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 "statev.h"
  41 #include "dfs_t.h"
  42
  43 static int cmp_edge(const void *a, const void *b, size_t sz)
  44 {
  45         const dfs_edge_t *p = a;
  46         const dfs_edge_t *q = b;
  47         (void) sz;
  48
  49         return !(p->src == q->src && p->tgt == q->tgt);
  50 }
  51
  52 static int cmp_node(const void *a, const void *b, size_t sz)
  53 {
  54         const dfs_node_t *p = a;
  55         const dfs_node_t *q = b;
  56         (void) sz;
  57
  58         return p->node != q->node;
  59 }
  60
  61 #define get_node(dfs, node) _dfs_get_node(dfs, node)
  62
  63 static dfs_edge_t *get_edge(const dfs_t *self, const void *src, const void *tgt)
  64 {
  65         unsigned hash = HASH_COMBINE(HASH_PTR(src), HASH_PTR(tgt));
  66         dfs_edge_t templ;
  67
  68         templ.src = src;
  69         templ.tgt = tgt;
  70         templ.kind = -1;
  71
  72         return set_insert(self->edges, &templ, sizeof(templ), hash);
  73 }
  74
  75 static void dfs_perform(dfs_t *dfs, void *n, void *anc, int level)
  76 {
  77         dfs_node_t *node = get_node(dfs, n);
  78         void **succs, **iter;
  79
  80         assert(node->visited == 0);
  81
  82         node->visited     = 1;
  83         node->node        = n;
  84         node->ancestor    = anc;
  85         node->pre_num     = dfs->pre_num++;
  86         node->max_pre_num = node->pre_num;
  87         node->level       = level;
  88
  89         dfs->graph_impl->grow_succs(dfs->graph, n, &dfs->obst);
  90         obstack_ptr_grow(&dfs->obst, NULL);
  91         succs = obstack_finish(&dfs->obst);
  92
  93         for (iter = succs; *iter; ++iter) {
  94                 void *p = *iter;
  95
  96                 /* get the node */
  97                 dfs_node_t *child = get_node(dfs, p);
  98
  99                 /* create the edge object */
 100                 dfs_edge_t *edge = get_edge(dfs, n, p);
 101                 edge->s = node;
 102                 edge->t = child;
 103
 104                 if (!child->visited)
 105                         dfs_perform(dfs, p, node, level + 1);
 106
 107                 /* get the maximum pre num of the subtree. needed for ancestor determination. */
 108                 node->max_pre_num = MAX(node->max_pre_num, child->max_pre_num);
 109         }
 110
 111         node->post_num = dfs->post_num++;
 112         obstack_free(&dfs->obst, succs);
 113 }
 114
 115 static void classify_edges(dfs_t *dfs)
 116 {
 117         stat_ev_cnt_decl(anc);
 118         stat_ev_cnt_decl(back);
 119         stat_ev_cnt_decl(fwd);
 120         stat_ev_cnt_decl(cross);
 121         dfs_edge_t *edge;
 122
 123         foreach_set (dfs->edges, edge) {
 124                 dfs_node_t *src = edge->s;
 125                 dfs_node_t *tgt = edge->t;
 126
 127                 if (tgt->ancestor == src) {
 128                         stat_ev_cnt_inc(anc);
 129                         edge->kind = DFS_EDGE_ANC;
 130                 }
 131                 else if (_dfs_int_is_ancestor(tgt, src)) {
 132                         stat_ev_cnt_inc(back);
 133                         edge->kind = DFS_EDGE_BACK;
 134                 }
 135                 else if (_dfs_int_is_ancestor(src, tgt)) {
 136                         stat_ev_cnt_inc(fwd);
 137                         edge->kind = DFS_EDGE_FWD;
 138                 }
 139                 else {
 140                         stat_ev_cnt_inc(cross);
 141                         edge->kind = DFS_EDGE_CROSS;
 142                 }
 143         }
 144
 145         stat_ev_cnt_done(anc,   "dfs_edge_anc");
 146         stat_ev_cnt_done(back,  "dfs_edge_back");
 147         stat_ev_cnt_done(fwd,   "dfs_edge_fwd");
 148         stat_ev_cnt_done(cross, "dfs_edge_cross");
 149 }
 150
 151 dfs_edge_kind_t dfs_get_edge_kind(const dfs_t *dfs, const void *a, const void *b)
 152 {
 153         if (!dfs->edges_classified) {
 154                 dfs_t *urg = (dfs_t *) dfs;
 155                 classify_edges(urg);
 156                 urg->edges_classified = 1;
 157         }
 158         return get_edge(dfs, a, b)->kind;
 159 }
 160
 161 dfs_t *dfs_new(const absgraph_t *graph_impl, void *graph_self)
 162 {
 163         dfs_t *res = xmalloc(sizeof(res[0]));
 164         dfs_node_t *node;
 165
 166         res->graph_impl = graph_impl;
 167         res->graph      = graph_self;
 168         res->nodes      = new_set(cmp_node, 64);
 169         res->edges      = new_set(cmp_edge, 128);
 170
 171         res->pre_num  = 0;
 172         res->post_num = 0;
 173         res->edges_classified = 0;
 174
 175         obstack_init(&res->obst);
 176
 177         dfs_perform(res, graph_impl->get_root(graph_self), NULL, 0);
 178
 179         /* make sure the end node (which might not be accessible) has a number */
 180         node = get_node(res, graph_impl->get_end(graph_self));
 181         if (!node->visited) {
 182                 node->visited     = 1;
 183                 node->node        = graph_impl->get_end(graph_self);
 184                 node->ancestor    = NULL;
 185                 node->pre_num     = res->pre_num++;
 186                 node->post_num    = res->post_num++;
 187                 node->max_pre_num = node->pre_num;
 188                 node->level       = 0;
 189         }
 190
 191         classify_edges(res);
 192
 193         assert(res->pre_num == res->post_num);
 194         res->pre_order = xmalloc(res->pre_num * sizeof(res->pre_order));
 195         res->post_order = xmalloc(res->post_num * sizeof(res->post_order));
 196         foreach_set (res->nodes, node) {
 197                 assert(node->pre_num < res->pre_num);
 198                 assert(node->post_num < res->post_num);
 199
 200                 res->pre_order[node->pre_num] = node;
 201                 res->post_order[node->post_num] = node;
 202         }
 203
 204         stat_ev_dbl("dfs_n_blocks", res->pre_num);
 205
 206         return res;
 207 }
 208
 209 void dfs_free(dfs_t *dfs)
 210 {
 211         del_set(dfs->nodes);
 212         del_set(dfs->edges);
 213         xfree(dfs->pre_order);
 214         xfree(dfs->post_order);
 215         xfree(dfs);
 216 }
 217
 218 static void dfs_dump_edge(const dfs_edge_t *edge, FILE *file)
 219 {
 220         dfs_node_t *src = edge->s;
 221         dfs_node_t *tgt = edge->t;
 222         const char *s, *style;
 223         int weight;
 224
 225 #define XXX(e)          case DFS_EDGE_ ## e: s = #e; break
 226         switch (edge->kind) {
 227                 XXX(FWD);
 228                 XXX(CROSS);
 229                 default:
 230                 s = "";
 231         }
 232 #undef XXX
 233
 234         weight = edge->kind == DFS_EDGE_BACK ? 1 : 1000;
 235         style  = edge->kind == DFS_EDGE_BACK ? "dashed" : "solid";
 236
 237         ir_fprintf(file, "\tn%d -> n%d [label=\"%s\",style=\"%s\",weight=\"%d\"];\n", src->pre_num, tgt->pre_num, s, style, weight);
 238 }
 239
 240 static int node_level_cmp(const void *a, const void *b)
 241 {
 242         const dfs_node_t *p = *(const dfs_node_t **) a;
 243         const dfs_node_t *q = *(const dfs_node_t **) b;
 244
 245         if (p->level == q->level)
 246                 return p->pre_num - q->pre_num;
 247         return p->level - q->level;
 248 }
 249
 250 void dfs_dump(const dfs_t *dfs, FILE *file)
 251 {
 252         dfs_node_t **nodes = xmalloc(dfs->pre_num * sizeof(nodes[0]));
 253         dfs_node_t *node;
 254         dfs_edge_t *edge;
 255         int i, n = 0;
 256
 257         ir_fprintf(file, "digraph G {\nranksep=0.5\n");
 258         foreach_set (dfs->nodes, node) {
 259                 nodes[n++] = node;
 260         }
 261
 262         qsort(nodes, n, sizeof(nodes[0]), node_level_cmp);
 263
 264         i = 0;
 265         while (i < n) {
 266                 int level = nodes[i]->level;
 267
 268                 ir_fprintf(file, "\t{ rank = same; ");
 269                 for (; i < n && nodes[i]->level == level; ++i)
 270                         ir_fprintf(file, "n%d;", nodes[i]->pre_num);
 271                 ir_fprintf(file, "}\n");
 272
 273
 274         }
 275
 276         for (i = 0; i < n; ++i) {
 277                 dfs_node_t *node = nodes[i];
 278                 ir_fprintf(file, "\tn%d [label=\"%d\"]\n", node->pre_num, get_Block_dom_tree_pre_num(node->node));
 279 #if 0
 280                 ir_fprintf(file, "\tn%d [shape=box,label=\"%+F\\l%d %d/%d %d\"];\n",
 281                                 node->pre_num, node->node, get_Block_dom_tree_pre_num(node->node),
 282                                 node->pre_num, node->post_num, node->max_pre_num);
 283 #endif
 284         }
 285
 286         foreach_set (dfs->edges, edge)
 287                 dfs_dump_edge(edge, file);
 288
 289         ir_fprintf(file, "}\n");
 290         xfree(nodes);
 291 }