gdb/block.h

   1 /* Code dealing with blocks for GDB.
   2
   3    Copyright (C) 2003-2019 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 extern int contained_in (const struct block *, const struct block *);
 223
 224 extern const struct blockvector *blockvector_for_pc (CORE_ADDR,
 225                                                const struct block **);
 226
 227 extern const struct blockvector *
 228   blockvector_for_pc_sect (CORE_ADDR, struct obj_section *,
 229                            const struct block **, struct compunit_symtab *);
 230
 231 extern int blockvector_contains_pc (const struct blockvector *bv, CORE_ADDR pc);
 232
 233 extern struct call_site *call_site_for_pc (struct gdbarch *gdbarch,
 234                                            CORE_ADDR pc);
 235
 236 extern const struct block *block_for_pc (CORE_ADDR);
 237
 238 extern const struct block *block_for_pc_sect (CORE_ADDR, struct obj_section *);
 239
 240 extern const char *block_scope (const struct block *block);
 241
 242 extern void block_set_scope (struct block *block, const char *scope,
 243                              struct obstack *obstack);
 244
 245 extern struct using_direct *block_using (const struct block *block);
 246
 247 extern void block_set_using (struct block *block,
 248                              struct using_direct *using_decl,
 249                              struct obstack *obstack);
 250
 251 extern const struct block *block_static_block (const struct block *block);
 252
 253 extern const struct block *block_global_block (const struct block *block);
 254
 255 extern struct block *allocate_block (struct obstack *obstack);
 256
 257 extern struct block *allocate_global_block (struct obstack *obstack);
 258
 259 extern void set_block_compunit_symtab (struct block *,
 260                                        struct compunit_symtab *);
 261
 262 /* Return a property to evaluate the static link associated to BLOCK.
 263
 264    In the context of nested functions (available in Pascal, Ada and GNU C, for
 265    instance), a static link (as in DWARF's DW_AT_static_link attribute) for a
 266    function is a way to get the frame corresponding to the enclosing function.
 267
 268    Note that only objfile-owned and function-level blocks can have a static
 269    link.  Return NULL if there is no such property.  */
 270
 271 extern struct dynamic_prop *block_static_link (const struct block *block);
 272
 273 /* A block iterator.  This structure should be treated as though it
 274    were opaque; it is only defined here because we want to support
 275    stack allocation of iterators.  */
 276
 277 struct block_iterator
 278 {
 279   /* If we're iterating over a single block, this holds the block.
 280      Otherwise, it holds the canonical compunit.  */
 281
 282   union
 283   {
 284     struct compunit_symtab *compunit_symtab;
 285     const struct block *block;
 286   } d;
 287
 288   /* If we're iterating over a single block, this is always -1.
 289      Otherwise, it holds the index of the current "included" symtab in
 290      the canonical symtab (that is, d.symtab->includes[idx]), with -1
 291      meaning the canonical symtab itself.  */
 292
 293   int idx;
 294
 295   /* Which block, either static or global, to iterate over.  If this
 296      is FIRST_LOCAL_BLOCK, then we are iterating over a single block.
 297      This is used to select which field of 'd' is in use.  */
 298
 299   enum block_enum which;
 300
 301   /* The underlying multidictionary iterator.  */
 302
 303   struct mdict_iterator mdict_iter;
 304 };
 305
 306 /* Initialize ITERATOR to point at the first symbol in BLOCK, and
 307    return that first symbol, or NULL if BLOCK is empty.  */
 308
 309 extern struct symbol *block_iterator_first (const struct block *block,
 310                                             struct block_iterator *iterator);
 311
 312 /* Advance ITERATOR, and return the next symbol, or NULL if there are
 313    no more symbols.  Don't call this if you've previously received
 314    NULL from block_iterator_first or block_iterator_next on this
 315    iteration.  */
 316
 317 extern struct symbol *block_iterator_next (struct block_iterator *iterator);
 318
 319 /* Initialize ITERATOR to point at the first symbol in BLOCK whose
 320    SYMBOL_SEARCH_NAME matches NAME, and return that first symbol, or
 321    NULL if there are no such symbols.  */
 322
 323 extern struct symbol *block_iter_match_first (const struct block *block,
 324                                               const lookup_name_info &name,
 325                                               struct block_iterator *iterator);
 326
 327 /* Advance ITERATOR to point at the next symbol in BLOCK whose
 328    SYMBOL_SEARCH_NAME matches NAME, or NULL if there are no more such
 329    symbols.  Don't call this if you've previously received NULL from
 330    block_iterator_match_first or block_iterator_match_next on this
 331    iteration.  And don't call it unless ITERATOR was created by a
 332    previous call to block_iter_match_first with the same NAME.  */
 333
 334 extern struct symbol *block_iter_match_next
 335   (const lookup_name_info &name, struct block_iterator *iterator);
 336
 337 /* Search BLOCK for symbol NAME in DOMAIN.  */
 338
 339 extern struct symbol *block_lookup_symbol (const struct block *block,
 340                                            const char *name,
 341                                            symbol_name_match_type match_type,
 342                                            const domain_enum domain);
 343
 344 /* Search BLOCK for symbol NAME in DOMAIN but only in primary symbol table of
 345    BLOCK.  BLOCK must be STATIC_BLOCK or GLOBAL_BLOCK.  Function is useful if
 346    one iterates all global/static blocks of an objfile.  */
 347
 348 extern struct symbol *block_lookup_symbol_primary (const struct block *block,
 349                                                    const char *name,
 350                                                    const domain_enum domain);
 351
 352 /* The type of the MATCHER argument to block_find_symbol.  */
 353
 354 typedef int (block_symbol_matcher_ftype) (struct symbol *, void *);
 355
 356 /* Find symbol NAME in BLOCK and in DOMAIN that satisfies MATCHER.
 357    DATA is passed unchanged to MATCHER.
 358    BLOCK must be STATIC_BLOCK or GLOBAL_BLOCK.  */
 359
 360 extern struct symbol *block_find_symbol (const struct block *block,
 361                                          const char *name,
 362                                          const domain_enum domain,
 363                                          block_symbol_matcher_ftype *matcher,
 364                                          void *data);
 365
 366 /* A matcher function for block_find_symbol to find only symbols with
 367    non-opaque types.  */
 368
 369 extern int block_find_non_opaque_type (struct symbol *sym, void *data);
 370
 371 /* A matcher function for block_find_symbol to prefer symbols with
 372    non-opaque types.  The way to use this function is as follows:
 373
 374    struct symbol *with_opaque = NULL;
 375    struct symbol *sym
 376      = block_find_symbol (block, name, domain,
 377                           block_find_non_opaque_type_preferred, &with_opaque);
 378
 379    At this point if SYM is non-NULL then a non-opaque type has been found.
 380    Otherwise, if WITH_OPAQUE is non-NULL then an opaque type has been found.
 381    Otherwise, the symbol was not found.  */
 382
 383 extern int block_find_non_opaque_type_preferred (struct symbol *sym,
 384                                                  void *data);
 385
 386 /* Macro to loop through all symbols in BLOCK, in no particular
 387    order.  ITER helps keep track of the iteration, and must be a
 388    struct block_iterator.  SYM points to the current symbol.  */
 389
 390 #define ALL_BLOCK_SYMBOLS(block, iter, sym)             \
 391   for ((sym) = block_iterator_first ((block), &(iter)); \
 392        (sym);                                           \
 393        (sym) = block_iterator_next (&(iter)))
 394
 395 /* Macro to loop through all symbols in BLOCK with a name that matches
 396    NAME, in no particular order.  ITER helps keep track of the
 397    iteration, and must be a struct block_iterator.  SYM points to the
 398    current symbol.  */
 399
 400 #define ALL_BLOCK_SYMBOLS_WITH_NAME(block, name, iter, sym)             \
 401   for ((sym) = block_iter_match_first ((block), (name), &(iter));       \
 402        (sym) != NULL;                                                   \
 403        (sym) = block_iter_match_next ((name), &(iter)))
 404
 405 /* Given a vector of pairs, allocate and build an obstack allocated
 406    blockranges struct for a block.  */
 407 struct blockranges *make_blockranges (struct objfile *objfile,
 408                                       const std::vector<blockrange> &rangevec);
 409
 410 #endif /* BLOCK_H */