gdb/tramp-frame.c - gdb

Data types defined

Functions defined

Source code

  1. /* Signal trampoline unwinder, for GDB the GNU Debugger.

  3.    Copyright (C) 2004-2015 Free Software Foundation, Inc.

  5.    This file is part of GDB.

  7.    This program is free software; you can redistribute it and/or modify
  8.    it under the terms of the GNU General Public License as published by
  9.    the Free Software Foundation; either version 3 of the License, or
  10.    (at your option) any later version.

  12.    This program is distributed in the hope that it will be useful,
  13.    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14.    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15.    GNU General Public License for more details.

  17.    You should have received a copy of the GNU General Public License
  18.    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

  20. #include "defs.h"
  21. #include "tramp-frame.h"
  22. #include "frame-unwind.h"
  23. #include "gdbcore.h"
  24. #include "symtab.h"
  25. #include "objfiles.h"
  26. #include "target.h"
  27. #include "trad-frame.h"
  28. #include "frame-base.h"

  30. ‌struct frame_data
  31. {
  32.   const struct tramp_frame *tramp_frame;
  33. };

  35. ‌struct tramp_frame_cache
  36. {
  37.   CORE_ADDR func;
  38.   const struct tramp_frame *tramp_frame;
  39.   struct trad_frame_cache *trad_cache;
  40. };

  42. static struct trad_frame_cache *
  43. ‌tramp_frame_cache (struct frame_info *this_frame,
  44.                    void **this_cache)
  45. {
  46.   struct tramp_frame_cache *tramp_cache = (*this_cache);

  48.   if (tramp_cache->trad_cache == NULL)
  49.     {
  50.       tramp_cache->trad_cache = trad_frame_cache_zalloc (this_frame);
  51.       tramp_cache->tramp_frame->init (tramp_cache->tramp_frame,
  52.                                       this_frame,
  53.                                       tramp_cache->trad_cache,
  54.                                       tramp_cache->func);
  55.     }
  56.   return tramp_cache->trad_cache;
  57. }

  59. static void
  60. ‌tramp_frame_this_id (struct frame_info *this_frame,
  61.                      void **this_cache,
  62.                      struct frame_id *this_id)
  63. {
  64.   struct trad_frame_cache *trad_cache
  65.     = tramp_frame_cache (this_frame, this_cache);

  67.   trad_frame_get_id (trad_cache, this_id);
  68. }

  70. static struct value *
  71. ‌tramp_frame_prev_register (struct frame_info *this_frame,
  72.                            void **this_cache,
  73.                            int prev_regnum)
  74. {
  75.   struct trad_frame_cache *trad_cache
  76.     = tramp_frame_cache (this_frame, this_cache);

  78.   return trad_frame_get_register (trad_cache, this_frame, prev_regnum);
  79. }

  81. static CORE_ADDR
  82. ‌tramp_frame_start (const struct tramp_frame *tramp,
  83.                    struct frame_info *this_frame, CORE_ADDR pc)
  84. {
  85.   struct gdbarch *gdbarch = get_frame_arch (this_frame);
  86.   enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
  87.   int ti;

  89.   /* Check if we can use this trampoline.  */
  90.   if (tramp->validate && !tramp->validate (tramp, this_frame, &pc))
  91.     return 0;

  93.   /* Search through the trampoline for one that matches the
  94.      instruction sequence around PC.  */
  95.   for (ti = 0; tramp->insn[ti].bytes != TRAMP_SENTINEL_INSN; ti++)
  96.     {
  97.       CORE_ADDR func = pc - tramp->insn_size * ti;
  98.       int i;

  100.       for (i = 0; 1; i++)
  101.         {
  102.           gdb_byte buf[sizeof (tramp->insn[0])];
  103.           ULONGEST insn;

  105.           if (tramp->insn[i].bytes == TRAMP_SENTINEL_INSN)
  106.             return func;
  107.           if (!safe_frame_unwind_memory (this_frame,
  108.                                          func + i * tramp->insn_size,
  109.                                          buf, tramp->insn_size))
  110.             break;
  111.           insn = extract_unsigned_integer (buf, tramp->insn_size, byte_order);
  112.           if (tramp->insn[i].bytes != (insn & tramp->insn[i].mask))
  113.             break;
  114.         }
  115.     }
  116.   /* Trampoline doesn't match.  */
  117.   return 0;
  118. }

  120. static int
  121. ‌tramp_frame_sniffer (const struct frame_unwind *self,
  122.                      struct frame_info *this_frame,
  123.                      void **this_cache)
  124. {
  125.   const struct tramp_frame *tramp = self->unwind_data->tramp_frame;
  126.   CORE_ADDR pc = get_frame_pc (this_frame);
  127.   CORE_ADDR func;
  128.   struct tramp_frame_cache *tramp_cache;

  130.   /* tausq/2004-12-12: We used to assume if pc has a name or is in a valid
  131.      section, then this is not a trampoline.  However, this assumption is
  132.      false on HPUX which has a signal trampoline that has a name; it can
  133.      also be false when using an alternative signal stack.  */
  134.   func = tramp_frame_start (tramp, this_frame, pc);
  135.   if (func == 0)
  136.     return 0;
  137.   tramp_cache = FRAME_OBSTACK_ZALLOC (struct tramp_frame_cache);
  138.   tramp_cache->func = func;
  139.   tramp_cache->tramp_frame = tramp;
  140.   (*this_cache) = tramp_cache;
  141.   return 1;
  142. }

  144. void
  145. ‌tramp_frame_prepend_unwinder (struct gdbarch *gdbarch,
  146.                               const struct tramp_frame *tramp_frame)
  147. {
  148.   struct frame_data *data;
  149.   struct frame_unwind *unwinder;
  150.   int i;

  152.   /* Check that the instruction sequence contains a sentinel.  */
  153.   for (i = 0; i < ARRAY_SIZE (tramp_frame->insn); i++)
  154.     {
  155.       if (tramp_frame->insn[i].bytes == TRAMP_SENTINEL_INSN)
  156.         break;
  157.     }
  158.   gdb_assert (i < ARRAY_SIZE (tramp_frame->insn));
  159.   gdb_assert (tramp_frame->insn_size <= sizeof (tramp_frame->insn[0].bytes));

  161.   data = GDBARCH_OBSTACK_ZALLOC (gdbarch, struct frame_data);
  162.   unwinder = GDBARCH_OBSTACK_ZALLOC (gdbarch, struct frame_unwind);

  164.   data->tramp_frame = tramp_frame;
  165.   unwinder->type = tramp_frame->frame_type;
  166.   unwinder->unwind_data = data;
  167.   unwinder->sniffer = tramp_frame_sniffer;
  168.   unwinder->stop_reason = default_frame_unwind_stop_reason;
  169.   unwinder->this_id = tramp_frame_this_id;
  170.   unwinder->prev_register = tramp_frame_prev_register;
  171.   frame_unwind_prepend_unwinder (gdbarch, unwinder);
  172. }