gdb/block.c

   1 /* Block-related functions for the GNU debugger, GDB.
   2
   3    Copyright (C) 2003-2014 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 bound_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.minsym == NULL ? "???"
 220                     : SYMBOL_PRINT_NAME (msym.minsym)));
 221     }
 222
 223   return *slot;
 224 }
 225
 226 /* Return the blockvector immediately containing the innermost lexical block
 227    containing the specified pc value, or 0 if there is none.
 228    Backward compatibility, no section.  */
 229
 230 struct blockvector *
 231 blockvector_for_pc (CORE_ADDR pc, struct block **pblock)
 232 {
 233   return blockvector_for_pc_sect (pc, find_pc_mapped_section (pc),
 234                                   pblock, NULL);
 235 }
 236
 237 /* Return the innermost lexical block containing the specified pc value
 238    in the specified section, or 0 if there is none.  */
 239
 240 struct block *
 241 block_for_pc_sect (CORE_ADDR pc, struct obj_section *section)
 242 {
 243   struct blockvector *bl;
 244   struct block *b;
 245
 246   bl = blockvector_for_pc_sect (pc, section, &b, NULL);
 247   if (bl)
 248     return b;
 249   return 0;
 250 }
 251
 252 /* Return the innermost lexical block containing the specified pc value,
 253    or 0 if there is none.  Backward compatibility, no section.  */
 254
 255 struct block *
 256 block_for_pc (CORE_ADDR pc)
 257 {
 258   return block_for_pc_sect (pc, find_pc_mapped_section (pc));
 259 }
 260
 261 /* Now come some functions designed to deal with C++ namespace issues.
 262    The accessors are safe to use even in the non-C++ case.  */
 263
 264 /* This returns the namespace that BLOCK is enclosed in, or "" if it
 265    isn't enclosed in a namespace at all.  This travels the chain of
 266    superblocks looking for a scope, if necessary.  */
 267
 268 const char *
 269 block_scope (const struct block *block)
 270 {
 271   for (; block != NULL; block = BLOCK_SUPERBLOCK (block))
 272     {
 273       if (BLOCK_NAMESPACE (block) != NULL
 274           && BLOCK_NAMESPACE (block)->scope != NULL)
 275         return BLOCK_NAMESPACE (block)->scope;
 276     }
 277
 278   return "";
 279 }
 280
 281 /* Set BLOCK's scope member to SCOPE; if needed, allocate memory via
 282    OBSTACK.  (It won't make a copy of SCOPE, however, so that already
 283    has to be allocated correctly.)  */
 284
 285 void
 286 block_set_scope (struct block *block, const char *scope,
 287                  struct obstack *obstack)
 288 {
 289   block_initialize_namespace (block, obstack);
 290
 291   BLOCK_NAMESPACE (block)->scope = scope;
 292 }
 293
 294 /* This returns the using directives list associated with BLOCK, if
 295    any.  */
 296
 297 struct using_direct *
 298 block_using (const struct block *block)
 299 {
 300   if (block == NULL || BLOCK_NAMESPACE (block) == NULL)
 301     return NULL;
 302   else
 303     return BLOCK_NAMESPACE (block)->using;
 304 }
 305
 306 /* Set BLOCK's using member to USING; if needed, allocate memory via
 307    OBSTACK.  (It won't make a copy of USING, however, so that already
 308    has to be allocated correctly.)  */
 309
 310 void
 311 block_set_using (struct block *block,
 312                  struct using_direct *using,
 313                  struct obstack *obstack)
 314 {
 315   block_initialize_namespace (block, obstack);
 316
 317   BLOCK_NAMESPACE (block)->using = using;
 318 }
 319
 320 /* If BLOCK_NAMESPACE (block) is NULL, allocate it via OBSTACK and
 321    ititialize its members to zero.  */
 322
 323 static void
 324 block_initialize_namespace (struct block *block, struct obstack *obstack)
 325 {
 326   if (BLOCK_NAMESPACE (block) == NULL)
 327     {
 328       BLOCK_NAMESPACE (block)
 329         = obstack_alloc (obstack, sizeof (struct block_namespace_info));
 330       BLOCK_NAMESPACE (block)->scope = NULL;
 331       BLOCK_NAMESPACE (block)->using = NULL;
 332     }
 333 }
 334
 335 /* Return the static block associated to BLOCK.  Return NULL if block
 336    is NULL or if block is a global block.  */
 337
 338 const struct block *
 339 block_static_block (const struct block *block)
 340 {
 341   if (block == NULL || BLOCK_SUPERBLOCK (block) == NULL)
 342     return NULL;
 343
 344   while (BLOCK_SUPERBLOCK (BLOCK_SUPERBLOCK (block)) != NULL)
 345     block = BLOCK_SUPERBLOCK (block);
 346
 347   return block;
 348 }
 349
 350 /* Return the static block associated to BLOCK.  Return NULL if block
 351    is NULL.  */
 352
 353 const struct block *
 354 block_global_block (const struct block *block)
 355 {
 356   if (block == NULL)
 357     return NULL;
 358
 359   while (BLOCK_SUPERBLOCK (block) != NULL)
 360     block = BLOCK_SUPERBLOCK (block);
 361
 362   return block;
 363 }
 364
 365 /* Allocate a block on OBSTACK, and initialize its elements to
 366    zero/NULL.  This is useful for creating "dummy" blocks that don't
 367    correspond to actual source files.
 368
 369    Warning: it sets the block's BLOCK_DICT to NULL, which isn't a
 370    valid value.  If you really don't want the block to have a
 371    dictionary, then you should subsequently set its BLOCK_DICT to
 372    dict_create_linear (obstack, NULL).  */
 373
 374 struct block *
 375 allocate_block (struct obstack *obstack)
 376 {
 377   struct block *bl = obstack_alloc (obstack, sizeof (struct block));
 378
 379   BLOCK_START (bl) = 0;
 380   BLOCK_END (bl) = 0;
 381   BLOCK_FUNCTION (bl) = NULL;
 382   BLOCK_SUPERBLOCK (bl) = NULL;
 383   BLOCK_DICT (bl) = NULL;
 384   BLOCK_NAMESPACE (bl) = NULL;
 385
 386   return bl;
 387 }
 388
 389 /* Allocate a global block.  */
 390
 391 struct block *
 392 allocate_global_block (struct obstack *obstack)
 393 {
 394   struct global_block *bl = OBSTACK_ZALLOC (obstack, struct global_block);
 395
 396   return &bl->block;
 397 }
 398
 399 /* Set the symtab of the global block.  */
 400
 401 void
 402 set_block_symtab (struct block *block, struct symtab *symtab)
 403 {
 404   struct global_block *gb;
 405
 406   gdb_assert (BLOCK_SUPERBLOCK (block) == NULL);
 407   gb = (struct global_block *) block;
 408   gdb_assert (gb->symtab == NULL);
 409   gb->symtab = symtab;
 410 }
 411
 412 /* Return the symtab of the global block.  */
 413
 414 static struct symtab *
 415 get_block_symtab (const struct block *block)
 416 {
 417   struct global_block *gb;
 418
 419   gdb_assert (BLOCK_SUPERBLOCK (block) == NULL);
 420   gb = (struct global_block *) block;
 421   gdb_assert (gb->symtab != NULL);
 422   return gb->symtab;
 423 }
 424
 425 \f
 426
 427 /* Initialize a block iterator, either to iterate over a single block,
 428    or, for static and global blocks, all the included symtabs as
 429    well.  */
 430
 431 static void
 432 initialize_block_iterator (const struct block *block,
 433                            struct block_iterator *iter)
 434 {
 435   enum block_enum which;
 436   struct symtab *symtab;
 437
 438   iter->idx = -1;
 439
 440   if (BLOCK_SUPERBLOCK (block) == NULL)
 441     {
 442       which = GLOBAL_BLOCK;
 443       symtab = get_block_symtab (block);
 444     }
 445   else if (BLOCK_SUPERBLOCK (BLOCK_SUPERBLOCK (block)) == NULL)
 446     {
 447       which = STATIC_BLOCK;
 448       symtab = get_block_symtab (BLOCK_SUPERBLOCK (block));
 449     }
 450   else
 451     {
 452       iter->d.block = block;
 453       /* A signal value meaning that we're iterating over a single
 454          block.  */
 455       iter->which = FIRST_LOCAL_BLOCK;
 456       return;
 457     }
 458
 459   /* If this is an included symtab, find the canonical includer and
 460      use it instead.  */
 461   while (symtab->user != NULL)
 462     symtab = symtab->user;
 463
 464   /* Putting this check here simplifies the logic of the iterator
 465      functions.  If there are no included symtabs, we only need to
 466      search a single block, so we might as well just do that
 467      directly.  */
 468   if (symtab->includes == NULL)
 469     {
 470       iter->d.block = block;
 471       /* A signal value meaning that we're iterating over a single
 472          block.  */
 473       iter->which = FIRST_LOCAL_BLOCK;
 474     }
 475   else
 476     {
 477       iter->d.symtab = symtab;
 478       iter->which = which;
 479     }
 480 }
 481
 482 /* A helper function that finds the current symtab over whose static
 483    or global block we should iterate.  */
 484
 485 static struct symtab *
 486 find_iterator_symtab (struct block_iterator *iterator)
 487 {
 488   if (iterator->idx == -1)
 489     return iterator->d.symtab;
 490   return iterator->d.symtab->includes[iterator->idx];
 491 }
 492
 493 /* Perform a single step for a plain block iterator, iterating across
 494    symbol tables as needed.  Returns the next symbol, or NULL when
 495    iteration is complete.  */
 496
 497 static struct symbol *
 498 block_iterator_step (struct block_iterator *iterator, int first)
 499 {
 500   struct symbol *sym;
 501
 502   gdb_assert (iterator->which != FIRST_LOCAL_BLOCK);
 503
 504   while (1)
 505     {
 506       if (first)
 507         {
 508           struct symtab *symtab = find_iterator_symtab (iterator);
 509           const struct block *block;
 510
 511           /* Iteration is complete.  */
 512           if (symtab == NULL)
 513             return  NULL;
 514
 515           block = BLOCKVECTOR_BLOCK (BLOCKVECTOR (symtab), iterator->which);
 516           sym = dict_iterator_first (BLOCK_DICT (block), &iterator->dict_iter);
 517         }
 518       else
 519         sym = dict_iterator_next (&iterator->dict_iter);
 520
 521       if (sym != NULL)
 522         return sym;
 523
 524       /* We have finished iterating the appropriate block of one
 525          symtab.  Now advance to the next symtab and begin iteration
 526          there.  */
 527       ++iterator->idx;
 528       first = 1;
 529     }
 530 }
 531
 532 /* See block.h.  */
 533
 534 struct symbol *
 535 block_iterator_first (const struct block *block,
 536                       struct block_iterator *iterator)
 537 {
 538   initialize_block_iterator (block, iterator);
 539
 540   if (iterator->which == FIRST_LOCAL_BLOCK)
 541     return dict_iterator_first (block->dict, &iterator->dict_iter);
 542
 543   return block_iterator_step (iterator, 1);
 544 }
 545
 546 /* See block.h.  */
 547
 548 struct symbol *
 549 block_iterator_next (struct block_iterator *iterator)
 550 {
 551   if (iterator->which == FIRST_LOCAL_BLOCK)
 552     return dict_iterator_next (&iterator->dict_iter);
 553
 554   return block_iterator_step (iterator, 0);
 555 }
 556
 557 /* Perform a single step for a "name" block iterator, iterating across
 558    symbol tables as needed.  Returns the next symbol, or NULL when
 559    iteration is complete.  */
 560
 561 static struct symbol *
 562 block_iter_name_step (struct block_iterator *iterator, const char *name,
 563                       int first)
 564 {
 565   struct symbol *sym;
 566
 567   gdb_assert (iterator->which != FIRST_LOCAL_BLOCK);
 568
 569   while (1)
 570     {
 571       if (first)
 572         {
 573           struct symtab *symtab = find_iterator_symtab (iterator);
 574           const struct block *block;
 575
 576           /* Iteration is complete.  */
 577           if (symtab == NULL)
 578             return  NULL;
 579
 580           block = BLOCKVECTOR_BLOCK (BLOCKVECTOR (symtab), iterator->which);
 581           sym = dict_iter_name_first (BLOCK_DICT (block), name,
 582                                       &iterator->dict_iter);
 583         }
 584       else
 585         sym = dict_iter_name_next (name, &iterator->dict_iter);
 586
 587       if (sym != NULL)
 588         return sym;
 589
 590       /* We have finished iterating the appropriate block of one
 591          symtab.  Now advance to the next symtab and begin iteration
 592          there.  */
 593       ++iterator->idx;
 594       first = 1;
 595     }
 596 }
 597
 598 /* See block.h.  */
 599
 600 struct symbol *
 601 block_iter_name_first (const struct block *block,
 602                        const char *name,
 603                        struct block_iterator *iterator)
 604 {
 605   initialize_block_iterator (block, iterator);
 606
 607   if (iterator->which == FIRST_LOCAL_BLOCK)
 608     return dict_iter_name_first (block->dict, name, &iterator->dict_iter);
 609
 610   return block_iter_name_step (iterator, name, 1);
 611 }
 612
 613 /* See block.h.  */
 614
 615 struct symbol *
 616 block_iter_name_next (const char *name, struct block_iterator *iterator)
 617 {
 618   if (iterator->which == FIRST_LOCAL_BLOCK)
 619     return dict_iter_name_next (name, &iterator->dict_iter);
 620
 621   return block_iter_name_step (iterator, name, 0);
 622 }
 623
 624 /* Perform a single step for a "match" block iterator, iterating
 625    across symbol tables as needed.  Returns the next symbol, or NULL
 626    when iteration is complete.  */
 627
 628 static struct symbol *
 629 block_iter_match_step (struct block_iterator *iterator,
 630                        const char *name,
 631                        symbol_compare_ftype *compare,
 632                        int first)
 633 {
 634   struct symbol *sym;
 635
 636   gdb_assert (iterator->which != FIRST_LOCAL_BLOCK);
 637
 638   while (1)
 639     {
 640       if (first)
 641         {
 642           struct symtab *symtab = find_iterator_symtab (iterator);
 643           const struct block *block;
 644
 645           /* Iteration is complete.  */
 646           if (symtab == NULL)
 647             return  NULL;
 648
 649           block = BLOCKVECTOR_BLOCK (BLOCKVECTOR (symtab), iterator->which);
 650           sym = dict_iter_match_first (BLOCK_DICT (block), name,
 651                                        compare, &iterator->dict_iter);
 652         }
 653       else
 654         sym = dict_iter_match_next (name, compare, &iterator->dict_iter);
 655
 656       if (sym != NULL)
 657         return sym;
 658
 659       /* We have finished iterating the appropriate block of one
 660          symtab.  Now advance to the next symtab and begin iteration
 661          there.  */
 662       ++iterator->idx;
 663       first = 1;
 664     }
 665 }
 666
 667 /* See block.h.  */
 668
 669 struct symbol *
 670 block_iter_match_first (const struct block *block,
 671                         const char *name,
 672                         symbol_compare_ftype *compare,
 673                         struct block_iterator *iterator)
 674 {
 675   initialize_block_iterator (block, iterator);
 676
 677   if (iterator->which == FIRST_LOCAL_BLOCK)
 678     return dict_iter_match_first (block->dict, name, compare,
 679                                   &iterator->dict_iter);
 680
 681   return block_iter_match_step (iterator, name, compare, 1);
 682 }
 683
 684 /* See block.h.  */
 685
 686 struct symbol *
 687 block_iter_match_next (const char *name,
 688                        symbol_compare_ftype *compare,
 689                        struct block_iterator *iterator)
 690 {
 691   if (iterator->which == FIRST_LOCAL_BLOCK)
 692     return dict_iter_match_next (name, compare, &iterator->dict_iter);
 693
 694   return block_iter_match_step (iterator, name, compare, 0);
 695 }