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