1 /* Signal trampoline unwinder, for GDB the GNU Debugger. 2 3 Copyright (C) 2004-2013 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 31 struct frame_data 32 { 33 const struct tramp_frame *tramp_frame; 34 }; 35 36 struct tramp_frame_cache 37 { 38 CORE_ADDR func; 39 const struct tramp_frame *tramp_frame; 40 struct trad_frame_cache *trad_cache; 41 }; 42 43 static struct trad_frame_cache * 44 tramp_frame_cache (struct frame_info *this_frame, 45 void **this_cache) 46 { 47 struct tramp_frame_cache *tramp_cache = (*this_cache); 48 49 if (tramp_cache->trad_cache == NULL) 50 { 51 tramp_cache->trad_cache = trad_frame_cache_zalloc (this_frame); 52 tramp_cache->tramp_frame->init (tramp_cache->tramp_frame, 53 this_frame, 54 tramp_cache->trad_cache, 55 tramp_cache->func); 56 } 57 return tramp_cache->trad_cache; 58 } 59 60 static void 61 tramp_frame_this_id (struct frame_info *this_frame, 62 void **this_cache, 63 struct frame_id *this_id) 64 { 65 struct trad_frame_cache *trad_cache 66 = tramp_frame_cache (this_frame, this_cache); 67 68 trad_frame_get_id (trad_cache, this_id); 69 } 70 71 static struct value * 72 tramp_frame_prev_register (struct frame_info *this_frame, 73 void **this_cache, 74 int prev_regnum) 75 { 76 struct trad_frame_cache *trad_cache 77 = tramp_frame_cache (this_frame, this_cache); 78 79 return trad_frame_get_register (trad_cache, this_frame, prev_regnum); 80 } 81 82 static CORE_ADDR 83 tramp_frame_start (const struct tramp_frame *tramp, 84 struct frame_info *this_frame, CORE_ADDR pc) 85 { 86 struct gdbarch *gdbarch = get_frame_arch (this_frame); 87 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); 88 int ti; 89 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 97 for (i = 0; 1; i++) 98 { 99 gdb_byte buf[sizeof (tramp->insn[0])]; 100 ULONGEST insn; 101 102 if (tramp->insn[i].bytes == TRAMP_SENTINEL_INSN) 103 return func; 104 if (!safe_frame_unwind_memory (this_frame, 105 func + i * tramp->insn_size, 106 buf, tramp->insn_size)) 107 break; 108 insn = extract_unsigned_integer (buf, tramp->insn_size, byte_order); 109 if (tramp->insn[i].bytes != (insn & tramp->insn[i].mask)) 110 break; 111 } 112 } 113 /* Trampoline doesn't match. */ 114 return 0; 115 } 116 117 static int 118 tramp_frame_sniffer (const struct frame_unwind *self, 119 struct frame_info *this_frame, 120 void **this_cache) 121 { 122 const struct tramp_frame *tramp = self->unwind_data->tramp_frame; 123 CORE_ADDR pc = get_frame_pc (this_frame); 124 CORE_ADDR func; 125 struct tramp_frame_cache *tramp_cache; 126 127 /* tausq/2004-12-12: We used to assume if pc has a name or is in a valid 128 section, then this is not a trampoline. However, this assumption is 129 false on HPUX which has a signal trampoline that has a name; it can 130 also be false when using an alternative signal stack. */ 131 func = tramp_frame_start (tramp, this_frame, pc); 132 if (func == 0) 133 return 0; 134 tramp_cache = FRAME_OBSTACK_ZALLOC (struct tramp_frame_cache); 135 tramp_cache->func = func; 136 tramp_cache->tramp_frame = tramp; 137 (*this_cache) = tramp_cache; 138 return 1; 139 } 140 141 void 142 tramp_frame_prepend_unwinder (struct gdbarch *gdbarch, 143 const struct tramp_frame *tramp_frame) 144 { 145 struct frame_data *data; 146 struct frame_unwind *unwinder; 147 int i; 148 149 /* Check that the instruction sequence contains a sentinel. */ 150 for (i = 0; i < ARRAY_SIZE (tramp_frame->insn); i++) 151 { 152 if (tramp_frame->insn[i].bytes == TRAMP_SENTINEL_INSN) 153 break; 154 } 155 gdb_assert (i < ARRAY_SIZE (tramp_frame->insn)); 156 gdb_assert (tramp_frame->insn_size <= sizeof (tramp_frame->insn[0].bytes)); 157 158 data = GDBARCH_OBSTACK_ZALLOC (gdbarch, struct frame_data); 159 unwinder = GDBARCH_OBSTACK_ZALLOC (gdbarch, struct frame_unwind); 160 161 data->tramp_frame = tramp_frame; 162 unwinder->type = tramp_frame->frame_type; 163 unwinder->unwind_data = data; 164 unwinder->sniffer = tramp_frame_sniffer; 165 unwinder->stop_reason = default_frame_unwind_stop_reason; 166 unwinder->this_id = tramp_frame_this_id; 167 unwinder->prev_register = tramp_frame_prev_register; 168 frame_unwind_prepend_unwinder (gdbarch, unwinder); 169 } 170