tb-gcc.c (uw_data_t, [...]): Only define if not GCC-SJLJ eh.

2007-12-06  Olivier Hainque  <hainque@adacore.com>

	* tb-gcc.c (uw_data_t, trace_callback): Only define if not GCC-SJLJ eh.
	(__gnat_backtrace): Early return 0 if using GCC-SJLJ eh.

From-SVN: r130874

gcc/ada/tb-gcc.c

@@ -6,7 +6,7 @@
  *                                                                          *
  *                          C Implementation File                           *
  *                                                                          *
- *                     Copyright (C) 2004-2005, AdaCore                     *
+ *                     Copyright (C) 2004-2007, AdaCore                     *
  *                                                                          *
  * 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- *
@@ -40,6 +40,12 @@
    tailored callback and carried-on datastructure to keep track of the
    input parameters we got as well as of the basic processing state.  */
 
+/******************
+ * trace_callback *
+ ******************/
+
+#if !defined (__USING_SJLJ_EXCEPTIONS__)
+
 typedef struct {
   void ** traceback;
   int max_len;
@@ -50,10 +56,6 @@ typedef struct {
   int  n_entries_filled;
 } uw_data_t;
 
-/******************
- * trace_callback *
- ******************/
-
 #if defined (__ia64__) && defined (__hpux__)
 #include <uwx.h>
 #endif
@@ -85,6 +87,8 @@ trace_callback (struct _Unwind_Context * uw_context, uw_data_t * uw_data)
   return _URC_NO_REASON;
 }
 
+#endif
+
 /********************
  * __gnat_backtrace *
  ********************/
@@ -94,6 +98,12 @@ __gnat_backtrace (void ** traceback, int max_len,
 		  void * exclude_min, void * exclude_max,
 		  int  skip_frames)
 {
+#if defined (__USING_SJLJ_EXCEPTIONS__)
+  /* We have no unwind material (tables) at hand with sjlj eh, and no
+     way to retrieve complete and accurate call chain information from
+     the context stack we maintain.  */
+  return 0;
+#else
   uw_data_t uw_data;
   /* State carried over during the whole unwinding process.  */
 
@@ -110,4 +120,5 @@ __gnat_backtrace (void ** traceback, int max_len,
   _Unwind_Backtrace ((_Unwind_Trace_Fn)trace_callback, &uw_data);
 
   return uw_data.n_entries_filled;
+#endif
 }