C++1y: Allow aggregates to have default initializers.

Add a CXXDefaultInitExpr, analogous to CXXDefaultArgExpr, and use it both in
CXXCtorInitializers and in InitListExprs to represent a default initializer.

There's an additional complication here: because the default initializer can
refer to the initialized object via its 'this' pointer, we need to make sure
that 'this' points to the right thing within the evaluation.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@179958 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Serialization/ASTReaderStmt.cpp b/lib/Serialization/ASTReaderStmt.cpp
index b18114f..c7748b7 100644
--- a/lib/Serialization/ASTReaderStmt.cpp
+++ b/lib/Serialization/ASTReaderStmt.cpp
@@ -1230,6 +1230,12 @@
   E->Loc = ReadSourceLocation(Record, Idx);
 }
 
+void ASTStmtReader::VisitCXXDefaultInitExpr(CXXDefaultInitExpr *E) {
+  VisitExpr(E);
+  E->Field = ReadDeclAs<FieldDecl>(Record, Idx);
+  E->Loc = ReadSourceLocation(Record, Idx);
+}
+
 void ASTStmtReader::VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E) {
   VisitExpr(E);
   E->setTemporary(Reader.ReadCXXTemporary(F, Record, Idx));
@@ -2111,6 +2117,9 @@
         S = new (Context) CXXDefaultArgExpr(Empty);
       break;
     }
+    case EXPR_CXX_DEFAULT_INIT:
+      S = new (Context) CXXDefaultInitExpr(Empty);
+      break;
     case EXPR_CXX_BIND_TEMPORARY:
       S = new (Context) CXXBindTemporaryExpr(Empty);
       break;
diff --git a/lib/Serialization/ASTWriterStmt.cpp b/lib/Serialization/ASTWriterStmt.cpp
index 61ddec0..5c8e213 100644
--- a/lib/Serialization/ASTWriterStmt.cpp
+++ b/lib/Serialization/ASTWriterStmt.cpp
@@ -1223,6 +1223,13 @@
   Code = serialization::EXPR_CXX_DEFAULT_ARG;
 }
 
+void ASTStmtWriter::VisitCXXDefaultInitExpr(CXXDefaultInitExpr *E) {
+  VisitExpr(E);
+  Writer.AddDeclRef(E->getField(), Record);
+  Writer.AddSourceLocation(E->getExprLoc(), Record);
+  Code = serialization::EXPR_CXX_DEFAULT_INIT;
+}
+
 void ASTStmtWriter::VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E) {
   VisitExpr(E);
   Writer.AddCXXTemporary(E->getTemporary(), Record);