clang  8.0.0svn
SemaExceptionSpec.cpp
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1 //===--- SemaExceptionSpec.cpp - C++ Exception Specifications ---*- C++ -*-===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file provides Sema routines for C++ exception specification testing.
11 //
12 //===----------------------------------------------------------------------===//
13 
17 #include "clang/AST/Expr.h"
18 #include "clang/AST/ExprCXX.h"
19 #include "clang/AST/TypeLoc.h"
20 #include "clang/Basic/Diagnostic.h"
22 #include "llvm/ADT/SmallPtrSet.h"
23 #include "llvm/ADT/SmallString.h"
24 
25 namespace clang {
26 
28 {
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>();
36 }
37 
38 /// HACK: libstdc++ has a bug where it shadows std::swap with a member
39 /// swap function then tries to call std::swap unqualified from the exception
40 /// specification of that function. This function detects whether we're in
41 /// such a case and turns off delay-parsing of exception specifications.
43  auto *RD = dyn_cast<CXXRecordDecl>(CurContext);
44 
45  // All the problem cases are member functions named "swap" within class
46  // templates declared directly within namespace std or std::__debug or
47  // std::__profile.
48  if (!RD || !RD->getIdentifier() || !RD->getDescribedClassTemplate() ||
49  !D.getIdentifier() || !D.getIdentifier()->isStr("swap"))
50  return false;
51 
52  auto *ND = dyn_cast<NamespaceDecl>(RD->getDeclContext());
53  if (!ND)
54  return false;
55 
56  bool IsInStd = ND->isStdNamespace();
57  if (!IsInStd) {
58  // This isn't a direct member of namespace std, but it might still be
59  // libstdc++'s std::__debug::array or std::__profile::array.
60  IdentifierInfo *II = ND->getIdentifier();
61  if (!II || !(II->isStr("__debug") || II->isStr("__profile")) ||
62  !ND->isInStdNamespace())
63  return false;
64  }
65 
66  // Only apply this hack within a system header.
68  return false;
69 
70  return llvm::StringSwitch<bool>(RD->getIdentifier()->getName())
71  .Case("array", true)
72  .Case("pair", IsInStd)
73  .Case("priority_queue", IsInStd)
74  .Case("stack", IsInStd)
75  .Case("queue", IsInStd)
76  .Default(false);
77 }
78 
80  Expr *NoexceptExpr,
82  // FIXME: This is bogus, a noexcept expression is not a condition.
83  ExprResult Converted = CheckBooleanCondition(NoexceptLoc, NoexceptExpr);
84  if (Converted.isInvalid())
85  return Converted;
86 
87  if (Converted.get()->isValueDependent()) {
89  return Converted;
90  }
91 
92  llvm::APSInt Result;
94  Converted.get(), &Result,
95  diag::err_noexcept_needs_constant_expression,
96  /*AllowFold*/ false);
97  if (!Converted.isInvalid())
98  EST = !Result ? EST_NoexceptFalse : EST_NoexceptTrue;
99  return Converted;
100 }
101 
102 /// CheckSpecifiedExceptionType - Check if the given type is valid in an
103 /// exception specification. Incomplete types, or pointers to incomplete types
104 /// other than void are not allowed.
105 ///
106 /// \param[in,out] T The exception type. This will be decayed to a pointer type
107 /// when the input is an array or a function type.
109  // C++11 [except.spec]p2:
110  // A type cv T, "array of T", or "function returning T" denoted
111  // in an exception-specification is adjusted to type T, "pointer to T", or
112  // "pointer to function returning T", respectively.
113  //
114  // We also apply this rule in C++98.
115  if (T->isArrayType())
117  else if (T->isFunctionType())
118  T = Context.getPointerType(T);
119 
120  int Kind = 0;
121  QualType PointeeT = T;
122  if (const PointerType *PT = T->getAs<PointerType>()) {
123  PointeeT = PT->getPointeeType();
124  Kind = 1;
125 
126  // cv void* is explicitly permitted, despite being a pointer to an
127  // incomplete type.
128  if (PointeeT->isVoidType())
129  return false;
130  } else if (const ReferenceType *RT = T->getAs<ReferenceType>()) {
131  PointeeT = RT->getPointeeType();
132  Kind = 2;
133 
134  if (RT->isRValueReferenceType()) {
135  // C++11 [except.spec]p2:
136  // A type denoted in an exception-specification shall not denote [...]
137  // an rvalue reference type.
138  Diag(Range.getBegin(), diag::err_rref_in_exception_spec)
139  << T << Range;
140  return true;
141  }
142  }
143 
144  // C++11 [except.spec]p2:
145  // A type denoted in an exception-specification shall not denote an
146  // incomplete type other than a class currently being defined [...].
147  // A type denoted in an exception-specification shall not denote a
148  // pointer or reference to an incomplete type, other than (cv) void* or a
149  // pointer or reference to a class currently being defined.
150  // In Microsoft mode, downgrade this to a warning.
151  unsigned DiagID = diag::err_incomplete_in_exception_spec;
152  bool ReturnValueOnError = true;
153  if (getLangOpts().MicrosoftExt) {
154  DiagID = diag::ext_incomplete_in_exception_spec;
155  ReturnValueOnError = false;
156  }
157  if (!(PointeeT->isRecordType() &&
158  PointeeT->getAs<RecordType>()->isBeingDefined()) &&
159  RequireCompleteType(Range.getBegin(), PointeeT, DiagID, Kind, Range))
160  return ReturnValueOnError;
161 
162  return false;
163 }
164 
165 /// CheckDistantExceptionSpec - Check if the given type is a pointer or pointer
166 /// to member to a function with an exception specification. This means that
167 /// it is invalid to add another level of indirection.
169  // C++17 removes this rule in favor of putting exception specifications into
170  // the type system.
171  if (getLangOpts().CPlusPlus17)
172  return false;
173 
174  if (const PointerType *PT = T->getAs<PointerType>())
175  T = PT->getPointeeType();
176  else if (const MemberPointerType *PT = T->getAs<MemberPointerType>())
177  T = PT->getPointeeType();
178  else
179  return false;
180 
181  const FunctionProtoType *FnT = T->getAs<FunctionProtoType>();
182  if (!FnT)
183  return false;
184 
185  return FnT->hasExceptionSpec();
186 }
187 
188 const FunctionProtoType *
190  if (FPT->getExceptionSpecType() == EST_Unparsed) {
191  Diag(Loc, diag::err_exception_spec_not_parsed);
192  return nullptr;
193  }
194 
196  return FPT;
197 
198  FunctionDecl *SourceDecl = FPT->getExceptionSpecDecl();
199  const FunctionProtoType *SourceFPT =
200  SourceDecl->getType()->castAs<FunctionProtoType>();
201 
202  // If the exception specification has already been resolved, just return it.
204  return SourceFPT;
205 
206  // Compute or instantiate the exception specification now.
207  if (SourceFPT->getExceptionSpecType() == EST_Unevaluated)
208  EvaluateImplicitExceptionSpec(Loc, cast<CXXMethodDecl>(SourceDecl));
209  else
210  InstantiateExceptionSpec(Loc, SourceDecl);
211 
212  const FunctionProtoType *Proto =
213  SourceDecl->getType()->castAs<FunctionProtoType>();
214  if (Proto->getExceptionSpecType() == clang::EST_Unparsed) {
215  Diag(Loc, diag::err_exception_spec_not_parsed);
216  Proto = nullptr;
217  }
218  return Proto;
219 }
220 
221 void
224  // If we've fully resolved the exception specification, notify listeners.
226  if (auto *Listener = getASTMutationListener())
227  Listener->ResolvedExceptionSpec(FD);
228 
229  for (FunctionDecl *Redecl : FD->redecls())
230  Context.adjustExceptionSpec(Redecl, ESI);
231 }
232 
233 static bool exceptionSpecNotKnownYet(const FunctionDecl *FD) {
234  auto *MD = dyn_cast<CXXMethodDecl>(FD);
235  if (!MD)
236  return false;
237 
238  auto EST = MD->getType()->castAs<FunctionProtoType>()->getExceptionSpecType();
239  return EST == EST_Unparsed ||
240  (EST == EST_Unevaluated && MD->getParent()->isBeingDefined());
241 }
242 
244  Sema &S, const PartialDiagnostic &DiagID, const PartialDiagnostic &NoteID,
245  const FunctionProtoType *Old, SourceLocation OldLoc,
246  const FunctionProtoType *New, SourceLocation NewLoc,
247  bool *MissingExceptionSpecification = nullptr,
248  bool *MissingEmptyExceptionSpecification = nullptr,
249  bool AllowNoexceptAllMatchWithNoSpec = false, bool IsOperatorNew = false);
250 
251 /// Determine whether a function has an implicitly-generated exception
252 /// specification.
254  if (!isa<CXXDestructorDecl>(Decl) &&
255  Decl->getDeclName().getCXXOverloadedOperator() != OO_Delete &&
256  Decl->getDeclName().getCXXOverloadedOperator() != OO_Array_Delete)
257  return false;
258 
259  // For a function that the user didn't declare:
260  // - if this is a destructor, its exception specification is implicit.
261  // - if this is 'operator delete' or 'operator delete[]', the exception
262  // specification is as-if an explicit exception specification was given
263  // (per [basic.stc.dynamic]p2).
264  if (!Decl->getTypeSourceInfo())
265  return isa<CXXDestructorDecl>(Decl);
266 
267  const FunctionProtoType *Ty =
269  return !Ty->hasExceptionSpec();
270 }
271 
273  // Just completely ignore this under -fno-exceptions prior to C++17.
274  // In C++17 onwards, the exception specification is part of the type and
275  // we will diagnose mismatches anyway, so it's better to check for them here.
276  if (!getLangOpts().CXXExceptions && !getLangOpts().CPlusPlus17)
277  return false;
278 
280  bool IsOperatorNew = OO == OO_New || OO == OO_Array_New;
281  bool MissingExceptionSpecification = false;
282  bool MissingEmptyExceptionSpecification = false;
283 
284  unsigned DiagID = diag::err_mismatched_exception_spec;
285  bool ReturnValueOnError = true;
286  if (getLangOpts().MicrosoftExt) {
287  DiagID = diag::ext_mismatched_exception_spec;
288  ReturnValueOnError = false;
289  }
290 
291  // If we're befriending a member function of a class that's currently being
292  // defined, we might not be able to work out its exception specification yet.
293  // If not, defer the check until later.
295  DelayedEquivalentExceptionSpecChecks.push_back({New, Old});
296  return false;
297  }
298 
299  // Check the types as written: they must match before any exception
300  // specification adjustment is applied.
302  *this, PDiag(DiagID), PDiag(diag::note_previous_declaration),
303  Old->getType()->getAs<FunctionProtoType>(), Old->getLocation(),
304  New->getType()->getAs<FunctionProtoType>(), New->getLocation(),
305  &MissingExceptionSpecification, &MissingEmptyExceptionSpecification,
306  /*AllowNoexceptAllMatchWithNoSpec=*/true, IsOperatorNew)) {
307  // C++11 [except.spec]p4 [DR1492]:
308  // If a declaration of a function has an implicit
309  // exception-specification, other declarations of the function shall
310  // not specify an exception-specification.
311  if (getLangOpts().CPlusPlus11 && getLangOpts().CXXExceptions &&
313  Diag(New->getLocation(), diag::ext_implicit_exception_spec_mismatch)
314  << hasImplicitExceptionSpec(Old);
315  if (Old->getLocation().isValid())
316  Diag(Old->getLocation(), diag::note_previous_declaration);
317  }
318  return false;
319  }
320 
321  // The failure was something other than an missing exception
322  // specification; return an error, except in MS mode where this is a warning.
323  if (!MissingExceptionSpecification)
324  return ReturnValueOnError;
325 
326  const FunctionProtoType *NewProto =
327  New->getType()->castAs<FunctionProtoType>();
328 
329  // The new function declaration is only missing an empty exception
330  // specification "throw()". If the throw() specification came from a
331  // function in a system header that has C linkage, just add an empty
332  // exception specification to the "new" declaration. Note that C library
333  // implementations are permitted to add these nothrow exception
334  // specifications.
335  //
336  // Likewise if the old function is a builtin.
337  if (MissingEmptyExceptionSpecification && NewProto &&
338  (Old->getLocation().isInvalid() ||
340  Old->getBuiltinID()) &&
341  Old->isExternC()) {
343  NewProto->getReturnType(), NewProto->getParamTypes(),
345  return false;
346  }
347 
348  const FunctionProtoType *OldProto =
349  Old->getType()->castAs<FunctionProtoType>();
350 
352  if (ESI.Type == EST_Dynamic) {
353  // FIXME: What if the exceptions are described in terms of the old
354  // prototype's parameters?
355  ESI.Exceptions = OldProto->exceptions();
356  }
357 
358  if (ESI.Type == EST_NoexceptFalse)
359  ESI.Type = EST_None;
360  if (ESI.Type == EST_NoexceptTrue)
361  ESI.Type = EST_BasicNoexcept;
362 
363  // For dependent noexcept, we can't just take the expression from the old
364  // prototype. It likely contains references to the old prototype's parameters.
365  if (ESI.Type == EST_DependentNoexcept) {
366  New->setInvalidDecl();
367  } else {
368  // Update the type of the function with the appropriate exception
369  // specification.
371  NewProto->getReturnType(), NewProto->getParamTypes(),
372  NewProto->getExtProtoInfo().withExceptionSpec(ESI)));
373  }
374 
375  if (getLangOpts().MicrosoftExt && ESI.Type != EST_DependentNoexcept) {
376  // Allow missing exception specifications in redeclarations as an extension.
377  DiagID = diag::ext_ms_missing_exception_specification;
378  ReturnValueOnError = false;
379  } else if (New->isReplaceableGlobalAllocationFunction() &&
380  ESI.Type != EST_DependentNoexcept) {
381  // Allow missing exception specifications in redeclarations as an extension,
382  // when declaring a replaceable global allocation function.
383  DiagID = diag::ext_missing_exception_specification;
384  ReturnValueOnError = false;
385  } else {
386  DiagID = diag::err_missing_exception_specification;
387  ReturnValueOnError = true;
388  }
389 
390  // Warn about the lack of exception specification.
391  SmallString<128> ExceptionSpecString;
392  llvm::raw_svector_ostream OS(ExceptionSpecString);
393  switch (OldProto->getExceptionSpecType()) {
394  case EST_DynamicNone:
395  OS << "throw()";
396  break;
397 
398  case EST_Dynamic: {
399  OS << "throw(";
400  bool OnFirstException = true;
401  for (const auto &E : OldProto->exceptions()) {
402  if (OnFirstException)
403  OnFirstException = false;
404  else
405  OS << ", ";
406 
407  OS << E.getAsString(getPrintingPolicy());
408  }
409  OS << ")";
410  break;
411  }
412 
413  case EST_BasicNoexcept:
414  OS << "noexcept";
415  break;
416 
418  case EST_NoexceptFalse:
419  case EST_NoexceptTrue:
420  OS << "noexcept(";
421  assert(OldProto->getNoexceptExpr() != nullptr && "Expected non-null Expr");
422  OldProto->getNoexceptExpr()->printPretty(OS, nullptr, getPrintingPolicy());
423  OS << ")";
424  break;
425 
426  default:
427  llvm_unreachable("This spec type is compatible with none.");
428  }
429 
430  SourceLocation FixItLoc;
431  if (TypeSourceInfo *TSInfo = New->getTypeSourceInfo()) {
432  TypeLoc TL = TSInfo->getTypeLoc().IgnoreParens();
433  // FIXME: Preserve enough information so that we can produce a correct fixit
434  // location when there is a trailing return type.
435  if (auto FTLoc = TL.getAs<FunctionProtoTypeLoc>())
436  if (!FTLoc.getTypePtr()->hasTrailingReturn())
437  FixItLoc = getLocForEndOfToken(FTLoc.getLocalRangeEnd());
438  }
439 
440  if (FixItLoc.isInvalid())
441  Diag(New->getLocation(), DiagID)
442  << New << OS.str();
443  else {
444  Diag(New->getLocation(), DiagID)
445  << New << OS.str()
446  << FixItHint::CreateInsertion(FixItLoc, " " + OS.str().str());
447  }
448 
449  if (Old->getLocation().isValid())
450  Diag(Old->getLocation(), diag::note_previous_declaration);
451 
452  return ReturnValueOnError;
453 }
454 
455 /// CheckEquivalentExceptionSpec - Check if the two types have equivalent
456 /// exception specifications. Exception specifications are equivalent if
457 /// they allow exactly the same set of exception types. It does not matter how
458 /// that is achieved. See C++ [except.spec]p2.
460  const FunctionProtoType *Old, SourceLocation OldLoc,
461  const FunctionProtoType *New, SourceLocation NewLoc) {
462  if (!getLangOpts().CXXExceptions)
463  return false;
464 
465  unsigned DiagID = diag::err_mismatched_exception_spec;
466  if (getLangOpts().MicrosoftExt)
467  DiagID = diag::ext_mismatched_exception_spec;
469  *this, PDiag(DiagID), PDiag(diag::note_previous_declaration),
470  Old, OldLoc, New, NewLoc);
471 
472  // In Microsoft mode, mismatching exception specifications just cause a warning.
473  if (getLangOpts().MicrosoftExt)
474  return false;
475  return Result;
476 }
477 
478 /// CheckEquivalentExceptionSpec - Check if the two types have compatible
479 /// exception specifications. See C++ [except.spec]p3.
480 ///
481 /// \return \c false if the exception specifications match, \c true if there is
482 /// a problem. If \c true is returned, either a diagnostic has already been
483 /// produced or \c *MissingExceptionSpecification is set to \c true.
485  Sema &S, const PartialDiagnostic &DiagID, const PartialDiagnostic &NoteID,
486  const FunctionProtoType *Old, SourceLocation OldLoc,
487  const FunctionProtoType *New, SourceLocation NewLoc,
488  bool *MissingExceptionSpecification,
489  bool *MissingEmptyExceptionSpecification,
490  bool AllowNoexceptAllMatchWithNoSpec, bool IsOperatorNew) {
491  if (MissingExceptionSpecification)
492  *MissingExceptionSpecification = false;
493 
494  if (MissingEmptyExceptionSpecification)
495  *MissingEmptyExceptionSpecification = false;
496 
497  Old = S.ResolveExceptionSpec(NewLoc, Old);
498  if (!Old)
499  return false;
500  New = S.ResolveExceptionSpec(NewLoc, New);
501  if (!New)
502  return false;
503 
504  // C++0x [except.spec]p3: Two exception-specifications are compatible if:
505  // - both are non-throwing, regardless of their form,
506  // - both have the form noexcept(constant-expression) and the constant-
507  // expressions are equivalent,
508  // - both are dynamic-exception-specifications that have the same set of
509  // adjusted types.
510  //
511  // C++0x [except.spec]p12: An exception-specification is non-throwing if it is
512  // of the form throw(), noexcept, or noexcept(constant-expression) where the
513  // constant-expression yields true.
514  //
515  // C++0x [except.spec]p4: If any declaration of a function has an exception-
516  // specifier that is not a noexcept-specification allowing all exceptions,
517  // all declarations [...] of that function shall have a compatible
518  // exception-specification.
519  //
520  // That last point basically means that noexcept(false) matches no spec.
521  // It's considered when AllowNoexceptAllMatchWithNoSpec is true.
522 
525 
526  assert(!isUnresolvedExceptionSpec(OldEST) &&
527  !isUnresolvedExceptionSpec(NewEST) &&
528  "Shouldn't see unknown exception specifications here");
529 
530  CanThrowResult OldCanThrow = Old->canThrow();
531  CanThrowResult NewCanThrow = New->canThrow();
532 
533  // Any non-throwing specifications are compatible.
534  if (OldCanThrow == CT_Cannot && NewCanThrow == CT_Cannot)
535  return false;
536 
537  // Any throws-anything specifications are usually compatible.
538  if (OldCanThrow == CT_Can && OldEST != EST_Dynamic &&
539  NewCanThrow == CT_Can && NewEST != EST_Dynamic) {
540  // The exception is that the absence of an exception specification only
541  // matches noexcept(false) for functions, as described above.
542  if (!AllowNoexceptAllMatchWithNoSpec &&
543  ((OldEST == EST_None && NewEST == EST_NoexceptFalse) ||
544  (OldEST == EST_NoexceptFalse && NewEST == EST_None))) {
545  // This is the disallowed case.
546  } else {
547  return false;
548  }
549  }
550 
551  // C++14 [except.spec]p3:
552  // Two exception-specifications are compatible if [...] both have the form
553  // noexcept(constant-expression) and the constant-expressions are equivalent
554  if (OldEST == EST_DependentNoexcept && NewEST == EST_DependentNoexcept) {
555  llvm::FoldingSetNodeID OldFSN, NewFSN;
556  Old->getNoexceptExpr()->Profile(OldFSN, S.Context, true);
557  New->getNoexceptExpr()->Profile(NewFSN, S.Context, true);
558  if (OldFSN == NewFSN)
559  return false;
560  }
561 
562  // Dynamic exception specifications with the same set of adjusted types
563  // are compatible.
564  if (OldEST == EST_Dynamic && NewEST == EST_Dynamic) {
565  bool Success = true;
566  // Both have a dynamic exception spec. Collect the first set, then compare
567  // to the second.
568  llvm::SmallPtrSet<CanQualType, 8> OldTypes, NewTypes;
569  for (const auto &I : Old->exceptions())
570  OldTypes.insert(S.Context.getCanonicalType(I).getUnqualifiedType());
571 
572  for (const auto &I : New->exceptions()) {
574  if (OldTypes.count(TypePtr))
575  NewTypes.insert(TypePtr);
576  else {
577  Success = false;
578  break;
579  }
580  }
581 
582  if (Success && OldTypes.size() == NewTypes.size())
583  return false;
584  }
585 
586  // As a special compatibility feature, under C++0x we accept no spec and
587  // throw(std::bad_alloc) as equivalent for operator new and operator new[].
588  // This is because the implicit declaration changed, but old code would break.
589  if (S.getLangOpts().CPlusPlus11 && IsOperatorNew) {
590  const FunctionProtoType *WithExceptions = nullptr;
591  if (OldEST == EST_None && NewEST == EST_Dynamic)
592  WithExceptions = New;
593  else if (OldEST == EST_Dynamic && NewEST == EST_None)
594  WithExceptions = Old;
595  if (WithExceptions && WithExceptions->getNumExceptions() == 1) {
596  // One has no spec, the other throw(something). If that something is
597  // std::bad_alloc, all conditions are met.
598  QualType Exception = *WithExceptions->exception_begin();
599  if (CXXRecordDecl *ExRecord = Exception->getAsCXXRecordDecl()) {
600  IdentifierInfo* Name = ExRecord->getIdentifier();
601  if (Name && Name->getName() == "bad_alloc") {
602  // It's called bad_alloc, but is it in std?
603  if (ExRecord->isInStdNamespace()) {
604  return false;
605  }
606  }
607  }
608  }
609  }
610 
611  // If the caller wants to handle the case that the new function is
612  // incompatible due to a missing exception specification, let it.
613  if (MissingExceptionSpecification && OldEST != EST_None &&
614  NewEST == EST_None) {
615  // The old type has an exception specification of some sort, but
616  // the new type does not.
617  *MissingExceptionSpecification = true;
618 
619  if (MissingEmptyExceptionSpecification && OldCanThrow == CT_Cannot) {
620  // The old type has a throw() or noexcept(true) exception specification
621  // and the new type has no exception specification, and the caller asked
622  // to handle this itself.
623  *MissingEmptyExceptionSpecification = true;
624  }
625 
626  return true;
627  }
628 
629  S.Diag(NewLoc, DiagID);
630  if (NoteID.getDiagID() != 0 && OldLoc.isValid())
631  S.Diag(OldLoc, NoteID);
632  return true;
633 }
634 
636  const PartialDiagnostic &NoteID,
637  const FunctionProtoType *Old,
638  SourceLocation OldLoc,
639  const FunctionProtoType *New,
640  SourceLocation NewLoc) {
641  if (!getLangOpts().CXXExceptions)
642  return false;
643  return CheckEquivalentExceptionSpecImpl(*this, DiagID, NoteID, Old, OldLoc,
644  New, NewLoc);
645 }
646 
647 bool Sema::handlerCanCatch(QualType HandlerType, QualType ExceptionType) {
648  // [except.handle]p3:
649  // A handler is a match for an exception object of type E if:
650 
651  // HandlerType must be ExceptionType or derived from it, or pointer or
652  // reference to such types.
653  const ReferenceType *RefTy = HandlerType->getAs<ReferenceType>();
654  if (RefTy)
655  HandlerType = RefTy->getPointeeType();
656 
657  // -- the handler is of type cv T or cv T& and E and T are the same type
658  if (Context.hasSameUnqualifiedType(ExceptionType, HandlerType))
659  return true;
660 
661  // FIXME: ObjC pointer types?
662  if (HandlerType->isPointerType() || HandlerType->isMemberPointerType()) {
663  if (RefTy && (!HandlerType.isConstQualified() ||
664  HandlerType.isVolatileQualified()))
665  return false;
666 
667  // -- the handler is of type cv T or const T& where T is a pointer or
668  // pointer to member type and E is std::nullptr_t
669  if (ExceptionType->isNullPtrType())
670  return true;
671 
672  // -- the handler is of type cv T or const T& where T is a pointer or
673  // pointer to member type and E is a pointer or pointer to member type
674  // that can be converted to T by one or more of
675  // -- a qualification conversion
676  // -- a function pointer conversion
677  bool LifetimeConv;
679  // FIXME: Should we treat the exception as catchable if a lifetime
680  // conversion is required?
681  if (IsQualificationConversion(ExceptionType, HandlerType, false,
682  LifetimeConv) ||
683  IsFunctionConversion(ExceptionType, HandlerType, Result))
684  return true;
685 
686  // -- a standard pointer conversion [...]
687  if (!ExceptionType->isPointerType() || !HandlerType->isPointerType())
688  return false;
689 
690  // Handle the "qualification conversion" portion.
691  Qualifiers EQuals, HQuals;
692  ExceptionType = Context.getUnqualifiedArrayType(
693  ExceptionType->getPointeeType(), EQuals);
694  HandlerType = Context.getUnqualifiedArrayType(
695  HandlerType->getPointeeType(), HQuals);
696  if (!HQuals.compatiblyIncludes(EQuals))
697  return false;
698 
699  if (HandlerType->isVoidType() && ExceptionType->isObjectType())
700  return true;
701 
702  // The only remaining case is a derived-to-base conversion.
703  }
704 
705  // -- the handler is of type cg T or cv T& and T is an unambiguous public
706  // base class of E
707  if (!ExceptionType->isRecordType() || !HandlerType->isRecordType())
708  return false;
709  CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/true,
710  /*DetectVirtual=*/false);
711  if (!IsDerivedFrom(SourceLocation(), ExceptionType, HandlerType, Paths) ||
712  Paths.isAmbiguous(Context.getCanonicalType(HandlerType)))
713  return false;
714 
715  // Do this check from a context without privileges.
716  switch (CheckBaseClassAccess(SourceLocation(), HandlerType, ExceptionType,
717  Paths.front(),
718  /*Diagnostic*/ 0,
719  /*ForceCheck*/ true,
720  /*ForceUnprivileged*/ true)) {
721  case AR_accessible: return true;
722  case AR_inaccessible: return false;
723  case AR_dependent:
724  llvm_unreachable("access check dependent for unprivileged context");
725  case AR_delayed:
726  llvm_unreachable("access check delayed in non-declaration");
727  }
728  llvm_unreachable("unexpected access check result");
729 }
730 
731 /// CheckExceptionSpecSubset - Check whether the second function type's
732 /// exception specification is a subset (or equivalent) of the first function
733 /// type. This is used by override and pointer assignment checks.
735  const PartialDiagnostic &NestedDiagID,
736  const PartialDiagnostic &NoteID,
737  const FunctionProtoType *Superset,
738  SourceLocation SuperLoc,
739  const FunctionProtoType *Subset,
740  SourceLocation SubLoc) {
741 
742  // Just auto-succeed under -fno-exceptions.
743  if (!getLangOpts().CXXExceptions)
744  return false;
745 
746  // FIXME: As usual, we could be more specific in our error messages, but
747  // that better waits until we've got types with source locations.
748 
749  if (!SubLoc.isValid())
750  SubLoc = SuperLoc;
751 
752  // Resolve the exception specifications, if needed.
753  Superset = ResolveExceptionSpec(SuperLoc, Superset);
754  if (!Superset)
755  return false;
756  Subset = ResolveExceptionSpec(SubLoc, Subset);
757  if (!Subset)
758  return false;
759 
760  ExceptionSpecificationType SuperEST = Superset->getExceptionSpecType();
762  assert(!isUnresolvedExceptionSpec(SuperEST) &&
763  !isUnresolvedExceptionSpec(SubEST) &&
764  "Shouldn't see unknown exception specifications here");
765 
766  // If there are dependent noexcept specs, assume everything is fine. Unlike
767  // with the equivalency check, this is safe in this case, because we don't
768  // want to merge declarations. Checks after instantiation will catch any
769  // omissions we make here.
770  if (SuperEST == EST_DependentNoexcept || SubEST == EST_DependentNoexcept)
771  return false;
772 
773  CanThrowResult SuperCanThrow = Superset->canThrow();
774  CanThrowResult SubCanThrow = Subset->canThrow();
775 
776  // If the superset contains everything or the subset contains nothing, we're
777  // done.
778  if ((SuperCanThrow == CT_Can && SuperEST != EST_Dynamic) ||
779  SubCanThrow == CT_Cannot)
780  return CheckParamExceptionSpec(NestedDiagID, NoteID, Superset, SuperLoc,
781  Subset, SubLoc);
782 
783  // If the subset contains everything or the superset contains nothing, we've
784  // failed.
785  if ((SubCanThrow == CT_Can && SubEST != EST_Dynamic) ||
786  SuperCanThrow == CT_Cannot) {
787  Diag(SubLoc, DiagID);
788  if (NoteID.getDiagID() != 0)
789  Diag(SuperLoc, NoteID);
790  return true;
791  }
792 
793  assert(SuperEST == EST_Dynamic && SubEST == EST_Dynamic &&
794  "Exception spec subset: non-dynamic case slipped through.");
795 
796  // Neither contains everything or nothing. Do a proper comparison.
797  for (QualType SubI : Subset->exceptions()) {
798  if (const ReferenceType *RefTy = SubI->getAs<ReferenceType>())
799  SubI = RefTy->getPointeeType();
800 
801  // Make sure it's in the superset.
802  bool Contained = false;
803  for (QualType SuperI : Superset->exceptions()) {
804  // [except.spec]p5:
805  // the target entity shall allow at least the exceptions allowed by the
806  // source
807  //
808  // We interpret this as meaning that a handler for some target type would
809  // catch an exception of each source type.
810  if (handlerCanCatch(SuperI, SubI)) {
811  Contained = true;
812  break;
813  }
814  }
815  if (!Contained) {
816  Diag(SubLoc, DiagID);
817  if (NoteID.getDiagID() != 0)
818  Diag(SuperLoc, NoteID);
819  return true;
820  }
821  }
822  // We've run half the gauntlet.
823  return CheckParamExceptionSpec(NestedDiagID, NoteID, Superset, SuperLoc,
824  Subset, SubLoc);
825 }
826 
827 static bool
829  const PartialDiagnostic &NoteID, QualType Target,
830  SourceLocation TargetLoc, QualType Source,
831  SourceLocation SourceLoc) {
832  const FunctionProtoType *TFunc = GetUnderlyingFunction(Target);
833  if (!TFunc)
834  return false;
835  const FunctionProtoType *SFunc = GetUnderlyingFunction(Source);
836  if (!SFunc)
837  return false;
838 
839  return S.CheckEquivalentExceptionSpec(DiagID, NoteID, TFunc, TargetLoc,
840  SFunc, SourceLoc);
841 }
842 
843 /// CheckParamExceptionSpec - Check if the parameter and return types of the
844 /// two functions have equivalent exception specs. This is part of the
845 /// assignment and override compatibility check. We do not check the parameters
846 /// of parameter function pointers recursively, as no sane programmer would
847 /// even be able to write such a function type.
849  const PartialDiagnostic &NoteID,
850  const FunctionProtoType *Target,
851  SourceLocation TargetLoc,
852  const FunctionProtoType *Source,
853  SourceLocation SourceLoc) {
854  auto RetDiag = DiagID;
855  RetDiag << 0;
857  *this, RetDiag, PDiag(),
858  Target->getReturnType(), TargetLoc, Source->getReturnType(),
859  SourceLoc))
860  return true;
861 
862  // We shouldn't even be testing this unless the arguments are otherwise
863  // compatible.
864  assert(Target->getNumParams() == Source->getNumParams() &&
865  "Functions have different argument counts.");
866  for (unsigned i = 0, E = Target->getNumParams(); i != E; ++i) {
867  auto ParamDiag = DiagID;
868  ParamDiag << 1;
870  *this, ParamDiag, PDiag(),
871  Target->getParamType(i), TargetLoc, Source->getParamType(i),
872  SourceLoc))
873  return true;
874  }
875  return false;
876 }
877 
879  // First we check for applicability.
880  // Target type must be a function, function pointer or function reference.
881  const FunctionProtoType *ToFunc = GetUnderlyingFunction(ToType);
882  if (!ToFunc || ToFunc->hasDependentExceptionSpec())
883  return false;
884 
885  // SourceType must be a function or function pointer.
886  const FunctionProtoType *FromFunc = GetUnderlyingFunction(From->getType());
887  if (!FromFunc || FromFunc->hasDependentExceptionSpec())
888  return false;
889 
890  unsigned DiagID = diag::err_incompatible_exception_specs;
891  unsigned NestedDiagID = diag::err_deep_exception_specs_differ;
892  // This is not an error in C++17 onwards, unless the noexceptness doesn't
893  // match, but in that case we have a full-on type mismatch, not just a
894  // type sugar mismatch.
895  if (getLangOpts().CPlusPlus17) {
896  DiagID = diag::warn_incompatible_exception_specs;
897  NestedDiagID = diag::warn_deep_exception_specs_differ;
898  }
899 
900  // Now we've got the correct types on both sides, check their compatibility.
901  // This means that the source of the conversion can only throw a subset of
902  // the exceptions of the target, and any exception specs on arguments or
903  // return types must be equivalent.
904  //
905  // FIXME: If there is a nested dependent exception specification, we should
906  // not be checking it here. This is fine:
907  // template<typename T> void f() {
908  // void (*p)(void (*) throw(T));
909  // void (*q)(void (*) throw(int)) = p;
910  // }
911  // ... because it might be instantiated with T=int.
912  return CheckExceptionSpecSubset(PDiag(DiagID), PDiag(NestedDiagID), PDiag(),
913  ToFunc, From->getSourceRange().getBegin(),
914  FromFunc, SourceLocation()) &&
915  !getLangOpts().CPlusPlus17;
916 }
917 
919  const CXXMethodDecl *Old) {
920  // If the new exception specification hasn't been parsed yet, skip the check.
921  // We'll get called again once it's been parsed.
922  if (New->getType()->castAs<FunctionProtoType>()->getExceptionSpecType() ==
923  EST_Unparsed)
924  return false;
925 
926  // Don't check uninstantiated template destructors at all. We can only
927  // synthesize correct specs after the template is instantiated.
928  if (isa<CXXDestructorDecl>(New) && New->getParent()->isDependentType())
929  return false;
930 
931  // If the old exception specification hasn't been parsed yet, or the new
932  // exception specification can't be computed yet, remember that we need to
933  // perform this check when we get to the end of the outermost
934  // lexically-surrounding class.
936  DelayedOverridingExceptionSpecChecks.push_back({New, Old});
937  return false;
938  }
939 
940  unsigned DiagID = diag::err_override_exception_spec;
941  if (getLangOpts().MicrosoftExt)
942  DiagID = diag::ext_override_exception_spec;
943  return CheckExceptionSpecSubset(PDiag(DiagID),
944  PDiag(diag::err_deep_exception_specs_differ),
945  PDiag(diag::note_overridden_virtual_function),
946  Old->getType()->getAs<FunctionProtoType>(),
947  Old->getLocation(),
948  New->getType()->getAs<FunctionProtoType>(),
949  New->getLocation());
950 }
951 
952 static CanThrowResult canSubExprsThrow(Sema &S, const Expr *E) {
954  for (const Stmt *SubStmt : E->children()) {
955  R = mergeCanThrow(R, S.canThrow(cast<Expr>(SubStmt)));
956  if (R == CT_Can)
957  break;
958  }
959  return R;
960 }
961 
962 static CanThrowResult canCalleeThrow(Sema &S, const Expr *E, const Decl *D) {
963  // As an extension, we assume that __attribute__((nothrow)) functions don't
964  // throw.
965  if (D && isa<FunctionDecl>(D) && D->hasAttr<NoThrowAttr>())
966  return CT_Cannot;
967 
968  QualType T;
969 
970  // In C++1z, just look at the function type of the callee.
971  if (S.getLangOpts().CPlusPlus17 && isa<CallExpr>(E)) {
972  E = cast<CallExpr>(E)->getCallee();
973  T = E->getType();
974  if (T->isSpecificPlaceholderType(BuiltinType::BoundMember)) {
975  // Sadly we don't preserve the actual type as part of the "bound member"
976  // placeholder, so we need to reconstruct it.
977  E = E->IgnoreParenImpCasts();
978 
979  // Could be a call to a pointer-to-member or a plain member access.
980  if (auto *Op = dyn_cast<BinaryOperator>(E)) {
981  assert(Op->getOpcode() == BO_PtrMemD || Op->getOpcode() == BO_PtrMemI);
982  T = Op->getRHS()->getType()
983  ->castAs<MemberPointerType>()->getPointeeType();
984  } else {
985  T = cast<MemberExpr>(E)->getMemberDecl()->getType();
986  }
987  }
988  } else if (const ValueDecl *VD = dyn_cast_or_null<ValueDecl>(D))
989  T = VD->getType();
990  else
991  // If we have no clue what we're calling, assume the worst.
992  return CT_Can;
993 
994  const FunctionProtoType *FT;
995  if ((FT = T->getAs<FunctionProtoType>())) {
996  } else if (const PointerType *PT = T->getAs<PointerType>())
997  FT = PT->getPointeeType()->getAs<FunctionProtoType>();
998  else if (const ReferenceType *RT = T->getAs<ReferenceType>())
999  FT = RT->getPointeeType()->getAs<FunctionProtoType>();
1000  else if (const MemberPointerType *MT = T->getAs<MemberPointerType>())
1001  FT = MT->getPointeeType()->getAs<FunctionProtoType>();
1002  else if (const BlockPointerType *BT = T->getAs<BlockPointerType>())
1003  FT = BT->getPointeeType()->getAs<FunctionProtoType>();
1004 
1005  if (!FT)
1006  return CT_Can;
1007 
1008  FT = S.ResolveExceptionSpec(E->getBeginLoc(), FT);
1009  if (!FT)
1010  return CT_Can;
1011 
1012  return FT->canThrow();
1013 }
1014 
1016  if (DC->isTypeDependent())
1017  return CT_Dependent;
1018 
1019  if (!DC->getTypeAsWritten()->isReferenceType())
1020  return CT_Cannot;
1021 
1022  if (DC->getSubExpr()->isTypeDependent())
1023  return CT_Dependent;
1024 
1025  return DC->getCastKind() == clang::CK_Dynamic? CT_Can : CT_Cannot;
1026 }
1027 
1029  if (DC->isTypeOperand())
1030  return CT_Cannot;
1031 
1032  Expr *Op = DC->getExprOperand();
1033  if (Op->isTypeDependent())
1034  return CT_Dependent;
1035 
1036  const RecordType *RT = Op->getType()->getAs<RecordType>();
1037  if (!RT)
1038  return CT_Cannot;
1039 
1040  if (!cast<CXXRecordDecl>(RT->getDecl())->isPolymorphic())
1041  return CT_Cannot;
1042 
1043  if (Op->Classify(S.Context).isPRValue())
1044  return CT_Cannot;
1045 
1046  return CT_Can;
1047 }
1048 
1050  // C++ [expr.unary.noexcept]p3:
1051  // [Can throw] if in a potentially-evaluated context the expression would
1052  // contain:
1053  switch (E->getStmtClass()) {
1054  case Expr::ConstantExprClass:
1055  return canThrow(cast<ConstantExpr>(E)->getSubExpr());
1056 
1057  case Expr::CXXThrowExprClass:
1058  // - a potentially evaluated throw-expression
1059  return CT_Can;
1060 
1061  case Expr::CXXDynamicCastExprClass: {
1062  // - a potentially evaluated dynamic_cast expression dynamic_cast<T>(v),
1063  // where T is a reference type, that requires a run-time check
1064  CanThrowResult CT = canDynamicCastThrow(cast<CXXDynamicCastExpr>(E));
1065  if (CT == CT_Can)
1066  return CT;
1067  return mergeCanThrow(CT, canSubExprsThrow(*this, E));
1068  }
1069 
1070  case Expr::CXXTypeidExprClass:
1071  // - a potentially evaluated typeid expression applied to a glvalue
1072  // expression whose type is a polymorphic class type
1073  return canTypeidThrow(*this, cast<CXXTypeidExpr>(E));
1074 
1075  // - a potentially evaluated call to a function, member function, function
1076  // pointer, or member function pointer that does not have a non-throwing
1077  // exception-specification
1078  case Expr::CallExprClass:
1079  case Expr::CXXMemberCallExprClass:
1080  case Expr::CXXOperatorCallExprClass:
1081  case Expr::UserDefinedLiteralClass: {
1082  const CallExpr *CE = cast<CallExpr>(E);
1083  CanThrowResult CT;
1084  if (E->isTypeDependent())
1085  CT = CT_Dependent;
1086  else if (isa<CXXPseudoDestructorExpr>(CE->getCallee()->IgnoreParens()))
1087  CT = CT_Cannot;
1088  else
1089  CT = canCalleeThrow(*this, E, CE->getCalleeDecl());
1090  if (CT == CT_Can)
1091  return CT;
1092  return mergeCanThrow(CT, canSubExprsThrow(*this, E));
1093  }
1094 
1095  case Expr::CXXConstructExprClass:
1096  case Expr::CXXTemporaryObjectExprClass: {
1097  CanThrowResult CT = canCalleeThrow(*this, E,
1098  cast<CXXConstructExpr>(E)->getConstructor());
1099  if (CT == CT_Can)
1100  return CT;
1101  return mergeCanThrow(CT, canSubExprsThrow(*this, E));
1102  }
1103 
1104  case Expr::CXXInheritedCtorInitExprClass:
1105  return canCalleeThrow(*this, E,
1106  cast<CXXInheritedCtorInitExpr>(E)->getConstructor());
1107 
1108  case Expr::LambdaExprClass: {
1109  const LambdaExpr *Lambda = cast<LambdaExpr>(E);
1112  Cap = Lambda->capture_init_begin(),
1113  CapEnd = Lambda->capture_init_end();
1114  Cap != CapEnd; ++Cap)
1115  CT = mergeCanThrow(CT, canThrow(*Cap));
1116  return CT;
1117  }
1118 
1119  case Expr::CXXNewExprClass: {
1120  CanThrowResult CT;
1121  if (E->isTypeDependent())
1122  CT = CT_Dependent;
1123  else
1124  CT = canCalleeThrow(*this, E, cast<CXXNewExpr>(E)->getOperatorNew());
1125  if (CT == CT_Can)
1126  return CT;
1127  return mergeCanThrow(CT, canSubExprsThrow(*this, E));
1128  }
1129 
1130  case Expr::CXXDeleteExprClass: {
1131  CanThrowResult CT;
1132  QualType DTy = cast<CXXDeleteExpr>(E)->getDestroyedType();
1133  if (DTy.isNull() || DTy->isDependentType()) {
1134  CT = CT_Dependent;
1135  } else {
1136  CT = canCalleeThrow(*this, E,
1137  cast<CXXDeleteExpr>(E)->getOperatorDelete());
1138  if (const RecordType *RT = DTy->getAs<RecordType>()) {
1139  const CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
1140  const CXXDestructorDecl *DD = RD->getDestructor();
1141  if (DD)
1142  CT = mergeCanThrow(CT, canCalleeThrow(*this, E, DD));
1143  }
1144  if (CT == CT_Can)
1145  return CT;
1146  }
1147  return mergeCanThrow(CT, canSubExprsThrow(*this, E));
1148  }
1149 
1150  case Expr::CXXBindTemporaryExprClass: {
1151  // The bound temporary has to be destroyed again, which might throw.
1152  CanThrowResult CT = canCalleeThrow(*this, E,
1153  cast<CXXBindTemporaryExpr>(E)->getTemporary()->getDestructor());
1154  if (CT == CT_Can)
1155  return CT;
1156  return mergeCanThrow(CT, canSubExprsThrow(*this, E));
1157  }
1158 
1159  // ObjC message sends are like function calls, but never have exception
1160  // specs.
1161  case Expr::ObjCMessageExprClass:
1162  case Expr::ObjCPropertyRefExprClass:
1163  case Expr::ObjCSubscriptRefExprClass:
1164  return CT_Can;
1165 
1166  // All the ObjC literals that are implemented as calls are
1167  // potentially throwing unless we decide to close off that
1168  // possibility.
1169  case Expr::ObjCArrayLiteralClass:
1170  case Expr::ObjCDictionaryLiteralClass:
1171  case Expr::ObjCBoxedExprClass:
1172  return CT_Can;
1173 
1174  // Many other things have subexpressions, so we have to test those.
1175  // Some are simple:
1176  case Expr::CoawaitExprClass:
1177  case Expr::ConditionalOperatorClass:
1178  case Expr::CompoundLiteralExprClass:
1179  case Expr::CoyieldExprClass:
1180  case Expr::CXXConstCastExprClass:
1181  case Expr::CXXReinterpretCastExprClass:
1182  case Expr::CXXStdInitializerListExprClass:
1183  case Expr::DesignatedInitExprClass:
1184  case Expr::DesignatedInitUpdateExprClass:
1185  case Expr::ExprWithCleanupsClass:
1186  case Expr::ExtVectorElementExprClass:
1187  case Expr::InitListExprClass:
1188  case Expr::ArrayInitLoopExprClass:
1189  case Expr::MemberExprClass:
1190  case Expr::ObjCIsaExprClass:
1191  case Expr::ObjCIvarRefExprClass:
1192  case Expr::ParenExprClass:
1193  case Expr::ParenListExprClass:
1194  case Expr::ShuffleVectorExprClass:
1195  case Expr::ConvertVectorExprClass:
1196  case Expr::VAArgExprClass:
1197  return canSubExprsThrow(*this, E);
1198 
1199  // Some might be dependent for other reasons.
1200  case Expr::ArraySubscriptExprClass:
1201  case Expr::OMPArraySectionExprClass:
1202  case Expr::BinaryOperatorClass:
1203  case Expr::DependentCoawaitExprClass:
1204  case Expr::CompoundAssignOperatorClass:
1205  case Expr::CStyleCastExprClass:
1206  case Expr::CXXStaticCastExprClass:
1207  case Expr::CXXFunctionalCastExprClass:
1208  case Expr::ImplicitCastExprClass:
1209  case Expr::MaterializeTemporaryExprClass:
1210  case Expr::UnaryOperatorClass: {
1212  return mergeCanThrow(CT, canSubExprsThrow(*this, E));
1213  }
1214 
1215  // FIXME: We should handle StmtExpr, but that opens a MASSIVE can of worms.
1216  case Expr::StmtExprClass:
1217  return CT_Can;
1218 
1219  case Expr::CXXDefaultArgExprClass:
1220  return canThrow(cast<CXXDefaultArgExpr>(E)->getExpr());
1221 
1222  case Expr::CXXDefaultInitExprClass:
1223  return canThrow(cast<CXXDefaultInitExpr>(E)->getExpr());
1224 
1225  case Expr::ChooseExprClass:
1226  if (E->isTypeDependent() || E->isValueDependent())
1227  return CT_Dependent;
1228  return canThrow(cast<ChooseExpr>(E)->getChosenSubExpr());
1229 
1230  case Expr::GenericSelectionExprClass:
1231  if (cast<GenericSelectionExpr>(E)->isResultDependent())
1232  return CT_Dependent;
1233  return canThrow(cast<GenericSelectionExpr>(E)->getResultExpr());
1234 
1235  // Some expressions are always dependent.
1236  case Expr::CXXDependentScopeMemberExprClass:
1237  case Expr::CXXUnresolvedConstructExprClass:
1238  case Expr::DependentScopeDeclRefExprClass:
1239  case Expr::CXXFoldExprClass:
1240  return CT_Dependent;
1241 
1242  case Expr::AsTypeExprClass:
1243  case Expr::BinaryConditionalOperatorClass:
1244  case Expr::BlockExprClass:
1245  case Expr::CUDAKernelCallExprClass:
1246  case Expr::DeclRefExprClass:
1247  case Expr::ObjCBridgedCastExprClass:
1248  case Expr::ObjCIndirectCopyRestoreExprClass:
1249  case Expr::ObjCProtocolExprClass:
1250  case Expr::ObjCSelectorExprClass:
1251  case Expr::ObjCAvailabilityCheckExprClass:
1252  case Expr::OffsetOfExprClass:
1253  case Expr::PackExpansionExprClass:
1254  case Expr::PseudoObjectExprClass:
1255  case Expr::SubstNonTypeTemplateParmExprClass:
1256  case Expr::SubstNonTypeTemplateParmPackExprClass:
1257  case Expr::FunctionParmPackExprClass:
1258  case Expr::UnaryExprOrTypeTraitExprClass:
1259  case Expr::UnresolvedLookupExprClass:
1260  case Expr::UnresolvedMemberExprClass:
1261  case Expr::TypoExprClass:
1262  // FIXME: Can any of the above throw? If so, when?
1263  return CT_Cannot;
1264 
1265  case Expr::AddrLabelExprClass:
1266  case Expr::ArrayTypeTraitExprClass:
1267  case Expr::AtomicExprClass:
1268  case Expr::TypeTraitExprClass:
1269  case Expr::CXXBoolLiteralExprClass:
1270  case Expr::CXXNoexceptExprClass:
1271  case Expr::CXXNullPtrLiteralExprClass:
1272  case Expr::CXXPseudoDestructorExprClass:
1273  case Expr::CXXScalarValueInitExprClass:
1274  case Expr::CXXThisExprClass:
1275  case Expr::CXXUuidofExprClass:
1276  case Expr::CharacterLiteralClass:
1277  case Expr::ExpressionTraitExprClass:
1278  case Expr::FloatingLiteralClass:
1279  case Expr::GNUNullExprClass:
1280  case Expr::ImaginaryLiteralClass:
1281  case Expr::ImplicitValueInitExprClass:
1282  case Expr::IntegerLiteralClass:
1283  case Expr::FixedPointLiteralClass:
1284  case Expr::ArrayInitIndexExprClass:
1285  case Expr::NoInitExprClass:
1286  case Expr::ObjCEncodeExprClass:
1287  case Expr::ObjCStringLiteralClass:
1288  case Expr::ObjCBoolLiteralExprClass:
1289  case Expr::OpaqueValueExprClass:
1290  case Expr::PredefinedExprClass:
1291  case Expr::SizeOfPackExprClass:
1292  case Expr::StringLiteralClass:
1293  // These expressions can never throw.
1294  return CT_Cannot;
1295 
1296  case Expr::MSPropertyRefExprClass:
1297  case Expr::MSPropertySubscriptExprClass:
1298  llvm_unreachable("Invalid class for expression");
1299 
1300 #define STMT(CLASS, PARENT) case Expr::CLASS##Class:
1301 #define STMT_RANGE(Base, First, Last)
1302 #define LAST_STMT_RANGE(BASE, FIRST, LAST)
1303 #define EXPR(CLASS, PARENT)
1304 #define ABSTRACT_STMT(STMT)
1305 #include "clang/AST/StmtNodes.inc"
1306  case Expr::NoStmtClass:
1307  llvm_unreachable("Invalid class for expression");
1308  }
1309  llvm_unreachable("Bogus StmtClass");
1310 }
1311 
1312 } // end namespace clang
CanThrowResult canThrow(const Expr *E)
Represents a function declaration or definition.
Definition: Decl.h:1739
no exception specification
PointerType - C99 6.7.5.1 - Pointer Declarators.
Definition: Type.h:2543
A (possibly-)qualified type.
Definition: Type.h:642
bool isArrayType() const
Definition: Type.h:6331
bool isMemberPointerType() const
Definition: Type.h:6313
bool CheckExceptionSpecCompatibility(Expr *From, QualType ToType)
void UpdateExceptionSpec(FunctionDecl *FD, const FunctionProtoType::ExceptionSpecInfo &ESI)
unsigned getNumExceptions() const
Return the number of types in the exception specification.
Definition: Type.h:3939
bool isExternC() const
Determines whether this function is a function with external, C linkage.
Definition: Decl.cpp:2902
void InstantiateExceptionSpec(SourceLocation PointOfInstantiation, FunctionDecl *Function)
const FunctionProtoType * ResolveExceptionSpec(SourceLocation Loc, const FunctionProtoType *FPT)
Stmt - This represents one statement.
Definition: Stmt.h:66
ExprResult ActOnNoexceptSpec(SourceLocation NoexceptLoc, Expr *NoexceptExpr, ExceptionSpecificationType &EST)
Check the given noexcept-specifier, convert its expression, and compute the appropriate ExceptionSpec...
QualType getPointeeType() const
If this is a pointer, ObjC object pointer, or block pointer, this returns the respective pointee...
Definition: Type.cpp:505
Defines the SourceManager interface.
SmallVector< std::pair< const CXXMethodDecl *, const CXXMethodDecl * >, 2 > DelayedOverridingExceptionSpecChecks
All the overriding functions seen during a class definition that had their exception spec checks dela...
Definition: Sema.h:619
bool isRecordType() const
Definition: Type.h:6355
bool isSpecificPlaceholderType(unsigned K) const
Test for a specific placeholder type.
Definition: Type.h:6517
SemaDiagnosticBuilder Diag(SourceLocation Loc, unsigned DiagID)
Emit a diagnostic.
Definition: Sema.h:1302
Decl - This represents one declaration (or definition), e.g.
Definition: DeclBase.h:87
bool CheckParamExceptionSpec(const PartialDiagnostic &NestedDiagID, const PartialDiagnostic &NoteID, const FunctionProtoType *Target, SourceLocation TargetLoc, const FunctionProtoType *Source, SourceLocation SourceLoc)
CheckParamExceptionSpec - Check if the parameter and return types of the two functions have equivalen...
Classification Classify(ASTContext &Ctx) const
Classify - Classify this expression according to the C++11 expression taxonomy.
Definition: Expr.h:377
OverloadedOperatorKind getCXXOverloadedOperator() const
If this name is the name of an overloadable operator in C++ (e.g., operator+), retrieve the kind of o...
void EvaluateImplicitExceptionSpec(SourceLocation Loc, CXXMethodDecl *MD)
Evaluate the implicit exception specification for a defaulted special member function.
CanQual< T > getUnqualifiedType() const
Retrieve the unqualified form of this type.
SourceLocation getBeginLoc() const LLVM_READONLY
Definition: DeclSpec.h:1873
Represent a C++ namespace.
Definition: Decl.h:514
SourceLocation getLocForEndOfToken(SourceLocation Loc, unsigned Offset=0)
Calls Lexer::getLocForEndOfToken()
Definition: Sema.cpp:46
A container of type source information.
Definition: Decl.h:86
PartialDiagnostic PDiag(unsigned DiagID=0)
Build a partial diagnostic.
Definition: SemaInternal.h:25
Information about one declarator, including the parsed type information and the identifier.
Definition: DeclSpec.h:1748
unsigned getNumParams() const
Definition: Type.h:3879
const T * getAs() const
Member-template getAs<specific type>&#39;.
Definition: Type.h:6716
PrintingPolicy getPrintingPolicy() const
Retrieve a suitable printing policy for diagnostics.
Definition: Sema.h:2171
void Profile(llvm::FoldingSetNodeID &ID, const ASTContext &Context, bool Canonical) const
Produce a unique representation of the given statement.
Expr * getExprOperand() const
Definition: ExprCXX.h:721
Defines the clang::Expr interface and subclasses for C++ expressions.
noexcept(expression), value-dependent
The collection of all-type qualifiers we support.
Definition: Type.h:141
Base wrapper for a particular "section" of type source info.
Definition: TypeLoc.h:57
DeclarationName getDeclName() const
Get the actual, stored name of the declaration, which may be a special name.
Definition: Decl.h:297
One of these records is kept for each identifier that is lexed.
SmallVector< std::pair< FunctionDecl *, FunctionDecl * >, 2 > DelayedEquivalentExceptionSpecChecks
All the function redeclarations seen during a class definition that had their exception spec checks d...
Definition: Sema.h:627
bool isStr(const char(&Str)[StrLen]) const
Return true if this is the identifier for the specified string.
ArrayRef< QualType > getParamTypes() const
Definition: Type.h:3886
bool IsDerivedFrom(SourceLocation Loc, QualType Derived, QualType Base)
Determine whether the type Derived is a C++ class that is derived from the type Base.
SourceLocation getBeginLoc() const LLVM_READONLY
Definition: Stmt.cpp:288
bool isReferenceType() const
Definition: Type.h:6294
Expr * getSubExpr()
Definition: Expr.h:2982
bool isReplaceableGlobalAllocationFunction(bool *IsAligned=nullptr) const
Determines whether this function is one of the replaceable global allocation functions: void *operato...
Definition: Decl.cpp:2818
A C++ typeid expression (C++ [expr.typeid]), which gets the type_info that corresponds to the supplie...
Definition: ExprCXX.h:664
PtrTy get() const
Definition: Ownership.h:174
bool CheckOverridingFunctionExceptionSpec(const CXXMethodDecl *New, const CXXMethodDecl *Old)
CheckOverridingFunctionExceptionSpec - Checks whether the exception spec is a subset of base spec...
capture_init_iterator capture_init_begin()
Retrieve the first initialization argument for this lambda expression (which initializes the first ca...
Definition: ExprCXX.h:1751
child_range children()
Definition: Stmt.cpp:237
bool IsFunctionConversion(QualType FromType, QualType ToType, QualType &ResultTy)
Determine whether the conversion from FromType to ToType is a valid conversion that strips "noexcept"...
bool isVolatileQualified() const
Determine whether this type is volatile-qualified.
Definition: Type.h:6128
static bool CheckSpecForTypesEquivalent(Sema &S, const PartialDiagnostic &DiagID, const PartialDiagnostic &NoteID, QualType Target, SourceLocation TargetLoc, QualType Source, SourceLocation SourceLoc)
Defines the Diagnostic-related interfaces.
static bool CheckEquivalentExceptionSpecImpl(Sema &S, const PartialDiagnostic &DiagID, const PartialDiagnostic &NoteID, const FunctionProtoType *Old, SourceLocation OldLoc, const FunctionProtoType *New, SourceLocation NewLoc, bool *MissingExceptionSpecification=nullptr, bool *MissingEmptyExceptionSpecification=nullptr, bool AllowNoexceptAllMatchWithNoSpec=false, bool IsOperatorNew=false)
CheckEquivalentExceptionSpec - Check if the two types have compatible exception specifications.
A C++ lambda expression, which produces a function object (of unspecified type) that can be invoked l...
Definition: ExprCXX.h:1606
const LangOptions & getLangOpts() const
Definition: Sema.h:1225
bool isTypeDependent() const
isTypeDependent - Determines whether this expression is type-dependent (C++ [temp.dep.expr]), which means that its type could change from one template instantiation to the next.
Definition: Expr.h:167
CXXDestructorDecl * getDestructor() const
Returns the destructor decl for this class.
Definition: DeclCXX.cpp:1697
IdentifierInfo * getIdentifier() const
Definition: DeclSpec.h:2110
QualType getTypeAsWritten() const
getTypeAsWritten - Returns the type that this expression is casting to, as written in the source code...
Definition: Expr.h:3154
bool hasAttr() const
Definition: DeclBase.h:531
Sema - This implements semantic analysis and AST building for C.
Definition: Sema.h:278
CXXRecordDecl * getAsCXXRecordDecl() const
Retrieves the CXXRecordDecl that this type refers to, either because the type is a RecordType or beca...
Definition: Type.cpp:1613
FunctionDecl * getExceptionSpecDecl() const
If this function type has an exception specification which hasn&#39;t been determined yet (either because...
Definition: Type.h:3964
Represents a prototype with parameter type info, e.g.
Definition: Type.h:3686
bool compatiblyIncludes(Qualifiers other) const
Determines if these qualifiers compatibly include another set.
Definition: Type.h:486
CanThrowResult mergeCanThrow(CanThrowResult CT1, CanThrowResult CT2)
bool isDependentType() const
Whether this declaration declares a type that is dependent, i.e., a type that somehow depends on temp...
Definition: Decl.h:3229
Represent the declaration of a variable (in which case it is an lvalue) a function (in which case it ...
Definition: Decl.h:636
This represents one expression.
Definition: Expr.h:106
QualType getPointeeType() const
Definition: Type.h:2700
bool isInSystemHeader(SourceLocation Loc) const
Returns if a SourceLocation is in a system header.
const T * castAs() const
Member-template castAs<specific type>.
Definition: Type.h:6779
T getAs() const
Convert to the specified TypeLoc type, returning a null TypeLoc if this TypeLoc is not of the desired...
Definition: TypeLoc.h:87
Represents a C++ destructor within a class.
Definition: DeclCXX.h:2703
void setInvalidDecl(bool Invalid=true)
setInvalidDecl - Indicates the Decl had a semantic error.
Definition: DeclBase.cpp:132
const Expr * getCallee() const
Definition: Expr.h:2451
bool isNullPtrType() const
Definition: Type.h:6555
ExprResult VerifyIntegerConstantExpression(Expr *E, llvm::APSInt *Result, VerifyICEDiagnoser &Diagnoser, bool AllowFold=true)
VerifyIntegerConstantExpression - Verifies that an expression is an ICE, and reports the appropriate ...
Definition: SemaExpr.cpp:14227
bool RequireCompleteType(SourceLocation Loc, QualType T, TypeDiagnoser &Diagnoser)
Ensure that the type T is a complete type.
Definition: SemaType.cpp:7586
Defines the clang::TypeLoc interface and its subclasses.
QualType getType() const
Definition: Expr.h:128
bool handlerCanCatch(QualType HandlerType, QualType ExceptionType)
bool isInvalid() const
Definition: Ownership.h:170
QualType getFunctionType(QualType ResultTy, ArrayRef< QualType > Args, const FunctionProtoType::ExtProtoInfo &EPI) const
Return a normal function type with a typed argument list.
Definition: ASTContext.h:1379
The result type of a method or function.
bool isNull() const
Return true if this QualType doesn&#39;t point to a type yet.
Definition: Type.h:707
static CanThrowResult canDynamicCastThrow(const CXXDynamicCastExpr *DC)
bool isConstQualified() const
Determine whether this type is const-qualified.
Definition: Type.h:6117
RecordDecl * getDecl() const
Definition: Type.h:4366
noexcept(expression), evals to &#39;false&#39;
CanThrowResult
Possible results from evaluation of a noexcept expression.
A C++ dynamic_cast expression (C++ [expr.dynamic.cast]).
Definition: ExprCXX.h:348
Kind
ActionResult - This structure is used while parsing/acting on expressions, stmts, etc...
Definition: Ownership.h:157
ExceptionSpecificationType Type
The kind of exception specification this is.
Definition: Type.h:3738
TypeLoc IgnoreParens() const
Definition: TypeLoc.h:1127
ExtProtoInfo getExtProtoInfo() const
Definition: Type.h:3890
redecl_range redecls() const
Returns an iterator range for all the redeclarations of the same decl.
Definition: Redeclarable.h:295
Encodes a location in the source.
QualType getReturnType() const
Definition: Type.h:3617
bool CheckDistantExceptionSpec(QualType T)
CheckDistantExceptionSpec - Check if the given type is a pointer or pointer to member to a function w...
CastKind getCastKind() const
Definition: Expr.h:2976
Represents a static or instance method of a struct/union/class.
Definition: DeclCXX.h:2041
bool hasExceptionSpec() const
Return whether this function has any kind of exception spec.
Definition: Type.h:3919
static bool hasImplicitExceptionSpec(FunctionDecl *Decl)
Determine whether a function has an implicitly-generated exception specification. ...
bool isStdNamespace() const
Definition: DeclBase.cpp:1062
static CanThrowResult canTypeidThrow(Sema &S, const CXXTypeidExpr *DC)
Represents a canonical, potentially-qualified type.
Definition: CanonicalType.h:66
Expr * getNoexceptExpr() const
Return the expression inside noexcept(expression), or a null pointer if there is none (because the ex...
Definition: Type.h:3954
bool isValueDependent() const
isValueDependent - Determines whether this expression is value-dependent (C++ [temp.dep.constexpr]).
Definition: Expr.h:149
bool isLibstdcxxEagerExceptionSpecHack(const Declarator &D)
Determine if we&#39;re in a case where we need to (incorrectly) eagerly parse an exception specification ...
bool hasSameUnqualifiedType(QualType T1, QualType T2) const
Determine whether the given types are equivalent after cvr-qualifiers have been removed.
Definition: ASTContext.h:2292
ExceptionSpecificationType getExceptionSpecType() const
Get the kind of exception specification on this function.
Definition: Type.h:3913
QualType getArrayDecayedType(QualType T) const
Return the properly qualified result of decaying the specified array type to a pointer.
exception_iterator exception_begin() const
Definition: Type.h:4034
StringRef getName() const
Return the actual identifier string.
bool isTypeOperand() const
Definition: ExprCXX.h:704
Dataflow Directional Tag Classes.
bool isValid() const
Return true if this is a valid SourceLocation object.
not evaluated yet, for special member function
OverloadedOperatorKind
Enumeration specifying the different kinds of C++ overloaded operators.
Definition: OperatorKinds.h:22
ASTMutationListener * getASTMutationListener() const
Definition: Sema.cpp:398
bool hasDependentExceptionSpec() const
Return whether this function has a dependent exception spec.
Definition: Type.cpp:2955
StmtClass getStmtClass() const
Definition: Stmt.h:809
ArrayRef< QualType > exceptions() const
Definition: Type.h:4030
const CXXRecordDecl * getParent() const
Returns the parent of this method declaration, which is the class in which this method is defined...
Definition: DeclCXX.h:2166
bool isAmbiguous(CanQualType BaseType)
Determine whether the path from the most-derived type to the given base type is ambiguous (i...
A pointer to member type per C++ 8.3.3 - Pointers to members.
Definition: Type.h:2762
ExtProtoInfo withExceptionSpec(const ExceptionSpecInfo &ESI)
Definition: Type.h:3776
Expr * IgnoreParenImpCasts() LLVM_READONLY
IgnoreParenImpCasts - Ignore parentheses and implicit casts.
Definition: Expr.cpp:2652
Decl * getCalleeDecl()
Definition: Expr.cpp:1287
Pointer to a block type.
Definition: Type.h:2645
A helper class that allows the use of isa/cast/dyncast to detect TagType objects of structs/unions/cl...
Definition: Type.h:4356
CanThrowResult canThrow() const
Determine whether this function type has a non-throwing exception specification.
Definition: Type.cpp:2976
bool CheckExceptionSpecSubset(const PartialDiagnostic &DiagID, const PartialDiagnostic &NestedDiagID, const PartialDiagnostic &NoteID, const FunctionProtoType *Superset, SourceLocation SuperLoc, const FunctionProtoType *Subset, SourceLocation SubLoc)
CheckExceptionSpecSubset - Check whether the second function type&#39;s exception specification is a subs...
bool isFunctionType() const
Definition: Type.h:6278
TypeSourceInfo * getTypeSourceInfo() const
Definition: Decl.h:715
CXXBasePath & front()
Base for LValueReferenceType and RValueReferenceType.
Definition: Type.h:2679
ExceptionSpecificationType
The various types of exception specifications that exist in C++11.
Holds information about the various types of exception specification.
Definition: Type.h:3736
static FixItHint CreateInsertion(SourceLocation InsertionLoc, StringRef Code, bool BeforePreviousInsertions=false)
Create a code modification hint that inserts the given code string at a specific location.
Definition: Diagnostic.h:92
bool isObjectType() const
Determine whether this type is an object type.
Definition: Type.h:1872
SourceManager & getSourceManager()
Definition: ASTContext.h:661
CanQualType getCanonicalType(QualType T) const
Return the canonical (structural) type corresponding to the specified potentially non-canonical type ...
Definition: ASTContext.h:2252
QualType getParamType(unsigned i) const
Definition: Type.h:3881
void printPretty(raw_ostream &OS, PrinterHelper *Helper, const PrintingPolicy &Policy, unsigned Indentation=0, StringRef NewlineSymbol="\, const ASTContext *Context=nullptr) const
Represents a C++ struct/union/class.
Definition: DeclCXX.h:300
bool isVoidType() const
Definition: Type.h:6530
unsigned getBuiltinID() const
Returns a value indicating whether this function corresponds to a builtin function.
Definition: Decl.cpp:2994
bool CheckSpecifiedExceptionType(QualType &T, SourceRange Range)
CheckSpecifiedExceptionType - Check if the given type is valid in an exception specification.
bool isPRValue() const
Definition: Expr.h:355
AccessResult CheckBaseClassAccess(SourceLocation AccessLoc, QualType Base, QualType Derived, const CXXBasePath &Path, unsigned DiagID, bool ForceCheck=false, bool ForceUnprivileged=false)
Checks access for a hierarchy conversion.
DeclContext * CurContext
CurContext - This is the current declaration context of parsing.
Definition: Sema.h:332
QualType getPointerType(QualType T) const
Return the uniqued reference to the type for a pointer to the specified type.
SourceRange getSourceRange() const LLVM_READONLY
SourceLocation tokens are not useful in isolation - they are low level value objects created/interpre...
Definition: Stmt.cpp:276
CallExpr - Represents a function call (C99 6.5.2.2, C++ [expr.call]).
Definition: Expr.h:2407
void adjustExceptionSpec(FunctionDecl *FD, const FunctionProtoType::ExceptionSpecInfo &ESI, bool AsWritten=false)
Change the exception specification on a function once it is delay-parsed, instantiated, or computed.
static CanThrowResult canCalleeThrow(Sema &S, const Expr *E, const Decl *D)
bool IsQualificationConversion(QualType FromType, QualType ToType, bool CStyle, bool &ObjCLifetimeConversion)
IsQualificationConversion - Determines whether the conversion from an rvalue of type FromType to ToTy...
bool isDependentType() const
Whether this type is a dependent type, meaning that its definition somehow depends on a template para...
Definition: Type.h:2085
capture_init_iterator capture_init_end()
Retrieve the iterator pointing one past the last initialization argument for this lambda expression...
Definition: ExprCXX.h:1763
Expr *const * const_capture_init_iterator
Const iterator that walks over the capture initialization arguments.
Definition: ExprCXX.h:1737
bool isPointerType() const
Definition: Type.h:6282
BasePaths - Represents the set of paths from a derived class to one of its (direct or indirect) bases...
static bool exceptionSpecNotKnownYet(const FunctionDecl *FD)
QualType getType() const
Definition: Decl.h:647
bool isUnresolvedExceptionSpec(ExceptionSpecificationType ESpecType)
A trivial tuple used to represent a source range.
ASTContext & Context
Definition: Sema.h:320
ExprResult CheckBooleanCondition(SourceLocation Loc, Expr *E, bool IsConstexpr=false)
CheckBooleanCondition - Diagnose problems involving the use of the given expression as a boolean cond...
Definition: SemaExpr.cpp:16104
static CanThrowResult canSubExprsThrow(Sema &S, const Expr *E)
bool CheckEquivalentExceptionSpec(FunctionDecl *Old, FunctionDecl *New)
void setType(QualType newType)
Definition: Decl.h:648
SourceLocation getBegin() const
static const FunctionProtoType * GetUnderlyingFunction(QualType T)
QualType getUnqualifiedArrayType(QualType T, Qualifiers &Quals)
Return this type as a completely-unqualified array type, capturing the qualifiers in Quals...
SourceLocation getLocation() const
Definition: DeclBase.h:418
QualType getType() const
Return the type wrapped by this type source info.
Definition: Decl.h:97
noexcept(expression), evals to &#39;true&#39;
Expr * IgnoreParens() LLVM_READONLY
IgnoreParens - Ignore parentheses.
Definition: Expr.cpp:2523