1 //===--- SemaChecking.cpp - Extra Semantic Checking -----------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements extra semantic analysis beyond what is enforced
11 // by the C type system.
13 //===----------------------------------------------------------------------===//
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"
36 using namespace clang;
39 /// getLocationOfStringLiteralByte - Return a source location that points to the
40 /// specified byte of the specified string literal.
42 /// Strings are amazingly complex. They can be formed from multiple tokens and
43 /// can have escape sequences in them in addition to the usual trigraph and
44 /// escaped newline business. This routine handles this complexity.
46 SourceLocation Sema::getLocationOfStringLiteralByte(const StringLiteral *SL,
47 unsigned ByteNo) const {
48 assert(!SL->isWide() && "This doesn't work for wide strings yet");
50 // Loop over all of the tokens in this string until we find the one that
51 // contains the byte we're looking for.
54 assert(TokNo < SL->getNumConcatenated() && "Invalid byte number!");
55 SourceLocation StrTokLoc = SL->getStrTokenLoc(TokNo);
57 // Get the spelling of the string so that we can get the data that makes up
58 // the string literal, not the identifier for the macro it is potentially
60 SourceLocation StrTokSpellingLoc = SourceMgr.getSpellingLoc(StrTokLoc);
62 // Re-lex the token to get its length and original spelling.
63 std::pair<FileID, unsigned> LocInfo =
64 SourceMgr.getDecomposedLoc(StrTokSpellingLoc);
66 llvm::StringRef Buffer = SourceMgr.getBufferData(LocInfo.first, &Invalid);
68 return StrTokSpellingLoc;
70 const char *StrData = Buffer.data()+LocInfo.second;
72 // Create a langops struct and enable trigraphs. This is sufficient for
75 LangOpts.Trigraphs = true;
77 // Create a lexer starting at the beginning of this token.
78 Lexer TheLexer(StrTokSpellingLoc, LangOpts, Buffer.begin(), StrData,
81 TheLexer.LexFromRawLexer(TheTok);
83 // Use the StringLiteralParser to compute the length of the string in bytes.
84 StringLiteralParser SLP(&TheTok, 1, PP, /*Complain=*/false);
85 unsigned TokNumBytes = SLP.GetStringLength();
87 // If the byte is in this token, return the location of the byte.
88 if (ByteNo < TokNumBytes ||
89 (ByteNo == TokNumBytes && TokNo == SL->getNumConcatenated())) {
91 StringLiteralParser::getOffsetOfStringByte(TheTok, ByteNo, PP,
94 // Now that we know the offset of the token in the spelling, use the
95 // preprocessor to get the offset in the original source.
96 return PP.AdvanceToTokenCharacter(StrTokLoc, Offset);
99 // Move to the next string token.
101 ByteNo -= TokNumBytes;
105 /// CheckablePrintfAttr - does a function call have a "printf" attribute
106 /// and arguments that merit checking?
107 bool Sema::CheckablePrintfAttr(const FormatAttr *Format, CallExpr *TheCall) {
108 if (Format->getType() == "printf") return true;
109 if (Format->getType() == "printf0") {
110 // printf0 allows null "format" string; if so don't check format/args
111 unsigned format_idx = Format->getFormatIdx() - 1;
112 // Does the index refer to the implicit object argument?
113 if (isa<CXXMemberCallExpr>(TheCall)) {
118 if (format_idx < TheCall->getNumArgs()) {
119 Expr *Format = TheCall->getArg(format_idx)->IgnoreParenCasts();
120 if (!Format->isNullPointerConstant(Context,
121 Expr::NPC_ValueDependentIsNull))
129 Sema::CheckBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) {
130 ExprResult TheCallResult(Owned(TheCall));
133 case Builtin::BI__builtin___CFStringMakeConstantString:
134 assert(TheCall->getNumArgs() == 1 &&
135 "Wrong # arguments to builtin CFStringMakeConstantString");
136 if (CheckObjCString(TheCall->getArg(0)))
139 case Builtin::BI__builtin_stdarg_start:
140 case Builtin::BI__builtin_va_start:
141 if (SemaBuiltinVAStart(TheCall))
144 case Builtin::BI__builtin_isgreater:
145 case Builtin::BI__builtin_isgreaterequal:
146 case Builtin::BI__builtin_isless:
147 case Builtin::BI__builtin_islessequal:
148 case Builtin::BI__builtin_islessgreater:
149 case Builtin::BI__builtin_isunordered:
150 if (SemaBuiltinUnorderedCompare(TheCall))
153 case Builtin::BI__builtin_fpclassify:
154 if (SemaBuiltinFPClassification(TheCall, 6))
157 case Builtin::BI__builtin_isfinite:
158 case Builtin::BI__builtin_isinf:
159 case Builtin::BI__builtin_isinf_sign:
160 case Builtin::BI__builtin_isnan:
161 case Builtin::BI__builtin_isnormal:
162 if (SemaBuiltinFPClassification(TheCall, 1))
165 case Builtin::BI__builtin_return_address:
166 case Builtin::BI__builtin_frame_address: {
168 if (SemaBuiltinConstantArg(TheCall, 0, Result))
172 case Builtin::BI__builtin_eh_return_data_regno: {
174 if (SemaBuiltinConstantArg(TheCall, 0, Result))
178 case Builtin::BI__builtin_shufflevector:
179 return SemaBuiltinShuffleVector(TheCall);
180 // TheCall will be freed by the smart pointer here, but that's fine, since
181 // SemaBuiltinShuffleVector guts it, but then doesn't release it.
182 case Builtin::BI__builtin_prefetch:
183 if (SemaBuiltinPrefetch(TheCall))
186 case Builtin::BI__builtin_object_size:
187 if (SemaBuiltinObjectSize(TheCall))
190 case Builtin::BI__builtin_longjmp:
191 if (SemaBuiltinLongjmp(TheCall))
194 case Builtin::BI__sync_fetch_and_add:
195 case Builtin::BI__sync_fetch_and_sub:
196 case Builtin::BI__sync_fetch_and_or:
197 case Builtin::BI__sync_fetch_and_and:
198 case Builtin::BI__sync_fetch_and_xor:
199 case Builtin::BI__sync_add_and_fetch:
200 case Builtin::BI__sync_sub_and_fetch:
201 case Builtin::BI__sync_and_and_fetch:
202 case Builtin::BI__sync_or_and_fetch:
203 case Builtin::BI__sync_xor_and_fetch:
204 case Builtin::BI__sync_val_compare_and_swap:
205 case Builtin::BI__sync_bool_compare_and_swap:
206 case Builtin::BI__sync_lock_test_and_set:
207 case Builtin::BI__sync_lock_release:
208 return SemaBuiltinAtomicOverloaded(move(TheCallResult));
211 // Since the target specific builtins for each arch overlap, only check those
212 // of the arch we are compiling for.
213 if (BuiltinID >= Builtin::FirstTSBuiltin) {
214 switch (Context.Target.getTriple().getArch()) {
215 case llvm::Triple::arm:
216 case llvm::Triple::thumb:
217 if (CheckARMBuiltinFunctionCall(BuiltinID, TheCall))
220 case llvm::Triple::x86:
221 case llvm::Triple::x86_64:
222 if (CheckX86BuiltinFunctionCall(BuiltinID, TheCall))
230 return move(TheCallResult);
233 bool Sema::CheckX86BuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) {
235 case X86::BI__builtin_ia32_palignr128:
236 case X86::BI__builtin_ia32_palignr: {
238 if (SemaBuiltinConstantArg(TheCall, 2, Result))
246 // Get the valid immediate range for the specified NEON type code.
247 static unsigned RFT(unsigned t, bool shift = false) {
248 bool quad = t & 0x10;
252 return shift ? 7 : (8 << (int)quad) - 1;
254 return shift ? 15 : (4 << (int)quad) - 1;
256 return shift ? 31 : (2 << (int)quad) - 1;
258 return shift ? 63 : (1 << (int)quad) - 1;
260 assert(!shift && "cannot shift float types!");
261 return (2 << (int)quad) - 1;
263 assert(!shift && "cannot shift polynomial types!");
264 return (8 << (int)quad) - 1;
266 assert(!shift && "cannot shift polynomial types!");
267 return (4 << (int)quad) - 1;
269 assert(!shift && "cannot shift float types!");
270 return (4 << (int)quad) - 1;
275 bool Sema::CheckARMBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) {
281 #define GET_NEON_OVERLOAD_CHECK
282 #include "clang/Basic/arm_neon.inc"
283 #undef GET_NEON_OVERLOAD_CHECK
286 // For NEON intrinsics which are overloaded on vector element type, validate
287 // the immediate which specifies which variant to emit.
289 unsigned ArgNo = TheCall->getNumArgs()-1;
290 if (SemaBuiltinConstantArg(TheCall, ArgNo, Result))
293 TV = Result.getLimitedValue(32);
294 if ((TV > 31) || (mask & (1 << TV)) == 0)
295 return Diag(TheCall->getLocStart(), diag::err_invalid_neon_type_code)
296 << TheCall->getArg(ArgNo)->getSourceRange();
299 // For NEON intrinsics which take an immediate value as part of the
300 // instruction, range check them here.
301 unsigned i = 0, l = 0, u = 0;
303 default: return false;
304 case ARM::BI__builtin_arm_ssat: i = 1; l = 1; u = 31; break;
305 case ARM::BI__builtin_arm_usat: i = 1; u = 31; break;
306 case ARM::BI__builtin_arm_vcvtr_f:
307 case ARM::BI__builtin_arm_vcvtr_d: i = 1; u = 1; break;
308 #define GET_NEON_IMMEDIATE_CHECK
309 #include "clang/Basic/arm_neon.inc"
310 #undef GET_NEON_IMMEDIATE_CHECK
313 // Check that the immediate argument is actually a constant.
314 if (SemaBuiltinConstantArg(TheCall, i, Result))
317 // Range check against the upper/lower values for this isntruction.
318 unsigned Val = Result.getZExtValue();
319 if (Val < l || Val > (u + l))
320 return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range)
321 << l << u+l << TheCall->getArg(i)->getSourceRange();
323 // FIXME: VFP Intrinsics should error if VFP not present.
327 /// CheckFunctionCall - Check a direct function call for various correctness
328 /// and safety properties not strictly enforced by the C type system.
329 bool Sema::CheckFunctionCall(FunctionDecl *FDecl, CallExpr *TheCall) {
330 // Get the IdentifierInfo* for the called function.
331 IdentifierInfo *FnInfo = FDecl->getIdentifier();
333 // None of the checks below are needed for functions that don't have
334 // simple names (e.g., C++ conversion functions).
338 // FIXME: This mechanism should be abstracted to be less fragile and
339 // more efficient. For example, just map function ids to custom
343 if (const FormatAttr *Format = FDecl->getAttr<FormatAttr>()) {
344 const bool b = Format->getType() == "scanf";
345 if (b || CheckablePrintfAttr(Format, TheCall)) {
346 bool HasVAListArg = Format->getFirstArg() == 0;
347 CheckPrintfScanfArguments(TheCall, HasVAListArg,
348 Format->getFormatIdx() - 1,
349 HasVAListArg ? 0 : Format->getFirstArg() - 1,
354 specific_attr_iterator<NonNullAttr>
355 i = FDecl->specific_attr_begin<NonNullAttr>(),
356 e = FDecl->specific_attr_end<NonNullAttr>();
359 CheckNonNullArguments(*i, TheCall);
364 bool Sema::CheckBlockCall(NamedDecl *NDecl, CallExpr *TheCall) {
366 const FormatAttr *Format = NDecl->getAttr<FormatAttr>();
370 const VarDecl *V = dyn_cast<VarDecl>(NDecl);
374 QualType Ty = V->getType();
375 if (!Ty->isBlockPointerType())
378 const bool b = Format->getType() == "scanf";
379 if (!b && !CheckablePrintfAttr(Format, TheCall))
382 bool HasVAListArg = Format->getFirstArg() == 0;
383 CheckPrintfScanfArguments(TheCall, HasVAListArg, Format->getFormatIdx() - 1,
384 HasVAListArg ? 0 : Format->getFirstArg() - 1, !b);
389 /// SemaBuiltinAtomicOverloaded - We have a call to a function like
390 /// __sync_fetch_and_add, which is an overloaded function based on the pointer
391 /// type of its first argument. The main ActOnCallExpr routines have already
392 /// promoted the types of arguments because all of these calls are prototyped as
395 /// This function goes through and does final semantic checking for these
398 Sema::SemaBuiltinAtomicOverloaded(ExprResult TheCallResult) {
399 CallExpr *TheCall = (CallExpr *)TheCallResult.get();
400 DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts());
401 FunctionDecl *FDecl = cast<FunctionDecl>(DRE->getDecl());
403 // Ensure that we have at least one argument to do type inference from.
404 if (TheCall->getNumArgs() < 1) {
405 Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args_at_least)
406 << 0 << 1 << TheCall->getNumArgs()
407 << TheCall->getCallee()->getSourceRange();
411 // Inspect the first argument of the atomic builtin. This should always be
412 // a pointer type, whose element is an integral scalar or pointer type.
413 // Because it is a pointer type, we don't have to worry about any implicit
415 // FIXME: We don't allow floating point scalars as input.
416 Expr *FirstArg = TheCall->getArg(0);
417 if (!FirstArg->getType()->isPointerType()) {
418 Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer)
419 << FirstArg->getType() << FirstArg->getSourceRange();
424 FirstArg->getType()->getAs<PointerType>()->getPointeeType();
425 if (!ValType->isIntegerType() && !ValType->isPointerType() &&
426 !ValType->isBlockPointerType()) {
427 Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer_intptr)
428 << FirstArg->getType() << FirstArg->getSourceRange();
432 // The majority of builtins return a value, but a few have special return
433 // types, so allow them to override appropriately below.
434 QualType ResultType = ValType;
436 // We need to figure out which concrete builtin this maps onto. For example,
437 // __sync_fetch_and_add with a 2 byte object turns into
438 // __sync_fetch_and_add_2.
439 #define BUILTIN_ROW(x) \
440 { Builtin::BI##x##_1, Builtin::BI##x##_2, Builtin::BI##x##_4, \
441 Builtin::BI##x##_8, Builtin::BI##x##_16 }
443 static const unsigned BuiltinIndices[][5] = {
444 BUILTIN_ROW(__sync_fetch_and_add),
445 BUILTIN_ROW(__sync_fetch_and_sub),
446 BUILTIN_ROW(__sync_fetch_and_or),
447 BUILTIN_ROW(__sync_fetch_and_and),
448 BUILTIN_ROW(__sync_fetch_and_xor),
450 BUILTIN_ROW(__sync_add_and_fetch),
451 BUILTIN_ROW(__sync_sub_and_fetch),
452 BUILTIN_ROW(__sync_and_and_fetch),
453 BUILTIN_ROW(__sync_or_and_fetch),
454 BUILTIN_ROW(__sync_xor_and_fetch),
456 BUILTIN_ROW(__sync_val_compare_and_swap),
457 BUILTIN_ROW(__sync_bool_compare_and_swap),
458 BUILTIN_ROW(__sync_lock_test_and_set),
459 BUILTIN_ROW(__sync_lock_release)
463 // Determine the index of the size.
465 switch (Context.getTypeSizeInChars(ValType).getQuantity()) {
466 case 1: SizeIndex = 0; break;
467 case 2: SizeIndex = 1; break;
468 case 4: SizeIndex = 2; break;
469 case 8: SizeIndex = 3; break;
470 case 16: SizeIndex = 4; break;
472 Diag(DRE->getLocStart(), diag::err_atomic_builtin_pointer_size)
473 << FirstArg->getType() << FirstArg->getSourceRange();
477 // Each of these builtins has one pointer argument, followed by some number of
478 // values (0, 1 or 2) followed by a potentially empty varags list of stuff
479 // that we ignore. Find out which row of BuiltinIndices to read from as well
480 // as the number of fixed args.
481 unsigned BuiltinID = FDecl->getBuiltinID();
482 unsigned BuiltinIndex, NumFixed = 1;
484 default: assert(0 && "Unknown overloaded atomic builtin!");
485 case Builtin::BI__sync_fetch_and_add: BuiltinIndex = 0; break;
486 case Builtin::BI__sync_fetch_and_sub: BuiltinIndex = 1; break;
487 case Builtin::BI__sync_fetch_and_or: BuiltinIndex = 2; break;
488 case Builtin::BI__sync_fetch_and_and: BuiltinIndex = 3; break;
489 case Builtin::BI__sync_fetch_and_xor: BuiltinIndex = 4; break;
491 case Builtin::BI__sync_add_and_fetch: BuiltinIndex = 5; break;
492 case Builtin::BI__sync_sub_and_fetch: BuiltinIndex = 6; break;
493 case Builtin::BI__sync_and_and_fetch: BuiltinIndex = 7; break;
494 case Builtin::BI__sync_or_and_fetch: BuiltinIndex = 8; break;
495 case Builtin::BI__sync_xor_and_fetch: BuiltinIndex = 9; break;
497 case Builtin::BI__sync_val_compare_and_swap:
501 case Builtin::BI__sync_bool_compare_and_swap:
504 ResultType = Context.BoolTy;
506 case Builtin::BI__sync_lock_test_and_set: BuiltinIndex = 12; break;
507 case Builtin::BI__sync_lock_release:
510 ResultType = Context.VoidTy;
514 // Now that we know how many fixed arguments we expect, first check that we
515 // have at least that many.
516 if (TheCall->getNumArgs() < 1+NumFixed) {
517 Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args_at_least)
518 << 0 << 1+NumFixed << TheCall->getNumArgs()
519 << TheCall->getCallee()->getSourceRange();
523 // Get the decl for the concrete builtin from this, we can tell what the
524 // concrete integer type we should convert to is.
525 unsigned NewBuiltinID = BuiltinIndices[BuiltinIndex][SizeIndex];
526 const char *NewBuiltinName = Context.BuiltinInfo.GetName(NewBuiltinID);
527 IdentifierInfo *NewBuiltinII = PP.getIdentifierInfo(NewBuiltinName);
528 FunctionDecl *NewBuiltinDecl =
529 cast<FunctionDecl>(LazilyCreateBuiltin(NewBuiltinII, NewBuiltinID,
530 TUScope, false, DRE->getLocStart()));
532 // The first argument --- the pointer --- has a fixed type; we
533 // deduce the types of the rest of the arguments accordingly. Walk
534 // the remaining arguments, converting them to the deduced value type.
535 for (unsigned i = 0; i != NumFixed; ++i) {
536 Expr *Arg = TheCall->getArg(i+1);
538 // If the argument is an implicit cast, then there was a promotion due to
539 // "...", just remove it now.
540 if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(Arg)) {
541 Arg = ICE->getSubExpr();
543 TheCall->setArg(i+1, Arg);
546 // GCC does an implicit conversion to the pointer or integer ValType. This
547 // can fail in some cases (1i -> int**), check for this error case now.
548 CastKind Kind = CK_Unknown;
549 CXXCastPath BasePath;
550 if (CheckCastTypes(Arg->getSourceRange(), ValType, Arg, Kind, BasePath))
553 // Okay, we have something that *can* be converted to the right type. Check
554 // to see if there is a potentially weird extension going on here. This can
555 // happen when you do an atomic operation on something like an char* and
556 // pass in 42. The 42 gets converted to char. This is even more strange
557 // for things like 45.123 -> char, etc.
558 // FIXME: Do this check.
559 ImpCastExprToType(Arg, ValType, Kind, VK_RValue, &BasePath);
560 TheCall->setArg(i+1, Arg);
563 // Switch the DeclRefExpr to refer to the new decl.
564 DRE->setDecl(NewBuiltinDecl);
565 DRE->setType(NewBuiltinDecl->getType());
567 // Set the callee in the CallExpr.
568 // FIXME: This leaks the original parens and implicit casts.
569 Expr *PromotedCall = DRE;
570 UsualUnaryConversions(PromotedCall);
571 TheCall->setCallee(PromotedCall);
573 // Change the result type of the call to match the original value type. This
574 // is arbitrary, but the codegen for these builtins ins design to handle it
576 TheCall->setType(ResultType);
578 return move(TheCallResult);
582 /// CheckObjCString - Checks that the argument to the builtin
583 /// CFString constructor is correct
584 /// FIXME: GCC currently emits the following warning:
585 /// "warning: input conversion stopped due to an input byte that does not
586 /// belong to the input codeset UTF-8"
587 /// Note: It might also make sense to do the UTF-16 conversion here (would
588 /// simplify the backend).
589 bool Sema::CheckObjCString(Expr *Arg) {
590 Arg = Arg->IgnoreParenCasts();
591 StringLiteral *Literal = dyn_cast<StringLiteral>(Arg);
593 if (!Literal || Literal->isWide()) {
594 Diag(Arg->getLocStart(), diag::err_cfstring_literal_not_string_constant)
595 << Arg->getSourceRange();
599 size_t NulPos = Literal->getString().find('\0');
600 if (NulPos != llvm::StringRef::npos) {
601 Diag(getLocationOfStringLiteralByte(Literal, NulPos),
602 diag::warn_cfstring_literal_contains_nul_character)
603 << Arg->getSourceRange();
609 /// SemaBuiltinVAStart - Check the arguments to __builtin_va_start for validity.
610 /// Emit an error and return true on failure, return false on success.
611 bool Sema::SemaBuiltinVAStart(CallExpr *TheCall) {
612 Expr *Fn = TheCall->getCallee();
613 if (TheCall->getNumArgs() > 2) {
614 Diag(TheCall->getArg(2)->getLocStart(),
615 diag::err_typecheck_call_too_many_args)
616 << 0 /*function call*/ << 2 << TheCall->getNumArgs()
617 << Fn->getSourceRange()
618 << SourceRange(TheCall->getArg(2)->getLocStart(),
619 (*(TheCall->arg_end()-1))->getLocEnd());
623 if (TheCall->getNumArgs() < 2) {
624 return Diag(TheCall->getLocEnd(),
625 diag::err_typecheck_call_too_few_args_at_least)
626 << 0 /*function call*/ << 2 << TheCall->getNumArgs();
629 // Determine whether the current function is variadic or not.
630 BlockScopeInfo *CurBlock = getCurBlock();
633 isVariadic = CurBlock->TheDecl->isVariadic();
634 else if (FunctionDecl *FD = getCurFunctionDecl())
635 isVariadic = FD->isVariadic();
637 isVariadic = getCurMethodDecl()->isVariadic();
640 Diag(Fn->getLocStart(), diag::err_va_start_used_in_non_variadic_function);
644 // Verify that the second argument to the builtin is the last argument of the
645 // current function or method.
646 bool SecondArgIsLastNamedArgument = false;
647 const Expr *Arg = TheCall->getArg(1)->IgnoreParenCasts();
649 if (const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(Arg)) {
650 if (const ParmVarDecl *PV = dyn_cast<ParmVarDecl>(DR->getDecl())) {
651 // FIXME: This isn't correct for methods (results in bogus warning).
652 // Get the last formal in the current function.
653 const ParmVarDecl *LastArg;
655 LastArg = *(CurBlock->TheDecl->param_end()-1);
656 else if (FunctionDecl *FD = getCurFunctionDecl())
657 LastArg = *(FD->param_end()-1);
659 LastArg = *(getCurMethodDecl()->param_end()-1);
660 SecondArgIsLastNamedArgument = PV == LastArg;
664 if (!SecondArgIsLastNamedArgument)
665 Diag(TheCall->getArg(1)->getLocStart(),
666 diag::warn_second_parameter_of_va_start_not_last_named_argument);
670 /// SemaBuiltinUnorderedCompare - Handle functions like __builtin_isgreater and
671 /// friends. This is declared to take (...), so we have to check everything.
672 bool Sema::SemaBuiltinUnorderedCompare(CallExpr *TheCall) {
673 if (TheCall->getNumArgs() < 2)
674 return Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args)
675 << 0 << 2 << TheCall->getNumArgs()/*function call*/;
676 if (TheCall->getNumArgs() > 2)
677 return Diag(TheCall->getArg(2)->getLocStart(),
678 diag::err_typecheck_call_too_many_args)
679 << 0 /*function call*/ << 2 << TheCall->getNumArgs()
680 << SourceRange(TheCall->getArg(2)->getLocStart(),
681 (*(TheCall->arg_end()-1))->getLocEnd());
683 Expr *OrigArg0 = TheCall->getArg(0);
684 Expr *OrigArg1 = TheCall->getArg(1);
686 // Do standard promotions between the two arguments, returning their common
688 QualType Res = UsualArithmeticConversions(OrigArg0, OrigArg1, false);
690 // Make sure any conversions are pushed back into the call; this is
691 // type safe since unordered compare builtins are declared as "_Bool
693 TheCall->setArg(0, OrigArg0);
694 TheCall->setArg(1, OrigArg1);
696 if (OrigArg0->isTypeDependent() || OrigArg1->isTypeDependent())
699 // If the common type isn't a real floating type, then the arguments were
700 // invalid for this operation.
701 if (!Res->isRealFloatingType())
702 return Diag(OrigArg0->getLocStart(),
703 diag::err_typecheck_call_invalid_ordered_compare)
704 << OrigArg0->getType() << OrigArg1->getType()
705 << SourceRange(OrigArg0->getLocStart(), OrigArg1->getLocEnd());
710 /// SemaBuiltinSemaBuiltinFPClassification - Handle functions like
711 /// __builtin_isnan and friends. This is declared to take (...), so we have
712 /// to check everything. We expect the last argument to be a floating point
714 bool Sema::SemaBuiltinFPClassification(CallExpr *TheCall, unsigned NumArgs) {
715 if (TheCall->getNumArgs() < NumArgs)
716 return Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args)
717 << 0 << NumArgs << TheCall->getNumArgs()/*function call*/;
718 if (TheCall->getNumArgs() > NumArgs)
719 return Diag(TheCall->getArg(NumArgs)->getLocStart(),
720 diag::err_typecheck_call_too_many_args)
721 << 0 /*function call*/ << NumArgs << TheCall->getNumArgs()
722 << SourceRange(TheCall->getArg(NumArgs)->getLocStart(),
723 (*(TheCall->arg_end()-1))->getLocEnd());
725 Expr *OrigArg = TheCall->getArg(NumArgs-1);
727 if (OrigArg->isTypeDependent())
730 // This operation requires a non-_Complex floating-point number.
731 if (!OrigArg->getType()->isRealFloatingType())
732 return Diag(OrigArg->getLocStart(),
733 diag::err_typecheck_call_invalid_unary_fp)
734 << OrigArg->getType() << OrigArg->getSourceRange();
736 // If this is an implicit conversion from float -> double, remove it.
737 if (ImplicitCastExpr *Cast = dyn_cast<ImplicitCastExpr>(OrigArg)) {
738 Expr *CastArg = Cast->getSubExpr();
739 if (CastArg->getType()->isSpecificBuiltinType(BuiltinType::Float)) {
740 assert(Cast->getType()->isSpecificBuiltinType(BuiltinType::Double) &&
741 "promotion from float to double is the only expected cast here");
743 TheCall->setArg(NumArgs-1, CastArg);
751 /// SemaBuiltinShuffleVector - Handle __builtin_shufflevector.
752 // This is declared to take (...), so we have to check everything.
753 ExprResult Sema::SemaBuiltinShuffleVector(CallExpr *TheCall) {
754 if (TheCall->getNumArgs() < 2)
755 return ExprError(Diag(TheCall->getLocEnd(),
756 diag::err_typecheck_call_too_few_args_at_least)
757 << 0 /*function call*/ << 2 << TheCall->getNumArgs()
758 << TheCall->getSourceRange());
760 // Determine which of the following types of shufflevector we're checking:
761 // 1) unary, vector mask: (lhs, mask)
762 // 2) binary, vector mask: (lhs, rhs, mask)
763 // 3) binary, scalar mask: (lhs, rhs, index, ..., index)
764 QualType resType = TheCall->getArg(0)->getType();
765 unsigned numElements = 0;
767 if (!TheCall->getArg(0)->isTypeDependent() &&
768 !TheCall->getArg(1)->isTypeDependent()) {
769 QualType LHSType = TheCall->getArg(0)->getType();
770 QualType RHSType = TheCall->getArg(1)->getType();
772 if (!LHSType->isVectorType() || !RHSType->isVectorType()) {
773 Diag(TheCall->getLocStart(), diag::err_shufflevector_non_vector)
774 << SourceRange(TheCall->getArg(0)->getLocStart(),
775 TheCall->getArg(1)->getLocEnd());
779 numElements = LHSType->getAs<VectorType>()->getNumElements();
780 unsigned numResElements = TheCall->getNumArgs() - 2;
782 // Check to see if we have a call with 2 vector arguments, the unary shuffle
783 // with mask. If so, verify that RHS is an integer vector type with the
784 // same number of elts as lhs.
785 if (TheCall->getNumArgs() == 2) {
786 if (!RHSType->hasIntegerRepresentation() ||
787 RHSType->getAs<VectorType>()->getNumElements() != numElements)
788 Diag(TheCall->getLocStart(), diag::err_shufflevector_incompatible_vector)
789 << SourceRange(TheCall->getArg(1)->getLocStart(),
790 TheCall->getArg(1)->getLocEnd());
791 numResElements = numElements;
793 else if (!Context.hasSameUnqualifiedType(LHSType, RHSType)) {
794 Diag(TheCall->getLocStart(), diag::err_shufflevector_incompatible_vector)
795 << SourceRange(TheCall->getArg(0)->getLocStart(),
796 TheCall->getArg(1)->getLocEnd());
798 } else if (numElements != numResElements) {
799 QualType eltType = LHSType->getAs<VectorType>()->getElementType();
800 resType = Context.getVectorType(eltType, numResElements,
801 VectorType::NotAltiVec);
805 for (unsigned i = 2; i < TheCall->getNumArgs(); i++) {
806 if (TheCall->getArg(i)->isTypeDependent() ||
807 TheCall->getArg(i)->isValueDependent())
810 llvm::APSInt Result(32);
811 if (!TheCall->getArg(i)->isIntegerConstantExpr(Result, Context))
812 return ExprError(Diag(TheCall->getLocStart(),
813 diag::err_shufflevector_nonconstant_argument)
814 << TheCall->getArg(i)->getSourceRange());
816 if (Result.getActiveBits() > 64 || Result.getZExtValue() >= numElements*2)
817 return ExprError(Diag(TheCall->getLocStart(),
818 diag::err_shufflevector_argument_too_large)
819 << TheCall->getArg(i)->getSourceRange());
822 llvm::SmallVector<Expr*, 32> exprs;
824 for (unsigned i = 0, e = TheCall->getNumArgs(); i != e; i++) {
825 exprs.push_back(TheCall->getArg(i));
826 TheCall->setArg(i, 0);
829 return Owned(new (Context) ShuffleVectorExpr(Context, exprs.begin(),
830 exprs.size(), resType,
831 TheCall->getCallee()->getLocStart(),
832 TheCall->getRParenLoc()));
835 /// SemaBuiltinPrefetch - Handle __builtin_prefetch.
836 // This is declared to take (const void*, ...) and can take two
837 // optional constant int args.
838 bool Sema::SemaBuiltinPrefetch(CallExpr *TheCall) {
839 unsigned NumArgs = TheCall->getNumArgs();
842 return Diag(TheCall->getLocEnd(),
843 diag::err_typecheck_call_too_many_args_at_most)
844 << 0 /*function call*/ << 3 << NumArgs
845 << TheCall->getSourceRange();
847 // Argument 0 is checked for us and the remaining arguments must be
848 // constant integers.
849 for (unsigned i = 1; i != NumArgs; ++i) {
850 Expr *Arg = TheCall->getArg(i);
853 if (SemaBuiltinConstantArg(TheCall, i, Result))
856 // FIXME: gcc issues a warning and rewrites these to 0. These
857 // seems especially odd for the third argument since the default
860 if (Result.getLimitedValue() > 1)
861 return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range)
862 << "0" << "1" << Arg->getSourceRange();
864 if (Result.getLimitedValue() > 3)
865 return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range)
866 << "0" << "3" << Arg->getSourceRange();
873 /// SemaBuiltinConstantArg - Handle a check if argument ArgNum of CallExpr
874 /// TheCall is a constant expression.
875 bool Sema::SemaBuiltinConstantArg(CallExpr *TheCall, int ArgNum,
876 llvm::APSInt &Result) {
877 Expr *Arg = TheCall->getArg(ArgNum);
878 DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts());
879 FunctionDecl *FDecl = cast<FunctionDecl>(DRE->getDecl());
881 if (Arg->isTypeDependent() || Arg->isValueDependent()) return false;
883 if (!Arg->isIntegerConstantExpr(Result, Context))
884 return Diag(TheCall->getLocStart(), diag::err_constant_integer_arg_type)
885 << FDecl->getDeclName() << Arg->getSourceRange();
890 /// SemaBuiltinObjectSize - Handle __builtin_object_size(void *ptr,
891 /// int type). This simply type checks that type is one of the defined
893 // For compatability check 0-3, llvm only handles 0 and 2.
894 bool Sema::SemaBuiltinObjectSize(CallExpr *TheCall) {
897 // Check constant-ness first.
898 if (SemaBuiltinConstantArg(TheCall, 1, Result))
901 Expr *Arg = TheCall->getArg(1);
902 if (Result.getSExtValue() < 0 || Result.getSExtValue() > 3) {
903 return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range)
904 << "0" << "3" << SourceRange(Arg->getLocStart(), Arg->getLocEnd());
910 /// SemaBuiltinLongjmp - Handle __builtin_longjmp(void *env[5], int val).
911 /// This checks that val is a constant 1.
912 bool Sema::SemaBuiltinLongjmp(CallExpr *TheCall) {
913 Expr *Arg = TheCall->getArg(1);
916 // TODO: This is less than ideal. Overload this to take a value.
917 if (SemaBuiltinConstantArg(TheCall, 1, Result))
921 return Diag(TheCall->getLocStart(), diag::err_builtin_longjmp_invalid_val)
922 << SourceRange(Arg->getLocStart(), Arg->getLocEnd());
927 // Handle i > 1 ? "x" : "y", recursivelly
928 bool Sema::SemaCheckStringLiteral(const Expr *E, const CallExpr *TheCall,
930 unsigned format_idx, unsigned firstDataArg,
933 if (E->isTypeDependent() || E->isValueDependent())
936 switch (E->getStmtClass()) {
937 case Stmt::ConditionalOperatorClass: {
938 const ConditionalOperator *C = cast<ConditionalOperator>(E);
939 return SemaCheckStringLiteral(C->getTrueExpr(), TheCall, HasVAListArg,
940 format_idx, firstDataArg, isPrintf)
941 && SemaCheckStringLiteral(C->getRHS(), TheCall, HasVAListArg,
942 format_idx, firstDataArg, isPrintf);
945 case Stmt::ImplicitCastExprClass: {
946 const ImplicitCastExpr *Expr = cast<ImplicitCastExpr>(E);
947 return SemaCheckStringLiteral(Expr->getSubExpr(), TheCall, HasVAListArg,
948 format_idx, firstDataArg, isPrintf);
951 case Stmt::ParenExprClass: {
952 const ParenExpr *Expr = cast<ParenExpr>(E);
953 return SemaCheckStringLiteral(Expr->getSubExpr(), TheCall, HasVAListArg,
954 format_idx, firstDataArg, isPrintf);
957 case Stmt::DeclRefExprClass: {
958 const DeclRefExpr *DR = cast<DeclRefExpr>(E);
960 // As an exception, do not flag errors for variables binding to
961 // const string literals.
962 if (const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl())) {
963 bool isConstant = false;
964 QualType T = DR->getType();
966 if (const ArrayType *AT = Context.getAsArrayType(T)) {
967 isConstant = AT->getElementType().isConstant(Context);
968 } else if (const PointerType *PT = T->getAs<PointerType>()) {
969 isConstant = T.isConstant(Context) &&
970 PT->getPointeeType().isConstant(Context);
974 if (const Expr *Init = VD->getAnyInitializer())
975 return SemaCheckStringLiteral(Init, TheCall,
976 HasVAListArg, format_idx, firstDataArg,
980 // For vprintf* functions (i.e., HasVAListArg==true), we add a
981 // special check to see if the format string is a function parameter
982 // of the function calling the printf function. If the function
983 // has an attribute indicating it is a printf-like function, then we
984 // should suppress warnings concerning non-literals being used in a call
985 // to a vprintf function. For example:
988 // logmessage(char const *fmt __attribute__ (format (printf, 1, 2)), ...){
990 // va_start(ap, fmt);
991 // vprintf(fmt, ap); // Do NOT emit a warning about "fmt".
995 // FIXME: We don't have full attribute support yet, so just check to see
996 // if the argument is a DeclRefExpr that references a parameter. We'll
997 // add proper support for checking the attribute later.
999 if (isa<ParmVarDecl>(VD))
1006 case Stmt::CallExprClass: {
1007 const CallExpr *CE = cast<CallExpr>(E);
1008 if (const ImplicitCastExpr *ICE
1009 = dyn_cast<ImplicitCastExpr>(CE->getCallee())) {
1010 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(ICE->getSubExpr())) {
1011 if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(DRE->getDecl())) {
1012 if (const FormatArgAttr *FA = FD->getAttr<FormatArgAttr>()) {
1013 unsigned ArgIndex = FA->getFormatIdx();
1014 const Expr *Arg = CE->getArg(ArgIndex - 1);
1016 return SemaCheckStringLiteral(Arg, TheCall, HasVAListArg,
1017 format_idx, firstDataArg, isPrintf);
1025 case Stmt::ObjCStringLiteralClass:
1026 case Stmt::StringLiteralClass: {
1027 const StringLiteral *StrE = NULL;
1029 if (const ObjCStringLiteral *ObjCFExpr = dyn_cast<ObjCStringLiteral>(E))
1030 StrE = ObjCFExpr->getString();
1032 StrE = cast<StringLiteral>(E);
1035 CheckFormatString(StrE, E, TheCall, HasVAListArg, format_idx,
1036 firstDataArg, isPrintf);
1049 Sema::CheckNonNullArguments(const NonNullAttr *NonNull,
1050 const CallExpr *TheCall) {
1051 for (NonNullAttr::args_iterator i = NonNull->args_begin(),
1052 e = NonNull->args_end();
1054 const Expr *ArgExpr = TheCall->getArg(*i);
1055 if (ArgExpr->isNullPointerConstant(Context,
1056 Expr::NPC_ValueDependentIsNotNull))
1057 Diag(TheCall->getCallee()->getLocStart(), diag::warn_null_arg)
1058 << ArgExpr->getSourceRange();
1062 /// CheckPrintfScanfArguments - Check calls to printf and scanf (and similar
1063 /// functions) for correct use of format strings.
1065 Sema::CheckPrintfScanfArguments(const CallExpr *TheCall, bool HasVAListArg,
1066 unsigned format_idx, unsigned firstDataArg,
1069 const Expr *Fn = TheCall->getCallee();
1071 // The way the format attribute works in GCC, the implicit this argument
1072 // of member functions is counted. However, it doesn't appear in our own
1073 // lists, so decrement format_idx in that case.
1074 if (isa<CXXMemberCallExpr>(TheCall)) {
1075 // Catch a format attribute mistakenly referring to the object argument.
1076 if (format_idx == 0)
1079 if(firstDataArg != 0)
1083 // CHECK: printf/scanf-like function is called with no format string.
1084 if (format_idx >= TheCall->getNumArgs()) {
1085 Diag(TheCall->getRParenLoc(), diag::warn_missing_format_string)
1086 << Fn->getSourceRange();
1090 const Expr *OrigFormatExpr = TheCall->getArg(format_idx)->IgnoreParenCasts();
1092 // CHECK: format string is not a string literal.
1094 // Dynamically generated format strings are difficult to
1095 // automatically vet at compile time. Requiring that format strings
1096 // are string literals: (1) permits the checking of format strings by
1097 // the compiler and thereby (2) can practically remove the source of
1098 // many format string exploits.
1100 // Format string can be either ObjC string (e.g. @"%d") or
1101 // C string (e.g. "%d")
1102 // ObjC string uses the same format specifiers as C string, so we can use
1103 // the same format string checking logic for both ObjC and C strings.
1104 if (SemaCheckStringLiteral(OrigFormatExpr, TheCall, HasVAListArg, format_idx,
1105 firstDataArg, isPrintf))
1106 return; // Literal format string found, check done!
1108 // If there are no arguments specified, warn with -Wformat-security, otherwise
1109 // warn only with -Wformat-nonliteral.
1110 if (TheCall->getNumArgs() == format_idx+1)
1111 Diag(TheCall->getArg(format_idx)->getLocStart(),
1112 diag::warn_format_nonliteral_noargs)
1113 << OrigFormatExpr->getSourceRange();
1115 Diag(TheCall->getArg(format_idx)->getLocStart(),
1116 diag::warn_format_nonliteral)
1117 << OrigFormatExpr->getSourceRange();
1121 class CheckFormatHandler : public analyze_format_string::FormatStringHandler {
1124 const StringLiteral *FExpr;
1125 const Expr *OrigFormatExpr;
1126 const unsigned FirstDataArg;
1127 const unsigned NumDataArgs;
1128 const bool IsObjCLiteral;
1129 const char *Beg; // Start of format string.
1130 const bool HasVAListArg;
1131 const CallExpr *TheCall;
1133 llvm::BitVector CoveredArgs;
1134 bool usesPositionalArgs;
1137 CheckFormatHandler(Sema &s, const StringLiteral *fexpr,
1138 const Expr *origFormatExpr, unsigned firstDataArg,
1139 unsigned numDataArgs, bool isObjCLiteral,
1140 const char *beg, bool hasVAListArg,
1141 const CallExpr *theCall, unsigned formatIdx)
1142 : S(s), FExpr(fexpr), OrigFormatExpr(origFormatExpr),
1143 FirstDataArg(firstDataArg),
1144 NumDataArgs(numDataArgs),
1145 IsObjCLiteral(isObjCLiteral), Beg(beg),
1146 HasVAListArg(hasVAListArg),
1147 TheCall(theCall), FormatIdx(formatIdx),
1148 usesPositionalArgs(false), atFirstArg(true) {
1149 CoveredArgs.resize(numDataArgs);
1150 CoveredArgs.reset();
1153 void DoneProcessing();
1155 void HandleIncompleteSpecifier(const char *startSpecifier,
1156 unsigned specifierLen);
1158 virtual void HandleInvalidPosition(const char *startSpecifier,
1159 unsigned specifierLen,
1160 analyze_format_string::PositionContext p);
1162 virtual void HandleZeroPosition(const char *startPos, unsigned posLen);
1164 void HandleNullChar(const char *nullCharacter);
1167 bool HandleInvalidConversionSpecifier(unsigned argIndex, SourceLocation Loc,
1168 const char *startSpec,
1169 unsigned specifierLen,
1170 const char *csStart, unsigned csLen);
1172 SourceRange getFormatStringRange();
1173 CharSourceRange getSpecifierRange(const char *startSpecifier,
1174 unsigned specifierLen);
1175 SourceLocation getLocationOfByte(const char *x);
1177 const Expr *getDataArg(unsigned i) const;
1179 bool CheckNumArgs(const analyze_format_string::FormatSpecifier &FS,
1180 const analyze_format_string::ConversionSpecifier &CS,
1181 const char *startSpecifier, unsigned specifierLen,
1186 SourceRange CheckFormatHandler::getFormatStringRange() {
1187 return OrigFormatExpr->getSourceRange();
1190 CharSourceRange CheckFormatHandler::
1191 getSpecifierRange(const char *startSpecifier, unsigned specifierLen) {
1192 SourceLocation Start = getLocationOfByte(startSpecifier);
1193 SourceLocation End = getLocationOfByte(startSpecifier + specifierLen - 1);
1195 // Advance the end SourceLocation by one due to half-open ranges.
1196 End = End.getFileLocWithOffset(1);
1198 return CharSourceRange::getCharRange(Start, End);
1201 SourceLocation CheckFormatHandler::getLocationOfByte(const char *x) {
1202 return S.getLocationOfStringLiteralByte(FExpr, x - Beg);
1205 void CheckFormatHandler::HandleIncompleteSpecifier(const char *startSpecifier,
1206 unsigned specifierLen){
1207 SourceLocation Loc = getLocationOfByte(startSpecifier);
1208 S.Diag(Loc, diag::warn_printf_incomplete_specifier)
1209 << getSpecifierRange(startSpecifier, specifierLen);
1213 CheckFormatHandler::HandleInvalidPosition(const char *startPos, unsigned posLen,
1214 analyze_format_string::PositionContext p) {
1215 SourceLocation Loc = getLocationOfByte(startPos);
1216 S.Diag(Loc, diag::warn_format_invalid_positional_specifier)
1217 << (unsigned) p << getSpecifierRange(startPos, posLen);
1220 void CheckFormatHandler::HandleZeroPosition(const char *startPos,
1222 SourceLocation Loc = getLocationOfByte(startPos);
1223 S.Diag(Loc, diag::warn_format_zero_positional_specifier)
1224 << getSpecifierRange(startPos, posLen);
1227 void CheckFormatHandler::HandleNullChar(const char *nullCharacter) {
1228 // The presence of a null character is likely an error.
1229 S.Diag(getLocationOfByte(nullCharacter),
1230 diag::warn_printf_format_string_contains_null_char)
1231 << getFormatStringRange();
1234 const Expr *CheckFormatHandler::getDataArg(unsigned i) const {
1235 return TheCall->getArg(FirstDataArg + i);
1238 void CheckFormatHandler::DoneProcessing() {
1239 // Does the number of data arguments exceed the number of
1240 // format conversions in the format string?
1241 if (!HasVAListArg) {
1242 // Find any arguments that weren't covered.
1244 signed notCoveredArg = CoveredArgs.find_first();
1245 if (notCoveredArg >= 0) {
1246 assert((unsigned)notCoveredArg < NumDataArgs);
1247 S.Diag(getDataArg((unsigned) notCoveredArg)->getLocStart(),
1248 diag::warn_printf_data_arg_not_used)
1249 << getFormatStringRange();
1255 CheckFormatHandler::HandleInvalidConversionSpecifier(unsigned argIndex,
1257 const char *startSpec,
1258 unsigned specifierLen,
1259 const char *csStart,
1262 bool keepGoing = true;
1263 if (argIndex < NumDataArgs) {
1264 // Consider the argument coverered, even though the specifier doesn't
1266 CoveredArgs.set(argIndex);
1269 // If argIndex exceeds the number of data arguments we
1270 // don't issue a warning because that is just a cascade of warnings (and
1271 // they may have intended '%%' anyway). We don't want to continue processing
1272 // the format string after this point, however, as we will like just get
1273 // gibberish when trying to match arguments.
1277 S.Diag(Loc, diag::warn_format_invalid_conversion)
1278 << llvm::StringRef(csStart, csLen)
1279 << getSpecifierRange(startSpec, specifierLen);
1285 CheckFormatHandler::CheckNumArgs(
1286 const analyze_format_string::FormatSpecifier &FS,
1287 const analyze_format_string::ConversionSpecifier &CS,
1288 const char *startSpecifier, unsigned specifierLen, unsigned argIndex) {
1290 if (argIndex >= NumDataArgs) {
1291 if (FS.usesPositionalArg()) {
1292 S.Diag(getLocationOfByte(CS.getStart()),
1293 diag::warn_printf_positional_arg_exceeds_data_args)
1294 << (argIndex+1) << NumDataArgs
1295 << getSpecifierRange(startSpecifier, specifierLen);
1298 S.Diag(getLocationOfByte(CS.getStart()),
1299 diag::warn_printf_insufficient_data_args)
1300 << getSpecifierRange(startSpecifier, specifierLen);
1308 //===--- CHECK: Printf format string checking ------------------------------===//
1311 class CheckPrintfHandler : public CheckFormatHandler {
1313 CheckPrintfHandler(Sema &s, const StringLiteral *fexpr,
1314 const Expr *origFormatExpr, unsigned firstDataArg,
1315 unsigned numDataArgs, bool isObjCLiteral,
1316 const char *beg, bool hasVAListArg,
1317 const CallExpr *theCall, unsigned formatIdx)
1318 : CheckFormatHandler(s, fexpr, origFormatExpr, firstDataArg,
1319 numDataArgs, isObjCLiteral, beg, hasVAListArg,
1320 theCall, formatIdx) {}
1323 bool HandleInvalidPrintfConversionSpecifier(
1324 const analyze_printf::PrintfSpecifier &FS,
1325 const char *startSpecifier,
1326 unsigned specifierLen);
1328 bool HandlePrintfSpecifier(const analyze_printf::PrintfSpecifier &FS,
1329 const char *startSpecifier,
1330 unsigned specifierLen);
1332 bool HandleAmount(const analyze_format_string::OptionalAmount &Amt, unsigned k,
1333 const char *startSpecifier, unsigned specifierLen);
1334 void HandleInvalidAmount(const analyze_printf::PrintfSpecifier &FS,
1335 const analyze_printf::OptionalAmount &Amt,
1337 const char *startSpecifier, unsigned specifierLen);
1338 void HandleFlag(const analyze_printf::PrintfSpecifier &FS,
1339 const analyze_printf::OptionalFlag &flag,
1340 const char *startSpecifier, unsigned specifierLen);
1341 void HandleIgnoredFlag(const analyze_printf::PrintfSpecifier &FS,
1342 const analyze_printf::OptionalFlag &ignoredFlag,
1343 const analyze_printf::OptionalFlag &flag,
1344 const char *startSpecifier, unsigned specifierLen);
1348 bool CheckPrintfHandler::HandleInvalidPrintfConversionSpecifier(
1349 const analyze_printf::PrintfSpecifier &FS,
1350 const char *startSpecifier,
1351 unsigned specifierLen) {
1352 const analyze_printf::PrintfConversionSpecifier &CS =
1353 FS.getConversionSpecifier();
1355 return HandleInvalidConversionSpecifier(FS.getArgIndex(),
1356 getLocationOfByte(CS.getStart()),
1357 startSpecifier, specifierLen,
1358 CS.getStart(), CS.getLength());
1361 bool CheckPrintfHandler::HandleAmount(
1362 const analyze_format_string::OptionalAmount &Amt,
1363 unsigned k, const char *startSpecifier,
1364 unsigned specifierLen) {
1366 if (Amt.hasDataArgument()) {
1367 if (!HasVAListArg) {
1368 unsigned argIndex = Amt.getArgIndex();
1369 if (argIndex >= NumDataArgs) {
1370 S.Diag(getLocationOfByte(Amt.getStart()),
1371 diag::warn_printf_asterisk_missing_arg)
1372 << k << getSpecifierRange(startSpecifier, specifierLen);
1373 // Don't do any more checking. We will just emit
1378 // Type check the data argument. It should be an 'int'.
1379 // Although not in conformance with C99, we also allow the argument to be
1380 // an 'unsigned int' as that is a reasonably safe case. GCC also
1381 // doesn't emit a warning for that case.
1382 CoveredArgs.set(argIndex);
1383 const Expr *Arg = getDataArg(argIndex);
1384 QualType T = Arg->getType();
1386 const analyze_printf::ArgTypeResult &ATR = Amt.getArgType(S.Context);
1387 assert(ATR.isValid());
1389 if (!ATR.matchesType(S.Context, T)) {
1390 S.Diag(getLocationOfByte(Amt.getStart()),
1391 diag::warn_printf_asterisk_wrong_type)
1393 << ATR.getRepresentativeType(S.Context) << T
1394 << getSpecifierRange(startSpecifier, specifierLen)
1395 << Arg->getSourceRange();
1396 // Don't do any more checking. We will just emit
1405 void CheckPrintfHandler::HandleInvalidAmount(
1406 const analyze_printf::PrintfSpecifier &FS,
1407 const analyze_printf::OptionalAmount &Amt,
1409 const char *startSpecifier,
1410 unsigned specifierLen) {
1411 const analyze_printf::PrintfConversionSpecifier &CS =
1412 FS.getConversionSpecifier();
1413 switch (Amt.getHowSpecified()) {
1414 case analyze_printf::OptionalAmount::Constant:
1415 S.Diag(getLocationOfByte(Amt.getStart()),
1416 diag::warn_printf_nonsensical_optional_amount)
1419 << getSpecifierRange(startSpecifier, specifierLen)
1420 << FixItHint::CreateRemoval(getSpecifierRange(Amt.getStart(),
1421 Amt.getConstantLength()));
1425 S.Diag(getLocationOfByte(Amt.getStart()),
1426 diag::warn_printf_nonsensical_optional_amount)
1429 << getSpecifierRange(startSpecifier, specifierLen);
1434 void CheckPrintfHandler::HandleFlag(const analyze_printf::PrintfSpecifier &FS,
1435 const analyze_printf::OptionalFlag &flag,
1436 const char *startSpecifier,
1437 unsigned specifierLen) {
1438 // Warn about pointless flag with a fixit removal.
1439 const analyze_printf::PrintfConversionSpecifier &CS =
1440 FS.getConversionSpecifier();
1441 S.Diag(getLocationOfByte(flag.getPosition()),
1442 diag::warn_printf_nonsensical_flag)
1443 << flag.toString() << CS.toString()
1444 << getSpecifierRange(startSpecifier, specifierLen)
1445 << FixItHint::CreateRemoval(getSpecifierRange(flag.getPosition(), 1));
1448 void CheckPrintfHandler::HandleIgnoredFlag(
1449 const analyze_printf::PrintfSpecifier &FS,
1450 const analyze_printf::OptionalFlag &ignoredFlag,
1451 const analyze_printf::OptionalFlag &flag,
1452 const char *startSpecifier,
1453 unsigned specifierLen) {
1454 // Warn about ignored flag with a fixit removal.
1455 S.Diag(getLocationOfByte(ignoredFlag.getPosition()),
1456 diag::warn_printf_ignored_flag)
1457 << ignoredFlag.toString() << flag.toString()
1458 << getSpecifierRange(startSpecifier, specifierLen)
1459 << FixItHint::CreateRemoval(getSpecifierRange(
1460 ignoredFlag.getPosition(), 1));
1464 CheckPrintfHandler::HandlePrintfSpecifier(const analyze_printf::PrintfSpecifier
1466 const char *startSpecifier,
1467 unsigned specifierLen) {
1469 using namespace analyze_format_string;
1470 using namespace analyze_printf;
1471 const PrintfConversionSpecifier &CS = FS.getConversionSpecifier();
1473 if (FS.consumesDataArgument()) {
1476 usesPositionalArgs = FS.usesPositionalArg();
1478 else if (usesPositionalArgs != FS.usesPositionalArg()) {
1479 // Cannot mix-and-match positional and non-positional arguments.
1480 S.Diag(getLocationOfByte(CS.getStart()),
1481 diag::warn_format_mix_positional_nonpositional_args)
1482 << getSpecifierRange(startSpecifier, specifierLen);
1487 // First check if the field width, precision, and conversion specifier
1488 // have matching data arguments.
1489 if (!HandleAmount(FS.getFieldWidth(), /* field width */ 0,
1490 startSpecifier, specifierLen)) {
1494 if (!HandleAmount(FS.getPrecision(), /* precision */ 1,
1495 startSpecifier, specifierLen)) {
1499 if (!CS.consumesDataArgument()) {
1500 // FIXME: Technically specifying a precision or field width here
1501 // makes no sense. Worth issuing a warning at some point.
1505 // Consume the argument.
1506 unsigned argIndex = FS.getArgIndex();
1507 if (argIndex < NumDataArgs) {
1508 // The check to see if the argIndex is valid will come later.
1509 // We set the bit here because we may exit early from this
1510 // function if we encounter some other error.
1511 CoveredArgs.set(argIndex);
1514 // Check for using an Objective-C specific conversion specifier
1515 // in a non-ObjC literal.
1516 if (!IsObjCLiteral && CS.isObjCArg()) {
1517 return HandleInvalidPrintfConversionSpecifier(FS, startSpecifier,
1521 // Check for invalid use of field width
1522 if (!FS.hasValidFieldWidth()) {
1523 HandleInvalidAmount(FS, FS.getFieldWidth(), /* field width */ 0,
1524 startSpecifier, specifierLen);
1527 // Check for invalid use of precision
1528 if (!FS.hasValidPrecision()) {
1529 HandleInvalidAmount(FS, FS.getPrecision(), /* precision */ 1,
1530 startSpecifier, specifierLen);
1533 // Check each flag does not conflict with any other component.
1534 if (!FS.hasValidLeadingZeros())
1535 HandleFlag(FS, FS.hasLeadingZeros(), startSpecifier, specifierLen);
1536 if (!FS.hasValidPlusPrefix())
1537 HandleFlag(FS, FS.hasPlusPrefix(), startSpecifier, specifierLen);
1538 if (!FS.hasValidSpacePrefix())
1539 HandleFlag(FS, FS.hasSpacePrefix(), startSpecifier, specifierLen);
1540 if (!FS.hasValidAlternativeForm())
1541 HandleFlag(FS, FS.hasAlternativeForm(), startSpecifier, specifierLen);
1542 if (!FS.hasValidLeftJustified())
1543 HandleFlag(FS, FS.isLeftJustified(), startSpecifier, specifierLen);
1545 // Check that flags are not ignored by another flag
1546 if (FS.hasSpacePrefix() && FS.hasPlusPrefix()) // ' ' ignored by '+'
1547 HandleIgnoredFlag(FS, FS.hasSpacePrefix(), FS.hasPlusPrefix(),
1548 startSpecifier, specifierLen);
1549 if (FS.hasLeadingZeros() && FS.isLeftJustified()) // '0' ignored by '-'
1550 HandleIgnoredFlag(FS, FS.hasLeadingZeros(), FS.isLeftJustified(),
1551 startSpecifier, specifierLen);
1553 // Check the length modifier is valid with the given conversion specifier.
1554 const LengthModifier &LM = FS.getLengthModifier();
1555 if (!FS.hasValidLengthModifier())
1556 S.Diag(getLocationOfByte(LM.getStart()),
1557 diag::warn_format_nonsensical_length)
1558 << LM.toString() << CS.toString()
1559 << getSpecifierRange(startSpecifier, specifierLen)
1560 << FixItHint::CreateRemoval(getSpecifierRange(LM.getStart(),
1563 // Are we using '%n'?
1564 if (CS.getKind() == ConversionSpecifier::nArg) {
1565 // Issue a warning about this being a possible security issue.
1566 S.Diag(getLocationOfByte(CS.getStart()), diag::warn_printf_write_back)
1567 << getSpecifierRange(startSpecifier, specifierLen);
1568 // Continue checking the other format specifiers.
1572 // The remaining checks depend on the data arguments.
1576 if (!CheckNumArgs(FS, CS, startSpecifier, specifierLen, argIndex))
1579 // Now type check the data expression that matches the
1580 // format specifier.
1581 const Expr *Ex = getDataArg(argIndex);
1582 const analyze_printf::ArgTypeResult &ATR = FS.getArgType(S.Context);
1583 if (ATR.isValid() && !ATR.matchesType(S.Context, Ex->getType())) {
1584 // Check if we didn't match because of an implicit cast from a 'char'
1585 // or 'short' to an 'int'. This is done because printf is a varargs
1587 if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(Ex))
1588 if (ICE->getType() == S.Context.IntTy)
1589 if (ATR.matchesType(S.Context, ICE->getSubExpr()->getType()))
1592 // We may be able to offer a FixItHint if it is a supported type.
1593 PrintfSpecifier fixedFS = FS;
1594 bool success = fixedFS.fixType(Ex->getType());
1597 // Get the fix string from the fixed format specifier
1598 llvm::SmallString<128> buf;
1599 llvm::raw_svector_ostream os(buf);
1600 fixedFS.toString(os);
1602 // FIXME: getRepresentativeType() perhaps should return a string
1603 // instead of a QualType to better handle when the representative
1604 // type is 'wint_t' (which is defined in the system headers).
1605 S.Diag(getLocationOfByte(CS.getStart()),
1606 diag::warn_printf_conversion_argument_type_mismatch)
1607 << ATR.getRepresentativeType(S.Context) << Ex->getType()
1608 << getSpecifierRange(startSpecifier, specifierLen)
1609 << Ex->getSourceRange()
1610 << FixItHint::CreateReplacement(
1611 getSpecifierRange(startSpecifier, specifierLen),
1615 S.Diag(getLocationOfByte(CS.getStart()),
1616 diag::warn_printf_conversion_argument_type_mismatch)
1617 << ATR.getRepresentativeType(S.Context) << Ex->getType()
1618 << getSpecifierRange(startSpecifier, specifierLen)
1619 << Ex->getSourceRange();
1626 //===--- CHECK: Scanf format string checking ------------------------------===//
1629 class CheckScanfHandler : public CheckFormatHandler {
1631 CheckScanfHandler(Sema &s, const StringLiteral *fexpr,
1632 const Expr *origFormatExpr, unsigned firstDataArg,
1633 unsigned numDataArgs, bool isObjCLiteral,
1634 const char *beg, bool hasVAListArg,
1635 const CallExpr *theCall, unsigned formatIdx)
1636 : CheckFormatHandler(s, fexpr, origFormatExpr, firstDataArg,
1637 numDataArgs, isObjCLiteral, beg, hasVAListArg,
1638 theCall, formatIdx) {}
1640 bool HandleScanfSpecifier(const analyze_scanf::ScanfSpecifier &FS,
1641 const char *startSpecifier,
1642 unsigned specifierLen);
1644 bool HandleInvalidScanfConversionSpecifier(
1645 const analyze_scanf::ScanfSpecifier &FS,
1646 const char *startSpecifier,
1647 unsigned specifierLen);
1649 void HandleIncompleteScanList(const char *start, const char *end);
1653 void CheckScanfHandler::HandleIncompleteScanList(const char *start,
1655 S.Diag(getLocationOfByte(end), diag::warn_scanf_scanlist_incomplete)
1656 << getSpecifierRange(start, end - start);
1659 bool CheckScanfHandler::HandleInvalidScanfConversionSpecifier(
1660 const analyze_scanf::ScanfSpecifier &FS,
1661 const char *startSpecifier,
1662 unsigned specifierLen) {
1664 const analyze_scanf::ScanfConversionSpecifier &CS =
1665 FS.getConversionSpecifier();
1667 return HandleInvalidConversionSpecifier(FS.getArgIndex(),
1668 getLocationOfByte(CS.getStart()),
1669 startSpecifier, specifierLen,
1670 CS.getStart(), CS.getLength());
1673 bool CheckScanfHandler::HandleScanfSpecifier(
1674 const analyze_scanf::ScanfSpecifier &FS,
1675 const char *startSpecifier,
1676 unsigned specifierLen) {
1678 using namespace analyze_scanf;
1679 using namespace analyze_format_string;
1681 const ScanfConversionSpecifier &CS = FS.getConversionSpecifier();
1683 // Handle case where '%' and '*' don't consume an argument. These shouldn't
1684 // be used to decide if we are using positional arguments consistently.
1685 if (FS.consumesDataArgument()) {
1688 usesPositionalArgs = FS.usesPositionalArg();
1690 else if (usesPositionalArgs != FS.usesPositionalArg()) {
1691 // Cannot mix-and-match positional and non-positional arguments.
1692 S.Diag(getLocationOfByte(CS.getStart()),
1693 diag::warn_format_mix_positional_nonpositional_args)
1694 << getSpecifierRange(startSpecifier, specifierLen);
1699 // Check if the field with is non-zero.
1700 const OptionalAmount &Amt = FS.getFieldWidth();
1701 if (Amt.getHowSpecified() == OptionalAmount::Constant) {
1702 if (Amt.getConstantAmount() == 0) {
1703 const CharSourceRange &R = getSpecifierRange(Amt.getStart(),
1704 Amt.getConstantLength());
1705 S.Diag(getLocationOfByte(Amt.getStart()),
1706 diag::warn_scanf_nonzero_width)
1707 << R << FixItHint::CreateRemoval(R);
1711 if (!FS.consumesDataArgument()) {
1712 // FIXME: Technically specifying a precision or field width here
1713 // makes no sense. Worth issuing a warning at some point.
1717 // Consume the argument.
1718 unsigned argIndex = FS.getArgIndex();
1719 if (argIndex < NumDataArgs) {
1720 // The check to see if the argIndex is valid will come later.
1721 // We set the bit here because we may exit early from this
1722 // function if we encounter some other error.
1723 CoveredArgs.set(argIndex);
1726 // Check the length modifier is valid with the given conversion specifier.
1727 const LengthModifier &LM = FS.getLengthModifier();
1728 if (!FS.hasValidLengthModifier()) {
1729 S.Diag(getLocationOfByte(LM.getStart()),
1730 diag::warn_format_nonsensical_length)
1731 << LM.toString() << CS.toString()
1732 << getSpecifierRange(startSpecifier, specifierLen)
1733 << FixItHint::CreateRemoval(getSpecifierRange(LM.getStart(),
1737 // The remaining checks depend on the data arguments.
1741 if (!CheckNumArgs(FS, CS, startSpecifier, specifierLen, argIndex))
1744 // FIXME: Check that the argument type matches the format specifier.
1749 void Sema::CheckFormatString(const StringLiteral *FExpr,
1750 const Expr *OrigFormatExpr,
1751 const CallExpr *TheCall, bool HasVAListArg,
1752 unsigned format_idx, unsigned firstDataArg,
1755 // CHECK: is the format string a wide literal?
1756 if (FExpr->isWide()) {
1757 Diag(FExpr->getLocStart(),
1758 diag::warn_format_string_is_wide_literal)
1759 << OrigFormatExpr->getSourceRange();
1763 // Str - The format string. NOTE: this is NOT null-terminated!
1764 llvm::StringRef StrRef = FExpr->getString();
1765 const char *Str = StrRef.data();
1766 unsigned StrLen = StrRef.size();
1768 // CHECK: empty format string?
1770 Diag(FExpr->getLocStart(), diag::warn_empty_format_string)
1771 << OrigFormatExpr->getSourceRange();
1776 CheckPrintfHandler H(*this, FExpr, OrigFormatExpr, firstDataArg,
1777 TheCall->getNumArgs() - firstDataArg,
1778 isa<ObjCStringLiteral>(OrigFormatExpr), Str,
1779 HasVAListArg, TheCall, format_idx);
1781 if (!analyze_format_string::ParsePrintfString(H, Str, Str + StrLen))
1785 CheckScanfHandler H(*this, FExpr, OrigFormatExpr, firstDataArg,
1786 TheCall->getNumArgs() - firstDataArg,
1787 isa<ObjCStringLiteral>(OrigFormatExpr), Str,
1788 HasVAListArg, TheCall, format_idx);
1790 if (!analyze_format_string::ParseScanfString(H, Str, Str + StrLen))
1795 //===--- CHECK: Return Address of Stack Variable --------------------------===//
1797 static DeclRefExpr* EvalVal(Expr *E);
1798 static DeclRefExpr* EvalAddr(Expr* E);
1800 /// CheckReturnStackAddr - Check if a return statement returns the address
1801 /// of a stack variable.
1803 Sema::CheckReturnStackAddr(Expr *RetValExp, QualType lhsType,
1804 SourceLocation ReturnLoc) {
1806 // Perform checking for returned stack addresses.
1807 if (lhsType->isPointerType() || lhsType->isBlockPointerType()) {
1808 if (DeclRefExpr *DR = EvalAddr(RetValExp))
1809 Diag(DR->getLocStart(), diag::warn_ret_stack_addr)
1810 << DR->getDecl()->getDeclName() << RetValExp->getSourceRange();
1812 // Skip over implicit cast expressions when checking for block expressions.
1813 RetValExp = RetValExp->IgnoreParenCasts();
1815 if (BlockExpr *C = dyn_cast<BlockExpr>(RetValExp))
1816 if (C->hasBlockDeclRefExprs())
1817 Diag(C->getLocStart(), diag::err_ret_local_block)
1818 << C->getSourceRange();
1820 if (AddrLabelExpr *ALE = dyn_cast<AddrLabelExpr>(RetValExp))
1821 Diag(ALE->getLocStart(), diag::warn_ret_addr_label)
1822 << ALE->getSourceRange();
1824 } else if (lhsType->isReferenceType()) {
1825 // Perform checking for stack values returned by reference.
1826 // Check for a reference to the stack
1827 if (DeclRefExpr *DR = EvalVal(RetValExp))
1828 Diag(DR->getLocStart(), diag::warn_ret_stack_ref)
1829 << DR->getDecl()->getDeclName() << RetValExp->getSourceRange();
1833 /// EvalAddr - EvalAddr and EvalVal are mutually recursive functions that
1834 /// check if the expression in a return statement evaluates to an address
1835 /// to a location on the stack. The recursion is used to traverse the
1836 /// AST of the return expression, with recursion backtracking when we
1837 /// encounter a subexpression that (1) clearly does not lead to the address
1838 /// of a stack variable or (2) is something we cannot determine leads to
1839 /// the address of a stack variable based on such local checking.
1841 /// EvalAddr processes expressions that are pointers that are used as
1842 /// references (and not L-values). EvalVal handles all other values.
1843 /// At the base case of the recursion is a check for a DeclRefExpr* in
1844 /// the refers to a stack variable.
1846 /// This implementation handles:
1848 /// * pointer-to-pointer casts
1849 /// * implicit conversions from array references to pointers
1850 /// * taking the address of fields
1851 /// * arbitrary interplay between "&" and "*" operators
1852 /// * pointer arithmetic from an address of a stack variable
1853 /// * taking the address of an array element where the array is on the stack
1854 static DeclRefExpr* EvalAddr(Expr *E) {
1855 // We should only be called for evaluating pointer expressions.
1856 assert((E->getType()->isAnyPointerType() ||
1857 E->getType()->isBlockPointerType() ||
1858 E->getType()->isObjCQualifiedIdType()) &&
1859 "EvalAddr only works on pointers");
1861 // Our "symbolic interpreter" is just a dispatch off the currently
1862 // viewed AST node. We then recursively traverse the AST by calling
1863 // EvalAddr and EvalVal appropriately.
1864 switch (E->getStmtClass()) {
1865 case Stmt::ParenExprClass:
1866 // Ignore parentheses.
1867 return EvalAddr(cast<ParenExpr>(E)->getSubExpr());
1869 case Stmt::UnaryOperatorClass: {
1870 // The only unary operator that make sense to handle here
1871 // is AddrOf. All others don't make sense as pointers.
1872 UnaryOperator *U = cast<UnaryOperator>(E);
1874 if (U->getOpcode() == UO_AddrOf)
1875 return EvalVal(U->getSubExpr());
1880 case Stmt::BinaryOperatorClass: {
1881 // Handle pointer arithmetic. All other binary operators are not valid
1883 BinaryOperator *B = cast<BinaryOperator>(E);
1884 BinaryOperatorKind op = B->getOpcode();
1886 if (op != BO_Add && op != BO_Sub)
1889 Expr *Base = B->getLHS();
1891 // Determine which argument is the real pointer base. It could be
1892 // the RHS argument instead of the LHS.
1893 if (!Base->getType()->isPointerType()) Base = B->getRHS();
1895 assert (Base->getType()->isPointerType());
1896 return EvalAddr(Base);
1899 // For conditional operators we need to see if either the LHS or RHS are
1900 // valid DeclRefExpr*s. If one of them is valid, we return it.
1901 case Stmt::ConditionalOperatorClass: {
1902 ConditionalOperator *C = cast<ConditionalOperator>(E);
1904 // Handle the GNU extension for missing LHS.
1905 if (Expr *lhsExpr = C->getLHS())
1906 if (DeclRefExpr* LHS = EvalAddr(lhsExpr))
1909 return EvalAddr(C->getRHS());
1912 // For casts, we need to handle conversions from arrays to
1913 // pointer values, and pointer-to-pointer conversions.
1914 case Stmt::ImplicitCastExprClass:
1915 case Stmt::CStyleCastExprClass:
1916 case Stmt::CXXFunctionalCastExprClass: {
1917 Expr* SubExpr = cast<CastExpr>(E)->getSubExpr();
1918 QualType T = SubExpr->getType();
1920 if (SubExpr->getType()->isPointerType() ||
1921 SubExpr->getType()->isBlockPointerType() ||
1922 SubExpr->getType()->isObjCQualifiedIdType())
1923 return EvalAddr(SubExpr);
1924 else if (T->isArrayType())
1925 return EvalVal(SubExpr);
1930 // C++ casts. For dynamic casts, static casts, and const casts, we
1931 // are always converting from a pointer-to-pointer, so we just blow
1932 // through the cast. In the case the dynamic cast doesn't fail (and
1933 // return NULL), we take the conservative route and report cases
1934 // where we return the address of a stack variable. For Reinterpre
1935 // FIXME: The comment about is wrong; we're not always converting
1936 // from pointer to pointer. I'm guessing that this code should also
1937 // handle references to objects.
1938 case Stmt::CXXStaticCastExprClass:
1939 case Stmt::CXXDynamicCastExprClass:
1940 case Stmt::CXXConstCastExprClass:
1941 case Stmt::CXXReinterpretCastExprClass: {
1942 Expr *S = cast<CXXNamedCastExpr>(E)->getSubExpr();
1943 if (S->getType()->isPointerType() || S->getType()->isBlockPointerType())
1949 // Everything else: we simply don't reason about them.
1956 /// EvalVal - This function is complements EvalAddr in the mutual recursion.
1957 /// See the comments for EvalAddr for more details.
1958 static DeclRefExpr* EvalVal(Expr *E) {
1960 // We should only be called for evaluating non-pointer expressions, or
1961 // expressions with a pointer type that are not used as references but instead
1962 // are l-values (e.g., DeclRefExpr with a pointer type).
1964 // Our "symbolic interpreter" is just a dispatch off the currently
1965 // viewed AST node. We then recursively traverse the AST by calling
1966 // EvalAddr and EvalVal appropriately.
1967 switch (E->getStmtClass()) {
1968 case Stmt::ImplicitCastExprClass: {
1969 ImplicitCastExpr *IE = cast<ImplicitCastExpr>(E);
1970 if (IE->getValueKind() == VK_LValue) {
1971 E = IE->getSubExpr();
1977 case Stmt::DeclRefExprClass: {
1978 // DeclRefExpr: the base case. When we hit a DeclRefExpr we are looking
1979 // at code that refers to a variable's name. We check if it has local
1980 // storage within the function, and if so, return the expression.
1981 DeclRefExpr *DR = cast<DeclRefExpr>(E);
1983 if (VarDecl *V = dyn_cast<VarDecl>(DR->getDecl()))
1984 if (V->hasLocalStorage() && !V->getType()->isReferenceType()) return DR;
1989 case Stmt::ParenExprClass: {
1990 // Ignore parentheses.
1991 E = cast<ParenExpr>(E)->getSubExpr();
1995 case Stmt::UnaryOperatorClass: {
1996 // The only unary operator that make sense to handle here
1997 // is Deref. All others don't resolve to a "name." This includes
1998 // handling all sorts of rvalues passed to a unary operator.
1999 UnaryOperator *U = cast<UnaryOperator>(E);
2001 if (U->getOpcode() == UO_Deref)
2002 return EvalAddr(U->getSubExpr());
2007 case Stmt::ArraySubscriptExprClass: {
2008 // Array subscripts are potential references to data on the stack. We
2009 // retrieve the DeclRefExpr* for the array variable if it indeed
2010 // has local storage.
2011 return EvalAddr(cast<ArraySubscriptExpr>(E)->getBase());
2014 case Stmt::ConditionalOperatorClass: {
2015 // For conditional operators we need to see if either the LHS or RHS are
2016 // non-NULL DeclRefExpr's. If one is non-NULL, we return it.
2017 ConditionalOperator *C = cast<ConditionalOperator>(E);
2019 // Handle the GNU extension for missing LHS.
2020 if (Expr *lhsExpr = C->getLHS())
2021 if (DeclRefExpr *LHS = EvalVal(lhsExpr))
2024 return EvalVal(C->getRHS());
2027 // Accesses to members are potential references to data on the stack.
2028 case Stmt::MemberExprClass: {
2029 MemberExpr *M = cast<MemberExpr>(E);
2031 // Check for indirect access. We only want direct field accesses.
2035 // Check whether the member type is itself a reference, in which case
2036 // we're not going to refer to the member, but to what the member refers to.
2037 if (M->getMemberDecl()->getType()->isReferenceType())
2040 return EvalVal(M->getBase());
2043 // Everything else: we simply don't reason about them.
2050 //===--- CHECK: Floating-Point comparisons (-Wfloat-equal) ---------------===//
2052 /// Check for comparisons of floating point operands using != and ==.
2053 /// Issue a warning if these are no self-comparisons, as they are not likely
2054 /// to do what the programmer intended.
2055 void Sema::CheckFloatComparison(SourceLocation loc, Expr* lex, Expr *rex) {
2056 bool EmitWarning = true;
2058 Expr* LeftExprSansParen = lex->IgnoreParens();
2059 Expr* RightExprSansParen = rex->IgnoreParens();
2061 // Special case: check for x == x (which is OK).
2062 // Do not emit warnings for such cases.
2063 if (DeclRefExpr* DRL = dyn_cast<DeclRefExpr>(LeftExprSansParen))
2064 if (DeclRefExpr* DRR = dyn_cast<DeclRefExpr>(RightExprSansParen))
2065 if (DRL->getDecl() == DRR->getDecl())
2066 EmitWarning = false;
2069 // Special case: check for comparisons against literals that can be exactly
2070 // represented by APFloat. In such cases, do not emit a warning. This
2071 // is a heuristic: often comparison against such literals are used to
2072 // detect if a value in a variable has not changed. This clearly can
2073 // lead to false negatives.
2075 if (FloatingLiteral* FLL = dyn_cast<FloatingLiteral>(LeftExprSansParen)) {
2077 EmitWarning = false;
2079 if (FloatingLiteral* FLR = dyn_cast<FloatingLiteral>(RightExprSansParen)){
2081 EmitWarning = false;
2085 // Check for comparisons with builtin types.
2087 if (CallExpr* CL = dyn_cast<CallExpr>(LeftExprSansParen))
2088 if (CL->isBuiltinCall(Context))
2089 EmitWarning = false;
2092 if (CallExpr* CR = dyn_cast<CallExpr>(RightExprSansParen))
2093 if (CR->isBuiltinCall(Context))
2094 EmitWarning = false;
2096 // Emit the diagnostic.
2098 Diag(loc, diag::warn_floatingpoint_eq)
2099 << lex->getSourceRange() << rex->getSourceRange();
2102 //===--- CHECK: Integer mixed-sign comparisons (-Wsign-compare) --------===//
2103 //===--- CHECK: Lossy implicit conversions (-Wconversion) --------------===//
2107 /// Structure recording the 'active' range of an integer-valued
2110 /// The number of bits active in the int.
2113 /// True if the int is known not to have negative values.
2116 IntRange(unsigned Width, bool NonNegative)
2117 : Width(Width), NonNegative(NonNegative)
2120 // Returns the range of the bool type.
2121 static IntRange forBoolType() {
2122 return IntRange(1, true);
2125 // Returns the range of an integral type.
2126 static IntRange forType(ASTContext &C, QualType T) {
2127 return forCanonicalType(C, T->getCanonicalTypeInternal().getTypePtr());
2130 // Returns the range of an integeral type based on its canonical
2132 static IntRange forCanonicalType(ASTContext &C, const Type *T) {
2133 assert(T->isCanonicalUnqualified());
2135 if (const VectorType *VT = dyn_cast<VectorType>(T))
2136 T = VT->getElementType().getTypePtr();
2137 if (const ComplexType *CT = dyn_cast<ComplexType>(T))
2138 T = CT->getElementType().getTypePtr();
2140 if (const EnumType *ET = dyn_cast<EnumType>(T)) {
2141 EnumDecl *Enum = ET->getDecl();
2142 unsigned NumPositive = Enum->getNumPositiveBits();
2143 unsigned NumNegative = Enum->getNumNegativeBits();
2145 return IntRange(std::max(NumPositive, NumNegative), NumNegative == 0);
2148 const BuiltinType *BT = cast<BuiltinType>(T);
2149 assert(BT->isInteger());
2151 return IntRange(C.getIntWidth(QualType(T, 0)), BT->isUnsignedInteger());
2154 // Returns the supremum of two ranges: i.e. their conservative merge.
2155 static IntRange join(IntRange L, IntRange R) {
2156 return IntRange(std::max(L.Width, R.Width),
2157 L.NonNegative && R.NonNegative);
2160 // Returns the infinum of two ranges: i.e. their aggressive merge.
2161 static IntRange meet(IntRange L, IntRange R) {
2162 return IntRange(std::min(L.Width, R.Width),
2163 L.NonNegative || R.NonNegative);
2167 IntRange GetValueRange(ASTContext &C, llvm::APSInt &value, unsigned MaxWidth) {
2168 if (value.isSigned() && value.isNegative())
2169 return IntRange(value.getMinSignedBits(), false);
2171 if (value.getBitWidth() > MaxWidth)
2172 value.trunc(MaxWidth);
2174 // isNonNegative() just checks the sign bit without considering
2176 return IntRange(value.getActiveBits(), true);
2179 IntRange GetValueRange(ASTContext &C, APValue &result, QualType Ty,
2180 unsigned MaxWidth) {
2182 return GetValueRange(C, result.getInt(), MaxWidth);
2184 if (result.isVector()) {
2185 IntRange R = GetValueRange(C, result.getVectorElt(0), Ty, MaxWidth);
2186 for (unsigned i = 1, e = result.getVectorLength(); i != e; ++i) {
2187 IntRange El = GetValueRange(C, result.getVectorElt(i), Ty, MaxWidth);
2188 R = IntRange::join(R, El);
2193 if (result.isComplexInt()) {
2194 IntRange R = GetValueRange(C, result.getComplexIntReal(), MaxWidth);
2195 IntRange I = GetValueRange(C, result.getComplexIntImag(), MaxWidth);
2196 return IntRange::join(R, I);
2199 // This can happen with lossless casts to intptr_t of "based" lvalues.
2200 // Assume it might use arbitrary bits.
2201 // FIXME: The only reason we need to pass the type in here is to get
2202 // the sign right on this one case. It would be nice if APValue
2204 assert(result.isLValue());
2205 return IntRange(MaxWidth, Ty->isUnsignedIntegerType());
2208 /// Pseudo-evaluate the given integer expression, estimating the
2209 /// range of values it might take.
2211 /// \param MaxWidth - the width to which the value will be truncated
2212 IntRange GetExprRange(ASTContext &C, Expr *E, unsigned MaxWidth) {
2213 E = E->IgnoreParens();
2215 // Try a full evaluation first.
2216 Expr::EvalResult result;
2217 if (E->Evaluate(result, C))
2218 return GetValueRange(C, result.Val, E->getType(), MaxWidth);
2220 // I think we only want to look through implicit casts here; if the
2221 // user has an explicit widening cast, we should treat the value as
2222 // being of the new, wider type.
2223 if (ImplicitCastExpr *CE = dyn_cast<ImplicitCastExpr>(E)) {
2224 if (CE->getCastKind() == CK_NoOp)
2225 return GetExprRange(C, CE->getSubExpr(), MaxWidth);
2227 IntRange OutputTypeRange = IntRange::forType(C, CE->getType());
2229 bool isIntegerCast = (CE->getCastKind() == CK_IntegralCast);
2230 if (!isIntegerCast && CE->getCastKind() == CK_Unknown)
2231 isIntegerCast = CE->getSubExpr()->getType()->isIntegerType();
2233 // Assume that non-integer casts can span the full range of the type.
2235 return OutputTypeRange;
2238 = GetExprRange(C, CE->getSubExpr(),
2239 std::min(MaxWidth, OutputTypeRange.Width));
2241 // Bail out if the subexpr's range is as wide as the cast type.
2242 if (SubRange.Width >= OutputTypeRange.Width)
2243 return OutputTypeRange;
2245 // Otherwise, we take the smaller width, and we're non-negative if
2246 // either the output type or the subexpr is.
2247 return IntRange(SubRange.Width,
2248 SubRange.NonNegative || OutputTypeRange.NonNegative);
2251 if (ConditionalOperator *CO = dyn_cast<ConditionalOperator>(E)) {
2252 // If we can fold the condition, just take that operand.
2254 if (CO->getCond()->EvaluateAsBooleanCondition(CondResult, C))
2255 return GetExprRange(C, CondResult ? CO->getTrueExpr()
2256 : CO->getFalseExpr(),
2259 // Otherwise, conservatively merge.
2260 IntRange L = GetExprRange(C, CO->getTrueExpr(), MaxWidth);
2261 IntRange R = GetExprRange(C, CO->getFalseExpr(), MaxWidth);
2262 return IntRange::join(L, R);
2265 if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) {
2266 switch (BO->getOpcode()) {
2268 // Boolean-valued operations are single-bit and positive.
2277 return IntRange::forBoolType();
2279 // The type of these compound assignments is the type of the LHS,
2280 // so the RHS is not necessarily an integer.
2286 return IntRange::forType(C, E->getType());
2288 // Operations with opaque sources are black-listed.
2291 return IntRange::forType(C, E->getType());
2293 // Bitwise-and uses the *infinum* of the two source ranges.
2296 return IntRange::meet(GetExprRange(C, BO->getLHS(), MaxWidth),
2297 GetExprRange(C, BO->getRHS(), MaxWidth));
2299 // Left shift gets black-listed based on a judgement call.
2301 // ...except that we want to treat '1 << (blah)' as logically
2302 // positive. It's an important idiom.
2303 if (IntegerLiteral *I
2304 = dyn_cast<IntegerLiteral>(BO->getLHS()->IgnoreParenCasts())) {
2305 if (I->getValue() == 1) {
2306 IntRange R = IntRange::forType(C, E->getType());
2307 return IntRange(R.Width, /*NonNegative*/ true);
2313 return IntRange::forType(C, E->getType());
2315 // Right shift by a constant can narrow its left argument.
2317 case BO_ShrAssign: {
2318 IntRange L = GetExprRange(C, BO->getLHS(), MaxWidth);
2320 // If the shift amount is a positive constant, drop the width by
2323 if (BO->getRHS()->isIntegerConstantExpr(shift, C) &&
2324 shift.isNonNegative()) {
2325 unsigned zext = shift.getZExtValue();
2326 if (zext >= L.Width)
2327 L.Width = (L.NonNegative ? 0 : 1);
2335 // Comma acts as its right operand.
2337 return GetExprRange(C, BO->getRHS(), MaxWidth);
2339 // Black-list pointer subtractions.
2341 if (BO->getLHS()->getType()->isPointerType())
2342 return IntRange::forType(C, E->getType());
2349 // Treat every other operator as if it were closed on the
2350 // narrowest type that encompasses both operands.
2351 IntRange L = GetExprRange(C, BO->getLHS(), MaxWidth);
2352 IntRange R = GetExprRange(C, BO->getRHS(), MaxWidth);
2353 return IntRange::join(L, R);
2356 if (UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) {
2357 switch (UO->getOpcode()) {
2358 // Boolean-valued operations are white-listed.
2360 return IntRange::forBoolType();
2362 // Operations with opaque sources are black-listed.
2364 case UO_AddrOf: // should be impossible
2365 return IntRange::forType(C, E->getType());
2368 return GetExprRange(C, UO->getSubExpr(), MaxWidth);
2372 if (dyn_cast<OffsetOfExpr>(E)) {
2373 IntRange::forType(C, E->getType());
2376 FieldDecl *BitField = E->getBitField();
2378 llvm::APSInt BitWidthAP = BitField->getBitWidth()->EvaluateAsInt(C);
2379 unsigned BitWidth = BitWidthAP.getZExtValue();
2381 return IntRange(BitWidth, BitField->getType()->isUnsignedIntegerType());
2384 return IntRange::forType(C, E->getType());
2387 IntRange GetExprRange(ASTContext &C, Expr *E) {
2388 return GetExprRange(C, E, C.getIntWidth(E->getType()));
2391 /// Checks whether the given value, which currently has the given
2392 /// source semantics, has the same value when coerced through the
2393 /// target semantics.
2394 bool IsSameFloatAfterCast(const llvm::APFloat &value,
2395 const llvm::fltSemantics &Src,
2396 const llvm::fltSemantics &Tgt) {
2397 llvm::APFloat truncated = value;
2400 truncated.convert(Src, llvm::APFloat::rmNearestTiesToEven, &ignored);
2401 truncated.convert(Tgt, llvm::APFloat::rmNearestTiesToEven, &ignored);
2403 return truncated.bitwiseIsEqual(value);
2406 /// Checks whether the given value, which currently has the given
2407 /// source semantics, has the same value when coerced through the
2408 /// target semantics.
2410 /// The value might be a vector of floats (or a complex number).
2411 bool IsSameFloatAfterCast(const APValue &value,
2412 const llvm::fltSemantics &Src,
2413 const llvm::fltSemantics &Tgt) {
2414 if (value.isFloat())
2415 return IsSameFloatAfterCast(value.getFloat(), Src, Tgt);
2417 if (value.isVector()) {
2418 for (unsigned i = 0, e = value.getVectorLength(); i != e; ++i)
2419 if (!IsSameFloatAfterCast(value.getVectorElt(i), Src, Tgt))
2424 assert(value.isComplexFloat());
2425 return (IsSameFloatAfterCast(value.getComplexFloatReal(), Src, Tgt) &&
2426 IsSameFloatAfterCast(value.getComplexFloatImag(), Src, Tgt));
2429 void AnalyzeImplicitConversions(Sema &S, Expr *E);
2431 bool IsZero(Sema &S, Expr *E) {
2433 return E->isIntegerConstantExpr(Value, S.Context) && Value == 0;
2436 void CheckTrivialUnsignedComparison(Sema &S, BinaryOperator *E) {
2437 BinaryOperatorKind op = E->getOpcode();
2438 if (op == BO_LT && IsZero(S, E->getRHS())) {
2439 S.Diag(E->getOperatorLoc(), diag::warn_lunsigned_always_true_comparison)
2441 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange();
2442 } else if (op == BO_GE && IsZero(S, E->getRHS())) {
2443 S.Diag(E->getOperatorLoc(), diag::warn_lunsigned_always_true_comparison)
2445 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange();
2446 } else if (op == BO_GT && IsZero(S, E->getLHS())) {
2447 S.Diag(E->getOperatorLoc(), diag::warn_runsigned_always_true_comparison)
2449 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange();
2450 } else if (op == BO_LE && IsZero(S, E->getLHS())) {
2451 S.Diag(E->getOperatorLoc(), diag::warn_runsigned_always_true_comparison)
2453 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange();
2457 /// Analyze the operands of the given comparison. Implements the
2458 /// fallback case from AnalyzeComparison.
2459 void AnalyzeImpConvsInComparison(Sema &S, BinaryOperator *E) {
2460 AnalyzeImplicitConversions(S, E->getLHS());
2461 AnalyzeImplicitConversions(S, E->getRHS());
2464 /// \brief Implements -Wsign-compare.
2466 /// \param lex the left-hand expression
2467 /// \param rex the right-hand expression
2468 /// \param OpLoc the location of the joining operator
2469 /// \param BinOpc binary opcode or 0
2470 void AnalyzeComparison(Sema &S, BinaryOperator *E) {
2471 // The type the comparison is being performed in.
2472 QualType T = E->getLHS()->getType();
2473 assert(S.Context.hasSameUnqualifiedType(T, E->getRHS()->getType())
2474 && "comparison with mismatched types");
2476 // We don't do anything special if this isn't an unsigned integral
2477 // comparison: we're only interested in integral comparisons, and
2478 // signed comparisons only happen in cases we don't care to warn about.
2479 if (!T->hasUnsignedIntegerRepresentation())
2480 return AnalyzeImpConvsInComparison(S, E);
2482 Expr *lex = E->getLHS()->IgnoreParenImpCasts();
2483 Expr *rex = E->getRHS()->IgnoreParenImpCasts();
2485 // Check to see if one of the (unmodified) operands is of different
2487 Expr *signedOperand, *unsignedOperand;
2488 if (lex->getType()->hasSignedIntegerRepresentation()) {
2489 assert(!rex->getType()->hasSignedIntegerRepresentation() &&
2490 "unsigned comparison between two signed integer expressions?");
2491 signedOperand = lex;
2492 unsignedOperand = rex;
2493 } else if (rex->getType()->hasSignedIntegerRepresentation()) {
2494 signedOperand = rex;
2495 unsignedOperand = lex;
2497 CheckTrivialUnsignedComparison(S, E);
2498 return AnalyzeImpConvsInComparison(S, E);
2501 // Otherwise, calculate the effective range of the signed operand.
2502 IntRange signedRange = GetExprRange(S.Context, signedOperand);
2504 // Go ahead and analyze implicit conversions in the operands. Note
2505 // that we skip the implicit conversions on both sides.
2506 AnalyzeImplicitConversions(S, lex);
2507 AnalyzeImplicitConversions(S, rex);
2509 // If the signed range is non-negative, -Wsign-compare won't fire,
2510 // but we should still check for comparisons which are always true
2512 if (signedRange.NonNegative)
2513 return CheckTrivialUnsignedComparison(S, E);
2515 // For (in)equality comparisons, if the unsigned operand is a
2516 // constant which cannot collide with a overflowed signed operand,
2517 // then reinterpreting the signed operand as unsigned will not
2518 // change the result of the comparison.
2519 if (E->isEqualityOp()) {
2520 unsigned comparisonWidth = S.Context.getIntWidth(T);
2521 IntRange unsignedRange = GetExprRange(S.Context, unsignedOperand);
2523 // We should never be unable to prove that the unsigned operand is
2525 assert(unsignedRange.NonNegative && "unsigned range includes negative?");
2527 if (unsignedRange.Width < comparisonWidth)
2531 S.Diag(E->getOperatorLoc(), diag::warn_mixed_sign_comparison)
2532 << lex->getType() << rex->getType()
2533 << lex->getSourceRange() << rex->getSourceRange();
2536 /// Diagnose an implicit cast; purely a helper for CheckImplicitConversion.
2537 void DiagnoseImpCast(Sema &S, Expr *E, QualType T, unsigned diag) {
2538 S.Diag(E->getExprLoc(), diag) << E->getType() << T << E->getSourceRange();
2541 void CheckImplicitConversion(Sema &S, Expr *E, QualType T,
2542 bool *ICContext = 0) {
2543 if (E->isTypeDependent() || E->isValueDependent()) return;
2545 const Type *Source = S.Context.getCanonicalType(E->getType()).getTypePtr();
2546 const Type *Target = S.Context.getCanonicalType(T).getTypePtr();
2547 if (Source == Target) return;
2548 if (Target->isDependentType()) return;
2550 // Never diagnose implicit casts to bool.
2551 if (Target->isSpecificBuiltinType(BuiltinType::Bool))
2554 // Strip vector types.
2555 if (isa<VectorType>(Source)) {
2556 if (!isa<VectorType>(Target))
2557 return DiagnoseImpCast(S, E, T, diag::warn_impcast_vector_scalar);
2559 Source = cast<VectorType>(Source)->getElementType().getTypePtr();
2560 Target = cast<VectorType>(Target)->getElementType().getTypePtr();
2563 // Strip complex types.
2564 if (isa<ComplexType>(Source)) {
2565 if (!isa<ComplexType>(Target))
2566 return DiagnoseImpCast(S, E, T, diag::warn_impcast_complex_scalar);
2568 Source = cast<ComplexType>(Source)->getElementType().getTypePtr();
2569 Target = cast<ComplexType>(Target)->getElementType().getTypePtr();
2572 const BuiltinType *SourceBT = dyn_cast<BuiltinType>(Source);
2573 const BuiltinType *TargetBT = dyn_cast<BuiltinType>(Target);
2575 // If the source is floating point...
2576 if (SourceBT && SourceBT->isFloatingPoint()) {
2577 // ...and the target is floating point...
2578 if (TargetBT && TargetBT->isFloatingPoint()) {
2579 // ...then warn if we're dropping FP rank.
2581 // Builtin FP kinds are ordered by increasing FP rank.
2582 if (SourceBT->getKind() > TargetBT->getKind()) {
2583 // Don't warn about float constants that are precisely
2584 // representable in the target type.
2585 Expr::EvalResult result;
2586 if (E->Evaluate(result, S.Context)) {
2587 // Value might be a float, a float vector, or a float complex.
2588 if (IsSameFloatAfterCast(result.Val,
2589 S.Context.getFloatTypeSemantics(QualType(TargetBT, 0)),
2590 S.Context.getFloatTypeSemantics(QualType(SourceBT, 0))))
2594 DiagnoseImpCast(S, E, T, diag::warn_impcast_float_precision);
2599 // If the target is integral, always warn.
2600 if ((TargetBT && TargetBT->isInteger()))
2601 // TODO: don't warn for integer values?
2602 DiagnoseImpCast(S, E, T, diag::warn_impcast_float_integer);
2607 if (!Source->isIntegerType() || !Target->isIntegerType())
2610 IntRange SourceRange = GetExprRange(S.Context, E);
2611 IntRange TargetRange = IntRange::forCanonicalType(S.Context, Target);
2613 if (SourceRange.Width > TargetRange.Width) {
2614 // People want to build with -Wshorten-64-to-32 and not -Wconversion
2615 // and by god we'll let them.
2616 if (SourceRange.Width == 64 && TargetRange.Width == 32)
2617 return DiagnoseImpCast(S, E, T, diag::warn_impcast_integer_64_32);
2618 return DiagnoseImpCast(S, E, T, diag::warn_impcast_integer_precision);
2621 if ((TargetRange.NonNegative && !SourceRange.NonNegative) ||
2622 (!TargetRange.NonNegative && SourceRange.NonNegative &&
2623 SourceRange.Width == TargetRange.Width)) {
2624 unsigned DiagID = diag::warn_impcast_integer_sign;
2626 // Traditionally, gcc has warned about this under -Wsign-compare.
2627 // We also want to warn about it in -Wconversion.
2628 // So if -Wconversion is off, use a completely identical diagnostic
2629 // in the sign-compare group.
2630 // The conditional-checking code will
2632 DiagID = diag::warn_impcast_integer_sign_conditional;
2636 return DiagnoseImpCast(S, E, T, DiagID);
2642 void CheckConditionalOperator(Sema &S, ConditionalOperator *E, QualType T);
2644 void CheckConditionalOperand(Sema &S, Expr *E, QualType T,
2646 E = E->IgnoreParenImpCasts();
2648 if (isa<ConditionalOperator>(E))
2649 return CheckConditionalOperator(S, cast<ConditionalOperator>(E), T);
2651 AnalyzeImplicitConversions(S, E);
2652 if (E->getType() != T)
2653 return CheckImplicitConversion(S, E, T, &ICContext);
2657 void CheckConditionalOperator(Sema &S, ConditionalOperator *E, QualType T) {
2658 AnalyzeImplicitConversions(S, E->getCond());
2660 bool Suspicious = false;
2661 CheckConditionalOperand(S, E->getTrueExpr(), T, Suspicious);
2662 CheckConditionalOperand(S, E->getFalseExpr(), T, Suspicious);
2664 // If -Wconversion would have warned about either of the candidates
2665 // for a signedness conversion to the context type...
2666 if (!Suspicious) return;
2668 // ...but it's currently ignored...
2669 if (S.Diags.getDiagnosticLevel(diag::warn_impcast_integer_sign_conditional))
2672 // ...and -Wsign-compare isn't...
2673 if (!S.Diags.getDiagnosticLevel(diag::warn_mixed_sign_conditional))
2676 // ...then check whether it would have warned about either of the
2677 // candidates for a signedness conversion to the condition type.
2678 if (E->getType() != T) {
2680 CheckImplicitConversion(S, E->getTrueExpr()->IgnoreParenImpCasts(),
2681 E->getType(), &Suspicious);
2683 CheckImplicitConversion(S, E->getFalseExpr()->IgnoreParenImpCasts(),
2684 E->getType(), &Suspicious);
2689 // If so, emit a diagnostic under -Wsign-compare.
2690 Expr *lex = E->getTrueExpr()->IgnoreParenImpCasts();
2691 Expr *rex = E->getFalseExpr()->IgnoreParenImpCasts();
2692 S.Diag(E->getQuestionLoc(), diag::warn_mixed_sign_conditional)
2693 << lex->getType() << rex->getType()
2694 << lex->getSourceRange() << rex->getSourceRange();
2697 /// AnalyzeImplicitConversions - Find and report any interesting
2698 /// implicit conversions in the given expression. There are a couple
2699 /// of competing diagnostics here, -Wconversion and -Wsign-compare.
2700 void AnalyzeImplicitConversions(Sema &S, Expr *OrigE) {
2701 QualType T = OrigE->getType();
2702 Expr *E = OrigE->IgnoreParenImpCasts();
2704 // For conditional operators, we analyze the arguments as if they
2705 // were being fed directly into the output.
2706 if (isa<ConditionalOperator>(E)) {
2707 ConditionalOperator *CO = cast<ConditionalOperator>(E);
2708 CheckConditionalOperator(S, CO, T);
2712 // Go ahead and check any implicit conversions we might have skipped.
2713 // The non-canonical typecheck is just an optimization;
2714 // CheckImplicitConversion will filter out dead implicit conversions.
2715 if (E->getType() != T)
2716 CheckImplicitConversion(S, E, T);
2718 // Now continue drilling into this expression.
2720 // Skip past explicit casts.
2721 if (isa<ExplicitCastExpr>(E)) {
2722 E = cast<ExplicitCastExpr>(E)->getSubExpr()->IgnoreParenImpCasts();
2723 return AnalyzeImplicitConversions(S, E);
2726 // Do a somewhat different check with comparison operators.
2727 if (isa<BinaryOperator>(E) && cast<BinaryOperator>(E)->isComparisonOp())
2728 return AnalyzeComparison(S, cast<BinaryOperator>(E));
2730 // These break the otherwise-useful invariant below. Fortunately,
2731 // we don't really need to recurse into them, because any internal
2732 // expressions should have been analyzed already when they were
2733 // built into statements.
2734 if (isa<StmtExpr>(E)) return;
2736 // Don't descend into unevaluated contexts.
2737 if (isa<SizeOfAlignOfExpr>(E)) return;
2739 // Now just recurse over the expression's children.
2740 for (Stmt::child_iterator I = E->child_begin(), IE = E->child_end();
2742 AnalyzeImplicitConversions(S, cast<Expr>(*I));
2745 } // end anonymous namespace
2747 /// Diagnoses "dangerous" implicit conversions within the given
2748 /// expression (which is a full expression). Implements -Wconversion
2749 /// and -Wsign-compare.
2750 void Sema::CheckImplicitConversions(Expr *E) {
2751 // Don't diagnose in unevaluated contexts.
2752 if (ExprEvalContexts.back().Context == Sema::Unevaluated)
2755 // Don't diagnose for value- or type-dependent expressions.
2756 if (E->isTypeDependent() || E->isValueDependent())
2759 AnalyzeImplicitConversions(*this, E);
2762 /// CheckParmsForFunctionDef - Check that the parameters of the given
2763 /// function are appropriate for the definition of a function. This
2764 /// takes care of any checks that cannot be performed on the
2765 /// declaration itself, e.g., that the types of each of the function
2766 /// parameters are complete.
2767 bool Sema::CheckParmsForFunctionDef(FunctionDecl *FD) {
2768 bool HasInvalidParm = false;
2769 for (unsigned p = 0, NumParams = FD->getNumParams(); p < NumParams; ++p) {
2770 ParmVarDecl *Param = FD->getParamDecl(p);
2772 // C99 6.7.5.3p4: the parameters in a parameter type list in a
2773 // function declarator that is part of a function definition of
2774 // that function shall not have incomplete type.
2776 // This is also C++ [dcl.fct]p6.
2777 if (!Param->isInvalidDecl() &&
2778 RequireCompleteType(Param->getLocation(), Param->getType(),
2779 diag::err_typecheck_decl_incomplete_type)) {
2780 Param->setInvalidDecl();
2781 HasInvalidParm = true;
2784 // C99 6.9.1p5: If the declarator includes a parameter type list, the
2785 // declaration of each parameter shall include an identifier.
2786 if (Param->getIdentifier() == 0 &&
2787 !Param->isImplicit() &&
2788 !getLangOptions().CPlusPlus)
2789 Diag(Param->getLocation(), diag::err_parameter_name_omitted);
2792 // If the function declarator is not part of a definition of that
2793 // function, parameters may have incomplete type and may use the [*]
2794 // notation in their sequences of declarator specifiers to specify
2795 // variable length array types.
2796 QualType PType = Param->getOriginalType();
2797 if (const ArrayType *AT = Context.getAsArrayType(PType)) {
2798 if (AT->getSizeModifier() == ArrayType::Star) {
2799 // FIXME: This diagnosic should point the the '[*]' if source-location
2800 // information is added for it.
2801 Diag(Param->getLocation(), diag::err_array_star_in_function_definition);
2806 return HasInvalidParm;
2809 /// CheckCastAlign - Implements -Wcast-align, which warns when a
2810 /// pointer cast increases the alignment requirements.
2811 void Sema::CheckCastAlign(Expr *Op, QualType T, SourceRange TRange) {
2812 // This is actually a lot of work to potentially be doing on every
2813 // cast; don't do it if we're ignoring -Wcast_align (as is the default).
2814 if (getDiagnostics().getDiagnosticLevel(diag::warn_cast_align)
2815 == Diagnostic::Ignored)
2818 // Ignore dependent types.
2819 if (T->isDependentType() || Op->getType()->isDependentType())
2822 // Require that the destination be a pointer type.
2823 const PointerType *DestPtr = T->getAs<PointerType>();
2824 if (!DestPtr) return;
2826 // If the destination has alignment 1, we're done.
2827 QualType DestPointee = DestPtr->getPointeeType();
2828 if (DestPointee->isIncompleteType()) return;
2829 CharUnits DestAlign = Context.getTypeAlignInChars(DestPointee);
2830 if (DestAlign.isOne()) return;
2832 // Require that the source be a pointer type.
2833 const PointerType *SrcPtr = Op->getType()->getAs<PointerType>();
2834 if (!SrcPtr) return;
2835 QualType SrcPointee = SrcPtr->getPointeeType();
2837 // Whitelist casts from cv void*. We already implicitly
2838 // whitelisted casts to cv void*, since they have alignment 1.
2839 // Also whitelist casts involving incomplete types, which implicitly
2841 if (SrcPointee->isIncompleteType()) return;
2843 CharUnits SrcAlign = Context.getTypeAlignInChars(SrcPointee);
2844 if (SrcAlign >= DestAlign) return;
2846 Diag(TRange.getBegin(), diag::warn_cast_align)
2847 << Op->getType() << T
2848 << static_cast<unsigned>(SrcAlign.getQuantity())
2849 << static_cast<unsigned>(DestAlign.getQuantity())
2850 << TRange << Op->getSourceRange();