| 1 | /* Cache and manage frames for GDB, the GNU debugger. |
| 2 | |
| 3 | Copyright 1986, 1987, 1989, 1991, 1994, 1995, 1996, 1998, 2000, |
| 4 | 2001, 2002, 2003 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 2 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, write to the Free Software |
| 20 | Foundation, Inc., 59 Temple Place - Suite 330, |
| 21 | Boston, MA 02111-1307, USA. */ |
| 22 | |
| 23 | #include "defs.h" |
| 24 | #include "frame.h" |
| 25 | #include "target.h" |
| 26 | #include "value.h" |
| 27 | #include "inferior.h" /* for inferior_ptid */ |
| 28 | #include "regcache.h" |
| 29 | #include "gdb_assert.h" |
| 30 | #include "gdb_string.h" |
| 31 | #include "builtin-regs.h" |
| 32 | #include "gdb_obstack.h" |
| 33 | #include "dummy-frame.h" |
| 34 | #include "sentinel-frame.h" |
| 35 | #include "gdbcore.h" |
| 36 | #include "annotate.h" |
| 37 | #include "language.h" |
| 38 | #include "frame-unwind.h" |
| 39 | #include "frame-base.h" |
| 40 | #include "command.h" |
| 41 | #include "gdbcmd.h" |
| 42 | |
| 43 | /* Flag to control debugging. */ |
| 44 | |
| 45 | static int frame_debug; |
| 46 | |
| 47 | /* Flag to indicate whether backtraces should stop at main. */ |
| 48 | |
| 49 | static int backtrace_below_main; |
| 50 | |
| 51 | /* Return a frame uniq ID that can be used to, later, re-find the |
| 52 | frame. */ |
| 53 | |
| 54 | struct frame_id |
| 55 | get_frame_id (struct frame_info *fi) |
| 56 | { |
| 57 | if (fi == NULL) |
| 58 | { |
| 59 | return null_frame_id; |
| 60 | } |
| 61 | if (!fi->id_p) |
| 62 | { |
| 63 | gdb_assert (!legacy_frame_p (current_gdbarch)); |
| 64 | /* Find THIS frame's ID. */ |
| 65 | fi->unwind->this_id (fi->next, &fi->prologue_cache, &fi->id); |
| 66 | fi->id_p = 1; |
| 67 | /* FIXME: cagney/2002-12-18: Instead of this hack, should only |
| 68 | store the frame ID in PREV_FRAME. Unfortunatly, some |
| 69 | architectures (HP/UX) still reply on EXTRA_FRAME_INFO and, |
| 70 | hence, still poke at the "struct frame_info" object directly. */ |
| 71 | fi->frame = fi->id.base; |
| 72 | } |
| 73 | return frame_id_build (fi->frame, fi->pc); |
| 74 | } |
| 75 | |
| 76 | const struct frame_id null_frame_id; /* All zeros. */ |
| 77 | |
| 78 | struct frame_id |
| 79 | frame_id_build (CORE_ADDR base, CORE_ADDR func_or_pc) |
| 80 | { |
| 81 | struct frame_id id; |
| 82 | id.base = base; |
| 83 | id.pc = func_or_pc; |
| 84 | return id; |
| 85 | } |
| 86 | |
| 87 | int |
| 88 | frame_id_p (struct frame_id l) |
| 89 | { |
| 90 | /* The .func can be NULL but the .base cannot. */ |
| 91 | return (l.base != 0); |
| 92 | } |
| 93 | |
| 94 | int |
| 95 | frame_id_eq (struct frame_id l, struct frame_id r) |
| 96 | { |
| 97 | /* If .base is different, the frames are different. */ |
| 98 | if (l.base != r.base) |
| 99 | return 0; |
| 100 | /* Add a test to check that the frame ID's are for the same function |
| 101 | here. */ |
| 102 | return 1; |
| 103 | } |
| 104 | |
| 105 | int |
| 106 | frame_id_inner (struct frame_id l, struct frame_id r) |
| 107 | { |
| 108 | /* Only return non-zero when strictly inner than. Note that, per |
| 109 | comment in "frame.h", there is some fuzz here. Frameless |
| 110 | functions are not strictly inner than (same .base but different |
| 111 | .func). */ |
| 112 | return INNER_THAN (l.base, r.base); |
| 113 | } |
| 114 | |
| 115 | struct frame_info * |
| 116 | frame_find_by_id (struct frame_id id) |
| 117 | { |
| 118 | struct frame_info *frame; |
| 119 | |
| 120 | /* ZERO denotes the null frame, let the caller decide what to do |
| 121 | about it. Should it instead return get_current_frame()? */ |
| 122 | if (!frame_id_p (id)) |
| 123 | return NULL; |
| 124 | |
| 125 | for (frame = get_current_frame (); |
| 126 | frame != NULL; |
| 127 | frame = get_prev_frame (frame)) |
| 128 | { |
| 129 | struct frame_id this = get_frame_id (frame); |
| 130 | if (frame_id_eq (id, this)) |
| 131 | /* An exact match. */ |
| 132 | return frame; |
| 133 | if (frame_id_inner (id, this)) |
| 134 | /* Gone to far. */ |
| 135 | return NULL; |
| 136 | /* Either, we're not yet gone far enough out along the frame |
| 137 | chain (inner(this,id), or we're comparing frameless functions |
| 138 | (same .base, different .func, no test available). Struggle |
| 139 | on until we've definitly gone to far. */ |
| 140 | } |
| 141 | return NULL; |
| 142 | } |
| 143 | |
| 144 | CORE_ADDR |
| 145 | frame_pc_unwind (struct frame_info *this_frame) |
| 146 | { |
| 147 | if (!this_frame->pc_unwind_cache_p) |
| 148 | { |
| 149 | CORE_ADDR pc; |
| 150 | if (gdbarch_unwind_pc_p (current_gdbarch)) |
| 151 | { |
| 152 | /* The right way. The `pure' way. The one true way. This |
| 153 | method depends solely on the register-unwind code to |
| 154 | determine the value of registers in THIS frame, and hence |
| 155 | the value of this frame's PC (resume address). A typical |
| 156 | implementation is no more than: |
| 157 | |
| 158 | frame_unwind_register (this_frame, ISA_PC_REGNUM, buf); |
| 159 | return extract_address (buf, size of ISA_PC_REGNUM); |
| 160 | |
| 161 | Note: this method is very heavily dependent on a correct |
| 162 | register-unwind implementation, it pays to fix that |
| 163 | method first; this method is frame type agnostic, since |
| 164 | it only deals with register values, it works with any |
| 165 | frame. This is all in stark contrast to the old |
| 166 | FRAME_SAVED_PC which would try to directly handle all the |
| 167 | different ways that a PC could be unwound. */ |
| 168 | pc = gdbarch_unwind_pc (current_gdbarch, this_frame); |
| 169 | } |
| 170 | else if (this_frame->level < 0) |
| 171 | { |
| 172 | /* FIXME: cagney/2003-03-06: Old code and and a sentinel |
| 173 | frame. Do like was always done. Fetch the PC's value |
| 174 | direct from the global registers array (via read_pc). |
| 175 | This assumes that this frame belongs to the current |
| 176 | global register cache. The assumption is dangerous. */ |
| 177 | pc = read_pc (); |
| 178 | } |
| 179 | else if (DEPRECATED_FRAME_SAVED_PC_P ()) |
| 180 | { |
| 181 | /* FIXME: cagney/2003-03-06: Old code, but not a sentinel |
| 182 | frame. Do like was always done. Note that this method, |
| 183 | unlike unwind_pc(), tries to handle all the different |
| 184 | frame cases directly. It fails. */ |
| 185 | pc = DEPRECATED_FRAME_SAVED_PC (this_frame); |
| 186 | } |
| 187 | else |
| 188 | internal_error (__FILE__, __LINE__, "No gdbarch_unwind_pc method"); |
| 189 | this_frame->pc_unwind_cache = pc; |
| 190 | this_frame->pc_unwind_cache_p = 1; |
| 191 | } |
| 192 | return this_frame->pc_unwind_cache; |
| 193 | } |
| 194 | |
| 195 | static int |
| 196 | do_frame_unwind_register (void *src, int regnum, void *buf) |
| 197 | { |
| 198 | frame_unwind_register (src, regnum, buf); |
| 199 | return 1; |
| 200 | } |
| 201 | |
| 202 | void |
| 203 | frame_pop (struct frame_info *this_frame) |
| 204 | { |
| 205 | struct regcache *scratch_regcache; |
| 206 | struct cleanup *cleanups; |
| 207 | |
| 208 | if (DEPRECATED_POP_FRAME_P ()) |
| 209 | { |
| 210 | /* A legacy architecture that has implemented a custom pop |
| 211 | function. All new architectures should instead be using the |
| 212 | generic code below. */ |
| 213 | DEPRECATED_POP_FRAME; |
| 214 | } |
| 215 | else |
| 216 | { |
| 217 | /* Make a copy of all the register values unwound from this |
| 218 | frame. Save them in a scratch buffer so that there isn't a |
| 219 | race betweening trying to extract the old values from the |
| 220 | current_regcache while, at the same time writing new values |
| 221 | into that same cache. */ |
| 222 | struct regcache *scratch = regcache_xmalloc (current_gdbarch); |
| 223 | struct cleanup *cleanups = make_cleanup_regcache_xfree (scratch); |
| 224 | regcache_save (scratch, do_frame_unwind_register, this_frame); |
| 225 | /* FIXME: cagney/2003-03-16: It should be possible to tell the |
| 226 | target's register cache that it is about to be hit with a |
| 227 | burst register transfer and that the sequence of register |
| 228 | writes should be batched. The pair target_prepare_to_store() |
| 229 | and target_store_registers() kind of suggest this |
| 230 | functionality. Unfortunatly, they don't implement it. Their |
| 231 | lack of a formal definition can lead to targets writing back |
| 232 | bogus values (arguably a bug in the target code mind). */ |
| 233 | /* Now copy those saved registers into the current regcache. |
| 234 | Here, regcache_cpy() calls regcache_restore(). */ |
| 235 | regcache_cpy (current_regcache, scratch); |
| 236 | do_cleanups (cleanups); |
| 237 | } |
| 238 | /* We've made right mess of GDB's local state, just discard |
| 239 | everything. */ |
| 240 | flush_cached_frames (); |
| 241 | } |
| 242 | |
| 243 | void |
| 244 | frame_register_unwind (struct frame_info *frame, int regnum, |
| 245 | int *optimizedp, enum lval_type *lvalp, |
| 246 | CORE_ADDR *addrp, int *realnump, void *bufferp) |
| 247 | { |
| 248 | struct frame_unwind_cache *cache; |
| 249 | |
| 250 | /* Require all but BUFFERP to be valid. A NULL BUFFERP indicates |
| 251 | that the value proper does not need to be fetched. */ |
| 252 | gdb_assert (optimizedp != NULL); |
| 253 | gdb_assert (lvalp != NULL); |
| 254 | gdb_assert (addrp != NULL); |
| 255 | gdb_assert (realnump != NULL); |
| 256 | /* gdb_assert (bufferp != NULL); */ |
| 257 | |
| 258 | /* NOTE: cagney/2002-11-27: A program trying to unwind a NULL frame |
| 259 | is broken. There is always a frame. If there, for some reason, |
| 260 | isn't, there is some pretty busted code as it should have |
| 261 | detected the problem before calling here. */ |
| 262 | gdb_assert (frame != NULL); |
| 263 | |
| 264 | /* Ask this frame to unwind its register. See comment in |
| 265 | "frame-unwind.h" for why NEXT frame and this unwind cace are |
| 266 | passed in. */ |
| 267 | frame->unwind->prev_register (frame->next, &frame->prologue_cache, regnum, |
| 268 | optimizedp, lvalp, addrp, realnump, bufferp); |
| 269 | |
| 270 | } |
| 271 | |
| 272 | void |
| 273 | frame_register (struct frame_info *frame, int regnum, |
| 274 | int *optimizedp, enum lval_type *lvalp, |
| 275 | CORE_ADDR *addrp, int *realnump, void *bufferp) |
| 276 | { |
| 277 | /* Require all but BUFFERP to be valid. A NULL BUFFERP indicates |
| 278 | that the value proper does not need to be fetched. */ |
| 279 | gdb_assert (optimizedp != NULL); |
| 280 | gdb_assert (lvalp != NULL); |
| 281 | gdb_assert (addrp != NULL); |
| 282 | gdb_assert (realnump != NULL); |
| 283 | /* gdb_assert (bufferp != NULL); */ |
| 284 | |
| 285 | /* Ulgh! Old code that, for lval_register, sets ADDRP to the offset |
| 286 | of the register in the register cache. It should instead return |
| 287 | the REGNUM corresponding to that register. Translate the . */ |
| 288 | if (DEPRECATED_GET_SAVED_REGISTER_P ()) |
| 289 | { |
| 290 | DEPRECATED_GET_SAVED_REGISTER (bufferp, optimizedp, addrp, frame, |
| 291 | regnum, lvalp); |
| 292 | /* Compute the REALNUM if the caller wants it. */ |
| 293 | if (*lvalp == lval_register) |
| 294 | { |
| 295 | int regnum; |
| 296 | for (regnum = 0; regnum < NUM_REGS + NUM_PSEUDO_REGS; regnum++) |
| 297 | { |
| 298 | if (*addrp == register_offset_hack (current_gdbarch, regnum)) |
| 299 | { |
| 300 | *realnump = regnum; |
| 301 | return; |
| 302 | } |
| 303 | } |
| 304 | internal_error (__FILE__, __LINE__, |
| 305 | "Failed to compute the register number corresponding" |
| 306 | " to 0x%s", paddr_d (*addrp)); |
| 307 | } |
| 308 | *realnump = -1; |
| 309 | return; |
| 310 | } |
| 311 | |
| 312 | /* Obtain the register value by unwinding the register from the next |
| 313 | (more inner frame). */ |
| 314 | gdb_assert (frame != NULL && frame->next != NULL); |
| 315 | frame_register_unwind (frame->next, regnum, optimizedp, lvalp, addrp, |
| 316 | realnump, bufferp); |
| 317 | } |
| 318 | |
| 319 | void |
| 320 | frame_unwind_register (struct frame_info *frame, int regnum, void *buf) |
| 321 | { |
| 322 | int optimized; |
| 323 | CORE_ADDR addr; |
| 324 | int realnum; |
| 325 | enum lval_type lval; |
| 326 | frame_register_unwind (frame, regnum, &optimized, &lval, &addr, |
| 327 | &realnum, buf); |
| 328 | } |
| 329 | |
| 330 | void |
| 331 | frame_unwind_signed_register (struct frame_info *frame, int regnum, |
| 332 | LONGEST *val) |
| 333 | { |
| 334 | void *buf = alloca (MAX_REGISTER_RAW_SIZE); |
| 335 | frame_unwind_register (frame, regnum, buf); |
| 336 | (*val) = extract_signed_integer (buf, REGISTER_VIRTUAL_SIZE (regnum)); |
| 337 | } |
| 338 | |
| 339 | void |
| 340 | frame_unwind_unsigned_register (struct frame_info *frame, int regnum, |
| 341 | ULONGEST *val) |
| 342 | { |
| 343 | void *buf = alloca (MAX_REGISTER_RAW_SIZE); |
| 344 | frame_unwind_register (frame, regnum, buf); |
| 345 | (*val) = extract_unsigned_integer (buf, REGISTER_VIRTUAL_SIZE (regnum)); |
| 346 | } |
| 347 | |
| 348 | void |
| 349 | frame_read_register (struct frame_info *frame, int regnum, void *buf) |
| 350 | { |
| 351 | gdb_assert (frame != NULL && frame->next != NULL); |
| 352 | frame_unwind_register (frame->next, regnum, buf); |
| 353 | } |
| 354 | |
| 355 | void |
| 356 | frame_read_unsigned_register (struct frame_info *frame, int regnum, |
| 357 | ULONGEST *val) |
| 358 | { |
| 359 | /* NOTE: cagney/2002-10-31: There is a bit of dogma here - there is |
| 360 | always a frame. Both this, and the equivalent |
| 361 | frame_read_signed_register() function, can only be called with a |
| 362 | valid frame. If, for some reason, this function is called |
| 363 | without a frame then the problem isn't here, but rather in the |
| 364 | caller. It should of first created a frame and then passed that |
| 365 | in. */ |
| 366 | /* NOTE: cagney/2002-10-31: As a side bar, keep in mind that the |
| 367 | ``current_frame'' should not be treated as a special case. While |
| 368 | ``get_next_frame (current_frame) == NULL'' currently holds, it |
| 369 | should, as far as possible, not be relied upon. In the future, |
| 370 | ``get_next_frame (current_frame)'' may instead simply return a |
| 371 | normal frame object that simply always gets register values from |
| 372 | the register cache. Consequently, frame code should try to avoid |
| 373 | tests like ``if get_next_frame() == NULL'' and instead just rely |
| 374 | on recursive frame calls (like the below code) when manipulating |
| 375 | a frame chain. */ |
| 376 | gdb_assert (frame != NULL && frame->next != NULL); |
| 377 | frame_unwind_unsigned_register (frame->next, regnum, val); |
| 378 | } |
| 379 | |
| 380 | void |
| 381 | frame_read_signed_register (struct frame_info *frame, int regnum, |
| 382 | LONGEST *val) |
| 383 | { |
| 384 | /* See note above in frame_read_unsigned_register(). */ |
| 385 | gdb_assert (frame != NULL && frame->next != NULL); |
| 386 | frame_unwind_signed_register (frame->next, regnum, val); |
| 387 | } |
| 388 | |
| 389 | void |
| 390 | generic_unwind_get_saved_register (char *raw_buffer, |
| 391 | int *optimizedp, |
| 392 | CORE_ADDR *addrp, |
| 393 | struct frame_info *frame, |
| 394 | int regnum, |
| 395 | enum lval_type *lvalp) |
| 396 | { |
| 397 | int optimizedx; |
| 398 | CORE_ADDR addrx; |
| 399 | int realnumx; |
| 400 | enum lval_type lvalx; |
| 401 | |
| 402 | if (!target_has_registers) |
| 403 | error ("No registers."); |
| 404 | |
| 405 | /* Keep things simple, ensure that all the pointers (except valuep) |
| 406 | are non NULL. */ |
| 407 | if (optimizedp == NULL) |
| 408 | optimizedp = &optimizedx; |
| 409 | if (lvalp == NULL) |
| 410 | lvalp = &lvalx; |
| 411 | if (addrp == NULL) |
| 412 | addrp = &addrx; |
| 413 | |
| 414 | gdb_assert (frame != NULL && frame->next != NULL); |
| 415 | frame_register_unwind (frame->next, regnum, optimizedp, lvalp, addrp, |
| 416 | &realnumx, raw_buffer); |
| 417 | } |
| 418 | |
| 419 | /* frame_register_read () |
| 420 | |
| 421 | Find and return the value of REGNUM for the specified stack frame. |
| 422 | The number of bytes copied is REGISTER_RAW_SIZE (REGNUM). |
| 423 | |
| 424 | Returns 0 if the register value could not be found. */ |
| 425 | |
| 426 | int |
| 427 | frame_register_read (struct frame_info *frame, int regnum, void *myaddr) |
| 428 | { |
| 429 | int optimized; |
| 430 | enum lval_type lval; |
| 431 | CORE_ADDR addr; |
| 432 | int realnum; |
| 433 | frame_register (frame, regnum, &optimized, &lval, &addr, &realnum, myaddr); |
| 434 | |
| 435 | /* FIXME: cagney/2002-05-15: This test, is just bogus. |
| 436 | |
| 437 | It indicates that the target failed to supply a value for a |
| 438 | register because it was "not available" at this time. Problem |
| 439 | is, the target still has the register and so get saved_register() |
| 440 | may be returning a value saved on the stack. */ |
| 441 | |
| 442 | if (register_cached (regnum) < 0) |
| 443 | return 0; /* register value not available */ |
| 444 | |
| 445 | return !optimized; |
| 446 | } |
| 447 | |
| 448 | |
| 449 | /* Map between a frame register number and its name. A frame register |
| 450 | space is a superset of the cooked register space --- it also |
| 451 | includes builtin registers. */ |
| 452 | |
| 453 | int |
| 454 | frame_map_name_to_regnum (const char *name, int len) |
| 455 | { |
| 456 | int i; |
| 457 | |
| 458 | if (len < 0) |
| 459 | len = strlen (name); |
| 460 | |
| 461 | /* Search register name space. */ |
| 462 | for (i = 0; i < NUM_REGS + NUM_PSEUDO_REGS; i++) |
| 463 | if (REGISTER_NAME (i) && len == strlen (REGISTER_NAME (i)) |
| 464 | && strncmp (name, REGISTER_NAME (i), len) == 0) |
| 465 | { |
| 466 | return i; |
| 467 | } |
| 468 | |
| 469 | /* Try builtin registers. */ |
| 470 | i = builtin_reg_map_name_to_regnum (name, len); |
| 471 | if (i >= 0) |
| 472 | { |
| 473 | /* A builtin register doesn't fall into the architecture's |
| 474 | register range. */ |
| 475 | gdb_assert (i >= NUM_REGS + NUM_PSEUDO_REGS); |
| 476 | return i; |
| 477 | } |
| 478 | |
| 479 | return -1; |
| 480 | } |
| 481 | |
| 482 | const char * |
| 483 | frame_map_regnum_to_name (int regnum) |
| 484 | { |
| 485 | if (regnum < 0) |
| 486 | return NULL; |
| 487 | if (regnum < NUM_REGS + NUM_PSEUDO_REGS) |
| 488 | return REGISTER_NAME (regnum); |
| 489 | return builtin_reg_map_regnum_to_name (regnum); |
| 490 | } |
| 491 | |
| 492 | /* Create a sentinel frame. */ |
| 493 | |
| 494 | struct frame_info * |
| 495 | create_sentinel_frame (struct regcache *regcache) |
| 496 | { |
| 497 | struct frame_info *frame = FRAME_OBSTACK_ZALLOC (struct frame_info); |
| 498 | frame->type = NORMAL_FRAME; |
| 499 | frame->level = -1; |
| 500 | /* Explicitly initialize the sentinel frame's cache. Provide it |
| 501 | with the underlying regcache. In the future additional |
| 502 | information, such as the frame's thread will be added. */ |
| 503 | frame->prologue_cache = sentinel_frame_cache (regcache); |
| 504 | /* For the moment there is only one sentinel frame implementation. */ |
| 505 | frame->unwind = sentinel_frame_unwind; |
| 506 | /* Link this frame back to itself. The frame is self referential |
| 507 | (the unwound PC is the same as the pc), so make it so. */ |
| 508 | frame->next = frame; |
| 509 | /* Always unwind the PC as part of creating this frame. This |
| 510 | ensures that the frame's PC points at something valid. */ |
| 511 | /* FIXME: cagney/2003-01-10: Problem here. Unwinding a sentinel |
| 512 | frame's PC may require information such as the frame's thread's |
| 513 | stop reason. Is it possible to get to that? */ |
| 514 | frame->pc = frame_pc_unwind (frame); |
| 515 | return frame; |
| 516 | } |
| 517 | |
| 518 | /* Info about the innermost stack frame (contents of FP register) */ |
| 519 | |
| 520 | static struct frame_info *current_frame; |
| 521 | |
| 522 | /* Cache for frame addresses already read by gdb. Valid only while |
| 523 | inferior is stopped. Control variables for the frame cache should |
| 524 | be local to this module. */ |
| 525 | |
| 526 | static struct obstack frame_cache_obstack; |
| 527 | |
| 528 | void * |
| 529 | frame_obstack_zalloc (unsigned long size) |
| 530 | { |
| 531 | void *data = obstack_alloc (&frame_cache_obstack, size); |
| 532 | memset (data, 0, size); |
| 533 | return data; |
| 534 | } |
| 535 | |
| 536 | CORE_ADDR * |
| 537 | frame_saved_regs_zalloc (struct frame_info *fi) |
| 538 | { |
| 539 | fi->saved_regs = (CORE_ADDR *) |
| 540 | frame_obstack_zalloc (SIZEOF_FRAME_SAVED_REGS); |
| 541 | return fi->saved_regs; |
| 542 | } |
| 543 | |
| 544 | CORE_ADDR * |
| 545 | get_frame_saved_regs (struct frame_info *fi) |
| 546 | { |
| 547 | return fi->saved_regs; |
| 548 | } |
| 549 | |
| 550 | /* Return the innermost (currently executing) stack frame. This is |
| 551 | split into two functions. The function unwind_to_current_frame() |
| 552 | is wrapped in catch exceptions so that, even when the unwind of the |
| 553 | sentinel frame fails, the function still returns a stack frame. */ |
| 554 | |
| 555 | static int |
| 556 | unwind_to_current_frame (struct ui_out *ui_out, void *args) |
| 557 | { |
| 558 | struct frame_info *frame = get_prev_frame (args); |
| 559 | /* A sentinel frame can fail to unwind, eg, because it's PC value |
| 560 | lands in somewhere like start. */ |
| 561 | if (frame == NULL) |
| 562 | return 1; |
| 563 | current_frame = frame; |
| 564 | return 0; |
| 565 | } |
| 566 | |
| 567 | struct frame_info * |
| 568 | get_current_frame (void) |
| 569 | { |
| 570 | /* First check, and report, the lack of registers. Having GDB |
| 571 | report "No stack!" or "No memory" when the target doesn't even |
| 572 | have registers is very confusing. Besides, "printcmd.exp" |
| 573 | explicitly checks that ``print $pc'' with no registers prints "No |
| 574 | registers". */ |
| 575 | if (!target_has_registers) |
| 576 | error ("No registers."); |
| 577 | if (!target_has_stack) |
| 578 | error ("No stack."); |
| 579 | if (!target_has_memory) |
| 580 | error ("No memory."); |
| 581 | if (current_frame == NULL) |
| 582 | { |
| 583 | struct frame_info *sentinel_frame = |
| 584 | create_sentinel_frame (current_regcache); |
| 585 | if (catch_exceptions (uiout, unwind_to_current_frame, sentinel_frame, |
| 586 | NULL, RETURN_MASK_ERROR) != 0) |
| 587 | { |
| 588 | /* Oops! Fake a current frame? Is this useful? It has a PC |
| 589 | of zero, for instance. */ |
| 590 | current_frame = sentinel_frame; |
| 591 | } |
| 592 | } |
| 593 | return current_frame; |
| 594 | } |
| 595 | |
| 596 | /* The "selected" stack frame is used by default for local and arg |
| 597 | access. May be zero, for no selected frame. */ |
| 598 | |
| 599 | struct frame_info *deprecated_selected_frame; |
| 600 | |
| 601 | /* Return the selected frame. Always non-null (unless there isn't an |
| 602 | inferior sufficient for creating a frame) in which case an error is |
| 603 | thrown. */ |
| 604 | |
| 605 | struct frame_info * |
| 606 | get_selected_frame (void) |
| 607 | { |
| 608 | if (deprecated_selected_frame == NULL) |
| 609 | /* Hey! Don't trust this. It should really be re-finding the |
| 610 | last selected frame of the currently selected thread. This, |
| 611 | though, is better than nothing. */ |
| 612 | select_frame (get_current_frame ()); |
| 613 | /* There is always a frame. */ |
| 614 | gdb_assert (deprecated_selected_frame != NULL); |
| 615 | return deprecated_selected_frame; |
| 616 | } |
| 617 | |
| 618 | /* Select frame FI (or NULL - to invalidate the current frame). */ |
| 619 | |
| 620 | void |
| 621 | select_frame (struct frame_info *fi) |
| 622 | { |
| 623 | register struct symtab *s; |
| 624 | |
| 625 | deprecated_selected_frame = fi; |
| 626 | /* NOTE: cagney/2002-05-04: FI can be NULL. This occures when the |
| 627 | frame is being invalidated. */ |
| 628 | if (selected_frame_level_changed_hook) |
| 629 | selected_frame_level_changed_hook (frame_relative_level (fi)); |
| 630 | |
| 631 | /* FIXME: kseitz/2002-08-28: It would be nice to call |
| 632 | selected_frame_level_changed_event right here, but due to limitations |
| 633 | in the current interfaces, we would end up flooding UIs with events |
| 634 | because select_frame is used extensively internally. |
| 635 | |
| 636 | Once we have frame-parameterized frame (and frame-related) commands, |
| 637 | the event notification can be moved here, since this function will only |
| 638 | be called when the users selected frame is being changed. */ |
| 639 | |
| 640 | /* Ensure that symbols for this frame are read in. Also, determine the |
| 641 | source language of this frame, and switch to it if desired. */ |
| 642 | if (fi) |
| 643 | { |
| 644 | s = find_pc_symtab (fi->pc); |
| 645 | if (s |
| 646 | && s->language != current_language->la_language |
| 647 | && s->language != language_unknown |
| 648 | && language_mode == language_mode_auto) |
| 649 | { |
| 650 | set_language (s->language); |
| 651 | } |
| 652 | } |
| 653 | } |
| 654 | |
| 655 | /* Return the register saved in the simplistic ``saved_regs'' cache. |
| 656 | If the value isn't here AND a value is needed, try the next inner |
| 657 | most frame. */ |
| 658 | |
| 659 | static void |
| 660 | legacy_saved_regs_prev_register (struct frame_info *next_frame, |
| 661 | void **this_prologue_cache, |
| 662 | int regnum, int *optimizedp, |
| 663 | enum lval_type *lvalp, CORE_ADDR *addrp, |
| 664 | int *realnump, void *bufferp) |
| 665 | { |
| 666 | /* HACK: New code is passed the next frame and this cache. |
| 667 | Unfortunatly, old code expects this frame. Since this is a |
| 668 | backward compatibility hack, cheat by walking one level along the |
| 669 | prologue chain to the frame the old code expects. |
| 670 | |
| 671 | Do not try this at home. Professional driver, closed course. */ |
| 672 | struct frame_info *frame = next_frame->prev; |
| 673 | gdb_assert (frame != NULL); |
| 674 | |
| 675 | /* Only (older) architectures that implement the |
| 676 | DEPRECATED_FRAME_INIT_SAVED_REGS method should be using this |
| 677 | function. */ |
| 678 | gdb_assert (DEPRECATED_FRAME_INIT_SAVED_REGS_P ()); |
| 679 | |
| 680 | /* Load the saved_regs register cache. */ |
| 681 | if (get_frame_saved_regs (frame) == NULL) |
| 682 | DEPRECATED_FRAME_INIT_SAVED_REGS (frame); |
| 683 | |
| 684 | if (get_frame_saved_regs (frame) != NULL |
| 685 | && get_frame_saved_regs (frame)[regnum] != 0) |
| 686 | { |
| 687 | if (regnum == SP_REGNUM) |
| 688 | { |
| 689 | /* SP register treated specially. */ |
| 690 | *optimizedp = 0; |
| 691 | *lvalp = not_lval; |
| 692 | *addrp = 0; |
| 693 | *realnump = -1; |
| 694 | if (bufferp != NULL) |
| 695 | store_address (bufferp, REGISTER_RAW_SIZE (regnum), |
| 696 | get_frame_saved_regs (frame)[regnum]); |
| 697 | } |
| 698 | else |
| 699 | { |
| 700 | /* Any other register is saved in memory, fetch it but cache |
| 701 | a local copy of its value. */ |
| 702 | *optimizedp = 0; |
| 703 | *lvalp = lval_memory; |
| 704 | *addrp = get_frame_saved_regs (frame)[regnum]; |
| 705 | *realnump = -1; |
| 706 | if (bufferp != NULL) |
| 707 | { |
| 708 | #if 1 |
| 709 | /* Save each register value, as it is read in, in a |
| 710 | frame based cache. */ |
| 711 | void **regs = (*this_prologue_cache); |
| 712 | if (regs == NULL) |
| 713 | { |
| 714 | int sizeof_cache = ((NUM_REGS + NUM_PSEUDO_REGS) |
| 715 | * sizeof (void *)); |
| 716 | regs = frame_obstack_zalloc (sizeof_cache); |
| 717 | (*this_prologue_cache) = regs; |
| 718 | } |
| 719 | if (regs[regnum] == NULL) |
| 720 | { |
| 721 | regs[regnum] |
| 722 | = frame_obstack_zalloc (REGISTER_RAW_SIZE (regnum)); |
| 723 | read_memory (get_frame_saved_regs (frame)[regnum], regs[regnum], |
| 724 | REGISTER_RAW_SIZE (regnum)); |
| 725 | } |
| 726 | memcpy (bufferp, regs[regnum], REGISTER_RAW_SIZE (regnum)); |
| 727 | #else |
| 728 | /* Read the value in from memory. */ |
| 729 | read_memory (get_frame_saved_regs (frame)[regnum], bufferp, |
| 730 | REGISTER_RAW_SIZE (regnum)); |
| 731 | #endif |
| 732 | } |
| 733 | } |
| 734 | return; |
| 735 | } |
| 736 | |
| 737 | /* No luck. Assume this and the next frame have the same register |
| 738 | value. Pass the unwind request down the frame chain to the next |
| 739 | frame. Hopefully that frame will find the register's location. */ |
| 740 | frame_register_unwind (next_frame, regnum, optimizedp, lvalp, addrp, |
| 741 | realnump, bufferp); |
| 742 | } |
| 743 | |
| 744 | static void |
| 745 | legacy_saved_regs_this_id (struct frame_info *next_frame, |
| 746 | void **this_prologue_cache, |
| 747 | struct frame_id *id) |
| 748 | { |
| 749 | int fromleaf; |
| 750 | CORE_ADDR base; |
| 751 | CORE_ADDR pc; |
| 752 | |
| 753 | if (frame_relative_level (next_frame) < 0) |
| 754 | { |
| 755 | /* FIXME: cagney/2003-03-14: We've got the extra special case of |
| 756 | unwinding a sentinel frame, the PC of which is pointing at a |
| 757 | stack dummy. Fake up the dummy frame's ID using the same |
| 758 | sequence as is found a traditional unwinder. */ |
| 759 | (*id).base = read_fp (); |
| 760 | (*id).pc = read_pc (); |
| 761 | return; |
| 762 | } |
| 763 | |
| 764 | /* Start out by assuming it's NULL. */ |
| 765 | (*id) = null_frame_id; |
| 766 | |
| 767 | if (frame_relative_level (next_frame) <= 0) |
| 768 | /* FIXME: 2002-11-09: Frameless functions can occure anywhere in |
| 769 | the frame chain, not just the inner most frame! The generic, |
| 770 | per-architecture, frame code should handle this and the below |
| 771 | should simply be removed. */ |
| 772 | fromleaf = FRAMELESS_FUNCTION_INVOCATION (next_frame); |
| 773 | else |
| 774 | fromleaf = 0; |
| 775 | |
| 776 | if (fromleaf) |
| 777 | /* A frameless inner-most frame. The `FP' (which isn't an |
| 778 | architecture frame-pointer register!) of the caller is the same |
| 779 | as the callee. */ |
| 780 | /* FIXME: 2002-11-09: There isn't any reason to special case this |
| 781 | edge condition. Instead the per-architecture code should hande |
| 782 | it locally. */ |
| 783 | base = get_frame_base (next_frame); |
| 784 | else |
| 785 | { |
| 786 | /* Two macros defined in tm.h specify the machine-dependent |
| 787 | actions to be performed here. |
| 788 | |
| 789 | First, get the frame's chain-pointer. |
| 790 | |
| 791 | If that is zero, the frame is the outermost frame or a leaf |
| 792 | called by the outermost frame. This means that if start |
| 793 | calls main without a frame, we'll return 0 (which is fine |
| 794 | anyway). |
| 795 | |
| 796 | Nope; there's a problem. This also returns when the current |
| 797 | routine is a leaf of main. This is unacceptable. We move |
| 798 | this to after the ffi test; I'd rather have backtraces from |
| 799 | start go curfluy than have an abort called from main not show |
| 800 | main. */ |
| 801 | gdb_assert (DEPRECATED_FRAME_CHAIN_P ()); |
| 802 | base = DEPRECATED_FRAME_CHAIN (next_frame); |
| 803 | |
| 804 | if (!frame_chain_valid (base, next_frame)) |
| 805 | return; |
| 806 | } |
| 807 | if (base == 0) |
| 808 | return; |
| 809 | |
| 810 | /* FIXME: cagney/2002-06-08: This should probably return the frame's |
| 811 | function and not the PC (a.k.a. resume address). */ |
| 812 | pc = frame_pc_unwind (next_frame); |
| 813 | id->pc = pc; |
| 814 | id->base = base; |
| 815 | } |
| 816 | |
| 817 | const struct frame_unwind legacy_saved_regs_unwinder = { |
| 818 | legacy_saved_regs_this_id, |
| 819 | legacy_saved_regs_prev_register |
| 820 | }; |
| 821 | const struct frame_unwind *legacy_saved_regs_unwind = &legacy_saved_regs_unwinder; |
| 822 | |
| 823 | |
| 824 | /* Function: deprecated_generic_get_saved_register |
| 825 | Find register number REGNUM relative to FRAME and put its (raw, |
| 826 | target format) contents in *RAW_BUFFER. |
| 827 | |
| 828 | Set *OPTIMIZED if the variable was optimized out (and thus can't be |
| 829 | fetched). Note that this is never set to anything other than zero |
| 830 | in this implementation. |
| 831 | |
| 832 | Set *LVAL to lval_memory, lval_register, or not_lval, depending on |
| 833 | whether the value was fetched from memory, from a register, or in a |
| 834 | strange and non-modifiable way (e.g. a frame pointer which was |
| 835 | calculated rather than fetched). We will use not_lval for values |
| 836 | fetched from generic dummy frames. |
| 837 | |
| 838 | Set *ADDRP to the address, either in memory or as a REGISTER_BYTE |
| 839 | offset into the registers array. If the value is stored in a dummy |
| 840 | frame, set *ADDRP to zero. |
| 841 | |
| 842 | The argument RAW_BUFFER must point to aligned memory. */ |
| 843 | |
| 844 | void |
| 845 | deprecated_generic_get_saved_register (char *raw_buffer, int *optimized, |
| 846 | CORE_ADDR *addrp, |
| 847 | struct frame_info *frame, int regnum, |
| 848 | enum lval_type *lval) |
| 849 | { |
| 850 | if (!target_has_registers) |
| 851 | error ("No registers."); |
| 852 | |
| 853 | gdb_assert (DEPRECATED_FRAME_INIT_SAVED_REGS_P ()); |
| 854 | |
| 855 | /* Normal systems don't optimize out things with register numbers. */ |
| 856 | if (optimized != NULL) |
| 857 | *optimized = 0; |
| 858 | |
| 859 | if (addrp) /* default assumption: not found in memory */ |
| 860 | *addrp = 0; |
| 861 | |
| 862 | /* Note: since the current frame's registers could only have been |
| 863 | saved by frames INTERIOR TO the current frame, we skip examining |
| 864 | the current frame itself: otherwise, we would be getting the |
| 865 | previous frame's registers which were saved by the current frame. */ |
| 866 | |
| 867 | if (frame != NULL) |
| 868 | { |
| 869 | for (frame = get_next_frame (frame); |
| 870 | frame_relative_level (frame) >= 0; |
| 871 | frame = get_next_frame (frame)) |
| 872 | { |
| 873 | if (get_frame_type (frame) == DUMMY_FRAME) |
| 874 | { |
| 875 | if (lval) /* found it in a CALL_DUMMY frame */ |
| 876 | *lval = not_lval; |
| 877 | if (raw_buffer) |
| 878 | /* FIXME: cagney/2002-06-26: This should be via the |
| 879 | gdbarch_register_read() method so that it, on the |
| 880 | fly, constructs either a raw or pseudo register |
| 881 | from the raw register cache. */ |
| 882 | regcache_raw_read |
| 883 | (generic_find_dummy_frame (get_frame_pc (frame), |
| 884 | get_frame_base (frame)), |
| 885 | regnum, raw_buffer); |
| 886 | return; |
| 887 | } |
| 888 | |
| 889 | DEPRECATED_FRAME_INIT_SAVED_REGS (frame); |
| 890 | if (get_frame_saved_regs (frame) != NULL |
| 891 | && get_frame_saved_regs (frame)[regnum] != 0) |
| 892 | { |
| 893 | if (lval) /* found it saved on the stack */ |
| 894 | *lval = lval_memory; |
| 895 | if (regnum == SP_REGNUM) |
| 896 | { |
| 897 | if (raw_buffer) /* SP register treated specially */ |
| 898 | store_address (raw_buffer, REGISTER_RAW_SIZE (regnum), |
| 899 | get_frame_saved_regs (frame)[regnum]); |
| 900 | } |
| 901 | else |
| 902 | { |
| 903 | if (addrp) /* any other register */ |
| 904 | *addrp = get_frame_saved_regs (frame)[regnum]; |
| 905 | if (raw_buffer) |
| 906 | read_memory (get_frame_saved_regs (frame)[regnum], raw_buffer, |
| 907 | REGISTER_RAW_SIZE (regnum)); |
| 908 | } |
| 909 | return; |
| 910 | } |
| 911 | } |
| 912 | } |
| 913 | |
| 914 | /* If we get thru the loop to this point, it means the register was |
| 915 | not saved in any frame. Return the actual live-register value. */ |
| 916 | |
| 917 | if (lval) /* found it in a live register */ |
| 918 | *lval = lval_register; |
| 919 | if (addrp) |
| 920 | *addrp = REGISTER_BYTE (regnum); |
| 921 | if (raw_buffer) |
| 922 | deprecated_read_register_gen (regnum, raw_buffer); |
| 923 | } |
| 924 | |
| 925 | /* Determine the frame's type based on its PC. */ |
| 926 | |
| 927 | static enum frame_type |
| 928 | frame_type_from_pc (CORE_ADDR pc) |
| 929 | { |
| 930 | /* FIXME: cagney/2002-11-24: Can't yet directly call |
| 931 | pc_in_dummy_frame() as some architectures don't set |
| 932 | PC_IN_CALL_DUMMY() to generic_pc_in_call_dummy() (remember the |
| 933 | latter is implemented by simply calling pc_in_dummy_frame). */ |
| 934 | if (DEPRECATED_USE_GENERIC_DUMMY_FRAMES |
| 935 | && DEPRECATED_PC_IN_CALL_DUMMY (pc, 0, 0)) |
| 936 | return DUMMY_FRAME; |
| 937 | else |
| 938 | { |
| 939 | char *name; |
| 940 | find_pc_partial_function (pc, &name, NULL, NULL); |
| 941 | if (PC_IN_SIGTRAMP (pc, name)) |
| 942 | return SIGTRAMP_FRAME; |
| 943 | else |
| 944 | return NORMAL_FRAME; |
| 945 | } |
| 946 | } |
| 947 | |
| 948 | /* Create an arbitrary (i.e. address specified by user) or innermost frame. |
| 949 | Always returns a non-NULL value. */ |
| 950 | |
| 951 | struct frame_info * |
| 952 | create_new_frame (CORE_ADDR addr, CORE_ADDR pc) |
| 953 | { |
| 954 | struct frame_info *fi; |
| 955 | |
| 956 | fi = frame_obstack_zalloc (sizeof (struct frame_info)); |
| 957 | |
| 958 | fi->frame = addr; |
| 959 | fi->pc = pc; |
| 960 | fi->next = create_sentinel_frame (current_regcache); |
| 961 | fi->type = frame_type_from_pc (pc); |
| 962 | |
| 963 | if (DEPRECATED_INIT_EXTRA_FRAME_INFO_P ()) |
| 964 | DEPRECATED_INIT_EXTRA_FRAME_INFO (0, fi); |
| 965 | |
| 966 | /* Select/initialize an unwind function. */ |
| 967 | fi->unwind = frame_unwind_find_by_pc (current_gdbarch, fi->pc); |
| 968 | |
| 969 | return fi; |
| 970 | } |
| 971 | |
| 972 | /* Return the frame that THIS_FRAME calls (NULL if THIS_FRAME is the |
| 973 | innermost frame). Be careful to not fall off the bottom of the |
| 974 | frame chain and onto the sentinel frame. */ |
| 975 | |
| 976 | struct frame_info * |
| 977 | get_next_frame (struct frame_info *this_frame) |
| 978 | { |
| 979 | if (this_frame->level > 0) |
| 980 | return this_frame->next; |
| 981 | else |
| 982 | return NULL; |
| 983 | } |
| 984 | |
| 985 | /* Flush the entire frame cache. */ |
| 986 | |
| 987 | void |
| 988 | flush_cached_frames (void) |
| 989 | { |
| 990 | /* Since we can't really be sure what the first object allocated was */ |
| 991 | obstack_free (&frame_cache_obstack, 0); |
| 992 | obstack_init (&frame_cache_obstack); |
| 993 | |
| 994 | current_frame = NULL; /* Invalidate cache */ |
| 995 | select_frame (NULL); |
| 996 | annotate_frames_invalid (); |
| 997 | } |
| 998 | |
| 999 | /* Flush the frame cache, and start a new one if necessary. */ |
| 1000 | |
| 1001 | void |
| 1002 | reinit_frame_cache (void) |
| 1003 | { |
| 1004 | flush_cached_frames (); |
| 1005 | |
| 1006 | /* FIXME: The inferior_ptid test is wrong if there is a corefile. */ |
| 1007 | if (PIDGET (inferior_ptid) != 0) |
| 1008 | { |
| 1009 | select_frame (get_current_frame ()); |
| 1010 | } |
| 1011 | } |
| 1012 | |
| 1013 | /* Create the previous frame using the deprecated methods |
| 1014 | INIT_EXTRA_INFO, INIT_FRAME_PC and INIT_FRAME_PC_FIRST. */ |
| 1015 | |
| 1016 | static struct frame_info * |
| 1017 | legacy_get_prev_frame (struct frame_info *this_frame) |
| 1018 | { |
| 1019 | CORE_ADDR address = 0; |
| 1020 | struct frame_info *prev; |
| 1021 | int fromleaf; |
| 1022 | |
| 1023 | /* Allocate the new frame but do not wire it in to the frame chain. |
| 1024 | Some (bad) code in INIT_FRAME_EXTRA_INFO tries to look along |
| 1025 | frame->next to pull some fancy tricks (of course such code is, by |
| 1026 | definition, recursive). Try to prevent it. |
| 1027 | |
| 1028 | There is no reason to worry about memory leaks, should the |
| 1029 | remainder of the function fail. The allocated memory will be |
| 1030 | quickly reclaimed when the frame cache is flushed, and the `we've |
| 1031 | been here before' check, in get_prev_frame will stop repeated |
| 1032 | memory allocation calls. */ |
| 1033 | prev = FRAME_OBSTACK_ZALLOC (struct frame_info); |
| 1034 | prev->level = this_frame->level + 1; |
| 1035 | |
| 1036 | /* NOTE: cagney/2002-11-18: Should have been correctly setting the |
| 1037 | frame's type here, before anything else, and not last, at the |
| 1038 | bottom of this function. The various |
| 1039 | DEPRECATED_INIT_EXTRA_FRAME_INFO, DEPRECATED_INIT_FRAME_PC, |
| 1040 | DEPRECATED_INIT_FRAME_PC_FIRST and |
| 1041 | DEPRECATED_FRAME_INIT_SAVED_REGS methods are full of work-arounds |
| 1042 | that handle the frame not being correctly set from the start. |
| 1043 | Unfortunatly those same work-arounds rely on the type defaulting |
| 1044 | to NORMAL_FRAME. Ulgh! The new frame code does not have this |
| 1045 | problem. */ |
| 1046 | prev->type = NORMAL_FRAME; |
| 1047 | |
| 1048 | /* A legacy frame's ID is always computed here. Mark it as valid. */ |
| 1049 | prev->id_p = 1; |
| 1050 | |
| 1051 | /* Handle sentinel frame unwind as a special case. */ |
| 1052 | if (this_frame->level < 0) |
| 1053 | { |
| 1054 | /* Try to unwind the PC. If that doesn't work, assume we've reached |
| 1055 | the oldest frame and simply return. Is there a better sentinal |
| 1056 | value? The unwound PC value is then used to initialize the new |
| 1057 | previous frame's type. |
| 1058 | |
| 1059 | Note that the pc-unwind is intentionally performed before the |
| 1060 | frame chain. This is ok since, for old targets, both |
| 1061 | frame_pc_unwind (nee, DEPRECATED_FRAME_SAVED_PC) and |
| 1062 | DEPRECATED_FRAME_CHAIN()) assume THIS_FRAME's data structures |
| 1063 | have already been initialized (using |
| 1064 | DEPRECATED_INIT_EXTRA_FRAME_INFO) and hence the call order |
| 1065 | doesn't matter. |
| 1066 | |
| 1067 | By unwinding the PC first, it becomes possible to, in the case of |
| 1068 | a dummy frame, avoid also unwinding the frame ID. This is |
| 1069 | because (well ignoring the PPC) a dummy frame can be located |
| 1070 | using THIS_FRAME's frame ID. */ |
| 1071 | |
| 1072 | prev->pc = frame_pc_unwind (this_frame); |
| 1073 | if (prev->pc == 0) |
| 1074 | { |
| 1075 | /* The allocated PREV_FRAME will be reclaimed when the frame |
| 1076 | obstack is next purged. */ |
| 1077 | if (frame_debug) |
| 1078 | fprintf_unfiltered (gdb_stdlog, |
| 1079 | "Outermost frame - unwound PC zero\n"); |
| 1080 | return NULL; |
| 1081 | } |
| 1082 | prev->type = frame_type_from_pc (prev->pc); |
| 1083 | |
| 1084 | /* Set the unwind functions based on that identified PC. */ |
| 1085 | prev->unwind = frame_unwind_find_by_pc (current_gdbarch, prev->pc); |
| 1086 | |
| 1087 | /* Find the prev's frame's ID. */ |
| 1088 | if (prev->type == DUMMY_FRAME |
| 1089 | && gdbarch_unwind_dummy_id_p (current_gdbarch)) |
| 1090 | { |
| 1091 | /* When unwinding a normal frame, the stack structure is |
| 1092 | determined by analyzing the frame's function's code (be |
| 1093 | it using brute force prologue analysis, or the dwarf2 |
| 1094 | CFI). In the case of a dummy frame, that simply isn't |
| 1095 | possible. The The PC is either the program entry point, |
| 1096 | or some random address on the stack. Trying to use that |
| 1097 | PC to apply standard frame ID unwind techniques is just |
| 1098 | asking for trouble. */ |
| 1099 | /* Assume call_function_by_hand(), via SAVE_DUMMY_FRAME_TOS, |
| 1100 | previously saved the dummy frame's ID. Things only work |
| 1101 | if the two return the same value. */ |
| 1102 | gdb_assert (SAVE_DUMMY_FRAME_TOS_P ()); |
| 1103 | /* Use an architecture specific method to extract the prev's |
| 1104 | dummy ID from the next frame. Note that this method uses |
| 1105 | frame_register_unwind to obtain the register values |
| 1106 | needed to determine the dummy frame's ID. */ |
| 1107 | prev->id = gdbarch_unwind_dummy_id (current_gdbarch, this_frame); |
| 1108 | } |
| 1109 | else |
| 1110 | { |
| 1111 | /* We're unwinding a sentinel frame, the PC of which is |
| 1112 | pointing at a stack dummy. Fake up the dummy frame's ID |
| 1113 | using the same sequence as is found a traditional |
| 1114 | unwinder. Once all architectures supply the |
| 1115 | unwind_dummy_id method, this code can go away. */ |
| 1116 | prev->id.base = read_fp (); |
| 1117 | prev->id.pc = read_pc (); |
| 1118 | } |
| 1119 | |
| 1120 | /* Check that the unwound ID is valid. */ |
| 1121 | if (!frame_id_p (prev->id)) |
| 1122 | { |
| 1123 | if (frame_debug) |
| 1124 | fprintf_unfiltered (gdb_stdlog, |
| 1125 | "Outermost legacy sentinel frame - unwound frame ID invalid\n"); |
| 1126 | return NULL; |
| 1127 | } |
| 1128 | |
| 1129 | /* Check that the new frame isn't inner to (younger, below, |
| 1130 | next) the old frame. If that happens the frame unwind is |
| 1131 | going backwards. */ |
| 1132 | /* FIXME: cagney/2003-02-25: Ignore the sentinel frame since |
| 1133 | that doesn't have a valid frame ID. Should instead set the |
| 1134 | sentinel frame's frame ID to a `sentinel'. Leave it until |
| 1135 | after the switch to storing the frame ID, instead of the |
| 1136 | frame base, in the frame object. */ |
| 1137 | |
| 1138 | /* FIXME: cagney/2002-12-18: Instead of this hack, should only |
| 1139 | store the frame ID in PREV_FRAME. Unfortunatly, some |
| 1140 | architectures (HP/UX) still reply on EXTRA_FRAME_INFO and, |
| 1141 | hence, still poke at the "struct frame_info" object directly. */ |
| 1142 | prev->frame = prev->id.base; |
| 1143 | |
| 1144 | /* Link it in. */ |
| 1145 | this_frame->prev = prev; |
| 1146 | prev->next = this_frame; |
| 1147 | |
| 1148 | /* FIXME: cagney/2002-01-19: This call will go away. Instead of |
| 1149 | initializing extra info, all frames will use the frame_cache |
| 1150 | (passed to the unwind functions) to store additional frame |
| 1151 | info. Unfortunatly legacy targets can't use |
| 1152 | legacy_get_prev_frame() to unwind the sentinel frame and, |
| 1153 | consequently, are forced to take this code path and rely on |
| 1154 | the below call to DEPRECATED_INIT_EXTRA_FRAME_INFO to |
| 1155 | initialize the inner-most frame. */ |
| 1156 | if (DEPRECATED_INIT_EXTRA_FRAME_INFO_P ()) |
| 1157 | { |
| 1158 | DEPRECATED_INIT_EXTRA_FRAME_INFO (0, prev); |
| 1159 | } |
| 1160 | return prev; |
| 1161 | } |
| 1162 | |
| 1163 | /* This code only works on normal frames. A sentinel frame, where |
| 1164 | the level is -1, should never reach this code. */ |
| 1165 | gdb_assert (this_frame->level >= 0); |
| 1166 | |
| 1167 | /* On some machines it is possible to call a function without |
| 1168 | setting up a stack frame for it. On these machines, we |
| 1169 | define this macro to take two args; a frameinfo pointer |
| 1170 | identifying a frame and a variable to set or clear if it is |
| 1171 | or isn't leafless. */ |
| 1172 | |
| 1173 | /* Still don't want to worry about this except on the innermost |
| 1174 | frame. This macro will set FROMLEAF if THIS_FRAME is a frameless |
| 1175 | function invocation. */ |
| 1176 | if (this_frame->level == 0) |
| 1177 | /* FIXME: 2002-11-09: Frameless functions can occure anywhere in |
| 1178 | the frame chain, not just the inner most frame! The generic, |
| 1179 | per-architecture, frame code should handle this and the below |
| 1180 | should simply be removed. */ |
| 1181 | fromleaf = FRAMELESS_FUNCTION_INVOCATION (this_frame); |
| 1182 | else |
| 1183 | fromleaf = 0; |
| 1184 | |
| 1185 | if (fromleaf) |
| 1186 | /* A frameless inner-most frame. The `FP' (which isn't an |
| 1187 | architecture frame-pointer register!) of the caller is the same |
| 1188 | as the callee. */ |
| 1189 | /* FIXME: 2002-11-09: There isn't any reason to special case this |
| 1190 | edge condition. Instead the per-architecture code should hande |
| 1191 | it locally. */ |
| 1192 | address = get_frame_base (this_frame); |
| 1193 | else |
| 1194 | { |
| 1195 | /* Two macros defined in tm.h specify the machine-dependent |
| 1196 | actions to be performed here. |
| 1197 | |
| 1198 | First, get the frame's chain-pointer. |
| 1199 | |
| 1200 | If that is zero, the frame is the outermost frame or a leaf |
| 1201 | called by the outermost frame. This means that if start |
| 1202 | calls main without a frame, we'll return 0 (which is fine |
| 1203 | anyway). |
| 1204 | |
| 1205 | Nope; there's a problem. This also returns when the current |
| 1206 | routine is a leaf of main. This is unacceptable. We move |
| 1207 | this to after the ffi test; I'd rather have backtraces from |
| 1208 | start go curfluy than have an abort called from main not show |
| 1209 | main. */ |
| 1210 | gdb_assert (DEPRECATED_FRAME_CHAIN_P ()); |
| 1211 | address = DEPRECATED_FRAME_CHAIN (this_frame); |
| 1212 | |
| 1213 | if (!frame_chain_valid (address, this_frame)) |
| 1214 | return 0; |
| 1215 | } |
| 1216 | if (address == 0) |
| 1217 | return 0; |
| 1218 | |
| 1219 | /* Link in the already allocated prev frame. */ |
| 1220 | this_frame->prev = prev; |
| 1221 | prev->next = this_frame; |
| 1222 | prev->frame = address; |
| 1223 | |
| 1224 | /* This change should not be needed, FIXME! We should determine |
| 1225 | whether any targets *need* DEPRECATED_INIT_FRAME_PC to happen |
| 1226 | after DEPRECATED_INIT_EXTRA_FRAME_INFO and come up with a simple |
| 1227 | way to express what goes on here. |
| 1228 | |
| 1229 | DEPRECATED_INIT_EXTRA_FRAME_INFO is called from two places: |
| 1230 | create_new_frame (where the PC is already set up) and here (where |
| 1231 | it isn't). DEPRECATED_INIT_FRAME_PC is only called from here, |
| 1232 | always after DEPRECATED_INIT_EXTRA_FRAME_INFO. |
| 1233 | |
| 1234 | The catch is the MIPS, where DEPRECATED_INIT_EXTRA_FRAME_INFO |
| 1235 | requires the PC value (which hasn't been set yet). Some other |
| 1236 | machines appear to require DEPRECATED_INIT_EXTRA_FRAME_INFO |
| 1237 | before they can do DEPRECATED_INIT_FRAME_PC. Phoo. |
| 1238 | |
| 1239 | We shouldn't need DEPRECATED_INIT_FRAME_PC_FIRST to add more |
| 1240 | complication to an already overcomplicated part of GDB. |
| 1241 | gnu@cygnus.com, 15Sep92. |
| 1242 | |
| 1243 | Assuming that some machines need DEPRECATED_INIT_FRAME_PC after |
| 1244 | DEPRECATED_INIT_EXTRA_FRAME_INFO, one possible scheme: |
| 1245 | |
| 1246 | SETUP_INNERMOST_FRAME(): Default version is just create_new_frame |
| 1247 | (read_fp ()), read_pc ()). Machines with extra frame info would |
| 1248 | do that (or the local equivalent) and then set the extra fields. |
| 1249 | |
| 1250 | SETUP_ARBITRARY_FRAME(argc, argv): Only change here is that |
| 1251 | create_new_frame would no longer init extra frame info; |
| 1252 | SETUP_ARBITRARY_FRAME would have to do that. |
| 1253 | |
| 1254 | INIT_PREV_FRAME(fromleaf, prev) Replace |
| 1255 | DEPRECATED_INIT_EXTRA_FRAME_INFO and DEPRECATED_INIT_FRAME_PC. |
| 1256 | This should also return a flag saying whether to keep the new |
| 1257 | frame, or whether to discard it, because on some machines (e.g. |
| 1258 | mips) it is really awkward to have DEPRECATED_FRAME_CHAIN_VALID |
| 1259 | called BEFORE DEPRECATED_INIT_EXTRA_FRAME_INFO (there is no good |
| 1260 | way to get information deduced in DEPRECATED_FRAME_CHAIN_VALID |
| 1261 | into the extra fields of the new frame). std_frame_pc(fromleaf, |
| 1262 | prev) |
| 1263 | |
| 1264 | This is the default setting for INIT_PREV_FRAME. It just does |
| 1265 | what the default DEPRECATED_INIT_FRAME_PC does. Some machines |
| 1266 | will call it from INIT_PREV_FRAME (either at the beginning, the |
| 1267 | end, or in the middle). Some machines won't use it. |
| 1268 | |
| 1269 | kingdon@cygnus.com, 13Apr93, 31Jan94, 14Dec94. */ |
| 1270 | |
| 1271 | /* NOTE: cagney/2002-11-09: Just ignore the above! There is no |
| 1272 | reason for things to be this complicated. |
| 1273 | |
| 1274 | The trick is to assume that there is always a frame. Instead of |
| 1275 | special casing the inner-most frame, create fake frame |
| 1276 | (containing the hardware registers) that is inner to the |
| 1277 | user-visible inner-most frame (...) and then unwind from that. |
| 1278 | That way architecture code can use use the standard |
| 1279 | frame_XX_unwind() functions and not differentiate between the |
| 1280 | inner most and any other case. |
| 1281 | |
| 1282 | Since there is always a frame to unwind from, there is always |
| 1283 | somewhere (THIS_FRAME) to store all the info needed to construct |
| 1284 | a new (previous) frame without having to first create it. This |
| 1285 | means that the convolution below - needing to carefully order a |
| 1286 | frame's initialization - isn't needed. |
| 1287 | |
| 1288 | The irony here though, is that DEPRECATED_FRAME_CHAIN(), at least |
| 1289 | for a more up-to-date architecture, always calls |
| 1290 | FRAME_SAVED_PC(), and FRAME_SAVED_PC() computes the PC but |
| 1291 | without first needing the frame! Instead of the convolution |
| 1292 | below, we could have simply called FRAME_SAVED_PC() and been done |
| 1293 | with it! Note that FRAME_SAVED_PC() is being superseed by |
| 1294 | frame_pc_unwind() and that function does have somewhere to cache |
| 1295 | that PC value. */ |
| 1296 | |
| 1297 | if (DEPRECATED_INIT_FRAME_PC_FIRST_P ()) |
| 1298 | prev->pc = (DEPRECATED_INIT_FRAME_PC_FIRST (fromleaf, prev)); |
| 1299 | |
| 1300 | if (DEPRECATED_INIT_EXTRA_FRAME_INFO_P ()) |
| 1301 | DEPRECATED_INIT_EXTRA_FRAME_INFO (fromleaf, prev); |
| 1302 | |
| 1303 | /* This entry is in the frame queue now, which is good since |
| 1304 | FRAME_SAVED_PC may use that queue to figure out its value (see |
| 1305 | tm-sparc.h). We want the pc saved in the inferior frame. */ |
| 1306 | if (DEPRECATED_INIT_FRAME_PC_P ()) |
| 1307 | prev->pc = DEPRECATED_INIT_FRAME_PC (fromleaf, prev); |
| 1308 | |
| 1309 | /* If ->frame and ->pc are unchanged, we are in the process of |
| 1310 | getting ourselves into an infinite backtrace. Some architectures |
| 1311 | check this in DEPRECATED_FRAME_CHAIN or thereabouts, but it seems |
| 1312 | like there is no reason this can't be an architecture-independent |
| 1313 | check. */ |
| 1314 | if (prev->frame == this_frame->frame |
| 1315 | && prev->pc == this_frame->pc) |
| 1316 | { |
| 1317 | this_frame->prev = NULL; |
| 1318 | obstack_free (&frame_cache_obstack, prev); |
| 1319 | return NULL; |
| 1320 | } |
| 1321 | |
| 1322 | /* Initialize the code used to unwind the frame PREV based on the PC |
| 1323 | (and probably other architectural information). The PC lets you |
| 1324 | check things like the debug info at that point (dwarf2cfi?) and |
| 1325 | use that to decide how the frame should be unwound. */ |
| 1326 | prev->unwind = frame_unwind_find_by_pc (current_gdbarch, prev->pc); |
| 1327 | |
| 1328 | /* NOTE: cagney/2002-11-18: The code segments, found in |
| 1329 | create_new_frame and get_prev_frame(), that initializes the |
| 1330 | frames type is subtly different. The latter only updates ->type |
| 1331 | when it encounters a SIGTRAMP_FRAME or DUMMY_FRAME. This stops |
| 1332 | get_prev_frame() overriding the frame's type when the INIT code |
| 1333 | has previously set it. This is really somewhat bogus. The |
| 1334 | initialization, as seen in create_new_frame(), should occur |
| 1335 | before the INIT function has been called. */ |
| 1336 | if (DEPRECATED_USE_GENERIC_DUMMY_FRAMES |
| 1337 | && (DEPRECATED_PC_IN_CALL_DUMMY_P () |
| 1338 | ? DEPRECATED_PC_IN_CALL_DUMMY (prev->pc, 0, 0) |
| 1339 | : pc_in_dummy_frame (prev->pc))) |
| 1340 | prev->type = DUMMY_FRAME; |
| 1341 | else |
| 1342 | { |
| 1343 | /* FIXME: cagney/2002-11-10: This should be moved to before the |
| 1344 | INIT code above so that the INIT code knows what the frame's |
| 1345 | type is (in fact, for a [generic] dummy-frame, the type can |
| 1346 | be set and then the entire initialization can be skipped. |
| 1347 | Unforunatly, its the INIT code that sets the PC (Hmm, catch |
| 1348 | 22). */ |
| 1349 | char *name; |
| 1350 | find_pc_partial_function (prev->pc, &name, NULL, NULL); |
| 1351 | if (PC_IN_SIGTRAMP (prev->pc, name)) |
| 1352 | prev->type = SIGTRAMP_FRAME; |
| 1353 | /* FIXME: cagney/2002-11-11: Leave prev->type alone. Some |
| 1354 | architectures are forcing the frame's type in INIT so we |
| 1355 | don't want to override it here. Remember, NORMAL_FRAME == 0, |
| 1356 | so it all works (just :-/). Once this initialization is |
| 1357 | moved to the start of this function, all this nastness will |
| 1358 | go away. */ |
| 1359 | } |
| 1360 | |
| 1361 | return prev; |
| 1362 | } |
| 1363 | |
| 1364 | /* Return a structure containing various interesting information |
| 1365 | about the frame that called THIS_FRAME. Returns NULL |
| 1366 | if there is no such frame. */ |
| 1367 | |
| 1368 | struct frame_info * |
| 1369 | get_prev_frame (struct frame_info *this_frame) |
| 1370 | { |
| 1371 | struct frame_info *prev_frame; |
| 1372 | |
| 1373 | /* Return the inner-most frame, when the caller passes in NULL. */ |
| 1374 | /* NOTE: cagney/2002-11-09: Not sure how this would happen. The |
| 1375 | caller should have previously obtained a valid frame using |
| 1376 | get_selected_frame() and then called this code - only possibility |
| 1377 | I can think of is code behaving badly. |
| 1378 | |
| 1379 | NOTE: cagney/2003-01-10: Talk about code behaving badly. Check |
| 1380 | block_innermost_frame(). It does the sequence: frame = NULL; |
| 1381 | while (1) { frame = get_prev_frame (frame); .... }. Ulgh! Why |
| 1382 | it couldn't be written better, I don't know. |
| 1383 | |
| 1384 | NOTE: cagney/2003-01-11: I suspect what is happening is |
| 1385 | block_innermost_frame() is, when the target has no state |
| 1386 | (registers, memory, ...), still calling this function. The |
| 1387 | assumption being that this function will return NULL indicating |
| 1388 | that a frame isn't possible, rather than checking that the target |
| 1389 | has state and then calling get_current_frame() and |
| 1390 | get_prev_frame(). This is a guess mind. */ |
| 1391 | if (this_frame == NULL) |
| 1392 | { |
| 1393 | /* NOTE: cagney/2002-11-09: There was a code segment here that |
| 1394 | would error out when CURRENT_FRAME was NULL. The comment |
| 1395 | that went with it made the claim ... |
| 1396 | |
| 1397 | ``This screws value_of_variable, which just wants a nice |
| 1398 | clean NULL return from block_innermost_frame if there are no |
| 1399 | frames. I don't think I've ever seen this message happen |
| 1400 | otherwise. And returning NULL here is a perfectly legitimate |
| 1401 | thing to do.'' |
| 1402 | |
| 1403 | Per the above, this code shouldn't even be called with a NULL |
| 1404 | THIS_FRAME. */ |
| 1405 | return current_frame; |
| 1406 | } |
| 1407 | |
| 1408 | /* There is always a frame. If this assertion fails, suspect that |
| 1409 | something should be calling get_selected_frame() or |
| 1410 | get_current_frame(). */ |
| 1411 | gdb_assert (this_frame != NULL); |
| 1412 | |
| 1413 | if (this_frame->level >= 0 |
| 1414 | && !backtrace_below_main |
| 1415 | && inside_main_func (get_frame_pc (this_frame))) |
| 1416 | /* Don't unwind past main(), bug always unwind the sentinel frame. |
| 1417 | Note, this is done _before_ the frame has been marked as |
| 1418 | previously unwound. That way if the user later decides to |
| 1419 | allow unwinds past main(), that just happens. */ |
| 1420 | { |
| 1421 | if (frame_debug) |
| 1422 | fprintf_unfiltered (gdb_stdlog, |
| 1423 | "Outermost frame - inside main func.\n"); |
| 1424 | return NULL; |
| 1425 | } |
| 1426 | |
| 1427 | /* Only try to do the unwind once. */ |
| 1428 | if (this_frame->prev_p) |
| 1429 | return this_frame->prev; |
| 1430 | this_frame->prev_p = 1; |
| 1431 | |
| 1432 | #if 0 |
| 1433 | /* If we're inside the entry file, it isn't valid. Don't apply this |
| 1434 | test to a dummy frame - dummy frame PC's typically land in the |
| 1435 | entry file. Don't apply this test to the sentinel frame. |
| 1436 | Sentinel frames should always be allowed to unwind. */ |
| 1437 | /* NOTE: drow/2002-12-25: should there be a way to disable this |
| 1438 | check? It assumes a single small entry file, and the way some |
| 1439 | debug readers (e.g. dbxread) figure out which object is the |
| 1440 | entry file is somewhat hokey. */ |
| 1441 | /* NOTE: cagney/2003-01-10: If there is a way of disabling this test |
| 1442 | then it should probably be moved to before the ->prev_p test, |
| 1443 | above. */ |
| 1444 | /* NOTE: vinschen/2003-04-01: Disabled. It turns out that the call to |
| 1445 | inside_entry_file destroys a meaningful backtrace under some |
| 1446 | conditions. E. g. the backtrace tests in the asm-source testcase |
| 1447 | are broken for some targets. In this test the functions are all |
| 1448 | implemented as part of one file and the testcase is not necessarily |
| 1449 | linked with a start file (depending on the target). What happens is, |
| 1450 | that the first frame is printed normaly and following frames are |
| 1451 | treated as being inside the enttry file then. This way, only the |
| 1452 | #0 frame is printed in the backtrace output. */ |
| 1453 | if (this_frame->type != DUMMY_FRAME && this_frame->level >= 0 |
| 1454 | && inside_entry_file (get_frame_pc (this_frame))) |
| 1455 | { |
| 1456 | if (frame_debug) |
| 1457 | fprintf_unfiltered (gdb_stdlog, |
| 1458 | "Outermost frame - inside entry file\n"); |
| 1459 | return NULL; |
| 1460 | } |
| 1461 | #endif |
| 1462 | |
| 1463 | /* If we're already inside the entry function for the main objfile, |
| 1464 | then it isn't valid. Don't apply this test to a dummy frame - |
| 1465 | dummy frame PC's typically land in the entry func. Don't apply |
| 1466 | this test to the sentinel frame. Sentinel frames should always |
| 1467 | be allowed to unwind. */ |
| 1468 | /* NOTE: cagney/2003-02-25: Don't enable until someone has found |
| 1469 | hard evidence that this is needed. */ |
| 1470 | if (0 |
| 1471 | && this_frame->type != DUMMY_FRAME && this_frame->level >= 0 |
| 1472 | && inside_entry_func (get_frame_pc (this_frame))) |
| 1473 | { |
| 1474 | if (frame_debug) |
| 1475 | fprintf_unfiltered (gdb_stdlog, |
| 1476 | "Outermost frame - inside entry func\n"); |
| 1477 | return NULL; |
| 1478 | } |
| 1479 | |
| 1480 | /* If any of the old frame initialization methods are around, use |
| 1481 | the legacy get_prev_frame method. */ |
| 1482 | if (legacy_frame_p (current_gdbarch)) |
| 1483 | { |
| 1484 | prev_frame = legacy_get_prev_frame (this_frame); |
| 1485 | if (frame_debug && prev_frame == NULL) |
| 1486 | fprintf_unfiltered (gdb_stdlog, |
| 1487 | "Outermost frame - legacy_get_prev_frame NULL.\n"); |
| 1488 | return prev_frame; |
| 1489 | } |
| 1490 | |
| 1491 | /* Check that this frame's ID was valid. If it wasn't, don't try to |
| 1492 | unwind to the prev frame. Be careful to not apply this test to |
| 1493 | the sentinel frame. */ |
| 1494 | if (this_frame->level >= 0 && !frame_id_p (get_frame_id (this_frame))) |
| 1495 | { |
| 1496 | if (frame_debug) |
| 1497 | fprintf_filtered (gdb_stdlog, |
| 1498 | "Outermost frame - this ID is NULL\n"); |
| 1499 | return NULL; |
| 1500 | } |
| 1501 | |
| 1502 | /* Check that this frame's ID isn't inner to (younger, below, next) |
| 1503 | the next frame. This happens when frame unwind goes backwards. |
| 1504 | Since the sentinel frame isn't valid, don't apply this if this |
| 1505 | frame is entier the inner-most or sentinel frame. */ |
| 1506 | if (this_frame->level > 0 |
| 1507 | && frame_id_inner (get_frame_id (this_frame), |
| 1508 | get_frame_id (this_frame->next))) |
| 1509 | error ("This frame inner-to next frame (corrupt stack?)"); |
| 1510 | |
| 1511 | /* Check that this and the next frame are different. If they are |
| 1512 | not, there is most likely a stack cycle. As with the inner-than |
| 1513 | test, avoid the inner-most and sentinel frames. */ |
| 1514 | /* FIXME: cagney/2003-03-17: Can't yet enable this this check. The |
| 1515 | frame_id_eq() method doesn't yet use function addresses when |
| 1516 | comparing frame IDs. */ |
| 1517 | if (0 |
| 1518 | && this_frame->level > 0 |
| 1519 | && frame_id_eq (get_frame_id (this_frame), |
| 1520 | get_frame_id (this_frame->next))) |
| 1521 | error ("This frame identical to next frame (corrupt stack?)"); |
| 1522 | |
| 1523 | /* Allocate the new frame but do not wire it in to the frame chain. |
| 1524 | Some (bad) code in INIT_FRAME_EXTRA_INFO tries to look along |
| 1525 | frame->next to pull some fancy tricks (of course such code is, by |
| 1526 | definition, recursive). Try to prevent it. |
| 1527 | |
| 1528 | There is no reason to worry about memory leaks, should the |
| 1529 | remainder of the function fail. The allocated memory will be |
| 1530 | quickly reclaimed when the frame cache is flushed, and the `we've |
| 1531 | been here before' check above will stop repeated memory |
| 1532 | allocation calls. */ |
| 1533 | prev_frame = FRAME_OBSTACK_ZALLOC (struct frame_info); |
| 1534 | prev_frame->level = this_frame->level + 1; |
| 1535 | |
| 1536 | /* Try to unwind the PC. If that doesn't work, assume we've reached |
| 1537 | the oldest frame and simply return. Is there a better sentinal |
| 1538 | value? The unwound PC value is then used to initialize the new |
| 1539 | previous frame's type. |
| 1540 | |
| 1541 | Note that the pc-unwind is intentionally performed before the |
| 1542 | frame chain. This is ok since, for old targets, both |
| 1543 | frame_pc_unwind (nee, FRAME_SAVED_PC) and |
| 1544 | DEPRECATED_FRAME_CHAIN()) assume THIS_FRAME's data structures |
| 1545 | have already been initialized (using |
| 1546 | DEPRECATED_INIT_EXTRA_FRAME_INFO) and hence the call order |
| 1547 | doesn't matter. |
| 1548 | |
| 1549 | By unwinding the PC first, it becomes possible to, in the case of |
| 1550 | a dummy frame, avoid also unwinding the frame ID. This is |
| 1551 | because (well ignoring the PPC) a dummy frame can be located |
| 1552 | using THIS_FRAME's frame ID. */ |
| 1553 | |
| 1554 | prev_frame->pc = frame_pc_unwind (this_frame); |
| 1555 | if (prev_frame->pc == 0) |
| 1556 | { |
| 1557 | /* The allocated PREV_FRAME will be reclaimed when the frame |
| 1558 | obstack is next purged. */ |
| 1559 | if (frame_debug) |
| 1560 | fprintf_unfiltered (gdb_stdlog, |
| 1561 | "Outermost frame - unwound PC zero\n"); |
| 1562 | return NULL; |
| 1563 | } |
| 1564 | prev_frame->type = frame_type_from_pc (prev_frame->pc); |
| 1565 | |
| 1566 | /* Set the unwind functions based on that identified PC. */ |
| 1567 | prev_frame->unwind = frame_unwind_find_by_pc (current_gdbarch, |
| 1568 | prev_frame->pc); |
| 1569 | |
| 1570 | /* The prev's frame's ID is computed by demand in get_frame_id(). */ |
| 1571 | |
| 1572 | /* The unwound frame ID is validate at the start of this function, |
| 1573 | as part of the logic to decide if that frame should be further |
| 1574 | unwound, and not here while the prev frame is being created. |
| 1575 | Doing this makes it possible for the user to examine a frame that |
| 1576 | has an invalid frame ID. |
| 1577 | |
| 1578 | The very old VAX frame_args_address_correct() method noted: [...] |
| 1579 | For the sake of argument, suppose that the stack is somewhat |
| 1580 | trashed (which is one reason that "info frame" exists). So, |
| 1581 | return 0 (indicating we don't know the address of the arglist) if |
| 1582 | we don't know what frame this frame calls. */ |
| 1583 | |
| 1584 | /* Link it in. */ |
| 1585 | this_frame->prev = prev_frame; |
| 1586 | prev_frame->next = this_frame; |
| 1587 | |
| 1588 | return prev_frame; |
| 1589 | } |
| 1590 | |
| 1591 | CORE_ADDR |
| 1592 | get_frame_pc (struct frame_info *frame) |
| 1593 | { |
| 1594 | return frame->pc; |
| 1595 | } |
| 1596 | |
| 1597 | static int |
| 1598 | pc_notcurrent (struct frame_info *frame) |
| 1599 | { |
| 1600 | /* If FRAME is not the innermost frame, that normally means that |
| 1601 | FRAME->pc points at the return instruction (which is *after* the |
| 1602 | call instruction), and we want to get the line containing the |
| 1603 | call (because the call is where the user thinks the program is). |
| 1604 | However, if the next frame is either a SIGTRAMP_FRAME or a |
| 1605 | DUMMY_FRAME, then the next frame will contain a saved interrupt |
| 1606 | PC and such a PC indicates the current (rather than next) |
| 1607 | instruction/line, consequently, for such cases, want to get the |
| 1608 | line containing fi->pc. */ |
| 1609 | struct frame_info *next = get_next_frame (frame); |
| 1610 | int notcurrent = (next != NULL && get_frame_type (next) == NORMAL_FRAME); |
| 1611 | return notcurrent; |
| 1612 | } |
| 1613 | |
| 1614 | void |
| 1615 | find_frame_sal (struct frame_info *frame, struct symtab_and_line *sal) |
| 1616 | { |
| 1617 | (*sal) = find_pc_line (frame->pc, pc_notcurrent (frame)); |
| 1618 | } |
| 1619 | |
| 1620 | /* Per "frame.h", return the ``address'' of the frame. Code should |
| 1621 | really be using get_frame_id(). */ |
| 1622 | CORE_ADDR |
| 1623 | get_frame_base (struct frame_info *fi) |
| 1624 | { |
| 1625 | if (!fi->id_p) |
| 1626 | { |
| 1627 | /* HACK: Force the ID code to (indirectly) initialize the |
| 1628 | ->frame pointer. */ |
| 1629 | get_frame_id (fi); |
| 1630 | } |
| 1631 | return fi->frame; |
| 1632 | } |
| 1633 | |
| 1634 | /* High-level offsets into the frame. Used by the debug info. */ |
| 1635 | |
| 1636 | CORE_ADDR |
| 1637 | get_frame_base_address (struct frame_info *fi) |
| 1638 | { |
| 1639 | if (fi->type != NORMAL_FRAME) |
| 1640 | return 0; |
| 1641 | if (fi->base == NULL) |
| 1642 | fi->base = frame_base_find_by_pc (current_gdbarch, get_frame_pc (fi)); |
| 1643 | /* Sneaky: If the low-level unwind and high-level base code share a |
| 1644 | common unwinder, let them share the prologue cache. */ |
| 1645 | if (fi->base->unwind == fi->unwind) |
| 1646 | return fi->base->this_base (fi->next, &fi->prologue_cache); |
| 1647 | return fi->base->this_base (fi->next, &fi->base_cache); |
| 1648 | } |
| 1649 | |
| 1650 | CORE_ADDR |
| 1651 | get_frame_locals_address (struct frame_info *fi) |
| 1652 | { |
| 1653 | void **cache; |
| 1654 | if (fi->type != NORMAL_FRAME) |
| 1655 | return 0; |
| 1656 | /* If there isn't a frame address method, find it. */ |
| 1657 | if (fi->base == NULL) |
| 1658 | fi->base = frame_base_find_by_pc (current_gdbarch, get_frame_pc (fi)); |
| 1659 | /* Sneaky: If the low-level unwind and high-level base code share a |
| 1660 | common unwinder, let them share the prologue cache. */ |
| 1661 | if (fi->base->unwind == fi->unwind) |
| 1662 | cache = &fi->prologue_cache; |
| 1663 | else |
| 1664 | cache = &fi->base_cache; |
| 1665 | return fi->base->this_locals (fi->next, cache); |
| 1666 | } |
| 1667 | |
| 1668 | CORE_ADDR |
| 1669 | get_frame_args_address (struct frame_info *fi) |
| 1670 | { |
| 1671 | void **cache; |
| 1672 | if (fi->type != NORMAL_FRAME) |
| 1673 | return 0; |
| 1674 | /* If there isn't a frame address method, find it. */ |
| 1675 | if (fi->base == NULL) |
| 1676 | fi->base = frame_base_find_by_pc (current_gdbarch, get_frame_pc (fi)); |
| 1677 | /* Sneaky: If the low-level unwind and high-level base code share a |
| 1678 | common unwinder, let them share the prologue cache. */ |
| 1679 | if (fi->base->unwind == fi->unwind) |
| 1680 | cache = &fi->prologue_cache; |
| 1681 | else |
| 1682 | cache = &fi->base_cache; |
| 1683 | return fi->base->this_args (fi->next, cache); |
| 1684 | } |
| 1685 | |
| 1686 | /* Level of the selected frame: 0 for innermost, 1 for its caller, ... |
| 1687 | or -1 for a NULL frame. */ |
| 1688 | |
| 1689 | int |
| 1690 | frame_relative_level (struct frame_info *fi) |
| 1691 | { |
| 1692 | if (fi == NULL) |
| 1693 | return -1; |
| 1694 | else |
| 1695 | return fi->level; |
| 1696 | } |
| 1697 | |
| 1698 | enum frame_type |
| 1699 | get_frame_type (struct frame_info *frame) |
| 1700 | { |
| 1701 | /* Some targets still don't use [generic] dummy frames. Catch them |
| 1702 | here. */ |
| 1703 | if (!DEPRECATED_USE_GENERIC_DUMMY_FRAMES |
| 1704 | && deprecated_frame_in_dummy (frame)) |
| 1705 | return DUMMY_FRAME; |
| 1706 | return frame->type; |
| 1707 | } |
| 1708 | |
| 1709 | void |
| 1710 | deprecated_set_frame_type (struct frame_info *frame, enum frame_type type) |
| 1711 | { |
| 1712 | /* Arrrg! See comment in "frame.h". */ |
| 1713 | frame->type = type; |
| 1714 | } |
| 1715 | |
| 1716 | #ifdef FRAME_FIND_SAVED_REGS |
| 1717 | /* XXX - deprecated. This is a compatibility function for targets |
| 1718 | that do not yet implement DEPRECATED_FRAME_INIT_SAVED_REGS. */ |
| 1719 | /* Find the addresses in which registers are saved in FRAME. */ |
| 1720 | |
| 1721 | void |
| 1722 | deprecated_get_frame_saved_regs (struct frame_info *frame, |
| 1723 | struct frame_saved_regs *saved_regs_addr) |
| 1724 | { |
| 1725 | if (frame->saved_regs == NULL) |
| 1726 | { |
| 1727 | frame->saved_regs = (CORE_ADDR *) |
| 1728 | frame_obstack_zalloc (SIZEOF_FRAME_SAVED_REGS); |
| 1729 | } |
| 1730 | if (saved_regs_addr == NULL) |
| 1731 | { |
| 1732 | struct frame_saved_regs saved_regs; |
| 1733 | FRAME_FIND_SAVED_REGS (frame, saved_regs); |
| 1734 | memcpy (frame->saved_regs, &saved_regs, SIZEOF_FRAME_SAVED_REGS); |
| 1735 | } |
| 1736 | else |
| 1737 | { |
| 1738 | FRAME_FIND_SAVED_REGS (frame, *saved_regs_addr); |
| 1739 | memcpy (frame->saved_regs, saved_regs_addr, SIZEOF_FRAME_SAVED_REGS); |
| 1740 | } |
| 1741 | } |
| 1742 | #endif |
| 1743 | |
| 1744 | struct frame_extra_info * |
| 1745 | get_frame_extra_info (struct frame_info *fi) |
| 1746 | { |
| 1747 | return fi->extra_info; |
| 1748 | } |
| 1749 | |
| 1750 | struct frame_extra_info * |
| 1751 | frame_extra_info_zalloc (struct frame_info *fi, long size) |
| 1752 | { |
| 1753 | fi->extra_info = frame_obstack_zalloc (size); |
| 1754 | return fi->extra_info; |
| 1755 | } |
| 1756 | |
| 1757 | void |
| 1758 | deprecated_update_frame_pc_hack (struct frame_info *frame, CORE_ADDR pc) |
| 1759 | { |
| 1760 | /* See comment in "frame.h". */ |
| 1761 | frame->pc = pc; |
| 1762 | /* NOTE: cagney/2003-03-11: Some architectures (e.g., Arm) are |
| 1763 | maintaining a locally allocated frame object. Since such frame's |
| 1764 | are not in the frame chain, it isn't possible to assume that the |
| 1765 | frame has a next. Sigh. */ |
| 1766 | if (frame->next != NULL) |
| 1767 | { |
| 1768 | /* While we're at it, update this frame's cached PC value, found |
| 1769 | in the next frame. Oh for the day when "struct frame_info" |
| 1770 | is opaque and this hack on hack can just go away. */ |
| 1771 | frame->next->pc_unwind_cache = pc; |
| 1772 | frame->next->pc_unwind_cache_p = 1; |
| 1773 | } |
| 1774 | } |
| 1775 | |
| 1776 | void |
| 1777 | deprecated_update_frame_base_hack (struct frame_info *frame, CORE_ADDR base) |
| 1778 | { |
| 1779 | /* See comment in "frame.h". */ |
| 1780 | frame->frame = base; |
| 1781 | } |
| 1782 | |
| 1783 | void |
| 1784 | deprecated_set_frame_saved_regs_hack (struct frame_info *frame, |
| 1785 | CORE_ADDR *saved_regs) |
| 1786 | { |
| 1787 | frame->saved_regs = saved_regs; |
| 1788 | } |
| 1789 | |
| 1790 | void |
| 1791 | deprecated_set_frame_extra_info_hack (struct frame_info *frame, |
| 1792 | struct frame_extra_info *extra_info) |
| 1793 | { |
| 1794 | frame->extra_info = extra_info; |
| 1795 | } |
| 1796 | |
| 1797 | void |
| 1798 | deprecated_set_frame_next_hack (struct frame_info *fi, |
| 1799 | struct frame_info *next) |
| 1800 | { |
| 1801 | fi->next = next; |
| 1802 | } |
| 1803 | |
| 1804 | void |
| 1805 | deprecated_set_frame_prev_hack (struct frame_info *fi, |
| 1806 | struct frame_info *prev) |
| 1807 | { |
| 1808 | fi->prev = prev; |
| 1809 | } |
| 1810 | |
| 1811 | struct context * |
| 1812 | deprecated_get_frame_context (struct frame_info *fi) |
| 1813 | { |
| 1814 | return fi->context; |
| 1815 | } |
| 1816 | |
| 1817 | void |
| 1818 | deprecated_set_frame_context (struct frame_info *fi, |
| 1819 | struct context *context) |
| 1820 | { |
| 1821 | fi->context = context; |
| 1822 | } |
| 1823 | |
| 1824 | struct frame_info * |
| 1825 | deprecated_frame_xmalloc (void) |
| 1826 | { |
| 1827 | struct frame_info *frame = XMALLOC (struct frame_info); |
| 1828 | memset (frame, 0, sizeof (struct frame_info)); |
| 1829 | return frame; |
| 1830 | } |
| 1831 | |
| 1832 | struct frame_info * |
| 1833 | deprecated_frame_xmalloc_with_cleanup (long sizeof_saved_regs, |
| 1834 | long sizeof_extra_info) |
| 1835 | { |
| 1836 | struct frame_info *frame = deprecated_frame_xmalloc (); |
| 1837 | make_cleanup (xfree, frame); |
| 1838 | if (sizeof_saved_regs > 0) |
| 1839 | { |
| 1840 | frame->saved_regs = xcalloc (1, sizeof_saved_regs); |
| 1841 | make_cleanup (xfree, frame->saved_regs); |
| 1842 | } |
| 1843 | if (sizeof_extra_info > 0) |
| 1844 | { |
| 1845 | frame->extra_info = xcalloc (1, sizeof_extra_info); |
| 1846 | make_cleanup (xfree, frame->extra_info); |
| 1847 | } |
| 1848 | return frame; |
| 1849 | } |
| 1850 | |
| 1851 | int |
| 1852 | legacy_frame_p (struct gdbarch *current_gdbarch) |
| 1853 | { |
| 1854 | return (DEPRECATED_INIT_FRAME_PC_P () |
| 1855 | || DEPRECATED_INIT_FRAME_PC_FIRST_P () |
| 1856 | || DEPRECATED_INIT_EXTRA_FRAME_INFO_P () |
| 1857 | || DEPRECATED_FRAME_CHAIN_P () |
| 1858 | || !gdbarch_unwind_dummy_id_p (current_gdbarch) |
| 1859 | || !SAVE_DUMMY_FRAME_TOS_P ()); |
| 1860 | } |
| 1861 | |
| 1862 | void |
| 1863 | _initialize_frame (void) |
| 1864 | { |
| 1865 | obstack_init (&frame_cache_obstack); |
| 1866 | |
| 1867 | /* FIXME: cagney/2003-01-19: This command needs a rename. Suggest |
| 1868 | `set backtrace {past,beyond,...}-main'. Also suggest adding `set |
| 1869 | backtrace ...-start' to control backtraces past start. The |
| 1870 | problem with `below' is that it stops the `up' command. */ |
| 1871 | |
| 1872 | add_setshow_boolean_cmd ("backtrace-below-main", class_obscure, |
| 1873 | &backtrace_below_main, "\ |
| 1874 | Set whether backtraces should continue past \"main\".\n\ |
| 1875 | Normally the caller of \"main\" is not of interest, so GDB will terminate\n\ |
| 1876 | the backtrace at \"main\". Set this variable if you need to see the rest\n\ |
| 1877 | of the stack trace.", "\ |
| 1878 | Show whether backtraces should continue past \"main\".\n\ |
| 1879 | Normally the caller of \"main\" is not of interest, so GDB will terminate\n\ |
| 1880 | the backtrace at \"main\". Set this variable if you need to see the rest\n\ |
| 1881 | of the stack trace.", |
| 1882 | NULL, NULL, &setlist, &showlist); |
| 1883 | |
| 1884 | |
| 1885 | /* Debug this files internals. */ |
| 1886 | add_show_from_set (add_set_cmd ("frame", class_maintenance, var_zinteger, |
| 1887 | &frame_debug, "Set frame debugging.\n\ |
| 1888 | When non-zero, frame specific internal debugging is enabled.", &setdebuglist), |
| 1889 | &showdebuglist); |
| 1890 | } |