ARM EABI backtrace using unwind information.

2009-06-24  Maxim Kuvyrkov  <maxim@codesourcery.com>
            Mark Mitchell  <mark@codesourcery.com>
            Joseph Myers  <joseph@codesourcery.com>
            Kazu Hirata  <kazu@codesourcery.com>

	* sysdeps/arm/eabi/backtrace.c: New.
	* sysdeps/arm/eabi/Makefile (CFLAGS-backtrace.c): Add
	-funwind-tables.
	* sysdeps/arm/preconfigure: Add -fno-unwind-tables to CFLAGS.
	* sysdeps/unix/sysv/linux/arm/eabi/configure.in: Remove
	-fno-unwind-tables from CFLAGS.
	* sysdeps/unix/sysv/linux/arm/eabi/configure: Regenerate.
	* sysdeps/unix/sysv/linux/arm/eabi/nptl/unwind.h (_Unwind_Trace_Fn):
	Define.
	(_Unwind_Backtrace): Declare.

ChangeLog.arm

@@ -1,3 +1,19 @@
+2009-06-24  Maxim Kuvyrkov  <maxim@codesourcery.com>
+            Mark Mitchell  <mark@codesourcery.com>
+            Joseph Myers  <joseph@codesourcery.com>
+            Kazu Hirata  <kazu@codesourcery.com>
+
+	* sysdeps/arm/eabi/backtrace.c: New.
+	* sysdeps/arm/eabi/Makefile (CFLAGS-backtrace.c): Add
+	-funwind-tables.
+	* sysdeps/arm/preconfigure: Add -fno-unwind-tables to CFLAGS.
+	* sysdeps/unix/sysv/linux/arm/eabi/configure.in: Remove
+	-fno-unwind-tables from CFLAGS.
+	* sysdeps/unix/sysv/linux/arm/eabi/configure: Regenerate.
+	* sysdeps/unix/sysv/linux/arm/eabi/nptl/unwind.h (_Unwind_Trace_Fn):
+	Define.
+	(_Unwind_Backtrace): Declare.
+
 2009-05-18  Joseph Myers  <joseph@codesourcery.com>
 
 	* sysdeps/arm/____longjmp_chk.S (CHECK_SP): Use unsigned

sysdeps/arm/eabi/Makefile

@@ -11,6 +11,10 @@ static-only-routines += $(aeabi_constants)
 gen-as-const-headers += rtld-global-offsets.sym
 endif
 
+ifeq ($(subdir),debug)
+CFLAGS-backtrace.c += -funwind-tables
+endif
+
 ifeq ($(subdir),elf)
 sysdep_routines += aeabi_unwind_cpp_pr1 find_exidx
 shared-only-routines += aeabi_unwind_cpp_pr1

sysdeps/arm/eabi/backtrace.c

@@ -0,0 +1,126 @@
+/* Return backtrace of current program state.
+   Copyright (C) 2008, 2009 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Kazu Hirata <kazu@codesourcery.com>, 2008.
+
+   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 <bits/libc-lock.h>
+#include <dlfcn.h>
+#include <execinfo.h>
+#include <stdlib.h>
+#include <unwind.h>
+
+struct trace_arg
+{
+  void **array;
+  int cnt, size;
+};
+
+#ifdef SHARED
+static _Unwind_Reason_Code (*unwind_backtrace) (_Unwind_Trace_Fn, void *);
+static _Unwind_VRS_Result (*unwind_vrs_get) (_Unwind_Context *,
+					     _Unwind_VRS_RegClass,
+					     _uw,
+					     _Unwind_VRS_DataRepresentation,
+					     void *);
+
+static void *libgcc_handle;
+
+static void
+init (void)
+{
+  libgcc_handle = __libc_dlopen ("libgcc_s.so.1");
+
+  if (libgcc_handle == NULL)
+    return;
+
+  unwind_backtrace = __libc_dlsym (libgcc_handle, "_Unwind_Backtrace");
+  unwind_vrs_get = __libc_dlsym (libgcc_handle, "_Unwind_VRS_Get");
+  if (unwind_vrs_get == NULL)
+    unwind_backtrace = NULL;
+}
+
+/* This function is identical to "_Unwind_GetGR", except that it uses
+   "unwind_vrs_get" instead of "_Unwind_VRS_Get".  */
+static inline _Unwind_Word
+unwind_getgr (_Unwind_Context *context, int regno)
+{
+  _uw val;
+  unwind_vrs_get (context, _UVRSC_CORE, regno, _UVRSD_UINT32, &val);
+  return val;
+}
+
+/* This macro is identical to the _Unwind_GetIP macro, except that it
+   uses "unwind_getgr" instead of "_Unwind_GetGR".  */
+# define unwind_getip(context) \
+  (unwind_getgr (context, 15) & ~(_Unwind_Word)1)
+#else
+# define unwind_backtrace _Unwind_Backtrace
+# define unwind_getip _Unwind_GetIP
+#endif
+
+static _Unwind_Reason_Code
+backtrace_helper (struct _Unwind_Context *ctx, void *a)
+{
+  struct trace_arg *arg = a;
+
+  /* We are first called with address in the __backtrace function.
+     Skip it.  */
+  if (arg->cnt != -1)
+    arg->array[arg->cnt] = (void *) unwind_getip (ctx);
+  if (++arg->cnt == arg->size)
+    return _URC_END_OF_STACK;
+  return _URC_NO_REASON;
+}
+
+int
+__backtrace (array, size)
+     void **array;
+     int size;
+{
+  struct trace_arg arg = { .array = array, .size = size, .cnt = -1 };
+#ifdef SHARED
+  __libc_once_define (static, once);
+
+  __libc_once (once, init);
+  if (unwind_backtrace == NULL)
+    return 0;
+#endif
+
+  if (size >= 1)
+    unwind_backtrace (backtrace_helper, &arg);
+
+  if (arg.cnt > 1 && arg.array[arg.cnt - 1] == NULL)
+    --arg.cnt;
+  return arg.cnt != -1 ? arg.cnt : 0;
+}
+weak_alias (__backtrace, backtrace)
+libc_hidden_def (__backtrace)
+
+
+#ifdef SHARED
+/* Free all resources if necessary.  */
+libc_freeres_fn (free_mem)
+{
+  unwind_backtrace = NULL;
+  if (libgcc_handle != NULL)
+    {
+      __libc_dlclose (libgcc_handle);
+      libgcc_handle = NULL;
+    }
+}
+#endif

sysdeps/arm/preconfigure

@@ -11,3 +11,7 @@ arm*)
 	esac
 	;;
 esac
+if [ "${CFLAGS+set}" != "set" ]; then
+  CFLAGS="-g -O2"
+fi
+CFLAGS="$CFLAGS -fno-unwind-tables"

sysdeps/unix/sysv/linux/arm/eabi/configure

@@ -3,3 +3,4 @@
 
 arch_minimum_kernel=2.6.16
 libc_cv_gcc_unwind_find_fde=no
+CFLAGS=${CFLAGS% -fno-unwind-tables}

sysdeps/unix/sysv/linux/arm/eabi/configure.in

@@ -3,3 +3,4 @@ GLIBC_PROVIDES dnl See aclocal.m4 in the top level source directory.
 
 arch_minimum_kernel=2.6.16
 libc_cv_gcc_unwind_find_fde=no
+CFLAGS=${CFLAGS% -fno-unwind-tables}

sysdeps/unix/sysv/linux/arm/eabi/nptl/unwind.h

@@ -1,5 +1,5 @@
 /* Header file for the ARM EABI unwinder
-   Copyright (C) 2003, 2004, 2005  Free Software Foundation, Inc.
+   Copyright (C) 2003, 2004, 2005, 2009  Free Software Foundation, Inc.
    Contributed by Paul Brook
 
    This file is free software; you can redistribute it and/or modify it
@@ -267,6 +267,11 @@ extern "C" {
 #define _Unwind_SetIP(context, val) \
   _Unwind_SetGR (context, 15, val | (_Unwind_GetGR (context, 15) & 1))
 
+typedef _Unwind_Reason_Code (*_Unwind_Trace_Fn)
+     (struct _Unwind_Context *, void *);
+
+extern _Unwind_Reason_Code _Unwind_Backtrace (_Unwind_Trace_Fn, void *);
+
 #ifdef __cplusplus
 }   /* extern "C" */
 #endif