1 //===--- SemaExceptionSpec.cpp - C++ Exception Specifications ---*- C++ -*-===//
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 provides Sema routines for C++ exception specification testing.
12 //===----------------------------------------------------------------------===//
14 #include "clang/Sema/SemaInternal.h"
15 #include "clang/AST/CXXInheritance.h"
16 #include "clang/AST/Expr.h"
17 #include "clang/AST/ExprCXX.h"
18 #include "clang/AST/TypeLoc.h"
19 #include "clang/Basic/Diagnostic.h"
20 #include "clang/Basic/SourceManager.h"
21 #include "clang/Lex/Preprocessor.h"
22 #include "llvm/ADT/SmallPtrSet.h"
23 #include "llvm/ADT/SmallString.h"
27 static const FunctionProtoType *GetUnderlyingFunction(QualType T)
29 if (const PointerType *PtrTy = T->getAs<PointerType>())
30 T = PtrTy->getPointeeType();
31 else if (const ReferenceType *RefTy = T->getAs<ReferenceType>())
32 T = RefTy->getPointeeType();
33 else if (const MemberPointerType *MPTy = T->getAs<MemberPointerType>())
34 T = MPTy->getPointeeType();
35 return T->getAs<FunctionProtoType>();
38 /// CheckSpecifiedExceptionType - Check if the given type is valid in an
39 /// exception specification. Incomplete types, or pointers to incomplete types
40 /// other than void are not allowed.
42 /// \param[in,out] T The exception type. This will be decayed to a pointer type
43 /// when the input is an array or a function type.
44 bool Sema::CheckSpecifiedExceptionType(QualType &T, const SourceRange &Range) {
45 // C++11 [except.spec]p2:
46 // A type cv T, "array of T", or "function returning T" denoted
47 // in an exception-specification is adjusted to type T, "pointer to T", or
48 // "pointer to function returning T", respectively.
50 // We also apply this rule in C++98.
52 T = Context.getArrayDecayedType(T);
53 else if (T->isFunctionType())
54 T = Context.getPointerType(T);
57 QualType PointeeT = T;
58 if (const PointerType *PT = T->getAs<PointerType>()) {
59 PointeeT = PT->getPointeeType();
62 // cv void* is explicitly permitted, despite being a pointer to an
64 if (PointeeT->isVoidType())
66 } else if (const ReferenceType *RT = T->getAs<ReferenceType>()) {
67 PointeeT = RT->getPointeeType();
70 if (RT->isRValueReferenceType()) {
71 // C++11 [except.spec]p2:
72 // A type denoted in an exception-specification shall not denote [...]
73 // an rvalue reference type.
74 Diag(Range.getBegin(), diag::err_rref_in_exception_spec)
80 // C++11 [except.spec]p2:
81 // A type denoted in an exception-specification shall not denote an
82 // incomplete type other than a class currently being defined [...].
83 // A type denoted in an exception-specification shall not denote a
84 // pointer or reference to an incomplete type, other than (cv) void* or a
85 // pointer or reference to a class currently being defined.
86 if (!(PointeeT->isRecordType() &&
87 PointeeT->getAs<RecordType>()->isBeingDefined()) &&
88 RequireCompleteType(Range.getBegin(), PointeeT,
89 diag::err_incomplete_in_exception_spec, Kind, Range))
95 /// CheckDistantExceptionSpec - Check if the given type is a pointer or pointer
96 /// to member to a function with an exception specification. This means that
97 /// it is invalid to add another level of indirection.
98 bool Sema::CheckDistantExceptionSpec(QualType T) {
99 if (const PointerType *PT = T->getAs<PointerType>())
100 T = PT->getPointeeType();
101 else if (const MemberPointerType *PT = T->getAs<MemberPointerType>())
102 T = PT->getPointeeType();
106 const FunctionProtoType *FnT = T->getAs<FunctionProtoType>();
110 return FnT->hasExceptionSpec();
113 const FunctionProtoType *
114 Sema::ResolveExceptionSpec(SourceLocation Loc, const FunctionProtoType *FPT) {
115 if (!isUnresolvedExceptionSpec(FPT->getExceptionSpecType()))
118 FunctionDecl *SourceDecl = FPT->getExceptionSpecDecl();
119 const FunctionProtoType *SourceFPT =
120 SourceDecl->getType()->castAs<FunctionProtoType>();
122 // If the exception specification has already been resolved, just return it.
123 if (!isUnresolvedExceptionSpec(SourceFPT->getExceptionSpecType()))
126 // Compute or instantiate the exception specification now.
127 if (SourceFPT->getExceptionSpecType() == EST_Unevaluated)
128 EvaluateImplicitExceptionSpec(Loc, cast<CXXMethodDecl>(SourceDecl));
130 InstantiateExceptionSpec(Loc, SourceDecl);
132 return SourceDecl->getType()->castAs<FunctionProtoType>();
135 /// Determine whether a function has an implicitly-generated exception
137 static bool hasImplicitExceptionSpec(FunctionDecl *Decl) {
138 if (!isa<CXXDestructorDecl>(Decl) &&
139 Decl->getDeclName().getCXXOverloadedOperator() != OO_Delete &&
140 Decl->getDeclName().getCXXOverloadedOperator() != OO_Array_Delete)
143 // If the user didn't declare the function, its exception specification must
145 if (!Decl->getTypeSourceInfo())
148 const FunctionProtoType *Ty =
149 Decl->getTypeSourceInfo()->getType()->getAs<FunctionProtoType>();
150 return !Ty->hasExceptionSpec();
153 bool Sema::CheckEquivalentExceptionSpec(FunctionDecl *Old, FunctionDecl *New) {
154 OverloadedOperatorKind OO = New->getDeclName().getCXXOverloadedOperator();
155 bool IsOperatorNew = OO == OO_New || OO == OO_Array_New;
156 bool MissingExceptionSpecification = false;
157 bool MissingEmptyExceptionSpecification = false;
158 unsigned DiagID = diag::err_mismatched_exception_spec;
159 if (getLangOpts().MicrosoftExt)
160 DiagID = diag::warn_mismatched_exception_spec;
162 // Check the types as written: they must match before any exception
163 // specification adjustment is applied.
164 if (!CheckEquivalentExceptionSpec(
165 PDiag(DiagID), PDiag(diag::note_previous_declaration),
166 Old->getType()->getAs<FunctionProtoType>(), Old->getLocation(),
167 New->getType()->getAs<FunctionProtoType>(), New->getLocation(),
168 &MissingExceptionSpecification, &MissingEmptyExceptionSpecification,
169 /*AllowNoexceptAllMatchWithNoSpec=*/true, IsOperatorNew)) {
170 // C++11 [except.spec]p4 [DR1492]:
171 // If a declaration of a function has an implicit
172 // exception-specification, other declarations of the function shall
173 // not specify an exception-specification.
174 if (getLangOpts().CPlusPlus11 &&
175 hasImplicitExceptionSpec(Old) != hasImplicitExceptionSpec(New)) {
176 Diag(New->getLocation(), diag::ext_implicit_exception_spec_mismatch)
177 << hasImplicitExceptionSpec(Old);
178 if (!Old->getLocation().isInvalid())
179 Diag(Old->getLocation(), diag::note_previous_declaration);
184 // The failure was something other than an missing exception
185 // specification; return an error.
186 if (!MissingExceptionSpecification)
189 const FunctionProtoType *NewProto =
190 New->getType()->castAs<FunctionProtoType>();
192 // The new function declaration is only missing an empty exception
193 // specification "throw()". If the throw() specification came from a
194 // function in a system header that has C linkage, just add an empty
195 // exception specification to the "new" declaration. This is an
196 // egregious workaround for glibc, which adds throw() specifications
197 // to many libc functions as an optimization. Unfortunately, that
198 // optimization isn't permitted by the C++ standard, so we're forced
199 // to work around it here.
200 if (MissingEmptyExceptionSpecification && NewProto &&
201 (Old->getLocation().isInvalid() ||
202 Context.getSourceManager().isInSystemHeader(Old->getLocation())) &&
204 FunctionProtoType::ExtProtoInfo EPI = NewProto->getExtProtoInfo();
205 EPI.ExceptionSpecType = EST_DynamicNone;
206 QualType NewType = Context.getFunctionType(NewProto->getResultType(),
207 NewProto->getArgTypes(), EPI);
208 New->setType(NewType);
212 const FunctionProtoType *OldProto =
213 Old->getType()->castAs<FunctionProtoType>();
215 FunctionProtoType::ExtProtoInfo EPI = NewProto->getExtProtoInfo();
216 EPI.ExceptionSpecType = OldProto->getExceptionSpecType();
217 if (EPI.ExceptionSpecType == EST_Dynamic) {
218 EPI.NumExceptions = OldProto->getNumExceptions();
219 EPI.Exceptions = OldProto->exception_begin();
220 } else if (EPI.ExceptionSpecType == EST_ComputedNoexcept) {
221 // FIXME: We can't just take the expression from the old prototype. It
222 // likely contains references to the old prototype's parameters.
225 // Update the type of the function with the appropriate exception
227 QualType NewType = Context.getFunctionType(NewProto->getResultType(),
228 NewProto->getArgTypes(), EPI);
229 New->setType(NewType);
231 // Warn about the lack of exception specification.
232 SmallString<128> ExceptionSpecString;
233 llvm::raw_svector_ostream OS(ExceptionSpecString);
234 switch (OldProto->getExceptionSpecType()) {
235 case EST_DynamicNone:
241 bool OnFirstException = true;
242 for (FunctionProtoType::exception_iterator E = OldProto->exception_begin(),
243 EEnd = OldProto->exception_end();
246 if (OnFirstException)
247 OnFirstException = false;
251 OS << E->getAsString(getPrintingPolicy());
257 case EST_BasicNoexcept:
261 case EST_ComputedNoexcept:
263 OldProto->getNoexceptExpr()->printPretty(OS, 0, getPrintingPolicy());
268 llvm_unreachable("This spec type is compatible with none.");
272 SourceLocation FixItLoc;
273 if (TypeSourceInfo *TSInfo = New->getTypeSourceInfo()) {
274 TypeLoc TL = TSInfo->getTypeLoc().IgnoreParens();
275 if (FunctionTypeLoc FTLoc = TL.getAs<FunctionTypeLoc>())
276 FixItLoc = PP.getLocForEndOfToken(FTLoc.getLocalRangeEnd());
279 if (FixItLoc.isInvalid())
280 Diag(New->getLocation(), diag::warn_missing_exception_specification)
283 // FIXME: This will get more complicated with C++0x
284 // late-specified return types.
285 Diag(New->getLocation(), diag::warn_missing_exception_specification)
287 << FixItHint::CreateInsertion(FixItLoc, " " + OS.str().str());
290 if (!Old->getLocation().isInvalid())
291 Diag(Old->getLocation(), diag::note_previous_declaration);
296 /// CheckEquivalentExceptionSpec - Check if the two types have equivalent
297 /// exception specifications. Exception specifications are equivalent if
298 /// they allow exactly the same set of exception types. It does not matter how
299 /// that is achieved. See C++ [except.spec]p2.
300 bool Sema::CheckEquivalentExceptionSpec(
301 const FunctionProtoType *Old, SourceLocation OldLoc,
302 const FunctionProtoType *New, SourceLocation NewLoc) {
303 unsigned DiagID = diag::err_mismatched_exception_spec;
304 if (getLangOpts().MicrosoftExt)
305 DiagID = diag::warn_mismatched_exception_spec;
306 return CheckEquivalentExceptionSpec(PDiag(DiagID),
307 PDiag(diag::note_previous_declaration),
308 Old, OldLoc, New, NewLoc);
311 /// CheckEquivalentExceptionSpec - Check if the two types have compatible
312 /// exception specifications. See C++ [except.spec]p3.
314 /// \return \c false if the exception specifications match, \c true if there is
315 /// a problem. If \c true is returned, either a diagnostic has already been
316 /// produced or \c *MissingExceptionSpecification is set to \c true.
317 bool Sema::CheckEquivalentExceptionSpec(const PartialDiagnostic &DiagID,
318 const PartialDiagnostic & NoteID,
319 const FunctionProtoType *Old,
320 SourceLocation OldLoc,
321 const FunctionProtoType *New,
322 SourceLocation NewLoc,
323 bool *MissingExceptionSpecification,
324 bool*MissingEmptyExceptionSpecification,
325 bool AllowNoexceptAllMatchWithNoSpec,
326 bool IsOperatorNew) {
327 // Just completely ignore this under -fno-exceptions.
328 if (!getLangOpts().CXXExceptions)
331 if (MissingExceptionSpecification)
332 *MissingExceptionSpecification = false;
334 if (MissingEmptyExceptionSpecification)
335 *MissingEmptyExceptionSpecification = false;
337 Old = ResolveExceptionSpec(NewLoc, Old);
340 New = ResolveExceptionSpec(NewLoc, New);
344 // C++0x [except.spec]p3: Two exception-specifications are compatible if:
345 // - both are non-throwing, regardless of their form,
346 // - both have the form noexcept(constant-expression) and the constant-
347 // expressions are equivalent,
348 // - both are dynamic-exception-specifications that have the same set of
351 // C++0x [except.spec]p12: An exception-specifcation is non-throwing if it is
352 // of the form throw(), noexcept, or noexcept(constant-expression) where the
353 // constant-expression yields true.
355 // C++0x [except.spec]p4: If any declaration of a function has an exception-
356 // specifier that is not a noexcept-specification allowing all exceptions,
357 // all declarations [...] of that function shall have a compatible
358 // exception-specification.
360 // That last point basically means that noexcept(false) matches no spec.
361 // It's considered when AllowNoexceptAllMatchWithNoSpec is true.
363 ExceptionSpecificationType OldEST = Old->getExceptionSpecType();
364 ExceptionSpecificationType NewEST = New->getExceptionSpecType();
366 assert(!isUnresolvedExceptionSpec(OldEST) &&
367 !isUnresolvedExceptionSpec(NewEST) &&
368 "Shouldn't see unknown exception specifications here");
370 // Shortcut the case where both have no spec.
371 if (OldEST == EST_None && NewEST == EST_None)
374 FunctionProtoType::NoexceptResult OldNR = Old->getNoexceptSpec(Context);
375 FunctionProtoType::NoexceptResult NewNR = New->getNoexceptSpec(Context);
376 if (OldNR == FunctionProtoType::NR_BadNoexcept ||
377 NewNR == FunctionProtoType::NR_BadNoexcept)
380 // Dependent noexcept specifiers are compatible with each other, but nothing
382 // One noexcept is compatible with another if the argument is the same
383 if (OldNR == NewNR &&
384 OldNR != FunctionProtoType::NR_NoNoexcept &&
385 NewNR != FunctionProtoType::NR_NoNoexcept)
387 if (OldNR != NewNR &&
388 OldNR != FunctionProtoType::NR_NoNoexcept &&
389 NewNR != FunctionProtoType::NR_NoNoexcept) {
390 Diag(NewLoc, DiagID);
391 if (NoteID.getDiagID() != 0)
392 Diag(OldLoc, NoteID);
396 // The MS extension throw(...) is compatible with itself.
397 if (OldEST == EST_MSAny && NewEST == EST_MSAny)
400 // It's also compatible with no spec.
401 if ((OldEST == EST_None && NewEST == EST_MSAny) ||
402 (OldEST == EST_MSAny && NewEST == EST_None))
405 // It's also compatible with noexcept(false).
406 if (OldEST == EST_MSAny && NewNR == FunctionProtoType::NR_Throw)
408 if (NewEST == EST_MSAny && OldNR == FunctionProtoType::NR_Throw)
411 // As described above, noexcept(false) matches no spec only for functions.
412 if (AllowNoexceptAllMatchWithNoSpec) {
413 if (OldEST == EST_None && NewNR == FunctionProtoType::NR_Throw)
415 if (NewEST == EST_None && OldNR == FunctionProtoType::NR_Throw)
419 // Any non-throwing specifications are compatible.
420 bool OldNonThrowing = OldNR == FunctionProtoType::NR_Nothrow ||
421 OldEST == EST_DynamicNone;
422 bool NewNonThrowing = NewNR == FunctionProtoType::NR_Nothrow ||
423 NewEST == EST_DynamicNone;
424 if (OldNonThrowing && NewNonThrowing)
427 // As a special compatibility feature, under C++0x we accept no spec and
428 // throw(std::bad_alloc) as equivalent for operator new and operator new[].
429 // This is because the implicit declaration changed, but old code would break.
430 if (getLangOpts().CPlusPlus11 && IsOperatorNew) {
431 const FunctionProtoType *WithExceptions = 0;
432 if (OldEST == EST_None && NewEST == EST_Dynamic)
433 WithExceptions = New;
434 else if (OldEST == EST_Dynamic && NewEST == EST_None)
435 WithExceptions = Old;
436 if (WithExceptions && WithExceptions->getNumExceptions() == 1) {
437 // One has no spec, the other throw(something). If that something is
438 // std::bad_alloc, all conditions are met.
439 QualType Exception = *WithExceptions->exception_begin();
440 if (CXXRecordDecl *ExRecord = Exception->getAsCXXRecordDecl()) {
441 IdentifierInfo* Name = ExRecord->getIdentifier();
442 if (Name && Name->getName() == "bad_alloc") {
443 // It's called bad_alloc, but is it in std?
444 DeclContext* DC = ExRecord->getDeclContext();
445 DC = DC->getEnclosingNamespaceContext();
446 if (NamespaceDecl* NS = dyn_cast<NamespaceDecl>(DC)) {
447 IdentifierInfo* NSName = NS->getIdentifier();
448 DC = DC->getParent();
449 if (NSName && NSName->getName() == "std" &&
450 DC->getEnclosingNamespaceContext()->isTranslationUnit()) {
459 // At this point, the only remaining valid case is two matching dynamic
460 // specifications. We return here unless both specifications are dynamic.
461 if (OldEST != EST_Dynamic || NewEST != EST_Dynamic) {
462 if (MissingExceptionSpecification && Old->hasExceptionSpec() &&
463 !New->hasExceptionSpec()) {
464 // The old type has an exception specification of some sort, but
465 // the new type does not.
466 *MissingExceptionSpecification = true;
468 if (MissingEmptyExceptionSpecification && OldNonThrowing) {
469 // The old type has a throw() or noexcept(true) exception specification
470 // and the new type has no exception specification, and the caller asked
471 // to handle this itself.
472 *MissingEmptyExceptionSpecification = true;
478 Diag(NewLoc, DiagID);
479 if (NoteID.getDiagID() != 0)
480 Diag(OldLoc, NoteID);
484 assert(OldEST == EST_Dynamic && NewEST == EST_Dynamic &&
485 "Exception compatibility logic error: non-dynamic spec slipped through.");
488 // Both have a dynamic exception spec. Collect the first set, then compare
490 llvm::SmallPtrSet<CanQualType, 8> OldTypes, NewTypes;
491 for (FunctionProtoType::exception_iterator I = Old->exception_begin(),
492 E = Old->exception_end(); I != E; ++I)
493 OldTypes.insert(Context.getCanonicalType(*I).getUnqualifiedType());
495 for (FunctionProtoType::exception_iterator I = New->exception_begin(),
496 E = New->exception_end(); I != E && Success; ++I) {
497 CanQualType TypePtr = Context.getCanonicalType(*I).getUnqualifiedType();
498 if(OldTypes.count(TypePtr))
499 NewTypes.insert(TypePtr);
504 Success = Success && OldTypes.size() == NewTypes.size();
509 Diag(NewLoc, DiagID);
510 if (NoteID.getDiagID() != 0)
511 Diag(OldLoc, NoteID);
515 /// CheckExceptionSpecSubset - Check whether the second function type's
516 /// exception specification is a subset (or equivalent) of the first function
517 /// type. This is used by override and pointer assignment checks.
518 bool Sema::CheckExceptionSpecSubset(
519 const PartialDiagnostic &DiagID, const PartialDiagnostic & NoteID,
520 const FunctionProtoType *Superset, SourceLocation SuperLoc,
521 const FunctionProtoType *Subset, SourceLocation SubLoc) {
523 // Just auto-succeed under -fno-exceptions.
524 if (!getLangOpts().CXXExceptions)
527 // FIXME: As usual, we could be more specific in our error messages, but
528 // that better waits until we've got types with source locations.
530 if (!SubLoc.isValid())
533 // Resolve the exception specifications, if needed.
534 Superset = ResolveExceptionSpec(SuperLoc, Superset);
537 Subset = ResolveExceptionSpec(SubLoc, Subset);
541 ExceptionSpecificationType SuperEST = Superset->getExceptionSpecType();
543 // If superset contains everything, we're done.
544 if (SuperEST == EST_None || SuperEST == EST_MSAny)
545 return CheckParamExceptionSpec(NoteID, Superset, SuperLoc, Subset, SubLoc);
547 // If there are dependent noexcept specs, assume everything is fine. Unlike
548 // with the equivalency check, this is safe in this case, because we don't
549 // want to merge declarations. Checks after instantiation will catch any
550 // omissions we make here.
551 // We also shortcut checking if a noexcept expression was bad.
553 FunctionProtoType::NoexceptResult SuperNR =Superset->getNoexceptSpec(Context);
554 if (SuperNR == FunctionProtoType::NR_BadNoexcept ||
555 SuperNR == FunctionProtoType::NR_Dependent)
558 // Another case of the superset containing everything.
559 if (SuperNR == FunctionProtoType::NR_Throw)
560 return CheckParamExceptionSpec(NoteID, Superset, SuperLoc, Subset, SubLoc);
562 ExceptionSpecificationType SubEST = Subset->getExceptionSpecType();
564 assert(!isUnresolvedExceptionSpec(SuperEST) &&
565 !isUnresolvedExceptionSpec(SubEST) &&
566 "Shouldn't see unknown exception specifications here");
568 // It does not. If the subset contains everything, we've failed.
569 if (SubEST == EST_None || SubEST == EST_MSAny) {
570 Diag(SubLoc, DiagID);
571 if (NoteID.getDiagID() != 0)
572 Diag(SuperLoc, NoteID);
576 FunctionProtoType::NoexceptResult SubNR = Subset->getNoexceptSpec(Context);
577 if (SubNR == FunctionProtoType::NR_BadNoexcept ||
578 SubNR == FunctionProtoType::NR_Dependent)
581 // Another case of the subset containing everything.
582 if (SubNR == FunctionProtoType::NR_Throw) {
583 Diag(SubLoc, DiagID);
584 if (NoteID.getDiagID() != 0)
585 Diag(SuperLoc, NoteID);
589 // If the subset contains nothing, we're done.
590 if (SubEST == EST_DynamicNone || SubNR == FunctionProtoType::NR_Nothrow)
591 return CheckParamExceptionSpec(NoteID, Superset, SuperLoc, Subset, SubLoc);
593 // Otherwise, if the superset contains nothing, we've failed.
594 if (SuperEST == EST_DynamicNone || SuperNR == FunctionProtoType::NR_Nothrow) {
595 Diag(SubLoc, DiagID);
596 if (NoteID.getDiagID() != 0)
597 Diag(SuperLoc, NoteID);
601 assert(SuperEST == EST_Dynamic && SubEST == EST_Dynamic &&
602 "Exception spec subset: non-dynamic case slipped through.");
604 // Neither contains everything or nothing. Do a proper comparison.
605 for (FunctionProtoType::exception_iterator SubI = Subset->exception_begin(),
606 SubE = Subset->exception_end(); SubI != SubE; ++SubI) {
607 // Take one type from the subset.
608 QualType CanonicalSubT = Context.getCanonicalType(*SubI);
609 // Unwrap pointers and references so that we can do checks within a class
610 // hierarchy. Don't unwrap member pointers; they don't have hierarchy
611 // conversions on the pointee.
612 bool SubIsPointer = false;
613 if (const ReferenceType *RefTy = CanonicalSubT->getAs<ReferenceType>())
614 CanonicalSubT = RefTy->getPointeeType();
615 if (const PointerType *PtrTy = CanonicalSubT->getAs<PointerType>()) {
616 CanonicalSubT = PtrTy->getPointeeType();
619 bool SubIsClass = CanonicalSubT->isRecordType();
620 CanonicalSubT = CanonicalSubT.getLocalUnqualifiedType();
622 CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/true,
623 /*DetectVirtual=*/false);
625 bool Contained = false;
626 // Make sure it's in the superset.
627 for (FunctionProtoType::exception_iterator SuperI =
628 Superset->exception_begin(), SuperE = Superset->exception_end();
629 SuperI != SuperE; ++SuperI) {
630 QualType CanonicalSuperT = Context.getCanonicalType(*SuperI);
631 // SubT must be SuperT or derived from it, or pointer or reference to
633 if (const ReferenceType *RefTy = CanonicalSuperT->getAs<ReferenceType>())
634 CanonicalSuperT = RefTy->getPointeeType();
636 if (const PointerType *PtrTy = CanonicalSuperT->getAs<PointerType>())
637 CanonicalSuperT = PtrTy->getPointeeType();
642 CanonicalSuperT = CanonicalSuperT.getLocalUnqualifiedType();
643 // If the types are the same, move on to the next type in the subset.
644 if (CanonicalSubT == CanonicalSuperT) {
649 // Otherwise we need to check the inheritance.
650 if (!SubIsClass || !CanonicalSuperT->isRecordType())
654 if (!IsDerivedFrom(CanonicalSubT, CanonicalSuperT, Paths))
657 if (Paths.isAmbiguous(Context.getCanonicalType(CanonicalSuperT)))
660 // Do this check from a context without privileges.
661 switch (CheckBaseClassAccess(SourceLocation(),
662 CanonicalSuperT, CanonicalSubT,
666 /*ForceUnprivileged*/ true)) {
667 case AR_accessible: break;
668 case AR_inaccessible: continue;
670 llvm_unreachable("access check dependent for unprivileged context");
672 llvm_unreachable("access check delayed in non-declaration");
679 Diag(SubLoc, DiagID);
680 if (NoteID.getDiagID() != 0)
681 Diag(SuperLoc, NoteID);
685 // We've run half the gauntlet.
686 return CheckParamExceptionSpec(NoteID, Superset, SuperLoc, Subset, SubLoc);
689 static bool CheckSpecForTypesEquivalent(Sema &S,
690 const PartialDiagnostic &DiagID, const PartialDiagnostic & NoteID,
691 QualType Target, SourceLocation TargetLoc,
692 QualType Source, SourceLocation SourceLoc)
694 const FunctionProtoType *TFunc = GetUnderlyingFunction(Target);
697 const FunctionProtoType *SFunc = GetUnderlyingFunction(Source);
701 return S.CheckEquivalentExceptionSpec(DiagID, NoteID, TFunc, TargetLoc,
705 /// CheckParamExceptionSpec - Check if the parameter and return types of the
706 /// two functions have equivalent exception specs. This is part of the
707 /// assignment and override compatibility check. We do not check the parameters
708 /// of parameter function pointers recursively, as no sane programmer would
709 /// even be able to write such a function type.
710 bool Sema::CheckParamExceptionSpec(const PartialDiagnostic & NoteID,
711 const FunctionProtoType *Target, SourceLocation TargetLoc,
712 const FunctionProtoType *Source, SourceLocation SourceLoc)
714 if (CheckSpecForTypesEquivalent(*this,
715 PDiag(diag::err_deep_exception_specs_differ) << 0,
717 Target->getResultType(), TargetLoc,
718 Source->getResultType(), SourceLoc))
721 // We shouldn't even be testing this unless the arguments are otherwise
723 assert(Target->getNumArgs() == Source->getNumArgs() &&
724 "Functions have different argument counts.");
725 for (unsigned i = 0, E = Target->getNumArgs(); i != E; ++i) {
726 if (CheckSpecForTypesEquivalent(*this,
727 PDiag(diag::err_deep_exception_specs_differ) << 1,
729 Target->getArgType(i), TargetLoc,
730 Source->getArgType(i), SourceLoc))
736 bool Sema::CheckExceptionSpecCompatibility(Expr *From, QualType ToType)
738 // First we check for applicability.
739 // Target type must be a function, function pointer or function reference.
740 const FunctionProtoType *ToFunc = GetUnderlyingFunction(ToType);
744 // SourceType must be a function or function pointer.
745 const FunctionProtoType *FromFunc = GetUnderlyingFunction(From->getType());
749 // Now we've got the correct types on both sides, check their compatibility.
750 // This means that the source of the conversion can only throw a subset of
751 // the exceptions of the target, and any exception specs on arguments or
752 // return types must be equivalent.
753 return CheckExceptionSpecSubset(PDiag(diag::err_incompatible_exception_specs),
755 From->getSourceRange().getBegin(),
756 FromFunc, SourceLocation());
759 bool Sema::CheckOverridingFunctionExceptionSpec(const CXXMethodDecl *New,
760 const CXXMethodDecl *Old) {
761 if (getLangOpts().CPlusPlus11 && isa<CXXDestructorDecl>(New)) {
762 // Don't check uninstantiated template destructors at all. We can only
763 // synthesize correct specs after the template is instantiated.
764 if (New->getParent()->isDependentType())
766 if (New->getParent()->isBeingDefined()) {
767 // The destructor might be updated once the definition is finished. So
768 // remember it and check later.
769 DelayedDestructorExceptionSpecChecks.push_back(std::make_pair(
770 cast<CXXDestructorDecl>(New), cast<CXXDestructorDecl>(Old)));
774 unsigned DiagID = diag::err_override_exception_spec;
775 if (getLangOpts().MicrosoftExt)
776 DiagID = diag::warn_override_exception_spec;
777 return CheckExceptionSpecSubset(PDiag(DiagID),
778 PDiag(diag::note_overridden_virtual_function),
779 Old->getType()->getAs<FunctionProtoType>(),
781 New->getType()->getAs<FunctionProtoType>(),
785 static CanThrowResult canSubExprsThrow(Sema &S, const Expr *CE) {
786 Expr *E = const_cast<Expr*>(CE);
787 CanThrowResult R = CT_Cannot;
788 for (Expr::child_range I = E->children(); I && R != CT_Can; ++I)
789 R = mergeCanThrow(R, S.canThrow(cast<Expr>(*I)));
793 static CanThrowResult canCalleeThrow(Sema &S, const Expr *E, const Decl *D) {
794 assert(D && "Expected decl");
796 // See if we can get a function type from the decl somehow.
797 const ValueDecl *VD = dyn_cast<ValueDecl>(D);
798 if (!VD) // If we have no clue what we're calling, assume the worst.
801 // As an extension, we assume that __attribute__((nothrow)) functions don't
803 if (isa<FunctionDecl>(D) && D->hasAttr<NoThrowAttr>())
806 QualType T = VD->getType();
807 const FunctionProtoType *FT;
808 if ((FT = T->getAs<FunctionProtoType>())) {
809 } else if (const PointerType *PT = T->getAs<PointerType>())
810 FT = PT->getPointeeType()->getAs<FunctionProtoType>();
811 else if (const ReferenceType *RT = T->getAs<ReferenceType>())
812 FT = RT->getPointeeType()->getAs<FunctionProtoType>();
813 else if (const MemberPointerType *MT = T->getAs<MemberPointerType>())
814 FT = MT->getPointeeType()->getAs<FunctionProtoType>();
815 else if (const BlockPointerType *BT = T->getAs<BlockPointerType>())
816 FT = BT->getPointeeType()->getAs<FunctionProtoType>();
821 FT = S.ResolveExceptionSpec(E->getLocStart(), FT);
825 return FT->isNothrow(S.Context) ? CT_Cannot : CT_Can;
828 static CanThrowResult canDynamicCastThrow(const CXXDynamicCastExpr *DC) {
829 if (DC->isTypeDependent())
832 if (!DC->getTypeAsWritten()->isReferenceType())
835 if (DC->getSubExpr()->isTypeDependent())
838 return DC->getCastKind() == clang::CK_Dynamic? CT_Can : CT_Cannot;
841 static CanThrowResult canTypeidThrow(Sema &S, const CXXTypeidExpr *DC) {
842 if (DC->isTypeOperand())
845 Expr *Op = DC->getExprOperand();
846 if (Op->isTypeDependent())
849 const RecordType *RT = Op->getType()->getAs<RecordType>();
853 if (!cast<CXXRecordDecl>(RT->getDecl())->isPolymorphic())
856 if (Op->Classify(S.Context).isPRValue())
862 CanThrowResult Sema::canThrow(const Expr *E) {
863 // C++ [expr.unary.noexcept]p3:
864 // [Can throw] if in a potentially-evaluated context the expression would
866 switch (E->getStmtClass()) {
867 case Expr::CXXThrowExprClass:
868 // - a potentially evaluated throw-expression
871 case Expr::CXXDynamicCastExprClass: {
872 // - a potentially evaluated dynamic_cast expression dynamic_cast<T>(v),
873 // where T is a reference type, that requires a run-time check
874 CanThrowResult CT = canDynamicCastThrow(cast<CXXDynamicCastExpr>(E));
877 return mergeCanThrow(CT, canSubExprsThrow(*this, E));
880 case Expr::CXXTypeidExprClass:
881 // - a potentially evaluated typeid expression applied to a glvalue
882 // expression whose type is a polymorphic class type
883 return canTypeidThrow(*this, cast<CXXTypeidExpr>(E));
885 // - a potentially evaluated call to a function, member function, function
886 // pointer, or member function pointer that does not have a non-throwing
887 // exception-specification
888 case Expr::CallExprClass:
889 case Expr::CXXMemberCallExprClass:
890 case Expr::CXXOperatorCallExprClass:
891 case Expr::UserDefinedLiteralClass: {
892 const CallExpr *CE = cast<CallExpr>(E);
894 if (E->isTypeDependent())
896 else if (isa<CXXPseudoDestructorExpr>(CE->getCallee()->IgnoreParens()))
898 else if (CE->getCalleeDecl())
899 CT = canCalleeThrow(*this, E, CE->getCalleeDecl());
904 return mergeCanThrow(CT, canSubExprsThrow(*this, E));
907 case Expr::CXXConstructExprClass:
908 case Expr::CXXTemporaryObjectExprClass: {
909 CanThrowResult CT = canCalleeThrow(*this, E,
910 cast<CXXConstructExpr>(E)->getConstructor());
913 return mergeCanThrow(CT, canSubExprsThrow(*this, E));
916 case Expr::LambdaExprClass: {
917 const LambdaExpr *Lambda = cast<LambdaExpr>(E);
918 CanThrowResult CT = CT_Cannot;
919 for (LambdaExpr::capture_init_iterator Cap = Lambda->capture_init_begin(),
920 CapEnd = Lambda->capture_init_end();
921 Cap != CapEnd; ++Cap)
922 CT = mergeCanThrow(CT, canThrow(*Cap));
926 case Expr::CXXNewExprClass: {
928 if (E->isTypeDependent())
931 CT = canCalleeThrow(*this, E, cast<CXXNewExpr>(E)->getOperatorNew());
934 return mergeCanThrow(CT, canSubExprsThrow(*this, E));
937 case Expr::CXXDeleteExprClass: {
939 QualType DTy = cast<CXXDeleteExpr>(E)->getDestroyedType();
940 if (DTy.isNull() || DTy->isDependentType()) {
943 CT = canCalleeThrow(*this, E,
944 cast<CXXDeleteExpr>(E)->getOperatorDelete());
945 if (const RecordType *RT = DTy->getAs<RecordType>()) {
946 const CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
947 const CXXDestructorDecl *DD = RD->getDestructor();
949 CT = mergeCanThrow(CT, canCalleeThrow(*this, E, DD));
954 return mergeCanThrow(CT, canSubExprsThrow(*this, E));
957 case Expr::CXXBindTemporaryExprClass: {
958 // The bound temporary has to be destroyed again, which might throw.
959 CanThrowResult CT = canCalleeThrow(*this, E,
960 cast<CXXBindTemporaryExpr>(E)->getTemporary()->getDestructor());
963 return mergeCanThrow(CT, canSubExprsThrow(*this, E));
966 // ObjC message sends are like function calls, but never have exception
968 case Expr::ObjCMessageExprClass:
969 case Expr::ObjCPropertyRefExprClass:
970 case Expr::ObjCSubscriptRefExprClass:
973 // All the ObjC literals that are implemented as calls are
974 // potentially throwing unless we decide to close off that
976 case Expr::ObjCArrayLiteralClass:
977 case Expr::ObjCDictionaryLiteralClass:
978 case Expr::ObjCBoxedExprClass:
981 // Many other things have subexpressions, so we have to test those.
983 case Expr::ConditionalOperatorClass:
984 case Expr::CompoundLiteralExprClass:
985 case Expr::CXXConstCastExprClass:
986 case Expr::CXXReinterpretCastExprClass:
987 case Expr::CXXStdInitializerListExprClass:
988 case Expr::DesignatedInitExprClass:
989 case Expr::ExprWithCleanupsClass:
990 case Expr::ExtVectorElementExprClass:
991 case Expr::InitListExprClass:
992 case Expr::MemberExprClass:
993 case Expr::ObjCIsaExprClass:
994 case Expr::ObjCIvarRefExprClass:
995 case Expr::ParenExprClass:
996 case Expr::ParenListExprClass:
997 case Expr::ShuffleVectorExprClass:
998 case Expr::ConvertVectorExprClass:
999 case Expr::VAArgExprClass:
1000 return canSubExprsThrow(*this, E);
1002 // Some might be dependent for other reasons.
1003 case Expr::ArraySubscriptExprClass:
1004 case Expr::BinaryOperatorClass:
1005 case Expr::CompoundAssignOperatorClass:
1006 case Expr::CStyleCastExprClass:
1007 case Expr::CXXStaticCastExprClass:
1008 case Expr::CXXFunctionalCastExprClass:
1009 case Expr::ImplicitCastExprClass:
1010 case Expr::MaterializeTemporaryExprClass:
1011 case Expr::UnaryOperatorClass: {
1012 CanThrowResult CT = E->isTypeDependent() ? CT_Dependent : CT_Cannot;
1013 return mergeCanThrow(CT, canSubExprsThrow(*this, E));
1016 // FIXME: We should handle StmtExpr, but that opens a MASSIVE can of worms.
1017 case Expr::StmtExprClass:
1020 case Expr::CXXDefaultArgExprClass:
1021 return canThrow(cast<CXXDefaultArgExpr>(E)->getExpr());
1023 case Expr::CXXDefaultInitExprClass:
1024 return canThrow(cast<CXXDefaultInitExpr>(E)->getExpr());
1026 case Expr::ChooseExprClass:
1027 if (E->isTypeDependent() || E->isValueDependent())
1028 return CT_Dependent;
1029 return canThrow(cast<ChooseExpr>(E)->getChosenSubExpr());
1031 case Expr::GenericSelectionExprClass:
1032 if (cast<GenericSelectionExpr>(E)->isResultDependent())
1033 return CT_Dependent;
1034 return canThrow(cast<GenericSelectionExpr>(E)->getResultExpr());
1036 // Some expressions are always dependent.
1037 case Expr::CXXDependentScopeMemberExprClass:
1038 case Expr::CXXUnresolvedConstructExprClass:
1039 case Expr::DependentScopeDeclRefExprClass:
1040 return CT_Dependent;
1042 case Expr::AsTypeExprClass:
1043 case Expr::BinaryConditionalOperatorClass:
1044 case Expr::BlockExprClass:
1045 case Expr::CUDAKernelCallExprClass:
1046 case Expr::DeclRefExprClass:
1047 case Expr::ObjCBridgedCastExprClass:
1048 case Expr::ObjCIndirectCopyRestoreExprClass:
1049 case Expr::ObjCProtocolExprClass:
1050 case Expr::ObjCSelectorExprClass:
1051 case Expr::OffsetOfExprClass:
1052 case Expr::PackExpansionExprClass:
1053 case Expr::PseudoObjectExprClass:
1054 case Expr::SubstNonTypeTemplateParmExprClass:
1055 case Expr::SubstNonTypeTemplateParmPackExprClass:
1056 case Expr::FunctionParmPackExprClass:
1057 case Expr::UnaryExprOrTypeTraitExprClass:
1058 case Expr::UnresolvedLookupExprClass:
1059 case Expr::UnresolvedMemberExprClass:
1060 // FIXME: Can any of the above throw? If so, when?
1063 case Expr::AddrLabelExprClass:
1064 case Expr::ArrayTypeTraitExprClass:
1065 case Expr::AtomicExprClass:
1066 case Expr::BinaryTypeTraitExprClass:
1067 case Expr::TypeTraitExprClass:
1068 case Expr::CXXBoolLiteralExprClass:
1069 case Expr::CXXNoexceptExprClass:
1070 case Expr::CXXNullPtrLiteralExprClass:
1071 case Expr::CXXPseudoDestructorExprClass:
1072 case Expr::CXXScalarValueInitExprClass:
1073 case Expr::CXXThisExprClass:
1074 case Expr::CXXUuidofExprClass:
1075 case Expr::CharacterLiteralClass:
1076 case Expr::ExpressionTraitExprClass:
1077 case Expr::FloatingLiteralClass:
1078 case Expr::GNUNullExprClass:
1079 case Expr::ImaginaryLiteralClass:
1080 case Expr::ImplicitValueInitExprClass:
1081 case Expr::IntegerLiteralClass:
1082 case Expr::ObjCEncodeExprClass:
1083 case Expr::ObjCStringLiteralClass:
1084 case Expr::ObjCBoolLiteralExprClass:
1085 case Expr::OpaqueValueExprClass:
1086 case Expr::PredefinedExprClass:
1087 case Expr::SizeOfPackExprClass:
1088 case Expr::StringLiteralClass:
1089 case Expr::UnaryTypeTraitExprClass:
1090 // These expressions can never throw.
1093 case Expr::MSPropertyRefExprClass:
1094 llvm_unreachable("Invalid class for expression");
1096 #define STMT(CLASS, PARENT) case Expr::CLASS##Class:
1097 #define STMT_RANGE(Base, First, Last)
1098 #define LAST_STMT_RANGE(BASE, FIRST, LAST)
1099 #define EXPR(CLASS, PARENT)
1100 #define ABSTRACT_STMT(STMT)
1101 #include "clang/AST/StmtNodes.inc"
1102 case Expr::NoStmtClass:
1103 llvm_unreachable("Invalid class for expression");
1105 llvm_unreachable("Bogus StmtClass");
1108 } // end namespace clang