vm_backtrace.c: RB_GC_GUARD

* include/ruby/ruby.h (RB_GC_GUARD_PTR): add note.
* vm_backtrace.c (backtrace_to_str_ary): use RB_GC_GUARD() instead of
  RB_GC_GUARD_PTR() which has no effect.
  (backtrace_to_location_ary): ditto.
  (vm_backtrace_to_ary): ditto.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@38015 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,12 @@
+Fri Nov 30 09:38:22 2012  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* include/ruby/ruby.h (RB_GC_GUARD_PTR): add note.
+
+	* vm_backtrace.c (backtrace_to_str_ary): use RB_GC_GUARD() instead of
+	  RB_GC_GUARD_PTR() which has no effect.
+	  (backtrace_to_location_ary): ditto.
+	  (vm_backtrace_to_ary): ditto.
+
 Fri Nov 30 09:22:52 2012  Eric Hodel  <drbrain@segment7.net>
 
 	* lib/rubygems/commands/contents_command.rb:  Sort output from command.

include/ruby/ruby.h

@@ -512,6 +512,8 @@ enum ruby_value_type {
 static inline int rb_type(VALUE obj);
 #define TYPE(x) rb_type((VALUE)(x))
 
+/* RB_GC_GUARD_PTR() is an intermediate macro, and has no effect by
+ * itself.  don't use it directly */
 #ifdef __GNUC__
 #define RB_GC_GUARD_PTR(ptr) \
     __extension__ ({volatile VALUE *rb_gc_guarded_ptr = (ptr); rb_gc_guarded_ptr;})

vm_backtrace.c

@@ -512,7 +512,7 @@ backtrace_to_str_ary(VALUE self, long lev, long n)
     }
 
     r = backtrace_collect(bt, lev, n, location_to_str_dmyarg, 0);
-    RB_GC_GUARD_PTR(&self);
+    RB_GC_GUARD(self);
     return r;
 }
 
@@ -559,7 +559,7 @@ backtrace_to_location_ary(VALUE self, long lev, long n)
     }
 
     r = backtrace_collect(bt, lev, n, location_create, (void *)self);
-    RB_GC_GUARD_PTR(&self);
+    RB_GC_GUARD(self);
     return r;
 }
 
@@ -770,7 +770,7 @@ vm_backtrace_to_ary(rb_thread_t *th, int argc, VALUE *argv, int lev_default, int
     else {
 	r = backtrace_to_location_ary(btval, lev, n);
     }
-    RB_GC_GUARD_PTR(&btval);
+    RB_GC_GUARD(btval);
     return r;
 }