1 /* Binary relations.
2
3 Copyright (C) 2002, 2004-2005, 2009-2012 Free Software Foundation,
4 Inc.
5
6 This file is part of Bison, the GNU Compiler Compiler.
7
8 This program is free software: you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation, either version 3 of the License, or
11 (at your option) any later version.
12
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
17
18 You should have received a copy of the GNU General Public License
19 along with this program. If not, see <http://www.gnu.org/licenses/>. */
20
21 #include <config.h>
22 #include "system.h"
23
24 #include <bitsetv.h>
25
26 #include "getargs.h"
27 #include "relation.h"
28
29 void
relation_print(relation r,relation_node size,FILE * out)30 relation_print (relation r, relation_node size, FILE *out)
31 {
32 relation_node i;
33 relation_node j;
34
35 for (i = 0; i < size; ++i)
36 {
37 fprintf (out, "%3lu: ", (unsigned long int) i);
38 if (r[i])
39 for (j = 0; r[i][j] != END_NODE; ++j)
40 fprintf (out, "%3lu ", (unsigned long int) r[i][j]);
41 fputc ('\n', out);
42 }
43 fputc ('\n', out);
44 }
45
46
47 /*---------------------------------------------------------------.
48 | digraph & traverse. |
49 | |
50 | The following variables are used as common storage between the |
51 | two. |
52 `---------------------------------------------------------------*/
53
54 static relation R;
55 static relation_nodes INDEX;
56 static relation_nodes VERTICES;
57 static relation_node top;
58 static relation_node infinity;
59 static bitsetv F;
60
61 static void
traverse(relation_node i)62 traverse (relation_node i)
63 {
64 relation_node j;
65 relation_node height;
66
67 VERTICES[++top] = i;
68 INDEX[i] = height = top;
69
70 if (R[i])
71 for (j = 0; R[i][j] != END_NODE; ++j)
72 {
73 if (INDEX[R[i][j]] == 0)
74 traverse (R[i][j]);
75
76 if (INDEX[i] > INDEX[R[i][j]])
77 INDEX[i] = INDEX[R[i][j]];
78
79 bitset_or (F[i], F[i], F[R[i][j]]);
80 }
81
82 if (INDEX[i] == height)
83 for (;;)
84 {
85 j = VERTICES[top--];
86 INDEX[j] = infinity;
87
88 if (i == j)
89 break;
90
91 bitset_copy (F[j], F[i]);
92 }
93 }
94
95
96 void
relation_digraph(relation r,relation_node size,bitsetv * function)97 relation_digraph (relation r, relation_node size, bitsetv *function)
98 {
99 relation_node i;
100
101 infinity = size + 2;
102 INDEX = xcalloc (size + 1, sizeof *INDEX);
103 VERTICES = xnmalloc (size + 1, sizeof *VERTICES);
104 top = 0;
105
106 R = r;
107 F = *function;
108
109 for (i = 0; i < size; i++)
110 if (INDEX[i] == 0 && R[i])
111 traverse (i);
112
113 free (INDEX);
114 free (VERTICES);
115
116 *function = F;
117 }
118
119
120 /*-------------------------------------------.
121 | Destructively transpose R_ARG, of size N. |
122 `-------------------------------------------*/
123
124 void
relation_transpose(relation * R_arg,relation_node n)125 relation_transpose (relation *R_arg, relation_node n)
126 {
127 relation r = *R_arg;
128 /* The result. */
129 relation new_R = xnmalloc (n, sizeof *new_R);
130 /* END_R[I] -- next entry of NEW_R[I]. */
131 relation end_R = xnmalloc (n, sizeof *end_R);
132 /* NEDGES[I] -- total size of NEW_R[I]. */
133 size_t *nedges = xcalloc (n, sizeof *nedges);
134 relation_node i;
135 relation_node j;
136
137 if (trace_flag & trace_sets)
138 {
139 fputs ("relation_transpose: input\n", stderr);
140 relation_print (r, n, stderr);
141 }
142
143 /* Count. */
144 for (i = 0; i < n; i++)
145 if (r[i])
146 for (j = 0; r[i][j] != END_NODE; ++j)
147 ++nedges[r[i][j]];
148
149 /* Allocate. */
150 for (i = 0; i < n; i++)
151 {
152 relation_node *sp = NULL;
153 if (nedges[i] > 0)
154 {
155 sp = xnmalloc (nedges[i] + 1, sizeof *sp);
156 sp[nedges[i]] = END_NODE;
157 }
158 new_R[i] = sp;
159 end_R[i] = sp;
160 }
161
162 /* Store. */
163 for (i = 0; i < n; i++)
164 if (r[i])
165 for (j = 0; r[i][j] != END_NODE; ++j)
166 *end_R[r[i][j]]++ = i;
167
168 free (nedges);
169 free (end_R);
170
171 /* Free the input: it is replaced with the result. */
172 for (i = 0; i < n; i++)
173 free (r[i]);
174 free (r);
175
176 if (trace_flag & trace_sets)
177 {
178 fputs ("relation_transpose: output\n", stderr);
179 relation_print (new_R, n, stderr);
180 }
181
182 *R_arg = new_R;
183 }
184