Introduce a new expression node, ImplicitValueInitExpr, that

represents an implicit value-initialization of a subobject of a
particular type. This replaces the (ab)use of CXXZeroValueInitExpr
within initializer lists for the "holes" that occur due to the use of
C99 designated initializers.

The new test case is currently XFAIL'd, because CodeGen's
ConstExprEmitter (in lib/CodeGen/CGExprConstant.cpp) needs to be
taught to value-initialize when it sees ImplicitValueInitExprs.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@63317 91177308-0d34-0410-b5e6-96231b3b80d8

4 files changed, 12 insertions, 8 deletions

diff --git a/lib/CodeGen/CGExprAgg.cpp b/lib/CodeGen/CGExprAgg.cpp
index b487bacc71..f985763b5c 100644
--- a/lib/CodeGen/CGExprAgg.cpp
+++ b/lib/CodeGen/CGExprAgg.cpp
@@ -339,10 +339,10 @@ void AggExprEmitter::EmitNonConstInit(InitListExpr *E) {
 
 void AggExprEmitter::EmitInitializationToLValue(Expr* E, LValue LV) {
   // FIXME: Are initializers affected by volatile?
-  if (E->getType()->isComplexType()) {
-    CGF.EmitComplexExprIntoAddr(E, LV.getAddress(), false);
-  } else if (isa<CXXZeroInitValueExpr>(E)) {
+  if (isa<ImplicitValueInitExpr>(E)) {
     EmitNullInitializationToLValue(LV, E->getType());
+  } else if (E->getType()->isComplexType()) {
+    CGF.EmitComplexExprIntoAddr(E, LV.getAddress(), false);
   } else if (CGF.hasAggregateLLVMType(E->getType())) {
     CGF.EmitAnyExpr(E, LV.getAddress(), false);
   } else {
diff --git a/lib/CodeGen/CGExprComplex.cpp b/lib/CodeGen/CGExprComplex.cpp
index 73fceedee5..387635cb06 100644
--- a/lib/CodeGen/CGExprComplex.cpp
+++ b/lib/CodeGen/CGExprComplex.cpp
@@ -130,6 +130,12 @@ public:
     llvm::Constant *Null = llvm::Constant::getNullValue(CGF.ConvertType(Elem));
     return ComplexPairTy(Null, Null);
   }
+  ComplexPairTy VisitImplicitValueInitExpr(ImplicitValueInitExpr *E) {
+    assert(E->getType()->isAnyComplexType() && "Expected complex type!");
+    QualType Elem = E->getType()->getAsComplexType()->getElementType();
+    llvm::Constant *Null = llvm::Constant::getNullValue(CGF.ConvertType(Elem));
+    return ComplexPairTy(Null, Null);
+  }
   
   struct BinOpInfo {
     ComplexPairTy LHS;
diff --git a/lib/CodeGen/CGExprConstant.cpp b/lib/CodeGen/CGExprConstant.cpp
index e523ab3acf..3aedf9bc7f 100644
--- a/lib/CodeGen/CGExprConstant.cpp
+++ b/lib/CodeGen/CGExprConstant.cpp
@@ -248,11 +248,6 @@ public:
 
     FieldDecl* curField = ILE->getInitializedFieldInUnion();
     if (!curField) {
-#ifndef NDEBUG
-#endif
-    }
-
-    if (!curField) {
       // There's no field to initialize, so value-initialize the union.
 #ifndef NDEBUG
       // Make sure that it's really an empty and not a failure of
diff --git a/lib/CodeGen/CGExprScalar.cpp b/lib/CodeGen/CGExprScalar.cpp
index dd8b30041e..f855e23ba0 100644
--- a/lib/CodeGen/CGExprScalar.cpp
+++ b/lib/CodeGen/CGExprScalar.cpp
@@ -200,6 +200,9 @@ public:
     return V;
   }
   
+  Value *VisitImplicitValueInitExpr(const ImplicitValueInitExpr *E) {
+    return llvm::Constant::getNullValue(ConvertType(E->getType()));
+  }
   Value *VisitImplicitCastExpr(const ImplicitCastExpr *E);
   Value *VisitCastExpr(const CastExpr *E) { 
     return EmitCastExpr(E->getSubExpr(), E->getType());