Major anonymous union/struct redesign.
A new AST node is introduced:
   def IndirectField : DDecl<Value>;
IndirectFields are injected into the anonymous's parent scope and chain back to
the original field. Name lookup for anonymous entities now result in an
IndirectFieldDecl instead of a FieldDecl.
There is no functionality change, the code generated should be the same.

llvm-svn: 119919
diff --git a/clang/lib/AST/Decl.cpp b/clang/lib/AST/Decl.cpp
index c448116..ef8f168 100644
--- a/clang/lib/AST/Decl.cpp
+++ b/clang/lib/AST/Decl.cpp
@@ -768,7 +768,7 @@
   if (isa<UsingShadowDecl>(D))
     D = cast<UsingShadowDecl>(D)->getTargetDecl();
 
-  if (isa<FieldDecl>(D))
+  if (isa<FieldDecl>(D) || isa<IndirectFieldDecl>(D))
     return true;
   if (isa<CXXMethodDecl>(D))
     return cast<CXXMethodDecl>(D)->isInstance();
@@ -2030,6 +2030,12 @@
   return new (C) EnumConstantDecl(CD, L, Id, T, E, V);
 }
 
+IndirectFieldDecl *IndirectFieldDecl::Create(ASTContext &C, DeclContext *DC,
+                                          SourceLocation L, IdentifierInfo *Id,
+                                          QualType T, NamedDecl **CH, int CHS) {
+  return new (C) IndirectFieldDecl(DC, L, Id, T, CH, CHS);
+}
+
 SourceRange EnumConstantDecl::getSourceRange() const {
   SourceLocation End = getLocation();
   if (Init)