gdb/block.h

   1 /* Code dealing with blocks for GDB.
   2
   3    Copyright (C) 2003-2020 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
  94   /* Addresses in the executable code that are in this block.  */
  95
  96   CORE_ADDR startaddr;
  97   CORE_ADDR endaddr;
  98
  99   /* The symbol that names this block, if the block is the body of a
 100      function (real or inlined); otherwise, zero.  */
 101
 102   struct symbol *function;
 103
 104   /* The `struct block' for the containing block, or 0 if none.
 105
 106      The superblock of a top-level local block (i.e. a function in the
 107      case of C) is the STATIC_BLOCK.  The superblock of the
 108      STATIC_BLOCK is the GLOBAL_BLOCK.  */
 109
 110   const struct block *superblock;
 111
 112   /* This is used to store the symbols in the block.  */
 113
 114   struct multidictionary *multidict;
 115
 116   /* Contains information about namespace-related info relevant to this block:
 117      using directives and the current namespace scope.  */
 118
 119   struct block_namespace_info *namespace_info;
 120
 121   /* Address ranges for blocks with non-contiguous ranges.  If this
 122      is NULL, then there is only one range which is specified by
 123      startaddr and endaddr above.  */
 124
 125   struct blockranges *ranges;
 126 };
 127
 128 /* The global block is singled out so that we can provide a back-link
 129    to the compunit symtab.  */
 130
 131 struct global_block
 132 {
 133   /* The block.  */
 134
 135   struct block block;
 136
 137   /* This holds a pointer to the compunit symtab holding this block.  */
 138
 139   struct compunit_symtab *compunit_symtab;
 140 };
 141
 142 #define BLOCK_START(bl)         (bl)->startaddr
 143 #define BLOCK_END(bl)           (bl)->endaddr
 144 #define BLOCK_FUNCTION(bl)      (bl)->function
 145 #define BLOCK_SUPERBLOCK(bl)    (bl)->superblock
 146 #define BLOCK_MULTIDICT(bl)     (bl)->multidict
 147 #define BLOCK_NAMESPACE(bl)     (bl)->namespace_info
 148
 149 /* Accessor for ranges field within block BL.  */
 150
 151 #define BLOCK_RANGES(bl)        (bl)->ranges
 152
 153 /* Number of ranges within a block.  */
 154
 155 #define BLOCK_NRANGES(bl)       (bl)->ranges->nranges
 156
 157 /* Access range array for block BL.  */
 158
 159 #define BLOCK_RANGE(bl)         (bl)->ranges->range
 160
 161 /* Are all addresses within a block contiguous?  */
 162
 163 #define BLOCK_CONTIGUOUS_P(bl)  (BLOCK_RANGES (bl) == nullptr \
 164                                  || BLOCK_NRANGES (bl) <= 1)
 165
 166 /* Obtain the start address of the Nth range for block BL.  */
 167
 168 #define BLOCK_RANGE_START(bl,n) (BLOCK_RANGE (bl)[n].startaddr)
 169
 170 /* Obtain the end address of the Nth range for block BL.  */
 171
 172 #define BLOCK_RANGE_END(bl,n)   (BLOCK_RANGE (bl)[n].endaddr)
 173
 174 /* Define the "entry pc" for a block BL to be the lowest (start) address
 175    for the block when all addresses within the block are contiguous.  If
 176    non-contiguous, then use the start address for the first range in the
 177    block.
 178
 179    At the moment, this almost matches what DWARF specifies as the entry
 180    pc.  (The missing bit is support for DW_AT_entry_pc which should be
 181    preferred over range data and the low_pc.)
 182
 183    Once support for DW_AT_entry_pc is added, I expect that an entry_pc
 184    field will be added to one of these data structures.  Once that's done,
 185    the entry_pc field can be set from the dwarf reader (and other readers
 186    too).  BLOCK_ENTRY_PC can then be redefined to be less DWARF-centric.  */
 187
 188 #define BLOCK_ENTRY_PC(bl)      (BLOCK_CONTIGUOUS_P (bl) \
 189                                  ? BLOCK_START (bl) \
 190                                  : BLOCK_RANGE_START (bl,0))
 191
 192 struct blockvector
 193 {
 194   /* Number of blocks in the list.  */
 195   int nblocks;
 196   /* An address map mapping addresses to blocks in this blockvector.
 197      This pointer is zero if the blocks' start and end addresses are
 198      enough.  */
 199   struct addrmap *map;
 200   /* The blocks themselves.  */
 201   struct block *block[1];
 202 };
 203
 204 #define BLOCKVECTOR_NBLOCKS(blocklist) (blocklist)->nblocks
 205 #define BLOCKVECTOR_BLOCK(blocklist,n) (blocklist)->block[n]
 206 #define BLOCKVECTOR_MAP(blocklist) ((blocklist)->map)
 207
 208 /* Return the objfile of BLOCK, which must be non-NULL.  */
 209
 210 extern struct objfile *block_objfile (const struct block *block);
 211
 212 /* Return the architecture of BLOCK, which must be non-NULL.  */
 213
 214 extern struct gdbarch *block_gdbarch (const struct block *block);
 215
 216 extern struct symbol *block_linkage_function (const struct block *);
 217
 218 extern struct symbol *block_containing_function (const struct block *);
 219
 220 extern int block_inlined_p (const struct block *block);
 221
 222 /* Return true if block A is lexically nested within block B, or if a
 223    and b have the same pc range.  Return false otherwise.  If
 224    ALLOW_NESTED is true, then block A is considered to be in block B
 225    if A is in a nested function in B's function.  If ALLOW_NESTED is
 226    false (the default), then blocks in nested functions are not
 227    considered to be contained.  */
 228
 229 extern bool contained_in (const struct block *a, const struct block *b,
 230                           bool allow_nested = false);
 231
 232 extern const struct blockvector *blockvector_for_pc (CORE_ADDR,
 233                                                const struct block **);
 234
 235 extern const struct blockvector *
 236   blockvector_for_pc_sect (CORE_ADDR, struct obj_section *,
 237                            const struct block **, struct compunit_symtab *);
 238
 239 extern int blockvector_contains_pc (const struct blockvector *bv, CORE_ADDR pc);
 240
 241 extern struct call_site *call_site_for_pc (struct gdbarch *gdbarch,
 242                                            CORE_ADDR pc);
 243
 244 extern const struct block *block_for_pc (CORE_ADDR);
 245
 246 extern const struct block *block_for_pc_sect (CORE_ADDR, struct obj_section *);
 247
 248 extern const char *block_scope (const struct block *block);
 249
 250 extern void block_set_scope (struct block *block, const char *scope,
 251                              struct obstack *obstack);
 252
 253 extern struct using_direct *block_using (const struct block *block);
 254
 255 extern void block_set_using (struct block *block,
 256                              struct using_direct *using_decl,
 257                              struct obstack *obstack);
 258
 259 extern const struct block *block_static_block (const struct block *block);
 260
 261 extern const struct block *block_global_block (const struct block *block);
 262
 263 extern struct block *allocate_block (struct obstack *obstack);
 264
 265 extern struct block *allocate_global_block (struct obstack *obstack);
 266
 267 extern void set_block_compunit_symtab (struct block *,
 268                                        struct compunit_symtab *);
 269
 270 /* Return a property to evaluate the static link associated to BLOCK.
 271
 272    In the context of nested functions (available in Pascal, Ada and GNU C, for
 273    instance), a static link (as in DWARF's DW_AT_static_link attribute) for a
 274    function is a way to get the frame corresponding to the enclosing function.
 275
 276    Note that only objfile-owned and function-level blocks can have a static
 277    link.  Return NULL if there is no such property.  */
 278
 279 extern struct dynamic_prop *block_static_link (const struct block *block);
 280
 281 /* A block iterator.  This structure should be treated as though it
 282    were opaque; it is only defined here because we want to support
 283    stack allocation of iterators.  */
 284
 285 struct block_iterator
 286 {
 287   /* If we're iterating over a single block, this holds the block.
 288      Otherwise, it holds the canonical compunit.  */
 289
 290   union
 291   {
 292     struct compunit_symtab *compunit_symtab;
 293     const struct block *block;
 294   } d;
 295
 296   /* If we're iterating over a single block, this is always -1.
 297      Otherwise, it holds the index of the current "included" symtab in
 298      the canonical symtab (that is, d.symtab->includes[idx]), with -1
 299      meaning the canonical symtab itself.  */
 300
 301   int idx;
 302
 303   /* Which block, either static or global, to iterate over.  If this
 304      is FIRST_LOCAL_BLOCK, then we are iterating over a single block.
 305      This is used to select which field of 'd' is in use.  */
 306
 307   enum block_enum which;
 308
 309   /* The underlying multidictionary iterator.  */
 310
 311   struct mdict_iterator mdict_iter;
 312 };
 313
 314 /* Initialize ITERATOR to point at the first symbol in BLOCK, and
 315    return that first symbol, or NULL if BLOCK is empty.  */
 316
 317 extern struct symbol *block_iterator_first (const struct block *block,
 318                                             struct block_iterator *iterator);
 319
 320 /* Advance ITERATOR, and return the next symbol, or NULL if there are
 321    no more symbols.  Don't call this if you've previously received
 322    NULL from block_iterator_first or block_iterator_next on this
 323    iteration.  */
 324
 325 extern struct symbol *block_iterator_next (struct block_iterator *iterator);
 326
 327 /* Initialize ITERATOR to point at the first symbol in BLOCK whose
 328    search_name () matches NAME, and return that first symbol, or
 329    NULL if there are no such symbols.  */
 330
 331 extern struct symbol *block_iter_match_first (const struct block *block,
 332                                               const lookup_name_info &name,
 333                                               struct block_iterator *iterator);
 334
 335 /* Advance ITERATOR to point at the next symbol in BLOCK whose
 336    search_name () matches NAME, or NULL if there are no more such
 337    symbols.  Don't call this if you've previously received NULL from
 338    block_iterator_match_first or block_iterator_match_next on this
 339    iteration.  And don't call it unless ITERATOR was created by a
 340    previous call to block_iter_match_first with the same NAME.  */
 341
 342 extern struct symbol *block_iter_match_next
 343   (const lookup_name_info &name, struct block_iterator *iterator);
 344
 345 /* Return true if symbol A is the best match possible for DOMAIN.  */
 346
 347 extern bool best_symbol (struct symbol *a, const domain_enum domain);
 348
 349 /* Return symbol B if it is a better match than symbol A for DOMAIN.
 350    Otherwise return A.  */
 351
 352 extern struct symbol *better_symbol (struct symbol *a, struct symbol *b,
 353                                      const domain_enum domain);
 354
 355 /* Search BLOCK for symbol NAME in DOMAIN.  */
 356
 357 extern struct symbol *block_lookup_symbol (const struct block *block,
 358                                            const char *name,
 359                                            symbol_name_match_type match_type,
 360                                            const domain_enum domain);
 361
 362 /* Search BLOCK for symbol NAME in DOMAIN but only in primary symbol table of
 363    BLOCK.  BLOCK must be STATIC_BLOCK or GLOBAL_BLOCK.  Function is useful if
 364    one iterates all global/static blocks of an objfile.  */
 365
 366 extern struct symbol *block_lookup_symbol_primary (const struct block *block,
 367                                                    const char *name,
 368                                                    const domain_enum domain);
 369
 370 /* The type of the MATCHER argument to block_find_symbol.  */
 371
 372 typedef int (block_symbol_matcher_ftype) (struct symbol *, void *);
 373
 374 /* Find symbol NAME in BLOCK and in DOMAIN that satisfies MATCHER.
 375    DATA is passed unchanged to MATCHER.
 376    BLOCK must be STATIC_BLOCK or GLOBAL_BLOCK.  */
 377
 378 extern struct symbol *block_find_symbol (const struct block *block,
 379                                          const char *name,
 380                                          const domain_enum domain,
 381                                          block_symbol_matcher_ftype *matcher,
 382                                          void *data);
 383
 384 /* A matcher function for block_find_symbol to find only symbols with
 385    non-opaque types.  */
 386
 387 extern int block_find_non_opaque_type (struct symbol *sym, void *data);
 388
 389 /* A matcher function for block_find_symbol to prefer symbols with
 390    non-opaque types.  The way to use this function is as follows:
 391
 392    struct symbol *with_opaque = NULL;
 393    struct symbol *sym
 394      = block_find_symbol (block, name, domain,
 395                           block_find_non_opaque_type_preferred, &with_opaque);
 396
 397    At this point if SYM is non-NULL then a non-opaque type has been found.
 398    Otherwise, if WITH_OPAQUE is non-NULL then an opaque type has been found.
 399    Otherwise, the symbol was not found.  */
 400
 401 extern int block_find_non_opaque_type_preferred (struct symbol *sym,
 402                                                  void *data);
 403
 404 /* Macro to loop through all symbols in BLOCK, in no particular
 405    order.  ITER helps keep track of the iteration, and must be a
 406    struct block_iterator.  SYM points to the current symbol.  */
 407
 408 #define ALL_BLOCK_SYMBOLS(block, iter, sym)             \
 409   for ((sym) = block_iterator_first ((block), &(iter)); \
 410        (sym);                                           \
 411        (sym) = block_iterator_next (&(iter)))
 412
 413 /* Macro to loop through all symbols in BLOCK with a name that matches
 414    NAME, in no particular order.  ITER helps keep track of the
 415    iteration, and must be a struct block_iterator.  SYM points to the
 416    current symbol.  */
 417
 418 #define ALL_BLOCK_SYMBOLS_WITH_NAME(block, name, iter, sym)             \
 419   for ((sym) = block_iter_match_first ((block), (name), &(iter));       \
 420        (sym) != NULL;                                                   \
 421        (sym) = block_iter_match_next ((name), &(iter)))
 422
 423 /* Given a vector of pairs, allocate and build an obstack allocated
 424    blockranges struct for a block.  */
 425 struct blockranges *make_blockranges (struct objfile *objfile,
 426                                       const std::vector<blockrange> &rangevec);
 427
 428 #endif /* BLOCK_H */