k0kubun	2018-03-13 21:29:55 +0900 (Tue, 13 Mar 2018)

  New Revision: 62741

  https://svn.ruby-lang.org/cgi-bin/viewvc.cgi?view=revision&revision=62741

  Log:
    mjit_compile.c: disable comment_id by default
    
    Doing `rb_ary_aref` to `global_symbols.ids` is not thread-safe and
    randomly causes SEGV.
    https://gist.github.com/k0kubun/ab60727c6be7c0e777d2b4241f59173c
    
    But it's convenient for development. So I keep it optionally available.

  Modified files:
    trunk/mjit_compile.c
Index: mjit_compile.c
===================================================================
--- mjit_compile.c	(revision 62740)
+++ mjit_compile.c	(revision 62741)
@@ -78,9 +78,13 @@ compile_case_dispatch_each(VALUE key, VA https://github.com/ruby/ruby/blob/trunk/mjit_compile.c#L78
     return ST_CONTINUE;
 }
 
+#define MJIT_COMMENT_ID 0
+
+/* Calling rb_id2str in MJIT worker causes random SEGV. So this is disabled by default. */
 static void
 comment_id(FILE *f, ID id)
 {
+#ifdef MJIT_COMMENT_ID
     VALUE name = rb_id2str(id);
     const char *p, *e;
     char c, prev = '\0';
@@ -98,6 +102,7 @@ comment_id(FILE *f, ID id) https://github.com/ruby/ruby/blob/trunk/mjit_compile.c#L102
 	prev = c;
     }
     fputs("\" */", f);
+#endif
 }
 
 static void compile_insns(FILE *f, const struct rb_iseq_constant_body *body, unsigned int stack_size,

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