From 1b5d3c0b9d8a984157160c860661a7723a4a5a7f Mon Sep 17 00:00:00 2001
From: Eric Wong <e@80x24.org>
Date: Tue, 18 Feb 2014 07:31:52 +0000
Subject: gc.c: try to make GC guard stronger for non-GCC/MSC

---
 gc.c                | 8 ++++++--
 include/ruby/ruby.h | 8 ++++++--
 2 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/gc.c b/gc.c
index fc85cd4cee..7f9e54f08a 100644
--- a/gc.c
+++ b/gc.c
@@ -88,10 +88,14 @@
 #define rb_setjmp(env) RUBY_SETJMP(env)
 #define rb_jmp_buf rb_jmpbuf_t
 
-#if defined(HAVE_RB_GC_GUARDED_PTR) && HAVE_RB_GC_GUARDED_PTR
+#if defined(HAVE_RB_GC_GUARDED_PTR_VAL) && HAVE_RB_GC_GUARDED_PTR_VAL
+/* trick the compiler into thinking a external signal handler uses this */
+volatile VALUE rb_gc_guarded_val;
 volatile VALUE *
-rb_gc_guarded_ptr(volatile VALUE *ptr)
+rb_gc_guarded_ptr_val(volatile VALUE *ptr, VALUE val)
 {
+    rb_gc_guarded_val = val;
+
     return ptr;
 }
 #endif
diff --git a/include/ruby/ruby.h b/include/ruby/ruby.h
index 55ea252d98..abd4b4bad3 100644
--- a/include/ruby/ruby.h
+++ b/include/ruby/ruby.h
@@ -515,12 +515,16 @@ static inline int rb_type(VALUE obj);
 static inline volatile VALUE *rb_gc_guarded_ptr(volatile VALUE *ptr) {return ptr;}
 #pragma optimize("", on)
 #else
-volatile VALUE *rb_gc_guarded_ptr(volatile VALUE *ptr);
-#define HAVE_RB_GC_GUARDED_PTR 1
+volatile VALUE *rb_gc_guarded_ptr_val(volatile VALUE *ptr, VALUE val);
+#define HAVE_RB_GC_GUARDED_PTR_VAL 1
+#define RB_GC_GUARD(v) (*rb_gc_guarded_ptr_val(&(v),(v)))
 #endif
 #define RB_GC_GUARD_PTR(ptr) rb_gc_guarded_ptr(ptr)
 #endif
+
+#ifndef RB_GC_GUARD
 #define RB_GC_GUARD(v) (*RB_GC_GUARD_PTR(&(v)))
+#endif
 
 #ifdef __GNUC__
 #define RB_UNUSED_VAR(x) x __attribute__ ((unused))
-- 
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