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   /* Addresses in the executable code that are in this block.  */
 171
 172   CORE_ADDR m_start;
 173   CORE_ADDR m_end;
 174
 175   /* The symbol that names this block, if the block is the body of a
 176      function (real or inlined); otherwise, zero.  */
 177
 178   struct symbol *m_function;
 179
 180   /* The `struct block' for the containing block, or 0 if none.
 181
 182      The superblock of a top-level local block (i.e. a function in the
 183      case of C) is the STATIC_BLOCK.  The superblock of the
 184      STATIC_BLOCK is the GLOBAL_BLOCK.  */
 185
 186   const struct block *m_superblock;
 187
 188   /* This is used to store the symbols in the block.  */
 189
 190   struct multidictionary *m_multidict;
 191
 192   /* Contains information about namespace-related info relevant to this block:
 193      using directives and the current namespace scope.  */
 194
 195   struct block_namespace_info *m_namespace_info;
 196
 197   /* Address ranges for blocks with non-contiguous ranges.  If this
 198      is NULL, then there is only one range which is specified by
 199      startaddr and endaddr above.  */
 200
 201   struct blockranges *m_ranges;
 202 };
 203
 204 /* The global block is singled out so that we can provide a back-link
 205    to the compunit symtab.  */
 206
 207 struct global_block
 208 {
 209   /* The block.  */
 210
 211   struct block block;
 212
 213   /* This holds a pointer to the compunit symtab holding this block.  */
 214
 215   struct compunit_symtab *compunit_symtab;
 216 };
 217
 218 /* Are all addresses within a block contiguous?  */
 219
 220 #define BLOCK_CONTIGUOUS_P(bl)  ((bl)->ranges ().size () == 0 \
 221                                  || (bl)->ranges ().size () == 1)
 222
 223 /* Define the "entry pc" for a block BL to be the lowest (start) address
 224    for the block when all addresses within the block are contiguous.  If
 225    non-contiguous, then use the start address for the first range in the
 226    block.
 227
 228    At the moment, this almost matches what DWARF specifies as the entry
 229    pc.  (The missing bit is support for DW_AT_entry_pc which should be
 230    preferred over range data and the low_pc.)
 231
 232    Once support for DW_AT_entry_pc is added, I expect that an entry_pc
 233    field will be added to one of these data structures.  Once that's done,
 234    the entry_pc field can be set from the dwarf reader (and other readers
 235    too).  BLOCK_ENTRY_PC can then be redefined to be less DWARF-centric.  */
 236
 237 #define BLOCK_ENTRY_PC(bl)      (BLOCK_CONTIGUOUS_P (bl) \
 238                                  ? bl->start () \
 239                                  : bl->ranges ()[0].start ())
 240
 241 struct blockvector
 242 {
 243   /* Number of blocks in the list.  */
 244   int nblocks;
 245   /* An address map mapping addresses to blocks in this blockvector.
 246      This pointer is zero if the blocks' start and end addresses are
 247      enough.  */
 248   struct addrmap *map;
 249   /* The blocks themselves.  */
 250   struct block *block[1];
 251 };
 252
 253 #define BLOCKVECTOR_NBLOCKS(blocklist) (blocklist)->nblocks
 254 #define BLOCKVECTOR_BLOCK(blocklist,n) (blocklist)->block[n]
 255 #define BLOCKVECTOR_MAP(blocklist) ((blocklist)->map)
 256
 257 /* Return the objfile of BLOCK, which must be non-NULL.  */
 258
 259 extern struct objfile *block_objfile (const struct block *block);
 260
 261 /* Return the architecture of BLOCK, which must be non-NULL.  */
 262
 263 extern struct gdbarch *block_gdbarch (const struct block *block);
 264
 265 extern struct symbol *block_linkage_function (const struct block *);
 266
 267 extern struct symbol *block_containing_function (const struct block *);
 268
 269 extern int block_inlined_p (const struct block *block);
 270
 271 /* Return true if block A is lexically nested within block B, or if a
 272    and b have the same pc range.  Return false otherwise.  If
 273    ALLOW_NESTED is true, then block A is considered to be in block B
 274    if A is in a nested function in B's function.  If ALLOW_NESTED is
 275    false (the default), then blocks in nested functions are not
 276    considered to be contained.  */
 277
 278 extern bool contained_in (const struct block *a, const struct block *b,
 279                           bool allow_nested = false);
 280
 281 extern const struct blockvector *blockvector_for_pc (CORE_ADDR,
 282                                                const struct block **);
 283
 284 extern const struct blockvector *
 285   blockvector_for_pc_sect (CORE_ADDR, struct obj_section *,
 286                            const struct block **, struct compunit_symtab *);
 287
 288 extern int blockvector_contains_pc (const struct blockvector *bv, CORE_ADDR pc);
 289
 290 extern struct call_site *call_site_for_pc (struct gdbarch *gdbarch,
 291                                            CORE_ADDR pc);
 292
 293 extern const struct block *block_for_pc (CORE_ADDR);
 294
 295 extern const struct block *block_for_pc_sect (CORE_ADDR, struct obj_section *);
 296
 297 extern const char *block_scope (const struct block *block);
 298
 299 extern void block_set_scope (struct block *block, const char *scope,
 300                              struct obstack *obstack);
 301
 302 extern struct using_direct *block_using (const struct block *block);
 303
 304 extern void block_set_using (struct block *block,
 305                              struct using_direct *using_decl,
 306                              struct obstack *obstack);
 307
 308 extern const struct block *block_static_block (const struct block *block);
 309
 310 extern const struct block *block_global_block (const struct block *block);
 311
 312 extern struct block *allocate_block (struct obstack *obstack);
 313
 314 extern struct block *allocate_global_block (struct obstack *obstack);
 315
 316 extern void set_block_compunit_symtab (struct block *,
 317                                        struct compunit_symtab *);
 318
 319 /* Return a property to evaluate the static link associated to BLOCK.
 320
 321    In the context of nested functions (available in Pascal, Ada and GNU C, for
 322    instance), a static link (as in DWARF's DW_AT_static_link attribute) for a
 323    function is a way to get the frame corresponding to the enclosing function.
 324
 325    Note that only objfile-owned and function-level blocks can have a static
 326    link.  Return NULL if there is no such property.  */
 327
 328 extern struct dynamic_prop *block_static_link (const struct block *block);
 329
 330 /* A block iterator.  This structure should be treated as though it
 331    were opaque; it is only defined here because we want to support
 332    stack allocation of iterators.  */
 333
 334 struct block_iterator
 335 {
 336   /* If we're iterating over a single block, this holds the block.
 337      Otherwise, it holds the canonical compunit.  */
 338
 339   union
 340   {
 341     struct compunit_symtab *compunit_symtab;
 342     const struct block *block;
 343   } d;
 344
 345   /* If we're iterating over a single block, this is always -1.
 346      Otherwise, it holds the index of the current "included" symtab in
 347      the canonical symtab (that is, d.symtab->includes[idx]), with -1
 348      meaning the canonical symtab itself.  */
 349
 350   int idx;
 351
 352   /* Which block, either static or global, to iterate over.  If this
 353      is FIRST_LOCAL_BLOCK, then we are iterating over a single block.
 354      This is used to select which field of 'd' is in use.  */
 355
 356   enum block_enum which;
 357
 358   /* The underlying multidictionary iterator.  */
 359
 360   struct mdict_iterator mdict_iter;
 361 };
 362
 363 /* Initialize ITERATOR to point at the first symbol in BLOCK, and
 364    return that first symbol, or NULL if BLOCK is empty.  */
 365
 366 extern struct symbol *block_iterator_first (const struct block *block,
 367                                             struct block_iterator *iterator);
 368
 369 /* Advance ITERATOR, and return the next symbol, or NULL if there are
 370    no more symbols.  Don't call this if you've previously received
 371    NULL from block_iterator_first or block_iterator_next on this
 372    iteration.  */
 373
 374 extern struct symbol *block_iterator_next (struct block_iterator *iterator);
 375
 376 /* Initialize ITERATOR to point at the first symbol in BLOCK whose
 377    search_name () matches NAME, and return that first symbol, or
 378    NULL if there are no such symbols.  */
 379
 380 extern struct symbol *block_iter_match_first (const struct block *block,
 381                                               const lookup_name_info &name,
 382                                               struct block_iterator *iterator);
 383
 384 /* Advance ITERATOR to point at the next symbol in BLOCK whose
 385    search_name () matches NAME, or NULL if there are no more such
 386    symbols.  Don't call this if you've previously received NULL from
 387    block_iterator_match_first or block_iterator_match_next on this
 388    iteration.  And don't call it unless ITERATOR was created by a
 389    previous call to block_iter_match_first with the same NAME.  */
 390
 391 extern struct symbol *block_iter_match_next
 392   (const lookup_name_info &name, struct block_iterator *iterator);
 393
 394 /* Return true if symbol A is the best match possible for DOMAIN.  */
 395
 396 extern bool best_symbol (struct symbol *a, const domain_enum domain);
 397
 398 /* Return symbol B if it is a better match than symbol A for DOMAIN.
 399    Otherwise return A.  */
 400
 401 extern struct symbol *better_symbol (struct symbol *a, struct symbol *b,
 402                                      const domain_enum domain);
 403
 404 /* Search BLOCK for symbol NAME in DOMAIN.  */
 405
 406 extern struct symbol *block_lookup_symbol (const struct block *block,
 407                                            const char *name,
 408                                            symbol_name_match_type match_type,
 409                                            const domain_enum domain);
 410
 411 /* Search BLOCK for symbol NAME in DOMAIN but only in primary symbol table of
 412    BLOCK.  BLOCK must be STATIC_BLOCK or GLOBAL_BLOCK.  Function is useful if
 413    one iterates all global/static blocks of an objfile.  */
 414
 415 extern struct symbol *block_lookup_symbol_primary (const struct block *block,
 416                                                    const char *name,
 417                                                    const domain_enum domain);
 418
 419 /* The type of the MATCHER argument to block_find_symbol.  */
 420
 421 typedef int (block_symbol_matcher_ftype) (struct symbol *, void *);
 422
 423 /* Find symbol NAME in BLOCK and in DOMAIN that satisfies MATCHER.
 424    DATA is passed unchanged to MATCHER.
 425    BLOCK must be STATIC_BLOCK or GLOBAL_BLOCK.  */
 426
 427 extern struct symbol *block_find_symbol (const struct block *block,
 428                                          const char *name,
 429                                          const domain_enum domain,
 430                                          block_symbol_matcher_ftype *matcher,
 431                                          void *data);
 432
 433 /* A matcher function for block_find_symbol to find only symbols with
 434    non-opaque types.  */
 435
 436 extern int block_find_non_opaque_type (struct symbol *sym, void *data);
 437
 438 /* A matcher function for block_find_symbol to prefer symbols with
 439    non-opaque types.  The way to use this function is as follows:
 440
 441    struct symbol *with_opaque = NULL;
 442    struct symbol *sym
 443      = block_find_symbol (block, name, domain,
 444                           block_find_non_opaque_type_preferred, &with_opaque);
 445
 446    At this point if SYM is non-NULL then a non-opaque type has been found.
 447    Otherwise, if WITH_OPAQUE is non-NULL then an opaque type has been found.
 448    Otherwise, the symbol was not found.  */
 449
 450 extern int block_find_non_opaque_type_preferred (struct symbol *sym,
 451                                                  void *data);
 452
 453 /* Macro to loop through all symbols in BLOCK, in no particular
 454    order.  ITER helps keep track of the iteration, and must be a
 455    struct block_iterator.  SYM points to the current symbol.  */
 456
 457 #define ALL_BLOCK_SYMBOLS(block, iter, sym)             \
 458   for ((sym) = block_iterator_first ((block), &(iter)); \
 459        (sym);                                           \
 460        (sym) = block_iterator_next (&(iter)))
 461
 462 /* Macro to loop through all symbols in BLOCK with a name that matches
 463    NAME, in no particular order.  ITER helps keep track of the
 464    iteration, and must be a struct block_iterator.  SYM points to the
 465    current symbol.  */
 466
 467 #define ALL_BLOCK_SYMBOLS_WITH_NAME(block, name, iter, sym)             \
 468   for ((sym) = block_iter_match_first ((block), (name), &(iter));       \
 469        (sym) != NULL;                                                   \
 470        (sym) = block_iter_match_next ((name), &(iter)))
 471
 472 /* Given a vector of pairs, allocate and build an obstack allocated
 473    blockranges struct for a block.  */
 474 struct blockranges *make_blockranges (struct objfile *objfile,
 475                                       const std::vector<blockrange> &rangevec);
 476
 477 #endif /* BLOCK_H */