Various interrelated cleanups for lambdas:

  - Complete the lambda class when we finish the lambda expression
    (previously, it was left in the "being completed" state)
  - Actually return the LambdaExpr object and bind to the resulting
  temporary when needed.
  - Detect when cleanups are needed while capturing a variable into a
  lambda (e.g., due to default arguments in the copy constructor), and
  make sure those cleanups apply for the whole of the lambda
  expression.
    

llvm-svn: 150123

3 files changed, 41 insertions, 11 deletions

diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index 378930a0e5b..69731e45eff 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -4185,7 +4185,10 @@ void AnalyzeImplicitConversions(Sema &S, Expr *OrigE, SourceLocation CC) {
   BinaryOperator *BO = dyn_cast<BinaryOperator>(E);
   bool IsLogicalOperator = BO && BO->isLogicalOp();
   for (Stmt::child_range I = E->children(); I; ++I) {
-    Expr *ChildExpr = cast<Expr>(*I);
+    Expr *ChildExpr = dyn_cast<Expr>(*I);
+    if (!ChildExpr)
+      continue;
+
     if (IsLogicalOperator &&
         isa<StringLiteral>(ChildExpr->IgnoreParenImpCasts()))
       // Ignore checking string literals that are in logical operators.
diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index accf85171ee..aed6eaf4e3e 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -9652,7 +9652,8 @@ void Sema::TryCaptureVar(VarDecl *var, SourceLocation loc,
     Expr *copyExpr = 0;
     const RecordType *rtype;
     if (isLambda) {
-      CXXRecordDecl *Lambda = cast<LambdaScopeInfo>(CSI)->Lambda;
+      LambdaScopeInfo *LSI = cast<LambdaScopeInfo>(CSI);
+      CXXRecordDecl *Lambda = LSI->Lambda;
       QualType FieldType;
       if (byRef) {
         // C++11 [expr.prim.lambda]p15:
@@ -9704,6 +9705,11 @@ void Sema::TryCaptureVar(VarDecl *var, SourceLocation loc,
       //
       // FIXME: Introduce an initialization entity for lambda captures.
       // FIXME: Totally broken for arrays.
+      
+      // Introduce a new evaluation context for the initialization, so that
+      // temporaries introduced as part of the capture
+      PushExpressionEvaluationContext(PotentiallyEvaluated);
+
       Expr *Ref = new (Context) DeclRefExpr(var, type.getNonReferenceType(),
                                             VK_LValue, loc);
       InitializedEntity InitEntity
@@ -9717,6 +9723,17 @@ void Sema::TryCaptureVar(VarDecl *var, SourceLocation loc,
         if (!Result.isInvalid())
           copyExpr = Result.take();
       }
+
+      // If this initialization requires any cleanups (e.g., due to a
+      // default argument to a copy constructor), note that for the
+      // lambda.
+      if (ExprNeedsCleanups)
+        LSI->ExprNeedsCleanups = true;
+
+      // Exit the expression evaluation context used for the capture.
+      CleanupVarDeclMarking();
+      DiscardCleanupsInEvaluationContext();
+      PopExpressionEvaluationContext();
     } else if (!byRef && getLangOptions().CPlusPlus &&
         (rtype = type.getNonReferenceType()->getAs<RecordType>())) {
       // The capture logic needs the destructor, so make sure we mark it.
diff --git a/clang/lib/Sema/SemaLambda.cpp b/clang/lib/Sema/SemaLambda.cpp
index 3e9e2102448..b90f5e3d639 100644
--- a/clang/lib/Sema/SemaLambda.cpp
+++ b/clang/lib/Sema/SemaLambda.cpp
@@ -103,13 +103,11 @@ void Sema::ActOnStartOfLambdaDefinition(LambdaIntroducer &Intro,
   Method->setAccess(AS_public);
   Class->addDecl(Method);
   Method->setLexicalDeclContext(DC); // FIXME: Minor hack.
-  
+
+  // Attributes on the lambda apply to the method.  
   ProcessDeclAttributes(CurScope, Method, ParamInfo);
   
-  // Enter a new evaluation context to insulate the block from any
-  // cleanups from the enclosing full-expression.
-  PushExpressionEvaluationContext(PotentiallyEvaluated);
-  
+  // Introduce the function call operator as the current declaration context.
   PushDeclContext(CurScope, Method);
     
   // Introduce the lambda scope.
@@ -255,6 +253,9 @@ void Sema::ActOnStartOfLambdaDefinition(LambdaIntroducer &Intro,
 
   // FIXME: Check return type is complete, !isObjCObjectType
   
+  // Enter a new evaluation context to insulate the block from any
+  // cleanups from the enclosing full-expression.
+  PushExpressionEvaluationContext(PotentiallyEvaluated);  
 }
 
 void Sema::ActOnLambdaError(SourceLocation StartLoc, Scope *CurScope) {
@@ -273,8 +274,6 @@ ExprResult Sema::ActOnLambdaExpr(SourceLocation StartLoc,
   DiscardCleanupsInEvaluationContext();
   PopExpressionEvaluationContext();
 
-  // FIXME: End-of-lambda checking
-
   // Collect information from the lambda scope.
   llvm::SmallVector<LambdaExpr::Capture, 4> Captures;
   llvm::SmallVector<Expr *, 4> CaptureInits;
@@ -282,11 +281,13 @@ ExprResult Sema::ActOnLambdaExpr(SourceLocation StartLoc,
   CXXRecordDecl *Class;
   SourceRange IntroducerRange;
   bool ExplicitParams;
+  bool LambdaExprNeedsCleanups;
   {
     LambdaScopeInfo *LSI = getCurLambda();
     Class = LSI->Lambda;
     IntroducerRange = LSI->IntroducerRange;
     ExplicitParams = LSI->ExplicitParams;
+    LambdaExprNeedsCleanups = LSI->ExprNeedsCleanups;
 
     // Translate captures.
     for (unsigned I = 0, N = LSI->Captures.size(); I != N; ++I) {
@@ -331,16 +332,25 @@ ExprResult Sema::ActOnLambdaExpr(SourceLocation StartLoc,
       break;
     }
 
+    // Finalize the lambda class.
+    SmallVector<Decl*, 4> Fields(Class->field_begin(), Class->field_end());
+    ActOnFields(0, Class->getLocation(), Class, Fields, 
+                SourceLocation(), SourceLocation(), 0);
+    CheckCompletedCXXClass(Class);
+
     // C++ [expr.prim.lambda]p7:
     //   The lambda-expression's compound-statement yields the
     //   function-body (8.4) of the function call operator [...].
     ActOnFinishFunctionBody(LSI->CallOperator, Body, /*IsInstantation=*/false);
   }
 
+  if (LambdaExprNeedsCleanups)
+    ExprNeedsCleanups = true;
+
   Expr *Lambda = LambdaExpr::Create(Context, Class, IntroducerRange, 
                                     CaptureDefault, Captures, ExplicitParams, 
                                     CaptureInits, Body->getLocEnd());
-  (void)Lambda;
   Diag(StartLoc, diag::err_lambda_unsupported);
-  return ExprError();
+
+  return MaybeBindToTemporary(Lambda);
 }