2019-11-30  Jan Hubicka  <hubicka@ucw.cz>

	* cgraph.h (symtab_node): Add symver flag.
	* cgraphunit.c (process_symver_attribute): New.
	(process_common_attributes): Use process_symver_attribute.
	* lto-cgraph.c (lto_output_node): Stream symver.
	(lto_output_varpool_node): Stream symver.
	(input_overwrite_node): Stream symver.
	(input_varpool_node): Stream symver.
	* output.h (do_assemble_symver): Decalre.
	* symtab.c (symtab_node::dump_base): Dump symver.
	(symtab_node::verify_base): Verify symver.
	(symtab_node::resolve_alias): Handle symver.
	* varasm.c (do_assemble_symver): New function.
	* varpool.c (varpool_node::assemble_aliases): Use it.
	* doc/extend.texi: (symver attribute): Document.
	* config/elfos.h (ASM_OUTPUT_SYMVER_DIRECTIVE): New.

c-family/ChangeLog:

2019-11-30  Jan Hubicka  <hubicka@ucw.cz>

	* c-attribs.c (handle_symver_attribute): New function
	(c_common_attributes): Add symver.

From-SVN: r278878