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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, nullptr);
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  CXXRecordDecl *Class, SourceRange IntroducerRange,
361  TypeSourceInfo *MethodTypeInfo, SourceLocation EndLoc,
362  ArrayRef<ParmVarDecl *> Params, ConstexprSpecKind ConstexprKind,
363  Optional<std::pair<unsigned, Decl *>> Mangling) {
364  QualType MethodType = MethodTypeInfo->getType();
365  TemplateParameterList *TemplateParams =
366  getGenericLambdaTemplateParameterList(getCurLambda(), *this);
367  // If a lambda appears in a dependent context or is a generic lambda (has
368  // template parameters) and has an 'auto' return type, deduce it to a
369  // dependent type.
370  if (Class->isDependentContext() || TemplateParams) {
371  const FunctionProtoType *FPT = MethodType->castAs<FunctionProtoType>();
372  QualType Result = FPT->getReturnType();
373  if (Result->isUndeducedType()) {
374  Result = SubstAutoType(Result, Context.DependentTy);
375  MethodType = Context.getFunctionType(Result, FPT->getParamTypes(),
376  FPT->getExtProtoInfo());
377  }
378  }
379 
380  // C++11 [expr.prim.lambda]p5:
381  // The closure type for a lambda-expression has a public inline function
382  // call operator (13.5.4) whose parameters and return type are described by
383  // the lambda-expression's parameter-declaration-clause and
384  // trailing-return-type respectively.
385  DeclarationName MethodName
386  = Context.DeclarationNames.getCXXOperatorName(OO_Call);
387  DeclarationNameLoc MethodNameLoc;
388  MethodNameLoc.CXXOperatorName.BeginOpNameLoc
389  = IntroducerRange.getBegin().getRawEncoding();
390  MethodNameLoc.CXXOperatorName.EndOpNameLoc
391  = IntroducerRange.getEnd().getRawEncoding();
393  Context, Class, EndLoc,
394  DeclarationNameInfo(MethodName, IntroducerRange.getBegin(),
395  MethodNameLoc),
396  MethodType, MethodTypeInfo, SC_None,
397  /*isInline=*/true, ConstexprKind, EndLoc);
398  Method->setAccess(AS_public);
399  if (!TemplateParams)
400  Class->addDecl(Method);
401 
402  // Temporarily set the lexical declaration context to the current
403  // context, so that the Scope stack matches the lexical nesting.
404  Method->setLexicalDeclContext(CurContext);
405  // Create a function template if we have a template parameter list
406  FunctionTemplateDecl *const TemplateMethod = TemplateParams ?
407  FunctionTemplateDecl::Create(Context, Class,
408  Method->getLocation(), MethodName,
409  TemplateParams,
410  Method) : nullptr;
411  if (TemplateMethod) {
412  TemplateMethod->setAccess(AS_public);
413  Method->setDescribedFunctionTemplate(TemplateMethod);
414  Class->addDecl(TemplateMethod);
415  TemplateMethod->setLexicalDeclContext(CurContext);
416  }
417 
418  // Add parameters.
419  if (!Params.empty()) {
420  Method->setParams(Params);
421  CheckParmsForFunctionDef(Params,
422  /*CheckParameterNames=*/false);
423 
424  for (auto P : Method->parameters())
425  P->setOwningFunction(Method);
426  }
427 
428  if (Mangling) {
429  Class->setLambdaMangling(Mangling->first, Mangling->second);
430  } else {
432  Decl *ManglingContextDecl;
433  std::tie(MCtx, ManglingContextDecl) =
434  getCurrentMangleNumberContext(Class->getDeclContext());
435  if (MCtx) {
436  unsigned ManglingNumber = MCtx->getManglingNumber(Method);
437  Class->setLambdaMangling(ManglingNumber, ManglingContextDecl);
438  }
439  }
440 
441  return Method;
442 }
443 
445  CXXMethodDecl *CallOperator,
446  SourceRange IntroducerRange,
447  LambdaCaptureDefault CaptureDefault,
448  SourceLocation CaptureDefaultLoc,
449  bool ExplicitParams,
450  bool ExplicitResultType,
451  bool Mutable) {
452  LSI->CallOperator = CallOperator;
453  CXXRecordDecl *LambdaClass = CallOperator->getParent();
454  LSI->Lambda = LambdaClass;
455  if (CaptureDefault == LCD_ByCopy)
457  else if (CaptureDefault == LCD_ByRef)
459  LSI->CaptureDefaultLoc = CaptureDefaultLoc;
460  LSI->IntroducerRange = IntroducerRange;
461  LSI->ExplicitParams = ExplicitParams;
462  LSI->Mutable = Mutable;
463 
464  if (ExplicitResultType) {
465  LSI->ReturnType = CallOperator->getReturnType();
466 
467  if (!LSI->ReturnType->isDependentType() &&
468  !LSI->ReturnType->isVoidType()) {
469  if (RequireCompleteType(CallOperator->getBeginLoc(), LSI->ReturnType,
470  diag::err_lambda_incomplete_result)) {
471  // Do nothing.
472  }
473  }
474  } else {
475  LSI->HasImplicitReturnType = true;
476  }
477 }
478 
481 }
482 
484  ArrayRef<NamedDecl *> TParams,
485  SourceLocation RAngleLoc) {
486  LambdaScopeInfo *LSI = getCurLambda();
487  assert(LSI && "Expected a lambda scope");
488  assert(LSI->NumExplicitTemplateParams == 0 &&
489  "Already acted on explicit template parameters");
490  assert(LSI->TemplateParams.empty() &&
491  "Explicit template parameters should come "
492  "before invented (auto) ones");
493  assert(!TParams.empty() &&
494  "No template parameters to act on");
495  LSI->TemplateParams.append(TParams.begin(), TParams.end());
496  LSI->NumExplicitTemplateParams = TParams.size();
497  LSI->ExplicitTemplateParamsRange = {LAngleLoc, RAngleLoc};
498 }
499 
502  CXXMethodDecl *CallOperator, Scope *CurScope) {
503  // Introduce our parameters into the function scope
504  for (unsigned p = 0, NumParams = CallOperator->getNumParams();
505  p < NumParams; ++p) {
506  ParmVarDecl *Param = CallOperator->getParamDecl(p);
507 
508  // If this has an identifier, add it to the scope stack.
509  if (CurScope && Param->getIdentifier()) {
510  bool Error = false;
511  // Resolution of CWG 2211 in C++17 renders shadowing ill-formed, but we
512  // retroactively apply it.
513  for (const auto &Capture : Captures) {
514  if (Capture.Id == Param->getIdentifier()) {
515  Error = true;
516  Diag(Param->getLocation(), diag::err_parameter_shadow_capture);
517  Diag(Capture.Loc, diag::note_var_explicitly_captured_here)
518  << Capture.Id << true;
519  }
520  }
521  if (!Error)
522  CheckShadow(CurScope, Param);
523 
524  PushOnScopeChains(Param, CurScope);
525  }
526  }
527 }
528 
529 /// If this expression is an enumerator-like expression of some type
530 /// T, return the type T; otherwise, return null.
531 ///
532 /// Pointer comparisons on the result here should always work because
533 /// it's derived from either the parent of an EnumConstantDecl
534 /// (i.e. the definition) or the declaration returned by
535 /// EnumType::getDecl() (i.e. the definition).
537  // An expression is an enumerator-like expression of type T if,
538  // ignoring parens and parens-like expressions:
539  E = E->IgnoreParens();
540 
541  // - it is an enumerator whose enum type is T or
542  if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) {
543  if (EnumConstantDecl *D
544  = dyn_cast<EnumConstantDecl>(DRE->getDecl())) {
545  return cast<EnumDecl>(D->getDeclContext());
546  }
547  return nullptr;
548  }
549 
550  // - it is a comma expression whose RHS is an enumerator-like
551  // expression of type T or
552  if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) {
553  if (BO->getOpcode() == BO_Comma)
554  return findEnumForBlockReturn(BO->getRHS());
555  return nullptr;
556  }
557 
558  // - it is a statement-expression whose value expression is an
559  // enumerator-like expression of type T or
560  if (StmtExpr *SE = dyn_cast<StmtExpr>(E)) {
561  if (Expr *last = dyn_cast_or_null<Expr>(SE->getSubStmt()->body_back()))
562  return findEnumForBlockReturn(last);
563  return nullptr;
564  }
565 
566  // - it is a ternary conditional operator (not the GNU ?:
567  // extension) whose second and third operands are
568  // enumerator-like expressions of type T or
569  if (ConditionalOperator *CO = dyn_cast<ConditionalOperator>(E)) {
570  if (EnumDecl *ED = findEnumForBlockReturn(CO->getTrueExpr()))
571  if (ED == findEnumForBlockReturn(CO->getFalseExpr()))
572  return ED;
573  return nullptr;
574  }
575 
576  // (implicitly:)
577  // - it is an implicit integral conversion applied to an
578  // enumerator-like expression of type T or
579  if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) {
580  // We can sometimes see integral conversions in valid
581  // enumerator-like expressions.
582  if (ICE->getCastKind() == CK_IntegralCast)
583  return findEnumForBlockReturn(ICE->getSubExpr());
584 
585  // Otherwise, just rely on the type.
586  }
587 
588  // - it is an expression of that formal enum type.
589  if (const EnumType *ET = E->getType()->getAs<EnumType>()) {
590  return ET->getDecl();
591  }
592 
593  // Otherwise, nope.
594  return nullptr;
595 }
596 
597 /// Attempt to find a type T for which the returned expression of the
598 /// given statement is an enumerator-like expression of that type.
600  if (Expr *retValue = ret->getRetValue())
601  return findEnumForBlockReturn(retValue);
602  return nullptr;
603 }
604 
605 /// Attempt to find a common type T for which all of the returned
606 /// expressions in a block are enumerator-like expressions of that
607 /// type.
609  ArrayRef<ReturnStmt*>::iterator i = returns.begin(), e = returns.end();
610 
611  // Try to find one for the first return.
613  if (!ED) return nullptr;
614 
615  // Check that the rest of the returns have the same enum.
616  for (++i; i != e; ++i) {
617  if (findEnumForBlockReturn(*i) != ED)
618  return nullptr;
619  }
620 
621  // Never infer an anonymous enum type.
622  if (!ED->hasNameForLinkage()) return nullptr;
623 
624  return ED;
625 }
626 
627 /// Adjust the given return statements so that they formally return
628 /// the given type. It should require, at most, an IntegralCast.
630  QualType returnType) {
632  i = returns.begin(), e = returns.end(); i != e; ++i) {
633  ReturnStmt *ret = *i;
634  Expr *retValue = ret->getRetValue();
635  if (S.Context.hasSameType(retValue->getType(), returnType))
636  continue;
637 
638  // Right now we only support integral fixup casts.
639  assert(returnType->isIntegralOrUnscopedEnumerationType());
640  assert(retValue->getType()->isIntegralOrUnscopedEnumerationType());
641 
642  ExprWithCleanups *cleanups = dyn_cast<ExprWithCleanups>(retValue);
643 
644  Expr *E = (cleanups ? cleanups->getSubExpr() : retValue);
645  E = ImplicitCastExpr::Create(S.Context, returnType, CK_IntegralCast,
646  E, /*base path*/ nullptr, VK_RValue);
647  if (cleanups) {
648  cleanups->setSubExpr(E);
649  } else {
650  ret->setRetValue(E);
651  }
652  }
653 }
654 
656  assert(CSI.HasImplicitReturnType);
657  // If it was ever a placeholder, it had to been deduced to DependentTy.
658  assert(CSI.ReturnType.isNull() || !CSI.ReturnType->isUndeducedType());
659  assert((!isa<LambdaScopeInfo>(CSI) || !getLangOpts().CPlusPlus14) &&
660  "lambda expressions use auto deduction in C++14 onwards");
661 
662  // C++ core issue 975:
663  // If a lambda-expression does not include a trailing-return-type,
664  // it is as if the trailing-return-type denotes the following type:
665  // - if there are no return statements in the compound-statement,
666  // or all return statements return either an expression of type
667  // void or no expression or braced-init-list, the type void;
668  // - otherwise, if all return statements return an expression
669  // and the types of the returned expressions after
670  // lvalue-to-rvalue conversion (4.1 [conv.lval]),
671  // array-to-pointer conversion (4.2 [conv.array]), and
672  // function-to-pointer conversion (4.3 [conv.func]) are the
673  // same, that common type;
674  // - otherwise, the program is ill-formed.
675  //
676  // C++ core issue 1048 additionally removes top-level cv-qualifiers
677  // from the types of returned expressions to match the C++14 auto
678  // deduction rules.
679  //
680  // In addition, in blocks in non-C++ modes, if all of the return
681  // statements are enumerator-like expressions of some type T, where
682  // T has a name for linkage, then we infer the return type of the
683  // block to be that type.
684 
685  // First case: no return statements, implicit void return type.
686  ASTContext &Ctx = getASTContext();
687  if (CSI.Returns.empty()) {
688  // It's possible there were simply no /valid/ return statements.
689  // In this case, the first one we found may have at least given us a type.
690  if (CSI.ReturnType.isNull())
691  CSI.ReturnType = Ctx.VoidTy;
692  return;
693  }
694 
695  // Second case: at least one return statement has dependent type.
696  // Delay type checking until instantiation.
697  assert(!CSI.ReturnType.isNull() && "We should have a tentative return type.");
698  if (CSI.ReturnType->isDependentType())
699  return;
700 
701  // Try to apply the enum-fuzz rule.
702  if (!getLangOpts().CPlusPlus) {
703  assert(isa<BlockScopeInfo>(CSI));
705  if (ED) {
706  CSI.ReturnType = Context.getTypeDeclType(ED);
708  return;
709  }
710  }
711 
712  // Third case: only one return statement. Don't bother doing extra work!
713  if (CSI.Returns.size() == 1)
714  return;
715 
716  // General case: many return statements.
717  // Check that they all have compatible return types.
718 
719  // We require the return types to strictly match here.
720  // Note that we've already done the required promotions as part of
721  // processing the return statement.
722  for (const ReturnStmt *RS : CSI.Returns) {
723  const Expr *RetE = RS->getRetValue();
724 
725  QualType ReturnType =
726  (RetE ? RetE->getType() : Context.VoidTy).getUnqualifiedType();
727  if (Context.getCanonicalFunctionResultType(ReturnType) ==
729  // Use the return type with the strictest possible nullability annotation.
730  auto RetTyNullability = ReturnType->getNullability(Ctx);
731  auto BlockNullability = CSI.ReturnType->getNullability(Ctx);
732  if (BlockNullability &&
733  (!RetTyNullability ||
734  hasWeakerNullability(*RetTyNullability, *BlockNullability)))
735  CSI.ReturnType = ReturnType;
736  continue;
737  }
738 
739  // FIXME: This is a poor diagnostic for ReturnStmts without expressions.
740  // TODO: It's possible that the *first* return is the divergent one.
741  Diag(RS->getBeginLoc(),
742  diag::err_typecheck_missing_return_type_incompatible)
743  << ReturnType << CSI.ReturnType << isa<LambdaScopeInfo>(CSI);
744  // Continue iterating so that we keep emitting diagnostics.
745  }
746 }
747 
749  SourceLocation Loc, bool ByRef, SourceLocation EllipsisLoc,
750  Optional<unsigned> NumExpansions, IdentifierInfo *Id, bool IsDirectInit,
751  Expr *&Init) {
752  // Create an 'auto' or 'auto&' TypeSourceInfo that we can use to
753  // deduce against.
754  QualType DeductType = Context.getAutoDeductType();
755  TypeLocBuilder TLB;
756  TLB.pushTypeSpec(DeductType).setNameLoc(Loc);
757  if (ByRef) {
758  DeductType = BuildReferenceType(DeductType, true, Loc, Id);
759  assert(!DeductType.isNull() && "can't build reference to auto");
760  TLB.push<ReferenceTypeLoc>(DeductType).setSigilLoc(Loc);
761  }
762  if (EllipsisLoc.isValid()) {
763  if (Init->containsUnexpandedParameterPack()) {
764  Diag(EllipsisLoc, getLangOpts().CPlusPlus2a
765  ? diag::warn_cxx17_compat_init_capture_pack
766  : diag::ext_init_capture_pack);
767  DeductType = Context.getPackExpansionType(DeductType, NumExpansions);
768  TLB.push<PackExpansionTypeLoc>(DeductType).setEllipsisLoc(EllipsisLoc);
769  } else {
770  // Just ignore the ellipsis for now and form a non-pack variable. We'll
771  // diagnose this later when we try to capture it.
772  }
773  }
774  TypeSourceInfo *TSI = TLB.getTypeSourceInfo(Context, DeductType);
775 
776  // Deduce the type of the init capture.
777  QualType DeducedType = deduceVarTypeFromInitializer(
778  /*VarDecl*/nullptr, DeclarationName(Id), DeductType, TSI,
779  SourceRange(Loc, Loc), IsDirectInit, Init);
780  if (DeducedType.isNull())
781  return QualType();
782 
783  // Are we a non-list direct initialization?
784  ParenListExpr *CXXDirectInit = dyn_cast<ParenListExpr>(Init);
785 
786  // Perform initialization analysis and ensure any implicit conversions
787  // (such as lvalue-to-rvalue) are enforced.
788  InitializedEntity Entity =
789  InitializedEntity::InitializeLambdaCapture(Id, DeducedType, Loc);
791  IsDirectInit
792  ? (CXXDirectInit ? InitializationKind::CreateDirect(
793  Loc, Init->getBeginLoc(), Init->getEndLoc())
796 
797  MultiExprArg Args = Init;
798  if (CXXDirectInit)
799  Args =
800  MultiExprArg(CXXDirectInit->getExprs(), CXXDirectInit->getNumExprs());
801  QualType DclT;
802  InitializationSequence InitSeq(*this, Entity, Kind, Args);
803  ExprResult Result = InitSeq.Perform(*this, Entity, Kind, Args, &DclT);
804 
805  if (Result.isInvalid())
806  return QualType();
807 
808  Init = Result.getAs<Expr>();
809  return DeducedType;
810 }
811 
813  QualType InitCaptureType,
814  SourceLocation EllipsisLoc,
816  unsigned InitStyle, Expr *Init) {
817  // FIXME: Retain the TypeSourceInfo from buildLambdaInitCaptureInitialization
818  // rather than reconstructing it here.
819  TypeSourceInfo *TSI = Context.getTrivialTypeSourceInfo(InitCaptureType, Loc);
820  if (auto PETL = TSI->getTypeLoc().getAs<PackExpansionTypeLoc>())
821  PETL.setEllipsisLoc(EllipsisLoc);
822 
823  // Create a dummy variable representing the init-capture. This is not actually
824  // used as a variable, and only exists as a way to name and refer to the
825  // init-capture.
826  // FIXME: Pass in separate source locations for '&' and identifier.
827  VarDecl *NewVD = VarDecl::Create(Context, CurContext, Loc,
828  Loc, Id, InitCaptureType, TSI, SC_Auto);
829  NewVD->setInitCapture(true);
830  NewVD->setReferenced(true);
831  // FIXME: Pass in a VarDecl::InitializationStyle.
832  NewVD->setInitStyle(static_cast<VarDecl::InitializationStyle>(InitStyle));
833  NewVD->markUsed(Context);
834  NewVD->setInit(Init);
835  if (NewVD->isParameterPack())
836  getCurLambda()->LocalPacks.push_back(NewVD);
837  return NewVD;
838 }
839 
841  assert(Var->isInitCapture() && "init capture flag should be set");
842  LSI->addCapture(Var, /*isBlock*/false, Var->getType()->isReferenceType(),
843  /*isNested*/false, Var->getLocation(), SourceLocation(),
844  Var->getType(), /*Invalid*/false);
845 }
846 
848  Declarator &ParamInfo,
849  Scope *CurScope) {
850  LambdaScopeInfo *const LSI = getCurLambda();
851  assert(LSI && "LambdaScopeInfo should be on stack!");
852 
853  // Determine if we're within a context where we know that the lambda will
854  // be dependent, because there are template parameters in scope.
855  bool KnownDependent;
856  if (LSI->NumExplicitTemplateParams > 0) {
857  auto *TemplateParamScope = CurScope->getTemplateParamParent();
858  assert(TemplateParamScope &&
859  "Lambda with explicit template param list should establish a "
860  "template param scope");
861  assert(TemplateParamScope->getParent());
862  KnownDependent = TemplateParamScope->getParent()
863  ->getTemplateParamParent() != nullptr;
864  } else {
865  KnownDependent = CurScope->getTemplateParamParent() != nullptr;
866  }
867 
868  // Determine the signature of the call operator.
869  TypeSourceInfo *MethodTyInfo;
870  bool ExplicitParams = true;
871  bool ExplicitResultType = true;
872  bool ContainsUnexpandedParameterPack = false;
873  SourceLocation EndLoc;
875  if (ParamInfo.getNumTypeObjects() == 0) {
876  // C++11 [expr.prim.lambda]p4:
877  // If a lambda-expression does not include a lambda-declarator, it is as
878  // if the lambda-declarator were ().
880  /*IsVariadic=*/false, /*IsCXXMethod=*/true));
881  EPI.HasTrailingReturn = true;
882  EPI.TypeQuals.addConst();
883  // C++1y [expr.prim.lambda]:
884  // The lambda return type is 'auto', which is replaced by the
885  // trailing-return type if provided and/or deduced from 'return'
886  // statements
887  // We don't do this before C++1y, because we don't support deduced return
888  // types there.
889  QualType DefaultTypeForNoTrailingReturn =
890  getLangOpts().CPlusPlus14 ? Context.getAutoDeductType()
891  : Context.DependentTy;
892  QualType MethodTy =
893  Context.getFunctionType(DefaultTypeForNoTrailingReturn, None, EPI);
894  MethodTyInfo = Context.getTrivialTypeSourceInfo(MethodTy);
895  ExplicitParams = false;
896  ExplicitResultType = false;
897  EndLoc = Intro.Range.getEnd();
898  } else {
899  assert(ParamInfo.isFunctionDeclarator() &&
900  "lambda-declarator is a function");
902 
903  // C++11 [expr.prim.lambda]p5:
904  // This function call operator is declared const (9.3.1) if and only if
905  // the lambda-expression's parameter-declaration-clause is not followed
906  // by mutable. It is neither virtual nor declared volatile. [...]
907  if (!FTI.hasMutableQualifier()) {
909  SourceLocation());
910  }
911 
912  MethodTyInfo = GetTypeForDeclarator(ParamInfo, CurScope);
913  assert(MethodTyInfo && "no type from lambda-declarator");
914  EndLoc = ParamInfo.getSourceRange().getEnd();
915 
916  ExplicitResultType = FTI.hasTrailingReturnType();
917 
918  if (FTIHasNonVoidParameters(FTI)) {
919  Params.reserve(FTI.NumParams);
920  for (unsigned i = 0, e = FTI.NumParams; i != e; ++i)
921  Params.push_back(cast<ParmVarDecl>(FTI.Params[i].Param));
922  }
923 
924  // Check for unexpanded parameter packs in the method type.
925  if (MethodTyInfo->getType()->containsUnexpandedParameterPack())
926  DiagnoseUnexpandedParameterPack(Intro.Range.getBegin(), MethodTyInfo,
927  UPPC_DeclarationType);
928  }
929 
930  CXXRecordDecl *Class = createLambdaClosureType(Intro.Range, MethodTyInfo,
931  KnownDependent, Intro.Default);
932  CXXMethodDecl *Method =
933  startLambdaDefinition(Class, Intro.Range, MethodTyInfo, EndLoc, Params,
934  ParamInfo.getDeclSpec().getConstexprSpecifier());
935  if (ExplicitParams)
936  CheckCXXDefaultArguments(Method);
937 
938  // This represents the function body for the lambda function, check if we
939  // have to apply optnone due to a pragma.
940  AddRangeBasedOptnone(Method);
941 
942  // code_seg attribute on lambda apply to the method.
943  if (Attr *A = getImplicitCodeSegOrSectionAttrForFunction(Method, /*IsDefinition=*/true))
944  Method->addAttr(A);
945 
946  // Attributes on the lambda apply to the method.
947  ProcessDeclAttributes(CurScope, Method, ParamInfo);
948 
949  // CUDA lambdas get implicit attributes based on the scope in which they're
950  // declared.
951  if (getLangOpts().CUDA)
952  CUDASetLambdaAttrs(Method);
953 
954  // Introduce the function call operator as the current declaration context.
955  PushDeclContext(CurScope, Method);
956 
957  // Build the lambda scope.
958  buildLambdaScope(LSI, Method, Intro.Range, Intro.Default, Intro.DefaultLoc,
959  ExplicitParams, ExplicitResultType, !Method->isConst());
960 
961  // C++11 [expr.prim.lambda]p9:
962  // A lambda-expression whose smallest enclosing scope is a block scope is a
963  // local lambda expression; any other lambda expression shall not have a
964  // capture-default or simple-capture in its lambda-introducer.
965  //
966  // For simple-captures, this is covered by the check below that any named
967  // entity is a variable that can be captured.
968  //
969  // For DR1632, we also allow a capture-default in any context where we can
970  // odr-use 'this' (in particular, in a default initializer for a non-static
971  // data member).
972  if (Intro.Default != LCD_None && !Class->getParent()->isFunctionOrMethod() &&
973  (getCurrentThisType().isNull() ||
974  CheckCXXThisCapture(SourceLocation(), /*Explicit*/true,
975  /*BuildAndDiagnose*/false)))
976  Diag(Intro.DefaultLoc, diag::err_capture_default_non_local);
977 
978  // Distinct capture names, for diagnostics.
979  llvm::SmallSet<IdentifierInfo*, 8> CaptureNames;
980 
981  // Handle explicit captures.
982  SourceLocation PrevCaptureLoc
983  = Intro.Default == LCD_None? Intro.Range.getBegin() : Intro.DefaultLoc;
984  for (auto C = Intro.Captures.begin(), E = Intro.Captures.end(); C != E;
985  PrevCaptureLoc = C->Loc, ++C) {
986  if (C->Kind == LCK_This || C->Kind == LCK_StarThis) {
987  if (C->Kind == LCK_StarThis)
988  Diag(C->Loc, !getLangOpts().CPlusPlus17
989  ? diag::ext_star_this_lambda_capture_cxx17
990  : diag::warn_cxx14_compat_star_this_lambda_capture);
991 
992  // C++11 [expr.prim.lambda]p8:
993  // An identifier or this shall not appear more than once in a
994  // lambda-capture.
995  if (LSI->isCXXThisCaptured()) {
996  Diag(C->Loc, diag::err_capture_more_than_once)
997  << "'this'" << SourceRange(LSI->getCXXThisCapture().getLocation())
999  SourceRange(getLocForEndOfToken(PrevCaptureLoc), C->Loc));
1000  continue;
1001  }
1002 
1003  // C++2a [expr.prim.lambda]p8:
1004  // If a lambda-capture includes a capture-default that is =,
1005  // each simple-capture of that lambda-capture shall be of the form
1006  // "&identifier", "this", or "* this". [ Note: The form [&,this] is
1007  // redundant but accepted for compatibility with ISO C++14. --end note ]
1008  if (Intro.Default == LCD_ByCopy && C->Kind != LCK_StarThis)
1009  Diag(C->Loc, !getLangOpts().CPlusPlus2a
1010  ? diag::ext_equals_this_lambda_capture_cxx2a
1011  : diag::warn_cxx17_compat_equals_this_lambda_capture);
1012 
1013  // C++11 [expr.prim.lambda]p12:
1014  // If this is captured by a local lambda expression, its nearest
1015  // enclosing function shall be a non-static member function.
1016  QualType ThisCaptureType = getCurrentThisType();
1017  if (ThisCaptureType.isNull()) {
1018  Diag(C->Loc, diag::err_this_capture) << true;
1019  continue;
1020  }
1021 
1022  CheckCXXThisCapture(C->Loc, /*Explicit=*/true, /*BuildAndDiagnose*/ true,
1023  /*FunctionScopeIndexToStopAtPtr*/ nullptr,
1024  C->Kind == LCK_StarThis);
1025  if (!LSI->Captures.empty())
1026  LSI->ExplicitCaptureRanges[LSI->Captures.size() - 1] = C->ExplicitRange;
1027  continue;
1028  }
1029 
1030  assert(C->Id && "missing identifier for capture");
1031 
1032  if (C->Init.isInvalid())
1033  continue;
1034 
1035  VarDecl *Var = nullptr;
1036  if (C->Init.isUsable()) {
1037  Diag(C->Loc, getLangOpts().CPlusPlus14
1038  ? diag::warn_cxx11_compat_init_capture
1039  : diag::ext_init_capture);
1040 
1041  // If the initializer expression is usable, but the InitCaptureType
1042  // is not, then an error has occurred - so ignore the capture for now.
1043  // for e.g., [n{0}] { }; <-- if no <initializer_list> is included.
1044  // FIXME: we should create the init capture variable and mark it invalid
1045  // in this case.
1046  if (C->InitCaptureType.get().isNull())
1047  continue;
1048 
1049  if (C->Init.get()->containsUnexpandedParameterPack() &&
1050  !C->InitCaptureType.get()->getAs<PackExpansionType>())
1051  DiagnoseUnexpandedParameterPack(C->Init.get(), UPPC_Initializer);
1052 
1053  unsigned InitStyle;
1054  switch (C->InitKind) {
1056  llvm_unreachable("not an init-capture?");
1058  InitStyle = VarDecl::CInit;
1059  break;
1061  InitStyle = VarDecl::CallInit;
1062  break;
1064  InitStyle = VarDecl::ListInit;
1065  break;
1066  }
1067  Var = createLambdaInitCaptureVarDecl(C->Loc, C->InitCaptureType.get(),
1068  C->EllipsisLoc, C->Id, InitStyle,
1069  C->Init.get());
1070  // C++1y [expr.prim.lambda]p11:
1071  // An init-capture behaves as if it declares and explicitly
1072  // captures a variable [...] whose declarative region is the
1073  // lambda-expression's compound-statement
1074  if (Var)
1075  PushOnScopeChains(Var, CurScope, false);
1076  } else {
1077  assert(C->InitKind == LambdaCaptureInitKind::NoInit &&
1078  "init capture has valid but null init?");
1079 
1080  // C++11 [expr.prim.lambda]p8:
1081  // If a lambda-capture includes a capture-default that is &, the
1082  // identifiers in the lambda-capture shall not be preceded by &.
1083  // If a lambda-capture includes a capture-default that is =, [...]
1084  // each identifier it contains shall be preceded by &.
1085  if (C->Kind == LCK_ByRef && Intro.Default == LCD_ByRef) {
1086  Diag(C->Loc, diag::err_reference_capture_with_reference_default)
1088  SourceRange(getLocForEndOfToken(PrevCaptureLoc), C->Loc));
1089  continue;
1090  } else if (C->Kind == LCK_ByCopy && Intro.Default == LCD_ByCopy) {
1091  Diag(C->Loc, diag::err_copy_capture_with_copy_default)
1093  SourceRange(getLocForEndOfToken(PrevCaptureLoc), C->Loc));
1094  continue;
1095  }
1096 
1097  // C++11 [expr.prim.lambda]p10:
1098  // The identifiers in a capture-list are looked up using the usual
1099  // rules for unqualified name lookup (3.4.1)
1100  DeclarationNameInfo Name(C->Id, C->Loc);
1101  LookupResult R(*this, Name, LookupOrdinaryName);
1102  LookupName(R, CurScope);
1103  if (R.isAmbiguous())
1104  continue;
1105  if (R.empty()) {
1106  // FIXME: Disable corrections that would add qualification?
1107  CXXScopeSpec ScopeSpec;
1108  DeclFilterCCC<VarDecl> Validator{};
1109  if (DiagnoseEmptyLookup(CurScope, ScopeSpec, R, Validator))
1110  continue;
1111  }
1112 
1113  Var = R.getAsSingle<VarDecl>();
1114  if (Var && DiagnoseUseOfDecl(Var, C->Loc))
1115  continue;
1116  }
1117 
1118  // C++11 [expr.prim.lambda]p8:
1119  // An identifier or this shall not appear more than once in a
1120  // lambda-capture.
1121  if (!CaptureNames.insert(C->Id).second) {
1122  if (Var && LSI->isCaptured(Var)) {
1123  Diag(C->Loc, diag::err_capture_more_than_once)
1124  << C->Id << SourceRange(LSI->getCapture(Var).getLocation())
1126  SourceRange(getLocForEndOfToken(PrevCaptureLoc), C->Loc));
1127  } else
1128  // Previous capture captured something different (one or both was
1129  // an init-cpature): no fixit.
1130  Diag(C->Loc, diag::err_capture_more_than_once) << C->Id;
1131  continue;
1132  }
1133 
1134  // C++11 [expr.prim.lambda]p10:
1135  // [...] each such lookup shall find a variable with automatic storage
1136  // duration declared in the reaching scope of the local lambda expression.
1137  // Note that the 'reaching scope' check happens in tryCaptureVariable().
1138  if (!Var) {
1139  Diag(C->Loc, diag::err_capture_does_not_name_variable) << C->Id;
1140  continue;
1141  }
1142 
1143  // Ignore invalid decls; they'll just confuse the code later.
1144  if (Var->isInvalidDecl())
1145  continue;
1146 
1147  if (!Var->hasLocalStorage()) {
1148  Diag(C->Loc, diag::err_capture_non_automatic_variable) << C->Id;
1149  Diag(Var->getLocation(), diag::note_previous_decl) << C->Id;
1150  continue;
1151  }
1152 
1153  // C++11 [expr.prim.lambda]p23:
1154  // A capture followed by an ellipsis is a pack expansion (14.5.3).
1155  SourceLocation EllipsisLoc;
1156  if (C->EllipsisLoc.isValid()) {
1157  if (Var->isParameterPack()) {
1158  EllipsisLoc = C->EllipsisLoc;
1159  } else {
1160  Diag(C->EllipsisLoc, diag::err_pack_expansion_without_parameter_packs)
1161  << (C->Init.isUsable() ? C->Init.get()->getSourceRange()
1162  : SourceRange(C->Loc));
1163 
1164  // Just ignore the ellipsis.
1165  }
1166  } else if (Var->isParameterPack()) {
1167  ContainsUnexpandedParameterPack = true;
1168  }
1169 
1170  if (C->Init.isUsable()) {
1171  addInitCapture(LSI, Var);
1172  } else {
1173  TryCaptureKind Kind = C->Kind == LCK_ByRef ? TryCapture_ExplicitByRef :
1174  TryCapture_ExplicitByVal;
1175  tryCaptureVariable(Var, C->Loc, Kind, EllipsisLoc);
1176  }
1177  if (!LSI->Captures.empty())
1178  LSI->ExplicitCaptureRanges[LSI->Captures.size() - 1] = C->ExplicitRange;
1179  }
1180  finishLambdaExplicitCaptures(LSI);
1181 
1182  LSI->ContainsUnexpandedParameterPack |= ContainsUnexpandedParameterPack;
1183 
1184  // Add lambda parameters into scope.
1185  addLambdaParameters(Intro.Captures, Method, CurScope);
1186 
1187  // Enter a new evaluation context to insulate the lambda from any
1188  // cleanups from the enclosing full-expression.
1189  PushExpressionEvaluationContext(
1190  ExpressionEvaluationContext::PotentiallyEvaluated);
1191 }
1192 
1194  bool IsInstantiation) {
1195  LambdaScopeInfo *LSI = cast<LambdaScopeInfo>(FunctionScopes.back());
1196 
1197  // Leave the expression-evaluation context.
1198  DiscardCleanupsInEvaluationContext();
1199  PopExpressionEvaluationContext();
1200 
1201  // Leave the context of the lambda.
1202  if (!IsInstantiation)
1203  PopDeclContext();
1204 
1205  // Finalize the lambda.
1206  CXXRecordDecl *Class = LSI->Lambda;
1207  Class->setInvalidDecl();
1208  SmallVector<Decl*, 4> Fields(Class->fields());
1209  ActOnFields(nullptr, Class->getLocation(), Class, Fields, SourceLocation(),
1211  CheckCompletedCXXClass(Class);
1212 
1213  PopFunctionScopeInfo();
1214 }
1215 
1217  const FunctionProtoType *CallOpProto) {
1218  // The function type inside the pointer type is the same as the call
1219  // operator with some tweaks. The calling convention is the default free
1220  // function convention, and the type qualifications are lost.
1221  const FunctionProtoType::ExtProtoInfo CallOpExtInfo =
1222  CallOpProto->getExtProtoInfo();
1223  FunctionProtoType::ExtProtoInfo InvokerExtInfo = CallOpExtInfo;
1225  CallOpProto->isVariadic(), /*IsCXXMethod=*/false);
1226  InvokerExtInfo.ExtInfo = InvokerExtInfo.ExtInfo.withCallingConv(CC);
1227  InvokerExtInfo.TypeQuals = Qualifiers();
1228  assert(InvokerExtInfo.RefQualifier == RQ_None &&
1229  "Lambda's call operator should not have a reference qualifier");
1230  return Context.getFunctionType(CallOpProto->getReturnType(),
1231  CallOpProto->getParamTypes(), InvokerExtInfo);
1232 }
1233 
1234 /// Add a lambda's conversion to function pointer, as described in
1235 /// C++11 [expr.prim.lambda]p6.
1237  SourceRange IntroducerRange,
1238  CXXRecordDecl *Class,
1239  CXXMethodDecl *CallOperator) {
1240  // This conversion is explicitly disabled if the lambda's function has
1241  // pass_object_size attributes on any of its parameters.
1242  auto HasPassObjectSizeAttr = [](const ParmVarDecl *P) {
1243  return P->hasAttr<PassObjectSizeAttr>();
1244  };
1245  if (llvm::any_of(CallOperator->parameters(), HasPassObjectSizeAttr))
1246  return;
1247 
1248  // Add the conversion to function pointer.
1249  QualType InvokerFunctionTy = S.getLambdaConversionFunctionResultType(
1250  CallOperator->getType()->castAs<FunctionProtoType>());
1251  QualType PtrToFunctionTy = S.Context.getPointerType(InvokerFunctionTy);
1252 
1253  // Create the type of the conversion function.
1254  FunctionProtoType::ExtProtoInfo ConvExtInfo(
1256  /*IsVariadic=*/false, /*IsCXXMethod=*/true));
1257  // The conversion function is always const and noexcept.
1258  ConvExtInfo.TypeQuals = Qualifiers();
1259  ConvExtInfo.TypeQuals.addConst();
1260  ConvExtInfo.ExceptionSpec.Type = EST_BasicNoexcept;
1261  QualType ConvTy =
1262  S.Context.getFunctionType(PtrToFunctionTy, None, ConvExtInfo);
1263 
1264  SourceLocation Loc = IntroducerRange.getBegin();
1265  DeclarationName ConversionName
1267  S.Context.getCanonicalType(PtrToFunctionTy));
1268  DeclarationNameLoc ConvNameLoc;
1269  // Construct a TypeSourceInfo for the conversion function, and wire
1270  // all the parameters appropriately for the FunctionProtoTypeLoc
1271  // so that everything works during transformation/instantiation of
1272  // generic lambdas.
1273  // The main reason for wiring up the parameters of the conversion
1274  // function with that of the call operator is so that constructs
1275  // like the following work:
1276  // auto L = [](auto b) { <-- 1
1277  // return [](auto a) -> decltype(a) { <-- 2
1278  // return a;
1279  // };
1280  // };
1281  // int (*fp)(int) = L(5);
1282  // Because the trailing return type can contain DeclRefExprs that refer
1283  // to the original call operator's variables, we hijack the call
1284  // operators ParmVarDecls below.
1285  TypeSourceInfo *ConvNamePtrToFunctionTSI =
1286  S.Context.getTrivialTypeSourceInfo(PtrToFunctionTy, Loc);
1287  ConvNameLoc.NamedType.TInfo = ConvNamePtrToFunctionTSI;
1288 
1289  // The conversion function is a conversion to a pointer-to-function.
1290  TypeSourceInfo *ConvTSI = S.Context.getTrivialTypeSourceInfo(ConvTy, Loc);
1291  FunctionProtoTypeLoc ConvTL =
1292  ConvTSI->getTypeLoc().getAs<FunctionProtoTypeLoc>();
1293  // Get the result of the conversion function which is a pointer-to-function.
1294  PointerTypeLoc PtrToFunctionTL =
1295  ConvTL.getReturnLoc().getAs<PointerTypeLoc>();
1296  // Do the same for the TypeSourceInfo that is used to name the conversion
1297  // operator.
1298  PointerTypeLoc ConvNamePtrToFunctionTL =
1299  ConvNamePtrToFunctionTSI->getTypeLoc().getAs<PointerTypeLoc>();
1300 
1301  // Get the underlying function types that the conversion function will
1302  // be converting to (should match the type of the call operator).
1303  FunctionProtoTypeLoc CallOpConvTL =
1304  PtrToFunctionTL.getPointeeLoc().getAs<FunctionProtoTypeLoc>();
1305  FunctionProtoTypeLoc CallOpConvNameTL =
1306  ConvNamePtrToFunctionTL.getPointeeLoc().getAs<FunctionProtoTypeLoc>();
1307 
1308  // Wire up the FunctionProtoTypeLocs with the call operator's parameters.
1309  // These parameter's are essentially used to transform the name and
1310  // the type of the conversion operator. By using the same parameters
1311  // as the call operator's we don't have to fix any back references that
1312  // the trailing return type of the call operator's uses (such as
1313  // decltype(some_type<decltype(a)>::type{} + decltype(a){}) etc.)
1314  // - we can simply use the return type of the call operator, and
1315  // everything should work.
1316  SmallVector<ParmVarDecl *, 4> InvokerParams;
1317  for (unsigned I = 0, N = CallOperator->getNumParams(); I != N; ++I) {
1318  ParmVarDecl *From = CallOperator->getParamDecl(I);
1319 
1320  InvokerParams.push_back(ParmVarDecl::Create(
1321  S.Context,
1322  // Temporarily add to the TU. This is set to the invoker below.
1324  From->getLocation(), From->getIdentifier(), From->getType(),
1325  From->getTypeSourceInfo(), From->getStorageClass(),
1326  /*DefArg=*/nullptr));
1327  CallOpConvTL.setParam(I, From);
1328  CallOpConvNameTL.setParam(I, From);
1329  }
1330 
1332  S.Context, Class, Loc,
1333  DeclarationNameInfo(ConversionName, Loc, ConvNameLoc), ConvTy, ConvTSI,
1334  /*isInline=*/true, ExplicitSpecifier(),
1335  S.getLangOpts().CPlusPlus17 ? CSK_constexpr : CSK_unspecified,
1336  CallOperator->getBody()->getEndLoc());
1337  Conversion->setAccess(AS_public);
1338  Conversion->setImplicit(true);
1339 
1340  if (Class->isGenericLambda()) {
1341  // Create a template version of the conversion operator, using the template
1342  // parameter list of the function call operator.
1343  FunctionTemplateDecl *TemplateCallOperator =
1344  CallOperator->getDescribedFunctionTemplate();
1345  FunctionTemplateDecl *ConversionTemplate =
1347  Loc, ConversionName,
1348  TemplateCallOperator->getTemplateParameters(),
1349  Conversion);
1350  ConversionTemplate->setAccess(AS_public);
1351  ConversionTemplate->setImplicit(true);
1352  Conversion->setDescribedFunctionTemplate(ConversionTemplate);
1353  Class->addDecl(ConversionTemplate);
1354  } else
1355  Class->addDecl(Conversion);
1356  // Add a non-static member function that will be the result of
1357  // the conversion with a certain unique ID.
1358  DeclarationName InvokerName = &S.Context.Idents.get(
1360  // FIXME: Instead of passing in the CallOperator->getTypeSourceInfo()
1361  // we should get a prebuilt TrivialTypeSourceInfo from Context
1362  // using FunctionTy & Loc and get its TypeLoc as a FunctionProtoTypeLoc
1363  // then rewire the parameters accordingly, by hoisting up the InvokeParams
1364  // loop below and then use its Params to set Invoke->setParams(...) below.
1365  // This would avoid the 'const' qualifier of the calloperator from
1366  // contaminating the type of the invoker, which is currently adjusted
1367  // in SemaTemplateDeduction.cpp:DeduceTemplateArguments. Fixing the
1368  // trailing return type of the invoker would require a visitor to rebuild
1369  // the trailing return type and adjusting all back DeclRefExpr's to refer
1370  // to the new static invoker parameters - not the call operator's.
1372  S.Context, Class, Loc, DeclarationNameInfo(InvokerName, Loc),
1373  InvokerFunctionTy, CallOperator->getTypeSourceInfo(), SC_Static,
1374  /*isInline=*/true, CSK_unspecified, CallOperator->getBody()->getEndLoc());
1375  for (unsigned I = 0, N = CallOperator->getNumParams(); I != N; ++I)
1376  InvokerParams[I]->setOwningFunction(Invoke);
1377  Invoke->setParams(InvokerParams);
1378  Invoke->setAccess(AS_private);
1379  Invoke->setImplicit(true);
1380  if (Class->isGenericLambda()) {
1381  FunctionTemplateDecl *TemplateCallOperator =
1382  CallOperator->getDescribedFunctionTemplate();
1383  FunctionTemplateDecl *StaticInvokerTemplate = FunctionTemplateDecl::Create(
1384  S.Context, Class, Loc, InvokerName,
1385  TemplateCallOperator->getTemplateParameters(),
1386  Invoke);
1387  StaticInvokerTemplate->setAccess(AS_private);
1388  StaticInvokerTemplate->setImplicit(true);
1389  Invoke->setDescribedFunctionTemplate(StaticInvokerTemplate);
1390  Class->addDecl(StaticInvokerTemplate);
1391  } else
1392  Class->addDecl(Invoke);
1393 }
1394 
1395 /// Add a lambda's conversion to block pointer.
1397  SourceRange IntroducerRange,
1398  CXXRecordDecl *Class,
1399  CXXMethodDecl *CallOperator) {
1401  CallOperator->getType()->castAs<FunctionProtoType>());
1402  QualType BlockPtrTy = S.Context.getBlockPointerType(FunctionTy);
1403 
1404  FunctionProtoType::ExtProtoInfo ConversionEPI(
1406  /*IsVariadic=*/false, /*IsCXXMethod=*/true));
1407  ConversionEPI.TypeQuals = Qualifiers();
1408  ConversionEPI.TypeQuals.addConst();
1409  QualType ConvTy = S.Context.getFunctionType(BlockPtrTy, None, ConversionEPI);
1410 
1411  SourceLocation Loc = IntroducerRange.getBegin();
1412  DeclarationName Name
1414  S.Context.getCanonicalType(BlockPtrTy));
1415  DeclarationNameLoc NameLoc;
1416  NameLoc.NamedType.TInfo = S.Context.getTrivialTypeSourceInfo(BlockPtrTy, Loc);
1418  S.Context, Class, Loc, DeclarationNameInfo(Name, Loc, NameLoc), ConvTy,
1419  S.Context.getTrivialTypeSourceInfo(ConvTy, Loc),
1420  /*isInline=*/true, ExplicitSpecifier(), CSK_unspecified,
1421  CallOperator->getBody()->getEndLoc());
1422  Conversion->setAccess(AS_public);
1423  Conversion->setImplicit(true);
1424  Class->addDecl(Conversion);
1425 }
1426 
1428  SourceLocation ImplicitCaptureLoc,
1429  bool IsOpenMPMapping) {
1430  // VLA captures don't have a stored initialization expression.
1431  if (Cap.isVLATypeCapture())
1432  return ExprResult();
1433 
1434  // An init-capture is initialized directly from its stored initializer.
1435  if (Cap.isInitCapture())
1436  return Cap.getVariable()->getInit();
1437 
1438  // For anything else, build an initialization expression. For an implicit
1439  // capture, the capture notionally happens at the capture-default, so use
1440  // that location here.
1441  SourceLocation Loc =
1442  ImplicitCaptureLoc.isValid() ? ImplicitCaptureLoc : Cap.getLocation();
1443 
1444  // C++11 [expr.prim.lambda]p21:
1445  // When the lambda-expression is evaluated, the entities that
1446  // are captured by copy are used to direct-initialize each
1447  // corresponding non-static data member of the resulting closure
1448  // object. (For array members, the array elements are
1449  // direct-initialized in increasing subscript order.) These
1450  // initializations are performed in the (unspecified) order in
1451  // which the non-static data members are declared.
1452 
1453  // C++ [expr.prim.lambda]p12:
1454  // An entity captured by a lambda-expression is odr-used (3.2) in
1455  // the scope containing the lambda-expression.
1456  ExprResult Init;
1457  IdentifierInfo *Name = nullptr;
1458  if (Cap.isThisCapture()) {
1459  QualType ThisTy = getCurrentThisType();
1460  Expr *This = BuildCXXThisExpr(Loc, ThisTy, ImplicitCaptureLoc.isValid());
1461  if (Cap.isCopyCapture())
1462  Init = CreateBuiltinUnaryOp(Loc, UO_Deref, This);
1463  else
1464  Init = This;
1465  } else {
1466  assert(Cap.isVariableCapture() && "unknown kind of capture");
1467  VarDecl *Var = Cap.getVariable();
1468  Name = Var->getIdentifier();
1469  Init = BuildDeclarationNameExpr(
1470  CXXScopeSpec(), DeclarationNameInfo(Var->getDeclName(), Loc), Var);
1471  }
1472 
1473  // In OpenMP, the capture kind doesn't actually describe how to capture:
1474  // variables are "mapped" onto the device in a process that does not formally
1475  // make a copy, even for a "copy capture".
1476  if (IsOpenMPMapping)
1477  return Init;
1478 
1479  if (Init.isInvalid())
1480  return ExprError();
1481 
1482  Expr *InitExpr = Init.get();
1484  Name, Cap.getCaptureType(), Loc);
1485  InitializationKind InitKind =
1486  InitializationKind::CreateDirect(Loc, Loc, Loc);
1487  InitializationSequence InitSeq(*this, Entity, InitKind, InitExpr);
1488  return InitSeq.Perform(*this, Entity, InitKind, InitExpr);
1489 }
1490 
1492  Scope *CurScope) {
1493  LambdaScopeInfo LSI = *cast<LambdaScopeInfo>(FunctionScopes.back());
1494  ActOnFinishFunctionBody(LSI.CallOperator, Body);
1495  return BuildLambdaExpr(StartLoc, Body->getEndLoc(), &LSI);
1496 }
1497 
1498 static LambdaCaptureDefault
1500  switch (ICS) {
1502  return LCD_None;
1504  return LCD_ByCopy;
1507  return LCD_ByRef;
1509  llvm_unreachable("block capture in lambda");
1510  }
1511  llvm_unreachable("Unknown implicit capture style");
1512 }
1513 
1515  if (From.isInitCapture()) {
1516  Expr *Init = From.getVariable()->getInit();
1517  if (Init && Init->HasSideEffects(Context))
1518  return true;
1519  }
1520 
1521  if (!From.isCopyCapture())
1522  return false;
1523 
1524  const QualType T = From.isThisCapture()
1525  ? getCurrentThisType()->getPointeeType()
1526  : From.getCaptureType();
1527 
1528  if (T.isVolatileQualified())
1529  return true;
1530 
1531  const Type *BaseT = T->getBaseElementTypeUnsafe();
1532  if (const CXXRecordDecl *RD = BaseT->getAsCXXRecordDecl())
1533  return !RD->isCompleteDefinition() || !RD->hasTrivialCopyConstructor() ||
1534  !RD->hasTrivialDestructor();
1535 
1536  return false;
1537 }
1538 
1540  const Capture &From) {
1541  if (CaptureHasSideEffects(From))
1542  return false;
1543 
1544  if (From.isVLATypeCapture())
1545  return false;
1546 
1547  auto diag = Diag(From.getLocation(), diag::warn_unused_lambda_capture);
1548  if (From.isThisCapture())
1549  diag << "'this'";
1550  else
1551  diag << From.getVariable();
1552  diag << From.isNonODRUsed();
1553  diag << FixItHint::CreateRemoval(CaptureRange);
1554  return true;
1555 }
1556 
1557 /// Create a field within the lambda class or captured statement record for the
1558 /// given capture.
1560  const sema::Capture &Capture) {
1561  SourceLocation Loc = Capture.getLocation();
1562  QualType FieldType = Capture.getCaptureType();
1563 
1564  TypeSourceInfo *TSI = nullptr;
1565  if (Capture.isVariableCapture()) {
1566  auto *Var = Capture.getVariable();
1567  if (Var->isInitCapture())
1568  TSI = Capture.getVariable()->getTypeSourceInfo();
1569  }
1570 
1571  // FIXME: Should we really be doing this? A null TypeSourceInfo seems more
1572  // appropriate, at least for an implicit capture.
1573  if (!TSI)
1574  TSI = Context.getTrivialTypeSourceInfo(FieldType, Loc);
1575 
1576  // Build the non-static data member.
1577  FieldDecl *Field =
1578  FieldDecl::Create(Context, RD, Loc, Loc, nullptr, FieldType, TSI, nullptr,
1579  false, ICIS_NoInit);
1580  // If the variable being captured has an invalid type, mark the class as
1581  // invalid as well.
1582  if (!FieldType->isDependentType()) {
1583  if (RequireCompleteType(Loc, FieldType, diag::err_field_incomplete)) {
1584  RD->setInvalidDecl();
1585  Field->setInvalidDecl();
1586  } else {
1587  NamedDecl *Def;
1588  FieldType->isIncompleteType(&Def);
1589  if (Def && Def->isInvalidDecl()) {
1590  RD->setInvalidDecl();
1591  Field->setInvalidDecl();
1592  }
1593  }
1594  }
1595  Field->setImplicit(true);
1596  Field->setAccess(AS_private);
1597  RD->addDecl(Field);
1598 
1599  if (Capture.isVLATypeCapture())
1600  Field->setCapturedVLAType(Capture.getCapturedVLAType());
1601 
1602  return Field;
1603 }
1604 
1606  LambdaScopeInfo *LSI) {
1607  // Collect information from the lambda scope.
1609  SmallVector<Expr *, 4> CaptureInits;
1610  SourceLocation CaptureDefaultLoc = LSI->CaptureDefaultLoc;
1611  LambdaCaptureDefault CaptureDefault =
1613  CXXRecordDecl *Class;
1614  CXXMethodDecl *CallOperator;
1615  SourceRange IntroducerRange;
1616  bool ExplicitParams;
1617  bool ExplicitResultType;
1618  CleanupInfo LambdaCleanup;
1619  bool ContainsUnexpandedParameterPack;
1620  bool IsGenericLambda;
1621  {
1622  CallOperator = LSI->CallOperator;
1623  Class = LSI->Lambda;
1624  IntroducerRange = LSI->IntroducerRange;
1625  ExplicitParams = LSI->ExplicitParams;
1626  ExplicitResultType = !LSI->HasImplicitReturnType;
1627  LambdaCleanup = LSI->Cleanup;
1628  ContainsUnexpandedParameterPack = LSI->ContainsUnexpandedParameterPack;
1629  IsGenericLambda = Class->isGenericLambda();
1630 
1631  CallOperator->setLexicalDeclContext(Class);
1632  Decl *TemplateOrNonTemplateCallOperatorDecl =
1633  CallOperator->getDescribedFunctionTemplate()
1634  ? CallOperator->getDescribedFunctionTemplate()
1635  : cast<Decl>(CallOperator);
1636 
1637  // FIXME: Is this really the best choice? Keeping the lexical decl context
1638  // set as CurContext seems more faithful to the source.
1639  TemplateOrNonTemplateCallOperatorDecl->setLexicalDeclContext(Class);
1640 
1641  PopExpressionEvaluationContext();
1642 
1643  // True if the current capture has a used capture or default before it.
1644  bool CurHasPreviousCapture = CaptureDefault != LCD_None;
1645  SourceLocation PrevCaptureLoc = CurHasPreviousCapture ?
1646  CaptureDefaultLoc : IntroducerRange.getBegin();
1647 
1648  for (unsigned I = 0, N = LSI->Captures.size(); I != N; ++I) {
1649  const Capture &From = LSI->Captures[I];
1650 
1651  if (From.isInvalid())
1652  return ExprError();
1653 
1654  assert(!From.isBlockCapture() && "Cannot capture __block variables");
1655  bool IsImplicit = I >= LSI->NumExplicitCaptures;
1656  SourceLocation ImplicitCaptureLoc =
1657  IsImplicit ? CaptureDefaultLoc : SourceLocation();
1658 
1659  // Use source ranges of explicit captures for fixits where available.
1660  SourceRange CaptureRange = LSI->ExplicitCaptureRanges[I];
1661 
1662  // Warn about unused explicit captures.
1663  bool IsCaptureUsed = true;
1664  if (!CurContext->isDependentContext() && !IsImplicit &&
1665  !From.isODRUsed()) {
1666  // Initialized captures that are non-ODR used may not be eliminated.
1667  // FIXME: Where did the IsGenericLambda here come from?
1668  bool NonODRUsedInitCapture =
1669  IsGenericLambda && From.isNonODRUsed() && From.isInitCapture();
1670  if (!NonODRUsedInitCapture) {
1671  bool IsLast = (I + 1) == LSI->NumExplicitCaptures;
1672  SourceRange FixItRange;
1673  if (CaptureRange.isValid()) {
1674  if (!CurHasPreviousCapture && !IsLast) {
1675  // If there are no captures preceding this capture, remove the
1676  // following comma.
1677  FixItRange = SourceRange(CaptureRange.getBegin(),
1678  getLocForEndOfToken(CaptureRange.getEnd()));
1679  } else {
1680  // Otherwise, remove the comma since the last used capture.
1681  FixItRange = SourceRange(getLocForEndOfToken(PrevCaptureLoc),
1682  CaptureRange.getEnd());
1683  }
1684  }
1685 
1686  IsCaptureUsed = !DiagnoseUnusedLambdaCapture(FixItRange, From);
1687  }
1688  }
1689 
1690  if (CaptureRange.isValid()) {
1691  CurHasPreviousCapture |= IsCaptureUsed;
1692  PrevCaptureLoc = CaptureRange.getEnd();
1693  }
1694 
1695  // Map the capture to our AST representation.
1696  LambdaCapture Capture = [&] {
1697  if (From.isThisCapture()) {
1698  // Capturing 'this' implicitly with a default of '[=]' is deprecated,
1699  // because it results in a reference capture. Don't warn prior to
1700  // C++2a; there's nothing that can be done about it before then.
1701  if (getLangOpts().CPlusPlus2a && IsImplicit &&
1702  CaptureDefault == LCD_ByCopy) {
1703  Diag(From.getLocation(), diag::warn_deprecated_this_capture);
1704  Diag(CaptureDefaultLoc, diag::note_deprecated_this_capture)
1706  getLocForEndOfToken(CaptureDefaultLoc), ", this");
1707  }
1708  return LambdaCapture(From.getLocation(), IsImplicit,
1709  From.isCopyCapture() ? LCK_StarThis : LCK_This);
1710  } else if (From.isVLATypeCapture()) {
1711  return LambdaCapture(From.getLocation(), IsImplicit, LCK_VLAType);
1712  } else {
1713  assert(From.isVariableCapture() && "unknown kind of capture");
1714  VarDecl *Var = From.getVariable();
1716  From.isCopyCapture() ? LCK_ByCopy : LCK_ByRef;
1717  return LambdaCapture(From.getLocation(), IsImplicit, Kind, Var,
1718  From.getEllipsisLoc());
1719  }
1720  }();
1721 
1722  // Form the initializer for the capture field.
1723  ExprResult Init = BuildCaptureInit(From, ImplicitCaptureLoc);
1724 
1725  // FIXME: Skip this capture if the capture is not used, the initializer
1726  // has no side-effects, the type of the capture is trivial, and the
1727  // lambda is not externally visible.
1728 
1729  // Add a FieldDecl for the capture and form its initializer.
1730  BuildCaptureField(Class, From);
1731  Captures.push_back(Capture);
1732  CaptureInits.push_back(Init.get());
1733  }
1734 
1735  // C++11 [expr.prim.lambda]p6:
1736  // The closure type for a lambda-expression with no lambda-capture
1737  // has a public non-virtual non-explicit const conversion function
1738  // to pointer to function having the same parameter and return
1739  // types as the closure type's function call operator.
1740  if (Captures.empty() && CaptureDefault == LCD_None)
1741  addFunctionPointerConversion(*this, IntroducerRange, Class,
1742  CallOperator);
1743 
1744  // Objective-C++:
1745  // The closure type for a lambda-expression has a public non-virtual
1746  // non-explicit const conversion function to a block pointer having the
1747  // same parameter and return types as the closure type's function call
1748  // operator.
1749  // FIXME: Fix generic lambda to block conversions.
1750  if (getLangOpts().Blocks && getLangOpts().ObjC && !IsGenericLambda)
1751  addBlockPointerConversion(*this, IntroducerRange, Class, CallOperator);
1752 
1753  // Finalize the lambda class.
1754  SmallVector<Decl*, 4> Fields(Class->fields());
1755  ActOnFields(nullptr, Class->getLocation(), Class, Fields, SourceLocation(),
1757  CheckCompletedCXXClass(Class);
1758  }
1759 
1760  Cleanup.mergeFrom(LambdaCleanup);
1761 
1762  LambdaExpr *Lambda = LambdaExpr::Create(Context, Class, IntroducerRange,
1763  CaptureDefault, CaptureDefaultLoc,
1764  Captures,
1765  ExplicitParams, ExplicitResultType,
1766  CaptureInits, EndLoc,
1767  ContainsUnexpandedParameterPack);
1768  // If the lambda expression's call operator is not explicitly marked constexpr
1769  // and we are not in a dependent context, analyze the call operator to infer
1770  // its constexpr-ness, suppressing diagnostics while doing so.
1771  if (getLangOpts().CPlusPlus17 && !CallOperator->isInvalidDecl() &&
1772  !CallOperator->isConstexpr() &&
1773  !isa<CoroutineBodyStmt>(CallOperator->getBody()) &&
1774  !Class->getDeclContext()->isDependentContext()) {
1775  CallOperator->setConstexprKind(
1776  CheckConstexprFunctionDefinition(CallOperator,
1777  CheckConstexprKind::CheckValid)
1778  ? CSK_constexpr
1779  : CSK_unspecified);
1780  }
1781 
1782  // Emit delayed shadowing warnings now that the full capture list is known.
1783  DiagnoseShadowingLambdaDecls(LSI);
1784 
1785  if (!CurContext->isDependentContext()) {
1786  switch (ExprEvalContexts.back().Context) {
1787  // C++11 [expr.prim.lambda]p2:
1788  // A lambda-expression shall not appear in an unevaluated operand
1789  // (Clause 5).
1790  case ExpressionEvaluationContext::Unevaluated:
1791  case ExpressionEvaluationContext::UnevaluatedList:
1792  case ExpressionEvaluationContext::UnevaluatedAbstract:
1793  // C++1y [expr.const]p2:
1794  // A conditional-expression e is a core constant expression unless the
1795  // evaluation of e, following the rules of the abstract machine, would
1796  // evaluate [...] a lambda-expression.
1797  //
1798  // This is technically incorrect, there are some constant evaluated contexts
1799  // where this should be allowed. We should probably fix this when DR1607 is
1800  // ratified, it lays out the exact set of conditions where we shouldn't
1801  // allow a lambda-expression.
1802  case ExpressionEvaluationContext::ConstantEvaluated:
1803  // We don't actually diagnose this case immediately, because we
1804  // could be within a context where we might find out later that
1805  // the expression is potentially evaluated (e.g., for typeid).
1806  ExprEvalContexts.back().Lambdas.push_back(Lambda);
1807  break;
1808 
1809  case ExpressionEvaluationContext::DiscardedStatement:
1810  case ExpressionEvaluationContext::PotentiallyEvaluated:
1811  case ExpressionEvaluationContext::PotentiallyEvaluatedIfUsed:
1812  break;
1813  }
1814  }
1815 
1816  return MaybeBindToTemporary(Lambda);
1817 }
1818 
1820  SourceLocation ConvLocation,
1821  CXXConversionDecl *Conv,
1822  Expr *Src) {
1823  // Make sure that the lambda call operator is marked used.
1824  CXXRecordDecl *Lambda = Conv->getParent();
1825  CXXMethodDecl *CallOperator
1826  = cast<CXXMethodDecl>(
1827  Lambda->lookup(
1828  Context.DeclarationNames.getCXXOperatorName(OO_Call)).front());
1829  CallOperator->setReferenced();
1830  CallOperator->markUsed(Context);
1831 
1832  ExprResult Init = PerformCopyInitialization(
1834  /*NRVO=*/false),
1835  CurrentLocation, Src);
1836  if (!Init.isInvalid())
1837  Init = ActOnFinishFullExpr(Init.get(), /*DiscardedValue*/ false);
1838 
1839  if (Init.isInvalid())
1840  return ExprError();
1841 
1842  // Create the new block to be returned.
1843  BlockDecl *Block = BlockDecl::Create(Context, CurContext, ConvLocation);
1844 
1845  // Set the type information.
1846  Block->setSignatureAsWritten(CallOperator->getTypeSourceInfo());
1847  Block->setIsVariadic(CallOperator->isVariadic());
1848  Block->setBlockMissingReturnType(false);
1849 
1850  // Add parameters.
1851  SmallVector<ParmVarDecl *, 4> BlockParams;
1852  for (unsigned I = 0, N = CallOperator->getNumParams(); I != N; ++I) {
1853  ParmVarDecl *From = CallOperator->getParamDecl(I);
1854  BlockParams.push_back(ParmVarDecl::Create(
1855  Context, Block, From->getBeginLoc(), From->getLocation(),
1856  From->getIdentifier(), From->getType(), From->getTypeSourceInfo(),
1857  From->getStorageClass(),
1858  /*DefArg=*/nullptr));
1859  }
1860  Block->setParams(BlockParams);
1861 
1862  Block->setIsConversionFromLambda(true);
1863 
1864  // Add capture. The capture uses a fake variable, which doesn't correspond
1865  // to any actual memory location. However, the initializer copy-initializes
1866  // the lambda object.
1867  TypeSourceInfo *CapVarTSI =
1868  Context.getTrivialTypeSourceInfo(Src->getType());
1869  VarDecl *CapVar = VarDecl::Create(Context, Block, ConvLocation,
1870  ConvLocation, nullptr,
1871  Src->getType(), CapVarTSI,
1872  SC_None);
1873  BlockDecl::Capture Capture(/*variable=*/CapVar, /*byRef=*/false,
1874  /*nested=*/false, /*copy=*/Init.get());
1875  Block->setCaptures(Context, Capture, /*CapturesCXXThis=*/false);
1876 
1877  // Add a fake function body to the block. IR generation is responsible
1878  // for filling in the actual body, which cannot be expressed as an AST.
1879  Block->setBody(new (Context) CompoundStmt(ConvLocation));
1880 
1881  // Create the block literal expression.
1882  Expr *BuildBlock = new (Context) BlockExpr(Block, Conv->getConversionType());
1883  ExprCleanupObjects.push_back(Block);
1884  Cleanup.setExprNeedsCleanups(true);
1885 
1886  return BuildBlock;
1887 }
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:2669
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:4462
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:1779
QualType getConversionType() const
Returns the type that this conversion function is converting to.
Definition: DeclCXX.h:2714
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:812
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:16005
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:3215
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:1932
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:2847
< 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:3484
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 setLambdaMangling(unsigned ManglingNumber, Decl *ContextDecl)
Set the mangling number and context declaration for a lambda class.
Definition: DeclCXX.h:1721
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:7736
void addInitCapture(sema::LambdaScopeInfo *LSI, VarDecl *Var)
Add an init-capture to a lambda scope.
Definition: SemaLambda.cpp:840
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:608
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:1727
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:1963
const LangOptions & getLangOpts() const
Definition: Sema.h:1284
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:500
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:329
CompoundStmt - This represents a group of statements like { stmt stmt }.
Definition: Stmt.h:1310
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:479
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:436
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:2805
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:2266
void setInvalidDecl(bool Invalid=true)
setInvalidDecl - Indicates the Decl had a semantic error.
Definition: DeclBase.cpp:132
void setRetValue(Expr *E)
Definition: Stmt.h:2645
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:444
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:1144
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:2610
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:2677
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:2643
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
CXXMethodDecl * startLambdaDefinition(CXXRecordDecl *Class, SourceRange IntroducerRange, TypeSourceInfo *MethodType, SourceLocation EndLoc, ArrayRef< ParmVarDecl *> Params, ConstexprSpecKind ConstexprKind, Optional< std::pair< unsigned, Decl *>> Mangling=None)
Start the definition of a lambda expression.
Definition: SemaLambda.cpp:359
Represents a static or instance method of a struct/union/class.
Definition: DeclCXX.h:1892
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:536
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:2655
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:655
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:2015
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:2447
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:483
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:847
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:4638
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:4342
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:4019
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:3488
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
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:4473
A trivial tuple used to represent a source range.
void setLexicalDeclContext(DeclContext *DC)
Definition: DeclBase.cpp:299
ASTContext & Context
Definition: Sema.h:375
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:748
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:3922
unsigned getNumParams() const
Return the number of parameters this function must have based on its FunctionType.
Definition: Decl.cpp:3176
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:629
No in-class initializer.
Definition: Specifiers.h:259
Declaration of a template function.
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