1 | /* SparseSet implementation. |
2 | Copyright (C) 2007-2024 Free Software Foundation, Inc. |
3 | Contributed by Peter Bergner <bergner@vnet.ibm.com> |
4 | |
5 | This file is part of GCC. |
6 | |
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 |
10 | version. |
11 | |
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 |
15 | for more details. |
16 | |
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/>. */ |
20 | |
21 | #include "config.h" |
22 | #include "system.h" |
23 | #include "sparseset.h" |
24 | |
25 | /* Allocate and clear a n_elms SparseSet. */ |
26 | |
27 | sparseset |
28 | sparseset_alloc (SPARSESET_ELT_TYPE n_elms) |
29 | { |
30 | unsigned int n_bytes = sizeof (struct sparseset_def) |
31 | + ((n_elms - 1) * 2 * sizeof (SPARSESET_ELT_TYPE)); |
32 | |
33 | sparseset set = XNEWVAR (struct sparseset_def, n_bytes); |
34 | |
35 | /* Mark the sparseset as defined to silence some valgrind uninitialized |
36 | read errors when accessing set->sparse[n] when "n" is not, and never has |
37 | been, in the set. These uninitialized reads are expected, by design and |
38 | harmless. */ |
39 | VALGRIND_DISCARD (VALGRIND_MAKE_MEM_DEFINED (set, n_bytes)); |
40 | |
41 | set->dense = &(set->elms[0]); |
42 | set->sparse = &(set->elms[n_elms]); |
43 | set->size = n_elms; |
44 | sparseset_clear (s: set); |
45 | return set; |
46 | } |
47 | |
48 | /* Low level routine not meant for use outside of sparseset.[ch]. |
49 | Assumes idx1 < s->members and idx2 < s->members. */ |
50 | |
51 | static inline void |
52 | sparseset_swap (sparseset s, SPARSESET_ELT_TYPE idx1, SPARSESET_ELT_TYPE idx2) |
53 | { |
54 | SPARSESET_ELT_TYPE tmp = s->dense[idx2]; |
55 | sparseset_insert_bit (s, e: s->dense[idx1], idx: idx2); |
56 | sparseset_insert_bit (s, e: tmp, idx: idx1); |
57 | } |
58 | |
59 | /* Operation: S = S - {e} |
60 | Delete e from the set S if it is a member of S. */ |
61 | |
62 | void |
63 | sparseset_clear_bit (sparseset s, SPARSESET_ELT_TYPE e) |
64 | { |
65 | if (sparseset_bit_p (s, e)) |
66 | { |
67 | SPARSESET_ELT_TYPE idx = s->sparse[e]; |
68 | SPARSESET_ELT_TYPE iter = s->iter; |
69 | SPARSESET_ELT_TYPE mem = s->members - 1; |
70 | |
71 | /* If we are iterating over this set and we want to delete a |
72 | member we've already visited, then we swap the element we |
73 | want to delete with the element at the current iteration |
74 | index so that it plays well together with the code below |
75 | that actually removes the element. */ |
76 | if (s->iterating && idx <= iter) |
77 | { |
78 | if (idx < iter) |
79 | { |
80 | sparseset_swap (s, idx1: idx, idx2: iter); |
81 | idx = iter; |
82 | } |
83 | s->iter_inc = 0; |
84 | } |
85 | |
86 | /* Replace the element we want to delete with the last element |
87 | in the dense array and then decrement s->members, effectively |
88 | removing the element we want to delete. */ |
89 | sparseset_insert_bit (s, e: s->dense[mem], idx); |
90 | s->members = mem; |
91 | } |
92 | } |
93 | |
94 | /* Operation: D = S |
95 | Restrictions: none. */ |
96 | |
97 | void |
98 | sparseset_copy (sparseset d, sparseset s) |
99 | { |
100 | SPARSESET_ELT_TYPE i; |
101 | |
102 | if (d == s) |
103 | return; |
104 | |
105 | sparseset_clear (s: d); |
106 | for (i = 0; i < s->members; i++) |
107 | sparseset_insert_bit (s: d, e: s->dense[i], idx: i); |
108 | d->members = s->members; |
109 | } |
110 | |
111 | /* Operation: D = A & B. |
112 | Restrictions: none. */ |
113 | |
114 | void |
115 | sparseset_and (sparseset d, sparseset a, sparseset b) |
116 | { |
117 | SPARSESET_ELT_TYPE e; |
118 | |
119 | if (a == b) |
120 | { |
121 | if (d != a) |
122 | sparseset_copy (d, s: a); |
123 | return; |
124 | } |
125 | |
126 | if (d == a || d == b) |
127 | { |
128 | sparseset s = (d == a) ? b : a; |
129 | |
130 | EXECUTE_IF_SET_IN_SPARSESET (d, e) |
131 | if (!sparseset_bit_p (s, e)) |
132 | sparseset_clear_bit (s: d, e); |
133 | } |
134 | else |
135 | { |
136 | sparseset sml, lrg; |
137 | |
138 | if (sparseset_cardinality (s: a) < sparseset_cardinality (s: b)) |
139 | { |
140 | sml = a; |
141 | lrg = b; |
142 | } |
143 | else |
144 | { |
145 | sml = b; |
146 | lrg = a; |
147 | } |
148 | |
149 | sparseset_clear (s: d); |
150 | EXECUTE_IF_SET_IN_SPARSESET (sml, e) |
151 | if (sparseset_bit_p (s: lrg, e)) |
152 | sparseset_set_bit (s: d, e); |
153 | } |
154 | } |
155 | |
156 | /* Operation: D = A & ~B. |
157 | Restrictions: D != B, unless D == A == B. */ |
158 | |
159 | void |
160 | sparseset_and_compl (sparseset d, sparseset a, sparseset b) |
161 | { |
162 | SPARSESET_ELT_TYPE e; |
163 | |
164 | if (a == b) |
165 | { |
166 | sparseset_clear (s: d); |
167 | return; |
168 | } |
169 | |
170 | gcc_assert (d != b); |
171 | |
172 | if (d == a) |
173 | { |
174 | if (sparseset_cardinality (s: d) < sparseset_cardinality (s: b)) |
175 | { |
176 | EXECUTE_IF_SET_IN_SPARSESET (d, e) |
177 | if (sparseset_bit_p (s: b, e)) |
178 | sparseset_clear_bit (s: d, e); |
179 | } |
180 | else |
181 | { |
182 | EXECUTE_IF_SET_IN_SPARSESET (b, e) |
183 | sparseset_clear_bit (s: d, e); |
184 | } |
185 | } |
186 | else |
187 | { |
188 | sparseset_clear (s: d); |
189 | EXECUTE_IF_SET_IN_SPARSESET (a, e) |
190 | if (!sparseset_bit_p (s: b, e)) |
191 | sparseset_set_bit (s: d, e); |
192 | } |
193 | } |
194 | |
195 | /* Operation: D = A | B. |
196 | Restrictions: none. */ |
197 | |
198 | void |
199 | sparseset_ior (sparseset d, sparseset a, sparseset b) |
200 | { |
201 | SPARSESET_ELT_TYPE e; |
202 | |
203 | if (a == b) |
204 | sparseset_copy (d, s: a); |
205 | else if (d == b) |
206 | { |
207 | EXECUTE_IF_SET_IN_SPARSESET (a, e) |
208 | sparseset_set_bit (s: d, e); |
209 | } |
210 | else |
211 | { |
212 | if (d != a) |
213 | sparseset_copy (d, s: a); |
214 | EXECUTE_IF_SET_IN_SPARSESET (b, e) |
215 | sparseset_set_bit (s: d, e); |
216 | } |
217 | } |
218 | |
219 | /* Operation: A == B |
220 | Restrictions: none. */ |
221 | |
222 | bool |
223 | sparseset_equal_p (sparseset a, sparseset b) |
224 | { |
225 | SPARSESET_ELT_TYPE e; |
226 | |
227 | if (a == b) |
228 | return true; |
229 | |
230 | if (sparseset_cardinality (s: a) != sparseset_cardinality (s: b)) |
231 | return false; |
232 | |
233 | EXECUTE_IF_SET_IN_SPARSESET (a, e) |
234 | if (!sparseset_bit_p (s: b, e)) |
235 | return false; |
236 | |
237 | return true; |
238 | } |
239 | |
240 | |