Use __executable_start to find start of text segment for profiling

* emacs.c (main) [PROFILING]: Use __executable_start if defined to
find start of text segment.
* dispnew.c (safe_bcopy): Don't define if HAVE___EXECUTABLE_START
is defined.

* configure.in: Check for __executable_start.

4 files changed, 19 insertions, 1 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 0ed773d1acd..50a9fcb8ba8 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,5 +1,10 @@
 2010-07-25  Andreas Schwab  <schwab@linux-m68k.org>
 
+        * emacs.c (main) [PROFILING]: Use __executable_start if defined to
+        find start of text segment.
+        * dispnew.c (safe_bcopy): Don't define if HAVE___EXECUTABLE_START
+        is defined.
+
         * callproc.c (set_initial_environment): Avoid unbalanced braces.
 
 2010-07-25  Ken Brown  <kbrown@cornell.edu>
diff --git a/src/config.in b/src/config.in
index 40b62633446..647c8804dff 100644
--- a/src/config.in
+++ b/src/config.in
@@ -801,6 +801,9 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 /* Define to 1 if you want to use the X window system. */
 #undef HAVE_X_WINDOWS
 
+/* Define to 1 if you have the `__executable_start' function. */
+#undef HAVE___EXECUTABLE_START
+
 /* Define to 1 if you have the `__fpending' function. */
 #undef HAVE___FPENDING
 
diff --git a/src/dispnew.c b/src/dispnew.c
index fe64143ec07..73aafe07d94 100644
--- a/src/dispnew.c
+++ b/src/dispnew.c
@@ -436,7 +436,7 @@ DEFUN ("dump-redisplay-history", Fdump_redisplay_history,
 #endif /* GLYPH_DEBUG == 0 */
 
 
-#ifdef PROFILING
+#if defined PROFILING && !HAVE___EXECUTABLE_START
 /* FIXME: only used to find text start for profiling.  */
 
 void
diff --git a/src/emacs.c b/src/emacs.c
index fbae7763877..a5d57116c4f 100644
--- a/src/emacs.c
+++ b/src/emacs.c
@@ -1747,9 +1747,18 @@ main (int argc, char **argv)
 #else
       extern char etext;
 #endif
+#ifdef HAVE___EXECUTABLE_START
+      /* This symbol is defined by GNU ld to the start of the text
+         segment.  */
+      extern char __executable_start[];
+#else
       extern void safe_bcopy ();
+#endif
 
       atexit (_mcleanup);
+#ifdef HAVE___EXECUTABLE_START
+      monstartup (__executable_start, &etext);
+#else
       /* This uses safe_bcopy because that function comes first in the
          Emacs executable.  It might be better to use something that
          gives the start of the text segment, but start_of_text is not
@@ -1757,6 +1766,7 @@ main (int argc, char **argv)
       /* FIXME: Does not work on architectures with function
          descriptors.  */
       monstartup (safe_bcopy, &etext);
+#endif
     }
   else
     moncontrol (0);