gcc/ada/tb-gcc.c

   1 /****************************************************************************
   2  *                                                                          *
   3  *                         GNAT COMPILER COMPONENTS                         *
   4  *                                                                          *
   5  *                   T R A C E B A C K - G C C t a b l e s                  *
   6  *                                                                          *
   7  *                          C Implementation File                           *
   8  *                                                                          *
   9  *                     Copyright (C) 2004-2007, AdaCore                     *
  10  *             Copyright (C) 2008, Free Software Foundation, Inc.           *
  11  *                                                                          *
  12  * GNAT is free software;  you can  redistribute it  and/or modify it under *
  13  * terms of the  GNU General Public License as published  by the Free Soft- *
  14  * ware  Foundation;  either version 2,  or (at your option) any later ver- *
  15  * sion.  GNAT is distributed in the hope that it will be useful, but WITH- *
  16  * OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY *
  17  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License *
  18  * for  more details.  You should have  received  a copy of the GNU General *
  19  * Public License  distributed with GNAT;  see file COPYING.  If not, write *
  20  * to  the  Free Software Foundation,  51  Franklin  Street,  Fifth  Floor, *
  21  * Boston, MA 02110-1301, USA.                                              *
  22  *                                                                          *
  23  * As a  special  exception,  if you  link  this file  with other  files to *
  24  * produce an executable,  this file does not by itself cause the resulting *
  25  * executable to be covered by the GNU General Public License. This except- *
  26  * ion does not  however invalidate  any other reasons  why the  executable *
  27  * file might be covered by the  GNU Public License.                        *
  28  *                                                                          *
  29  * GNAT was originally developed  by the GNAT team at  New York University. *
  30  * Extensive contributions were provided by Ada Core Technologies Inc.      *
  31  *                                                                          *
  32  ****************************************************************************/
  33
  34 /* This is an implementation of the __gnat_backtrace routine using the
  35    underlying GCC unwinding support associated with the exception handling
  36    infrastructure.  This will only work for ZCX based applications.  */
  37
  38 #include <unwind.h>
  39
  40 /* The implementation boils down to a call to _Unwind_Backtrace with a
  41    tailored callback and carried-on data structure to keep track of the
  42    input parameters we got as well as of the basic processing state.  */
  43
  44 /******************
  45  * trace_callback *
  46  ******************/
  47
  48 #if !defined (__USING_SJLJ_EXCEPTIONS__)
  49
  50 typedef struct {
  51   void ** traceback;
  52   int max_len;
  53   void * exclude_min;
  54   void * exclude_max;
  55   int  n_frames_to_skip;
  56   int  n_frames_skipped;
  57   int  n_entries_filled;
  58 } uw_data_t;
  59
  60 #if defined (__ia64__) && defined (__hpux__)
  61 #include <uwx.h>
  62 #endif
  63
  64 static _Unwind_Reason_Code
  65 trace_callback (struct _Unwind_Context * uw_context, uw_data_t * uw_data)
  66 {
  67   void * pc;
  68
  69 #if defined (__ia64__) && defined (__hpux__)
  70   /* Work around problem with _Unwind_GetIP on ia64 HP-UX. */
  71   uwx_get_reg ((struct uwx_env *) uw_context, UWX_REG_IP, (uint64_t *) &pc);
  72 #else
  73   pc = (void *) _Unwind_GetIP (uw_context);
  74 #endif
  75
  76   if (uw_data->n_frames_skipped < uw_data->n_frames_to_skip)
  77     {
  78       uw_data->n_frames_skipped ++;
  79       return _URC_NO_REASON;
  80     }
  81
  82   if (uw_data->n_entries_filled >= uw_data->max_len)
  83     return _URC_NORMAL_STOP;
  84
  85   if (pc < uw_data->exclude_min || pc > uw_data->exclude_max)
  86     uw_data->traceback [uw_data->n_entries_filled ++] = pc + PC_ADJUST;
  87
  88   return _URC_NO_REASON;
  89 }
  90
  91 #endif
  92
  93 /********************
  94  * __gnat_backtrace *
  95  ********************/
  96
  97 int
  98 __gnat_backtrace (void ** traceback, int max_len,
  99                   void * exclude_min, void * exclude_max,
 100                   int  skip_frames)
 101 {
 102 #if defined (__USING_SJLJ_EXCEPTIONS__)
 103   /* We have no unwind material (tables) at hand with sjlj eh, and no
 104      way to retrieve complete and accurate call chain information from
 105      the context stack we maintain.  */
 106   return 0;
 107 #else
 108   uw_data_t uw_data;
 109   /* State carried over during the whole unwinding process.  */
 110
 111   uw_data.traceback   = traceback;
 112   uw_data.max_len     = max_len;
 113   uw_data.exclude_min = exclude_min;
 114   uw_data.exclude_max = exclude_max;
 115
 116   uw_data.n_frames_to_skip = skip_frames;
 117
 118   uw_data.n_frames_skipped = 0;
 119   uw_data.n_entries_filled = 0;
 120
 121   _Unwind_Backtrace ((_Unwind_Trace_Fn)trace_callback, &uw_data);
 122
 123   return uw_data.n_entries_filled;
 124 #endif
 125 }