| 1 | /* Cache and manage frames for GDB, the GNU debugger. |
| 2 | |
| 3 | Copyright (C) 1986, 1987, 1989, 1991, 1994, 1995, 1996, 1998, 2000, 2001, |
| 4 | 2002, 2003, 2004, 2007, 2008 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 "frame.h" |
| 23 | #include "target.h" |
| 24 | #include "value.h" |
| 25 | #include "inferior.h" /* for inferior_ptid */ |
| 26 | #include "regcache.h" |
| 27 | #include "gdb_assert.h" |
| 28 | #include "gdb_string.h" |
| 29 | #include "user-regs.h" |
| 30 | #include "gdb_obstack.h" |
| 31 | #include "dummy-frame.h" |
| 32 | #include "sentinel-frame.h" |
| 33 | #include "gdbcore.h" |
| 34 | #include "annotate.h" |
| 35 | #include "language.h" |
| 36 | #include "frame-unwind.h" |
| 37 | #include "frame-base.h" |
| 38 | #include "command.h" |
| 39 | #include "gdbcmd.h" |
| 40 | #include "observer.h" |
| 41 | #include "objfiles.h" |
| 42 | #include "exceptions.h" |
| 43 | #include "gdbthread.h" |
| 44 | |
| 45 | static struct frame_info *get_prev_frame_1 (struct frame_info *this_frame); |
| 46 | |
| 47 | /* We keep a cache of stack frames, each of which is a "struct |
| 48 | frame_info". The innermost one gets allocated (in |
| 49 | wait_for_inferior) each time the inferior stops; current_frame |
| 50 | points to it. Additional frames get allocated (in get_prev_frame) |
| 51 | as needed, and are chained through the next and prev fields. Any |
| 52 | time that the frame cache becomes invalid (most notably when we |
| 53 | execute something, but also if we change how we interpret the |
| 54 | frames (e.g. "set heuristic-fence-post" in mips-tdep.c, or anything |
| 55 | which reads new symbols)), we should call reinit_frame_cache. */ |
| 56 | |
| 57 | struct frame_info |
| 58 | { |
| 59 | /* Level of this frame. The inner-most (youngest) frame is at level |
| 60 | 0. As you move towards the outer-most (oldest) frame, the level |
| 61 | increases. This is a cached value. It could just as easily be |
| 62 | computed by counting back from the selected frame to the inner |
| 63 | most frame. */ |
| 64 | /* NOTE: cagney/2002-04-05: Perhaps a level of ``-1'' should be |
| 65 | reserved to indicate a bogus frame - one that has been created |
| 66 | just to keep GDB happy (GDB always needs a frame). For the |
| 67 | moment leave this as speculation. */ |
| 68 | int level; |
| 69 | |
| 70 | /* The frame's low-level unwinder and corresponding cache. The |
| 71 | low-level unwinder is responsible for unwinding register values |
| 72 | for the previous frame. The low-level unwind methods are |
| 73 | selected based on the presence, or otherwise, of register unwind |
| 74 | information such as CFI. */ |
| 75 | void *prologue_cache; |
| 76 | const struct frame_unwind *unwind; |
| 77 | |
| 78 | /* Cached copy of the previous frame's resume address. */ |
| 79 | struct { |
| 80 | int p; |
| 81 | CORE_ADDR value; |
| 82 | } prev_pc; |
| 83 | |
| 84 | /* Cached copy of the previous frame's function address. */ |
| 85 | struct |
| 86 | { |
| 87 | CORE_ADDR addr; |
| 88 | int p; |
| 89 | } prev_func; |
| 90 | |
| 91 | /* This frame's ID. */ |
| 92 | struct |
| 93 | { |
| 94 | int p; |
| 95 | struct frame_id value; |
| 96 | } this_id; |
| 97 | |
| 98 | /* The frame's high-level base methods, and corresponding cache. |
| 99 | The high level base methods are selected based on the frame's |
| 100 | debug info. */ |
| 101 | const struct frame_base *base; |
| 102 | void *base_cache; |
| 103 | |
| 104 | /* Pointers to the next (down, inner, younger) and previous (up, |
| 105 | outer, older) frame_info's in the frame cache. */ |
| 106 | struct frame_info *next; /* down, inner, younger */ |
| 107 | int prev_p; |
| 108 | struct frame_info *prev; /* up, outer, older */ |
| 109 | |
| 110 | /* The reason why we could not set PREV, or UNWIND_NO_REASON if we |
| 111 | could. Only valid when PREV_P is set. */ |
| 112 | enum unwind_stop_reason stop_reason; |
| 113 | }; |
| 114 | |
| 115 | /* Flag to control debugging. */ |
| 116 | |
| 117 | int frame_debug; |
| 118 | static void |
| 119 | show_frame_debug (struct ui_file *file, int from_tty, |
| 120 | struct cmd_list_element *c, const char *value) |
| 121 | { |
| 122 | fprintf_filtered (file, _("Frame debugging is %s.\n"), value); |
| 123 | } |
| 124 | |
| 125 | /* Flag to indicate whether backtraces should stop at main et.al. */ |
| 126 | |
| 127 | static int backtrace_past_main; |
| 128 | static void |
| 129 | show_backtrace_past_main (struct ui_file *file, int from_tty, |
| 130 | struct cmd_list_element *c, const char *value) |
| 131 | { |
| 132 | fprintf_filtered (file, _("\ |
| 133 | Whether backtraces should continue past \"main\" is %s.\n"), |
| 134 | value); |
| 135 | } |
| 136 | |
| 137 | static int backtrace_past_entry; |
| 138 | static void |
| 139 | show_backtrace_past_entry (struct ui_file *file, int from_tty, |
| 140 | struct cmd_list_element *c, const char *value) |
| 141 | { |
| 142 | fprintf_filtered (file, _("\ |
| 143 | Whether backtraces should continue past the entry point of a program is %s.\n"), |
| 144 | value); |
| 145 | } |
| 146 | |
| 147 | static int backtrace_limit = INT_MAX; |
| 148 | static void |
| 149 | show_backtrace_limit (struct ui_file *file, int from_tty, |
| 150 | struct cmd_list_element *c, const char *value) |
| 151 | { |
| 152 | fprintf_filtered (file, _("\ |
| 153 | An upper bound on the number of backtrace levels is %s.\n"), |
| 154 | value); |
| 155 | } |
| 156 | |
| 157 | |
| 158 | static void |
| 159 | fprint_field (struct ui_file *file, const char *name, int p, CORE_ADDR addr) |
| 160 | { |
| 161 | if (p) |
| 162 | fprintf_unfiltered (file, "%s=0x%s", name, paddr_nz (addr)); |
| 163 | else |
| 164 | fprintf_unfiltered (file, "!%s", name); |
| 165 | } |
| 166 | |
| 167 | void |
| 168 | fprint_frame_id (struct ui_file *file, struct frame_id id) |
| 169 | { |
| 170 | fprintf_unfiltered (file, "{"); |
| 171 | fprint_field (file, "stack", id.stack_addr_p, id.stack_addr); |
| 172 | fprintf_unfiltered (file, ","); |
| 173 | fprint_field (file, "code", id.code_addr_p, id.code_addr); |
| 174 | fprintf_unfiltered (file, ","); |
| 175 | fprint_field (file, "special", id.special_addr_p, id.special_addr); |
| 176 | fprintf_unfiltered (file, "}"); |
| 177 | } |
| 178 | |
| 179 | static void |
| 180 | fprint_frame_type (struct ui_file *file, enum frame_type type) |
| 181 | { |
| 182 | switch (type) |
| 183 | { |
| 184 | case NORMAL_FRAME: |
| 185 | fprintf_unfiltered (file, "NORMAL_FRAME"); |
| 186 | return; |
| 187 | case DUMMY_FRAME: |
| 188 | fprintf_unfiltered (file, "DUMMY_FRAME"); |
| 189 | return; |
| 190 | case SIGTRAMP_FRAME: |
| 191 | fprintf_unfiltered (file, "SIGTRAMP_FRAME"); |
| 192 | return; |
| 193 | default: |
| 194 | fprintf_unfiltered (file, "<unknown type>"); |
| 195 | return; |
| 196 | }; |
| 197 | } |
| 198 | |
| 199 | static void |
| 200 | fprint_frame (struct ui_file *file, struct frame_info *fi) |
| 201 | { |
| 202 | if (fi == NULL) |
| 203 | { |
| 204 | fprintf_unfiltered (file, "<NULL frame>"); |
| 205 | return; |
| 206 | } |
| 207 | fprintf_unfiltered (file, "{"); |
| 208 | fprintf_unfiltered (file, "level=%d", fi->level); |
| 209 | fprintf_unfiltered (file, ","); |
| 210 | fprintf_unfiltered (file, "type="); |
| 211 | if (fi->unwind != NULL) |
| 212 | fprint_frame_type (file, fi->unwind->type); |
| 213 | else |
| 214 | fprintf_unfiltered (file, "<unknown>"); |
| 215 | fprintf_unfiltered (file, ","); |
| 216 | fprintf_unfiltered (file, "unwind="); |
| 217 | if (fi->unwind != NULL) |
| 218 | gdb_print_host_address (fi->unwind, file); |
| 219 | else |
| 220 | fprintf_unfiltered (file, "<unknown>"); |
| 221 | fprintf_unfiltered (file, ","); |
| 222 | fprintf_unfiltered (file, "pc="); |
| 223 | if (fi->next != NULL && fi->next->prev_pc.p) |
| 224 | fprintf_unfiltered (file, "0x%s", paddr_nz (fi->next->prev_pc.value)); |
| 225 | else |
| 226 | fprintf_unfiltered (file, "<unknown>"); |
| 227 | fprintf_unfiltered (file, ","); |
| 228 | fprintf_unfiltered (file, "id="); |
| 229 | if (fi->this_id.p) |
| 230 | fprint_frame_id (file, fi->this_id.value); |
| 231 | else |
| 232 | fprintf_unfiltered (file, "<unknown>"); |
| 233 | fprintf_unfiltered (file, ","); |
| 234 | fprintf_unfiltered (file, "func="); |
| 235 | if (fi->next != NULL && fi->next->prev_func.p) |
| 236 | fprintf_unfiltered (file, "0x%s", paddr_nz (fi->next->prev_func.addr)); |
| 237 | else |
| 238 | fprintf_unfiltered (file, "<unknown>"); |
| 239 | fprintf_unfiltered (file, "}"); |
| 240 | } |
| 241 | |
| 242 | /* Return a frame uniq ID that can be used to, later, re-find the |
| 243 | frame. */ |
| 244 | |
| 245 | struct frame_id |
| 246 | get_frame_id (struct frame_info *fi) |
| 247 | { |
| 248 | if (fi == NULL) |
| 249 | { |
| 250 | return null_frame_id; |
| 251 | } |
| 252 | if (!fi->this_id.p) |
| 253 | { |
| 254 | if (frame_debug) |
| 255 | fprintf_unfiltered (gdb_stdlog, "{ get_frame_id (fi=%d) ", |
| 256 | fi->level); |
| 257 | /* Find the unwinder. */ |
| 258 | if (fi->unwind == NULL) |
| 259 | fi->unwind = frame_unwind_find_by_frame (fi, &fi->prologue_cache); |
| 260 | /* Find THIS frame's ID. */ |
| 261 | fi->unwind->this_id (fi, &fi->prologue_cache, &fi->this_id.value); |
| 262 | fi->this_id.p = 1; |
| 263 | if (frame_debug) |
| 264 | { |
| 265 | fprintf_unfiltered (gdb_stdlog, "-> "); |
| 266 | fprint_frame_id (gdb_stdlog, fi->this_id.value); |
| 267 | fprintf_unfiltered (gdb_stdlog, " }\n"); |
| 268 | } |
| 269 | } |
| 270 | return fi->this_id.value; |
| 271 | } |
| 272 | |
| 273 | struct frame_id |
| 274 | frame_unwind_id (struct frame_info *next_frame) |
| 275 | { |
| 276 | /* Use prev_frame, and not get_prev_frame. The latter will truncate |
| 277 | the frame chain, leading to this function unintentionally |
| 278 | returning a null_frame_id (e.g., when a caller requests the frame |
| 279 | ID of "main()"s caller. */ |
| 280 | return get_frame_id (get_prev_frame_1 (next_frame)); |
| 281 | } |
| 282 | |
| 283 | const struct frame_id null_frame_id; /* All zeros. */ |
| 284 | |
| 285 | struct frame_id |
| 286 | frame_id_build_special (CORE_ADDR stack_addr, CORE_ADDR code_addr, |
| 287 | CORE_ADDR special_addr) |
| 288 | { |
| 289 | struct frame_id id = null_frame_id; |
| 290 | id.stack_addr = stack_addr; |
| 291 | id.stack_addr_p = 1; |
| 292 | id.code_addr = code_addr; |
| 293 | id.code_addr_p = 1; |
| 294 | id.special_addr = special_addr; |
| 295 | id.special_addr_p = 1; |
| 296 | return id; |
| 297 | } |
| 298 | |
| 299 | struct frame_id |
| 300 | frame_id_build (CORE_ADDR stack_addr, CORE_ADDR code_addr) |
| 301 | { |
| 302 | struct frame_id id = null_frame_id; |
| 303 | id.stack_addr = stack_addr; |
| 304 | id.stack_addr_p = 1; |
| 305 | id.code_addr = code_addr; |
| 306 | id.code_addr_p = 1; |
| 307 | return id; |
| 308 | } |
| 309 | |
| 310 | struct frame_id |
| 311 | frame_id_build_wild (CORE_ADDR stack_addr) |
| 312 | { |
| 313 | struct frame_id id = null_frame_id; |
| 314 | id.stack_addr = stack_addr; |
| 315 | id.stack_addr_p = 1; |
| 316 | return id; |
| 317 | } |
| 318 | |
| 319 | int |
| 320 | frame_id_p (struct frame_id l) |
| 321 | { |
| 322 | int p; |
| 323 | /* The frame is valid iff it has a valid stack address. */ |
| 324 | p = l.stack_addr_p; |
| 325 | if (frame_debug) |
| 326 | { |
| 327 | fprintf_unfiltered (gdb_stdlog, "{ frame_id_p (l="); |
| 328 | fprint_frame_id (gdb_stdlog, l); |
| 329 | fprintf_unfiltered (gdb_stdlog, ") -> %d }\n", p); |
| 330 | } |
| 331 | return p; |
| 332 | } |
| 333 | |
| 334 | int |
| 335 | frame_id_eq (struct frame_id l, struct frame_id r) |
| 336 | { |
| 337 | int eq; |
| 338 | if (!l.stack_addr_p || !r.stack_addr_p) |
| 339 | /* Like a NaN, if either ID is invalid, the result is false. |
| 340 | Note that a frame ID is invalid iff it is the null frame ID. */ |
| 341 | eq = 0; |
| 342 | else if (l.stack_addr != r.stack_addr) |
| 343 | /* If .stack addresses are different, the frames are different. */ |
| 344 | eq = 0; |
| 345 | else if (!l.code_addr_p || !r.code_addr_p) |
| 346 | /* An invalid code addr is a wild card, always succeed. */ |
| 347 | eq = 1; |
| 348 | else if (l.code_addr != r.code_addr) |
| 349 | /* If .code addresses are different, the frames are different. */ |
| 350 | eq = 0; |
| 351 | else if (!l.special_addr_p || !r.special_addr_p) |
| 352 | /* An invalid special addr is a wild card (or unused), always succeed. */ |
| 353 | eq = 1; |
| 354 | else if (l.special_addr == r.special_addr) |
| 355 | /* Frames are equal. */ |
| 356 | eq = 1; |
| 357 | else |
| 358 | /* No luck. */ |
| 359 | eq = 0; |
| 360 | if (frame_debug) |
| 361 | { |
| 362 | fprintf_unfiltered (gdb_stdlog, "{ frame_id_eq (l="); |
| 363 | fprint_frame_id (gdb_stdlog, l); |
| 364 | fprintf_unfiltered (gdb_stdlog, ",r="); |
| 365 | fprint_frame_id (gdb_stdlog, r); |
| 366 | fprintf_unfiltered (gdb_stdlog, ") -> %d }\n", eq); |
| 367 | } |
| 368 | return eq; |
| 369 | } |
| 370 | |
| 371 | /* Safety net to check whether frame ID L should be inner to |
| 372 | frame ID R, according to their stack addresses. |
| 373 | |
| 374 | This method cannot be used to compare arbitrary frames, as the |
| 375 | ranges of valid stack addresses may be discontiguous (e.g. due |
| 376 | to sigaltstack). |
| 377 | |
| 378 | However, it can be used as safety net to discover invalid frame |
| 379 | IDs in certain circumstances. |
| 380 | |
| 381 | * If frame NEXT is the immediate inner frame to THIS, and NEXT |
| 382 | is a NORMAL frame, then the stack address of NEXT must be |
| 383 | inner-than-or-equal to the stack address of THIS. |
| 384 | |
| 385 | Therefore, if frame_id_inner (THIS, NEXT) holds, some unwind |
| 386 | error has occurred. |
| 387 | |
| 388 | * If frame NEXT is the immediate inner frame to THIS, and NEXT |
| 389 | is a NORMAL frame, and NEXT and THIS have different stack |
| 390 | addresses, no other frame in the frame chain may have a stack |
| 391 | address in between. |
| 392 | |
| 393 | Therefore, if frame_id_inner (TEST, THIS) holds, but |
| 394 | frame_id_inner (TEST, NEXT) does not hold, TEST cannot refer |
| 395 | to a valid frame in the frame chain. */ |
| 396 | |
| 397 | static int |
| 398 | frame_id_inner (struct gdbarch *gdbarch, struct frame_id l, struct frame_id r) |
| 399 | { |
| 400 | int inner; |
| 401 | if (!l.stack_addr_p || !r.stack_addr_p) |
| 402 | /* Like NaN, any operation involving an invalid ID always fails. */ |
| 403 | inner = 0; |
| 404 | else |
| 405 | /* Only return non-zero when strictly inner than. Note that, per |
| 406 | comment in "frame.h", there is some fuzz here. Frameless |
| 407 | functions are not strictly inner than (same .stack but |
| 408 | different .code and/or .special address). */ |
| 409 | inner = gdbarch_inner_than (gdbarch, l.stack_addr, r.stack_addr); |
| 410 | if (frame_debug) |
| 411 | { |
| 412 | fprintf_unfiltered (gdb_stdlog, "{ frame_id_inner (l="); |
| 413 | fprint_frame_id (gdb_stdlog, l); |
| 414 | fprintf_unfiltered (gdb_stdlog, ",r="); |
| 415 | fprint_frame_id (gdb_stdlog, r); |
| 416 | fprintf_unfiltered (gdb_stdlog, ") -> %d }\n", inner); |
| 417 | } |
| 418 | return inner; |
| 419 | } |
| 420 | |
| 421 | struct frame_info * |
| 422 | frame_find_by_id (struct frame_id id) |
| 423 | { |
| 424 | struct frame_info *frame, *prev_frame; |
| 425 | |
| 426 | /* ZERO denotes the null frame, let the caller decide what to do |
| 427 | about it. Should it instead return get_current_frame()? */ |
| 428 | if (!frame_id_p (id)) |
| 429 | return NULL; |
| 430 | |
| 431 | for (frame = get_current_frame (); ; frame = prev_frame) |
| 432 | { |
| 433 | struct frame_id this = get_frame_id (frame); |
| 434 | if (frame_id_eq (id, this)) |
| 435 | /* An exact match. */ |
| 436 | return frame; |
| 437 | |
| 438 | prev_frame = get_prev_frame (frame); |
| 439 | if (!prev_frame) |
| 440 | return NULL; |
| 441 | |
| 442 | /* As a safety net to avoid unnecessary backtracing while trying |
| 443 | to find an invalid ID, we check for a common situation where |
| 444 | we can detect from comparing stack addresses that no other |
| 445 | frame in the current frame chain can have this ID. See the |
| 446 | comment at frame_id_inner for details. */ |
| 447 | if (get_frame_type (frame) == NORMAL_FRAME |
| 448 | && !frame_id_inner (get_frame_arch (frame), id, this) |
| 449 | && frame_id_inner (get_frame_arch (prev_frame), id, |
| 450 | get_frame_id (prev_frame))) |
| 451 | return NULL; |
| 452 | } |
| 453 | return NULL; |
| 454 | } |
| 455 | |
| 456 | CORE_ADDR |
| 457 | frame_pc_unwind (struct frame_info *this_frame) |
| 458 | { |
| 459 | if (!this_frame->prev_pc.p) |
| 460 | { |
| 461 | CORE_ADDR pc; |
| 462 | if (gdbarch_unwind_pc_p (get_frame_arch (this_frame))) |
| 463 | { |
| 464 | /* The right way. The `pure' way. The one true way. This |
| 465 | method depends solely on the register-unwind code to |
| 466 | determine the value of registers in THIS frame, and hence |
| 467 | the value of this frame's PC (resume address). A typical |
| 468 | implementation is no more than: |
| 469 | |
| 470 | frame_unwind_register (this_frame, ISA_PC_REGNUM, buf); |
| 471 | return extract_unsigned_integer (buf, size of ISA_PC_REGNUM); |
| 472 | |
| 473 | Note: this method is very heavily dependent on a correct |
| 474 | register-unwind implementation, it pays to fix that |
| 475 | method first; this method is frame type agnostic, since |
| 476 | it only deals with register values, it works with any |
| 477 | frame. This is all in stark contrast to the old |
| 478 | FRAME_SAVED_PC which would try to directly handle all the |
| 479 | different ways that a PC could be unwound. */ |
| 480 | pc = gdbarch_unwind_pc (get_frame_arch (this_frame), this_frame); |
| 481 | } |
| 482 | else |
| 483 | internal_error (__FILE__, __LINE__, _("No unwind_pc method")); |
| 484 | this_frame->prev_pc.value = pc; |
| 485 | this_frame->prev_pc.p = 1; |
| 486 | if (frame_debug) |
| 487 | fprintf_unfiltered (gdb_stdlog, |
| 488 | "{ frame_pc_unwind (this_frame=%d) -> 0x%s }\n", |
| 489 | this_frame->level, |
| 490 | paddr_nz (this_frame->prev_pc.value)); |
| 491 | } |
| 492 | return this_frame->prev_pc.value; |
| 493 | } |
| 494 | |
| 495 | CORE_ADDR |
| 496 | get_frame_func (struct frame_info *this_frame) |
| 497 | { |
| 498 | struct frame_info *next_frame = this_frame->next; |
| 499 | |
| 500 | if (!next_frame->prev_func.p) |
| 501 | { |
| 502 | /* Make certain that this, and not the adjacent, function is |
| 503 | found. */ |
| 504 | CORE_ADDR addr_in_block = get_frame_address_in_block (this_frame); |
| 505 | next_frame->prev_func.p = 1; |
| 506 | next_frame->prev_func.addr = get_pc_function_start (addr_in_block); |
| 507 | if (frame_debug) |
| 508 | fprintf_unfiltered (gdb_stdlog, |
| 509 | "{ get_frame_func (this_frame=%d) -> 0x%s }\n", |
| 510 | this_frame->level, |
| 511 | paddr_nz (next_frame->prev_func.addr)); |
| 512 | } |
| 513 | return next_frame->prev_func.addr; |
| 514 | } |
| 515 | |
| 516 | static int |
| 517 | do_frame_register_read (void *src, int regnum, gdb_byte *buf) |
| 518 | { |
| 519 | return frame_register_read (src, regnum, buf); |
| 520 | } |
| 521 | |
| 522 | struct regcache * |
| 523 | frame_save_as_regcache (struct frame_info *this_frame) |
| 524 | { |
| 525 | struct regcache *regcache = regcache_xmalloc (get_frame_arch (this_frame)); |
| 526 | struct cleanup *cleanups = make_cleanup_regcache_xfree (regcache); |
| 527 | regcache_save (regcache, do_frame_register_read, this_frame); |
| 528 | discard_cleanups (cleanups); |
| 529 | return regcache; |
| 530 | } |
| 531 | |
| 532 | void |
| 533 | frame_pop (struct frame_info *this_frame) |
| 534 | { |
| 535 | struct frame_info *prev_frame; |
| 536 | struct regcache *scratch; |
| 537 | struct cleanup *cleanups; |
| 538 | |
| 539 | /* Ensure that we have a frame to pop to. */ |
| 540 | prev_frame = get_prev_frame_1 (this_frame); |
| 541 | |
| 542 | if (!prev_frame) |
| 543 | error (_("Cannot pop the initial frame.")); |
| 544 | |
| 545 | /* Make a copy of all the register values unwound from this frame. |
| 546 | Save them in a scratch buffer so that there isn't a race between |
| 547 | trying to extract the old values from the current regcache while |
| 548 | at the same time writing new values into that same cache. */ |
| 549 | scratch = frame_save_as_regcache (prev_frame); |
| 550 | cleanups = make_cleanup_regcache_xfree (scratch); |
| 551 | |
| 552 | /* If we are popping a dummy frame, clean up the associated |
| 553 | data as well. */ |
| 554 | if (get_frame_type (this_frame) == DUMMY_FRAME) |
| 555 | dummy_frame_pop (get_frame_id (this_frame)); |
| 556 | |
| 557 | /* FIXME: cagney/2003-03-16: It should be possible to tell the |
| 558 | target's register cache that it is about to be hit with a burst |
| 559 | register transfer and that the sequence of register writes should |
| 560 | be batched. The pair target_prepare_to_store() and |
| 561 | target_store_registers() kind of suggest this functionality. |
| 562 | Unfortunately, they don't implement it. Their lack of a formal |
| 563 | definition can lead to targets writing back bogus values |
| 564 | (arguably a bug in the target code mind). */ |
| 565 | /* Now copy those saved registers into the current regcache. |
| 566 | Here, regcache_cpy() calls regcache_restore(). */ |
| 567 | regcache_cpy (get_current_regcache (), scratch); |
| 568 | do_cleanups (cleanups); |
| 569 | |
| 570 | /* We've made right mess of GDB's local state, just discard |
| 571 | everything. */ |
| 572 | reinit_frame_cache (); |
| 573 | } |
| 574 | |
| 575 | void |
| 576 | frame_register_unwind (struct frame_info *frame, int regnum, |
| 577 | int *optimizedp, enum lval_type *lvalp, |
| 578 | CORE_ADDR *addrp, int *realnump, gdb_byte *bufferp) |
| 579 | { |
| 580 | struct value *value; |
| 581 | |
| 582 | /* Require all but BUFFERP to be valid. A NULL BUFFERP indicates |
| 583 | that the value proper does not need to be fetched. */ |
| 584 | gdb_assert (optimizedp != NULL); |
| 585 | gdb_assert (lvalp != NULL); |
| 586 | gdb_assert (addrp != NULL); |
| 587 | gdb_assert (realnump != NULL); |
| 588 | /* gdb_assert (bufferp != NULL); */ |
| 589 | |
| 590 | value = frame_unwind_register_value (frame, regnum); |
| 591 | |
| 592 | gdb_assert (value != NULL); |
| 593 | |
| 594 | *optimizedp = value_optimized_out (value); |
| 595 | *lvalp = VALUE_LVAL (value); |
| 596 | *addrp = VALUE_ADDRESS (value); |
| 597 | *realnump = VALUE_REGNUM (value); |
| 598 | |
| 599 | if (bufferp) |
| 600 | memcpy (bufferp, value_contents_all (value), |
| 601 | TYPE_LENGTH (value_type (value))); |
| 602 | |
| 603 | /* Dispose of the new value. This prevents watchpoints from |
| 604 | trying to watch the saved frame pointer. */ |
| 605 | release_value (value); |
| 606 | value_free (value); |
| 607 | } |
| 608 | |
| 609 | void |
| 610 | frame_register (struct frame_info *frame, int regnum, |
| 611 | int *optimizedp, enum lval_type *lvalp, |
| 612 | CORE_ADDR *addrp, int *realnump, gdb_byte *bufferp) |
| 613 | { |
| 614 | /* Require all but BUFFERP to be valid. A NULL BUFFERP indicates |
| 615 | that the value proper does not need to be fetched. */ |
| 616 | gdb_assert (optimizedp != NULL); |
| 617 | gdb_assert (lvalp != NULL); |
| 618 | gdb_assert (addrp != NULL); |
| 619 | gdb_assert (realnump != NULL); |
| 620 | /* gdb_assert (bufferp != NULL); */ |
| 621 | |
| 622 | /* Obtain the register value by unwinding the register from the next |
| 623 | (more inner frame). */ |
| 624 | gdb_assert (frame != NULL && frame->next != NULL); |
| 625 | frame_register_unwind (frame->next, regnum, optimizedp, lvalp, addrp, |
| 626 | realnump, bufferp); |
| 627 | } |
| 628 | |
| 629 | void |
| 630 | frame_unwind_register (struct frame_info *frame, int regnum, gdb_byte *buf) |
| 631 | { |
| 632 | int optimized; |
| 633 | CORE_ADDR addr; |
| 634 | int realnum; |
| 635 | enum lval_type lval; |
| 636 | frame_register_unwind (frame, regnum, &optimized, &lval, &addr, |
| 637 | &realnum, buf); |
| 638 | } |
| 639 | |
| 640 | void |
| 641 | get_frame_register (struct frame_info *frame, |
| 642 | int regnum, gdb_byte *buf) |
| 643 | { |
| 644 | frame_unwind_register (frame->next, regnum, buf); |
| 645 | } |
| 646 | |
| 647 | struct value * |
| 648 | frame_unwind_register_value (struct frame_info *frame, int regnum) |
| 649 | { |
| 650 | struct value *value; |
| 651 | |
| 652 | gdb_assert (frame != NULL); |
| 653 | |
| 654 | if (frame_debug) |
| 655 | { |
| 656 | fprintf_unfiltered (gdb_stdlog, "\ |
| 657 | { frame_unwind_register_value (frame=%d,regnum=%d(%s),...) ", |
| 658 | frame->level, regnum, |
| 659 | user_reg_map_regnum_to_name |
| 660 | (get_frame_arch (frame), regnum)); |
| 661 | } |
| 662 | |
| 663 | /* Find the unwinder. */ |
| 664 | if (frame->unwind == NULL) |
| 665 | frame->unwind = frame_unwind_find_by_frame (frame, &frame->prologue_cache); |
| 666 | |
| 667 | /* Ask this frame to unwind its register. */ |
| 668 | value = frame->unwind->prev_register (frame, &frame->prologue_cache, regnum); |
| 669 | |
| 670 | if (frame_debug) |
| 671 | { |
| 672 | fprintf_unfiltered (gdb_stdlog, "->"); |
| 673 | if (value_optimized_out (value)) |
| 674 | fprintf_unfiltered (gdb_stdlog, " optimized out"); |
| 675 | else |
| 676 | { |
| 677 | if (VALUE_LVAL (value) == lval_register) |
| 678 | fprintf_unfiltered (gdb_stdlog, " register=%d", |
| 679 | VALUE_REGNUM (value)); |
| 680 | else if (VALUE_LVAL (value) == lval_memory) |
| 681 | fprintf_unfiltered (gdb_stdlog, " address=0x%s", |
| 682 | paddr_nz (VALUE_ADDRESS (value))); |
| 683 | else |
| 684 | fprintf_unfiltered (gdb_stdlog, " computed"); |
| 685 | |
| 686 | if (value_lazy (value)) |
| 687 | fprintf_unfiltered (gdb_stdlog, " lazy"); |
| 688 | else |
| 689 | { |
| 690 | int i; |
| 691 | const gdb_byte *buf = value_contents (value); |
| 692 | |
| 693 | fprintf_unfiltered (gdb_stdlog, " bytes="); |
| 694 | fprintf_unfiltered (gdb_stdlog, "["); |
| 695 | for (i = 0; i < register_size (get_frame_arch (frame), regnum); i++) |
| 696 | fprintf_unfiltered (gdb_stdlog, "%02x", buf[i]); |
| 697 | fprintf_unfiltered (gdb_stdlog, "]"); |
| 698 | } |
| 699 | } |
| 700 | |
| 701 | fprintf_unfiltered (gdb_stdlog, " }\n"); |
| 702 | } |
| 703 | |
| 704 | return value; |
| 705 | } |
| 706 | |
| 707 | struct value * |
| 708 | get_frame_register_value (struct frame_info *frame, int regnum) |
| 709 | { |
| 710 | return frame_unwind_register_value (frame->next, regnum); |
| 711 | } |
| 712 | |
| 713 | LONGEST |
| 714 | frame_unwind_register_signed (struct frame_info *frame, int regnum) |
| 715 | { |
| 716 | gdb_byte buf[MAX_REGISTER_SIZE]; |
| 717 | frame_unwind_register (frame, regnum, buf); |
| 718 | return extract_signed_integer (buf, register_size (get_frame_arch (frame), |
| 719 | regnum)); |
| 720 | } |
| 721 | |
| 722 | LONGEST |
| 723 | get_frame_register_signed (struct frame_info *frame, int regnum) |
| 724 | { |
| 725 | return frame_unwind_register_signed (frame->next, regnum); |
| 726 | } |
| 727 | |
| 728 | ULONGEST |
| 729 | frame_unwind_register_unsigned (struct frame_info *frame, int regnum) |
| 730 | { |
| 731 | gdb_byte buf[MAX_REGISTER_SIZE]; |
| 732 | frame_unwind_register (frame, regnum, buf); |
| 733 | return extract_unsigned_integer (buf, register_size (get_frame_arch (frame), |
| 734 | regnum)); |
| 735 | } |
| 736 | |
| 737 | ULONGEST |
| 738 | get_frame_register_unsigned (struct frame_info *frame, int regnum) |
| 739 | { |
| 740 | return frame_unwind_register_unsigned (frame->next, regnum); |
| 741 | } |
| 742 | |
| 743 | void |
| 744 | put_frame_register (struct frame_info *frame, int regnum, |
| 745 | const gdb_byte *buf) |
| 746 | { |
| 747 | struct gdbarch *gdbarch = get_frame_arch (frame); |
| 748 | int realnum; |
| 749 | int optim; |
| 750 | enum lval_type lval; |
| 751 | CORE_ADDR addr; |
| 752 | frame_register (frame, regnum, &optim, &lval, &addr, &realnum, NULL); |
| 753 | if (optim) |
| 754 | error (_("Attempt to assign to a value that was optimized out.")); |
| 755 | switch (lval) |
| 756 | { |
| 757 | case lval_memory: |
| 758 | { |
| 759 | /* FIXME: write_memory doesn't yet take constant buffers. |
| 760 | Arrrg! */ |
| 761 | gdb_byte tmp[MAX_REGISTER_SIZE]; |
| 762 | memcpy (tmp, buf, register_size (gdbarch, regnum)); |
| 763 | write_memory (addr, tmp, register_size (gdbarch, regnum)); |
| 764 | break; |
| 765 | } |
| 766 | case lval_register: |
| 767 | regcache_cooked_write (get_current_regcache (), realnum, buf); |
| 768 | break; |
| 769 | default: |
| 770 | error (_("Attempt to assign to an unmodifiable value.")); |
| 771 | } |
| 772 | } |
| 773 | |
| 774 | /* frame_register_read () |
| 775 | |
| 776 | Find and return the value of REGNUM for the specified stack frame. |
| 777 | The number of bytes copied is REGISTER_SIZE (REGNUM). |
| 778 | |
| 779 | Returns 0 if the register value could not be found. */ |
| 780 | |
| 781 | int |
| 782 | frame_register_read (struct frame_info *frame, int regnum, |
| 783 | gdb_byte *myaddr) |
| 784 | { |
| 785 | int optimized; |
| 786 | enum lval_type lval; |
| 787 | CORE_ADDR addr; |
| 788 | int realnum; |
| 789 | frame_register (frame, regnum, &optimized, &lval, &addr, &realnum, myaddr); |
| 790 | |
| 791 | return !optimized; |
| 792 | } |
| 793 | |
| 794 | int |
| 795 | get_frame_register_bytes (struct frame_info *frame, int regnum, |
| 796 | CORE_ADDR offset, int len, gdb_byte *myaddr) |
| 797 | { |
| 798 | struct gdbarch *gdbarch = get_frame_arch (frame); |
| 799 | int i; |
| 800 | int maxsize; |
| 801 | |
| 802 | /* Skip registers wholly inside of OFFSET. */ |
| 803 | while (offset >= register_size (gdbarch, regnum)) |
| 804 | { |
| 805 | offset -= register_size (gdbarch, regnum); |
| 806 | regnum++; |
| 807 | } |
| 808 | |
| 809 | /* Detect bad debug info. */ |
| 810 | maxsize = -offset; |
| 811 | for (i = regnum; i < gdbarch_num_regs (gdbarch); i++) |
| 812 | { |
| 813 | int thissize = register_size (gdbarch, i); |
| 814 | if (thissize == 0) |
| 815 | break; |
| 816 | maxsize += thissize; |
| 817 | } |
| 818 | if (len > maxsize) |
| 819 | { |
| 820 | warning (_("Bad debug information detected: " |
| 821 | "Attempt to read %d bytes from registers."), len); |
| 822 | return 0; |
| 823 | } |
| 824 | |
| 825 | /* Copy the data. */ |
| 826 | while (len > 0) |
| 827 | { |
| 828 | int curr_len = register_size (gdbarch, regnum) - offset; |
| 829 | if (curr_len > len) |
| 830 | curr_len = len; |
| 831 | |
| 832 | if (curr_len == register_size (gdbarch, regnum)) |
| 833 | { |
| 834 | if (!frame_register_read (frame, regnum, myaddr)) |
| 835 | return 0; |
| 836 | } |
| 837 | else |
| 838 | { |
| 839 | gdb_byte buf[MAX_REGISTER_SIZE]; |
| 840 | if (!frame_register_read (frame, regnum, buf)) |
| 841 | return 0; |
| 842 | memcpy (myaddr, buf + offset, curr_len); |
| 843 | } |
| 844 | |
| 845 | myaddr += curr_len; |
| 846 | len -= curr_len; |
| 847 | offset = 0; |
| 848 | regnum++; |
| 849 | } |
| 850 | |
| 851 | return 1; |
| 852 | } |
| 853 | |
| 854 | void |
| 855 | put_frame_register_bytes (struct frame_info *frame, int regnum, |
| 856 | CORE_ADDR offset, int len, const gdb_byte *myaddr) |
| 857 | { |
| 858 | struct gdbarch *gdbarch = get_frame_arch (frame); |
| 859 | |
| 860 | /* Skip registers wholly inside of OFFSET. */ |
| 861 | while (offset >= register_size (gdbarch, regnum)) |
| 862 | { |
| 863 | offset -= register_size (gdbarch, regnum); |
| 864 | regnum++; |
| 865 | } |
| 866 | |
| 867 | /* Copy the data. */ |
| 868 | while (len > 0) |
| 869 | { |
| 870 | int curr_len = register_size (gdbarch, regnum) - offset; |
| 871 | if (curr_len > len) |
| 872 | curr_len = len; |
| 873 | |
| 874 | if (curr_len == register_size (gdbarch, regnum)) |
| 875 | { |
| 876 | put_frame_register (frame, regnum, myaddr); |
| 877 | } |
| 878 | else |
| 879 | { |
| 880 | gdb_byte buf[MAX_REGISTER_SIZE]; |
| 881 | frame_register_read (frame, regnum, buf); |
| 882 | memcpy (buf + offset, myaddr, curr_len); |
| 883 | put_frame_register (frame, regnum, buf); |
| 884 | } |
| 885 | |
| 886 | myaddr += curr_len; |
| 887 | len -= curr_len; |
| 888 | offset = 0; |
| 889 | regnum++; |
| 890 | } |
| 891 | } |
| 892 | |
| 893 | /* Create a sentinel frame. */ |
| 894 | |
| 895 | static struct frame_info * |
| 896 | create_sentinel_frame (struct regcache *regcache) |
| 897 | { |
| 898 | struct frame_info *frame = FRAME_OBSTACK_ZALLOC (struct frame_info); |
| 899 | frame->level = -1; |
| 900 | /* Explicitly initialize the sentinel frame's cache. Provide it |
| 901 | with the underlying regcache. In the future additional |
| 902 | information, such as the frame's thread will be added. */ |
| 903 | frame->prologue_cache = sentinel_frame_cache (regcache); |
| 904 | /* For the moment there is only one sentinel frame implementation. */ |
| 905 | frame->unwind = sentinel_frame_unwind; |
| 906 | /* Link this frame back to itself. The frame is self referential |
| 907 | (the unwound PC is the same as the pc), so make it so. */ |
| 908 | frame->next = frame; |
| 909 | /* Make the sentinel frame's ID valid, but invalid. That way all |
| 910 | comparisons with it should fail. */ |
| 911 | frame->this_id.p = 1; |
| 912 | frame->this_id.value = null_frame_id; |
| 913 | if (frame_debug) |
| 914 | { |
| 915 | fprintf_unfiltered (gdb_stdlog, "{ create_sentinel_frame (...) -> "); |
| 916 | fprint_frame (gdb_stdlog, frame); |
| 917 | fprintf_unfiltered (gdb_stdlog, " }\n"); |
| 918 | } |
| 919 | return frame; |
| 920 | } |
| 921 | |
| 922 | /* Info about the innermost stack frame (contents of FP register) */ |
| 923 | |
| 924 | static struct frame_info *current_frame; |
| 925 | |
| 926 | /* Cache for frame addresses already read by gdb. Valid only while |
| 927 | inferior is stopped. Control variables for the frame cache should |
| 928 | be local to this module. */ |
| 929 | |
| 930 | static struct obstack frame_cache_obstack; |
| 931 | |
| 932 | void * |
| 933 | frame_obstack_zalloc (unsigned long size) |
| 934 | { |
| 935 | void *data = obstack_alloc (&frame_cache_obstack, size); |
| 936 | memset (data, 0, size); |
| 937 | return data; |
| 938 | } |
| 939 | |
| 940 | /* Return the innermost (currently executing) stack frame. This is |
| 941 | split into two functions. The function unwind_to_current_frame() |
| 942 | is wrapped in catch exceptions so that, even when the unwind of the |
| 943 | sentinel frame fails, the function still returns a stack frame. */ |
| 944 | |
| 945 | static int |
| 946 | unwind_to_current_frame (struct ui_out *ui_out, void *args) |
| 947 | { |
| 948 | struct frame_info *frame = get_prev_frame (args); |
| 949 | /* A sentinel frame can fail to unwind, e.g., because its PC value |
| 950 | lands in somewhere like start. */ |
| 951 | if (frame == NULL) |
| 952 | return 1; |
| 953 | current_frame = frame; |
| 954 | return 0; |
| 955 | } |
| 956 | |
| 957 | struct frame_info * |
| 958 | get_current_frame (void) |
| 959 | { |
| 960 | /* First check, and report, the lack of registers. Having GDB |
| 961 | report "No stack!" or "No memory" when the target doesn't even |
| 962 | have registers is very confusing. Besides, "printcmd.exp" |
| 963 | explicitly checks that ``print $pc'' with no registers prints "No |
| 964 | registers". */ |
| 965 | if (!target_has_registers) |
| 966 | error (_("No registers.")); |
| 967 | if (!target_has_stack) |
| 968 | error (_("No stack.")); |
| 969 | if (!target_has_memory) |
| 970 | error (_("No memory.")); |
| 971 | if (is_executing (inferior_ptid)) |
| 972 | error (_("Target is executing.")); |
| 973 | |
| 974 | if (current_frame == NULL) |
| 975 | { |
| 976 | struct frame_info *sentinel_frame = |
| 977 | create_sentinel_frame (get_current_regcache ()); |
| 978 | if (catch_exceptions (uiout, unwind_to_current_frame, sentinel_frame, |
| 979 | RETURN_MASK_ERROR) != 0) |
| 980 | { |
| 981 | /* Oops! Fake a current frame? Is this useful? It has a PC |
| 982 | of zero, for instance. */ |
| 983 | current_frame = sentinel_frame; |
| 984 | } |
| 985 | } |
| 986 | return current_frame; |
| 987 | } |
| 988 | |
| 989 | /* The "selected" stack frame is used by default for local and arg |
| 990 | access. May be zero, for no selected frame. */ |
| 991 | |
| 992 | static struct frame_info *selected_frame; |
| 993 | |
| 994 | static int |
| 995 | has_stack_frames (void) |
| 996 | { |
| 997 | if (!target_has_registers || !target_has_stack || !target_has_memory) |
| 998 | return 0; |
| 999 | |
| 1000 | /* If the current thread is executing, don't try to read from |
| 1001 | it. */ |
| 1002 | if (is_executing (inferior_ptid)) |
| 1003 | return 0; |
| 1004 | |
| 1005 | return 1; |
| 1006 | } |
| 1007 | |
| 1008 | /* Return the selected frame. Always non-NULL (unless there isn't an |
| 1009 | inferior sufficient for creating a frame) in which case an error is |
| 1010 | thrown. */ |
| 1011 | |
| 1012 | struct frame_info * |
| 1013 | get_selected_frame (const char *message) |
| 1014 | { |
| 1015 | if (selected_frame == NULL) |
| 1016 | { |
| 1017 | if (message != NULL && !has_stack_frames ()) |
| 1018 | error (("%s"), message); |
| 1019 | /* Hey! Don't trust this. It should really be re-finding the |
| 1020 | last selected frame of the currently selected thread. This, |
| 1021 | though, is better than nothing. */ |
| 1022 | select_frame (get_current_frame ()); |
| 1023 | } |
| 1024 | /* There is always a frame. */ |
| 1025 | gdb_assert (selected_frame != NULL); |
| 1026 | return selected_frame; |
| 1027 | } |
| 1028 | |
| 1029 | /* This is a variant of get_selected_frame() which can be called when |
| 1030 | the inferior does not have a frame; in that case it will return |
| 1031 | NULL instead of calling error(). */ |
| 1032 | |
| 1033 | struct frame_info * |
| 1034 | deprecated_safe_get_selected_frame (void) |
| 1035 | { |
| 1036 | if (!has_stack_frames ()) |
| 1037 | return NULL; |
| 1038 | return get_selected_frame (NULL); |
| 1039 | } |
| 1040 | |
| 1041 | /* Select frame FI (or NULL - to invalidate the current frame). */ |
| 1042 | |
| 1043 | void |
| 1044 | select_frame (struct frame_info *fi) |
| 1045 | { |
| 1046 | struct symtab *s; |
| 1047 | |
| 1048 | selected_frame = fi; |
| 1049 | /* NOTE: cagney/2002-05-04: FI can be NULL. This occurs when the |
| 1050 | frame is being invalidated. */ |
| 1051 | if (deprecated_selected_frame_level_changed_hook) |
| 1052 | deprecated_selected_frame_level_changed_hook (frame_relative_level (fi)); |
| 1053 | |
| 1054 | /* FIXME: kseitz/2002-08-28: It would be nice to call |
| 1055 | selected_frame_level_changed_event() right here, but due to limitations |
| 1056 | in the current interfaces, we would end up flooding UIs with events |
| 1057 | because select_frame() is used extensively internally. |
| 1058 | |
| 1059 | Once we have frame-parameterized frame (and frame-related) commands, |
| 1060 | the event notification can be moved here, since this function will only |
| 1061 | be called when the user's selected frame is being changed. */ |
| 1062 | |
| 1063 | /* Ensure that symbols for this frame are read in. Also, determine the |
| 1064 | source language of this frame, and switch to it if desired. */ |
| 1065 | if (fi) |
| 1066 | { |
| 1067 | /* We retrieve the frame's symtab by using the frame PC. However |
| 1068 | we cannot use the frame PC as-is, because it usually points to |
| 1069 | the instruction following the "call", which is sometimes the |
| 1070 | first instruction of another function. So we rely on |
| 1071 | get_frame_address_in_block() which provides us with a PC which |
| 1072 | is guaranteed to be inside the frame's code block. */ |
| 1073 | s = find_pc_symtab (get_frame_address_in_block (fi)); |
| 1074 | if (s |
| 1075 | && s->language != current_language->la_language |
| 1076 | && s->language != language_unknown |
| 1077 | && language_mode == language_mode_auto) |
| 1078 | { |
| 1079 | set_language (s->language); |
| 1080 | } |
| 1081 | } |
| 1082 | } |
| 1083 | |
| 1084 | /* Create an arbitrary (i.e. address specified by user) or innermost frame. |
| 1085 | Always returns a non-NULL value. */ |
| 1086 | |
| 1087 | struct frame_info * |
| 1088 | create_new_frame (CORE_ADDR addr, CORE_ADDR pc) |
| 1089 | { |
| 1090 | struct frame_info *fi; |
| 1091 | |
| 1092 | if (frame_debug) |
| 1093 | { |
| 1094 | fprintf_unfiltered (gdb_stdlog, |
| 1095 | "{ create_new_frame (addr=0x%s, pc=0x%s) ", |
| 1096 | paddr_nz (addr), paddr_nz (pc)); |
| 1097 | } |
| 1098 | |
| 1099 | fi = FRAME_OBSTACK_ZALLOC (struct frame_info); |
| 1100 | |
| 1101 | fi->next = create_sentinel_frame (get_current_regcache ()); |
| 1102 | |
| 1103 | /* Select/initialize both the unwind function and the frame's type |
| 1104 | based on the PC. */ |
| 1105 | fi->unwind = frame_unwind_find_by_frame (fi, &fi->prologue_cache); |
| 1106 | |
| 1107 | fi->this_id.p = 1; |
| 1108 | deprecated_update_frame_base_hack (fi, addr); |
| 1109 | deprecated_update_frame_pc_hack (fi, pc); |
| 1110 | |
| 1111 | if (frame_debug) |
| 1112 | { |
| 1113 | fprintf_unfiltered (gdb_stdlog, "-> "); |
| 1114 | fprint_frame (gdb_stdlog, fi); |
| 1115 | fprintf_unfiltered (gdb_stdlog, " }\n"); |
| 1116 | } |
| 1117 | |
| 1118 | return fi; |
| 1119 | } |
| 1120 | |
| 1121 | /* Return the frame that THIS_FRAME calls (NULL if THIS_FRAME is the |
| 1122 | innermost frame). Be careful to not fall off the bottom of the |
| 1123 | frame chain and onto the sentinel frame. */ |
| 1124 | |
| 1125 | struct frame_info * |
| 1126 | get_next_frame (struct frame_info *this_frame) |
| 1127 | { |
| 1128 | if (this_frame->level > 0) |
| 1129 | return this_frame->next; |
| 1130 | else |
| 1131 | return NULL; |
| 1132 | } |
| 1133 | |
| 1134 | /* Observer for the target_changed event. */ |
| 1135 | |
| 1136 | void |
| 1137 | frame_observer_target_changed (struct target_ops *target) |
| 1138 | { |
| 1139 | reinit_frame_cache (); |
| 1140 | } |
| 1141 | |
| 1142 | /* Flush the entire frame cache. */ |
| 1143 | |
| 1144 | void |
| 1145 | reinit_frame_cache (void) |
| 1146 | { |
| 1147 | struct frame_info *fi; |
| 1148 | |
| 1149 | /* Tear down all frame caches. */ |
| 1150 | for (fi = current_frame; fi != NULL; fi = fi->prev) |
| 1151 | { |
| 1152 | if (fi->prologue_cache && fi->unwind->dealloc_cache) |
| 1153 | fi->unwind->dealloc_cache (fi, fi->prologue_cache); |
| 1154 | if (fi->base_cache && fi->base->unwind->dealloc_cache) |
| 1155 | fi->base->unwind->dealloc_cache (fi, fi->base_cache); |
| 1156 | } |
| 1157 | |
| 1158 | /* Since we can't really be sure what the first object allocated was */ |
| 1159 | obstack_free (&frame_cache_obstack, 0); |
| 1160 | obstack_init (&frame_cache_obstack); |
| 1161 | |
| 1162 | if (current_frame != NULL) |
| 1163 | annotate_frames_invalid (); |
| 1164 | |
| 1165 | current_frame = NULL; /* Invalidate cache */ |
| 1166 | select_frame (NULL); |
| 1167 | if (frame_debug) |
| 1168 | fprintf_unfiltered (gdb_stdlog, "{ reinit_frame_cache () }\n"); |
| 1169 | } |
| 1170 | |
| 1171 | /* Find where a register is saved (in memory or another register). |
| 1172 | The result of frame_register_unwind is just where it is saved |
| 1173 | relative to this particular frame. */ |
| 1174 | |
| 1175 | static void |
| 1176 | frame_register_unwind_location (struct frame_info *this_frame, int regnum, |
| 1177 | int *optimizedp, enum lval_type *lvalp, |
| 1178 | CORE_ADDR *addrp, int *realnump) |
| 1179 | { |
| 1180 | gdb_assert (this_frame == NULL || this_frame->level >= 0); |
| 1181 | |
| 1182 | while (this_frame != NULL) |
| 1183 | { |
| 1184 | frame_register_unwind (this_frame, regnum, optimizedp, lvalp, |
| 1185 | addrp, realnump, NULL); |
| 1186 | |
| 1187 | if (*optimizedp) |
| 1188 | break; |
| 1189 | |
| 1190 | if (*lvalp != lval_register) |
| 1191 | break; |
| 1192 | |
| 1193 | regnum = *realnump; |
| 1194 | this_frame = get_next_frame (this_frame); |
| 1195 | } |
| 1196 | } |
| 1197 | |
| 1198 | /* Return a "struct frame_info" corresponding to the frame that called |
| 1199 | THIS_FRAME. Returns NULL if there is no such frame. |
| 1200 | |
| 1201 | Unlike get_prev_frame, this function always tries to unwind the |
| 1202 | frame. */ |
| 1203 | |
| 1204 | static struct frame_info * |
| 1205 | get_prev_frame_1 (struct frame_info *this_frame) |
| 1206 | { |
| 1207 | struct frame_info *prev_frame; |
| 1208 | struct frame_id this_id; |
| 1209 | struct gdbarch *gdbarch; |
| 1210 | |
| 1211 | gdb_assert (this_frame != NULL); |
| 1212 | gdbarch = get_frame_arch (this_frame); |
| 1213 | |
| 1214 | if (frame_debug) |
| 1215 | { |
| 1216 | fprintf_unfiltered (gdb_stdlog, "{ get_prev_frame_1 (this_frame="); |
| 1217 | if (this_frame != NULL) |
| 1218 | fprintf_unfiltered (gdb_stdlog, "%d", this_frame->level); |
| 1219 | else |
| 1220 | fprintf_unfiltered (gdb_stdlog, "<NULL>"); |
| 1221 | fprintf_unfiltered (gdb_stdlog, ") "); |
| 1222 | } |
| 1223 | |
| 1224 | /* Only try to do the unwind once. */ |
| 1225 | if (this_frame->prev_p) |
| 1226 | { |
| 1227 | if (frame_debug) |
| 1228 | { |
| 1229 | fprintf_unfiltered (gdb_stdlog, "-> "); |
| 1230 | fprint_frame (gdb_stdlog, this_frame->prev); |
| 1231 | fprintf_unfiltered (gdb_stdlog, " // cached \n"); |
| 1232 | } |
| 1233 | return this_frame->prev; |
| 1234 | } |
| 1235 | |
| 1236 | /* If the frame unwinder hasn't been selected yet, we must do so |
| 1237 | before setting prev_p; otherwise the check for misbehaved |
| 1238 | sniffers will think that this frame's sniffer tried to unwind |
| 1239 | further (see frame_cleanup_after_sniffer). */ |
| 1240 | if (this_frame->unwind == NULL) |
| 1241 | this_frame->unwind |
| 1242 | = frame_unwind_find_by_frame (this_frame, &this_frame->prologue_cache); |
| 1243 | |
| 1244 | this_frame->prev_p = 1; |
| 1245 | this_frame->stop_reason = UNWIND_NO_REASON; |
| 1246 | |
| 1247 | /* Check that this frame's ID was valid. If it wasn't, don't try to |
| 1248 | unwind to the prev frame. Be careful to not apply this test to |
| 1249 | the sentinel frame. */ |
| 1250 | this_id = get_frame_id (this_frame); |
| 1251 | if (this_frame->level >= 0 && !frame_id_p (this_id)) |
| 1252 | { |
| 1253 | if (frame_debug) |
| 1254 | { |
| 1255 | fprintf_unfiltered (gdb_stdlog, "-> "); |
| 1256 | fprint_frame (gdb_stdlog, NULL); |
| 1257 | fprintf_unfiltered (gdb_stdlog, " // this ID is NULL }\n"); |
| 1258 | } |
| 1259 | this_frame->stop_reason = UNWIND_NULL_ID; |
| 1260 | return NULL; |
| 1261 | } |
| 1262 | |
| 1263 | /* Check that this frame's ID isn't inner to (younger, below, next) |
| 1264 | the next frame. This happens when a frame unwind goes backwards. |
| 1265 | This check is valid only if the next frame is NORMAL. See the |
| 1266 | comment at frame_id_inner for details. */ |
| 1267 | if (this_frame->next->unwind->type == NORMAL_FRAME |
| 1268 | && frame_id_inner (get_frame_arch (this_frame->next), this_id, |
| 1269 | get_frame_id (this_frame->next))) |
| 1270 | { |
| 1271 | if (frame_debug) |
| 1272 | { |
| 1273 | fprintf_unfiltered (gdb_stdlog, "-> "); |
| 1274 | fprint_frame (gdb_stdlog, NULL); |
| 1275 | fprintf_unfiltered (gdb_stdlog, " // this frame ID is inner }\n"); |
| 1276 | } |
| 1277 | this_frame->stop_reason = UNWIND_INNER_ID; |
| 1278 | return NULL; |
| 1279 | } |
| 1280 | |
| 1281 | /* Check that this and the next frame are not identical. If they |
| 1282 | are, there is most likely a stack cycle. As with the inner-than |
| 1283 | test above, avoid comparing the inner-most and sentinel frames. */ |
| 1284 | if (this_frame->level > 0 |
| 1285 | && frame_id_eq (this_id, get_frame_id (this_frame->next))) |
| 1286 | { |
| 1287 | if (frame_debug) |
| 1288 | { |
| 1289 | fprintf_unfiltered (gdb_stdlog, "-> "); |
| 1290 | fprint_frame (gdb_stdlog, NULL); |
| 1291 | fprintf_unfiltered (gdb_stdlog, " // this frame has same ID }\n"); |
| 1292 | } |
| 1293 | this_frame->stop_reason = UNWIND_SAME_ID; |
| 1294 | return NULL; |
| 1295 | } |
| 1296 | |
| 1297 | /* Check that this and the next frame do not unwind the PC register |
| 1298 | to the same memory location. If they do, then even though they |
| 1299 | have different frame IDs, the new frame will be bogus; two |
| 1300 | functions can't share a register save slot for the PC. This can |
| 1301 | happen when the prologue analyzer finds a stack adjustment, but |
| 1302 | no PC save. |
| 1303 | |
| 1304 | This check does assume that the "PC register" is roughly a |
| 1305 | traditional PC, even if the gdbarch_unwind_pc method adjusts |
| 1306 | it (we do not rely on the value, only on the unwound PC being |
| 1307 | dependent on this value). A potential improvement would be |
| 1308 | to have the frame prev_pc method and the gdbarch unwind_pc |
| 1309 | method set the same lval and location information as |
| 1310 | frame_register_unwind. */ |
| 1311 | if (this_frame->level > 0 |
| 1312 | && gdbarch_pc_regnum (gdbarch) >= 0 |
| 1313 | && get_frame_type (this_frame) == NORMAL_FRAME |
| 1314 | && get_frame_type (this_frame->next) == NORMAL_FRAME) |
| 1315 | { |
| 1316 | int optimized, realnum, nrealnum; |
| 1317 | enum lval_type lval, nlval; |
| 1318 | CORE_ADDR addr, naddr; |
| 1319 | |
| 1320 | frame_register_unwind_location (this_frame, |
| 1321 | gdbarch_pc_regnum (gdbarch), |
| 1322 | &optimized, &lval, &addr, &realnum); |
| 1323 | frame_register_unwind_location (get_next_frame (this_frame), |
| 1324 | gdbarch_pc_regnum (gdbarch), |
| 1325 | &optimized, &nlval, &naddr, &nrealnum); |
| 1326 | |
| 1327 | if ((lval == lval_memory && lval == nlval && addr == naddr) |
| 1328 | || (lval == lval_register && lval == nlval && realnum == nrealnum)) |
| 1329 | { |
| 1330 | if (frame_debug) |
| 1331 | { |
| 1332 | fprintf_unfiltered (gdb_stdlog, "-> "); |
| 1333 | fprint_frame (gdb_stdlog, NULL); |
| 1334 | fprintf_unfiltered (gdb_stdlog, " // no saved PC }\n"); |
| 1335 | } |
| 1336 | |
| 1337 | this_frame->stop_reason = UNWIND_NO_SAVED_PC; |
| 1338 | this_frame->prev = NULL; |
| 1339 | return NULL; |
| 1340 | } |
| 1341 | } |
| 1342 | |
| 1343 | /* Allocate the new frame but do not wire it in to the frame chain. |
| 1344 | Some (bad) code in INIT_FRAME_EXTRA_INFO tries to look along |
| 1345 | frame->next to pull some fancy tricks (of course such code is, by |
| 1346 | definition, recursive). Try to prevent it. |
| 1347 | |
| 1348 | There is no reason to worry about memory leaks, should the |
| 1349 | remainder of the function fail. The allocated memory will be |
| 1350 | quickly reclaimed when the frame cache is flushed, and the `we've |
| 1351 | been here before' check above will stop repeated memory |
| 1352 | allocation calls. */ |
| 1353 | prev_frame = FRAME_OBSTACK_ZALLOC (struct frame_info); |
| 1354 | prev_frame->level = this_frame->level + 1; |
| 1355 | |
| 1356 | /* Don't yet compute ->unwind (and hence ->type). It is computed |
| 1357 | on-demand in get_frame_type, frame_register_unwind, and |
| 1358 | get_frame_id. */ |
| 1359 | |
| 1360 | /* Don't yet compute the frame's ID. It is computed on-demand by |
| 1361 | get_frame_id(). */ |
| 1362 | |
| 1363 | /* The unwound frame ID is validate at the start of this function, |
| 1364 | as part of the logic to decide if that frame should be further |
| 1365 | unwound, and not here while the prev frame is being created. |
| 1366 | Doing this makes it possible for the user to examine a frame that |
| 1367 | has an invalid frame ID. |
| 1368 | |
| 1369 | Some very old VAX code noted: [...] For the sake of argument, |
| 1370 | suppose that the stack is somewhat trashed (which is one reason |
| 1371 | that "info frame" exists). So, return 0 (indicating we don't |
| 1372 | know the address of the arglist) if we don't know what frame this |
| 1373 | frame calls. */ |
| 1374 | |
| 1375 | /* Link it in. */ |
| 1376 | this_frame->prev = prev_frame; |
| 1377 | prev_frame->next = this_frame; |
| 1378 | |
| 1379 | if (frame_debug) |
| 1380 | { |
| 1381 | fprintf_unfiltered (gdb_stdlog, "-> "); |
| 1382 | fprint_frame (gdb_stdlog, prev_frame); |
| 1383 | fprintf_unfiltered (gdb_stdlog, " }\n"); |
| 1384 | } |
| 1385 | |
| 1386 | return prev_frame; |
| 1387 | } |
| 1388 | |
| 1389 | /* Debug routine to print a NULL frame being returned. */ |
| 1390 | |
| 1391 | static void |
| 1392 | frame_debug_got_null_frame (struct ui_file *file, |
| 1393 | struct frame_info *this_frame, |
| 1394 | const char *reason) |
| 1395 | { |
| 1396 | if (frame_debug) |
| 1397 | { |
| 1398 | fprintf_unfiltered (gdb_stdlog, "{ get_prev_frame (this_frame="); |
| 1399 | if (this_frame != NULL) |
| 1400 | fprintf_unfiltered (gdb_stdlog, "%d", this_frame->level); |
| 1401 | else |
| 1402 | fprintf_unfiltered (gdb_stdlog, "<NULL>"); |
| 1403 | fprintf_unfiltered (gdb_stdlog, ") -> // %s}\n", reason); |
| 1404 | } |
| 1405 | } |
| 1406 | |
| 1407 | /* Is this (non-sentinel) frame in the "main"() function? */ |
| 1408 | |
| 1409 | static int |
| 1410 | inside_main_func (struct frame_info *this_frame) |
| 1411 | { |
| 1412 | struct minimal_symbol *msymbol; |
| 1413 | CORE_ADDR maddr; |
| 1414 | |
| 1415 | if (symfile_objfile == 0) |
| 1416 | return 0; |
| 1417 | msymbol = lookup_minimal_symbol (main_name (), NULL, symfile_objfile); |
| 1418 | if (msymbol == NULL) |
| 1419 | return 0; |
| 1420 | /* Make certain that the code, and not descriptor, address is |
| 1421 | returned. */ |
| 1422 | maddr = gdbarch_convert_from_func_ptr_addr (get_frame_arch (this_frame), |
| 1423 | SYMBOL_VALUE_ADDRESS (msymbol), |
| 1424 | ¤t_target); |
| 1425 | return maddr == get_frame_func (this_frame); |
| 1426 | } |
| 1427 | |
| 1428 | /* Test whether THIS_FRAME is inside the process entry point function. */ |
| 1429 | |
| 1430 | static int |
| 1431 | inside_entry_func (struct frame_info *this_frame) |
| 1432 | { |
| 1433 | return (get_frame_func (this_frame) == entry_point_address ()); |
| 1434 | } |
| 1435 | |
| 1436 | /* Return a structure containing various interesting information about |
| 1437 | the frame that called THIS_FRAME. Returns NULL if there is entier |
| 1438 | no such frame or the frame fails any of a set of target-independent |
| 1439 | condition that should terminate the frame chain (e.g., as unwinding |
| 1440 | past main()). |
| 1441 | |
| 1442 | This function should not contain target-dependent tests, such as |
| 1443 | checking whether the program-counter is zero. */ |
| 1444 | |
| 1445 | struct frame_info * |
| 1446 | get_prev_frame (struct frame_info *this_frame) |
| 1447 | { |
| 1448 | struct frame_info *prev_frame; |
| 1449 | |
| 1450 | /* Return the inner-most frame, when the caller passes in NULL. */ |
| 1451 | /* NOTE: cagney/2002-11-09: Not sure how this would happen. The |
| 1452 | caller should have previously obtained a valid frame using |
| 1453 | get_selected_frame() and then called this code - only possibility |
| 1454 | I can think of is code behaving badly. |
| 1455 | |
| 1456 | NOTE: cagney/2003-01-10: Talk about code behaving badly. Check |
| 1457 | block_innermost_frame(). It does the sequence: frame = NULL; |
| 1458 | while (1) { frame = get_prev_frame (frame); .... }. Ulgh! Why |
| 1459 | it couldn't be written better, I don't know. |
| 1460 | |
| 1461 | NOTE: cagney/2003-01-11: I suspect what is happening in |
| 1462 | block_innermost_frame() is, when the target has no state |
| 1463 | (registers, memory, ...), it is still calling this function. The |
| 1464 | assumption being that this function will return NULL indicating |
| 1465 | that a frame isn't possible, rather than checking that the target |
| 1466 | has state and then calling get_current_frame() and |
| 1467 | get_prev_frame(). This is a guess mind. */ |
| 1468 | if (this_frame == NULL) |
| 1469 | { |
| 1470 | /* NOTE: cagney/2002-11-09: There was a code segment here that |
| 1471 | would error out when CURRENT_FRAME was NULL. The comment |
| 1472 | that went with it made the claim ... |
| 1473 | |
| 1474 | ``This screws value_of_variable, which just wants a nice |
| 1475 | clean NULL return from block_innermost_frame if there are no |
| 1476 | frames. I don't think I've ever seen this message happen |
| 1477 | otherwise. And returning NULL here is a perfectly legitimate |
| 1478 | thing to do.'' |
| 1479 | |
| 1480 | Per the above, this code shouldn't even be called with a NULL |
| 1481 | THIS_FRAME. */ |
| 1482 | frame_debug_got_null_frame (gdb_stdlog, this_frame, "this_frame NULL"); |
| 1483 | return current_frame; |
| 1484 | } |
| 1485 | |
| 1486 | /* There is always a frame. If this assertion fails, suspect that |
| 1487 | something should be calling get_selected_frame() or |
| 1488 | get_current_frame(). */ |
| 1489 | gdb_assert (this_frame != NULL); |
| 1490 | |
| 1491 | /* tausq/2004-12-07: Dummy frames are skipped because it doesn't make much |
| 1492 | sense to stop unwinding at a dummy frame. One place where a dummy |
| 1493 | frame may have an address "inside_main_func" is on HPUX. On HPUX, the |
| 1494 | pcsqh register (space register for the instruction at the head of the |
| 1495 | instruction queue) cannot be written directly; the only way to set it |
| 1496 | is to branch to code that is in the target space. In order to implement |
| 1497 | frame dummies on HPUX, the called function is made to jump back to where |
| 1498 | the inferior was when the user function was called. If gdb was inside |
| 1499 | the main function when we created the dummy frame, the dummy frame will |
| 1500 | point inside the main function. */ |
| 1501 | if (this_frame->level >= 0 |
| 1502 | && get_frame_type (this_frame) != DUMMY_FRAME |
| 1503 | && !backtrace_past_main |
| 1504 | && inside_main_func (this_frame)) |
| 1505 | /* Don't unwind past main(). Note, this is done _before_ the |
| 1506 | frame has been marked as previously unwound. That way if the |
| 1507 | user later decides to enable unwinds past main(), that will |
| 1508 | automatically happen. */ |
| 1509 | { |
| 1510 | frame_debug_got_null_frame (gdb_stdlog, this_frame, "inside main func"); |
| 1511 | return NULL; |
| 1512 | } |
| 1513 | |
| 1514 | /* If the user's backtrace limit has been exceeded, stop. We must |
| 1515 | add two to the current level; one of those accounts for backtrace_limit |
| 1516 | being 1-based and the level being 0-based, and the other accounts for |
| 1517 | the level of the new frame instead of the level of the current |
| 1518 | frame. */ |
| 1519 | if (this_frame->level + 2 > backtrace_limit) |
| 1520 | { |
| 1521 | frame_debug_got_null_frame (gdb_stdlog, this_frame, |
| 1522 | "backtrace limit exceeded"); |
| 1523 | return NULL; |
| 1524 | } |
| 1525 | |
| 1526 | /* If we're already inside the entry function for the main objfile, |
| 1527 | then it isn't valid. Don't apply this test to a dummy frame - |
| 1528 | dummy frame PCs typically land in the entry func. Don't apply |
| 1529 | this test to the sentinel frame. Sentinel frames should always |
| 1530 | be allowed to unwind. */ |
| 1531 | /* NOTE: cagney/2003-07-07: Fixed a bug in inside_main_func() - |
| 1532 | wasn't checking for "main" in the minimal symbols. With that |
| 1533 | fixed asm-source tests now stop in "main" instead of halting the |
| 1534 | backtrace in weird and wonderful ways somewhere inside the entry |
| 1535 | file. Suspect that tests for inside the entry file/func were |
| 1536 | added to work around that (now fixed) case. */ |
| 1537 | /* NOTE: cagney/2003-07-15: danielj (if I'm reading it right) |
| 1538 | suggested having the inside_entry_func test use the |
| 1539 | inside_main_func() msymbol trick (along with entry_point_address() |
| 1540 | I guess) to determine the address range of the start function. |
| 1541 | That should provide a far better stopper than the current |
| 1542 | heuristics. */ |
| 1543 | /* NOTE: tausq/2004-10-09: this is needed if, for example, the compiler |
| 1544 | applied tail-call optimizations to main so that a function called |
| 1545 | from main returns directly to the caller of main. Since we don't |
| 1546 | stop at main, we should at least stop at the entry point of the |
| 1547 | application. */ |
| 1548 | if (!backtrace_past_entry |
| 1549 | && get_frame_type (this_frame) != DUMMY_FRAME && this_frame->level >= 0 |
| 1550 | && inside_entry_func (this_frame)) |
| 1551 | { |
| 1552 | frame_debug_got_null_frame (gdb_stdlog, this_frame, "inside entry func"); |
| 1553 | return NULL; |
| 1554 | } |
| 1555 | |
| 1556 | /* Assume that the only way to get a zero PC is through something |
| 1557 | like a SIGSEGV or a dummy frame, and hence that NORMAL frames |
| 1558 | will never unwind a zero PC. */ |
| 1559 | if (this_frame->level > 0 |
| 1560 | && get_frame_type (this_frame) == NORMAL_FRAME |
| 1561 | && get_frame_type (get_next_frame (this_frame)) == NORMAL_FRAME |
| 1562 | && get_frame_pc (this_frame) == 0) |
| 1563 | { |
| 1564 | frame_debug_got_null_frame (gdb_stdlog, this_frame, "zero PC"); |
| 1565 | return NULL; |
| 1566 | } |
| 1567 | |
| 1568 | return get_prev_frame_1 (this_frame); |
| 1569 | } |
| 1570 | |
| 1571 | CORE_ADDR |
| 1572 | get_frame_pc (struct frame_info *frame) |
| 1573 | { |
| 1574 | gdb_assert (frame->next != NULL); |
| 1575 | return frame_pc_unwind (frame->next); |
| 1576 | } |
| 1577 | |
| 1578 | /* Return an address that falls within THIS_FRAME's code block. */ |
| 1579 | |
| 1580 | CORE_ADDR |
| 1581 | get_frame_address_in_block (struct frame_info *this_frame) |
| 1582 | { |
| 1583 | /* A draft address. */ |
| 1584 | CORE_ADDR pc = get_frame_pc (this_frame); |
| 1585 | |
| 1586 | struct frame_info *next_frame = this_frame->next; |
| 1587 | |
| 1588 | /* Calling get_frame_pc returns the resume address for THIS_FRAME. |
| 1589 | Normally the resume address is inside the body of the function |
| 1590 | associated with THIS_FRAME, but there is a special case: when |
| 1591 | calling a function which the compiler knows will never return |
| 1592 | (for instance abort), the call may be the very last instruction |
| 1593 | in the calling function. The resume address will point after the |
| 1594 | call and may be at the beginning of a different function |
| 1595 | entirely. |
| 1596 | |
| 1597 | If THIS_FRAME is a signal frame or dummy frame, then we should |
| 1598 | not adjust the unwound PC. For a dummy frame, GDB pushed the |
| 1599 | resume address manually onto the stack. For a signal frame, the |
| 1600 | OS may have pushed the resume address manually and invoked the |
| 1601 | handler (e.g. GNU/Linux), or invoked the trampoline which called |
| 1602 | the signal handler - but in either case the signal handler is |
| 1603 | expected to return to the trampoline. So in both of these |
| 1604 | cases we know that the resume address is executable and |
| 1605 | related. So we only need to adjust the PC if THIS_FRAME |
| 1606 | is a normal function. |
| 1607 | |
| 1608 | If the program has been interrupted while THIS_FRAME is current, |
| 1609 | then clearly the resume address is inside the associated |
| 1610 | function. There are three kinds of interruption: debugger stop |
| 1611 | (next frame will be SENTINEL_FRAME), operating system |
| 1612 | signal or exception (next frame will be SIGTRAMP_FRAME), |
| 1613 | or debugger-induced function call (next frame will be |
| 1614 | DUMMY_FRAME). So we only need to adjust the PC if |
| 1615 | NEXT_FRAME is a normal function. |
| 1616 | |
| 1617 | We check the type of NEXT_FRAME first, since it is already |
| 1618 | known; frame type is determined by the unwinder, and since |
| 1619 | we have THIS_FRAME we've already selected an unwinder for |
| 1620 | NEXT_FRAME. */ |
| 1621 | if (get_frame_type (next_frame) == NORMAL_FRAME |
| 1622 | && get_frame_type (this_frame) == NORMAL_FRAME) |
| 1623 | return pc - 1; |
| 1624 | |
| 1625 | return pc; |
| 1626 | } |
| 1627 | |
| 1628 | static int |
| 1629 | pc_notcurrent (struct frame_info *frame) |
| 1630 | { |
| 1631 | /* If FRAME is not the innermost frame, that normally means that |
| 1632 | FRAME->pc points at the return instruction (which is *after* the |
| 1633 | call instruction), and we want to get the line containing the |
| 1634 | call (because the call is where the user thinks the program is). |
| 1635 | However, if the next frame is either a SIGTRAMP_FRAME or a |
| 1636 | DUMMY_FRAME, then the next frame will contain a saved interrupt |
| 1637 | PC and such a PC indicates the current (rather than next) |
| 1638 | instruction/line, consequently, for such cases, want to get the |
| 1639 | line containing fi->pc. */ |
| 1640 | struct frame_info *next = get_next_frame (frame); |
| 1641 | int notcurrent = (next != NULL && get_frame_type (next) == NORMAL_FRAME); |
| 1642 | return notcurrent; |
| 1643 | } |
| 1644 | |
| 1645 | void |
| 1646 | find_frame_sal (struct frame_info *frame, struct symtab_and_line *sal) |
| 1647 | { |
| 1648 | (*sal) = find_pc_line (get_frame_pc (frame), pc_notcurrent (frame)); |
| 1649 | } |
| 1650 | |
| 1651 | /* Per "frame.h", return the ``address'' of the frame. Code should |
| 1652 | really be using get_frame_id(). */ |
| 1653 | CORE_ADDR |
| 1654 | get_frame_base (struct frame_info *fi) |
| 1655 | { |
| 1656 | return get_frame_id (fi).stack_addr; |
| 1657 | } |
| 1658 | |
| 1659 | /* High-level offsets into the frame. Used by the debug info. */ |
| 1660 | |
| 1661 | CORE_ADDR |
| 1662 | get_frame_base_address (struct frame_info *fi) |
| 1663 | { |
| 1664 | if (get_frame_type (fi) != NORMAL_FRAME) |
| 1665 | return 0; |
| 1666 | if (fi->base == NULL) |
| 1667 | fi->base = frame_base_find_by_frame (fi); |
| 1668 | /* Sneaky: If the low-level unwind and high-level base code share a |
| 1669 | common unwinder, let them share the prologue cache. */ |
| 1670 | if (fi->base->unwind == fi->unwind) |
| 1671 | return fi->base->this_base (fi, &fi->prologue_cache); |
| 1672 | return fi->base->this_base (fi, &fi->base_cache); |
| 1673 | } |
| 1674 | |
| 1675 | CORE_ADDR |
| 1676 | get_frame_locals_address (struct frame_info *fi) |
| 1677 | { |
| 1678 | void **cache; |
| 1679 | if (get_frame_type (fi) != NORMAL_FRAME) |
| 1680 | return 0; |
| 1681 | /* If there isn't a frame address method, find it. */ |
| 1682 | if (fi->base == NULL) |
| 1683 | fi->base = frame_base_find_by_frame (fi); |
| 1684 | /* Sneaky: If the low-level unwind and high-level base code share a |
| 1685 | common unwinder, let them share the prologue cache. */ |
| 1686 | if (fi->base->unwind == fi->unwind) |
| 1687 | return fi->base->this_locals (fi, &fi->prologue_cache); |
| 1688 | return fi->base->this_locals (fi, &fi->base_cache); |
| 1689 | } |
| 1690 | |
| 1691 | CORE_ADDR |
| 1692 | get_frame_args_address (struct frame_info *fi) |
| 1693 | { |
| 1694 | void **cache; |
| 1695 | if (get_frame_type (fi) != NORMAL_FRAME) |
| 1696 | return 0; |
| 1697 | /* If there isn't a frame address method, find it. */ |
| 1698 | if (fi->base == NULL) |
| 1699 | fi->base = frame_base_find_by_frame (fi); |
| 1700 | /* Sneaky: If the low-level unwind and high-level base code share a |
| 1701 | common unwinder, let them share the prologue cache. */ |
| 1702 | if (fi->base->unwind == fi->unwind) |
| 1703 | return fi->base->this_args (fi, &fi->prologue_cache); |
| 1704 | return fi->base->this_args (fi, &fi->base_cache); |
| 1705 | } |
| 1706 | |
| 1707 | /* Level of the selected frame: 0 for innermost, 1 for its caller, ... |
| 1708 | or -1 for a NULL frame. */ |
| 1709 | |
| 1710 | int |
| 1711 | frame_relative_level (struct frame_info *fi) |
| 1712 | { |
| 1713 | if (fi == NULL) |
| 1714 | return -1; |
| 1715 | else |
| 1716 | return fi->level; |
| 1717 | } |
| 1718 | |
| 1719 | enum frame_type |
| 1720 | get_frame_type (struct frame_info *frame) |
| 1721 | { |
| 1722 | if (frame->unwind == NULL) |
| 1723 | /* Initialize the frame's unwinder because that's what |
| 1724 | provides the frame's type. */ |
| 1725 | frame->unwind = frame_unwind_find_by_frame (frame, &frame->prologue_cache); |
| 1726 | return frame->unwind->type; |
| 1727 | } |
| 1728 | |
| 1729 | void |
| 1730 | deprecated_update_frame_pc_hack (struct frame_info *frame, CORE_ADDR pc) |
| 1731 | { |
| 1732 | if (frame_debug) |
| 1733 | fprintf_unfiltered (gdb_stdlog, |
| 1734 | "{ deprecated_update_frame_pc_hack (frame=%d,pc=0x%s) }\n", |
| 1735 | frame->level, paddr_nz (pc)); |
| 1736 | /* NOTE: cagney/2003-03-11: Some architectures (e.g., Arm) are |
| 1737 | maintaining a locally allocated frame object. Since such frames |
| 1738 | are not in the frame chain, it isn't possible to assume that the |
| 1739 | frame has a next. Sigh. */ |
| 1740 | if (frame->next != NULL) |
| 1741 | { |
| 1742 | /* While we're at it, update this frame's cached PC value, found |
| 1743 | in the next frame. Oh for the day when "struct frame_info" |
| 1744 | is opaque and this hack on hack can just go away. */ |
| 1745 | frame->next->prev_pc.value = pc; |
| 1746 | frame->next->prev_pc.p = 1; |
| 1747 | } |
| 1748 | } |
| 1749 | |
| 1750 | void |
| 1751 | deprecated_update_frame_base_hack (struct frame_info *frame, CORE_ADDR base) |
| 1752 | { |
| 1753 | if (frame_debug) |
| 1754 | fprintf_unfiltered (gdb_stdlog, |
| 1755 | "{ deprecated_update_frame_base_hack (frame=%d,base=0x%s) }\n", |
| 1756 | frame->level, paddr_nz (base)); |
| 1757 | /* See comment in "frame.h". */ |
| 1758 | frame->this_id.value.stack_addr = base; |
| 1759 | } |
| 1760 | |
| 1761 | /* Memory access methods. */ |
| 1762 | |
| 1763 | void |
| 1764 | get_frame_memory (struct frame_info *this_frame, CORE_ADDR addr, |
| 1765 | gdb_byte *buf, int len) |
| 1766 | { |
| 1767 | read_memory (addr, buf, len); |
| 1768 | } |
| 1769 | |
| 1770 | LONGEST |
| 1771 | get_frame_memory_signed (struct frame_info *this_frame, CORE_ADDR addr, |
| 1772 | int len) |
| 1773 | { |
| 1774 | return read_memory_integer (addr, len); |
| 1775 | } |
| 1776 | |
| 1777 | ULONGEST |
| 1778 | get_frame_memory_unsigned (struct frame_info *this_frame, CORE_ADDR addr, |
| 1779 | int len) |
| 1780 | { |
| 1781 | return read_memory_unsigned_integer (addr, len); |
| 1782 | } |
| 1783 | |
| 1784 | int |
| 1785 | safe_frame_unwind_memory (struct frame_info *this_frame, |
| 1786 | CORE_ADDR addr, gdb_byte *buf, int len) |
| 1787 | { |
| 1788 | /* NOTE: target_read_memory returns zero on success! */ |
| 1789 | return !target_read_memory (addr, buf, len); |
| 1790 | } |
| 1791 | |
| 1792 | /* Architecture method. */ |
| 1793 | |
| 1794 | struct gdbarch * |
| 1795 | get_frame_arch (struct frame_info *this_frame) |
| 1796 | { |
| 1797 | return current_gdbarch; |
| 1798 | } |
| 1799 | |
| 1800 | /* Stack pointer methods. */ |
| 1801 | |
| 1802 | CORE_ADDR |
| 1803 | get_frame_sp (struct frame_info *this_frame) |
| 1804 | { |
| 1805 | struct gdbarch *gdbarch = get_frame_arch (this_frame); |
| 1806 | /* Normality - an architecture that provides a way of obtaining any |
| 1807 | frame inner-most address. */ |
| 1808 | if (gdbarch_unwind_sp_p (gdbarch)) |
| 1809 | /* NOTE drow/2008-06-28: gdbarch_unwind_sp could be converted to |
| 1810 | operate on THIS_FRAME now. */ |
| 1811 | return gdbarch_unwind_sp (gdbarch, this_frame->next); |
| 1812 | /* Now things are really are grim. Hope that the value returned by |
| 1813 | the gdbarch_sp_regnum register is meaningful. */ |
| 1814 | if (gdbarch_sp_regnum (gdbarch) >= 0) |
| 1815 | return get_frame_register_unsigned (this_frame, |
| 1816 | gdbarch_sp_regnum (gdbarch)); |
| 1817 | internal_error (__FILE__, __LINE__, _("Missing unwind SP method")); |
| 1818 | } |
| 1819 | |
| 1820 | /* Return the reason why we can't unwind past FRAME. */ |
| 1821 | |
| 1822 | enum unwind_stop_reason |
| 1823 | get_frame_unwind_stop_reason (struct frame_info *frame) |
| 1824 | { |
| 1825 | /* If we haven't tried to unwind past this point yet, then assume |
| 1826 | that unwinding would succeed. */ |
| 1827 | if (frame->prev_p == 0) |
| 1828 | return UNWIND_NO_REASON; |
| 1829 | |
| 1830 | /* Otherwise, we set a reason when we succeeded (or failed) to |
| 1831 | unwind. */ |
| 1832 | return frame->stop_reason; |
| 1833 | } |
| 1834 | |
| 1835 | /* Return a string explaining REASON. */ |
| 1836 | |
| 1837 | const char * |
| 1838 | frame_stop_reason_string (enum unwind_stop_reason reason) |
| 1839 | { |
| 1840 | switch (reason) |
| 1841 | { |
| 1842 | case UNWIND_NULL_ID: |
| 1843 | return _("unwinder did not report frame ID"); |
| 1844 | |
| 1845 | case UNWIND_INNER_ID: |
| 1846 | return _("previous frame inner to this frame (corrupt stack?)"); |
| 1847 | |
| 1848 | case UNWIND_SAME_ID: |
| 1849 | return _("previous frame identical to this frame (corrupt stack?)"); |
| 1850 | |
| 1851 | case UNWIND_NO_SAVED_PC: |
| 1852 | return _("frame did not save the PC"); |
| 1853 | |
| 1854 | case UNWIND_NO_REASON: |
| 1855 | case UNWIND_FIRST_ERROR: |
| 1856 | default: |
| 1857 | internal_error (__FILE__, __LINE__, |
| 1858 | "Invalid frame stop reason"); |
| 1859 | } |
| 1860 | } |
| 1861 | |
| 1862 | /* Clean up after a failed (wrong unwinder) attempt to unwind past |
| 1863 | FRAME. */ |
| 1864 | |
| 1865 | static void |
| 1866 | frame_cleanup_after_sniffer (void *arg) |
| 1867 | { |
| 1868 | struct frame_info *frame = arg; |
| 1869 | |
| 1870 | /* The sniffer should not allocate a prologue cache if it did not |
| 1871 | match this frame. */ |
| 1872 | gdb_assert (frame->prologue_cache == NULL); |
| 1873 | |
| 1874 | /* No sniffer should extend the frame chain; sniff based on what is |
| 1875 | already certain. */ |
| 1876 | gdb_assert (!frame->prev_p); |
| 1877 | |
| 1878 | /* The sniffer should not check the frame's ID; that's circular. */ |
| 1879 | gdb_assert (!frame->this_id.p); |
| 1880 | |
| 1881 | /* Clear cached fields dependent on the unwinder. |
| 1882 | |
| 1883 | The previous PC is independent of the unwinder, but the previous |
| 1884 | function is not (see get_frame_address_in_block). */ |
| 1885 | frame->prev_func.p = 0; |
| 1886 | frame->prev_func.addr = 0; |
| 1887 | |
| 1888 | /* Discard the unwinder last, so that we can easily find it if an assertion |
| 1889 | in this function triggers. */ |
| 1890 | frame->unwind = NULL; |
| 1891 | } |
| 1892 | |
| 1893 | /* Set FRAME's unwinder temporarily, so that we can call a sniffer. |
| 1894 | Return a cleanup which should be called if unwinding fails, and |
| 1895 | discarded if it succeeds. */ |
| 1896 | |
| 1897 | struct cleanup * |
| 1898 | frame_prepare_for_sniffer (struct frame_info *frame, |
| 1899 | const struct frame_unwind *unwind) |
| 1900 | { |
| 1901 | gdb_assert (frame->unwind == NULL); |
| 1902 | frame->unwind = unwind; |
| 1903 | return make_cleanup (frame_cleanup_after_sniffer, frame); |
| 1904 | } |
| 1905 | |
| 1906 | extern initialize_file_ftype _initialize_frame; /* -Wmissing-prototypes */ |
| 1907 | |
| 1908 | static struct cmd_list_element *set_backtrace_cmdlist; |
| 1909 | static struct cmd_list_element *show_backtrace_cmdlist; |
| 1910 | |
| 1911 | static void |
| 1912 | set_backtrace_cmd (char *args, int from_tty) |
| 1913 | { |
| 1914 | help_list (set_backtrace_cmdlist, "set backtrace ", -1, gdb_stdout); |
| 1915 | } |
| 1916 | |
| 1917 | static void |
| 1918 | show_backtrace_cmd (char *args, int from_tty) |
| 1919 | { |
| 1920 | cmd_show_list (show_backtrace_cmdlist, from_tty, ""); |
| 1921 | } |
| 1922 | |
| 1923 | void |
| 1924 | _initialize_frame (void) |
| 1925 | { |
| 1926 | obstack_init (&frame_cache_obstack); |
| 1927 | |
| 1928 | observer_attach_target_changed (frame_observer_target_changed); |
| 1929 | |
| 1930 | add_prefix_cmd ("backtrace", class_maintenance, set_backtrace_cmd, _("\ |
| 1931 | Set backtrace specific variables.\n\ |
| 1932 | Configure backtrace variables such as the backtrace limit"), |
| 1933 | &set_backtrace_cmdlist, "set backtrace ", |
| 1934 | 0/*allow-unknown*/, &setlist); |
| 1935 | add_prefix_cmd ("backtrace", class_maintenance, show_backtrace_cmd, _("\ |
| 1936 | Show backtrace specific variables\n\ |
| 1937 | Show backtrace variables such as the backtrace limit"), |
| 1938 | &show_backtrace_cmdlist, "show backtrace ", |
| 1939 | 0/*allow-unknown*/, &showlist); |
| 1940 | |
| 1941 | add_setshow_boolean_cmd ("past-main", class_obscure, |
| 1942 | &backtrace_past_main, _("\ |
| 1943 | Set whether backtraces should continue past \"main\"."), _("\ |
| 1944 | Show whether backtraces should continue past \"main\"."), _("\ |
| 1945 | Normally the caller of \"main\" is not of interest, so GDB will terminate\n\ |
| 1946 | the backtrace at \"main\". Set this variable if you need to see the rest\n\ |
| 1947 | of the stack trace."), |
| 1948 | NULL, |
| 1949 | show_backtrace_past_main, |
| 1950 | &set_backtrace_cmdlist, |
| 1951 | &show_backtrace_cmdlist); |
| 1952 | |
| 1953 | add_setshow_boolean_cmd ("past-entry", class_obscure, |
| 1954 | &backtrace_past_entry, _("\ |
| 1955 | Set whether backtraces should continue past the entry point of a program."), |
| 1956 | _("\ |
| 1957 | Show whether backtraces should continue past the entry point of a program."), |
| 1958 | _("\ |
| 1959 | Normally there are no callers beyond the entry point of a program, so GDB\n\ |
| 1960 | will terminate the backtrace there. Set this variable if you need to see \n\ |
| 1961 | the rest of the stack trace."), |
| 1962 | NULL, |
| 1963 | show_backtrace_past_entry, |
| 1964 | &set_backtrace_cmdlist, |
| 1965 | &show_backtrace_cmdlist); |
| 1966 | |
| 1967 | add_setshow_integer_cmd ("limit", class_obscure, |
| 1968 | &backtrace_limit, _("\ |
| 1969 | Set an upper bound on the number of backtrace levels."), _("\ |
| 1970 | Show the upper bound on the number of backtrace levels."), _("\ |
| 1971 | No more than the specified number of frames can be displayed or examined.\n\ |
| 1972 | Zero is unlimited."), |
| 1973 | NULL, |
| 1974 | show_backtrace_limit, |
| 1975 | &set_backtrace_cmdlist, |
| 1976 | &show_backtrace_cmdlist); |
| 1977 | |
| 1978 | /* Debug this files internals. */ |
| 1979 | add_setshow_zinteger_cmd ("frame", class_maintenance, &frame_debug, _("\ |
| 1980 | Set frame debugging."), _("\ |
| 1981 | Show frame debugging."), _("\ |
| 1982 | When non-zero, frame specific internal debugging is enabled."), |
| 1983 | NULL, |
| 1984 | show_frame_debug, |
| 1985 | &setdebuglist, &showdebuglist); |
| 1986 | } |