Index: libitm/alloc_cpp.cc
===================================================================
--- libitm/alloc_cpp.cc (revision 183968)
+++ libitm/alloc_cpp.cc (working copy)
@@ -60,7 +60,7 @@ extern void _ZdlPvRKSt9nothrow_t (void *, c_nothro
 extern void *_ZnaXRKSt9nothrow_t (size_t, c_nothrow_p) __attribute__((weak));
 extern void _ZdaPvRKSt9nothrow_t (void *, c_nothrow_p) __attribute__((weak));
 
-#if !defined (HAVE_ELF_STYLE_WEAKREF)
+#if !defined (HAVE_ELF_STYLE_WEAKREF) && !defined (__MACH__)
 void *_ZnwX (size_t) { return NULL; }
 void _ZdlPv (void *) { return; }
 void *_ZnaX (size_t) { return NULL; }
Index: libitm/eh_cpp.cc
===================================================================
--- libitm/eh_cpp.cc    (revision 183968)
+++ libitm/eh_cpp.cc    (working copy)
@@ -39,7 +39,7 @@ extern void *__cxa_begin_catch (void *) WEAK;
 extern void *__cxa_end_catch (void) WEAK;
 extern void __cxa_tm_cleanup (void *, void *, unsigned int) WEAK;
 
-#if !defined (HAVE_ELF_STYLE_WEAKREF)
+#if !defined (HAVE_ELF_STYLE_WEAKREF) && !defined (__MACH__)
 void *__cxa_allocate_exception (size_t) { return NULL; }
 void __cxa_throw (void *, void *, void *) { return; }
 void *__cxa_begin_catch (void *) { return NULL; }
Index: libgcc/config/darwin-crt-tm.c
===================================================================
--- libgcc/config/darwin-crt-tm.c       (revision 183968)
+++ libgcc/config/darwin-crt-tm.c       (working copy)
@@ -23,33 +23,68 @@ a copy of the GCC Runtime Library Exception along
 see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 <http://www.gnu.org/licenses/>.  */
 
+#include "tsystem.h"
+#include <stddef.h>
+#include <dlfcn.h>
 #include <mach-o/dyld.h>
+#include <mach-o/getsect.h>
 
-/* not listed in mach-o/dyld.h for some reason.  */
-extern char * getsectdata (const char*,const char*,unsigned long*); 
+#ifdef __LP64__
+#define GET_DATA_TMCT(mh,size) \
+  getsectdatafromheader_64 ((struct mach_header_64*) mh, \
+                           "__DATA", "__tm_clone_table", (uint64_t *)size)
+#else
+#define GET_DATA_TMCT(mh,size) \
+  getsectdatafromheader (mh, "__DATA", "__tm_clone_table", (uint32_t *)size)
+#endif
 
 #define WEAK __attribute__((weak))
+#define UNUSED __attribute__((unused))
 
 extern void _ITM_registerTMCloneTable (void *, size_t) WEAK;
 extern void _ITM_deregisterTMCloneTable (void *) WEAK;
 
+#if defined(START) || defined(END)
+static inline void *getTMCloneTable (const void *f, size_t *tmct_siz)
+{
+  char *tmct_fixed, *tmct = NULL;
+  unsigned int i, img_count; 
+  struct mach_header *mh;
+  Dl_info info;
+  
+  if (! dladdr (f, &info) || info.dli_fbase == NULL)
+    abort ();
+  
+  mh = (struct mach_header *) info.dli_fbase;
+  tmct_fixed = GET_DATA_TMCT (mh, tmct_siz);
+  *tmct_siz /= (sizeof (size_t) * 2);
+  /* No tm_clone_table or no clones. */
+  if (tmct_fixed == NULL || *tmct_siz == 0)
+    return NULL; 
+
+  img_count = _dyld_image_count();
+  for (i = 0; i < img_count && tmct == NULL; i++)
+    {
+      if (mh == _dyld_get_image_header(i))
+       tmct = tmct_fixed + (unsigned long)_dyld_get_image_vmaddr_slide(i); 
+    }
+
+  return tmct;
+}
+#endif
+
 #ifdef START
 
 void __doTMRegistrations (void) __attribute__ ((constructor));
 
 void __doTMRegistrations (void)
 {
-  char * tm_clone_table_sect_data;
-  unsigned long tmct_siz;
-  
-  tm_clone_table_sect_data = getsectdata ("__DATA",
-                                         "__tm_clone_table",
-                                         &tmct_siz);
-  tmct_siz /= (sizeof (size_t) * 2);
-  if (_ITM_registerTMCloneTable != NULL
-      && tm_clone_table_sect_data != NULL
-      && tmct_siz > 0)
-    _ITM_registerTMCloneTable (tm_clone_table_sect_data, (size_t)tmct_siz);
+  size_t tmct_siz;
+  void *tmct;
+
+  tmct = getTMCloneTable ((const void *)&__doTMRegistrations, &tmct_siz);
+  if (_ITM_registerTMCloneTable != NULL && tmct != NULL)
+    _ITM_registerTMCloneTable (tmct, (size_t)tmct_siz);
 }
 
 #endif
@@ -60,18 +95,53 @@ void __doTMdeRegistrations (void) __attribute__ ((
 
 void __doTMdeRegistrations (void)
 {
-  char * tm_clone_table_sect_data;
-  unsigned long tmct_siz;
-  
-  tm_clone_table_sect_data = getsectdata ("__DATA",
-                                         "__tm_clone_table",
-                                         &tmct_siz);
-  
-  if (_ITM_deregisterTMCloneTable != NULL
-      && tm_clone_table_sect_data != NULL
-      && tmct_siz > 0)
-    _ITM_deregisterTMCloneTable (tm_clone_table_sect_data);
+  size_t tmct_siz;
+  void *tmct;
 
+  tmct = getTMCloneTable ((const void *)&__doTMdeRegistrations, &tmct_siz);
+  if (_ITM_deregisterTMCloneTable != NULL && tmct != NULL)
+    _ITM_deregisterTMCloneTable (tmct);
 }
 
+/* Provide dummy functions to satisfy linkage for versions of the Darwin tool-chain that
+   that can't handle undefined weak refs at the link stage.  */
+
+extern void *__cxa_allocate_exception (size_t) WEAK;
+extern void __cxa_throw (void *, void *, void *) WEAK;
+extern void *__cxa_begin_catch (void *) WEAK;
+extern void *__cxa_end_catch (void) WEAK;
+extern void __cxa_tm_cleanup (void *, void *, unsigned int) WEAK;
+
+void *__cxa_allocate_exception (size_t s UNUSED) { return NULL; }
+void __cxa_throw (void * a UNUSED, void * b UNUSED, void * c UNUSED)
+{ return; }
+void *__cxa_begin_catch (void * a UNUSED) { return NULL; }
+void *__cxa_end_catch (void) { return NULL; }
+void __cxa_tm_cleanup (void * a UNUSED, void * b UNUSED,  unsigned int c UNUSED)
+{ return; }
+
+extern void *_ZnwX (size_t) WEAK;
+extern void _ZdlPv (void *) WEAK;
+extern void *_ZnaX (size_t) WEAK;
+extern void _ZdaPv (void *) WEAK;
+
+typedef const struct nothrow_t { } *c_nothrow_p;
+
+extern void *_ZnwXRKSt9nothrow_t (size_t, c_nothrow_p) WEAK;
+extern void _ZdlPvRKSt9nothrow_t (void *, c_nothrow_p) WEAK;
+extern void *_ZnaXRKSt9nothrow_t (size_t, c_nothrow_p) WEAK;
+extern void _ZdaPvRKSt9nothrow_t (void *, c_nothrow_p) WEAK;
+
+void *_ZnwX (size_t s UNUSED) { return NULL; }
+void _ZdlPv (void * a UNUSED) { return; }
+void *_ZnaX (size_t s UNUSED) { return NULL; }
+void _ZdaPv (void * a UNUSED) { return; }
+
+void *_ZnwXRKSt9nothrow_t (size_t s UNUSED, c_nothrow_p b UNUSED)
+  { return NULL; }
+void _ZdlPvRKSt9nothrow_t (void * a UNUSED, c_nothrow_p b UNUSED)  { return; }
+void *_ZnaXRKSt9nothrow_t (size_t s UNUSED, c_nothrow_p b UNUSED)
+ { return NULL; }
+void _ZdaPvRKSt9nothrow_t (void * a UNUSED, c_nothrow_p b UNUSED) { return; }
+
 #endif
