[patches] Additional backtrace test

["Joseph S. Myers" <joseph@xxxxxxxxxxxxxxxx>]

I've applied this patch to add a testcase that verifies that the backtrace 
function actually works (rather than producing an incorrect or incomplete 
backtrace, which the previously existing testcase would allow).

Index: ports/sysdeps/arm/eabi/Makefile
===================================================================
--- ports/sysdeps/arm/eabi/Makefile	(revision 8595)
+++ ports/sysdeps/arm/eabi/Makefile	(working copy)
@@ -16,6 +16,7 @@
 
 ifeq ($(subdir),debug)
 CFLAGS-backtrace.c += -funwind-tables
+CFLAGS-tst-backtrace2.c += -funwind-tables
 endif
 
 ifeq ($(subdir),elf)
Index: ports/ChangeLog.eglibc
===================================================================
--- ports/ChangeLog.eglibc	(revision 8595)
+++ ports/ChangeLog.eglibc	(working copy)
@@ -1,3 +1,7 @@
+2009-06-24  Joseph Myers  <joseph@xxxxxxxxxxxxxxxx>
+
+	* sysdeps/arm/eabi/Makefile (CFLAGS-tst-backtrace2.c): Define.
+
 2009-05-22  Joseph Myers  <joseph@xxxxxxxxxxxxxxxx>
 
 	* sysdeps/powerpc/powerpc32/e500/fpu/__longjmp-common.S: Use
Index: libc/debug/Makefile
===================================================================
--- libc/debug/Makefile	(revision 8595)
+++ libc/debug/Makefile	(working copy)
@@ -126,10 +126,13 @@
 LDFLAGS-tst-lfschk5 = -lstdc++
 LDFLAGS-tst-lfschk6 = -lstdc++
 
+# backtrace_symbols only works if we link with -rdynamic.
+LDFLAGS-tst-backtrace2 = -rdynamic
+
 tests = tst-longjmp_chk test-strcpy_chk test-stpcpy_chk
 tests-$(OPTION_EGLIBC_LOCALE_CODE) \
       += tst-chk1 tst-chk2 tst-chk3 tst-lfschk1 tst-lfschk2 tst-lfschk3 
-tests-$(OPTION_EGLIBC_BACKTRACE) += backtrace-tst 
+tests-$(OPTION_EGLIBC_BACKTRACE) += backtrace-tst tst-backtrace2
 ifeq (yy,$(OPTION_EGLIBC_LOCALE_CODE)$(OPTION_EGLIBC_CXX_TESTS))
 tests += tst-chk4 tst-chk5 tst-chk6 tst-lfschk4 tst-lfschk5 tst-lfschk6
 endif
Index: libc/debug/tst-backtrace2.c
===================================================================
--- libc/debug/tst-backtrace2.c	(revision 0)
+++ libc/debug/tst-backtrace2.c	(revision 0)
@@ -0,0 +1,110 @@
+/* Copyright (C) 2009 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by CodeSourcery.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#include <execinfo.h>
+#include <search.h>
+#include <string.h>
+
+static int do_test (void);
+#define TEST_FUNCTION do_test ()
+#include "../test-skeleton.c"
+
+/* Set to a non-zero value if the test fails.  */
+int ret;
+
+/* Accesses to X are used to prevent optimization.  */
+volatile int x;
+
+/* Called if the test fails.  */
+#define FAIL() \
+  do { printf ("Failure on line %d\n", __LINE__); ret = 1; } while (0)
+
+/* The backtrace should include at least f1, f2, f3, and do_test.  */
+#define NUM_FUNCTIONS 4
+
+/* Use this attribute to prevent inlining, so that all expected frames
+   are present.  */
+#define NO_INLINE __attribute__((noinline))
+
+NO_INLINE void
+fn1 (void) 
+{
+  void *addresses[NUM_FUNCTIONS];
+  char **symbols;
+  int n;
+  int i;
+
+  /* Get the backtrace addresses.  */
+  n = backtrace (addresses, sizeof (addresses) / sizeof (addresses[0]));
+  printf ("Obtained backtrace with %d functions\n", n);
+  /*  Check that there are at least four functions.  */
+  if (n < NUM_FUNCTIONS)
+    {
+      FAIL ();
+      return;
+    }
+  /* Convert them to symbols.  */
+  symbols = backtrace_symbols (addresses, n);
+  /* Check that symbols were obtained.  */
+  if (symbols == NULL) 
+    {
+      FAIL ();
+      return;
+    }
+  for (i = 0; i < n; ++i)
+    printf ("Function %d: %s\n", i, symbols[i]);
+  /* Check that the function names obtained are accurate.  */
+  if (strstr (symbols[0], "fn1") == NULL)
+    {
+      FAIL ();
+      return;
+    }
+  /* Symbol names are not available for static functions, so we do not
+     check f2.  */
+  if (strstr (symbols[2], "fn3") == NULL)
+    {
+      FAIL ();
+      return;
+    }
+  /* Symbol names are not available for static functions, so we do not
+     check do_test.  */
+}
+
+NO_INLINE static int 
+fn2 (void) 
+{
+  fn1 ();
+  /* Prevent tail calls.  */
+  return x;
+}
+
+NO_INLINE int 
+fn3 (void)
+{
+  fn2();
+  /* Prevent tail calls.  */
+  return x;
+}
+
+NO_INLINE static int 
+do_test (void) 
+{
+  fn3 ();
+  return ret;
+}
Index: libc/ChangeLog.eglibc
===================================================================
--- libc/ChangeLog.eglibc	(revision 8595)
+++ libc/ChangeLog.eglibc	(working copy)
@@ -1,3 +1,9 @@
+2009-06-24  Mark Mitchell  <mark@xxxxxxxxxxxxxxxx>
+
+	* debug/Makefile (LDFLAGS-tst-backtrace2): Define.
+	(tests-$(OPTION_EGLIBC_BACKTRACE)): Add tst-backtrace2.
+	* debug/tst-backtrace2.c: New test.
+
 2009-06-23  Joseph Myers  <joseph@xxxxxxxxxxxxxxxx>
 
 	* nptl/nptl-init.c (sighandler_setxid): Remove duplicate decrement

-- 
Joseph S. Myers
joseph@xxxxxxxxxxxxxxxx