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 Ada Core Technologies, Inc               *
  10  *                                                                          *
  11  * GNAT is free software;  you can  redistribute it  and/or modify it under *
  12  * terms of the  GNU General Public License as published  by the Free Soft- *
  13  * ware  Foundation;  either version 2,  or (at your option) any later ver- *
  14  * sion.  GNAT is distributed in the hope that it will be useful, but WITH- *
  15  * OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY *
  16  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License *
  17  * for  more details.  You should have  received  a copy of the GNU General *
  18  * Public License  distributed with GNAT;  see file COPYING.  If not, write *
  19  * to  the  Free Software Foundation,  51  Franklin  Street,  Fifth  Floor, *
  20  * Boston, MA 02110-1301, USA.                                              *
  21  *                                                                          *
  22  * As a  special  exception,  if you  link  this file  with other  files to *
  23  * produce an executable,  this file does not by itself cause the resulting *
  24  * executable to be covered by the GNU General Public License. This except- *
  25  * ion does not  however invalidate  any other reasons  why the  executable *
  26  * file might be covered by the  GNU Public License.                        *
  27  *                                                                          *
  28  * GNAT was originally developed  by the GNAT team at  New York University. *
  29  * Extensive contributions were provided by Ada Core Technologies Inc.      *
  30  *                                                                          *
  31  ****************************************************************************/
  32
  33 /* This is an implementation of the __gnat_backtrace routine using the
  34    underlying GCC unwinding support associated with the exception handling
  35    infrastructure.  This will only work for ZCX based applications.  */
  36
  37 #include <unwind.h>
  38
  39 /* The implementation boils down to a call to _Unwind_Backtrace with a
  40    tailored callback and carried-on datastructure to keep track of the
  41    input parameters we got as well as of the basic processing state.  */
  42
  43 typedef struct {
  44   void ** traceback;
  45   int max_len;
  46   void * exclude_min;
  47   void * exclude_max;
  48   int  n_frames_to_skip;
  49   int  n_frames_skipped;
  50   int  n_entries_filled;
  51 } uw_data_t;
  52
  53 /******************
  54  * trace_callback *
  55  ******************/
  56
  57 static _Unwind_Reason_Code
  58 trace_callback (struct _Unwind_Context * uw_context, uw_data_t * uw_data)
  59 {
  60   void * pc = (void *) _Unwind_GetIP (uw_context);
  61
  62   if (uw_data->n_frames_skipped < uw_data->n_frames_to_skip)
  63     {
  64       uw_data->n_frames_skipped ++;
  65       return _URC_NO_REASON;
  66     }
  67
  68   if (uw_data->n_entries_filled >= uw_data->max_len)
  69     return _URC_NORMAL_STOP;
  70
  71   if (pc < uw_data->exclude_min || pc > uw_data->exclude_max)
  72     uw_data->traceback [uw_data->n_entries_filled ++] = pc + PC_ADJUST;
  73
  74   return _URC_NO_REASON;
  75 }
  76
  77 /********************
  78  * __gnat_backtrace *
  79  ********************/
  80
  81 int
  82 __gnat_backtrace (void ** traceback, int max_len,
  83                   void * exclude_min, void * exclude_max,
  84                   int  skip_frames)
  85 {
  86   uw_data_t uw_data;
  87   /* State carried over during the whole unwinding process.  */
  88
  89   uw_data.traceback   = traceback;
  90   uw_data.max_len     = max_len;
  91   uw_data.exclude_min = exclude_min;
  92   uw_data.exclude_max = exclude_max;
  93
  94   uw_data.n_frames_to_skip = skip_frames;
  95
  96   uw_data.n_frames_skipped = 0;
  97   uw_data.n_entries_filled = 0;
  98
  99   _Unwind_Backtrace ((_Unwind_Trace_Fn)trace_callback, &uw_data);
 100
 101   return uw_data.n_entries_filled;
 102 }