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b811d2c2 | 1 | /* Copyright (C) 2009-2020 Free Software Foundation, Inc. |
2838cc1d SD |
2 | |
3 | This file is part of GDB. | |
4 | ||
5 | This program is free software; you can redistribute it and/or modify | |
6 | it under the terms of the GNU General Public License as published by | |
7 | the Free Software Foundation; either version 3 of the License, or | |
8 | (at your option) any later version. | |
9 | ||
10 | This program is distributed in the hope that it will be useful, | |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | GNU General Public License for more details. | |
14 | ||
15 | You should have received a copy of the GNU General Public License | |
16 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ | |
17 | ||
18 | #include <stdint.h> | |
19 | #include <stdio.h> | |
20 | #include <stdlib.h> | |
21 | #include <string.h> | |
22 | ||
23 | #include JIT_READER_H /* Please see jit-reader.exp for an explanation. */ | |
922a7c7c | 24 | #include "jit-reader-host.h" |
2838cc1d SD |
25 | |
26 | GDB_DECLARE_GPL_COMPATIBLE_READER; | |
27 | ||
28 | enum register_mapping | |
29 | { | |
30 | AMD64_RA = 16, | |
20aa2c60 | 31 | AMD64_RBP = 6, |
2838cc1d SD |
32 | AMD64_RSP = 7, |
33 | }; | |
34 | ||
35 | struct reader_state | |
36 | { | |
d043f8c8 SM |
37 | struct { |
38 | uintptr_t begin; | |
39 | uintptr_t end; | |
40 | } func_stack_mangle; | |
2838cc1d SD |
41 | }; |
42 | ||
43 | static enum gdb_status | |
44 | read_debug_info (struct gdb_reader_funcs *self, | |
45 | struct gdb_symbol_callbacks *cbs, | |
46 | void *memory, long memory_sz) | |
47 | { | |
48 | struct jithost_abi *symfile = memory; | |
49 | struct gdb_object *object = cbs->object_open (cbs); | |
50 | struct gdb_symtab *symtab = cbs->symtab_open (cbs, object, ""); | |
d043f8c8 | 51 | |
20aa2c60 PA |
52 | struct reader_state *state = (struct reader_state *) self->priv_data; |
53 | ||
d043f8c8 SM |
54 | /* Record the stack mangle function's range, for the unwinder. */ |
55 | state->func_stack_mangle.begin | |
56 | = (uintptr_t) symfile->function_stack_mangle.begin; | |
57 | state->func_stack_mangle.end | |
58 | = (uintptr_t) symfile->function_stack_mangle.end; | |
59 | ||
60 | cbs->block_open (cbs, symtab, NULL, | |
61 | (GDB_CORE_ADDR) symfile->function_stack_mangle.begin, | |
62 | (GDB_CORE_ADDR) symfile->function_stack_mangle.end, | |
63 | "jit_function_stack_mangle"); | |
2838cc1d | 64 | |
d043f8c8 SM |
65 | cbs->block_open (cbs, symtab, NULL, |
66 | (GDB_CORE_ADDR) symfile->function_add.begin, | |
67 | (GDB_CORE_ADDR) symfile->function_add.end, | |
68 | "jit_function_add"); | |
2838cc1d SD |
69 | |
70 | cbs->symtab_close (cbs, symtab); | |
71 | cbs->object_close (cbs, object); | |
72 | return GDB_SUCCESS; | |
73 | } | |
74 | ||
75 | static void | |
76 | free_reg_value (struct gdb_reg_value *value) | |
77 | { | |
78 | free (value); | |
79 | } | |
80 | ||
81 | static void | |
82 | write_register (struct gdb_unwind_callbacks *callbacks, int dw_reg, | |
83 | uintptr_t value) | |
84 | { | |
85 | const int size = sizeof (uintptr_t); | |
86 | struct gdb_reg_value *reg_val = | |
87 | malloc (sizeof (struct gdb_reg_value) + size - 1); | |
88 | reg_val->defined = 1; | |
89 | reg_val->free = free_reg_value; | |
90 | ||
91 | memcpy (reg_val->value, &value, size); | |
92 | callbacks->reg_set (callbacks, dw_reg, reg_val); | |
93 | } | |
94 | ||
95 | static int | |
96 | read_register (struct gdb_unwind_callbacks *callbacks, int dw_reg, | |
97 | uintptr_t *value) | |
98 | { | |
99 | const int size = sizeof (uintptr_t); | |
100 | struct gdb_reg_value *reg_val = callbacks->reg_get (callbacks, dw_reg); | |
101 | if (reg_val->size != size || !reg_val->defined) | |
102 | { | |
103 | reg_val->free (reg_val); | |
104 | return 0; | |
105 | } | |
106 | memcpy (value, reg_val->value, size); | |
107 | reg_val->free (reg_val); | |
108 | return 1; | |
109 | } | |
110 | ||
20aa2c60 PA |
111 | /* Read the stack pointer into *VALUE. IP is the address the inferior |
112 | is currently stopped at. Takes care of demangling the stack | |
113 | pointer if necessary. */ | |
114 | ||
115 | static int | |
116 | read_sp (struct gdb_reader_funcs *self, struct gdb_unwind_callbacks *cbs, | |
117 | uintptr_t ip, uintptr_t *value) | |
118 | { | |
119 | struct reader_state *state = (struct reader_state *) self->priv_data; | |
120 | uintptr_t sp; | |
121 | ||
122 | if (!read_register (cbs, AMD64_RSP, &sp)) | |
123 | return GDB_FAIL; | |
124 | ||
125 | /* If stopped at the instruction after the "xor $-1, %rsp", demangle | |
126 | the stack pointer back. */ | |
d043f8c8 | 127 | if (ip == state->func_stack_mangle.begin + 5) |
20aa2c60 PA |
128 | sp ^= (uintptr_t) -1; |
129 | ||
130 | *value = sp; | |
131 | return GDB_SUCCESS; | |
132 | } | |
133 | ||
2838cc1d SD |
134 | static enum gdb_status |
135 | unwind_frame (struct gdb_reader_funcs *self, struct gdb_unwind_callbacks *cbs) | |
136 | { | |
137 | const int word_size = sizeof (uintptr_t); | |
20aa2c60 PA |
138 | uintptr_t prev_sp, this_sp; |
139 | uintptr_t prev_ip, this_ip; | |
140 | uintptr_t prev_bp, this_bp; | |
2838cc1d SD |
141 | struct reader_state *state = (struct reader_state *) self->priv_data; |
142 | ||
143 | if (!read_register (cbs, AMD64_RA, &this_ip)) | |
144 | return GDB_FAIL; | |
145 | ||
d043f8c8 SM |
146 | if (this_ip >= state->func_stack_mangle.end |
147 | || this_ip < state->func_stack_mangle.begin) | |
2838cc1d SD |
148 | return GDB_FAIL; |
149 | ||
20aa2c60 PA |
150 | /* Unwind RBP in order to make the unwinder that tries to unwind |
151 | from the just-unwound frame happy. */ | |
152 | if (!read_register (cbs, AMD64_RBP, &this_bp)) | |
2838cc1d | 153 | return GDB_FAIL; |
20aa2c60 PA |
154 | /* RBP is unmodified. */ |
155 | prev_bp = this_bp; | |
2838cc1d | 156 | |
20aa2c60 PA |
157 | /* Fetch the demangled stack pointer. */ |
158 | if (!read_sp (self, cbs, this_ip, &this_sp)) | |
2838cc1d SD |
159 | return GDB_FAIL; |
160 | ||
20aa2c60 PA |
161 | /* The return address is saved on the stack. */ |
162 | if (cbs->target_read (this_sp, &prev_ip, word_size) == GDB_FAIL) | |
163 | return GDB_FAIL; | |
2838cc1d | 164 | prev_sp = this_sp + word_size; |
20aa2c60 | 165 | |
2838cc1d SD |
166 | write_register (cbs, AMD64_RA, prev_ip); |
167 | write_register (cbs, AMD64_RSP, prev_sp); | |
20aa2c60 | 168 | write_register (cbs, AMD64_RBP, prev_bp); |
2838cc1d SD |
169 | return GDB_SUCCESS; |
170 | } | |
171 | ||
172 | static struct gdb_frame_id | |
173 | get_frame_id (struct gdb_reader_funcs *self, struct gdb_unwind_callbacks *cbs) | |
174 | { | |
175 | struct reader_state *state = (struct reader_state *) self->priv_data; | |
176 | struct gdb_frame_id frame_id; | |
20aa2c60 | 177 | uintptr_t ip; |
2838cc1d | 178 | uintptr_t sp; |
20aa2c60 PA |
179 | |
180 | read_register (cbs, AMD64_RA, &ip); | |
181 | read_sp (self, cbs, ip, &sp); | |
2838cc1d | 182 | |
d043f8c8 | 183 | frame_id.code_address = (GDB_CORE_ADDR) state->func_stack_mangle.begin; |
2838cc1d SD |
184 | frame_id.stack_address = (GDB_CORE_ADDR) sp; |
185 | ||
186 | return frame_id; | |
187 | } | |
188 | ||
189 | static void | |
190 | destroy_reader (struct gdb_reader_funcs *self) | |
191 | { | |
192 | free (self->priv_data); | |
193 | free (self); | |
194 | } | |
195 | ||
196 | struct gdb_reader_funcs * | |
197 | gdb_init_reader (void) | |
198 | { | |
20aa2c60 | 199 | struct reader_state *state = calloc (1, sizeof (struct reader_state)); |
2838cc1d SD |
200 | struct gdb_reader_funcs *reader_funcs = |
201 | malloc (sizeof (struct gdb_reader_funcs)); | |
202 | ||
203 | reader_funcs->reader_version = GDB_READER_INTERFACE_VERSION; | |
204 | reader_funcs->priv_data = state; | |
205 | reader_funcs->read = read_debug_info; | |
206 | reader_funcs->unwind = unwind_frame; | |
207 | reader_funcs->get_frame_id = get_frame_id; | |
208 | reader_funcs->destroy = destroy_reader; | |
209 | ||
210 | return reader_funcs; | |
211 | } |