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0e5d83e3 JJ |
1 | /* Frame unwinder for frames using the libunwind library. |
2 | ||
6aba47ca | 3 | Copyright (C) 2003, 2004, 2006, 2007 Free Software Foundation, Inc. |
0e5d83e3 JJ |
4 | |
5 | Written by Jeff Johnston, contributed by Red Hat Inc. | |
6 | ||
7 | This file is part of GDB. | |
8 | ||
9 | This program is free software; you can redistribute it and/or modify | |
10 | it under the terms of the GNU General Public License as published by | |
11 | the Free Software Foundation; either version 2 of the License, or | |
12 | (at your option) any later version. | |
13 | ||
14 | This program is distributed in the hope that it will be useful, | |
15 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
16 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
17 | GNU General Public License for more details. | |
18 | ||
19 | You should have received a copy of the GNU General Public License | |
20 | along with this program; if not, write to the Free Software | |
197e01b6 EZ |
21 | Foundation, Inc., 51 Franklin Street, Fifth Floor, |
22 | Boston, MA 02110-1301, USA. */ | |
0e5d83e3 JJ |
23 | |
24 | #include "defs.h" | |
25 | ||
26 | #include "inferior.h" | |
27 | #include "frame.h" | |
28 | #include "frame-base.h" | |
29 | #include "frame-unwind.h" | |
30 | #include "gdbcore.h" | |
31 | #include "gdbtypes.h" | |
32 | #include "symtab.h" | |
33 | #include "objfiles.h" | |
34 | #include "regcache.h" | |
35 | ||
36 | #include <dlfcn.h> | |
37 | ||
38 | #include "gdb_assert.h" | |
39 | #include "gdb_string.h" | |
40 | ||
41 | #include "libunwind-frame.h" | |
42 | ||
43 | #include "complaints.h" | |
44 | ||
45 | static int libunwind_initialized; | |
46 | static struct gdbarch_data *libunwind_descr_handle; | |
47 | ||
0e5d83e3 JJ |
48 | /* Required function pointers from libunwind. */ |
49 | static int (*unw_get_reg_p) (unw_cursor_t *, unw_regnum_t, unw_word_t *); | |
50 | static int (*unw_get_fpreg_p) (unw_cursor_t *, unw_regnum_t, unw_fpreg_t *); | |
51 | static int (*unw_get_saveloc_p) (unw_cursor_t *, unw_regnum_t, unw_save_loc_t *); | |
c5a27d9c | 52 | static int (*unw_is_signal_frame_p) (unw_cursor_t *); |
0e5d83e3 JJ |
53 | static int (*unw_step_p) (unw_cursor_t *); |
54 | static int (*unw_init_remote_p) (unw_cursor_t *, unw_addr_space_t, void *); | |
55 | static unw_addr_space_t (*unw_create_addr_space_p) (unw_accessors_t *, int); | |
56 | static int (*unw_search_unwind_table_p) (unw_addr_space_t, unw_word_t, unw_dyn_info_t *, | |
57 | unw_proc_info_t *, int, void *); | |
503ff15d KB |
58 | static unw_word_t (*unw_find_dyn_list_p) (unw_addr_space_t, unw_dyn_info_t *, |
59 | void *); | |
0e5d83e3 JJ |
60 | |
61 | ||
62 | struct libunwind_frame_cache | |
63 | { | |
64 | CORE_ADDR base; | |
65 | CORE_ADDR func_addr; | |
66 | unw_cursor_t cursor; | |
67 | }; | |
68 | ||
69 | /* We need to qualify the function names with a platform-specific prefix to match | |
70 | the names used by the libunwind library. The UNW_OBJ macro is provided by the | |
71 | libunwind.h header file. */ | |
72 | #define STRINGIFY2(name) #name | |
73 | #define STRINGIFY(name) STRINGIFY2(name) | |
74 | ||
38e400fa | 75 | #ifndef LIBUNWIND_SO |
70f575cc JK |
76 | /* Use the stable ABI major version number. `libunwind-ia64.so' is a link time |
77 | only library, not a runtime one. */ | |
78 | #define LIBUNWIND_SO "libunwind-" STRINGIFY(UNW_TARGET) ".so.7" | |
38e400fa JJ |
79 | #endif |
80 | ||
0e5d83e3 JJ |
81 | static char *get_reg_name = STRINGIFY(UNW_OBJ(get_reg)); |
82 | static char *get_fpreg_name = STRINGIFY(UNW_OBJ(get_fpreg)); | |
83 | static char *get_saveloc_name = STRINGIFY(UNW_OBJ(get_save_loc)); | |
c5a27d9c | 84 | static char *is_signal_frame_name = STRINGIFY(UNW_OBJ(is_signal_frame)); |
0e5d83e3 JJ |
85 | static char *step_name = STRINGIFY(UNW_OBJ(step)); |
86 | static char *init_remote_name = STRINGIFY(UNW_OBJ(init_remote)); | |
87 | static char *create_addr_space_name = STRINGIFY(UNW_OBJ(create_addr_space)); | |
88 | static char *search_unwind_table_name = STRINGIFY(UNW_OBJ(search_unwind_table)); | |
89 | static char *find_dyn_list_name = STRINGIFY(UNW_OBJ(find_dyn_list)); | |
90 | ||
91 | static struct libunwind_descr * | |
92 | libunwind_descr (struct gdbarch *gdbarch) | |
93 | { | |
94 | return gdbarch_data (gdbarch, libunwind_descr_handle); | |
95 | } | |
96 | ||
97 | static void * | |
98 | libunwind_descr_init (struct gdbarch *gdbarch) | |
99 | { | |
100 | struct libunwind_descr *descr = GDBARCH_OBSTACK_ZALLOC (gdbarch, | |
101 | struct libunwind_descr); | |
102 | return descr; | |
103 | } | |
104 | ||
105 | void | |
106 | libunwind_frame_set_descr (struct gdbarch *gdbarch, struct libunwind_descr *descr) | |
107 | { | |
108 | struct libunwind_descr *arch_descr; | |
109 | ||
110 | gdb_assert (gdbarch != NULL); | |
111 | ||
112 | arch_descr = gdbarch_data (gdbarch, libunwind_descr_handle); | |
113 | ||
114 | if (arch_descr == NULL) | |
115 | { | |
116 | /* First time here. Must initialize data area. */ | |
117 | arch_descr = libunwind_descr_init (gdbarch); | |
030f20e1 | 118 | deprecated_set_gdbarch_data (gdbarch, libunwind_descr_handle, arch_descr); |
0e5d83e3 JJ |
119 | } |
120 | ||
121 | /* Copy new descriptor info into arch descriptor. */ | |
122 | arch_descr->gdb2uw = descr->gdb2uw; | |
123 | arch_descr->uw2gdb = descr->uw2gdb; | |
124 | arch_descr->is_fpreg = descr->is_fpreg; | |
125 | arch_descr->accessors = descr->accessors; | |
c5a27d9c | 126 | arch_descr->special_accessors = descr->special_accessors; |
0e5d83e3 JJ |
127 | } |
128 | ||
129 | static struct libunwind_frame_cache * | |
130 | libunwind_frame_cache (struct frame_info *next_frame, void **this_cache) | |
131 | { | |
132 | unw_accessors_t *acc; | |
133 | unw_addr_space_t as; | |
134 | unw_word_t fp; | |
135 | unw_regnum_t uw_sp_regnum; | |
136 | struct libunwind_frame_cache *cache; | |
137 | struct libunwind_descr *descr; | |
138 | int i, ret; | |
139 | ||
140 | if (*this_cache) | |
141 | return *this_cache; | |
142 | ||
143 | /* Allocate a new cache. */ | |
144 | cache = FRAME_OBSTACK_ZALLOC (struct libunwind_frame_cache); | |
145 | ||
93d42b30 DJ |
146 | /* We can assume we are unwinding a normal frame. Even if this is |
147 | for a signal trampoline, ia64 signal "trampolines" use a normal | |
148 | subroutine call to start the signal handler. */ | |
149 | cache->func_addr = frame_func_unwind (next_frame, NORMAL_FRAME); | |
c5a27d9c JJ |
150 | if (cache->func_addr == 0 |
151 | && frame_relative_level (next_frame) > 0 | |
152 | && get_frame_type (next_frame) != SIGTRAMP_FRAME) | |
153 | return NULL; | |
0e5d83e3 JJ |
154 | |
155 | /* Get a libunwind cursor to the previous frame. We do this by initializing | |
156 | a cursor. Libunwind treats a new cursor as the top of stack and will get | |
157 | the current register set via the libunwind register accessor. Now, we | |
158 | provide the platform-specific accessors and we set up the register accessor to use | |
159 | the frame register unwinding interfaces so that we properly get the registers for | |
160 | the current frame rather than the top. We then use the unw_step function to | |
161 | move the libunwind cursor back one frame. We can later use this cursor to find previous | |
162 | registers via the unw_get_reg interface which will invoke libunwind's special logic. */ | |
163 | descr = libunwind_descr (get_frame_arch (next_frame)); | |
164 | acc = descr->accessors; | |
165 | as = unw_create_addr_space_p (acc, | |
166 | TARGET_BYTE_ORDER == BFD_ENDIAN_BIG | |
167 | ? __BIG_ENDIAN | |
168 | : __LITTLE_ENDIAN); | |
169 | ||
170 | unw_init_remote_p (&cache->cursor, as, next_frame); | |
c5a27d9c JJ |
171 | if (unw_step_p (&cache->cursor) < 0) |
172 | return NULL; | |
0e5d83e3 JJ |
173 | |
174 | /* To get base address, get sp from previous frame. */ | |
175 | uw_sp_regnum = descr->gdb2uw (SP_REGNUM); | |
176 | ret = unw_get_reg_p (&cache->cursor, uw_sp_regnum, &fp); | |
177 | if (ret < 0) | |
8a3fe4f8 | 178 | error (_("Can't get libunwind sp register.")); |
0e5d83e3 JJ |
179 | |
180 | cache->base = (CORE_ADDR)fp; | |
181 | ||
182 | *this_cache = cache; | |
183 | return cache; | |
184 | } | |
185 | ||
503ff15d KB |
186 | unw_word_t |
187 | libunwind_find_dyn_list (unw_addr_space_t as, unw_dyn_info_t *di, void *arg) | |
0e5d83e3 | 188 | { |
503ff15d | 189 | return unw_find_dyn_list_p (as, di, arg); |
0e5d83e3 JJ |
190 | } |
191 | ||
192 | static const struct frame_unwind libunwind_frame_unwind = | |
193 | { | |
194 | NORMAL_FRAME, | |
195 | libunwind_frame_this_id, | |
196 | libunwind_frame_prev_register | |
197 | }; | |
198 | ||
199 | /* Verify if there is sufficient libunwind information for the frame to use | |
200 | libunwind frame unwinding. */ | |
201 | const struct frame_unwind * | |
202 | libunwind_frame_sniffer (struct frame_info *next_frame) | |
203 | { | |
204 | unw_cursor_t cursor; | |
205 | unw_accessors_t *acc; | |
206 | unw_addr_space_t as; | |
207 | struct libunwind_descr *descr; | |
208 | int i, ret; | |
209 | ||
210 | /* To test for libunwind unwind support, initialize a cursor to the current frame and try to back | |
211 | up. We use this same method when setting up the frame cache (see libunwind_frame_cache()). | |
212 | If libunwind returns success for this operation, it means that it has found sufficient | |
213 | libunwind unwinding information to do so. */ | |
214 | ||
215 | descr = libunwind_descr (get_frame_arch (next_frame)); | |
216 | acc = descr->accessors; | |
217 | as = unw_create_addr_space_p (acc, | |
218 | TARGET_BYTE_ORDER == BFD_ENDIAN_BIG | |
219 | ? __BIG_ENDIAN | |
220 | : __LITTLE_ENDIAN); | |
221 | ||
222 | ret = unw_init_remote_p (&cursor, as, next_frame); | |
223 | ||
c5a27d9c JJ |
224 | if (ret < 0) |
225 | return NULL; | |
226 | ||
227 | ||
228 | /* Check to see if we have libunwind info by checking if we are in a | |
229 | signal frame. If it doesn't return an error, we have libunwind info | |
230 | and can use libunwind. */ | |
231 | ret = unw_is_signal_frame_p (&cursor); | |
0e5d83e3 JJ |
232 | |
233 | if (ret < 0) | |
234 | return NULL; | |
235 | ||
236 | return &libunwind_frame_unwind; | |
237 | } | |
238 | ||
239 | void | |
240 | libunwind_frame_this_id (struct frame_info *next_frame, void **this_cache, | |
241 | struct frame_id *this_id) | |
242 | { | |
243 | struct libunwind_frame_cache *cache = | |
244 | libunwind_frame_cache (next_frame, this_cache); | |
245 | ||
c5a27d9c JJ |
246 | if (cache != NULL) |
247 | (*this_id) = frame_id_build (cache->base, cache->func_addr); | |
248 | else | |
249 | (*this_id) = null_frame_id; | |
0e5d83e3 JJ |
250 | } |
251 | ||
252 | void | |
253 | libunwind_frame_prev_register (struct frame_info *next_frame, void **this_cache, | |
254 | int regnum, int *optimizedp, | |
255 | enum lval_type *lvalp, CORE_ADDR *addrp, | |
f1b4b38e | 256 | int *realnump, gdb_byte *valuep) |
0e5d83e3 JJ |
257 | { |
258 | struct libunwind_frame_cache *cache = | |
259 | libunwind_frame_cache (next_frame, this_cache); | |
260 | ||
261 | void *ptr; | |
262 | unw_cursor_t *c; | |
263 | unw_save_loc_t sl; | |
264 | int i, ret; | |
265 | unw_word_t intval; | |
266 | unw_fpreg_t fpval; | |
267 | unw_regnum_t uw_regnum; | |
268 | struct libunwind_descr *descr; | |
269 | ||
c5a27d9c JJ |
270 | if (cache == NULL) |
271 | return; | |
272 | ||
0e5d83e3 JJ |
273 | /* Convert from gdb register number to libunwind register number. */ |
274 | descr = libunwind_descr (get_frame_arch (next_frame)); | |
275 | uw_regnum = descr->gdb2uw (regnum); | |
276 | ||
277 | gdb_assert (regnum >= 0); | |
278 | ||
279 | if (!target_has_registers) | |
8a3fe4f8 | 280 | error (_("No registers.")); |
0e5d83e3 JJ |
281 | |
282 | *optimizedp = 0; | |
283 | *addrp = 0; | |
284 | *lvalp = not_lval; | |
285 | *realnump = -1; | |
286 | ||
6672f2ae AS |
287 | if (valuep) |
288 | memset (valuep, 0, register_size (current_gdbarch, regnum)); | |
0e5d83e3 JJ |
289 | |
290 | if (uw_regnum < 0) | |
291 | return; | |
292 | ||
293 | /* To get the previous register, we use the libunwind register APIs with | |
294 | the cursor we have already pushed back to the previous frame. */ | |
295 | ||
296 | if (descr->is_fpreg (uw_regnum)) | |
297 | { | |
298 | ret = unw_get_fpreg_p (&cache->cursor, uw_regnum, &fpval); | |
299 | ptr = &fpval; | |
300 | } | |
301 | else | |
302 | { | |
303 | ret = unw_get_reg_p (&cache->cursor, uw_regnum, &intval); | |
304 | ptr = &intval; | |
305 | } | |
306 | ||
307 | if (ret < 0) | |
308 | return; | |
309 | ||
6672f2ae AS |
310 | if (valuep) |
311 | memcpy (valuep, ptr, register_size (current_gdbarch, regnum)); | |
0e5d83e3 JJ |
312 | |
313 | if (unw_get_saveloc_p (&cache->cursor, uw_regnum, &sl) < 0) | |
314 | return; | |
315 | ||
316 | switch (sl.type) | |
317 | { | |
318 | case UNW_SLT_NONE: | |
319 | *optimizedp = 1; | |
320 | break; | |
321 | ||
322 | case UNW_SLT_MEMORY: | |
323 | *lvalp = lval_memory; | |
324 | *addrp = sl.u.addr; | |
325 | break; | |
326 | ||
327 | case UNW_SLT_REG: | |
328 | *lvalp = lval_register; | |
329 | *realnump = regnum; | |
330 | break; | |
331 | } | |
332 | } | |
333 | ||
334 | CORE_ADDR | |
335 | libunwind_frame_base_address (struct frame_info *next_frame, void **this_cache) | |
336 | { | |
337 | struct libunwind_frame_cache *cache = | |
338 | libunwind_frame_cache (next_frame, this_cache); | |
339 | ||
c5a27d9c JJ |
340 | if (cache == NULL) |
341 | return (CORE_ADDR)NULL; | |
0e5d83e3 JJ |
342 | return cache->base; |
343 | } | |
344 | ||
345 | /* The following is a glue routine to call the libunwind unwind table | |
346 | search function to get unwind information for a specified ip address. */ | |
347 | int | |
348 | libunwind_search_unwind_table (void *as, long ip, void *di, | |
349 | void *pi, int need_unwind_info, void *args) | |
350 | { | |
351 | return unw_search_unwind_table_p (*(unw_addr_space_t *)as, (unw_word_t )ip, | |
352 | di, pi, need_unwind_info, args); | |
353 | } | |
354 | ||
c5a27d9c JJ |
355 | /* Verify if we are in a sigtramp frame and we can use libunwind to unwind. */ |
356 | const struct frame_unwind * | |
357 | libunwind_sigtramp_frame_sniffer (struct frame_info *next_frame) | |
358 | { | |
359 | unw_cursor_t cursor; | |
360 | unw_accessors_t *acc; | |
361 | unw_addr_space_t as; | |
362 | struct libunwind_descr *descr; | |
363 | int i, ret; | |
364 | ||
365 | /* To test for libunwind unwind support, initialize a cursor to the | |
366 | current frame and try to back up. We use this same method when | |
367 | setting up the frame cache (see libunwind_frame_cache()). If | |
368 | libunwind returns success for this operation, it means that it | |
369 | has found sufficient libunwind unwinding information to do | |
370 | so. */ | |
371 | ||
372 | descr = libunwind_descr (get_frame_arch (next_frame)); | |
373 | acc = descr->accessors; | |
374 | as = unw_create_addr_space_p (acc, | |
375 | TARGET_BYTE_ORDER == BFD_ENDIAN_BIG | |
376 | ? __BIG_ENDIAN | |
377 | : __LITTLE_ENDIAN); | |
378 | ||
379 | ret = unw_init_remote_p (&cursor, as, next_frame); | |
380 | ||
381 | if (ret < 0) | |
382 | return NULL; | |
383 | ||
384 | /* Check to see if we are in a signal frame. */ | |
385 | ret = unw_is_signal_frame_p (&cursor); | |
386 | if (ret > 0) | |
387 | return &libunwind_frame_unwind; | |
388 | ||
389 | return NULL; | |
390 | } | |
391 | ||
392 | /* The following routine is for accessing special registers of the top frame. | |
393 | A special set of accessors must be given that work without frame info. | |
394 | This is used by ia64 to access the rse registers r32-r127. While they | |
395 | are usually located at BOF, this is not always true and only the libunwind | |
396 | info can decipher where they actually are. */ | |
397 | int | |
398 | libunwind_get_reg_special (struct gdbarch *gdbarch, int regnum, void *buf) | |
399 | { | |
400 | unw_cursor_t cursor; | |
401 | unw_accessors_t *acc; | |
402 | unw_addr_space_t as; | |
403 | struct libunwind_descr *descr; | |
404 | int ret; | |
405 | unw_regnum_t uw_regnum; | |
406 | unw_word_t intval; | |
407 | unw_fpreg_t fpval; | |
408 | void *ptr; | |
409 | ||
410 | ||
411 | descr = libunwind_descr (gdbarch); | |
412 | acc = descr->special_accessors; | |
413 | as = unw_create_addr_space_p (acc, | |
414 | TARGET_BYTE_ORDER == BFD_ENDIAN_BIG | |
415 | ? __BIG_ENDIAN | |
416 | : __LITTLE_ENDIAN); | |
417 | ||
418 | ret = unw_init_remote_p (&cursor, as, NULL); | |
419 | if (ret < 0) | |
420 | return -1; | |
421 | ||
422 | uw_regnum = descr->gdb2uw (regnum); | |
423 | ||
424 | if (descr->is_fpreg (uw_regnum)) | |
425 | { | |
426 | ret = unw_get_fpreg_p (&cursor, uw_regnum, &fpval); | |
427 | ptr = &fpval; | |
428 | } | |
429 | else | |
430 | { | |
431 | ret = unw_get_reg_p (&cursor, uw_regnum, &intval); | |
432 | ptr = &intval; | |
433 | } | |
434 | ||
435 | if (ret < 0) | |
436 | return -1; | |
437 | ||
438 | if (buf) | |
439 | memcpy (buf, ptr, register_size (current_gdbarch, regnum)); | |
440 | ||
441 | return 0; | |
442 | } | |
443 | ||
0e5d83e3 JJ |
444 | static int |
445 | libunwind_load (void) | |
446 | { | |
447 | void *handle; | |
448 | ||
449 | handle = dlopen (LIBUNWIND_SO, RTLD_NOW); | |
450 | if (handle == NULL) | |
451 | return 0; | |
452 | ||
453 | /* Initialize pointers to the dynamic library functions we will use. */ | |
454 | ||
455 | unw_get_reg_p = dlsym (handle, get_reg_name); | |
456 | if (unw_get_reg_p == NULL) | |
457 | return 0; | |
458 | ||
459 | unw_get_fpreg_p = dlsym (handle, get_fpreg_name); | |
460 | if (unw_get_fpreg_p == NULL) | |
461 | return 0; | |
462 | ||
463 | unw_get_saveloc_p = dlsym (handle, get_saveloc_name); | |
464 | if (unw_get_saveloc_p == NULL) | |
465 | return 0; | |
466 | ||
c5a27d9c JJ |
467 | unw_is_signal_frame_p = dlsym (handle, is_signal_frame_name); |
468 | if (unw_is_signal_frame_p == NULL) | |
469 | return 0; | |
470 | ||
0e5d83e3 JJ |
471 | unw_step_p = dlsym (handle, step_name); |
472 | if (unw_step_p == NULL) | |
473 | return 0; | |
474 | ||
475 | unw_init_remote_p = dlsym (handle, init_remote_name); | |
476 | if (unw_init_remote_p == NULL) | |
477 | return 0; | |
478 | ||
479 | unw_create_addr_space_p = dlsym (handle, create_addr_space_name); | |
480 | if (unw_create_addr_space_p == NULL) | |
481 | return 0; | |
482 | ||
483 | unw_search_unwind_table_p = dlsym (handle, search_unwind_table_name); | |
484 | if (unw_search_unwind_table_p == NULL) | |
485 | return 0; | |
486 | ||
487 | unw_find_dyn_list_p = dlsym (handle, find_dyn_list_name); | |
488 | if (unw_find_dyn_list_p == NULL) | |
489 | return 0; | |
490 | ||
491 | return 1; | |
492 | } | |
493 | ||
494 | int | |
495 | libunwind_is_initialized (void) | |
496 | { | |
497 | return libunwind_initialized; | |
498 | } | |
499 | ||
500 | /* Provide a prototype to silence -Wmissing-prototypes. */ | |
501 | void _initialize_libunwind_frame (void); | |
502 | ||
503 | void | |
504 | _initialize_libunwind_frame (void) | |
505 | { | |
030f20e1 | 506 | libunwind_descr_handle = gdbarch_data_register_post_init (libunwind_descr_init); |
0e5d83e3 JJ |
507 | |
508 | libunwind_initialized = libunwind_load (); | |
509 | } |