Handle anonymous unions at the tree level.

        C++ ABI change: Mangle anonymous unions using the name of their
        first named field (by depth-first search).  Should not cause
        binary compatibility problems, though, as the compiler previously
        didn't emit anything for affected unions.
        * cp-tree.def (ALIAS_DECL): New tree code.
        * decl2.c (build_anon_union_vars): Build ALIAS_DECLs.  Return the
        first field, not the largest.
        (finish_anon_union): Don't mess with RTL.  Do set DECL_ASSEMBLER_NAME,
        push the decl, and write it out at namespace scope.
        * decl.c (lookup_name_real): See through an ALIAS_DECL.
        (pushdecl): Add namespace bindings for ALIAS_DECLs.
        * rtti.c (unemitted_tinfo_decl_p): Don't try to look at the name
        of a decl which doesn't have one.
        * typeck.c (build_class_member_access_expr): Don't recurse if
        we already have the type we want.


git-svn-id: https://gcc.gnu.org/svn/gcc/trunk@60314 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 4 insertions, 0 deletions

diff --git a/gcc/cp/cp-tree.def b/gcc/cp/cp-tree.def
index 1aae797a4c2..436f8406973 100644
--- a/gcc/cp/cp-tree.def
+++ b/gcc/cp/cp-tree.def
@@ -89,6 +89,10 @@ DEFTREECODE (THROW_EXPR, "throw_expr", 'e', 1)
    these to avoid actually creating instances of the empty classes.  */
 DEFTREECODE (EMPTY_CLASS_EXPR, "empty_class_expr", 'e', 0)
 
+/* A DECL which is really just a placeholder for an expression.  Used to
+   implement non-class scope anonymous unions.  */
+DEFTREECODE (ALIAS_DECL, "alias_decl", 'd', 0)
+
 /* A reference to a member function or member functions from a base
    class.  BASELINK_FUNCTIONS gives the FUNCTION_DECL,
    TEMPLATE_DECL, OVERLOAD, or TEMPLATE_ID_EXPR corresponding to the