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SemaLambda.cpp
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1 //===--- SemaLambda.cpp - Semantic Analysis for C++11 Lambdas -------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file implements semantic analysis for C++ lambda expressions.
10 //
11 //===----------------------------------------------------------------------===//
12 #include "clang/Sema/DeclSpec.h"
13 #include "TypeLocBuilder.h"
14 #include "clang/AST/ASTLambda.h"
15 #include "clang/AST/ExprCXX.h"
16 #include "clang/Basic/TargetInfo.h"
18 #include "clang/Sema/Lookup.h"
19 #include "clang/Sema/Scope.h"
20 #include "clang/Sema/ScopeInfo.h"
22 #include "clang/Sema/SemaLambda.h"
23 #include "llvm/ADT/STLExtras.h"
24 using namespace clang;
25 using namespace sema;
26 
27 /// Examines the FunctionScopeInfo stack to determine the nearest
28 /// enclosing lambda (to the current lambda) that is 'capture-ready' for
29 /// the variable referenced in the current lambda (i.e. \p VarToCapture).
30 /// If successful, returns the index into Sema's FunctionScopeInfo stack
31 /// of the capture-ready lambda's LambdaScopeInfo.
32 ///
33 /// Climbs down the stack of lambdas (deepest nested lambda - i.e. current
34 /// lambda - is on top) to determine the index of the nearest enclosing/outer
35 /// lambda that is ready to capture the \p VarToCapture being referenced in
36 /// the current lambda.
37 /// As we climb down the stack, we want the index of the first such lambda -
38 /// that is the lambda with the highest index that is 'capture-ready'.
39 ///
40 /// A lambda 'L' is capture-ready for 'V' (var or this) if:
41 /// - its enclosing context is non-dependent
42 /// - and if the chain of lambdas between L and the lambda in which
43 /// V is potentially used (i.e. the lambda at the top of the scope info
44 /// stack), can all capture or have already captured V.
45 /// If \p VarToCapture is 'null' then we are trying to capture 'this'.
46 ///
47 /// Note that a lambda that is deemed 'capture-ready' still needs to be checked
48 /// for whether it is 'capture-capable' (see
49 /// getStackIndexOfNearestEnclosingCaptureCapableLambda), before it can truly
50 /// capture.
51 ///
52 /// \param FunctionScopes - Sema's stack of nested FunctionScopeInfo's (which a
53 /// LambdaScopeInfo inherits from). The current/deepest/innermost lambda
54 /// is at the top of the stack and has the highest index.
55 /// \param VarToCapture - the variable to capture. If NULL, capture 'this'.
56 ///
57 /// \returns An Optional<unsigned> Index that if evaluates to 'true' contains
58 /// the index (into Sema's FunctionScopeInfo stack) of the innermost lambda
59 /// which is capture-ready. If the return value evaluates to 'false' then
60 /// no lambda is capture-ready for \p VarToCapture.
61 
62 static inline Optional<unsigned>
65  VarDecl *VarToCapture) {
66  // Label failure to capture.
67  const Optional<unsigned> NoLambdaIsCaptureReady;
68 
69  // Ignore all inner captured regions.
70  unsigned CurScopeIndex = FunctionScopes.size() - 1;
71  while (CurScopeIndex > 0 && isa<clang::sema::CapturedRegionScopeInfo>(
72  FunctionScopes[CurScopeIndex]))
73  --CurScopeIndex;
74  assert(
75  isa<clang::sema::LambdaScopeInfo>(FunctionScopes[CurScopeIndex]) &&
76  "The function on the top of sema's function-info stack must be a lambda");
77 
78  // If VarToCapture is null, we are attempting to capture 'this'.
79  const bool IsCapturingThis = !VarToCapture;
80  const bool IsCapturingVariable = !IsCapturingThis;
81 
82  // Start with the current lambda at the top of the stack (highest index).
83  DeclContext *EnclosingDC =
84  cast<sema::LambdaScopeInfo>(FunctionScopes[CurScopeIndex])->CallOperator;
85 
86  do {
87  const clang::sema::LambdaScopeInfo *LSI =
88  cast<sema::LambdaScopeInfo>(FunctionScopes[CurScopeIndex]);
89  // IF we have climbed down to an intervening enclosing lambda that contains
90  // the variable declaration - it obviously can/must not capture the
91  // variable.
92  // Since its enclosing DC is dependent, all the lambdas between it and the
93  // innermost nested lambda are dependent (otherwise we wouldn't have
94  // arrived here) - so we don't yet have a lambda that can capture the
95  // variable.
96  if (IsCapturingVariable &&
97  VarToCapture->getDeclContext()->Equals(EnclosingDC))
98  return NoLambdaIsCaptureReady;
99 
100  // For an enclosing lambda to be capture ready for an entity, all
101  // intervening lambda's have to be able to capture that entity. If even
102  // one of the intervening lambda's is not capable of capturing the entity
103  // then no enclosing lambda can ever capture that entity.
104  // For e.g.
105  // const int x = 10;
106  // [=](auto a) { #1
107  // [](auto b) { #2 <-- an intervening lambda that can never capture 'x'
108  // [=](auto c) { #3
109  // f(x, c); <-- can not lead to x's speculative capture by #1 or #2
110  // }; }; };
111  // If they do not have a default implicit capture, check to see
112  // if the entity has already been explicitly captured.
113  // If even a single dependent enclosing lambda lacks the capability
114  // to ever capture this variable, there is no further enclosing
115  // non-dependent lambda that can capture this variable.
117  if (IsCapturingVariable && !LSI->isCaptured(VarToCapture))
118  return NoLambdaIsCaptureReady;
119  if (IsCapturingThis && !LSI->isCXXThisCaptured())
120  return NoLambdaIsCaptureReady;
121  }
122  EnclosingDC = getLambdaAwareParentOfDeclContext(EnclosingDC);
123 
124  assert(CurScopeIndex);
125  --CurScopeIndex;
126  } while (!EnclosingDC->isTranslationUnit() &&
127  EnclosingDC->isDependentContext() &&
128  isLambdaCallOperator(EnclosingDC));
129 
130  assert(CurScopeIndex < (FunctionScopes.size() - 1));
131  // If the enclosingDC is not dependent, then the immediately nested lambda
132  // (one index above) is capture-ready.
133  if (!EnclosingDC->isDependentContext())
134  return CurScopeIndex + 1;
135  return NoLambdaIsCaptureReady;
136 }
137 
138 /// Examines the FunctionScopeInfo stack to determine the nearest
139 /// enclosing lambda (to the current lambda) that is 'capture-capable' for
140 /// the variable referenced in the current lambda (i.e. \p VarToCapture).
141 /// If successful, returns the index into Sema's FunctionScopeInfo stack
142 /// of the capture-capable lambda's LambdaScopeInfo.
143 ///
144 /// Given the current stack of lambdas being processed by Sema and
145 /// the variable of interest, to identify the nearest enclosing lambda (to the
146 /// current lambda at the top of the stack) that can truly capture
147 /// a variable, it has to have the following two properties:
148 /// a) 'capture-ready' - be the innermost lambda that is 'capture-ready':
149 /// - climb down the stack (i.e. starting from the innermost and examining
150 /// each outer lambda step by step) checking if each enclosing
151 /// lambda can either implicitly or explicitly capture the variable.
152 /// Record the first such lambda that is enclosed in a non-dependent
153 /// context. If no such lambda currently exists return failure.
154 /// b) 'capture-capable' - make sure the 'capture-ready' lambda can truly
155 /// capture the variable by checking all its enclosing lambdas:
156 /// - check if all outer lambdas enclosing the 'capture-ready' lambda
157 /// identified above in 'a' can also capture the variable (this is done
158 /// via tryCaptureVariable for variables and CheckCXXThisCapture for
159 /// 'this' by passing in the index of the Lambda identified in step 'a')
160 ///
161 /// \param FunctionScopes - Sema's stack of nested FunctionScopeInfo's (which a
162 /// LambdaScopeInfo inherits from). The current/deepest/innermost lambda
163 /// is at the top of the stack.
164 ///
165 /// \param VarToCapture - the variable to capture. If NULL, capture 'this'.
166 ///
167 ///
168 /// \returns An Optional<unsigned> Index that if evaluates to 'true' contains
169 /// the index (into Sema's FunctionScopeInfo stack) of the innermost lambda
170 /// which is capture-capable. If the return value evaluates to 'false' then
171 /// no lambda is capture-capable for \p VarToCapture.
172 
175  VarDecl *VarToCapture, Sema &S) {
176 
177  const Optional<unsigned> NoLambdaIsCaptureCapable;
178 
179  const Optional<unsigned> OptionalStackIndex =
181  VarToCapture);
182  if (!OptionalStackIndex)
183  return NoLambdaIsCaptureCapable;
184 
185  const unsigned IndexOfCaptureReadyLambda = OptionalStackIndex.getValue();
186  assert(((IndexOfCaptureReadyLambda != (FunctionScopes.size() - 1)) ||
187  S.getCurGenericLambda()) &&
188  "The capture ready lambda for a potential capture can only be the "
189  "current lambda if it is a generic lambda");
190 
191  const sema::LambdaScopeInfo *const CaptureReadyLambdaLSI =
192  cast<sema::LambdaScopeInfo>(FunctionScopes[IndexOfCaptureReadyLambda]);
193 
194  // If VarToCapture is null, we are attempting to capture 'this'
195  const bool IsCapturingThis = !VarToCapture;
196  const bool IsCapturingVariable = !IsCapturingThis;
197 
198  if (IsCapturingVariable) {
199  // Check if the capture-ready lambda can truly capture the variable, by
200  // checking whether all enclosing lambdas of the capture-ready lambda allow
201  // the capture - i.e. make sure it is capture-capable.
202  QualType CaptureType, DeclRefType;
203  const bool CanCaptureVariable =
204  !S.tryCaptureVariable(VarToCapture,
205  /*ExprVarIsUsedInLoc*/ SourceLocation(),
207  /*EllipsisLoc*/ SourceLocation(),
208  /*BuildAndDiagnose*/ false, CaptureType,
209  DeclRefType, &IndexOfCaptureReadyLambda);
210  if (!CanCaptureVariable)
211  return NoLambdaIsCaptureCapable;
212  } else {
213  // Check if the capture-ready lambda can truly capture 'this' by checking
214  // whether all enclosing lambdas of the capture-ready lambda can capture
215  // 'this'.
216  const bool CanCaptureThis =
218  CaptureReadyLambdaLSI->PotentialThisCaptureLocation,
219  /*Explicit*/ false, /*BuildAndDiagnose*/ false,
220  &IndexOfCaptureReadyLambda);
221  if (!CanCaptureThis)
222  return NoLambdaIsCaptureCapable;
223  }
224  return IndexOfCaptureReadyLambda;
225 }
226 
227 static inline TemplateParameterList *
229  if (!LSI->GLTemplateParameterList && !LSI->TemplateParams.empty()) {
231  SemaRef.Context,
232  /*Template kw loc*/ SourceLocation(),
233  /*L angle loc*/ LSI->ExplicitTemplateParamsRange.getBegin(),
234  LSI->TemplateParams,
235  /*R angle loc*/LSI->ExplicitTemplateParamsRange.getEnd(),
236  nullptr);
237  }
238  return LSI->GLTemplateParameterList;
239 }
240 
242  TypeSourceInfo *Info,
243  bool KnownDependent,
244  LambdaCaptureDefault CaptureDefault) {
245  DeclContext *DC = CurContext;
246  while (!(DC->isFunctionOrMethod() || DC->isRecord() || DC->isFileContext()))
247  DC = DC->getParent();
248  bool IsGenericLambda = getGenericLambdaTemplateParameterList(getCurLambda(),
249  *this);
250  // Start constructing the lambda class.
251  CXXRecordDecl *Class = CXXRecordDecl::CreateLambda(Context, DC, Info,
252  IntroducerRange.getBegin(),
253  KnownDependent,
254  IsGenericLambda,
255  CaptureDefault);
256  DC->addDecl(Class);
257 
258  return Class;
259 }
260 
261 /// Determine whether the given context is or is enclosed in an inline
262 /// function.
263 static bool isInInlineFunction(const DeclContext *DC) {
264  while (!DC->isFileContext()) {
265  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(DC))
266  if (FD->isInlined())
267  return true;
268 
269  DC = DC->getLexicalParent();
270  }
271 
272  return false;
273 }
274 
275 std::tuple<MangleNumberingContext *, Decl *>
277  // Compute the context for allocating mangling numbers in the current
278  // expression, if the ABI requires them.
279  Decl *ManglingContextDecl = ExprEvalContexts.back().ManglingContextDecl;
280 
281  enum ContextKind {
282  Normal,
283  DefaultArgument,
284  DataMember,
285  StaticDataMember,
286  InlineVariable,
287  VariableTemplate
288  } Kind = Normal;
289 
290  // Default arguments of member function parameters that appear in a class
291  // definition, as well as the initializers of data members, receive special
292  // treatment. Identify them.
293  if (ManglingContextDecl) {
294  if (ParmVarDecl *Param = dyn_cast<ParmVarDecl>(ManglingContextDecl)) {
295  if (const DeclContext *LexicalDC
296  = Param->getDeclContext()->getLexicalParent())
297  if (LexicalDC->isRecord())
298  Kind = DefaultArgument;
299  } else if (VarDecl *Var = dyn_cast<VarDecl>(ManglingContextDecl)) {
300  if (Var->getDeclContext()->isRecord())
301  Kind = StaticDataMember;
302  else if (Var->getMostRecentDecl()->isInline())
303  Kind = InlineVariable;
304  else if (Var->getDescribedVarTemplate())
305  Kind = VariableTemplate;
306  else if (auto *VTS = dyn_cast<VarTemplateSpecializationDecl>(Var)) {
307  if (!VTS->isExplicitSpecialization())
308  Kind = VariableTemplate;
309  }
310  } else if (isa<FieldDecl>(ManglingContextDecl)) {
311  Kind = DataMember;
312  }
313  }
314 
315  // Itanium ABI [5.1.7]:
316  // In the following contexts [...] the one-definition rule requires closure
317  // types in different translation units to "correspond":
318  bool IsInNonspecializedTemplate =
319  inTemplateInstantiation() || CurContext->isDependentContext();
320  switch (Kind) {
321  case Normal: {
322  // -- the bodies of non-exported nonspecialized template functions
323  // -- the bodies of inline functions
324  if ((IsInNonspecializedTemplate &&
325  !(ManglingContextDecl && isa<ParmVarDecl>(ManglingContextDecl))) ||
326  isInInlineFunction(CurContext)) {
327  while (auto *CD = dyn_cast<CapturedDecl>(DC))
328  DC = CD->getParent();
329  return std::make_tuple(&Context.getManglingNumberContext(DC), nullptr);
330  }
331 
332  return std::make_tuple(nullptr, nullptr);
333  }
334 
335  case StaticDataMember:
336  // -- the initializers of nonspecialized static members of template classes
337  if (!IsInNonspecializedTemplate)
338  return std::make_tuple(nullptr, ManglingContextDecl);
339  // Fall through to get the current context.
340  LLVM_FALLTHROUGH;
341 
342  case DataMember:
343  // -- the in-class initializers of class members
344  case DefaultArgument:
345  // -- default arguments appearing in class definitions
346  case InlineVariable:
347  // -- the initializers of inline variables
348  case VariableTemplate:
349  // -- the initializers of templated variables
350  return std::make_tuple(
352  ManglingContextDecl),
353  ManglingContextDecl);
354  }
355 
356  llvm_unreachable("unexpected context");
357 }
358 
360  SourceRange IntroducerRange,
361  TypeSourceInfo *MethodTypeInfo,
362  SourceLocation EndLoc,
364  ConstexprSpecKind ConstexprKind) {
365  QualType MethodType = MethodTypeInfo->getType();
366  TemplateParameterList *TemplateParams =
367  getGenericLambdaTemplateParameterList(getCurLambda(), *this);
368  // If a lambda appears in a dependent context or is a generic lambda (has
369  // template parameters) and has an 'auto' return type, deduce it to a
370  // dependent type.
371  if (Class->isDependentContext() || TemplateParams) {
372  const FunctionProtoType *FPT = MethodType->castAs<FunctionProtoType>();
373  QualType Result = FPT->getReturnType();
374  if (Result->isUndeducedType()) {
375  Result = SubstAutoType(Result, Context.DependentTy);
376  MethodType = Context.getFunctionType(Result, FPT->getParamTypes(),
377  FPT->getExtProtoInfo());
378  }
379  }
380 
381  // C++11 [expr.prim.lambda]p5:
382  // The closure type for a lambda-expression has a public inline function
383  // call operator (13.5.4) whose parameters and return type are described by
384  // the lambda-expression's parameter-declaration-clause and
385  // trailing-return-type respectively.
386  DeclarationName MethodName
387  = Context.DeclarationNames.getCXXOperatorName(OO_Call);
388  DeclarationNameLoc MethodNameLoc;
389  MethodNameLoc.CXXOperatorName.BeginOpNameLoc
390  = IntroducerRange.getBegin().getRawEncoding();
391  MethodNameLoc.CXXOperatorName.EndOpNameLoc
392  = IntroducerRange.getEnd().getRawEncoding();
394  Context, Class, EndLoc,
395  DeclarationNameInfo(MethodName, IntroducerRange.getBegin(),
396  MethodNameLoc),
397  MethodType, MethodTypeInfo, SC_None,
398  /*isInline=*/true, ConstexprKind, EndLoc);
399  Method->setAccess(AS_public);
400  if (!TemplateParams)
401  Class->addDecl(Method);
402 
403  // Temporarily set the lexical declaration context to the current
404  // context, so that the Scope stack matches the lexical nesting.
405  Method->setLexicalDeclContext(CurContext);
406  // Create a function template if we have a template parameter list
407  FunctionTemplateDecl *const TemplateMethod = TemplateParams ?
408  FunctionTemplateDecl::Create(Context, Class,
409  Method->getLocation(), MethodName,
410  TemplateParams,
411  Method) : nullptr;
412  if (TemplateMethod) {
413  TemplateMethod->setAccess(AS_public);
414  Method->setDescribedFunctionTemplate(TemplateMethod);
415  Class->addDecl(TemplateMethod);
416  TemplateMethod->setLexicalDeclContext(CurContext);
417  }
418 
419  // Add parameters.
420  if (!Params.empty()) {
421  Method->setParams(Params);
422  CheckParmsForFunctionDef(Params,
423  /*CheckParameterNames=*/false);
424 
425  for (auto P : Method->parameters())
426  P->setOwningFunction(Method);
427  }
428 
429  return Method;
430 }
431 
433  CXXRecordDecl *Class, CXXMethodDecl *Method,
434  Optional<std::tuple<unsigned, bool, Decl *>> Mangling) {
435  if (Mangling) {
436  unsigned ManglingNumber;
437  bool HasKnownInternalLinkage;
438  Decl *ManglingContextDecl;
439  std::tie(ManglingNumber, HasKnownInternalLinkage, ManglingContextDecl) =
440  Mangling.getValue();
441  Class->setLambdaMangling(ManglingNumber, ManglingContextDecl,
442  HasKnownInternalLinkage);
443  return;
444  }
445 
446  auto getMangleNumberingContext =
447  [this](CXXRecordDecl *Class,
448  Decl *ManglingContextDecl) -> MangleNumberingContext * {
449  // Get mangle numbering context if there's any extra decl context.
450  if (ManglingContextDecl)
451  return &Context.getManglingNumberContext(
452  ASTContext::NeedExtraManglingDecl, ManglingContextDecl);
453  // Otherwise, from that lambda's decl context.
454  auto DC = Class->getDeclContext();
455  while (auto *CD = dyn_cast<CapturedDecl>(DC))
456  DC = CD->getParent();
457  return &Context.getManglingNumberContext(DC);
458  };
459 
461  Decl *ManglingContextDecl;
462  std::tie(MCtx, ManglingContextDecl) =
463  getCurrentMangleNumberContext(Class->getDeclContext());
464  bool HasKnownInternalLinkage = false;
465  if (!MCtx && getLangOpts().CUDA) {
466  // Force lambda numbering in CUDA/HIP as we need to name lambdas following
467  // ODR. Both device- and host-compilation need to have a consistent naming
468  // on kernel functions. As lambdas are potential part of these `__global__`
469  // function names, they needs numbering following ODR.
470  MCtx = getMangleNumberingContext(Class, ManglingContextDecl);
471  assert(MCtx && "Retrieving mangle numbering context failed!");
472  HasKnownInternalLinkage = true;
473  }
474  if (MCtx) {
475  unsigned ManglingNumber = MCtx->getManglingNumber(Method);
476  Class->setLambdaMangling(ManglingNumber, ManglingContextDecl,
477  HasKnownInternalLinkage);
478  }
479 }
480 
482  CXXMethodDecl *CallOperator,
483  SourceRange IntroducerRange,
484  LambdaCaptureDefault CaptureDefault,
485  SourceLocation CaptureDefaultLoc,
486  bool ExplicitParams,
487  bool ExplicitResultType,
488  bool Mutable) {
489  LSI->CallOperator = CallOperator;
490  CXXRecordDecl *LambdaClass = CallOperator->getParent();
491  LSI->Lambda = LambdaClass;
492  if (CaptureDefault == LCD_ByCopy)
494  else if (CaptureDefault == LCD_ByRef)
496  LSI->CaptureDefaultLoc = CaptureDefaultLoc;
497  LSI->IntroducerRange = IntroducerRange;
498  LSI->ExplicitParams = ExplicitParams;
499  LSI->Mutable = Mutable;
500 
501  if (ExplicitResultType) {
502  LSI->ReturnType = CallOperator->getReturnType();
503 
504  if (!LSI->ReturnType->isDependentType() &&
505  !LSI->ReturnType->isVoidType()) {
506  if (RequireCompleteType(CallOperator->getBeginLoc(), LSI->ReturnType,
507  diag::err_lambda_incomplete_result)) {
508  // Do nothing.
509  }
510  }
511  } else {
512  LSI->HasImplicitReturnType = true;
513  }
514 }
515 
518 }
519 
521  ArrayRef<NamedDecl *> TParams,
522  SourceLocation RAngleLoc) {
523  LambdaScopeInfo *LSI = getCurLambda();
524  assert(LSI && "Expected a lambda scope");
525  assert(LSI->NumExplicitTemplateParams == 0 &&
526  "Already acted on explicit template parameters");
527  assert(LSI->TemplateParams.empty() &&
528  "Explicit template parameters should come "
529  "before invented (auto) ones");
530  assert(!TParams.empty() &&
531  "No template parameters to act on");
532  LSI->TemplateParams.append(TParams.begin(), TParams.end());
533  LSI->NumExplicitTemplateParams = TParams.size();
534  LSI->ExplicitTemplateParamsRange = {LAngleLoc, RAngleLoc};
535 }
536 
539  CXXMethodDecl *CallOperator, Scope *CurScope) {
540  // Introduce our parameters into the function scope
541  for (unsigned p = 0, NumParams = CallOperator->getNumParams();
542  p < NumParams; ++p) {
543  ParmVarDecl *Param = CallOperator->getParamDecl(p);
544 
545  // If this has an identifier, add it to the scope stack.
546  if (CurScope && Param->getIdentifier()) {
547  bool Error = false;
548  // Resolution of CWG 2211 in C++17 renders shadowing ill-formed, but we
549  // retroactively apply it.
550  for (const auto &Capture : Captures) {
551  if (Capture.Id == Param->getIdentifier()) {
552  Error = true;
553  Diag(Param->getLocation(), diag::err_parameter_shadow_capture);
554  Diag(Capture.Loc, diag::note_var_explicitly_captured_here)
555  << Capture.Id << true;
556  }
557  }
558  if (!Error)
559  CheckShadow(CurScope, Param);
560 
561  PushOnScopeChains(Param, CurScope);
562  }
563  }
564 }
565 
566 /// If this expression is an enumerator-like expression of some type
567 /// T, return the type T; otherwise, return null.
568 ///
569 /// Pointer comparisons on the result here should always work because
570 /// it's derived from either the parent of an EnumConstantDecl
571 /// (i.e. the definition) or the declaration returned by
572 /// EnumType::getDecl() (i.e. the definition).
574  // An expression is an enumerator-like expression of type T if,
575  // ignoring parens and parens-like expressions:
576  E = E->IgnoreParens();
577 
578  // - it is an enumerator whose enum type is T or
579  if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) {
580  if (EnumConstantDecl *D
581  = dyn_cast<EnumConstantDecl>(DRE->getDecl())) {
582  return cast<EnumDecl>(D->getDeclContext());
583  }
584  return nullptr;
585  }
586 
587  // - it is a comma expression whose RHS is an enumerator-like
588  // expression of type T or
589  if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) {
590  if (BO->getOpcode() == BO_Comma)
591  return findEnumForBlockReturn(BO->getRHS());
592  return nullptr;
593  }
594 
595  // - it is a statement-expression whose value expression is an
596  // enumerator-like expression of type T or
597  if (StmtExpr *SE = dyn_cast<StmtExpr>(E)) {
598  if (Expr *last = dyn_cast_or_null<Expr>(SE->getSubStmt()->body_back()))
599  return findEnumForBlockReturn(last);
600  return nullptr;
601  }
602 
603  // - it is a ternary conditional operator (not the GNU ?:
604  // extension) whose second and third operands are
605  // enumerator-like expressions of type T or
606  if (ConditionalOperator *CO = dyn_cast<ConditionalOperator>(E)) {
607  if (EnumDecl *ED = findEnumForBlockReturn(CO->getTrueExpr()))
608  if (ED == findEnumForBlockReturn(CO->getFalseExpr()))
609  return ED;
610  return nullptr;
611  }
612 
613  // (implicitly:)
614  // - it is an implicit integral conversion applied to an
615  // enumerator-like expression of type T or
616  if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) {
617  // We can sometimes see integral conversions in valid
618  // enumerator-like expressions.
619  if (ICE->getCastKind() == CK_IntegralCast)
620  return findEnumForBlockReturn(ICE->getSubExpr());
621 
622  // Otherwise, just rely on the type.
623  }
624 
625  // - it is an expression of that formal enum type.
626  if (const EnumType *ET = E->getType()->getAs<EnumType>()) {
627  return ET->getDecl();
628  }
629 
630  // Otherwise, nope.
631  return nullptr;
632 }
633 
634 /// Attempt to find a type T for which the returned expression of the
635 /// given statement is an enumerator-like expression of that type.
637  if (Expr *retValue = ret->getRetValue())
638  return findEnumForBlockReturn(retValue);
639  return nullptr;
640 }
641 
642 /// Attempt to find a common type T for which all of the returned
643 /// expressions in a block are enumerator-like expressions of that
644 /// type.
646  ArrayRef<ReturnStmt*>::iterator i = returns.begin(), e = returns.end();
647 
648  // Try to find one for the first return.
650  if (!ED) return nullptr;
651 
652  // Check that the rest of the returns have the same enum.
653  for (++i; i != e; ++i) {
654  if (findEnumForBlockReturn(*i) != ED)
655  return nullptr;
656  }
657 
658  // Never infer an anonymous enum type.
659  if (!ED->hasNameForLinkage()) return nullptr;
660 
661  return ED;
662 }
663 
664 /// Adjust the given return statements so that they formally return
665 /// the given type. It should require, at most, an IntegralCast.
667  QualType returnType) {
669  i = returns.begin(), e = returns.end(); i != e; ++i) {
670  ReturnStmt *ret = *i;
671  Expr *retValue = ret->getRetValue();
672  if (S.Context.hasSameType(retValue->getType(), returnType))
673  continue;
674 
675  // Right now we only support integral fixup casts.
676  assert(returnType->isIntegralOrUnscopedEnumerationType());
677  assert(retValue->getType()->isIntegralOrUnscopedEnumerationType());
678 
679  ExprWithCleanups *cleanups = dyn_cast<ExprWithCleanups>(retValue);
680 
681  Expr *E = (cleanups ? cleanups->getSubExpr() : retValue);
682  E = ImplicitCastExpr::Create(S.Context, returnType, CK_IntegralCast,
683  E, /*base path*/ nullptr, VK_RValue);
684  if (cleanups) {
685  cleanups->setSubExpr(E);
686  } else {
687  ret->setRetValue(E);
688  }
689  }
690 }
691 
693  assert(CSI.HasImplicitReturnType);
694  // If it was ever a placeholder, it had to been deduced to DependentTy.
695  assert(CSI.ReturnType.isNull() || !CSI.ReturnType->isUndeducedType());
696  assert((!isa<LambdaScopeInfo>(CSI) || !getLangOpts().CPlusPlus14) &&
697  "lambda expressions use auto deduction in C++14 onwards");
698 
699  // C++ core issue 975:
700  // If a lambda-expression does not include a trailing-return-type,
701  // it is as if the trailing-return-type denotes the following type:
702  // - if there are no return statements in the compound-statement,
703  // or all return statements return either an expression of type
704  // void or no expression or braced-init-list, the type void;
705  // - otherwise, if all return statements return an expression
706  // and the types of the returned expressions after
707  // lvalue-to-rvalue conversion (4.1 [conv.lval]),
708  // array-to-pointer conversion (4.2 [conv.array]), and
709  // function-to-pointer conversion (4.3 [conv.func]) are the
710  // same, that common type;
711  // - otherwise, the program is ill-formed.
712  //
713  // C++ core issue 1048 additionally removes top-level cv-qualifiers
714  // from the types of returned expressions to match the C++14 auto
715  // deduction rules.
716  //
717  // In addition, in blocks in non-C++ modes, if all of the return
718  // statements are enumerator-like expressions of some type T, where
719  // T has a name for linkage, then we infer the return type of the
720  // block to be that type.
721 
722  // First case: no return statements, implicit void return type.
723  ASTContext &Ctx = getASTContext();
724  if (CSI.Returns.empty()) {
725  // It's possible there were simply no /valid/ return statements.
726  // In this case, the first one we found may have at least given us a type.
727  if (CSI.ReturnType.isNull())
728  CSI.ReturnType = Ctx.VoidTy;
729  return;
730  }
731 
732  // Second case: at least one return statement has dependent type.
733  // Delay type checking until instantiation.
734  assert(!CSI.ReturnType.isNull() && "We should have a tentative return type.");
735  if (CSI.ReturnType->isDependentType())
736  return;
737 
738  // Try to apply the enum-fuzz rule.
739  if (!getLangOpts().CPlusPlus) {
740  assert(isa<BlockScopeInfo>(CSI));
742  if (ED) {
743  CSI.ReturnType = Context.getTypeDeclType(ED);
745  return;
746  }
747  }
748 
749  // Third case: only one return statement. Don't bother doing extra work!
750  if (CSI.Returns.size() == 1)
751  return;
752 
753  // General case: many return statements.
754  // Check that they all have compatible return types.
755 
756  // We require the return types to strictly match here.
757  // Note that we've already done the required promotions as part of
758  // processing the return statement.
759  for (const ReturnStmt *RS : CSI.Returns) {
760  const Expr *RetE = RS->getRetValue();
761 
762  QualType ReturnType =
763  (RetE ? RetE->getType() : Context.VoidTy).getUnqualifiedType();
764  if (Context.getCanonicalFunctionResultType(ReturnType) ==
766  // Use the return type with the strictest possible nullability annotation.
767  auto RetTyNullability = ReturnType->getNullability(Ctx);
768  auto BlockNullability = CSI.ReturnType->getNullability(Ctx);
769  if (BlockNullability &&
770  (!RetTyNullability ||
771  hasWeakerNullability(*RetTyNullability, *BlockNullability)))
772  CSI.ReturnType = ReturnType;
773  continue;
774  }
775 
776  // FIXME: This is a poor diagnostic for ReturnStmts without expressions.
777  // TODO: It's possible that the *first* return is the divergent one.
778  Diag(RS->getBeginLoc(),
779  diag::err_typecheck_missing_return_type_incompatible)
780  << ReturnType << CSI.ReturnType << isa<LambdaScopeInfo>(CSI);
781  // Continue iterating so that we keep emitting diagnostics.
782  }
783 }
784 
786  SourceLocation Loc, bool ByRef, SourceLocation EllipsisLoc,
787  Optional<unsigned> NumExpansions, IdentifierInfo *Id, bool IsDirectInit,
788  Expr *&Init) {
789  // Create an 'auto' or 'auto&' TypeSourceInfo that we can use to
790  // deduce against.
791  QualType DeductType = Context.getAutoDeductType();
792  TypeLocBuilder TLB;
793  TLB.pushTypeSpec(DeductType).setNameLoc(Loc);
794  if (ByRef) {
795  DeductType = BuildReferenceType(DeductType, true, Loc, Id);
796  assert(!DeductType.isNull() && "can't build reference to auto");
797  TLB.push<ReferenceTypeLoc>(DeductType).setSigilLoc(Loc);
798  }
799  if (EllipsisLoc.isValid()) {
800  if (Init->containsUnexpandedParameterPack()) {
801  Diag(EllipsisLoc, getLangOpts().CPlusPlus2a
802  ? diag::warn_cxx17_compat_init_capture_pack
803  : diag::ext_init_capture_pack);
804  DeductType = Context.getPackExpansionType(DeductType, NumExpansions);
805  TLB.push<PackExpansionTypeLoc>(DeductType).setEllipsisLoc(EllipsisLoc);
806  } else {
807  // Just ignore the ellipsis for now and form a non-pack variable. We'll
808  // diagnose this later when we try to capture it.
809  }
810  }
811  TypeSourceInfo *TSI = TLB.getTypeSourceInfo(Context, DeductType);
812 
813  // Deduce the type of the init capture.
814  QualType DeducedType = deduceVarTypeFromInitializer(
815  /*VarDecl*/nullptr, DeclarationName(Id), DeductType, TSI,
816  SourceRange(Loc, Loc), IsDirectInit, Init);
817  if (DeducedType.isNull())
818  return QualType();
819 
820  // Are we a non-list direct initialization?
821  ParenListExpr *CXXDirectInit = dyn_cast<ParenListExpr>(Init);
822 
823  // Perform initialization analysis and ensure any implicit conversions
824  // (such as lvalue-to-rvalue) are enforced.
825  InitializedEntity Entity =
826  InitializedEntity::InitializeLambdaCapture(Id, DeducedType, Loc);
828  IsDirectInit
829  ? (CXXDirectInit ? InitializationKind::CreateDirect(
830  Loc, Init->getBeginLoc(), Init->getEndLoc())
833 
834  MultiExprArg Args = Init;
835  if (CXXDirectInit)
836  Args =
837  MultiExprArg(CXXDirectInit->getExprs(), CXXDirectInit->getNumExprs());
838  QualType DclT;
839  InitializationSequence InitSeq(*this, Entity, Kind, Args);
840  ExprResult Result = InitSeq.Perform(*this, Entity, Kind, Args, &DclT);
841 
842  if (Result.isInvalid())
843  return QualType();
844 
845  Init = Result.getAs<Expr>();
846  return DeducedType;
847 }
848 
850  QualType InitCaptureType,
851  SourceLocation EllipsisLoc,
853  unsigned InitStyle, Expr *Init) {
854  // FIXME: Retain the TypeSourceInfo from buildLambdaInitCaptureInitialization
855  // rather than reconstructing it here.
856  TypeSourceInfo *TSI = Context.getTrivialTypeSourceInfo(InitCaptureType, Loc);
857  if (auto PETL = TSI->getTypeLoc().getAs<PackExpansionTypeLoc>())
858  PETL.setEllipsisLoc(EllipsisLoc);
859 
860  // Create a dummy variable representing the init-capture. This is not actually
861  // used as a variable, and only exists as a way to name and refer to the
862  // init-capture.
863  // FIXME: Pass in separate source locations for '&' and identifier.
864  VarDecl *NewVD = VarDecl::Create(Context, CurContext, Loc,
865  Loc, Id, InitCaptureType, TSI, SC_Auto);
866  NewVD->setInitCapture(true);
867  NewVD->setReferenced(true);
868  // FIXME: Pass in a VarDecl::InitializationStyle.
869  NewVD->setInitStyle(static_cast<VarDecl::InitializationStyle>(InitStyle));
870  NewVD->markUsed(Context);
871  NewVD->setInit(Init);
872  if (NewVD->isParameterPack())
873  getCurLambda()->LocalPacks.push_back(NewVD);
874  return NewVD;
875 }
876 
878  assert(Var->isInitCapture() && "init capture flag should be set");
879  LSI->addCapture(Var, /*isBlock*/false, Var->getType()->isReferenceType(),
880  /*isNested*/false, Var->getLocation(), SourceLocation(),
881  Var->getType(), /*Invalid*/false);
882 }
883 
885  Declarator &ParamInfo,
886  Scope *CurScope) {
887  LambdaScopeInfo *const LSI = getCurLambda();
888  assert(LSI && "LambdaScopeInfo should be on stack!");
889 
890  // Determine if we're within a context where we know that the lambda will
891  // be dependent, because there are template parameters in scope.
892  bool KnownDependent;
893  if (LSI->NumExplicitTemplateParams > 0) {
894  auto *TemplateParamScope = CurScope->getTemplateParamParent();
895  assert(TemplateParamScope &&
896  "Lambda with explicit template param list should establish a "
897  "template param scope");
898  assert(TemplateParamScope->getParent());
899  KnownDependent = TemplateParamScope->getParent()
900  ->getTemplateParamParent() != nullptr;
901  } else {
902  KnownDependent = CurScope->getTemplateParamParent() != nullptr;
903  }
904 
905  // Determine the signature of the call operator.
906  TypeSourceInfo *MethodTyInfo;
907  bool ExplicitParams = true;
908  bool ExplicitResultType = true;
909  bool ContainsUnexpandedParameterPack = false;
910  SourceLocation EndLoc;
912  if (ParamInfo.getNumTypeObjects() == 0) {
913  // C++11 [expr.prim.lambda]p4:
914  // If a lambda-expression does not include a lambda-declarator, it is as
915  // if the lambda-declarator were ().
917  /*IsVariadic=*/false, /*IsCXXMethod=*/true));
918  EPI.HasTrailingReturn = true;
919  EPI.TypeQuals.addConst();
920  // C++1y [expr.prim.lambda]:
921  // The lambda return type is 'auto', which is replaced by the
922  // trailing-return type if provided and/or deduced from 'return'
923  // statements
924  // We don't do this before C++1y, because we don't support deduced return
925  // types there.
926  QualType DefaultTypeForNoTrailingReturn =
927  getLangOpts().CPlusPlus14 ? Context.getAutoDeductType()
928  : Context.DependentTy;
929  QualType MethodTy =
930  Context.getFunctionType(DefaultTypeForNoTrailingReturn, None, EPI);
931  MethodTyInfo = Context.getTrivialTypeSourceInfo(MethodTy);
932  ExplicitParams = false;
933  ExplicitResultType = false;
934  EndLoc = Intro.Range.getEnd();
935  } else {
936  assert(ParamInfo.isFunctionDeclarator() &&
937  "lambda-declarator is a function");
939 
940  // C++11 [expr.prim.lambda]p5:
941  // This function call operator is declared const (9.3.1) if and only if
942  // the lambda-expression's parameter-declaration-clause is not followed
943  // by mutable. It is neither virtual nor declared volatile. [...]
944  if (!FTI.hasMutableQualifier()) {
946  SourceLocation());
947  }
948 
949  MethodTyInfo = GetTypeForDeclarator(ParamInfo, CurScope);
950  assert(MethodTyInfo && "no type from lambda-declarator");
951  EndLoc = ParamInfo.getSourceRange().getEnd();
952 
953  ExplicitResultType = FTI.hasTrailingReturnType();
954 
955  if (FTIHasNonVoidParameters(FTI)) {
956  Params.reserve(FTI.NumParams);
957  for (unsigned i = 0, e = FTI.NumParams; i != e; ++i)
958  Params.push_back(cast<ParmVarDecl>(FTI.Params[i].Param));
959  }
960 
961  // Check for unexpanded parameter packs in the method type.
962  if (MethodTyInfo->getType()->containsUnexpandedParameterPack())
963  DiagnoseUnexpandedParameterPack(Intro.Range.getBegin(), MethodTyInfo,
964  UPPC_DeclarationType);
965  }
966 
967  CXXRecordDecl *Class = createLambdaClosureType(Intro.Range, MethodTyInfo,
968  KnownDependent, Intro.Default);
969  CXXMethodDecl *Method =
970  startLambdaDefinition(Class, Intro.Range, MethodTyInfo, EndLoc, Params,
971  ParamInfo.getDeclSpec().getConstexprSpecifier());
972  if (ExplicitParams)
973  CheckCXXDefaultArguments(Method);
974 
975  // This represents the function body for the lambda function, check if we
976  // have to apply optnone due to a pragma.
977  AddRangeBasedOptnone(Method);
978 
979  // code_seg attribute on lambda apply to the method.
980  if (Attr *A = getImplicitCodeSegOrSectionAttrForFunction(Method, /*IsDefinition=*/true))
981  Method->addAttr(A);
982 
983  // Attributes on the lambda apply to the method.
984  ProcessDeclAttributes(CurScope, Method, ParamInfo);
985 
986  // CUDA lambdas get implicit attributes based on the scope in which they're
987  // declared.
988  if (getLangOpts().CUDA)
989  CUDASetLambdaAttrs(Method);
990 
991  // Number the lambda for linkage purposes if necessary.
992  handleLambdaNumbering(Class, Method);
993 
994  // Introduce the function call operator as the current declaration context.
995  PushDeclContext(CurScope, Method);
996 
997  // Build the lambda scope.
998  buildLambdaScope(LSI, Method, Intro.Range, Intro.Default, Intro.DefaultLoc,
999  ExplicitParams, ExplicitResultType, !Method->isConst());
1000 
1001  // C++11 [expr.prim.lambda]p9:
1002  // A lambda-expression whose smallest enclosing scope is a block scope is a
1003  // local lambda expression; any other lambda expression shall not have a
1004  // capture-default or simple-capture in its lambda-introducer.
1005  //
1006  // For simple-captures, this is covered by the check below that any named
1007  // entity is a variable that can be captured.
1008  //
1009  // For DR1632, we also allow a capture-default in any context where we can
1010  // odr-use 'this' (in particular, in a default initializer for a non-static
1011  // data member).
1012  if (Intro.Default != LCD_None && !Class->getParent()->isFunctionOrMethod() &&
1013  (getCurrentThisType().isNull() ||
1014  CheckCXXThisCapture(SourceLocation(), /*Explicit*/true,
1015  /*BuildAndDiagnose*/false)))
1016  Diag(Intro.DefaultLoc, diag::err_capture_default_non_local);
1017 
1018  // Distinct capture names, for diagnostics.
1019  llvm::SmallSet<IdentifierInfo*, 8> CaptureNames;
1020 
1021  // Handle explicit captures.
1022  SourceLocation PrevCaptureLoc
1023  = Intro.Default == LCD_None? Intro.Range.getBegin() : Intro.DefaultLoc;
1024  for (auto C = Intro.Captures.begin(), E = Intro.Captures.end(); C != E;
1025  PrevCaptureLoc = C->Loc, ++C) {
1026  if (C->Kind == LCK_This || C->Kind == LCK_StarThis) {
1027  if (C->Kind == LCK_StarThis)
1028  Diag(C->Loc, !getLangOpts().CPlusPlus17
1029  ? diag::ext_star_this_lambda_capture_cxx17
1030  : diag::warn_cxx14_compat_star_this_lambda_capture);
1031 
1032  // C++11 [expr.prim.lambda]p8:
1033  // An identifier or this shall not appear more than once in a
1034  // lambda-capture.
1035  if (LSI->isCXXThisCaptured()) {
1036  Diag(C->Loc, diag::err_capture_more_than_once)
1037  << "'this'" << SourceRange(LSI->getCXXThisCapture().getLocation())
1039  SourceRange(getLocForEndOfToken(PrevCaptureLoc), C->Loc));
1040  continue;
1041  }
1042 
1043  // C++2a [expr.prim.lambda]p8:
1044  // If a lambda-capture includes a capture-default that is =,
1045  // each simple-capture of that lambda-capture shall be of the form
1046  // "&identifier", "this", or "* this". [ Note: The form [&,this] is
1047  // redundant but accepted for compatibility with ISO C++14. --end note ]
1048  if (Intro.Default == LCD_ByCopy && C->Kind != LCK_StarThis)
1049  Diag(C->Loc, !getLangOpts().CPlusPlus2a
1050  ? diag::ext_equals_this_lambda_capture_cxx2a
1051  : diag::warn_cxx17_compat_equals_this_lambda_capture);
1052 
1053  // C++11 [expr.prim.lambda]p12:
1054  // If this is captured by a local lambda expression, its nearest
1055  // enclosing function shall be a non-static member function.
1056  QualType ThisCaptureType = getCurrentThisType();
1057  if (ThisCaptureType.isNull()) {
1058  Diag(C->Loc, diag::err_this_capture) << true;
1059  continue;
1060  }
1061 
1062  CheckCXXThisCapture(C->Loc, /*Explicit=*/true, /*BuildAndDiagnose*/ true,
1063  /*FunctionScopeIndexToStopAtPtr*/ nullptr,
1064  C->Kind == LCK_StarThis);
1065  if (!LSI->Captures.empty())
1066  LSI->ExplicitCaptureRanges[LSI->Captures.size() - 1] = C->ExplicitRange;
1067  continue;
1068  }
1069 
1070  assert(C->Id && "missing identifier for capture");
1071 
1072  if (C->Init.isInvalid())
1073  continue;
1074 
1075  VarDecl *Var = nullptr;
1076  if (C->Init.isUsable()) {
1077  Diag(C->Loc, getLangOpts().CPlusPlus14
1078  ? diag::warn_cxx11_compat_init_capture
1079  : diag::ext_init_capture);
1080 
1081  // If the initializer expression is usable, but the InitCaptureType
1082  // is not, then an error has occurred - so ignore the capture for now.
1083  // for e.g., [n{0}] { }; <-- if no <initializer_list> is included.
1084  // FIXME: we should create the init capture variable and mark it invalid
1085  // in this case.
1086  if (C->InitCaptureType.get().isNull())
1087  continue;
1088 
1089  if (C->Init.get()->containsUnexpandedParameterPack() &&
1090  !C->InitCaptureType.get()->getAs<PackExpansionType>())
1091  DiagnoseUnexpandedParameterPack(C->Init.get(), UPPC_Initializer);
1092 
1093  unsigned InitStyle;
1094  switch (C->InitKind) {
1096  llvm_unreachable("not an init-capture?");
1098  InitStyle = VarDecl::CInit;
1099  break;
1101  InitStyle = VarDecl::CallInit;
1102  break;
1104  InitStyle = VarDecl::ListInit;
1105  break;
1106  }
1107  Var = createLambdaInitCaptureVarDecl(C->Loc, C->InitCaptureType.get(),
1108  C->EllipsisLoc, C->Id, InitStyle,
1109  C->Init.get());
1110  // C++1y [expr.prim.lambda]p11:
1111  // An init-capture behaves as if it declares and explicitly
1112  // captures a variable [...] whose declarative region is the
1113  // lambda-expression's compound-statement
1114  if (Var)
1115  PushOnScopeChains(Var, CurScope, false);
1116  } else {
1117  assert(C->InitKind == LambdaCaptureInitKind::NoInit &&
1118  "init capture has valid but null init?");
1119 
1120  // C++11 [expr.prim.lambda]p8:
1121  // If a lambda-capture includes a capture-default that is &, the
1122  // identifiers in the lambda-capture shall not be preceded by &.
1123  // If a lambda-capture includes a capture-default that is =, [...]
1124  // each identifier it contains shall be preceded by &.
1125  if (C->Kind == LCK_ByRef && Intro.Default == LCD_ByRef) {
1126  Diag(C->Loc, diag::err_reference_capture_with_reference_default)
1128  SourceRange(getLocForEndOfToken(PrevCaptureLoc), C->Loc));
1129  continue;
1130  } else if (C->Kind == LCK_ByCopy && Intro.Default == LCD_ByCopy) {
1131  Diag(C->Loc, diag::err_copy_capture_with_copy_default)
1133  SourceRange(getLocForEndOfToken(PrevCaptureLoc), C->Loc));
1134  continue;
1135  }
1136 
1137  // C++11 [expr.prim.lambda]p10:
1138  // The identifiers in a capture-list are looked up using the usual
1139  // rules for unqualified name lookup (3.4.1)
1140  DeclarationNameInfo Name(C->Id, C->Loc);
1141  LookupResult R(*this, Name, LookupOrdinaryName);
1142  LookupName(R, CurScope);
1143  if (R.isAmbiguous())
1144  continue;
1145  if (R.empty()) {
1146  // FIXME: Disable corrections that would add qualification?
1147  CXXScopeSpec ScopeSpec;
1148  DeclFilterCCC<VarDecl> Validator{};
1149  if (DiagnoseEmptyLookup(CurScope, ScopeSpec, R, Validator))
1150  continue;
1151  }
1152 
1153  Var = R.getAsSingle<VarDecl>();
1154  if (Var && DiagnoseUseOfDecl(Var, C->Loc))
1155  continue;
1156  }
1157 
1158  // C++11 [expr.prim.lambda]p8:
1159  // An identifier or this shall not appear more than once in a
1160  // lambda-capture.
1161  if (!CaptureNames.insert(C->Id).second) {
1162  if (Var && LSI->isCaptured(Var)) {
1163  Diag(C->Loc, diag::err_capture_more_than_once)
1164  << C->Id << SourceRange(LSI->getCapture(Var).getLocation())
1166  SourceRange(getLocForEndOfToken(PrevCaptureLoc), C->Loc));
1167  } else
1168  // Previous capture captured something different (one or both was
1169  // an init-cpature): no fixit.
1170  Diag(C->Loc, diag::err_capture_more_than_once) << C->Id;
1171  continue;
1172  }
1173 
1174  // C++11 [expr.prim.lambda]p10:
1175  // [...] each such lookup shall find a variable with automatic storage
1176  // duration declared in the reaching scope of the local lambda expression.
1177  // Note that the 'reaching scope' check happens in tryCaptureVariable().
1178  if (!Var) {
1179  Diag(C->Loc, diag::err_capture_does_not_name_variable) << C->Id;
1180  continue;
1181  }
1182 
1183  // Ignore invalid decls; they'll just confuse the code later.
1184  if (Var->isInvalidDecl())
1185  continue;
1186 
1187  if (!Var->hasLocalStorage()) {
1188  Diag(C->Loc, diag::err_capture_non_automatic_variable) << C->Id;
1189  Diag(Var->getLocation(), diag::note_previous_decl) << C->Id;
1190  continue;
1191  }
1192 
1193  // C++11 [expr.prim.lambda]p23:
1194  // A capture followed by an ellipsis is a pack expansion (14.5.3).
1195  SourceLocation EllipsisLoc;
1196  if (C->EllipsisLoc.isValid()) {
1197  if (Var->isParameterPack()) {
1198  EllipsisLoc = C->EllipsisLoc;
1199  } else {
1200  Diag(C->EllipsisLoc, diag::err_pack_expansion_without_parameter_packs)
1201  << (C->Init.isUsable() ? C->Init.get()->getSourceRange()
1202  : SourceRange(C->Loc));
1203 
1204  // Just ignore the ellipsis.
1205  }
1206  } else if (Var->isParameterPack()) {
1207  ContainsUnexpandedParameterPack = true;
1208  }
1209 
1210  if (C->Init.isUsable()) {
1211  addInitCapture(LSI, Var);
1212  } else {
1213  TryCaptureKind Kind = C->Kind == LCK_ByRef ? TryCapture_ExplicitByRef :
1214  TryCapture_ExplicitByVal;
1215  tryCaptureVariable(Var, C->Loc, Kind, EllipsisLoc);
1216  }
1217  if (!LSI->Captures.empty())
1218  LSI->ExplicitCaptureRanges[LSI->Captures.size() - 1] = C->ExplicitRange;
1219  }
1220  finishLambdaExplicitCaptures(LSI);
1221 
1222  LSI->ContainsUnexpandedParameterPack |= ContainsUnexpandedParameterPack;
1223 
1224  // Add lambda parameters into scope.
1225  addLambdaParameters(Intro.Captures, Method, CurScope);
1226 
1227  // Enter a new evaluation context to insulate the lambda from any
1228  // cleanups from the enclosing full-expression.
1229  PushExpressionEvaluationContext(
1230  ExpressionEvaluationContext::PotentiallyEvaluated);
1231 }
1232 
1234  bool IsInstantiation) {
1235  LambdaScopeInfo *LSI = cast<LambdaScopeInfo>(FunctionScopes.back());
1236 
1237  // Leave the expression-evaluation context.
1238  DiscardCleanupsInEvaluationContext();
1239  PopExpressionEvaluationContext();
1240 
1241  // Leave the context of the lambda.
1242  if (!IsInstantiation)
1243  PopDeclContext();
1244 
1245  // Finalize the lambda.
1246  CXXRecordDecl *Class = LSI->Lambda;
1247  Class->setInvalidDecl();
1248  SmallVector<Decl*, 4> Fields(Class->fields());
1249  ActOnFields(nullptr, Class->getLocation(), Class, Fields, SourceLocation(),
1251  CheckCompletedCXXClass(Class);
1252 
1253  PopFunctionScopeInfo();
1254 }
1255 
1257  const FunctionProtoType *CallOpProto) {
1258  // The function type inside the pointer type is the same as the call
1259  // operator with some tweaks. The calling convention is the default free
1260  // function convention, and the type qualifications are lost.
1261  const FunctionProtoType::ExtProtoInfo CallOpExtInfo =
1262  CallOpProto->getExtProtoInfo();
1263  FunctionProtoType::ExtProtoInfo InvokerExtInfo = CallOpExtInfo;
1265  CallOpProto->isVariadic(), /*IsCXXMethod=*/false);
1266  InvokerExtInfo.ExtInfo = InvokerExtInfo.ExtInfo.withCallingConv(CC);
1267  InvokerExtInfo.TypeQuals = Qualifiers();
1268  assert(InvokerExtInfo.RefQualifier == RQ_None &&
1269  "Lambda's call operator should not have a reference qualifier");
1270  return Context.getFunctionType(CallOpProto->getReturnType(),
1271  CallOpProto->getParamTypes(), InvokerExtInfo);
1272 }
1273 
1274 /// Add a lambda's conversion to function pointer, as described in
1275 /// C++11 [expr.prim.lambda]p6.
1277  SourceRange IntroducerRange,
1278  CXXRecordDecl *Class,
1279  CXXMethodDecl *CallOperator) {
1280  // This conversion is explicitly disabled if the lambda's function has
1281  // pass_object_size attributes on any of its parameters.
1282  auto HasPassObjectSizeAttr = [](const ParmVarDecl *P) {
1283  return P->hasAttr<PassObjectSizeAttr>();
1284  };
1285  if (llvm::any_of(CallOperator->parameters(), HasPassObjectSizeAttr))
1286  return;
1287 
1288  // Add the conversion to function pointer.
1289  QualType InvokerFunctionTy = S.getLambdaConversionFunctionResultType(
1290  CallOperator->getType()->castAs<FunctionProtoType>());
1291  QualType PtrToFunctionTy = S.Context.getPointerType(InvokerFunctionTy);
1292 
1293  // Create the type of the conversion function.
1294  FunctionProtoType::ExtProtoInfo ConvExtInfo(
1296  /*IsVariadic=*/false, /*IsCXXMethod=*/true));
1297  // The conversion function is always const and noexcept.
1298  ConvExtInfo.TypeQuals = Qualifiers();
1299  ConvExtInfo.TypeQuals.addConst();
1300  ConvExtInfo.ExceptionSpec.Type = EST_BasicNoexcept;
1301  QualType ConvTy =
1302  S.Context.getFunctionType(PtrToFunctionTy, None, ConvExtInfo);
1303 
1304  SourceLocation Loc = IntroducerRange.getBegin();
1305  DeclarationName ConversionName
1307  S.Context.getCanonicalType(PtrToFunctionTy));
1308  DeclarationNameLoc ConvNameLoc;
1309  // Construct a TypeSourceInfo for the conversion function, and wire
1310  // all the parameters appropriately for the FunctionProtoTypeLoc
1311  // so that everything works during transformation/instantiation of
1312  // generic lambdas.
1313  // The main reason for wiring up the parameters of the conversion
1314  // function with that of the call operator is so that constructs
1315  // like the following work:
1316  // auto L = [](auto b) { <-- 1
1317  // return [](auto a) -> decltype(a) { <-- 2
1318  // return a;
1319  // };
1320  // };
1321  // int (*fp)(int) = L(5);
1322  // Because the trailing return type can contain DeclRefExprs that refer
1323  // to the original call operator's variables, we hijack the call
1324  // operators ParmVarDecls below.
1325  TypeSourceInfo *ConvNamePtrToFunctionTSI =
1326  S.Context.getTrivialTypeSourceInfo(PtrToFunctionTy, Loc);
1327  ConvNameLoc.NamedType.TInfo = ConvNamePtrToFunctionTSI;
1328 
1329  // The conversion function is a conversion to a pointer-to-function.
1330  TypeSourceInfo *ConvTSI = S.Context.getTrivialTypeSourceInfo(ConvTy, Loc);
1331  FunctionProtoTypeLoc ConvTL =
1332  ConvTSI->getTypeLoc().getAs<FunctionProtoTypeLoc>();
1333  // Get the result of the conversion function which is a pointer-to-function.
1334  PointerTypeLoc PtrToFunctionTL =
1335  ConvTL.getReturnLoc().getAs<PointerTypeLoc>();
1336  // Do the same for the TypeSourceInfo that is used to name the conversion
1337  // operator.
1338  PointerTypeLoc ConvNamePtrToFunctionTL =
1339  ConvNamePtrToFunctionTSI->getTypeLoc().getAs<PointerTypeLoc>();
1340 
1341  // Get the underlying function types that the conversion function will
1342  // be converting to (should match the type of the call operator).
1343  FunctionProtoTypeLoc CallOpConvTL =
1344  PtrToFunctionTL.getPointeeLoc().getAs<FunctionProtoTypeLoc>();
1345  FunctionProtoTypeLoc CallOpConvNameTL =
1346  ConvNamePtrToFunctionTL.getPointeeLoc().getAs<FunctionProtoTypeLoc>();
1347 
1348  // Wire up the FunctionProtoTypeLocs with the call operator's parameters.
1349  // These parameter's are essentially used to transform the name and
1350  // the type of the conversion operator. By using the same parameters
1351  // as the call operator's we don't have to fix any back references that
1352  // the trailing return type of the call operator's uses (such as
1353  // decltype(some_type<decltype(a)>::type{} + decltype(a){}) etc.)
1354  // - we can simply use the return type of the call operator, and
1355  // everything should work.
1356  SmallVector<ParmVarDecl *, 4> InvokerParams;
1357  for (unsigned I = 0, N = CallOperator->getNumParams(); I != N; ++I) {
1358  ParmVarDecl *From = CallOperator->getParamDecl(I);
1359 
1360  InvokerParams.push_back(ParmVarDecl::Create(
1361  S.Context,
1362  // Temporarily add to the TU. This is set to the invoker below.
1364  From->getLocation(), From->getIdentifier(), From->getType(),
1365  From->getTypeSourceInfo(), From->getStorageClass(),
1366  /*DefArg=*/nullptr));
1367  CallOpConvTL.setParam(I, From);
1368  CallOpConvNameTL.setParam(I, From);
1369  }
1370 
1372  S.Context, Class, Loc,
1373  DeclarationNameInfo(ConversionName, Loc, ConvNameLoc), ConvTy, ConvTSI,
1374  /*isInline=*/true, ExplicitSpecifier(),
1375  S.getLangOpts().CPlusPlus17 ? CSK_constexpr : CSK_unspecified,
1376  CallOperator->getBody()->getEndLoc());
1377  Conversion->setAccess(AS_public);
1378  Conversion->setImplicit(true);
1379 
1380  if (Class->isGenericLambda()) {
1381  // Create a template version of the conversion operator, using the template
1382  // parameter list of the function call operator.
1383  FunctionTemplateDecl *TemplateCallOperator =
1384  CallOperator->getDescribedFunctionTemplate();
1385  FunctionTemplateDecl *ConversionTemplate =
1387  Loc, ConversionName,
1388  TemplateCallOperator->getTemplateParameters(),
1389  Conversion);
1390  ConversionTemplate->setAccess(AS_public);
1391  ConversionTemplate->setImplicit(true);
1392  Conversion->setDescribedFunctionTemplate(ConversionTemplate);
1393  Class->addDecl(ConversionTemplate);
1394  } else
1395  Class->addDecl(Conversion);
1396  // Add a non-static member function that will be the result of
1397  // the conversion with a certain unique ID.
1398  DeclarationName InvokerName = &S.Context.Idents.get(
1400  // FIXME: Instead of passing in the CallOperator->getTypeSourceInfo()
1401  // we should get a prebuilt TrivialTypeSourceInfo from Context
1402  // using FunctionTy & Loc and get its TypeLoc as a FunctionProtoTypeLoc
1403  // then rewire the parameters accordingly, by hoisting up the InvokeParams
1404  // loop below and then use its Params to set Invoke->setParams(...) below.
1405  // This would avoid the 'const' qualifier of the calloperator from
1406  // contaminating the type of the invoker, which is currently adjusted
1407  // in SemaTemplateDeduction.cpp:DeduceTemplateArguments. Fixing the
1408  // trailing return type of the invoker would require a visitor to rebuild
1409  // the trailing return type and adjusting all back DeclRefExpr's to refer
1410  // to the new static invoker parameters - not the call operator's.
1412  S.Context, Class, Loc, DeclarationNameInfo(InvokerName, Loc),
1413  InvokerFunctionTy, CallOperator->getTypeSourceInfo(), SC_Static,
1414  /*isInline=*/true, CSK_unspecified, CallOperator->getBody()->getEndLoc());
1415  for (unsigned I = 0, N = CallOperator->getNumParams(); I != N; ++I)
1416  InvokerParams[I]->setOwningFunction(Invoke);
1417  Invoke->setParams(InvokerParams);
1418  Invoke->setAccess(AS_private);
1419  Invoke->setImplicit(true);
1420  if (Class->isGenericLambda()) {
1421  FunctionTemplateDecl *TemplateCallOperator =
1422  CallOperator->getDescribedFunctionTemplate();
1423  FunctionTemplateDecl *StaticInvokerTemplate = FunctionTemplateDecl::Create(
1424  S.Context, Class, Loc, InvokerName,
1425  TemplateCallOperator->getTemplateParameters(),
1426  Invoke);
1427  StaticInvokerTemplate->setAccess(AS_private);
1428  StaticInvokerTemplate->setImplicit(true);
1429  Invoke->setDescribedFunctionTemplate(StaticInvokerTemplate);
1430  Class->addDecl(StaticInvokerTemplate);
1431  } else
1432  Class->addDecl(Invoke);
1433 }
1434 
1435 /// Add a lambda's conversion to block pointer.
1437  SourceRange IntroducerRange,
1438  CXXRecordDecl *Class,
1439  CXXMethodDecl *CallOperator) {
1441  CallOperator->getType()->castAs<FunctionProtoType>());
1442  QualType BlockPtrTy = S.Context.getBlockPointerType(FunctionTy);
1443 
1444  FunctionProtoType::ExtProtoInfo ConversionEPI(
1446  /*IsVariadic=*/false, /*IsCXXMethod=*/true));
1447  ConversionEPI.TypeQuals = Qualifiers();
1448  ConversionEPI.TypeQuals.addConst();
1449  QualType ConvTy = S.Context.getFunctionType(BlockPtrTy, None, ConversionEPI);
1450 
1451  SourceLocation Loc = IntroducerRange.getBegin();
1452  DeclarationName Name
1454  S.Context.getCanonicalType(BlockPtrTy));
1455  DeclarationNameLoc NameLoc;
1456  NameLoc.NamedType.TInfo = S.Context.getTrivialTypeSourceInfo(BlockPtrTy, Loc);
1458  S.Context, Class, Loc, DeclarationNameInfo(Name, Loc, NameLoc), ConvTy,
1459  S.Context.getTrivialTypeSourceInfo(ConvTy, Loc),
1460  /*isInline=*/true, ExplicitSpecifier(), CSK_unspecified,
1461  CallOperator->getBody()->getEndLoc());
1462  Conversion->setAccess(AS_public);
1463  Conversion->setImplicit(true);
1464  Class->addDecl(Conversion);
1465 }
1466 
1468  SourceLocation ImplicitCaptureLoc,
1469  bool IsOpenMPMapping) {
1470  // VLA captures don't have a stored initialization expression.
1471  if (Cap.isVLATypeCapture())
1472  return ExprResult();
1473 
1474  // An init-capture is initialized directly from its stored initializer.
1475  if (Cap.isInitCapture())
1476  return Cap.getVariable()->getInit();
1477 
1478  // For anything else, build an initialization expression. For an implicit
1479  // capture, the capture notionally happens at the capture-default, so use
1480  // that location here.
1481  SourceLocation Loc =
1482  ImplicitCaptureLoc.isValid() ? ImplicitCaptureLoc : Cap.getLocation();
1483 
1484  // C++11 [expr.prim.lambda]p21:
1485  // When the lambda-expression is evaluated, the entities that
1486  // are captured by copy are used to direct-initialize each
1487  // corresponding non-static data member of the resulting closure
1488  // object. (For array members, the array elements are
1489  // direct-initialized in increasing subscript order.) These
1490  // initializations are performed in the (unspecified) order in
1491  // which the non-static data members are declared.
1492 
1493  // C++ [expr.prim.lambda]p12:
1494  // An entity captured by a lambda-expression is odr-used (3.2) in
1495  // the scope containing the lambda-expression.
1496  ExprResult Init;
1497  IdentifierInfo *Name = nullptr;
1498  if (Cap.isThisCapture()) {
1499  QualType ThisTy = getCurrentThisType();
1500  Expr *This = BuildCXXThisExpr(Loc, ThisTy, ImplicitCaptureLoc.isValid());
1501  if (Cap.isCopyCapture())
1502  Init = CreateBuiltinUnaryOp(Loc, UO_Deref, This);
1503  else
1504  Init = This;
1505  } else {
1506  assert(Cap.isVariableCapture() && "unknown kind of capture");
1507  VarDecl *Var = Cap.getVariable();
1508  Name = Var->getIdentifier();
1509  Init = BuildDeclarationNameExpr(
1510  CXXScopeSpec(), DeclarationNameInfo(Var->getDeclName(), Loc), Var);
1511  }
1512 
1513  // In OpenMP, the capture kind doesn't actually describe how to capture:
1514  // variables are "mapped" onto the device in a process that does not formally
1515  // make a copy, even for a "copy capture".
1516  if (IsOpenMPMapping)
1517  return Init;
1518 
1519  if (Init.isInvalid())
1520  return ExprError();
1521 
1522  Expr *InitExpr = Init.get();
1524  Name, Cap.getCaptureType(), Loc);
1525  InitializationKind InitKind =
1526  InitializationKind::CreateDirect(Loc, Loc, Loc);
1527  InitializationSequence InitSeq(*this, Entity, InitKind, InitExpr);
1528  return InitSeq.Perform(*this, Entity, InitKind, InitExpr);
1529 }
1530 
1532  Scope *CurScope) {
1533  LambdaScopeInfo LSI = *cast<LambdaScopeInfo>(FunctionScopes.back());
1534  ActOnFinishFunctionBody(LSI.CallOperator, Body);
1535  return BuildLambdaExpr(StartLoc, Body->getEndLoc(), &LSI);
1536 }
1537 
1538 static LambdaCaptureDefault
1540  switch (ICS) {
1542  return LCD_None;
1544  return LCD_ByCopy;
1547  return LCD_ByRef;
1549  llvm_unreachable("block capture in lambda");
1550  }
1551  llvm_unreachable("Unknown implicit capture style");
1552 }
1553 
1555  if (From.isInitCapture()) {
1556  Expr *Init = From.getVariable()->getInit();
1557  if (Init && Init->HasSideEffects(Context))
1558  return true;
1559  }
1560 
1561  if (!From.isCopyCapture())
1562  return false;
1563 
1564  const QualType T = From.isThisCapture()
1565  ? getCurrentThisType()->getPointeeType()
1566  : From.getCaptureType();
1567 
1568  if (T.isVolatileQualified())
1569  return true;
1570 
1571  const Type *BaseT = T->getBaseElementTypeUnsafe();
1572  if (const CXXRecordDecl *RD = BaseT->getAsCXXRecordDecl())
1573  return !RD->isCompleteDefinition() || !RD->hasTrivialCopyConstructor() ||
1574  !RD->hasTrivialDestructor();
1575 
1576  return false;
1577 }
1578 
1580  const Capture &From) {
1581  if (CaptureHasSideEffects(From))
1582  return false;
1583 
1584  if (From.isVLATypeCapture())
1585  return false;
1586 
1587  auto diag = Diag(From.getLocation(), diag::warn_unused_lambda_capture);
1588  if (From.isThisCapture())
1589  diag << "'this'";
1590  else
1591  diag << From.getVariable();
1592  diag << From.isNonODRUsed();
1593  diag << FixItHint::CreateRemoval(CaptureRange);
1594  return true;
1595 }
1596 
1597 /// Create a field within the lambda class or captured statement record for the
1598 /// given capture.
1600  const sema::Capture &Capture) {
1601  SourceLocation Loc = Capture.getLocation();
1602  QualType FieldType = Capture.getCaptureType();
1603 
1604  TypeSourceInfo *TSI = nullptr;
1605  if (Capture.isVariableCapture()) {
1606  auto *Var = Capture.getVariable();
1607  if (Var->isInitCapture())
1608  TSI = Capture.getVariable()->getTypeSourceInfo();
1609  }
1610 
1611  // FIXME: Should we really be doing this? A null TypeSourceInfo seems more
1612  // appropriate, at least for an implicit capture.
1613  if (!TSI)
1614  TSI = Context.getTrivialTypeSourceInfo(FieldType, Loc);
1615 
1616  // Build the non-static data member.
1617  FieldDecl *Field =
1618  FieldDecl::Create(Context, RD, Loc, Loc, nullptr, FieldType, TSI, nullptr,
1619  false, ICIS_NoInit);
1620  // If the variable being captured has an invalid type, mark the class as
1621  // invalid as well.
1622  if (!FieldType->isDependentType()) {
1623  if (RequireCompleteType(Loc, FieldType, diag::err_field_incomplete)) {
1624  RD->setInvalidDecl();
1625  Field->setInvalidDecl();
1626  } else {
1627  NamedDecl *Def;
1628  FieldType->isIncompleteType(&Def);
1629  if (Def && Def->isInvalidDecl()) {
1630  RD->setInvalidDecl();
1631  Field->setInvalidDecl();
1632  }
1633  }
1634  }
1635  Field->setImplicit(true);
1636  Field->setAccess(AS_private);
1637  RD->addDecl(Field);
1638 
1639  if (Capture.isVLATypeCapture())
1640  Field->setCapturedVLAType(Capture.getCapturedVLAType());
1641 
1642  return Field;
1643 }
1644 
1646  LambdaScopeInfo *LSI) {
1647  // Collect information from the lambda scope.
1649  SmallVector<Expr *, 4> CaptureInits;
1650  SourceLocation CaptureDefaultLoc = LSI->CaptureDefaultLoc;
1651  LambdaCaptureDefault CaptureDefault =
1653  CXXRecordDecl *Class;
1654  CXXMethodDecl *CallOperator;
1655  SourceRange IntroducerRange;
1656  bool ExplicitParams;
1657  bool ExplicitResultType;
1658  CleanupInfo LambdaCleanup;
1659  bool ContainsUnexpandedParameterPack;
1660  bool IsGenericLambda;
1661  {
1662  CallOperator = LSI->CallOperator;
1663  Class = LSI->Lambda;
1664  IntroducerRange = LSI->IntroducerRange;
1665  ExplicitParams = LSI->ExplicitParams;
1666  ExplicitResultType = !LSI->HasImplicitReturnType;
1667  LambdaCleanup = LSI->Cleanup;
1668  ContainsUnexpandedParameterPack = LSI->ContainsUnexpandedParameterPack;
1669  IsGenericLambda = Class->isGenericLambda();
1670 
1671  CallOperator->setLexicalDeclContext(Class);
1672  Decl *TemplateOrNonTemplateCallOperatorDecl =
1673  CallOperator->getDescribedFunctionTemplate()
1674  ? CallOperator->getDescribedFunctionTemplate()
1675  : cast<Decl>(CallOperator);
1676 
1677  // FIXME: Is this really the best choice? Keeping the lexical decl context
1678  // set as CurContext seems more faithful to the source.
1679  TemplateOrNonTemplateCallOperatorDecl->setLexicalDeclContext(Class);
1680 
1681  PopExpressionEvaluationContext();
1682 
1683  // True if the current capture has a used capture or default before it.
1684  bool CurHasPreviousCapture = CaptureDefault != LCD_None;
1685  SourceLocation PrevCaptureLoc = CurHasPreviousCapture ?
1686  CaptureDefaultLoc : IntroducerRange.getBegin();
1687 
1688  for (unsigned I = 0, N = LSI->Captures.size(); I != N; ++I) {
1689  const Capture &From = LSI->Captures[I];
1690 
1691  if (From.isInvalid())
1692  return ExprError();
1693 
1694  assert(!From.isBlockCapture() && "Cannot capture __block variables");
1695  bool IsImplicit = I >= LSI->NumExplicitCaptures;
1696  SourceLocation ImplicitCaptureLoc =
1697  IsImplicit ? CaptureDefaultLoc : SourceLocation();
1698 
1699  // Use source ranges of explicit captures for fixits where available.
1700  SourceRange CaptureRange = LSI->ExplicitCaptureRanges[I];
1701 
1702  // Warn about unused explicit captures.
1703  bool IsCaptureUsed = true;
1704  if (!CurContext->isDependentContext() && !IsImplicit &&
1705  !From.isODRUsed()) {
1706  // Initialized captures that are non-ODR used may not be eliminated.
1707  // FIXME: Where did the IsGenericLambda here come from?
1708  bool NonODRUsedInitCapture =
1709  IsGenericLambda && From.isNonODRUsed() && From.isInitCapture();
1710  if (!NonODRUsedInitCapture) {
1711  bool IsLast = (I + 1) == LSI->NumExplicitCaptures;
1712  SourceRange FixItRange;
1713  if (CaptureRange.isValid()) {
1714  if (!CurHasPreviousCapture && !IsLast) {
1715  // If there are no captures preceding this capture, remove the
1716  // following comma.
1717  FixItRange = SourceRange(CaptureRange.getBegin(),
1718  getLocForEndOfToken(CaptureRange.getEnd()));
1719  } else {
1720  // Otherwise, remove the comma since the last used capture.
1721  FixItRange = SourceRange(getLocForEndOfToken(PrevCaptureLoc),
1722  CaptureRange.getEnd());
1723  }
1724  }
1725 
1726  IsCaptureUsed = !DiagnoseUnusedLambdaCapture(FixItRange, From);
1727  }
1728  }
1729 
1730  if (CaptureRange.isValid()) {
1731  CurHasPreviousCapture |= IsCaptureUsed;
1732  PrevCaptureLoc = CaptureRange.getEnd();
1733  }
1734 
1735  // Map the capture to our AST representation.
1736  LambdaCapture Capture = [&] {
1737  if (From.isThisCapture()) {
1738  // Capturing 'this' implicitly with a default of '[=]' is deprecated,
1739  // because it results in a reference capture. Don't warn prior to
1740  // C++2a; there's nothing that can be done about it before then.
1741  if (getLangOpts().CPlusPlus2a && IsImplicit &&
1742  CaptureDefault == LCD_ByCopy) {
1743  Diag(From.getLocation(), diag::warn_deprecated_this_capture);
1744  Diag(CaptureDefaultLoc, diag::note_deprecated_this_capture)
1746  getLocForEndOfToken(CaptureDefaultLoc), ", this");
1747  }
1748  return LambdaCapture(From.getLocation(), IsImplicit,
1749  From.isCopyCapture() ? LCK_StarThis : LCK_This);
1750  } else if (From.isVLATypeCapture()) {
1751  return LambdaCapture(From.getLocation(), IsImplicit, LCK_VLAType);
1752  } else {
1753  assert(From.isVariableCapture() && "unknown kind of capture");
1754  VarDecl *Var = From.getVariable();
1756  From.isCopyCapture() ? LCK_ByCopy : LCK_ByRef;
1757  return LambdaCapture(From.getLocation(), IsImplicit, Kind, Var,
1758  From.getEllipsisLoc());
1759  }
1760  }();
1761 
1762  // Form the initializer for the capture field.
1763  ExprResult Init = BuildCaptureInit(From, ImplicitCaptureLoc);
1764 
1765  // FIXME: Skip this capture if the capture is not used, the initializer
1766  // has no side-effects, the type of the capture is trivial, and the
1767  // lambda is not externally visible.
1768 
1769  // Add a FieldDecl for the capture and form its initializer.
1770  BuildCaptureField(Class, From);
1771  Captures.push_back(Capture);
1772  CaptureInits.push_back(Init.get());
1773  }
1774 
1775  // C++11 [expr.prim.lambda]p6:
1776  // The closure type for a lambda-expression with no lambda-capture
1777  // has a public non-virtual non-explicit const conversion function
1778  // to pointer to function having the same parameter and return
1779  // types as the closure type's function call operator.
1780  if (Captures.empty() && CaptureDefault == LCD_None)
1781  addFunctionPointerConversion(*this, IntroducerRange, Class,
1782  CallOperator);
1783 
1784  // Objective-C++:
1785  // The closure type for a lambda-expression has a public non-virtual
1786  // non-explicit const conversion function to a block pointer having the
1787  // same parameter and return types as the closure type's function call
1788  // operator.
1789  // FIXME: Fix generic lambda to block conversions.
1790  if (getLangOpts().Blocks && getLangOpts().ObjC && !IsGenericLambda)
1791  addBlockPointerConversion(*this, IntroducerRange, Class, CallOperator);
1792 
1793  // Finalize the lambda class.
1794  SmallVector<Decl*, 4> Fields(Class->fields());
1795  ActOnFields(nullptr, Class->getLocation(), Class, Fields, SourceLocation(),
1797  CheckCompletedCXXClass(Class);
1798  }
1799 
1800  Cleanup.mergeFrom(LambdaCleanup);
1801 
1802  LambdaExpr *Lambda = LambdaExpr::Create(Context, Class, IntroducerRange,
1803  CaptureDefault, CaptureDefaultLoc,
1804  Captures,
1805  ExplicitParams, ExplicitResultType,
1806  CaptureInits, EndLoc,
1807  ContainsUnexpandedParameterPack);
1808  // If the lambda expression's call operator is not explicitly marked constexpr
1809  // and we are not in a dependent context, analyze the call operator to infer
1810  // its constexpr-ness, suppressing diagnostics while doing so.
1811  if (getLangOpts().CPlusPlus17 && !CallOperator->isInvalidDecl() &&
1812  !CallOperator->isConstexpr() &&
1813  !isa<CoroutineBodyStmt>(CallOperator->getBody()) &&
1814  !Class->getDeclContext()->isDependentContext()) {
1815  CallOperator->setConstexprKind(
1816  CheckConstexprFunctionDefinition(CallOperator,
1817  CheckConstexprKind::CheckValid)
1818  ? CSK_constexpr
1819  : CSK_unspecified);
1820  }
1821 
1822  // Emit delayed shadowing warnings now that the full capture list is known.
1823  DiagnoseShadowingLambdaDecls(LSI);
1824 
1825  if (!CurContext->isDependentContext()) {
1826  switch (ExprEvalContexts.back().Context) {
1827  // C++11 [expr.prim.lambda]p2:
1828  // A lambda-expression shall not appear in an unevaluated operand
1829  // (Clause 5).
1830  case ExpressionEvaluationContext::Unevaluated:
1831  case ExpressionEvaluationContext::UnevaluatedList:
1832  case ExpressionEvaluationContext::UnevaluatedAbstract:
1833  // C++1y [expr.const]p2:
1834  // A conditional-expression e is a core constant expression unless the
1835  // evaluation of e, following the rules of the abstract machine, would
1836  // evaluate [...] a lambda-expression.
1837  //
1838  // This is technically incorrect, there are some constant evaluated contexts
1839  // where this should be allowed. We should probably fix this when DR1607 is
1840  // ratified, it lays out the exact set of conditions where we shouldn't
1841  // allow a lambda-expression.
1842  case ExpressionEvaluationContext::ConstantEvaluated:
1843  // We don't actually diagnose this case immediately, because we
1844  // could be within a context where we might find out later that
1845  // the expression is potentially evaluated (e.g., for typeid).
1846  ExprEvalContexts.back().Lambdas.push_back(Lambda);
1847  break;
1848 
1849  case ExpressionEvaluationContext::DiscardedStatement:
1850  case ExpressionEvaluationContext::PotentiallyEvaluated:
1851  case ExpressionEvaluationContext::PotentiallyEvaluatedIfUsed:
1852  break;
1853  }
1854  }
1855 
1856  return MaybeBindToTemporary(Lambda);
1857 }
1858 
1860  SourceLocation ConvLocation,
1861  CXXConversionDecl *Conv,
1862  Expr *Src) {
1863  // Make sure that the lambda call operator is marked used.
1864  CXXRecordDecl *Lambda = Conv->getParent();
1865  CXXMethodDecl *CallOperator
1866  = cast<CXXMethodDecl>(
1867  Lambda->lookup(
1868  Context.DeclarationNames.getCXXOperatorName(OO_Call)).front());
1869  CallOperator->setReferenced();
1870  CallOperator->markUsed(Context);
1871 
1872  ExprResult Init = PerformCopyInitialization(
1874  /*NRVO=*/false),
1875  CurrentLocation, Src);
1876  if (!Init.isInvalid())
1877  Init = ActOnFinishFullExpr(Init.get(), /*DiscardedValue*/ false);
1878 
1879  if (Init.isInvalid())
1880  return ExprError();
1881 
1882  // Create the new block to be returned.
1883  BlockDecl *Block = BlockDecl::Create(Context, CurContext, ConvLocation);
1884 
1885  // Set the type information.
1886  Block->setSignatureAsWritten(CallOperator->getTypeSourceInfo());
1887  Block->setIsVariadic(CallOperator->isVariadic());
1888  Block->setBlockMissingReturnType(false);
1889 
1890  // Add parameters.
1891  SmallVector<ParmVarDecl *, 4> BlockParams;
1892  for (unsigned I = 0, N = CallOperator->getNumParams(); I != N; ++I) {
1893  ParmVarDecl *From = CallOperator->getParamDecl(I);
1894  BlockParams.push_back(ParmVarDecl::Create(
1895  Context, Block, From->getBeginLoc(), From->getLocation(),
1896  From->getIdentifier(), From->getType(), From->getTypeSourceInfo(),
1897  From->getStorageClass(),
1898  /*DefArg=*/nullptr));
1899  }
1900  Block->setParams(BlockParams);
1901 
1902  Block->setIsConversionFromLambda(true);
1903 
1904  // Add capture. The capture uses a fake variable, which doesn't correspond
1905  // to any actual memory location. However, the initializer copy-initializes
1906  // the lambda object.
1907  TypeSourceInfo *CapVarTSI =
1908  Context.getTrivialTypeSourceInfo(Src->getType());
1909  VarDecl *CapVar = VarDecl::Create(Context, Block, ConvLocation,
1910  ConvLocation, nullptr,
1911  Src->getType(), CapVarTSI,
1912  SC_None);
1913  BlockDecl::Capture Capture(/*variable=*/CapVar, /*byRef=*/false,
1914  /*nested=*/false, /*copy=*/Init.get());
1915  Block->setCaptures(Context, Capture, /*CapturesCXXThis=*/false);
1916 
1917  // Add a fake function body to the block. IR generation is responsible
1918  // for filling in the actual body, which cannot be expressed as an AST.
1919  Block->setBody(new (Context) CompoundStmt(ConvLocation));
1920 
1921  // Create the block literal expression.
1922  Expr *BuildBlock = new (Context) BlockExpr(Block, Conv->getConversionType());
1923  ExprCleanupObjects.push_back(Block);
1924  Cleanup.setExprNeedsCleanups(true);
1925 
1926  return BuildBlock;
1927 }
void setImplicit(bool I=true)
Definition: DeclBase.h:559
Represents a function declaration or definition.
Definition: Decl.h:1784
SourceRange IntroducerRange
Source range covering the lambda introducer [...].
Definition: ScopeInfo.h:801
DeclaratorChunk::FunctionTypeInfo & getFunctionTypeInfo()
getFunctionTypeInfo - Retrieves the function type info object (looking through parentheses).
Definition: DeclSpec.h:2278
static DiagnosticBuilder Diag(DiagnosticsEngine *Diags, const LangOptions &Features, FullSourceLoc TokLoc, const char *TokBegin, const char *TokRangeBegin, const char *TokRangeEnd, unsigned DiagID)
Produce a diagnostic highlighting some portion of a literal.
SourceLocation getBeginLoc() const
Definition: Stmt.h:2679
A class which contains all the information about a particular captured value.
Definition: Decl.h:3957
if(T->getSizeExpr()) TRY_TO(TraverseStmt(T -> getSizeExpr()))
unsigned getRawEncoding() const
When a SourceLocation itself cannot be used, this returns an (opaque) 32-bit integer encoding for it...
A (possibly-)qualified type.
Definition: Type.h:643
bool ExplicitParams
Whether the (empty) parameter list is explicit.
Definition: ScopeInfo.h:815
virtual unsigned getManglingNumber(const CXXMethodDecl *CallOperator)=0
Retrieve the mangling number of a new lambda expression with the given call operator within this cont...
TemplateParameterList * GLTemplateParameterList
If this is a generic lambda, and the template parameter list has been created (from the TemplateParam...
Definition: ScopeInfo.h:848
bool SetTypeQual(TQ T, SourceLocation Loc)
Definition: DeclSpec.cpp:914
Stmt - This represents one statement.
Definition: Stmt.h:66
An instance of this object exists for each enum constant that is defined.
Definition: Decl.h:2855
QualType ReturnType
ReturnType - The target type of return statements in this context, or null if unknown.
Definition: ScopeInfo.h:658
StorageClass getStorageClass() const
Returns the storage class as written in the source.
Definition: Decl.h:1034
bool isConstexpr() const
Whether this is a (C++11) constexpr function or constexpr constructor.
Definition: Decl.h:2144
DeclarationName getCXXConversionFunctionName(CanQualType Ty)
Returns the name of a C++ conversion function for the given Type.
QualType getCaptureType() const
Retrieve the capture type for this capture, which is effectively the type of the non-static data memb...
Definition: ScopeInfo.h:624
Decl - This represents one declaration (or definition), e.g.
Definition: DeclBase.h:88
bool isVariadic() const
Whether this function prototype is variadic.
Definition: Type.h:4041
LambdaCaptureDefault
The default, if any, capture method for a lambda expression.
Definition: Lambda.h:22
CanQualType getCanonicalFunctionResultType(QualType ResultType) const
Adjust the given function result type.
StringRef P
ExprResult BuildBlockForLambdaConversion(SourceLocation CurrentLocation, SourceLocation ConvLocation, CXXConversionDecl *Conv, Expr *Src)
bool isCopyCapture() const
Definition: ScopeInfo.h:583
static InitializationKind CreateDirect(SourceLocation InitLoc, SourceLocation LParenLoc, SourceLocation RParenLoc)
Create a direct initialization.
QualType getBlockPointerType(QualType T) const
Return the uniqued reference to the type for a block of the specified type.
The base class of the type hierarchy.
Definition: Type.h:1436
void setParams(ArrayRef< ParmVarDecl *> NewParamInfo)
Definition: Decl.cpp:4464
bool isFunctionDeclarator(unsigned &idx) const
isFunctionDeclarator - This method returns true if the declarator is a function declarator (looking t...
Definition: DeclSpec.h:2247
A container of type source information.
Definition: Decl.h:86
Store information needed for an explicit specifier.
Definition: DeclCXX.h:1792
QualType getConversionType() const
Returns the type that this conversion function is converting to.
Definition: DeclCXX.h:2727
void setInitStyle(InitializationStyle Style)
Definition: Decl.h:1300
Describes the capture of a variable or of this, or of a C++1y init-capture.
Definition: LambdaCapture.h:25
This file provides some common utility functions for processing Lambda related AST Constructs...
bool isODRUsed() const
Definition: ScopeInfo.h:595
Represents a variable declaration or definition.
Definition: Decl.h:827
bool DiagnoseUnusedLambdaCapture(SourceRange CaptureRange, const sema::Capture &From)
Diagnose if an explicit lambda capture is unused.
Information about one declarator, including the parsed type information and the identifier.
Definition: DeclSpec.h:1775
QualType getReturnType() const
Definition: Decl.h:2365
VarDecl * createLambdaInitCaptureVarDecl(SourceLocation Loc, QualType InitCaptureType, SourceLocation EllipsisLoc, IdentifierInfo *Id, unsigned InitStyle, Expr *Init)
Create a dummy variable within the declcontext of the lambda&#39;s call operator, for name lookup purpose...
Definition: SemaLambda.cpp:849
const T * getAs() const
Member-template getAs<specific type>&#39;.
Definition: Type.h:6858
bool This(InterpState &S, CodePtr OpPC)
Definition: Interp.h:830
Extra information about a function prototype.
Definition: Type.h:3805
bool isAmbiguous() const
Definition: Lookup.h:301
bool isInvalidDecl() const
Definition: DeclBase.h:553
Stores a list of template parameters for a TemplateDecl and its derived classes.
Definition: DeclTemplate.h:67
static InitializationKind CreateDirectList(SourceLocation InitLoc)
bool tryCaptureVariable(VarDecl *Var, SourceLocation Loc, TryCaptureKind Kind, SourceLocation EllipsisLoc, bool BuildAndDiagnose, QualType &CaptureType, QualType &DeclRefType, const unsigned *const FunctionScopeIndexToStopAt)
Try to capture the given variable.
Definition: SemaExpr.cpp:16021
bool CaptureHasSideEffects(const sema::Capture &From)
Does copying/destroying the captured variable have side effects?
Represents an expression – generally a full-expression – that introduces cleanups to be run at the ...
Definition: ExprCXX.h:3306
Represents a parameter to a function.
Definition: Decl.h:1600
CXXRecordDecl * createLambdaClosureType(SourceRange IntroducerRange, TypeSourceInfo *Info, bool KnownDependent, LambdaCaptureDefault CaptureDefault)
Create a new lambda closure type.
Definition: SemaLambda.cpp:241
Defines the clang::Expr interface and subclasses for C++ expressions.
The collection of all-type qualifiers we support.
Definition: Type.h:137
tok::TokenKind ContextKind
static CXXMethodDecl * Create(ASTContext &C, CXXRecordDecl *RD, SourceLocation StartLoc, const DeclarationNameInfo &NameInfo, QualType T, TypeSourceInfo *TInfo, StorageClass SC, bool isInline, ConstexprSpecKind ConstexprKind, SourceLocation EndLocation)
Definition: DeclCXX.cpp:2039
bool FTIHasNonVoidParameters(const DeclaratorChunk::FunctionTypeInfo &FTI)
Definition: SemaInternal.h:36
IdentifierInfo * getIdentifier() const
Get the identifier that names this declaration, if there is one.
Definition: Decl.h:269
Represents a struct/union/class.
Definition: Decl.h:3662
Scope * getTemplateParamParent()
Definition: Scope.h:262
FunctionType::ExtInfo ExtInfo
Definition: Type.h:3806
One of these records is kept for each identifier that is lexed.
bool isConst() const
Definition: DeclCXX.h:1945
sema::LambdaScopeInfo * getCurGenericLambda()
Retrieve the current generic lambda info, if any.
Definition: Sema.cpp:1868
Holds long-lived AST nodes (such as types and decls) that can be referred to throughout the semantic ...
Definition: ASTContext.h:160
ArrayRef< QualType > getParamTypes() const
Definition: Type.h:3934
field_range fields() const
Definition: Decl.h:3877
TypeSourceInfo * getTypeSourceInfo(ASTContext &Context, QualType T)
Creates a TypeSourceInfo for the given type.
SourceLocation getBeginLoc() const LLVM_READONLY
Definition: Stmt.cpp:274
LambdaCaptureKind
The different capture forms in a lambda introducer.
Definition: Lambda.h:33
Represents a member of a struct/union/class.
Definition: Decl.h:2643
bool isReferenceType() const
Definition: Type.h:6403
bool Equals(const DeclContext *DC) const
Determine whether this declaration context is equivalent to the declaration context DC...
Definition: DeclBase.h:1903
void setParams(ArrayRef< ParmVarDecl *> NewParamInfo)
Definition: Decl.h:2356
SourceLocation getBeginLoc() const LLVM_READONLY
Definition: Decl.h:746
static CXXRecordDecl * CreateLambda(const ASTContext &C, DeclContext *DC, TypeSourceInfo *Info, SourceLocation Loc, bool DependentLambda, bool IsGeneric, LambdaCaptureDefault CaptureDefault)
Definition: DeclCXX.cpp:141
bool ContainsUnexpandedParameterPack
Whether the lambda contains an unexpanded parameter pack.
Definition: ScopeInfo.h:821
IdentifierTable & Idents
Definition: ASTContext.h:579
An r-value expression (a pr-value in the C++11 taxonomy) produces a temporary value.
Definition: Specifiers.h:125
ArrayRef< ParmVarDecl * > parameters() const
Definition: Decl.h:2325
DeclClass * getAsSingle() const
Definition: Lookup.h:507
bool isThisCapture() const
Definition: ScopeInfo.h:578
void setNameLoc(SourceLocation Loc)
Definition: TypeLoc.h:523
Represents the results of name lookup.
Definition: Lookup.h:46
PtrTy get() const
Definition: Ownership.h:170
Stmt * getBody(const FunctionDecl *&Definition) const
Retrieve the body (definition) of the function.
Definition: Decl.cpp:2849
< Capturing the *this object by copy
Definition: Lambda.h:36
static LambdaCaptureDefault mapImplicitCaptureStyle(CapturingScopeInfo::ImplicitCaptureStyle ICS)
static InitializedEntity InitializeLambdaToBlock(SourceLocation BlockVarLoc, QualType Type, bool NRVO)
Keeps track of the mangled names of lambda expressions and block literals within a particular context...
FunctionTemplateDecl * getDescribedFunctionTemplate() const
Retrieves the function template that is described by this function declaration.
Definition: Decl.cpp:3486
bool CheckCXXThisCapture(SourceLocation Loc, bool Explicit=false, bool BuildAndDiagnose=true, const unsigned *const FunctionScopeIndexToStopAt=nullptr, bool ByCopy=false)
Make sure the value of &#39;this&#39; is actually available in the current context, if it is a potentially ev...
unsigned getNumTypeObjects() const
Return the number of types applied to this declarator.
Definition: DeclSpec.h:2185
const VariableArrayType * getCapturedVLAType() const
Definition: ScopeInfo.h:609
bool containsUnexpandedParameterPack() const
Whether this type is or contains an unexpanded parameter pack, used to support C++0x variadic templat...
Definition: Type.h:1871
A builtin binary operation expression such as "x + y" or "x <= y".
Definition: Expr.h:3409
bool isVolatileQualified() const
Determine whether this type is volatile-qualified.
Definition: Type.h:6218
void finishedExplicitCaptures()
Note when all explicit captures have been added.
Definition: ScopeInfo.h:891
llvm::Error Error
DeclContext * getLambdaAwareParentOfDeclContext(DeclContext *DC)
Definition: ASTLambda.h:70
Scope - A scope is a transient data structure that is used while parsing the program.
Definition: Scope.h:40
ExprResult Perform(Sema &S, const InitializedEntity &Entity, const InitializationKind &Kind, MultiExprArg Args, QualType *ResultType=nullptr)
Perform the actual initialization of the given entity based on the computed initialization sequence...
Definition: SemaInit.cpp:7744
void addInitCapture(sema::LambdaScopeInfo *LSI, VarDecl *Var)
Add an init-capture to a lambda scope.
Definition: SemaLambda.cpp:877
static EnumDecl * findCommonEnumForBlockReturns(ArrayRef< ReturnStmt *> returns)
Attempt to find a common type T for which all of the returned expressions in a block are enumerator-l...
Definition: SemaLambda.cpp:645
bool hasNameForLinkage() const
Is this tag type named, either directly or via being defined in a typedef of this type...
Definition: Decl.h:3339
Represents a C++ nested-name-specifier or a global scope specifier.
Definition: DeclSpec.h:63
A C++ lambda expression, which produces a function object (of unspecified type) that can be invoked l...
Definition: ExprCXX.h:1818
unsigned NumExplicitTemplateParams
The number of parameters in the template parameter list that were explicitly specified by the user...
Definition: ScopeInfo.h:833
static VarDecl * Create(ASTContext &C, DeclContext *DC, SourceLocation StartLoc, SourceLocation IdLoc, IdentifierInfo *Id, QualType T, TypeSourceInfo *TInfo, StorageClass S)
Definition: Decl.cpp:1965
const LangOptions & getLangOpts() const
Definition: Sema.h:1288
bool isLambdaCallOperator(const CXXMethodDecl *MD)
Definition: ASTLambda.h:27
ExprResult BuildCaptureInit(const sema::Capture &Capture, SourceLocation ImplicitCaptureLoc, bool IsOpenMPMapping=false)
Initialize the given capture with a suitable expression.
static FunctionTemplateDecl * Create(ASTContext &C, DeclContext *DC, SourceLocation L, DeclarationName Name, TemplateParameterList *Params, NamedDecl *Decl)
Create a function template node.
StringRef getLambdaStaticInvokerName()
Definition: ASTLambda.h:22
QualType getLambdaConversionFunctionResultType(const FunctionProtoType *CallOpType)
Get the return type to use for a lambda&#39;s conversion function(s) to function pointer type...
static void addFunctionPointerConversion(Sema &S, SourceRange IntroducerRange, CXXRecordDecl *Class, CXXMethodDecl *CallOperator)
Add a lambda&#39;s conversion to function pointer, as described in C++11 [expr.prim.lambda]p6.
void addLambdaParameters(ArrayRef< LambdaIntroducer::LambdaCapture > Captures, CXXMethodDecl *CallOperator, Scope *CurScope)
Introduce the lambda parameters into scope.
Definition: SemaLambda.cpp:537
CallingConv getDefaultCallingConvention(bool IsVariadic, bool IsCXXMethod, bool IsBuiltin=false) const
Retrieves the default calling convention for the current target.
TypeSpecTypeLoc pushTypeSpec(QualType T)
Pushes space for a typespec TypeLoc.
CleanupInfo Cleanup
Whether any of the capture expressions requires cleanups.
Definition: ScopeInfo.h:818
TyLocType push(QualType T)
Pushes space for a new TypeLoc of the given type.
lookup_result lookup(DeclarationName Name) const
lookup - Find the declarations (if any) with the given Name in this context.
Definition: DeclBase.cpp:1609
ExtInfo withCallingConv(CallingConv cc) const
Definition: Type.h:3609
ImplicitCaptureStyle ImpCaptureStyle
Definition: ScopeInfo.h:637
bool isIntegralOrUnscopedEnumerationType() const
Determine whether this type is an integral or unscoped enumeration type.
Definition: Type.cpp:1859
ConditionalOperator - The ?: ternary operator.
Definition: Expr.h:3707
Sema - This implements semantic analysis and AST building for C.
Definition: Sema.h:331
CompoundStmt - This represents a group of statements like { stmt stmt }.
Definition: Stmt.h:1320
bool Mutable
Whether this is a mutable lambda.
Definition: ScopeInfo.h:812
CXXRecordDecl * getAsCXXRecordDecl() const
Retrieves the CXXRecordDecl that this type refers to, either because the type is a RecordType or beca...
Definition: Type.cpp:1692
SmallVector< ReturnStmt *, 4 > Returns
The list of return statements that occur within the function or block, if there is any chance of appl...
Definition: ScopeInfo.h:190
Represents a prototype with parameter type info, e.g.
Definition: Type.h:3725
static ImplicitCastExpr * Create(const ASTContext &Context, QualType T, CastKind Kind, Expr *Operand, const CXXCastPath *BasePath, ExprValueKind Cat)
Definition: Expr.cpp:1981
DeclarationNameTable DeclarationNames
Definition: ASTContext.h:582
void finishLambdaExplicitCaptures(sema::LambdaScopeInfo *LSI)
Note that we have finished the explicit captures for the given lambda.
Definition: SemaLambda.cpp:516
SourceLocation getEllipsisLoc() const
Retrieve the source location of the ellipsis, whose presence indicates that the capture is a pack exp...
Definition: ScopeInfo.h:619
SmallVector< LambdaCapture, 4 > Captures
Definition: DeclSpec.h:2584
SourceLocation PotentialThisCaptureLocation
Definition: ScopeInfo.h:883
unsigned NumExplicitCaptures
The number of captures in the Captures list that are explicit captures.
Definition: ScopeInfo.h:809
TypeSourceInfo * getTrivialTypeSourceInfo(QualType T, SourceLocation Loc=SourceLocation()) const
Allocate a TypeSourceInfo where all locations have been initialized to a given location, which defaults to the empty location.
bool isVariableCapture() const
Definition: ScopeInfo.h:579
bool HasSideEffects(const ASTContext &Ctx, bool IncludePossibleEffects=true) const
HasSideEffects - This routine returns true for all those expressions which have any effect other than...
Definition: Expr.cpp:3343
TemplateParameterList * getTemplateParameters() const
Get the list of template parameters.
Definition: DeclTemplate.h:406
static CXXConversionDecl * Create(ASTContext &C, CXXRecordDecl *RD, SourceLocation StartLoc, const DeclarationNameInfo &NameInfo, QualType T, TypeSourceInfo *TInfo, bool isInline, ExplicitSpecifier ES, ConstexprSpecKind ConstexprKind, SourceLocation EndLocation)
Definition: DeclCXX.cpp:2637
DeclContext * getLexicalParent()
getLexicalParent - Returns the containing lexical DeclContext.
Definition: DeclBase.h:1795
CXXMethodDecl * CallOperator
The lambda&#39;s compiler-generated operator().
Definition: ScopeInfo.h:798
Represents a block literal declaration, which is like an unnamed FunctionDecl.
Definition: Decl.h:3951
bool isInvalid() const
Definition: ScopeInfo.h:590
ExprResult ActOnLambdaExpr(SourceLocation StartLoc, Stmt *Body, Scope *CurScope)
ActOnLambdaExpr - This is called when the body of a lambda expression was successfully completed...
This represents one expression.
Definition: Expr.h:108
bool isVariadic() const
Whether this function is variadic.
Definition: Decl.cpp:2807
int Id
Definition: ASTDiff.cpp:190
bool hasLocalStorage() const
Returns true if a variable with function scope is a non-static local variable.
Definition: Decl.h:1050
This file defines the classes used to store parsed information about declaration-specifiers and decla...
const T * castAs() const
Member-template castAs<specific type>.
Definition: Type.h:6923
BlockExpr - Adaptor class for mixing a BlockDecl with expressions.
Definition: Expr.h:5551
T getAs() const
Convert to the specified TypeLoc type, returning a null TypeLoc if this TypeLoc is not of the desired...
Definition: TypeLoc.h:86
void setInit(Expr *I)
Definition: Decl.cpp:2268
void setInvalidDecl(bool Invalid=true)
setInvalidDecl - Indicates the Decl had a semantic error.
Definition: DeclBase.cpp:132
void setRetValue(Expr *E)
Definition: Stmt.h:2655
bool isFileContext() const
Definition: DeclBase.h:1849
DeclContext * getDeclContext()
Definition: DeclBase.h:438
static TemplateParameterList * getGenericLambdaTemplateParameterList(LambdaScopeInfo *LSI, Sema &SemaRef)
Definition: SemaLambda.cpp:228
llvm::DenseMap< unsigned, SourceRange > ExplicitCaptureRanges
A map of explicit capture indices to their introducer source ranges.
Definition: ScopeInfo.h:872
void buildLambdaScope(sema::LambdaScopeInfo *LSI, CXXMethodDecl *CallOperator, SourceRange IntroducerRange, LambdaCaptureDefault CaptureDefault, SourceLocation CaptureDefaultLoc, bool ExplicitParams, bool ExplicitResultType, bool Mutable)
Endow the lambda scope info with the relevant properties.
Definition: SemaLambda.cpp:481
bool isCaptured(VarDecl *Var) const
Determine whether the given variable has been captured.
Definition: ScopeInfo.h:687
QualType getType() const
Definition: Expr.h:137
bool isFunctionOrMethod() const
Definition: DeclBase.h:1831
Capture & getCapture(VarDecl *Var)
Retrieve the capture of the given variable, if it has been captured already.
Definition: ScopeInfo.h:696
Direct list-initialization (C++11)
Definition: Decl.h:838
static LambdaExpr * Create(const ASTContext &C, CXXRecordDecl *Class, SourceRange IntroducerRange, LambdaCaptureDefault CaptureDefault, SourceLocation CaptureDefaultLoc, ArrayRef< LambdaCapture > Captures, bool ExplicitParams, bool ExplicitResultType, ArrayRef< Expr *> CaptureInits, SourceLocation ClosingBrace, bool ContainsUnexpandedParameterPack)
Construct a new lambda expression.
Definition: ExprCXX.cpp:1214
DeclarationName getCXXOperatorName(OverloadedOperatorKind Op)
Get the name of the overloadable C++ operator corresponding to Op.
static bool isInInlineFunction(const DeclContext *DC)
Determine whether the given context is or is enclosed in an inline function.
Definition: SemaLambda.cpp:263
DeclContext * getParent()
getParent - Returns the containing DeclContext.
Definition: DeclBase.h:1779
ReturnStmt - This represents a return, optionally of an expression: return; return 4;...
Definition: Stmt.h:2620
bool isInvalid() const
Definition: Ownership.h:166
SourceLocation getEnd() const
QualType getFunctionType(QualType ResultTy, ArrayRef< QualType > Args, const FunctionProtoType::ExtProtoInfo &EPI) const
Return a normal function type with a typed argument list.
Definition: ASTContext.h:1387
struct CXXOpName CXXOperatorName
bool isDependentContext() const
Determines whether this context is dependent on a template parameter.
Definition: DeclBase.cpp:1089
Common base class for placeholders for types that get replaced by placeholder type deduction: C++11 a...
Definition: Type.h:4783
const Type * getBaseElementTypeUnsafe() const
Get the base element type of this type, potentially discarding type qualifiers.
Definition: Type.h:6798
Represents a C++ conversion function within a class.
Definition: DeclCXX.h:2690
QualType getTypeDeclType(const TypeDecl *Decl, const TypeDecl *PrevDecl=nullptr) const
Return the unique reference to the type for the specified type declaration.
Definition: ASTContext.h:1403
SourceLocation getLocation() const
Retrieve the location at which this variable was captured.
Definition: ScopeInfo.h:615
bool isNull() const
Return true if this QualType doesn&#39;t point to a type yet.
Definition: Type.h:708
CallingConv
CallingConv - Specifies the calling convention that a function uses.
Definition: Specifiers.h:265
TypeLoc getReturnLoc() const
Definition: TypeLoc.h:1446
static TemplateParameterList * Create(const ASTContext &C, SourceLocation TemplateLoc, SourceLocation LAngleLoc, ArrayRef< NamedDecl *> Params, SourceLocation RAngleLoc, Expr *RequiresClause)
SourceLocation getEndLoc() const LLVM_READONLY
Definition: Stmt.cpp:287
static InitializationKind CreateCopy(SourceLocation InitLoc, SourceLocation EqualLoc, bool AllowExplicitConvs=false)
Create a copy initialization.
ConstexprSpecKind getConstexprSpecifier() const
Definition: DeclSpec.h:731
void setIsVariadic(bool value)
Definition: Decl.h:4027
ExprResult BuildLambdaExpr(SourceLocation StartLoc, SourceLocation EndLoc, sema::LambdaScopeInfo *LSI)
Complete a lambda-expression having processed and attached the lambda body.
QualType getPackExpansionType(QualType Pattern, Optional< unsigned > NumExpansions)
SmallVector< NamedDecl *, 4 > TemplateParams
Store the list of the template parameters for a generic lambda.
Definition: ScopeInfo.h:843
void setIsConversionFromLambda(bool val=true)
Definition: Decl.h:4098
SourceLocation DefaultLoc
Definition: DeclSpec.h:2582
Kind
bool hasWeakerNullability(NullabilityKind L, NullabilityKind R)
Return true if L has a weaker nullability annotation than R.
Definition: Specifiers.h:329
ActionResult - This structure is used while parsing/acting on expressions, stmts, etc...
Definition: Ownership.h:153
VarDecl * getVariable() const
Definition: ScopeInfo.h:604
ExtProtoInfo getExtProtoInfo() const
Definition: Type.h:3938
unsigned getNumExprs() const
Return the number of expressions in this paren list.
Definition: Expr.h:5141
Encodes a location in the source.
IdentifierInfo & get(StringRef Name)
Return the identifier token info for the specified named identifier.
QualType getReturnType() const
Definition: Type.h:3651
Expr * getRetValue()
Definition: Stmt.h:2653
A helper class that allows the use of isa/cast/dyncast to detect TagType objects of enums...
Definition: Type.h:4470
static InitializedEntity InitializeLambdaCapture(IdentifierInfo *VarID, QualType FieldType, SourceLocation Loc)
Create the initialization entity for a lambda capture.
CXXRecordDecl * Lambda
The class that describes the lambda.
Definition: ScopeInfo.h:795
static Optional< unsigned > getStackIndexOfNearestEnclosingCaptureReadyLambda(ArrayRef< const clang::sema::FunctionScopeInfo *> FunctionScopes, VarDecl *VarToCapture)
Examines the FunctionScopeInfo stack to determine the nearest enclosing lambda (to the current lambda...
Definition: SemaLambda.cpp:63
SourceRange ExplicitTemplateParamsRange
Source range covering the explicit template parameter list (if it exists).
Definition: ScopeInfo.h:836
MutableArrayRef< Expr * > MultiExprArg
Definition: Ownership.h:273
void setReferenced(bool R=true)
Definition: DeclBase.h:588
void setLambdaMangling(unsigned ManglingNumber, Decl *ContextDecl, bool HasKnownInternalLinkage=false)
Set the mangling number and context declaration for a lambda class.
Definition: DeclCXX.h:1731
Represents a static or instance method of a struct/union/class.
Definition: DeclCXX.h:1905
void handleLambdaNumbering(CXXRecordDecl *Class, CXXMethodDecl *Method, Optional< std::tuple< unsigned, bool, Decl *>> Mangling=None)
Number lambda for linkage purposes if necessary.
Definition: SemaLambda.cpp:432
No ref-qualifier was provided.
Definition: Type.h:1389
C-style initialization with assignment.
Definition: Decl.h:832
const ParmVarDecl * getParamDecl(unsigned i) const
Definition: Decl.h:2348
bool isVLATypeCapture() const
Definition: ScopeInfo.h:586
CanQualType VoidTy
Definition: ASTContext.h:1015
bool isGenericLambda() const
Determine whether this class describes a generic lambda function object (i.e.
Definition: DeclCXX.cpp:1389
Describes the kind of initialization being performed, along with location information for tokens rela...
SmallVector< Capture, 4 > Captures
Captures - The captures.
Definition: ScopeInfo.h:650
ImplicitCastExpr - Allows us to explicitly represent implicit type conversions, which have no direct ...
Definition: Expr.h:3249
SourceLocation CaptureDefaultLoc
Source location of the &#39;&&#39; or &#39;=&#39; specifying the default capture type, if any.
Definition: ScopeInfo.h:805
Expr ** getExprs()
Definition: Expr.h:5152
StmtExpr - This is the GNU Statement Expression extension: ({int X=4; X;}).
Definition: Expr.h:3926
static EnumDecl * findEnumForBlockReturn(Expr *E)
If this expression is an enumerator-like expression of some type T, return the type T; otherwise...
Definition: SemaLambda.cpp:573
Represents a pack expansion of types.
Definition: Type.h:5431
DeclarationNameLoc - Additional source/type location info for a declaration name. ...
SourceRange getSourceRange() const LLVM_READONLY
Get the source range that spans this declarator.
Definition: DeclSpec.h:1899
This file provides some common utility functions for processing Lambdas.
static ParmVarDecl * Create(ASTContext &C, DeclContext *DC, SourceLocation StartLoc, SourceLocation IdLoc, IdentifierInfo *Id, QualType T, TypeSourceInfo *TInfo, StorageClass S, Expr *DefArg)
Definition: Decl.cpp:2657
Dataflow Directional Tag Classes.
void ActOnLambdaError(SourceLocation StartLoc, Scope *CurScope, bool IsInstantiation=false)
ActOnLambdaError - If there is an error parsing a lambda, this callback is invoked to pop the informa...
void setBody(CompoundStmt *B)
Definition: Decl.h:4031
ConstexprSpecKind
Define the kind of constexpr specifier.
Definition: Specifiers.h:32
bool isValid() const
Return true if this is a valid SourceLocation object.
LambdaCaptureDefault Default
Definition: DeclSpec.h:2583
DeclContext - This is used only as base class of specific decl types that can act as declaration cont...
Definition: DeclBase.h:1271
void deduceClosureReturnType(sema::CapturingScopeInfo &CSI)
Deduce a block or lambda&#39;s return type based on the return statements present in the body...
Definition: SemaLambda.cpp:692
bool isRecord() const
Definition: DeclBase.h:1858
Optional< unsigned > getStackIndexOfNearestEnclosingCaptureCapableLambda(ArrayRef< const sema::FunctionScopeInfo *> FunctionScopes, VarDecl *VarToCapture, Sema &S)
Examines the FunctionScopeInfo stack to determine the nearest enclosing lambda (to the current lambda...
Definition: SemaLambda.cpp:173
static FixItHint CreateRemoval(CharSourceRange RemoveRange)
Create a code modification hint that removes the given source range.
Definition: Diagnostic.h:118
const Expr * getInit() const
Definition: Decl.h:1234
static void addBlockPointerConversion(Sema &S, SourceRange IntroducerRange, CXXRecordDecl *Class, CXXMethodDecl *CallOperator)
Add a lambda&#39;s conversion to block pointer.
The name of a declaration.
const CXXRecordDecl * getParent() const
Return the parent of this method declaration, which is the class in which this method is defined...
Definition: DeclCXX.h:2028
MangleNumberingContext & getManglingNumberContext(const DeclContext *DC)
Retrieve the context for computing mangling numbers in the given DeclContext.
Represents an enum.
Definition: Decl.h:3395
bool isParameterPack() const
Determine whether this variable is actually a function parameter pack or init-capture pack...
Definition: Decl.cpp:2449
bool isInitCapture() const
Whether this variable is the implicit variable for a lambda init-capture.
Definition: Decl.h:1426
DeclarationNameInfo - A collector data type for bundling together a DeclarationName and the correspnd...
void ActOnLambdaExplicitTemplateParameterList(SourceLocation LAngleLoc, ArrayRef< NamedDecl *> TParams, SourceLocation RAngleLoc)
This is called after parsing the explicit template parameter list on a lambda (if it exists) in C++2a...
Definition: SemaLambda.cpp:520
bool isUndeducedType() const
Determine whether this type is an undeduced type, meaning that it somehow involves a C++11 &#39;auto&#39; typ...
Definition: Type.h:6773
void setInitCapture(bool IC)
Definition: Decl.h:1429
Capturing variable-length array type.
Definition: Lambda.h:38
void ActOnStartOfLambdaDefinition(LambdaIntroducer &Intro, Declarator &ParamInfo, Scope *CurScope)
ActOnStartOfLambdaDefinition - This is called just before we start parsing the body of a lambda; it a...
Definition: SemaLambda.cpp:884
void setConstexprKind(ConstexprSpecKind CSK)
Definition: Decl.h:2147
CanQualType DependentTy
Definition: ASTContext.h:1044
std::tuple< MangleNumberingContext *, Decl * > getCurrentMangleNumberContext(const DeclContext *DC)
Compute the mangling number context for a lambda expression or block literal.
Definition: SemaLambda.cpp:276
TypeSourceInfo * getTypeSourceInfo() const
Definition: Decl.h:723
bool hasSameType(QualType T1, QualType T2) const
Determine whether the given types T1 and T2 are equivalent.
Definition: ASTContext.h:2305
Simple template class for restricting typo correction candidates to ones having a single Decl* of the...
QualType getAutoDeductType() const
C++11 deduction pattern for &#39;auto&#39; type.
static FixItHint CreateInsertion(SourceLocation InsertionLoc, StringRef Code, bool BeforePreviousInsertions=false)
Create a code modification hint that inserts the given code string at a specific location.
Definition: Diagnostic.h:92
void addDecl(Decl *D)
Add the declaration D into this context.
Definition: DeclBase.cpp:1521
Optional< NullabilityKind > getNullability(const ASTContext &context) const
Determine the nullability of the given type.
Definition: Type.cpp:3825
Capturing the *this object by reference.
Definition: Lambda.h:34
void markUsed(ASTContext &C)
Mark the declaration used, in the sense of odr-use.
Definition: DeclBase.cpp:413
Capture & getCXXThisCapture()
Retrieve the capture of C++ &#39;this&#39;, if it has been captured.
Definition: ScopeInfo.h:681
bool isIncompleteType(NamedDecl **Def=nullptr) const
Types are partitioned into 3 broad categories (C99 6.2.5p1): object types, function types...
Definition: Type.cpp:2118
FieldDecl * BuildCaptureField(RecordDecl *RD, const sema::Capture &Capture)
Build a FieldDecl suitable to hold the given capture.
CanQualType getCanonicalType(QualType T) const
Return the canonical (structural) type corresponding to the specified potentially non-canonical type ...
Definition: ASTContext.h:2289
void setSignatureAsWritten(TypeSourceInfo *Sig)
Definition: Decl.h:4033
TypeLoc getTypeLoc() const
Return the TypeLoc wrapper for the type source info.
Definition: TypeLoc.h:240
bool isInitCapture() const
Determine whether this capture is an init-capture.
Definition: ScopeInfo.cpp:219
static BlockDecl * Create(ASTContext &C, DeclContext *DC, SourceLocation L)
Definition: Decl.cpp:4640
Call-style initialization (C++98)
Definition: Decl.h:835
TranslationUnitDecl * getTranslationUnitDecl() const
Definition: ASTContext.h:1008
void addCapture(VarDecl *Var, bool isBlock, bool isByref, bool isNested, SourceLocation Loc, SourceLocation EllipsisLoc, QualType CaptureType, bool Invalid)
Definition: ScopeInfo.h:660
Describes the sequence of initializations required to initialize a given object or reference with a s...
ActionResult< Expr * > ExprResult
Definition: Ownership.h:263
Represents a C++ struct/union/class.
Definition: DeclCXX.h:255
bool isValid() const
bool isVoidType() const
Definition: Type.h:6650
Capturing by reference.
Definition: Lambda.h:37
TryCaptureKind
Definition: Sema.h:4354
const DeclSpec & getDeclSpec() const
getDeclSpec - Return the declaration-specifier that this declarator was declared with.
Definition: DeclSpec.h:1864
bool isCXXThisCaptured() const
Determine whether the C++ &#39;this&#39; is captured.
Definition: ScopeInfo.h:678
bool containsUnexpandedParameterPack() const
Whether this expression contains an unexpanded parameter pack (for C++11 variadic templates)...
Definition: Expr.h:223
QualType getPointerType(QualType T) const
Return the uniqued reference to the type for a pointer to the specified type.
void setCapturedVLAType(const VariableArrayType *VLAType)
Set the captured variable length array type for this field.
Definition: Decl.cpp:4021
void addAttr(Attr *A)
Definition: DeclBase.cpp:830
Defines the clang::TargetInfo interface.
Represents a complete lambda introducer.
Definition: DeclSpec.h:2559
ExprResult ExprError()
Definition: Ownership.h:279
void setDescribedFunctionTemplate(FunctionTemplateDecl *Template)
Definition: Decl.cpp:3490
bool isDependentType() const
Whether this type is a dependent type, meaning that its definition somehow depends on a template para...
Definition: Type.h:2121
A reference to a declared variable, function, enum, etc.
Definition: Expr.h:1146
bool isNonODRUsed() const
Definition: ScopeInfo.h:596
CXXMethodDecl * startLambdaDefinition(CXXRecordDecl *Class, SourceRange IntroducerRange, TypeSourceInfo *MethodType, SourceLocation EndLoc, ArrayRef< ParmVarDecl *> Params, ConstexprSpecKind ConstexprKind)
Start the definition of a lambda expression.
Definition: SemaLambda.cpp:359
QualType getType() const
Definition: Decl.h:655
bool empty() const
Return true if no decls were found.
Definition: Lookup.h:339
void setCaptures(ASTContext &Context, ArrayRef< Capture > Captures, bool CapturesCXXThis)
Definition: Decl.cpp:4475
A trivial tuple used to represent a source range.
void setLexicalDeclContext(DeclContext *DC)
Definition: DeclBase.cpp:299
ASTContext & Context
Definition: Sema.h:377
This represents a decl that may have a name.
Definition: Decl.h:248
bool isTranslationUnit() const
Definition: DeclBase.h:1854
void setAccess(AccessSpecifier AS)
Definition: DeclBase.h:468
void setBlockMissingReturnType(bool val=true)
Definition: Decl.h:4090
Describes an entity that is being initialized.
QualType buildLambdaInitCaptureInitialization(SourceLocation Loc, bool ByRef, SourceLocation EllipsisLoc, Optional< unsigned > NumExpansions, IdentifierInfo *Id, bool DirectInit, Expr *&Init)
Definition: SemaLambda.cpp:785
static FieldDecl * Create(const ASTContext &C, DeclContext *DC, SourceLocation StartLoc, SourceLocation IdLoc, IdentifierInfo *Id, QualType T, TypeSourceInfo *TInfo, Expr *BW, bool Mutable, InClassInitStyle InitStyle)
Definition: Decl.cpp:3924
unsigned getNumParams() const
Return the number of parameters this function must have based on its FunctionType.
Definition: Decl.cpp:3178
Wrapper for source info for pointers.
Definition: TypeLoc.h:1237
SourceLocation getBegin() const
bool isBlockCapture() const
Definition: ScopeInfo.h:585
static void adjustBlockReturnsToEnum(Sema &S, ArrayRef< ReturnStmt *> returns, QualType returnType)
Adjust the given return statements so that they formally return the given type.
Definition: SemaLambda.cpp:666
No in-class initializer.
Definition: Specifiers.h:259
Declaration of a template function.
Definition: DeclTemplate.h:961
Attr - This represents one attribute.
Definition: Attr.h:45
SourceLocation getLocation() const
Definition: DeclBase.h:429
QualType getType() const
Return the type wrapped by this type source info.
Definition: Decl.h:97
Expr * IgnoreParens() LLVM_READONLY
Skip past any parentheses which might surround this expression until reaching a fixed point...
Definition: Expr.cpp:2962