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

1 files changed, 12 insertions, 1 deletions

diff --git a/lib/AST/Expr.cpp b/lib/AST/Expr.cpp
index c1c8084cd5..8a04198293 100644
--- a/lib/AST/Expr.cpp
+++ b/lib/AST/Expr.cpp
@@ -735,6 +735,8 @@ bool Expr::isConstantInitializer(ASTContext &Ctx) const {
     }
     return true;
   }
+  case ImplicitValueInitExprClass:
+    return true;
   case ParenExprClass: {
     return cast<ParenExpr>(this)->getSubExpr()->isConstantInitializer(Ctx);
   }
@@ -1672,7 +1674,7 @@ Stmt::child_iterator InitListExpr::child_end() {
   return InitExprs.size() ? &InitExprs[0] + InitExprs.size() : 0;
 }
 
-/// DesignatedInitExpr
+// DesignatedInitExpr
 Stmt::child_iterator DesignatedInitExpr::child_begin() {
   char* Ptr = static_cast<char*>(static_cast<void *>(this));
   Ptr += sizeof(DesignatedInitExpr);
@@ -1683,6 +1685,15 @@ Stmt::child_iterator DesignatedInitExpr::child_end() {
   return child_iterator(&*child_begin() + NumSubExprs);
 }
 
+// ImplicitValueInitExpr
+Stmt::child_iterator ImplicitValueInitExpr::child_begin() { 
+  return child_iterator(); 
+}
+
+Stmt::child_iterator ImplicitValueInitExpr::child_end() { 
+  return child_iterator(); 
+}
+
 // ObjCStringLiteral
 Stmt::child_iterator ObjCStringLiteral::child_begin() { 
   return child_iterator();