| File: | src/gnu/usr.bin/binutils/gdb/tramp-frame.c |
| Warning: | line 49, column 13 Value stored to 'pc' during its initialization is never read |
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| 1 | /* Signal trampoline unwinder, for GDB the GNU Debugger. |
| 2 | |
| 3 | Copyright 2004 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 2 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, write to the Free Software |
| 19 | Foundation, Inc., 59 Temple Place - Suite 330, |
| 20 | Boston, MA 02111-1307, USA. */ |
| 21 | |
| 22 | #include "defs.h" |
| 23 | #include "tramp-frame.h" |
| 24 | #include "frame-unwind.h" |
| 25 | #include "gdbcore.h" |
| 26 | #include "symtab.h" |
| 27 | #include "objfiles.h" |
| 28 | #include "target.h" |
| 29 | #include "trad-frame.h" |
| 30 | #include "frame-base.h" |
| 31 | #include "gdb_assert.h" |
| 32 | |
| 33 | struct frame_data |
| 34 | { |
| 35 | const struct tramp_frame *tramp_frame; |
| 36 | }; |
| 37 | |
| 38 | struct tramp_frame_cache |
| 39 | { |
| 40 | CORE_ADDR func; |
| 41 | const struct tramp_frame *tramp_frame; |
| 42 | struct trad_frame_cache *trad_cache; |
| 43 | }; |
| 44 | |
| 45 | static struct trad_frame_cache * |
| 46 | tramp_frame_cache (struct frame_info *next_frame, |
| 47 | void **this_cache) |
| 48 | { |
| 49 | CORE_ADDR pc = frame_pc_unwind (next_frame); |
Value stored to 'pc' during its initialization is never read | |
| 50 | struct tramp_frame_cache *tramp_cache = (*this_cache); |
| 51 | if (tramp_cache->trad_cache == NULL((void*)0)) |
| 52 | { |
| 53 | tramp_cache->trad_cache = trad_frame_cache_zalloc (next_frame); |
| 54 | tramp_cache->tramp_frame->init (tramp_cache->tramp_frame, |
| 55 | next_frame, |
| 56 | tramp_cache->trad_cache, |
| 57 | tramp_cache->func); |
| 58 | } |
| 59 | return tramp_cache->trad_cache; |
| 60 | } |
| 61 | |
| 62 | static void |
| 63 | tramp_frame_this_id (struct frame_info *next_frame, |
| 64 | void **this_cache, |
| 65 | struct frame_id *this_id) |
| 66 | { |
| 67 | struct trad_frame_cache *trad_cache |
| 68 | = tramp_frame_cache (next_frame, this_cache); |
| 69 | trad_frame_get_id (trad_cache, this_id); |
| 70 | } |
| 71 | |
| 72 | static void |
| 73 | tramp_frame_prev_register (struct frame_info *next_frame, |
| 74 | void **this_cache, |
| 75 | int prev_regnum, |
| 76 | int *optimizedp, |
| 77 | enum lval_type * lvalp, |
| 78 | CORE_ADDR *addrp, |
| 79 | int *realnump, void *valuep) |
| 80 | { |
| 81 | struct trad_frame_cache *trad_cache |
| 82 | = tramp_frame_cache (next_frame, this_cache); |
| 83 | trad_frame_get_register (trad_cache, next_frame, prev_regnum, optimizedp, |
| 84 | lvalp, addrp, realnump, valuep); |
| 85 | } |
| 86 | |
| 87 | static CORE_ADDR |
| 88 | tramp_frame_start (const struct tramp_frame *tramp, |
| 89 | struct frame_info *next_frame, CORE_ADDR pc) |
| 90 | { |
| 91 | int ti; |
| 92 | /* Search through the trampoline for one that matches the |
| 93 | instruction sequence around PC. */ |
| 94 | for (ti = 0; tramp->insn[ti].bytes != TRAMP_SENTINEL_INSN((long) -1); ti++) |
| 95 | { |
| 96 | CORE_ADDR func = pc - tramp->insn_size * ti; |
| 97 | int i; |
| 98 | for (i = 0; 1; i++) |
| 99 | { |
| 100 | bfd_byte buf[sizeof (tramp->insn[0])]; |
| 101 | ULONGESTunsigned long insn; |
| 102 | if (tramp->insn[i].bytes == TRAMP_SENTINEL_INSN((long) -1)) |
| 103 | return func; |
| 104 | if (!safe_frame_unwind_memory (next_frame, |
| 105 | func + i * tramp->insn_size, |
| 106 | buf, tramp->insn_size)) |
| 107 | break; |
| 108 | insn = extract_unsigned_integer (buf, tramp->insn_size); |
| 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 *next_frame, |
| 120 | void **this_cache) |
| 121 | { |
| 122 | const struct tramp_frame *tramp = self->unwind_data->tramp_frame; |
| 123 | CORE_ADDR pc = frame_pc_unwind (next_frame); |
| 124 | CORE_ADDR func; |
| 125 | char *name; |
| 126 | struct tramp_frame_cache *tramp_cache; |
| 127 | |
| 128 | /* If the function has a valid symbol name, it isn't a |
| 129 | trampoline. */ |
| 130 | find_pc_partial_function (pc, &name, NULL((void*)0), NULL((void*)0)); |
| 131 | if (name != NULL((void*)0)) |
| 132 | return 0; |
| 133 | /* If the function lives in a valid section (even without a starting |
| 134 | point) it isn't a trampoline. */ |
| 135 | if (find_pc_section (pc) != NULL((void*)0)) |
| 136 | return 0; |
| 137 | /* Finally, check that the trampoline matches at PC. */ |
| 138 | func = tramp_frame_start (tramp, next_frame, pc); |
| 139 | if (func == 0) |
| 140 | return 0; |
| 141 | tramp_cache = FRAME_OBSTACK_ZALLOC (struct tramp_frame_cache)((struct tramp_frame_cache *) frame_obstack_zalloc (sizeof (struct tramp_frame_cache))); |
| 142 | tramp_cache->func = func; |
| 143 | tramp_cache->tramp_frame = tramp; |
| 144 | (*this_cache) = tramp_cache; |
| 145 | return 1; |
| 146 | } |
| 147 | |
| 148 | void |
| 149 | tramp_frame_prepend_unwinder (struct gdbarch *gdbarch, |
| 150 | const struct tramp_frame *tramp_frame) |
| 151 | { |
| 152 | struct frame_data *data; |
| 153 | struct frame_unwind *unwinder; |
| 154 | int i; |
| 155 | |
| 156 | /* Check that the instruction sequence contains a sentinel. */ |
| 157 | for (i = 0; i < ARRAY_SIZE (tramp_frame->insn)(sizeof (tramp_frame->insn) / sizeof ((tramp_frame->insn )[0])); i++) |
| 158 | { |
| 159 | if (tramp_frame->insn[i].bytes == TRAMP_SENTINEL_INSN((long) -1)) |
| 160 | break; |
| 161 | } |
| 162 | gdb_assert (i < ARRAY_SIZE (tramp_frame->insn))((void) ((i < (sizeof (tramp_frame->insn) / sizeof ((tramp_frame ->insn)[0]))) ? 0 : (internal_error ("/usr/src/gnu/usr.bin/binutils/gdb/tramp-frame.c" , 162, "%s: Assertion `%s' failed.", __PRETTY_FUNCTION__, "i < ARRAY_SIZE (tramp_frame->insn)" ), 0))); |
| 163 | gdb_assert (tramp_frame->insn_size <= sizeof (tramp_frame->insn[0].bytes))((void) ((tramp_frame->insn_size <= sizeof (tramp_frame ->insn[0].bytes)) ? 0 : (internal_error ("/usr/src/gnu/usr.bin/binutils/gdb/tramp-frame.c" , 163, "%s: Assertion `%s' failed.", __PRETTY_FUNCTION__, "tramp_frame->insn_size <= sizeof (tramp_frame->insn[0].bytes)" ), 0))); |
| 164 | |
| 165 | data = GDBARCH_OBSTACK_ZALLOC (gdbarch, struct frame_data)((struct frame_data *) gdbarch_obstack_zalloc ((gdbarch), sizeof (struct frame_data))); |
| 166 | unwinder = GDBARCH_OBSTACK_ZALLOC (gdbarch, struct frame_unwind)((struct frame_unwind *) gdbarch_obstack_zalloc ((gdbarch), sizeof (struct frame_unwind))); |
| 167 | |
| 168 | data->tramp_frame = tramp_frame; |
| 169 | unwinder->type = SIGTRAMP_FRAME; |
| 170 | unwinder->unwind_data = data; |
| 171 | unwinder->sniffer = tramp_frame_sniffer; |
| 172 | unwinder->this_id = tramp_frame_this_id; |
| 173 | unwinder->prev_register = tramp_frame_prev_register; |
| 174 | frame_unwind_prepend_unwinder (gdbarch, unwinder); |
| 175 | } |