Revert r193223 and r193216.

They were causing CodeGenCXX/mangle-exprs.cpp to fail.

Revert "Remove the circular reference to LambdaExpr in CXXRecordDecl."

Revert "Again: Teach TreeTransform and family how to transform generic lambdas nested within templates and themselves."

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@193226 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/TreeTransform.h b/lib/Sema/TreeTransform.h
index 2d22e4c..97e12d7 100644
--- a/lib/Sema/TreeTransform.h
+++ b/lib/Sema/TreeTransform.h
@@ -593,11 +593,6 @@
   /// \brief Transform the captures and body of a lambda expression.
   ExprResult TransformLambdaScope(LambdaExpr *E, CXXMethodDecl *CallOperator);
 
-  TemplateParameterList *TransformTemplateParameterList(
-        TemplateParameterList *TPL) {
-    return TPL;
-  }
-
   ExprResult TransformAddressOfOperand(Expr *E);
   ExprResult TransformDependentScopeDeclRefExpr(DependentScopeDeclRefExpr *E,
                                                 bool IsAddressOfOperand);
@@ -8272,102 +8267,48 @@
 ExprResult
 TreeTransform<Derived>::TransformLambdaExpr(LambdaExpr *E) {
  
-  getSema().PushLambdaScope();
-  LambdaScopeInfo *LSI = getSema().getCurLambda();
-  // Transform the template parameters, and add them to the current
-  // instantiation scope. The null case is handled correctly.
-  LSI->GLTemplateParameterList = getDerived().TransformTemplateParameterList(
-      E->getTemplateParameterList());
-
-  // Check to see if the TypeSourceInfo of the call operator needs to
-  // be transformed, and if so do the transformation in the 
-  // CurrentInstantiationScope.
-
-  TypeSourceInfo *OldCallOpTSI = E->getCallOperator()->getTypeSourceInfo();
-  FunctionProtoTypeLoc OldCallOpFPTL = 
-      OldCallOpTSI->getTypeLoc().getAs<FunctionProtoTypeLoc>();
-  TypeSourceInfo *NewCallOpTSI = 0;
-  
-  const bool CallOpWasAlreadyTransformed = 
-      getDerived().AlreadyTransformed(OldCallOpTSI->getType()); 
-  
-  // Use the Old Call Operator's TypeSourceInfo if it is already transformed.
-  if (CallOpWasAlreadyTransformed)  
-    NewCallOpTSI = OldCallOpTSI;  
-  else {
-    // Transform the TypeSourceInfo of the Original Lambda's Call Operator.
-    // The transformation MUST be done in the CurrentInstantiationScope since
-    // it introduces a mapping of the original to the newly created 
-    // transformed parameters.
-
-    TypeLocBuilder NewCallOpTLBuilder;
-    QualType NewCallOpType = TransformFunctionProtoType(NewCallOpTLBuilder, 
-                                                        OldCallOpFPTL, 
-                                                        0, 0);
-    NewCallOpTSI = NewCallOpTLBuilder.getTypeSourceInfo(getSema().Context,
-                                                        NewCallOpType);
+  // FIXME: Implement nested generic lambda transformations.
+  if (E->isGenericLambda()) {
+    getSema().Diag(E->getIntroducerRange().getBegin(), 
+      diag::err_glambda_not_fully_implemented) 
+      << " template transformation of generic lambdas not implemented yet";
+    return ExprError();
   }
-  // Extract the ParmVarDecls from the NewCallOpTSI and add them to
-  // the vector below - this will be used to synthesize the 
-  // NewCallOperator.  Additionally, add the parameters of the untransformed 
-  // lambda call operator to the CurrentInstantiationScope.
-  SmallVector<ParmVarDecl *, 4> Params;  
-  {
-    FunctionProtoTypeLoc NewCallOpFPTL = 
-        NewCallOpTSI->getTypeLoc().castAs<FunctionProtoTypeLoc>();
-    ParmVarDecl **NewParamDeclArray = NewCallOpFPTL.getParmArray();
-    const unsigned NewNumArgs = NewCallOpFPTL.getNumArgs();
-
-    for (unsigned I = 0; I < NewNumArgs; ++I) {
-      // If this call operator's type does not require transformation, 
-      // the parameters do not get added to the current instantiation scope, 
-      // - so ADD them! This allows the following to compile when the enclosing
-      // template is specialized and the entire lambda expression has to be
-      // transformed. 
-      // template<class T> void foo(T t) {
-      //   auto L = [](auto a) {
-      //       auto M = [](char b) { <-- note: non-generic lambda
-      //         auto N = [](auto c) {
-      //            int x = sizeof(a);
-      //            x = sizeof(b); <-- specifically this line
-      //            x = sizeof(c);
-      //          };
-      //        };
-      //      };
-      //    }
-      // foo('a')
-      if (CallOpWasAlreadyTransformed)
-        getDerived().transformedLocalDecl(NewParamDeclArray[I],
-                                          NewParamDeclArray[I]);
-      // Add to Params array, so these parameters can be used to create
-      // the newly transformed call operator.
-      Params.push_back(NewParamDeclArray[I]);
-    }
-  }
-
-  if (!NewCallOpTSI)
+  // Transform the type of the lambda parameters and start the definition of
+  // the lambda itself.
+  TypeSourceInfo *MethodTy
+    = TransformType(E->getCallOperator()->getTypeSourceInfo());
+  if (!MethodTy)
     return ExprError();
 
   // Create the local class that will describe the lambda.
   CXXRecordDecl *Class
     = getSema().createLambdaClosureType(E->getIntroducerRange(),
-                                        NewCallOpTSI,
-                                        /*KnownDependent=*/false,
-                                        E->getCaptureDefault());
-
+                                        MethodTy,
+                                        /*KnownDependent=*/false);
   getDerived().transformedLocalDecl(E->getLambdaClass(), Class);
 
+  // Transform lambda parameters.
+  SmallVector<QualType, 4> ParamTypes;
+  SmallVector<ParmVarDecl *, 4> Params;
+  if (getDerived().TransformFunctionTypeParams(E->getLocStart(),
+        E->getCallOperator()->param_begin(),
+        E->getCallOperator()->param_size(),
+        0, ParamTypes, &Params))
+    return ExprError();
+  getSema().PushLambdaScope();
+  LambdaScopeInfo *LSI = getSema().getCurLambda();
+  // TODO: Fix for nested lambdas
+  LSI->GLTemplateParameterList = 0;
   // Build the call operator.
-  CXXMethodDecl *NewCallOperator
+  CXXMethodDecl *CallOperator
     = getSema().startLambdaDefinition(Class, E->getIntroducerRange(),
-                                      NewCallOpTSI,
+                                      MethodTy,
                                       E->getCallOperator()->getLocEnd(),
                                       Params);
-  LSI->CallOperator = NewCallOperator;
+  getDerived().transformAttrs(E->getCallOperator(), CallOperator);
 
-  getDerived().transformAttrs(E->getCallOperator(), NewCallOperator);
-
-  return getDerived().TransformLambdaScope(E, NewCallOperator);
+  return getDerived().TransformLambdaScope(E, CallOperator);
 }
 
 template<typename Derived>