gcc:

	* config/darwin-crt2.c: Move to ../libgcc/config/rs6000.
	* config/darwin-crt3.c: Move to ../libgcc/config.
	* config/t-darwin (EXTRA_MULTILIB_PARTS): Remove.
	($(T)crt3$(objext)): Remove.
	* config/rs6000/t-darwin (DARWIN_EXTRA_CRT_BUILD_CFLAGS): Remove.
	($(T)crt2$(objext)): Remove.
	* config.gcc (powerpc-*-darwin*): Remove extra_parts.
	(powerpc64-*-darwin*): Likewise.

	gcc/po:
	* EXCLUDES (config/darwin-crt2.c): Remove.

	libgcc:
	* config/darwin-crt3.o: New file.
	* config/rs6000/darwin-crt2.c: New file.
	* config/t-darwin: New file.
	* config/rs6000/t-darwin (DARWIN_EXTRA_CRT_BUILD_CFLAGS): New variable.
	(crt2.o): New rule.
	* config.host (*-*-darwin*): Add crt3.o to extra_parts.
	(powerpc-*-darwin*): Add crt2.o to extra_parts.
	(powerpc64-*-darwin*): Likewise.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@176239 138bc75d-0d04-0410-961f-82ee72b054a4

6 files changed, 708 insertions, 0 deletions

diff --git a/libgcc/ChangeLog b/libgcc/ChangeLog
index c358ae4126a..bfbf1053157 100644
--- a/libgcc/ChangeLog
+++ b/libgcc/ChangeLog
@@ -1,5 +1,16 @@
 2011-07-13  Rainer Orth  <ro@CeBiTec.Uni-Bielefeld.DE>
 
+	* config/darwin-crt3.o: New file.
+	* config/rs6000/darwin-crt2.c: New file.
+	* config/t-darwin: New file.
+	* config/rs6000/t-darwin (DARWIN_EXTRA_CRT_BUILD_CFLAGS): New variable.
+	(crt2.o): New rule.
+	* config.host (*-*-darwin*): Add crt3.o to extra_parts.
+	(powerpc-*-darwin*): Add crt2.o to extra_parts.
+	(powerpc64-*-darwin*): Likewise.
+
+2011-07-13  Rainer Orth  <ro@CeBiTec.Uni-Bielefeld.DE>
+
 	* config/i386/netware-crt0.c: New file.
 	* config/i386/t-nwld: Rename to ...
 	* config/i386/t-slibgcc-nwld: ... this.
diff --git a/libgcc/config.host b/libgcc/config.host
index 6b6caffde95..56ce998a62b 100644
--- a/libgcc/config.host
+++ b/libgcc/config.host
@@ -153,6 +153,7 @@ case ${host} in
 *-*-darwin*)
   asm_hidden_op=.private_extern
   tmake_file="t-darwin ${cpu_type}/t-darwin t-slibgcc-darwin"
+  extra_parts=crt3.o
   ;;
 *-*-freebsd[12] | *-*-freebsd[12].* | *-*-freebsd*aout*)
   # This is the place-holder for the generic a.out configuration
@@ -528,8 +529,10 @@ powerpc-*-darwin*)
 	  md_unwind_header=rs6000/darwin-unwind.h
 	  ;;
 	esac
+	extra_parts="$extra_parts crt2.o"
 	;;
 powerpc64-*-darwin*)
+	extra_parts="$extra_parts crt2.o"
 	;;
 powerpc-*-freebsd*)
 	tmake_file="${tmake_file} rs6000/t-ppccomm rs6000/t-freebsd t-softfp"
diff --git a/libgcc/config/darwin-crt3.c b/libgcc/config/darwin-crt3.c
new file mode 100644
index 00000000000..9b64f2aa8c3
--- /dev/null
+++ b/libgcc/config/darwin-crt3.c
@@ -0,0 +1,532 @@
+/* __cxa_atexit backwards-compatibility support for Darwin.
+   Copyright (C) 2006, 2009 Free Software Foundation, Inc.
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 3, or (at your option) any later
+version.
+
+GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+Under Section 7 of GPL version 3, you are granted additional
+permissions described in the GCC Runtime Library Exception, version
+3.1, as published by the Free Software Foundation.
+
+You should have received a copy of the GNU General Public License and
+a copy of the GCC Runtime Library Exception along with this program;
+see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+<http://www.gnu.org/licenses/>.  */
+
+/* Don't do anything if we are compiling for a kext multilib. */
+#ifdef __PIC__
+
+/* It is incorrect to include config.h here, because this file is being
+   compiled for the target, and hence definitions concerning only the host
+   do not apply.  */
+
+#include "tconfig.h"
+#include "tsystem.h"
+
+#include <dlfcn.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <string.h>
+
+/* This file works around two different problems.
+
+   The first problem is that there is no __cxa_atexit on Mac OS versions
+   before 10.4.  It fixes this by providing a complete atexit and
+   __cxa_atexit emulation called from the regular atexit.
+
+   The second problem is that on all shipping versions of Mac OS,
+   __cxa_finalize and exit() don't work right: they don't run routines
+   that were registered while other atexit routines are running.  This
+   is worked around by wrapping each atexit/__cxa_atexit routine with
+   our own routine which ensures that any __cxa_atexit calls while it
+   is running are honoured.
+
+   There are still problems which this does not solve.  Before 10.4,
+   shared objects linked with previous compilers won't have their
+   atexit calls properly interleaved with code compiled with newer
+   compilers.  Also, atexit routines registered from shared objects
+   linked with previous compilers won't get the bug fix.  */
+
+typedef int (*cxa_atexit_p)(void (*func) (void*), void* arg, const void* dso);
+typedef void (*cxa_finalize_p)(const void *dso);
+typedef int (*atexit_p)(void (*func)(void));
+
+/* These are from "keymgr.h".  */
+extern void *_keymgr_get_and_lock_processwide_ptr (unsigned key);
+extern int _keymgr_get_and_lock_processwide_ptr_2 (unsigned, void **);
+extern int _keymgr_set_and_unlock_processwide_ptr (unsigned key, void *ptr);
+
+extern void *__keymgr_global[];
+typedef struct _Sinfo_Node {
+        unsigned int size ;             /*size of this node*/
+        unsigned short major_version ;  /*API major version.*/
+        unsigned short minor_version ;  /*API minor version.*/
+        } _Tinfo_Node ;
+
+#ifdef __ppc__
+#define CHECK_KEYMGR_ERROR(e) \
+  (((_Tinfo_Node *)__keymgr_global[2])->major_version >= 4 ? (e) : 0)
+#else
+#define CHECK_KEYMGR_ERROR(e) (e)
+#endif
+
+/* Our globals are stored under this keymgr index.  */
+#define KEYMGR_ATEXIT_LIST	14
+
+/* The different kinds of callback routines.  */
+typedef void (*atexit_callback)(void);
+typedef void (*cxa_atexit_callback)(void *);
+
+/* This structure holds a routine to call.  There may be extra fields
+   at the end of the structure that this code doesn't know about.  */
+struct one_atexit_routine 
+{
+  union {
+    atexit_callback ac;
+    cxa_atexit_callback cac;
+  } callback;
+  /* has_arg is 0/2/4 if 'ac' is live, 1/3/5 if 'cac' is live.  
+     Higher numbers indicate a later version of the structure that this
+     code doesn't understand and will ignore.  */
+  int has_arg;
+  void * arg;
+};
+
+struct atexit_routine_list
+{
+  struct atexit_routine_list * next;
+  struct one_atexit_routine r;
+};
+
+/* The various possibilities for status of atexit().  */
+enum atexit_status {
+  atexit_status_unknown = 0,
+  atexit_status_missing = 1,
+  atexit_status_broken = 2,
+  atexit_status_working = 16
+};
+
+struct keymgr_atexit_list
+{
+  /* Version of this list.  This code knows only about version 0.
+     If the version is higher than 0, this code may add new atexit routines
+     but should not attempt to run the list.  */
+  short version;
+  /* 1 if an atexit routine is currently being run by this code, 0
+     otherwise.  */
+  char running_routines;
+  /* Holds a value from 'enum atexit_status'.  */
+  unsigned char atexit_status;
+  /* The list of atexit and cxa_atexit routines registered.  If
+   atexit_status_missing it contains all routines registered while
+   linked with this code.  If atexit_status_broken it contains all
+   routines registered during cxa_finalize while linked with this
+   code.  */
+  struct atexit_routine_list *l;
+  /* &__cxa_atexit; set if atexit_status >= atexit_status_broken.  */
+  cxa_atexit_p cxa_atexit_f;
+  /* &__cxa_finalize; set if atexit_status >= atexit_status_broken.  */
+  cxa_finalize_p cxa_finalize_f;
+  /* &atexit; set if atexit_status >= atexit_status_working
+     or atexit_status == atexit_status_missing.  */
+  atexit_p atexit_f;
+};
+
+/* Return 0 if __cxa_atexit has the bug it has in Mac OS 10.4: it
+   fails to call routines registered while an atexit routine is
+   running.  Return 1 if it works properly, and -1 if an error occurred.  */
+
+struct atexit_data 
+{
+  int result;
+  cxa_atexit_p cxa_atexit;
+};
+
+static void cxa_atexit_check_2 (void *arg)
+{
+  ((struct atexit_data *)arg)->result = 1;
+}
+
+static void cxa_atexit_check_1 (void *arg)
+{
+  struct atexit_data * aed = arg;
+  if (aed->cxa_atexit (cxa_atexit_check_2, arg, arg) != 0)
+    aed->result = -1;
+}
+
+static int
+check_cxa_atexit (cxa_atexit_p cxa_atexit, cxa_finalize_p cxa_finalize)
+{
+  struct atexit_data aed = { 0, cxa_atexit };
+
+  /* We re-use &aed as the 'dso' parameter, since it's a unique address.  */
+  if (cxa_atexit (cxa_atexit_check_1, &aed, &aed) != 0)
+    return -1;
+  cxa_finalize (&aed);
+  if (aed.result == 0)
+    {
+      /* Call __cxa_finalize again to make sure that cxa_atexit_check_2
+	 is removed from the list before AED goes out of scope.  */
+      cxa_finalize (&aed);
+      aed.result = 0;
+    }
+  return aed.result;
+}
+
+#ifdef __ppc__
+/* This comes from Csu.  It works only before 10.4.  The prototype has
+   been altered a bit to avoid casting.  */
+extern int _dyld_func_lookup(const char *dyld_func_name,
+     void *address) __attribute__((visibility("hidden")));
+
+static void our_atexit (void);
+
+/* We're running on 10.3.9.  Find the address of the system atexit()
+   function.  So easy to say, so hard to do.  */
+static atexit_p
+find_atexit_10_3 (void)
+{
+  unsigned int (*dyld_image_count_fn)(void);
+  const char *(*dyld_get_image_name_fn)(unsigned int image_index);
+  const void *(*dyld_get_image_header_fn)(unsigned int image_index);
+  const void *(*NSLookupSymbolInImage_fn)(const void *image, 
+					  const char *symbolName,
+					  unsigned int options);
+  void *(*NSAddressOfSymbol_fn)(const void *symbol);
+  unsigned i, count;
+  
+  /* Find some dyld functions.  */
+  _dyld_func_lookup("__dyld_image_count", &dyld_image_count_fn);
+  _dyld_func_lookup("__dyld_get_image_name", &dyld_get_image_name_fn);
+  _dyld_func_lookup("__dyld_get_image_header", &dyld_get_image_header_fn);
+  _dyld_func_lookup("__dyld_NSLookupSymbolInImage", &NSLookupSymbolInImage_fn);
+  _dyld_func_lookup("__dyld_NSAddressOfSymbol", &NSAddressOfSymbol_fn);
+
+  /* If any of these don't exist, that's an error.  */
+  if (! dyld_image_count_fn || ! dyld_get_image_name_fn
+      || ! dyld_get_image_header_fn || ! NSLookupSymbolInImage_fn
+      || ! NSAddressOfSymbol_fn)
+    return NULL;
+  
+  count = dyld_image_count_fn ();
+  for (i = 0; i < count; i++)
+    {
+      const char * path = dyld_get_image_name_fn (i);
+      const void * image;
+      const void * symbol;
+      
+      if (strcmp (path, "/usr/lib/libSystem.B.dylib") != 0)
+	continue;
+      image = dyld_get_image_header_fn (i);
+      if (! image)
+	return NULL;
+      /* '4' is NSLOOKUPSYMBOLINIMAGE_OPTION_RETURN_ON_ERROR.  */
+      symbol = NSLookupSymbolInImage_fn (image, "_atexit", 4);
+      if (! symbol)
+	return NULL;
+      return NSAddressOfSymbol_fn (symbol);
+    }
+  return NULL;
+}
+#endif
+
+/* Create (if necessary), find, lock, fill in, and return our globals.  
+   Return NULL on error, in which case the globals will not be locked.  
+   The caller should call keymgr_set_and_unlock.  */
+static struct keymgr_atexit_list *
+get_globals (void)
+{
+  struct keymgr_atexit_list * r;
+  
+#ifdef __ppc__
+  /* 10.3.9 doesn't have _keymgr_get_and_lock_processwide_ptr_2 so the
+     PPC side can't use it.  On 10.4 this just means the error gets
+     reported a little later when
+     _keymgr_set_and_unlock_processwide_ptr finds that the key was
+     never locked.  */
+  r = _keymgr_get_and_lock_processwide_ptr (KEYMGR_ATEXIT_LIST);
+#else
+  void * rr;
+  if (_keymgr_get_and_lock_processwide_ptr_2 (KEYMGR_ATEXIT_LIST, &rr))
+    return NULL;
+  r = rr;
+#endif
+  
+  if (r == NULL)
+    {
+      r = calloc (sizeof (struct keymgr_atexit_list), 1);
+      if (! r)
+	return NULL;
+    }
+
+  if (r->atexit_status == atexit_status_unknown)
+    {
+      void *handle;
+
+      handle = dlopen ("/usr/lib/libSystem.B.dylib", RTLD_NOLOAD);
+      if (!handle)
+	{
+#ifdef __ppc__
+	  r->atexit_status = atexit_status_missing;
+	  r->atexit_f = find_atexit_10_3 ();
+	  if (! r->atexit_f)
+	    goto error;
+	  if (r->atexit_f (our_atexit))
+	    goto error;
+#else
+	  goto error;
+#endif
+	}
+      else
+	{
+	  int chk_result;
+
+	  r->cxa_atexit_f = (cxa_atexit_p)dlsym (handle, "__cxa_atexit");
+	  r->cxa_finalize_f = (cxa_finalize_p)dlsym (handle, "__cxa_finalize");
+	  if (! r->cxa_atexit_f || ! r->cxa_finalize_f)
+	    goto error;
+
+	  chk_result = check_cxa_atexit (r->cxa_atexit_f, r->cxa_finalize_f);
+	  if (chk_result == -1)
+	    goto error;
+	  else if (chk_result == 0)
+	    r->atexit_status = atexit_status_broken;
+	  else
+	    {
+	      r->atexit_f = (atexit_p)dlsym (handle, "atexit");
+	      if (! r->atexit_f)
+		goto error;
+	      r->atexit_status = atexit_status_working;
+	    }
+	}
+    }
+
+  return r;
+  
+ error:
+  _keymgr_set_and_unlock_processwide_ptr (KEYMGR_ATEXIT_LIST, r);
+  return NULL;
+}
+
+/* Add TO_ADD to ATEXIT_LIST.  ATEXIT_LIST may be NULL but is
+   always the result of calling _keymgr_get_and_lock_processwide_ptr and
+   so KEYMGR_ATEXIT_LIST is known to be locked; this routine is responsible
+   for unlocking it.  */
+
+static int
+add_routine (struct keymgr_atexit_list * g,
+	     const struct one_atexit_routine * to_add)
+{
+  struct atexit_routine_list * s
+    = malloc (sizeof (struct atexit_routine_list));
+  int result;
+  
+  if (!s)
+    {
+      _keymgr_set_and_unlock_processwide_ptr (KEYMGR_ATEXIT_LIST, g);
+      return -1;
+    }
+  s->r = *to_add;
+  s->next = g->l;
+  g->l = s;
+  result = _keymgr_set_and_unlock_processwide_ptr (KEYMGR_ATEXIT_LIST, g);
+  return CHECK_KEYMGR_ERROR (result) == 0 ? 0 : -1;
+}
+
+/* This runs the routines in G->L up to STOP.  */
+static struct keymgr_atexit_list *
+run_routines (struct keymgr_atexit_list *g,
+	      struct atexit_routine_list *stop)
+{
+  for (;;)
+    {
+      struct atexit_routine_list * cur = g->l;
+      if (! cur || cur == stop)
+	break;
+      g->l = cur->next;
+      _keymgr_set_and_unlock_processwide_ptr (KEYMGR_ATEXIT_LIST, g);
+
+      switch (cur->r.has_arg) {
+      case 0: case 2: case 4:
+	cur->r.callback.ac ();
+	break;
+      case 1: case 3: case 5:
+	cur->r.callback.cac (cur->r.arg);
+	break;
+      default:
+	/* Don't understand, so don't call it.  */
+	break;
+      }
+      free (cur);
+
+      g = _keymgr_get_and_lock_processwide_ptr (KEYMGR_ATEXIT_LIST);
+      if (! g)
+	break;
+    }
+  return g;
+}
+
+/* Call the routine described by ROUTINE_PARAM and then call any
+   routines added to KEYMGR_ATEXIT_LIST while that routine was
+   running, all with in_cxa_finalize set.  */
+
+static void
+cxa_atexit_wrapper (void* routine_param)
+{
+  struct one_atexit_routine * routine = routine_param;
+  struct keymgr_atexit_list *g;
+  struct atexit_routine_list * base = NULL;
+  char prev_running = 0;
+  
+  g = _keymgr_get_and_lock_processwide_ptr (KEYMGR_ATEXIT_LIST);
+  if (g)
+    {
+      prev_running = g->running_routines;
+      g->running_routines = 1;
+      base = g->l;
+      _keymgr_set_and_unlock_processwide_ptr (KEYMGR_ATEXIT_LIST, g);
+    }
+
+  if (routine->has_arg)
+    routine->callback.cac (routine->arg);
+  else
+    routine->callback.ac ();
+
+  if (g)
+    g = _keymgr_get_and_lock_processwide_ptr (KEYMGR_ATEXIT_LIST);
+  if (g)
+    g = run_routines (g, base);
+  if (g)
+    {
+      g->running_routines = prev_running;
+      _keymgr_set_and_unlock_processwide_ptr (KEYMGR_ATEXIT_LIST, g);
+    }
+}
+
+#ifdef __ppc__
+/* This code is used while running on 10.3.9, when __cxa_atexit doesn't
+   exist in the system library.  10.3.9 only supported regular PowerPC,
+   so this code isn't necessary on x86 or ppc64.  */
+
+/* This routine is called from the system atexit(); it runs everything
+   registered on the KEYMGR_ATEXIT_LIST.  */
+
+static void
+our_atexit (void)
+{
+  struct keymgr_atexit_list *g;
+  char prev_running;
+
+  g = _keymgr_get_and_lock_processwide_ptr (KEYMGR_ATEXIT_LIST);
+  if (! g || g->version != 0 || g->atexit_status != atexit_status_missing)
+    return;
+  
+  prev_running = g->running_routines;
+  g->running_routines = 1;
+  g = run_routines (g, NULL);
+  if (! g)
+    return;
+  g->running_routines = prev_running;
+  _keymgr_set_and_unlock_processwide_ptr (KEYMGR_ATEXIT_LIST, g);
+}
+#endif
+
+/* This is our wrapper around atexit and __cxa_atexit.  It will return
+   nonzero if an error occurs, and otherwise:
+   - if in_cxa_finalize is set, or running on 10.3.9, add R to
+     KEYMGR_ATEXIT_LIST; or
+   - call the system __cxa_atexit to add cxa_atexit_wrapper with an argument
+     that indicates how cxa_atexit_wrapper should call R.  */
+
+static int
+atexit_common (const struct one_atexit_routine *r, const void *dso)
+{
+  struct keymgr_atexit_list *g = get_globals ();
+
+  if (! g)
+    return -1;
+  
+  if (g->running_routines || g->atexit_status == atexit_status_missing)
+    return add_routine (g, r);
+
+  if (g->atexit_status >= atexit_status_working)
+    {
+      int result;
+      if (r->has_arg)
+	{
+	  cxa_atexit_p cxa_atexit = g->cxa_atexit_f;
+	  result = _keymgr_set_and_unlock_processwide_ptr (KEYMGR_ATEXIT_LIST,
+							   g);
+	  if (CHECK_KEYMGR_ERROR (result))
+	    return -1;
+	  return cxa_atexit (r->callback.cac, r->arg, dso);
+	}
+      else
+	{
+	  atexit_p atexit_f = g->atexit_f;
+	  result = _keymgr_set_and_unlock_processwide_ptr (KEYMGR_ATEXIT_LIST,
+							   g);
+	  if (CHECK_KEYMGR_ERROR (result))
+	    return -1;
+	  return atexit_f (r->callback.ac);
+	}
+    }
+  else
+    {
+      cxa_atexit_p cxa_atexit = g->cxa_atexit_f;
+      struct one_atexit_routine *alloced;
+      int result;
+
+      result = _keymgr_set_and_unlock_processwide_ptr (KEYMGR_ATEXIT_LIST, g);
+      if (CHECK_KEYMGR_ERROR (result))
+	return -1;
+
+      alloced = malloc (sizeof (struct one_atexit_routine));
+      if (! alloced)
+	return -1;
+      *alloced = *r;
+      return cxa_atexit (cxa_atexit_wrapper, alloced, dso);
+    }
+}
+
+/* These are the actual replacement routines; they just funnel into
+   atexit_common.  */
+
+int __cxa_atexit (cxa_atexit_callback func, void* arg, 
+		  const void* dso) __attribute__((visibility("hidden")));
+
+int
+__cxa_atexit (cxa_atexit_callback func, void* arg, const void* dso)
+{
+  struct one_atexit_routine r;
+  r.callback.cac = func;
+  r.has_arg = 1;
+  r.arg = arg;
+  return atexit_common (&r, dso);
+}
+
+int atexit (atexit_callback func) __attribute__((visibility("hidden")));
+
+/* Use __dso_handle to allow even bundles that call atexit() to be unloaded
+   on 10.4.  */
+extern void __dso_handle;
+
+int
+atexit (atexit_callback func)
+{
+  struct one_atexit_routine r;
+  r.callback.ac = func;
+  r.has_arg = 0;
+  return atexit_common (&r, &__dso_handle);
+}
+
+#endif /* __PIC__ */
diff --git a/libgcc/config/rs6000/darwin-crt2.c b/libgcc/config/rs6000/darwin-crt2.c
new file mode 100644
index 00000000000..f4a584a8f9f
--- /dev/null
+++ b/libgcc/config/rs6000/darwin-crt2.c
@@ -0,0 +1,153 @@
+/* KeyMgr backwards-compatibility support for Darwin.
+   Copyright (C) 2001, 2002, 2004, 2009 Free Software Foundation, Inc.
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 3, or (at your option) any later
+version.
+
+GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+Under Section 7 of GPL version 3, you are granted additional
+permissions described in the GCC Runtime Library Exception, version
+3.1, as published by the Free Software Foundation.
+
+You should have received a copy of the GNU General Public License and
+a copy of the GCC Runtime Library Exception along with this program;
+see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+<http://www.gnu.org/licenses/>.  */
+
+/* It is incorrect to include config.h here, because this file is being
+   compiled for the target, and hence definitions concerning only the host
+   do not apply.  */
+
+#include "tconfig.h"
+#include "tsystem.h"
+
+/* This file doesn't do anything useful on non-powerpc targets, since they
+   don't have backwards compatibility anyway.  */
+
+#ifdef __ppc__
+
+/* Homemade decls substituting for getsect.h and dyld.h, so cross
+   compilation works.  */
+struct mach_header;
+extern char *getsectdatafromheader (struct mach_header *, const char *,
+				    const char *, unsigned long *);
+extern void _dyld_register_func_for_add_image
+  (void (*) (struct mach_header *, unsigned long));
+extern void _dyld_register_func_for_remove_image
+  (void (*) (struct mach_header *, unsigned long));
+
+extern void __darwin_gcc3_preregister_frame_info (void);
+
+/* These are from "keymgr.h".  */
+extern void _init_keymgr (void);
+extern void *_keymgr_get_and_lock_processwide_ptr (unsigned key);
+extern void _keymgr_set_and_unlock_processwide_ptr (unsigned key, void *ptr);
+
+extern void *__keymgr_global[];
+typedef struct _Sinfo_Node {
+        unsigned int size ;             /*size of this node*/
+        unsigned short major_version ;  /*API major version.*/
+        unsigned short minor_version ;  /*API minor version.*/
+        } _Tinfo_Node ;
+
+/* KeyMgr 3.x is the first one supporting GCC3 stuff natively.  */
+#define KEYMGR_API_MAJOR_GCC3           3       
+/* ... with these keys.  */
+#define KEYMGR_GCC3_LIVE_IMAGE_LIST	301     /* loaded images  */
+#define KEYMGR_GCC3_DW2_OBJ_LIST	302     /* Dwarf2 object list  */   
+
+/* Node of KEYMGR_GCC3_LIVE_IMAGE_LIST.  Info about each resident image.  */
+struct live_images {
+  unsigned long this_size;                      /* sizeof (live_images)  */
+  struct mach_header *mh;                       /* the image info  */
+  unsigned long vm_slide;
+  void (*destructor)(struct live_images *);     /* destructor for this  */
+  struct live_images *next;
+  unsigned int examined_p;
+  void *fde;
+  void *object_info;
+  unsigned long info[2];                        /* Future use.  */
+};
+
+
+/* These routines are used only on Darwin versions before 10.2.
+   Later versions have equivalent code in the system.  
+   Eventually, they might go away, although it might be a long time...  */
+
+static void darwin_unwind_dyld_remove_image_hook 
+  (struct mach_header *m, unsigned long s);
+static void darwin_unwind_dyld_remove_image_hook 
+  (struct mach_header *m, unsigned long s);
+extern void __darwin_gcc3_preregister_frame_info (void);
+     
+static void
+darwin_unwind_dyld_add_image_hook (struct mach_header *mh, unsigned long slide)
+{
+  struct live_images *l = (struct live_images *)calloc (1, sizeof (*l));
+  l->mh = mh;
+  l->vm_slide = slide;
+  l->this_size = sizeof (*l);
+  l->next = (struct live_images *)
+	_keymgr_get_and_lock_processwide_ptr (KEYMGR_GCC3_LIVE_IMAGE_LIST);
+  _keymgr_set_and_unlock_processwide_ptr (KEYMGR_GCC3_LIVE_IMAGE_LIST, l);
+}
+
+static void
+darwin_unwind_dyld_remove_image_hook (struct mach_header *m, unsigned long s)
+{
+  struct live_images *top, **lip, *destroy = NULL;
+
+  /* Look for it in the list of live images and delete it.  */
+
+  top = (struct live_images *)
+	   _keymgr_get_and_lock_processwide_ptr (KEYMGR_GCC3_LIVE_IMAGE_LIST);
+  for (lip = &top; *lip != NULL; lip = &(*lip)->next)
+    {
+      if ((*lip)->mh == m && (*lip)->vm_slide == s)
+        {
+          destroy = *lip;
+          *lip = destroy->next;			/* unlink DESTROY  */
+
+          if (destroy->this_size != sizeof (*destroy))	/* sanity check  */
+            abort ();
+
+          break;
+        }
+    }
+  _keymgr_set_and_unlock_processwide_ptr (KEYMGR_GCC3_LIVE_IMAGE_LIST, top);
+
+  /* Now that we have unlinked this from the image list, toss it.  */
+  if (destroy != NULL)
+    {
+      if (destroy->destructor != NULL)
+	(*destroy->destructor) (destroy);
+      free (destroy);
+    }
+}
+
+void
+__darwin_gcc3_preregister_frame_info (void)
+{
+  const _Tinfo_Node *info;
+  _init_keymgr ();
+  info = (_Tinfo_Node *)__keymgr_global[2];
+  if (info != NULL)
+    {
+      if (info->major_version >= KEYMGR_API_MAJOR_GCC3)
+	return;
+      /* Otherwise, use our own add_image_hooks.  */
+    }
+
+  _dyld_register_func_for_add_image (darwin_unwind_dyld_add_image_hook);
+  _dyld_register_func_for_remove_image (darwin_unwind_dyld_remove_image_hook);
+}
+
+#endif  /* __ppc__ */
diff --git a/libgcc/config/rs6000/t-darwin b/libgcc/config/rs6000/t-darwin
index 0afe837b458..4541e4ed3ed 100644
--- a/libgcc/config/rs6000/t-darwin
+++ b/libgcc/config/rs6000/t-darwin
@@ -1 +1,6 @@
+DARWIN_EXTRA_CRT_BUILD_CFLAGS = -mlongcall -mmacosx-version-min=10.4
+
+crt2.o: $(srcdir)/config/rs6000/darwin-crt2.c
+	$(crt_compile) $(DARWIN_EXTRA_CRT_BUILD_CFLAGS) -c $<
+
 SHLIB_VERPFX = $(gcc_srcdir)/config/rs6000/darwin-libgcc
diff --git a/libgcc/config/t-darwin b/libgcc/config/t-darwin
new file mode 100644
index 00000000000..548f0e3d469
--- /dev/null
+++ b/libgcc/config/t-darwin
@@ -0,0 +1,4 @@
+# Pass -fno-tree-dominator-opts to work around bug 26840.
+crt3.o: $(srcdir)/config/darwin-crt3.c
+	$(crt_compile) \
+	  -fno-tree-dominator-opts $(DARWIN_EXTRA_CRT_BUILD_CFLAGS) -c $<