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 //===----------------------------------------------------------------------===//
16 #include "clang/Analysis/CFG.h"
17 #include "clang/Analysis/PathSensitive/AnalysisContext.h"
18 #include "clang/AST/ASTContext.h"
19 #include "clang/AST/CharUnits.h"
20 #include "clang/AST/DeclObjC.h"
21 #include "clang/AST/ExprCXX.h"
22 #include "clang/AST/ExprObjC.h"
23 #include "clang/AST/DeclObjC.h"
24 #include "clang/AST/StmtCXX.h"
25 #include "clang/AST/StmtObjC.h"
26 #include "clang/Lex/LiteralSupport.h"
27 #include "clang/Lex/Preprocessor.h"
28 #include "llvm/ADT/BitVector.h"
29 #include "llvm/ADT/STLExtras.h"
32 using namespace clang;
34 /// getLocationOfStringLiteralByte - Return a source location that points to the
35 /// specified byte of the specified string literal.
37 /// Strings are amazingly complex. They can be formed from multiple tokens and
38 /// can have escape sequences in them in addition to the usual trigraph and
39 /// escaped newline business. This routine handles this complexity.
41 SourceLocation Sema::getLocationOfStringLiteralByte(const StringLiteral *SL,
42 unsigned ByteNo) const {
43 assert(!SL->isWide() && "This doesn't work for wide strings yet");
45 // Loop over all of the tokens in this string until we find the one that
46 // contains the byte we're looking for.
49 assert(TokNo < SL->getNumConcatenated() && "Invalid byte number!");
50 SourceLocation StrTokLoc = SL->getStrTokenLoc(TokNo);
52 // Get the spelling of the string so that we can get the data that makes up
53 // the string literal, not the identifier for the macro it is potentially
55 SourceLocation StrTokSpellingLoc = SourceMgr.getSpellingLoc(StrTokLoc);
57 // Re-lex the token to get its length and original spelling.
58 std::pair<FileID, unsigned> LocInfo =
59 SourceMgr.getDecomposedLoc(StrTokSpellingLoc);
60 std::pair<const char *,const char *> Buffer =
61 SourceMgr.getBufferData(LocInfo.first);
62 const char *StrData = Buffer.first+LocInfo.second;
64 // Create a langops struct and enable trigraphs. This is sufficient for
67 LangOpts.Trigraphs = true;
69 // Create a lexer starting at the beginning of this token.
70 Lexer TheLexer(StrTokSpellingLoc, LangOpts, Buffer.first, StrData,
73 TheLexer.LexFromRawLexer(TheTok);
75 // Use the StringLiteralParser to compute the length of the string in bytes.
76 StringLiteralParser SLP(&TheTok, 1, PP);
77 unsigned TokNumBytes = SLP.GetStringLength();
79 // If the byte is in this token, return the location of the byte.
80 if (ByteNo < TokNumBytes ||
81 (ByteNo == TokNumBytes && TokNo == SL->getNumConcatenated())) {
83 StringLiteralParser::getOffsetOfStringByte(TheTok, ByteNo, PP);
85 // Now that we know the offset of the token in the spelling, use the
86 // preprocessor to get the offset in the original source.
87 return PP.AdvanceToTokenCharacter(StrTokLoc, Offset);
90 // Move to the next string token.
92 ByteNo -= TokNumBytes;
96 /// CheckablePrintfAttr - does a function call have a "printf" attribute
97 /// and arguments that merit checking?
98 bool Sema::CheckablePrintfAttr(const FormatAttr *Format, CallExpr *TheCall) {
99 if (Format->getType() == "printf") return true;
100 if (Format->getType() == "printf0") {
101 // printf0 allows null "format" string; if so don't check format/args
102 unsigned format_idx = Format->getFormatIdx() - 1;
103 // Does the index refer to the implicit object argument?
104 if (isa<CXXMemberCallExpr>(TheCall)) {
109 if (format_idx < TheCall->getNumArgs()) {
110 Expr *Format = TheCall->getArg(format_idx)->IgnoreParenCasts();
111 if (!Format->isNullPointerConstant(Context, Expr::NPC_ValueDependentIsNull))
118 Action::OwningExprResult
119 Sema::CheckBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) {
120 OwningExprResult TheCallResult(Owned(TheCall));
123 case Builtin::BI__builtin___CFStringMakeConstantString:
124 assert(TheCall->getNumArgs() == 1 &&
125 "Wrong # arguments to builtin CFStringMakeConstantString");
126 if (CheckObjCString(TheCall->getArg(0)))
129 case Builtin::BI__builtin_stdarg_start:
130 case Builtin::BI__builtin_va_start:
131 if (SemaBuiltinVAStart(TheCall))
134 case Builtin::BI__builtin_isgreater:
135 case Builtin::BI__builtin_isgreaterequal:
136 case Builtin::BI__builtin_isless:
137 case Builtin::BI__builtin_islessequal:
138 case Builtin::BI__builtin_islessgreater:
139 case Builtin::BI__builtin_isunordered:
140 if (SemaBuiltinUnorderedCompare(TheCall))
143 case Builtin::BI__builtin_isfinite:
144 case Builtin::BI__builtin_isinf:
145 case Builtin::BI__builtin_isinf_sign:
146 case Builtin::BI__builtin_isnan:
147 case Builtin::BI__builtin_isnormal:
148 if (SemaBuiltinUnaryFP(TheCall))
151 case Builtin::BI__builtin_return_address:
152 case Builtin::BI__builtin_frame_address:
153 if (SemaBuiltinStackAddress(TheCall))
156 case Builtin::BI__builtin_eh_return_data_regno:
157 if (SemaBuiltinEHReturnDataRegNo(TheCall))
160 case Builtin::BI__builtin_shufflevector:
161 return SemaBuiltinShuffleVector(TheCall);
162 // TheCall will be freed by the smart pointer here, but that's fine, since
163 // SemaBuiltinShuffleVector guts it, but then doesn't release it.
164 case Builtin::BI__builtin_prefetch:
165 if (SemaBuiltinPrefetch(TheCall))
168 case Builtin::BI__builtin_object_size:
169 if (SemaBuiltinObjectSize(TheCall))
172 case Builtin::BI__builtin_longjmp:
173 if (SemaBuiltinLongjmp(TheCall))
176 case Builtin::BI__sync_fetch_and_add:
177 case Builtin::BI__sync_fetch_and_sub:
178 case Builtin::BI__sync_fetch_and_or:
179 case Builtin::BI__sync_fetch_and_and:
180 case Builtin::BI__sync_fetch_and_xor:
181 case Builtin::BI__sync_fetch_and_nand:
182 case Builtin::BI__sync_add_and_fetch:
183 case Builtin::BI__sync_sub_and_fetch:
184 case Builtin::BI__sync_and_and_fetch:
185 case Builtin::BI__sync_or_and_fetch:
186 case Builtin::BI__sync_xor_and_fetch:
187 case Builtin::BI__sync_nand_and_fetch:
188 case Builtin::BI__sync_val_compare_and_swap:
189 case Builtin::BI__sync_bool_compare_and_swap:
190 case Builtin::BI__sync_lock_test_and_set:
191 case Builtin::BI__sync_lock_release:
192 if (SemaBuiltinAtomicOverloaded(TheCall))
197 return move(TheCallResult);
200 /// CheckFunctionCall - Check a direct function call for various correctness
201 /// and safety properties not strictly enforced by the C type system.
202 bool Sema::CheckFunctionCall(FunctionDecl *FDecl, CallExpr *TheCall) {
203 // Get the IdentifierInfo* for the called function.
204 IdentifierInfo *FnInfo = FDecl->getIdentifier();
206 // None of the checks below are needed for functions that don't have
207 // simple names (e.g., C++ conversion functions).
211 // FIXME: This mechanism should be abstracted to be less fragile and
212 // more efficient. For example, just map function ids to custom
216 if (const FormatAttr *Format = FDecl->getAttr<FormatAttr>()) {
217 if (CheckablePrintfAttr(Format, TheCall)) {
218 bool HasVAListArg = Format->getFirstArg() == 0;
220 if (const FunctionProtoType *Proto
221 = FDecl->getType()->getAs<FunctionProtoType>())
222 HasVAListArg = !Proto->isVariadic();
224 CheckPrintfArguments(TheCall, HasVAListArg, Format->getFormatIdx() - 1,
225 HasVAListArg ? 0 : Format->getFirstArg() - 1);
229 for (const NonNullAttr *NonNull = FDecl->getAttr<NonNullAttr>(); NonNull;
230 NonNull = NonNull->getNext<NonNullAttr>())
231 CheckNonNullArguments(NonNull, TheCall);
236 bool Sema::CheckBlockCall(NamedDecl *NDecl, CallExpr *TheCall) {
238 const FormatAttr *Format = NDecl->getAttr<FormatAttr>();
242 const VarDecl *V = dyn_cast<VarDecl>(NDecl);
246 QualType Ty = V->getType();
247 if (!Ty->isBlockPointerType())
250 if (!CheckablePrintfAttr(Format, TheCall))
253 bool HasVAListArg = Format->getFirstArg() == 0;
255 const FunctionType *FT =
256 Ty->getAs<BlockPointerType>()->getPointeeType()->getAs<FunctionType>();
257 if (const FunctionProtoType *Proto = dyn_cast<FunctionProtoType>(FT))
258 HasVAListArg = !Proto->isVariadic();
260 CheckPrintfArguments(TheCall, HasVAListArg, Format->getFormatIdx() - 1,
261 HasVAListArg ? 0 : Format->getFirstArg() - 1);
266 /// SemaBuiltinAtomicOverloaded - We have a call to a function like
267 /// __sync_fetch_and_add, which is an overloaded function based on the pointer
268 /// type of its first argument. The main ActOnCallExpr routines have already
269 /// promoted the types of arguments because all of these calls are prototyped as
272 /// This function goes through and does final semantic checking for these
274 bool Sema::SemaBuiltinAtomicOverloaded(CallExpr *TheCall) {
275 DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts());
276 FunctionDecl *FDecl = cast<FunctionDecl>(DRE->getDecl());
278 // Ensure that we have at least one argument to do type inference from.
279 if (TheCall->getNumArgs() < 1)
280 return Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args)
281 << 0 << TheCall->getCallee()->getSourceRange();
283 // Inspect the first argument of the atomic builtin. This should always be
284 // a pointer type, whose element is an integral scalar or pointer type.
285 // Because it is a pointer type, we don't have to worry about any implicit
287 Expr *FirstArg = TheCall->getArg(0);
288 if (!FirstArg->getType()->isPointerType())
289 return Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer)
290 << FirstArg->getType() << FirstArg->getSourceRange();
292 QualType ValType = FirstArg->getType()->getAs<PointerType>()->getPointeeType();
293 if (!ValType->isIntegerType() && !ValType->isPointerType() &&
294 !ValType->isBlockPointerType())
295 return Diag(DRE->getLocStart(),
296 diag::err_atomic_builtin_must_be_pointer_intptr)
297 << FirstArg->getType() << FirstArg->getSourceRange();
299 // We need to figure out which concrete builtin this maps onto. For example,
300 // __sync_fetch_and_add with a 2 byte object turns into
301 // __sync_fetch_and_add_2.
302 #define BUILTIN_ROW(x) \
303 { Builtin::BI##x##_1, Builtin::BI##x##_2, Builtin::BI##x##_4, \
304 Builtin::BI##x##_8, Builtin::BI##x##_16 }
306 static const unsigned BuiltinIndices[][5] = {
307 BUILTIN_ROW(__sync_fetch_and_add),
308 BUILTIN_ROW(__sync_fetch_and_sub),
309 BUILTIN_ROW(__sync_fetch_and_or),
310 BUILTIN_ROW(__sync_fetch_and_and),
311 BUILTIN_ROW(__sync_fetch_and_xor),
312 BUILTIN_ROW(__sync_fetch_and_nand),
314 BUILTIN_ROW(__sync_add_and_fetch),
315 BUILTIN_ROW(__sync_sub_and_fetch),
316 BUILTIN_ROW(__sync_and_and_fetch),
317 BUILTIN_ROW(__sync_or_and_fetch),
318 BUILTIN_ROW(__sync_xor_and_fetch),
319 BUILTIN_ROW(__sync_nand_and_fetch),
321 BUILTIN_ROW(__sync_val_compare_and_swap),
322 BUILTIN_ROW(__sync_bool_compare_and_swap),
323 BUILTIN_ROW(__sync_lock_test_and_set),
324 BUILTIN_ROW(__sync_lock_release)
328 // Determine the index of the size.
330 switch (Context.getTypeSizeInChars(ValType).getQuantity()) {
331 case 1: SizeIndex = 0; break;
332 case 2: SizeIndex = 1; break;
333 case 4: SizeIndex = 2; break;
334 case 8: SizeIndex = 3; break;
335 case 16: SizeIndex = 4; break;
337 return Diag(DRE->getLocStart(), diag::err_atomic_builtin_pointer_size)
338 << FirstArg->getType() << FirstArg->getSourceRange();
341 // Each of these builtins has one pointer argument, followed by some number of
342 // values (0, 1 or 2) followed by a potentially empty varags list of stuff
343 // that we ignore. Find out which row of BuiltinIndices to read from as well
344 // as the number of fixed args.
345 unsigned BuiltinID = FDecl->getBuiltinID();
346 unsigned BuiltinIndex, NumFixed = 1;
348 default: assert(0 && "Unknown overloaded atomic builtin!");
349 case Builtin::BI__sync_fetch_and_add: BuiltinIndex = 0; break;
350 case Builtin::BI__sync_fetch_and_sub: BuiltinIndex = 1; break;
351 case Builtin::BI__sync_fetch_and_or: BuiltinIndex = 2; break;
352 case Builtin::BI__sync_fetch_and_and: BuiltinIndex = 3; break;
353 case Builtin::BI__sync_fetch_and_xor: BuiltinIndex = 4; break;
354 case Builtin::BI__sync_fetch_and_nand:BuiltinIndex = 5; break;
356 case Builtin::BI__sync_add_and_fetch: BuiltinIndex = 6; break;
357 case Builtin::BI__sync_sub_and_fetch: BuiltinIndex = 7; break;
358 case Builtin::BI__sync_and_and_fetch: BuiltinIndex = 8; break;
359 case Builtin::BI__sync_or_and_fetch: BuiltinIndex = 9; break;
360 case Builtin::BI__sync_xor_and_fetch: BuiltinIndex =10; break;
361 case Builtin::BI__sync_nand_and_fetch:BuiltinIndex =11; break;
363 case Builtin::BI__sync_val_compare_and_swap:
367 case Builtin::BI__sync_bool_compare_and_swap:
371 case Builtin::BI__sync_lock_test_and_set: BuiltinIndex = 14; break;
372 case Builtin::BI__sync_lock_release:
378 // Now that we know how many fixed arguments we expect, first check that we
379 // have at least that many.
380 if (TheCall->getNumArgs() < 1+NumFixed)
381 return Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args)
382 << 0 << TheCall->getCallee()->getSourceRange();
385 // Get the decl for the concrete builtin from this, we can tell what the
386 // concrete integer type we should convert to is.
387 unsigned NewBuiltinID = BuiltinIndices[BuiltinIndex][SizeIndex];
388 const char *NewBuiltinName = Context.BuiltinInfo.GetName(NewBuiltinID);
389 IdentifierInfo *NewBuiltinII = PP.getIdentifierInfo(NewBuiltinName);
390 FunctionDecl *NewBuiltinDecl =
391 cast<FunctionDecl>(LazilyCreateBuiltin(NewBuiltinII, NewBuiltinID,
392 TUScope, false, DRE->getLocStart()));
393 const FunctionProtoType *BuiltinFT =
394 NewBuiltinDecl->getType()->getAs<FunctionProtoType>();
395 ValType = BuiltinFT->getArgType(0)->getAs<PointerType>()->getPointeeType();
397 // If the first type needs to be converted (e.g. void** -> int*), do it now.
398 if (BuiltinFT->getArgType(0) != FirstArg->getType()) {
399 ImpCastExprToType(FirstArg, BuiltinFT->getArgType(0), CastExpr::CK_BitCast);
400 TheCall->setArg(0, FirstArg);
403 // Next, walk the valid ones promoting to the right type.
404 for (unsigned i = 0; i != NumFixed; ++i) {
405 Expr *Arg = TheCall->getArg(i+1);
407 // If the argument is an implicit cast, then there was a promotion due to
408 // "...", just remove it now.
409 if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(Arg)) {
410 Arg = ICE->getSubExpr();
412 ICE->Destroy(Context);
413 TheCall->setArg(i+1, Arg);
416 // GCC does an implicit conversion to the pointer or integer ValType. This
417 // can fail in some cases (1i -> int**), check for this error case now.
418 CastExpr::CastKind Kind = CastExpr::CK_Unknown;
419 CXXMethodDecl *ConversionDecl = 0;
420 if (CheckCastTypes(Arg->getSourceRange(), ValType, Arg, Kind,
424 // Okay, we have something that *can* be converted to the right type. Check
425 // to see if there is a potentially weird extension going on here. This can
426 // happen when you do an atomic operation on something like an char* and
427 // pass in 42. The 42 gets converted to char. This is even more strange
428 // for things like 45.123 -> char, etc.
429 // FIXME: Do this check.
430 ImpCastExprToType(Arg, ValType, Kind, /*isLvalue=*/false);
431 TheCall->setArg(i+1, Arg);
434 // Switch the DeclRefExpr to refer to the new decl.
435 DRE->setDecl(NewBuiltinDecl);
436 DRE->setType(NewBuiltinDecl->getType());
438 // Set the callee in the CallExpr.
439 // FIXME: This leaks the original parens and implicit casts.
440 Expr *PromotedCall = DRE;
441 UsualUnaryConversions(PromotedCall);
442 TheCall->setCallee(PromotedCall);
445 // Change the result type of the call to match the result type of the decl.
446 TheCall->setType(NewBuiltinDecl->getResultType());
451 /// CheckObjCString - Checks that the argument to the builtin
452 /// CFString constructor is correct
453 /// FIXME: GCC currently emits the following warning:
454 /// "warning: input conversion stopped due to an input byte that does not
455 /// belong to the input codeset UTF-8"
456 /// Note: It might also make sense to do the UTF-16 conversion here (would
457 /// simplify the backend).
458 bool Sema::CheckObjCString(Expr *Arg) {
459 Arg = Arg->IgnoreParenCasts();
460 StringLiteral *Literal = dyn_cast<StringLiteral>(Arg);
462 if (!Literal || Literal->isWide()) {
463 Diag(Arg->getLocStart(), diag::err_cfstring_literal_not_string_constant)
464 << Arg->getSourceRange();
468 const char *Data = Literal->getStrData();
469 unsigned Length = Literal->getByteLength();
471 for (unsigned i = 0; i < Length; ++i) {
473 Diag(getLocationOfStringLiteralByte(Literal, i),
474 diag::warn_cfstring_literal_contains_nul_character)
475 << Arg->getSourceRange();
483 /// SemaBuiltinVAStart - Check the arguments to __builtin_va_start for validity.
484 /// Emit an error and return true on failure, return false on success.
485 bool Sema::SemaBuiltinVAStart(CallExpr *TheCall) {
486 Expr *Fn = TheCall->getCallee();
487 if (TheCall->getNumArgs() > 2) {
488 Diag(TheCall->getArg(2)->getLocStart(),
489 diag::err_typecheck_call_too_many_args)
490 << 0 /*function call*/ << Fn->getSourceRange()
491 << SourceRange(TheCall->getArg(2)->getLocStart(),
492 (*(TheCall->arg_end()-1))->getLocEnd());
496 if (TheCall->getNumArgs() < 2) {
497 return Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args)
498 << 0 /*function call*/;
501 // Determine whether the current function is variadic or not.
504 isVariadic = CurBlock->isVariadic;
505 else if (getCurFunctionDecl()) {
506 if (FunctionProtoType* FTP =
507 dyn_cast<FunctionProtoType>(getCurFunctionDecl()->getType()))
508 isVariadic = FTP->isVariadic();
512 isVariadic = getCurMethodDecl()->isVariadic();
516 Diag(Fn->getLocStart(), diag::err_va_start_used_in_non_variadic_function);
520 // Verify that the second argument to the builtin is the last argument of the
521 // current function or method.
522 bool SecondArgIsLastNamedArgument = false;
523 const Expr *Arg = TheCall->getArg(1)->IgnoreParenCasts();
525 if (const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(Arg)) {
526 if (const ParmVarDecl *PV = dyn_cast<ParmVarDecl>(DR->getDecl())) {
527 // FIXME: This isn't correct for methods (results in bogus warning).
528 // Get the last formal in the current function.
529 const ParmVarDecl *LastArg;
531 LastArg = *(CurBlock->TheDecl->param_end()-1);
532 else if (FunctionDecl *FD = getCurFunctionDecl())
533 LastArg = *(FD->param_end()-1);
535 LastArg = *(getCurMethodDecl()->param_end()-1);
536 SecondArgIsLastNamedArgument = PV == LastArg;
540 if (!SecondArgIsLastNamedArgument)
541 Diag(TheCall->getArg(1)->getLocStart(),
542 diag::warn_second_parameter_of_va_start_not_last_named_argument);
546 /// SemaBuiltinUnorderedCompare - Handle functions like __builtin_isgreater and
547 /// friends. This is declared to take (...), so we have to check everything.
548 bool Sema::SemaBuiltinUnorderedCompare(CallExpr *TheCall) {
549 if (TheCall->getNumArgs() < 2)
550 return Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args)
551 << 0 /*function call*/;
552 if (TheCall->getNumArgs() > 2)
553 return Diag(TheCall->getArg(2)->getLocStart(),
554 diag::err_typecheck_call_too_many_args)
555 << 0 /*function call*/
556 << SourceRange(TheCall->getArg(2)->getLocStart(),
557 (*(TheCall->arg_end()-1))->getLocEnd());
559 Expr *OrigArg0 = TheCall->getArg(0);
560 Expr *OrigArg1 = TheCall->getArg(1);
562 // Do standard promotions between the two arguments, returning their common
564 QualType Res = UsualArithmeticConversions(OrigArg0, OrigArg1, false);
566 // Make sure any conversions are pushed back into the call; this is
567 // type safe since unordered compare builtins are declared as "_Bool
569 TheCall->setArg(0, OrigArg0);
570 TheCall->setArg(1, OrigArg1);
572 if (OrigArg0->isTypeDependent() || OrigArg1->isTypeDependent())
575 // If the common type isn't a real floating type, then the arguments were
576 // invalid for this operation.
577 if (!Res->isRealFloatingType())
578 return Diag(OrigArg0->getLocStart(),
579 diag::err_typecheck_call_invalid_ordered_compare)
580 << OrigArg0->getType() << OrigArg1->getType()
581 << SourceRange(OrigArg0->getLocStart(), OrigArg1->getLocEnd());
586 /// SemaBuiltinUnorderedCompare - Handle functions like __builtin_isnan and
587 /// friends. This is declared to take (...), so we have to check everything.
588 bool Sema::SemaBuiltinUnaryFP(CallExpr *TheCall) {
589 if (TheCall->getNumArgs() < 1)
590 return Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args)
591 << 0 /*function call*/;
592 if (TheCall->getNumArgs() > 1)
593 return Diag(TheCall->getArg(1)->getLocStart(),
594 diag::err_typecheck_call_too_many_args)
595 << 0 /*function call*/
596 << SourceRange(TheCall->getArg(1)->getLocStart(),
597 (*(TheCall->arg_end()-1))->getLocEnd());
599 Expr *OrigArg = TheCall->getArg(0);
601 if (OrigArg->isTypeDependent())
604 // This operation requires a floating-point number
605 if (!OrigArg->getType()->isRealFloatingType())
606 return Diag(OrigArg->getLocStart(),
607 diag::err_typecheck_call_invalid_unary_fp)
608 << OrigArg->getType() << OrigArg->getSourceRange();
613 bool Sema::SemaBuiltinStackAddress(CallExpr *TheCall) {
614 // The signature for these builtins is exact; the only thing we need
615 // to check is that the argument is a constant.
617 if (!TheCall->getArg(0)->isTypeDependent() &&
618 !TheCall->getArg(0)->isValueDependent() &&
619 !TheCall->getArg(0)->isIntegerConstantExpr(Context, &Loc))
620 return Diag(Loc, diag::err_stack_const_level) << TheCall->getSourceRange();
625 /// SemaBuiltinShuffleVector - Handle __builtin_shufflevector.
626 // This is declared to take (...), so we have to check everything.
627 Action::OwningExprResult Sema::SemaBuiltinShuffleVector(CallExpr *TheCall) {
628 if (TheCall->getNumArgs() < 3)
629 return ExprError(Diag(TheCall->getLocEnd(),
630 diag::err_typecheck_call_too_few_args)
631 << 0 /*function call*/ << TheCall->getSourceRange());
633 unsigned numElements = std::numeric_limits<unsigned>::max();
634 if (!TheCall->getArg(0)->isTypeDependent() &&
635 !TheCall->getArg(1)->isTypeDependent()) {
636 QualType FAType = TheCall->getArg(0)->getType();
637 QualType SAType = TheCall->getArg(1)->getType();
639 if (!FAType->isVectorType() || !SAType->isVectorType()) {
640 Diag(TheCall->getLocStart(), diag::err_shufflevector_non_vector)
641 << SourceRange(TheCall->getArg(0)->getLocStart(),
642 TheCall->getArg(1)->getLocEnd());
646 if (!Context.hasSameUnqualifiedType(FAType, SAType)) {
647 Diag(TheCall->getLocStart(), diag::err_shufflevector_incompatible_vector)
648 << SourceRange(TheCall->getArg(0)->getLocStart(),
649 TheCall->getArg(1)->getLocEnd());
653 numElements = FAType->getAs<VectorType>()->getNumElements();
654 if (TheCall->getNumArgs() != numElements+2) {
655 if (TheCall->getNumArgs() < numElements+2)
656 return ExprError(Diag(TheCall->getLocEnd(),
657 diag::err_typecheck_call_too_few_args)
658 << 0 /*function call*/ << TheCall->getSourceRange());
659 return ExprError(Diag(TheCall->getLocEnd(),
660 diag::err_typecheck_call_too_many_args)
661 << 0 /*function call*/ << TheCall->getSourceRange());
665 for (unsigned i = 2; i < TheCall->getNumArgs(); i++) {
666 if (TheCall->getArg(i)->isTypeDependent() ||
667 TheCall->getArg(i)->isValueDependent())
670 llvm::APSInt Result(32);
671 if (!TheCall->getArg(i)->isIntegerConstantExpr(Result, Context))
672 return ExprError(Diag(TheCall->getLocStart(),
673 diag::err_shufflevector_nonconstant_argument)
674 << TheCall->getArg(i)->getSourceRange());
676 if (Result.getActiveBits() > 64 || Result.getZExtValue() >= numElements*2)
677 return ExprError(Diag(TheCall->getLocStart(),
678 diag::err_shufflevector_argument_too_large)
679 << TheCall->getArg(i)->getSourceRange());
682 llvm::SmallVector<Expr*, 32> exprs;
684 for (unsigned i = 0, e = TheCall->getNumArgs(); i != e; i++) {
685 exprs.push_back(TheCall->getArg(i));
686 TheCall->setArg(i, 0);
689 return Owned(new (Context) ShuffleVectorExpr(Context, exprs.begin(),
690 exprs.size(), exprs[0]->getType(),
691 TheCall->getCallee()->getLocStart(),
692 TheCall->getRParenLoc()));
695 /// SemaBuiltinPrefetch - Handle __builtin_prefetch.
696 // This is declared to take (const void*, ...) and can take two
697 // optional constant int args.
698 bool Sema::SemaBuiltinPrefetch(CallExpr *TheCall) {
699 unsigned NumArgs = TheCall->getNumArgs();
702 return Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_many_args)
703 << 0 /*function call*/ << TheCall->getSourceRange();
705 // Argument 0 is checked for us and the remaining arguments must be
706 // constant integers.
707 for (unsigned i = 1; i != NumArgs; ++i) {
708 Expr *Arg = TheCall->getArg(i);
709 if (Arg->isTypeDependent())
712 if (!Arg->getType()->isIntegralType())
713 return Diag(TheCall->getLocStart(), diag::err_prefetch_invalid_arg_type)
714 << Arg->getSourceRange();
716 ImpCastExprToType(Arg, Context.IntTy, CastExpr::CK_IntegralCast);
717 TheCall->setArg(i, Arg);
719 if (Arg->isValueDependent())
723 if (!Arg->isIntegerConstantExpr(Result, Context))
724 return Diag(TheCall->getLocStart(), diag::err_prefetch_invalid_arg_ice)
725 << SourceRange(Arg->getLocStart(), Arg->getLocEnd());
727 // FIXME: gcc issues a warning and rewrites these to 0. These
728 // seems especially odd for the third argument since the default
731 if (Result.getLimitedValue() > 1)
732 return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range)
733 << "0" << "1" << Arg->getSourceRange();
735 if (Result.getLimitedValue() > 3)
736 return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range)
737 << "0" << "3" << Arg->getSourceRange();
744 /// SemaBuiltinEHReturnDataRegNo - Handle __builtin_eh_return_data_regno, the
745 /// operand must be an integer constant.
746 bool Sema::SemaBuiltinEHReturnDataRegNo(CallExpr *TheCall) {
748 if (!TheCall->getArg(0)->isIntegerConstantExpr(Result, Context))
749 return Diag(TheCall->getLocStart(), diag::err_expr_not_ice)
750 << TheCall->getArg(0)->getSourceRange();
756 /// SemaBuiltinObjectSize - Handle __builtin_object_size(void *ptr,
757 /// int type). This simply type checks that type is one of the defined
759 // For compatability check 0-3, llvm only handles 0 and 2.
760 bool Sema::SemaBuiltinObjectSize(CallExpr *TheCall) {
761 Expr *Arg = TheCall->getArg(1);
762 if (Arg->isTypeDependent())
765 QualType ArgType = Arg->getType();
766 const BuiltinType *BT = ArgType->getAs<BuiltinType>();
767 llvm::APSInt Result(32);
768 if (!BT || BT->getKind() != BuiltinType::Int)
769 return Diag(TheCall->getLocStart(), diag::err_object_size_invalid_argument)
770 << SourceRange(Arg->getLocStart(), Arg->getLocEnd());
772 if (Arg->isValueDependent())
775 if (!Arg->isIntegerConstantExpr(Result, Context)) {
776 return Diag(TheCall->getLocStart(), diag::err_object_size_invalid_argument)
777 << SourceRange(Arg->getLocStart(), Arg->getLocEnd());
780 if (Result.getSExtValue() < 0 || Result.getSExtValue() > 3) {
781 return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range)
782 << "0" << "3" << SourceRange(Arg->getLocStart(), Arg->getLocEnd());
788 /// SemaBuiltinLongjmp - Handle __builtin_longjmp(void *env[5], int val).
789 /// This checks that val is a constant 1.
790 bool Sema::SemaBuiltinLongjmp(CallExpr *TheCall) {
791 Expr *Arg = TheCall->getArg(1);
792 if (Arg->isTypeDependent() || Arg->isValueDependent())
795 llvm::APSInt Result(32);
796 if (!Arg->isIntegerConstantExpr(Result, Context) || Result != 1)
797 return Diag(TheCall->getLocStart(), diag::err_builtin_longjmp_invalid_val)
798 << SourceRange(Arg->getLocStart(), Arg->getLocEnd());
803 // Handle i > 1 ? "x" : "y", recursivelly
804 bool Sema::SemaCheckStringLiteral(const Expr *E, const CallExpr *TheCall,
806 unsigned format_idx, unsigned firstDataArg) {
807 if (E->isTypeDependent() || E->isValueDependent())
810 switch (E->getStmtClass()) {
811 case Stmt::ConditionalOperatorClass: {
812 const ConditionalOperator *C = cast<ConditionalOperator>(E);
813 return SemaCheckStringLiteral(C->getTrueExpr(), TheCall,
814 HasVAListArg, format_idx, firstDataArg)
815 && SemaCheckStringLiteral(C->getRHS(), TheCall,
816 HasVAListArg, format_idx, firstDataArg);
819 case Stmt::ImplicitCastExprClass: {
820 const ImplicitCastExpr *Expr = cast<ImplicitCastExpr>(E);
821 return SemaCheckStringLiteral(Expr->getSubExpr(), TheCall, HasVAListArg,
822 format_idx, firstDataArg);
825 case Stmt::ParenExprClass: {
826 const ParenExpr *Expr = cast<ParenExpr>(E);
827 return SemaCheckStringLiteral(Expr->getSubExpr(), TheCall, HasVAListArg,
828 format_idx, firstDataArg);
831 case Stmt::DeclRefExprClass: {
832 const DeclRefExpr *DR = cast<DeclRefExpr>(E);
834 // As an exception, do not flag errors for variables binding to
835 // const string literals.
836 if (const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl())) {
837 bool isConstant = false;
838 QualType T = DR->getType();
840 if (const ArrayType *AT = Context.getAsArrayType(T)) {
841 isConstant = AT->getElementType().isConstant(Context);
842 } else if (const PointerType *PT = T->getAs<PointerType>()) {
843 isConstant = T.isConstant(Context) &&
844 PT->getPointeeType().isConstant(Context);
848 const VarDecl *Def = 0;
849 if (const Expr *Init = VD->getDefinition(Def))
850 return SemaCheckStringLiteral(Init, TheCall,
851 HasVAListArg, format_idx, firstDataArg);
854 // For vprintf* functions (i.e., HasVAListArg==true), we add a
855 // special check to see if the format string is a function parameter
856 // of the function calling the printf function. If the function
857 // has an attribute indicating it is a printf-like function, then we
858 // should suppress warnings concerning non-literals being used in a call
859 // to a vprintf function. For example:
862 // logmessage(char const *fmt __attribute__ (format (printf, 1, 2)), ...){
864 // va_start(ap, fmt);
865 // vprintf(fmt, ap); // Do NOT emit a warning about "fmt".
869 // FIXME: We don't have full attribute support yet, so just check to see
870 // if the argument is a DeclRefExpr that references a parameter. We'll
871 // add proper support for checking the attribute later.
873 if (isa<ParmVarDecl>(VD))
880 case Stmt::CallExprClass: {
881 const CallExpr *CE = cast<CallExpr>(E);
882 if (const ImplicitCastExpr *ICE
883 = dyn_cast<ImplicitCastExpr>(CE->getCallee())) {
884 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(ICE->getSubExpr())) {
885 if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(DRE->getDecl())) {
886 if (const FormatArgAttr *FA = FD->getAttr<FormatArgAttr>()) {
887 unsigned ArgIndex = FA->getFormatIdx();
888 const Expr *Arg = CE->getArg(ArgIndex - 1);
890 return SemaCheckStringLiteral(Arg, TheCall, HasVAListArg,
891 format_idx, firstDataArg);
899 case Stmt::ObjCStringLiteralClass:
900 case Stmt::StringLiteralClass: {
901 const StringLiteral *StrE = NULL;
903 if (const ObjCStringLiteral *ObjCFExpr = dyn_cast<ObjCStringLiteral>(E))
904 StrE = ObjCFExpr->getString();
906 StrE = cast<StringLiteral>(E);
909 CheckPrintfString(StrE, E, TheCall, HasVAListArg, format_idx,
923 Sema::CheckNonNullArguments(const NonNullAttr *NonNull,
924 const CallExpr *TheCall) {
925 for (NonNullAttr::iterator i = NonNull->begin(), e = NonNull->end();
927 const Expr *ArgExpr = TheCall->getArg(*i);
928 if (ArgExpr->isNullPointerConstant(Context,
929 Expr::NPC_ValueDependentIsNotNull))
930 Diag(TheCall->getCallee()->getLocStart(), diag::warn_null_arg)
931 << ArgExpr->getSourceRange();
935 /// CheckPrintfArguments - Check calls to printf (and similar functions) for
936 /// correct use of format strings.
938 /// HasVAListArg - A predicate indicating whether the printf-like
939 /// function is passed an explicit va_arg argument (e.g., vprintf)
941 /// format_idx - The index into Args for the format string.
943 /// Improper format strings to functions in the printf family can be
944 /// the source of bizarre bugs and very serious security holes. A
945 /// good source of information is available in the following paper
946 /// (which includes additional references):
948 /// FormatGuard: Automatic Protection From printf Format String
949 /// Vulnerabilities, Proceedings of the 10th USENIX Security Symposium, 2001.
951 /// Functionality implemented:
953 /// We can statically check the following properties for string
954 /// literal format strings for non v.*printf functions (where the
955 /// arguments are passed directly):
957 /// (1) Are the number of format conversions equal to the number of
960 /// (2) Does each format conversion correctly match the type of the
961 /// corresponding data argument? (TODO)
963 /// Moreover, for all printf functions we can:
965 /// (3) Check for a missing format string (when not caught by type checking).
967 /// (4) Check for no-operation flags; e.g. using "#" with format
968 /// conversion 'c' (TODO)
970 /// (5) Check the use of '%n', a major source of security holes.
972 /// (6) Check for malformed format conversions that don't specify anything.
974 /// (7) Check for empty format strings. e.g: printf("");
976 /// (8) Check that the format string is a wide literal.
978 /// All of these checks can be done by parsing the format string.
980 /// For now, we ONLY do (1), (3), (5), (6), (7), and (8).
982 Sema::CheckPrintfArguments(const CallExpr *TheCall, bool HasVAListArg,
983 unsigned format_idx, unsigned firstDataArg) {
984 const Expr *Fn = TheCall->getCallee();
986 // The way the format attribute works in GCC, the implicit this argument
987 // of member functions is counted. However, it doesn't appear in our own
988 // lists, so decrement format_idx in that case.
989 if (isa<CXXMemberCallExpr>(TheCall)) {
990 // Catch a format attribute mistakenly referring to the object argument.
994 if(firstDataArg != 0)
998 // CHECK: printf-like function is called with no format string.
999 if (format_idx >= TheCall->getNumArgs()) {
1000 Diag(TheCall->getRParenLoc(), diag::warn_printf_missing_format_string)
1001 << Fn->getSourceRange();
1005 const Expr *OrigFormatExpr = TheCall->getArg(format_idx)->IgnoreParenCasts();
1007 // CHECK: format string is not a string literal.
1009 // Dynamically generated format strings are difficult to
1010 // automatically vet at compile time. Requiring that format strings
1011 // are string literals: (1) permits the checking of format strings by
1012 // the compiler and thereby (2) can practically remove the source of
1013 // many format string exploits.
1015 // Format string can be either ObjC string (e.g. @"%d") or
1016 // C string (e.g. "%d")
1017 // ObjC string uses the same format specifiers as C string, so we can use
1018 // the same format string checking logic for both ObjC and C strings.
1019 if (SemaCheckStringLiteral(OrigFormatExpr, TheCall, HasVAListArg, format_idx,
1021 return; // Literal format string found, check done!
1023 // If there are no arguments specified, warn with -Wformat-security, otherwise
1024 // warn only with -Wformat-nonliteral.
1025 if (TheCall->getNumArgs() == format_idx+1)
1026 Diag(TheCall->getArg(format_idx)->getLocStart(),
1027 diag::warn_printf_nonliteral_noargs)
1028 << OrigFormatExpr->getSourceRange();
1030 Diag(TheCall->getArg(format_idx)->getLocStart(),
1031 diag::warn_printf_nonliteral)
1032 << OrigFormatExpr->getSourceRange();
1035 void Sema::CheckPrintfString(const StringLiteral *FExpr,
1036 const Expr *OrigFormatExpr,
1037 const CallExpr *TheCall, bool HasVAListArg,
1038 unsigned format_idx, unsigned firstDataArg) {
1040 const ObjCStringLiteral *ObjCFExpr =
1041 dyn_cast<ObjCStringLiteral>(OrigFormatExpr);
1043 // CHECK: is the format string a wide literal?
1044 if (FExpr->isWide()) {
1045 Diag(FExpr->getLocStart(),
1046 diag::warn_printf_format_string_is_wide_literal)
1047 << OrigFormatExpr->getSourceRange();
1051 // Str - The format string. NOTE: this is NOT null-terminated!
1052 const char *Str = FExpr->getStrData();
1054 // CHECK: empty format string?
1055 unsigned StrLen = FExpr->getByteLength();
1058 Diag(FExpr->getLocStart(), diag::warn_printf_empty_format_string)
1059 << OrigFormatExpr->getSourceRange();
1063 // We process the format string using a binary state machine. The
1064 // current state is stored in CurrentState.
1068 } CurrentState = state_OrdChr;
1070 // numConversions - The number of conversions seen so far. This is
1071 // incremented as we traverse the format string.
1072 unsigned numConversions = 0;
1074 // numDataArgs - The number of data arguments after the format
1075 // string. This can only be determined for non vprintf-like
1076 // functions. For those functions, this value is 1 (the sole
1077 // va_arg argument).
1078 unsigned numDataArgs = TheCall->getNumArgs()-firstDataArg;
1080 // Inspect the format string.
1081 unsigned StrIdx = 0;
1083 // LastConversionIdx - Index within the format string where we last saw
1084 // a '%' character that starts a new format conversion.
1085 unsigned LastConversionIdx = 0;
1087 for (; StrIdx < StrLen; ++StrIdx) {
1089 // Is the number of detected conversion conversions greater than
1090 // the number of matching data arguments? If so, stop.
1091 if (!HasVAListArg && numConversions > numDataArgs) break;
1094 if (Str[StrIdx] == '\0') {
1095 // The string returned by getStrData() is not null-terminated,
1096 // so the presence of a null character is likely an error.
1097 Diag(getLocationOfStringLiteralByte(FExpr, StrIdx),
1098 diag::warn_printf_format_string_contains_null_char)
1099 << OrigFormatExpr->getSourceRange();
1103 // Ordinary characters (not processing a format conversion).
1104 if (CurrentState == state_OrdChr) {
1105 if (Str[StrIdx] == '%') {
1106 CurrentState = state_Conversion;
1107 LastConversionIdx = StrIdx;
1112 // Seen '%'. Now processing a format conversion.
1113 switch (Str[StrIdx]) {
1114 // Handle dynamic precision or width specifier.
1118 if (!HasVAListArg) {
1119 if (numConversions > numDataArgs) {
1120 SourceLocation Loc = getLocationOfStringLiteralByte(FExpr, StrIdx);
1122 if (Str[StrIdx-1] == '.')
1123 Diag(Loc, diag::warn_printf_asterisk_precision_missing_arg)
1124 << OrigFormatExpr->getSourceRange();
1126 Diag(Loc, diag::warn_printf_asterisk_width_missing_arg)
1127 << OrigFormatExpr->getSourceRange();
1129 // Don't do any more checking. We'll just emit spurious errors.
1133 // Perform type checking on width/precision specifier.
1134 const Expr *E = TheCall->getArg(format_idx+numConversions);
1135 if (const BuiltinType *BT = E->getType()->getAs<BuiltinType>())
1136 if (BT->getKind() == BuiltinType::Int)
1139 SourceLocation Loc = getLocationOfStringLiteralByte(FExpr, StrIdx);
1141 if (Str[StrIdx-1] == '.')
1142 Diag(Loc, diag::warn_printf_asterisk_precision_wrong_type)
1143 << E->getType() << E->getSourceRange();
1145 Diag(Loc, diag::warn_printf_asterisk_width_wrong_type)
1146 << E->getType() << E->getSourceRange();
1152 // Characters which can terminate a format conversion
1153 // (e.g. "%d"). Characters that specify length modifiers or
1154 // other flags are handled by the default case below.
1156 // FIXME: additional checks will go into the following cases.
1180 CurrentState = state_OrdChr;
1184 // FIXME: Warn in situations where this isn't supported!
1185 CurrentState = state_OrdChr;
1188 // CHECK: Are we using "%n"? Issue a warning.
1191 CurrentState = state_OrdChr;
1192 SourceLocation Loc = getLocationOfStringLiteralByte(FExpr,
1195 Diag(Loc, diag::warn_printf_write_back)<<OrigFormatExpr->getSourceRange();
1201 // %@ is allowed in ObjC format strings only.
1202 if (ObjCFExpr != NULL)
1203 CurrentState = state_OrdChr;
1205 // Issue a warning: invalid format conversion.
1206 SourceLocation Loc =
1207 getLocationOfStringLiteralByte(FExpr, LastConversionIdx);
1209 Diag(Loc, diag::warn_printf_invalid_conversion)
1210 << std::string(Str+LastConversionIdx,
1211 Str+std::min(LastConversionIdx+2, StrLen))
1212 << OrigFormatExpr->getSourceRange();
1219 // Sanity check: Was the first "%" character the previous one?
1220 // If not, we will assume that we have a malformed format
1221 // conversion, and that the current "%" character is the start
1222 // of a new conversion.
1223 if (StrIdx - LastConversionIdx == 1)
1224 CurrentState = state_OrdChr;
1226 // Issue a warning: invalid format conversion.
1227 SourceLocation Loc =
1228 getLocationOfStringLiteralByte(FExpr, LastConversionIdx);
1230 Diag(Loc, diag::warn_printf_invalid_conversion)
1231 << std::string(Str+LastConversionIdx, Str+StrIdx)
1232 << OrigFormatExpr->getSourceRange();
1234 // This conversion is broken. Advance to the next format
1236 LastConversionIdx = StrIdx;
1242 // This case catches all other characters: flags, widths, etc.
1243 // We should eventually process those as well.
1248 if (CurrentState == state_Conversion) {
1249 // Issue a warning: invalid format conversion.
1250 SourceLocation Loc =
1251 getLocationOfStringLiteralByte(FExpr, LastConversionIdx);
1253 Diag(Loc, diag::warn_printf_invalid_conversion)
1254 << std::string(Str+LastConversionIdx,
1255 Str+std::min(LastConversionIdx+2, StrLen))
1256 << OrigFormatExpr->getSourceRange();
1260 if (!HasVAListArg) {
1261 // CHECK: Does the number of format conversions exceed the number
1262 // of data arguments?
1263 if (numConversions > numDataArgs) {
1264 SourceLocation Loc =
1265 getLocationOfStringLiteralByte(FExpr, LastConversionIdx);
1267 Diag(Loc, diag::warn_printf_insufficient_data_args)
1268 << OrigFormatExpr->getSourceRange();
1270 // CHECK: Does the number of data arguments exceed the number of
1271 // format conversions in the format string?
1272 else if (numConversions < numDataArgs)
1273 Diag(TheCall->getArg(format_idx+numConversions+1)->getLocStart(),
1274 diag::warn_printf_too_many_data_args)
1275 << OrigFormatExpr->getSourceRange();
1279 //===--- CHECK: Return Address of Stack Variable --------------------------===//
1281 static DeclRefExpr* EvalVal(Expr *E);
1282 static DeclRefExpr* EvalAddr(Expr* E);
1284 /// CheckReturnStackAddr - Check if a return statement returns the address
1285 /// of a stack variable.
1287 Sema::CheckReturnStackAddr(Expr *RetValExp, QualType lhsType,
1288 SourceLocation ReturnLoc) {
1290 // Perform checking for returned stack addresses.
1291 if (lhsType->isPointerType() || lhsType->isBlockPointerType()) {
1292 if (DeclRefExpr *DR = EvalAddr(RetValExp))
1293 Diag(DR->getLocStart(), diag::warn_ret_stack_addr)
1294 << DR->getDecl()->getDeclName() << RetValExp->getSourceRange();
1296 // Skip over implicit cast expressions when checking for block expressions.
1297 RetValExp = RetValExp->IgnoreParenCasts();
1299 if (BlockExpr *C = dyn_cast<BlockExpr>(RetValExp))
1300 if (C->hasBlockDeclRefExprs())
1301 Diag(C->getLocStart(), diag::err_ret_local_block)
1302 << C->getSourceRange();
1304 if (AddrLabelExpr *ALE = dyn_cast<AddrLabelExpr>(RetValExp))
1305 Diag(ALE->getLocStart(), diag::warn_ret_addr_label)
1306 << ALE->getSourceRange();
1308 } else if (lhsType->isReferenceType()) {
1309 // Perform checking for stack values returned by reference.
1310 // Check for a reference to the stack
1311 if (DeclRefExpr *DR = EvalVal(RetValExp))
1312 Diag(DR->getLocStart(), diag::warn_ret_stack_ref)
1313 << DR->getDecl()->getDeclName() << RetValExp->getSourceRange();
1317 /// EvalAddr - EvalAddr and EvalVal are mutually recursive functions that
1318 /// check if the expression in a return statement evaluates to an address
1319 /// to a location on the stack. The recursion is used to traverse the
1320 /// AST of the return expression, with recursion backtracking when we
1321 /// encounter a subexpression that (1) clearly does not lead to the address
1322 /// of a stack variable or (2) is something we cannot determine leads to
1323 /// the address of a stack variable based on such local checking.
1325 /// EvalAddr processes expressions that are pointers that are used as
1326 /// references (and not L-values). EvalVal handles all other values.
1327 /// At the base case of the recursion is a check for a DeclRefExpr* in
1328 /// the refers to a stack variable.
1330 /// This implementation handles:
1332 /// * pointer-to-pointer casts
1333 /// * implicit conversions from array references to pointers
1334 /// * taking the address of fields
1335 /// * arbitrary interplay between "&" and "*" operators
1336 /// * pointer arithmetic from an address of a stack variable
1337 /// * taking the address of an array element where the array is on the stack
1338 static DeclRefExpr* EvalAddr(Expr *E) {
1339 // We should only be called for evaluating pointer expressions.
1340 assert((E->getType()->isAnyPointerType() ||
1341 E->getType()->isBlockPointerType() ||
1342 E->getType()->isObjCQualifiedIdType()) &&
1343 "EvalAddr only works on pointers");
1345 // Our "symbolic interpreter" is just a dispatch off the currently
1346 // viewed AST node. We then recursively traverse the AST by calling
1347 // EvalAddr and EvalVal appropriately.
1348 switch (E->getStmtClass()) {
1349 case Stmt::ParenExprClass:
1350 // Ignore parentheses.
1351 return EvalAddr(cast<ParenExpr>(E)->getSubExpr());
1353 case Stmt::UnaryOperatorClass: {
1354 // The only unary operator that make sense to handle here
1355 // is AddrOf. All others don't make sense as pointers.
1356 UnaryOperator *U = cast<UnaryOperator>(E);
1358 if (U->getOpcode() == UnaryOperator::AddrOf)
1359 return EvalVal(U->getSubExpr());
1364 case Stmt::BinaryOperatorClass: {
1365 // Handle pointer arithmetic. All other binary operators are not valid
1367 BinaryOperator *B = cast<BinaryOperator>(E);
1368 BinaryOperator::Opcode op = B->getOpcode();
1370 if (op != BinaryOperator::Add && op != BinaryOperator::Sub)
1373 Expr *Base = B->getLHS();
1375 // Determine which argument is the real pointer base. It could be
1376 // the RHS argument instead of the LHS.
1377 if (!Base->getType()->isPointerType()) Base = B->getRHS();
1379 assert (Base->getType()->isPointerType());
1380 return EvalAddr(Base);
1383 // For conditional operators we need to see if either the LHS or RHS are
1384 // valid DeclRefExpr*s. If one of them is valid, we return it.
1385 case Stmt::ConditionalOperatorClass: {
1386 ConditionalOperator *C = cast<ConditionalOperator>(E);
1388 // Handle the GNU extension for missing LHS.
1389 if (Expr *lhsExpr = C->getLHS())
1390 if (DeclRefExpr* LHS = EvalAddr(lhsExpr))
1393 return EvalAddr(C->getRHS());
1396 // For casts, we need to handle conversions from arrays to
1397 // pointer values, and pointer-to-pointer conversions.
1398 case Stmt::ImplicitCastExprClass:
1399 case Stmt::CStyleCastExprClass:
1400 case Stmt::CXXFunctionalCastExprClass: {
1401 Expr* SubExpr = cast<CastExpr>(E)->getSubExpr();
1402 QualType T = SubExpr->getType();
1404 if (SubExpr->getType()->isPointerType() ||
1405 SubExpr->getType()->isBlockPointerType() ||
1406 SubExpr->getType()->isObjCQualifiedIdType())
1407 return EvalAddr(SubExpr);
1408 else if (T->isArrayType())
1409 return EvalVal(SubExpr);
1414 // C++ casts. For dynamic casts, static casts, and const casts, we
1415 // are always converting from a pointer-to-pointer, so we just blow
1416 // through the cast. In the case the dynamic cast doesn't fail (and
1417 // return NULL), we take the conservative route and report cases
1418 // where we return the address of a stack variable. For Reinterpre
1419 // FIXME: The comment about is wrong; we're not always converting
1420 // from pointer to pointer. I'm guessing that this code should also
1421 // handle references to objects.
1422 case Stmt::CXXStaticCastExprClass:
1423 case Stmt::CXXDynamicCastExprClass:
1424 case Stmt::CXXConstCastExprClass:
1425 case Stmt::CXXReinterpretCastExprClass: {
1426 Expr *S = cast<CXXNamedCastExpr>(E)->getSubExpr();
1427 if (S->getType()->isPointerType() || S->getType()->isBlockPointerType())
1433 // Everything else: we simply don't reason about them.
1440 /// EvalVal - This function is complements EvalAddr in the mutual recursion.
1441 /// See the comments for EvalAddr for more details.
1442 static DeclRefExpr* EvalVal(Expr *E) {
1444 // We should only be called for evaluating non-pointer expressions, or
1445 // expressions with a pointer type that are not used as references but instead
1446 // are l-values (e.g., DeclRefExpr with a pointer type).
1448 // Our "symbolic interpreter" is just a dispatch off the currently
1449 // viewed AST node. We then recursively traverse the AST by calling
1450 // EvalAddr and EvalVal appropriately.
1451 switch (E->getStmtClass()) {
1452 case Stmt::DeclRefExprClass: {
1453 // DeclRefExpr: the base case. When we hit a DeclRefExpr we are looking
1454 // at code that refers to a variable's name. We check if it has local
1455 // storage within the function, and if so, return the expression.
1456 DeclRefExpr *DR = cast<DeclRefExpr>(E);
1458 if (VarDecl *V = dyn_cast<VarDecl>(DR->getDecl()))
1459 if (V->hasLocalStorage() && !V->getType()->isReferenceType()) return DR;
1464 case Stmt::ParenExprClass:
1465 // Ignore parentheses.
1466 return EvalVal(cast<ParenExpr>(E)->getSubExpr());
1468 case Stmt::UnaryOperatorClass: {
1469 // The only unary operator that make sense to handle here
1470 // is Deref. All others don't resolve to a "name." This includes
1471 // handling all sorts of rvalues passed to a unary operator.
1472 UnaryOperator *U = cast<UnaryOperator>(E);
1474 if (U->getOpcode() == UnaryOperator::Deref)
1475 return EvalAddr(U->getSubExpr());
1480 case Stmt::ArraySubscriptExprClass: {
1481 // Array subscripts are potential references to data on the stack. We
1482 // retrieve the DeclRefExpr* for the array variable if it indeed
1483 // has local storage.
1484 return EvalAddr(cast<ArraySubscriptExpr>(E)->getBase());
1487 case Stmt::ConditionalOperatorClass: {
1488 // For conditional operators we need to see if either the LHS or RHS are
1489 // non-NULL DeclRefExpr's. If one is non-NULL, we return it.
1490 ConditionalOperator *C = cast<ConditionalOperator>(E);
1492 // Handle the GNU extension for missing LHS.
1493 if (Expr *lhsExpr = C->getLHS())
1494 if (DeclRefExpr *LHS = EvalVal(lhsExpr))
1497 return EvalVal(C->getRHS());
1500 // Accesses to members are potential references to data on the stack.
1501 case Stmt::MemberExprClass: {
1502 MemberExpr *M = cast<MemberExpr>(E);
1504 // Check for indirect access. We only want direct field accesses.
1506 return EvalVal(M->getBase());
1511 // Everything else: we simply don't reason about them.
1517 //===--- CHECK: Floating-Point comparisons (-Wfloat-equal) ---------------===//
1519 /// Check for comparisons of floating point operands using != and ==.
1520 /// Issue a warning if these are no self-comparisons, as they are not likely
1521 /// to do what the programmer intended.
1522 void Sema::CheckFloatComparison(SourceLocation loc, Expr* lex, Expr *rex) {
1523 bool EmitWarning = true;
1525 Expr* LeftExprSansParen = lex->IgnoreParens();
1526 Expr* RightExprSansParen = rex->IgnoreParens();
1528 // Special case: check for x == x (which is OK).
1529 // Do not emit warnings for such cases.
1530 if (DeclRefExpr* DRL = dyn_cast<DeclRefExpr>(LeftExprSansParen))
1531 if (DeclRefExpr* DRR = dyn_cast<DeclRefExpr>(RightExprSansParen))
1532 if (DRL->getDecl() == DRR->getDecl())
1533 EmitWarning = false;
1536 // Special case: check for comparisons against literals that can be exactly
1537 // represented by APFloat. In such cases, do not emit a warning. This
1538 // is a heuristic: often comparison against such literals are used to
1539 // detect if a value in a variable has not changed. This clearly can
1540 // lead to false negatives.
1542 if (FloatingLiteral* FLL = dyn_cast<FloatingLiteral>(LeftExprSansParen)) {
1544 EmitWarning = false;
1546 if (FloatingLiteral* FLR = dyn_cast<FloatingLiteral>(RightExprSansParen)){
1548 EmitWarning = false;
1552 // Check for comparisons with builtin types.
1554 if (CallExpr* CL = dyn_cast<CallExpr>(LeftExprSansParen))
1555 if (CL->isBuiltinCall(Context))
1556 EmitWarning = false;
1559 if (CallExpr* CR = dyn_cast<CallExpr>(RightExprSansParen))
1560 if (CR->isBuiltinCall(Context))
1561 EmitWarning = false;
1563 // Emit the diagnostic.
1565 Diag(loc, diag::warn_floatingpoint_eq)
1566 << lex->getSourceRange() << rex->getSourceRange();
1569 //===--- CHECK: Integer mixed-sign comparisons (-Wsign-compare) --------===//
1570 //===--- CHECK: Lossy implicit conversions (-Wconversion) --------------===//
1574 /// Structure recording the 'active' range of an integer-valued
1577 /// The number of bits active in the int.
1580 /// True if the int is known not to have negative values.
1584 IntRange(unsigned Width, bool NonNegative)
1585 : Width(Width), NonNegative(NonNegative)
1588 // Returns the range of the bool type.
1589 static IntRange forBoolType() {
1590 return IntRange(1, true);
1593 // Returns the range of an integral type.
1594 static IntRange forType(ASTContext &C, QualType T) {
1595 return forCanonicalType(C, T->getCanonicalTypeInternal().getTypePtr());
1598 // Returns the range of an integeral type based on its canonical
1600 static IntRange forCanonicalType(ASTContext &C, const Type *T) {
1601 assert(T->isCanonicalUnqualified());
1603 if (const VectorType *VT = dyn_cast<VectorType>(T))
1604 T = VT->getElementType().getTypePtr();
1605 if (const ComplexType *CT = dyn_cast<ComplexType>(T))
1606 T = CT->getElementType().getTypePtr();
1607 if (const EnumType *ET = dyn_cast<EnumType>(T))
1608 T = ET->getDecl()->getIntegerType().getTypePtr();
1610 const BuiltinType *BT = cast<BuiltinType>(T);
1611 assert(BT->isInteger());
1613 return IntRange(C.getIntWidth(QualType(T, 0)), BT->isUnsignedInteger());
1616 // Returns the supremum of two ranges: i.e. their conservative merge.
1617 static IntRange join(const IntRange &L, const IntRange &R) {
1618 return IntRange(std::max(L.Width, R.Width),
1619 L.NonNegative && R.NonNegative);
1622 // Returns the infinum of two ranges: i.e. their aggressive merge.
1623 static IntRange meet(const IntRange &L, const IntRange &R) {
1624 return IntRange(std::min(L.Width, R.Width),
1625 L.NonNegative || R.NonNegative);
1629 IntRange GetValueRange(ASTContext &C, llvm::APSInt &value, unsigned MaxWidth) {
1630 if (value.isSigned() && value.isNegative())
1631 return IntRange(value.getMinSignedBits(), false);
1633 if (value.getBitWidth() > MaxWidth)
1634 value.trunc(MaxWidth);
1636 // isNonNegative() just checks the sign bit without considering
1638 return IntRange(value.getActiveBits(), true);
1641 IntRange GetValueRange(ASTContext &C, APValue &result, QualType Ty,
1642 unsigned MaxWidth) {
1644 return GetValueRange(C, result.getInt(), MaxWidth);
1646 if (result.isVector()) {
1647 IntRange R = GetValueRange(C, result.getVectorElt(0), Ty, MaxWidth);
1648 for (unsigned i = 1, e = result.getVectorLength(); i != e; ++i) {
1649 IntRange El = GetValueRange(C, result.getVectorElt(i), Ty, MaxWidth);
1650 R = IntRange::join(R, El);
1655 if (result.isComplexInt()) {
1656 IntRange R = GetValueRange(C, result.getComplexIntReal(), MaxWidth);
1657 IntRange I = GetValueRange(C, result.getComplexIntImag(), MaxWidth);
1658 return IntRange::join(R, I);
1661 // This can happen with lossless casts to intptr_t of "based" lvalues.
1662 // Assume it might use arbitrary bits.
1663 // FIXME: The only reason we need to pass the type in here is to get
1664 // the sign right on this one case. It would be nice if APValue
1666 assert(result.isLValue());
1667 return IntRange(MaxWidth, Ty->isUnsignedIntegerType());
1670 /// Pseudo-evaluate the given integer expression, estimating the
1671 /// range of values it might take.
1673 /// \param MaxWidth - the width to which the value will be truncated
1674 IntRange GetExprRange(ASTContext &C, Expr *E, unsigned MaxWidth) {
1675 E = E->IgnoreParens();
1677 // Try a full evaluation first.
1678 Expr::EvalResult result;
1679 if (E->Evaluate(result, C))
1680 return GetValueRange(C, result.Val, E->getType(), MaxWidth);
1682 // I think we only want to look through implicit casts here; if the
1683 // user has an explicit widening cast, we should treat the value as
1684 // being of the new, wider type.
1685 if (ImplicitCastExpr *CE = dyn_cast<ImplicitCastExpr>(E)) {
1686 if (CE->getCastKind() == CastExpr::CK_NoOp)
1687 return GetExprRange(C, CE->getSubExpr(), MaxWidth);
1689 IntRange OutputTypeRange = IntRange::forType(C, CE->getType());
1691 bool isIntegerCast = (CE->getCastKind() == CastExpr::CK_IntegralCast);
1692 if (!isIntegerCast && CE->getCastKind() == CastExpr::CK_Unknown)
1693 isIntegerCast = CE->getSubExpr()->getType()->isIntegerType();
1695 // Assume that non-integer casts can span the full range of the type.
1697 return OutputTypeRange;
1700 = GetExprRange(C, CE->getSubExpr(),
1701 std::min(MaxWidth, OutputTypeRange.Width));
1703 // Bail out if the subexpr's range is as wide as the cast type.
1704 if (SubRange.Width >= OutputTypeRange.Width)
1705 return OutputTypeRange;
1707 // Otherwise, we take the smaller width, and we're non-negative if
1708 // either the output type or the subexpr is.
1709 return IntRange(SubRange.Width,
1710 SubRange.NonNegative || OutputTypeRange.NonNegative);
1713 if (ConditionalOperator *CO = dyn_cast<ConditionalOperator>(E)) {
1714 // If we can fold the condition, just take that operand.
1716 if (CO->getCond()->EvaluateAsBooleanCondition(CondResult, C))
1717 return GetExprRange(C, CondResult ? CO->getTrueExpr()
1718 : CO->getFalseExpr(),
1721 // Otherwise, conservatively merge.
1722 IntRange L = GetExprRange(C, CO->getTrueExpr(), MaxWidth);
1723 IntRange R = GetExprRange(C, CO->getFalseExpr(), MaxWidth);
1724 return IntRange::join(L, R);
1727 if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) {
1728 switch (BO->getOpcode()) {
1730 // Boolean-valued operations are single-bit and positive.
1731 case BinaryOperator::LAnd:
1732 case BinaryOperator::LOr:
1733 case BinaryOperator::LT:
1734 case BinaryOperator::GT:
1735 case BinaryOperator::LE:
1736 case BinaryOperator::GE:
1737 case BinaryOperator::EQ:
1738 case BinaryOperator::NE:
1739 return IntRange::forBoolType();
1741 // Operations with opaque sources are black-listed.
1742 case BinaryOperator::PtrMemD:
1743 case BinaryOperator::PtrMemI:
1744 return IntRange::forType(C, E->getType());
1746 // Bitwise-and uses the *infinum* of the two source ranges.
1747 case BinaryOperator::And:
1748 return IntRange::meet(GetExprRange(C, BO->getLHS(), MaxWidth),
1749 GetExprRange(C, BO->getRHS(), MaxWidth));
1751 // Left shift gets black-listed based on a judgement call.
1752 case BinaryOperator::Shl:
1753 return IntRange::forType(C, E->getType());
1755 // Right shift by a constant can narrow its left argument.
1756 case BinaryOperator::Shr: {
1757 IntRange L = GetExprRange(C, BO->getLHS(), MaxWidth);
1759 // If the shift amount is a positive constant, drop the width by
1762 if (BO->getRHS()->isIntegerConstantExpr(shift, C) &&
1763 shift.isNonNegative()) {
1764 unsigned zext = shift.getZExtValue();
1765 if (zext >= L.Width)
1766 L.Width = (L.NonNegative ? 0 : 1);
1774 // Comma acts as its right operand.
1775 case BinaryOperator::Comma:
1776 return GetExprRange(C, BO->getRHS(), MaxWidth);
1778 // Black-list pointer subtractions.
1779 case BinaryOperator::Sub:
1780 if (BO->getLHS()->getType()->isPointerType())
1781 return IntRange::forType(C, E->getType());
1788 // Treat every other operator as if it were closed on the
1789 // narrowest type that encompasses both operands.
1790 IntRange L = GetExprRange(C, BO->getLHS(), MaxWidth);
1791 IntRange R = GetExprRange(C, BO->getRHS(), MaxWidth);
1792 return IntRange::join(L, R);
1795 if (UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) {
1796 switch (UO->getOpcode()) {
1797 // Boolean-valued operations are white-listed.
1798 case UnaryOperator::LNot:
1799 return IntRange::forBoolType();
1801 // Operations with opaque sources are black-listed.
1802 case UnaryOperator::Deref:
1803 case UnaryOperator::AddrOf: // should be impossible
1804 case UnaryOperator::OffsetOf:
1805 return IntRange::forType(C, E->getType());
1808 return GetExprRange(C, UO->getSubExpr(), MaxWidth);
1812 FieldDecl *BitField = E->getBitField();
1814 llvm::APSInt BitWidthAP = BitField->getBitWidth()->EvaluateAsInt(C);
1815 unsigned BitWidth = BitWidthAP.getZExtValue();
1817 return IntRange(BitWidth, BitField->getType()->isUnsignedIntegerType());
1820 return IntRange::forType(C, E->getType());
1823 /// Checks whether the given value, which currently has the given
1824 /// source semantics, has the same value when coerced through the
1825 /// target semantics.
1826 bool IsSameFloatAfterCast(const llvm::APFloat &value,
1827 const llvm::fltSemantics &Src,
1828 const llvm::fltSemantics &Tgt) {
1829 llvm::APFloat truncated = value;
1832 truncated.convert(Src, llvm::APFloat::rmNearestTiesToEven, &ignored);
1833 truncated.convert(Tgt, llvm::APFloat::rmNearestTiesToEven, &ignored);
1835 return truncated.bitwiseIsEqual(value);
1838 /// Checks whether the given value, which currently has the given
1839 /// source semantics, has the same value when coerced through the
1840 /// target semantics.
1842 /// The value might be a vector of floats (or a complex number).
1843 bool IsSameFloatAfterCast(const APValue &value,
1844 const llvm::fltSemantics &Src,
1845 const llvm::fltSemantics &Tgt) {
1846 if (value.isFloat())
1847 return IsSameFloatAfterCast(value.getFloat(), Src, Tgt);
1849 if (value.isVector()) {
1850 for (unsigned i = 0, e = value.getVectorLength(); i != e; ++i)
1851 if (!IsSameFloatAfterCast(value.getVectorElt(i), Src, Tgt))
1856 assert(value.isComplexFloat());
1857 return (IsSameFloatAfterCast(value.getComplexFloatReal(), Src, Tgt) &&
1858 IsSameFloatAfterCast(value.getComplexFloatImag(), Src, Tgt));
1861 } // end anonymous namespace
1863 /// \brief Implements -Wsign-compare.
1865 /// \param lex the left-hand expression
1866 /// \param rex the right-hand expression
1867 /// \param OpLoc the location of the joining operator
1868 /// \param Equality whether this is an "equality-like" join, which
1869 /// suppresses the warning in some cases
1870 void Sema::CheckSignCompare(Expr *lex, Expr *rex, SourceLocation OpLoc,
1871 const PartialDiagnostic &PD, bool Equality) {
1872 // Don't warn if we're in an unevaluated context.
1873 if (ExprEvalContexts.back().Context == Unevaluated)
1876 // If either expression is value-dependent, don't warn. We'll get another
1877 // chance at instantiation time.
1878 if (lex->isValueDependent() || rex->isValueDependent())
1881 QualType lt = lex->getType(), rt = rex->getType();
1883 // Only warn if both operands are integral.
1884 if (!lt->isIntegerType() || !rt->isIntegerType())
1887 // In C, the width of a bitfield determines its type, and the
1888 // declared type only contributes the signedness. This duplicates
1889 // the work that will later be done by UsualUnaryConversions.
1890 // Eventually, this check will be reorganized in a way that avoids
1891 // this duplication.
1892 if (!getLangOptions().CPlusPlus) {
1894 tmp = Context.isPromotableBitField(lex);
1895 if (!tmp.isNull()) lt = tmp;
1896 tmp = Context.isPromotableBitField(rex);
1897 if (!tmp.isNull()) rt = tmp;
1900 // The rule is that the signed operand becomes unsigned, so isolate the
1902 Expr *signedOperand = lex, *unsignedOperand = rex;
1903 QualType signedType = lt, unsignedType = rt;
1904 if (lt->isSignedIntegerType()) {
1905 if (rt->isSignedIntegerType()) return;
1907 if (!rt->isSignedIntegerType()) return;
1908 std::swap(signedOperand, unsignedOperand);
1909 std::swap(signedType, unsignedType);
1912 unsigned unsignedWidth = Context.getIntWidth(unsignedType);
1913 unsigned signedWidth = Context.getIntWidth(signedType);
1915 // If the unsigned type is strictly smaller than the signed type,
1916 // then (1) the result type will be signed and (2) the unsigned
1917 // value will fit fully within the signed type, and thus the result
1918 // of the comparison will be exact.
1919 if (signedWidth > unsignedWidth)
1922 // Otherwise, calculate the effective ranges.
1923 IntRange signedRange = GetExprRange(Context, signedOperand, signedWidth);
1924 IntRange unsignedRange = GetExprRange(Context, unsignedOperand, unsignedWidth);
1926 // We should never be unable to prove that the unsigned operand is
1928 assert(unsignedRange.NonNegative && "unsigned range includes negative?");
1930 // If the signed operand is non-negative, then the signed->unsigned
1931 // conversion won't change it.
1932 if (signedRange.NonNegative)
1935 // For (in)equality comparisons, if the unsigned operand is a
1936 // constant which cannot collide with a overflowed signed operand,
1937 // then reinterpreting the signed operand as unsigned will not
1938 // change the result of the comparison.
1939 if (Equality && unsignedRange.Width < unsignedWidth)
1943 << lt << rt << lex->getSourceRange() << rex->getSourceRange();
1946 /// Diagnose an implicit cast; purely a helper for CheckImplicitConversion.
1947 static void DiagnoseImpCast(Sema &S, Expr *E, QualType T, unsigned diag) {
1948 S.Diag(E->getExprLoc(), diag) << E->getType() << T << E->getSourceRange();
1951 /// Implements -Wconversion.
1952 void Sema::CheckImplicitConversion(Expr *E, QualType T) {
1953 // Don't diagnose in unevaluated contexts.
1954 if (ExprEvalContexts.back().Context == Sema::Unevaluated)
1957 // Don't diagnose for value-dependent expressions.
1958 if (E->isValueDependent())
1961 const Type *Source = Context.getCanonicalType(E->getType()).getTypePtr();
1962 const Type *Target = Context.getCanonicalType(T).getTypePtr();
1964 // Never diagnose implicit casts to bool.
1965 if (Target->isSpecificBuiltinType(BuiltinType::Bool))
1968 // Strip vector types.
1969 if (isa<VectorType>(Source)) {
1970 if (!isa<VectorType>(Target))
1971 return DiagnoseImpCast(*this, E, T, diag::warn_impcast_vector_scalar);
1973 Source = cast<VectorType>(Source)->getElementType().getTypePtr();
1974 Target = cast<VectorType>(Target)->getElementType().getTypePtr();
1977 // Strip complex types.
1978 if (isa<ComplexType>(Source)) {
1979 if (!isa<ComplexType>(Target))
1980 return DiagnoseImpCast(*this, E, T, diag::warn_impcast_complex_scalar);
1982 Source = cast<ComplexType>(Source)->getElementType().getTypePtr();
1983 Target = cast<ComplexType>(Target)->getElementType().getTypePtr();
1986 const BuiltinType *SourceBT = dyn_cast<BuiltinType>(Source);
1987 const BuiltinType *TargetBT = dyn_cast<BuiltinType>(Target);
1989 // If the source is floating point...
1990 if (SourceBT && SourceBT->isFloatingPoint()) {
1991 // ...and the target is floating point...
1992 if (TargetBT && TargetBT->isFloatingPoint()) {
1993 // ...then warn if we're dropping FP rank.
1995 // Builtin FP kinds are ordered by increasing FP rank.
1996 if (SourceBT->getKind() > TargetBT->getKind()) {
1997 // Don't warn about float constants that are precisely
1998 // representable in the target type.
1999 Expr::EvalResult result;
2000 if (E->Evaluate(result, Context)) {
2001 // Value might be a float, a float vector, or a float complex.
2002 if (IsSameFloatAfterCast(result.Val,
2003 Context.getFloatTypeSemantics(QualType(TargetBT, 0)),
2004 Context.getFloatTypeSemantics(QualType(SourceBT, 0))))
2008 DiagnoseImpCast(*this, E, T, diag::warn_impcast_float_precision);
2013 // If the target is integral, always warn.
2014 if ((TargetBT && TargetBT->isInteger()))
2015 // TODO: don't warn for integer values?
2016 return DiagnoseImpCast(*this, E, T, diag::warn_impcast_float_integer);
2021 if (!Source->isIntegerType() || !Target->isIntegerType())
2024 IntRange SourceRange = GetExprRange(Context, E, Context.getIntWidth(E->getType()));
2025 IntRange TargetRange = IntRange::forCanonicalType(Context, Target);
2027 // FIXME: also signed<->unsigned?
2029 if (SourceRange.Width > TargetRange.Width) {
2030 // People want to build with -Wshorten-64-to-32 and not -Wconversion
2031 // and by god we'll let them.
2032 if (SourceRange.Width == 64 && TargetRange.Width == 32)
2033 return DiagnoseImpCast(*this, E, T, diag::warn_impcast_integer_64_32);
2034 return DiagnoseImpCast(*this, E, T, diag::warn_impcast_integer_precision);
2040 // MarkLive - Mark all the blocks reachable from e as live. Returns the total
2041 // number of blocks just marked live.
2042 static unsigned MarkLive(CFGBlock *e, llvm::BitVector &live) {
2044 std::queue<CFGBlock*> workq;
2046 live.set(e->getBlockID());
2050 while (!workq.empty()) {
2051 CFGBlock *item = workq.front();
2053 for (CFGBlock::succ_iterator I=item->succ_begin(),
2057 if ((*I) && !live[(*I)->getBlockID()]) {
2058 live.set((*I)->getBlockID());
2067 static SourceLocation GetUnreachableLoc(CFGBlock &b, SourceRange &R1,
2071 R1 = R2 = SourceRange();
2075 S = b[sn].getStmt();
2076 else if (b.getTerminator())
2077 S = b.getTerminator();
2079 return SourceLocation();
2081 switch (S->getStmtClass()) {
2082 case Expr::BinaryOperatorClass: {
2083 BinaryOperator *BO = cast<BinaryOperator>(S);
2084 if (BO->getOpcode() == BinaryOperator::Comma) {
2085 if (sn+1 < b.size())
2086 return b[sn+1].getStmt()->getLocStart();
2089 if (n->getTerminator())
2090 return n->getTerminator()->getLocStart();
2091 if (n->succ_size() != 1)
2092 return SourceLocation();
2093 n = n[0].succ_begin()[0];
2094 if (n->pred_size() != 1)
2095 return SourceLocation();
2097 return n[0][0].getStmt()->getLocStart();
2100 R1 = BO->getLHS()->getSourceRange();
2101 R2 = BO->getRHS()->getSourceRange();
2102 return BO->getOperatorLoc();
2104 case Expr::UnaryOperatorClass: {
2105 const UnaryOperator *UO = cast<UnaryOperator>(S);
2106 R1 = UO->getSubExpr()->getSourceRange();
2107 return UO->getOperatorLoc();
2109 case Expr::CompoundAssignOperatorClass: {
2110 const CompoundAssignOperator *CAO = cast<CompoundAssignOperator>(S);
2111 R1 = CAO->getLHS()->getSourceRange();
2112 R2 = CAO->getRHS()->getSourceRange();
2113 return CAO->getOperatorLoc();
2115 case Expr::ConditionalOperatorClass: {
2116 const ConditionalOperator *CO = cast<ConditionalOperator>(S);
2117 return CO->getQuestionLoc();
2119 case Expr::MemberExprClass: {
2120 const MemberExpr *ME = cast<MemberExpr>(S);
2121 R1 = ME->getSourceRange();
2122 return ME->getMemberLoc();
2124 case Expr::ArraySubscriptExprClass: {
2125 const ArraySubscriptExpr *ASE = cast<ArraySubscriptExpr>(S);
2126 R1 = ASE->getLHS()->getSourceRange();
2127 R2 = ASE->getRHS()->getSourceRange();
2128 return ASE->getRBracketLoc();
2130 case Expr::CStyleCastExprClass: {
2131 const CStyleCastExpr *CSC = cast<CStyleCastExpr>(S);
2132 R1 = CSC->getSubExpr()->getSourceRange();
2133 return CSC->getLParenLoc();
2135 case Expr::CXXFunctionalCastExprClass: {
2136 const CXXFunctionalCastExpr *CE = cast <CXXFunctionalCastExpr>(S);
2137 R1 = CE->getSubExpr()->getSourceRange();
2138 return CE->getTypeBeginLoc();
2140 case Expr::ImplicitCastExprClass:
2143 case Stmt::CXXTryStmtClass: {
2144 return cast<CXXTryStmt>(S)->getHandler(0)->getCatchLoc();
2148 R1 = S->getSourceRange();
2149 return S->getLocStart();
2152 static SourceLocation MarkLiveTop(CFGBlock *e, llvm::BitVector &live,
2153 SourceManager &SM) {
2154 std::queue<CFGBlock*> workq;
2158 SourceLocation top = GetUnreachableLoc(*e, R1, R2);
2159 bool FromMainFile = false;
2160 bool FromSystemHeader = false;
2161 bool TopValid = false;
2162 if (top.isValid()) {
2163 FromMainFile = SM.isFromMainFile(top);
2164 FromSystemHeader = SM.isInSystemHeader(top);
2168 while (!workq.empty()) {
2169 CFGBlock *item = workq.front();
2171 SourceLocation c = GetUnreachableLoc(*item, R1, R2);
2174 || (SM.isFromMainFile(c) && !FromMainFile)
2175 || (FromSystemHeader && !SM.isInSystemHeader(c))
2176 || SM.isBeforeInTranslationUnit(c, top))) {
2178 FromMainFile = SM.isFromMainFile(top);
2179 FromSystemHeader = SM.isInSystemHeader(top);
2181 live.set(item->getBlockID());
2182 for (CFGBlock::succ_iterator I=item->succ_begin(),
2186 if ((*I) && !live[(*I)->getBlockID()]) {
2187 live.set((*I)->getBlockID());
2195 static int LineCmp(const void *p1, const void *p2) {
2196 SourceLocation *Line1 = (SourceLocation *)p1;
2197 SourceLocation *Line2 = (SourceLocation *)p2;
2198 return !(*Line1 < *Line2);
2206 ErrLoc(SourceLocation l, SourceRange r1, SourceRange r2)
2207 : Loc(l), R1(r1), R2(r2) { }
2211 /// CheckUnreachable - Check for unreachable code.
2212 void Sema::CheckUnreachable(AnalysisContext &AC) {
2214 // We avoid checking when there are errors, as the CFG won't faithfully match
2216 if (getDiagnostics().hasErrorOccurred())
2218 if (Diags.getDiagnosticLevel(diag::warn_unreachable) == Diagnostic::Ignored)
2221 CFG *cfg = AC.getCFG();
2225 llvm::BitVector live(cfg->getNumBlockIDs());
2226 // Mark all live things first.
2227 count = MarkLive(&cfg->getEntry(), live);
2229 if (count == cfg->getNumBlockIDs())
2230 // If there are no dead blocks, we're done.
2235 llvm::SmallVector<ErrLoc, 24> lines;
2236 bool AddEHEdges = AC.getAddEHEdges();
2237 // First, give warnings for blocks with no predecessors, as they
2238 // can't be part of a loop.
2239 for (CFG::iterator I = cfg->begin(), E = cfg->end(); I != E; ++I) {
2241 if (!live[b.getBlockID()]) {
2242 if (b.pred_begin() == b.pred_end()) {
2243 if (!AddEHEdges && b.getTerminator()
2244 && isa<CXXTryStmt>(b.getTerminator())) {
2245 // When not adding EH edges from calls, catch clauses
2246 // can otherwise seem dead. Avoid noting them as dead.
2247 count += MarkLive(&b, live);
2250 SourceLocation c = GetUnreachableLoc(b, R1, R2);
2252 // Blocks without a location can't produce a warning, so don't mark
2253 // reachable blocks from here as live.
2254 live.set(b.getBlockID());
2258 lines.push_back(ErrLoc(c, R1, R2));
2259 // Avoid excessive errors by marking everything reachable from here
2260 count += MarkLive(&b, live);
2265 if (count < cfg->getNumBlockIDs()) {
2266 // And then give warnings for the tops of loops.
2267 for (CFG::iterator I = cfg->begin(), E = cfg->end(); I != E; ++I) {
2269 if (!live[b.getBlockID()])
2270 // Avoid excessive errors by marking everything reachable from here
2271 lines.push_back(ErrLoc(MarkLiveTop(&b, live, Context.getSourceManager()), SourceRange(), SourceRange()));
2275 llvm::array_pod_sort(lines.begin(), lines.end(), LineCmp);
2276 for (llvm::SmallVector<ErrLoc, 24>::iterator I = lines.begin(),
2280 if (I->Loc.isValid())
2281 Diag(I->Loc, diag::warn_unreachable) << I->R1 << I->R2;
2284 /// CheckFallThrough - Check that we don't fall off the end of a
2285 /// Statement that should return a value.
2287 /// \returns AlwaysFallThrough iff we always fall off the end of the statement,
2288 /// MaybeFallThrough iff we might or might not fall off the end,
2289 /// NeverFallThroughOrReturn iff we never fall off the end of the statement or
2290 /// return. We assume NeverFallThrough iff we never fall off the end of the
2291 /// statement but we may return. We assume that functions not marked noreturn
2293 Sema::ControlFlowKind Sema::CheckFallThrough(AnalysisContext &AC) {
2294 CFG *cfg = AC.getCFG();
2296 // FIXME: This should be NeverFallThrough
2297 return NeverFallThroughOrReturn;
2299 // The CFG leaves in dead things, and we don't want the dead code paths to
2300 // confuse us, so we mark all live things first.
2301 std::queue<CFGBlock*> workq;
2302 llvm::BitVector live(cfg->getNumBlockIDs());
2303 unsigned count = MarkLive(&cfg->getEntry(), live);
2305 bool AddEHEdges = AC.getAddEHEdges();
2306 if (!AddEHEdges && count != cfg->getNumBlockIDs())
2307 // When there are things remaining dead, and we didn't add EH edges
2308 // from CallExprs to the catch clauses, we have to go back and
2309 // mark them as live.
2310 for (CFG::iterator I = cfg->begin(), E = cfg->end(); I != E; ++I) {
2312 if (!live[b.getBlockID()]) {
2313 if (b.pred_begin() == b.pred_end()) {
2314 if (b.getTerminator() && isa<CXXTryStmt>(b.getTerminator()))
2315 // When not adding EH edges from calls, catch clauses
2316 // can otherwise seem dead. Avoid noting them as dead.
2317 count += MarkLive(&b, live);
2323 // Now we know what is live, we check the live precessors of the exit block
2324 // and look for fall through paths, being careful to ignore normal returns,
2325 // and exceptional paths.
2326 bool HasLiveReturn = false;
2327 bool HasFakeEdge = false;
2328 bool HasPlainEdge = false;
2329 bool HasAbnormalEdge = false;
2330 for (CFGBlock::pred_iterator I=cfg->getExit().pred_begin(),
2331 E = cfg->getExit().pred_end();
2335 if (!live[B.getBlockID()])
2337 if (B.size() == 0) {
2338 if (B.getTerminator() && isa<CXXTryStmt>(B.getTerminator())) {
2339 HasAbnormalEdge = true;
2343 // A labeled empty statement, or the entry block...
2344 HasPlainEdge = true;
2347 Stmt *S = B[B.size()-1];
2348 if (isa<ReturnStmt>(S)) {
2349 HasLiveReturn = true;
2352 if (isa<ObjCAtThrowStmt>(S)) {
2356 if (isa<CXXThrowExpr>(S)) {
2360 if (const AsmStmt *AS = dyn_cast<AsmStmt>(S)) {
2361 if (AS->isMSAsm()) {
2363 HasLiveReturn = true;
2367 if (isa<CXXTryStmt>(S)) {
2368 HasAbnormalEdge = true;
2372 bool NoReturnEdge = false;
2373 if (CallExpr *C = dyn_cast<CallExpr>(S)) {
2374 if (B.succ_begin()[0] != &cfg->getExit()) {
2375 HasAbnormalEdge = true;
2378 Expr *CEE = C->getCallee()->IgnoreParenCasts();
2379 if (CEE->getType().getNoReturnAttr()) {
2380 NoReturnEdge = true;
2382 } else if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(CEE)) {
2383 ValueDecl *VD = DRE->getDecl();
2384 if (VD->hasAttr<NoReturnAttr>()) {
2385 NoReturnEdge = true;
2390 // FIXME: Add noreturn message sends.
2391 if (NoReturnEdge == false)
2392 HasPlainEdge = true;
2394 if (!HasPlainEdge) {
2396 return NeverFallThrough;
2397 return NeverFallThroughOrReturn;
2399 if (HasAbnormalEdge || HasFakeEdge || HasLiveReturn)
2400 return MaybeFallThrough;
2401 // This says AlwaysFallThrough for calls to functions that are not marked
2402 // noreturn, that don't return. If people would like this warning to be more
2403 // accurate, such functions should be marked as noreturn.
2404 return AlwaysFallThrough;
2407 /// CheckFallThroughForFunctionDef - Check that we don't fall off the end of a
2408 /// function that should return a value. Check that we don't fall off the end
2409 /// of a noreturn function. We assume that functions and blocks not marked
2410 /// noreturn will return.
2411 void Sema::CheckFallThroughForFunctionDef(Decl *D, Stmt *Body,
2412 AnalysisContext &AC) {
2413 // FIXME: Would be nice if we had a better way to control cascading errors,
2414 // but for now, avoid them. The problem is that when Parse sees:
2415 // int foo() { return a; }
2416 // The return is eaten and the Sema code sees just:
2418 // which this code would then warn about.
2419 if (getDiagnostics().hasErrorOccurred())
2422 bool ReturnsVoid = false;
2423 bool HasNoReturn = false;
2424 if (FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
2425 // If the result type of the function is a dependent type, we don't know
2426 // whether it will be void or not, so don't
2427 if (FD->getResultType()->isDependentType())
2429 if (FD->getResultType()->isVoidType())
2431 if (FD->hasAttr<NoReturnAttr>())
2433 } else if (ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D)) {
2434 if (MD->getResultType()->isVoidType())
2436 if (MD->hasAttr<NoReturnAttr>())
2440 // Short circuit for compilation speed.
2441 if ((Diags.getDiagnosticLevel(diag::warn_maybe_falloff_nonvoid_function)
2442 == Diagnostic::Ignored || ReturnsVoid)
2443 && (Diags.getDiagnosticLevel(diag::warn_noreturn_function_has_return_expr)
2444 == Diagnostic::Ignored || !HasNoReturn)
2445 && (Diags.getDiagnosticLevel(diag::warn_suggest_noreturn_block)
2446 == Diagnostic::Ignored || !ReturnsVoid))
2448 // FIXME: Function try block
2449 if (CompoundStmt *Compound = dyn_cast<CompoundStmt>(Body)) {
2450 switch (CheckFallThrough(AC)) {
2451 case MaybeFallThrough:
2453 Diag(Compound->getRBracLoc(), diag::warn_falloff_noreturn_function);
2454 else if (!ReturnsVoid)
2455 Diag(Compound->getRBracLoc(),diag::warn_maybe_falloff_nonvoid_function);
2457 case AlwaysFallThrough:
2459 Diag(Compound->getRBracLoc(), diag::warn_falloff_noreturn_function);
2460 else if (!ReturnsVoid)
2461 Diag(Compound->getRBracLoc(), diag::warn_falloff_nonvoid_function);
2463 case NeverFallThroughOrReturn:
2464 if (ReturnsVoid && !HasNoReturn)
2465 Diag(Compound->getLBracLoc(), diag::warn_suggest_noreturn_function);
2467 case NeverFallThrough:
2473 /// CheckFallThroughForBlock - Check that we don't fall off the end of a block
2474 /// that should return a value. Check that we don't fall off the end of a
2475 /// noreturn block. We assume that functions and blocks not marked noreturn
2477 void Sema::CheckFallThroughForBlock(QualType BlockTy, Stmt *Body,
2478 AnalysisContext &AC) {
2479 // FIXME: Would be nice if we had a better way to control cascading errors,
2480 // but for now, avoid them. The problem is that when Parse sees:
2481 // int foo() { return a; }
2482 // The return is eaten and the Sema code sees just:
2484 // which this code would then warn about.
2485 if (getDiagnostics().hasErrorOccurred())
2487 bool ReturnsVoid = false;
2488 bool HasNoReturn = false;
2489 if (const FunctionType *FT =BlockTy->getPointeeType()->getAs<FunctionType>()){
2490 if (FT->getResultType()->isVoidType())
2492 if (FT->getNoReturnAttr())
2496 // Short circuit for compilation speed.
2499 && (Diags.getDiagnosticLevel(diag::warn_suggest_noreturn_block)
2500 == Diagnostic::Ignored || !ReturnsVoid))
2502 // FIXME: Funtion try block
2503 if (CompoundStmt *Compound = dyn_cast<CompoundStmt>(Body)) {
2504 switch (CheckFallThrough(AC)) {
2505 case MaybeFallThrough:
2507 Diag(Compound->getRBracLoc(), diag::err_noreturn_block_has_return_expr);
2508 else if (!ReturnsVoid)
2509 Diag(Compound->getRBracLoc(), diag::err_maybe_falloff_nonvoid_block);
2511 case AlwaysFallThrough:
2513 Diag(Compound->getRBracLoc(), diag::err_noreturn_block_has_return_expr);
2514 else if (!ReturnsVoid)
2515 Diag(Compound->getRBracLoc(), diag::err_falloff_nonvoid_block);
2517 case NeverFallThroughOrReturn:
2519 Diag(Compound->getLBracLoc(), diag::warn_suggest_noreturn_block);
2521 case NeverFallThrough:
2527 /// CheckParmsForFunctionDef - Check that the parameters of the given
2528 /// function are appropriate for the definition of a function. This
2529 /// takes care of any checks that cannot be performed on the
2530 /// declaration itself, e.g., that the types of each of the function
2531 /// parameters are complete.
2532 bool Sema::CheckParmsForFunctionDef(FunctionDecl *FD) {
2533 bool HasInvalidParm = false;
2534 for (unsigned p = 0, NumParams = FD->getNumParams(); p < NumParams; ++p) {
2535 ParmVarDecl *Param = FD->getParamDecl(p);
2537 // C99 6.7.5.3p4: the parameters in a parameter type list in a
2538 // function declarator that is part of a function definition of
2539 // that function shall not have incomplete type.
2541 // This is also C++ [dcl.fct]p6.
2542 if (!Param->isInvalidDecl() &&
2543 RequireCompleteType(Param->getLocation(), Param->getType(),
2544 diag::err_typecheck_decl_incomplete_type)) {
2545 Param->setInvalidDecl();
2546 HasInvalidParm = true;
2549 // C99 6.9.1p5: If the declarator includes a parameter type list, the
2550 // declaration of each parameter shall include an identifier.
2551 if (Param->getIdentifier() == 0 &&
2552 !Param->isImplicit() &&
2553 !getLangOptions().CPlusPlus)
2554 Diag(Param->getLocation(), diag::err_parameter_name_omitted);
2557 return HasInvalidParm;