SemaChecking.cpp revision 4fe6441a558e471f2ad3c6bddf07c77332539f6b
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/SemaInternal.h" 17#include "clang/Sema/ScopeInfo.h" 18#include "clang/Analysis/Analyses/FormatString.h" 19#include "clang/AST/ASTContext.h" 20#include "clang/AST/CharUnits.h" 21#include "clang/AST/DeclCXX.h" 22#include "clang/AST/DeclObjC.h" 23#include "clang/AST/ExprCXX.h" 24#include "clang/AST/ExprObjC.h" 25#include "clang/AST/DeclObjC.h" 26#include "clang/AST/StmtCXX.h" 27#include "clang/AST/StmtObjC.h" 28#include "clang/Lex/LiteralSupport.h" 29#include "clang/Lex/Preprocessor.h" 30#include "llvm/ADT/BitVector.h" 31#include "llvm/ADT/STLExtras.h" 32#include "llvm/Support/raw_ostream.h" 33#include "clang/Basic/TargetBuiltins.h" 34#include "clang/Basic/TargetInfo.h" 35#include "clang/Basic/ConvertUTF.h" 36 37#include <limits> 38using namespace clang; 39using namespace sema; 40 41/// getLocationOfStringLiteralByte - Return a source location that points to the 42/// specified byte of the specified string literal. 43/// 44/// Strings are amazingly complex. They can be formed from multiple tokens and 45/// can have escape sequences in them in addition to the usual trigraph and 46/// escaped newline business. This routine handles this complexity. 47/// 48SourceLocation Sema::getLocationOfStringLiteralByte(const StringLiteral *SL, 49 unsigned ByteNo) const { 50 assert(!SL->isWide() && "This doesn't work for wide strings yet"); 51 52 // Loop over all of the tokens in this string until we find the one that 53 // contains the byte we're looking for. 54 unsigned TokNo = 0; 55 while (1) { 56 assert(TokNo < SL->getNumConcatenated() && "Invalid byte number!"); 57 SourceLocation StrTokLoc = SL->getStrTokenLoc(TokNo); 58 59 // Get the spelling of the string so that we can get the data that makes up 60 // the string literal, not the identifier for the macro it is potentially 61 // expanded through. 62 SourceLocation StrTokSpellingLoc = SourceMgr.getSpellingLoc(StrTokLoc); 63 64 // Re-lex the token to get its length and original spelling. 65 std::pair<FileID, unsigned> LocInfo = 66 SourceMgr.getDecomposedLoc(StrTokSpellingLoc); 67 bool Invalid = false; 68 llvm::StringRef Buffer = SourceMgr.getBufferData(LocInfo.first, &Invalid); 69 if (Invalid) 70 return StrTokSpellingLoc; 71 72 const char *StrData = Buffer.data()+LocInfo.second; 73 74 // Create a langops struct and enable trigraphs. This is sufficient for 75 // relexing tokens. 76 LangOptions LangOpts; 77 LangOpts.Trigraphs = true; 78 79 // Create a lexer starting at the beginning of this token. 80 Lexer TheLexer(StrTokSpellingLoc, LangOpts, Buffer.begin(), StrData, 81 Buffer.end()); 82 Token TheTok; 83 TheLexer.LexFromRawLexer(TheTok); 84 85 // Use the StringLiteralParser to compute the length of the string in bytes. 86 StringLiteralParser SLP(&TheTok, 1, PP, /*Complain=*/false); 87 unsigned TokNumBytes = SLP.GetStringLength(); 88 89 // If the byte is in this token, return the location of the byte. 90 if (ByteNo < TokNumBytes || 91 (ByteNo == TokNumBytes && TokNo == SL->getNumConcatenated())) { 92 unsigned Offset = 93 StringLiteralParser::getOffsetOfStringByte(TheTok, ByteNo, PP, 94 /*Complain=*/false); 95 96 // Now that we know the offset of the token in the spelling, use the 97 // preprocessor to get the offset in the original source. 98 return PP.AdvanceToTokenCharacter(StrTokLoc, Offset); 99 } 100 101 // Move to the next string token. 102 ++TokNo; 103 ByteNo -= TokNumBytes; 104 } 105} 106 107/// CheckablePrintfAttr - does a function call have a "printf" attribute 108/// and arguments that merit checking? 109bool Sema::CheckablePrintfAttr(const FormatAttr *Format, CallExpr *TheCall) { 110 if (Format->getType() == "printf") return true; 111 if (Format->getType() == "printf0") { 112 // printf0 allows null "format" string; if so don't check format/args 113 unsigned format_idx = Format->getFormatIdx() - 1; 114 // Does the index refer to the implicit object argument? 115 if (isa<CXXMemberCallExpr>(TheCall)) { 116 if (format_idx == 0) 117 return false; 118 --format_idx; 119 } 120 if (format_idx < TheCall->getNumArgs()) { 121 Expr *Format = TheCall->getArg(format_idx)->IgnoreParenCasts(); 122 if (!Format->isNullPointerConstant(Context, 123 Expr::NPC_ValueDependentIsNull)) 124 return true; 125 } 126 } 127 return false; 128} 129 130ExprResult 131Sema::CheckBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) { 132 ExprResult TheCallResult(Owned(TheCall)); 133 134 switch (BuiltinID) { 135 case Builtin::BI__builtin___CFStringMakeConstantString: 136 assert(TheCall->getNumArgs() == 1 && 137 "Wrong # arguments to builtin CFStringMakeConstantString"); 138 if (CheckObjCString(TheCall->getArg(0))) 139 return ExprError(); 140 break; 141 case Builtin::BI__builtin_stdarg_start: 142 case Builtin::BI__builtin_va_start: 143 if (SemaBuiltinVAStart(TheCall)) 144 return ExprError(); 145 break; 146 case Builtin::BI__builtin_isgreater: 147 case Builtin::BI__builtin_isgreaterequal: 148 case Builtin::BI__builtin_isless: 149 case Builtin::BI__builtin_islessequal: 150 case Builtin::BI__builtin_islessgreater: 151 case Builtin::BI__builtin_isunordered: 152 if (SemaBuiltinUnorderedCompare(TheCall)) 153 return ExprError(); 154 break; 155 case Builtin::BI__builtin_fpclassify: 156 if (SemaBuiltinFPClassification(TheCall, 6)) 157 return ExprError(); 158 break; 159 case Builtin::BI__builtin_isfinite: 160 case Builtin::BI__builtin_isinf: 161 case Builtin::BI__builtin_isinf_sign: 162 case Builtin::BI__builtin_isnan: 163 case Builtin::BI__builtin_isnormal: 164 if (SemaBuiltinFPClassification(TheCall, 1)) 165 return ExprError(); 166 break; 167 case Builtin::BI__builtin_return_address: 168 case Builtin::BI__builtin_frame_address: { 169 llvm::APSInt Result; 170 if (SemaBuiltinConstantArg(TheCall, 0, Result)) 171 return ExprError(); 172 break; 173 } 174 case Builtin::BI__builtin_eh_return_data_regno: { 175 llvm::APSInt Result; 176 if (SemaBuiltinConstantArg(TheCall, 0, Result)) 177 return ExprError(); 178 break; 179 } 180 case Builtin::BI__builtin_shufflevector: 181 return SemaBuiltinShuffleVector(TheCall); 182 // TheCall will be freed by the smart pointer here, but that's fine, since 183 // SemaBuiltinShuffleVector guts it, but then doesn't release it. 184 case Builtin::BI__builtin_prefetch: 185 if (SemaBuiltinPrefetch(TheCall)) 186 return ExprError(); 187 break; 188 case Builtin::BI__builtin_object_size: 189 if (SemaBuiltinObjectSize(TheCall)) 190 return ExprError(); 191 break; 192 case Builtin::BI__builtin_longjmp: 193 if (SemaBuiltinLongjmp(TheCall)) 194 return ExprError(); 195 break; 196 case Builtin::BI__sync_fetch_and_add: 197 case Builtin::BI__sync_fetch_and_sub: 198 case Builtin::BI__sync_fetch_and_or: 199 case Builtin::BI__sync_fetch_and_and: 200 case Builtin::BI__sync_fetch_and_xor: 201 case Builtin::BI__sync_add_and_fetch: 202 case Builtin::BI__sync_sub_and_fetch: 203 case Builtin::BI__sync_and_and_fetch: 204 case Builtin::BI__sync_or_and_fetch: 205 case Builtin::BI__sync_xor_and_fetch: 206 case Builtin::BI__sync_val_compare_and_swap: 207 case Builtin::BI__sync_bool_compare_and_swap: 208 case Builtin::BI__sync_lock_test_and_set: 209 case Builtin::BI__sync_lock_release: 210 return SemaBuiltinAtomicOverloaded(move(TheCallResult)); 211 } 212 213 // Since the target specific builtins for each arch overlap, only check those 214 // of the arch we are compiling for. 215 if (BuiltinID >= Builtin::FirstTSBuiltin) { 216 switch (Context.Target.getTriple().getArch()) { 217 case llvm::Triple::arm: 218 case llvm::Triple::thumb: 219 if (CheckARMBuiltinFunctionCall(BuiltinID, TheCall)) 220 return ExprError(); 221 break; 222 case llvm::Triple::x86: 223 case llvm::Triple::x86_64: 224 if (CheckX86BuiltinFunctionCall(BuiltinID, TheCall)) 225 return ExprError(); 226 break; 227 default: 228 break; 229 } 230 } 231 232 return move(TheCallResult); 233} 234 235bool Sema::CheckX86BuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) { 236 switch (BuiltinID) { 237 case X86::BI__builtin_ia32_palignr128: 238 case X86::BI__builtin_ia32_palignr: { 239 llvm::APSInt Result; 240 if (SemaBuiltinConstantArg(TheCall, 2, Result)) 241 return true; 242 break; 243 } 244 } 245 return false; 246} 247 248// Get the valid immediate range for the specified NEON type code. 249static unsigned RFT(unsigned t, bool shift = false) { 250 bool quad = t & 0x10; 251 252 switch (t & 0x7) { 253 case 0: // i8 254 return shift ? 7 : (8 << (int)quad) - 1; 255 case 1: // i16 256 return shift ? 15 : (4 << (int)quad) - 1; 257 case 2: // i32 258 return shift ? 31 : (2 << (int)quad) - 1; 259 case 3: // i64 260 return shift ? 63 : (1 << (int)quad) - 1; 261 case 4: // f32 262 assert(!shift && "cannot shift float types!"); 263 return (2 << (int)quad) - 1; 264 case 5: // poly8 265 assert(!shift && "cannot shift polynomial types!"); 266 return (8 << (int)quad) - 1; 267 case 6: // poly16 268 assert(!shift && "cannot shift polynomial types!"); 269 return (4 << (int)quad) - 1; 270 case 7: // float16 271 assert(!shift && "cannot shift float types!"); 272 return (4 << (int)quad) - 1; 273 } 274 return 0; 275} 276 277bool Sema::CheckARMBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) { 278 llvm::APSInt Result; 279 280 unsigned mask = 0; 281 unsigned TV = 0; 282 switch (BuiltinID) { 283#define GET_NEON_OVERLOAD_CHECK 284#include "clang/Basic/arm_neon.inc" 285#undef GET_NEON_OVERLOAD_CHECK 286 } 287 288 // For NEON intrinsics which are overloaded on vector element type, validate 289 // the immediate which specifies which variant to emit. 290 if (mask) { 291 unsigned ArgNo = TheCall->getNumArgs()-1; 292 if (SemaBuiltinConstantArg(TheCall, ArgNo, Result)) 293 return true; 294 295 TV = Result.getLimitedValue(32); 296 if ((TV > 31) || (mask & (1 << TV)) == 0) 297 return Diag(TheCall->getLocStart(), diag::err_invalid_neon_type_code) 298 << TheCall->getArg(ArgNo)->getSourceRange(); 299 } 300 301 // For NEON intrinsics which take an immediate value as part of the 302 // instruction, range check them here. 303 unsigned i = 0, l = 0, u = 0; 304 switch (BuiltinID) { 305 default: return false; 306 case ARM::BI__builtin_arm_ssat: i = 1; l = 1; u = 31; break; 307 case ARM::BI__builtin_arm_usat: i = 1; u = 31; break; 308 case ARM::BI__builtin_arm_vcvtr_f: 309 case ARM::BI__builtin_arm_vcvtr_d: i = 1; u = 1; break; 310#define GET_NEON_IMMEDIATE_CHECK 311#include "clang/Basic/arm_neon.inc" 312#undef GET_NEON_IMMEDIATE_CHECK 313 }; 314 315 // Check that the immediate argument is actually a constant. 316 if (SemaBuiltinConstantArg(TheCall, i, Result)) 317 return true; 318 319 // Range check against the upper/lower values for this isntruction. 320 unsigned Val = Result.getZExtValue(); 321 if (Val < l || Val > (u + l)) 322 return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range) 323 << l << u+l << TheCall->getArg(i)->getSourceRange(); 324 325 // FIXME: VFP Intrinsics should error if VFP not present. 326 return false; 327} 328 329/// CheckFunctionCall - Check a direct function call for various correctness 330/// and safety properties not strictly enforced by the C type system. 331bool Sema::CheckFunctionCall(FunctionDecl *FDecl, CallExpr *TheCall) { 332 // Get the IdentifierInfo* for the called function. 333 IdentifierInfo *FnInfo = FDecl->getIdentifier(); 334 335 // None of the checks below are needed for functions that don't have 336 // simple names (e.g., C++ conversion functions). 337 if (!FnInfo) 338 return false; 339 340 // FIXME: This mechanism should be abstracted to be less fragile and 341 // more efficient. For example, just map function ids to custom 342 // handlers. 343 344 // Printf checking. 345 if (const FormatAttr *Format = FDecl->getAttr<FormatAttr>()) { 346 const bool b = Format->getType() == "scanf"; 347 if (b || CheckablePrintfAttr(Format, TheCall)) { 348 bool HasVAListArg = Format->getFirstArg() == 0; 349 CheckPrintfScanfArguments(TheCall, HasVAListArg, 350 Format->getFormatIdx() - 1, 351 HasVAListArg ? 0 : Format->getFirstArg() - 1, 352 !b); 353 } 354 } 355 356 specific_attr_iterator<NonNullAttr> 357 i = FDecl->specific_attr_begin<NonNullAttr>(), 358 e = FDecl->specific_attr_end<NonNullAttr>(); 359 360 for (; i != e; ++i) 361 CheckNonNullArguments(*i, TheCall); 362 363 return false; 364} 365 366bool Sema::CheckBlockCall(NamedDecl *NDecl, CallExpr *TheCall) { 367 // Printf checking. 368 const FormatAttr *Format = NDecl->getAttr<FormatAttr>(); 369 if (!Format) 370 return false; 371 372 const VarDecl *V = dyn_cast<VarDecl>(NDecl); 373 if (!V) 374 return false; 375 376 QualType Ty = V->getType(); 377 if (!Ty->isBlockPointerType()) 378 return false; 379 380 const bool b = Format->getType() == "scanf"; 381 if (!b && !CheckablePrintfAttr(Format, TheCall)) 382 return false; 383 384 bool HasVAListArg = Format->getFirstArg() == 0; 385 CheckPrintfScanfArguments(TheCall, HasVAListArg, Format->getFormatIdx() - 1, 386 HasVAListArg ? 0 : Format->getFirstArg() - 1, !b); 387 388 return false; 389} 390 391/// SemaBuiltinAtomicOverloaded - We have a call to a function like 392/// __sync_fetch_and_add, which is an overloaded function based on the pointer 393/// type of its first argument. The main ActOnCallExpr routines have already 394/// promoted the types of arguments because all of these calls are prototyped as 395/// void(...). 396/// 397/// This function goes through and does final semantic checking for these 398/// builtins, 399ExprResult 400Sema::SemaBuiltinAtomicOverloaded(ExprResult TheCallResult) { 401 CallExpr *TheCall = (CallExpr *)TheCallResult.get(); 402 DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts()); 403 FunctionDecl *FDecl = cast<FunctionDecl>(DRE->getDecl()); 404 405 // Ensure that we have at least one argument to do type inference from. 406 if (TheCall->getNumArgs() < 1) { 407 Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args_at_least) 408 << 0 << 1 << TheCall->getNumArgs() 409 << TheCall->getCallee()->getSourceRange(); 410 return ExprError(); 411 } 412 413 // Inspect the first argument of the atomic builtin. This should always be 414 // a pointer type, whose element is an integral scalar or pointer type. 415 // Because it is a pointer type, we don't have to worry about any implicit 416 // casts here. 417 // FIXME: We don't allow floating point scalars as input. 418 Expr *FirstArg = TheCall->getArg(0); 419 if (!FirstArg->getType()->isPointerType()) { 420 Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer) 421 << FirstArg->getType() << FirstArg->getSourceRange(); 422 return ExprError(); 423 } 424 425 QualType ValType = 426 FirstArg->getType()->getAs<PointerType>()->getPointeeType(); 427 if (!ValType->isIntegerType() && !ValType->isPointerType() && 428 !ValType->isBlockPointerType()) { 429 Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer_intptr) 430 << FirstArg->getType() << FirstArg->getSourceRange(); 431 return ExprError(); 432 } 433 434 // The majority of builtins return a value, but a few have special return 435 // types, so allow them to override appropriately below. 436 QualType ResultType = ValType; 437 438 // We need to figure out which concrete builtin this maps onto. For example, 439 // __sync_fetch_and_add with a 2 byte object turns into 440 // __sync_fetch_and_add_2. 441#define BUILTIN_ROW(x) \ 442 { Builtin::BI##x##_1, Builtin::BI##x##_2, Builtin::BI##x##_4, \ 443 Builtin::BI##x##_8, Builtin::BI##x##_16 } 444 445 static const unsigned BuiltinIndices[][5] = { 446 BUILTIN_ROW(__sync_fetch_and_add), 447 BUILTIN_ROW(__sync_fetch_and_sub), 448 BUILTIN_ROW(__sync_fetch_and_or), 449 BUILTIN_ROW(__sync_fetch_and_and), 450 BUILTIN_ROW(__sync_fetch_and_xor), 451 452 BUILTIN_ROW(__sync_add_and_fetch), 453 BUILTIN_ROW(__sync_sub_and_fetch), 454 BUILTIN_ROW(__sync_and_and_fetch), 455 BUILTIN_ROW(__sync_or_and_fetch), 456 BUILTIN_ROW(__sync_xor_and_fetch), 457 458 BUILTIN_ROW(__sync_val_compare_and_swap), 459 BUILTIN_ROW(__sync_bool_compare_and_swap), 460 BUILTIN_ROW(__sync_lock_test_and_set), 461 BUILTIN_ROW(__sync_lock_release) 462 }; 463#undef BUILTIN_ROW 464 465 // Determine the index of the size. 466 unsigned SizeIndex; 467 switch (Context.getTypeSizeInChars(ValType).getQuantity()) { 468 case 1: SizeIndex = 0; break; 469 case 2: SizeIndex = 1; break; 470 case 4: SizeIndex = 2; break; 471 case 8: SizeIndex = 3; break; 472 case 16: SizeIndex = 4; break; 473 default: 474 Diag(DRE->getLocStart(), diag::err_atomic_builtin_pointer_size) 475 << FirstArg->getType() << FirstArg->getSourceRange(); 476 return ExprError(); 477 } 478 479 // Each of these builtins has one pointer argument, followed by some number of 480 // values (0, 1 or 2) followed by a potentially empty varags list of stuff 481 // that we ignore. Find out which row of BuiltinIndices to read from as well 482 // as the number of fixed args. 483 unsigned BuiltinID = FDecl->getBuiltinID(); 484 unsigned BuiltinIndex, NumFixed = 1; 485 switch (BuiltinID) { 486 default: assert(0 && "Unknown overloaded atomic builtin!"); 487 case Builtin::BI__sync_fetch_and_add: BuiltinIndex = 0; break; 488 case Builtin::BI__sync_fetch_and_sub: BuiltinIndex = 1; break; 489 case Builtin::BI__sync_fetch_and_or: BuiltinIndex = 2; break; 490 case Builtin::BI__sync_fetch_and_and: BuiltinIndex = 3; break; 491 case Builtin::BI__sync_fetch_and_xor: BuiltinIndex = 4; break; 492 493 case Builtin::BI__sync_add_and_fetch: BuiltinIndex = 5; break; 494 case Builtin::BI__sync_sub_and_fetch: BuiltinIndex = 6; break; 495 case Builtin::BI__sync_and_and_fetch: BuiltinIndex = 7; break; 496 case Builtin::BI__sync_or_and_fetch: BuiltinIndex = 8; break; 497 case Builtin::BI__sync_xor_and_fetch: BuiltinIndex = 9; break; 498 499 case Builtin::BI__sync_val_compare_and_swap: 500 BuiltinIndex = 10; 501 NumFixed = 2; 502 break; 503 case Builtin::BI__sync_bool_compare_and_swap: 504 BuiltinIndex = 11; 505 NumFixed = 2; 506 ResultType = Context.BoolTy; 507 break; 508 case Builtin::BI__sync_lock_test_and_set: BuiltinIndex = 12; break; 509 case Builtin::BI__sync_lock_release: 510 BuiltinIndex = 13; 511 NumFixed = 0; 512 ResultType = Context.VoidTy; 513 break; 514 } 515 516 // Now that we know how many fixed arguments we expect, first check that we 517 // have at least that many. 518 if (TheCall->getNumArgs() < 1+NumFixed) { 519 Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args_at_least) 520 << 0 << 1+NumFixed << TheCall->getNumArgs() 521 << TheCall->getCallee()->getSourceRange(); 522 return ExprError(); 523 } 524 525 // Get the decl for the concrete builtin from this, we can tell what the 526 // concrete integer type we should convert to is. 527 unsigned NewBuiltinID = BuiltinIndices[BuiltinIndex][SizeIndex]; 528 const char *NewBuiltinName = Context.BuiltinInfo.GetName(NewBuiltinID); 529 IdentifierInfo *NewBuiltinII = PP.getIdentifierInfo(NewBuiltinName); 530 FunctionDecl *NewBuiltinDecl = 531 cast<FunctionDecl>(LazilyCreateBuiltin(NewBuiltinII, NewBuiltinID, 532 TUScope, false, DRE->getLocStart())); 533 534 // The first argument --- the pointer --- has a fixed type; we 535 // deduce the types of the rest of the arguments accordingly. Walk 536 // the remaining arguments, converting them to the deduced value type. 537 for (unsigned i = 0; i != NumFixed; ++i) { 538 Expr *Arg = TheCall->getArg(i+1); 539 540 // If the argument is an implicit cast, then there was a promotion due to 541 // "...", just remove it now. 542 if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(Arg)) { 543 Arg = ICE->getSubExpr(); 544 ICE->setSubExpr(0); 545 TheCall->setArg(i+1, Arg); 546 } 547 548 // GCC does an implicit conversion to the pointer or integer ValType. This 549 // can fail in some cases (1i -> int**), check for this error case now. 550 CastKind Kind = CK_Unknown; 551 CXXCastPath BasePath; 552 if (CheckCastTypes(Arg->getSourceRange(), ValType, Arg, Kind, BasePath)) 553 return ExprError(); 554 555 // Okay, we have something that *can* be converted to the right type. Check 556 // to see if there is a potentially weird extension going on here. This can 557 // happen when you do an atomic operation on something like an char* and 558 // pass in 42. The 42 gets converted to char. This is even more strange 559 // for things like 45.123 -> char, etc. 560 // FIXME: Do this check. 561 ImpCastExprToType(Arg, ValType, Kind, VK_RValue, &BasePath); 562 TheCall->setArg(i+1, Arg); 563 } 564 565 // Switch the DeclRefExpr to refer to the new decl. 566 DRE->setDecl(NewBuiltinDecl); 567 DRE->setType(NewBuiltinDecl->getType()); 568 569 // Set the callee in the CallExpr. 570 // FIXME: This leaks the original parens and implicit casts. 571 Expr *PromotedCall = DRE; 572 UsualUnaryConversions(PromotedCall); 573 TheCall->setCallee(PromotedCall); 574 575 // Change the result type of the call to match the original value type. This 576 // is arbitrary, but the codegen for these builtins ins design to handle it 577 // gracefully. 578 TheCall->setType(ResultType); 579 580 return move(TheCallResult); 581} 582 583 584/// CheckObjCString - Checks that the argument to the builtin 585/// CFString constructor is correct 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 if (Literal->containsNonAsciiOrNull()) { 605 llvm::StringRef String = Literal->getString(); 606 unsigned NumBytes = String.size(); 607 llvm::SmallVector<UTF16, 128> ToBuf(NumBytes); 608 const UTF8 *FromPtr = (UTF8 *)String.data(); 609 UTF16 *ToPtr = &ToBuf[0]; 610 611 ConversionResult Result = ConvertUTF8toUTF16(&FromPtr, FromPtr + NumBytes, 612 &ToPtr, ToPtr + NumBytes, 613 strictConversion); 614 // Check for conversion failure. 615 if (Result != conversionOK) 616 Diag(Arg->getLocStart(), 617 diag::warn_cfstring_truncated) << Arg->getSourceRange(); 618 } 619 return false; 620} 621 622/// SemaBuiltinVAStart - Check the arguments to __builtin_va_start for validity. 623/// Emit an error and return true on failure, return false on success. 624bool Sema::SemaBuiltinVAStart(CallExpr *TheCall) { 625 Expr *Fn = TheCall->getCallee(); 626 if (TheCall->getNumArgs() > 2) { 627 Diag(TheCall->getArg(2)->getLocStart(), 628 diag::err_typecheck_call_too_many_args) 629 << 0 /*function call*/ << 2 << TheCall->getNumArgs() 630 << Fn->getSourceRange() 631 << SourceRange(TheCall->getArg(2)->getLocStart(), 632 (*(TheCall->arg_end()-1))->getLocEnd()); 633 return true; 634 } 635 636 if (TheCall->getNumArgs() < 2) { 637 return Diag(TheCall->getLocEnd(), 638 diag::err_typecheck_call_too_few_args_at_least) 639 << 0 /*function call*/ << 2 << TheCall->getNumArgs(); 640 } 641 642 // Determine whether the current function is variadic or not. 643 BlockScopeInfo *CurBlock = getCurBlock(); 644 bool isVariadic; 645 if (CurBlock) 646 isVariadic = CurBlock->TheDecl->isVariadic(); 647 else if (FunctionDecl *FD = getCurFunctionDecl()) 648 isVariadic = FD->isVariadic(); 649 else 650 isVariadic = getCurMethodDecl()->isVariadic(); 651 652 if (!isVariadic) { 653 Diag(Fn->getLocStart(), diag::err_va_start_used_in_non_variadic_function); 654 return true; 655 } 656 657 // Verify that the second argument to the builtin is the last argument of the 658 // current function or method. 659 bool SecondArgIsLastNamedArgument = false; 660 const Expr *Arg = TheCall->getArg(1)->IgnoreParenCasts(); 661 662 if (const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(Arg)) { 663 if (const ParmVarDecl *PV = dyn_cast<ParmVarDecl>(DR->getDecl())) { 664 // FIXME: This isn't correct for methods (results in bogus warning). 665 // Get the last formal in the current function. 666 const ParmVarDecl *LastArg; 667 if (CurBlock) 668 LastArg = *(CurBlock->TheDecl->param_end()-1); 669 else if (FunctionDecl *FD = getCurFunctionDecl()) 670 LastArg = *(FD->param_end()-1); 671 else 672 LastArg = *(getCurMethodDecl()->param_end()-1); 673 SecondArgIsLastNamedArgument = PV == LastArg; 674 } 675 } 676 677 if (!SecondArgIsLastNamedArgument) 678 Diag(TheCall->getArg(1)->getLocStart(), 679 diag::warn_second_parameter_of_va_start_not_last_named_argument); 680 return false; 681} 682 683/// SemaBuiltinUnorderedCompare - Handle functions like __builtin_isgreater and 684/// friends. This is declared to take (...), so we have to check everything. 685bool Sema::SemaBuiltinUnorderedCompare(CallExpr *TheCall) { 686 if (TheCall->getNumArgs() < 2) 687 return Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args) 688 << 0 << 2 << TheCall->getNumArgs()/*function call*/; 689 if (TheCall->getNumArgs() > 2) 690 return Diag(TheCall->getArg(2)->getLocStart(), 691 diag::err_typecheck_call_too_many_args) 692 << 0 /*function call*/ << 2 << TheCall->getNumArgs() 693 << SourceRange(TheCall->getArg(2)->getLocStart(), 694 (*(TheCall->arg_end()-1))->getLocEnd()); 695 696 Expr *OrigArg0 = TheCall->getArg(0); 697 Expr *OrigArg1 = TheCall->getArg(1); 698 699 // Do standard promotions between the two arguments, returning their common 700 // type. 701 QualType Res = UsualArithmeticConversions(OrigArg0, OrigArg1, false); 702 703 // Make sure any conversions are pushed back into the call; this is 704 // type safe since unordered compare builtins are declared as "_Bool 705 // foo(...)". 706 TheCall->setArg(0, OrigArg0); 707 TheCall->setArg(1, OrigArg1); 708 709 if (OrigArg0->isTypeDependent() || OrigArg1->isTypeDependent()) 710 return false; 711 712 // If the common type isn't a real floating type, then the arguments were 713 // invalid for this operation. 714 if (!Res->isRealFloatingType()) 715 return Diag(OrigArg0->getLocStart(), 716 diag::err_typecheck_call_invalid_ordered_compare) 717 << OrigArg0->getType() << OrigArg1->getType() 718 << SourceRange(OrigArg0->getLocStart(), OrigArg1->getLocEnd()); 719 720 return false; 721} 722 723/// SemaBuiltinSemaBuiltinFPClassification - Handle functions like 724/// __builtin_isnan and friends. This is declared to take (...), so we have 725/// to check everything. We expect the last argument to be a floating point 726/// value. 727bool Sema::SemaBuiltinFPClassification(CallExpr *TheCall, unsigned NumArgs) { 728 if (TheCall->getNumArgs() < NumArgs) 729 return Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args) 730 << 0 << NumArgs << TheCall->getNumArgs()/*function call*/; 731 if (TheCall->getNumArgs() > NumArgs) 732 return Diag(TheCall->getArg(NumArgs)->getLocStart(), 733 diag::err_typecheck_call_too_many_args) 734 << 0 /*function call*/ << NumArgs << TheCall->getNumArgs() 735 << SourceRange(TheCall->getArg(NumArgs)->getLocStart(), 736 (*(TheCall->arg_end()-1))->getLocEnd()); 737 738 Expr *OrigArg = TheCall->getArg(NumArgs-1); 739 740 if (OrigArg->isTypeDependent()) 741 return false; 742 743 // This operation requires a non-_Complex floating-point number. 744 if (!OrigArg->getType()->isRealFloatingType()) 745 return Diag(OrigArg->getLocStart(), 746 diag::err_typecheck_call_invalid_unary_fp) 747 << OrigArg->getType() << OrigArg->getSourceRange(); 748 749 // If this is an implicit conversion from float -> double, remove it. 750 if (ImplicitCastExpr *Cast = dyn_cast<ImplicitCastExpr>(OrigArg)) { 751 Expr *CastArg = Cast->getSubExpr(); 752 if (CastArg->getType()->isSpecificBuiltinType(BuiltinType::Float)) { 753 assert(Cast->getType()->isSpecificBuiltinType(BuiltinType::Double) && 754 "promotion from float to double is the only expected cast here"); 755 Cast->setSubExpr(0); 756 TheCall->setArg(NumArgs-1, CastArg); 757 OrigArg = CastArg; 758 } 759 } 760 761 return false; 762} 763 764/// SemaBuiltinShuffleVector - Handle __builtin_shufflevector. 765// This is declared to take (...), so we have to check everything. 766ExprResult Sema::SemaBuiltinShuffleVector(CallExpr *TheCall) { 767 if (TheCall->getNumArgs() < 2) 768 return ExprError(Diag(TheCall->getLocEnd(), 769 diag::err_typecheck_call_too_few_args_at_least) 770 << 0 /*function call*/ << 2 << TheCall->getNumArgs() 771 << TheCall->getSourceRange()); 772 773 // Determine which of the following types of shufflevector we're checking: 774 // 1) unary, vector mask: (lhs, mask) 775 // 2) binary, vector mask: (lhs, rhs, mask) 776 // 3) binary, scalar mask: (lhs, rhs, index, ..., index) 777 QualType resType = TheCall->getArg(0)->getType(); 778 unsigned numElements = 0; 779 780 if (!TheCall->getArg(0)->isTypeDependent() && 781 !TheCall->getArg(1)->isTypeDependent()) { 782 QualType LHSType = TheCall->getArg(0)->getType(); 783 QualType RHSType = TheCall->getArg(1)->getType(); 784 785 if (!LHSType->isVectorType() || !RHSType->isVectorType()) { 786 Diag(TheCall->getLocStart(), diag::err_shufflevector_non_vector) 787 << SourceRange(TheCall->getArg(0)->getLocStart(), 788 TheCall->getArg(1)->getLocEnd()); 789 return ExprError(); 790 } 791 792 numElements = LHSType->getAs<VectorType>()->getNumElements(); 793 unsigned numResElements = TheCall->getNumArgs() - 2; 794 795 // Check to see if we have a call with 2 vector arguments, the unary shuffle 796 // with mask. If so, verify that RHS is an integer vector type with the 797 // same number of elts as lhs. 798 if (TheCall->getNumArgs() == 2) { 799 if (!RHSType->hasIntegerRepresentation() || 800 RHSType->getAs<VectorType>()->getNumElements() != numElements) 801 Diag(TheCall->getLocStart(), diag::err_shufflevector_incompatible_vector) 802 << SourceRange(TheCall->getArg(1)->getLocStart(), 803 TheCall->getArg(1)->getLocEnd()); 804 numResElements = numElements; 805 } 806 else if (!Context.hasSameUnqualifiedType(LHSType, RHSType)) { 807 Diag(TheCall->getLocStart(), diag::err_shufflevector_incompatible_vector) 808 << SourceRange(TheCall->getArg(0)->getLocStart(), 809 TheCall->getArg(1)->getLocEnd()); 810 return ExprError(); 811 } else if (numElements != numResElements) { 812 QualType eltType = LHSType->getAs<VectorType>()->getElementType(); 813 resType = Context.getVectorType(eltType, numResElements, 814 VectorType::NotAltiVec); 815 } 816 } 817 818 for (unsigned i = 2; i < TheCall->getNumArgs(); i++) { 819 if (TheCall->getArg(i)->isTypeDependent() || 820 TheCall->getArg(i)->isValueDependent()) 821 continue; 822 823 llvm::APSInt Result(32); 824 if (!TheCall->getArg(i)->isIntegerConstantExpr(Result, Context)) 825 return ExprError(Diag(TheCall->getLocStart(), 826 diag::err_shufflevector_nonconstant_argument) 827 << TheCall->getArg(i)->getSourceRange()); 828 829 if (Result.getActiveBits() > 64 || Result.getZExtValue() >= numElements*2) 830 return ExprError(Diag(TheCall->getLocStart(), 831 diag::err_shufflevector_argument_too_large) 832 << TheCall->getArg(i)->getSourceRange()); 833 } 834 835 llvm::SmallVector<Expr*, 32> exprs; 836 837 for (unsigned i = 0, e = TheCall->getNumArgs(); i != e; i++) { 838 exprs.push_back(TheCall->getArg(i)); 839 TheCall->setArg(i, 0); 840 } 841 842 return Owned(new (Context) ShuffleVectorExpr(Context, exprs.begin(), 843 exprs.size(), resType, 844 TheCall->getCallee()->getLocStart(), 845 TheCall->getRParenLoc())); 846} 847 848/// SemaBuiltinPrefetch - Handle __builtin_prefetch. 849// This is declared to take (const void*, ...) and can take two 850// optional constant int args. 851bool Sema::SemaBuiltinPrefetch(CallExpr *TheCall) { 852 unsigned NumArgs = TheCall->getNumArgs(); 853 854 if (NumArgs > 3) 855 return Diag(TheCall->getLocEnd(), 856 diag::err_typecheck_call_too_many_args_at_most) 857 << 0 /*function call*/ << 3 << NumArgs 858 << TheCall->getSourceRange(); 859 860 // Argument 0 is checked for us and the remaining arguments must be 861 // constant integers. 862 for (unsigned i = 1; i != NumArgs; ++i) { 863 Expr *Arg = TheCall->getArg(i); 864 865 llvm::APSInt Result; 866 if (SemaBuiltinConstantArg(TheCall, i, Result)) 867 return true; 868 869 // FIXME: gcc issues a warning and rewrites these to 0. These 870 // seems especially odd for the third argument since the default 871 // is 3. 872 if (i == 1) { 873 if (Result.getLimitedValue() > 1) 874 return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range) 875 << "0" << "1" << Arg->getSourceRange(); 876 } else { 877 if (Result.getLimitedValue() > 3) 878 return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range) 879 << "0" << "3" << Arg->getSourceRange(); 880 } 881 } 882 883 return false; 884} 885 886/// SemaBuiltinConstantArg - Handle a check if argument ArgNum of CallExpr 887/// TheCall is a constant expression. 888bool Sema::SemaBuiltinConstantArg(CallExpr *TheCall, int ArgNum, 889 llvm::APSInt &Result) { 890 Expr *Arg = TheCall->getArg(ArgNum); 891 DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts()); 892 FunctionDecl *FDecl = cast<FunctionDecl>(DRE->getDecl()); 893 894 if (Arg->isTypeDependent() || Arg->isValueDependent()) return false; 895 896 if (!Arg->isIntegerConstantExpr(Result, Context)) 897 return Diag(TheCall->getLocStart(), diag::err_constant_integer_arg_type) 898 << FDecl->getDeclName() << Arg->getSourceRange(); 899 900 return false; 901} 902 903/// SemaBuiltinObjectSize - Handle __builtin_object_size(void *ptr, 904/// int type). This simply type checks that type is one of the defined 905/// constants (0-3). 906// For compatability check 0-3, llvm only handles 0 and 2. 907bool Sema::SemaBuiltinObjectSize(CallExpr *TheCall) { 908 llvm::APSInt Result; 909 910 // Check constant-ness first. 911 if (SemaBuiltinConstantArg(TheCall, 1, Result)) 912 return true; 913 914 Expr *Arg = TheCall->getArg(1); 915 if (Result.getSExtValue() < 0 || Result.getSExtValue() > 3) { 916 return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range) 917 << "0" << "3" << SourceRange(Arg->getLocStart(), Arg->getLocEnd()); 918 } 919 920 return false; 921} 922 923/// SemaBuiltinLongjmp - Handle __builtin_longjmp(void *env[5], int val). 924/// This checks that val is a constant 1. 925bool Sema::SemaBuiltinLongjmp(CallExpr *TheCall) { 926 Expr *Arg = TheCall->getArg(1); 927 llvm::APSInt Result; 928 929 // TODO: This is less than ideal. Overload this to take a value. 930 if (SemaBuiltinConstantArg(TheCall, 1, Result)) 931 return true; 932 933 if (Result != 1) 934 return Diag(TheCall->getLocStart(), diag::err_builtin_longjmp_invalid_val) 935 << SourceRange(Arg->getLocStart(), Arg->getLocEnd()); 936 937 return false; 938} 939 940// Handle i > 1 ? "x" : "y", recursivelly 941bool Sema::SemaCheckStringLiteral(const Expr *E, const CallExpr *TheCall, 942 bool HasVAListArg, 943 unsigned format_idx, unsigned firstDataArg, 944 bool isPrintf) { 945 tryAgain: 946 if (E->isTypeDependent() || E->isValueDependent()) 947 return false; 948 949 switch (E->getStmtClass()) { 950 case Stmt::ConditionalOperatorClass: { 951 const ConditionalOperator *C = cast<ConditionalOperator>(E); 952 return SemaCheckStringLiteral(C->getTrueExpr(), TheCall, HasVAListArg, 953 format_idx, firstDataArg, isPrintf) 954 && SemaCheckStringLiteral(C->getRHS(), TheCall, HasVAListArg, 955 format_idx, firstDataArg, isPrintf); 956 } 957 958 case Stmt::ImplicitCastExprClass: { 959 E = cast<ImplicitCastExpr>(E)->getSubExpr(); 960 goto tryAgain; 961 } 962 963 case Stmt::ParenExprClass: { 964 E = cast<ParenExpr>(E)->getSubExpr(); 965 goto tryAgain; 966 } 967 968 case Stmt::DeclRefExprClass: { 969 const DeclRefExpr *DR = cast<DeclRefExpr>(E); 970 971 // As an exception, do not flag errors for variables binding to 972 // const string literals. 973 if (const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl())) { 974 bool isConstant = false; 975 QualType T = DR->getType(); 976 977 if (const ArrayType *AT = Context.getAsArrayType(T)) { 978 isConstant = AT->getElementType().isConstant(Context); 979 } else if (const PointerType *PT = T->getAs<PointerType>()) { 980 isConstant = T.isConstant(Context) && 981 PT->getPointeeType().isConstant(Context); 982 } 983 984 if (isConstant) { 985 if (const Expr *Init = VD->getAnyInitializer()) 986 return SemaCheckStringLiteral(Init, TheCall, 987 HasVAListArg, format_idx, firstDataArg, 988 isPrintf); 989 } 990 991 // For vprintf* functions (i.e., HasVAListArg==true), we add a 992 // special check to see if the format string is a function parameter 993 // of the function calling the printf function. If the function 994 // has an attribute indicating it is a printf-like function, then we 995 // should suppress warnings concerning non-literals being used in a call 996 // to a vprintf function. For example: 997 // 998 // void 999 // logmessage(char const *fmt __attribute__ (format (printf, 1, 2)), ...){ 1000 // va_list ap; 1001 // va_start(ap, fmt); 1002 // vprintf(fmt, ap); // Do NOT emit a warning about "fmt". 1003 // ... 1004 // 1005 // 1006 // FIXME: We don't have full attribute support yet, so just check to see 1007 // if the argument is a DeclRefExpr that references a parameter. We'll 1008 // add proper support for checking the attribute later. 1009 if (HasVAListArg) 1010 if (isa<ParmVarDecl>(VD)) 1011 return true; 1012 } 1013 1014 return false; 1015 } 1016 1017 case Stmt::CallExprClass: { 1018 const CallExpr *CE = cast<CallExpr>(E); 1019 if (const ImplicitCastExpr *ICE 1020 = dyn_cast<ImplicitCastExpr>(CE->getCallee())) { 1021 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(ICE->getSubExpr())) { 1022 if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(DRE->getDecl())) { 1023 if (const FormatArgAttr *FA = FD->getAttr<FormatArgAttr>()) { 1024 unsigned ArgIndex = FA->getFormatIdx(); 1025 const Expr *Arg = CE->getArg(ArgIndex - 1); 1026 1027 return SemaCheckStringLiteral(Arg, TheCall, HasVAListArg, 1028 format_idx, firstDataArg, isPrintf); 1029 } 1030 } 1031 } 1032 } 1033 1034 return false; 1035 } 1036 case Stmt::ObjCStringLiteralClass: 1037 case Stmt::StringLiteralClass: { 1038 const StringLiteral *StrE = NULL; 1039 1040 if (const ObjCStringLiteral *ObjCFExpr = dyn_cast<ObjCStringLiteral>(E)) 1041 StrE = ObjCFExpr->getString(); 1042 else 1043 StrE = cast<StringLiteral>(E); 1044 1045 if (StrE) { 1046 CheckFormatString(StrE, E, TheCall, HasVAListArg, format_idx, 1047 firstDataArg, isPrintf); 1048 return true; 1049 } 1050 1051 return false; 1052 } 1053 1054 default: 1055 return false; 1056 } 1057} 1058 1059void 1060Sema::CheckNonNullArguments(const NonNullAttr *NonNull, 1061 const CallExpr *TheCall) { 1062 for (NonNullAttr::args_iterator i = NonNull->args_begin(), 1063 e = NonNull->args_end(); 1064 i != e; ++i) { 1065 const Expr *ArgExpr = TheCall->getArg(*i); 1066 if (ArgExpr->isNullPointerConstant(Context, 1067 Expr::NPC_ValueDependentIsNotNull)) 1068 Diag(TheCall->getCallee()->getLocStart(), diag::warn_null_arg) 1069 << ArgExpr->getSourceRange(); 1070 } 1071} 1072 1073/// CheckPrintfScanfArguments - Check calls to printf and scanf (and similar 1074/// functions) for correct use of format strings. 1075void 1076Sema::CheckPrintfScanfArguments(const CallExpr *TheCall, bool HasVAListArg, 1077 unsigned format_idx, unsigned firstDataArg, 1078 bool isPrintf) { 1079 1080 const Expr *Fn = TheCall->getCallee(); 1081 1082 // The way the format attribute works in GCC, the implicit this argument 1083 // of member functions is counted. However, it doesn't appear in our own 1084 // lists, so decrement format_idx in that case. 1085 if (isa<CXXMemberCallExpr>(TheCall)) { 1086 // Catch a format attribute mistakenly referring to the object argument. 1087 if (format_idx == 0) 1088 return; 1089 --format_idx; 1090 if(firstDataArg != 0) 1091 --firstDataArg; 1092 } 1093 1094 // CHECK: printf/scanf-like function is called with no format string. 1095 if (format_idx >= TheCall->getNumArgs()) { 1096 Diag(TheCall->getRParenLoc(), diag::warn_missing_format_string) 1097 << Fn->getSourceRange(); 1098 return; 1099 } 1100 1101 const Expr *OrigFormatExpr = TheCall->getArg(format_idx)->IgnoreParenCasts(); 1102 1103 // CHECK: format string is not a string literal. 1104 // 1105 // Dynamically generated format strings are difficult to 1106 // automatically vet at compile time. Requiring that format strings 1107 // are string literals: (1) permits the checking of format strings by 1108 // the compiler and thereby (2) can practically remove the source of 1109 // many format string exploits. 1110 1111 // Format string can be either ObjC string (e.g. @"%d") or 1112 // C string (e.g. "%d") 1113 // ObjC string uses the same format specifiers as C string, so we can use 1114 // the same format string checking logic for both ObjC and C strings. 1115 if (SemaCheckStringLiteral(OrigFormatExpr, TheCall, HasVAListArg, format_idx, 1116 firstDataArg, isPrintf)) 1117 return; // Literal format string found, check done! 1118 1119 // If there are no arguments specified, warn with -Wformat-security, otherwise 1120 // warn only with -Wformat-nonliteral. 1121 if (TheCall->getNumArgs() == format_idx+1) 1122 Diag(TheCall->getArg(format_idx)->getLocStart(), 1123 diag::warn_format_nonliteral_noargs) 1124 << OrigFormatExpr->getSourceRange(); 1125 else 1126 Diag(TheCall->getArg(format_idx)->getLocStart(), 1127 diag::warn_format_nonliteral) 1128 << OrigFormatExpr->getSourceRange(); 1129} 1130 1131namespace { 1132class CheckFormatHandler : public analyze_format_string::FormatStringHandler { 1133protected: 1134 Sema &S; 1135 const StringLiteral *FExpr; 1136 const Expr *OrigFormatExpr; 1137 const unsigned FirstDataArg; 1138 const unsigned NumDataArgs; 1139 const bool IsObjCLiteral; 1140 const char *Beg; // Start of format string. 1141 const bool HasVAListArg; 1142 const CallExpr *TheCall; 1143 unsigned FormatIdx; 1144 llvm::BitVector CoveredArgs; 1145 bool usesPositionalArgs; 1146 bool atFirstArg; 1147public: 1148 CheckFormatHandler(Sema &s, const StringLiteral *fexpr, 1149 const Expr *origFormatExpr, unsigned firstDataArg, 1150 unsigned numDataArgs, bool isObjCLiteral, 1151 const char *beg, bool hasVAListArg, 1152 const CallExpr *theCall, unsigned formatIdx) 1153 : S(s), FExpr(fexpr), OrigFormatExpr(origFormatExpr), 1154 FirstDataArg(firstDataArg), 1155 NumDataArgs(numDataArgs), 1156 IsObjCLiteral(isObjCLiteral), Beg(beg), 1157 HasVAListArg(hasVAListArg), 1158 TheCall(theCall), FormatIdx(formatIdx), 1159 usesPositionalArgs(false), atFirstArg(true) { 1160 CoveredArgs.resize(numDataArgs); 1161 CoveredArgs.reset(); 1162 } 1163 1164 void DoneProcessing(); 1165 1166 void HandleIncompleteSpecifier(const char *startSpecifier, 1167 unsigned specifierLen); 1168 1169 virtual void HandleInvalidPosition(const char *startSpecifier, 1170 unsigned specifierLen, 1171 analyze_format_string::PositionContext p); 1172 1173 virtual void HandleZeroPosition(const char *startPos, unsigned posLen); 1174 1175 void HandleNullChar(const char *nullCharacter); 1176 1177protected: 1178 bool HandleInvalidConversionSpecifier(unsigned argIndex, SourceLocation Loc, 1179 const char *startSpec, 1180 unsigned specifierLen, 1181 const char *csStart, unsigned csLen); 1182 1183 SourceRange getFormatStringRange(); 1184 CharSourceRange getSpecifierRange(const char *startSpecifier, 1185 unsigned specifierLen); 1186 SourceLocation getLocationOfByte(const char *x); 1187 1188 const Expr *getDataArg(unsigned i) const; 1189 1190 bool CheckNumArgs(const analyze_format_string::FormatSpecifier &FS, 1191 const analyze_format_string::ConversionSpecifier &CS, 1192 const char *startSpecifier, unsigned specifierLen, 1193 unsigned argIndex); 1194}; 1195} 1196 1197SourceRange CheckFormatHandler::getFormatStringRange() { 1198 return OrigFormatExpr->getSourceRange(); 1199} 1200 1201CharSourceRange CheckFormatHandler:: 1202getSpecifierRange(const char *startSpecifier, unsigned specifierLen) { 1203 SourceLocation Start = getLocationOfByte(startSpecifier); 1204 SourceLocation End = getLocationOfByte(startSpecifier + specifierLen - 1); 1205 1206 // Advance the end SourceLocation by one due to half-open ranges. 1207 End = End.getFileLocWithOffset(1); 1208 1209 return CharSourceRange::getCharRange(Start, End); 1210} 1211 1212SourceLocation CheckFormatHandler::getLocationOfByte(const char *x) { 1213 return S.getLocationOfStringLiteralByte(FExpr, x - Beg); 1214} 1215 1216void CheckFormatHandler::HandleIncompleteSpecifier(const char *startSpecifier, 1217 unsigned specifierLen){ 1218 SourceLocation Loc = getLocationOfByte(startSpecifier); 1219 S.Diag(Loc, diag::warn_printf_incomplete_specifier) 1220 << getSpecifierRange(startSpecifier, specifierLen); 1221} 1222 1223void 1224CheckFormatHandler::HandleInvalidPosition(const char *startPos, unsigned posLen, 1225 analyze_format_string::PositionContext p) { 1226 SourceLocation Loc = getLocationOfByte(startPos); 1227 S.Diag(Loc, diag::warn_format_invalid_positional_specifier) 1228 << (unsigned) p << getSpecifierRange(startPos, posLen); 1229} 1230 1231void CheckFormatHandler::HandleZeroPosition(const char *startPos, 1232 unsigned posLen) { 1233 SourceLocation Loc = getLocationOfByte(startPos); 1234 S.Diag(Loc, diag::warn_format_zero_positional_specifier) 1235 << getSpecifierRange(startPos, posLen); 1236} 1237 1238void CheckFormatHandler::HandleNullChar(const char *nullCharacter) { 1239 // The presence of a null character is likely an error. 1240 S.Diag(getLocationOfByte(nullCharacter), 1241 diag::warn_printf_format_string_contains_null_char) 1242 << getFormatStringRange(); 1243} 1244 1245const Expr *CheckFormatHandler::getDataArg(unsigned i) const { 1246 return TheCall->getArg(FirstDataArg + i); 1247} 1248 1249void CheckFormatHandler::DoneProcessing() { 1250 // Does the number of data arguments exceed the number of 1251 // format conversions in the format string? 1252 if (!HasVAListArg) { 1253 // Find any arguments that weren't covered. 1254 CoveredArgs.flip(); 1255 signed notCoveredArg = CoveredArgs.find_first(); 1256 if (notCoveredArg >= 0) { 1257 assert((unsigned)notCoveredArg < NumDataArgs); 1258 S.Diag(getDataArg((unsigned) notCoveredArg)->getLocStart(), 1259 diag::warn_printf_data_arg_not_used) 1260 << getFormatStringRange(); 1261 } 1262 } 1263} 1264 1265bool 1266CheckFormatHandler::HandleInvalidConversionSpecifier(unsigned argIndex, 1267 SourceLocation Loc, 1268 const char *startSpec, 1269 unsigned specifierLen, 1270 const char *csStart, 1271 unsigned csLen) { 1272 1273 bool keepGoing = true; 1274 if (argIndex < NumDataArgs) { 1275 // Consider the argument coverered, even though the specifier doesn't 1276 // make sense. 1277 CoveredArgs.set(argIndex); 1278 } 1279 else { 1280 // If argIndex exceeds the number of data arguments we 1281 // don't issue a warning because that is just a cascade of warnings (and 1282 // they may have intended '%%' anyway). We don't want to continue processing 1283 // the format string after this point, however, as we will like just get 1284 // gibberish when trying to match arguments. 1285 keepGoing = false; 1286 } 1287 1288 S.Diag(Loc, diag::warn_format_invalid_conversion) 1289 << llvm::StringRef(csStart, csLen) 1290 << getSpecifierRange(startSpec, specifierLen); 1291 1292 return keepGoing; 1293} 1294 1295bool 1296CheckFormatHandler::CheckNumArgs( 1297 const analyze_format_string::FormatSpecifier &FS, 1298 const analyze_format_string::ConversionSpecifier &CS, 1299 const char *startSpecifier, unsigned specifierLen, unsigned argIndex) { 1300 1301 if (argIndex >= NumDataArgs) { 1302 if (FS.usesPositionalArg()) { 1303 S.Diag(getLocationOfByte(CS.getStart()), 1304 diag::warn_printf_positional_arg_exceeds_data_args) 1305 << (argIndex+1) << NumDataArgs 1306 << getSpecifierRange(startSpecifier, specifierLen); 1307 } 1308 else { 1309 S.Diag(getLocationOfByte(CS.getStart()), 1310 diag::warn_printf_insufficient_data_args) 1311 << getSpecifierRange(startSpecifier, specifierLen); 1312 } 1313 1314 return false; 1315 } 1316 return true; 1317} 1318 1319//===--- CHECK: Printf format string checking ------------------------------===// 1320 1321namespace { 1322class CheckPrintfHandler : public CheckFormatHandler { 1323public: 1324 CheckPrintfHandler(Sema &s, const StringLiteral *fexpr, 1325 const Expr *origFormatExpr, unsigned firstDataArg, 1326 unsigned numDataArgs, bool isObjCLiteral, 1327 const char *beg, bool hasVAListArg, 1328 const CallExpr *theCall, unsigned formatIdx) 1329 : CheckFormatHandler(s, fexpr, origFormatExpr, firstDataArg, 1330 numDataArgs, isObjCLiteral, beg, hasVAListArg, 1331 theCall, formatIdx) {} 1332 1333 1334 bool HandleInvalidPrintfConversionSpecifier( 1335 const analyze_printf::PrintfSpecifier &FS, 1336 const char *startSpecifier, 1337 unsigned specifierLen); 1338 1339 bool HandlePrintfSpecifier(const analyze_printf::PrintfSpecifier &FS, 1340 const char *startSpecifier, 1341 unsigned specifierLen); 1342 1343 bool HandleAmount(const analyze_format_string::OptionalAmount &Amt, unsigned k, 1344 const char *startSpecifier, unsigned specifierLen); 1345 void HandleInvalidAmount(const analyze_printf::PrintfSpecifier &FS, 1346 const analyze_printf::OptionalAmount &Amt, 1347 unsigned type, 1348 const char *startSpecifier, unsigned specifierLen); 1349 void HandleFlag(const analyze_printf::PrintfSpecifier &FS, 1350 const analyze_printf::OptionalFlag &flag, 1351 const char *startSpecifier, unsigned specifierLen); 1352 void HandleIgnoredFlag(const analyze_printf::PrintfSpecifier &FS, 1353 const analyze_printf::OptionalFlag &ignoredFlag, 1354 const analyze_printf::OptionalFlag &flag, 1355 const char *startSpecifier, unsigned specifierLen); 1356}; 1357} 1358 1359bool CheckPrintfHandler::HandleInvalidPrintfConversionSpecifier( 1360 const analyze_printf::PrintfSpecifier &FS, 1361 const char *startSpecifier, 1362 unsigned specifierLen) { 1363 const analyze_printf::PrintfConversionSpecifier &CS = 1364 FS.getConversionSpecifier(); 1365 1366 return HandleInvalidConversionSpecifier(FS.getArgIndex(), 1367 getLocationOfByte(CS.getStart()), 1368 startSpecifier, specifierLen, 1369 CS.getStart(), CS.getLength()); 1370} 1371 1372bool CheckPrintfHandler::HandleAmount( 1373 const analyze_format_string::OptionalAmount &Amt, 1374 unsigned k, const char *startSpecifier, 1375 unsigned specifierLen) { 1376 1377 if (Amt.hasDataArgument()) { 1378 if (!HasVAListArg) { 1379 unsigned argIndex = Amt.getArgIndex(); 1380 if (argIndex >= NumDataArgs) { 1381 S.Diag(getLocationOfByte(Amt.getStart()), 1382 diag::warn_printf_asterisk_missing_arg) 1383 << k << getSpecifierRange(startSpecifier, specifierLen); 1384 // Don't do any more checking. We will just emit 1385 // spurious errors. 1386 return false; 1387 } 1388 1389 // Type check the data argument. It should be an 'int'. 1390 // Although not in conformance with C99, we also allow the argument to be 1391 // an 'unsigned int' as that is a reasonably safe case. GCC also 1392 // doesn't emit a warning for that case. 1393 CoveredArgs.set(argIndex); 1394 const Expr *Arg = getDataArg(argIndex); 1395 QualType T = Arg->getType(); 1396 1397 const analyze_printf::ArgTypeResult &ATR = Amt.getArgType(S.Context); 1398 assert(ATR.isValid()); 1399 1400 if (!ATR.matchesType(S.Context, T)) { 1401 S.Diag(getLocationOfByte(Amt.getStart()), 1402 diag::warn_printf_asterisk_wrong_type) 1403 << k 1404 << ATR.getRepresentativeType(S.Context) << T 1405 << getSpecifierRange(startSpecifier, specifierLen) 1406 << Arg->getSourceRange(); 1407 // Don't do any more checking. We will just emit 1408 // spurious errors. 1409 return false; 1410 } 1411 } 1412 } 1413 return true; 1414} 1415 1416void CheckPrintfHandler::HandleInvalidAmount( 1417 const analyze_printf::PrintfSpecifier &FS, 1418 const analyze_printf::OptionalAmount &Amt, 1419 unsigned type, 1420 const char *startSpecifier, 1421 unsigned specifierLen) { 1422 const analyze_printf::PrintfConversionSpecifier &CS = 1423 FS.getConversionSpecifier(); 1424 switch (Amt.getHowSpecified()) { 1425 case analyze_printf::OptionalAmount::Constant: 1426 S.Diag(getLocationOfByte(Amt.getStart()), 1427 diag::warn_printf_nonsensical_optional_amount) 1428 << type 1429 << CS.toString() 1430 << getSpecifierRange(startSpecifier, specifierLen) 1431 << FixItHint::CreateRemoval(getSpecifierRange(Amt.getStart(), 1432 Amt.getConstantLength())); 1433 break; 1434 1435 default: 1436 S.Diag(getLocationOfByte(Amt.getStart()), 1437 diag::warn_printf_nonsensical_optional_amount) 1438 << type 1439 << CS.toString() 1440 << getSpecifierRange(startSpecifier, specifierLen); 1441 break; 1442 } 1443} 1444 1445void CheckPrintfHandler::HandleFlag(const analyze_printf::PrintfSpecifier &FS, 1446 const analyze_printf::OptionalFlag &flag, 1447 const char *startSpecifier, 1448 unsigned specifierLen) { 1449 // Warn about pointless flag with a fixit removal. 1450 const analyze_printf::PrintfConversionSpecifier &CS = 1451 FS.getConversionSpecifier(); 1452 S.Diag(getLocationOfByte(flag.getPosition()), 1453 diag::warn_printf_nonsensical_flag) 1454 << flag.toString() << CS.toString() 1455 << getSpecifierRange(startSpecifier, specifierLen) 1456 << FixItHint::CreateRemoval(getSpecifierRange(flag.getPosition(), 1)); 1457} 1458 1459void CheckPrintfHandler::HandleIgnoredFlag( 1460 const analyze_printf::PrintfSpecifier &FS, 1461 const analyze_printf::OptionalFlag &ignoredFlag, 1462 const analyze_printf::OptionalFlag &flag, 1463 const char *startSpecifier, 1464 unsigned specifierLen) { 1465 // Warn about ignored flag with a fixit removal. 1466 S.Diag(getLocationOfByte(ignoredFlag.getPosition()), 1467 diag::warn_printf_ignored_flag) 1468 << ignoredFlag.toString() << flag.toString() 1469 << getSpecifierRange(startSpecifier, specifierLen) 1470 << FixItHint::CreateRemoval(getSpecifierRange( 1471 ignoredFlag.getPosition(), 1)); 1472} 1473 1474bool 1475CheckPrintfHandler::HandlePrintfSpecifier(const analyze_printf::PrintfSpecifier 1476 &FS, 1477 const char *startSpecifier, 1478 unsigned specifierLen) { 1479 1480 using namespace analyze_format_string; 1481 using namespace analyze_printf; 1482 const PrintfConversionSpecifier &CS = FS.getConversionSpecifier(); 1483 1484 if (FS.consumesDataArgument()) { 1485 if (atFirstArg) { 1486 atFirstArg = false; 1487 usesPositionalArgs = FS.usesPositionalArg(); 1488 } 1489 else if (usesPositionalArgs != FS.usesPositionalArg()) { 1490 // Cannot mix-and-match positional and non-positional arguments. 1491 S.Diag(getLocationOfByte(CS.getStart()), 1492 diag::warn_format_mix_positional_nonpositional_args) 1493 << getSpecifierRange(startSpecifier, specifierLen); 1494 return false; 1495 } 1496 } 1497 1498 // First check if the field width, precision, and conversion specifier 1499 // have matching data arguments. 1500 if (!HandleAmount(FS.getFieldWidth(), /* field width */ 0, 1501 startSpecifier, specifierLen)) { 1502 return false; 1503 } 1504 1505 if (!HandleAmount(FS.getPrecision(), /* precision */ 1, 1506 startSpecifier, specifierLen)) { 1507 return false; 1508 } 1509 1510 if (!CS.consumesDataArgument()) { 1511 // FIXME: Technically specifying a precision or field width here 1512 // makes no sense. Worth issuing a warning at some point. 1513 return true; 1514 } 1515 1516 // Consume the argument. 1517 unsigned argIndex = FS.getArgIndex(); 1518 if (argIndex < NumDataArgs) { 1519 // The check to see if the argIndex is valid will come later. 1520 // We set the bit here because we may exit early from this 1521 // function if we encounter some other error. 1522 CoveredArgs.set(argIndex); 1523 } 1524 1525 // Check for using an Objective-C specific conversion specifier 1526 // in a non-ObjC literal. 1527 if (!IsObjCLiteral && CS.isObjCArg()) { 1528 return HandleInvalidPrintfConversionSpecifier(FS, startSpecifier, 1529 specifierLen); 1530 } 1531 1532 // Check for invalid use of field width 1533 if (!FS.hasValidFieldWidth()) { 1534 HandleInvalidAmount(FS, FS.getFieldWidth(), /* field width */ 0, 1535 startSpecifier, specifierLen); 1536 } 1537 1538 // Check for invalid use of precision 1539 if (!FS.hasValidPrecision()) { 1540 HandleInvalidAmount(FS, FS.getPrecision(), /* precision */ 1, 1541 startSpecifier, specifierLen); 1542 } 1543 1544 // Check each flag does not conflict with any other component. 1545 if (!FS.hasValidLeadingZeros()) 1546 HandleFlag(FS, FS.hasLeadingZeros(), startSpecifier, specifierLen); 1547 if (!FS.hasValidPlusPrefix()) 1548 HandleFlag(FS, FS.hasPlusPrefix(), startSpecifier, specifierLen); 1549 if (!FS.hasValidSpacePrefix()) 1550 HandleFlag(FS, FS.hasSpacePrefix(), startSpecifier, specifierLen); 1551 if (!FS.hasValidAlternativeForm()) 1552 HandleFlag(FS, FS.hasAlternativeForm(), startSpecifier, specifierLen); 1553 if (!FS.hasValidLeftJustified()) 1554 HandleFlag(FS, FS.isLeftJustified(), startSpecifier, specifierLen); 1555 1556 // Check that flags are not ignored by another flag 1557 if (FS.hasSpacePrefix() && FS.hasPlusPrefix()) // ' ' ignored by '+' 1558 HandleIgnoredFlag(FS, FS.hasSpacePrefix(), FS.hasPlusPrefix(), 1559 startSpecifier, specifierLen); 1560 if (FS.hasLeadingZeros() && FS.isLeftJustified()) // '0' ignored by '-' 1561 HandleIgnoredFlag(FS, FS.hasLeadingZeros(), FS.isLeftJustified(), 1562 startSpecifier, specifierLen); 1563 1564 // Check the length modifier is valid with the given conversion specifier. 1565 const LengthModifier &LM = FS.getLengthModifier(); 1566 if (!FS.hasValidLengthModifier()) 1567 S.Diag(getLocationOfByte(LM.getStart()), 1568 diag::warn_format_nonsensical_length) 1569 << LM.toString() << CS.toString() 1570 << getSpecifierRange(startSpecifier, specifierLen) 1571 << FixItHint::CreateRemoval(getSpecifierRange(LM.getStart(), 1572 LM.getLength())); 1573 1574 // Are we using '%n'? 1575 if (CS.getKind() == ConversionSpecifier::nArg) { 1576 // Issue a warning about this being a possible security issue. 1577 S.Diag(getLocationOfByte(CS.getStart()), diag::warn_printf_write_back) 1578 << getSpecifierRange(startSpecifier, specifierLen); 1579 // Continue checking the other format specifiers. 1580 return true; 1581 } 1582 1583 // The remaining checks depend on the data arguments. 1584 if (HasVAListArg) 1585 return true; 1586 1587 if (!CheckNumArgs(FS, CS, startSpecifier, specifierLen, argIndex)) 1588 return false; 1589 1590 // Now type check the data expression that matches the 1591 // format specifier. 1592 const Expr *Ex = getDataArg(argIndex); 1593 const analyze_printf::ArgTypeResult &ATR = FS.getArgType(S.Context); 1594 if (ATR.isValid() && !ATR.matchesType(S.Context, Ex->getType())) { 1595 // Check if we didn't match because of an implicit cast from a 'char' 1596 // or 'short' to an 'int'. This is done because printf is a varargs 1597 // function. 1598 if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(Ex)) 1599 if (ICE->getType() == S.Context.IntTy) 1600 if (ATR.matchesType(S.Context, ICE->getSubExpr()->getType())) 1601 return true; 1602 1603 // We may be able to offer a FixItHint if it is a supported type. 1604 PrintfSpecifier fixedFS = FS; 1605 bool success = fixedFS.fixType(Ex->getType()); 1606 1607 if (success) { 1608 // Get the fix string from the fixed format specifier 1609 llvm::SmallString<128> buf; 1610 llvm::raw_svector_ostream os(buf); 1611 fixedFS.toString(os); 1612 1613 // FIXME: getRepresentativeType() perhaps should return a string 1614 // instead of a QualType to better handle when the representative 1615 // type is 'wint_t' (which is defined in the system headers). 1616 S.Diag(getLocationOfByte(CS.getStart()), 1617 diag::warn_printf_conversion_argument_type_mismatch) 1618 << ATR.getRepresentativeType(S.Context) << Ex->getType() 1619 << getSpecifierRange(startSpecifier, specifierLen) 1620 << Ex->getSourceRange() 1621 << FixItHint::CreateReplacement( 1622 getSpecifierRange(startSpecifier, specifierLen), 1623 os.str()); 1624 } 1625 else { 1626 S.Diag(getLocationOfByte(CS.getStart()), 1627 diag::warn_printf_conversion_argument_type_mismatch) 1628 << ATR.getRepresentativeType(S.Context) << Ex->getType() 1629 << getSpecifierRange(startSpecifier, specifierLen) 1630 << Ex->getSourceRange(); 1631 } 1632 } 1633 1634 return true; 1635} 1636 1637//===--- CHECK: Scanf format string checking ------------------------------===// 1638 1639namespace { 1640class CheckScanfHandler : public CheckFormatHandler { 1641public: 1642 CheckScanfHandler(Sema &s, const StringLiteral *fexpr, 1643 const Expr *origFormatExpr, unsigned firstDataArg, 1644 unsigned numDataArgs, bool isObjCLiteral, 1645 const char *beg, bool hasVAListArg, 1646 const CallExpr *theCall, unsigned formatIdx) 1647 : CheckFormatHandler(s, fexpr, origFormatExpr, firstDataArg, 1648 numDataArgs, isObjCLiteral, beg, hasVAListArg, 1649 theCall, formatIdx) {} 1650 1651 bool HandleScanfSpecifier(const analyze_scanf::ScanfSpecifier &FS, 1652 const char *startSpecifier, 1653 unsigned specifierLen); 1654 1655 bool HandleInvalidScanfConversionSpecifier( 1656 const analyze_scanf::ScanfSpecifier &FS, 1657 const char *startSpecifier, 1658 unsigned specifierLen); 1659 1660 void HandleIncompleteScanList(const char *start, const char *end); 1661}; 1662} 1663 1664void CheckScanfHandler::HandleIncompleteScanList(const char *start, 1665 const char *end) { 1666 S.Diag(getLocationOfByte(end), diag::warn_scanf_scanlist_incomplete) 1667 << getSpecifierRange(start, end - start); 1668} 1669 1670bool CheckScanfHandler::HandleInvalidScanfConversionSpecifier( 1671 const analyze_scanf::ScanfSpecifier &FS, 1672 const char *startSpecifier, 1673 unsigned specifierLen) { 1674 1675 const analyze_scanf::ScanfConversionSpecifier &CS = 1676 FS.getConversionSpecifier(); 1677 1678 return HandleInvalidConversionSpecifier(FS.getArgIndex(), 1679 getLocationOfByte(CS.getStart()), 1680 startSpecifier, specifierLen, 1681 CS.getStart(), CS.getLength()); 1682} 1683 1684bool CheckScanfHandler::HandleScanfSpecifier( 1685 const analyze_scanf::ScanfSpecifier &FS, 1686 const char *startSpecifier, 1687 unsigned specifierLen) { 1688 1689 using namespace analyze_scanf; 1690 using namespace analyze_format_string; 1691 1692 const ScanfConversionSpecifier &CS = FS.getConversionSpecifier(); 1693 1694 // Handle case where '%' and '*' don't consume an argument. These shouldn't 1695 // be used to decide if we are using positional arguments consistently. 1696 if (FS.consumesDataArgument()) { 1697 if (atFirstArg) { 1698 atFirstArg = false; 1699 usesPositionalArgs = FS.usesPositionalArg(); 1700 } 1701 else if (usesPositionalArgs != FS.usesPositionalArg()) { 1702 // Cannot mix-and-match positional and non-positional arguments. 1703 S.Diag(getLocationOfByte(CS.getStart()), 1704 diag::warn_format_mix_positional_nonpositional_args) 1705 << getSpecifierRange(startSpecifier, specifierLen); 1706 return false; 1707 } 1708 } 1709 1710 // Check if the field with is non-zero. 1711 const OptionalAmount &Amt = FS.getFieldWidth(); 1712 if (Amt.getHowSpecified() == OptionalAmount::Constant) { 1713 if (Amt.getConstantAmount() == 0) { 1714 const CharSourceRange &R = getSpecifierRange(Amt.getStart(), 1715 Amt.getConstantLength()); 1716 S.Diag(getLocationOfByte(Amt.getStart()), 1717 diag::warn_scanf_nonzero_width) 1718 << R << FixItHint::CreateRemoval(R); 1719 } 1720 } 1721 1722 if (!FS.consumesDataArgument()) { 1723 // FIXME: Technically specifying a precision or field width here 1724 // makes no sense. Worth issuing a warning at some point. 1725 return true; 1726 } 1727 1728 // Consume the argument. 1729 unsigned argIndex = FS.getArgIndex(); 1730 if (argIndex < NumDataArgs) { 1731 // The check to see if the argIndex is valid will come later. 1732 // We set the bit here because we may exit early from this 1733 // function if we encounter some other error. 1734 CoveredArgs.set(argIndex); 1735 } 1736 1737 // Check the length modifier is valid with the given conversion specifier. 1738 const LengthModifier &LM = FS.getLengthModifier(); 1739 if (!FS.hasValidLengthModifier()) { 1740 S.Diag(getLocationOfByte(LM.getStart()), 1741 diag::warn_format_nonsensical_length) 1742 << LM.toString() << CS.toString() 1743 << getSpecifierRange(startSpecifier, specifierLen) 1744 << FixItHint::CreateRemoval(getSpecifierRange(LM.getStart(), 1745 LM.getLength())); 1746 } 1747 1748 // The remaining checks depend on the data arguments. 1749 if (HasVAListArg) 1750 return true; 1751 1752 if (!CheckNumArgs(FS, CS, startSpecifier, specifierLen, argIndex)) 1753 return false; 1754 1755 // FIXME: Check that the argument type matches the format specifier. 1756 1757 return true; 1758} 1759 1760void Sema::CheckFormatString(const StringLiteral *FExpr, 1761 const Expr *OrigFormatExpr, 1762 const CallExpr *TheCall, bool HasVAListArg, 1763 unsigned format_idx, unsigned firstDataArg, 1764 bool isPrintf) { 1765 1766 // CHECK: is the format string a wide literal? 1767 if (FExpr->isWide()) { 1768 Diag(FExpr->getLocStart(), 1769 diag::warn_format_string_is_wide_literal) 1770 << OrigFormatExpr->getSourceRange(); 1771 return; 1772 } 1773 1774 // Str - The format string. NOTE: this is NOT null-terminated! 1775 llvm::StringRef StrRef = FExpr->getString(); 1776 const char *Str = StrRef.data(); 1777 unsigned StrLen = StrRef.size(); 1778 1779 // CHECK: empty format string? 1780 if (StrLen == 0) { 1781 Diag(FExpr->getLocStart(), diag::warn_empty_format_string) 1782 << OrigFormatExpr->getSourceRange(); 1783 return; 1784 } 1785 1786 if (isPrintf) { 1787 CheckPrintfHandler H(*this, FExpr, OrigFormatExpr, firstDataArg, 1788 TheCall->getNumArgs() - firstDataArg, 1789 isa<ObjCStringLiteral>(OrigFormatExpr), Str, 1790 HasVAListArg, TheCall, format_idx); 1791 1792 if (!analyze_format_string::ParsePrintfString(H, Str, Str + StrLen)) 1793 H.DoneProcessing(); 1794 } 1795 else { 1796 CheckScanfHandler H(*this, FExpr, OrigFormatExpr, firstDataArg, 1797 TheCall->getNumArgs() - firstDataArg, 1798 isa<ObjCStringLiteral>(OrigFormatExpr), Str, 1799 HasVAListArg, TheCall, format_idx); 1800 1801 if (!analyze_format_string::ParseScanfString(H, Str, Str + StrLen)) 1802 H.DoneProcessing(); 1803 } 1804} 1805 1806//===--- CHECK: Return Address of Stack Variable --------------------------===// 1807 1808static DeclRefExpr* EvalVal(Expr *E); 1809static DeclRefExpr* EvalAddr(Expr* E); 1810 1811/// CheckReturnStackAddr - Check if a return statement returns the address 1812/// of a stack variable. 1813void 1814Sema::CheckReturnStackAddr(Expr *RetValExp, QualType lhsType, 1815 SourceLocation ReturnLoc) { 1816 1817 // Perform checking for returned stack addresses. 1818 if (lhsType->isPointerType() || lhsType->isBlockPointerType()) { 1819 if (DeclRefExpr *DR = EvalAddr(RetValExp)) 1820 Diag(DR->getLocStart(), diag::warn_ret_stack_addr) 1821 << DR->getDecl()->getDeclName() << RetValExp->getSourceRange(); 1822 1823 // Skip over implicit cast expressions when checking for block expressions. 1824 RetValExp = RetValExp->IgnoreParenCasts(); 1825 1826 if (BlockExpr *C = dyn_cast<BlockExpr>(RetValExp)) 1827 if (C->hasBlockDeclRefExprs()) 1828 Diag(C->getLocStart(), diag::err_ret_local_block) 1829 << C->getSourceRange(); 1830 1831 if (AddrLabelExpr *ALE = dyn_cast<AddrLabelExpr>(RetValExp)) 1832 Diag(ALE->getLocStart(), diag::warn_ret_addr_label) 1833 << ALE->getSourceRange(); 1834 1835 } else if (lhsType->isReferenceType()) { 1836 // Perform checking for stack values returned by reference. 1837 // Check for a reference to the stack 1838 if (DeclRefExpr *DR = EvalVal(RetValExp)) 1839 Diag(DR->getLocStart(), diag::warn_ret_stack_ref) 1840 << DR->getDecl()->getDeclName() << RetValExp->getSourceRange(); 1841 } 1842} 1843 1844/// EvalAddr - EvalAddr and EvalVal are mutually recursive functions that 1845/// check if the expression in a return statement evaluates to an address 1846/// to a location on the stack. The recursion is used to traverse the 1847/// AST of the return expression, with recursion backtracking when we 1848/// encounter a subexpression that (1) clearly does not lead to the address 1849/// of a stack variable or (2) is something we cannot determine leads to 1850/// the address of a stack variable based on such local checking. 1851/// 1852/// EvalAddr processes expressions that are pointers that are used as 1853/// references (and not L-values). EvalVal handles all other values. 1854/// At the base case of the recursion is a check for a DeclRefExpr* in 1855/// the refers to a stack variable. 1856/// 1857/// This implementation handles: 1858/// 1859/// * pointer-to-pointer casts 1860/// * implicit conversions from array references to pointers 1861/// * taking the address of fields 1862/// * arbitrary interplay between "&" and "*" operators 1863/// * pointer arithmetic from an address of a stack variable 1864/// * taking the address of an array element where the array is on the stack 1865static DeclRefExpr* EvalAddr(Expr *E) { 1866 // We should only be called for evaluating pointer expressions. 1867 assert((E->getType()->isAnyPointerType() || 1868 E->getType()->isBlockPointerType() || 1869 E->getType()->isObjCQualifiedIdType()) && 1870 "EvalAddr only works on pointers"); 1871 1872 // Our "symbolic interpreter" is just a dispatch off the currently 1873 // viewed AST node. We then recursively traverse the AST by calling 1874 // EvalAddr and EvalVal appropriately. 1875 switch (E->getStmtClass()) { 1876 case Stmt::ParenExprClass: 1877 // Ignore parentheses. 1878 return EvalAddr(cast<ParenExpr>(E)->getSubExpr()); 1879 1880 case Stmt::UnaryOperatorClass: { 1881 // The only unary operator that make sense to handle here 1882 // is AddrOf. All others don't make sense as pointers. 1883 UnaryOperator *U = cast<UnaryOperator>(E); 1884 1885 if (U->getOpcode() == UO_AddrOf) 1886 return EvalVal(U->getSubExpr()); 1887 else 1888 return NULL; 1889 } 1890 1891 case Stmt::BinaryOperatorClass: { 1892 // Handle pointer arithmetic. All other binary operators are not valid 1893 // in this context. 1894 BinaryOperator *B = cast<BinaryOperator>(E); 1895 BinaryOperatorKind op = B->getOpcode(); 1896 1897 if (op != BO_Add && op != BO_Sub) 1898 return NULL; 1899 1900 Expr *Base = B->getLHS(); 1901 1902 // Determine which argument is the real pointer base. It could be 1903 // the RHS argument instead of the LHS. 1904 if (!Base->getType()->isPointerType()) Base = B->getRHS(); 1905 1906 assert (Base->getType()->isPointerType()); 1907 return EvalAddr(Base); 1908 } 1909 1910 // For conditional operators we need to see if either the LHS or RHS are 1911 // valid DeclRefExpr*s. If one of them is valid, we return it. 1912 case Stmt::ConditionalOperatorClass: { 1913 ConditionalOperator *C = cast<ConditionalOperator>(E); 1914 1915 // Handle the GNU extension for missing LHS. 1916 if (Expr *lhsExpr = C->getLHS()) 1917 if (DeclRefExpr* LHS = EvalAddr(lhsExpr)) 1918 return LHS; 1919 1920 return EvalAddr(C->getRHS()); 1921 } 1922 1923 // For casts, we need to handle conversions from arrays to 1924 // pointer values, and pointer-to-pointer conversions. 1925 case Stmt::ImplicitCastExprClass: 1926 case Stmt::CStyleCastExprClass: 1927 case Stmt::CXXFunctionalCastExprClass: { 1928 Expr* SubExpr = cast<CastExpr>(E)->getSubExpr(); 1929 QualType T = SubExpr->getType(); 1930 1931 if (SubExpr->getType()->isPointerType() || 1932 SubExpr->getType()->isBlockPointerType() || 1933 SubExpr->getType()->isObjCQualifiedIdType()) 1934 return EvalAddr(SubExpr); 1935 else if (T->isArrayType()) 1936 return EvalVal(SubExpr); 1937 else 1938 return 0; 1939 } 1940 1941 // C++ casts. For dynamic casts, static casts, and const casts, we 1942 // are always converting from a pointer-to-pointer, so we just blow 1943 // through the cast. In the case the dynamic cast doesn't fail (and 1944 // return NULL), we take the conservative route and report cases 1945 // where we return the address of a stack variable. For Reinterpre 1946 // FIXME: The comment about is wrong; we're not always converting 1947 // from pointer to pointer. I'm guessing that this code should also 1948 // handle references to objects. 1949 case Stmt::CXXStaticCastExprClass: 1950 case Stmt::CXXDynamicCastExprClass: 1951 case Stmt::CXXConstCastExprClass: 1952 case Stmt::CXXReinterpretCastExprClass: { 1953 Expr *S = cast<CXXNamedCastExpr>(E)->getSubExpr(); 1954 if (S->getType()->isPointerType() || S->getType()->isBlockPointerType()) 1955 return EvalAddr(S); 1956 else 1957 return NULL; 1958 } 1959 1960 // Everything else: we simply don't reason about them. 1961 default: 1962 return NULL; 1963 } 1964} 1965 1966 1967/// EvalVal - This function is complements EvalAddr in the mutual recursion. 1968/// See the comments for EvalAddr for more details. 1969static DeclRefExpr* EvalVal(Expr *E) { 1970do { 1971 // We should only be called for evaluating non-pointer expressions, or 1972 // expressions with a pointer type that are not used as references but instead 1973 // are l-values (e.g., DeclRefExpr with a pointer type). 1974 1975 // Our "symbolic interpreter" is just a dispatch off the currently 1976 // viewed AST node. We then recursively traverse the AST by calling 1977 // EvalAddr and EvalVal appropriately. 1978 switch (E->getStmtClass()) { 1979 case Stmt::ImplicitCastExprClass: { 1980 ImplicitCastExpr *IE = cast<ImplicitCastExpr>(E); 1981 if (IE->getValueKind() == VK_LValue) { 1982 E = IE->getSubExpr(); 1983 continue; 1984 } 1985 return NULL; 1986 } 1987 1988 case Stmt::DeclRefExprClass: { 1989 // DeclRefExpr: the base case. When we hit a DeclRefExpr we are looking 1990 // at code that refers to a variable's name. We check if it has local 1991 // storage within the function, and if so, return the expression. 1992 DeclRefExpr *DR = cast<DeclRefExpr>(E); 1993 1994 if (VarDecl *V = dyn_cast<VarDecl>(DR->getDecl())) 1995 if (V->hasLocalStorage() && !V->getType()->isReferenceType()) return DR; 1996 1997 return NULL; 1998 } 1999 2000 case Stmt::ParenExprClass: { 2001 // Ignore parentheses. 2002 E = cast<ParenExpr>(E)->getSubExpr(); 2003 continue; 2004 } 2005 2006 case Stmt::UnaryOperatorClass: { 2007 // The only unary operator that make sense to handle here 2008 // is Deref. All others don't resolve to a "name." This includes 2009 // handling all sorts of rvalues passed to a unary operator. 2010 UnaryOperator *U = cast<UnaryOperator>(E); 2011 2012 if (U->getOpcode() == UO_Deref) 2013 return EvalAddr(U->getSubExpr()); 2014 2015 return NULL; 2016 } 2017 2018 case Stmt::ArraySubscriptExprClass: { 2019 // Array subscripts are potential references to data on the stack. We 2020 // retrieve the DeclRefExpr* for the array variable if it indeed 2021 // has local storage. 2022 return EvalAddr(cast<ArraySubscriptExpr>(E)->getBase()); 2023 } 2024 2025 case Stmt::ConditionalOperatorClass: { 2026 // For conditional operators we need to see if either the LHS or RHS are 2027 // non-NULL DeclRefExpr's. If one is non-NULL, we return it. 2028 ConditionalOperator *C = cast<ConditionalOperator>(E); 2029 2030 // Handle the GNU extension for missing LHS. 2031 if (Expr *lhsExpr = C->getLHS()) 2032 if (DeclRefExpr *LHS = EvalVal(lhsExpr)) 2033 return LHS; 2034 2035 return EvalVal(C->getRHS()); 2036 } 2037 2038 // Accesses to members are potential references to data on the stack. 2039 case Stmt::MemberExprClass: { 2040 MemberExpr *M = cast<MemberExpr>(E); 2041 2042 // Check for indirect access. We only want direct field accesses. 2043 if (M->isArrow()) 2044 return NULL; 2045 2046 // Check whether the member type is itself a reference, in which case 2047 // we're not going to refer to the member, but to what the member refers to. 2048 if (M->getMemberDecl()->getType()->isReferenceType()) 2049 return NULL; 2050 2051 return EvalVal(M->getBase()); 2052 } 2053 2054 // Everything else: we simply don't reason about them. 2055 default: 2056 return NULL; 2057 } 2058} while (true); 2059} 2060 2061//===--- CHECK: Floating-Point comparisons (-Wfloat-equal) ---------------===// 2062 2063/// Check for comparisons of floating point operands using != and ==. 2064/// Issue a warning if these are no self-comparisons, as they are not likely 2065/// to do what the programmer intended. 2066void Sema::CheckFloatComparison(SourceLocation loc, Expr* lex, Expr *rex) { 2067 bool EmitWarning = true; 2068 2069 Expr* LeftExprSansParen = lex->IgnoreParens(); 2070 Expr* RightExprSansParen = rex->IgnoreParens(); 2071 2072 // Special case: check for x == x (which is OK). 2073 // Do not emit warnings for such cases. 2074 if (DeclRefExpr* DRL = dyn_cast<DeclRefExpr>(LeftExprSansParen)) 2075 if (DeclRefExpr* DRR = dyn_cast<DeclRefExpr>(RightExprSansParen)) 2076 if (DRL->getDecl() == DRR->getDecl()) 2077 EmitWarning = false; 2078 2079 2080 // Special case: check for comparisons against literals that can be exactly 2081 // represented by APFloat. In such cases, do not emit a warning. This 2082 // is a heuristic: often comparison against such literals are used to 2083 // detect if a value in a variable has not changed. This clearly can 2084 // lead to false negatives. 2085 if (EmitWarning) { 2086 if (FloatingLiteral* FLL = dyn_cast<FloatingLiteral>(LeftExprSansParen)) { 2087 if (FLL->isExact()) 2088 EmitWarning = false; 2089 } else 2090 if (FloatingLiteral* FLR = dyn_cast<FloatingLiteral>(RightExprSansParen)){ 2091 if (FLR->isExact()) 2092 EmitWarning = false; 2093 } 2094 } 2095 2096 // Check for comparisons with builtin types. 2097 if (EmitWarning) 2098 if (CallExpr* CL = dyn_cast<CallExpr>(LeftExprSansParen)) 2099 if (CL->isBuiltinCall(Context)) 2100 EmitWarning = false; 2101 2102 if (EmitWarning) 2103 if (CallExpr* CR = dyn_cast<CallExpr>(RightExprSansParen)) 2104 if (CR->isBuiltinCall(Context)) 2105 EmitWarning = false; 2106 2107 // Emit the diagnostic. 2108 if (EmitWarning) 2109 Diag(loc, diag::warn_floatingpoint_eq) 2110 << lex->getSourceRange() << rex->getSourceRange(); 2111} 2112 2113//===--- CHECK: Integer mixed-sign comparisons (-Wsign-compare) --------===// 2114//===--- CHECK: Lossy implicit conversions (-Wconversion) --------------===// 2115 2116namespace { 2117 2118/// Structure recording the 'active' range of an integer-valued 2119/// expression. 2120struct IntRange { 2121 /// The number of bits active in the int. 2122 unsigned Width; 2123 2124 /// True if the int is known not to have negative values. 2125 bool NonNegative; 2126 2127 IntRange(unsigned Width, bool NonNegative) 2128 : Width(Width), NonNegative(NonNegative) 2129 {} 2130 2131 // Returns the range of the bool type. 2132 static IntRange forBoolType() { 2133 return IntRange(1, true); 2134 } 2135 2136 // Returns the range of an integral type. 2137 static IntRange forType(ASTContext &C, QualType T) { 2138 return forCanonicalType(C, T->getCanonicalTypeInternal().getTypePtr()); 2139 } 2140 2141 // Returns the range of an integeral type based on its canonical 2142 // representation. 2143 static IntRange forCanonicalType(ASTContext &C, const Type *T) { 2144 assert(T->isCanonicalUnqualified()); 2145 2146 if (const VectorType *VT = dyn_cast<VectorType>(T)) 2147 T = VT->getElementType().getTypePtr(); 2148 if (const ComplexType *CT = dyn_cast<ComplexType>(T)) 2149 T = CT->getElementType().getTypePtr(); 2150 2151 if (const EnumType *ET = dyn_cast<EnumType>(T)) { 2152 EnumDecl *Enum = ET->getDecl(); 2153 unsigned NumPositive = Enum->getNumPositiveBits(); 2154 unsigned NumNegative = Enum->getNumNegativeBits(); 2155 2156 return IntRange(std::max(NumPositive, NumNegative), NumNegative == 0); 2157 } 2158 2159 const BuiltinType *BT = cast<BuiltinType>(T); 2160 assert(BT->isInteger()); 2161 2162 return IntRange(C.getIntWidth(QualType(T, 0)), BT->isUnsignedInteger()); 2163 } 2164 2165 // Returns the supremum of two ranges: i.e. their conservative merge. 2166 static IntRange join(IntRange L, IntRange R) { 2167 return IntRange(std::max(L.Width, R.Width), 2168 L.NonNegative && R.NonNegative); 2169 } 2170 2171 // Returns the infinum of two ranges: i.e. their aggressive merge. 2172 static IntRange meet(IntRange L, IntRange R) { 2173 return IntRange(std::min(L.Width, R.Width), 2174 L.NonNegative || R.NonNegative); 2175 } 2176}; 2177 2178IntRange GetValueRange(ASTContext &C, llvm::APSInt &value, unsigned MaxWidth) { 2179 if (value.isSigned() && value.isNegative()) 2180 return IntRange(value.getMinSignedBits(), false); 2181 2182 if (value.getBitWidth() > MaxWidth) 2183 value.trunc(MaxWidth); 2184 2185 // isNonNegative() just checks the sign bit without considering 2186 // signedness. 2187 return IntRange(value.getActiveBits(), true); 2188} 2189 2190IntRange GetValueRange(ASTContext &C, APValue &result, QualType Ty, 2191 unsigned MaxWidth) { 2192 if (result.isInt()) 2193 return GetValueRange(C, result.getInt(), MaxWidth); 2194 2195 if (result.isVector()) { 2196 IntRange R = GetValueRange(C, result.getVectorElt(0), Ty, MaxWidth); 2197 for (unsigned i = 1, e = result.getVectorLength(); i != e; ++i) { 2198 IntRange El = GetValueRange(C, result.getVectorElt(i), Ty, MaxWidth); 2199 R = IntRange::join(R, El); 2200 } 2201 return R; 2202 } 2203 2204 if (result.isComplexInt()) { 2205 IntRange R = GetValueRange(C, result.getComplexIntReal(), MaxWidth); 2206 IntRange I = GetValueRange(C, result.getComplexIntImag(), MaxWidth); 2207 return IntRange::join(R, I); 2208 } 2209 2210 // This can happen with lossless casts to intptr_t of "based" lvalues. 2211 // Assume it might use arbitrary bits. 2212 // FIXME: The only reason we need to pass the type in here is to get 2213 // the sign right on this one case. It would be nice if APValue 2214 // preserved this. 2215 assert(result.isLValue()); 2216 return IntRange(MaxWidth, Ty->isUnsignedIntegerType()); 2217} 2218 2219/// Pseudo-evaluate the given integer expression, estimating the 2220/// range of values it might take. 2221/// 2222/// \param MaxWidth - the width to which the value will be truncated 2223IntRange GetExprRange(ASTContext &C, Expr *E, unsigned MaxWidth) { 2224 E = E->IgnoreParens(); 2225 2226 // Try a full evaluation first. 2227 Expr::EvalResult result; 2228 if (E->Evaluate(result, C)) 2229 return GetValueRange(C, result.Val, E->getType(), MaxWidth); 2230 2231 // I think we only want to look through implicit casts here; if the 2232 // user has an explicit widening cast, we should treat the value as 2233 // being of the new, wider type. 2234 if (ImplicitCastExpr *CE = dyn_cast<ImplicitCastExpr>(E)) { 2235 if (CE->getCastKind() == CK_NoOp) 2236 return GetExprRange(C, CE->getSubExpr(), MaxWidth); 2237 2238 IntRange OutputTypeRange = IntRange::forType(C, CE->getType()); 2239 2240 bool isIntegerCast = (CE->getCastKind() == CK_IntegralCast); 2241 if (!isIntegerCast && CE->getCastKind() == CK_Unknown) 2242 isIntegerCast = CE->getSubExpr()->getType()->isIntegerType(); 2243 2244 // Assume that non-integer casts can span the full range of the type. 2245 if (!isIntegerCast) 2246 return OutputTypeRange; 2247 2248 IntRange SubRange 2249 = GetExprRange(C, CE->getSubExpr(), 2250 std::min(MaxWidth, OutputTypeRange.Width)); 2251 2252 // Bail out if the subexpr's range is as wide as the cast type. 2253 if (SubRange.Width >= OutputTypeRange.Width) 2254 return OutputTypeRange; 2255 2256 // Otherwise, we take the smaller width, and we're non-negative if 2257 // either the output type or the subexpr is. 2258 return IntRange(SubRange.Width, 2259 SubRange.NonNegative || OutputTypeRange.NonNegative); 2260 } 2261 2262 if (ConditionalOperator *CO = dyn_cast<ConditionalOperator>(E)) { 2263 // If we can fold the condition, just take that operand. 2264 bool CondResult; 2265 if (CO->getCond()->EvaluateAsBooleanCondition(CondResult, C)) 2266 return GetExprRange(C, CondResult ? CO->getTrueExpr() 2267 : CO->getFalseExpr(), 2268 MaxWidth); 2269 2270 // Otherwise, conservatively merge. 2271 IntRange L = GetExprRange(C, CO->getTrueExpr(), MaxWidth); 2272 IntRange R = GetExprRange(C, CO->getFalseExpr(), MaxWidth); 2273 return IntRange::join(L, R); 2274 } 2275 2276 if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) { 2277 switch (BO->getOpcode()) { 2278 2279 // Boolean-valued operations are single-bit and positive. 2280 case BO_LAnd: 2281 case BO_LOr: 2282 case BO_LT: 2283 case BO_GT: 2284 case BO_LE: 2285 case BO_GE: 2286 case BO_EQ: 2287 case BO_NE: 2288 return IntRange::forBoolType(); 2289 2290 // The type of these compound assignments is the type of the LHS, 2291 // so the RHS is not necessarily an integer. 2292 case BO_MulAssign: 2293 case BO_DivAssign: 2294 case BO_RemAssign: 2295 case BO_AddAssign: 2296 case BO_SubAssign: 2297 return IntRange::forType(C, E->getType()); 2298 2299 // Operations with opaque sources are black-listed. 2300 case BO_PtrMemD: 2301 case BO_PtrMemI: 2302 return IntRange::forType(C, E->getType()); 2303 2304 // Bitwise-and uses the *infinum* of the two source ranges. 2305 case BO_And: 2306 case BO_AndAssign: 2307 return IntRange::meet(GetExprRange(C, BO->getLHS(), MaxWidth), 2308 GetExprRange(C, BO->getRHS(), MaxWidth)); 2309 2310 // Left shift gets black-listed based on a judgement call. 2311 case BO_Shl: 2312 // ...except that we want to treat '1 << (blah)' as logically 2313 // positive. It's an important idiom. 2314 if (IntegerLiteral *I 2315 = dyn_cast<IntegerLiteral>(BO->getLHS()->IgnoreParenCasts())) { 2316 if (I->getValue() == 1) { 2317 IntRange R = IntRange::forType(C, E->getType()); 2318 return IntRange(R.Width, /*NonNegative*/ true); 2319 } 2320 } 2321 // fallthrough 2322 2323 case BO_ShlAssign: 2324 return IntRange::forType(C, E->getType()); 2325 2326 // Right shift by a constant can narrow its left argument. 2327 case BO_Shr: 2328 case BO_ShrAssign: { 2329 IntRange L = GetExprRange(C, BO->getLHS(), MaxWidth); 2330 2331 // If the shift amount is a positive constant, drop the width by 2332 // that much. 2333 llvm::APSInt shift; 2334 if (BO->getRHS()->isIntegerConstantExpr(shift, C) && 2335 shift.isNonNegative()) { 2336 unsigned zext = shift.getZExtValue(); 2337 if (zext >= L.Width) 2338 L.Width = (L.NonNegative ? 0 : 1); 2339 else 2340 L.Width -= zext; 2341 } 2342 2343 return L; 2344 } 2345 2346 // Comma acts as its right operand. 2347 case BO_Comma: 2348 return GetExprRange(C, BO->getRHS(), MaxWidth); 2349 2350 // Black-list pointer subtractions. 2351 case BO_Sub: 2352 if (BO->getLHS()->getType()->isPointerType()) 2353 return IntRange::forType(C, E->getType()); 2354 // fallthrough 2355 2356 default: 2357 break; 2358 } 2359 2360 // Treat every other operator as if it were closed on the 2361 // narrowest type that encompasses both operands. 2362 IntRange L = GetExprRange(C, BO->getLHS(), MaxWidth); 2363 IntRange R = GetExprRange(C, BO->getRHS(), MaxWidth); 2364 return IntRange::join(L, R); 2365 } 2366 2367 if (UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) { 2368 switch (UO->getOpcode()) { 2369 // Boolean-valued operations are white-listed. 2370 case UO_LNot: 2371 return IntRange::forBoolType(); 2372 2373 // Operations with opaque sources are black-listed. 2374 case UO_Deref: 2375 case UO_AddrOf: // should be impossible 2376 return IntRange::forType(C, E->getType()); 2377 2378 default: 2379 return GetExprRange(C, UO->getSubExpr(), MaxWidth); 2380 } 2381 } 2382 2383 if (dyn_cast<OffsetOfExpr>(E)) { 2384 IntRange::forType(C, E->getType()); 2385 } 2386 2387 FieldDecl *BitField = E->getBitField(); 2388 if (BitField) { 2389 llvm::APSInt BitWidthAP = BitField->getBitWidth()->EvaluateAsInt(C); 2390 unsigned BitWidth = BitWidthAP.getZExtValue(); 2391 2392 return IntRange(BitWidth, BitField->getType()->isUnsignedIntegerType()); 2393 } 2394 2395 return IntRange::forType(C, E->getType()); 2396} 2397 2398IntRange GetExprRange(ASTContext &C, Expr *E) { 2399 return GetExprRange(C, E, C.getIntWidth(E->getType())); 2400} 2401 2402/// Checks whether the given value, which currently has the given 2403/// source semantics, has the same value when coerced through the 2404/// target semantics. 2405bool IsSameFloatAfterCast(const llvm::APFloat &value, 2406 const llvm::fltSemantics &Src, 2407 const llvm::fltSemantics &Tgt) { 2408 llvm::APFloat truncated = value; 2409 2410 bool ignored; 2411 truncated.convert(Src, llvm::APFloat::rmNearestTiesToEven, &ignored); 2412 truncated.convert(Tgt, llvm::APFloat::rmNearestTiesToEven, &ignored); 2413 2414 return truncated.bitwiseIsEqual(value); 2415} 2416 2417/// Checks whether the given value, which currently has the given 2418/// source semantics, has the same value when coerced through the 2419/// target semantics. 2420/// 2421/// The value might be a vector of floats (or a complex number). 2422bool IsSameFloatAfterCast(const APValue &value, 2423 const llvm::fltSemantics &Src, 2424 const llvm::fltSemantics &Tgt) { 2425 if (value.isFloat()) 2426 return IsSameFloatAfterCast(value.getFloat(), Src, Tgt); 2427 2428 if (value.isVector()) { 2429 for (unsigned i = 0, e = value.getVectorLength(); i != e; ++i) 2430 if (!IsSameFloatAfterCast(value.getVectorElt(i), Src, Tgt)) 2431 return false; 2432 return true; 2433 } 2434 2435 assert(value.isComplexFloat()); 2436 return (IsSameFloatAfterCast(value.getComplexFloatReal(), Src, Tgt) && 2437 IsSameFloatAfterCast(value.getComplexFloatImag(), Src, Tgt)); 2438} 2439 2440void AnalyzeImplicitConversions(Sema &S, Expr *E); 2441 2442bool IsZero(Sema &S, Expr *E) { 2443 llvm::APSInt Value; 2444 return E->isIntegerConstantExpr(Value, S.Context) && Value == 0; 2445} 2446 2447void CheckTrivialUnsignedComparison(Sema &S, BinaryOperator *E) { 2448 BinaryOperatorKind op = E->getOpcode(); 2449 if (op == BO_LT && IsZero(S, E->getRHS())) { 2450 S.Diag(E->getOperatorLoc(), diag::warn_lunsigned_always_true_comparison) 2451 << "< 0" << "false" 2452 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); 2453 } else if (op == BO_GE && IsZero(S, E->getRHS())) { 2454 S.Diag(E->getOperatorLoc(), diag::warn_lunsigned_always_true_comparison) 2455 << ">= 0" << "true" 2456 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); 2457 } else if (op == BO_GT && IsZero(S, E->getLHS())) { 2458 S.Diag(E->getOperatorLoc(), diag::warn_runsigned_always_true_comparison) 2459 << "0 >" << "false" 2460 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); 2461 } else if (op == BO_LE && IsZero(S, E->getLHS())) { 2462 S.Diag(E->getOperatorLoc(), diag::warn_runsigned_always_true_comparison) 2463 << "0 <=" << "true" 2464 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange(); 2465 } 2466} 2467 2468/// Analyze the operands of the given comparison. Implements the 2469/// fallback case from AnalyzeComparison. 2470void AnalyzeImpConvsInComparison(Sema &S, BinaryOperator *E) { 2471 AnalyzeImplicitConversions(S, E->getLHS()); 2472 AnalyzeImplicitConversions(S, E->getRHS()); 2473} 2474 2475/// \brief Implements -Wsign-compare. 2476/// 2477/// \param lex the left-hand expression 2478/// \param rex the right-hand expression 2479/// \param OpLoc the location of the joining operator 2480/// \param BinOpc binary opcode or 0 2481void AnalyzeComparison(Sema &S, BinaryOperator *E) { 2482 // The type the comparison is being performed in. 2483 QualType T = E->getLHS()->getType(); 2484 assert(S.Context.hasSameUnqualifiedType(T, E->getRHS()->getType()) 2485 && "comparison with mismatched types"); 2486 2487 // We don't do anything special if this isn't an unsigned integral 2488 // comparison: we're only interested in integral comparisons, and 2489 // signed comparisons only happen in cases we don't care to warn about. 2490 if (!T->hasUnsignedIntegerRepresentation()) 2491 return AnalyzeImpConvsInComparison(S, E); 2492 2493 Expr *lex = E->getLHS()->IgnoreParenImpCasts(); 2494 Expr *rex = E->getRHS()->IgnoreParenImpCasts(); 2495 2496 // Check to see if one of the (unmodified) operands is of different 2497 // signedness. 2498 Expr *signedOperand, *unsignedOperand; 2499 if (lex->getType()->hasSignedIntegerRepresentation()) { 2500 assert(!rex->getType()->hasSignedIntegerRepresentation() && 2501 "unsigned comparison between two signed integer expressions?"); 2502 signedOperand = lex; 2503 unsignedOperand = rex; 2504 } else if (rex->getType()->hasSignedIntegerRepresentation()) { 2505 signedOperand = rex; 2506 unsignedOperand = lex; 2507 } else { 2508 CheckTrivialUnsignedComparison(S, E); 2509 return AnalyzeImpConvsInComparison(S, E); 2510 } 2511 2512 // Otherwise, calculate the effective range of the signed operand. 2513 IntRange signedRange = GetExprRange(S.Context, signedOperand); 2514 2515 // Go ahead and analyze implicit conversions in the operands. Note 2516 // that we skip the implicit conversions on both sides. 2517 AnalyzeImplicitConversions(S, lex); 2518 AnalyzeImplicitConversions(S, rex); 2519 2520 // If the signed range is non-negative, -Wsign-compare won't fire, 2521 // but we should still check for comparisons which are always true 2522 // or false. 2523 if (signedRange.NonNegative) 2524 return CheckTrivialUnsignedComparison(S, E); 2525 2526 // For (in)equality comparisons, if the unsigned operand is a 2527 // constant which cannot collide with a overflowed signed operand, 2528 // then reinterpreting the signed operand as unsigned will not 2529 // change the result of the comparison. 2530 if (E->isEqualityOp()) { 2531 unsigned comparisonWidth = S.Context.getIntWidth(T); 2532 IntRange unsignedRange = GetExprRange(S.Context, unsignedOperand); 2533 2534 // We should never be unable to prove that the unsigned operand is 2535 // non-negative. 2536 assert(unsignedRange.NonNegative && "unsigned range includes negative?"); 2537 2538 if (unsignedRange.Width < comparisonWidth) 2539 return; 2540 } 2541 2542 S.Diag(E->getOperatorLoc(), diag::warn_mixed_sign_comparison) 2543 << lex->getType() << rex->getType() 2544 << lex->getSourceRange() << rex->getSourceRange(); 2545} 2546 2547/// Diagnose an implicit cast; purely a helper for CheckImplicitConversion. 2548void DiagnoseImpCast(Sema &S, Expr *E, QualType T, unsigned diag) { 2549 S.Diag(E->getExprLoc(), diag) << E->getType() << T << E->getSourceRange(); 2550} 2551 2552void CheckImplicitConversion(Sema &S, Expr *E, QualType T, 2553 bool *ICContext = 0) { 2554 if (E->isTypeDependent() || E->isValueDependent()) return; 2555 2556 const Type *Source = S.Context.getCanonicalType(E->getType()).getTypePtr(); 2557 const Type *Target = S.Context.getCanonicalType(T).getTypePtr(); 2558 if (Source == Target) return; 2559 if (Target->isDependentType()) return; 2560 2561 // Never diagnose implicit casts to bool. 2562 if (Target->isSpecificBuiltinType(BuiltinType::Bool)) 2563 return; 2564 2565 // Strip vector types. 2566 if (isa<VectorType>(Source)) { 2567 if (!isa<VectorType>(Target)) 2568 return DiagnoseImpCast(S, E, T, diag::warn_impcast_vector_scalar); 2569 2570 Source = cast<VectorType>(Source)->getElementType().getTypePtr(); 2571 Target = cast<VectorType>(Target)->getElementType().getTypePtr(); 2572 } 2573 2574 // Strip complex types. 2575 if (isa<ComplexType>(Source)) { 2576 if (!isa<ComplexType>(Target)) 2577 return DiagnoseImpCast(S, E, T, diag::warn_impcast_complex_scalar); 2578 2579 Source = cast<ComplexType>(Source)->getElementType().getTypePtr(); 2580 Target = cast<ComplexType>(Target)->getElementType().getTypePtr(); 2581 } 2582 2583 const BuiltinType *SourceBT = dyn_cast<BuiltinType>(Source); 2584 const BuiltinType *TargetBT = dyn_cast<BuiltinType>(Target); 2585 2586 // If the source is floating point... 2587 if (SourceBT && SourceBT->isFloatingPoint()) { 2588 // ...and the target is floating point... 2589 if (TargetBT && TargetBT->isFloatingPoint()) { 2590 // ...then warn if we're dropping FP rank. 2591 2592 // Builtin FP kinds are ordered by increasing FP rank. 2593 if (SourceBT->getKind() > TargetBT->getKind()) { 2594 // Don't warn about float constants that are precisely 2595 // representable in the target type. 2596 Expr::EvalResult result; 2597 if (E->Evaluate(result, S.Context)) { 2598 // Value might be a float, a float vector, or a float complex. 2599 if (IsSameFloatAfterCast(result.Val, 2600 S.Context.getFloatTypeSemantics(QualType(TargetBT, 0)), 2601 S.Context.getFloatTypeSemantics(QualType(SourceBT, 0)))) 2602 return; 2603 } 2604 2605 DiagnoseImpCast(S, E, T, diag::warn_impcast_float_precision); 2606 } 2607 return; 2608 } 2609 2610 // If the target is integral, always warn. 2611 if ((TargetBT && TargetBT->isInteger())) 2612 // TODO: don't warn for integer values? 2613 DiagnoseImpCast(S, E, T, diag::warn_impcast_float_integer); 2614 2615 return; 2616 } 2617 2618 if (!Source->isIntegerType() || !Target->isIntegerType()) 2619 return; 2620 2621 IntRange SourceRange = GetExprRange(S.Context, E); 2622 IntRange TargetRange = IntRange::forCanonicalType(S.Context, Target); 2623 2624 if (SourceRange.Width > TargetRange.Width) { 2625 // People want to build with -Wshorten-64-to-32 and not -Wconversion 2626 // and by god we'll let them. 2627 if (SourceRange.Width == 64 && TargetRange.Width == 32) 2628 return DiagnoseImpCast(S, E, T, diag::warn_impcast_integer_64_32); 2629 return DiagnoseImpCast(S, E, T, diag::warn_impcast_integer_precision); 2630 } 2631 2632 if ((TargetRange.NonNegative && !SourceRange.NonNegative) || 2633 (!TargetRange.NonNegative && SourceRange.NonNegative && 2634 SourceRange.Width == TargetRange.Width)) { 2635 unsigned DiagID = diag::warn_impcast_integer_sign; 2636 2637 // Traditionally, gcc has warned about this under -Wsign-compare. 2638 // We also want to warn about it in -Wconversion. 2639 // So if -Wconversion is off, use a completely identical diagnostic 2640 // in the sign-compare group. 2641 // The conditional-checking code will 2642 if (ICContext) { 2643 DiagID = diag::warn_impcast_integer_sign_conditional; 2644 *ICContext = true; 2645 } 2646 2647 return DiagnoseImpCast(S, E, T, DiagID); 2648 } 2649 2650 return; 2651} 2652 2653void CheckConditionalOperator(Sema &S, ConditionalOperator *E, QualType T); 2654 2655void CheckConditionalOperand(Sema &S, Expr *E, QualType T, 2656 bool &ICContext) { 2657 E = E->IgnoreParenImpCasts(); 2658 2659 if (isa<ConditionalOperator>(E)) 2660 return CheckConditionalOperator(S, cast<ConditionalOperator>(E), T); 2661 2662 AnalyzeImplicitConversions(S, E); 2663 if (E->getType() != T) 2664 return CheckImplicitConversion(S, E, T, &ICContext); 2665 return; 2666} 2667 2668void CheckConditionalOperator(Sema &S, ConditionalOperator *E, QualType T) { 2669 AnalyzeImplicitConversions(S, E->getCond()); 2670 2671 bool Suspicious = false; 2672 CheckConditionalOperand(S, E->getTrueExpr(), T, Suspicious); 2673 CheckConditionalOperand(S, E->getFalseExpr(), T, Suspicious); 2674 2675 // If -Wconversion would have warned about either of the candidates 2676 // for a signedness conversion to the context type... 2677 if (!Suspicious) return; 2678 2679 // ...but it's currently ignored... 2680 if (S.Diags.getDiagnosticLevel(diag::warn_impcast_integer_sign_conditional)) 2681 return; 2682 2683 // ...and -Wsign-compare isn't... 2684 if (!S.Diags.getDiagnosticLevel(diag::warn_mixed_sign_conditional)) 2685 return; 2686 2687 // ...then check whether it would have warned about either of the 2688 // candidates for a signedness conversion to the condition type. 2689 if (E->getType() != T) { 2690 Suspicious = false; 2691 CheckImplicitConversion(S, E->getTrueExpr()->IgnoreParenImpCasts(), 2692 E->getType(), &Suspicious); 2693 if (!Suspicious) 2694 CheckImplicitConversion(S, E->getFalseExpr()->IgnoreParenImpCasts(), 2695 E->getType(), &Suspicious); 2696 if (!Suspicious) 2697 return; 2698 } 2699 2700 // If so, emit a diagnostic under -Wsign-compare. 2701 Expr *lex = E->getTrueExpr()->IgnoreParenImpCasts(); 2702 Expr *rex = E->getFalseExpr()->IgnoreParenImpCasts(); 2703 S.Diag(E->getQuestionLoc(), diag::warn_mixed_sign_conditional) 2704 << lex->getType() << rex->getType() 2705 << lex->getSourceRange() << rex->getSourceRange(); 2706} 2707 2708/// AnalyzeImplicitConversions - Find and report any interesting 2709/// implicit conversions in the given expression. There are a couple 2710/// of competing diagnostics here, -Wconversion and -Wsign-compare. 2711void AnalyzeImplicitConversions(Sema &S, Expr *OrigE) { 2712 QualType T = OrigE->getType(); 2713 Expr *E = OrigE->IgnoreParenImpCasts(); 2714 2715 // For conditional operators, we analyze the arguments as if they 2716 // were being fed directly into the output. 2717 if (isa<ConditionalOperator>(E)) { 2718 ConditionalOperator *CO = cast<ConditionalOperator>(E); 2719 CheckConditionalOperator(S, CO, T); 2720 return; 2721 } 2722 2723 // Go ahead and check any implicit conversions we might have skipped. 2724 // The non-canonical typecheck is just an optimization; 2725 // CheckImplicitConversion will filter out dead implicit conversions. 2726 if (E->getType() != T) 2727 CheckImplicitConversion(S, E, T); 2728 2729 // Now continue drilling into this expression. 2730 2731 // Skip past explicit casts. 2732 if (isa<ExplicitCastExpr>(E)) { 2733 E = cast<ExplicitCastExpr>(E)->getSubExpr()->IgnoreParenImpCasts(); 2734 return AnalyzeImplicitConversions(S, E); 2735 } 2736 2737 // Do a somewhat different check with comparison operators. 2738 if (isa<BinaryOperator>(E) && cast<BinaryOperator>(E)->isComparisonOp()) 2739 return AnalyzeComparison(S, cast<BinaryOperator>(E)); 2740 2741 // These break the otherwise-useful invariant below. Fortunately, 2742 // we don't really need to recurse into them, because any internal 2743 // expressions should have been analyzed already when they were 2744 // built into statements. 2745 if (isa<StmtExpr>(E)) return; 2746 2747 // Don't descend into unevaluated contexts. 2748 if (isa<SizeOfAlignOfExpr>(E)) return; 2749 2750 // Now just recurse over the expression's children. 2751 for (Stmt::child_iterator I = E->child_begin(), IE = E->child_end(); 2752 I != IE; ++I) 2753 AnalyzeImplicitConversions(S, cast<Expr>(*I)); 2754} 2755 2756} // end anonymous namespace 2757 2758/// Diagnoses "dangerous" implicit conversions within the given 2759/// expression (which is a full expression). Implements -Wconversion 2760/// and -Wsign-compare. 2761void Sema::CheckImplicitConversions(Expr *E) { 2762 // Don't diagnose in unevaluated contexts. 2763 if (ExprEvalContexts.back().Context == Sema::Unevaluated) 2764 return; 2765 2766 // Don't diagnose for value- or type-dependent expressions. 2767 if (E->isTypeDependent() || E->isValueDependent()) 2768 return; 2769 2770 AnalyzeImplicitConversions(*this, E); 2771} 2772 2773/// CheckParmsForFunctionDef - Check that the parameters of the given 2774/// function are appropriate for the definition of a function. This 2775/// takes care of any checks that cannot be performed on the 2776/// declaration itself, e.g., that the types of each of the function 2777/// parameters are complete. 2778bool Sema::CheckParmsForFunctionDef(FunctionDecl *FD) { 2779 bool HasInvalidParm = false; 2780 for (unsigned p = 0, NumParams = FD->getNumParams(); p < NumParams; ++p) { 2781 ParmVarDecl *Param = FD->getParamDecl(p); 2782 2783 // C99 6.7.5.3p4: the parameters in a parameter type list in a 2784 // function declarator that is part of a function definition of 2785 // that function shall not have incomplete type. 2786 // 2787 // This is also C++ [dcl.fct]p6. 2788 if (!Param->isInvalidDecl() && 2789 RequireCompleteType(Param->getLocation(), Param->getType(), 2790 diag::err_typecheck_decl_incomplete_type)) { 2791 Param->setInvalidDecl(); 2792 HasInvalidParm = true; 2793 } 2794 2795 // C99 6.9.1p5: If the declarator includes a parameter type list, the 2796 // declaration of each parameter shall include an identifier. 2797 if (Param->getIdentifier() == 0 && 2798 !Param->isImplicit() && 2799 !getLangOptions().CPlusPlus) 2800 Diag(Param->getLocation(), diag::err_parameter_name_omitted); 2801 2802 // C99 6.7.5.3p12: 2803 // If the function declarator is not part of a definition of that 2804 // function, parameters may have incomplete type and may use the [*] 2805 // notation in their sequences of declarator specifiers to specify 2806 // variable length array types. 2807 QualType PType = Param->getOriginalType(); 2808 if (const ArrayType *AT = Context.getAsArrayType(PType)) { 2809 if (AT->getSizeModifier() == ArrayType::Star) { 2810 // FIXME: This diagnosic should point the the '[*]' if source-location 2811 // information is added for it. 2812 Diag(Param->getLocation(), diag::err_array_star_in_function_definition); 2813 } 2814 } 2815 } 2816 2817 return HasInvalidParm; 2818} 2819 2820/// CheckCastAlign - Implements -Wcast-align, which warns when a 2821/// pointer cast increases the alignment requirements. 2822void Sema::CheckCastAlign(Expr *Op, QualType T, SourceRange TRange) { 2823 // This is actually a lot of work to potentially be doing on every 2824 // cast; don't do it if we're ignoring -Wcast_align (as is the default). 2825 if (getDiagnostics().getDiagnosticLevel(diag::warn_cast_align) 2826 == Diagnostic::Ignored) 2827 return; 2828 2829 // Ignore dependent types. 2830 if (T->isDependentType() || Op->getType()->isDependentType()) 2831 return; 2832 2833 // Require that the destination be a pointer type. 2834 const PointerType *DestPtr = T->getAs<PointerType>(); 2835 if (!DestPtr) return; 2836 2837 // If the destination has alignment 1, we're done. 2838 QualType DestPointee = DestPtr->getPointeeType(); 2839 if (DestPointee->isIncompleteType()) return; 2840 CharUnits DestAlign = Context.getTypeAlignInChars(DestPointee); 2841 if (DestAlign.isOne()) return; 2842 2843 // Require that the source be a pointer type. 2844 const PointerType *SrcPtr = Op->getType()->getAs<PointerType>(); 2845 if (!SrcPtr) return; 2846 QualType SrcPointee = SrcPtr->getPointeeType(); 2847 2848 // Whitelist casts from cv void*. We already implicitly 2849 // whitelisted casts to cv void*, since they have alignment 1. 2850 // Also whitelist casts involving incomplete types, which implicitly 2851 // includes 'void'. 2852 if (SrcPointee->isIncompleteType()) return; 2853 2854 CharUnits SrcAlign = Context.getTypeAlignInChars(SrcPointee); 2855 if (SrcAlign >= DestAlign) return; 2856 2857 Diag(TRange.getBegin(), diag::warn_cast_align) 2858 << Op->getType() << T 2859 << static_cast<unsigned>(SrcAlign.getQuantity()) 2860 << static_cast<unsigned>(DestAlign.getQuantity()) 2861 << TRange << Op->getSourceRange(); 2862} 2863 2864