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