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