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/Analysis/CFG.cpp b/lib/Analysis/CFG.cpp
index 1adb8b8..096c7a0 100644
--- a/lib/Analysis/CFG.cpp
+++ b/lib/Analysis/CFG.cpp
@@ -1085,11 +1085,16 @@
       return VisitExprWithCleanups(cast<ExprWithCleanups>(S), asc);
 
     case Stmt::CXXDefaultArgExprClass:
+    case Stmt::CXXDefaultInitExprClass:
       // FIXME: The expression inside a CXXDefaultArgExpr is owned by the
       // called function's declaration, not by the caller. If we simply add
       // this expression to the CFG, we could end up with the same Expr
       // appearing multiple times.
       // PR13385 / <rdar://problem/12156507>
+      //
+      // It's likewise possible for multiple CXXDefaultInitExprs for the same
+      // expression to be used in the same function (through aggregate
+      // initialization).
       return VisitStmt(S, asc);
 
     case Stmt::CXXBindTemporaryExprClass: