* trouble.texi (Crashing): Document addr2line.

doc/emacs/ChangeLog

+2012-09-21  Paul Eggert  <eggert@cs.ucla.edu>
+
+	* trouble.texi (Crashing): Document addr2line.
+
 2012-09-19  Chong Yidong  <cyd@gnu.org>
 
 	* killing.texi (Yanking): Minor clarification (Bug#12469).

doc/emacs/trouble.texi

@@ -308,13 +308,26 @@ emacs[0x565151]
 
 @noindent
 The number @samp{11} is the system signal number that corresponds to
-the problem, a segmentation fault here.  The hexadecimal program
-addresses can be useful in debugging sessions.  For example, the GDB
-command @samp{list *0x509af6} prints the source-code lines
-corresponding to the @samp{emacs[0x509af6]} entry in the backtrace.
+the problem, a segmentation fault here.  The three dots at the end
+indicate that Emacs suppressed further backtrace entries, in the
+interest of brevity.
 
-The three dots at the end indicate that Emacs suppressed further
-backtrace entries, in the interest of brevity.
+The hexadecimal program addresses can be useful in debugging sessions.
+For example, the GDB command @samp{list *0x509af6} prints the
+source-code lines corresponding to the @samp{emacs[0x509af6]} entry in
+the backtrace.  Or, if your system has @command{addr2line}, the
+following shell command outputs a backtrace with source-code line
+numbers:
+
+@example
+sed -n 's/.*\[\(.*\)]$/\1/p' @var{backtrace} |
+  addr2line -Cfip -e @var{bindir}/emacs
+@end example
+
+@noindent
+Here, @var{backtrace} is the name of a text file containing a copy of
+the backtrace, and @var{bindir} is the name of the directory that
+contains the Emacs executable.
 
 @node After a Crash
 @subsection Recovery After a Crash