1 /* A type-safe hash table template.
2 Copyright (C) 2012-2023 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).
38 Provided a suitable Descriptor class it may be a user-defined,
41 - A static member function named 'hash' that takes a value_type
42 (or 'const value_type &') and returns a hashval_t value.
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.
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
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).
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.
69 3. The type of the hash table itself. (More later.)
71 In very special circumstances, users may need to know about a fourth type.
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:
77 - A static member function named 'data_alloc'. This function
78 allocates the data elements in the table.
80 - A static member function named 'data_free'. This function
81 deallocates the data elements in the table.
83 Hash table are instantiated with two type arguments.
85 * The descriptor type, (2) above.
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.
92 DEFINING A DESCRIPTOR TYPE
94 The first task in using the hash table is to describe the element type.
95 We compose this into a few steps.
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
101 * typed_free_remove implements the static 'remove' member function
104 * typed_noop_remove implements the static 'remove' member function
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
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.
119 You can use these policies by simply deriving the descriptor type
120 from one of those class template, with the appropriate argument.
122 Otherwise, you need to write the static 'remove' member function
123 in the descriptor class.
125 2. Choose a hash function. Write the static 'hash' member function.
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
131 4. Choose an equality testing function 'equal' that compares a value_type
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
138 AN EXAMPLE DESCRIPTOR TYPE
140 Suppose you want to put some_type into the hash table. You could define
141 the descriptor type as follows.
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.
147 static inline hashval_t hash (const value_type *);
148 static inline bool equal (const value_type *, const compare_type *);
152 some_type_hasher::hash (const value_type *e)
153 { ... compute and return a hash value for E ... }
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' ... }
160 AN EXAMPLE HASH_TABLE DECLARATION
162 To instantiate a hash table for some_type:
164 hash_table <some_type_hasher> some_type_hash_table;
166 There is no need to mention some_type directly, as the hash table will
167 obtain it using some_type_hasher::value_type.
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
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
177 hash_table <some_type_hasher, true> some_type_hash_table;
179 which will cause whatever methods actually need the allocated entries
180 array to allocate it later.
183 EASY DESCRIPTORS FOR POINTERS
185 There are four descriptors for pointer elements, one for each of
186 the removal policies above:
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)
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:
197 hash_table <nofree_ptr_hash <whatever_type> > whatever_type_hash_table;
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:
205 extern void consume (some_info *);
207 We define a convenience typedef and the hash table:
209 typedef hash_table <some_info_hasher> info_table_type;
210 info_table_type info_table;
212 Then we write the loop in typical C++ style:
214 for (info_table_type::iterator iter = info_table.begin ();
215 iter != info_table.end ();
217 if ((*iter).status == INFO_READY)
220 Or with common sub-expression elimination:
222 for (info_table_type::iterator iter = info_table.begin ();
223 iter != info_table.end ();
226 some_info &elem = *iter;
227 if (elem.status == INFO_READY)
231 One can also use a more typical GCC style:
233 typedef some_info *some_info_p;
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)
243 #ifndef TYPED_HASHTAB_H
244 #define TYPED_HASHTAB_H
246 #include "statistics.h"
251 #include "mem-stats-traits.h"
252 #include "hash-traits.h"
253 #include "hash-map-traits.h"
255 template<typename
, typename
, typename
> class hash_map
;
256 template<typename
, bool, typename
> class hash_set
;
258 /* The ordinary memory allocator. */
259 /* FIXME (crowl): This allocator may be extracted for wider sharing later. */
261 template <typename Type
>
264 static Type
*data_alloc (size_t count
);
265 static void data_free (Type
*memory
);
269 /* Allocate memory for COUNT data blocks. */
271 template <typename Type
>
273 xcallocator
<Type
>::data_alloc (size_t count
)
275 return static_cast <Type
*> (xcalloc (count
, sizeof (Type
)));
279 /* Free memory for data blocks. */
281 template <typename Type
>
283 xcallocator
<Type
>::data_free (Type
*memory
)
285 return ::free (memory
);
289 /* Table of primes and their inversion information. */
295 hashval_t inv_m2
; /* inverse of prime-2 */
299 extern struct prime_ent
const prime_tab
[];
301 /* Limit number of comparisons when calling hash_table<>::verify. */
302 extern unsigned int hash_table_sanitize_eq_limit
;
304 /* Functions for computing hash table indexes. */
306 extern unsigned int hash_table_higher_prime_index (unsigned long n
)
309 extern ATTRIBUTE_NORETURN ATTRIBUTE_COLD
void hashtab_chk_error ();
311 /* Return X % Y using multiplicative inverse values INV and SHIFT.
313 The multiplicative inverses computed above are for 32-bit types,
314 and requires that we be able to compute a highpart multiply.
316 FIX: I am not at all convinced that
317 3 loads, 2 multiplications, 3 shifts, and 3 additions
320 on modern systems running a compiler. */
323 mul_mod (hashval_t x
, hashval_t y
, hashval_t inv
, int shift
)
325 hashval_t t1
, t2
, t3
, t4
, q
, r
;
327 t1
= ((uint64_t)x
* inv
) >> 32;
337 /* Compute the primary table index for HASH given current prime index. */
340 hash_table_mod1 (hashval_t hash
, unsigned int index
)
342 const struct prime_ent
*p
= &prime_tab
[index
];
343 gcc_checking_assert (sizeof (hashval_t
) * CHAR_BIT
<= 32);
344 return mul_mod (hash
, p
->prime
, p
->inv
, p
->shift
);
347 /* Compute the secondary table index for HASH given current prime index. */
350 hash_table_mod2 (hashval_t hash
, unsigned int index
)
352 const struct prime_ent
*p
= &prime_tab
[index
];
353 gcc_checking_assert (sizeof (hashval_t
) * CHAR_BIT
<= 32);
354 return 1 + mul_mod (hash
, p
->prime
- 2, p
->inv_m2
, p
->shift
);
359 /* User-facing hash table type.
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.
365 Specify the template Allocator to allocate and free memory.
366 The default is xcallocator.
368 Storage is an implementation detail and should not be used outside the
372 template <typename Descriptor
, bool Lazy
= false,
373 template<typename Type
> class Allocator
= xcallocator
>
376 typedef typename
Descriptor::value_type value_type
;
377 typedef typename
Descriptor::compare_type compare_type
;
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
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
392 /* Create a hash_table in gc memory. */
394 create_ggc (size_t n
, bool sanitize_eq_and_hash
= true CXX_MEM_STAT_INFO
)
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
);
402 /* Current size (in entries) of the hash table. */
403 size_t size () const { return m_size
; }
405 /* Return the current number of elements in this hash table. */
406 size_t elements () const { return m_n_elements
- m_n_deleted
; }
408 /* Return the current number of elements in this hash table. */
409 size_t elements_with_deleted () const { return m_n_elements
; }
411 /* This function clears all entries in this hash table. */
412 void empty () { if (elements ()) empty_slow (); }
414 /* Return true when there are no elements in this hash table. */
415 bool is_empty () const { return elements () == 0; }
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
420 void clear_slot (value_type
*);
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
);
427 /* Like find_slot_with_hash, but compute the hash value from the element. */
428 value_type
&find (const value_type
&value
)
430 return find_with_hash (value
, Descriptor::hash (value
));
433 value_type
*find_slot (const value_type
&value
, insert_option insert
)
435 return find_slot_with_hash (value
, Descriptor::hash (value
), insert
);
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
);
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
);
453 /* Like remove_elt_with_hash, but compute the hash value from the
455 void remove_elt (const value_type
&value
)
457 remove_elt_with_hash (value
, Descriptor::hash (value
));
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
);
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
);
476 iterator () : m_slot (NULL
), m_limit (NULL
) {}
478 iterator (value_type
*slot
, value_type
*limit
) :
479 m_slot (slot
), m_limit (limit
) {}
481 inline value_type
&operator * () { return *m_slot
; }
483 inline iterator
&operator ++ ();
484 bool operator != (const iterator
&other
) const
486 return m_slot
!= other
.m_slot
|| m_limit
!= other
.m_limit
;
494 iterator
begin () const
496 if (Lazy
&& m_entries
== NULL
)
498 check_complete_insertion ();
499 iterator
iter (m_entries
, m_entries
+ m_size
);
504 iterator
end () const { return iterator (); }
506 double collisions () const
508 return m_searches
? static_cast <double> (m_collisions
) / m_searches
: 0;
512 /* FIXME: Make the class assignable. See pr90959. */
513 void operator= (hash_table
&);
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 *);
526 template<typename T
> friend void gt_cleare_cache (hash_table
<T
> *);
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);
535 static bool is_deleted (value_type
&v
)
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
);
545 static bool is_empty (value_type
&v
)
547 return Descriptor::is_empty (v
);
550 static void mark_deleted (value_type
&v
)
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
));
560 static void mark_empty (value_type
&v
)
562 Descriptor::mark_empty (v
);
566 void check_complete_insertion () const
569 if (!m_inserting_slot
)
572 gcc_checking_assert (m_inserting_slot
>= &m_entries
[0]
573 && m_inserting_slot
< &m_entries
[m_size
]);
575 if (!is_empty (*m_inserting_slot
))
576 m_inserting_slot
= NULL
;
583 value_type
*check_insert_slot (value_type
*ret
)
586 gcc_checking_assert (is_empty (*ret
));
587 m_inserting_slot
= ret
;
593 mutable value_type
*m_inserting_slot
;
597 value_type
*m_entries
;
601 /* Current number of elements including also deleted elements. */
604 /* Current number of deleted elements in the table. */
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
;
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
;
615 /* Current size (in entries) of the hash table, as an index into the
617 unsigned int m_size_prime_index
;
619 /* if m_entries is stored in ggc memory. */
622 /* True if the table should be sanitized for equal and hash functions. */
623 bool m_sanitize_eq_and_hash
;
625 /* If we should gather memory statistics for the table. */
626 #if GATHER_STATISTICS
627 bool m_gather_mem_stats
;
629 static const bool m_gather_mem_stats
= false;
633 /* As mem-stats.h heavily utilizes hash maps (hash tables), we have to include
634 mem-stats.h after hash_table declaration. */
636 #include "mem-stats.h"
637 #include "hash-map.h"
639 extern mem_alloc_description
<mem_usage
>& hash_table_usage (void);
641 /* Support function for statistics. */
642 extern void dump_hash_table_loc_statistics (void);
644 template<typename Descriptor
, bool Lazy
,
645 template<typename Type
> class Allocator
>
646 hash_table
<Descriptor
, Lazy
, Allocator
>::hash_table (size_t size
, bool ggc
,
647 bool sanitize_eq_and_hash
,
648 bool gather_mem_stats
650 mem_alloc_origin origin
653 m_inserting_slot (0),
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
)
661 unsigned int size_prime_index
;
663 size_prime_index
= hash_table_higher_prime_index (size
);
664 size
= prime_tab
[size_prime_index
].prime
;
666 if (m_gather_mem_stats
)
667 hash_table_usage ().register_descriptor (this, origin
, ggc
668 FINAL_PASS_MEM_STAT
);
673 m_entries
= alloc_entries (size PASS_MEM_STAT
);
675 m_size_prime_index
= size_prime_index
;
678 template<typename Descriptor
, bool Lazy
,
679 template<typename Type
> class Allocator
>
680 hash_table
<Descriptor
, Lazy
, Allocator
>::hash_table (const hash_table
&h
,
682 bool sanitize_eq_and_hash
,
683 bool gather_mem_stats
685 mem_alloc_origin origin
688 m_inserting_slot (0),
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
)
697 h
.check_complete_insertion ();
699 size_t size
= h
.m_size
;
701 if (m_gather_mem_stats
)
702 hash_table_usage ().register_descriptor (this, origin
, ggc
703 FINAL_PASS_MEM_STAT
);
705 if (Lazy
&& h
.m_entries
== NULL
)
709 value_type
*nentries
= alloc_entries (size PASS_MEM_STAT
);
710 for (size_t i
= 0; i
< size
; ++i
)
712 value_type
&entry
= h
.m_entries
[i
];
713 if (is_empty (entry
))
715 else if (is_deleted (entry
))
716 mark_deleted (nentries
[i
]);
718 new ((void*) (nentries
+ i
)) value_type (entry
);
720 m_entries
= nentries
;
723 m_size_prime_index
= h
.m_size_prime_index
;
726 template<typename Descriptor
, bool Lazy
,
727 template<typename Type
> class Allocator
>
728 hash_table
<Descriptor
, Lazy
, Allocator
>::~hash_table ()
730 check_complete_insertion ();
732 if (!Lazy
|| m_entries
)
734 for (size_t i
= m_size
- 1; i
< m_size
; i
--)
735 if (!is_empty (m_entries
[i
]) && !is_deleted (m_entries
[i
]))
736 Descriptor::remove (m_entries
[i
]);
739 Allocator
<value_type
> ::data_free (m_entries
);
741 ggc_free (m_entries
);
742 if (m_gather_mem_stats
)
743 hash_table_usage ().release_instance_overhead (this,
747 else if (m_gather_mem_stats
)
748 hash_table_usage ().unregister_descriptor (this);
751 /* This function returns an array of empty hash table elements. */
753 template<typename Descriptor
, bool Lazy
,
754 template<typename Type
> class Allocator
>
755 inline typename hash_table
<Descriptor
, Lazy
, Allocator
>::value_type
*
756 hash_table
<Descriptor
, Lazy
,
757 Allocator
>::alloc_entries (size_t n MEM_STAT_DECL
) const
759 value_type
*nentries
;
761 if (m_gather_mem_stats
)
762 hash_table_usage ().register_instance_overhead (sizeof (value_type
) * n
, this);
765 nentries
= Allocator
<value_type
> ::data_alloc (n
);
767 nentries
= ::ggc_cleared_vec_alloc
<value_type
> (n PASS_MEM_STAT
);
769 gcc_assert (nentries
!= NULL
);
770 if (!Descriptor::empty_zero_p
)
771 for (size_t i
= 0; i
< n
; i
++)
772 mark_empty (nentries
[i
]);
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
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. */
784 template<typename Descriptor
, bool Lazy
,
785 template<typename Type
> class Allocator
>
786 typename hash_table
<Descriptor
, Lazy
, Allocator
>::value_type
*
787 hash_table
<Descriptor
, Lazy
,
788 Allocator
>::find_empty_slot_for_expand (hashval_t hash
)
790 hashval_t index
= hash_table_mod1 (hash
, m_size_prime_index
);
791 size_t size
= m_size
;
792 value_type
*slot
= m_entries
+ index
;
795 if (is_empty (*slot
))
797 gcc_checking_assert (!is_deleted (*slot
));
799 hash2
= hash_table_mod2 (hash
, m_size_prime_index
);
806 slot
= m_entries
+ index
;
807 if (is_empty (*slot
))
809 gcc_checking_assert (!is_deleted (*slot
));
813 /* Return true if the current table is excessively big for ELTS elements. */
815 template<typename Descriptor
, bool Lazy
,
816 template<typename Type
> class Allocator
>
818 hash_table
<Descriptor
, Lazy
, Allocator
>::too_empty_p (unsigned int elts
)
820 return elts
* 8 < m_size
&& m_size
> 32;
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
830 template<typename Descriptor
, bool Lazy
,
831 template<typename Type
> class Allocator
>
833 hash_table
<Descriptor
, Lazy
, Allocator
>::expand ()
835 check_complete_insertion ();
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 ();
843 /* Resize only when table after removal of unused elements is either
844 too full or too empty. */
847 if (elts
* 2 > osize
|| too_empty_p (elts
))
849 nindex
= hash_table_higher_prime_index (elts
* 2);
850 nsize
= prime_tab
[nindex
].prime
;
858 value_type
*nentries
= alloc_entries (nsize
);
860 if (m_gather_mem_stats
)
861 hash_table_usage ().release_instance_overhead (this, sizeof (value_type
)
864 size_t n_deleted
= m_n_deleted
;
866 m_entries
= nentries
;
868 m_size_prime_index
= nindex
;
869 m_n_elements
-= m_n_deleted
;
872 size_t n_elements
= m_n_elements
;
874 value_type
*p
= oentries
;
881 else if (is_deleted (x
))
886 value_type
*q
= find_empty_slot_for_expand (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. */
897 gcc_checking_assert (!n_elements
&& !n_deleted
);
900 Allocator
<value_type
> ::data_free (oentries
);
905 /* Implements empty() in cases where it isn't a no-op. */
907 template<typename Descriptor
, bool Lazy
,
908 template<typename Type
> class Allocator
>
910 hash_table
<Descriptor
, Lazy
, Allocator
>::empty_slow ()
912 check_complete_insertion ();
914 size_t size
= m_size
;
916 value_type
*entries
= m_entries
;
918 for (size_t i
= size
- 1; i
< size
; i
--)
919 if (!is_empty (entries
[i
]) && !is_deleted (entries
[i
]))
920 Descriptor::remove (entries
[i
]);
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 (m_n_elements
))
926 nsize
= m_n_elements
* 2;
930 unsigned int nindex
= hash_table_higher_prime_index (nsize
);
932 nsize
= prime_tab
[nindex
].prime
;
935 Allocator
<value_type
> ::data_free (m_entries
);
937 ggc_free (m_entries
);
939 m_entries
= alloc_entries (nsize
);
941 m_size_prime_index
= nindex
;
943 else if (Descriptor::empty_zero_p
)
944 memset ((void *) entries
, 0, size
* sizeof (value_type
));
946 for (size_t i
= 0; i
< size
; i
++)
947 mark_empty (entries
[i
]);
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
957 template<typename Descriptor
, bool Lazy
,
958 template<typename Type
> class Allocator
>
960 hash_table
<Descriptor
, Lazy
, Allocator
>::clear_slot (value_type
*slot
)
962 check_complete_insertion ();
964 gcc_checking_assert (!(slot
< m_entries
|| slot
>= m_entries
+ size ()
965 || is_empty (*slot
) || is_deleted (*slot
)));
967 Descriptor::remove (*slot
);
969 mark_deleted (*slot
);
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. */
977 template<typename Descriptor
, bool Lazy
,
978 template<typename Type
> class Allocator
>
979 typename hash_table
<Descriptor
, Lazy
, Allocator
>::value_type
&
980 hash_table
<Descriptor
, Lazy
, Allocator
>
981 ::find_with_hash (const compare_type
&comparable
, hashval_t hash
)
984 size_t size
= m_size
;
985 hashval_t index
= hash_table_mod1 (hash
, m_size_prime_index
);
987 if (Lazy
&& m_entries
== NULL
)
988 m_entries
= alloc_entries (size
);
990 check_complete_insertion ();
993 if (m_sanitize_eq_and_hash
)
994 verify (comparable
, hash
);
997 value_type
*entry
= &m_entries
[index
];
998 if (is_empty (*entry
)
999 || (!is_deleted (*entry
) && Descriptor::equal (*entry
, comparable
)))
1002 hashval_t hash2
= hash_table_mod2 (hash
, m_size_prime_index
);
1010 entry
= &m_entries
[index
];
1011 if (is_empty (*entry
)
1012 || (!is_deleted (*entry
) && Descriptor::equal (*entry
, comparable
)))
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. */
1025 template<typename Descriptor
, bool Lazy
,
1026 template<typename Type
> class Allocator
>
1027 typename hash_table
<Descriptor
, Lazy
, Allocator
>::value_type
*
1028 hash_table
<Descriptor
, Lazy
, Allocator
>
1029 ::find_slot_with_hash (const compare_type
&comparable
, hashval_t hash
,
1030 enum insert_option insert
)
1032 if (Lazy
&& m_entries
== NULL
)
1034 if (insert
== INSERT
)
1035 m_entries
= alloc_entries (m_size
);
1039 if (insert
== INSERT
&& m_size
* 3 <= m_n_elements
* 4)
1042 check_complete_insertion ();
1045 if (m_sanitize_eq_and_hash
)
1046 verify (comparable
, hash
);
1050 value_type
*first_deleted_slot
= NULL
;
1051 hashval_t index
= hash_table_mod1 (hash
, m_size_prime_index
);
1052 hashval_t hash2
= hash_table_mod2 (hash
, m_size_prime_index
);
1053 value_type
*entry
= &m_entries
[index
];
1054 size_t size
= m_size
;
1055 if (is_empty (*entry
))
1057 else if (is_deleted (*entry
))
1058 first_deleted_slot
= &m_entries
[index
];
1059 else if (Descriptor::equal (*entry
, comparable
))
1060 return &m_entries
[index
];
1069 entry
= &m_entries
[index
];
1070 if (is_empty (*entry
))
1072 else if (is_deleted (*entry
))
1074 if (!first_deleted_slot
)
1075 first_deleted_slot
= &m_entries
[index
];
1077 else if (Descriptor::equal (*entry
, comparable
))
1078 return &m_entries
[index
];
1082 if (insert
== NO_INSERT
)
1085 if (first_deleted_slot
)
1088 mark_empty (*first_deleted_slot
);
1089 return check_insert_slot (first_deleted_slot
);
1093 return check_insert_slot (&m_entries
[index
]);
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. */
1100 template<typename Descriptor
, bool Lazy
,
1101 template<typename Type
> class Allocator
>
1103 hash_table
<Descriptor
, Lazy
, Allocator
>
1104 ::verify (const compare_type
&comparable
, hashval_t hash
)
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
++)
1110 value_type
*entry
= &m_entries
[i
];
1111 if (!is_empty (*entry
))
1114 if (is_deleted (*entry
))
1116 else if (hash
!= Descriptor::hash (*entry
)
1117 && Descriptor::equal (*entry
, comparable
))
1118 hashtab_chk_error ();
1121 if (hash_table_sanitize_eq_limit
>= m_size
)
1122 gcc_checking_assert (!n_elements
&& !n_deleted
);
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. */
1129 template<typename Descriptor
, bool Lazy
,
1130 template<typename Type
> class Allocator
>
1132 hash_table
<Descriptor
, Lazy
, Allocator
>
1133 ::remove_elt_with_hash (const compare_type
&comparable
, hashval_t hash
)
1135 check_complete_insertion ();
1137 value_type
*slot
= find_slot_with_hash (comparable
, hash
, NO_INSERT
);
1141 Descriptor::remove (*slot
);
1143 mark_deleted (*slot
);
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. */
1151 template<typename Descriptor
, bool Lazy
,
1152 template<typename Type
> class Allocator
>
1153 template<typename Argument
,
1155 (typename hash_table
<Descriptor
, Lazy
, Allocator
>::value_type
*slot
,
1158 hash_table
<Descriptor
, Lazy
, Allocator
>::traverse_noresize (Argument argument
)
1160 if (Lazy
&& m_entries
== NULL
)
1163 check_complete_insertion ();
1165 value_type
*slot
= m_entries
;
1166 value_type
*limit
= slot
+ size ();
1170 value_type
&x
= *slot
;
1172 if (!is_empty (x
) && !is_deleted (x
))
1173 if (! Callback (slot
, argument
))
1176 while (++slot
< limit
);
1179 /* Like traverse_noresize, but does resize the table when it is too empty
1180 to improve effectivity of subsequent calls. */
1182 template <typename Descriptor
, bool Lazy
,
1183 template <typename Type
> class Allocator
>
1184 template <typename Argument
,
1186 (typename hash_table
<Descriptor
, Lazy
, Allocator
>::value_type
*slot
,
1189 hash_table
<Descriptor
, Lazy
, Allocator
>::traverse (Argument argument
)
1191 if (too_empty_p (elements ()) && (!Lazy
|| m_entries
))
1194 traverse_noresize
<Argument
, Callback
> (argument
);
1197 /* Slide down the iterator slots until an active entry is found. */
1199 template<typename Descriptor
, bool Lazy
,
1200 template<typename Type
> class Allocator
>
1202 hash_table
<Descriptor
, Lazy
, Allocator
>::iterator::slide ()
1204 for ( ; m_slot
< m_limit
; ++m_slot
)
1206 value_type
&x
= *m_slot
;
1207 if (!is_empty (x
) && !is_deleted (x
))
1214 /* Bump the iterator. */
1216 template<typename Descriptor
, bool Lazy
,
1217 template<typename Type
> class Allocator
>
1218 inline typename hash_table
<Descriptor
, Lazy
, Allocator
>::iterator
&
1219 hash_table
<Descriptor
, Lazy
, Allocator
>::iterator::operator ++ ()
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. */
1231 #define FOR_EACH_HASH_TABLE_ELEMENT(HTAB, RESULT, TYPE, ITER) \
1232 for ((ITER) = (HTAB).begin (); \
1233 (ITER) != (HTAB).end () ? (RESULT = *(ITER) , true) : false; \
1236 /* ggc walking routines. */
1238 template<typename E
>
1240 gt_ggc_mx (hash_table
<E
> *h
)
1242 typedef hash_table
<E
> table
;
1244 if (!ggc_test_and_set_mark (h
->m_entries
))
1247 for (size_t i
= 0; i
< h
->m_size
; i
++)
1249 if (table::is_empty (h
->m_entries
[i
])
1250 || table::is_deleted (h
->m_entries
[i
]))
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
]);
1259 template<typename D
>
1261 hashtab_entry_note_pointers (void *obj
, void *h
, gt_pointer_operator op
,
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
++)
1268 typedef hash_table
<D
> table
;
1269 if (table::is_empty (map
->m_entries
[i
])
1270 || table::is_deleted (map
->m_entries
[i
]))
1273 D::pch_nx (map
->m_entries
[i
], op
, cookie
);
1277 template<typename D
>
1279 gt_pch_nx (hash_table
<D
> *h
)
1281 h
->check_complete_insertion ();
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
++)
1287 if (hash_table
<D
>::is_empty (h
->m_entries
[i
])
1288 || hash_table
<D
>::is_deleted (h
->m_entries
[i
]))
1291 D::pch_nx (h
->m_entries
[i
]);
1295 template<typename D
>
1297 gt_pch_nx (hash_table
<D
> *h
, gt_pointer_operator op
, void *cookie
)
1299 op (&h
->m_entries
, NULL
, cookie
);
1302 template<typename H
>
1304 gt_cleare_cache (hash_table
<H
> *h
)
1306 typedef hash_table
<H
> table
;
1310 for (typename
table::iterator iter
= h
->begin (); iter
!= h
->end (); ++iter
)
1311 if (!table::is_empty (*iter
) && !table::is_deleted (*iter
))
1313 int res
= H::keep_cache_entry (*iter
);
1315 h
->clear_slot (&*iter
);
1321 #endif /* TYPED_HASHTAB_H */