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