SemaChecking.cpp revision 9325eaf08fcccbc0d038e703f570c64daacdaa31
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/Sema.h" 16#include "clang/Analysis/Analyses/FormatString.h" 17#include "clang/AST/ASTContext.h" 18#include "clang/AST/CharUnits.h" 19#include "clang/AST/DeclObjC.h" 20#include "clang/AST/ExprCXX.h" 21#include "clang/AST/ExprObjC.h" 22#include "clang/AST/DeclObjC.h" 23#include "clang/AST/StmtCXX.h" 24#include "clang/AST/StmtObjC.h" 25#include "clang/Lex/LiteralSupport.h" 26#include "clang/Lex/Preprocessor.h" 27#include "llvm/ADT/BitVector.h" 28#include "llvm/ADT/STLExtras.h" 29#include "llvm/Support/raw_ostream.h" 30#include "clang/Basic/TargetBuiltins.h" 31#include "clang/Basic/TargetInfo.h" 32#include <limits> 33using namespace clang; 34 35/// getLocationOfStringLiteralByte - Return a source location that points to the 36/// specified byte of the specified string literal. 37/// 38/// Strings are amazingly complex. They can be formed from multiple tokens and 39/// can have escape sequences in them in addition to the usual trigraph and 40/// escaped newline business. This routine handles this complexity. 41/// 42SourceLocation Sema::getLocationOfStringLiteralByte(const StringLiteral *SL, 43 unsigned ByteNo) const { 44 assert(!SL->isWide() && "This doesn't work for wide strings yet"); 45 46 // Loop over all of the tokens in this string until we find the one that 47 // contains the byte we're looking for. 48 unsigned TokNo = 0; 49 while (1) { 50 assert(TokNo < SL->getNumConcatenated() && "Invalid byte number!"); 51 SourceLocation StrTokLoc = SL->getStrTokenLoc(TokNo); 52 53 // Get the spelling of the string so that we can get the data that makes up 54 // the string literal, not the identifier for the macro it is potentially 55 // expanded through. 56 SourceLocation StrTokSpellingLoc = SourceMgr.getSpellingLoc(StrTokLoc); 57 58 // Re-lex the token to get its length and original spelling. 59 std::pair<FileID, unsigned> LocInfo = 60 SourceMgr.getDecomposedLoc(StrTokSpellingLoc); 61 bool Invalid = false; 62 llvm::StringRef Buffer = SourceMgr.getBufferData(LocInfo.first, &Invalid); 63 if (Invalid) 64 return StrTokSpellingLoc; 65 66 const char *StrData = Buffer.data()+LocInfo.second; 67 68 // Create a langops struct and enable trigraphs. This is sufficient for 69 // relexing tokens. 70 LangOptions LangOpts; 71 LangOpts.Trigraphs = true; 72 73 // Create a lexer starting at the beginning of this token. 74 Lexer TheLexer(StrTokSpellingLoc, LangOpts, Buffer.begin(), StrData, 75 Buffer.end()); 76 Token TheTok; 77 TheLexer.LexFromRawLexer(TheTok); 78 79 // Use the StringLiteralParser to compute the length of the string in bytes. 80 StringLiteralParser SLP(&TheTok, 1, PP, /*Complain=*/false); 81 unsigned TokNumBytes = SLP.GetStringLength(); 82 83 // If the byte is in this token, return the location of the byte. 84 if (ByteNo < TokNumBytes || 85 (ByteNo == TokNumBytes && TokNo == SL->getNumConcatenated())) { 86 unsigned Offset = 87 StringLiteralParser::getOffsetOfStringByte(TheTok, ByteNo, PP, 88 /*Complain=*/false); 89 90 // Now that we know the offset of the token in the spelling, use the 91 // preprocessor to get the offset in the original source. 92 return PP.AdvanceToTokenCharacter(StrTokLoc, Offset); 93 } 94 95 // Move to the next string token. 96 ++TokNo; 97 ByteNo -= TokNumBytes; 98 } 99} 100 101/// CheckablePrintfAttr - does a function call have a "printf" attribute 102/// and arguments that merit checking? 103bool Sema::CheckablePrintfAttr(const FormatAttr *Format, CallExpr *TheCall) { 104 if (Format->getType() == "printf") return true; 105 if (Format->getType() == "printf0") { 106 // printf0 allows null "format" string; if so don't check format/args 107 unsigned format_idx = Format->getFormatIdx() - 1; 108 // Does the index refer to the implicit object argument? 109 if (isa<CXXMemberCallExpr>(TheCall)) { 110 if (format_idx == 0) 111 return false; 112 --format_idx; 113 } 114 if (format_idx < TheCall->getNumArgs()) { 115 Expr *Format = TheCall->getArg(format_idx)->IgnoreParenCasts(); 116 if (!Format->isNullPointerConstant(Context, 117 Expr::NPC_ValueDependentIsNull)) 118 return true; 119 } 120 } 121 return false; 122} 123 124ExprResult 125Sema::CheckBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) { 126 ExprResult TheCallResult(Owned(TheCall)); 127 128 switch (BuiltinID) { 129 case Builtin::BI__builtin___CFStringMakeConstantString: 130 assert(TheCall->getNumArgs() == 1 && 131 "Wrong # arguments to builtin CFStringMakeConstantString"); 132 if (CheckObjCString(TheCall->getArg(0))) 133 return ExprError(); 134 break; 135 case Builtin::BI__builtin_stdarg_start: 136 case Builtin::BI__builtin_va_start: 137 if (SemaBuiltinVAStart(TheCall)) 138 return ExprError(); 139 break; 140 case Builtin::BI__builtin_isgreater: 141 case Builtin::BI__builtin_isgreaterequal: 142 case Builtin::BI__builtin_isless: 143 case Builtin::BI__builtin_islessequal: 144 case Builtin::BI__builtin_islessgreater: 145 case Builtin::BI__builtin_isunordered: 146 if (SemaBuiltinUnorderedCompare(TheCall)) 147 return ExprError(); 148 break; 149 case Builtin::BI__builtin_fpclassify: 150 if (SemaBuiltinFPClassification(TheCall, 6)) 151 return ExprError(); 152 break; 153 case Builtin::BI__builtin_isfinite: 154 case Builtin::BI__builtin_isinf: 155 case Builtin::BI__builtin_isinf_sign: 156 case Builtin::BI__builtin_isnan: 157 case Builtin::BI__builtin_isnormal: 158 if (SemaBuiltinFPClassification(TheCall, 1)) 159 return ExprError(); 160 break; 161 case Builtin::BI__builtin_return_address: 162 case Builtin::BI__builtin_frame_address: { 163 llvm::APSInt Result; 164 if (SemaBuiltinConstantArg(TheCall, 0, Result)) 165 return ExprError(); 166 break; 167 } 168 case Builtin::BI__builtin_eh_return_data_regno: { 169 llvm::APSInt Result; 170 if (SemaBuiltinConstantArg(TheCall, 0, Result)) 171 return ExprError(); 172 break; 173 } 174 case Builtin::BI__builtin_shufflevector: 175 return SemaBuiltinShuffleVector(TheCall); 176 // TheCall will be freed by the smart pointer here, but that's fine, since 177 // SemaBuiltinShuffleVector guts it, but then doesn't release it. 178 case Builtin::BI__builtin_prefetch: 179 if (SemaBuiltinPrefetch(TheCall)) 180 return ExprError(); 181 break; 182 case Builtin::BI__builtin_object_size: 183 if (SemaBuiltinObjectSize(TheCall)) 184 return ExprError(); 185 break; 186 case Builtin::BI__builtin_longjmp: 187 if (SemaBuiltinLongjmp(TheCall)) 188 return ExprError(); 189 break; 190 case Builtin::BI__sync_fetch_and_add: 191 case Builtin::BI__sync_fetch_and_sub: 192 case Builtin::BI__sync_fetch_and_or: 193 case Builtin::BI__sync_fetch_and_and: 194 case Builtin::BI__sync_fetch_and_xor: 195 case Builtin::BI__sync_add_and_fetch: 196 case Builtin::BI__sync_sub_and_fetch: 197 case Builtin::BI__sync_and_and_fetch: 198 case Builtin::BI__sync_or_and_fetch: 199 case Builtin::BI__sync_xor_and_fetch: 200 case Builtin::BI__sync_val_compare_and_swap: 201 case Builtin::BI__sync_bool_compare_and_swap: 202 case Builtin::BI__sync_lock_test_and_set: 203 case Builtin::BI__sync_lock_release: 204 return SemaBuiltinAtomicOverloaded(move(TheCallResult)); 205 } 206 207 // Since the target specific builtins for each arch overlap, only check those 208 // of the arch we are compiling for. 209 if (BuiltinID >= Builtin::FirstTSBuiltin) { 210 switch (Context.Target.getTriple().getArch()) { 211 case llvm::Triple::arm: 212 case llvm::Triple::thumb: 213 if (CheckARMBuiltinFunctionCall(BuiltinID, TheCall)) 214 return ExprError(); 215 break; 216 case llvm::Triple::x86: 217 case llvm::Triple::x86_64: 218 if (CheckX86BuiltinFunctionCall(BuiltinID, TheCall)) 219 return ExprError(); 220 break; 221 default: 222 break; 223 } 224 } 225 226 return move(TheCallResult); 227} 228 229bool Sema::CheckX86BuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) { 230 switch (BuiltinID) { 231 case X86::BI__builtin_ia32_palignr128: 232 case X86::BI__builtin_ia32_palignr: { 233 llvm::APSInt Result; 234 if (SemaBuiltinConstantArg(TheCall, 2, Result)) 235 return true; 236 break; 237 } 238 } 239 return false; 240} 241 242// Get the valid immediate range for the specified NEON type code. 243static unsigned RFT(unsigned t, bool shift = false) { 244 bool quad = t & 0x10; 245 246 switch (t & 0x7) { 247 case 0: // i8 248 return shift ? 7 : (8 << (int)quad) - 1; 249 case 1: // i16 250 return shift ? 15 : (4 << (int)quad) - 1; 251 case 2: // i32 252 return shift ? 31 : (2 << (int)quad) - 1; 253 case 3: // i64 254 return shift ? 63 : (1 << (int)quad) - 1; 255 case 4: // f32 256 assert(!shift && "cannot shift float types!"); 257 return (2 << (int)quad) - 1; 258 case 5: // poly8 259 assert(!shift && "cannot shift polynomial types!"); 260 return (8 << (int)quad) - 1; 261 case 6: // poly16 262 assert(!shift && "cannot shift polynomial types!"); 263 return (4 << (int)quad) - 1; 264 case 7: // float16 265 assert(!shift && "cannot shift float types!"); 266 return (4 << (int)quad) - 1; 267 } 268 return 0; 269} 270 271bool Sema::CheckARMBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) { 272 llvm::APSInt Result; 273 274 unsigned mask = 0; 275 unsigned TV = 0; 276 switch (BuiltinID) { 277#define GET_NEON_OVERLOAD_CHECK 278#include "clang/Basic/arm_neon.inc" 279#undef GET_NEON_OVERLOAD_CHECK 280 } 281 282 // For NEON intrinsics which are overloaded on vector element type, validate 283 // the immediate which specifies which variant to emit. 284 if (mask) { 285 unsigned ArgNo = TheCall->getNumArgs()-1; 286 if (SemaBuiltinConstantArg(TheCall, ArgNo, Result)) 287 return true; 288 289 TV = Result.getLimitedValue(32); 290 if ((TV > 31) || (mask & (1 << TV)) == 0) 291 return Diag(TheCall->getLocStart(), diag::err_invalid_neon_type_code) 292 << TheCall->getArg(ArgNo)->getSourceRange(); 293 } 294 295 // For NEON intrinsics which take an immediate value as part of the 296 // instruction, range check them here. 297 unsigned i = 0, l = 0, u = 0; 298 switch (BuiltinID) { 299 default: return false; 300 case ARM::BI__builtin_arm_ssat: i = 1; l = 1; u = 31; break; 301 case ARM::BI__builtin_arm_usat: i = 1; u = 31; break; 302 case ARM::BI__builtin_arm_vcvtr_f: 303 case ARM::BI__builtin_arm_vcvtr_d: i = 1; u = 1; break; 304#define GET_NEON_IMMEDIATE_CHECK 305#include "clang/Basic/arm_neon.inc" 306#undef GET_NEON_IMMEDIATE_CHECK 307 }; 308 309 // Check that the immediate argument is actually a constant. 310 if (SemaBuiltinConstantArg(TheCall, i, Result)) 311 return true; 312 313 // Range check against the upper/lower values for this isntruction. 314 unsigned Val = Result.getZExtValue(); 315 if (Val < l || Val > (u + l)) 316 return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range) 317 << l << u+l << TheCall->getArg(i)->getSourceRange(); 318 319 // FIXME: VFP Intrinsics should error if VFP not present. 320 return false; 321} 322 323/// CheckFunctionCall - Check a direct function call for various correctness 324/// and safety properties not strictly enforced by the C type system. 325bool Sema::CheckFunctionCall(FunctionDecl *FDecl, CallExpr *TheCall) { 326 // Get the IdentifierInfo* for the called function. 327 IdentifierInfo *FnInfo = FDecl->getIdentifier(); 328 329 // None of the checks below are needed for functions that don't have 330 // simple names (e.g., C++ conversion functions). 331 if (!FnInfo) 332 return false; 333 334 // FIXME: This mechanism should be abstracted to be less fragile and 335 // more efficient. For example, just map function ids to custom 336 // handlers. 337 338 // Printf checking. 339 if (const FormatAttr *Format = FDecl->getAttr<FormatAttr>()) { 340 const bool b = Format->getType() == "scanf"; 341 if (b || CheckablePrintfAttr(Format, TheCall)) { 342 bool HasVAListArg = Format->getFirstArg() == 0; 343 CheckPrintfScanfArguments(TheCall, HasVAListArg, 344 Format->getFormatIdx() - 1, 345 HasVAListArg ? 0 : Format->getFirstArg() - 1, 346 !b); 347 } 348 } 349 350 specific_attr_iterator<NonNullAttr> 351 i = FDecl->specific_attr_begin<NonNullAttr>(), 352 e = FDecl->specific_attr_end<NonNullAttr>(); 353 354 for (; i != e; ++i) 355 CheckNonNullArguments(*i, TheCall); 356 357 return false; 358} 359 360bool Sema::CheckBlockCall(NamedDecl *NDecl, CallExpr *TheCall) { 361 // Printf checking. 362 const FormatAttr *Format = NDecl->getAttr<FormatAttr>(); 363 if (!Format) 364 return false; 365 366 const VarDecl *V = dyn_cast<VarDecl>(NDecl); 367 if (!V) 368 return false; 369 370 QualType Ty = V->getType(); 371 if (!Ty->isBlockPointerType()) 372 return false; 373 374 const bool b = Format->getType() == "scanf"; 375 if (!b && !CheckablePrintfAttr(Format, TheCall)) 376 return false; 377 378 bool HasVAListArg = Format->getFirstArg() == 0; 379 CheckPrintfScanfArguments(TheCall, HasVAListArg, Format->getFormatIdx() - 1, 380 HasVAListArg ? 0 : Format->getFirstArg() - 1, !b); 381 382 return false; 383} 384 385/// SemaBuiltinAtomicOverloaded - We have a call to a function like 386/// __sync_fetch_and_add, which is an overloaded function based on the pointer 387/// type of its first argument. The main ActOnCallExpr routines have already 388/// promoted the types of arguments because all of these calls are prototyped as 389/// void(...). 390/// 391/// This function goes through and does final semantic checking for these 392/// builtins, 393ExprResult 394Sema::SemaBuiltinAtomicOverloaded(ExprResult TheCallResult) { 395 CallExpr *TheCall = (CallExpr *)TheCallResult.get(); 396 DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts()); 397 FunctionDecl *FDecl = cast<FunctionDecl>(DRE->getDecl()); 398 399 // Ensure that we have at least one argument to do type inference from. 400 if (TheCall->getNumArgs() < 1) { 401 Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args_at_least) 402 << 0 << 1 << TheCall->getNumArgs() 403 << TheCall->getCallee()->getSourceRange(); 404 return ExprError(); 405 } 406 407 // Inspect the first argument of the atomic builtin. This should always be 408 // a pointer type, whose element is an integral scalar or pointer type. 409 // Because it is a pointer type, we don't have to worry about any implicit 410 // casts here. 411 // FIXME: We don't allow floating point scalars as input. 412 Expr *FirstArg = TheCall->getArg(0); 413 if (!FirstArg->getType()->isPointerType()) { 414 Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer) 415 << FirstArg->getType() << FirstArg->getSourceRange(); 416 return ExprError(); 417 } 418 419 QualType ValType = 420 FirstArg->getType()->getAs<PointerType>()->getPointeeType(); 421 if (!ValType->isIntegerType() && !ValType->isPointerType() && 422 !ValType->isBlockPointerType()) { 423 Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer_intptr) 424 << FirstArg->getType() << FirstArg->getSourceRange(); 425 return ExprError(); 426 } 427 428 // The majority of builtins return a value, but a few have special return 429 // types, so allow them to override appropriately below. 430 QualType ResultType = ValType; 431 432 // We need to figure out which concrete builtin this maps onto. For example, 433 // __sync_fetch_and_add with a 2 byte object turns into 434 // __sync_fetch_and_add_2. 435#define BUILTIN_ROW(x) \ 436 { Builtin::BI##x##_1, Builtin::BI##x##_2, Builtin::BI##x##_4, \ 437 Builtin::BI##x##_8, Builtin::BI##x##_16 } 438 439 static const unsigned BuiltinIndices[][5] = { 440 BUILTIN_ROW(__sync_fetch_and_add), 441 BUILTIN_ROW(__sync_fetch_and_sub), 442 BUILTIN_ROW(__sync_fetch_and_or), 443 BUILTIN_ROW(__sync_fetch_and_and), 444 BUILTIN_ROW(__sync_fetch_and_xor), 445 446 BUILTIN_ROW(__sync_add_and_fetch), 447 BUILTIN_ROW(__sync_sub_and_fetch), 448 BUILTIN_ROW(__sync_and_and_fetch), 449 BUILTIN_ROW(__sync_or_and_fetch), 450 BUILTIN_ROW(__sync_xor_and_fetch), 451 452 BUILTIN_ROW(__sync_val_compare_and_swap), 453 BUILTIN_ROW(__sync_bool_compare_and_swap), 454 BUILTIN_ROW(__sync_lock_test_and_set), 455 BUILTIN_ROW(__sync_lock_release) 456 }; 457#undef BUILTIN_ROW 458 459 // Determine the index of the size. 460 unsigned SizeIndex; 461 switch (Context.getTypeSizeInChars(ValType).getQuantity()) { 462 case 1: SizeIndex = 0; break; 463 case 2: SizeIndex = 1; break; 464 case 4: SizeIndex = 2; break; 465 case 8: SizeIndex = 3; break; 466 case 16: SizeIndex = 4; break; 467 default: 468 Diag(DRE->getLocStart(), diag::err_atomic_builtin_pointer_size) 469 << FirstArg->getType() << FirstArg->getSourceRange(); 470 return ExprError(); 471 } 472 473 // Each of these builtins has one pointer argument, followed by some number of 474 // values (0, 1 or 2) followed by a potentially empty varags list of stuff 475 // that we ignore. Find out which row of BuiltinIndices to read from as well 476 // as the number of fixed args. 477 unsigned BuiltinID = FDecl->getBuiltinID(); 478 unsigned BuiltinIndex, NumFixed = 1; 479 switch (BuiltinID) { 480 default: assert(0 && "Unknown overloaded atomic builtin!"); 481 case Builtin::BI__sync_fetch_and_add: BuiltinIndex = 0; break; 482 case Builtin::BI__sync_fetch_and_sub: BuiltinIndex = 1; break; 483 case Builtin::BI__sync_fetch_and_or: BuiltinIndex = 2; break; 484 case Builtin::BI__sync_fetch_and_and: BuiltinIndex = 3; break; 485 case Builtin::BI__sync_fetch_and_xor: BuiltinIndex = 4; break; 486 487 case Builtin::BI__sync_add_and_fetch: BuiltinIndex = 5; break; 488 case Builtin::BI__sync_sub_and_fetch: BuiltinIndex = 6; break; 489 case Builtin::BI__sync_and_and_fetch: BuiltinIndex = 7; break; 490 case Builtin::BI__sync_or_and_fetch: BuiltinIndex = 8; break; 491 case Builtin::BI__sync_xor_and_fetch: BuiltinIndex = 9; break; 492 493 case Builtin::BI__sync_val_compare_and_swap: 494 BuiltinIndex = 10; 495 NumFixed = 2; 496 break; 497 case Builtin::BI__sync_bool_compare_and_swap: 498 BuiltinIndex = 11; 499 NumFixed = 2; 500 ResultType = Context.BoolTy; 501 break; 502 case Builtin::BI__sync_lock_test_and_set: BuiltinIndex = 12; break; 503 case Builtin::BI__sync_lock_release: 504 BuiltinIndex = 13; 505 NumFixed = 0; 506 ResultType = Context.VoidTy; 507 break; 508 } 509 510 // Now that we know how many fixed arguments we expect, first check that we 511 // have at least that many. 512 if (TheCall->getNumArgs() < 1+NumFixed) { 513 Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args_at_least) 514 << 0 << 1+NumFixed << TheCall->getNumArgs() 515 << TheCall->getCallee()->getSourceRange(); 516 return ExprError(); 517 } 518 519 // Get the decl for the concrete builtin from this, we can tell what the 520 // concrete integer type we should convert to is. 521 unsigned NewBuiltinID = BuiltinIndices[BuiltinIndex][SizeIndex]; 522 const char *NewBuiltinName = Context.BuiltinInfo.GetName(NewBuiltinID); 523 IdentifierInfo *NewBuiltinII = PP.getIdentifierInfo(NewBuiltinName); 524 FunctionDecl *NewBuiltinDecl = 525 cast<FunctionDecl>(LazilyCreateBuiltin(NewBuiltinII, NewBuiltinID, 526 TUScope, false, DRE->getLocStart())); 527 528 // The first argument --- the pointer --- has a fixed type; we 529 // deduce the types of the rest of the arguments accordingly. Walk 530 // the remaining arguments, converting them to the deduced value type. 531 for (unsigned i = 0; i != NumFixed; ++i) { 532 Expr *Arg = TheCall->getArg(i+1); 533 534 // If the argument is an implicit cast, then there was a promotion due to 535 // "...", just remove it now. 536 if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(Arg)) { 537 Arg = ICE->getSubExpr(); 538 ICE->setSubExpr(0); 539 TheCall->setArg(i+1, Arg); 540 } 541 542 // GCC does an implicit conversion to the pointer or integer ValType. This 543 // can fail in some cases (1i -> int**), check for this error case now. 544 CastExpr::CastKind Kind = CastExpr::CK_Unknown; 545 CXXCastPath BasePath; 546 if (CheckCastTypes(Arg->getSourceRange(), ValType, Arg, Kind, BasePath)) 547 return ExprError(); 548 549 // Okay, we have something that *can* be converted to the right type. Check 550 // to see if there is a potentially weird extension going on here. This can 551 // happen when you do an atomic operation on something like an char* and 552 // pass in 42. The 42 gets converted to char. This is even more strange 553 // for things like 45.123 -> char, etc. 554 // FIXME: Do this check. 555 ImpCastExprToType(Arg, ValType, Kind, ImplicitCastExpr::RValue, &BasePath); 556 TheCall->setArg(i+1, Arg); 557 } 558 559 // Switch the DeclRefExpr to refer to the new decl. 560 DRE->setDecl(NewBuiltinDecl); 561 DRE->setType(NewBuiltinDecl->getType()); 562 563 // Set the callee in the CallExpr. 564 // FIXME: This leaks the original parens and implicit casts. 565 Expr *PromotedCall = DRE; 566 UsualUnaryConversions(PromotedCall); 567 TheCall->setCallee(PromotedCall); 568 569 // Change the result type of the call to match the original value type. This 570 // is arbitrary, but the codegen for these builtins ins design to handle it 571 // gracefully. 572 TheCall->setType(ResultType); 573 574 return move(TheCallResult); 575} 576 577 578/// CheckObjCString - Checks that the argument to the builtin 579/// CFString constructor is correct 580/// FIXME: GCC currently emits the following warning: 581/// "warning: input conversion stopped due to an input byte that does not 582/// belong to the input codeset UTF-8" 583/// Note: It might also make sense to do the UTF-16 conversion here (would 584/// simplify the backend). 585bool Sema::CheckObjCString(Expr *Arg) { 586 Arg = Arg->IgnoreParenCasts(); 587 StringLiteral *Literal = dyn_cast<StringLiteral>(Arg); 588 589 if (!Literal || Literal->isWide()) { 590 Diag(Arg->getLocStart(), diag::err_cfstring_literal_not_string_constant) 591 << Arg->getSourceRange(); 592 return true; 593 } 594 595 size_t NulPos = Literal->getString().find('\0'); 596 if (NulPos != llvm::StringRef::npos) { 597 Diag(getLocationOfStringLiteralByte(Literal, NulPos), 598 diag::warn_cfstring_literal_contains_nul_character) 599 << Arg->getSourceRange(); 600 } 601 602 return false; 603} 604 605/// SemaBuiltinVAStart - Check the arguments to __builtin_va_start for validity. 606/// Emit an error and return true on failure, return false on success. 607bool Sema::SemaBuiltinVAStart(CallExpr *TheCall) { 608 Expr *Fn = TheCall->getCallee(); 609 if (TheCall->getNumArgs() > 2) { 610 Diag(TheCall->getArg(2)->getLocStart(), 611 diag::err_typecheck_call_too_many_args) 612 << 0 /*function call*/ << 2 << TheCall->getNumArgs() 613 << Fn->getSourceRange() 614 << SourceRange(TheCall->getArg(2)->getLocStart(), 615 (*(TheCall->arg_end()-1))->getLocEnd()); 616 return true; 617 } 618 619 if (TheCall->getNumArgs() < 2) { 620 return Diag(TheCall->getLocEnd(), 621 diag::err_typecheck_call_too_few_args_at_least) 622 << 0 /*function call*/ << 2 << TheCall->getNumArgs(); 623 } 624 625 // Determine whether the current function is variadic or not. 626 BlockScopeInfo *CurBlock = getCurBlock(); 627 bool isVariadic; 628 if (CurBlock) 629 isVariadic = CurBlock->TheDecl->isVariadic(); 630 else if (FunctionDecl *FD = getCurFunctionDecl()) 631 isVariadic = FD->isVariadic(); 632 else 633 isVariadic = getCurMethodDecl()->isVariadic(); 634 635 if (!isVariadic) { 636 Diag(Fn->getLocStart(), diag::err_va_start_used_in_non_variadic_function); 637 return true; 638 } 639 640 // Verify that the second argument to the builtin is the last argument of the 641 // current function or method. 642 bool SecondArgIsLastNamedArgument = false; 643 const Expr *Arg = TheCall->getArg(1)->IgnoreParenCasts(); 644 645 if (const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(Arg)) { 646 if (const ParmVarDecl *PV = dyn_cast<ParmVarDecl>(DR->getDecl())) { 647 // FIXME: This isn't correct for methods (results in bogus warning). 648 // Get the last formal in the current function. 649 const ParmVarDecl *LastArg; 650 if (CurBlock) 651 LastArg = *(CurBlock->TheDecl->param_end()-1); 652 else if (FunctionDecl *FD = getCurFunctionDecl()) 653 LastArg = *(FD->param_end()-1); 654 else 655 LastArg = *(getCurMethodDecl()->param_end()-1); 656 SecondArgIsLastNamedArgument = PV == LastArg; 657 } 658 } 659 660 if (!SecondArgIsLastNamedArgument) 661 Diag(TheCall->getArg(1)->getLocStart(), 662 diag::warn_second_parameter_of_va_start_not_last_named_argument); 663 return false; 664} 665 666/// SemaBuiltinUnorderedCompare - Handle functions like __builtin_isgreater and 667/// friends. This is declared to take (...), so we have to check everything. 668bool Sema::SemaBuiltinUnorderedCompare(CallExpr *TheCall) { 669 if (TheCall->getNumArgs() < 2) 670 return Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args) 671 << 0 << 2 << TheCall->getNumArgs()/*function call*/; 672 if (TheCall->getNumArgs() > 2) 673 return Diag(TheCall->getArg(2)->getLocStart(), 674 diag::err_typecheck_call_too_many_args) 675 << 0 /*function call*/ << 2 << TheCall->getNumArgs() 676 << SourceRange(TheCall->getArg(2)->getLocStart(), 677 (*(TheCall->arg_end()-1))->getLocEnd()); 678 679 Expr *OrigArg0 = TheCall->getArg(0); 680 Expr *OrigArg1 = TheCall->getArg(1); 681 682 // Do standard promotions between the two arguments, returning their common 683 // type. 684 QualType Res = UsualArithmeticConversions(OrigArg0, OrigArg1, false); 685 686 // Make sure any conversions are pushed back into the call; this is 687 // type safe since unordered compare builtins are declared as "_Bool 688 // foo(...)". 689 TheCall->setArg(0, OrigArg0); 690 TheCall->setArg(1, OrigArg1); 691 692 if (OrigArg0->isTypeDependent() || OrigArg1->isTypeDependent()) 693 return false; 694 695 // If the common type isn't a real floating type, then the arguments were 696 // invalid for this operation. 697 if (!Res->isRealFloatingType()) 698 return Diag(OrigArg0->getLocStart(), 699 diag::err_typecheck_call_invalid_ordered_compare) 700 << OrigArg0->getType() << OrigArg1->getType() 701 << SourceRange(OrigArg0->getLocStart(), OrigArg1->getLocEnd()); 702 703 return false; 704} 705 706/// SemaBuiltinSemaBuiltinFPClassification - Handle functions like 707/// __builtin_isnan and friends. This is declared to take (...), so we have 708/// to check everything. We expect the last argument to be a floating point 709/// value. 710bool Sema::SemaBuiltinFPClassification(CallExpr *TheCall, unsigned NumArgs) { 711 if (TheCall->getNumArgs() < NumArgs) 712 return Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args) 713 << 0 << NumArgs << TheCall->getNumArgs()/*function call*/; 714 if (TheCall->getNumArgs() > NumArgs) 715 return Diag(TheCall->getArg(NumArgs)->getLocStart(), 716 diag::err_typecheck_call_too_many_args) 717 << 0 /*function call*/ << NumArgs << TheCall->getNumArgs() 718 << SourceRange(TheCall->getArg(NumArgs)->getLocStart(), 719 (*(TheCall->arg_end()-1))->getLocEnd()); 720 721 Expr *OrigArg = TheCall->getArg(NumArgs-1); 722 723 if (OrigArg->isTypeDependent()) 724 return false; 725 726 // This operation requires a non-_Complex floating-point number. 727 if (!OrigArg->getType()->isRealFloatingType()) 728 return Diag(OrigArg->getLocStart(), 729 diag::err_typecheck_call_invalid_unary_fp) 730 << OrigArg->getType() << OrigArg->getSourceRange(); 731 732 // If this is an implicit conversion from float -> double, remove it. 733 if (ImplicitCastExpr *Cast = dyn_cast<ImplicitCastExpr>(OrigArg)) { 734 Expr *CastArg = Cast->getSubExpr(); 735 if (CastArg->getType()->isSpecificBuiltinType(BuiltinType::Float)) { 736 assert(Cast->getType()->isSpecificBuiltinType(BuiltinType::Double) && 737 "promotion from float to double is the only expected cast here"); 738 Cast->setSubExpr(0); 739 TheCall->setArg(NumArgs-1, CastArg); 740 OrigArg = CastArg; 741 } 742 } 743 744 return false; 745} 746 747/// SemaBuiltinShuffleVector - Handle __builtin_shufflevector. 748// This is declared to take (...), so we have to check everything. 749ExprResult Sema::SemaBuiltinShuffleVector(CallExpr *TheCall) { 750 if (TheCall->getNumArgs() < 2) 751 return ExprError(Diag(TheCall->getLocEnd(), 752 diag::err_typecheck_call_too_few_args_at_least) 753 << 0 /*function call*/ << 2 << TheCall->getNumArgs() 754 << TheCall->getSourceRange()); 755 756 // Determine which of the following types of shufflevector we're checking: 757 // 1) unary, vector mask: (lhs, mask) 758 // 2) binary, vector mask: (lhs, rhs, mask) 759 // 3) binary, scalar mask: (lhs, rhs, index, ..., index) 760 QualType resType = TheCall->getArg(0)->getType(); 761 unsigned numElements = 0; 762 763 if (!TheCall->getArg(0)->isTypeDependent() && 764 !TheCall->getArg(1)->isTypeDependent()) { 765 QualType LHSType = TheCall->getArg(0)->getType(); 766 QualType RHSType = TheCall->getArg(1)->getType(); 767 768 if (!LHSType->isVectorType() || !RHSType->isVectorType()) { 769 Diag(TheCall->getLocStart(), diag::err_shufflevector_non_vector) 770 << SourceRange(TheCall->getArg(0)->getLocStart(), 771 TheCall->getArg(1)->getLocEnd()); 772 return ExprError(); 773 } 774 775 numElements = LHSType->getAs<VectorType>()->getNumElements(); 776 unsigned numResElements = TheCall->getNumArgs() - 2; 777 778 // Check to see if we have a call with 2 vector arguments, the unary shuffle 779 // with mask. If so, verify that RHS is an integer vector type with the 780 // same number of elts as lhs. 781 if (TheCall->getNumArgs() == 2) { 782 if (!RHSType->hasIntegerRepresentation() || 783 RHSType->getAs<VectorType>()->getNumElements() != numElements) 784 Diag(TheCall->getLocStart(), diag::err_shufflevector_incompatible_vector) 785 << SourceRange(TheCall->getArg(1)->getLocStart(), 786 TheCall->getArg(1)->getLocEnd()); 787 numResElements = numElements; 788 } 789 else if (!Context.hasSameUnqualifiedType(LHSType, RHSType)) { 790 Diag(TheCall->getLocStart(), diag::err_shufflevector_incompatible_vector) 791 << SourceRange(TheCall->getArg(0)->getLocStart(), 792 TheCall->getArg(1)->getLocEnd()); 793 return ExprError(); 794 } else if (numElements != numResElements) { 795 QualType eltType = LHSType->getAs<VectorType>()->getElementType(); 796 resType = Context.getVectorType(eltType, numResElements, 797 VectorType::NotAltiVec); 798 } 799 } 800 801 for (unsigned i = 2; i < TheCall->getNumArgs(); i++) { 802 if (TheCall->getArg(i)->isTypeDependent() || 803 TheCall->getArg(i)->isValueDependent()) 804 continue; 805 806 llvm::APSInt Result(32); 807 if (!TheCall->getArg(i)->isIntegerConstantExpr(Result, Context)) 808 return ExprError(Diag(TheCall->getLocStart(), 809 diag::err_shufflevector_nonconstant_argument) 810 << TheCall->getArg(i)->getSourceRange()); 811 812 if (Result.getActiveBits() > 64 || Result.getZExtValue() >= numElements*2) 813 return ExprError(Diag(TheCall->getLocStart(), 814 diag::err_shufflevector_argument_too_large) 815 << TheCall->getArg(i)->getSourceRange()); 816 } 817 818 llvm::SmallVector<Expr*, 32> exprs; 819 820 for (unsigned i = 0, e = TheCall->getNumArgs(); i != e; i++) { 821 exprs.push_back(TheCall->getArg(i)); 822 TheCall->setArg(i, 0); 823 } 824 825 return Owned(new (Context) ShuffleVectorExpr(Context, exprs.begin(), 826 exprs.size(), resType, 827 TheCall->getCallee()->getLocStart(), 828 TheCall->getRParenLoc())); 829} 830 831/// SemaBuiltinPrefetch - Handle __builtin_prefetch. 832// This is declared to take (const void*, ...) and can take two 833// optional constant int args. 834bool Sema::SemaBuiltinPrefetch(CallExpr *TheCall) { 835 unsigned NumArgs = TheCall->getNumArgs(); 836 837 if (NumArgs > 3) 838 return Diag(TheCall->getLocEnd(), 839 diag::err_typecheck_call_too_many_args_at_most) 840 << 0 /*function call*/ << 3 << NumArgs 841 << TheCall->getSourceRange(); 842 843 // Argument 0 is checked for us and the remaining arguments must be 844 // constant integers. 845 for (unsigned i = 1; i != NumArgs; ++i) { 846 Expr *Arg = TheCall->getArg(i); 847 848 llvm::APSInt Result; 849 if (SemaBuiltinConstantArg(TheCall, i, Result)) 850 return true; 851 852 // FIXME: gcc issues a warning and rewrites these to 0. These 853 // seems especially odd for the third argument since the default 854 // is 3. 855 if (i == 1) { 856 if (Result.getLimitedValue() > 1) 857 return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range) 858 << "0" << "1" << Arg->getSourceRange(); 859 } else { 860 if (Result.getLimitedValue() > 3) 861 return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range) 862 << "0" << "3" << Arg->getSourceRange(); 863 } 864 } 865 866 return false; 867} 868 869/// SemaBuiltinConstantArg - Handle a check if argument ArgNum of CallExpr 870/// TheCall is a constant expression. 871bool Sema::SemaBuiltinConstantArg(CallExpr *TheCall, int ArgNum, 872 llvm::APSInt &Result) { 873 Expr *Arg = TheCall->getArg(ArgNum); 874 DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts()); 875 FunctionDecl *FDecl = cast<FunctionDecl>(DRE->getDecl()); 876 877 if (Arg->isTypeDependent() || Arg->isValueDependent()) return false; 878 879 if (!Arg->isIntegerConstantExpr(Result, Context)) 880 return Diag(TheCall->getLocStart(), diag::err_constant_integer_arg_type) 881 << FDecl->getDeclName() << Arg->getSourceRange(); 882 883 return false; 884} 885 886/// SemaBuiltinObjectSize - Handle __builtin_object_size(void *ptr, 887/// int type). This simply type checks that type is one of the defined 888/// constants (0-3). 889// For compatability check 0-3, llvm only handles 0 and 2. 890bool Sema::SemaBuiltinObjectSize(CallExpr *TheCall) { 891 llvm::APSInt Result; 892 893 // Check constant-ness first. 894 if (SemaBuiltinConstantArg(TheCall, 1, Result)) 895 return true; 896 897 Expr *Arg = TheCall->getArg(1); 898 if (Result.getSExtValue() < 0 || Result.getSExtValue() > 3) { 899 return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range) 900 << "0" << "3" << SourceRange(Arg->getLocStart(), Arg->getLocEnd()); 901 } 902 903 return false; 904} 905 906/// SemaBuiltinLongjmp - Handle __builtin_longjmp(void *env[5], int val). 907/// This checks that val is a constant 1. 908bool Sema::SemaBuiltinLongjmp(CallExpr *TheCall) { 909 Expr *Arg = TheCall->getArg(1); 910 llvm::APSInt Result; 911 912 // TODO: This is less than ideal. Overload this to take a value. 913 if (SemaBuiltinConstantArg(TheCall, 1, Result)) 914 return true; 915 916 if (Result != 1) 917 return Diag(TheCall->getLocStart(), diag::err_builtin_longjmp_invalid_val) 918 << SourceRange(Arg->getLocStart(), Arg->getLocEnd()); 919 920 return false; 921} 922 923// Handle i > 1 ? "x" : "y", recursivelly 924bool Sema::SemaCheckStringLiteral(const Expr *E, const CallExpr *TheCall, 925 bool HasVAListArg, 926 unsigned format_idx, unsigned firstDataArg, 927 bool isPrintf) { 928 929 if (E->isTypeDependent() || E->isValueDependent()) 930 return false; 931 932 switch (E->getStmtClass()) { 933 case Stmt::ConditionalOperatorClass: { 934 const ConditionalOperator *C = cast<ConditionalOperator>(E); 935 return SemaCheckStringLiteral(C->getTrueExpr(), TheCall, HasVAListArg, 936 format_idx, firstDataArg, isPrintf) 937 && SemaCheckStringLiteral(C->getRHS(), TheCall, HasVAListArg, 938 format_idx, firstDataArg, isPrintf); 939 } 940 941 case Stmt::ImplicitCastExprClass: { 942 const ImplicitCastExpr *Expr = cast<ImplicitCastExpr>(E); 943 return SemaCheckStringLiteral(Expr->getSubExpr(), TheCall, HasVAListArg, 944 format_idx, firstDataArg, isPrintf); 945 } 946 947 case Stmt::ParenExprClass: { 948 const ParenExpr *Expr = cast<ParenExpr>(E); 949 return SemaCheckStringLiteral(Expr->getSubExpr(), TheCall, HasVAListArg, 950 format_idx, firstDataArg, isPrintf); 951 } 952 953 case Stmt::DeclRefExprClass: { 954 const DeclRefExpr *DR = cast<DeclRefExpr>(E); 955 956 // As an exception, do not flag errors for variables binding to 957 // const string literals. 958 if (const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl())) { 959 bool isConstant = false; 960 QualType T = DR->getType(); 961 962 if (const ArrayType *AT = Context.getAsArrayType(T)) { 963 isConstant = AT->getElementType().isConstant(Context); 964 } else if (const PointerType *PT = T->getAs<PointerType>()) { 965 isConstant = T.isConstant(Context) && 966 PT->getPointeeType().isConstant(Context); 967 } 968 969 if (isConstant) { 970 if (const Expr *Init = VD->getAnyInitializer()) 971 return SemaCheckStringLiteral(Init, TheCall, 972 HasVAListArg, format_idx, firstDataArg, 973 isPrintf); 974 } 975 976 // For vprintf* functions (i.e., HasVAListArg==true), we add a 977 // special check to see if the format string is a function parameter 978 // of the function calling the printf function. If the function 979 // has an attribute indicating it is a printf-like function, then we 980 // should suppress warnings concerning non-literals being used in a call 981 // to a vprintf function. For example: 982 // 983 // void 984 // logmessage(char const *fmt __attribute__ (format (printf, 1, 2)), ...){ 985 // va_list ap; 986 // va_start(ap, fmt); 987 // vprintf(fmt, ap); // Do NOT emit a warning about "fmt". 988 // ... 989 // 990 // 991 // FIXME: We don't have full attribute support yet, so just check to see 992 // if the argument is a DeclRefExpr that references a parameter. We'll 993 // add proper support for checking the attribute later. 994 if (HasVAListArg) 995 if (isa<ParmVarDecl>(VD)) 996 return true; 997 } 998 999 return false; 1000 } 1001 1002 case Stmt::CallExprClass: { 1003 const CallExpr *CE = cast<CallExpr>(E); 1004 if (const ImplicitCastExpr *ICE 1005 = dyn_cast<ImplicitCastExpr>(CE->getCallee())) { 1006 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(ICE->getSubExpr())) { 1007 if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(DRE->getDecl())) { 1008 if (const FormatArgAttr *FA = FD->getAttr<FormatArgAttr>()) { 1009 unsigned ArgIndex = FA->getFormatIdx(); 1010 const Expr *Arg = CE->getArg(ArgIndex - 1); 1011 1012 return SemaCheckStringLiteral(Arg, TheCall, HasVAListArg, 1013 format_idx, firstDataArg, isPrintf); 1014 } 1015 } 1016 } 1017 } 1018 1019 return false; 1020 } 1021 case Stmt::ObjCStringLiteralClass: 1022 case Stmt::StringLiteralClass: { 1023 const StringLiteral *StrE = NULL; 1024 1025 if (const ObjCStringLiteral *ObjCFExpr = dyn_cast<ObjCStringLiteral>(E)) 1026 StrE = ObjCFExpr->getString(); 1027 else 1028 StrE = cast<StringLiteral>(E); 1029 1030 if (StrE) { 1031 CheckFormatString(StrE, E, TheCall, HasVAListArg, format_idx, 1032 firstDataArg, isPrintf); 1033 return true; 1034 } 1035 1036 return false; 1037 } 1038 1039 default: 1040 return false; 1041 } 1042} 1043 1044void 1045Sema::CheckNonNullArguments(const NonNullAttr *NonNull, 1046 const CallExpr *TheCall) { 1047 for (NonNullAttr::args_iterator i = NonNull->args_begin(), 1048 e = NonNull->args_end(); 1049 i != e; ++i) { 1050 const Expr *ArgExpr = TheCall->getArg(*i); 1051 if (ArgExpr->isNullPointerConstant(Context, 1052 Expr::NPC_ValueDependentIsNotNull)) 1053 Diag(TheCall->getCallee()->getLocStart(), diag::warn_null_arg) 1054 << ArgExpr->getSourceRange(); 1055 } 1056} 1057 1058/// CheckPrintfScanfArguments - Check calls to printf and scanf (and similar 1059/// functions) for correct use of format strings. 1060void 1061Sema::CheckPrintfScanfArguments(const CallExpr *TheCall, bool HasVAListArg, 1062 unsigned format_idx, unsigned firstDataArg, 1063 bool isPrintf) { 1064 1065 const Expr *Fn = TheCall->getCallee(); 1066 1067 // The way the format attribute works in GCC, the implicit this argument 1068 // of member functions is counted. However, it doesn't appear in our own 1069 // lists, so decrement format_idx in that case. 1070 if (isa<CXXMemberCallExpr>(TheCall)) { 1071 // Catch a format attribute mistakenly referring to the object argument. 1072 if (format_idx == 0) 1073 return; 1074 --format_idx; 1075 if(firstDataArg != 0) 1076 --firstDataArg; 1077 } 1078 1079 // CHECK: printf/scanf-like function is called with no format string. 1080 if (format_idx >= TheCall->getNumArgs()) { 1081 Diag(TheCall->getRParenLoc(), diag::warn_missing_format_string) 1082 << Fn->getSourceRange(); 1083 return; 1084 } 1085 1086 const Expr *OrigFormatExpr = TheCall->getArg(format_idx)->IgnoreParenCasts(); 1087 1088 // CHECK: format string is not a string literal. 1089 // 1090 // Dynamically generated format strings are difficult to 1091 // automatically vet at compile time. Requiring that format strings 1092 // are string literals: (1) permits the checking of format strings by 1093 // the compiler and thereby (2) can practically remove the source of 1094 // many format string exploits. 1095 1096 // Format string can be either ObjC string (e.g. @"%d") or 1097 // C string (e.g. "%d") 1098 // ObjC string uses the same format specifiers as C string, so we can use 1099 // the same format string checking logic for both ObjC and C strings. 1100 if (SemaCheckStringLiteral(OrigFormatExpr, TheCall, HasVAListArg, format_idx, 1101 firstDataArg, isPrintf)) 1102 return; // Literal format string found, check done! 1103 1104 // If there are no arguments specified, warn with -Wformat-security, otherwise 1105 // warn only with -Wformat-nonliteral. 1106 if (TheCall->getNumArgs() == format_idx+1) 1107 Diag(TheCall->getArg(format_idx)->getLocStart(), 1108 diag::warn_format_nonliteral_noargs) 1109 << OrigFormatExpr->getSourceRange(); 1110 else 1111 Diag(TheCall->getArg(format_idx)->getLocStart(), 1112 diag::warn_format_nonliteral) 1113 << OrigFormatExpr->getSourceRange(); 1114} 1115 1116namespace { 1117class CheckFormatHandler : public analyze_format_string::FormatStringHandler { 1118protected: 1119 Sema &S; 1120 const StringLiteral *FExpr; 1121 const Expr *OrigFormatExpr; 1122 const unsigned FirstDataArg; 1123 const unsigned NumDataArgs; 1124 const bool IsObjCLiteral; 1125 const char *Beg; // Start of format string. 1126 const bool HasVAListArg; 1127 const CallExpr *TheCall; 1128 unsigned FormatIdx; 1129 llvm::BitVector CoveredArgs; 1130 bool usesPositionalArgs; 1131 bool atFirstArg; 1132public: 1133 CheckFormatHandler(Sema &s, const StringLiteral *fexpr, 1134 const Expr *origFormatExpr, unsigned firstDataArg, 1135 unsigned numDataArgs, bool isObjCLiteral, 1136 const char *beg, bool hasVAListArg, 1137 const CallExpr *theCall, unsigned formatIdx) 1138 : S(s), FExpr(fexpr), OrigFormatExpr(origFormatExpr), 1139 FirstDataArg(firstDataArg), 1140 NumDataArgs(numDataArgs), 1141 IsObjCLiteral(isObjCLiteral), Beg(beg), 1142 HasVAListArg(hasVAListArg), 1143 TheCall(theCall), FormatIdx(formatIdx), 1144 usesPositionalArgs(false), atFirstArg(true) { 1145 CoveredArgs.resize(numDataArgs); 1146 CoveredArgs.reset(); 1147 } 1148 1149 void DoneProcessing(); 1150 1151 void HandleIncompleteSpecifier(const char *startSpecifier, 1152 unsigned specifierLen); 1153 1154 virtual void HandleInvalidPosition(const char *startSpecifier, 1155 unsigned specifierLen, 1156 analyze_format_string::PositionContext p); 1157 1158 virtual void HandleZeroPosition(const char *startPos, unsigned posLen); 1159 1160 void HandleNullChar(const char *nullCharacter); 1161 1162protected: 1163 bool HandleInvalidConversionSpecifier(unsigned argIndex, SourceLocation Loc, 1164 const char *startSpec, 1165 unsigned specifierLen, 1166 const char *csStart, unsigned csLen); 1167 1168 SourceRange getFormatStringRange(); 1169 CharSourceRange getSpecifierRange(const char *startSpecifier, 1170 unsigned specifierLen); 1171 SourceLocation getLocationOfByte(const char *x); 1172 1173 const Expr *getDataArg(unsigned i) const; 1174 1175 bool CheckNumArgs(const analyze_format_string::FormatSpecifier &FS, 1176 const analyze_format_string::ConversionSpecifier &CS, 1177 const char *startSpecifier, unsigned specifierLen, 1178 unsigned argIndex); 1179}; 1180} 1181 1182SourceRange CheckFormatHandler::getFormatStringRange() { 1183 return OrigFormatExpr->getSourceRange(); 1184} 1185 1186CharSourceRange CheckFormatHandler:: 1187getSpecifierRange(const char *startSpecifier, unsigned specifierLen) { 1188 SourceLocation Start = getLocationOfByte(startSpecifier); 1189 SourceLocation End = getLocationOfByte(startSpecifier + specifierLen - 1); 1190 1191 // Advance the end SourceLocation by one due to half-open ranges. 1192 End = End.getFileLocWithOffset(1); 1193 1194 return CharSourceRange::getCharRange(Start, End); 1195} 1196 1197SourceLocation CheckFormatHandler::getLocationOfByte(const char *x) { 1198 return S.getLocationOfStringLiteralByte(FExpr, x - Beg); 1199} 1200 1201void CheckFormatHandler::HandleIncompleteSpecifier(const char *startSpecifier, 1202 unsigned specifierLen){ 1203 SourceLocation Loc = getLocationOfByte(startSpecifier); 1204 S.Diag(Loc, diag::warn_printf_incomplete_specifier) 1205 << getSpecifierRange(startSpecifier, specifierLen); 1206} 1207 1208void 1209CheckFormatHandler::HandleInvalidPosition(const char *startPos, unsigned posLen, 1210 analyze_format_string::PositionContext p) { 1211 SourceLocation Loc = getLocationOfByte(startPos); 1212 S.Diag(Loc, diag::warn_format_invalid_positional_specifier) 1213 << (unsigned) p << getSpecifierRange(startPos, posLen); 1214} 1215 1216void CheckFormatHandler::HandleZeroPosition(const char *startPos, 1217 unsigned posLen) { 1218 SourceLocation Loc = getLocationOfByte(startPos); 1219 S.Diag(Loc, diag::warn_format_zero_positional_specifier) 1220 << getSpecifierRange(startPos, posLen); 1221} 1222 1223void CheckFormatHandler::HandleNullChar(const char *nullCharacter) { 1224 // The presence of a null character is likely an error. 1225 S.Diag(getLocationOfByte(nullCharacter), 1226 diag::warn_printf_format_string_contains_null_char) 1227 << getFormatStringRange(); 1228} 1229 1230const Expr *CheckFormatHandler::getDataArg(unsigned i) const { 1231 return TheCall->getArg(FirstDataArg + i); 1232} 1233 1234void CheckFormatHandler::DoneProcessing() { 1235 // Does the number of data arguments exceed the number of 1236 // format conversions in the format string? 1237 if (!HasVAListArg) { 1238 // Find any arguments that weren't covered. 1239 CoveredArgs.flip(); 1240 signed notCoveredArg = CoveredArgs.find_first(); 1241 if (notCoveredArg >= 0) { 1242 assert((unsigned)notCoveredArg < NumDataArgs); 1243 S.Diag(getDataArg((unsigned) notCoveredArg)->getLocStart(), 1244 diag::warn_printf_data_arg_not_used) 1245 << getFormatStringRange(); 1246 } 1247 } 1248} 1249 1250bool 1251CheckFormatHandler::HandleInvalidConversionSpecifier(unsigned argIndex, 1252 SourceLocation Loc, 1253 const char *startSpec, 1254 unsigned specifierLen, 1255 const char *csStart, 1256 unsigned csLen) { 1257 1258 bool keepGoing = true; 1259 if (argIndex < NumDataArgs) { 1260 // Consider the argument coverered, even though the specifier doesn't 1261 // make sense. 1262 CoveredArgs.set(argIndex); 1263 } 1264 else { 1265 // If argIndex exceeds the number of data arguments we 1266 // don't issue a warning because that is just a cascade of warnings (and 1267 // they may have intended '%%' anyway). We don't want to continue processing 1268 // the format string after this point, however, as we will like just get 1269 // gibberish when trying to match arguments. 1270 keepGoing = false; 1271 } 1272 1273 S.Diag(Loc, diag::warn_format_invalid_conversion) 1274 << llvm::StringRef(csStart, csLen) 1275 << getSpecifierRange(startSpec, specifierLen); 1276 1277 return keepGoing; 1278} 1279 1280bool 1281CheckFormatHandler::CheckNumArgs( 1282 const analyze_format_string::FormatSpecifier &FS, 1283 const analyze_format_string::ConversionSpecifier &CS, 1284 const char *startSpecifier, unsigned specifierLen, unsigned argIndex) { 1285 1286 if (argIndex >= NumDataArgs) { 1287 if (FS.usesPositionalArg()) { 1288 S.Diag(getLocationOfByte(CS.getStart()), 1289 diag::warn_printf_positional_arg_exceeds_data_args) 1290 << (argIndex+1) << NumDataArgs 1291 << getSpecifierRange(startSpecifier, specifierLen); 1292 } 1293 else { 1294 S.Diag(getLocationOfByte(CS.getStart()), 1295 diag::warn_printf_insufficient_data_args) 1296 << getSpecifierRange(startSpecifier, specifierLen); 1297 } 1298 1299 return false; 1300 } 1301 return true; 1302} 1303 1304//===--- CHECK: Printf format string checking ------------------------------===// 1305 1306namespace { 1307class CheckPrintfHandler : public CheckFormatHandler { 1308public: 1309 CheckPrintfHandler(Sema &s, const StringLiteral *fexpr, 1310 const Expr *origFormatExpr, unsigned firstDataArg, 1311 unsigned numDataArgs, bool isObjCLiteral, 1312 const char *beg, bool hasVAListArg, 1313 const CallExpr *theCall, unsigned formatIdx) 1314 : CheckFormatHandler(s, fexpr, origFormatExpr, firstDataArg, 1315 numDataArgs, isObjCLiteral, beg, hasVAListArg, 1316 theCall, formatIdx) {} 1317 1318 1319 bool HandleInvalidPrintfConversionSpecifier( 1320 const analyze_printf::PrintfSpecifier &FS, 1321 const char *startSpecifier, 1322 unsigned specifierLen); 1323 1324 bool HandlePrintfSpecifier(const analyze_printf::PrintfSpecifier &FS, 1325 const char *startSpecifier, 1326 unsigned specifierLen); 1327 1328 bool HandleAmount(const analyze_format_string::OptionalAmount &Amt, unsigned k, 1329 const char *startSpecifier, unsigned specifierLen); 1330 void HandleInvalidAmount(const analyze_printf::PrintfSpecifier &FS, 1331 const analyze_printf::OptionalAmount &Amt, 1332 unsigned type, 1333 const char *startSpecifier, unsigned specifierLen); 1334 void HandleFlag(const analyze_printf::PrintfSpecifier &FS, 1335 const analyze_printf::OptionalFlag &flag, 1336 const char *startSpecifier, unsigned specifierLen); 1337 void HandleIgnoredFlag(const analyze_printf::PrintfSpecifier &FS, 1338 const analyze_printf::OptionalFlag &ignoredFlag, 1339 const analyze_printf::OptionalFlag &flag, 1340 const char *startSpecifier, unsigned specifierLen); 1341}; 1342} 1343 1344bool CheckPrintfHandler::HandleInvalidPrintfConversionSpecifier( 1345 const analyze_printf::PrintfSpecifier &FS, 1346 const char *startSpecifier, 1347 unsigned specifierLen) { 1348 const analyze_printf::PrintfConversionSpecifier &CS = 1349 FS.getConversionSpecifier(); 1350 1351 return HandleInvalidConversionSpecifier(FS.getArgIndex(), 1352 getLocationOfByte(CS.getStart()), 1353 startSpecifier, specifierLen, 1354 CS.getStart(), CS.getLength()); 1355} 1356 1357bool CheckPrintfHandler::HandleAmount( 1358 const analyze_format_string::OptionalAmount &Amt, 1359 unsigned k, const char *startSpecifier, 1360 unsigned specifierLen) { 1361 1362 if (Amt.hasDataArgument()) { 1363 if (!HasVAListArg) { 1364 unsigned argIndex = Amt.getArgIndex(); 1365 if (argIndex >= NumDataArgs) { 1366 S.Diag(getLocationOfByte(Amt.getStart()), 1367 diag::warn_printf_asterisk_missing_arg) 1368 << k << getSpecifierRange(startSpecifier, specifierLen); 1369 // Don't do any more checking. We will just emit 1370 // spurious errors. 1371 return false; 1372 } 1373 1374 // Type check the data argument. It should be an 'int'. 1375 // Although not in conformance with C99, we also allow the argument to be 1376 // an 'unsigned int' as that is a reasonably safe case. GCC also 1377 // doesn't emit a warning for that case. 1378 CoveredArgs.set(argIndex); 1379 const Expr *Arg = getDataArg(argIndex); 1380 QualType T = Arg->getType(); 1381 1382 const analyze_printf::ArgTypeResult &ATR = Amt.getArgType(S.Context); 1383 assert(ATR.isValid()); 1384 1385 if (!ATR.matchesType(S.Context, T)) { 1386 S.Diag(getLocationOfByte(Amt.getStart()), 1387 diag::warn_printf_asterisk_wrong_type) 1388 << k 1389 << ATR.getRepresentativeType(S.Context) << T 1390 << getSpecifierRange(startSpecifier, specifierLen) 1391 << Arg->getSourceRange(); 1392 // Don't do any more checking. We will just emit 1393 // spurious errors. 1394 return false; 1395 } 1396 } 1397 } 1398 return true; 1399} 1400 1401void CheckPrintfHandler::HandleInvalidAmount( 1402 const analyze_printf::PrintfSpecifier &FS, 1403 const analyze_printf::OptionalAmount &Amt, 1404 unsigned type, 1405 const char *startSpecifier, 1406 unsigned specifierLen) { 1407 const analyze_printf::PrintfConversionSpecifier &CS = 1408 FS.getConversionSpecifier(); 1409 switch (Amt.getHowSpecified()) { 1410 case analyze_printf::OptionalAmount::Constant: 1411 S.Diag(getLocationOfByte(Amt.getStart()), 1412 diag::warn_printf_nonsensical_optional_amount) 1413 << type 1414 << CS.toString() 1415 << getSpecifierRange(startSpecifier, specifierLen) 1416 << FixItHint::CreateRemoval(getSpecifierRange(Amt.getStart(), 1417 Amt.getConstantLength())); 1418 break; 1419 1420 default: 1421 S.Diag(getLocationOfByte(Amt.getStart()), 1422 diag::warn_printf_nonsensical_optional_amount) 1423 << type 1424 << CS.toString() 1425 << getSpecifierRange(startSpecifier, specifierLen); 1426 break; 1427 } 1428} 1429 1430void CheckPrintfHandler::HandleFlag(const analyze_printf::PrintfSpecifier &FS, 1431 const analyze_printf::OptionalFlag &flag, 1432 const char *startSpecifier, 1433 unsigned specifierLen) { 1434 // Warn about pointless flag with a fixit removal. 1435 const analyze_printf::PrintfConversionSpecifier &CS = 1436 FS.getConversionSpecifier(); 1437 S.Diag(getLocationOfByte(flag.getPosition()), 1438 diag::warn_printf_nonsensical_flag) 1439 << flag.toString() << CS.toString() 1440 << getSpecifierRange(startSpecifier, specifierLen) 1441 << FixItHint::CreateRemoval(getSpecifierRange(flag.getPosition(), 1)); 1442} 1443 1444void CheckPrintfHandler::HandleIgnoredFlag( 1445 const analyze_printf::PrintfSpecifier &FS, 1446 const analyze_printf::OptionalFlag &ignoredFlag, 1447 const analyze_printf::OptionalFlag &flag, 1448 const char *startSpecifier, 1449 unsigned specifierLen) { 1450 // Warn about ignored flag with a fixit removal. 1451 S.Diag(getLocationOfByte(ignoredFlag.getPosition()), 1452 diag::warn_printf_ignored_flag) 1453 << ignoredFlag.toString() << flag.toString() 1454 << getSpecifierRange(startSpecifier, specifierLen) 1455 << FixItHint::CreateRemoval(getSpecifierRange( 1456 ignoredFlag.getPosition(), 1)); 1457} 1458 1459bool 1460CheckPrintfHandler::HandlePrintfSpecifier(const analyze_printf::PrintfSpecifier 1461 &FS, 1462 const char *startSpecifier, 1463 unsigned specifierLen) { 1464 1465 using namespace analyze_format_string; 1466 using namespace analyze_printf; 1467 const PrintfConversionSpecifier &CS = FS.getConversionSpecifier(); 1468 1469 if (FS.consumesDataArgument()) { 1470 if (atFirstArg) { 1471 atFirstArg = false; 1472 usesPositionalArgs = FS.usesPositionalArg(); 1473 } 1474 else if (usesPositionalArgs != FS.usesPositionalArg()) { 1475 // Cannot mix-and-match positional and non-positional arguments. 1476 S.Diag(getLocationOfByte(CS.getStart()), 1477 diag::warn_format_mix_positional_nonpositional_args) 1478 << getSpecifierRange(startSpecifier, specifierLen); 1479 return false; 1480 } 1481 } 1482 1483 // First check if the field width, precision, and conversion specifier 1484 // have matching data arguments. 1485 if (!HandleAmount(FS.getFieldWidth(), /* field width */ 0, 1486 startSpecifier, specifierLen)) { 1487 return false; 1488 } 1489 1490 if (!HandleAmount(FS.getPrecision(), /* precision */ 1, 1491 startSpecifier, specifierLen)) { 1492 return false; 1493 } 1494 1495 if (!CS.consumesDataArgument()) { 1496 // FIXME: Technically specifying a precision or field width here 1497 // makes no sense. Worth issuing a warning at some point. 1498 return true; 1499 } 1500 1501 // Consume the argument. 1502 unsigned argIndex = FS.getArgIndex(); 1503 if (argIndex < NumDataArgs) { 1504 // The check to see if the argIndex is valid will come later. 1505 // We set the bit here because we may exit early from this 1506 // function if we encounter some other error. 1507 CoveredArgs.set(argIndex); 1508 } 1509 1510 // Check for using an Objective-C specific conversion specifier 1511 // in a non-ObjC literal. 1512 if (!IsObjCLiteral && CS.isObjCArg()) { 1513 return HandleInvalidPrintfConversionSpecifier(FS, startSpecifier, 1514 specifierLen); 1515 } 1516 1517 // Check for invalid use of field width 1518 if (!FS.hasValidFieldWidth()) { 1519 HandleInvalidAmount(FS, FS.getFieldWidth(), /* field width */ 0, 1520 startSpecifier, specifierLen); 1521 } 1522 1523 // Check for invalid use of precision 1524 if (!FS.hasValidPrecision()) { 1525 HandleInvalidAmount(FS, FS.getPrecision(), /* precision */ 1, 1526 startSpecifier, specifierLen); 1527 } 1528 1529 // Check each flag does not conflict with any other component. 1530 if (!FS.hasValidLeadingZeros()) 1531 HandleFlag(FS, FS.hasLeadingZeros(), startSpecifier, specifierLen); 1532 if (!FS.hasValidPlusPrefix()) 1533 HandleFlag(FS, FS.hasPlusPrefix(), startSpecifier, specifierLen); 1534 if (!FS.hasValidSpacePrefix()) 1535 HandleFlag(FS, FS.hasSpacePrefix(), startSpecifier, specifierLen); 1536 if (!FS.hasValidAlternativeForm()) 1537 HandleFlag(FS, FS.hasAlternativeForm(), startSpecifier, specifierLen); 1538 if (!FS.hasValidLeftJustified()) 1539 HandleFlag(FS, FS.isLeftJustified(), startSpecifier, specifierLen); 1540 1541 // Check that flags are not ignored by another flag 1542 if (FS.hasSpacePrefix() && FS.hasPlusPrefix()) // ' ' ignored by '+' 1543 HandleIgnoredFlag(FS, FS.hasSpacePrefix(), FS.hasPlusPrefix(), 1544 startSpecifier, specifierLen); 1545 if (FS.hasLeadingZeros() && FS.isLeftJustified()) // '0' ignored by '-' 1546 HandleIgnoredFlag(FS, FS.hasLeadingZeros(), FS.isLeftJustified(), 1547 startSpecifier, specifierLen); 1548 1549 // Check the length modifier is valid with the given conversion specifier. 1550 const LengthModifier &LM = FS.getLengthModifier(); 1551 if (!FS.hasValidLengthModifier()) 1552 S.Diag(getLocationOfByte(LM.getStart()), 1553 diag::warn_format_nonsensical_length) 1554 << LM.toString() << CS.toString() 1555 << getSpecifierRange(startSpecifier, specifierLen) 1556 << FixItHint::CreateRemoval(getSpecifierRange(LM.getStart(), 1557 LM.getLength())); 1558 1559 // Are we using '%n'? 1560 if (CS.getKind() == ConversionSpecifier::nArg) { 1561 // Issue a warning about this being a possible security issue. 1562 S.Diag(getLocationOfByte(CS.getStart()), diag::warn_printf_write_back) 1563 << getSpecifierRange(startSpecifier, specifierLen); 1564 // Continue checking the other format specifiers. 1565 return true; 1566 } 1567 1568 // The remaining checks depend on the data arguments. 1569 if (HasVAListArg) 1570 return true; 1571 1572 if (!CheckNumArgs(FS, CS, startSpecifier, specifierLen, argIndex)) 1573 return false; 1574 1575 // Now type check the data expression that matches the 1576 // format specifier. 1577 const Expr *Ex = getDataArg(argIndex); 1578 const analyze_printf::ArgTypeResult &ATR = FS.getArgType(S.Context); 1579 if (ATR.isValid() && !ATR.matchesType(S.Context, Ex->getType())) { 1580 // Check if we didn't match because of an implicit cast from a 'char' 1581 // or 'short' to an 'int'. This is done because printf is a varargs 1582 // function. 1583 if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(Ex)) 1584 if (ICE->getType() == S.Context.IntTy) 1585 if (ATR.matchesType(S.Context, ICE->getSubExpr()->getType())) 1586 return true; 1587 1588 // We may be able to offer a FixItHint if it is a supported type. 1589 PrintfSpecifier fixedFS = FS; 1590 bool success = fixedFS.fixType(Ex->getType()); 1591 1592 if (success) { 1593 // Get the fix string from the fixed format specifier 1594 llvm::SmallString<128> buf; 1595 llvm::raw_svector_ostream os(buf); 1596 fixedFS.toString(os); 1597 1598 // FIXME: getRepresentativeType() perhaps should return a string 1599 // instead of a QualType to better handle when the representative 1600 // type is 'wint_t' (which is defined in the system headers). 1601 S.Diag(getLocationOfByte(CS.getStart()), 1602 diag::warn_printf_conversion_argument_type_mismatch) 1603 << ATR.getRepresentativeType(S.Context) << Ex->getType() 1604 << getSpecifierRange(startSpecifier, specifierLen) 1605 << Ex->getSourceRange() 1606 << FixItHint::CreateReplacement( 1607 getSpecifierRange(startSpecifier, specifierLen), 1608 os.str()); 1609 } 1610 else { 1611 S.Diag(getLocationOfByte(CS.getStart()), 1612 diag::warn_printf_conversion_argument_type_mismatch) 1613 << ATR.getRepresentativeType(S.Context) << Ex->getType() 1614 << getSpecifierRange(startSpecifier, specifierLen) 1615 << Ex->getSourceRange(); 1616 } 1617 } 1618 1619 return true; 1620} 1621 1622//===--- CHECK: Scanf format string checking ------------------------------===// 1623 1624namespace { 1625class CheckScanfHandler : public CheckFormatHandler { 1626public: 1627 CheckScanfHandler(Sema &s, const StringLiteral *fexpr, 1628 const Expr *origFormatExpr, unsigned firstDataArg, 1629 unsigned numDataArgs, bool isObjCLiteral, 1630 const char *beg, bool hasVAListArg, 1631 const CallExpr *theCall, unsigned formatIdx) 1632 : CheckFormatHandler(s, fexpr, origFormatExpr, firstDataArg, 1633 numDataArgs, isObjCLiteral, beg, hasVAListArg, 1634 theCall, formatIdx) {} 1635 1636 bool HandleScanfSpecifier(const analyze_scanf::ScanfSpecifier &FS, 1637 const char *startSpecifier, 1638 unsigned specifierLen); 1639 1640 bool HandleInvalidScanfConversionSpecifier( 1641 const analyze_scanf::ScanfSpecifier &FS, 1642 const char *startSpecifier, 1643 unsigned specifierLen); 1644 1645 void HandleIncompleteScanList(const char *start, const char *end); 1646}; 1647} 1648 1649void CheckScanfHandler::HandleIncompleteScanList(const char *start, 1650 const char *end) { 1651 S.Diag(getLocationOfByte(end), diag::warn_scanf_scanlist_incomplete) 1652 << getSpecifierRange(start, end - start); 1653} 1654 1655bool CheckScanfHandler::HandleInvalidScanfConversionSpecifier( 1656 const analyze_scanf::ScanfSpecifier &FS, 1657 const char *startSpecifier, 1658 unsigned specifierLen) { 1659 1660 const analyze_scanf::ScanfConversionSpecifier &CS = 1661 FS.getConversionSpecifier(); 1662 1663 return HandleInvalidConversionSpecifier(FS.getArgIndex(), 1664 getLocationOfByte(CS.getStart()), 1665 startSpecifier, specifierLen, 1666 CS.getStart(), CS.getLength()); 1667} 1668 1669bool CheckScanfHandler::HandleScanfSpecifier( 1670 const analyze_scanf::ScanfSpecifier &FS, 1671 const char *startSpecifier, 1672 unsigned specifierLen) { 1673 1674 using namespace analyze_scanf; 1675 using namespace analyze_format_string; 1676 1677 const ScanfConversionSpecifier &CS = FS.getConversionSpecifier(); 1678 1679 // Handle case where '%' and '*' don't consume an argument. These shouldn't 1680 // be used to decide if we are using positional arguments consistently. 1681 if (FS.consumesDataArgument()) { 1682 if (atFirstArg) { 1683 atFirstArg = false; 1684 usesPositionalArgs = FS.usesPositionalArg(); 1685 } 1686 else if (usesPositionalArgs != FS.usesPositionalArg()) { 1687 // Cannot mix-and-match positional and non-positional arguments. 1688 S.Diag(getLocationOfByte(CS.getStart()), 1689 diag::warn_format_mix_positional_nonpositional_args) 1690 << getSpecifierRange(startSpecifier, specifierLen); 1691 return false; 1692 } 1693 } 1694 1695 // Check if the field with is non-zero. 1696 const OptionalAmount &Amt = FS.getFieldWidth(); 1697 if (Amt.getHowSpecified() == OptionalAmount::Constant) { 1698 if (Amt.getConstantAmount() == 0) { 1699 const CharSourceRange &R = getSpecifierRange(Amt.getStart(), 1700 Amt.getConstantLength()); 1701 S.Diag(getLocationOfByte(Amt.getStart()), 1702 diag::warn_scanf_nonzero_width) 1703 << R << FixItHint::CreateRemoval(R); 1704 } 1705 } 1706 1707 if (!FS.consumesDataArgument()) { 1708 // FIXME: Technically specifying a precision or field width here 1709 // makes no sense. Worth issuing a warning at some point. 1710 return true; 1711 } 1712 1713 // Consume the argument. 1714 unsigned argIndex = FS.getArgIndex(); 1715 if (argIndex < NumDataArgs) { 1716 // The check to see if the argIndex is valid will come later. 1717 // We set the bit here because we may exit early from this 1718 // function if we encounter some other error. 1719 CoveredArgs.set(argIndex); 1720 } 1721 1722 // Check the length modifier is valid with the given conversion specifier. 1723 const LengthModifier &LM = FS.getLengthModifier(); 1724 if (!FS.hasValidLengthModifier()) { 1725 S.Diag(getLocationOfByte(LM.getStart()), 1726 diag::warn_format_nonsensical_length) 1727 << LM.toString() << CS.toString() 1728 << getSpecifierRange(startSpecifier, specifierLen) 1729 << FixItHint::CreateRemoval(getSpecifierRange(LM.getStart(), 1730 LM.getLength())); 1731 } 1732 1733 // The remaining checks depend on the data arguments. 1734 if (HasVAListArg) 1735 return true; 1736 1737 if (!CheckNumArgs(FS, CS, startSpecifier, specifierLen, argIndex)) 1738 return false; 1739 1740 // FIXME: Check that the argument type matches the format specifier. 1741 1742 return true; 1743} 1744 1745void Sema::CheckFormatString(const StringLiteral *FExpr, 1746 const Expr *OrigFormatExpr, 1747 const CallExpr *TheCall, bool HasVAListArg, 1748 unsigned format_idx, unsigned firstDataArg, 1749 bool isPrintf) { 1750 1751 // CHECK: is the format string a wide literal? 1752 if (FExpr->isWide()) { 1753 Diag(FExpr->getLocStart(), 1754 diag::warn_format_string_is_wide_literal) 1755 << OrigFormatExpr->getSourceRange(); 1756 return; 1757 } 1758 1759 // Str - The format string. NOTE: this is NOT null-terminated! 1760 llvm::StringRef StrRef = FExpr->getString(); 1761 const char *Str = StrRef.data(); 1762 unsigned StrLen = StrRef.size(); 1763 1764 // CHECK: empty format string? 1765 if (StrLen == 0) { 1766 Diag(FExpr->getLocStart(), diag::warn_empty_format_string) 1767 << OrigFormatExpr->getSourceRange(); 1768 return; 1769 } 1770 1771 if (isPrintf) { 1772 CheckPrintfHandler H(*this, FExpr, OrigFormatExpr, firstDataArg, 1773 TheCall->getNumArgs() - firstDataArg, 1774 isa<ObjCStringLiteral>(OrigFormatExpr), Str, 1775 HasVAListArg, TheCall, format_idx); 1776 1777 if (!analyze_format_string::ParsePrintfString(H, Str, Str + StrLen)) 1778 H.DoneProcessing(); 1779 } 1780 else { 1781 CheckScanfHandler H(*this, FExpr, OrigFormatExpr, firstDataArg, 1782 TheCall->getNumArgs() - firstDataArg, 1783 isa<ObjCStringLiteral>(OrigFormatExpr), Str, 1784 HasVAListArg, TheCall, format_idx); 1785 1786 if (!analyze_format_string::ParseScanfString(H, Str, Str + StrLen)) 1787 H.DoneProcessing(); 1788 } 1789} 1790 1791//===--- CHECK: Return Address of Stack Variable --------------------------===// 1792 1793static DeclRefExpr* EvalVal(Expr *E); 1794static DeclRefExpr* EvalAddr(Expr* E); 1795 1796/// CheckReturnStackAddr - Check if a return statement returns the address 1797/// of a stack variable. 1798void 1799Sema::CheckReturnStackAddr(Expr *RetValExp, QualType lhsType, 1800 SourceLocation ReturnLoc) { 1801 1802 // Perform checking for returned stack addresses. 1803 if (lhsType->isPointerType() || lhsType->isBlockPointerType()) { 1804 if (DeclRefExpr *DR = EvalAddr(RetValExp)) 1805 Diag(DR->getLocStart(), diag::warn_ret_stack_addr) 1806 << DR->getDecl()->getDeclName() << RetValExp->getSourceRange(); 1807 1808 // Skip over implicit cast expressions when checking for block expressions. 1809 RetValExp = RetValExp->IgnoreParenCasts(); 1810 1811 if (BlockExpr *C = dyn_cast<BlockExpr>(RetValExp)) 1812 if (C->hasBlockDeclRefExprs()) 1813 Diag(C->getLocStart(), diag::err_ret_local_block) 1814 << C->getSourceRange(); 1815 1816 if (AddrLabelExpr *ALE = dyn_cast<AddrLabelExpr>(RetValExp)) 1817 Diag(ALE->getLocStart(), diag::warn_ret_addr_label) 1818 << ALE->getSourceRange(); 1819 1820 } else if (lhsType->isReferenceType()) { 1821 // Perform checking for stack values returned by reference. 1822 // Check for a reference to the stack 1823 if (DeclRefExpr *DR = EvalVal(RetValExp)) 1824 Diag(DR->getLocStart(), diag::warn_ret_stack_ref) 1825 << DR->getDecl()->getDeclName() << RetValExp->getSourceRange(); 1826 } 1827} 1828 1829/// EvalAddr - EvalAddr and EvalVal are mutually recursive functions that 1830/// check if the expression in a return statement evaluates to an address 1831/// to a location on the stack. The recursion is used to traverse the 1832/// AST of the return expression, with recursion backtracking when we 1833/// encounter a subexpression that (1) clearly does not lead to the address 1834/// of a stack variable or (2) is something we cannot determine leads to 1835/// the address of a stack variable based on such local checking. 1836/// 1837/// EvalAddr processes expressions that are pointers that are used as 1838/// references (and not L-values). EvalVal handles all other values. 1839/// At the base case of the recursion is a check for a DeclRefExpr* in 1840/// the refers to a stack variable. 1841/// 1842/// This implementation handles: 1843/// 1844/// * pointer-to-pointer casts 1845/// * implicit conversions from array references to pointers 1846/// * taking the address of fields 1847/// * arbitrary interplay between "&" and "*" operators 1848/// * pointer arithmetic from an address of a stack variable 1849/// * taking the address of an array element where the array is on the stack 1850static DeclRefExpr* EvalAddr(Expr *E) { 1851 // We should only be called for evaluating pointer expressions. 1852 assert((E->getType()->isAnyPointerType() || 1853 E->getType()->isBlockPointerType() || 1854 E->getType()->isObjCQualifiedIdType()) && 1855 "EvalAddr only works on pointers"); 1856 1857 // Our "symbolic interpreter" is just a dispatch off the currently 1858 // viewed AST node. We then recursively traverse the AST by calling 1859 // EvalAddr and EvalVal appropriately. 1860 switch (E->getStmtClass()) { 1861 case Stmt::ParenExprClass: 1862 // Ignore parentheses. 1863 return EvalAddr(cast<ParenExpr>(E)->getSubExpr()); 1864 1865 case Stmt::UnaryOperatorClass: { 1866 // The only unary operator that make sense to handle here 1867 // is AddrOf. All others don't make sense as pointers. 1868 UnaryOperator *U = cast<UnaryOperator>(E); 1869 1870 if (U->getOpcode() == UnaryOperator::AddrOf) 1871 return EvalVal(U->getSubExpr()); 1872 else 1873 return NULL; 1874 } 1875 1876 case Stmt::BinaryOperatorClass: { 1877 // Handle pointer arithmetic. All other binary operators are not valid 1878 // in this context. 1879 BinaryOperator *B = cast<BinaryOperator>(E); 1880 BinaryOperator::Opcode op = B->getOpcode(); 1881 1882 if (op != BinaryOperator::Add && op != BinaryOperator::Sub) 1883 return NULL; 1884 1885 Expr *Base = B->getLHS(); 1886 1887 // Determine which argument is the real pointer base. It could be 1888 // the RHS argument instead of the LHS. 1889 if (!Base->getType()->isPointerType()) Base = B->getRHS(); 1890 1891 assert (Base->getType()->isPointerType()); 1892 return EvalAddr(Base); 1893 } 1894 1895 // For conditional operators we need to see if either the LHS or RHS are 1896 // valid DeclRefExpr*s. If one of them is valid, we return it. 1897 case Stmt::ConditionalOperatorClass: { 1898 ConditionalOperator *C = cast<ConditionalOperator>(E); 1899 1900 // Handle the GNU extension for missing LHS. 1901 if (Expr *lhsExpr = C->getLHS()) 1902 if (DeclRefExpr* LHS = EvalAddr(lhsExpr)) 1903 return LHS; 1904 1905 return EvalAddr(C->getRHS()); 1906 } 1907 1908 // For casts, we need to handle conversions from arrays to 1909 // pointer values, and pointer-to-pointer conversions. 1910 case Stmt::ImplicitCastExprClass: 1911 case Stmt::CStyleCastExprClass: 1912 case Stmt::CXXFunctionalCastExprClass: { 1913 Expr* SubExpr = cast<CastExpr>(E)->getSubExpr(); 1914 QualType T = SubExpr->getType(); 1915 1916 if (SubExpr->getType()->isPointerType() || 1917 SubExpr->getType()->isBlockPointerType() || 1918 SubExpr->getType()->isObjCQualifiedIdType()) 1919 return EvalAddr(SubExpr); 1920 else if (T->isArrayType()) 1921 return EvalVal(SubExpr); 1922 else 1923 return 0; 1924 } 1925 1926 // C++ casts. For dynamic casts, static casts, and const casts, we 1927 // are always converting from a pointer-to-pointer, so we just blow 1928 // through the cast. In the case the dynamic cast doesn't fail (and 1929 // return NULL), we take the conservative route and report cases 1930 // where we return the address of a stack variable. For Reinterpre 1931 // FIXME: The comment about is wrong; we're not always converting 1932 // from pointer to pointer. I'm guessing that this code should also 1933 // handle references to objects. 1934 case Stmt::CXXStaticCastExprClass: 1935 case Stmt::CXXDynamicCastExprClass: 1936 case Stmt::CXXConstCastExprClass: 1937 case Stmt::CXXReinterpretCastExprClass: { 1938 Expr *S = cast<CXXNamedCastExpr>(E)->getSubExpr(); 1939 if (S->getType()->isPointerType() || S->getType()->isBlockPointerType()) 1940 return EvalAddr(S); 1941 else 1942 return NULL; 1943 } 1944 1945 // Everything else: we simply don't reason about them. 1946 default: 1947 return NULL; 1948 } 1949} 1950 1951 1952/// EvalVal - This function is complements EvalAddr in the mutual recursion. 1953/// See the comments for EvalAddr for more details. 1954static DeclRefExpr* EvalVal(Expr *E) { 1955do { 1956 // We should only be called for evaluating non-pointer expressions, or 1957 // expressions with a pointer type that are not used as references but instead 1958 // are l-values (e.g., DeclRefExpr with a pointer type). 1959 1960 // Our "symbolic interpreter" is just a dispatch off the currently 1961 // viewed AST node. We then recursively traverse the AST by calling 1962 // EvalAddr and EvalVal appropriately. 1963 switch (E->getStmtClass()) { 1964 case Stmt::ImplicitCastExprClass: { 1965 ImplicitCastExpr *IE = cast<ImplicitCastExpr>(E); 1966 if (IE->getCategory() == ImplicitCastExpr::LValue) { 1967 E = IE->getSubExpr(); 1968 continue; 1969 } 1970 return NULL; 1971 } 1972 1973 case Stmt::DeclRefExprClass: { 1974 // DeclRefExpr: the base case. When we hit a DeclRefExpr we are looking 1975 // at code that refers to a variable's name. We check if it has local 1976 // storage within the function, and if so, return the expression. 1977 DeclRefExpr *DR = cast<DeclRefExpr>(E); 1978 1979 if (VarDecl *V = dyn_cast<VarDecl>(DR->getDecl())) 1980 if (V->hasLocalStorage() && !V->getType()->isReferenceType()) return DR; 1981 1982 return NULL; 1983 } 1984 1985 case Stmt::ParenExprClass: { 1986 // Ignore parentheses. 1987 E = cast<ParenExpr>(E)->getSubExpr(); 1988 continue; 1989 } 1990 1991 case Stmt::UnaryOperatorClass: { 1992 // The only unary operator that make sense to handle here 1993 // is Deref. All others don't resolve to a "name." This includes 1994 // handling all sorts of rvalues passed to a unary operator. 1995 UnaryOperator *U = cast<UnaryOperator>(E); 1996 1997 if (U->getOpcode() == UnaryOperator::Deref) 1998 return EvalAddr(U->getSubExpr()); 1999 2000 return NULL; 2001 } 2002 2003 case Stmt::ArraySubscriptExprClass: { 2004 // Array subscripts are potential references to data on the stack. We 2005 // retrieve the DeclRefExpr* for the array variable if it indeed 2006 // has local storage. 2007 return EvalAddr(cast<ArraySubscriptExpr>(E)->getBase()); 2008 } 2009 2010 case Stmt::ConditionalOperatorClass: { 2011 // For conditional operators we need to see if either the LHS or RHS are 2012 // non-NULL DeclRefExpr's. If one is non-NULL, we return it. 2013 ConditionalOperator *C = cast<ConditionalOperator>(E); 2014 2015 // Handle the GNU extension for missing LHS. 2016 if (Expr *lhsExpr = C->getLHS()) 2017 if (DeclRefExpr *LHS = EvalVal(lhsExpr)) 2018 return LHS; 2019 2020 return EvalVal(C->getRHS()); 2021 } 2022 2023 // Accesses to members are potential references to data on the stack. 2024 case Stmt::MemberExprClass: { 2025 MemberExpr *M = cast<MemberExpr>(E); 2026 2027 // Check for indirect access. We only want direct field accesses. 2028 if (!M->isArrow()) 2029 return EvalVal(M->getBase()); 2030 else 2031 return NULL; 2032 } 2033 2034 // Everything else: we simply don't reason about them. 2035 default: 2036 return NULL; 2037 } 2038} while (true); 2039} 2040 2041//===--- CHECK: Floating-Point comparisons (-Wfloat-equal) ---------------===// 2042 2043/// Check for comparisons of floating point operands using != and ==. 2044/// Issue a warning if these are no self-comparisons, as they are not likely 2045/// to do what the programmer intended. 2046void Sema::CheckFloatComparison(SourceLocation loc, Expr* lex, Expr *rex) { 2047 bool EmitWarning = true; 2048 2049 Expr* LeftExprSansParen = lex->IgnoreParens(); 2050 Expr* RightExprSansParen = rex->IgnoreParens(); 2051 2052 // Special case: check for x == x (which is OK). 2053 // Do not emit warnings for such cases. 2054 if (DeclRefExpr* DRL = dyn_cast<DeclRefExpr>(LeftExprSansParen)) 2055 if (DeclRefExpr* DRR = dyn_cast<DeclRefExpr>(RightExprSansParen)) 2056 if (DRL->getDecl() == DRR->getDecl()) 2057 EmitWarning = false; 2058 2059 2060 // Special case: check for comparisons against literals that can be exactly 2061 // represented by APFloat. In such cases, do not emit a warning. This 2062 // is a heuristic: often comparison against such literals are used to 2063 // detect if a value in a variable has not changed. This clearly can 2064 // lead to false negatives. 2065 if (EmitWarning) { 2066 if (FloatingLiteral* FLL = dyn_cast<FloatingLiteral>(LeftExprSansParen)) { 2067 if (FLL->isExact()) 2068 EmitWarning = false; 2069 } else 2070 if (FloatingLiteral* FLR = dyn_cast<FloatingLiteral>(RightExprSansParen)){ 2071 if (FLR->isExact()) 2072 EmitWarning = false; 2073 } 2074 } 2075 2076 // Check for comparisons with builtin types. 2077 if (EmitWarning) 2078 if (CallExpr* CL = dyn_cast<CallExpr>(LeftExprSansParen)) 2079 if (CL->isBuiltinCall(Context)) 2080 EmitWarning = false; 2081 2082 if (EmitWarning) 2083 if (CallExpr* CR = dyn_cast<CallExpr>(RightExprSansParen)) 2084 if (CR->isBuiltinCall(Context)) 2085 EmitWarning = false; 2086 2087 // Emit the diagnostic. 2088 if (EmitWarning) 2089 Diag(loc, diag::warn_floatingpoint_eq) 2090 << lex->getSourceRange() << rex->getSourceRange(); 2091} 2092 2093//===--- CHECK: Integer mixed-sign comparisons (-Wsign-compare) --------===// 2094//===--- CHECK: Lossy implicit conversions (-Wconversion) --------------===// 2095 2096namespace { 2097 2098/// Structure recording the 'active' range of an integer-valued 2099/// expression. 2100struct IntRange { 2101 /// The number of bits active in the int. 2102 unsigned Width; 2103 2104 /// True if the int is known not to have negative values. 2105 bool NonNegative; 2106 2107 IntRange(unsigned Width, bool NonNegative) 2108 : Width(Width), NonNegative(NonNegative) 2109 {} 2110 2111 // Returns the range of the bool type. 2112 static IntRange forBoolType() { 2113 return IntRange(1, true); 2114 } 2115 2116 // Returns the range of an integral type. 2117 static IntRange forType(ASTContext &C, QualType T) { 2118 return forCanonicalType(C, T->getCanonicalTypeInternal().getTypePtr()); 2119 } 2120 2121 // Returns the range of an integeral type based on its canonical 2122 // representation. 2123 static IntRange forCanonicalType(ASTContext &C, const Type *T) { 2124 assert(T->isCanonicalUnqualified()); 2125 2126 if (const VectorType *VT = dyn_cast<VectorType>(T)) 2127 T = VT->getElementType().getTypePtr(); 2128 if (const ComplexType *CT = dyn_cast<ComplexType>(T)) 2129 T = CT->getElementType().getTypePtr(); 2130 2131 if (const EnumType *ET = dyn_cast<EnumType>(T)) { 2132 EnumDecl *Enum = ET->getDecl(); 2133 unsigned NumPositive = Enum->getNumPositiveBits(); 2134 unsigned NumNegative = Enum->getNumNegativeBits(); 2135 2136 return IntRange(std::max(NumPositive, NumNegative), NumNegative == 0); 2137 } 2138 2139 const BuiltinType *BT = cast<BuiltinType>(T); 2140 assert(BT->isInteger()); 2141 2142 return IntRange(C.getIntWidth(QualType(T, 0)), BT->isUnsignedInteger()); 2143 } 2144 2145 // Returns the supremum of two ranges: i.e. their conservative merge. 2146 static IntRange join(IntRange L, IntRange R) { 2147 return IntRange(std::max(L.Width, R.Width), 2148 L.NonNegative && R.NonNegative); 2149 } 2150 2151 // Returns the infinum of two ranges: i.e. their aggressive merge. 2152 static IntRange meet(IntRange L, IntRange R) { 2153 return IntRange(std::min(L.Width, R.Width), 2154 L.NonNegative || R.NonNegative); 2155 } 2156}; 2157 2158IntRange GetValueRange(ASTContext &C, llvm::APSInt &value, unsigned MaxWidth) { 2159 if (value.isSigned() && value.isNegative()) 2160 return IntRange(value.getMinSignedBits(), false); 2161 2162 if (value.getBitWidth() > MaxWidth) 2163 value.trunc(MaxWidth); 2164 2165 // isNonNegative() just checks the sign bit without considering 2166 // signedness. 2167 return IntRange(value.getActiveBits(), true); 2168} 2169 2170IntRange GetValueRange(ASTContext &C, APValue &result, QualType Ty, 2171 unsigned MaxWidth) { 2172 if (result.isInt()) 2173 return GetValueRange(C, result.getInt(), MaxWidth); 2174 2175 if (result.isVector()) { 2176 IntRange R = GetValueRange(C, result.getVectorElt(0), Ty, MaxWidth); 2177 for (unsigned i = 1, e = result.getVectorLength(); i != e; ++i) { 2178 IntRange El = GetValueRange(C, result.getVectorElt(i), Ty, MaxWidth); 2179 R = IntRange::join(R, El); 2180 } 2181 return R; 2182 } 2183 2184 if (result.isComplexInt()) { 2185 IntRange R = GetValueRange(C, result.getComplexIntReal(), MaxWidth); 2186 IntRange I = GetValueRange(C, result.getComplexIntImag(), MaxWidth); 2187 return IntRange::join(R, I); 2188 } 2189 2190 // This can happen with lossless casts to intptr_t of "based" lvalues. 2191 // Assume it might use arbitrary bits. 2192 // FIXME: The only reason we need to pass the type in here is to get 2193 // the sign right on this one case. It would be nice if APValue 2194 // preserved this. 2195 assert(result.isLValue()); 2196 return IntRange(MaxWidth, Ty->isUnsignedIntegerType()); 2197} 2198 2199/// Pseudo-evaluate the given integer expression, estimating the 2200/// range of values it might take. 2201/// 2202/// \param MaxWidth - the width to which the value will be truncated 2203IntRange GetExprRange(ASTContext &C, Expr *E, unsigned MaxWidth) { 2204 E = E->IgnoreParens(); 2205 2206 // Try a full evaluation first. 2207 Expr::EvalResult result; 2208 if (E->Evaluate(result, C)) 2209 return GetValueRange(C, result.Val, E->getType(), MaxWidth); 2210 2211 // I think we only want to look through implicit casts here; if the 2212 // user has an explicit widening cast, we should treat the value as 2213 // being of the new, wider type. 2214 if (ImplicitCastExpr *CE = dyn_cast<ImplicitCastExpr>(E)) { 2215 if (CE->getCastKind() == CastExpr::CK_NoOp) 2216 return GetExprRange(C, CE->getSubExpr(), MaxWidth); 2217 2218 IntRange OutputTypeRange = IntRange::forType(C, CE->getType()); 2219 2220 bool isIntegerCast = (CE->getCastKind() == CastExpr::CK_IntegralCast); 2221 if (!isIntegerCast && CE->getCastKind() == CastExpr::CK_Unknown) 2222 isIntegerCast = CE->getSubExpr()->getType()->isIntegerType(); 2223 2224 // Assume that non-integer casts can span the full range of the type. 2225 if (!isIntegerCast) 2226 return OutputTypeRange; 2227 2228 IntRange SubRange 2229 = GetExprRange(C, CE->getSubExpr(), 2230 std::min(MaxWidth, OutputTypeRange.Width)); 2231 2232 // Bail out if the subexpr's range is as wide as the cast type. 2233 if (SubRange.Width >= OutputTypeRange.Width) 2234 return OutputTypeRange; 2235 2236 // Otherwise, we take the smaller width, and we're non-negative if 2237 // either the output type or the subexpr is. 2238 return IntRange(SubRange.Width, 2239 SubRange.NonNegative || OutputTypeRange.NonNegative); 2240 } 2241 2242 if (ConditionalOperator *CO = dyn_cast<ConditionalOperator>(E)) { 2243 // If we can fold the condition, just take that operand. 2244 bool CondResult; 2245 if (CO->getCond()->EvaluateAsBooleanCondition(CondResult, C)) 2246 return GetExprRange(C, CondResult ? CO->getTrueExpr() 2247 : CO->getFalseExpr(), 2248 MaxWidth); 2249 2250 // Otherwise, conservatively merge. 2251 IntRange L = GetExprRange(C, CO->getTrueExpr(), MaxWidth); 2252 IntRange R = GetExprRange(C, CO->getFalseExpr(), MaxWidth); 2253 return IntRange::join(L, R); 2254 } 2255 2256 if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) { 2257 switch (BO->getOpcode()) { 2258 2259 // Boolean-valued operations are single-bit and positive. 2260 case BinaryOperator::LAnd: 2261 case BinaryOperator::LOr: 2262 case BinaryOperator::LT: 2263 case BinaryOperator::GT: 2264 case BinaryOperator::LE: 2265 case BinaryOperator::GE: 2266 case BinaryOperator::EQ: 2267 case BinaryOperator::NE: 2268 return IntRange::forBoolType(); 2269 2270 // The type of these compound assignments is the type of the LHS, 2271 // so the RHS is not necessarily an integer. 2272 case BinaryOperator::MulAssign: 2273 case BinaryOperator::DivAssign: 2274 case BinaryOperator::RemAssign: 2275 case BinaryOperator::AddAssign: 2276 case BinaryOperator::SubAssign: 2277 return IntRange::forType(C, E->getType()); 2278 2279 // Operations with opaque sources are black-listed. 2280 case BinaryOperator::PtrMemD: 2281 case BinaryOperator::PtrMemI: 2282 return IntRange::forType(C, E->getType()); 2283 2284 // Bitwise-and uses the *infinum* of the two source ranges. 2285 case BinaryOperator::And: 2286 case BinaryOperator::AndAssign: 2287 return IntRange::meet(GetExprRange(C, BO->getLHS(), MaxWidth), 2288 GetExprRange(C, BO->getRHS(), MaxWidth)); 2289 2290 // Left shift gets black-listed based on a judgement call. 2291 case BinaryOperator::Shl: 2292 // ...except that we want to treat '1 << (blah)' as logically 2293 // positive. It's an important idiom. 2294 if (IntegerLiteral *I 2295 = dyn_cast<IntegerLiteral>(BO->getLHS()->IgnoreParenCasts())) { 2296 if (I->getValue() == 1) { 2297 IntRange R = IntRange::forType(C, E->getType()); 2298 return IntRange(R.Width, /*NonNegative*/ true); 2299 } 2300 } 2301 // fallthrough 2302 2303 case BinaryOperator::ShlAssign: 2304 return IntRange::forType(C, E->getType()); 2305 2306 // Right shift by a constant can narrow its left argument. 2307 case BinaryOperator::Shr: 2308 case BinaryOperator::ShrAssign: { 2309 IntRange L = GetExprRange(C, BO->getLHS(), MaxWidth); 2310 2311 // If the shift amount is a positive constant, drop the width by 2312 // that much. 2313 llvm::APSInt shift; 2314 if (BO->getRHS()->isIntegerConstantExpr(shift, C) && 2315 shift.isNonNegative()) { 2316 unsigned zext = shift.getZExtValue(); 2317 if (zext >= L.Width) 2318 L.Width = (L.NonNegative ? 0 : 1); 2319 else 2320 L.Width -= zext; 2321 } 2322 2323 return L; 2324 } 2325 2326 // Comma acts as its right operand. 2327 case BinaryOperator::Comma: 2328 return GetExprRange(C, BO->getRHS(), MaxWidth); 2329 2330 // Black-list pointer subtractions. 2331 case BinaryOperator::Sub: 2332 if (BO->getLHS()->getType()->isPointerType()) 2333 return IntRange::forType(C, E->getType()); 2334 // fallthrough 2335 2336 default: 2337 break; 2338 } 2339 2340 // Treat every other operator as if it were closed on the 2341 // narrowest type that encompasses both operands. 2342 IntRange L = GetExprRange(C, BO->getLHS(), MaxWidth); 2343 IntRange R = GetExprRange(C, BO->getRHS(), MaxWidth); 2344 return IntRange::join(L, R); 2345 } 2346 2347 if (UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) { 2348 switch (UO->getOpcode()) { 2349 // Boolean-valued operations are white-listed. 2350 case UnaryOperator::LNot: 2351 return IntRange::forBoolType(); 2352 2353 // Operations with opaque sources are black-listed. 2354 case UnaryOperator::Deref: 2355 case UnaryOperator::AddrOf: // should be impossible 2356 return IntRange::forType(C, E->getType()); 2357 2358 default: 2359 return GetExprRange(C, UO->getSubExpr(), MaxWidth); 2360 } 2361 } 2362 2363 if (dyn_cast<OffsetOfExpr>(E)) { 2364 IntRange::forType(C, E->getType()); 2365 } 2366 2367 FieldDecl *BitField = E->getBitField(); 2368 if (BitField) { 2369 llvm::APSInt BitWidthAP = BitField->getBitWidth()->EvaluateAsInt(C); 2370 unsigned BitWidth = BitWidthAP.getZExtValue(); 2371 2372 return IntRange(BitWidth, BitField->getType()->isUnsignedIntegerType()); 2373 } 2374 2375 return IntRange::forType(C, E->getType()); 2376} 2377 2378IntRange GetExprRange(ASTContext &C, Expr *E) { 2379 return GetExprRange(C, E, C.getIntWidth(E->getType())); 2380} 2381 2382/// Checks whether the given value, which currently has the given 2383/// source semantics, has the same value when coerced through the 2384/// target semantics. 2385bool IsSameFloatAfterCast(const llvm::APFloat &value, 2386 const llvm::fltSemantics &Src, 2387 const llvm::fltSemantics &Tgt) { 2388 llvm::APFloat truncated = value; 2389 2390 bool ignored; 2391 truncated.convert(Src, llvm::APFloat::rmNearestTiesToEven, &ignored); 2392 truncated.convert(Tgt, llvm::APFloat::rmNearestTiesToEven, &ignored); 2393 2394 return truncated.bitwiseIsEqual(value); 2395} 2396 2397/// Checks whether the given value, which currently has the given 2398/// source semantics, has the same value when coerced through the 2399/// target semantics. 2400/// 2401/// The value might be a vector of floats (or a complex number). 2402bool IsSameFloatAfterCast(const APValue &value, 2403 const llvm::fltSemantics &Src, 2404 const llvm::fltSemantics &Tgt) { 2405 if (value.isFloat()) 2406 return IsSameFloatAfterCast(value.getFloat(), Src, Tgt); 2407 2408 if (value.isVector()) { 2409 for (unsigned i = 0, e = value.getVectorLength(); i != e; ++i) 2410 if (!IsSameFloatAfterCast(value.getVectorElt(i), Src, Tgt)) 2411 return false; 2412 return true; 2413 } 2414 2415 assert(value.isComplexFloat()); 2416 return (IsSameFloatAfterCast(value.getComplexFloatReal(), Src, Tgt) && 2417 IsSameFloatAfterCast(value.getComplexFloatImag(), Src, Tgt)); 2418} 2419 2420void AnalyzeImplicitConversions(Sema &S, Expr *E); 2421 2422bool IsZero(Sema &S, Expr *E) { 2423 llvm::APSInt Value; 2424 return E->isIntegerConstantExpr(Value, S.Context) && Value == 0; 2425} 2426 2427void CheckTrivialUnsignedComparison(Sema &S, BinaryOperator *E) { 2428 BinaryOperator::Opcode op = E->getOpcode(); 2429 if (op == BinaryOperator::LT && IsZero(S, E->getRHS())) { 2430 S.Diag(E->getOperatorLoc(), diag::warn_lunsigned_always_true_comparison) 2431 << "< 0" << "false" 2432 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); 2433 } else if (op == BinaryOperator::GE && IsZero(S, E->getRHS())) { 2434 S.Diag(E->getOperatorLoc(), diag::warn_lunsigned_always_true_comparison) 2435 << ">= 0" << "true" 2436 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); 2437 } else if (op == BinaryOperator::GT && IsZero(S, E->getLHS())) { 2438 S.Diag(E->getOperatorLoc(), diag::warn_runsigned_always_true_comparison) 2439 << "0 >" << "false" 2440 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); 2441 } else if (op == BinaryOperator::LE && IsZero(S, E->getLHS())) { 2442 S.Diag(E->getOperatorLoc(), diag::warn_runsigned_always_true_comparison) 2443 << "0 <=" << "true" 2444 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); 2445 } 2446} 2447 2448/// Analyze the operands of the given comparison. Implements the 2449/// fallback case from AnalyzeComparison. 2450void AnalyzeImpConvsInComparison(Sema &S, BinaryOperator *E) { 2451 AnalyzeImplicitConversions(S, E->getLHS()); 2452 AnalyzeImplicitConversions(S, E->getRHS()); 2453} 2454 2455/// \brief Implements -Wsign-compare. 2456/// 2457/// \param lex the left-hand expression 2458/// \param rex the right-hand expression 2459/// \param OpLoc the location of the joining operator 2460/// \param BinOpc binary opcode or 0 2461void AnalyzeComparison(Sema &S, BinaryOperator *E) { 2462 // The type the comparison is being performed in. 2463 QualType T = E->getLHS()->getType(); 2464 assert(S.Context.hasSameUnqualifiedType(T, E->getRHS()->getType()) 2465 && "comparison with mismatched types"); 2466 2467 // We don't do anything special if this isn't an unsigned integral 2468 // comparison: we're only interested in integral comparisons, and 2469 // signed comparisons only happen in cases we don't care to warn about. 2470 if (!T->hasUnsignedIntegerRepresentation()) 2471 return AnalyzeImpConvsInComparison(S, E); 2472 2473 Expr *lex = E->getLHS()->IgnoreParenImpCasts(); 2474 Expr *rex = E->getRHS()->IgnoreParenImpCasts(); 2475 2476 // Check to see if one of the (unmodified) operands is of different 2477 // signedness. 2478 Expr *signedOperand, *unsignedOperand; 2479 if (lex->getType()->hasSignedIntegerRepresentation()) { 2480 assert(!rex->getType()->hasSignedIntegerRepresentation() && 2481 "unsigned comparison between two signed integer expressions?"); 2482 signedOperand = lex; 2483 unsignedOperand = rex; 2484 } else if (rex->getType()->hasSignedIntegerRepresentation()) { 2485 signedOperand = rex; 2486 unsignedOperand = lex; 2487 } else { 2488 CheckTrivialUnsignedComparison(S, E); 2489 return AnalyzeImpConvsInComparison(S, E); 2490 } 2491 2492 // Otherwise, calculate the effective range of the signed operand. 2493 IntRange signedRange = GetExprRange(S.Context, signedOperand); 2494 2495 // Go ahead and analyze implicit conversions in the operands. Note 2496 // that we skip the implicit conversions on both sides. 2497 AnalyzeImplicitConversions(S, lex); 2498 AnalyzeImplicitConversions(S, rex); 2499 2500 // If the signed range is non-negative, -Wsign-compare won't fire, 2501 // but we should still check for comparisons which are always true 2502 // or false. 2503 if (signedRange.NonNegative) 2504 return CheckTrivialUnsignedComparison(S, E); 2505 2506 // For (in)equality comparisons, if the unsigned operand is a 2507 // constant which cannot collide with a overflowed signed operand, 2508 // then reinterpreting the signed operand as unsigned will not 2509 // change the result of the comparison. 2510 if (E->isEqualityOp()) { 2511 unsigned comparisonWidth = S.Context.getIntWidth(T); 2512 IntRange unsignedRange = GetExprRange(S.Context, unsignedOperand); 2513 2514 // We should never be unable to prove that the unsigned operand is 2515 // non-negative. 2516 assert(unsignedRange.NonNegative && "unsigned range includes negative?"); 2517 2518 if (unsignedRange.Width < comparisonWidth) 2519 return; 2520 } 2521 2522 S.Diag(E->getOperatorLoc(), diag::warn_mixed_sign_comparison) 2523 << lex->getType() << rex->getType() 2524 << lex->getSourceRange() << rex->getSourceRange(); 2525} 2526 2527/// Diagnose an implicit cast; purely a helper for CheckImplicitConversion. 2528void DiagnoseImpCast(Sema &S, Expr *E, QualType T, unsigned diag) { 2529 S.Diag(E->getExprLoc(), diag) << E->getType() << T << E->getSourceRange(); 2530} 2531 2532void CheckImplicitConversion(Sema &S, Expr *E, QualType T, 2533 bool *ICContext = 0) { 2534 if (E->isTypeDependent() || E->isValueDependent()) return; 2535 2536 const Type *Source = S.Context.getCanonicalType(E->getType()).getTypePtr(); 2537 const Type *Target = S.Context.getCanonicalType(T).getTypePtr(); 2538 if (Source == Target) return; 2539 if (Target->isDependentType()) return; 2540 2541 // Never diagnose implicit casts to bool. 2542 if (Target->isSpecificBuiltinType(BuiltinType::Bool)) 2543 return; 2544 2545 // Strip vector types. 2546 if (isa<VectorType>(Source)) { 2547 if (!isa<VectorType>(Target)) 2548 return DiagnoseImpCast(S, E, T, diag::warn_impcast_vector_scalar); 2549 2550 Source = cast<VectorType>(Source)->getElementType().getTypePtr(); 2551 Target = cast<VectorType>(Target)->getElementType().getTypePtr(); 2552 } 2553 2554 // Strip complex types. 2555 if (isa<ComplexType>(Source)) { 2556 if (!isa<ComplexType>(Target)) 2557 return DiagnoseImpCast(S, E, T, diag::warn_impcast_complex_scalar); 2558 2559 Source = cast<ComplexType>(Source)->getElementType().getTypePtr(); 2560 Target = cast<ComplexType>(Target)->getElementType().getTypePtr(); 2561 } 2562 2563 const BuiltinType *SourceBT = dyn_cast<BuiltinType>(Source); 2564 const BuiltinType *TargetBT = dyn_cast<BuiltinType>(Target); 2565 2566 // If the source is floating point... 2567 if (SourceBT && SourceBT->isFloatingPoint()) { 2568 // ...and the target is floating point... 2569 if (TargetBT && TargetBT->isFloatingPoint()) { 2570 // ...then warn if we're dropping FP rank. 2571 2572 // Builtin FP kinds are ordered by increasing FP rank. 2573 if (SourceBT->getKind() > TargetBT->getKind()) { 2574 // Don't warn about float constants that are precisely 2575 // representable in the target type. 2576 Expr::EvalResult result; 2577 if (E->Evaluate(result, S.Context)) { 2578 // Value might be a float, a float vector, or a float complex. 2579 if (IsSameFloatAfterCast(result.Val, 2580 S.Context.getFloatTypeSemantics(QualType(TargetBT, 0)), 2581 S.Context.getFloatTypeSemantics(QualType(SourceBT, 0)))) 2582 return; 2583 } 2584 2585 DiagnoseImpCast(S, E, T, diag::warn_impcast_float_precision); 2586 } 2587 return; 2588 } 2589 2590 // If the target is integral, always warn. 2591 if ((TargetBT && TargetBT->isInteger())) 2592 // TODO: don't warn for integer values? 2593 DiagnoseImpCast(S, E, T, diag::warn_impcast_float_integer); 2594 2595 return; 2596 } 2597 2598 if (!Source->isIntegerType() || !Target->isIntegerType()) 2599 return; 2600 2601 IntRange SourceRange = GetExprRange(S.Context, E); 2602 IntRange TargetRange = IntRange::forCanonicalType(S.Context, Target); 2603 2604 if (SourceRange.Width > TargetRange.Width) { 2605 // People want to build with -Wshorten-64-to-32 and not -Wconversion 2606 // and by god we'll let them. 2607 if (SourceRange.Width == 64 && TargetRange.Width == 32) 2608 return DiagnoseImpCast(S, E, T, diag::warn_impcast_integer_64_32); 2609 return DiagnoseImpCast(S, E, T, diag::warn_impcast_integer_precision); 2610 } 2611 2612 if ((TargetRange.NonNegative && !SourceRange.NonNegative) || 2613 (!TargetRange.NonNegative && SourceRange.NonNegative && 2614 SourceRange.Width == TargetRange.Width)) { 2615 unsigned DiagID = diag::warn_impcast_integer_sign; 2616 2617 // Traditionally, gcc has warned about this under -Wsign-compare. 2618 // We also want to warn about it in -Wconversion. 2619 // So if -Wconversion is off, use a completely identical diagnostic 2620 // in the sign-compare group. 2621 // The conditional-checking code will 2622 if (ICContext) { 2623 DiagID = diag::warn_impcast_integer_sign_conditional; 2624 *ICContext = true; 2625 } 2626 2627 return DiagnoseImpCast(S, E, T, DiagID); 2628 } 2629 2630 return; 2631} 2632 2633void CheckConditionalOperator(Sema &S, ConditionalOperator *E, QualType T); 2634 2635void CheckConditionalOperand(Sema &S, Expr *E, QualType T, 2636 bool &ICContext) { 2637 E = E->IgnoreParenImpCasts(); 2638 2639 if (isa<ConditionalOperator>(E)) 2640 return CheckConditionalOperator(S, cast<ConditionalOperator>(E), T); 2641 2642 AnalyzeImplicitConversions(S, E); 2643 if (E->getType() != T) 2644 return CheckImplicitConversion(S, E, T, &ICContext); 2645 return; 2646} 2647 2648void CheckConditionalOperator(Sema &S, ConditionalOperator *E, QualType T) { 2649 AnalyzeImplicitConversions(S, E->getCond()); 2650 2651 bool Suspicious = false; 2652 CheckConditionalOperand(S, E->getTrueExpr(), T, Suspicious); 2653 CheckConditionalOperand(S, E->getFalseExpr(), T, Suspicious); 2654 2655 // If -Wconversion would have warned about either of the candidates 2656 // for a signedness conversion to the context type... 2657 if (!Suspicious) return; 2658 2659 // ...but it's currently ignored... 2660 if (S.Diags.getDiagnosticLevel(diag::warn_impcast_integer_sign_conditional)) 2661 return; 2662 2663 // ...and -Wsign-compare isn't... 2664 if (!S.Diags.getDiagnosticLevel(diag::warn_mixed_sign_conditional)) 2665 return; 2666 2667 // ...then check whether it would have warned about either of the 2668 // candidates for a signedness conversion to the condition type. 2669 if (E->getType() != T) { 2670 Suspicious = false; 2671 CheckImplicitConversion(S, E->getTrueExpr()->IgnoreParenImpCasts(), 2672 E->getType(), &Suspicious); 2673 if (!Suspicious) 2674 CheckImplicitConversion(S, E->getFalseExpr()->IgnoreParenImpCasts(), 2675 E->getType(), &Suspicious); 2676 if (!Suspicious) 2677 return; 2678 } 2679 2680 // If so, emit a diagnostic under -Wsign-compare. 2681 Expr *lex = E->getTrueExpr()->IgnoreParenImpCasts(); 2682 Expr *rex = E->getFalseExpr()->IgnoreParenImpCasts(); 2683 S.Diag(E->getQuestionLoc(), diag::warn_mixed_sign_conditional) 2684 << lex->getType() << rex->getType() 2685 << lex->getSourceRange() << rex->getSourceRange(); 2686} 2687 2688/// AnalyzeImplicitConversions - Find and report any interesting 2689/// implicit conversions in the given expression. There are a couple 2690/// of competing diagnostics here, -Wconversion and -Wsign-compare. 2691void AnalyzeImplicitConversions(Sema &S, Expr *OrigE) { 2692 QualType T = OrigE->getType(); 2693 Expr *E = OrigE->IgnoreParenImpCasts(); 2694 2695 // For conditional operators, we analyze the arguments as if they 2696 // were being fed directly into the output. 2697 if (isa<ConditionalOperator>(E)) { 2698 ConditionalOperator *CO = cast<ConditionalOperator>(E); 2699 CheckConditionalOperator(S, CO, T); 2700 return; 2701 } 2702 2703 // Go ahead and check any implicit conversions we might have skipped. 2704 // The non-canonical typecheck is just an optimization; 2705 // CheckImplicitConversion will filter out dead implicit conversions. 2706 if (E->getType() != T) 2707 CheckImplicitConversion(S, E, T); 2708 2709 // Now continue drilling into this expression. 2710 2711 // Skip past explicit casts. 2712 if (isa<ExplicitCastExpr>(E)) { 2713 E = cast<ExplicitCastExpr>(E)->getSubExpr()->IgnoreParenImpCasts(); 2714 return AnalyzeImplicitConversions(S, E); 2715 } 2716 2717 // Do a somewhat different check with comparison operators. 2718 if (isa<BinaryOperator>(E) && cast<BinaryOperator>(E)->isComparisonOp()) 2719 return AnalyzeComparison(S, cast<BinaryOperator>(E)); 2720 2721 // These break the otherwise-useful invariant below. Fortunately, 2722 // we don't really need to recurse into them, because any internal 2723 // expressions should have been analyzed already when they were 2724 // built into statements. 2725 if (isa<StmtExpr>(E)) return; 2726 2727 // Don't descend into unevaluated contexts. 2728 if (isa<SizeOfAlignOfExpr>(E)) return; 2729 2730 // Now just recurse over the expression's children. 2731 for (Stmt::child_iterator I = E->child_begin(), IE = E->child_end(); 2732 I != IE; ++I) 2733 AnalyzeImplicitConversions(S, cast<Expr>(*I)); 2734} 2735 2736} // end anonymous namespace 2737 2738/// Diagnoses "dangerous" implicit conversions within the given 2739/// expression (which is a full expression). Implements -Wconversion 2740/// and -Wsign-compare. 2741void Sema::CheckImplicitConversions(Expr *E) { 2742 // Don't diagnose in unevaluated contexts. 2743 if (ExprEvalContexts.back().Context == Sema::Unevaluated) 2744 return; 2745 2746 // Don't diagnose for value- or type-dependent expressions. 2747 if (E->isTypeDependent() || E->isValueDependent()) 2748 return; 2749 2750 AnalyzeImplicitConversions(*this, E); 2751} 2752 2753/// CheckParmsForFunctionDef - Check that the parameters of the given 2754/// function are appropriate for the definition of a function. This 2755/// takes care of any checks that cannot be performed on the 2756/// declaration itself, e.g., that the types of each of the function 2757/// parameters are complete. 2758bool Sema::CheckParmsForFunctionDef(FunctionDecl *FD) { 2759 bool HasInvalidParm = false; 2760 for (unsigned p = 0, NumParams = FD->getNumParams(); p < NumParams; ++p) { 2761 ParmVarDecl *Param = FD->getParamDecl(p); 2762 2763 // C99 6.7.5.3p4: the parameters in a parameter type list in a 2764 // function declarator that is part of a function definition of 2765 // that function shall not have incomplete type. 2766 // 2767 // This is also C++ [dcl.fct]p6. 2768 if (!Param->isInvalidDecl() && 2769 RequireCompleteType(Param->getLocation(), Param->getType(), 2770 diag::err_typecheck_decl_incomplete_type)) { 2771 Param->setInvalidDecl(); 2772 HasInvalidParm = true; 2773 } 2774 2775 // C99 6.9.1p5: If the declarator includes a parameter type list, the 2776 // declaration of each parameter shall include an identifier. 2777 if (Param->getIdentifier() == 0 && 2778 !Param->isImplicit() && 2779 !getLangOptions().CPlusPlus) 2780 Diag(Param->getLocation(), diag::err_parameter_name_omitted); 2781 2782 // C99 6.7.5.3p12: 2783 // If the function declarator is not part of a definition of that 2784 // function, parameters may have incomplete type and may use the [*] 2785 // notation in their sequences of declarator specifiers to specify 2786 // variable length array types. 2787 QualType PType = Param->getOriginalType(); 2788 if (const ArrayType *AT = Context.getAsArrayType(PType)) { 2789 if (AT->getSizeModifier() == ArrayType::Star) { 2790 // FIXME: This diagnosic should point the the '[*]' if source-location 2791 // information is added for it. 2792 Diag(Param->getLocation(), diag::err_array_star_in_function_definition); 2793 } 2794 } 2795 } 2796 2797 return HasInvalidParm; 2798} 2799 2800/// CheckCastAlign - Implements -Wcast-align, which warns when a 2801/// pointer cast increases the alignment requirements. 2802void Sema::CheckCastAlign(Expr *Op, QualType T, SourceRange TRange) { 2803 // This is actually a lot of work to potentially be doing on every 2804 // cast; don't do it if we're ignoring -Wcast_align (as is the default). 2805 if (getDiagnostics().getDiagnosticLevel(diag::warn_cast_align) 2806 == Diagnostic::Ignored) 2807 return; 2808 2809 // Ignore dependent types. 2810 if (T->isDependentType() || Op->getType()->isDependentType()) 2811 return; 2812 2813 // Require that the destination be a pointer type. 2814 const PointerType *DestPtr = T->getAs<PointerType>(); 2815 if (!DestPtr) return; 2816 2817 // If the destination has alignment 1, we're done. 2818 QualType DestPointee = DestPtr->getPointeeType(); 2819 if (DestPointee->isIncompleteType()) return; 2820 CharUnits DestAlign = Context.getTypeAlignInChars(DestPointee); 2821 if (DestAlign.isOne()) return; 2822 2823 // Require that the source be a pointer type. 2824 const PointerType *SrcPtr = Op->getType()->getAs<PointerType>(); 2825 if (!SrcPtr) return; 2826 QualType SrcPointee = SrcPtr->getPointeeType(); 2827 2828 // Whitelist casts from cv void*. We already implicitly 2829 // whitelisted casts to cv void*, since they have alignment 1. 2830 // Also whitelist casts involving incomplete types, which implicitly 2831 // includes 'void'. 2832 if (SrcPointee->isIncompleteType()) return; 2833 2834 CharUnits SrcAlign = Context.getTypeAlignInChars(SrcPointee); 2835 if (SrcAlign >= DestAlign) return; 2836 2837 Diag(TRange.getBegin(), diag::warn_cast_align) 2838 << Op->getType() << T 2839 << static_cast<unsigned>(SrcAlign.getQuantity()) 2840 << static_cast<unsigned>(DestAlign.getQuantity()) 2841 << TRange << Op->getSourceRange(); 2842} 2843 2844