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
27struct symbol;
28struct compunit_symtab;
29struct block_namespace_info;
30struct using_direct;
31struct obstack;
32struct 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
39struct 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
59struct 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
91struct 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
131struct 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
192struct 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
210extern struct objfile *block_objfile (const struct block *block);
211
212/* Return the architecture of BLOCK, which must be non-NULL.  */
213
214extern struct gdbarch *block_gdbarch (const struct block *block);
215
216extern struct symbol *block_linkage_function (const struct block *);
217
218extern struct symbol *block_containing_function (const struct block *);
219
220extern 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
229extern bool contained_in (const struct block *a, const struct block *b,
230			  bool allow_nested = false);
231
232extern const struct blockvector *blockvector_for_pc (CORE_ADDR,
233					       const struct block **);
234
235extern const struct blockvector *
236  blockvector_for_pc_sect (CORE_ADDR, struct obj_section *,
237			   const struct block **, struct compunit_symtab *);
238
239extern int blockvector_contains_pc (const struct blockvector *bv, CORE_ADDR pc);
240
241extern struct call_site *call_site_for_pc (struct gdbarch *gdbarch,
242					   CORE_ADDR pc);
243
244extern const struct block *block_for_pc (CORE_ADDR);
245
246extern const struct block *block_for_pc_sect (CORE_ADDR, struct obj_section *);
247
248extern const char *block_scope (const struct block *block);
249
250extern void block_set_scope (struct block *block, const char *scope,
251			     struct obstack *obstack);
252
253extern struct using_direct *block_using (const struct block *block);
254
255extern void block_set_using (struct block *block,
256			     struct using_direct *using_decl,
257			     struct obstack *obstack);
258
259extern const struct block *block_static_block (const struct block *block);
260
261extern const struct block *block_global_block (const struct block *block);
262
263extern struct block *allocate_block (struct obstack *obstack);
264
265extern struct block *allocate_global_block (struct obstack *obstack);
266
267extern 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
279extern 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
285struct 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
317extern 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
325extern 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
331extern 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
342extern 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
347extern 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
352extern 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
357extern 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
366extern 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
372typedef 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
378extern 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
387extern 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
401extern 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.  */
425struct blockranges *make_blockranges (struct objfile *objfile,
426                                      const std::vector<blockrange> &rangevec);
427
428#endif /* BLOCK_H */
429