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d2259dd3 AC |
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" | |
1196bfda | 31 | #include "gdb_assert.h" |
d2259dd3 AC |
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); | |
50 | struct tramp_frame_cache *tramp_cache = (*this_cache); | |
51 | if (tramp_cache->trad_cache == NULL) | |
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 (CORE_ADDR pc, const struct tramp_frame *tramp) | |
89 | { | |
90 | int ti; | |
91 | /* Search through the trampoline for one that matches the | |
92 | instruction sequence around PC. */ | |
1196bfda | 93 | for (ti = 0; tramp->insn[ti] != TRAMP_SENTINEL_INSN; ti++) |
d2259dd3 AC |
94 | { |
95 | CORE_ADDR func = pc - tramp->insn_size * ti; | |
96 | int i; | |
97 | for (i = 0; 1; i++) | |
98 | { | |
1196bfda AC |
99 | bfd_byte buf[sizeof (tramp->insn[0])]; |
100 | ULONGEST insn; | |
101 | if (tramp->insn[i] == TRAMP_SENTINEL_INSN) | |
d2259dd3 AC |
102 | return func; |
103 | if (target_read_memory (func + i * tramp->insn_size, buf, | |
104 | tramp->insn_size) != 0) | |
105 | break; | |
106 | insn = extract_unsigned_integer (buf, tramp->insn_size); | |
107 | if (tramp->insn[i] != insn) | |
108 | break; | |
109 | } | |
110 | } | |
111 | /* Trampoline doesn't match. */ | |
112 | return 0; | |
113 | } | |
114 | ||
115 | static int | |
116 | tramp_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 | char *name; | |
124 | struct tramp_frame_cache *tramp_cache; | |
125 | ||
126 | /* If the function has a valid symbol name, it isn't a | |
127 | trampoline. */ | |
128 | find_pc_partial_function (pc, &name, NULL, NULL); | |
129 | if (name != NULL) | |
130 | return 0; | |
131 | /* If the function lives in a valid section (even without a starting | |
132 | point) it isn't a trampoline. */ | |
133 | if (find_pc_section (pc) != NULL) | |
134 | return 0; | |
135 | /* Finally, check that the trampoline matches at PC. */ | |
136 | func = tramp_frame_start (pc, tramp); | |
137 | if (func == 0) | |
138 | return 0; | |
139 | tramp_cache = FRAME_OBSTACK_ZALLOC (struct tramp_frame_cache); | |
140 | tramp_cache->func = func; | |
141 | tramp_cache->tramp_frame = tramp; | |
142 | (*this_cache) = tramp_cache; | |
143 | return 1; | |
144 | } | |
145 | ||
146 | void | |
147 | tramp_frame_append (struct gdbarch *gdbarch, | |
148 | const struct tramp_frame *tramp_frame) | |
149 | { | |
150 | struct frame_data *data; | |
151 | struct frame_unwind *unwinder; | |
1196bfda AC |
152 | int i; |
153 | ||
154 | /* Check that the instruction sequence contains a sentinel. */ | |
155 | for (i = 0; i < ARRAY_SIZE (tramp_frame->insn); i++) | |
156 | { | |
157 | if (tramp_frame->insn[i] == TRAMP_SENTINEL_INSN) | |
158 | break; | |
159 | } | |
160 | gdb_assert (i < ARRAY_SIZE (tramp_frame->insn)); | |
161 | gdb_assert (tramp_frame->insn_size <= sizeof (tramp_frame->insn[0])); | |
d2259dd3 AC |
162 | |
163 | data = GDBARCH_OBSTACK_ZALLOC (gdbarch, struct frame_data); | |
164 | unwinder = GDBARCH_OBSTACK_ZALLOC (gdbarch, struct frame_unwind); | |
165 | ||
166 | data->tramp_frame = tramp_frame; | |
167 | unwinder->type = SIGTRAMP_FRAME; | |
168 | unwinder->unwind_data = data; | |
169 | unwinder->sniffer = tramp_frame_sniffer; | |
170 | unwinder->this_id = tramp_frame_this_id; | |
171 | unwinder->prev_register = tramp_frame_prev_register; | |
172 | frame_unwind_register_unwinder (gdbarch, unwinder); | |
173 | } |