From f4b88a45902af1802a1cb42ba48b1c474474f228 Mon Sep 17 00:00:00 2001
From: John McCall <rjmccall@apple.com>
Date: Sat, 10 Mar 2012 09:33:50 +0000
Subject: Remove BlockDeclRefExpr and introduce a bit on DeclRefExpr to track
 whether the referenced declaration comes from an enclosing local context. 
 I'm amenable to suggestions about the exact meaning of this bit.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@152491 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/CodeGen/CGExpr.cpp | 41 ++++++++++++++++++-----------------------
 1 file changed, 18 insertions(+), 23 deletions(-)

(limited to 'lib/CodeGen/CGExpr.cpp')

diff --git a/lib/CodeGen/CGExpr.cpp b/lib/CodeGen/CGExpr.cpp
index 3275327c9b..80233b5d28 100644
--- a/lib/CodeGen/CGExpr.cpp
+++ b/lib/CodeGen/CGExpr.cpp
@@ -679,9 +679,6 @@ LValue CodeGenFunction::EmitLValue(const Expr *E) {
            "Only single-element init list can be lvalue.");
     return EmitLValue(cast<InitListExpr>(E)->getInit(0));
 
-  case Expr::BlockDeclRefExprClass:
-    return EmitBlockDeclRefLValue(cast<BlockDeclRefExpr>(E));
-
   case Expr::CXXTemporaryObjectExprClass:
   case Expr::CXXConstructExprClass:
     return EmitCXXConstructLValue(cast<CXXConstructExpr>(E));
@@ -796,7 +793,9 @@ static ConstantEmissionKind checkVarTypeForConstantEmission(QualType type) {
 /// in a block or lambda, which means const int variables or constexpr
 /// literals or similar.
 CodeGenFunction::ConstantEmission
-CodeGenFunction::tryEmitAsConstant(ValueDecl *value, Expr *refExpr) {
+CodeGenFunction::tryEmitAsConstant(DeclRefExpr *refExpr) {
+  ValueDecl *value = refExpr->getDecl();
+
   // The value needs to be an enum constant or a constant variable.
   ConstantEmissionKind CEK;
   if (isa<ParmVarDecl>(value)) {
@@ -810,25 +809,19 @@ CodeGenFunction::tryEmitAsConstant(ValueDecl *value, Expr *refExpr) {
   }
   if (CEK == CEK_None) return ConstantEmission();
 
-  // We evaluate use an on-stack DeclRefExpr because the constant
-  // evaluator (quite reasonably) ignores BlockDeclRefExprs.
-  DeclRefExpr stackRef(value, refExpr->getType(), refExpr->getValueKind(),
-                       refExpr->getExprLoc());
-
-  // If it's okay to evaluate as a 
   Expr::EvalResult result;
   bool resultIsReference;
   QualType resultType;
 
   // It's best to evaluate all the way as an r-value if that's permitted.
   if (CEK != CEK_AsReferenceOnly &&
-      stackRef.EvaluateAsRValue(result, getContext())) {
+      refExpr->EvaluateAsRValue(result, getContext())) {
     resultIsReference = false;
     resultType = refExpr->getType();
 
   // Otherwise, try to evaluate as an l-value.
   } else if (CEK != CEK_AsValueOnly &&
-             stackRef.EvaluateAsLValue(result, getContext())) {
+             refExpr->EvaluateAsLValue(result, getContext())) {
     resultIsReference = true;
     resultType = value->getType();
 
@@ -848,10 +841,10 @@ CodeGenFunction::tryEmitAsConstant(ValueDecl *value, Expr *refExpr) {
   // This should probably fire even for 
   if (isa<VarDecl>(value)) {
     if (!getContext().DeclMustBeEmitted(cast<VarDecl>(value)))
-      EmitDeclRefExprDbgValue(&stackRef, C);
+      EmitDeclRefExprDbgValue(refExpr, C);
   } else {
     assert(isa<EnumConstantDecl>(value));
-    EmitDeclRefExprDbgValue(&stackRef, C);
+    EmitDeclRefExprDbgValue(refExpr, C);
   }
 
   // If we emitted a reference constant, we need to dereference that.
@@ -1499,27 +1492,34 @@ LValue CodeGenFunction::EmitDeclRefLValue(const DeclRefExpr *E) {
   }
 
   if (const VarDecl *VD = dyn_cast<VarDecl>(ND)) {
-    
     // Check if this is a global variable.
     if (VD->hasExternalStorage() || VD->isFileVarDecl()) 
       return EmitGlobalVarDeclLValue(*this, E, VD);
 
+    bool isBlockVariable = VD->hasAttr<BlocksAttr>();
+
     bool NonGCable = VD->hasLocalStorage() &&
                      !VD->getType()->isReferenceType() &&
-                     !VD->hasAttr<BlocksAttr>();
+                     !isBlockVariable;
 
     llvm::Value *V = LocalDeclMap[VD];
     if (!V && VD->isStaticLocal()) 
       V = CGM.getStaticLocalDeclAddress(VD);
 
     // Use special handling for lambdas.
-    if (!V)
+    if (!V) {
       if (FieldDecl *FD = LambdaCaptureFields.lookup(VD))
         return EmitLValueForField(CXXABIThisValue, FD, 0);
 
+      assert(isa<BlockDecl>(CurCodeDecl) && E->refersToEnclosingLocal());
+      CharUnits alignment = getContext().getDeclAlign(VD);
+      return MakeAddrLValue(GetAddrOfBlockDecl(VD, isBlockVariable),
+                            E->getType(), alignment);
+    }
+
     assert(V && "DeclRefExpr not entered in LocalDeclMap?");
 
-    if (VD->hasAttr<BlocksAttr>())
+    if (isBlockVariable)
       V = BuildBlockByrefAddress(V, VD);
 
     LValue LV;
@@ -1546,11 +1546,6 @@ LValue CodeGenFunction::EmitDeclRefLValue(const DeclRefExpr *E) {
   llvm_unreachable("Unhandled DeclRefExpr");
 }
 
-LValue CodeGenFunction::EmitBlockDeclRefLValue(const BlockDeclRefExpr *E) {
-  CharUnits Alignment = getContext().getDeclAlign(E->getDecl());
-  return MakeAddrLValue(GetAddrOfBlockDecl(E), E->getType(), Alignment);
-}
-
 LValue CodeGenFunction::EmitUnaryOpLValue(const UnaryOperator *E) {
   // __extension__ doesn't affect lvalue-ness.
   if (E->getOpcode() == UO_Extension)
-- 
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