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- /* Signal trampoline unwinder, for GDB the GNU Debugger.
- Copyright (C) 2004-2022 Free Software Foundation, Inc.
- This file is part of GDB.
- This program is free software; you can redistribute it and/or modify
- it under the terms of the GNU General Public License as published by
- the Free Software Foundation; either version 3 of the License, or
- (at your option) any later version.
- This program is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- GNU General Public License for more details.
- You should have received a copy of the GNU General Public License
- along with this program. If not, see <http://www.gnu.org/licenses/>. */
- #include "defs.h"
- #include "tramp-frame.h"
- #include "frame-unwind.h"
- #include "gdbcore.h"
- #include "symtab.h"
- #include "objfiles.h"
- #include "target.h"
- #include "trad-frame.h"
- #include "frame-base.h"
- struct frame_data
- {
- const struct tramp_frame *tramp_frame;
- };
- struct tramp_frame_cache
- {
- CORE_ADDR func;
- const struct tramp_frame *tramp_frame;
- struct trad_frame_cache *trad_cache;
- };
- static struct trad_frame_cache *
- tramp_frame_cache (struct frame_info *this_frame,
- void **this_cache)
- {
- struct tramp_frame_cache *tramp_cache
- = (struct tramp_frame_cache *) *this_cache;
- if (tramp_cache->trad_cache == NULL)
- {
- tramp_cache->trad_cache = trad_frame_cache_zalloc (this_frame);
- tramp_cache->tramp_frame->init (tramp_cache->tramp_frame,
- this_frame,
- tramp_cache->trad_cache,
- tramp_cache->func);
- }
- return tramp_cache->trad_cache;
- }
- static void
- tramp_frame_this_id (struct frame_info *this_frame,
- void **this_cache,
- struct frame_id *this_id)
- {
- struct trad_frame_cache *trad_cache
- = tramp_frame_cache (this_frame, this_cache);
- trad_frame_get_id (trad_cache, this_id);
- }
- static struct value *
- tramp_frame_prev_register (struct frame_info *this_frame,
- void **this_cache,
- int prev_regnum)
- {
- struct trad_frame_cache *trad_cache
- = tramp_frame_cache (this_frame, this_cache);
- return trad_frame_get_register (trad_cache, this_frame, prev_regnum);
- }
- static CORE_ADDR
- tramp_frame_start (const struct tramp_frame *tramp,
- struct frame_info *this_frame, CORE_ADDR pc)
- {
- struct gdbarch *gdbarch = get_frame_arch (this_frame);
- enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
- int ti;
- /* Check if we can use this trampoline. */
- if (tramp->validate && !tramp->validate (tramp, this_frame, &pc))
- return 0;
- /* Search through the trampoline for one that matches the
- instruction sequence around PC. */
- for (ti = 0; tramp->insn[ti].bytes != TRAMP_SENTINEL_INSN; ti++)
- {
- CORE_ADDR func = pc - tramp->insn_size * ti;
- int i;
- for (i = 0; 1; i++)
- {
- gdb_byte buf[sizeof (tramp->insn[0])];
- ULONGEST insn;
- size_t insn_size = tramp->insn_size;
- if (tramp->insn[i].bytes == TRAMP_SENTINEL_INSN)
- return func;
- if (!safe_frame_unwind_memory (this_frame,
- func + i * insn_size,
- {buf, insn_size}))
- break;
- insn = extract_unsigned_integer (buf, insn_size, byte_order);
- if (tramp->insn[i].bytes != (insn & tramp->insn[i].mask))
- break;
- }
- }
- /* Trampoline doesn't match. */
- return 0;
- }
- static int
- tramp_frame_sniffer (const struct frame_unwind *self,
- struct frame_info *this_frame,
- void **this_cache)
- {
- const struct tramp_frame *tramp = self->unwind_data->tramp_frame;
- CORE_ADDR pc = get_frame_pc (this_frame);
- CORE_ADDR func;
- struct tramp_frame_cache *tramp_cache;
- /* tausq/2004-12-12: We used to assume if pc has a name or is in a valid
- section, then this is not a trampoline. However, this assumption is
- false on HPUX which has a signal trampoline that has a name; it can
- also be false when using an alternative signal stack. */
- func = tramp_frame_start (tramp, this_frame, pc);
- if (func == 0)
- return 0;
- tramp_cache = FRAME_OBSTACK_ZALLOC (struct tramp_frame_cache);
- tramp_cache->func = func;
- tramp_cache->tramp_frame = tramp;
- (*this_cache) = tramp_cache;
- return 1;
- }
- void
- tramp_frame_prepend_unwinder (struct gdbarch *gdbarch,
- const struct tramp_frame *tramp_frame)
- {
- struct frame_data *data;
- struct frame_unwind *unwinder;
- int i;
- /* Check that the instruction sequence contains a sentinel. */
- for (i = 0; i < ARRAY_SIZE (tramp_frame->insn); i++)
- {
- if (tramp_frame->insn[i].bytes == TRAMP_SENTINEL_INSN)
- break;
- }
- gdb_assert (i < ARRAY_SIZE (tramp_frame->insn));
- gdb_assert (tramp_frame->insn_size <= sizeof (tramp_frame->insn[0].bytes));
- data = GDBARCH_OBSTACK_ZALLOC (gdbarch, struct frame_data);
- unwinder = GDBARCH_OBSTACK_ZALLOC (gdbarch, struct frame_unwind);
- data->tramp_frame = tramp_frame;
- unwinder->type = tramp_frame->frame_type;
- unwinder->unwind_data = data;
- unwinder->sniffer = tramp_frame_sniffer;
- unwinder->stop_reason = default_frame_unwind_stop_reason;
- unwinder->this_id = tramp_frame_this_id;
- unwinder->prev_register = tramp_frame_prev_register;
- frame_unwind_prepend_unwinder (gdbarch, unwinder);
- }
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