2 files changed, 69 insertions, 7 deletions

diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp
index 66ec800c726..82e59ddafee 100644
--- a/clang/lib/Sema/SemaDeclCXX.cpp
+++ b/clang/lib/Sema/SemaDeclCXX.cpp
@@ -9051,21 +9051,52 @@ bool Sema::isImplicitlyDeleted(FunctionDecl *FD) {
          isa<CXXMethodDecl>(FD);
 }
 
+/// \brief Mark the call operator of the given lambda closure type as "used".
+static void markLambdaCallOperatorUsed(Sema &S, CXXRecordDecl *Lambda) {
+  CXXMethodDecl *CallOperator 
+  = cast<CXXMethodDecl>(
+      *Lambda->lookup(
+        S.Context.DeclarationNames.getCXXOperatorName(OO_Call)).first);
+  CallOperator->setReferenced();
+  CallOperator->setUsed();
+}
+
 void Sema::DefineImplicitLambdaToFunctionPointerConversion(
        SourceLocation CurrentLocation,
        CXXConversionDecl *Conv) 
 {
+  CXXRecordDecl *Lambda = Conv->getParent();
+  
+  // Make sure that the lambda call operator is marked used.
+  markLambdaCallOperatorUsed(*this, Lambda);
+  
   Conv->setUsed();
   
   ImplicitlyDefinedFunctionScope Scope(*this, Conv);
   DiagnosticErrorTrap Trap(Diags);
   
-  // Introduce a bogus body, which IR generation will override anyway.
-  Conv->setBody(new (Context) CompoundStmt(Context, 0, 0, Conv->getLocation(),
+  // Return the address of the __invoke function.
+  DeclarationName InvokeName = &Context.Idents.get("__invoke");
+  CXXMethodDecl *Invoke 
+    = cast<CXXMethodDecl>(*Lambda->lookup(InvokeName).first);
+  Expr *FunctionRef = BuildDeclRefExpr(Invoke, Invoke->getType(),
+                                       VK_LValue, Conv->getLocation()).take();
+  assert(FunctionRef && "Can't refer to __invoke function?");
+  Stmt *Return = ActOnReturnStmt(Conv->getLocation(), FunctionRef).take();
+  Conv->setBody(new (Context) CompoundStmt(Context, &Return, 1, 
+                                           Conv->getLocation(),
                                            Conv->getLocation()));
+    
+  // Fill in the __invoke function with a dummy implementation. IR generation
+  // will fill in the actual details.
+  Invoke->setUsed();
+  Invoke->setReferenced();
+  Invoke->setBody(new (Context) CompoundStmt(Context, 0, 0, Conv->getLocation(),
+                                             Conv->getLocation()));
   
   if (ASTMutationListener *L = getASTMutationListener()) {
     L->CompletedImplicitDefinition(Conv);
+    L->CompletedImplicitDefinition(Invoke);
   }
 }
 
@@ -9073,6 +9104,8 @@ void Sema::DefineImplicitLambdaToBlockPointerConversion(
        SourceLocation CurrentLocation,
        CXXConversionDecl *Conv) 
 {
+  // Make sure that the lambda call operator is marked used.
+  markLambdaCallOperatorUsed(*this, Conv->getParent());
   Conv->setUsed();
   
   ImplicitlyDefinedFunctionScope Scope(*this, Conv);
diff --git a/clang/lib/Sema/SemaLambda.cpp b/clang/lib/Sema/SemaLambda.cpp
index 4e5935701b3..2af946288f4 100644
--- a/clang/lib/Sema/SemaLambda.cpp
+++ b/clang/lib/Sema/SemaLambda.cpp
@@ -372,17 +372,18 @@ static void addFunctionPointerConversion(Sema &S,
                                          SourceRange IntroducerRange,
                                          CXXRecordDecl *Class,
                                          CXXMethodDecl *CallOperator) {
+  // Add the conversion to function pointer.
   const FunctionProtoType *Proto
     = CallOperator->getType()->getAs<FunctionProtoType>(); 
   QualType FunctionPtrTy;
+  QualType FunctionTy;
   {
     FunctionProtoType::ExtProtoInfo ExtInfo = Proto->getExtProtoInfo();
     ExtInfo.TypeQuals = 0;
-    QualType FunctionTy
-      = S.Context.getFunctionType(Proto->getResultType(),
-                                  Proto->arg_type_begin(),
-                                  Proto->getNumArgs(),
-                                  ExtInfo);
+    FunctionTy = S.Context.getFunctionType(Proto->getResultType(),
+                                           Proto->arg_type_begin(),
+                                           Proto->getNumArgs(),
+                                           ExtInfo);
     FunctionPtrTy = S.Context.getPointerType(FunctionTy);
   }
   
@@ -409,6 +410,34 @@ static void addFunctionPointerConversion(Sema &S,
   Conversion->setAccess(AS_public);
   Conversion->setImplicit(true);
   Class->addDecl(Conversion);
+  
+  // Add a non-static member function "__invoke" that will be the result of
+  // the conversion.
+  Name = &S.Context.Idents.get("__invoke");
+  CXXMethodDecl *Invoke
+    = CXXMethodDecl::Create(S.Context, Class, Loc, 
+                            DeclarationNameInfo(Name, Loc), FunctionTy, 
+                            CallOperator->getTypeSourceInfo(),
+                            /*IsStatic=*/true, SC_Static, /*IsInline=*/true,
+                            /*IsConstexpr=*/false, 
+                            CallOperator->getBody()->getLocEnd());
+  SmallVector<ParmVarDecl *, 4> InvokeParams;
+  for (unsigned I = 0, N = CallOperator->getNumParams(); I != N; ++I) {
+    ParmVarDecl *From = CallOperator->getParamDecl(I);
+    InvokeParams.push_back(ParmVarDecl::Create(S.Context, Invoke,
+                                               From->getLocStart(),
+                                               From->getLocation(),
+                                               From->getIdentifier(),
+                                               From->getType(),
+                                               From->getTypeSourceInfo(),
+                                               From->getStorageClass(),
+                                               From->getStorageClassAsWritten(),
+                                               /*DefaultArg=*/0));
+  }
+  Invoke->setParams(InvokeParams);
+  Invoke->setAccess(AS_private);
+  Invoke->setImplicit(true);
+  Class->addDecl(Invoke);
 }
 
 /// \brief Add a lambda's conversion to block pointer.