nsz Git - libfirm/blob - ir/ana/dfs.c

   1 /*
   2  * Copyright (C) 1995-2007 University of Karlsruhe.  All right reserved.
   3  *
   4  * This file is part of libFirm.
   5  *
   6  * This file may be distributed and/or modified under the terms of the
   7  * GNU General Public License version 2 as published by the Free Software
   8  * Foundation and appearing in the file LICENSE.GPL included in the
   9  * packaging of this file.
  10  *
  11  * Licensees holding valid libFirm Professional Edition licenses may use
  12  * this file in accordance with the libFirm Commercial License.
  13  * Agreement provided with the Software.
  14  *
  15  * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
  16  * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  17  * PURPOSE.
  18  */
  19
  20 /**
  21  * @file    dfs.c
  22  * @author  Sebastian Hack
  23  * @date    20.04.2007
  24  * @version $Id$
  25  * @summary
  26  *
  27  * Simple depth first search on CFGs.
  28  */
  29 #include <assert.h>
  30 #include "irtools.h"
  31 #include "irprintf.h"
  32 #include "set.h"
  33 #include "dfs_t.h"
  34
  35 static int cmp_edge(const void *a, const void *b, size_t sz)
  36 {
  37         const dfs_edge_t *p = a;
  38         const dfs_edge_t *q = b;
  39
  40         return !(p->src == q->src && p->tgt == q->tgt);
  41 }
  42
  43 static int cmp_node(const void *a, const void *b, size_t sz)
  44 {
  45         const dfs_node_t *p = a;
  46         const dfs_node_t *q = b;
  47         return p->node != q->node;
  48 }
  49
  50 #define get_node(dfs, node) _dfs_get_node(dfs, node)
  51
  52 static dfs_edge_t *get_edge(const dfs_t *self, void *src, void *tgt)
  53 {
  54         unsigned hash = HASH_COMBINE(HASH_PTR(src), HASH_PTR(tgt));
  55         dfs_edge_t templ;
  56
  57         templ.src = src;
  58         templ.tgt = tgt;
  59         templ.kind = -1;
  60
  61         return set_insert(self->edges, &templ, sizeof(templ), hash);
  62 }
  63
  64 static void dfs_perform(dfs_t *dfs, void *n, void *anc)
  65 {
  66         dfs_node_t *node = get_node(dfs, n);
  67         void **succs, **iter;
  68
  69         assert(node->visited == 0);
  70
  71         node->visited     = 1;
  72         node->node        = n;
  73         node->ancestor    = anc;
  74         node->pre_num     = dfs->pre_num++;
  75         node->max_pre_num = node->pre_num;
  76
  77         dfs->graph_impl->grow_succs(dfs->graph, n, &dfs->obst);
  78         obstack_ptr_grow(&dfs->obst, NULL);
  79         succs = obstack_finish(&dfs->obst);
  80
  81         for (iter = succs; *iter; ++iter) {
  82                 void *p = *iter;
  83
  84                 /* get the node */
  85                 dfs_node_t *child = get_node(dfs, p);
  86
  87                 /* create the edge object */
  88                 dfs_edge_t *edge = get_edge(dfs, n, p);
  89                 edge->s = node;
  90                 edge->t = child;
  91
  92                 if (!child->visited)
  93                         dfs_perform(dfs, p, node);
  94
  95                 /* get the maximum pre num of the subtree. needed for ancestor determination. */
  96                 node->max_pre_num = MAX(node->max_pre_num, child->max_pre_num);
  97         }
  98
  99         node->post_num = dfs->post_num++;
 100         obstack_free(&dfs->obst, succs);
 101 }
 102
 103 static void classify_edges(dfs_t *dfs)
 104 {
 105         dfs_edge_t *edge;
 106
 107         foreach_set (dfs->edges, edge) {
 108                 dfs_node_t *src = edge->s;
 109                 dfs_node_t *tgt = edge->t;
 110
 111                 if (tgt->ancestor == src)
 112                         edge->kind = DFS_EDGE_ANC;
 113                 else if (_dfs_int_is_ancestor(tgt, src))
 114                         edge->kind = DFS_EDGE_BACK;
 115                 else if (_dfs_int_is_ancestor(src, tgt))
 116                         edge->kind = DFS_EDGE_FWD;
 117                 else
 118                         edge->kind = DFS_EDGE_CROSS;
 119         }
 120 }
 121
 122 dfs_edge_kind_t dfs_get_edge_kind(const dfs_t *dfs, void *a, void *b)
 123 {
 124         if (!dfs->edges_classified) {
 125                 dfs_t *urg = (dfs_t *) dfs;
 126                 classify_edges(urg);
 127                 urg->edges_classified = 1;
 128         }
 129         return get_edge(dfs, a, b)->kind;
 130 }
 131
 132 dfs_t *dfs_new(const absgraph_t *graph_impl, void *graph_self)
 133 {
 134         dfs_t *res = xmalloc(sizeof(res[0]));
 135         dfs_node_t *node;
 136
 137         res->graph_impl = graph_impl;
 138         res->graph      = graph_self;
 139         res->nodes      = new_set(cmp_node, 64);
 140         res->edges      = new_set(cmp_edge, 128);
 141
 142         res->pre_num  = 0;
 143         res->post_num = 0;
 144         res->edges_classified = 0;
 145
 146         obstack_init(&res->obst);
 147
 148         dfs_perform(res, graph_impl->get_root(graph_self), NULL);
 149         classify_edges(res);
 150
 151         res->pre_order = xmalloc(res->pre_num * sizeof(res->pre_order));
 152         res->post_order = xmalloc(res->pre_num * sizeof(res->post_order));
 153         foreach_set (res->nodes, node) {
 154                 res->pre_order[node->pre_num] = node;
 155                 res->post_order[node->post_num] = node;
 156         }
 157
 158         return res;
 159 }
 160
 161 void dfs_free(dfs_t *dfs)
 162 {
 163         del_set(dfs->nodes);
 164         del_set(dfs->edges);
 165         xfree(dfs->pre_order);
 166         xfree(dfs->post_order);
 167         xfree(dfs);
 168 }
 169
 170 void dfs_dump(const dfs_t *dfs, FILE *file)
 171 {
 172         dfs_node_t *node;
 173         dfs_edge_t *edge;
 174
 175         ir_fprintf(file, "digraph G {\n");
 176         foreach_set (dfs->nodes, node) {
 177                 ir_fprintf(file, "\tn%d [shape=box,label=\"%+F\\l%d/%d %d\"];\n",
 178                                 node->pre_num, node->node, node->pre_num, node->post_num, node->max_pre_num);
 179
 180         }
 181
 182         foreach_set (dfs->edges, edge) {
 183                 dfs_node_t *src = edge->s;
 184                 dfs_node_t *tgt = edge->t;
 185                 const char *s, *color;
 186
 187 #define XXX(e)          case DFS_EDGE_ ## e: s = #e; break
 188                 switch (edge->kind) {
 189                         XXX(BACK);
 190                         XXX(FWD);
 191                         XXX(CROSS);
 192                         XXX(ANC);
 193                         default:
 194                         s = "?";
 195                 }
 196 #undef XXX
 197
 198 #define XXX(e)  case DFS_EDGE_ ## e
 199                 switch (edge->kind) {
 200                         XXX(ANC):   color = "black"; break;
 201                         XXX(FWD):   color = "blue"; break;
 202                         XXX(CROSS): color = "red"; break;
 203                         XXX(BACK):  color = "darkviolet"; break;
 204                         default: color = "?";
 205                 }
 206 #undef XXX
 207
 208                 ir_fprintf(file, "\tn%d -> n%d [label=\"%s\",color=\"%s\"];\n", src->pre_num, tgt->pre_num, s, color);
 209         }
 210
 211         ir_fprintf(file, "}\n");
 212 }