gcc/ada/tb-gcc.c

   1 /****************************************************************************
   2  *                                                                          *
   3  *                         GNAT RUN-TIME 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) 2004-2018, Free Software Foundation, 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 3,  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.                                     *
  17  *                                                                          *
  18  * As a special exception under Section 7 of GPL version 3, you are granted *
  19  * additional permissions described in the GCC Runtime Library Exception,   *
  20  * version 3.1, as published by the Free Software Foundation.               *
  21  *                                                                          *
  22  * You should have received a copy of the GNU General Public License and    *
  23  * a copy of the GCC Runtime Library Exception along with this program;     *
  24  * see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    *
  25  * <http://www.gnu.org/licenses/>.                                          *
  26  *                                                                          *
  27  * GNAT was originally developed  by the GNAT team at  New York University. *
  28  * Extensive contributions were provided by Ada Core Technologies Inc.      *
  29  *                                                                          *
  30  ****************************************************************************/
  31
  32 /* This is an implementation of the __gnat_backtrace routine using the
  33    underlying GCC unwinding support associated with the exception handling
  34    infrastructure.  This will only work for ZCX based applications.  */
  35
  36 #include <unwind.h>
  37
  38 /* The implementation boils down to a call to _Unwind_Backtrace with a
  39    tailored callback and carried-on data structure to keep track of the
  40    input parameters we got as well as of the basic processing state.  */
  41
  42 /******************
  43  * trace_callback *
  44  ******************/
  45
  46 #if !defined (__USING_SJLJ_EXCEPTIONS__)
  47
  48 typedef struct {
  49   void ** traceback;
  50   int max_len;
  51   void * exclude_min;
  52   void * exclude_max;
  53   int  n_frames_to_skip;
  54   int  n_frames_skipped;
  55   int  n_entries_filled;
  56 } uw_data_t;
  57
  58 #if defined (__ia64__) && defined (__hpux__)
  59 #include <uwx.h>
  60 #endif
  61
  62 static _Unwind_Reason_Code
  63 trace_callback (struct _Unwind_Context * uw_context, uw_data_t * uw_data)
  64 {
  65   char * pc;
  66
  67 #if defined (__ia64__) && defined (__hpux__) && defined (USE_LIBUNWIND_EXCEPTIONS)
  68   /* Work around problem with _Unwind_GetIP on ia64 HP-UX. */
  69   uwx_get_reg ((struct uwx_env *) uw_context, UWX_REG_IP, (uint64_t *) &pc);
  70 #else
  71   pc = (char *) _Unwind_GetIP (uw_context);
  72 #endif
  73
  74   if (uw_data->n_frames_skipped < uw_data->n_frames_to_skip)
  75     {
  76       uw_data->n_frames_skipped ++;
  77       return _URC_NO_REASON;
  78     }
  79
  80   if (uw_data->n_entries_filled >= uw_data->max_len)
  81     return _URC_NORMAL_STOP;
  82
  83   if (pc < (char *)uw_data->exclude_min || pc > (char *)uw_data->exclude_max)
  84     uw_data->traceback [uw_data->n_entries_filled ++] = pc + PC_ADJUST;
  85
  86   return _URC_NO_REASON;
  87 }
  88
  89 #endif
  90
  91 /********************
  92  * __gnat_backtrace *
  93  ********************/
  94
  95 int
  96 __gnat_backtrace (void ** traceback __attribute__((unused)),
  97                   int max_len __attribute__((unused)),
  98                   void * exclude_min __attribute__((unused)),
  99                   void * exclude_max __attribute__((unused)),
 100                   int skip_frames __attribute__((unused)))
 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 }