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 /* Number of ranges within a block.  */
 219
 220 #define BLOCK_NRANGES(bl)       (bl)->ranges ().size ()
 221
 222 /* Access range array for block BL.  */
 223
 224 #define BLOCK_RANGE(bl)         (bl)->ranges ().data ()
 225
 226 /* Are all addresses within a block contiguous?  */
 227
 228 #define BLOCK_CONTIGUOUS_P(bl)  ((bl)->ranges ().size () == 0 \
 229                                  || (bl)->ranges ().size () == 1)
 230
 231 /* Define the "entry pc" for a block BL to be the lowest (start) address
 232    for the block when all addresses within the block are contiguous.  If
 233    non-contiguous, then use the start address for the first range in the
 234    block.
 235
 236    At the moment, this almost matches what DWARF specifies as the entry
 237    pc.  (The missing bit is support for DW_AT_entry_pc which should be
 238    preferred over range data and the low_pc.)
 239
 240    Once support for DW_AT_entry_pc is added, I expect that an entry_pc
 241    field will be added to one of these data structures.  Once that's done,
 242    the entry_pc field can be set from the dwarf reader (and other readers
 243    too).  BLOCK_ENTRY_PC can then be redefined to be less DWARF-centric.  */
 244
 245 #define BLOCK_ENTRY_PC(bl)      (BLOCK_CONTIGUOUS_P (bl) \
 246                                  ? bl->start () \
 247                                  : BLOCK_RANGE (bl)[0].start ())
 248
 249 struct blockvector
 250 {
 251   /* Number of blocks in the list.  */
 252   int nblocks;
 253   /* An address map mapping addresses to blocks in this blockvector.
 254      This pointer is zero if the blocks' start and end addresses are
 255      enough.  */
 256   struct addrmap *map;
 257   /* The blocks themselves.  */
 258   struct block *block[1];
 259 };
 260
 261 #define BLOCKVECTOR_NBLOCKS(blocklist) (blocklist)->nblocks
 262 #define BLOCKVECTOR_BLOCK(blocklist,n) (blocklist)->block[n]
 263 #define BLOCKVECTOR_MAP(blocklist) ((blocklist)->map)
 264
 265 /* Return the objfile of BLOCK, which must be non-NULL.  */
 266
 267 extern struct objfile *block_objfile (const struct block *block);
 268
 269 /* Return the architecture of BLOCK, which must be non-NULL.  */
 270
 271 extern struct gdbarch *block_gdbarch (const struct block *block);
 272
 273 extern struct symbol *block_linkage_function (const struct block *);
 274
 275 extern struct symbol *block_containing_function (const struct block *);
 276
 277 extern int block_inlined_p (const struct block *block);
 278
 279 /* Return true if block A is lexically nested within block B, or if a
 280    and b have the same pc range.  Return false otherwise.  If
 281    ALLOW_NESTED is true, then block A is considered to be in block B
 282    if A is in a nested function in B's function.  If ALLOW_NESTED is
 283    false (the default), then blocks in nested functions are not
 284    considered to be contained.  */
 285
 286 extern bool contained_in (const struct block *a, const struct block *b,
 287                           bool allow_nested = false);
 288
 289 extern const struct blockvector *blockvector_for_pc (CORE_ADDR,
 290                                                const struct block **);
 291
 292 extern const struct blockvector *
 293   blockvector_for_pc_sect (CORE_ADDR, struct obj_section *,
 294                            const struct block **, struct compunit_symtab *);
 295
 296 extern int blockvector_contains_pc (const struct blockvector *bv, CORE_ADDR pc);
 297
 298 extern struct call_site *call_site_for_pc (struct gdbarch *gdbarch,
 299                                            CORE_ADDR pc);
 300
 301 extern const struct block *block_for_pc (CORE_ADDR);
 302
 303 extern const struct block *block_for_pc_sect (CORE_ADDR, struct obj_section *);
 304
 305 extern const char *block_scope (const struct block *block);
 306
 307 extern void block_set_scope (struct block *block, const char *scope,
 308                              struct obstack *obstack);
 309
 310 extern struct using_direct *block_using (const struct block *block);
 311
 312 extern void block_set_using (struct block *block,
 313                              struct using_direct *using_decl,
 314                              struct obstack *obstack);
 315
 316 extern const struct block *block_static_block (const struct block *block);
 317
 318 extern const struct block *block_global_block (const struct block *block);
 319
 320 extern struct block *allocate_block (struct obstack *obstack);
 321
 322 extern struct block *allocate_global_block (struct obstack *obstack);
 323
 324 extern void set_block_compunit_symtab (struct block *,
 325                                        struct compunit_symtab *);
 326
 327 /* Return a property to evaluate the static link associated to BLOCK.
 328
 329    In the context of nested functions (available in Pascal, Ada and GNU C, for
 330    instance), a static link (as in DWARF's DW_AT_static_link attribute) for a
 331    function is a way to get the frame corresponding to the enclosing function.
 332
 333    Note that only objfile-owned and function-level blocks can have a static
 334    link.  Return NULL if there is no such property.  */
 335
 336 extern struct dynamic_prop *block_static_link (const struct block *block);
 337
 338 /* A block iterator.  This structure should be treated as though it
 339    were opaque; it is only defined here because we want to support
 340    stack allocation of iterators.  */
 341
 342 struct block_iterator
 343 {
 344   /* If we're iterating over a single block, this holds the block.
 345      Otherwise, it holds the canonical compunit.  */
 346
 347   union
 348   {
 349     struct compunit_symtab *compunit_symtab;
 350     const struct block *block;
 351   } d;
 352
 353   /* If we're iterating over a single block, this is always -1.
 354      Otherwise, it holds the index of the current "included" symtab in
 355      the canonical symtab (that is, d.symtab->includes[idx]), with -1
 356      meaning the canonical symtab itself.  */
 357
 358   int idx;
 359
 360   /* Which block, either static or global, to iterate over.  If this
 361      is FIRST_LOCAL_BLOCK, then we are iterating over a single block.
 362      This is used to select which field of 'd' is in use.  */
 363
 364   enum block_enum which;
 365
 366   /* The underlying multidictionary iterator.  */
 367
 368   struct mdict_iterator mdict_iter;
 369 };
 370
 371 /* Initialize ITERATOR to point at the first symbol in BLOCK, and
 372    return that first symbol, or NULL if BLOCK is empty.  */
 373
 374 extern struct symbol *block_iterator_first (const struct block *block,
 375                                             struct block_iterator *iterator);
 376
 377 /* Advance ITERATOR, and return the next symbol, or NULL if there are
 378    no more symbols.  Don't call this if you've previously received
 379    NULL from block_iterator_first or block_iterator_next on this
 380    iteration.  */
 381
 382 extern struct symbol *block_iterator_next (struct block_iterator *iterator);
 383
 384 /* Initialize ITERATOR to point at the first symbol in BLOCK whose
 385    search_name () matches NAME, and return that first symbol, or
 386    NULL if there are no such symbols.  */
 387
 388 extern struct symbol *block_iter_match_first (const struct block *block,
 389                                               const lookup_name_info &name,
 390                                               struct block_iterator *iterator);
 391
 392 /* Advance ITERATOR to point at the next symbol in BLOCK whose
 393    search_name () matches NAME, or NULL if there are no more such
 394    symbols.  Don't call this if you've previously received NULL from
 395    block_iterator_match_first or block_iterator_match_next on this
 396    iteration.  And don't call it unless ITERATOR was created by a
 397    previous call to block_iter_match_first with the same NAME.  */
 398
 399 extern struct symbol *block_iter_match_next
 400   (const lookup_name_info &name, struct block_iterator *iterator);
 401
 402 /* Return true if symbol A is the best match possible for DOMAIN.  */
 403
 404 extern bool best_symbol (struct symbol *a, const domain_enum domain);
 405
 406 /* Return symbol B if it is a better match than symbol A for DOMAIN.
 407    Otherwise return A.  */
 408
 409 extern struct symbol *better_symbol (struct symbol *a, struct symbol *b,
 410                                      const domain_enum domain);
 411
 412 /* Search BLOCK for symbol NAME in DOMAIN.  */
 413
 414 extern struct symbol *block_lookup_symbol (const struct block *block,
 415                                            const char *name,
 416                                            symbol_name_match_type match_type,
 417                                            const domain_enum domain);
 418
 419 /* Search BLOCK for symbol NAME in DOMAIN but only in primary symbol table of
 420    BLOCK.  BLOCK must be STATIC_BLOCK or GLOBAL_BLOCK.  Function is useful if
 421    one iterates all global/static blocks of an objfile.  */
 422
 423 extern struct symbol *block_lookup_symbol_primary (const struct block *block,
 424                                                    const char *name,
 425                                                    const domain_enum domain);
 426
 427 /* The type of the MATCHER argument to block_find_symbol.  */
 428
 429 typedef int (block_symbol_matcher_ftype) (struct symbol *, void *);
 430
 431 /* Find symbol NAME in BLOCK and in DOMAIN that satisfies MATCHER.
 432    DATA is passed unchanged to MATCHER.
 433    BLOCK must be STATIC_BLOCK or GLOBAL_BLOCK.  */
 434
 435 extern struct symbol *block_find_symbol (const struct block *block,
 436                                          const char *name,
 437                                          const domain_enum domain,
 438                                          block_symbol_matcher_ftype *matcher,
 439                                          void *data);
 440
 441 /* A matcher function for block_find_symbol to find only symbols with
 442    non-opaque types.  */
 443
 444 extern int block_find_non_opaque_type (struct symbol *sym, void *data);
 445
 446 /* A matcher function for block_find_symbol to prefer symbols with
 447    non-opaque types.  The way to use this function is as follows:
 448
 449    struct symbol *with_opaque = NULL;
 450    struct symbol *sym
 451      = block_find_symbol (block, name, domain,
 452                           block_find_non_opaque_type_preferred, &with_opaque);
 453
 454    At this point if SYM is non-NULL then a non-opaque type has been found.
 455    Otherwise, if WITH_OPAQUE is non-NULL then an opaque type has been found.
 456    Otherwise, the symbol was not found.  */
 457
 458 extern int block_find_non_opaque_type_preferred (struct symbol *sym,
 459                                                  void *data);
 460
 461 /* Macro to loop through all symbols in BLOCK, in no particular
 462    order.  ITER helps keep track of the iteration, and must be a
 463    struct block_iterator.  SYM points to the current symbol.  */
 464
 465 #define ALL_BLOCK_SYMBOLS(block, iter, sym)             \
 466   for ((sym) = block_iterator_first ((block), &(iter)); \
 467        (sym);                                           \
 468        (sym) = block_iterator_next (&(iter)))
 469
 470 /* Macro to loop through all symbols in BLOCK with a name that matches
 471    NAME, in no particular order.  ITER helps keep track of the
 472    iteration, and must be a struct block_iterator.  SYM points to the
 473    current symbol.  */
 474
 475 #define ALL_BLOCK_SYMBOLS_WITH_NAME(block, name, iter, sym)             \
 476   for ((sym) = block_iter_match_first ((block), (name), &(iter));       \
 477        (sym) != NULL;                                                   \
 478        (sym) = block_iter_match_next ((name), &(iter)))
 479
 480 /* Given a vector of pairs, allocate and build an obstack allocated
 481    blockranges struct for a block.  */
 482 struct blockranges *make_blockranges (struct objfile *objfile,
 483                                       const std::vector<blockrange> &rangevec);
 484
 485 #endif /* BLOCK_H */