+/* Binary relations.
+ Copyright (C) 2002 Free Software Foundation, Inc.
+
+ This file is part of Bison, the GNU Compiler Compiler.
+
+ Bison is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 2, or (at your option)
+ any later version.
+
+ Bison is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with Bison; see the file COPYING. If not, write to
+ the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ Boston, MA 02111-1307, USA. */
+
+#include "system.h"
+#include "bitsetv.h"
+#include "relation.h"
+#include "getargs.h"
+
+void
+relation_print (relation_t relation, size_t size, FILE *out)
+{
+ unsigned i, j;
+
+ for (i = 0; i < size; ++i)
+ {
+ fprintf (out, "%3d: ", i);
+ if (relation[i])
+ for (j = 0; relation[i][j] != -1; ++j)
+ fprintf (out, "%3d ", relation[i][j]);
+ fputc ('\n', out);
+ }
+ fputc ('\n', out);
+}
+
+
+/*---------------------------------------------------------------.
+| digraph & traverse. |
+| |
+| The following variables are used as common storage between the |
+| two. |
+`---------------------------------------------------------------*/
+
+static relation_t R;
+static relation_nodes_t INDEX;
+static relation_nodes_t VERTICES;
+static int top;
+static int infinity;
+static bitsetv F;
+
+static void
+traverse (int i)
+{
+ int j;
+ int height;
+
+ VERTICES[++top] = i;
+ INDEX[i] = height = top;
+
+ if (R[i])
+ for (j = 0; R[i][j] >= 0; ++j)
+ {
+ if (INDEX[R[i][j]] == 0)
+ traverse (R[i][j]);
+
+ if (INDEX[i] > INDEX[R[i][j]])
+ INDEX[i] = INDEX[R[i][j]];
+
+ bitset_or (F[i], F[i], F[R[i][j]]);
+ }
+
+ if (INDEX[i] == height)
+ for (;;)
+ {
+ j = VERTICES[top--];
+ INDEX[j] = infinity;
+
+ if (i == j)
+ break;
+
+ bitset_copy (F[j], F[i]);
+ }
+}
+
+
+void
+relation_digraph (relation_t relation, size_t size,
+ bitsetv *function)
+{
+ unsigned i;
+
+ infinity = size + 2;
+ INDEX = XCALLOC (relation_node_t, size + 1);
+ VERTICES = XCALLOC (relation_node_t, size + 1);
+ top = 0;
+
+ R = relation;
+ F = *function;
+
+ for (i = 0; i < size; i++)
+ INDEX[i] = 0;
+
+ for (i = 0; i < size; i++)
+ if (INDEX[i] == 0 && R[i])
+ traverse (i);
+
+ XFREE (INDEX);
+ XFREE (VERTICES);
+
+ *function = F;
+}
+
+
+/*-------------------------------------------.
+| Destructively transpose R_ARG, of size N. |
+`-------------------------------------------*/
+
+void
+relation_transpose (relation_t *R_arg, int n)
+{
+ /* The result. */
+ relation_t new_R = XCALLOC (relation_nodes_t, n);
+ /* END_R[I] -- next entry of NEW_R[I]. */
+ relation_t end_R = XCALLOC (relation_nodes_t, n);
+ /* NEDGES[I] -- total size of NEW_R[I]. */
+ int *nedges = XCALLOC (int, n);
+ int i, j;
+
+ if (trace_flag)
+ {
+ fputs ("relation_transpose: input\n", stderr);
+ relation_print (*R_arg, n, stderr);
+ }
+
+ /* Count. */
+ for (i = 0; i < n; i++)
+ if ((*R_arg)[i])
+ for (j = 0; (*R_arg)[i][j] >= 0; ++j)
+ ++nedges[(*R_arg)[i][j]];
+
+ /* Allocate. */
+ for (i = 0; i < n; i++)
+ if (nedges[i] > 0)
+ {
+ relation_node_t *sp = XCALLOC (relation_node_t, nedges[i] + 1);
+ sp[nedges[i]] = -1;
+ new_R[i] = sp;
+ end_R[i] = sp;
+ }
+
+ /* Store. */
+ for (i = 0; i < n; i++)
+ if ((*R_arg)[i])
+ for (j = 0; (*R_arg)[i][j] >= 0; ++j)
+ {
+ *end_R[(*R_arg)[i][j]] = i;
+ ++end_R[(*R_arg)[i][j]];
+ }
+
+ free (nedges);
+ free (end_R);
+
+ /* Free the input: it is replaced with the result. */
+ for (i = 0; i < n; i++)
+ XFREE ((*R_arg)[i]);
+ free (*R_arg);
+
+ if (trace_flag)
+ {
+ fputs ("relation_transpose: output\n", stderr);
+ relation_print (new_R, n, stderr);
+ }
+
+ *R_arg = new_R;
+}
projects / bison.git / commitdiff
