1 /* objc-map.c -- Implementation of map data structures for ObjC compiler
2 Copyright (C) 2011-2016 Free Software Foundation, Inc.
3 Written by Nicola Pero <nicola.pero@meta-innovation.com>
4
5 This program is free software; you can redistribute it and/or modify it
6 under the terms of the GNU Lesser Public License as published by the
7 Free Software Foundation; either version 3, or (at your option) any
8 later version.
9
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU Lesser Public License for more details.
14
15 You should have received a copy of the GNU Lesser Public License
16 along with this program; if not, write to the Free Software
17 Foundation, 51 Franklin Street - Fifth Floor,
18 Boston, MA 02110-1301, USA. */
19
20 #include "config.h"
21 #include "system.h"
22 #include "coretypes.h"
23 #include "tree.h"
24 #include "objc-map.h"
25
26 #define OUT_OF_MEMORY { fprintf (stderr, "Out of memory\n"); abort (); }
27
28 static
29 size_t
30 ATTRIBUTE_PURE
next_power_of_two(size_t x)31 next_power_of_two (size_t x)
32 {
33 size_t result = 1;
34
35 if (x < 2)
36 return 2;
37
38 /* Avoid the long calculation if x is already a power of two. Since
39 we internally always increase/shrink tables by powers of 2, the
40 calculation should only be done once, when the table is first
41 set up. */
42 if ((x & (x - 1)) == 0)
43 return x;
44
45 /* Calculate log_2 by counting how many times we can divide by 2
46 before reaching 0. */
47 while (x > 0)
48 {
49 x = x >> 1;
50 result = result << 1;
51 }
52 return result;
53 }
54
55 objc_map_t
objc_map_alloc_ggc(size_t initial_capacity)56 objc_map_alloc_ggc (size_t initial_capacity)
57 {
58 objc_map_t map = ggc_cleared_alloc<objc_map_private> ();
59 if (map == NULL)
60 OUT_OF_MEMORY;
61
62 initial_capacity = next_power_of_two (initial_capacity);
63
64 map->number_of_slots = initial_capacity;
65 map->mask = initial_capacity - 1;
66 map->maximum_load_factor = 70;
67 map->max_number_of_non_empty_slots = (initial_capacity * map->maximum_load_factor) / 100;
68
69 map->slots = ggc_cleared_vec_alloc<tree> (initial_capacity);
70 map->values = ggc_cleared_vec_alloc<tree> (initial_capacity);
71
72 if (map->slots == NULL)
73 OUT_OF_MEMORY;
74
75 if (map->values == NULL)
76 OUT_OF_MEMORY;
77
78 return map;
79 }
80
81 void
objc_map_set_maximum_load_factor(objc_map_t map,int number_between_zero_and_one_hundred)82 objc_map_set_maximum_load_factor (objc_map_t map, int number_between_zero_and_one_hundred)
83 {
84 if (map->number_of_non_empty_slots != 0)
85 return;
86
87 map->maximum_load_factor = number_between_zero_and_one_hundred;
88 map->max_number_of_non_empty_slots = (map->number_of_slots * number_between_zero_and_one_hundred) / 100;
89 }
90
91 int
objc_map_maximum_load_factor(objc_map_t map)92 objc_map_maximum_load_factor (objc_map_t map)
93 {
94 return map->maximum_load_factor;
95 }
96
97 static void
objc_map_private_resize(objc_map_t map,size_t new_number_of_slots)98 objc_map_private_resize (objc_map_t map, size_t new_number_of_slots)
99 {
100 tree *old_slots = map->slots;
101 tree *old_values = map->values;
102 size_t i, old_number_of_slots = map->number_of_slots;
103
104 if (new_number_of_slots < (map->number_of_non_empty_slots))
105 new_number_of_slots = 2 * map->number_of_non_empty_slots;
106
107 new_number_of_slots = next_power_of_two (new_number_of_slots);
108
109 map->number_of_slots = new_number_of_slots;
110 map->mask = map->number_of_slots - 1;
111 map->max_number_of_non_empty_slots = (map->number_of_slots * map->maximum_load_factor) / 100;
112
113
114 map->slots = ggc_cleared_vec_alloc<tree> (map->number_of_slots);
115 map->values = ggc_cleared_vec_alloc<tree> (map->number_of_slots);
116
117 if (map->slots == NULL)
118 OUT_OF_MEMORY;
119
120 if (map->values == NULL)
121 OUT_OF_MEMORY;
122
123 for (i = 0; i < old_number_of_slots; i++)
124 if (old_slots[i] != OBJC_MAP_PRIVATE_EMPTY_SLOT)
125 {
126 size_t k = IDENTIFIER_HASH_VALUE (old_slots[i]) & map->mask;
127
128 if (map->slots[k] == OBJC_MAP_PRIVATE_EMPTY_SLOT)
129 {
130 map->slots[k] = old_slots[i];
131 map->values[k] = old_values[i];
132 }
133 else
134 {
135 size_t j = 1;
136 while (1)
137 {
138 k = (k + j) & map->mask;
139 if (map->slots[k] == OBJC_MAP_PRIVATE_EMPTY_SLOT)
140 {
141 map->slots[k] = old_slots[i];
142 map->values[k] = old_values[i];
143 break;
144 }
145 j++;
146 }
147 }
148 }
149
150 ggc_free (old_slots);
151 ggc_free (old_values);
152 }
153
154 void
objc_map_private_grow(struct objc_map_private * map)155 objc_map_private_grow (struct objc_map_private *map)
156 {
157 objc_map_private_resize (map, map->number_of_slots * 2);
158 }
159
160 #include "gt-objc-objc-map.h"
161