Add "-fsave-optimization-record"

Add "-fsave-optimization-record"

This patch implements a -fsave-optimization-record option, which
leads to a JSON file being written out, recording the dump_* calls
made (via the optinfo infrastructure).

The patch includes a minimal version of the JSON patch I posted last
year, with just enough support needed for optimization records (I
removed all of the parser code, leaving just the code for building
in-memory JSON trees and writing them to a pretty_printer).

gcc/ChangeLog:
	* Makefile.in (OBJS): Add json.o and optinfo-emit-json.o.
	(CFLAGS-optinfo-emit-json.o): Define TARGET_NAME.
	* common.opt (fsave-optimization-record): New option.
	* coretypes.h (struct kv_pair): Move here from dumpfile.c.
	* doc/invoke.texi (-fsave-optimization-record): New option.
	* dumpfile.c: Include "optinfo-emit-json.h".
	(struct kv_pair): Move to coretypes.h.
	(optgroup_options): Make non-static.
	(dump_context::end_scope): Call
	optimization_records_maybe_pop_dump_scope.
	* dumpfile.h (optgroup_options): New decl.
	* json.cc: New file.
	* json.h: New file.
	* optinfo-emit-json.cc: New file.
	* optinfo-emit-json.h: New file.
	* optinfo.cc: Include "optinfo-emit-json.h".
	(optinfo::emit): Call optimization_records_maybe_record_optinfo.
	(optinfo_enabled_p): Check optimization_records_enabled_p.
	(optinfo_wants_inlining_info_p): Likewise.
	* optinfo.h: Update comment.
	* profile-count.c (profile_quality_as_string): New function.
	* profile-count.h (profile_quality_as_string): New decl.
	(profile_count::quality): New accessor.
	* selftest-run-tests.c (selftest::run_tests): Call json_cc_tests
	and optinfo_emit_json_cc_tests.
	* selftest.h (selftest::json_cc_tests): New decl.
	(selftest::optinfo_emit_json_cc_tests): New decl.
	* toplev.c: Include "optinfo-emit-json.h".
	(compile_file): Call optimization_records_finish.
	(do_compile): Call optimization_records_start.
	* tree-ssa-live.c: Include optinfo.h.
	(remove_unused_scope_block_p): Retain inlining information if
	optinfo_wants_inlining_info_p returns true.

From-SVN: r262905