1/* Signal trampoline unwinder, for GDB the GNU Debugger. 2 3 Copyright (C) 2004, 2007 Free Software Foundation, Inc. 4 5 This file is part of GDB. 6 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. 11 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. 16 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/>. */ 19 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" 29#include "gdb_assert.h" 30 31struct frame_data 32{ 33 const struct tramp_frame *tramp_frame; 34}; 35 36struct tramp_frame_cache 37{ 38 CORE_ADDR func; 39 const struct tramp_frame *tramp_frame; 40 struct trad_frame_cache *trad_cache; 41}; 42 43static struct trad_frame_cache * 44tramp_frame_cache (struct frame_info *next_frame, 45 void **this_cache) 46{ 47 CORE_ADDR pc = frame_pc_unwind (next_frame); 48 struct tramp_frame_cache *tramp_cache = (*this_cache); 49 if (tramp_cache->trad_cache == NULL) 50 { 51 tramp_cache->trad_cache = trad_frame_cache_zalloc (next_frame); 52 tramp_cache->tramp_frame->init (tramp_cache->tramp_frame, 53 next_frame, 54 tramp_cache->trad_cache, 55 tramp_cache->func); 56 } 57 return tramp_cache->trad_cache; 58} 59 60static void 61tramp_frame_this_id (struct frame_info *next_frame, 62 void **this_cache, 63 struct frame_id *this_id) 64{ 65 struct trad_frame_cache *trad_cache 66 = tramp_frame_cache (next_frame, this_cache); 67 trad_frame_get_id (trad_cache, this_id); 68} 69 70static void 71tramp_frame_prev_register (struct frame_info *next_frame, 72 void **this_cache, 73 int prev_regnum, 74 int *optimizedp, 75 enum lval_type * lvalp, 76 CORE_ADDR *addrp, 77 int *realnump, gdb_byte *valuep) 78{ 79 struct trad_frame_cache *trad_cache 80 = tramp_frame_cache (next_frame, this_cache); 81 trad_frame_get_register (trad_cache, next_frame, prev_regnum, optimizedp, 82 lvalp, addrp, realnump, valuep); 83} 84 85static CORE_ADDR 86tramp_frame_start (const struct tramp_frame *tramp, 87 struct frame_info *next_frame, CORE_ADDR pc) 88{ 89 int ti; 90 /* Search through the trampoline for one that matches the 91 instruction sequence around PC. */ 92 for (ti = 0; tramp->insn[ti].bytes != TRAMP_SENTINEL_INSN; ti++) 93 { 94 CORE_ADDR func = pc - tramp->insn_size * ti; 95 int i; 96 for (i = 0; 1; i++) 97 { 98 gdb_byte buf[sizeof (tramp->insn[0])]; 99 ULONGEST insn; 100 if (tramp->insn[i].bytes == TRAMP_SENTINEL_INSN) 101 return func; 102 if (!safe_frame_unwind_memory (next_frame, 103 func + i * tramp->insn_size, 104 buf, tramp->insn_size)) 105 break; 106 insn = extract_unsigned_integer (buf, tramp->insn_size); 107 if (tramp->insn[i].bytes != (insn & tramp->insn[i].mask)) 108 break; 109 } 110 } 111 /* Trampoline doesn't match. */ 112 return 0; 113} 114 115static int 116tramp_frame_sniffer (const struct frame_unwind *self, 117 struct frame_info *next_frame, 118 void **this_cache) 119{ 120 const struct tramp_frame *tramp = self->unwind_data->tramp_frame; 121 CORE_ADDR pc = frame_pc_unwind (next_frame); 122 CORE_ADDR func; 123 struct tramp_frame_cache *tramp_cache; 124 125 /* tausq/2004-12-12: We used to assume if pc has a name or is in a valid 126 section, then this is not a trampoline. However, this assumption is 127 false on HPUX which has a signal trampoline that has a name; it can 128 also be false when using an alternative signal stack. */ 129 func = tramp_frame_start (tramp, next_frame, pc); 130 if (func == 0) 131 return 0; 132 tramp_cache = FRAME_OBSTACK_ZALLOC (struct tramp_frame_cache); 133 tramp_cache->func = func; 134 tramp_cache->tramp_frame = tramp; 135 (*this_cache) = tramp_cache; 136 return 1; 137} 138 139void 140tramp_frame_prepend_unwinder (struct gdbarch *gdbarch, 141 const struct tramp_frame *tramp_frame) 142{ 143 struct frame_data *data; 144 struct frame_unwind *unwinder; 145 int i; 146 147 /* Check that the instruction sequence contains a sentinel. */ 148 for (i = 0; i < ARRAY_SIZE (tramp_frame->insn); i++) 149 { 150 if (tramp_frame->insn[i].bytes == TRAMP_SENTINEL_INSN) 151 break; 152 } 153 gdb_assert (i < ARRAY_SIZE (tramp_frame->insn)); 154 gdb_assert (tramp_frame->insn_size <= sizeof (tramp_frame->insn[0].bytes)); 155 156 data = GDBARCH_OBSTACK_ZALLOC (gdbarch, struct frame_data); 157 unwinder = GDBARCH_OBSTACK_ZALLOC (gdbarch, struct frame_unwind); 158 159 data->tramp_frame = tramp_frame; 160 unwinder->type = tramp_frame->frame_type; 161 unwinder->unwind_data = data; 162 unwinder->sniffer = tramp_frame_sniffer; 163 unwinder->this_id = tramp_frame_this_id; 164 unwinder->prev_register = tramp_frame_prev_register; 165 frame_unwind_prepend_unwinder (gdbarch, unwinder); 166} 167