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, 2004 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 "user-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/* We keep a cache of stack frames, each of which is a "struct 44 frame_info". The innermost one gets allocated (in 45 wait_for_inferior) each time the inferior stops; current_frame 46 points to it. Additional frames get allocated (in get_prev_frame) 47 as needed, and are chained through the next and prev fields. Any 48 time that the frame cache becomes invalid (most notably when we 49 execute something, but also if we change how we interpret the 50 frames (e.g. "set heuristic-fence-post" in mips-tdep.c, or anything 51 which reads new symbols)), we should call reinit_frame_cache. */ 52 53struct frame_info 54{ 55 /* Level of this frame. The inner-most (youngest) frame is at level 56 0. As you move towards the outer-most (oldest) frame, the level 57 increases. This is a cached value. It could just as easily be 58 computed by counting back from the selected frame to the inner 59 most frame. */ 60 /* NOTE: cagney/2002-04-05: Perhaphs a level of ``-1'' should be 61 reserved to indicate a bogus frame - one that has been created 62 just to keep GDB happy (GDB always needs a frame). For the 63 moment leave this as speculation. */ 64 int level; 65 66 /* The frame's type. */ 67 /* FIXME: cagney/2003-04-02: Should instead be returning 68 ->unwind->type. Unfortunately, legacy code is still explicitly 69 setting the type using the method deprecated_set_frame_type. 70 Eliminate that method and this field can be eliminated. */ 71 enum frame_type type; 72 73 /* For each register, address of where it was saved on entry to the 74 frame, or zero if it was not saved on entry to this frame. This 75 includes special registers such as pc and fp saved in special 76 ways in the stack frame. The SP_REGNUM is even more special, the 77 address here is the sp for the previous frame, not the address 78 where the sp was saved. */ 79 /* Allocated by frame_saved_regs_zalloc () which is called / 80 initialized by DEPRECATED_FRAME_INIT_SAVED_REGS(). */ 81 CORE_ADDR *saved_regs; /*NUM_REGS + NUM_PSEUDO_REGS*/ 82 83 /* Anything extra for this structure that may have been defined in 84 the machine dependent files. */ 85 /* Allocated by frame_extra_info_zalloc () which is called / 86 initialized by DEPRECATED_INIT_EXTRA_FRAME_INFO */ 87 struct frame_extra_info *extra_info; 88 89 /* The frame's low-level unwinder and corresponding cache. The 90 low-level unwinder is responsible for unwinding register values 91 for the previous frame. The low-level unwind methods are 92 selected based on the presence, or otherwize, of register unwind 93 information such as CFI. */ 94 void *prologue_cache; 95 const struct frame_unwind *unwind; 96 97 /* Cached copy of the previous frame's resume address. */ 98 struct { 99 int p; 100 CORE_ADDR value; 101 } prev_pc; 102 103 /* Cached copy of the previous frame's function address. */ 104 struct 105 { 106 CORE_ADDR addr; 107 int p; 108 } prev_func; 109 110 /* This frame's ID. */ 111 struct 112 { 113 int p; 114 struct frame_id value; 115 } this_id; 116 117 /* The frame's high-level base methods, and corresponding cache. 118 The high level base methods are selected based on the frame's 119 debug info. */ 120 const struct frame_base *base; 121 void *base_cache; 122 123 /* Pointers to the next (down, inner, younger) and previous (up, 124 outer, older) frame_info's in the frame cache. */ 125 struct frame_info *next; /* down, inner, younger */ 126 int prev_p; 127 struct frame_info *prev; /* up, outer, older */ 128}; 129 130/* Flag to control debugging. */ 131 132static int frame_debug; 133 134/* Flag to indicate whether backtraces should stop at main et.al. */ 135 136static int backtrace_past_main; 137static unsigned int backtrace_limit = UINT_MAX; 138 139int (*frame_tdep_pc_fixup)(CORE_ADDR *pc); 140 141void 142fprint_frame_id (struct ui_file *file, struct frame_id id) 143{ 144 fprintf_unfiltered (file, "{stack=0x%s,code=0x%s,special=0x%s}", 145 paddr_nz (id.stack_addr), 146 paddr_nz (id.code_addr), 147 paddr_nz (id.special_addr)); 148} 149 150static void 151fprint_frame_type (struct ui_file *file, enum frame_type type) 152{ 153 switch (type) 154 { 155 case UNKNOWN_FRAME: 156 fprintf_unfiltered (file, "UNKNOWN_FRAME"); 157 return; 158 case NORMAL_FRAME: 159 fprintf_unfiltered (file, "NORMAL_FRAME"); 160 return; 161 case DUMMY_FRAME: 162 fprintf_unfiltered (file, "DUMMY_FRAME"); 163 return; 164 case SIGTRAMP_FRAME: 165 fprintf_unfiltered (file, "SIGTRAMP_FRAME"); 166 return; 167 default: 168 fprintf_unfiltered (file, "<unknown type>"); 169 return; 170 }; 171} 172 173static void 174fprint_frame (struct ui_file *file, struct frame_info *fi) 175{ 176 if (fi == NULL) 177 { 178 fprintf_unfiltered (file, "<NULL frame>"); 179 return; 180 } 181 fprintf_unfiltered (file, "{"); 182 fprintf_unfiltered (file, "level=%d", fi->level); 183 fprintf_unfiltered (file, ","); 184 fprintf_unfiltered (file, "type="); 185 fprint_frame_type (file, fi->type); 186 fprintf_unfiltered (file, ","); 187 fprintf_unfiltered (file, "unwind="); 188 if (fi->unwind != NULL) 189 gdb_print_host_address (fi->unwind, file); 190 else 191 fprintf_unfiltered (file, "<unknown>"); 192 fprintf_unfiltered (file, ","); 193 fprintf_unfiltered (file, "pc="); 194 if (fi->next != NULL && fi->next->prev_pc.p) 195 fprintf_unfiltered (file, "0x%s", paddr_nz (fi->next->prev_pc.value)); 196 else 197 fprintf_unfiltered (file, "<unknown>"); 198 fprintf_unfiltered (file, ","); 199 fprintf_unfiltered (file, "id="); 200 if (fi->this_id.p) 201 fprint_frame_id (file, fi->this_id.value); 202 else 203 fprintf_unfiltered (file, "<unknown>"); 204 fprintf_unfiltered (file, ","); 205 fprintf_unfiltered (file, "func="); 206 if (fi->next != NULL && fi->next->prev_func.p) 207 fprintf_unfiltered (file, "0x%s", paddr_nz (fi->next->prev_func.addr)); 208 else 209 fprintf_unfiltered (file, "<unknown>"); 210 fprintf_unfiltered (file, "}"); 211} 212 213/* Return a frame uniq ID that can be used to, later, re-find the 214 frame. */ 215 216struct frame_id 217get_frame_id (struct frame_info *fi) 218{ 219 if (fi == NULL) 220 { 221 return null_frame_id; 222 } 223 if (!fi->this_id.p) 224 { 225 gdb_assert (!legacy_frame_p (current_gdbarch)); 226 if (frame_debug) 227 fprintf_unfiltered (gdb_stdlog, "{ get_frame_id (fi=%d) ", 228 fi->level); 229 /* Find the unwinder. */ 230 if (fi->unwind == NULL) 231 { 232 fi->unwind = frame_unwind_find_by_frame (fi->next); 233 /* FIXME: cagney/2003-04-02: Rather than storing the frame's 234 type in the frame, the unwinder's type should be returned 235 directly. Unfortunately, legacy code, called by 236 legacy_get_prev_frame, explicitly set the frames type 237 using the method deprecated_set_frame_type(). */ 238 fi->type = fi->unwind->type; 239 } 240 /* Find THIS frame's ID. */ 241 fi->unwind->this_id (fi->next, &fi->prologue_cache, &fi->this_id.value); 242 fi->this_id.p = 1; 243 if (frame_debug) 244 { 245 fprintf_unfiltered (gdb_stdlog, "-> "); 246 fprint_frame_id (gdb_stdlog, fi->this_id.value); 247 fprintf_unfiltered (gdb_stdlog, " }\n"); 248 } 249 } 250 return fi->this_id.value; 251} 252 253const struct frame_id null_frame_id; /* All zeros. */ 254 255struct frame_id 256frame_id_build_special (CORE_ADDR stack_addr, CORE_ADDR code_addr, 257 CORE_ADDR special_addr) 258{ 259 struct frame_id id; 260 id.stack_addr = stack_addr; 261 id.code_addr = code_addr; 262 id.special_addr = special_addr; 263 return id; 264} 265 266struct frame_id 267frame_id_build (CORE_ADDR stack_addr, CORE_ADDR code_addr) 268{ 269 return frame_id_build_special (stack_addr, code_addr, 0); 270} 271 272int 273frame_id_p (struct frame_id l) 274{ 275 int p; 276 /* The .code can be NULL but the .stack cannot. */ 277 p = (l.stack_addr != 0); 278 if (frame_debug) 279 { 280 fprintf_unfiltered (gdb_stdlog, "{ frame_id_p (l="); 281 fprint_frame_id (gdb_stdlog, l); 282 fprintf_unfiltered (gdb_stdlog, ") -> %d }\n", p); 283 } 284 return p; 285} 286 287int 288frame_id_eq (struct frame_id l, struct frame_id r) 289{ 290 int eq; 291 if (l.stack_addr == 0 || r.stack_addr == 0) 292 /* Like a NaN, if either ID is invalid, the result is false. */ 293 eq = 0; 294 else if (l.stack_addr != r.stack_addr) 295 /* If .stack addresses are different, the frames are different. */ 296 eq = 0; 297 else if (l.code_addr == 0 || r.code_addr == 0) 298 /* A zero code addr is a wild card, always succeed. */ 299 eq = 1; 300 else if (l.code_addr != r.code_addr) 301 /* If .code addresses are different, the frames are different. */ 302 eq = 0; 303 else if (l.special_addr == 0 || r.special_addr == 0) 304 /* A zero special addr is a wild card (or unused), always succeed. */ 305 eq = 1; 306 else if (l.special_addr == r.special_addr) 307 /* Frames are equal. */ 308 eq = 1; 309 else 310 /* No luck. */ 311 eq = 0; 312 if (frame_debug) 313 { 314 fprintf_unfiltered (gdb_stdlog, "{ frame_id_eq (l="); 315 fprint_frame_id (gdb_stdlog, l); 316 fprintf_unfiltered (gdb_stdlog, ",r="); 317 fprint_frame_id (gdb_stdlog, r); 318 fprintf_unfiltered (gdb_stdlog, ") -> %d }\n", eq); 319 } 320 return eq; 321} 322 323int 324frame_id_inner (struct frame_id l, struct frame_id r) 325{ 326 int inner; 327 if (l.stack_addr == 0 || r.stack_addr == 0) 328 /* Like NaN, any operation involving an invalid ID always fails. */ 329 inner = 0; 330 else 331 /* Only return non-zero when strictly inner than. Note that, per 332 comment in "frame.h", there is some fuzz here. Frameless 333 functions are not strictly inner than (same .stack but 334 different .code and/or .special address). */ 335 inner = INNER_THAN (l.stack_addr, r.stack_addr); 336 if (frame_debug) 337 { 338 fprintf_unfiltered (gdb_stdlog, "{ frame_id_inner (l="); 339 fprint_frame_id (gdb_stdlog, l); 340 fprintf_unfiltered (gdb_stdlog, ",r="); 341 fprint_frame_id (gdb_stdlog, r); 342 fprintf_unfiltered (gdb_stdlog, ") -> %d }\n", inner); 343 } 344 return inner; 345} 346 347struct frame_info * 348frame_find_by_id (struct frame_id id) 349{ 350 struct frame_info *frame; 351 352 /* ZERO denotes the null frame, let the caller decide what to do 353 about it. Should it instead return get_current_frame()? */ 354 if (!frame_id_p (id)) 355 return NULL; 356 357 for (frame = get_current_frame (); 358 frame != NULL; 359 frame = get_prev_frame (frame)) 360 { 361 struct frame_id this = get_frame_id (frame); 362 if (frame_id_eq (id, this)) 363 /* An exact match. */ 364 return frame; 365 if (frame_id_inner (id, this)) 366 /* Gone to far. */ 367 return NULL; 368 /* Either, we're not yet gone far enough out along the frame 369 chain (inner(this,id), or we're comparing frameless functions 370 (same .base, different .func, no test available). Struggle 371 on until we've definitly gone to far. */ 372 } 373 return NULL; 374} 375 376CORE_ADDR 377frame_pc_unwind (struct frame_info *this_frame) 378{ 379 if (!this_frame->prev_pc.p) 380 { 381 CORE_ADDR pc; 382 if (gdbarch_unwind_pc_p (current_gdbarch)) 383 { 384 /* The right way. The `pure' way. The one true way. This 385 method depends solely on the register-unwind code to 386 determine the value of registers in THIS frame, and hence 387 the value of this frame's PC (resume address). A typical 388 implementation is no more than: 389 390 frame_unwind_register (this_frame, ISA_PC_REGNUM, buf); 391 return extract_unsigned_integer (buf, size of ISA_PC_REGNUM); 392 393 Note: this method is very heavily dependent on a correct 394 register-unwind implementation, it pays to fix that 395 method first; this method is frame type agnostic, since 396 it only deals with register values, it works with any 397 frame. This is all in stark contrast to the old 398 FRAME_SAVED_PC which would try to directly handle all the 399 different ways that a PC could be unwound. */ 400 pc = gdbarch_unwind_pc (current_gdbarch, this_frame); 401 } 402 else if (this_frame->level < 0) 403 { 404 /* FIXME: cagney/2003-03-06: Old code and and a sentinel 405 frame. Do like was always done. Fetch the PC's value 406 direct from the global registers array (via read_pc). 407 This assumes that this frame belongs to the current 408 global register cache. The assumption is dangerous. */ 409 pc = read_pc (); 410 } 411 else if (DEPRECATED_FRAME_SAVED_PC_P ()) 412 { 413 /* FIXME: cagney/2003-03-06: Old code, but not a sentinel 414 frame. Do like was always done. Note that this method, 415 unlike unwind_pc(), tries to handle all the different 416 frame cases directly. It fails. */ 417 pc = DEPRECATED_FRAME_SAVED_PC (this_frame); 418 } 419 else 420 internal_error (__FILE__, __LINE__, "No gdbarch_unwind_pc method"); 421 this_frame->prev_pc.value = pc; 422 this_frame->prev_pc.p = 1; 423 if (frame_debug) 424 fprintf_unfiltered (gdb_stdlog, 425 "{ frame_pc_unwind (this_frame=%d) -> 0x%s }\n", 426 this_frame->level, 427 paddr_nz (this_frame->prev_pc.value)); 428 } 429 return this_frame->prev_pc.value; 430} 431 432CORE_ADDR 433frame_func_unwind (struct frame_info *fi) 434{ 435 if (!fi->prev_func.p) 436 { 437 /* Make certain that this, and not the adjacent, function is 438 found. */ 439 CORE_ADDR addr_in_block = frame_unwind_address_in_block (fi); 440 fi->prev_func.p = 1; 441 fi->prev_func.addr = get_pc_function_start (addr_in_block); 442 if (frame_debug) 443 fprintf_unfiltered (gdb_stdlog, 444 "{ frame_func_unwind (fi=%d) -> 0x%s }\n", 445 fi->level, paddr_nz (fi->prev_func.addr)); 446 } 447 return fi->prev_func.addr; 448} 449 450CORE_ADDR 451get_frame_func (struct frame_info *fi) 452{ 453 return frame_func_unwind (fi->next); 454} 455 456static int 457do_frame_unwind_register (void *src, int regnum, void *buf) 458{ 459 frame_unwind_register (src, regnum, buf); 460 return 1; 461} 462 463void 464frame_pop (struct frame_info *this_frame) 465{ 466 struct regcache *scratch_regcache; 467 struct cleanup *cleanups; 468 469 if (DEPRECATED_POP_FRAME_P ()) 470 { 471 /* A legacy architecture that has implemented a custom pop 472 function. All new architectures should instead be using the 473 generic code below. */ 474 DEPRECATED_POP_FRAME; 475 } 476 else 477 { 478 /* Make a copy of all the register values unwound from this 479 frame. Save them in a scratch buffer so that there isn't a 480 race betweening trying to extract the old values from the 481 current_regcache while, at the same time writing new values 482 into that same cache. */ 483 struct regcache *scratch = regcache_xmalloc (current_gdbarch); 484 struct cleanup *cleanups = make_cleanup_regcache_xfree (scratch); 485 regcache_save (scratch, do_frame_unwind_register, this_frame); 486 /* FIXME: cagney/2003-03-16: It should be possible to tell the 487 target's register cache that it is about to be hit with a 488 burst register transfer and that the sequence of register 489 writes should be batched. The pair target_prepare_to_store() 490 and target_store_registers() kind of suggest this 491 functionality. Unfortunately, they don't implement it. Their 492 lack of a formal definition can lead to targets writing back 493 bogus values (arguably a bug in the target code mind). */ 494 /* Now copy those saved registers into the current regcache. 495 Here, regcache_cpy() calls regcache_restore(). */ 496 regcache_cpy (current_regcache, scratch); 497 do_cleanups (cleanups); 498 } 499 /* We've made right mess of GDB's local state, just discard 500 everything. */ 501 flush_cached_frames (); 502} 503 504void 505frame_register_unwind (struct frame_info *frame, int regnum, 506 int *optimizedp, enum lval_type *lvalp, 507 CORE_ADDR *addrp, int *realnump, void *bufferp) 508{ 509 struct frame_unwind_cache *cache; 510 511 if (frame_debug) 512 { 513 fprintf_unfiltered (gdb_stdlog, "\ 514{ frame_register_unwind (frame=%d,regnum=%d(%s),...) ", 515 frame->level, regnum, 516 frame_map_regnum_to_name (frame, regnum)); 517 } 518 519 /* Require all but BUFFERP to be valid. A NULL BUFFERP indicates 520 that the value proper does not need to be fetched. */ 521 gdb_assert (optimizedp != NULL); 522 gdb_assert (lvalp != NULL); 523 gdb_assert (addrp != NULL); 524 gdb_assert (realnump != NULL); 525 /* gdb_assert (bufferp != NULL); */ 526 527 /* NOTE: cagney/2002-11-27: A program trying to unwind a NULL frame 528 is broken. There is always a frame. If there, for some reason, 529 isn't, there is some pretty busted code as it should have 530 detected the problem before calling here. */ 531 gdb_assert (frame != NULL); 532 533 /* Find the unwinder. */ 534 if (frame->unwind == NULL) 535 { 536 frame->unwind = frame_unwind_find_by_frame (frame->next); 537 /* FIXME: cagney/2003-04-02: Rather than storing the frame's 538 type in the frame, the unwinder's type should be returned 539 directly. Unfortunately, legacy code, called by 540 legacy_get_prev_frame, explicitly set the frames type using 541 the method deprecated_set_frame_type(). */ 542 frame->type = frame->unwind->type; 543 } 544 545 /* Ask this frame to unwind its register. See comment in 546 "frame-unwind.h" for why NEXT frame and this unwind cace are 547 passed in. */ 548 frame->unwind->prev_register (frame->next, &frame->prologue_cache, regnum, 549 optimizedp, lvalp, addrp, realnump, bufferp); 550 551 if (frame_debug) 552 { 553 fprintf_unfiltered (gdb_stdlog, "->"); 554 fprintf_unfiltered (gdb_stdlog, " *optimizedp=%d", (*optimizedp)); 555 fprintf_unfiltered (gdb_stdlog, " *lvalp=%d", (int) (*lvalp)); 556 fprintf_unfiltered (gdb_stdlog, " *addrp=0x%s", paddr_nz ((*addrp))); 557 fprintf_unfiltered (gdb_stdlog, " *bufferp="); 558 if (bufferp == NULL) 559 fprintf_unfiltered (gdb_stdlog, "<NULL>"); 560 else 561 { 562 int i; 563 const unsigned char *buf = bufferp; 564 fprintf_unfiltered (gdb_stdlog, "["); 565 for (i = 0; i < register_size (current_gdbarch, regnum); i++) 566 fprintf_unfiltered (gdb_stdlog, "%02x", buf[i]); 567 fprintf_unfiltered (gdb_stdlog, "]"); 568 } 569 fprintf_unfiltered (gdb_stdlog, " }\n"); 570 } 571} 572 573void 574frame_register (struct frame_info *frame, int regnum, 575 int *optimizedp, enum lval_type *lvalp, 576 CORE_ADDR *addrp, int *realnump, void *bufferp) 577{ 578 /* Require all but BUFFERP to be valid. A NULL BUFFERP indicates 579 that the value proper does not need to be fetched. */ 580 gdb_assert (optimizedp != NULL); 581 gdb_assert (lvalp != NULL); 582 gdb_assert (addrp != NULL); 583 gdb_assert (realnump != NULL); 584 /* gdb_assert (bufferp != NULL); */ 585 586 /* Ulgh! Old code that, for lval_register, sets ADDRP to the offset 587 of the register in the register cache. It should instead return 588 the REGNUM corresponding to that register. Translate the . */ 589 if (DEPRECATED_GET_SAVED_REGISTER_P ()) 590 { 591 DEPRECATED_GET_SAVED_REGISTER (bufferp, optimizedp, addrp, frame, 592 regnum, lvalp); 593 /* Compute the REALNUM if the caller wants it. */ 594 if (*lvalp == lval_register) 595 { 596 int regnum; 597 for (regnum = 0; regnum < NUM_REGS + NUM_PSEUDO_REGS; regnum++) 598 { 599 if (*addrp == register_offset_hack (current_gdbarch, regnum)) 600 { 601 *realnump = regnum; 602 return; 603 } 604 } 605 internal_error (__FILE__, __LINE__, 606 "Failed to compute the register number corresponding" 607 " to 0x%s", paddr_d (*addrp)); 608 } 609 *realnump = -1; 610 return; 611 } 612 613 /* Obtain the register value by unwinding the register from the next 614 (more inner frame). */ 615 gdb_assert (frame != NULL && frame->next != NULL); 616 frame_register_unwind (frame->next, regnum, optimizedp, lvalp, addrp, 617 realnump, bufferp); 618} 619 620void 621frame_unwind_register (struct frame_info *frame, int regnum, void *buf) 622{ 623 int optimized; 624 CORE_ADDR addr; 625 int realnum; 626 enum lval_type lval; 627 frame_register_unwind (frame, regnum, &optimized, &lval, &addr, 628 &realnum, buf); 629} 630 631void 632get_frame_register (struct frame_info *frame, 633 int regnum, void *buf) 634{ 635 frame_unwind_register (frame->next, regnum, buf); 636} 637 638LONGEST 639frame_unwind_register_signed (struct frame_info *frame, int regnum) 640{ 641 char buf[MAX_REGISTER_SIZE]; 642 frame_unwind_register (frame, regnum, buf); 643 return extract_signed_integer (buf, DEPRECATED_REGISTER_VIRTUAL_SIZE (regnum)); 644} 645 646LONGEST 647get_frame_register_signed (struct frame_info *frame, int regnum) 648{ 649 return frame_unwind_register_signed (frame->next, regnum); 650} 651 652ULONGEST 653frame_unwind_register_unsigned (struct frame_info *frame, int regnum) 654{ 655 char buf[MAX_REGISTER_SIZE]; 656 frame_unwind_register (frame, regnum, buf); 657 return extract_unsigned_integer (buf, DEPRECATED_REGISTER_VIRTUAL_SIZE (regnum)); 658} 659 660ULONGEST 661get_frame_register_unsigned (struct frame_info *frame, int regnum) 662{ 663 return frame_unwind_register_unsigned (frame->next, regnum); 664} 665 666void 667frame_unwind_unsigned_register (struct frame_info *frame, int regnum, 668 ULONGEST *val) 669{ 670 char buf[MAX_REGISTER_SIZE]; 671 frame_unwind_register (frame, regnum, buf); 672 (*val) = extract_unsigned_integer (buf, DEPRECATED_REGISTER_VIRTUAL_SIZE (regnum)); 673} 674 675void 676put_frame_register (struct frame_info *frame, int regnum, const void *buf) 677{ 678 struct gdbarch *gdbarch = get_frame_arch (frame); 679 int realnum; 680 int optim; 681 enum lval_type lval; 682 CORE_ADDR addr; 683 frame_register (frame, regnum, &optim, &lval, &addr, &realnum, NULL); 684 if (optim) 685 error ("Attempt to assign to a value that was optimized out."); 686 switch (lval) 687 { 688 case lval_memory: 689 { 690 /* FIXME: write_memory doesn't yet take constant buffers. 691 Arrrg! */ 692 char tmp[MAX_REGISTER_SIZE]; 693 memcpy (tmp, buf, register_size (gdbarch, regnum)); 694 write_memory (addr, tmp, register_size (gdbarch, regnum)); 695 break; 696 } 697 case lval_register: 698 regcache_cooked_write (current_regcache, realnum, buf); 699 break; 700 default: 701 error ("Attempt to assign to an unmodifiable value."); 702 } 703} 704 705/* frame_register_read () 706 707 Find and return the value of REGNUM for the specified stack frame. 708 The number of bytes copied is DEPRECATED_REGISTER_RAW_SIZE 709 (REGNUM). 710 711 Returns 0 if the register value could not be found. */ 712 713int 714frame_register_read (struct frame_info *frame, int regnum, void *myaddr) 715{ 716 int optimized; 717 enum lval_type lval; 718 CORE_ADDR addr; 719 int realnum; 720 frame_register (frame, regnum, &optimized, &lval, &addr, &realnum, myaddr); 721 722 /* FIXME: cagney/2002-05-15: This test, is just bogus. 723 724 It indicates that the target failed to supply a value for a 725 register because it was "not available" at this time. Problem 726 is, the target still has the register and so get saved_register() 727 may be returning a value saved on the stack. */ 728 729 if (register_cached (regnum) < 0) 730 return 0; /* register value not available */ 731 732 return !optimized; 733} 734 735 736/* Map between a frame register number and its name. A frame register 737 space is a superset of the cooked register space --- it also 738 includes builtin registers. */ 739 740int 741frame_map_name_to_regnum (struct frame_info *frame, const char *name, int len) 742{ 743 return user_reg_map_name_to_regnum (get_frame_arch (frame), name, len); 744} 745 746const char * 747frame_map_regnum_to_name (struct frame_info *frame, int regnum) 748{ 749 return user_reg_map_regnum_to_name (get_frame_arch (frame), regnum); 750} 751 752/* Create a sentinel frame. */ 753 754static struct frame_info * 755create_sentinel_frame (struct regcache *regcache) 756{ 757 struct frame_info *frame = FRAME_OBSTACK_ZALLOC (struct frame_info); 758 frame->type = NORMAL_FRAME; 759 frame->level = -1; 760 /* Explicitly initialize the sentinel frame's cache. Provide it 761 with the underlying regcache. In the future additional 762 information, such as the frame's thread will be added. */ 763 frame->prologue_cache = sentinel_frame_cache (regcache); 764 /* For the moment there is only one sentinel frame implementation. */ 765 frame->unwind = sentinel_frame_unwind; 766 /* Link this frame back to itself. The frame is self referential 767 (the unwound PC is the same as the pc), so make it so. */ 768 frame->next = frame; 769 /* Make the sentinel frame's ID valid, but invalid. That way all 770 comparisons with it should fail. */ 771 frame->this_id.p = 1; 772 frame->this_id.value = null_frame_id; 773 if (frame_debug) 774 { 775 fprintf_unfiltered (gdb_stdlog, "{ create_sentinel_frame (...) -> "); 776 fprint_frame (gdb_stdlog, frame); 777 fprintf_unfiltered (gdb_stdlog, " }\n"); 778 } 779 return frame; 780} 781 782/* Info about the innermost stack frame (contents of FP register) */ 783 784static struct frame_info *current_frame; 785 786/* Cache for frame addresses already read by gdb. Valid only while 787 inferior is stopped. Control variables for the frame cache should 788 be local to this module. */ 789 790static struct obstack frame_cache_obstack; 791 792void * 793frame_obstack_zalloc (unsigned long size) 794{ 795 void *data = obstack_alloc (&frame_cache_obstack, size); 796 memset (data, 0, size); 797 return data; 798} 799 800CORE_ADDR * 801frame_saved_regs_zalloc (struct frame_info *fi) 802{ 803 fi->saved_regs = (CORE_ADDR *) 804 frame_obstack_zalloc (SIZEOF_FRAME_SAVED_REGS); 805 return fi->saved_regs; 806} 807 808CORE_ADDR * 809deprecated_get_frame_saved_regs (struct frame_info *fi) 810{ 811 return fi->saved_regs; 812} 813 814/* Return the innermost (currently executing) stack frame. This is 815 split into two functions. The function unwind_to_current_frame() 816 is wrapped in catch exceptions so that, even when the unwind of the 817 sentinel frame fails, the function still returns a stack frame. */ 818 819static int 820unwind_to_current_frame (struct ui_out *ui_out, void *args) 821{ 822 struct frame_info *frame = get_prev_frame (args); 823 /* A sentinel frame can fail to unwind, eg, because it's PC value 824 lands in somewhere like start. */ 825 if (frame == NULL) 826 return 1; 827 current_frame = frame; 828 return 0; 829} 830 831struct frame_info * 832get_current_frame (void) 833{ 834 /* First check, and report, the lack of registers. Having GDB 835 report "No stack!" or "No memory" when the target doesn't even 836 have registers is very confusing. Besides, "printcmd.exp" 837 explicitly checks that ``print $pc'' with no registers prints "No 838 registers". */ 839 if (!target_has_registers) 840 error ("No registers."); 841 if (!target_has_stack) 842 error ("No stack."); 843 if (!target_has_memory) 844 error ("No memory."); 845 if (current_frame == NULL) 846 { 847 struct frame_info *sentinel_frame = 848 create_sentinel_frame (current_regcache); 849 if (catch_exceptions (uiout, unwind_to_current_frame, sentinel_frame, 850 NULL, RETURN_MASK_ERROR) != 0) 851 { 852 /* Oops! Fake a current frame? Is this useful? It has a PC 853 of zero, for instance. */ 854 current_frame = sentinel_frame; 855 } 856 } 857 return current_frame; 858} 859 860/* The "selected" stack frame is used by default for local and arg 861 access. May be zero, for no selected frame. */ 862 863struct frame_info *deprecated_selected_frame; 864 865/* Return the selected frame. Always non-null (unless there isn't an 866 inferior sufficient for creating a frame) in which case an error is 867 thrown. */ 868 869struct frame_info * 870get_selected_frame (void) 871{ 872 if (deprecated_selected_frame == NULL) 873 /* Hey! Don't trust this. It should really be re-finding the 874 last selected frame of the currently selected thread. This, 875 though, is better than nothing. */ 876 select_frame (get_current_frame ()); 877 /* There is always a frame. */ 878 gdb_assert (deprecated_selected_frame != NULL); 879 return deprecated_selected_frame; 880} 881 882/* This is a variant of get_selected_frame which can be called when 883 the inferior does not have a frame; in that case it will return 884 NULL instead of calling error (). */ 885 886struct frame_info * 887deprecated_safe_get_selected_frame (void) 888{ 889 if (!target_has_registers || !target_has_stack || !target_has_memory) 890 return NULL; 891 return get_selected_frame (); 892} 893 894/* Select frame FI (or NULL - to invalidate the current frame). */ 895 896void 897select_frame (struct frame_info *fi) 898{ 899 struct symtab *s; 900 901 deprecated_selected_frame = fi; 902 /* NOTE: cagney/2002-05-04: FI can be NULL. This occures when the 903 frame is being invalidated. */ 904 if (selected_frame_level_changed_hook) 905 selected_frame_level_changed_hook (frame_relative_level (fi)); 906 907 /* FIXME: kseitz/2002-08-28: It would be nice to call 908 selected_frame_level_changed_event right here, but due to limitations 909 in the current interfaces, we would end up flooding UIs with events 910 because select_frame is used extensively internally. 911 912 Once we have frame-parameterized frame (and frame-related) commands, 913 the event notification can be moved here, since this function will only 914 be called when the users selected frame is being changed. */ 915 916 /* Ensure that symbols for this frame are read in. Also, determine the 917 source language of this frame, and switch to it if desired. */ 918 if (fi) 919 { 920 /* We retrieve the frame's symtab by using the frame PC. However 921 we cannot use the frame pc as is, because it usually points to 922 the instruction following the "call", which is sometimes the 923 first instruction of another function. So we rely on 924 get_frame_address_in_block() which provides us with a PC which 925 is guaranteed to be inside the frame's code block. */ 926 s = find_pc_symtab (get_frame_address_in_block (fi)); 927 if (s 928 && s->language != current_language->la_language 929 && s->language != language_unknown 930 && language_mode == language_mode_auto) 931 { 932 set_language (s->language); 933 } 934 } 935} 936 937/* Return the register saved in the simplistic ``saved_regs'' cache. 938 If the value isn't here AND a value is needed, try the next inner 939 most frame. */ 940 941static void 942legacy_saved_regs_prev_register (struct frame_info *next_frame, 943 void **this_prologue_cache, 944 int regnum, int *optimizedp, 945 enum lval_type *lvalp, CORE_ADDR *addrp, 946 int *realnump, void *bufferp) 947{ 948 /* HACK: New code is passed the next frame and this cache. 949 Unfortunately, old code expects this frame. Since this is a 950 backward compatibility hack, cheat by walking one level along the 951 prologue chain to the frame the old code expects. 952 953 Do not try this at home. Professional driver, closed course. */ 954 struct frame_info *frame = next_frame->prev; 955 gdb_assert (frame != NULL); 956 957 if (deprecated_get_frame_saved_regs (frame) == NULL) 958 { 959 /* If nothing's initialized the saved regs, do it now. */ 960 gdb_assert (DEPRECATED_FRAME_INIT_SAVED_REGS_P ()); 961 DEPRECATED_FRAME_INIT_SAVED_REGS (frame); 962 gdb_assert (deprecated_get_frame_saved_regs (frame) != NULL); 963 } 964 965 if (deprecated_get_frame_saved_regs (frame) != NULL 966 && deprecated_get_frame_saved_regs (frame)[regnum] != 0) 967 { 968 if (regnum == SP_REGNUM) 969 { 970 /* SP register treated specially. */ 971 *optimizedp = 0; 972 *lvalp = not_lval; 973 *addrp = 0; 974 *realnump = -1; 975 if (bufferp != NULL) 976 /* NOTE: cagney/2003-05-09: In-lined store_address with 977 it's body - store_unsigned_integer. */ 978 store_unsigned_integer (bufferp, DEPRECATED_REGISTER_RAW_SIZE (regnum), 979 deprecated_get_frame_saved_regs (frame)[regnum]); 980 } 981 else 982 { 983 /* Any other register is saved in memory, fetch it but cache 984 a local copy of its value. */ 985 *optimizedp = 0; 986 *lvalp = lval_memory; 987 *addrp = deprecated_get_frame_saved_regs (frame)[regnum]; 988 *realnump = -1; 989 if (bufferp != NULL) 990 { 991#if 1 992 /* Save each register value, as it is read in, in a 993 frame based cache. */ 994 void **regs = (*this_prologue_cache); 995 if (regs == NULL) 996 { 997 int sizeof_cache = ((NUM_REGS + NUM_PSEUDO_REGS) 998 * sizeof (void *)); 999 regs = frame_obstack_zalloc (sizeof_cache); 1000 (*this_prologue_cache) = regs; 1001 } 1002 if (regs[regnum] == NULL) 1003 { 1004 regs[regnum] 1005 = frame_obstack_zalloc (DEPRECATED_REGISTER_RAW_SIZE (regnum)); 1006 read_memory (deprecated_get_frame_saved_regs (frame)[regnum], regs[regnum], 1007 DEPRECATED_REGISTER_RAW_SIZE (regnum)); 1008 } 1009 memcpy (bufferp, regs[regnum], DEPRECATED_REGISTER_RAW_SIZE (regnum)); 1010#else 1011 /* Read the value in from memory. */ 1012 read_memory (deprecated_get_frame_saved_regs (frame)[regnum], bufferp, 1013 DEPRECATED_REGISTER_RAW_SIZE (regnum)); 1014#endif 1015 } 1016 } 1017 return; 1018 } 1019 1020 /* No luck. Assume this and the next frame have the same register 1021 value. Pass the unwind request down the frame chain to the next 1022 frame. Hopefully that frame will find the register's location. */ 1023 frame_register_unwind (next_frame, regnum, optimizedp, lvalp, addrp, 1024 realnump, bufferp); 1025} 1026 1027static void 1028legacy_saved_regs_this_id (struct frame_info *next_frame, 1029 void **this_prologue_cache, 1030 struct frame_id *id) 1031{ 1032 /* A developer is trying to bring up a new architecture, help them 1033 by providing a default unwinder that refuses to unwind anything 1034 (the ID is always NULL). In the case of legacy code, 1035 legacy_get_prev_frame() will have previously set ->this_id.p, so 1036 this code won't be called. */ 1037 (*id) = null_frame_id; 1038} 1039 1040const struct frame_unwind legacy_saved_regs_unwinder = { 1041 /* Not really. It gets overridden by legacy_get_prev_frame. */ 1042 UNKNOWN_FRAME, 1043 legacy_saved_regs_this_id, 1044 legacy_saved_regs_prev_register 1045}; 1046const struct frame_unwind *legacy_saved_regs_unwind = &legacy_saved_regs_unwinder; 1047 1048 1049/* Function: deprecated_generic_get_saved_register 1050 Find register number REGNUM relative to FRAME and put its (raw, 1051 target format) contents in *RAW_BUFFER. 1052 1053 Set *OPTIMIZED if the variable was optimized out (and thus can't be 1054 fetched). Note that this is never set to anything other than zero 1055 in this implementation. 1056 1057 Set *LVAL to lval_memory, lval_register, or not_lval, depending on 1058 whether the value was fetched from memory, from a register, or in a 1059 strange and non-modifiable way (e.g. a frame pointer which was 1060 calculated rather than fetched). We will use not_lval for values 1061 fetched from generic dummy frames. 1062 1063 Set *ADDRP to the address, either in memory or as a 1064 DEPRECATED_REGISTER_BYTE offset into the registers array. If the 1065 value is stored in a dummy frame, set *ADDRP to zero. 1066 1067 The argument RAW_BUFFER must point to aligned memory. */ 1068 1069void 1070deprecated_generic_get_saved_register (char *raw_buffer, int *optimized, 1071 CORE_ADDR *addrp, 1072 struct frame_info *frame, int regnum, 1073 enum lval_type *lval) 1074{ 1075 if (!target_has_registers) 1076 error ("No registers."); 1077 1078 /* Normal systems don't optimize out things with register numbers. */ 1079 if (optimized != NULL) 1080 *optimized = 0; 1081 1082 if (addrp) /* default assumption: not found in memory */ 1083 *addrp = 0; 1084 1085 /* Note: since the current frame's registers could only have been 1086 saved by frames INTERIOR TO the current frame, we skip examining 1087 the current frame itself: otherwise, we would be getting the 1088 previous frame's registers which were saved by the current frame. */ 1089 1090 if (frame != NULL) 1091 { 1092 for (frame = get_next_frame (frame); 1093 frame_relative_level (frame) >= 0; 1094 frame = get_next_frame (frame)) 1095 { 1096 if (get_frame_type (frame) == DUMMY_FRAME) 1097 { 1098 if (lval) /* found it in a CALL_DUMMY frame */ 1099 *lval = not_lval; 1100 if (raw_buffer) 1101 /* FIXME: cagney/2002-06-26: This should be via the 1102 gdbarch_register_read() method so that it, on the 1103 fly, constructs either a raw or pseudo register 1104 from the raw register cache. */ 1105 regcache_raw_read 1106 (deprecated_find_dummy_frame_regcache (get_frame_pc (frame), 1107 get_frame_base (frame)), 1108 regnum, raw_buffer); 1109 return; 1110 } 1111 1112 DEPRECATED_FRAME_INIT_SAVED_REGS (frame); 1113 if (deprecated_get_frame_saved_regs (frame) != NULL 1114 && deprecated_get_frame_saved_regs (frame)[regnum] != 0) 1115 { 1116 if (lval) /* found it saved on the stack */ 1117 *lval = lval_memory; 1118 if (regnum == SP_REGNUM) 1119 { 1120 if (raw_buffer) /* SP register treated specially */ 1121 /* NOTE: cagney/2003-05-09: In-line store_address 1122 with it's body - store_unsigned_integer. */ 1123 store_unsigned_integer (raw_buffer, 1124 DEPRECATED_REGISTER_RAW_SIZE (regnum), 1125 deprecated_get_frame_saved_regs (frame)[regnum]); 1126 } 1127 else 1128 { 1129 if (addrp) /* any other register */ 1130 *addrp = deprecated_get_frame_saved_regs (frame)[regnum]; 1131 if (raw_buffer) 1132 read_memory (deprecated_get_frame_saved_regs (frame)[regnum], raw_buffer, 1133 DEPRECATED_REGISTER_RAW_SIZE (regnum)); 1134 } 1135 return; 1136 } 1137 } 1138 } 1139 1140 /* If we get thru the loop to this point, it means the register was 1141 not saved in any frame. Return the actual live-register value. */ 1142 1143 if (lval) /* found it in a live register */ 1144 *lval = lval_register; 1145 if (addrp) 1146 *addrp = DEPRECATED_REGISTER_BYTE (regnum); 1147 if (raw_buffer) 1148 deprecated_read_register_gen (regnum, raw_buffer); 1149} 1150 1151/* Determine the frame's type based on its PC. */ 1152 1153static enum frame_type 1154frame_type_from_pc (CORE_ADDR pc) 1155{ 1156 /* FIXME: cagney/2002-11-24: Can't yet directly call 1157 pc_in_dummy_frame() as some architectures don't set 1158 PC_IN_CALL_DUMMY() to generic_pc_in_call_dummy() (remember the 1159 latter is implemented by simply calling pc_in_dummy_frame). */ 1160 if (DEPRECATED_USE_GENERIC_DUMMY_FRAMES 1161 && DEPRECATED_PC_IN_CALL_DUMMY (pc, 0, 0)) 1162 return DUMMY_FRAME; 1163 else 1164 { 1165 char *name; 1166 find_pc_partial_function (pc, &name, NULL, NULL); 1167 if (PC_IN_SIGTRAMP (pc, name)) 1168 return SIGTRAMP_FRAME; 1169 else 1170 return NORMAL_FRAME; 1171 } 1172} 1173 1174/* Create an arbitrary (i.e. address specified by user) or innermost frame. 1175 Always returns a non-NULL value. */ 1176 1177struct frame_info * 1178create_new_frame (CORE_ADDR addr, CORE_ADDR pc) 1179{ 1180 struct frame_info *fi; 1181 1182 if (frame_debug) 1183 { 1184 fprintf_unfiltered (gdb_stdlog, 1185 "{ create_new_frame (addr=0x%s, pc=0x%s) ", 1186 paddr_nz (addr), paddr_nz (pc)); 1187 } 1188 1189 fi = frame_obstack_zalloc (sizeof (struct frame_info)); 1190 1191 fi->next = create_sentinel_frame (current_regcache); 1192 1193 /* Select/initialize both the unwind function and the frame's type 1194 based on the PC. */ 1195 fi->unwind = frame_unwind_find_by_frame (fi->next); 1196 if (fi->unwind->type != UNKNOWN_FRAME) 1197 fi->type = fi->unwind->type; 1198 else 1199 fi->type = frame_type_from_pc (pc); 1200 1201 fi->this_id.p = 1; 1202 deprecated_update_frame_base_hack (fi, addr); 1203 deprecated_update_frame_pc_hack (fi, pc); 1204 1205 if (DEPRECATED_INIT_EXTRA_FRAME_INFO_P ()) 1206 DEPRECATED_INIT_EXTRA_FRAME_INFO (0, fi); 1207 1208 if (frame_debug) 1209 { 1210 fprintf_unfiltered (gdb_stdlog, "-> "); 1211 fprint_frame (gdb_stdlog, fi); 1212 fprintf_unfiltered (gdb_stdlog, " }\n"); 1213 } 1214 1215 return fi; 1216} 1217 1218/* Return the frame that THIS_FRAME calls (NULL if THIS_FRAME is the 1219 innermost frame). Be careful to not fall off the bottom of the 1220 frame chain and onto the sentinel frame. */ 1221 1222struct frame_info * 1223get_next_frame (struct frame_info *this_frame) 1224{ 1225 if (this_frame->level > 0) 1226 return this_frame->next; 1227 else 1228 return NULL; 1229} 1230 1231/* Flush the entire frame cache. */ 1232 1233void 1234flush_cached_frames (void) 1235{ 1236 /* Since we can't really be sure what the first object allocated was */ 1237 obstack_free (&frame_cache_obstack, 0); 1238 obstack_init (&frame_cache_obstack); 1239 1240 current_frame = NULL; /* Invalidate cache */ 1241 select_frame (NULL); 1242 annotate_frames_invalid (); 1243 if (frame_debug) 1244 fprintf_unfiltered (gdb_stdlog, "{ flush_cached_frames () }\n"); 1245} 1246 1247/* Flush the frame cache, and start a new one if necessary. */ 1248 1249void 1250reinit_frame_cache (void) 1251{ 1252 flush_cached_frames (); 1253 1254 /* FIXME: The inferior_ptid test is wrong if there is a corefile. */ 1255 if (PIDGET (inferior_ptid) != 0) 1256 { 1257 select_frame (get_current_frame ()); 1258 } 1259} 1260 1261/* Create the previous frame using the deprecated methods 1262 INIT_EXTRA_INFO, INIT_FRAME_PC and INIT_FRAME_PC_FIRST. */ 1263 1264static struct frame_info * 1265legacy_get_prev_frame (struct frame_info *this_frame) 1266{ 1267 CORE_ADDR address = 0; 1268 struct frame_info *prev; 1269 int fromleaf; 1270 1271 /* Don't frame_debug print legacy_get_prev_frame() here, just 1272 confuses the output. */ 1273 1274 /* Allocate the new frame. 1275 1276 There is no reason to worry about memory leaks, should the 1277 remainder of the function fail. The allocated memory will be 1278 quickly reclaimed when the frame cache is flushed, and the `we've 1279 been here before' check, in get_prev_frame will stop repeated 1280 memory allocation calls. */ 1281 prev = FRAME_OBSTACK_ZALLOC (struct frame_info); 1282 prev->level = this_frame->level + 1; 1283 1284 /* Do not completely wire it in to the frame chain. Some (bad) code 1285 in INIT_FRAME_EXTRA_INFO tries to look along frame->prev to pull 1286 some fancy tricks (of course such code is, by definition, 1287 recursive). 1288 1289 On the other hand, methods, such as get_frame_pc() and 1290 get_frame_base() rely on being able to walk along the frame 1291 chain. Make certain that at least they work by providing that 1292 link. Of course things manipulating prev can't go back. */ 1293 prev->next = this_frame; 1294 1295 /* NOTE: cagney/2002-11-18: Should have been correctly setting the 1296 frame's type here, before anything else, and not last, at the 1297 bottom of this function. The various 1298 DEPRECATED_INIT_EXTRA_FRAME_INFO, DEPRECATED_INIT_FRAME_PC, 1299 DEPRECATED_INIT_FRAME_PC_FIRST and 1300 DEPRECATED_FRAME_INIT_SAVED_REGS methods are full of work-arounds 1301 that handle the frame not being correctly set from the start. 1302 Unfortunately those same work-arounds rely on the type defaulting 1303 to NORMAL_FRAME. Ulgh! The new frame code does not have this 1304 problem. */ 1305 prev->type = UNKNOWN_FRAME; 1306 1307 /* A legacy frame's ID is always computed here. Mark it as valid. */ 1308 prev->this_id.p = 1; 1309 1310 /* Handle sentinel frame unwind as a special case. */ 1311 if (this_frame->level < 0) 1312 { 1313 /* Try to unwind the PC. If that doesn't work, assume we've reached 1314 the oldest frame and simply return. Is there a better sentinal 1315 value? The unwound PC value is then used to initialize the new 1316 previous frame's type. 1317 1318 Note that the pc-unwind is intentionally performed before the 1319 frame chain. This is ok since, for old targets, both 1320 frame_pc_unwind (nee, DEPRECATED_FRAME_SAVED_PC) and 1321 DEPRECATED_FRAME_CHAIN()) assume THIS_FRAME's data structures 1322 have already been initialized (using 1323 DEPRECATED_INIT_EXTRA_FRAME_INFO) and hence the call order 1324 doesn't matter. 1325 1326 By unwinding the PC first, it becomes possible to, in the case of 1327 a dummy frame, avoid also unwinding the frame ID. This is 1328 because (well ignoring the PPC) a dummy frame can be located 1329 using THIS_FRAME's frame ID. */ 1330 1331 deprecated_update_frame_pc_hack (prev, frame_pc_unwind (this_frame)); 1332 if (get_frame_pc (prev) == 0) 1333 { 1334 /* The allocated PREV_FRAME will be reclaimed when the frame 1335 obstack is next purged. */ 1336 if (frame_debug) 1337 { 1338 fprintf_unfiltered (gdb_stdlog, "-> "); 1339 fprint_frame (gdb_stdlog, NULL); 1340 fprintf_unfiltered (gdb_stdlog, 1341 " // unwound legacy PC zero }\n"); 1342 } 1343 return NULL; 1344 } 1345 1346 /* Set the unwind functions based on that identified PC. Ditto 1347 for the "type" but strongly prefer the unwinder's frame type. */ 1348 prev->unwind = frame_unwind_find_by_frame (prev->next); 1349 if (prev->unwind->type == UNKNOWN_FRAME) 1350 prev->type = frame_type_from_pc (get_frame_pc (prev)); 1351 else 1352 prev->type = prev->unwind->type; 1353 1354 /* Find the prev's frame's ID. */ 1355 if (prev->type == DUMMY_FRAME 1356 && gdbarch_unwind_dummy_id_p (current_gdbarch)) 1357 { 1358 /* When unwinding a normal frame, the stack structure is 1359 determined by analyzing the frame's function's code (be 1360 it using brute force prologue analysis, or the dwarf2 1361 CFI). In the case of a dummy frame, that simply isn't 1362 possible. The The PC is either the program entry point, 1363 or some random address on the stack. Trying to use that 1364 PC to apply standard frame ID unwind techniques is just 1365 asking for trouble. */ 1366 /* Use an architecture specific method to extract the prev's 1367 dummy ID from the next frame. Note that this method uses 1368 frame_register_unwind to obtain the register values 1369 needed to determine the dummy frame's ID. */ 1370 prev->this_id.value = gdbarch_unwind_dummy_id (current_gdbarch, 1371 this_frame); 1372 } 1373 else 1374 { 1375 /* We're unwinding a sentinel frame, the PC of which is 1376 pointing at a stack dummy. Fake up the dummy frame's ID 1377 using the same sequence as is found a traditional 1378 unwinder. Once all architectures supply the 1379 unwind_dummy_id method, this code can go away. */ 1380 prev->this_id.value = frame_id_build (deprecated_read_fp (), 1381 read_pc ()); 1382 } 1383 1384 /* Check that the unwound ID is valid. */ 1385 if (!frame_id_p (prev->this_id.value)) 1386 { 1387 if (frame_debug) 1388 { 1389 fprintf_unfiltered (gdb_stdlog, "-> "); 1390 fprint_frame (gdb_stdlog, NULL); 1391 fprintf_unfiltered (gdb_stdlog, 1392 " // unwound legacy ID invalid }\n"); 1393 } 1394 return NULL; 1395 } 1396 1397 /* Check that the new frame isn't inner to (younger, below, 1398 next) the old frame. If that happens the frame unwind is 1399 going backwards. */ 1400 /* FIXME: cagney/2003-02-25: Ignore the sentinel frame since 1401 that doesn't have a valid frame ID. Should instead set the 1402 sentinel frame's frame ID to a `sentinel'. Leave it until 1403 after the switch to storing the frame ID, instead of the 1404 frame base, in the frame object. */ 1405 1406 /* Link it in. */ 1407 this_frame->prev = prev; 1408 1409 /* FIXME: cagney/2002-01-19: This call will go away. Instead of 1410 initializing extra info, all frames will use the frame_cache 1411 (passed to the unwind functions) to store additional frame 1412 info. Unfortunately legacy targets can't use 1413 legacy_get_prev_frame() to unwind the sentinel frame and, 1414 consequently, are forced to take this code path and rely on 1415 the below call to DEPRECATED_INIT_EXTRA_FRAME_INFO to 1416 initialize the inner-most frame. */ 1417 if (DEPRECATED_INIT_EXTRA_FRAME_INFO_P ()) 1418 { 1419 DEPRECATED_INIT_EXTRA_FRAME_INFO (0, prev); 1420 } 1421 1422 if (prev->type == NORMAL_FRAME) 1423 prev->this_id.value.code_addr 1424 = get_pc_function_start (prev->this_id.value.code_addr); 1425 1426 if (frame_debug) 1427 { 1428 fprintf_unfiltered (gdb_stdlog, "-> "); 1429 fprint_frame (gdb_stdlog, prev); 1430 fprintf_unfiltered (gdb_stdlog, " } // legacy innermost frame\n"); 1431 } 1432 return prev; 1433 } 1434 1435 /* This code only works on normal frames. A sentinel frame, where 1436 the level is -1, should never reach this code. */ 1437 gdb_assert (this_frame->level >= 0); 1438 1439 /* On some machines it is possible to call a function without 1440 setting up a stack frame for it. On these machines, we 1441 define this macro to take two args; a frameinfo pointer 1442 identifying a frame and a variable to set or clear if it is 1443 or isn't leafless. */ 1444 1445 /* Still don't want to worry about this except on the innermost 1446 frame. This macro will set FROMLEAF if THIS_FRAME is a frameless 1447 function invocation. */ 1448 if (this_frame->level == 0) 1449 /* FIXME: 2002-11-09: Frameless functions can occure anywhere in 1450 the frame chain, not just the inner most frame! The generic, 1451 per-architecture, frame code should handle this and the below 1452 should simply be removed. */ 1453 fromleaf = (DEPRECATED_FRAMELESS_FUNCTION_INVOCATION_P () 1454 && DEPRECATED_FRAMELESS_FUNCTION_INVOCATION (this_frame)); 1455 else 1456 fromleaf = 0; 1457 1458 if (fromleaf) 1459 /* A frameless inner-most frame. The `FP' (which isn't an 1460 architecture frame-pointer register!) of the caller is the same 1461 as the callee. */ 1462 /* FIXME: 2002-11-09: There isn't any reason to special case this 1463 edge condition. Instead the per-architecture code should hande 1464 it locally. */ 1465 /* FIXME: cagney/2003-06-16: This returns the inner most stack 1466 address for the previous frame, that, however, is wrong. It 1467 should be the inner most stack address for the previous to 1468 previous frame. This is because it is the previous to previous 1469 frame's innermost stack address that is constant through out 1470 the lifetime of the previous frame (trust me :-). */ 1471 address = get_frame_base (this_frame); 1472 else 1473 { 1474 /* Two macros defined in tm.h specify the machine-dependent 1475 actions to be performed here. 1476 1477 First, get the frame's chain-pointer. 1478 1479 If that is zero, the frame is the outermost frame or a leaf 1480 called by the outermost frame. This means that if start 1481 calls main without a frame, we'll return 0 (which is fine 1482 anyway). 1483 1484 Nope; there's a problem. This also returns when the current 1485 routine is a leaf of main. This is unacceptable. We move 1486 this to after the ffi test; I'd rather have backtraces from 1487 start go curfluy than have an abort called from main not show 1488 main. */ 1489 if (DEPRECATED_FRAME_CHAIN_P ()) 1490 address = DEPRECATED_FRAME_CHAIN (this_frame); 1491 else 1492 { 1493 /* Someone is part way through coverting an old architecture 1494 to the new frame code. Implement FRAME_CHAIN the way the 1495 new frame will. */ 1496 /* Find PREV frame's unwinder. */ 1497 prev->unwind = frame_unwind_find_by_frame (this_frame->next); 1498 /* FIXME: cagney/2003-04-02: Rather than storing the frame's 1499 type in the frame, the unwinder's type should be returned 1500 directly. Unfortunately, legacy code, called by 1501 legacy_get_prev_frame, explicitly set the frames type 1502 using the method deprecated_set_frame_type(). */ 1503 prev->type = prev->unwind->type; 1504 /* Find PREV frame's ID. */ 1505 prev->unwind->this_id (this_frame, 1506 &prev->prologue_cache, 1507 &prev->this_id.value); 1508 prev->this_id.p = 1; 1509 address = prev->this_id.value.stack_addr; 1510 } 1511 1512 if (!legacy_frame_chain_valid (address, this_frame)) 1513 { 1514 if (frame_debug) 1515 { 1516 fprintf_unfiltered (gdb_stdlog, "-> "); 1517 fprint_frame (gdb_stdlog, NULL); 1518 fprintf_unfiltered (gdb_stdlog, 1519 " // legacy frame chain invalid }\n"); 1520 } 1521 return NULL; 1522 } 1523 } 1524 if (address == 0) 1525 { 1526 if (frame_debug) 1527 { 1528 fprintf_unfiltered (gdb_stdlog, "-> "); 1529 fprint_frame (gdb_stdlog, NULL); 1530 fprintf_unfiltered (gdb_stdlog, 1531 " // legacy frame chain NULL }\n"); 1532 } 1533 return NULL; 1534 } 1535 1536 /* Link in the already allocated prev frame. */ 1537 this_frame->prev = prev; 1538 deprecated_update_frame_base_hack (prev, address); 1539 1540 /* This change should not be needed, FIXME! We should determine 1541 whether any targets *need* DEPRECATED_INIT_FRAME_PC to happen 1542 after DEPRECATED_INIT_EXTRA_FRAME_INFO and come up with a simple 1543 way to express what goes on here. 1544 1545 DEPRECATED_INIT_EXTRA_FRAME_INFO is called from two places: 1546 create_new_frame (where the PC is already set up) and here (where 1547 it isn't). DEPRECATED_INIT_FRAME_PC is only called from here, 1548 always after DEPRECATED_INIT_EXTRA_FRAME_INFO. 1549 1550 The catch is the MIPS, where DEPRECATED_INIT_EXTRA_FRAME_INFO 1551 requires the PC value (which hasn't been set yet). Some other 1552 machines appear to require DEPRECATED_INIT_EXTRA_FRAME_INFO 1553 before they can do DEPRECATED_INIT_FRAME_PC. Phoo. 1554 1555 We shouldn't need DEPRECATED_INIT_FRAME_PC_FIRST to add more 1556 complication to an already overcomplicated part of GDB. 1557 gnu@cygnus.com, 15Sep92. 1558 1559 Assuming that some machines need DEPRECATED_INIT_FRAME_PC after 1560 DEPRECATED_INIT_EXTRA_FRAME_INFO, one possible scheme: 1561 1562 SETUP_INNERMOST_FRAME(): Default version is just create_new_frame 1563 (deprecated_read_fp ()), read_pc ()). Machines with extra frame 1564 info would do that (or the local equivalent) and then set the 1565 extra fields. 1566 1567 SETUP_ARBITRARY_FRAME(argc, argv): Only change here is that 1568 create_new_frame would no longer init extra frame info; 1569 SETUP_ARBITRARY_FRAME would have to do that. 1570 1571 INIT_PREV_FRAME(fromleaf, prev) Replace 1572 DEPRECATED_INIT_EXTRA_FRAME_INFO and DEPRECATED_INIT_FRAME_PC. 1573 This should also return a flag saying whether to keep the new 1574 frame, or whether to discard it, because on some machines (e.g. 1575 mips) it is really awkward to have DEPRECATED_FRAME_CHAIN_VALID 1576 called BEFORE DEPRECATED_INIT_EXTRA_FRAME_INFO (there is no good 1577 way to get information deduced in DEPRECATED_FRAME_CHAIN_VALID 1578 into the extra fields of the new frame). std_frame_pc(fromleaf, 1579 prev) 1580 1581 This is the default setting for INIT_PREV_FRAME. It just does 1582 what the default DEPRECATED_INIT_FRAME_PC does. Some machines 1583 will call it from INIT_PREV_FRAME (either at the beginning, the 1584 end, or in the middle). Some machines won't use it. 1585 1586 kingdon@cygnus.com, 13Apr93, 31Jan94, 14Dec94. */ 1587 1588 /* NOTE: cagney/2002-11-09: Just ignore the above! There is no 1589 reason for things to be this complicated. 1590 1591 The trick is to assume that there is always a frame. Instead of 1592 special casing the inner-most frame, create fake frame 1593 (containing the hardware registers) that is inner to the 1594 user-visible inner-most frame (...) and then unwind from that. 1595 That way architecture code can use use the standard 1596 frame_XX_unwind() functions and not differentiate between the 1597 inner most and any other case. 1598 1599 Since there is always a frame to unwind from, there is always 1600 somewhere (THIS_FRAME) to store all the info needed to construct 1601 a new (previous) frame without having to first create it. This 1602 means that the convolution below - needing to carefully order a 1603 frame's initialization - isn't needed. 1604 1605 The irony here though, is that DEPRECATED_FRAME_CHAIN(), at least 1606 for a more up-to-date architecture, always calls 1607 FRAME_SAVED_PC(), and FRAME_SAVED_PC() computes the PC but 1608 without first needing the frame! Instead of the convolution 1609 below, we could have simply called FRAME_SAVED_PC() and been done 1610 with it! Note that FRAME_SAVED_PC() is being superseed by 1611 frame_pc_unwind() and that function does have somewhere to cache 1612 that PC value. */ 1613 1614 if (DEPRECATED_INIT_FRAME_PC_FIRST_P ()) 1615 deprecated_update_frame_pc_hack (prev, 1616 DEPRECATED_INIT_FRAME_PC_FIRST (fromleaf, 1617 prev)); 1618 1619 if (DEPRECATED_INIT_EXTRA_FRAME_INFO_P ()) 1620 DEPRECATED_INIT_EXTRA_FRAME_INFO (fromleaf, prev); 1621 1622 /* This entry is in the frame queue now, which is good since 1623 FRAME_SAVED_PC may use that queue to figure out its value (see 1624 tm-sparc.h). We want the pc saved in the inferior frame. */ 1625 if (DEPRECATED_INIT_FRAME_PC_P ()) 1626 deprecated_update_frame_pc_hack (prev, 1627 DEPRECATED_INIT_FRAME_PC (fromleaf, 1628 prev)); 1629 1630 /* If ->frame and ->pc are unchanged, we are in the process of 1631 getting ourselves into an infinite backtrace. Some architectures 1632 check this in DEPRECATED_FRAME_CHAIN or thereabouts, but it seems 1633 like there is no reason this can't be an architecture-independent 1634 check. */ 1635 if (get_frame_base (prev) == get_frame_base (this_frame) 1636 && get_frame_pc (prev) == get_frame_pc (this_frame)) 1637 { 1638 this_frame->prev = NULL; 1639 obstack_free (&frame_cache_obstack, prev); 1640 if (frame_debug) 1641 { 1642 fprintf_unfiltered (gdb_stdlog, "-> "); 1643 fprint_frame (gdb_stdlog, NULL); 1644 fprintf_unfiltered (gdb_stdlog, 1645 " // legacy this.id == prev.id }\n"); 1646 } 1647 return NULL; 1648 } 1649 1650 /* Initialize the code used to unwind the frame PREV based on the PC 1651 (and probably other architectural information). The PC lets you 1652 check things like the debug info at that point (dwarf2cfi?) and 1653 use that to decide how the frame should be unwound. 1654 1655 If there isn't a FRAME_CHAIN, the code above will have already 1656 done this. */ 1657 if (prev->unwind == NULL) 1658 prev->unwind = frame_unwind_find_by_frame (prev->next); 1659 1660 /* If the unwinder provides a frame type, use it. Otherwize 1661 continue on to that heuristic mess. */ 1662 if (prev->unwind->type != UNKNOWN_FRAME) 1663 { 1664 prev->type = prev->unwind->type; 1665 if (prev->type == NORMAL_FRAME) 1666 /* FIXME: cagney/2003-06-16: would get_frame_pc() be better? */ 1667 prev->this_id.value.code_addr 1668 = get_pc_function_start (prev->this_id.value.code_addr); 1669 if (frame_debug) 1670 { 1671 fprintf_unfiltered (gdb_stdlog, "-> "); 1672 fprint_frame (gdb_stdlog, prev); 1673 fprintf_unfiltered (gdb_stdlog, " } // legacy with unwound type\n"); 1674 } 1675 return prev; 1676 } 1677 1678 /* NOTE: cagney/2002-11-18: The code segments, found in 1679 create_new_frame and get_prev_frame(), that initializes the 1680 frames type is subtly different. The latter only updates ->type 1681 when it encounters a SIGTRAMP_FRAME or DUMMY_FRAME. This stops 1682 get_prev_frame() overriding the frame's type when the INIT code 1683 has previously set it. This is really somewhat bogus. The 1684 initialization, as seen in create_new_frame(), should occur 1685 before the INIT function has been called. */ 1686 if (DEPRECATED_USE_GENERIC_DUMMY_FRAMES 1687 && (DEPRECATED_PC_IN_CALL_DUMMY_P () 1688 ? DEPRECATED_PC_IN_CALL_DUMMY (get_frame_pc (prev), 0, 0) 1689 : pc_in_dummy_frame (get_frame_pc (prev)))) 1690 prev->type = DUMMY_FRAME; 1691 else 1692 { 1693 /* FIXME: cagney/2002-11-10: This should be moved to before the 1694 INIT code above so that the INIT code knows what the frame's 1695 type is (in fact, for a [generic] dummy-frame, the type can 1696 be set and then the entire initialization can be skipped. 1697 Unforunatly, its the INIT code that sets the PC (Hmm, catch 1698 22). */ 1699 char *name; 1700 find_pc_partial_function (get_frame_pc (prev), &name, NULL, NULL); 1701 if (PC_IN_SIGTRAMP (get_frame_pc (prev), name)) 1702 prev->type = SIGTRAMP_FRAME; 1703 /* FIXME: cagney/2002-11-11: Leave prev->type alone. Some 1704 architectures are forcing the frame's type in INIT so we 1705 don't want to override it here. Remember, NORMAL_FRAME == 0, 1706 so it all works (just :-/). Once this initialization is 1707 moved to the start of this function, all this nastness will 1708 go away. */ 1709 } 1710 1711 if (prev->type == NORMAL_FRAME) 1712 prev->this_id.value.code_addr 1713 = get_pc_function_start (prev->this_id.value.code_addr); 1714 1715 if (frame_debug) 1716 { 1717 fprintf_unfiltered (gdb_stdlog, "-> "); 1718 fprint_frame (gdb_stdlog, prev); 1719 fprintf_unfiltered (gdb_stdlog, " } // legacy with confused type\n"); 1720 } 1721 1722 return prev; 1723} 1724 1725/* Return a structure containing various interesting information 1726 about the frame that called THIS_FRAME. Returns NULL 1727 if there is no such frame. 1728 1729 This function tests some target-independent conditions that should 1730 terminate the frame chain, such as unwinding past main(). It 1731 should not contain any target-dependent tests, such as checking 1732 whether the program-counter is zero. */ 1733 1734struct frame_info * 1735get_prev_frame (struct frame_info *this_frame) 1736{ 1737 struct frame_info *prev_frame; 1738 1739 if (frame_debug) 1740 { 1741 fprintf_unfiltered (gdb_stdlog, "{ get_prev_frame (this_frame="); 1742 if (this_frame != NULL) 1743 fprintf_unfiltered (gdb_stdlog, "%d", this_frame->level); 1744 else 1745 fprintf_unfiltered (gdb_stdlog, "<NULL>"); 1746 fprintf_unfiltered (gdb_stdlog, ") "); 1747 } 1748 1749 /* Return the inner-most frame, when the caller passes in NULL. */ 1750 /* NOTE: cagney/2002-11-09: Not sure how this would happen. The 1751 caller should have previously obtained a valid frame using 1752 get_selected_frame() and then called this code - only possibility 1753 I can think of is code behaving badly. 1754 1755 NOTE: cagney/2003-01-10: Talk about code behaving badly. Check 1756 block_innermost_frame(). It does the sequence: frame = NULL; 1757 while (1) { frame = get_prev_frame (frame); .... }. Ulgh! Why 1758 it couldn't be written better, I don't know. 1759 1760 NOTE: cagney/2003-01-11: I suspect what is happening is 1761 block_innermost_frame() is, when the target has no state 1762 (registers, memory, ...), still calling this function. The 1763 assumption being that this function will return NULL indicating 1764 that a frame isn't possible, rather than checking that the target 1765 has state and then calling get_current_frame() and 1766 get_prev_frame(). This is a guess mind. */ 1767 if (this_frame == NULL) 1768 { 1769 /* NOTE: cagney/2002-11-09: There was a code segment here that 1770 would error out when CURRENT_FRAME was NULL. The comment 1771 that went with it made the claim ... 1772 1773 ``This screws value_of_variable, which just wants a nice 1774 clean NULL return from block_innermost_frame if there are no 1775 frames. I don't think I've ever seen this message happen 1776 otherwise. And returning NULL here is a perfectly legitimate 1777 thing to do.'' 1778 1779 Per the above, this code shouldn't even be called with a NULL 1780 THIS_FRAME. */ 1781 return current_frame; 1782 } 1783 1784 /* There is always a frame. If this assertion fails, suspect that 1785 something should be calling get_selected_frame() or 1786 get_current_frame(). */ 1787 gdb_assert (this_frame != NULL); 1788 1789 /* Make sure we pass an address within THIS_FRAME's code block to 1790 inside_main_func. Otherwise, we might stop unwinding at a 1791 function which has a call instruction as its last instruction if 1792 that function immediately precedes main(). */ 1793 if (this_frame->level >= 0 1794 && !backtrace_past_main 1795 && inside_main_func (get_frame_address_in_block (this_frame))) 1796 /* Don't unwind past main(), bug always unwind the sentinel frame. 1797 Note, this is done _before_ the frame has been marked as 1798 previously unwound. That way if the user later decides to 1799 allow unwinds past main(), that just happens. */ 1800 { 1801 if (frame_debug) 1802 fprintf_unfiltered (gdb_stdlog, "-> NULL // inside main func }\n"); 1803 return NULL; 1804 } 1805 1806 if (this_frame->level > backtrace_limit) 1807 { 1808 error ("Backtrace limit of %d exceeded", backtrace_limit); 1809 } 1810 1811 /* If we're already inside the entry function for the main objfile, 1812 then it isn't valid. Don't apply this test to a dummy frame - 1813 dummy frame PC's typically land in the entry func. Don't apply 1814 this test to the sentinel frame. Sentinel frames should always 1815 be allowed to unwind. */ 1816 /* NOTE: cagney/2003-02-25: Don't enable until someone has found 1817 hard evidence that this is needed. */ 1818 /* NOTE: cagney/2003-07-07: Fixed a bug in inside_main_func - wasn't 1819 checking for "main" in the minimal symbols. With that fixed 1820 asm-source tests now stop in "main" instead of halting the 1821 backtrace in wierd and wonderful ways somewhere inside the entry 1822 file. Suspect that deprecated_inside_entry_file and 1823 inside_entry_func tests were added to work around that (now 1824 fixed) case. */ 1825 /* NOTE: cagney/2003-07-15: danielj (if I'm reading it right) 1826 suggested having the inside_entry_func test use the 1827 inside_main_func msymbol trick (along with entry_point_address I 1828 guess) to determine the address range of the start function. 1829 That should provide a far better stopper than the current 1830 heuristics. */ 1831 /* NOTE: cagney/2003-07-15: Need to add a "set backtrace 1832 beyond-entry-func" command so that this can be selectively 1833 disabled. */ 1834 if (0 1835#if 0 1836 && backtrace_beyond_entry_func 1837#endif 1838 && this_frame->type != DUMMY_FRAME && this_frame->level >= 0 1839 && inside_entry_func (this_frame)) 1840 { 1841 if (frame_debug) 1842 { 1843 fprintf_unfiltered (gdb_stdlog, "-> "); 1844 fprint_frame (gdb_stdlog, NULL); 1845 fprintf_unfiltered (gdb_stdlog, "// inside entry func }\n"); 1846 } 1847 return NULL; 1848 } 1849 1850 /* Assume that the only way to get a zero PC is through something 1851 like a SIGSEGV or a dummy frame, and hence that NORMAL frames 1852 will never unwind a zero PC. */ 1853 if (this_frame->level > 0 1854 && get_frame_type (this_frame) == NORMAL_FRAME 1855 && get_frame_type (get_next_frame (this_frame)) == NORMAL_FRAME 1856 && get_frame_pc (this_frame) == 0) 1857 { 1858 if (frame_debug) 1859 { 1860 fprintf_unfiltered (gdb_stdlog, "-> "); 1861 fprint_frame (gdb_stdlog, this_frame->prev); 1862 fprintf_unfiltered (gdb_stdlog, " // zero PC \n"); 1863 } 1864 return NULL; 1865 } 1866 1867 /* Only try to do the unwind once. */ 1868 if (this_frame->prev_p) 1869 { 1870 if (frame_debug) 1871 { 1872 fprintf_unfiltered (gdb_stdlog, "-> "); 1873 fprint_frame (gdb_stdlog, this_frame->prev); 1874 fprintf_unfiltered (gdb_stdlog, " // cached \n"); 1875 } 1876 return this_frame->prev; 1877 } 1878 this_frame->prev_p = 1; 1879 1880 /* If we're inside the entry file, it isn't valid. Don't apply this 1881 test to a dummy frame - dummy frame PC's typically land in the 1882 entry file. Don't apply this test to the sentinel frame. 1883 Sentinel frames should always be allowed to unwind. */ 1884 /* NOTE: drow/2002-12-25: should there be a way to disable this 1885 check? It assumes a single small entry file, and the way some 1886 debug readers (e.g. dbxread) figure out which object is the 1887 entry file is somewhat hokey. */ 1888 /* NOTE: cagney/2003-01-10: If there is a way of disabling this test 1889 then it should probably be moved to before the ->prev_p test, 1890 above. */ 1891 /* NOTE: vinschen/2003-04-01: Disabled. It turns out that the call 1892 to deprecated_inside_entry_file destroys a meaningful backtrace 1893 under some conditions. E. g. the backtrace tests in the 1894 asm-source testcase are broken for some targets. In this test 1895 the functions are all implemented as part of one file and the 1896 testcase is not necessarily linked with a start file (depending 1897 on the target). What happens is, that the first frame is printed 1898 normaly and following frames are treated as being inside the 1899 enttry file then. This way, only the #0 frame is printed in the 1900 backtrace output. */ 1901 if (0 1902 && this_frame->type != DUMMY_FRAME && this_frame->level >= 0 1903 && deprecated_inside_entry_file (get_frame_pc (this_frame))) 1904 { 1905 if (frame_debug) 1906 { 1907 fprintf_unfiltered (gdb_stdlog, "-> "); 1908 fprint_frame (gdb_stdlog, NULL); 1909 fprintf_unfiltered (gdb_stdlog, " // inside entry file }\n"); 1910 } 1911 return NULL; 1912 } 1913 1914 /* If any of the old frame initialization methods are around, use 1915 the legacy get_prev_frame method. */ 1916 if (legacy_frame_p (current_gdbarch)) 1917 { 1918 prev_frame = legacy_get_prev_frame (this_frame); 1919 return prev_frame; 1920 } 1921 1922 /* Check that this frame's ID was valid. If it wasn't, don't try to 1923 unwind to the prev frame. Be careful to not apply this test to 1924 the sentinel frame. */ 1925 if (this_frame->level >= 0 && !frame_id_p (get_frame_id (this_frame))) 1926 { 1927 if (frame_debug) 1928 { 1929 fprintf_unfiltered (gdb_stdlog, "-> "); 1930 fprint_frame (gdb_stdlog, NULL); 1931 fprintf_unfiltered (gdb_stdlog, " // this ID is NULL }\n"); 1932 } 1933 return NULL; 1934 } 1935 1936 /* Check that this frame's ID isn't inner to (younger, below, next) 1937 the next frame. This happens when a frame unwind goes backwards. 1938 Since the sentinel frame doesn't really exist, don't compare the 1939 inner-most against that sentinel. */ 1940 if (this_frame->level > 0 1941 && frame_id_inner (get_frame_id (this_frame), 1942 get_frame_id (this_frame->next))) 1943 error ("Previous frame inner to this frame (corrupt stack?)"); 1944 1945 /* Check that this and the next frame are not identical. If they 1946 are, there is most likely a stack cycle. As with the inner-than 1947 test above, avoid comparing the inner-most and sentinel frames. */ 1948 if (this_frame->level > 0 1949 && frame_id_eq (get_frame_id (this_frame), 1950 get_frame_id (this_frame->next))) 1951 error ("Previous frame identical to this frame (corrupt stack?)"); 1952 1953 /* Allocate the new frame but do not wire it in to the frame chain. 1954 Some (bad) code in INIT_FRAME_EXTRA_INFO tries to look along 1955 frame->next to pull some fancy tricks (of course such code is, by 1956 definition, recursive). Try to prevent it. 1957 1958 There is no reason to worry about memory leaks, should the 1959 remainder of the function fail. The allocated memory will be 1960 quickly reclaimed when the frame cache is flushed, and the `we've 1961 been here before' check above will stop repeated memory 1962 allocation calls. */ 1963 prev_frame = FRAME_OBSTACK_ZALLOC (struct frame_info); 1964 prev_frame->level = this_frame->level + 1; 1965 1966 /* Don't yet compute ->unwind (and hence ->type). It is computed 1967 on-demand in get_frame_type, frame_register_unwind, and 1968 get_frame_id. */ 1969 1970 /* Don't yet compute the frame's ID. It is computed on-demand by 1971 get_frame_id(). */ 1972 1973 /* The unwound frame ID is validate at the start of this function, 1974 as part of the logic to decide if that frame should be further 1975 unwound, and not here while the prev frame is being created. 1976 Doing this makes it possible for the user to examine a frame that 1977 has an invalid frame ID. 1978 1979 Some very old VAX code noted: [...] For the sake of argument, 1980 suppose that the stack is somewhat trashed (which is one reason 1981 that "info frame" exists). So, return 0 (indicating we don't 1982 know the address of the arglist) if we don't know what frame this 1983 frame calls. */ 1984 1985 /* Link it in. */ 1986 this_frame->prev = prev_frame; 1987 prev_frame->next = this_frame; 1988 1989 if (frame_debug) 1990 { 1991 fprintf_unfiltered (gdb_stdlog, "-> "); 1992 fprint_frame (gdb_stdlog, prev_frame); 1993 fprintf_unfiltered (gdb_stdlog, " }\n"); 1994 } 1995 1996 return prev_frame; 1997} 1998 1999CORE_ADDR 2000get_frame_pc (struct frame_info *frame) 2001{ 2002 gdb_assert (frame->next != NULL); 2003 return frame_pc_unwind (frame->next); 2004} 2005 2006/* Return an address of that falls within the frame's code block. */ 2007 2008CORE_ADDR 2009frame_unwind_address_in_block (struct frame_info *next_frame) 2010{ 2011 /* A draft address. */ 2012 CORE_ADDR pc = frame_pc_unwind (next_frame); 2013 2014 if ((frame_tdep_pc_fixup != NULL) && (frame_tdep_pc_fixup(&pc) == 0)) 2015 return pc; 2016 2017 /* If THIS frame is not inner most (i.e., NEXT isn't the sentinel), 2018 and NEXT is `normal' (i.e., not a sigtramp, dummy, ....) THIS 2019 frame's PC ends up pointing at the instruction fallowing the 2020 "call". Adjust that PC value so that it falls on the call 2021 instruction (which, hopefully, falls within THIS frame's code 2022 block. So far it's proved to be a very good approximation. See 2023 get_frame_type for why ->type can't be used. */ 2024 if (next_frame->level >= 0 2025 && get_frame_type (next_frame) == NORMAL_FRAME) 2026 --pc; 2027 return pc; 2028} 2029 2030CORE_ADDR 2031get_frame_address_in_block (struct frame_info *this_frame) 2032{ 2033 return frame_unwind_address_in_block (this_frame->next); 2034} 2035 2036static int 2037pc_notcurrent (struct frame_info *frame) 2038{ 2039 /* If FRAME is not the innermost frame, that normally means that 2040 FRAME->pc points at the return instruction (which is *after* the 2041 call instruction), and we want to get the line containing the 2042 call (because the call is where the user thinks the program is). 2043 However, if the next frame is either a SIGTRAMP_FRAME or a 2044 DUMMY_FRAME, then the next frame will contain a saved interrupt 2045 PC and such a PC indicates the current (rather than next) 2046 instruction/line, consequently, for such cases, want to get the 2047 line containing fi->pc. */ 2048 struct frame_info *next = get_next_frame (frame); 2049 int notcurrent = (next != NULL && get_frame_type (next) == NORMAL_FRAME); 2050 return notcurrent; 2051} 2052 2053void 2054find_frame_sal (struct frame_info *frame, struct symtab_and_line *sal) 2055{ 2056 (*sal) = find_pc_line (get_frame_pc (frame), pc_notcurrent (frame)); 2057} 2058 2059/* Per "frame.h", return the ``address'' of the frame. Code should 2060 really be using get_frame_id(). */ 2061CORE_ADDR 2062get_frame_base (struct frame_info *fi) 2063{ 2064 return get_frame_id (fi).stack_addr; 2065} 2066 2067/* High-level offsets into the frame. Used by the debug info. */ 2068 2069CORE_ADDR 2070get_frame_base_address (struct frame_info *fi) 2071{ 2072 if (get_frame_type (fi) != NORMAL_FRAME) 2073 return 0; 2074 if (fi->base == NULL) 2075 fi->base = frame_base_find_by_frame (fi->next); 2076 /* Sneaky: If the low-level unwind and high-level base code share a 2077 common unwinder, let them share the prologue cache. */ 2078 if (fi->base->unwind == fi->unwind) 2079 return fi->base->this_base (fi->next, &fi->prologue_cache); 2080 return fi->base->this_base (fi->next, &fi->base_cache); 2081} 2082 2083CORE_ADDR 2084get_frame_locals_address (struct frame_info *fi) 2085{ 2086 void **cache; 2087 if (get_frame_type (fi) != NORMAL_FRAME) 2088 return 0; 2089 /* If there isn't a frame address method, find it. */ 2090 if (fi->base == NULL) 2091 fi->base = frame_base_find_by_frame (fi->next); 2092 /* Sneaky: If the low-level unwind and high-level base code share a 2093 common unwinder, let them share the prologue cache. */ 2094 if (fi->base->unwind == fi->unwind) 2095 cache = &fi->prologue_cache; 2096 else 2097 cache = &fi->base_cache; 2098 return fi->base->this_locals (fi->next, cache); 2099} 2100 2101CORE_ADDR 2102get_frame_args_address (struct frame_info *fi) 2103{ 2104 void **cache; 2105 if (get_frame_type (fi) != NORMAL_FRAME) 2106 return 0; 2107 /* If there isn't a frame address method, find it. */ 2108 if (fi->base == NULL) 2109 fi->base = frame_base_find_by_frame (fi->next); 2110 /* Sneaky: If the low-level unwind and high-level base code share a 2111 common unwinder, let them share the prologue cache. */ 2112 if (fi->base->unwind == fi->unwind) 2113 cache = &fi->prologue_cache; 2114 else 2115 cache = &fi->base_cache; 2116 return fi->base->this_args (fi->next, cache); 2117} 2118 2119/* Level of the selected frame: 0 for innermost, 1 for its caller, ... 2120 or -1 for a NULL frame. */ 2121 2122int 2123frame_relative_level (struct frame_info *fi) 2124{ 2125 if (fi == NULL) 2126 return -1; 2127 else 2128 return fi->level; 2129} 2130 2131enum frame_type 2132get_frame_type (struct frame_info *frame) 2133{ 2134 /* Some targets still don't use [generic] dummy frames. Catch them 2135 here. */ 2136 if (!DEPRECATED_USE_GENERIC_DUMMY_FRAMES 2137 && deprecated_frame_in_dummy (frame)) 2138 return DUMMY_FRAME; 2139 2140 /* Some legacy code, e.g, mips_init_extra_frame_info() wants 2141 to determine the frame's type prior to it being completely 2142 initialized. Don't attempt to lazily initialize ->unwind for 2143 legacy code. It will be initialized in legacy_get_prev_frame(). */ 2144 if (frame->unwind == NULL && !legacy_frame_p (current_gdbarch)) 2145 { 2146 /* Initialize the frame's unwinder because it is that which 2147 provides the frame's type. */ 2148 frame->unwind = frame_unwind_find_by_frame (frame->next); 2149 /* FIXME: cagney/2003-04-02: Rather than storing the frame's 2150 type in the frame, the unwinder's type should be returned 2151 directly. Unfortunately, legacy code, called by 2152 legacy_get_prev_frame, explicitly set the frames type using 2153 the method deprecated_set_frame_type(). */ 2154 frame->type = frame->unwind->type; 2155 } 2156 if (frame->type == UNKNOWN_FRAME) 2157 return NORMAL_FRAME; 2158 else 2159 return frame->type; 2160} 2161 2162void 2163deprecated_set_frame_type (struct frame_info *frame, enum frame_type type) 2164{ 2165 /* Arrrg! See comment in "frame.h". */ 2166 frame->type = type; 2167} 2168 2169struct frame_extra_info * 2170get_frame_extra_info (struct frame_info *fi) 2171{ 2172 return fi->extra_info; 2173} 2174 2175struct frame_extra_info * 2176frame_extra_info_zalloc (struct frame_info *fi, long size) 2177{ 2178 fi->extra_info = frame_obstack_zalloc (size); 2179 return fi->extra_info; 2180} 2181 2182void 2183deprecated_update_frame_pc_hack (struct frame_info *frame, CORE_ADDR pc) 2184{ 2185 if (frame_debug) 2186 fprintf_unfiltered (gdb_stdlog, 2187 "{ deprecated_update_frame_pc_hack (frame=%d,pc=0x%s) }\n", 2188 frame->level, paddr_nz (pc)); 2189 /* NOTE: cagney/2003-03-11: Some architectures (e.g., Arm) are 2190 maintaining a locally allocated frame object. Since such frame's 2191 are not in the frame chain, it isn't possible to assume that the 2192 frame has a next. Sigh. */ 2193 if (frame->next != NULL) 2194 { 2195 /* While we're at it, update this frame's cached PC value, found 2196 in the next frame. Oh for the day when "struct frame_info" 2197 is opaque and this hack on hack can just go away. */ 2198 frame->next->prev_pc.value = pc; 2199 frame->next->prev_pc.p = 1; 2200 } 2201} 2202 2203void 2204deprecated_update_frame_base_hack (struct frame_info *frame, CORE_ADDR base) 2205{ 2206 if (frame_debug) 2207 fprintf_unfiltered (gdb_stdlog, 2208 "{ deprecated_update_frame_base_hack (frame=%d,base=0x%s) }\n", 2209 frame->level, paddr_nz (base)); 2210 /* See comment in "frame.h". */ 2211 frame->this_id.value.stack_addr = base; 2212} 2213 2214struct frame_info * 2215deprecated_frame_xmalloc_with_cleanup (long sizeof_saved_regs, 2216 long sizeof_extra_info) 2217{ 2218 struct frame_info *frame = XMALLOC (struct frame_info); 2219 memset (frame, 0, sizeof (*frame)); 2220 frame->this_id.p = 1; 2221 make_cleanup (xfree, frame); 2222 if (sizeof_saved_regs > 0) 2223 { 2224 frame->saved_regs = xcalloc (1, sizeof_saved_regs); 2225 make_cleanup (xfree, frame->saved_regs); 2226 } 2227 if (sizeof_extra_info > 0) 2228 { 2229 frame->extra_info = xcalloc (1, sizeof_extra_info); 2230 make_cleanup (xfree, frame->extra_info); 2231 } 2232 return frame; 2233} 2234 2235/* Memory access methods. */ 2236 2237void 2238get_frame_memory (struct frame_info *this_frame, CORE_ADDR addr, void *buf, 2239 int len) 2240{ 2241 read_memory (addr, buf, len); 2242} 2243 2244LONGEST 2245get_frame_memory_signed (struct frame_info *this_frame, CORE_ADDR addr, 2246 int len) 2247{ 2248 return read_memory_integer (addr, len); 2249} 2250 2251ULONGEST 2252get_frame_memory_unsigned (struct frame_info *this_frame, CORE_ADDR addr, 2253 int len) 2254{ 2255 return read_memory_unsigned_integer (addr, len); 2256} 2257 2258/* Architecture method. */ 2259 2260struct gdbarch * 2261get_frame_arch (struct frame_info *this_frame) 2262{ 2263 return current_gdbarch; 2264} 2265 2266/* Stack pointer methods. */ 2267 2268CORE_ADDR 2269get_frame_sp (struct frame_info *this_frame) 2270{ 2271 return frame_sp_unwind (this_frame->next); 2272} 2273 2274CORE_ADDR 2275frame_sp_unwind (struct frame_info *next_frame) 2276{ 2277 /* Normality, an architecture that provides a way of obtaining any 2278 frame inner-most address. */ 2279 if (gdbarch_unwind_sp_p (current_gdbarch)) 2280 return gdbarch_unwind_sp (current_gdbarch, next_frame); 2281 /* Things are looking grim. If it's the inner-most frame and there 2282 is a TARGET_READ_SP then that can be used. */ 2283 if (next_frame->level < 0 && TARGET_READ_SP_P ()) 2284 return TARGET_READ_SP (); 2285 /* Now things are really are grim. Hope that the value returned by 2286 the SP_REGNUM register is meaningful. */ 2287 if (SP_REGNUM >= 0) 2288 { 2289 ULONGEST sp; 2290 frame_unwind_unsigned_register (next_frame, SP_REGNUM, &sp); 2291 return sp; 2292 } 2293 internal_error (__FILE__, __LINE__, "Missing unwind SP method"); 2294} 2295 2296 2297int 2298legacy_frame_p (struct gdbarch *current_gdbarch) 2299{ 2300 if (DEPRECATED_INIT_FRAME_PC_P () 2301 || DEPRECATED_INIT_FRAME_PC_FIRST_P () 2302 || DEPRECATED_INIT_EXTRA_FRAME_INFO_P () 2303 || DEPRECATED_FRAME_CHAIN_P ()) 2304 /* No question, it's a legacy frame. */ 2305 return 1; 2306 if (gdbarch_unwind_dummy_id_p (current_gdbarch)) 2307 /* No question, it's not a legacy frame (provided none of the 2308 deprecated methods checked above are present that is). */ 2309 return 0; 2310 if (DEPRECATED_TARGET_READ_FP_P () 2311 || DEPRECATED_FP_REGNUM >= 0) 2312 /* Assume it's legacy. If you're trying to convert a legacy frame 2313 target to the new mechanism, get rid of these. legacy 2314 get_prev_frame requires these when unwind_frame_id isn't 2315 available. */ 2316 return 1; 2317 /* Default to assuming that it's brand new code, and hence not 2318 legacy. Force it down the non-legacy path so that the new code 2319 uses the new frame mechanism from day one. Dummy frame's won't 2320 work very well but we can live with that. */ 2321 return 0; 2322} 2323 2324extern initialize_file_ftype _initialize_frame; /* -Wmissing-prototypes */ 2325 2326static struct cmd_list_element *set_backtrace_cmdlist; 2327static struct cmd_list_element *show_backtrace_cmdlist; 2328 2329static void 2330set_backtrace_cmd (char *args, int from_tty) 2331{ 2332 help_list (set_backtrace_cmdlist, "set backtrace ", -1, gdb_stdout); 2333} 2334 2335static void 2336show_backtrace_cmd (char *args, int from_tty) 2337{ 2338 cmd_show_list (show_backtrace_cmdlist, from_tty, ""); 2339} 2340 2341void 2342_initialize_frame (void) 2343{ 2344 obstack_init (&frame_cache_obstack); 2345 2346 add_prefix_cmd ("backtrace", class_maintenance, set_backtrace_cmd, "\ 2347Set backtrace specific variables.\n\ 2348Configure backtrace variables such as the backtrace limit", 2349 &set_backtrace_cmdlist, "set backtrace ", 2350 0/*allow-unknown*/, &setlist); 2351 add_prefix_cmd ("backtrace", class_maintenance, show_backtrace_cmd, "\ 2352Show backtrace specific variables\n\ 2353Show backtrace variables such as the backtrace limit", 2354 &show_backtrace_cmdlist, "show backtrace ", 2355 0/*allow-unknown*/, &showlist); 2356 2357 add_setshow_boolean_cmd ("past-main", class_obscure, 2358 &backtrace_past_main, "\ 2359Set whether backtraces should continue past \"main\".\n\ 2360Normally the caller of \"main\" is not of interest, so GDB will terminate\n\ 2361the backtrace at \"main\". Set this variable if you need to see the rest\n\ 2362of the stack trace.", "\ 2363Show whether backtraces should continue past \"main\".\n\ 2364Normally the caller of \"main\" is not of interest, so GDB will terminate\n\ 2365the backtrace at \"main\". Set this variable if you need to see the rest\n\ 2366of the stack trace.", 2367 NULL, NULL, &set_backtrace_cmdlist, 2368 &show_backtrace_cmdlist); 2369 2370 add_setshow_uinteger_cmd ("limit", class_obscure, 2371 &backtrace_limit, "\ 2372Set an upper bound on the number of backtrace levels.\n\ 2373No more than the specified number of frames can be displayed or examined.\n\ 2374Zero is unlimited.", "\ 2375Show the upper bound on the number of backtrace levels.", 2376 NULL, NULL, &set_backtrace_cmdlist, 2377 &show_backtrace_cmdlist); 2378 2379 /* Debug this files internals. */ 2380 add_show_from_set (add_set_cmd ("frame", class_maintenance, var_zinteger, 2381 &frame_debug, "Set frame debugging.\n\ 2382When non-zero, frame specific internal debugging is enabled.", &setdebuglist), 2383 &showdebuglist); 2384} 2385