SemaChecking.cpp revision 5baba9d98364a3525d6afa15a04cdad82fd6dd30
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/Sema/ScopeInfo.h" 17#include "clang/Analysis/Analyses/FormatString.h" 18#include "clang/AST/ASTContext.h" 19#include "clang/AST/CharUnits.h" 20#include "clang/AST/DeclCXX.h" 21#include "clang/AST/DeclObjC.h" 22#include "clang/AST/ExprCXX.h" 23#include "clang/AST/ExprObjC.h" 24#include "clang/AST/DeclObjC.h" 25#include "clang/AST/StmtCXX.h" 26#include "clang/AST/StmtObjC.h" 27#include "clang/Lex/LiteralSupport.h" 28#include "clang/Lex/Preprocessor.h" 29#include "llvm/ADT/BitVector.h" 30#include "llvm/ADT/STLExtras.h" 31#include "llvm/Support/raw_ostream.h" 32#include "clang/Basic/TargetBuiltins.h" 33#include "clang/Basic/TargetInfo.h" 34#include <limits> 35using namespace clang; 36using namespace sema; 37 38/// getLocationOfStringLiteralByte - Return a source location that points to the 39/// specified byte of the specified string literal. 40/// 41/// Strings are amazingly complex. They can be formed from multiple tokens and 42/// can have escape sequences in them in addition to the usual trigraph and 43/// escaped newline business. This routine handles this complexity. 44/// 45SourceLocation Sema::getLocationOfStringLiteralByte(const StringLiteral *SL, 46 unsigned ByteNo) const { 47 assert(!SL->isWide() && "This doesn't work for wide strings yet"); 48 49 // Loop over all of the tokens in this string until we find the one that 50 // contains the byte we're looking for. 51 unsigned TokNo = 0; 52 while (1) { 53 assert(TokNo < SL->getNumConcatenated() && "Invalid byte number!"); 54 SourceLocation StrTokLoc = SL->getStrTokenLoc(TokNo); 55 56 // Get the spelling of the string so that we can get the data that makes up 57 // the string literal, not the identifier for the macro it is potentially 58 // expanded through. 59 SourceLocation StrTokSpellingLoc = SourceMgr.getSpellingLoc(StrTokLoc); 60 61 // Re-lex the token to get its length and original spelling. 62 std::pair<FileID, unsigned> LocInfo = 63 SourceMgr.getDecomposedLoc(StrTokSpellingLoc); 64 bool Invalid = false; 65 llvm::StringRef Buffer = SourceMgr.getBufferData(LocInfo.first, &Invalid); 66 if (Invalid) 67 return StrTokSpellingLoc; 68 69 const char *StrData = Buffer.data()+LocInfo.second; 70 71 // Create a langops struct and enable trigraphs. This is sufficient for 72 // relexing tokens. 73 LangOptions LangOpts; 74 LangOpts.Trigraphs = true; 75 76 // Create a lexer starting at the beginning of this token. 77 Lexer TheLexer(StrTokSpellingLoc, LangOpts, Buffer.begin(), StrData, 78 Buffer.end()); 79 Token TheTok; 80 TheLexer.LexFromRawLexer(TheTok); 81 82 // Use the StringLiteralParser to compute the length of the string in bytes. 83 StringLiteralParser SLP(&TheTok, 1, PP, /*Complain=*/false); 84 unsigned TokNumBytes = SLP.GetStringLength(); 85 86 // If the byte is in this token, return the location of the byte. 87 if (ByteNo < TokNumBytes || 88 (ByteNo == TokNumBytes && TokNo == SL->getNumConcatenated())) { 89 unsigned Offset = 90 StringLiteralParser::getOffsetOfStringByte(TheTok, ByteNo, PP, 91 /*Complain=*/false); 92 93 // Now that we know the offset of the token in the spelling, use the 94 // preprocessor to get the offset in the original source. 95 return PP.AdvanceToTokenCharacter(StrTokLoc, Offset); 96 } 97 98 // Move to the next string token. 99 ++TokNo; 100 ByteNo -= TokNumBytes; 101 } 102} 103 104/// CheckablePrintfAttr - does a function call have a "printf" attribute 105/// and arguments that merit checking? 106bool Sema::CheckablePrintfAttr(const FormatAttr *Format, CallExpr *TheCall) { 107 if (Format->getType() == "printf") return true; 108 if (Format->getType() == "printf0") { 109 // printf0 allows null "format" string; if so don't check format/args 110 unsigned format_idx = Format->getFormatIdx() - 1; 111 // Does the index refer to the implicit object argument? 112 if (isa<CXXMemberCallExpr>(TheCall)) { 113 if (format_idx == 0) 114 return false; 115 --format_idx; 116 } 117 if (format_idx < TheCall->getNumArgs()) { 118 Expr *Format = TheCall->getArg(format_idx)->IgnoreParenCasts(); 119 if (!Format->isNullPointerConstant(Context, 120 Expr::NPC_ValueDependentIsNull)) 121 return true; 122 } 123 } 124 return false; 125} 126 127ExprResult 128Sema::CheckBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) { 129 ExprResult TheCallResult(Owned(TheCall)); 130 131 switch (BuiltinID) { 132 case Builtin::BI__builtin___CFStringMakeConstantString: 133 assert(TheCall->getNumArgs() == 1 && 134 "Wrong # arguments to builtin CFStringMakeConstantString"); 135 if (CheckObjCString(TheCall->getArg(0))) 136 return ExprError(); 137 break; 138 case Builtin::BI__builtin_stdarg_start: 139 case Builtin::BI__builtin_va_start: 140 if (SemaBuiltinVAStart(TheCall)) 141 return ExprError(); 142 break; 143 case Builtin::BI__builtin_isgreater: 144 case Builtin::BI__builtin_isgreaterequal: 145 case Builtin::BI__builtin_isless: 146 case Builtin::BI__builtin_islessequal: 147 case Builtin::BI__builtin_islessgreater: 148 case Builtin::BI__builtin_isunordered: 149 if (SemaBuiltinUnorderedCompare(TheCall)) 150 return ExprError(); 151 break; 152 case Builtin::BI__builtin_fpclassify: 153 if (SemaBuiltinFPClassification(TheCall, 6)) 154 return ExprError(); 155 break; 156 case Builtin::BI__builtin_isfinite: 157 case Builtin::BI__builtin_isinf: 158 case Builtin::BI__builtin_isinf_sign: 159 case Builtin::BI__builtin_isnan: 160 case Builtin::BI__builtin_isnormal: 161 if (SemaBuiltinFPClassification(TheCall, 1)) 162 return ExprError(); 163 break; 164 case Builtin::BI__builtin_return_address: 165 case Builtin::BI__builtin_frame_address: { 166 llvm::APSInt Result; 167 if (SemaBuiltinConstantArg(TheCall, 0, Result)) 168 return ExprError(); 169 break; 170 } 171 case Builtin::BI__builtin_eh_return_data_regno: { 172 llvm::APSInt Result; 173 if (SemaBuiltinConstantArg(TheCall, 0, Result)) 174 return ExprError(); 175 break; 176 } 177 case Builtin::BI__builtin_shufflevector: 178 return SemaBuiltinShuffleVector(TheCall); 179 // TheCall will be freed by the smart pointer here, but that's fine, since 180 // SemaBuiltinShuffleVector guts it, but then doesn't release it. 181 case Builtin::BI__builtin_prefetch: 182 if (SemaBuiltinPrefetch(TheCall)) 183 return ExprError(); 184 break; 185 case Builtin::BI__builtin_object_size: 186 if (SemaBuiltinObjectSize(TheCall)) 187 return ExprError(); 188 break; 189 case Builtin::BI__builtin_longjmp: 190 if (SemaBuiltinLongjmp(TheCall)) 191 return ExprError(); 192 break; 193 case Builtin::BI__sync_fetch_and_add: 194 case Builtin::BI__sync_fetch_and_sub: 195 case Builtin::BI__sync_fetch_and_or: 196 case Builtin::BI__sync_fetch_and_and: 197 case Builtin::BI__sync_fetch_and_xor: 198 case Builtin::BI__sync_add_and_fetch: 199 case Builtin::BI__sync_sub_and_fetch: 200 case Builtin::BI__sync_and_and_fetch: 201 case Builtin::BI__sync_or_and_fetch: 202 case Builtin::BI__sync_xor_and_fetch: 203 case Builtin::BI__sync_val_compare_and_swap: 204 case Builtin::BI__sync_bool_compare_and_swap: 205 case Builtin::BI__sync_lock_test_and_set: 206 case Builtin::BI__sync_lock_release: 207 return SemaBuiltinAtomicOverloaded(move(TheCallResult)); 208 } 209 210 // Since the target specific builtins for each arch overlap, only check those 211 // of the arch we are compiling for. 212 if (BuiltinID >= Builtin::FirstTSBuiltin) { 213 switch (Context.Target.getTriple().getArch()) { 214 case llvm::Triple::arm: 215 case llvm::Triple::thumb: 216 if (CheckARMBuiltinFunctionCall(BuiltinID, TheCall)) 217 return ExprError(); 218 break; 219 case llvm::Triple::x86: 220 case llvm::Triple::x86_64: 221 if (CheckX86BuiltinFunctionCall(BuiltinID, TheCall)) 222 return ExprError(); 223 break; 224 default: 225 break; 226 } 227 } 228 229 return move(TheCallResult); 230} 231 232bool Sema::CheckX86BuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) { 233 switch (BuiltinID) { 234 case X86::BI__builtin_ia32_palignr128: 235 case X86::BI__builtin_ia32_palignr: { 236 llvm::APSInt Result; 237 if (SemaBuiltinConstantArg(TheCall, 2, Result)) 238 return true; 239 break; 240 } 241 } 242 return false; 243} 244 245// Get the valid immediate range for the specified NEON type code. 246static unsigned RFT(unsigned t, bool shift = false) { 247 bool quad = t & 0x10; 248 249 switch (t & 0x7) { 250 case 0: // i8 251 return shift ? 7 : (8 << (int)quad) - 1; 252 case 1: // i16 253 return shift ? 15 : (4 << (int)quad) - 1; 254 case 2: // i32 255 return shift ? 31 : (2 << (int)quad) - 1; 256 case 3: // i64 257 return shift ? 63 : (1 << (int)quad) - 1; 258 case 4: // f32 259 assert(!shift && "cannot shift float types!"); 260 return (2 << (int)quad) - 1; 261 case 5: // poly8 262 assert(!shift && "cannot shift polynomial types!"); 263 return (8 << (int)quad) - 1; 264 case 6: // poly16 265 assert(!shift && "cannot shift polynomial types!"); 266 return (4 << (int)quad) - 1; 267 case 7: // float16 268 assert(!shift && "cannot shift float types!"); 269 return (4 << (int)quad) - 1; 270 } 271 return 0; 272} 273 274bool Sema::CheckARMBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) { 275 llvm::APSInt Result; 276 277 unsigned mask = 0; 278 unsigned TV = 0; 279 switch (BuiltinID) { 280#define GET_NEON_OVERLOAD_CHECK 281#include "clang/Basic/arm_neon.inc" 282#undef GET_NEON_OVERLOAD_CHECK 283 } 284 285 // For NEON intrinsics which are overloaded on vector element type, validate 286 // the immediate which specifies which variant to emit. 287 if (mask) { 288 unsigned ArgNo = TheCall->getNumArgs()-1; 289 if (SemaBuiltinConstantArg(TheCall, ArgNo, Result)) 290 return true; 291 292 TV = Result.getLimitedValue(32); 293 if ((TV > 31) || (mask & (1 << TV)) == 0) 294 return Diag(TheCall->getLocStart(), diag::err_invalid_neon_type_code) 295 << TheCall->getArg(ArgNo)->getSourceRange(); 296 } 297 298 // For NEON intrinsics which take an immediate value as part of the 299 // instruction, range check them here. 300 unsigned i = 0, l = 0, u = 0; 301 switch (BuiltinID) { 302 default: return false; 303 case ARM::BI__builtin_arm_ssat: i = 1; l = 1; u = 31; break; 304 case ARM::BI__builtin_arm_usat: i = 1; u = 31; break; 305 case ARM::BI__builtin_arm_vcvtr_f: 306 case ARM::BI__builtin_arm_vcvtr_d: i = 1; u = 1; break; 307#define GET_NEON_IMMEDIATE_CHECK 308#include "clang/Basic/arm_neon.inc" 309#undef GET_NEON_IMMEDIATE_CHECK 310 }; 311 312 // Check that the immediate argument is actually a constant. 313 if (SemaBuiltinConstantArg(TheCall, i, Result)) 314 return true; 315 316 // Range check against the upper/lower values for this isntruction. 317 unsigned Val = Result.getZExtValue(); 318 if (Val < l || Val > (u + l)) 319 return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range) 320 << l << u+l << TheCall->getArg(i)->getSourceRange(); 321 322 // FIXME: VFP Intrinsics should error if VFP not present. 323 return false; 324} 325 326/// CheckFunctionCall - Check a direct function call for various correctness 327/// and safety properties not strictly enforced by the C type system. 328bool Sema::CheckFunctionCall(FunctionDecl *FDecl, CallExpr *TheCall) { 329 // Get the IdentifierInfo* for the called function. 330 IdentifierInfo *FnInfo = FDecl->getIdentifier(); 331 332 // None of the checks below are needed for functions that don't have 333 // simple names (e.g., C++ conversion functions). 334 if (!FnInfo) 335 return false; 336 337 // FIXME: This mechanism should be abstracted to be less fragile and 338 // more efficient. For example, just map function ids to custom 339 // handlers. 340 341 // Printf checking. 342 if (const FormatAttr *Format = FDecl->getAttr<FormatAttr>()) { 343 const bool b = Format->getType() == "scanf"; 344 if (b || CheckablePrintfAttr(Format, TheCall)) { 345 bool HasVAListArg = Format->getFirstArg() == 0; 346 CheckPrintfScanfArguments(TheCall, HasVAListArg, 347 Format->getFormatIdx() - 1, 348 HasVAListArg ? 0 : Format->getFirstArg() - 1, 349 !b); 350 } 351 } 352 353 specific_attr_iterator<NonNullAttr> 354 i = FDecl->specific_attr_begin<NonNullAttr>(), 355 e = FDecl->specific_attr_end<NonNullAttr>(); 356 357 for (; i != e; ++i) 358 CheckNonNullArguments(*i, TheCall); 359 360 return false; 361} 362 363bool Sema::CheckBlockCall(NamedDecl *NDecl, CallExpr *TheCall) { 364 // Printf checking. 365 const FormatAttr *Format = NDecl->getAttr<FormatAttr>(); 366 if (!Format) 367 return false; 368 369 const VarDecl *V = dyn_cast<VarDecl>(NDecl); 370 if (!V) 371 return false; 372 373 QualType Ty = V->getType(); 374 if (!Ty->isBlockPointerType()) 375 return false; 376 377 const bool b = Format->getType() == "scanf"; 378 if (!b && !CheckablePrintfAttr(Format, TheCall)) 379 return false; 380 381 bool HasVAListArg = Format->getFirstArg() == 0; 382 CheckPrintfScanfArguments(TheCall, HasVAListArg, Format->getFormatIdx() - 1, 383 HasVAListArg ? 0 : Format->getFirstArg() - 1, !b); 384 385 return false; 386} 387 388/// SemaBuiltinAtomicOverloaded - We have a call to a function like 389/// __sync_fetch_and_add, which is an overloaded function based on the pointer 390/// type of its first argument. The main ActOnCallExpr routines have already 391/// promoted the types of arguments because all of these calls are prototyped as 392/// void(...). 393/// 394/// This function goes through and does final semantic checking for these 395/// builtins, 396ExprResult 397Sema::SemaBuiltinAtomicOverloaded(ExprResult TheCallResult) { 398 CallExpr *TheCall = (CallExpr *)TheCallResult.get(); 399 DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts()); 400 FunctionDecl *FDecl = cast<FunctionDecl>(DRE->getDecl()); 401 402 // Ensure that we have at least one argument to do type inference from. 403 if (TheCall->getNumArgs() < 1) { 404 Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args_at_least) 405 << 0 << 1 << TheCall->getNumArgs() 406 << TheCall->getCallee()->getSourceRange(); 407 return ExprError(); 408 } 409 410 // Inspect the first argument of the atomic builtin. This should always be 411 // a pointer type, whose element is an integral scalar or pointer type. 412 // Because it is a pointer type, we don't have to worry about any implicit 413 // casts here. 414 // FIXME: We don't allow floating point scalars as input. 415 Expr *FirstArg = TheCall->getArg(0); 416 if (!FirstArg->getType()->isPointerType()) { 417 Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer) 418 << FirstArg->getType() << FirstArg->getSourceRange(); 419 return ExprError(); 420 } 421 422 QualType ValType = 423 FirstArg->getType()->getAs<PointerType>()->getPointeeType(); 424 if (!ValType->isIntegerType() && !ValType->isPointerType() && 425 !ValType->isBlockPointerType()) { 426 Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer_intptr) 427 << FirstArg->getType() << FirstArg->getSourceRange(); 428 return ExprError(); 429 } 430 431 // The majority of builtins return a value, but a few have special return 432 // types, so allow them to override appropriately below. 433 QualType ResultType = ValType; 434 435 // We need to figure out which concrete builtin this maps onto. For example, 436 // __sync_fetch_and_add with a 2 byte object turns into 437 // __sync_fetch_and_add_2. 438#define BUILTIN_ROW(x) \ 439 { Builtin::BI##x##_1, Builtin::BI##x##_2, Builtin::BI##x##_4, \ 440 Builtin::BI##x##_8, Builtin::BI##x##_16 } 441 442 static const unsigned BuiltinIndices[][5] = { 443 BUILTIN_ROW(__sync_fetch_and_add), 444 BUILTIN_ROW(__sync_fetch_and_sub), 445 BUILTIN_ROW(__sync_fetch_and_or), 446 BUILTIN_ROW(__sync_fetch_and_and), 447 BUILTIN_ROW(__sync_fetch_and_xor), 448 449 BUILTIN_ROW(__sync_add_and_fetch), 450 BUILTIN_ROW(__sync_sub_and_fetch), 451 BUILTIN_ROW(__sync_and_and_fetch), 452 BUILTIN_ROW(__sync_or_and_fetch), 453 BUILTIN_ROW(__sync_xor_and_fetch), 454 455 BUILTIN_ROW(__sync_val_compare_and_swap), 456 BUILTIN_ROW(__sync_bool_compare_and_swap), 457 BUILTIN_ROW(__sync_lock_test_and_set), 458 BUILTIN_ROW(__sync_lock_release) 459 }; 460#undef BUILTIN_ROW 461 462 // Determine the index of the size. 463 unsigned SizeIndex; 464 switch (Context.getTypeSizeInChars(ValType).getQuantity()) { 465 case 1: SizeIndex = 0; break; 466 case 2: SizeIndex = 1; break; 467 case 4: SizeIndex = 2; break; 468 case 8: SizeIndex = 3; break; 469 case 16: SizeIndex = 4; break; 470 default: 471 Diag(DRE->getLocStart(), diag::err_atomic_builtin_pointer_size) 472 << FirstArg->getType() << FirstArg->getSourceRange(); 473 return ExprError(); 474 } 475 476 // Each of these builtins has one pointer argument, followed by some number of 477 // values (0, 1 or 2) followed by a potentially empty varags list of stuff 478 // that we ignore. Find out which row of BuiltinIndices to read from as well 479 // as the number of fixed args. 480 unsigned BuiltinID = FDecl->getBuiltinID(); 481 unsigned BuiltinIndex, NumFixed = 1; 482 switch (BuiltinID) { 483 default: assert(0 && "Unknown overloaded atomic builtin!"); 484 case Builtin::BI__sync_fetch_and_add: BuiltinIndex = 0; break; 485 case Builtin::BI__sync_fetch_and_sub: BuiltinIndex = 1; break; 486 case Builtin::BI__sync_fetch_and_or: BuiltinIndex = 2; break; 487 case Builtin::BI__sync_fetch_and_and: BuiltinIndex = 3; break; 488 case Builtin::BI__sync_fetch_and_xor: BuiltinIndex = 4; break; 489 490 case Builtin::BI__sync_add_and_fetch: BuiltinIndex = 5; break; 491 case Builtin::BI__sync_sub_and_fetch: BuiltinIndex = 6; break; 492 case Builtin::BI__sync_and_and_fetch: BuiltinIndex = 7; break; 493 case Builtin::BI__sync_or_and_fetch: BuiltinIndex = 8; break; 494 case Builtin::BI__sync_xor_and_fetch: BuiltinIndex = 9; break; 495 496 case Builtin::BI__sync_val_compare_and_swap: 497 BuiltinIndex = 10; 498 NumFixed = 2; 499 break; 500 case Builtin::BI__sync_bool_compare_and_swap: 501 BuiltinIndex = 11; 502 NumFixed = 2; 503 ResultType = Context.BoolTy; 504 break; 505 case Builtin::BI__sync_lock_test_and_set: BuiltinIndex = 12; break; 506 case Builtin::BI__sync_lock_release: 507 BuiltinIndex = 13; 508 NumFixed = 0; 509 ResultType = Context.VoidTy; 510 break; 511 } 512 513 // Now that we know how many fixed arguments we expect, first check that we 514 // have at least that many. 515 if (TheCall->getNumArgs() < 1+NumFixed) { 516 Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args_at_least) 517 << 0 << 1+NumFixed << TheCall->getNumArgs() 518 << TheCall->getCallee()->getSourceRange(); 519 return ExprError(); 520 } 521 522 // Get the decl for the concrete builtin from this, we can tell what the 523 // concrete integer type we should convert to is. 524 unsigned NewBuiltinID = BuiltinIndices[BuiltinIndex][SizeIndex]; 525 const char *NewBuiltinName = Context.BuiltinInfo.GetName(NewBuiltinID); 526 IdentifierInfo *NewBuiltinII = PP.getIdentifierInfo(NewBuiltinName); 527 FunctionDecl *NewBuiltinDecl = 528 cast<FunctionDecl>(LazilyCreateBuiltin(NewBuiltinII, NewBuiltinID, 529 TUScope, false, DRE->getLocStart())); 530 531 // The first argument --- the pointer --- has a fixed type; we 532 // deduce the types of the rest of the arguments accordingly. Walk 533 // the remaining arguments, converting them to the deduced value type. 534 for (unsigned i = 0; i != NumFixed; ++i) { 535 Expr *Arg = TheCall->getArg(i+1); 536 537 // If the argument is an implicit cast, then there was a promotion due to 538 // "...", just remove it now. 539 if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(Arg)) { 540 Arg = ICE->getSubExpr(); 541 ICE->setSubExpr(0); 542 TheCall->setArg(i+1, Arg); 543 } 544 545 // GCC does an implicit conversion to the pointer or integer ValType. This 546 // can fail in some cases (1i -> int**), check for this error case now. 547 CastExpr::CastKind Kind = CastExpr::CK_Unknown; 548 CXXCastPath BasePath; 549 if (CheckCastTypes(Arg->getSourceRange(), ValType, Arg, Kind, BasePath)) 550 return ExprError(); 551 552 // Okay, we have something that *can* be converted to the right type. Check 553 // to see if there is a potentially weird extension going on here. This can 554 // happen when you do an atomic operation on something like an char* and 555 // pass in 42. The 42 gets converted to char. This is even more strange 556 // for things like 45.123 -> char, etc. 557 // FIXME: Do this check. 558 ImpCastExprToType(Arg, ValType, Kind, VK_RValue, &BasePath); 559 TheCall->setArg(i+1, Arg); 560 } 561 562 // Switch the DeclRefExpr to refer to the new decl. 563 DRE->setDecl(NewBuiltinDecl); 564 DRE->setType(NewBuiltinDecl->getType()); 565 566 // Set the callee in the CallExpr. 567 // FIXME: This leaks the original parens and implicit casts. 568 Expr *PromotedCall = DRE; 569 UsualUnaryConversions(PromotedCall); 570 TheCall->setCallee(PromotedCall); 571 572 // Change the result type of the call to match the original value type. This 573 // is arbitrary, but the codegen for these builtins ins design to handle it 574 // gracefully. 575 TheCall->setType(ResultType); 576 577 return move(TheCallResult); 578} 579 580 581/// CheckObjCString - Checks that the argument to the builtin 582/// CFString constructor is correct 583/// FIXME: GCC currently emits the following warning: 584/// "warning: input conversion stopped due to an input byte that does not 585/// belong to the input codeset UTF-8" 586/// Note: It might also make sense to do the UTF-16 conversion here (would 587/// simplify the backend). 588bool Sema::CheckObjCString(Expr *Arg) { 589 Arg = Arg->IgnoreParenCasts(); 590 StringLiteral *Literal = dyn_cast<StringLiteral>(Arg); 591 592 if (!Literal || Literal->isWide()) { 593 Diag(Arg->getLocStart(), diag::err_cfstring_literal_not_string_constant) 594 << Arg->getSourceRange(); 595 return true; 596 } 597 598 size_t NulPos = Literal->getString().find('\0'); 599 if (NulPos != llvm::StringRef::npos) { 600 Diag(getLocationOfStringLiteralByte(Literal, NulPos), 601 diag::warn_cfstring_literal_contains_nul_character) 602 << Arg->getSourceRange(); 603 } 604 605 return false; 606} 607 608/// SemaBuiltinVAStart - Check the arguments to __builtin_va_start for validity. 609/// Emit an error and return true on failure, return false on success. 610bool Sema::SemaBuiltinVAStart(CallExpr *TheCall) { 611 Expr *Fn = TheCall->getCallee(); 612 if (TheCall->getNumArgs() > 2) { 613 Diag(TheCall->getArg(2)->getLocStart(), 614 diag::err_typecheck_call_too_many_args) 615 << 0 /*function call*/ << 2 << TheCall->getNumArgs() 616 << Fn->getSourceRange() 617 << SourceRange(TheCall->getArg(2)->getLocStart(), 618 (*(TheCall->arg_end()-1))->getLocEnd()); 619 return true; 620 } 621 622 if (TheCall->getNumArgs() < 2) { 623 return Diag(TheCall->getLocEnd(), 624 diag::err_typecheck_call_too_few_args_at_least) 625 << 0 /*function call*/ << 2 << TheCall->getNumArgs(); 626 } 627 628 // Determine whether the current function is variadic or not. 629 BlockScopeInfo *CurBlock = getCurBlock(); 630 bool isVariadic; 631 if (CurBlock) 632 isVariadic = CurBlock->TheDecl->isVariadic(); 633 else if (FunctionDecl *FD = getCurFunctionDecl()) 634 isVariadic = FD->isVariadic(); 635 else 636 isVariadic = getCurMethodDecl()->isVariadic(); 637 638 if (!isVariadic) { 639 Diag(Fn->getLocStart(), diag::err_va_start_used_in_non_variadic_function); 640 return true; 641 } 642 643 // Verify that the second argument to the builtin is the last argument of the 644 // current function or method. 645 bool SecondArgIsLastNamedArgument = false; 646 const Expr *Arg = TheCall->getArg(1)->IgnoreParenCasts(); 647 648 if (const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(Arg)) { 649 if (const ParmVarDecl *PV = dyn_cast<ParmVarDecl>(DR->getDecl())) { 650 // FIXME: This isn't correct for methods (results in bogus warning). 651 // Get the last formal in the current function. 652 const ParmVarDecl *LastArg; 653 if (CurBlock) 654 LastArg = *(CurBlock->TheDecl->param_end()-1); 655 else if (FunctionDecl *FD = getCurFunctionDecl()) 656 LastArg = *(FD->param_end()-1); 657 else 658 LastArg = *(getCurMethodDecl()->param_end()-1); 659 SecondArgIsLastNamedArgument = PV == LastArg; 660 } 661 } 662 663 if (!SecondArgIsLastNamedArgument) 664 Diag(TheCall->getArg(1)->getLocStart(), 665 diag::warn_second_parameter_of_va_start_not_last_named_argument); 666 return false; 667} 668 669/// SemaBuiltinUnorderedCompare - Handle functions like __builtin_isgreater and 670/// friends. This is declared to take (...), so we have to check everything. 671bool Sema::SemaBuiltinUnorderedCompare(CallExpr *TheCall) { 672 if (TheCall->getNumArgs() < 2) 673 return Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args) 674 << 0 << 2 << TheCall->getNumArgs()/*function call*/; 675 if (TheCall->getNumArgs() > 2) 676 return Diag(TheCall->getArg(2)->getLocStart(), 677 diag::err_typecheck_call_too_many_args) 678 << 0 /*function call*/ << 2 << TheCall->getNumArgs() 679 << SourceRange(TheCall->getArg(2)->getLocStart(), 680 (*(TheCall->arg_end()-1))->getLocEnd()); 681 682 Expr *OrigArg0 = TheCall->getArg(0); 683 Expr *OrigArg1 = TheCall->getArg(1); 684 685 // Do standard promotions between the two arguments, returning their common 686 // type. 687 QualType Res = UsualArithmeticConversions(OrigArg0, OrigArg1, false); 688 689 // Make sure any conversions are pushed back into the call; this is 690 // type safe since unordered compare builtins are declared as "_Bool 691 // foo(...)". 692 TheCall->setArg(0, OrigArg0); 693 TheCall->setArg(1, OrigArg1); 694 695 if (OrigArg0->isTypeDependent() || OrigArg1->isTypeDependent()) 696 return false; 697 698 // If the common type isn't a real floating type, then the arguments were 699 // invalid for this operation. 700 if (!Res->isRealFloatingType()) 701 return Diag(OrigArg0->getLocStart(), 702 diag::err_typecheck_call_invalid_ordered_compare) 703 << OrigArg0->getType() << OrigArg1->getType() 704 << SourceRange(OrigArg0->getLocStart(), OrigArg1->getLocEnd()); 705 706 return false; 707} 708 709/// SemaBuiltinSemaBuiltinFPClassification - Handle functions like 710/// __builtin_isnan and friends. This is declared to take (...), so we have 711/// to check everything. We expect the last argument to be a floating point 712/// value. 713bool Sema::SemaBuiltinFPClassification(CallExpr *TheCall, unsigned NumArgs) { 714 if (TheCall->getNumArgs() < NumArgs) 715 return Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args) 716 << 0 << NumArgs << TheCall->getNumArgs()/*function call*/; 717 if (TheCall->getNumArgs() > NumArgs) 718 return Diag(TheCall->getArg(NumArgs)->getLocStart(), 719 diag::err_typecheck_call_too_many_args) 720 << 0 /*function call*/ << NumArgs << TheCall->getNumArgs() 721 << SourceRange(TheCall->getArg(NumArgs)->getLocStart(), 722 (*(TheCall->arg_end()-1))->getLocEnd()); 723 724 Expr *OrigArg = TheCall->getArg(NumArgs-1); 725 726 if (OrigArg->isTypeDependent()) 727 return false; 728 729 // This operation requires a non-_Complex floating-point number. 730 if (!OrigArg->getType()->isRealFloatingType()) 731 return Diag(OrigArg->getLocStart(), 732 diag::err_typecheck_call_invalid_unary_fp) 733 << OrigArg->getType() << OrigArg->getSourceRange(); 734 735 // If this is an implicit conversion from float -> double, remove it. 736 if (ImplicitCastExpr *Cast = dyn_cast<ImplicitCastExpr>(OrigArg)) { 737 Expr *CastArg = Cast->getSubExpr(); 738 if (CastArg->getType()->isSpecificBuiltinType(BuiltinType::Float)) { 739 assert(Cast->getType()->isSpecificBuiltinType(BuiltinType::Double) && 740 "promotion from float to double is the only expected cast here"); 741 Cast->setSubExpr(0); 742 TheCall->setArg(NumArgs-1, CastArg); 743 OrigArg = CastArg; 744 } 745 } 746 747 return false; 748} 749 750/// SemaBuiltinShuffleVector - Handle __builtin_shufflevector. 751// This is declared to take (...), so we have to check everything. 752ExprResult Sema::SemaBuiltinShuffleVector(CallExpr *TheCall) { 753 if (TheCall->getNumArgs() < 2) 754 return ExprError(Diag(TheCall->getLocEnd(), 755 diag::err_typecheck_call_too_few_args_at_least) 756 << 0 /*function call*/ << 2 << TheCall->getNumArgs() 757 << TheCall->getSourceRange()); 758 759 // Determine which of the following types of shufflevector we're checking: 760 // 1) unary, vector mask: (lhs, mask) 761 // 2) binary, vector mask: (lhs, rhs, mask) 762 // 3) binary, scalar mask: (lhs, rhs, index, ..., index) 763 QualType resType = TheCall->getArg(0)->getType(); 764 unsigned numElements = 0; 765 766 if (!TheCall->getArg(0)->isTypeDependent() && 767 !TheCall->getArg(1)->isTypeDependent()) { 768 QualType LHSType = TheCall->getArg(0)->getType(); 769 QualType RHSType = TheCall->getArg(1)->getType(); 770 771 if (!LHSType->isVectorType() || !RHSType->isVectorType()) { 772 Diag(TheCall->getLocStart(), diag::err_shufflevector_non_vector) 773 << SourceRange(TheCall->getArg(0)->getLocStart(), 774 TheCall->getArg(1)->getLocEnd()); 775 return ExprError(); 776 } 777 778 numElements = LHSType->getAs<VectorType>()->getNumElements(); 779 unsigned numResElements = TheCall->getNumArgs() - 2; 780 781 // Check to see if we have a call with 2 vector arguments, the unary shuffle 782 // with mask. If so, verify that RHS is an integer vector type with the 783 // same number of elts as lhs. 784 if (TheCall->getNumArgs() == 2) { 785 if (!RHSType->hasIntegerRepresentation() || 786 RHSType->getAs<VectorType>()->getNumElements() != numElements) 787 Diag(TheCall->getLocStart(), diag::err_shufflevector_incompatible_vector) 788 << SourceRange(TheCall->getArg(1)->getLocStart(), 789 TheCall->getArg(1)->getLocEnd()); 790 numResElements = numElements; 791 } 792 else if (!Context.hasSameUnqualifiedType(LHSType, RHSType)) { 793 Diag(TheCall->getLocStart(), diag::err_shufflevector_incompatible_vector) 794 << SourceRange(TheCall->getArg(0)->getLocStart(), 795 TheCall->getArg(1)->getLocEnd()); 796 return ExprError(); 797 } else if (numElements != numResElements) { 798 QualType eltType = LHSType->getAs<VectorType>()->getElementType(); 799 resType = Context.getVectorType(eltType, numResElements, 800 VectorType::NotAltiVec); 801 } 802 } 803 804 for (unsigned i = 2; i < TheCall->getNumArgs(); i++) { 805 if (TheCall->getArg(i)->isTypeDependent() || 806 TheCall->getArg(i)->isValueDependent()) 807 continue; 808 809 llvm::APSInt Result(32); 810 if (!TheCall->getArg(i)->isIntegerConstantExpr(Result, Context)) 811 return ExprError(Diag(TheCall->getLocStart(), 812 diag::err_shufflevector_nonconstant_argument) 813 << TheCall->getArg(i)->getSourceRange()); 814 815 if (Result.getActiveBits() > 64 || Result.getZExtValue() >= numElements*2) 816 return ExprError(Diag(TheCall->getLocStart(), 817 diag::err_shufflevector_argument_too_large) 818 << TheCall->getArg(i)->getSourceRange()); 819 } 820 821 llvm::SmallVector<Expr*, 32> exprs; 822 823 for (unsigned i = 0, e = TheCall->getNumArgs(); i != e; i++) { 824 exprs.push_back(TheCall->getArg(i)); 825 TheCall->setArg(i, 0); 826 } 827 828 return Owned(new (Context) ShuffleVectorExpr(Context, exprs.begin(), 829 exprs.size(), resType, 830 TheCall->getCallee()->getLocStart(), 831 TheCall->getRParenLoc())); 832} 833 834/// SemaBuiltinPrefetch - Handle __builtin_prefetch. 835// This is declared to take (const void*, ...) and can take two 836// optional constant int args. 837bool Sema::SemaBuiltinPrefetch(CallExpr *TheCall) { 838 unsigned NumArgs = TheCall->getNumArgs(); 839 840 if (NumArgs > 3) 841 return Diag(TheCall->getLocEnd(), 842 diag::err_typecheck_call_too_many_args_at_most) 843 << 0 /*function call*/ << 3 << NumArgs 844 << TheCall->getSourceRange(); 845 846 // Argument 0 is checked for us and the remaining arguments must be 847 // constant integers. 848 for (unsigned i = 1; i != NumArgs; ++i) { 849 Expr *Arg = TheCall->getArg(i); 850 851 llvm::APSInt Result; 852 if (SemaBuiltinConstantArg(TheCall, i, Result)) 853 return true; 854 855 // FIXME: gcc issues a warning and rewrites these to 0. These 856 // seems especially odd for the third argument since the default 857 // is 3. 858 if (i == 1) { 859 if (Result.getLimitedValue() > 1) 860 return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range) 861 << "0" << "1" << Arg->getSourceRange(); 862 } else { 863 if (Result.getLimitedValue() > 3) 864 return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range) 865 << "0" << "3" << Arg->getSourceRange(); 866 } 867 } 868 869 return false; 870} 871 872/// SemaBuiltinConstantArg - Handle a check if argument ArgNum of CallExpr 873/// TheCall is a constant expression. 874bool Sema::SemaBuiltinConstantArg(CallExpr *TheCall, int ArgNum, 875 llvm::APSInt &Result) { 876 Expr *Arg = TheCall->getArg(ArgNum); 877 DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts()); 878 FunctionDecl *FDecl = cast<FunctionDecl>(DRE->getDecl()); 879 880 if (Arg->isTypeDependent() || Arg->isValueDependent()) return false; 881 882 if (!Arg->isIntegerConstantExpr(Result, Context)) 883 return Diag(TheCall->getLocStart(), diag::err_constant_integer_arg_type) 884 << FDecl->getDeclName() << Arg->getSourceRange(); 885 886 return false; 887} 888 889/// SemaBuiltinObjectSize - Handle __builtin_object_size(void *ptr, 890/// int type). This simply type checks that type is one of the defined 891/// constants (0-3). 892// For compatability check 0-3, llvm only handles 0 and 2. 893bool Sema::SemaBuiltinObjectSize(CallExpr *TheCall) { 894 llvm::APSInt Result; 895 896 // Check constant-ness first. 897 if (SemaBuiltinConstantArg(TheCall, 1, Result)) 898 return true; 899 900 Expr *Arg = TheCall->getArg(1); 901 if (Result.getSExtValue() < 0 || Result.getSExtValue() > 3) { 902 return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range) 903 << "0" << "3" << SourceRange(Arg->getLocStart(), Arg->getLocEnd()); 904 } 905 906 return false; 907} 908 909/// SemaBuiltinLongjmp - Handle __builtin_longjmp(void *env[5], int val). 910/// This checks that val is a constant 1. 911bool Sema::SemaBuiltinLongjmp(CallExpr *TheCall) { 912 Expr *Arg = TheCall->getArg(1); 913 llvm::APSInt Result; 914 915 // TODO: This is less than ideal. Overload this to take a value. 916 if (SemaBuiltinConstantArg(TheCall, 1, Result)) 917 return true; 918 919 if (Result != 1) 920 return Diag(TheCall->getLocStart(), diag::err_builtin_longjmp_invalid_val) 921 << SourceRange(Arg->getLocStart(), Arg->getLocEnd()); 922 923 return false; 924} 925 926// Handle i > 1 ? "x" : "y", recursivelly 927bool Sema::SemaCheckStringLiteral(const Expr *E, const CallExpr *TheCall, 928 bool HasVAListArg, 929 unsigned format_idx, unsigned firstDataArg, 930 bool isPrintf) { 931 932 if (E->isTypeDependent() || E->isValueDependent()) 933 return false; 934 935 switch (E->getStmtClass()) { 936 case Stmt::ConditionalOperatorClass: { 937 const ConditionalOperator *C = cast<ConditionalOperator>(E); 938 return SemaCheckStringLiteral(C->getTrueExpr(), TheCall, HasVAListArg, 939 format_idx, firstDataArg, isPrintf) 940 && SemaCheckStringLiteral(C->getRHS(), TheCall, HasVAListArg, 941 format_idx, firstDataArg, isPrintf); 942 } 943 944 case Stmt::ImplicitCastExprClass: { 945 const ImplicitCastExpr *Expr = cast<ImplicitCastExpr>(E); 946 return SemaCheckStringLiteral(Expr->getSubExpr(), TheCall, HasVAListArg, 947 format_idx, firstDataArg, isPrintf); 948 } 949 950 case Stmt::ParenExprClass: { 951 const ParenExpr *Expr = cast<ParenExpr>(E); 952 return SemaCheckStringLiteral(Expr->getSubExpr(), TheCall, HasVAListArg, 953 format_idx, firstDataArg, isPrintf); 954 } 955 956 case Stmt::DeclRefExprClass: { 957 const DeclRefExpr *DR = cast<DeclRefExpr>(E); 958 959 // As an exception, do not flag errors for variables binding to 960 // const string literals. 961 if (const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl())) { 962 bool isConstant = false; 963 QualType T = DR->getType(); 964 965 if (const ArrayType *AT = Context.getAsArrayType(T)) { 966 isConstant = AT->getElementType().isConstant(Context); 967 } else if (const PointerType *PT = T->getAs<PointerType>()) { 968 isConstant = T.isConstant(Context) && 969 PT->getPointeeType().isConstant(Context); 970 } 971 972 if (isConstant) { 973 if (const Expr *Init = VD->getAnyInitializer()) 974 return SemaCheckStringLiteral(Init, TheCall, 975 HasVAListArg, format_idx, firstDataArg, 976 isPrintf); 977 } 978 979 // For vprintf* functions (i.e., HasVAListArg==true), we add a 980 // special check to see if the format string is a function parameter 981 // of the function calling the printf function. If the function 982 // has an attribute indicating it is a printf-like function, then we 983 // should suppress warnings concerning non-literals being used in a call 984 // to a vprintf function. For example: 985 // 986 // void 987 // logmessage(char const *fmt __attribute__ (format (printf, 1, 2)), ...){ 988 // va_list ap; 989 // va_start(ap, fmt); 990 // vprintf(fmt, ap); // Do NOT emit a warning about "fmt". 991 // ... 992 // 993 // 994 // FIXME: We don't have full attribute support yet, so just check to see 995 // if the argument is a DeclRefExpr that references a parameter. We'll 996 // add proper support for checking the attribute later. 997 if (HasVAListArg) 998 if (isa<ParmVarDecl>(VD)) 999 return true; 1000 } 1001 1002 return false; 1003 } 1004 1005 case Stmt::CallExprClass: { 1006 const CallExpr *CE = cast<CallExpr>(E); 1007 if (const ImplicitCastExpr *ICE 1008 = dyn_cast<ImplicitCastExpr>(CE->getCallee())) { 1009 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(ICE->getSubExpr())) { 1010 if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(DRE->getDecl())) { 1011 if (const FormatArgAttr *FA = FD->getAttr<FormatArgAttr>()) { 1012 unsigned ArgIndex = FA->getFormatIdx(); 1013 const Expr *Arg = CE->getArg(ArgIndex - 1); 1014 1015 return SemaCheckStringLiteral(Arg, TheCall, HasVAListArg, 1016 format_idx, firstDataArg, isPrintf); 1017 } 1018 } 1019 } 1020 } 1021 1022 return false; 1023 } 1024 case Stmt::ObjCStringLiteralClass: 1025 case Stmt::StringLiteralClass: { 1026 const StringLiteral *StrE = NULL; 1027 1028 if (const ObjCStringLiteral *ObjCFExpr = dyn_cast<ObjCStringLiteral>(E)) 1029 StrE = ObjCFExpr->getString(); 1030 else 1031 StrE = cast<StringLiteral>(E); 1032 1033 if (StrE) { 1034 CheckFormatString(StrE, E, TheCall, HasVAListArg, format_idx, 1035 firstDataArg, isPrintf); 1036 return true; 1037 } 1038 1039 return false; 1040 } 1041 1042 default: 1043 return false; 1044 } 1045} 1046 1047void 1048Sema::CheckNonNullArguments(const NonNullAttr *NonNull, 1049 const CallExpr *TheCall) { 1050 for (NonNullAttr::args_iterator i = NonNull->args_begin(), 1051 e = NonNull->args_end(); 1052 i != e; ++i) { 1053 const Expr *ArgExpr = TheCall->getArg(*i); 1054 if (ArgExpr->isNullPointerConstant(Context, 1055 Expr::NPC_ValueDependentIsNotNull)) 1056 Diag(TheCall->getCallee()->getLocStart(), diag::warn_null_arg) 1057 << ArgExpr->getSourceRange(); 1058 } 1059} 1060 1061/// CheckPrintfScanfArguments - Check calls to printf and scanf (and similar 1062/// functions) for correct use of format strings. 1063void 1064Sema::CheckPrintfScanfArguments(const CallExpr *TheCall, bool HasVAListArg, 1065 unsigned format_idx, unsigned firstDataArg, 1066 bool isPrintf) { 1067 1068 const Expr *Fn = TheCall->getCallee(); 1069 1070 // The way the format attribute works in GCC, the implicit this argument 1071 // of member functions is counted. However, it doesn't appear in our own 1072 // lists, so decrement format_idx in that case. 1073 if (isa<CXXMemberCallExpr>(TheCall)) { 1074 // Catch a format attribute mistakenly referring to the object argument. 1075 if (format_idx == 0) 1076 return; 1077 --format_idx; 1078 if(firstDataArg != 0) 1079 --firstDataArg; 1080 } 1081 1082 // CHECK: printf/scanf-like function is called with no format string. 1083 if (format_idx >= TheCall->getNumArgs()) { 1084 Diag(TheCall->getRParenLoc(), diag::warn_missing_format_string) 1085 << Fn->getSourceRange(); 1086 return; 1087 } 1088 1089 const Expr *OrigFormatExpr = TheCall->getArg(format_idx)->IgnoreParenCasts(); 1090 1091 // CHECK: format string is not a string literal. 1092 // 1093 // Dynamically generated format strings are difficult to 1094 // automatically vet at compile time. Requiring that format strings 1095 // are string literals: (1) permits the checking of format strings by 1096 // the compiler and thereby (2) can practically remove the source of 1097 // many format string exploits. 1098 1099 // Format string can be either ObjC string (e.g. @"%d") or 1100 // C string (e.g. "%d") 1101 // ObjC string uses the same format specifiers as C string, so we can use 1102 // the same format string checking logic for both ObjC and C strings. 1103 if (SemaCheckStringLiteral(OrigFormatExpr, TheCall, HasVAListArg, format_idx, 1104 firstDataArg, isPrintf)) 1105 return; // Literal format string found, check done! 1106 1107 // If there are no arguments specified, warn with -Wformat-security, otherwise 1108 // warn only with -Wformat-nonliteral. 1109 if (TheCall->getNumArgs() == format_idx+1) 1110 Diag(TheCall->getArg(format_idx)->getLocStart(), 1111 diag::warn_format_nonliteral_noargs) 1112 << OrigFormatExpr->getSourceRange(); 1113 else 1114 Diag(TheCall->getArg(format_idx)->getLocStart(), 1115 diag::warn_format_nonliteral) 1116 << OrigFormatExpr->getSourceRange(); 1117} 1118 1119namespace { 1120class CheckFormatHandler : public analyze_format_string::FormatStringHandler { 1121protected: 1122 Sema &S; 1123 const StringLiteral *FExpr; 1124 const Expr *OrigFormatExpr; 1125 const unsigned FirstDataArg; 1126 const unsigned NumDataArgs; 1127 const bool IsObjCLiteral; 1128 const char *Beg; // Start of format string. 1129 const bool HasVAListArg; 1130 const CallExpr *TheCall; 1131 unsigned FormatIdx; 1132 llvm::BitVector CoveredArgs; 1133 bool usesPositionalArgs; 1134 bool atFirstArg; 1135public: 1136 CheckFormatHandler(Sema &s, const StringLiteral *fexpr, 1137 const Expr *origFormatExpr, unsigned firstDataArg, 1138 unsigned numDataArgs, bool isObjCLiteral, 1139 const char *beg, bool hasVAListArg, 1140 const CallExpr *theCall, unsigned formatIdx) 1141 : S(s), FExpr(fexpr), OrigFormatExpr(origFormatExpr), 1142 FirstDataArg(firstDataArg), 1143 NumDataArgs(numDataArgs), 1144 IsObjCLiteral(isObjCLiteral), Beg(beg), 1145 HasVAListArg(hasVAListArg), 1146 TheCall(theCall), FormatIdx(formatIdx), 1147 usesPositionalArgs(false), atFirstArg(true) { 1148 CoveredArgs.resize(numDataArgs); 1149 CoveredArgs.reset(); 1150 } 1151 1152 void DoneProcessing(); 1153 1154 void HandleIncompleteSpecifier(const char *startSpecifier, 1155 unsigned specifierLen); 1156 1157 virtual void HandleInvalidPosition(const char *startSpecifier, 1158 unsigned specifierLen, 1159 analyze_format_string::PositionContext p); 1160 1161 virtual void HandleZeroPosition(const char *startPos, unsigned posLen); 1162 1163 void HandleNullChar(const char *nullCharacter); 1164 1165protected: 1166 bool HandleInvalidConversionSpecifier(unsigned argIndex, SourceLocation Loc, 1167 const char *startSpec, 1168 unsigned specifierLen, 1169 const char *csStart, unsigned csLen); 1170 1171 SourceRange getFormatStringRange(); 1172 CharSourceRange getSpecifierRange(const char *startSpecifier, 1173 unsigned specifierLen); 1174 SourceLocation getLocationOfByte(const char *x); 1175 1176 const Expr *getDataArg(unsigned i) const; 1177 1178 bool CheckNumArgs(const analyze_format_string::FormatSpecifier &FS, 1179 const analyze_format_string::ConversionSpecifier &CS, 1180 const char *startSpecifier, unsigned specifierLen, 1181 unsigned argIndex); 1182}; 1183} 1184 1185SourceRange CheckFormatHandler::getFormatStringRange() { 1186 return OrigFormatExpr->getSourceRange(); 1187} 1188 1189CharSourceRange CheckFormatHandler:: 1190getSpecifierRange(const char *startSpecifier, unsigned specifierLen) { 1191 SourceLocation Start = getLocationOfByte(startSpecifier); 1192 SourceLocation End = getLocationOfByte(startSpecifier + specifierLen - 1); 1193 1194 // Advance the end SourceLocation by one due to half-open ranges. 1195 End = End.getFileLocWithOffset(1); 1196 1197 return CharSourceRange::getCharRange(Start, End); 1198} 1199 1200SourceLocation CheckFormatHandler::getLocationOfByte(const char *x) { 1201 return S.getLocationOfStringLiteralByte(FExpr, x - Beg); 1202} 1203 1204void CheckFormatHandler::HandleIncompleteSpecifier(const char *startSpecifier, 1205 unsigned specifierLen){ 1206 SourceLocation Loc = getLocationOfByte(startSpecifier); 1207 S.Diag(Loc, diag::warn_printf_incomplete_specifier) 1208 << getSpecifierRange(startSpecifier, specifierLen); 1209} 1210 1211void 1212CheckFormatHandler::HandleInvalidPosition(const char *startPos, unsigned posLen, 1213 analyze_format_string::PositionContext p) { 1214 SourceLocation Loc = getLocationOfByte(startPos); 1215 S.Diag(Loc, diag::warn_format_invalid_positional_specifier) 1216 << (unsigned) p << getSpecifierRange(startPos, posLen); 1217} 1218 1219void CheckFormatHandler::HandleZeroPosition(const char *startPos, 1220 unsigned posLen) { 1221 SourceLocation Loc = getLocationOfByte(startPos); 1222 S.Diag(Loc, diag::warn_format_zero_positional_specifier) 1223 << getSpecifierRange(startPos, posLen); 1224} 1225 1226void CheckFormatHandler::HandleNullChar(const char *nullCharacter) { 1227 // The presence of a null character is likely an error. 1228 S.Diag(getLocationOfByte(nullCharacter), 1229 diag::warn_printf_format_string_contains_null_char) 1230 << getFormatStringRange(); 1231} 1232 1233const Expr *CheckFormatHandler::getDataArg(unsigned i) const { 1234 return TheCall->getArg(FirstDataArg + i); 1235} 1236 1237void CheckFormatHandler::DoneProcessing() { 1238 // Does the number of data arguments exceed the number of 1239 // format conversions in the format string? 1240 if (!HasVAListArg) { 1241 // Find any arguments that weren't covered. 1242 CoveredArgs.flip(); 1243 signed notCoveredArg = CoveredArgs.find_first(); 1244 if (notCoveredArg >= 0) { 1245 assert((unsigned)notCoveredArg < NumDataArgs); 1246 S.Diag(getDataArg((unsigned) notCoveredArg)->getLocStart(), 1247 diag::warn_printf_data_arg_not_used) 1248 << getFormatStringRange(); 1249 } 1250 } 1251} 1252 1253bool 1254CheckFormatHandler::HandleInvalidConversionSpecifier(unsigned argIndex, 1255 SourceLocation Loc, 1256 const char *startSpec, 1257 unsigned specifierLen, 1258 const char *csStart, 1259 unsigned csLen) { 1260 1261 bool keepGoing = true; 1262 if (argIndex < NumDataArgs) { 1263 // Consider the argument coverered, even though the specifier doesn't 1264 // make sense. 1265 CoveredArgs.set(argIndex); 1266 } 1267 else { 1268 // If argIndex exceeds the number of data arguments we 1269 // don't issue a warning because that is just a cascade of warnings (and 1270 // they may have intended '%%' anyway). We don't want to continue processing 1271 // the format string after this point, however, as we will like just get 1272 // gibberish when trying to match arguments. 1273 keepGoing = false; 1274 } 1275 1276 S.Diag(Loc, diag::warn_format_invalid_conversion) 1277 << llvm::StringRef(csStart, csLen) 1278 << getSpecifierRange(startSpec, specifierLen); 1279 1280 return keepGoing; 1281} 1282 1283bool 1284CheckFormatHandler::CheckNumArgs( 1285 const analyze_format_string::FormatSpecifier &FS, 1286 const analyze_format_string::ConversionSpecifier &CS, 1287 const char *startSpecifier, unsigned specifierLen, unsigned argIndex) { 1288 1289 if (argIndex >= NumDataArgs) { 1290 if (FS.usesPositionalArg()) { 1291 S.Diag(getLocationOfByte(CS.getStart()), 1292 diag::warn_printf_positional_arg_exceeds_data_args) 1293 << (argIndex+1) << NumDataArgs 1294 << getSpecifierRange(startSpecifier, specifierLen); 1295 } 1296 else { 1297 S.Diag(getLocationOfByte(CS.getStart()), 1298 diag::warn_printf_insufficient_data_args) 1299 << getSpecifierRange(startSpecifier, specifierLen); 1300 } 1301 1302 return false; 1303 } 1304 return true; 1305} 1306 1307//===--- CHECK: Printf format string checking ------------------------------===// 1308 1309namespace { 1310class CheckPrintfHandler : public CheckFormatHandler { 1311public: 1312 CheckPrintfHandler(Sema &s, const StringLiteral *fexpr, 1313 const Expr *origFormatExpr, unsigned firstDataArg, 1314 unsigned numDataArgs, bool isObjCLiteral, 1315 const char *beg, bool hasVAListArg, 1316 const CallExpr *theCall, unsigned formatIdx) 1317 : CheckFormatHandler(s, fexpr, origFormatExpr, firstDataArg, 1318 numDataArgs, isObjCLiteral, beg, hasVAListArg, 1319 theCall, formatIdx) {} 1320 1321 1322 bool HandleInvalidPrintfConversionSpecifier( 1323 const analyze_printf::PrintfSpecifier &FS, 1324 const char *startSpecifier, 1325 unsigned specifierLen); 1326 1327 bool HandlePrintfSpecifier(const analyze_printf::PrintfSpecifier &FS, 1328 const char *startSpecifier, 1329 unsigned specifierLen); 1330 1331 bool HandleAmount(const analyze_format_string::OptionalAmount &Amt, unsigned k, 1332 const char *startSpecifier, unsigned specifierLen); 1333 void HandleInvalidAmount(const analyze_printf::PrintfSpecifier &FS, 1334 const analyze_printf::OptionalAmount &Amt, 1335 unsigned type, 1336 const char *startSpecifier, unsigned specifierLen); 1337 void HandleFlag(const analyze_printf::PrintfSpecifier &FS, 1338 const analyze_printf::OptionalFlag &flag, 1339 const char *startSpecifier, unsigned specifierLen); 1340 void HandleIgnoredFlag(const analyze_printf::PrintfSpecifier &FS, 1341 const analyze_printf::OptionalFlag &ignoredFlag, 1342 const analyze_printf::OptionalFlag &flag, 1343 const char *startSpecifier, unsigned specifierLen); 1344}; 1345} 1346 1347bool CheckPrintfHandler::HandleInvalidPrintfConversionSpecifier( 1348 const analyze_printf::PrintfSpecifier &FS, 1349 const char *startSpecifier, 1350 unsigned specifierLen) { 1351 const analyze_printf::PrintfConversionSpecifier &CS = 1352 FS.getConversionSpecifier(); 1353 1354 return HandleInvalidConversionSpecifier(FS.getArgIndex(), 1355 getLocationOfByte(CS.getStart()), 1356 startSpecifier, specifierLen, 1357 CS.getStart(), CS.getLength()); 1358} 1359 1360bool CheckPrintfHandler::HandleAmount( 1361 const analyze_format_string::OptionalAmount &Amt, 1362 unsigned k, const char *startSpecifier, 1363 unsigned specifierLen) { 1364 1365 if (Amt.hasDataArgument()) { 1366 if (!HasVAListArg) { 1367 unsigned argIndex = Amt.getArgIndex(); 1368 if (argIndex >= NumDataArgs) { 1369 S.Diag(getLocationOfByte(Amt.getStart()), 1370 diag::warn_printf_asterisk_missing_arg) 1371 << k << getSpecifierRange(startSpecifier, specifierLen); 1372 // Don't do any more checking. We will just emit 1373 // spurious errors. 1374 return false; 1375 } 1376 1377 // Type check the data argument. It should be an 'int'. 1378 // Although not in conformance with C99, we also allow the argument to be 1379 // an 'unsigned int' as that is a reasonably safe case. GCC also 1380 // doesn't emit a warning for that case. 1381 CoveredArgs.set(argIndex); 1382 const Expr *Arg = getDataArg(argIndex); 1383 QualType T = Arg->getType(); 1384 1385 const analyze_printf::ArgTypeResult &ATR = Amt.getArgType(S.Context); 1386 assert(ATR.isValid()); 1387 1388 if (!ATR.matchesType(S.Context, T)) { 1389 S.Diag(getLocationOfByte(Amt.getStart()), 1390 diag::warn_printf_asterisk_wrong_type) 1391 << k 1392 << ATR.getRepresentativeType(S.Context) << T 1393 << getSpecifierRange(startSpecifier, specifierLen) 1394 << Arg->getSourceRange(); 1395 // Don't do any more checking. We will just emit 1396 // spurious errors. 1397 return false; 1398 } 1399 } 1400 } 1401 return true; 1402} 1403 1404void CheckPrintfHandler::HandleInvalidAmount( 1405 const analyze_printf::PrintfSpecifier &FS, 1406 const analyze_printf::OptionalAmount &Amt, 1407 unsigned type, 1408 const char *startSpecifier, 1409 unsigned specifierLen) { 1410 const analyze_printf::PrintfConversionSpecifier &CS = 1411 FS.getConversionSpecifier(); 1412 switch (Amt.getHowSpecified()) { 1413 case analyze_printf::OptionalAmount::Constant: 1414 S.Diag(getLocationOfByte(Amt.getStart()), 1415 diag::warn_printf_nonsensical_optional_amount) 1416 << type 1417 << CS.toString() 1418 << getSpecifierRange(startSpecifier, specifierLen) 1419 << FixItHint::CreateRemoval(getSpecifierRange(Amt.getStart(), 1420 Amt.getConstantLength())); 1421 break; 1422 1423 default: 1424 S.Diag(getLocationOfByte(Amt.getStart()), 1425 diag::warn_printf_nonsensical_optional_amount) 1426 << type 1427 << CS.toString() 1428 << getSpecifierRange(startSpecifier, specifierLen); 1429 break; 1430 } 1431} 1432 1433void CheckPrintfHandler::HandleFlag(const analyze_printf::PrintfSpecifier &FS, 1434 const analyze_printf::OptionalFlag &flag, 1435 const char *startSpecifier, 1436 unsigned specifierLen) { 1437 // Warn about pointless flag with a fixit removal. 1438 const analyze_printf::PrintfConversionSpecifier &CS = 1439 FS.getConversionSpecifier(); 1440 S.Diag(getLocationOfByte(flag.getPosition()), 1441 diag::warn_printf_nonsensical_flag) 1442 << flag.toString() << CS.toString() 1443 << getSpecifierRange(startSpecifier, specifierLen) 1444 << FixItHint::CreateRemoval(getSpecifierRange(flag.getPosition(), 1)); 1445} 1446 1447void CheckPrintfHandler::HandleIgnoredFlag( 1448 const analyze_printf::PrintfSpecifier &FS, 1449 const analyze_printf::OptionalFlag &ignoredFlag, 1450 const analyze_printf::OptionalFlag &flag, 1451 const char *startSpecifier, 1452 unsigned specifierLen) { 1453 // Warn about ignored flag with a fixit removal. 1454 S.Diag(getLocationOfByte(ignoredFlag.getPosition()), 1455 diag::warn_printf_ignored_flag) 1456 << ignoredFlag.toString() << flag.toString() 1457 << getSpecifierRange(startSpecifier, specifierLen) 1458 << FixItHint::CreateRemoval(getSpecifierRange( 1459 ignoredFlag.getPosition(), 1)); 1460} 1461 1462bool 1463CheckPrintfHandler::HandlePrintfSpecifier(const analyze_printf::PrintfSpecifier 1464 &FS, 1465 const char *startSpecifier, 1466 unsigned specifierLen) { 1467 1468 using namespace analyze_format_string; 1469 using namespace analyze_printf; 1470 const PrintfConversionSpecifier &CS = FS.getConversionSpecifier(); 1471 1472 if (FS.consumesDataArgument()) { 1473 if (atFirstArg) { 1474 atFirstArg = false; 1475 usesPositionalArgs = FS.usesPositionalArg(); 1476 } 1477 else if (usesPositionalArgs != FS.usesPositionalArg()) { 1478 // Cannot mix-and-match positional and non-positional arguments. 1479 S.Diag(getLocationOfByte(CS.getStart()), 1480 diag::warn_format_mix_positional_nonpositional_args) 1481 << getSpecifierRange(startSpecifier, specifierLen); 1482 return false; 1483 } 1484 } 1485 1486 // First check if the field width, precision, and conversion specifier 1487 // have matching data arguments. 1488 if (!HandleAmount(FS.getFieldWidth(), /* field width */ 0, 1489 startSpecifier, specifierLen)) { 1490 return false; 1491 } 1492 1493 if (!HandleAmount(FS.getPrecision(), /* precision */ 1, 1494 startSpecifier, specifierLen)) { 1495 return false; 1496 } 1497 1498 if (!CS.consumesDataArgument()) { 1499 // FIXME: Technically specifying a precision or field width here 1500 // makes no sense. Worth issuing a warning at some point. 1501 return true; 1502 } 1503 1504 // Consume the argument. 1505 unsigned argIndex = FS.getArgIndex(); 1506 if (argIndex < NumDataArgs) { 1507 // The check to see if the argIndex is valid will come later. 1508 // We set the bit here because we may exit early from this 1509 // function if we encounter some other error. 1510 CoveredArgs.set(argIndex); 1511 } 1512 1513 // Check for using an Objective-C specific conversion specifier 1514 // in a non-ObjC literal. 1515 if (!IsObjCLiteral && CS.isObjCArg()) { 1516 return HandleInvalidPrintfConversionSpecifier(FS, startSpecifier, 1517 specifierLen); 1518 } 1519 1520 // Check for invalid use of field width 1521 if (!FS.hasValidFieldWidth()) { 1522 HandleInvalidAmount(FS, FS.getFieldWidth(), /* field width */ 0, 1523 startSpecifier, specifierLen); 1524 } 1525 1526 // Check for invalid use of precision 1527 if (!FS.hasValidPrecision()) { 1528 HandleInvalidAmount(FS, FS.getPrecision(), /* precision */ 1, 1529 startSpecifier, specifierLen); 1530 } 1531 1532 // Check each flag does not conflict with any other component. 1533 if (!FS.hasValidLeadingZeros()) 1534 HandleFlag(FS, FS.hasLeadingZeros(), startSpecifier, specifierLen); 1535 if (!FS.hasValidPlusPrefix()) 1536 HandleFlag(FS, FS.hasPlusPrefix(), startSpecifier, specifierLen); 1537 if (!FS.hasValidSpacePrefix()) 1538 HandleFlag(FS, FS.hasSpacePrefix(), startSpecifier, specifierLen); 1539 if (!FS.hasValidAlternativeForm()) 1540 HandleFlag(FS, FS.hasAlternativeForm(), startSpecifier, specifierLen); 1541 if (!FS.hasValidLeftJustified()) 1542 HandleFlag(FS, FS.isLeftJustified(), startSpecifier, specifierLen); 1543 1544 // Check that flags are not ignored by another flag 1545 if (FS.hasSpacePrefix() && FS.hasPlusPrefix()) // ' ' ignored by '+' 1546 HandleIgnoredFlag(FS, FS.hasSpacePrefix(), FS.hasPlusPrefix(), 1547 startSpecifier, specifierLen); 1548 if (FS.hasLeadingZeros() && FS.isLeftJustified()) // '0' ignored by '-' 1549 HandleIgnoredFlag(FS, FS.hasLeadingZeros(), FS.isLeftJustified(), 1550 startSpecifier, specifierLen); 1551 1552 // Check the length modifier is valid with the given conversion specifier. 1553 const LengthModifier &LM = FS.getLengthModifier(); 1554 if (!FS.hasValidLengthModifier()) 1555 S.Diag(getLocationOfByte(LM.getStart()), 1556 diag::warn_format_nonsensical_length) 1557 << LM.toString() << CS.toString() 1558 << getSpecifierRange(startSpecifier, specifierLen) 1559 << FixItHint::CreateRemoval(getSpecifierRange(LM.getStart(), 1560 LM.getLength())); 1561 1562 // Are we using '%n'? 1563 if (CS.getKind() == ConversionSpecifier::nArg) { 1564 // Issue a warning about this being a possible security issue. 1565 S.Diag(getLocationOfByte(CS.getStart()), diag::warn_printf_write_back) 1566 << getSpecifierRange(startSpecifier, specifierLen); 1567 // Continue checking the other format specifiers. 1568 return true; 1569 } 1570 1571 // The remaining checks depend on the data arguments. 1572 if (HasVAListArg) 1573 return true; 1574 1575 if (!CheckNumArgs(FS, CS, startSpecifier, specifierLen, argIndex)) 1576 return false; 1577 1578 // Now type check the data expression that matches the 1579 // format specifier. 1580 const Expr *Ex = getDataArg(argIndex); 1581 const analyze_printf::ArgTypeResult &ATR = FS.getArgType(S.Context); 1582 if (ATR.isValid() && !ATR.matchesType(S.Context, Ex->getType())) { 1583 // Check if we didn't match because of an implicit cast from a 'char' 1584 // or 'short' to an 'int'. This is done because printf is a varargs 1585 // function. 1586 if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(Ex)) 1587 if (ICE->getType() == S.Context.IntTy) 1588 if (ATR.matchesType(S.Context, ICE->getSubExpr()->getType())) 1589 return true; 1590 1591 // We may be able to offer a FixItHint if it is a supported type. 1592 PrintfSpecifier fixedFS = FS; 1593 bool success = fixedFS.fixType(Ex->getType()); 1594 1595 if (success) { 1596 // Get the fix string from the fixed format specifier 1597 llvm::SmallString<128> buf; 1598 llvm::raw_svector_ostream os(buf); 1599 fixedFS.toString(os); 1600 1601 // FIXME: getRepresentativeType() perhaps should return a string 1602 // instead of a QualType to better handle when the representative 1603 // type is 'wint_t' (which is defined in the system headers). 1604 S.Diag(getLocationOfByte(CS.getStart()), 1605 diag::warn_printf_conversion_argument_type_mismatch) 1606 << ATR.getRepresentativeType(S.Context) << Ex->getType() 1607 << getSpecifierRange(startSpecifier, specifierLen) 1608 << Ex->getSourceRange() 1609 << FixItHint::CreateReplacement( 1610 getSpecifierRange(startSpecifier, specifierLen), 1611 os.str()); 1612 } 1613 else { 1614 S.Diag(getLocationOfByte(CS.getStart()), 1615 diag::warn_printf_conversion_argument_type_mismatch) 1616 << ATR.getRepresentativeType(S.Context) << Ex->getType() 1617 << getSpecifierRange(startSpecifier, specifierLen) 1618 << Ex->getSourceRange(); 1619 } 1620 } 1621 1622 return true; 1623} 1624 1625//===--- CHECK: Scanf format string checking ------------------------------===// 1626 1627namespace { 1628class CheckScanfHandler : public CheckFormatHandler { 1629public: 1630 CheckScanfHandler(Sema &s, const StringLiteral *fexpr, 1631 const Expr *origFormatExpr, unsigned firstDataArg, 1632 unsigned numDataArgs, bool isObjCLiteral, 1633 const char *beg, bool hasVAListArg, 1634 const CallExpr *theCall, unsigned formatIdx) 1635 : CheckFormatHandler(s, fexpr, origFormatExpr, firstDataArg, 1636 numDataArgs, isObjCLiteral, beg, hasVAListArg, 1637 theCall, formatIdx) {} 1638 1639 bool HandleScanfSpecifier(const analyze_scanf::ScanfSpecifier &FS, 1640 const char *startSpecifier, 1641 unsigned specifierLen); 1642 1643 bool HandleInvalidScanfConversionSpecifier( 1644 const analyze_scanf::ScanfSpecifier &FS, 1645 const char *startSpecifier, 1646 unsigned specifierLen); 1647 1648 void HandleIncompleteScanList(const char *start, const char *end); 1649}; 1650} 1651 1652void CheckScanfHandler::HandleIncompleteScanList(const char *start, 1653 const char *end) { 1654 S.Diag(getLocationOfByte(end), diag::warn_scanf_scanlist_incomplete) 1655 << getSpecifierRange(start, end - start); 1656} 1657 1658bool CheckScanfHandler::HandleInvalidScanfConversionSpecifier( 1659 const analyze_scanf::ScanfSpecifier &FS, 1660 const char *startSpecifier, 1661 unsigned specifierLen) { 1662 1663 const analyze_scanf::ScanfConversionSpecifier &CS = 1664 FS.getConversionSpecifier(); 1665 1666 return HandleInvalidConversionSpecifier(FS.getArgIndex(), 1667 getLocationOfByte(CS.getStart()), 1668 startSpecifier, specifierLen, 1669 CS.getStart(), CS.getLength()); 1670} 1671 1672bool CheckScanfHandler::HandleScanfSpecifier( 1673 const analyze_scanf::ScanfSpecifier &FS, 1674 const char *startSpecifier, 1675 unsigned specifierLen) { 1676 1677 using namespace analyze_scanf; 1678 using namespace analyze_format_string; 1679 1680 const ScanfConversionSpecifier &CS = FS.getConversionSpecifier(); 1681 1682 // Handle case where '%' and '*' don't consume an argument. These shouldn't 1683 // be used to decide if we are using positional arguments consistently. 1684 if (FS.consumesDataArgument()) { 1685 if (atFirstArg) { 1686 atFirstArg = false; 1687 usesPositionalArgs = FS.usesPositionalArg(); 1688 } 1689 else if (usesPositionalArgs != FS.usesPositionalArg()) { 1690 // Cannot mix-and-match positional and non-positional arguments. 1691 S.Diag(getLocationOfByte(CS.getStart()), 1692 diag::warn_format_mix_positional_nonpositional_args) 1693 << getSpecifierRange(startSpecifier, specifierLen); 1694 return false; 1695 } 1696 } 1697 1698 // Check if the field with is non-zero. 1699 const OptionalAmount &Amt = FS.getFieldWidth(); 1700 if (Amt.getHowSpecified() == OptionalAmount::Constant) { 1701 if (Amt.getConstantAmount() == 0) { 1702 const CharSourceRange &R = getSpecifierRange(Amt.getStart(), 1703 Amt.getConstantLength()); 1704 S.Diag(getLocationOfByte(Amt.getStart()), 1705 diag::warn_scanf_nonzero_width) 1706 << R << FixItHint::CreateRemoval(R); 1707 } 1708 } 1709 1710 if (!FS.consumesDataArgument()) { 1711 // FIXME: Technically specifying a precision or field width here 1712 // makes no sense. Worth issuing a warning at some point. 1713 return true; 1714 } 1715 1716 // Consume the argument. 1717 unsigned argIndex = FS.getArgIndex(); 1718 if (argIndex < NumDataArgs) { 1719 // The check to see if the argIndex is valid will come later. 1720 // We set the bit here because we may exit early from this 1721 // function if we encounter some other error. 1722 CoveredArgs.set(argIndex); 1723 } 1724 1725 // Check the length modifier is valid with the given conversion specifier. 1726 const LengthModifier &LM = FS.getLengthModifier(); 1727 if (!FS.hasValidLengthModifier()) { 1728 S.Diag(getLocationOfByte(LM.getStart()), 1729 diag::warn_format_nonsensical_length) 1730 << LM.toString() << CS.toString() 1731 << getSpecifierRange(startSpecifier, specifierLen) 1732 << FixItHint::CreateRemoval(getSpecifierRange(LM.getStart(), 1733 LM.getLength())); 1734 } 1735 1736 // The remaining checks depend on the data arguments. 1737 if (HasVAListArg) 1738 return true; 1739 1740 if (!CheckNumArgs(FS, CS, startSpecifier, specifierLen, argIndex)) 1741 return false; 1742 1743 // FIXME: Check that the argument type matches the format specifier. 1744 1745 return true; 1746} 1747 1748void Sema::CheckFormatString(const StringLiteral *FExpr, 1749 const Expr *OrigFormatExpr, 1750 const CallExpr *TheCall, bool HasVAListArg, 1751 unsigned format_idx, unsigned firstDataArg, 1752 bool isPrintf) { 1753 1754 // CHECK: is the format string a wide literal? 1755 if (FExpr->isWide()) { 1756 Diag(FExpr->getLocStart(), 1757 diag::warn_format_string_is_wide_literal) 1758 << OrigFormatExpr->getSourceRange(); 1759 return; 1760 } 1761 1762 // Str - The format string. NOTE: this is NOT null-terminated! 1763 llvm::StringRef StrRef = FExpr->getString(); 1764 const char *Str = StrRef.data(); 1765 unsigned StrLen = StrRef.size(); 1766 1767 // CHECK: empty format string? 1768 if (StrLen == 0) { 1769 Diag(FExpr->getLocStart(), diag::warn_empty_format_string) 1770 << OrigFormatExpr->getSourceRange(); 1771 return; 1772 } 1773 1774 if (isPrintf) { 1775 CheckPrintfHandler H(*this, FExpr, OrigFormatExpr, firstDataArg, 1776 TheCall->getNumArgs() - firstDataArg, 1777 isa<ObjCStringLiteral>(OrigFormatExpr), Str, 1778 HasVAListArg, TheCall, format_idx); 1779 1780 if (!analyze_format_string::ParsePrintfString(H, Str, Str + StrLen)) 1781 H.DoneProcessing(); 1782 } 1783 else { 1784 CheckScanfHandler H(*this, FExpr, OrigFormatExpr, firstDataArg, 1785 TheCall->getNumArgs() - firstDataArg, 1786 isa<ObjCStringLiteral>(OrigFormatExpr), Str, 1787 HasVAListArg, TheCall, format_idx); 1788 1789 if (!analyze_format_string::ParseScanfString(H, Str, Str + StrLen)) 1790 H.DoneProcessing(); 1791 } 1792} 1793 1794//===--- CHECK: Return Address of Stack Variable --------------------------===// 1795 1796static DeclRefExpr* EvalVal(Expr *E); 1797static DeclRefExpr* EvalAddr(Expr* E); 1798 1799/// CheckReturnStackAddr - Check if a return statement returns the address 1800/// of a stack variable. 1801void 1802Sema::CheckReturnStackAddr(Expr *RetValExp, QualType lhsType, 1803 SourceLocation ReturnLoc) { 1804 1805 // Perform checking for returned stack addresses. 1806 if (lhsType->isPointerType() || lhsType->isBlockPointerType()) { 1807 if (DeclRefExpr *DR = EvalAddr(RetValExp)) 1808 Diag(DR->getLocStart(), diag::warn_ret_stack_addr) 1809 << DR->getDecl()->getDeclName() << RetValExp->getSourceRange(); 1810 1811 // Skip over implicit cast expressions when checking for block expressions. 1812 RetValExp = RetValExp->IgnoreParenCasts(); 1813 1814 if (BlockExpr *C = dyn_cast<BlockExpr>(RetValExp)) 1815 if (C->hasBlockDeclRefExprs()) 1816 Diag(C->getLocStart(), diag::err_ret_local_block) 1817 << C->getSourceRange(); 1818 1819 if (AddrLabelExpr *ALE = dyn_cast<AddrLabelExpr>(RetValExp)) 1820 Diag(ALE->getLocStart(), diag::warn_ret_addr_label) 1821 << ALE->getSourceRange(); 1822 1823 } else if (lhsType->isReferenceType()) { 1824 // Perform checking for stack values returned by reference. 1825 // Check for a reference to the stack 1826 if (DeclRefExpr *DR = EvalVal(RetValExp)) 1827 Diag(DR->getLocStart(), diag::warn_ret_stack_ref) 1828 << DR->getDecl()->getDeclName() << RetValExp->getSourceRange(); 1829 } 1830} 1831 1832/// EvalAddr - EvalAddr and EvalVal are mutually recursive functions that 1833/// check if the expression in a return statement evaluates to an address 1834/// to a location on the stack. The recursion is used to traverse the 1835/// AST of the return expression, with recursion backtracking when we 1836/// encounter a subexpression that (1) clearly does not lead to the address 1837/// of a stack variable or (2) is something we cannot determine leads to 1838/// the address of a stack variable based on such local checking. 1839/// 1840/// EvalAddr processes expressions that are pointers that are used as 1841/// references (and not L-values). EvalVal handles all other values. 1842/// At the base case of the recursion is a check for a DeclRefExpr* in 1843/// the refers to a stack variable. 1844/// 1845/// This implementation handles: 1846/// 1847/// * pointer-to-pointer casts 1848/// * implicit conversions from array references to pointers 1849/// * taking the address of fields 1850/// * arbitrary interplay between "&" and "*" operators 1851/// * pointer arithmetic from an address of a stack variable 1852/// * taking the address of an array element where the array is on the stack 1853static DeclRefExpr* EvalAddr(Expr *E) { 1854 // We should only be called for evaluating pointer expressions. 1855 assert((E->getType()->isAnyPointerType() || 1856 E->getType()->isBlockPointerType() || 1857 E->getType()->isObjCQualifiedIdType()) && 1858 "EvalAddr only works on pointers"); 1859 1860 // Our "symbolic interpreter" is just a dispatch off the currently 1861 // viewed AST node. We then recursively traverse the AST by calling 1862 // EvalAddr and EvalVal appropriately. 1863 switch (E->getStmtClass()) { 1864 case Stmt::ParenExprClass: 1865 // Ignore parentheses. 1866 return EvalAddr(cast<ParenExpr>(E)->getSubExpr()); 1867 1868 case Stmt::UnaryOperatorClass: { 1869 // The only unary operator that make sense to handle here 1870 // is AddrOf. All others don't make sense as pointers. 1871 UnaryOperator *U = cast<UnaryOperator>(E); 1872 1873 if (U->getOpcode() == UnaryOperator::AddrOf) 1874 return EvalVal(U->getSubExpr()); 1875 else 1876 return NULL; 1877 } 1878 1879 case Stmt::BinaryOperatorClass: { 1880 // Handle pointer arithmetic. All other binary operators are not valid 1881 // in this context. 1882 BinaryOperator *B = cast<BinaryOperator>(E); 1883 BinaryOperator::Opcode op = B->getOpcode(); 1884 1885 if (op != BinaryOperator::Add && op != BinaryOperator::Sub) 1886 return NULL; 1887 1888 Expr *Base = B->getLHS(); 1889 1890 // Determine which argument is the real pointer base. It could be 1891 // the RHS argument instead of the LHS. 1892 if (!Base->getType()->isPointerType()) Base = B->getRHS(); 1893 1894 assert (Base->getType()->isPointerType()); 1895 return EvalAddr(Base); 1896 } 1897 1898 // For conditional operators we need to see if either the LHS or RHS are 1899 // valid DeclRefExpr*s. If one of them is valid, we return it. 1900 case Stmt::ConditionalOperatorClass: { 1901 ConditionalOperator *C = cast<ConditionalOperator>(E); 1902 1903 // Handle the GNU extension for missing LHS. 1904 if (Expr *lhsExpr = C->getLHS()) 1905 if (DeclRefExpr* LHS = EvalAddr(lhsExpr)) 1906 return LHS; 1907 1908 return EvalAddr(C->getRHS()); 1909 } 1910 1911 // For casts, we need to handle conversions from arrays to 1912 // pointer values, and pointer-to-pointer conversions. 1913 case Stmt::ImplicitCastExprClass: 1914 case Stmt::CStyleCastExprClass: 1915 case Stmt::CXXFunctionalCastExprClass: { 1916 Expr* SubExpr = cast<CastExpr>(E)->getSubExpr(); 1917 QualType T = SubExpr->getType(); 1918 1919 if (SubExpr->getType()->isPointerType() || 1920 SubExpr->getType()->isBlockPointerType() || 1921 SubExpr->getType()->isObjCQualifiedIdType()) 1922 return EvalAddr(SubExpr); 1923 else if (T->isArrayType()) 1924 return EvalVal(SubExpr); 1925 else 1926 return 0; 1927 } 1928 1929 // C++ casts. For dynamic casts, static casts, and const casts, we 1930 // are always converting from a pointer-to-pointer, so we just blow 1931 // through the cast. In the case the dynamic cast doesn't fail (and 1932 // return NULL), we take the conservative route and report cases 1933 // where we return the address of a stack variable. For Reinterpre 1934 // FIXME: The comment about is wrong; we're not always converting 1935 // from pointer to pointer. I'm guessing that this code should also 1936 // handle references to objects. 1937 case Stmt::CXXStaticCastExprClass: 1938 case Stmt::CXXDynamicCastExprClass: 1939 case Stmt::CXXConstCastExprClass: 1940 case Stmt::CXXReinterpretCastExprClass: { 1941 Expr *S = cast<CXXNamedCastExpr>(E)->getSubExpr(); 1942 if (S->getType()->isPointerType() || S->getType()->isBlockPointerType()) 1943 return EvalAddr(S); 1944 else 1945 return NULL; 1946 } 1947 1948 // Everything else: we simply don't reason about them. 1949 default: 1950 return NULL; 1951 } 1952} 1953 1954 1955/// EvalVal - This function is complements EvalAddr in the mutual recursion. 1956/// See the comments for EvalAddr for more details. 1957static DeclRefExpr* EvalVal(Expr *E) { 1958do { 1959 // We should only be called for evaluating non-pointer expressions, or 1960 // expressions with a pointer type that are not used as references but instead 1961 // are l-values (e.g., DeclRefExpr with a pointer type). 1962 1963 // Our "symbolic interpreter" is just a dispatch off the currently 1964 // viewed AST node. We then recursively traverse the AST by calling 1965 // EvalAddr and EvalVal appropriately. 1966 switch (E->getStmtClass()) { 1967 case Stmt::ImplicitCastExprClass: { 1968 ImplicitCastExpr *IE = cast<ImplicitCastExpr>(E); 1969 if (IE->getValueKind() == VK_LValue) { 1970 E = IE->getSubExpr(); 1971 continue; 1972 } 1973 return NULL; 1974 } 1975 1976 case Stmt::DeclRefExprClass: { 1977 // DeclRefExpr: the base case. When we hit a DeclRefExpr we are looking 1978 // at code that refers to a variable's name. We check if it has local 1979 // storage within the function, and if so, return the expression. 1980 DeclRefExpr *DR = cast<DeclRefExpr>(E); 1981 1982 if (VarDecl *V = dyn_cast<VarDecl>(DR->getDecl())) 1983 if (V->hasLocalStorage() && !V->getType()->isReferenceType()) return DR; 1984 1985 return NULL; 1986 } 1987 1988 case Stmt::ParenExprClass: { 1989 // Ignore parentheses. 1990 E = cast<ParenExpr>(E)->getSubExpr(); 1991 continue; 1992 } 1993 1994 case Stmt::UnaryOperatorClass: { 1995 // The only unary operator that make sense to handle here 1996 // is Deref. All others don't resolve to a "name." This includes 1997 // handling all sorts of rvalues passed to a unary operator. 1998 UnaryOperator *U = cast<UnaryOperator>(E); 1999 2000 if (U->getOpcode() == UnaryOperator::Deref) 2001 return EvalAddr(U->getSubExpr()); 2002 2003 return NULL; 2004 } 2005 2006 case Stmt::ArraySubscriptExprClass: { 2007 // Array subscripts are potential references to data on the stack. We 2008 // retrieve the DeclRefExpr* for the array variable if it indeed 2009 // has local storage. 2010 return EvalAddr(cast<ArraySubscriptExpr>(E)->getBase()); 2011 } 2012 2013 case Stmt::ConditionalOperatorClass: { 2014 // For conditional operators we need to see if either the LHS or RHS are 2015 // non-NULL DeclRefExpr's. If one is non-NULL, we return it. 2016 ConditionalOperator *C = cast<ConditionalOperator>(E); 2017 2018 // Handle the GNU extension for missing LHS. 2019 if (Expr *lhsExpr = C->getLHS()) 2020 if (DeclRefExpr *LHS = EvalVal(lhsExpr)) 2021 return LHS; 2022 2023 return EvalVal(C->getRHS()); 2024 } 2025 2026 // Accesses to members are potential references to data on the stack. 2027 case Stmt::MemberExprClass: { 2028 MemberExpr *M = cast<MemberExpr>(E); 2029 2030 // Check for indirect access. We only want direct field accesses. 2031 if (!M->isArrow()) 2032 return EvalVal(M->getBase()); 2033 else 2034 return NULL; 2035 } 2036 2037 // Everything else: we simply don't reason about them. 2038 default: 2039 return NULL; 2040 } 2041} while (true); 2042} 2043 2044//===--- CHECK: Floating-Point comparisons (-Wfloat-equal) ---------------===// 2045 2046/// Check for comparisons of floating point operands using != and ==. 2047/// Issue a warning if these are no self-comparisons, as they are not likely 2048/// to do what the programmer intended. 2049void Sema::CheckFloatComparison(SourceLocation loc, Expr* lex, Expr *rex) { 2050 bool EmitWarning = true; 2051 2052 Expr* LeftExprSansParen = lex->IgnoreParens(); 2053 Expr* RightExprSansParen = rex->IgnoreParens(); 2054 2055 // Special case: check for x == x (which is OK). 2056 // Do not emit warnings for such cases. 2057 if (DeclRefExpr* DRL = dyn_cast<DeclRefExpr>(LeftExprSansParen)) 2058 if (DeclRefExpr* DRR = dyn_cast<DeclRefExpr>(RightExprSansParen)) 2059 if (DRL->getDecl() == DRR->getDecl()) 2060 EmitWarning = false; 2061 2062 2063 // Special case: check for comparisons against literals that can be exactly 2064 // represented by APFloat. In such cases, do not emit a warning. This 2065 // is a heuristic: often comparison against such literals are used to 2066 // detect if a value in a variable has not changed. This clearly can 2067 // lead to false negatives. 2068 if (EmitWarning) { 2069 if (FloatingLiteral* FLL = dyn_cast<FloatingLiteral>(LeftExprSansParen)) { 2070 if (FLL->isExact()) 2071 EmitWarning = false; 2072 } else 2073 if (FloatingLiteral* FLR = dyn_cast<FloatingLiteral>(RightExprSansParen)){ 2074 if (FLR->isExact()) 2075 EmitWarning = false; 2076 } 2077 } 2078 2079 // Check for comparisons with builtin types. 2080 if (EmitWarning) 2081 if (CallExpr* CL = dyn_cast<CallExpr>(LeftExprSansParen)) 2082 if (CL->isBuiltinCall(Context)) 2083 EmitWarning = false; 2084 2085 if (EmitWarning) 2086 if (CallExpr* CR = dyn_cast<CallExpr>(RightExprSansParen)) 2087 if (CR->isBuiltinCall(Context)) 2088 EmitWarning = false; 2089 2090 // Emit the diagnostic. 2091 if (EmitWarning) 2092 Diag(loc, diag::warn_floatingpoint_eq) 2093 << lex->getSourceRange() << rex->getSourceRange(); 2094} 2095 2096//===--- CHECK: Integer mixed-sign comparisons (-Wsign-compare) --------===// 2097//===--- CHECK: Lossy implicit conversions (-Wconversion) --------------===// 2098 2099namespace { 2100 2101/// Structure recording the 'active' range of an integer-valued 2102/// expression. 2103struct IntRange { 2104 /// The number of bits active in the int. 2105 unsigned Width; 2106 2107 /// True if the int is known not to have negative values. 2108 bool NonNegative; 2109 2110 IntRange(unsigned Width, bool NonNegative) 2111 : Width(Width), NonNegative(NonNegative) 2112 {} 2113 2114 // Returns the range of the bool type. 2115 static IntRange forBoolType() { 2116 return IntRange(1, true); 2117 } 2118 2119 // Returns the range of an integral type. 2120 static IntRange forType(ASTContext &C, QualType T) { 2121 return forCanonicalType(C, T->getCanonicalTypeInternal().getTypePtr()); 2122 } 2123 2124 // Returns the range of an integeral type based on its canonical 2125 // representation. 2126 static IntRange forCanonicalType(ASTContext &C, const Type *T) { 2127 assert(T->isCanonicalUnqualified()); 2128 2129 if (const VectorType *VT = dyn_cast<VectorType>(T)) 2130 T = VT->getElementType().getTypePtr(); 2131 if (const ComplexType *CT = dyn_cast<ComplexType>(T)) 2132 T = CT->getElementType().getTypePtr(); 2133 2134 if (const EnumType *ET = dyn_cast<EnumType>(T)) { 2135 EnumDecl *Enum = ET->getDecl(); 2136 unsigned NumPositive = Enum->getNumPositiveBits(); 2137 unsigned NumNegative = Enum->getNumNegativeBits(); 2138 2139 return IntRange(std::max(NumPositive, NumNegative), NumNegative == 0); 2140 } 2141 2142 const BuiltinType *BT = cast<BuiltinType>(T); 2143 assert(BT->isInteger()); 2144 2145 return IntRange(C.getIntWidth(QualType(T, 0)), BT->isUnsignedInteger()); 2146 } 2147 2148 // Returns the supremum of two ranges: i.e. their conservative merge. 2149 static IntRange join(IntRange L, IntRange R) { 2150 return IntRange(std::max(L.Width, R.Width), 2151 L.NonNegative && R.NonNegative); 2152 } 2153 2154 // Returns the infinum of two ranges: i.e. their aggressive merge. 2155 static IntRange meet(IntRange L, IntRange R) { 2156 return IntRange(std::min(L.Width, R.Width), 2157 L.NonNegative || R.NonNegative); 2158 } 2159}; 2160 2161IntRange GetValueRange(ASTContext &C, llvm::APSInt &value, unsigned MaxWidth) { 2162 if (value.isSigned() && value.isNegative()) 2163 return IntRange(value.getMinSignedBits(), false); 2164 2165 if (value.getBitWidth() > MaxWidth) 2166 value.trunc(MaxWidth); 2167 2168 // isNonNegative() just checks the sign bit without considering 2169 // signedness. 2170 return IntRange(value.getActiveBits(), true); 2171} 2172 2173IntRange GetValueRange(ASTContext &C, APValue &result, QualType Ty, 2174 unsigned MaxWidth) { 2175 if (result.isInt()) 2176 return GetValueRange(C, result.getInt(), MaxWidth); 2177 2178 if (result.isVector()) { 2179 IntRange R = GetValueRange(C, result.getVectorElt(0), Ty, MaxWidth); 2180 for (unsigned i = 1, e = result.getVectorLength(); i != e; ++i) { 2181 IntRange El = GetValueRange(C, result.getVectorElt(i), Ty, MaxWidth); 2182 R = IntRange::join(R, El); 2183 } 2184 return R; 2185 } 2186 2187 if (result.isComplexInt()) { 2188 IntRange R = GetValueRange(C, result.getComplexIntReal(), MaxWidth); 2189 IntRange I = GetValueRange(C, result.getComplexIntImag(), MaxWidth); 2190 return IntRange::join(R, I); 2191 } 2192 2193 // This can happen with lossless casts to intptr_t of "based" lvalues. 2194 // Assume it might use arbitrary bits. 2195 // FIXME: The only reason we need to pass the type in here is to get 2196 // the sign right on this one case. It would be nice if APValue 2197 // preserved this. 2198 assert(result.isLValue()); 2199 return IntRange(MaxWidth, Ty->isUnsignedIntegerType()); 2200} 2201 2202/// Pseudo-evaluate the given integer expression, estimating the 2203/// range of values it might take. 2204/// 2205/// \param MaxWidth - the width to which the value will be truncated 2206IntRange GetExprRange(ASTContext &C, Expr *E, unsigned MaxWidth) { 2207 E = E->IgnoreParens(); 2208 2209 // Try a full evaluation first. 2210 Expr::EvalResult result; 2211 if (E->Evaluate(result, C)) 2212 return GetValueRange(C, result.Val, E->getType(), MaxWidth); 2213 2214 // I think we only want to look through implicit casts here; if the 2215 // user has an explicit widening cast, we should treat the value as 2216 // being of the new, wider type. 2217 if (ImplicitCastExpr *CE = dyn_cast<ImplicitCastExpr>(E)) { 2218 if (CE->getCastKind() == CastExpr::CK_NoOp) 2219 return GetExprRange(C, CE->getSubExpr(), MaxWidth); 2220 2221 IntRange OutputTypeRange = IntRange::forType(C, CE->getType()); 2222 2223 bool isIntegerCast = (CE->getCastKind() == CastExpr::CK_IntegralCast); 2224 if (!isIntegerCast && CE->getCastKind() == CastExpr::CK_Unknown) 2225 isIntegerCast = CE->getSubExpr()->getType()->isIntegerType(); 2226 2227 // Assume that non-integer casts can span the full range of the type. 2228 if (!isIntegerCast) 2229 return OutputTypeRange; 2230 2231 IntRange SubRange 2232 = GetExprRange(C, CE->getSubExpr(), 2233 std::min(MaxWidth, OutputTypeRange.Width)); 2234 2235 // Bail out if the subexpr's range is as wide as the cast type. 2236 if (SubRange.Width >= OutputTypeRange.Width) 2237 return OutputTypeRange; 2238 2239 // Otherwise, we take the smaller width, and we're non-negative if 2240 // either the output type or the subexpr is. 2241 return IntRange(SubRange.Width, 2242 SubRange.NonNegative || OutputTypeRange.NonNegative); 2243 } 2244 2245 if (ConditionalOperator *CO = dyn_cast<ConditionalOperator>(E)) { 2246 // If we can fold the condition, just take that operand. 2247 bool CondResult; 2248 if (CO->getCond()->EvaluateAsBooleanCondition(CondResult, C)) 2249 return GetExprRange(C, CondResult ? CO->getTrueExpr() 2250 : CO->getFalseExpr(), 2251 MaxWidth); 2252 2253 // Otherwise, conservatively merge. 2254 IntRange L = GetExprRange(C, CO->getTrueExpr(), MaxWidth); 2255 IntRange R = GetExprRange(C, CO->getFalseExpr(), MaxWidth); 2256 return IntRange::join(L, R); 2257 } 2258 2259 if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) { 2260 switch (BO->getOpcode()) { 2261 2262 // Boolean-valued operations are single-bit and positive. 2263 case BinaryOperator::LAnd: 2264 case BinaryOperator::LOr: 2265 case BinaryOperator::LT: 2266 case BinaryOperator::GT: 2267 case BinaryOperator::LE: 2268 case BinaryOperator::GE: 2269 case BinaryOperator::EQ: 2270 case BinaryOperator::NE: 2271 return IntRange::forBoolType(); 2272 2273 // The type of these compound assignments is the type of the LHS, 2274 // so the RHS is not necessarily an integer. 2275 case BinaryOperator::MulAssign: 2276 case BinaryOperator::DivAssign: 2277 case BinaryOperator::RemAssign: 2278 case BinaryOperator::AddAssign: 2279 case BinaryOperator::SubAssign: 2280 return IntRange::forType(C, E->getType()); 2281 2282 // Operations with opaque sources are black-listed. 2283 case BinaryOperator::PtrMemD: 2284 case BinaryOperator::PtrMemI: 2285 return IntRange::forType(C, E->getType()); 2286 2287 // Bitwise-and uses the *infinum* of the two source ranges. 2288 case BinaryOperator::And: 2289 case BinaryOperator::AndAssign: 2290 return IntRange::meet(GetExprRange(C, BO->getLHS(), MaxWidth), 2291 GetExprRange(C, BO->getRHS(), MaxWidth)); 2292 2293 // Left shift gets black-listed based on a judgement call. 2294 case BinaryOperator::Shl: 2295 // ...except that we want to treat '1 << (blah)' as logically 2296 // positive. It's an important idiom. 2297 if (IntegerLiteral *I 2298 = dyn_cast<IntegerLiteral>(BO->getLHS()->IgnoreParenCasts())) { 2299 if (I->getValue() == 1) { 2300 IntRange R = IntRange::forType(C, E->getType()); 2301 return IntRange(R.Width, /*NonNegative*/ true); 2302 } 2303 } 2304 // fallthrough 2305 2306 case BinaryOperator::ShlAssign: 2307 return IntRange::forType(C, E->getType()); 2308 2309 // Right shift by a constant can narrow its left argument. 2310 case BinaryOperator::Shr: 2311 case BinaryOperator::ShrAssign: { 2312 IntRange L = GetExprRange(C, BO->getLHS(), MaxWidth); 2313 2314 // If the shift amount is a positive constant, drop the width by 2315 // that much. 2316 llvm::APSInt shift; 2317 if (BO->getRHS()->isIntegerConstantExpr(shift, C) && 2318 shift.isNonNegative()) { 2319 unsigned zext = shift.getZExtValue(); 2320 if (zext >= L.Width) 2321 L.Width = (L.NonNegative ? 0 : 1); 2322 else 2323 L.Width -= zext; 2324 } 2325 2326 return L; 2327 } 2328 2329 // Comma acts as its right operand. 2330 case BinaryOperator::Comma: 2331 return GetExprRange(C, BO->getRHS(), MaxWidth); 2332 2333 // Black-list pointer subtractions. 2334 case BinaryOperator::Sub: 2335 if (BO->getLHS()->getType()->isPointerType()) 2336 return IntRange::forType(C, E->getType()); 2337 // fallthrough 2338 2339 default: 2340 break; 2341 } 2342 2343 // Treat every other operator as if it were closed on the 2344 // narrowest type that encompasses both operands. 2345 IntRange L = GetExprRange(C, BO->getLHS(), MaxWidth); 2346 IntRange R = GetExprRange(C, BO->getRHS(), MaxWidth); 2347 return IntRange::join(L, R); 2348 } 2349 2350 if (UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) { 2351 switch (UO->getOpcode()) { 2352 // Boolean-valued operations are white-listed. 2353 case UnaryOperator::LNot: 2354 return IntRange::forBoolType(); 2355 2356 // Operations with opaque sources are black-listed. 2357 case UnaryOperator::Deref: 2358 case UnaryOperator::AddrOf: // should be impossible 2359 return IntRange::forType(C, E->getType()); 2360 2361 default: 2362 return GetExprRange(C, UO->getSubExpr(), MaxWidth); 2363 } 2364 } 2365 2366 if (dyn_cast<OffsetOfExpr>(E)) { 2367 IntRange::forType(C, E->getType()); 2368 } 2369 2370 FieldDecl *BitField = E->getBitField(); 2371 if (BitField) { 2372 llvm::APSInt BitWidthAP = BitField->getBitWidth()->EvaluateAsInt(C); 2373 unsigned BitWidth = BitWidthAP.getZExtValue(); 2374 2375 return IntRange(BitWidth, BitField->getType()->isUnsignedIntegerType()); 2376 } 2377 2378 return IntRange::forType(C, E->getType()); 2379} 2380 2381IntRange GetExprRange(ASTContext &C, Expr *E) { 2382 return GetExprRange(C, E, C.getIntWidth(E->getType())); 2383} 2384 2385/// Checks whether the given value, which currently has the given 2386/// source semantics, has the same value when coerced through the 2387/// target semantics. 2388bool IsSameFloatAfterCast(const llvm::APFloat &value, 2389 const llvm::fltSemantics &Src, 2390 const llvm::fltSemantics &Tgt) { 2391 llvm::APFloat truncated = value; 2392 2393 bool ignored; 2394 truncated.convert(Src, llvm::APFloat::rmNearestTiesToEven, &ignored); 2395 truncated.convert(Tgt, llvm::APFloat::rmNearestTiesToEven, &ignored); 2396 2397 return truncated.bitwiseIsEqual(value); 2398} 2399 2400/// Checks whether the given value, which currently has the given 2401/// source semantics, has the same value when coerced through the 2402/// target semantics. 2403/// 2404/// The value might be a vector of floats (or a complex number). 2405bool IsSameFloatAfterCast(const APValue &value, 2406 const llvm::fltSemantics &Src, 2407 const llvm::fltSemantics &Tgt) { 2408 if (value.isFloat()) 2409 return IsSameFloatAfterCast(value.getFloat(), Src, Tgt); 2410 2411 if (value.isVector()) { 2412 for (unsigned i = 0, e = value.getVectorLength(); i != e; ++i) 2413 if (!IsSameFloatAfterCast(value.getVectorElt(i), Src, Tgt)) 2414 return false; 2415 return true; 2416 } 2417 2418 assert(value.isComplexFloat()); 2419 return (IsSameFloatAfterCast(value.getComplexFloatReal(), Src, Tgt) && 2420 IsSameFloatAfterCast(value.getComplexFloatImag(), Src, Tgt)); 2421} 2422 2423void AnalyzeImplicitConversions(Sema &S, Expr *E); 2424 2425bool IsZero(Sema &S, Expr *E) { 2426 llvm::APSInt Value; 2427 return E->isIntegerConstantExpr(Value, S.Context) && Value == 0; 2428} 2429 2430void CheckTrivialUnsignedComparison(Sema &S, BinaryOperator *E) { 2431 BinaryOperator::Opcode op = E->getOpcode(); 2432 if (op == BinaryOperator::LT && IsZero(S, E->getRHS())) { 2433 S.Diag(E->getOperatorLoc(), diag::warn_lunsigned_always_true_comparison) 2434 << "< 0" << "false" 2435 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); 2436 } else if (op == BinaryOperator::GE && IsZero(S, E->getRHS())) { 2437 S.Diag(E->getOperatorLoc(), diag::warn_lunsigned_always_true_comparison) 2438 << ">= 0" << "true" 2439 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); 2440 } else if (op == BinaryOperator::GT && IsZero(S, E->getLHS())) { 2441 S.Diag(E->getOperatorLoc(), diag::warn_runsigned_always_true_comparison) 2442 << "0 >" << "false" 2443 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); 2444 } else if (op == BinaryOperator::LE && IsZero(S, E->getLHS())) { 2445 S.Diag(E->getOperatorLoc(), diag::warn_runsigned_always_true_comparison) 2446 << "0 <=" << "true" 2447 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); 2448 } 2449} 2450 2451/// Analyze the operands of the given comparison. Implements the 2452/// fallback case from AnalyzeComparison. 2453void AnalyzeImpConvsInComparison(Sema &S, BinaryOperator *E) { 2454 AnalyzeImplicitConversions(S, E->getLHS()); 2455 AnalyzeImplicitConversions(S, E->getRHS()); 2456} 2457 2458/// \brief Implements -Wsign-compare. 2459/// 2460/// \param lex the left-hand expression 2461/// \param rex the right-hand expression 2462/// \param OpLoc the location of the joining operator 2463/// \param BinOpc binary opcode or 0 2464void AnalyzeComparison(Sema &S, BinaryOperator *E) { 2465 // The type the comparison is being performed in. 2466 QualType T = E->getLHS()->getType(); 2467 assert(S.Context.hasSameUnqualifiedType(T, E->getRHS()->getType()) 2468 && "comparison with mismatched types"); 2469 2470 // We don't do anything special if this isn't an unsigned integral 2471 // comparison: we're only interested in integral comparisons, and 2472 // signed comparisons only happen in cases we don't care to warn about. 2473 if (!T->hasUnsignedIntegerRepresentation()) 2474 return AnalyzeImpConvsInComparison(S, E); 2475 2476 Expr *lex = E->getLHS()->IgnoreParenImpCasts(); 2477 Expr *rex = E->getRHS()->IgnoreParenImpCasts(); 2478 2479 // Check to see if one of the (unmodified) operands is of different 2480 // signedness. 2481 Expr *signedOperand, *unsignedOperand; 2482 if (lex->getType()->hasSignedIntegerRepresentation()) { 2483 assert(!rex->getType()->hasSignedIntegerRepresentation() && 2484 "unsigned comparison between two signed integer expressions?"); 2485 signedOperand = lex; 2486 unsignedOperand = rex; 2487 } else if (rex->getType()->hasSignedIntegerRepresentation()) { 2488 signedOperand = rex; 2489 unsignedOperand = lex; 2490 } else { 2491 CheckTrivialUnsignedComparison(S, E); 2492 return AnalyzeImpConvsInComparison(S, E); 2493 } 2494 2495 // Otherwise, calculate the effective range of the signed operand. 2496 IntRange signedRange = GetExprRange(S.Context, signedOperand); 2497 2498 // Go ahead and analyze implicit conversions in the operands. Note 2499 // that we skip the implicit conversions on both sides. 2500 AnalyzeImplicitConversions(S, lex); 2501 AnalyzeImplicitConversions(S, rex); 2502 2503 // If the signed range is non-negative, -Wsign-compare won't fire, 2504 // but we should still check for comparisons which are always true 2505 // or false. 2506 if (signedRange.NonNegative) 2507 return CheckTrivialUnsignedComparison(S, E); 2508 2509 // For (in)equality comparisons, if the unsigned operand is a 2510 // constant which cannot collide with a overflowed signed operand, 2511 // then reinterpreting the signed operand as unsigned will not 2512 // change the result of the comparison. 2513 if (E->isEqualityOp()) { 2514 unsigned comparisonWidth = S.Context.getIntWidth(T); 2515 IntRange unsignedRange = GetExprRange(S.Context, unsignedOperand); 2516 2517 // We should never be unable to prove that the unsigned operand is 2518 // non-negative. 2519 assert(unsignedRange.NonNegative && "unsigned range includes negative?"); 2520 2521 if (unsignedRange.Width < comparisonWidth) 2522 return; 2523 } 2524 2525 S.Diag(E->getOperatorLoc(), diag::warn_mixed_sign_comparison) 2526 << lex->getType() << rex->getType() 2527 << lex->getSourceRange() << rex->getSourceRange(); 2528} 2529 2530/// Diagnose an implicit cast; purely a helper for CheckImplicitConversion. 2531void DiagnoseImpCast(Sema &S, Expr *E, QualType T, unsigned diag) { 2532 S.Diag(E->getExprLoc(), diag) << E->getType() << T << E->getSourceRange(); 2533} 2534 2535void CheckImplicitConversion(Sema &S, Expr *E, QualType T, 2536 bool *ICContext = 0) { 2537 if (E->isTypeDependent() || E->isValueDependent()) return; 2538 2539 const Type *Source = S.Context.getCanonicalType(E->getType()).getTypePtr(); 2540 const Type *Target = S.Context.getCanonicalType(T).getTypePtr(); 2541 if (Source == Target) return; 2542 if (Target->isDependentType()) return; 2543 2544 // Never diagnose implicit casts to bool. 2545 if (Target->isSpecificBuiltinType(BuiltinType::Bool)) 2546 return; 2547 2548 // Strip vector types. 2549 if (isa<VectorType>(Source)) { 2550 if (!isa<VectorType>(Target)) 2551 return DiagnoseImpCast(S, E, T, diag::warn_impcast_vector_scalar); 2552 2553 Source = cast<VectorType>(Source)->getElementType().getTypePtr(); 2554 Target = cast<VectorType>(Target)->getElementType().getTypePtr(); 2555 } 2556 2557 // Strip complex types. 2558 if (isa<ComplexType>(Source)) { 2559 if (!isa<ComplexType>(Target)) 2560 return DiagnoseImpCast(S, E, T, diag::warn_impcast_complex_scalar); 2561 2562 Source = cast<ComplexType>(Source)->getElementType().getTypePtr(); 2563 Target = cast<ComplexType>(Target)->getElementType().getTypePtr(); 2564 } 2565 2566 const BuiltinType *SourceBT = dyn_cast<BuiltinType>(Source); 2567 const BuiltinType *TargetBT = dyn_cast<BuiltinType>(Target); 2568 2569 // If the source is floating point... 2570 if (SourceBT && SourceBT->isFloatingPoint()) { 2571 // ...and the target is floating point... 2572 if (TargetBT && TargetBT->isFloatingPoint()) { 2573 // ...then warn if we're dropping FP rank. 2574 2575 // Builtin FP kinds are ordered by increasing FP rank. 2576 if (SourceBT->getKind() > TargetBT->getKind()) { 2577 // Don't warn about float constants that are precisely 2578 // representable in the target type. 2579 Expr::EvalResult result; 2580 if (E->Evaluate(result, S.Context)) { 2581 // Value might be a float, a float vector, or a float complex. 2582 if (IsSameFloatAfterCast(result.Val, 2583 S.Context.getFloatTypeSemantics(QualType(TargetBT, 0)), 2584 S.Context.getFloatTypeSemantics(QualType(SourceBT, 0)))) 2585 return; 2586 } 2587 2588 DiagnoseImpCast(S, E, T, diag::warn_impcast_float_precision); 2589 } 2590 return; 2591 } 2592 2593 // If the target is integral, always warn. 2594 if ((TargetBT && TargetBT->isInteger())) 2595 // TODO: don't warn for integer values? 2596 DiagnoseImpCast(S, E, T, diag::warn_impcast_float_integer); 2597 2598 return; 2599 } 2600 2601 if (!Source->isIntegerType() || !Target->isIntegerType()) 2602 return; 2603 2604 IntRange SourceRange = GetExprRange(S.Context, E); 2605 IntRange TargetRange = IntRange::forCanonicalType(S.Context, Target); 2606 2607 if (SourceRange.Width > TargetRange.Width) { 2608 // People want to build with -Wshorten-64-to-32 and not -Wconversion 2609 // and by god we'll let them. 2610 if (SourceRange.Width == 64 && TargetRange.Width == 32) 2611 return DiagnoseImpCast(S, E, T, diag::warn_impcast_integer_64_32); 2612 return DiagnoseImpCast(S, E, T, diag::warn_impcast_integer_precision); 2613 } 2614 2615 if ((TargetRange.NonNegative && !SourceRange.NonNegative) || 2616 (!TargetRange.NonNegative && SourceRange.NonNegative && 2617 SourceRange.Width == TargetRange.Width)) { 2618 unsigned DiagID = diag::warn_impcast_integer_sign; 2619 2620 // Traditionally, gcc has warned about this under -Wsign-compare. 2621 // We also want to warn about it in -Wconversion. 2622 // So if -Wconversion is off, use a completely identical diagnostic 2623 // in the sign-compare group. 2624 // The conditional-checking code will 2625 if (ICContext) { 2626 DiagID = diag::warn_impcast_integer_sign_conditional; 2627 *ICContext = true; 2628 } 2629 2630 return DiagnoseImpCast(S, E, T, DiagID); 2631 } 2632 2633 return; 2634} 2635 2636void CheckConditionalOperator(Sema &S, ConditionalOperator *E, QualType T); 2637 2638void CheckConditionalOperand(Sema &S, Expr *E, QualType T, 2639 bool &ICContext) { 2640 E = E->IgnoreParenImpCasts(); 2641 2642 if (isa<ConditionalOperator>(E)) 2643 return CheckConditionalOperator(S, cast<ConditionalOperator>(E), T); 2644 2645 AnalyzeImplicitConversions(S, E); 2646 if (E->getType() != T) 2647 return CheckImplicitConversion(S, E, T, &ICContext); 2648 return; 2649} 2650 2651void CheckConditionalOperator(Sema &S, ConditionalOperator *E, QualType T) { 2652 AnalyzeImplicitConversions(S, E->getCond()); 2653 2654 bool Suspicious = false; 2655 CheckConditionalOperand(S, E->getTrueExpr(), T, Suspicious); 2656 CheckConditionalOperand(S, E->getFalseExpr(), T, Suspicious); 2657 2658 // If -Wconversion would have warned about either of the candidates 2659 // for a signedness conversion to the context type... 2660 if (!Suspicious) return; 2661 2662 // ...but it's currently ignored... 2663 if (S.Diags.getDiagnosticLevel(diag::warn_impcast_integer_sign_conditional)) 2664 return; 2665 2666 // ...and -Wsign-compare isn't... 2667 if (!S.Diags.getDiagnosticLevel(diag::warn_mixed_sign_conditional)) 2668 return; 2669 2670 // ...then check whether it would have warned about either of the 2671 // candidates for a signedness conversion to the condition type. 2672 if (E->getType() != T) { 2673 Suspicious = false; 2674 CheckImplicitConversion(S, E->getTrueExpr()->IgnoreParenImpCasts(), 2675 E->getType(), &Suspicious); 2676 if (!Suspicious) 2677 CheckImplicitConversion(S, E->getFalseExpr()->IgnoreParenImpCasts(), 2678 E->getType(), &Suspicious); 2679 if (!Suspicious) 2680 return; 2681 } 2682 2683 // If so, emit a diagnostic under -Wsign-compare. 2684 Expr *lex = E->getTrueExpr()->IgnoreParenImpCasts(); 2685 Expr *rex = E->getFalseExpr()->IgnoreParenImpCasts(); 2686 S.Diag(E->getQuestionLoc(), diag::warn_mixed_sign_conditional) 2687 << lex->getType() << rex->getType() 2688 << lex->getSourceRange() << rex->getSourceRange(); 2689} 2690 2691/// AnalyzeImplicitConversions - Find and report any interesting 2692/// implicit conversions in the given expression. There are a couple 2693/// of competing diagnostics here, -Wconversion and -Wsign-compare. 2694void AnalyzeImplicitConversions(Sema &S, Expr *OrigE) { 2695 QualType T = OrigE->getType(); 2696 Expr *E = OrigE->IgnoreParenImpCasts(); 2697 2698 // For conditional operators, we analyze the arguments as if they 2699 // were being fed directly into the output. 2700 if (isa<ConditionalOperator>(E)) { 2701 ConditionalOperator *CO = cast<ConditionalOperator>(E); 2702 CheckConditionalOperator(S, CO, T); 2703 return; 2704 } 2705 2706 // Go ahead and check any implicit conversions we might have skipped. 2707 // The non-canonical typecheck is just an optimization; 2708 // CheckImplicitConversion will filter out dead implicit conversions. 2709 if (E->getType() != T) 2710 CheckImplicitConversion(S, E, T); 2711 2712 // Now continue drilling into this expression. 2713 2714 // Skip past explicit casts. 2715 if (isa<ExplicitCastExpr>(E)) { 2716 E = cast<ExplicitCastExpr>(E)->getSubExpr()->IgnoreParenImpCasts(); 2717 return AnalyzeImplicitConversions(S, E); 2718 } 2719 2720 // Do a somewhat different check with comparison operators. 2721 if (isa<BinaryOperator>(E) && cast<BinaryOperator>(E)->isComparisonOp()) 2722 return AnalyzeComparison(S, cast<BinaryOperator>(E)); 2723 2724 // These break the otherwise-useful invariant below. Fortunately, 2725 // we don't really need to recurse into them, because any internal 2726 // expressions should have been analyzed already when they were 2727 // built into statements. 2728 if (isa<StmtExpr>(E)) return; 2729 2730 // Don't descend into unevaluated contexts. 2731 if (isa<SizeOfAlignOfExpr>(E)) return; 2732 2733 // Now just recurse over the expression's children. 2734 for (Stmt::child_iterator I = E->child_begin(), IE = E->child_end(); 2735 I != IE; ++I) 2736 AnalyzeImplicitConversions(S, cast<Expr>(*I)); 2737} 2738 2739} // end anonymous namespace 2740 2741/// Diagnoses "dangerous" implicit conversions within the given 2742/// expression (which is a full expression). Implements -Wconversion 2743/// and -Wsign-compare. 2744void Sema::CheckImplicitConversions(Expr *E) { 2745 // Don't diagnose in unevaluated contexts. 2746 if (ExprEvalContexts.back().Context == Sema::Unevaluated) 2747 return; 2748 2749 // Don't diagnose for value- or type-dependent expressions. 2750 if (E->isTypeDependent() || E->isValueDependent()) 2751 return; 2752 2753 AnalyzeImplicitConversions(*this, E); 2754} 2755 2756/// CheckParmsForFunctionDef - Check that the parameters of the given 2757/// function are appropriate for the definition of a function. This 2758/// takes care of any checks that cannot be performed on the 2759/// declaration itself, e.g., that the types of each of the function 2760/// parameters are complete. 2761bool Sema::CheckParmsForFunctionDef(FunctionDecl *FD) { 2762 bool HasInvalidParm = false; 2763 for (unsigned p = 0, NumParams = FD->getNumParams(); p < NumParams; ++p) { 2764 ParmVarDecl *Param = FD->getParamDecl(p); 2765 2766 // C99 6.7.5.3p4: the parameters in a parameter type list in a 2767 // function declarator that is part of a function definition of 2768 // that function shall not have incomplete type. 2769 // 2770 // This is also C++ [dcl.fct]p6. 2771 if (!Param->isInvalidDecl() && 2772 RequireCompleteType(Param->getLocation(), Param->getType(), 2773 diag::err_typecheck_decl_incomplete_type)) { 2774 Param->setInvalidDecl(); 2775 HasInvalidParm = true; 2776 } 2777 2778 // C99 6.9.1p5: If the declarator includes a parameter type list, the 2779 // declaration of each parameter shall include an identifier. 2780 if (Param->getIdentifier() == 0 && 2781 !Param->isImplicit() && 2782 !getLangOptions().CPlusPlus) 2783 Diag(Param->getLocation(), diag::err_parameter_name_omitted); 2784 2785 // C99 6.7.5.3p12: 2786 // If the function declarator is not part of a definition of that 2787 // function, parameters may have incomplete type and may use the [*] 2788 // notation in their sequences of declarator specifiers to specify 2789 // variable length array types. 2790 QualType PType = Param->getOriginalType(); 2791 if (const ArrayType *AT = Context.getAsArrayType(PType)) { 2792 if (AT->getSizeModifier() == ArrayType::Star) { 2793 // FIXME: This diagnosic should point the the '[*]' if source-location 2794 // information is added for it. 2795 Diag(Param->getLocation(), diag::err_array_star_in_function_definition); 2796 } 2797 } 2798 } 2799 2800 return HasInvalidParm; 2801} 2802 2803/// CheckCastAlign - Implements -Wcast-align, which warns when a 2804/// pointer cast increases the alignment requirements. 2805void Sema::CheckCastAlign(Expr *Op, QualType T, SourceRange TRange) { 2806 // This is actually a lot of work to potentially be doing on every 2807 // cast; don't do it if we're ignoring -Wcast_align (as is the default). 2808 if (getDiagnostics().getDiagnosticLevel(diag::warn_cast_align) 2809 == Diagnostic::Ignored) 2810 return; 2811 2812 // Ignore dependent types. 2813 if (T->isDependentType() || Op->getType()->isDependentType()) 2814 return; 2815 2816 // Require that the destination be a pointer type. 2817 const PointerType *DestPtr = T->getAs<PointerType>(); 2818 if (!DestPtr) return; 2819 2820 // If the destination has alignment 1, we're done. 2821 QualType DestPointee = DestPtr->getPointeeType(); 2822 if (DestPointee->isIncompleteType()) return; 2823 CharUnits DestAlign = Context.getTypeAlignInChars(DestPointee); 2824 if (DestAlign.isOne()) return; 2825 2826 // Require that the source be a pointer type. 2827 const PointerType *SrcPtr = Op->getType()->getAs<PointerType>(); 2828 if (!SrcPtr) return; 2829 QualType SrcPointee = SrcPtr->getPointeeType(); 2830 2831 // Whitelist casts from cv void*. We already implicitly 2832 // whitelisted casts to cv void*, since they have alignment 1. 2833 // Also whitelist casts involving incomplete types, which implicitly 2834 // includes 'void'. 2835 if (SrcPointee->isIncompleteType()) return; 2836 2837 CharUnits SrcAlign = Context.getTypeAlignInChars(SrcPointee); 2838 if (SrcAlign >= DestAlign) return; 2839 2840 Diag(TRange.getBegin(), diag::warn_cast_align) 2841 << Op->getType() << T 2842 << static_cast<unsigned>(SrcAlign.getQuantity()) 2843 << static_cast<unsigned>(DestAlign.getQuantity()) 2844 << TRange << Op->getSourceRange(); 2845} 2846 2847