1/* A type-safe hash table template.
2 Copyright (C) 2012-2025 Free Software Foundation, Inc.
3 Contributed by Lawrence Crowl <crowl@google.com>
4
5This file is part of GCC.
6
7GCC is free software; you can redistribute it and/or modify it under
8the terms of the GNU General Public License as published by the Free
9Software Foundation; either version 3, or (at your option) any later
10version.
11
12GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13WARRANTY; without even the implied warranty of MERCHANTABILITY or
14FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
15for more details.
16
17You should have received a copy of the GNU General Public License
18along with GCC; see the file COPYING3. If not see
19<http://www.gnu.org/licenses/>. */
20
21
22/* This file implements a typed hash table.
23 The implementation borrows from libiberty's htab_t in hashtab.h.
24
25
26 INTRODUCTION TO TYPES
27
28 Users of the hash table generally need to be aware of three types.
29
30 1. The type being placed into the hash table. This type is called
31 the value type.
32
33 2. The type used to describe how to handle the value type within
34 the hash table. This descriptor type provides the hash table with
35 several things.
36
37 - A typedef named 'value_type' to the value type (from above).
38 Provided a suitable Descriptor class it may be a user-defined,
39 non-POD type.
40
41 - A static member function named 'hash' that takes a value_type
42 (or 'const value_type &') and returns a hashval_t value.
43
44 - A typedef named 'compare_type' that is used to test when a value
45 is found. This type is the comparison type. Usually, it will be
46 the same as value_type and may be a user-defined, non-POD type.
47 If it is not the same type, you must generally explicitly compute
48 hash values and pass them to the hash table.
49
50 - A static member function named 'equal' that takes a value_type
51 and a compare_type, and returns a bool. Both arguments can be
52 const references.
53
54 - A static function named 'remove' that takes an value_type pointer
55 and frees the memory allocated by it. This function is used when
56 individual elements of the table need to be disposed of (e.g.,
57 when deleting a hash table, removing elements from the table, etc).
58
59 - An optional static function named 'keep_cache_entry'. This
60 function is provided only for garbage-collected elements that
61 are not marked by the normal gc mark pass. It describes what
62 what should happen to the element at the end of the gc mark phase.
63 The return value should be:
64 - 0 if the element should be deleted
65 - 1 if the element should be kept and needs to be marked
66 - -1 if the element should be kept and is already marked.
67 Returning -1 rather than 1 is purely an optimization.
68
69 3. The type of the hash table itself. (More later.)
70
71 In very special circumstances, users may need to know about a fourth type.
72
73 4. The template type used to describe how hash table memory
74 is allocated. This type is called the allocator type. It is
75 parameterized on the value type. It provides two functions:
76
77 - A static member function named 'data_alloc'. This function
78 allocates the data elements in the table.
79
80 - A static member function named 'data_free'. This function
81 deallocates the data elements in the table.
82
83 Hash table are instantiated with two type arguments.
84
85 * The descriptor type, (2) above.
86
87 * The allocator type, (4) above. In general, you will not need to
88 provide your own allocator type. By default, hash tables will use
89 the class template xcallocator, which uses malloc/free for allocation.
90
91
92 DEFINING A DESCRIPTOR TYPE
93
94 The first task in using the hash table is to describe the element type.
95 We compose this into a few steps.
96
97 1. Decide on a removal policy for values stored in the table.
98 hash-traits.h provides class templates for the four most common
99 policies:
100
101 * typed_free_remove implements the static 'remove' member function
102 by calling free().
103
104 * typed_noop_remove implements the static 'remove' member function
105 by doing nothing.
106
107 * ggc_remove implements the static 'remove' member by doing nothing,
108 but instead provides routines for gc marking and for PCH streaming.
109 Use this for garbage-collected data that needs to be preserved across
110 collections.
111
112 * ggc_cache_remove is like ggc_remove, except that it does not
113 mark the entries during the normal gc mark phase. Instead it
114 uses 'keep_cache_entry' (described above) to keep elements that
115 were not collected and delete those that were. Use this for
116 garbage-collected caches that should not in themselves stop
117 the data from being collected.
118
119 You can use these policies by simply deriving the descriptor type
120 from one of those class template, with the appropriate argument.
121
122 Otherwise, you need to write the static 'remove' member function
123 in the descriptor class.
124
125 2. Choose a hash function. Write the static 'hash' member function.
126
127 3. Decide whether the lookup function should take as input an object
128 of type value_type or something more restricted. Define compare_type
129 accordingly.
130
131 4. Choose an equality testing function 'equal' that compares a value_type
132 and a compare_type.
133
134 If your elements are pointers, it is usually easiest to start with one
135 of the generic pointer descriptors described below and override the bits
136 you need to change.
137
138 AN EXAMPLE DESCRIPTOR TYPE
139
140 Suppose you want to put some_type into the hash table. You could define
141 the descriptor type as follows.
142
143 struct some_type_hasher : nofree_ptr_hash <some_type>
144 // Deriving from nofree_ptr_hash means that we get a 'remove' that does
145 // nothing. This choice is good for raw values.
146 {
147 static inline hashval_t hash (const value_type *);
148 static inline bool equal (const value_type *, const compare_type *);
149 };
150
151 inline hashval_t
152 some_type_hasher::hash (const value_type *e)
153 { ... compute and return a hash value for E ... }
154
155 inline bool
156 some_type_hasher::equal (const value_type *p1, const compare_type *p2)
157 { ... compare P1 vs P2. Return true if they are the 'same' ... }
158
159
160 AN EXAMPLE HASH_TABLE DECLARATION
161
162 To instantiate a hash table for some_type:
163
164 hash_table <some_type_hasher> some_type_hash_table;
165
166 There is no need to mention some_type directly, as the hash table will
167 obtain it using some_type_hasher::value_type.
168
169 You can then use any of the functions in hash_table's public interface.
170 See hash_table for details. The interface is very similar to libiberty's
171 htab_t.
172
173 If a hash table is used only in some rare cases, it is possible
174 to construct the hash_table lazily before first use. This is done
175 through:
176
177 hash_table <some_type_hasher, true> some_type_hash_table;
178
179 which will cause whatever methods actually need the allocated entries
180 array to allocate it later.
181
182
183 EASY DESCRIPTORS FOR POINTERS
184
185 There are four descriptors for pointer elements, one for each of
186 the removal policies above:
187
188 * nofree_ptr_hash (based on typed_noop_remove)
189 * free_ptr_hash (based on typed_free_remove)
190 * ggc_ptr_hash (based on ggc_remove)
191 * ggc_cache_ptr_hash (based on ggc_cache_remove)
192
193 These descriptors hash and compare elements by their pointer value,
194 rather than what they point to. So, to instantiate a hash table over
195 pointers to whatever_type, without freeing the whatever_types, use:
196
197 hash_table <nofree_ptr_hash <whatever_type> > whatever_type_hash_table;
198
199
200 HASH TABLE ITERATORS
201
202 The hash table provides standard C++ iterators. For example, consider a
203 hash table of some_info. We wish to consume each element of the table:
204
205 extern void consume (some_info *);
206
207 We define a convenience typedef and the hash table:
208
209 typedef hash_table <some_info_hasher> info_table_type;
210 info_table_type info_table;
211
212 Then we write the loop in typical C++ style:
213
214 for (info_table_type::iterator iter = info_table.begin ();
215 iter != info_table.end ();
216 ++iter)
217 if ((*iter).status == INFO_READY)
218 consume (&*iter);
219
220 Or with common sub-expression elimination:
221
222 for (info_table_type::iterator iter = info_table.begin ();
223 iter != info_table.end ();
224 ++iter)
225 {
226 some_info &elem = *iter;
227 if (elem.status == INFO_READY)
228 consume (&elem);
229 }
230
231 One can also use a more typical GCC style:
232
233 typedef some_info *some_info_p;
234 some_info *elem_ptr;
235 info_table_type::iterator iter;
236 FOR_EACH_HASH_TABLE_ELEMENT (info_table, elem_ptr, some_info_p, iter)
237 if (elem_ptr->status == INFO_READY)
238 consume (elem_ptr);
239
240*/
241
242
243#ifndef TYPED_HASHTAB_H
244#define TYPED_HASHTAB_H
245
246#include "statistics.h"
247#include "ggc.h"
248#include "vec.h"
249#include "hashtab.h"
250#include "inchash.h"
251#include "mem-stats-traits.h"
252#include "hash-traits.h"
253#include "hash-map-traits.h"
254
255template<typename, typename, typename> class hash_map;
256template<typename, bool, typename> class hash_set;
257
258/* The ordinary memory allocator. */
259/* FIXME (crowl): This allocator may be extracted for wider sharing later. */
260
261template <typename Type>
262struct xcallocator
263{
264 static Type *data_alloc (size_t count);
265 static void data_free (Type *memory);
266};
267
268
269/* Allocate memory for COUNT data blocks. */
270
271template <typename Type>
272inline Type *
273xcallocator <Type>::data_alloc (size_t count)
274{
275 return static_cast <Type *> (xcalloc (count, sizeof (Type)));
276}
277
278
279/* Free memory for data blocks. */
280
281template <typename Type>
282inline void
283xcallocator <Type>::data_free (Type *memory)
284{
285 return ::free (ptr: memory);
286}
287
288
289/* Table of primes and their inversion information. */
290
291struct prime_ent
292{
293 hashval_t prime;
294 hashval_t inv;
295 hashval_t inv_m2; /* inverse of prime-2 */
296 hashval_t shift;
297};
298
299extern struct prime_ent const prime_tab[];
300
301/* Limit number of comparisons when calling hash_table<>::verify. */
302extern unsigned int hash_table_sanitize_eq_limit;
303
304/* Functions for computing hash table indexes. */
305
306extern unsigned int hash_table_higher_prime_index (unsigned long n)
307 ATTRIBUTE_PURE;
308
309extern ATTRIBUTE_NORETURN ATTRIBUTE_COLD void hashtab_chk_error ();
310
311/* Return X % Y using multiplicative inverse values INV and SHIFT.
312
313 The multiplicative inverses computed above are for 32-bit types,
314 and requires that we be able to compute a highpart multiply.
315
316 FIX: I am not at all convinced that
317 3 loads, 2 multiplications, 3 shifts, and 3 additions
318 will be faster than
319 1 load and 1 modulus
320 on modern systems running a compiler. */
321
322inline hashval_t
323mul_mod (hashval_t x, hashval_t y, hashval_t inv, int shift)
324{
325 hashval_t t1, t2, t3, t4, q, r;
326
327 t1 = ((uint64_t)x * inv) >> 32;
328 t2 = x - t1;
329 t3 = t2 >> 1;
330 t4 = t1 + t3;
331 q = t4 >> shift;
332 r = x - (q * y);
333
334 return r;
335}
336
337/* Compute the primary table index for HASH given current prime index. */
338
339inline hashval_t
340hash_table_mod1 (hashval_t hash, unsigned int index)
341{
342 const struct prime_ent *p = &prime_tab[index];
343 gcc_checking_assert (sizeof (hashval_t) * CHAR_BIT <= 32);
344 return mul_mod (x: hash, y: p->prime, inv: p->inv, shift: p->shift);
345}
346
347/* Compute the secondary table index for HASH given current prime index. */
348
349inline hashval_t
350hash_table_mod2 (hashval_t hash, unsigned int index)
351{
352 const struct prime_ent *p = &prime_tab[index];
353 gcc_checking_assert (sizeof (hashval_t) * CHAR_BIT <= 32);
354 return 1 + mul_mod (x: hash, y: p->prime - 2, inv: p->inv_m2, shift: p->shift);
355}
356
357class mem_usage;
358
359/* User-facing hash table type.
360
361 The table stores elements of type Descriptor::value_type and uses
362 the static descriptor functions described at the top of the file
363 to hash, compare and remove elements.
364
365 Specify the template Allocator to allocate and free memory.
366 The default is xcallocator.
367
368 Storage is an implementation detail and should not be used outside the
369 hash table code.
370
371*/
372template <typename Descriptor, bool Lazy = false,
373 template<typename Type> class Allocator = xcallocator>
374class hash_table
375{
376 typedef typename Descriptor::value_type value_type;
377 typedef typename Descriptor::compare_type compare_type;
378
379public:
380 explicit hash_table (size_t, bool ggc = false,
381 bool sanitize_eq_and_hash = true,
382 bool gather_mem_stats = GATHER_STATISTICS,
383 mem_alloc_origin origin = HASH_TABLE_ORIGIN
384 CXX_MEM_STAT_INFO);
385 explicit hash_table (const hash_table &, bool ggc = false,
386 bool sanitize_eq_and_hash = true,
387 bool gather_mem_stats = GATHER_STATISTICS,
388 mem_alloc_origin origin = HASH_TABLE_ORIGIN
389 CXX_MEM_STAT_INFO);
390 ~hash_table ();
391
392 /* Create a hash_table in gc memory. */
393 static hash_table *
394 create_ggc (size_t n, bool sanitize_eq_and_hash = true CXX_MEM_STAT_INFO)
395 {
396 hash_table *table = ggc_alloc<hash_table> ();
397 new (table) hash_table (n, true, sanitize_eq_and_hash, GATHER_STATISTICS,
398 HASH_TABLE_ORIGIN PASS_MEM_STAT);
399 return table;
400 }
401
402 /* Current size (in entries) of the hash table. */
403 size_t size () const { return m_size; }
404
405 /* Return the current number of elements in this hash table. */
406 size_t elements () const { return m_n_elements - m_n_deleted; }
407
408 /* Return the current number of elements in this hash table. */
409 size_t elements_with_deleted () const { return m_n_elements; }
410
411 /* This function clears all entries in this hash table. */
412 void empty () { if (elements ()) empty_slow (); }
413
414 /* Return true when there are no elements in this hash table. */
415 bool is_empty () const { return elements () == 0; }
416
417 /* This function clears a specified SLOT in a hash table. It is
418 useful when you've already done the lookup and don't want to do it
419 again. */
420 void clear_slot (value_type *);
421
422 /* This function searches for a hash table entry equal to the given
423 COMPARABLE element starting with the given HASH value. It cannot
424 be used to insert or delete an element. */
425 value_type &find_with_hash (const compare_type &, hashval_t);
426
427 /* Like find_slot_with_hash, but compute the hash value from the element. */
428 value_type &find (const value_type &value)
429 {
430 return find_with_hash (value, Descriptor::hash (value));
431 }
432
433 value_type *find_slot (const value_type &value, insert_option insert)
434 {
435 return find_slot_with_hash (comparable: value, hash: Descriptor::hash (value), insert);
436 }
437
438 /* This function searches for a hash table slot containing an entry
439 equal to the given COMPARABLE element and starting with the given
440 HASH. To delete an entry, call this with insert=NO_INSERT, then
441 call clear_slot on the slot returned (possibly after doing some
442 checks). To insert an entry, call this with insert=INSERT, then
443 write the value you want into the returned slot. When inserting an
444 entry, NULL may be returned if memory allocation fails. */
445 value_type *find_slot_with_hash (const compare_type &comparable,
446 hashval_t hash, enum insert_option insert);
447
448 /* This function deletes an element with the given COMPARABLE value
449 from hash table starting with the given HASH. If there is no
450 matching element in the hash table, this function does nothing. */
451 void remove_elt_with_hash (const compare_type &, hashval_t);
452
453 /* Like remove_elt_with_hash, but compute the hash value from the
454 element. */
455 void remove_elt (const value_type &value)
456 {
457 remove_elt_with_hash (value, Descriptor::hash (value));
458 }
459
460 /* This function scans over the entire hash table calling CALLBACK for
461 each live entry. If CALLBACK returns false, the iteration stops.
462 ARGUMENT is passed as CALLBACK's second argument. */
463 template <typename Argument,
464 int (*Callback) (value_type *slot, Argument argument)>
465 void traverse_noresize (Argument argument);
466
467 /* Like traverse_noresize, but does resize the table when it is too empty
468 to improve effectivity of subsequent calls. */
469 template <typename Argument,
470 int (*Callback) (value_type *slot, Argument argument)>
471 void traverse (Argument argument);
472
473 class iterator
474 {
475 public:
476 iterator () : m_slot (NULL), m_limit (NULL) {}
477
478 iterator (value_type *slot, value_type *limit) :
479 m_slot (slot), m_limit (limit) {}
480
481 inline value_type &operator * () { return *m_slot; }
482 void slide ();
483 inline iterator &operator ++ ();
484 bool operator != (const iterator &other) const
485 {
486 return m_slot != other.m_slot || m_limit != other.m_limit;
487 }
488
489 private:
490 value_type *m_slot;
491 value_type *m_limit;
492 };
493
494 iterator begin () const
495 {
496 if (Lazy && m_entries == NULL)
497 return iterator ();
498 check_complete_insertion ();
499 iterator iter (m_entries, m_entries + m_size);
500 iter.slide ();
501 return iter;
502 }
503
504 iterator end () const { return iterator (); }
505
506 double collisions () const
507 {
508 return m_searches ? static_cast <double> (m_collisions) / m_searches : 0;
509 }
510
511private:
512 /* FIXME: Make the class assignable. See pr90959. */
513 void operator= (hash_table&);
514
515 template<typename T> friend void gt_ggc_mx (hash_table<T> *);
516 template<typename T> friend void gt_pch_nx (hash_table<T> *);
517 template<typename T> friend void
518 hashtab_entry_note_pointers (void *, void *, gt_pointer_operator, void *);
519 template<typename T, typename U, typename V> friend void
520 gt_pch_nx (hash_map<T, U, V> *, gt_pointer_operator, void *);
521 template<typename T, typename U>
522 friend void gt_pch_nx (hash_set<T, false, U> *, gt_pointer_operator, void *);
523 template<typename T> friend void gt_pch_nx (hash_table<T> *,
524 gt_pointer_operator, void *);
525
526 template<typename T> friend void gt_cleare_cache (hash_table<T> *);
527
528 void empty_slow ();
529
530 value_type *alloc_entries (size_t n CXX_MEM_STAT_INFO) const;
531 value_type *find_empty_slot_for_expand (hashval_t);
532 void verify (const compare_type &comparable, hashval_t hash);
533 bool too_empty_p (unsigned int);
534 void expand ();
535 static bool is_deleted (value_type &v)
536 {
537 /* Traits are supposed to avoid recognizing elements as both empty
538 and deleted, but to fail safe in case custom traits fail to do
539 that, make sure we never test for is_deleted without having
540 first ruled out is_empty. */
541 gcc_checking_assert (!Descriptor::is_empty (v));
542 return Descriptor::is_deleted (v);
543 }
544
545 static bool is_empty (value_type &v)
546 {
547 return Descriptor::is_empty (v);
548 }
549
550 static void mark_deleted (value_type &v)
551 {
552 Descriptor::mark_deleted (v);
553 /* Traits are supposed to refuse to set elements as deleted if
554 those would be indistinguishable from empty, but to fail safe
555 in case custom traits fail to do that, check that the
556 just-deleted element does not look empty. */
557 gcc_checking_assert (!Descriptor::is_empty (v));
558 }
559
560 static void mark_empty (value_type &v)
561 {
562 Descriptor::mark_empty (v);
563 }
564
565public:
566 void check_complete_insertion () const
567 {
568#if CHECKING_P
569 if (!m_inserting_slot)
570 return;
571
572 gcc_checking_assert (m_inserting_slot >= &m_entries[0]
573 && m_inserting_slot < &m_entries[m_size]);
574
575 if (!is_empty (*m_inserting_slot))
576 m_inserting_slot = NULL;
577 else
578 gcc_unreachable ();
579#endif
580 }
581
582private:
583 value_type *check_insert_slot (value_type *ret)
584 {
585#if CHECKING_P
586 gcc_checking_assert (is_empty (*ret));
587 m_inserting_slot = ret;
588#endif
589 return ret;
590 }
591
592#if CHECKING_P
593 mutable value_type *m_inserting_slot;
594#endif
595
596 /* Table itself. */
597 value_type *m_entries;
598
599 size_t m_size;
600
601 /* Current number of elements including also deleted elements. */
602 size_t m_n_elements;
603
604 /* Current number of deleted elements in the table. */
605 size_t m_n_deleted;
606
607 /* The following member is used for debugging. Its value is number
608 of all calls of `htab_find_slot' for the hash table. */
609 unsigned int m_searches;
610
611 /* The following member is used for debugging. Its value is number
612 of collisions fixed for time of work with the hash table. */
613 unsigned int m_collisions;
614
615 /* Current size (in entries) of the hash table, as an index into the
616 table of primes. */
617 unsigned int m_size_prime_index;
618
619 /* if m_entries is stored in ggc memory. */
620 bool m_ggc;
621
622 /* True if the table should be sanitized for equal and hash functions. */
623 bool m_sanitize_eq_and_hash;
624
625 /* If we should gather memory statistics for the table. */
626#if GATHER_STATISTICS
627 bool m_gather_mem_stats;
628#else
629 static const bool m_gather_mem_stats = false;
630#endif
631};
632
633/* As mem-stats.h heavily utilizes hash maps (hash tables), we have to include
634 mem-stats.h after hash_table declaration. */
635
636#include "mem-stats.h"
637#include "hash-map.h"
638
639extern mem_alloc_description<mem_usage>& hash_table_usage (void);
640
641/* Support function for statistics. */
642extern void dump_hash_table_loc_statistics (void);
643
644template<typename Descriptor, bool Lazy,
645 template<typename Type> class Allocator>
646hash_table<Descriptor, Lazy, Allocator>::hash_table (size_t size, bool ggc,
647 bool sanitize_eq_and_hash,
648 bool gather_mem_stats
649 ATTRIBUTE_UNUSED,
650 mem_alloc_origin origin
651 MEM_STAT_DECL) :
652#if CHECKING_P
653 m_inserting_slot (0),
654#endif
655 m_n_elements (0), m_n_deleted (0), m_searches (0), m_collisions (0),
656 m_ggc (ggc), m_sanitize_eq_and_hash (sanitize_eq_and_hash)
657#if GATHER_STATISTICS
658 , m_gather_mem_stats (gather_mem_stats)
659#endif
660{
661 unsigned int size_prime_index;
662
663 size_prime_index = hash_table_higher_prime_index (n: size);
664 size = prime_tab[size_prime_index].prime;
665
666 if (m_gather_mem_stats)
667 hash_table_usage ().register_descriptor (this, origin, ggc
668 FINAL_PASS_MEM_STAT);
669
670 if (Lazy)
671 m_entries = NULL;
672 else
673 m_entries = alloc_entries (n: size PASS_MEM_STAT);
674 m_size = size;
675 m_size_prime_index = size_prime_index;
676}
677
678template<typename Descriptor, bool Lazy,
679 template<typename Type> class Allocator>
680hash_table<Descriptor, Lazy, Allocator>::hash_table (const hash_table &h,
681 bool ggc,
682 bool sanitize_eq_and_hash,
683 bool gather_mem_stats
684 ATTRIBUTE_UNUSED,
685 mem_alloc_origin origin
686 MEM_STAT_DECL) :
687#if CHECKING_P
688 m_inserting_slot (0),
689#endif
690 m_n_elements (h.m_n_elements), m_n_deleted (h.m_n_deleted),
691 m_searches (0), m_collisions (0), m_ggc (ggc),
692 m_sanitize_eq_and_hash (sanitize_eq_and_hash)
693#if GATHER_STATISTICS
694 , m_gather_mem_stats (gather_mem_stats)
695#endif
696{
697 h.check_complete_insertion ();
698
699 size_t size = h.m_size;
700
701 if (m_gather_mem_stats)
702 hash_table_usage ().register_descriptor (this, origin, ggc
703 FINAL_PASS_MEM_STAT);
704
705 if (Lazy && h.m_entries == NULL)
706 m_entries = NULL;
707 else
708 {
709 value_type *nentries = alloc_entries (n: size PASS_MEM_STAT);
710 for (size_t i = 0; i < size; ++i)
711 {
712 value_type &entry = h.m_entries[i];
713 if (is_empty (entry))
714 continue;
715 else if (is_deleted (v&: entry))
716 mark_deleted (v&: nentries[i]);
717 else
718 new ((void*) (nentries + i)) value_type (entry);
719 }
720 m_entries = nentries;
721 }
722 m_size = size;
723 m_size_prime_index = h.m_size_prime_index;
724}
725
726template<typename Descriptor, bool Lazy,
727 template<typename Type> class Allocator>
728hash_table<Descriptor, Lazy, Allocator>::~hash_table ()
729{
730 check_complete_insertion ();
731
732 if (!Lazy || m_entries)
733 {
734 for (size_t i = m_size - 1; i < m_size; i--)
735 if (!is_empty (m_entries[i]) && !is_deleted (v&: m_entries[i]))
736 Descriptor::remove (m_entries[i]);
737
738 if (!m_ggc)
739 Allocator <value_type> ::data_free (m_entries);
740 else
741 ggc_free (m_entries);
742 if (m_gather_mem_stats)
743 hash_table_usage ().release_instance_overhead (ptr: this,
744 size: sizeof (value_type)
745 * m_size, remove_from_map: true);
746 }
747 else if (m_gather_mem_stats)
748 hash_table_usage ().unregister_descriptor (ptr: this);
749}
750
751/* This function returns an array of empty hash table elements. */
752
753template<typename Descriptor, bool Lazy,
754 template<typename Type> class Allocator>
755inline typename hash_table<Descriptor, Lazy, Allocator>::value_type *
756hash_table<Descriptor, Lazy,
757 Allocator>::alloc_entries (size_t n MEM_STAT_DECL) const
758{
759 value_type *nentries;
760
761 if (m_gather_mem_stats)
762 hash_table_usage ().register_instance_overhead (size: sizeof (value_type) * n, ptr: this);
763
764 if (!m_ggc)
765 nentries = Allocator <value_type> ::data_alloc (n);
766 else
767 nentries = ::ggc_cleared_vec_alloc<value_type> (n PASS_MEM_STAT);
768
769 gcc_assert (nentries != NULL);
770 if (!Descriptor::empty_zero_p)
771 for (size_t i = 0; i < n; i++)
772 mark_empty (v&: nentries[i]);
773
774 return nentries;
775}
776
777/* Similar to find_slot, but without several unwanted side effects:
778 - Does not call equal when it finds an existing entry.
779 - Does not change the count of elements/searches/collisions in the
780 hash table.
781 This function also assumes there are no deleted entries in the table.
782 HASH is the hash value for the element to be inserted. */
783
784template<typename Descriptor, bool Lazy,
785 template<typename Type> class Allocator>
786typename hash_table<Descriptor, Lazy, Allocator>::value_type *
787hash_table<Descriptor, Lazy,
788 Allocator>::find_empty_slot_for_expand (hashval_t hash)
789{
790 hashval_t index = hash_table_mod1 (hash, index: m_size_prime_index);
791 size_t size = m_size;
792 value_type *slot = m_entries + index;
793 hashval_t hash2;
794
795 if (is_empty (*slot))
796 return slot;
797 gcc_checking_assert (!is_deleted (*slot));
798
799 hash2 = hash_table_mod2 (hash, index: m_size_prime_index);
800 for (;;)
801 {
802 index += hash2;
803 if (index >= size)
804 index -= size;
805
806 slot = m_entries + index;
807 if (is_empty (*slot))
808 return slot;
809 gcc_checking_assert (!is_deleted (*slot));
810 }
811}
812
813/* Return true if the current table is excessively big for ELTS elements. */
814
815template<typename Descriptor, bool Lazy,
816 template<typename Type> class Allocator>
817inline bool
818hash_table<Descriptor, Lazy, Allocator>::too_empty_p (unsigned int elts)
819{
820 return elts * 8 < m_size && m_size > 32;
821}
822
823/* The following function changes size of memory allocated for the
824 entries and repeatedly inserts the table elements. The occupancy
825 of the table after the call will be about 50%. Naturally the hash
826 table must already exist. Remember also that the place of the
827 table entries is changed. If memory allocation fails, this function
828 will abort. */
829
830template<typename Descriptor, bool Lazy,
831 template<typename Type> class Allocator>
832void
833hash_table<Descriptor, Lazy, Allocator>::expand ()
834{
835 check_complete_insertion ();
836
837 value_type *oentries = m_entries;
838 unsigned int oindex = m_size_prime_index;
839 size_t osize = size ();
840 value_type *olimit = oentries + osize;
841 size_t elts = elements ();
842
843 /* Resize only when table after removal of unused elements is either
844 too full or too empty. */
845 unsigned int nindex;
846 size_t nsize;
847 if (elts * 2 > osize || too_empty_p (elts))
848 {
849 nindex = hash_table_higher_prime_index (n: elts * 2);
850 nsize = prime_tab[nindex].prime;
851 }
852 else
853 {
854 nindex = oindex;
855 nsize = osize;
856 }
857
858 value_type *nentries = alloc_entries (n: nsize);
859
860 if (m_gather_mem_stats)
861 hash_table_usage ().release_instance_overhead (ptr: this, size: sizeof (value_type)
862 * osize);
863
864 size_t n_deleted = m_n_deleted;
865
866 m_entries = nentries;
867 m_size = nsize;
868 m_size_prime_index = nindex;
869 m_n_elements -= m_n_deleted;
870 m_n_deleted = 0;
871
872 size_t n_elements = m_n_elements;
873
874 value_type *p = oentries;
875 do
876 {
877 value_type &x = *p;
878
879 if (is_empty (x))
880 ;
881 else if (is_deleted (v&: x))
882 n_deleted--;
883 else
884 {
885 n_elements--;
886 value_type *q = find_empty_slot_for_expand (hash: Descriptor::hash (x));
887 new ((void*) q) value_type (std::move (x));
888 /* After the resources of 'x' have been moved to a new object at 'q',
889 we now have to destroy the 'x' object, to end its lifetime. */
890 x.~value_type ();
891 }
892
893 p++;
894 }
895 while (p < olimit);
896
897 gcc_checking_assert (!n_elements && !n_deleted);
898
899 if (!m_ggc)
900 Allocator <value_type> ::data_free (oentries);
901 else
902 ggc_free (oentries);
903}
904
905/* Implements empty() in cases where it isn't a no-op. */
906
907template<typename Descriptor, bool Lazy,
908 template<typename Type> class Allocator>
909void
910hash_table<Descriptor, Lazy, Allocator>::empty_slow ()
911{
912 check_complete_insertion ();
913
914 size_t size = m_size;
915 size_t nsize = size;
916 value_type *entries = m_entries;
917
918 for (size_t i = size - 1; i < size; i--)
919 if (!is_empty (entries[i]) && !is_deleted (v&: entries[i]))
920 Descriptor::remove (entries[i]);
921
922 /* Instead of clearing megabyte, downsize the table. */
923 if (size > 1024*1024 / sizeof (value_type))
924 nsize = 1024 / sizeof (value_type);
925 else if (too_empty_p (elts: m_n_elements))
926 nsize = m_n_elements * 2;
927
928 if (nsize != size)
929 {
930 unsigned int nindex = hash_table_higher_prime_index (n: nsize);
931
932 nsize = prime_tab[nindex].prime;
933
934 if (!m_ggc)
935 Allocator <value_type> ::data_free (m_entries);
936 else
937 ggc_free (m_entries);
938
939 m_entries = alloc_entries (n: nsize);
940 m_size = nsize;
941 m_size_prime_index = nindex;
942 }
943 else if (Descriptor::empty_zero_p)
944 memset (s: (void *) entries, c: 0, n: size * sizeof (value_type));
945 else
946 for (size_t i = 0; i < size; i++)
947 mark_empty (v&: entries[i]);
948
949 m_n_deleted = 0;
950 m_n_elements = 0;
951}
952
953/* This function clears a specified SLOT in a hash table. It is
954 useful when you've already done the lookup and don't want to do it
955 again. */
956
957template<typename Descriptor, bool Lazy,
958 template<typename Type> class Allocator>
959void
960hash_table<Descriptor, Lazy, Allocator>::clear_slot (value_type *slot)
961{
962 check_complete_insertion ();
963
964 gcc_checking_assert (!(slot < m_entries || slot >= m_entries + size ()
965 || is_empty (*slot) || is_deleted (*slot)));
966
967 Descriptor::remove (*slot);
968
969 mark_deleted (v&: *slot);
970 m_n_deleted++;
971}
972
973/* This function searches for a hash table entry equal to the given
974 COMPARABLE element starting with the given HASH value. It cannot
975 be used to insert or delete an element. */
976
977template<typename Descriptor, bool Lazy,
978 template<typename Type> class Allocator>
979typename hash_table<Descriptor, Lazy, Allocator>::value_type &
980hash_table<Descriptor, Lazy, Allocator>
981::find_with_hash (const compare_type &comparable, hashval_t hash)
982{
983 m_searches++;
984 size_t size = m_size;
985 hashval_t index = hash_table_mod1 (hash, index: m_size_prime_index);
986
987 if (Lazy && m_entries == NULL)
988 m_entries = alloc_entries (n: size);
989
990 check_complete_insertion ();
991
992#if CHECKING_P
993 if (m_sanitize_eq_and_hash)
994 verify (comparable, hash);
995#endif
996
997 value_type *entry = &m_entries[index];
998 if (is_empty (*entry)
999 || (!is_deleted (v&: *entry) && Descriptor::equal (*entry, comparable)))
1000 return *entry;
1001
1002 hashval_t hash2 = hash_table_mod2 (hash, index: m_size_prime_index);
1003 for (;;)
1004 {
1005 m_collisions++;
1006 index += hash2;
1007 if (index >= size)
1008 index -= size;
1009
1010 entry = &m_entries[index];
1011 if (is_empty (*entry)
1012 || (!is_deleted (v&: *entry) && Descriptor::equal (*entry, comparable)))
1013 return *entry;
1014 }
1015}
1016
1017/* This function searches for a hash table slot containing an entry
1018 equal to the given COMPARABLE element and starting with the given
1019 HASH. To delete an entry, call this with insert=NO_INSERT, then
1020 call clear_slot on the slot returned (possibly after doing some
1021 checks). To insert an entry, call this with insert=INSERT, then
1022 write the value you want into the returned slot. When inserting an
1023 entry, NULL may be returned if memory allocation fails. */
1024
1025template<typename Descriptor, bool Lazy,
1026 template<typename Type> class Allocator>
1027typename hash_table<Descriptor, Lazy, Allocator>::value_type *
1028hash_table<Descriptor, Lazy, Allocator>
1029::find_slot_with_hash (const compare_type &comparable, hashval_t hash,
1030 enum insert_option insert)
1031{
1032 if (Lazy && m_entries == NULL)
1033 {
1034 if (insert == INSERT)
1035 m_entries = alloc_entries (n: m_size);
1036 else
1037 return NULL;
1038 }
1039 if (insert == INSERT && m_size * 3 <= m_n_elements * 4)
1040 expand ();
1041 else
1042 check_complete_insertion ();
1043
1044#if CHECKING_P
1045 if (m_sanitize_eq_and_hash)
1046 verify (comparable, hash);
1047#endif
1048
1049 m_searches++;
1050 value_type *first_deleted_slot = NULL;
1051 hashval_t index = hash_table_mod1 (hash, index: m_size_prime_index);
1052 hashval_t hash2 = hash_table_mod2 (hash, index: m_size_prime_index);
1053 value_type *entry = &m_entries[index];
1054 size_t size = m_size;
1055 if (is_empty (*entry))
1056 goto empty_entry;
1057 else if (is_deleted (v&: *entry))
1058 first_deleted_slot = &m_entries[index];
1059 else if (Descriptor::equal (*entry, comparable))
1060 return &m_entries[index];
1061
1062 for (;;)
1063 {
1064 m_collisions++;
1065 index += hash2;
1066 if (index >= size)
1067 index -= size;
1068
1069 entry = &m_entries[index];
1070 if (is_empty (*entry))
1071 goto empty_entry;
1072 else if (is_deleted (v&: *entry))
1073 {
1074 if (!first_deleted_slot)
1075 first_deleted_slot = &m_entries[index];
1076 }
1077 else if (Descriptor::equal (*entry, comparable))
1078 return &m_entries[index];
1079 }
1080
1081 empty_entry:
1082 if (insert == NO_INSERT)
1083 return NULL;
1084
1085 if (first_deleted_slot)
1086 {
1087 m_n_deleted--;
1088 mark_empty (v&: *first_deleted_slot);
1089 return check_insert_slot (ret: first_deleted_slot);
1090 }
1091
1092 m_n_elements++;
1093 return check_insert_slot (ret: &m_entries[index]);
1094}
1095
1096/* Verify that all existing elements in the hash table which are
1097 equal to COMPARABLE have an equal HASH value provided as argument.
1098 Also check that the hash table element counts are correct. */
1099
1100template<typename Descriptor, bool Lazy,
1101 template<typename Type> class Allocator>
1102void
1103hash_table<Descriptor, Lazy, Allocator>
1104::verify (const compare_type &comparable, hashval_t hash)
1105{
1106 size_t n_elements = m_n_elements;
1107 size_t n_deleted = m_n_deleted;
1108 for (size_t i = 0; i < MIN (hash_table_sanitize_eq_limit, m_size); i++)
1109 {
1110 value_type *entry = &m_entries[i];
1111 if (!is_empty (*entry))
1112 {
1113 n_elements--;
1114 if (is_deleted (v&: *entry))
1115 n_deleted--;
1116 else if (hash != Descriptor::hash (*entry)
1117 && Descriptor::equal (*entry, comparable))
1118 hashtab_chk_error ();
1119 }
1120 }
1121 if (hash_table_sanitize_eq_limit >= m_size)
1122 gcc_checking_assert (!n_elements && !n_deleted);
1123}
1124
1125/* This function deletes an element with the given COMPARABLE value
1126 from hash table starting with the given HASH. If there is no
1127 matching element in the hash table, this function does nothing. */
1128
1129template<typename Descriptor, bool Lazy,
1130 template<typename Type> class Allocator>
1131void
1132hash_table<Descriptor, Lazy, Allocator>
1133::remove_elt_with_hash (const compare_type &comparable, hashval_t hash)
1134{
1135 check_complete_insertion ();
1136
1137 value_type *slot = find_slot_with_hash (comparable, hash, insert: NO_INSERT);
1138 if (slot == NULL)
1139 return;
1140
1141 Descriptor::remove (*slot);
1142
1143 mark_deleted (v&: *slot);
1144 m_n_deleted++;
1145}
1146
1147/* This function scans over the entire hash table calling CALLBACK for
1148 each live entry. If CALLBACK returns false, the iteration stops.
1149 ARGUMENT is passed as CALLBACK's second argument. */
1150
1151template<typename Descriptor, bool Lazy,
1152 template<typename Type> class Allocator>
1153template<typename Argument,
1154 int (*Callback)
1155 (typename hash_table<Descriptor, Lazy, Allocator>::value_type *slot,
1156 Argument argument)>
1157void
1158hash_table<Descriptor, Lazy, Allocator>::traverse_noresize (Argument argument)
1159{
1160 if (Lazy && m_entries == NULL)
1161 return;
1162
1163 check_complete_insertion ();
1164
1165 value_type *slot = m_entries;
1166 value_type *limit = slot + size ();
1167
1168 do
1169 {
1170 value_type &x = *slot;
1171
1172 if (!is_empty (x) && !is_deleted (v&: x))
1173 if (! Callback (slot, argument))
1174 break;
1175 }
1176 while (++slot < limit);
1177}
1178
1179/* Like traverse_noresize, but does resize the table when it is too empty
1180 to improve effectivity of subsequent calls. */
1181
1182template <typename Descriptor, bool Lazy,
1183 template <typename Type> class Allocator>
1184template <typename Argument,
1185 int (*Callback)
1186 (typename hash_table<Descriptor, Lazy, Allocator>::value_type *slot,
1187 Argument argument)>
1188void
1189hash_table<Descriptor, Lazy, Allocator>::traverse (Argument argument)
1190{
1191 if (too_empty_p (elts: elements ()) && (!Lazy || m_entries))
1192 expand ();
1193
1194 traverse_noresize <Argument, Callback> (argument);
1195}
1196
1197/* Slide down the iterator slots until an active entry is found. */
1198
1199template<typename Descriptor, bool Lazy,
1200 template<typename Type> class Allocator>
1201void
1202hash_table<Descriptor, Lazy, Allocator>::iterator::slide ()
1203{
1204 for ( ; m_slot < m_limit; ++m_slot )
1205 {
1206 value_type &x = *m_slot;
1207 if (!is_empty (x) && !is_deleted (v&: x))
1208 return;
1209 }
1210 m_slot = NULL;
1211 m_limit = NULL;
1212}
1213
1214/* Bump the iterator. */
1215
1216template<typename Descriptor, bool Lazy,
1217 template<typename Type> class Allocator>
1218inline typename hash_table<Descriptor, Lazy, Allocator>::iterator &
1219hash_table<Descriptor, Lazy, Allocator>::iterator::operator ++ ()
1220{
1221 ++m_slot;
1222 slide ();
1223 return *this;
1224}
1225
1226
1227/* Iterate through the elements of hash_table HTAB,
1228 using hash_table <....>::iterator ITER,
1229 storing each element in RESULT, which is of type TYPE. */
1230
1231#define FOR_EACH_HASH_TABLE_ELEMENT(HTAB, RESULT, TYPE, ITER) \
1232 for ((ITER) = (HTAB).begin (); \
1233 (ITER) != (HTAB).end () ? (RESULT = *(ITER) , true) : false; \
1234 ++(ITER))
1235
1236/* ggc walking routines. */
1237
1238template<typename E>
1239inline void
1240gt_ggc_mx (hash_table<E> *h)
1241{
1242 typedef hash_table<E> table;
1243
1244 if (!ggc_test_and_set_mark (h->m_entries))
1245 return;
1246
1247 for (size_t i = 0; i < h->m_size; i++)
1248 {
1249 if (table::is_empty (h->m_entries[i])
1250 || table::is_deleted (h->m_entries[i]))
1251 continue;
1252
1253 /* Use ggc_maxbe_mx so we don't mark right away for cache tables; we'll
1254 mark in gt_cleare_cache if appropriate. */
1255 E::ggc_maybe_mx (h->m_entries[i]);
1256 }
1257}
1258
1259template<typename D>
1260inline void
1261hashtab_entry_note_pointers (void *obj, void *h, gt_pointer_operator op,
1262 void *cookie)
1263{
1264 hash_table<D> *map = static_cast<hash_table<D> *> (h);
1265 gcc_checking_assert (map->m_entries == obj);
1266 for (size_t i = 0; i < map->m_size; i++)
1267 {
1268 typedef hash_table<D> table;
1269 if (table::is_empty (map->m_entries[i])
1270 || table::is_deleted (map->m_entries[i]))
1271 continue;
1272
1273 D::pch_nx (map->m_entries[i], op, cookie);
1274 }
1275}
1276
1277template<typename D>
1278void
1279gt_pch_nx (hash_table<D> *h)
1280{
1281 h->check_complete_insertion ();
1282 bool success
1283 = gt_pch_note_object (h->m_entries, h, hashtab_entry_note_pointers<D>);
1284 gcc_checking_assert (success);
1285 for (size_t i = 0; i < h->m_size; i++)
1286 {
1287 if (hash_table<D>::is_empty (h->m_entries[i])
1288 || hash_table<D>::is_deleted (h->m_entries[i]))
1289 continue;
1290
1291 D::pch_nx (h->m_entries[i]);
1292 }
1293}
1294
1295template<typename D>
1296inline void
1297gt_pch_nx (hash_table<D> *h, gt_pointer_operator op, void *cookie)
1298{
1299 op (&h->m_entries, NULL, cookie);
1300}
1301
1302template<typename H>
1303inline void
1304gt_cleare_cache (hash_table<H> *h)
1305{
1306 typedef hash_table<H> table;
1307 if (!h)
1308 return;
1309
1310 for (typename table::iterator iter = h->begin (); iter != h->end (); ++iter)
1311 if (!table::is_empty (*iter) && !table::is_deleted (*iter))
1312 {
1313 int res = H::keep_cache_entry (*iter);
1314 if (res == 0)
1315 h->clear_slot (&*iter);
1316 else if (res != -1)
1317 H::ggc_mx (*iter);
1318 }
1319}
1320
1321#endif /* TYPED_HASHTAB_H */
1322

source code of gcc/hash-table.h