| 1 | /* Frame unwinder for frames using the libunwind library. |
| 2 | |
| 3 | Copyright 2003, 2004 Free Software Foundation, Inc. |
| 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 |
| 21 | Foundation, Inc., 59 Temple Place - Suite 330, |
| 22 | Boston, MA 02111-1307, USA. */ |
| 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 | |
| 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 *); |
| 52 | static int (*unw_is_signal_frame_p) (unw_cursor_t *); |
| 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 *); |
| 58 | static unw_word_t (*unw_find_dyn_list_p) (unw_addr_space_t, unw_dyn_info_t *, |
| 59 | void *); |
| 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 | |
| 75 | #ifndef LIBUNWIND_SO |
| 76 | #define LIBUNWIND_SO "libunwind-" STRINGIFY(UNW_TARGET) ".so" |
| 77 | #endif |
| 78 | |
| 79 | static char *get_reg_name = STRINGIFY(UNW_OBJ(get_reg)); |
| 80 | static char *get_fpreg_name = STRINGIFY(UNW_OBJ(get_fpreg)); |
| 81 | static char *get_saveloc_name = STRINGIFY(UNW_OBJ(get_save_loc)); |
| 82 | static char *is_signal_frame_name = STRINGIFY(UNW_OBJ(is_signal_frame)); |
| 83 | static char *step_name = STRINGIFY(UNW_OBJ(step)); |
| 84 | static char *init_remote_name = STRINGIFY(UNW_OBJ(init_remote)); |
| 85 | static char *create_addr_space_name = STRINGIFY(UNW_OBJ(create_addr_space)); |
| 86 | static char *search_unwind_table_name = STRINGIFY(UNW_OBJ(search_unwind_table)); |
| 87 | static char *find_dyn_list_name = STRINGIFY(UNW_OBJ(find_dyn_list)); |
| 88 | |
| 89 | static struct libunwind_descr * |
| 90 | libunwind_descr (struct gdbarch *gdbarch) |
| 91 | { |
| 92 | return gdbarch_data (gdbarch, libunwind_descr_handle); |
| 93 | } |
| 94 | |
| 95 | static void * |
| 96 | libunwind_descr_init (struct gdbarch *gdbarch) |
| 97 | { |
| 98 | struct libunwind_descr *descr = GDBARCH_OBSTACK_ZALLOC (gdbarch, |
| 99 | struct libunwind_descr); |
| 100 | return descr; |
| 101 | } |
| 102 | |
| 103 | void |
| 104 | libunwind_frame_set_descr (struct gdbarch *gdbarch, struct libunwind_descr *descr) |
| 105 | { |
| 106 | struct libunwind_descr *arch_descr; |
| 107 | |
| 108 | gdb_assert (gdbarch != NULL); |
| 109 | |
| 110 | arch_descr = gdbarch_data (gdbarch, libunwind_descr_handle); |
| 111 | |
| 112 | if (arch_descr == NULL) |
| 113 | { |
| 114 | /* First time here. Must initialize data area. */ |
| 115 | arch_descr = libunwind_descr_init (gdbarch); |
| 116 | deprecated_set_gdbarch_data (gdbarch, libunwind_descr_handle, arch_descr); |
| 117 | } |
| 118 | |
| 119 | /* Copy new descriptor info into arch descriptor. */ |
| 120 | arch_descr->gdb2uw = descr->gdb2uw; |
| 121 | arch_descr->uw2gdb = descr->uw2gdb; |
| 122 | arch_descr->is_fpreg = descr->is_fpreg; |
| 123 | arch_descr->accessors = descr->accessors; |
| 124 | arch_descr->special_accessors = descr->special_accessors; |
| 125 | } |
| 126 | |
| 127 | static struct libunwind_frame_cache * |
| 128 | libunwind_frame_cache (struct frame_info *next_frame, void **this_cache) |
| 129 | { |
| 130 | unw_accessors_t *acc; |
| 131 | unw_addr_space_t as; |
| 132 | unw_word_t fp; |
| 133 | unw_regnum_t uw_sp_regnum; |
| 134 | struct libunwind_frame_cache *cache; |
| 135 | struct libunwind_descr *descr; |
| 136 | int i, ret; |
| 137 | |
| 138 | if (*this_cache) |
| 139 | return *this_cache; |
| 140 | |
| 141 | /* Allocate a new cache. */ |
| 142 | cache = FRAME_OBSTACK_ZALLOC (struct libunwind_frame_cache); |
| 143 | |
| 144 | cache->func_addr = frame_func_unwind (next_frame); |
| 145 | if (cache->func_addr == 0 |
| 146 | && frame_relative_level (next_frame) > 0 |
| 147 | && get_frame_type (next_frame) != SIGTRAMP_FRAME) |
| 148 | return NULL; |
| 149 | |
| 150 | /* Get a libunwind cursor to the previous frame. We do this by initializing |
| 151 | a cursor. Libunwind treats a new cursor as the top of stack and will get |
| 152 | the current register set via the libunwind register accessor. Now, we |
| 153 | provide the platform-specific accessors and we set up the register accessor to use |
| 154 | the frame register unwinding interfaces so that we properly get the registers for |
| 155 | the current frame rather than the top. We then use the unw_step function to |
| 156 | move the libunwind cursor back one frame. We can later use this cursor to find previous |
| 157 | registers via the unw_get_reg interface which will invoke libunwind's special logic. */ |
| 158 | descr = libunwind_descr (get_frame_arch (next_frame)); |
| 159 | acc = descr->accessors; |
| 160 | as = unw_create_addr_space_p (acc, |
| 161 | TARGET_BYTE_ORDER == BFD_ENDIAN_BIG |
| 162 | ? __BIG_ENDIAN |
| 163 | : __LITTLE_ENDIAN); |
| 164 | |
| 165 | unw_init_remote_p (&cache->cursor, as, next_frame); |
| 166 | if (unw_step_p (&cache->cursor) < 0) |
| 167 | return NULL; |
| 168 | |
| 169 | /* To get base address, get sp from previous frame. */ |
| 170 | uw_sp_regnum = descr->gdb2uw (SP_REGNUM); |
| 171 | ret = unw_get_reg_p (&cache->cursor, uw_sp_regnum, &fp); |
| 172 | if (ret < 0) |
| 173 | error (_("Can't get libunwind sp register.")); |
| 174 | |
| 175 | cache->base = (CORE_ADDR)fp; |
| 176 | |
| 177 | *this_cache = cache; |
| 178 | return cache; |
| 179 | } |
| 180 | |
| 181 | unw_word_t |
| 182 | libunwind_find_dyn_list (unw_addr_space_t as, unw_dyn_info_t *di, void *arg) |
| 183 | { |
| 184 | return unw_find_dyn_list_p (as, di, arg); |
| 185 | } |
| 186 | |
| 187 | static const struct frame_unwind libunwind_frame_unwind = |
| 188 | { |
| 189 | NORMAL_FRAME, |
| 190 | libunwind_frame_this_id, |
| 191 | libunwind_frame_prev_register |
| 192 | }; |
| 193 | |
| 194 | /* Verify if there is sufficient libunwind information for the frame to use |
| 195 | libunwind frame unwinding. */ |
| 196 | const struct frame_unwind * |
| 197 | libunwind_frame_sniffer (struct frame_info *next_frame) |
| 198 | { |
| 199 | unw_cursor_t cursor; |
| 200 | unw_accessors_t *acc; |
| 201 | unw_addr_space_t as; |
| 202 | struct libunwind_descr *descr; |
| 203 | int i, ret; |
| 204 | |
| 205 | /* To test for libunwind unwind support, initialize a cursor to the current frame and try to back |
| 206 | up. We use this same method when setting up the frame cache (see libunwind_frame_cache()). |
| 207 | If libunwind returns success for this operation, it means that it has found sufficient |
| 208 | libunwind unwinding information to do so. */ |
| 209 | |
| 210 | descr = libunwind_descr (get_frame_arch (next_frame)); |
| 211 | acc = descr->accessors; |
| 212 | as = unw_create_addr_space_p (acc, |
| 213 | TARGET_BYTE_ORDER == BFD_ENDIAN_BIG |
| 214 | ? __BIG_ENDIAN |
| 215 | : __LITTLE_ENDIAN); |
| 216 | |
| 217 | ret = unw_init_remote_p (&cursor, as, next_frame); |
| 218 | |
| 219 | if (ret < 0) |
| 220 | return NULL; |
| 221 | |
| 222 | |
| 223 | /* Check to see if we have libunwind info by checking if we are in a |
| 224 | signal frame. If it doesn't return an error, we have libunwind info |
| 225 | and can use libunwind. */ |
| 226 | ret = unw_is_signal_frame_p (&cursor); |
| 227 | |
| 228 | if (ret < 0) |
| 229 | return NULL; |
| 230 | |
| 231 | return &libunwind_frame_unwind; |
| 232 | } |
| 233 | |
| 234 | void |
| 235 | libunwind_frame_this_id (struct frame_info *next_frame, void **this_cache, |
| 236 | struct frame_id *this_id) |
| 237 | { |
| 238 | struct libunwind_frame_cache *cache = |
| 239 | libunwind_frame_cache (next_frame, this_cache); |
| 240 | |
| 241 | if (cache != NULL) |
| 242 | (*this_id) = frame_id_build (cache->base, cache->func_addr); |
| 243 | else |
| 244 | (*this_id) = null_frame_id; |
| 245 | } |
| 246 | |
| 247 | void |
| 248 | libunwind_frame_prev_register (struct frame_info *next_frame, void **this_cache, |
| 249 | int regnum, int *optimizedp, |
| 250 | enum lval_type *lvalp, CORE_ADDR *addrp, |
| 251 | int *realnump, void *valuep) |
| 252 | { |
| 253 | struct libunwind_frame_cache *cache = |
| 254 | libunwind_frame_cache (next_frame, this_cache); |
| 255 | |
| 256 | void *ptr; |
| 257 | unw_cursor_t *c; |
| 258 | unw_save_loc_t sl; |
| 259 | int i, ret; |
| 260 | unw_word_t intval; |
| 261 | unw_fpreg_t fpval; |
| 262 | unw_regnum_t uw_regnum; |
| 263 | struct libunwind_descr *descr; |
| 264 | |
| 265 | if (cache == NULL) |
| 266 | return; |
| 267 | |
| 268 | /* Convert from gdb register number to libunwind register number. */ |
| 269 | descr = libunwind_descr (get_frame_arch (next_frame)); |
| 270 | uw_regnum = descr->gdb2uw (regnum); |
| 271 | |
| 272 | gdb_assert (regnum >= 0); |
| 273 | |
| 274 | if (!target_has_registers) |
| 275 | error (_("No registers.")); |
| 276 | |
| 277 | *optimizedp = 0; |
| 278 | *addrp = 0; |
| 279 | *lvalp = not_lval; |
| 280 | *realnump = -1; |
| 281 | |
| 282 | if (valuep) |
| 283 | memset (valuep, 0, register_size (current_gdbarch, regnum)); |
| 284 | |
| 285 | if (uw_regnum < 0) |
| 286 | return; |
| 287 | |
| 288 | /* To get the previous register, we use the libunwind register APIs with |
| 289 | the cursor we have already pushed back to the previous frame. */ |
| 290 | |
| 291 | if (descr->is_fpreg (uw_regnum)) |
| 292 | { |
| 293 | ret = unw_get_fpreg_p (&cache->cursor, uw_regnum, &fpval); |
| 294 | ptr = &fpval; |
| 295 | } |
| 296 | else |
| 297 | { |
| 298 | ret = unw_get_reg_p (&cache->cursor, uw_regnum, &intval); |
| 299 | ptr = &intval; |
| 300 | } |
| 301 | |
| 302 | if (ret < 0) |
| 303 | return; |
| 304 | |
| 305 | if (valuep) |
| 306 | memcpy (valuep, ptr, register_size (current_gdbarch, regnum)); |
| 307 | |
| 308 | if (unw_get_saveloc_p (&cache->cursor, uw_regnum, &sl) < 0) |
| 309 | return; |
| 310 | |
| 311 | switch (sl.type) |
| 312 | { |
| 313 | case UNW_SLT_NONE: |
| 314 | *optimizedp = 1; |
| 315 | break; |
| 316 | |
| 317 | case UNW_SLT_MEMORY: |
| 318 | *lvalp = lval_memory; |
| 319 | *addrp = sl.u.addr; |
| 320 | break; |
| 321 | |
| 322 | case UNW_SLT_REG: |
| 323 | *lvalp = lval_register; |
| 324 | *realnump = regnum; |
| 325 | break; |
| 326 | } |
| 327 | } |
| 328 | |
| 329 | CORE_ADDR |
| 330 | libunwind_frame_base_address (struct frame_info *next_frame, void **this_cache) |
| 331 | { |
| 332 | struct libunwind_frame_cache *cache = |
| 333 | libunwind_frame_cache (next_frame, this_cache); |
| 334 | |
| 335 | if (cache == NULL) |
| 336 | return (CORE_ADDR)NULL; |
| 337 | return cache->base; |
| 338 | } |
| 339 | |
| 340 | /* The following is a glue routine to call the libunwind unwind table |
| 341 | search function to get unwind information for a specified ip address. */ |
| 342 | int |
| 343 | libunwind_search_unwind_table (void *as, long ip, void *di, |
| 344 | void *pi, int need_unwind_info, void *args) |
| 345 | { |
| 346 | return unw_search_unwind_table_p (*(unw_addr_space_t *)as, (unw_word_t )ip, |
| 347 | di, pi, need_unwind_info, args); |
| 348 | } |
| 349 | |
| 350 | /* Verify if we are in a sigtramp frame and we can use libunwind to unwind. */ |
| 351 | const struct frame_unwind * |
| 352 | libunwind_sigtramp_frame_sniffer (struct frame_info *next_frame) |
| 353 | { |
| 354 | unw_cursor_t cursor; |
| 355 | unw_accessors_t *acc; |
| 356 | unw_addr_space_t as; |
| 357 | struct libunwind_descr *descr; |
| 358 | int i, ret; |
| 359 | |
| 360 | /* To test for libunwind unwind support, initialize a cursor to the |
| 361 | current frame and try to back up. We use this same method when |
| 362 | setting up the frame cache (see libunwind_frame_cache()). If |
| 363 | libunwind returns success for this operation, it means that it |
| 364 | has found sufficient libunwind unwinding information to do |
| 365 | so. */ |
| 366 | |
| 367 | descr = libunwind_descr (get_frame_arch (next_frame)); |
| 368 | acc = descr->accessors; |
| 369 | as = unw_create_addr_space_p (acc, |
| 370 | TARGET_BYTE_ORDER == BFD_ENDIAN_BIG |
| 371 | ? __BIG_ENDIAN |
| 372 | : __LITTLE_ENDIAN); |
| 373 | |
| 374 | ret = unw_init_remote_p (&cursor, as, next_frame); |
| 375 | |
| 376 | if (ret < 0) |
| 377 | return NULL; |
| 378 | |
| 379 | /* Check to see if we are in a signal frame. */ |
| 380 | ret = unw_is_signal_frame_p (&cursor); |
| 381 | if (ret > 0) |
| 382 | return &libunwind_frame_unwind; |
| 383 | |
| 384 | return NULL; |
| 385 | } |
| 386 | |
| 387 | /* The following routine is for accessing special registers of the top frame. |
| 388 | A special set of accessors must be given that work without frame info. |
| 389 | This is used by ia64 to access the rse registers r32-r127. While they |
| 390 | are usually located at BOF, this is not always true and only the libunwind |
| 391 | info can decipher where they actually are. */ |
| 392 | int |
| 393 | libunwind_get_reg_special (struct gdbarch *gdbarch, int regnum, void *buf) |
| 394 | { |
| 395 | unw_cursor_t cursor; |
| 396 | unw_accessors_t *acc; |
| 397 | unw_addr_space_t as; |
| 398 | struct libunwind_descr *descr; |
| 399 | int ret; |
| 400 | unw_regnum_t uw_regnum; |
| 401 | unw_word_t intval; |
| 402 | unw_fpreg_t fpval; |
| 403 | void *ptr; |
| 404 | |
| 405 | |
| 406 | descr = libunwind_descr (gdbarch); |
| 407 | acc = descr->special_accessors; |
| 408 | as = unw_create_addr_space_p (acc, |
| 409 | TARGET_BYTE_ORDER == BFD_ENDIAN_BIG |
| 410 | ? __BIG_ENDIAN |
| 411 | : __LITTLE_ENDIAN); |
| 412 | |
| 413 | ret = unw_init_remote_p (&cursor, as, NULL); |
| 414 | if (ret < 0) |
| 415 | return -1; |
| 416 | |
| 417 | uw_regnum = descr->gdb2uw (regnum); |
| 418 | |
| 419 | if (descr->is_fpreg (uw_regnum)) |
| 420 | { |
| 421 | ret = unw_get_fpreg_p (&cursor, uw_regnum, &fpval); |
| 422 | ptr = &fpval; |
| 423 | } |
| 424 | else |
| 425 | { |
| 426 | ret = unw_get_reg_p (&cursor, uw_regnum, &intval); |
| 427 | ptr = &intval; |
| 428 | } |
| 429 | |
| 430 | if (ret < 0) |
| 431 | return -1; |
| 432 | |
| 433 | if (buf) |
| 434 | memcpy (buf, ptr, register_size (current_gdbarch, regnum)); |
| 435 | |
| 436 | return 0; |
| 437 | } |
| 438 | |
| 439 | static int |
| 440 | libunwind_load (void) |
| 441 | { |
| 442 | void *handle; |
| 443 | |
| 444 | handle = dlopen (LIBUNWIND_SO, RTLD_NOW); |
| 445 | if (handle == NULL) |
| 446 | return 0; |
| 447 | |
| 448 | /* Initialize pointers to the dynamic library functions we will use. */ |
| 449 | |
| 450 | unw_get_reg_p = dlsym (handle, get_reg_name); |
| 451 | if (unw_get_reg_p == NULL) |
| 452 | return 0; |
| 453 | |
| 454 | unw_get_fpreg_p = dlsym (handle, get_fpreg_name); |
| 455 | if (unw_get_fpreg_p == NULL) |
| 456 | return 0; |
| 457 | |
| 458 | unw_get_saveloc_p = dlsym (handle, get_saveloc_name); |
| 459 | if (unw_get_saveloc_p == NULL) |
| 460 | return 0; |
| 461 | |
| 462 | unw_is_signal_frame_p = dlsym (handle, is_signal_frame_name); |
| 463 | if (unw_is_signal_frame_p == NULL) |
| 464 | return 0; |
| 465 | |
| 466 | unw_step_p = dlsym (handle, step_name); |
| 467 | if (unw_step_p == NULL) |
| 468 | return 0; |
| 469 | |
| 470 | unw_init_remote_p = dlsym (handle, init_remote_name); |
| 471 | if (unw_init_remote_p == NULL) |
| 472 | return 0; |
| 473 | |
| 474 | unw_create_addr_space_p = dlsym (handle, create_addr_space_name); |
| 475 | if (unw_create_addr_space_p == NULL) |
| 476 | return 0; |
| 477 | |
| 478 | unw_search_unwind_table_p = dlsym (handle, search_unwind_table_name); |
| 479 | if (unw_search_unwind_table_p == NULL) |
| 480 | return 0; |
| 481 | |
| 482 | unw_find_dyn_list_p = dlsym (handle, find_dyn_list_name); |
| 483 | if (unw_find_dyn_list_p == NULL) |
| 484 | return 0; |
| 485 | |
| 486 | return 1; |
| 487 | } |
| 488 | |
| 489 | int |
| 490 | libunwind_is_initialized (void) |
| 491 | { |
| 492 | return libunwind_initialized; |
| 493 | } |
| 494 | |
| 495 | /* Provide a prototype to silence -Wmissing-prototypes. */ |
| 496 | void _initialize_libunwind_frame (void); |
| 497 | |
| 498 | void |
| 499 | _initialize_libunwind_frame (void) |
| 500 | { |
| 501 | libunwind_descr_handle = gdbarch_data_register_post_init (libunwind_descr_init); |
| 502 | |
| 503 | libunwind_initialized = libunwind_load (); |
| 504 | } |