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494cca16 AC |
1 | /* Definitions for frame unwinder, for GDB, the GNU debugger. |
2 | ||
3666a048 | 3 | Copyright (C) 2003-2021 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, | |
dda83cd7 | 120 | const struct frame_unwind *unwinder) |
ea001bdc | 121 | { |
ea001bdc MM |
122 | int res = 0; |
123 | ||
e7bc9db8 PA |
124 | unsigned int entry_generation = get_frame_cache_generation (); |
125 | ||
30a9c02f | 126 | frame_prepare_for_sniffer (this_frame, unwinder); |
ea001bdc | 127 | |
a70b8144 | 128 | try |
ea001bdc | 129 | { |
a154d838 | 130 | frame_debug_printf ("trying unwinder \"%s\"", unwinder->name); |
ea001bdc MM |
131 | res = unwinder->sniffer (unwinder, this_frame, this_cache); |
132 | } | |
230d2906 | 133 | catch (const gdb_exception &ex) |
ea001bdc | 134 | { |
a154d838 SM |
135 | frame_debug_printf ("caught exception: %s", ex.message->c_str ()); |
136 | ||
be7d3cd5 | 137 | /* Catch all exceptions, caused by either interrupt or error. |
e7bc9db8 PA |
138 | Reset *THIS_CACHE, unless something reinitialized the frame |
139 | cache meanwhile, in which case THIS_FRAME/THIS_CACHE are now | |
140 | dangling. */ | |
141 | if (get_frame_cache_generation () == entry_generation) | |
142 | { | |
143 | *this_cache = NULL; | |
144 | frame_cleanup_after_sniffer (this_frame); | |
145 | } | |
980548fd | 146 | |
7556d4a4 PA |
147 | if (ex.error == NOT_AVAILABLE_ERROR) |
148 | { | |
149 | /* This usually means that not even the PC is available, | |
150 | thus most unwinders aren't able to determine if they're | |
151 | the best fit. Keep trying. Fallback prologue unwinders | |
152 | should always accept the frame. */ | |
7556d4a4 PA |
153 | return 0; |
154 | } | |
eedc3f4f | 155 | throw; |
ea001bdc | 156 | } |
7556d4a4 PA |
157 | |
158 | if (res) | |
a154d838 SM |
159 | { |
160 | frame_debug_printf ("yes"); | |
161 | return 1; | |
162 | } | |
ea001bdc MM |
163 | else |
164 | { | |
a154d838 | 165 | frame_debug_printf ("no"); |
be7d3cd5 YQ |
166 | /* Don't set *THIS_CACHE to NULL here, because sniffer has to do |
167 | so. */ | |
30a9c02f | 168 | frame_cleanup_after_sniffer (this_frame); |
ea001bdc MM |
169 | return 0; |
170 | } | |
171 | gdb_assert_not_reached ("frame_unwind_try_unwinder"); | |
172 | } | |
173 | ||
9f9a8002 JK |
174 | /* Iterate through sniffers for THIS_FRAME frame until one returns with an |
175 | unwinder implementation. THIS_FRAME->UNWIND must be NULL, it will get set | |
176 | by this function. Possibly initialize THIS_CACHE. */ | |
177 | ||
178 | void | |
669fac23 | 179 | frame_unwind_find_by_frame (struct frame_info *this_frame, void **this_cache) |
e8a89fe2 | 180 | { |
a154d838 SM |
181 | frame_debug_printf ("this_frame=%d", frame_relative_level (this_frame)); |
182 | ||
669fac23 | 183 | struct gdbarch *gdbarch = get_frame_arch (this_frame); |
9a3c8263 SM |
184 | struct frame_unwind_table *table |
185 | = (struct frame_unwind_table *) gdbarch_data (gdbarch, frame_unwind_data); | |
41fe5eb3 | 186 | struct frame_unwind_table_entry *entry; |
ea001bdc MM |
187 | const struct frame_unwind *unwinder_from_target; |
188 | ||
189 | unwinder_from_target = target_get_unwinder (); | |
190 | if (unwinder_from_target != NULL | |
191 | && frame_unwind_try_unwinder (this_frame, this_cache, | |
dda83cd7 | 192 | unwinder_from_target)) |
ea001bdc MM |
193 | return; |
194 | ||
195 | unwinder_from_target = target_get_tailcall_unwinder (); | |
196 | if (unwinder_from_target != NULL | |
197 | && frame_unwind_try_unwinder (this_frame, this_cache, | |
dda83cd7 | 198 | unwinder_from_target)) |
ea001bdc | 199 | return; |
1c5465ac | 200 | |
fb2be677 | 201 | for (entry = table->list; entry != NULL; entry = entry->next) |
ea001bdc MM |
202 | if (frame_unwind_try_unwinder (this_frame, this_cache, entry->unwinder)) |
203 | return; | |
8fbca658 | 204 | |
e2e0b3e5 | 205 | internal_error (__FILE__, __LINE__, _("frame_unwind_find_by_frame failed")); |
494cca16 AC |
206 | } |
207 | ||
669fac23 DJ |
208 | /* A default frame sniffer which always accepts the frame. Used by |
209 | fallback prologue unwinders. */ | |
210 | ||
211 | int | |
212 | default_frame_sniffer (const struct frame_unwind *self, | |
213 | struct frame_info *this_frame, | |
214 | void **this_prologue_cache) | |
215 | { | |
216 | return 1; | |
217 | } | |
218 | ||
50fd528a | 219 | /* The default frame unwinder stop_reason callback. */ |
8fbca658 PA |
220 | |
221 | enum unwind_stop_reason | |
222 | default_frame_unwind_stop_reason (struct frame_info *this_frame, | |
223 | void **this_cache) | |
224 | { | |
50fd528a PA |
225 | struct frame_id this_id = get_frame_id (this_frame); |
226 | ||
227 | if (frame_id_eq (this_id, outer_frame_id)) | |
228 | return UNWIND_OUTERMOST; | |
229 | else | |
230 | return UNWIND_NO_REASON; | |
8fbca658 PA |
231 | } |
232 | ||
8bcb5208 AB |
233 | /* See frame-unwind.h. */ |
234 | ||
235 | CORE_ADDR | |
236 | default_unwind_pc (struct gdbarch *gdbarch, struct frame_info *next_frame) | |
237 | { | |
238 | int pc_regnum = gdbarch_pc_regnum (gdbarch); | |
239 | CORE_ADDR pc = frame_unwind_register_unsigned (next_frame, pc_regnum); | |
240 | pc = gdbarch_addr_bits_remove (gdbarch, pc); | |
241 | return pc; | |
242 | } | |
243 | ||
244 | /* See frame-unwind.h. */ | |
245 | ||
246 | CORE_ADDR | |
247 | default_unwind_sp (struct gdbarch *gdbarch, struct frame_info *next_frame) | |
248 | { | |
249 | int sp_regnum = gdbarch_sp_regnum (gdbarch); | |
250 | return frame_unwind_register_unsigned (next_frame, sp_regnum); | |
251 | } | |
252 | ||
669fac23 DJ |
253 | /* Helper functions for value-based register unwinding. These return |
254 | a (possibly lazy) value of the appropriate type. */ | |
255 | ||
256 | /* Return a value which indicates that FRAME did not save REGNUM. */ | |
257 | ||
258 | struct value * | |
259 | frame_unwind_got_optimized (struct frame_info *frame, int regnum) | |
260 | { | |
908fa2aa PA |
261 | struct gdbarch *gdbarch = frame_unwind_arch (frame); |
262 | struct type *type = register_type (gdbarch, regnum); | |
8efaf6b3 SM |
263 | |
264 | return allocate_optimized_out_value (type); | |
669fac23 DJ |
265 | } |
266 | ||
267 | /* Return a value which indicates that FRAME copied REGNUM into | |
268 | register NEW_REGNUM. */ | |
269 | ||
270 | struct value * | |
3e43a32a MS |
271 | frame_unwind_got_register (struct frame_info *frame, |
272 | int regnum, int new_regnum) | |
669fac23 DJ |
273 | { |
274 | return value_of_register_lazy (frame, new_regnum); | |
275 | } | |
276 | ||
277 | /* Return a value which indicates that FRAME saved REGNUM in memory at | |
278 | ADDR. */ | |
279 | ||
280 | struct value * | |
281 | frame_unwind_got_memory (struct frame_info *frame, int regnum, CORE_ADDR addr) | |
282 | { | |
36f15f55 | 283 | struct gdbarch *gdbarch = frame_unwind_arch (frame); |
4e5d721f | 284 | struct value *v = value_at_lazy (register_type (gdbarch, regnum), addr); |
669fac23 | 285 | |
4e5d721f DE |
286 | set_value_stack (v, 1); |
287 | return v; | |
669fac23 DJ |
288 | } |
289 | ||
290 | /* Return a value which indicates that FRAME's saved version of | |
291 | REGNUM has a known constant (computed) value of VAL. */ | |
292 | ||
293 | struct value * | |
294 | frame_unwind_got_constant (struct frame_info *frame, int regnum, | |
295 | ULONGEST val) | |
296 | { | |
36f15f55 | 297 | struct gdbarch *gdbarch = frame_unwind_arch (frame); |
e17a4113 | 298 | enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); |
669fac23 DJ |
299 | struct value *reg_val; |
300 | ||
301 | reg_val = value_zero (register_type (gdbarch, regnum), not_lval); | |
302 | store_unsigned_integer (value_contents_writeable (reg_val), | |
e17a4113 | 303 | register_size (gdbarch, regnum), byte_order, val); |
669fac23 DJ |
304 | return reg_val; |
305 | } | |
306 | ||
15c1e57f | 307 | struct value * |
098caef4 | 308 | frame_unwind_got_bytes (struct frame_info *frame, int regnum, const gdb_byte *buf) |
15c1e57f | 309 | { |
36f15f55 | 310 | struct gdbarch *gdbarch = frame_unwind_arch (frame); |
15c1e57f JB |
311 | struct value *reg_val; |
312 | ||
313 | reg_val = value_zero (register_type (gdbarch, regnum), not_lval); | |
314 | memcpy (value_contents_raw (reg_val), buf, register_size (gdbarch, regnum)); | |
315 | return reg_val; | |
316 | } | |
317 | ||
669fac23 DJ |
318 | /* Return a value which indicates that FRAME's saved version of REGNUM |
319 | has a known constant (computed) value of ADDR. Convert the | |
320 | CORE_ADDR to a target address if necessary. */ | |
321 | ||
322 | struct value * | |
323 | frame_unwind_got_address (struct frame_info *frame, int regnum, | |
324 | CORE_ADDR addr) | |
325 | { | |
36f15f55 | 326 | struct gdbarch *gdbarch = frame_unwind_arch (frame); |
669fac23 DJ |
327 | struct value *reg_val; |
328 | ||
329 | reg_val = value_zero (register_type (gdbarch, regnum), not_lval); | |
330 | pack_long (value_contents_writeable (reg_val), | |
331 | register_type (gdbarch, regnum), addr); | |
332 | return reg_val; | |
333 | } | |
334 | ||
6c265988 | 335 | void _initialize_frame_unwind (); |
494cca16 | 336 | void |
6c265988 | 337 | _initialize_frame_unwind () |
494cca16 | 338 | { |
41fe5eb3 | 339 | frame_unwind_data = gdbarch_data_register_pre_init (frame_unwind_init); |
494cca16 | 340 | } |