gdb/block.h

   1 /* Code dealing with blocks for GDB.
   2
   3    Copyright (C) 2003-2022 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 #ifndef BLOCK_H
  21 #define BLOCK_H
  22
  23 #include "dictionary.h"
  24 #include "gdbsupport/array-view.h"
  25
  26 /* Opaque declarations.  */
  27
  28 struct symbol;
  29 struct compunit_symtab;
  30 struct block_namespace_info;
  31 struct using_direct;
  32 struct obstack;
  33 struct addrmap;
  34
  35 /* Blocks can occupy non-contiguous address ranges.  When this occurs,
  36    startaddr and endaddr within struct block (still) specify the lowest
  37    and highest addresses of all ranges, but each individual range is
  38    specified by the addresses in struct blockrange.  */
  39
  40 struct blockrange
  41 {
  42   blockrange (CORE_ADDR start, CORE_ADDR end)
  43     : m_start (start),
  44       m_end (end)
  45   {
  46   }
  47
  48   /* Return this blockrange's start address.  */
  49   CORE_ADDR start () const
  50   { return m_start; }
  51
  52   /* Set this blockrange's start address.  */
  53   void set_start (CORE_ADDR start)
  54   { m_start = start; }
  55
  56   /* Return this blockrange's end address.  */
  57   CORE_ADDR end () const
  58   { return m_end; }
  59
  60   /* Set this blockrange's end address.  */
  61   void set_end (CORE_ADDR end)
  62   { m_end = end; }
  63
  64   /* Lowest address in this range.  */
  65
  66   CORE_ADDR m_start;
  67
  68   /* One past the highest address in the range.  */
  69
  70   CORE_ADDR m_end;
  71 };
  72
  73 /* Two or more non-contiguous ranges in the same order as that provided
  74    via the debug info.  */
  75
  76 struct blockranges
  77 {
  78   int nranges;
  79   struct blockrange range[1];
  80 };
  81
  82 /* All of the name-scope contours of the program
  83    are represented by `struct block' objects.
  84    All of these objects are pointed to by the blockvector.
  85
  86    Each block represents one name scope.
  87    Each lexical context has its own block.
  88
  89    The blockvector begins with some special blocks.
  90    The GLOBAL_BLOCK contains all the symbols defined in this compilation
  91    whose scope is the entire program linked together.
  92    The STATIC_BLOCK contains all the symbols whose scope is the
  93    entire compilation excluding other separate compilations.
  94    Blocks starting with the FIRST_LOCAL_BLOCK are not special.
  95
  96    Each block records a range of core addresses for the code that
  97    is in the scope of the block.  The STATIC_BLOCK and GLOBAL_BLOCK
  98    give, for the range of code, the entire range of code produced
  99    by the compilation that the symbol segment belongs to.
 100
 101    The blocks appear in the blockvector
 102    in order of increasing starting-address,
 103    and, within that, in order of decreasing ending-address.
 104
 105    This implies that within the body of one function
 106    the blocks appear in the order of a depth-first tree walk.  */
 107
 108 struct block
 109 {
 110   /* Return this block's start address.  */
 111   CORE_ADDR start () const
 112   { return m_start; }
 113
 114   /* Set this block's start address.  */
 115   void set_start (CORE_ADDR start)
 116   { m_start = start; }
 117
 118   /* Return this block's end address.  */
 119   CORE_ADDR end () const
 120   { return m_end; }
 121
 122   /* Set this block's end address.  */
 123   void set_end (CORE_ADDR end)
 124   { m_end = end; }
 125
 126   /* Return this block's function symbol.  */
 127   symbol *function () const
 128   { return m_function; }
 129
 130   /* Set this block's function symbol.  */
 131   void set_function (symbol *function)
 132   { m_function = function; }
 133
 134   /* Return this block's superblock.  */
 135   const block *superblock () const
 136   { return m_superblock; }
 137
 138   /* Set this block's superblock.  */
 139   void set_superblock (const block *superblock)
 140   { m_superblock = superblock; }
 141
 142   /* Return this block's multidict.  */
 143   multidictionary *multidict () const
 144   { return m_multidict; }
 145
 146   /* Set this block's multidict.  */
 147   void set_multidict (multidictionary *multidict)
 148   { m_multidict = multidict; }
 149
 150   /* Return this block's namespace info.  */
 151   block_namespace_info *namespace_info () const
 152   { return m_namespace_info; }
 153
 154   /* Set this block's namespace info.  */
 155   void set_namespace_info (block_namespace_info *namespace_info)
 156   { m_namespace_info = namespace_info; }
 157
 158   /* Return a view on this block's ranges.  */
 159   gdb::array_view<blockrange> ranges ()
 160   { return gdb::make_array_view (m_ranges->range, m_ranges->nranges); }
 161
 162   /* Const version of the above.  */
 163   gdb::array_view<const blockrange> ranges () const
 164   { return gdb::make_array_view (m_ranges->range, m_ranges->nranges); }
 165
 166   /* Set this block's ranges array.  */
 167   void set_ranges (blockranges *ranges)
 168   { m_ranges = ranges; }
 169
 170   /* Return true if all addresses within this block are contiguous.  */
 171   bool is_contiguous () const
 172   { return this->ranges ().size () <= 1; }
 173
 174   /* Return the "entry PC" of this block.
 175
 176      The entry PC is the lowest (start) address for the block when all addresses
 177      within the block are contiguous.  If non-contiguous, then use the start
 178      address for the first range in the block.
 179
 180      At the moment, this almost matches what DWARF specifies as the entry
 181      pc.  (The missing bit is support for DW_AT_entry_pc which should be
 182      preferred over range data and the low_pc.)
 183
 184      Once support for DW_AT_entry_pc is added, I expect that an entry_pc
 185      field will be added to one of these data structures.  Once that's done,
 186      the entry_pc field can be set from the dwarf reader (and other readers
 187      too).  ENTRY_PC can then be redefined to be less DWARF-centric.  */
 188
 189   CORE_ADDR entry_pc () const
 190   {
 191     if (this->is_contiguous ())
 192       return this->start ();
 193     else
 194       return this->ranges ()[0].start ();
 195   }
 196
 197   /* Addresses in the executable code that are in this block.  */
 198
 199   CORE_ADDR m_start;
 200   CORE_ADDR m_end;
 201
 202   /* The symbol that names this block, if the block is the body of a
 203      function (real or inlined); otherwise, zero.  */
 204
 205   struct symbol *m_function;
 206
 207   /* The `struct block' for the containing block, or 0 if none.
 208
 209      The superblock of a top-level local block (i.e. a function in the
 210      case of C) is the STATIC_BLOCK.  The superblock of the
 211      STATIC_BLOCK is the GLOBAL_BLOCK.  */
 212
 213   const struct block *m_superblock;
 214
 215   /* This is used to store the symbols in the block.  */
 216
 217   struct multidictionary *m_multidict;
 218
 219   /* Contains information about namespace-related info relevant to this block:
 220      using directives and the current namespace scope.  */
 221
 222   struct block_namespace_info *m_namespace_info;
 223
 224   /* Address ranges for blocks with non-contiguous ranges.  If this
 225      is NULL, then there is only one range which is specified by
 226      startaddr and endaddr above.  */
 227
 228   struct blockranges *m_ranges;
 229 };
 230
 231 /* The global block is singled out so that we can provide a back-link
 232    to the compunit symtab.  */
 233
 234 struct global_block
 235 {
 236   /* The block.  */
 237
 238   struct block block;
 239
 240   /* This holds a pointer to the compunit symtab holding this block.  */
 241
 242   struct compunit_symtab *compunit_symtab;
 243 };
 244
 245 struct blockvector
 246 {
 247   /* Number of blocks in the list.  */
 248   int nblocks;
 249   /* An address map mapping addresses to blocks in this blockvector.
 250      This pointer is zero if the blocks' start and end addresses are
 251      enough.  */
 252   struct addrmap *map;
 253   /* The blocks themselves.  */
 254   struct block *block[1];
 255 };
 256
 257 #define BLOCKVECTOR_NBLOCKS(blocklist) (blocklist)->nblocks
 258 #define BLOCKVECTOR_BLOCK(blocklist,n) (blocklist)->block[n]
 259 #define BLOCKVECTOR_MAP(blocklist) ((blocklist)->map)
 260
 261 /* Return the objfile of BLOCK, which must be non-NULL.  */
 262
 263 extern struct objfile *block_objfile (const struct block *block);
 264
 265 /* Return the architecture of BLOCK, which must be non-NULL.  */
 266
 267 extern struct gdbarch *block_gdbarch (const struct block *block);
 268
 269 extern struct symbol *block_linkage_function (const struct block *);
 270
 271 extern struct symbol *block_containing_function (const struct block *);
 272
 273 extern int block_inlined_p (const struct block *block);
 274
 275 /* Return true if block A is lexically nested within block B, or if a
 276    and b have the same pc range.  Return false otherwise.  If
 277    ALLOW_NESTED is true, then block A is considered to be in block B
 278    if A is in a nested function in B's function.  If ALLOW_NESTED is
 279    false (the default), then blocks in nested functions are not
 280    considered to be contained.  */
 281
 282 extern bool contained_in (const struct block *a, const struct block *b,
 283                           bool allow_nested = false);
 284
 285 extern const struct blockvector *blockvector_for_pc (CORE_ADDR,
 286                                                const struct block **);
 287
 288 extern const struct blockvector *
 289   blockvector_for_pc_sect (CORE_ADDR, struct obj_section *,
 290                            const struct block **, struct compunit_symtab *);
 291
 292 extern int blockvector_contains_pc (const struct blockvector *bv, CORE_ADDR pc);
 293
 294 extern struct call_site *call_site_for_pc (struct gdbarch *gdbarch,
 295                                            CORE_ADDR pc);
 296
 297 extern const struct block *block_for_pc (CORE_ADDR);
 298
 299 extern const struct block *block_for_pc_sect (CORE_ADDR, struct obj_section *);
 300
 301 extern const char *block_scope (const struct block *block);
 302
 303 extern void block_set_scope (struct block *block, const char *scope,
 304                              struct obstack *obstack);
 305
 306 extern struct using_direct *block_using (const struct block *block);
 307
 308 extern void block_set_using (struct block *block,
 309                              struct using_direct *using_decl,
 310                              struct obstack *obstack);
 311
 312 extern const struct block *block_static_block (const struct block *block);
 313
 314 extern const struct block *block_global_block (const struct block *block);
 315
 316 extern struct block *allocate_block (struct obstack *obstack);
 317
 318 extern struct block *allocate_global_block (struct obstack *obstack);
 319
 320 extern void set_block_compunit_symtab (struct block *,
 321                                        struct compunit_symtab *);
 322
 323 /* Return a property to evaluate the static link associated to BLOCK.
 324
 325    In the context of nested functions (available in Pascal, Ada and GNU C, for
 326    instance), a static link (as in DWARF's DW_AT_static_link attribute) for a
 327    function is a way to get the frame corresponding to the enclosing function.
 328
 329    Note that only objfile-owned and function-level blocks can have a static
 330    link.  Return NULL if there is no such property.  */
 331
 332 extern struct dynamic_prop *block_static_link (const struct block *block);
 333
 334 /* A block iterator.  This structure should be treated as though it
 335    were opaque; it is only defined here because we want to support
 336    stack allocation of iterators.  */
 337
 338 struct block_iterator
 339 {
 340   /* If we're iterating over a single block, this holds the block.
 341      Otherwise, it holds the canonical compunit.  */
 342
 343   union
 344   {
 345     struct compunit_symtab *compunit_symtab;
 346     const struct block *block;
 347   } d;
 348
 349   /* If we're iterating over a single block, this is always -1.
 350      Otherwise, it holds the index of the current "included" symtab in
 351      the canonical symtab (that is, d.symtab->includes[idx]), with -1
 352      meaning the canonical symtab itself.  */
 353
 354   int idx;
 355
 356   /* Which block, either static or global, to iterate over.  If this
 357      is FIRST_LOCAL_BLOCK, then we are iterating over a single block.
 358      This is used to select which field of 'd' is in use.  */
 359
 360   enum block_enum which;
 361
 362   /* The underlying multidictionary iterator.  */
 363
 364   struct mdict_iterator mdict_iter;
 365 };
 366
 367 /* Initialize ITERATOR to point at the first symbol in BLOCK, and
 368    return that first symbol, or NULL if BLOCK is empty.  */
 369
 370 extern struct symbol *block_iterator_first (const struct block *block,
 371                                             struct block_iterator *iterator);
 372
 373 /* Advance ITERATOR, and return the next symbol, or NULL if there are
 374    no more symbols.  Don't call this if you've previously received
 375    NULL from block_iterator_first or block_iterator_next on this
 376    iteration.  */
 377
 378 extern struct symbol *block_iterator_next (struct block_iterator *iterator);
 379
 380 /* Initialize ITERATOR to point at the first symbol in BLOCK whose
 381    search_name () matches NAME, and return that first symbol, or
 382    NULL if there are no such symbols.  */
 383
 384 extern struct symbol *block_iter_match_first (const struct block *block,
 385                                               const lookup_name_info &name,
 386                                               struct block_iterator *iterator);
 387
 388 /* Advance ITERATOR to point at the next symbol in BLOCK whose
 389    search_name () matches NAME, or NULL if there are no more such
 390    symbols.  Don't call this if you've previously received NULL from
 391    block_iterator_match_first or block_iterator_match_next on this
 392    iteration.  And don't call it unless ITERATOR was created by a
 393    previous call to block_iter_match_first with the same NAME.  */
 394
 395 extern struct symbol *block_iter_match_next
 396   (const lookup_name_info &name, struct block_iterator *iterator);
 397
 398 /* Return true if symbol A is the best match possible for DOMAIN.  */
 399
 400 extern bool best_symbol (struct symbol *a, const domain_enum domain);
 401
 402 /* Return symbol B if it is a better match than symbol A for DOMAIN.
 403    Otherwise return A.  */
 404
 405 extern struct symbol *better_symbol (struct symbol *a, struct symbol *b,
 406                                      const domain_enum domain);
 407
 408 /* Search BLOCK for symbol NAME in DOMAIN.  */
 409
 410 extern struct symbol *block_lookup_symbol (const struct block *block,
 411                                            const char *name,
 412                                            symbol_name_match_type match_type,
 413                                            const domain_enum domain);
 414
 415 /* Search BLOCK for symbol NAME in DOMAIN but only in primary symbol table of
 416    BLOCK.  BLOCK must be STATIC_BLOCK or GLOBAL_BLOCK.  Function is useful if
 417    one iterates all global/static blocks of an objfile.  */
 418
 419 extern struct symbol *block_lookup_symbol_primary (const struct block *block,
 420                                                    const char *name,
 421                                                    const domain_enum domain);
 422
 423 /* The type of the MATCHER argument to block_find_symbol.  */
 424
 425 typedef int (block_symbol_matcher_ftype) (struct symbol *, void *);
 426
 427 /* Find symbol NAME in BLOCK and in DOMAIN that satisfies MATCHER.
 428    DATA is passed unchanged to MATCHER.
 429    BLOCK must be STATIC_BLOCK or GLOBAL_BLOCK.  */
 430
 431 extern struct symbol *block_find_symbol (const struct block *block,
 432                                          const char *name,
 433                                          const domain_enum domain,
 434                                          block_symbol_matcher_ftype *matcher,
 435                                          void *data);
 436
 437 /* A matcher function for block_find_symbol to find only symbols with
 438    non-opaque types.  */
 439
 440 extern int block_find_non_opaque_type (struct symbol *sym, void *data);
 441
 442 /* A matcher function for block_find_symbol to prefer symbols with
 443    non-opaque types.  The way to use this function is as follows:
 444
 445    struct symbol *with_opaque = NULL;
 446    struct symbol *sym
 447      = block_find_symbol (block, name, domain,
 448                           block_find_non_opaque_type_preferred, &with_opaque);
 449
 450    At this point if SYM is non-NULL then a non-opaque type has been found.
 451    Otherwise, if WITH_OPAQUE is non-NULL then an opaque type has been found.
 452    Otherwise, the symbol was not found.  */
 453
 454 extern int block_find_non_opaque_type_preferred (struct symbol *sym,
 455                                                  void *data);
 456
 457 /* Macro to loop through all symbols in BLOCK, in no particular
 458    order.  ITER helps keep track of the iteration, and must be a
 459    struct block_iterator.  SYM points to the current symbol.  */
 460
 461 #define ALL_BLOCK_SYMBOLS(block, iter, sym)             \
 462   for ((sym) = block_iterator_first ((block), &(iter)); \
 463        (sym);                                           \
 464        (sym) = block_iterator_next (&(iter)))
 465
 466 /* Macro to loop through all symbols in BLOCK with a name that matches
 467    NAME, in no particular order.  ITER helps keep track of the
 468    iteration, and must be a struct block_iterator.  SYM points to the
 469    current symbol.  */
 470
 471 #define ALL_BLOCK_SYMBOLS_WITH_NAME(block, name, iter, sym)             \
 472   for ((sym) = block_iter_match_first ((block), (name), &(iter));       \
 473        (sym) != NULL;                                                   \
 474        (sym) = block_iter_match_next ((name), &(iter)))
 475
 476 /* Given a vector of pairs, allocate and build an obstack allocated
 477    blockranges struct for a block.  */
 478 struct blockranges *make_blockranges (struct objfile *objfile,
 479                                       const std::vector<blockrange> &rangevec);
 480
 481 #endif /* BLOCK_H */