gdb/block.c

   1 /* Block-related functions for the GNU debugger, GDB.
   2
   3    Copyright (C) 2003, 2007-2012 Free Software Foundation, Inc.
   4
   5    This file is part of GDB.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  19
  20 #include "defs.h"
  21 #include "block.h"
  22 #include "symtab.h"
  23 #include "symfile.h"
  24 #include "gdb_obstack.h"
  25 #include "cp-support.h"
  26 #include "addrmap.h"
  27 #include "gdbtypes.h"
  28 #include "exceptions.h"
  29
  30 /* This is used by struct block to store namespace-related info for
  31    C++ files, namely using declarations and the current namespace in
  32    scope.  */
  33
  34 struct block_namespace_info
  35 {
  36   const char *scope;
  37   struct using_direct *using;
  38 };
  39
  40 static void block_initialize_namespace (struct block *block,
  41                                         struct obstack *obstack);
  42
  43 /* Return Nonzero if block a is lexically nested within block b,
  44    or if a and b have the same pc range.
  45    Return zero otherwise.  */
  46
  47 int
  48 contained_in (const struct block *a, const struct block *b)
  49 {
  50   if (!a || !b)
  51     return 0;
  52
  53   do
  54     {
  55       if (a == b)
  56         return 1;
  57       /* If A is a function block, then A cannot be contained in B,
  58          except if A was inlined.  */
  59       if (BLOCK_FUNCTION (a) != NULL && !block_inlined_p (a))
  60         return 0;
  61       a = BLOCK_SUPERBLOCK (a);
  62     }
  63   while (a != NULL);
  64
  65   return 0;
  66 }
  67
  68
  69 /* Return the symbol for the function which contains a specified
  70    lexical block, described by a struct block BL.  The return value
  71    will not be an inlined function; the containing function will be
  72    returned instead.  */
  73
  74 struct symbol *
  75 block_linkage_function (const struct block *bl)
  76 {
  77   while ((BLOCK_FUNCTION (bl) == NULL || block_inlined_p (bl))
  78          && BLOCK_SUPERBLOCK (bl) != NULL)
  79     bl = BLOCK_SUPERBLOCK (bl);
  80
  81   return BLOCK_FUNCTION (bl);
  82 }
  83
  84 /* Return the symbol for the function which contains a specified
  85    block, described by a struct block BL.  The return value will be
  86    the closest enclosing function, which might be an inline
  87    function.  */
  88
  89 struct symbol *
  90 block_containing_function (const struct block *bl)
  91 {
  92   while (BLOCK_FUNCTION (bl) == NULL && BLOCK_SUPERBLOCK (bl) != NULL)
  93     bl = BLOCK_SUPERBLOCK (bl);
  94
  95   return BLOCK_FUNCTION (bl);
  96 }
  97
  98 /* Return one if BL represents an inlined function.  */
  99
 100 int
 101 block_inlined_p (const struct block *bl)
 102 {
 103   return BLOCK_FUNCTION (bl) != NULL && SYMBOL_INLINED (BLOCK_FUNCTION (bl));
 104 }
 105
 106 /* A helper function that checks whether PC is in the blockvector BL.
 107    It returns the containing block if there is one, or else NULL.  */
 108
 109 static struct block *
 110 find_block_in_blockvector (struct blockvector *bl, CORE_ADDR pc)
 111 {
 112   struct block *b;
 113   int bot, top, half;
 114
 115   /* If we have an addrmap mapping code addresses to blocks, then use
 116      that.  */
 117   if (BLOCKVECTOR_MAP (bl))
 118     return addrmap_find (BLOCKVECTOR_MAP (bl), pc);
 119
 120   /* Otherwise, use binary search to find the last block that starts
 121      before PC.
 122      Note: GLOBAL_BLOCK is block 0, STATIC_BLOCK is block 1.
 123      They both have the same START,END values.
 124      Historically this code would choose STATIC_BLOCK over GLOBAL_BLOCK but the
 125      fact that this choice was made was subtle, now we make it explicit.  */
 126   gdb_assert (BLOCKVECTOR_NBLOCKS (bl) >= 2);
 127   bot = STATIC_BLOCK;
 128   top = BLOCKVECTOR_NBLOCKS (bl);
 129
 130   while (top - bot > 1)
 131     {
 132       half = (top - bot + 1) >> 1;
 133       b = BLOCKVECTOR_BLOCK (bl, bot + half);
 134       if (BLOCK_START (b) <= pc)
 135         bot += half;
 136       else
 137         top = bot + half;
 138     }
 139
 140   /* Now search backward for a block that ends after PC.  */
 141
 142   while (bot >= STATIC_BLOCK)
 143     {
 144       b = BLOCKVECTOR_BLOCK (bl, bot);
 145       if (BLOCK_END (b) > pc)
 146         return b;
 147       bot--;
 148     }
 149
 150   return NULL;
 151 }
 152
 153 /* Return the blockvector immediately containing the innermost lexical
 154    block containing the specified pc value and section, or 0 if there
 155    is none.  PBLOCK is a pointer to the block.  If PBLOCK is NULL, we
 156    don't pass this information back to the caller.  */
 157
 158 struct blockvector *
 159 blockvector_for_pc_sect (CORE_ADDR pc, struct obj_section *section,
 160                          struct block **pblock, struct symtab *symtab)
 161 {
 162   struct blockvector *bl;
 163   struct block *b;
 164
 165   if (symtab == 0)              /* if no symtab specified by caller */
 166     {
 167       /* First search all symtabs for one whose file contains our pc */
 168       symtab = find_pc_sect_symtab (pc, section);
 169       if (symtab == 0)
 170         return 0;
 171     }
 172
 173   bl = BLOCKVECTOR (symtab);
 174
 175   /* Then search that symtab for the smallest block that wins.  */
 176   b = find_block_in_blockvector (bl, pc);
 177   if (b == NULL)
 178     return NULL;
 179
 180   if (pblock)
 181     *pblock = b;
 182   return bl;
 183 }
 184
 185 /* Return true if the blockvector BV contains PC, false otherwise.  */
 186
 187 int
 188 blockvector_contains_pc (struct blockvector *bv, CORE_ADDR pc)
 189 {
 190   return find_block_in_blockvector (bv, pc) != NULL;
 191 }
 192
 193 /* Return call_site for specified PC in GDBARCH.  PC must match exactly, it
 194    must be the next instruction after call (or after tail call jump).  Throw
 195    NO_ENTRY_VALUE_ERROR otherwise.  This function never returns NULL.  */
 196
 197 struct call_site *
 198 call_site_for_pc (struct gdbarch *gdbarch, CORE_ADDR pc)
 199 {
 200   struct symtab *symtab;
 201   void **slot = NULL;
 202
 203   /* -1 as tail call PC can be already after the compilation unit range.  */
 204   symtab = find_pc_symtab (pc - 1);
 205
 206   if (symtab != NULL && symtab->call_site_htab != NULL)
 207     slot = htab_find_slot (symtab->call_site_htab, &pc, NO_INSERT);
 208
 209   if (slot == NULL)
 210     {
 211       struct minimal_symbol *msym = lookup_minimal_symbol_by_pc (pc);
 212
 213       /* DW_TAG_gnu_call_site will be missing just if GCC could not determine
 214          the call target.  */
 215       throw_error (NO_ENTRY_VALUE_ERROR,
 216                    _("DW_OP_GNU_entry_value resolving cannot find "
 217                      "DW_TAG_GNU_call_site %s in %s"),
 218                    paddress (gdbarch, pc),
 219                    msym == NULL ? "???" : SYMBOL_PRINT_NAME (msym));
 220     }
 221
 222   return *slot;
 223 }
 224
 225 /* Return the blockvector immediately containing the innermost lexical block
 226    containing the specified pc value, or 0 if there is none.
 227    Backward compatibility, no section.  */
 228
 229 struct blockvector *
 230 blockvector_for_pc (CORE_ADDR pc, struct block **pblock)
 231 {
 232   return blockvector_for_pc_sect (pc, find_pc_mapped_section (pc),
 233                                   pblock, NULL);
 234 }
 235
 236 /* Return the innermost lexical block containing the specified pc value
 237    in the specified section, or 0 if there is none.  */
 238
 239 struct block *
 240 block_for_pc_sect (CORE_ADDR pc, struct obj_section *section)
 241 {
 242   struct blockvector *bl;
 243   struct block *b;
 244
 245   bl = blockvector_for_pc_sect (pc, section, &b, NULL);
 246   if (bl)
 247     return b;
 248   return 0;
 249 }
 250
 251 /* Return the innermost lexical block containing the specified pc value,
 252    or 0 if there is none.  Backward compatibility, no section.  */
 253
 254 struct block *
 255 block_for_pc (CORE_ADDR pc)
 256 {
 257   return block_for_pc_sect (pc, find_pc_mapped_section (pc));
 258 }
 259
 260 /* Now come some functions designed to deal with C++ namespace issues.
 261    The accessors are safe to use even in the non-C++ case.  */
 262
 263 /* This returns the namespace that BLOCK is enclosed in, or "" if it
 264    isn't enclosed in a namespace at all.  This travels the chain of
 265    superblocks looking for a scope, if necessary.  */
 266
 267 const char *
 268 block_scope (const struct block *block)
 269 {
 270   for (; block != NULL; block = BLOCK_SUPERBLOCK (block))
 271     {
 272       if (BLOCK_NAMESPACE (block) != NULL
 273           && BLOCK_NAMESPACE (block)->scope != NULL)
 274         return BLOCK_NAMESPACE (block)->scope;
 275     }
 276
 277   return "";
 278 }
 279
 280 /* Set BLOCK's scope member to SCOPE; if needed, allocate memory via
 281    OBSTACK.  (It won't make a copy of SCOPE, however, so that already
 282    has to be allocated correctly.)  */
 283
 284 void
 285 block_set_scope (struct block *block, const char *scope,
 286                  struct obstack *obstack)
 287 {
 288   block_initialize_namespace (block, obstack);
 289
 290   BLOCK_NAMESPACE (block)->scope = scope;
 291 }
 292
 293 /* This returns the using directives list associated with BLOCK, if
 294    any.  */
 295
 296 struct using_direct *
 297 block_using (const struct block *block)
 298 {
 299   if (block == NULL || BLOCK_NAMESPACE (block) == NULL)
 300     return NULL;
 301   else
 302     return BLOCK_NAMESPACE (block)->using;
 303 }
 304
 305 /* Set BLOCK's using member to USING; if needed, allocate memory via
 306    OBSTACK.  (It won't make a copy of USING, however, so that already
 307    has to be allocated correctly.)  */
 308
 309 void
 310 block_set_using (struct block *block,
 311                  struct using_direct *using,
 312                  struct obstack *obstack)
 313 {
 314   block_initialize_namespace (block, obstack);
 315
 316   BLOCK_NAMESPACE (block)->using = using;
 317 }
 318
 319 /* If BLOCK_NAMESPACE (block) is NULL, allocate it via OBSTACK and
 320    ititialize its members to zero.  */
 321
 322 static void
 323 block_initialize_namespace (struct block *block, struct obstack *obstack)
 324 {
 325   if (BLOCK_NAMESPACE (block) == NULL)
 326     {
 327       BLOCK_NAMESPACE (block)
 328         = obstack_alloc (obstack, sizeof (struct block_namespace_info));
 329       BLOCK_NAMESPACE (block)->scope = NULL;
 330       BLOCK_NAMESPACE (block)->using = NULL;
 331     }
 332 }
 333
 334 /* Return the static block associated to BLOCK.  Return NULL if block
 335    is NULL or if block is a global block.  */
 336
 337 const struct block *
 338 block_static_block (const struct block *block)
 339 {
 340   if (block == NULL || BLOCK_SUPERBLOCK (block) == NULL)
 341     return NULL;
 342
 343   while (BLOCK_SUPERBLOCK (BLOCK_SUPERBLOCK (block)) != NULL)
 344     block = BLOCK_SUPERBLOCK (block);
 345
 346   return block;
 347 }
 348
 349 /* Return the static block associated to BLOCK.  Return NULL if block
 350    is NULL.  */
 351
 352 const struct block *
 353 block_global_block (const struct block *block)
 354 {
 355   if (block == NULL)
 356     return NULL;
 357
 358   while (BLOCK_SUPERBLOCK (block) != NULL)
 359     block = BLOCK_SUPERBLOCK (block);
 360
 361   return block;
 362 }
 363
 364 /* Allocate a block on OBSTACK, and initialize its elements to
 365    zero/NULL.  This is useful for creating "dummy" blocks that don't
 366    correspond to actual source files.
 367
 368    Warning: it sets the block's BLOCK_DICT to NULL, which isn't a
 369    valid value.  If you really don't want the block to have a
 370    dictionary, then you should subsequently set its BLOCK_DICT to
 371    dict_create_linear (obstack, NULL).  */
 372
 373 struct block *
 374 allocate_block (struct obstack *obstack)
 375 {
 376   struct block *bl = obstack_alloc (obstack, sizeof (struct block));
 377
 378   BLOCK_START (bl) = 0;
 379   BLOCK_END (bl) = 0;
 380   BLOCK_FUNCTION (bl) = NULL;
 381   BLOCK_SUPERBLOCK (bl) = NULL;
 382   BLOCK_DICT (bl) = NULL;
 383   BLOCK_NAMESPACE (bl) = NULL;
 384
 385   return bl;
 386 }
 387
 388 /* Allocate a global block.  */
 389
 390 struct block *
 391 allocate_global_block (struct obstack *obstack)
 392 {
 393   struct global_block *bl = OBSTACK_ZALLOC (obstack, struct global_block);
 394
 395   return &bl->block;
 396 }
 397
 398 /* Set the symtab of the global block.  */
 399
 400 void
 401 set_block_symtab (struct block *block, struct symtab *symtab)
 402 {
 403   struct global_block *gb;
 404
 405   gdb_assert (BLOCK_SUPERBLOCK (block) == NULL);
 406   gb = (struct global_block *) block;
 407   gdb_assert (gb->symtab == NULL);
 408   gb->symtab = symtab;
 409 }
 410
 411 /* Return the symtab of the global block.  */
 412
 413 static struct symtab *
 414 get_block_symtab (const struct block *block)
 415 {
 416   struct global_block *gb;
 417
 418   gdb_assert (BLOCK_SUPERBLOCK (block) == NULL);
 419   gb = (struct global_block *) block;
 420   gdb_assert (gb->symtab != NULL);
 421   return gb->symtab;
 422 }
 423
 424 \f
 425
 426 /* Initialize a block iterator, either to iterate over a single block,
 427    or, for static and global blocks, all the included symtabs as
 428    well.  */
 429
 430 static void
 431 initialize_block_iterator (const struct block *block,
 432                            struct block_iterator *iter)
 433 {
 434   enum block_enum which;
 435   struct symtab *symtab;
 436
 437   iter->idx = -1;
 438
 439   if (BLOCK_SUPERBLOCK (block) == NULL)
 440     {
 441       which = GLOBAL_BLOCK;
 442       symtab = get_block_symtab (block);
 443     }
 444   else if (BLOCK_SUPERBLOCK (BLOCK_SUPERBLOCK (block)) == NULL)
 445     {
 446       which = STATIC_BLOCK;
 447       symtab = get_block_symtab (BLOCK_SUPERBLOCK (block));
 448     }
 449   else
 450     {
 451       iter->d.block = block;
 452       /* A signal value meaning that we're iterating over a single
 453          block.  */
 454       iter->which = FIRST_LOCAL_BLOCK;
 455       return;
 456     }
 457
 458   /* If this is an included symtab, find the canonical includer and
 459      use it instead.  */
 460   while (symtab->user != NULL)
 461     symtab = symtab->user;
 462
 463   /* Putting this check here simplifies the logic of the iterator
 464      functions.  If there are no included symtabs, we only need to
 465      search a single block, so we might as well just do that
 466      directly.  */
 467   if (symtab->includes == NULL)
 468     {
 469       iter->d.block = block;
 470       /* A signal value meaning that we're iterating over a single
 471          block.  */
 472       iter->which = FIRST_LOCAL_BLOCK;
 473     }
 474   else
 475     {
 476       iter->d.symtab = symtab;
 477       iter->which = which;
 478     }
 479 }
 480
 481 /* A helper function that finds the current symtab over whose static
 482    or global block we should iterate.  */
 483
 484 static struct symtab *
 485 find_iterator_symtab (struct block_iterator *iterator)
 486 {
 487   if (iterator->idx == -1)
 488     return iterator->d.symtab;
 489   return iterator->d.symtab->includes[iterator->idx];
 490 }
 491
 492 /* Perform a single step for a plain block iterator, iterating across
 493    symbol tables as needed.  Returns the next symbol, or NULL when
 494    iteration is complete.  */
 495
 496 static struct symbol *
 497 block_iterator_step (struct block_iterator *iterator, int first)
 498 {
 499   struct symbol *sym;
 500
 501   gdb_assert (iterator->which != FIRST_LOCAL_BLOCK);
 502
 503   while (1)
 504     {
 505       if (first)
 506         {
 507           struct symtab *symtab = find_iterator_symtab (iterator);
 508           const struct block *block;
 509
 510           /* Iteration is complete.  */
 511           if (symtab == NULL)
 512             return  NULL;
 513
 514           block = BLOCKVECTOR_BLOCK (BLOCKVECTOR (symtab), iterator->which);
 515           sym = dict_iterator_first (BLOCK_DICT (block), &iterator->dict_iter);
 516         }
 517       else
 518         sym = dict_iterator_next (&iterator->dict_iter);
 519
 520       if (sym != NULL)
 521         return sym;
 522
 523       /* We have finished iterating the appropriate block of one
 524          symtab.  Now advance to the next symtab and begin iteration
 525          there.  */
 526       ++iterator->idx;
 527       first = 1;
 528     }
 529 }
 530
 531 /* See block.h.  */
 532
 533 struct symbol *
 534 block_iterator_first (const struct block *block,
 535                       struct block_iterator *iterator)
 536 {
 537   initialize_block_iterator (block, iterator);
 538
 539   if (iterator->which == FIRST_LOCAL_BLOCK)
 540     return dict_iterator_first (block->dict, &iterator->dict_iter);
 541
 542   return block_iterator_step (iterator, 1);
 543 }
 544
 545 /* See block.h.  */
 546
 547 struct symbol *
 548 block_iterator_next (struct block_iterator *iterator)
 549 {
 550   if (iterator->which == FIRST_LOCAL_BLOCK)
 551     return dict_iterator_next (&iterator->dict_iter);
 552
 553   return block_iterator_step (iterator, 0);
 554 }
 555
 556 /* Perform a single step for a "name" block iterator, iterating across
 557    symbol tables as needed.  Returns the next symbol, or NULL when
 558    iteration is complete.  */
 559
 560 static struct symbol *
 561 block_iter_name_step (struct block_iterator *iterator, const char *name,
 562                       int first)
 563 {
 564   struct symbol *sym;
 565
 566   gdb_assert (iterator->which != FIRST_LOCAL_BLOCK);
 567
 568   while (1)
 569     {
 570       if (first)
 571         {
 572           struct symtab *symtab = find_iterator_symtab (iterator);
 573           const struct block *block;
 574
 575           /* Iteration is complete.  */
 576           if (symtab == NULL)
 577             return  NULL;
 578
 579           block = BLOCKVECTOR_BLOCK (BLOCKVECTOR (symtab), iterator->which);
 580           sym = dict_iter_name_first (BLOCK_DICT (block), name,
 581                                       &iterator->dict_iter);
 582         }
 583       else
 584         sym = dict_iter_name_next (name, &iterator->dict_iter);
 585
 586       if (sym != NULL)
 587         return sym;
 588
 589       /* We have finished iterating the appropriate block of one
 590          symtab.  Now advance to the next symtab and begin iteration
 591          there.  */
 592       ++iterator->idx;
 593       first = 1;
 594     }
 595 }
 596
 597 /* See block.h.  */
 598
 599 struct symbol *
 600 block_iter_name_first (const struct block *block,
 601                        const char *name,
 602                        struct block_iterator *iterator)
 603 {
 604   initialize_block_iterator (block, iterator);
 605
 606   if (iterator->which == FIRST_LOCAL_BLOCK)
 607     return dict_iter_name_first (block->dict, name, &iterator->dict_iter);
 608
 609   return block_iter_name_step (iterator, name, 1);
 610 }
 611
 612 /* See block.h.  */
 613
 614 struct symbol *
 615 block_iter_name_next (const char *name, struct block_iterator *iterator)
 616 {
 617   if (iterator->which == FIRST_LOCAL_BLOCK)
 618     return dict_iter_name_next (name, &iterator->dict_iter);
 619
 620   return block_iter_name_step (iterator, name, 0);
 621 }
 622
 623 /* Perform a single step for a "match" block iterator, iterating
 624    across symbol tables as needed.  Returns the next symbol, or NULL
 625    when iteration is complete.  */
 626
 627 static struct symbol *
 628 block_iter_match_step (struct block_iterator *iterator,
 629                        const char *name,
 630                        symbol_compare_ftype *compare,
 631                        int first)
 632 {
 633   struct symbol *sym;
 634
 635   gdb_assert (iterator->which != FIRST_LOCAL_BLOCK);
 636
 637   while (1)
 638     {
 639       if (first)
 640         {
 641           struct symtab *symtab = find_iterator_symtab (iterator);
 642           const struct block *block;
 643
 644           /* Iteration is complete.  */
 645           if (symtab == NULL)
 646             return  NULL;
 647
 648           block = BLOCKVECTOR_BLOCK (BLOCKVECTOR (symtab), iterator->which);
 649           sym = dict_iter_match_first (BLOCK_DICT (block), name,
 650                                        compare, &iterator->dict_iter);
 651         }
 652       else
 653         sym = dict_iter_match_next (name, compare, &iterator->dict_iter);
 654
 655       if (sym != NULL)
 656         return sym;
 657
 658       /* We have finished iterating the appropriate block of one
 659          symtab.  Now advance to the next symtab and begin iteration
 660          there.  */
 661       ++iterator->idx;
 662       first = 1;
 663     }
 664 }
 665
 666 /* See block.h.  */
 667
 668 struct symbol *
 669 block_iter_match_first (const struct block *block,
 670                         const char *name,
 671                         symbol_compare_ftype *compare,
 672                         struct block_iterator *iterator)
 673 {
 674   initialize_block_iterator (block, iterator);
 675
 676   if (iterator->which == FIRST_LOCAL_BLOCK)
 677     return dict_iter_match_first (block->dict, name, compare,
 678                                   &iterator->dict_iter);
 679
 680   return block_iter_match_step (iterator, name, compare, 1);
 681 }
 682
 683 /* See block.h.  */
 684
 685 struct symbol *
 686 block_iter_match_next (const char *name,
 687                        symbol_compare_ftype *compare,
 688                        struct block_iterator *iterator)
 689 {
 690   if (iterator->which == FIRST_LOCAL_BLOCK)
 691     return dict_iter_match_next (name, compare, &iterator->dict_iter);
 692
 693   return block_iter_match_step (iterator, name, compare, 0);
 694 }