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SemaDeclCXX.cpp
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1 //===------ SemaDeclCXX.cpp - Semantic Analysis for C++ Declarations ------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file implements semantic analysis for C++ declarations.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "clang/AST/ASTConsumer.h"
14 #include "clang/AST/ASTContext.h"
15 #include "clang/AST/ASTLambda.h"
18 #include "clang/AST/CharUnits.h"
21 #include "clang/AST/ExprCXX.h"
22 #include "clang/AST/RecordLayout.h"
24 #include "clang/AST/StmtVisitor.h"
25 #include "clang/AST/TypeLoc.h"
26 #include "clang/AST/TypeOrdering.h"
29 #include "clang/Basic/TargetInfo.h"
31 #include "clang/Lex/Preprocessor.h"
33 #include "clang/Sema/DeclSpec.h"
35 #include "clang/Sema/Lookup.h"
37 #include "clang/Sema/Scope.h"
38 #include "clang/Sema/ScopeInfo.h"
40 #include "clang/Sema/Template.h"
41 #include "llvm/ADT/STLExtras.h"
42 #include "llvm/ADT/SmallString.h"
43 #include "llvm/ADT/StringExtras.h"
44 #include <map>
45 #include <set>
46 
47 using namespace clang;
48 
49 //===----------------------------------------------------------------------===//
50 // CheckDefaultArgumentVisitor
51 //===----------------------------------------------------------------------===//
52 
53 namespace {
54  /// CheckDefaultArgumentVisitor - C++ [dcl.fct.default] Traverses
55  /// the default argument of a parameter to determine whether it
56  /// contains any ill-formed subexpressions. For example, this will
57  /// diagnose the use of local variables or parameters within the
58  /// default argument expression.
59  class CheckDefaultArgumentVisitor
60  : public StmtVisitor<CheckDefaultArgumentVisitor, bool> {
61  Expr *DefaultArg;
62  Sema *S;
63 
64  public:
65  CheckDefaultArgumentVisitor(Expr *defarg, Sema *s)
66  : DefaultArg(defarg), S(s) {}
67 
68  bool VisitExpr(Expr *Node);
69  bool VisitDeclRefExpr(DeclRefExpr *DRE);
70  bool VisitCXXThisExpr(CXXThisExpr *ThisE);
71  bool VisitLambdaExpr(LambdaExpr *Lambda);
72  bool VisitPseudoObjectExpr(PseudoObjectExpr *POE);
73  };
74 
75  /// VisitExpr - Visit all of the children of this expression.
76  bool CheckDefaultArgumentVisitor::VisitExpr(Expr *Node) {
77  bool IsInvalid = false;
78  for (Stmt *SubStmt : Node->children())
79  IsInvalid |= Visit(SubStmt);
80  return IsInvalid;
81  }
82 
83  /// VisitDeclRefExpr - Visit a reference to a declaration, to
84  /// determine whether this declaration can be used in the default
85  /// argument expression.
86  bool CheckDefaultArgumentVisitor::VisitDeclRefExpr(DeclRefExpr *DRE) {
87  NamedDecl *Decl = DRE->getDecl();
88  if (ParmVarDecl *Param = dyn_cast<ParmVarDecl>(Decl)) {
89  // C++ [dcl.fct.default]p9
90  // Default arguments are evaluated each time the function is
91  // called. The order of evaluation of function arguments is
92  // unspecified. Consequently, parameters of a function shall not
93  // be used in default argument expressions, even if they are not
94  // evaluated. Parameters of a function declared before a default
95  // argument expression are in scope and can hide namespace and
96  // class member names.
97  return S->Diag(DRE->getBeginLoc(),
98  diag::err_param_default_argument_references_param)
99  << Param->getDeclName() << DefaultArg->getSourceRange();
100  } else if (VarDecl *VDecl = dyn_cast<VarDecl>(Decl)) {
101  // C++ [dcl.fct.default]p7
102  // Local variables shall not be used in default argument
103  // expressions.
104  if (VDecl->isLocalVarDecl())
105  return S->Diag(DRE->getBeginLoc(),
106  diag::err_param_default_argument_references_local)
107  << VDecl->getDeclName() << DefaultArg->getSourceRange();
108  }
109 
110  return false;
111  }
112 
113  /// VisitCXXThisExpr - Visit a C++ "this" expression.
114  bool CheckDefaultArgumentVisitor::VisitCXXThisExpr(CXXThisExpr *ThisE) {
115  // C++ [dcl.fct.default]p8:
116  // The keyword this shall not be used in a default argument of a
117  // member function.
118  return S->Diag(ThisE->getBeginLoc(),
119  diag::err_param_default_argument_references_this)
120  << ThisE->getSourceRange();
121  }
122 
123  bool CheckDefaultArgumentVisitor::VisitPseudoObjectExpr(PseudoObjectExpr *POE) {
124  bool Invalid = false;
126  i = POE->semantics_begin(), e = POE->semantics_end(); i != e; ++i) {
127  Expr *E = *i;
128 
129  // Look through bindings.
130  if (OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(E)) {
131  E = OVE->getSourceExpr();
132  assert(E && "pseudo-object binding without source expression?");
133  }
134 
135  Invalid |= Visit(E);
136  }
137  return Invalid;
138  }
139 
140  bool CheckDefaultArgumentVisitor::VisitLambdaExpr(LambdaExpr *Lambda) {
141  // C++11 [expr.lambda.prim]p13:
142  // A lambda-expression appearing in a default argument shall not
143  // implicitly or explicitly capture any entity.
144  if (Lambda->capture_begin() == Lambda->capture_end())
145  return false;
146 
147  return S->Diag(Lambda->getBeginLoc(), diag::err_lambda_capture_default_arg);
148  }
149 }
150 
151 void
153  const CXXMethodDecl *Method) {
154  // If we have an MSAny spec already, don't bother.
155  if (!Method || ComputedEST == EST_MSAny)
156  return;
157 
158  const FunctionProtoType *Proto
159  = Method->getType()->getAs<FunctionProtoType>();
160  Proto = Self->ResolveExceptionSpec(CallLoc, Proto);
161  if (!Proto)
162  return;
163 
165 
166  // If we have a throw-all spec at this point, ignore the function.
167  if (ComputedEST == EST_None)
168  return;
169 
170  if (EST == EST_None && Method->hasAttr<NoThrowAttr>())
171  EST = EST_BasicNoexcept;
172 
173  switch (EST) {
174  case EST_Unparsed:
175  case EST_Uninstantiated:
176  case EST_Unevaluated:
177  llvm_unreachable("should not see unresolved exception specs here");
178 
179  // If this function can throw any exceptions, make a note of that.
180  case EST_MSAny:
181  case EST_None:
182  // FIXME: Whichever we see last of MSAny and None determines our result.
183  // We should make a consistent, order-independent choice here.
184  ClearExceptions();
185  ComputedEST = EST;
186  return;
187  case EST_NoexceptFalse:
188  ClearExceptions();
189  ComputedEST = EST_None;
190  return;
191  // FIXME: If the call to this decl is using any of its default arguments, we
192  // need to search them for potentially-throwing calls.
193  // If this function has a basic noexcept, it doesn't affect the outcome.
194  case EST_BasicNoexcept:
195  case EST_NoexceptTrue:
196  case EST_NoThrow:
197  return;
198  // If we're still at noexcept(true) and there's a throw() callee,
199  // change to that specification.
200  case EST_DynamicNone:
201  if (ComputedEST == EST_BasicNoexcept)
202  ComputedEST = EST_DynamicNone;
203  return;
205  llvm_unreachable(
206  "should not generate implicit declarations for dependent cases");
207  case EST_Dynamic:
208  break;
209  }
210  assert(EST == EST_Dynamic && "EST case not considered earlier.");
211  assert(ComputedEST != EST_None &&
212  "Shouldn't collect exceptions when throw-all is guaranteed.");
213  ComputedEST = EST_Dynamic;
214  // Record the exceptions in this function's exception specification.
215  for (const auto &E : Proto->exceptions())
216  if (ExceptionsSeen.insert(Self->Context.getCanonicalType(E)).second)
217  Exceptions.push_back(E);
218 }
219 
221  if (!E || ComputedEST == EST_MSAny)
222  return;
223 
224  // FIXME:
225  //
226  // C++0x [except.spec]p14:
227  // [An] implicit exception-specification specifies the type-id T if and
228  // only if T is allowed by the exception-specification of a function directly
229  // invoked by f's implicit definition; f shall allow all exceptions if any
230  // function it directly invokes allows all exceptions, and f shall allow no
231  // exceptions if every function it directly invokes allows no exceptions.
232  //
233  // Note in particular that if an implicit exception-specification is generated
234  // for a function containing a throw-expression, that specification can still
235  // be noexcept(true).
236  //
237  // Note also that 'directly invoked' is not defined in the standard, and there
238  // is no indication that we should only consider potentially-evaluated calls.
239  //
240  // Ultimately we should implement the intent of the standard: the exception
241  // specification should be the set of exceptions which can be thrown by the
242  // implicit definition. For now, we assume that any non-nothrow expression can
243  // throw any exception.
244 
245  if (Self->canThrow(E))
246  ComputedEST = EST_None;
247 }
248 
249 bool
251  SourceLocation EqualLoc) {
252  if (RequireCompleteType(Param->getLocation(), Param->getType(),
253  diag::err_typecheck_decl_incomplete_type)) {
254  Param->setInvalidDecl();
255  return true;
256  }
257 
258  // C++ [dcl.fct.default]p5
259  // A default argument expression is implicitly converted (clause
260  // 4) to the parameter type. The default argument expression has
261  // the same semantic constraints as the initializer expression in
262  // a declaration of a variable of the parameter type, using the
263  // copy-initialization semantics (8.5).
265  Param);
267  EqualLoc);
268  InitializationSequence InitSeq(*this, Entity, Kind, Arg);
269  ExprResult Result = InitSeq.Perform(*this, Entity, Kind, Arg);
270  if (Result.isInvalid())
271  return true;
272  Arg = Result.getAs<Expr>();
273 
274  CheckCompletedExpr(Arg, EqualLoc);
275  Arg = MaybeCreateExprWithCleanups(Arg);
276 
277  // Okay: add the default argument to the parameter
278  Param->setDefaultArg(Arg);
279 
280  // We have already instantiated this parameter; provide each of the
281  // instantiations with the uninstantiated default argument.
282  UnparsedDefaultArgInstantiationsMap::iterator InstPos
283  = UnparsedDefaultArgInstantiations.find(Param);
284  if (InstPos != UnparsedDefaultArgInstantiations.end()) {
285  for (unsigned I = 0, N = InstPos->second.size(); I != N; ++I)
286  InstPos->second[I]->setUninstantiatedDefaultArg(Arg);
287 
288  // We're done tracking this parameter's instantiations.
289  UnparsedDefaultArgInstantiations.erase(InstPos);
290  }
291 
292  return false;
293 }
294 
295 /// ActOnParamDefaultArgument - Check whether the default argument
296 /// provided for a function parameter is well-formed. If so, attach it
297 /// to the parameter declaration.
298 void
300  Expr *DefaultArg) {
301  if (!param || !DefaultArg)
302  return;
303 
304  ParmVarDecl *Param = cast<ParmVarDecl>(param);
305  UnparsedDefaultArgLocs.erase(Param);
306 
307  // Default arguments are only permitted in C++
308  if (!getLangOpts().CPlusPlus) {
309  Diag(EqualLoc, diag::err_param_default_argument)
310  << DefaultArg->getSourceRange();
311  Param->setInvalidDecl();
312  return;
313  }
314 
315  // Check for unexpanded parameter packs.
316  if (DiagnoseUnexpandedParameterPack(DefaultArg, UPPC_DefaultArgument)) {
317  Param->setInvalidDecl();
318  return;
319  }
320 
321  // C++11 [dcl.fct.default]p3
322  // A default argument expression [...] shall not be specified for a
323  // parameter pack.
324  if (Param->isParameterPack()) {
325  Diag(EqualLoc, diag::err_param_default_argument_on_parameter_pack)
326  << DefaultArg->getSourceRange();
327  return;
328  }
329 
330  // Check that the default argument is well-formed
331  CheckDefaultArgumentVisitor DefaultArgChecker(DefaultArg, this);
332  if (DefaultArgChecker.Visit(DefaultArg)) {
333  Param->setInvalidDecl();
334  return;
335  }
336 
337  SetParamDefaultArgument(Param, DefaultArg, EqualLoc);
338 }
339 
340 /// ActOnParamUnparsedDefaultArgument - We've seen a default
341 /// argument for a function parameter, but we can't parse it yet
342 /// because we're inside a class definition. Note that this default
343 /// argument will be parsed later.
345  SourceLocation EqualLoc,
346  SourceLocation ArgLoc) {
347  if (!param)
348  return;
349 
350  ParmVarDecl *Param = cast<ParmVarDecl>(param);
351  Param->setUnparsedDefaultArg();
352  UnparsedDefaultArgLocs[Param] = ArgLoc;
353 }
354 
355 /// ActOnParamDefaultArgumentError - Parsing or semantic analysis of
356 /// the default argument for the parameter param failed.
358  SourceLocation EqualLoc) {
359  if (!param)
360  return;
361 
362  ParmVarDecl *Param = cast<ParmVarDecl>(param);
363  Param->setInvalidDecl();
364  UnparsedDefaultArgLocs.erase(Param);
365  Param->setDefaultArg(new(Context)
366  OpaqueValueExpr(EqualLoc,
367  Param->getType().getNonReferenceType(),
368  VK_RValue));
369 }
370 
371 /// CheckExtraCXXDefaultArguments - Check for any extra default
372 /// arguments in the declarator, which is not a function declaration
373 /// or definition and therefore is not permitted to have default
374 /// arguments. This routine should be invoked for every declarator
375 /// that is not a function declaration or definition.
377  // C++ [dcl.fct.default]p3
378  // A default argument expression shall be specified only in the
379  // parameter-declaration-clause of a function declaration or in a
380  // template-parameter (14.1). It shall not be specified for a
381  // parameter pack. If it is specified in a
382  // parameter-declaration-clause, it shall not occur within a
383  // declarator or abstract-declarator of a parameter-declaration.
384  bool MightBeFunction = D.isFunctionDeclarationContext();
385  for (unsigned i = 0, e = D.getNumTypeObjects(); i != e; ++i) {
386  DeclaratorChunk &chunk = D.getTypeObject(i);
387  if (chunk.Kind == DeclaratorChunk::Function) {
388  if (MightBeFunction) {
389  // This is a function declaration. It can have default arguments, but
390  // keep looking in case its return type is a function type with default
391  // arguments.
392  MightBeFunction = false;
393  continue;
394  }
395  for (unsigned argIdx = 0, e = chunk.Fun.NumParams; argIdx != e;
396  ++argIdx) {
397  ParmVarDecl *Param = cast<ParmVarDecl>(chunk.Fun.Params[argIdx].Param);
398  if (Param->hasUnparsedDefaultArg()) {
399  std::unique_ptr<CachedTokens> Toks =
400  std::move(chunk.Fun.Params[argIdx].DefaultArgTokens);
401  SourceRange SR;
402  if (Toks->size() > 1)
403  SR = SourceRange((*Toks)[1].getLocation(),
404  Toks->back().getLocation());
405  else
406  SR = UnparsedDefaultArgLocs[Param];
407  Diag(Param->getLocation(), diag::err_param_default_argument_nonfunc)
408  << SR;
409  } else if (Param->getDefaultArg()) {
410  Diag(Param->getLocation(), diag::err_param_default_argument_nonfunc)
411  << Param->getDefaultArg()->getSourceRange();
412  Param->setDefaultArg(nullptr);
413  }
414  }
415  } else if (chunk.Kind != DeclaratorChunk::Paren) {
416  MightBeFunction = false;
417  }
418  }
419 }
420 
422  for (unsigned NumParams = FD->getNumParams(); NumParams > 0; --NumParams) {
423  const ParmVarDecl *PVD = FD->getParamDecl(NumParams-1);
424  if (!PVD->hasDefaultArg())
425  return false;
426  if (!PVD->hasInheritedDefaultArg())
427  return true;
428  }
429  return false;
430 }
431 
432 /// MergeCXXFunctionDecl - Merge two declarations of the same C++
433 /// function, once we already know that they have the same
434 /// type. Subroutine of MergeFunctionDecl. Returns true if there was an
435 /// error, false otherwise.
437  Scope *S) {
438  bool Invalid = false;
439 
440  // The declaration context corresponding to the scope is the semantic
441  // parent, unless this is a local function declaration, in which case
442  // it is that surrounding function.
443  DeclContext *ScopeDC = New->isLocalExternDecl()
444  ? New->getLexicalDeclContext()
445  : New->getDeclContext();
446 
447  // Find the previous declaration for the purpose of default arguments.
448  FunctionDecl *PrevForDefaultArgs = Old;
449  for (/**/; PrevForDefaultArgs;
450  // Don't bother looking back past the latest decl if this is a local
451  // extern declaration; nothing else could work.
452  PrevForDefaultArgs = New->isLocalExternDecl()
453  ? nullptr
454  : PrevForDefaultArgs->getPreviousDecl()) {
455  // Ignore hidden declarations.
456  if (!LookupResult::isVisible(*this, PrevForDefaultArgs))
457  continue;
458 
459  if (S && !isDeclInScope(PrevForDefaultArgs, ScopeDC, S) &&
460  !New->isCXXClassMember()) {
461  // Ignore default arguments of old decl if they are not in
462  // the same scope and this is not an out-of-line definition of
463  // a member function.
464  continue;
465  }
466 
467  if (PrevForDefaultArgs->isLocalExternDecl() != New->isLocalExternDecl()) {
468  // If only one of these is a local function declaration, then they are
469  // declared in different scopes, even though isDeclInScope may think
470  // they're in the same scope. (If both are local, the scope check is
471  // sufficient, and if neither is local, then they are in the same scope.)
472  continue;
473  }
474 
475  // We found the right previous declaration.
476  break;
477  }
478 
479  // C++ [dcl.fct.default]p4:
480  // For non-template functions, default arguments can be added in
481  // later declarations of a function in the same
482  // scope. Declarations in different scopes have completely
483  // distinct sets of default arguments. That is, declarations in
484  // inner scopes do not acquire default arguments from
485  // declarations in outer scopes, and vice versa. In a given
486  // function declaration, all parameters subsequent to a
487  // parameter with a default argument shall have default
488  // arguments supplied in this or previous declarations. A
489  // default argument shall not be redefined by a later
490  // declaration (not even to the same value).
491  //
492  // C++ [dcl.fct.default]p6:
493  // Except for member functions of class templates, the default arguments
494  // in a member function definition that appears outside of the class
495  // definition are added to the set of default arguments provided by the
496  // member function declaration in the class definition.
497  for (unsigned p = 0, NumParams = PrevForDefaultArgs
498  ? PrevForDefaultArgs->getNumParams()
499  : 0;
500  p < NumParams; ++p) {
501  ParmVarDecl *OldParam = PrevForDefaultArgs->getParamDecl(p);
502  ParmVarDecl *NewParam = New->getParamDecl(p);
503 
504  bool OldParamHasDfl = OldParam ? OldParam->hasDefaultArg() : false;
505  bool NewParamHasDfl = NewParam->hasDefaultArg();
506 
507  if (OldParamHasDfl && NewParamHasDfl) {
508  unsigned DiagDefaultParamID =
509  diag::err_param_default_argument_redefinition;
510 
511  // MSVC accepts that default parameters be redefined for member functions
512  // of template class. The new default parameter's value is ignored.
513  Invalid = true;
514  if (getLangOpts().MicrosoftExt) {
515  CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(New);
516  if (MD && MD->getParent()->getDescribedClassTemplate()) {
517  // Merge the old default argument into the new parameter.
518  NewParam->setHasInheritedDefaultArg();
519  if (OldParam->hasUninstantiatedDefaultArg())
520  NewParam->setUninstantiatedDefaultArg(
521  OldParam->getUninstantiatedDefaultArg());
522  else
523  NewParam->setDefaultArg(OldParam->getInit());
524  DiagDefaultParamID = diag::ext_param_default_argument_redefinition;
525  Invalid = false;
526  }
527  }
528 
529  // FIXME: If we knew where the '=' was, we could easily provide a fix-it
530  // hint here. Alternatively, we could walk the type-source information
531  // for NewParam to find the last source location in the type... but it
532  // isn't worth the effort right now. This is the kind of test case that
533  // is hard to get right:
534  // int f(int);
535  // void g(int (*fp)(int) = f);
536  // void g(int (*fp)(int) = &f);
537  Diag(NewParam->getLocation(), DiagDefaultParamID)
538  << NewParam->getDefaultArgRange();
539 
540  // Look for the function declaration where the default argument was
541  // actually written, which may be a declaration prior to Old.
542  for (auto Older = PrevForDefaultArgs;
543  OldParam->hasInheritedDefaultArg(); /**/) {
544  Older = Older->getPreviousDecl();
545  OldParam = Older->getParamDecl(p);
546  }
547 
548  Diag(OldParam->getLocation(), diag::note_previous_definition)
549  << OldParam->getDefaultArgRange();
550  } else if (OldParamHasDfl) {
551  // Merge the old default argument into the new parameter unless the new
552  // function is a friend declaration in a template class. In the latter
553  // case the default arguments will be inherited when the friend
554  // declaration will be instantiated.
555  if (New->getFriendObjectKind() == Decl::FOK_None ||
557  // It's important to use getInit() here; getDefaultArg()
558  // strips off any top-level ExprWithCleanups.
559  NewParam->setHasInheritedDefaultArg();
560  if (OldParam->hasUnparsedDefaultArg())
561  NewParam->setUnparsedDefaultArg();
562  else if (OldParam->hasUninstantiatedDefaultArg())
563  NewParam->setUninstantiatedDefaultArg(
564  OldParam->getUninstantiatedDefaultArg());
565  else
566  NewParam->setDefaultArg(OldParam->getInit());
567  }
568  } else if (NewParamHasDfl) {
569  if (New->getDescribedFunctionTemplate()) {
570  // Paragraph 4, quoted above, only applies to non-template functions.
571  Diag(NewParam->getLocation(),
572  diag::err_param_default_argument_template_redecl)
573  << NewParam->getDefaultArgRange();
574  Diag(PrevForDefaultArgs->getLocation(),
575  diag::note_template_prev_declaration)
576  << false;
577  } else if (New->getTemplateSpecializationKind()
580  // C++ [temp.expr.spec]p21:
581  // Default function arguments shall not be specified in a declaration
582  // or a definition for one of the following explicit specializations:
583  // - the explicit specialization of a function template;
584  // - the explicit specialization of a member function template;
585  // - the explicit specialization of a member function of a class
586  // template where the class template specialization to which the
587  // member function specialization belongs is implicitly
588  // instantiated.
589  Diag(NewParam->getLocation(), diag::err_template_spec_default_arg)
591  << New->getDeclName()
592  << NewParam->getDefaultArgRange();
593  } else if (New->getDeclContext()->isDependentContext()) {
594  // C++ [dcl.fct.default]p6 (DR217):
595  // Default arguments for a member function of a class template shall
596  // be specified on the initial declaration of the member function
597  // within the class template.
598  //
599  // Reading the tea leaves a bit in DR217 and its reference to DR205
600  // leads me to the conclusion that one cannot add default function
601  // arguments for an out-of-line definition of a member function of a
602  // dependent type.
603  int WhichKind = 2;
604  if (CXXRecordDecl *Record
605  = dyn_cast<CXXRecordDecl>(New->getDeclContext())) {
606  if (Record->getDescribedClassTemplate())
607  WhichKind = 0;
608  else if (isa<ClassTemplatePartialSpecializationDecl>(Record))
609  WhichKind = 1;
610  else
611  WhichKind = 2;
612  }
613 
614  Diag(NewParam->getLocation(),
615  diag::err_param_default_argument_member_template_redecl)
616  << WhichKind
617  << NewParam->getDefaultArgRange();
618  }
619  }
620  }
621 
622  // DR1344: If a default argument is added outside a class definition and that
623  // default argument makes the function a special member function, the program
624  // is ill-formed. This can only happen for constructors.
625  if (isa<CXXConstructorDecl>(New) &&
627  CXXSpecialMember NewSM = getSpecialMember(cast<CXXMethodDecl>(New)),
628  OldSM = getSpecialMember(cast<CXXMethodDecl>(Old));
629  if (NewSM != OldSM) {
630  ParmVarDecl *NewParam = New->getParamDecl(New->getMinRequiredArguments());
631  assert(NewParam->hasDefaultArg());
632  Diag(NewParam->getLocation(), diag::err_default_arg_makes_ctor_special)
633  << NewParam->getDefaultArgRange() << NewSM;
634  Diag(Old->getLocation(), diag::note_previous_declaration);
635  }
636  }
637 
638  const FunctionDecl *Def;
639  // C++11 [dcl.constexpr]p1: If any declaration of a function or function
640  // template has a constexpr specifier then all its declarations shall
641  // contain the constexpr specifier.
642  if (New->getConstexprKind() != Old->getConstexprKind()) {
643  Diag(New->getLocation(), diag::err_constexpr_redecl_mismatch)
644  << New << New->getConstexprKind() << Old->getConstexprKind();
645  Diag(Old->getLocation(), diag::note_previous_declaration);
646  Invalid = true;
647  } else if (!Old->getMostRecentDecl()->isInlined() && New->isInlined() &&
648  Old->isDefined(Def) &&
649  // If a friend function is inlined but does not have 'inline'
650  // specifier, it is a definition. Do not report attribute conflict
651  // in this case, redefinition will be diagnosed later.
652  (New->isInlineSpecified() ||
653  New->getFriendObjectKind() == Decl::FOK_None)) {
654  // C++11 [dcl.fcn.spec]p4:
655  // If the definition of a function appears in a translation unit before its
656  // first declaration as inline, the program is ill-formed.
657  Diag(New->getLocation(), diag::err_inline_decl_follows_def) << New;
658  Diag(Def->getLocation(), diag::note_previous_definition);
659  Invalid = true;
660  }
661 
662  // C++17 [temp.deduct.guide]p3:
663  // Two deduction guide declarations in the same translation unit
664  // for the same class template shall not have equivalent
665  // parameter-declaration-clauses.
666  if (isa<CXXDeductionGuideDecl>(New) &&
668  Diag(New->getLocation(), diag::err_deduction_guide_redeclared);
669  Diag(Old->getLocation(), diag::note_previous_declaration);
670  }
671 
672  // C++11 [dcl.fct.default]p4: If a friend declaration specifies a default
673  // argument expression, that declaration shall be a definition and shall be
674  // the only declaration of the function or function template in the
675  // translation unit.
678  Diag(New->getLocation(), diag::err_friend_decl_with_def_arg_redeclared);
679  Diag(Old->getLocation(), diag::note_previous_declaration);
680  Invalid = true;
681  }
682 
683  return Invalid;
684 }
685 
686 NamedDecl *
688  MultiTemplateParamsArg TemplateParamLists) {
689  assert(D.isDecompositionDeclarator());
691 
692  // The syntax only allows a decomposition declarator as a simple-declaration,
693  // a for-range-declaration, or a condition in Clang, but we parse it in more
694  // cases than that.
696  Diag(Decomp.getLSquareLoc(), diag::err_decomp_decl_context)
697  << Decomp.getSourceRange();
698  return nullptr;
699  }
700 
701  if (!TemplateParamLists.empty()) {
702  // FIXME: There's no rule against this, but there are also no rules that
703  // would actually make it usable, so we reject it for now.
704  Diag(TemplateParamLists.front()->getTemplateLoc(),
705  diag::err_decomp_decl_template);
706  return nullptr;
707  }
708 
709  Diag(Decomp.getLSquareLoc(),
710  !getLangOpts().CPlusPlus17
711  ? diag::ext_decomp_decl
713  ? diag::ext_decomp_decl_cond
714  : diag::warn_cxx14_compat_decomp_decl)
715  << Decomp.getSourceRange();
716 
717  // The semantic context is always just the current context.
718  DeclContext *const DC = CurContext;
719 
720  // C++17 [dcl.dcl]/8:
721  // The decl-specifier-seq shall contain only the type-specifier auto
722  // and cv-qualifiers.
723  // C++2a [dcl.dcl]/8:
724  // If decl-specifier-seq contains any decl-specifier other than static,
725  // thread_local, auto, or cv-qualifiers, the program is ill-formed.
726  auto &DS = D.getDeclSpec();
727  {
728  SmallVector<StringRef, 8> BadSpecifiers;
729  SmallVector<SourceLocation, 8> BadSpecifierLocs;
730  SmallVector<StringRef, 8> CPlusPlus20Specifiers;
731  SmallVector<SourceLocation, 8> CPlusPlus20SpecifierLocs;
732  if (auto SCS = DS.getStorageClassSpec()) {
733  if (SCS == DeclSpec::SCS_static) {
734  CPlusPlus20Specifiers.push_back(DeclSpec::getSpecifierName(SCS));
735  CPlusPlus20SpecifierLocs.push_back(DS.getStorageClassSpecLoc());
736  } else {
737  BadSpecifiers.push_back(DeclSpec::getSpecifierName(SCS));
738  BadSpecifierLocs.push_back(DS.getStorageClassSpecLoc());
739  }
740  }
741  if (auto TSCS = DS.getThreadStorageClassSpec()) {
742  CPlusPlus20Specifiers.push_back(DeclSpec::getSpecifierName(TSCS));
743  CPlusPlus20SpecifierLocs.push_back(DS.getThreadStorageClassSpecLoc());
744  }
745  if (DS.hasConstexprSpecifier()) {
746  BadSpecifiers.push_back(
747  DeclSpec::getSpecifierName(DS.getConstexprSpecifier()));
748  BadSpecifierLocs.push_back(DS.getConstexprSpecLoc());
749  }
750  if (DS.isInlineSpecified()) {
751  BadSpecifiers.push_back("inline");
752  BadSpecifierLocs.push_back(DS.getInlineSpecLoc());
753  }
754  if (!BadSpecifiers.empty()) {
755  auto &&Err = Diag(BadSpecifierLocs.front(), diag::err_decomp_decl_spec);
756  Err << (int)BadSpecifiers.size()
757  << llvm::join(BadSpecifiers.begin(), BadSpecifiers.end(), " ");
758  // Don't add FixItHints to remove the specifiers; we do still respect
759  // them when building the underlying variable.
760  for (auto Loc : BadSpecifierLocs)
761  Err << SourceRange(Loc, Loc);
762  } else if (!CPlusPlus20Specifiers.empty()) {
763  auto &&Warn = Diag(CPlusPlus20SpecifierLocs.front(),
764  getLangOpts().CPlusPlus2a
765  ? diag::warn_cxx17_compat_decomp_decl_spec
766  : diag::ext_decomp_decl_spec);
767  Warn << (int)CPlusPlus20Specifiers.size()
768  << llvm::join(CPlusPlus20Specifiers.begin(),
769  CPlusPlus20Specifiers.end(), " ");
770  for (auto Loc : CPlusPlus20SpecifierLocs)
771  Warn << SourceRange(Loc, Loc);
772  }
773  // We can't recover from it being declared as a typedef.
774  if (DS.getStorageClassSpec() == DeclSpec::SCS_typedef)
775  return nullptr;
776  }
777 
778  // C++2a [dcl.struct.bind]p1:
779  // A cv that includes volatile is deprecated
780  if ((DS.getTypeQualifiers() & DeclSpec::TQ_volatile) &&
781  getLangOpts().CPlusPlus2a)
782  Diag(DS.getVolatileSpecLoc(),
783  diag::warn_deprecated_volatile_structured_binding);
784 
785  TypeSourceInfo *TInfo = GetTypeForDeclarator(D, S);
786  QualType R = TInfo->getType();
787 
788  if (DiagnoseUnexpandedParameterPack(D.getIdentifierLoc(), TInfo,
789  UPPC_DeclarationType))
790  D.setInvalidType();
791 
792  // The syntax only allows a single ref-qualifier prior to the decomposition
793  // declarator. No other declarator chunks are permitted. Also check the type
794  // specifier here.
795  if (DS.getTypeSpecType() != DeclSpec::TST_auto ||
796  D.hasGroupingParens() || D.getNumTypeObjects() > 1 ||
797  (D.getNumTypeObjects() == 1 &&
799  Diag(Decomp.getLSquareLoc(),
800  (D.hasGroupingParens() ||
801  (D.getNumTypeObjects() &&
803  ? diag::err_decomp_decl_parens
804  : diag::err_decomp_decl_type)
805  << R;
806 
807  // In most cases, there's no actual problem with an explicitly-specified
808  // type, but a function type won't work here, and ActOnVariableDeclarator
809  // shouldn't be called for such a type.
810  if (R->isFunctionType())
811  D.setInvalidType();
812  }
813 
814  // Build the BindingDecls.
816 
817  // Build the BindingDecls.
818  for (auto &B : D.getDecompositionDeclarator().bindings()) {
819  // Check for name conflicts.
820  DeclarationNameInfo NameInfo(B.Name, B.NameLoc);
821  LookupResult Previous(*this, NameInfo, LookupOrdinaryName,
822  ForVisibleRedeclaration);
823  LookupName(Previous, S,
824  /*CreateBuiltins*/DC->getRedeclContext()->isTranslationUnit());
825 
826  // It's not permitted to shadow a template parameter name.
827  if (Previous.isSingleResult() &&
828  Previous.getFoundDecl()->isTemplateParameter()) {
829  DiagnoseTemplateParameterShadow(D.getIdentifierLoc(),
830  Previous.getFoundDecl());
831  Previous.clear();
832  }
833 
834  bool ConsiderLinkage = DC->isFunctionOrMethod() &&
835  DS.getStorageClassSpec() == DeclSpec::SCS_extern;
836  FilterLookupForScope(Previous, DC, S, ConsiderLinkage,
837  /*AllowInlineNamespace*/false);
838  if (!Previous.empty()) {
839  auto *Old = Previous.getRepresentativeDecl();
840  Diag(B.NameLoc, diag::err_redefinition) << B.Name;
841  Diag(Old->getLocation(), diag::note_previous_definition);
842  }
843 
844  auto *BD = BindingDecl::Create(Context, DC, B.NameLoc, B.Name);
845  PushOnScopeChains(BD, S, true);
846  Bindings.push_back(BD);
847  ParsingInitForAutoVars.insert(BD);
848  }
849 
850  // There are no prior lookup results for the variable itself, because it
851  // is unnamed.
852  DeclarationNameInfo NameInfo((IdentifierInfo *)nullptr,
853  Decomp.getLSquareLoc());
854  LookupResult Previous(*this, NameInfo, LookupOrdinaryName,
855  ForVisibleRedeclaration);
856 
857  // Build the variable that holds the non-decomposed object.
858  bool AddToScope = true;
859  NamedDecl *New =
860  ActOnVariableDeclarator(S, D, DC, TInfo, Previous,
861  MultiTemplateParamsArg(), AddToScope, Bindings);
862  if (AddToScope) {
863  S->AddDecl(New);
864  CurContext->addHiddenDecl(New);
865  }
866 
867  if (isInOpenMPDeclareTargetContext())
868  checkDeclIsAllowedInOpenMPTarget(nullptr, New);
869 
870  return New;
871 }
872 
874  Sema &S, ArrayRef<BindingDecl *> Bindings, ValueDecl *Src,
875  QualType DecompType, const llvm::APSInt &NumElems, QualType ElemType,
876  llvm::function_ref<ExprResult(SourceLocation, Expr *, unsigned)> GetInit) {
877  if ((int64_t)Bindings.size() != NumElems) {
878  S.Diag(Src->getLocation(), diag::err_decomp_decl_wrong_number_bindings)
879  << DecompType << (unsigned)Bindings.size() << NumElems.toString(10)
880  << (NumElems < Bindings.size());
881  return true;
882  }
883 
884  unsigned I = 0;
885  for (auto *B : Bindings) {
886  SourceLocation Loc = B->getLocation();
887  ExprResult E = S.BuildDeclRefExpr(Src, DecompType, VK_LValue, Loc);
888  if (E.isInvalid())
889  return true;
890  E = GetInit(Loc, E.get(), I++);
891  if (E.isInvalid())
892  return true;
893  B->setBinding(ElemType, E.get());
894  }
895 
896  return false;
897 }
898 
900  ArrayRef<BindingDecl *> Bindings,
901  ValueDecl *Src, QualType DecompType,
902  const llvm::APSInt &NumElems,
903  QualType ElemType) {
905  S, Bindings, Src, DecompType, NumElems, ElemType,
906  [&](SourceLocation Loc, Expr *Base, unsigned I) -> ExprResult {
907  ExprResult E = S.ActOnIntegerConstant(Loc, I);
908  if (E.isInvalid())
909  return ExprError();
910  return S.CreateBuiltinArraySubscriptExpr(Base, Loc, E.get(), Loc);
911  });
912 }
913 
915  ValueDecl *Src, QualType DecompType,
916  const ConstantArrayType *CAT) {
917  return checkArrayLikeDecomposition(S, Bindings, Src, DecompType,
918  llvm::APSInt(CAT->getSize()),
919  CAT->getElementType());
920 }
921 
923  ValueDecl *Src, QualType DecompType,
924  const VectorType *VT) {
926  S, Bindings, Src, DecompType, llvm::APSInt::get(VT->getNumElements()),
928  DecompType.getQualifiers()));
929 }
930 
932  ArrayRef<BindingDecl *> Bindings,
933  ValueDecl *Src, QualType DecompType,
934  const ComplexType *CT) {
936  S, Bindings, Src, DecompType, llvm::APSInt::get(2),
938  DecompType.getQualifiers()),
939  [&](SourceLocation Loc, Expr *Base, unsigned I) -> ExprResult {
940  return S.CreateBuiltinUnaryOp(Loc, I ? UO_Imag : UO_Real, Base);
941  });
942 }
943 
945  TemplateArgumentListInfo &Args) {
946  SmallString<128> SS;
947  llvm::raw_svector_ostream OS(SS);
948  bool First = true;
949  for (auto &Arg : Args.arguments()) {
950  if (!First)
951  OS << ", ";
952  Arg.getArgument().print(PrintingPolicy, OS);
953  First = false;
954  }
955  return OS.str();
956 }
957 
958 static bool lookupStdTypeTraitMember(Sema &S, LookupResult &TraitMemberLookup,
959  SourceLocation Loc, StringRef Trait,
961  unsigned DiagID) {
962  auto DiagnoseMissing = [&] {
963  if (DiagID)
964  S.Diag(Loc, DiagID) << printTemplateArgs(S.Context.getPrintingPolicy(),
965  Args);
966  return true;
967  };
968 
969  // FIXME: Factor out duplication with lookupPromiseType in SemaCoroutine.
971  if (!Std)
972  return DiagnoseMissing();
973 
974  // Look up the trait itself, within namespace std. We can diagnose various
975  // problems with this lookup even if we've been asked to not diagnose a
976  // missing specialization, because this can only fail if the user has been
977  // declaring their own names in namespace std or we don't support the
978  // standard library implementation in use.
981  if (!S.LookupQualifiedName(Result, Std))
982  return DiagnoseMissing();
983  if (Result.isAmbiguous())
984  return true;
985 
986  ClassTemplateDecl *TraitTD = Result.getAsSingle<ClassTemplateDecl>();
987  if (!TraitTD) {
988  Result.suppressDiagnostics();
989  NamedDecl *Found = *Result.begin();
990  S.Diag(Loc, diag::err_std_type_trait_not_class_template) << Trait;
991  S.Diag(Found->getLocation(), diag::note_declared_at);
992  return true;
993  }
994 
995  // Build the template-id.
996  QualType TraitTy = S.CheckTemplateIdType(TemplateName(TraitTD), Loc, Args);
997  if (TraitTy.isNull())
998  return true;
999  if (!S.isCompleteType(Loc, TraitTy)) {
1000  if (DiagID)
1002  Loc, TraitTy, DiagID,
1004  return true;
1005  }
1006 
1007  CXXRecordDecl *RD = TraitTy->getAsCXXRecordDecl();
1008  assert(RD && "specialization of class template is not a class?");
1009 
1010  // Look up the member of the trait type.
1011  S.LookupQualifiedName(TraitMemberLookup, RD);
1012  return TraitMemberLookup.isAmbiguous();
1013 }
1014 
1015 static TemplateArgumentLoc
1017  uint64_t I) {
1018  TemplateArgument Arg(S.Context, S.Context.MakeIntValue(I, T), T);
1019  return S.getTrivialTemplateArgumentLoc(Arg, T, Loc);
1020 }
1021 
1022 static TemplateArgumentLoc
1025 }
1026 
1027 namespace { enum class IsTupleLike { TupleLike, NotTupleLike, Error }; }
1028 
1030  llvm::APSInt &Size) {
1033 
1035  LookupResult R(S, Value, Loc, Sema::LookupOrdinaryName);
1036 
1037  // Form template argument list for tuple_size<T>.
1038  TemplateArgumentListInfo Args(Loc, Loc);
1040 
1041  // If there's no tuple_size specialization or the lookup of 'value' is empty,
1042  // it's not tuple-like.
1043  if (lookupStdTypeTraitMember(S, R, Loc, "tuple_size", Args, /*DiagID*/ 0) ||
1044  R.empty())
1045  return IsTupleLike::NotTupleLike;
1046 
1047  // If we get this far, we've committed to the tuple interpretation, but
1048  // we can still fail if there actually isn't a usable ::value.
1049 
1050  struct ICEDiagnoser : Sema::VerifyICEDiagnoser {
1051  LookupResult &R;
1053  ICEDiagnoser(LookupResult &R, TemplateArgumentListInfo &Args)
1054  : R(R), Args(Args) {}
1055  void diagnoseNotICE(Sema &S, SourceLocation Loc, SourceRange SR) {
1056  S.Diag(Loc, diag::err_decomp_decl_std_tuple_size_not_constant)
1058  }
1059  } Diagnoser(R, Args);
1060 
1061  ExprResult E =
1062  S.BuildDeclarationNameExpr(CXXScopeSpec(), R, /*NeedsADL*/false);
1063  if (E.isInvalid())
1064  return IsTupleLike::Error;
1065 
1066  E = S.VerifyIntegerConstantExpression(E.get(), &Size, Diagnoser, false);
1067  if (E.isInvalid())
1068  return IsTupleLike::Error;
1069 
1070  return IsTupleLike::TupleLike;
1071 }
1072 
1073 /// \return std::tuple_element<I, T>::type.
1075  unsigned I, QualType T) {
1076  // Form template argument list for tuple_element<I, T>.
1077  TemplateArgumentListInfo Args(Loc, Loc);
1078  Args.addArgument(
1081 
1082  DeclarationName TypeDN = S.PP.getIdentifierInfo("type");
1083  LookupResult R(S, TypeDN, Loc, Sema::LookupOrdinaryName);
1085  S, R, Loc, "tuple_element", Args,
1086  diag::err_decomp_decl_std_tuple_element_not_specialized))
1087  return QualType();
1088 
1089  auto *TD = R.getAsSingle<TypeDecl>();
1090  if (!TD) {
1091  R.suppressDiagnostics();
1092  S.Diag(Loc, diag::err_decomp_decl_std_tuple_element_not_specialized)
1094  if (!R.empty())
1095  S.Diag(R.getRepresentativeDecl()->getLocation(), diag::note_declared_at);
1096  return QualType();
1097  }
1098 
1099  return S.Context.getTypeDeclType(TD);
1100 }
1101 
1102 namespace {
1103 struct BindingDiagnosticTrap {
1104  Sema &S;
1105  DiagnosticErrorTrap Trap;
1106  BindingDecl *BD;
1107 
1108  BindingDiagnosticTrap(Sema &S, BindingDecl *BD)
1109  : S(S), Trap(S.Diags), BD(BD) {}
1110  ~BindingDiagnosticTrap() {
1111  if (Trap.hasErrorOccurred())
1112  S.Diag(BD->getLocation(), diag::note_in_binding_decl_init) << BD;
1113  }
1114 };
1115 }
1116 
1118  ArrayRef<BindingDecl *> Bindings,
1119  VarDecl *Src, QualType DecompType,
1120  const llvm::APSInt &TupleSize) {
1121  if ((int64_t)Bindings.size() != TupleSize) {
1122  S.Diag(Src->getLocation(), diag::err_decomp_decl_wrong_number_bindings)
1123  << DecompType << (unsigned)Bindings.size() << TupleSize.toString(10)
1124  << (TupleSize < Bindings.size());
1125  return true;
1126  }
1127 
1128  if (Bindings.empty())
1129  return false;
1130 
1131  DeclarationName GetDN = S.PP.getIdentifierInfo("get");
1132 
1133  // [dcl.decomp]p3:
1134  // The unqualified-id get is looked up in the scope of E by class member
1135  // access lookup ...
1136  LookupResult MemberGet(S, GetDN, Src->getLocation(), Sema::LookupMemberName);
1137  bool UseMemberGet = false;
1138  if (S.isCompleteType(Src->getLocation(), DecompType)) {
1139  if (auto *RD = DecompType->getAsCXXRecordDecl())
1140  S.LookupQualifiedName(MemberGet, RD);
1141  if (MemberGet.isAmbiguous())
1142  return true;
1143  // ... and if that finds at least one declaration that is a function
1144  // template whose first template parameter is a non-type parameter ...
1145  for (NamedDecl *D : MemberGet) {
1146  if (FunctionTemplateDecl *FTD =
1147  dyn_cast<FunctionTemplateDecl>(D->getUnderlyingDecl())) {
1148  TemplateParameterList *TPL = FTD->getTemplateParameters();
1149  if (TPL->size() != 0 &&
1150  isa<NonTypeTemplateParmDecl>(TPL->getParam(0))) {
1151  // ... the initializer is e.get<i>().
1152  UseMemberGet = true;
1153  break;
1154  }
1155  }
1156  }
1157  }
1158 
1159  unsigned I = 0;
1160  for (auto *B : Bindings) {
1161  BindingDiagnosticTrap Trap(S, B);
1162  SourceLocation Loc = B->getLocation();
1163 
1164  ExprResult E = S.BuildDeclRefExpr(Src, DecompType, VK_LValue, Loc);
1165  if (E.isInvalid())
1166  return true;
1167 
1168  // e is an lvalue if the type of the entity is an lvalue reference and
1169  // an xvalue otherwise
1170  if (!Src->getType()->isLValueReferenceType())
1171  E = ImplicitCastExpr::Create(S.Context, E.get()->getType(), CK_NoOp,
1172  E.get(), nullptr, VK_XValue);
1173 
1174  TemplateArgumentListInfo Args(Loc, Loc);
1175  Args.addArgument(
1177 
1178  if (UseMemberGet) {
1179  // if [lookup of member get] finds at least one declaration, the
1180  // initializer is e.get<i-1>().
1181  E = S.BuildMemberReferenceExpr(E.get(), DecompType, Loc, false,
1182  CXXScopeSpec(), SourceLocation(), nullptr,
1183  MemberGet, &Args, nullptr);
1184  if (E.isInvalid())
1185  return true;
1186 
1187  E = S.BuildCallExpr(nullptr, E.get(), Loc, None, Loc);
1188  } else {
1189  // Otherwise, the initializer is get<i-1>(e), where get is looked up
1190  // in the associated namespaces.
1193  DeclarationNameInfo(GetDN, Loc), /*RequiresADL*/true, &Args,
1195 
1196  Expr *Arg = E.get();
1197  E = S.BuildCallExpr(nullptr, Get, Loc, Arg, Loc);
1198  }
1199  if (E.isInvalid())
1200  return true;
1201  Expr *Init = E.get();
1202 
1203  // Given the type T designated by std::tuple_element<i - 1, E>::type,
1204  QualType T = getTupleLikeElementType(S, Loc, I, DecompType);
1205  if (T.isNull())
1206  return true;
1207 
1208  // each vi is a variable of type "reference to T" initialized with the
1209  // initializer, where the reference is an lvalue reference if the
1210  // initializer is an lvalue and an rvalue reference otherwise
1211  QualType RefType =
1212  S.BuildReferenceType(T, E.get()->isLValue(), Loc, B->getDeclName());
1213  if (RefType.isNull())
1214  return true;
1215  auto *RefVD = VarDecl::Create(
1216  S.Context, Src->getDeclContext(), Loc, Loc,
1217  B->getDeclName().getAsIdentifierInfo(), RefType,
1220  RefVD->setTSCSpec(Src->getTSCSpec());
1221  RefVD->setImplicit();
1222  if (Src->isInlineSpecified())
1223  RefVD->setInlineSpecified();
1224  RefVD->getLexicalDeclContext()->addHiddenDecl(RefVD);
1225 
1228  InitializationSequence Seq(S, Entity, Kind, Init);
1229  E = Seq.Perform(S, Entity, Kind, Init);
1230  if (E.isInvalid())
1231  return true;
1232  E = S.ActOnFinishFullExpr(E.get(), Loc, /*DiscardedValue*/ false);
1233  if (E.isInvalid())
1234  return true;
1235  RefVD->setInit(E.get());
1236  if (!E.get()->isValueDependent())
1237  RefVD->checkInitIsICE();
1238 
1240  DeclarationNameInfo(B->getDeclName(), Loc),
1241  RefVD);
1242  if (E.isInvalid())
1243  return true;
1244 
1245  B->setBinding(T, E.get());
1246  I++;
1247  }
1248 
1249  return false;
1250 }
1251 
1252 /// Find the base class to decompose in a built-in decomposition of a class type.
1253 /// This base class search is, unfortunately, not quite like any other that we
1254 /// perform anywhere else in C++.
1256  const CXXRecordDecl *RD,
1257  CXXCastPath &BasePath) {
1258  auto BaseHasFields = [](const CXXBaseSpecifier *Specifier,
1259  CXXBasePath &Path) {
1260  return Specifier->getType()->getAsCXXRecordDecl()->hasDirectFields();
1261  };
1262 
1263  const CXXRecordDecl *ClassWithFields = nullptr;
1265  if (RD->hasDirectFields())
1266  // [dcl.decomp]p4:
1267  // Otherwise, all of E's non-static data members shall be public direct
1268  // members of E ...
1269  ClassWithFields = RD;
1270  else {
1271  // ... or of ...
1272  CXXBasePaths Paths;
1273  Paths.setOrigin(const_cast<CXXRecordDecl*>(RD));
1274  if (!RD->lookupInBases(BaseHasFields, Paths)) {
1275  // If no classes have fields, just decompose RD itself. (This will work
1276  // if and only if zero bindings were provided.)
1277  return DeclAccessPair::make(const_cast<CXXRecordDecl*>(RD), AS_public);
1278  }
1279 
1280  CXXBasePath *BestPath = nullptr;
1281  for (auto &P : Paths) {
1282  if (!BestPath)
1283  BestPath = &P;
1284  else if (!S.Context.hasSameType(P.back().Base->getType(),
1285  BestPath->back().Base->getType())) {
1286  // ... the same ...
1287  S.Diag(Loc, diag::err_decomp_decl_multiple_bases_with_members)
1288  << false << RD << BestPath->back().Base->getType()
1289  << P.back().Base->getType();
1290  return DeclAccessPair();
1291  } else if (P.Access < BestPath->Access) {
1292  BestPath = &P;
1293  }
1294  }
1295 
1296  // ... unambiguous ...
1297  QualType BaseType = BestPath->back().Base->getType();
1298  if (Paths.isAmbiguous(S.Context.getCanonicalType(BaseType))) {
1299  S.Diag(Loc, diag::err_decomp_decl_ambiguous_base)
1300  << RD << BaseType << S.getAmbiguousPathsDisplayString(Paths);
1301  return DeclAccessPair();
1302  }
1303 
1304  // ... [accessible, implied by other rules] base class of E.
1305  S.CheckBaseClassAccess(Loc, BaseType, S.Context.getRecordType(RD),
1306  *BestPath, diag::err_decomp_decl_inaccessible_base);
1307  AS = BestPath->Access;
1308 
1309  ClassWithFields = BaseType->getAsCXXRecordDecl();
1310  S.BuildBasePathArray(Paths, BasePath);
1311  }
1312 
1313  // The above search did not check whether the selected class itself has base
1314  // classes with fields, so check that now.
1315  CXXBasePaths Paths;
1316  if (ClassWithFields->lookupInBases(BaseHasFields, Paths)) {
1317  S.Diag(Loc, diag::err_decomp_decl_multiple_bases_with_members)
1318  << (ClassWithFields == RD) << RD << ClassWithFields
1319  << Paths.front().back().Base->getType();
1320  return DeclAccessPair();
1321  }
1322 
1323  return DeclAccessPair::make(const_cast<CXXRecordDecl*>(ClassWithFields), AS);
1324 }
1325 
1327  ValueDecl *Src, QualType DecompType,
1328  const CXXRecordDecl *OrigRD) {
1329  if (S.RequireCompleteType(Src->getLocation(), DecompType,
1330  diag::err_incomplete_type))
1331  return true;
1332 
1333  CXXCastPath BasePath;
1334  DeclAccessPair BasePair =
1335  findDecomposableBaseClass(S, Src->getLocation(), OrigRD, BasePath);
1336  const CXXRecordDecl *RD = cast_or_null<CXXRecordDecl>(BasePair.getDecl());
1337  if (!RD)
1338  return true;
1340  DecompType.getQualifiers());
1341 
1342  auto DiagnoseBadNumberOfBindings = [&]() -> bool {
1343  unsigned NumFields =
1344  std::count_if(RD->field_begin(), RD->field_end(),
1345  [](FieldDecl *FD) { return !FD->isUnnamedBitfield(); });
1346  assert(Bindings.size() != NumFields);
1347  S.Diag(Src->getLocation(), diag::err_decomp_decl_wrong_number_bindings)
1348  << DecompType << (unsigned)Bindings.size() << NumFields
1349  << (NumFields < Bindings.size());
1350  return true;
1351  };
1352 
1353  // all of E's non-static data members shall be [...] well-formed
1354  // when named as e.name in the context of the structured binding,
1355  // E shall not have an anonymous union member, ...
1356  unsigned I = 0;
1357  for (auto *FD : RD->fields()) {
1358  if (FD->isUnnamedBitfield())
1359  continue;
1360 
1361  if (FD->isAnonymousStructOrUnion()) {
1362  S.Diag(Src->getLocation(), diag::err_decomp_decl_anon_union_member)
1363  << DecompType << FD->getType()->isUnionType();
1364  S.Diag(FD->getLocation(), diag::note_declared_at);
1365  return true;
1366  }
1367 
1368  // We have a real field to bind.
1369  if (I >= Bindings.size())
1370  return DiagnoseBadNumberOfBindings();
1371  auto *B = Bindings[I++];
1372  SourceLocation Loc = B->getLocation();
1373 
1374  // The field must be accessible in the context of the structured binding.
1375  // We already checked that the base class is accessible.
1376  // FIXME: Add 'const' to AccessedEntity's classes so we can remove the
1377  // const_cast here.
1379  Loc, const_cast<CXXRecordDecl *>(OrigRD),
1381  BasePair.getAccess(), FD->getAccess())));
1382 
1383  // Initialize the binding to Src.FD.
1384  ExprResult E = S.BuildDeclRefExpr(Src, DecompType, VK_LValue, Loc);
1385  if (E.isInvalid())
1386  return true;
1387  E = S.ImpCastExprToType(E.get(), BaseType, CK_UncheckedDerivedToBase,
1388  VK_LValue, &BasePath);
1389  if (E.isInvalid())
1390  return true;
1391  E = S.BuildFieldReferenceExpr(E.get(), /*IsArrow*/ false, Loc,
1392  CXXScopeSpec(), FD,
1393  DeclAccessPair::make(FD, FD->getAccess()),
1394  DeclarationNameInfo(FD->getDeclName(), Loc));
1395  if (E.isInvalid())
1396  return true;
1397 
1398  // If the type of the member is T, the referenced type is cv T, where cv is
1399  // the cv-qualification of the decomposition expression.
1400  //
1401  // FIXME: We resolve a defect here: if the field is mutable, we do not add
1402  // 'const' to the type of the field.
1403  Qualifiers Q = DecompType.getQualifiers();
1404  if (FD->isMutable())
1405  Q.removeConst();
1406  B->setBinding(S.BuildQualifiedType(FD->getType(), Loc, Q), E.get());
1407  }
1408 
1409  if (I != Bindings.size())
1410  return DiagnoseBadNumberOfBindings();
1411 
1412  return false;
1413 }
1414 
1416  QualType DecompType = DD->getType();
1417 
1418  // If the type of the decomposition is dependent, then so is the type of
1419  // each binding.
1420  if (DecompType->isDependentType()) {
1421  for (auto *B : DD->bindings())
1422  B->setType(Context.DependentTy);
1423  return;
1424  }
1425 
1426  DecompType = DecompType.getNonReferenceType();
1427  ArrayRef<BindingDecl*> Bindings = DD->bindings();
1428 
1429  // C++1z [dcl.decomp]/2:
1430  // If E is an array type [...]
1431  // As an extension, we also support decomposition of built-in complex and
1432  // vector types.
1433  if (auto *CAT = Context.getAsConstantArrayType(DecompType)) {
1434  if (checkArrayDecomposition(*this, Bindings, DD, DecompType, CAT))
1435  DD->setInvalidDecl();
1436  return;
1437  }
1438  if (auto *VT = DecompType->getAs<VectorType>()) {
1439  if (checkVectorDecomposition(*this, Bindings, DD, DecompType, VT))
1440  DD->setInvalidDecl();
1441  return;
1442  }
1443  if (auto *CT = DecompType->getAs<ComplexType>()) {
1444  if (checkComplexDecomposition(*this, Bindings, DD, DecompType, CT))
1445  DD->setInvalidDecl();
1446  return;
1447  }
1448 
1449  // C++1z [dcl.decomp]/3:
1450  // if the expression std::tuple_size<E>::value is a well-formed integral
1451  // constant expression, [...]
1452  llvm::APSInt TupleSize(32);
1453  switch (isTupleLike(*this, DD->getLocation(), DecompType, TupleSize)) {
1454  case IsTupleLike::Error:
1455  DD->setInvalidDecl();
1456  return;
1457 
1458  case IsTupleLike::TupleLike:
1459  if (checkTupleLikeDecomposition(*this, Bindings, DD, DecompType, TupleSize))
1460  DD->setInvalidDecl();
1461  return;
1462 
1463  case IsTupleLike::NotTupleLike:
1464  break;
1465  }
1466 
1467  // C++1z [dcl.dcl]/8:
1468  // [E shall be of array or non-union class type]
1469  CXXRecordDecl *RD = DecompType->getAsCXXRecordDecl();
1470  if (!RD || RD->isUnion()) {
1471  Diag(DD->getLocation(), diag::err_decomp_decl_unbindable_type)
1472  << DD << !RD << DecompType;
1473  DD->setInvalidDecl();
1474  return;
1475  }
1476 
1477  // C++1z [dcl.decomp]/4:
1478  // all of E's non-static data members shall be [...] direct members of
1479  // E or of the same unambiguous public base class of E, ...
1480  if (checkMemberDecomposition(*this, Bindings, DD, DecompType, RD))
1481  DD->setInvalidDecl();
1482 }
1483 
1484 /// Merge the exception specifications of two variable declarations.
1485 ///
1486 /// This is called when there's a redeclaration of a VarDecl. The function
1487 /// checks if the redeclaration might have an exception specification and
1488 /// validates compatibility and merges the specs if necessary.
1490  // Shortcut if exceptions are disabled.
1491  if (!getLangOpts().CXXExceptions)
1492  return;
1493 
1494  assert(Context.hasSameType(New->getType(), Old->getType()) &&
1495  "Should only be called if types are otherwise the same.");
1496 
1497  QualType NewType = New->getType();
1498  QualType OldType = Old->getType();
1499 
1500  // We're only interested in pointers and references to functions, as well
1501  // as pointers to member functions.
1502  if (const ReferenceType *R = NewType->getAs<ReferenceType>()) {
1503  NewType = R->getPointeeType();
1504  OldType = OldType->getAs<ReferenceType>()->getPointeeType();
1505  } else if (const PointerType *P = NewType->getAs<PointerType>()) {
1506  NewType = P->getPointeeType();
1507  OldType = OldType->getAs<PointerType>()->getPointeeType();
1508  } else if (const MemberPointerType *M = NewType->getAs<MemberPointerType>()) {
1509  NewType = M->getPointeeType();
1510  OldType = OldType->getAs<MemberPointerType>()->getPointeeType();
1511  }
1512 
1513  if (!NewType->isFunctionProtoType())
1514  return;
1515 
1516  // There's lots of special cases for functions. For function pointers, system
1517  // libraries are hopefully not as broken so that we don't need these
1518  // workarounds.
1519  if (CheckEquivalentExceptionSpec(
1520  OldType->getAs<FunctionProtoType>(), Old->getLocation(),
1521  NewType->getAs<FunctionProtoType>(), New->getLocation())) {
1522  New->setInvalidDecl();
1523  }
1524 }
1525 
1526 /// CheckCXXDefaultArguments - Verify that the default arguments for a
1527 /// function declaration are well-formed according to C++
1528 /// [dcl.fct.default].
1530  unsigned NumParams = FD->getNumParams();
1531  unsigned p;
1532 
1533  // Find first parameter with a default argument
1534  for (p = 0; p < NumParams; ++p) {
1535  ParmVarDecl *Param = FD->getParamDecl(p);
1536  if (Param->hasDefaultArg())
1537  break;
1538  }
1539 
1540  // C++11 [dcl.fct.default]p4:
1541  // In a given function declaration, each parameter subsequent to a parameter
1542  // with a default argument shall have a default argument supplied in this or
1543  // a previous declaration or shall be a function parameter pack. A default
1544  // argument shall not be redefined by a later declaration (not even to the
1545  // same value).
1546  unsigned LastMissingDefaultArg = 0;
1547  for (; p < NumParams; ++p) {
1548  ParmVarDecl *Param = FD->getParamDecl(p);
1549  if (!Param->hasDefaultArg() && !Param->isParameterPack()) {
1550  if (Param->isInvalidDecl())
1551  /* We already complained about this parameter. */;
1552  else if (Param->getIdentifier())
1553  Diag(Param->getLocation(),
1554  diag::err_param_default_argument_missing_name)
1555  << Param->getIdentifier();
1556  else
1557  Diag(Param->getLocation(),
1558  diag::err_param_default_argument_missing);
1559 
1560  LastMissingDefaultArg = p;
1561  }
1562  }
1563 
1564  if (LastMissingDefaultArg > 0) {
1565  // Some default arguments were missing. Clear out all of the
1566  // default arguments up to (and including) the last missing
1567  // default argument, so that we leave the function parameters
1568  // in a semantically valid state.
1569  for (p = 0; p <= LastMissingDefaultArg; ++p) {
1570  ParmVarDecl *Param = FD->getParamDecl(p);
1571  if (Param->hasDefaultArg()) {
1572  Param->setDefaultArg(nullptr);
1573  }
1574  }
1575  }
1576 }
1577 
1578 /// Check that the given type is a literal type. Issue a diagnostic if not,
1579 /// if Kind is Diagnose.
1580 /// \return \c true if a problem has been found (and optionally diagnosed).
1581 template <typename... Ts>
1583  SourceLocation Loc, QualType T, unsigned DiagID,
1584  Ts &&...DiagArgs) {
1585  if (T->isDependentType())
1586  return false;
1587 
1588  switch (Kind) {
1590  return SemaRef.RequireLiteralType(Loc, T, DiagID,
1591  std::forward<Ts>(DiagArgs)...);
1592 
1594  return !T->isLiteralType(SemaRef.Context);
1595  }
1596 
1597  llvm_unreachable("unknown CheckConstexprKind");
1598 }
1599 
1600 /// Determine whether a destructor cannot be constexpr due to
1602  const CXXDestructorDecl *DD,
1604  auto Check = [&](SourceLocation Loc, QualType T, const FieldDecl *FD) {
1605  const CXXRecordDecl *RD =
1606  T->getBaseElementTypeUnsafe()->getAsCXXRecordDecl();
1607  if (!RD || RD->hasConstexprDestructor())
1608  return true;
1609 
1610  if (Kind == Sema::CheckConstexprKind::Diagnose) {
1611  SemaRef.Diag(DD->getLocation(), diag::err_constexpr_dtor_subobject)
1612  << DD->getConstexprKind() << !FD
1613  << (FD ? FD->getDeclName() : DeclarationName()) << T;
1614  SemaRef.Diag(Loc, diag::note_constexpr_dtor_subobject)
1615  << !FD << (FD ? FD->getDeclName() : DeclarationName()) << T;
1616  }
1617  return false;
1618  };
1619 
1620  const CXXRecordDecl *RD = DD->getParent();
1621  for (const CXXBaseSpecifier &B : RD->bases())
1622  if (!Check(B.getBaseTypeLoc(), B.getType(), nullptr))
1623  return false;
1624  for (const FieldDecl *FD : RD->fields())
1625  if (!Check(FD->getLocation(), FD->getType(), FD))
1626  return false;
1627  return true;
1628 }
1629 
1630 // CheckConstexprParameterTypes - Check whether a function's parameter types
1631 // are all literal types. If so, return true. If not, produce a suitable
1632 // diagnostic and return false.
1633 static bool CheckConstexprParameterTypes(Sema &SemaRef,
1634  const FunctionDecl *FD,
1636  unsigned ArgIndex = 0;
1637  const FunctionProtoType *FT = FD->getType()->getAs<FunctionProtoType>();
1639  e = FT->param_type_end();
1640  i != e; ++i, ++ArgIndex) {
1641  const ParmVarDecl *PD = FD->getParamDecl(ArgIndex);
1642  SourceLocation ParamLoc = PD->getLocation();
1643  if (CheckLiteralType(SemaRef, Kind, ParamLoc, *i,
1644  diag::err_constexpr_non_literal_param, ArgIndex + 1,
1645  PD->getSourceRange(), isa<CXXConstructorDecl>(FD),
1646  FD->isConsteval()))
1647  return false;
1648  }
1649  return true;
1650 }
1651 
1652 /// Get diagnostic %select index for tag kind for
1653 /// record diagnostic message.
1654 /// WARNING: Indexes apply to particular diagnostics only!
1655 ///
1656 /// \returns diagnostic %select index.
1658  switch (Tag) {
1659  case TTK_Struct: return 0;
1660  case TTK_Interface: return 1;
1661  case TTK_Class: return 2;
1662  default: llvm_unreachable("Invalid tag kind for record diagnostic!");
1663  }
1664 }
1665 
1666 static bool CheckConstexprFunctionBody(Sema &SemaRef, const FunctionDecl *Dcl,
1667  Stmt *Body,
1669 
1670 // Check whether a function declaration satisfies the requirements of a
1671 // constexpr function definition or a constexpr constructor definition. If so,
1672 // return true. If not, produce appropriate diagnostics (unless asked not to by
1673 // Kind) and return false.
1674 //
1675 // This implements C++11 [dcl.constexpr]p3,4, as amended by DR1360.
1677  CheckConstexprKind Kind) {
1678  const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(NewFD);
1679  if (MD && MD->isInstance()) {
1680  // C++11 [dcl.constexpr]p4:
1681  // The definition of a constexpr constructor shall satisfy the following
1682  // constraints:
1683  // - the class shall not have any virtual base classes;
1684  //
1685  // FIXME: This only applies to constructors and destructors, not arbitrary
1686  // member functions.
1687  const CXXRecordDecl *RD = MD->getParent();
1688  if (RD->getNumVBases()) {
1689  if (Kind == CheckConstexprKind::CheckValid)
1690  return false;
1691 
1692  Diag(NewFD->getLocation(), diag::err_constexpr_virtual_base)
1693  << isa<CXXConstructorDecl>(NewFD)
1695  for (const auto &I : RD->vbases())
1696  Diag(I.getBeginLoc(), diag::note_constexpr_virtual_base_here)
1697  << I.getSourceRange();
1698  return false;
1699  }
1700  }
1701 
1702  if (!isa<CXXConstructorDecl>(NewFD)) {
1703  // C++11 [dcl.constexpr]p3:
1704  // The definition of a constexpr function shall satisfy the following
1705  // constraints:
1706  // - it shall not be virtual; (removed in C++20)
1707  const CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(NewFD);
1708  if (Method && Method->isVirtual()) {
1709  if (getLangOpts().CPlusPlus2a) {
1710  if (Kind == CheckConstexprKind::Diagnose)
1711  Diag(Method->getLocation(), diag::warn_cxx17_compat_constexpr_virtual);
1712  } else {
1713  if (Kind == CheckConstexprKind::CheckValid)
1714  return false;
1715 
1716  Method = Method->getCanonicalDecl();
1717  Diag(Method->getLocation(), diag::err_constexpr_virtual);
1718 
1719  // If it's not obvious why this function is virtual, find an overridden
1720  // function which uses the 'virtual' keyword.
1721  const CXXMethodDecl *WrittenVirtual = Method;
1722  while (!WrittenVirtual->isVirtualAsWritten())
1723  WrittenVirtual = *WrittenVirtual->begin_overridden_methods();
1724  if (WrittenVirtual != Method)
1725  Diag(WrittenVirtual->getLocation(),
1726  diag::note_overridden_virtual_function);
1727  return false;
1728  }
1729  }
1730 
1731  // - its return type shall be a literal type;
1732  QualType RT = NewFD->getReturnType();
1733  if (CheckLiteralType(*this, Kind, NewFD->getLocation(), RT,
1734  diag::err_constexpr_non_literal_return,
1735  NewFD->isConsteval()))
1736  return false;
1737  }
1738 
1739  if (auto *Dtor = dyn_cast<CXXDestructorDecl>(NewFD)) {
1740  // A destructor can be constexpr only if the defaulted destructor could be;
1741  // we don't need to check the members and bases if we already know they all
1742  // have constexpr destructors.
1743  if (!Dtor->getParent()->defaultedDestructorIsConstexpr()) {
1744  if (Kind == CheckConstexprKind::CheckValid)
1745  return false;
1746  if (!CheckConstexprDestructorSubobjects(*this, Dtor, Kind))
1747  return false;
1748  }
1749  }
1750 
1751  // - each of its parameter types shall be a literal type;
1752  if (!CheckConstexprParameterTypes(*this, NewFD, Kind))
1753  return false;
1754 
1755  Stmt *Body = NewFD->getBody();
1756  assert(Body &&
1757  "CheckConstexprFunctionDefinition called on function with no body");
1758  return CheckConstexprFunctionBody(*this, NewFD, Body, Kind);
1759 }
1760 
1761 /// Check the given declaration statement is legal within a constexpr function
1762 /// body. C++11 [dcl.constexpr]p3,p4, and C++1y [dcl.constexpr]p3.
1763 ///
1764 /// \return true if the body is OK (maybe only as an extension), false if we
1765 /// have diagnosed a problem.
1766 static bool CheckConstexprDeclStmt(Sema &SemaRef, const FunctionDecl *Dcl,
1767  DeclStmt *DS, SourceLocation &Cxx1yLoc,
1768  Sema::CheckConstexprKind Kind) {
1769  // C++11 [dcl.constexpr]p3 and p4:
1770  // The definition of a constexpr function(p3) or constructor(p4) [...] shall
1771  // contain only
1772  for (const auto *DclIt : DS->decls()) {
1773  switch (DclIt->getKind()) {
1774  case Decl::StaticAssert:
1775  case Decl::Using:
1776  case Decl::UsingShadow:
1777  case Decl::UsingDirective:
1778  case Decl::UnresolvedUsingTypename:
1779  case Decl::UnresolvedUsingValue:
1780  // - static_assert-declarations
1781  // - using-declarations,
1782  // - using-directives,
1783  continue;
1784 
1785  case Decl::Typedef:
1786  case Decl::TypeAlias: {
1787  // - typedef declarations and alias-declarations that do not define
1788  // classes or enumerations,
1789  const auto *TN = cast<TypedefNameDecl>(DclIt);
1790  if (TN->getUnderlyingType()->isVariablyModifiedType()) {
1791  // Don't allow variably-modified types in constexpr functions.
1792  if (Kind == Sema::CheckConstexprKind::Diagnose) {
1793  TypeLoc TL = TN->getTypeSourceInfo()->getTypeLoc();
1794  SemaRef.Diag(TL.getBeginLoc(), diag::err_constexpr_vla)
1795  << TL.getSourceRange() << TL.getType()
1796  << isa<CXXConstructorDecl>(Dcl);
1797  }
1798  return false;
1799  }
1800  continue;
1801  }
1802 
1803  case Decl::Enum:
1804  case Decl::CXXRecord:
1805  // C++1y allows types to be defined, not just declared.
1806  if (cast<TagDecl>(DclIt)->isThisDeclarationADefinition()) {
1807  if (Kind == Sema::CheckConstexprKind::Diagnose) {
1808  SemaRef.Diag(DS->getBeginLoc(),
1809  SemaRef.getLangOpts().CPlusPlus14
1810  ? diag::warn_cxx11_compat_constexpr_type_definition
1811  : diag::ext_constexpr_type_definition)
1812  << isa<CXXConstructorDecl>(Dcl);
1813  } else if (!SemaRef.getLangOpts().CPlusPlus14) {
1814  return false;
1815  }
1816  }
1817  continue;
1818 
1819  case Decl::EnumConstant:
1820  case Decl::IndirectField:
1821  case Decl::ParmVar:
1822  // These can only appear with other declarations which are banned in
1823  // C++11 and permitted in C++1y, so ignore them.
1824  continue;
1825 
1826  case Decl::Var:
1827  case Decl::Decomposition: {
1828  // C++1y [dcl.constexpr]p3 allows anything except:
1829  // a definition of a variable of non-literal type or of static or
1830  // thread storage duration or [before C++2a] for which no
1831  // initialization is performed.
1832  const auto *VD = cast<VarDecl>(DclIt);
1833  if (VD->isThisDeclarationADefinition()) {
1834  if (VD->isStaticLocal()) {
1835  if (Kind == Sema::CheckConstexprKind::Diagnose) {
1836  SemaRef.Diag(VD->getLocation(),
1837  diag::err_constexpr_local_var_static)
1838  << isa<CXXConstructorDecl>(Dcl)
1839  << (VD->getTLSKind() == VarDecl::TLS_Dynamic);
1840  }
1841  return false;
1842  }
1843  if (CheckLiteralType(SemaRef, Kind, VD->getLocation(), VD->getType(),
1844  diag::err_constexpr_local_var_non_literal_type,
1845  isa<CXXConstructorDecl>(Dcl)))
1846  return false;
1847  if (!VD->getType()->isDependentType() &&
1848  !VD->hasInit() && !VD->isCXXForRangeDecl()) {
1849  if (Kind == Sema::CheckConstexprKind::Diagnose) {
1850  SemaRef.Diag(
1851  VD->getLocation(),
1852  SemaRef.getLangOpts().CPlusPlus2a
1853  ? diag::warn_cxx17_compat_constexpr_local_var_no_init
1854  : diag::ext_constexpr_local_var_no_init)
1855  << isa<CXXConstructorDecl>(Dcl);
1856  } else if (!SemaRef.getLangOpts().CPlusPlus2a) {
1857  return false;
1858  }
1859  continue;
1860  }
1861  }
1862  if (Kind == Sema::CheckConstexprKind::Diagnose) {
1863  SemaRef.Diag(VD->getLocation(),
1864  SemaRef.getLangOpts().CPlusPlus14
1865  ? diag::warn_cxx11_compat_constexpr_local_var
1866  : diag::ext_constexpr_local_var)
1867  << isa<CXXConstructorDecl>(Dcl);
1868  } else if (!SemaRef.getLangOpts().CPlusPlus14) {
1869  return false;
1870  }
1871  continue;
1872  }
1873 
1874  case Decl::NamespaceAlias:
1875  case Decl::Function:
1876  // These are disallowed in C++11 and permitted in C++1y. Allow them
1877  // everywhere as an extension.
1878  if (!Cxx1yLoc.isValid())
1879  Cxx1yLoc = DS->getBeginLoc();
1880  continue;
1881 
1882  default:
1883  if (Kind == Sema::CheckConstexprKind::Diagnose) {
1884  SemaRef.Diag(DS->getBeginLoc(), diag::err_constexpr_body_invalid_stmt)
1885  << isa<CXXConstructorDecl>(Dcl) << Dcl->isConsteval();
1886  }
1887  return false;
1888  }
1889  }
1890 
1891  return true;
1892 }
1893 
1894 /// Check that the given field is initialized within a constexpr constructor.
1895 ///
1896 /// \param Dcl The constexpr constructor being checked.
1897 /// \param Field The field being checked. This may be a member of an anonymous
1898 /// struct or union nested within the class being checked.
1899 /// \param Inits All declarations, including anonymous struct/union members and
1900 /// indirect members, for which any initialization was provided.
1901 /// \param Diagnosed Whether we've emitted the error message yet. Used to attach
1902 /// multiple notes for different members to the same error.
1903 /// \param Kind Whether we're diagnosing a constructor as written or determining
1904 /// whether the formal requirements are satisfied.
1905 /// \return \c false if we're checking for validity and the constructor does
1906 /// not satisfy the requirements on a constexpr constructor.
1908  const FunctionDecl *Dcl,
1909  FieldDecl *Field,
1910  llvm::SmallSet<Decl*, 16> &Inits,
1911  bool &Diagnosed,
1912  Sema::CheckConstexprKind Kind) {
1913  // In C++20 onwards, there's nothing to check for validity.
1915  SemaRef.getLangOpts().CPlusPlus2a)
1916  return true;
1917 
1918  if (Field->isInvalidDecl())
1919  return true;
1920 
1921  if (Field->isUnnamedBitfield())
1922  return true;
1923 
1924  // Anonymous unions with no variant members and empty anonymous structs do not
1925  // need to be explicitly initialized. FIXME: Anonymous structs that contain no
1926  // indirect fields don't need initializing.
1927  if (Field->isAnonymousStructOrUnion() &&
1928  (Field->getType()->isUnionType()
1929  ? !Field->getType()->getAsCXXRecordDecl()->hasVariantMembers()
1930  : Field->getType()->getAsCXXRecordDecl()->isEmpty()))
1931  return true;
1932 
1933  if (!Inits.count(Field)) {
1934  if (Kind == Sema::CheckConstexprKind::Diagnose) {
1935  if (!Diagnosed) {
1936  SemaRef.Diag(Dcl->getLocation(),
1937  SemaRef.getLangOpts().CPlusPlus2a
1938  ? diag::warn_cxx17_compat_constexpr_ctor_missing_init
1939  : diag::ext_constexpr_ctor_missing_init);
1940  Diagnosed = true;
1941  }
1942  SemaRef.Diag(Field->getLocation(),
1943  diag::note_constexpr_ctor_missing_init);
1944  } else if (!SemaRef.getLangOpts().CPlusPlus2a) {
1945  return false;
1946  }
1947  } else if (Field->isAnonymousStructOrUnion()) {
1948  const RecordDecl *RD = Field->getType()->castAs<RecordType>()->getDecl();
1949  for (auto *I : RD->fields())
1950  // If an anonymous union contains an anonymous struct of which any member
1951  // is initialized, all members must be initialized.
1952  if (!RD->isUnion() || Inits.count(I))
1953  if (!CheckConstexprCtorInitializer(SemaRef, Dcl, I, Inits, Diagnosed,
1954  Kind))
1955  return false;
1956  }
1957  return true;
1958 }
1959 
1960 /// Check the provided statement is allowed in a constexpr function
1961 /// definition.
1962 static bool
1964  SmallVectorImpl<SourceLocation> &ReturnStmts,
1965  SourceLocation &Cxx1yLoc, SourceLocation &Cxx2aLoc,
1966  Sema::CheckConstexprKind Kind) {
1967  // - its function-body shall be [...] a compound-statement that contains only
1968  switch (S->getStmtClass()) {
1969  case Stmt::NullStmtClass:
1970  // - null statements,
1971  return true;
1972 
1973  case Stmt::DeclStmtClass:
1974  // - static_assert-declarations
1975  // - using-declarations,
1976  // - using-directives,
1977  // - typedef declarations and alias-declarations that do not define
1978  // classes or enumerations,
1979  if (!CheckConstexprDeclStmt(SemaRef, Dcl, cast<DeclStmt>(S), Cxx1yLoc, Kind))
1980  return false;
1981  return true;
1982 
1983  case Stmt::ReturnStmtClass:
1984  // - and exactly one return statement;
1985  if (isa<CXXConstructorDecl>(Dcl)) {
1986  // C++1y allows return statements in constexpr constructors.
1987  if (!Cxx1yLoc.isValid())
1988  Cxx1yLoc = S->getBeginLoc();
1989  return true;
1990  }
1991 
1992  ReturnStmts.push_back(S->getBeginLoc());
1993  return true;
1994 
1995  case Stmt::CompoundStmtClass: {
1996  // C++1y allows compound-statements.
1997  if (!Cxx1yLoc.isValid())
1998  Cxx1yLoc = S->getBeginLoc();
1999 
2000  CompoundStmt *CompStmt = cast<CompoundStmt>(S);
2001  for (auto *BodyIt : CompStmt->body()) {
2002  if (!CheckConstexprFunctionStmt(SemaRef, Dcl, BodyIt, ReturnStmts,
2003  Cxx1yLoc, Cxx2aLoc, Kind))
2004  return false;
2005  }
2006  return true;
2007  }
2008 
2009  case Stmt::AttributedStmtClass:
2010  if (!Cxx1yLoc.isValid())
2011  Cxx1yLoc = S->getBeginLoc();
2012  return true;
2013 
2014  case Stmt::IfStmtClass: {
2015  // C++1y allows if-statements.
2016  if (!Cxx1yLoc.isValid())
2017  Cxx1yLoc = S->getBeginLoc();
2018 
2019  IfStmt *If = cast<IfStmt>(S);
2020  if (!CheckConstexprFunctionStmt(SemaRef, Dcl, If->getThen(), ReturnStmts,
2021  Cxx1yLoc, Cxx2aLoc, Kind))
2022  return false;
2023  if (If->getElse() &&
2024  !CheckConstexprFunctionStmt(SemaRef, Dcl, If->getElse(), ReturnStmts,
2025  Cxx1yLoc, Cxx2aLoc, Kind))
2026  return false;
2027  return true;
2028  }
2029 
2030  case Stmt::WhileStmtClass:
2031  case Stmt::DoStmtClass:
2032  case Stmt::ForStmtClass:
2033  case Stmt::CXXForRangeStmtClass:
2034  case Stmt::ContinueStmtClass:
2035  // C++1y allows all of these. We don't allow them as extensions in C++11,
2036  // because they don't make sense without variable mutation.
2037  if (!SemaRef.getLangOpts().CPlusPlus14)
2038  break;
2039  if (!Cxx1yLoc.isValid())
2040  Cxx1yLoc = S->getBeginLoc();
2041  for (Stmt *SubStmt : S->children())
2042  if (SubStmt &&
2043  !CheckConstexprFunctionStmt(SemaRef, Dcl, SubStmt, ReturnStmts,
2044  Cxx1yLoc, Cxx2aLoc, Kind))
2045  return false;
2046  return true;
2047 
2048  case Stmt::SwitchStmtClass:
2049  case Stmt::CaseStmtClass:
2050  case Stmt::DefaultStmtClass:
2051  case Stmt::BreakStmtClass:
2052  // C++1y allows switch-statements, and since they don't need variable
2053  // mutation, we can reasonably allow them in C++11 as an extension.
2054  if (!Cxx1yLoc.isValid())
2055  Cxx1yLoc = S->getBeginLoc();
2056  for (Stmt *SubStmt : S->children())
2057  if (SubStmt &&
2058  !CheckConstexprFunctionStmt(SemaRef, Dcl, SubStmt, ReturnStmts,
2059  Cxx1yLoc, Cxx2aLoc, Kind))
2060  return false;
2061  return true;
2062 
2063  case Stmt::GCCAsmStmtClass:
2064  case Stmt::MSAsmStmtClass:
2065  // C++2a allows inline assembly statements.
2066  case Stmt::CXXTryStmtClass:
2067  if (Cxx2aLoc.isInvalid())
2068  Cxx2aLoc = S->getBeginLoc();
2069  for (Stmt *SubStmt : S->children()) {
2070  if (SubStmt &&
2071  !CheckConstexprFunctionStmt(SemaRef, Dcl, SubStmt, ReturnStmts,
2072  Cxx1yLoc, Cxx2aLoc, Kind))
2073  return false;
2074  }
2075  return true;
2076 
2077  case Stmt::CXXCatchStmtClass:
2078  // Do not bother checking the language mode (already covered by the
2079  // try block check).
2080  if (!CheckConstexprFunctionStmt(SemaRef, Dcl,
2081  cast<CXXCatchStmt>(S)->getHandlerBlock(),
2082  ReturnStmts, Cxx1yLoc, Cxx2aLoc, Kind))
2083  return false;
2084  return true;
2085 
2086  default:
2087  if (!isa<Expr>(S))
2088  break;
2089 
2090  // C++1y allows expression-statements.
2091  if (!Cxx1yLoc.isValid())
2092  Cxx1yLoc = S->getBeginLoc();
2093  return true;
2094  }
2095 
2096  if (Kind == Sema::CheckConstexprKind::Diagnose) {
2097  SemaRef.Diag(S->getBeginLoc(), diag::err_constexpr_body_invalid_stmt)
2098  << isa<CXXConstructorDecl>(Dcl) << Dcl->isConsteval();
2099  }
2100  return false;
2101 }
2102 
2103 /// Check the body for the given constexpr function declaration only contains
2104 /// the permitted types of statement. C++11 [dcl.constexpr]p3,p4.
2105 ///
2106 /// \return true if the body is OK, false if we have found or diagnosed a
2107 /// problem.
2108 static bool CheckConstexprFunctionBody(Sema &SemaRef, const FunctionDecl *Dcl,
2109  Stmt *Body,
2110  Sema::CheckConstexprKind Kind) {
2111  SmallVector<SourceLocation, 4> ReturnStmts;
2112 
2113  if (isa<CXXTryStmt>(Body)) {
2114  // C++11 [dcl.constexpr]p3:
2115  // The definition of a constexpr function shall satisfy the following
2116  // constraints: [...]
2117  // - its function-body shall be = delete, = default, or a
2118  // compound-statement
2119  //
2120  // C++11 [dcl.constexpr]p4:
2121  // In the definition of a constexpr constructor, [...]
2122  // - its function-body shall not be a function-try-block;
2123  //
2124  // This restriction is lifted in C++2a, as long as inner statements also
2125  // apply the general constexpr rules.
2126  switch (Kind) {
2128  if (!SemaRef.getLangOpts().CPlusPlus2a)
2129  return false;
2130  break;
2131 
2133  SemaRef.Diag(Body->getBeginLoc(),
2134  !SemaRef.getLangOpts().CPlusPlus2a
2135  ? diag::ext_constexpr_function_try_block_cxx2a
2136  : diag::warn_cxx17_compat_constexpr_function_try_block)
2137  << isa<CXXConstructorDecl>(Dcl);
2138  break;
2139  }
2140  }
2141 
2142  // - its function-body shall be [...] a compound-statement that contains only
2143  // [... list of cases ...]
2144  //
2145  // Note that walking the children here is enough to properly check for
2146  // CompoundStmt and CXXTryStmt body.
2147  SourceLocation Cxx1yLoc, Cxx2aLoc;
2148  for (Stmt *SubStmt : Body->children()) {
2149  if (SubStmt &&
2150  !CheckConstexprFunctionStmt(SemaRef, Dcl, SubStmt, ReturnStmts,
2151  Cxx1yLoc, Cxx2aLoc, Kind))
2152  return false;
2153  }
2154 
2156  // If this is only valid as an extension, report that we don't satisfy the
2157  // constraints of the current language.
2158  if ((Cxx2aLoc.isValid() && !SemaRef.getLangOpts().CPlusPlus2a) ||
2159  (Cxx1yLoc.isValid() && !SemaRef.getLangOpts().CPlusPlus17))
2160  return false;
2161  } else if (Cxx2aLoc.isValid()) {
2162  SemaRef.Diag(Cxx2aLoc,
2163  SemaRef.getLangOpts().CPlusPlus2a
2164  ? diag::warn_cxx17_compat_constexpr_body_invalid_stmt
2165  : diag::ext_constexpr_body_invalid_stmt_cxx2a)
2166  << isa<CXXConstructorDecl>(Dcl);
2167  } else if (Cxx1yLoc.isValid()) {
2168  SemaRef.Diag(Cxx1yLoc,
2169  SemaRef.getLangOpts().CPlusPlus14
2170  ? diag::warn_cxx11_compat_constexpr_body_invalid_stmt
2171  : diag::ext_constexpr_body_invalid_stmt)
2172  << isa<CXXConstructorDecl>(Dcl);
2173  }
2174 
2175  if (const CXXConstructorDecl *Constructor
2176  = dyn_cast<CXXConstructorDecl>(Dcl)) {
2177  const CXXRecordDecl *RD = Constructor->getParent();
2178  // DR1359:
2179  // - every non-variant non-static data member and base class sub-object
2180  // shall be initialized;
2181  // DR1460:
2182  // - if the class is a union having variant members, exactly one of them
2183  // shall be initialized;
2184  if (RD->isUnion()) {
2185  if (Constructor->getNumCtorInitializers() == 0 &&
2186  RD->hasVariantMembers()) {
2187  if (Kind == Sema::CheckConstexprKind::Diagnose) {
2188  SemaRef.Diag(
2189  Dcl->getLocation(),
2190  SemaRef.getLangOpts().CPlusPlus2a
2191  ? diag::warn_cxx17_compat_constexpr_union_ctor_no_init
2192  : diag::ext_constexpr_union_ctor_no_init);
2193  } else if (!SemaRef.getLangOpts().CPlusPlus2a) {
2194  return false;
2195  }
2196  }
2197  } else if (!Constructor->isDependentContext() &&
2198  !Constructor->isDelegatingConstructor()) {
2199  assert(RD->getNumVBases() == 0 && "constexpr ctor with virtual bases");
2200 
2201  // Skip detailed checking if we have enough initializers, and we would
2202  // allow at most one initializer per member.
2203  bool AnyAnonStructUnionMembers = false;
2204  unsigned Fields = 0;
2206  E = RD->field_end(); I != E; ++I, ++Fields) {
2207  if (I->isAnonymousStructOrUnion()) {
2208  AnyAnonStructUnionMembers = true;
2209  break;
2210  }
2211  }
2212  // DR1460:
2213  // - if the class is a union-like class, but is not a union, for each of
2214  // its anonymous union members having variant members, exactly one of
2215  // them shall be initialized;
2216  if (AnyAnonStructUnionMembers ||
2217  Constructor->getNumCtorInitializers() != RD->getNumBases() + Fields) {
2218  // Check initialization of non-static data members. Base classes are
2219  // always initialized so do not need to be checked. Dependent bases
2220  // might not have initializers in the member initializer list.
2221  llvm::SmallSet<Decl*, 16> Inits;
2222  for (const auto *I: Constructor->inits()) {
2223  if (FieldDecl *FD = I->getMember())
2224  Inits.insert(FD);
2225  else if (IndirectFieldDecl *ID = I->getIndirectMember())
2226  Inits.insert(ID->chain_begin(), ID->chain_end());
2227  }
2228 
2229  bool Diagnosed = false;
2230  for (auto *I : RD->fields())
2231  if (!CheckConstexprCtorInitializer(SemaRef, Dcl, I, Inits, Diagnosed,
2232  Kind))
2233  return false;
2234  }
2235  }
2236  } else {
2237  if (ReturnStmts.empty()) {
2238  // C++1y doesn't require constexpr functions to contain a 'return'
2239  // statement. We still do, unless the return type might be void, because
2240  // otherwise if there's no return statement, the function cannot
2241  // be used in a core constant expression.
2242  bool OK = SemaRef.getLangOpts().CPlusPlus14 &&
2243  (Dcl->getReturnType()->isVoidType() ||
2244  Dcl->getReturnType()->isDependentType());
2245  switch (Kind) {
2247  SemaRef.Diag(Dcl->getLocation(),
2248  OK ? diag::warn_cxx11_compat_constexpr_body_no_return
2249  : diag::err_constexpr_body_no_return)
2250  << Dcl->isConsteval();
2251  if (!OK)
2252  return false;
2253  break;
2254 
2256  // The formal requirements don't include this rule in C++14, even
2257  // though the "must be able to produce a constant expression" rules
2258  // still imply it in some cases.
2259  if (!SemaRef.getLangOpts().CPlusPlus14)
2260  return false;
2261  break;
2262  }
2263  } else if (ReturnStmts.size() > 1) {
2264  switch (Kind) {
2266  SemaRef.Diag(
2267  ReturnStmts.back(),
2268  SemaRef.getLangOpts().CPlusPlus14
2269  ? diag::warn_cxx11_compat_constexpr_body_multiple_return
2270  : diag::ext_constexpr_body_multiple_return);
2271  for (unsigned I = 0; I < ReturnStmts.size() - 1; ++I)
2272  SemaRef.Diag(ReturnStmts[I],
2273  diag::note_constexpr_body_previous_return);
2274  break;
2275 
2277  if (!SemaRef.getLangOpts().CPlusPlus14)
2278  return false;
2279  break;
2280  }
2281  }
2282  }
2283 
2284  // C++11 [dcl.constexpr]p5:
2285  // if no function argument values exist such that the function invocation
2286  // substitution would produce a constant expression, the program is
2287  // ill-formed; no diagnostic required.
2288  // C++11 [dcl.constexpr]p3:
2289  // - every constructor call and implicit conversion used in initializing the
2290  // return value shall be one of those allowed in a constant expression.
2291  // C++11 [dcl.constexpr]p4:
2292  // - every constructor involved in initializing non-static data members and
2293  // base class sub-objects shall be a constexpr constructor.
2294  //
2295  // Note that this rule is distinct from the "requirements for a constexpr
2296  // function", so is not checked in CheckValid mode.
2298  if (Kind == Sema::CheckConstexprKind::Diagnose &&
2299  !Expr::isPotentialConstantExpr(Dcl, Diags)) {
2300  SemaRef.Diag(Dcl->getLocation(),
2301  diag::ext_constexpr_function_never_constant_expr)
2302  << isa<CXXConstructorDecl>(Dcl);
2303  for (size_t I = 0, N = Diags.size(); I != N; ++I)
2304  SemaRef.Diag(Diags[I].first, Diags[I].second);
2305  // Don't return false here: we allow this for compatibility in
2306  // system headers.
2307  }
2308 
2309  return true;
2310 }
2311 
2312 /// Get the class that is directly named by the current context. This is the
2313 /// class for which an unqualified-id in this scope could name a constructor
2314 /// or destructor.
2315 ///
2316 /// If the scope specifier denotes a class, this will be that class.
2317 /// If the scope specifier is empty, this will be the class whose
2318 /// member-specification we are currently within. Otherwise, there
2319 /// is no such class.
2321  assert(getLangOpts().CPlusPlus && "No class names in C!");
2322 
2323  if (SS && SS->isInvalid())
2324  return nullptr;
2325 
2326  if (SS && SS->isNotEmpty()) {
2327  DeclContext *DC = computeDeclContext(*SS, true);
2328  return dyn_cast_or_null<CXXRecordDecl>(DC);
2329  }
2330 
2331  return dyn_cast_or_null<CXXRecordDecl>(CurContext);
2332 }
2333 
2334 /// isCurrentClassName - Determine whether the identifier II is the
2335 /// name of the class type currently being defined. In the case of
2336 /// nested classes, this will only return true if II is the name of
2337 /// the innermost class.
2339  const CXXScopeSpec *SS) {
2340  CXXRecordDecl *CurDecl = getCurrentClass(S, SS);
2341  return CurDecl && &II == CurDecl->getIdentifier();
2342 }
2343 
2344 /// Determine whether the identifier II is a typo for the name of
2345 /// the class type currently being defined. If so, update it to the identifier
2346 /// that should have been used.
2348  assert(getLangOpts().CPlusPlus && "No class names in C!");
2349 
2350  if (!getLangOpts().SpellChecking)
2351  return false;
2352 
2353  CXXRecordDecl *CurDecl;
2354  if (SS && SS->isSet() && !SS->isInvalid()) {
2355  DeclContext *DC = computeDeclContext(*SS, true);
2356  CurDecl = dyn_cast_or_null<CXXRecordDecl>(DC);
2357  } else
2358  CurDecl = dyn_cast_or_null<CXXRecordDecl>(CurContext);
2359 
2360  if (CurDecl && CurDecl->getIdentifier() && II != CurDecl->getIdentifier() &&
2361  3 * II->getName().edit_distance(CurDecl->getIdentifier()->getName())
2362  < II->getLength()) {
2363  II = CurDecl->getIdentifier();
2364  return true;
2365  }
2366 
2367  return false;
2368 }
2369 
2370 /// Determine whether the given class is a base class of the given
2371 /// class, including looking at dependent bases.
2372 static bool findCircularInheritance(const CXXRecordDecl *Class,
2373  const CXXRecordDecl *Current) {
2375 
2376  Class = Class->getCanonicalDecl();
2377  while (true) {
2378  for (const auto &I : Current->bases()) {
2379  CXXRecordDecl *Base = I.getType()->getAsCXXRecordDecl();
2380  if (!Base)
2381  continue;
2382 
2383  Base = Base->getDefinition();
2384  if (!Base)
2385  continue;
2386 
2387  if (Base->getCanonicalDecl() == Class)
2388  return true;
2389 
2390  Queue.push_back(Base);
2391  }
2392 
2393  if (Queue.empty())
2394  return false;
2395 
2396  Current = Queue.pop_back_val();
2397  }
2398 
2399  return false;
2400 }
2401 
2402 /// Check the validity of a C++ base class specifier.
2403 ///
2404 /// \returns a new CXXBaseSpecifier if well-formed, emits diagnostics
2405 /// and returns NULL otherwise.
2408  SourceRange SpecifierRange,
2409  bool Virtual, AccessSpecifier Access,
2410  TypeSourceInfo *TInfo,
2411  SourceLocation EllipsisLoc) {
2412  QualType BaseType = TInfo->getType();
2413 
2414  // C++ [class.union]p1:
2415  // A union shall not have base classes.
2416  if (Class->isUnion()) {
2417  Diag(Class->getLocation(), diag::err_base_clause_on_union)
2418  << SpecifierRange;
2419  return nullptr;
2420  }
2421 
2422  if (EllipsisLoc.isValid() &&
2424  Diag(EllipsisLoc, diag::err_pack_expansion_without_parameter_packs)
2425  << TInfo->getTypeLoc().getSourceRange();
2426  EllipsisLoc = SourceLocation();
2427  }
2428 
2429  SourceLocation BaseLoc = TInfo->getTypeLoc().getBeginLoc();
2430 
2431  if (BaseType->isDependentType()) {
2432  // Make sure that we don't have circular inheritance among our dependent
2433  // bases. For non-dependent bases, the check for completeness below handles
2434  // this.
2435  if (CXXRecordDecl *BaseDecl = BaseType->getAsCXXRecordDecl()) {
2436  if (BaseDecl->getCanonicalDecl() == Class->getCanonicalDecl() ||
2437  ((BaseDecl = BaseDecl->getDefinition()) &&
2438  findCircularInheritance(Class, BaseDecl))) {
2439  Diag(BaseLoc, diag::err_circular_inheritance)
2440  << BaseType << Context.getTypeDeclType(Class);
2441 
2442  if (BaseDecl->getCanonicalDecl() != Class->getCanonicalDecl())
2443  Diag(BaseDecl->getLocation(), diag::note_previous_decl)
2444  << BaseType;
2445 
2446  return nullptr;
2447  }
2448  }
2449 
2450  return new (Context) CXXBaseSpecifier(SpecifierRange, Virtual,
2451  Class->getTagKind() == TTK_Class,
2452  Access, TInfo, EllipsisLoc);
2453  }
2454 
2455  // Base specifiers must be record types.
2456  if (!BaseType->isRecordType()) {
2457  Diag(BaseLoc, diag::err_base_must_be_class) << SpecifierRange;
2458  return nullptr;
2459  }
2460 
2461  // C++ [class.union]p1:
2462  // A union shall not be used as a base class.
2463  if (BaseType->isUnionType()) {
2464  Diag(BaseLoc, diag::err_union_as_base_class) << SpecifierRange;
2465  return nullptr;
2466  }
2467 
2468  // For the MS ABI, propagate DLL attributes to base class templates.
2469  if (Context.getTargetInfo().getCXXABI().isMicrosoft()) {
2470  if (Attr *ClassAttr = getDLLAttr(Class)) {
2471  if (auto *BaseTemplate = dyn_cast_or_null<ClassTemplateSpecializationDecl>(
2472  BaseType->getAsCXXRecordDecl())) {
2473  propagateDLLAttrToBaseClassTemplate(Class, ClassAttr, BaseTemplate,
2474  BaseLoc);
2475  }
2476  }
2477  }
2478 
2479  // C++ [class.derived]p2:
2480  // The class-name in a base-specifier shall not be an incompletely
2481  // defined class.
2482  if (RequireCompleteType(BaseLoc, BaseType,
2483  diag::err_incomplete_base_class, SpecifierRange)) {
2484  Class->setInvalidDecl();
2485  return nullptr;
2486  }
2487 
2488  // If the base class is polymorphic or isn't empty, the new one is/isn't, too.
2489  RecordDecl *BaseDecl = BaseType->castAs<RecordType>()->getDecl();
2490  assert(BaseDecl && "Record type has no declaration");
2491  BaseDecl = BaseDecl->getDefinition();
2492  assert(BaseDecl && "Base type is not incomplete, but has no definition");
2493  CXXRecordDecl *CXXBaseDecl = cast<CXXRecordDecl>(BaseDecl);
2494  assert(CXXBaseDecl && "Base type is not a C++ type");
2495 
2496  // Microsoft docs say:
2497  // "If a base-class has a code_seg attribute, derived classes must have the
2498  // same attribute."
2499  const auto *BaseCSA = CXXBaseDecl->getAttr<CodeSegAttr>();
2500  const auto *DerivedCSA = Class->getAttr<CodeSegAttr>();
2501  if ((DerivedCSA || BaseCSA) &&
2502  (!BaseCSA || !DerivedCSA || BaseCSA->getName() != DerivedCSA->getName())) {
2503  Diag(Class->getLocation(), diag::err_mismatched_code_seg_base);
2504  Diag(CXXBaseDecl->getLocation(), diag::note_base_class_specified_here)
2505  << CXXBaseDecl;
2506  return nullptr;
2507  }
2508 
2509  // A class which contains a flexible array member is not suitable for use as a
2510  // base class:
2511  // - If the layout determines that a base comes before another base,
2512  // the flexible array member would index into the subsequent base.
2513  // - If the layout determines that base comes before the derived class,
2514  // the flexible array member would index into the derived class.
2515  if (CXXBaseDecl->hasFlexibleArrayMember()) {
2516  Diag(BaseLoc, diag::err_base_class_has_flexible_array_member)
2517  << CXXBaseDecl->getDeclName();
2518  return nullptr;
2519  }
2520 
2521  // C++ [class]p3:
2522  // If a class is marked final and it appears as a base-type-specifier in
2523  // base-clause, the program is ill-formed.
2524  if (FinalAttr *FA = CXXBaseDecl->getAttr<FinalAttr>()) {
2525  Diag(BaseLoc, diag::err_class_marked_final_used_as_base)
2526  << CXXBaseDecl->getDeclName()
2527  << FA->isSpelledAsSealed();
2528  Diag(CXXBaseDecl->getLocation(), diag::note_entity_declared_at)
2529  << CXXBaseDecl->getDeclName() << FA->getRange();
2530  return nullptr;
2531  }
2532 
2533  if (BaseDecl->isInvalidDecl())
2534  Class->setInvalidDecl();
2535 
2536  // Create the base specifier.
2537  return new (Context) CXXBaseSpecifier(SpecifierRange, Virtual,
2538  Class->getTagKind() == TTK_Class,
2539  Access, TInfo, EllipsisLoc);
2540 }
2541 
2542 /// ActOnBaseSpecifier - Parsed a base specifier. A base specifier is
2543 /// one entry in the base class list of a class specifier, for
2544 /// example:
2545 /// class foo : public bar, virtual private baz {
2546 /// 'public bar' and 'virtual private baz' are each base-specifiers.
2547 BaseResult
2548 Sema::ActOnBaseSpecifier(Decl *classdecl, SourceRange SpecifierRange,
2549  ParsedAttributes &Attributes,
2550  bool Virtual, AccessSpecifier Access,
2551  ParsedType basetype, SourceLocation BaseLoc,
2552  SourceLocation EllipsisLoc) {
2553  if (!classdecl)
2554  return true;
2555 
2556  AdjustDeclIfTemplate(classdecl);
2557  CXXRecordDecl *Class = dyn_cast<CXXRecordDecl>(classdecl);
2558  if (!Class)
2559  return true;
2560 
2561  // We haven't yet attached the base specifiers.
2562  Class->setIsParsingBaseSpecifiers();
2563 
2564  // We do not support any C++11 attributes on base-specifiers yet.
2565  // Diagnose any attributes we see.
2566  for (const ParsedAttr &AL : Attributes) {
2567  if (AL.isInvalid() || AL.getKind() == ParsedAttr::IgnoredAttribute)
2568  continue;
2569  Diag(AL.getLoc(), AL.getKind() == ParsedAttr::UnknownAttribute
2570  ? (unsigned)diag::warn_unknown_attribute_ignored
2571  : (unsigned)diag::err_base_specifier_attribute)
2572  << AL;
2573  }
2574 
2575  TypeSourceInfo *TInfo = nullptr;
2576  GetTypeFromParser(basetype, &TInfo);
2577 
2578  if (EllipsisLoc.isInvalid() &&
2579  DiagnoseUnexpandedParameterPack(SpecifierRange.getBegin(), TInfo,
2580  UPPC_BaseType))
2581  return true;
2582 
2583  if (CXXBaseSpecifier *BaseSpec = CheckBaseSpecifier(Class, SpecifierRange,
2584  Virtual, Access, TInfo,
2585  EllipsisLoc))
2586  return BaseSpec;
2587  else
2588  Class->setInvalidDecl();
2589 
2590  return true;
2591 }
2592 
2593 /// Use small set to collect indirect bases. As this is only used
2594 /// locally, there's no need to abstract the small size parameter.
2595 typedef llvm::SmallPtrSet<QualType, 4> IndirectBaseSet;
2596 
2597 /// Recursively add the bases of Type. Don't add Type itself.
2598 static void
2599 NoteIndirectBases(ASTContext &Context, IndirectBaseSet &Set,
2600  const QualType &Type)
2601 {
2602  // Even though the incoming type is a base, it might not be
2603  // a class -- it could be a template parm, for instance.
2604  if (auto Rec = Type->getAs<RecordType>()) {
2605  auto Decl = Rec->getAsCXXRecordDecl();
2606 
2607  // Iterate over its bases.
2608  for (const auto &BaseSpec : Decl->bases()) {
2609  QualType Base = Context.getCanonicalType(BaseSpec.getType())
2610  .getUnqualifiedType();
2611  if (Set.insert(Base).second)
2612  // If we've not already seen it, recurse.
2613  NoteIndirectBases(Context, Set, Base);
2614  }
2615  }
2616 }
2617 
2618 /// Performs the actual work of attaching the given base class
2619 /// specifiers to a C++ class.
2622  if (Bases.empty())
2623  return false;
2624 
2625  // Used to keep track of which base types we have already seen, so
2626  // that we can properly diagnose redundant direct base types. Note
2627  // that the key is always the unqualified canonical type of the base
2628  // class.
2629  std::map<QualType, CXXBaseSpecifier*, QualTypeOrdering> KnownBaseTypes;
2630 
2631  // Used to track indirect bases so we can see if a direct base is
2632  // ambiguous.
2633  IndirectBaseSet IndirectBaseTypes;
2634 
2635  // Copy non-redundant base specifiers into permanent storage.
2636  unsigned NumGoodBases = 0;
2637  bool Invalid = false;
2638  for (unsigned idx = 0; idx < Bases.size(); ++idx) {
2639  QualType NewBaseType
2640  = Context.getCanonicalType(Bases[idx]->getType());
2641  NewBaseType = NewBaseType.getLocalUnqualifiedType();
2642 
2643  CXXBaseSpecifier *&KnownBase = KnownBaseTypes[NewBaseType];
2644  if (KnownBase) {
2645  // C++ [class.mi]p3:
2646  // A class shall not be specified as a direct base class of a
2647  // derived class more than once.
2648  Diag(Bases[idx]->getBeginLoc(), diag::err_duplicate_base_class)
2649  << KnownBase->getType() << Bases[idx]->getSourceRange();
2650 
2651  // Delete the duplicate base class specifier; we're going to
2652  // overwrite its pointer later.
2653  Context.Deallocate(Bases[idx]);
2654 
2655  Invalid = true;
2656  } else {
2657  // Okay, add this new base class.
2658  KnownBase = Bases[idx];
2659  Bases[NumGoodBases++] = Bases[idx];
2660 
2661  // Note this base's direct & indirect bases, if there could be ambiguity.
2662  if (Bases.size() > 1)
2663  NoteIndirectBases(Context, IndirectBaseTypes, NewBaseType);
2664 
2665  if (const RecordType *Record = NewBaseType->getAs<RecordType>()) {
2666  const CXXRecordDecl *RD = cast<CXXRecordDecl>(Record->getDecl());
2667  if (Class->isInterface() &&
2668  (!RD->isInterfaceLike() ||
2669  KnownBase->getAccessSpecifier() != AS_public)) {
2670  // The Microsoft extension __interface does not permit bases that
2671  // are not themselves public interfaces.
2672  Diag(KnownBase->getBeginLoc(), diag::err_invalid_base_in_interface)
2673  << getRecordDiagFromTagKind(RD->getTagKind()) << RD
2674  << RD->getSourceRange();
2675  Invalid = true;
2676  }
2677  if (RD->hasAttr<WeakAttr>())
2678  Class->addAttr(WeakAttr::CreateImplicit(Context));
2679  }
2680  }
2681  }
2682 
2683  // Attach the remaining base class specifiers to the derived class.
2684  Class->setBases(Bases.data(), NumGoodBases);
2685 
2686  // Check that the only base classes that are duplicate are virtual.
2687  for (unsigned idx = 0; idx < NumGoodBases; ++idx) {
2688  // Check whether this direct base is inaccessible due to ambiguity.
2689  QualType BaseType = Bases[idx]->getType();
2690 
2691  // Skip all dependent types in templates being used as base specifiers.
2692  // Checks below assume that the base specifier is a CXXRecord.
2693  if (BaseType->isDependentType())
2694  continue;
2695 
2696  CanQualType CanonicalBase = Context.getCanonicalType(BaseType)
2697  .getUnqualifiedType();
2698 
2699  if (IndirectBaseTypes.count(CanonicalBase)) {
2700  CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/true,
2701  /*DetectVirtual=*/true);
2702  bool found
2703  = Class->isDerivedFrom(CanonicalBase->getAsCXXRecordDecl(), Paths);
2704  assert(found);
2705  (void)found;
2706 
2707  if (Paths.isAmbiguous(CanonicalBase))
2708  Diag(Bases[idx]->getBeginLoc(), diag::warn_inaccessible_base_class)
2709  << BaseType << getAmbiguousPathsDisplayString(Paths)
2710  << Bases[idx]->getSourceRange();
2711  else
2712  assert(Bases[idx]->isVirtual());
2713  }
2714 
2715  // Delete the base class specifier, since its data has been copied
2716  // into the CXXRecordDecl.
2717  Context.Deallocate(Bases[idx]);
2718  }
2719 
2720  return Invalid;
2721 }
2722 
2723 /// ActOnBaseSpecifiers - Attach the given base specifiers to the
2724 /// class, after checking whether there are any duplicate base
2725 /// classes.
2726 void Sema::ActOnBaseSpecifiers(Decl *ClassDecl,
2728  if (!ClassDecl || Bases.empty())
2729  return;
2730 
2731  AdjustDeclIfTemplate(ClassDecl);
2732  AttachBaseSpecifiers(cast<CXXRecordDecl>(ClassDecl), Bases);
2733 }
2734 
2735 /// Determine whether the type \p Derived is a C++ class that is
2736 /// derived from the type \p Base.
2738  if (!getLangOpts().CPlusPlus)
2739  return false;
2740 
2741  CXXRecordDecl *DerivedRD = Derived->getAsCXXRecordDecl();
2742  if (!DerivedRD)
2743  return false;
2744 
2745  CXXRecordDecl *BaseRD = Base->getAsCXXRecordDecl();
2746  if (!BaseRD)
2747  return false;
2748 
2749  // If either the base or the derived type is invalid, don't try to
2750  // check whether one is derived from the other.
2751  if (BaseRD->isInvalidDecl() || DerivedRD->isInvalidDecl())
2752  return false;
2753 
2754  // FIXME: In a modules build, do we need the entire path to be visible for us
2755  // to be able to use the inheritance relationship?
2756  if (!isCompleteType(Loc, Derived) && !DerivedRD->isBeingDefined())
2757  return false;
2758 
2759  return DerivedRD->isDerivedFrom(BaseRD);
2760 }
2761 
2762 /// Determine whether the type \p Derived is a C++ class that is
2763 /// derived from the type \p Base.
2765  CXXBasePaths &Paths) {
2766  if (!getLangOpts().CPlusPlus)
2767  return false;
2768 
2769  CXXRecordDecl *DerivedRD = Derived->getAsCXXRecordDecl();
2770  if (!DerivedRD)
2771  return false;
2772 
2773  CXXRecordDecl *BaseRD = Base->getAsCXXRecordDecl();
2774  if (!BaseRD)
2775  return false;
2776 
2777  if (!isCompleteType(Loc, Derived) && !DerivedRD->isBeingDefined())
2778  return false;
2779 
2780  return DerivedRD->isDerivedFrom(BaseRD, Paths);
2781 }
2782 
2783 static void BuildBasePathArray(const CXXBasePath &Path,
2784  CXXCastPath &BasePathArray) {
2785  // We first go backward and check if we have a virtual base.
2786  // FIXME: It would be better if CXXBasePath had the base specifier for
2787  // the nearest virtual base.
2788  unsigned Start = 0;
2789  for (unsigned I = Path.size(); I != 0; --I) {
2790  if (Path[I - 1].Base->isVirtual()) {
2791  Start = I - 1;
2792  break;
2793  }
2794  }
2795 
2796  // Now add all bases.
2797  for (unsigned I = Start, E = Path.size(); I != E; ++I)
2798  BasePathArray.push_back(const_cast<CXXBaseSpecifier*>(Path[I].Base));
2799 }
2800 
2801 
2803  CXXCastPath &BasePathArray) {
2804  assert(BasePathArray.empty() && "Base path array must be empty!");
2805  assert(Paths.isRecordingPaths() && "Must record paths!");
2806  return ::BuildBasePathArray(Paths.front(), BasePathArray);
2807 }
2808 /// CheckDerivedToBaseConversion - Check whether the Derived-to-Base
2809 /// conversion (where Derived and Base are class types) is
2810 /// well-formed, meaning that the conversion is unambiguous (and
2811 /// that all of the base classes are accessible). Returns true
2812 /// and emits a diagnostic if the code is ill-formed, returns false
2813 /// otherwise. Loc is the location where this routine should point to
2814 /// if there is an error, and Range is the source range to highlight
2815 /// if there is an error.
2816 ///
2817 /// If either InaccessibleBaseID or AmbigiousBaseConvID are 0, then the
2818 /// diagnostic for the respective type of error will be suppressed, but the
2819 /// check for ill-formed code will still be performed.
2820 bool
2822  unsigned InaccessibleBaseID,
2823  unsigned AmbigiousBaseConvID,
2824  SourceLocation Loc, SourceRange Range,
2825  DeclarationName Name,
2826  CXXCastPath *BasePath,
2827  bool IgnoreAccess) {
2828  // First, determine whether the path from Derived to Base is
2829  // ambiguous. This is slightly more expensive than checking whether
2830  // the Derived to Base conversion exists, because here we need to
2831  // explore multiple paths to determine if there is an ambiguity.
2832  CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/true,
2833  /*DetectVirtual=*/false);
2834  bool DerivationOkay = IsDerivedFrom(Loc, Derived, Base, Paths);
2835  if (!DerivationOkay)
2836  return true;
2837 
2838  const CXXBasePath *Path = nullptr;
2839  if (!Paths.isAmbiguous(Context.getCanonicalType(Base).getUnqualifiedType()))
2840  Path = &Paths.front();
2841 
2842  // For MSVC compatibility, check if Derived directly inherits from Base. Clang
2843  // warns about this hierarchy under -Winaccessible-base, but MSVC allows the
2844  // user to access such bases.
2845  if (!Path && getLangOpts().MSVCCompat) {
2846  for (const CXXBasePath &PossiblePath : Paths) {
2847  if (PossiblePath.size() == 1) {
2848  Path = &PossiblePath;
2849  if (AmbigiousBaseConvID)
2850  Diag(Loc, diag::ext_ms_ambiguous_direct_base)
2851  << Base << Derived << Range;
2852  break;
2853  }
2854  }
2855  }
2856 
2857  if (Path) {
2858  if (!IgnoreAccess) {
2859  // Check that the base class can be accessed.
2860  switch (
2861  CheckBaseClassAccess(Loc, Base, Derived, *Path, InaccessibleBaseID)) {
2862  case AR_inaccessible:
2863  return true;
2864  case AR_accessible:
2865  case AR_dependent:
2866  case AR_delayed:
2867  break;
2868  }
2869  }
2870 
2871  // Build a base path if necessary.
2872  if (BasePath)
2873  ::BuildBasePathArray(*Path, *BasePath);
2874  return false;
2875  }
2876 
2877  if (AmbigiousBaseConvID) {
2878  // We know that the derived-to-base conversion is ambiguous, and
2879  // we're going to produce a diagnostic. Perform the derived-to-base
2880  // search just one more time to compute all of the possible paths so
2881  // that we can print them out. This is more expensive than any of
2882  // the previous derived-to-base checks we've done, but at this point
2883  // performance isn't as much of an issue.
2884  Paths.clear();
2885  Paths.setRecordingPaths(true);
2886  bool StillOkay = IsDerivedFrom(Loc, Derived, Base, Paths);
2887  assert(StillOkay && "Can only be used with a derived-to-base conversion");
2888  (void)StillOkay;
2889 
2890  // Build up a textual representation of the ambiguous paths, e.g.,
2891  // D -> B -> A, that will be used to illustrate the ambiguous
2892  // conversions in the diagnostic. We only print one of the paths
2893  // to each base class subobject.
2894  std::string PathDisplayStr = getAmbiguousPathsDisplayString(Paths);
2895 
2896  Diag(Loc, AmbigiousBaseConvID)
2897  << Derived << Base << PathDisplayStr << Range << Name;
2898  }
2899  return true;
2900 }
2901 
2902 bool
2904  SourceLocation Loc, SourceRange Range,
2905  CXXCastPath *BasePath,
2906  bool IgnoreAccess) {
2907  return CheckDerivedToBaseConversion(
2908  Derived, Base, diag::err_upcast_to_inaccessible_base,
2909  diag::err_ambiguous_derived_to_base_conv, Loc, Range, DeclarationName(),
2910  BasePath, IgnoreAccess);
2911 }
2912 
2913 
2914 /// Builds a string representing ambiguous paths from a
2915 /// specific derived class to different subobjects of the same base
2916 /// class.
2917 ///
2918 /// This function builds a string that can be used in error messages
2919 /// to show the different paths that one can take through the
2920 /// inheritance hierarchy to go from the derived class to different
2921 /// subobjects of a base class. The result looks something like this:
2922 /// @code
2923 /// struct D -> struct B -> struct A
2924 /// struct D -> struct C -> struct A
2925 /// @endcode
2927  std::string PathDisplayStr;
2928  std::set<unsigned> DisplayedPaths;
2929  for (CXXBasePaths::paths_iterator Path = Paths.begin();
2930  Path != Paths.end(); ++Path) {
2931  if (DisplayedPaths.insert(Path->back().SubobjectNumber).second) {
2932  // We haven't displayed a path to this particular base
2933  // class subobject yet.
2934  PathDisplayStr += "\n ";
2935  PathDisplayStr += Context.getTypeDeclType(Paths.getOrigin()).getAsString();
2936  for (CXXBasePath::const_iterator Element = Path->begin();
2937  Element != Path->end(); ++Element)
2938  PathDisplayStr += " -> " + Element->Base->getType().getAsString();
2939  }
2940  }
2941 
2942  return PathDisplayStr;
2943 }
2944 
2945 //===----------------------------------------------------------------------===//
2946 // C++ class member Handling
2947 //===----------------------------------------------------------------------===//
2948 
2949 /// ActOnAccessSpecifier - Parsed an access specifier followed by a colon.
2952  const ParsedAttributesView &Attrs) {
2953  assert(Access != AS_none && "Invalid kind for syntactic access specifier!");
2954  AccessSpecDecl *ASDecl = AccessSpecDecl::Create(Context, Access, CurContext,
2955  ASLoc, ColonLoc);
2956  CurContext->addHiddenDecl(ASDecl);
2957  return ProcessAccessDeclAttributeList(ASDecl, Attrs);
2958 }
2959 
2960 /// CheckOverrideControl - Check C++11 override control semantics.
2962  if (D->isInvalidDecl())
2963  return;
2964 
2965  // We only care about "override" and "final" declarations.
2966  if (!D->hasAttr<OverrideAttr>() && !D->hasAttr<FinalAttr>())
2967  return;
2968 
2969  CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(D);
2970 
2971  // We can't check dependent instance methods.
2972  if (MD && MD->isInstance() &&
2973  (MD->getParent()->hasAnyDependentBases() ||
2974  MD->getType()->isDependentType()))
2975  return;
2976 
2977  if (MD && !MD->isVirtual()) {
2978  // If we have a non-virtual method, check if if hides a virtual method.
2979  // (In that case, it's most likely the method has the wrong type.)
2980  SmallVector<CXXMethodDecl *, 8> OverloadedMethods;
2981  FindHiddenVirtualMethods(MD, OverloadedMethods);
2982 
2983  if (!OverloadedMethods.empty()) {
2984  if (OverrideAttr *OA = D->getAttr<OverrideAttr>()) {
2985  Diag(OA->getLocation(),
2986  diag::override_keyword_hides_virtual_member_function)
2987  << "override" << (OverloadedMethods.size() > 1);
2988  } else if (FinalAttr *FA = D->getAttr<FinalAttr>()) {
2989  Diag(FA->getLocation(),
2990  diag::override_keyword_hides_virtual_member_function)
2991  << (FA->isSpelledAsSealed() ? "sealed" : "final")
2992  << (OverloadedMethods.size() > 1);
2993  }
2994  NoteHiddenVirtualMethods(MD, OverloadedMethods);
2995  MD->setInvalidDecl();
2996  return;
2997  }
2998  // Fall through into the general case diagnostic.
2999  // FIXME: We might want to attempt typo correction here.
3000  }
3001 
3002  if (!MD || !MD->isVirtual()) {
3003  if (OverrideAttr *OA = D->getAttr<OverrideAttr>()) {
3004  Diag(OA->getLocation(),
3005  diag::override_keyword_only_allowed_on_virtual_member_functions)
3006  << "override" << FixItHint::CreateRemoval(OA->getLocation());
3007  D->dropAttr<OverrideAttr>();
3008  }
3009  if (FinalAttr *FA = D->getAttr<FinalAttr>()) {
3010  Diag(FA->getLocation(),
3011  diag::override_keyword_only_allowed_on_virtual_member_functions)
3012  << (FA->isSpelledAsSealed() ? "sealed" : "final")
3013  << FixItHint::CreateRemoval(FA->getLocation());
3014  D->dropAttr<FinalAttr>();
3015  }
3016  return;
3017  }
3018 
3019  // C++11 [class.virtual]p5:
3020  // If a function is marked with the virt-specifier override and
3021  // does not override a member function of a base class, the program is
3022  // ill-formed.
3023  bool HasOverriddenMethods = MD->size_overridden_methods() != 0;
3024  if (MD->hasAttr<OverrideAttr>() && !HasOverriddenMethods)
3025  Diag(MD->getLocation(), diag::err_function_marked_override_not_overriding)
3026  << MD->getDeclName();
3027 }
3028 
3030  if (D->isInvalidDecl() || D->hasAttr<OverrideAttr>())
3031  return;
3032  CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(D);
3033  if (!MD || MD->isImplicit() || MD->hasAttr<FinalAttr>())
3034  return;
3035 
3036  SourceLocation Loc = MD->getLocation();
3037  SourceLocation SpellingLoc = Loc;
3038  if (getSourceManager().isMacroArgExpansion(Loc))
3039  SpellingLoc = getSourceManager().getImmediateExpansionRange(Loc).getBegin();
3040  SpellingLoc = getSourceManager().getSpellingLoc(SpellingLoc);
3041  if (SpellingLoc.isValid() && getSourceManager().isInSystemHeader(SpellingLoc))
3042  return;
3043 
3044  if (MD->size_overridden_methods() > 0) {
3045  unsigned DiagID = isa<CXXDestructorDecl>(MD)
3046  ? diag::warn_destructor_marked_not_override_overriding
3047  : diag::warn_function_marked_not_override_overriding;
3048  Diag(MD->getLocation(), DiagID) << MD->getDeclName();
3049  const CXXMethodDecl *OMD = *MD->begin_overridden_methods();
3050  Diag(OMD->getLocation(), diag::note_overridden_virtual_function);
3051  }
3052 }
3053 
3054 /// CheckIfOverriddenFunctionIsMarkedFinal - Checks whether a virtual member
3055 /// function overrides a virtual member function marked 'final', according to
3056 /// C++11 [class.virtual]p4.
3058  const CXXMethodDecl *Old) {
3059  FinalAttr *FA = Old->getAttr<FinalAttr>();
3060  if (!FA)
3061  return false;
3062 
3063  Diag(New->getLocation(), diag::err_final_function_overridden)
3064  << New->getDeclName()
3065  << FA->isSpelledAsSealed();
3066  Diag(Old->getLocation(), diag::note_overridden_virtual_function);
3067  return true;
3068 }
3069 
3070 static bool InitializationHasSideEffects(const FieldDecl &FD) {
3071  const Type *T = FD.getType()->getBaseElementTypeUnsafe();
3072  // FIXME: Destruction of ObjC lifetime types has side-effects.
3073  if (const CXXRecordDecl *RD = T->getAsCXXRecordDecl())
3074  return !RD->isCompleteDefinition() ||
3075  !RD->hasTrivialDefaultConstructor() ||
3076  !RD->hasTrivialDestructor();
3077  return false;
3078 }
3079 
3082  llvm::find_if(list, [](const ParsedAttr &AL) {
3083  return AL.isDeclspecPropertyAttribute();
3084  });
3085  if (Itr != list.end())
3086  return &*Itr;
3087  return nullptr;
3088 }
3089 
3090 // Check if there is a field shadowing.
3091 void Sema::CheckShadowInheritedFields(const SourceLocation &Loc,
3092  DeclarationName FieldName,
3093  const CXXRecordDecl *RD,
3094  bool DeclIsField) {
3095  if (Diags.isIgnored(diag::warn_shadow_field, Loc))
3096  return;
3097 
3098  // To record a shadowed field in a base
3099  std::map<CXXRecordDecl*, NamedDecl*> Bases;
3100  auto FieldShadowed = [&](const CXXBaseSpecifier *Specifier,
3101  CXXBasePath &Path) {
3102  const auto Base = Specifier->getType()->getAsCXXRecordDecl();
3103  // Record an ambiguous path directly
3104  if (Bases.find(Base) != Bases.end())
3105  return true;
3106  for (const auto Field : Base->lookup(FieldName)) {
3107  if ((isa<FieldDecl>(Field) || isa<IndirectFieldDecl>(Field)) &&
3108  Field->getAccess() != AS_private) {
3109  assert(Field->getAccess() != AS_none);
3110  assert(Bases.find(Base) == Bases.end());
3111  Bases[Base] = Field;
3112  return true;
3113  }
3114  }
3115  return false;
3116  };
3117 
3118  CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/true,
3119  /*DetectVirtual=*/true);
3120  if (!RD->lookupInBases(FieldShadowed, Paths))
3121  return;
3122 
3123  for (const auto &P : Paths) {
3124  auto Base = P.back().Base->getType()->getAsCXXRecordDecl();
3125  auto It = Bases.find(Base);
3126  // Skip duplicated bases
3127  if (It == Bases.end())
3128  continue;
3129  auto BaseField = It->second;
3130  assert(BaseField->getAccess() != AS_private);
3131  if (AS_none !=
3132  CXXRecordDecl::MergeAccess(P.Access, BaseField->getAccess())) {
3133  Diag(Loc, diag::warn_shadow_field)
3134  << FieldName << RD << Base << DeclIsField;
3135  Diag(BaseField->getLocation(), diag::note_shadow_field);
3136  Bases.erase(It);
3137  }
3138  }
3139 }
3140 
3141 /// ActOnCXXMemberDeclarator - This is invoked when a C++ class member
3142 /// declarator is parsed. 'AS' is the access specifier, 'BW' specifies the
3143 /// bitfield width if there is one, 'InitExpr' specifies the initializer if
3144 /// one has been parsed, and 'InitStyle' is set if an in-class initializer is
3145 /// present (but parsing it has been deferred).
3146 NamedDecl *
3148  MultiTemplateParamsArg TemplateParameterLists,
3149  Expr *BW, const VirtSpecifiers &VS,
3150  InClassInitStyle InitStyle) {
3151  const DeclSpec &DS = D.getDeclSpec();
3152  DeclarationNameInfo NameInfo = GetNameForDeclarator(D);
3153  DeclarationName Name = NameInfo.getName();
3154  SourceLocation Loc = NameInfo.getLoc();
3155 
3156  // For anonymous bitfields, the location should point to the type.
3157  if (Loc.isInvalid())
3158  Loc = D.getBeginLoc();
3159 
3160  Expr *BitWidth = static_cast<Expr*>(BW);
3161 
3162  assert(isa<CXXRecordDecl>(CurContext));
3163  assert(!DS.isFriendSpecified());
3164 
3165  bool isFunc = D.isDeclarationOfFunction();
3166  const ParsedAttr *MSPropertyAttr =
3168 
3169  if (cast<CXXRecordDecl>(CurContext)->isInterface()) {
3170  // The Microsoft extension __interface only permits public member functions
3171  // and prohibits constructors, destructors, operators, non-public member
3172  // functions, static methods and data members.
3173  unsigned InvalidDecl;
3174  bool ShowDeclName = true;
3175  if (!isFunc &&
3176  (DS.getStorageClassSpec() == DeclSpec::SCS_typedef || MSPropertyAttr))
3177  InvalidDecl = 0;
3178  else if (!isFunc)
3179  InvalidDecl = 1;
3180  else if (AS != AS_public)
3181  InvalidDecl = 2;
3182  else if (DS.getStorageClassSpec() == DeclSpec::SCS_static)
3183  InvalidDecl = 3;
3184  else switch (Name.getNameKind()) {
3186  InvalidDecl = 4;
3187  ShowDeclName = false;
3188  break;
3189 
3191  InvalidDecl = 5;
3192  ShowDeclName = false;
3193  break;
3194 
3197  InvalidDecl = 6;
3198  break;
3199 
3200  default:
3201  InvalidDecl = 0;
3202  break;
3203  }
3204 
3205  if (InvalidDecl) {
3206  if (ShowDeclName)
3207  Diag(Loc, diag::err_invalid_member_in_interface)
3208  << (InvalidDecl-1) << Name;
3209  else
3210  Diag(Loc, diag::err_invalid_member_in_interface)
3211  << (InvalidDecl-1) << "";
3212  return nullptr;
3213  }
3214  }
3215 
3216  // C++ 9.2p6: A member shall not be declared to have automatic storage
3217  // duration (auto, register) or with the extern storage-class-specifier.
3218  // C++ 7.1.1p8: The mutable specifier can be applied only to names of class
3219  // data members and cannot be applied to names declared const or static,
3220  // and cannot be applied to reference members.
3221  switch (DS.getStorageClassSpec()) {
3223  case DeclSpec::SCS_typedef:
3224  case DeclSpec::SCS_static:
3225  break;
3226  case DeclSpec::SCS_mutable:
3227  if (isFunc) {
3228  Diag(DS.getStorageClassSpecLoc(), diag::err_mutable_function);
3229 
3230  // FIXME: It would be nicer if the keyword was ignored only for this
3231  // declarator. Otherwise we could get follow-up errors.
3233  }
3234  break;
3235  default:
3237  diag::err_storageclass_invalid_for_member);
3239  break;
3240  }
3241 
3242  bool isInstField = ((DS.getStorageClassSpec() == DeclSpec::SCS_unspecified ||
3244  !isFunc);
3245 
3246  if (DS.hasConstexprSpecifier() && isInstField) {
3248  Diag(DS.getConstexprSpecLoc(), diag::err_invalid_constexpr_member);
3249  SourceLocation ConstexprLoc = DS.getConstexprSpecLoc();
3250  if (InitStyle == ICIS_NoInit) {
3251  B << 0 << 0;
3253  B << FixItHint::CreateRemoval(ConstexprLoc);
3254  else {
3255  B << FixItHint::CreateReplacement(ConstexprLoc, "const");
3257  const char *PrevSpec;
3258  unsigned DiagID;
3259  bool Failed = D.getMutableDeclSpec().SetTypeQual(
3260  DeclSpec::TQ_const, ConstexprLoc, PrevSpec, DiagID, getLangOpts());
3261  (void)Failed;
3262  assert(!Failed && "Making a constexpr member const shouldn't fail");
3263  }
3264  } else {
3265  B << 1;
3266  const char *PrevSpec;
3267  unsigned DiagID;
3269  *this, DeclSpec::SCS_static, ConstexprLoc, PrevSpec, DiagID,
3270  Context.getPrintingPolicy())) {
3271  assert(DS.getStorageClassSpec() == DeclSpec::SCS_mutable &&
3272  "This is the only DeclSpec that should fail to be applied");
3273  B << 1;
3274  } else {
3275  B << 0 << FixItHint::CreateInsertion(ConstexprLoc, "static ");
3276  isInstField = false;
3277  }
3278  }
3279  }
3280 
3281  NamedDecl *Member;
3282  if (isInstField) {
3283  CXXScopeSpec &SS = D.getCXXScopeSpec();
3284 
3285  // Data members must have identifiers for names.
3286  if (!Name.isIdentifier()) {
3287  Diag(Loc, diag::err_bad_variable_name)
3288  << Name;
3289  return nullptr;
3290  }
3291 
3292  IdentifierInfo *II = Name.getAsIdentifierInfo();
3293 
3294  // Member field could not be with "template" keyword.
3295  // So TemplateParameterLists should be empty in this case.
3296  if (TemplateParameterLists.size()) {
3297  TemplateParameterList* TemplateParams = TemplateParameterLists[0];
3298  if (TemplateParams->size()) {
3299  // There is no such thing as a member field template.
3300  Diag(D.getIdentifierLoc(), diag::err_template_member)
3301  << II
3302  << SourceRange(TemplateParams->getTemplateLoc(),
3303  TemplateParams->getRAngleLoc());
3304  } else {
3305  // There is an extraneous 'template<>' for this member.
3306  Diag(TemplateParams->getTemplateLoc(),
3307  diag::err_template_member_noparams)
3308  << II
3309  << SourceRange(TemplateParams->getTemplateLoc(),
3310  TemplateParams->getRAngleLoc());
3311  }
3312  return nullptr;
3313  }
3314 
3315  if (SS.isSet() && !SS.isInvalid()) {
3316  // The user provided a superfluous scope specifier inside a class
3317  // definition:
3318  //
3319  // class X {
3320  // int X::member;
3321  // };
3322  if (DeclContext *DC = computeDeclContext(SS, false))
3323  diagnoseQualifiedDeclaration(SS, DC, Name, D.getIdentifierLoc(),
3324  D.getName().getKind() ==
3326  else
3327  Diag(D.getIdentifierLoc(), diag::err_member_qualification)
3328  << Name << SS.getRange();
3329 
3330  SS.clear();
3331  }
3332 
3333  if (MSPropertyAttr) {
3334  Member = HandleMSProperty(S, cast<CXXRecordDecl>(CurContext), Loc, D,
3335  BitWidth, InitStyle, AS, *MSPropertyAttr);
3336  if (!Member)
3337  return nullptr;
3338  isInstField = false;
3339  } else {
3340  Member = HandleField(S, cast<CXXRecordDecl>(CurContext), Loc, D,
3341  BitWidth, InitStyle, AS);
3342  if (!Member)
3343  return nullptr;
3344  }
3345 
3346  CheckShadowInheritedFields(Loc, Name, cast<CXXRecordDecl>(CurContext));
3347  } else {
3348  Member = HandleDeclarator(S, D, TemplateParameterLists);
3349  if (!Member)
3350  return nullptr;
3351 
3352  // Non-instance-fields can't have a bitfield.
3353  if (BitWidth) {
3354  if (Member->isInvalidDecl()) {
3355  // don't emit another diagnostic.
3356  } else if (isa<VarDecl>(Member) || isa<VarTemplateDecl>(Member)) {
3357  // C++ 9.6p3: A bit-field shall not be a static member.
3358  // "static member 'A' cannot be a bit-field"
3359  Diag(Loc, diag::err_static_not_bitfield)
3360  << Name << BitWidth->getSourceRange();
3361  } else if (isa<TypedefDecl>(Member)) {
3362  // "typedef member 'x' cannot be a bit-field"
3363  Diag(Loc, diag::err_typedef_not_bitfield)
3364  << Name << BitWidth->getSourceRange();
3365  } else {
3366  // A function typedef ("typedef int f(); f a;").
3367  // C++ 9.6p3: A bit-field shall have integral or enumeration type.
3368  Diag(Loc, diag::err_not_integral_type_bitfield)
3369  << Name << cast<ValueDecl>(Member)->getType()
3370  << BitWidth->getSourceRange();
3371  }
3372 
3373  BitWidth = nullptr;
3374  Member->setInvalidDecl();
3375  }
3376 
3377  NamedDecl *NonTemplateMember = Member;
3378  if (FunctionTemplateDecl *FunTmpl = dyn_cast<FunctionTemplateDecl>(Member))
3379  NonTemplateMember = FunTmpl->getTemplatedDecl();
3380  else if (VarTemplateDecl *VarTmpl = dyn_cast<VarTemplateDecl>(Member))
3381  NonTemplateMember = VarTmpl->getTemplatedDecl();
3382 
3383  Member->setAccess(AS);
3384 
3385  // If we have declared a member function template or static data member
3386  // template, set the access of the templated declaration as well.
3387  if (NonTemplateMember != Member)
3388  NonTemplateMember->setAccess(AS);
3389 
3390  // C++ [temp.deduct.guide]p3:
3391  // A deduction guide [...] for a member class template [shall be
3392  // declared] with the same access [as the template].
3393  if (auto *DG = dyn_cast<CXXDeductionGuideDecl>(NonTemplateMember)) {
3394  auto *TD = DG->getDeducedTemplate();
3395  // Access specifiers are only meaningful if both the template and the
3396  // deduction guide are from the same scope.
3397  if (AS != TD->getAccess() &&
3398  TD->getDeclContext()->getRedeclContext()->Equals(
3399  DG->getDeclContext()->getRedeclContext())) {
3400  Diag(DG->getBeginLoc(), diag::err_deduction_guide_wrong_access);
3401  Diag(TD->getBeginLoc(), diag::note_deduction_guide_template_access)
3402  << TD->getAccess();
3403  const AccessSpecDecl *LastAccessSpec = nullptr;
3404  for (const auto *D : cast<CXXRecordDecl>(CurContext)->decls()) {
3405  if (const auto *AccessSpec = dyn_cast<AccessSpecDecl>(D))
3406  LastAccessSpec = AccessSpec;
3407  }
3408  assert(LastAccessSpec && "differing access with no access specifier");
3409  Diag(LastAccessSpec->getBeginLoc(), diag::note_deduction_guide_access)
3410  << AS;
3411  }
3412  }
3413  }
3414 
3415  if (VS.isOverrideSpecified())
3416  Member->addAttr(OverrideAttr::Create(Context, VS.getOverrideLoc(),
3418  if (VS.isFinalSpecified())
3419  Member->addAttr(FinalAttr::Create(
3421  static_cast<FinalAttr::Spelling>(VS.isFinalSpelledSealed())));
3422 
3423  if (VS.getLastLocation().isValid()) {
3424  // Update the end location of a method that has a virt-specifiers.
3425  if (CXXMethodDecl *MD = dyn_cast_or_null<CXXMethodDecl>(Member))
3426  MD->setRangeEnd(VS.getLastLocation());
3427  }
3428 
3429  CheckOverrideControl(Member);
3430 
3431  assert((Name || isInstField) && "No identifier for non-field ?");
3432 
3433  if (isInstField) {
3434  FieldDecl *FD = cast<FieldDecl>(Member);
3435  FieldCollector->Add(FD);
3436 
3437  if (!Diags.isIgnored(diag::warn_unused_private_field, FD->getLocation())) {
3438  // Remember all explicit private FieldDecls that have a name, no side
3439  // effects and are not part of a dependent type declaration.
3440  if (!FD->isImplicit() && FD->getDeclName() &&
3441  FD->getAccess() == AS_private &&
3442  !FD->hasAttr<UnusedAttr>() &&
3443  !FD->getParent()->isDependentContext() &&
3445  UnusedPrivateFields.insert(FD);
3446  }
3447  }
3448 
3449  return Member;
3450 }
3451 
3452 namespace {
3453  class UninitializedFieldVisitor
3454  : public EvaluatedExprVisitor<UninitializedFieldVisitor> {
3455  Sema &S;
3456  // List of Decls to generate a warning on. Also remove Decls that become
3457  // initialized.
3458  llvm::SmallPtrSetImpl<ValueDecl*> &Decls;
3459  // List of base classes of the record. Classes are removed after their
3460  // initializers.
3461  llvm::SmallPtrSetImpl<QualType> &BaseClasses;
3462  // Vector of decls to be removed from the Decl set prior to visiting the
3463  // nodes. These Decls may have been initialized in the prior initializer.
3464  llvm::SmallVector<ValueDecl*, 4> DeclsToRemove;
3465  // If non-null, add a note to the warning pointing back to the constructor.
3466  const CXXConstructorDecl *Constructor;
3467  // Variables to hold state when processing an initializer list. When
3468  // InitList is true, special case initialization of FieldDecls matching
3469  // InitListFieldDecl.
3470  bool InitList;
3471  FieldDecl *InitListFieldDecl;
3472  llvm::SmallVector<unsigned, 4> InitFieldIndex;
3473 
3474  public:
3476  UninitializedFieldVisitor(Sema &S,
3477  llvm::SmallPtrSetImpl<ValueDecl*> &Decls,
3478  llvm::SmallPtrSetImpl<QualType> &BaseClasses)
3479  : Inherited(S.Context), S(S), Decls(Decls), BaseClasses(BaseClasses),
3480  Constructor(nullptr), InitList(false), InitListFieldDecl(nullptr) {}
3481 
3482  // Returns true if the use of ME is not an uninitialized use.
3483  bool IsInitListMemberExprInitialized(MemberExpr *ME,
3484  bool CheckReferenceOnly) {
3486  bool ReferenceField = false;
3487  while (ME) {
3488  FieldDecl *FD = dyn_cast<FieldDecl>(ME->getMemberDecl());
3489  if (!FD)
3490  return false;
3491  Fields.push_back(FD);
3492  if (FD->getType()->isReferenceType())
3493  ReferenceField = true;
3494  ME = dyn_cast<MemberExpr>(ME->getBase()->IgnoreParenImpCasts());
3495  }
3496 
3497  // Binding a reference to an uninitialized field is not an
3498  // uninitialized use.
3499  if (CheckReferenceOnly && !ReferenceField)
3500  return true;
3501 
3502  llvm::SmallVector<unsigned, 4> UsedFieldIndex;
3503  // Discard the first field since it is the field decl that is being
3504  // initialized.
3505  for (auto I = Fields.rbegin() + 1, E = Fields.rend(); I != E; ++I) {
3506  UsedFieldIndex.push_back((*I)->getFieldIndex());
3507  }
3508 
3509  for (auto UsedIter = UsedFieldIndex.begin(),
3510  UsedEnd = UsedFieldIndex.end(),
3511  OrigIter = InitFieldIndex.begin(),
3512  OrigEnd = InitFieldIndex.end();
3513  UsedIter != UsedEnd && OrigIter != OrigEnd; ++UsedIter, ++OrigIter) {
3514  if (*UsedIter < *OrigIter)
3515  return true;
3516  if (*UsedIter > *OrigIter)
3517  break;
3518  }
3519 
3520  return false;
3521  }
3522 
3523  void HandleMemberExpr(MemberExpr *ME, bool CheckReferenceOnly,
3524  bool AddressOf) {
3525  if (isa<EnumConstantDecl>(ME->getMemberDecl()))
3526  return;
3527 
3528  // FieldME is the inner-most MemberExpr that is not an anonymous struct
3529  // or union.
3530  MemberExpr *FieldME = ME;
3531 
3532  bool AllPODFields = FieldME->getType().isPODType(S.Context);
3533 
3534  Expr *Base = ME;
3535  while (MemberExpr *SubME =
3536  dyn_cast<MemberExpr>(Base->IgnoreParenImpCasts())) {
3537 
3538  if (isa<VarDecl>(SubME->getMemberDecl()))
3539  return;
3540 
3541  if (FieldDecl *FD = dyn_cast<FieldDecl>(SubME->getMemberDecl()))
3542  if (!FD->isAnonymousStructOrUnion())
3543  FieldME = SubME;
3544 
3545  if (!FieldME->getType().isPODType(S.Context))
3546  AllPODFields = false;
3547 
3548  Base = SubME->getBase();
3549  }
3550 
3551  if (!isa<CXXThisExpr>(Base->IgnoreParenImpCasts()))
3552  return;
3553 
3554  if (AddressOf && AllPODFields)
3555  return;
3556 
3557  ValueDecl* FoundVD = FieldME->getMemberDecl();
3558 
3559  if (ImplicitCastExpr *BaseCast = dyn_cast<ImplicitCastExpr>(Base)) {
3560  while (isa<ImplicitCastExpr>(BaseCast->getSubExpr())) {
3561  BaseCast = cast<ImplicitCastExpr>(BaseCast->getSubExpr());
3562  }
3563 
3564  if (BaseCast->getCastKind() == CK_UncheckedDerivedToBase) {
3565  QualType T = BaseCast->getType();
3566  if (T->isPointerType() &&
3567  BaseClasses.count(T->getPointeeType())) {
3568  S.Diag(FieldME->getExprLoc(), diag::warn_base_class_is_uninit)
3569  << T->getPointeeType() << FoundVD;
3570  }
3571  }
3572  }
3573 
3574  if (!Decls.count(FoundVD))
3575  return;
3576 
3577  const bool IsReference = FoundVD->getType()->isReferenceType();
3578 
3579  if (InitList && !AddressOf && FoundVD == InitListFieldDecl) {
3580  // Special checking for initializer lists.
3581  if (IsInitListMemberExprInitialized(ME, CheckReferenceOnly)) {
3582  return;
3583  }
3584  } else {
3585  // Prevent double warnings on use of unbounded references.
3586  if (CheckReferenceOnly && !IsReference)
3587  return;
3588  }
3589 
3590  unsigned diag = IsReference
3591  ? diag::warn_reference_field_is_uninit
3592  : diag::warn_field_is_uninit;
3593  S.Diag(FieldME->getExprLoc(), diag) << FoundVD;
3594  if (Constructor)
3595  S.Diag(Constructor->getLocation(),
3596  diag::note_uninit_in_this_constructor)
3597  << (Constructor->isDefaultConstructor() && Constructor->isImplicit());
3598 
3599  }
3600 
3601  void HandleValue(Expr *E, bool AddressOf) {
3602  E = E->IgnoreParens();
3603 
3604  if (MemberExpr *ME = dyn_cast<MemberExpr>(E)) {
3605  HandleMemberExpr(ME, false /*CheckReferenceOnly*/,
3606  AddressOf /*AddressOf*/);
3607  return;
3608  }
3609 
3610  if (ConditionalOperator *CO = dyn_cast<ConditionalOperator>(E)) {
3611  Visit(CO->getCond());
3612  HandleValue(CO->getTrueExpr(), AddressOf);
3613  HandleValue(CO->getFalseExpr(), AddressOf);
3614  return;
3615  }
3616 
3617  if (BinaryConditionalOperator *BCO =
3618  dyn_cast<BinaryConditionalOperator>(E)) {
3619  Visit(BCO->getCond());
3620  HandleValue(BCO->getFalseExpr(), AddressOf);
3621  return;
3622  }
3623 
3624  if (OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(E)) {
3625  HandleValue(OVE->getSourceExpr(), AddressOf);
3626  return;
3627  }
3628 
3629  if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) {
3630  switch (BO->getOpcode()) {
3631  default:
3632  break;
3633  case(BO_PtrMemD):
3634  case(BO_PtrMemI):
3635  HandleValue(BO->getLHS(), AddressOf);
3636  Visit(BO->getRHS());
3637  return;
3638  case(BO_Comma):
3639  Visit(BO->getLHS());
3640  HandleValue(BO->getRHS(), AddressOf);
3641  return;
3642  }
3643  }
3644 
3645  Visit(E);
3646  }
3647 
3648  void CheckInitListExpr(InitListExpr *ILE) {
3649  InitFieldIndex.push_back(0);
3650  for (auto Child : ILE->children()) {
3651  if (InitListExpr *SubList = dyn_cast<InitListExpr>(Child)) {
3652  CheckInitListExpr(SubList);
3653  } else {
3654  Visit(Child);
3655  }
3656  ++InitFieldIndex.back();
3657  }
3658  InitFieldIndex.pop_back();
3659  }
3660 
3661  void CheckInitializer(Expr *E, const CXXConstructorDecl *FieldConstructor,
3662  FieldDecl *Field, const Type *BaseClass) {
3663  // Remove Decls that may have been initialized in the previous
3664  // initializer.
3665  for (ValueDecl* VD : DeclsToRemove)
3666  Decls.erase(VD);
3667  DeclsToRemove.clear();
3668 
3669  Constructor = FieldConstructor;
3670  InitListExpr *ILE = dyn_cast<InitListExpr>(E);
3671 
3672  if (ILE && Field) {
3673  InitList = true;
3674  InitListFieldDecl = Field;
3675  InitFieldIndex.clear();
3676  CheckInitListExpr(ILE);
3677  } else {
3678  InitList = false;
3679  Visit(E);
3680  }
3681 
3682  if (Field)
3683  Decls.erase(Field);
3684  if (BaseClass)
3685  BaseClasses.erase(BaseClass->getCanonicalTypeInternal());
3686  }
3687 
3688  void VisitMemberExpr(MemberExpr *ME) {
3689  // All uses of unbounded reference fields will warn.
3690  HandleMemberExpr(ME, true /*CheckReferenceOnly*/, false /*AddressOf*/);
3691  }
3692 
3693  void VisitImplicitCastExpr(ImplicitCastExpr *E) {
3694  if (E->getCastKind() == CK_LValueToRValue) {
3695  HandleValue(E->getSubExpr(), false /*AddressOf*/);
3696  return;
3697  }
3698 
3699  Inherited::VisitImplicitCastExpr(E);
3700  }
3701 
3702  void VisitCXXConstructExpr(CXXConstructExpr *E) {
3703  if (E->getConstructor()->isCopyConstructor()) {
3704  Expr *ArgExpr = E->getArg(0);
3705  if (InitListExpr *ILE = dyn_cast<InitListExpr>(ArgExpr))
3706  if (ILE->getNumInits() == 1)
3707  ArgExpr = ILE->getInit(0);
3708  if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(ArgExpr))
3709  if (ICE->getCastKind() == CK_NoOp)
3710  ArgExpr = ICE->getSubExpr();
3711  HandleValue(ArgExpr, false /*AddressOf*/);
3712  return;
3713  }
3714  Inherited::VisitCXXConstructExpr(E);
3715  }
3716 
3717  void VisitCXXMemberCallExpr(CXXMemberCallExpr *E) {
3718  Expr *Callee = E->getCallee();
3719  if (isa<MemberExpr>(Callee)) {
3720  HandleValue(Callee, false /*AddressOf*/);
3721  for (auto Arg : E->arguments())
3722  Visit(Arg);
3723  return;
3724  }
3725 
3726  Inherited::VisitCXXMemberCallExpr(E);
3727  }
3728 
3729  void VisitCallExpr(CallExpr *E) {
3730  // Treat std::move as a use.
3731  if (E->isCallToStdMove()) {
3732  HandleValue(E->getArg(0), /*AddressOf=*/false);
3733  return;
3734  }
3735 
3736  Inherited::VisitCallExpr(E);
3737  }
3738 
3739  void VisitCXXOperatorCallExpr(CXXOperatorCallExpr *E) {
3740  Expr *Callee = E->getCallee();
3741 
3742  if (isa<UnresolvedLookupExpr>(Callee))
3743  return Inherited::VisitCXXOperatorCallExpr(E);
3744 
3745  Visit(Callee);
3746  for (auto Arg : E->arguments())
3747  HandleValue(Arg->IgnoreParenImpCasts(), false /*AddressOf*/);
3748  }
3749 
3750  void VisitBinaryOperator(BinaryOperator *E) {
3751  // If a field assignment is detected, remove the field from the
3752  // uninitiailized field set.
3753  if (E->getOpcode() == BO_Assign)
3754  if (MemberExpr *ME = dyn_cast<MemberExpr>(E->getLHS()))
3755  if (FieldDecl *FD = dyn_cast<FieldDecl>(ME->getMemberDecl()))
3756  if (!FD->getType()->isReferenceType())
3757  DeclsToRemove.push_back(FD);
3758 
3759  if (E->isCompoundAssignmentOp()) {
3760  HandleValue(E->getLHS(), false /*AddressOf*/);
3761  Visit(E->getRHS());
3762  return;
3763  }
3764 
3765  Inherited::VisitBinaryOperator(E);
3766  }
3767 
3768  void VisitUnaryOperator(UnaryOperator *E) {
3769  if (E->isIncrementDecrementOp()) {
3770  HandleValue(E->getSubExpr(), false /*AddressOf*/);
3771  return;
3772  }
3773  if (E->getOpcode() == UO_AddrOf) {
3774  if (MemberExpr *ME = dyn_cast<MemberExpr>(E->getSubExpr())) {
3775  HandleValue(ME->getBase(), true /*AddressOf*/);
3776  return;
3777  }
3778  }
3779 
3780  Inherited::VisitUnaryOperator(E);
3781  }
3782  };
3783 
3784  // Diagnose value-uses of fields to initialize themselves, e.g.
3785  // foo(foo)
3786  // where foo is not also a parameter to the constructor.
3787  // Also diagnose across field uninitialized use such as
3788  // x(y), y(x)
3789  // TODO: implement -Wuninitialized and fold this into that framework.
3790  static void DiagnoseUninitializedFields(
3791  Sema &SemaRef, const CXXConstructorDecl *Constructor) {
3792 
3793  if (SemaRef.getDiagnostics().isIgnored(diag::warn_field_is_uninit,
3794  Constructor->getLocation())) {
3795  return;
3796  }
3797 
3798  if (Constructor->isInvalidDecl())
3799  return;
3800 
3801  const CXXRecordDecl *RD = Constructor->getParent();
3802 
3803  if (RD->getDescribedClassTemplate())
3804  return;
3805 
3806  // Holds fields that are uninitialized.
3807  llvm::SmallPtrSet<ValueDecl*, 4> UninitializedFields;
3808 
3809  // At the beginning, all fields are uninitialized.
3810  for (auto *I : RD->decls()) {
3811  if (auto *FD = dyn_cast<FieldDecl>(I)) {
3812  UninitializedFields.insert(FD);
3813  } else if (auto *IFD = dyn_cast<IndirectFieldDecl>(I)) {
3814  UninitializedFields.insert(IFD->getAnonField());
3815  }
3816  }
3817 
3818  llvm::SmallPtrSet<QualType, 4> UninitializedBaseClasses;
3819  for (auto I : RD->bases())
3820  UninitializedBaseClasses.insert(I.getType().getCanonicalType());
3821 
3822  if (UninitializedFields.empty() && UninitializedBaseClasses.empty())
3823  return;
3824 
3825  UninitializedFieldVisitor UninitializedChecker(SemaRef,
3826  UninitializedFields,
3827  UninitializedBaseClasses);
3828 
3829  for (const auto *FieldInit : Constructor->inits()) {
3830  if (UninitializedFields.empty() && UninitializedBaseClasses.empty())
3831  break;
3832 
3833  Expr *InitExpr = FieldInit->getInit();
3834  if (!InitExpr)
3835  continue;
3836 
3838  dyn_cast<CXXDefaultInitExpr>(InitExpr)) {
3839  InitExpr = Default->getExpr();
3840  if (!InitExpr)
3841  continue;
3842  // In class initializers will point to the constructor.
3843  UninitializedChecker.CheckInitializer(InitExpr, Constructor,
3844  FieldInit->getAnyMember(),
3845  FieldInit->getBaseClass());
3846  } else {
3847  UninitializedChecker.CheckInitializer(InitExpr, nullptr,
3848  FieldInit->getAnyMember(),
3849  FieldInit->getBaseClass());
3850  }
3851  }
3852  }
3853 } // namespace
3854 
3855 /// Enter a new C++ default initializer scope. After calling this, the
3856 /// caller must call \ref ActOnFinishCXXInClassMemberInitializer, even if
3857 /// parsing or instantiating the initializer failed.
3859  // Create a synthetic function scope to represent the call to the constructor
3860  // that notionally surrounds a use of this initializer.
3861  PushFunctionScope();
3862 }
3863 
3864 /// This is invoked after parsing an in-class initializer for a
3865 /// non-static C++ class member, and after instantiating an in-class initializer
3866 /// in a class template. Such actions are deferred until the class is complete.
3868  SourceLocation InitLoc,
3869  Expr *InitExpr) {
3870  // Pop the notional constructor scope we created earlier.
3871  PopFunctionScopeInfo(nullptr, D);
3872 
3873  FieldDecl *FD = dyn_cast<FieldDecl>(D);
3874  assert((isa<MSPropertyDecl>(D) || FD->getInClassInitStyle() != ICIS_NoInit) &&
3875  "must set init style when field is created");
3876 
3877  if (!InitExpr) {
3878  D->setInvalidDecl();
3879  if (FD)
3881  return;
3882  }
3883 
3884  if (DiagnoseUnexpandedParameterPack(InitExpr, UPPC_Initializer)) {
3885  FD->setInvalidDecl();
3887  return;
3888  }
3889 
3890  ExprResult Init = InitExpr;
3891  if (!FD->getType()->isDependentType() && !InitExpr->isTypeDependent()) {
3892  InitializedEntity Entity =
3894  InitializationKind Kind =
3897  InitExpr->getBeginLoc(),
3898  InitExpr->getEndLoc())
3899  : InitializationKind::CreateCopy(InitExpr->getBeginLoc(), InitLoc);
3900  InitializationSequence Seq(*this, Entity, Kind, InitExpr);
3901  Init = Seq.Perform(*this, Entity, Kind, InitExpr);
3902  if (Init.isInvalid()) {
3903  FD->setInvalidDecl();
3904  return;
3905  }
3906  }
3907 
3908  // C++11 [class.base.init]p7:
3909  // The initialization of each base and member constitutes a
3910  // full-expression.
3911  Init = ActOnFinishFullExpr(Init.get(), InitLoc, /*DiscardedValue*/ false);
3912  if (Init.isInvalid()) {
3913  FD->setInvalidDecl();
3914  return;
3915  }
3916 
3917  InitExpr = Init.get();
3918 
3919  FD->setInClassInitializer(InitExpr);
3920 }
3921 
3922 /// Find the direct and/or virtual base specifiers that
3923 /// correspond to the given base type, for use in base initialization
3924 /// within a constructor.
3925 static bool FindBaseInitializer(Sema &SemaRef,
3926  CXXRecordDecl *ClassDecl,
3927  QualType BaseType,
3928  const CXXBaseSpecifier *&DirectBaseSpec,
3929  const CXXBaseSpecifier *&VirtualBaseSpec) {
3930  // First, check for a direct base class.
3931  DirectBaseSpec = nullptr;
3932  for (const auto &Base : ClassDecl->bases()) {
3933  if (SemaRef.Context.hasSameUnqualifiedType(BaseType, Base.getType())) {
3934  // We found a direct base of this type. That's what we're
3935  // initializing.
3936  DirectBaseSpec = &Base;
3937  break;
3938  }
3939  }
3940 
3941  // Check for a virtual base class.
3942  // FIXME: We might be able to short-circuit this if we know in advance that
3943  // there are no virtual bases.
3944  VirtualBaseSpec = nullptr;
3945  if (!DirectBaseSpec || !DirectBaseSpec->isVirtual()) {
3946  // We haven't found a base yet; search the class hierarchy for a
3947  // virtual base class.
3948  CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/true,
3949  /*DetectVirtual=*/false);
3950  if (SemaRef.IsDerivedFrom(ClassDecl->getLocation(),
3951  SemaRef.Context.getTypeDeclType(ClassDecl),
3952  BaseType, Paths)) {
3953  for (CXXBasePaths::paths_iterator Path = Paths.begin();
3954  Path != Paths.end(); ++Path) {
3955  if (Path->back().Base->isVirtual()) {
3956  VirtualBaseSpec = Path->back().Base;
3957  break;
3958  }
3959  }
3960  }
3961  }
3962 
3963  return DirectBaseSpec || VirtualBaseSpec;
3964 }
3965 
3966 /// Handle a C++ member initializer using braced-init-list syntax.
3968 Sema::ActOnMemInitializer(Decl *ConstructorD,
3969  Scope *S,
3970  CXXScopeSpec &SS,
3971  IdentifierInfo *MemberOrBase,
3972  ParsedType TemplateTypeTy,
3973  const DeclSpec &DS,
3974  SourceLocation IdLoc,
3975  Expr *InitList,
3976  SourceLocation EllipsisLoc) {
3977  return BuildMemInitializer(ConstructorD, S, SS, MemberOrBase, TemplateTypeTy,
3978  DS, IdLoc, InitList,
3979  EllipsisLoc);
3980 }
3981 
3982 /// Handle a C++ member initializer using parentheses syntax.
3984 Sema::ActOnMemInitializer(Decl *ConstructorD,
3985  Scope *S,
3986  CXXScopeSpec &SS,
3987  IdentifierInfo *MemberOrBase,
3988  ParsedType TemplateTypeTy,
3989  const DeclSpec &DS,
3990  SourceLocation IdLoc,
3991  SourceLocation LParenLoc,
3992  ArrayRef<Expr *> Args,
3993  SourceLocation RParenLoc,
3994  SourceLocation EllipsisLoc) {
3995  Expr *List = ParenListExpr::Create(Context, LParenLoc, Args, RParenLoc);
3996  return BuildMemInitializer(ConstructorD, S, SS, MemberOrBase, TemplateTypeTy,
3997  DS, IdLoc, List, EllipsisLoc);
3998 }
3999 
4000 namespace {
4001 
4002 // Callback to only accept typo corrections that can be a valid C++ member
4003 // intializer: either a non-static field member or a base class.
4004 class MemInitializerValidatorCCC final : public CorrectionCandidateCallback {
4005 public:
4006  explicit MemInitializerValidatorCCC(CXXRecordDecl *ClassDecl)
4007  : ClassDecl(ClassDecl) {}
4008 
4009  bool ValidateCandidate(const TypoCorrection &candidate) override {
4010  if (NamedDecl *ND = candidate.getCorrectionDecl()) {
4011  if (FieldDecl *Member = dyn_cast<FieldDecl>(ND))
4012  return Member->getDeclContext()->getRedeclContext()->Equals(ClassDecl);
4013  return isa<TypeDecl>(ND);
4014  }
4015  return false;
4016  }
4017 
4018  std::unique_ptr<CorrectionCandidateCallback> clone() override {
4019  return std::make_unique<MemInitializerValidatorCCC>(*this);
4020  }
4021 
4022 private:
4023  CXXRecordDecl *ClassDecl;
4024 };
4025 
4026 }
4027 
4028 ValueDecl *Sema::tryLookupCtorInitMemberDecl(CXXRecordDecl *ClassDecl,
4029  CXXScopeSpec &SS,
4030  ParsedType TemplateTypeTy,
4031  IdentifierInfo *MemberOrBase) {
4032  if (SS.getScopeRep() || TemplateTypeTy)
4033  return nullptr;
4034  DeclContext::lookup_result Result = ClassDecl->lookup(MemberOrBase);
4035  if (Result.empty())
4036  return nullptr;
4037  ValueDecl *Member;
4038  if ((Member = dyn_cast<FieldDecl>(Result.front())) ||
4039  (Member = dyn_cast<IndirectFieldDecl>(Result.front())))
4040  return Member;
4041  return nullptr;
4042 }
4043 
4044 /// Handle a C++ member initializer.
4046 Sema::BuildMemInitializer(Decl *ConstructorD,
4047  Scope *S,
4048  CXXScopeSpec &SS,
4049  IdentifierInfo *MemberOrBase,
4050  ParsedType TemplateTypeTy,
4051  const DeclSpec &DS,
4052  SourceLocation IdLoc,
4053  Expr *Init,
4054  SourceLocation EllipsisLoc) {
4055  ExprResult Res = CorrectDelayedTyposInExpr(Init);
4056  if (!Res.isUsable())
4057  return true;
4058  Init = Res.get();
4059 
4060  if (!ConstructorD)
4061  return true;
4062 
4063  AdjustDeclIfTemplate(ConstructorD);
4064 
4065  CXXConstructorDecl *Constructor
4066  = dyn_cast<CXXConstructorDecl>(ConstructorD);
4067  if (!Constructor) {
4068  // The user wrote a constructor initializer on a function that is
4069  // not a C++ constructor. Ignore the error for now, because we may
4070  // have more member initializers coming; we'll diagnose it just
4071  // once in ActOnMemInitializers.
4072  return true;
4073  }
4074 
4075  CXXRecordDecl *ClassDecl = Constructor->getParent();
4076 
4077  // C++ [class.base.init]p2:
4078  // Names in a mem-initializer-id are looked up in the scope of the
4079  // constructor's class and, if not found in that scope, are looked
4080  // up in the scope containing the constructor's definition.
4081  // [Note: if the constructor's class contains a member with the
4082  // same name as a direct or virtual base class of the class, a
4083  // mem-initializer-id naming the member or base class and composed
4084  // of a single identifier refers to the class member. A
4085  // mem-initializer-id for the hidden base class may be specified
4086  // using a qualified name. ]
4087 
4088  // Look for a member, first.
4089  if (ValueDecl *Member = tryLookupCtorInitMemberDecl(
4090  ClassDecl, SS, TemplateTypeTy, MemberOrBase)) {
4091  if (EllipsisLoc.isValid())
4092  Diag(EllipsisLoc, diag::err_pack_expansion_member_init)
4093  << MemberOrBase
4094  << SourceRange(IdLoc, Init->getSourceRange().getEnd());
4095 
4096  return BuildMemberInitializer(Member, Init, IdLoc);
4097  }
4098  // It didn't name a member, so see if it names a class.
4099  QualType BaseType;
4100  TypeSourceInfo *TInfo = nullptr;
4101 
4102  if (TemplateTypeTy) {
4103  BaseType = GetTypeFromParser(TemplateTypeTy, &TInfo);
4104  if (BaseType.isNull())
4105  return true;
4106  } else if (DS.getTypeSpecType() == TST_decltype) {
4107  BaseType = BuildDecltypeType(DS.getRepAsExpr(), DS.getTypeSpecTypeLoc());
4108  } else if (DS.getTypeSpecType() == TST_decltype_auto) {
4109  Diag(DS.getTypeSpecTypeLoc(), diag::err_decltype_auto_invalid);
4110  return true;
4111  } else {
4112  LookupResult R(*this, MemberOrBase, IdLoc, LookupOrdinaryName);
4113  LookupParsedName(R, S, &SS);
4114 
4115  TypeDecl *TyD = R.getAsSingle<TypeDecl>();
4116  if (!TyD) {
4117  if (R.isAmbiguous()) return true;
4118 
4119  // We don't want access-control diagnostics here.
4120  R.suppressDiagnostics();
4121 
4122  if (SS.isSet() && isDependentScopeSpecifier(SS)) {
4123  bool NotUnknownSpecialization = false;
4124  DeclContext *DC = computeDeclContext(SS, false);
4125  if (CXXRecordDecl *Record = dyn_cast_or_null<CXXRecordDecl>(DC))
4126  NotUnknownSpecialization = !Record->hasAnyDependentBases();
4127 
4128  if (!NotUnknownSpecialization) {
4129  // When the scope specifier can refer to a member of an unknown
4130  // specialization, we take it as a type name.
4131  BaseType = CheckTypenameType(ETK_None, SourceLocation(),
4132  SS.getWithLocInContext(Context),
4133  *MemberOrBase, IdLoc);
4134  if (BaseType.isNull())
4135  return true;
4136 
4137  TInfo = Context.CreateTypeSourceInfo(BaseType);
4140  if (!TL.isNull()) {
4141  TL.setNameLoc(IdLoc);
4143  TL.setQualifierLoc(SS.getWithLocInContext(Context));
4144  }
4145 
4146  R.clear();
4147  R.setLookupName(MemberOrBase);
4148  }
4149  }
4150 
4151  // If no results were found, try to correct typos.
4152  TypoCorrection Corr;
4153  MemInitializerValidatorCCC CCC(ClassDecl);
4154  if (R.empty() && BaseType.isNull() &&
4155  (Corr = CorrectTypo(R.getLookupNameInfo(), R.getLookupKind(), S, &SS,
4156  CCC, CTK_ErrorRecovery, ClassDecl))) {
4157  if (FieldDecl *Member = Corr.getCorrectionDeclAs<FieldDecl>()) {
4158  // We have found a non-static data member with a similar
4159  // name to what was typed; complain and initialize that
4160  // member.
4161  diagnoseTypo(Corr,
4162  PDiag(diag::err_mem_init_not_member_or_class_suggest)
4163  << MemberOrBase << true);
4164  return BuildMemberInitializer(Member, Init, IdLoc);
4165  } else if (TypeDecl *Type = Corr.getCorrectionDeclAs<TypeDecl>()) {
4166  const CXXBaseSpecifier *DirectBaseSpec;
4167  const CXXBaseSpecifier *VirtualBaseSpec;
4168  if (FindBaseInitializer(*this, ClassDecl,
4169  Context.getTypeDeclType(Type),
4170  DirectBaseSpec, VirtualBaseSpec)) {
4171  // We have found a direct or virtual base class with a
4172  // similar name to what was typed; complain and initialize
4173  // that base class.
4174  diagnoseTypo(Corr,
4175  PDiag(diag::err_mem_init_not_member_or_class_suggest)
4176  << MemberOrBase << false,
4177  PDiag() /*Suppress note, we provide our own.*/);
4178 
4179  const CXXBaseSpecifier *BaseSpec = DirectBaseSpec ? DirectBaseSpec
4180  : VirtualBaseSpec;
4181  Diag(BaseSpec->getBeginLoc(), diag::note_base_class_specified_here)
4182  << BaseSpec->getType() << BaseSpec->getSourceRange();
4183 
4184  TyD = Type;
4185  }
4186  }
4187  }
4188 
4189  if (!TyD && BaseType.isNull()) {
4190  Diag(IdLoc, diag::err_mem_init_not_member_or_class)
4191  << MemberOrBase << SourceRange(IdLoc,Init->getSourceRange().getEnd());
4192  return true;
4193  }
4194  }
4195 
4196  if (BaseType.isNull()) {
4197  BaseType = Context.getTypeDeclType(TyD);
4198  MarkAnyDeclReferenced(TyD->getLocation(), TyD, /*OdrUse=*/false);
4199  if (SS.isSet()) {
4200  BaseType = Context.getElaboratedType(ETK_None, SS.getScopeRep(),
4201  BaseType);
4202  TInfo = Context.CreateTypeSourceInfo(BaseType);
4204  TL.getNamedTypeLoc().castAs<TypeSpecTypeLoc>().setNameLoc(IdLoc);
4206  TL.setQualifierLoc(SS.getWithLocInContext(Context));
4207  }
4208  }
4209  }
4210 
4211  if (!TInfo)
4212  TInfo = Context.getTrivialTypeSourceInfo(BaseType, IdLoc);
4213 
4214  return BuildBaseInitializer(BaseType, TInfo, Init, ClassDecl, EllipsisLoc);
4215 }
4216 
4219  SourceLocation IdLoc) {
4220  FieldDecl *DirectMember = dyn_cast<FieldDecl>(Member);
4221  IndirectFieldDecl *IndirectMember = dyn_cast<IndirectFieldDecl>(Member);
4222  assert((DirectMember || IndirectMember) &&
4223  "Member must be a FieldDecl or IndirectFieldDecl");
4224 
4225  if (DiagnoseUnexpandedParameterPack(Init, UPPC_Initializer))
4226  return true;
4227 
4228  if (Member->isInvalidDecl())
4229  return true;
4230 
4231  MultiExprArg Args;
4232  if (ParenListExpr *ParenList = dyn_cast<ParenListExpr>(Init)) {
4233  Args = MultiExprArg(ParenList->getExprs(), ParenList->getNumExprs());
4234  } else if (InitListExpr *InitList = dyn_cast<InitListExpr>(Init)) {
4235  Args = MultiExprArg(InitList->getInits(), InitList->getNumInits());
4236  } else {
4237  // Template instantiation doesn't reconstruct ParenListExprs for us.
4238  Args = Init;
4239  }
4240 
4241  SourceRange InitRange = Init->getSourceRange();
4242 
4243  if (Member->getType()->isDependentType() || Init->isTypeDependent()) {
4244  // Can't check initialization for a member of dependent type or when
4245  // any of the arguments are type-dependent expressions.
4246  DiscardCleanupsInEvaluationContext();
4247  } else {
4248  bool InitList = false;
4249  if (isa<InitListExpr>(Init)) {
4250  InitList = true;
4251  Args = Init;
4252  }
4253 
4254  // Initialize the member.
4255  InitializedEntity MemberEntity =
4256  DirectMember ? InitializedEntity::InitializeMember(DirectMember, nullptr)
4257  : InitializedEntity::InitializeMember(IndirectMember,
4258  nullptr);
4259  InitializationKind Kind =
4261  IdLoc, Init->getBeginLoc(), Init->getEndLoc())
4262  : InitializationKind::CreateDirect(IdLoc, InitRange.getBegin(),
4263  InitRange.getEnd());
4264 
4265  InitializationSequence InitSeq(*this, MemberEntity, Kind, Args);
4266  ExprResult MemberInit = InitSeq.Perform(*this, MemberEntity, Kind, Args,
4267  nullptr);
4268  if (MemberInit.isInvalid())
4269  return true;
4270 
4271  // C++11 [class.base.init]p7:
4272  // The initialization of each base and member constitutes a
4273  // full-expression.
4274  MemberInit = ActOnFinishFullExpr(MemberInit.get(), InitRange.getBegin(),
4275  /*DiscardedValue*/ false);
4276  if (MemberInit.isInvalid())
4277  return true;
4278 
4279  Init = MemberInit.get();
4280  }
4281 
4282  if (DirectMember) {
4283  return new (Context) CXXCtorInitializer(Context, DirectMember, IdLoc,
4284  InitRange.getBegin(), Init,
4285  InitRange.getEnd());
4286  } else {
4287  return new (Context) CXXCtorInitializer(Context, IndirectMember, IdLoc,
4288  InitRange.getBegin(), Init,
4289  InitRange.getEnd());
4290  }
4291 }
4292 
4295  CXXRecordDecl *ClassDecl) {
4296  SourceLocation NameLoc = TInfo->getTypeLoc().getLocalSourceRange().getBegin();
4297  if (!LangOpts.CPlusPlus11)
4298  return Diag(NameLoc, diag::err_delegating_ctor)
4299  << TInfo->getTypeLoc().getLocalSourceRange();
4300  Diag(NameLoc, diag::warn_cxx98_compat_delegating_ctor);
4301 
4302  bool InitList = true;
4303  MultiExprArg Args = Init;
4304  if (ParenListExpr *ParenList = dyn_cast<ParenListExpr>(Init)) {
4305  InitList = false;
4306  Args = MultiExprArg(ParenList->getExprs(), ParenList->getNumExprs());
4307  }
4308 
4309  SourceRange InitRange = Init->getSourceRange();
4310  // Initialize the object.
4312  QualType(ClassDecl->getTypeForDecl(), 0));
4313  InitializationKind Kind =
4315  NameLoc, Init->getBeginLoc(), Init->getEndLoc())
4316  : InitializationKind::CreateDirect(NameLoc, InitRange.getBegin(),
4317  InitRange.getEnd());
4318  InitializationSequence InitSeq(*this, DelegationEntity, Kind, Args);
4319  ExprResult DelegationInit = InitSeq.Perform(*this, DelegationEntity, Kind,
4320  Args, nullptr);
4321  if (DelegationInit.isInvalid())
4322  return true;
4323 
4324  assert(cast<CXXConstructExpr>(DelegationInit.get())->getConstructor() &&
4325  "Delegating constructor with no target?");
4326 
4327  // C++11 [class.base.init]p7:
4328  // The initialization of each base and member constitutes a
4329  // full-expression.
4330  DelegationInit = ActOnFinishFullExpr(
4331  DelegationInit.get(), InitRange.getBegin(), /*DiscardedValue*/ false);
4332  if (DelegationInit.isInvalid())
4333  return true;
4334 
4335  // If we are in a dependent context, template instantiation will
4336  // perform this type-checking again. Just save the arguments that we
4337  // received in a ParenListExpr.
4338  // FIXME: This isn't quite ideal, since our ASTs don't capture all
4339  // of the information that we have about the base
4340  // initializer. However, deconstructing the ASTs is a dicey process,
4341  // and this approach is far more likely to get the corner cases right.
4342  if (CurContext->isDependentContext())
4343  DelegationInit = Init;
4344 
4345  return new (Context) CXXCtorInitializer(Context, TInfo, InitRange.getBegin(),
4346  DelegationInit.getAs<Expr>(),
4347  InitRange.getEnd());
4348 }
4349 
4352  Expr *Init, CXXRecordDecl *ClassDecl,
4353  SourceLocation EllipsisLoc) {
4354  SourceLocation BaseLoc
4355  = BaseTInfo->getTypeLoc().getLocalSourceRange().getBegin();
4356 
4357  if (!BaseType->isDependentType() && !BaseType->isRecordType())
4358  return Diag(BaseLoc, diag::err_base_init_does_not_name_class)
4359  << BaseType << BaseTInfo->getTypeLoc().getLocalSourceRange();
4360 
4361  // C++ [class.base.init]p2:
4362  // [...] Unless the mem-initializer-id names a nonstatic data
4363  // member of the constructor's class or a direct or virtual base
4364  // of that class, the mem-initializer is ill-formed. A
4365  // mem-initializer-list can initialize a base class using any
4366  // name that denotes that base class type.
4367  bool Dependent = BaseType->isDependentType() || Init->isTypeDependent();
4368 
4369  SourceRange InitRange = Init->getSourceRange();
4370  if (EllipsisLoc.isValid()) {
4371  // This is a pack expansion.
4372  if (!BaseType->containsUnexpandedParameterPack()) {
4373  Diag(EllipsisLoc, diag::err_pack_expansion_without_parameter_packs)
4374  << SourceRange(BaseLoc, InitRange.getEnd());
4375 
4376  EllipsisLoc = SourceLocation();
4377  }
4378  } else {
4379  // Check for any unexpanded parameter packs.
4380  if (DiagnoseUnexpandedParameterPack(BaseLoc, BaseTInfo, UPPC_Initializer))
4381  return true;
4382 
4383  if (DiagnoseUnexpandedParameterPack(Init, UPPC_Initializer))
4384  return true;
4385  }
4386 
4387  // Check for direct and virtual base classes.
4388  const CXXBaseSpecifier *DirectBaseSpec = nullptr;
4389  const CXXBaseSpecifier *VirtualBaseSpec = nullptr;
4390  if (!Dependent) {
4391  if (Context.hasSameUnqualifiedType(QualType(ClassDecl->getTypeForDecl(),0),
4392  BaseType))
4393  return BuildDelegatingInitializer(BaseTInfo, Init, ClassDecl);
4394 
4395  FindBaseInitializer(*this, ClassDecl, BaseType, DirectBaseSpec,
4396  VirtualBaseSpec);
4397 
4398  // C++ [base.class.init]p2:
4399  // Unless the mem-initializer-id names a nonstatic data member of the
4400  // constructor's class or a direct or virtual base of that class, the
4401  // mem-initializer is ill-formed.
4402  if (!DirectBaseSpec && !VirtualBaseSpec) {
4403  // If the class has any dependent bases, then it's possible that
4404  // one of those types will resolve to the same type as
4405  // BaseType. Therefore, just treat this as a dependent base
4406  // class initialization. FIXME: Should we try to check the
4407  // initialization anyway? It seems odd.
4408  if (ClassDecl->hasAnyDependentBases())
4409  Dependent = true;
4410  else
4411  return Diag(BaseLoc, diag::err_not_direct_base_or_virtual)
4412  << BaseType << Context.getTypeDeclType(ClassDecl)
4413  << BaseTInfo->getTypeLoc().getLocalSourceRange();
4414  }
4415  }
4416 
4417  if (Dependent) {
4418  DiscardCleanupsInEvaluationContext();
4419 
4420  return new (Context) CXXCtorInitializer(Context, BaseTInfo,
4421  /*IsVirtual=*/false,
4422  InitRange.getBegin(), Init,
4423  InitRange.getEnd(), EllipsisLoc);
4424  }
4425 
4426  // C++ [base.class.init]p2:
4427  // If a mem-initializer-id is ambiguous because it designates both
4428  // a direct non-virtual base class and an inherited virtual base
4429  // class, the mem-initializer is ill-formed.
4430  if (DirectBaseSpec && VirtualBaseSpec)
4431  return Diag(BaseLoc, diag::err_base_init_direct_and_virtual)
4432  << BaseType << BaseTInfo->getTypeLoc().getLocalSourceRange();
4433 
4434  const CXXBaseSpecifier *BaseSpec = DirectBaseSpec;
4435  if (!BaseSpec)
4436  BaseSpec = VirtualBaseSpec;
4437 
4438  // Initialize the base.
4439  bool InitList = true;
4440  MultiExprArg Args = Init;
4441  if (ParenListExpr *ParenList = dyn_cast<ParenListExpr>(Init)) {
4442  InitList = false;
4443  Args = MultiExprArg(ParenList->getExprs(), ParenList->getNumExprs());
4444  }
4445 
4446  InitializedEntity BaseEntity =
4447  InitializedEntity::InitializeBase(Context, BaseSpec, VirtualBaseSpec);
4448  InitializationKind Kind =
4449  InitList ? InitializationKind::CreateDirectList(BaseLoc)
4450  : InitializationKind::CreateDirect(BaseLoc, InitRange.getBegin(),
4451  InitRange.getEnd());
4452  InitializationSequence InitSeq(*this, BaseEntity, Kind, Args);
4453  ExprResult BaseInit = InitSeq.Perform(*this, BaseEntity, Kind, Args, nullptr);
4454  if (BaseInit.isInvalid())
4455  return true;
4456 
4457  // C++11 [class.base.init]p7:
4458  // The initialization of each base and member constitutes a
4459  // full-expression.
4460  BaseInit = ActOnFinishFullExpr(BaseInit.get(), InitRange.getBegin(),
4461  /*DiscardedValue*/ false);
4462  if (BaseInit.isInvalid())
4463  return true;
4464 
4465  // If we are in a dependent context, template instantiation will
4466  // perform this type-checking again. Just save the arguments that we
4467  // received in a ParenListExpr.
4468  // FIXME: This isn't quite ideal, since our ASTs don't capture all
4469  // of the information that we have about the base
4470  // initializer. However, deconstructing the ASTs is a dicey process,
4471  // and this approach is far more likely to get the corner cases right.
4472  if (CurContext->isDependentContext())
4473  BaseInit = Init;
4474 
4475  return new (Context) CXXCtorInitializer(Context, BaseTInfo,
4476  BaseSpec->isVirtual(),
4477  InitRange.getBegin(),
4478  BaseInit.getAs<Expr>(),
4479  InitRange.getEnd(), EllipsisLoc);
4480 }
4481 
4482 // Create a static_cast<T&&>(expr).
4483 static Expr *CastForMoving(Sema &SemaRef, Expr *E, QualType T = QualType()) {
4484  if (T.isNull()) T = E->getType();
4485  QualType TargetType = SemaRef.BuildReferenceType(
4486  T, /*SpelledAsLValue*/false, SourceLocation(), DeclarationName());
4487  SourceLocation ExprLoc = E->getBeginLoc();
4488  TypeSourceInfo *TargetLoc = SemaRef.Context.getTrivialTypeSourceInfo(
4489  TargetType, ExprLoc);
4490 
4491  return SemaRef.BuildCXXNamedCast(ExprLoc, tok::kw_static_cast, TargetLoc, E,
4492  SourceRange(ExprLoc, ExprLoc),
4493  E->getSourceRange()).get();
4494 }
4495 
4496 /// ImplicitInitializerKind - How an implicit base or member initializer should
4497 /// initialize its base or member.
4503 };
4504 
4505 static bool
4507  ImplicitInitializerKind ImplicitInitKind,
4508  CXXBaseSpecifier *BaseSpec,
4509  bool IsInheritedVirtualBase,
4510  CXXCtorInitializer *&CXXBaseInit) {
4511  InitializedEntity InitEntity
4512  = InitializedEntity::InitializeBase(SemaRef.Context, BaseSpec,
4513  IsInheritedVirtualBase);
4514 
4515  ExprResult BaseInit;
4516 
4517  switch (ImplicitInitKind) {
4518  case IIK_Inherit:
4519  case IIK_Default: {
4520  InitializationKind InitKind
4522  InitializationSequence InitSeq(SemaRef, InitEntity, InitKind, None);
4523  BaseInit = InitSeq.Perform(SemaRef, InitEntity, InitKind, None);
4524  break;
4525  }
4526 
4527  case IIK_Move:
4528  case IIK_Copy: {
4529  bool Moving = ImplicitInitKind == IIK_Move;
4530  ParmVarDecl *Param = Constructor->getParamDecl(0);
4531  QualType ParamType = Param->getType().getNonReferenceType();
4532 
4533  Expr *CopyCtorArg =
4535  SourceLocation(), Param, false,
4536  Constructor->getLocation(), ParamType,
4537  VK_LValue, nullptr);
4538 
4539  SemaRef.MarkDeclRefReferenced(cast<DeclRefExpr>(CopyCtorArg));
4540 
4541  // Cast to the base class to avoid ambiguities.
4542  QualType ArgTy =
4543  SemaRef.Context.getQualifiedType(BaseSpec->getType().getUnqualifiedType(),
4544  ParamType.getQualifiers());
4545 
4546  if (Moving) {
4547  CopyCtorArg = CastForMoving(SemaRef, CopyCtorArg);
4548  }
4549 
4550  CXXCastPath BasePath;
4551  BasePath.push_back(BaseSpec);
4552  CopyCtorArg = SemaRef.ImpCastExprToType(CopyCtorArg, ArgTy,
4553  CK_UncheckedDerivedToBase,
4554  Moving ? VK_XValue : VK_LValue,
4555  &BasePath).get();
4556 
4557  InitializationKind InitKind
4560  InitializationSequence InitSeq(SemaRef, InitEntity, InitKind, CopyCtorArg);
4561  BaseInit = InitSeq.Perform(SemaRef, InitEntity, InitKind, CopyCtorArg);
4562  break;
4563  }
4564  }
4565 
4566  BaseInit = SemaRef.MaybeCreateExprWithCleanups(BaseInit);
4567  if (BaseInit.isInvalid())
4568  return true;
4569 
4570  CXXBaseInit =
4571  new (SemaRef.Context) CXXCtorInitializer(SemaRef.Context,
4572  SemaRef.Context.getTrivialTypeSourceInfo(BaseSpec->getType(),
4573  SourceLocation()),
4574  BaseSpec->isVirtual(),
4575  SourceLocation(),
4576  BaseInit.getAs<Expr>(),
4577  SourceLocation(),
4578  SourceLocation());
4579 
4580  return false;
4581 }
4582 
4583 static bool RefersToRValueRef(Expr *MemRef) {
4584  ValueDecl *Referenced = cast<MemberExpr>(MemRef)->getMemberDecl();
4585  return Referenced->getType()->isRValueReferenceType();
4586 }
4587 
4588 static bool
4590  ImplicitInitializerKind ImplicitInitKind,
4591  FieldDecl *Field, IndirectFieldDecl *Indirect,
4592  CXXCtorInitializer *&CXXMemberInit) {
4593  if (Field->isInvalidDecl())
4594  return true;
4595 
4596  SourceLocation Loc = Constructor->getLocation();
4597 
4598  if (ImplicitInitKind == IIK_Copy || ImplicitInitKind == IIK_Move) {
4599  bool Moving = ImplicitInitKind == IIK_Move;
4600  ParmVarDecl *Param = Constructor->getParamDecl(0);
4601  QualType ParamType = Param->getType().getNonReferenceType();
4602 
4603  // Suppress copying zero-width bitfields.
4604  if (Field->isZeroLengthBitField(SemaRef.Context))
4605  return false;
4606 
4607  Expr *MemberExprBase =
4609  SourceLocation(), Param, false,
4610  Loc, ParamType, VK_LValue, nullptr);
4611 
4612  SemaRef.MarkDeclRefReferenced(cast<DeclRefExpr>(MemberExprBase));
4613 
4614  if (Moving) {
4615  MemberExprBase = CastForMoving(SemaRef, MemberExprBase);
4616  }
4617 
4618  // Build a reference to this field within the parameter.
4619  CXXScopeSpec SS;
4620  LookupResult MemberLookup(SemaRef, Field->getDeclName(), Loc,
4622  MemberLookup.addDecl(Indirect ? cast<ValueDecl>(Indirect)
4623  : cast<ValueDecl>(Field), AS_public);
4624  MemberLookup.resolveKind();
4625  ExprResult CtorArg
4626  = SemaRef.BuildMemberReferenceExpr(MemberExprBase,
4627  ParamType, Loc,
4628  /*IsArrow=*/false,
4629  SS,
4630  /*TemplateKWLoc=*/SourceLocation(),
4631  /*FirstQualifierInScope=*/nullptr,
4632  MemberLookup,
4633  /*TemplateArgs=*/nullptr,
4634  /*S*/nullptr);
4635  if (CtorArg.isInvalid())
4636  return true;
4637 
4638  // C++11 [class.copy]p15:
4639  // - if a member m has rvalue reference type T&&, it is direct-initialized
4640  // with static_cast<T&&>(x.m);
4641  if (RefersToRValueRef(CtorArg.get())) {
4642  CtorArg = CastForMoving(SemaRef, CtorArg.get());
4643  }
4644 
4645  InitializedEntity Entity =
4646  Indirect ? InitializedEntity::InitializeMember(Indirect, nullptr,
4647  /*Implicit*/ true)
4648  : InitializedEntity::InitializeMember(Field, nullptr,
4649  /*Implicit*/ true);
4650 
4651  // Direct-initialize to use the copy constructor.
4652  InitializationKind InitKind =
4654 
4655  Expr *CtorArgE = CtorArg.getAs<Expr>();
4656  InitializationSequence InitSeq(SemaRef, Entity, InitKind, CtorArgE);
4657  ExprResult MemberInit =
4658  InitSeq.Perform(SemaRef, Entity, InitKind, MultiExprArg(&CtorArgE, 1));
4659  MemberInit = SemaRef.MaybeCreateExprWithCleanups(MemberInit);
4660  if (MemberInit.isInvalid())
4661  return true;
4662 
4663  if (Indirect)
4664  CXXMemberInit = new (SemaRef.Context) CXXCtorInitializer(
4665  SemaRef.Context, Indirect, Loc, Loc, MemberInit.getAs<Expr>(), Loc);
4666  else
4667  CXXMemberInit = new (SemaRef.Context) CXXCtorInitializer(
4668  SemaRef.Context, Field, Loc, Loc, MemberInit.getAs<Expr>(), Loc);
4669  return false;
4670  }
4671 
4672  assert((ImplicitInitKind == IIK_Default || ImplicitInitKind == IIK_Inherit) &&
4673  "Unhandled implicit init kind!");
4674 
4675  QualType FieldBaseElementType =
4676  SemaRef.Context.getBaseElementType(Field->getType());
4677 
4678  if (FieldBaseElementType->isRecordType()) {
4679  InitializedEntity InitEntity =
4680  Indirect ? InitializedEntity::InitializeMember(Indirect, nullptr,
4681  /*Implicit*/ true)
4682  : InitializedEntity::InitializeMember(Field, nullptr,
4683  /*Implicit*/ true);
4684  InitializationKind InitKind =
4686 
4687  InitializationSequence InitSeq(SemaRef, InitEntity, InitKind, None);
4688  ExprResult MemberInit =
4689  InitSeq.Perform(SemaRef, InitEntity, InitKind, None);
4690 
4691  MemberInit = SemaRef.MaybeCreateExprWithCleanups(MemberInit);
4692  if (MemberInit.isInvalid())
4693  return true;
4694 
4695  if (Indirect)
4696  CXXMemberInit = new (SemaRef.Context) CXXCtorInitializer(SemaRef.Context,
4697  Indirect, Loc,
4698  Loc,
4699  MemberInit.get(),
4700  Loc);
4701  else
4702  CXXMemberInit = new (SemaRef.Context) CXXCtorInitializer(SemaRef.Context,
4703  Field, Loc, Loc,
4704  MemberInit.get(),
4705  Loc);
4706  return false;
4707  }
4708 
4709  if (!Field->getParent()->isUnion()) {
4710  if (FieldBaseElementType->isReferenceType()) {
4711  SemaRef.Diag(Constructor->getLocation(),
4712  diag::err_uninitialized_member_in_ctor)
4713  << (int)Constructor->isImplicit()
4714  << SemaRef.Context.getTagDeclType(Constructor->getParent())
4715  << 0 << Field->getDeclName();
4716  SemaRef.Diag(Field->getLocation(), diag::note_declared_at);
4717  return true;
4718  }
4719 
4720  if (FieldBaseElementType.isConstQualified()) {
4721  SemaRef.Diag(Constructor->getLocation(),
4722  diag::err_uninitialized_member_in_ctor)
4723  << (int)Constructor->isImplicit()
4724  << SemaRef.Context.getTagDeclType(Constructor->getParent())
4725  << 1 << Field->getDeclName();
4726  SemaRef.Diag(Field->getLocation(), diag::note_declared_at);
4727  return true;
4728  }
4729  }
4730 
4731  if (FieldBaseElementType.hasNonTrivialObjCLifetime()) {
4732  // ARC and Weak:
4733  // Default-initialize Objective-C pointers to NULL.
4734  CXXMemberInit
4735  = new (SemaRef.Context) CXXCtorInitializer(SemaRef.Context, Field,
4736  Loc, Loc,
4737  new (SemaRef.Context) ImplicitValueInitExpr(Field->getType()),
4738  Loc);
4739  return false;
4740  }
4741 
4742  // Nothing to initialize.
4743  CXXMemberInit = nullptr;
4744  return false;
4745 }
4746 
4747 namespace {
4748 struct BaseAndFieldInfo {
4749  Sema &S;
4750  CXXConstructorDecl *Ctor;
4751  bool AnyErrorsInInits;
4753  llvm::DenseMap<const void *, CXXCtorInitializer*> AllBaseFields;
4755  llvm::DenseMap<TagDecl*, FieldDecl*> ActiveUnionMember;
4756 
4757  BaseAndFieldInfo(Sema &S, CXXConstructorDecl *Ctor, bool ErrorsInInits)
4758  : S(S), Ctor(Ctor), AnyErrorsInInits(ErrorsInInits) {
4759  bool Generated = Ctor->isImplicit() || Ctor->isDefaulted();
4760  if (Ctor->getInheritedConstructor())
4761  IIK = IIK_Inherit;
4762  else if (Generated && Ctor->isCopyConstructor())
4763  IIK = IIK_Copy;
4764  else if (Generated && Ctor->isMoveConstructor())
4765  IIK = IIK_Move;
4766  else
4767  IIK = IIK_Default;
4768  }
4769 
4770  bool isImplicitCopyOrMove() const {
4771  switch (IIK) {
4772  case IIK_Copy:
4773  case IIK_Move:
4774  return true;
4775 
4776  case IIK_Default:
4777  case IIK_Inherit:
4778  return false;
4779  }
4780 
4781  llvm_unreachable("Invalid ImplicitInitializerKind!");
4782  }
4783 
4784  bool addFieldInitializer(CXXCtorInitializer *Init) {
4785  AllToInit.push_back(Init);
4786 
4787  // Check whether this initializer makes the field "used".
4788  if (Init->getInit()->HasSideEffects(S.Context))
4789  S.UnusedPrivateFields.remove(Init->getAnyMember());
4790 
4791  return false;
4792  }
4793 
4794  bool isInactiveUnionMember(FieldDecl *Field) {
4795  RecordDecl *Record = Field->getParent();
4796  if (!Record->isUnion())
4797  return false;
4798 
4799  if (FieldDecl *Active =
4800  ActiveUnionMember.lookup(Record->getCanonicalDecl()))
4801  return Active != Field->getCanonicalDecl();
4802 
4803  // In an implicit copy or move constructor, ignore any in-class initializer.
4804  if (isImplicitCopyOrMove())
4805  return true;
4806 
4807  // If there's no explicit initialization, the field is active only if it
4808  // has an in-class initializer...
4809  if (Field->hasInClassInitializer())
4810  return false;
4811  // ... or it's an anonymous struct or union whose class has an in-class
4812  // initializer.
4813  if (!Field->isAnonymousStructOrUnion())
4814  return true;
4815  CXXRecordDecl *FieldRD = Field->getType()->getAsCXXRecordDecl();
4816  return !FieldRD->hasInClassInitializer();
4817  }
4818 
4819  /// Determine whether the given field is, or is within, a union member
4820  /// that is inactive (because there was an initializer given for a different
4821  /// member of the union, or because the union was not initialized at all).
4822  bool isWithinInactiveUnionMember(FieldDecl *Field,
4823  IndirectFieldDecl *Indirect) {
4824  if (!Indirect)
4825  return isInactiveUnionMember(Field);
4826 
4827  for (auto *C : Indirect->chain()) {
4828  FieldDecl *Field = dyn_cast<FieldDecl>(C);
4829  if (Field && isInactiveUnionMember(Field))
4830  return true;
4831  }
4832  return false;
4833  }
4834 };
4835 }
4836 
4837 /// Determine whether the given type is an incomplete or zero-lenfgth
4838 /// array type.
4840  if (T->isIncompleteArrayType())
4841  return true;
4842 
4843  while (const ConstantArrayType *ArrayT = Context.getAsConstantArrayType(T)) {
4844  if (!ArrayT->getSize())
4845  return true;
4846 
4847  T = ArrayT->getElementType();
4848  }
4849 
4850  return false;
4851 }
4852 
4853 static bool CollectFieldInitializer(Sema &SemaRef, BaseAndFieldInfo &Info,
4854  FieldDecl *Field,
4855  IndirectFieldDecl *Indirect = nullptr) {
4856  if (Field->isInvalidDecl())
4857  return false;
4858 
4859  // Overwhelmingly common case: we have a direct initializer for this field.
4860  if (CXXCtorInitializer *Init =
4861  Info.AllBaseFields.lookup(Field->getCanonicalDecl()))
4862  return Info.addFieldInitializer(Init);
4863 
4864  // C++11 [class.base.init]p8:
4865  // if the entity is a non-static data member that has a
4866  // brace-or-equal-initializer and either
4867  // -- the constructor's class is a union and no other variant member of that
4868  // union is designated by a mem-initializer-id or
4869  // -- the constructor's class is not a union, and, if the entity is a member
4870  // of an anonymous union, no other member of that union is designated by
4871  // a mem-initializer-id,
4872  // the entity is initialized as specified in [dcl.init].
4873  //
4874  // We also apply the same rules to handle anonymous structs within anonymous
4875  // unions.
4876  if (Info.isWithinInactiveUnionMember(Field, Indirect))
4877  return false;
4878 
4879  if (Field->hasInClassInitializer() && !Info.isImplicitCopyOrMove()) {
4880  ExprResult DIE =
4881  SemaRef.BuildCXXDefaultInitExpr(Info.Ctor->getLocation(), Field);
4882  if (DIE.isInvalid())
4883  return true;
4884 
4885  auto Entity = InitializedEntity::InitializeMember(Field, nullptr, true);
4886  SemaRef.checkInitializerLifetime(Entity, DIE.get());
4887 
4888  CXXCtorInitializer *Init;
4889  if (Indirect)
4890  Init = new (SemaRef.Context)
4891  CXXCtorInitializer(SemaRef.Context, Indirect, SourceLocation(),
4892  SourceLocation(), DIE.get(), SourceLocation());
4893  else
4894  Init = new (SemaRef.Context)
4895  CXXCtorInitializer(SemaRef.Context, Field, SourceLocation(),
4896  SourceLocation(), DIE.get(), SourceLocation());
4897  return Info.addFieldInitializer(Init);
4898  }
4899 
4900  // Don't initialize incomplete or zero-length arrays.
4901  if (isIncompleteOrZeroLengthArrayType(SemaRef.Context, Field->getType()))
4902  return false;
4903 
4904  // Don't try to build an implicit initializer if there were semantic
4905  // errors in any of the initializers (and therefore we might be
4906  // missing some that the user actually wrote).
4907  if (Info.AnyErrorsInInits)
4908  return false;
4909 
4910  CXXCtorInitializer *Init = nullptr;
4911  if (BuildImplicitMemberInitializer(Info.S, Info.Ctor, Info.IIK, Field,
4912  Indirect, Init))
4913  return true;
4914 
4915  if (!Init)
4916  return false;
4917 
4918  return Info.addFieldInitializer(Init);
4919 }
4920 
4921 bool
4924  assert(Initializer->isDelegatingInitializer());
4925  Constructor->setNumCtorInitializers(1);
4926  CXXCtorInitializer **initializer =
4927  new (Context) CXXCtorInitializer*[1];
4928  memcpy(initializer, &Initializer, sizeof (CXXCtorInitializer*));
4929  Constructor->setCtorInitializers(initializer);
4930 
4931  if (CXXDestructorDecl *Dtor = LookupDestructor(Constructor->getParent())) {
4932  MarkFunctionReferenced(Initializer->getSourceLocation(), Dtor);
4933  DiagnoseUseOfDecl(Dtor, Initializer->getSourceLocation());
4934  }
4935 
4936  DelegatingCtorDecls.push_back(Constructor);
4937 
4938  DiagnoseUninitializedFields(*this, Constructor);
4939 
4940  return false;
4941 }
4942 
4943 bool Sema::SetCtorInitializers(CXXConstructorDecl *Constructor, bool AnyErrors,
4944  ArrayRef<CXXCtorInitializer *> Initializers) {
4945  if (Constructor->isDependentContext()) {
4946  // Just store the initializers as written, they will be checked during
4947  // instantiation.
4948  if (!Initializers.empty()) {
4949  Constructor->setNumCtorInitializers(Initializers.size());
4950  CXXCtorInitializer **baseOrMemberInitializers =
4951  new (Context) CXXCtorInitializer*[Initializers.size()];
4952  memcpy(baseOrMemberInitializers, Initializers.data(),
4953  Initializers.size() * sizeof(CXXCtorInitializer*));
4954  Constructor->setCtorInitializers(baseOrMemberInitializers);
4955  }
4956 
4957  // Let template instantiation know whether we had errors.
4958  if (AnyErrors)
4959  Constructor->setInvalidDecl();
4960 
4961  return false;
4962  }
4963 
4964  BaseAndFieldInfo Info(*this, Constructor, AnyErrors);
4965 
4966  // We need to build the initializer AST according to order of construction
4967  // and not what user specified in the Initializers list.
4968  CXXRecordDecl *ClassDecl = Constructor->getParent()->getDefinition();
4969  if (!ClassDecl)
4970  return true;
4971 
4972  bool HadError = false;
4973 
4974  for (unsigned i = 0; i < Initializers.size(); i++) {
4975  CXXCtorInitializer *Member = Initializers[i];
4976 
4977  if (Member->isBaseInitializer())
4978  Info.AllBaseFields[Member->getBaseClass()->getAs<RecordType>()] = Member;
4979  else {
4980  Info.AllBaseFields[Member->getAnyMember()->getCanonicalDecl()] = Member;
4981 
4982  if (IndirectFieldDecl *F = Member->getIndirectMember()) {
4983  for (auto *C : F->chain()) {
4984  FieldDecl *FD = dyn_cast<FieldDecl>(C);
4985  if (FD && FD->getParent()->isUnion())
4986  Info.ActiveUnionMember.insert(std::make_pair(
4987  FD->getParent()->getCanonicalDecl(), FD->getCanonicalDecl()));
4988  }
4989  } else if (FieldDecl *FD = Member->getMember()) {
4990  if (FD->getParent()->isUnion())
4991  Info.ActiveUnionMember.insert(std::make_pair(
4992  FD->getParent()->getCanonicalDecl(), FD->getCanonicalDecl()));
4993  }
4994  }
4995  }
4996 
4997  // Keep track of the direct virtual bases.
4998  llvm::SmallPtrSet<CXXBaseSpecifier *, 16> DirectVBases;
4999  for (auto &I : ClassDecl->bases()) {
5000  if (I.isVirtual())
5001  DirectVBases.insert(&I);
5002  }
5003 
5004  // Push virtual bases before others.
5005  for (auto &VBase : ClassDecl->vbases()) {
5007  = Info.AllBaseFields.lookup(VBase.getType()->getAs<RecordType>())) {
5008  // [class.base.init]p7, per DR257:
5009  // A mem-initializer where the mem-initializer-id names a virtual base
5010  // class is ignored during execution of a constructor of any class that
5011  // is not the most derived class.
5012  if (ClassDecl->isAbstract()) {
5013  // FIXME: Provide a fixit to remove the base specifier. This requires
5014  // tracking the location of the associated comma for a base specifier.
5015  Diag(Value->getSourceLocation(), diag::warn_abstract_vbase_init_ignored)
5016  << VBase.getType() << ClassDecl;
5017  DiagnoseAbstractType(ClassDecl);
5018  }
5019 
5020  Info.AllToInit.push_back(Value);
5021  } else if (!AnyErrors && !ClassDecl->isAbstract()) {
5022  // [class.base.init]p8, per DR257:
5023  // If a given [...] base class is not named by a mem-initializer-id
5024  // [...] and the entity is not a virtual base class of an abstract
5025  // class, then [...] the entity is default-initialized.
5026  bool IsInheritedVirtualBase = !DirectVBases.count(&VBase);
5027  CXXCtorInitializer *CXXBaseInit;
5028  if (BuildImplicitBaseInitializer(*this, Constructor, Info.IIK,
5029  &VBase, IsInheritedVirtualBase,
5030  CXXBaseInit)) {
5031  HadError = true;
5032  continue;
5033  }
5034 
5035  Info.AllToInit.push_back(CXXBaseInit);
5036  }
5037  }
5038 
5039  // Non-virtual bases.
5040  for (auto &Base : ClassDecl->bases()) {
5041  // Virtuals are in the virtual base list and already constructed.
5042  if (Base.isVirtual())
5043  continue;
5044 
5046  = Info.AllBaseFields.lookup(Base.getType()->getAs<RecordType>())) {
5047  Info.AllToInit.push_back(Value);
5048  } else if (!AnyErrors) {
5049  CXXCtorInitializer *CXXBaseInit;
5050  if (BuildImplicitBaseInitializer(*this, Constructor, Info.IIK,
5051  &Base, /*IsInheritedVirtualBase=*/false,
5052  CXXBaseInit)) {
5053  HadError = true;
5054  continue;
5055  }
5056 
5057  Info.AllToInit.push_back(CXXBaseInit);
5058  }
5059  }
5060 
5061  // Fields.
5062  for (auto *Mem : ClassDecl->decls()) {
5063  if (auto *F = dyn_cast<FieldDecl>(Mem)) {
5064  // C++ [class.bit]p2:
5065  // A declaration for a bit-field that omits the identifier declares an
5066  // unnamed bit-field. Unnamed bit-fields are not members and cannot be
5067  // initialized.
5068  if (F->isUnnamedBitfield())
5069  continue;
5070 
5071  // If we're not generating the implicit copy/move constructor, then we'll
5072  // handle anonymous struct/union fields based on their individual
5073  // indirect fields.
5074  if (F->isAnonymousStructOrUnion() && !Info.isImplicitCopyOrMove())
5075  continue;
5076 
5077  if (CollectFieldInitializer(*this, Info, F))
5078  HadError = true;
5079  continue;
5080  }
5081 
5082  // Beyond this point, we only consider default initialization.
5083  if (Info.isImplicitCopyOrMove())
5084  continue;
5085 
5086  if (auto *F = dyn_cast<IndirectFieldDecl>(Mem)) {
5087  if (F->getType()->isIncompleteArrayType()) {
5088  assert(ClassDecl->hasFlexibleArrayMember() &&
5089  "Incomplete array type is not valid");
5090  continue;
5091  }
5092 
5093  // Initialize each field of an anonymous struct individually.
5094  if (CollectFieldInitializer(*this, Info, F->getAnonField(), F))
5095  HadError = true;
5096 
5097  continue;
5098  }
5099  }
5100 
5101  unsigned NumInitializers = Info.AllToInit.size();
5102  if (NumInitializers > 0) {
5103  Constructor->setNumCtorInitializers(NumInitializers);
5104  CXXCtorInitializer **baseOrMemberInitializers =
5105  new (Context) CXXCtorInitializer*[NumInitializers];
5106  memcpy(baseOrMemberInitializers, Info.AllToInit.data(),
5107  NumInitializers * sizeof(CXXCtorInitializer*));
5108  Constructor->setCtorInitializers(baseOrMemberInitializers);
5109 
5110  // Constructors implicitly reference the base and member
5111  // destructors.
5112  MarkBaseAndMemberDestructorsReferenced(Constructor->getLocation(),
5113  Constructor->getParent());
5114  }
5115 
5116  return HadError;
5117 }
5118 
5120  if (const RecordType *RT = Field->getType()->getAs<RecordType>()) {
5121  const RecordDecl *RD = RT->getDecl();
5122  if (RD->isAnonymousStructOrUnion()) {
5123  for (auto *Field : RD->fields())
5124  PopulateKeysForFields(Field, IdealInits);
5125  return;
5126  }
5127  }
5128  IdealInits.push_back(Field->getCanonicalDecl());
5129 }
5130 
5131 static const void *GetKeyForBase(ASTContext &Context, QualType BaseType) {
5132  return Context.getCanonicalType(BaseType).getTypePtr();
5133 }
5134 
5135 static const void *GetKeyForMember(ASTContext &Context,
5136  CXXCtorInitializer *Member) {
5137  if (!Member->isAnyMemberInitializer())
5138  return GetKeyForBase(Context, QualType(Member->getBaseClass(), 0));
5139 
5140  return Member->getAnyMember()->getCanonicalDecl();
5141 }
5142 
5144  Sema &SemaRef, const CXXConstructorDecl *Constructor,
5146  if (Constructor->getDeclContext()->isDependentContext())
5147  return;
5148 
5149  // Don't check initializers order unless the warning is enabled at the
5150  // location of at least one initializer.
5151  bool ShouldCheckOrder = false;
5152  for (unsigned InitIndex = 0; InitIndex != Inits.size(); ++InitIndex) {
5153  CXXCtorInitializer *Init = Inits[InitIndex];
5154  if (!SemaRef.Diags.isIgnored(diag::warn_initializer_out_of_order,
5155  Init->getSourceLocation())) {
5156  ShouldCheckOrder = true;
5157  break;
5158  }
5159  }
5160  if (!ShouldCheckOrder)
5161  return;
5162 
5163  // Build the list of bases and members in the order that they'll
5164  // actually be initialized. The explicit initializers should be in
5165  // this same order but may be missing things.
5166  SmallVector<const void*, 32> IdealInitKeys;
5167 
5168  const CXXRecordDecl *ClassDecl = Constructor->getParent();
5169 
5170  // 1. Virtual bases.
5171  for (const auto &VBase : ClassDecl->vbases())
5172  IdealInitKeys.push_back(GetKeyForBase(SemaRef.Context, VBase.getType()));
5173 
5174  // 2. Non-virtual bases.
5175  for (const auto &Base : ClassDecl->bases()) {
5176  if (Base.isVirtual())
5177  continue;
5178  IdealInitKeys.push_back(GetKeyForBase(SemaRef.Context, Base.getType()));
5179  }
5180 
5181  // 3. Direct fields.
5182  for (auto *Field : ClassDecl->fields()) {
5183  if (Field->isUnnamedBitfield())
5184  continue;
5185 
5186  PopulateKeysForFields(Field, IdealInitKeys);
5187  }
5188 
5189  unsigned NumIdealInits = IdealInitKeys.size();
5190  unsigned IdealIndex = 0;
5191 
5192  CXXCtorInitializer *PrevInit = nullptr;
5193  for (unsigned InitIndex = 0; InitIndex != Inits.size(); ++InitIndex) {
5194  CXXCtorInitializer *Init = Inits[InitIndex];
5195  const void *InitKey = GetKeyForMember(SemaRef.Context, Init);
5196 
5197  // Scan forward to try to find this initializer in the idealized
5198  // initializers list.
5199  for (; IdealIndex != NumIdealInits; ++IdealIndex)
5200  if (InitKey == IdealInitKeys[IdealIndex])
5201  break;
5202 
5203  // If we didn't find this initializer, it must be because we
5204  // scanned past it on a previous iteration. That can only
5205  // happen if we're out of order; emit a warning.
5206  if (IdealIndex == NumIdealInits && PrevInit) {
5208  SemaRef.Diag(PrevInit->getSourceLocation(),
5209  diag::warn_initializer_out_of_order);
5210 
5211  if (PrevInit->isAnyMemberInitializer())
5212  D << 0 << PrevInit->getAnyMember()->getDeclName();
5213  else
5214  D << 1 << PrevInit->getTypeSourceInfo()->getType();
5215 
5216  if (Init->isAnyMemberInitializer())
5217  D << 0 << Init->getAnyMember()->getDeclName();
5218  else
5219  D << 1 << Init->getTypeSourceInfo()->getType();
5220 
5221  // Move back to the initializer's location in the ideal list.
5222  for (IdealIndex = 0; IdealIndex != NumIdealInits; ++IdealIndex)
5223  if (InitKey == IdealInitKeys[IdealIndex])
5224  break;
5225 
5226  assert(IdealIndex < NumIdealInits &&
5227  "initializer not found in initializer list");
5228  }
5229 
5230  PrevInit = Init;
5231  }
5232 }
5233 
5234 namespace {
5235 bool CheckRedundantInit(Sema &S,
5236  CXXCtorInitializer *Init,
5237  CXXCtorInitializer *&PrevInit) {
5238  if (!PrevInit) {
5239  PrevInit = Init;
5240  return false;
5241  }
5242 
5243  if (FieldDecl *Field = Init->getAnyMember())
5244  S.Diag(Init->getSourceLocation(),
5245  diag::err_multiple_mem_initialization)
5246  << Field->getDeclName()
5247  << Init->getSourceRange();
5248  else {
5249  const Type *BaseClass = Init->getBaseClass();
5250  assert(BaseClass && "neither field nor base");
5251  S.Diag(Init->getSourceLocation(),
5252  diag::err_multiple_base_initialization)
5253  << QualType(BaseClass, 0)
5254  << Init->getSourceRange();
5255  }
5256  S.Diag(PrevInit->getSourceLocation(), diag::note_previous_initializer)
5257  << 0 << PrevInit->getSourceRange();
5258 
5259  return true;
5260 }
5261 
5262 typedef std::pair<NamedDecl *, CXXCtorInitializer *> UnionEntry;
5263 typedef llvm::DenseMap<RecordDecl*, UnionEntry> RedundantUnionMap;
5264 
5265 bool CheckRedundantUnionInit(Sema &S,
5266  CXXCtorInitializer *Init,
5267  RedundantUnionMap &Unions) {
5268  FieldDecl *Field = Init->getAnyMember();
5269  RecordDecl *Parent = Field->getParent();
5270  NamedDecl *Child = Field;
5271 
5272  while (Parent->isAnonymousStructOrUnion() || Parent->isUnion()) {
5273  if (Parent->isUnion()) {
5274  UnionEntry &En = Unions[Parent];
5275  if (En.first && En.first != Child) {
5276  S.Diag(Init->getSourceLocation(),
5277  diag::err_multiple_mem_union_initialization)
5278  << Field->getDeclName()
5279  << Init->getSourceRange();
5280  S.Diag(En.second->getSourceLocation(), diag::note_previous_initializer)
5281  << 0 << En.second->getSourceRange();
5282  return true;
5283  }
5284  if (!En.first) {
5285  En.first = Child;
5286  En.second = Init;
5287  }
5288  if (!Parent->isAnonymousStructOrUnion())
5289  return false;
5290  }
5291 
5292  Child = Parent;
5293  Parent = cast<RecordDecl>(Parent->getDeclContext());
5294  }
5295 
5296  return false;
5297 }
5298 }
5299 
5300 /// ActOnMemInitializers - Handle the member initializers for a constructor.
5301 void Sema::ActOnMemInitializers(Decl *ConstructorDecl,
5304  bool AnyErrors) {
5305  if (!ConstructorDecl)
5306  return;
5307 
5308  AdjustDeclIfTemplate(ConstructorDecl);
5309 
5310  CXXConstructorDecl *Constructor
5311  = dyn_cast<CXXConstructorDecl>(ConstructorDecl);
5312 
5313  if (!Constructor) {
5314  Diag(ColonLoc, diag::err_only_constructors_take_base_inits);
5315  return;
5316  }
5317 
5318  // Mapping for the duplicate initializers check.
5319  // For member initializers, this is keyed with a FieldDecl*.
5320  // For base initializers, this is keyed with a Type*.
5321  llvm::DenseMap<const void *, CXXCtorInitializer *> Members;
5322 
5323  // Mapping for the inconsistent anonymous-union initializers check.
5324  RedundantUnionMap MemberUnions;
5325 
5326  bool HadError = false;
5327  for (unsigned i = 0; i < MemInits.size(); i++) {
5328  CXXCtorInitializer *Init = MemInits[i];
5329 
5330  // Set the source order index.
5331  Init->setSourceOrder(i);
5332 
5333  if (Init->isAnyMemberInitializer()) {
5334  const void *Key = GetKeyForMember(Context, Init);
5335  if (CheckRedundantInit(*this, Init, Members[Key]) ||
5336  CheckRedundantUnionInit(*this, Init, MemberUnions))
5337  HadError = true;
5338  } else if (Init->isBaseInitializer()) {
5339  const void *Key = GetKeyForMember(Context, Init);
5340  if (CheckRedundantInit(*this, Init, Members[Key]))
5341  HadError = true;
5342  } else {
5343  assert(Init->isDelegatingInitializer());
5344  // This must be the only initializer
5345  if (MemInits.size() != 1) {
5346  Diag(Init->getSourceLocation(),
5347  diag::err_delegating_initializer_alone)
5348  << Init->getSourceRange() << MemInits[i ? 0 : 1]->getSourceRange();
5349  // We will treat this as being the only initializer.
5350  }
5351  SetDelegatingInitializer(Constructor, MemInits[i]);
5352  // Return immediately as the initializer is set.
5353  return;
5354  }
5355  }
5356 
5357  if (HadError)
5358  return;
5359 
5360  DiagnoseBaseOrMemInitializerOrder(*this, Constructor, MemInits);
5361 
5362  SetCtorInitializers(Constructor, AnyErrors, MemInits);
5363 
5364  DiagnoseUninitializedFields(*this, Constructor);
5365 }
5366 
5367 void
5369  CXXRecordDecl *ClassDecl) {
5370  // Ignore dependent contexts. Also ignore unions, since their members never
5371  // have destructors implicitly called.
5372  if (ClassDecl->isDependentContext() || ClassDecl->isUnion())
5373  return;
5374 
5375  // FIXME: all the access-control diagnostics are positioned on the
5376  // field/base declaration. That's probably good; that said, the
5377  // user might reasonably want to know why the destructor is being
5378  // emitted, and we currently don't say.
5379 
5380  // Non-static data members.
5381  for (auto *Field : ClassDecl->fields()) {
5382  if (Field->isInvalidDecl())
5383  continue;
5384 
5385  // Don't destroy incomplete or zero-length arrays.
5386  if (isIncompleteOrZeroLengthArrayType(Context, Field->getType()))
5387  continue;
5388 
5389  QualType FieldType = Context.getBaseElementType(Field->getType());
5390 
5391  const RecordType* RT = FieldType->getAs<RecordType>();
5392  if (!RT)
5393  continue;
5394 
5395  CXXRecordDecl *FieldClassDecl = cast<CXXRecordDecl>(RT->getDecl());
5396  if (FieldClassDecl->isInvalidDecl())
5397  continue;
5398  if (FieldClassDecl->hasIrrelevantDestructor())
5399  continue;
5400  // The destructor for an implicit anonymous union member is never invoked.
5401  if (FieldClassDecl->isUnion() && FieldClassDecl->isAnonymousStructOrUnion())
5402  continue;
5403 
5404  CXXDestructorDecl *Dtor = LookupDestructor(FieldClassDecl);
5405  assert(Dtor && "No dtor found for FieldClassDecl!");
5406  CheckDestructorAccess(Field->getLocation(), Dtor,
5407  PDiag(diag::err_access_dtor_field)
5408  << Field->getDeclName()
5409  << FieldType);
5410 
5411  MarkFunctionReferenced(Location, Dtor);
5412  DiagnoseUseOfDecl(Dtor, Location);
5413  }
5414 
5415  // We only potentially invoke the destructors of potentially constructed
5416  // subobjects.
5417  bool VisitVirtualBases = !ClassDecl->isAbstract();
5418 
5419  llvm::SmallPtrSet<const RecordType *, 8> DirectVirtualBases;
5420 
5421  // Bases.
5422  for (const auto &Base : ClassDecl->bases()) {
5423  // Bases are always records in a well-formed non-dependent class.
5424  const RecordType *RT = Base.getType()->getAs<RecordType>();
5425 
5426  // Remember direct virtual bases.
5427  if (Base.isVirtual()) {
5428  if (!VisitVirtualBases)
5429  continue;
5430  DirectVirtualBases.insert(RT);
5431  }
5432 
5433  CXXRecordDecl *BaseClassDecl = cast<CXXRecordDecl>(RT->getDecl());
5434  // If our base class is invalid, we probably can't get its dtor anyway.
5435  if (BaseClassDecl->isInvalidDecl())
5436  continue;
5437  if (BaseClassDecl->hasIrrelevantDestructor())
5438  continue;
5439 
5440  CXXDestructorDecl *Dtor = LookupDestructor(BaseClassDecl);
5441  assert(Dtor && "No dtor found for BaseClassDecl!");
5442 
5443  // FIXME: caret should be on the start of the class name
5444  CheckDestructorAccess(Base.getBeginLoc(), Dtor,
5445  PDiag(diag::err_access_dtor_base)
5446  << Base.getType() << Base.getSourceRange(),
5447  Context.getTypeDeclType(ClassDecl));
5448 
5449  MarkFunctionReferenced(Location, Dtor);
5450  DiagnoseUseOfDecl(Dtor, Location);
5451  }
5452 
5453  if (!VisitVirtualBases)
5454  return;
5455 
5456  // Virtual bases.
5457  for (const auto &VBase : ClassDecl->vbases()) {
5458  // Bases are always records in a well-formed non-dependent class.
5459  const RecordType *RT = VBase.getType()->castAs<RecordType>();
5460 
5461  // Ignore direct virtual bases.
5462  if (DirectVirtualBases.count(RT))
5463  continue;
5464 
5465  CXXRecordDecl *BaseClassDecl = cast<CXXRecordDecl>(RT->getDecl());
5466  // If our base class is invalid, we probably can't get its dtor anyway.
5467  if (BaseClassDecl->isInvalidDecl())
5468  continue;
5469  if (BaseClassDecl->hasIrrelevantDestructor())
5470  continue;
5471 
5472  CXXDestructorDecl *Dtor = LookupDestructor(BaseClassDecl);
5473  assert(Dtor && "No dtor found for BaseClassDecl!");
5474  if (CheckDestructorAccess(
5475  ClassDecl->getLocation(), Dtor,
5476  PDiag(diag::err_access_dtor_vbase)
5477  << Context.getTypeDeclType(ClassDecl) << VBase.getType(),
5478  Context.getTypeDeclType(ClassDecl)) ==
5479  AR_accessible) {
5480  CheckDerivedToBaseConversion(
5481  Context.getTypeDeclType(ClassDecl), VBase.getType(),
5482  diag::err_access_dtor_vbase, 0, ClassDecl->getLocation(),
5483  SourceRange(), DeclarationName(), nullptr);
5484  }
5485 
5486  MarkFunctionReferenced(Location, Dtor);
5487  DiagnoseUseOfDecl(Dtor, Location);
5488  }
5489 }
5490 
5491 void Sema::ActOnDefaultCtorInitializers(Decl *CDtorDecl) {
5492  if (!CDtorDecl)
5493  return;
5494 
5495  if (CXXConstructorDecl *Constructor
5496  = dyn_cast<CXXConstructorDecl>(CDtorDecl)) {
5497  SetCtorInitializers(Constructor, /*AnyErrors=*/false);
5498  DiagnoseUninitializedFields(*this, Constructor);
5499  }
5500 }
5501 
5503  if (!getLangOpts().CPlusPlus)
5504  return false;
5505 
5506  const auto *RD = Context.getBaseElementType(T)->getAsCXXRecordDecl();
5507  if (!RD)
5508  return false;
5509 
5510  // FIXME: Per [temp.inst]p1, we are supposed to trigger instantiation of a
5511  // class template specialization here, but doing so breaks a lot of code.
5512 
5513  // We can't answer whether something is abstract until it has a
5514  // definition. If it's currently being defined, we'll walk back
5515  // over all the declarations when we have a full definition.
5516  const CXXRecordDecl *Def = RD->getDefinition();
5517  if (!Def || Def->isBeingDefined())
5518  return false;
5519 
5520  return RD->isAbstract();
5521 }
5522 
5524  TypeDiagnoser &Diagnoser) {
5525  if (!isAbstractType(Loc, T))
5526  return false;
5527 
5528  T = Context.getBaseElementType(T);
5529  Diagnoser.diagnose(*this, Loc, T);
5530  DiagnoseAbstractType(T->getAsCXXRecordDecl());
5531  return true;
5532 }
5533 
5535  // Check if we've already emitted the list of pure virtual functions
5536  // for this class.
5537  if (PureVirtualClassDiagSet && PureVirtualClassDiagSet->count(RD))
5538  return;
5539 
5540  // If the diagnostic is suppressed, don't emit the notes. We're only
5541  // going to emit them once, so try to attach them to a diagnostic we're
5542  // actually going to show.
5543  if (Diags.isLastDiagnosticIgnored())
5544  return;
5545 
5546  CXXFinalOverriderMap FinalOverriders;
5547  RD->getFinalOverriders(FinalOverriders);
5548 
5549  // Keep a set of seen pure methods so we won't diagnose the same method
5550  // more than once.
5551  llvm::SmallPtrSet<const CXXMethodDecl *, 8> SeenPureMethods;
5552 
5553  for (CXXFinalOverriderMap::iterator M = FinalOverriders.begin(),
5554  MEnd = FinalOverriders.end();
5555  M != MEnd;
5556  ++M) {
5557  for (OverridingMethods::iterator SO = M->second.begin(),
5558  SOEnd = M->second.end();
5559  SO != SOEnd; ++SO) {
5560  // C++ [class.abstract]p4:
5561  // A class is abstract if it contains or inherits at least one
5562  // pure virtual function for which the final overrider is pure
5563  // virtual.
5564 
5565  //
5566  if (SO->second.size() != 1)
5567  continue;
5568 
5569  if (!SO->second.front().Method->isPure())
5570  continue;
5571 
5572  if (!SeenPureMethods.insert(SO->second.front().Method).second)
5573  continue;
5574 
5575  Diag(SO->second.front().Method->getLocation(),
5576  diag::note_pure_virtual_function)
5577  << SO->second.front().Method->getDeclName() << RD->getDeclName();
5578  }
5579  }
5580 
5581  if (!PureVirtualClassDiagSet)
5582  PureVirtualClassDiagSet.reset(new RecordDeclSetTy);
5583  PureVirtualClassDiagSet->insert(RD);
5584 }
5585 
5586 namespace {
5587 struct AbstractUsageInfo {
5588  Sema &S;
5589  CXXRecordDecl *Record;
5590  CanQualType AbstractType;
5591  bool Invalid;
5592 
5593  AbstractUsageInfo(Sema &S, CXXRecordDecl *Record)
5594  : S(S), Record(Record),
5595  AbstractType(S.Context.getCanonicalType(
5596  S.Context.getTypeDeclType(Record))),
5597  Invalid(false) {}
5598 
5599  void DiagnoseAbstractType() {
5600  if (Invalid) return;
5601  S.DiagnoseAbstractType(Record);
5602  Invalid = true;
5603  }
5604 
5605  void CheckType(const NamedDecl *D, TypeLoc TL, Sema::AbstractDiagSelID Sel);
5606 };
5607 
5608 struct CheckAbstractUsage {
5609  AbstractUsageInfo &Info;
5610  const NamedDecl *Ctx;
5611 
5612  CheckAbstractUsage(AbstractUsageInfo &Info, const NamedDecl *Ctx)
5613  : Info(Info), Ctx(Ctx) {}
5614 
5615  void Visit(TypeLoc TL, Sema::AbstractDiagSelID Sel) {
5616  switch (TL.getTypeLocClass()) {
5617 #define ABSTRACT_TYPELOC(CLASS, PARENT)
5618 #define TYPELOC(CLASS, PARENT) \
5619  case TypeLoc::CLASS: Check(TL.castAs<CLASS##TypeLoc>(), Sel); break;
5620 #include "clang/AST/TypeLocNodes.def"
5621  }
5622  }
5623 
5624  void Check(FunctionProtoTypeLoc TL, Sema::AbstractDiagSelID Sel) {
5626  for (unsigned I = 0, E = TL.getNumParams(); I != E; ++I) {
5627  if (!TL.getParam(I))
5628  continue;
5629 
5630  TypeSourceInfo *TSI = TL.getParam(I)->getTypeSourceInfo();
5631  if (TSI) Visit(TSI->getTypeLoc(), Sema::AbstractParamType);
5632  }
5633  }
5634 
5635  void Check(ArrayTypeLoc TL, Sema::AbstractDiagSelID Sel) {
5637  }
5638 
5640  // Visit the type parameters from a permissive context.
5641  for (unsigned I = 0, E = TL.getNumArgs(); I != E; ++I) {
5642  TemplateArgumentLoc TAL = TL.getArgLoc(I);
5644  if (TypeSourceInfo *TSI = TAL.getTypeSourceInfo())
5645  Visit(TSI->getTypeLoc(), Sema::AbstractNone);
5646  // TODO: other template argument types?
5647  }
5648  }
5649 
5650  // Visit pointee types from a permissive context.
5651 #define CheckPolymorphic(Type) \
5652  void Check(Type TL, Sema::AbstractDiagSelID Sel) { \
5653  Visit(TL.getNextTypeLoc(), Sema::AbstractNone); \
5654  }
5660 
5661  /// Handle all the types we haven't given a more specific
5662  /// implementation for above.
5663  void Check(TypeLoc TL, Sema::AbstractDiagSelID Sel) {
5664  // Every other kind of type that we haven't called out already
5665  // that has an inner type is either (1) sugar or (2) contains that
5666  // inner type in some way as a subobject.
5667  if (TypeLoc Next = TL.getNextTypeLoc())
5668  return Visit(Next, Sel);
5669 
5670  // If there's no inner type and we're in a permissive context,
5671  // don't diagnose.
5672  if (Sel == Sema::AbstractNone) return;
5673 
5674  // Check whether the type matches the abstract type.
5675  QualType T = TL.getType();
5676  if (T->isArrayType()) {
5678  T = Info.S.Context.getBaseElementType(T);
5679  }
5681  if (CT != Info.AbstractType) return;
5682 
5683