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494cca16 AC |
1 | /* Definitions for frame unwinder, for GDB, the GNU debugger. |
2 | ||
b811d2c2 | 3 | Copyright (C) 2003-2020 Free Software Foundation, Inc. |
494cca16 AC |
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 | |
a9762ec7 | 9 | the Free Software Foundation; either version 3 of the License, or |
494cca16 AC |
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 | |
a9762ec7 | 18 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
494cca16 AC |
19 | |
20 | #include "defs.h" | |
d55e5aa6 | 21 | #include "frame.h" |
4de283e4 TT |
22 | #include "frame-unwind.h" |
23 | #include "dummy-frame.h" | |
edb3359d | 24 | #include "inline-frame.h" |
4de283e4 | 25 | #include "value.h" |
669fac23 | 26 | #include "regcache.h" |
4de283e4 | 27 | #include "gdb_obstack.h" |
ea001bdc | 28 | #include "target.h" |
0d12e84c | 29 | #include "gdbarch.h" |
1009d92f | 30 | #include "dwarf2/frame-tailcall.h" |
494cca16 AC |
31 | |
32 | static struct gdbarch_data *frame_unwind_data; | |
33 | ||
41fe5eb3 | 34 | struct frame_unwind_table_entry |
494cca16 | 35 | { |
82417da5 | 36 | const struct frame_unwind *unwinder; |
41fe5eb3 | 37 | struct frame_unwind_table_entry *next; |
494cca16 AC |
38 | }; |
39 | ||
41fe5eb3 | 40 | struct frame_unwind_table |
494cca16 | 41 | { |
fb2be677 AC |
42 | struct frame_unwind_table_entry *list; |
43 | /* The head of the OSABI part of the search list. */ | |
44 | struct frame_unwind_table_entry **osabi_head; | |
41fe5eb3 | 45 | }; |
494cca16 | 46 | |
1009d92f TT |
47 | /* A helper function to add an unwinder to a list. LINK says where to |
48 | install the new unwinder. The new link is returned. */ | |
49 | ||
50 | static struct frame_unwind_table_entry ** | |
51 | add_unwinder (struct obstack *obstack, const struct frame_unwind *unwinder, | |
52 | struct frame_unwind_table_entry **link) | |
53 | { | |
54 | *link = OBSTACK_ZALLOC (obstack, struct frame_unwind_table_entry); | |
55 | (*link)->unwinder = unwinder; | |
56 | return &(*link)->next; | |
57 | } | |
58 | ||
494cca16 | 59 | static void * |
41fe5eb3 | 60 | frame_unwind_init (struct obstack *obstack) |
494cca16 | 61 | { |
41fe5eb3 AC |
62 | struct frame_unwind_table *table |
63 | = OBSTACK_ZALLOC (obstack, struct frame_unwind_table); | |
bb9bcb69 | 64 | |
fb2be677 AC |
65 | /* Start the table out with a few default sniffers. OSABI code |
66 | can't override this. */ | |
1009d92f TT |
67 | struct frame_unwind_table_entry **link = &table->list; |
68 | ||
69 | link = add_unwinder (obstack, &dummy_frame_unwind, link); | |
70 | /* The DWARF tailcall sniffer must come before the inline sniffer. | |
71 | Otherwise, we can end up in a situation where a DWARF frame finds | |
72 | tailcall information, but then the inline sniffer claims a frame | |
73 | before the tailcall sniffer, resulting in confusion. This is | |
74 | safe to do always because the tailcall sniffer can only ever be | |
75 | activated if the newer frame was created using the DWARF | |
76 | unwinder, and it also found tailcall information. */ | |
77 | link = add_unwinder (obstack, &dwarf2_tailcall_frame_unwind, link); | |
78 | link = add_unwinder (obstack, &inline_frame_unwind, link); | |
79 | ||
fb2be677 | 80 | /* The insertion point for OSABI sniffers. */ |
1009d92f | 81 | table->osabi_head = link; |
494cca16 AC |
82 | return table; |
83 | } | |
84 | ||
82417da5 | 85 | void |
fb2be677 | 86 | frame_unwind_prepend_unwinder (struct gdbarch *gdbarch, |
82417da5 AC |
87 | const struct frame_unwind *unwinder) |
88 | { | |
9a3c8263 SM |
89 | struct frame_unwind_table *table |
90 | = (struct frame_unwind_table *) gdbarch_data (gdbarch, frame_unwind_data); | |
fb2be677 AC |
91 | struct frame_unwind_table_entry *entry; |
92 | ||
93 | /* Insert the new entry at the start of the list. */ | |
94 | entry = GDBARCH_OBSTACK_ZALLOC (gdbarch, struct frame_unwind_table_entry); | |
95 | entry->unwinder = unwinder; | |
96 | entry->next = (*table->osabi_head); | |
97 | (*table->osabi_head) = entry; | |
82417da5 AC |
98 | } |
99 | ||
669fac23 DJ |
100 | void |
101 | frame_unwind_append_unwinder (struct gdbarch *gdbarch, | |
102 | const struct frame_unwind *unwinder) | |
103 | { | |
9a3c8263 SM |
104 | struct frame_unwind_table *table |
105 | = (struct frame_unwind_table *) gdbarch_data (gdbarch, frame_unwind_data); | |
669fac23 DJ |
106 | struct frame_unwind_table_entry **ip; |
107 | ||
108 | /* Find the end of the list and insert the new entry there. */ | |
109 | for (ip = table->osabi_head; (*ip) != NULL; ip = &(*ip)->next); | |
110 | (*ip) = GDBARCH_OBSTACK_ZALLOC (gdbarch, struct frame_unwind_table_entry); | |
111 | (*ip)->unwinder = unwinder; | |
112 | } | |
113 | ||
ea001bdc MM |
114 | /* Call SNIFFER from UNWINDER. If it succeeded set UNWINDER for |
115 | THIS_FRAME and return 1. Otherwise the function keeps THIS_FRAME | |
116 | unchanged and returns 0. */ | |
117 | ||
118 | static int | |
119 | frame_unwind_try_unwinder (struct frame_info *this_frame, void **this_cache, | |
120 | const struct frame_unwind *unwinder) | |
121 | { | |
ea001bdc MM |
122 | int res = 0; |
123 | ||
30a9c02f | 124 | frame_prepare_for_sniffer (this_frame, unwinder); |
ea001bdc | 125 | |
a70b8144 | 126 | try |
ea001bdc MM |
127 | { |
128 | res = unwinder->sniffer (unwinder, this_frame, this_cache); | |
129 | } | |
230d2906 | 130 | catch (const gdb_exception &ex) |
ea001bdc | 131 | { |
be7d3cd5 YQ |
132 | /* Catch all exceptions, caused by either interrupt or error. |
133 | Reset *THIS_CACHE. */ | |
134 | *this_cache = NULL; | |
980548fd PA |
135 | frame_cleanup_after_sniffer (this_frame); |
136 | ||
7556d4a4 PA |
137 | if (ex.error == NOT_AVAILABLE_ERROR) |
138 | { | |
139 | /* This usually means that not even the PC is available, | |
140 | thus most unwinders aren't able to determine if they're | |
141 | the best fit. Keep trying. Fallback prologue unwinders | |
142 | should always accept the frame. */ | |
7556d4a4 PA |
143 | return 0; |
144 | } | |
eedc3f4f | 145 | throw; |
ea001bdc | 146 | } |
7556d4a4 PA |
147 | |
148 | if (res) | |
30a9c02f | 149 | return 1; |
ea001bdc MM |
150 | else |
151 | { | |
be7d3cd5 YQ |
152 | /* Don't set *THIS_CACHE to NULL here, because sniffer has to do |
153 | so. */ | |
30a9c02f | 154 | frame_cleanup_after_sniffer (this_frame); |
ea001bdc MM |
155 | return 0; |
156 | } | |
157 | gdb_assert_not_reached ("frame_unwind_try_unwinder"); | |
158 | } | |
159 | ||
9f9a8002 JK |
160 | /* Iterate through sniffers for THIS_FRAME frame until one returns with an |
161 | unwinder implementation. THIS_FRAME->UNWIND must be NULL, it will get set | |
162 | by this function. Possibly initialize THIS_CACHE. */ | |
163 | ||
164 | void | |
669fac23 | 165 | frame_unwind_find_by_frame (struct frame_info *this_frame, void **this_cache) |
e8a89fe2 | 166 | { |
669fac23 | 167 | struct gdbarch *gdbarch = get_frame_arch (this_frame); |
9a3c8263 SM |
168 | struct frame_unwind_table *table |
169 | = (struct frame_unwind_table *) gdbarch_data (gdbarch, frame_unwind_data); | |
41fe5eb3 | 170 | struct frame_unwind_table_entry *entry; |
ea001bdc MM |
171 | const struct frame_unwind *unwinder_from_target; |
172 | ||
173 | unwinder_from_target = target_get_unwinder (); | |
174 | if (unwinder_from_target != NULL | |
175 | && frame_unwind_try_unwinder (this_frame, this_cache, | |
176 | unwinder_from_target)) | |
177 | return; | |
178 | ||
179 | unwinder_from_target = target_get_tailcall_unwinder (); | |
180 | if (unwinder_from_target != NULL | |
181 | && frame_unwind_try_unwinder (this_frame, this_cache, | |
182 | unwinder_from_target)) | |
183 | return; | |
1c5465ac | 184 | |
fb2be677 | 185 | for (entry = table->list; entry != NULL; entry = entry->next) |
ea001bdc MM |
186 | if (frame_unwind_try_unwinder (this_frame, this_cache, entry->unwinder)) |
187 | return; | |
8fbca658 | 188 | |
e2e0b3e5 | 189 | internal_error (__FILE__, __LINE__, _("frame_unwind_find_by_frame failed")); |
494cca16 AC |
190 | } |
191 | ||
669fac23 DJ |
192 | /* A default frame sniffer which always accepts the frame. Used by |
193 | fallback prologue unwinders. */ | |
194 | ||
195 | int | |
196 | default_frame_sniffer (const struct frame_unwind *self, | |
197 | struct frame_info *this_frame, | |
198 | void **this_prologue_cache) | |
199 | { | |
200 | return 1; | |
201 | } | |
202 | ||
50fd528a | 203 | /* The default frame unwinder stop_reason callback. */ |
8fbca658 PA |
204 | |
205 | enum unwind_stop_reason | |
206 | default_frame_unwind_stop_reason (struct frame_info *this_frame, | |
207 | void **this_cache) | |
208 | { | |
50fd528a PA |
209 | struct frame_id this_id = get_frame_id (this_frame); |
210 | ||
211 | if (frame_id_eq (this_id, outer_frame_id)) | |
212 | return UNWIND_OUTERMOST; | |
213 | else | |
214 | return UNWIND_NO_REASON; | |
8fbca658 PA |
215 | } |
216 | ||
8bcb5208 AB |
217 | /* See frame-unwind.h. */ |
218 | ||
219 | CORE_ADDR | |
220 | default_unwind_pc (struct gdbarch *gdbarch, struct frame_info *next_frame) | |
221 | { | |
222 | int pc_regnum = gdbarch_pc_regnum (gdbarch); | |
223 | CORE_ADDR pc = frame_unwind_register_unsigned (next_frame, pc_regnum); | |
224 | pc = gdbarch_addr_bits_remove (gdbarch, pc); | |
225 | return pc; | |
226 | } | |
227 | ||
228 | /* See frame-unwind.h. */ | |
229 | ||
230 | CORE_ADDR | |
231 | default_unwind_sp (struct gdbarch *gdbarch, struct frame_info *next_frame) | |
232 | { | |
233 | int sp_regnum = gdbarch_sp_regnum (gdbarch); | |
234 | return frame_unwind_register_unsigned (next_frame, sp_regnum); | |
235 | } | |
236 | ||
669fac23 DJ |
237 | /* Helper functions for value-based register unwinding. These return |
238 | a (possibly lazy) value of the appropriate type. */ | |
239 | ||
240 | /* Return a value which indicates that FRAME did not save REGNUM. */ | |
241 | ||
242 | struct value * | |
243 | frame_unwind_got_optimized (struct frame_info *frame, int regnum) | |
244 | { | |
908fa2aa PA |
245 | struct gdbarch *gdbarch = frame_unwind_arch (frame); |
246 | struct type *type = register_type (gdbarch, regnum); | |
6bd273ae | 247 | struct value *val; |
669fac23 | 248 | |
908fa2aa PA |
249 | /* Return an lval_register value, so that we print it as |
250 | "<not saved>". */ | |
251 | val = allocate_value_lazy (type); | |
6bd273ae | 252 | set_value_lazy (val, 0); |
9a0dc9e3 | 253 | mark_value_bytes_optimized_out (val, 0, TYPE_LENGTH (type)); |
908fa2aa PA |
254 | VALUE_LVAL (val) = lval_register; |
255 | VALUE_REGNUM (val) = regnum; | |
41b56feb KB |
256 | VALUE_NEXT_FRAME_ID (val) |
257 | = get_frame_id (get_next_frame_sentinel_okay (frame)); | |
6bd273ae | 258 | return val; |
669fac23 DJ |
259 | } |
260 | ||
261 | /* Return a value which indicates that FRAME copied REGNUM into | |
262 | register NEW_REGNUM. */ | |
263 | ||
264 | struct value * | |
3e43a32a MS |
265 | frame_unwind_got_register (struct frame_info *frame, |
266 | int regnum, int new_regnum) | |
669fac23 DJ |
267 | { |
268 | return value_of_register_lazy (frame, new_regnum); | |
269 | } | |
270 | ||
271 | /* Return a value which indicates that FRAME saved REGNUM in memory at | |
272 | ADDR. */ | |
273 | ||
274 | struct value * | |
275 | frame_unwind_got_memory (struct frame_info *frame, int regnum, CORE_ADDR addr) | |
276 | { | |
36f15f55 | 277 | struct gdbarch *gdbarch = frame_unwind_arch (frame); |
4e5d721f | 278 | struct value *v = value_at_lazy (register_type (gdbarch, regnum), addr); |
669fac23 | 279 | |
4e5d721f DE |
280 | set_value_stack (v, 1); |
281 | return v; | |
669fac23 DJ |
282 | } |
283 | ||
284 | /* Return a value which indicates that FRAME's saved version of | |
285 | REGNUM has a known constant (computed) value of VAL. */ | |
286 | ||
287 | struct value * | |
288 | frame_unwind_got_constant (struct frame_info *frame, int regnum, | |
289 | ULONGEST val) | |
290 | { | |
36f15f55 | 291 | struct gdbarch *gdbarch = frame_unwind_arch (frame); |
e17a4113 | 292 | enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); |
669fac23 DJ |
293 | struct value *reg_val; |
294 | ||
295 | reg_val = value_zero (register_type (gdbarch, regnum), not_lval); | |
296 | store_unsigned_integer (value_contents_writeable (reg_val), | |
e17a4113 | 297 | register_size (gdbarch, regnum), byte_order, val); |
669fac23 DJ |
298 | return reg_val; |
299 | } | |
300 | ||
15c1e57f JB |
301 | struct value * |
302 | frame_unwind_got_bytes (struct frame_info *frame, int regnum, gdb_byte *buf) | |
303 | { | |
36f15f55 | 304 | struct gdbarch *gdbarch = frame_unwind_arch (frame); |
15c1e57f JB |
305 | struct value *reg_val; |
306 | ||
307 | reg_val = value_zero (register_type (gdbarch, regnum), not_lval); | |
308 | memcpy (value_contents_raw (reg_val), buf, register_size (gdbarch, regnum)); | |
309 | return reg_val; | |
310 | } | |
311 | ||
669fac23 DJ |
312 | /* Return a value which indicates that FRAME's saved version of REGNUM |
313 | has a known constant (computed) value of ADDR. Convert the | |
314 | CORE_ADDR to a target address if necessary. */ | |
315 | ||
316 | struct value * | |
317 | frame_unwind_got_address (struct frame_info *frame, int regnum, | |
318 | CORE_ADDR addr) | |
319 | { | |
36f15f55 | 320 | struct gdbarch *gdbarch = frame_unwind_arch (frame); |
669fac23 DJ |
321 | struct value *reg_val; |
322 | ||
323 | reg_val = value_zero (register_type (gdbarch, regnum), not_lval); | |
324 | pack_long (value_contents_writeable (reg_val), | |
325 | register_type (gdbarch, regnum), addr); | |
326 | return reg_val; | |
327 | } | |
328 | ||
6c265988 | 329 | void _initialize_frame_unwind (); |
494cca16 | 330 | void |
6c265988 | 331 | _initialize_frame_unwind () |
494cca16 | 332 | { |
41fe5eb3 | 333 | frame_unwind_data = gdbarch_data_register_pre_init (frame_unwind_init); |
494cca16 | 334 | } |