Come up with TARGET_GET_VALID_OPTION_VALUES option hook (PR driver/83193).

Come up with TARGET_GET_VALID_OPTION_VALUES option hook (PR driver/83193).

2018-09-03  Martin Liska  <mliska@suse.cz>

        PR driver/83193
	* common/common-target.def: Add TARGET_GET_VALID_OPTION_VALUES.
	* common/common-targhooks.c (default_get_valid_option_values):
        New function.
	* common/common-targhooks.h (default_get_valid_option_values):
        Likewise.
	* common/config/i386/i386-common.c: Move processor_target_table
        from i386.c.
	(ix86_get_valid_option_values): New function.
	(TARGET_GET_VALID_OPTION_VALUES): New macro.
	* config/i386/i386.c (struct ptt): Move to i386-common.c.
	(PTA_*): Move all defined masks into i386-common.c.
	(ix86_function_specific_restore): Use new processor_cost_table.
	* config/i386/i386.h (struct ptt): Moved from i386.c.
	(struct pta): Likewise.
	* doc/tm.texi: Document new TARGET_GET_VALID_OPTION_VALUES.
	* doc/tm.texi.in: Likewise.
	* opt-suggestions.c (option_proposer::suggest_option):
        Pass prefix to build_option_suggestions.
	(option_proposer::get_completions): Likewise.
	(option_proposer::build_option_suggestions): Use the new target
        hook.
	* opts.c (struct option_help_tuple): New struct.
	(print_filtered_help): Use the new target hook.
2018-09-03  Martin Liska  <mliska@suse.cz>

        PR driver/83193
	* gcc.dg/completion-4.c: New test.

From-SVN: r264052