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/Preprocessor.h"
29 #include "llvm/ADT/BitVector.h"
30 #include "llvm/ADT/STLExtras.h"
31 #include "llvm/Support/raw_ostream.h"
32 #include "clang/Basic/TargetBuiltins.h"
33 #include "clang/Basic/TargetInfo.h"
34 #include "clang/Basic/ConvertUTF.h"
36 using namespace clang;
39 SourceLocation Sema::getLocationOfStringLiteralByte(const StringLiteral *SL,
40 unsigned ByteNo) const {
41 return SL->getLocationOfByte(ByteNo, PP.getSourceManager(),
42 PP.getLangOptions(), PP.getTargetInfo());
46 /// CheckablePrintfAttr - does a function call have a "printf" attribute
47 /// and arguments that merit checking?
48 bool Sema::CheckablePrintfAttr(const FormatAttr *Format, CallExpr *TheCall) {
49 if (Format->getType() == "printf") return true;
50 if (Format->getType() == "printf0") {
51 // printf0 allows null "format" string; if so don't check format/args
52 unsigned format_idx = Format->getFormatIdx() - 1;
53 // Does the index refer to the implicit object argument?
54 if (isa<CXXMemberCallExpr>(TheCall)) {
59 if (format_idx < TheCall->getNumArgs()) {
60 Expr *Format = TheCall->getArg(format_idx)->IgnoreParenCasts();
61 if (!Format->isNullPointerConstant(Context,
62 Expr::NPC_ValueDependentIsNull))
70 Sema::CheckBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) {
71 ExprResult TheCallResult(Owned(TheCall));
73 // Find out if any arguments are required to be integer constant expressions.
74 unsigned ICEArguments = 0;
75 ASTContext::GetBuiltinTypeError Error;
76 Context.GetBuiltinType(BuiltinID, Error, &ICEArguments);
77 if (Error != ASTContext::GE_None)
78 ICEArguments = 0; // Don't diagnose previously diagnosed errors.
80 // If any arguments are required to be ICE's, check and diagnose.
81 for (unsigned ArgNo = 0; ICEArguments != 0; ++ArgNo) {
82 // Skip arguments not required to be ICE's.
83 if ((ICEArguments & (1 << ArgNo)) == 0) continue;
86 if (SemaBuiltinConstantArg(TheCall, ArgNo, Result))
88 ICEArguments &= ~(1 << ArgNo);
92 case Builtin::BI__builtin___CFStringMakeConstantString:
93 assert(TheCall->getNumArgs() == 1 &&
94 "Wrong # arguments to builtin CFStringMakeConstantString");
95 if (CheckObjCString(TheCall->getArg(0)))
98 case Builtin::BI__builtin_stdarg_start:
99 case Builtin::BI__builtin_va_start:
100 if (SemaBuiltinVAStart(TheCall))
103 case Builtin::BI__builtin_isgreater:
104 case Builtin::BI__builtin_isgreaterequal:
105 case Builtin::BI__builtin_isless:
106 case Builtin::BI__builtin_islessequal:
107 case Builtin::BI__builtin_islessgreater:
108 case Builtin::BI__builtin_isunordered:
109 if (SemaBuiltinUnorderedCompare(TheCall))
112 case Builtin::BI__builtin_fpclassify:
113 if (SemaBuiltinFPClassification(TheCall, 6))
116 case Builtin::BI__builtin_isfinite:
117 case Builtin::BI__builtin_isinf:
118 case Builtin::BI__builtin_isinf_sign:
119 case Builtin::BI__builtin_isnan:
120 case Builtin::BI__builtin_isnormal:
121 if (SemaBuiltinFPClassification(TheCall, 1))
124 case Builtin::BI__builtin_shufflevector:
125 return SemaBuiltinShuffleVector(TheCall);
126 // TheCall will be freed by the smart pointer here, but that's fine, since
127 // SemaBuiltinShuffleVector guts it, but then doesn't release it.
128 case Builtin::BI__builtin_prefetch:
129 if (SemaBuiltinPrefetch(TheCall))
132 case Builtin::BI__builtin_object_size:
133 if (SemaBuiltinObjectSize(TheCall))
136 case Builtin::BI__builtin_longjmp:
137 if (SemaBuiltinLongjmp(TheCall))
140 case Builtin::BI__builtin_constant_p:
141 if (TheCall->getNumArgs() == 0)
142 return Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args)
143 << 0 /*function call*/ << 1 << 0 << TheCall->getSourceRange();
144 if (TheCall->getNumArgs() > 1)
145 return Diag(TheCall->getArg(1)->getLocStart(),
146 diag::err_typecheck_call_too_many_args)
147 << 0 /*function call*/ << 1 << TheCall->getNumArgs()
148 << TheCall->getArg(1)->getSourceRange();
150 case Builtin::BI__sync_fetch_and_add:
151 case Builtin::BI__sync_fetch_and_sub:
152 case Builtin::BI__sync_fetch_and_or:
153 case Builtin::BI__sync_fetch_and_and:
154 case Builtin::BI__sync_fetch_and_xor:
155 case Builtin::BI__sync_add_and_fetch:
156 case Builtin::BI__sync_sub_and_fetch:
157 case Builtin::BI__sync_and_and_fetch:
158 case Builtin::BI__sync_or_and_fetch:
159 case Builtin::BI__sync_xor_and_fetch:
160 case Builtin::BI__sync_val_compare_and_swap:
161 case Builtin::BI__sync_bool_compare_and_swap:
162 case Builtin::BI__sync_lock_test_and_set:
163 case Builtin::BI__sync_lock_release:
164 return SemaBuiltinAtomicOverloaded(move(TheCallResult));
167 // Since the target specific builtins for each arch overlap, only check those
168 // of the arch we are compiling for.
169 if (BuiltinID >= Builtin::FirstTSBuiltin) {
170 switch (Context.Target.getTriple().getArch()) {
171 case llvm::Triple::arm:
172 case llvm::Triple::thumb:
173 if (CheckARMBuiltinFunctionCall(BuiltinID, TheCall))
181 return move(TheCallResult);
184 // Get the valid immediate range for the specified NEON type code.
185 static unsigned RFT(unsigned t, bool shift = false) {
186 bool quad = t & 0x10;
190 return shift ? 7 : (8 << (int)quad) - 1;
192 return shift ? 15 : (4 << (int)quad) - 1;
194 return shift ? 31 : (2 << (int)quad) - 1;
196 return shift ? 63 : (1 << (int)quad) - 1;
198 assert(!shift && "cannot shift float types!");
199 return (2 << (int)quad) - 1;
201 return shift ? 7 : (8 << (int)quad) - 1;
203 return shift ? 15 : (4 << (int)quad) - 1;
205 assert(!shift && "cannot shift float types!");
206 return (4 << (int)quad) - 1;
211 bool Sema::CheckARMBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) {
217 #define GET_NEON_OVERLOAD_CHECK
218 #include "clang/Basic/arm_neon.inc"
219 #undef GET_NEON_OVERLOAD_CHECK
222 // For NEON intrinsics which are overloaded on vector element type, validate
223 // the immediate which specifies which variant to emit.
225 unsigned ArgNo = TheCall->getNumArgs()-1;
226 if (SemaBuiltinConstantArg(TheCall, ArgNo, Result))
229 TV = Result.getLimitedValue(32);
230 if ((TV > 31) || (mask & (1 << TV)) == 0)
231 return Diag(TheCall->getLocStart(), diag::err_invalid_neon_type_code)
232 << TheCall->getArg(ArgNo)->getSourceRange();
235 // For NEON intrinsics which take an immediate value as part of the
236 // instruction, range check them here.
237 unsigned i = 0, l = 0, u = 0;
239 default: return false;
240 case ARM::BI__builtin_arm_ssat: i = 1; l = 1; u = 31; break;
241 case ARM::BI__builtin_arm_usat: i = 1; u = 31; break;
242 case ARM::BI__builtin_arm_vcvtr_f:
243 case ARM::BI__builtin_arm_vcvtr_d: i = 1; u = 1; break;
244 #define GET_NEON_IMMEDIATE_CHECK
245 #include "clang/Basic/arm_neon.inc"
246 #undef GET_NEON_IMMEDIATE_CHECK
249 // Check that the immediate argument is actually a constant.
250 if (SemaBuiltinConstantArg(TheCall, i, Result))
253 // Range check against the upper/lower values for this isntruction.
254 unsigned Val = Result.getZExtValue();
255 if (Val < l || Val > (u + l))
256 return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range)
257 << l << u+l << TheCall->getArg(i)->getSourceRange();
259 // FIXME: VFP Intrinsics should error if VFP not present.
263 /// CheckFunctionCall - Check a direct function call for various correctness
264 /// and safety properties not strictly enforced by the C type system.
265 bool Sema::CheckFunctionCall(FunctionDecl *FDecl, CallExpr *TheCall) {
266 // Get the IdentifierInfo* for the called function.
267 IdentifierInfo *FnInfo = FDecl->getIdentifier();
269 // None of the checks below are needed for functions that don't have
270 // simple names (e.g., C++ conversion functions).
274 // FIXME: This mechanism should be abstracted to be less fragile and
275 // more efficient. For example, just map function ids to custom
278 // Printf and scanf checking.
279 for (specific_attr_iterator<FormatAttr>
280 i = FDecl->specific_attr_begin<FormatAttr>(),
281 e = FDecl->specific_attr_end<FormatAttr>(); i != e ; ++i) {
283 const FormatAttr *Format = *i;
284 const bool b = Format->getType() == "scanf";
285 if (b || CheckablePrintfAttr(Format, TheCall)) {
286 bool HasVAListArg = Format->getFirstArg() == 0;
287 CheckPrintfScanfArguments(TheCall, HasVAListArg,
288 Format->getFormatIdx() - 1,
289 HasVAListArg ? 0 : Format->getFirstArg() - 1,
294 for (specific_attr_iterator<NonNullAttr>
295 i = FDecl->specific_attr_begin<NonNullAttr>(),
296 e = FDecl->specific_attr_end<NonNullAttr>(); i != e; ++i) {
297 CheckNonNullArguments(*i, TheCall);
303 bool Sema::CheckBlockCall(NamedDecl *NDecl, CallExpr *TheCall) {
305 const FormatAttr *Format = NDecl->getAttr<FormatAttr>();
309 const VarDecl *V = dyn_cast<VarDecl>(NDecl);
313 QualType Ty = V->getType();
314 if (!Ty->isBlockPointerType())
317 const bool b = Format->getType() == "scanf";
318 if (!b && !CheckablePrintfAttr(Format, TheCall))
321 bool HasVAListArg = Format->getFirstArg() == 0;
322 CheckPrintfScanfArguments(TheCall, HasVAListArg, Format->getFormatIdx() - 1,
323 HasVAListArg ? 0 : Format->getFirstArg() - 1, !b);
328 /// SemaBuiltinAtomicOverloaded - We have a call to a function like
329 /// __sync_fetch_and_add, which is an overloaded function based on the pointer
330 /// type of its first argument. The main ActOnCallExpr routines have already
331 /// promoted the types of arguments because all of these calls are prototyped as
334 /// This function goes through and does final semantic checking for these
337 Sema::SemaBuiltinAtomicOverloaded(ExprResult TheCallResult) {
338 CallExpr *TheCall = (CallExpr *)TheCallResult.get();
339 DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts());
340 FunctionDecl *FDecl = cast<FunctionDecl>(DRE->getDecl());
342 // Ensure that we have at least one argument to do type inference from.
343 if (TheCall->getNumArgs() < 1) {
344 Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args_at_least)
345 << 0 << 1 << TheCall->getNumArgs()
346 << TheCall->getCallee()->getSourceRange();
350 // Inspect the first argument of the atomic builtin. This should always be
351 // a pointer type, whose element is an integral scalar or pointer type.
352 // Because it is a pointer type, we don't have to worry about any implicit
354 // FIXME: We don't allow floating point scalars as input.
355 Expr *FirstArg = TheCall->getArg(0);
356 if (!FirstArg->getType()->isPointerType()) {
357 Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer)
358 << FirstArg->getType() << FirstArg->getSourceRange();
363 FirstArg->getType()->getAs<PointerType>()->getPointeeType();
364 if (!ValType->isIntegerType() && !ValType->isAnyPointerType() &&
365 !ValType->isBlockPointerType()) {
366 Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer_intptr)
367 << FirstArg->getType() << FirstArg->getSourceRange();
371 // The majority of builtins return a value, but a few have special return
372 // types, so allow them to override appropriately below.
373 QualType ResultType = ValType;
375 // We need to figure out which concrete builtin this maps onto. For example,
376 // __sync_fetch_and_add with a 2 byte object turns into
377 // __sync_fetch_and_add_2.
378 #define BUILTIN_ROW(x) \
379 { Builtin::BI##x##_1, Builtin::BI##x##_2, Builtin::BI##x##_4, \
380 Builtin::BI##x##_8, Builtin::BI##x##_16 }
382 static const unsigned BuiltinIndices[][5] = {
383 BUILTIN_ROW(__sync_fetch_and_add),
384 BUILTIN_ROW(__sync_fetch_and_sub),
385 BUILTIN_ROW(__sync_fetch_and_or),
386 BUILTIN_ROW(__sync_fetch_and_and),
387 BUILTIN_ROW(__sync_fetch_and_xor),
389 BUILTIN_ROW(__sync_add_and_fetch),
390 BUILTIN_ROW(__sync_sub_and_fetch),
391 BUILTIN_ROW(__sync_and_and_fetch),
392 BUILTIN_ROW(__sync_or_and_fetch),
393 BUILTIN_ROW(__sync_xor_and_fetch),
395 BUILTIN_ROW(__sync_val_compare_and_swap),
396 BUILTIN_ROW(__sync_bool_compare_and_swap),
397 BUILTIN_ROW(__sync_lock_test_and_set),
398 BUILTIN_ROW(__sync_lock_release)
402 // Determine the index of the size.
404 switch (Context.getTypeSizeInChars(ValType).getQuantity()) {
405 case 1: SizeIndex = 0; break;
406 case 2: SizeIndex = 1; break;
407 case 4: SizeIndex = 2; break;
408 case 8: SizeIndex = 3; break;
409 case 16: SizeIndex = 4; break;
411 Diag(DRE->getLocStart(), diag::err_atomic_builtin_pointer_size)
412 << FirstArg->getType() << FirstArg->getSourceRange();
416 // Each of these builtins has one pointer argument, followed by some number of
417 // values (0, 1 or 2) followed by a potentially empty varags list of stuff
418 // that we ignore. Find out which row of BuiltinIndices to read from as well
419 // as the number of fixed args.
420 unsigned BuiltinID = FDecl->getBuiltinID();
421 unsigned BuiltinIndex, NumFixed = 1;
423 default: assert(0 && "Unknown overloaded atomic builtin!");
424 case Builtin::BI__sync_fetch_and_add: BuiltinIndex = 0; break;
425 case Builtin::BI__sync_fetch_and_sub: BuiltinIndex = 1; break;
426 case Builtin::BI__sync_fetch_and_or: BuiltinIndex = 2; break;
427 case Builtin::BI__sync_fetch_and_and: BuiltinIndex = 3; break;
428 case Builtin::BI__sync_fetch_and_xor: BuiltinIndex = 4; break;
430 case Builtin::BI__sync_add_and_fetch: BuiltinIndex = 5; break;
431 case Builtin::BI__sync_sub_and_fetch: BuiltinIndex = 6; break;
432 case Builtin::BI__sync_and_and_fetch: BuiltinIndex = 7; break;
433 case Builtin::BI__sync_or_and_fetch: BuiltinIndex = 8; break;
434 case Builtin::BI__sync_xor_and_fetch: BuiltinIndex = 9; break;
436 case Builtin::BI__sync_val_compare_and_swap:
440 case Builtin::BI__sync_bool_compare_and_swap:
443 ResultType = Context.BoolTy;
445 case Builtin::BI__sync_lock_test_and_set: BuiltinIndex = 12; break;
446 case Builtin::BI__sync_lock_release:
449 ResultType = Context.VoidTy;
453 // Now that we know how many fixed arguments we expect, first check that we
454 // have at least that many.
455 if (TheCall->getNumArgs() < 1+NumFixed) {
456 Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args_at_least)
457 << 0 << 1+NumFixed << TheCall->getNumArgs()
458 << TheCall->getCallee()->getSourceRange();
462 // Get the decl for the concrete builtin from this, we can tell what the
463 // concrete integer type we should convert to is.
464 unsigned NewBuiltinID = BuiltinIndices[BuiltinIndex][SizeIndex];
465 const char *NewBuiltinName = Context.BuiltinInfo.GetName(NewBuiltinID);
466 IdentifierInfo *NewBuiltinII = PP.getIdentifierInfo(NewBuiltinName);
467 FunctionDecl *NewBuiltinDecl =
468 cast<FunctionDecl>(LazilyCreateBuiltin(NewBuiltinII, NewBuiltinID,
469 TUScope, false, DRE->getLocStart()));
471 // The first argument --- the pointer --- has a fixed type; we
472 // deduce the types of the rest of the arguments accordingly. Walk
473 // the remaining arguments, converting them to the deduced value type.
474 for (unsigned i = 0; i != NumFixed; ++i) {
475 Expr *Arg = TheCall->getArg(i+1);
477 // If the argument is an implicit cast, then there was a promotion due to
478 // "...", just remove it now.
479 if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(Arg)) {
480 Arg = ICE->getSubExpr();
482 TheCall->setArg(i+1, Arg);
485 // GCC does an implicit conversion to the pointer or integer ValType. This
486 // can fail in some cases (1i -> int**), check for this error case now.
487 CastKind Kind = CK_Invalid;
488 ExprValueKind VK = VK_RValue;
489 CXXCastPath BasePath;
490 if (CheckCastTypes(Arg->getSourceRange(), ValType, Arg, Kind, VK, BasePath))
493 // Okay, we have something that *can* be converted to the right type. Check
494 // to see if there is a potentially weird extension going on here. This can
495 // happen when you do an atomic operation on something like an char* and
496 // pass in 42. The 42 gets converted to char. This is even more strange
497 // for things like 45.123 -> char, etc.
498 // FIXME: Do this check.
499 ImpCastExprToType(Arg, ValType, Kind, VK, &BasePath);
500 TheCall->setArg(i+1, Arg);
503 // Switch the DeclRefExpr to refer to the new decl.
504 DRE->setDecl(NewBuiltinDecl);
505 DRE->setType(NewBuiltinDecl->getType());
507 // Set the callee in the CallExpr.
508 // FIXME: This leaks the original parens and implicit casts.
509 Expr *PromotedCall = DRE;
510 UsualUnaryConversions(PromotedCall);
511 TheCall->setCallee(PromotedCall);
513 // Change the result type of the call to match the original value type. This
514 // is arbitrary, but the codegen for these builtins ins design to handle it
516 TheCall->setType(ResultType);
518 return move(TheCallResult);
522 /// CheckObjCString - Checks that the argument to the builtin
523 /// CFString constructor is correct
524 /// Note: It might also make sense to do the UTF-16 conversion here (would
525 /// simplify the backend).
526 bool Sema::CheckObjCString(Expr *Arg) {
527 Arg = Arg->IgnoreParenCasts();
528 StringLiteral *Literal = dyn_cast<StringLiteral>(Arg);
530 if (!Literal || Literal->isWide()) {
531 Diag(Arg->getLocStart(), diag::err_cfstring_literal_not_string_constant)
532 << Arg->getSourceRange();
536 size_t NulPos = Literal->getString().find('\0');
537 if (NulPos != llvm::StringRef::npos) {
538 Diag(getLocationOfStringLiteralByte(Literal, NulPos),
539 diag::warn_cfstring_literal_contains_nul_character)
540 << Arg->getSourceRange();
542 if (Literal->containsNonAsciiOrNull()) {
543 llvm::StringRef String = Literal->getString();
544 unsigned NumBytes = String.size();
545 llvm::SmallVector<UTF16, 128> ToBuf(NumBytes);
546 const UTF8 *FromPtr = (UTF8 *)String.data();
547 UTF16 *ToPtr = &ToBuf[0];
549 ConversionResult Result = ConvertUTF8toUTF16(&FromPtr, FromPtr + NumBytes,
550 &ToPtr, ToPtr + NumBytes,
552 // Check for conversion failure.
553 if (Result != conversionOK)
554 Diag(Arg->getLocStart(),
555 diag::warn_cfstring_truncated) << Arg->getSourceRange();
560 /// SemaBuiltinVAStart - Check the arguments to __builtin_va_start for validity.
561 /// Emit an error and return true on failure, return false on success.
562 bool Sema::SemaBuiltinVAStart(CallExpr *TheCall) {
563 Expr *Fn = TheCall->getCallee();
564 if (TheCall->getNumArgs() > 2) {
565 Diag(TheCall->getArg(2)->getLocStart(),
566 diag::err_typecheck_call_too_many_args)
567 << 0 /*function call*/ << 2 << TheCall->getNumArgs()
568 << Fn->getSourceRange()
569 << SourceRange(TheCall->getArg(2)->getLocStart(),
570 (*(TheCall->arg_end()-1))->getLocEnd());
574 if (TheCall->getNumArgs() < 2) {
575 return Diag(TheCall->getLocEnd(),
576 diag::err_typecheck_call_too_few_args_at_least)
577 << 0 /*function call*/ << 2 << TheCall->getNumArgs();
580 // Determine whether the current function is variadic or not.
581 BlockScopeInfo *CurBlock = getCurBlock();
584 isVariadic = CurBlock->TheDecl->isVariadic();
585 else if (FunctionDecl *FD = getCurFunctionDecl())
586 isVariadic = FD->isVariadic();
588 isVariadic = getCurMethodDecl()->isVariadic();
591 Diag(Fn->getLocStart(), diag::err_va_start_used_in_non_variadic_function);
595 // Verify that the second argument to the builtin is the last argument of the
596 // current function or method.
597 bool SecondArgIsLastNamedArgument = false;
598 const Expr *Arg = TheCall->getArg(1)->IgnoreParenCasts();
600 if (const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(Arg)) {
601 if (const ParmVarDecl *PV = dyn_cast<ParmVarDecl>(DR->getDecl())) {
602 // FIXME: This isn't correct for methods (results in bogus warning).
603 // Get the last formal in the current function.
604 const ParmVarDecl *LastArg;
606 LastArg = *(CurBlock->TheDecl->param_end()-1);
607 else if (FunctionDecl *FD = getCurFunctionDecl())
608 LastArg = *(FD->param_end()-1);
610 LastArg = *(getCurMethodDecl()->param_end()-1);
611 SecondArgIsLastNamedArgument = PV == LastArg;
615 if (!SecondArgIsLastNamedArgument)
616 Diag(TheCall->getArg(1)->getLocStart(),
617 diag::warn_second_parameter_of_va_start_not_last_named_argument);
621 /// SemaBuiltinUnorderedCompare - Handle functions like __builtin_isgreater and
622 /// friends. This is declared to take (...), so we have to check everything.
623 bool Sema::SemaBuiltinUnorderedCompare(CallExpr *TheCall) {
624 if (TheCall->getNumArgs() < 2)
625 return Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args)
626 << 0 << 2 << TheCall->getNumArgs()/*function call*/;
627 if (TheCall->getNumArgs() > 2)
628 return Diag(TheCall->getArg(2)->getLocStart(),
629 diag::err_typecheck_call_too_many_args)
630 << 0 /*function call*/ << 2 << TheCall->getNumArgs()
631 << SourceRange(TheCall->getArg(2)->getLocStart(),
632 (*(TheCall->arg_end()-1))->getLocEnd());
634 Expr *OrigArg0 = TheCall->getArg(0);
635 Expr *OrigArg1 = TheCall->getArg(1);
637 // Do standard promotions between the two arguments, returning their common
639 QualType Res = UsualArithmeticConversions(OrigArg0, OrigArg1, false);
641 // Make sure any conversions are pushed back into the call; this is
642 // type safe since unordered compare builtins are declared as "_Bool
644 TheCall->setArg(0, OrigArg0);
645 TheCall->setArg(1, OrigArg1);
647 if (OrigArg0->isTypeDependent() || OrigArg1->isTypeDependent())
650 // If the common type isn't a real floating type, then the arguments were
651 // invalid for this operation.
652 if (!Res->isRealFloatingType())
653 return Diag(OrigArg0->getLocStart(),
654 diag::err_typecheck_call_invalid_ordered_compare)
655 << OrigArg0->getType() << OrigArg1->getType()
656 << SourceRange(OrigArg0->getLocStart(), OrigArg1->getLocEnd());
661 /// SemaBuiltinSemaBuiltinFPClassification - Handle functions like
662 /// __builtin_isnan and friends. This is declared to take (...), so we have
663 /// to check everything. We expect the last argument to be a floating point
665 bool Sema::SemaBuiltinFPClassification(CallExpr *TheCall, unsigned NumArgs) {
666 if (TheCall->getNumArgs() < NumArgs)
667 return Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args)
668 << 0 << NumArgs << TheCall->getNumArgs()/*function call*/;
669 if (TheCall->getNumArgs() > NumArgs)
670 return Diag(TheCall->getArg(NumArgs)->getLocStart(),
671 diag::err_typecheck_call_too_many_args)
672 << 0 /*function call*/ << NumArgs << TheCall->getNumArgs()
673 << SourceRange(TheCall->getArg(NumArgs)->getLocStart(),
674 (*(TheCall->arg_end()-1))->getLocEnd());
676 Expr *OrigArg = TheCall->getArg(NumArgs-1);
678 if (OrigArg->isTypeDependent())
681 // This operation requires a non-_Complex floating-point number.
682 if (!OrigArg->getType()->isRealFloatingType())
683 return Diag(OrigArg->getLocStart(),
684 diag::err_typecheck_call_invalid_unary_fp)
685 << OrigArg->getType() << OrigArg->getSourceRange();
687 // If this is an implicit conversion from float -> double, remove it.
688 if (ImplicitCastExpr *Cast = dyn_cast<ImplicitCastExpr>(OrigArg)) {
689 Expr *CastArg = Cast->getSubExpr();
690 if (CastArg->getType()->isSpecificBuiltinType(BuiltinType::Float)) {
691 assert(Cast->getType()->isSpecificBuiltinType(BuiltinType::Double) &&
692 "promotion from float to double is the only expected cast here");
694 TheCall->setArg(NumArgs-1, CastArg);
702 /// SemaBuiltinShuffleVector - Handle __builtin_shufflevector.
703 // This is declared to take (...), so we have to check everything.
704 ExprResult Sema::SemaBuiltinShuffleVector(CallExpr *TheCall) {
705 if (TheCall->getNumArgs() < 2)
706 return ExprError(Diag(TheCall->getLocEnd(),
707 diag::err_typecheck_call_too_few_args_at_least)
708 << 0 /*function call*/ << 2 << TheCall->getNumArgs()
709 << TheCall->getSourceRange());
711 // Determine which of the following types of shufflevector we're checking:
712 // 1) unary, vector mask: (lhs, mask)
713 // 2) binary, vector mask: (lhs, rhs, mask)
714 // 3) binary, scalar mask: (lhs, rhs, index, ..., index)
715 QualType resType = TheCall->getArg(0)->getType();
716 unsigned numElements = 0;
718 if (!TheCall->getArg(0)->isTypeDependent() &&
719 !TheCall->getArg(1)->isTypeDependent()) {
720 QualType LHSType = TheCall->getArg(0)->getType();
721 QualType RHSType = TheCall->getArg(1)->getType();
723 if (!LHSType->isVectorType() || !RHSType->isVectorType()) {
724 Diag(TheCall->getLocStart(), diag::err_shufflevector_non_vector)
725 << SourceRange(TheCall->getArg(0)->getLocStart(),
726 TheCall->getArg(1)->getLocEnd());
730 numElements = LHSType->getAs<VectorType>()->getNumElements();
731 unsigned numResElements = TheCall->getNumArgs() - 2;
733 // Check to see if we have a call with 2 vector arguments, the unary shuffle
734 // with mask. If so, verify that RHS is an integer vector type with the
735 // same number of elts as lhs.
736 if (TheCall->getNumArgs() == 2) {
737 if (!RHSType->hasIntegerRepresentation() ||
738 RHSType->getAs<VectorType>()->getNumElements() != numElements)
739 Diag(TheCall->getLocStart(), diag::err_shufflevector_incompatible_vector)
740 << SourceRange(TheCall->getArg(1)->getLocStart(),
741 TheCall->getArg(1)->getLocEnd());
742 numResElements = numElements;
744 else if (!Context.hasSameUnqualifiedType(LHSType, RHSType)) {
745 Diag(TheCall->getLocStart(), diag::err_shufflevector_incompatible_vector)
746 << SourceRange(TheCall->getArg(0)->getLocStart(),
747 TheCall->getArg(1)->getLocEnd());
749 } else if (numElements != numResElements) {
750 QualType eltType = LHSType->getAs<VectorType>()->getElementType();
751 resType = Context.getVectorType(eltType, numResElements,
752 VectorType::GenericVector);
756 for (unsigned i = 2; i < TheCall->getNumArgs(); i++) {
757 if (TheCall->getArg(i)->isTypeDependent() ||
758 TheCall->getArg(i)->isValueDependent())
761 llvm::APSInt Result(32);
762 if (!TheCall->getArg(i)->isIntegerConstantExpr(Result, Context))
763 return ExprError(Diag(TheCall->getLocStart(),
764 diag::err_shufflevector_nonconstant_argument)
765 << TheCall->getArg(i)->getSourceRange());
767 if (Result.getActiveBits() > 64 || Result.getZExtValue() >= numElements*2)
768 return ExprError(Diag(TheCall->getLocStart(),
769 diag::err_shufflevector_argument_too_large)
770 << TheCall->getArg(i)->getSourceRange());
773 llvm::SmallVector<Expr*, 32> exprs;
775 for (unsigned i = 0, e = TheCall->getNumArgs(); i != e; i++) {
776 exprs.push_back(TheCall->getArg(i));
777 TheCall->setArg(i, 0);
780 return Owned(new (Context) ShuffleVectorExpr(Context, exprs.begin(),
781 exprs.size(), resType,
782 TheCall->getCallee()->getLocStart(),
783 TheCall->getRParenLoc()));
786 /// SemaBuiltinPrefetch - Handle __builtin_prefetch.
787 // This is declared to take (const void*, ...) and can take two
788 // optional constant int args.
789 bool Sema::SemaBuiltinPrefetch(CallExpr *TheCall) {
790 unsigned NumArgs = TheCall->getNumArgs();
793 return Diag(TheCall->getLocEnd(),
794 diag::err_typecheck_call_too_many_args_at_most)
795 << 0 /*function call*/ << 3 << NumArgs
796 << TheCall->getSourceRange();
798 // Argument 0 is checked for us and the remaining arguments must be
799 // constant integers.
800 for (unsigned i = 1; i != NumArgs; ++i) {
801 Expr *Arg = TheCall->getArg(i);
804 if (SemaBuiltinConstantArg(TheCall, i, Result))
807 // FIXME: gcc issues a warning and rewrites these to 0. These
808 // seems especially odd for the third argument since the default
811 if (Result.getLimitedValue() > 1)
812 return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range)
813 << "0" << "1" << Arg->getSourceRange();
815 if (Result.getLimitedValue() > 3)
816 return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range)
817 << "0" << "3" << Arg->getSourceRange();
824 /// SemaBuiltinConstantArg - Handle a check if argument ArgNum of CallExpr
825 /// TheCall is a constant expression.
826 bool Sema::SemaBuiltinConstantArg(CallExpr *TheCall, int ArgNum,
827 llvm::APSInt &Result) {
828 Expr *Arg = TheCall->getArg(ArgNum);
829 DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts());
830 FunctionDecl *FDecl = cast<FunctionDecl>(DRE->getDecl());
832 if (Arg->isTypeDependent() || Arg->isValueDependent()) return false;
834 if (!Arg->isIntegerConstantExpr(Result, Context))
835 return Diag(TheCall->getLocStart(), diag::err_constant_integer_arg_type)
836 << FDecl->getDeclName() << Arg->getSourceRange();
841 /// SemaBuiltinObjectSize - Handle __builtin_object_size(void *ptr,
842 /// int type). This simply type checks that type is one of the defined
844 // For compatability check 0-3, llvm only handles 0 and 2.
845 bool Sema::SemaBuiltinObjectSize(CallExpr *TheCall) {
848 // Check constant-ness first.
849 if (SemaBuiltinConstantArg(TheCall, 1, Result))
852 Expr *Arg = TheCall->getArg(1);
853 if (Result.getSExtValue() < 0 || Result.getSExtValue() > 3) {
854 return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range)
855 << "0" << "3" << SourceRange(Arg->getLocStart(), Arg->getLocEnd());
861 /// SemaBuiltinLongjmp - Handle __builtin_longjmp(void *env[5], int val).
862 /// This checks that val is a constant 1.
863 bool Sema::SemaBuiltinLongjmp(CallExpr *TheCall) {
864 Expr *Arg = TheCall->getArg(1);
867 // TODO: This is less than ideal. Overload this to take a value.
868 if (SemaBuiltinConstantArg(TheCall, 1, Result))
872 return Diag(TheCall->getLocStart(), diag::err_builtin_longjmp_invalid_val)
873 << SourceRange(Arg->getLocStart(), Arg->getLocEnd());
878 // Handle i > 1 ? "x" : "y", recursivelly
879 bool Sema::SemaCheckStringLiteral(const Expr *E, const CallExpr *TheCall,
881 unsigned format_idx, unsigned firstDataArg,
884 if (E->isTypeDependent() || E->isValueDependent())
887 switch (E->getStmtClass()) {
888 case Stmt::BinaryConditionalOperatorClass:
889 case Stmt::ConditionalOperatorClass: {
890 const AbstractConditionalOperator *C = cast<AbstractConditionalOperator>(E);
891 return SemaCheckStringLiteral(C->getTrueExpr(), TheCall, HasVAListArg,
892 format_idx, firstDataArg, isPrintf)
893 && SemaCheckStringLiteral(C->getFalseExpr(), TheCall, HasVAListArg,
894 format_idx, firstDataArg, isPrintf);
897 case Stmt::IntegerLiteralClass:
898 // Technically -Wformat-nonliteral does not warn about this case.
899 // The behavior of printf and friends in this case is implementation
900 // dependent. Ideally if the format string cannot be null then
901 // it should have a 'nonnull' attribute in the function prototype.
904 case Stmt::ImplicitCastExprClass: {
905 E = cast<ImplicitCastExpr>(E)->getSubExpr();
909 case Stmt::ParenExprClass: {
910 E = cast<ParenExpr>(E)->getSubExpr();
914 case Stmt::OpaqueValueExprClass:
915 if (const Expr *src = cast<OpaqueValueExpr>(E)->getSourceExpr()) {
921 case Stmt::DeclRefExprClass: {
922 const DeclRefExpr *DR = cast<DeclRefExpr>(E);
924 // As an exception, do not flag errors for variables binding to
925 // const string literals.
926 if (const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl())) {
927 bool isConstant = false;
928 QualType T = DR->getType();
930 if (const ArrayType *AT = Context.getAsArrayType(T)) {
931 isConstant = AT->getElementType().isConstant(Context);
932 } else if (const PointerType *PT = T->getAs<PointerType>()) {
933 isConstant = T.isConstant(Context) &&
934 PT->getPointeeType().isConstant(Context);
938 if (const Expr *Init = VD->getAnyInitializer())
939 return SemaCheckStringLiteral(Init, TheCall,
940 HasVAListArg, format_idx, firstDataArg,
944 // For vprintf* functions (i.e., HasVAListArg==true), we add a
945 // special check to see if the format string is a function parameter
946 // of the function calling the printf function. If the function
947 // has an attribute indicating it is a printf-like function, then we
948 // should suppress warnings concerning non-literals being used in a call
949 // to a vprintf function. For example:
952 // logmessage(char const *fmt __attribute__ (format (printf, 1, 2)), ...){
954 // va_start(ap, fmt);
955 // vprintf(fmt, ap); // Do NOT emit a warning about "fmt".
959 // FIXME: We don't have full attribute support yet, so just check to see
960 // if the argument is a DeclRefExpr that references a parameter. We'll
961 // add proper support for checking the attribute later.
963 if (isa<ParmVarDecl>(VD))
970 case Stmt::CallExprClass: {
971 const CallExpr *CE = cast<CallExpr>(E);
972 if (const ImplicitCastExpr *ICE
973 = dyn_cast<ImplicitCastExpr>(CE->getCallee())) {
974 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(ICE->getSubExpr())) {
975 if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(DRE->getDecl())) {
976 if (const FormatArgAttr *FA = FD->getAttr<FormatArgAttr>()) {
977 unsigned ArgIndex = FA->getFormatIdx();
978 const Expr *Arg = CE->getArg(ArgIndex - 1);
980 return SemaCheckStringLiteral(Arg, TheCall, HasVAListArg,
981 format_idx, firstDataArg, isPrintf);
989 case Stmt::ObjCStringLiteralClass:
990 case Stmt::StringLiteralClass: {
991 const StringLiteral *StrE = NULL;
993 if (const ObjCStringLiteral *ObjCFExpr = dyn_cast<ObjCStringLiteral>(E))
994 StrE = ObjCFExpr->getString();
996 StrE = cast<StringLiteral>(E);
999 CheckFormatString(StrE, E, TheCall, HasVAListArg, format_idx,
1000 firstDataArg, isPrintf);
1013 Sema::CheckNonNullArguments(const NonNullAttr *NonNull,
1014 const CallExpr *TheCall) {
1015 for (NonNullAttr::args_iterator i = NonNull->args_begin(),
1016 e = NonNull->args_end();
1018 const Expr *ArgExpr = TheCall->getArg(*i);
1019 if (ArgExpr->isNullPointerConstant(Context,
1020 Expr::NPC_ValueDependentIsNotNull))
1021 Diag(TheCall->getCallee()->getLocStart(), diag::warn_null_arg)
1022 << ArgExpr->getSourceRange();
1026 /// CheckPrintfScanfArguments - Check calls to printf and scanf (and similar
1027 /// functions) for correct use of format strings.
1029 Sema::CheckPrintfScanfArguments(const CallExpr *TheCall, bool HasVAListArg,
1030 unsigned format_idx, unsigned firstDataArg,
1033 const Expr *Fn = TheCall->getCallee();
1035 // The way the format attribute works in GCC, the implicit this argument
1036 // of member functions is counted. However, it doesn't appear in our own
1037 // lists, so decrement format_idx in that case.
1038 if (isa<CXXMemberCallExpr>(TheCall)) {
1039 const CXXMethodDecl *method_decl =
1040 dyn_cast<CXXMethodDecl>(TheCall->getCalleeDecl());
1041 if (method_decl && method_decl->isInstance()) {
1042 // Catch a format attribute mistakenly referring to the object argument.
1043 if (format_idx == 0)
1046 if(firstDataArg != 0)
1051 // CHECK: printf/scanf-like function is called with no format string.
1052 if (format_idx >= TheCall->getNumArgs()) {
1053 Diag(TheCall->getRParenLoc(), diag::warn_missing_format_string)
1054 << Fn->getSourceRange();
1058 const Expr *OrigFormatExpr = TheCall->getArg(format_idx)->IgnoreParenCasts();
1060 // CHECK: format string is not a string literal.
1062 // Dynamically generated format strings are difficult to
1063 // automatically vet at compile time. Requiring that format strings
1064 // are string literals: (1) permits the checking of format strings by
1065 // the compiler and thereby (2) can practically remove the source of
1066 // many format string exploits.
1068 // Format string can be either ObjC string (e.g. @"%d") or
1069 // C string (e.g. "%d")
1070 // ObjC string uses the same format specifiers as C string, so we can use
1071 // the same format string checking logic for both ObjC and C strings.
1072 if (SemaCheckStringLiteral(OrigFormatExpr, TheCall, HasVAListArg, format_idx,
1073 firstDataArg, isPrintf))
1074 return; // Literal format string found, check done!
1076 // If there are no arguments specified, warn with -Wformat-security, otherwise
1077 // warn only with -Wformat-nonliteral.
1078 if (TheCall->getNumArgs() == format_idx+1)
1079 Diag(TheCall->getArg(format_idx)->getLocStart(),
1080 diag::warn_format_nonliteral_noargs)
1081 << OrigFormatExpr->getSourceRange();
1083 Diag(TheCall->getArg(format_idx)->getLocStart(),
1084 diag::warn_format_nonliteral)
1085 << OrigFormatExpr->getSourceRange();
1089 class CheckFormatHandler : public analyze_format_string::FormatStringHandler {
1092 const StringLiteral *FExpr;
1093 const Expr *OrigFormatExpr;
1094 const unsigned FirstDataArg;
1095 const unsigned NumDataArgs;
1096 const bool IsObjCLiteral;
1097 const char *Beg; // Start of format string.
1098 const bool HasVAListArg;
1099 const CallExpr *TheCall;
1101 llvm::BitVector CoveredArgs;
1102 bool usesPositionalArgs;
1105 CheckFormatHandler(Sema &s, const StringLiteral *fexpr,
1106 const Expr *origFormatExpr, unsigned firstDataArg,
1107 unsigned numDataArgs, bool isObjCLiteral,
1108 const char *beg, bool hasVAListArg,
1109 const CallExpr *theCall, unsigned formatIdx)
1110 : S(s), FExpr(fexpr), OrigFormatExpr(origFormatExpr),
1111 FirstDataArg(firstDataArg),
1112 NumDataArgs(numDataArgs),
1113 IsObjCLiteral(isObjCLiteral), Beg(beg),
1114 HasVAListArg(hasVAListArg),
1115 TheCall(theCall), FormatIdx(formatIdx),
1116 usesPositionalArgs(false), atFirstArg(true) {
1117 CoveredArgs.resize(numDataArgs);
1118 CoveredArgs.reset();
1121 void DoneProcessing();
1123 void HandleIncompleteSpecifier(const char *startSpecifier,
1124 unsigned specifierLen);
1126 virtual void HandleInvalidPosition(const char *startSpecifier,
1127 unsigned specifierLen,
1128 analyze_format_string::PositionContext p);
1130 virtual void HandleZeroPosition(const char *startPos, unsigned posLen);
1132 void HandleNullChar(const char *nullCharacter);
1135 bool HandleInvalidConversionSpecifier(unsigned argIndex, SourceLocation Loc,
1136 const char *startSpec,
1137 unsigned specifierLen,
1138 const char *csStart, unsigned csLen);
1140 SourceRange getFormatStringRange();
1141 CharSourceRange getSpecifierRange(const char *startSpecifier,
1142 unsigned specifierLen);
1143 SourceLocation getLocationOfByte(const char *x);
1145 const Expr *getDataArg(unsigned i) const;
1147 bool CheckNumArgs(const analyze_format_string::FormatSpecifier &FS,
1148 const analyze_format_string::ConversionSpecifier &CS,
1149 const char *startSpecifier, unsigned specifierLen,
1154 SourceRange CheckFormatHandler::getFormatStringRange() {
1155 return OrigFormatExpr->getSourceRange();
1158 CharSourceRange CheckFormatHandler::
1159 getSpecifierRange(const char *startSpecifier, unsigned specifierLen) {
1160 SourceLocation Start = getLocationOfByte(startSpecifier);
1161 SourceLocation End = getLocationOfByte(startSpecifier + specifierLen - 1);
1163 // Advance the end SourceLocation by one due to half-open ranges.
1164 End = End.getFileLocWithOffset(1);
1166 return CharSourceRange::getCharRange(Start, End);
1169 SourceLocation CheckFormatHandler::getLocationOfByte(const char *x) {
1170 return S.getLocationOfStringLiteralByte(FExpr, x - Beg);
1173 void CheckFormatHandler::HandleIncompleteSpecifier(const char *startSpecifier,
1174 unsigned specifierLen){
1175 SourceLocation Loc = getLocationOfByte(startSpecifier);
1176 S.Diag(Loc, diag::warn_printf_incomplete_specifier)
1177 << getSpecifierRange(startSpecifier, specifierLen);
1181 CheckFormatHandler::HandleInvalidPosition(const char *startPos, unsigned posLen,
1182 analyze_format_string::PositionContext p) {
1183 SourceLocation Loc = getLocationOfByte(startPos);
1184 S.Diag(Loc, diag::warn_format_invalid_positional_specifier)
1185 << (unsigned) p << getSpecifierRange(startPos, posLen);
1188 void CheckFormatHandler::HandleZeroPosition(const char *startPos,
1190 SourceLocation Loc = getLocationOfByte(startPos);
1191 S.Diag(Loc, diag::warn_format_zero_positional_specifier)
1192 << getSpecifierRange(startPos, posLen);
1195 void CheckFormatHandler::HandleNullChar(const char *nullCharacter) {
1196 // The presence of a null character is likely an error.
1197 S.Diag(getLocationOfByte(nullCharacter),
1198 diag::warn_printf_format_string_contains_null_char)
1199 << getFormatStringRange();
1202 const Expr *CheckFormatHandler::getDataArg(unsigned i) const {
1203 return TheCall->getArg(FirstDataArg + i);
1206 void CheckFormatHandler::DoneProcessing() {
1207 // Does the number of data arguments exceed the number of
1208 // format conversions in the format string?
1209 if (!HasVAListArg) {
1210 // Find any arguments that weren't covered.
1212 signed notCoveredArg = CoveredArgs.find_first();
1213 if (notCoveredArg >= 0) {
1214 assert((unsigned)notCoveredArg < NumDataArgs);
1215 S.Diag(getDataArg((unsigned) notCoveredArg)->getLocStart(),
1216 diag::warn_printf_data_arg_not_used)
1217 << getFormatStringRange();
1223 CheckFormatHandler::HandleInvalidConversionSpecifier(unsigned argIndex,
1225 const char *startSpec,
1226 unsigned specifierLen,
1227 const char *csStart,
1230 bool keepGoing = true;
1231 if (argIndex < NumDataArgs) {
1232 // Consider the argument coverered, even though the specifier doesn't
1234 CoveredArgs.set(argIndex);
1237 // If argIndex exceeds the number of data arguments we
1238 // don't issue a warning because that is just a cascade of warnings (and
1239 // they may have intended '%%' anyway). We don't want to continue processing
1240 // the format string after this point, however, as we will like just get
1241 // gibberish when trying to match arguments.
1245 S.Diag(Loc, diag::warn_format_invalid_conversion)
1246 << llvm::StringRef(csStart, csLen)
1247 << getSpecifierRange(startSpec, specifierLen);
1253 CheckFormatHandler::CheckNumArgs(
1254 const analyze_format_string::FormatSpecifier &FS,
1255 const analyze_format_string::ConversionSpecifier &CS,
1256 const char *startSpecifier, unsigned specifierLen, unsigned argIndex) {
1258 if (argIndex >= NumDataArgs) {
1259 if (FS.usesPositionalArg()) {
1260 S.Diag(getLocationOfByte(CS.getStart()),
1261 diag::warn_printf_positional_arg_exceeds_data_args)
1262 << (argIndex+1) << NumDataArgs
1263 << getSpecifierRange(startSpecifier, specifierLen);
1266 S.Diag(getLocationOfByte(CS.getStart()),
1267 diag::warn_printf_insufficient_data_args)
1268 << getSpecifierRange(startSpecifier, specifierLen);
1276 //===--- CHECK: Printf format string checking ------------------------------===//
1279 class CheckPrintfHandler : public CheckFormatHandler {
1281 CheckPrintfHandler(Sema &s, const StringLiteral *fexpr,
1282 const Expr *origFormatExpr, unsigned firstDataArg,
1283 unsigned numDataArgs, bool isObjCLiteral,
1284 const char *beg, bool hasVAListArg,
1285 const CallExpr *theCall, unsigned formatIdx)
1286 : CheckFormatHandler(s, fexpr, origFormatExpr, firstDataArg,
1287 numDataArgs, isObjCLiteral, beg, hasVAListArg,
1288 theCall, formatIdx) {}
1291 bool HandleInvalidPrintfConversionSpecifier(
1292 const analyze_printf::PrintfSpecifier &FS,
1293 const char *startSpecifier,
1294 unsigned specifierLen);
1296 bool HandlePrintfSpecifier(const analyze_printf::PrintfSpecifier &FS,
1297 const char *startSpecifier,
1298 unsigned specifierLen);
1300 bool HandleAmount(const analyze_format_string::OptionalAmount &Amt, unsigned k,
1301 const char *startSpecifier, unsigned specifierLen);
1302 void HandleInvalidAmount(const analyze_printf::PrintfSpecifier &FS,
1303 const analyze_printf::OptionalAmount &Amt,
1305 const char *startSpecifier, unsigned specifierLen);
1306 void HandleFlag(const analyze_printf::PrintfSpecifier &FS,
1307 const analyze_printf::OptionalFlag &flag,
1308 const char *startSpecifier, unsigned specifierLen);
1309 void HandleIgnoredFlag(const analyze_printf::PrintfSpecifier &FS,
1310 const analyze_printf::OptionalFlag &ignoredFlag,
1311 const analyze_printf::OptionalFlag &flag,
1312 const char *startSpecifier, unsigned specifierLen);
1316 bool CheckPrintfHandler::HandleInvalidPrintfConversionSpecifier(
1317 const analyze_printf::PrintfSpecifier &FS,
1318 const char *startSpecifier,
1319 unsigned specifierLen) {
1320 const analyze_printf::PrintfConversionSpecifier &CS =
1321 FS.getConversionSpecifier();
1323 return HandleInvalidConversionSpecifier(FS.getArgIndex(),
1324 getLocationOfByte(CS.getStart()),
1325 startSpecifier, specifierLen,
1326 CS.getStart(), CS.getLength());
1329 bool CheckPrintfHandler::HandleAmount(
1330 const analyze_format_string::OptionalAmount &Amt,
1331 unsigned k, const char *startSpecifier,
1332 unsigned specifierLen) {
1334 if (Amt.hasDataArgument()) {
1335 if (!HasVAListArg) {
1336 unsigned argIndex = Amt.getArgIndex();
1337 if (argIndex >= NumDataArgs) {
1338 S.Diag(getLocationOfByte(Amt.getStart()),
1339 diag::warn_printf_asterisk_missing_arg)
1340 << k << getSpecifierRange(startSpecifier, specifierLen);
1341 // Don't do any more checking. We will just emit
1346 // Type check the data argument. It should be an 'int'.
1347 // Although not in conformance with C99, we also allow the argument to be
1348 // an 'unsigned int' as that is a reasonably safe case. GCC also
1349 // doesn't emit a warning for that case.
1350 CoveredArgs.set(argIndex);
1351 const Expr *Arg = getDataArg(argIndex);
1352 QualType T = Arg->getType();
1354 const analyze_printf::ArgTypeResult &ATR = Amt.getArgType(S.Context);
1355 assert(ATR.isValid());
1357 if (!ATR.matchesType(S.Context, T)) {
1358 S.Diag(getLocationOfByte(Amt.getStart()),
1359 diag::warn_printf_asterisk_wrong_type)
1361 << ATR.getRepresentativeType(S.Context) << T
1362 << getSpecifierRange(startSpecifier, specifierLen)
1363 << Arg->getSourceRange();
1364 // Don't do any more checking. We will just emit
1373 void CheckPrintfHandler::HandleInvalidAmount(
1374 const analyze_printf::PrintfSpecifier &FS,
1375 const analyze_printf::OptionalAmount &Amt,
1377 const char *startSpecifier,
1378 unsigned specifierLen) {
1379 const analyze_printf::PrintfConversionSpecifier &CS =
1380 FS.getConversionSpecifier();
1381 switch (Amt.getHowSpecified()) {
1382 case analyze_printf::OptionalAmount::Constant:
1383 S.Diag(getLocationOfByte(Amt.getStart()),
1384 diag::warn_printf_nonsensical_optional_amount)
1387 << getSpecifierRange(startSpecifier, specifierLen)
1388 << FixItHint::CreateRemoval(getSpecifierRange(Amt.getStart(),
1389 Amt.getConstantLength()));
1393 S.Diag(getLocationOfByte(Amt.getStart()),
1394 diag::warn_printf_nonsensical_optional_amount)
1397 << getSpecifierRange(startSpecifier, specifierLen);
1402 void CheckPrintfHandler::HandleFlag(const analyze_printf::PrintfSpecifier &FS,
1403 const analyze_printf::OptionalFlag &flag,
1404 const char *startSpecifier,
1405 unsigned specifierLen) {
1406 // Warn about pointless flag with a fixit removal.
1407 const analyze_printf::PrintfConversionSpecifier &CS =
1408 FS.getConversionSpecifier();
1409 S.Diag(getLocationOfByte(flag.getPosition()),
1410 diag::warn_printf_nonsensical_flag)
1411 << flag.toString() << CS.toString()
1412 << getSpecifierRange(startSpecifier, specifierLen)
1413 << FixItHint::CreateRemoval(getSpecifierRange(flag.getPosition(), 1));
1416 void CheckPrintfHandler::HandleIgnoredFlag(
1417 const analyze_printf::PrintfSpecifier &FS,
1418 const analyze_printf::OptionalFlag &ignoredFlag,
1419 const analyze_printf::OptionalFlag &flag,
1420 const char *startSpecifier,
1421 unsigned specifierLen) {
1422 // Warn about ignored flag with a fixit removal.
1423 S.Diag(getLocationOfByte(ignoredFlag.getPosition()),
1424 diag::warn_printf_ignored_flag)
1425 << ignoredFlag.toString() << flag.toString()
1426 << getSpecifierRange(startSpecifier, specifierLen)
1427 << FixItHint::CreateRemoval(getSpecifierRange(
1428 ignoredFlag.getPosition(), 1));
1432 CheckPrintfHandler::HandlePrintfSpecifier(const analyze_printf::PrintfSpecifier
1434 const char *startSpecifier,
1435 unsigned specifierLen) {
1437 using namespace analyze_format_string;
1438 using namespace analyze_printf;
1439 const PrintfConversionSpecifier &CS = FS.getConversionSpecifier();
1441 if (FS.consumesDataArgument()) {
1444 usesPositionalArgs = FS.usesPositionalArg();
1446 else if (usesPositionalArgs != FS.usesPositionalArg()) {
1447 // Cannot mix-and-match positional and non-positional arguments.
1448 S.Diag(getLocationOfByte(CS.getStart()),
1449 diag::warn_format_mix_positional_nonpositional_args)
1450 << getSpecifierRange(startSpecifier, specifierLen);
1455 // First check if the field width, precision, and conversion specifier
1456 // have matching data arguments.
1457 if (!HandleAmount(FS.getFieldWidth(), /* field width */ 0,
1458 startSpecifier, specifierLen)) {
1462 if (!HandleAmount(FS.getPrecision(), /* precision */ 1,
1463 startSpecifier, specifierLen)) {
1467 if (!CS.consumesDataArgument()) {
1468 // FIXME: Technically specifying a precision or field width here
1469 // makes no sense. Worth issuing a warning at some point.
1473 // Consume the argument.
1474 unsigned argIndex = FS.getArgIndex();
1475 if (argIndex < NumDataArgs) {
1476 // The check to see if the argIndex is valid will come later.
1477 // We set the bit here because we may exit early from this
1478 // function if we encounter some other error.
1479 CoveredArgs.set(argIndex);
1482 // Check for using an Objective-C specific conversion specifier
1483 // in a non-ObjC literal.
1484 if (!IsObjCLiteral && CS.isObjCArg()) {
1485 return HandleInvalidPrintfConversionSpecifier(FS, startSpecifier,
1489 // Check for invalid use of field width
1490 if (!FS.hasValidFieldWidth()) {
1491 HandleInvalidAmount(FS, FS.getFieldWidth(), /* field width */ 0,
1492 startSpecifier, specifierLen);
1495 // Check for invalid use of precision
1496 if (!FS.hasValidPrecision()) {
1497 HandleInvalidAmount(FS, FS.getPrecision(), /* precision */ 1,
1498 startSpecifier, specifierLen);
1501 // Check each flag does not conflict with any other component.
1502 if (!FS.hasValidThousandsGroupingPrefix())
1503 HandleFlag(FS, FS.hasThousandsGrouping(), startSpecifier, specifierLen);
1504 if (!FS.hasValidLeadingZeros())
1505 HandleFlag(FS, FS.hasLeadingZeros(), startSpecifier, specifierLen);
1506 if (!FS.hasValidPlusPrefix())
1507 HandleFlag(FS, FS.hasPlusPrefix(), startSpecifier, specifierLen);
1508 if (!FS.hasValidSpacePrefix())
1509 HandleFlag(FS, FS.hasSpacePrefix(), startSpecifier, specifierLen);
1510 if (!FS.hasValidAlternativeForm())
1511 HandleFlag(FS, FS.hasAlternativeForm(), startSpecifier, specifierLen);
1512 if (!FS.hasValidLeftJustified())
1513 HandleFlag(FS, FS.isLeftJustified(), startSpecifier, specifierLen);
1515 // Check that flags are not ignored by another flag
1516 if (FS.hasSpacePrefix() && FS.hasPlusPrefix()) // ' ' ignored by '+'
1517 HandleIgnoredFlag(FS, FS.hasSpacePrefix(), FS.hasPlusPrefix(),
1518 startSpecifier, specifierLen);
1519 if (FS.hasLeadingZeros() && FS.isLeftJustified()) // '0' ignored by '-'
1520 HandleIgnoredFlag(FS, FS.hasLeadingZeros(), FS.isLeftJustified(),
1521 startSpecifier, specifierLen);
1523 // Check the length modifier is valid with the given conversion specifier.
1524 const LengthModifier &LM = FS.getLengthModifier();
1525 if (!FS.hasValidLengthModifier())
1526 S.Diag(getLocationOfByte(LM.getStart()),
1527 diag::warn_format_nonsensical_length)
1528 << LM.toString() << CS.toString()
1529 << getSpecifierRange(startSpecifier, specifierLen)
1530 << FixItHint::CreateRemoval(getSpecifierRange(LM.getStart(),
1533 // Are we using '%n'?
1534 if (CS.getKind() == ConversionSpecifier::nArg) {
1535 // Issue a warning about this being a possible security issue.
1536 S.Diag(getLocationOfByte(CS.getStart()), diag::warn_printf_write_back)
1537 << getSpecifierRange(startSpecifier, specifierLen);
1538 // Continue checking the other format specifiers.
1542 // The remaining checks depend on the data arguments.
1546 if (!CheckNumArgs(FS, CS, startSpecifier, specifierLen, argIndex))
1549 // Now type check the data expression that matches the
1550 // format specifier.
1551 const Expr *Ex = getDataArg(argIndex);
1552 const analyze_printf::ArgTypeResult &ATR = FS.getArgType(S.Context);
1553 if (ATR.isValid() && !ATR.matchesType(S.Context, Ex->getType())) {
1554 // Check if we didn't match because of an implicit cast from a 'char'
1555 // or 'short' to an 'int'. This is done because printf is a varargs
1557 if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(Ex))
1558 if (ICE->getType() == S.Context.IntTy) {
1559 // All further checking is done on the subexpression.
1560 Ex = ICE->getSubExpr();
1561 if (ATR.matchesType(S.Context, Ex->getType()))
1565 // We may be able to offer a FixItHint if it is a supported type.
1566 PrintfSpecifier fixedFS = FS;
1567 bool success = fixedFS.fixType(Ex->getType());
1570 // Get the fix string from the fixed format specifier
1571 llvm::SmallString<128> buf;
1572 llvm::raw_svector_ostream os(buf);
1573 fixedFS.toString(os);
1575 // FIXME: getRepresentativeType() perhaps should return a string
1576 // instead of a QualType to better handle when the representative
1577 // type is 'wint_t' (which is defined in the system headers).
1578 S.Diag(getLocationOfByte(CS.getStart()),
1579 diag::warn_printf_conversion_argument_type_mismatch)
1580 << ATR.getRepresentativeType(S.Context) << Ex->getType()
1581 << getSpecifierRange(startSpecifier, specifierLen)
1582 << Ex->getSourceRange()
1583 << FixItHint::CreateReplacement(
1584 getSpecifierRange(startSpecifier, specifierLen),
1588 S.Diag(getLocationOfByte(CS.getStart()),
1589 diag::warn_printf_conversion_argument_type_mismatch)
1590 << ATR.getRepresentativeType(S.Context) << Ex->getType()
1591 << getSpecifierRange(startSpecifier, specifierLen)
1592 << Ex->getSourceRange();
1599 //===--- CHECK: Scanf format string checking ------------------------------===//
1602 class CheckScanfHandler : public CheckFormatHandler {
1604 CheckScanfHandler(Sema &s, const StringLiteral *fexpr,
1605 const Expr *origFormatExpr, unsigned firstDataArg,
1606 unsigned numDataArgs, bool isObjCLiteral,
1607 const char *beg, bool hasVAListArg,
1608 const CallExpr *theCall, unsigned formatIdx)
1609 : CheckFormatHandler(s, fexpr, origFormatExpr, firstDataArg,
1610 numDataArgs, isObjCLiteral, beg, hasVAListArg,
1611 theCall, formatIdx) {}
1613 bool HandleScanfSpecifier(const analyze_scanf::ScanfSpecifier &FS,
1614 const char *startSpecifier,
1615 unsigned specifierLen);
1617 bool HandleInvalidScanfConversionSpecifier(
1618 const analyze_scanf::ScanfSpecifier &FS,
1619 const char *startSpecifier,
1620 unsigned specifierLen);
1622 void HandleIncompleteScanList(const char *start, const char *end);
1626 void CheckScanfHandler::HandleIncompleteScanList(const char *start,
1628 S.Diag(getLocationOfByte(end), diag::warn_scanf_scanlist_incomplete)
1629 << getSpecifierRange(start, end - start);
1632 bool CheckScanfHandler::HandleInvalidScanfConversionSpecifier(
1633 const analyze_scanf::ScanfSpecifier &FS,
1634 const char *startSpecifier,
1635 unsigned specifierLen) {
1637 const analyze_scanf::ScanfConversionSpecifier &CS =
1638 FS.getConversionSpecifier();
1640 return HandleInvalidConversionSpecifier(FS.getArgIndex(),
1641 getLocationOfByte(CS.getStart()),
1642 startSpecifier, specifierLen,
1643 CS.getStart(), CS.getLength());
1646 bool CheckScanfHandler::HandleScanfSpecifier(
1647 const analyze_scanf::ScanfSpecifier &FS,
1648 const char *startSpecifier,
1649 unsigned specifierLen) {
1651 using namespace analyze_scanf;
1652 using namespace analyze_format_string;
1654 const ScanfConversionSpecifier &CS = FS.getConversionSpecifier();
1656 // Handle case where '%' and '*' don't consume an argument. These shouldn't
1657 // be used to decide if we are using positional arguments consistently.
1658 if (FS.consumesDataArgument()) {
1661 usesPositionalArgs = FS.usesPositionalArg();
1663 else if (usesPositionalArgs != FS.usesPositionalArg()) {
1664 // Cannot mix-and-match positional and non-positional arguments.
1665 S.Diag(getLocationOfByte(CS.getStart()),
1666 diag::warn_format_mix_positional_nonpositional_args)
1667 << getSpecifierRange(startSpecifier, specifierLen);
1672 // Check if the field with is non-zero.
1673 const OptionalAmount &Amt = FS.getFieldWidth();
1674 if (Amt.getHowSpecified() == OptionalAmount::Constant) {
1675 if (Amt.getConstantAmount() == 0) {
1676 const CharSourceRange &R = getSpecifierRange(Amt.getStart(),
1677 Amt.getConstantLength());
1678 S.Diag(getLocationOfByte(Amt.getStart()),
1679 diag::warn_scanf_nonzero_width)
1680 << R << FixItHint::CreateRemoval(R);
1684 if (!FS.consumesDataArgument()) {
1685 // FIXME: Technically specifying a precision or field width here
1686 // makes no sense. Worth issuing a warning at some point.
1690 // Consume the argument.
1691 unsigned argIndex = FS.getArgIndex();
1692 if (argIndex < NumDataArgs) {
1693 // The check to see if the argIndex is valid will come later.
1694 // We set the bit here because we may exit early from this
1695 // function if we encounter some other error.
1696 CoveredArgs.set(argIndex);
1699 // Check the length modifier is valid with the given conversion specifier.
1700 const LengthModifier &LM = FS.getLengthModifier();
1701 if (!FS.hasValidLengthModifier()) {
1702 S.Diag(getLocationOfByte(LM.getStart()),
1703 diag::warn_format_nonsensical_length)
1704 << LM.toString() << CS.toString()
1705 << getSpecifierRange(startSpecifier, specifierLen)
1706 << FixItHint::CreateRemoval(getSpecifierRange(LM.getStart(),
1710 // The remaining checks depend on the data arguments.
1714 if (!CheckNumArgs(FS, CS, startSpecifier, specifierLen, argIndex))
1717 // FIXME: Check that the argument type matches the format specifier.
1722 void Sema::CheckFormatString(const StringLiteral *FExpr,
1723 const Expr *OrigFormatExpr,
1724 const CallExpr *TheCall, bool HasVAListArg,
1725 unsigned format_idx, unsigned firstDataArg,
1728 // CHECK: is the format string a wide literal?
1729 if (FExpr->isWide()) {
1730 Diag(FExpr->getLocStart(),
1731 diag::warn_format_string_is_wide_literal)
1732 << OrigFormatExpr->getSourceRange();
1736 // Str - The format string. NOTE: this is NOT null-terminated!
1737 llvm::StringRef StrRef = FExpr->getString();
1738 const char *Str = StrRef.data();
1739 unsigned StrLen = StrRef.size();
1741 // CHECK: empty format string?
1743 Diag(FExpr->getLocStart(), diag::warn_empty_format_string)
1744 << OrigFormatExpr->getSourceRange();
1749 CheckPrintfHandler H(*this, FExpr, OrigFormatExpr, firstDataArg,
1750 TheCall->getNumArgs() - firstDataArg,
1751 isa<ObjCStringLiteral>(OrigFormatExpr), Str,
1752 HasVAListArg, TheCall, format_idx);
1754 if (!analyze_format_string::ParsePrintfString(H, Str, Str + StrLen))
1758 CheckScanfHandler H(*this, FExpr, OrigFormatExpr, firstDataArg,
1759 TheCall->getNumArgs() - firstDataArg,
1760 isa<ObjCStringLiteral>(OrigFormatExpr), Str,
1761 HasVAListArg, TheCall, format_idx);
1763 if (!analyze_format_string::ParseScanfString(H, Str, Str + StrLen))
1768 //===--- CHECK: Return Address of Stack Variable --------------------------===//
1770 static Expr *EvalVal(Expr *E, llvm::SmallVectorImpl<DeclRefExpr *> &refVars);
1771 static Expr *EvalAddr(Expr* E, llvm::SmallVectorImpl<DeclRefExpr *> &refVars);
1773 /// CheckReturnStackAddr - Check if a return statement returns the address
1774 /// of a stack variable.
1776 Sema::CheckReturnStackAddr(Expr *RetValExp, QualType lhsType,
1777 SourceLocation ReturnLoc) {
1780 llvm::SmallVector<DeclRefExpr *, 8> refVars;
1782 // Perform checking for returned stack addresses, local blocks,
1783 // label addresses or references to temporaries.
1784 if (lhsType->isPointerType() || lhsType->isBlockPointerType()) {
1785 stackE = EvalAddr(RetValExp, refVars);
1786 } else if (lhsType->isReferenceType()) {
1787 stackE = EvalVal(RetValExp, refVars);
1791 return; // Nothing suspicious was found.
1793 SourceLocation diagLoc;
1794 SourceRange diagRange;
1795 if (refVars.empty()) {
1796 diagLoc = stackE->getLocStart();
1797 diagRange = stackE->getSourceRange();
1799 // We followed through a reference variable. 'stackE' contains the
1800 // problematic expression but we will warn at the return statement pointing
1801 // at the reference variable. We will later display the "trail" of
1802 // reference variables using notes.
1803 diagLoc = refVars[0]->getLocStart();
1804 diagRange = refVars[0]->getSourceRange();
1807 if (DeclRefExpr *DR = dyn_cast<DeclRefExpr>(stackE)) { //address of local var.
1808 Diag(diagLoc, lhsType->isReferenceType() ? diag::warn_ret_stack_ref
1809 : diag::warn_ret_stack_addr)
1810 << DR->getDecl()->getDeclName() << diagRange;
1811 } else if (isa<BlockExpr>(stackE)) { // local block.
1812 Diag(diagLoc, diag::err_ret_local_block) << diagRange;
1813 } else if (isa<AddrLabelExpr>(stackE)) { // address of label.
1814 Diag(diagLoc, diag::warn_ret_addr_label) << diagRange;
1815 } else { // local temporary.
1816 Diag(diagLoc, lhsType->isReferenceType() ? diag::warn_ret_local_temp_ref
1817 : diag::warn_ret_local_temp_addr)
1821 // Display the "trail" of reference variables that we followed until we
1822 // found the problematic expression using notes.
1823 for (unsigned i = 0, e = refVars.size(); i != e; ++i) {
1824 VarDecl *VD = cast<VarDecl>(refVars[i]->getDecl());
1825 // If this var binds to another reference var, show the range of the next
1826 // var, otherwise the var binds to the problematic expression, in which case
1827 // show the range of the expression.
1828 SourceRange range = (i < e-1) ? refVars[i+1]->getSourceRange()
1829 : stackE->getSourceRange();
1830 Diag(VD->getLocation(), diag::note_ref_var_local_bind)
1831 << VD->getDeclName() << range;
1835 /// EvalAddr - EvalAddr and EvalVal are mutually recursive functions that
1836 /// check if the expression in a return statement evaluates to an address
1837 /// to a location on the stack, a local block, an address of a label, or a
1838 /// reference to local temporary. The recursion is used to traverse the
1839 /// AST of the return expression, with recursion backtracking when we
1840 /// encounter a subexpression that (1) clearly does not lead to one of the
1841 /// above problematic expressions (2) is something we cannot determine leads to
1842 /// a problematic expression based on such local checking.
1844 /// Both EvalAddr and EvalVal follow through reference variables to evaluate
1845 /// the expression that they point to. Such variables are added to the
1846 /// 'refVars' vector so that we know what the reference variable "trail" was.
1848 /// EvalAddr processes expressions that are pointers that are used as
1849 /// references (and not L-values). EvalVal handles all other values.
1850 /// At the base case of the recursion is a check for the above problematic
1853 /// This implementation handles:
1855 /// * pointer-to-pointer casts
1856 /// * implicit conversions from array references to pointers
1857 /// * taking the address of fields
1858 /// * arbitrary interplay between "&" and "*" operators
1859 /// * pointer arithmetic from an address of a stack variable
1860 /// * taking the address of an array element where the array is on the stack
1861 static Expr *EvalAddr(Expr *E, llvm::SmallVectorImpl<DeclRefExpr *> &refVars) {
1862 if (E->isTypeDependent())
1865 // We should only be called for evaluating pointer expressions.
1866 assert((E->getType()->isAnyPointerType() ||
1867 E->getType()->isBlockPointerType() ||
1868 E->getType()->isObjCQualifiedIdType()) &&
1869 "EvalAddr only works on pointers");
1871 // Our "symbolic interpreter" is just a dispatch off the currently
1872 // viewed AST node. We then recursively traverse the AST by calling
1873 // EvalAddr and EvalVal appropriately.
1874 switch (E->getStmtClass()) {
1875 case Stmt::ParenExprClass:
1876 // Ignore parentheses.
1877 return EvalAddr(cast<ParenExpr>(E)->getSubExpr(), refVars);
1879 case Stmt::DeclRefExprClass: {
1880 DeclRefExpr *DR = cast<DeclRefExpr>(E);
1882 if (VarDecl *V = dyn_cast<VarDecl>(DR->getDecl()))
1883 // If this is a reference variable, follow through to the expression that
1885 if (V->hasLocalStorage() &&
1886 V->getType()->isReferenceType() && V->hasInit()) {
1887 // Add the reference variable to the "trail".
1888 refVars.push_back(DR);
1889 return EvalAddr(V->getInit(), refVars);
1895 case Stmt::UnaryOperatorClass: {
1896 // The only unary operator that make sense to handle here
1897 // is AddrOf. All others don't make sense as pointers.
1898 UnaryOperator *U = cast<UnaryOperator>(E);
1900 if (U->getOpcode() == UO_AddrOf)
1901 return EvalVal(U->getSubExpr(), refVars);
1906 case Stmt::BinaryOperatorClass: {
1907 // Handle pointer arithmetic. All other binary operators are not valid
1909 BinaryOperator *B = cast<BinaryOperator>(E);
1910 BinaryOperatorKind op = B->getOpcode();
1912 if (op != BO_Add && op != BO_Sub)
1915 Expr *Base = B->getLHS();
1917 // Determine which argument is the real pointer base. It could be
1918 // the RHS argument instead of the LHS.
1919 if (!Base->getType()->isPointerType()) Base = B->getRHS();
1921 assert (Base->getType()->isPointerType());
1922 return EvalAddr(Base, refVars);
1925 // For conditional operators we need to see if either the LHS or RHS are
1926 // valid DeclRefExpr*s. If one of them is valid, we return it.
1927 case Stmt::ConditionalOperatorClass: {
1928 ConditionalOperator *C = cast<ConditionalOperator>(E);
1930 // Handle the GNU extension for missing LHS.
1931 if (Expr *lhsExpr = C->getLHS()) {
1932 // In C++, we can have a throw-expression, which has 'void' type.
1933 if (!lhsExpr->getType()->isVoidType())
1934 if (Expr* LHS = EvalAddr(lhsExpr, refVars))
1938 // In C++, we can have a throw-expression, which has 'void' type.
1939 if (C->getRHS()->getType()->isVoidType())
1942 return EvalAddr(C->getRHS(), refVars);
1945 case Stmt::BlockExprClass:
1946 if (cast<BlockExpr>(E)->getBlockDecl()->hasCaptures())
1947 return E; // local block.
1950 case Stmt::AddrLabelExprClass:
1951 return E; // address of label.
1953 // For casts, we need to handle conversions from arrays to
1954 // pointer values, and pointer-to-pointer conversions.
1955 case Stmt::ImplicitCastExprClass:
1956 case Stmt::CStyleCastExprClass:
1957 case Stmt::CXXFunctionalCastExprClass: {
1958 Expr* SubExpr = cast<CastExpr>(E)->getSubExpr();
1959 QualType T = SubExpr->getType();
1961 if (SubExpr->getType()->isPointerType() ||
1962 SubExpr->getType()->isBlockPointerType() ||
1963 SubExpr->getType()->isObjCQualifiedIdType())
1964 return EvalAddr(SubExpr, refVars);
1965 else if (T->isArrayType())
1966 return EvalVal(SubExpr, refVars);
1971 // C++ casts. For dynamic casts, static casts, and const casts, we
1972 // are always converting from a pointer-to-pointer, so we just blow
1973 // through the cast. In the case the dynamic cast doesn't fail (and
1974 // return NULL), we take the conservative route and report cases
1975 // where we return the address of a stack variable. For Reinterpre
1976 // FIXME: The comment about is wrong; we're not always converting
1977 // from pointer to pointer. I'm guessing that this code should also
1978 // handle references to objects.
1979 case Stmt::CXXStaticCastExprClass:
1980 case Stmt::CXXDynamicCastExprClass:
1981 case Stmt::CXXConstCastExprClass:
1982 case Stmt::CXXReinterpretCastExprClass: {
1983 Expr *S = cast<CXXNamedCastExpr>(E)->getSubExpr();
1984 if (S->getType()->isPointerType() || S->getType()->isBlockPointerType())
1985 return EvalAddr(S, refVars);
1990 // Everything else: we simply don't reason about them.
1997 /// EvalVal - This function is complements EvalAddr in the mutual recursion.
1998 /// See the comments for EvalAddr for more details.
1999 static Expr *EvalVal(Expr *E, llvm::SmallVectorImpl<DeclRefExpr *> &refVars) {
2001 // We should only be called for evaluating non-pointer expressions, or
2002 // expressions with a pointer type that are not used as references but instead
2003 // are l-values (e.g., DeclRefExpr with a pointer type).
2005 // Our "symbolic interpreter" is just a dispatch off the currently
2006 // viewed AST node. We then recursively traverse the AST by calling
2007 // EvalAddr and EvalVal appropriately.
2008 switch (E->getStmtClass()) {
2009 case Stmt::ImplicitCastExprClass: {
2010 ImplicitCastExpr *IE = cast<ImplicitCastExpr>(E);
2011 if (IE->getValueKind() == VK_LValue) {
2012 E = IE->getSubExpr();
2018 case Stmt::DeclRefExprClass: {
2019 // When we hit a DeclRefExpr we are looking at code that refers to a
2020 // variable's name. If it's not a reference variable we check if it has
2021 // local storage within the function, and if so, return the expression.
2022 DeclRefExpr *DR = cast<DeclRefExpr>(E);
2024 if (VarDecl *V = dyn_cast<VarDecl>(DR->getDecl()))
2025 if (V->hasLocalStorage()) {
2026 if (!V->getType()->isReferenceType())
2029 // Reference variable, follow through to the expression that
2032 // Add the reference variable to the "trail".
2033 refVars.push_back(DR);
2034 return EvalVal(V->getInit(), refVars);
2041 case Stmt::ParenExprClass: {
2042 // Ignore parentheses.
2043 E = cast<ParenExpr>(E)->getSubExpr();
2047 case Stmt::UnaryOperatorClass: {
2048 // The only unary operator that make sense to handle here
2049 // is Deref. All others don't resolve to a "name." This includes
2050 // handling all sorts of rvalues passed to a unary operator.
2051 UnaryOperator *U = cast<UnaryOperator>(E);
2053 if (U->getOpcode() == UO_Deref)
2054 return EvalAddr(U->getSubExpr(), refVars);
2059 case Stmt::ArraySubscriptExprClass: {
2060 // Array subscripts are potential references to data on the stack. We
2061 // retrieve the DeclRefExpr* for the array variable if it indeed
2062 // has local storage.
2063 return EvalAddr(cast<ArraySubscriptExpr>(E)->getBase(), refVars);
2066 case Stmt::ConditionalOperatorClass: {
2067 // For conditional operators we need to see if either the LHS or RHS are
2068 // non-NULL Expr's. If one is non-NULL, we return it.
2069 ConditionalOperator *C = cast<ConditionalOperator>(E);
2071 // Handle the GNU extension for missing LHS.
2072 if (Expr *lhsExpr = C->getLHS())
2073 if (Expr *LHS = EvalVal(lhsExpr, refVars))
2076 return EvalVal(C->getRHS(), refVars);
2079 // Accesses to members are potential references to data on the stack.
2080 case Stmt::MemberExprClass: {
2081 MemberExpr *M = cast<MemberExpr>(E);
2083 // Check for indirect access. We only want direct field accesses.
2087 // Check whether the member type is itself a reference, in which case
2088 // we're not going to refer to the member, but to what the member refers to.
2089 if (M->getMemberDecl()->getType()->isReferenceType())
2092 return EvalVal(M->getBase(), refVars);
2096 // Check that we don't return or take the address of a reference to a
2097 // temporary. This is only useful in C++.
2098 if (!E->isTypeDependent() && E->isRValue())
2101 // Everything else: we simply don't reason about them.
2107 //===--- CHECK: Floating-Point comparisons (-Wfloat-equal) ---------------===//
2109 /// Check for comparisons of floating point operands using != and ==.
2110 /// Issue a warning if these are no self-comparisons, as they are not likely
2111 /// to do what the programmer intended.
2112 void Sema::CheckFloatComparison(SourceLocation loc, Expr* lex, Expr *rex) {
2113 bool EmitWarning = true;
2115 Expr* LeftExprSansParen = lex->IgnoreParenImpCasts();
2116 Expr* RightExprSansParen = rex->IgnoreParenImpCasts();
2118 // Special case: check for x == x (which is OK).
2119 // Do not emit warnings for such cases.
2120 if (DeclRefExpr* DRL = dyn_cast<DeclRefExpr>(LeftExprSansParen))
2121 if (DeclRefExpr* DRR = dyn_cast<DeclRefExpr>(RightExprSansParen))
2122 if (DRL->getDecl() == DRR->getDecl())
2123 EmitWarning = false;
2126 // Special case: check for comparisons against literals that can be exactly
2127 // represented by APFloat. In such cases, do not emit a warning. This
2128 // is a heuristic: often comparison against such literals are used to
2129 // detect if a value in a variable has not changed. This clearly can
2130 // lead to false negatives.
2132 if (FloatingLiteral* FLL = dyn_cast<FloatingLiteral>(LeftExprSansParen)) {
2134 EmitWarning = false;
2136 if (FloatingLiteral* FLR = dyn_cast<FloatingLiteral>(RightExprSansParen)){
2138 EmitWarning = false;
2142 // Check for comparisons with builtin types.
2144 if (CallExpr* CL = dyn_cast<CallExpr>(LeftExprSansParen))
2145 if (CL->isBuiltinCall(Context))
2146 EmitWarning = false;
2149 if (CallExpr* CR = dyn_cast<CallExpr>(RightExprSansParen))
2150 if (CR->isBuiltinCall(Context))
2151 EmitWarning = false;
2153 // Emit the diagnostic.
2155 Diag(loc, diag::warn_floatingpoint_eq)
2156 << lex->getSourceRange() << rex->getSourceRange();
2159 //===--- CHECK: Integer mixed-sign comparisons (-Wsign-compare) --------===//
2160 //===--- CHECK: Lossy implicit conversions (-Wconversion) --------------===//
2164 /// Structure recording the 'active' range of an integer-valued
2167 /// The number of bits active in the int.
2170 /// True if the int is known not to have negative values.
2173 IntRange(unsigned Width, bool NonNegative)
2174 : Width(Width), NonNegative(NonNegative)
2177 /// Returns the range of the bool type.
2178 static IntRange forBoolType() {
2179 return IntRange(1, true);
2182 /// Returns the range of an opaque value of the given integral type.
2183 static IntRange forValueOfType(ASTContext &C, QualType T) {
2184 return forValueOfCanonicalType(C,
2185 T->getCanonicalTypeInternal().getTypePtr());
2188 /// Returns the range of an opaque value of a canonical integral type.
2189 static IntRange forValueOfCanonicalType(ASTContext &C, const Type *T) {
2190 assert(T->isCanonicalUnqualified());
2192 if (const VectorType *VT = dyn_cast<VectorType>(T))
2193 T = VT->getElementType().getTypePtr();
2194 if (const ComplexType *CT = dyn_cast<ComplexType>(T))
2195 T = CT->getElementType().getTypePtr();
2197 // For enum types, use the known bit width of the enumerators.
2198 if (const EnumType *ET = dyn_cast<EnumType>(T)) {
2199 EnumDecl *Enum = ET->getDecl();
2200 if (!Enum->isDefinition())
2201 return IntRange(C.getIntWidth(QualType(T, 0)), false);
2203 unsigned NumPositive = Enum->getNumPositiveBits();
2204 unsigned NumNegative = Enum->getNumNegativeBits();
2206 return IntRange(std::max(NumPositive, NumNegative), NumNegative == 0);
2209 const BuiltinType *BT = cast<BuiltinType>(T);
2210 assert(BT->isInteger());
2212 return IntRange(C.getIntWidth(QualType(T, 0)), BT->isUnsignedInteger());
2215 /// Returns the "target" range of a canonical integral type, i.e.
2216 /// the range of values expressible in the type.
2218 /// This matches forValueOfCanonicalType except that enums have the
2219 /// full range of their type, not the range of their enumerators.
2220 static IntRange forTargetOfCanonicalType(ASTContext &C, const Type *T) {
2221 assert(T->isCanonicalUnqualified());
2223 if (const VectorType *VT = dyn_cast<VectorType>(T))
2224 T = VT->getElementType().getTypePtr();
2225 if (const ComplexType *CT = dyn_cast<ComplexType>(T))
2226 T = CT->getElementType().getTypePtr();
2227 if (const EnumType *ET = dyn_cast<EnumType>(T))
2228 T = ET->getDecl()->getIntegerType().getTypePtr();
2230 const BuiltinType *BT = cast<BuiltinType>(T);
2231 assert(BT->isInteger());
2233 return IntRange(C.getIntWidth(QualType(T, 0)), BT->isUnsignedInteger());
2236 /// Returns the supremum of two ranges: i.e. their conservative merge.
2237 static IntRange join(IntRange L, IntRange R) {
2238 return IntRange(std::max(L.Width, R.Width),
2239 L.NonNegative && R.NonNegative);
2242 /// Returns the infinum of two ranges: i.e. their aggressive merge.
2243 static IntRange meet(IntRange L, IntRange R) {
2244 return IntRange(std::min(L.Width, R.Width),
2245 L.NonNegative || R.NonNegative);
2249 IntRange GetValueRange(ASTContext &C, llvm::APSInt &value, unsigned MaxWidth) {
2250 if (value.isSigned() && value.isNegative())
2251 return IntRange(value.getMinSignedBits(), false);
2253 if (value.getBitWidth() > MaxWidth)
2254 value = value.trunc(MaxWidth);
2256 // isNonNegative() just checks the sign bit without considering
2258 return IntRange(value.getActiveBits(), true);
2261 IntRange GetValueRange(ASTContext &C, APValue &result, QualType Ty,
2262 unsigned MaxWidth) {
2264 return GetValueRange(C, result.getInt(), MaxWidth);
2266 if (result.isVector()) {
2267 IntRange R = GetValueRange(C, result.getVectorElt(0), Ty, MaxWidth);
2268 for (unsigned i = 1, e = result.getVectorLength(); i != e; ++i) {
2269 IntRange El = GetValueRange(C, result.getVectorElt(i), Ty, MaxWidth);
2270 R = IntRange::join(R, El);
2275 if (result.isComplexInt()) {
2276 IntRange R = GetValueRange(C, result.getComplexIntReal(), MaxWidth);
2277 IntRange I = GetValueRange(C, result.getComplexIntImag(), MaxWidth);
2278 return IntRange::join(R, I);
2281 // This can happen with lossless casts to intptr_t of "based" lvalues.
2282 // Assume it might use arbitrary bits.
2283 // FIXME: The only reason we need to pass the type in here is to get
2284 // the sign right on this one case. It would be nice if APValue
2286 assert(result.isLValue());
2287 return IntRange(MaxWidth, Ty->isUnsignedIntegerType());
2290 /// Pseudo-evaluate the given integer expression, estimating the
2291 /// range of values it might take.
2293 /// \param MaxWidth - the width to which the value will be truncated
2294 IntRange GetExprRange(ASTContext &C, Expr *E, unsigned MaxWidth) {
2295 E = E->IgnoreParens();
2297 // Try a full evaluation first.
2298 Expr::EvalResult result;
2299 if (E->Evaluate(result, C))
2300 return GetValueRange(C, result.Val, E->getType(), MaxWidth);
2302 // I think we only want to look through implicit casts here; if the
2303 // user has an explicit widening cast, we should treat the value as
2304 // being of the new, wider type.
2305 if (ImplicitCastExpr *CE = dyn_cast<ImplicitCastExpr>(E)) {
2306 if (CE->getCastKind() == CK_NoOp)
2307 return GetExprRange(C, CE->getSubExpr(), MaxWidth);
2309 IntRange OutputTypeRange = IntRange::forValueOfType(C, CE->getType());
2311 bool isIntegerCast = (CE->getCastKind() == CK_IntegralCast);
2313 // Assume that non-integer casts can span the full range of the type.
2315 return OutputTypeRange;
2318 = GetExprRange(C, CE->getSubExpr(),
2319 std::min(MaxWidth, OutputTypeRange.Width));
2321 // Bail out if the subexpr's range is as wide as the cast type.
2322 if (SubRange.Width >= OutputTypeRange.Width)
2323 return OutputTypeRange;
2325 // Otherwise, we take the smaller width, and we're non-negative if
2326 // either the output type or the subexpr is.
2327 return IntRange(SubRange.Width,
2328 SubRange.NonNegative || OutputTypeRange.NonNegative);
2331 if (ConditionalOperator *CO = dyn_cast<ConditionalOperator>(E)) {
2332 // If we can fold the condition, just take that operand.
2334 if (CO->getCond()->EvaluateAsBooleanCondition(CondResult, C))
2335 return GetExprRange(C, CondResult ? CO->getTrueExpr()
2336 : CO->getFalseExpr(),
2339 // Otherwise, conservatively merge.
2340 IntRange L = GetExprRange(C, CO->getTrueExpr(), MaxWidth);
2341 IntRange R = GetExprRange(C, CO->getFalseExpr(), MaxWidth);
2342 return IntRange::join(L, R);
2345 if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) {
2346 switch (BO->getOpcode()) {
2348 // Boolean-valued operations are single-bit and positive.
2357 return IntRange::forBoolType();
2359 // The type of these compound assignments is the type of the LHS,
2360 // so the RHS is not necessarily an integer.
2366 return IntRange::forValueOfType(C, E->getType());
2368 // Operations with opaque sources are black-listed.
2371 return IntRange::forValueOfType(C, E->getType());
2373 // Bitwise-and uses the *infinum* of the two source ranges.
2376 return IntRange::meet(GetExprRange(C, BO->getLHS(), MaxWidth),
2377 GetExprRange(C, BO->getRHS(), MaxWidth));
2379 // Left shift gets black-listed based on a judgement call.
2381 // ...except that we want to treat '1 << (blah)' as logically
2382 // positive. It's an important idiom.
2383 if (IntegerLiteral *I
2384 = dyn_cast<IntegerLiteral>(BO->getLHS()->IgnoreParenCasts())) {
2385 if (I->getValue() == 1) {
2386 IntRange R = IntRange::forValueOfType(C, E->getType());
2387 return IntRange(R.Width, /*NonNegative*/ true);
2393 return IntRange::forValueOfType(C, E->getType());
2395 // Right shift by a constant can narrow its left argument.
2397 case BO_ShrAssign: {
2398 IntRange L = GetExprRange(C, BO->getLHS(), MaxWidth);
2400 // If the shift amount is a positive constant, drop the width by
2403 if (BO->getRHS()->isIntegerConstantExpr(shift, C) &&
2404 shift.isNonNegative()) {
2405 unsigned zext = shift.getZExtValue();
2406 if (zext >= L.Width)
2407 L.Width = (L.NonNegative ? 0 : 1);
2415 // Comma acts as its right operand.
2417 return GetExprRange(C, BO->getRHS(), MaxWidth);
2419 // Black-list pointer subtractions.
2421 if (BO->getLHS()->getType()->isPointerType())
2422 return IntRange::forValueOfType(C, E->getType());
2429 // Treat every other operator as if it were closed on the
2430 // narrowest type that encompasses both operands.
2431 IntRange L = GetExprRange(C, BO->getLHS(), MaxWidth);
2432 IntRange R = GetExprRange(C, BO->getRHS(), MaxWidth);
2433 return IntRange::join(L, R);
2436 if (UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) {
2437 switch (UO->getOpcode()) {
2438 // Boolean-valued operations are white-listed.
2440 return IntRange::forBoolType();
2442 // Operations with opaque sources are black-listed.
2444 case UO_AddrOf: // should be impossible
2445 return IntRange::forValueOfType(C, E->getType());
2448 return GetExprRange(C, UO->getSubExpr(), MaxWidth);
2452 if (dyn_cast<OffsetOfExpr>(E)) {
2453 IntRange::forValueOfType(C, E->getType());
2456 FieldDecl *BitField = E->getBitField();
2458 llvm::APSInt BitWidthAP = BitField->getBitWidth()->EvaluateAsInt(C);
2459 unsigned BitWidth = BitWidthAP.getZExtValue();
2461 return IntRange(BitWidth, BitField->getType()->isUnsignedIntegerType());
2464 return IntRange::forValueOfType(C, E->getType());
2467 IntRange GetExprRange(ASTContext &C, Expr *E) {
2468 return GetExprRange(C, E, C.getIntWidth(E->getType()));
2471 /// Checks whether the given value, which currently has the given
2472 /// source semantics, has the same value when coerced through the
2473 /// target semantics.
2474 bool IsSameFloatAfterCast(const llvm::APFloat &value,
2475 const llvm::fltSemantics &Src,
2476 const llvm::fltSemantics &Tgt) {
2477 llvm::APFloat truncated = value;
2480 truncated.convert(Src, llvm::APFloat::rmNearestTiesToEven, &ignored);
2481 truncated.convert(Tgt, llvm::APFloat::rmNearestTiesToEven, &ignored);
2483 return truncated.bitwiseIsEqual(value);
2486 /// Checks whether the given value, which currently has the given
2487 /// source semantics, has the same value when coerced through the
2488 /// target semantics.
2490 /// The value might be a vector of floats (or a complex number).
2491 bool IsSameFloatAfterCast(const APValue &value,
2492 const llvm::fltSemantics &Src,
2493 const llvm::fltSemantics &Tgt) {
2494 if (value.isFloat())
2495 return IsSameFloatAfterCast(value.getFloat(), Src, Tgt);
2497 if (value.isVector()) {
2498 for (unsigned i = 0, e = value.getVectorLength(); i != e; ++i)
2499 if (!IsSameFloatAfterCast(value.getVectorElt(i), Src, Tgt))
2504 assert(value.isComplexFloat());
2505 return (IsSameFloatAfterCast(value.getComplexFloatReal(), Src, Tgt) &&
2506 IsSameFloatAfterCast(value.getComplexFloatImag(), Src, Tgt));
2509 void AnalyzeImplicitConversions(Sema &S, Expr *E, SourceLocation CC);
2511 static bool IsZero(Sema &S, Expr *E) {
2512 // Suppress cases where we are comparing against an enum constant.
2513 if (const DeclRefExpr *DR =
2514 dyn_cast<DeclRefExpr>(E->IgnoreParenImpCasts()))
2515 if (isa<EnumConstantDecl>(DR->getDecl()))
2518 // Suppress cases where the '0' value is expanded from a macro.
2519 if (E->getLocStart().isMacroID())
2523 return E->isIntegerConstantExpr(Value, S.Context) && Value == 0;
2526 static bool HasEnumType(Expr *E) {
2527 // Strip off implicit integral promotions.
2528 while (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) {
2529 if (ICE->getCastKind() != CK_IntegralCast &&
2530 ICE->getCastKind() != CK_NoOp)
2532 E = ICE->getSubExpr();
2535 return E->getType()->isEnumeralType();
2538 void CheckTrivialUnsignedComparison(Sema &S, BinaryOperator *E) {
2539 BinaryOperatorKind op = E->getOpcode();
2540 if (E->isValueDependent())
2543 if (op == BO_LT && IsZero(S, E->getRHS())) {
2544 S.Diag(E->getOperatorLoc(), diag::warn_lunsigned_always_true_comparison)
2545 << "< 0" << "false" << HasEnumType(E->getLHS())
2546 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange();
2547 } else if (op == BO_GE && IsZero(S, E->getRHS())) {
2548 S.Diag(E->getOperatorLoc(), diag::warn_lunsigned_always_true_comparison)
2549 << ">= 0" << "true" << HasEnumType(E->getLHS())
2550 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange();
2551 } else if (op == BO_GT && IsZero(S, E->getLHS())) {
2552 S.Diag(E->getOperatorLoc(), diag::warn_runsigned_always_true_comparison)
2553 << "0 >" << "false" << HasEnumType(E->getRHS())
2554 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange();
2555 } else if (op == BO_LE && IsZero(S, E->getLHS())) {
2556 S.Diag(E->getOperatorLoc(), diag::warn_runsigned_always_true_comparison)
2557 << "0 <=" << "true" << HasEnumType(E->getRHS())
2558 << E->getLHS()->getSourceRange() << E->getRHS()->getSourceRange();
2562 /// Analyze the operands of the given comparison. Implements the
2563 /// fallback case from AnalyzeComparison.
2564 void AnalyzeImpConvsInComparison(Sema &S, BinaryOperator *E) {
2565 AnalyzeImplicitConversions(S, E->getLHS(), E->getOperatorLoc());
2566 AnalyzeImplicitConversions(S, E->getRHS(), E->getOperatorLoc());
2569 /// \brief Implements -Wsign-compare.
2571 /// \param lex the left-hand expression
2572 /// \param rex the right-hand expression
2573 /// \param OpLoc the location of the joining operator
2574 /// \param BinOpc binary opcode or 0
2575 void AnalyzeComparison(Sema &S, BinaryOperator *E) {
2576 // The type the comparison is being performed in.
2577 QualType T = E->getLHS()->getType();
2578 assert(S.Context.hasSameUnqualifiedType(T, E->getRHS()->getType())
2579 && "comparison with mismatched types");
2581 // We don't do anything special if this isn't an unsigned integral
2582 // comparison: we're only interested in integral comparisons, and
2583 // signed comparisons only happen in cases we don't care to warn about.
2585 // We also don't care about value-dependent expressions or expressions
2586 // whose result is a constant.
2587 if (!T->hasUnsignedIntegerRepresentation()
2588 || E->isValueDependent() || E->isIntegerConstantExpr(S.Context))
2589 return AnalyzeImpConvsInComparison(S, E);
2591 Expr *lex = E->getLHS()->IgnoreParenImpCasts();
2592 Expr *rex = E->getRHS()->IgnoreParenImpCasts();
2594 // Check to see if one of the (unmodified) operands is of different
2596 Expr *signedOperand, *unsignedOperand;
2597 if (lex->getType()->hasSignedIntegerRepresentation()) {
2598 assert(!rex->getType()->hasSignedIntegerRepresentation() &&
2599 "unsigned comparison between two signed integer expressions?");
2600 signedOperand = lex;
2601 unsignedOperand = rex;
2602 } else if (rex->getType()->hasSignedIntegerRepresentation()) {
2603 signedOperand = rex;
2604 unsignedOperand = lex;
2606 CheckTrivialUnsignedComparison(S, E);
2607 return AnalyzeImpConvsInComparison(S, E);
2610 // Otherwise, calculate the effective range of the signed operand.
2611 IntRange signedRange = GetExprRange(S.Context, signedOperand);
2613 // Go ahead and analyze implicit conversions in the operands. Note
2614 // that we skip the implicit conversions on both sides.
2615 AnalyzeImplicitConversions(S, lex, E->getOperatorLoc());
2616 AnalyzeImplicitConversions(S, rex, E->getOperatorLoc());
2618 // If the signed range is non-negative, -Wsign-compare won't fire,
2619 // but we should still check for comparisons which are always true
2621 if (signedRange.NonNegative)
2622 return CheckTrivialUnsignedComparison(S, E);
2624 // For (in)equality comparisons, if the unsigned operand is a
2625 // constant which cannot collide with a overflowed signed operand,
2626 // then reinterpreting the signed operand as unsigned will not
2627 // change the result of the comparison.
2628 if (E->isEqualityOp()) {
2629 unsigned comparisonWidth = S.Context.getIntWidth(T);
2630 IntRange unsignedRange = GetExprRange(S.Context, unsignedOperand);
2632 // We should never be unable to prove that the unsigned operand is
2634 assert(unsignedRange.NonNegative && "unsigned range includes negative?");
2636 if (unsignedRange.Width < comparisonWidth)
2640 S.Diag(E->getOperatorLoc(), diag::warn_mixed_sign_comparison)
2641 << lex->getType() << rex->getType()
2642 << lex->getSourceRange() << rex->getSourceRange();
2645 /// Analyzes an attempt to assign the given value to a bitfield.
2647 /// Returns true if there was something fishy about the attempt.
2648 bool AnalyzeBitFieldAssignment(Sema &S, FieldDecl *Bitfield, Expr *Init,
2649 SourceLocation InitLoc) {
2650 assert(Bitfield->isBitField());
2651 if (Bitfield->isInvalidDecl())
2654 // White-list bool bitfields.
2655 if (Bitfield->getType()->isBooleanType())
2658 // Ignore value- or type-dependent expressions.
2659 if (Bitfield->getBitWidth()->isValueDependent() ||
2660 Bitfield->getBitWidth()->isTypeDependent() ||
2661 Init->isValueDependent() ||
2662 Init->isTypeDependent())
2665 Expr *OriginalInit = Init->IgnoreParenImpCasts();
2667 llvm::APSInt Width(32);
2668 Expr::EvalResult InitValue;
2669 if (!Bitfield->getBitWidth()->isIntegerConstantExpr(Width, S.Context) ||
2670 !OriginalInit->Evaluate(InitValue, S.Context) ||
2671 !InitValue.Val.isInt())
2674 const llvm::APSInt &Value = InitValue.Val.getInt();
2675 unsigned OriginalWidth = Value.getBitWidth();
2676 unsigned FieldWidth = Width.getZExtValue();
2678 if (OriginalWidth <= FieldWidth)
2681 llvm::APSInt TruncatedValue = Value.trunc(FieldWidth);
2683 // It's fairly common to write values into signed bitfields
2684 // that, if sign-extended, would end up becoming a different
2685 // value. We don't want to warn about that.
2686 if (Value.isSigned() && Value.isNegative())
2687 TruncatedValue = TruncatedValue.sext(OriginalWidth);
2689 TruncatedValue = TruncatedValue.zext(OriginalWidth);
2691 if (Value == TruncatedValue)
2694 std::string PrettyValue = Value.toString(10);
2695 std::string PrettyTrunc = TruncatedValue.toString(10);
2697 S.Diag(InitLoc, diag::warn_impcast_bitfield_precision_constant)
2698 << PrettyValue << PrettyTrunc << OriginalInit->getType()
2699 << Init->getSourceRange();
2704 /// Analyze the given simple or compound assignment for warning-worthy
2706 void AnalyzeAssignment(Sema &S, BinaryOperator *E) {
2707 // Just recurse on the LHS.
2708 AnalyzeImplicitConversions(S, E->getLHS(), E->getOperatorLoc());
2710 // We want to recurse on the RHS as normal unless we're assigning to
2712 if (FieldDecl *Bitfield = E->getLHS()->getBitField()) {
2713 if (AnalyzeBitFieldAssignment(S, Bitfield, E->getRHS(),
2714 E->getOperatorLoc())) {
2715 // Recurse, ignoring any implicit conversions on the RHS.
2716 return AnalyzeImplicitConversions(S, E->getRHS()->IgnoreParenImpCasts(),
2717 E->getOperatorLoc());
2721 AnalyzeImplicitConversions(S, E->getRHS(), E->getOperatorLoc());
2724 /// Diagnose an implicit cast; purely a helper for CheckImplicitConversion.
2725 void DiagnoseImpCast(Sema &S, Expr *E, QualType T, SourceLocation CContext,
2727 S.Diag(E->getExprLoc(), diag)
2728 << E->getType() << T << E->getSourceRange() << SourceRange(CContext);
2731 std::string PrettyPrintInRange(const llvm::APSInt &Value, IntRange Range) {
2732 if (!Range.Width) return "0";
2734 llvm::APSInt ValueInRange = Value;
2735 ValueInRange.setIsSigned(!Range.NonNegative);
2736 ValueInRange = ValueInRange.trunc(Range.Width);
2737 return ValueInRange.toString(10);
2740 void CheckImplicitConversion(Sema &S, Expr *E, QualType T,
2741 SourceLocation CC, bool *ICContext = 0) {
2742 if (E->isTypeDependent() || E->isValueDependent()) return;
2744 const Type *Source = S.Context.getCanonicalType(E->getType()).getTypePtr();
2745 const Type *Target = S.Context.getCanonicalType(T).getTypePtr();
2746 if (Source == Target) return;
2747 if (Target->isDependentType()) return;
2749 // If the conversion context location is invalid or instantiated
2750 // from a system macro, don't complain.
2751 if (CC.isInvalid() ||
2752 (CC.isMacroID() && S.Context.getSourceManager().isInSystemHeader(
2753 S.Context.getSourceManager().getSpellingLoc(CC))))
2756 // Never diagnose implicit casts to bool.
2757 if (Target->isSpecificBuiltinType(BuiltinType::Bool))
2760 // Strip vector types.
2761 if (isa<VectorType>(Source)) {
2762 if (!isa<VectorType>(Target))
2763 return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_vector_scalar);
2765 Source = cast<VectorType>(Source)->getElementType().getTypePtr();
2766 Target = cast<VectorType>(Target)->getElementType().getTypePtr();
2769 // Strip complex types.
2770 if (isa<ComplexType>(Source)) {
2771 if (!isa<ComplexType>(Target))
2772 return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_complex_scalar);
2774 Source = cast<ComplexType>(Source)->getElementType().getTypePtr();
2775 Target = cast<ComplexType>(Target)->getElementType().getTypePtr();
2778 const BuiltinType *SourceBT = dyn_cast<BuiltinType>(Source);
2779 const BuiltinType *TargetBT = dyn_cast<BuiltinType>(Target);
2781 // If the source is floating point...
2782 if (SourceBT && SourceBT->isFloatingPoint()) {
2783 // ...and the target is floating point...
2784 if (TargetBT && TargetBT->isFloatingPoint()) {
2785 // ...then warn if we're dropping FP rank.
2787 // Builtin FP kinds are ordered by increasing FP rank.
2788 if (SourceBT->getKind() > TargetBT->getKind()) {
2789 // Don't warn about float constants that are precisely
2790 // representable in the target type.
2791 Expr::EvalResult result;
2792 if (E->Evaluate(result, S.Context)) {
2793 // Value might be a float, a float vector, or a float complex.
2794 if (IsSameFloatAfterCast(result.Val,
2795 S.Context.getFloatTypeSemantics(QualType(TargetBT, 0)),
2796 S.Context.getFloatTypeSemantics(QualType(SourceBT, 0))))
2800 DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_float_precision);
2805 // If the target is integral, always warn.
2806 if ((TargetBT && TargetBT->isInteger())) {
2807 Expr *InnerE = E->IgnoreParenImpCasts();
2808 if (FloatingLiteral *LiteralExpr = dyn_cast<FloatingLiteral>(InnerE)) {
2809 DiagnoseImpCast(S, LiteralExpr, T, CC,
2810 diag::warn_impcast_literal_float_to_integer);
2812 DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_float_integer);
2819 if (!Source->isIntegerType() || !Target->isIntegerType())
2822 IntRange SourceRange = GetExprRange(S.Context, E);
2823 IntRange TargetRange = IntRange::forTargetOfCanonicalType(S.Context, Target);
2825 if (SourceRange.Width > TargetRange.Width) {
2826 // If the source is a constant, use a default-on diagnostic.
2827 // TODO: this should happen for bitfield stores, too.
2828 llvm::APSInt Value(32);
2829 if (E->isIntegerConstantExpr(Value, S.Context)) {
2830 std::string PrettySourceValue = Value.toString(10);
2831 std::string PrettyTargetValue = PrettyPrintInRange(Value, TargetRange);
2833 S.Diag(E->getExprLoc(), diag::warn_impcast_integer_precision_constant)
2834 << PrettySourceValue << PrettyTargetValue
2835 << E->getType() << T << E->getSourceRange() << clang::SourceRange(CC);
2839 // People want to build with -Wshorten-64-to-32 and not -Wconversion
2840 // and by god we'll let them.
2841 if (SourceRange.Width == 64 && TargetRange.Width == 32)
2842 return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_integer_64_32);
2843 return DiagnoseImpCast(S, E, T, CC, diag::warn_impcast_integer_precision);
2846 if ((TargetRange.NonNegative && !SourceRange.NonNegative) ||
2847 (!TargetRange.NonNegative && SourceRange.NonNegative &&
2848 SourceRange.Width == TargetRange.Width)) {
2849 unsigned DiagID = diag::warn_impcast_integer_sign;
2851 // Traditionally, gcc has warned about this under -Wsign-compare.
2852 // We also want to warn about it in -Wconversion.
2853 // So if -Wconversion is off, use a completely identical diagnostic
2854 // in the sign-compare group.
2855 // The conditional-checking code will
2857 DiagID = diag::warn_impcast_integer_sign_conditional;
2861 return DiagnoseImpCast(S, E, T, CC, DiagID);
2867 void CheckConditionalOperator(Sema &S, ConditionalOperator *E, QualType T);
2869 void CheckConditionalOperand(Sema &S, Expr *E, QualType T,
2870 SourceLocation CC, bool &ICContext) {
2871 E = E->IgnoreParenImpCasts();
2873 if (isa<ConditionalOperator>(E))
2874 return CheckConditionalOperator(S, cast<ConditionalOperator>(E), T);
2876 AnalyzeImplicitConversions(S, E, CC);
2877 if (E->getType() != T)
2878 return CheckImplicitConversion(S, E, T, CC, &ICContext);
2882 void CheckConditionalOperator(Sema &S, ConditionalOperator *E, QualType T) {
2883 SourceLocation CC = E->getQuestionLoc();
2885 AnalyzeImplicitConversions(S, E->getCond(), CC);
2887 bool Suspicious = false;
2888 CheckConditionalOperand(S, E->getTrueExpr(), T, CC, Suspicious);
2889 CheckConditionalOperand(S, E->getFalseExpr(), T, CC, Suspicious);
2891 // If -Wconversion would have warned about either of the candidates
2892 // for a signedness conversion to the context type...
2893 if (!Suspicious) return;
2895 // ...but it's currently ignored...
2896 if (S.Diags.getDiagnosticLevel(diag::warn_impcast_integer_sign_conditional,
2900 // ...and -Wsign-compare isn't...
2901 if (!S.Diags.getDiagnosticLevel(diag::warn_mixed_sign_conditional, CC))
2904 // ...then check whether it would have warned about either of the
2905 // candidates for a signedness conversion to the condition type.
2906 if (E->getType() != T) {
2908 CheckImplicitConversion(S, E->getTrueExpr()->IgnoreParenImpCasts(),
2909 E->getType(), CC, &Suspicious);
2911 CheckImplicitConversion(S, E->getFalseExpr()->IgnoreParenImpCasts(),
2912 E->getType(), CC, &Suspicious);
2917 // If so, emit a diagnostic under -Wsign-compare.
2918 Expr *lex = E->getTrueExpr()->IgnoreParenImpCasts();
2919 Expr *rex = E->getFalseExpr()->IgnoreParenImpCasts();
2920 S.Diag(E->getQuestionLoc(), diag::warn_mixed_sign_conditional)
2921 << lex->getType() << rex->getType()
2922 << lex->getSourceRange() << rex->getSourceRange();
2925 /// AnalyzeImplicitConversions - Find and report any interesting
2926 /// implicit conversions in the given expression. There are a couple
2927 /// of competing diagnostics here, -Wconversion and -Wsign-compare.
2928 void AnalyzeImplicitConversions(Sema &S, Expr *OrigE, SourceLocation CC) {
2929 QualType T = OrigE->getType();
2930 Expr *E = OrigE->IgnoreParenImpCasts();
2932 // For conditional operators, we analyze the arguments as if they
2933 // were being fed directly into the output.
2934 if (isa<ConditionalOperator>(E)) {
2935 ConditionalOperator *CO = cast<ConditionalOperator>(E);
2936 CheckConditionalOperator(S, CO, T);
2940 // Go ahead and check any implicit conversions we might have skipped.
2941 // The non-canonical typecheck is just an optimization;
2942 // CheckImplicitConversion will filter out dead implicit conversions.
2943 if (E->getType() != T)
2944 CheckImplicitConversion(S, E, T, CC);
2946 // Now continue drilling into this expression.
2948 // Skip past explicit casts.
2949 if (isa<ExplicitCastExpr>(E)) {
2950 E = cast<ExplicitCastExpr>(E)->getSubExpr()->IgnoreParenImpCasts();
2951 return AnalyzeImplicitConversions(S, E, CC);
2954 if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) {
2955 // Do a somewhat different check with comparison operators.
2956 if (BO->isComparisonOp())
2957 return AnalyzeComparison(S, BO);
2959 // And with assignments and compound assignments.
2960 if (BO->isAssignmentOp())
2961 return AnalyzeAssignment(S, BO);
2964 // These break the otherwise-useful invariant below. Fortunately,
2965 // we don't really need to recurse into them, because any internal
2966 // expressions should have been analyzed already when they were
2967 // built into statements.
2968 if (isa<StmtExpr>(E)) return;
2970 // Don't descend into unevaluated contexts.
2971 if (isa<SizeOfAlignOfExpr>(E)) return;
2973 // Now just recurse over the expression's children.
2974 CC = E->getExprLoc();
2975 for (Stmt::child_range I = E->children(); I; ++I)
2976 AnalyzeImplicitConversions(S, cast<Expr>(*I), CC);
2979 } // end anonymous namespace
2981 /// Diagnoses "dangerous" implicit conversions within the given
2982 /// expression (which is a full expression). Implements -Wconversion
2983 /// and -Wsign-compare.
2985 /// \param CC the "context" location of the implicit conversion, i.e.
2986 /// the most location of the syntactic entity requiring the implicit
2988 void Sema::CheckImplicitConversions(Expr *E, SourceLocation CC) {
2989 // Don't diagnose in unevaluated contexts.
2990 if (ExprEvalContexts.back().Context == Sema::Unevaluated)
2993 // Don't diagnose for value- or type-dependent expressions.
2994 if (E->isTypeDependent() || E->isValueDependent())
2997 // This is not the right CC for (e.g.) a variable initialization.
2998 AnalyzeImplicitConversions(*this, E, CC);
3001 void Sema::CheckBitFieldInitialization(SourceLocation InitLoc,
3002 FieldDecl *BitField,
3004 (void) AnalyzeBitFieldAssignment(*this, BitField, Init, InitLoc);
3007 /// CheckParmsForFunctionDef - Check that the parameters of the given
3008 /// function are appropriate for the definition of a function. This
3009 /// takes care of any checks that cannot be performed on the
3010 /// declaration itself, e.g., that the types of each of the function
3011 /// parameters are complete.
3012 bool Sema::CheckParmsForFunctionDef(ParmVarDecl **P, ParmVarDecl **PEnd,
3013 bool CheckParameterNames) {
3014 bool HasInvalidParm = false;
3015 for (; P != PEnd; ++P) {
3016 ParmVarDecl *Param = *P;
3018 // C99 6.7.5.3p4: the parameters in a parameter type list in a
3019 // function declarator that is part of a function definition of
3020 // that function shall not have incomplete type.
3022 // This is also C++ [dcl.fct]p6.
3023 if (!Param->isInvalidDecl() &&
3024 RequireCompleteType(Param->getLocation(), Param->getType(),
3025 diag::err_typecheck_decl_incomplete_type)) {
3026 Param->setInvalidDecl();
3027 HasInvalidParm = true;
3030 // C99 6.9.1p5: If the declarator includes a parameter type list, the
3031 // declaration of each parameter shall include an identifier.
3032 if (CheckParameterNames &&
3033 Param->getIdentifier() == 0 &&
3034 !Param->isImplicit() &&
3035 !getLangOptions().CPlusPlus)
3036 Diag(Param->getLocation(), diag::err_parameter_name_omitted);
3039 // If the function declarator is not part of a definition of that
3040 // function, parameters may have incomplete type and may use the [*]
3041 // notation in their sequences of declarator specifiers to specify
3042 // variable length array types.
3043 QualType PType = Param->getOriginalType();
3044 if (const ArrayType *AT = Context.getAsArrayType(PType)) {
3045 if (AT->getSizeModifier() == ArrayType::Star) {
3046 // FIXME: This diagnosic should point the the '[*]' if source-location
3047 // information is added for it.
3048 Diag(Param->getLocation(), diag::err_array_star_in_function_definition);
3053 return HasInvalidParm;
3056 /// CheckCastAlign - Implements -Wcast-align, which warns when a
3057 /// pointer cast increases the alignment requirements.
3058 void Sema::CheckCastAlign(Expr *Op, QualType T, SourceRange TRange) {
3059 // This is actually a lot of work to potentially be doing on every
3060 // cast; don't do it if we're ignoring -Wcast_align (as is the default).
3061 if (getDiagnostics().getDiagnosticLevel(diag::warn_cast_align,
3063 == Diagnostic::Ignored)
3066 // Ignore dependent types.
3067 if (T->isDependentType() || Op->getType()->isDependentType())
3070 // Require that the destination be a pointer type.
3071 const PointerType *DestPtr = T->getAs<PointerType>();
3072 if (!DestPtr) return;
3074 // If the destination has alignment 1, we're done.
3075 QualType DestPointee = DestPtr->getPointeeType();
3076 if (DestPointee->isIncompleteType()) return;
3077 CharUnits DestAlign = Context.getTypeAlignInChars(DestPointee);
3078 if (DestAlign.isOne()) return;
3080 // Require that the source be a pointer type.
3081 const PointerType *SrcPtr = Op->getType()->getAs<PointerType>();
3082 if (!SrcPtr) return;
3083 QualType SrcPointee = SrcPtr->getPointeeType();
3085 // Whitelist casts from cv void*. We already implicitly
3086 // whitelisted casts to cv void*, since they have alignment 1.
3087 // Also whitelist casts involving incomplete types, which implicitly
3089 if (SrcPointee->isIncompleteType()) return;
3091 CharUnits SrcAlign = Context.getTypeAlignInChars(SrcPointee);
3092 if (SrcAlign >= DestAlign) return;
3094 Diag(TRange.getBegin(), diag::warn_cast_align)
3095 << Op->getType() << T
3096 << static_cast<unsigned>(SrcAlign.getQuantity())
3097 << static_cast<unsigned>(DestAlign.getQuantity())
3098 << TRange << Op->getSourceRange();
3101 void Sema::CheckArrayAccess(const clang::ArraySubscriptExpr *E) {
3102 const Expr *BaseExpr = E->getBase()->IgnoreParenImpCasts();
3103 const ConstantArrayType *ArrayTy =
3104 Context.getAsConstantArrayType(BaseExpr->getType());
3108 const Expr *IndexExpr = E->getIdx();
3109 if (IndexExpr->isValueDependent())
3112 if (!IndexExpr->isIntegerConstantExpr(index, Context))
3115 if (!index.isNegative()) {
3116 llvm::APInt size = ArrayTy->getSize();
3117 if (!size.isStrictlyPositive())
3119 if (size.getBitWidth() > index.getBitWidth())
3120 index = index.sext(size.getBitWidth());
3121 else if (size.getBitWidth() < index.getBitWidth())
3122 size = size.sext(index.getBitWidth());
3124 if (index.slt(size))
3127 Diag(E->getBase()->getLocStart(), diag::warn_array_index_exceeds_bounds)
3128 << index.toString(10, true) << size.toString(10, true)
3129 << IndexExpr->getSourceRange();
3131 Diag(E->getBase()->getLocStart(), diag::warn_array_index_precedes_bounds)
3132 << index.toString(10, true) << IndexExpr->getSourceRange();
3135 const NamedDecl *ND = NULL;
3136 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(BaseExpr))
3137 ND = dyn_cast<NamedDecl>(DRE->getDecl());
3138 if (const MemberExpr *ME = dyn_cast<MemberExpr>(BaseExpr))
3139 ND = dyn_cast<NamedDecl>(ME->getMemberDecl());
3141 Diag(ND->getLocStart(), diag::note_array_index_out_of_bounds)
3142 << ND->getDeclName();