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 #ifdef HAVE_CONFIG_H
  30 #include <config.h>
  31 #endif
  32
  33 #include <stdlib.h>
  34
  35 #include <assert.h>
  36 #include "irtools.h"
  37 #include "irprintf.h"
  38 #include "irdom.h"
  39 #include "set.h"
  40 #include "dfs_t.h"
  41
  42 static int cmp_edge(const void *a, const void *b, size_t sz)
  43 {
  44         const dfs_edge_t *p = a;
  45         const dfs_edge_t *q = b;
  46         (void) sz;
  47
  48         return !(p->src == q->src && p->tgt == q->tgt);
  49 }
  50
  51 static int cmp_node(const void *a, const void *b, size_t sz)
  52 {
  53         const dfs_node_t *p = a;
  54         const dfs_node_t *q = b;
  55         (void) sz;
  56
  57         return p->node != q->node;
  58 }
  59
  60 #define get_node(dfs, node) _dfs_get_node(dfs, node)
  61
  62 static dfs_edge_t *get_edge(const dfs_t *self, const void *src, const void *tgt)
  63 {
  64         unsigned hash = HASH_COMBINE(HASH_PTR(src), HASH_PTR(tgt));
  65         dfs_edge_t templ;
  66
  67         templ.src = src;
  68         templ.tgt = tgt;
  69         templ.kind = -1;
  70
  71         return set_insert(self->edges, &templ, sizeof(templ), hash);
  72 }
  73
  74 static void dfs_perform(dfs_t *dfs, void *n, void *anc, int level)
  75 {
  76         dfs_node_t *node = get_node(dfs, n);
  77         void **succs, **iter;
  78
  79         assert(node->visited == 0);
  80
  81         node->visited     = 1;
  82         node->node        = n;
  83         node->ancestor    = anc;
  84         node->pre_num     = dfs->pre_num++;
  85         node->max_pre_num = node->pre_num;
  86         node->level       = level;
  87
  88         dfs->graph_impl->grow_succs(dfs->graph, n, &dfs->obst);
  89         obstack_ptr_grow(&dfs->obst, NULL);
  90         succs = obstack_finish(&dfs->obst);
  91
  92         for (iter = succs; *iter; ++iter) {
  93                 void *p = *iter;
  94
  95                 /* get the node */
  96                 dfs_node_t *child = get_node(dfs, p);
  97
  98                 /* create the edge object */
  99                 dfs_edge_t *edge = get_edge(dfs, n, p);
 100                 edge->s = node;
 101                 edge->t = child;
 102
 103                 if (!child->visited)
 104                         dfs_perform(dfs, p, node, level + 1);
 105
 106                 /* get the maximum pre num of the subtree. needed for ancestor determination. */
 107                 node->max_pre_num = MAX(node->max_pre_num, child->max_pre_num);
 108         }
 109
 110         node->post_num = dfs->post_num++;
 111         obstack_free(&dfs->obst, succs);
 112 }
 113
 114 static void classify_edges(dfs_t *dfs)
 115 {
 116         dfs_edge_t *edge;
 117
 118         foreach_set (dfs->edges, edge) {
 119                 dfs_node_t *src = edge->s;
 120                 dfs_node_t *tgt = edge->t;
 121
 122                 if (tgt->ancestor == src)
 123                         edge->kind = DFS_EDGE_ANC;
 124                 else if (_dfs_int_is_ancestor(tgt, src))
 125                         edge->kind = DFS_EDGE_BACK;
 126                 else if (_dfs_int_is_ancestor(src, tgt))
 127                         edge->kind = DFS_EDGE_FWD;
 128                 else
 129                         edge->kind = DFS_EDGE_CROSS;
 130         }
 131 }
 132
 133 dfs_edge_kind_t dfs_get_edge_kind(const dfs_t *dfs, const void *a, const void *b)
 134 {
 135         if (!dfs->edges_classified) {
 136                 dfs_t *urg = (dfs_t *) dfs;
 137                 classify_edges(urg);
 138                 urg->edges_classified = 1;
 139         }
 140         return get_edge(dfs, a, b)->kind;
 141 }
 142
 143 dfs_t *dfs_new(const absgraph_t *graph_impl, void *graph_self)
 144 {
 145         dfs_t *res = xmalloc(sizeof(res[0]));
 146         dfs_node_t *node;
 147
 148         res->graph_impl = graph_impl;
 149         res->graph      = graph_self;
 150         res->nodes      = new_set(cmp_node, 64);
 151         res->edges      = new_set(cmp_edge, 128);
 152
 153         res->pre_num  = 0;
 154         res->post_num = 0;
 155         res->edges_classified = 0;
 156
 157         obstack_init(&res->obst);
 158
 159         dfs_perform(res, graph_impl->get_root(graph_self), NULL, 0);
 160         classify_edges(res);
 161
 162         res->pre_order = xmalloc(res->pre_num * sizeof(res->pre_order));
 163         res->post_order = xmalloc(res->pre_num * sizeof(res->post_order));
 164         foreach_set (res->nodes, node) {
 165                 res->pre_order[node->pre_num] = node;
 166                 res->post_order[node->post_num] = node;
 167         }
 168
 169         return res;
 170 }
 171
 172 void dfs_free(dfs_t *dfs)
 173 {
 174         del_set(dfs->nodes);
 175         del_set(dfs->edges);
 176         xfree(dfs->pre_order);
 177         xfree(dfs->post_order);
 178         xfree(dfs);
 179 }
 180
 181 static void dfs_dump_edge(const dfs_edge_t *edge, FILE *file)
 182 {
 183         dfs_node_t *src = edge->s;
 184         dfs_node_t *tgt = edge->t;
 185         const char *s, *style;
 186         int weight;
 187
 188 #define XXX(e)          case DFS_EDGE_ ## e: s = #e; break
 189         switch (edge->kind) {
 190                 XXX(FWD);
 191                 XXX(CROSS);
 192                 default:
 193                 s = "";
 194         }
 195 #undef XXX
 196
 197         weight = edge->kind == DFS_EDGE_BACK ? 1 : 1000;
 198         style  = edge->kind == DFS_EDGE_BACK ? "dashed" : "solid";
 199
 200         ir_fprintf(file, "\tn%d -> n%d [label=\"%s\",style=\"%s\",weight=\"%d\"];\n", src->pre_num, tgt->pre_num, s, style, weight);
 201 }
 202
 203 static int node_level_cmp(const void *a, const void *b)
 204 {
 205         const dfs_node_t *p = *(const dfs_node_t **) a;
 206         const dfs_node_t *q = *(const dfs_node_t **) b;
 207
 208         if (p->level == q->level)
 209                 return p->pre_num - q->pre_num;
 210         return p->level - q->level;
 211 }
 212
 213 void dfs_dump(const dfs_t *dfs, FILE *file)
 214 {
 215         dfs_node_t **nodes = xmalloc(dfs->pre_num * sizeof(nodes[0]));
 216         dfs_node_t *node;
 217         dfs_edge_t *edge;
 218         int i, n = 0;
 219
 220         ir_fprintf(file, "digraph G {\nranksep=0.5\n");
 221         foreach_set (dfs->nodes, node) {
 222                 nodes[n++] = node;
 223         }
 224
 225         qsort(nodes, n, sizeof(nodes[0]), node_level_cmp);
 226
 227         i = 0;
 228         while (i < n) {
 229                 int level = nodes[i]->level;
 230
 231                 ir_fprintf(file, "\t{ rank = same; ");
 232                 for (; i < n && nodes[i]->level == level; ++i)
 233                         ir_fprintf(file, "n%d;", nodes[i]->pre_num);
 234                 ir_fprintf(file, "}\n");
 235
 236
 237         }
 238
 239         for (i = 0; i < n; ++i) {
 240                 dfs_node_t *node = nodes[i];
 241                 ir_fprintf(file, "\tn%d [label=\"%d\"]\n", node->pre_num, get_Block_dom_tree_pre_num(node->node));
 242 #if 0
 243                 ir_fprintf(file, "\tn%d [shape=box,label=\"%+F\\l%d %d/%d %d\"];\n",
 244                                 node->pre_num, node->node, get_Block_dom_tree_pre_num(node->node),
 245                                 node->pre_num, node->post_num, node->max_pre_num);
 246 #endif
 247         }
 248
 249         foreach_set (dfs->edges, edge)
 250                 dfs_dump_edge(edge, file);
 251
 252         ir_fprintf(file, "}\n");
 253         xfree(nodes);
 254 }