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SemaDeclCXX.cpp
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1 //===------ SemaDeclCXX.cpp - Semantic Analysis for C++ Declarations ------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file implements semantic analysis for C++ declarations.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "clang/AST/ASTConsumer.h"
15 #include "clang/AST/ASTContext.h"
16 #include "clang/AST/ASTLambda.h"
19 #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"
28 #include "clang/Basic/TargetInfo.h"
30 #include "clang/Lex/Preprocessor.h"
32 #include "clang/Sema/DeclSpec.h"
34 #include "clang/Sema/Lookup.h"
36 #include "clang/Sema/Scope.h"
37 #include "clang/Sema/ScopeInfo.h"
39 #include "clang/Sema/Template.h"
40 #include "llvm/ADT/STLExtras.h"
41 #include "llvm/ADT/SmallString.h"
42 #include "llvm/ADT/StringExtras.h"
43 #include <map>
44 #include <set>
45 
46 using namespace clang;
47 
48 //===----------------------------------------------------------------------===//
49 // CheckDefaultArgumentVisitor
50 //===----------------------------------------------------------------------===//
51 
52 namespace {
53  /// CheckDefaultArgumentVisitor - C++ [dcl.fct.default] Traverses
54  /// the default argument of a parameter to determine whether it
55  /// contains any ill-formed subexpressions. For example, this will
56  /// diagnose the use of local variables or parameters within the
57  /// default argument expression.
58  class CheckDefaultArgumentVisitor
59  : public StmtVisitor<CheckDefaultArgumentVisitor, bool> {
60  Expr *DefaultArg;
61  Sema *S;
62 
63  public:
64  CheckDefaultArgumentVisitor(Expr *defarg, Sema *s)
65  : DefaultArg(defarg), S(s) {}
66 
67  bool VisitExpr(Expr *Node);
68  bool VisitDeclRefExpr(DeclRefExpr *DRE);
69  bool VisitCXXThisExpr(CXXThisExpr *ThisE);
70  bool VisitLambdaExpr(LambdaExpr *Lambda);
71  bool VisitPseudoObjectExpr(PseudoObjectExpr *POE);
72  };
73 
74  /// VisitExpr - Visit all of the children of this expression.
75  bool CheckDefaultArgumentVisitor::VisitExpr(Expr *Node) {
76  bool IsInvalid = false;
77  for (Stmt *SubStmt : Node->children())
78  IsInvalid |= Visit(SubStmt);
79  return IsInvalid;
80  }
81 
82  /// VisitDeclRefExpr - Visit a reference to a declaration, to
83  /// determine whether this declaration can be used in the default
84  /// argument expression.
85  bool CheckDefaultArgumentVisitor::VisitDeclRefExpr(DeclRefExpr *DRE) {
86  NamedDecl *Decl = DRE->getDecl();
87  if (ParmVarDecl *Param = dyn_cast<ParmVarDecl>(Decl)) {
88  // C++ [dcl.fct.default]p9
89  // Default arguments are evaluated each time the function is
90  // called. The order of evaluation of function arguments is
91  // unspecified. Consequently, parameters of a function shall not
92  // be used in default argument expressions, even if they are not
93  // evaluated. Parameters of a function declared before a default
94  // argument expression are in scope and can hide namespace and
95  // class member names.
96  return S->Diag(DRE->getLocStart(),
97  diag::err_param_default_argument_references_param)
98  << Param->getDeclName() << DefaultArg->getSourceRange();
99  } else if (VarDecl *VDecl = dyn_cast<VarDecl>(Decl)) {
100  // C++ [dcl.fct.default]p7
101  // Local variables shall not be used in default argument
102  // expressions.
103  if (VDecl->isLocalVarDecl())
104  return S->Diag(DRE->getLocStart(),
105  diag::err_param_default_argument_references_local)
106  << VDecl->getDeclName() << DefaultArg->getSourceRange();
107  }
108 
109  return false;
110  }
111 
112  /// VisitCXXThisExpr - Visit a C++ "this" expression.
113  bool CheckDefaultArgumentVisitor::VisitCXXThisExpr(CXXThisExpr *ThisE) {
114  // C++ [dcl.fct.default]p8:
115  // The keyword this shall not be used in a default argument of a
116  // member function.
117  return S->Diag(ThisE->getLocStart(),
118  diag::err_param_default_argument_references_this)
119  << ThisE->getSourceRange();
120  }
121 
122  bool CheckDefaultArgumentVisitor::VisitPseudoObjectExpr(PseudoObjectExpr *POE) {
123  bool Invalid = false;
125  i = POE->semantics_begin(), e = POE->semantics_end(); i != e; ++i) {
126  Expr *E = *i;
127 
128  // Look through bindings.
129  if (OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(E)) {
130  E = OVE->getSourceExpr();
131  assert(E && "pseudo-object binding without source expression?");
132  }
133 
134  Invalid |= Visit(E);
135  }
136  return Invalid;
137  }
138 
139  bool CheckDefaultArgumentVisitor::VisitLambdaExpr(LambdaExpr *Lambda) {
140  // C++11 [expr.lambda.prim]p13:
141  // A lambda-expression appearing in a default argument shall not
142  // implicitly or explicitly capture any entity.
143  if (Lambda->capture_begin() == Lambda->capture_end())
144  return false;
145 
146  return S->Diag(Lambda->getLocStart(),
147  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  // If this function can throw any exceptions, make a note of that.
175  case EST_MSAny:
176  case EST_None:
177  ClearExceptions();
178  ComputedEST = EST;
179  return;
180  // FIXME: If the call to this decl is using any of its default arguments, we
181  // need to search them for potentially-throwing calls.
182  // If this function has a basic noexcept, it doesn't affect the outcome.
183  case EST_BasicNoexcept:
184  return;
185  // If we're still at noexcept(true) and there's a nothrow() callee,
186  // change to that specification.
187  case EST_DynamicNone:
188  if (ComputedEST == EST_BasicNoexcept)
189  ComputedEST = EST_DynamicNone;
190  return;
191  // Check out noexcept specs.
193  {
195  Proto->getNoexceptSpec(Self->Context);
196  assert(NR != FunctionProtoType::NR_NoNoexcept &&
197  "Must have noexcept result for EST_ComputedNoexcept.");
198  assert(NR != FunctionProtoType::NR_Dependent &&
199  "Should not generate implicit declarations for dependent cases, "
200  "and don't know how to handle them anyway.");
201  // noexcept(false) -> no spec on the new function
202  if (NR == FunctionProtoType::NR_Throw) {
203  ClearExceptions();
204  ComputedEST = EST_None;
205  }
206  // noexcept(true) won't change anything either.
207  return;
208  }
209  default:
210  break;
211  }
212  assert(EST == EST_Dynamic && "EST case not considered earlier.");
213  assert(ComputedEST != EST_None &&
214  "Shouldn't collect exceptions when throw-all is guaranteed.");
215  ComputedEST = EST_Dynamic;
216  // Record the exceptions in this function's exception specification.
217  for (const auto &E : Proto->exceptions())
218  if (ExceptionsSeen.insert(Self->Context.getCanonicalType(E)).second)
219  Exceptions.push_back(E);
220 }
221 
223  if (!E || ComputedEST == EST_MSAny)
224  return;
225 
226  // FIXME:
227  //
228  // C++0x [except.spec]p14:
229  // [An] implicit exception-specification specifies the type-id T if and
230  // only if T is allowed by the exception-specification of a function directly
231  // invoked by f's implicit definition; f shall allow all exceptions if any
232  // function it directly invokes allows all exceptions, and f shall allow no
233  // exceptions if every function it directly invokes allows no exceptions.
234  //
235  // Note in particular that if an implicit exception-specification is generated
236  // for a function containing a throw-expression, that specification can still
237  // be noexcept(true).
238  //
239  // Note also that 'directly invoked' is not defined in the standard, and there
240  // is no indication that we should only consider potentially-evaluated calls.
241  //
242  // Ultimately we should implement the intent of the standard: the exception
243  // specification should be the set of exceptions which can be thrown by the
244  // implicit definition. For now, we assume that any non-nothrow expression can
245  // throw any exception.
246 
247  if (Self->canThrow(E))
248  ComputedEST = EST_None;
249 }
250 
251 bool
253  SourceLocation EqualLoc) {
254  if (RequireCompleteType(Param->getLocation(), Param->getType(),
255  diag::err_typecheck_decl_incomplete_type)) {
256  Param->setInvalidDecl();
257  return true;
258  }
259 
260  // C++ [dcl.fct.default]p5
261  // A default argument expression is implicitly converted (clause
262  // 4) to the parameter type. The default argument expression has
263  // the same semantic constraints as the initializer expression in
264  // a declaration of a variable of the parameter type, using the
265  // copy-initialization semantics (8.5).
267  Param);
269  EqualLoc);
270  InitializationSequence InitSeq(*this, Entity, Kind, Arg);
271  ExprResult Result = InitSeq.Perform(*this, Entity, Kind, Arg);
272  if (Result.isInvalid())
273  return true;
274  Arg = Result.getAs<Expr>();
275 
276  CheckCompletedExpr(Arg, EqualLoc);
277  Arg = MaybeCreateExprWithCleanups(Arg);
278 
279  // Okay: add the default argument to the parameter
280  Param->setDefaultArg(Arg);
281 
282  // We have already instantiated this parameter; provide each of the
283  // instantiations with the uninstantiated default argument.
284  UnparsedDefaultArgInstantiationsMap::iterator InstPos
285  = UnparsedDefaultArgInstantiations.find(Param);
286  if (InstPos != UnparsedDefaultArgInstantiations.end()) {
287  for (unsigned I = 0, N = InstPos->second.size(); I != N; ++I)
288  InstPos->second[I]->setUninstantiatedDefaultArg(Arg);
289 
290  // We're done tracking this parameter's instantiations.
291  UnparsedDefaultArgInstantiations.erase(InstPos);
292  }
293 
294  return false;
295 }
296 
297 /// ActOnParamDefaultArgument - Check whether the default argument
298 /// provided for a function parameter is well-formed. If so, attach it
299 /// to the parameter declaration.
300 void
302  Expr *DefaultArg) {
303  if (!param || !DefaultArg)
304  return;
305 
306  ParmVarDecl *Param = cast<ParmVarDecl>(param);
307  UnparsedDefaultArgLocs.erase(Param);
308 
309  // Default arguments are only permitted in C++
310  if (!getLangOpts().CPlusPlus) {
311  Diag(EqualLoc, diag::err_param_default_argument)
312  << DefaultArg->getSourceRange();
313  Param->setInvalidDecl();
314  return;
315  }
316 
317  // Check for unexpanded parameter packs.
318  if (DiagnoseUnexpandedParameterPack(DefaultArg, UPPC_DefaultArgument)) {
319  Param->setInvalidDecl();
320  return;
321  }
322 
323  // C++11 [dcl.fct.default]p3
324  // A default argument expression [...] shall not be specified for a
325  // parameter pack.
326  if (Param->isParameterPack()) {
327  Diag(EqualLoc, diag::err_param_default_argument_on_parameter_pack)
328  << DefaultArg->getSourceRange();
329  return;
330  }
331 
332  // Check that the default argument is well-formed
333  CheckDefaultArgumentVisitor DefaultArgChecker(DefaultArg, this);
334  if (DefaultArgChecker.Visit(DefaultArg)) {
335  Param->setInvalidDecl();
336  return;
337  }
338 
339  SetParamDefaultArgument(Param, DefaultArg, EqualLoc);
340 }
341 
342 /// ActOnParamUnparsedDefaultArgument - We've seen a default
343 /// argument for a function parameter, but we can't parse it yet
344 /// because we're inside a class definition. Note that this default
345 /// argument will be parsed later.
347  SourceLocation EqualLoc,
348  SourceLocation ArgLoc) {
349  if (!param)
350  return;
351 
352  ParmVarDecl *Param = cast<ParmVarDecl>(param);
353  Param->setUnparsedDefaultArg();
354  UnparsedDefaultArgLocs[Param] = ArgLoc;
355 }
356 
357 /// ActOnParamDefaultArgumentError - Parsing or semantic analysis of
358 /// the default argument for the parameter param failed.
360  SourceLocation EqualLoc) {
361  if (!param)
362  return;
363 
364  ParmVarDecl *Param = cast<ParmVarDecl>(param);
365  Param->setInvalidDecl();
366  UnparsedDefaultArgLocs.erase(Param);
367  Param->setDefaultArg(new(Context)
368  OpaqueValueExpr(EqualLoc,
369  Param->getType().getNonReferenceType(),
370  VK_RValue));
371 }
372 
373 /// CheckExtraCXXDefaultArguments - Check for any extra default
374 /// arguments in the declarator, which is not a function declaration
375 /// or definition and therefore is not permitted to have default
376 /// arguments. This routine should be invoked for every declarator
377 /// that is not a function declaration or definition.
379  // C++ [dcl.fct.default]p3
380  // A default argument expression shall be specified only in the
381  // parameter-declaration-clause of a function declaration or in a
382  // template-parameter (14.1). It shall not be specified for a
383  // parameter pack. If it is specified in a
384  // parameter-declaration-clause, it shall not occur within a
385  // declarator or abstract-declarator of a parameter-declaration.
386  bool MightBeFunction = D.isFunctionDeclarationContext();
387  for (unsigned i = 0, e = D.getNumTypeObjects(); i != e; ++i) {
388  DeclaratorChunk &chunk = D.getTypeObject(i);
389  if (chunk.Kind == DeclaratorChunk::Function) {
390  if (MightBeFunction) {
391  // This is a function declaration. It can have default arguments, but
392  // keep looking in case its return type is a function type with default
393  // arguments.
394  MightBeFunction = false;
395  continue;
396  }
397  for (unsigned argIdx = 0, e = chunk.Fun.NumParams; argIdx != e;
398  ++argIdx) {
399  ParmVarDecl *Param = cast<ParmVarDecl>(chunk.Fun.Params[argIdx].Param);
400  if (Param->hasUnparsedDefaultArg()) {
401  std::unique_ptr<CachedTokens> Toks =
402  std::move(chunk.Fun.Params[argIdx].DefaultArgTokens);
403  SourceRange SR;
404  if (Toks->size() > 1)
405  SR = SourceRange((*Toks)[1].getLocation(),
406  Toks->back().getLocation());
407  else
408  SR = UnparsedDefaultArgLocs[Param];
409  Diag(Param->getLocation(), diag::err_param_default_argument_nonfunc)
410  << SR;
411  } else if (Param->getDefaultArg()) {
412  Diag(Param->getLocation(), diag::err_param_default_argument_nonfunc)
413  << Param->getDefaultArg()->getSourceRange();
414  Param->setDefaultArg(nullptr);
415  }
416  }
417  } else if (chunk.Kind != DeclaratorChunk::Paren) {
418  MightBeFunction = false;
419  }
420  }
421 }
422 
424  for (unsigned NumParams = FD->getNumParams(); NumParams > 0; --NumParams) {
425  const ParmVarDecl *PVD = FD->getParamDecl(NumParams-1);
426  if (!PVD->hasDefaultArg())
427  return false;
428  if (!PVD->hasInheritedDefaultArg())
429  return true;
430  }
431  return false;
432 }
433 
434 /// MergeCXXFunctionDecl - Merge two declarations of the same C++
435 /// function, once we already know that they have the same
436 /// type. Subroutine of MergeFunctionDecl. Returns true if there was an
437 /// error, false otherwise.
439  Scope *S) {
440  bool Invalid = false;
441 
442  // The declaration context corresponding to the scope is the semantic
443  // parent, unless this is a local function declaration, in which case
444  // it is that surrounding function.
445  DeclContext *ScopeDC = New->isLocalExternDecl()
446  ? New->getLexicalDeclContext()
447  : New->getDeclContext();
448 
449  // Find the previous declaration for the purpose of default arguments.
450  FunctionDecl *PrevForDefaultArgs = Old;
451  for (/**/; PrevForDefaultArgs;
452  // Don't bother looking back past the latest decl if this is a local
453  // extern declaration; nothing else could work.
454  PrevForDefaultArgs = New->isLocalExternDecl()
455  ? nullptr
456  : PrevForDefaultArgs->getPreviousDecl()) {
457  // Ignore hidden declarations.
458  if (!LookupResult::isVisible(*this, PrevForDefaultArgs))
459  continue;
460 
461  if (S && !isDeclInScope(PrevForDefaultArgs, ScopeDC, S) &&
462  !New->isCXXClassMember()) {
463  // Ignore default arguments of old decl if they are not in
464  // the same scope and this is not an out-of-line definition of
465  // a member function.
466  continue;
467  }
468 
469  if (PrevForDefaultArgs->isLocalExternDecl() != New->isLocalExternDecl()) {
470  // If only one of these is a local function declaration, then they are
471  // declared in different scopes, even though isDeclInScope may think
472  // they're in the same scope. (If both are local, the scope check is
473  // sufficient, and if neither is local, then they are in the same scope.)
474  continue;
475  }
476 
477  // We found the right previous declaration.
478  break;
479  }
480 
481  // C++ [dcl.fct.default]p4:
482  // For non-template functions, default arguments can be added in
483  // later declarations of a function in the same
484  // scope. Declarations in different scopes have completely
485  // distinct sets of default arguments. That is, declarations in
486  // inner scopes do not acquire default arguments from
487  // declarations in outer scopes, and vice versa. In a given
488  // function declaration, all parameters subsequent to a
489  // parameter with a default argument shall have default
490  // arguments supplied in this or previous declarations. A
491  // default argument shall not be redefined by a later
492  // declaration (not even to the same value).
493  //
494  // C++ [dcl.fct.default]p6:
495  // Except for member functions of class templates, the default arguments
496  // in a member function definition that appears outside of the class
497  // definition are added to the set of default arguments provided by the
498  // member function declaration in the class definition.
499  for (unsigned p = 0, NumParams = PrevForDefaultArgs
500  ? PrevForDefaultArgs->getNumParams()
501  : 0;
502  p < NumParams; ++p) {
503  ParmVarDecl *OldParam = PrevForDefaultArgs->getParamDecl(p);
504  ParmVarDecl *NewParam = New->getParamDecl(p);
505 
506  bool OldParamHasDfl = OldParam ? OldParam->hasDefaultArg() : false;
507  bool NewParamHasDfl = NewParam->hasDefaultArg();
508 
509  if (OldParamHasDfl && NewParamHasDfl) {
510  unsigned DiagDefaultParamID =
511  diag::err_param_default_argument_redefinition;
512 
513  // MSVC accepts that default parameters be redefined for member functions
514  // of template class. The new default parameter's value is ignored.
515  Invalid = true;
516  if (getLangOpts().MicrosoftExt) {
517  CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(New);
518  if (MD && MD->getParent()->getDescribedClassTemplate()) {
519  // Merge the old default argument into the new parameter.
520  NewParam->setHasInheritedDefaultArg();
521  if (OldParam->hasUninstantiatedDefaultArg())
522  NewParam->setUninstantiatedDefaultArg(
523  OldParam->getUninstantiatedDefaultArg());
524  else
525  NewParam->setDefaultArg(OldParam->getInit());
526  DiagDefaultParamID = diag::ext_param_default_argument_redefinition;
527  Invalid = false;
528  }
529  }
530 
531  // FIXME: If we knew where the '=' was, we could easily provide a fix-it
532  // hint here. Alternatively, we could walk the type-source information
533  // for NewParam to find the last source location in the type... but it
534  // isn't worth the effort right now. This is the kind of test case that
535  // is hard to get right:
536  // int f(int);
537  // void g(int (*fp)(int) = f);
538  // void g(int (*fp)(int) = &f);
539  Diag(NewParam->getLocation(), DiagDefaultParamID)
540  << NewParam->getDefaultArgRange();
541 
542  // Look for the function declaration where the default argument was
543  // actually written, which may be a declaration prior to Old.
544  for (auto Older = PrevForDefaultArgs;
545  OldParam->hasInheritedDefaultArg(); /**/) {
546  Older = Older->getPreviousDecl();
547  OldParam = Older->getParamDecl(p);
548  }
549 
550  Diag(OldParam->getLocation(), diag::note_previous_definition)
551  << OldParam->getDefaultArgRange();
552  } else if (OldParamHasDfl) {
553  // Merge the old default argument into the new parameter unless the new
554  // function is a friend declaration in a template class. In the latter
555  // case the default arguments will be inherited when the friend
556  // declaration will be instantiated.
557  if (New->getFriendObjectKind() == Decl::FOK_None ||
559  // It's important to use getInit() here; getDefaultArg()
560  // strips off any top-level ExprWithCleanups.
561  NewParam->setHasInheritedDefaultArg();
562  if (OldParam->hasUnparsedDefaultArg())
563  NewParam->setUnparsedDefaultArg();
564  else if (OldParam->hasUninstantiatedDefaultArg())
565  NewParam->setUninstantiatedDefaultArg(
566  OldParam->getUninstantiatedDefaultArg());
567  else
568  NewParam->setDefaultArg(OldParam->getInit());
569  }
570  } else if (NewParamHasDfl) {
571  if (New->getDescribedFunctionTemplate()) {
572  // Paragraph 4, quoted above, only applies to non-template functions.
573  Diag(NewParam->getLocation(),
574  diag::err_param_default_argument_template_redecl)
575  << NewParam->getDefaultArgRange();
576  Diag(PrevForDefaultArgs->getLocation(),
577  diag::note_template_prev_declaration)
578  << false;
579  } else if (New->getTemplateSpecializationKind()
582  // C++ [temp.expr.spec]p21:
583  // Default function arguments shall not be specified in a declaration
584  // or a definition for one of the following explicit specializations:
585  // - the explicit specialization of a function template;
586  // - the explicit specialization of a member function template;
587  // - the explicit specialization of a member function of a class
588  // template where the class template specialization to which the
589  // member function specialization belongs is implicitly
590  // instantiated.
591  Diag(NewParam->getLocation(), diag::err_template_spec_default_arg)
593  << New->getDeclName()
594  << NewParam->getDefaultArgRange();
595  } else if (New->getDeclContext()->isDependentContext()) {
596  // C++ [dcl.fct.default]p6 (DR217):
597  // Default arguments for a member function of a class template shall
598  // be specified on the initial declaration of the member function
599  // within the class template.
600  //
601  // Reading the tea leaves a bit in DR217 and its reference to DR205
602  // leads me to the conclusion that one cannot add default function
603  // arguments for an out-of-line definition of a member function of a
604  // dependent type.
605  int WhichKind = 2;
606  if (CXXRecordDecl *Record
607  = dyn_cast<CXXRecordDecl>(New->getDeclContext())) {
608  if (Record->getDescribedClassTemplate())
609  WhichKind = 0;
610  else if (isa<ClassTemplatePartialSpecializationDecl>(Record))
611  WhichKind = 1;
612  else
613  WhichKind = 2;
614  }
615 
616  Diag(NewParam->getLocation(),
617  diag::err_param_default_argument_member_template_redecl)
618  << WhichKind
619  << NewParam->getDefaultArgRange();
620  }
621  }
622  }
623 
624  // DR1344: If a default argument is added outside a class definition and that
625  // default argument makes the function a special member function, the program
626  // is ill-formed. This can only happen for constructors.
627  if (isa<CXXConstructorDecl>(New) &&
629  CXXSpecialMember NewSM = getSpecialMember(cast<CXXMethodDecl>(New)),
630  OldSM = getSpecialMember(cast<CXXMethodDecl>(Old));
631  if (NewSM != OldSM) {
632  ParmVarDecl *NewParam = New->getParamDecl(New->getMinRequiredArguments());
633  assert(NewParam->hasDefaultArg());
634  Diag(NewParam->getLocation(), diag::err_default_arg_makes_ctor_special)
635  << NewParam->getDefaultArgRange() << NewSM;
636  Diag(Old->getLocation(), diag::note_previous_declaration);
637  }
638  }
639 
640  const FunctionDecl *Def;
641  // C++11 [dcl.constexpr]p1: If any declaration of a function or function
642  // template has a constexpr specifier then all its declarations shall
643  // contain the constexpr specifier.
644  if (New->isConstexpr() != Old->isConstexpr()) {
645  Diag(New->getLocation(), diag::err_constexpr_redecl_mismatch)
646  << New << New->isConstexpr();
647  Diag(Old->getLocation(), diag::note_previous_declaration);
648  Invalid = true;
649  } else if (!Old->getMostRecentDecl()->isInlined() && New->isInlined() &&
650  Old->isDefined(Def) &&
651  // If a friend function is inlined but does not have 'inline'
652  // specifier, it is a definition. Do not report attribute conflict
653  // in this case, redefinition will be diagnosed later.
654  (New->isInlineSpecified() ||
655  New->getFriendObjectKind() == Decl::FOK_None)) {
656  // C++11 [dcl.fcn.spec]p4:
657  // If the definition of a function appears in a translation unit before its
658  // first declaration as inline, the program is ill-formed.
659  Diag(New->getLocation(), diag::err_inline_decl_follows_def) << New;
660  Diag(Def->getLocation(), diag::note_previous_definition);
661  Invalid = true;
662  }
663 
664  // FIXME: It's not clear what should happen if multiple declarations of a
665  // deduction guide have different explicitness. For now at least we simply
666  // reject any case where the explicitness changes.
667  auto *NewGuide = dyn_cast<CXXDeductionGuideDecl>(New);
668  if (NewGuide && NewGuide->isExplicitSpecified() !=
669  cast<CXXDeductionGuideDecl>(Old)->isExplicitSpecified()) {
670  Diag(New->getLocation(), diag::err_deduction_guide_explicit_mismatch)
671  << NewGuide->isExplicitSpecified();
672  Diag(Old->getLocation(), diag::note_previous_declaration);
673  }
674 
675  // C++11 [dcl.fct.default]p4: If a friend declaration specifies a default
676  // argument expression, that declaration shall be a definition and shall be
677  // the only declaration of the function or function template in the
678  // translation unit.
681  Diag(New->getLocation(), diag::err_friend_decl_with_def_arg_redeclared);
682  Diag(Old->getLocation(), diag::note_previous_declaration);
683  Invalid = true;
684  }
685 
686  return Invalid;
687 }
688 
689 NamedDecl *
691  MultiTemplateParamsArg TemplateParamLists) {
692  assert(D.isDecompositionDeclarator());
694 
695  // The syntax only allows a decomposition declarator as a simple-declaration,
696  // a for-range-declaration, or a condition in Clang, but we parse it in more
697  // cases than that.
699  Diag(Decomp.getLSquareLoc(), diag::err_decomp_decl_context)
700  << Decomp.getSourceRange();
701  return nullptr;
702  }
703 
704  if (!TemplateParamLists.empty()) {
705  // FIXME: There's no rule against this, but there are also no rules that
706  // would actually make it usable, so we reject it for now.
707  Diag(TemplateParamLists.front()->getTemplateLoc(),
708  diag::err_decomp_decl_template);
709  return nullptr;
710  }
711 
712  Diag(Decomp.getLSquareLoc(),
713  !getLangOpts().CPlusPlus17
714  ? diag::ext_decomp_decl
716  ? diag::ext_decomp_decl_cond
717  : diag::warn_cxx14_compat_decomp_decl)
718  << Decomp.getSourceRange();
719 
720  // The semantic context is always just the current context.
721  DeclContext *const DC = CurContext;
722 
723  // C++1z [dcl.dcl]/8:
724  // The decl-specifier-seq shall contain only the type-specifier auto
725  // and cv-qualifiers.
726  auto &DS = D.getDeclSpec();
727  {
728  SmallVector<StringRef, 8> BadSpecifiers;
729  SmallVector<SourceLocation, 8> BadSpecifierLocs;
730  if (auto SCS = DS.getStorageClassSpec()) {
731  BadSpecifiers.push_back(DeclSpec::getSpecifierName(SCS));
732  BadSpecifierLocs.push_back(DS.getStorageClassSpecLoc());
733  }
734  if (auto TSCS = DS.getThreadStorageClassSpec()) {
735  BadSpecifiers.push_back(DeclSpec::getSpecifierName(TSCS));
736  BadSpecifierLocs.push_back(DS.getThreadStorageClassSpecLoc());
737  }
738  if (DS.isConstexprSpecified()) {
739  BadSpecifiers.push_back("constexpr");
740  BadSpecifierLocs.push_back(DS.getConstexprSpecLoc());
741  }
742  if (DS.isInlineSpecified()) {
743  BadSpecifiers.push_back("inline");
744  BadSpecifierLocs.push_back(DS.getInlineSpecLoc());
745  }
746  if (!BadSpecifiers.empty()) {
747  auto &&Err = Diag(BadSpecifierLocs.front(), diag::err_decomp_decl_spec);
748  Err << (int)BadSpecifiers.size()
749  << llvm::join(BadSpecifiers.begin(), BadSpecifiers.end(), " ");
750  // Don't add FixItHints to remove the specifiers; we do still respect
751  // them when building the underlying variable.
752  for (auto Loc : BadSpecifierLocs)
753  Err << SourceRange(Loc, Loc);
754  }
755  // We can't recover from it being declared as a typedef.
756  if (DS.getStorageClassSpec() == DeclSpec::SCS_typedef)
757  return nullptr;
758  }
759 
760  TypeSourceInfo *TInfo = GetTypeForDeclarator(D, S);
761  QualType R = TInfo->getType();
762 
763  if (DiagnoseUnexpandedParameterPack(D.getIdentifierLoc(), TInfo,
764  UPPC_DeclarationType))
765  D.setInvalidType();
766 
767  // The syntax only allows a single ref-qualifier prior to the decomposition
768  // declarator. No other declarator chunks are permitted. Also check the type
769  // specifier here.
770  if (DS.getTypeSpecType() != DeclSpec::TST_auto ||
771  D.hasGroupingParens() || D.getNumTypeObjects() > 1 ||
772  (D.getNumTypeObjects() == 1 &&
774  Diag(Decomp.getLSquareLoc(),
775  (D.hasGroupingParens() ||
776  (D.getNumTypeObjects() &&
778  ? diag::err_decomp_decl_parens
779  : diag::err_decomp_decl_type)
780  << R;
781 
782  // In most cases, there's no actual problem with an explicitly-specified
783  // type, but a function type won't work here, and ActOnVariableDeclarator
784  // shouldn't be called for such a type.
785  if (R->isFunctionType())
786  D.setInvalidType();
787  }
788 
789  // Build the BindingDecls.
791 
792  // Build the BindingDecls.
793  for (auto &B : D.getDecompositionDeclarator().bindings()) {
794  // Check for name conflicts.
795  DeclarationNameInfo NameInfo(B.Name, B.NameLoc);
796  LookupResult Previous(*this, NameInfo, LookupOrdinaryName,
797  ForVisibleRedeclaration);
798  LookupName(Previous, S,
799  /*CreateBuiltins*/DC->getRedeclContext()->isTranslationUnit());
800 
801  // It's not permitted to shadow a template parameter name.
802  if (Previous.isSingleResult() &&
803  Previous.getFoundDecl()->isTemplateParameter()) {
804  DiagnoseTemplateParameterShadow(D.getIdentifierLoc(),
805  Previous.getFoundDecl());
806  Previous.clear();
807  }
808 
809  bool ConsiderLinkage = DC->isFunctionOrMethod() &&
810  DS.getStorageClassSpec() == DeclSpec::SCS_extern;
811  FilterLookupForScope(Previous, DC, S, ConsiderLinkage,
812  /*AllowInlineNamespace*/false);
813  if (!Previous.empty()) {
814  auto *Old = Previous.getRepresentativeDecl();
815  Diag(B.NameLoc, diag::err_redefinition) << B.Name;
816  Diag(Old->getLocation(), diag::note_previous_definition);
817  }
818 
819  auto *BD = BindingDecl::Create(Context, DC, B.NameLoc, B.Name);
820  PushOnScopeChains(BD, S, true);
821  Bindings.push_back(BD);
822  ParsingInitForAutoVars.insert(BD);
823  }
824 
825  // There are no prior lookup results for the variable itself, because it
826  // is unnamed.
827  DeclarationNameInfo NameInfo((IdentifierInfo *)nullptr,
828  Decomp.getLSquareLoc());
829  LookupResult Previous(*this, NameInfo, LookupOrdinaryName,
830  ForVisibleRedeclaration);
831 
832  // Build the variable that holds the non-decomposed object.
833  bool AddToScope = true;
834  NamedDecl *New =
835  ActOnVariableDeclarator(S, D, DC, TInfo, Previous,
836  MultiTemplateParamsArg(), AddToScope, Bindings);
837  if (AddToScope) {
838  S->AddDecl(New);
839  CurContext->addHiddenDecl(New);
840  }
841 
842  if (isInOpenMPDeclareTargetContext())
843  checkDeclIsAllowedInOpenMPTarget(nullptr, New);
844 
845  return New;
846 }
847 
849  Sema &S, ArrayRef<BindingDecl *> Bindings, ValueDecl *Src,
850  QualType DecompType, const llvm::APSInt &NumElems, QualType ElemType,
851  llvm::function_ref<ExprResult(SourceLocation, Expr *, unsigned)> GetInit) {
852  if ((int64_t)Bindings.size() != NumElems) {
853  S.Diag(Src->getLocation(), diag::err_decomp_decl_wrong_number_bindings)
854  << DecompType << (unsigned)Bindings.size() << NumElems.toString(10)
855  << (NumElems < Bindings.size());
856  return true;
857  }
858 
859  unsigned I = 0;
860  for (auto *B : Bindings) {
861  SourceLocation Loc = B->getLocation();
862  ExprResult E = S.BuildDeclRefExpr(Src, DecompType, VK_LValue, Loc);
863  if (E.isInvalid())
864  return true;
865  E = GetInit(Loc, E.get(), I++);
866  if (E.isInvalid())
867  return true;
868  B->setBinding(ElemType, E.get());
869  }
870 
871  return false;
872 }
873 
875  ArrayRef<BindingDecl *> Bindings,
876  ValueDecl *Src, QualType DecompType,
877  const llvm::APSInt &NumElems,
878  QualType ElemType) {
880  S, Bindings, Src, DecompType, NumElems, ElemType,
881  [&](SourceLocation Loc, Expr *Base, unsigned I) -> ExprResult {
882  ExprResult E = S.ActOnIntegerConstant(Loc, I);
883  if (E.isInvalid())
884  return ExprError();
885  return S.CreateBuiltinArraySubscriptExpr(Base, Loc, E.get(), Loc);
886  });
887 }
888 
890  ValueDecl *Src, QualType DecompType,
891  const ConstantArrayType *CAT) {
892  return checkArrayLikeDecomposition(S, Bindings, Src, DecompType,
893  llvm::APSInt(CAT->getSize()),
894  CAT->getElementType());
895 }
896 
898  ValueDecl *Src, QualType DecompType,
899  const VectorType *VT) {
901  S, Bindings, Src, DecompType, llvm::APSInt::get(VT->getNumElements()),
903  DecompType.getQualifiers()));
904 }
905 
907  ArrayRef<BindingDecl *> Bindings,
908  ValueDecl *Src, QualType DecompType,
909  const ComplexType *CT) {
911  S, Bindings, Src, DecompType, llvm::APSInt::get(2),
913  DecompType.getQualifiers()),
914  [&](SourceLocation Loc, Expr *Base, unsigned I) -> ExprResult {
915  return S.CreateBuiltinUnaryOp(Loc, I ? UO_Imag : UO_Real, Base);
916  });
917 }
918 
920  TemplateArgumentListInfo &Args) {
921  SmallString<128> SS;
922  llvm::raw_svector_ostream OS(SS);
923  bool First = true;
924  for (auto &Arg : Args.arguments()) {
925  if (!First)
926  OS << ", ";
927  Arg.getArgument().print(PrintingPolicy, OS);
928  First = false;
929  }
930  return OS.str();
931 }
932 
933 static bool lookupStdTypeTraitMember(Sema &S, LookupResult &TraitMemberLookup,
934  SourceLocation Loc, StringRef Trait,
936  unsigned DiagID) {
937  auto DiagnoseMissing = [&] {
938  if (DiagID)
939  S.Diag(Loc, DiagID) << printTemplateArgs(S.Context.getPrintingPolicy(),
940  Args);
941  return true;
942  };
943 
944  // FIXME: Factor out duplication with lookupPromiseType in SemaCoroutine.
945  NamespaceDecl *Std = S.getStdNamespace();
946  if (!Std)
947  return DiagnoseMissing();
948 
949  // Look up the trait itself, within namespace std. We can diagnose various
950  // problems with this lookup even if we've been asked to not diagnose a
951  // missing specialization, because this can only fail if the user has been
952  // declaring their own names in namespace std or we don't support the
953  // standard library implementation in use.
956  if (!S.LookupQualifiedName(Result, Std))
957  return DiagnoseMissing();
958  if (Result.isAmbiguous())
959  return true;
960 
961  ClassTemplateDecl *TraitTD = Result.getAsSingle<ClassTemplateDecl>();
962  if (!TraitTD) {
963  Result.suppressDiagnostics();
964  NamedDecl *Found = *Result.begin();
965  S.Diag(Loc, diag::err_std_type_trait_not_class_template) << Trait;
966  S.Diag(Found->getLocation(), diag::note_declared_at);
967  return true;
968  }
969 
970  // Build the template-id.
971  QualType TraitTy = S.CheckTemplateIdType(TemplateName(TraitTD), Loc, Args);
972  if (TraitTy.isNull())
973  return true;
974  if (!S.isCompleteType(Loc, TraitTy)) {
975  if (DiagID)
977  Loc, TraitTy, DiagID,
979  return true;
980  }
981 
982  CXXRecordDecl *RD = TraitTy->getAsCXXRecordDecl();
983  assert(RD && "specialization of class template is not a class?");
984 
985  // Look up the member of the trait type.
986  S.LookupQualifiedName(TraitMemberLookup, RD);
987  return TraitMemberLookup.isAmbiguous();
988 }
989 
990 static TemplateArgumentLoc
992  uint64_t I) {
993  TemplateArgument Arg(S.Context, S.Context.MakeIntValue(I, T), T);
994  return S.getTrivialTemplateArgumentLoc(Arg, T, Loc);
995 }
996 
997 static TemplateArgumentLoc
1000 }
1001 
1002 namespace { enum class IsTupleLike { TupleLike, NotTupleLike, Error }; }
1003 
1005  llvm::APSInt &Size) {
1008 
1010  LookupResult R(S, Value, Loc, Sema::LookupOrdinaryName);
1011 
1012  // Form template argument list for tuple_size<T>.
1013  TemplateArgumentListInfo Args(Loc, Loc);
1015 
1016  // If there's no tuple_size specialization, it's not tuple-like.
1017  if (lookupStdTypeTraitMember(S, R, Loc, "tuple_size", Args, /*DiagID*/0))
1018  return IsTupleLike::NotTupleLike;
1019 
1020  // If we get this far, we've committed to the tuple interpretation, but
1021  // we can still fail if there actually isn't a usable ::value.
1022 
1023  struct ICEDiagnoser : Sema::VerifyICEDiagnoser {
1024  LookupResult &R;
1026  ICEDiagnoser(LookupResult &R, TemplateArgumentListInfo &Args)
1027  : R(R), Args(Args) {}
1028  void diagnoseNotICE(Sema &S, SourceLocation Loc, SourceRange SR) {
1029  S.Diag(Loc, diag::err_decomp_decl_std_tuple_size_not_constant)
1031  }
1032  } Diagnoser(R, Args);
1033 
1034  if (R.empty()) {
1035  Diagnoser.diagnoseNotICE(S, Loc, SourceRange());
1036  return IsTupleLike::Error;
1037  }
1038 
1039  ExprResult E =
1040  S.BuildDeclarationNameExpr(CXXScopeSpec(), R, /*NeedsADL*/false);
1041  if (E.isInvalid())
1042  return IsTupleLike::Error;
1043 
1044  E = S.VerifyIntegerConstantExpression(E.get(), &Size, Diagnoser, false);
1045  if (E.isInvalid())
1046  return IsTupleLike::Error;
1047 
1048  return IsTupleLike::TupleLike;
1049 }
1050 
1051 /// \return std::tuple_element<I, T>::type.
1053  unsigned I, QualType T) {
1054  // Form template argument list for tuple_element<I, T>.
1055  TemplateArgumentListInfo Args(Loc, Loc);
1056  Args.addArgument(
1059 
1060  DeclarationName TypeDN = S.PP.getIdentifierInfo("type");
1061  LookupResult R(S, TypeDN, Loc, Sema::LookupOrdinaryName);
1063  S, R, Loc, "tuple_element", Args,
1064  diag::err_decomp_decl_std_tuple_element_not_specialized))
1065  return QualType();
1066 
1067  auto *TD = R.getAsSingle<TypeDecl>();
1068  if (!TD) {
1069  R.suppressDiagnostics();
1070  S.Diag(Loc, diag::err_decomp_decl_std_tuple_element_not_specialized)
1072  if (!R.empty())
1073  S.Diag(R.getRepresentativeDecl()->getLocation(), diag::note_declared_at);
1074  return QualType();
1075  }
1076 
1077  return S.Context.getTypeDeclType(TD);
1078 }
1079 
1080 namespace {
1081 struct BindingDiagnosticTrap {
1082  Sema &S;
1083  DiagnosticErrorTrap Trap;
1084  BindingDecl *BD;
1085 
1086  BindingDiagnosticTrap(Sema &S, BindingDecl *BD)
1087  : S(S), Trap(S.Diags), BD(BD) {}
1088  ~BindingDiagnosticTrap() {
1089  if (Trap.hasErrorOccurred())
1090  S.Diag(BD->getLocation(), diag::note_in_binding_decl_init) << BD;
1091  }
1092 };
1093 }
1094 
1096  ArrayRef<BindingDecl *> Bindings,
1097  VarDecl *Src, QualType DecompType,
1098  const llvm::APSInt &TupleSize) {
1099  if ((int64_t)Bindings.size() != TupleSize) {
1100  S.Diag(Src->getLocation(), diag::err_decomp_decl_wrong_number_bindings)
1101  << DecompType << (unsigned)Bindings.size() << TupleSize.toString(10)
1102  << (TupleSize < Bindings.size());
1103  return true;
1104  }
1105 
1106  if (Bindings.empty())
1107  return false;
1108 
1109  DeclarationName GetDN = S.PP.getIdentifierInfo("get");
1110 
1111  // [dcl.decomp]p3:
1112  // The unqualified-id get is looked up in the scope of E by class member
1113  // access lookup
1114  LookupResult MemberGet(S, GetDN, Src->getLocation(), Sema::LookupMemberName);
1115  bool UseMemberGet = false;
1116  if (S.isCompleteType(Src->getLocation(), DecompType)) {
1117  if (auto *RD = DecompType->getAsCXXRecordDecl())
1118  S.LookupQualifiedName(MemberGet, RD);
1119  if (MemberGet.isAmbiguous())
1120  return true;
1121  UseMemberGet = !MemberGet.empty();
1122  S.FilterAcceptableTemplateNames(MemberGet);
1123  }
1124 
1125  unsigned I = 0;
1126  for (auto *B : Bindings) {
1127  BindingDiagnosticTrap Trap(S, B);
1128  SourceLocation Loc = B->getLocation();
1129 
1130  ExprResult E = S.BuildDeclRefExpr(Src, DecompType, VK_LValue, Loc);
1131  if (E.isInvalid())
1132  return true;
1133 
1134  // e is an lvalue if the type of the entity is an lvalue reference and
1135  // an xvalue otherwise
1136  if (!Src->getType()->isLValueReferenceType())
1137  E = ImplicitCastExpr::Create(S.Context, E.get()->getType(), CK_NoOp,
1138  E.get(), nullptr, VK_XValue);
1139 
1140  TemplateArgumentListInfo Args(Loc, Loc);
1141  Args.addArgument(
1143 
1144  if (UseMemberGet) {
1145  // if [lookup of member get] finds at least one declaration, the
1146  // initializer is e.get<i-1>().
1147  E = S.BuildMemberReferenceExpr(E.get(), DecompType, Loc, false,
1148  CXXScopeSpec(), SourceLocation(), nullptr,
1149  MemberGet, &Args, nullptr);
1150  if (E.isInvalid())
1151  return true;
1152 
1153  E = S.ActOnCallExpr(nullptr, E.get(), Loc, None, Loc);
1154  } else {
1155  // Otherwise, the initializer is get<i-1>(e), where get is looked up
1156  // in the associated namespaces.
1159  DeclarationNameInfo(GetDN, Loc), /*RequiresADL*/true, &Args,
1161 
1162  Expr *Arg = E.get();
1163  E = S.ActOnCallExpr(nullptr, Get, Loc, Arg, Loc);
1164  }
1165  if (E.isInvalid())
1166  return true;
1167  Expr *Init = E.get();
1168 
1169  // Given the type T designated by std::tuple_element<i - 1, E>::type,
1170  QualType T = getTupleLikeElementType(S, Loc, I, DecompType);
1171  if (T.isNull())
1172  return true;
1173 
1174  // each vi is a variable of type "reference to T" initialized with the
1175  // initializer, where the reference is an lvalue reference if the
1176  // initializer is an lvalue and an rvalue reference otherwise
1177  QualType RefType =
1178  S.BuildReferenceType(T, E.get()->isLValue(), Loc, B->getDeclName());
1179  if (RefType.isNull())
1180  return true;
1181  auto *RefVD = VarDecl::Create(
1182  S.Context, Src->getDeclContext(), Loc, Loc,
1183  B->getDeclName().getAsIdentifierInfo(), RefType,
1186  RefVD->setTSCSpec(Src->getTSCSpec());
1187  RefVD->setImplicit();
1188  if (Src->isInlineSpecified())
1189  RefVD->setInlineSpecified();
1190  RefVD->getLexicalDeclContext()->addHiddenDecl(RefVD);
1191 
1194  InitializationSequence Seq(S, Entity, Kind, Init);
1195  E = Seq.Perform(S, Entity, Kind, Init);
1196  if (E.isInvalid())
1197  return true;
1198  E = S.ActOnFinishFullExpr(E.get(), Loc);
1199  if (E.isInvalid())
1200  return true;
1201  RefVD->setInit(E.get());
1202  RefVD->checkInitIsICE();
1203 
1205  DeclarationNameInfo(B->getDeclName(), Loc),
1206  RefVD);
1207  if (E.isInvalid())
1208  return true;
1209 
1210  B->setBinding(T, E.get());
1211  I++;
1212  }
1213 
1214  return false;
1215 }
1216 
1217 /// Find the base class to decompose in a built-in decomposition of a class type.
1218 /// This base class search is, unfortunately, not quite like any other that we
1219 /// perform anywhere else in C++.
1221  SourceLocation Loc,
1222  const CXXRecordDecl *RD,
1223  CXXCastPath &BasePath) {
1224  auto BaseHasFields = [](const CXXBaseSpecifier *Specifier,
1225  CXXBasePath &Path) {
1226  return Specifier->getType()->getAsCXXRecordDecl()->hasDirectFields();
1227  };
1228 
1229  const CXXRecordDecl *ClassWithFields = nullptr;
1230  if (RD->hasDirectFields())
1231  // [dcl.decomp]p4:
1232  // Otherwise, all of E's non-static data members shall be public direct
1233  // members of E ...
1234  ClassWithFields = RD;
1235  else {
1236  // ... or of ...
1237  CXXBasePaths Paths;
1238  Paths.setOrigin(const_cast<CXXRecordDecl*>(RD));
1239  if (!RD->lookupInBases(BaseHasFields, Paths)) {
1240  // If no classes have fields, just decompose RD itself. (This will work
1241  // if and only if zero bindings were provided.)
1242  return RD;
1243  }
1244 
1245  CXXBasePath *BestPath = nullptr;
1246  for (auto &P : Paths) {
1247  if (!BestPath)
1248  BestPath = &P;
1249  else if (!S.Context.hasSameType(P.back().Base->getType(),
1250  BestPath->back().Base->getType())) {
1251  // ... the same ...
1252  S.Diag(Loc, diag::err_decomp_decl_multiple_bases_with_members)
1253  << false << RD << BestPath->back().Base->getType()
1254  << P.back().Base->getType();
1255  return nullptr;
1256  } else if (P.Access < BestPath->Access) {
1257  BestPath = &P;
1258  }
1259  }
1260 
1261  // ... unambiguous ...
1262  QualType BaseType = BestPath->back().Base->getType();
1263  if (Paths.isAmbiguous(S.Context.getCanonicalType(BaseType))) {
1264  S.Diag(Loc, diag::err_decomp_decl_ambiguous_base)
1265  << RD << BaseType << S.getAmbiguousPathsDisplayString(Paths);
1266  return nullptr;
1267  }
1268 
1269  // ... public base class of E.
1270  if (BestPath->Access != AS_public) {
1271  S.Diag(Loc, diag::err_decomp_decl_non_public_base)
1272  << RD << BaseType;
1273  for (auto &BS : *BestPath) {
1274  if (BS.Base->getAccessSpecifier() != AS_public) {
1275  S.Diag(BS.Base->getLocStart(), diag::note_access_constrained_by_path)
1276  << (BS.Base->getAccessSpecifier() == AS_protected)
1277  << (BS.Base->getAccessSpecifierAsWritten() == AS_none);
1278  break;
1279  }
1280  }
1281  return nullptr;
1282  }
1283 
1284  ClassWithFields = BaseType->getAsCXXRecordDecl();
1285  S.BuildBasePathArray(Paths, BasePath);
1286  }
1287 
1288  // The above search did not check whether the selected class itself has base
1289  // classes with fields, so check that now.
1290  CXXBasePaths Paths;
1291  if (ClassWithFields->lookupInBases(BaseHasFields, Paths)) {
1292  S.Diag(Loc, diag::err_decomp_decl_multiple_bases_with_members)
1293  << (ClassWithFields == RD) << RD << ClassWithFields
1294  << Paths.front().back().Base->getType();
1295  return nullptr;
1296  }
1297 
1298  return ClassWithFields;
1299 }
1300 
1302  ValueDecl *Src, QualType DecompType,
1303  const CXXRecordDecl *RD) {
1304  CXXCastPath BasePath;
1305  RD = findDecomposableBaseClass(S, Src->getLocation(), RD, BasePath);
1306  if (!RD)
1307  return true;
1309  DecompType.getQualifiers());
1310 
1311  auto DiagnoseBadNumberOfBindings = [&]() -> bool {
1312  unsigned NumFields =
1313  std::count_if(RD->field_begin(), RD->field_end(),
1314  [](FieldDecl *FD) { return !FD->isUnnamedBitfield(); });
1315  assert(Bindings.size() != NumFields);
1316  S.Diag(Src->getLocation(), diag::err_decomp_decl_wrong_number_bindings)
1317  << DecompType << (unsigned)Bindings.size() << NumFields
1318  << (NumFields < Bindings.size());
1319  return true;
1320  };
1321 
1322  // all of E's non-static data members shall be public [...] members,
1323  // E shall not have an anonymous union member, ...
1324  unsigned I = 0;
1325  for (auto *FD : RD->fields()) {
1326  if (FD->isUnnamedBitfield())
1327  continue;
1328 
1329  if (FD->isAnonymousStructOrUnion()) {
1330  S.Diag(Src->getLocation(), diag::err_decomp_decl_anon_union_member)
1331  << DecompType << FD->getType()->isUnionType();
1332  S.Diag(FD->getLocation(), diag::note_declared_at);
1333  return true;
1334  }
1335 
1336  // We have a real field to bind.
1337  if (I >= Bindings.size())
1338  return DiagnoseBadNumberOfBindings();
1339  auto *B = Bindings[I++];
1340 
1341  SourceLocation Loc = B->getLocation();
1342  if (FD->getAccess() != AS_public) {
1343  S.Diag(Loc, diag::err_decomp_decl_non_public_member) << FD << DecompType;
1344 
1345  // Determine whether the access specifier was explicit.
1346  bool Implicit = true;
1347  for (const auto *D : RD->decls()) {
1348  if (declaresSameEntity(D, FD))
1349  break;
1350  if (isa<AccessSpecDecl>(D)) {
1351  Implicit = false;
1352  break;
1353  }
1354  }
1355 
1356  S.Diag(FD->getLocation(), diag::note_access_natural)
1357  << (FD->getAccess() == AS_protected) << Implicit;
1358  return true;
1359  }
1360 
1361  // Initialize the binding to Src.FD.
1362  ExprResult E = S.BuildDeclRefExpr(Src, DecompType, VK_LValue, Loc);
1363  if (E.isInvalid())
1364  return true;
1365  E = S.ImpCastExprToType(E.get(), BaseType, CK_UncheckedDerivedToBase,
1366  VK_LValue, &BasePath);
1367  if (E.isInvalid())
1368  return true;
1369  E = S.BuildFieldReferenceExpr(E.get(), /*IsArrow*/ false, Loc,
1370  CXXScopeSpec(), FD,
1371  DeclAccessPair::make(FD, FD->getAccess()),
1372  DeclarationNameInfo(FD->getDeclName(), Loc));
1373  if (E.isInvalid())
1374  return true;
1375 
1376  // If the type of the member is T, the referenced type is cv T, where cv is
1377  // the cv-qualification of the decomposition expression.
1378  //
1379  // FIXME: We resolve a defect here: if the field is mutable, we do not add
1380  // 'const' to the type of the field.
1381  Qualifiers Q = DecompType.getQualifiers();
1382  if (FD->isMutable())
1383  Q.removeConst();
1384  B->setBinding(S.BuildQualifiedType(FD->getType(), Loc, Q), E.get());
1385  }
1386 
1387  if (I != Bindings.size())
1388  return DiagnoseBadNumberOfBindings();
1389 
1390  return false;
1391 }
1392 
1394  QualType DecompType = DD->getType();
1395 
1396  // If the type of the decomposition is dependent, then so is the type of
1397  // each binding.
1398  if (DecompType->isDependentType()) {
1399  for (auto *B : DD->bindings())
1400  B->setType(Context.DependentTy);
1401  return;
1402  }
1403 
1404  DecompType = DecompType.getNonReferenceType();
1405  ArrayRef<BindingDecl*> Bindings = DD->bindings();
1406 
1407  // C++1z [dcl.decomp]/2:
1408  // If E is an array type [...]
1409  // As an extension, we also support decomposition of built-in complex and
1410  // vector types.
1411  if (auto *CAT = Context.getAsConstantArrayType(DecompType)) {
1412  if (checkArrayDecomposition(*this, Bindings, DD, DecompType, CAT))
1413  DD->setInvalidDecl();
1414  return;
1415  }
1416  if (auto *VT = DecompType->getAs<VectorType>()) {
1417  if (checkVectorDecomposition(*this, Bindings, DD, DecompType, VT))
1418  DD->setInvalidDecl();
1419  return;
1420  }
1421  if (auto *CT = DecompType->getAs<ComplexType>()) {
1422  if (checkComplexDecomposition(*this, Bindings, DD, DecompType, CT))
1423  DD->setInvalidDecl();
1424  return;
1425  }
1426 
1427  // C++1z [dcl.decomp]/3:
1428  // if the expression std::tuple_size<E>::value is a well-formed integral
1429  // constant expression, [...]
1430  llvm::APSInt TupleSize(32);
1431  switch (isTupleLike(*this, DD->getLocation(), DecompType, TupleSize)) {
1432  case IsTupleLike::Error:
1433  DD->setInvalidDecl();
1434  return;
1435 
1436  case IsTupleLike::TupleLike:
1437  if (checkTupleLikeDecomposition(*this, Bindings, DD, DecompType, TupleSize))
1438  DD->setInvalidDecl();
1439  return;
1440 
1441  case IsTupleLike::NotTupleLike:
1442  break;
1443  }
1444 
1445  // C++1z [dcl.dcl]/8:
1446  // [E shall be of array or non-union class type]
1447  CXXRecordDecl *RD = DecompType->getAsCXXRecordDecl();
1448  if (!RD || RD->isUnion()) {
1449  Diag(DD->getLocation(), diag::err_decomp_decl_unbindable_type)
1450  << DD << !RD << DecompType;
1451  DD->setInvalidDecl();
1452  return;
1453  }
1454 
1455  // C++1z [dcl.decomp]/4:
1456  // all of E's non-static data members shall be [...] direct members of
1457  // E or of the same unambiguous public base class of E, ...
1458  if (checkMemberDecomposition(*this, Bindings, DD, DecompType, RD))
1459  DD->setInvalidDecl();
1460 }
1461 
1462 /// \brief Merge the exception specifications of two variable declarations.
1463 ///
1464 /// This is called when there's a redeclaration of a VarDecl. The function
1465 /// checks if the redeclaration might have an exception specification and
1466 /// validates compatibility and merges the specs if necessary.
1468  // Shortcut if exceptions are disabled.
1469  if (!getLangOpts().CXXExceptions)
1470  return;
1471 
1472  assert(Context.hasSameType(New->getType(), Old->getType()) &&
1473  "Should only be called if types are otherwise the same.");
1474 
1475  QualType NewType = New->getType();
1476  QualType OldType = Old->getType();
1477 
1478  // We're only interested in pointers and references to functions, as well
1479  // as pointers to member functions.
1480  if (const ReferenceType *R = NewType->getAs<ReferenceType>()) {
1481  NewType = R->getPointeeType();
1482  OldType = OldType->getAs<ReferenceType>()->getPointeeType();
1483  } else if (const PointerType *P = NewType->getAs<PointerType>()) {
1484  NewType = P->getPointeeType();
1485  OldType = OldType->getAs<PointerType>()->getPointeeType();
1486  } else if (const MemberPointerType *M = NewType->getAs<MemberPointerType>()) {
1487  NewType = M->getPointeeType();
1488  OldType = OldType->getAs<MemberPointerType>()->getPointeeType();
1489  }
1490 
1491  if (!NewType->isFunctionProtoType())
1492  return;
1493 
1494  // There's lots of special cases for functions. For function pointers, system
1495  // libraries are hopefully not as broken so that we don't need these
1496  // workarounds.
1497  if (CheckEquivalentExceptionSpec(
1498  OldType->getAs<FunctionProtoType>(), Old->getLocation(),
1499  NewType->getAs<FunctionProtoType>(), New->getLocation())) {
1500  New->setInvalidDecl();
1501  }
1502 }
1503 
1504 /// CheckCXXDefaultArguments - Verify that the default arguments for a
1505 /// function declaration are well-formed according to C++
1506 /// [dcl.fct.default].
1508  unsigned NumParams = FD->getNumParams();
1509  unsigned p;
1510 
1511  // Find first parameter with a default argument
1512  for (p = 0; p < NumParams; ++p) {
1513  ParmVarDecl *Param = FD->getParamDecl(p);
1514  if (Param->hasDefaultArg())
1515  break;
1516  }
1517 
1518  // C++11 [dcl.fct.default]p4:
1519  // In a given function declaration, each parameter subsequent to a parameter
1520  // with a default argument shall have a default argument supplied in this or
1521  // a previous declaration or shall be a function parameter pack. A default
1522  // argument shall not be redefined by a later declaration (not even to the
1523  // same value).
1524  unsigned LastMissingDefaultArg = 0;
1525  for (; p < NumParams; ++p) {
1526  ParmVarDecl *Param = FD->getParamDecl(p);
1527  if (!Param->hasDefaultArg() && !Param->isParameterPack()) {
1528  if (Param->isInvalidDecl())
1529  /* We already complained about this parameter. */;
1530  else if (Param->getIdentifier())
1531  Diag(Param->getLocation(),
1532  diag::err_param_default_argument_missing_name)
1533  << Param->getIdentifier();
1534  else
1535  Diag(Param->getLocation(),
1536  diag::err_param_default_argument_missing);
1537 
1538  LastMissingDefaultArg = p;
1539  }
1540  }
1541 
1542  if (LastMissingDefaultArg > 0) {
1543  // Some default arguments were missing. Clear out all of the
1544  // default arguments up to (and including) the last missing
1545  // default argument, so that we leave the function parameters
1546  // in a semantically valid state.
1547  for (p = 0; p <= LastMissingDefaultArg; ++p) {
1548  ParmVarDecl *Param = FD->getParamDecl(p);
1549  if (Param->hasDefaultArg()) {
1550  Param->setDefaultArg(nullptr);
1551  }
1552  }
1553  }
1554 }
1555 
1556 // CheckConstexprParameterTypes - Check whether a function's parameter types
1557 // are all literal types. If so, return true. If not, produce a suitable
1558 // diagnostic and return false.
1559 static bool CheckConstexprParameterTypes(Sema &SemaRef,
1560  const FunctionDecl *FD) {
1561  unsigned ArgIndex = 0;
1562  const FunctionProtoType *FT = FD->getType()->getAs<FunctionProtoType>();
1564  e = FT->param_type_end();
1565  i != e; ++i, ++ArgIndex) {
1566  const ParmVarDecl *PD = FD->getParamDecl(ArgIndex);
1567  SourceLocation ParamLoc = PD->getLocation();
1568  if (!(*i)->isDependentType() &&
1569  SemaRef.RequireLiteralType(ParamLoc, *i,
1570  diag::err_constexpr_non_literal_param,
1571  ArgIndex+1, PD->getSourceRange(),
1572  isa<CXXConstructorDecl>(FD)))
1573  return false;
1574  }
1575  return true;
1576 }
1577 
1578 /// \brief Get diagnostic %select index for tag kind for
1579 /// record diagnostic message.
1580 /// WARNING: Indexes apply to particular diagnostics only!
1581 ///
1582 /// \returns diagnostic %select index.
1584  switch (Tag) {
1585  case TTK_Struct: return 0;
1586  case TTK_Interface: return 1;
1587  case TTK_Class: return 2;
1588  default: llvm_unreachable("Invalid tag kind for record diagnostic!");
1589  }
1590 }
1591 
1592 // CheckConstexprFunctionDecl - Check whether a function declaration satisfies
1593 // the requirements of a constexpr function definition or a constexpr
1594 // constructor definition. If so, return true. If not, produce appropriate
1595 // diagnostics and return false.
1596 //
1597 // This implements C++11 [dcl.constexpr]p3,4, as amended by DR1360.
1599  const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(NewFD);
1600  if (MD && MD->isInstance()) {
1601  // C++11 [dcl.constexpr]p4:
1602  // The definition of a constexpr constructor shall satisfy the following
1603  // constraints:
1604  // - the class shall not have any virtual base classes;
1605  const CXXRecordDecl *RD = MD->getParent();
1606  if (RD->getNumVBases()) {
1607  Diag(NewFD->getLocation(), diag::err_constexpr_virtual_base)
1608  << isa<CXXConstructorDecl>(NewFD)
1610  for (const auto &I : RD->vbases())
1611  Diag(I.getLocStart(),
1612  diag::note_constexpr_virtual_base_here) << I.getSourceRange();
1613  return false;
1614  }
1615  }
1616 
1617  if (!isa<CXXConstructorDecl>(NewFD)) {
1618  // C++11 [dcl.constexpr]p3:
1619  // The definition of a constexpr function shall satisfy the following
1620  // constraints:
1621  // - it shall not be virtual;
1622  const CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(NewFD);
1623  if (Method && Method->isVirtual()) {
1624  Method = Method->getCanonicalDecl();
1625  Diag(Method->getLocation(), diag::err_constexpr_virtual);
1626 
1627  // If it's not obvious why this function is virtual, find an overridden
1628  // function which uses the 'virtual' keyword.
1629  const CXXMethodDecl *WrittenVirtual = Method;
1630  while (!WrittenVirtual->isVirtualAsWritten())
1631  WrittenVirtual = *WrittenVirtual->begin_overridden_methods();
1632  if (WrittenVirtual != Method)
1633  Diag(WrittenVirtual->getLocation(),
1634  diag::note_overridden_virtual_function);
1635  return false;
1636  }
1637 
1638  // - its return type shall be a literal type;
1639  QualType RT = NewFD->getReturnType();
1640  if (!RT->isDependentType() &&
1641  RequireLiteralType(NewFD->getLocation(), RT,
1642  diag::err_constexpr_non_literal_return))
1643  return false;
1644  }
1645 
1646  // - each of its parameter types shall be a literal type;
1647  if (!CheckConstexprParameterTypes(*this, NewFD))
1648  return false;
1649 
1650  return true;
1651 }
1652 
1653 /// Check the given declaration statement is legal within a constexpr function
1654 /// body. C++11 [dcl.constexpr]p3,p4, and C++1y [dcl.constexpr]p3.
1655 ///
1656 /// \return true if the body is OK (maybe only as an extension), false if we
1657 /// have diagnosed a problem.
1658 static bool CheckConstexprDeclStmt(Sema &SemaRef, const FunctionDecl *Dcl,
1659  DeclStmt *DS, SourceLocation &Cxx1yLoc) {
1660  // C++11 [dcl.constexpr]p3 and p4:
1661  // The definition of a constexpr function(p3) or constructor(p4) [...] shall
1662  // contain only
1663  for (const auto *DclIt : DS->decls()) {
1664  switch (DclIt->getKind()) {
1665  case Decl::StaticAssert:
1666  case Decl::Using:
1667  case Decl::UsingShadow:
1668  case Decl::UsingDirective:
1669  case Decl::UnresolvedUsingTypename:
1670  case Decl::UnresolvedUsingValue:
1671  // - static_assert-declarations
1672  // - using-declarations,
1673  // - using-directives,
1674  continue;
1675 
1676  case Decl::Typedef:
1677  case Decl::TypeAlias: {
1678  // - typedef declarations and alias-declarations that do not define
1679  // classes or enumerations,
1680  const auto *TN = cast<TypedefNameDecl>(DclIt);
1681  if (TN->getUnderlyingType()->isVariablyModifiedType()) {
1682  // Don't allow variably-modified types in constexpr functions.
1683  TypeLoc TL = TN->getTypeSourceInfo()->getTypeLoc();
1684  SemaRef.Diag(TL.getBeginLoc(), diag::err_constexpr_vla)
1685  << TL.getSourceRange() << TL.getType()
1686  << isa<CXXConstructorDecl>(Dcl);
1687  return false;
1688  }
1689  continue;
1690  }
1691 
1692  case Decl::Enum:
1693  case Decl::CXXRecord:
1694  // C++1y allows types to be defined, not just declared.
1695  if (cast<TagDecl>(DclIt)->isThisDeclarationADefinition())
1696  SemaRef.Diag(DS->getLocStart(),
1697  SemaRef.getLangOpts().CPlusPlus14
1698  ? diag::warn_cxx11_compat_constexpr_type_definition
1699  : diag::ext_constexpr_type_definition)
1700  << isa<CXXConstructorDecl>(Dcl);
1701  continue;
1702 
1703  case Decl::EnumConstant:
1704  case Decl::IndirectField:
1705  case Decl::ParmVar:
1706  // These can only appear with other declarations which are banned in
1707  // C++11 and permitted in C++1y, so ignore them.
1708  continue;
1709 
1710  case Decl::Var:
1711  case Decl::Decomposition: {
1712  // C++1y [dcl.constexpr]p3 allows anything except:
1713  // a definition of a variable of non-literal type or of static or
1714  // thread storage duration or for which no initialization is performed.
1715  const auto *VD = cast<VarDecl>(DclIt);
1716  if (VD->isThisDeclarationADefinition()) {
1717  if (VD->isStaticLocal()) {
1718  SemaRef.Diag(VD->getLocation(),
1719  diag::err_constexpr_local_var_static)
1720  << isa<CXXConstructorDecl>(Dcl)
1721  << (VD->getTLSKind() == VarDecl::TLS_Dynamic);
1722  return false;
1723  }
1724  if (!VD->getType()->isDependentType() &&
1725  SemaRef.RequireLiteralType(
1726  VD->getLocation(), VD->getType(),
1727  diag::err_constexpr_local_var_non_literal_type,
1728  isa<CXXConstructorDecl>(Dcl)))
1729  return false;
1730  if (!VD->getType()->isDependentType() &&
1731  !VD->hasInit() && !VD->isCXXForRangeDecl()) {
1732  SemaRef.Diag(VD->getLocation(),
1733  diag::err_constexpr_local_var_no_init)
1734  << isa<CXXConstructorDecl>(Dcl);
1735  return false;
1736  }
1737  }
1738  SemaRef.Diag(VD->getLocation(),
1739  SemaRef.getLangOpts().CPlusPlus14
1740  ? diag::warn_cxx11_compat_constexpr_local_var
1741  : diag::ext_constexpr_local_var)
1742  << isa<CXXConstructorDecl>(Dcl);
1743  continue;
1744  }
1745 
1746  case Decl::NamespaceAlias:
1747  case Decl::Function:
1748  // These are disallowed in C++11 and permitted in C++1y. Allow them
1749  // everywhere as an extension.
1750  if (!Cxx1yLoc.isValid())
1751  Cxx1yLoc = DS->getLocStart();
1752  continue;
1753 
1754  default:
1755  SemaRef.Diag(DS->getLocStart(), diag::err_constexpr_body_invalid_stmt)
1756  << isa<CXXConstructorDecl>(Dcl);
1757  return false;
1758  }
1759  }
1760 
1761  return true;
1762 }
1763 
1764 /// Check that the given field is initialized within a constexpr constructor.
1765 ///
1766 /// \param Dcl The constexpr constructor being checked.
1767 /// \param Field The field being checked. This may be a member of an anonymous
1768 /// struct or union nested within the class being checked.
1769 /// \param Inits All declarations, including anonymous struct/union members and
1770 /// indirect members, for which any initialization was provided.
1771 /// \param Diagnosed Set to true if an error is produced.
1773  const FunctionDecl *Dcl,
1774  FieldDecl *Field,
1775  llvm::SmallSet<Decl*, 16> &Inits,
1776  bool &Diagnosed) {
1777  if (Field->isInvalidDecl())
1778  return;
1779 
1780  if (Field->isUnnamedBitfield())
1781  return;
1782 
1783  // Anonymous unions with no variant members and empty anonymous structs do not
1784  // need to be explicitly initialized. FIXME: Anonymous structs that contain no
1785  // indirect fields don't need initializing.
1786  if (Field->isAnonymousStructOrUnion() &&
1787  (Field->getType()->isUnionType()
1788  ? !Field->getType()->getAsCXXRecordDecl()->hasVariantMembers()
1789  : Field->getType()->getAsCXXRecordDecl()->isEmpty()))
1790  return;
1791 
1792  if (!Inits.count(Field)) {
1793  if (!Diagnosed) {
1794  SemaRef.Diag(Dcl->getLocation(), diag::err_constexpr_ctor_missing_init);
1795  Diagnosed = true;
1796  }
1797  SemaRef.Diag(Field->getLocation(), diag::note_constexpr_ctor_missing_init);
1798  } else if (Field->isAnonymousStructOrUnion()) {
1799  const RecordDecl *RD = Field->getType()->castAs<RecordType>()->getDecl();
1800  for (auto *I : RD->fields())
1801  // If an anonymous union contains an anonymous struct of which any member
1802  // is initialized, all members must be initialized.
1803  if (!RD->isUnion() || Inits.count(I))
1804  CheckConstexprCtorInitializer(SemaRef, Dcl, I, Inits, Diagnosed);
1805  }
1806 }
1807 
1808 /// Check the provided statement is allowed in a constexpr function
1809 /// definition.
1810 static bool
1812  SmallVectorImpl<SourceLocation> &ReturnStmts,
1813  SourceLocation &Cxx1yLoc) {
1814  // - its function-body shall be [...] a compound-statement that contains only
1815  switch (S->getStmtClass()) {
1816  case Stmt::NullStmtClass:
1817  // - null statements,
1818  return true;
1819 
1820  case Stmt::DeclStmtClass:
1821  // - static_assert-declarations
1822  // - using-declarations,
1823  // - using-directives,
1824  // - typedef declarations and alias-declarations that do not define
1825  // classes or enumerations,
1826  if (!CheckConstexprDeclStmt(SemaRef, Dcl, cast<DeclStmt>(S), Cxx1yLoc))
1827  return false;
1828  return true;
1829 
1830  case Stmt::ReturnStmtClass:
1831  // - and exactly one return statement;
1832  if (isa<CXXConstructorDecl>(Dcl)) {
1833  // C++1y allows return statements in constexpr constructors.
1834  if (!Cxx1yLoc.isValid())
1835  Cxx1yLoc = S->getLocStart();
1836  return true;
1837  }
1838 
1839  ReturnStmts.push_back(S->getLocStart());
1840  return true;
1841 
1842  case Stmt::CompoundStmtClass: {
1843  // C++1y allows compound-statements.
1844  if (!Cxx1yLoc.isValid())
1845  Cxx1yLoc = S->getLocStart();
1846 
1847  CompoundStmt *CompStmt = cast<CompoundStmt>(S);
1848  for (auto *BodyIt : CompStmt->body()) {
1849  if (!CheckConstexprFunctionStmt(SemaRef, Dcl, BodyIt, ReturnStmts,
1850  Cxx1yLoc))
1851  return false;
1852  }
1853  return true;
1854  }
1855 
1856  case Stmt::AttributedStmtClass:
1857  if (!Cxx1yLoc.isValid())
1858  Cxx1yLoc = S->getLocStart();
1859  return true;
1860 
1861  case Stmt::IfStmtClass: {
1862  // C++1y allows if-statements.
1863  if (!Cxx1yLoc.isValid())
1864  Cxx1yLoc = S->getLocStart();
1865 
1866  IfStmt *If = cast<IfStmt>(S);
1867  if (!CheckConstexprFunctionStmt(SemaRef, Dcl, If->getThen(), ReturnStmts,
1868  Cxx1yLoc))
1869  return false;
1870  if (If->getElse() &&
1871  !CheckConstexprFunctionStmt(SemaRef, Dcl, If->getElse(), ReturnStmts,
1872  Cxx1yLoc))
1873  return false;
1874  return true;
1875  }
1876 
1877  case Stmt::WhileStmtClass:
1878  case Stmt::DoStmtClass:
1879  case Stmt::ForStmtClass:
1880  case Stmt::CXXForRangeStmtClass:
1881  case Stmt::ContinueStmtClass:
1882  // C++1y allows all of these. We don't allow them as extensions in C++11,
1883  // because they don't make sense without variable mutation.
1884  if (!SemaRef.getLangOpts().CPlusPlus14)
1885  break;
1886  if (!Cxx1yLoc.isValid())
1887  Cxx1yLoc = S->getLocStart();
1888  for (Stmt *SubStmt : S->children())
1889  if (SubStmt &&
1890  !CheckConstexprFunctionStmt(SemaRef, Dcl, SubStmt, ReturnStmts,
1891  Cxx1yLoc))
1892  return false;
1893  return true;
1894 
1895  case Stmt::SwitchStmtClass:
1896  case Stmt::CaseStmtClass:
1897  case Stmt::DefaultStmtClass:
1898  case Stmt::BreakStmtClass:
1899  // C++1y allows switch-statements, and since they don't need variable
1900  // mutation, we can reasonably allow them in C++11 as an extension.
1901  if (!Cxx1yLoc.isValid())
1902  Cxx1yLoc = S->getLocStart();
1903  for (Stmt *SubStmt : S->children())
1904  if (SubStmt &&
1905  !CheckConstexprFunctionStmt(SemaRef, Dcl, SubStmt, ReturnStmts,
1906  Cxx1yLoc))
1907  return false;
1908  return true;
1909 
1910  default:
1911  if (!isa<Expr>(S))
1912  break;
1913 
1914  // C++1y allows expression-statements.
1915  if (!Cxx1yLoc.isValid())
1916  Cxx1yLoc = S->getLocStart();
1917  return true;
1918  }
1919 
1920  SemaRef.Diag(S->getLocStart(), diag::err_constexpr_body_invalid_stmt)
1921  << isa<CXXConstructorDecl>(Dcl);
1922  return false;
1923 }
1924 
1925 /// Check the body for the given constexpr function declaration only contains
1926 /// the permitted types of statement. C++11 [dcl.constexpr]p3,p4.
1927 ///
1928 /// \return true if the body is OK, false if we have diagnosed a problem.
1930  if (isa<CXXTryStmt>(Body)) {
1931  // C++11 [dcl.constexpr]p3:
1932  // The definition of a constexpr function shall satisfy the following
1933  // constraints: [...]
1934  // - its function-body shall be = delete, = default, or a
1935  // compound-statement
1936  //
1937  // C++11 [dcl.constexpr]p4:
1938  // In the definition of a constexpr constructor, [...]
1939  // - its function-body shall not be a function-try-block;
1940  Diag(Body->getLocStart(), diag::err_constexpr_function_try_block)
1941  << isa<CXXConstructorDecl>(Dcl);
1942  return false;
1943  }
1944 
1945  SmallVector<SourceLocation, 4> ReturnStmts;
1946 
1947  // - its function-body shall be [...] a compound-statement that contains only
1948  // [... list of cases ...]
1949  CompoundStmt *CompBody = cast<CompoundStmt>(Body);
1950  SourceLocation Cxx1yLoc;
1951  for (auto *BodyIt : CompBody->body()) {
1952  if (!CheckConstexprFunctionStmt(*this, Dcl, BodyIt, ReturnStmts, Cxx1yLoc))
1953  return false;
1954  }
1955 
1956  if (Cxx1yLoc.isValid())
1957  Diag(Cxx1yLoc,
1958  getLangOpts().CPlusPlus14
1959  ? diag::warn_cxx11_compat_constexpr_body_invalid_stmt
1960  : diag::ext_constexpr_body_invalid_stmt)
1961  << isa<CXXConstructorDecl>(Dcl);
1962 
1963  if (const CXXConstructorDecl *Constructor
1964  = dyn_cast<CXXConstructorDecl>(Dcl)) {
1965  const CXXRecordDecl *RD = Constructor->getParent();
1966  // DR1359:
1967  // - every non-variant non-static data member and base class sub-object
1968  // shall be initialized;
1969  // DR1460:
1970  // - if the class is a union having variant members, exactly one of them
1971  // shall be initialized;
1972  if (RD->isUnion()) {
1973  if (Constructor->getNumCtorInitializers() == 0 &&
1974  RD->hasVariantMembers()) {
1975  Diag(Dcl->getLocation(), diag::err_constexpr_union_ctor_no_init);
1976  return false;
1977  }
1978  } else if (!Constructor->isDependentContext() &&
1979  !Constructor->isDelegatingConstructor()) {
1980  assert(RD->getNumVBases() == 0 && "constexpr ctor with virtual bases");
1981 
1982  // Skip detailed checking if we have enough initializers, and we would
1983  // allow at most one initializer per member.
1984  bool AnyAnonStructUnionMembers = false;
1985  unsigned Fields = 0;
1987  E = RD->field_end(); I != E; ++I, ++Fields) {
1988  if (I->isAnonymousStructOrUnion()) {
1989  AnyAnonStructUnionMembers = true;
1990  break;
1991  }
1992  }
1993  // DR1460:
1994  // - if the class is a union-like class, but is not a union, for each of
1995  // its anonymous union members having variant members, exactly one of
1996  // them shall be initialized;
1997  if (AnyAnonStructUnionMembers ||
1998  Constructor->getNumCtorInitializers() != RD->getNumBases() + Fields) {
1999  // Check initialization of non-static data members. Base classes are
2000  // always initialized so do not need to be checked. Dependent bases
2001  // might not have initializers in the member initializer list.
2002  llvm::SmallSet<Decl*, 16> Inits;
2003  for (const auto *I: Constructor->inits()) {
2004  if (FieldDecl *FD = I->getMember())
2005  Inits.insert(FD);
2006  else if (IndirectFieldDecl *ID = I->getIndirectMember())
2007  Inits.insert(ID->chain_begin(), ID->chain_end());
2008  }
2009 
2010  bool Diagnosed = false;
2011  for (auto *I : RD->fields())
2012  CheckConstexprCtorInitializer(*this, Dcl, I, Inits, Diagnosed);
2013  if (Diagnosed)
2014  return false;
2015  }
2016  }
2017  } else {
2018  if (ReturnStmts.empty()) {
2019  // C++1y doesn't require constexpr functions to contain a 'return'
2020  // statement. We still do, unless the return type might be void, because
2021  // otherwise if there's no return statement, the function cannot
2022  // be used in a core constant expression.
2023  bool OK = getLangOpts().CPlusPlus14 &&
2024  (Dcl->getReturnType()->isVoidType() ||
2025  Dcl->getReturnType()->isDependentType());
2026  Diag(Dcl->getLocation(),
2027  OK ? diag::warn_cxx11_compat_constexpr_body_no_return
2028  : diag::err_constexpr_body_no_return);
2029  if (!OK)
2030  return false;
2031  } else if (ReturnStmts.size() > 1) {
2032  Diag(ReturnStmts.back(),
2033  getLangOpts().CPlusPlus14
2034  ? diag::warn_cxx11_compat_constexpr_body_multiple_return
2035  : diag::ext_constexpr_body_multiple_return);
2036  for (unsigned I = 0; I < ReturnStmts.size() - 1; ++I)
2037  Diag(ReturnStmts[I], diag::note_constexpr_body_previous_return);
2038  }
2039  }
2040 
2041  // C++11 [dcl.constexpr]p5:
2042  // if no function argument values exist such that the function invocation
2043  // substitution would produce a constant expression, the program is
2044  // ill-formed; no diagnostic required.
2045  // C++11 [dcl.constexpr]p3:
2046  // - every constructor call and implicit conversion used in initializing the
2047  // return value shall be one of those allowed in a constant expression.
2048  // C++11 [dcl.constexpr]p4:
2049  // - every constructor involved in initializing non-static data members and
2050  // base class sub-objects shall be a constexpr constructor.
2052  if (!Expr::isPotentialConstantExpr(Dcl, Diags)) {
2053  Diag(Dcl->getLocation(), diag::ext_constexpr_function_never_constant_expr)
2054  << isa<CXXConstructorDecl>(Dcl);
2055  for (size_t I = 0, N = Diags.size(); I != N; ++I)
2056  Diag(Diags[I].first, Diags[I].second);
2057  // Don't return false here: we allow this for compatibility in
2058  // system headers.
2059  }
2060 
2061  return true;
2062 }
2063 
2064 /// isCurrentClassName - Determine whether the identifier II is the
2065 /// name of the class type currently being defined. In the case of
2066 /// nested classes, this will only return true if II is the name of
2067 /// the innermost class.
2069  const CXXScopeSpec *SS) {
2070  assert(getLangOpts().CPlusPlus && "No class names in C!");
2071 
2072  CXXRecordDecl *CurDecl;
2073  if (SS && SS->isSet() && !SS->isInvalid()) {
2074  DeclContext *DC = computeDeclContext(*SS, true);
2075  CurDecl = dyn_cast_or_null<CXXRecordDecl>(DC);
2076  } else
2077  CurDecl = dyn_cast_or_null<CXXRecordDecl>(CurContext);
2078 
2079  if (CurDecl && CurDecl->getIdentifier())
2080  return &II == CurDecl->getIdentifier();
2081  return false;
2082 }
2083 
2084 /// \brief Determine whether the identifier II is a typo for the name of
2085 /// the class type currently being defined. If so, update it to the identifier
2086 /// that should have been used.
2088  assert(getLangOpts().CPlusPlus && "No class names in C!");
2089 
2090  if (!getLangOpts().SpellChecking)
2091  return false;
2092 
2093  CXXRecordDecl *CurDecl;
2094  if (SS && SS->isSet() && !SS->isInvalid()) {
2095  DeclContext *DC = computeDeclContext(*SS, true);
2096  CurDecl = dyn_cast_or_null<CXXRecordDecl>(DC);
2097  } else
2098  CurDecl = dyn_cast_or_null<CXXRecordDecl>(CurContext);
2099 
2100  if (CurDecl && CurDecl->getIdentifier() && II != CurDecl->getIdentifier() &&
2101  3 * II->getName().edit_distance(CurDecl->getIdentifier()->getName())
2102  < II->getLength()) {
2103  II = CurDecl->getIdentifier();
2104  return true;
2105  }
2106 
2107  return false;
2108 }
2109 
2110 /// \brief Determine whether the given class is a base class of the given
2111 /// class, including looking at dependent bases.
2112 static bool findCircularInheritance(const CXXRecordDecl *Class,
2113  const CXXRecordDecl *Current) {
2115 
2116  Class = Class->getCanonicalDecl();
2117  while (true) {
2118  for (const auto &I : Current->bases()) {
2119  CXXRecordDecl *Base = I.getType()->getAsCXXRecordDecl();
2120  if (!Base)
2121  continue;
2122 
2123  Base = Base->getDefinition();
2124  if (!Base)
2125  continue;
2126 
2127  if (Base->getCanonicalDecl() == Class)
2128  return true;
2129 
2130  Queue.push_back(Base);
2131  }
2132 
2133  if (Queue.empty())
2134  return false;
2135 
2136  Current = Queue.pop_back_val();
2137  }
2138 
2139  return false;
2140 }
2141 
2142 /// \brief Check the validity of a C++ base class specifier.
2143 ///
2144 /// \returns a new CXXBaseSpecifier if well-formed, emits diagnostics
2145 /// and returns NULL otherwise.
2148  SourceRange SpecifierRange,
2149  bool Virtual, AccessSpecifier Access,
2150  TypeSourceInfo *TInfo,
2151  SourceLocation EllipsisLoc) {
2152  QualType BaseType = TInfo->getType();
2153 
2154  // C++ [class.union]p1:
2155  // A union shall not have base classes.
2156  if (Class->isUnion()) {
2157  Diag(Class->getLocation(), diag::err_base_clause_on_union)
2158  << SpecifierRange;
2159  return nullptr;
2160  }
2161 
2162  if (EllipsisLoc.isValid() &&
2164  Diag(EllipsisLoc, diag::err_pack_expansion_without_parameter_packs)
2165  << TInfo->getTypeLoc().getSourceRange();
2166  EllipsisLoc = SourceLocation();
2167  }
2168 
2169  SourceLocation BaseLoc = TInfo->getTypeLoc().getBeginLoc();
2170 
2171  if (BaseType->isDependentType()) {
2172  // Make sure that we don't have circular inheritance among our dependent
2173  // bases. For non-dependent bases, the check for completeness below handles
2174  // this.
2175  if (CXXRecordDecl *BaseDecl = BaseType->getAsCXXRecordDecl()) {
2176  if (BaseDecl->getCanonicalDecl() == Class->getCanonicalDecl() ||
2177  ((BaseDecl = BaseDecl->getDefinition()) &&
2178  findCircularInheritance(Class, BaseDecl))) {
2179  Diag(BaseLoc, diag::err_circular_inheritance)
2180  << BaseType << Context.getTypeDeclType(Class);
2181 
2182  if (BaseDecl->getCanonicalDecl() != Class->getCanonicalDecl())
2183  Diag(BaseDecl->getLocation(), diag::note_previous_decl)
2184  << BaseType;
2185 
2186  return nullptr;
2187  }
2188  }
2189 
2190  return new (Context) CXXBaseSpecifier(SpecifierRange, Virtual,
2191  Class->getTagKind() == TTK_Class,
2192  Access, TInfo, EllipsisLoc);
2193  }
2194 
2195  // Base specifiers must be record types.
2196  if (!BaseType->isRecordType()) {
2197  Diag(BaseLoc, diag::err_base_must_be_class) << SpecifierRange;
2198  return nullptr;
2199  }
2200 
2201  // C++ [class.union]p1:
2202  // A union shall not be used as a base class.
2203  if (BaseType->isUnionType()) {
2204  Diag(BaseLoc, diag::err_union_as_base_class) << SpecifierRange;
2205  return nullptr;
2206  }
2207 
2208  // For the MS ABI, propagate DLL attributes to base class templates.
2209  if (Context.getTargetInfo().getCXXABI().isMicrosoft()) {
2210  if (Attr *ClassAttr = getDLLAttr(Class)) {
2211  if (auto *BaseTemplate = dyn_cast_or_null<ClassTemplateSpecializationDecl>(
2212  BaseType->getAsCXXRecordDecl())) {
2213  propagateDLLAttrToBaseClassTemplate(Class, ClassAttr, BaseTemplate,
2214  BaseLoc);
2215  }
2216  }
2217  }
2218 
2219  // C++ [class.derived]p2:
2220  // The class-name in a base-specifier shall not be an incompletely
2221  // defined class.
2222  if (RequireCompleteType(BaseLoc, BaseType,
2223  diag::err_incomplete_base_class, SpecifierRange)) {
2224  Class->setInvalidDecl();
2225  return nullptr;
2226  }
2227 
2228  // If the base class is polymorphic or isn't empty, the new one is/isn't, too.
2229  RecordDecl *BaseDecl = BaseType->getAs<RecordType>()->getDecl();
2230  assert(BaseDecl && "Record type has no declaration");
2231  BaseDecl = BaseDecl->getDefinition();
2232  assert(BaseDecl && "Base type is not incomplete, but has no definition");
2233  CXXRecordDecl *CXXBaseDecl = cast<CXXRecordDecl>(BaseDecl);
2234  assert(CXXBaseDecl && "Base type is not a C++ type");
2235 
2236  // A class which contains a flexible array member is not suitable for use as a
2237  // base class:
2238  // - If the layout determines that a base comes before another base,
2239  // the flexible array member would index into the subsequent base.
2240  // - If the layout determines that base comes before the derived class,
2241  // the flexible array member would index into the derived class.
2242  if (CXXBaseDecl->hasFlexibleArrayMember()) {
2243  Diag(BaseLoc, diag::err_base_class_has_flexible_array_member)
2244  << CXXBaseDecl->getDeclName();
2245  return nullptr;
2246  }
2247 
2248  // C++ [class]p3:
2249  // If a class is marked final and it appears as a base-type-specifier in
2250  // base-clause, the program is ill-formed.
2251  if (FinalAttr *FA = CXXBaseDecl->getAttr<FinalAttr>()) {
2252  Diag(BaseLoc, diag::err_class_marked_final_used_as_base)
2253  << CXXBaseDecl->getDeclName()
2254  << FA->isSpelledAsSealed();
2255  Diag(CXXBaseDecl->getLocation(), diag::note_entity_declared_at)
2256  << CXXBaseDecl->getDeclName() << FA->getRange();
2257  return nullptr;
2258  }
2259 
2260  if (BaseDecl->isInvalidDecl())
2261  Class->setInvalidDecl();
2262 
2263  // Create the base specifier.
2264  return new (Context) CXXBaseSpecifier(SpecifierRange, Virtual,
2265  Class->getTagKind() == TTK_Class,
2266  Access, TInfo, EllipsisLoc);
2267 }
2268 
2269 /// ActOnBaseSpecifier - Parsed a base specifier. A base specifier is
2270 /// one entry in the base class list of a class specifier, for
2271 /// example:
2272 /// class foo : public bar, virtual private baz {
2273 /// 'public bar' and 'virtual private baz' are each base-specifiers.
2274 BaseResult
2275 Sema::ActOnBaseSpecifier(Decl *classdecl, SourceRange SpecifierRange,
2276  ParsedAttributes &Attributes,
2277  bool Virtual, AccessSpecifier Access,
2278  ParsedType basetype, SourceLocation BaseLoc,
2279  SourceLocation EllipsisLoc) {
2280  if (!classdecl)
2281  return true;
2282 
2283  AdjustDeclIfTemplate(classdecl);
2284  CXXRecordDecl *Class = dyn_cast<CXXRecordDecl>(classdecl);
2285  if (!Class)
2286  return true;
2287 
2288  // We haven't yet attached the base specifiers.
2289  Class->setIsParsingBaseSpecifiers();
2290 
2291  // We do not support any C++11 attributes on base-specifiers yet.
2292  // Diagnose any attributes we see.
2293  if (!Attributes.empty()) {
2294  for (AttributeList *Attr = Attributes.getList(); Attr;
2295  Attr = Attr->getNext()) {
2296  if (Attr->isInvalid() ||
2298  continue;
2299  Diag(Attr->getLoc(),
2301  ? diag::warn_unknown_attribute_ignored
2302  : diag::err_base_specifier_attribute)
2303  << Attr->getName();
2304  }
2305  }
2306 
2307  TypeSourceInfo *TInfo = nullptr;
2308  GetTypeFromParser(basetype, &TInfo);
2309 
2310  if (EllipsisLoc.isInvalid() &&
2311  DiagnoseUnexpandedParameterPack(SpecifierRange.getBegin(), TInfo,
2312  UPPC_BaseType))
2313  return true;
2314 
2315  if (CXXBaseSpecifier *BaseSpec = CheckBaseSpecifier(Class, SpecifierRange,
2316  Virtual, Access, TInfo,
2317  EllipsisLoc))
2318  return BaseSpec;
2319  else
2320  Class->setInvalidDecl();
2321 
2322  return true;
2323 }
2324 
2325 /// Use small set to collect indirect bases. As this is only used
2326 /// locally, there's no need to abstract the small size parameter.
2327 typedef llvm::SmallPtrSet<QualType, 4> IndirectBaseSet;
2328 
2329 /// \brief Recursively add the bases of Type. Don't add Type itself.
2330 static void
2331 NoteIndirectBases(ASTContext &Context, IndirectBaseSet &Set,
2332  const QualType &Type)
2333 {
2334  // Even though the incoming type is a base, it might not be
2335  // a class -- it could be a template parm, for instance.
2336  if (auto Rec = Type->getAs<RecordType>()) {
2337  auto Decl = Rec->getAsCXXRecordDecl();
2338 
2339  // Iterate over its bases.
2340  for (const auto &BaseSpec : Decl->bases()) {
2341  QualType Base = Context.getCanonicalType(BaseSpec.getType())
2342  .getUnqualifiedType();
2343  if (Set.insert(Base).second)
2344  // If we've not already seen it, recurse.
2345  NoteIndirectBases(Context, Set, Base);
2346  }
2347  }
2348 }
2349 
2350 /// \brief Performs the actual work of attaching the given base class
2351 /// specifiers to a C++ class.
2354  if (Bases.empty())
2355  return false;
2356 
2357  // Used to keep track of which base types we have already seen, so
2358  // that we can properly diagnose redundant direct base types. Note
2359  // that the key is always the unqualified canonical type of the base
2360  // class.
2361  std::map<QualType, CXXBaseSpecifier*, QualTypeOrdering> KnownBaseTypes;
2362 
2363  // Used to track indirect bases so we can see if a direct base is
2364  // ambiguous.
2365  IndirectBaseSet IndirectBaseTypes;
2366 
2367  // Copy non-redundant base specifiers into permanent storage.
2368  unsigned NumGoodBases = 0;
2369  bool Invalid = false;
2370  for (unsigned idx = 0; idx < Bases.size(); ++idx) {
2371  QualType NewBaseType
2372  = Context.getCanonicalType(Bases[idx]->getType());
2373  NewBaseType = NewBaseType.getLocalUnqualifiedType();
2374 
2375  CXXBaseSpecifier *&KnownBase = KnownBaseTypes[NewBaseType];
2376  if (KnownBase) {
2377  // C++ [class.mi]p3:
2378  // A class shall not be specified as a direct base class of a
2379  // derived class more than once.
2380  Diag(Bases[idx]->getLocStart(),
2381  diag::err_duplicate_base_class)
2382  << KnownBase->getType()
2383  << Bases[idx]->getSourceRange();
2384 
2385  // Delete the duplicate base class specifier; we're going to
2386  // overwrite its pointer later.
2387  Context.Deallocate(Bases[idx]);
2388 
2389  Invalid = true;
2390  } else {
2391  // Okay, add this new base class.
2392  KnownBase = Bases[idx];
2393  Bases[NumGoodBases++] = Bases[idx];
2394 
2395  // Note this base's direct & indirect bases, if there could be ambiguity.
2396  if (Bases.size() > 1)
2397  NoteIndirectBases(Context, IndirectBaseTypes, NewBaseType);
2398 
2399  if (const RecordType *Record = NewBaseType->getAs<RecordType>()) {
2400  const CXXRecordDecl *RD = cast<CXXRecordDecl>(Record->getDecl());
2401  if (Class->isInterface() &&
2402  (!RD->isInterfaceLike() ||
2403  KnownBase->getAccessSpecifier() != AS_public)) {
2404  // The Microsoft extension __interface does not permit bases that
2405  // are not themselves public interfaces.
2406  Diag(KnownBase->getLocStart(), diag::err_invalid_base_in_interface)
2407  << getRecordDiagFromTagKind(RD->getTagKind()) << RD->getName()
2408  << RD->getSourceRange();
2409  Invalid = true;
2410  }
2411  if (RD->hasAttr<WeakAttr>())
2412  Class->addAttr(WeakAttr::CreateImplicit(Context));
2413  }
2414  }
2415  }
2416 
2417  // Attach the remaining base class specifiers to the derived class.
2418  Class->setBases(Bases.data(), NumGoodBases);
2419 
2420  for (unsigned idx = 0; idx < NumGoodBases; ++idx) {
2421  // Check whether this direct base is inaccessible due to ambiguity.
2422  QualType BaseType = Bases[idx]->getType();
2423  CanQualType CanonicalBase = Context.getCanonicalType(BaseType)
2424  .getUnqualifiedType();
2425 
2426  if (IndirectBaseTypes.count(CanonicalBase)) {
2427  CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/true,
2428  /*DetectVirtual=*/true);
2429  bool found
2430  = Class->isDerivedFrom(CanonicalBase->getAsCXXRecordDecl(), Paths);
2431  assert(found);
2432  (void)found;
2433 
2434  if (Paths.isAmbiguous(CanonicalBase))
2435  Diag(Bases[idx]->getLocStart (), diag::warn_inaccessible_base_class)
2436  << BaseType << getAmbiguousPathsDisplayString(Paths)
2437  << Bases[idx]->getSourceRange();
2438  else
2439  assert(Bases[idx]->isVirtual());
2440  }
2441 
2442  // Delete the base class specifier, since its data has been copied
2443  // into the CXXRecordDecl.
2444  Context.Deallocate(Bases[idx]);
2445  }
2446 
2447  return Invalid;
2448 }
2449 
2450 /// ActOnBaseSpecifiers - Attach the given base specifiers to the
2451 /// class, after checking whether there are any duplicate base
2452 /// classes.
2453 void Sema::ActOnBaseSpecifiers(Decl *ClassDecl,
2455  if (!ClassDecl || Bases.empty())
2456  return;
2457 
2458  AdjustDeclIfTemplate(ClassDecl);
2459  AttachBaseSpecifiers(cast<CXXRecordDecl>(ClassDecl), Bases);
2460 }
2461 
2462 /// \brief Determine whether the type \p Derived is a C++ class that is
2463 /// derived from the type \p Base.
2465  if (!getLangOpts().CPlusPlus)
2466  return false;
2467 
2468  CXXRecordDecl *DerivedRD = Derived->getAsCXXRecordDecl();
2469  if (!DerivedRD)
2470  return false;
2471 
2472  CXXRecordDecl *BaseRD = Base->getAsCXXRecordDecl();
2473  if (!BaseRD)
2474  return false;
2475 
2476  // If either the base or the derived type is invalid, don't try to
2477  // check whether one is derived from the other.
2478  if (BaseRD->isInvalidDecl() || DerivedRD->isInvalidDecl())
2479  return false;
2480 
2481  // FIXME: In a modules build, do we need the entire path to be visible for us
2482  // to be able to use the inheritance relationship?
2483  if (!isCompleteType(Loc, Derived) && !DerivedRD->isBeingDefined())
2484  return false;
2485 
2486  return DerivedRD->isDerivedFrom(BaseRD);
2487 }
2488 
2489 /// \brief Determine whether the type \p Derived is a C++ class that is
2490 /// derived from the type \p Base.
2492  CXXBasePaths &Paths) {
2493  if (!getLangOpts().CPlusPlus)
2494  return false;
2495 
2496  CXXRecordDecl *DerivedRD = Derived->getAsCXXRecordDecl();
2497  if (!DerivedRD)
2498  return false;
2499 
2500  CXXRecordDecl *BaseRD = Base->getAsCXXRecordDecl();
2501  if (!BaseRD)
2502  return false;
2503 
2504  if (!isCompleteType(Loc, Derived) && !DerivedRD->isBeingDefined())
2505  return false;
2506 
2507  return DerivedRD->isDerivedFrom(BaseRD, Paths);
2508 }
2509 
2510 static void BuildBasePathArray(const CXXBasePath &Path,
2511  CXXCastPath &BasePathArray) {
2512  // We first go backward and check if we have a virtual base.
2513  // FIXME: It would be better if CXXBasePath had the base specifier for
2514  // the nearest virtual base.
2515  unsigned Start = 0;
2516  for (unsigned I = Path.size(); I != 0; --I) {
2517  if (Path[I - 1].Base->isVirtual()) {
2518  Start = I - 1;
2519  break;
2520  }
2521  }
2522 
2523  // Now add all bases.
2524  for (unsigned I = Start, E = Path.size(); I != E; ++I)
2525  BasePathArray.push_back(const_cast<CXXBaseSpecifier*>(Path[I].Base));
2526 }
2527 
2528 
2530  CXXCastPath &BasePathArray) {
2531  assert(BasePathArray.empty() && "Base path array must be empty!");
2532  assert(Paths.isRecordingPaths() && "Must record paths!");
2533  return ::BuildBasePathArray(Paths.front(), BasePathArray);
2534 }
2535 /// CheckDerivedToBaseConversion - Check whether the Derived-to-Base
2536 /// conversion (where Derived and Base are class types) is
2537 /// well-formed, meaning that the conversion is unambiguous (and
2538 /// that all of the base classes are accessible). Returns true
2539 /// and emits a diagnostic if the code is ill-formed, returns false
2540 /// otherwise. Loc is the location where this routine should point to
2541 /// if there is an error, and Range is the source range to highlight
2542 /// if there is an error.
2543 ///
2544 /// If either InaccessibleBaseID or AmbigiousBaseConvID are 0, then the
2545 /// diagnostic for the respective type of error will be suppressed, but the
2546 /// check for ill-formed code will still be performed.
2547 bool
2549  unsigned InaccessibleBaseID,
2550  unsigned AmbigiousBaseConvID,
2551  SourceLocation Loc, SourceRange Range,
2552  DeclarationName Name,
2553  CXXCastPath *BasePath,
2554  bool IgnoreAccess) {
2555  // First, determine whether the path from Derived to Base is
2556  // ambiguous. This is slightly more expensive than checking whether
2557  // the Derived to Base conversion exists, because here we need to
2558  // explore multiple paths to determine if there is an ambiguity.
2559  CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/true,
2560  /*DetectVirtual=*/false);
2561  bool DerivationOkay = IsDerivedFrom(Loc, Derived, Base, Paths);
2562  if (!DerivationOkay)
2563  return true;
2564 
2565  const CXXBasePath *Path = nullptr;
2566  if (!Paths.isAmbiguous(Context.getCanonicalType(Base).getUnqualifiedType()))
2567  Path = &Paths.front();
2568 
2569  // For MSVC compatibility, check if Derived directly inherits from Base. Clang
2570  // warns about this hierarchy under -Winaccessible-base, but MSVC allows the
2571  // user to access such bases.
2572  if (!Path && getLangOpts().MSVCCompat) {
2573  for (const CXXBasePath &PossiblePath : Paths) {
2574  if (PossiblePath.size() == 1) {
2575  Path = &PossiblePath;
2576  if (AmbigiousBaseConvID)
2577  Diag(Loc, diag::ext_ms_ambiguous_direct_base)
2578  << Base << Derived << Range;
2579  break;
2580  }
2581  }
2582  }
2583 
2584  if (Path) {
2585  if (!IgnoreAccess) {
2586  // Check that the base class can be accessed.
2587  switch (
2588  CheckBaseClassAccess(Loc, Base, Derived, *Path, InaccessibleBaseID)) {
2589  case AR_inaccessible:
2590  return true;
2591  case AR_accessible:
2592  case AR_dependent:
2593  case AR_delayed:
2594  break;
2595  }
2596  }
2597 
2598  // Build a base path if necessary.
2599  if (BasePath)
2600  ::BuildBasePathArray(*Path, *BasePath);
2601  return false;
2602  }
2603 
2604  if (AmbigiousBaseConvID) {
2605  // We know that the derived-to-base conversion is ambiguous, and
2606  // we're going to produce a diagnostic. Perform the derived-to-base
2607  // search just one more time to compute all of the possible paths so
2608  // that we can print them out. This is more expensive than any of
2609  // the previous derived-to-base checks we've done, but at this point
2610  // performance isn't as much of an issue.
2611  Paths.clear();
2612  Paths.setRecordingPaths(true);
2613  bool StillOkay = IsDerivedFrom(Loc, Derived, Base, Paths);
2614  assert(StillOkay && "Can only be used with a derived-to-base conversion");
2615  (void)StillOkay;
2616 
2617  // Build up a textual representation of the ambiguous paths, e.g.,
2618  // D -> B -> A, that will be used to illustrate the ambiguous
2619  // conversions in the diagnostic. We only print one of the paths
2620  // to each base class subobject.
2621  std::string PathDisplayStr = getAmbiguousPathsDisplayString(Paths);
2622 
2623  Diag(Loc, AmbigiousBaseConvID)
2624  << Derived << Base << PathDisplayStr << Range << Name;
2625  }
2626  return true;
2627 }
2628 
2629 bool
2631  SourceLocation Loc, SourceRange Range,
2632  CXXCastPath *BasePath,
2633  bool IgnoreAccess) {
2634  return CheckDerivedToBaseConversion(
2635  Derived, Base, diag::err_upcast_to_inaccessible_base,
2636  diag::err_ambiguous_derived_to_base_conv, Loc, Range, DeclarationName(),
2637  BasePath, IgnoreAccess);
2638 }
2639 
2640 
2641 /// @brief Builds a string representing ambiguous paths from a
2642 /// specific derived class to different subobjects of the same base
2643 /// class.
2644 ///
2645 /// This function builds a string that can be used in error messages
2646 /// to show the different paths that one can take through the
2647 /// inheritance hierarchy to go from the derived class to different
2648 /// subobjects of a base class. The result looks something like this:
2649 /// @code
2650 /// struct D -> struct B -> struct A
2651 /// struct D -> struct C -> struct A
2652 /// @endcode
2654  std::string PathDisplayStr;
2655  std::set<unsigned> DisplayedPaths;
2656  for (CXXBasePaths::paths_iterator Path = Paths.begin();
2657  Path != Paths.end(); ++Path) {
2658  if (DisplayedPaths.insert(Path->back().SubobjectNumber).second) {
2659  // We haven't displayed a path to this particular base
2660  // class subobject yet.
2661  PathDisplayStr += "\n ";
2662  PathDisplayStr += Context.getTypeDeclType(Paths.getOrigin()).getAsString();
2663  for (CXXBasePath::const_iterator Element = Path->begin();
2664  Element != Path->end(); ++Element)
2665  PathDisplayStr += " -> " + Element->Base->getType().getAsString();
2666  }
2667  }
2668 
2669  return PathDisplayStr;
2670 }
2671 
2672 //===----------------------------------------------------------------------===//
2673 // C++ class member Handling
2674 //===----------------------------------------------------------------------===//
2675 
2676 /// ActOnAccessSpecifier - Parsed an access specifier followed by a colon.
2678  SourceLocation ASLoc,
2680  AttributeList *Attrs) {
2681  assert(Access != AS_none && "Invalid kind for syntactic access specifier!");
2682  AccessSpecDecl *ASDecl = AccessSpecDecl::Create(Context, Access, CurContext,
2683  ASLoc, ColonLoc);
2684  CurContext->addHiddenDecl(ASDecl);
2685  return ProcessAccessDeclAttributeList(ASDecl, Attrs);
2686 }
2687 
2688 /// CheckOverrideControl - Check C++11 override control semantics.
2690  if (D->isInvalidDecl())
2691  return;
2692 
2693  // We only care about "override" and "final" declarations.
2694  if (!D->hasAttr<OverrideAttr>() && !D->hasAttr<FinalAttr>())
2695  return;
2696 
2697  CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(D);
2698 
2699  // We can't check dependent instance methods.
2700  if (MD && MD->isInstance() &&
2701  (MD->getParent()->hasAnyDependentBases() ||
2702  MD->getType()->isDependentType()))
2703  return;
2704 
2705  if (MD && !MD->isVirtual()) {
2706  // If we have a non-virtual method, check if if hides a virtual method.
2707  // (In that case, it's most likely the method has the wrong type.)
2708  SmallVector<CXXMethodDecl *, 8> OverloadedMethods;
2709  FindHiddenVirtualMethods(MD, OverloadedMethods);
2710 
2711  if (!OverloadedMethods.empty()) {
2712  if (OverrideAttr *OA = D->getAttr<OverrideAttr>()) {
2713  Diag(OA->getLocation(),
2714  diag::override_keyword_hides_virtual_member_function)
2715  << "override" << (OverloadedMethods.size() > 1);
2716  } else if (FinalAttr *FA = D->getAttr<FinalAttr>()) {
2717  Diag(FA->getLocation(),
2718  diag::override_keyword_hides_virtual_member_function)
2719  << (FA->isSpelledAsSealed() ? "sealed" : "final")
2720  << (OverloadedMethods.size() > 1);
2721  }
2722  NoteHiddenVirtualMethods(MD, OverloadedMethods);
2723  MD->setInvalidDecl();
2724  return;
2725  }
2726  // Fall through into the general case diagnostic.
2727  // FIXME: We might want to attempt typo correction here.
2728  }
2729 
2730  if (!MD || !MD->isVirtual()) {
2731  if (OverrideAttr *OA = D->getAttr<OverrideAttr>()) {
2732  Diag(OA->getLocation(),
2733  diag::override_keyword_only_allowed_on_virtual_member_functions)
2734  << "override" << FixItHint::CreateRemoval(OA->getLocation());
2735  D->dropAttr<OverrideAttr>();
2736  }
2737  if (FinalAttr *FA = D->getAttr<FinalAttr>()) {
2738  Diag(FA->getLocation(),
2739  diag::override_keyword_only_allowed_on_virtual_member_functions)
2740  << (FA->isSpelledAsSealed() ? "sealed" : "final")
2741  << FixItHint::CreateRemoval(FA->getLocation());
2742  D->dropAttr<FinalAttr>();
2743  }
2744  return;
2745  }
2746 
2747  // C++11 [class.virtual]p5:
2748  // If a function is marked with the virt-specifier override and
2749  // does not override a member function of a base class, the program is
2750  // ill-formed.
2751  bool HasOverriddenMethods =
2753  if (MD->hasAttr<OverrideAttr>() && !HasOverriddenMethods)
2754  Diag(MD->getLocation(), diag::err_function_marked_override_not_overriding)
2755  << MD->getDeclName();
2756 }
2757 
2759  if (D->isInvalidDecl() || D->hasAttr<OverrideAttr>())
2760  return;
2761  CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(D);
2762  if (!MD || MD->isImplicit() || MD->hasAttr<FinalAttr>())
2763  return;
2764 
2765  SourceLocation Loc = MD->getLocation();
2766  SourceLocation SpellingLoc = Loc;
2767  if (getSourceManager().isMacroArgExpansion(Loc))
2768  SpellingLoc = getSourceManager().getImmediateExpansionRange(Loc).first;
2769  SpellingLoc = getSourceManager().getSpellingLoc(SpellingLoc);
2770  if (SpellingLoc.isValid() && getSourceManager().isInSystemHeader(SpellingLoc))
2771  return;
2772 
2773  if (MD->size_overridden_methods() > 0) {
2774  unsigned DiagID = isa<CXXDestructorDecl>(MD)
2775  ? diag::warn_destructor_marked_not_override_overriding
2776  : diag::warn_function_marked_not_override_overriding;
2777  Diag(MD->getLocation(), DiagID) << MD->getDeclName();
2778  const CXXMethodDecl *OMD = *MD->begin_overridden_methods();
2779  Diag(OMD->getLocation(), diag::note_overridden_virtual_function);
2780  }
2781 }
2782 
2783 /// CheckIfOverriddenFunctionIsMarkedFinal - Checks whether a virtual member
2784 /// function overrides a virtual member function marked 'final', according to
2785 /// C++11 [class.virtual]p4.
2787  const CXXMethodDecl *Old) {
2788  FinalAttr *FA = Old->getAttr<FinalAttr>();
2789  if (!FA)
2790  return false;
2791 
2792  Diag(New->getLocation(), diag::err_final_function_overridden)
2793  << New->getDeclName()
2794  << FA->isSpelledAsSealed();
2795  Diag(Old->getLocation(), diag::note_overridden_virtual_function);
2796  return true;
2797 }
2798 
2799 static bool InitializationHasSideEffects(const FieldDecl &FD) {
2800  const Type *T = FD.getType()->getBaseElementTypeUnsafe();
2801  // FIXME: Destruction of ObjC lifetime types has side-effects.
2802  if (const CXXRecordDecl *RD = T->getAsCXXRecordDecl())
2803  return !RD->isCompleteDefinition() ||
2804  !RD->hasTrivialDefaultConstructor() ||
2805  !RD->hasTrivialDestructor();
2806  return false;
2807 }
2808 
2810  for (AttributeList *it = list; it != nullptr; it = it->getNext())
2811  if (it->isDeclspecPropertyAttribute())
2812  return it;
2813  return nullptr;
2814 }
2815 
2816 // Check if there is a field shadowing.
2817 void Sema::CheckShadowInheritedFields(const SourceLocation &Loc,
2818  DeclarationName FieldName,
2819  const CXXRecordDecl *RD) {
2820  if (Diags.isIgnored(diag::warn_shadow_field, Loc))
2821  return;
2822 
2823  // To record a shadowed field in a base
2824  std::map<CXXRecordDecl*, NamedDecl*> Bases;
2825  auto FieldShadowed = [&](const CXXBaseSpecifier *Specifier,
2826  CXXBasePath &Path) {
2827  const auto Base = Specifier->getType()->getAsCXXRecordDecl();
2828  // Record an ambiguous path directly
2829  if (Bases.find(Base) != Bases.end())
2830  return true;
2831  for (const auto Field : Base->lookup(FieldName)) {
2832  if ((isa<FieldDecl>(Field) || isa<IndirectFieldDecl>(Field)) &&
2833  Field->getAccess() != AS_private) {
2834  assert(Field->getAccess() != AS_none);
2835  assert(Bases.find(Base) == Bases.end());
2836  Bases[Base] = Field;
2837  return true;
2838  }
2839  }
2840  return false;
2841  };
2842 
2843  CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/true,
2844  /*DetectVirtual=*/true);
2845  if (!RD->lookupInBases(FieldShadowed, Paths))
2846  return;
2847 
2848  for (const auto &P : Paths) {
2849  auto Base = P.back().Base->getType()->getAsCXXRecordDecl();
2850  auto It = Bases.find(Base);
2851  // Skip duplicated bases
2852  if (It == Bases.end())
2853  continue;
2854  auto BaseField = It->second;
2855  assert(BaseField->getAccess() != AS_private);
2856  if (AS_none !=
2857  CXXRecordDecl::MergeAccess(P.Access, BaseField->getAccess())) {
2858  Diag(Loc, diag::warn_shadow_field)
2859  << FieldName.getAsString() << RD->getName() << Base->getName();
2860  Diag(BaseField->getLocation(), diag::note_shadow_field);
2861  Bases.erase(It);
2862  }
2863  }
2864 }
2865 
2866 /// ActOnCXXMemberDeclarator - This is invoked when a C++ class member
2867 /// declarator is parsed. 'AS' is the access specifier, 'BW' specifies the
2868 /// bitfield width if there is one, 'InitExpr' specifies the initializer if
2869 /// one has been parsed, and 'InitStyle' is set if an in-class initializer is
2870 /// present (but parsing it has been deferred).
2871 NamedDecl *
2873  MultiTemplateParamsArg TemplateParameterLists,
2874  Expr *BW, const VirtSpecifiers &VS,
2875  InClassInitStyle InitStyle) {
2876  const DeclSpec &DS = D.getDeclSpec();
2877  DeclarationNameInfo NameInfo = GetNameForDeclarator(D);
2878  DeclarationName Name = NameInfo.getName();
2879  SourceLocation Loc = NameInfo.getLoc();
2880 
2881  // For anonymous bitfields, the location should point to the type.
2882  if (Loc.isInvalid())
2883  Loc = D.getLocStart();
2884 
2885  Expr *BitWidth = static_cast<Expr*>(BW);
2886 
2887  assert(isa<CXXRecordDecl>(CurContext));
2888  assert(!DS.isFriendSpecified());
2889 
2890  bool isFunc = D.isDeclarationOfFunction();
2891  AttributeList *MSPropertyAttr =
2893 
2894  if (cast<CXXRecordDecl>(CurContext)->isInterface()) {
2895  // The Microsoft extension __interface only permits public member functions
2896  // and prohibits constructors, destructors, operators, non-public member
2897  // functions, static methods and data members.
2898  unsigned InvalidDecl;
2899  bool ShowDeclName = true;
2900  if (!isFunc &&
2901  (DS.getStorageClassSpec() == DeclSpec::SCS_typedef || MSPropertyAttr))
2902  InvalidDecl = 0;
2903  else if (!isFunc)
2904  InvalidDecl = 1;
2905  else if (AS != AS_public)
2906  InvalidDecl = 2;
2907  else if (DS.getStorageClassSpec() == DeclSpec::SCS_static)
2908  InvalidDecl = 3;
2909  else switch (Name.getNameKind()) {
2911  InvalidDecl = 4;
2912  ShowDeclName = false;
2913  break;
2914 
2916  InvalidDecl = 5;
2917  ShowDeclName = false;
2918  break;
2919 
2922  InvalidDecl = 6;
2923  break;
2924 
2925  default:
2926  InvalidDecl = 0;
2927  break;
2928  }
2929 
2930  if (InvalidDecl) {
2931  if (ShowDeclName)
2932  Diag(Loc, diag::err_invalid_member_in_interface)
2933  << (InvalidDecl-1) << Name;
2934  else
2935  Diag(Loc, diag::err_invalid_member_in_interface)
2936  << (InvalidDecl-1) << "";
2937  return nullptr;
2938  }
2939  }
2940 
2941  // C++ 9.2p6: A member shall not be declared to have automatic storage
2942  // duration (auto, register) or with the extern storage-class-specifier.
2943  // C++ 7.1.1p8: The mutable specifier can be applied only to names of class
2944  // data members and cannot be applied to names declared const or static,
2945  // and cannot be applied to reference members.
2946  switch (DS.getStorageClassSpec()) {
2948  case DeclSpec::SCS_typedef:
2949  case DeclSpec::SCS_static:
2950  break;
2951  case DeclSpec::SCS_mutable:
2952  if (isFunc) {
2953  Diag(DS.getStorageClassSpecLoc(), diag::err_mutable_function);
2954 
2955  // FIXME: It would be nicer if the keyword was ignored only for this
2956  // declarator. Otherwise we could get follow-up errors.
2958  }
2959  break;
2960  default:
2962  diag::err_storageclass_invalid_for_member);
2964  break;
2965  }
2966 
2967  bool isInstField = ((DS.getStorageClassSpec() == DeclSpec::SCS_unspecified ||
2969  !isFunc);
2970 
2971  if (DS.isConstexprSpecified() && isInstField) {
2973  Diag(DS.getConstexprSpecLoc(), diag::err_invalid_constexpr_member);
2974  SourceLocation ConstexprLoc = DS.getConstexprSpecLoc();
2975  if (InitStyle == ICIS_NoInit) {
2976  B << 0 << 0;
2978  B << FixItHint::CreateRemoval(ConstexprLoc);
2979  else {
2980  B << FixItHint::CreateReplacement(ConstexprLoc, "const");
2982  const char *PrevSpec;
2983  unsigned DiagID;
2984  bool Failed = D.getMutableDeclSpec().SetTypeQual(
2985  DeclSpec::TQ_const, ConstexprLoc, PrevSpec, DiagID, getLangOpts());
2986  (void)Failed;
2987  assert(!Failed && "Making a constexpr member const shouldn't fail");
2988  }
2989  } else {
2990  B << 1;
2991  const char *PrevSpec;
2992  unsigned DiagID;
2994  *this, DeclSpec::SCS_static, ConstexprLoc, PrevSpec, DiagID,
2995  Context.getPrintingPolicy())) {
2996  assert(DS.getStorageClassSpec() == DeclSpec::SCS_mutable &&
2997  "This is the only DeclSpec that should fail to be applied");
2998  B << 1;
2999  } else {
3000  B << 0 << FixItHint::CreateInsertion(ConstexprLoc, "static ");
3001  isInstField = false;
3002  }
3003  }
3004  }
3005 
3006  NamedDecl *Member;
3007  if (isInstField) {
3008  CXXScopeSpec &SS = D.getCXXScopeSpec();
3009 
3010  // Data members must have identifiers for names.
3011  if (!Name.isIdentifier()) {
3012  Diag(Loc, diag::err_bad_variable_name)
3013  << Name;
3014  return nullptr;
3015  }
3016 
3017  IdentifierInfo *II = Name.getAsIdentifierInfo();
3018 
3019  // Member field could not be with "template" keyword.
3020  // So TemplateParameterLists should be empty in this case.
3021  if (TemplateParameterLists.size()) {
3022  TemplateParameterList* TemplateParams = TemplateParameterLists[0];
3023  if (TemplateParams->size()) {
3024  // There is no such thing as a member field template.
3025  Diag(D.getIdentifierLoc(), diag::err_template_member)
3026  << II
3027  << SourceRange(TemplateParams->getTemplateLoc(),
3028  TemplateParams->getRAngleLoc());
3029  } else {
3030  // There is an extraneous 'template<>' for this member.
3031  Diag(TemplateParams->getTemplateLoc(),
3032  diag::err_template_member_noparams)
3033  << II
3034  << SourceRange(TemplateParams->getTemplateLoc(),
3035  TemplateParams->getRAngleLoc());
3036  }
3037  return nullptr;
3038  }
3039 
3040  if (SS.isSet() && !SS.isInvalid()) {
3041  // The user provided a superfluous scope specifier inside a class
3042  // definition:
3043  //
3044  // class X {
3045  // int X::member;
3046  // };
3047  if (DeclContext *DC = computeDeclContext(SS, false))
3048  diagnoseQualifiedDeclaration(SS, DC, Name, D.getIdentifierLoc());
3049  else
3050  Diag(D.getIdentifierLoc(), diag::err_member_qualification)
3051  << Name << SS.getRange();
3052 
3053  SS.clear();
3054  }
3055 
3056  if (MSPropertyAttr) {
3057  Member = HandleMSProperty(S, cast<CXXRecordDecl>(CurContext), Loc, D,
3058  BitWidth, InitStyle, AS, MSPropertyAttr);
3059  if (!Member)
3060  return nullptr;
3061  isInstField = false;
3062  } else {
3063  Member = HandleField(S, cast<CXXRecordDecl>(CurContext), Loc, D,
3064  BitWidth, InitStyle, AS);
3065  if (!Member)
3066  return nullptr;
3067  }
3068 
3069  CheckShadowInheritedFields(Loc, Name, cast<CXXRecordDecl>(CurContext));
3070  } else {
3071  Member = HandleDeclarator(S, D, TemplateParameterLists);
3072  if (!Member)
3073  return nullptr;
3074 
3075  // Non-instance-fields can't have a bitfield.
3076  if (BitWidth) {
3077  if (Member->isInvalidDecl()) {
3078  // don't emit another diagnostic.
3079  } else if (isa<VarDecl>(Member) || isa<VarTemplateDecl>(Member)) {
3080  // C++ 9.6p3: A bit-field shall not be a static member.
3081  // "static member 'A' cannot be a bit-field"
3082  Diag(Loc, diag::err_static_not_bitfield)
3083  << Name << BitWidth->getSourceRange();
3084  } else if (isa<TypedefDecl>(Member)) {
3085  // "typedef member 'x' cannot be a bit-field"
3086  Diag(Loc, diag::err_typedef_not_bitfield)
3087  << Name << BitWidth->getSourceRange();
3088  } else {
3089  // A function typedef ("typedef int f(); f a;").
3090  // C++ 9.6p3: A bit-field shall have integral or enumeration type.
3091  Diag(Loc, diag::err_not_integral_type_bitfield)
3092  << Name << cast<ValueDecl>(Member)->getType()
3093  << BitWidth->getSourceRange();
3094  }
3095 
3096  BitWidth = nullptr;
3097  Member->setInvalidDecl();
3098  }
3099 
3100  Member->setAccess(AS);
3101 
3102  // If we have declared a member function template or static data member
3103  // template, set the access of the templated declaration as well.
3104  if (FunctionTemplateDecl *FunTmpl = dyn_cast<FunctionTemplateDecl>(Member))
3105  FunTmpl->getTemplatedDecl()->setAccess(AS);
3106  else if (VarTemplateDecl *VarTmpl = dyn_cast<VarTemplateDecl>(Member))
3107  VarTmpl->getTemplatedDecl()->setAccess(AS);
3108  }
3109 
3110  if (VS.isOverrideSpecified())
3111  Member->addAttr(new (Context) OverrideAttr(VS.getOverrideLoc(), Context, 0));
3112  if (VS.isFinalSpecified())
3113  Member->addAttr(new (Context) FinalAttr(VS.getFinalLoc(), Context,
3114  VS.isFinalSpelledSealed()));
3115 
3116  if (VS.getLastLocation().isValid()) {
3117  // Update the end location of a method that has a virt-specifiers.
3118  if (CXXMethodDecl *MD = dyn_cast_or_null<CXXMethodDecl>(Member))
3119  MD->setRangeEnd(VS.getLastLocation());
3120  }
3121 
3122  CheckOverrideControl(Member);
3123 
3124  assert((Name || isInstField) && "No identifier for non-field ?");
3125 
3126  if (isInstField) {
3127  FieldDecl *FD = cast<FieldDecl>(Member);
3128  FieldCollector->Add(FD);
3129 
3130  if (!Diags.isIgnored(diag::warn_unused_private_field, FD->getLocation())) {
3131  // Remember all explicit private FieldDecls that have a name, no side
3132  // effects and are not part of a dependent type declaration.
3133  if (!FD->isImplicit() && FD->getDeclName() &&
3134  FD->getAccess() == AS_private &&
3135  !FD->hasAttr<UnusedAttr>() &&
3136  !FD->getParent()->isDependentContext() &&
3138  UnusedPrivateFields.insert(FD);
3139  }
3140  }
3141 
3142  return Member;
3143 }
3144 
3145 namespace {
3146  class UninitializedFieldVisitor
3147  : public EvaluatedExprVisitor<UninitializedFieldVisitor> {
3148  Sema &S;
3149  // List of Decls to generate a warning on. Also remove Decls that become
3150  // initialized.
3151  llvm::SmallPtrSetImpl<ValueDecl*> &Decls;
3152  // List of base classes of the record. Classes are removed after their
3153  // initializers.
3154  llvm::SmallPtrSetImpl<QualType> &BaseClasses;
3155  // Vector of decls to be removed from the Decl set prior to visiting the
3156  // nodes. These Decls may have been initialized in the prior initializer.
3157  llvm::SmallVector<ValueDecl*, 4> DeclsToRemove;
3158  // If non-null, add a note to the warning pointing back to the constructor.
3159  const CXXConstructorDecl *Constructor;
3160  // Variables to hold state when processing an initializer list. When
3161  // InitList is true, special case initialization of FieldDecls matching
3162  // InitListFieldDecl.
3163  bool InitList;
3164  FieldDecl *InitListFieldDecl;
3165  llvm::SmallVector<unsigned, 4> InitFieldIndex;
3166 
3167  public:
3169  UninitializedFieldVisitor(Sema &S,
3170  llvm::SmallPtrSetImpl<ValueDecl*> &Decls,
3171  llvm::SmallPtrSetImpl<QualType> &BaseClasses)
3172  : Inherited(S.Context), S(S), Decls(Decls), BaseClasses(BaseClasses),
3173  Constructor(nullptr), InitList(false), InitListFieldDecl(nullptr) {}
3174 
3175  // Returns true if the use of ME is not an uninitialized use.
3176  bool IsInitListMemberExprInitialized(MemberExpr *ME,
3177  bool CheckReferenceOnly) {
3179  bool ReferenceField = false;
3180  while (ME) {
3181  FieldDecl *FD = dyn_cast<FieldDecl>(ME->getMemberDecl());
3182  if (!FD)
3183  return false;
3184  Fields.push_back(FD);
3185  if (FD->getType()->isReferenceType())
3186  ReferenceField = true;
3187  ME = dyn_cast<MemberExpr>(ME->getBase()->IgnoreParenImpCasts());
3188  }
3189 
3190  // Binding a reference to an unintialized field is not an
3191  // uninitialized use.
3192  if (CheckReferenceOnly && !ReferenceField)
3193  return true;
3194 
3195  llvm::SmallVector<unsigned, 4> UsedFieldIndex;
3196  // Discard the first field since it is the field decl that is being
3197  // initialized.
3198  for (auto I = Fields.rbegin() + 1, E = Fields.rend(); I != E; ++I) {
3199  UsedFieldIndex.push_back((*I)->getFieldIndex());
3200  }
3201 
3202  for (auto UsedIter = UsedFieldIndex.begin(),
3203  UsedEnd = UsedFieldIndex.end(),
3204  OrigIter = InitFieldIndex.begin(),
3205  OrigEnd = InitFieldIndex.end();
3206  UsedIter != UsedEnd && OrigIter != OrigEnd; ++UsedIter, ++OrigIter) {
3207  if (*UsedIter < *OrigIter)
3208  return true;
3209  if (*UsedIter > *OrigIter)
3210  break;
3211  }
3212 
3213  return false;
3214  }
3215 
3216  void HandleMemberExpr(MemberExpr *ME, bool CheckReferenceOnly,
3217  bool AddressOf) {
3218  if (isa<EnumConstantDecl>(ME->getMemberDecl()))
3219  return;
3220 
3221  // FieldME is the inner-most MemberExpr that is not an anonymous struct
3222  // or union.
3223  MemberExpr *FieldME = ME;
3224 
3225  bool AllPODFields = FieldME->getType().isPODType(S.Context);
3226 
3227  Expr *Base = ME;
3228  while (MemberExpr *SubME =
3229  dyn_cast<MemberExpr>(Base->IgnoreParenImpCasts())) {
3230 
3231  if (isa<VarDecl>(SubME->getMemberDecl()))
3232  return;
3233 
3234  if (FieldDecl *FD = dyn_cast<FieldDecl>(SubME->getMemberDecl()))
3235  if (!FD->isAnonymousStructOrUnion())
3236  FieldME = SubME;
3237 
3238  if (!FieldME->getType().isPODType(S.Context))
3239  AllPODFields = false;
3240 
3241  Base = SubME->getBase();
3242  }
3243 
3244  if (!isa<CXXThisExpr>(Base->IgnoreParenImpCasts()))
3245  return;
3246 
3247  if (AddressOf && AllPODFields)
3248  return;
3249 
3250  ValueDecl* FoundVD = FieldME->getMemberDecl();
3251 
3252  if (ImplicitCastExpr *BaseCast = dyn_cast<ImplicitCastExpr>(Base)) {
3253  while (isa<ImplicitCastExpr>(BaseCast->getSubExpr())) {
3254  BaseCast = cast<ImplicitCastExpr>(BaseCast->getSubExpr());
3255  }
3256 
3257  if (BaseCast->getCastKind() == CK_UncheckedDerivedToBase) {
3258  QualType T = BaseCast->getType();
3259  if (T->isPointerType() &&
3260  BaseClasses.count(T->getPointeeType())) {
3261  S.Diag(FieldME->getExprLoc(), diag::warn_base_class_is_uninit)
3262  << T->getPointeeType() << FoundVD;
3263  }
3264  }
3265  }
3266 
3267  if (!Decls.count(FoundVD))
3268  return;
3269 
3270  const bool IsReference = FoundVD->getType()->isReferenceType();
3271 
3272  if (InitList && !AddressOf && FoundVD == InitListFieldDecl) {
3273  // Special checking for initializer lists.
3274  if (IsInitListMemberExprInitialized(ME, CheckReferenceOnly)) {
3275  return;
3276  }
3277  } else {
3278  // Prevent double warnings on use of unbounded references.
3279  if (CheckReferenceOnly && !IsReference)
3280  return;
3281  }
3282 
3283  unsigned diag = IsReference
3284  ? diag::warn_reference_field_is_uninit
3285  : diag::warn_field_is_uninit;
3286  S.Diag(FieldME->getExprLoc(), diag) << FoundVD;
3287  if (Constructor)
3288  S.Diag(Constructor->getLocation(),
3289  diag::note_uninit_in_this_constructor)
3290  << (Constructor->isDefaultConstructor() && Constructor->isImplicit());
3291 
3292  }
3293 
3294  void HandleValue(Expr *E, bool AddressOf) {
3295  E = E->IgnoreParens();
3296 
3297  if (MemberExpr *ME = dyn_cast<MemberExpr>(E)) {
3298  HandleMemberExpr(ME, false /*CheckReferenceOnly*/,
3299  AddressOf /*AddressOf*/);
3300  return;
3301  }
3302 
3303  if (ConditionalOperator *CO = dyn_cast<ConditionalOperator>(E)) {
3304  Visit(CO->getCond());
3305  HandleValue(CO->getTrueExpr(), AddressOf);
3306  HandleValue(CO->getFalseExpr(), AddressOf);
3307  return;
3308  }
3309 
3310  if (BinaryConditionalOperator *BCO =
3311  dyn_cast<BinaryConditionalOperator>(E)) {
3312  Visit(BCO->getCond());
3313  HandleValue(BCO->getFalseExpr(), AddressOf);
3314  return;
3315  }
3316 
3317  if (OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(E)) {
3318  HandleValue(OVE->getSourceExpr(), AddressOf);
3319  return;
3320  }
3321 
3322  if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) {
3323  switch (BO->getOpcode()) {
3324  default:
3325  break;
3326  case(BO_PtrMemD):
3327  case(BO_PtrMemI):
3328  HandleValue(BO->getLHS(), AddressOf);
3329  Visit(BO->getRHS());
3330  return;
3331  case(BO_Comma):
3332  Visit(BO->getLHS());
3333  HandleValue(BO->getRHS(), AddressOf);
3334  return;
3335  }
3336  }
3337 
3338  Visit(E);
3339  }
3340 
3341  void CheckInitListExpr(InitListExpr *ILE) {
3342  InitFieldIndex.push_back(0);
3343  for (auto Child : ILE->children()) {
3344  if (InitListExpr *SubList = dyn_cast<InitListExpr>(Child)) {
3345  CheckInitListExpr(SubList);
3346  } else {
3347  Visit(Child);
3348  }
3349  ++InitFieldIndex.back();
3350  }
3351  InitFieldIndex.pop_back();
3352  }
3353 
3354  void CheckInitializer(Expr *E, const CXXConstructorDecl *FieldConstructor,
3355  FieldDecl *Field, const Type *BaseClass) {
3356  // Remove Decls that may have been initialized in the previous
3357  // initializer.
3358  for (ValueDecl* VD : DeclsToRemove)
3359  Decls.erase(VD);
3360  DeclsToRemove.clear();
3361 
3362  Constructor = FieldConstructor;
3363  InitListExpr *ILE = dyn_cast<InitListExpr>(E);
3364 
3365  if (ILE && Field) {
3366  InitList = true;
3367  InitListFieldDecl = Field;
3368  InitFieldIndex.clear();
3369  CheckInitListExpr(ILE);
3370  } else {
3371  InitList = false;
3372  Visit(E);
3373  }
3374 
3375  if (Field)
3376  Decls.erase(Field);
3377  if (BaseClass)
3378  BaseClasses.erase(BaseClass->getCanonicalTypeInternal());
3379  }
3380 
3381  void VisitMemberExpr(MemberExpr *ME) {
3382  // All uses of unbounded reference fields will warn.
3383  HandleMemberExpr(ME, true /*CheckReferenceOnly*/, false /*AddressOf*/);
3384  }
3385 
3386  void VisitImplicitCastExpr(ImplicitCastExpr *E) {
3387  if (E->getCastKind() == CK_LValueToRValue) {
3388  HandleValue(E->getSubExpr(), false /*AddressOf*/);
3389  return;
3390  }
3391 
3392  Inherited::VisitImplicitCastExpr(E);
3393  }
3394 
3395  void VisitCXXConstructExpr(CXXConstructExpr *E) {
3396  if (E->getConstructor()->isCopyConstructor()) {
3397  Expr *ArgExpr = E->getArg(0);
3398  if (InitListExpr *ILE = dyn_cast<InitListExpr>(ArgExpr))
3399  if (ILE->getNumInits() == 1)
3400  ArgExpr = ILE->getInit(0);
3401  if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(ArgExpr))
3402  if (ICE->getCastKind() == CK_NoOp)
3403  ArgExpr = ICE->getSubExpr();
3404  HandleValue(ArgExpr, false /*AddressOf*/);
3405  return;
3406  }
3407  Inherited::VisitCXXConstructExpr(E);
3408  }
3409 
3410  void VisitCXXMemberCallExpr(CXXMemberCallExpr *E) {
3411  Expr *Callee = E->getCallee();
3412  if (isa<MemberExpr>(Callee)) {
3413  HandleValue(Callee, false /*AddressOf*/);
3414  for (auto Arg : E->arguments())
3415  Visit(Arg);
3416  return;
3417  }
3418 
3419  Inherited::VisitCXXMemberCallExpr(E);
3420  }
3421 
3422  void VisitCallExpr(CallExpr *E) {
3423  // Treat std::move as a use.
3424  if (E->isCallToStdMove()) {
3425  HandleValue(E->getArg(0), /*AddressOf=*/false);
3426  return;
3427  }
3428 
3429  Inherited::VisitCallExpr(E);
3430  }
3431 
3432  void VisitCXXOperatorCallExpr(CXXOperatorCallExpr *E) {
3433  Expr *Callee = E->getCallee();
3434 
3435  if (isa<UnresolvedLookupExpr>(Callee))
3436  return Inherited::VisitCXXOperatorCallExpr(E);
3437 
3438  Visit(Callee);
3439  for (auto Arg : E->arguments())
3440  HandleValue(Arg->IgnoreParenImpCasts(), false /*AddressOf*/);
3441  }
3442 
3443  void VisitBinaryOperator(BinaryOperator *E) {
3444  // If a field assignment is detected, remove the field from the
3445  // uninitiailized field set.
3446  if (E->getOpcode() == BO_Assign)
3447  if (MemberExpr *ME = dyn_cast<MemberExpr>(E->getLHS()))
3448  if (FieldDecl *FD = dyn_cast<FieldDecl>(ME->getMemberDecl()))
3449  if (!FD->getType()->isReferenceType())
3450  DeclsToRemove.push_back(FD);
3451 
3452  if (E->isCompoundAssignmentOp()) {
3453  HandleValue(E->getLHS(), false /*AddressOf*/);
3454  Visit(E->getRHS());
3455  return;
3456  }
3457 
3458  Inherited::VisitBinaryOperator(E);
3459  }
3460 
3461  void VisitUnaryOperator(UnaryOperator *E) {
3462  if (E->isIncrementDecrementOp()) {
3463  HandleValue(E->getSubExpr(), false /*AddressOf*/);
3464  return;
3465  }
3466  if (E->getOpcode() == UO_AddrOf) {
3467  if (MemberExpr *ME = dyn_cast<MemberExpr>(E->getSubExpr())) {
3468  HandleValue(ME->getBase(), true /*AddressOf*/);
3469  return;
3470  }
3471  }
3472 
3473  Inherited::VisitUnaryOperator(E);
3474  }
3475  };
3476 
3477  // Diagnose value-uses of fields to initialize themselves, e.g.
3478  // foo(foo)
3479  // where foo is not also a parameter to the constructor.
3480  // Also diagnose across field uninitialized use such as
3481  // x(y), y(x)
3482  // TODO: implement -Wuninitialized and fold this into that framework.
3483  static void DiagnoseUninitializedFields(
3484  Sema &SemaRef, const CXXConstructorDecl *Constructor) {
3485 
3486  if (SemaRef.getDiagnostics().isIgnored(diag::warn_field_is_uninit,
3487  Constructor->getLocation())) {
3488  return;
3489  }
3490 
3491  if (Constructor->isInvalidDecl())
3492  return;
3493 
3494  const CXXRecordDecl *RD = Constructor->getParent();
3495 
3496  if (RD->getDescribedClassTemplate())
3497  return;
3498 
3499  // Holds fields that are uninitialized.
3500  llvm::SmallPtrSet<ValueDecl*, 4> UninitializedFields;
3501 
3502  // At the beginning, all fields are uninitialized.
3503  for (auto *I : RD->decls()) {
3504  if (auto *FD = dyn_cast<FieldDecl>(I)) {
3505  UninitializedFields.insert(FD);
3506  } else if (auto *IFD = dyn_cast<IndirectFieldDecl>(I)) {
3507  UninitializedFields.insert(IFD->getAnonField());
3508  }
3509  }
3510 
3511  llvm::SmallPtrSet<QualType, 4> UninitializedBaseClasses;
3512  for (auto I : RD->bases())
3513  UninitializedBaseClasses.insert(I.getType().getCanonicalType());
3514 
3515  if (UninitializedFields.empty() && UninitializedBaseClasses.empty())
3516  return;
3517 
3518  UninitializedFieldVisitor UninitializedChecker(SemaRef,
3519  UninitializedFields,
3520  UninitializedBaseClasses);
3521 
3522  for (const auto *FieldInit : Constructor->inits()) {
3523  if (UninitializedFields.empty() && UninitializedBaseClasses.empty())
3524  break;
3525 
3526  Expr *InitExpr = FieldInit->getInit();
3527  if (!InitExpr)
3528  continue;
3529 
3531  dyn_cast<CXXDefaultInitExpr>(InitExpr)) {
3532  InitExpr = Default->getExpr();
3533  if (!InitExpr)
3534  continue;
3535  // In class initializers will point to the constructor.
3536  UninitializedChecker.CheckInitializer(InitExpr, Constructor,
3537  FieldInit->getAnyMember(),
3538  FieldInit->getBaseClass());
3539  } else {
3540  UninitializedChecker.CheckInitializer(InitExpr, nullptr,
3541  FieldInit->getAnyMember(),
3542  FieldInit->getBaseClass());
3543  }
3544  }
3545  }
3546 } // namespace
3547 
3548 /// \brief Enter a new C++ default initializer scope. After calling this, the
3549 /// caller must call \ref ActOnFinishCXXInClassMemberInitializer, even if
3550 /// parsing or instantiating the initializer failed.
3552  // Create a synthetic function scope to represent the call to the constructor
3553  // that notionally surrounds a use of this initializer.
3554  PushFunctionScope();
3555 }
3556 
3557 /// \brief This is invoked after parsing an in-class initializer for a
3558 /// non-static C++ class member, and after instantiating an in-class initializer
3559 /// in a class template. Such actions are deferred until the class is complete.
3561  SourceLocation InitLoc,
3562  Expr *InitExpr) {
3563  // Pop the notional constructor scope we created earlier.
3564  PopFunctionScopeInfo(nullptr, D);
3565 
3566  FieldDecl *FD = dyn_cast<FieldDecl>(D);
3567  assert((isa<MSPropertyDecl>(D) || FD->getInClassInitStyle() != ICIS_NoInit) &&
3568  "must set init style when field is created");
3569 
3570  if (!InitExpr) {
3571  D->setInvalidDecl();
3572  if (FD)
3574  return;
3575  }
3576 
3577  if (DiagnoseUnexpandedParameterPack(InitExpr, UPPC_Initializer)) {
3578  FD->setInvalidDecl();
3580  return;
3581  }
3582 
3583  ExprResult Init = InitExpr;
3584  if (!FD->getType()->isDependentType() && !InitExpr->isTypeDependent()) {
3588  : InitializationKind::CreateCopy(InitExpr->getLocStart(), InitLoc);
3589  InitializationSequence Seq(*this, Entity, Kind, InitExpr);
3590  Init = Seq.Perform(*this, Entity, Kind, InitExpr);
3591  if (Init.isInvalid()) {
3592  FD->setInvalidDecl();
3593  return;
3594  }
3595  }
3596 
3597  // C++11 [class.base.init]p7:
3598  // The initialization of each base and member constitutes a
3599  // full-expression.
3600  Init = ActOnFinishFullExpr(Init.get(), InitLoc);
3601  if (Init.isInvalid()) {
3602  FD->setInvalidDecl();
3603  return;
3604  }
3605 
3606  InitExpr = Init.get();
3607 
3608  FD->setInClassInitializer(InitExpr);
3609 }
3610 
3611 /// \brief Find the direct and/or virtual base specifiers that
3612 /// correspond to the given base type, for use in base initialization
3613 /// within a constructor.
3614 static bool FindBaseInitializer(Sema &SemaRef,
3615  CXXRecordDecl *ClassDecl,
3616  QualType BaseType,
3617  const CXXBaseSpecifier *&DirectBaseSpec,
3618  const CXXBaseSpecifier *&VirtualBaseSpec) {
3619  // First, check for a direct base class.
3620  DirectBaseSpec = nullptr;
3621  for (const auto &Base : ClassDecl->bases()) {
3622  if (SemaRef.Context.hasSameUnqualifiedType(BaseType, Base.getType())) {
3623  // We found a direct base of this type. That's what we're
3624  // initializing.
3625  DirectBaseSpec = &Base;
3626  break;
3627  }
3628  }
3629 
3630  // Check for a virtual base class.
3631  // FIXME: We might be able to short-circuit this if we know in advance that
3632  // there are no virtual bases.
3633  VirtualBaseSpec = nullptr;
3634  if (!DirectBaseSpec || !DirectBaseSpec->isVirtual()) {
3635  // We haven't found a base yet; search the class hierarchy for a
3636  // virtual base class.
3637  CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/true,
3638  /*DetectVirtual=*/false);
3639  if (SemaRef.IsDerivedFrom(ClassDecl->getLocation(),
3640  SemaRef.Context.getTypeDeclType(ClassDecl),
3641  BaseType, Paths)) {
3642  for (CXXBasePaths::paths_iterator Path = Paths.begin();
3643  Path != Paths.end(); ++Path) {
3644  if (Path->back().Base->isVirtual()) {
3645  VirtualBaseSpec = Path->back().Base;
3646  break;
3647  }
3648  }
3649  }
3650  }
3651 
3652  return DirectBaseSpec || VirtualBaseSpec;
3653 }
3654 
3655 /// \brief Handle a C++ member initializer using braced-init-list syntax.
3657 Sema::ActOnMemInitializer(Decl *ConstructorD,
3658  Scope *S,
3659  CXXScopeSpec &SS,
3660  IdentifierInfo *MemberOrBase,
3661  ParsedType TemplateTypeTy,
3662  const DeclSpec &DS,
3663  SourceLocation IdLoc,
3664  Expr *InitList,
3665  SourceLocation EllipsisLoc) {
3666  return BuildMemInitializer(ConstructorD, S, SS, MemberOrBase, TemplateTypeTy,
3667  DS, IdLoc, InitList,
3668  EllipsisLoc);
3669 }
3670 
3671 /// \brief Handle a C++ member initializer using parentheses syntax.
3673 Sema::ActOnMemInitializer(Decl *ConstructorD,
3674  Scope *S,
3675  CXXScopeSpec &SS,
3676  IdentifierInfo *MemberOrBase,
3677  ParsedType TemplateTypeTy,
3678  const DeclSpec &DS,
3679  SourceLocation IdLoc,
3680  SourceLocation LParenLoc,
3681  ArrayRef<Expr *> Args,
3682  SourceLocation RParenLoc,
3683  SourceLocation EllipsisLoc) {
3684  Expr *List = new (Context) ParenListExpr(Context, LParenLoc,
3685  Args, RParenLoc);
3686  return BuildMemInitializer(ConstructorD, S, SS, MemberOrBase, TemplateTypeTy,
3687  DS, IdLoc, List, EllipsisLoc);
3688 }
3689 
3690 namespace {
3691 
3692 // Callback to only accept typo corrections that can be a valid C++ member
3693 // intializer: either a non-static field member or a base class.
3694 class MemInitializerValidatorCCC : public CorrectionCandidateCallback {
3695 public:
3696  explicit MemInitializerValidatorCCC(CXXRecordDecl *ClassDecl)
3697  : ClassDecl(ClassDecl) {}
3698 
3699  bool ValidateCandidate(const TypoCorrection &candidate) override {
3700  if (NamedDecl *ND = candidate.getCorrectionDecl()) {
3701  if (FieldDecl *Member = dyn_cast<FieldDecl>(ND))
3702  return Member->getDeclContext()->getRedeclContext()->Equals(ClassDecl);
3703  return isa<TypeDecl>(ND);
3704  }
3705  return false;
3706  }
3707 
3708 private:
3709  CXXRecordDecl *ClassDecl;
3710 };
3711 
3712 }
3713 
3714 /// \brief Handle a C++ member initializer.
3716 Sema::BuildMemInitializer(Decl *ConstructorD,
3717  Scope *S,
3718  CXXScopeSpec &SS,
3719  IdentifierInfo *MemberOrBase,
3720  ParsedType TemplateTypeTy,
3721  const DeclSpec &DS,
3722  SourceLocation IdLoc,
3723  Expr *Init,
3724  SourceLocation EllipsisLoc) {
3725  ExprResult Res = CorrectDelayedTyposInExpr(Init);
3726  if (!Res.isUsable())
3727  return true;
3728  Init = Res.get();
3729 
3730  if (!ConstructorD)
3731  return true;
3732 
3733  AdjustDeclIfTemplate(ConstructorD);
3734 
3735  CXXConstructorDecl *Constructor
3736  = dyn_cast<CXXConstructorDecl>(ConstructorD);
3737  if (!Constructor) {
3738  // The user wrote a constructor initializer on a function that is
3739  // not a C++ constructor. Ignore the error for now, because we may
3740  // have more member initializers coming; we'll diagnose it just
3741  // once in ActOnMemInitializers.
3742  return true;
3743  }
3744 
3745  CXXRecordDecl *ClassDecl = Constructor->getParent();
3746 
3747  // C++ [class.base.init]p2:
3748  // Names in a mem-initializer-id are looked up in the scope of the
3749  // constructor's class and, if not found in that scope, are looked
3750  // up in the scope containing the constructor's definition.
3751  // [Note: if the constructor's class contains a member with the
3752  // same name as a direct or virtual base class of the class, a
3753  // mem-initializer-id naming the member or base class and composed
3754  // of a single identifier refers to the class member. A
3755  // mem-initializer-id for the hidden base class may be specified
3756  // using a qualified name. ]
3757  if (!SS.getScopeRep() && !TemplateTypeTy) {
3758  // Look for a member, first.
3759  DeclContext::lookup_result Result = ClassDecl->lookup(MemberOrBase);
3760  if (!Result.empty()) {
3761  ValueDecl *Member;
3762  if ((Member = dyn_cast<FieldDecl>(Result.front())) ||
3763  (Member = dyn_cast<IndirectFieldDecl>(Result.front()))) {
3764  if (EllipsisLoc.isValid())
3765  Diag(EllipsisLoc, diag::err_pack_expansion_member_init)
3766  << MemberOrBase
3767  << SourceRange(IdLoc, Init->getSourceRange().getEnd());
3768 
3769  return BuildMemberInitializer(Member, Init, IdLoc);
3770  }
3771  }
3772  }
3773  // It didn't name a member, so see if it names a class.
3774  QualType BaseType;
3775  TypeSourceInfo *TInfo = nullptr;
3776 
3777  if (TemplateTypeTy) {
3778  BaseType = GetTypeFromParser(TemplateTypeTy, &TInfo);
3779  } else if (DS.getTypeSpecType() == TST_decltype) {
3780  BaseType = BuildDecltypeType(DS.getRepAsExpr(), DS.getTypeSpecTypeLoc());
3781  } else if (DS.getTypeSpecType() == TST_decltype_auto) {
3782  Diag(DS.getTypeSpecTypeLoc(), diag::err_decltype_auto_invalid);
3783  return true;
3784  } else {
3785  LookupResult R(*this, MemberOrBase, IdLoc, LookupOrdinaryName);
3786  LookupParsedName(R, S, &SS);
3787 
3788  TypeDecl *TyD = R.getAsSingle<TypeDecl>();
3789  if (!TyD) {
3790  if (R.isAmbiguous()) return true;
3791 
3792  // We don't want access-control diagnostics here.
3793  R.suppressDiagnostics();
3794 
3795  if (SS.isSet() && isDependentScopeSpecifier(SS)) {
3796  bool NotUnknownSpecialization = false;
3797  DeclContext *DC = computeDeclContext(SS, false);
3798  if (CXXRecordDecl *Record = dyn_cast_or_null<CXXRecordDecl>(DC))
3799  NotUnknownSpecialization = !Record->hasAnyDependentBases();
3800 
3801  if (!NotUnknownSpecialization) {
3802  // When the scope specifier can refer to a member of an unknown
3803  // specialization, we take it as a type name.
3804  BaseType = CheckTypenameType(ETK_None, SourceLocation(),
3805  SS.getWithLocInContext(Context),
3806  *MemberOrBase, IdLoc);
3807  if (BaseType.isNull())
3808  return true;
3809 
3810  TInfo = Context.CreateTypeSourceInfo(BaseType);
3813  if (!TL.isNull()) {
3814  TL.setNameLoc(IdLoc);
3816  TL.setQualifierLoc(SS.getWithLocInContext(Context));
3817  }
3818 
3819  R.clear();
3820  R.setLookupName(MemberOrBase);
3821  }
3822  }
3823 
3824  // If no results were found, try to correct typos.
3825  TypoCorrection Corr;
3826  if (R.empty() && BaseType.isNull() &&
3827  (Corr = CorrectTypo(
3828  R.getLookupNameInfo(), R.getLookupKind(), S, &SS,
3829  llvm::make_unique<MemInitializerValidatorCCC>(ClassDecl),
3830  CTK_ErrorRecovery, ClassDecl))) {
3831  if (FieldDecl *Member = Corr.getCorrectionDeclAs<FieldDecl>()) {
3832  // We have found a non-static data member with a similar
3833  // name to what was typed; complain and initialize that
3834  // member.
3835  diagnoseTypo(Corr,
3836  PDiag(diag::err_mem_init_not_member_or_class_suggest)
3837  << MemberOrBase << true);
3838  return BuildMemberInitializer(Member, Init, IdLoc);
3839  } else if (TypeDecl *Type = Corr.getCorrectionDeclAs<TypeDecl>()) {
3840  const CXXBaseSpecifier *DirectBaseSpec;
3841  const CXXBaseSpecifier *VirtualBaseSpec;
3842  if (FindBaseInitializer(*this, ClassDecl,
3843  Context.getTypeDeclType(Type),
3844  DirectBaseSpec, VirtualBaseSpec)) {
3845  // We have found a direct or virtual base class with a
3846  // similar name to what was typed; complain and initialize
3847  // that base class.
3848  diagnoseTypo(Corr,
3849  PDiag(diag::err_mem_init_not_member_or_class_suggest)
3850  << MemberOrBase << false,
3851  PDiag() /*Suppress note, we provide our own.*/);
3852 
3853  const CXXBaseSpecifier *BaseSpec = DirectBaseSpec ? DirectBaseSpec
3854  : VirtualBaseSpec;
3855  Diag(BaseSpec->getLocStart(),
3856  diag::note_base_class_specified_here)
3857  << BaseSpec->getType()
3858  << BaseSpec->getSourceRange();
3859 
3860  TyD = Type;
3861  }
3862  }
3863  }
3864 
3865  if (!TyD && BaseType.isNull()) {
3866  Diag(IdLoc, diag::err_mem_init_not_member_or_class)
3867  << MemberOrBase << SourceRange(IdLoc,Init->getSourceRange().getEnd());
3868  return true;
3869  }
3870  }
3871 
3872  if (BaseType.isNull()) {
3873  BaseType = Context.getTypeDeclType(TyD);
3874  MarkAnyDeclReferenced(TyD->getLocation(), TyD, /*OdrUse=*/false);
3875  if (SS.isSet()) {
3876  BaseType = Context.getElaboratedType(ETK_None, SS.getScopeRep(),
3877  BaseType);
3878  TInfo = Context.CreateTypeSourceInfo(BaseType);
3880  TL.getNamedTypeLoc().castAs<TypeSpecTypeLoc>().setNameLoc(IdLoc);
3882  TL.setQualifierLoc(SS.getWithLocInContext(Context));
3883  }
3884  }
3885  }
3886 
3887  if (!TInfo)
3888  TInfo = Context.getTrivialTypeSourceInfo(BaseType, IdLoc);
3889 
3890  return BuildBaseInitializer(BaseType, TInfo, Init, ClassDecl, EllipsisLoc);
3891 }
3892 
3893 /// Checks a member initializer expression for cases where reference (or
3894 /// pointer) members are bound to by-value parameters (or their addresses).
3896  Expr *Init,
3897  SourceLocation IdLoc) {
3898  QualType MemberTy = Member->getType();
3899 
3900  // We only handle pointers and references currently.
3901  // FIXME: Would this be relevant for ObjC object pointers? Or block pointers?
3902  if (!MemberTy->isReferenceType() && !MemberTy->isPointerType())
3903  return;
3904 
3905  const bool IsPointer = MemberTy->isPointerType();
3906  if (IsPointer) {
3907  if (const UnaryOperator *Op
3908  = dyn_cast<UnaryOperator>(Init->IgnoreParenImpCasts())) {
3909  // The only case we're worried about with pointers requires taking the
3910  // address.
3911  if (Op->getOpcode() != UO_AddrOf)
3912  return;
3913 
3914  Init = Op->getSubExpr();
3915  } else {
3916  // We only handle address-of expression initializers for pointers.
3917  return;
3918  }
3919  }
3920 
3921  if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Init->IgnoreParens())) {
3922  // We only warn when referring to a non-reference parameter declaration.
3923  const ParmVarDecl *Parameter = dyn_cast<ParmVarDecl>(DRE->getDecl());
3924  if (!Parameter || Parameter->getType()->isReferenceType())
3925  return;
3926 
3927  S.Diag(Init->getExprLoc(),
3928  IsPointer ? diag::warn_init_ptr_member_to_parameter_addr
3929  : diag::warn_bind_ref_member_to_parameter)
3930  << Member << Parameter << Init->getSourceRange();
3931  } else {
3932  // Other initializers are fine.
3933  return;
3934  }
3935 
3936  S.Diag(Member->getLocation(), diag::note_ref_or_ptr_member_declared_here)
3937  << (unsigned)IsPointer;
3938 }
3939 
3942  SourceLocation IdLoc) {
3943  FieldDecl *DirectMember = dyn_cast<FieldDecl>(Member);
3944  IndirectFieldDecl *IndirectMember = dyn_cast<IndirectFieldDecl>(Member);
3945  assert((DirectMember || IndirectMember) &&
3946  "Member must be a FieldDecl or IndirectFieldDecl");
3947 
3948  if (DiagnoseUnexpandedParameterPack(Init, UPPC_Initializer))
3949  return true;
3950 
3951  if (Member->isInvalidDecl())
3952  return true;
3953 
3954  MultiExprArg Args;
3955  if (ParenListExpr *ParenList = dyn_cast<ParenListExpr>(Init)) {
3956  Args = MultiExprArg(ParenList->getExprs(), ParenList->getNumExprs());
3957  } else if (InitListExpr *InitList = dyn_cast<InitListExpr>(Init)) {
3958  Args = MultiExprArg(InitList->getInits(), InitList->getNumInits());
3959  } else {
3960  // Template instantiation doesn't reconstruct ParenListExprs for us.
3961  Args = Init;
3962  }
3963 
3964  SourceRange InitRange = Init->getSourceRange();
3965 
3966  if (Member->getType()->isDependentType() || Init->isTypeDependent()) {
3967  // Can't check initialization for a member of dependent type or when
3968  // any of the arguments are type-dependent expressions.
3969  DiscardCleanupsInEvaluationContext();
3970  } else {
3971  bool InitList = false;
3972  if (isa<InitListExpr>(Init)) {
3973  InitList = true;
3974  Args = Init;
3975  }
3976 
3977  // Initialize the member.
3978  InitializedEntity MemberEntity =
3979  DirectMember ? InitializedEntity::InitializeMember(DirectMember, nullptr)
3980  : InitializedEntity::InitializeMember(IndirectMember,
3981  nullptr);
3983  InitList ? InitializationKind::CreateDirectList(IdLoc)
3984  : InitializationKind::CreateDirect(IdLoc, InitRange.getBegin(),
3985  InitRange.getEnd());
3986 
3987  InitializationSequence InitSeq(*this, MemberEntity, Kind, Args);
3988  ExprResult MemberInit = InitSeq.Perform(*this, MemberEntity, Kind, Args,
3989  nullptr);
3990  if (MemberInit.isInvalid())
3991  return true;
3992 
3993  CheckForDanglingReferenceOrPointer(*this, Member, MemberInit.get(), IdLoc);
3994 
3995  // C++11 [class.base.init]p7:
3996  // The initialization of each base and member constitutes a
3997  // full-expression.
3998  MemberInit = ActOnFinishFullExpr(MemberInit.get(), InitRange.getBegin());
3999  if (MemberInit.isInvalid())
4000  return true;
4001 
4002  Init = MemberInit.get();
4003  }
4004 
4005  if (DirectMember) {
4006  return new (Context) CXXCtorInitializer(Context, DirectMember, IdLoc,
4007  InitRange.getBegin(), Init,
4008  InitRange.getEnd());
4009  } else {
4010  return new (Context) CXXCtorInitializer(Context, IndirectMember, IdLoc,
4011  InitRange.getBegin(), Init,
4012  InitRange.getEnd());
4013  }
4014 }
4015 
4018  CXXRecordDecl *ClassDecl) {
4019  SourceLocation NameLoc = TInfo->getTypeLoc().getLocalSourceRange().getBegin();
4020  if (!LangOpts.CPlusPlus11)
4021  return Diag(NameLoc, diag::err_delegating_ctor)
4022  << TInfo->getTypeLoc().getLocalSourceRange();
4023  Diag(NameLoc, diag::warn_cxx98_compat_delegating_ctor);
4024 
4025  bool InitList = true;
4026  MultiExprArg Args = Init;
4027  if (ParenListExpr *ParenList = dyn_cast<ParenListExpr>(Init)) {
4028  InitList = false;
4029  Args = MultiExprArg(ParenList->getExprs(), ParenList->getNumExprs());
4030  }
4031 
4032  SourceRange InitRange = Init->getSourceRange();
4033  // Initialize the object.
4035  QualType(ClassDecl->getTypeForDecl(), 0));
4037  InitList ? InitializationKind::CreateDirectList(NameLoc)
4038  : InitializationKind::CreateDirect(NameLoc, InitRange.getBegin(),
4039  InitRange.getEnd());
4040  InitializationSequence InitSeq(*this, DelegationEntity, Kind, Args);
4041  ExprResult DelegationInit = InitSeq.Perform(*this, DelegationEntity, Kind,
4042  Args, nullptr);
4043  if (DelegationInit.isInvalid())
4044  return true;
4045 
4046  assert(cast<CXXConstructExpr>(DelegationInit.get())->getConstructor() &&
4047  "Delegating constructor with no target?");
4048 
4049  // C++11 [class.base.init]p7:
4050  // The initialization of each base and member constitutes a
4051  // full-expression.
4052  DelegationInit = ActOnFinishFullExpr(DelegationInit.get(),
4053  InitRange.getBegin());
4054  if (DelegationInit.isInvalid())
4055  return true;
4056 
4057  // If we are in a dependent context, template instantiation will
4058  // perform this type-checking again. Just save the arguments that we
4059  // received in a ParenListExpr.
4060  // FIXME: This isn't quite ideal, since our ASTs don't capture all
4061  // of the information that we have about the base
4062  // initializer. However, deconstructing the ASTs is a dicey process,
4063  // and this approach is far more likely to get the corner cases right.
4064  if (CurContext->isDependentContext())
4065  DelegationInit = Init;
4066 
4067  return new (Context) CXXCtorInitializer(Context, TInfo, InitRange.getBegin(),
4068  DelegationInit.getAs<Expr>(),
4069  InitRange.getEnd());
4070 }
4071 
4074  Expr *Init, CXXRecordDecl *ClassDecl,
4075  SourceLocation EllipsisLoc) {
4076  SourceLocation BaseLoc
4077  = BaseTInfo->getTypeLoc().getLocalSourceRange().getBegin();
4078 
4079  if (!BaseType->isDependentType() && !BaseType->isRecordType())
4080  return Diag(BaseLoc, diag::err_base_init_does_not_name_class)
4081  << BaseType << BaseTInfo->getTypeLoc().getLocalSourceRange();
4082 
4083  // C++ [class.base.init]p2:
4084  // [...] Unless the mem-initializer-id names a nonstatic data
4085  // member of the constructor's class or a direct or virtual base
4086  // of that class, the mem-initializer is ill-formed. A
4087  // mem-initializer-list can initialize a base class using any
4088  // name that denotes that base class type.
4089  bool Dependent = BaseType->isDependentType() || Init->isTypeDependent();
4090 
4091  SourceRange InitRange = Init->getSourceRange();
4092  if (EllipsisLoc.isValid()) {
4093  // This is a pack expansion.
4094  if (!BaseType->containsUnexpandedParameterPack()) {
4095  Diag(EllipsisLoc, diag::err_pack_expansion_without_parameter_packs)
4096  << SourceRange(BaseLoc, InitRange.getEnd());
4097 
4098  EllipsisLoc = SourceLocation();
4099  }
4100  } else {
4101  // Check for any unexpanded parameter packs.
4102  if (DiagnoseUnexpandedParameterPack(BaseLoc, BaseTInfo, UPPC_Initializer))
4103  return true;
4104 
4105  if (DiagnoseUnexpandedParameterPack(Init, UPPC_Initializer))
4106  return true;
4107  }
4108 
4109  // Check for direct and virtual base classes.
4110  const CXXBaseSpecifier *DirectBaseSpec = nullptr;
4111  const CXXBaseSpecifier *VirtualBaseSpec = nullptr;
4112  if (!Dependent) {
4113  if (Context.hasSameUnqualifiedType(QualType(ClassDecl->getTypeForDecl(),0),
4114  BaseType))
4115  return BuildDelegatingInitializer(BaseTInfo, Init, ClassDecl);
4116 
4117  FindBaseInitializer(*this, ClassDecl, BaseType, DirectBaseSpec,
4118  VirtualBaseSpec);
4119 
4120  // C++ [base.class.init]p2:
4121  // Unless the mem-initializer-id names a nonstatic data member of the
4122  // constructor's class or a direct or virtual base of that class, the
4123  // mem-initializer is ill-formed.
4124  if (!DirectBaseSpec && !VirtualBaseSpec) {
4125  // If the class has any dependent bases, then it's possible that
4126  // one of those types will resolve to the same type as
4127  // BaseType. Therefore, just treat this as a dependent base
4128  // class initialization. FIXME: Should we try to check the
4129  // initialization anyway? It seems odd.
4130  if (ClassDecl->hasAnyDependentBases())
4131  Dependent = true;
4132  else
4133  return Diag(BaseLoc, diag::err_not_direct_base_or_virtual)
4134  << BaseType << Context.getTypeDeclType(ClassDecl)
4135  << BaseTInfo->getTypeLoc().getLocalSourceRange();
4136  }
4137  }
4138 
4139  if (Dependent) {
4140  DiscardCleanupsInEvaluationContext();
4141 
4142  return new (Context) CXXCtorInitializer(Context, BaseTInfo,
4143  /*IsVirtual=*/false,
4144  InitRange.getBegin(), Init,
4145  InitRange.getEnd(), EllipsisLoc);
4146  }
4147 
4148  // C++ [base.class.init]p2:
4149  // If a mem-initializer-id is ambiguous because it designates both
4150  // a direct non-virtual base class and an inherited virtual base
4151  // class, the mem-initializer is ill-formed.
4152  if (DirectBaseSpec && VirtualBaseSpec)
4153  return Diag(BaseLoc, diag::err_base_init_direct_and_virtual)
4154  << BaseType << BaseTInfo->getTypeLoc().getLocalSourceRange();
4155 
4156  const CXXBaseSpecifier *BaseSpec = DirectBaseSpec;
4157  if (!BaseSpec)
4158  BaseSpec = VirtualBaseSpec;
4159 
4160  // Initialize the base.
4161  bool InitList = true;
4162  MultiExprArg Args = Init;
4163  if (ParenListExpr *ParenList = dyn_cast<ParenListExpr>(Init)) {
4164  InitList = false;
4165  Args = MultiExprArg(ParenList->getExprs(), ParenList->getNumExprs());
4166  }
4167 
4168  InitializedEntity BaseEntity =
4169  InitializedEntity::InitializeBase(Context, BaseSpec, VirtualBaseSpec);
4171  InitList ? InitializationKind::CreateDirectList(BaseLoc)
4172  : InitializationKind::CreateDirect(BaseLoc, InitRange.getBegin(),
4173  InitRange.getEnd());
4174  InitializationSequence InitSeq(*this, BaseEntity, Kind, Args);
4175  ExprResult BaseInit = InitSeq.Perform(*this, BaseEntity, Kind, Args, nullptr);
4176  if (BaseInit.isInvalid())
4177  return true;
4178 
4179  // C++11 [class.base.init]p7:
4180  // The initialization of each base and member constitutes a
4181  // full-expression.
4182  BaseInit = ActOnFinishFullExpr(BaseInit.get(), InitRange.getBegin());
4183  if (BaseInit.isInvalid())
4184  return true;
4185 
4186  // If we are in a dependent context, template instantiation will
4187  // perform this type-checking again. Just save the arguments that we
4188  // received in a ParenListExpr.
4189  // FIXME: This isn't quite ideal, since our ASTs don't capture all
4190  // of the information that we have about the base
4191  // initializer. However, deconstructing the ASTs is a dicey process,
4192  // and this approach is far more likely to get the corner cases right.
4193  if (CurContext->isDependentContext())
4194  BaseInit = Init;
4195 
4196  return new (Context) CXXCtorInitializer(Context, BaseTInfo,
4197  BaseSpec->isVirtual(),
4198  InitRange.getBegin(),
4199  BaseInit.getAs<Expr>(),
4200  InitRange.getEnd(), EllipsisLoc);
4201 }
4202 
4203 // Create a static_cast<T&&>(expr).
4204 static Expr *CastForMoving(Sema &SemaRef, Expr *E, QualType T = QualType()) {
4205  if (T.isNull()) T = E->getType();
4206  QualType TargetType = SemaRef.BuildReferenceType(
4207  T, /*SpelledAsLValue*/false, SourceLocation(), DeclarationName());
4208  SourceLocation ExprLoc = E->getLocStart();
4209  TypeSourceInfo *TargetLoc = SemaRef.Context.getTrivialTypeSourceInfo(
4210  TargetType, ExprLoc);
4211 
4212  return SemaRef.BuildCXXNamedCast(ExprLoc, tok::kw_static_cast, TargetLoc, E,
4213  SourceRange(ExprLoc, ExprLoc),
4214  E->getSourceRange()).get();
4215 }
4216 
4217 /// ImplicitInitializerKind - How an implicit base or member initializer should
4218 /// initialize its base or member.
4224 };
4225 
4226 static bool
4228  ImplicitInitializerKind ImplicitInitKind,
4229  CXXBaseSpecifier *BaseSpec,
4230  bool IsInheritedVirtualBase,
4231  CXXCtorInitializer *&CXXBaseInit) {
4232  InitializedEntity InitEntity
4233  = InitializedEntity::InitializeBase(SemaRef.Context, BaseSpec,
4234  IsInheritedVirtualBase);
4235 
4236  ExprResult BaseInit;
4237 
4238  switch (ImplicitInitKind) {
4239  case IIK_Inherit:
4240  case IIK_Default: {
4241  InitializationKind InitKind
4243  InitializationSequence InitSeq(SemaRef, InitEntity, InitKind, None);
4244  BaseInit = InitSeq.Perform(SemaRef, InitEntity, InitKind, None);
4245  break;
4246  }
4247 
4248  case IIK_Move:
4249  case IIK_Copy: {
4250  bool Moving = ImplicitInitKind == IIK_Move;
4251  ParmVarDecl *Param = Constructor->getParamDecl(0);
4252  QualType ParamType = Param->getType().getNonReferenceType();
4253 
4254  Expr *CopyCtorArg =
4256  SourceLocation(), Param, false,
4257  Constructor->getLocation(), ParamType,
4258  VK_LValue, nullptr);
4259 
4260  SemaRef.MarkDeclRefReferenced(cast<DeclRefExpr>(CopyCtorArg));
4261 
4262  // Cast to the base class to avoid ambiguities.
4263  QualType ArgTy =
4264  SemaRef.Context.getQualifiedType(BaseSpec->getType().getUnqualifiedType(),
4265  ParamType.getQualifiers());
4266 
4267  if (Moving) {
4268  CopyCtorArg = CastForMoving(SemaRef, CopyCtorArg);
4269  }
4270 
4271  CXXCastPath BasePath;
4272  BasePath.push_back(BaseSpec);
4273  CopyCtorArg = SemaRef.ImpCastExprToType(CopyCtorArg, ArgTy,
4274  CK_UncheckedDerivedToBase,
4275  Moving ? VK_XValue : VK_LValue,
4276  &BasePath).get();
4277 
4278  InitializationKind InitKind
4281  InitializationSequence InitSeq(SemaRef, InitEntity, InitKind, CopyCtorArg);
4282  BaseInit = InitSeq.Perform(SemaRef, InitEntity, InitKind, CopyCtorArg);
4283  break;
4284  }
4285  }
4286 
4287  BaseInit = SemaRef.MaybeCreateExprWithCleanups(BaseInit);
4288  if (BaseInit.isInvalid())
4289  return true;
4290 
4291  CXXBaseInit =
4292  new (SemaRef.Context) CXXCtorInitializer(SemaRef.Context,
4293  SemaRef.Context.getTrivialTypeSourceInfo(BaseSpec->getType(),
4294  SourceLocation()),
4295  BaseSpec->isVirtual(),
4296  SourceLocation(),
4297  BaseInit.getAs<Expr>(),
4298  SourceLocation(),
4299  SourceLocation());
4300 
4301  return false;
4302 }
4303 
4304 static bool RefersToRValueRef(Expr *MemRef) {
4305  ValueDecl *Referenced = cast<MemberExpr>(MemRef)->getMemberDecl();
4306  return Referenced->getType()->isRValueReferenceType();
4307 }
4308 
4309 static bool
4311  ImplicitInitializerKind ImplicitInitKind,
4312  FieldDecl *Field, IndirectFieldDecl *Indirect,
4313  CXXCtorInitializer *&CXXMemberInit) {
4314  if (Field->isInvalidDecl())
4315  return true;
4316 
4317  SourceLocation Loc = Constructor->getLocation();
4318 
4319  if (ImplicitInitKind == IIK_Copy || ImplicitInitKind == IIK_Move) {
4320  bool Moving = ImplicitInitKind == IIK_Move;
4321  ParmVarDecl *Param = Constructor->getParamDecl(0);
4322  QualType ParamType = Param->getType().getNonReferenceType();
4323 
4324  // Suppress copying zero-width bitfields.
4325  if (Field->isBitField() && Field->getBitWidthValue(SemaRef.Context) == 0)
4326  return false;
4327 
4328  Expr *MemberExprBase =
4330  SourceLocation(), Param, false,
4331  Loc, ParamType, VK_LValue, nullptr);
4332 
4333  SemaRef.MarkDeclRefReferenced(cast<DeclRefExpr>(MemberExprBase));
4334 
4335  if (Moving) {
4336  MemberExprBase = CastForMoving(SemaRef, MemberExprBase);
4337  }
4338 
4339  // Build a reference to this field within the parameter.
4340  CXXScopeSpec SS;
4341  LookupResult MemberLookup(SemaRef, Field->getDeclName(), Loc,
4343  MemberLookup.addDecl(Indirect ? cast<ValueDecl>(Indirect)
4344  : cast<ValueDecl>(Field), AS_public);
4345  MemberLookup.resolveKind();
4346  ExprResult CtorArg
4347  = SemaRef.BuildMemberReferenceExpr(MemberExprBase,
4348  ParamType, Loc,
4349  /*IsArrow=*/false,
4350  SS,
4351  /*TemplateKWLoc=*/SourceLocation(),
4352  /*FirstQualifierInScope=*/nullptr,
4353  MemberLookup,
4354  /*TemplateArgs=*/nullptr,
4355  /*S*/nullptr);
4356  if (CtorArg.isInvalid())
4357  return true;
4358 
4359  // C++11 [class.copy]p15:
4360  // - if a member m has rvalue reference type T&&, it is direct-initialized
4361  // with static_cast<T&&>(x.m);
4362  if (RefersToRValueRef(CtorArg.get())) {
4363  CtorArg = CastForMoving(SemaRef, CtorArg.get());
4364  }
4365 
4366  InitializedEntity Entity =
4367  Indirect ? InitializedEntity::InitializeMember(Indirect, nullptr,
4368  /*Implicit*/ true)
4369  : InitializedEntity::InitializeMember(Field, nullptr,
4370  /*Implicit*/ true);
4371 
4372  // Direct-initialize to use the copy constructor.
4373  InitializationKind InitKind =
4375 
4376  Expr *CtorArgE = CtorArg.getAs<Expr>();
4377  InitializationSequence InitSeq(SemaRef, Entity, InitKind, CtorArgE);
4378  ExprResult MemberInit =
4379  InitSeq.Perform(SemaRef, Entity, InitKind, MultiExprArg(&CtorArgE, 1));
4380  MemberInit = SemaRef.MaybeCreateExprWithCleanups(MemberInit);
4381  if (MemberInit.isInvalid())
4382  return true;
4383 
4384  if (Indirect)
4385  CXXMemberInit = new (SemaRef.Context) CXXCtorInitializer(
4386  SemaRef.Context, Indirect, Loc, Loc, MemberInit.getAs<Expr>(), Loc);
4387  else
4388  CXXMemberInit = new (SemaRef.Context) CXXCtorInitializer(
4389  SemaRef.Context, Field, Loc, Loc, MemberInit.getAs<Expr>(), Loc);
4390  return false;
4391  }
4392 
4393  assert((ImplicitInitKind == IIK_Default || ImplicitInitKind == IIK_Inherit) &&
4394  "Unhandled implicit init kind!");
4395 
4396  QualType FieldBaseElementType =
4397  SemaRef.Context.getBaseElementType(Field->getType());
4398 
4399  if (FieldBaseElementType->isRecordType()) {
4400  InitializedEntity InitEntity =
4401  Indirect ? InitializedEntity::InitializeMember(Indirect, nullptr,
4402  /*Implicit*/ true)
4403  : InitializedEntity::InitializeMember(Field, nullptr,
4404  /*Implicit*/ true);
4405  InitializationKind InitKind =
4407 
4408  InitializationSequence InitSeq(SemaRef, InitEntity, InitKind, None);
4409  ExprResult MemberInit =
4410  InitSeq.Perform(SemaRef, InitEntity, InitKind, None);
4411 
4412  MemberInit = SemaRef.MaybeCreateExprWithCleanups(MemberInit);
4413  if (MemberInit.isInvalid())
4414  return true;
4415 
4416  if (Indirect)
4417  CXXMemberInit = new (SemaRef.Context) CXXCtorInitializer(SemaRef.Context,
4418  Indirect, Loc,
4419  Loc,
4420  MemberInit.get(),
4421  Loc);
4422  else
4423  CXXMemberInit = new (SemaRef.Context) CXXCtorInitializer(SemaRef.Context,
4424  Field, Loc, Loc,
4425  MemberInit.get(),
4426  Loc);
4427  return false;
4428  }
4429 
4430  if (!Field->getParent()->isUnion()) {
4431  if (FieldBaseElementType->isReferenceType()) {
4432  SemaRef.Diag(Constructor->getLocation(),
4433  diag::err_uninitialized_member_in_ctor)
4434  << (int)Constructor->isImplicit()
4435  << SemaRef.Context.getTagDeclType(Constructor->getParent())
4436  << 0 << Field->getDeclName();
4437  SemaRef.Diag(Field->getLocation(), diag::note_declared_at);
4438  return true;
4439  }
4440 
4441  if (FieldBaseElementType.isConstQualified()) {
4442  SemaRef.Diag(Constructor->getLocation(),
4443  diag::err_uninitialized_member_in_ctor)
4444  << (int)Constructor->isImplicit()
4445  << SemaRef.Context.getTagDeclType(Constructor->getParent())
4446  << 1 << Field->getDeclName();
4447  SemaRef.Diag(Field->getLocation(), diag::note_declared_at);
4448  return true;
4449  }
4450  }
4451 
4452  if (FieldBaseElementType.hasNonTrivialObjCLifetime()) {
4453  // ARC and Weak:
4454  // Default-initialize Objective-C pointers to NULL.
4455  CXXMemberInit
4456  = new (SemaRef.Context) CXXCtorInitializer(SemaRef.Context, Field,
4457  Loc, Loc,
4458  new (SemaRef.Context) ImplicitValueInitExpr(Field->getType()),
4459  Loc);
4460  return false;
4461  }
4462 
4463  // Nothing to initialize.
4464  CXXMemberInit = nullptr;
4465  return false;
4466 }
4467 
4468 namespace {
4469 struct BaseAndFieldInfo {
4470  Sema &S;
4471  CXXConstructorDecl *Ctor;
4472  bool AnyErrorsInInits;
4474  llvm::DenseMap<const void *, CXXCtorInitializer*> AllBaseFields;
4476  llvm::DenseMap<TagDecl*, FieldDecl*> ActiveUnionMember;
4477 
4478  BaseAndFieldInfo(Sema &S, CXXConstructorDecl *Ctor, bool ErrorsInInits)
4479  : S(S), Ctor(Ctor), AnyErrorsInInits(ErrorsInInits) {
4480  bool Generated = Ctor->isImplicit() || Ctor->isDefaulted();
4481  if (Ctor->getInheritedConstructor())
4482  IIK = IIK_Inherit;
4483  else if (Generated && Ctor->isCopyConstructor())
4484  IIK = IIK_Copy;
4485  else if (Generated && Ctor->isMoveConstructor())
4486  IIK = IIK_Move;
4487  else
4488  IIK = IIK_Default;
4489  }
4490 
4491  bool isImplicitCopyOrMove() const {
4492  switch (IIK) {
4493  case IIK_Copy:
4494  case IIK_Move:
4495  return true;
4496 
4497  case IIK_Default:
4498  case IIK_Inherit:
4499  return false;
4500  }
4501 
4502  llvm_unreachable("Invalid ImplicitInitializerKind!");
4503  }
4504 
4505  bool addFieldInitializer(CXXCtorInitializer *Init) {
4506  AllToInit.push_back(Init);
4507 
4508  // Check whether this initializer makes the field "used".
4509  if (Init->getInit()->HasSideEffects(S.Context))
4510  S.UnusedPrivateFields.remove(Init->getAnyMember());
4511 
4512  return false;
4513  }
4514 
4515  bool isInactiveUnionMember(FieldDecl *Field) {
4516  RecordDecl *Record = Field->getParent();
4517  if (!Record->isUnion())
4518  return false;
4519 
4520  if (FieldDecl *Active =
4521  ActiveUnionMember.lookup(Record->getCanonicalDecl()))
4522  return Active != Field->getCanonicalDecl();
4523 
4524  // In an implicit copy or move constructor, ignore any in-class initializer.
4525  if (isImplicitCopyOrMove())
4526  return true;
4527 
4528  // If there's no explicit initialization, the field is active only if it
4529  // has an in-class initializer...
4530  if (Field->hasInClassInitializer())
4531  return false;
4532  // ... or it's an anonymous struct or union whose class has an in-class
4533  // initializer.
4534  if (!Field->isAnonymousStructOrUnion())
4535  return true;
4536  CXXRecordDecl *FieldRD = Field->getType()->getAsCXXRecordDecl();
4537  return !FieldRD->hasInClassInitializer();
4538  }
4539 
4540  /// \brief Determine whether the given field is, or is within, a union member
4541  /// that is inactive (because there was an initializer given for a different
4542  /// member of the union, or because the union was not initialized at all).
4543  bool isWithinInactiveUnionMember(FieldDecl *Field,
4544  IndirectFieldDecl *Indirect) {
4545  if (!Indirect)
4546  return isInactiveUnionMember(Field);
4547 
4548  for (auto *C : Indirect->chain()) {
4549  FieldDecl *Field = dyn_cast<FieldDecl>(C);
4550  if (Field && isInactiveUnionMember(Field))
4551  return true;
4552  }
4553  return false;
4554  }
4555 };
4556 }
4557 
4558 /// \brief Determine whether the given type is an incomplete or zero-lenfgth
4559 /// array type.
4561  if (T->isIncompleteArrayType())
4562  return true;
4563 
4564  while (const ConstantArrayType *ArrayT = Context.getAsConstantArrayType(T)) {
4565  if (!ArrayT->getSize())
4566  return true;
4567 
4568  T = ArrayT->getElementType();
4569  }
4570 
4571  return false;
4572 }
4573 
4574 static bool CollectFieldInitializer(Sema &SemaRef, BaseAndFieldInfo &Info,
4575  FieldDecl *Field,
4576  IndirectFieldDecl *Indirect = nullptr) {
4577  if (Field->isInvalidDecl())
4578  return false;
4579 
4580  // Overwhelmingly common case: we have a direct initializer for this field.
4581  if (CXXCtorInitializer *Init =
4582  Info.AllBaseFields.lookup(Field->getCanonicalDecl()))
4583  return Info.addFieldInitializer(Init);
4584 
4585  // C++11 [class.base.init]p8:
4586  // if the entity is a non-static data member that has a
4587  // brace-or-equal-initializer and either
4588  // -- the constructor's class is a union and no other variant member of that
4589  // union is designated by a mem-initializer-id or
4590  // -- the constructor's class is not a union, and, if the entity is a member
4591  // of an anonymous union, no other member of that union is designated by
4592  // a mem-initializer-id,
4593  // the entity is initialized as specified in [dcl.init].
4594  //
4595  // We also apply the same rules to handle anonymous structs within anonymous
4596  // unions.
4597  if (Info.isWithinInactiveUnionMember(Field, Indirect))
4598  return false;
4599 
4600  if (Field->hasInClassInitializer() && !Info.isImplicitCopyOrMove()) {
4601  ExprResult DIE =
4602  SemaRef.BuildCXXDefaultInitExpr(Info.Ctor->getLocation(), Field);
4603  if (DIE.isInvalid())
4604  return true;
4605  CXXCtorInitializer *Init;
4606  if (Indirect)
4607  Init = new (SemaRef.Context)
4608  CXXCtorInitializer(SemaRef.Context, Indirect, SourceLocation(),
4609  SourceLocation(), DIE.get(), SourceLocation());
4610  else
4611  Init = new (SemaRef.Context)
4612  CXXCtorInitializer(SemaRef.Context, Field, SourceLocation(),
4613  SourceLocation(), DIE.get(), SourceLocation());
4614  return Info.addFieldInitializer(Init);
4615  }
4616 
4617  // Don't initialize incomplete or zero-length arrays.
4618  if (isIncompleteOrZeroLengthArrayType(SemaRef.Context, Field->getType()))
4619  return false;
4620 
4621  // Don't try to build an implicit initializer if there were semantic
4622  // errors in any of the initializers (and therefore we might be
4623  // missing some that the user actually wrote).
4624  if (Info.AnyErrorsInInits)
4625  return false;
4626 
4627  CXXCtorInitializer *Init = nullptr;
4628  if (BuildImplicitMemberInitializer(Info.S, Info.Ctor, Info.IIK, Field,
4629  Indirect, Init))
4630  return true;
4631 
4632  if (!Init)
4633  return false;
4634 
4635  return Info.addFieldInitializer(Init);
4636 }
4637 
4638 bool
4640  CXXCtorInitializer *Initializer) {
4641  assert(Initializer->isDelegatingInitializer());
4642  Constructor->setNumCtorInitializers(1);
4643  CXXCtorInitializer **initializer =
4644  new (Context) CXXCtorInitializer*[1];
4645  memcpy(initializer, &Initializer, sizeof (CXXCtorInitializer*));
4646  Constructor->setCtorInitializers(initializer);
4647 
4648  if (CXXDestructorDecl *Dtor = LookupDestructor(Constructor->getParent())) {
4649  MarkFunctionReferenced(Initializer->getSourceLocation(), Dtor);
4650  DiagnoseUseOfDecl(Dtor, Initializer->getSourceLocation());
4651  }
4652 
4653  DelegatingCtorDecls.push_back(Constructor);
4654 
4655  DiagnoseUninitializedFields(*this, Constructor);
4656 
4657  return false;
4658 }
4659 
4660 bool Sema::SetCtorInitializers(CXXConstructorDecl *Constructor, bool AnyErrors,
4661  ArrayRef<CXXCtorInitializer *> Initializers) {
4662  if (Constructor->isDependentContext()) {
4663  // Just store the initializers as written, they will be checked during
4664  // instantiation.
4665  if (!Initializers.empty()) {
4666  Constructor->setNumCtorInitializers(Initializers.size());
4667  CXXCtorInitializer **baseOrMemberInitializers =
4668  new (Context) CXXCtorInitializer*[Initializers.size()];
4669  memcpy(baseOrMemberInitializers, Initializers.data(),
4670  Initializers.size() * sizeof(CXXCtorInitializer*));
4671  Constructor->setCtorInitializers(baseOrMemberInitializers);
4672  }
4673 
4674  // Let template instantiation know whether we had errors.
4675  if (AnyErrors)
4676  Constructor->setInvalidDecl();
4677 
4678  return false;
4679  }
4680 
4681  BaseAndFieldInfo Info(*this, Constructor, AnyErrors);
4682 
4683  // We need to build the initializer AST according to order of construction
4684  // and not what user specified in the Initializers list.
4685  CXXRecordDecl *ClassDecl = Constructor->getParent()->getDefinition();
4686  if (!ClassDecl)
4687  return true;
4688 
4689  bool HadError = false;
4690 
4691  for (unsigned i = 0; i < Initializers.size(); i++) {
4692  CXXCtorInitializer *Member = Initializers[i];
4693 
4694  if (Member->isBaseInitializer())
4695  Info.AllBaseFields[Member->getBaseClass()->getAs<RecordType>()] = Member;
4696  else {
4697  Info.AllBaseFields[Member->getAnyMember()->getCanonicalDecl()] = Member;
4698 
4699  if (IndirectFieldDecl *F = Member->getIndirectMember()) {
4700  for (auto *C : F->chain()) {
4701  FieldDecl *FD = dyn_cast<FieldDecl>(C);
4702  if (FD && FD->getParent()->isUnion())
4703  Info.ActiveUnionMember.insert(std::make_pair(
4704  FD->getParent()->getCanonicalDecl(), FD->getCanonicalDecl()));
4705  }
4706  } else if (FieldDecl *FD = Member->getMember()) {
4707  if (FD->getParent()->isUnion())
4708  Info.ActiveUnionMember.insert(std::make_pair(
4709  FD->getParent()->getCanonicalDecl(), FD->getCanonicalDecl()));
4710  }
4711  }
4712  }
4713 
4714  // Keep track of the direct virtual bases.
4715  llvm::SmallPtrSet<CXXBaseSpecifier *, 16> DirectVBases;
4716  for (auto &I : ClassDecl->bases()) {
4717  if (I.isVirtual())
4718  DirectVBases.insert(&I);
4719  }
4720 
4721  // Push virtual bases before others.
4722  for (auto &VBase : ClassDecl->vbases()) {
4724  = Info.AllBaseFields.lookup(VBase.getType()->getAs<RecordType>())) {
4725  // [class.base.init]p7, per DR257:
4726  // A mem-initializer where the mem-initializer-id names a virtual base
4727  // class is ignored during execution of a constructor of any class that
4728  // is not the most derived class.
4729  if (ClassDecl->isAbstract()) {
4730  // FIXME: Provide a fixit to remove the base specifier. This requires
4731  // tracking the location of the associated comma for a base specifier.
4732  Diag(Value->getSourceLocation(), diag::warn_abstract_vbase_init_ignored)
4733  << VBase.getType() << ClassDecl;
4734  DiagnoseAbstractType(ClassDecl);
4735  }
4736 
4737  Info.AllToInit.push_back(Value);
4738  } else if (!AnyErrors && !ClassDecl->isAbstract()) {
4739  // [class.base.init]p8, per DR257:
4740  // If a given [...] base class is not named by a mem-initializer-id
4741  // [...] and the entity is not a virtual base class of an abstract
4742  // class, then [...] the entity is default-initialized.
4743  bool IsInheritedVirtualBase = !DirectVBases.count(&VBase);
4744  CXXCtorInitializer *CXXBaseInit;
4745  if (BuildImplicitBaseInitializer(*this, Constructor, Info.IIK,
4746  &VBase, IsInheritedVirtualBase,
4747  CXXBaseInit)) {
4748  HadError = true;
4749  continue;
4750  }
4751 
4752  Info.AllToInit.push_back(CXXBaseInit);
4753  }
4754  }
4755 
4756  // Non-virtual bases.
4757  for (auto &Base : ClassDecl->bases()) {
4758  // Virtuals are in the virtual base list and already constructed.
4759  if (Base.isVirtual())
4760  continue;
4761 
4763  = Info.AllBaseFields.lookup(Base.getType()->getAs<RecordType>())) {
4764  Info.AllToInit.push_back(Value);
4765  } else if (!AnyErrors) {
4766  CXXCtorInitializer *CXXBaseInit;
4767  if (BuildImplicitBaseInitializer(*this, Constructor, Info.IIK,
4768  &Base, /*IsInheritedVirtualBase=*/false,
4769  CXXBaseInit)) {
4770  HadError = true;
4771  continue;
4772  }
4773 
4774  Info.AllToInit.push_back(CXXBaseInit);
4775  }
4776  }
4777 
4778  // Fields.
4779  for (auto *Mem : ClassDecl->decls()) {
4780  if (auto *F = dyn_cast<FieldDecl>(Mem)) {
4781  // C++ [class.bit]p2:
4782  // A declaration for a bit-field that omits the identifier declares an
4783  // unnamed bit-field. Unnamed bit-fields are not members and cannot be
4784  // initialized.
4785  if (F->isUnnamedBitfield())
4786  continue;
4787 
4788  // If we're not generating the implicit copy/move constructor, then we'll
4789  // handle anonymous struct/union fields based on their individual
4790  // indirect fields.
4791  if (F->isAnonymousStructOrUnion() && !Info.isImplicitCopyOrMove())
4792  continue;
4793 
4794  if (CollectFieldInitializer(*this, Info, F))
4795  HadError = true;
4796  continue;
4797  }
4798 
4799  // Beyond this point, we only consider default initialization.
4800  if (Info.isImplicitCopyOrMove())
4801  continue;
4802 
4803  if (auto *F = dyn_cast<IndirectFieldDecl>(Mem)) {
4804  if (F->getType()->isIncompleteArrayType()) {
4805  assert(ClassDecl->hasFlexibleArrayMember() &&
4806  "Incomplete array type is not valid");
4807  continue;
4808  }
4809 
4810  // Initialize each field of an anonymous struct individually.
4811  if (CollectFieldInitializer(*this, Info, F->getAnonField(), F))
4812  HadError = true;
4813 
4814  continue;
4815  }
4816  }
4817 
4818  unsigned NumInitializers = Info.AllToInit.size();
4819  if (NumInitializers > 0) {
4820  Constructor->setNumCtorInitializers(NumInitializers);
4821  CXXCtorInitializer **baseOrMemberInitializers =
4822  new (Context) CXXCtorInitializer*[NumInitializers];
4823  memcpy(baseOrMemberInitializers, Info.AllToInit.data(),
4824  NumInitializers * sizeof(CXXCtorInitializer*));
4825  Constructor->setCtorInitializers(baseOrMemberInitializers);
4826 
4827  // Constructors implicitly reference the base and member
4828  // destructors.
4829  MarkBaseAndMemberDestructorsReferenced(Constructor->getLocation(),
4830  Constructor->getParent());
4831  }
4832 
4833  return HadError;
4834 }
4835 
4837  if (const RecordType *RT = Field->getType()->getAs<RecordType>()) {
4838  const RecordDecl *RD = RT->getDecl();
4839  if (RD->isAnonymousStructOrUnion()) {
4840  for (auto *Field : RD->fields())
4841  PopulateKeysForFields(Field, IdealInits);
4842  return;
4843  }
4844  }
4845  IdealInits.push_back(Field->getCanonicalDecl());
4846 }
4847 
4848 static const void *GetKeyForBase(ASTContext &Context, QualType BaseType) {
4849  return Context.getCanonicalType(BaseType).getTypePtr();
4850 }
4851 
4852 static const void *GetKeyForMember(ASTContext &Context,
4853  CXXCtorInitializer *Member) {
4854  if (!Member->isAnyMemberInitializer())
4855  return GetKeyForBase(Context, QualType(Member->getBaseClass(), 0));
4856 
4857  return Member->getAnyMember()->getCanonicalDecl();
4858 }
4859 
4861  Sema &SemaRef, const CXXConstructorDecl *Constructor,
4863  if (Constructor->getDeclContext()->isDependentContext())
4864  return;
4865 
4866  // Don't check initializers order unless the warning is enabled at the
4867  // location of at least one initializer.
4868  bool ShouldCheckOrder = false;
4869  for (unsigned InitIndex = 0; InitIndex != Inits.size(); ++InitIndex) {
4870  CXXCtorInitializer *Init = Inits[InitIndex];
4871  if (!SemaRef.Diags.isIgnored(diag::warn_initializer_out_of_order,
4872  Init->getSourceLocation())) {
4873  ShouldCheckOrder = true;
4874  break;
4875  }
4876  }
4877  if (!ShouldCheckOrder)
4878  return;
4879 
4880  // Build the list of bases and members in the order that they'll
4881  // actually be initialized. The explicit initializers should be in
4882  // this same order but may be missing things.
4883  SmallVector<const void*, 32> IdealInitKeys;
4884 
4885  const CXXRecordDecl *ClassDecl = Constructor->getParent();
4886 
4887  // 1. Virtual bases.
4888  for (const auto &VBase : ClassDecl->vbases())
4889  IdealInitKeys.push_back(GetKeyForBase(SemaRef.Context, VBase.getType()));
4890 
4891  // 2. Non-virtual bases.
4892  for (const auto &Base : ClassDecl->bases()) {
4893  if (Base.isVirtual())
4894  continue;
4895  IdealInitKeys.push_back(GetKeyForBase(SemaRef.Context, Base.getType()));
4896  }
4897 
4898  // 3. Direct fields.
4899  for (auto *Field : ClassDecl->fields()) {
4900  if (Field->isUnnamedBitfield())
4901  continue;
4902 
4903  PopulateKeysForFields(Field, IdealInitKeys);
4904  }
4905 
4906  unsigned NumIdealInits = IdealInitKeys.size();
4907  unsigned IdealIndex = 0;
4908 
4909  CXXCtorInitializer *PrevInit = nullptr;
4910  for (unsigned InitIndex = 0; InitIndex != Inits.size(); ++InitIndex) {
4911  CXXCtorInitializer *Init = Inits[InitIndex];
4912  const void *InitKey = GetKeyForMember(SemaRef.Context, Init);
4913 
4914  // Scan forward to try to find this initializer in the idealized
4915  // initializers list.
4916  for (; IdealIndex != NumIdealInits; ++IdealIndex)
4917  if (InitKey == IdealInitKeys[IdealIndex])
4918  break;
4919 
4920  // If we didn't find this initializer, it must be because we
4921  // scanned past it on a previous iteration. That can only
4922  // happen if we're out of order; emit a warning.
4923  if (IdealIndex == NumIdealInits && PrevInit) {
4925  SemaRef.Diag(PrevInit->getSourceLocation(),
4926  diag::warn_initializer_out_of_order);
4927 
4928  if (PrevInit->isAnyMemberInitializer())
4929  D << 0 << PrevInit->getAnyMember()->getDeclName();
4930  else
4931  D << 1 << PrevInit->getTypeSourceInfo()->getType();
4932 
4933  if (Init->isAnyMemberInitializer())
4934  D << 0 << Init->getAnyMember()->getDeclName();
4935  else
4936  D << 1 << Init->getTypeSourceInfo()->getType();
4937 
4938  // Move back to the initializer's location in the ideal list.
4939  for (IdealIndex = 0; IdealIndex != NumIdealInits; ++IdealIndex)
4940  if (InitKey == IdealInitKeys[IdealIndex])
4941  break;
4942 
4943  assert(IdealIndex < NumIdealInits &&
4944  "initializer not found in initializer list");
4945  }
4946 
4947  PrevInit = Init;
4948  }
4949 }
4950 
4951 namespace {
4952 bool CheckRedundantInit(Sema &S,
4953  CXXCtorInitializer *Init,
4954  CXXCtorInitializer *&PrevInit) {
4955  if (!PrevInit) {
4956  PrevInit = Init;
4957  return false;
4958  }
4959 
4960  if (FieldDecl *Field = Init->getAnyMember())
4961  S.Diag(Init->getSourceLocation(),
4962  diag::err_multiple_mem_initialization)
4963  << Field->getDeclName()
4964  << Init->getSourceRange();
4965  else {
4966  const Type *BaseClass = Init->getBaseClass();
4967  assert(BaseClass && "neither field nor base");
4968  S.Diag(Init->getSourceLocation(),
4969  diag::err_multiple_base_initialization)
4970  << QualType(BaseClass, 0)
4971  << Init->getSourceRange();
4972  }
4973  S.Diag(PrevInit->getSourceLocation(), diag::note_previous_initializer)
4974  << 0 << PrevInit->getSourceRange();
4975 
4976  return true;
4977 }
4978 
4979 typedef std::pair<NamedDecl *, CXXCtorInitializer *> UnionEntry;
4980 typedef llvm::DenseMap<RecordDecl*, UnionEntry> RedundantUnionMap;
4981 
4982 bool CheckRedundantUnionInit(Sema &S,
4983  CXXCtorInitializer *Init,
4984  RedundantUnionMap &Unions) {
4985  FieldDecl *Field = Init->getAnyMember();
4986  RecordDecl *Parent = Field->getParent();
4987  NamedDecl *Child = Field;
4988 
4989  while (Parent->isAnonymousStructOrUnion() || Parent->isUnion()) {
4990  if (Parent->isUnion()) {
4991  UnionEntry &En = Unions[Parent];
4992  if (En.first && En.first != Child) {
4993  S.Diag(Init->getSourceLocation(),
4994  diag::err_multiple_mem_union_initialization)
4995  << Field->getDeclName()
4996  << Init->getSourceRange();
4997  S.Diag(En.second->getSourceLocation(), diag::note_previous_initializer)
4998  << 0 << En.second->getSourceRange();
4999  return true;
5000  }
5001  if (!En.first) {
5002  En.first = Child;
5003  En.second = Init;
5004  }
5005  if (!Parent->isAnonymousStructOrUnion())
5006  return false;
5007  }
5008 
5009  Child = Parent;
5010  Parent = cast<RecordDecl>(Parent->getDeclContext());
5011  }
5012 
5013  return false;
5014 }
5015 }
5016 
5017 /// ActOnMemInitializers - Handle the member initializers for a constructor.
5018 void Sema::ActOnMemInitializers(Decl *ConstructorDecl,
5021  bool AnyErrors) {
5022  if (!ConstructorDecl)
5023  return;
5024 
5025  AdjustDeclIfTemplate(ConstructorDecl);
5026 
5027  CXXConstructorDecl *Constructor
5028  = dyn_cast<CXXConstructorDecl>(ConstructorDecl);
5029 
5030  if (!Constructor) {
5031  Diag(ColonLoc, diag::err_only_constructors_take_base_inits);
5032  return;
5033  }
5034 
5035  // Mapping for the duplicate initializers check.
5036  // For member initializers, this is keyed with a FieldDecl*.
5037  // For base initializers, this is keyed with a Type*.
5038  llvm::DenseMap<const void *, CXXCtorInitializer *> Members;
5039 
5040  // Mapping for the inconsistent anonymous-union initializers check.
5041  RedundantUnionMap MemberUnions;
5042 
5043  bool HadError = false;
5044  for (unsigned i = 0; i < MemInits.size(); i++) {
5045  CXXCtorInitializer *Init = MemInits[i];
5046 
5047  // Set the source order index.
5048  Init->setSourceOrder(i);
5049 
5050  if (Init->isAnyMemberInitializer()) {
5051  const void *Key = GetKeyForMember(Context, Init);
5052  if (CheckRedundantInit(*this, Init, Members[Key]) ||
5053  CheckRedundantUnionInit(*this, Init, MemberUnions))
5054  HadError = true;
5055  } else if (Init->isBaseInitializer()) {
5056  const void *Key = GetKeyForMember(Context, Init);
5057  if (CheckRedundantInit(*this, Init, Members[Key]))
5058  HadError = true;
5059  } else {
5060  assert(Init->isDelegatingInitializer());
5061  // This must be the only initializer
5062  if (MemInits.size() != 1) {
5063  Diag(Init->getSourceLocation(),
5064  diag::err_delegating_initializer_alone)
5065  << Init->getSourceRange() << MemInits[i ? 0 : 1]->getSourceRange();
5066  // We will treat this as being the only initializer.
5067  }
5068  SetDelegatingInitializer(Constructor, MemInits[i]);
5069  // Return immediately as the initializer is set.
5070  return;
5071  }
5072  }
5073 
5074  if (HadError)
5075  return;
5076 
5077  DiagnoseBaseOrMemInitializerOrder(*this, Constructor, MemInits);
5078 
5079  SetCtorInitializers(Constructor, AnyErrors, MemInits);
5080 
5081  DiagnoseUninitializedFields(*this, Constructor);
5082 }
5083 
5084 void
5086  CXXRecordDecl *ClassDecl) {
5087  // Ignore dependent contexts. Also ignore unions, since their members never
5088  // have destructors implicitly called.
5089  if (ClassDecl->isDependentContext() || ClassDecl->isUnion())
5090  return;
5091 
5092  // FIXME: all the access-control diagnostics are positioned on the
5093  // field/base declaration. That's probably good; that said, the
5094  // user might reasonably want to know why the destructor is being
5095  // emitted, and we currently don't say.
5096 
5097  // Non-static data members.
5098  for (auto *Field : ClassDecl->fields()) {
5099  if (Field->isInvalidDecl())
5100  continue;
5101 
5102  // Don't destroy incomplete or zero-length arrays.
5103  if (isIncompleteOrZeroLengthArrayType(Context, Field->getType()))
5104  continue;
5105 
5106  QualType FieldType = Context.getBaseElementType(Field->getType());
5107 
5108  const RecordType* RT = FieldType->getAs<RecordType>();
5109  if (!RT)
5110  continue;
5111 
5112  CXXRecordDecl *FieldClassDecl = cast<CXXRecordDecl>(RT->getDecl());
5113  if (FieldClassDecl->isInvalidDecl())
5114  continue;
5115  if (FieldClassDecl->hasIrrelevantDestructor())
5116  continue;
5117  // The destructor for an implicit anonymous union member is never invoked.
5118  if (FieldClassDecl->isUnion() && FieldClassDecl->isAnonymousStructOrUnion())
5119  continue;
5120 
5121  CXXDestructorDecl *Dtor = LookupDestructor(FieldClassDecl);
5122  assert(Dtor && "No dtor found for FieldClassDecl!");
5123  CheckDestructorAccess(Field->getLocation(), Dtor,
5124  PDiag(diag::err_access_dtor_field)
5125  << Field->getDeclName()
5126  << FieldType);
5127 
5128  MarkFunctionReferenced(Location, Dtor);
5129  DiagnoseUseOfDecl(Dtor, Location);
5130  }
5131 
5132  // We only potentially invoke the destructors of potentially constructed
5133  // subobjects.
5134  bool VisitVirtualBases = !ClassDecl->isAbstract();
5135 
5136  llvm::SmallPtrSet<const RecordType *, 8> DirectVirtualBases;
5137 
5138  // Bases.
5139  for (const auto &Base : ClassDecl->bases()) {
5140  // Bases are always records in a well-formed non-dependent class.
5141  const RecordType *RT = Base.getType()->getAs<RecordType>();
5142 
5143  // Remember direct virtual bases.
5144  if (Base.isVirtual()) {
5145  if (!VisitVirtualBases)
5146  continue;
5147  DirectVirtualBases.insert(RT);
5148  }
5149 
5150  CXXRecordDecl *BaseClassDecl = cast<CXXRecordDecl>(RT->getDecl());
5151  // If our base class is invalid, we probably can't get its dtor anyway.
5152  if (BaseClassDecl->isInvalidDecl())
5153  continue;
5154  if (BaseClassDecl->hasIrrelevantDestructor())
5155  continue;
5156 
5157  CXXDestructorDecl *Dtor = LookupDestructor(BaseClassDecl);
5158  assert(Dtor && "No dtor found for BaseClassDecl!");
5159 
5160  // FIXME: caret should be on the start of the class name
5161  CheckDestructorAccess(Base.getLocStart(), Dtor,
5162  PDiag(diag::err_access_dtor_base)
5163  << Base.getType()
5164  << Base.getSourceRange(),
5165  Context.getTypeDeclType(ClassDecl));
5166 
5167  MarkFunctionReferenced(Location, Dtor);
5168  DiagnoseUseOfDecl(Dtor, Location);
5169  }
5170 
5171  if (!VisitVirtualBases)
5172  return;
5173 
5174  // Virtual bases.
5175  for (const auto &VBase : ClassDecl->vbases()) {
5176  // Bases are always records in a well-formed non-dependent class.
5177  const RecordType *RT = VBase.getType()->castAs<RecordType>();
5178 
5179  // Ignore direct virtual bases.
5180  if (DirectVirtualBases.count(RT))
5181  continue;
5182 
5183  CXXRecordDecl *BaseClassDecl = cast<CXXRecordDecl>(RT->getDecl());
5184  // If our base class is invalid, we probably can't get its dtor anyway.
5185  if (BaseClassDecl->isInvalidDecl())
5186  continue;
5187  if (BaseClassDecl->hasIrrelevantDestructor())
5188  continue;
5189 
5190  CXXDestructorDecl *Dtor = LookupDestructor(BaseClassDecl);
5191  assert(Dtor && "No dtor found for BaseClassDecl!");
5192  if (CheckDestructorAccess(
5193  ClassDecl->getLocation(), Dtor,
5194  PDiag(diag::err_access_dtor_vbase)
5195  << Context.getTypeDeclType(ClassDecl) << VBase.getType(),
5196  Context.getTypeDeclType(ClassDecl)) ==
5197  AR_accessible) {
5198  CheckDerivedToBaseConversion(
5199  Context.getTypeDeclType(ClassDecl), VBase.getType(),
5200  diag::err_access_dtor_vbase, 0, ClassDecl->getLocation(),
5201  SourceRange(), DeclarationName(), nullptr);
5202  }
5203 
5204  MarkFunctionReferenced(Location, Dtor);
5205  DiagnoseUseOfDecl(Dtor, Location);
5206  }
5207 }
5208 
5209 void Sema::ActOnDefaultCtorInitializers(Decl *CDtorDecl) {
5210  if (!CDtorDecl)
5211  return;
5212 
5213  if (CXXConstructorDecl *Constructor
5214  = dyn_cast<CXXConstructorDecl>(CDtorDecl)) {
5215  SetCtorInitializers(Constructor, /*AnyErrors=*/false);
5216  DiagnoseUninitializedFields(*this, Constructor);
5217  }
5218 }
5219 
5221  if (!getLangOpts().CPlusPlus)
5222  return false;
5223 
5224  const auto *RD = Context.getBaseElementType(T)->getAsCXXRecordDecl();
5225  if (!RD)
5226  return false;
5227 
5228  // FIXME: Per [temp.inst]p1, we are supposed to trigger instantiation of a
5229  // class template specialization here, but doing so breaks a lot of code.
5230 
5231  // We can't answer whether something is abstract until it has a
5232  // definition. If it's currently being defined, we'll walk back
5233  // over all the declarations when we have a full definition.
5234  const CXXRecordDecl *Def = RD->getDefinition();
5235  if (!Def || Def->isBeingDefined())
5236  return false;
5237 
5238  return RD->isAbstract();
5239 }
5240 
5242  TypeDiagnoser &Diagnoser) {
5243  if (!isAbstractType(Loc, T))
5244  return false;
5245 
5246  T = Context.getBaseElementType(T);
5247  Diagnoser.diagnose(*this, Loc, T);
5248  DiagnoseAbstractType(T->getAsCXXRecordDecl());
5249  return true;
5250 }
5251 
5253  // Check if we've already emitted the list of pure virtual functions
5254  // for this class.
5255  if (PureVirtualClassDiagSet && PureVirtualClassDiagSet->count(RD))
5256  return;
5257 
5258  // If the diagnostic is suppressed, don't emit the notes. We're only
5259  // going to emit them once, so try to attach them to a diagnostic we're
5260  // actually going to show.
5261  if (Diags.isLastDiagnosticIgnored())
5262  return;
5263 
5264  CXXFinalOverriderMap FinalOverriders;
5265  RD->getFinalOverriders(FinalOverriders);
5266 
5267  // Keep a set of seen pure methods so we won't diagnose the same method
5268  // more than once.
5269  llvm::SmallPtrSet<const CXXMethodDecl *, 8> SeenPureMethods;
5270 
5271  for (CXXFinalOverriderMap::iterator M = FinalOverriders.begin(),
5272  MEnd = FinalOverriders.end();
5273  M != MEnd;
5274  ++M) {
5275  for (OverridingMethods::iterator SO = M->second.begin(),
5276  SOEnd = M->second.end();
5277  SO != SOEnd; ++SO) {
5278  // C++ [class.abstract]p4:
5279  // A class is abstract if it contains or inherits at least one
5280  // pure virtual function for which the final overrider is pure
5281  // virtual.
5282 
5283  //
5284  if (SO->second.size() != 1)
5285  continue;
5286 
5287  if (!SO->second.front().Method->isPure())
5288  continue;
5289 
5290  if (!SeenPureMethods.insert(SO->second.front().Method).second)
5291  continue;
5292 
5293  Diag(SO->second.front().Method->getLocation(),
5294  diag::note_pure_virtual_function)
5295  << SO->second.front().Method->getDeclName() << RD->getDeclName();
5296  }
5297  }
5298 
5299  if (!PureVirtualClassDiagSet)
5300  PureVirtualClassDiagSet.reset(new RecordDeclSetTy);
5301  PureVirtualClassDiagSet->insert(RD);
5302 }
5303 
5304 namespace {
5305 struct AbstractUsageInfo {
5306  Sema &S;
5307  CXXRecordDecl *Record;
5308  CanQualType AbstractType;
5309  bool Invalid;
5310 
5311  AbstractUsageInfo(Sema &S, CXXRecordDecl *Record)
5312  : S(S), Record(Record),
5313  AbstractType(S.Context.getCanonicalType(
5314  S.Context.getTypeDeclType(Record))),
5315  Invalid(false) {}
5316 
5317  void DiagnoseAbstractType() {
5318  if (Invalid) return;
5319  S.DiagnoseAbstractType(Record);
5320  Invalid = true;
5321  }
5322 
5323  void CheckType(const NamedDecl *D, TypeLoc TL, Sema::AbstractDiagSelID Sel);
5324 };
5325 
5326 struct CheckAbstractUsage {
5327  AbstractUsageInfo &Info;
5328  const NamedDecl *Ctx;
5329 
5330  CheckAbstractUsage(AbstractUsageInfo &Info, const NamedDecl *Ctx)
5331  : Info(Info), Ctx(Ctx) {}
5332 
5333  void Visit(TypeLoc TL, Sema::AbstractDiagSelID Sel) {
5334  switch (TL.getTypeLocClass()) {
5335 #define ABSTRACT_TYPELOC(CLASS, PARENT)
5336 #define TYPELOC(CLASS, PARENT) \
5337  case TypeLoc::CLASS: Check(TL.castAs<CLASS##TypeLoc>(), Sel); break;
5338 #include "clang/AST/TypeLocNodes.def"
5339  }
5340  }
5341 
5342  void Check(FunctionProtoTypeLoc TL, Sema::AbstractDiagSelID Sel) {
5344  for (unsigned I = 0, E = TL.getNumParams(); I != E; ++I) {
5345  if (!TL.getParam(I))
5346  continue;
5347 
5348  TypeSourceInfo *TSI = TL.getParam(I)->getTypeSourceInfo();
5349  if (TSI) Visit(TSI->getTypeLoc(), Sema::AbstractParamType);
5350  }
5351  }
5352 
5353  void Check(ArrayTypeLoc TL, Sema::AbstractDiagSelID Sel) {
5355  }
5356 
5358  // Visit the type parameters from a permissive context.
5359  for (unsigned I = 0, E = TL.getNumArgs(); I != E; ++I) {
5360  TemplateArgumentLoc TAL = TL.getArgLoc(I);
5362  if (TypeSourceInfo *TSI = TAL.getTypeSourceInfo())
5363  Visit(TSI->getTypeLoc(), Sema::AbstractNone);
5364  // TODO: other template argument types?
5365  }
5366  }
5367 
5368  // Visit pointee types from a permissive context.
5369 #define CheckPolymorphic(Type) \
5370  void Check(Type TL, Sema::AbstractDiagSelID Sel) { \
5371  Visit(TL.getNextTypeLoc(), Sema::AbstractNone); \
5372  }
5378 
5379  /// Handle all the types we haven't given a more specific
5380  /// implementation for above.
5381  void Check(TypeLoc TL, Sema::AbstractDiagSelID Sel) {
5382  // Every other kind of type that we haven't called out already
5383  // that has an inner type is either (1) sugar or (2) contains that
5384  // inner type in some way as a subobject.
5385  if (TypeLoc Next = TL.getNextTypeLoc())
5386  return Visit(Next, Sel);
5387 
5388  // If there's no inner type and we're in a permissive context,
5389  // don't diagnose.
5390  if (Sel == Sema::AbstractNone) return;
5391 
5392  // Check whether the type matches the abstract type.
5393  QualType T = TL.getType();
5394  if (T->isArrayType()) {
5396  T = Info.S.Context.getBaseElementType(T);
5397  }
5399  if (CT != Info.AbstractType) return;
5400 
5401  // It matched; do some magic.
5402  if (Sel == Sema::AbstractArrayType) {
5403  Info.S.Diag(Ctx->getLocation(), diag::err_array_of_abstract_type)
5404  << T << TL.getSourceRange();
5405  } else {
5406  Info.S.Diag(Ctx->getLocation(), diag::err_abstract_type_in_decl)
5407  << Sel << T << TL.getSourceRange();
5408  }
5409  Info.DiagnoseAbstractType();
5410  }
5411 };
5412 
5413 void AbstractUsageInfo::CheckType(const NamedDecl *D, TypeLoc TL,
5415  CheckAbstractUsage(*this, D).Visit(TL, Sel);
5416 }
5417 
5418 }
5419 
5420 /// Check for invalid uses of an abstract type in a method declaration.
5421 static void CheckAbstractClassUsage(AbstractUsageInfo &Info,
5422  CXXMethodDecl *MD) {
5423  // No need to do the check on definitions, which require that
5424  // the return/param types be complete.
5425  if (MD->doesThisDeclarationHaveABody())
5426  return;
5427 
5428  // For safety's sake, just ignore it if we don't have type source
5429  // information. This should never happen for non-implicit methods,
5430  // but...
5431  if (TypeSourceInfo *TSI = MD->getTypeSourceInfo())
5432  Info.CheckType(MD, TSI->getTypeLoc(), Sema::AbstractNone);
5433 }
5434 
5435 /// Check for invalid uses of an abstract type within a class definition.
5436 static void CheckAbstractClassUsage(AbstractUsageInfo &Info,
5437  CXXRecordDecl *RD) {
5438  for (auto *D : RD->decls()) {
5439  if (D->isImplicit()) continue;
5440 
5441  // Methods and method templates.
5442  if (isa<CXXMethodDecl>(D)) {
5443  CheckAbstractClassUsage(Info, cast<CXXMethodDecl>(D));
5444  } else if (isa<FunctionTemplateDecl>(D)) {
5445  FunctionDecl *FD = cast<FunctionTemplateDecl>(D)->getTemplatedDecl();
5446  CheckAbstractClassUsage(Info, cast<CXXMethodDecl>(FD));
5447 
5448  // Fields and static variables.
5449  } else if (isa<FieldDecl>(D)) {
5450  FieldDecl *FD = cast<FieldDecl>(D);
5451  if (TypeSourceInfo *TSI = FD->getTypeSourceInfo())
5452  Info.CheckType(FD, TSI->getTypeLoc(), Sema::AbstractFieldType);
5453  } else if (isa<VarDecl>(D)) {
5454  VarDecl *VD = cast<VarDecl>(D);
5455  if (TypeSourceInfo *TSI = VD->getTypeSourceInfo())
5456  Info.CheckType(VD, TSI->getTypeLoc(), Sema::AbstractVariableType);
5457 
5458  // Nested classes and class templates.
5459  } else if (isa<CXXRecordDecl>(D)) {
5460  CheckAbstractClassUsage(Info, cast<CXXRecordDecl>(D));
5461  } else if (isa<ClassTemplateDecl>(D)) {
5463  cast<ClassTemplateDecl>(D)->getTemplatedDecl());
5464  }
5465  }
5466 }
5467 
5469  Attr *ClassAttr = getDLLAttr(Class);
5470  if (!ClassAttr)
5471  return;
5472 
5473  assert(ClassAttr->getKind() == attr::DLLExport);
5474 
5476 
5478  // Don't go any further if this is just an explicit instantiation
5479  // declaration.
5480  return;
5481 
5482  for (Decl *Member : Class->decls()) {
5483  auto *MD = dyn_cast<CXXMethodDecl>(Member);
5484  if (!MD)
5485  continue;
5486 
5487  if (Member->getAttr<DLLExportAttr>()) {
5488  if (MD->isUserProvided()) {
5489  // Instantiate non-default class member functions ...
5490 
5491  // .. except for certain kinds of template specializations.
5492  if (TSK == TSK_ImplicitInstantiation && !ClassAttr->isInherited())
5493  continue;
5494 
5495  S.MarkFunctionReferenced(Class->getLocation(), MD);
5496 
5497  // The function will be passed to the consumer when its definition is
5498  // encountered.
5499  } else if (!MD->isTrivial() || MD->isExplicitlyDefaulted() ||
5500  MD->isCopyAssignmentOperator() ||
5501  MD->isMoveAssignmentOperator()) {
5502  // Synthesize and instantiate non-trivial implicit methods, explicitly
5503  // defaulted methods, and the copy and move assignment operators. The
5504  // latter are exported even if they are trivial, because the address of
5505  // an operator can be taken and should compare equal across libraries.
5506  DiagnosticErrorTrap Trap(S.Diags);
5507  S.MarkFunctionReferenced(Class->getLocation(), MD);
5508  if (Trap.hasErrorOccurred()) {
5509  S.Diag(ClassAttr->getLocation(), diag::note_due_to_dllexported_class)
5510  << Class->getName() << !S.getLangOpts().CPlusPlus11;
5511  break;
5512  }
5513 
5514  // There is no later point when we will see the definition of this
5515  // function, so pass it to the consumer now.
5517  }
5518  }
5519  }
5520 }
5521 
5523  CXXRecordDecl *Class) {
5524  // Only the MS ABI has default constructor closures, so we don't need to do
5525  // this semantic checking anywhere else.
5527  return;
5528 
5529  CXXConstructorDecl *LastExportedDefaultCtor = nullptr;
5530  for (Decl *Member : Class->decls()) {
5531  // Look for exported default constructors.
5532  auto *CD = dyn_cast<CXXConstructorDecl>(Member);
5533  if (!CD || !CD->isDefaultConstructor())
5534  continue;
5535  auto *Attr = CD->getAttr<DLLExportAttr>();
5536  if (!Attr)
5537  continue;
5538 
5539  // If the class is non-dependent, mark the default arguments as ODR-used so
5540  // that we can properly codegen the constructor closure.
5541  if (!Class->isDependentContext()) {
5542  for (ParmVarDecl *PD : CD->parameters()) {
5543  (void)S.CheckCXXDefaultArgExpr(Attr->getLocation(), CD, PD);
5545  }
5546  }
5547 
5548  if (LastExportedDefaultCtor) {
5549  S.Diag(LastExportedDefaultCtor->getLocation(),
5550  diag::err_attribute_dll_ambiguous_default_ctor)
5551  << Class;
5552  S.Diag(CD->getLocation(), diag::note_entity_declared_at)
5553  << CD->getDeclName();
5554  return;
5555  }
5556  LastExportedDefaultCtor = CD;
5557  }
5558 }
5559 
5560 /// \brief Check class-level dllimport/dllexport attribute.
5562  Attr *ClassAttr = getDLLAttr(Class);
5563 
5564  // MSVC inherits DLL attributes to partial class template specializations.
5565  if (Context.getTargetInfo().getCXXABI().isMicrosoft() && !ClassAttr) {
5566  if (auto *Spec = dyn_cast<ClassTemplatePartialSpecializationDecl>(Class)) {
5567  if (Attr *TemplateAttr =
5568  getDLLAttr(Spec->getSpecializedTemplate()->getTemplatedDecl())) {
5569  auto *A = cast<InheritableAttr>(TemplateAttr->clone(getASTContext()));
5570  A->setInherited(true);
5571  ClassAttr = A;
5572  }
5573  }
5574  }
5575 
5576  if (!ClassAttr)
5577  return;
5578 
5579  if (!Class->isExternallyVisible()) {
5580  Diag(Class->getLocation(), diag::err_attribute_dll_not_extern)
5581  << Class << ClassAttr;
5582  return;
5583  }
5584 
5585  if (Context.getTargetInfo().getCXXABI().isMicrosoft() &&
5586  !ClassAttr->isInherited()) {
5587  // Diagnose dll attributes on members of class with dll attribute.
5588  for (Decl *Member : Class->decls()) {
5589  if (!isa<VarDecl>(Member) && !isa<CXXMethodDecl>(Member))
5590  continue;
5591  InheritableAttr *MemberAttr = getDLLAttr(Member);
5592  if (!MemberAttr || MemberAttr->isInherited() || Member->isInvalidDecl())
5593  continue;
5594 
5595  Diag(MemberAttr->getLocation(),
5596  diag::err_attribute_dll_member_of_dll_class)
5597  << MemberAttr << ClassAttr;
5598  Diag(ClassAttr->getLocation(), diag::note_previous_attribute);
5599  Member->setInvalidDecl();
5600  }
5601  }
5602 
5603  if (Class->getDescribedClassTemplate())
5604  // Don't inherit dll attribute until the template is instantiated.
5605  return;
5606 
5607  // The class is either imported or exported.
5608  const bool ClassExported = ClassAttr->getKind() == attr::DLLExport;
5609 
5611 
5612  // Ignore explicit dllexport on explicit class template instantiation declarations.
5613  if (ClassExported && !ClassAttr->isInherited() &&
5615  Class->dropAttr<DLLExportAttr>();
5616  return;
5617  }
5618 
5619  // Force declaration of implicit members so they can inherit the attribute.
5620  ForceDeclarationOfImplicitMembers(Class);
5621 
5622  // FIXME: MSVC's docs say all bases must be exportable, but this doesn't
5623  // seem to be true in practice?
5624 
5625  for (Decl *Member : Class->decls()) {
5626  VarDecl *VD = dyn_cast<VarDecl>(Member);
5627  CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(Member);
5628 
5629  // Only methods and static fields inherit the attributes.
5630  if (!VD && !MD)
5631  continue;
5632 
5633  if (MD) {
5634  // Don't process deleted methods.
5635  if (MD->isDeleted())
5636  continue;
5637 
5638  if (MD->isInlined()) {
5639  // MinGW does not import or export inline methods.
5640  if (!Context.getTargetInfo().getCXXABI().isMicrosoft() &&
5641  !Context.getTargetInfo().getTriple().isWindowsItaniumEnvironment())
5642  continue;
5643 
5644  // MSVC versions before 2015 don't export the move assignment operators
5645  // and move constructor, so don't attempt to import/export them if
5646  // we have a definition.
5647  auto *Ctor = dyn_cast<CXXConstructorDecl>(MD);
5648  if ((MD->isMoveAssignmentOperator() ||
5649  (Ctor && Ctor->isMoveConstructor())) &&
5650  !getLangOpts().isCompatibleWithMSVC(LangOptions::MSVC2015))
5651  continue;
5652 
5653  // MSVC2015 doesn't export trivial defaulted x-tor but copy assign
5654  // operator is exported anyway.
5655  if (getLangOpts().isCompatibleWithMSVC(LangOptions::MSVC2015) &&
5656  (Ctor || isa<CXXDestructorDecl>(MD)) && MD->isTrivial())
5657  continue;
5658  }
5659  }
5660 
5661  if (!cast<NamedDecl>(Member)->isExternallyVisible())
5662  continue;
5663 
5664  if (!getDLLAttr(Member)) {
5665  auto *NewAttr =
5666  cast<InheritableAttr>(ClassAttr->clone(getASTContext()));
5667  NewAttr->setInherited(true);
5668  Member->addAttr(NewAttr);
5669  }
5670  }
5671 
5672  if (ClassExported)
5673  DelayedDllExportClasses.push_back(Class);
5674 }
5675 
5676 /// \brief Perform propagation of DLL attributes from a derived class to a
5677 /// templated base class for MS compatibility.
5679  CXXRecordDecl *Class, Attr *ClassAttr,
5680  ClassTemplateSpecializationDecl *BaseTemplateSpec, SourceLocation BaseLoc) {
5681  if (getDLLAttr(
5682  BaseTemplateSpec->getSpecializedTemplate()->getTemplatedDecl())) {
5683  // If the base class template has a DLL attribute, don't try to change it.
5684  return;
5685  }
5686 
5687  auto TSK = BaseTemplateSpec->getSpecializationKind();
5688  if (!getDLLAttr(BaseTemplateSpec) &&
5690  TSK == TSK_ImplicitInstantiation)) {
5691  // The template hasn't been instantiated yet (or it has, but only as an
5692  // explicit instantiation declaration or implicit instantiation, which means
5693  // we haven't codegenned any members yet), so propagate the attribute.
5694  auto *NewAttr = cast<InheritableAttr>(ClassAttr->clone(getASTContext()));
5695  NewAttr->setInherited(true);
5696  BaseTemplateSpec->addAttr(NewAttr);
5697 
5698  // If the template is already instantiated, checkDLLAttributeRedeclaration()
5699  // needs to be run again to work see the new attribute. Otherwise this will
5700  // get run whenever the template is instantiated.
5701  if (TSK != TSK_Undeclared)
5702  checkClassLevelDLLAttribute(BaseTemplateSpec);
5703 
5704  return;
5705  }
5706 
5707  if (getDLLAttr(BaseTemplateSpec)) {
5708  // The template has already been specialized or instantiated with an
5709  // attribute, explicitly or through propagation. We should not try to change
5710