2010-06-28  Bingfeng Mei <bmei@broadcom.com>

        * cgraph.h (struct varpool_node): new used_from_object_file flag.
        (struct cgraph_local_info): new used_from_object_file flag.
        * cgraph.c (dump_cgraph_node): dump used_from_object_file flag.
        (cgraph_clone_node): initialize used_from_object_file.
        (cgraph_create_virtual_clone): initialize used_from_object_file.
        * lto-symbtab.c (lto_symtab_merge_decls_1): Set
        used_from_object_file flags for symbols of LDPR_PREVAILING_DEF
        when compiling with -fwhole-program.
        (lto_symtab_resolve_symbols) Use LDPR_PREVAILING_DEF_IRONLY for
	internal resolver.
        * ipa.c (function_and_variable_visibility): Set externally_visible
        flag of varpool_node if used_from_object_file flag is set.
        (cgraph_externally_visible_p): check used_from_object_file flag.
        * doc/invoke.texi (-fwhole-program option): Change description of
        externally_visible attribute accordingly.
        * doc/extend.texi (externally_visible): Ditto.

From-SVN: r161483