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         (void) sz;
  40
  41         return !(p->src == q->src && p->tgt == q->tgt);
  42 }
  43
  44 static int cmp_node(const void *a, const void *b, size_t sz)
  45 {
  46         const dfs_node_t *p = a;
  47         const dfs_node_t *q = b;
  48         (void) sz;
  49
  50         return p->node != q->node;
  51 }
  52
  53 #define get_node(dfs, node) _dfs_get_node(dfs, node)
  54
  55 static dfs_edge_t *get_edge(const dfs_t *self, void *src, void *tgt)
  56 {
  57         unsigned hash = HASH_COMBINE(HASH_PTR(src), HASH_PTR(tgt));
  58         dfs_edge_t templ;
  59
  60         templ.src = src;
  61         templ.tgt = tgt;
  62         templ.kind = -1;
  63
  64         return set_insert(self->edges, &templ, sizeof(templ), hash);
  65 }
  66
  67 static void dfs_perform(dfs_t *dfs, void *n, void *anc)
  68 {
  69         dfs_node_t *node = get_node(dfs, n);
  70         void **succs, **iter;
  71
  72         assert(node->visited == 0);
  73
  74         node->visited     = 1;
  75         node->node        = n;
  76         node->ancestor    = anc;
  77         node->pre_num     = dfs->pre_num++;
  78         node->max_pre_num = node->pre_num;
  79
  80         dfs->graph_impl->grow_succs(dfs->graph, n, &dfs->obst);
  81         obstack_ptr_grow(&dfs->obst, NULL);
  82         succs = obstack_finish(&dfs->obst);
  83
  84         for (iter = succs; *iter; ++iter) {
  85                 void *p = *iter;
  86
  87                 /* get the node */
  88                 dfs_node_t *child = get_node(dfs, p);
  89
  90                 /* create the edge object */
  91                 dfs_edge_t *edge = get_edge(dfs, n, p);
  92                 edge->s = node;
  93                 edge->t = child;
  94
  95                 if (!child->visited)
  96                         dfs_perform(dfs, p, node);
  97
  98                 /* get the maximum pre num of the subtree. needed for ancestor determination. */
  99                 node->max_pre_num = MAX(node->max_pre_num, child->max_pre_num);
 100         }
 101
 102         node->post_num = dfs->post_num++;
 103         obstack_free(&dfs->obst, succs);
 104 }
 105
 106 static void classify_edges(dfs_t *dfs)
 107 {
 108         dfs_edge_t *edge;
 109
 110         foreach_set (dfs->edges, edge) {
 111                 dfs_node_t *src = edge->s;
 112                 dfs_node_t *tgt = edge->t;
 113
 114                 if (tgt->ancestor == src)
 115                         edge->kind = DFS_EDGE_ANC;
 116                 else if (_dfs_int_is_ancestor(tgt, src))
 117                         edge->kind = DFS_EDGE_BACK;
 118                 else if (_dfs_int_is_ancestor(src, tgt))
 119                         edge->kind = DFS_EDGE_FWD;
 120                 else
 121                         edge->kind = DFS_EDGE_CROSS;
 122         }
 123 }
 124
 125 dfs_edge_kind_t dfs_get_edge_kind(const dfs_t *dfs, void *a, void *b)
 126 {
 127         if (!dfs->edges_classified) {
 128                 dfs_t *urg = (dfs_t *) dfs;
 129                 classify_edges(urg);
 130                 urg->edges_classified = 1;
 131         }
 132         return get_edge(dfs, a, b)->kind;
 133 }
 134
 135 dfs_t *dfs_new(const absgraph_t *graph_impl, void *graph_self)
 136 {
 137         dfs_t *res = xmalloc(sizeof(res[0]));
 138         dfs_node_t *node;
 139
 140         res->graph_impl = graph_impl;
 141         res->graph      = graph_self;
 142         res->nodes      = new_set(cmp_node, 64);
 143         res->edges      = new_set(cmp_edge, 128);
 144
 145         res->pre_num  = 0;
 146         res->post_num = 0;
 147         res->edges_classified = 0;
 148
 149         obstack_init(&res->obst);
 150
 151         dfs_perform(res, graph_impl->get_root(graph_self), NULL);
 152         classify_edges(res);
 153
 154         res->pre_order = xmalloc(res->pre_num * sizeof(res->pre_order));
 155         res->post_order = xmalloc(res->pre_num * sizeof(res->post_order));
 156         foreach_set (res->nodes, node) {
 157                 res->pre_order[node->pre_num] = node;
 158                 res->post_order[node->post_num] = node;
 159         }
 160
 161         return res;
 162 }
 163
 164 void dfs_free(dfs_t *dfs)
 165 {
 166         del_set(dfs->nodes);
 167         del_set(dfs->edges);
 168         xfree(dfs->pre_order);
 169         xfree(dfs->post_order);
 170         xfree(dfs);
 171 }
 172
 173 void dfs_dump(const dfs_t *dfs, FILE *file)
 174 {
 175         dfs_node_t *node;
 176         dfs_edge_t *edge;
 177
 178         ir_fprintf(file, "digraph G {\n");
 179         foreach_set (dfs->nodes, node) {
 180                 ir_fprintf(file, "\tn%d [shape=box,label=\"%+F\\l%d/%d %d\"];\n",
 181                                 node->pre_num, node->node, node->pre_num, node->post_num, node->max_pre_num);
 182
 183         }
 184
 185         foreach_set (dfs->edges, edge) {
 186                 dfs_node_t *src = edge->s;
 187                 dfs_node_t *tgt = edge->t;
 188                 const char *s, *color;
 189
 190 #define XXX(e)          case DFS_EDGE_ ## e: s = #e; break
 191                 switch (edge->kind) {
 192                         XXX(BACK);
 193                         XXX(FWD);
 194                         XXX(CROSS);
 195                         XXX(ANC);
 196                         default:
 197                         s = "?";
 198                 }
 199 #undef XXX
 200
 201 #define XXX(e)  case DFS_EDGE_ ## e
 202                 switch (edge->kind) {
 203                         XXX(ANC):   color = "black"; break;
 204                         XXX(FWD):   color = "blue"; break;
 205                         XXX(CROSS): color = "red"; break;
 206                         XXX(BACK):  color = "darkviolet"; break;
 207                         default: color = "?";
 208                 }
 209 #undef XXX
 210
 211                 ir_fprintf(file, "\tn%d -> n%d [label=\"%s\",color=\"%s\"];\n", src->pre_num, tgt->pre_num, s, color);
 212         }
 213
 214         ir_fprintf(file, "}\n");
 215 }