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