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