fix win thread size calc.

[mono.git] / mono / utils / mach-support-amd64.c

diff --git a/mono/utils/mach-support-amd64.c b/mono/utils/mach-support-amd64.c
index e889a522c496690f3d89fc9dd8932775085deb4d..19040885da612aaf9908a3dedec6831aab1b491e 100644 (file)
--- a/mono/utils/mach-support-amd64.c
+++ b/mono/utils/mach-support-amd64.c
@@ -3,8 +3,10 @@
  *
  * Authors:
  *   Geoff Norton (gnorton@novell.com)
+ *   Rodrigo Kumpera (kumpera@gmail.com)
  *
  * (C) 2010 Novell, Inc.
+ * (C) 2013 Xamarin, Inc.
  */
 
 #include <config.h>
@@ -16,6 +18,14 @@
 #include "utils/mono-sigcontext.h"
 #include "mach-support.h"
 
+/* Known offsets used for TLS storage*/
+
+/* All OSX versions up to 10.8 */
+#define TLS_VECTOR_OFFSET_CATS 0x60
+#define TLS_VECTOR_OFFSET_10_9 0xe0
+
+static int tls_vector_offset;
+
 void *
 mono_mach_arch_get_ip (thread_state_t state)
 {
@@ -85,11 +95,11 @@ void *
 mono_mach_get_tls_address_from_thread (pthread_t thread, pthread_key_t key)
 {
        /* OSX stores TLS values in a hidden array inside the pthread_t structure
-        * They are keyed off a giant array offset 0x60 into the pointer.  This value
+        * They are keyed off a giant array from a known offset into the pointer.  This value
         * is baked into their pthread_getspecific implementation
         */
        intptr_t *p = (intptr_t *)thread;
-       intptr_t **tsd = (intptr_t **) ((char*)p + 0x60);
+       intptr_t **tsd = (intptr_t **) ((char*)p + tls_vector_offset);
 
        return (void *) &tsd [key];
 }
@@ -100,4 +110,29 @@ mono_mach_arch_get_tls_value_from_thread (pthread_t thread, guint32 key)
        return *(void**)mono_mach_get_tls_address_from_thread (thread, key);
 }
 
+void
+mono_mach_init (pthread_key_t key)
+{
+       void *old_value = pthread_getspecific (key);
+       void *canary = (void*)0xDEADBEEFu;
+
+       pthread_key_create (&key, NULL);
+       g_assert (old_value != canary);
+
+       pthread_setspecific (key, canary);
+
+       /*First we probe for cats*/
+       tls_vector_offset = TLS_VECTOR_OFFSET_CATS;
+       if (mono_mach_arch_get_tls_value_from_thread (pthread_self (), key) == canary)
+               goto ok;
+
+       tls_vector_offset = TLS_VECTOR_OFFSET_10_9;
+       if (mono_mach_arch_get_tls_value_from_thread (pthread_self (), key) == canary)
+               goto ok;
+
+       g_error ("could not discover the mach TLS offset");
+ok:
+       pthread_setspecific (key, old_value);
+}
+
 #endif