SemaChecking.cpp revision b61c294a24324ca0a403df770c01e0ba0b88770b
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/Preprocessor.h" 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/BitVector.h" 36#include "llvm/ADT/STLExtras.h" 37#include "llvm/ADT/SmallString.h" 38#include "llvm/Support/ConvertUTF.h" 39#include "llvm/Support/raw_ostream.h" 40#include <limits> 41using namespace clang; 42using namespace sema; 43 44SourceLocation Sema::getLocationOfStringLiteralByte(const StringLiteral *SL, 45 unsigned ByteNo) const { 46 return SL->getLocationOfByte(ByteNo, PP.getSourceManager(), 47 PP.getLangOpts(), PP.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. 52static 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. 72static 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. 100static bool SemaBuiltinAddressof(Sema &S, CallExpr *TheCall) { 101 if (checkArgCount(S, TheCall, 1)) 102 return true; 103 104 ExprResult Arg(S.Owned(TheCall->getArg(0))); 105 QualType ResultType = S.CheckAddressOfOperand(Arg, TheCall->getLocStart()); 106 if (ResultType.isNull()) 107 return true; 108 109 TheCall->setArg(0, Arg.take()); 110 TheCall->setType(ResultType); 111 return false; 112} 113 114ExprResult 115Sema::CheckBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) { 116 ExprResult TheCallResult(Owned(TheCall)); 117 118 // Find out if any arguments are required to be integer constant expressions. 119 unsigned ICEArguments = 0; 120 ASTContext::GetBuiltinTypeError Error; 121 Context.GetBuiltinType(BuiltinID, Error, &ICEArguments); 122 if (Error != ASTContext::GE_None) 123 ICEArguments = 0; // Don't diagnose previously diagnosed errors. 124 125 // If any arguments are required to be ICE's, check and diagnose. 126 for (unsigned ArgNo = 0; ICEArguments != 0; ++ArgNo) { 127 // Skip arguments not required to be ICE's. 128 if ((ICEArguments & (1 << ArgNo)) == 0) continue; 129 130 llvm::APSInt Result; 131 if (SemaBuiltinConstantArg(TheCall, ArgNo, Result)) 132 return true; 133 ICEArguments &= ~(1 << ArgNo); 134 } 135 136 switch (BuiltinID) { 137 case Builtin::BI__builtin___CFStringMakeConstantString: 138 assert(TheCall->getNumArgs() == 1 && 139 "Wrong # arguments to builtin CFStringMakeConstantString"); 140 if (CheckObjCString(TheCall->getArg(0))) 141 return ExprError(); 142 break; 143 case Builtin::BI__builtin_stdarg_start: 144 case Builtin::BI__builtin_va_start: 145 if (SemaBuiltinVAStart(TheCall)) 146 return ExprError(); 147 break; 148 case Builtin::BI__builtin_isgreater: 149 case Builtin::BI__builtin_isgreaterequal: 150 case Builtin::BI__builtin_isless: 151 case Builtin::BI__builtin_islessequal: 152 case Builtin::BI__builtin_islessgreater: 153 case Builtin::BI__builtin_isunordered: 154 if (SemaBuiltinUnorderedCompare(TheCall)) 155 return ExprError(); 156 break; 157 case Builtin::BI__builtin_fpclassify: 158 if (SemaBuiltinFPClassification(TheCall, 6)) 159 return ExprError(); 160 break; 161 case Builtin::BI__builtin_isfinite: 162 case Builtin::BI__builtin_isinf: 163 case Builtin::BI__builtin_isinf_sign: 164 case Builtin::BI__builtin_isnan: 165 case Builtin::BI__builtin_isnormal: 166 if (SemaBuiltinFPClassification(TheCall, 1)) 167 return ExprError(); 168 break; 169 case Builtin::BI__builtin_shufflevector: 170 return SemaBuiltinShuffleVector(TheCall); 171 // TheCall will be freed by the smart pointer here, but that's fine, since 172 // SemaBuiltinShuffleVector guts it, but then doesn't release it. 173 case Builtin::BI__builtin_prefetch: 174 if (SemaBuiltinPrefetch(TheCall)) 175 return ExprError(); 176 break; 177 case Builtin::BI__builtin_object_size: 178 if (SemaBuiltinObjectSize(TheCall)) 179 return ExprError(); 180 break; 181 case Builtin::BI__builtin_longjmp: 182 if (SemaBuiltinLongjmp(TheCall)) 183 return ExprError(); 184 break; 185 186 case Builtin::BI__builtin_classify_type: 187 if (checkArgCount(*this, TheCall, 1)) return true; 188 TheCall->setType(Context.IntTy); 189 break; 190 case Builtin::BI__builtin_constant_p: 191 if (checkArgCount(*this, TheCall, 1)) return true; 192 TheCall->setType(Context.IntTy); 193 break; 194 case Builtin::BI__sync_fetch_and_add: 195 case Builtin::BI__sync_fetch_and_add_1: 196 case Builtin::BI__sync_fetch_and_add_2: 197 case Builtin::BI__sync_fetch_and_add_4: 198 case Builtin::BI__sync_fetch_and_add_8: 199 case Builtin::BI__sync_fetch_and_add_16: 200 case Builtin::BI__sync_fetch_and_sub: 201 case Builtin::BI__sync_fetch_and_sub_1: 202 case Builtin::BI__sync_fetch_and_sub_2: 203 case Builtin::BI__sync_fetch_and_sub_4: 204 case Builtin::BI__sync_fetch_and_sub_8: 205 case Builtin::BI__sync_fetch_and_sub_16: 206 case Builtin::BI__sync_fetch_and_or: 207 case Builtin::BI__sync_fetch_and_or_1: 208 case Builtin::BI__sync_fetch_and_or_2: 209 case Builtin::BI__sync_fetch_and_or_4: 210 case Builtin::BI__sync_fetch_and_or_8: 211 case Builtin::BI__sync_fetch_and_or_16: 212 case Builtin::BI__sync_fetch_and_and: 213 case Builtin::BI__sync_fetch_and_and_1: 214 case Builtin::BI__sync_fetch_and_and_2: 215 case Builtin::BI__sync_fetch_and_and_4: 216 case Builtin::BI__sync_fetch_and_and_8: 217 case Builtin::BI__sync_fetch_and_and_16: 218 case Builtin::BI__sync_fetch_and_xor: 219 case Builtin::BI__sync_fetch_and_xor_1: 220 case Builtin::BI__sync_fetch_and_xor_2: 221 case Builtin::BI__sync_fetch_and_xor_4: 222 case Builtin::BI__sync_fetch_and_xor_8: 223 case Builtin::BI__sync_fetch_and_xor_16: 224 case Builtin::BI__sync_add_and_fetch: 225 case Builtin::BI__sync_add_and_fetch_1: 226 case Builtin::BI__sync_add_and_fetch_2: 227 case Builtin::BI__sync_add_and_fetch_4: 228 case Builtin::BI__sync_add_and_fetch_8: 229 case Builtin::BI__sync_add_and_fetch_16: 230 case Builtin::BI__sync_sub_and_fetch: 231 case Builtin::BI__sync_sub_and_fetch_1: 232 case Builtin::BI__sync_sub_and_fetch_2: 233 case Builtin::BI__sync_sub_and_fetch_4: 234 case Builtin::BI__sync_sub_and_fetch_8: 235 case Builtin::BI__sync_sub_and_fetch_16: 236 case Builtin::BI__sync_and_and_fetch: 237 case Builtin::BI__sync_and_and_fetch_1: 238 case Builtin::BI__sync_and_and_fetch_2: 239 case Builtin::BI__sync_and_and_fetch_4: 240 case Builtin::BI__sync_and_and_fetch_8: 241 case Builtin::BI__sync_and_and_fetch_16: 242 case Builtin::BI__sync_or_and_fetch: 243 case Builtin::BI__sync_or_and_fetch_1: 244 case Builtin::BI__sync_or_and_fetch_2: 245 case Builtin::BI__sync_or_and_fetch_4: 246 case Builtin::BI__sync_or_and_fetch_8: 247 case Builtin::BI__sync_or_and_fetch_16: 248 case Builtin::BI__sync_xor_and_fetch: 249 case Builtin::BI__sync_xor_and_fetch_1: 250 case Builtin::BI__sync_xor_and_fetch_2: 251 case Builtin::BI__sync_xor_and_fetch_4: 252 case Builtin::BI__sync_xor_and_fetch_8: 253 case Builtin::BI__sync_xor_and_fetch_16: 254 case Builtin::BI__sync_val_compare_and_swap: 255 case Builtin::BI__sync_val_compare_and_swap_1: 256 case Builtin::BI__sync_val_compare_and_swap_2: 257 case Builtin::BI__sync_val_compare_and_swap_4: 258 case Builtin::BI__sync_val_compare_and_swap_8: 259 case Builtin::BI__sync_val_compare_and_swap_16: 260 case Builtin::BI__sync_bool_compare_and_swap: 261 case Builtin::BI__sync_bool_compare_and_swap_1: 262 case Builtin::BI__sync_bool_compare_and_swap_2: 263 case Builtin::BI__sync_bool_compare_and_swap_4: 264 case Builtin::BI__sync_bool_compare_and_swap_8: 265 case Builtin::BI__sync_bool_compare_and_swap_16: 266 case Builtin::BI__sync_lock_test_and_set: 267 case Builtin::BI__sync_lock_test_and_set_1: 268 case Builtin::BI__sync_lock_test_and_set_2: 269 case Builtin::BI__sync_lock_test_and_set_4: 270 case Builtin::BI__sync_lock_test_and_set_8: 271 case Builtin::BI__sync_lock_test_and_set_16: 272 case Builtin::BI__sync_lock_release: 273 case Builtin::BI__sync_lock_release_1: 274 case Builtin::BI__sync_lock_release_2: 275 case Builtin::BI__sync_lock_release_4: 276 case Builtin::BI__sync_lock_release_8: 277 case Builtin::BI__sync_lock_release_16: 278 case Builtin::BI__sync_swap: 279 case Builtin::BI__sync_swap_1: 280 case Builtin::BI__sync_swap_2: 281 case Builtin::BI__sync_swap_4: 282 case Builtin::BI__sync_swap_8: 283 case Builtin::BI__sync_swap_16: 284 return SemaBuiltinAtomicOverloaded(TheCallResult); 285#define BUILTIN(ID, TYPE, ATTRS) 286#define ATOMIC_BUILTIN(ID, TYPE, ATTRS) \ 287 case Builtin::BI##ID: \ 288 return SemaAtomicOpsOverloaded(TheCallResult, AtomicExpr::AO##ID); 289#include "clang/Basic/Builtins.def" 290 case Builtin::BI__builtin_annotation: 291 if (SemaBuiltinAnnotation(*this, TheCall)) 292 return ExprError(); 293 break; 294 case Builtin::BI__builtin_addressof: 295 if (SemaBuiltinAddressof(*this, TheCall)) 296 return ExprError(); 297 break; 298 } 299 300 // Since the target specific builtins for each arch overlap, only check those 301 // of the arch we are compiling for. 302 if (BuiltinID >= Builtin::FirstTSBuiltin) { 303 switch (Context.getTargetInfo().getTriple().getArch()) { 304 case llvm::Triple::arm: 305 case llvm::Triple::thumb: 306 if (CheckARMBuiltinFunctionCall(BuiltinID, TheCall)) 307 return ExprError(); 308 break; 309 case llvm::Triple::aarch64: 310 if (CheckAArch64BuiltinFunctionCall(BuiltinID, TheCall)) 311 return ExprError(); 312 break; 313 case llvm::Triple::mips: 314 case llvm::Triple::mipsel: 315 case llvm::Triple::mips64: 316 case llvm::Triple::mips64el: 317 if (CheckMipsBuiltinFunctionCall(BuiltinID, TheCall)) 318 return ExprError(); 319 break; 320 default: 321 break; 322 } 323 } 324 325 return TheCallResult; 326} 327 328// Get the valid immediate range for the specified NEON type code. 329static unsigned RFT(unsigned t, bool shift = false) { 330 NeonTypeFlags Type(t); 331 int IsQuad = Type.isQuad(); 332 switch (Type.getEltType()) { 333 case NeonTypeFlags::Int8: 334 case NeonTypeFlags::Poly8: 335 return shift ? 7 : (8 << IsQuad) - 1; 336 case NeonTypeFlags::Int16: 337 case NeonTypeFlags::Poly16: 338 return shift ? 15 : (4 << IsQuad) - 1; 339 case NeonTypeFlags::Int32: 340 return shift ? 31 : (2 << IsQuad) - 1; 341 case NeonTypeFlags::Int64: 342 return shift ? 63 : (1 << IsQuad) - 1; 343 case NeonTypeFlags::Float16: 344 assert(!shift && "cannot shift float types!"); 345 return (4 << IsQuad) - 1; 346 case NeonTypeFlags::Float32: 347 assert(!shift && "cannot shift float types!"); 348 return (2 << IsQuad) - 1; 349 case NeonTypeFlags::Float64: 350 assert(!shift && "cannot shift float types!"); 351 return (1 << IsQuad) - 1; 352 } 353 llvm_unreachable("Invalid NeonTypeFlag!"); 354} 355 356/// getNeonEltType - Return the QualType corresponding to the elements of 357/// the vector type specified by the NeonTypeFlags. This is used to check 358/// the pointer arguments for Neon load/store intrinsics. 359static QualType getNeonEltType(NeonTypeFlags Flags, ASTContext &Context) { 360 switch (Flags.getEltType()) { 361 case NeonTypeFlags::Int8: 362 return Flags.isUnsigned() ? Context.UnsignedCharTy : Context.SignedCharTy; 363 case NeonTypeFlags::Int16: 364 return Flags.isUnsigned() ? Context.UnsignedShortTy : Context.ShortTy; 365 case NeonTypeFlags::Int32: 366 return Flags.isUnsigned() ? Context.UnsignedIntTy : Context.IntTy; 367 case NeonTypeFlags::Int64: 368 return Flags.isUnsigned() ? Context.UnsignedLongLongTy : Context.LongLongTy; 369 case NeonTypeFlags::Poly8: 370 return Context.SignedCharTy; 371 case NeonTypeFlags::Poly16: 372 return Context.ShortTy; 373 case NeonTypeFlags::Float16: 374 return Context.UnsignedShortTy; 375 case NeonTypeFlags::Float32: 376 return Context.FloatTy; 377 case NeonTypeFlags::Float64: 378 return Context.DoubleTy; 379 } 380 llvm_unreachable("Invalid NeonTypeFlag!"); 381} 382 383bool Sema::CheckAArch64BuiltinFunctionCall(unsigned BuiltinID, 384 CallExpr *TheCall) { 385 386 llvm::APSInt Result; 387 388 uint64_t mask = 0; 389 unsigned TV = 0; 390 int PtrArgNum = -1; 391 bool HasConstPtr = false; 392 switch (BuiltinID) { 393#define GET_NEON_AARCH64_OVERLOAD_CHECK 394#include "clang/Basic/arm_neon.inc" 395#undef GET_NEON_AARCH64_OVERLOAD_CHECK 396 } 397 398 // For NEON intrinsics which are overloaded on vector element type, validate 399 // the immediate which specifies which variant to emit. 400 unsigned ImmArg = TheCall->getNumArgs() - 1; 401 if (mask) { 402 if (SemaBuiltinConstantArg(TheCall, ImmArg, Result)) 403 return true; 404 405 TV = Result.getLimitedValue(64); 406 if ((TV > 63) || (mask & (1ULL << TV)) == 0) 407 return Diag(TheCall->getLocStart(), diag::err_invalid_neon_type_code) 408 << TheCall->getArg(ImmArg)->getSourceRange(); 409 } 410 411 if (PtrArgNum >= 0) { 412 // Check that pointer arguments have the specified type. 413 Expr *Arg = TheCall->getArg(PtrArgNum); 414 if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(Arg)) 415 Arg = ICE->getSubExpr(); 416 ExprResult RHS = DefaultFunctionArrayLvalueConversion(Arg); 417 QualType RHSTy = RHS.get()->getType(); 418 QualType EltTy = getNeonEltType(NeonTypeFlags(TV), Context); 419 if (HasConstPtr) 420 EltTy = EltTy.withConst(); 421 QualType LHSTy = Context.getPointerType(EltTy); 422 AssignConvertType ConvTy; 423 ConvTy = CheckSingleAssignmentConstraints(LHSTy, RHS); 424 if (RHS.isInvalid()) 425 return true; 426 if (DiagnoseAssignmentResult(ConvTy, Arg->getLocStart(), LHSTy, RHSTy, 427 RHS.get(), AA_Assigning)) 428 return true; 429 } 430 431 // For NEON intrinsics which take an immediate value as part of the 432 // instruction, range check them here. 433 unsigned i = 0, l = 0, u = 0; 434 switch (BuiltinID) { 435 default: 436 return false; 437#define GET_NEON_AARCH64_IMMEDIATE_CHECK 438#include "clang/Basic/arm_neon.inc" 439#undef GET_NEON_AARCH64_IMMEDIATE_CHECK 440 } 441 ; 442 443 // We can't check the value of a dependent argument. 444 if (TheCall->getArg(i)->isTypeDependent() || 445 TheCall->getArg(i)->isValueDependent()) 446 return false; 447 448 // Check that the immediate argument is actually a constant. 449 if (SemaBuiltinConstantArg(TheCall, i, Result)) 450 return true; 451 452 // Range check against the upper/lower values for this isntruction. 453 unsigned Val = Result.getZExtValue(); 454 if (Val < l || Val > (u + l)) 455 return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range) 456 << l << u + l << TheCall->getArg(i)->getSourceRange(); 457 458 return false; 459} 460 461bool Sema::CheckARMBuiltinExclusiveCall(unsigned BuiltinID, CallExpr *TheCall) { 462 assert((BuiltinID == ARM::BI__builtin_arm_ldrex || 463 BuiltinID == ARM::BI__builtin_arm_strex) && 464 "unexpected ARM builtin"); 465 bool IsLdrex = BuiltinID == ARM::BI__builtin_arm_ldrex; 466 467 DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts()); 468 469 // Ensure that we have the proper number of arguments. 470 if (checkArgCount(*this, TheCall, IsLdrex ? 1 : 2)) 471 return true; 472 473 // Inspect the pointer argument of the atomic builtin. This should always be 474 // a pointer type, whose element is an integral scalar or pointer type. 475 // Because it is a pointer type, we don't have to worry about any implicit 476 // casts here. 477 Expr *PointerArg = TheCall->getArg(IsLdrex ? 0 : 1); 478 ExprResult PointerArgRes = DefaultFunctionArrayLvalueConversion(PointerArg); 479 if (PointerArgRes.isInvalid()) 480 return true; 481 PointerArg = PointerArgRes.take(); 482 483 const PointerType *pointerType = PointerArg->getType()->getAs<PointerType>(); 484 if (!pointerType) { 485 Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer) 486 << PointerArg->getType() << PointerArg->getSourceRange(); 487 return true; 488 } 489 490 // ldrex takes a "const volatile T*" and strex takes a "volatile T*". Our next 491 // task is to insert the appropriate casts into the AST. First work out just 492 // what the appropriate type is. 493 QualType ValType = pointerType->getPointeeType(); 494 QualType AddrType = ValType.getUnqualifiedType().withVolatile(); 495 if (IsLdrex) 496 AddrType.addConst(); 497 498 // Issue a warning if the cast is dodgy. 499 CastKind CastNeeded = CK_NoOp; 500 if (!AddrType.isAtLeastAsQualifiedAs(ValType)) { 501 CastNeeded = CK_BitCast; 502 Diag(DRE->getLocStart(), diag::ext_typecheck_convert_discards_qualifiers) 503 << PointerArg->getType() 504 << Context.getPointerType(AddrType) 505 << AA_Passing << PointerArg->getSourceRange(); 506 } 507 508 // Finally, do the cast and replace the argument with the corrected version. 509 AddrType = Context.getPointerType(AddrType); 510 PointerArgRes = ImpCastExprToType(PointerArg, AddrType, CastNeeded); 511 if (PointerArgRes.isInvalid()) 512 return true; 513 PointerArg = PointerArgRes.take(); 514 515 TheCall->setArg(IsLdrex ? 0 : 1, PointerArg); 516 517 // In general, we allow ints, floats and pointers to be loaded and stored. 518 if (!ValType->isIntegerType() && !ValType->isAnyPointerType() && 519 !ValType->isBlockPointerType() && !ValType->isFloatingType()) { 520 Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer_intfltptr) 521 << PointerArg->getType() << PointerArg->getSourceRange(); 522 return true; 523 } 524 525 // But ARM doesn't have instructions to deal with 128-bit versions. 526 if (Context.getTypeSize(ValType) > 64) { 527 Diag(DRE->getLocStart(), diag::err_atomic_exclusive_builtin_pointer_size) 528 << PointerArg->getType() << PointerArg->getSourceRange(); 529 return true; 530 } 531 532 switch (ValType.getObjCLifetime()) { 533 case Qualifiers::OCL_None: 534 case Qualifiers::OCL_ExplicitNone: 535 // okay 536 break; 537 538 case Qualifiers::OCL_Weak: 539 case Qualifiers::OCL_Strong: 540 case Qualifiers::OCL_Autoreleasing: 541 Diag(DRE->getLocStart(), diag::err_arc_atomic_ownership) 542 << ValType << PointerArg->getSourceRange(); 543 return true; 544 } 545 546 547 if (IsLdrex) { 548 TheCall->setType(ValType); 549 return false; 550 } 551 552 // Initialize the argument to be stored. 553 ExprResult ValArg = TheCall->getArg(0); 554 InitializedEntity Entity = InitializedEntity::InitializeParameter( 555 Context, ValType, /*consume*/ false); 556 ValArg = PerformCopyInitialization(Entity, SourceLocation(), ValArg); 557 if (ValArg.isInvalid()) 558 return true; 559 560 TheCall->setArg(0, ValArg.get()); 561 return false; 562} 563 564bool Sema::CheckARMBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) { 565 llvm::APSInt Result; 566 567 if (BuiltinID == ARM::BI__builtin_arm_ldrex || 568 BuiltinID == ARM::BI__builtin_arm_strex) { 569 return CheckARMBuiltinExclusiveCall(BuiltinID, TheCall); 570 } 571 572 uint64_t mask = 0; 573 unsigned TV = 0; 574 int PtrArgNum = -1; 575 bool HasConstPtr = false; 576 switch (BuiltinID) { 577#define GET_NEON_OVERLOAD_CHECK 578#include "clang/Basic/arm_neon.inc" 579#undef GET_NEON_OVERLOAD_CHECK 580 } 581 582 // For NEON intrinsics which are overloaded on vector element type, validate 583 // the immediate which specifies which variant to emit. 584 unsigned ImmArg = TheCall->getNumArgs()-1; 585 if (mask) { 586 if (SemaBuiltinConstantArg(TheCall, ImmArg, Result)) 587 return true; 588 589 TV = Result.getLimitedValue(64); 590 if ((TV > 63) || (mask & (1ULL << TV)) == 0) 591 return Diag(TheCall->getLocStart(), diag::err_invalid_neon_type_code) 592 << TheCall->getArg(ImmArg)->getSourceRange(); 593 } 594 595 if (PtrArgNum >= 0) { 596 // Check that pointer arguments have the specified type. 597 Expr *Arg = TheCall->getArg(PtrArgNum); 598 if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(Arg)) 599 Arg = ICE->getSubExpr(); 600 ExprResult RHS = DefaultFunctionArrayLvalueConversion(Arg); 601 QualType RHSTy = RHS.get()->getType(); 602 QualType EltTy = getNeonEltType(NeonTypeFlags(TV), Context); 603 if (HasConstPtr) 604 EltTy = EltTy.withConst(); 605 QualType LHSTy = Context.getPointerType(EltTy); 606 AssignConvertType ConvTy; 607 ConvTy = CheckSingleAssignmentConstraints(LHSTy, RHS); 608 if (RHS.isInvalid()) 609 return true; 610 if (DiagnoseAssignmentResult(ConvTy, Arg->getLocStart(), LHSTy, RHSTy, 611 RHS.get(), AA_Assigning)) 612 return true; 613 } 614 615 // For NEON intrinsics which take an immediate value as part of the 616 // instruction, range check them here. 617 unsigned i = 0, l = 0, u = 0; 618 switch (BuiltinID) { 619 default: return false; 620 case ARM::BI__builtin_arm_ssat: i = 1; l = 1; u = 31; break; 621 case ARM::BI__builtin_arm_usat: i = 1; u = 31; break; 622 case ARM::BI__builtin_arm_vcvtr_f: 623 case ARM::BI__builtin_arm_vcvtr_d: i = 1; u = 1; break; 624#define GET_NEON_IMMEDIATE_CHECK 625#include "clang/Basic/arm_neon.inc" 626#undef GET_NEON_IMMEDIATE_CHECK 627 }; 628 629 // We can't check the value of a dependent argument. 630 if (TheCall->getArg(i)->isTypeDependent() || 631 TheCall->getArg(i)->isValueDependent()) 632 return false; 633 634 // Check that the immediate argument is actually a constant. 635 if (SemaBuiltinConstantArg(TheCall, i, Result)) 636 return true; 637 638 // Range check against the upper/lower values for this isntruction. 639 unsigned Val = Result.getZExtValue(); 640 if (Val < l || Val > (u + l)) 641 return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range) 642 << l << u+l << TheCall->getArg(i)->getSourceRange(); 643 644 // FIXME: VFP Intrinsics should error if VFP not present. 645 return false; 646} 647 648bool Sema::CheckMipsBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) { 649 unsigned i = 0, l = 0, u = 0; 650 switch (BuiltinID) { 651 default: return false; 652 case Mips::BI__builtin_mips_wrdsp: i = 1; l = 0; u = 63; break; 653 case Mips::BI__builtin_mips_rddsp: i = 0; l = 0; u = 63; break; 654 case Mips::BI__builtin_mips_append: i = 2; l = 0; u = 31; break; 655 case Mips::BI__builtin_mips_balign: i = 2; l = 0; u = 3; break; 656 case Mips::BI__builtin_mips_precr_sra_ph_w: i = 2; l = 0; u = 31; break; 657 case Mips::BI__builtin_mips_precr_sra_r_ph_w: i = 2; l = 0; u = 31; break; 658 case Mips::BI__builtin_mips_prepend: i = 2; l = 0; u = 31; break; 659 }; 660 661 // We can't check the value of a dependent argument. 662 if (TheCall->getArg(i)->isTypeDependent() || 663 TheCall->getArg(i)->isValueDependent()) 664 return false; 665 666 // Check that the immediate argument is actually a constant. 667 llvm::APSInt Result; 668 if (SemaBuiltinConstantArg(TheCall, i, Result)) 669 return true; 670 671 // Range check against the upper/lower values for this instruction. 672 unsigned Val = Result.getZExtValue(); 673 if (Val < l || Val > u) 674 return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range) 675 << l << u << TheCall->getArg(i)->getSourceRange(); 676 677 return false; 678} 679 680/// Given a FunctionDecl's FormatAttr, attempts to populate the FomatStringInfo 681/// parameter with the FormatAttr's correct format_idx and firstDataArg. 682/// Returns true when the format fits the function and the FormatStringInfo has 683/// been populated. 684bool Sema::getFormatStringInfo(const FormatAttr *Format, bool IsCXXMember, 685 FormatStringInfo *FSI) { 686 FSI->HasVAListArg = Format->getFirstArg() == 0; 687 FSI->FormatIdx = Format->getFormatIdx() - 1; 688 FSI->FirstDataArg = FSI->HasVAListArg ? 0 : Format->getFirstArg() - 1; 689 690 // The way the format attribute works in GCC, the implicit this argument 691 // of member functions is counted. However, it doesn't appear in our own 692 // lists, so decrement format_idx in that case. 693 if (IsCXXMember) { 694 if(FSI->FormatIdx == 0) 695 return false; 696 --FSI->FormatIdx; 697 if (FSI->FirstDataArg != 0) 698 --FSI->FirstDataArg; 699 } 700 return true; 701} 702 703/// Handles the checks for format strings, non-POD arguments to vararg 704/// functions, and NULL arguments passed to non-NULL parameters. 705void Sema::checkCall(NamedDecl *FDecl, 706 ArrayRef<const Expr *> Args, 707 unsigned NumProtoArgs, 708 bool IsMemberFunction, 709 SourceLocation Loc, 710 SourceRange Range, 711 VariadicCallType CallType) { 712 if (CurContext->isDependentContext()) 713 return; 714 715 // Printf and scanf checking. 716 bool HandledFormatString = false; 717 if (FDecl) 718 for (specific_attr_iterator<FormatAttr> 719 I = FDecl->specific_attr_begin<FormatAttr>(), 720 E = FDecl->specific_attr_end<FormatAttr>(); I != E ; ++I) 721 if (CheckFormatArguments(*I, Args, IsMemberFunction, CallType, Loc, 722 Range)) 723 HandledFormatString = true; 724 725 // Refuse POD arguments that weren't caught by the format string 726 // checks above. 727 if (!HandledFormatString && CallType != VariadicDoesNotApply) 728 for (unsigned ArgIdx = NumProtoArgs; ArgIdx < Args.size(); ++ArgIdx) { 729 // Args[ArgIdx] can be null in malformed code. 730 if (const Expr *Arg = Args[ArgIdx]) 731 variadicArgumentPODCheck(Arg, CallType); 732 } 733 734 if (FDecl) { 735 for (specific_attr_iterator<NonNullAttr> 736 I = FDecl->specific_attr_begin<NonNullAttr>(), 737 E = FDecl->specific_attr_end<NonNullAttr>(); I != E; ++I) 738 CheckNonNullArguments(*I, Args.data(), Loc); 739 740 // Type safety checking. 741 for (specific_attr_iterator<ArgumentWithTypeTagAttr> 742 i = FDecl->specific_attr_begin<ArgumentWithTypeTagAttr>(), 743 e = FDecl->specific_attr_end<ArgumentWithTypeTagAttr>(); 744 i != e; ++i) { 745 CheckArgumentWithTypeTag(*i, Args.data()); 746 } 747 } 748} 749 750/// CheckConstructorCall - Check a constructor call for correctness and safety 751/// properties not enforced by the C type system. 752void Sema::CheckConstructorCall(FunctionDecl *FDecl, 753 ArrayRef<const Expr *> Args, 754 const FunctionProtoType *Proto, 755 SourceLocation Loc) { 756 VariadicCallType CallType = 757 Proto->isVariadic() ? VariadicConstructor : VariadicDoesNotApply; 758 checkCall(FDecl, Args, Proto->getNumArgs(), 759 /*IsMemberFunction=*/true, Loc, SourceRange(), CallType); 760} 761 762/// CheckFunctionCall - Check a direct function call for various correctness 763/// and safety properties not strictly enforced by the C type system. 764bool Sema::CheckFunctionCall(FunctionDecl *FDecl, CallExpr *TheCall, 765 const FunctionProtoType *Proto) { 766 bool IsMemberOperatorCall = isa<CXXOperatorCallExpr>(TheCall) && 767 isa<CXXMethodDecl>(FDecl); 768 bool IsMemberFunction = isa<CXXMemberCallExpr>(TheCall) || 769 IsMemberOperatorCall; 770 VariadicCallType CallType = getVariadicCallType(FDecl, Proto, 771 TheCall->getCallee()); 772 unsigned NumProtoArgs = Proto ? Proto->getNumArgs() : 0; 773 Expr** Args = TheCall->getArgs(); 774 unsigned NumArgs = TheCall->getNumArgs(); 775 if (IsMemberOperatorCall) { 776 // If this is a call to a member operator, hide the first argument 777 // from checkCall. 778 // FIXME: Our choice of AST representation here is less than ideal. 779 ++Args; 780 --NumArgs; 781 } 782 checkCall(FDecl, llvm::makeArrayRef<const Expr *>(Args, NumArgs), 783 NumProtoArgs, 784 IsMemberFunction, TheCall->getRParenLoc(), 785 TheCall->getCallee()->getSourceRange(), CallType); 786 787 IdentifierInfo *FnInfo = FDecl->getIdentifier(); 788 // None of the checks below are needed for functions that don't have 789 // simple names (e.g., C++ conversion functions). 790 if (!FnInfo) 791 return false; 792 793 unsigned CMId = FDecl->getMemoryFunctionKind(); 794 if (CMId == 0) 795 return false; 796 797 // Handle memory setting and copying functions. 798 if (CMId == Builtin::BIstrlcpy || CMId == Builtin::BIstrlcat) 799 CheckStrlcpycatArguments(TheCall, FnInfo); 800 else if (CMId == Builtin::BIstrncat) 801 CheckStrncatArguments(TheCall, FnInfo); 802 else 803 CheckMemaccessArguments(TheCall, CMId, FnInfo); 804 805 return false; 806} 807 808bool Sema::CheckObjCMethodCall(ObjCMethodDecl *Method, SourceLocation lbrac, 809 ArrayRef<const Expr *> Args) { 810 VariadicCallType CallType = 811 Method->isVariadic() ? VariadicMethod : VariadicDoesNotApply; 812 813 checkCall(Method, Args, Method->param_size(), 814 /*IsMemberFunction=*/false, 815 lbrac, Method->getSourceRange(), CallType); 816 817 return false; 818} 819 820bool Sema::CheckPointerCall(NamedDecl *NDecl, CallExpr *TheCall, 821 const FunctionProtoType *Proto) { 822 const VarDecl *V = dyn_cast<VarDecl>(NDecl); 823 if (!V) 824 return false; 825 826 QualType Ty = V->getType(); 827 if (!Ty->isBlockPointerType() && !Ty->isFunctionPointerType()) 828 return false; 829 830 VariadicCallType CallType; 831 if (!Proto || !Proto->isVariadic()) { 832 CallType = VariadicDoesNotApply; 833 } else if (Ty->isBlockPointerType()) { 834 CallType = VariadicBlock; 835 } else { // Ty->isFunctionPointerType() 836 CallType = VariadicFunction; 837 } 838 unsigned NumProtoArgs = Proto ? Proto->getNumArgs() : 0; 839 840 checkCall(NDecl, 841 llvm::makeArrayRef<const Expr *>(TheCall->getArgs(), 842 TheCall->getNumArgs()), 843 NumProtoArgs, /*IsMemberFunction=*/false, 844 TheCall->getRParenLoc(), 845 TheCall->getCallee()->getSourceRange(), CallType); 846 847 return false; 848} 849 850/// Checks function calls when a FunctionDecl or a NamedDecl is not available, 851/// such as function pointers returned from functions. 852bool Sema::CheckOtherCall(CallExpr *TheCall, const FunctionProtoType *Proto) { 853 VariadicCallType CallType = getVariadicCallType(/*FDecl=*/0, Proto, 854 TheCall->getCallee()); 855 unsigned NumProtoArgs = Proto ? Proto->getNumArgs() : 0; 856 857 checkCall(/*FDecl=*/0, 858 llvm::makeArrayRef<const Expr *>(TheCall->getArgs(), 859 TheCall->getNumArgs()), 860 NumProtoArgs, /*IsMemberFunction=*/false, 861 TheCall->getRParenLoc(), 862 TheCall->getCallee()->getSourceRange(), CallType); 863 864 return false; 865} 866 867ExprResult Sema::SemaAtomicOpsOverloaded(ExprResult TheCallResult, 868 AtomicExpr::AtomicOp Op) { 869 CallExpr *TheCall = cast<CallExpr>(TheCallResult.get()); 870 DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts()); 871 872 // All these operations take one of the following forms: 873 enum { 874 // C __c11_atomic_init(A *, C) 875 Init, 876 // C __c11_atomic_load(A *, int) 877 Load, 878 // void __atomic_load(A *, CP, int) 879 Copy, 880 // C __c11_atomic_add(A *, M, int) 881 Arithmetic, 882 // C __atomic_exchange_n(A *, CP, int) 883 Xchg, 884 // void __atomic_exchange(A *, C *, CP, int) 885 GNUXchg, 886 // bool __c11_atomic_compare_exchange_strong(A *, C *, CP, int, int) 887 C11CmpXchg, 888 // bool __atomic_compare_exchange(A *, C *, CP, bool, int, int) 889 GNUCmpXchg 890 } Form = Init; 891 const unsigned NumArgs[] = { 2, 2, 3, 3, 3, 4, 5, 6 }; 892 const unsigned NumVals[] = { 1, 0, 1, 1, 1, 2, 2, 3 }; 893 // where: 894 // C is an appropriate type, 895 // A is volatile _Atomic(C) for __c11 builtins and is C for GNU builtins, 896 // CP is C for __c11 builtins and GNU _n builtins and is C * otherwise, 897 // M is C if C is an integer, and ptrdiff_t if C is a pointer, and 898 // the int parameters are for orderings. 899 900 assert(AtomicExpr::AO__c11_atomic_init == 0 && 901 AtomicExpr::AO__c11_atomic_fetch_xor + 1 == AtomicExpr::AO__atomic_load 902 && "need to update code for modified C11 atomics"); 903 bool IsC11 = Op >= AtomicExpr::AO__c11_atomic_init && 904 Op <= AtomicExpr::AO__c11_atomic_fetch_xor; 905 bool IsN = Op == AtomicExpr::AO__atomic_load_n || 906 Op == AtomicExpr::AO__atomic_store_n || 907 Op == AtomicExpr::AO__atomic_exchange_n || 908 Op == AtomicExpr::AO__atomic_compare_exchange_n; 909 bool IsAddSub = false; 910 911 switch (Op) { 912 case AtomicExpr::AO__c11_atomic_init: 913 Form = Init; 914 break; 915 916 case AtomicExpr::AO__c11_atomic_load: 917 case AtomicExpr::AO__atomic_load_n: 918 Form = Load; 919 break; 920 921 case AtomicExpr::AO__c11_atomic_store: 922 case AtomicExpr::AO__atomic_load: 923 case AtomicExpr::AO__atomic_store: 924 case AtomicExpr::AO__atomic_store_n: 925 Form = Copy; 926 break; 927 928 case AtomicExpr::AO__c11_atomic_fetch_add: 929 case AtomicExpr::AO__c11_atomic_fetch_sub: 930 case AtomicExpr::AO__atomic_fetch_add: 931 case AtomicExpr::AO__atomic_fetch_sub: 932 case AtomicExpr::AO__atomic_add_fetch: 933 case AtomicExpr::AO__atomic_sub_fetch: 934 IsAddSub = true; 935 // Fall through. 936 case AtomicExpr::AO__c11_atomic_fetch_and: 937 case AtomicExpr::AO__c11_atomic_fetch_or: 938 case AtomicExpr::AO__c11_atomic_fetch_xor: 939 case AtomicExpr::AO__atomic_fetch_and: 940 case AtomicExpr::AO__atomic_fetch_or: 941 case AtomicExpr::AO__atomic_fetch_xor: 942 case AtomicExpr::AO__atomic_fetch_nand: 943 case AtomicExpr::AO__atomic_and_fetch: 944 case AtomicExpr::AO__atomic_or_fetch: 945 case AtomicExpr::AO__atomic_xor_fetch: 946 case AtomicExpr::AO__atomic_nand_fetch: 947 Form = Arithmetic; 948 break; 949 950 case AtomicExpr::AO__c11_atomic_exchange: 951 case AtomicExpr::AO__atomic_exchange_n: 952 Form = Xchg; 953 break; 954 955 case AtomicExpr::AO__atomic_exchange: 956 Form = GNUXchg; 957 break; 958 959 case AtomicExpr::AO__c11_atomic_compare_exchange_strong: 960 case AtomicExpr::AO__c11_atomic_compare_exchange_weak: 961 Form = C11CmpXchg; 962 break; 963 964 case AtomicExpr::AO__atomic_compare_exchange: 965 case AtomicExpr::AO__atomic_compare_exchange_n: 966 Form = GNUCmpXchg; 967 break; 968 } 969 970 // Check we have the right number of arguments. 971 if (TheCall->getNumArgs() < NumArgs[Form]) { 972 Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args) 973 << 0 << NumArgs[Form] << TheCall->getNumArgs() 974 << TheCall->getCallee()->getSourceRange(); 975 return ExprError(); 976 } else if (TheCall->getNumArgs() > NumArgs[Form]) { 977 Diag(TheCall->getArg(NumArgs[Form])->getLocStart(), 978 diag::err_typecheck_call_too_many_args) 979 << 0 << NumArgs[Form] << TheCall->getNumArgs() 980 << TheCall->getCallee()->getSourceRange(); 981 return ExprError(); 982 } 983 984 // Inspect the first argument of the atomic operation. 985 Expr *Ptr = TheCall->getArg(0); 986 Ptr = DefaultFunctionArrayLvalueConversion(Ptr).get(); 987 const PointerType *pointerType = Ptr->getType()->getAs<PointerType>(); 988 if (!pointerType) { 989 Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer) 990 << Ptr->getType() << Ptr->getSourceRange(); 991 return ExprError(); 992 } 993 994 // For a __c11 builtin, this should be a pointer to an _Atomic type. 995 QualType AtomTy = pointerType->getPointeeType(); // 'A' 996 QualType ValType = AtomTy; // 'C' 997 if (IsC11) { 998 if (!AtomTy->isAtomicType()) { 999 Diag(DRE->getLocStart(), diag::err_atomic_op_needs_atomic) 1000 << Ptr->getType() << Ptr->getSourceRange(); 1001 return ExprError(); 1002 } 1003 if (AtomTy.isConstQualified()) { 1004 Diag(DRE->getLocStart(), diag::err_atomic_op_needs_non_const_atomic) 1005 << Ptr->getType() << Ptr->getSourceRange(); 1006 return ExprError(); 1007 } 1008 ValType = AtomTy->getAs<AtomicType>()->getValueType(); 1009 } 1010 1011 // For an arithmetic operation, the implied arithmetic must be well-formed. 1012 if (Form == Arithmetic) { 1013 // gcc does not enforce these rules for GNU atomics, but we do so for sanity. 1014 if (IsAddSub && !ValType->isIntegerType() && !ValType->isPointerType()) { 1015 Diag(DRE->getLocStart(), diag::err_atomic_op_needs_atomic_int_or_ptr) 1016 << IsC11 << Ptr->getType() << Ptr->getSourceRange(); 1017 return ExprError(); 1018 } 1019 if (!IsAddSub && !ValType->isIntegerType()) { 1020 Diag(DRE->getLocStart(), diag::err_atomic_op_bitwise_needs_atomic_int) 1021 << IsC11 << Ptr->getType() << Ptr->getSourceRange(); 1022 return ExprError(); 1023 } 1024 } else if (IsN && !ValType->isIntegerType() && !ValType->isPointerType()) { 1025 // For __atomic_*_n operations, the value type must be a scalar integral or 1026 // pointer type which is 1, 2, 4, 8 or 16 bytes in length. 1027 Diag(DRE->getLocStart(), diag::err_atomic_op_needs_atomic_int_or_ptr) 1028 << IsC11 << Ptr->getType() << Ptr->getSourceRange(); 1029 return ExprError(); 1030 } 1031 1032 if (!IsC11 && !AtomTy.isTriviallyCopyableType(Context)) { 1033 // For GNU atomics, require a trivially-copyable type. This is not part of 1034 // the GNU atomics specification, but we enforce it for sanity. 1035 Diag(DRE->getLocStart(), diag::err_atomic_op_needs_trivial_copy) 1036 << Ptr->getType() << Ptr->getSourceRange(); 1037 return ExprError(); 1038 } 1039 1040 // FIXME: For any builtin other than a load, the ValType must not be 1041 // const-qualified. 1042 1043 switch (ValType.getObjCLifetime()) { 1044 case Qualifiers::OCL_None: 1045 case Qualifiers::OCL_ExplicitNone: 1046 // okay 1047 break; 1048 1049 case Qualifiers::OCL_Weak: 1050 case Qualifiers::OCL_Strong: 1051 case Qualifiers::OCL_Autoreleasing: 1052 // FIXME: Can this happen? By this point, ValType should be known 1053 // to be trivially copyable. 1054 Diag(DRE->getLocStart(), diag::err_arc_atomic_ownership) 1055 << ValType << Ptr->getSourceRange(); 1056 return ExprError(); 1057 } 1058 1059 QualType ResultType = ValType; 1060 if (Form == Copy || Form == GNUXchg || Form == Init) 1061 ResultType = Context.VoidTy; 1062 else if (Form == C11CmpXchg || Form == GNUCmpXchg) 1063 ResultType = Context.BoolTy; 1064 1065 // The type of a parameter passed 'by value'. In the GNU atomics, such 1066 // arguments are actually passed as pointers. 1067 QualType ByValType = ValType; // 'CP' 1068 if (!IsC11 && !IsN) 1069 ByValType = Ptr->getType(); 1070 1071 // The first argument --- the pointer --- has a fixed type; we 1072 // deduce the types of the rest of the arguments accordingly. Walk 1073 // the remaining arguments, converting them to the deduced value type. 1074 for (unsigned i = 1; i != NumArgs[Form]; ++i) { 1075 QualType Ty; 1076 if (i < NumVals[Form] + 1) { 1077 switch (i) { 1078 case 1: 1079 // The second argument is the non-atomic operand. For arithmetic, this 1080 // is always passed by value, and for a compare_exchange it is always 1081 // passed by address. For the rest, GNU uses by-address and C11 uses 1082 // by-value. 1083 assert(Form != Load); 1084 if (Form == Init || (Form == Arithmetic && ValType->isIntegerType())) 1085 Ty = ValType; 1086 else if (Form == Copy || Form == Xchg) 1087 Ty = ByValType; 1088 else if (Form == Arithmetic) 1089 Ty = Context.getPointerDiffType(); 1090 else 1091 Ty = Context.getPointerType(ValType.getUnqualifiedType()); 1092 break; 1093 case 2: 1094 // The third argument to compare_exchange / GNU exchange is a 1095 // (pointer to a) desired value. 1096 Ty = ByValType; 1097 break; 1098 case 3: 1099 // The fourth argument to GNU compare_exchange is a 'weak' flag. 1100 Ty = Context.BoolTy; 1101 break; 1102 } 1103 } else { 1104 // The order(s) are always converted to int. 1105 Ty = Context.IntTy; 1106 } 1107 1108 InitializedEntity Entity = 1109 InitializedEntity::InitializeParameter(Context, Ty, false); 1110 ExprResult Arg = TheCall->getArg(i); 1111 Arg = PerformCopyInitialization(Entity, SourceLocation(), Arg); 1112 if (Arg.isInvalid()) 1113 return true; 1114 TheCall->setArg(i, Arg.get()); 1115 } 1116 1117 // Permute the arguments into a 'consistent' order. 1118 SmallVector<Expr*, 5> SubExprs; 1119 SubExprs.push_back(Ptr); 1120 switch (Form) { 1121 case Init: 1122 // Note, AtomicExpr::getVal1() has a special case for this atomic. 1123 SubExprs.push_back(TheCall->getArg(1)); // Val1 1124 break; 1125 case Load: 1126 SubExprs.push_back(TheCall->getArg(1)); // Order 1127 break; 1128 case Copy: 1129 case Arithmetic: 1130 case Xchg: 1131 SubExprs.push_back(TheCall->getArg(2)); // Order 1132 SubExprs.push_back(TheCall->getArg(1)); // Val1 1133 break; 1134 case GNUXchg: 1135 // Note, AtomicExpr::getVal2() has a special case for this atomic. 1136 SubExprs.push_back(TheCall->getArg(3)); // Order 1137 SubExprs.push_back(TheCall->getArg(1)); // Val1 1138 SubExprs.push_back(TheCall->getArg(2)); // Val2 1139 break; 1140 case C11CmpXchg: 1141 SubExprs.push_back(TheCall->getArg(3)); // Order 1142 SubExprs.push_back(TheCall->getArg(1)); // Val1 1143 SubExprs.push_back(TheCall->getArg(4)); // OrderFail 1144 SubExprs.push_back(TheCall->getArg(2)); // Val2 1145 break; 1146 case GNUCmpXchg: 1147 SubExprs.push_back(TheCall->getArg(4)); // Order 1148 SubExprs.push_back(TheCall->getArg(1)); // Val1 1149 SubExprs.push_back(TheCall->getArg(5)); // OrderFail 1150 SubExprs.push_back(TheCall->getArg(2)); // Val2 1151 SubExprs.push_back(TheCall->getArg(3)); // Weak 1152 break; 1153 } 1154 1155 AtomicExpr *AE = new (Context) AtomicExpr(TheCall->getCallee()->getLocStart(), 1156 SubExprs, ResultType, Op, 1157 TheCall->getRParenLoc()); 1158 1159 if ((Op == AtomicExpr::AO__c11_atomic_load || 1160 (Op == AtomicExpr::AO__c11_atomic_store)) && 1161 Context.AtomicUsesUnsupportedLibcall(AE)) 1162 Diag(AE->getLocStart(), diag::err_atomic_load_store_uses_lib) << 1163 ((Op == AtomicExpr::AO__c11_atomic_load) ? 0 : 1); 1164 1165 return Owned(AE); 1166} 1167 1168 1169/// checkBuiltinArgument - Given a call to a builtin function, perform 1170/// normal type-checking on the given argument, updating the call in 1171/// place. This is useful when a builtin function requires custom 1172/// type-checking for some of its arguments but not necessarily all of 1173/// them. 1174/// 1175/// Returns true on error. 1176static bool checkBuiltinArgument(Sema &S, CallExpr *E, unsigned ArgIndex) { 1177 FunctionDecl *Fn = E->getDirectCallee(); 1178 assert(Fn && "builtin call without direct callee!"); 1179 1180 ParmVarDecl *Param = Fn->getParamDecl(ArgIndex); 1181 InitializedEntity Entity = 1182 InitializedEntity::InitializeParameter(S.Context, Param); 1183 1184 ExprResult Arg = E->getArg(0); 1185 Arg = S.PerformCopyInitialization(Entity, SourceLocation(), Arg); 1186 if (Arg.isInvalid()) 1187 return true; 1188 1189 E->setArg(ArgIndex, Arg.take()); 1190 return false; 1191} 1192 1193/// SemaBuiltinAtomicOverloaded - We have a call to a function like 1194/// __sync_fetch_and_add, which is an overloaded function based on the pointer 1195/// type of its first argument. The main ActOnCallExpr routines have already 1196/// promoted the types of arguments because all of these calls are prototyped as 1197/// void(...). 1198/// 1199/// This function goes through and does final semantic checking for these 1200/// builtins, 1201ExprResult 1202Sema::SemaBuiltinAtomicOverloaded(ExprResult TheCallResult) { 1203 CallExpr *TheCall = (CallExpr *)TheCallResult.get(); 1204 DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts()); 1205 FunctionDecl *FDecl = cast<FunctionDecl>(DRE->getDecl()); 1206 1207 // Ensure that we have at least one argument to do type inference from. 1208 if (TheCall->getNumArgs() < 1) { 1209 Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args_at_least) 1210 << 0 << 1 << TheCall->getNumArgs() 1211 << TheCall->getCallee()->getSourceRange(); 1212 return ExprError(); 1213 } 1214 1215 // Inspect the first argument of the atomic builtin. This should always be 1216 // a pointer type, whose element is an integral scalar or pointer type. 1217 // Because it is a pointer type, we don't have to worry about any implicit 1218 // casts here. 1219 // FIXME: We don't allow floating point scalars as input. 1220 Expr *FirstArg = TheCall->getArg(0); 1221 ExprResult FirstArgResult = DefaultFunctionArrayLvalueConversion(FirstArg); 1222 if (FirstArgResult.isInvalid()) 1223 return ExprError(); 1224 FirstArg = FirstArgResult.take(); 1225 TheCall->setArg(0, FirstArg); 1226 1227 const PointerType *pointerType = FirstArg->getType()->getAs<PointerType>(); 1228 if (!pointerType) { 1229 Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer) 1230 << FirstArg->getType() << FirstArg->getSourceRange(); 1231 return ExprError(); 1232 } 1233 1234 QualType ValType = pointerType->getPointeeType(); 1235 if (!ValType->isIntegerType() && !ValType->isAnyPointerType() && 1236 !ValType->isBlockPointerType()) { 1237 Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer_intptr) 1238 << FirstArg->getType() << FirstArg->getSourceRange(); 1239 return ExprError(); 1240 } 1241 1242 switch (ValType.getObjCLifetime()) { 1243 case Qualifiers::OCL_None: 1244 case Qualifiers::OCL_ExplicitNone: 1245 // okay 1246 break; 1247 1248 case Qualifiers::OCL_Weak: 1249 case Qualifiers::OCL_Strong: 1250 case Qualifiers::OCL_Autoreleasing: 1251 Diag(DRE->getLocStart(), diag::err_arc_atomic_ownership) 1252 << ValType << FirstArg->getSourceRange(); 1253 return ExprError(); 1254 } 1255 1256 // Strip any qualifiers off ValType. 1257 ValType = ValType.getUnqualifiedType(); 1258 1259 // The majority of builtins return a value, but a few have special return 1260 // types, so allow them to override appropriately below. 1261 QualType ResultType = ValType; 1262 1263 // We need to figure out which concrete builtin this maps onto. For example, 1264 // __sync_fetch_and_add with a 2 byte object turns into 1265 // __sync_fetch_and_add_2. 1266#define BUILTIN_ROW(x) \ 1267 { Builtin::BI##x##_1, Builtin::BI##x##_2, Builtin::BI##x##_4, \ 1268 Builtin::BI##x##_8, Builtin::BI##x##_16 } 1269 1270 static const unsigned BuiltinIndices[][5] = { 1271 BUILTIN_ROW(__sync_fetch_and_add), 1272 BUILTIN_ROW(__sync_fetch_and_sub), 1273 BUILTIN_ROW(__sync_fetch_and_or), 1274 BUILTIN_ROW(__sync_fetch_and_and), 1275 BUILTIN_ROW(__sync_fetch_and_xor), 1276 1277 BUILTIN_ROW(__sync_add_and_fetch), 1278 BUILTIN_ROW(__sync_sub_and_fetch), 1279 BUILTIN_ROW(__sync_and_and_fetch), 1280 BUILTIN_ROW(__sync_or_and_fetch), 1281 BUILTIN_ROW(__sync_xor_and_fetch), 1282 1283 BUILTIN_ROW(__sync_val_compare_and_swap), 1284 BUILTIN_ROW(__sync_bool_compare_and_swap), 1285 BUILTIN_ROW(__sync_lock_test_and_set), 1286 BUILTIN_ROW(__sync_lock_release), 1287 BUILTIN_ROW(__sync_swap) 1288 }; 1289#undef BUILTIN_ROW 1290 1291 // Determine the index of the size. 1292 unsigned SizeIndex; 1293 switch (Context.getTypeSizeInChars(ValType).getQuantity()) { 1294 case 1: SizeIndex = 0; break; 1295 case 2: SizeIndex = 1; break; 1296 case 4: SizeIndex = 2; break; 1297 case 8: SizeIndex = 3; break; 1298 case 16: SizeIndex = 4; break; 1299 default: 1300 Diag(DRE->getLocStart(), diag::err_atomic_builtin_pointer_size) 1301 << FirstArg->getType() << FirstArg->getSourceRange(); 1302 return ExprError(); 1303 } 1304 1305 // Each of these builtins has one pointer argument, followed by some number of 1306 // values (0, 1 or 2) followed by a potentially empty varags list of stuff 1307 // that we ignore. Find out which row of BuiltinIndices to read from as well 1308 // as the number of fixed args. 1309 unsigned BuiltinID = FDecl->getBuiltinID(); 1310 unsigned BuiltinIndex, NumFixed = 1; 1311 switch (BuiltinID) { 1312 default: llvm_unreachable("Unknown overloaded atomic builtin!"); 1313 case Builtin::BI__sync_fetch_and_add: 1314 case Builtin::BI__sync_fetch_and_add_1: 1315 case Builtin::BI__sync_fetch_and_add_2: 1316 case Builtin::BI__sync_fetch_and_add_4: 1317 case Builtin::BI__sync_fetch_and_add_8: 1318 case Builtin::BI__sync_fetch_and_add_16: 1319 BuiltinIndex = 0; 1320 break; 1321 1322 case Builtin::BI__sync_fetch_and_sub: 1323 case Builtin::BI__sync_fetch_and_sub_1: 1324 case Builtin::BI__sync_fetch_and_sub_2: 1325 case Builtin::BI__sync_fetch_and_sub_4: 1326 case Builtin::BI__sync_fetch_and_sub_8: 1327 case Builtin::BI__sync_fetch_and_sub_16: 1328 BuiltinIndex = 1; 1329 break; 1330 1331 case Builtin::BI__sync_fetch_and_or: 1332 case Builtin::BI__sync_fetch_and_or_1: 1333 case Builtin::BI__sync_fetch_and_or_2: 1334 case Builtin::BI__sync_fetch_and_or_4: 1335 case Builtin::BI__sync_fetch_and_or_8: 1336 case Builtin::BI__sync_fetch_and_or_16: 1337 BuiltinIndex = 2; 1338 break; 1339 1340 case Builtin::BI__sync_fetch_and_and: 1341 case Builtin::BI__sync_fetch_and_and_1: 1342 case Builtin::BI__sync_fetch_and_and_2: 1343 case Builtin::BI__sync_fetch_and_and_4: 1344 case Builtin::BI__sync_fetch_and_and_8: 1345 case Builtin::BI__sync_fetch_and_and_16: 1346 BuiltinIndex = 3; 1347 break; 1348 1349 case Builtin::BI__sync_fetch_and_xor: 1350 case Builtin::BI__sync_fetch_and_xor_1: 1351 case Builtin::BI__sync_fetch_and_xor_2: 1352 case Builtin::BI__sync_fetch_and_xor_4: 1353 case Builtin::BI__sync_fetch_and_xor_8: 1354 case Builtin::BI__sync_fetch_and_xor_16: 1355 BuiltinIndex = 4; 1356 break; 1357 1358 case Builtin::BI__sync_add_and_fetch: 1359 case Builtin::BI__sync_add_and_fetch_1: 1360 case Builtin::BI__sync_add_and_fetch_2: 1361 case Builtin::BI__sync_add_and_fetch_4: 1362 case Builtin::BI__sync_add_and_fetch_8: 1363 case Builtin::BI__sync_add_and_fetch_16: 1364 BuiltinIndex = 5; 1365 break; 1366 1367 case Builtin::BI__sync_sub_and_fetch: 1368 case Builtin::BI__sync_sub_and_fetch_1: 1369 case Builtin::BI__sync_sub_and_fetch_2: 1370 case Builtin::BI__sync_sub_and_fetch_4: 1371 case Builtin::BI__sync_sub_and_fetch_8: 1372 case Builtin::BI__sync_sub_and_fetch_16: 1373 BuiltinIndex = 6; 1374 break; 1375 1376 case Builtin::BI__sync_and_and_fetch: 1377 case Builtin::BI__sync_and_and_fetch_1: 1378 case Builtin::BI__sync_and_and_fetch_2: 1379 case Builtin::BI__sync_and_and_fetch_4: 1380 case Builtin::BI__sync_and_and_fetch_8: 1381 case Builtin::BI__sync_and_and_fetch_16: 1382 BuiltinIndex = 7; 1383 break; 1384 1385 case Builtin::BI__sync_or_and_fetch: 1386 case Builtin::BI__sync_or_and_fetch_1: 1387 case Builtin::BI__sync_or_and_fetch_2: 1388 case Builtin::BI__sync_or_and_fetch_4: 1389 case Builtin::BI__sync_or_and_fetch_8: 1390 case Builtin::BI__sync_or_and_fetch_16: 1391 BuiltinIndex = 8; 1392 break; 1393 1394 case Builtin::BI__sync_xor_and_fetch: 1395 case Builtin::BI__sync_xor_and_fetch_1: 1396 case Builtin::BI__sync_xor_and_fetch_2: 1397 case Builtin::BI__sync_xor_and_fetch_4: 1398 case Builtin::BI__sync_xor_and_fetch_8: 1399 case Builtin::BI__sync_xor_and_fetch_16: 1400 BuiltinIndex = 9; 1401 break; 1402 1403 case Builtin::BI__sync_val_compare_and_swap: 1404 case Builtin::BI__sync_val_compare_and_swap_1: 1405 case Builtin::BI__sync_val_compare_and_swap_2: 1406 case Builtin::BI__sync_val_compare_and_swap_4: 1407 case Builtin::BI__sync_val_compare_and_swap_8: 1408 case Builtin::BI__sync_val_compare_and_swap_16: 1409 BuiltinIndex = 10; 1410 NumFixed = 2; 1411 break; 1412 1413 case Builtin::BI__sync_bool_compare_and_swap: 1414 case Builtin::BI__sync_bool_compare_and_swap_1: 1415 case Builtin::BI__sync_bool_compare_and_swap_2: 1416 case Builtin::BI__sync_bool_compare_and_swap_4: 1417 case Builtin::BI__sync_bool_compare_and_swap_8: 1418 case Builtin::BI__sync_bool_compare_and_swap_16: 1419 BuiltinIndex = 11; 1420 NumFixed = 2; 1421 ResultType = Context.BoolTy; 1422 break; 1423 1424 case Builtin::BI__sync_lock_test_and_set: 1425 case Builtin::BI__sync_lock_test_and_set_1: 1426 case Builtin::BI__sync_lock_test_and_set_2: 1427 case Builtin::BI__sync_lock_test_and_set_4: 1428 case Builtin::BI__sync_lock_test_and_set_8: 1429 case Builtin::BI__sync_lock_test_and_set_16: 1430 BuiltinIndex = 12; 1431 break; 1432 1433 case Builtin::BI__sync_lock_release: 1434 case Builtin::BI__sync_lock_release_1: 1435 case Builtin::BI__sync_lock_release_2: 1436 case Builtin::BI__sync_lock_release_4: 1437 case Builtin::BI__sync_lock_release_8: 1438 case Builtin::BI__sync_lock_release_16: 1439 BuiltinIndex = 13; 1440 NumFixed = 0; 1441 ResultType = Context.VoidTy; 1442 break; 1443 1444 case Builtin::BI__sync_swap: 1445 case Builtin::BI__sync_swap_1: 1446 case Builtin::BI__sync_swap_2: 1447 case Builtin::BI__sync_swap_4: 1448 case Builtin::BI__sync_swap_8: 1449 case Builtin::BI__sync_swap_16: 1450 BuiltinIndex = 14; 1451 break; 1452 } 1453 1454 // Now that we know how many fixed arguments we expect, first check that we 1455 // have at least that many. 1456 if (TheCall->getNumArgs() < 1+NumFixed) { 1457 Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args_at_least) 1458 << 0 << 1+NumFixed << TheCall->getNumArgs() 1459 << TheCall->getCallee()->getSourceRange(); 1460 return ExprError(); 1461 } 1462 1463 // Get the decl for the concrete builtin from this, we can tell what the 1464 // concrete integer type we should convert to is. 1465 unsigned NewBuiltinID = BuiltinIndices[BuiltinIndex][SizeIndex]; 1466 const char *NewBuiltinName = Context.BuiltinInfo.GetName(NewBuiltinID); 1467 FunctionDecl *NewBuiltinDecl; 1468 if (NewBuiltinID == BuiltinID) 1469 NewBuiltinDecl = FDecl; 1470 else { 1471 // Perform builtin lookup to avoid redeclaring it. 1472 DeclarationName DN(&Context.Idents.get(NewBuiltinName)); 1473 LookupResult Res(*this, DN, DRE->getLocStart(), LookupOrdinaryName); 1474 LookupName(Res, TUScope, /*AllowBuiltinCreation=*/true); 1475 assert(Res.getFoundDecl()); 1476 NewBuiltinDecl = dyn_cast<FunctionDecl>(Res.getFoundDecl()); 1477 if (NewBuiltinDecl == 0) 1478 return ExprError(); 1479 } 1480 1481 // The first argument --- the pointer --- has a fixed type; we 1482 // deduce the types of the rest of the arguments accordingly. Walk 1483 // the remaining arguments, converting them to the deduced value type. 1484 for (unsigned i = 0; i != NumFixed; ++i) { 1485 ExprResult Arg = TheCall->getArg(i+1); 1486 1487 // GCC does an implicit conversion to the pointer or integer ValType. This 1488 // can fail in some cases (1i -> int**), check for this error case now. 1489 // Initialize the argument. 1490 InitializedEntity Entity = InitializedEntity::InitializeParameter(Context, 1491 ValType, /*consume*/ false); 1492 Arg = PerformCopyInitialization(Entity, SourceLocation(), Arg); 1493 if (Arg.isInvalid()) 1494 return ExprError(); 1495 1496 // Okay, we have something that *can* be converted to the right type. Check 1497 // to see if there is a potentially weird extension going on here. This can 1498 // happen when you do an atomic operation on something like an char* and 1499 // pass in 42. The 42 gets converted to char. This is even more strange 1500 // for things like 45.123 -> char, etc. 1501 // FIXME: Do this check. 1502 TheCall->setArg(i+1, Arg.take()); 1503 } 1504 1505 ASTContext& Context = this->getASTContext(); 1506 1507 // Create a new DeclRefExpr to refer to the new decl. 1508 DeclRefExpr* NewDRE = DeclRefExpr::Create( 1509 Context, 1510 DRE->getQualifierLoc(), 1511 SourceLocation(), 1512 NewBuiltinDecl, 1513 /*enclosing*/ false, 1514 DRE->getLocation(), 1515 Context.BuiltinFnTy, 1516 DRE->getValueKind()); 1517 1518 // Set the callee in the CallExpr. 1519 // FIXME: This loses syntactic information. 1520 QualType CalleePtrTy = Context.getPointerType(NewBuiltinDecl->getType()); 1521 ExprResult PromotedCall = ImpCastExprToType(NewDRE, CalleePtrTy, 1522 CK_BuiltinFnToFnPtr); 1523 TheCall->setCallee(PromotedCall.take()); 1524 1525 // Change the result type of the call to match the original value type. This 1526 // is arbitrary, but the codegen for these builtins ins design to handle it 1527 // gracefully. 1528 TheCall->setType(ResultType); 1529 1530 return TheCallResult; 1531} 1532 1533/// CheckObjCString - Checks that the argument to the builtin 1534/// CFString constructor is correct 1535/// Note: It might also make sense to do the UTF-16 conversion here (would 1536/// simplify the backend). 1537bool Sema::CheckObjCString(Expr *Arg) { 1538 Arg = Arg->IgnoreParenCasts(); 1539 StringLiteral *Literal = dyn_cast<StringLiteral>(Arg); 1540 1541 if (!Literal || !Literal->isAscii()) { 1542 Diag(Arg->getLocStart(), diag::err_cfstring_literal_not_string_constant) 1543 << Arg->getSourceRange(); 1544 return true; 1545 } 1546 1547 if (Literal->containsNonAsciiOrNull()) { 1548 StringRef String = Literal->getString(); 1549 unsigned NumBytes = String.size(); 1550 SmallVector<UTF16, 128> ToBuf(NumBytes); 1551 const UTF8 *FromPtr = (const UTF8 *)String.data(); 1552 UTF16 *ToPtr = &ToBuf[0]; 1553 1554 ConversionResult Result = ConvertUTF8toUTF16(&FromPtr, FromPtr + NumBytes, 1555 &ToPtr, ToPtr + NumBytes, 1556 strictConversion); 1557 // Check for conversion failure. 1558 if (Result != conversionOK) 1559 Diag(Arg->getLocStart(), 1560 diag::warn_cfstring_truncated) << Arg->getSourceRange(); 1561 } 1562 return false; 1563} 1564 1565/// SemaBuiltinVAStart - Check the arguments to __builtin_va_start for validity. 1566/// Emit an error and return true on failure, return false on success. 1567bool Sema::SemaBuiltinVAStart(CallExpr *TheCall) { 1568 Expr *Fn = TheCall->getCallee(); 1569 if (TheCall->getNumArgs() > 2) { 1570 Diag(TheCall->getArg(2)->getLocStart(), 1571 diag::err_typecheck_call_too_many_args) 1572 << 0 /*function call*/ << 2 << TheCall->getNumArgs() 1573 << Fn->getSourceRange() 1574 << SourceRange(TheCall->getArg(2)->getLocStart(), 1575 (*(TheCall->arg_end()-1))->getLocEnd()); 1576 return true; 1577 } 1578 1579 if (TheCall->getNumArgs() < 2) { 1580 return Diag(TheCall->getLocEnd(), 1581 diag::err_typecheck_call_too_few_args_at_least) 1582 << 0 /*function call*/ << 2 << TheCall->getNumArgs(); 1583 } 1584 1585 // Type-check the first argument normally. 1586 if (checkBuiltinArgument(*this, TheCall, 0)) 1587 return true; 1588 1589 // Determine whether the current function is variadic or not. 1590 BlockScopeInfo *CurBlock = getCurBlock(); 1591 bool isVariadic; 1592 if (CurBlock) 1593 isVariadic = CurBlock->TheDecl->isVariadic(); 1594 else if (FunctionDecl *FD = getCurFunctionDecl()) 1595 isVariadic = FD->isVariadic(); 1596 else 1597 isVariadic = getCurMethodDecl()->isVariadic(); 1598 1599 if (!isVariadic) { 1600 Diag(Fn->getLocStart(), diag::err_va_start_used_in_non_variadic_function); 1601 return true; 1602 } 1603 1604 // Verify that the second argument to the builtin is the last argument of the 1605 // current function or method. 1606 bool SecondArgIsLastNamedArgument = false; 1607 const Expr *Arg = TheCall->getArg(1)->IgnoreParenCasts(); 1608 1609 // These are valid if SecondArgIsLastNamedArgument is false after the next 1610 // block. 1611 QualType Type; 1612 SourceLocation ParamLoc; 1613 1614 if (const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(Arg)) { 1615 if (const ParmVarDecl *PV = dyn_cast<ParmVarDecl>(DR->getDecl())) { 1616 // FIXME: This isn't correct for methods (results in bogus warning). 1617 // Get the last formal in the current function. 1618 const ParmVarDecl *LastArg; 1619 if (CurBlock) 1620 LastArg = *(CurBlock->TheDecl->param_end()-1); 1621 else if (FunctionDecl *FD = getCurFunctionDecl()) 1622 LastArg = *(FD->param_end()-1); 1623 else 1624 LastArg = *(getCurMethodDecl()->param_end()-1); 1625 SecondArgIsLastNamedArgument = PV == LastArg; 1626 1627 Type = PV->getType(); 1628 ParamLoc = PV->getLocation(); 1629 } 1630 } 1631 1632 if (!SecondArgIsLastNamedArgument) 1633 Diag(TheCall->getArg(1)->getLocStart(), 1634 diag::warn_second_parameter_of_va_start_not_last_named_argument); 1635 else if (Type->isReferenceType()) { 1636 Diag(Arg->getLocStart(), 1637 diag::warn_va_start_of_reference_type_is_undefined); 1638 Diag(ParamLoc, diag::note_parameter_type) << Type; 1639 } 1640 1641 return false; 1642} 1643 1644/// SemaBuiltinUnorderedCompare - Handle functions like __builtin_isgreater and 1645/// friends. This is declared to take (...), so we have to check everything. 1646bool Sema::SemaBuiltinUnorderedCompare(CallExpr *TheCall) { 1647 if (TheCall->getNumArgs() < 2) 1648 return Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args) 1649 << 0 << 2 << TheCall->getNumArgs()/*function call*/; 1650 if (TheCall->getNumArgs() > 2) 1651 return Diag(TheCall->getArg(2)->getLocStart(), 1652 diag::err_typecheck_call_too_many_args) 1653 << 0 /*function call*/ << 2 << TheCall->getNumArgs() 1654 << SourceRange(TheCall->getArg(2)->getLocStart(), 1655 (*(TheCall->arg_end()-1))->getLocEnd()); 1656 1657 ExprResult OrigArg0 = TheCall->getArg(0); 1658 ExprResult OrigArg1 = TheCall->getArg(1); 1659 1660 // Do standard promotions between the two arguments, returning their common 1661 // type. 1662 QualType Res = UsualArithmeticConversions(OrigArg0, OrigArg1, false); 1663 if (OrigArg0.isInvalid() || OrigArg1.isInvalid()) 1664 return true; 1665 1666 // Make sure any conversions are pushed back into the call; this is 1667 // type safe since unordered compare builtins are declared as "_Bool 1668 // foo(...)". 1669 TheCall->setArg(0, OrigArg0.get()); 1670 TheCall->setArg(1, OrigArg1.get()); 1671 1672 if (OrigArg0.get()->isTypeDependent() || OrigArg1.get()->isTypeDependent()) 1673 return false; 1674 1675 // If the common type isn't a real floating type, then the arguments were 1676 // invalid for this operation. 1677 if (Res.isNull() || !Res->isRealFloatingType()) 1678 return Diag(OrigArg0.get()->getLocStart(), 1679 diag::err_typecheck_call_invalid_ordered_compare) 1680 << OrigArg0.get()->getType() << OrigArg1.get()->getType() 1681 << SourceRange(OrigArg0.get()->getLocStart(), OrigArg1.get()->getLocEnd()); 1682 1683 return false; 1684} 1685 1686/// SemaBuiltinSemaBuiltinFPClassification - Handle functions like 1687/// __builtin_isnan and friends. This is declared to take (...), so we have 1688/// to check everything. We expect the last argument to be a floating point 1689/// value. 1690bool Sema::SemaBuiltinFPClassification(CallExpr *TheCall, unsigned NumArgs) { 1691 if (TheCall->getNumArgs() < NumArgs) 1692 return Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args) 1693 << 0 << NumArgs << TheCall->getNumArgs()/*function call*/; 1694 if (TheCall->getNumArgs() > NumArgs) 1695 return Diag(TheCall->getArg(NumArgs)->getLocStart(), 1696 diag::err_typecheck_call_too_many_args) 1697 << 0 /*function call*/ << NumArgs << TheCall->getNumArgs() 1698 << SourceRange(TheCall->getArg(NumArgs)->getLocStart(), 1699 (*(TheCall->arg_end()-1))->getLocEnd()); 1700 1701 Expr *OrigArg = TheCall->getArg(NumArgs-1); 1702 1703 if (OrigArg->isTypeDependent()) 1704 return false; 1705 1706 // This operation requires a non-_Complex floating-point number. 1707 if (!OrigArg->getType()->isRealFloatingType()) 1708 return Diag(OrigArg->getLocStart(), 1709 diag::err_typecheck_call_invalid_unary_fp) 1710 << OrigArg->getType() << OrigArg->getSourceRange(); 1711 1712 // If this is an implicit conversion from float -> double, remove it. 1713 if (ImplicitCastExpr *Cast = dyn_cast<ImplicitCastExpr>(OrigArg)) { 1714 Expr *CastArg = Cast->getSubExpr(); 1715 if (CastArg->getType()->isSpecificBuiltinType(BuiltinType::Float)) { 1716 assert(Cast->getType()->isSpecificBuiltinType(BuiltinType::Double) && 1717 "promotion from float to double is the only expected cast here"); 1718 Cast->setSubExpr(0); 1719 TheCall->setArg(NumArgs-1, CastArg); 1720 } 1721 } 1722 1723 return false; 1724} 1725 1726/// SemaBuiltinShuffleVector - Handle __builtin_shufflevector. 1727// This is declared to take (...), so we have to check everything. 1728ExprResult Sema::SemaBuiltinShuffleVector(CallExpr *TheCall) { 1729 if (TheCall->getNumArgs() < 2) 1730 return ExprError(Diag(TheCall->getLocEnd(), 1731 diag::err_typecheck_call_too_few_args_at_least) 1732 << 0 /*function call*/ << 2 << TheCall->getNumArgs() 1733 << TheCall->getSourceRange()); 1734 1735 // Determine which of the following types of shufflevector we're checking: 1736 // 1) unary, vector mask: (lhs, mask) 1737 // 2) binary, vector mask: (lhs, rhs, mask) 1738 // 3) binary, scalar mask: (lhs, rhs, index, ..., index) 1739 QualType resType = TheCall->getArg(0)->getType(); 1740 unsigned numElements = 0; 1741 1742 if (!TheCall->getArg(0)->isTypeDependent() && 1743 !TheCall->getArg(1)->isTypeDependent()) { 1744 QualType LHSType = TheCall->getArg(0)->getType(); 1745 QualType RHSType = TheCall->getArg(1)->getType(); 1746 1747 if (!LHSType->isVectorType() || !RHSType->isVectorType()) 1748 return ExprError(Diag(TheCall->getLocStart(), 1749 diag::err_shufflevector_non_vector) 1750 << SourceRange(TheCall->getArg(0)->getLocStart(), 1751 TheCall->getArg(1)->getLocEnd())); 1752 1753 numElements = LHSType->getAs<VectorType>()->getNumElements(); 1754 unsigned numResElements = TheCall->getNumArgs() - 2; 1755 1756 // Check to see if we have a call with 2 vector arguments, the unary shuffle 1757 // with mask. If so, verify that RHS is an integer vector type with the 1758 // same number of elts as lhs. 1759 if (TheCall->getNumArgs() == 2) { 1760 if (!RHSType->hasIntegerRepresentation() || 1761 RHSType->getAs<VectorType>()->getNumElements() != numElements) 1762 return ExprError(Diag(TheCall->getLocStart(), 1763 diag::err_shufflevector_incompatible_vector) 1764 << SourceRange(TheCall->getArg(1)->getLocStart(), 1765 TheCall->getArg(1)->getLocEnd())); 1766 } else if (!Context.hasSameUnqualifiedType(LHSType, RHSType)) { 1767 return ExprError(Diag(TheCall->getLocStart(), 1768 diag::err_shufflevector_incompatible_vector) 1769 << SourceRange(TheCall->getArg(0)->getLocStart(), 1770 TheCall->getArg(1)->getLocEnd())); 1771 } else if (numElements != numResElements) { 1772 QualType eltType = LHSType->getAs<VectorType>()->getElementType(); 1773 resType = Context.getVectorType(eltType, numResElements, 1774 VectorType::GenericVector); 1775 } 1776 } 1777 1778 for (unsigned i = 2; i < TheCall->getNumArgs(); i++) { 1779 if (TheCall->getArg(i)->isTypeDependent() || 1780 TheCall->getArg(i)->isValueDependent()) 1781 continue; 1782 1783 llvm::APSInt Result(32); 1784 if (!TheCall->getArg(i)->isIntegerConstantExpr(Result, Context)) 1785 return ExprError(Diag(TheCall->getLocStart(), 1786 diag::err_shufflevector_nonconstant_argument) 1787 << TheCall->getArg(i)->getSourceRange()); 1788 1789 if (Result.getActiveBits() > 64 || Result.getZExtValue() >= numElements*2) 1790 return ExprError(Diag(TheCall->getLocStart(), 1791 diag::err_shufflevector_argument_too_large) 1792 << TheCall->getArg(i)->getSourceRange()); 1793 } 1794 1795 SmallVector<Expr*, 32> exprs; 1796 1797 for (unsigned i = 0, e = TheCall->getNumArgs(); i != e; i++) { 1798 exprs.push_back(TheCall->getArg(i)); 1799 TheCall->setArg(i, 0); 1800 } 1801 1802 return Owned(new (Context) ShuffleVectorExpr(Context, exprs, resType, 1803 TheCall->getCallee()->getLocStart(), 1804 TheCall->getRParenLoc())); 1805} 1806 1807/// SemaBuiltinPrefetch - Handle __builtin_prefetch. 1808// This is declared to take (const void*, ...) and can take two 1809// optional constant int args. 1810bool Sema::SemaBuiltinPrefetch(CallExpr *TheCall) { 1811 unsigned NumArgs = TheCall->getNumArgs(); 1812 1813 if (NumArgs > 3) 1814 return Diag(TheCall->getLocEnd(), 1815 diag::err_typecheck_call_too_many_args_at_most) 1816 << 0 /*function call*/ << 3 << NumArgs 1817 << TheCall->getSourceRange(); 1818 1819 // Argument 0 is checked for us and the remaining arguments must be 1820 // constant integers. 1821 for (unsigned i = 1; i != NumArgs; ++i) { 1822 Expr *Arg = TheCall->getArg(i); 1823 1824 // We can't check the value of a dependent argument. 1825 if (Arg->isTypeDependent() || Arg->isValueDependent()) 1826 continue; 1827 1828 llvm::APSInt Result; 1829 if (SemaBuiltinConstantArg(TheCall, i, Result)) 1830 return true; 1831 1832 // FIXME: gcc issues a warning and rewrites these to 0. These 1833 // seems especially odd for the third argument since the default 1834 // is 3. 1835 if (i == 1) { 1836 if (Result.getLimitedValue() > 1) 1837 return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range) 1838 << "0" << "1" << Arg->getSourceRange(); 1839 } else { 1840 if (Result.getLimitedValue() > 3) 1841 return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range) 1842 << "0" << "3" << Arg->getSourceRange(); 1843 } 1844 } 1845 1846 return false; 1847} 1848 1849/// SemaBuiltinConstantArg - Handle a check if argument ArgNum of CallExpr 1850/// TheCall is a constant expression. 1851bool Sema::SemaBuiltinConstantArg(CallExpr *TheCall, int ArgNum, 1852 llvm::APSInt &Result) { 1853 Expr *Arg = TheCall->getArg(ArgNum); 1854 DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts()); 1855 FunctionDecl *FDecl = cast<FunctionDecl>(DRE->getDecl()); 1856 1857 if (Arg->isTypeDependent() || Arg->isValueDependent()) return false; 1858 1859 if (!Arg->isIntegerConstantExpr(Result, Context)) 1860 return Diag(TheCall->getLocStart(), diag::err_constant_integer_arg_type) 1861 << FDecl->getDeclName() << Arg->getSourceRange(); 1862 1863 return false; 1864} 1865 1866/// SemaBuiltinObjectSize - Handle __builtin_object_size(void *ptr, 1867/// int type). This simply type checks that type is one of the defined 1868/// constants (0-3). 1869// For compatibility check 0-3, llvm only handles 0 and 2. 1870bool Sema::SemaBuiltinObjectSize(CallExpr *TheCall) { 1871 llvm::APSInt Result; 1872 1873 // We can't check the value of a dependent argument. 1874 if (TheCall->getArg(1)->isTypeDependent() || 1875 TheCall->getArg(1)->isValueDependent()) 1876 return false; 1877 1878 // Check constant-ness first. 1879 if (SemaBuiltinConstantArg(TheCall, 1, Result)) 1880 return true; 1881 1882 Expr *Arg = TheCall->getArg(1); 1883 if (Result.getSExtValue() < 0 || Result.getSExtValue() > 3) { 1884 return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range) 1885 << "0" << "3" << SourceRange(Arg->getLocStart(), Arg->getLocEnd()); 1886 } 1887 1888 return false; 1889} 1890 1891/// SemaBuiltinLongjmp - Handle __builtin_longjmp(void *env[5], int val). 1892/// This checks that val is a constant 1. 1893bool Sema::SemaBuiltinLongjmp(CallExpr *TheCall) { 1894 Expr *Arg = TheCall->getArg(1); 1895 llvm::APSInt Result; 1896 1897 // TODO: This is less than ideal. Overload this to take a value. 1898 if (SemaBuiltinConstantArg(TheCall, 1, Result)) 1899 return true; 1900 1901 if (Result != 1) 1902 return Diag(TheCall->getLocStart(), diag::err_builtin_longjmp_invalid_val) 1903 << SourceRange(Arg->getLocStart(), Arg->getLocEnd()); 1904 1905 return false; 1906} 1907 1908// Determine if an expression is a string literal or constant string. 1909// If this function returns false on the arguments to a function expecting a 1910// format string, we will usually need to emit a warning. 1911// True string literals are then checked by CheckFormatString. 1912Sema::StringLiteralCheckType 1913Sema::checkFormatStringExpr(const Expr *E, ArrayRef<const Expr *> Args, 1914 bool HasVAListArg, 1915 unsigned format_idx, unsigned firstDataArg, 1916 FormatStringType Type, VariadicCallType CallType, 1917 bool inFunctionCall) { 1918 tryAgain: 1919 if (E->isTypeDependent() || E->isValueDependent()) 1920 return SLCT_NotALiteral; 1921 1922 E = E->IgnoreParenCasts(); 1923 1924 if (E->isNullPointerConstant(Context, Expr::NPC_ValueDependentIsNotNull)) 1925 // Technically -Wformat-nonliteral does not warn about this case. 1926 // The behavior of printf and friends in this case is implementation 1927 // dependent. Ideally if the format string cannot be null then 1928 // it should have a 'nonnull' attribute in the function prototype. 1929 return SLCT_CheckedLiteral; 1930 1931 switch (E->getStmtClass()) { 1932 case Stmt::BinaryConditionalOperatorClass: 1933 case Stmt::ConditionalOperatorClass: { 1934 // The expression is a literal if both sub-expressions were, and it was 1935 // completely checked only if both sub-expressions were checked. 1936 const AbstractConditionalOperator *C = 1937 cast<AbstractConditionalOperator>(E); 1938 StringLiteralCheckType Left = 1939 checkFormatStringExpr(C->getTrueExpr(), Args, 1940 HasVAListArg, format_idx, firstDataArg, 1941 Type, CallType, inFunctionCall); 1942 if (Left == SLCT_NotALiteral) 1943 return SLCT_NotALiteral; 1944 StringLiteralCheckType Right = 1945 checkFormatStringExpr(C->getFalseExpr(), Args, 1946 HasVAListArg, format_idx, firstDataArg, 1947 Type, CallType, inFunctionCall); 1948 return Left < Right ? Left : Right; 1949 } 1950 1951 case Stmt::ImplicitCastExprClass: { 1952 E = cast<ImplicitCastExpr>(E)->getSubExpr(); 1953 goto tryAgain; 1954 } 1955 1956 case Stmt::OpaqueValueExprClass: 1957 if (const Expr *src = cast<OpaqueValueExpr>(E)->getSourceExpr()) { 1958 E = src; 1959 goto tryAgain; 1960 } 1961 return SLCT_NotALiteral; 1962 1963 case Stmt::PredefinedExprClass: 1964 // While __func__, etc., are technically not string literals, they 1965 // cannot contain format specifiers and thus are not a security 1966 // liability. 1967 return SLCT_UncheckedLiteral; 1968 1969 case Stmt::DeclRefExprClass: { 1970 const DeclRefExpr *DR = cast<DeclRefExpr>(E); 1971 1972 // As an exception, do not flag errors for variables binding to 1973 // const string literals. 1974 if (const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl())) { 1975 bool isConstant = false; 1976 QualType T = DR->getType(); 1977 1978 if (const ArrayType *AT = Context.getAsArrayType(T)) { 1979 isConstant = AT->getElementType().isConstant(Context); 1980 } else if (const PointerType *PT = T->getAs<PointerType>()) { 1981 isConstant = T.isConstant(Context) && 1982 PT->getPointeeType().isConstant(Context); 1983 } else if (T->isObjCObjectPointerType()) { 1984 // In ObjC, there is usually no "const ObjectPointer" type, 1985 // so don't check if the pointee type is constant. 1986 isConstant = T.isConstant(Context); 1987 } 1988 1989 if (isConstant) { 1990 if (const Expr *Init = VD->getAnyInitializer()) { 1991 // Look through initializers like const char c[] = { "foo" } 1992 if (const InitListExpr *InitList = dyn_cast<InitListExpr>(Init)) { 1993 if (InitList->isStringLiteralInit()) 1994 Init = InitList->getInit(0)->IgnoreParenImpCasts(); 1995 } 1996 return checkFormatStringExpr(Init, Args, 1997 HasVAListArg, format_idx, 1998 firstDataArg, Type, CallType, 1999 /*inFunctionCall*/false); 2000 } 2001 } 2002 2003 // For vprintf* functions (i.e., HasVAListArg==true), we add a 2004 // special check to see if the format string is a function parameter 2005 // of the function calling the printf function. If the function 2006 // has an attribute indicating it is a printf-like function, then we 2007 // should suppress warnings concerning non-literals being used in a call 2008 // to a vprintf function. For example: 2009 // 2010 // void 2011 // logmessage(char const *fmt __attribute__ (format (printf, 1, 2)), ...){ 2012 // va_list ap; 2013 // va_start(ap, fmt); 2014 // vprintf(fmt, ap); // Do NOT emit a warning about "fmt". 2015 // ... 2016 // 2017 if (HasVAListArg) { 2018 if (const ParmVarDecl *PV = dyn_cast<ParmVarDecl>(VD)) { 2019 if (const NamedDecl *ND = dyn_cast<NamedDecl>(PV->getDeclContext())) { 2020 int PVIndex = PV->getFunctionScopeIndex() + 1; 2021 for (specific_attr_iterator<FormatAttr> 2022 i = ND->specific_attr_begin<FormatAttr>(), 2023 e = ND->specific_attr_end<FormatAttr>(); i != e ; ++i) { 2024 FormatAttr *PVFormat = *i; 2025 // adjust for implicit parameter 2026 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(ND)) 2027 if (MD->isInstance()) 2028 ++PVIndex; 2029 // We also check if the formats are compatible. 2030 // We can't pass a 'scanf' string to a 'printf' function. 2031 if (PVIndex == PVFormat->getFormatIdx() && 2032 Type == GetFormatStringType(PVFormat)) 2033 return SLCT_UncheckedLiteral; 2034 } 2035 } 2036 } 2037 } 2038 } 2039 2040 return SLCT_NotALiteral; 2041 } 2042 2043 case Stmt::CallExprClass: 2044 case Stmt::CXXMemberCallExprClass: { 2045 const CallExpr *CE = cast<CallExpr>(E); 2046 if (const NamedDecl *ND = dyn_cast_or_null<NamedDecl>(CE->getCalleeDecl())) { 2047 if (const FormatArgAttr *FA = ND->getAttr<FormatArgAttr>()) { 2048 unsigned ArgIndex = FA->getFormatIdx(); 2049 if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(ND)) 2050 if (MD->isInstance()) 2051 --ArgIndex; 2052 const Expr *Arg = CE->getArg(ArgIndex - 1); 2053 2054 return checkFormatStringExpr(Arg, Args, 2055 HasVAListArg, format_idx, firstDataArg, 2056 Type, CallType, inFunctionCall); 2057 } else if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND)) { 2058 unsigned BuiltinID = FD->getBuiltinID(); 2059 if (BuiltinID == Builtin::BI__builtin___CFStringMakeConstantString || 2060 BuiltinID == Builtin::BI__builtin___NSStringMakeConstantString) { 2061 const Expr *Arg = CE->getArg(0); 2062 return checkFormatStringExpr(Arg, Args, 2063 HasVAListArg, format_idx, 2064 firstDataArg, Type, CallType, 2065 inFunctionCall); 2066 } 2067 } 2068 } 2069 2070 return SLCT_NotALiteral; 2071 } 2072 case Stmt::ObjCStringLiteralClass: 2073 case Stmt::StringLiteralClass: { 2074 const StringLiteral *StrE = NULL; 2075 2076 if (const ObjCStringLiteral *ObjCFExpr = dyn_cast<ObjCStringLiteral>(E)) 2077 StrE = ObjCFExpr->getString(); 2078 else 2079 StrE = cast<StringLiteral>(E); 2080 2081 if (StrE) { 2082 CheckFormatString(StrE, E, Args, HasVAListArg, format_idx, 2083 firstDataArg, Type, inFunctionCall, CallType); 2084 return SLCT_CheckedLiteral; 2085 } 2086 2087 return SLCT_NotALiteral; 2088 } 2089 2090 default: 2091 return SLCT_NotALiteral; 2092 } 2093} 2094 2095void 2096Sema::CheckNonNullArguments(const NonNullAttr *NonNull, 2097 const Expr * const *ExprArgs, 2098 SourceLocation CallSiteLoc) { 2099 for (NonNullAttr::args_iterator i = NonNull->args_begin(), 2100 e = NonNull->args_end(); 2101 i != e; ++i) { 2102 const Expr *ArgExpr = ExprArgs[*i]; 2103 2104 // As a special case, transparent unions initialized with zero are 2105 // considered null for the purposes of the nonnull attribute. 2106 if (const RecordType *UT = ArgExpr->getType()->getAsUnionType()) { 2107 if (UT->getDecl()->hasAttr<TransparentUnionAttr>()) 2108 if (const CompoundLiteralExpr *CLE = 2109 dyn_cast<CompoundLiteralExpr>(ArgExpr)) 2110 if (const InitListExpr *ILE = 2111 dyn_cast<InitListExpr>(CLE->getInitializer())) 2112 ArgExpr = ILE->getInit(0); 2113 } 2114 2115 bool Result; 2116 if (ArgExpr->EvaluateAsBooleanCondition(Result, Context) && !Result) 2117 Diag(CallSiteLoc, diag::warn_null_arg) << ArgExpr->getSourceRange(); 2118 } 2119} 2120 2121Sema::FormatStringType Sema::GetFormatStringType(const FormatAttr *Format) { 2122 return llvm::StringSwitch<FormatStringType>(Format->getType()) 2123 .Case("scanf", FST_Scanf) 2124 .Cases("printf", "printf0", FST_Printf) 2125 .Cases("NSString", "CFString", FST_NSString) 2126 .Case("strftime", FST_Strftime) 2127 .Case("strfmon", FST_Strfmon) 2128 .Cases("kprintf", "cmn_err", "vcmn_err", "zcmn_err", FST_Kprintf) 2129 .Default(FST_Unknown); 2130} 2131 2132/// CheckFormatArguments - Check calls to printf and scanf (and similar 2133/// functions) for correct use of format strings. 2134/// Returns true if a format string has been fully checked. 2135bool Sema::CheckFormatArguments(const FormatAttr *Format, 2136 ArrayRef<const Expr *> Args, 2137 bool IsCXXMember, 2138 VariadicCallType CallType, 2139 SourceLocation Loc, SourceRange Range) { 2140 FormatStringInfo FSI; 2141 if (getFormatStringInfo(Format, IsCXXMember, &FSI)) 2142 return CheckFormatArguments(Args, FSI.HasVAListArg, FSI.FormatIdx, 2143 FSI.FirstDataArg, GetFormatStringType(Format), 2144 CallType, Loc, Range); 2145 return false; 2146} 2147 2148bool Sema::CheckFormatArguments(ArrayRef<const Expr *> Args, 2149 bool HasVAListArg, unsigned format_idx, 2150 unsigned firstDataArg, FormatStringType Type, 2151 VariadicCallType CallType, 2152 SourceLocation Loc, SourceRange Range) { 2153 // CHECK: printf/scanf-like function is called with no format string. 2154 if (format_idx >= Args.size()) { 2155 Diag(Loc, diag::warn_missing_format_string) << Range; 2156 return false; 2157 } 2158 2159 const Expr *OrigFormatExpr = Args[format_idx]->IgnoreParenCasts(); 2160 2161 // CHECK: format string is not a string literal. 2162 // 2163 // Dynamically generated format strings are difficult to 2164 // automatically vet at compile time. Requiring that format strings 2165 // are string literals: (1) permits the checking of format strings by 2166 // the compiler and thereby (2) can practically remove the source of 2167 // many format string exploits. 2168 2169 // Format string can be either ObjC string (e.g. @"%d") or 2170 // C string (e.g. "%d") 2171 // ObjC string uses the same format specifiers as C string, so we can use 2172 // the same format string checking logic for both ObjC and C strings. 2173 StringLiteralCheckType CT = 2174 checkFormatStringExpr(OrigFormatExpr, Args, HasVAListArg, 2175 format_idx, firstDataArg, Type, CallType); 2176 if (CT != SLCT_NotALiteral) 2177 // Literal format string found, check done! 2178 return CT == SLCT_CheckedLiteral; 2179 2180 // Strftime is particular as it always uses a single 'time' argument, 2181 // so it is safe to pass a non-literal string. 2182 if (Type == FST_Strftime) 2183 return false; 2184 2185 // Do not emit diag when the string param is a macro expansion and the 2186 // format is either NSString or CFString. This is a hack to prevent 2187 // diag when using the NSLocalizedString and CFCopyLocalizedString macros 2188 // which are usually used in place of NS and CF string literals. 2189 if (Type == FST_NSString && 2190 SourceMgr.isInSystemMacro(Args[format_idx]->getLocStart())) 2191 return false; 2192 2193 // If there are no arguments specified, warn with -Wformat-security, otherwise 2194 // warn only with -Wformat-nonliteral. 2195 if (Args.size() == firstDataArg) 2196 Diag(Args[format_idx]->getLocStart(), 2197 diag::warn_format_nonliteral_noargs) 2198 << OrigFormatExpr->getSourceRange(); 2199 else 2200 Diag(Args[format_idx]->getLocStart(), 2201 diag::warn_format_nonliteral) 2202 << OrigFormatExpr->getSourceRange(); 2203 return false; 2204} 2205 2206namespace { 2207class CheckFormatHandler : public analyze_format_string::FormatStringHandler { 2208protected: 2209 Sema &S; 2210 const StringLiteral *FExpr; 2211 const Expr *OrigFormatExpr; 2212 const unsigned FirstDataArg; 2213 const unsigned NumDataArgs; 2214 const char *Beg; // Start of format string. 2215 const bool HasVAListArg; 2216 ArrayRef<const Expr *> Args; 2217 unsigned FormatIdx; 2218 llvm::BitVector CoveredArgs; 2219 bool usesPositionalArgs; 2220 bool atFirstArg; 2221 bool inFunctionCall; 2222 Sema::VariadicCallType CallType; 2223public: 2224 CheckFormatHandler(Sema &s, const StringLiteral *fexpr, 2225 const Expr *origFormatExpr, unsigned firstDataArg, 2226 unsigned numDataArgs, const char *beg, bool hasVAListArg, 2227 ArrayRef<const Expr *> Args, 2228 unsigned formatIdx, bool inFunctionCall, 2229 Sema::VariadicCallType callType) 2230 : S(s), FExpr(fexpr), OrigFormatExpr(origFormatExpr), 2231 FirstDataArg(firstDataArg), NumDataArgs(numDataArgs), 2232 Beg(beg), HasVAListArg(hasVAListArg), 2233 Args(Args), FormatIdx(formatIdx), 2234 usesPositionalArgs(false), atFirstArg(true), 2235 inFunctionCall(inFunctionCall), CallType(callType) { 2236 CoveredArgs.resize(numDataArgs); 2237 CoveredArgs.reset(); 2238 } 2239 2240 void DoneProcessing(); 2241 2242 void HandleIncompleteSpecifier(const char *startSpecifier, 2243 unsigned specifierLen); 2244 2245 void HandleInvalidLengthModifier( 2246 const analyze_format_string::FormatSpecifier &FS, 2247 const analyze_format_string::ConversionSpecifier &CS, 2248 const char *startSpecifier, unsigned specifierLen, unsigned DiagID); 2249 2250 void HandleNonStandardLengthModifier( 2251 const analyze_format_string::FormatSpecifier &FS, 2252 const char *startSpecifier, unsigned specifierLen); 2253 2254 void HandleNonStandardConversionSpecifier( 2255 const analyze_format_string::ConversionSpecifier &CS, 2256 const char *startSpecifier, unsigned specifierLen); 2257 2258 virtual void HandlePosition(const char *startPos, unsigned posLen); 2259 2260 virtual void HandleInvalidPosition(const char *startSpecifier, 2261 unsigned specifierLen, 2262 analyze_format_string::PositionContext p); 2263 2264 virtual void HandleZeroPosition(const char *startPos, unsigned posLen); 2265 2266 void HandleNullChar(const char *nullCharacter); 2267 2268 template <typename Range> 2269 static void EmitFormatDiagnostic(Sema &S, bool inFunctionCall, 2270 const Expr *ArgumentExpr, 2271 PartialDiagnostic PDiag, 2272 SourceLocation StringLoc, 2273 bool IsStringLocation, Range StringRange, 2274 ArrayRef<FixItHint> Fixit = None); 2275 2276protected: 2277 bool HandleInvalidConversionSpecifier(unsigned argIndex, SourceLocation Loc, 2278 const char *startSpec, 2279 unsigned specifierLen, 2280 const char *csStart, unsigned csLen); 2281 2282 void HandlePositionalNonpositionalArgs(SourceLocation Loc, 2283 const char *startSpec, 2284 unsigned specifierLen); 2285 2286 SourceRange getFormatStringRange(); 2287 CharSourceRange getSpecifierRange(const char *startSpecifier, 2288 unsigned specifierLen); 2289 SourceLocation getLocationOfByte(const char *x); 2290 2291 const Expr *getDataArg(unsigned i) const; 2292 2293 bool CheckNumArgs(const analyze_format_string::FormatSpecifier &FS, 2294 const analyze_format_string::ConversionSpecifier &CS, 2295 const char *startSpecifier, unsigned specifierLen, 2296 unsigned argIndex); 2297 2298 template <typename Range> 2299 void EmitFormatDiagnostic(PartialDiagnostic PDiag, SourceLocation StringLoc, 2300 bool IsStringLocation, Range StringRange, 2301 ArrayRef<FixItHint> Fixit = None); 2302 2303 void CheckPositionalAndNonpositionalArgs( 2304 const analyze_format_string::FormatSpecifier *FS); 2305}; 2306} 2307 2308SourceRange CheckFormatHandler::getFormatStringRange() { 2309 return OrigFormatExpr->getSourceRange(); 2310} 2311 2312CharSourceRange CheckFormatHandler:: 2313getSpecifierRange(const char *startSpecifier, unsigned specifierLen) { 2314 SourceLocation Start = getLocationOfByte(startSpecifier); 2315 SourceLocation End = getLocationOfByte(startSpecifier + specifierLen - 1); 2316 2317 // Advance the end SourceLocation by one due to half-open ranges. 2318 End = End.getLocWithOffset(1); 2319 2320 return CharSourceRange::getCharRange(Start, End); 2321} 2322 2323SourceLocation CheckFormatHandler::getLocationOfByte(const char *x) { 2324 return S.getLocationOfStringLiteralByte(FExpr, x - Beg); 2325} 2326 2327void CheckFormatHandler::HandleIncompleteSpecifier(const char *startSpecifier, 2328 unsigned specifierLen){ 2329 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_incomplete_specifier), 2330 getLocationOfByte(startSpecifier), 2331 /*IsStringLocation*/true, 2332 getSpecifierRange(startSpecifier, specifierLen)); 2333} 2334 2335void CheckFormatHandler::HandleInvalidLengthModifier( 2336 const analyze_format_string::FormatSpecifier &FS, 2337 const analyze_format_string::ConversionSpecifier &CS, 2338 const char *startSpecifier, unsigned specifierLen, unsigned DiagID) { 2339 using namespace analyze_format_string; 2340 2341 const LengthModifier &LM = FS.getLengthModifier(); 2342 CharSourceRange LMRange = getSpecifierRange(LM.getStart(), LM.getLength()); 2343 2344 // See if we know how to fix this length modifier. 2345 Optional<LengthModifier> FixedLM = FS.getCorrectedLengthModifier(); 2346 if (FixedLM) { 2347 EmitFormatDiagnostic(S.PDiag(DiagID) << LM.toString() << CS.toString(), 2348 getLocationOfByte(LM.getStart()), 2349 /*IsStringLocation*/true, 2350 getSpecifierRange(startSpecifier, specifierLen)); 2351 2352 S.Diag(getLocationOfByte(LM.getStart()), diag::note_format_fix_specifier) 2353 << FixedLM->toString() 2354 << FixItHint::CreateReplacement(LMRange, FixedLM->toString()); 2355 2356 } else { 2357 FixItHint Hint; 2358 if (DiagID == diag::warn_format_nonsensical_length) 2359 Hint = FixItHint::CreateRemoval(LMRange); 2360 2361 EmitFormatDiagnostic(S.PDiag(DiagID) << LM.toString() << CS.toString(), 2362 getLocationOfByte(LM.getStart()), 2363 /*IsStringLocation*/true, 2364 getSpecifierRange(startSpecifier, specifierLen), 2365 Hint); 2366 } 2367} 2368 2369void CheckFormatHandler::HandleNonStandardLengthModifier( 2370 const analyze_format_string::FormatSpecifier &FS, 2371 const char *startSpecifier, unsigned specifierLen) { 2372 using namespace analyze_format_string; 2373 2374 const LengthModifier &LM = FS.getLengthModifier(); 2375 CharSourceRange LMRange = getSpecifierRange(LM.getStart(), LM.getLength()); 2376 2377 // See if we know how to fix this length modifier. 2378 Optional<LengthModifier> FixedLM = FS.getCorrectedLengthModifier(); 2379 if (FixedLM) { 2380 EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard) 2381 << LM.toString() << 0, 2382 getLocationOfByte(LM.getStart()), 2383 /*IsStringLocation*/true, 2384 getSpecifierRange(startSpecifier, specifierLen)); 2385 2386 S.Diag(getLocationOfByte(LM.getStart()), diag::note_format_fix_specifier) 2387 << FixedLM->toString() 2388 << FixItHint::CreateReplacement(LMRange, FixedLM->toString()); 2389 2390 } else { 2391 EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard) 2392 << LM.toString() << 0, 2393 getLocationOfByte(LM.getStart()), 2394 /*IsStringLocation*/true, 2395 getSpecifierRange(startSpecifier, specifierLen)); 2396 } 2397} 2398 2399void CheckFormatHandler::HandleNonStandardConversionSpecifier( 2400 const analyze_format_string::ConversionSpecifier &CS, 2401 const char *startSpecifier, unsigned specifierLen) { 2402 using namespace analyze_format_string; 2403 2404 // See if we know how to fix this conversion specifier. 2405 Optional<ConversionSpecifier> FixedCS = CS.getStandardSpecifier(); 2406 if (FixedCS) { 2407 EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard) 2408 << CS.toString() << /*conversion specifier*/1, 2409 getLocationOfByte(CS.getStart()), 2410 /*IsStringLocation*/true, 2411 getSpecifierRange(startSpecifier, specifierLen)); 2412 2413 CharSourceRange CSRange = getSpecifierRange(CS.getStart(), CS.getLength()); 2414 S.Diag(getLocationOfByte(CS.getStart()), diag::note_format_fix_specifier) 2415 << FixedCS->toString() 2416 << FixItHint::CreateReplacement(CSRange, FixedCS->toString()); 2417 } else { 2418 EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard) 2419 << CS.toString() << /*conversion specifier*/1, 2420 getLocationOfByte(CS.getStart()), 2421 /*IsStringLocation*/true, 2422 getSpecifierRange(startSpecifier, specifierLen)); 2423 } 2424} 2425 2426void CheckFormatHandler::HandlePosition(const char *startPos, 2427 unsigned posLen) { 2428 EmitFormatDiagnostic(S.PDiag(diag::warn_format_non_standard_positional_arg), 2429 getLocationOfByte(startPos), 2430 /*IsStringLocation*/true, 2431 getSpecifierRange(startPos, posLen)); 2432} 2433 2434void 2435CheckFormatHandler::HandleInvalidPosition(const char *startPos, unsigned posLen, 2436 analyze_format_string::PositionContext p) { 2437 EmitFormatDiagnostic(S.PDiag(diag::warn_format_invalid_positional_specifier) 2438 << (unsigned) p, 2439 getLocationOfByte(startPos), /*IsStringLocation*/true, 2440 getSpecifierRange(startPos, posLen)); 2441} 2442 2443void CheckFormatHandler::HandleZeroPosition(const char *startPos, 2444 unsigned posLen) { 2445 EmitFormatDiagnostic(S.PDiag(diag::warn_format_zero_positional_specifier), 2446 getLocationOfByte(startPos), 2447 /*IsStringLocation*/true, 2448 getSpecifierRange(startPos, posLen)); 2449} 2450 2451void CheckFormatHandler::HandleNullChar(const char *nullCharacter) { 2452 if (!isa<ObjCStringLiteral>(OrigFormatExpr)) { 2453 // The presence of a null character is likely an error. 2454 EmitFormatDiagnostic( 2455 S.PDiag(diag::warn_printf_format_string_contains_null_char), 2456 getLocationOfByte(nullCharacter), /*IsStringLocation*/true, 2457 getFormatStringRange()); 2458 } 2459} 2460 2461// Note that this may return NULL if there was an error parsing or building 2462// one of the argument expressions. 2463const Expr *CheckFormatHandler::getDataArg(unsigned i) const { 2464 return Args[FirstDataArg + i]; 2465} 2466 2467void CheckFormatHandler::DoneProcessing() { 2468 // Does the number of data arguments exceed the number of 2469 // format conversions in the format string? 2470 if (!HasVAListArg) { 2471 // Find any arguments that weren't covered. 2472 CoveredArgs.flip(); 2473 signed notCoveredArg = CoveredArgs.find_first(); 2474 if (notCoveredArg >= 0) { 2475 assert((unsigned)notCoveredArg < NumDataArgs); 2476 if (const Expr *E = getDataArg((unsigned) notCoveredArg)) { 2477 SourceLocation Loc = E->getLocStart(); 2478 if (!S.getSourceManager().isInSystemMacro(Loc)) { 2479 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_data_arg_not_used), 2480 Loc, /*IsStringLocation*/false, 2481 getFormatStringRange()); 2482 } 2483 } 2484 } 2485 } 2486} 2487 2488bool 2489CheckFormatHandler::HandleInvalidConversionSpecifier(unsigned argIndex, 2490 SourceLocation Loc, 2491 const char *startSpec, 2492 unsigned specifierLen, 2493 const char *csStart, 2494 unsigned csLen) { 2495 2496 bool keepGoing = true; 2497 if (argIndex < NumDataArgs) { 2498 // Consider the argument coverered, even though the specifier doesn't 2499 // make sense. 2500 CoveredArgs.set(argIndex); 2501 } 2502 else { 2503 // If argIndex exceeds the number of data arguments we 2504 // don't issue a warning because that is just a cascade of warnings (and 2505 // they may have intended '%%' anyway). We don't want to continue processing 2506 // the format string after this point, however, as we will like just get 2507 // gibberish when trying to match arguments. 2508 keepGoing = false; 2509 } 2510 2511 EmitFormatDiagnostic(S.PDiag(diag::warn_format_invalid_conversion) 2512 << StringRef(csStart, csLen), 2513 Loc, /*IsStringLocation*/true, 2514 getSpecifierRange(startSpec, specifierLen)); 2515 2516 return keepGoing; 2517} 2518 2519void 2520CheckFormatHandler::HandlePositionalNonpositionalArgs(SourceLocation Loc, 2521 const char *startSpec, 2522 unsigned specifierLen) { 2523 EmitFormatDiagnostic( 2524 S.PDiag(diag::warn_format_mix_positional_nonpositional_args), 2525 Loc, /*isStringLoc*/true, getSpecifierRange(startSpec, specifierLen)); 2526} 2527 2528bool 2529CheckFormatHandler::CheckNumArgs( 2530 const analyze_format_string::FormatSpecifier &FS, 2531 const analyze_format_string::ConversionSpecifier &CS, 2532 const char *startSpecifier, unsigned specifierLen, unsigned argIndex) { 2533 2534 if (argIndex >= NumDataArgs) { 2535 PartialDiagnostic PDiag = FS.usesPositionalArg() 2536 ? (S.PDiag(diag::warn_printf_positional_arg_exceeds_data_args) 2537 << (argIndex+1) << NumDataArgs) 2538 : S.PDiag(diag::warn_printf_insufficient_data_args); 2539 EmitFormatDiagnostic( 2540 PDiag, getLocationOfByte(CS.getStart()), /*IsStringLocation*/true, 2541 getSpecifierRange(startSpecifier, specifierLen)); 2542 return false; 2543 } 2544 return true; 2545} 2546 2547template<typename Range> 2548void CheckFormatHandler::EmitFormatDiagnostic(PartialDiagnostic PDiag, 2549 SourceLocation Loc, 2550 bool IsStringLocation, 2551 Range StringRange, 2552 ArrayRef<FixItHint> FixIt) { 2553 EmitFormatDiagnostic(S, inFunctionCall, Args[FormatIdx], PDiag, 2554 Loc, IsStringLocation, StringRange, FixIt); 2555} 2556 2557/// \brief If the format string is not within the funcion call, emit a note 2558/// so that the function call and string are in diagnostic messages. 2559/// 2560/// \param InFunctionCall if true, the format string is within the function 2561/// call and only one diagnostic message will be produced. Otherwise, an 2562/// extra note will be emitted pointing to location of the format string. 2563/// 2564/// \param ArgumentExpr the expression that is passed as the format string 2565/// argument in the function call. Used for getting locations when two 2566/// diagnostics are emitted. 2567/// 2568/// \param PDiag the callee should already have provided any strings for the 2569/// diagnostic message. This function only adds locations and fixits 2570/// to diagnostics. 2571/// 2572/// \param Loc primary location for diagnostic. If two diagnostics are 2573/// required, one will be at Loc and a new SourceLocation will be created for 2574/// the other one. 2575/// 2576/// \param IsStringLocation if true, Loc points to the format string should be 2577/// used for the note. Otherwise, Loc points to the argument list and will 2578/// be used with PDiag. 2579/// 2580/// \param StringRange some or all of the string to highlight. This is 2581/// templated so it can accept either a CharSourceRange or a SourceRange. 2582/// 2583/// \param FixIt optional fix it hint for the format string. 2584template<typename Range> 2585void CheckFormatHandler::EmitFormatDiagnostic(Sema &S, bool InFunctionCall, 2586 const Expr *ArgumentExpr, 2587 PartialDiagnostic PDiag, 2588 SourceLocation Loc, 2589 bool IsStringLocation, 2590 Range StringRange, 2591 ArrayRef<FixItHint> FixIt) { 2592 if (InFunctionCall) { 2593 const Sema::SemaDiagnosticBuilder &D = S.Diag(Loc, PDiag); 2594 D << StringRange; 2595 for (ArrayRef<FixItHint>::iterator I = FixIt.begin(), E = FixIt.end(); 2596 I != E; ++I) { 2597 D << *I; 2598 } 2599 } else { 2600 S.Diag(IsStringLocation ? ArgumentExpr->getExprLoc() : Loc, PDiag) 2601 << ArgumentExpr->getSourceRange(); 2602 2603 const Sema::SemaDiagnosticBuilder &Note = 2604 S.Diag(IsStringLocation ? Loc : StringRange.getBegin(), 2605 diag::note_format_string_defined); 2606 2607 Note << StringRange; 2608 for (ArrayRef<FixItHint>::iterator I = FixIt.begin(), E = FixIt.end(); 2609 I != E; ++I) { 2610 Note << *I; 2611 } 2612 } 2613} 2614 2615//===--- CHECK: Printf format string checking ------------------------------===// 2616 2617namespace { 2618class CheckPrintfHandler : public CheckFormatHandler { 2619 bool ObjCContext; 2620public: 2621 CheckPrintfHandler(Sema &s, const StringLiteral *fexpr, 2622 const Expr *origFormatExpr, unsigned firstDataArg, 2623 unsigned numDataArgs, bool isObjC, 2624 const char *beg, bool hasVAListArg, 2625 ArrayRef<const Expr *> Args, 2626 unsigned formatIdx, bool inFunctionCall, 2627 Sema::VariadicCallType CallType) 2628 : CheckFormatHandler(s, fexpr, origFormatExpr, firstDataArg, 2629 numDataArgs, beg, hasVAListArg, Args, 2630 formatIdx, inFunctionCall, CallType), ObjCContext(isObjC) 2631 {} 2632 2633 2634 bool HandleInvalidPrintfConversionSpecifier( 2635 const analyze_printf::PrintfSpecifier &FS, 2636 const char *startSpecifier, 2637 unsigned specifierLen); 2638 2639 bool HandlePrintfSpecifier(const analyze_printf::PrintfSpecifier &FS, 2640 const char *startSpecifier, 2641 unsigned specifierLen); 2642 bool checkFormatExpr(const analyze_printf::PrintfSpecifier &FS, 2643 const char *StartSpecifier, 2644 unsigned SpecifierLen, 2645 const Expr *E); 2646 2647 bool HandleAmount(const analyze_format_string::OptionalAmount &Amt, unsigned k, 2648 const char *startSpecifier, unsigned specifierLen); 2649 void HandleInvalidAmount(const analyze_printf::PrintfSpecifier &FS, 2650 const analyze_printf::OptionalAmount &Amt, 2651 unsigned type, 2652 const char *startSpecifier, unsigned specifierLen); 2653 void HandleFlag(const analyze_printf::PrintfSpecifier &FS, 2654 const analyze_printf::OptionalFlag &flag, 2655 const char *startSpecifier, unsigned specifierLen); 2656 void HandleIgnoredFlag(const analyze_printf::PrintfSpecifier &FS, 2657 const analyze_printf::OptionalFlag &ignoredFlag, 2658 const analyze_printf::OptionalFlag &flag, 2659 const char *startSpecifier, unsigned specifierLen); 2660 bool checkForCStrMembers(const analyze_printf::ArgType &AT, 2661 const Expr *E, const CharSourceRange &CSR); 2662 2663}; 2664} 2665 2666bool CheckPrintfHandler::HandleInvalidPrintfConversionSpecifier( 2667 const analyze_printf::PrintfSpecifier &FS, 2668 const char *startSpecifier, 2669 unsigned specifierLen) { 2670 const analyze_printf::PrintfConversionSpecifier &CS = 2671 FS.getConversionSpecifier(); 2672 2673 return HandleInvalidConversionSpecifier(FS.getArgIndex(), 2674 getLocationOfByte(CS.getStart()), 2675 startSpecifier, specifierLen, 2676 CS.getStart(), CS.getLength()); 2677} 2678 2679bool CheckPrintfHandler::HandleAmount( 2680 const analyze_format_string::OptionalAmount &Amt, 2681 unsigned k, const char *startSpecifier, 2682 unsigned specifierLen) { 2683 2684 if (Amt.hasDataArgument()) { 2685 if (!HasVAListArg) { 2686 unsigned argIndex = Amt.getArgIndex(); 2687 if (argIndex >= NumDataArgs) { 2688 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_asterisk_missing_arg) 2689 << k, 2690 getLocationOfByte(Amt.getStart()), 2691 /*IsStringLocation*/true, 2692 getSpecifierRange(startSpecifier, specifierLen)); 2693 // Don't do any more checking. We will just emit 2694 // spurious errors. 2695 return false; 2696 } 2697 2698 // Type check the data argument. It should be an 'int'. 2699 // Although not in conformance with C99, we also allow the argument to be 2700 // an 'unsigned int' as that is a reasonably safe case. GCC also 2701 // doesn't emit a warning for that case. 2702 CoveredArgs.set(argIndex); 2703 const Expr *Arg = getDataArg(argIndex); 2704 if (!Arg) 2705 return false; 2706 2707 QualType T = Arg->getType(); 2708 2709 const analyze_printf::ArgType &AT = Amt.getArgType(S.Context); 2710 assert(AT.isValid()); 2711 2712 if (!AT.matchesType(S.Context, T)) { 2713 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_asterisk_wrong_type) 2714 << k << AT.getRepresentativeTypeName(S.Context) 2715 << T << Arg->getSourceRange(), 2716 getLocationOfByte(Amt.getStart()), 2717 /*IsStringLocation*/true, 2718 getSpecifierRange(startSpecifier, specifierLen)); 2719 // Don't do any more checking. We will just emit 2720 // spurious errors. 2721 return false; 2722 } 2723 } 2724 } 2725 return true; 2726} 2727 2728void CheckPrintfHandler::HandleInvalidAmount( 2729 const analyze_printf::PrintfSpecifier &FS, 2730 const analyze_printf::OptionalAmount &Amt, 2731 unsigned type, 2732 const char *startSpecifier, 2733 unsigned specifierLen) { 2734 const analyze_printf::PrintfConversionSpecifier &CS = 2735 FS.getConversionSpecifier(); 2736 2737 FixItHint fixit = 2738 Amt.getHowSpecified() == analyze_printf::OptionalAmount::Constant 2739 ? FixItHint::CreateRemoval(getSpecifierRange(Amt.getStart(), 2740 Amt.getConstantLength())) 2741 : FixItHint(); 2742 2743 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_nonsensical_optional_amount) 2744 << type << CS.toString(), 2745 getLocationOfByte(Amt.getStart()), 2746 /*IsStringLocation*/true, 2747 getSpecifierRange(startSpecifier, specifierLen), 2748 fixit); 2749} 2750 2751void CheckPrintfHandler::HandleFlag(const analyze_printf::PrintfSpecifier &FS, 2752 const analyze_printf::OptionalFlag &flag, 2753 const char *startSpecifier, 2754 unsigned specifierLen) { 2755 // Warn about pointless flag with a fixit removal. 2756 const analyze_printf::PrintfConversionSpecifier &CS = 2757 FS.getConversionSpecifier(); 2758 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_nonsensical_flag) 2759 << flag.toString() << CS.toString(), 2760 getLocationOfByte(flag.getPosition()), 2761 /*IsStringLocation*/true, 2762 getSpecifierRange(startSpecifier, specifierLen), 2763 FixItHint::CreateRemoval( 2764 getSpecifierRange(flag.getPosition(), 1))); 2765} 2766 2767void CheckPrintfHandler::HandleIgnoredFlag( 2768 const analyze_printf::PrintfSpecifier &FS, 2769 const analyze_printf::OptionalFlag &ignoredFlag, 2770 const analyze_printf::OptionalFlag &flag, 2771 const char *startSpecifier, 2772 unsigned specifierLen) { 2773 // Warn about ignored flag with a fixit removal. 2774 EmitFormatDiagnostic(S.PDiag(diag::warn_printf_ignored_flag) 2775 << ignoredFlag.toString() << flag.toString(), 2776 getLocationOfByte(ignoredFlag.getPosition()), 2777 /*IsStringLocation*/true, 2778 getSpecifierRange(startSpecifier, specifierLen), 2779 FixItHint::CreateRemoval( 2780 getSpecifierRange(ignoredFlag.getPosition(), 1))); 2781} 2782 2783// Determines if the specified is a C++ class or struct containing 2784// a member with the specified name and kind (e.g. a CXXMethodDecl named 2785// "c_str()"). 2786template<typename MemberKind> 2787static llvm::SmallPtrSet<MemberKind*, 1> 2788CXXRecordMembersNamed(StringRef Name, Sema &S, QualType Ty) { 2789 const RecordType *RT = Ty->getAs<RecordType>(); 2790 llvm::SmallPtrSet<MemberKind*, 1> Results; 2791 2792 if (!RT) 2793 return Results; 2794 const CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(RT->getDecl()); 2795 if (!RD) 2796 return Results; 2797 2798 LookupResult R(S, &S.PP.getIdentifierTable().get(Name), SourceLocation(), 2799 Sema::LookupMemberName); 2800 2801 // We just need to include all members of the right kind turned up by the 2802 // filter, at this point. 2803 if (S.LookupQualifiedName(R, RT->getDecl())) 2804 for (LookupResult::iterator I = R.begin(), E = R.end(); I != E; ++I) { 2805 NamedDecl *decl = (*I)->getUnderlyingDecl(); 2806 if (MemberKind *FK = dyn_cast<MemberKind>(decl)) 2807 Results.insert(FK); 2808 } 2809 return Results; 2810} 2811 2812// Check if a (w)string was passed when a (w)char* was needed, and offer a 2813// better diagnostic if so. AT is assumed to be valid. 2814// Returns true when a c_str() conversion method is found. 2815bool CheckPrintfHandler::checkForCStrMembers( 2816 const analyze_printf::ArgType &AT, const Expr *E, 2817 const CharSourceRange &CSR) { 2818 typedef llvm::SmallPtrSet<CXXMethodDecl*, 1> MethodSet; 2819 2820 MethodSet Results = 2821 CXXRecordMembersNamed<CXXMethodDecl>("c_str", S, E->getType()); 2822 2823 for (MethodSet::iterator MI = Results.begin(), ME = Results.end(); 2824 MI != ME; ++MI) { 2825 const CXXMethodDecl *Method = *MI; 2826 if (Method->getNumParams() == 0 && 2827 AT.matchesType(S.Context, Method->getResultType())) { 2828 // FIXME: Suggest parens if the expression needs them. 2829 SourceLocation EndLoc = 2830 S.getPreprocessor().getLocForEndOfToken(E->getLocEnd()); 2831 S.Diag(E->getLocStart(), diag::note_printf_c_str) 2832 << "c_str()" 2833 << FixItHint::CreateInsertion(EndLoc, ".c_str()"); 2834 return true; 2835 } 2836 } 2837 2838 return false; 2839} 2840 2841bool 2842CheckPrintfHandler::HandlePrintfSpecifier(const analyze_printf::PrintfSpecifier 2843 &FS, 2844 const char *startSpecifier, 2845 unsigned specifierLen) { 2846 2847 using namespace analyze_format_string; 2848 using namespace analyze_printf; 2849 const PrintfConversionSpecifier &CS = FS.getConversionSpecifier(); 2850 2851 if (FS.consumesDataArgument()) { 2852 if (atFirstArg) { 2853 atFirstArg = false; 2854 usesPositionalArgs = FS.usesPositionalArg(); 2855 } 2856 else if (usesPositionalArgs != FS.usesPositionalArg()) { 2857 HandlePositionalNonpositionalArgs(getLocationOfByte(CS.getStart()), 2858 startSpecifier, specifierLen); 2859 return false; 2860 } 2861 } 2862 2863 // First check if the field width, precision, and conversion specifier 2864 // have matching data arguments. 2865 if (!HandleAmount(FS.getFieldWidth(), /* field width */ 0, 2866 startSpecifier, specifierLen)) { 2867 return false; 2868 } 2869 2870 if (!HandleAmount(FS.getPrecision(), /* precision */ 1, 2871 startSpecifier, specifierLen)) { 2872 return false; 2873 } 2874 2875 if (!CS.consumesDataArgument()) { 2876 // FIXME: Technically specifying a precision or field width here 2877 // makes no sense. Worth issuing a warning at some point. 2878 return true; 2879 } 2880 2881 // Consume the argument. 2882 unsigned argIndex = FS.getArgIndex(); 2883 if (argIndex < NumDataArgs) { 2884 // The check to see if the argIndex is valid will come later. 2885 // We set the bit here because we may exit early from this 2886 // function if we encounter some other error. 2887 CoveredArgs.set(argIndex); 2888 } 2889 2890 // Check for using an Objective-C specific conversion specifier 2891 // in a non-ObjC literal. 2892 if (!ObjCContext && CS.isObjCArg()) { 2893 return HandleInvalidPrintfConversionSpecifier(FS, startSpecifier, 2894 specifierLen); 2895 } 2896 2897 // Check for invalid use of field width 2898 if (!FS.hasValidFieldWidth()) { 2899 HandleInvalidAmount(FS, FS.getFieldWidth(), /* field width */ 0, 2900 startSpecifier, specifierLen); 2901 } 2902 2903 // Check for invalid use of precision 2904 if (!FS.hasValidPrecision()) { 2905 HandleInvalidAmount(FS, FS.getPrecision(), /* precision */ 1, 2906 startSpecifier, specifierLen); 2907 } 2908 2909 // Check each flag does not conflict with any other component. 2910 if (!FS.hasValidThousandsGroupingPrefix()) 2911 HandleFlag(FS, FS.hasThousandsGrouping(), startSpecifier, specifierLen); 2912 if (!FS.hasValidLeadingZeros()) 2913 HandleFlag(FS, FS.hasLeadingZeros(), startSpecifier, specifierLen); 2914 if (!FS.hasValidPlusPrefix()) 2915 HandleFlag(FS, FS.hasPlusPrefix(), startSpecifier, specifierLen); 2916 if (!FS.hasValidSpacePrefix()) 2917 HandleFlag(FS, FS.hasSpacePrefix(), startSpecifier, specifierLen); 2918 if (!FS.hasValidAlternativeForm()) 2919 HandleFlag(FS, FS.hasAlternativeForm(), startSpecifier, specifierLen); 2920 if (!FS.hasValidLeftJustified()) 2921 HandleFlag(FS, FS.isLeftJustified(), startSpecifier, specifierLen); 2922 2923 // Check that flags are not ignored by another flag 2924 if (FS.hasSpacePrefix() && FS.hasPlusPrefix()) // ' ' ignored by '+' 2925 HandleIgnoredFlag(FS, FS.hasSpacePrefix(), FS.hasPlusPrefix(), 2926 startSpecifier, specifierLen); 2927 if (FS.hasLeadingZeros() && FS.isLeftJustified()) // '0' ignored by '-' 2928 HandleIgnoredFlag(FS, FS.hasLeadingZeros(), FS.isLeftJustified(), 2929 startSpecifier, specifierLen); 2930 2931 // Check the length modifier is valid with the given conversion specifier. 2932 if (!FS.hasValidLengthModifier(S.getASTContext().getTargetInfo())) 2933 HandleInvalidLengthModifier(FS, CS, startSpecifier, specifierLen, 2934 diag::warn_format_nonsensical_length); 2935 else if (!FS.hasStandardLengthModifier()) 2936 HandleNonStandardLengthModifier(FS, startSpecifier, specifierLen); 2937 else if (!FS.hasStandardLengthConversionCombination()) 2938 HandleInvalidLengthModifier(FS, CS, startSpecifier, specifierLen, 2939 diag::warn_format_non_standard_conversion_spec); 2940 2941 if (!FS.hasStandardConversionSpecifier(S.getLangOpts())) 2942 HandleNonStandardConversionSpecifier(CS, startSpecifier, specifierLen); 2943 2944 // The remaining checks depend on the data arguments. 2945 if (HasVAListArg) 2946 return true; 2947 2948 if (!CheckNumArgs(FS, CS, startSpecifier, specifierLen, argIndex)) 2949 return false; 2950 2951 const Expr *Arg = getDataArg(argIndex); 2952 if (!Arg) 2953 return true; 2954 2955 return checkFormatExpr(FS, startSpecifier, specifierLen, Arg); 2956} 2957 2958static bool requiresParensToAddCast(const Expr *E) { 2959 // FIXME: We should have a general way to reason about operator 2960 // precedence and whether parens are actually needed here. 2961 // Take care of a few common cases where they aren't. 2962 const Expr *Inside = E->IgnoreImpCasts(); 2963 if (const PseudoObjectExpr *POE = dyn_cast<PseudoObjectExpr>(Inside)) 2964 Inside = POE->getSyntacticForm()->IgnoreImpCasts(); 2965 2966 switch (Inside->getStmtClass()) { 2967 case Stmt::ArraySubscriptExprClass: 2968 case Stmt::CallExprClass: 2969 case Stmt::CharacterLiteralClass: 2970 case Stmt::CXXBoolLiteralExprClass: 2971 case Stmt::DeclRefExprClass: 2972 case Stmt::FloatingLiteralClass: 2973 case Stmt::IntegerLiteralClass: 2974 case Stmt::MemberExprClass: 2975 case Stmt::ObjCArrayLiteralClass: 2976 case Stmt::ObjCBoolLiteralExprClass: 2977 case Stmt::ObjCBoxedExprClass: 2978 case Stmt::ObjCDictionaryLiteralClass: 2979 case Stmt::ObjCEncodeExprClass: 2980 case Stmt::ObjCIvarRefExprClass: 2981 case Stmt::ObjCMessageExprClass: 2982 case Stmt::ObjCPropertyRefExprClass: 2983 case Stmt::ObjCStringLiteralClass: 2984 case Stmt::ObjCSubscriptRefExprClass: 2985 case Stmt::ParenExprClass: 2986 case Stmt::StringLiteralClass: 2987 case Stmt::UnaryOperatorClass: 2988 return false; 2989 default: 2990 return true; 2991 } 2992} 2993 2994bool 2995CheckPrintfHandler::checkFormatExpr(const analyze_printf::PrintfSpecifier &FS, 2996 const char *StartSpecifier, 2997 unsigned SpecifierLen, 2998 const Expr *E) { 2999 using namespace analyze_format_string; 3000 using namespace analyze_printf; 3001 // Now type check the data expression that matches the 3002 // format specifier. 3003 const analyze_printf::ArgType &AT = FS.getArgType(S.Context, 3004 ObjCContext); 3005 if (!AT.isValid()) 3006 return true; 3007 3008 QualType ExprTy = E->getType(); 3009 while (const TypeOfExprType *TET = dyn_cast<TypeOfExprType>(ExprTy)) { 3010 ExprTy = TET->getUnderlyingExpr()->getType(); 3011 } 3012 3013 if (AT.matchesType(S.Context, ExprTy)) 3014 return true; 3015 3016 // Look through argument promotions for our error message's reported type. 3017 // This includes the integral and floating promotions, but excludes array 3018 // and function pointer decay; seeing that an argument intended to be a 3019 // string has type 'char [6]' is probably more confusing than 'char *'. 3020 if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) { 3021 if (ICE->getCastKind() == CK_IntegralCast || 3022 ICE->getCastKind() == CK_FloatingCast) { 3023 E = ICE->getSubExpr(); 3024 ExprTy = E->getType(); 3025 3026 // Check if we didn't match because of an implicit cast from a 'char' 3027 // or 'short' to an 'int'. This is done because printf is a varargs 3028 // function. 3029 if (ICE->getType() == S.Context.IntTy || 3030 ICE->getType() == S.Context.UnsignedIntTy) { 3031 // All further checking is done on the subexpression. 3032 if (AT.matchesType(S.Context, ExprTy)) 3033 return true; 3034 } 3035 } 3036 } else if (const CharacterLiteral *CL = dyn_cast<CharacterLiteral>(E)) { 3037 // Special case for 'a', which has type 'int' in C. 3038 // Note, however, that we do /not/ want to treat multibyte constants like 3039 // 'MooV' as characters! This form is deprecated but still exists. 3040 if (ExprTy == S.Context.IntTy) 3041 if (llvm::isUIntN(S.Context.getCharWidth(), CL->getValue())) 3042 ExprTy = S.Context.CharTy; 3043 } 3044 3045 // %C in an Objective-C context prints a unichar, not a wchar_t. 3046 // If the argument is an integer of some kind, believe the %C and suggest 3047 // a cast instead of changing the conversion specifier. 3048 QualType IntendedTy = ExprTy; 3049 if (ObjCContext && 3050 FS.getConversionSpecifier().getKind() == ConversionSpecifier::CArg) { 3051 if (ExprTy->isIntegralOrUnscopedEnumerationType() && 3052 !ExprTy->isCharType()) { 3053 // 'unichar' is defined as a typedef of unsigned short, but we should 3054 // prefer using the typedef if it is visible. 3055 IntendedTy = S.Context.UnsignedShortTy; 3056 3057 LookupResult Result(S, &S.Context.Idents.get("unichar"), E->getLocStart(), 3058 Sema::LookupOrdinaryName); 3059 if (S.LookupName(Result, S.getCurScope())) { 3060 NamedDecl *ND = Result.getFoundDecl(); 3061 if (TypedefNameDecl *TD = dyn_cast<TypedefNameDecl>(ND)) 3062 if (TD->getUnderlyingType() == IntendedTy) 3063 IntendedTy = S.Context.getTypedefType(TD); 3064 } 3065 } 3066 } 3067 3068 // Special-case some of Darwin's platform-independence types by suggesting 3069 // casts to primitive types that are known to be large enough. 3070 bool ShouldNotPrintDirectly = false; 3071 if (S.Context.getTargetInfo().getTriple().isOSDarwin()) { 3072 // Use a 'while' to peel off layers of typedefs. 3073 QualType TyTy = IntendedTy; 3074 while (const TypedefType *UserTy = TyTy->getAs<TypedefType>()) { 3075 StringRef Name = UserTy->getDecl()->getName(); 3076 QualType CastTy = llvm::StringSwitch<QualType>(Name) 3077 .Case("NSInteger", S.Context.LongTy) 3078 .Case("NSUInteger", S.Context.UnsignedLongTy) 3079 .Case("SInt32", S.Context.IntTy) 3080 .Case("UInt32", S.Context.UnsignedIntTy) 3081 .Default(QualType()); 3082 3083 if (!CastTy.isNull()) { 3084 ShouldNotPrintDirectly = true; 3085 IntendedTy = CastTy; 3086 break; 3087 } 3088 TyTy = UserTy->desugar(); 3089 } 3090 } 3091 3092 // We may be able to offer a FixItHint if it is a supported type. 3093 PrintfSpecifier fixedFS = FS; 3094 bool success = fixedFS.fixType(IntendedTy, S.getLangOpts(), 3095 S.Context, ObjCContext); 3096 3097 if (success) { 3098 // Get the fix string from the fixed format specifier 3099 SmallString<16> buf; 3100 llvm::raw_svector_ostream os(buf); 3101 fixedFS.toString(os); 3102 3103 CharSourceRange SpecRange = getSpecifierRange(StartSpecifier, SpecifierLen); 3104 3105 if (IntendedTy == ExprTy) { 3106 // In this case, the specifier is wrong and should be changed to match 3107 // the argument. 3108 EmitFormatDiagnostic( 3109 S.PDiag(diag::warn_printf_conversion_argument_type_mismatch) 3110 << AT.getRepresentativeTypeName(S.Context) << IntendedTy 3111 << E->getSourceRange(), 3112 E->getLocStart(), 3113 /*IsStringLocation*/false, 3114 SpecRange, 3115 FixItHint::CreateReplacement(SpecRange, os.str())); 3116 3117 } else { 3118 // The canonical type for formatting this value is different from the 3119 // actual type of the expression. (This occurs, for example, with Darwin's 3120 // NSInteger on 32-bit platforms, where it is typedef'd as 'int', but 3121 // should be printed as 'long' for 64-bit compatibility.) 3122 // Rather than emitting a normal format/argument mismatch, we want to 3123 // add a cast to the recommended type (and correct the format string 3124 // if necessary). 3125 SmallString<16> CastBuf; 3126 llvm::raw_svector_ostream CastFix(CastBuf); 3127 CastFix << "("; 3128 IntendedTy.print(CastFix, S.Context.getPrintingPolicy()); 3129 CastFix << ")"; 3130 3131 SmallVector<FixItHint,4> Hints; 3132 if (!AT.matchesType(S.Context, IntendedTy)) 3133 Hints.push_back(FixItHint::CreateReplacement(SpecRange, os.str())); 3134 3135 if (const CStyleCastExpr *CCast = dyn_cast<CStyleCastExpr>(E)) { 3136 // If there's already a cast present, just replace it. 3137 SourceRange CastRange(CCast->getLParenLoc(), CCast->getRParenLoc()); 3138 Hints.push_back(FixItHint::CreateReplacement(CastRange, CastFix.str())); 3139 3140 } else if (!requiresParensToAddCast(E)) { 3141 // If the expression has high enough precedence, 3142 // just write the C-style cast. 3143 Hints.push_back(FixItHint::CreateInsertion(E->getLocStart(), 3144 CastFix.str())); 3145 } else { 3146 // Otherwise, add parens around the expression as well as the cast. 3147 CastFix << "("; 3148 Hints.push_back(FixItHint::CreateInsertion(E->getLocStart(), 3149 CastFix.str())); 3150 3151 SourceLocation After = S.PP.getLocForEndOfToken(E->getLocEnd()); 3152 Hints.push_back(FixItHint::CreateInsertion(After, ")")); 3153 } 3154 3155 if (ShouldNotPrintDirectly) { 3156 // The expression has a type that should not be printed directly. 3157 // We extract the name from the typedef because we don't want to show 3158 // the underlying type in the diagnostic. 3159 StringRef Name = cast<TypedefType>(ExprTy)->getDecl()->getName(); 3160 3161 EmitFormatDiagnostic(S.PDiag(diag::warn_format_argument_needs_cast) 3162 << Name << IntendedTy 3163 << E->getSourceRange(), 3164 E->getLocStart(), /*IsStringLocation=*/false, 3165 SpecRange, Hints); 3166 } else { 3167 // In this case, the expression could be printed using a different 3168 // specifier, but we've decided that the specifier is probably correct 3169 // and we should cast instead. Just use the normal warning message. 3170 EmitFormatDiagnostic( 3171 S.PDiag(diag::warn_printf_conversion_argument_type_mismatch) 3172 << AT.getRepresentativeTypeName(S.Context) << ExprTy 3173 << E->getSourceRange(), 3174 E->getLocStart(), /*IsStringLocation*/false, 3175 SpecRange, Hints); 3176 } 3177 } 3178 } else { 3179 const CharSourceRange &CSR = getSpecifierRange(StartSpecifier, 3180 SpecifierLen); 3181 // Since the warning for passing non-POD types to variadic functions 3182 // was deferred until now, we emit a warning for non-POD 3183 // arguments here. 3184 if (S.isValidVarArgType(ExprTy) == Sema::VAK_Invalid) { 3185 unsigned DiagKind; 3186 if (ExprTy->isObjCObjectType()) 3187 DiagKind = diag::err_cannot_pass_objc_interface_to_vararg_format; 3188 else 3189 DiagKind = diag::warn_non_pod_vararg_with_format_string; 3190 3191 EmitFormatDiagnostic( 3192 S.PDiag(DiagKind) 3193 << S.getLangOpts().CPlusPlus11 3194 << ExprTy 3195 << CallType 3196 << AT.getRepresentativeTypeName(S.Context) 3197 << CSR 3198 << E->getSourceRange(), 3199 E->getLocStart(), /*IsStringLocation*/false, CSR); 3200 3201 checkForCStrMembers(AT, E, CSR); 3202 } else 3203 EmitFormatDiagnostic( 3204 S.PDiag(diag::warn_printf_conversion_argument_type_mismatch) 3205 << AT.getRepresentativeTypeName(S.Context) << ExprTy 3206 << CSR 3207 << E->getSourceRange(), 3208 E->getLocStart(), /*IsStringLocation*/false, CSR); 3209 } 3210 3211 return true; 3212} 3213 3214//===--- CHECK: Scanf format string checking ------------------------------===// 3215 3216namespace { 3217class CheckScanfHandler : public CheckFormatHandler { 3218public: 3219 CheckScanfHandler(Sema &s, const StringLiteral *fexpr, 3220 const Expr *origFormatExpr, unsigned firstDataArg, 3221 unsigned numDataArgs, const char *beg, bool hasVAListArg, 3222 ArrayRef<const Expr *> Args, 3223 unsigned formatIdx, bool inFunctionCall, 3224 Sema::VariadicCallType CallType) 3225 : CheckFormatHandler(s, fexpr, origFormatExpr, firstDataArg, 3226 numDataArgs, beg, hasVAListArg, 3227 Args, formatIdx, inFunctionCall, CallType) 3228 {} 3229 3230 bool HandleScanfSpecifier(const analyze_scanf::ScanfSpecifier &FS, 3231 const char *startSpecifier, 3232 unsigned specifierLen); 3233 3234 bool HandleInvalidScanfConversionSpecifier( 3235 const analyze_scanf::ScanfSpecifier &FS, 3236 const char *startSpecifier, 3237 unsigned specifierLen); 3238 3239 void HandleIncompleteScanList(const char *start, const char *end); 3240}; 3241} 3242 3243void CheckScanfHandler::HandleIncompleteScanList(const char *start, 3244 const char *end) { 3245 EmitFormatDiagnostic(S.PDiag(diag::warn_scanf_scanlist_incomplete), 3246 getLocationOfByte(end), /*IsStringLocation*/true, 3247 getSpecifierRange(start, end - start)); 3248} 3249 3250bool CheckScanfHandler::HandleInvalidScanfConversionSpecifier( 3251 const analyze_scanf::ScanfSpecifier &FS, 3252 const char *startSpecifier, 3253 unsigned specifierLen) { 3254 3255 const analyze_scanf::ScanfConversionSpecifier &CS = 3256 FS.getConversionSpecifier(); 3257 3258 return HandleInvalidConversionSpecifier(FS.getArgIndex(), 3259 getLocationOfByte(CS.getStart()), 3260 startSpecifier, specifierLen, 3261 CS.getStart(), CS.getLength()); 3262} 3263 3264bool CheckScanfHandler::HandleScanfSpecifier( 3265 const analyze_scanf::ScanfSpecifier &FS, 3266 const char *startSpecifier, 3267 unsigned specifierLen) { 3268 3269 using namespace analyze_scanf; 3270 using namespace analyze_format_string; 3271 3272 const ScanfConversionSpecifier &CS = FS.getConversionSpecifier(); 3273 3274 // Handle case where '%' and '*' don't consume an argument. These shouldn't 3275 // be used to decide if we are using positional arguments consistently. 3276 if (FS.consumesDataArgument()) { 3277 if (atFirstArg) { 3278 atFirstArg = false; 3279 usesPositionalArgs = FS.usesPositionalArg(); 3280 } 3281 else if (usesPositionalArgs != FS.usesPositionalArg()) { 3282 HandlePositionalNonpositionalArgs(getLocationOfByte(CS.getStart()), 3283 startSpecifier, specifierLen); 3284 return false; 3285 } 3286 } 3287 3288 // Check if the field with is non-zero. 3289 const OptionalAmount &Amt = FS.getFieldWidth(); 3290 if (Amt.getHowSpecified() == OptionalAmount::Constant) { 3291 if (Amt.getConstantAmount() == 0) { 3292 const CharSourceRange &R = getSpecifierRange(Amt.getStart(), 3293 Amt.getConstantLength()); 3294 EmitFormatDiagnostic(S.PDiag(diag::warn_scanf_nonzero_width), 3295 getLocationOfByte(Amt.getStart()), 3296 /*IsStringLocation*/true, R, 3297 FixItHint::CreateRemoval(R)); 3298 } 3299 } 3300 3301 if (!FS.consumesDataArgument()) { 3302 // FIXME: Technically specifying a precision or field width here 3303 // makes no sense. Worth issuing a warning at some point. 3304 return true; 3305 } 3306 3307 // Consume the argument. 3308 unsigned argIndex = FS.getArgIndex(); 3309 if (argIndex < NumDataArgs) { 3310 // The check to see if the argIndex is valid will come later. 3311 // We set the bit here because we may exit early from this 3312 // function if we encounter some other error. 3313 CoveredArgs.set(argIndex); 3314 } 3315 3316 // Check the length modifier is valid with the given conversion specifier. 3317 if (!FS.hasValidLengthModifier(S.getASTContext().getTargetInfo())) 3318 HandleInvalidLengthModifier(FS, CS, startSpecifier, specifierLen, 3319 diag::warn_format_nonsensical_length); 3320 else if (!FS.hasStandardLengthModifier()) 3321 HandleNonStandardLengthModifier(FS, startSpecifier, specifierLen); 3322 else if (!FS.hasStandardLengthConversionCombination()) 3323 HandleInvalidLengthModifier(FS, CS, startSpecifier, specifierLen, 3324 diag::warn_format_non_standard_conversion_spec); 3325 3326 if (!FS.hasStandardConversionSpecifier(S.getLangOpts())) 3327 HandleNonStandardConversionSpecifier(CS, startSpecifier, specifierLen); 3328 3329 // The remaining checks depend on the data arguments. 3330 if (HasVAListArg) 3331 return true; 3332 3333 if (!CheckNumArgs(FS, CS, startSpecifier, specifierLen, argIndex)) 3334 return false; 3335 3336 // Check that the argument type matches the format specifier. 3337 const Expr *Ex = getDataArg(argIndex); 3338 if (!Ex) 3339 return true; 3340 3341 const analyze_format_string::ArgType &AT = FS.getArgType(S.Context); 3342 if (AT.isValid() && !AT.matchesType(S.Context, Ex->getType())) { 3343 ScanfSpecifier fixedFS = FS; 3344 bool success = fixedFS.fixType(Ex->getType(), S.getLangOpts(), 3345 S.Context); 3346 3347 if (success) { 3348 // Get the fix string from the fixed format specifier. 3349 SmallString<128> buf; 3350 llvm::raw_svector_ostream os(buf); 3351 fixedFS.toString(os); 3352 3353 EmitFormatDiagnostic( 3354 S.PDiag(diag::warn_printf_conversion_argument_type_mismatch) 3355 << AT.getRepresentativeTypeName(S.Context) << Ex->getType() 3356 << Ex->getSourceRange(), 3357 Ex->getLocStart(), 3358 /*IsStringLocation*/false, 3359 getSpecifierRange(startSpecifier, specifierLen), 3360 FixItHint::CreateReplacement( 3361 getSpecifierRange(startSpecifier, specifierLen), 3362 os.str())); 3363 } else { 3364 EmitFormatDiagnostic( 3365 S.PDiag(diag::warn_printf_conversion_argument_type_mismatch) 3366 << AT.getRepresentativeTypeName(S.Context) << Ex->getType() 3367 << Ex->getSourceRange(), 3368 Ex->getLocStart(), 3369 /*IsStringLocation*/false, 3370 getSpecifierRange(startSpecifier, specifierLen)); 3371 } 3372 } 3373 3374 return true; 3375} 3376 3377void Sema::CheckFormatString(const StringLiteral *FExpr, 3378 const Expr *OrigFormatExpr, 3379 ArrayRef<const Expr *> Args, 3380 bool HasVAListArg, unsigned format_idx, 3381 unsigned firstDataArg, FormatStringType Type, 3382 bool inFunctionCall, VariadicCallType CallType) { 3383 3384 // CHECK: is the format string a wide literal? 3385 if (!FExpr->isAscii() && !FExpr->isUTF8()) { 3386 CheckFormatHandler::EmitFormatDiagnostic( 3387 *this, inFunctionCall, Args[format_idx], 3388 PDiag(diag::warn_format_string_is_wide_literal), FExpr->getLocStart(), 3389 /*IsStringLocation*/true, OrigFormatExpr->getSourceRange()); 3390 return; 3391 } 3392 3393 // Str - The format string. NOTE: this is NOT null-terminated! 3394 StringRef StrRef = FExpr->getString(); 3395 const char *Str = StrRef.data(); 3396 unsigned StrLen = StrRef.size(); 3397 const unsigned numDataArgs = Args.size() - firstDataArg; 3398 3399 // CHECK: empty format string? 3400 if (StrLen == 0 && numDataArgs > 0) { 3401 CheckFormatHandler::EmitFormatDiagnostic( 3402 *this, inFunctionCall, Args[format_idx], 3403 PDiag(diag::warn_empty_format_string), FExpr->getLocStart(), 3404 /*IsStringLocation*/true, OrigFormatExpr->getSourceRange()); 3405 return; 3406 } 3407 3408 if (Type == FST_Printf || Type == FST_NSString) { 3409 CheckPrintfHandler H(*this, FExpr, OrigFormatExpr, firstDataArg, 3410 numDataArgs, (Type == FST_NSString), 3411 Str, HasVAListArg, Args, format_idx, 3412 inFunctionCall, CallType); 3413 3414 if (!analyze_format_string::ParsePrintfString(H, Str, Str + StrLen, 3415 getLangOpts(), 3416 Context.getTargetInfo())) 3417 H.DoneProcessing(); 3418 } else if (Type == FST_Scanf) { 3419 CheckScanfHandler H(*this, FExpr, OrigFormatExpr, firstDataArg, numDataArgs, 3420 Str, HasVAListArg, Args, format_idx, 3421 inFunctionCall, CallType); 3422 3423 if (!analyze_format_string::ParseScanfString(H, Str, Str + StrLen, 3424 getLangOpts(), 3425 Context.getTargetInfo())) 3426 H.DoneProcessing(); 3427 } // TODO: handle other formats 3428} 3429 3430//===--- CHECK: Standard memory functions ---------------------------------===// 3431 3432/// \brief Determine whether the given type is a dynamic class type (e.g., 3433/// whether it has a vtable). 3434static bool isDynamicClassType(QualType T) { 3435 if (CXXRecordDecl *Record = T->getAsCXXRecordDecl()) 3436 if (CXXRecordDecl *Definition = Record->getDefinition()) 3437 if (Definition->isDynamicClass()) 3438 return true; 3439 3440 return false; 3441} 3442 3443/// \brief If E is a sizeof expression, returns its argument expression, 3444/// otherwise returns NULL. 3445static const Expr *getSizeOfExprArg(const Expr* E) { 3446 if (const UnaryExprOrTypeTraitExpr *SizeOf = 3447 dyn_cast<UnaryExprOrTypeTraitExpr>(E)) 3448 if (SizeOf->getKind() == clang::UETT_SizeOf && !SizeOf->isArgumentType()) 3449 return SizeOf->getArgumentExpr()->IgnoreParenImpCasts(); 3450 3451 return 0; 3452} 3453 3454/// \brief If E is a sizeof expression, returns its argument type. 3455static QualType getSizeOfArgType(const Expr* E) { 3456 if (const UnaryExprOrTypeTraitExpr *SizeOf = 3457 dyn_cast<UnaryExprOrTypeTraitExpr>(E)) 3458 if (SizeOf->getKind() == clang::UETT_SizeOf) 3459 return SizeOf->getTypeOfArgument(); 3460 3461 return QualType(); 3462} 3463 3464/// \brief Check for dangerous or invalid arguments to memset(). 3465/// 3466/// This issues warnings on known problematic, dangerous or unspecified 3467/// arguments to the standard 'memset', 'memcpy', 'memmove', and 'memcmp' 3468/// function calls. 3469/// 3470/// \param Call The call expression to diagnose. 3471void Sema::CheckMemaccessArguments(const CallExpr *Call, 3472 unsigned BId, 3473 IdentifierInfo *FnName) { 3474 assert(BId != 0); 3475 3476 // It is possible to have a non-standard definition of memset. Validate 3477 // we have enough arguments, and if not, abort further checking. 3478 unsigned ExpectedNumArgs = (BId == Builtin::BIstrndup ? 2 : 3); 3479 if (Call->getNumArgs() < ExpectedNumArgs) 3480 return; 3481 3482 unsigned LastArg = (BId == Builtin::BImemset || 3483 BId == Builtin::BIstrndup ? 1 : 2); 3484 unsigned LenArg = (BId == Builtin::BIstrndup ? 1 : 2); 3485 const Expr *LenExpr = Call->getArg(LenArg)->IgnoreParenImpCasts(); 3486 3487 // We have special checking when the length is a sizeof expression. 3488 QualType SizeOfArgTy = getSizeOfArgType(LenExpr); 3489 const Expr *SizeOfArg = getSizeOfExprArg(LenExpr); 3490 llvm::FoldingSetNodeID SizeOfArgID; 3491 3492 for (unsigned ArgIdx = 0; ArgIdx != LastArg; ++ArgIdx) { 3493 const Expr *Dest = Call->getArg(ArgIdx)->IgnoreParenImpCasts(); 3494 SourceRange ArgRange = Call->getArg(ArgIdx)->getSourceRange(); 3495 3496 QualType DestTy = Dest->getType(); 3497 if (const PointerType *DestPtrTy = DestTy->getAs<PointerType>()) { 3498 QualType PointeeTy = DestPtrTy->getPointeeType(); 3499 3500 // Never warn about void type pointers. This can be used to suppress 3501 // false positives. 3502 if (PointeeTy->isVoidType()) 3503 continue; 3504 3505 // Catch "memset(p, 0, sizeof(p))" -- needs to be sizeof(*p). Do this by 3506 // actually comparing the expressions for equality. Because computing the 3507 // expression IDs can be expensive, we only do this if the diagnostic is 3508 // enabled. 3509 if (SizeOfArg && 3510 Diags.getDiagnosticLevel(diag::warn_sizeof_pointer_expr_memaccess, 3511 SizeOfArg->getExprLoc())) { 3512 // We only compute IDs for expressions if the warning is enabled, and 3513 // cache the sizeof arg's ID. 3514 if (SizeOfArgID == llvm::FoldingSetNodeID()) 3515 SizeOfArg->Profile(SizeOfArgID, Context, true); 3516 llvm::FoldingSetNodeID DestID; 3517 Dest->Profile(DestID, Context, true); 3518 if (DestID == SizeOfArgID) { 3519 // TODO: For strncpy() and friends, this could suggest sizeof(dst) 3520 // over sizeof(src) as well. 3521 unsigned ActionIdx = 0; // Default is to suggest dereferencing. 3522 StringRef ReadableName = FnName->getName(); 3523 3524 if (const UnaryOperator *UnaryOp = dyn_cast<UnaryOperator>(Dest)) 3525 if (UnaryOp->getOpcode() == UO_AddrOf) 3526 ActionIdx = 1; // If its an address-of operator, just remove it. 3527 if (!PointeeTy->isIncompleteType() && 3528 (Context.getTypeSize(PointeeTy) == Context.getCharWidth())) 3529 ActionIdx = 2; // If the pointee's size is sizeof(char), 3530 // suggest an explicit length. 3531 3532 // If the function is defined as a builtin macro, do not show macro 3533 // expansion. 3534 SourceLocation SL = SizeOfArg->getExprLoc(); 3535 SourceRange DSR = Dest->getSourceRange(); 3536 SourceRange SSR = SizeOfArg->getSourceRange(); 3537 SourceManager &SM = PP.getSourceManager(); 3538 3539 if (SM.isMacroArgExpansion(SL)) { 3540 ReadableName = Lexer::getImmediateMacroName(SL, SM, LangOpts); 3541 SL = SM.getSpellingLoc(SL); 3542 DSR = SourceRange(SM.getSpellingLoc(DSR.getBegin()), 3543 SM.getSpellingLoc(DSR.getEnd())); 3544 SSR = SourceRange(SM.getSpellingLoc(SSR.getBegin()), 3545 SM.getSpellingLoc(SSR.getEnd())); 3546 } 3547 3548 DiagRuntimeBehavior(SL, SizeOfArg, 3549 PDiag(diag::warn_sizeof_pointer_expr_memaccess) 3550 << ReadableName 3551 << PointeeTy 3552 << DestTy 3553 << DSR 3554 << SSR); 3555 DiagRuntimeBehavior(SL, SizeOfArg, 3556 PDiag(diag::warn_sizeof_pointer_expr_memaccess_note) 3557 << ActionIdx 3558 << SSR); 3559 3560 break; 3561 } 3562 } 3563 3564 // Also check for cases where the sizeof argument is the exact same 3565 // type as the memory argument, and where it points to a user-defined 3566 // record type. 3567 if (SizeOfArgTy != QualType()) { 3568 if (PointeeTy->isRecordType() && 3569 Context.typesAreCompatible(SizeOfArgTy, DestTy)) { 3570 DiagRuntimeBehavior(LenExpr->getExprLoc(), Dest, 3571 PDiag(diag::warn_sizeof_pointer_type_memaccess) 3572 << FnName << SizeOfArgTy << ArgIdx 3573 << PointeeTy << Dest->getSourceRange() 3574 << LenExpr->getSourceRange()); 3575 break; 3576 } 3577 } 3578 3579 // Always complain about dynamic classes. 3580 if (isDynamicClassType(PointeeTy)) { 3581 3582 unsigned OperationType = 0; 3583 // "overwritten" if we're warning about the destination for any call 3584 // but memcmp; otherwise a verb appropriate to the call. 3585 if (ArgIdx != 0 || BId == Builtin::BImemcmp) { 3586 if (BId == Builtin::BImemcpy) 3587 OperationType = 1; 3588 else if(BId == Builtin::BImemmove) 3589 OperationType = 2; 3590 else if (BId == Builtin::BImemcmp) 3591 OperationType = 3; 3592 } 3593 3594 DiagRuntimeBehavior( 3595 Dest->getExprLoc(), Dest, 3596 PDiag(diag::warn_dyn_class_memaccess) 3597 << (BId == Builtin::BImemcmp ? ArgIdx + 2 : ArgIdx) 3598 << FnName << PointeeTy 3599 << OperationType 3600 << Call->getCallee()->getSourceRange()); 3601 } else if (PointeeTy.hasNonTrivialObjCLifetime() && 3602 BId != Builtin::BImemset) 3603 DiagRuntimeBehavior( 3604 Dest->getExprLoc(), Dest, 3605 PDiag(diag::warn_arc_object_memaccess) 3606 << ArgIdx << FnName << PointeeTy 3607 << Call->getCallee()->getSourceRange()); 3608 else 3609 continue; 3610 3611 DiagRuntimeBehavior( 3612 Dest->getExprLoc(), Dest, 3613 PDiag(diag::note_bad_memaccess_silence) 3614 << FixItHint::CreateInsertion(ArgRange.getBegin(), "(void*)")); 3615 break; 3616 } 3617 } 3618} 3619 3620// A little helper routine: ignore addition and subtraction of integer literals. 3621// This intentionally does not ignore all integer constant expressions because 3622// we don't want to remove sizeof(). 3623static const Expr *ignoreLiteralAdditions(const Expr *Ex, ASTContext &Ctx) { 3624 Ex = Ex->IgnoreParenCasts(); 3625 3626 for (;;) { 3627 const BinaryOperator * BO = dyn_cast<BinaryOperator>(Ex); 3628 if (!BO || !BO->isAdditiveOp()) 3629 break; 3630 3631 const Expr *RHS = BO->getRHS()->IgnoreParenCasts(); 3632 const Expr *LHS = BO->getLHS()->IgnoreParenCasts(); 3633 3634 if (isa<IntegerLiteral>(RHS)) 3635 Ex = LHS; 3636 else if (isa<IntegerLiteral>(LHS)) 3637 Ex = RHS; 3638 else 3639 break; 3640 } 3641 3642 return Ex; 3643} 3644 3645static bool isConstantSizeArrayWithMoreThanOneElement(QualType Ty, 3646 ASTContext &Context) { 3647 // Only handle constant-sized or VLAs, but not flexible members. 3648 if (const ConstantArrayType *CAT = Context.getAsConstantArrayType(Ty)) { 3649 // Only issue the FIXIT for arrays of size > 1. 3650 if (CAT->getSize().getSExtValue() <= 1) 3651 return false; 3652 } else if (!Ty->isVariableArrayType()) { 3653 return false; 3654 } 3655 return true; 3656} 3657 3658// Warn if the user has made the 'size' argument to strlcpy or strlcat 3659// be the size of the source, instead of the destination. 3660void Sema::CheckStrlcpycatArguments(const CallExpr *Call, 3661 IdentifierInfo *FnName) { 3662 3663 // Don't crash if the user has the wrong number of arguments 3664 if (Call->getNumArgs() != 3) 3665 return; 3666 3667 const Expr *SrcArg = ignoreLiteralAdditions(Call->getArg(1), Context); 3668 const Expr *SizeArg = ignoreLiteralAdditions(Call->getArg(2), Context); 3669 const Expr *CompareWithSrc = NULL; 3670 3671 // Look for 'strlcpy(dst, x, sizeof(x))' 3672 if (const Expr *Ex = getSizeOfExprArg(SizeArg)) 3673 CompareWithSrc = Ex; 3674 else { 3675 // Look for 'strlcpy(dst, x, strlen(x))' 3676 if (const CallExpr *SizeCall = dyn_cast<CallExpr>(SizeArg)) { 3677 if (SizeCall->isBuiltinCall() == Builtin::BIstrlen 3678 && SizeCall->getNumArgs() == 1) 3679 CompareWithSrc = ignoreLiteralAdditions(SizeCall->getArg(0), Context); 3680 } 3681 } 3682 3683 if (!CompareWithSrc) 3684 return; 3685 3686 // Determine if the argument to sizeof/strlen is equal to the source 3687 // argument. In principle there's all kinds of things you could do 3688 // here, for instance creating an == expression and evaluating it with 3689 // EvaluateAsBooleanCondition, but this uses a more direct technique: 3690 const DeclRefExpr *SrcArgDRE = dyn_cast<DeclRefExpr>(SrcArg); 3691 if (!SrcArgDRE) 3692 return; 3693 3694 const DeclRefExpr *CompareWithSrcDRE = dyn_cast<DeclRefExpr>(CompareWithSrc); 3695 if (!CompareWithSrcDRE || 3696 SrcArgDRE->getDecl() != CompareWithSrcDRE->getDecl()) 3697 return; 3698 3699 const Expr *OriginalSizeArg = Call->getArg(2); 3700 Diag(CompareWithSrcDRE->getLocStart(), diag::warn_strlcpycat_wrong_size) 3701 << OriginalSizeArg->getSourceRange() << FnName; 3702 3703 // Output a FIXIT hint if the destination is an array (rather than a 3704 // pointer to an array). This could be enhanced to handle some 3705 // pointers if we know the actual size, like if DstArg is 'array+2' 3706 // we could say 'sizeof(array)-2'. 3707 const Expr *DstArg = Call->getArg(0)->IgnoreParenImpCasts(); 3708 if (!isConstantSizeArrayWithMoreThanOneElement(DstArg->getType(), Context)) 3709 return; 3710 3711 SmallString<128> sizeString; 3712 llvm::raw_svector_ostream OS(sizeString); 3713 OS << "sizeof("; 3714 DstArg->printPretty(OS, 0, getPrintingPolicy()); 3715 OS << ")"; 3716 3717 Diag(OriginalSizeArg->getLocStart(), diag::note_strlcpycat_wrong_size) 3718 << FixItHint::CreateReplacement(OriginalSizeArg->getSourceRange(), 3719 OS.str()); 3720} 3721 3722/// Check if two expressions refer to the same declaration. 3723static bool referToTheSameDecl(const Expr *E1, const Expr *E2) { 3724 if (const DeclRefExpr *D1 = dyn_cast_or_null<DeclRefExpr>(E1)) 3725 if (const DeclRefExpr *D2 = dyn_cast_or_null<DeclRefExpr>(E2)) 3726 return D1->getDecl() == D2->getDecl(); 3727 return false; 3728} 3729 3730static const Expr *getStrlenExprArg(const Expr *E) { 3731 if (const CallExpr *CE = dyn_cast<CallExpr>(E)) { 3732 const FunctionDecl *FD = CE->getDirectCallee(); 3733 if (!FD || FD->getMemoryFunctionKind() != Builtin::BIstrlen) 3734 return 0; 3735 return CE->getArg(0)->IgnoreParenCasts(); 3736 } 3737 return 0; 3738} 3739 3740// Warn on anti-patterns as the 'size' argument to strncat. 3741// The correct size argument should look like following: 3742// strncat(dst, src, sizeof(dst) - strlen(dest) - 1); 3743void Sema::CheckStrncatArguments(const CallExpr *CE, 3744 IdentifierInfo *FnName) { 3745 // Don't crash if the user has the wrong number of arguments. 3746 if (CE->getNumArgs() < 3) 3747 return; 3748 const Expr *DstArg = CE->getArg(0)->IgnoreParenCasts(); 3749 const Expr *SrcArg = CE->getArg(1)->IgnoreParenCasts(); 3750 const Expr *LenArg = CE->getArg(2)->IgnoreParenCasts(); 3751 3752 // Identify common expressions, which are wrongly used as the size argument 3753 // to strncat and may lead to buffer overflows. 3754 unsigned PatternType = 0; 3755 if (const Expr *SizeOfArg = getSizeOfExprArg(LenArg)) { 3756 // - sizeof(dst) 3757 if (referToTheSameDecl(SizeOfArg, DstArg)) 3758 PatternType = 1; 3759 // - sizeof(src) 3760 else if (referToTheSameDecl(SizeOfArg, SrcArg)) 3761 PatternType = 2; 3762 } else if (const BinaryOperator *BE = dyn_cast<BinaryOperator>(LenArg)) { 3763 if (BE->getOpcode() == BO_Sub) { 3764 const Expr *L = BE->getLHS()->IgnoreParenCasts(); 3765 const Expr *R = BE->getRHS()->IgnoreParenCasts(); 3766 // - sizeof(dst) - strlen(dst) 3767 if (referToTheSameDecl(DstArg, getSizeOfExprArg(L)) && 3768 referToTheSameDecl(DstArg, getStrlenExprArg(R))) 3769 PatternType = 1; 3770 // - sizeof(src) - (anything) 3771 else if (referToTheSameDecl(SrcArg, getSizeOfExprArg(L))) 3772 PatternType = 2; 3773 } 3774 } 3775 3776 if (PatternType == 0) 3777 return; 3778 3779 // Generate the diagnostic. 3780 SourceLocation SL = LenArg->getLocStart(); 3781 SourceRange SR = LenArg->getSourceRange(); 3782 SourceManager &SM = PP.getSourceManager(); 3783 3784 // If the function is defined as a builtin macro, do not show macro expansion. 3785 if (SM.isMacroArgExpansion(SL)) { 3786 SL = SM.getSpellingLoc(SL); 3787 SR = SourceRange(SM.getSpellingLoc(SR.getBegin()), 3788 SM.getSpellingLoc(SR.getEnd())); 3789 } 3790 3791 // Check if the destination is an array (rather than a pointer to an array). 3792 QualType DstTy = DstArg->getType(); 3793 bool isKnownSizeArray = isConstantSizeArrayWithMoreThanOneElement(DstTy, 3794 Context); 3795 if (!isKnownSizeArray) { 3796 if (PatternType == 1) 3797 Diag(SL, diag::warn_strncat_wrong_size) << SR; 3798 else 3799 Diag(SL, diag::warn_strncat_src_size) << SR; 3800 return; 3801 } 3802 3803 if (PatternType == 1) 3804 Diag(SL, diag::warn_strncat_large_size) << SR; 3805 else 3806 Diag(SL, diag::warn_strncat_src_size) << SR; 3807 3808 SmallString<128> sizeString; 3809 llvm::raw_svector_ostream OS(sizeString); 3810 OS << "sizeof("; 3811 DstArg->printPretty(OS, 0, getPrintingPolicy()); 3812 OS << ") - "; 3813 OS << "strlen("; 3814 DstArg->printPretty(OS, 0, getPrintingPolicy()); 3815 OS << ") - 1"; 3816 3817 Diag(SL, diag::note_strncat_wrong_size) 3818 << FixItHint::CreateReplacement(SR, OS.str()); 3819} 3820 3821//===--- CHECK: Return Address of Stack Variable --------------------------===// 3822 3823static Expr *EvalVal(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars, 3824 Decl *ParentDecl); 3825static Expr *EvalAddr(Expr* E, SmallVectorImpl<DeclRefExpr *> &refVars, 3826 Decl *ParentDecl); 3827 3828/// CheckReturnStackAddr - Check if a return statement returns the address 3829/// of a stack variable. 3830void 3831Sema::CheckReturnStackAddr(Expr *RetValExp, QualType lhsType, 3832 SourceLocation ReturnLoc) { 3833 3834 Expr *stackE = 0; 3835 SmallVector<DeclRefExpr *, 8> refVars; 3836 3837 // Perform checking for returned stack addresses, local blocks, 3838 // label addresses or references to temporaries. 3839 if (lhsType->isPointerType() || 3840 (!getLangOpts().ObjCAutoRefCount && lhsType->isBlockPointerType())) { 3841 stackE = EvalAddr(RetValExp, refVars, /*ParentDecl=*/0); 3842 } else if (lhsType->isReferenceType()) { 3843 stackE = EvalVal(RetValExp, refVars, /*ParentDecl=*/0); 3844 } 3845 3846 if (stackE == 0) 3847 return; // Nothing suspicious was found. 3848 3849 SourceLocation diagLoc; 3850 SourceRange diagRange; 3851 if (refVars.empty()) { 3852 diagLoc = stackE->getLocStart(); 3853 diagRange = stackE->getSourceRange(); 3854 } else { 3855 // We followed through a reference variable. 'stackE' contains the 3856 // problematic expression but we will warn at the return statement pointing 3857 // at the reference variable. We will later display the "trail" of 3858 // reference variables using notes. 3859 diagLoc = refVars[0]->getLocStart(); 3860 diagRange = refVars[0]->getSourceRange(); 3861 } 3862 3863 if (DeclRefExpr *DR = dyn_cast<DeclRefExpr>(stackE)) { //address of local var. 3864 Diag(diagLoc, lhsType->isReferenceType() ? diag::warn_ret_stack_ref 3865 : diag::warn_ret_stack_addr) 3866 << DR->getDecl()->getDeclName() << diagRange; 3867 } else if (isa<BlockExpr>(stackE)) { // local block. 3868 Diag(diagLoc, diag::err_ret_local_block) << diagRange; 3869 } else if (isa<AddrLabelExpr>(stackE)) { // address of label. 3870 Diag(diagLoc, diag::warn_ret_addr_label) << diagRange; 3871 } else { // local temporary. 3872 Diag(diagLoc, lhsType->isReferenceType() ? diag::warn_ret_local_temp_ref 3873 : diag::warn_ret_local_temp_addr) 3874 << diagRange; 3875 } 3876 3877 // Display the "trail" of reference variables that we followed until we 3878 // found the problematic expression using notes. 3879 for (unsigned i = 0, e = refVars.size(); i != e; ++i) { 3880 VarDecl *VD = cast<VarDecl>(refVars[i]->getDecl()); 3881 // If this var binds to another reference var, show the range of the next 3882 // var, otherwise the var binds to the problematic expression, in which case 3883 // show the range of the expression. 3884 SourceRange range = (i < e-1) ? refVars[i+1]->getSourceRange() 3885 : stackE->getSourceRange(); 3886 Diag(VD->getLocation(), diag::note_ref_var_local_bind) 3887 << VD->getDeclName() << range; 3888 } 3889} 3890 3891/// EvalAddr - EvalAddr and EvalVal are mutually recursive functions that 3892/// check if the expression in a return statement evaluates to an address 3893/// to a location on the stack, a local block, an address of a label, or a 3894/// reference to local temporary. The recursion is used to traverse the 3895/// AST of the return expression, with recursion backtracking when we 3896/// encounter a subexpression that (1) clearly does not lead to one of the 3897/// above problematic expressions (2) is something we cannot determine leads to 3898/// a problematic expression based on such local checking. 3899/// 3900/// Both EvalAddr and EvalVal follow through reference variables to evaluate 3901/// the expression that they point to. Such variables are added to the 3902/// 'refVars' vector so that we know what the reference variable "trail" was. 3903/// 3904/// EvalAddr processes expressions that are pointers that are used as 3905/// references (and not L-values). EvalVal handles all other values. 3906/// At the base case of the recursion is a check for the above problematic 3907/// expressions. 3908/// 3909/// This implementation handles: 3910/// 3911/// * pointer-to-pointer casts 3912/// * implicit conversions from array references to pointers 3913/// * taking the address of fields 3914/// * arbitrary interplay between "&" and "*" operators 3915/// * pointer arithmetic from an address of a stack variable 3916/// * taking the address of an array element where the array is on the stack 3917static Expr *EvalAddr(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars, 3918 Decl *ParentDecl) { 3919 if (E->isTypeDependent()) 3920 return NULL; 3921 3922 // We should only be called for evaluating pointer expressions. 3923 assert((E->getType()->isAnyPointerType() || 3924 E->getType()->isBlockPointerType() || 3925 E->getType()->isObjCQualifiedIdType()) && 3926 "EvalAddr only works on pointers"); 3927 3928 E = E->IgnoreParens(); 3929 3930 // Our "symbolic interpreter" is just a dispatch off the currently 3931 // viewed AST node. We then recursively traverse the AST by calling 3932 // EvalAddr and EvalVal appropriately. 3933 switch (E->getStmtClass()) { 3934 case Stmt::DeclRefExprClass: { 3935 DeclRefExpr *DR = cast<DeclRefExpr>(E); 3936 3937 if (VarDecl *V = dyn_cast<VarDecl>(DR->getDecl())) 3938 // If this is a reference variable, follow through to the expression that 3939 // it points to. 3940 if (V->hasLocalStorage() && 3941 V->getType()->isReferenceType() && V->hasInit()) { 3942 // Add the reference variable to the "trail". 3943 refVars.push_back(DR); 3944 return EvalAddr(V->getInit(), refVars, ParentDecl); 3945 } 3946 3947 return NULL; 3948 } 3949 3950 case Stmt::UnaryOperatorClass: { 3951 // The only unary operator that make sense to handle here 3952 // is AddrOf. All others don't make sense as pointers. 3953 UnaryOperator *U = cast<UnaryOperator>(E); 3954 3955 if (U->getOpcode() == UO_AddrOf) 3956 return EvalVal(U->getSubExpr(), refVars, ParentDecl); 3957 else 3958 return NULL; 3959 } 3960 3961 case Stmt::BinaryOperatorClass: { 3962 // Handle pointer arithmetic. All other binary operators are not valid 3963 // in this context. 3964 BinaryOperator *B = cast<BinaryOperator>(E); 3965 BinaryOperatorKind op = B->getOpcode(); 3966 3967 if (op != BO_Add && op != BO_Sub) 3968 return NULL; 3969 3970 Expr *Base = B->getLHS(); 3971 3972 // Determine which argument is the real pointer base. It could be 3973 // the RHS argument instead of the LHS. 3974 if (!Base->getType()->isPointerType()) Base = B->getRHS(); 3975 3976 assert (Base->getType()->isPointerType()); 3977 return EvalAddr(Base, refVars, ParentDecl); 3978 } 3979 3980 // For conditional operators we need to see if either the LHS or RHS are 3981 // valid DeclRefExpr*s. If one of them is valid, we return it. 3982 case Stmt::ConditionalOperatorClass: { 3983 ConditionalOperator *C = cast<ConditionalOperator>(E); 3984 3985 // Handle the GNU extension for missing LHS. 3986 if (Expr *lhsExpr = C->getLHS()) { 3987 // In C++, we can have a throw-expression, which has 'void' type. 3988 if (!lhsExpr->getType()->isVoidType()) 3989 if (Expr* LHS = EvalAddr(lhsExpr, refVars, ParentDecl)) 3990 return LHS; 3991 } 3992 3993 // In C++, we can have a throw-expression, which has 'void' type. 3994 if (C->getRHS()->getType()->isVoidType()) 3995 return NULL; 3996 3997 return EvalAddr(C->getRHS(), refVars, ParentDecl); 3998 } 3999 4000 case Stmt::BlockExprClass: 4001 if (cast<BlockExpr>(E)->getBlockDecl()->hasCaptures()) 4002 return E; // local block. 4003 return NULL; 4004 4005 case Stmt::AddrLabelExprClass: 4006 return E; // address of label. 4007 4008 case Stmt::ExprWithCleanupsClass: 4009 return EvalAddr(cast<ExprWithCleanups>(E)->getSubExpr(), refVars, 4010 ParentDecl); 4011 4012 // For casts, we need to handle conversions from arrays to 4013 // pointer values, and pointer-to-pointer conversions. 4014 case Stmt::ImplicitCastExprClass: 4015 case Stmt::CStyleCastExprClass: 4016 case Stmt::CXXFunctionalCastExprClass: 4017 case Stmt::ObjCBridgedCastExprClass: 4018 case Stmt::CXXStaticCastExprClass: 4019 case Stmt::CXXDynamicCastExprClass: 4020 case Stmt::CXXConstCastExprClass: 4021 case Stmt::CXXReinterpretCastExprClass: { 4022 Expr* SubExpr = cast<CastExpr>(E)->getSubExpr(); 4023 switch (cast<CastExpr>(E)->getCastKind()) { 4024 case CK_BitCast: 4025 case CK_LValueToRValue: 4026 case CK_NoOp: 4027 case CK_BaseToDerived: 4028 case CK_DerivedToBase: 4029 case CK_UncheckedDerivedToBase: 4030 case CK_Dynamic: 4031 case CK_CPointerToObjCPointerCast: 4032 case CK_BlockPointerToObjCPointerCast: 4033 case CK_AnyPointerToBlockPointerCast: 4034 return EvalAddr(SubExpr, refVars, ParentDecl); 4035 4036 case CK_ArrayToPointerDecay: 4037 return EvalVal(SubExpr, refVars, ParentDecl); 4038 4039 default: 4040 return 0; 4041 } 4042 } 4043 4044 case Stmt::MaterializeTemporaryExprClass: 4045 if (Expr *Result = EvalAddr( 4046 cast<MaterializeTemporaryExpr>(E)->GetTemporaryExpr(), 4047 refVars, ParentDecl)) 4048 return Result; 4049 4050 return E; 4051 4052 // Everything else: we simply don't reason about them. 4053 default: 4054 return NULL; 4055 } 4056} 4057 4058 4059/// EvalVal - This function is complements EvalAddr in the mutual recursion. 4060/// See the comments for EvalAddr for more details. 4061static Expr *EvalVal(Expr *E, SmallVectorImpl<DeclRefExpr *> &refVars, 4062 Decl *ParentDecl) { 4063do { 4064 // We should only be called for evaluating non-pointer expressions, or 4065 // expressions with a pointer type that are not used as references but instead 4066 // are l-values (e.g., DeclRefExpr with a pointer type). 4067 4068 // Our "symbolic interpreter" is just a dispatch off the currently 4069 // viewed AST node. We then recursively traverse the AST by calling 4070 // EvalAddr and EvalVal appropriately. 4071 4072 E = E->IgnoreParens(); 4073 switch (E->getStmtClass()) { 4074 case Stmt::ImplicitCastExprClass: { 4075 ImplicitCastExpr *IE = cast<ImplicitCastExpr>(E); 4076 if (IE->getValueKind() == VK_LValue) { 4077 E = IE->getSubExpr(); 4078 continue; 4079 } 4080 return NULL; 4081 } 4082 4083 case Stmt::ExprWithCleanupsClass: 4084 return EvalVal(cast<ExprWithCleanups>(E)->getSubExpr(), refVars,ParentDecl); 4085 4086 case Stmt::DeclRefExprClass: { 4087 // When we hit a DeclRefExpr we are looking at code that refers to a 4088 // variable's name. If it's not a reference variable we check if it has 4089 // local storage within the function, and if so, return the expression. 4090 DeclRefExpr *DR = cast<DeclRefExpr>(E); 4091 4092 if (VarDecl *V = dyn_cast<VarDecl>(DR->getDecl())) { 4093 // Check if it refers to itself, e.g. "int& i = i;". 4094 if (V == ParentDecl) 4095 return DR; 4096 4097 if (V->hasLocalStorage()) { 4098 if (!V->getType()->isReferenceType()) 4099 return DR; 4100 4101 // Reference variable, follow through to the expression that 4102 // it points to. 4103 if (V->hasInit()) { 4104 // Add the reference variable to the "trail". 4105 refVars.push_back(DR); 4106 return EvalVal(V->getInit(), refVars, V); 4107 } 4108 } 4109 } 4110 4111 return NULL; 4112 } 4113 4114 case Stmt::UnaryOperatorClass: { 4115 // The only unary operator that make sense to handle here 4116 // is Deref. All others don't resolve to a "name." This includes 4117 // handling all sorts of rvalues passed to a unary operator. 4118 UnaryOperator *U = cast<UnaryOperator>(E); 4119 4120 if (U->getOpcode() == UO_Deref) 4121 return EvalAddr(U->getSubExpr(), refVars, ParentDecl); 4122 4123 return NULL; 4124 } 4125 4126 case Stmt::ArraySubscriptExprClass: { 4127 // Array subscripts are potential references to data on the stack. We 4128 // retrieve the DeclRefExpr* for the array variable if it indeed 4129 // has local storage. 4130 return EvalAddr(cast<ArraySubscriptExpr>(E)->getBase(), refVars,ParentDecl); 4131 } 4132 4133 case Stmt::ConditionalOperatorClass: { 4134 // For conditional operators we need to see if either the LHS or RHS are 4135 // non-NULL Expr's. If one is non-NULL, we return it. 4136 ConditionalOperator *C = cast<ConditionalOperator>(E); 4137 4138 // Handle the GNU extension for missing LHS. 4139 if (Expr *lhsExpr = C->getLHS()) 4140 if (Expr *LHS = EvalVal(lhsExpr, refVars, ParentDecl)) 4141 return LHS; 4142 4143 return EvalVal(C->getRHS(), refVars, ParentDecl); 4144 } 4145 4146 // Accesses to members are potential references to data on the stack. 4147 case Stmt::MemberExprClass: { 4148 MemberExpr *M = cast<MemberExpr>(E); 4149 4150 // Check for indirect access. We only want direct field accesses. 4151 if (M->isArrow()) 4152 return NULL; 4153 4154 // Check whether the member type is itself a reference, in which case 4155 // we're not going to refer to the member, but to what the member refers to. 4156 if (M->getMemberDecl()->getType()->isReferenceType()) 4157 return NULL; 4158 4159 return EvalVal(M->getBase(), refVars, ParentDecl); 4160 } 4161 4162 case Stmt::MaterializeTemporaryExprClass: 4163 if (Expr *Result = EvalVal( 4164 cast<MaterializeTemporaryExpr>(E)->GetTemporaryExpr(), 4165 refVars, ParentDecl)) 4166 return Result; 4167 4168 return E; 4169 4170 default: 4171 // Check that we don't return or take the address of a reference to a 4172 // temporary. This is only useful in C++. 4173 if (!E->isTypeDependent() && E->isRValue()) 4174 return E; 4175 4176 // Everything else: we simply don't reason about them. 4177 return NULL; 4178 } 4179} while (true); 4180} 4181 4182//===--- CHECK: Floating-Point comparisons (-Wfloat-equal) ---------------===// 4183 4184/// Check for comparisons of floating point operands using != and ==. 4185/// Issue a warning if these are no self-comparisons, as they are not likely 4186/// to do what the programmer intended. 4187void Sema::CheckFloatComparison(SourceLocation Loc, Expr* LHS, Expr *RHS) { 4188 Expr* LeftExprSansParen = LHS->IgnoreParenImpCasts(); 4189 Expr* RightExprSansParen = RHS->IgnoreParenImpCasts(); 4190 4191 // Special case: check for x == x (which is OK). 4192 // Do not emit warnings for such cases. 4193 if (DeclRefExpr* DRL = dyn_cast<DeclRefExpr>(LeftExprSansParen)) 4194 if (DeclRefExpr* DRR = dyn_cast<DeclRefExpr>(RightExprSansParen)) 4195 if (DRL->getDecl() == DRR->getDecl()) 4196 return; 4197 4198 4199 // Special case: check for comparisons against literals that can be exactly 4200 // represented by APFloat. In such cases, do not emit a warning. This 4201 // is a heuristic: often comparison against such literals are used to 4202 // detect if a value in a variable has not changed. This clearly can 4203 // lead to false negatives. 4204 if (FloatingLiteral* FLL = dyn_cast<FloatingLiteral>(LeftExprSansParen)) { 4205 if (FLL->isExact()) 4206 return; 4207 } else 4208 if (FloatingLiteral* FLR = dyn_cast<FloatingLiteral>(RightExprSansParen)) 4209 if (FLR->isExact()) 4210 return; 4211 4212 // Check for comparisons with builtin types. 4213 if (CallExpr* CL = dyn_cast<CallExpr>(LeftExprSansParen)) 4214 if (CL->isBuiltinCall()) 4215 return; 4216 4217 if (CallExpr* CR = dyn_cast<CallExpr>(RightExprSansParen)) 4218 if (CR->isBuiltinCall()) 4219 return; 4220 4221 // Emit the diagnostic. 4222 Diag(Loc, diag::warn_floatingpoint_eq) 4223 << LHS->getSourceRange() << RHS->getSourceRange(); 4224} 4225 4226//===--- CHECK: Integer mixed-sign comparisons (-Wsign-compare) --------===// 4227//===--- CHECK: Lossy implicit conversions (-Wconversion) --------------===// 4228 4229namespace { 4230 4231/// Structure recording the 'active' range of an integer-valued 4232/// expression. 4233struct IntRange { 4234 /// The number of bits active in the int. 4235 unsigned Width; 4236 4237 /// True if the int is known not to have negative values. 4238 bool NonNegative; 4239 4240 IntRange(unsigned Width, bool NonNegative) 4241 : Width(Width), NonNegative(NonNegative) 4242 {} 4243 4244 /// Returns the range of the bool type. 4245 static IntRange forBoolType() { 4246 return IntRange(1, true); 4247 } 4248 4249 /// Returns the range of an opaque value of the given integral type. 4250 static IntRange forValueOfType(ASTContext &C, QualType T) { 4251 return forValueOfCanonicalType(C, 4252 T->getCanonicalTypeInternal().getTypePtr()); 4253 } 4254 4255 /// Returns the range of an opaque value of a canonical integral type. 4256 static IntRange forValueOfCanonicalType(ASTContext &C, const Type *T) { 4257 assert(T->isCanonicalUnqualified()); 4258 4259 if (const VectorType *VT = dyn_cast<VectorType>(T)) 4260 T = VT->getElementType().getTypePtr(); 4261 if (const ComplexType *CT = dyn_cast<ComplexType>(T)) 4262 T = CT->getElementType().getTypePtr(); 4263 4264 // For enum types, use the known bit width of the enumerators. 4265 if (const EnumType *ET = dyn_cast<EnumType>(T)) { 4266 EnumDecl *Enum = ET->getDecl(); 4267 if (!Enum->isCompleteDefinition()) 4268 return IntRange(C.getIntWidth(QualType(T, 0)), false); 4269 4270 unsigned NumPositive = Enum->getNumPositiveBits(); 4271 unsigned NumNegative = Enum->getNumNegativeBits(); 4272 4273 if (NumNegative == 0) 4274 return IntRange(NumPositive, true/*NonNegative*/); 4275 else 4276 return IntRange(std::max(NumPositive + 1, NumNegative), 4277 false/*NonNegative*/); 4278 } 4279 4280 const BuiltinType *BT = cast<BuiltinType>(T); 4281 assert(BT->isInteger()); 4282 4283 return IntRange(C.getIntWidth(QualType(T, 0)), BT->isUnsignedInteger()); 4284 } 4285 4286 /// Returns the "target" range of a canonical integral type, i.e. 4287 /// the range of values expressible in the type. 4288 /// 4289 /// This matches forValueOfCanonicalType except that enums have the 4290 /// full range of their type, not the range of their enumerators. 4291 static IntRange forTargetOfCanonicalType(ASTContext &C, const Type *T) { 4292 assert(T->isCanonicalUnqualified()); 4293 4294 if (const VectorType *VT = dyn_cast<VectorType>(T)) 4295 T = VT->getElementType().getTypePtr(); 4296 if (const ComplexType *CT = dyn_cast<ComplexType>(T)) 4297 T = CT->getElementType().getTypePtr(); 4298 if (const EnumType *ET = dyn_cast<EnumType>(T)) 4299 T = C.getCanonicalType(ET->getDecl()->getIntegerType()).getTypePtr(); 4300 4301 const BuiltinType *BT = cast<BuiltinType>(T); 4302 assert(BT->isInteger()); 4303 4304 return IntRange(C.getIntWidth(QualType(T, 0)), BT->isUnsignedInteger()); 4305 } 4306 4307 /// Returns the supremum of two ranges: i.e. their conservative merge. 4308 static IntRange join(IntRange L, IntRange R) { 4309 return IntRange(std::max(L.Width, R.Width), 4310 L.NonNegative && R.NonNegative); 4311 } 4312 4313 /// Returns the infinum of two ranges: i.e. their aggressive merge. 4314 static IntRange meet(IntRange L, IntRange R) { 4315 return IntRange(std::min(L.Width, R.Width), 4316 L.NonNegative || R.NonNegative); 4317 } 4318}; 4319 4320static IntRange GetValueRange(ASTContext &C, llvm::APSInt &value, 4321 unsigned MaxWidth) { 4322 if (value.isSigned() && value.isNegative()) 4323 return IntRange(value.getMinSignedBits(), false); 4324 4325 if (value.getBitWidth() > MaxWidth) 4326 value = value.trunc(MaxWidth); 4327 4328 // isNonNegative() just checks the sign bit without considering 4329 // signedness. 4330 return IntRange(value.getActiveBits(), true); 4331} 4332 4333static IntRange GetValueRange(ASTContext &C, APValue &result, QualType Ty, 4334 unsigned MaxWidth) { 4335 if (result.isInt()) 4336 return GetValueRange(C, result.getInt(), MaxWidth); 4337 4338 if (result.isVector()) { 4339 IntRange R = GetValueRange(C, result.getVectorElt(0), Ty, MaxWidth); 4340 for (unsigned i = 1, e = result.getVectorLength(); i != e; ++i) { 4341 IntRange El = GetValueRange(C, result.getVectorElt(i), Ty, MaxWidth); 4342 R = IntRange::join(R, El); 4343 } 4344 return R; 4345 } 4346 4347 if (result.isComplexInt()) { 4348 IntRange R = GetValueRange(C, result.getComplexIntReal(), MaxWidth); 4349 IntRange I = GetValueRange(C, result.getComplexIntImag(), MaxWidth); 4350 return IntRange::join(R, I); 4351 } 4352 4353 // This can happen with lossless casts to intptr_t of "based" lvalues. 4354 // Assume it might use arbitrary bits. 4355 // FIXME: The only reason we need to pass the type in here is to get 4356 // the sign right on this one case. It would be nice if APValue 4357 // preserved this. 4358 assert(result.isLValue() || result.isAddrLabelDiff()); 4359 return IntRange(MaxWidth, Ty->isUnsignedIntegerOrEnumerationType()); 4360} 4361 4362static QualType GetExprType(Expr *E) { 4363 QualType Ty = E->getType(); 4364 if (const AtomicType *AtomicRHS = Ty->getAs<AtomicType>()) 4365 Ty = AtomicRHS->getValueType(); 4366 return Ty; 4367} 4368 4369/// Pseudo-evaluate the given integer expression, estimating the 4370/// range of values it might take. 4371/// 4372/// \param MaxWidth - the width to which the value will be truncated 4373static IntRange GetExprRange(ASTContext &C, Expr *E, unsigned MaxWidth) { 4374 E = E->IgnoreParens(); 4375 4376 // Try a full evaluation first. 4377 Expr::EvalResult result; 4378 if (E->EvaluateAsRValue(result, C)) 4379 return GetValueRange(C, result.Val, GetExprType(E), MaxWidth); 4380 4381 // I think we only want to look through implicit casts here; if the 4382 // user has an explicit widening cast, we should treat the value as 4383 // being of the new, wider type. 4384 if (ImplicitCastExpr *CE = dyn_cast<ImplicitCastExpr>(E)) { 4385 if (CE->getCastKind() == CK_NoOp || CE->getCastKind() == CK_LValueToRValue) 4386 return GetExprRange(C, CE->getSubExpr(), MaxWidth); 4387 4388 IntRange OutputTypeRange = IntRange::forValueOfType(C, GetExprType(CE)); 4389 4390 bool isIntegerCast = (CE->getCastKind() == CK_IntegralCast); 4391 4392 // Assume that non-integer casts can span the full range of the type. 4393 if (!isIntegerCast) 4394 return OutputTypeRange; 4395 4396 IntRange SubRange 4397 = GetExprRange(C, CE->getSubExpr(), 4398 std::min(MaxWidth, OutputTypeRange.Width)); 4399 4400 // Bail out if the subexpr's range is as wide as the cast type. 4401 if (SubRange.Width >= OutputTypeRange.Width) 4402 return OutputTypeRange; 4403 4404 // Otherwise, we take the smaller width, and we're non-negative if 4405 // either the output type or the subexpr is. 4406 return IntRange(SubRange.Width, 4407 SubRange.NonNegative || OutputTypeRange.NonNegative); 4408 } 4409 4410 if (ConditionalOperator *CO = dyn_cast<ConditionalOperator>(E)) { 4411 // If we can fold the condition, just take that operand. 4412 bool CondResult; 4413 if (CO->getCond()->EvaluateAsBooleanCondition(CondResult, C)) 4414 return GetExprRange(C, CondResult ? CO->getTrueExpr() 4415 : CO->getFalseExpr(), 4416 MaxWidth); 4417 4418 // Otherwise, conservatively merge. 4419 IntRange L = GetExprRange(C, CO->getTrueExpr(), MaxWidth); 4420 IntRange R = GetExprRange(C, CO->getFalseExpr(), MaxWidth); 4421 return IntRange::join(L, R); 4422 } 4423 4424 if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) { 4425 switch (BO->getOpcode()) { 4426 4427 // Boolean-valued operations are single-bit and positive. 4428 case BO_LAnd: 4429 case BO_LOr: 4430 case BO_LT: 4431 case BO_GT: 4432 case BO_LE: 4433 case BO_GE: 4434 case BO_EQ: 4435 case BO_NE: 4436 return IntRange::forBoolType(); 4437 4438 // The type of the assignments is the type of the LHS, so the RHS 4439 // is not necessarily the same type. 4440 case BO_MulAssign: 4441 case BO_DivAssign: 4442 case BO_RemAssign: 4443 case BO_AddAssign: 4444 case BO_SubAssign: 4445 case BO_XorAssign: 4446 case BO_OrAssign: 4447 // TODO: bitfields? 4448 return IntRange::forValueOfType(C, GetExprType(E)); 4449 4450 // Simple assignments just pass through the RHS, which will have 4451 // been coerced to the LHS type. 4452 case BO_Assign: 4453 // TODO: bitfields? 4454 return GetExprRange(C, BO->getRHS(), MaxWidth); 4455 4456 // Operations with opaque sources are black-listed. 4457 case BO_PtrMemD: 4458 case BO_PtrMemI: 4459 return IntRange::forValueOfType(C, GetExprType(E)); 4460 4461 // Bitwise-and uses the *infinum* of the two source ranges. 4462 case BO_And: 4463 case BO_AndAssign: 4464 return IntRange::meet(GetExprRange(C, BO->getLHS(), MaxWidth), 4465 GetExprRange(C, BO->getRHS(), MaxWidth)); 4466 4467 // Left shift gets black-listed based on a judgement call. 4468 case BO_Shl: 4469 // ...except that we want to treat '1 << (blah)' as logically 4470 // positive. It's an important idiom. 4471 if (IntegerLiteral *I 4472 = dyn_cast<IntegerLiteral>(BO->getLHS()->IgnoreParenCasts())) { 4473 if (I->getValue() == 1) { 4474 IntRange R = IntRange::forValueOfType(C, GetExprType(E)); 4475 return IntRange(R.Width, /*NonNegative*/ true); 4476 } 4477 } 4478 // fallthrough 4479 4480 case BO_ShlAssign: 4481 return IntRange::forValueOfType(C, GetExprType(E)); 4482 4483 // Right shift by a constant can narrow its left argument. 4484 case BO_Shr: 4485 case BO_ShrAssign: { 4486 IntRange L = GetExprRange(C, BO->getLHS(), MaxWidth); 4487 4488 // If the shift amount is a positive constant, drop the width by 4489 // that much. 4490 llvm::APSInt shift; 4491 if (BO->getRHS()->isIntegerConstantExpr(shift, C) && 4492 shift.isNonNegative()) { 4493 unsigned zext = shift.getZExtValue(); 4494 if (zext >= L.Width) 4495 L.Width = (L.NonNegative ? 0 : 1); 4496 else 4497 L.Width -= zext; 4498 } 4499 4500 return L; 4501 } 4502 4503 // Comma acts as its right operand. 4504 case BO_Comma: 4505 return GetExprRange(C, BO->getRHS(), MaxWidth); 4506 4507 // Black-list pointer subtractions. 4508 case BO_Sub: 4509 if (BO->getLHS()->getType()->isPointerType()) 4510 return IntRange::forValueOfType(C, GetExprType(E)); 4511 break; 4512 4513 // The width of a division result is mostly determined by the size 4514 // of the LHS. 4515 case BO_Div: { 4516 // Don't 'pre-truncate' the operands. 4517 unsigned opWidth = C.getIntWidth(GetExprType(E)); 4518 IntRange L = GetExprRange(C, BO->getLHS(), opWidth); 4519 4520 // If the divisor is constant, use that. 4521 llvm::APSInt divisor; 4522 if (BO->getRHS()->isIntegerConstantExpr(divisor, C)) { 4523 unsigned log2 = divisor.logBase2(); // floor(log_2(divisor)) 4524 if (log2 >= L.Width) 4525 L.Width = (L.NonNegative ? 0 : 1); 4526 else 4527 L.Width = std::min(L.Width - log2, MaxWidth); 4528 return L; 4529 } 4530 4531 // Otherwise, just use the LHS's width. 4532 IntRange R = GetExprRange(C, BO->getRHS(), opWidth); 4533 return IntRange(L.Width, L.NonNegative && R.NonNegative); 4534 } 4535 4536 // The result of a remainder can't be larger than the result of 4537 // either side. 4538 case BO_Rem: { 4539 // Don't 'pre-truncate' the operands. 4540 unsigned opWidth = C.getIntWidth(GetExprType(E)); 4541 IntRange L = GetExprRange(C, BO->getLHS(), opWidth); 4542 IntRange R = GetExprRange(C, BO->getRHS(), opWidth); 4543 4544 IntRange meet = IntRange::meet(L, R); 4545 meet.Width = std::min(meet.Width, MaxWidth); 4546 return meet; 4547 } 4548 4549 // The default behavior is okay for these. 4550 case BO_Mul: 4551 case BO_Add: 4552 case BO_Xor: 4553 case BO_Or: 4554 break; 4555 } 4556 4557 // The default case is to treat the operation as if it were closed 4558 // on the narrowest type that encompasses both operands. 4559 IntRange L = GetExprRange(C, BO->getLHS(), MaxWidth); 4560 IntRange R = GetExprRange(C, BO->getRHS(), MaxWidth); 4561 return IntRange::join(L, R); 4562 } 4563 4564 if (UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) { 4565 switch (UO->getOpcode()) { 4566 // Boolean-valued operations are white-listed. 4567 case UO_LNot: 4568 return IntRange::forBoolType(); 4569 4570 // Operations with opaque sources are black-listed. 4571 case UO_Deref: 4572 case UO_AddrOf: // should be impossible 4573 return IntRange::forValueOfType(C, GetExprType(E)); 4574 4575 default: 4576 return GetExprRange(C, UO->getSubExpr(), MaxWidth); 4577 } 4578 } 4579 4580 if (FieldDecl *BitField = E->getSourceBitField()) 4581 return IntRange(BitField->getBitWidthValue(C), 4582 BitField->getType()->isUnsignedIntegerOrEnumerationType()); 4583 4584 return IntRange::forValueOfType(C, GetExprType(E)); 4585} 4586 4587static IntRange GetExprRange(ASTContext &C, Expr *E) { 4588 return GetExprRange(C, E, C.getIntWidth(GetExprType(E))); 4589} 4590 4591/// Checks whether the given value, which currently has the given 4592/// source semantics, has the same value when coerced through the 4593/// target semantics. 4594static bool IsSameFloatAfterCast(const llvm::APFloat &value, 4595 const llvm::fltSemantics &Src, 4596 const llvm::fltSemantics &Tgt) { 4597 llvm::APFloat truncated = value; 4598 4599 bool ignored; 4600 truncated.convert(Src, llvm::APFloat::rmNearestTiesToEven, &ignored); 4601 truncated.convert(Tgt, llvm::APFloat::rmNearestTiesToEven, &ignored); 4602 4603 return truncated.bitwiseIsEqual(value); 4604} 4605 4606/// Checks whether the given value, which currently has the given 4607/// source semantics, has the same value when coerced through the 4608/// target semantics. 4609/// 4610/// The value might be a vector of floats (or a complex number). 4611static bool IsSameFloatAfterCast(const APValue &value, 4612 const llvm::fltSemantics &Src, 4613 const llvm::fltSemantics &Tgt) { 4614 if (value.isFloat()) 4615 return IsSameFloatAfterCast(value.getFloat(), Src, Tgt); 4616 4617 if (value.isVector()) { 4618 for (unsigned i = 0, e = value.getVectorLength(); i != e; ++i) 4619 if (!IsSameFloatAfterCast(value.getVectorElt(i), Src, Tgt)) 4620 return false; 4621 return true; 4622 } 4623 4624 assert(value.isComplexFloat()); 4625 return (IsSameFloatAfterCast(value.getComplexFloatReal(), Src, Tgt) && 4626 IsSameFloatAfterCast(value.getComplexFloatImag(), Src, Tgt)); 4627} 4628 4629static void AnalyzeImplicitConversions(Sema &S, Expr *E, SourceLocation CC); 4630 4631static bool IsZero(Sema &S, Expr *E) { 4632 // Suppress cases where we are comparing against an enum constant. 4633 if (const DeclRefExpr *DR = 4634 dyn_cast<DeclRefExpr>(E->IgnoreParenImpCasts())) 4635 if (isa<EnumConstantDecl>(DR->getDecl())) 4636 return false; 4637 4638 // Suppress cases where the '0' value is expanded from a macro. 4639 if (E->getLocStart().isMacroID()) 4640 return false; 4641 4642 llvm::APSInt Value; 4643 return E->isIntegerConstantExpr(Value, S.Context) && Value == 0; 4644} 4645 4646static bool HasEnumType(Expr *E) { 4647 // Strip off implicit integral promotions. 4648 while (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) { 4649 if (ICE->getCastKind() != CK_IntegralCast && 4650 ICE->getCastKind() != CK_NoOp) 4651 break; 4652 E = ICE->getSubExpr(); 4653 } 4654 4655 return E->getType()->isEnumeralType(); 4656} 4657 4658static void CheckTrivialUnsignedComparison(Sema &S, BinaryOperator *E) { 4659 BinaryOperatorKind op = E->getOpcode(); 4660 if (E->isValueDependent()) 4661 return; 4662 4663 if (op == BO_LT && IsZero(S, E->getRHS())) { 4664 S.Diag(E->getOperatorLoc(), diag::warn_lunsigned_always_true_comparison) 4665 << "< 0" << "false" << HasEnumType(E->getLHS()) 4666 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); 4667 } else if (op == BO_GE && IsZero(S, E->getRHS())) { 4668 S.Diag(E->getOperatorLoc(), diag::warn_lunsigned_always_true_comparison) 4669 << ">= 0" << "true" << HasEnumType(E->getLHS()) 4670 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); 4671 } else if (op == BO_GT && IsZero(S, E->getLHS())) { 4672 S.Diag(E->getOperatorLoc(), diag::warn_runsigned_always_true_comparison) 4673 << "0 >" << "false" << HasEnumType(E->getRHS()) 4674 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); 4675 } else if (op == BO_LE && IsZero(S, E->getLHS())) { 4676 S.Diag(E->getOperatorLoc(), diag::warn_runsigned_always_true_comparison) 4677 << "0 <=" << "true" << HasEnumType(E->getRHS()) 4678 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); 4679 } 4680} 4681 4682static void DiagnoseOutOfRangeComparison(Sema &S, BinaryOperator *E, 4683 Expr *Constant, Expr *Other, 4684 llvm::APSInt Value, 4685 bool RhsConstant) { 4686 // 0 values are handled later by CheckTrivialUnsignedComparison(). 4687 if (Value == 0) 4688 return; 4689 4690 BinaryOperatorKind op = E->getOpcode(); 4691 QualType OtherT = Other->getType(); 4692 QualType ConstantT = Constant->getType(); 4693 QualType CommonT = E->getLHS()->getType(); 4694 if (S.Context.hasSameUnqualifiedType(OtherT, ConstantT)) 4695 return; 4696 assert((OtherT->isIntegerType() && ConstantT->isIntegerType()) 4697 && "comparison with non-integer type"); 4698 4699 bool ConstantSigned = ConstantT->isSignedIntegerType(); 4700 bool CommonSigned = CommonT->isSignedIntegerType(); 4701 4702 bool EqualityOnly = false; 4703 4704 // TODO: Investigate using GetExprRange() to get tighter bounds on 4705 // on the bit ranges. 4706 IntRange OtherRange = IntRange::forValueOfType(S.Context, OtherT); 4707 unsigned OtherWidth = OtherRange.Width; 4708 4709 if (CommonSigned) { 4710 // The common type is signed, therefore no signed to unsigned conversion. 4711 if (!OtherRange.NonNegative) { 4712 // Check that the constant is representable in type OtherT. 4713 if (ConstantSigned) { 4714 if (OtherWidth >= Value.getMinSignedBits()) 4715 return; 4716 } else { // !ConstantSigned 4717 if (OtherWidth >= Value.getActiveBits() + 1) 4718 return; 4719 } 4720 } else { // !OtherSigned 4721 // Check that the constant is representable in type OtherT. 4722 // Negative values are out of range. 4723 if (ConstantSigned) { 4724 if (Value.isNonNegative() && OtherWidth >= Value.getActiveBits()) 4725 return; 4726 } else { // !ConstantSigned 4727 if (OtherWidth >= Value.getActiveBits()) 4728 return; 4729 } 4730 } 4731 } else { // !CommonSigned 4732 if (OtherRange.NonNegative) { 4733 if (OtherWidth >= Value.getActiveBits()) 4734 return; 4735 } else if (!OtherRange.NonNegative && !ConstantSigned) { 4736 // Check to see if the constant is representable in OtherT. 4737 if (OtherWidth > Value.getActiveBits()) 4738 return; 4739 // Check to see if the constant is equivalent to a negative value 4740 // cast to CommonT. 4741 if (S.Context.getIntWidth(ConstantT) == S.Context.getIntWidth(CommonT) && 4742 Value.isNegative() && Value.getMinSignedBits() <= OtherWidth) 4743 return; 4744 // The constant value rests between values that OtherT can represent after 4745 // conversion. Relational comparison still works, but equality 4746 // comparisons will be tautological. 4747 EqualityOnly = true; 4748 } else { // OtherSigned && ConstantSigned 4749 assert(0 && "Two signed types converted to unsigned types."); 4750 } 4751 } 4752 4753 bool PositiveConstant = !ConstantSigned || Value.isNonNegative(); 4754 4755 bool IsTrue = true; 4756 if (op == BO_EQ || op == BO_NE) { 4757 IsTrue = op == BO_NE; 4758 } else if (EqualityOnly) { 4759 return; 4760 } else if (RhsConstant) { 4761 if (op == BO_GT || op == BO_GE) 4762 IsTrue = !PositiveConstant; 4763 else // op == BO_LT || op == BO_LE 4764 IsTrue = PositiveConstant; 4765 } else { 4766 if (op == BO_LT || op == BO_LE) 4767 IsTrue = !PositiveConstant; 4768 else // op == BO_GT || op == BO_GE 4769 IsTrue = PositiveConstant; 4770 } 4771 4772 // If this is a comparison to an enum constant, include that 4773 // constant in the diagnostic. 4774 const EnumConstantDecl *ED = 0; 4775 if (const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(Constant)) 4776 ED = dyn_cast<EnumConstantDecl>(DR->getDecl()); 4777 4778 SmallString<64> PrettySourceValue; 4779 llvm::raw_svector_ostream OS(PrettySourceValue); 4780 if (ED) 4781 OS << '\'' << *ED << "' (" << Value << ")"; 4782 else 4783 OS << Value; 4784 4785 S.Diag(E->getOperatorLoc(), diag::warn_out_of_range_compare) 4786 << OS.str() << OtherT << IsTrue 4787 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); 4788} 4789 4790/// Analyze the operands of the given comparison. Implements the 4791/// fallback case from AnalyzeComparison. 4792static void AnalyzeImpConvsInComparison(Sema &S, BinaryOperator *E) { 4793 AnalyzeImplicitConversions(S, E->getLHS(), E->getOperatorLoc()); 4794 AnalyzeImplicitConversions(S, E->getRHS(), E->getOperatorLoc()); 4795} 4796 4797/// \brief Implements -Wsign-compare. 4798/// 4799/// \param E the binary operator to check for warnings 4800static void AnalyzeComparison(Sema &S, BinaryOperator *E) { 4801 // The type the comparison is being performed in. 4802 QualType T = E->getLHS()->getType(); 4803 assert(S.Context.hasSameUnqualifiedType(T, E->getRHS()->getType()) 4804 && "comparison with mismatched types"); 4805 if (E->isValueDependent()) 4806 return AnalyzeImpConvsInComparison(S, E); 4807 4808 Expr *LHS = E->getLHS()->IgnoreParenImpCasts(); 4809 Expr *RHS = E->getRHS()->IgnoreParenImpCasts(); 4810 4811 bool IsComparisonConstant = false; 4812 4813 // Check whether an integer constant comparison results in a value 4814 // of 'true' or 'false'. 4815 if (T->isIntegralType(S.Context)) { 4816 llvm::APSInt RHSValue; 4817 bool IsRHSIntegralLiteral = 4818 RHS->isIntegerConstantExpr(RHSValue, S.Context); 4819 llvm::APSInt LHSValue; 4820 bool IsLHSIntegralLiteral = 4821 LHS->isIntegerConstantExpr(LHSValue, S.Context); 4822 if (IsRHSIntegralLiteral && !IsLHSIntegralLiteral) 4823 DiagnoseOutOfRangeComparison(S, E, RHS, LHS, RHSValue, true); 4824 else if (!IsRHSIntegralLiteral && IsLHSIntegralLiteral) 4825 DiagnoseOutOfRangeComparison(S, E, LHS, RHS, LHSValue, false); 4826 else 4827 IsComparisonConstant = 4828 (IsRHSIntegralLiteral && IsLHSIntegralLiteral); 4829 } else if (!T->hasUnsignedIntegerRepresentation()) 4830 IsComparisonConstant = E->isIntegerConstantExpr(S.Context); 4831 4832 // We don't do anything special if this isn't an unsigned integral 4833 // comparison: we're only interested in integral comparisons, and 4834 // signed comparisons only happen in cases we don't care to warn about. 4835 // 4836 // We also don't care about value-dependent expressions or expressions 4837 // whose result is a constant. 4838 if (!T->hasUnsignedIntegerRepresentation() || IsComparisonConstant) 4839 return AnalyzeImpConvsInComparison(S, E); 4840 4841 // Check to see if one of the (unmodified) operands is of different 4842 // signedness. 4843 Expr *signedOperand, *unsignedOperand; 4844 if (LHS->getType()->hasSignedIntegerRepresentation()) { 4845 assert(!RHS->getType()->hasSignedIntegerRepresentation() && 4846 "unsigned comparison between two signed integer expressions?"); 4847 signedOperand = LHS; 4848 unsignedOperand = RHS; 4849 } else if (RHS->getType()->hasSignedIntegerRepresentation()) { 4850 signedOperand = RHS; 4851 unsignedOperand = LHS; 4852 } else { 4853 CheckTrivialUnsignedComparison(S, E); 4854 return AnalyzeImpConvsInComparison(S, E); 4855 } 4856 4857 // Otherwise, calculate the effective range of the signed operand. 4858 IntRange signedRange = GetExprRange(S.Context, signedOperand); 4859 4860 // Go ahead and analyze implicit conversions in the operands. Note 4861 // that we skip the implicit conversions on both sides. 4862 AnalyzeImplicitConversions(S, LHS, E->getOperatorLoc()); 4863 AnalyzeImplicitConversions(S, RHS, E->getOperatorLoc()); 4864 4865 // If the signed range is non-negative, -Wsign-compare won't fire, 4866 // but we should still check for comparisons which are always true 4867 // or false. 4868 if (signedRange.NonNegative) 4869 return CheckTrivialUnsignedComparison(S, E); 4870 4871 // For (in)equality comparisons, if the unsigned operand is a 4872 // constant which cannot collide with a overflowed signed operand, 4873 // then reinterpreting the signed operand as unsigned will not 4874 // change the result of the comparison. 4875 if (E->isEqualityOp()) { 4876 unsigned comparisonWidth = S.Context.getIntWidth(T); 4877 IntRange unsignedRange = GetExprRange(S.Context, unsignedOperand); 4878 4879 // We should never be unable to prove that the unsigned operand is 4880 // non-negative. 4881 assert(unsignedRange.NonNegative && "unsigned range includes negative?"); 4882 4883 if (unsignedRange.Width < comparisonWidth) 4884 return; 4885 } 4886 4887 S.DiagRuntimeBehavior(E->getOperatorLoc(), E, 4888 S.PDiag(diag::warn_mixed_sign_comparison) 4889 << LHS->getType() << RHS->getType() 4890 << LHS->getSourceRange() << RHS->getSourceRange()); 4891} 4892 4893/// Analyzes an attempt to assign the given value to a bitfield. 4894/// 4895/// Returns true if there was something fishy about the attempt. 4896static bool AnalyzeBitFieldAssignment(Sema &S, FieldDecl *Bitfield, Expr *Init, 4897 SourceLocation InitLoc) { 4898 assert(Bitfield->isBitField()); 4899 if (Bitfield->isInvalidDecl()) 4900 return false; 4901 4902 // White-list bool bitfields. 4903 if (Bitfield->getType()->isBooleanType()) 4904 return false; 4905 4906 // Ignore value- or type-dependent expressions. 4907 if (Bitfield->getBitWidth()->isValueDependent() || 4908 Bitfield->getBitWidth()->isTypeDependent() || 4909 Init->isValueDependent() || 4910 Init->isTypeDependent()) 4911 return false; 4912 4913 Expr *OriginalInit = Init->IgnoreParenImpCasts(); 4914 4915 llvm::APSInt Value; 4916 if (!OriginalInit->EvaluateAsInt(Value, S.Context, Expr::SE_AllowSideEffects)) 4917 return false; 4918 4919 unsigned OriginalWidth = Value.getBitWidth(); 4920 unsigned FieldWidth = Bitfield->getBitWidthValue(S.Context); 4921 4922 if (OriginalWidth <= FieldWidth) 4923 return false; 4924 4925 // Compute the value which the bitfield will contain. 4926 llvm::APSInt TruncatedValue = Value.trunc(FieldWidth); 4927 TruncatedValue.setIsSigned(Bitfield->getType()->isSignedIntegerType()); 4928 4929 // Check whether the stored value is equal to the original value. 4930 TruncatedValue = TruncatedValue.extend(OriginalWidth); 4931 if (llvm::APSInt::isSameValue(Value, TruncatedValue)) 4932 return false; 4933 4934 // Special-case bitfields of width 1: booleans are naturally 0/1, and 4935 // therefore don't strictly fit into a signed bitfield of width 1. 4936 if (FieldWidth == 1 && Value == 1) 4937 return false; 4938 4939 std::string PrettyValue = Value.toString(10); 4940 std::string PrettyTrunc = TruncatedValue.toString(10); 4941 4942 S.Diag(InitLoc, diag::warn_impcast_bitfield_precision_constant) 4943 << PrettyValue << PrettyTrunc << OriginalInit->getType() 4944 << Init->getSourceRange(); 4945 4946 return true; 4947} 4948 4949/// Analyze the given simple or compound assignment for warning-worthy 4950/// operations. 4951static void AnalyzeAssignment(Sema &S, BinaryOperator *E) { 4952 // Just recurse on the LHS. 4953 AnalyzeImplicitConversions(S, E->getLHS(), E->getOperatorLoc()); 4954 4955 // We want to recurse on the RHS as normal unless we're assigning to 4956 // a bitfield. 4957 if (FieldDecl *Bitfield = E->getLHS()->getSourceBitField()) { 4958 if (AnalyzeBitFieldAssignment(S, Bitfield, E->getRHS(), 4959 E->getOperatorLoc())) { 4960 // Recurse, ignoring any implicit conversions on the RHS. 4961 return AnalyzeImplicitConversions(S, E->getRHS()->IgnoreParenImpCasts(), 4962 E->getOperatorLoc()); 4963 } 4964 } 4965 4966 AnalyzeImplicitConversions(S, E->getRHS(), E->getOperatorLoc()); 4967} 4968 4969/// Diagnose an implicit cast; purely a helper for CheckImplicitConversion. 4970static void DiagnoseImpCast(Sema &S, Expr *E, QualType SourceType, QualType T, 4971 SourceLocation CContext, unsigned diag, 4972 bool pruneControlFlow = false) { 4973 if (pruneControlFlow) { 4974 S.DiagRuntimeBehavior(E->getExprLoc(), E, 4975 S.PDiag(diag) 4976 << SourceType << T << E->getSourceRange() 4977 << SourceRange(CContext)); 4978 return; 4979 } 4980 S.Diag(E->getExprLoc(), diag) 4981 << SourceType << T << E->getSourceRange() << SourceRange(CContext); 4982} 4983 4984/// Diagnose an implicit cast; purely a helper for CheckImplicitConversion. 4985static void DiagnoseImpCast(Sema &S, Expr *E, QualType T, 4986 SourceLocation CContext, unsigned diag, 4987 bool pruneControlFlow = false) { 4988 DiagnoseImpCast(S, E, E->getType(), T, CContext, diag, pruneControlFlow); 4989} 4990 4991/// Diagnose an implicit cast from a literal expression. Does not warn when the 4992/// cast wouldn't lose information. 4993void DiagnoseFloatingLiteralImpCast(Sema &S, FloatingLiteral *FL, QualType T, 4994 SourceLocation CContext) { 4995 // Try to convert the literal exactly to an integer. If we can, don't warn. 4996 bool isExact = false; 4997 const llvm::APFloat &Value = FL->getValue(); 4998 llvm::APSInt IntegerValue(S.Context.getIntWidth(T), 4999 T->hasUnsignedIntegerRepresentation()); 5000 if (Value.convertToInteger(IntegerValue, 5001 llvm::APFloat::rmTowardZero, &isExact) 5002 == llvm::APFloat::opOK && isExact) 5003 return; 5004 5005 SmallString<16> PrettySourceValue; 5006 Value.toString(PrettySourceValue); 5007 SmallString<16> PrettyTargetValue; 5008 if (T->isSpecificBuiltinType(BuiltinType::Bool)) 5009 PrettyTargetValue = IntegerValue == 0 ? "false" : "true"; 5010 else 5011 IntegerValue.toString(PrettyTargetValue); 5012 5013 S.Diag(FL->getExprLoc(), diag::warn_impcast_literal_float_to_integer) 5014 << FL->getType() << T.getUnqualifiedType() << PrettySourceValue 5015 << PrettyTargetValue << FL->getSourceRange() << SourceRange(CContext); 5016} 5017 5018std::string PrettyPrintInRange(const llvm::APSInt &Value, IntRange Range) { 5019 if (!Range.Width) return "0"; 5020 5021 llvm::APSInt ValueInRange = Value; 5022 ValueInRange.setIsSigned(!Range.NonNegative); 5023 ValueInRange = ValueInRange.trunc(Range.Width); 5024 return ValueInRange.toString(10); 5025} 5026 5027static bool IsImplicitBoolFloatConversion(Sema &S, Expr *Ex, bool ToBool) { 5028 if (!isa<ImplicitCastExpr>(Ex)) 5029 return false; 5030 5031 Expr *InnerE = Ex->IgnoreParenImpCasts(); 5032 const Type *Target = S.Context.getCanonicalType(Ex->getType()).getTypePtr(); 5033 const Type *Source = 5034 S.Context.getCanonicalType(InnerE->getType()).getTypePtr(); 5035 if (Target->isDependentType()) 5036 return false; 5037 5038 const BuiltinType *FloatCandidateBT = 5039 dyn_cast<BuiltinType>(ToBool ? Source : Target); 5040 const Type *BoolCandidateType = ToBool ? Target : Source; 5041 5042 return (BoolCandidateType->isSpecificBuiltinType(BuiltinType::Bool) && 5043 FloatCandidateBT && (FloatCandidateBT->isFloatingPoint())); 5044} 5045 5046void CheckImplicitArgumentConversions(Sema &S, CallExpr *TheCall, 5047 SourceLocation CC) { 5048 unsigned NumArgs = TheCall->getNumArgs(); 5049 for (unsigned i = 0; i < NumArgs; ++i) { 5050 Expr *CurrA = TheCall->getArg(i); 5051 if (!IsImplicitBoolFloatConversion(S, CurrA, true)) 5052 continue; 5053 5054 bool IsSwapped = ((i > 0) && 5055 IsImplicitBoolFloatConversion(S, TheCall->getArg(i - 1), false)); 5056 IsSwapped |= ((i < (NumArgs - 1)) && 5057 IsImplicitBoolFloatConversion(S, TheCall->getArg(i + 1), false)); 5058 if (IsSwapped) { 5059 // Warn on this floating-point to bool conversion. 5060 DiagnoseImpCast(S, CurrA->IgnoreParenImpCasts(), 5061 CurrA->getType(), CC, 5062 diag::warn_impcast_floating_point_to_bool); 5063 } 5064 } 5065} 5066 5067void CheckImplicitConversion(Sema &S, Expr *E, QualType T, 5068 SourceLocation CC, bool *ICContext = 0) { 5069 if (E->isTypeDependent() || E->isValueDependent()) return; 5070 5071 const Type *Source = S.Context.getCanonicalType(E->getType()).getTypePtr(); 5072 const Type *Target = S.Context.getCanonicalType(T).getTypePtr(); 5073 if (Source == Target) return; 5074 if (Target->isDependentType()) return; 5075 5076 // If the conversion context location is invalid don't complain. We also 5077 // don't want to emit a warning if the issue occurs from the expansion of 5078 // a system macro. The problem is that 'getSpellingLoc()' is slow, so we 5079 // delay this check as long as possible. Once we detect we are in that 5080 // scenario, we just return. 5081 if (CC.isInvalid()) 5082 return; 5083 5084 // Diagnose implicit casts to bool. 5085 if (Target->isSpecificBuiltinType(BuiltinType::Bool)) { 5086 if (isa<StringLiteral>(E)) 5087 // Warn on string literal to bool. Checks for string literals in logical 5088 // expressions, for instances, assert(0 && "error here"), is prevented 5089 // by a check in AnalyzeImplicitConversions(). 5090 return DiagnoseImpCast(S, E, T, CC, 5091 diag::warn_impcast_string_literal_to_bool); 5092 if (Source->isFunctionType()) { 5093 // Warn on function to bool. Checks free functions and static member 5094 // functions. Weakly imported functions are excluded from the check, 5095 // since it's common to test their value to check whether the linker 5096 // found a definition for them. 5097 ValueDecl *D = 0; 5098 if (DeclRefExpr* R = dyn_cast<DeclRefExpr>(E)) { 5099 D = R->getDecl(); 5100 } else if (MemberExpr *M = dyn_cast<MemberExpr>(E)) { 5101 D = M->getMemberDecl(); 5102 } 5103 5104 if (D && !D->isWeak()) { 5105 if (FunctionDecl* F = dyn_cast<FunctionDecl>(D)) { 5106 S.Diag(E->getExprLoc(), diag::warn_impcast_function_to_bool) 5107 << F << E->getSourceRange() << SourceRange(CC); 5108 S.Diag(E->getExprLoc(), diag::note_function_to_bool_silence) 5109 << FixItHint::CreateInsertion(E->getExprLoc(), "&"); 5110 QualType ReturnType; 5111 UnresolvedSet<4> NonTemplateOverloads; 5112 S.tryExprAsCall(*E, ReturnType, NonTemplateOverloads); 5113 if (!ReturnType.isNull() 5114 && ReturnType->isSpecificBuiltinType(BuiltinType::Bool)) 5115 S.Diag(E->getExprLoc(), diag::note_function_to_bool_call) 5116 << FixItHint::CreateInsertion( 5117 S.getPreprocessor().getLocForEndOfToken(E->getLocEnd()), "()"); 5118 return; 5119 } 5120 } 5121 } 5122 } 5123 5124 // Strip vector types. 5125 if (isa<VectorType>(Source)) { 5126 if (!isa<VectorType>(Target)) { 5127 if (S.SourceMgr.isInSystemMacro(CC)) 5128 return; 5129 return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_vector_scalar); 5130 } 5131 5132 // If the vector cast is cast between two vectors of the same size, it is 5133 // a bitcast, not a conversion. 5134 if (S.Context.getTypeSize(Source) == S.Context.getTypeSize(Target)) 5135 return; 5136 5137 Source = cast<VectorType>(Source)->getElementType().getTypePtr(); 5138 Target = cast<VectorType>(Target)->getElementType().getTypePtr(); 5139 } 5140 5141 // Strip complex types. 5142 if (isa<ComplexType>(Source)) { 5143 if (!isa<ComplexType>(Target)) { 5144 if (S.SourceMgr.isInSystemMacro(CC)) 5145 return; 5146 5147 return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_complex_scalar); 5148 } 5149 5150 Source = cast<ComplexType>(Source)->getElementType().getTypePtr(); 5151 Target = cast<ComplexType>(Target)->getElementType().getTypePtr(); 5152 } 5153 5154 const BuiltinType *SourceBT = dyn_cast<BuiltinType>(Source); 5155 const BuiltinType *TargetBT = dyn_cast<BuiltinType>(Target); 5156 5157 // If the source is floating point... 5158 if (SourceBT && SourceBT->isFloatingPoint()) { 5159 // ...and the target is floating point... 5160 if (TargetBT && TargetBT->isFloatingPoint()) { 5161 // ...then warn if we're dropping FP rank. 5162 5163 // Builtin FP kinds are ordered by increasing FP rank. 5164 if (SourceBT->getKind() > TargetBT->getKind()) { 5165 // Don't warn about float constants that are precisely 5166 // representable in the target type. 5167 Expr::EvalResult result; 5168 if (E->EvaluateAsRValue(result, S.Context)) { 5169 // Value might be a float, a float vector, or a float complex. 5170 if (IsSameFloatAfterCast(result.Val, 5171 S.Context.getFloatTypeSemantics(QualType(TargetBT, 0)), 5172 S.Context.getFloatTypeSemantics(QualType(SourceBT, 0)))) 5173 return; 5174 } 5175 5176 if (S.SourceMgr.isInSystemMacro(CC)) 5177 return; 5178 5179 DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_float_precision); 5180 } 5181 return; 5182 } 5183 5184 // If the target is integral, always warn. 5185 if (TargetBT && TargetBT->isInteger()) { 5186 if (S.SourceMgr.isInSystemMacro(CC)) 5187 return; 5188 5189 Expr *InnerE = E->IgnoreParenImpCasts(); 5190 // We also want to warn on, e.g., "int i = -1.234" 5191 if (UnaryOperator *UOp = dyn_cast<UnaryOperator>(InnerE)) 5192 if (UOp->getOpcode() == UO_Minus || UOp->getOpcode() == UO_Plus) 5193 InnerE = UOp->getSubExpr()->IgnoreParenImpCasts(); 5194 5195 if (FloatingLiteral *FL = dyn_cast<FloatingLiteral>(InnerE)) { 5196 DiagnoseFloatingLiteralImpCast(S, FL, T, CC); 5197 } else { 5198 DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_float_integer); 5199 } 5200 } 5201 5202 // If the target is bool, warn if expr is a function or method call. 5203 if (Target->isSpecificBuiltinType(BuiltinType::Bool) && 5204 isa<CallExpr>(E)) { 5205 // Check last argument of function call to see if it is an 5206 // implicit cast from a type matching the type the result 5207 // is being cast to. 5208 CallExpr *CEx = cast<CallExpr>(E); 5209 unsigned NumArgs = CEx->getNumArgs(); 5210 if (NumArgs > 0) { 5211 Expr *LastA = CEx->getArg(NumArgs - 1); 5212 Expr *InnerE = LastA->IgnoreParenImpCasts(); 5213 const Type *InnerType = 5214 S.Context.getCanonicalType(InnerE->getType()).getTypePtr(); 5215 if (isa<ImplicitCastExpr>(LastA) && (InnerType == Target)) { 5216 // Warn on this floating-point to bool conversion 5217 DiagnoseImpCast(S, E, T, CC, 5218 diag::warn_impcast_floating_point_to_bool); 5219 } 5220 } 5221 } 5222 return; 5223 } 5224 5225 if ((E->isNullPointerConstant(S.Context, Expr::NPC_ValueDependentIsNotNull) 5226 == Expr::NPCK_GNUNull) && !Target->isAnyPointerType() 5227 && !Target->isBlockPointerType() && !Target->isMemberPointerType() 5228 && Target->isScalarType() && !Target->isNullPtrType()) { 5229 SourceLocation Loc = E->getSourceRange().getBegin(); 5230 if (Loc.isMacroID()) 5231 Loc = S.SourceMgr.getImmediateExpansionRange(Loc).first; 5232 if (!Loc.isMacroID() || CC.isMacroID()) 5233 S.Diag(Loc, diag::warn_impcast_null_pointer_to_integer) 5234 << T << clang::SourceRange(CC) 5235 << FixItHint::CreateReplacement(Loc, S.getFixItZeroLiteralForType(T)); 5236 } 5237 5238 if (!Source->isIntegerType() || !Target->isIntegerType()) 5239 return; 5240 5241 // TODO: remove this early return once the false positives for constant->bool 5242 // in templates, macros, etc, are reduced or removed. 5243 if (Target->isSpecificBuiltinType(BuiltinType::Bool)) 5244 return; 5245 5246 IntRange SourceRange = GetExprRange(S.Context, E); 5247 IntRange TargetRange = IntRange::forTargetOfCanonicalType(S.Context, Target); 5248 5249 if (SourceRange.Width > TargetRange.Width) { 5250 // If the source is a constant, use a default-on diagnostic. 5251 // TODO: this should happen for bitfield stores, too. 5252 llvm::APSInt Value(32); 5253 if (E->isIntegerConstantExpr(Value, S.Context)) { 5254 if (S.SourceMgr.isInSystemMacro(CC)) 5255 return; 5256 5257 std::string PrettySourceValue = Value.toString(10); 5258 std::string PrettyTargetValue = PrettyPrintInRange(Value, TargetRange); 5259 5260 S.DiagRuntimeBehavior(E->getExprLoc(), E, 5261 S.PDiag(diag::warn_impcast_integer_precision_constant) 5262 << PrettySourceValue << PrettyTargetValue 5263 << E->getType() << T << E->getSourceRange() 5264 << clang::SourceRange(CC)); 5265 return; 5266 } 5267 5268 // People want to build with -Wshorten-64-to-32 and not -Wconversion. 5269 if (S.SourceMgr.isInSystemMacro(CC)) 5270 return; 5271 5272 if (TargetRange.Width == 32 && S.Context.getIntWidth(E->getType()) == 64) 5273 return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_integer_64_32, 5274 /* pruneControlFlow */ true); 5275 return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_integer_precision); 5276 } 5277 5278 if ((TargetRange.NonNegative && !SourceRange.NonNegative) || 5279 (!TargetRange.NonNegative && SourceRange.NonNegative && 5280 SourceRange.Width == TargetRange.Width)) { 5281 5282 if (S.SourceMgr.isInSystemMacro(CC)) 5283 return; 5284 5285 unsigned DiagID = diag::warn_impcast_integer_sign; 5286 5287 // Traditionally, gcc has warned about this under -Wsign-compare. 5288 // We also want to warn about it in -Wconversion. 5289 // So if -Wconversion is off, use a completely identical diagnostic 5290 // in the sign-compare group. 5291 // The conditional-checking code will 5292 if (ICContext) { 5293 DiagID = diag::warn_impcast_integer_sign_conditional; 5294 *ICContext = true; 5295 } 5296 5297 return DiagnoseImpCast(S, E, T, CC, DiagID); 5298 } 5299 5300 // Diagnose conversions between different enumeration types. 5301 // In C, we pretend that the type of an EnumConstantDecl is its enumeration 5302 // type, to give us better diagnostics. 5303 QualType SourceType = E->getType(); 5304 if (!S.getLangOpts().CPlusPlus) { 5305 if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) 5306 if (EnumConstantDecl *ECD = dyn_cast<EnumConstantDecl>(DRE->getDecl())) { 5307 EnumDecl *Enum = cast<EnumDecl>(ECD->getDeclContext()); 5308 SourceType = S.Context.getTypeDeclType(Enum); 5309 Source = S.Context.getCanonicalType(SourceType).getTypePtr(); 5310 } 5311 } 5312 5313 if (const EnumType *SourceEnum = Source->getAs<EnumType>()) 5314 if (const EnumType *TargetEnum = Target->getAs<EnumType>()) 5315 if (SourceEnum->getDecl()->hasNameForLinkage() && 5316 TargetEnum->getDecl()->hasNameForLinkage() && 5317 SourceEnum != TargetEnum) { 5318 if (S.SourceMgr.isInSystemMacro(CC)) 5319 return; 5320 5321 return DiagnoseImpCast(S, E, SourceType, T, CC, 5322 diag::warn_impcast_different_enum_types); 5323 } 5324 5325 return; 5326} 5327 5328void CheckConditionalOperator(Sema &S, ConditionalOperator *E, 5329 SourceLocation CC, QualType T); 5330 5331void CheckConditionalOperand(Sema &S, Expr *E, QualType T, 5332 SourceLocation CC, bool &ICContext) { 5333 E = E->IgnoreParenImpCasts(); 5334 5335 if (isa<ConditionalOperator>(E)) 5336 return CheckConditionalOperator(S, cast<ConditionalOperator>(E), CC, T); 5337 5338 AnalyzeImplicitConversions(S, E, CC); 5339 if (E->getType() != T) 5340 return CheckImplicitConversion(S, E, T, CC, &ICContext); 5341 return; 5342} 5343 5344void CheckConditionalOperator(Sema &S, ConditionalOperator *E, 5345 SourceLocation CC, QualType T) { 5346 AnalyzeImplicitConversions(S, E->getCond(), CC); 5347 5348 bool Suspicious = false; 5349 CheckConditionalOperand(S, E->getTrueExpr(), T, CC, Suspicious); 5350 CheckConditionalOperand(S, E->getFalseExpr(), T, CC, Suspicious); 5351 5352 // If -Wconversion would have warned about either of the candidates 5353 // for a signedness conversion to the context type... 5354 if (!Suspicious) return; 5355 5356 // ...but it's currently ignored... 5357 if (S.Diags.getDiagnosticLevel(diag::warn_impcast_integer_sign_conditional, 5358 CC)) 5359 return; 5360 5361 // ...then check whether it would have warned about either of the 5362 // candidates for a signedness conversion to the condition type. 5363 if (E->getType() == T) return; 5364 5365 Suspicious = false; 5366 CheckImplicitConversion(S, E->getTrueExpr()->IgnoreParenImpCasts(), 5367 E->getType(), CC, &Suspicious); 5368 if (!Suspicious) 5369 CheckImplicitConversion(S, E->getFalseExpr()->IgnoreParenImpCasts(), 5370 E->getType(), CC, &Suspicious); 5371} 5372 5373/// AnalyzeImplicitConversions - Find and report any interesting 5374/// implicit conversions in the given expression. There are a couple 5375/// of competing diagnostics here, -Wconversion and -Wsign-compare. 5376void AnalyzeImplicitConversions(Sema &S, Expr *OrigE, SourceLocation CC) { 5377 QualType T = OrigE->getType(); 5378 Expr *E = OrigE->IgnoreParenImpCasts(); 5379 5380 if (E->isTypeDependent() || E->isValueDependent()) 5381 return; 5382 5383 // For conditional operators, we analyze the arguments as if they 5384 // were being fed directly into the output. 5385 if (isa<ConditionalOperator>(E)) { 5386 ConditionalOperator *CO = cast<ConditionalOperator>(E); 5387 CheckConditionalOperator(S, CO, CC, T); 5388 return; 5389 } 5390 5391 // Check implicit argument conversions for function calls. 5392 if (CallExpr *Call = dyn_cast<CallExpr>(E)) 5393 CheckImplicitArgumentConversions(S, Call, CC); 5394 5395 // Go ahead and check any implicit conversions we might have skipped. 5396 // The non-canonical typecheck is just an optimization; 5397 // CheckImplicitConversion will filter out dead implicit conversions. 5398 if (E->getType() != T) 5399 CheckImplicitConversion(S, E, T, CC); 5400 5401 // Now continue drilling into this expression. 5402 5403 if (PseudoObjectExpr * POE = dyn_cast<PseudoObjectExpr>(E)) { 5404 if (POE->getResultExpr()) 5405 E = POE->getResultExpr(); 5406 } 5407 5408 if (const OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(E)) 5409 return AnalyzeImplicitConversions(S, OVE->getSourceExpr(), CC); 5410 5411 // Skip past explicit casts. 5412 if (isa<ExplicitCastExpr>(E)) { 5413 E = cast<ExplicitCastExpr>(E)->getSubExpr()->IgnoreParenImpCasts(); 5414 return AnalyzeImplicitConversions(S, E, CC); 5415 } 5416 5417 if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) { 5418 // Do a somewhat different check with comparison operators. 5419 if (BO->isComparisonOp()) 5420 return AnalyzeComparison(S, BO); 5421 5422 // And with simple assignments. 5423 if (BO->getOpcode() == BO_Assign) 5424 return AnalyzeAssignment(S, BO); 5425 } 5426 5427 // These break the otherwise-useful invariant below. Fortunately, 5428 // we don't really need to recurse into them, because any internal 5429 // expressions should have been analyzed already when they were 5430 // built into statements. 5431 if (isa<StmtExpr>(E)) return; 5432 5433 // Don't descend into unevaluated contexts. 5434 if (isa<UnaryExprOrTypeTraitExpr>(E)) return; 5435 5436 // Now just recurse over the expression's children. 5437 CC = E->getExprLoc(); 5438 BinaryOperator *BO = dyn_cast<BinaryOperator>(E); 5439 bool IsLogicalOperator = BO && BO->isLogicalOp(); 5440 for (Stmt::child_range I = E->children(); I; ++I) { 5441 Expr *ChildExpr = dyn_cast_or_null<Expr>(*I); 5442 if (!ChildExpr) 5443 continue; 5444 5445 if (IsLogicalOperator && 5446 isa<StringLiteral>(ChildExpr->IgnoreParenImpCasts())) 5447 // Ignore checking string literals that are in logical operators. 5448 continue; 5449 AnalyzeImplicitConversions(S, ChildExpr, CC); 5450 } 5451} 5452 5453} // end anonymous namespace 5454 5455/// Diagnoses "dangerous" implicit conversions within the given 5456/// expression (which is a full expression). Implements -Wconversion 5457/// and -Wsign-compare. 5458/// 5459/// \param CC the "context" location of the implicit conversion, i.e. 5460/// the most location of the syntactic entity requiring the implicit 5461/// conversion 5462void Sema::CheckImplicitConversions(Expr *E, SourceLocation CC) { 5463 // Don't diagnose in unevaluated contexts. 5464 if (isUnevaluatedContext()) 5465 return; 5466 5467 // Don't diagnose for value- or type-dependent expressions. 5468 if (E->isTypeDependent() || E->isValueDependent()) 5469 return; 5470 5471 // Check for array bounds violations in cases where the check isn't triggered 5472 // elsewhere for other Expr types (like BinaryOperators), e.g. when an 5473 // ArraySubscriptExpr is on the RHS of a variable initialization. 5474 CheckArrayAccess(E); 5475 5476 // This is not the right CC for (e.g.) a variable initialization. 5477 AnalyzeImplicitConversions(*this, E, CC); 5478} 5479 5480/// Diagnose when expression is an integer constant expression and its evaluation 5481/// results in integer overflow 5482void Sema::CheckForIntOverflow (Expr *E) { 5483 if (isa<BinaryOperator>(E->IgnoreParens())) { 5484 llvm::SmallVector<PartialDiagnosticAt, 4> Diags; 5485 E->EvaluateForOverflow(Context, &Diags); 5486 } 5487} 5488 5489namespace { 5490/// \brief Visitor for expressions which looks for unsequenced operations on the 5491/// same object. 5492class SequenceChecker : public EvaluatedExprVisitor<SequenceChecker> { 5493 typedef EvaluatedExprVisitor<SequenceChecker> Base; 5494 5495 /// \brief A tree of sequenced regions within an expression. Two regions are 5496 /// unsequenced if one is an ancestor or a descendent of the other. When we 5497 /// finish processing an expression with sequencing, such as a comma 5498 /// expression, we fold its tree nodes into its parent, since they are 5499 /// unsequenced with respect to nodes we will visit later. 5500 class SequenceTree { 5501 struct Value { 5502 explicit Value(unsigned Parent) : Parent(Parent), Merged(false) {} 5503 unsigned Parent : 31; 5504 bool Merged : 1; 5505 }; 5506 llvm::SmallVector<Value, 8> Values; 5507 5508 public: 5509 /// \brief A region within an expression which may be sequenced with respect 5510 /// to some other region. 5511 class Seq { 5512 explicit Seq(unsigned N) : Index(N) {} 5513 unsigned Index; 5514 friend class SequenceTree; 5515 public: 5516 Seq() : Index(0) {} 5517 }; 5518 5519 SequenceTree() { Values.push_back(Value(0)); } 5520 Seq root() const { return Seq(0); } 5521 5522 /// \brief Create a new sequence of operations, which is an unsequenced 5523 /// subset of \p Parent. This sequence of operations is sequenced with 5524 /// respect to other children of \p Parent. 5525 Seq allocate(Seq Parent) { 5526 Values.push_back(Value(Parent.Index)); 5527 return Seq(Values.size() - 1); 5528 } 5529 5530 /// \brief Merge a sequence of operations into its parent. 5531 void merge(Seq S) { 5532 Values[S.Index].Merged = true; 5533 } 5534 5535 /// \brief Determine whether two operations are unsequenced. This operation 5536 /// is asymmetric: \p Cur should be the more recent sequence, and \p Old 5537 /// should have been merged into its parent as appropriate. 5538 bool isUnsequenced(Seq Cur, Seq Old) { 5539 unsigned C = representative(Cur.Index); 5540 unsigned Target = representative(Old.Index); 5541 while (C >= Target) { 5542 if (C == Target) 5543 return true; 5544 C = Values[C].Parent; 5545 } 5546 return false; 5547 } 5548 5549 private: 5550 /// \brief Pick a representative for a sequence. 5551 unsigned representative(unsigned K) { 5552 if (Values[K].Merged) 5553 // Perform path compression as we go. 5554 return Values[K].Parent = representative(Values[K].Parent); 5555 return K; 5556 } 5557 }; 5558 5559 /// An object for which we can track unsequenced uses. 5560 typedef NamedDecl *Object; 5561 5562 /// Different flavors of object usage which we track. We only track the 5563 /// least-sequenced usage of each kind. 5564 enum UsageKind { 5565 /// A read of an object. Multiple unsequenced reads are OK. 5566 UK_Use, 5567 /// A modification of an object which is sequenced before the value 5568 /// computation of the expression, such as ++n in C++. 5569 UK_ModAsValue, 5570 /// A modification of an object which is not sequenced before the value 5571 /// computation of the expression, such as n++. 5572 UK_ModAsSideEffect, 5573 5574 UK_Count = UK_ModAsSideEffect + 1 5575 }; 5576 5577 struct Usage { 5578 Usage() : Use(0), Seq() {} 5579 Expr *Use; 5580 SequenceTree::Seq Seq; 5581 }; 5582 5583 struct UsageInfo { 5584 UsageInfo() : Diagnosed(false) {} 5585 Usage Uses[UK_Count]; 5586 /// Have we issued a diagnostic for this variable already? 5587 bool Diagnosed; 5588 }; 5589 typedef llvm::SmallDenseMap<Object, UsageInfo, 16> UsageInfoMap; 5590 5591 Sema &SemaRef; 5592 /// Sequenced regions within the expression. 5593 SequenceTree Tree; 5594 /// Declaration modifications and references which we have seen. 5595 UsageInfoMap UsageMap; 5596 /// The region we are currently within. 5597 SequenceTree::Seq Region; 5598 /// Filled in with declarations which were modified as a side-effect 5599 /// (that is, post-increment operations). 5600 llvm::SmallVectorImpl<std::pair<Object, Usage> > *ModAsSideEffect; 5601 /// Expressions to check later. We defer checking these to reduce 5602 /// stack usage. 5603 llvm::SmallVectorImpl<Expr*> &WorkList; 5604 5605 /// RAII object wrapping the visitation of a sequenced subexpression of an 5606 /// expression. At the end of this process, the side-effects of the evaluation 5607 /// become sequenced with respect to the value computation of the result, so 5608 /// we downgrade any UK_ModAsSideEffect within the evaluation to 5609 /// UK_ModAsValue. 5610 struct SequencedSubexpression { 5611 SequencedSubexpression(SequenceChecker &Self) 5612 : Self(Self), OldModAsSideEffect(Self.ModAsSideEffect) { 5613 Self.ModAsSideEffect = &ModAsSideEffect; 5614 } 5615 ~SequencedSubexpression() { 5616 for (unsigned I = 0, E = ModAsSideEffect.size(); I != E; ++I) { 5617 UsageInfo &U = Self.UsageMap[ModAsSideEffect[I].first]; 5618 U.Uses[UK_ModAsSideEffect] = ModAsSideEffect[I].second; 5619 Self.addUsage(U, ModAsSideEffect[I].first, 5620 ModAsSideEffect[I].second.Use, UK_ModAsValue); 5621 } 5622 Self.ModAsSideEffect = OldModAsSideEffect; 5623 } 5624 5625 SequenceChecker &Self; 5626 llvm::SmallVector<std::pair<Object, Usage>, 4> ModAsSideEffect; 5627 llvm::SmallVectorImpl<std::pair<Object, Usage> > *OldModAsSideEffect; 5628 }; 5629 5630 /// RAII object wrapping the visitation of a subexpression which we might 5631 /// choose to evaluate as a constant. If any subexpression is evaluated and 5632 /// found to be non-constant, this allows us to suppress the evaluation of 5633 /// the outer expression. 5634 class EvaluationTracker { 5635 public: 5636 EvaluationTracker(SequenceChecker &Self) 5637 : Self(Self), Prev(Self.EvalTracker), EvalOK(true) { 5638 Self.EvalTracker = this; 5639 } 5640 ~EvaluationTracker() { 5641 Self.EvalTracker = Prev; 5642 if (Prev) 5643 Prev->EvalOK &= EvalOK; 5644 } 5645 5646 bool evaluate(const Expr *E, bool &Result) { 5647 if (!EvalOK || E->isValueDependent()) 5648 return false; 5649 EvalOK = E->EvaluateAsBooleanCondition(Result, Self.SemaRef.Context); 5650 return EvalOK; 5651 } 5652 5653 private: 5654 SequenceChecker &Self; 5655 EvaluationTracker *Prev; 5656 bool EvalOK; 5657 } *EvalTracker; 5658 5659 /// \brief Find the object which is produced by the specified expression, 5660 /// if any. 5661 Object getObject(Expr *E, bool Mod) const { 5662 E = E->IgnoreParenCasts(); 5663 if (UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) { 5664 if (Mod && (UO->getOpcode() == UO_PreInc || UO->getOpcode() == UO_PreDec)) 5665 return getObject(UO->getSubExpr(), Mod); 5666 } else if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) { 5667 if (BO->getOpcode() == BO_Comma) 5668 return getObject(BO->getRHS(), Mod); 5669 if (Mod && BO->isAssignmentOp()) 5670 return getObject(BO->getLHS(), Mod); 5671 } else if (MemberExpr *ME = dyn_cast<MemberExpr>(E)) { 5672 // FIXME: Check for more interesting cases, like "x.n = ++x.n". 5673 if (isa<CXXThisExpr>(ME->getBase()->IgnoreParenCasts())) 5674 return ME->getMemberDecl(); 5675 } else if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) 5676 // FIXME: If this is a reference, map through to its value. 5677 return DRE->getDecl(); 5678 return 0; 5679 } 5680 5681 /// \brief Note that an object was modified or used by an expression. 5682 void addUsage(UsageInfo &UI, Object O, Expr *Ref, UsageKind UK) { 5683 Usage &U = UI.Uses[UK]; 5684 if (!U.Use || !Tree.isUnsequenced(Region, U.Seq)) { 5685 if (UK == UK_ModAsSideEffect && ModAsSideEffect) 5686 ModAsSideEffect->push_back(std::make_pair(O, U)); 5687 U.Use = Ref; 5688 U.Seq = Region; 5689 } 5690 } 5691 /// \brief Check whether a modification or use conflicts with a prior usage. 5692 void checkUsage(Object O, UsageInfo &UI, Expr *Ref, UsageKind OtherKind, 5693 bool IsModMod) { 5694 if (UI.Diagnosed) 5695 return; 5696 5697 const Usage &U = UI.Uses[OtherKind]; 5698 if (!U.Use || !Tree.isUnsequenced(Region, U.Seq)) 5699 return; 5700 5701 Expr *Mod = U.Use; 5702 Expr *ModOrUse = Ref; 5703 if (OtherKind == UK_Use) 5704 std::swap(Mod, ModOrUse); 5705 5706 SemaRef.Diag(Mod->getExprLoc(), 5707 IsModMod ? diag::warn_unsequenced_mod_mod 5708 : diag::warn_unsequenced_mod_use) 5709 << O << SourceRange(ModOrUse->getExprLoc()); 5710 UI.Diagnosed = true; 5711 } 5712 5713 void notePreUse(Object O, Expr *Use) { 5714 UsageInfo &U = UsageMap[O]; 5715 // Uses conflict with other modifications. 5716 checkUsage(O, U, Use, UK_ModAsValue, false); 5717 } 5718 void notePostUse(Object O, Expr *Use) { 5719 UsageInfo &U = UsageMap[O]; 5720 checkUsage(O, U, Use, UK_ModAsSideEffect, false); 5721 addUsage(U, O, Use, UK_Use); 5722 } 5723 5724 void notePreMod(Object O, Expr *Mod) { 5725 UsageInfo &U = UsageMap[O]; 5726 // Modifications conflict with other modifications and with uses. 5727 checkUsage(O, U, Mod, UK_ModAsValue, true); 5728 checkUsage(O, U, Mod, UK_Use, false); 5729 } 5730 void notePostMod(Object O, Expr *Use, UsageKind UK) { 5731 UsageInfo &U = UsageMap[O]; 5732 checkUsage(O, U, Use, UK_ModAsSideEffect, true); 5733 addUsage(U, O, Use, UK); 5734 } 5735 5736public: 5737 SequenceChecker(Sema &S, Expr *E, 5738 llvm::SmallVectorImpl<Expr*> &WorkList) 5739 : Base(S.Context), SemaRef(S), Region(Tree.root()), 5740 ModAsSideEffect(0), WorkList(WorkList), EvalTracker(0) { 5741 Visit(E); 5742 } 5743 5744 void VisitStmt(Stmt *S) { 5745 // Skip all statements which aren't expressions for now. 5746 } 5747 5748 void VisitExpr(Expr *E) { 5749 // By default, just recurse to evaluated subexpressions. 5750 Base::VisitStmt(E); 5751 } 5752 5753 void VisitCastExpr(CastExpr *E) { 5754 Object O = Object(); 5755 if (E->getCastKind() == CK_LValueToRValue) 5756 O = getObject(E->getSubExpr(), false); 5757 5758 if (O) 5759 notePreUse(O, E); 5760 VisitExpr(E); 5761 if (O) 5762 notePostUse(O, E); 5763 } 5764 5765 void VisitBinComma(BinaryOperator *BO) { 5766 // C++11 [expr.comma]p1: 5767 // Every value computation and side effect associated with the left 5768 // expression is sequenced before every value computation and side 5769 // effect associated with the right expression. 5770 SequenceTree::Seq LHS = Tree.allocate(Region); 5771 SequenceTree::Seq RHS = Tree.allocate(Region); 5772 SequenceTree::Seq OldRegion = Region; 5773 5774 { 5775 SequencedSubexpression SeqLHS(*this); 5776 Region = LHS; 5777 Visit(BO->getLHS()); 5778 } 5779 5780 Region = RHS; 5781 Visit(BO->getRHS()); 5782 5783 Region = OldRegion; 5784 5785 // Forget that LHS and RHS are sequenced. They are both unsequenced 5786 // with respect to other stuff. 5787 Tree.merge(LHS); 5788 Tree.merge(RHS); 5789 } 5790 5791 void VisitBinAssign(BinaryOperator *BO) { 5792 // The modification is sequenced after the value computation of the LHS 5793 // and RHS, so check it before inspecting the operands and update the 5794 // map afterwards. 5795 Object O = getObject(BO->getLHS(), true); 5796 if (!O) 5797 return VisitExpr(BO); 5798 5799 notePreMod(O, BO); 5800 5801 // C++11 [expr.ass]p7: 5802 // E1 op= E2 is equivalent to E1 = E1 op E2, except that E1 is evaluated 5803 // only once. 5804 // 5805 // Therefore, for a compound assignment operator, O is considered used 5806 // everywhere except within the evaluation of E1 itself. 5807 if (isa<CompoundAssignOperator>(BO)) 5808 notePreUse(O, BO); 5809 5810 Visit(BO->getLHS()); 5811 5812 if (isa<CompoundAssignOperator>(BO)) 5813 notePostUse(O, BO); 5814 5815 Visit(BO->getRHS()); 5816 5817 // C++11 [expr.ass]p1: 5818 // the assignment is sequenced [...] before the value computation of the 5819 // assignment expression. 5820 // C11 6.5.16/3 has no such rule. 5821 notePostMod(O, BO, SemaRef.getLangOpts().CPlusPlus ? UK_ModAsValue 5822 : UK_ModAsSideEffect); 5823 } 5824 void VisitCompoundAssignOperator(CompoundAssignOperator *CAO) { 5825 VisitBinAssign(CAO); 5826 } 5827 5828 void VisitUnaryPreInc(UnaryOperator *UO) { VisitUnaryPreIncDec(UO); } 5829 void VisitUnaryPreDec(UnaryOperator *UO) { VisitUnaryPreIncDec(UO); } 5830 void VisitUnaryPreIncDec(UnaryOperator *UO) { 5831 Object O = getObject(UO->getSubExpr(), true); 5832 if (!O) 5833 return VisitExpr(UO); 5834 5835 notePreMod(O, UO); 5836 Visit(UO->getSubExpr()); 5837 // C++11 [expr.pre.incr]p1: 5838 // the expression ++x is equivalent to x+=1 5839 notePostMod(O, UO, SemaRef.getLangOpts().CPlusPlus ? UK_ModAsValue 5840 : UK_ModAsSideEffect); 5841 } 5842 5843 void VisitUnaryPostInc(UnaryOperator *UO) { VisitUnaryPostIncDec(UO); } 5844 void VisitUnaryPostDec(UnaryOperator *UO) { VisitUnaryPostIncDec(UO); } 5845 void VisitUnaryPostIncDec(UnaryOperator *UO) { 5846 Object O = getObject(UO->getSubExpr(), true); 5847 if (!O) 5848 return VisitExpr(UO); 5849 5850 notePreMod(O, UO); 5851 Visit(UO->getSubExpr()); 5852 notePostMod(O, UO, UK_ModAsSideEffect); 5853 } 5854 5855 /// Don't visit the RHS of '&&' or '||' if it might not be evaluated. 5856 void VisitBinLOr(BinaryOperator *BO) { 5857 // The side-effects of the LHS of an '&&' are sequenced before the 5858 // value computation of the RHS, and hence before the value computation 5859 // of the '&&' itself, unless the LHS evaluates to zero. We treat them 5860 // as if they were unconditionally sequenced. 5861 EvaluationTracker Eval(*this); 5862 { 5863 SequencedSubexpression Sequenced(*this); 5864 Visit(BO->getLHS()); 5865 } 5866 5867 bool Result; 5868 if (Eval.evaluate(BO->getLHS(), Result)) { 5869 if (!Result) 5870 Visit(BO->getRHS()); 5871 } else { 5872 // Check for unsequenced operations in the RHS, treating it as an 5873 // entirely separate evaluation. 5874 // 5875 // FIXME: If there are operations in the RHS which are unsequenced 5876 // with respect to operations outside the RHS, and those operations 5877 // are unconditionally evaluated, diagnose them. 5878 WorkList.push_back(BO->getRHS()); 5879 } 5880 } 5881 void VisitBinLAnd(BinaryOperator *BO) { 5882 EvaluationTracker Eval(*this); 5883 { 5884 SequencedSubexpression Sequenced(*this); 5885 Visit(BO->getLHS()); 5886 } 5887 5888 bool Result; 5889 if (Eval.evaluate(BO->getLHS(), Result)) { 5890 if (Result) 5891 Visit(BO->getRHS()); 5892 } else { 5893 WorkList.push_back(BO->getRHS()); 5894 } 5895 } 5896 5897 // Only visit the condition, unless we can be sure which subexpression will 5898 // be chosen. 5899 void VisitAbstractConditionalOperator(AbstractConditionalOperator *CO) { 5900 EvaluationTracker Eval(*this); 5901 { 5902 SequencedSubexpression Sequenced(*this); 5903 Visit(CO->getCond()); 5904 } 5905 5906 bool Result; 5907 if (Eval.evaluate(CO->getCond(), Result)) 5908 Visit(Result ? CO->getTrueExpr() : CO->getFalseExpr()); 5909 else { 5910 WorkList.push_back(CO->getTrueExpr()); 5911 WorkList.push_back(CO->getFalseExpr()); 5912 } 5913 } 5914 5915 void VisitCallExpr(CallExpr *CE) { 5916 // C++11 [intro.execution]p15: 5917 // When calling a function [...], every value computation and side effect 5918 // associated with any argument expression, or with the postfix expression 5919 // designating the called function, is sequenced before execution of every 5920 // expression or statement in the body of the function [and thus before 5921 // the value computation of its result]. 5922 SequencedSubexpression Sequenced(*this); 5923 Base::VisitCallExpr(CE); 5924 5925 // FIXME: CXXNewExpr and CXXDeleteExpr implicitly call functions. 5926 } 5927 5928 void VisitCXXConstructExpr(CXXConstructExpr *CCE) { 5929 // This is a call, so all subexpressions are sequenced before the result. 5930 SequencedSubexpression Sequenced(*this); 5931 5932 if (!CCE->isListInitialization()) 5933 return VisitExpr(CCE); 5934 5935 // In C++11, list initializations are sequenced. 5936 llvm::SmallVector<SequenceTree::Seq, 32> Elts; 5937 SequenceTree::Seq Parent = Region; 5938 for (CXXConstructExpr::arg_iterator I = CCE->arg_begin(), 5939 E = CCE->arg_end(); 5940 I != E; ++I) { 5941 Region = Tree.allocate(Parent); 5942 Elts.push_back(Region); 5943 Visit(*I); 5944 } 5945 5946 // Forget that the initializers are sequenced. 5947 Region = Parent; 5948 for (unsigned I = 0; I < Elts.size(); ++I) 5949 Tree.merge(Elts[I]); 5950 } 5951 5952 void VisitInitListExpr(InitListExpr *ILE) { 5953 if (!SemaRef.getLangOpts().CPlusPlus11) 5954 return VisitExpr(ILE); 5955 5956 // In C++11, list initializations are sequenced. 5957 llvm::SmallVector<SequenceTree::Seq, 32> Elts; 5958 SequenceTree::Seq Parent = Region; 5959 for (unsigned I = 0; I < ILE->getNumInits(); ++I) { 5960 Expr *E = ILE->getInit(I); 5961 if (!E) continue; 5962 Region = Tree.allocate(Parent); 5963 Elts.push_back(Region); 5964 Visit(E); 5965 } 5966 5967 // Forget that the initializers are sequenced. 5968 Region = Parent; 5969 for (unsigned I = 0; I < Elts.size(); ++I) 5970 Tree.merge(Elts[I]); 5971 } 5972}; 5973} 5974 5975void Sema::CheckUnsequencedOperations(Expr *E) { 5976 llvm::SmallVector<Expr*, 8> WorkList; 5977 WorkList.push_back(E); 5978 while (!WorkList.empty()) { 5979 Expr *Item = WorkList.back(); 5980 WorkList.pop_back(); 5981 SequenceChecker(*this, Item, WorkList); 5982 } 5983} 5984 5985void Sema::CheckCompletedExpr(Expr *E, SourceLocation CheckLoc, 5986 bool IsConstexpr) { 5987 CheckImplicitConversions(E, CheckLoc); 5988 CheckUnsequencedOperations(E); 5989 if (!IsConstexpr && !E->isValueDependent()) 5990 CheckForIntOverflow(E); 5991} 5992 5993void Sema::CheckBitFieldInitialization(SourceLocation InitLoc, 5994 FieldDecl *BitField, 5995 Expr *Init) { 5996 (void) AnalyzeBitFieldAssignment(*this, BitField, Init, InitLoc); 5997} 5998 5999/// CheckParmsForFunctionDef - Check that the parameters of the given 6000/// function are appropriate for the definition of a function. This 6001/// takes care of any checks that cannot be performed on the 6002/// declaration itself, e.g., that the types of each of the function 6003/// parameters are complete. 6004bool Sema::CheckParmsForFunctionDef(ParmVarDecl *const *P, 6005 ParmVarDecl *const *PEnd, 6006 bool CheckParameterNames) { 6007 bool HasInvalidParm = false; 6008 for (; P != PEnd; ++P) { 6009 ParmVarDecl *Param = *P; 6010 6011 // C99 6.7.5.3p4: the parameters in a parameter type list in a 6012 // function declarator that is part of a function definition of 6013 // that function shall not have incomplete type. 6014 // 6015 // This is also C++ [dcl.fct]p6. 6016 if (!Param->isInvalidDecl() && 6017 RequireCompleteType(Param->getLocation(), Param->getType(), 6018 diag::err_typecheck_decl_incomplete_type)) { 6019 Param->setInvalidDecl(); 6020 HasInvalidParm = true; 6021 } 6022 6023 // C99 6.9.1p5: If the declarator includes a parameter type list, the 6024 // declaration of each parameter shall include an identifier. 6025 if (CheckParameterNames && 6026 Param->getIdentifier() == 0 && 6027 !Param->isImplicit() && 6028 !getLangOpts().CPlusPlus) 6029 Diag(Param->getLocation(), diag::err_parameter_name_omitted); 6030 6031 // C99 6.7.5.3p12: 6032 // If the function declarator is not part of a definition of that 6033 // function, parameters may have incomplete type and may use the [*] 6034 // notation in their sequences of declarator specifiers to specify 6035 // variable length array types. 6036 QualType PType = Param->getOriginalType(); 6037 while (const ArrayType *AT = Context.getAsArrayType(PType)) { 6038 if (AT->getSizeModifier() == ArrayType::Star) { 6039 // FIXME: This diagnostic should point the '[*]' if source-location 6040 // information is added for it. 6041 Diag(Param->getLocation(), diag::err_array_star_in_function_definition); 6042 break; 6043 } 6044 PType= AT->getElementType(); 6045 } 6046 6047 // MSVC destroys objects passed by value in the callee. Therefore a 6048 // function definition which takes such a parameter must be able to call the 6049 // object's destructor. 6050 if (getLangOpts().CPlusPlus && 6051 Context.getTargetInfo().getCXXABI().isArgumentDestroyedByCallee()) { 6052 if (const RecordType *RT = Param->getType()->getAs<RecordType>()) 6053 FinalizeVarWithDestructor(Param, RT); 6054 } 6055 } 6056 6057 return HasInvalidParm; 6058} 6059 6060/// CheckCastAlign - Implements -Wcast-align, which warns when a 6061/// pointer cast increases the alignment requirements. 6062void Sema::CheckCastAlign(Expr *Op, QualType T, SourceRange TRange) { 6063 // This is actually a lot of work to potentially be doing on every 6064 // cast; don't do it if we're ignoring -Wcast_align (as is the default). 6065 if (getDiagnostics().getDiagnosticLevel(diag::warn_cast_align, 6066 TRange.getBegin()) 6067 == DiagnosticsEngine::Ignored) 6068 return; 6069 6070 // Ignore dependent types. 6071 if (T->isDependentType() || Op->getType()->isDependentType()) 6072 return; 6073 6074 // Require that the destination be a pointer type. 6075 const PointerType *DestPtr = T->getAs<PointerType>(); 6076 if (!DestPtr) return; 6077 6078 // If the destination has alignment 1, we're done. 6079 QualType DestPointee = DestPtr->getPointeeType(); 6080 if (DestPointee->isIncompleteType()) return; 6081 CharUnits DestAlign = Context.getTypeAlignInChars(DestPointee); 6082 if (DestAlign.isOne()) return; 6083 6084 // Require that the source be a pointer type. 6085 const PointerType *SrcPtr = Op->getType()->getAs<PointerType>(); 6086 if (!SrcPtr) return; 6087 QualType SrcPointee = SrcPtr->getPointeeType(); 6088 6089 // Whitelist casts from cv void*. We already implicitly 6090 // whitelisted casts to cv void*, since they have alignment 1. 6091 // Also whitelist casts involving incomplete types, which implicitly 6092 // includes 'void'. 6093 if (SrcPointee->isIncompleteType()) return; 6094 6095 CharUnits SrcAlign = Context.getTypeAlignInChars(SrcPointee); 6096 if (SrcAlign >= DestAlign) return; 6097 6098 Diag(TRange.getBegin(), diag::warn_cast_align) 6099 << Op->getType() << T 6100 << static_cast<unsigned>(SrcAlign.getQuantity()) 6101 << static_cast<unsigned>(DestAlign.getQuantity()) 6102 << TRange << Op->getSourceRange(); 6103} 6104 6105static const Type* getElementType(const Expr *BaseExpr) { 6106 const Type* EltType = BaseExpr->getType().getTypePtr(); 6107 if (EltType->isAnyPointerType()) 6108 return EltType->getPointeeType().getTypePtr(); 6109 else if (EltType->isArrayType()) 6110 return EltType->getBaseElementTypeUnsafe(); 6111 return EltType; 6112} 6113 6114/// \brief Check whether this array fits the idiom of a size-one tail padded 6115/// array member of a struct. 6116/// 6117/// We avoid emitting out-of-bounds access warnings for such arrays as they are 6118/// commonly used to emulate flexible arrays in C89 code. 6119static bool IsTailPaddedMemberArray(Sema &S, llvm::APInt Size, 6120 const NamedDecl *ND) { 6121 if (Size != 1 || !ND) return false; 6122 6123 const FieldDecl *FD = dyn_cast<FieldDecl>(ND); 6124 if (!FD) return false; 6125 6126 // Don't consider sizes resulting from macro expansions or template argument 6127 // substitution to form C89 tail-padded arrays. 6128 6129 TypeSourceInfo *TInfo = FD->getTypeSourceInfo(); 6130 while (TInfo) { 6131 TypeLoc TL = TInfo->getTypeLoc(); 6132 // Look through typedefs. 6133 if (TypedefTypeLoc TTL = TL.getAs<TypedefTypeLoc>()) { 6134 const TypedefNameDecl *TDL = TTL.getTypedefNameDecl(); 6135 TInfo = TDL->getTypeSourceInfo(); 6136 continue; 6137 } 6138 if (ConstantArrayTypeLoc CTL = TL.getAs<ConstantArrayTypeLoc>()) { 6139 const Expr *SizeExpr = dyn_cast<IntegerLiteral>(CTL.getSizeExpr()); 6140 if (!SizeExpr || SizeExpr->getExprLoc().isMacroID()) 6141 return false; 6142 } 6143 break; 6144 } 6145 6146 const RecordDecl *RD = dyn_cast<RecordDecl>(FD->getDeclContext()); 6147 if (!RD) return false; 6148 if (RD->isUnion()) return false; 6149 if (const CXXRecordDecl *CRD = dyn_cast<CXXRecordDecl>(RD)) { 6150 if (!CRD->isStandardLayout()) return false; 6151 } 6152 6153 // See if this is the last field decl in the record. 6154 const Decl *D = FD; 6155 while ((D = D->getNextDeclInContext())) 6156 if (isa<FieldDecl>(D)) 6157 return false; 6158 return true; 6159} 6160 6161void Sema::CheckArrayAccess(const Expr *BaseExpr, const Expr *IndexExpr, 6162 const ArraySubscriptExpr *ASE, 6163 bool AllowOnePastEnd, bool IndexNegated) { 6164 IndexExpr = IndexExpr->IgnoreParenImpCasts(); 6165 if (IndexExpr->isValueDependent()) 6166 return; 6167 6168 const Type *EffectiveType = getElementType(BaseExpr); 6169 BaseExpr = BaseExpr->IgnoreParenCasts(); 6170 const ConstantArrayType *ArrayTy = 6171 Context.getAsConstantArrayType(BaseExpr->getType()); 6172 if (!ArrayTy) 6173 return; 6174 6175 llvm::APSInt index; 6176 if (!IndexExpr->EvaluateAsInt(index, Context)) 6177 return; 6178 if (IndexNegated) 6179 index = -index; 6180 6181 const NamedDecl *ND = NULL; 6182 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(BaseExpr)) 6183 ND = dyn_cast<NamedDecl>(DRE->getDecl()); 6184 if (const MemberExpr *ME = dyn_cast<MemberExpr>(BaseExpr)) 6185 ND = dyn_cast<NamedDecl>(ME->getMemberDecl()); 6186 6187 if (index.isUnsigned() || !index.isNegative()) { 6188 llvm::APInt size = ArrayTy->getSize(); 6189 if (!size.isStrictlyPositive()) 6190 return; 6191 6192 const Type* BaseType = getElementType(BaseExpr); 6193 if (BaseType != EffectiveType) { 6194 // Make sure we're comparing apples to apples when comparing index to size 6195 uint64_t ptrarith_typesize = Context.getTypeSize(EffectiveType); 6196 uint64_t array_typesize = Context.getTypeSize(BaseType); 6197 // Handle ptrarith_typesize being zero, such as when casting to void* 6198 if (!ptrarith_typesize) ptrarith_typesize = 1; 6199 if (ptrarith_typesize != array_typesize) { 6200 // There's a cast to a different size type involved 6201 uint64_t ratio = array_typesize / ptrarith_typesize; 6202 // TODO: Be smarter about handling cases where array_typesize is not a 6203 // multiple of ptrarith_typesize 6204 if (ptrarith_typesize * ratio == array_typesize) 6205 size *= llvm::APInt(size.getBitWidth(), ratio); 6206 } 6207 } 6208 6209 if (size.getBitWidth() > index.getBitWidth()) 6210 index = index.zext(size.getBitWidth()); 6211 else if (size.getBitWidth() < index.getBitWidth()) 6212 size = size.zext(index.getBitWidth()); 6213 6214 // For array subscripting the index must be less than size, but for pointer 6215 // arithmetic also allow the index (offset) to be equal to size since 6216 // computing the next address after the end of the array is legal and 6217 // commonly done e.g. in C++ iterators and range-based for loops. 6218 if (AllowOnePastEnd ? index.ule(size) : index.ult(size)) 6219 return; 6220 6221 // Also don't warn for arrays of size 1 which are members of some 6222 // structure. These are often used to approximate flexible arrays in C89 6223 // code. 6224 if (IsTailPaddedMemberArray(*this, size, ND)) 6225 return; 6226 6227 // Suppress the warning if the subscript expression (as identified by the 6228 // ']' location) and the index expression are both from macro expansions 6229 // within a system header. 6230 if (ASE) { 6231 SourceLocation RBracketLoc = SourceMgr.getSpellingLoc( 6232 ASE->getRBracketLoc()); 6233 if (SourceMgr.isInSystemHeader(RBracketLoc)) { 6234 SourceLocation IndexLoc = SourceMgr.getSpellingLoc( 6235 IndexExpr->getLocStart()); 6236 if (SourceMgr.isFromSameFile(RBracketLoc, IndexLoc)) 6237 return; 6238 } 6239 } 6240 6241 unsigned DiagID = diag::warn_ptr_arith_exceeds_bounds; 6242 if (ASE) 6243 DiagID = diag::warn_array_index_exceeds_bounds; 6244 6245 DiagRuntimeBehavior(BaseExpr->getLocStart(), BaseExpr, 6246 PDiag(DiagID) << index.toString(10, true) 6247 << size.toString(10, true) 6248 << (unsigned)size.getLimitedValue(~0U) 6249 << IndexExpr->getSourceRange()); 6250 } else { 6251 unsigned DiagID = diag::warn_array_index_precedes_bounds; 6252 if (!ASE) { 6253 DiagID = diag::warn_ptr_arith_precedes_bounds; 6254 if (index.isNegative()) index = -index; 6255 } 6256 6257 DiagRuntimeBehavior(BaseExpr->getLocStart(), BaseExpr, 6258 PDiag(DiagID) << index.toString(10, true) 6259 << IndexExpr->getSourceRange()); 6260 } 6261 6262 if (!ND) { 6263 // Try harder to find a NamedDecl to point at in the note. 6264 while (const ArraySubscriptExpr *ASE = 6265 dyn_cast<ArraySubscriptExpr>(BaseExpr)) 6266 BaseExpr = ASE->getBase()->IgnoreParenCasts(); 6267 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(BaseExpr)) 6268 ND = dyn_cast<NamedDecl>(DRE->getDecl()); 6269 if (const MemberExpr *ME = dyn_cast<MemberExpr>(BaseExpr)) 6270 ND = dyn_cast<NamedDecl>(ME->getMemberDecl()); 6271 } 6272 6273 if (ND) 6274 DiagRuntimeBehavior(ND->getLocStart(), BaseExpr, 6275 PDiag(diag::note_array_index_out_of_bounds) 6276 << ND->getDeclName()); 6277} 6278 6279void Sema::CheckArrayAccess(const Expr *expr) { 6280 int AllowOnePastEnd = 0; 6281 while (expr) { 6282 expr = expr->IgnoreParenImpCasts(); 6283 switch (expr->getStmtClass()) { 6284 case Stmt::ArraySubscriptExprClass: { 6285 const ArraySubscriptExpr *ASE = cast<ArraySubscriptExpr>(expr); 6286 CheckArrayAccess(ASE->getBase(), ASE->getIdx(), ASE, 6287 AllowOnePastEnd > 0); 6288 return; 6289 } 6290 case Stmt::UnaryOperatorClass: { 6291 // Only unwrap the * and & unary operators 6292 const UnaryOperator *UO = cast<UnaryOperator>(expr); 6293 expr = UO->getSubExpr(); 6294 switch (UO->getOpcode()) { 6295 case UO_AddrOf: 6296 AllowOnePastEnd++; 6297 break; 6298 case UO_Deref: 6299 AllowOnePastEnd--; 6300 break; 6301 default: 6302 return; 6303 } 6304 break; 6305 } 6306 case Stmt::ConditionalOperatorClass: { 6307 const ConditionalOperator *cond = cast<ConditionalOperator>(expr); 6308 if (const Expr *lhs = cond->getLHS()) 6309 CheckArrayAccess(lhs); 6310 if (const Expr *rhs = cond->getRHS()) 6311 CheckArrayAccess(rhs); 6312 return; 6313 } 6314 default: 6315 return; 6316 } 6317 } 6318} 6319 6320//===--- CHECK: Objective-C retain cycles ----------------------------------// 6321 6322namespace { 6323 struct RetainCycleOwner { 6324 RetainCycleOwner() : Variable(0), Indirect(false) {} 6325 VarDecl *Variable; 6326 SourceRange Range; 6327 SourceLocation Loc; 6328 bool Indirect; 6329 6330 void setLocsFrom(Expr *e) { 6331 Loc = e->getExprLoc(); 6332 Range = e->getSourceRange(); 6333 } 6334 }; 6335} 6336 6337/// Consider whether capturing the given variable can possibly lead to 6338/// a retain cycle. 6339static bool considerVariable(VarDecl *var, Expr *ref, RetainCycleOwner &owner) { 6340 // In ARC, it's captured strongly iff the variable has __strong 6341 // lifetime. In MRR, it's captured strongly if the variable is 6342 // __block and has an appropriate type. 6343 if (var->getType().getObjCLifetime() != Qualifiers::OCL_Strong) 6344 return false; 6345 6346 owner.Variable = var; 6347 if (ref) 6348 owner.setLocsFrom(ref); 6349 return true; 6350} 6351 6352static bool findRetainCycleOwner(Sema &S, Expr *e, RetainCycleOwner &owner) { 6353 while (true) { 6354 e = e->IgnoreParens(); 6355 if (CastExpr *cast = dyn_cast<CastExpr>(e)) { 6356 switch (cast->getCastKind()) { 6357 case CK_BitCast: 6358 case CK_LValueBitCast: 6359 case CK_LValueToRValue: 6360 case CK_ARCReclaimReturnedObject: 6361 e = cast->getSubExpr(); 6362 continue; 6363 6364 default: 6365 return false; 6366 } 6367 } 6368 6369 if (ObjCIvarRefExpr *ref = dyn_cast<ObjCIvarRefExpr>(e)) { 6370 ObjCIvarDecl *ivar = ref->getDecl(); 6371 if (ivar->getType().getObjCLifetime() != Qualifiers::OCL_Strong) 6372 return false; 6373 6374 // Try to find a retain cycle in the base. 6375 if (!findRetainCycleOwner(S, ref->getBase(), owner)) 6376 return false; 6377 6378 if (ref->isFreeIvar()) owner.setLocsFrom(ref); 6379 owner.Indirect = true; 6380 return true; 6381 } 6382 6383 if (DeclRefExpr *ref = dyn_cast<DeclRefExpr>(e)) { 6384 VarDecl *var = dyn_cast<VarDecl>(ref->getDecl()); 6385 if (!var) return false; 6386 return considerVariable(var, ref, owner); 6387 } 6388 6389 if (MemberExpr *member = dyn_cast<MemberExpr>(e)) { 6390 if (member->isArrow()) return false; 6391 6392 // Don't count this as an indirect ownership. 6393 e = member->getBase(); 6394 continue; 6395 } 6396 6397 if (PseudoObjectExpr *pseudo = dyn_cast<PseudoObjectExpr>(e)) { 6398 // Only pay attention to pseudo-objects on property references. 6399 ObjCPropertyRefExpr *pre 6400 = dyn_cast<ObjCPropertyRefExpr>(pseudo->getSyntacticForm() 6401 ->IgnoreParens()); 6402 if (!pre) return false; 6403 if (pre->isImplicitProperty()) return false; 6404 ObjCPropertyDecl *property = pre->getExplicitProperty(); 6405 if (!property->isRetaining() && 6406 !(property->getPropertyIvarDecl() && 6407 property->getPropertyIvarDecl()->getType() 6408 .getObjCLifetime() == Qualifiers::OCL_Strong)) 6409 return false; 6410 6411 owner.Indirect = true; 6412 if (pre->isSuperReceiver()) { 6413 owner.Variable = S.getCurMethodDecl()->getSelfDecl(); 6414 if (!owner.Variable) 6415 return false; 6416 owner.Loc = pre->getLocation(); 6417 owner.Range = pre->getSourceRange(); 6418 return true; 6419 } 6420 e = const_cast<Expr*>(cast<OpaqueValueExpr>(pre->getBase()) 6421 ->getSourceExpr()); 6422 continue; 6423 } 6424 6425 // Array ivars? 6426 6427 return false; 6428 } 6429} 6430 6431namespace { 6432 struct FindCaptureVisitor : EvaluatedExprVisitor<FindCaptureVisitor> { 6433 FindCaptureVisitor(ASTContext &Context, VarDecl *variable) 6434 : EvaluatedExprVisitor<FindCaptureVisitor>(Context), 6435 Variable(variable), Capturer(0) {} 6436 6437 VarDecl *Variable; 6438 Expr *Capturer; 6439 6440 void VisitDeclRefExpr(DeclRefExpr *ref) { 6441 if (ref->getDecl() == Variable && !Capturer) 6442 Capturer = ref; 6443 } 6444 6445 void VisitObjCIvarRefExpr(ObjCIvarRefExpr *ref) { 6446 if (Capturer) return; 6447 Visit(ref->getBase()); 6448 if (Capturer && ref->isFreeIvar()) 6449 Capturer = ref; 6450 } 6451 6452 void VisitBlockExpr(BlockExpr *block) { 6453 // Look inside nested blocks 6454 if (block->getBlockDecl()->capturesVariable(Variable)) 6455 Visit(block->getBlockDecl()->getBody()); 6456 } 6457 6458 void VisitOpaqueValueExpr(OpaqueValueExpr *OVE) { 6459 if (Capturer) return; 6460 if (OVE->getSourceExpr()) 6461 Visit(OVE->getSourceExpr()); 6462 } 6463 }; 6464} 6465 6466/// Check whether the given argument is a block which captures a 6467/// variable. 6468static Expr *findCapturingExpr(Sema &S, Expr *e, RetainCycleOwner &owner) { 6469 assert(owner.Variable && owner.Loc.isValid()); 6470 6471 e = e->IgnoreParenCasts(); 6472 6473 // Look through [^{...} copy] and Block_copy(^{...}). 6474 if (ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(e)) { 6475 Selector Cmd = ME->getSelector(); 6476 if (Cmd.isUnarySelector() && Cmd.getNameForSlot(0) == "copy") { 6477 e = ME->getInstanceReceiver(); 6478 if (!e) 6479 return 0; 6480 e = e->IgnoreParenCasts(); 6481 } 6482 } else if (CallExpr *CE = dyn_cast<CallExpr>(e)) { 6483 if (CE->getNumArgs() == 1) { 6484 FunctionDecl *Fn = dyn_cast_or_null<FunctionDecl>(CE->getCalleeDecl()); 6485 if (Fn) { 6486 const IdentifierInfo *FnI = Fn->getIdentifier(); 6487 if (FnI && FnI->isStr("_Block_copy")) { 6488 e = CE->getArg(0)->IgnoreParenCasts(); 6489 } 6490 } 6491 } 6492 } 6493 6494 BlockExpr *block = dyn_cast<BlockExpr>(e); 6495 if (!block || !block->getBlockDecl()->capturesVariable(owner.Variable)) 6496 return 0; 6497 6498 FindCaptureVisitor visitor(S.Context, owner.Variable); 6499 visitor.Visit(block->getBlockDecl()->getBody()); 6500 return visitor.Capturer; 6501} 6502 6503static void diagnoseRetainCycle(Sema &S, Expr *capturer, 6504 RetainCycleOwner &owner) { 6505 assert(capturer); 6506 assert(owner.Variable && owner.Loc.isValid()); 6507 6508 S.Diag(capturer->getExprLoc(), diag::warn_arc_retain_cycle) 6509 << owner.Variable << capturer->getSourceRange(); 6510 S.Diag(owner.Loc, diag::note_arc_retain_cycle_owner) 6511 << owner.Indirect << owner.Range; 6512} 6513 6514/// Check for a keyword selector that starts with the word 'add' or 6515/// 'set'. 6516static bool isSetterLikeSelector(Selector sel) { 6517 if (sel.isUnarySelector()) return false; 6518 6519 StringRef str = sel.getNameForSlot(0); 6520 while (!str.empty() && str.front() == '_') str = str.substr(1); 6521 if (str.startswith("set")) 6522 str = str.substr(3); 6523 else if (str.startswith("add")) { 6524 // Specially whitelist 'addOperationWithBlock:'. 6525 if (sel.getNumArgs() == 1 && str.startswith("addOperationWithBlock")) 6526 return false; 6527 str = str.substr(3); 6528 } 6529 else 6530 return false; 6531 6532 if (str.empty()) return true; 6533 return !isLowercase(str.front()); 6534} 6535 6536/// Check a message send to see if it's likely to cause a retain cycle. 6537void Sema::checkRetainCycles(ObjCMessageExpr *msg) { 6538 // Only check instance methods whose selector looks like a setter. 6539 if (!msg->isInstanceMessage() || !isSetterLikeSelector(msg->getSelector())) 6540 return; 6541 6542 // Try to find a variable that the receiver is strongly owned by. 6543 RetainCycleOwner owner; 6544 if (msg->getReceiverKind() == ObjCMessageExpr::Instance) { 6545 if (!findRetainCycleOwner(*this, msg->getInstanceReceiver(), owner)) 6546 return; 6547 } else { 6548 assert(msg->getReceiverKind() == ObjCMessageExpr::SuperInstance); 6549 owner.Variable = getCurMethodDecl()->getSelfDecl(); 6550 owner.Loc = msg->getSuperLoc(); 6551 owner.Range = msg->getSuperLoc(); 6552 } 6553 6554 // Check whether the receiver is captured by any of the arguments. 6555 for (unsigned i = 0, e = msg->getNumArgs(); i != e; ++i) 6556 if (Expr *capturer = findCapturingExpr(*this, msg->getArg(i), owner)) 6557 return diagnoseRetainCycle(*this, capturer, owner); 6558} 6559 6560/// Check a property assign to see if it's likely to cause a retain cycle. 6561void Sema::checkRetainCycles(Expr *receiver, Expr *argument) { 6562 RetainCycleOwner owner; 6563 if (!findRetainCycleOwner(*this, receiver, owner)) 6564 return; 6565 6566 if (Expr *capturer = findCapturingExpr(*this, argument, owner)) 6567 diagnoseRetainCycle(*this, capturer, owner); 6568} 6569 6570void Sema::checkRetainCycles(VarDecl *Var, Expr *Init) { 6571 RetainCycleOwner Owner; 6572 if (!considerVariable(Var, /*DeclRefExpr=*/0, Owner)) 6573 return; 6574 6575 // Because we don't have an expression for the variable, we have to set the 6576 // location explicitly here. 6577 Owner.Loc = Var->getLocation(); 6578 Owner.Range = Var->getSourceRange(); 6579 6580 if (Expr *Capturer = findCapturingExpr(*this, Init, Owner)) 6581 diagnoseRetainCycle(*this, Capturer, Owner); 6582} 6583 6584static bool checkUnsafeAssignLiteral(Sema &S, SourceLocation Loc, 6585 Expr *RHS, bool isProperty) { 6586 // Check if RHS is an Objective-C object literal, which also can get 6587 // immediately zapped in a weak reference. Note that we explicitly 6588 // allow ObjCStringLiterals, since those are designed to never really die. 6589 RHS = RHS->IgnoreParenImpCasts(); 6590 6591 // This enum needs to match with the 'select' in 6592 // warn_objc_arc_literal_assign (off-by-1). 6593 Sema::ObjCLiteralKind Kind = S.CheckLiteralKind(RHS); 6594 if (Kind == Sema::LK_String || Kind == Sema::LK_None) 6595 return false; 6596 6597 S.Diag(Loc, diag::warn_arc_literal_assign) 6598 << (unsigned) Kind 6599 << (isProperty ? 0 : 1) 6600 << RHS->getSourceRange(); 6601 6602 return true; 6603} 6604 6605static bool checkUnsafeAssignObject(Sema &S, SourceLocation Loc, 6606 Qualifiers::ObjCLifetime LT, 6607 Expr *RHS, bool isProperty) { 6608 // Strip off any implicit cast added to get to the one ARC-specific. 6609 while (ImplicitCastExpr *cast = dyn_cast<ImplicitCastExpr>(RHS)) { 6610 if (cast->getCastKind() == CK_ARCConsumeObject) { 6611 S.Diag(Loc, diag::warn_arc_retained_assign) 6612 << (LT == Qualifiers::OCL_ExplicitNone) 6613 << (isProperty ? 0 : 1) 6614 << RHS->getSourceRange(); 6615 return true; 6616 } 6617 RHS = cast->getSubExpr(); 6618 } 6619 6620 if (LT == Qualifiers::OCL_Weak && 6621 checkUnsafeAssignLiteral(S, Loc, RHS, isProperty)) 6622 return true; 6623 6624 return false; 6625} 6626 6627bool Sema::checkUnsafeAssigns(SourceLocation Loc, 6628 QualType LHS, Expr *RHS) { 6629 Qualifiers::ObjCLifetime LT = LHS.getObjCLifetime(); 6630 6631 if (LT != Qualifiers::OCL_Weak && LT != Qualifiers::OCL_ExplicitNone) 6632 return false; 6633 6634 if (checkUnsafeAssignObject(*this, Loc, LT, RHS, false)) 6635 return true; 6636 6637 return false; 6638} 6639 6640void Sema::checkUnsafeExprAssigns(SourceLocation Loc, 6641 Expr *LHS, Expr *RHS) { 6642 QualType LHSType; 6643 // PropertyRef on LHS type need be directly obtained from 6644 // its declaration as it has a PsuedoType. 6645 ObjCPropertyRefExpr *PRE 6646 = dyn_cast<ObjCPropertyRefExpr>(LHS->IgnoreParens()); 6647 if (PRE && !PRE->isImplicitProperty()) { 6648 const ObjCPropertyDecl *PD = PRE->getExplicitProperty(); 6649 if (PD) 6650 LHSType = PD->getType(); 6651 } 6652 6653 if (LHSType.isNull()) 6654 LHSType = LHS->getType(); 6655 6656 Qualifiers::ObjCLifetime LT = LHSType.getObjCLifetime(); 6657 6658 if (LT == Qualifiers::OCL_Weak) { 6659 DiagnosticsEngine::Level Level = 6660 Diags.getDiagnosticLevel(diag::warn_arc_repeated_use_of_weak, Loc); 6661 if (Level != DiagnosticsEngine::Ignored) 6662 getCurFunction()->markSafeWeakUse(LHS); 6663 } 6664 6665 if (checkUnsafeAssigns(Loc, LHSType, RHS)) 6666 return; 6667 6668 // FIXME. Check for other life times. 6669 if (LT != Qualifiers::OCL_None) 6670 return; 6671 6672 if (PRE) { 6673 if (PRE->isImplicitProperty()) 6674 return; 6675 const ObjCPropertyDecl *PD = PRE->getExplicitProperty(); 6676 if (!PD) 6677 return; 6678 6679 unsigned Attributes = PD->getPropertyAttributes(); 6680 if (Attributes & ObjCPropertyDecl::OBJC_PR_assign) { 6681 // when 'assign' attribute was not explicitly specified 6682 // by user, ignore it and rely on property type itself 6683 // for lifetime info. 6684 unsigned AsWrittenAttr = PD->getPropertyAttributesAsWritten(); 6685 if (!(AsWrittenAttr & ObjCPropertyDecl::OBJC_PR_assign) && 6686 LHSType->isObjCRetainableType()) 6687 return; 6688 6689 while (ImplicitCastExpr *cast = dyn_cast<ImplicitCastExpr>(RHS)) { 6690 if (cast->getCastKind() == CK_ARCConsumeObject) { 6691 Diag(Loc, diag::warn_arc_retained_property_assign) 6692 << RHS->getSourceRange(); 6693 return; 6694 } 6695 RHS = cast->getSubExpr(); 6696 } 6697 } 6698 else if (Attributes & ObjCPropertyDecl::OBJC_PR_weak) { 6699 if (checkUnsafeAssignObject(*this, Loc, Qualifiers::OCL_Weak, RHS, true)) 6700 return; 6701 } 6702 } 6703} 6704 6705//===--- CHECK: Empty statement body (-Wempty-body) ---------------------===// 6706 6707namespace { 6708bool ShouldDiagnoseEmptyStmtBody(const SourceManager &SourceMgr, 6709 SourceLocation StmtLoc, 6710 const NullStmt *Body) { 6711 // Do not warn if the body is a macro that expands to nothing, e.g: 6712 // 6713 // #define CALL(x) 6714 // if (condition) 6715 // CALL(0); 6716 // 6717 if (Body->hasLeadingEmptyMacro()) 6718 return false; 6719 6720 // Get line numbers of statement and body. 6721 bool StmtLineInvalid; 6722 unsigned StmtLine = SourceMgr.getSpellingLineNumber(StmtLoc, 6723 &StmtLineInvalid); 6724 if (StmtLineInvalid) 6725 return false; 6726 6727 bool BodyLineInvalid; 6728 unsigned BodyLine = SourceMgr.getSpellingLineNumber(Body->getSemiLoc(), 6729 &BodyLineInvalid); 6730 if (BodyLineInvalid) 6731 return false; 6732 6733 // Warn if null statement and body are on the same line. 6734 if (StmtLine != BodyLine) 6735 return false; 6736 6737 return true; 6738} 6739} // Unnamed namespace 6740 6741void Sema::DiagnoseEmptyStmtBody(SourceLocation StmtLoc, 6742 const Stmt *Body, 6743 unsigned DiagID) { 6744 // Since this is a syntactic check, don't emit diagnostic for template 6745 // instantiations, this just adds noise. 6746 if (CurrentInstantiationScope) 6747 return; 6748 6749 // The body should be a null statement. 6750 const NullStmt *NBody = dyn_cast<NullStmt>(Body); 6751 if (!NBody) 6752 return; 6753 6754 // Do the usual checks. 6755 if (!ShouldDiagnoseEmptyStmtBody(SourceMgr, StmtLoc, NBody)) 6756 return; 6757 6758 Diag(NBody->getSemiLoc(), DiagID); 6759 Diag(NBody->getSemiLoc(), diag::note_empty_body_on_separate_line); 6760} 6761 6762void Sema::DiagnoseEmptyLoopBody(const Stmt *S, 6763 const Stmt *PossibleBody) { 6764 assert(!CurrentInstantiationScope); // Ensured by caller 6765 6766 SourceLocation StmtLoc; 6767 const Stmt *Body; 6768 unsigned DiagID; 6769 if (const ForStmt *FS = dyn_cast<ForStmt>(S)) { 6770 StmtLoc = FS->getRParenLoc(); 6771 Body = FS->getBody(); 6772 DiagID = diag::warn_empty_for_body; 6773 } else if (const WhileStmt *WS = dyn_cast<WhileStmt>(S)) { 6774 StmtLoc = WS->getCond()->getSourceRange().getEnd(); 6775 Body = WS->getBody(); 6776 DiagID = diag::warn_empty_while_body; 6777 } else 6778 return; // Neither `for' nor `while'. 6779 6780 // The body should be a null statement. 6781 const NullStmt *NBody = dyn_cast<NullStmt>(Body); 6782 if (!NBody) 6783 return; 6784 6785 // Skip expensive checks if diagnostic is disabled. 6786 if (Diags.getDiagnosticLevel(DiagID, NBody->getSemiLoc()) == 6787 DiagnosticsEngine::Ignored) 6788 return; 6789 6790 // Do the usual checks. 6791 if (!ShouldDiagnoseEmptyStmtBody(SourceMgr, StmtLoc, NBody)) 6792 return; 6793 6794 // `for(...);' and `while(...);' are popular idioms, so in order to keep 6795 // noise level low, emit diagnostics only if for/while is followed by a 6796 // CompoundStmt, e.g.: 6797 // for (int i = 0; i < n; i++); 6798 // { 6799 // a(i); 6800 // } 6801 // or if for/while is followed by a statement with more indentation 6802 // than for/while itself: 6803 // for (int i = 0; i < n; i++); 6804 // a(i); 6805 bool ProbableTypo = isa<CompoundStmt>(PossibleBody); 6806 if (!ProbableTypo) { 6807 bool BodyColInvalid; 6808 unsigned BodyCol = SourceMgr.getPresumedColumnNumber( 6809 PossibleBody->getLocStart(), 6810 &BodyColInvalid); 6811 if (BodyColInvalid) 6812 return; 6813 6814 bool StmtColInvalid; 6815 unsigned StmtCol = SourceMgr.getPresumedColumnNumber( 6816 S->getLocStart(), 6817 &StmtColInvalid); 6818 if (StmtColInvalid) 6819 return; 6820 6821 if (BodyCol > StmtCol) 6822 ProbableTypo = true; 6823 } 6824 6825 if (ProbableTypo) { 6826 Diag(NBody->getSemiLoc(), DiagID); 6827 Diag(NBody->getSemiLoc(), diag::note_empty_body_on_separate_line); 6828 } 6829} 6830 6831//===--- Layout compatibility ----------------------------------------------// 6832 6833namespace { 6834 6835bool isLayoutCompatible(ASTContext &C, QualType T1, QualType T2); 6836 6837/// \brief Check if two enumeration types are layout-compatible. 6838bool isLayoutCompatible(ASTContext &C, EnumDecl *ED1, EnumDecl *ED2) { 6839 // C++11 [dcl.enum] p8: 6840 // Two enumeration types are layout-compatible if they have the same 6841 // underlying type. 6842 return ED1->isComplete() && ED2->isComplete() && 6843 C.hasSameType(ED1->getIntegerType(), ED2->getIntegerType()); 6844} 6845 6846/// \brief Check if two fields are layout-compatible. 6847bool isLayoutCompatible(ASTContext &C, FieldDecl *Field1, FieldDecl *Field2) { 6848 if (!isLayoutCompatible(C, Field1->getType(), Field2->getType())) 6849 return false; 6850 6851 if (Field1->isBitField() != Field2->isBitField()) 6852 return false; 6853 6854 if (Field1->isBitField()) { 6855 // Make sure that the bit-fields are the same length. 6856 unsigned Bits1 = Field1->getBitWidthValue(C); 6857 unsigned Bits2 = Field2->getBitWidthValue(C); 6858 6859 if (Bits1 != Bits2) 6860 return false; 6861 } 6862 6863 return true; 6864} 6865 6866/// \brief Check if two standard-layout structs are layout-compatible. 6867/// (C++11 [class.mem] p17) 6868bool isLayoutCompatibleStruct(ASTContext &C, 6869 RecordDecl *RD1, 6870 RecordDecl *RD2) { 6871 // If both records are C++ classes, check that base classes match. 6872 if (const CXXRecordDecl *D1CXX = dyn_cast<CXXRecordDecl>(RD1)) { 6873 // If one of records is a CXXRecordDecl we are in C++ mode, 6874 // thus the other one is a CXXRecordDecl, too. 6875 const CXXRecordDecl *D2CXX = cast<CXXRecordDecl>(RD2); 6876 // Check number of base classes. 6877 if (D1CXX->getNumBases() != D2CXX->getNumBases()) 6878 return false; 6879 6880 // Check the base classes. 6881 for (CXXRecordDecl::base_class_const_iterator 6882 Base1 = D1CXX->bases_begin(), 6883 BaseEnd1 = D1CXX->bases_end(), 6884 Base2 = D2CXX->bases_begin(); 6885 Base1 != BaseEnd1; 6886 ++Base1, ++Base2) { 6887 if (!isLayoutCompatible(C, Base1->getType(), Base2->getType())) 6888 return false; 6889 } 6890 } else if (const CXXRecordDecl *D2CXX = dyn_cast<CXXRecordDecl>(RD2)) { 6891 // If only RD2 is a C++ class, it should have zero base classes. 6892 if (D2CXX->getNumBases() > 0) 6893 return false; 6894 } 6895 6896 // Check the fields. 6897 RecordDecl::field_iterator Field2 = RD2->field_begin(), 6898 Field2End = RD2->field_end(), 6899 Field1 = RD1->field_begin(), 6900 Field1End = RD1->field_end(); 6901 for ( ; Field1 != Field1End && Field2 != Field2End; ++Field1, ++Field2) { 6902 if (!isLayoutCompatible(C, *Field1, *Field2)) 6903 return false; 6904 } 6905 if (Field1 != Field1End || Field2 != Field2End) 6906 return false; 6907 6908 return true; 6909} 6910 6911/// \brief Check if two standard-layout unions are layout-compatible. 6912/// (C++11 [class.mem] p18) 6913bool isLayoutCompatibleUnion(ASTContext &C, 6914 RecordDecl *RD1, 6915 RecordDecl *RD2) { 6916 llvm::SmallPtrSet<FieldDecl *, 8> UnmatchedFields; 6917 for (RecordDecl::field_iterator Field2 = RD2->field_begin(), 6918 Field2End = RD2->field_end(); 6919 Field2 != Field2End; ++Field2) { 6920 UnmatchedFields.insert(*Field2); 6921 } 6922 6923 for (RecordDecl::field_iterator Field1 = RD1->field_begin(), 6924 Field1End = RD1->field_end(); 6925 Field1 != Field1End; ++Field1) { 6926 llvm::SmallPtrSet<FieldDecl *, 8>::iterator 6927 I = UnmatchedFields.begin(), 6928 E = UnmatchedFields.end(); 6929 6930 for ( ; I != E; ++I) { 6931 if (isLayoutCompatible(C, *Field1, *I)) { 6932 bool Result = UnmatchedFields.erase(*I); 6933 (void) Result; 6934 assert(Result); 6935 break; 6936 } 6937 } 6938 if (I == E) 6939 return false; 6940 } 6941 6942 return UnmatchedFields.empty(); 6943} 6944 6945bool isLayoutCompatible(ASTContext &C, RecordDecl *RD1, RecordDecl *RD2) { 6946 if (RD1->isUnion() != RD2->isUnion()) 6947 return false; 6948 6949 if (RD1->isUnion()) 6950 return isLayoutCompatibleUnion(C, RD1, RD2); 6951 else 6952 return isLayoutCompatibleStruct(C, RD1, RD2); 6953} 6954 6955/// \brief Check if two types are layout-compatible in C++11 sense. 6956bool isLayoutCompatible(ASTContext &C, QualType T1, QualType T2) { 6957 if (T1.isNull() || T2.isNull()) 6958 return false; 6959 6960 // C++11 [basic.types] p11: 6961 // If two types T1 and T2 are the same type, then T1 and T2 are 6962 // layout-compatible types. 6963 if (C.hasSameType(T1, T2)) 6964 return true; 6965 6966 T1 = T1.getCanonicalType().getUnqualifiedType(); 6967 T2 = T2.getCanonicalType().getUnqualifiedType(); 6968 6969 const Type::TypeClass TC1 = T1->getTypeClass(); 6970 const Type::TypeClass TC2 = T2->getTypeClass(); 6971 6972 if (TC1 != TC2) 6973 return false; 6974 6975 if (TC1 == Type::Enum) { 6976 return isLayoutCompatible(C, 6977 cast<EnumType>(T1)->getDecl(), 6978 cast<EnumType>(T2)->getDecl()); 6979 } else if (TC1 == Type::Record) { 6980 if (!T1->isStandardLayoutType() || !T2->isStandardLayoutType()) 6981 return false; 6982 6983 return isLayoutCompatible(C, 6984 cast<RecordType>(T1)->getDecl(), 6985 cast<RecordType>(T2)->getDecl()); 6986 } 6987 6988 return false; 6989} 6990} 6991 6992//===--- CHECK: pointer_with_type_tag attribute: datatypes should match ----// 6993 6994namespace { 6995/// \brief Given a type tag expression find the type tag itself. 6996/// 6997/// \param TypeExpr Type tag expression, as it appears in user's code. 6998/// 6999/// \param VD Declaration of an identifier that appears in a type tag. 7000/// 7001/// \param MagicValue Type tag magic value. 7002bool FindTypeTagExpr(const Expr *TypeExpr, const ASTContext &Ctx, 7003 const ValueDecl **VD, uint64_t *MagicValue) { 7004 while(true) { 7005 if (!TypeExpr) 7006 return false; 7007 7008 TypeExpr = TypeExpr->IgnoreParenImpCasts()->IgnoreParenCasts(); 7009 7010 switch (TypeExpr->getStmtClass()) { 7011 case Stmt::UnaryOperatorClass: { 7012 const UnaryOperator *UO = cast<UnaryOperator>(TypeExpr); 7013 if (UO->getOpcode() == UO_AddrOf || UO->getOpcode() == UO_Deref) { 7014 TypeExpr = UO->getSubExpr(); 7015 continue; 7016 } 7017 return false; 7018 } 7019 7020 case Stmt::DeclRefExprClass: { 7021 const DeclRefExpr *DRE = cast<DeclRefExpr>(TypeExpr); 7022 *VD = DRE->getDecl(); 7023 return true; 7024 } 7025 7026 case Stmt::IntegerLiteralClass: { 7027 const IntegerLiteral *IL = cast<IntegerLiteral>(TypeExpr); 7028 llvm::APInt MagicValueAPInt = IL->getValue(); 7029 if (MagicValueAPInt.getActiveBits() <= 64) { 7030 *MagicValue = MagicValueAPInt.getZExtValue(); 7031 return true; 7032 } else 7033 return false; 7034 } 7035 7036 case Stmt::BinaryConditionalOperatorClass: 7037 case Stmt::ConditionalOperatorClass: { 7038 const AbstractConditionalOperator *ACO = 7039 cast<AbstractConditionalOperator>(TypeExpr); 7040 bool Result; 7041 if (ACO->getCond()->EvaluateAsBooleanCondition(Result, Ctx)) { 7042 if (Result) 7043 TypeExpr = ACO->getTrueExpr(); 7044 else 7045 TypeExpr = ACO->getFalseExpr(); 7046 continue; 7047 } 7048 return false; 7049 } 7050 7051 case Stmt::BinaryOperatorClass: { 7052 const BinaryOperator *BO = cast<BinaryOperator>(TypeExpr); 7053 if (BO->getOpcode() == BO_Comma) { 7054 TypeExpr = BO->getRHS(); 7055 continue; 7056 } 7057 return false; 7058 } 7059 7060 default: 7061 return false; 7062 } 7063 } 7064} 7065 7066/// \brief Retrieve the C type corresponding to type tag TypeExpr. 7067/// 7068/// \param TypeExpr Expression that specifies a type tag. 7069/// 7070/// \param MagicValues Registered magic values. 7071/// 7072/// \param FoundWrongKind Set to true if a type tag was found, but of a wrong 7073/// kind. 7074/// 7075/// \param TypeInfo Information about the corresponding C type. 7076/// 7077/// \returns true if the corresponding C type was found. 7078bool GetMatchingCType( 7079 const IdentifierInfo *ArgumentKind, 7080 const Expr *TypeExpr, const ASTContext &Ctx, 7081 const llvm::DenseMap<Sema::TypeTagMagicValue, 7082 Sema::TypeTagData> *MagicValues, 7083 bool &FoundWrongKind, 7084 Sema::TypeTagData &TypeInfo) { 7085 FoundWrongKind = false; 7086 7087 // Variable declaration that has type_tag_for_datatype attribute. 7088 const ValueDecl *VD = NULL; 7089 7090 uint64_t MagicValue; 7091 7092 if (!FindTypeTagExpr(TypeExpr, Ctx, &VD, &MagicValue)) 7093 return false; 7094 7095 if (VD) { 7096 for (specific_attr_iterator<TypeTagForDatatypeAttr> 7097 I = VD->specific_attr_begin<TypeTagForDatatypeAttr>(), 7098 E = VD->specific_attr_end<TypeTagForDatatypeAttr>(); 7099 I != E; ++I) { 7100 if (I->getArgumentKind() != ArgumentKind) { 7101 FoundWrongKind = true; 7102 return false; 7103 } 7104 TypeInfo.Type = I->getMatchingCType(); 7105 TypeInfo.LayoutCompatible = I->getLayoutCompatible(); 7106 TypeInfo.MustBeNull = I->getMustBeNull(); 7107 return true; 7108 } 7109 return false; 7110 } 7111 7112 if (!MagicValues) 7113 return false; 7114 7115 llvm::DenseMap<Sema::TypeTagMagicValue, 7116 Sema::TypeTagData>::const_iterator I = 7117 MagicValues->find(std::make_pair(ArgumentKind, MagicValue)); 7118 if (I == MagicValues->end()) 7119 return false; 7120 7121 TypeInfo = I->second; 7122 return true; 7123} 7124} // unnamed namespace 7125 7126void Sema::RegisterTypeTagForDatatype(const IdentifierInfo *ArgumentKind, 7127 uint64_t MagicValue, QualType Type, 7128 bool LayoutCompatible, 7129 bool MustBeNull) { 7130 if (!TypeTagForDatatypeMagicValues) 7131 TypeTagForDatatypeMagicValues.reset( 7132 new llvm::DenseMap<TypeTagMagicValue, TypeTagData>); 7133 7134 TypeTagMagicValue Magic(ArgumentKind, MagicValue); 7135 (*TypeTagForDatatypeMagicValues)[Magic] = 7136 TypeTagData(Type, LayoutCompatible, MustBeNull); 7137} 7138 7139namespace { 7140bool IsSameCharType(QualType T1, QualType T2) { 7141 const BuiltinType *BT1 = T1->getAs<BuiltinType>(); 7142 if (!BT1) 7143 return false; 7144 7145 const BuiltinType *BT2 = T2->getAs<BuiltinType>(); 7146 if (!BT2) 7147 return false; 7148 7149 BuiltinType::Kind T1Kind = BT1->getKind(); 7150 BuiltinType::Kind T2Kind = BT2->getKind(); 7151 7152 return (T1Kind == BuiltinType::SChar && T2Kind == BuiltinType::Char_S) || 7153 (T1Kind == BuiltinType::UChar && T2Kind == BuiltinType::Char_U) || 7154 (T1Kind == BuiltinType::Char_U && T2Kind == BuiltinType::UChar) || 7155 (T1Kind == BuiltinType::Char_S && T2Kind == BuiltinType::SChar); 7156} 7157} // unnamed namespace 7158 7159void Sema::CheckArgumentWithTypeTag(const ArgumentWithTypeTagAttr *Attr, 7160 const Expr * const *ExprArgs) { 7161 const IdentifierInfo *ArgumentKind = Attr->getArgumentKind(); 7162 bool IsPointerAttr = Attr->getIsPointer(); 7163 7164 const Expr *TypeTagExpr = ExprArgs[Attr->getTypeTagIdx()]; 7165 bool FoundWrongKind; 7166 TypeTagData TypeInfo; 7167 if (!GetMatchingCType(ArgumentKind, TypeTagExpr, Context, 7168 TypeTagForDatatypeMagicValues.get(), 7169 FoundWrongKind, TypeInfo)) { 7170 if (FoundWrongKind) 7171 Diag(TypeTagExpr->getExprLoc(), 7172 diag::warn_type_tag_for_datatype_wrong_kind) 7173 << TypeTagExpr->getSourceRange(); 7174 return; 7175 } 7176 7177 const Expr *ArgumentExpr = ExprArgs[Attr->getArgumentIdx()]; 7178 if (IsPointerAttr) { 7179 // Skip implicit cast of pointer to `void *' (as a function argument). 7180 if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(ArgumentExpr)) 7181 if (ICE->getType()->isVoidPointerType() && 7182 ICE->getCastKind() == CK_BitCast) 7183 ArgumentExpr = ICE->getSubExpr(); 7184 } 7185 QualType ArgumentType = ArgumentExpr->getType(); 7186 7187 // Passing a `void*' pointer shouldn't trigger a warning. 7188 if (IsPointerAttr && ArgumentType->isVoidPointerType()) 7189 return; 7190 7191 if (TypeInfo.MustBeNull) { 7192 // Type tag with matching void type requires a null pointer. 7193 if (!ArgumentExpr->isNullPointerConstant(Context, 7194 Expr::NPC_ValueDependentIsNotNull)) { 7195 Diag(ArgumentExpr->getExprLoc(), 7196 diag::warn_type_safety_null_pointer_required) 7197 << ArgumentKind->getName() 7198 << ArgumentExpr->getSourceRange() 7199 << TypeTagExpr->getSourceRange(); 7200 } 7201 return; 7202 } 7203 7204 QualType RequiredType = TypeInfo.Type; 7205 if (IsPointerAttr) 7206 RequiredType = Context.getPointerType(RequiredType); 7207 7208 bool mismatch = false; 7209 if (!TypeInfo.LayoutCompatible) { 7210 mismatch = !Context.hasSameType(ArgumentType, RequiredType); 7211 7212 // C++11 [basic.fundamental] p1: 7213 // Plain char, signed char, and unsigned char are three distinct types. 7214 // 7215 // But we treat plain `char' as equivalent to `signed char' or `unsigned 7216 // char' depending on the current char signedness mode. 7217 if (mismatch) 7218 if ((IsPointerAttr && IsSameCharType(ArgumentType->getPointeeType(), 7219 RequiredType->getPointeeType())) || 7220 (!IsPointerAttr && IsSameCharType(ArgumentType, RequiredType))) 7221 mismatch = false; 7222 } else 7223 if (IsPointerAttr) 7224 mismatch = !isLayoutCompatible(Context, 7225 ArgumentType->getPointeeType(), 7226 RequiredType->getPointeeType()); 7227 else 7228 mismatch = !isLayoutCompatible(Context, ArgumentType, RequiredType); 7229 7230 if (mismatch) 7231 Diag(ArgumentExpr->getExprLoc(), diag::warn_type_safety_type_mismatch) 7232 << ArgumentType << ArgumentKind->getName() 7233 << TypeInfo.LayoutCompatible << RequiredType 7234 << ArgumentExpr->getSourceRange() 7235 << TypeTagExpr->getSourceRange(); 7236} 7237