 if (!EmitHeaderHint) 4410 return; 4411 4412 S.Diag(Loc, diag::note_include_header_or_declare) << HeaderName 4413 << FunctionName; 4414 } 4415 4416 static bool IsFunctionStdAbs(const FunctionDecl *FDecl) { 4417 if (!FDecl) 4418 return false; 4419 4420 if (!FDecl->getIdentifier() || !FDecl->getIdentifier()->isStr("abs")) 4421 return false; 4422 4423 const NamespaceDecl *ND = dyn_cast<NamespaceDecl>(FDecl->getDeclContext()); 4424 4425 while (ND && ND->isInlineNamespace()) { 4426 ND = dyn_cast<NamespaceDecl>(ND->getDeclContext()); 4427 } 4428 4429 if (!ND || !ND->getIdentifier() || !ND->getIdentifier()->isStr("std")) 4430 return false; 4431 4432 if (!isa<TranslationUnitDecl>(ND->getDeclContext())) 4433 return false; 4434 4435 return true; 4436 } 4437 4438 // Warn when using the wrong abs() function. 4439 void Sema::CheckAbsoluteValueFunction(const CallExpr *Call, 4440 const FunctionDecl *FDecl, 4441 IdentifierInfo *FnInfo) { 4442 if (Call->getNumArgs() != 1) 4443 return; 4444 4445 unsigned AbsKind = getAbsoluteValueFunctionKind(FDecl); 4446 bool IsStdAbs = IsFunctionStdAbs(FDecl); 4447 if (AbsKind == 0 && !IsStdAbs) 4448 return; 4449 4450 QualType ArgType = Call->getArg(0)->IgnoreParenImpCasts()->getType(); 4451 QualType ParamType = Call->getArg(0)->getType(); 4452 4453 // Unsigned types cannot be negative. Suggest removing the absolute value 4454 // function call. 4455 if (ArgType->isUnsignedIntegerType()) { 4456 const char *FunctionName = 4457 IsStdAbs ? "std::abs" : Context.BuiltinInfo.GetName(AbsKind); 4458 Diag(Call->getExprLoc(), diag::warn_unsigned_abs) << ArgType << ParamType; 4459 Diag(Call->getExprLoc(), diag::note_remove_abs) 4460 << FunctionName 4461 << FixItHint::CreateRemoval(Call->getCallee()->getSourceRange()); 4462 return; 4463 } 4464 4465 // std::abs has overloads which prevent most of the absolute value problems 4466 // from occurring. 4467 if (IsStdAbs) 4468 return; 4469 4470 AbsoluteValueKind ArgValueKind = getAbsoluteValueKind(ArgType); 4471 AbsoluteValueKind ParamValueKind = getAbsoluteValueKind(ParamType); 4472 4473 // The argument and parameter are the same kind. Check if they are the right 4474 // size. 4475 if (ArgValueKind == ParamValueKind) { 4476 if (Context.getTypeSize(ArgType) <= Context.getTypeSize(ParamType)) 4477 return; 4478 4479 unsigned NewAbsKind = getBestAbsFunction(Context, ArgType, AbsKind); 4480 Diag(Call->getExprLoc(), diag::warn_abs_too_small) 4481 << FDecl << ArgType << ParamType; 4482 4483 if (NewAbsKind == 0) 4484 return; 4485 4486 emitReplacement(*this, Call->getExprLoc(), 4487 Call->getCallee()->getSourceRange(), NewAbsKind, ArgType); 4488 return; 4489 } 4490 4491 // ArgValueKind != ParamValueKind 4492 // The wrong type of absolute value function was used. Attempt to find the 4493 // proper one. 4494 unsigned NewAbsKind = changeAbsFunction(AbsKind, ArgValueKind); 4495 NewAbsKind = getBestAbsFunction(Context, ArgType, NewAbsKind); 4496 if (NewAbsKind == 0) 4497 return; 4498 4499 Diag(Call->getExprLoc(), diag::warn_wrong_absolute_value_type) 4500 << FDecl << ParamValueKind << ArgValueKind; 4501 4502 emitReplacement(*this, Call->getExprLoc(), 4503 Call->getCallee()->getSourceRange(), NewAbsKind, ArgType); 4504 return; 4505 } 4506 4507 //===--- CHECK: Standard memory functions ---------------------------------===// 4508 4509 /// \brief Takes the expression passed to the size_t parameter of functions 4510 /// such as memcmp, strncat, etc and warns if it's a comparison. 4511 /// 4512 /// This is to catch typos like `if (memcmp(&a, &b, sizeof(a) > 0))`. 4513 static bool CheckMemorySizeofForComparison(Sema &S, const Expr *E, 4514 IdentifierInfo *FnName, 4515 SourceLocation FnLoc, 4516 SourceLocation RParenLoc) { 4517 const BinaryOperator *Size = dyn_cast<BinaryOperator>(E); 4518 if (!Size) 4519 return false; 4520 4521 // if E is binop and op is >, <, >=, <=, ==, &&, ||: 4522 if (!Size->isComparisonOp() && !Size->isEqualityOp() && !Size->isLogicalOp()) 4523 return false; 4524 4525 SourceRange SizeRange = Size->getSourceRange(); 4526 S.Diag(Size->getOperatorLoc(), diag::warn_memsize_comparison) 4527 << SizeRange << FnName; 4528 S.Diag(FnLoc, diag::note_memsize_comparison_paren) 4529 << FnName << FixItHint::CreateInsertion( 4530 S.getLocForEndOfToken(Size->getLHS()->getLocEnd()), ")") 4531 << FixItHint::CreateRemoval(RParenLoc); 4532 S.Diag(SizeRange.getBegin(), diag::note_memsize_comparison_cast_silence) 4533 << FixItHint::CreateInsertion(SizeRange.getBegin(), "(size_t)(") 4534 << FixItHint::CreateInsertion(S.getLocForEndOfToken(SizeRange.getEnd()), 4535 ")"); 4536 4537 return true; 4538 } 4539 4540 /// \brief Determine whether the given type is or contains a dynamic class type 4541 /// (e.g., whether it has a vtable). 4542 static const CXXRecordDecl *getContainedDynamicClass(QualType T, 4543 bool &IsContained) { 4544 // Look through array types while ignoring qualifiers. 4545 const Type *Ty = T->getBaseElementTypeUnsafe(); 4546 IsContained = false; 4547 4548 const CXXRecordDecl *RD = Ty->getAsCXXRecordDecl(); 4549 RD = RD ? RD->getDefinition() : nullptr; 4550 if (!RD) 4551 return nullptr; 4552 4553 if (RD->isDynamicClass()) 4554 return RD; 4555 4556 // Check all the fields. If any bases were dynamic, the class is dynamic. 4557 // It's impossible for a class to transitively contain itself by value, so 4558 // infinite recursion is impossible. 4559 for (auto *FD : RD->fields()) { 4560 bool SubContained; 4561 if (const CXXRecordDecl *ContainedRD = 4562 getContainedDynamicClass(FD->getType(), SubContained)) { 4563 IsContained = true; 4564 return ContainedRD; 4565 } 4566 } 4567 4568 return nullptr; 4569 } 4570 4571 /// \brief If E is a sizeof expression, returns its argument expression, 4572 /// otherwise returns NULL. 4573 static const Expr *getSizeOfExprArg(const Expr* E) { 4574 if (const UnaryExprOrTypeTraitExpr *SizeOf = 4575 dyn_cast<UnaryExprOrTypeTraitExpr>(E)) 4576 if (SizeOf->getKind() == clang::UETT_SizeOf && !SizeOf->isArgumentType()) 4577 return SizeOf->getArgumentExpr()->IgnoreParenImpCasts(); 4578 4579 return nullptr; 4580 } 4581 4582 /// \brief If E is a sizeof expression, returns its argument type. 4583 static QualType getSizeOfArgType(const Expr* E) { 4584 if (const UnaryExprOrTypeTraitExpr *SizeOf = 4585 dyn_cast<UnaryExprOrTypeTraitExpr>(E)) 4586 if (SizeOf->getKind() == clang::UETT_SizeOf) 4587 return SizeOf->getTypeOfArgument(); 4588 4589 return QualType(); 4590 } 4591 4592 /// \brief Check for dangerous or invalid arguments to memset(). 4593 /// 4594 /// This issues warnings on known problematic, dangerous or unspecified 4595 /// arguments to the standard 'memset', 'memcpy', 'memmove', and 'memcmp' 4596 /// function calls. 4597 /// 4598 /// \param Call The call expression to diagnose. 4599 void Sema::CheckMemaccessArguments(const CallExpr *Call, 4600 unsigned BId, 4601 IdentifierInfo *FnName) { 4602 assert(BId != 0); 4603 4604 // It is possible to have a non-standard definition of memset. Validate 4605 // we have enough arguments, and if not, abort further checking. 4606 unsigned ExpectedNumArgs = (BId == Builtin::BIstrndup ? 2 : 3); 4607 if (Call->getNumArgs() < ExpectedNumArgs) 4608 return; 4609 4610 unsigned LastArg = (BId == Builtin::BImemset || 4611 BId == Builtin::BIstrndup ? 1 : 2); 4612 unsigned LenArg = (BId == Builtin::BIstrndup ? 1 : 2); 4613 const Expr *LenExpr = Call->getArg(LenArg)->IgnoreParenImpCasts(); 4614 4615 if (CheckMemorySizeofForComparison(*this, LenExpr, FnName, 4616 Call->getLocStart(), Call->getRParenLoc())) 4617 return; 4618 4619 // We have special checking when the length is a sizeof expression. 4620 QualType SizeOfArgTy = getSizeOfArgType(LenExpr); 4621 const Expr *SizeOfArg = getSizeOfExprArg(LenExpr); 4622 llvm::FoldingSetNodeID SizeOfArgID; 4623 4624 for (unsigned ArgIdx = 0; ArgIdx != LastArg; ++ArgIdx) { 4625 const Expr *Dest = Call->getArg(ArgIdx)->IgnoreParenImpCasts(); 4626 SourceRange ArgRange = Call->getArg(ArgIdx)->getSourceRange(); 4627 4628 QualType DestTy = Dest->getType(); 4629 if (const PointerType *DestPtrTy = DestTy->getAs<PointerType>()) { 4630 QualType PointeeTy = DestPtrTy->getPointeeType(); 4631 4632 // Never warn about void type pointers. This can be used to suppress 4633 // false positives. 4634 if (PointeeTy->isVoidType()) 4635 continue; 4636 4637 // Catch "memset(p, 0, sizeof(p))" -- needs to be sizeof(*p). Do this by 4638 // actually comparing the expressions for equality. Because computing the 4639 // expression IDs can be expensive, we only do this if the diagnostic is 4640 // enabled. 4641 if (SizeOfArg && 4642 !Diags.isIgnored(diag::warn_sizeof_pointer_expr_memaccess, 4643 SizeOfArg->getExprLoc())) { 4644 // We only compute IDs for expressions if the warning is enabled, and 4645 // cache the sizeof arg's ID. 4646 if (SizeOfArgID == llvm::FoldingSetNodeID()) 4647 SizeOfArg->Profile(SizeOfArgID, Context, true); 4648 llvm::FoldingSetNodeID DestID; 4649 Dest->Profile(DestID, Context, true); 4650 if (DestID == SizeOfArgID) { 4651 // TODO: For strncpy() and friends, this could suggest sizeof(dst) 4652 // over sizeof(src) as well. 4653 unsigned ActionIdx = 0; // Default is to suggest dereferencing. 4654 StringRef ReadableName = FnName->getName(); 4655 4656 if (const UnaryOperator *UnaryOp = dyn_cast<UnaryOperator>(Dest)) 4657 if (UnaryOp->getOpcode() == UO_AddrOf) 4658 ActionIdx = 1; // If its an address-of operator, just remove it. 4659 if (!PointeeTy->isIncompleteType() && 4660 (Context.getTypeSize(PointeeTy) == Context.getCharWidth())) 4661 ActionIdx = 2; // If the pointee's size is sizeof(char), 4662 // suggest an explicit length. 4663 4664 // If the function is defined as a builtin macro, do not show macro 4665 // expansion. 4666 SourceLocation SL = SizeOfArg->getExprLoc(); 4667 SourceRange DSR = Dest->getSourceRange(); 4668 SourceRange SSR = SizeOfArg->getSourceRange(); 4669 SourceManager &SM = getSourceManager(); 4670 4671 if (SM.isMacroArgExpansion(SL)) { 4672 ReadableName = Lexer::getImmediateMacroName(SL, SM, LangOpts); 4673 SL = SM.getSpellingLoc(SL); 4674 DSR = SourceRange(SM.getSpellingLoc(DSR.getBegin()), 4675 SM.getSpellingLoc(DSR.getEnd())); 4676 SSR = SourceRange(SM.getSpellingLoc(SSR.getBegin()), 4677 SM.getSpellingLoc(SSR.getEnd())); 4678 } 4679 4680 DiagRuntimeBehavior(SL, SizeOfArg, 4681 PDiag(diag::warn_sizeof_pointer_expr_memaccess) 4682 << ReadableName 4683 << PointeeTy 4684 << DestTy 4685 << DSR 4686 << SSR); 4687 DiagRuntimeBehavior(SL, SizeOfArg, 4688 PDiag(diag::warn_sizeof_pointer_expr_memaccess_note) 4689 << ActionIdx 4690 << SSR); 4691 4692 break; 4693 } 4694 } 4695 4696 // Also check for cases where the sizeof argument is the exact same 4697 // type as the memory argument, and where it points to a user-defined 4698 // record type. 4699 if (SizeOfArgTy != QualType()) { 4700 if (PointeeTy->isRecordType() && 4701 Context.typesAreCompatible(SizeOfArgTy, DestTy)) { 4702 DiagRuntimeBehavior(LenExpr->getExprLoc(), Dest, 4703 PDiag(diag::warn_sizeof_pointer_type_memaccess) 4704 << FnName << SizeOfArgTy << ArgIdx 4705 << PointeeTy << Dest->getSourceRange() 4706 << LenExpr->getSourceRange()); 4707 break; 4708 } 4709 } 4710 4711 // Always complain about dynamic classes. 4712 bool IsContained; 4713 if (const CXXRecordDecl *ContainedRD = 4714 getContainedDynamicClass(PointeeTy, IsContained)) { 4715 4716 unsigned OperationType = 0; 4717 // "overwritten" if we're warning about the destination for any call 4718 // but memcmp; otherwise a verb appropriate to the call. 4719 if (ArgIdx != 0 || BId == Builtin::BImemcmp) { 4720 if (BId == Builtin::BImemcpy) 4721 OperationType = 1; 4722 else if(BId == Builtin::BImemmove) 4723 OperationType = 2; 4724 else if (BId == Builtin::BImemcmp) 4725 OperationType = 3; 4726 } 4727 4728 DiagRuntimeBehavior( 4729 Dest->getExprLoc(), Dest, 4730 PDiag(diag::warn_dyn_class_memaccess) 4731 << (BId == Builtin::BImemcmp ? ArgIdx + 2 : ArgIdx) 4732 << FnName << IsContained << ContainedRD << OperationType 4733 << Call->getCallee()->getSourceRange()); 4734 } else if (PointeeTy.hasNonTrivialObjCLifetime() && 4735 BId != Builtin::BImemset) 4736 DiagRuntimeBehavior( 4737 Dest->getExprLoc(), Dest, 4738 PDiag(diag::warn_arc_object_memaccess) 4739 << ArgIdx << FnName << PointeeTy 4740 << Call->getCallee()->getSourceRange()); 4741 else 4742 continue; 4743 4744 DiagRuntimeBehavior( 4745 Dest->getExprLoc(), Dest, 4746 PDiag(diag::note_bad_memaccess_silence) 4747 << FixItHint::CreateInsertion(ArgRange.getBegin(), "(void*)")); 4748 break; 4749 } 4750 } 4751 } 4752 4753 // A little helper routine: ignore addition and subtraction of integer literals. 4754 // This intentionally does not ignore all integer constant expressions because 4755 // we don't want to remove sizeof(). 4756 static const Expr *ignoreLiteralAdditions(const Expr *Ex, ASTContext &Ctx) { 4757 Ex = Ex->IgnoreParenCasts(); 4758 4759 for (;;) { 4760 const BinaryOperator * BO = dyn_cast<BinaryOperator>(Ex); 4761 if (!BO || !BO->isAdditiveOp()) 4762 break; 4763 4764 const Expr *RHS = BO->getRHS()->IgnoreParenCasts(); 4765 const Expr *LHS = BO->getLHS()->IgnoreParenCasts(); 4766 4767 if (isa<IntegerLiteral>(RHS)) 4768 Ex = LHS; 4769 else if (isa<IntegerLiteral>(LHS)) 4770 Ex = RHS; 4771 else 4772 break; 4773 } 4774 4775 return Ex; 4776 } 4777 4778 static bool isConstantSizeArrayWithMoreThanOneElement(QualType Ty, 4779 ASTContext &Context) { 4780 // Only handle constant-sized or VLAs, but not flexible members. 4781 if (const ConstantArrayType *CAT = Context.getAsConstantArrayType(Ty)) { 4782 // Only issue the FIXIT for arrays of size > 1. 4783 if (CAT->getSize().getSExtValue() <= 1) 4784 return false; 4785 } else if (!Ty->isVariableArrayType()) { 4786 return false; 4787 } 4788 return true; 4789 } 4790 4791 // Warn if the user has made the 'size' argument to strlcpy or strlcat 4792 // be the size of the source, instead of the destination. 4793 void Sema::CheckStrlcpycatArguments(const CallExpr *Call, 4794 IdentifierInfo *FnName) { 4795 4796 // Don't crash if the user has the wrong number of arguments 4797 unsigned NumArgs = Call->getNumArgs(); 4798 if ((NumArgs != 3) && (NumArgs != 4)) 4799 return; 4800 4801 const Expr *SrcArg = ignoreLiteralAdditions(Call->getArg(1), Context); 4802 const Expr *SizeArg = ignoreLiteralAdditions(Call->getArg(2), Context); 4803 const Expr *CompareWithSrc = nullptr; 4804 4805 if (CheckMemorySizeofForComparison(*this, SizeArg, FnName, 4806 Call->getLocStart(), Call->getRParenLoc())) 4807 return; 4808 4809 // Look for 'strlcpy(dst, x, sizeof(x))' 4810 if (const Expr *Ex = getSizeOfExprArg(SizeArg)) 4811 CompareWithSrc = Ex; 4812 else { 4813 // Look for 'strlcpy(dst, x, strlen(x))' 4814 if (const CallExpr *SizeCall = dyn_cast<CallExpr>(SizeArg)) { 4815 if (SizeCall->getBuiltinCallee() == Builtin::BIstrlen && 4816 SizeCall->getNumArgs() == 1) 4817 CompareWithSrc = ignoreLiteralAdditions(SizeCall->getArg(0), Context); 4818 } 4819 } 4820 4821 if (!CompareWithSrc) 4822 return; 4823 4824 // Determine if the argument to sizeof/strlen is equal to the source 4825 // argument. In principle there's all kinds of things you could do 4826 // here, for instance creating an == expression and evaluating it with 4827 // EvaluateAsBooleanCondition, but this uses a more direct technique: 4828 const DeclRefExpr *SrcArgDRE = dyn_cast<DeclRefExpr>(SrcArg); 4829 if (!SrcArgDRE) 4830 return; 4831 4832 const DeclRefExpr *CompareWithSrcDRE = dyn_cast<DeclRefExpr>(CompareWithSrc); 4833 if (!CompareWithSrcDRE || 4834 SrcArgDRE->getDecl() != CompareWithSrcDRE->getDecl()) 4835 return; 4836 4837 const Expr *OriginalSizeArg = Call->getArg(2); 4838 Diag(CompareWithSrcDRE->getLocStart(), diag::warn_strlcpycat_wrong_size) 4839 << OriginalSizeArg->getSourceRange() << FnName; 4840 4841 // Output a FIXIT hint if the destination is an array (rather than a 4842 // pointer to an array). This could be enhanced to handle some 4843 // pointers if we know the actual size, like if DstArg is 'array+2' 4844 // we could say 'sizeof(array)-2'. 4845 const Expr *DstArg = Call->getArg(0)->IgnoreParenImpCasts(); 4846 if (!isConstantSizeArrayWithMoreThanOneElement(DstArg->getType(), Context)) 4847 return; 4848 4849 SmallString<128> sizeString; 4850 llvm::raw_svector_ostream OS(sizeString); 4851 OS << "sizeof("; 4852 DstArg->printPretty(OS, nullptr, getPrintingPolicy()); 4853 OS << ")"; 4854 4855 Diag(OriginalSizeArg->getLocStart(), diag::note_strlcpycat_wrong_size) 4856 << FixItHint::CreateReplacement(OriginalSizeArg->getSourceRange(), 4857 OS.str()); 4858 } 4859 4860 /// Check if two expressions refer to the same declaration. 4861 static bool referToTheSameDecl(const Expr *E1, const Expr *E2) { 4862 if (const DeclRefExpr *D1 = dyn_cast_or_null<DeclRefExpr>(E1)) 4863 if (const DeclRefExpr *D2 = dyn_cast_or_null<DeclRefExpr>(E2)) 4864 return D1->getDecl() == D2->getDecl(); 4865 return false; 4866 } 4867 4868 static const Expr *getStrlenExprArg(const Expr *E) { 4869 if (const CallExpr *CE = dyn_cast<CallExpr>(E)) { 4870 const FunctionDecl *FD = CE->getDirectCallee(); 4871 if (!FD || FD->getMemoryFunctionKind() != Builtin::BIstrlen) 4872 return nullptr; 4873 return CE->getArg(0)->IgnoreParenCasts(); 4874 } 4875 return nullptr; 4876 } 4877 4878 // Warn on anti-patterns as the 'size' argument to strncat. 4879 // The correct size argument should look like following: 4880 // strncat(dst, src, sizeof(dst) - strlen(dest) - 1); 4881 void Sema::CheckStrncatArguments(const CallExpr *CE, 4882 IdentifierInfo *FnName) { 4883 // Don't crash if the user has the wrong number of arguments. 4884 if (CE->getNumArgs() < 3) 4885 return; 4886 const Expr *DstArg = CE->getArg(0)->IgnoreParenCasts(); 4887 const Expr *SrcArg = CE->getArg(1)->IgnoreParenCasts(); 4888 const Expr *LenArg = CE->getArg(2)->IgnoreParenCasts(); 4889 4890 if (CheckMemorySizeofForComparison(*this, LenArg, FnName, CE->getLocStart(), 4891 CE->getRParenLoc())) 4892 return; 4893 4894 // Identify common expressions, which are wrongly used as the size argument 4895 // to strncat and may lead to buffer overflows. 4896 unsigned PatternType = 0; 4897 if (const Expr *SizeOfArg = getSizeOfExprArg(LenArg)) { 4898 // - sizeof(dst) 4899 if (referToTheSameDecl(SizeOfArg, DstArg)) 4900 PatternType = 1; 4901 // - sizeof(src) 4902 else if (referToTheSameDecl(SizeOfArg, SrcArg)) 4903 PatternType = 2; 4904 } else if (const BinaryOperator *BE = dyn_cast<BinaryOperator>(LenArg)) { 4905 if (BE->getOpcode() == BO_Sub) { 4906 const Expr *L = BE->getLHS()->IgnoreParenCasts(); 4907 const Expr *R = BE->getRHS()->IgnoreParenCasts(); 4908 // - sizeof(dst) - strlen(dst) 4909 if (referToTheSameDecl(DstArg, getSizeOfExprArg(L)) && 4910 referToTheSameDecl(DstArg, getStrlenExprArg(R))) 4911 PatternType = 1; 4912 // - sizeof(src) - (anything) 4913 else if (referToTheSameDecl(SrcArg, getSizeOfExprArg(L))) 4914 PatternType = 2; 4915 } 4916 } 4917 4918 if (PatternType == 0) 4919 return; 4920 4921 // Generate the diagnostic. 4922 SourceLocation SL = LenArg->getLocStart(); 4923 SourceRange SR = LenArg->getSourceRange(); 4924 SourceManager &SM = getSourceManager(); 4925 4926 // If the function is defined as a builtin macro, do not show macro expansion. 4927 if (SM.isMacroArgExpansion(SL)) { 4928 SL = SM.getSpellingLoc(SL); 4929 SR = SourceRange(SM.getSpellingLoc(SR.getBegin()), 4930 SM.getSpellingLoc(SR.getEnd())); 4931 } 4932 4933 // Check if the destination is an array (rather than a pointer to an array). 4934 QualType DstTy = DstArg->getType(); 4935 bool isKnownSizeArray = isConstantSizeArrayWithMoreThanOneElement(DstTy, 4936 Context); 4937 if (!isKnownSizeArray) { 4938 if (PatternType == 1) 4939 Diag(SL, diag::warn_strncat_wrong_size) << SR; 4940 else 4941 Diag(SL, diag::warn_strncat_src_size) << SR; 4942 return; 4943 } 4944 4945 if (PatternType == 1) 4946 Diag(SL, diag::warn_strncat_large_size) << SR; 4947 else 4948 Diag(SL, diag::warn_strncat_src_size) << SR; 4949 4950 SmallString<128> sizeString; 4951 llvm::raw_svector_ostream OS(sizeString); 4952 OS << "sizeof("; 4953 DstArg->printPretty(OS, nullptr, getPrintingPolicy()); 4954 OS << ") - "; 4955 OS << "strlen("; 4956 DstArg->printPretty(OS, nullptr, getPrintingPolicy()); 4957 OS << ") - 1"; 4958 4959 Diag(SL, diag::note_strncat_wrong_size) 4960 << FixItHint::CreateReplacement(SR, OS.str()); 4961 } 4962 4963 //===--- CHECK: Return Address of Stack Variable --------------------------===// 4964 4965 static Expr *EvalVal(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars, 4966 Decl *ParentDecl); 4967 static Expr *EvalAddr(Expr* E, SmallVectorImpl<DeclRefExpr *> &refVars, 4968 Decl *ParentDecl); 4969 4970 /// CheckReturnStackAddr - Check if a return statement returns the address 4971 /// of a stack variable. 4972 static void 4973 CheckReturnStackAddr(Sema &S, Expr *RetValExp, QualType lhsType, 4974 SourceLocation ReturnLoc) { 4975 4976 Expr *stackE = nullptr; 4977 SmallVector<DeclRefExpr *, 8> refVars; 4978 4979 // Perform checking for returned stack addresses, local blocks, 4980 // label addresses or references to temporaries. 4981 if (lhsType->isPointerType() || 4982 (!S.getLangOpts().ObjCAutoRefCount && lhsType->isBlockPointerType())) { 4983 stackE = EvalAddr(RetValExp, refVars, /*ParentDecl=*/nullptr); 4984 } else if (lhsType->isReferenceType()) { 4985 stackE = EvalVal(RetValExp, refVars, /*ParentDecl=*/nullptr); 4986 } 4987 4988 if (!stackE) 4989 return; // Nothing suspicious was found. 4990 4991 SourceLocation diagLoc; 4992 SourceRange diagRange; 4993 if (refVars.empty()) { 4994 diagLoc = stackE->getLocStart(); 4995 diagRange = stackE->getSourceRange(); 4996 } else { 4997 // We followed through a reference variable. 'stackE' contains the 4998 // problematic expression but we will warn at the return statement pointing 4999 // at the reference variable. We will later display the "trail" of 5000 // reference variables using notes. 5001 diagLoc = refVars[0]->getLocStart(); 5002 diagRange = refVars[0]->getSourceRange(); 5003 } 5004 5005 if (DeclRefExpr *DR = dyn_cast<DeclRefExpr>(stackE)) { //address of local var. 5006 S.Diag(diagLoc, lhsType->isReferenceType() ? diag::warn_ret_stack_ref 5007 : diag::warn_ret_stack_addr) 5008 << DR->getDecl()->getDeclName() << diagRange; 5009 } else if (isa<BlockExpr>(stackE)) { // local block. 5010 S.Diag(diagLoc, diag::err_ret_local_block) << diagRange; 5011 } else if (isa<AddrLabelExpr>(stackE)) { // address of label. 5012 S.Diag(diagLoc, diag::warn_ret_addr_label) << diagRange; 5013 } else { // local temporary. 5014 S.Diag(diagLoc, lhsType->isReferenceType() ? diag::warn_ret_local_temp_ref 5015 : diag::warn_ret_local_temp_addr) 5016 << diagRange; 5017 } 5018 5019 // Display the "trail" of reference variables that we followed until we 5020 // found the problematic expression using notes. 5021 for (unsigned i = 0, e = refVars.size(); i != e; ++i) { 5022 VarDecl *VD = cast<VarDecl>(refVars[i]->getDecl()); 5023 // If this var binds to another reference var, show the range of the next 5024 // var, otherwise the var binds to the problematic expression, in which case 5025 // show the range of the expression. 5026 SourceRange range = (i < e-1) ? refVars[i+1]->getSourceRange() 5027 : stackE->getSourceRange(); 5028 S.Diag(VD->getLocation(), diag::note_ref_var_local_bind) 5029 << VD->getDeclName() << range; 5030 } 5031 } 5032 5033 /// EvalAddr - EvalAddr and EvalVal are mutually recursive functions that 5034 /// check if the expression in a return statement evaluates to an address 5035 /// to a location on the stack, a local block, an address of a label, or a 5036 /// reference to local temporary. The recursion is used to traverse the 5037 /// AST of the return expression, with recursion backtracking when we 5038 /// encounter a subexpression that (1) clearly does not lead to one of the 5039 /// above problematic expressions (2) is something we cannot determine leads to 5040 /// a problematic expression based on such local checking. 5041 /// 5042 /// Both EvalAddr and EvalVal follow through reference variables to evaluate 5043 /// the expression that they point to. Such variables are added to the 5044 /// 'refVars' vector so that we know what the reference variable "trail" was. 5045 /// 5046 /// EvalAddr processes expressions that are pointers that are used as 5047 /// references (and not L-values). EvalVal handles all other values. 5048 /// At the base case of the recursion is a check for the above problematic 5049 /// expressions. 5050 /// 5051 /// This implementation handles: 5052 /// 5053 /// * pointer-to-pointer casts 5054 /// * implicit conversions from array references to pointers 5055 /// * taking the address of fields 5056 /// * arbitrary interplay between "&" and "*" operators 5057 /// * pointer arithmetic from an address of a stack variable 5058 /// * taking the address of an array element where the array is on the stack 5059 static Expr *EvalAddr(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars, 5060 Decl *ParentDecl) { 5061 if (E->isTypeDependent()) 5062 return nullptr; 5063 5064 // We should only be called for evaluating pointer expressions. 5065 assert((E->getType()->isAnyPointerType() || 5066 E->getType()->isBlockPointerType() || 5067 E->getType()->isObjCQualifiedIdType()) && 5068 "EvalAddr only works on pointers"); 5069 5070 E = E->IgnoreParens(); 5071 5072 // Our "symbolic interpreter" is just a dispatch off the currently 5073 // viewed AST node. We then recursively traverse the AST by calling 5074 // EvalAddr and EvalVal appropriately. 5075 switch (E->getStmtClass()) { 5076 case Stmt::DeclRefExprClass: { 5077 DeclRefExpr *DR = cast<DeclRefExpr>(E); 5078 5079 // If we leave the immediate function, the lifetime isn't about to end. 5080 if (DR->refersToEnclosingVariableOrCapture()) 5081 return nullptr; 5082 5083 if (VarDecl *V = dyn_cast<VarDecl>(DR->getDecl())) 5084 // If this is a reference variable, follow through to the expression that 5085 // it points to. 5086 if (V->hasLocalStorage() && 5087 V->getType()->isReferenceType() && V->hasInit()) { 5088 // Add the reference variable to the "trail". 5089 refVars.push_back(DR); 5090 return EvalAddr(V->getInit(), refVars, ParentDecl); 5091 } 5092 5093 return nullptr; 5094 } 5095 5096 case Stmt::UnaryOperatorClass: { 5097 // The only unary operator that make sense to handle here 5098 // is AddrOf. All others don't make sense as pointers. 5099 UnaryOperator *U = cast<UnaryOperator>(E); 5100 5101 if (U->getOpcode() == UO_AddrOf) 5102 return EvalVal(U->getSubExpr(), refVars, ParentDecl); 5103 else 5104 return nullptr; 5105 } 5106 5107 case Stmt::BinaryOperatorClass: { 5108 // Handle pointer arithmetic. All other binary operators are not valid 5109 // in this context. 5110 BinaryOperator *B = cast<BinaryOperator>(E); 5111 BinaryOperatorKind op = B->getOpcode(); 5112 5113 if (op != BO_Add && op != BO_Sub) 5114 return nullptr; 5115 5116 Expr *Base = B->getLHS(); 5117 5118 // Determine which argument is the real pointer base. It could be 5119 // the RHS argument instead of the LHS. 5120 if (!Base->getType()->isPointerType()) Base = B->getRHS(); 5121 5122 assert (Base->getType()->isPointerType()); 5123 return EvalAddr(Base, refVars, ParentDecl); 5124 } 5125 5126 // For conditional operators we need to see if either the LHS or RHS are 5127 // valid DeclRefExpr*s. If one of them is valid, we return it. 5128 case Stmt::ConditionalOperatorClass: { 5129 ConditionalOperator *C = cast<ConditionalOperator>(E); 5130 5131 // Handle the GNU extension for missing LHS. 5132 // FIXME: That isn't a ConditionalOperator, so doesn't get here. 5133 if (Expr *LHSExpr = C->getLHS()) { 5134 // In C++, we can have a throw-expression, which has 'void' type. 5135 if (!LHSExpr->getType()->isVoidType()) 5136 if (Expr *LHS = EvalAddr(LHSExpr, refVars, ParentDecl)) 5137 return LHS; 5138 } 5139 5140 // In C++, we can have a throw-expression, which has 'void' type. 5141 if (C->getRHS()->getType()->isVoidType()) 5142 return nullptr; 5143 5144 return EvalAddr(C->getRHS(), refVars, ParentDecl); 5145 } 5146 5147 case Stmt::BlockExprClass: 5148 if (cast<BlockExpr>(E)->getBlockDecl()->hasCaptures()) 5149 return E; // local block. 5150 return nullptr; 5151 5152 case Stmt::AddrLabelExprClass: 5153 return E; // address of label. 5154 5155 case Stmt::ExprWithCleanupsClass: 5156 return EvalAddr(cast<ExprWithCleanups>(E)->getSubExpr(), refVars, 5157 ParentDecl); 5158 5159 // For casts, we need to handle conversions from arrays to 5160 // pointer values, and pointer-to-pointer conversions. 5161 case Stmt::ImplicitCastExprClass: 5162 case Stmt::CStyleCastExprClass: 5163 case Stmt::CXXFunctionalCastExprClass: 5164 case Stmt::ObjCBridgedCastExprClass: 5165 case Stmt::CXXStaticCastExprClass: 5166 case Stmt::CXXDynamicCastExprClass: 5167 case Stmt::CXXConstCastExprClass: 5168 case Stmt::CXXReinterpretCastExprClass: { 5169 Expr* SubExpr = cast<CastExpr>(E)->getSubExpr(); 5170 switch (cast<CastExpr>(E)->getCastKind()) { 5171 case CK_LValueToRValue: 5172 case CK_NoOp: 5173 case CK_BaseToDerived: 5174 case CK_DerivedToBase: 5175 case CK_UncheckedDerivedToBase: 5176 case CK_Dynamic: 5177 case CK_CPointerToObjCPointerCast: 5178 case CK_BlockPointerToObjCPointerCast: 5179 case CK_AnyPointerToBlockPointerCast: 5180 return EvalAddr(SubExpr, refVars, ParentDecl); 5181 5182 case CK_ArrayToPointerDecay: 5183 return EvalVal(SubExpr, refVars, ParentDecl); 5184 5185 case CK_BitCast: 5186 if (SubExpr->getType()->isAnyPointerType() || 5187 SubExpr->getType()->isBlockPointerType() || 5188 SubExpr->getType()->isObjCQualifiedIdType()) 5189 return EvalAddr(SubExpr, refVars, ParentDecl); 5190 else 5191 return nullptr; 5192 5193 default: 5194 return nullptr; 5195 } 5196 } 5197 5198 case Stmt::MaterializeTemporaryExprClass: 5199 if (Expr *Result = EvalAddr( 5200 cast<MaterializeTemporaryExpr>(E)->GetTemporaryExpr(), 5201 refVars, ParentDecl)) 5202 return Result; 5203 5204 return E; 5205 5206 // Everything else: we simply don't reason about them. 5207 default: 5208 return nullptr; 5209 } 5210 } 5211 5212 5213 /// EvalVal - This function is complements EvalAddr in the mutual recursion. 5214 /// See the comments for EvalAddr for more details. 5215 static Expr *EvalVal(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars, 5216 Decl *ParentDecl) { 5217 do { 5218 // We should only be called for evaluating non-pointer expressions, or 5219 // expressions with a pointer type that are not used as references but instead 5220 // are l-values (e.g., DeclRefExpr with a pointer type). 5221 5222 // Our "symbolic interpreter" is just a dispatch off the currently 5223 // viewed AST node. We then recursively traverse the AST by calling 5224 // EvalAddr and EvalVal appropriately. 5225 5226 E = E->IgnoreParens(); 5227 switch (E->getStmtClass()) { 5228 case Stmt::ImplicitCastExprClass: { 5229 ImplicitCastExpr *IE = cast<ImplicitCastExpr>(E); 5230 if (IE->getValueKind() == VK_LValue) { 5231 E = IE->getSubExpr(); 5232 continue; 5233 } 5234 return nullptr; 5235 } 5236 5237 case Stmt::ExprWithCleanupsClass: 5238 return EvalVal(cast<ExprWithCleanups>(E)->getSubExpr(), refVars,ParentDecl); 5239 5240 case Stmt::DeclRefExprClass: { 5241 // When we hit a DeclRefExpr we are looking at code that refers to a 5242 // variable's name. If it's not a reference variable we check if it has 5243 // local storage within the function, and if so, return the expression. 5244 DeclRefExpr *DR = cast<DeclRefExpr>(E); 5245 5246 // If we leave the immediate function, the lifetime isn't about to end. 5247 if (DR->refersToEnclosingVariableOrCapture()) 5248 return nullptr; 5249 5250 if (VarDecl *V = dyn_cast<VarDecl>(DR->getDecl())) { 5251 // Check if it refers to itself, e.g. "int& i = i;". 5252 if (V == ParentDecl) 5253 return DR; 5254 5255 if (V->hasLocalStorage()) { 5256 if (!V->getType()->isReferenceType()) 5257 return DR; 5258 5259 // Reference variable, follow through to the expression that 5260 // it points to. 5261 if (V->hasInit()) { 5262 // Add the reference variable to the "trail". 5263 refVars.push_back(DR); 5264 return EvalVal(V->getInit(), refVars, V); 5265 } 5266 } 5267 } 5268 5269 return nullptr; 5270 } 5271 5272 case Stmt::UnaryOperatorClass: { 5273 // The only unary operator that make sense to handle here 5274 // is Deref. All others don't resolve to a "name." This includes 5275 // handling all sorts of rvalues passed to a unary operator. 5276 UnaryOperator *U = cast<UnaryOperator>(E); 5277 5278 if (U->getOpcode() == UO_Deref) 5279 return EvalAddr(U->getSubExpr(), refVars, ParentDecl); 5280 5281 return nullptr; 5282 } 5283 5284 case Stmt::ArraySubscriptExprClass: { 5285 // Array subscripts are potential references to data on the stack. We 5286 // retrieve the DeclRefExpr* for the array variable if it indeed 5287 // has local storage. 5288 return EvalAddr(cast<ArraySubscriptExpr>(E)->getBase(), refVars,ParentDecl); 5289 } 5290 5291 case Stmt::ConditionalOperatorClass: { 5292 // For conditional operators we need to see if either the LHS or RHS are 5293 // non-NULL Expr's. If one is non-NULL, we return it. 5294 ConditionalOperator *C = cast<ConditionalOperator>(E); 5295 5296 // Handle the GNU extension for missing LHS. 5297 if (Expr *LHSExpr = C->getLHS()) { 5298 // In C++, we can have a throw-expression, which has 'void' type. 5299 if (!LHSExpr->getType()->isVoidType()) 5300 if (Expr *LHS = EvalVal(LHSExpr, refVars, ParentDecl)) 5301 return LHS; 5302 } 5303 5304 // In C++, we can have a throw-expression, which has 'void' type. 5305 if (C->getRHS()->getType()->isVoidType()) 5306 return nullptr; 5307 5308 return EvalVal(C->getRHS(), refVars, ParentDecl); 5309 } 5310 5311 // Accesses to members are potential references to data on the stack. 5312 case Stmt::MemberExprClass: { 5313 MemberExpr *M = cast<MemberExpr>(E); 5314 5315 // Check for indirect access. We only want direct field accesses. 5316 if (M->isArrow()) 5317 return nullptr; 5318 5319 // Check whether the member type is itself a reference, in which case 5320 // we're not going to refer to the member, but to what the member refers to. 5321 if (M->getMemberDecl()->getType()->isReferenceType()) 5322 return nullptr; 5323 5324 return EvalVal(M->getBase(), refVars, ParentDecl); 5325 } 5326 5327 case Stmt::MaterializeTemporaryExprClass: 5328 if (Expr *Result = EvalVal( 5329 cast<MaterializeTemporaryExpr>(E)->GetTemporaryExpr(), 5330 refVars, ParentDecl)) 5331 return Result; 5332 5333 return E; 5334 5335 default: 5336 // Check that we don't return or take the address of a reference to a 5337 // temporary. This is only useful in C++. 5338 if (!E->isTypeDependent() && E->isRValue()) 5339 return E; 5340 5341 // Everything else: we simply don't reason about them. 5342 return nullptr; 5343 } 5344 } while (true); 5345 } 5346 5347 void 5348 Sema::CheckReturnValExpr(Expr *RetValExp, QualType lhsType, 5349 SourceLocation ReturnLoc, 5350 bool isObjCMethod, 5351 const AttrVec *Attrs, 5352 const FunctionDecl *FD) { 5353 CheckReturnStackAddr(*this, RetValExp, lhsType, ReturnLoc); 5354 5355 // Check if the return value is null but should not be. 5356 if (Attrs && hasSpecificAttr<ReturnsNonNullAttr>(*Attrs) && 5357 CheckNonNullExpr(*this, RetValExp)) 5358 Diag(ReturnLoc, diag::warn_null_ret) 5359 << (isObjCMethod ? 1 : 0) << RetValExp->getSourceRange(); 5360 5361 // C++11 [basic.stc.dynamic.allocation]p4: 5362 // If an allocation function declared with a non-throwing 5363 // exception-specification fails to allocate storage, it shall return 5364 // a null pointer. Any other allocation function that fails to allocate 5365 // storage shall indicate failure only by throwing an exception [...] 5366 if (FD) { 5367 OverloadedOperatorKind Op = FD->getOverloadedOperator(); 5368 if (Op == OO_New || Op == OO_Array_New) { 5369 const FunctionProtoType *Proto 5370 = FD->getType()->castAs<FunctionProtoType>(); 5371 if (!Proto->isNothrow(Context, /*ResultIfDependent*/true) && 5372 CheckNonNullExpr(*this, RetValExp)) 5373 Diag(ReturnLoc, diag::warn_operator_new_returns_null) 5374 << FD << getLangOpts().CPlusPlus11; 5375 } 5376 } 5377 } 5378 5379 //===--- CHECK: Floating-Point comparisons (-Wfloat-equal) ---------------===// 5380 5381 /// Check for comparisons of floating point operands using != and ==. 5382 /// Issue a warning if these are no self-comparisons, as they are not likely 5383 /// to do what the programmer intended. 5384 void Sema::CheckFloatComparison(SourceLocation Loc, Expr* LHS, Expr *RHS) { 5385 Expr* LeftExprSansParen = LHS->IgnoreParenImpCasts(); 5386 Expr* RightExprSansParen = RHS->IgnoreParenImpCasts(); 5387 5388 // Special case: check for x == x (which is OK). 5389 // Do not emit warnings for such cases. 5390 if (DeclRefExpr* DRL = dyn_cast<DeclRefExpr>(LeftExprSansParen)) 5391 if (DeclRefExpr* DRR = dyn_cast<DeclRefExpr>(RightExprSansParen)) 5392 if (DRL->getDecl() == DRR->getDecl()) 5393 return; 5394 5395 5396 // Special case: check for comparisons against literals that can be exactly 5397 // represented by APFloat. In such cases, do not emit a warning. This 5398 // is a heuristic: often comparison against such literals are used to 5399 // detect if a value in a variable has not changed. This clearly can 5400 // lead to false negatives. 5401 if (FloatingLiteral* FLL = dyn_cast<FloatingLiteral>(LeftExprSansParen)) { 5402 if (FLL->isExact()) 5403 return; 5404 } else 5405 if (FloatingLiteral* FLR = dyn_cast<FloatingLiteral>(RightExprSansParen)) 5406 if (FLR->isExact()) 5407 return; 5408 5409 // Check for comparisons with builtin types. 5410 if (CallExpr* CL = dyn_cast<CallExpr>(LeftExprSansParen)) 5411 if (CL->getBuiltinCallee()) 5412 return; 5413 5414 if (CallExpr* CR = dyn_cast<CallExpr>(RightExprSansParen)) 5415 if (CR->getBuiltinCallee()) 5416 return; 5417 5418 // Emit the diagnostic. 5419 Diag(Loc, diag::warn_floatingpoint_eq) 5420 << LHS->getSourceRange() << RHS->getSourceRange(); 5421 } 5422 5423 //===--- CHECK: Integer mixed-sign comparisons (-Wsign-compare) --------===// 5424 //===--- CHECK: Lossy implicit conversions (-Wconversion) --------------===// 5425 5426 namespace { 5427 5428 /// Structure recording the 'active' range of an integer-valued 5429 /// expression. 5430 struct IntRange { 5431 /// The number of bits active in the int. 5432 unsigned Width; 5433 5434 /// True if the int is known not to have negative values. 5435 bool NonNegative; 5436 5437 IntRange(unsigned Width, bool NonNegative) 5438 : Width(Width), NonNegative(NonNegative) 5439 {} 5440 5441 /// Returns the range of the bool type. 5442 static IntRange forBoolType() { 5443 return IntRange(1, true); 5444 } 5445 5446 /// Returns the range of an opaque value of the given integral type. 5447 static IntRange forValueOfType(ASTContext &C, QualType T) { 5448 return forValueOfCanonicalType(C, 5449 T->getCanonicalTypeInternal().getTypePtr()); 5450 } 5451 5452 /// Returns the range of an opaque value of a canonical integral type. 5453 static IntRange forValueOfCanonicalType(ASTContext &C, const Type *T) { 5454 assert(T->isCanonicalUnqualified()); 5455 5456 if (const VectorType *VT = dyn_cast<VectorType>(T)) 5457 T = VT->getElementType().getTypePtr(); 5458 if (const ComplexType *CT = dyn_cast<ComplexType>(T)) 5459 T = CT->getElementType().getTypePtr(); 5460 if (const AtomicType *AT = dyn_cast<AtomicType>(T)) 5461 T = AT->getValueType().getTypePtr(); 5462 5463 // For enum types, use the known bit width of the enumerators. 5464 if (const EnumType *ET = dyn_cast<EnumType>(T)) { 5465 EnumDecl *Enum = ET->getDecl(); 5466 if (!Enum->isCompleteDefinition()) 5467 return IntRange(C.getIntWidth(QualType(T, 0)), false); 5468 5469 unsigned NumPositive = Enum->getNumPositiveBits(); 5470 unsigned NumNegative = Enum->getNumNegativeBits(); 5471 5472 if (NumNegative == 0) 5473 return IntRange(NumPositive, true/*NonNegative*/); 5474 else 5475 return IntRange(std::max(NumPositive + 1, NumNegative), 5476 false/*NonNegative*/); 5477 } 5478 5479 const BuiltinType *BT = cast<BuiltinType>(T); 5480 assert(BT->isInteger()); 5481 5482 return IntRange(C.getIntWidth(QualType(T, 0)), BT->isUnsignedInteger()); 5483 } 5484 5485 /// Returns the "target" range of a canonical integral type, i.e. 5486 /// the range of values expressible in the type. 5487 /// 5488 /// This matches forValueOfCanonicalType except that enums have the 5489 /// full range of their type, not the range of their enumerators. 5490 static IntRange forTargetOfCanonicalType(ASTContext &C, const Type *T) { 5491 assert(T->isCanonicalUnqualified()); 5492 5493 if (const VectorType *VT = dyn_cast<VectorType>(T)) 5494 T = VT->getElementType().getTypePtr(); 5495 if (const ComplexType *CT = dyn_cast<ComplexType>(T)) 5496 T = CT->getElementType().getTypePtr(); 5497 if (const AtomicType *AT = dyn_cast<AtomicType>(T)) 5498 T = AT->getValueType().getTypePtr(); 5499 if (const EnumType *ET = dyn_cast<EnumType>(T)) 5500 T = C.getCanonicalType(ET->getDecl()->getIntegerType()).getTypePtr(); 5501 5502 const BuiltinType *BT = cast<BuiltinType>(T); 5503 assert(BT->isInteger()); 5504 5505 return IntRange(C.getIntWidth(QualType(T, 0)), BT->isUnsignedInteger()); 5506 } 5507 5508 /// Returns the supremum of two ranges: i.e. their conservative merge. 5509 static IntRange join(IntRange L, IntRange R) { 5510 return IntRange(std::max(L.Width, R.Width), 5511 L.NonNegative && R.NonNegative); 5512 } 5513 5514 /// Returns the infinum of two ranges: i.e. their aggressive merge. 5515 static IntRange meet(IntRange L, IntRange R) { 5516 return IntRange(std::min(L.Width, R.Width), 5517 L.NonNegative || R.NonNegative); 5518 } 5519 }; 5520 5521 static IntRange GetValueRange(ASTContext &C, llvm::APSInt &value, 5522 unsigned MaxWidth) { 5523 if (value.isSigned() && value.isNegative()) 5524 return IntRange(value.getMinSignedBits(), false); 5525 5526 if (value.getBitWidth() > MaxWidth) 5527 value = value.trunc(MaxWidth); 5528 5529 // isNonNegative() just checks the sign bit without considering 5530 // signedness. 5531 return IntRange(value.getActiveBits(), true); 5532 } 5533 5534 static IntRange GetValueRange(ASTContext &C, APValue &result, QualType Ty, 5535 unsigned MaxWidth) { 5536 if (result.isInt()) 5537 return GetValueRange(C, result.getInt(), MaxWidth); 5538 5539 if (result.isVector()) { 5540 IntRange R = GetValueRange(C, result.getVectorElt(0), Ty, MaxWidth); 5541 for (unsigned i = 1, e = result.getVectorLength(); i != e; ++i) { 5542 IntRange El = GetValueRange(C, result.getVectorElt(i), Ty, MaxWidth); 5543 R = IntRange::join(R, El); 5544 } 5545 return R; 5546 } 5547 5548 if (result.isComplexInt()) { 5549 IntRange R = GetValueRange(C, result.getComplexIntReal(), MaxWidth); 5550 IntRange I = GetValueRange(C, result.getComplexIntImag(), MaxWidth); 5551 return IntRange::join(R, I); 5552 } 5553 5554 // This can happen with lossless casts to intptr_t of "based" lvalues. 5555 // Assume it might use arbitrary bits. 5556 // FIXME: The only reason we need to pass the type in here is to get 5557 // the sign right on this one case. It would be nice if APValue 5558 // preserved this. 5559 assert(result.isLValue() || result.isAddrLabelDiff()); 5560 return IntRange(MaxWidth, Ty->isUnsignedIntegerOrEnumerationType()); 5561 } 5562 5563 static QualType GetExprType(Expr *E) { 5564 QualType Ty = E->getType(); 5565 if (const AtomicType *AtomicRHS = Ty->getAs<AtomicType>()) 5566 Ty = AtomicRHS->getValueType(); 5567 return Ty; 5568 } 5569 5570 /// Pseudo-evaluate the given integer expression, estimating the 5571 /// range of values it might take. 5572 /// 5573 /// \param MaxWidth - the width to which the value will be truncated 5574 static IntRange GetExprRange(ASTContext &C, Expr *E, unsigned MaxWidth) { 5575 E = E->IgnoreParens(); 5576 5577 // Try a full evaluation first. 5578 Expr::EvalResult result; 5579 if (E->EvaluateAsRValue(result, C)) 5580 return GetValueRange(C, result.Val, GetExprType(E), MaxWidth); 5581 5582 // I think we only want to look through implicit casts here; if the 5583 // user has an explicit widening cast, we should treat the value as 5584 // being of the new, wider type. 5585 if (ImplicitCastExpr *CE = dyn_cast<ImplicitCastExpr>(E)) { 5586 if (CE->getCastKind() == CK_NoOp || CE->getCastKind() == CK_LValueToRValue) 5587 return GetExprRange(C, CE->getSubExpr(), MaxWidth); 5588 5589 IntRange OutputTypeRange = IntRange::forValueOfType(C, GetExprType(CE)); 5590 5591 bool isIntegerCast = (CE->getCastKind() == CK_IntegralCast); 5592 5593 // Assume that non-integer casts can span the full range of the type. 5594 if (!isIntegerCast) 5595 return OutputTypeRange; 5596 5597 IntRange SubRange 5598 = GetExprRange(C, CE->getSubExpr(), 5599 std::min(MaxWidth, OutputTypeRange.Width)); 5600 5601 // Bail out if the subexpr's range is as wide as the cast type. 5602 if (SubRange.Width >= OutputTypeRange.Width) 5603 return OutputTypeRange; 5604 5605 // Otherwise, we take the smaller width, and we're non-negative if 5606 // either the output type or the subexpr is. 5607 return IntRange(SubRange.Width, 5608 SubRange.NonNegative || OutputTypeRange.NonNegative); 5609 } 5610 5611 if (ConditionalOperator *CO = dyn_cast<ConditionalOperator>(E)) { 5612 // If we can fold the condition, just take that operand. 5613 bool CondResult; 5614 if (CO->getCond()->EvaluateAsBooleanCondition(CondResult, C)) 5615 return GetExprRange(C, CondResult ? CO->getTrueExpr() 5616 : CO->getFalseExpr(), 5617 MaxWidth); 5618 5619 // Otherwise, conservatively merge. 5620 IntRange L = GetExprRange(C, CO->getTrueExpr(), MaxWidth); 5621 IntRange R = GetExprRange(C, CO->getFalseExpr(), MaxWidth); 5622 return IntRange::join(L, R); 5623 } 5624 5625 if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) { 5626 switch (BO->getOpcode()) { 5627 5628 // Boolean-valued operations are single-bit and positive. 5629 case BO_LAnd: 5630 case BO_LOr: 5631 case BO_LT: 5632 case BO_GT: 5633 case BO_LE: 5634 case BO_GE: 5635 case BO_EQ: 5636 case BO_NE: 5637 return IntRange::forBoolType(); 5638 5639 // The type of the assignments is the type of the LHS, so the RHS 5640 // is not necessarily the same type. 5641 case BO_MulAssign: 5642 case BO_DivAssign: 5643 case BO_RemAssign: 5644 case BO_AddAssign: 5645 case BO_SubAssign: 5646 case BO_XorAssign: 5647 case BO_OrAssign: 5648 // TODO: bitfields? 5649 return IntRange::forValueOfType(C, GetExprType(E)); 5650 5651 // Simple assignments just pass through the RHS, which will have 5652 // been coerced to the LHS type. 5653 case BO_Assign: 5654 // TODO: bitfields? 5655 return GetExprRange(C, BO->getRHS(), MaxWidth); 5656 5657 // Operations with opaque sources are black-listed. 5658 case BO_PtrMemD: 5659 case BO_PtrMemI: 5660 return IntRange::forValueOfType(C, GetExprType(E)); 5661 5662 // Bitwise-and uses the *infinum* of the two source ranges. 5663 case BO_And: 5664 case BO_AndAssign: 5665 return IntRange::meet(GetExprRange(C, BO->getLHS(), MaxWidth), 5666 GetExprRange(C, BO->getRHS(), MaxWidth)); 5667 5668 // Left shift gets black-listed based on a judgement call. 5669 case BO_Shl: 5670 // ...except that we want to treat '1 << (blah)' as logically 5671 // positive. It's an important idiom. 5672 if (IntegerLiteral *I 5673 = dyn_cast<IntegerLiteral>(BO->getLHS()->IgnoreParenCasts())) { 5674 if (I->getValue() == 1) { 5675 IntRange R = IntRange::forValueOfType(C, GetExprType(E)); 5676 return IntRange(R.Width, /*NonNegative*/ true); 5677 } 5678 } 5679 // fallthrough 5680 5681 case BO_ShlAssign: 5682 return IntRange::forValueOfType(C, GetExprType(E)); 5683 5684 // Right shift by a constant can narrow its left argument. 5685 case BO_Shr: 5686 case BO_ShrAssign: { 5687 IntRange L = GetExprRange(C, BO->getLHS(), MaxWidth); 5688 5689 // If the shift amount is a positive constant, drop the width by 5690 // that much. 5691 llvm::APSInt shift; 5692 if (BO->getRHS()->isIntegerConstantExpr(shift, C) && 5693 shift.isNonNegative()) { 5694 unsigned zext = shift.getZExtValue(); 5695 if (zext >= L.Width) 5696 L.Width = (L.NonNegative ? 0 : 1); 5697 else 5698 L.Width -= zext; 5699 } 5700 5701 return L; 5702 } 5703 5704 // Comma acts as its right operand. 5705 case BO_Comma: 5706 return GetExprRange(C, BO->getRHS(), MaxWidth); 5707 5708 // Black-list pointer subtractions. 5709 case BO_Sub: 5710 if (BO->getLHS()->getType()->isPointerType()) 5711 return IntRange::forValueOfType(C, GetExprType(E)); 5712 break; 5713 5714 // The width of a division result is mostly determined by the size 5715 // of the LHS. 5716 case BO_Div: { 5717 // Don't 'pre-truncate' the operands. 5718 unsigned opWidth = C.getIntWidth(GetExprType(E)); 5719 IntRange L = GetExprRange(C, BO->getLHS(), opWidth); 5720 5721 // If the divisor is constant, use that. 5722 llvm::APSInt divisor; 5723 if (BO->getRHS()->isIntegerConstantExpr(divisor, C)) { 5724 unsigned log2 = divisor.logBase2(); // floor(log_2(divisor)) 5725 if (log2 >= L.Width) 5726 L.Width = (L.NonNegative ? 0 : 1); 5727 else 5728 L.Width = std::min(L.Width - log2, MaxWidth); 5729 return L; 5730 } 5731 5732 // Otherwise, just use the LHS's width. 5733 IntRange R = GetExprRange(C, BO->getRHS(), opWidth); 5734 return IntRange(L.Width, L.NonNegative && R.NonNegative); 5735 } 5736 5737 // The result of a remainder can't be larger than the result of 5738 // either side. 5739 case BO_Rem: { 5740 // Don't 'pre-truncate' the operands. 5741 unsigned opWidth = C.getIntWidth(GetExprType(E)); 5742 IntRange L = GetExprRange(C, BO->getLHS(), opWidth); 5743 IntRange R = GetExprRange(C, BO->getRHS(), opWidth); 5744 5745 IntRange meet = IntRange::meet(L, R); 5746 meet.Width = std::min(meet.Width, MaxWidth); 5747 return meet; 5748 } 5749 5750 // The default behavior is okay for these. 5751 case BO_Mul: 5752 case BO_Add: 5753 case BO_Xor: 5754 case BO_Or: 5755 break; 5756 } 5757 5758 // The default case is to treat the operation as if it were closed 5759 // on the narrowest type that encompasses both operands. 5760 IntRange L = GetExprRange(C, BO->getLHS(), MaxWidth); 5761 IntRange R = GetExprRange(C, BO->getRHS(), MaxWidth); 5762 return IntRange::join(L, R); 5763 } 5764 5765 if (UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) { 5766 switch (UO->getOpcode()) { 5767 // Boolean-valued operations are white-listed. 5768 case UO_LNot: 5769 return IntRange::forBoolType(); 5770 5771 // Operations with opaque sources are black-listed. 5772 case UO_Deref: 5773 case UO_AddrOf: // should be impossible 5774 return IntRange::forValueOfType(C, GetExprType(E)); 5775 5776 default: 5777 return GetExprRange(C, UO->getSubExpr(), MaxWidth); 5778 } 5779 } 5780 5781 if (OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(E)) 5782 return GetExprRange(C, OVE->getSourceExpr(), MaxWidth); 5783 5784 if (FieldDecl *BitField = E->getSourceBitField()) 5785 return IntRange(BitField->getBitWidthValue(C), 5786 BitField->getType()->isUnsignedIntegerOrEnumerationType()); 5787 5788 return IntRange::forValueOfType(C, GetExprType(E)); 5789 } 5790 5791 static IntRange GetExprRange(ASTContext &C, Expr *E) { 5792 return GetExprRange(C, E, C.getIntWidth(GetExprType(E))); 5793 } 5794 5795 /// Checks whether the given value, which currently has the given 5796 /// source semantics, has the same value when coerced through the 5797 /// target semantics. 5798 static bool IsSameFloatAfterCast(const llvm::APFloat &value, 5799 const llvm::fltSemantics &Src, 5800 const llvm::fltSemantics &Tgt) { 5801 llvm::APFloat truncated = value; 5802 5803 bool ignored; 5804 truncated.convert(Src, llvm::APFloat::rmNearestTiesToEven, &ignored); 5805 truncated.convert(Tgt, llvm::APFloat::rmNearestTiesToEven, &ignored); 5806 5807 return truncated.bitwiseIsEqual(value); 5808 } 5809 5810 /// Checks whether the given value, which currently has the given 5811 /// source semantics, has the same value when coerced through the 5812 /// target semantics. 5813 /// 5814 /// The value might be a vector of floats (or a complex number). 5815 static bool IsSameFloatAfterCast(const APValue &value, 5816 const llvm::fltSemantics &Src, 5817 const llvm::fltSemantics &Tgt) { 5818 if (value.isFloat()) 5819 return IsSameFloatAfterCast(value.getFloat(), Src, Tgt); 5820 5821 if (value.isVector()) { 5822 for (unsigned i = 0, e = value.getVectorLength(); i != e; ++i) 5823 if (!IsSameFloatAfterCast(value.getVectorElt(i), Src, Tgt)) 5824 return false; 5825 return true; 5826 } 5827 5828 assert(value.isComplexFloat()); 5829 return (IsSameFloatAfterCast(value.getComplexFloatReal(), Src, Tgt) && 5830 IsSameFloatAfterCast(value.getComplexFloatImag(), Src, Tgt)); 5831 } 5832 5833 static void AnalyzeImplicitConversions(Sema &S, Expr *E, SourceLocation CC); 5834 5835 static bool IsZero(Sema &S, Expr *E) { 5836 // Suppress cases where we are comparing against an enum constant. 5837 if (const DeclRefExpr *DR = 5838 dyn_cast<DeclRefExpr>(E->IgnoreParenImpCasts())) 5839 if (isa<EnumConstantDecl>(DR->getDecl())) 5840 return false; 5841 5842 // Suppress cases where the '0' value is expanded from a macro. 5843 if (E->getLocStart().isMacroID()) 5844 return false; 5845 5846 llvm::APSInt Value; 5847 return E->isIntegerConstantExpr(Value, S.Context) && Value == 0; 5848 } 5849 5850 static bool HasEnumType(Expr *E) { 5851 // Strip off implicit integral promotions. 5852 while (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) { 5853 if (ICE->getCastKind() != CK_IntegralCast && 5854 ICE->getCastKind() != CK_NoOp) 5855 break; 5856 E = ICE->getSubExpr(); 5857 } 5858 5859 return E->getType()->isEnumeralType(); 5860 } 5861 5862 static void CheckTrivialUnsignedComparison(Sema &S, BinaryOperator *E) { 5863 // Disable warning in template instantiations. 5864 if (!S.ActiveTemplateInstantiations.empty()) 5865 return; 5866 5867 BinaryOperatorKind op = E->getOpcode(); 5868 if (E->isValueDependent()) 5869 return; 5870 5871 if (op == BO_LT && IsZero(S, E->getRHS())) { 5872 S.Diag(E->getOperatorLoc(), diag::warn_lunsigned_always_true_comparison) 5873 << "< 0" << "false" << HasEnumType(E->getLHS()) 5874 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); 5875 } else if (op == BO_GE && IsZero(S, E->getRHS())) { 5876 S.Diag(E->getOperatorLoc(), diag::warn_lunsigned_always_true_comparison) 5877 << ">= 0" << "true" << HasEnumType(E->getLHS()) 5878 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); 5879 } else if (op == BO_GT && IsZero(S, E->getLHS())) { 5880 S.Diag(E->getOperatorLoc(), diag::warn_runsigned_always_true_comparison) 5881 << "0 >" << "false" << HasEnumType(E->getRHS()) 5882 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); 5883 } else if (op == BO_LE && IsZero(S, E->getLHS())) { 5884 S.Diag(E->getOperatorLoc(), diag::warn_runsigned_always_true_comparison) 5885 << "0 <=" << "true" << HasEnumType(E->getRHS()) 5886 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); 5887 } 5888 } 5889 5890 static void DiagnoseOutOfRangeComparison(Sema &S, BinaryOperator *E, 5891 Expr *Constant, Expr *Other, 5892 llvm::APSInt Value, 5893 bool RhsConstant) { 5894 // Disable warning in template instantiations. 5895 if (!S.ActiveTemplateInstantiations.empty()) 5896 return; 5897 5898 // TODO: Investigate using GetExprRange() to get tighter bounds 5899 // on the bit ranges. 5900 QualType OtherT = Other->getType(); 5901 if (const AtomicType *AT = dyn_cast<AtomicType>(OtherT)) 5902 OtherT = AT->getValueType(); 5903 IntRange OtherRange = IntRange::forValueOfType(S.Context, OtherT); 5904 unsigned OtherWidth = OtherRange.Width; 5905 5906 bool OtherIsBooleanType = Other->isKnownToHaveBooleanValue(); 5907 5908 // 0 values are handled later by CheckTrivialUnsignedComparison(). 5909 if ((Value == 0) && (!OtherIsBooleanType)) 5910 return; 5911 5912 BinaryOperatorKind op = E->getOpcode(); 5913 bool IsTrue = true; 5914 5915 // Used for diagnostic printout. 5916 enum { 5917 LiteralConstant = 0, 5918 CXXBoolLiteralTrue, 5919 CXXBoolLiteralFalse 5920 } LiteralOrBoolConstant = LiteralConstant; 5921 5922 if (!OtherIsBooleanType) { 5923 QualType ConstantT = Constant->getType(); 5924 QualType CommonT = E->getLHS()->getType(); 5925 5926 if (S.Context.hasSameUnqualifiedType(OtherT, ConstantT)) 5927 return; 5928 assert((OtherT->isIntegerType() && ConstantT->isIntegerType()) && 5929 "comparison with non-integer type"); 5930 5931 bool ConstantSigned = ConstantT->isSignedIntegerType(); 5932 bool CommonSigned = CommonT->isSignedIntegerType(); 5933 5934 bool EqualityOnly = false; 5935 5936 if (CommonSigned) { 5937 // The common type is signed, therefore no signed to unsigned conversion. 5938 if (!OtherRange.NonNegative) { 5939 // Check that the constant is representable in type OtherT. 5940 if (ConstantSigned) { 5941 if (OtherWidth >= Value.getMinSignedBits()) 5942 return; 5943 } else { // !ConstantSigned 5944 if (OtherWidth >= Value.getActiveBits() + 1) 5945 return; 5946 } 5947 } else { // !OtherSigned 5948 // Check that the constant is representable in type OtherT. 5949 // Negative values are out of range. 5950 if (ConstantSigned) { 5951 if (Value.isNonNegative() && OtherWidth >= Value.getActiveBits()) 5952 return; 5953 } else { // !ConstantSigned 5954 if (OtherWidth >= Value.getActiveBits()) 5955 return; 5956 } 5957 } 5958 } else { // !CommonSigned 5959 if (OtherRange.NonNegative) { 5960 if (OtherWidth >= Value.getActiveBits()) 5961 return; 5962 } else { // OtherSigned 5963 assert(!ConstantSigned && 5964 "Two signed types converted to unsigned types."); 5965 // Check to see if the constant is representable in OtherT. 5966 if (OtherWidth > Value.getActiveBits()) 5967 return; 5968 // Check to see if the constant is equivalent to a negative value 5969 // cast to CommonT. 5970 if (S.Context.getIntWidth(ConstantT) == 5971 S.Context.getIntWidth(CommonT) && 5972 Value.isNegative() && Value.getMinSignedBits() <= OtherWidth) 5973 return; 5974 // The constant value rests between values that OtherT can represent 5975 // after conversion. Relational comparison still works, but equality 5976 // comparisons will be tautological. 5977 EqualityOnly = true; 5978 } 5979 } 5980 5981 bool PositiveConstant = !ConstantSigned || Value.isNonNegative(); 5982 5983 if (op == BO_EQ || op == BO_NE) { 5984 IsTrue = op == BO_NE; 5985 } else if (EqualityOnly) { 5986 return; 5987 } else if (RhsConstant) { 5988 if (op == BO_GT || op == BO_GE) 5989 IsTrue = !PositiveConstant; 5990 else // op == BO_LT || op == BO_LE 5991 IsTrue = PositiveConstant; 5992 } else { 5993 if (op == BO_LT || op == BO_LE) 5994 IsTrue = !PositiveConstant; 5995 else // op == BO_GT || op == BO_GE 5996 IsTrue = PositiveConstant; 5997 } 5998 } else { 5999 // Other isKnownToHaveBooleanValue 6000 enum CompareBoolWithConstantResult { AFals, ATrue, Unkwn }; 6001 enum ConstantValue { LT_Zero, Zero, One, GT_One, SizeOfConstVal }; 6002 enum ConstantSide { Lhs, Rhs, SizeOfConstSides }; 6003 6004 static const struct LinkedConditions { 6005 CompareBoolWithConstantResult BO_LT_OP[SizeOfConstSides][SizeOfConstVal]; 6006 CompareBoolWithConstantResult BO_GT_OP[SizeOfConstSides][SizeOfConstVal]; 6007 CompareBoolWithConstantResult BO_LE_OP[SizeOfConstSides][SizeOfConstVal]; 6008 CompareBoolWithConstantResult BO_GE_OP[SizeOfConstSides][SizeOfConstVal]; 6009 CompareBoolWithConstantResult BO_EQ_OP[SizeOfConstSides][SizeOfConstVal]; 6010 CompareBoolWithConstantResult BO_NE_OP[SizeOfConstSides][SizeOfConstVal]; 6011 6012 } TruthTable = { 6013 // Constant on LHS. | Constant on RHS. | 6014 // LT_Zero| Zero | One |GT_One| LT_Zero| Zero | One |GT_One| 6015 { { ATrue, Unkwn, AFals, AFals }, { AFals, AFals, Unkwn, ATrue } }, 6016 { { AFals, AFals, Unkwn, ATrue }, { ATrue, Unkwn, AFals, AFals } }, 6017 { { ATrue, ATrue, Unkwn, AFals }, { AFals, Unkwn, ATrue, ATrue } }, 6018 { { AFals, Unkwn, ATrue, ATrue }, { ATrue, ATrue, Unkwn, AFals } }, 6019 { { AFals, Unkwn, Unkwn, AFals }, { AFals, Unkwn, Unkwn, AFals } }, 6020 { { ATrue, Unkwn, Unkwn, ATrue }, { ATrue, Unkwn, Unkwn, ATrue } } 6021 }; 6022 6023 bool ConstantIsBoolLiteral = isa<CXXBoolLiteralExpr>(Constant); 6024 6025 enum ConstantValue ConstVal = Zero; 6026 if (Value.isUnsigned() || Value.isNonNegative()) { 6027 if (Value == 0) { 6028 LiteralOrBoolConstant = 6029 ConstantIsBoolLiteral ? CXXBoolLiteralFalse : LiteralConstant; 6030 ConstVal = Zero; 6031 } else if (Value == 1) { 6032 LiteralOrBoolConstant = 6033 ConstantIsBoolLiteral ? CXXBoolLiteralTrue : LiteralConstant; 6034 ConstVal = One; 6035 } else { 6036 LiteralOrBoolConstant = LiteralConstant; 6037 ConstVal = GT_One; 6038 } 6039 } else { 6040 ConstVal = LT_Zero; 6041 } 6042 6043 CompareBoolWithConstantResult CmpRes; 6044 6045 switch (op) { 6046 case BO_LT: 6047 CmpRes = TruthTable.BO_LT_OP[RhsConstant][ConstVal]; 6048 break; 6049 case BO_GT: 6050 CmpRes = TruthTable.BO_GT_OP[RhsConstant][ConstVal]; 6051 break; 6052 case BO_LE: 6053 CmpRes = TruthTable.BO_LE_OP[RhsConstant][ConstVal]; 6054 break; 6055 case BO_GE: 6056 CmpRes = TruthTable.BO_GE_OP[RhsConstant][ConstVal]; 6057 break; 6058 case BO_EQ: 6059 CmpRes = TruthTable.BO_EQ_OP[RhsConstant][ConstVal]; 6060 break; 6061 case BO_NE: 6062 CmpRes = TruthTable.BO_NE_OP[RhsConstant][ConstVal]; 6063 break; 6064 default: 6065 CmpRes = Unkwn; 6066 break; 6067 } 6068 6069 if (CmpRes == AFals) { 6070 IsTrue = false; 6071 } else if (CmpRes == ATrue) { 6072 IsTrue = true; 6073 } else { 6074 return; 6075 } 6076 } 6077 6078 // If this is a comparison to an enum constant, include that 6079 // constant in the diagnostic. 6080 const EnumConstantDecl *ED = nullptr; 6081 if (const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(Constant)) 6082 ED = dyn_cast<EnumConstantDecl>(DR->getDecl()); 6083 6084 SmallString<64> PrettySourceValue; 6085 llvm::raw_svector_ostream OS(PrettySourceValue); 6086 if (ED) 6087 OS << '\'' << *ED << "' (" << Value << ")"; 6088 else 6089 OS << Value; 6090 6091 S.DiagRuntimeBehavior( 6092 E->getOperatorLoc(), E, 6093 S.PDiag(diag::warn_out_of_range_compare) 6094 << OS.str() << LiteralOrBoolConstant 6095 << OtherT << (OtherIsBooleanType && !OtherT->isBooleanType()) << IsTrue 6096 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange()); 6097 } 6098 6099 /// Analyze the operands of the given comparison. Implements the 6100 /// fallback case from AnalyzeComparison. 6101 static void AnalyzeImpConvsInComparison(Sema &S, BinaryOperator *E) { 6102 AnalyzeImplicitConversions(S, E->getLHS(), E->getOperatorLoc()); 6103 AnalyzeImplicitConversions(S, E->getRHS(), E->getOperatorLoc()); 6104 } 6105 6106 /// \brief Implements -Wsign-compare. 6107 /// 6108 /// \param E the binary operator to check for warnings 6109 static void AnalyzeComparison(Sema &S, BinaryOperator *E) { 6110 // The type the comparison is being performed in. 6111 QualType T = E->getLHS()->getType(); 6112 6113 // Only analyze comparison operators where both sides have been converted to 6114 // the same type. 6115 if (!S.Context.hasSameUnqualifiedType(T, E->getRHS()->getType())) 6116 return AnalyzeImpConvsInComparison(S, E); 6117 6118 // Don't analyze value-dependent comparisons directly. 6119 if (E->isValueDependent()) 6120 return AnalyzeImpConvsInComparison(S, E); 6121 6122 Expr *LHS = E->getLHS()->IgnoreParenImpCasts(); 6123 Expr *RHS = E->getRHS()->IgnoreParenImpCasts(); 6124 6125 bool IsComparisonConstant = false; 6126 6127 // Check whether an integer constant comparison results in a value 6128 // of 'true' or 'false'. 6129 if (T->isIntegralType(S.Context)) { 6130 llvm::APSInt RHSValue; 6131 bool IsRHSIntegralLiteral = 6132 RHS->isIntegerConstantExpr(RHSValue, S.Context); 6133 llvm::APSInt LHSValue; 6134 bool IsLHSIntegralLiteral = 6135 LHS->isIntegerConstantExpr(LHSValue, S.Context); 6136 if (IsRHSIntegralLiteral && !IsLHSIntegralLiteral) 6137 DiagnoseOutOfRangeComparison(S, E, RHS, LHS, RHSValue, true); 6138 else if (!IsRHSIntegralLiteral && IsLHSIntegralLiteral) 6139 DiagnoseOutOfRangeComparison(S, E, LHS, RHS, LHSValue, false); 6140 else 6141 IsComparisonConstant = 6142 (IsRHSIntegralLiteral && IsLHSIntegralLiteral); 6143 } else if (!T->hasUnsignedIntegerRepresentation()) 6144 IsComparisonConstant = E->isIntegerConstantExpr(S.Context); 6145 6146 // We don't do anything special if this isn't an unsigned integral 6147 // comparison: we're only interested in integral comparisons, and 6148 // signed comparisons only happen in cases we don't care to warn about. 6149 // 6150 // We also don't care about value-dependent expressions or expressions 6151 // whose result is a constant. 6152 if (!T->hasUnsignedIntegerRepresentation() || IsComparisonConstant) 6153 return AnalyzeImpConvsInComparison(S, E); 6154 6155 // Check to see if one of the (unmodified) operands is of different 6156 // signedness. 6157 Expr *signedOperand, *unsignedOperand; 6158 if (LHS->getType()->hasSignedIntegerRepresentation()) { 6159 assert(!RHS->getType()->hasSignedIntegerRepresentation() && 6160 "unsigned comparison between two signed integer expressions?"); 6161 signedOperand = LHS; 6162 unsignedOperand = RHS; 6163 } else if (RHS->getType()->hasSignedIntegerRepresentation()) { 6164 signedOperand = RHS; 6165 unsignedOperand = LHS; 6166 } else { 6167 CheckTrivialUnsignedComparison(S, E); 6168 return AnalyzeImpConvsInComparison(S, E); 6169 } 6170 6171 // Otherwise, calculate the effective range of the signed operand. 6172 IntRange signedRange = GetExprRange(S.Context, signedOperand); 6173 6174 // Go ahead and analyze implicit conversions in the operands. Note 6175 // that we skip the implicit conversions on both sides. 6176 AnalyzeImplicitConversions(S, LHS, E->getOperatorLoc()); 6177 AnalyzeImplicitConversions(S, RHS, E->getOperatorLoc()); 6178 6179 // If the signed range is non-negative, -Wsign-compare won't fire, 6180 // but we should still check for comparisons which are always true 6181 // or false. 6182 if (signedRange.NonNegative) 6183 return CheckTrivialUnsignedComparison(S, E); 6184 6185 // For (in)equality comparisons, if the unsigned operand is a 6186 // constant which cannot collide with a overflowed signed operand, 6187 // then reinterpreting the signed operand as unsigned will not 6188 // change the result of the comparison. 6189 if (E->isEqualityOp()) { 6190 unsigned comparisonWidth = S.Context.getIntWidth(T); 6191 IntRange unsignedRange = GetExprRange(S.Context, unsignedOperand); 6192 6193 // We should never be unable to prove that the unsigned operand is 6194 // non-negative. 6195 assert(unsignedRange.NonNegative && "unsigned range includes negative?"); 6196 6197 if (unsignedRange.Width < comparisonWidth) 6198 return; 6199 } 6200 6201 S.DiagRuntimeBehavior(E->getOperatorLoc(), E, 6202 S.PDiag(diag::warn_mixed_sign_comparison) 6203 << LHS->getType() << RHS->getType() 6204 << LHS->getSourceRange() << RHS->getSourceRange()); 6205 } 6206 6207 /// Analyzes an attempt to assign the given value to a bitfield. 6208 /// 6209 /// Returns true if there was something fishy about the attempt. 6210 static bool AnalyzeBitFieldAssignment(Sema &S, FieldDecl *Bitfield, Expr *Init, 6211 SourceLocation InitLoc) { 6212 assert(Bitfield->isBitField()); 6213 if (Bitfield->isInvalidDecl()) 6214 return false; 6215 6216 // White-list bool bitfields. 6217 if (Bitfield->getType()->isBooleanType()) 6218 return false; 6219 6220 // Ignore value- or type-dependent expressions. 6221 if (Bitfield->getBitWidth()->isValueDependent() || 6222 Bitfield->getBitWidth()->isTypeDependent() || 6223 Init->isValueDependent() || 6224 Init->isTypeDependent()) 6225 return false; 6226 6227 Expr *OriginalInit = Init->IgnoreParenImpCasts(); 6228 6229 llvm::APSInt Value; 6230 if (!OriginalInit->EvaluateAsInt(Value, S.Context, Expr::SE_AllowSideEffects)) 6231 return false; 6232 6233 unsigned OriginalWidth = Value.getBitWidth(); 6234 unsigned FieldWidth = Bitfield->getBitWidthValue(S.Context); 6235 6236 if (OriginalWidth <= FieldWidth) 6237 return false; 6238 6239 // Compute the value which the bitfield will contain. 6240 llvm::APSInt TruncatedValue = Value.trunc(FieldWidth); 6241 TruncatedValue.setIsSigned(Bitfield->getType()->isSignedIntegerType()); 6242 6243 // Check whether the stored value is equal to the original value. 6244 TruncatedValue = TruncatedValue.extend(OriginalWidth); 6245 if (llvm::APSInt::isSameValue(Value, TruncatedValue)) 6246 return false; 6247 6248 // Special-case bitfields of width 1: booleans are naturally 0/1, and 6249 // therefore don't strictly fit into a signed bitfield of width 1. 6250 if (FieldWidth == 1 && Value == 1) 6251 return false; 6252 6253 std::string PrettyValue = Value.toString(10); 6254 std::string PrettyTrunc = TruncatedValue.toString(10); 6255 6256 S.Diag(InitLoc, diag::warn_impcast_bitfield_precision_constant) 6257 << PrettyValue << PrettyTrunc << OriginalInit->getType() 6258 << Init->getSourceRange(); 6259 6260 return true; 6261 } 6262 6263 /// Analyze the given simple or compound assignment for warning-worthy 6264 /// operations. 6265 static void AnalyzeAssignment(Sema &S, BinaryOperator *E) { 6266 // Just recurse on the LHS. 6267 AnalyzeImplicitConversions(S, E->getLHS(), E->getOperatorLoc()); 6268 6269 // We want to recurse on the RHS as normal unless we're assigning to 6270 // a bitfield. 6271 if (FieldDecl *Bitfield = E->getLHS()->getSourceBitField()) { 6272 if (AnalyzeBitFieldAssignment(S, Bitfield, E->getRHS(), 6273 E->getOperatorLoc())) { 6274 // Recurse, ignoring any implicit conversions on the RHS. 6275 return AnalyzeImplicitConversions(S, E->getRHS()->IgnoreParenImpCasts(), 6276 E->getOperatorLoc()); 6277 } 6278 } 6279 6280 AnalyzeImplicitConversions(S, E->getRHS(), E->getOperatorLoc()); 6281 } 6282 6283 /// Diagnose an implicit cast; purely a helper for CheckImplicitConversion. 6284 static void DiagnoseImpCast(Sema &S, Expr *E, QualType SourceType, QualType T, 6285 SourceLocation CContext, unsigned diag, 6286 bool pruneControlFlow = false) { 6287 if (pruneControlFlow) { 6288 S.DiagRuntimeBehavior(E->getExprLoc(), E, 6289 S.PDiag(diag) 6290 << SourceType << T << E->getSourceRange() 6291 << SourceRange(CContext)); 6292 return; 6293 } 6294 S.Diag(E->getExprLoc(), diag) 6295 << SourceType << T << E->getSourceRange() << SourceRange(CContext); 6296 } 6297 6298 /// Diagnose an implicit cast; purely a helper for CheckImplicitConversion. 6299 static void DiagnoseImpCast(Sema &S, Expr *E, QualType T, 6300 SourceLocation CContext, unsigned diag, 6301 bool pruneControlFlow = false) { 6302 DiagnoseImpCast(S, E, E->getType(), T, CContext, diag, pruneControlFlow); 6303 } 6304 6305 /// Diagnose an implicit cast from a literal expression. Does not warn when the 6306 /// cast wouldn't lose information. 6307 void DiagnoseFloatingLiteralImpCast(Sema &S, FloatingLiteral *FL, QualType T, 6308 SourceLocation CContext) { 6309 // Try to convert the literal exactly to an integer. If we can, don't warn. 6310 bool isExact = false; 6311 const llvm::APFloat &Value = FL->getValue(); 6312 llvm::APSInt IntegerValue(S.Context.getIntWidth(T), 6313 T->hasUnsignedIntegerRepresentation()); 6314 if (Value.convertToInteger(IntegerValue, 6315 llvm::APFloat::rmTowardZero, &isExact) 6316 == llvm::APFloat::opOK && isExact) 6317 return; 6318 6319 // FIXME: Force the precision of the source value down so we don't print 6320 // digits which are usually useless (we don't really care here if we 6321 // truncate a digit by accident in edge cases). Ideally, APFloat::toString 6322 // would automatically print the shortest representation, but it's a bit 6323 // tricky to implement. 6324 SmallString<16> PrettySourceValue; 6325 unsigned precision = llvm::APFloat::semanticsPrecision(Value.getSemantics()); 6326 precision = (precision * 59 + 195) / 196; 6327 Value.toString(PrettySourceValue, precision); 6328 6329 SmallString<16> PrettyTargetValue; 6330 if (T->isSpecificBuiltinType(BuiltinType::Bool)) 6331 PrettyTargetValue = IntegerValue == 0 ? "false" : "true"; 6332 else 6333 IntegerValue.toString(PrettyTargetValue); 6334 6335 S.Diag(FL->getExprLoc(), diag::warn_impcast_literal_float_to_integer) 6336 << FL->getType() << T.getUnqualifiedType() << PrettySourceValue 6337 << PrettyTargetValue << FL->getSourceRange() << SourceRange(CContext); 6338 } 6339 6340 std::string PrettyPrintInRange(const llvm::APSInt &Value, IntRange Range) { 6341 if (!Range.Width) return "0"; 6342 6343 llvm::APSInt ValueInRange = Value; 6344 ValueInRange.setIsSigned(!Range.NonNegative); 6345 ValueInRange = ValueInRange.trunc(Range.Width); 6346 return ValueInRange.toString(10); 6347 } 6348 6349 static bool IsImplicitBoolFloatConversion(Sema &S, Expr *Ex, bool ToBool) { 6350 if (!isa<ImplicitCastExpr>(Ex)) 6351 return false; 6352 6353 Expr *InnerE = Ex->IgnoreParenImpCasts(); 6354 const Type *Target = S.Context.getCanonicalType(Ex->getType()).getTypePtr(); 6355 const Type *Source = 6356 S.Context.getCanonicalType(InnerE->getType()).getTypePtr(); 6357 if (Target->isDependentType()) 6358 return false; 6359 6360 const BuiltinType *FloatCandidateBT = 6361 dyn_cast<BuiltinType>(ToBool ? Source : Target); 6362 const Type *BoolCandidateType = ToBool ? Target : Source; 6363 6364 return (BoolCandidateType->isSpecificBuiltinType(BuiltinType::Bool) && 6365 FloatCandidateBT && (FloatCandidateBT->isFloatingPoint())); 6366 } 6367 6368 void CheckImplicitArgumentConversions(Sema &S, CallExpr *TheCall, 6369 SourceLocation CC) { 6370 unsigned NumArgs = TheCall->getNumArgs(); 6371 for (unsigned i = 0; i < NumArgs; ++i) { 6372 Expr *CurrA = TheCall->getArg(i); 6373 if (!IsImplicitBoolFloatConversion(S, CurrA, true)) 6374 continue; 6375 6376 bool IsSwapped = ((i > 0) && 6377 IsImplicitBoolFloatConversion(S, TheCall->getArg(i - 1), false)); 6378 IsSwapped |= ((i < (NumArgs - 1)) && 6379 IsImplicitBoolFloatConversion(S, TheCall->getArg(i + 1), false)); 6380 if (IsSwapped) { 6381 // Warn on this floating-point to bool conversion. 6382 DiagnoseImpCast(S, CurrA->IgnoreParenImpCasts(), 6383 CurrA->getType(), CC, 6384 diag::warn_impcast_floating_point_to_bool); 6385 } 6386 } 6387 } 6388 6389 static void DiagnoseNullConversion(Sema &S, Expr *E, QualType T, 6390 SourceLocation CC) { 6391 if (S.Diags.isIgnored(diag::warn_impcast_null_pointer_to_integer, 6392 E->getExprLoc())) 6393 return; 6394 6395 // Check for NULL (GNUNull) or nullptr (CXX11_nullptr). 6396 const Expr::NullPointerConstantKind NullKind = 6397 E->isNullPointerConstant(S.Context, Expr::NPC_ValueDependentIsNotNull); 6398 if (NullKind != Expr::NPCK_GNUNull && NullKind != Expr::NPCK_CXX11_nullptr) 6399 return; 6400 6401 // Return if target type is a safe conversion. 6402 if (T->isAnyPointerType() || T->isBlockPointerType() || 6403 T->isMemberPointerType() || !T->isScalarType() || T->isNullPtrType()) 6404 return; 6405 6406 SourceLocation Loc = E->getSourceRange().getBegin(); 6407 6408 // __null is usually wrapped in a macro. Go up a macro if that is the case. 6409 if (NullKind == Expr::NPCK_GNUNull) { 6410 if (Loc.isMacroID()) 6411 Loc = S.SourceMgr.getImmediateExpansionRange(Loc).first; 6412 } 6413 6414 // Only warn if the null and context location are in the same macro expansion. 6415 if (S.SourceMgr.getFileID(Loc) != S.SourceMgr.getFileID(CC)) 6416 return; 6417 6418 S.Diag(Loc, diag::warn_impcast_null_pointer_to_integer) 6419 << (NullKind == Expr::NPCK_CXX11_nullptr) << T << clang::SourceRange(CC) 6420 << FixItHint::CreateReplacement(Loc, 6421 S.getFixItZeroLiteralForType(T, Loc)); 6422 } 6423 6424 void CheckImplicitConversion(Sema &S, Expr *E, QualType T, 6425 SourceLocation CC, bool *ICContext = nullptr) { 6426 if (E->isTypeDependent() || E->isValueDependent()) return; 6427 6428 const Type *Source = S.Context.getCanonicalType(E->getType()).getTypePtr(); 6429 const Type *Target = S.Context.getCanonicalType(T).getTypePtr(); 6430 if (Source == Target) return; 6431 if (Target->isDependentType()) return; 6432 6433 // If the conversion context location is invalid don't complain. We also 6434 // don't want to emit a warning if the issue occurs from the expansion of 6435 // a system macro. The problem is that 'getSpellingLoc()' is slow, so we 6436 // delay this check as long as possible. Once we detect we are in that 6437 // scenario, we just return. 6438 if (CC.isInvalid()) 6439 return; 6440 6441 // Diagnose implicit casts to bool. 6442 if (Target->isSpecificBuiltinType(BuiltinType::Bool)) { 6443 if (isa<StringLiteral>(E)) 6444 // Warn on string literal to bool. Checks for string literals in logical 6445 // and expressions, for instance, assert(0 && "error here"), are 6446 // prevented by a check in AnalyzeImplicitConversions(). 6447 return DiagnoseImpCast(S, E, T, CC, 6448 diag::warn_impcast_string_literal_to_bool); 6449 if (isa<ObjCStringLiteral>(E) || isa<ObjCArrayLiteral>(E) || 6450 isa<ObjCDictionaryLiteral>(E) || isa<ObjCBoxedExpr>(E)) { 6451 // This covers the literal expressions that evaluate to Objective-C 6452 // objects. 6453 return DiagnoseImpCast(S, E, T, CC, 6454 diag::warn_impcast_objective_c_literal_to_bool); 6455 } 6456 if (Source->isPointerType() || Source->canDecayToPointerType()) { 6457 // Warn on pointer to bool conversion that is always true. 6458 S.DiagnoseAlwaysNonNullPointer(E, Expr::NPCK_NotNull, /*IsEqual*/ false, 6459 SourceRange(CC)); 6460 } 6461 } 6462 6463 // Strip vector types. 6464 if (isa<VectorType>(Source)) { 6465 if (!isa<VectorType>(Target)) { 6466 if (S.SourceMgr.isInSystemMacro(CC)) 6467 return; 6468 return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_vector_scalar); 6469 } 6470 6471 // If the vector cast is cast between two vectors of the same size, it is 6472 // a bitcast, not a conversion. 6473 if (S.Context.getTypeSize(Source) == S.Context.getTypeSize(Target)) 6474 return; 6475 6476 Source = cast<VectorType>(Source)->getElementType().getTypePtr(); 6477 Target = cast<VectorType>(Target)->getElementType().getTypePtr(); 6478 } 6479 if (auto VecTy = dyn_cast<VectorType>(Target)) 6480 Target = VecTy->getElementType().getTypePtr(); 6481 6482 // Strip complex types. 6483 if (isa<ComplexType>(Source)) { 6484 if (!isa<ComplexType>(Target)) { 6485 if (S.SourceMgr.isInSystemMacro(CC)) 6486 return; 6487 6488 return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_complex_scalar); 6489 } 6490 6491 Source = cast<ComplexType>(Source)->getElementType().getTypePtr(); 6492 Target = cast<ComplexType>(Target)->getElementType().getTypePtr(); 6493 } 6494 6495 const BuiltinType *SourceBT = dyn_cast<BuiltinType>(Source); 6496 const BuiltinType *TargetBT = dyn_cast<BuiltinType>(Target); 6497 6498 // If the source is floating point... 6499 if (SourceBT && SourceBT->isFloatingPoint()) { 6500 // ...and the target is floating point... 6501 if (TargetBT && TargetBT->isFloatingPoint()) { 6502 // ...then warn if we're dropping FP rank. 6503 6504 // Builtin FP kinds are ordered by increasing FP rank. 6505 if (SourceBT->getKind() > TargetBT->getKind()) { 6506 // Don't warn about float constants that are precisely 6507 // representable in the target type. 6508 Expr::EvalResult result; 6509 if (E->EvaluateAsRValue(result, S.Context)) { 6510 // Value might be a float, a float vector, or a float complex. 6511 if (IsSameFloatAfterCast(result.Val, 6512 S.Context.getFloatTypeSemantics(QualType(TargetBT, 0)), 6513 S.Context.getFloatTypeSemantics(QualType(SourceBT, 0)))) 6514 return; 6515 } 6516 6517 if (S.SourceMgr.isInSystemMacro(CC)) 6518 return; 6519 6520 DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_float_precision); 6521 } 6522 return; 6523 } 6524 6525 // If the target is integral, always warn. 6526 if (TargetBT && TargetBT->isInteger()) { 6527 if (S.SourceMgr.isInSystemMacro(CC)) 6528 return; 6529 6530 Expr *InnerE = E->IgnoreParenImpCasts(); 6531 // We also want to warn on, e.g., "int i = -1.234" 6532 if (UnaryOperator *UOp = dyn_cast<UnaryOperator>(InnerE)) 6533 if (UOp->getOpcode() == UO_Minus || UOp->getOpcode() == UO_Plus) 6534 InnerE = UOp->getSubExpr()->IgnoreParenImpCasts(); 6535 6536 if (FloatingLiteral *FL = dyn_cast<FloatingLiteral>(InnerE)) { 6537 DiagnoseFloatingLiteralImpCast(S, FL, T, CC); 6538 } else { 6539 DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_float_integer); 6540 } 6541 } 6542 6543 // If the target is bool, warn if expr is a function or method call. 6544 if (Target->isSpecificBuiltinType(BuiltinType::Bool) && 6545 isa<CallExpr>(E)) { 6546 // Check last argument of function call to see if it is an 6547 // implicit cast from a type matching the type the result 6548 // is being cast to. 6549 CallExpr *CEx = cast<CallExpr>(E); 6550 unsigned NumArgs = CEx->getNumArgs(); 6551 if (NumArgs > 0) { 6552 Expr *LastA = CEx->getArg(NumArgs - 1); 6553 Expr *InnerE = LastA->IgnoreParenImpCasts(); 6554 const Type *InnerType = 6555 S.Context.getCanonicalType(InnerE->getType()).getTypePtr(); 6556 if (isa<ImplicitCastExpr>(LastA) && (InnerType == Target)) { 6557 // Warn on this floating-point to bool conversion 6558 DiagnoseImpCast(S, E, T, CC, 6559 diag::warn_impcast_floating_point_to_bool); 6560 } 6561 } 6562 } 6563 return; 6564 } 6565 6566 DiagnoseNullConversion(S, E, T, CC); 6567 6568 if (!Source->isIntegerType() || !Target->isIntegerType()) 6569 return; 6570 6571 // TODO: remove this early return once the false positives for constant->bool 6572 // in templates, macros, etc, are reduced or removed. 6573 if (Target->isSpecificBuiltinType(BuiltinType::Bool)) 6574 return; 6575 6576 IntRange SourceRange = GetExprRange(S.Context, E); 6577 IntRange TargetRange = IntRange::forTargetOfCanonicalType(S.Context, Target); 6578 6579 if (SourceRange.Width > TargetRange.Width) { 6580 // If the source is a constant, use a default-on diagnostic. 6581 // TODO: this should happen for bitfield stores, too. 6582 llvm::APSInt Value(32); 6583 if (E->isIntegerConstantExpr(Value, S.Context)) { 6584 if (S.SourceMgr.isInSystemMacro(CC)) 6585 return; 6586 6587 std::string PrettySourceValue = Value.toString(10); 6588 std::string PrettyTargetValue = PrettyPrintInRange(Value, TargetRange); 6589 6590 S.DiagRuntimeBehavior(E->getExprLoc(), E, 6591 S.PDiag(diag::warn_impcast_integer_precision_constant) 6592 << PrettySourceValue << PrettyTargetValue 6593 << E->getType() << T << E->getSourceRange() 6594 << clang::SourceRange(CC)); 6595 return; 6596 } 6597 6598 // People want to build with -Wshorten-64-to-32 and not -Wconversion. 6599 if (S.SourceMgr.isInSystemMacro(CC)) 6600 return; 6601 6602 if (TargetRange.Width == 32 && S.Context.getIntWidth(E->getType()) == 64) 6603 return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_integer_64_32, 6604 /* pruneControlFlow */ true); 6605 return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_integer_precision); 6606 } 6607 6608 if ((TargetRange.NonNegative && !SourceRange.NonNegative) || 6609 (!TargetRange.NonNegative && SourceRange.NonNegative && 6610 SourceRange.Width == TargetRange.Width)) { 6611 6612 if (S.SourceMgr.isInSystemMacro(CC)) 6613 return; 6614 6615 unsigned DiagID = diag::warn_impcast_integer_sign; 6616 6617 // Traditionally, gcc has warned about this under -Wsign-compare. 6618 // We also want to warn about it in -Wconversion. 6619 // So if -Wconversion is off, use a completely identical diagnostic 6620 // in the sign-compare group. 6621 // The conditional-checking code will 6622 if (ICContext) { 6623 DiagID = diag::warn_impcast_integer_sign_conditional; 6624 *ICContext = true; 6625 } 6626 6627 return DiagnoseImpCast(S, E, T, CC, DiagID); 6628 } 6629 6630 // Diagnose conversions between different enumeration types. 6631 // In C, we pretend that the type of an EnumConstantDecl is its enumeration 6632 // type, to give us better diagnostics. 6633 QualType SourceType = E->getType(); 6634 if (!S.getLangOpts().CPlusPlus) { 6635 if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) 6636 if (EnumConstantDecl *ECD = dyn_cast<EnumConstantDecl>(DRE->getDecl())) { 6637 EnumDecl *Enum = cast<EnumDecl>(ECD->getDeclContext()); 6638 SourceType = S.Context.getTypeDeclType(Enum); 6639 Source = S.Context.getCanonicalType(SourceType).getTypePtr(); 6640 } 6641 } 6642 6643 if (const EnumType *SourceEnum = Source->getAs<EnumType>()) 6644 if (const EnumType *TargetEnum = Target->getAs<EnumType>()) 6645 if (SourceEnum->getDecl()->hasNameForLinkage() && 6646 TargetEnum->getDecl()->hasNameForLinkage() && 6647 SourceEnum != TargetEnum) { 6648 if (S.SourceMgr.isInSystemMacro(CC)) 6649 return; 6650 6651 return DiagnoseImpCast(S, E, SourceType, T, CC, 6652 diag::warn_impcast_different_enum_types); 6653 } 6654 6655 return; 6656 } 6657 6658 void CheckConditionalOperator(Sema &S, ConditionalOperator *E, 6659 SourceLocation CC, QualType T); 6660 6661 void CheckConditionalOperand(Sema &S, Expr *E, QualType T, 6662 SourceLocation CC, bool &ICContext) { 6663 E = E->IgnoreParenImpCasts(); 6664 6665 if (isa<ConditionalOperator>(E)) 6666 return CheckConditionalOperator(S, cast<ConditionalOperator>(E), CC, T); 6667 6668 AnalyzeImplicitConversions(S, E, CC); 6669 if (E->getType() != T) 6670 return CheckImplicitConversion(S, E, T, CC, &ICContext); 6671 return; 6672 } 6673 6674 void CheckConditionalOperator(Sema &S, ConditionalOperator *E, 6675 SourceLocation CC, QualType T) { 6676 AnalyzeImplicitConversions(S, E->getCond(), E->getQuestionLoc()); 6677 6678 bool Suspicious = false; 6679 CheckConditionalOperand(S, E->getTrueExpr(), T, CC, Suspicious); 6680 CheckConditionalOperand(S, E->getFalseExpr(), T, CC, Suspicious); 6681 6682 // If -Wconversion would have warned about either of the candidates 6683 // for a signedness conversion to the context type... 6684 if (!Suspicious) return; 6685 6686 // ...but it's currently ignored... 6687 if (!S.Diags.isIgnored(diag::warn_impcast_integer_sign_conditional, CC)) 6688 return; 6689 6690 // ...then check whether it would have warned about either of the 6691 // candidates for a signedness conversion to the condition type. 6692 if (E->getType() == T) return; 6693 6694 Suspicious = false; 6695 CheckImplicitConversion(S, E->getTrueExpr()->IgnoreParenImpCasts(), 6696 E->getType(), CC, &Suspicious); 6697 if (!Suspicious) 6698 CheckImplicitConversion(S, E->getFalseExpr()->IgnoreParenImpCasts(), 6699 E->getType(), CC, &Suspicious); 6700 } 6701 6702 /// CheckBoolLikeConversion - Check conversion of given expression to boolean. 6703 /// Input argument E is a logical expression. 6704 static void CheckBoolLikeConversion(Sema &S, Expr *E, SourceLocation CC) { 6705 if (S.getLangOpts().Bool) 6706 return; 6707 CheckImplicitConversion(S, E->IgnoreParenImpCasts(), S.Context.BoolTy, CC); 6708 } 6709 6710 /// AnalyzeImplicitConversions - Find and report any interesting 6711 /// implicit conversions in the given expression. There are a couple 6712 /// of competing diagnostics here, -Wconversion and -Wsign-compare. 6713 void AnalyzeImplicitConversions(Sema &S, Expr *OrigE, SourceLocation CC) { 6714 QualType T = OrigE->getType(); 6715 Expr *E = OrigE->IgnoreParenImpCasts(); 6716 6717 if (E->isTypeDependent() || E->isValueDependent()) 6718 return; 6719 6720 // For conditional operators, we analyze the arguments as if they 6721 // were being fed directly into the output. 6722 if (isa<ConditionalOperator>(E)) { 6723 ConditionalOperator *CO = cast<ConditionalOperator>(E); 6724 CheckConditionalOperator(S, CO, CC, T); 6725 return; 6726 } 6727 6728 // Check implicit argument conversions for function calls. 6729 if (CallExpr *Call = dyn_cast<CallExpr>(E)) 6730 CheckImplicitArgumentConversions(S, Call, CC); 6731 6732 // Go ahead and check any implicit conversions we might have skipped. 6733 // The non-canonical typecheck is just an optimization; 6734 // CheckImplicitConversion will filter out dead implicit conversions. 6735 if (E->getType() != T) 6736 CheckImplicitConversion(S, E, T, CC); 6737 6738 // Now continue drilling into this expression. 6739 6740 if (PseudoObjectExpr * POE = dyn_cast<PseudoObjectExpr>(E)) { 6741 if (POE->getResultExpr()) 6742 E = POE->getResultExpr(); 6743 } 6744 6745 if (const OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(E)) 6746 return AnalyzeImplicitConversions(S, OVE->getSourceExpr(), CC); 6747 6748 // Skip past explicit casts. 6749 if (isa<ExplicitCastExpr>(E)) { 6750 E = cast<ExplicitCastExpr>(E)->getSubExpr()->IgnoreParenImpCasts(); 6751 return AnalyzeImplicitConversions(S, E, CC); 6752 } 6753 6754 if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) { 6755 // Do a somewhat different check with comparison operators. 6756 if (BO->isComparisonOp()) 6757 return AnalyzeComparison(S, BO); 6758 6759 // And with simple assignments. 6760 if (BO->getOpcode() == BO_Assign) 6761 return AnalyzeAssignment(S, BO); 6762 } 6763 6764 // These break the otherwise-useful invariant below. Fortunately, 6765 // we don't really need to recurse into them, because any internal 6766 // expressions should have been analyzed already when they were 6767 // built into statements. 6768 if (isa<StmtExpr>(E)) return; 6769 6770 // Don't descend into unevaluated contexts. 6771 if (isa<UnaryExprOrTypeTraitExpr>(E)) return; 6772 6773 // Now just recurse over the expression's children. 6774 CC = E->getExprLoc(); 6775 BinaryOperator *BO = dyn_cast<BinaryOperator>(E); 6776 bool IsLogicalAndOperator = BO && BO->getOpcode() == BO_LAnd; 6777 for (Stmt::child_range I = E->children(); I; ++I) { 6778 Expr *ChildExpr = dyn_cast_or_null<Expr>(*I); 6779 if (!ChildExpr) 6780 continue; 6781 6782 if (IsLogicalAndOperator && 6783 isa<StringLiteral>(ChildExpr->IgnoreParenImpCasts())) 6784 // Ignore checking string literals that are in logical and operators. 6785 // This is a common pattern for asserts. 6786 continue; 6787 AnalyzeImplicitConversions(S, ChildExpr, CC); 6788 } 6789 6790 if (BO && BO->isLogicalOp()) { 6791 Expr *SubExpr = BO->getLHS()->IgnoreParenImpCasts(); 6792 if (!IsLogicalAndOperator || !isa<StringLiteral>(SubExpr)) 6793 ::CheckBoolLikeConversion(S, SubExpr, BO->getExprLoc()); 6794 6795 SubExpr = BO->getRHS()->IgnoreParenImpCasts(); 6796 if (!IsLogicalAndOperator || !isa<StringLiteral>(SubExpr)) 6797 ::CheckBoolLikeConversion(S, SubExpr, BO->getExprLoc()); 6798 } 6799 6800 if (const UnaryOperator *U = dyn_cast<UnaryOperator>(E)) 6801 if (U->getOpcode() == UO_LNot) 6802 ::CheckBoolLikeConversion(S, U->getSubExpr(), CC); 6803 } 6804 6805 } // end anonymous namespace 6806 6807 enum { 6808 AddressOf, 6809 FunctionPointer, 6810 ArrayPointer 6811 }; 6812 6813 // Helper function for Sema::DiagnoseAlwaysNonNullPointer. 6814 // Returns true when emitting a warning about taking the address of a reference. 6815 static bool CheckForReference(Sema &SemaRef, const Expr *E, 6816 PartialDiagnostic PD) { 6817 E = E->IgnoreParenImpCasts(); 6818 6819 const FunctionDecl *FD = nullptr; 6820 6821 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) { 6822 if (!DRE->getDecl()->getType()->isReferenceType()) 6823 return false; 6824 } else if (const MemberExpr *M = dyn_cast<MemberExpr>(E)) { 6825 if (!M->getMemberDecl()->getType()->isReferenceType()) 6826 return false; 6827 } else if (const CallExpr *Call = dyn_cast<CallExpr>(E)) { 6828 if (!Call->getCallReturnType()->isReferenceType()) 6829 return false; 6830 FD = Call->getDirectCallee(); 6831 } else { 6832 return false; 6833 } 6834 6835 SemaRef.Diag(E->getExprLoc(), PD); 6836 6837 // If possible, point to location of function. 6838 if (FD) { 6839 SemaRef.Diag(FD->getLocation(), diag::note_reference_is_return_value) << FD; 6840 } 6841 6842 return true; 6843 } 6844 6845 // Returns true if the SourceLocation is expanded from any macro body. 6846 // Returns false if the SourceLocation is invalid, is from not in a macro 6847 // expansion, or is from expanded from a top-level macro argument. 6848 static bool IsInAnyMacroBody(const SourceManager &SM, SourceLocation Loc) { 6849 if (Loc.isInvalid()) 6850 return false; 6851 6852 while (Loc.isMacroID()) { 6853 if (SM.isMacroBodyExpansion(Loc)) 6854 return true; 6855 Loc = SM.getImmediateMacroCallerLoc(Loc); 6856 } 6857 6858 return false; 6859 } 6860 6861 /// \brief Diagnose pointers that are always non-null. 6862 /// \param E the expression containing the pointer 6863 /// \param NullKind NPCK_NotNull if E is a cast to bool, otherwise, E is 6864 /// compared to a null pointer 6865 /// \param IsEqual True when the comparison is equal to a null pointer 6866 /// \param Range Extra SourceRange to highlight in the diagnostic 6867 void Sema::DiagnoseAlwaysNonNullPointer(Expr *E, 6868 Expr::NullPointerConstantKind NullKind, 6869 bool IsEqual, SourceRange Range) { 6870 if (!E) 6871 return; 6872 6873 // Don't warn inside macros. 6874 if (E->getExprLoc().isMacroID()) { 6875 const SourceManager &SM = getSourceManager(); 6876 if (IsInAnyMacroBody(SM, E->getExprLoc()) || 6877 IsInAnyMacroBody(SM, Range.getBegin())) 6878 return; 6879 } 6880 E = E->IgnoreImpCasts(); 6881 6882 const bool IsCompare = NullKind != Expr::NPCK_NotNull; 6883 6884 if (isa<CXXThisExpr>(E)) { 6885 unsigned DiagID = IsCompare ? diag::warn_this_null_compare 6886 : diag::warn_this_bool_conversion; 6887 Diag(E->getExprLoc(), DiagID) << E->getSourceRange() << Range << IsEqual; 6888 return; 6889 } 6890 6891 bool IsAddressOf = false; 6892 6893 if (UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) { 6894 if (UO->getOpcode() != UO_AddrOf) 6895 return; 6896 IsAddressOf = true; 6897 E = UO->getSubExpr(); 6898 } 6899 6900 if (IsAddressOf) { 6901 unsigned DiagID = IsCompare 6902 ? diag::warn_address_of_reference_null_compare 6903 : diag::warn_address_of_reference_bool_conversion; 6904 PartialDiagnostic PD = PDiag(DiagID) << E->getSourceRange() << Range 6905 << IsEqual; 6906 if (CheckForReference(*this, E, PD)) { 6907 return; 6908 } 6909 } 6910 6911 // Expect to find a single Decl. Skip anything more complicated. 6912 ValueDecl *D = nullptr; 6913 if (DeclRefExpr *R = dyn_cast<DeclRefExpr>(E)) { 6914 D = R->getDecl(); 6915 } else if (MemberExpr *M = dyn_cast<MemberExpr>(E)) { 6916 D = M->getMemberDecl(); 6917 } 6918 6919 // Weak Decls can be null. 6920 if (!D || D->isWeak()) 6921 return; 6922 6923 // Check for parameter decl with nonnull attribute 6924 if (const ParmVarDecl* PV = dyn_cast<ParmVarDecl>(D)) { 6925 if (getCurFunction() && !getCurFunction()->ModifiedNonNullParams.count(PV)) 6926 if (const FunctionDecl* FD = dyn_cast<FunctionDecl>(PV->getDeclContext())) { 6927 unsigned NumArgs = FD->getNumParams(); 6928 llvm::SmallBitVector AttrNonNull(NumArgs); 6929 for (const auto *NonNull : FD->specific_attrs<NonNullAttr>()) { 6930 if (!NonNull->args_size()) { 6931 AttrNonNull.set(0, NumArgs); 6932 break; 6933 } 6934 for (unsigned Val : NonNull->args()) { 6935 if (Val >= NumArgs) 6936 continue; 6937 AttrNonNull.set(Val); 6938 } 6939 } 6940 if (!AttrNonNull.empty()) 6941 for (unsigned i = 0; i < NumArgs; ++i) 6942 if (FD->getParamDecl(i) == PV && 6943 (AttrNonNull[i] || PV->hasAttr<NonNullAttr>())) { 6944 std::string Str; 6945 llvm::raw_string_ostream S(Str); 6946 E->printPretty(S, nullptr, getPrintingPolicy()); 6947 unsigned DiagID = IsCompare ? diag::warn_nonnull_parameter_compare 6948 : diag::warn_cast_nonnull_to_bool; 6949 Diag(E->getExprLoc(), DiagID) << S.str() << E->getSourceRange() 6950 << Range << IsEqual; 6951 return; 6952 } 6953 } 6954 } 6955 6956 QualType T = D->getType(); 6957 const bool IsArray = T->isArrayType(); 6958 const bool IsFunction = T->isFunctionType(); 6959 6960 // Address of function is used to silence the function warning. 6961 if (IsAddressOf && IsFunction) { 6962 return; 6963 } 6964 6965 // Found nothing. 6966 if (!IsAddressOf && !IsFunction && !IsArray) 6967 return; 6968 6969 // Pretty print the expression for the diagnostic. 6970 std::string Str; 6971 llvm::raw_string_ostream S(Str); 6972 E->printPretty(S, nullptr, getPrintingPolicy()); 6973 6974 unsigned DiagID = IsCompare ? diag::warn_null_pointer_compare 6975 : diag::warn_impcast_pointer_to_bool; 6976 unsigned DiagType; 6977 if (IsAddressOf) 6978 DiagType = AddressOf; 6979 else if (IsFunction) 6980 DiagType = FunctionPointer; 6981 else if (IsArray) 6982 DiagType = ArrayPointer; 6983 else 6984 llvm_unreachable("Could not determine diagnostic."); 6985 Diag(E->getExprLoc(), DiagID) << DiagType << S.str() << E->getSourceRange() 6986 << Range << IsEqual; 6987 6988 if (!IsFunction) 6989 return; 6990 6991 // Suggest '&' to silence the function warning. 6992 Diag(E->getExprLoc(), diag::note_function_warning_silence) 6993 << FixItHint::CreateInsertion(E->getLocStart(), "&"); 6994 6995 // Check to see if '()' fixit should be emitted. 6996 QualType ReturnType; 6997 UnresolvedSet<4> NonTemplateOverloads; 6998 tryExprAsCall(*E, ReturnType, NonTemplateOverloads); 6999 if (ReturnType.isNull()) 7000 return; 7001 7002 if (IsCompare) { 7003 // There are two cases here. If there is null constant, the only suggest 7004 // for a pointer return type. If the null is 0, then suggest if the return 7005 // type is a pointer or an integer type. 7006 if (!ReturnType->isPointerType()) { 7007 if (NullKind == Expr::NPCK_ZeroExpression || 7008 NullKind == Expr::NPCK_ZeroLiteral) { 7009 if (!ReturnType->isIntegerType()) 7010 return; 7011 } else { 7012 return; 7013 } 7014 } 7015 } else { // !IsCompare 7016 // For function to bool, only suggest if the function pointer has bool 7017 // return type. 7018 if (!ReturnType->isSpecificBuiltinType(BuiltinType::Bool)) 7019 return; 7020 } 7021 Diag(E->getExprLoc(), diag::note_function_to_function_call) 7022 << FixItHint::CreateInsertion(getLocForEndOfToken(E->getLocEnd()), "()"); 7023 } 7024 7025 7026 /// Diagnoses "dangerous" implicit conversions within the given 7027 /// expression (which is a full expression). Implements -Wconversion 7028 /// and -Wsign-compare. 7029 /// 7030 /// \param CC the "context" location of the implicit conversion, i.e. 7031 /// the most location of the syntactic entity requiring the implicit 7032 /// conversion 7033 void Sema::CheckImplicitConversions(Expr *E, SourceLocation CC) { 7034 // Don't diagnose in unevaluated contexts. 7035 if (isUnevaluatedContext()) 7036 return; 7037 7038 // Don't diagnose for value- or type-dependent expressions. 7039 if (E->isTypeDependent() || E->isValueDependent()) 7040 return; 7041 7042 // Check for array bounds violations in cases where the check isn't triggered 7043 // elsewhere for other Expr types (like BinaryOperators), e.g. when an 7044 // ArraySubscriptExpr is on the RHS of a variable initialization. 7045 CheckArrayAccess(E); 7046 7047 // This is not the right CC for (e.g.) a variable initialization. 7048 AnalyzeImplicitConversions(*this, E, CC); 7049 } 7050 7051 /// CheckBoolLikeConversion - Check conversion of given expression to boolean. 7052 /// Input argument E is a logical expression. 7053 void Sema::CheckBoolLikeConversion(Expr *E, SourceLocation CC) { 7054 ::CheckBoolLikeConversion(*this, E, CC); 7055 } 7056 7057 /// Diagnose when expression is an integer constant expression and its evaluation 7058 /// results in integer overflow 7059 void Sema::CheckForIntOverflow (Expr *E) { 7060 if (isa<BinaryOperator>(E->IgnoreParenCasts())) 7061 E->IgnoreParenCasts()->EvaluateForOverflow(Context); 7062 } 7063 7064 namespace { 7065 /// \brief Visitor for expressions which looks for unsequenced operations on the 7066 /// same object. 7067 class SequenceChecker : public EvaluatedExprVisitor<SequenceChecker> { 7068 typedef EvaluatedExprVisitor<SequenceChecker> Base; 7069 7070 /// \brief A tree of sequenced regions within an expression. Two regions are 7071 /// unsequenced if one is an ancestor or a descendent of the other. When we 7072 /// finish processing an expression with sequencing, such as a comma 7073 /// expression, we fold its tree nodes into its parent, since they are 7074 /// unsequenced with respect to nodes we will visit later. 7075 class SequenceTree { 7076 struct Value { 7077 explicit Value(unsigned Parent) : Parent(Parent), Merged(false) {} 7078 unsigned Parent : 31; 7079 bool Merged : 1; 7080 }; 7081 SmallVector<Value, 8> Values; 7082 7083 public: 7084 /// \brief A region within an expression which may be sequenced with respect 7085 /// to some other region. 7086 class Seq { 7087 explicit Seq(unsigned N) : Index(N) {} 7088 unsigned Index; 7089 friend class SequenceTree; 7090 public: 7091 Seq() : Index(0) {} 7092 }; 7093 7094 SequenceTree() { Values.push_back(Value(0)); } 7095 Seq root() const { return Seq(0); } 7096 7097 /// \brief Create a new sequence of operations, which is an unsequenced 7098 /// subset of \p Parent. This sequence of operations is sequenced with 7099 /// respect to other children of \p Parent. 7100 Seq allocate(Seq Parent) { 7101 Values.push_back(Value(Parent.Index)); 7102 return Seq(Values.size() - 1); 7103 } 7104 7105 /// \brief Merge a sequence of operations into its parent. 7106 void merge(Seq S) { 7107 Values[S.Index].Merged = true; 7108 } 7109 7110 /// \brief Determine whether two operations are unsequenced. This operation 7111 /// is asymmetric: \p Cur should be the more recent sequence, and \p Old 7112 /// should have been merged into its parent as appropriate. 7113 bool isUnsequenced(Seq Cur, Seq Old) { 7114 unsigned C = representative(Cur.Index); 7115 unsigned Target = representative(Old.Index); 7116 while (C >= Target) { 7117 if (C == Target) 7118 return true; 7119 C = Values[C].Parent; 7120 } 7121 return false; 7122 } 7123 7124 private: 7125 /// \brief Pick a representative for a sequence. 7126 unsigned representative(unsigned K) { 7127 if (Values[K].Merged) 7128 // Perform path compression as we go. 7129 return Values[K].Parent = representative(Values[K].Parent); 7130 return K; 7131 } 7132 }; 7133 7134 /// An object for which we can track unsequenced uses. 7135 typedef NamedDecl *Object; 7136 7137 /// Different flavors of object usage which we track. We only track the 7138 /// least-sequenced usage of each kind. 7139 enum UsageKind { 7140 /// A read of an object. Multiple unsequenced reads are OK. 7141 UK_Use, 7142 /// A modification of an object which is sequenced before the value 7143 /// computation of the expression, such as ++n in C++. 7144 UK_ModAsValue, 7145 /// A modification of an object which is not sequenced before the value 7146 /// computation of the expression, such as n++. 7147 UK_ModAsSideEffect, 7148 7149 UK_Count = UK_ModAsSideEffect + 1 7150 }; 7151 7152 struct Usage { 7153 Usage() : Use(nullptr), Seq() {} 7154 Expr *Use; 7155 SequenceTree::Seq Seq; 7156 }; 7157 7158 struct UsageInfo { 7159 UsageInfo() : Diagnosed(false) {} 7160 Usage Uses[UK_Count]; 7161 /// Have we issued a diagnostic for this variable already? 7162 bool Diagnosed; 7163 }; 7164 typedef llvm::SmallDenseMap<Object, UsageInfo, 16> UsageInfoMap; 7165 7166 Sema &SemaRef; 7167 /// Sequenced regions within the expression. 7168 SequenceTree Tree; 7169 /// Declaration modifications and references which we have seen. 7170 UsageInfoMap UsageMap; 7171 /// The region we are currently within. 7172 SequenceTree::Seq Region; 7173 /// Filled in with declarations which were modified as a side-effect 7174 /// (that is, post-increment operations). 7175 SmallVectorImpl<std::pair<Object, Usage> > *ModAsSideEffect; 7176 /// Expressions to check later. We defer checking these to reduce 7177 /// stack usage. 7178 SmallVectorImpl<Expr *> &WorkList; 7179 7180 /// RAII object wrapping the visitation of a sequenced subexpression of an 7181 /// expression. At the end of this process, the side-effects of the evaluation 7182 /// become sequenced with respect to the value computation of the result, so 7183 /// we downgrade any UK_ModAsSideEffect within the evaluation to 7184 /// UK_ModAsValue. 7185 struct SequencedSubexpression { 7186 SequencedSubexpression(SequenceChecker &Self) 7187 : Self(Self), OldModAsSideEffect(Self.ModAsSideEffect) { 7188 Self.ModAsSideEffect = &ModAsSideEffect; 7189 } 7190 ~SequencedSubexpression() { 7191 for (auto MI = ModAsSideEffect.rbegin(), ME = ModAsSideEffect.rend(); 7192 MI != ME; ++MI) { 7193 UsageInfo &U = Self.UsageMap[MI->first]; 7194 auto &SideEffectUsage = U.Uses[UK_ModAsSideEffect]; 7195 Self.addUsage(U, MI->first, SideEffectUsage.Use, UK_ModAsValue); 7196 SideEffectUsage = MI->second; 7197 } 7198 Self.ModAsSideEffect = OldModAsSideEffect; 7199 } 7200 7201 SequenceChecker &Self; 7202 SmallVector<std::pair<Object, Usage>, 4> ModAsSideEffect; 7203 SmallVectorImpl<std::pair<Object, Usage> > *OldModAsSideEffect; 7204 }; 7205 7206 /// RAII object wrapping the visitation of a subexpression which we might 7207 /// choose to evaluate as a constant. If any subexpression is evaluated and 7208 /// found to be non-constant, this allows us to suppress the evaluation of 7209 /// the outer expression. 7210 class EvaluationTracker { 7211 public: 7212 EvaluationTracker(SequenceChecker &Self) 7213 : Self(Self), Prev(Self.EvalTracker), EvalOK(true) { 7214 Self.EvalTracker = this; 7215 } 7216 ~EvaluationTracker() { 7217 Self.EvalTracker = Prev; 7218 if (Prev) 7219 Prev->EvalOK &= EvalOK; 7220 } 7221 7222 bool evaluate(const Expr *E, bool &Result) { 7223 if (!EvalOK || E->isValueDependent()) 7224 return false; 7225 EvalOK = E->EvaluateAsBooleanCondition(Result, Self.SemaRef.Context); 7226 return EvalOK; 7227 } 7228 7229 private: 7230 SequenceChecker &Self; 7231 EvaluationTracker *Prev; 7232 bool EvalOK; 7233 } *EvalTracker; 7234 7235 /// \brief Find the object which is produced by the specified expression, 7236 /// if any. 7237 Object getObject(Expr *E, bool Mod) const { 7238 E = E->IgnoreParenCasts(); 7239 if (UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) { 7240 if (Mod && (UO->getOpcode() == UO_PreInc || UO->getOpcode() == UO_PreDec)) 7241 return getObject(UO->getSubExpr(), Mod); 7242 } else if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) { 7243 if (BO->getOpcode() == BO_Comma) 7244 return getObject(BO->getRHS(), Mod); 7245 if (Mod && BO->isAssignmentOp()) 7246 return getObject(BO->getLHS(), Mod); 7247 } else if (MemberExpr *ME = dyn_cast<MemberExpr>(E)) { 7248 // FIXME: Check for more interesting cases, like "x.n = ++x.n". 7249 if (isa<CXXThisExpr>(ME->getBase()->IgnoreParenCasts())) 7250 return ME->getMemberDecl(); 7251 } else if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) 7252 // FIXME: If this is a reference, map through to its value. 7253 return DRE->getDecl(); 7254 return nullptr; 7255 } 7256 7257 /// \brief Note that an object was modified or used by an expression. 7258 void addUsage(UsageInfo &UI, Object O, Expr *Ref, UsageKind UK) { 7259 Usage &U = UI.Uses[UK]; 7260 if (!U.Use || !Tree.isUnsequenced(Region, U.Seq)) { 7261 if (UK == UK_ModAsSideEffect && ModAsSideEffect) 7262 ModAsSideEffect->push_back(std::make_pair(O, U)); 7263 U.Use = Ref; 7264 U.Seq = Region; 7265 } 7266 } 7267 /// \brief Check whether a modification or use conflicts with a prior usage. 7268 void checkUsage(Object O, UsageInfo &UI, Expr *Ref, UsageKind OtherKind, 7269 bool IsModMod) { 7270 if (UI.Diagnosed) 7271 return; 7272 7273 const Usage &U = UI.Uses[OtherKind]; 7274 if (!U.Use || !Tree.isUnsequenced(Region, U.Seq)) 7275 return; 7276 7277 Expr *Mod = U.Use; 7278 Expr *ModOrUse = Ref; 7279 if (OtherKind == UK_Use) 7280 std::swap(Mod, ModOrUse); 7281 7282 SemaRef.Diag(Mod->getExprLoc(), 7283 IsModMod ? diag::warn_unsequenced_mod_mod 7284 : diag::warn_unsequenced_mod_use) 7285 << O << SourceRange(ModOrUse->getExprLoc()); 7286 UI.Diagnosed = true; 7287 } 7288 7289 void notePreUse(Object O, Expr *Use) { 7290 UsageInfo &U = UsageMap[O]; 7291 // Uses conflict with other modifications. 7292 checkUsage(O, U, Use, UK_ModAsValue, false); 7293 } 7294 void notePostUse(Object O, Expr *Use) { 7295 UsageInfo &U = UsageMap[O]; 7296 checkUsage(O, U, Use, UK_ModAsSideEffect, false); 7297 addUsage(U, O, Use, UK_Use); 7298 } 7299 7300 void notePreMod(Object O, Expr *Mod) { 7301 UsageInfo &U = UsageMap[O]; 7302 // Modifications conflict with other modifications and with uses. 7303 checkUsage(O, U, Mod, UK_ModAsValue, true); 7304 checkUsage(O, U, Mod, UK_Use, false); 7305 } 7306 void notePostMod(Object O, Expr *Use, UsageKind UK) { 7307 UsageInfo &U = UsageMap[O]; 7308 checkUsage(O, U, Use, UK_ModAsSideEffect, true); 7309 addUsage(U, O, Use, UK); 7310 } 7311 7312 public: 7313 SequenceChecker(Sema &S, Expr *E, SmallVectorImpl<Expr *> &WorkList) 7314 : Base(S.Context), SemaRef(S), Region(Tree.root()), 7315 ModAsSideEffect(nullptr), WorkList(WorkList), EvalTracker(nullptr) { 7316 Visit(E); 7317 } 7318 7319 void VisitStmt(Stmt *S) { 7320 // Skip all statements which aren't expressions for now. 7321 } 7322 7323 void VisitExpr(Expr *E) { 7324 // By default, just recurse to evaluated subexpressions. 7325 Base::VisitStmt(E); 7326 } 7327 7328 void VisitCastExpr(CastExpr *E) { 7329 Object O = Object(); 7330 if (E->getCastKind() == CK_LValueToRValue) 7331 O = getObject(E->getSubExpr(), false); 7332 7333 if (O) 7334 notePreUse(O, E); 7335 VisitExpr(E); 7336 if (O) 7337 notePostUse(O, E); 7338 } 7339 7340 void VisitBinComma(BinaryOperator *BO) { 7341 // C++11 [expr.comma]p1: 7342 // Every value computation and side effect associated with the left 7343 // expression is sequenced before every value computation and side 7344 // effect associated with the right expression. 7345 SequenceTree::Seq LHS = Tree.allocate(Region); 7346 SequenceTree::Seq RHS = Tree.allocate(Region); 7347 SequenceTree::Seq OldRegion = Region; 7348 7349 { 7350 SequencedSubexpression SeqLHS(*this); 7351 Region = LHS; 7352 Visit(BO->getLHS()); 7353 } 7354 7355 Region = RHS; 7356 Visit(BO->getRHS()); 7357 7358 Region = OldRegion; 7359 7360 // Forget that LHS and RHS are sequenced. They are both unsequenced 7361 // with respect to other stuff. 7362 Tree.merge(LHS); 7363 Tree.merge(RHS); 7364 } 7365 7366 void VisitBinAssign(BinaryOperator *BO) { 7367 // The modification is sequenced after the value computation of the LHS 7368 // and RHS, so check it before inspecting the operands and update the 7369 // map afterwards. 7370 Object O = getObject(BO->getLHS(), true); 7371 if (!O) 7372 return VisitExpr(BO); 7373 7374 notePreMod(O, BO); 7375 7376 // C++11 [expr.ass]p7: 7377 // E1 op= E2 is equivalent to E1 = E1 op E2, except that E1 is evaluated 7378 // only once. 7379 // 7380 // Therefore, for a compound assignment operator, O is considered used 7381 // everywhere except within the evaluation of E1 itself. 7382 if (isa<CompoundAssignOperator>(BO)) 7383 notePreUse(O, BO); 7384 7385 Visit(BO->getLHS()); 7386 7387 if (isa<CompoundAssignOperator>(BO)) 7388 notePostUse(O, BO); 7389 7390 Visit(BO->getRHS()); 7391 7392 // C++11 [expr.ass]p1: 7393 // the assignment is sequenced [...] before the value computation of the 7394 // assignment expression. 7395 // C11 6.5.16/3 has no such rule. 7396 notePostMod(O, BO, SemaRef.getLangOpts().CPlusPlus ? UK_ModAsValue 7397 : UK_ModAsSideEffect); 7398 } 7399 void VisitCompoundAssignOperator(CompoundAssignOperator *CAO) { 7400 VisitBinAssign(CAO); 7401 } 7402 7403 void VisitUnaryPreInc(UnaryOperator *UO) { VisitUnaryPreIncDec(UO); } 7404 void VisitUnaryPreDec(UnaryOperator *UO) { VisitUnaryPreIncDec(UO); } 7405 void VisitUnaryPreIncDec(UnaryOperator *UO) { 7406 Object O = getObject(UO->getSubExpr(), true); 7407 if (!O) 7408 return VisitExpr(UO); 7409 7410 notePreMod(O, UO); 7411 Visit(UO->getSubExpr()); 7412 // C++11 [expr.pre.incr]p1: 7413 // the expression ++x is equivalent to x+=1 7414 notePostMod(O, UO, SemaRef.getLangOpts().CPlusPlus ? UK_ModAsValue 7415 : UK_ModAsSideEffect); 7416 } 7417 7418 void VisitUnaryPostInc(UnaryOperator *UO) { VisitUnaryPostIncDec(UO); } 7419 void VisitUnaryPostDec(UnaryOperator *UO) { VisitUnaryPostIncDec(UO); } 7420 void VisitUnaryPostIncDec(UnaryOperator *UO) { 7421 Object O = getObject(UO->getSubExpr(), true); 7422 if (!O) 7423 return VisitExpr(UO); 7424 7425 notePreMod(O, UO); 7426 Visit(UO->getSubExpr()); 7427 notePostMod(O, UO, UK_ModAsSideEffect); 7428 } 7429 7430 /// Don't visit the RHS of '&&' or '||' if it might not be evaluated. 7431 void VisitBinLOr(BinaryOperator *BO) { 7432 // The side-effects of the LHS of an '&&' are sequenced before the 7433 // value computation of the RHS, and hence before the value computation 7434 // of the '&&' itself, unless the LHS evaluates to zero. We treat them 7435 // as if they were unconditionally sequenced. 7436 EvaluationTracker Eval(*this); 7437 { 7438 SequencedSubexpression Sequenced(*this); 7439 Visit(BO->getLHS()); 7440 } 7441 7442 bool Result; 7443 if (Eval.evaluate(BO->getLHS(), Result)) { 7444 if (!Result) 7445 Visit(BO->getRHS()); 7446 } else { 7447 // Check for unsequenced operations in the RHS, treating it as an 7448 // entirely separate evaluation. 7449 // 7450 // FIXME: If there are operations in the RHS which are unsequenced 7451 // with respect to operations outside the RHS, and those operations 7452 // are unconditionally evaluated, diagnose them. 7453 WorkList.push_back(BO->getRHS()); 7454 } 7455 } 7456 void VisitBinLAnd(BinaryOperator *BO) { 7457 EvaluationTracker Eval(*this); 7458 { 7459 SequencedSubexpression Sequenced(*this); 7460 Visit(BO->getLHS()); 7461 } 7462 7463 bool Result; 7464 if (Eval.evaluate(BO->getLHS(), Result)) { 7465 if (Result) 7466 Visit(BO->getRHS()); 7467 } else { 7468 WorkList.push_back(BO->getRHS()); 7469 } 7470 } 7471 7472 // Only visit the condition, unless we can be sure which subexpression will 7473 // be chosen. 7474 void VisitAbstractConditionalOperator(AbstractConditionalOperator *CO) { 7475 EvaluationTracker Eval(*this); 7476 { 7477 SequencedSubexpression Sequenced(*this); 7478 Visit(CO->getCond()); 7479 } 7480 7481 bool Result; 7482 if (Eval.evaluate(CO->getCond(), Result)) 7483 Visit(Result ? CO->getTrueExpr() : CO->getFalseExpr()); 7484 else { 7485 WorkList.push_back(CO->getTrueExpr()); 7486 WorkList.push_back(CO->getFalseExpr()); 7487 } 7488 } 7489 7490 void VisitCallExpr(CallExpr *CE) { 7491 // C++11 [intro.execution]p15: 7492 // When calling a function [...], every value computation and side effect 7493 // associated with any argument expression, or with the postfix expression 7494 // designating the called function, is sequenced before execution of every 7495 // expression or statement in the body of the function [and thus before 7496 // the value computation of its result]. 7497 SequencedSubexpression Sequenced(*this); 7498 Base::VisitCallExpr(CE); 7499 7500 // FIXME: CXXNewExpr and CXXDeleteExpr implicitly call functions. 7501 } 7502 7503 void VisitCXXConstructExpr(CXXConstructExpr *CCE) { 7504 // This is a call, so all subexpressions are sequenced before the result. 7505 SequencedSubexpression Sequenced(*this); 7506 7507 if (!CCE->isListInitialization()) 7508 return VisitExpr(CCE); 7509 7510 // In C++11, list initializations are sequenced. 7511 SmallVector<SequenceTree::Seq, 32> Elts; 7512 SequenceTree::Seq Parent = Region; 7513 for (CXXConstructExpr::arg_iterator I = CCE->arg_begin(), 7514 E = CCE->arg_end(); 7515 I != E; ++I) { 7516 Region = Tree.allocate(Parent); 7517 Elts.push_back(Region); 7518 Visit(*I); 7519 } 7520 7521 // Forget that the initializers are sequenced. 7522 Region = Parent; 7523 for (unsigned I = 0; I < Elts.size(); ++I) 7524 Tree.merge(Elts[I]); 7525 } 7526 7527 void VisitInitListExpr(InitListExpr *ILE) { 7528 if (!SemaRef.getLangOpts().CPlusPlus11) 7529 return VisitExpr(ILE); 7530 7531 // In C++11, list initializations are sequenced. 7532 SmallVector<SequenceTree::Seq, 32> Elts; 7533 SequenceTree::Seq Parent = Region; 7534 for (unsigned I = 0; I < ILE->getNumInits(); ++I) { 7535 Expr *E = ILE->getInit(I); 7536 if (!E) continue; 7537 Region = Tree.allocate(Parent); 7538 Elts.push_back(Region); 7539 Visit(E); 7540 } 7541 7542 // Forget that the initializers are sequenced. 7543 Region = Parent; 7544 for (unsigned I = 0; I < Elts.size(); ++I) 7545 Tree.merge(Elts[I]); 7546 } 7547 }; 7548 } 7549 7550 void Sema::CheckUnsequencedOperations(Expr *E) { 7551 SmallVector<Expr *, 8> WorkList; 7552 WorkList.push_back(E); 7553 while (!WorkList.empty()) { 7554 Expr *Item = WorkList.pop_back_val(); 7555 SequenceChecker(*this, Item, WorkList); 7556 } 7557 } 7558 7559 void Sema::CheckCompletedExpr(Expr *E, SourceLocation CheckLoc, 7560 bool IsConstexpr) { 7561 CheckImplicitConversions(E, CheckLoc); 7562 CheckUnsequencedOperations(E); 7563 if (!IsConstexpr && !E->isValueDependent()) 7564 CheckForIntOverflow(E); 7565 } 7566 7567 void Sema::CheckBitFieldInitialization(SourceLocation InitLoc, 7568 FieldDecl *BitField, 7569 Expr *Init) { 7570 (void) AnalyzeBitFieldAssignment(*this, BitField, Init, InitLoc); 7571 } 7572 7573 /// CheckParmsForFunctionDef - Check that the parameters of the given 7574 /// function are appropriate for the definition of a function. This 7575 /// takes care of any checks that cannot be performed on the 7576 /// declaration itself, e.g., that the types of each of the function 7577 /// parameters are complete. 7578 bool Sema::CheckParmsForFunctionDef(ParmVarDecl *const *P, 7579 ParmVarDecl *const *PEnd, 7580 bool CheckParameterNames) { 7581 bool HasInvalidParm = false; 7582 for (; P != PEnd; ++P) { 7583 ParmVarDecl *Param = *P; 7584 7585 // C99 6.7.5.3p4: the parameters in a parameter type list in a 7586 // function declarator that is part of a function definition of 7587 // that function shall not have incomplete type. 7588 // 7589 // This is also C++ [dcl.fct]p6. 7590 if (!Param->isInvalidDecl() && 7591 RequireCompleteType(Param->getLocation(), Param->getType(), 7592 diag::err_typecheck_decl_incomplete_type)) { 7593 Param->setInvalidDecl(); 7594 HasInvalidParm = true; 7595 } 7596 7597 // C99 6.9.1p5: If the declarator includes a parameter type list, the 7598 // declaration of each parameter shall include an identifier. 7599 if (CheckParameterNames && 7600 Param->getIdentifier() == nullptr && 7601 !Param->isImplicit() && 7602 !getLangOpts().CPlusPlus) 7603 Diag(Param->getLocation(), diag::err_parameter_name_omitted); 7604 7605 // C99 6.7.5.3p12: 7606 // If the function declarator is not part of a definition of that 7607 // function, parameters may have incomplete type and may use the [*] 7608 // notation in their sequences of declarator specifiers to specify 7609 // variable length array types. 7610 QualType PType = Param->getOriginalType(); 7611 while (const ArrayType *AT = Context.getAsArrayType(PType)) { 7612 if (AT->getSizeModifier() == ArrayType::Star) { 7613 // FIXME: This diagnostic should point the '[*]' if source-location 7614 // information is added for it. 7615 Diag(Param->getLocation(), diag::err_array_star_in_function_definition); 7616 break; 7617 } 7618 PType= AT->getElementType(); 7619 } 7620 7621 // MSVC destroys objects passed by value in the callee. Therefore a 7622 // function definition which takes such a parameter must be able to call the 7623 // object's destructor. However, we don't perform any direct access check 7624 // on the dtor. 7625 if (getLangOpts().CPlusPlus && Context.getTargetInfo() 7626 .getCXXABI() 7627 .areArgsDestroyedLeftToRightInCallee()) { 7628 if (!Param->isInvalidDecl()) { 7629 if (const RecordType *RT = Param->getType()->getAs<RecordType>()) { 7630 CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(RT->getDecl()); 7631 if (!ClassDecl->isInvalidDecl() && 7632 !ClassDecl->hasIrrelevantDestructor() && 7633 !ClassDecl->isDependentContext()) { 7634 CXXDestructorDecl *Destructor = LookupDestructor(ClassDecl); 7635 MarkFunctionReferenced(Param->getLocation(), Destructor); 7636 DiagnoseUseOfDecl(Destructor, Param->getLocation()); 7637 } 7638 } 7639 } 7640 } 7641 } 7642 7643 return HasInvalidParm; 7644 } 7645 7646 /// CheckCastAlign - Implements -Wcast-align, which warns when a 7647 /// pointer cast increases the alignment requirements. 7648 void Sema::CheckCastAlign(Expr *Op, QualType T, SourceRange TRange) { 7649 // This is actually a lot of work to potentially be doing on every 7650 // cast; don't do it if we're ignoring -Wcast_align (as is the default). 7651 if (getDiagnostics().isIgnored(diag::warn_cast_align, TRange.getBegin())) 7652 return; 7653 7654 // Ignore dependent types. 7655 if (T->isDependentType() || Op->getType()->isDependentType()) 7656 return; 7657 7658 // Require that the destination be a pointer type. 7659 const PointerType *DestPtr = T->getAs<PointerType>(); 7660 if (!DestPtr) return; 7661 7662 // If the destination has alignment 1, we're done. 7663 QualType DestPointee = DestPtr->getPointeeType(); 7664 if (DestPointee->isIncompleteType()) return; 7665 CharUnits DestAlign = Context.getTypeAlignInChars(DestPointee); 7666 if (DestAlign.isOne()) return; 7667 7668 // Require that the source be a pointer type. 7669 const PointerType *SrcPtr = Op->getType()->getAs<PointerType>(); 7670 if (!SrcPtr) return; 7671 QualType SrcPointee = SrcPtr->getPointeeType(); 7672 7673 // Whitelist casts from cv void*. We already implicitly 7674 // whitelisted casts to cv void*, since they have alignment 1. 7675 // Also whitelist casts involving incomplete types, which implicitly 7676 // includes 'void'. 7677 if (SrcPointee->isIncompleteType()) return; 7678 7679 CharUnits SrcAlign = Context.getTypeAlignInChars(SrcPointee); 7680 if (SrcAlign >= DestAlign) return; 7681 7682 Diag(TRange.getBegin(), diag::warn_cast_align) 7683 << Op->getType() << T 7684 << static_cast<unsigned>(SrcAlign.getQuantity()) 7685 << static_cast<unsigned>(DestAlign.getQuantity()) 7686 << TRange << Op->getSourceRange(); 7687 } 7688 7689 static const Type* getElementType(const Expr *BaseExpr) { 7690 const Type* EltType = BaseExpr->getType().getTypePtr(); 7691 if (EltType->isAnyPointerType()) 7692 return EltType->getPointeeType().getTypePtr(); 7693 else if (EltType->isArrayType()) 7694 return EltType->getBaseElementTypeUnsafe(); 7695 return EltType; 7696 } 7697 7698 /// \brief Check whether this array fits the idiom of a size-one tail padded 7699 /// array member of a struct. 7700 /// 7701 /// We avoid emitting out-of-bounds access warnings for such arrays as they are 7702 /// commonly used to emulate flexible arrays in C89 code. 7703 static bool IsTailPaddedMemberArray(Sema &S, llvm::APInt Size, 7704 const NamedDecl *ND) { 7705 if (Size != 1 || !ND) return false; 7706 7707 const FieldDecl *FD = dyn_cast<FieldDecl>(ND); 7708 if (!FD) return false; 7709 7710 // Don't consider sizes resulting from macro expansions or template argument 7711 // substitution to form C89 tail-padded arrays. 7712 7713 TypeSourceInfo *TInfo = FD->getTypeSourceInfo(); 7714 while (TInfo) { 7715 TypeLoc TL = TInfo->getTypeLoc(); 7716 // Look through typedefs. 7717 if (TypedefTypeLoc TTL = TL.getAs<TypedefTypeLoc>()) { 7718 const TypedefNameDecl *TDL = TTL.getTypedefNameDecl(); 7719 TInfo = TDL->getTypeSourceInfo(); 7720 continue; 7721 } 7722 if (ConstantArrayTypeLoc CTL = TL.getAs<ConstantArrayTypeLoc>()) { 7723 const Expr *SizeExpr = dyn_cast<IntegerLiteral>(CTL.getSizeExpr()); 7724 if (!SizeExpr || SizeExpr->getExprLoc().isMacroID()) 7725 return false; 7726 } 7727 break; 7728 } 7729 7730 const RecordDecl *RD = dyn_cast<RecordDecl>(FD->getDeclContext()); 7731 if (!RD) return false; 7732 if (RD->isUnion()) return false; 7733 if (const CXXRecordDecl *CRD = dyn_cast<CXXRecordDecl>(RD)) { 7734 if (!CRD->isStandardLayout()) return false; 7735 } 7736 7737 // See if this is the last field decl in the record. 7738 const Decl *D = FD; 7739 while ((D = D->getNextDeclInContext())) 7740 if (isa<FieldDecl>(D)) 7741 return false; 7742 return true; 7743 } 7744 7745 void Sema::CheckArrayAccess(const Expr *BaseExpr, const Expr *IndexExpr, 7746 const ArraySubscriptExpr *ASE, 7747 bool AllowOnePastEnd, bool IndexNegated) { 7748 IndexExpr = IndexExpr->IgnoreParenImpCasts(); 7749 if (IndexExpr->isValueDependent()) 7750 return; 7751 7752 const Type *EffectiveType = getElementType(BaseExpr); 7753 BaseExpr = BaseExpr->IgnoreParenCasts(); 7754 const ConstantArrayType *ArrayTy = 7755 Context.getAsConstantArrayType(BaseExpr->getType()); 7756 if (!ArrayTy) 7757 return; 7758 7759 llvm::APSInt index; 7760 if (!IndexExpr->EvaluateAsInt(index, Context)) 7761 return; 7762 if (IndexNegated) 7763 index = -index; 7764 7765 const NamedDecl *ND = nullptr; 7766 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(BaseExpr)) 7767 ND = dyn_cast<NamedDecl>(DRE->getDecl()); 7768 if (const MemberExpr *ME = dyn_cast<MemberExpr>(BaseExpr)) 7769 ND = dyn_cast<NamedDecl>(ME->getMemberDecl()); 7770 7771 if (index.isUnsigned() || !index.isNegative()) { 7772 llvm::APInt size = ArrayTy->getSize(); 7773 if (!size.isStrictlyPositive()) 7774 return; 7775 7776 const Type* BaseType = getElementType(BaseExpr); 7777 if (BaseType != EffectiveType) { 7778 // Make sure we're comparing apples to apples when comparing index to size 7779 uint64_t ptrarith_typesize = Context.getTypeSize(EffectiveType); 7780 uint64_t array_typesize = Context.getTypeSize(BaseType); 7781 // Handle ptrarith_typesize being zero, such as when casting to void* 7782 if (!ptrarith_typesize) ptrarith_typesize = 1; 7783 if (ptrarith_typesize != array_typesize) { 7784 // There's a cast to a different size type involved 7785 uint64_t ratio = array_typesize / ptrarith_typesize; 7786 // TODO: Be smarter about handling cases where array_typesize is not a 7787 // multiple of ptrarith_typesize 7788 if (ptrarith_typesize * ratio == array_typesize) 7789 size *= llvm::APInt(size.getBitWidth(), ratio); 7790 } 7791 } 7792 7793 if (size.getBitWidth() > index.getBitWidth()) 7794 index = index.zext(size.getBitWidth()); 7795 else if (size.getBitWidth() < index.getBitWidth()) 7796 size = size.zext(index.getBitWidth()); 7797 7798 // For array subscripting the index must be less than size, but for pointer 7799 // arithmetic also allow the index (offset) to be equal to size since 7800 // computing the next address after the end of the array is legal and 7801 // commonly done e.g. in C++ iterators and range-based for loops. 7802 if (AllowOnePastEnd ? index.ule(size) : index.ult(size)) 7803 return; 7804 7805 // Also don't warn for arrays of size 1 which are members of some 7806 // structure. These are often used to approximate flexible arrays in C89 7807 // code. 7808 if (IsTailPaddedMemberArray(*this, size, ND)) 7809 return; 7810 7811 // Suppress the warning if the subscript expression (as identified by the 7812 // ']' location) and the index expression are both from macro expansions 7813 // within a system header. 7814 if (ASE) { 7815 SourceLocation RBracketLoc = SourceMgr.getSpellingLoc( 7816 ASE->getRBracketLoc()); 7817 if (SourceMgr.isInSystemHeader(RBracketLoc)) { 7818 SourceLocation IndexLoc = SourceMgr.getSpellingLoc( 7819 IndexExpr->getLocStart()); 7820 if (SourceMgr.isWrittenInSameFile(RBracketLoc, IndexLoc)) 7821 return; 7822 } 7823 } 7824 7825 unsigned DiagID = diag::warn_ptr_arith_exceeds_bounds; 7826 if (ASE) 7827 DiagID = diag::warn_array_index_exceeds_bounds; 7828 7829 DiagRuntimeBehavior(BaseExpr->getLocStart(), BaseExpr, 7830 PDiag(DiagID) << index.toString(10, true) 7831 << size.toString(10, true) 7832 << (unsigned)size.getLimitedValue(~0U) 7833 << IndexExpr->getSourceRange()); 7834 } else { 7835 unsigned DiagID = diag::warn_array_index_precedes_bounds; 7836 if (!ASE) { 7837 DiagID = diag::warn_ptr_arith_precedes_bounds; 7838 if (index.isNegative()) index = -index; 7839 } 7840 7841 DiagRuntimeBehavior(BaseExpr->getLocStart(), BaseExpr, 7842 PDiag(DiagID) << index.toString(10, true) 7843 << IndexExpr->getSourceRange()); 7844 } 7845 7846 if (!ND) { 7847 // Try harder to find a NamedDecl to point at in the note. 7848 while (const ArraySubscriptExpr *ASE = 7849 dyn_cast<ArraySubscriptExpr>(BaseExpr)) 7850 BaseExpr = ASE->getBase()->IgnoreParenCasts(); 7851 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(BaseExpr)) 7852 ND = dyn_cast<NamedDecl>(DRE->getDecl()); 7853 if (const MemberExpr *ME = dyn_cast<MemberExpr>(BaseExpr)) 7854 ND = dyn_cast<NamedDecl>(ME->getMemberDecl()); 7855 } 7856 7857 if (ND) 7858 DiagRuntimeBehavior(ND->getLocStart(), BaseExpr, 7859 PDiag(diag::note_array_index_out_of_bounds) 7860 << ND->getDeclName()); 7861 } 7862 7863 void Sema::CheckArrayAccess(const Expr *expr) { 7864 int AllowOnePastEnd = 0; 7865 while (expr) { 7866 expr = expr->IgnoreParenImpCasts(); 7867 switch (expr->getStmtClass()) { 7868 case Stmt::ArraySubscriptExprClass: { 7869 const ArraySubscriptExpr *ASE = cast<ArraySubscriptExpr>(expr); 7870 CheckArrayAccess(ASE->getBase(), ASE->getIdx(), ASE, 7871 AllowOnePastEnd > 0); 7872 return; 7873 } 7874 case Stmt::UnaryOperatorClass: { 7875 // Only unwrap the * and & unary operators 7876 const UnaryOperator *UO = cast<UnaryOperator>(expr); 7877 expr = UO->getSubExpr(); 7878 switch (UO->getOpcode()) { 7879 case UO_AddrOf: 7880 AllowOnePastEnd++; 7881 break; 7882 case UO_Deref: 7883 AllowOnePastEnd--; 7884 break; 7885 default: 7886 return; 7887 } 7888 break; 7889 } 7890 case Stmt::ConditionalOperatorClass: { 7891 const ConditionalOperator *cond = cast<ConditionalOperator>(expr); 7892 if (const Expr *lhs = cond->getLHS()) 7893 CheckArrayAccess(lhs); 7894 if (const Expr *rhs = cond->getRHS()) 7895 CheckArrayAccess(rhs); 7896 return; 7897 } 7898 default: 7899 return; 7900 } 7901 } 7902 } 7903 7904 //===--- CHECK: Objective-C retain cycles ----------------------------------// 7905 7906 namespace { 7907 struct RetainCycleOwner { 7908 RetainCycleOwner() : Variable(nullptr), Indirect(false) {} 7909 VarDecl *Variable; 7910 SourceRange Range; 7911 SourceLocation Loc; 7912 bool Indirect; 7913 7914 void setLocsFrom(Expr *e) { 7915 Loc = e->getExprLoc(); 7916 Range = e->getSourceRange(); 7917 } 7918 }; 7919 } 7920 7921 /// Consider whether capturing the given variable can possibly lead to 7922 /// a retain cycle. 7923 static bool considerVariable(VarDecl *var, Expr *ref, RetainCycleOwner &owner) { 7924 // In ARC, it's captured strongly iff the variable has __strong 7925 // lifetime. In MRR, it's captured strongly if the variable is 7926 // __block and has an appropriate type. 7927 if (var->getType().getObjCLifetime() != Qualifiers::OCL_Strong) 7928 return false; 7929 7930 owner.Variable = var; 7931 if (ref) 7932 owner.setLocsFrom(ref); 7933 return true; 7934 } 7935 7936 static bool findRetainCycleOwner(Sema &S, Expr *e, RetainCycleOwner &owner) { 7937 while (true) { 7938 e = e->IgnoreParens(); 7939 if (CastExpr *cast = dyn_cast<CastExpr>(e)) { 7940 switch (cast->getCastKind()) { 7941 case CK_BitCast: 7942 case CK_LValueBitCast: 7943 case CK_LValueToRValue: 7944 case CK_ARCReclaimReturnedObject: 7945 e = cast->getSubExpr(); 7946 continue; 7947 7948 default: 7949 return false; 7950 } 7951 } 7952 7953 if (ObjCIvarRefExpr *ref = dyn_cast<ObjCIvarRefExpr>(e)) { 7954 ObjCIvarDecl *ivar = ref->getDecl(); 7955 if (ivar->getType().getObjCLifetime() != Qualifiers::OCL_Strong) 7956 return false; 7957 7958 // Try to find a retain cycle in the base. 7959 if (!findRetainCycleOwner(S, ref->getBase(), owner)) 7960 return false; 7961 7962 if (ref->isFreeIvar()) owner.setLocsFrom(ref); 7963 owner.Indirect = true; 7964 return true; 7965 } 7966 7967 if (DeclRefExpr *ref = dyn_cast<DeclRefExpr>(e)) { 7968 VarDecl *var = dyn_cast<VarDecl>(ref->getDecl()); 7969 if (!var) return false; 7970 return considerVariable(var, ref, owner); 7971 } 7972 7973 if (MemberExpr *member = dyn_cast<MemberExpr>(e)) { 7974 if (member->isArrow()) return false; 7975 7976 // Don't count this as an indirect ownership. 7977 e = member->getBase(); 7978 continue; 7979 } 7980 7981 if (PseudoObjectExpr *pseudo = dyn_cast<PseudoObjectExpr>(e)) { 7982 // Only pay attention to pseudo-objects on property references. 7983 ObjCPropertyRefExpr *pre 7984 = dyn_cast<ObjCPropertyRefExpr>(pseudo->getSyntacticForm() 7985 ->IgnoreParens()); 7986 if (!pre) return false; 7987 if (pre->isImplicitProperty()) return false; 7988 ObjCPropertyDecl *property = pre->getExplicitProperty(); 7989 if (!property->isRetaining() && 7990 !(property->getPropertyIvarDecl() && 7991 property->getPropertyIvarDecl()->getType() 7992 .getObjCLifetime() == Qualifiers::OCL_Strong)) 7993 return false; 7994 7995 owner.Indirect = true; 7996 if (pre->isSuperReceiver()) { 7997 owner.Variable = S.getCurMethodDecl()->getSelfDecl(); 7998 if (!owner.Variable) 7999 return false; 8000 owner.Loc = pre->getLocation(); 8001 owner.Range = pre->getSourceRange(); 8002 return true; 8003 } 8004 e = const_cast<Expr*>(cast<OpaqueValueExpr>(pre->getBase()) 8005 ->getSourceExpr()); 8006 continue; 8007 } 8008 8009 // Array ivars? 8010 8011 return false; 8012 } 8013 } 8014 8015 namespace { 8016 struct FindCaptureVisitor : EvaluatedExprVisitor<FindCaptureVisitor> { 8017 FindCaptureVisitor(ASTContext &Context, VarDecl *variable) 8018 : EvaluatedExprVisitor<FindCaptureVisitor>(Context), 8019 Context(Context), Variable(variable), Capturer(nullptr), 8020 VarWillBeReased(false) {} 8021 ASTContext &Context; 8022 VarDecl *Variable; 8023 Expr *Capturer; 8024 bool VarWillBeReased; 8025 8026 void VisitDeclRefExpr(DeclRefExpr *ref) { 8027 if (ref->getDecl() == Variable && !Capturer) 8028 Capturer = ref; 8029 } 8030 8031 void VisitObjCIvarRefExpr(ObjCIvarRefExpr *ref) { 8032 if (Capturer) return; 8033 Visit(ref->getBase()); 8034 if (Capturer && ref->isFreeIvar()) 8035 Capturer = ref; 8036 } 8037 8038 void VisitBlockExpr(BlockExpr *block) { 8039 // Look inside nested blocks 8040 if (block->getBlockDecl()->capturesVariable(Variable)) 8041 Visit(block->getBlockDecl()->getBody()); 8042 } 8043 8044 void VisitOpaqueValueExpr(OpaqueValueExpr *OVE) { 8045 if (Capturer) return; 8046 if (OVE->getSourceExpr()) 8047 Visit(OVE->getSourceExpr()); 8048 } 8049 void VisitBinaryOperator(BinaryOperator *BinOp) { 8050 if (!Variable || VarWillBeReased || BinOp->getOpcode() != BO_Assign) 8051 return; 8052 Expr *LHS = BinOp->getLHS(); 8053 if (const DeclRefExpr *DRE = dyn_cast_or_null<DeclRefExpr>(LHS)) { 8054 if (DRE->getDecl() != Variable) 8055 return; 8056 if (Expr *RHS = BinOp->getRHS()) { 8057 RHS = RHS->IgnoreParenCasts(); 8058 llvm::APSInt Value; 8059 VarWillBeReased = 8060 (RHS && RHS->isIntegerConstantExpr(Value, Context) && Value == 0); 8061 } 8062 } 8063 } 8064 }; 8065 } 8066 8067 /// Check whether the given argument is a block which captures a 8068 /// variable. 8069 static Expr *findCapturingExpr(Sema &S, Expr *e, RetainCycleOwner &owner) { 8070 assert(owner.Variable && owner.Loc.isValid()); 8071 8072 e = e->IgnoreParenCasts(); 8073 8074 // Look through [^{...} copy] and Block_copy(^{...}). 8075 if (ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(e)) { 8076 Selector Cmd = ME->getSelector(); 8077 if (Cmd.isUnarySelector() && Cmd.getNameForSlot(0) == "copy") { 8078 e = ME->getInstanceReceiver(); 8079 if (!e) 8080 return nullptr; 8081 e = e->IgnoreParenCasts(); 8082 } 8083 } else if (CallExpr *CE = dyn_cast<CallExpr>(e)) { 8084 if (CE->getNumArgs() == 1) { 8085 FunctionDecl *Fn = dyn_cast_or_null<FunctionDecl>(CE->getCalleeDecl()); 8086 if (Fn) { 8087 const IdentifierInfo *FnI = Fn->getIdentifier(); 8088 if (FnI && FnI->isStr("_Block_copy")) { 8089 e = CE->getArg(0)->IgnoreParenCasts(); 8090 } 8091 } 8092 } 8093 } 8094 8095 BlockExpr *block = dyn_cast<BlockExpr>(e); 8096 if (!block || !block->getBlockDecl()->capturesVariable(owner.Variable)) 8097 return nullptr; 8098 8099 FindCaptureVisitor visitor(S.Context, owner.Variable); 8100 visitor.Visit(block->getBlockDecl()->getBody()); 8101 return visitor.VarWillBeReased ? nullptr : visitor.Capturer; 8102 } 8103 8104 static void diagnoseRetainCycle(Sema &S, Expr *capturer, 8105 RetainCycleOwner &owner) { 8106 assert(capturer); 8107 assert(owner.Variable && owner.Loc.isValid()); 8108 8109 S.Diag(capturer->getExprLoc(), diag::warn_arc_retain_cycle) 8110 << owner.Variable << capturer->getSourceRange(); 8111 S.Diag(owner.Loc, diag::note_arc_retain_cycle_owner) 8112 << owner.Indirect << owner.Range; 8113 } 8114 8115 /// Check for a keyword selector that starts with the word 'add' or 8116 /// 'set'. 8117 static bool isSetterLikeSelector(Selector sel) { 8118 if (sel.isUnarySelector()) return false; 8119 8120 StringRef str = sel.getNameForSlot(0); 8121 while (!str.empty() && str.front() == '_') str = str.substr(1); 8122 if (str.startswith("set")) 8123 str = str.substr(3); 8124 else if (str.startswith("add")) { 8125 // Specially whitelist 'addOperationWithBlock:'. 8126 if (sel.getNumArgs() == 1 && str.startswith("addOperationWithBlock")) 8127 return false; 8128 str = str.substr(3); 8129 } 8130 else 8131 return false; 8132 8133 if (str.empty()) return true; 8134 return !isLowercase(str.front()); 8135 } 8136 8137 /// Check a message send to see if it's likely to cause a retain cycle. 8138 void Sema::checkRetainCycles(ObjCMessageExpr *msg) { 8139 // Only check instance methods whose selector looks like a setter. 8140 if (!msg->isInstanceMessage() || !isSetterLikeSelector(msg->getSelector())) 8141 return; 8142 8143 // Try to find a variable that the receiver is strongly owned by. 8144 RetainCycleOwner owner; 8145 if (msg->getReceiverKind() == ObjCMessageExpr::Instance) { 8146 if (!findRetainCycleOwner(*this, msg->getInstanceReceiver(), owner)) 8147 return; 8148 } else { 8149 assert(msg->getReceiverKind() == ObjCMessageExpr::SuperInstance); 8150 owner.Variable = getCurMethodDecl()->getSelfDecl(); 8151 owner.Loc = msg->getSuperLoc(); 8152 owner.Range = msg->getSuperLoc(); 8153 } 8154 8155 // Check whether the receiver is captured by any of the arguments. 8156 for (unsigned i = 0, e = msg->getNumArgs(); i != e; ++i) 8157 if (Expr *capturer = findCapturingExpr(*this, msg->getArg(i), owner)) 8158 return diagnoseRetainCycle(*this, capturer, owner); 8159 } 8160 8161 /// Check a property assign to see if it's likely to cause a retain cycle. 8162 void Sema::checkRetainCycles(Expr *receiver, Expr *argument) { 8163 RetainCycleOwner owner; 8164 if (!findRetainCycleOwner(*this, receiver, owner)) 8165 return; 8166 8167 if (Expr *capturer = findCapturingExpr(*this, argument, owner)) 8168 diagnoseRetainCycle(*this, capturer, owner); 8169 } 8170 8171 void Sema::checkRetainCycles(VarDecl *Var, Expr *Init) { 8172 RetainCycleOwner Owner; 8173 if (!considerVariable(Var, /*DeclRefExpr=*/nullptr, Owner)) 8174 return; 8175 8176 // Because we don't have an expression for the variable, we have to set the 8177 // location explicitly here. 8178 Owner.Loc = Var->getLocation(); 8179 Owner.Range = Var->getSourceRange(); 8180 8181 if (Expr *Capturer = findCapturingExpr(*this, Init, Owner)) 8182 diagnoseRetainCycle(*this, Capturer, Owner); 8183 } 8184 8185 static bool checkUnsafeAssignLiteral(Sema &S, SourceLocation Loc, 8186 Expr *RHS, bool isProperty) { 8187 // Check if RHS is an Objective-C object literal, which also can get 8188 // immediately zapped in a weak reference. Note that we explicitly 8189 // allow ObjCStringLiterals, since those are designed to never really die. 8190 RHS = RHS->IgnoreParenImpCasts(); 8191 8192 // This enum needs to match with the 'select' in 8193 // warn_objc_arc_literal_assign (off-by-1). 8194 Sema::ObjCLiteralKind Kind = S.CheckLiteralKind(RHS); 8195 if (Kind == Sema::LK_String || Kind == Sema::LK_None) 8196 return false; 8197 8198 S.Diag(Loc, diag::warn_arc_literal_assign) 8199 << (unsigned) Kind 8200 << (isProperty ? 0 : 1) 8201 << RHS->getSourceRange(); 8202 8203 return true; 8204 } 8205 8206 static bool checkUnsafeAssignObject(Sema &S, SourceLocation Loc, 8207 Qualifiers::ObjCLifetime LT, 8208 Expr *RHS, bool isProperty) { 8209 // Strip off any implicit cast added to get to the one ARC-specific. 8210 while (ImplicitCastExpr *cast = dyn_cast<ImplicitCastExpr>(RHS)) { 8211 if (cast->getCastKind() == CK_ARCConsumeObject) { 8212 S.Diag(Loc, diag::warn_arc_retained_assign) 8213 << (LT == Qualifiers::OCL_ExplicitNone) 8214 << (isProperty ? 0 : 1) 8215 << RHS->getSourceRange(); 8216 return true; 8217 } 8218 RHS = cast->getSubExpr(); 8219 } 8220 8221 if (LT == Qualifiers::OCL_Weak && 8222 checkUnsafeAssignLiteral(S, Loc, RHS, isProperty)) 8223 return true; 8224 8225 return false; 8226 } 8227 8228 bool Sema::checkUnsafeAssigns(SourceLocation Loc, 8229 QualType LHS, Expr *RHS) { 8230 Qualifiers::ObjCLifetime LT = LHS.getObjCLifetime(); 8231 8232 if (LT != Qualifiers::OCL_Weak && LT != Qualifiers::OCL_ExplicitNone) 8233 return false; 8234 8235 if (checkUnsafeAssignObject(*this, Loc, LT, RHS, false)) 8236 return true; 8237 8238 return false; 8239 } 8240 8241 void Sema::checkUnsafeExprAssigns(SourceLocation Loc, 8242 Expr *LHS, Expr *RHS) { 8243 QualType LHSType; 8244 // PropertyRef on LHS type need be directly obtained from 8245 // its declaration as it has a PseudoType. 8246 ObjCPropertyRefExpr *PRE 8247 = dyn_cast<ObjCPropertyRefExpr>(LHS->IgnoreParens()); 8248 if (PRE && !PRE->isImplicitProperty()) { 8249 const ObjCPropertyDecl *PD = PRE->getExplicitProperty(); 8250 if (PD) 8251 LHSType = PD->getType(); 8252 } 8253 8254 if (LHSType.isNull()) 8255 LHSType = LHS->getType(); 8256 8257 Qualifiers::ObjCLifetime LT = LHSType.getObjCLifetime(); 8258 8259 if (LT == Qualifiers::OCL_Weak) { 8260 if (!Diags.isIgnored(diag::warn_arc_repeated_use_of_weak, Loc)) 8261 getCurFunction()->markSafeWeakUse(LHS); 8262 } 8263 8264 if (checkUnsafeAssigns(Loc, LHSType, RHS)) 8265 return; 8266 8267 // FIXME. Check for other life times. 8268 if (LT != Qualifiers::OCL_None) 8269 return; 8270 8271 if (PRE) { 8272 if (PRE->isImplicitProperty()) 8273 return; 8274 const ObjCPropertyDecl *PD = PRE->getExplicitProperty(); 8275 if (!PD) 8276 return; 8277 8278 unsigned Attributes = PD->getPropertyAttributes(); 8279 if (Attributes & ObjCPropertyDecl::OBJC_PR_assign) { 8280 // when 'assign' attribute was not explicitly specified 8281 // by user, ignore it and rely on property type itself 8282 // for lifetime info. 8283 unsigned AsWrittenAttr = PD->getPropertyAttributesAsWritten(); 8284 if (!(AsWrittenAttr & ObjCPropertyDecl::OBJC_PR_assign) && 8285 LHSType->isObjCRetainableType()) 8286 return; 8287 8288 while (ImplicitCastExpr *cast = dyn_cast<ImplicitCastExpr>(RHS)) { 8289 if (cast->getCastKind() == CK_ARCConsumeObject) { 8290 Diag(Loc, diag::warn_arc_retained_property_assign) 8291 << RHS->getSourceRange(); 8292 return; 8293 } 8294 RHS = cast->getSubExpr(); 8295 } 8296 } 8297 else if (Attributes & ObjCPropertyDecl::OBJC_PR_weak) { 8298 if (checkUnsafeAssignObject(*this, Loc, Qualifiers::OCL_Weak, RHS, true)) 8299 return; 8300 } 8301 } 8302 } 8303 8304 //===--- CHECK: Empty statement body (-Wempty-body) ---------------------===// 8305 8306 namespace { 8307 bool ShouldDiagnoseEmptyStmtBody(const SourceManager &SourceMgr, 8308 SourceLocation StmtLoc, 8309 const NullStmt *Body) { 8310 // Do not warn if the body is a macro that expands to nothing, e.g: 8311 // 8312 // #define CALL(x) 8313 // if (condition) 8314 // CALL(0); 8315 // 8316 if (Body->hasLeadingEmptyMacro()) 8317 return false; 8318 8319 // Get line numbers of statement and body. 8320 bool StmtLineInvalid; 8321 unsigned StmtLine = SourceMgr.getSpellingLineNumber(StmtLoc, 8322 &StmtLineInvalid); 8323 if (StmtLineInvalid) 8324 return false; 8325 8326 bool BodyLineInvalid; 8327 unsigned BodyLine = SourceMgr.getSpellingLineNumber(Body->getSemiLoc(), 8328 &BodyLineInvalid); 8329 if (BodyLineInvalid) 8330 return false; 8331 8332 // Warn if null statement and body are on the same line. 8333 if (StmtLine != BodyLine) 8334 return false; 8335 8336 return true; 8337 } 8338 } // Unnamed namespace 8339 8340 void Sema::DiagnoseEmptyStmtBody(SourceLocation StmtLoc, 8341 const Stmt *Body, 8342 unsigned DiagID) { 8343 // Since this is a syntactic check, don't emit diagnostic for template 8344 // instantiations, this just adds noise. 8345 if (CurrentInstantiationScope) 8346 return; 8347 8348 // The body should be a null statement. 8349 const NullStmt *NBody = dyn_cast<NullStmt>(Body); 8350 if (!NBody) 8351 return; 8352 8353 // Do the usual checks. 8354 if (!ShouldDiagnoseEmptyStmtBody(SourceMgr, StmtLoc, NBody)) 8355 return; 8356 8357 Diag(NBody->getSemiLoc(), DiagID); 8358 Diag(NBody->getSemiLoc(), diag::note_empty_body_on_separate_line); 8359 } 8360 8361 void Sema::DiagnoseEmptyLoopBody(const Stmt *S, 8362 const Stmt *PossibleBody) { 8363 assert(!CurrentInstantiationScope); // Ensured by caller 8364 8365 SourceLocation StmtLoc; 8366 const Stmt *Body; 8367 unsigned DiagID; 8368 if (const ForStmt *FS = dyn_cast<ForStmt>(S)) { 8369 StmtLoc = FS->getRParenLoc(); 8370 Body = FS->getBody(); 8371 DiagID = diag::warn_empty_for_body; 8372 } else if (const WhileStmt *WS = dyn_cast<WhileStmt>(S)) { 8373 StmtLoc = WS->getCond()->getSourceRange().getEnd(); 8374 Body = WS->getBody(); 8375 DiagID = diag::warn_empty_while_body; 8376 } else 8377 return; // Neither `for' nor `while'. 8378 8379 // The body should be a null statement. 8380 const NullStmt *NBody = dyn_cast<NullStmt>(Body); 8381 if (!NBody) 8382 return; 8383 8384 // Skip expensive checks if diagnostic is disabled. 8385 if (Diags.isIgnored(DiagID, NBody->getSemiLoc())) 8386 return; 8387 8388 // Do the usual checks. 8389 if (!ShouldDiagnoseEmptyStmtBody(SourceMgr, StmtLoc, NBody)) 8390 return; 8391 8392 // `for(...);' and `while(...);' are popular idioms, so in order to keep 8393 // noise level low, emit diagnostics only if for/while is followed by a 8394 // CompoundStmt, e.g.: 8395 // for (int i = 0; i < n; i++); 8396 // { 8397 // a(i); 8398 // } 8399 // or if for/while is followed by a statement with more indentation 8400 // than for/while itself: 8401 // for (int i = 0; i < n; i++); 8402 // a(i); 8403 bool ProbableTypo = isa<CompoundStmt>(PossibleBody); 8404 if (!ProbableTypo) { 8405 bool BodyColInvalid; 8406 unsigned BodyCol = SourceMgr.getPresumedColumnNumber( 8407 PossibleBody->getLocStart(), 8408 &BodyColInvalid); 8409 if (BodyColInvalid) 8410 return; 8411 8412 bool StmtColInvalid; 8413 unsigned StmtCol = SourceMgr.getPresumedColumnNumber( 8414 S->getLocStart(), 8415 &StmtColInvalid); 8416 if (StmtColInvalid) 8417 return; 8418 8419 if (BodyCol > StmtCol) 8420 ProbableTypo = true; 8421 } 8422 8423 if (ProbableTypo) { 8424 Diag(NBody->getSemiLoc(), DiagID); 8425 Diag(NBody->getSemiLoc(), diag::note_empty_body_on_separate_line); 8426 } 8427 } 8428 8429 //===--- CHECK: Warn on self move with std::move. -------------------------===// 8430 8431 /// DiagnoseSelfMove - Emits a warning if a value is moved to itself. 8432 void Sema::DiagnoseSelfMove(const Expr *LHSExpr, const Expr *RHSExpr, 8433 SourceLocation OpLoc) { 8434 8435 if (Diags.isIgnored(diag::warn_sizeof_pointer_expr_memaccess, OpLoc)) 8436 return; 8437 8438 if (!ActiveTemplateInstantiations.empty()) 8439 return; 8440 8441 // Strip parens and casts away. 8442 LHSExpr = LHSExpr->IgnoreParenImpCasts(); 8443 RHSExpr = RHSExpr->IgnoreParenImpCasts(); 8444 8445 // Check for a call expression 8446 const CallExpr *CE = dyn_cast<CallExpr>(RHSExpr); 8447 if (!CE || CE->getNumArgs() != 1) 8448 return; 8449 8450 // Check for a call to std::move 8451 const FunctionDecl *FD = CE->getDirectCallee(); 8452 if (!FD || !FD->isInStdNamespace() || !FD->getIdentifier() || 8453 !FD->getIdentifier()->isStr("move")) 8454 return; 8455 8456 // Get argument from std::move 8457 RHSExpr = CE->getArg(0); 8458 8459 const DeclRefExpr *LHSDeclRef = dyn_cast<DeclRefExpr>(LHSExpr); 8460 const DeclRefExpr *RHSDeclRef = dyn_cast<DeclRefExpr>(RHSExpr); 8461 8462 // Two DeclRefExpr's, check that the decls are the same. 8463 if (LHSDeclRef && RHSDeclRef) { 8464 if (!LHSDeclRef->getDecl() || !RHSDeclRef->getDecl()) 8465 return; 8466 if (LHSDeclRef->getDecl()->getCanonicalDecl() != 8467 RHSDeclRef->getDecl()->getCanonicalDecl()) 8468 return; 8469 8470 Diag(OpLoc, diag::warn_self_move) << LHSExpr->getType() 8471 << LHSExpr->getSourceRange() 8472 << RHSExpr->getSourceRange(); 8473 return; 8474 } 8475 8476 // Member variables require a different approach to check for self moves. 8477 // MemberExpr's are the same if every nested MemberExpr refers to the same 8478 // Decl and that the base Expr's are DeclRefExpr's with the same Decl or 8479 // the base Expr's are CXXThisExpr's. 8480 const Expr *LHSBase = LHSExpr; 8481 const Expr *RHSBase = RHSExpr; 8482 const MemberExpr *LHSME = dyn_cast<MemberExpr>(LHSExpr); 8483 const MemberExpr *RHSME = dyn_cast<MemberExpr>(RHSExpr); 8484 if (!LHSME || !RHSME) 8485 return; 8486 8487 while (LHSME && RHSME) { 8488 if (LHSME->getMemberDecl()->getCanonicalDecl() != 8489 RHSME->getMemberDecl()->getCanonicalDecl()) 8490 return; 8491 8492 LHSBase = LHSME->getBase(); 8493 RHSBase = RHSME->getBase(); 8494 LHSME = dyn_cast<MemberExpr>(LHSBase); 8495 RHSME = dyn_cast<MemberExpr>(RHSBase); 8496 } 8497 8498 LHSDeclRef = dyn_cast<DeclRefExpr>(LHSBase); 8499 RHSDeclRef = dyn_cast<DeclRefExpr>(RHSBase); 8500 if (LHSDeclRef && RHSDeclRef) { 8501 if (!LHSDeclRef->getDecl() || !RHSDeclRef->getDecl()) 8502 return; 8503 if (LHSDeclRef->getDecl()->getCanonicalDecl() != 8504 RHSDeclRef->getDecl()->getCanonicalDecl()) 8505 return; 8506 8507 Diag(OpLoc, diag::warn_self_move) << LHSExpr->getType() 8508 << LHSExpr->getSourceRange() 8509 << RHSExpr->getSourceRange(); 8510 return; 8511 } 8512 8513 if (isa<CXXThisExpr>(LHSBase) && isa<CXXThisExpr>(RHSBase)) 8514 Diag(OpLoc, diag::warn_self_move) << LHSExpr->getType() 8515 << LHSExpr->getSourceRange() 8516 << RHSExpr->getSourceRange(); 8517 } 8518 8519 //===--- Layout compatibility ----------------------------------------------// 8520 8521 namespace { 8522 8523 bool isLayoutCompatible(ASTContext &C, QualType T1, QualType T2); 8524 8525 /// \brief Check if two enumeration types are layout-compatible. 8526 bool isLayoutCompatible(ASTContext &C, EnumDecl *ED1, EnumDecl *ED2) { 8527 // C++11 [dcl.enum] p8: 8528 // Two enumeration types are layout-compatible if they have the same 8529 // underlying type. 8530 return ED1->isComplete() && ED2->isComplete() && 8531 C.hasSameType(ED1->getIntegerType(), ED2->getIntegerType()); 8532 } 8533 8534 /// \brief Check if two fields are layout-compatible. 8535 bool isLayoutCompatible(ASTContext &C, FieldDecl *Field1, FieldDecl *Field2) { 8536 if (!isLayoutCompatible(C, Field1->getType(), Field2->getType())) 8537 return false; 8538 8539 if (Field1->isBitField() != Field2->isBitField()) 8540 return false; 8541 8542 if (Field1->isBitField()) { 8543 // Make sure that the bit-fields are the same length. 8544 unsigned Bits1 = Field1->getBitWidthValue(C); 8545 unsigned Bits2 = Field2->getBitWidthValue(C); 8546 8547 if (Bits1 != Bits2) 8548 return false; 8549 } 8550 8551 return true; 8552 } 8553 8554 /// \brief Check if two standard-layout structs are layout-compatible. 8555 /// (C++11 [class.mem] p17) 8556 bool isLayoutCompatibleStruct(ASTContext &C, 8557 RecordDecl *RD1, 8558 RecordDecl *RD2) { 8559 // If both records are C++ classes, check that base classes match. 8560 if (const CXXRecordDecl *D1CXX = dyn_cast<CXXRecordDecl>(RD1)) { 8561 // If one of records is a CXXRecordDecl we are in C++ mode, 8562 // thus the other one is a CXXRecordDecl, too. 8563 const CXXRecordDecl *D2CXX = cast<CXXRecordDecl>(RD2); 8564 // Check number of base classes. 8565 if (D1CXX->getNumBases() != D2CXX->getNumBases()) 8566 return false; 8567 8568 // Check the base classes. 8569 for (CXXRecordDecl::base_class_const_iterator 8570 Base1 = D1CXX->bases_begin(), 8571 BaseEnd1 = D1CXX->bases_end(), 8572 Base2 = D2CXX->bases_begin(); 8573 Base1 != BaseEnd1; 8574 ++Base1, ++Base2) { 8575 if (!isLayoutCompatible(C, Base1->getType(), Base2->getType())) 8576 return false; 8577 } 8578 } else if (const CXXRecordDecl *D2CXX = dyn_cast<CXXRecordDecl>(RD2)) { 8579 // If only RD2 is a C++ class, it should have zero base classes. 8580 if (D2CXX->getNumBases() > 0) 8581 return false; 8582 } 8583 8584 // Check the fields. 8585 RecordDecl::field_iterator Field2 = RD2->field_begin(), 8586 Field2End = RD2->field_end(), 8587 Field1 = RD1->field_begin(), 8588 Field1End = RD1->field_end(); 8589 for ( ; Field1 != Field1End && Field2 != Field2End; ++Field1, ++Field2) { 8590 if (!isLayoutCompatible(C, *Field1, *Field2)) 8591 return false; 8592 } 8593 if (Field1 != Field1End || Field2 != Field2End) 8594 return false; 8595 8596 return true; 8597 } 8598 8599 /// \brief Check if two standard-layout unions are layout-compatible. 8600 /// (C++11 [class.mem] p18) 8601 bool isLayoutCompatibleUnion(ASTContext &C, 8602 RecordDecl *RD1, 8603 RecordDecl *RD2) { 8604 llvm::SmallPtrSet<FieldDecl *, 8> UnmatchedFields; 8605 for (auto *Field2 : RD2->fields()) 8606 UnmatchedFields.insert(Field2); 8607 8608 for (auto *Field1 : RD1->fields()) { 8609 llvm::SmallPtrSet<FieldDecl *, 8>::iterator 8610 I = UnmatchedFields.begin(), 8611 E = UnmatchedFields.end(); 8612 8613 for ( ; I != E; ++I) { 8614 if (isLayoutCompatible(C, Field1, *I)) { 8615 bool Result = UnmatchedFields.erase(*I); 8616 (void) Result; 8617 assert(Result); 8618 break; 8619 } 8620 } 8621 if (I == E) 8622 return false; 8623 } 8624 8625 return UnmatchedFields.empty(); 8626 } 8627 8628 bool isLayoutCompatible(ASTContext &C, RecordDecl *RD1, RecordDecl *RD2) { 8629 if (RD1->isUnion() != RD2->isUnion()) 8630 return false; 8631 8632 if (RD1->isUnion()) 8633 return isLayoutCompatibleUnion(C, RD1, RD2); 8634 else 8635 return isLayoutCompatibleStruct(C, RD1, RD2); 8636 } 8637 8638 /// \brief Check if two types are layout-compatible in C++11 sense. 8639 bool isLayoutCompatible(ASTContext &C, QualType T1, QualType T2) { 8640 if (T1.isNull() || T2.isNull()) 8641 return false; 8642 8643 // C++11 [basic.types] p11: 8644 // If two types T1 and T2 are the same type, then T1 and T2 are 8645 // layout-compatible types. 8646 if (C.hasSameType(T1, T2)) 8647 return true; 8648 8649 T1 = T1.getCanonicalType().getUnqualifiedType(); 8650 T2 = T2.getCanonicalType().getUnqualifiedType(); 8651 8652 const Type::TypeClass TC1 = T1->getTypeClass(); 8653 const Type::TypeClass TC2 = T2->getTypeClass(); 8654 8655 if (TC1 != TC2) 8656 return false; 8657 8658 if (TC1 == Type::Enum) { 8659 return isLayoutCompatible(C, 8660 cast<EnumType>(T1)->getDecl(), 8661 cast<EnumType>(T2)->getDecl()); 8662 } else if (TC1 == Type::Record) { 8663 if (!T1->isStandardLayoutType() || !T2->isStandardLayoutType()) 8664 return false; 8665 8666 return isLayoutCompatible(C, 8667 cast<RecordType>(T1)->getDecl(), 8668 cast<RecordType>(T2)->getDecl()); 8669 } 8670 8671 return false; 8672 } 8673 } 8674 8675 //===--- CHECK: pointer_with_type_tag attribute: datatypes should match ----// 8676 8677 namespace { 8678 /// \brief Given a type tag expression find the type tag itself. 8679 /// 8680 /// \param TypeExpr Type tag expression, as it appears in user's code. 8681 /// 8682 /// \param VD Declaration of an identifier that appears in a type tag. 8683 /// 8684 /// \param MagicValue Type tag magic value. 8685 bool FindTypeTagExpr(const Expr *TypeExpr, const ASTContext &Ctx, 8686 const ValueDecl **VD, uint64_t *MagicValue) { 8687 while(true) { 8688 if (!TypeExpr) 8689 return false; 8690 8691 TypeExpr = TypeExpr->IgnoreParenImpCasts()->IgnoreParenCasts(); 8692 8693 switch (TypeExpr->getStmtClass()) { 8694 case Stmt::UnaryOperatorClass: { 8695 const UnaryOperator *UO = cast<UnaryOperator>(TypeExpr); 8696 if (UO->getOpcode() == UO_AddrOf || UO->getOpcode() == UO_Deref) { 8697 TypeExpr = UO->getSubExpr(); 8698 continue; 8699 } 8700 return false; 8701 } 8702 8703 case Stmt::DeclRefExprClass: { 8704 const DeclRefExpr *DRE = cast<DeclRefExpr>(TypeExpr); 8705 *VD = DRE->getDecl(); 8706 return true; 8707 } 8708 8709 case Stmt::IntegerLiteralClass: { 8710 const IntegerLiteral *IL = cast<IntegerLiteral>(TypeExpr); 8711 llvm::APInt MagicValueAPInt = IL->getValue(); 8712 if (MagicValueAPInt.getActiveBits() <= 64) { 8713 *MagicValue = MagicValueAPInt.getZExtValue(); 8714 return true; 8715 } else 8716 return false; 8717 } 8718 8719 case Stmt::BinaryConditionalOperatorClass: 8720 case Stmt::ConditionalOperatorClass: { 8721 const AbstractConditionalOperator *ACO = 8722 cast<AbstractConditionalOperator>(TypeExpr); 8723 bool Result; 8724 if (ACO->getCond()->EvaluateAsBooleanCondition(Result, Ctx)) { 8725 if (Result) 8726 TypeExpr = ACO->getTrueExpr(); 8727 else 8728 TypeExpr = ACO->getFalseExpr(); 8729 continue; 8730 } 8731 return false; 8732 } 8733 8734 case Stmt::BinaryOperatorClass: { 8735 const BinaryOperator *BO = cast<BinaryOperator>(TypeExpr); 8736 if (BO->getOpcode() == BO_Comma) { 8737 TypeExpr = BO->getRHS(); 8738 continue; 8739 } 8740 return false; 8741 } 8742 8743 default: 8744 return false; 8745 } 8746 } 8747 } 8748 8749 /// \brief Retrieve the C type corresponding to type tag TypeExpr. 8750 /// 8751 /// \param TypeExpr Expression that specifies a type tag. 8752 /// 8753 /// \param MagicValues Registered magic values. 8754 /// 8755 /// \param FoundWrongKind Set to true if a type tag was found, but of a wrong 8756 /// kind. 8757 /// 8758 /// \param TypeInfo Information about the corresponding C type. 8759 /// 8760 /// \returns true if the corresponding C type was found. 8761 bool GetMatchingCType( 8762 const IdentifierInfo *ArgumentKind, 8763 const Expr *TypeExpr, const ASTContext &Ctx, 8764 const llvm::DenseMap<Sema::TypeTagMagicValue, 8765 Sema::TypeTagData> *MagicValues, 8766 bool &FoundWrongKind, 8767 Sema::TypeTagData &TypeInfo) { 8768 FoundWrongKind = false; 8769 8770 // Variable declaration that has type_tag_for_datatype attribute. 8771 const ValueDecl *VD = nullptr; 8772 8773 uint64_t MagicValue; 8774 8775 if (!FindTypeTagExpr(TypeExpr, Ctx, &VD, &MagicValue)) 8776 return false; 8777 8778 if (VD) { 8779 if (TypeTagForDatatypeAttr *I = VD->getAttr<TypeTagForDatatypeAttr>()) { 8780 if (I->getArgumentKind() != ArgumentKind) { 8781 FoundWrongKind = true; 8782 return false; 8783 } 8784 TypeInfo.Type = I->getMatchingCType(); 8785 TypeInfo.LayoutCompatible = I->getLayoutCompatible(); 8786 TypeInfo.MustBeNull = I->getMustBeNull(); 8787 return true; 8788 } 8789 return false; 8790 } 8791 8792 if (!MagicValues) 8793 return false; 8794 8795 llvm::DenseMap<Sema::TypeTagMagicValue, 8796 Sema::TypeTagData>::const_iterator I = 8797 MagicValues->find(std::make_pair(ArgumentKind, MagicValue)); 8798 if (I == MagicValues->end()) 8799 return false; 8800 8801 TypeInfo = I->second; 8802 return true; 8803 } 8804 } // unnamed namespace 8805 8806 void Sema::RegisterTypeTagForDatatype(const IdentifierInfo *ArgumentKind, 8807 uint64_t MagicValue, QualType Type, 8808 bool LayoutCompatible, 8809 bool MustBeNull) { 8810 if (!TypeTagForDatatypeMagicValues) 8811 TypeTagForDatatypeMagicValues.reset( 8812 new llvm::DenseMap<TypeTagMagicValue, TypeTagData>); 8813 8814 TypeTagMagicValue Magic(ArgumentKind, MagicValue); 8815 (*TypeTagForDatatypeMagicValues)[Magic] = 8816 TypeTagData(Type, LayoutCompatible, MustBeNull); 8817 } 8818 8819 namespace { 8820 bool IsSameCharType(QualType T1, QualType T2) { 8821 const BuiltinType *BT1 = T1->getAs<BuiltinType>(); 8822 if (!BT1) 8823 return false; 8824 8825 const BuiltinType *BT2 = T2->getAs<BuiltinType>(); 8826 if (!BT2) 8827 return false; 8828 8829 BuiltinType::Kind T1Kind = BT1->getKind(); 8830 BuiltinType::Kind T2Kind = BT2->getKind(); 8831 8832 return (T1Kind == BuiltinType::SChar && T2Kind == BuiltinType::Char_S) || 8833 (T1Kind == BuiltinType::UChar && T2Kind == BuiltinType::Char_U) || 8834 (T1Kind == BuiltinType::Char_U && T2Kind == BuiltinType::UChar) || 8835 (T1Kind == BuiltinType::Char_S && T2Kind == BuiltinType::SChar); 8836 } 8837 } // unnamed namespace 8838 8839 void Sema::CheckArgumentWithTypeTag(const ArgumentWithTypeTagAttr *Attr, 8840 const Expr * const *ExprArgs) { 8841 const IdentifierInfo *ArgumentKind = Attr->getArgumentKind(); 8842 bool IsPointerAttr = Attr->getIsPointer(); 8843 8844 const Expr *TypeTagExpr = ExprArgs[Attr->getTypeTagIdx()]; 8845 bool FoundWrongKind; 8846 TypeTagData TypeInfo; 8847 if (!GetMatchingCType(ArgumentKind, TypeTagExpr, Context, 8848 TypeTagForDatatypeMagicValues.get(), 8849 FoundWrongKind, TypeInfo)) { 8850 if (FoundWrongKind) 8851 Diag(TypeTagExpr->getExprLoc(), 8852 diag::warn_type_tag_for_datatype_wrong_kind) 8853 << TypeTagExpr->getSourceRange(); 8854 return; 8855 } 8856 8857 const Expr *ArgumentExpr = ExprArgs[Attr->getArgumentIdx()]; 8858 if (IsPointerAttr) { 8859 // Skip implicit cast of pointer to `void *' (as a function argument). 8860 if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(ArgumentExpr)) 8861 if (ICE->getType()->isVoidPointerType() && 8862 ICE->getCastKind() == CK_BitCast) 8863 ArgumentExpr = ICE->getSubExpr(); 8864 } 8865 QualType ArgumentType = ArgumentExpr->getType(); 8866 8867 // Passing a `void*' pointer shouldn't trigger a warning. 8868 if (IsPointerAttr && ArgumentType->isVoidPointerType()) 8869 return; 8870 8871 if (TypeInfo.MustBeNull) { 8872 // Type tag with matching void type requires a null pointer. 8873 if (!ArgumentExpr->isNullPointerConstant(Context, 8874 Expr::NPC_ValueDependentIsNotNull)) { 8875 Diag(ArgumentExpr->getExprLoc(), 8876 diag::warn_type_safety_null_pointer_required) 8877 << ArgumentKind->getName() 8878 << ArgumentExpr->getSourceRange() 8879 << TypeTagExpr->getSourceRange(); 8880 } 8881 return; 8882 } 8883 8884 QualType RequiredType = TypeInfo.Type; 8885 if (IsPointerAttr) 8886 RequiredType = Context.getPointerType(RequiredType); 8887 8888 bool mismatch = false; 8889 if (!TypeInfo.LayoutCompatible) { 8890 mismatch = !Context.hasSameType(ArgumentType, RequiredType); 8891 8892 // C++11 [basic.fundamental] p1: 8893 // Plain char, signed char, and unsigned char are three distinct types. 8894 // 8895 // But we treat plain `char' as equivalent to `signed char' or `unsigned 8896 // char' depending on the current char signedness mode. 8897 if (mismatch) 8898 if ((IsPointerAttr && IsSameCharType(ArgumentType->getPointeeType(), 8899 RequiredType->getPointeeType())) || 8900 (!IsPointerAttr && IsSameCharType(ArgumentType, RequiredType))) 8901 mismatch = false; 8902 } else 8903 if (IsPointerAttr) 8904 mismatch = !isLayoutCompatible(Context, 8905 ArgumentType->getPointeeType(), 8906 RequiredType->getPointeeType()); 8907 else 8908 mismatch = !isLayoutCompatible(Context, ArgumentType, RequiredType); 8909 8910 if (mismatch) 8911 Diag(ArgumentExpr->getExprLoc(), diag::warn_type_safety_type_mismatch) 8912 << ArgumentType << ArgumentKind 8913 << TypeInfo.LayoutCompatible << RequiredType 8914 << ArgumentExpr->getSourceRange() 8915 << TypeTagExpr->getSourceRange(); 8916 } 8917 8918