1 /* A type-safe hash table template.
2 Copyright (C) 2012-2019 Free Software Foundation, Inc.
3 Contributed by Lawrence Crowl <crowl@google.com>
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it under
8 the terms of the GNU General Public License as published by the Free
9 Software Foundation; either version 3, or (at your option) any later
12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING3. If not see
19 <http://www.gnu.org/licenses/>. */
22 /* This file implements a typed hash table.
23 The implementation borrows from libiberty's htab_t in hashtab.h.
28 Users of the hash table generally need to be aware of three types.
30 1. The type being placed into the hash table. This type is called
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
37 - A typedef named 'value_type' to the value type (from above).
39 - A static member function named 'hash' that takes a value_type
40 (or 'const value_type &') and returns a hashval_t value.
42 - A typedef named 'compare_type' that is used to test when a value
43 is found. This type is the comparison type. Usually, it will be the
44 same as value_type. If it is not the same type, you must generally
45 explicitly compute hash values and pass them to the hash table.
47 - A static member function named 'equal' that takes a value_type
48 and a compare_type, and returns a bool. Both arguments can be
51 - A static function named 'remove' that takes an value_type pointer
52 and frees the memory allocated by it. This function is used when
53 individual elements of the table need to be disposed of (e.g.,
54 when deleting a hash table, removing elements from the table, etc).
56 - An optional static function named 'keep_cache_entry'. This
57 function is provided only for garbage-collected elements that
58 are not marked by the normal gc mark pass. It describes what
59 what should happen to the element at the end of the gc mark phase.
60 The return value should be:
61 - 0 if the element should be deleted
62 - 1 if the element should be kept and needs to be marked
63 - -1 if the element should be kept and is already marked.
64 Returning -1 rather than 1 is purely an optimization.
66 3. The type of the hash table itself. (More later.)
68 In very special circumstances, users may need to know about a fourth type.
70 4. The template type used to describe how hash table memory
71 is allocated. This type is called the allocator type. It is
72 parameterized on the value type. It provides two functions:
74 - A static member function named 'data_alloc'. This function
75 allocates the data elements in the table.
77 - A static member function named 'data_free'. This function
78 deallocates the data elements in the table.
80 Hash table are instantiated with two type arguments.
82 * The descriptor type, (2) above.
84 * The allocator type, (4) above. In general, you will not need to
85 provide your own allocator type. By default, hash tables will use
86 the class template xcallocator, which uses malloc/free for allocation.
89 DEFINING A DESCRIPTOR TYPE
91 The first task in using the hash table is to describe the element type.
92 We compose this into a few steps.
94 1. Decide on a removal policy for values stored in the table.
95 hash-traits.h provides class templates for the four most common
98 * typed_free_remove implements the static 'remove' member function
101 * typed_noop_remove implements the static 'remove' member function
104 * ggc_remove implements the static 'remove' member by doing nothing,
105 but instead provides routines for gc marking and for PCH streaming.
106 Use this for garbage-collected data that needs to be preserved across
109 * ggc_cache_remove is like ggc_remove, except that it does not
110 mark the entries during the normal gc mark phase. Instead it
111 uses 'keep_cache_entry' (described above) to keep elements that
112 were not collected and delete those that were. Use this for
113 garbage-collected caches that should not in themselves stop
114 the data from being collected.
116 You can use these policies by simply deriving the descriptor type
117 from one of those class template, with the appropriate argument.
119 Otherwise, you need to write the static 'remove' member function
120 in the descriptor class.
122 2. Choose a hash function. Write the static 'hash' member function.
124 3. Decide whether the lookup function should take as input an object
125 of type value_type or something more restricted. Define compare_type
128 4. Choose an equality testing function 'equal' that compares a value_type
131 If your elements are pointers, it is usually easiest to start with one
132 of the generic pointer descriptors described below and override the bits
135 AN EXAMPLE DESCRIPTOR TYPE
137 Suppose you want to put some_type into the hash table. You could define
138 the descriptor type as follows.
140 struct some_type_hasher : nofree_ptr_hash <some_type>
141 // Deriving from nofree_ptr_hash means that we get a 'remove' that does
142 // nothing. This choice is good for raw values.
144 static inline hashval_t hash (const value_type *);
145 static inline bool equal (const value_type *, const compare_type *);
149 some_type_hasher::hash (const value_type *e)
150 { ... compute and return a hash value for E ... }
153 some_type_hasher::equal (const value_type *p1, const compare_type *p2)
154 { ... compare P1 vs P2. Return true if they are the 'same' ... }
157 AN EXAMPLE HASH_TABLE DECLARATION
159 To instantiate a hash table for some_type:
161 hash_table <some_type_hasher> some_type_hash_table;
163 There is no need to mention some_type directly, as the hash table will
164 obtain it using some_type_hasher::value_type.
166 You can then use any of the functions in hash_table's public interface.
167 See hash_table for details. The interface is very similar to libiberty's
170 If a hash table is used only in some rare cases, it is possible
171 to construct the hash_table lazily before first use. This is done
174 hash_table <some_type_hasher, true> some_type_hash_table;
176 which will cause whatever methods actually need the allocated entries
177 array to allocate it later.
180 EASY DESCRIPTORS FOR POINTERS
182 There are four descriptors for pointer elements, one for each of
183 the removal policies above:
185 * nofree_ptr_hash (based on typed_noop_remove)
186 * free_ptr_hash (based on typed_free_remove)
187 * ggc_ptr_hash (based on ggc_remove)
188 * ggc_cache_ptr_hash (based on ggc_cache_remove)
190 These descriptors hash and compare elements by their pointer value,
191 rather than what they point to. So, to instantiate a hash table over
192 pointers to whatever_type, without freeing the whatever_types, use:
194 hash_table <nofree_ptr_hash <whatever_type> > whatever_type_hash_table;
199 The hash table provides standard C++ iterators. For example, consider a
200 hash table of some_info. We wish to consume each element of the table:
202 extern void consume (some_info *);
204 We define a convenience typedef and the hash table:
206 typedef hash_table <some_info_hasher> info_table_type;
207 info_table_type info_table;
209 Then we write the loop in typical C++ style:
211 for (info_table_type::iterator iter = info_table.begin ();
212 iter != info_table.end ();
214 if ((*iter).status == INFO_READY)
217 Or with common sub-expression elimination:
219 for (info_table_type::iterator iter = info_table.begin ();
220 iter != info_table.end ();
223 some_info &elem = *iter;
224 if (elem.status == INFO_READY)
228 One can also use a more typical GCC style:
230 typedef some_info *some_info_p;
232 info_table_type::iterator iter;
233 FOR_EACH_HASH_TABLE_ELEMENT (info_table, elem_ptr, some_info_p, iter)
234 if (elem_ptr->status == INFO_READY)
240 #ifndef TYPED_HASHTAB_H
241 #define TYPED_HASHTAB_H
243 #include "statistics.h"
248 #include "mem-stats-traits.h"
249 #include "hash-traits.h"
250 #include "hash-map-traits.h"
252 template<typename, typename, typename> class hash_map;
253 template<typename, bool, typename> class hash_set;
255 /* The ordinary memory allocator. */
256 /* FIXME (crowl): This allocator may be extracted for wider sharing later. */
258 template <typename Type>
261 static Type *data_alloc (size_t count);
262 static void data_free (Type *memory);
266 /* Allocate memory for COUNT data blocks. */
268 template <typename Type>
270 xcallocator <Type>::data_alloc (size_t count)
272 return static_cast <Type *> (xcalloc (count, sizeof (Type)));
276 /* Free memory for data blocks. */
278 template <typename Type>
280 xcallocator <Type>::data_free (Type *memory)
282 return ::free (memory);
286 /* Table of primes and their inversion information. */
292 hashval_t inv_m2; /* inverse of prime-2 */
296 extern struct prime_ent const prime_tab[];
299 /* Functions for computing hash table indexes. */
301 extern unsigned int hash_table_higher_prime_index (unsigned long n)
304 /* Return X % Y using multiplicative inverse values INV and SHIFT.
306 The multiplicative inverses computed above are for 32-bit types,
307 and requires that we be able to compute a highpart multiply.
309 FIX: I am not at all convinced that
310 3 loads, 2 multiplications, 3 shifts, and 3 additions
313 on modern systems running a compiler. */
316 mul_mod (hashval_t x, hashval_t y, hashval_t inv, int shift)
318 hashval_t t1, t2, t3, t4, q, r;
320 t1 = ((uint64_t)x * inv) >> 32;
330 /* Compute the primary table index for HASH given current prime index. */
333 hash_table_mod1 (hashval_t hash, unsigned int index)
335 const struct prime_ent *p = &prime_tab[index];
336 gcc_checking_assert (sizeof (hashval_t) * CHAR_BIT <= 32);
337 return mul_mod (hash, p->prime, p->inv, p->shift);
340 /* Compute the secondary table index for HASH given current prime index. */
343 hash_table_mod2 (hashval_t hash, unsigned int index)
345 const struct prime_ent *p = &prime_tab[index];
346 gcc_checking_assert (sizeof (hashval_t) * CHAR_BIT <= 32);
347 return 1 + mul_mod (hash, p->prime - 2, p->inv_m2, p->shift);
352 /* User-facing hash table type.
354 The table stores elements of type Descriptor::value_type and uses
355 the static descriptor functions described at the top of the file
356 to hash, compare and remove elements.
358 Specify the template Allocator to allocate and free memory.
359 The default is xcallocator.
361 Storage is an implementation detail and should not be used outside the
365 template <typename Descriptor, bool Lazy = false,
366 template<typename Type> class Allocator = xcallocator>
369 typedef typename Descriptor::value_type value_type;
370 typedef typename Descriptor::compare_type compare_type;
373 explicit hash_table (size_t, bool ggc = false,
374 bool gather_mem_stats = GATHER_STATISTICS,
375 mem_alloc_origin origin = HASH_TABLE_ORIGIN
377 explicit hash_table (const hash_table &, bool ggc = false,
378 bool gather_mem_stats = GATHER_STATISTICS,
379 mem_alloc_origin origin = HASH_TABLE_ORIGIN
383 /* Create a hash_table in gc memory. */
385 create_ggc (size_t n CXX_MEM_STAT_INFO)
387 hash_table *table = ggc_alloc<hash_table> ();
388 new (table) hash_table (n, true, GATHER_STATISTICS,
389 HASH_TABLE_ORIGIN PASS_MEM_STAT);
393 /* Current size (in entries) of the hash table. */
394 size_t size () const { return m_size; }
396 /* Return the current number of elements in this hash table. */
397 size_t elements () const { return m_n_elements - m_n_deleted; }
399 /* Return the current number of elements in this hash table. */
400 size_t elements_with_deleted () const { return m_n_elements; }
402 /* This function clears all entries in this hash table. */
403 void empty () { if (elements ()) empty_slow (); }
405 /* This function clears a specified SLOT in a hash table. It is
406 useful when you've already done the lookup and don't want to do it
408 void clear_slot (value_type *);
410 /* This function searches for a hash table entry equal to the given
411 COMPARABLE element starting with the given HASH value. It cannot
412 be used to insert or delete an element. */
413 value_type &find_with_hash (const compare_type &, hashval_t);
415 /* Like find_slot_with_hash, but compute the hash value from the element. */
416 value_type &find (const value_type &value)
418 return find_with_hash (value, Descriptor::hash (value));
421 value_type *find_slot (const value_type &value, insert_option insert)
423 return find_slot_with_hash (value, Descriptor::hash (value), insert);
426 /* This function searches for a hash table slot containing an entry
427 equal to the given COMPARABLE element and starting with the given
428 HASH. To delete an entry, call this with insert=NO_INSERT, then
429 call clear_slot on the slot returned (possibly after doing some
430 checks). To insert an entry, call this with insert=INSERT, then
431 write the value you want into the returned slot. When inserting an
432 entry, NULL may be returned if memory allocation fails. */
433 value_type *find_slot_with_hash (const compare_type &comparable,
434 hashval_t hash, enum insert_option insert);
436 /* This function deletes an element with the given COMPARABLE value
437 from hash table starting with the given HASH. If there is no
438 matching element in the hash table, this function does nothing. */
439 void remove_elt_with_hash (const compare_type &, hashval_t);
441 /* Like remove_elt_with_hash, but compute the hash value from the
443 void remove_elt (const value_type &value)
445 remove_elt_with_hash (value, Descriptor::hash (value));
448 /* This function scans over the entire hash table calling CALLBACK for
449 each live entry. If CALLBACK returns false, the iteration stops.
450 ARGUMENT is passed as CALLBACK's second argument. */
451 template <typename Argument,
452 int (*Callback) (value_type *slot, Argument argument)>
453 void traverse_noresize (Argument argument);
455 /* Like traverse_noresize, but does resize the table when it is too empty
456 to improve effectivity of subsequent calls. */
457 template <typename Argument,
458 int (*Callback) (value_type *slot, Argument argument)>
459 void traverse (Argument argument);
464 iterator () : m_slot (NULL), m_limit (NULL) {}
466 iterator (value_type *slot, value_type *limit) :
467 m_slot (slot), m_limit (limit) {}
469 inline value_type &operator * () { return *m_slot; }
471 inline iterator &operator ++ ();
472 bool operator != (const iterator &other) const
474 return m_slot != other.m_slot || m_limit != other.m_limit;
482 iterator begin () const
484 if (Lazy && m_entries == NULL)
486 iterator iter (m_entries, m_entries + m_size);
491 iterator end () const { return iterator (); }
493 double collisions () const
495 return m_searches ? static_cast <double> (m_collisions) / m_searches : 0;
499 template<typename T> friend void gt_ggc_mx (hash_table<T> *);
500 template<typename T> friend void gt_pch_nx (hash_table<T> *);
501 template<typename T> friend void
502 hashtab_entry_note_pointers (void *, void *, gt_pointer_operator, void *);
503 template<typename T, typename U, typename V> friend void
504 gt_pch_nx (hash_map<T, U, V> *, gt_pointer_operator, void *);
505 template<typename T, typename U>
506 friend void gt_pch_nx (hash_set<T, false, U> *, gt_pointer_operator, void *);
507 template<typename T> friend void gt_pch_nx (hash_table<T> *,
508 gt_pointer_operator, void *);
510 template<typename T> friend void gt_cleare_cache (hash_table<T> *);
514 value_type *alloc_entries (size_t n CXX_MEM_STAT_INFO) const;
515 value_type *find_empty_slot_for_expand (hashval_t);
516 bool too_empty_p (unsigned int);
518 static bool is_deleted (value_type &v)
520 return Descriptor::is_deleted (v);
523 static bool is_empty (value_type &v)
525 return Descriptor::is_empty (v);
528 static void mark_deleted (value_type &v)
530 Descriptor::mark_deleted (v);
533 static void mark_empty (value_type &v)
535 Descriptor::mark_empty (v);
539 typename Descriptor::value_type *m_entries;
543 /* Current number of elements including also deleted elements. */
546 /* Current number of deleted elements in the table. */
549 /* The following member is used for debugging. Its value is number
550 of all calls of `htab_find_slot' for the hash table. */
551 unsigned int m_searches;
553 /* The following member is used for debugging. Its value is number
554 of collisions fixed for time of work with the hash table. */
555 unsigned int m_collisions;
557 /* Current size (in entries) of the hash table, as an index into the
559 unsigned int m_size_prime_index;
561 /* if m_entries is stored in ggc memory. */
564 /* If we should gather memory statistics for the table. */
565 bool m_gather_mem_stats;
568 /* As mem-stats.h heavily utilizes hash maps (hash tables), we have to include
569 mem-stats.h after hash_table declaration. */
571 #include "mem-stats.h"
572 #include "hash-map.h"
574 extern mem_alloc_description<mem_usage>& hash_table_usage (void);
576 /* Support function for statistics. */
577 extern void dump_hash_table_loc_statistics (void);
579 template<typename Descriptor, bool Lazy,
580 template<typename Type> class Allocator>
581 hash_table<Descriptor, Lazy, Allocator>::hash_table (size_t size, bool ggc,
582 bool gather_mem_stats,
583 mem_alloc_origin origin
585 m_n_elements (0), m_n_deleted (0), m_searches (0), m_collisions (0),
586 m_ggc (ggc), m_gather_mem_stats (gather_mem_stats)
588 unsigned int size_prime_index;
590 size_prime_index = hash_table_higher_prime_index (size);
591 size = prime_tab[size_prime_index].prime;
593 if (m_gather_mem_stats)
594 hash_table_usage ().register_descriptor (this, origin, ggc
595 FINAL_PASS_MEM_STAT);
600 m_entries = alloc_entries (size PASS_MEM_STAT);
602 m_size_prime_index = size_prime_index;
605 template<typename Descriptor, bool Lazy,
606 template<typename Type> class Allocator>
607 hash_table<Descriptor, Lazy, Allocator>::hash_table (const hash_table &h,
609 bool gather_mem_stats,
610 mem_alloc_origin origin
612 m_n_elements (h.m_n_elements), m_n_deleted (h.m_n_deleted),
613 m_searches (0), m_collisions (0), m_ggc (ggc),
614 m_gather_mem_stats (gather_mem_stats)
616 size_t size = h.m_size;
618 if (m_gather_mem_stats)
619 hash_table_usage ().register_descriptor (this, origin, ggc
620 FINAL_PASS_MEM_STAT);
622 if (Lazy && h.m_entries == NULL)
626 value_type *nentries = alloc_entries (size PASS_MEM_STAT);
627 for (size_t i = 0; i < size; ++i)
629 value_type &entry = h.m_entries[i];
630 if (is_deleted (entry))
631 mark_deleted (nentries[i]);
632 else if (!is_empty (entry))
635 m_entries = nentries;
638 m_size_prime_index = h.m_size_prime_index;
641 template<typename Descriptor, bool Lazy,
642 template<typename Type> class Allocator>
643 hash_table<Descriptor, Lazy, Allocator>::~hash_table ()
645 if (!Lazy || m_entries)
647 for (size_t i = m_size - 1; i < m_size; i--)
648 if (!is_empty (m_entries[i]) && !is_deleted (m_entries[i]))
649 Descriptor::remove (m_entries[i]);
652 Allocator <value_type> ::data_free (m_entries);
654 ggc_free (m_entries);
655 if (m_gather_mem_stats)
656 hash_table_usage ().release_instance_overhead (this,
660 else if (m_gather_mem_stats)
661 hash_table_usage ().unregister_descriptor (this);
664 /* This function returns an array of empty hash table elements. */
666 template<typename Descriptor, bool Lazy,
667 template<typename Type> class Allocator>
668 inline typename hash_table<Descriptor, Lazy, Allocator>::value_type *
669 hash_table<Descriptor, Lazy,
670 Allocator>::alloc_entries (size_t n MEM_STAT_DECL) const
672 value_type *nentries;
674 if (m_gather_mem_stats)
675 hash_table_usage ().register_instance_overhead (sizeof (value_type) * n, this);
678 nentries = Allocator <value_type> ::data_alloc (n);
680 nentries = ::ggc_cleared_vec_alloc<value_type> (n PASS_MEM_STAT);
682 gcc_assert (nentries != NULL);
683 for (size_t i = 0; i < n; i++)
684 mark_empty (nentries[i]);
689 /* Similar to find_slot, but without several unwanted side effects:
690 - Does not call equal when it finds an existing entry.
691 - Does not change the count of elements/searches/collisions in the
693 This function also assumes there are no deleted entries in the table.
694 HASH is the hash value for the element to be inserted. */
696 template<typename Descriptor, bool Lazy,
697 template<typename Type> class Allocator>
698 typename hash_table<Descriptor, Lazy, Allocator>::value_type *
699 hash_table<Descriptor, Lazy,
700 Allocator>::find_empty_slot_for_expand (hashval_t hash)
702 hashval_t index = hash_table_mod1 (hash, m_size_prime_index);
703 size_t size = m_size;
704 value_type *slot = m_entries + index;
707 if (is_empty (*slot))
709 gcc_checking_assert (!is_deleted (*slot));
711 hash2 = hash_table_mod2 (hash, m_size_prime_index);
718 slot = m_entries + index;
719 if (is_empty (*slot))
721 gcc_checking_assert (!is_deleted (*slot));
725 /* Return true if the current table is excessively big for ELTS elements. */
727 template<typename Descriptor, bool Lazy,
728 template<typename Type> class Allocator>
730 hash_table<Descriptor, Lazy, Allocator>::too_empty_p (unsigned int elts)
732 return elts * 8 < m_size && m_size > 32;
735 /* The following function changes size of memory allocated for the
736 entries and repeatedly inserts the table elements. The occupancy
737 of the table after the call will be about 50%. Naturally the hash
738 table must already exist. Remember also that the place of the
739 table entries is changed. If memory allocation fails, this function
742 template<typename Descriptor, bool Lazy,
743 template<typename Type> class Allocator>
745 hash_table<Descriptor, Lazy, Allocator>::expand ()
747 value_type *oentries = m_entries;
748 unsigned int oindex = m_size_prime_index;
749 size_t osize = size ();
750 value_type *olimit = oentries + osize;
751 size_t elts = elements ();
753 /* Resize only when table after removal of unused elements is either
754 too full or too empty. */
757 if (elts * 2 > osize || too_empty_p (elts))
759 nindex = hash_table_higher_prime_index (elts * 2);
760 nsize = prime_tab[nindex].prime;
768 value_type *nentries = alloc_entries (nsize);
770 if (m_gather_mem_stats)
771 hash_table_usage ().release_instance_overhead (this, sizeof (value_type)
774 m_entries = nentries;
776 m_size_prime_index = nindex;
777 m_n_elements -= m_n_deleted;
780 value_type *p = oentries;
785 if (!is_empty (x) && !is_deleted (x))
787 value_type *q = find_empty_slot_for_expand (Descriptor::hash (x));
797 Allocator <value_type> ::data_free (oentries);
802 /* Implements empty() in cases where it isn't a no-op. */
804 template<typename Descriptor, bool Lazy,
805 template<typename Type> class Allocator>
807 hash_table<Descriptor, Lazy, Allocator>::empty_slow ()
809 size_t size = m_size;
811 value_type *entries = m_entries;
814 for (i = size - 1; i >= 0; i--)
815 if (!is_empty (entries[i]) && !is_deleted (entries[i]))
816 Descriptor::remove (entries[i]);
818 /* Instead of clearing megabyte, downsize the table. */
819 if (size > 1024*1024 / sizeof (value_type))
820 nsize = 1024 / sizeof (value_type);
821 else if (too_empty_p (m_n_elements))
822 nsize = m_n_elements * 2;
826 int nindex = hash_table_higher_prime_index (nsize);
827 int nsize = prime_tab[nindex].prime;
830 Allocator <value_type> ::data_free (m_entries);
832 ggc_free (m_entries);
834 m_entries = alloc_entries (nsize);
836 m_size_prime_index = nindex;
840 #ifndef BROKEN_VALUE_INITIALIZATION
841 for ( ; size; ++entries, --size)
842 *entries = value_type ();
844 memset (entries, 0, size * sizeof (value_type));
851 /* This function clears a specified SLOT in a hash table. It is
852 useful when you've already done the lookup and don't want to do it
855 template<typename Descriptor, bool Lazy,
856 template<typename Type> class Allocator>
858 hash_table<Descriptor, Lazy, Allocator>::clear_slot (value_type *slot)
860 gcc_checking_assert (!(slot < m_entries || slot >= m_entries + size ()
861 || is_empty (*slot) || is_deleted (*slot)));
863 Descriptor::remove (*slot);
865 mark_deleted (*slot);
869 /* This function searches for a hash table entry equal to the given
870 COMPARABLE element starting with the given HASH value. It cannot
871 be used to insert or delete an element. */
873 template<typename Descriptor, bool Lazy,
874 template<typename Type> class Allocator>
875 typename hash_table<Descriptor, Lazy, Allocator>::value_type &
876 hash_table<Descriptor, Lazy, Allocator>
877 ::find_with_hash (const compare_type &comparable, hashval_t hash)
880 size_t size = m_size;
881 hashval_t index = hash_table_mod1 (hash, m_size_prime_index);
883 if (Lazy && m_entries == NULL)
884 m_entries = alloc_entries (size);
885 value_type *entry = &m_entries[index];
886 if (is_empty (*entry)
887 || (!is_deleted (*entry) && Descriptor::equal (*entry, comparable)))
890 hashval_t hash2 = hash_table_mod2 (hash, m_size_prime_index);
898 entry = &m_entries[index];
899 if (is_empty (*entry)
900 || (!is_deleted (*entry) && Descriptor::equal (*entry, comparable)))
905 /* This function searches for a hash table slot containing an entry
906 equal to the given COMPARABLE element and starting with the given
907 HASH. To delete an entry, call this with insert=NO_INSERT, then
908 call clear_slot on the slot returned (possibly after doing some
909 checks). To insert an entry, call this with insert=INSERT, then
910 write the value you want into the returned slot. When inserting an
911 entry, NULL may be returned if memory allocation fails. */
913 template<typename Descriptor, bool Lazy,
914 template<typename Type> class Allocator>
915 typename hash_table<Descriptor, Lazy, Allocator>::value_type *
916 hash_table<Descriptor, Lazy, Allocator>
917 ::find_slot_with_hash (const compare_type &comparable, hashval_t hash,
918 enum insert_option insert)
920 if (Lazy && m_entries == NULL)
922 if (insert == INSERT)
923 m_entries = alloc_entries (m_size);
927 if (insert == INSERT && m_size * 3 <= m_n_elements * 4)
932 value_type *first_deleted_slot = NULL;
933 hashval_t index = hash_table_mod1 (hash, m_size_prime_index);
934 hashval_t hash2 = hash_table_mod2 (hash, m_size_prime_index);
935 value_type *entry = &m_entries[index];
936 size_t size = m_size;
937 if (is_empty (*entry))
939 else if (is_deleted (*entry))
940 first_deleted_slot = &m_entries[index];
941 else if (Descriptor::equal (*entry, comparable))
942 return &m_entries[index];
951 entry = &m_entries[index];
952 if (is_empty (*entry))
954 else if (is_deleted (*entry))
956 if (!first_deleted_slot)
957 first_deleted_slot = &m_entries[index];
959 else if (Descriptor::equal (*entry, comparable))
960 return &m_entries[index];
964 if (insert == NO_INSERT)
967 if (first_deleted_slot)
970 mark_empty (*first_deleted_slot);
971 return first_deleted_slot;
975 return &m_entries[index];
978 /* This function deletes an element with the given COMPARABLE value
979 from hash table starting with the given HASH. If there is no
980 matching element in the hash table, this function does nothing. */
982 template<typename Descriptor, bool Lazy,
983 template<typename Type> class Allocator>
985 hash_table<Descriptor, Lazy, Allocator>
986 ::remove_elt_with_hash (const compare_type &comparable, hashval_t hash)
988 value_type *slot = find_slot_with_hash (comparable, hash, NO_INSERT);
992 Descriptor::remove (*slot);
994 mark_deleted (*slot);
998 /* This function scans over the entire hash table calling CALLBACK for
999 each live entry. If CALLBACK returns false, the iteration stops.
1000 ARGUMENT is passed as CALLBACK's second argument. */
1002 template<typename Descriptor, bool Lazy,
1003 template<typename Type> class Allocator>
1004 template<typename Argument,
1006 (typename hash_table<Descriptor, Lazy, Allocator>::value_type *slot,
1009 hash_table<Descriptor, Lazy, Allocator>::traverse_noresize (Argument argument)
1011 if (Lazy && m_entries == NULL)
1014 value_type *slot = m_entries;
1015 value_type *limit = slot + size ();
1019 value_type &x = *slot;
1021 if (!is_empty (x) && !is_deleted (x))
1022 if (! Callback (slot, argument))
1025 while (++slot < limit);
1028 /* Like traverse_noresize, but does resize the table when it is too empty
1029 to improve effectivity of subsequent calls. */
1031 template <typename Descriptor, bool Lazy,
1032 template <typename Type> class Allocator>
1033 template <typename Argument,
1035 (typename hash_table<Descriptor, Lazy, Allocator>::value_type *slot,
1038 hash_table<Descriptor, Lazy, Allocator>::traverse (Argument argument)
1040 if (too_empty_p (elements ()) && (!Lazy || m_entries))
1043 traverse_noresize <Argument, Callback> (argument);
1046 /* Slide down the iterator slots until an active entry is found. */
1048 template<typename Descriptor, bool Lazy,
1049 template<typename Type> class Allocator>
1051 hash_table<Descriptor, Lazy, Allocator>::iterator::slide ()
1053 for ( ; m_slot < m_limit; ++m_slot )
1055 value_type &x = *m_slot;
1056 if (!is_empty (x) && !is_deleted (x))
1063 /* Bump the iterator. */
1065 template<typename Descriptor, bool Lazy,
1066 template<typename Type> class Allocator>
1067 inline typename hash_table<Descriptor, Lazy, Allocator>::iterator &
1068 hash_table<Descriptor, Lazy, Allocator>::iterator::operator ++ ()
1076 /* Iterate through the elements of hash_table HTAB,
1077 using hash_table <....>::iterator ITER,
1078 storing each element in RESULT, which is of type TYPE. */
1080 #define FOR_EACH_HASH_TABLE_ELEMENT(HTAB, RESULT, TYPE, ITER) \
1081 for ((ITER) = (HTAB).begin (); \
1082 (ITER) != (HTAB).end () ? (RESULT = *(ITER) , true) : false; \
1085 /* ggc walking routines. */
1087 template<typename E>
1089 gt_ggc_mx (hash_table<E> *h)
1091 typedef hash_table<E> table;
1093 if (!ggc_test_and_set_mark (h->m_entries))
1096 for (size_t i = 0; i < h->m_size; i++)
1098 if (table::is_empty (h->m_entries[i])
1099 || table::is_deleted (h->m_entries[i]))
1102 /* Use ggc_maxbe_mx so we don't mark right away for cache tables; we'll
1103 mark in gt_cleare_cache if appropriate. */
1104 E::ggc_maybe_mx (h->m_entries[i]);
1108 template<typename D>
1110 hashtab_entry_note_pointers (void *obj, void *h, gt_pointer_operator op,
1113 hash_table<D> *map = static_cast<hash_table<D> *> (h);
1114 gcc_checking_assert (map->m_entries == obj);
1115 for (size_t i = 0; i < map->m_size; i++)
1117 typedef hash_table<D> table;
1118 if (table::is_empty (map->m_entries[i])
1119 || table::is_deleted (map->m_entries[i]))
1122 D::pch_nx (map->m_entries[i], op, cookie);
1126 template<typename D>
1128 gt_pch_nx (hash_table<D> *h)
1131 = gt_pch_note_object (h->m_entries, h, hashtab_entry_note_pointers<D>);
1132 gcc_checking_assert (success);
1133 for (size_t i = 0; i < h->m_size; i++)
1135 if (hash_table<D>::is_empty (h->m_entries[i])
1136 || hash_table<D>::is_deleted (h->m_entries[i]))
1139 D::pch_nx (h->m_entries[i]);
1143 template<typename D>
1145 gt_pch_nx (hash_table<D> *h, gt_pointer_operator op, void *cookie)
1147 op (&h->m_entries, cookie);
1150 template<typename H>
1152 gt_cleare_cache (hash_table<H> *h)
1154 typedef hash_table<H> table;
1158 for (typename table::iterator iter = h->begin (); iter != h->end (); ++iter)
1159 if (!table::is_empty (*iter) && !table::is_deleted (*iter))
1161 int res = H::keep_cache_entry (*iter);
1163 h->clear_slot (&*iter);
1169 #endif /* TYPED_HASHTAB_H */