| 1 | /* Get info from stack frames; convert between frames, blocks, |
| 2 | functions and pc values. |
| 3 | |
| 4 | Copyright (C) 1986-2019 Free Software Foundation, Inc. |
| 5 | |
| 6 | This file is part of GDB. |
| 7 | |
| 8 | This program is free software; you can redistribute it and/or modify |
| 9 | it under the terms of the GNU General Public License as published by |
| 10 | the Free Software Foundation; either version 3 of the License, or |
| 11 | (at your option) any later version. |
| 12 | |
| 13 | This program is distributed in the hope that it will be useful, |
| 14 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 16 | GNU General Public License for more details. |
| 17 | |
| 18 | You should have received a copy of the GNU General Public License |
| 19 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| 20 | |
| 21 | #include "defs.h" |
| 22 | #include "symtab.h" |
| 23 | #include "bfd.h" |
| 24 | #include "objfiles.h" |
| 25 | #include "frame.h" |
| 26 | #include "gdbcore.h" |
| 27 | #include "value.h" |
| 28 | #include "target.h" |
| 29 | #include "inferior.h" |
| 30 | #include "annotate.h" |
| 31 | #include "regcache.h" |
| 32 | #include "dummy-frame.h" |
| 33 | #include "command.h" |
| 34 | #include "gdbcmd.h" |
| 35 | #include "block.h" |
| 36 | #include "inline-frame.h" |
| 37 | |
| 38 | /* Return the innermost lexical block in execution in a specified |
| 39 | stack frame. The frame address is assumed valid. |
| 40 | |
| 41 | If ADDR_IN_BLOCK is non-zero, set *ADDR_IN_BLOCK to the exact code |
| 42 | address we used to choose the block. We use this to find a source |
| 43 | line, to decide which macro definitions are in scope. |
| 44 | |
| 45 | The value returned in *ADDR_IN_BLOCK isn't necessarily the frame's |
| 46 | PC, and may not really be a valid PC at all. For example, in the |
| 47 | caller of a function declared to never return, the code at the |
| 48 | return address will never be reached, so the call instruction may |
| 49 | be the very last instruction in the block. So the address we use |
| 50 | to choose the block is actually one byte before the return address |
| 51 | --- hopefully pointing us at the call instruction, or its delay |
| 52 | slot instruction. */ |
| 53 | |
| 54 | const struct block * |
| 55 | get_frame_block (struct frame_info *frame, CORE_ADDR *addr_in_block) |
| 56 | { |
| 57 | CORE_ADDR pc; |
| 58 | const struct block *bl; |
| 59 | int inline_count; |
| 60 | |
| 61 | if (!get_frame_address_in_block_if_available (frame, &pc)) |
| 62 | return NULL; |
| 63 | |
| 64 | if (addr_in_block) |
| 65 | *addr_in_block = pc; |
| 66 | |
| 67 | bl = block_for_pc (pc); |
| 68 | if (bl == NULL) |
| 69 | return NULL; |
| 70 | |
| 71 | inline_count = frame_inlined_callees (frame); |
| 72 | |
| 73 | while (inline_count > 0) |
| 74 | { |
| 75 | if (block_inlined_p (bl)) |
| 76 | inline_count--; |
| 77 | |
| 78 | bl = BLOCK_SUPERBLOCK (bl); |
| 79 | gdb_assert (bl != NULL); |
| 80 | } |
| 81 | |
| 82 | return bl; |
| 83 | } |
| 84 | |
| 85 | CORE_ADDR |
| 86 | get_pc_function_start (CORE_ADDR pc) |
| 87 | { |
| 88 | const struct block *bl; |
| 89 | struct bound_minimal_symbol msymbol; |
| 90 | |
| 91 | bl = block_for_pc (pc); |
| 92 | if (bl) |
| 93 | { |
| 94 | struct symbol *symbol = block_linkage_function (bl); |
| 95 | |
| 96 | if (symbol) |
| 97 | { |
| 98 | bl = SYMBOL_BLOCK_VALUE (symbol); |
| 99 | return BLOCK_ENTRY_PC (bl); |
| 100 | } |
| 101 | } |
| 102 | |
| 103 | msymbol = lookup_minimal_symbol_by_pc (pc); |
| 104 | if (msymbol.minsym) |
| 105 | { |
| 106 | CORE_ADDR fstart = BMSYMBOL_VALUE_ADDRESS (msymbol); |
| 107 | |
| 108 | if (find_pc_section (fstart)) |
| 109 | return fstart; |
| 110 | } |
| 111 | |
| 112 | return 0; |
| 113 | } |
| 114 | |
| 115 | /* Return the symbol for the function executing in frame FRAME. */ |
| 116 | |
| 117 | struct symbol * |
| 118 | get_frame_function (struct frame_info *frame) |
| 119 | { |
| 120 | const struct block *bl = get_frame_block (frame, 0); |
| 121 | |
| 122 | if (bl == NULL) |
| 123 | return NULL; |
| 124 | |
| 125 | while (BLOCK_FUNCTION (bl) == NULL && BLOCK_SUPERBLOCK (bl) != NULL) |
| 126 | bl = BLOCK_SUPERBLOCK (bl); |
| 127 | |
| 128 | return BLOCK_FUNCTION (bl); |
| 129 | } |
| 130 | \f |
| 131 | |
| 132 | /* Return the function containing pc value PC in section SECTION. |
| 133 | Returns 0 if function is not known. */ |
| 134 | |
| 135 | struct symbol * |
| 136 | find_pc_sect_function (CORE_ADDR pc, struct obj_section *section) |
| 137 | { |
| 138 | const struct block *b = block_for_pc_sect (pc, section); |
| 139 | |
| 140 | if (b == 0) |
| 141 | return 0; |
| 142 | return block_linkage_function (b); |
| 143 | } |
| 144 | |
| 145 | /* Return the function containing pc value PC. |
| 146 | Returns 0 if function is not known. |
| 147 | Backward compatibility, no section */ |
| 148 | |
| 149 | struct symbol * |
| 150 | find_pc_function (CORE_ADDR pc) |
| 151 | { |
| 152 | return find_pc_sect_function (pc, find_pc_mapped_section (pc)); |
| 153 | } |
| 154 | |
| 155 | /* See symtab.h. */ |
| 156 | |
| 157 | struct symbol * |
| 158 | find_pc_sect_containing_function (CORE_ADDR pc, struct obj_section *section) |
| 159 | { |
| 160 | const block *bl = block_for_pc_sect (pc, section); |
| 161 | |
| 162 | if (bl == nullptr) |
| 163 | return nullptr; |
| 164 | |
| 165 | return block_containing_function (bl); |
| 166 | } |
| 167 | |
| 168 | /* These variables are used to cache the most recent result of |
| 169 | find_pc_partial_function. |
| 170 | |
| 171 | The addresses cache_pc_function_low and cache_pc_function_high |
| 172 | record the range in which PC was found during the most recent |
| 173 | successful lookup. When the function occupies a single contiguous |
| 174 | address range, these values correspond to the low and high |
| 175 | addresses of the function. (The high address is actually one byte |
| 176 | beyond the last byte of the function.) For a function with more |
| 177 | than one (non-contiguous) range, the range in which PC was found is |
| 178 | used to set the cache bounds. |
| 179 | |
| 180 | When determining whether or not these cached values apply to a |
| 181 | particular PC value, PC must be within the range specified by |
| 182 | cache_pc_function_low and cache_pc_function_high. In addition to |
| 183 | PC being in that range, cache_pc_section must also match PC's |
| 184 | section. See find_pc_partial_function() for details on both the |
| 185 | comparison as well as how PC's section is determined. |
| 186 | |
| 187 | The other values aren't used for determining whether the cache |
| 188 | applies, but are used for setting the outputs from |
| 189 | find_pc_partial_function. cache_pc_function_low and |
| 190 | cache_pc_function_high are used to set outputs as well. */ |
| 191 | |
| 192 | static CORE_ADDR cache_pc_function_low = 0; |
| 193 | static CORE_ADDR cache_pc_function_high = 0; |
| 194 | static const char *cache_pc_function_name = 0; |
| 195 | static struct obj_section *cache_pc_function_section = NULL; |
| 196 | static const struct block *cache_pc_function_block = nullptr; |
| 197 | |
| 198 | /* Clear cache, e.g. when symbol table is discarded. */ |
| 199 | |
| 200 | void |
| 201 | clear_pc_function_cache (void) |
| 202 | { |
| 203 | cache_pc_function_low = 0; |
| 204 | cache_pc_function_high = 0; |
| 205 | cache_pc_function_name = (char *) 0; |
| 206 | cache_pc_function_section = NULL; |
| 207 | cache_pc_function_block = nullptr; |
| 208 | } |
| 209 | |
| 210 | /* See symtab.h. */ |
| 211 | |
| 212 | int |
| 213 | find_pc_partial_function (CORE_ADDR pc, const char **name, CORE_ADDR *address, |
| 214 | CORE_ADDR *endaddr, const struct block **block) |
| 215 | { |
| 216 | struct obj_section *section; |
| 217 | struct symbol *f; |
| 218 | struct bound_minimal_symbol msymbol; |
| 219 | struct compunit_symtab *compunit_symtab = NULL; |
| 220 | CORE_ADDR mapped_pc; |
| 221 | |
| 222 | /* To ensure that the symbol returned belongs to the correct setion |
| 223 | (and that the last [random] symbol from the previous section |
| 224 | isn't returned) try to find the section containing PC. First try |
| 225 | the overlay code (which by default returns NULL); and second try |
| 226 | the normal section code (which almost always succeeds). */ |
| 227 | section = find_pc_overlay (pc); |
| 228 | if (section == NULL) |
| 229 | section = find_pc_section (pc); |
| 230 | |
| 231 | mapped_pc = overlay_mapped_address (pc, section); |
| 232 | |
| 233 | if (mapped_pc >= cache_pc_function_low |
| 234 | && mapped_pc < cache_pc_function_high |
| 235 | && section == cache_pc_function_section) |
| 236 | goto return_cached_value; |
| 237 | |
| 238 | msymbol = lookup_minimal_symbol_by_pc_section (mapped_pc, section); |
| 239 | for (objfile *objfile : current_program_space->objfiles ()) |
| 240 | { |
| 241 | if (objfile->sf) |
| 242 | { |
| 243 | compunit_symtab |
| 244 | = objfile->sf->qf->find_pc_sect_compunit_symtab (objfile, msymbol, |
| 245 | mapped_pc, |
| 246 | section, |
| 247 | 0); |
| 248 | } |
| 249 | if (compunit_symtab != NULL) |
| 250 | break; |
| 251 | } |
| 252 | |
| 253 | if (compunit_symtab != NULL) |
| 254 | { |
| 255 | /* Checking whether the msymbol has a larger value is for the |
| 256 | "pathological" case mentioned in stack.c:find_frame_funname. |
| 257 | |
| 258 | We use BLOCK_ENTRY_PC instead of BLOCK_START_PC for this |
| 259 | comparison because the minimal symbol should refer to the |
| 260 | function's entry pc which is not necessarily the lowest |
| 261 | address of the function. This will happen when the function |
| 262 | has more than one range and the entry pc is not within the |
| 263 | lowest range of addresses. */ |
| 264 | f = find_pc_sect_function (mapped_pc, section); |
| 265 | if (f != NULL |
| 266 | && (msymbol.minsym == NULL |
| 267 | || (BLOCK_ENTRY_PC (SYMBOL_BLOCK_VALUE (f)) |
| 268 | >= BMSYMBOL_VALUE_ADDRESS (msymbol)))) |
| 269 | { |
| 270 | const struct block *b = SYMBOL_BLOCK_VALUE (f); |
| 271 | |
| 272 | cache_pc_function_name = SYMBOL_LINKAGE_NAME (f); |
| 273 | cache_pc_function_section = section; |
| 274 | cache_pc_function_block = b; |
| 275 | |
| 276 | /* For blocks occupying contiguous addresses (i.e. no gaps), |
| 277 | the low and high cache addresses are simply the start |
| 278 | and end of the block. |
| 279 | |
| 280 | For blocks with non-contiguous ranges, we have to search |
| 281 | for the range containing mapped_pc and then use the start |
| 282 | and end of that range. |
| 283 | |
| 284 | This causes the returned *ADDRESS and *ENDADDR values to |
| 285 | be limited to the range in which mapped_pc is found. See |
| 286 | comment preceding declaration of find_pc_partial_function |
| 287 | in symtab.h for more information. */ |
| 288 | |
| 289 | if (BLOCK_CONTIGUOUS_P (b)) |
| 290 | { |
| 291 | cache_pc_function_low = BLOCK_START (b); |
| 292 | cache_pc_function_high = BLOCK_END (b); |
| 293 | } |
| 294 | else |
| 295 | { |
| 296 | int i; |
| 297 | for (i = 0; i < BLOCK_NRANGES (b); i++) |
| 298 | { |
| 299 | if (BLOCK_RANGE_START (b, i) <= mapped_pc |
| 300 | && mapped_pc < BLOCK_RANGE_END (b, i)) |
| 301 | { |
| 302 | cache_pc_function_low = BLOCK_RANGE_START (b, i); |
| 303 | cache_pc_function_high = BLOCK_RANGE_END (b, i); |
| 304 | break; |
| 305 | } |
| 306 | } |
| 307 | /* Above loop should exit via the break. */ |
| 308 | gdb_assert (i < BLOCK_NRANGES (b)); |
| 309 | } |
| 310 | |
| 311 | |
| 312 | goto return_cached_value; |
| 313 | } |
| 314 | } |
| 315 | |
| 316 | /* Not in the normal symbol tables, see if the pc is in a known |
| 317 | section. If it's not, then give up. This ensures that anything |
| 318 | beyond the end of the text seg doesn't appear to be part of the |
| 319 | last function in the text segment. */ |
| 320 | |
| 321 | if (!section) |
| 322 | msymbol.minsym = NULL; |
| 323 | |
| 324 | /* Must be in the minimal symbol table. */ |
| 325 | if (msymbol.minsym == NULL) |
| 326 | { |
| 327 | /* No available symbol. */ |
| 328 | if (name != NULL) |
| 329 | *name = 0; |
| 330 | if (address != NULL) |
| 331 | *address = 0; |
| 332 | if (endaddr != NULL) |
| 333 | *endaddr = 0; |
| 334 | return 0; |
| 335 | } |
| 336 | |
| 337 | cache_pc_function_low = BMSYMBOL_VALUE_ADDRESS (msymbol); |
| 338 | cache_pc_function_name = MSYMBOL_LINKAGE_NAME (msymbol.minsym); |
| 339 | cache_pc_function_section = section; |
| 340 | cache_pc_function_high = minimal_symbol_upper_bound (msymbol); |
| 341 | cache_pc_function_block = nullptr; |
| 342 | |
| 343 | return_cached_value: |
| 344 | |
| 345 | if (address) |
| 346 | { |
| 347 | if (pc_in_unmapped_range (pc, section)) |
| 348 | *address = overlay_unmapped_address (cache_pc_function_low, section); |
| 349 | else |
| 350 | *address = cache_pc_function_low; |
| 351 | } |
| 352 | |
| 353 | if (name) |
| 354 | *name = cache_pc_function_name; |
| 355 | |
| 356 | if (endaddr) |
| 357 | { |
| 358 | if (pc_in_unmapped_range (pc, section)) |
| 359 | { |
| 360 | /* Because the high address is actually beyond the end of |
| 361 | the function (and therefore possibly beyond the end of |
| 362 | the overlay), we must actually convert (high - 1) and |
| 363 | then add one to that. */ |
| 364 | |
| 365 | *endaddr = 1 + overlay_unmapped_address (cache_pc_function_high - 1, |
| 366 | section); |
| 367 | } |
| 368 | else |
| 369 | *endaddr = cache_pc_function_high; |
| 370 | } |
| 371 | |
| 372 | if (block != nullptr) |
| 373 | *block = cache_pc_function_block; |
| 374 | |
| 375 | return 1; |
| 376 | } |
| 377 | |
| 378 | /* See symtab.h. */ |
| 379 | |
| 380 | bool |
| 381 | find_function_entry_range_from_pc (CORE_ADDR pc, const char **name, |
| 382 | CORE_ADDR *address, CORE_ADDR *endaddr) |
| 383 | { |
| 384 | const struct block *block; |
| 385 | bool status = find_pc_partial_function (pc, name, address, endaddr, &block); |
| 386 | |
| 387 | if (status && block != nullptr && !BLOCK_CONTIGUOUS_P (block)) |
| 388 | { |
| 389 | CORE_ADDR entry_pc = BLOCK_ENTRY_PC (block); |
| 390 | |
| 391 | for (int i = 0; i < BLOCK_NRANGES (block); i++) |
| 392 | { |
| 393 | if (BLOCK_RANGE_START (block, i) <= entry_pc |
| 394 | && entry_pc < BLOCK_RANGE_END (block, i)) |
| 395 | { |
| 396 | if (address != nullptr) |
| 397 | *address = BLOCK_RANGE_START (block, i); |
| 398 | |
| 399 | if (endaddr != nullptr) |
| 400 | *endaddr = BLOCK_RANGE_END (block, i); |
| 401 | |
| 402 | return status; |
| 403 | } |
| 404 | } |
| 405 | |
| 406 | /* It's an internal error if we exit the above loop without finding |
| 407 | the range. */ |
| 408 | internal_error (__FILE__, __LINE__, |
| 409 | _("Entry block not found in find_function_entry_range_from_pc")); |
| 410 | } |
| 411 | |
| 412 | return status; |
| 413 | } |
| 414 | |
| 415 | /* See symtab.h. */ |
| 416 | |
| 417 | struct type * |
| 418 | find_function_type (CORE_ADDR pc) |
| 419 | { |
| 420 | struct symbol *sym = find_pc_function (pc); |
| 421 | |
| 422 | if (sym != NULL && BLOCK_ENTRY_PC (SYMBOL_BLOCK_VALUE (sym)) == pc) |
| 423 | return SYMBOL_TYPE (sym); |
| 424 | |
| 425 | return NULL; |
| 426 | } |
| 427 | |
| 428 | /* See symtab.h. */ |
| 429 | |
| 430 | struct type * |
| 431 | find_gnu_ifunc_target_type (CORE_ADDR resolver_funaddr) |
| 432 | { |
| 433 | struct type *resolver_type = find_function_type (resolver_funaddr); |
| 434 | if (resolver_type != NULL) |
| 435 | { |
| 436 | /* Get the return type of the resolver. */ |
| 437 | struct type *resolver_ret_type |
| 438 | = check_typedef (TYPE_TARGET_TYPE (resolver_type)); |
| 439 | |
| 440 | /* If we found a pointer to function, then the resolved type |
| 441 | is the type of the pointed-to function. */ |
| 442 | if (TYPE_CODE (resolver_ret_type) == TYPE_CODE_PTR) |
| 443 | { |
| 444 | struct type *resolved_type |
| 445 | = TYPE_TARGET_TYPE (resolver_ret_type); |
| 446 | if (TYPE_CODE (check_typedef (resolved_type)) == TYPE_CODE_FUNC) |
| 447 | return resolved_type; |
| 448 | } |
| 449 | } |
| 450 | |
| 451 | return NULL; |
| 452 | } |
| 453 | |
| 454 | /* Return the innermost stack frame that is executing inside of BLOCK and is |
| 455 | at least as old as the selected frame. Return NULL if there is no |
| 456 | such frame. If BLOCK is NULL, just return NULL. */ |
| 457 | |
| 458 | struct frame_info * |
| 459 | block_innermost_frame (const struct block *block) |
| 460 | { |
| 461 | struct frame_info *frame; |
| 462 | |
| 463 | if (block == NULL) |
| 464 | return NULL; |
| 465 | |
| 466 | frame = get_selected_frame_if_set (); |
| 467 | if (frame == NULL) |
| 468 | frame = get_current_frame (); |
| 469 | while (frame != NULL) |
| 470 | { |
| 471 | const struct block *frame_block = get_frame_block (frame, NULL); |
| 472 | if (frame_block != NULL && contained_in (frame_block, block)) |
| 473 | return frame; |
| 474 | |
| 475 | frame = get_prev_frame (frame); |
| 476 | } |
| 477 | |
| 478 | return NULL; |
| 479 | } |