mame	2017-10-25 22:19:45 +0900 (Wed, 25 Oct 2017)

  New Revision: 60427

  https://svn.ruby-lang.org/cgi-bin/viewvc.cgi?view=revision&revision=60427

  Log:
    Make imemo_alloc writebarrier-unprotected
    
    imemo_alloc provides a memory buffer whose contents are marked by GC.
    C code can access imemo_alloc buffer freely, so imemo_alloc must be
    considered writebarrier-unprotected.  But T_IMEMO is writebarrier-
    protected by default, which caused a GC bug.

  Modified files:
    trunk/gc.c
    trunk/parse.y
Index: parse.y
===================================================================
--- parse.y	(revision 60426)
+++ parse.y	(revision 60427)
@@ -11538,6 +11538,7 @@ rb_parser_malloc(struct parser_params *p https://github.com/ruby/ruby/blob/trunk/parse.y#L11538
     size_t cnt = HEAPCNT(1, size);
     rb_imemo_alloc_t *n = NEWHEAP();
     void *ptr = xmalloc(size);
+    rb_gc_writebarrier_unprotect((VALUE)n);
 
     return ADD2HEAP(n, cnt, ptr);
 }
@@ -11548,6 +11549,7 @@ rb_parser_calloc(struct parser_params *p https://github.com/ruby/ruby/blob/trunk/parse.y#L11549
     size_t cnt = HEAPCNT(nelem, size);
     rb_imemo_alloc_t *n = NEWHEAP();
     void *ptr = xcalloc(nelem, size);
+    rb_gc_writebarrier_unprotect((VALUE)n);
 
     return ADD2HEAP(n, cnt, ptr);
 }
@@ -11569,6 +11571,7 @@ rb_parser_realloc(struct parser_params * https://github.com/ruby/ruby/blob/trunk/parse.y#L11571
     }
     n = NEWHEAP();
     ptr = xrealloc(ptr, size);
+    rb_gc_writebarrier_unprotect((VALUE)n);
     return ADD2HEAP(n, cnt, ptr);
 }
 
Index: gc.c
===================================================================
--- gc.c	(revision 60426)
+++ gc.c	(revision 60427)
@@ -8118,6 +8118,7 @@ rb_alloc_tmp_buffer_with_count(volatile https://github.com/ruby/ruby/blob/trunk/gc.c#L8118
     void *ptr;
 
     s = rb_imemo_new(imemo_alloc, 0, 0, 0, 0);
+    rb_gc_writebarrier_unprotect(s);
     ptr = ruby_xmalloc0(size);
     a = (rb_imemo_alloc_t*)s;
     a->ptr = (VALUE*)ptr;

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