tb-gcc.c: GCC infrastructure based implementation of __gnat_backtrace.

	* tb-gcc.c: GCC infrastructure based implementation of
	__gnat_backtrace.

From-SVN: r91290

2 files changed, 107 insertions, 0 deletions

diff --git a/gcc/ada/ChangeLog b/gcc/ada/ChangeLog
index 5769f8b..b10aaf0 100644
--- a/gcc/ada/ChangeLog
+++ b/gcc/ada/ChangeLog
@@ -1,3 +1,8 @@
+2004-11-25  Olivier Hainque  <hainque@adacore.com>
+
+	* tb-gcc.c: GCC infrastructure based implementation of
+	__gnat_backtrace.
+
 2004-11-24  Steven Bosscher  <stevenb@suse.de>
 
 	* misc.c (gnat_post_options): Don't clear
diff --git a/gcc/ada/tb-gcc.c b/gcc/ada/tb-gcc.c
new file mode 100644
index 0000000..ca0da9c
--- /dev/null
+++ b/gcc/ada/tb-gcc.c
@@ -0,0 +1,102 @@
+/****************************************************************************
+ *                                                                          *
+ *                         GNAT COMPILER COMPONENTS                         *
+ *                                                                          *
+ *                   T R A C E B A C K - G C C t a b l e s                  *
+ *                                                                          *
+ *                          C Implementation File                           *
+ *                                                                          *
+ *              Copyright (C) 2004 Ada Core Technologies, Inc               *
+ *                                                                          *
+ * GNAT is free software;  you can  redistribute it  and/or modify it under *
+ * terms of the  GNU General Public License as published  by the Free Soft- *
+ * ware  Foundation;  either version 2,  or (at your option) any later ver- *
+ * sion.  GNAT is distributed in the hope that it will be useful, but WITH- *
+ * OUT 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  distributed with GNAT;  see file COPYING.  If not, write *
+ * to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, *
+ * MA 02111-1307, USA.                                                      *
+ *                                                                          *
+ * As a  special  exception,  if you  link  this file  with other  files to *
+ * produce an executable,  this file does not by itself cause the resulting *
+ * executable to be covered by the GNU General Public License. This except- *
+ * ion does not  however invalidate  any other reasons  why the  executable *
+ * file might be covered by the  GNU Public License.                        *
+ *                                                                          *
+ * GNAT was originally developed  by the GNAT team at  New York University. *
+ * Extensive contributions were provided by Ada Core Technologies Inc.      *
+ *                                                                          *
+ ****************************************************************************/
+
+/* This is an implementation of the __gnat_backtrace routine using the
+   underlying GCC unwinding support associated with the exception handling
+   infrastructure.  This will only work for ZCX based applications.  */
+
+#include <unwind.h>
+
+/* The implementation boils down to a call to _Unwind_Backtrace with a
+   tailored callback and carried-on datastructure to keep track of the
+   input parameters we got as well as of the basic processing state.  */
+
+typedef struct {
+  void ** traceback;
+  int max_len;
+  void * exclude_min;
+  void * exclude_max;
+  int  n_frames_to_skip;
+  int  n_frames_skipped;
+  int  n_entries_filled;
+} uw_data_t;
+
+/******************
+ * trace_callback *
+ ******************/
+
+static _Unwind_Reason_Code
+trace_callback (struct _Unwind_Context * uw_context, uw_data_t * uw_data)
+{
+  void * pc = (void *) _Unwind_GetIP (uw_context);
+
+  if (uw_data->n_frames_skipped < uw_data->n_frames_to_skip)
+    {
+      uw_data->n_frames_skipped ++;
+      return _URC_NO_REASON;
+    }
+
+  if (uw_data->n_entries_filled >= uw_data->max_len)
+    return _URC_NORMAL_STOP;
+
+  if (pc < uw_data->exclude_min || pc > uw_data->exclude_max)
+    uw_data->traceback [uw_data->n_entries_filled ++] = pc + PC_ADJUST;
+
+  return _URC_NO_REASON;
+}
+
+/********************
+ * __gnat_backtrace *
+ ********************/
+
+int
+__gnat_backtrace (void ** traceback, int max_len,
+		  void * exclude_min, void * exclude_max,
+		  int  skip_frames)
+{
+  uw_data_t uw_data;
+  /* State carried over during the whole unwinding process.  */
+
+  uw_data.traceback   = traceback;
+  uw_data.max_len     = max_len;
+  uw_data.exclude_min = exclude_min;
+  uw_data.exclude_max = exclude_max;
+
+  uw_data.n_frames_to_skip = skip_frames;
+
+  uw_data.n_frames_skipped = 0;
+  uw_data.n_entries_filled = 0;
+
+  _Unwind_Backtrace ((_Unwind_Trace_Fn)trace_callback, &uw_data);
+
+  return uw_data.n_entries_filled;
+}