version.c: show +JIT when --jit is passed

in version output.
version.h: ditto
ruby.c: propagate option for it
common.mk: updated dependency for version.c

mjit.c: overwrites the RUBY_DESCRIPTION to have +JIT when --jit is passed

test/ruby/test_rubyoptions.rb: add test for them

Only `ruby --jit -v` will have "+JIT", but this is intentional.
This may not be convenient for debugging by ticket with `ruby -v`,
but it's convenient for benchmark tools that pass options (--jit)
when showing it. At least such behavior is planned for benchmark_driver.gem
and this behavior is designed for it. Other benchmark tools are
recommended to follow the behavior too if they show version.
RUBY_DESCRIPTION might be useful for it too.

The position of "+JIT" is changed from original proposal because other
platforms like JRuby and TruffleRuby end it with archtecture.
It's made similar to JRuby, but it's upper-cased because Matz made approval
for "+JIT" in the ticket.

Example:
$ ruby -v
ruby 2.6.0dev (2018-02-22 trunk 62529) [x86_64-linux]
$ ruby --jit -v
ruby 2.6.0dev (2018-02-22 trunk 62529) +JIT [x86_64-linux]

After --jit is made default in the future, this output may be removed.
So do not rely on this output if possible.

[Feature #14462]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@62530 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 5 insertions, 2 deletions

diff --git a/ruby.c b/ruby.c
index 46451bf727..081b0a154f 100644
--- a/ruby.c
+++ b/ruby.c
@@ -1506,6 +1506,10 @@ process_options(int argc, char **argv, ruby_cmdline_options_t *opt)
     const struct rb_block *base_block;
     unsigned int dump = opt->dump & dump_exit_bits;
 
+#ifndef MJIT_FORCE_ENABLE /* to use with: ./configure cppflags="-DMJIT_FORCE_ENABLE" */
+    opt->mjit.on = 1;
+#endif
+
     if (opt->dump & (DUMP_BIT(usage)|DUMP_BIT(help))) {
 	const char *const progname =
 	    (argc > 0 && argv && argv[0] ? argv[0] :
@@ -1538,6 +1542,7 @@ process_options(int argc, char **argv, ruby_cmdline_options_t *opt)
 	rb_warning("-K is specified; it is for 1.8 compatibility and may cause odd behavior");
 
     if (opt->dump & (DUMP_BIT(version) | DUMP_BIT(version_v))) {
+        mjit_opts.on = opt->mjit.on; /* used by ruby_show_version(). mjit_init() is still not called here. */
 	ruby_show_version();
 	if (opt->dump & DUMP_BIT(version)) return Qtrue;
     }
@@ -1590,9 +1595,7 @@ process_options(int argc, char **argv, ruby_cmdline_options_t *opt)
     ruby_gc_set_params(opt->safe_level);
     ruby_init_loadpath_safe(opt->safe_level);
 
-#ifndef MJIT_FORCE_ENABLE /* to use with: ./configure cppflags="-DMJIT_FORCE_ENABLE" */
     if (opt->mjit.on)
-#endif
         /* Using TMP_RUBY_PREFIX created by ruby_init_loadpath_safe(). */
         mjit_init(&opt->mjit);