From 16ee0252305fbd4f40ea39c3c4421dc7f103f8a0 Mon Sep 17 00:00:00 2001
From: Vladimir Kargov <vkargov@users.noreply.github.com>
Date: Thu, 12 Feb 2015 17:45:34 +0300
Subject: [PATCH] [runtime] Mark TLS variables as explicitly used to avoid
 their unwarranted deletion by the compiler overlooking their usage in inline
 assembly sections.

---
 mono/metadata/sgen-alloc.c | 2 +-
 mono/utils/mono-compiler.h | 8 +++++++-
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/mono/metadata/sgen-alloc.c b/mono/metadata/sgen-alloc.c
index 12beef8..aa475bc 100644
--- a/mono/metadata/sgen-alloc.c
+++ b/mono/metadata/sgen-alloc.c
@@ -93,7 +93,7 @@ static __thread char *tlab_next;
 static __thread char *tlab_temp_end;
 static __thread char *tlab_real_end;
 /* Used by the managed allocator/wbarrier */
-static __thread char **tlab_next_addr;
+static __thread char **tlab_next_addr MONO_ATTR_USED;
 #endif
 
 #ifdef HAVE_KW_THREAD
diff --git a/mono/utils/mono-compiler.h b/mono/utils/mono-compiler.h
index 6cb60f2..a910e91 100644
--- a/mono/utils/mono-compiler.h
+++ b/mono/utils/mono-compiler.h
@@ -7,13 +7,19 @@
  */
 #include <config.h>
 
+#ifdef __GNUC__
+#define MONO_ATTR_USED __attribute__ ((used))
+#else
+#define MONO_ATTR_USED
+#endif
+
 #ifdef HAVE_KW_THREAD
 
 #define MONO_HAVE_FAST_TLS
 #define MONO_FAST_TLS_SET(x,y) x = y
 #define MONO_FAST_TLS_GET(x) x
 #define MONO_FAST_TLS_INIT(x)
-#define MONO_FAST_TLS_DECLARE(x) static __thread gpointer x MONO_TLS_FAST;
+#define MONO_FAST_TLS_DECLARE(x) static __thread gpointer x MONO_TLS_FAST MONO_ATTR_USED;
 
 #if HAVE_TLS_MODEL_ATTR