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