diff -Nrup a/memstomp.c b/memstomp.c

--- a/memstomp.c	2014-08-26 13:13:30.004485804 -0600

+++ b/memstomp.c	2014-08-26 13:17:00.450138891 -0600

@@ -241,6 +241,16 @@ static char* generate_stacktrace(void)

         int const n = real_backtrace(retaddr, frames_max);

         assert(n >= 0);

+	/* Adjust the frame addresses since they point to the next

+	   instruction to execute, not the call site which may be

+	   associated with different line numbers. 

+

+	   For the cases we care about in memstomp, just subtracting

+	   1 works the vast majority of the time.  It may not work for

+	   a tail-call into an intercepted routine though.  */

+	for (int i = 0; i < n; i++)

+		retaddr[i]--;

+	    

         char **const strings = real_backtrace_symbols(retaddr, n);

         assert(strings);

diff -Nrup a/testsuite/lib/memstomp.exp b/testsuite/lib/memstomp.exp

--- a/testsuite/lib/memstomp.exp	2014-08-26 13:13:29.964485869 -0600

+++ b/testsuite/lib/memstomp.exp	2014-08-26 14:29:37.334241044 -0600

@@ -13,3 +13,11 @@ proc find_libmemstomp {} {

   set file [findfile $base_dir/../.libs/libmemstomp.so $base_dir/../.libs/libmemstomp.so libmemstomp.so]

   return $file

 }

+

+proc find_libmemstomp_backtrace_symbols {} {

+  global tool_root_dir 

+  global base_dir

+

+  set file [findfile $base_dir/../.libs/libmemstomp-backtrace-symbols.so $base_dir/../.libs/libmemstomp-backtrace-symbols.so libmemstomp-backtrace-symbols.so]

+  return $file

+}

diff -Nrup a/testsuite/memstomp.lineinfo/linenumber.c b/testsuite/memstomp.lineinfo/linenumber.c

--- a/testsuite/memstomp.lineinfo/linenumber.c	1969-12-31 17:00:00.000000000 -0700

+++ b/testsuite/memstomp.lineinfo/linenumber.c	2014-08-26 13:23:12.535518727 -0600

@@ -0,0 +1,23 @@

+#define __NO_STRING_INLINES

+#include <string.h>

+

+void

+something (void)

+{

+  char a[20] = "     hello";

+  memcpy (a, a + 5, 6);

+}

+

+void

+nothing (void)

+{

+  something ();

+}

+

+int

+main (void)

+{

+  nothing ();

+  return 0;

+}

+

diff -Nrup a/testsuite/memstomp.lineinfo/linenumber.exp b/testsuite/memstomp.lineinfo/linenumber.exp

--- a/testsuite/memstomp.lineinfo/linenumber.exp	1969-12-31 17:00:00.000000000 -0700

+++ b/testsuite/memstomp.lineinfo/linenumber.exp	2014-08-26 17:49:55.493353200 -0600

@@ -0,0 +1,65 @@

+# Copyright (C) 2014 Free Software Foundation, Inc.

+

+# This program 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 of the License, or

+# (at your option) any later version.

+#

+# This program 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.

+#

+# You should have received a copy of the GNU General Public License

+# along with GCC; see the file COPYING3.  If not see

+# <http://www.gnu.org/licenses/>.

+#

+# This was originally copied from GCC's dejagnu testing framework

+#

+# This is a hack.  If we need more of these tests we'll want to use

+# something like dj's framework so that we can mark the lines where

+# we want errors/warnings.

+#

+

+load_lib memstomp.exp

+set libmemstomp [find_libmemstomp]

+set libmemstomp_backtrace_symbols [find_libmemstomp_backtrace_symbols]

+

+if $tracelevel then {

+    strace $tracelevel

+}

+

+#

+# main test loop

+#

+

+proc compile-and-execute { sources } {

+  global libmemstomp

+  global libmemstomp_backtrace_symbols

+

+  set src [lindex $sources 0]

+

+  if {[catch {exec gcc -g -fno-builtin $src} results]} {

+    fail "$src compilation $results"

+  } else {

+    pass "$src compilation $results"

+  }

+

+  # ARM's unwinder seems broken

+  setup_xfail arm*-*-*

+  catch {exec /bin/bash -c "LD_PRELOAD=$libmemstomp:$libmemstomp_backtrace_symbols ./a.out"} results

+  if {[regexp "linenumber.c:8" $results]} {

+    pass "$src found overlap on right line $results"

+  } else {

+    fail "$src found overlap on right line $results"

+  }

+}

+

+foreach src [lsort [glob -nocomplain $srcdir/$subdir/*.c]] {

+    # If we're only testing specific files and this isn't one of them, skip it.

+    if ![runtest_file_p $runtests $src] then {

+        continue

+    }

+

+   compile-and-execute $src

+}

diff -Nrup a/testsuite/memstomp.overlap/linenumber.c b/testsuite/memstomp.overlap/linenumber.c

--- a/testsuite/memstomp.overlap/linenumber.c	1969-12-31 17:00:00.000000000 -0700

+++ b/testsuite/memstomp.overlap/linenumber.c	2014-08-26 13:17:30.057090085 -0600

@@ -0,0 +1,23 @@

+#define __NO_STRING_INLINES

+#include <string.h>

+

+void

+something (void)

+{

+  char a[20] = "     hello";

+  memcpy (a, a + 5, 6);

+}

+

+void

+nothing (void)

+{

+  something ();

+}

+

+int

+main (void)

+{

+  nothing ();

+  return 0;

+}

+