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

   1 /*
   2  * Copyright (C) 1995-2008 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 #define DISABLE_STATEV
  36
  37 #include <assert.h>
  38 #include "irtools.h"
  39 #include "irprintf.h"
  40 #include "irdom.h"
  41 #include "set.h"
  42 #include "statev.h"
  43 #include "dfs_t.h"
  44
  45 static int cmp_edge(const void *a, const void *b, size_t sz)
  46 {
  47         const dfs_edge_t *p = a;
  48         const dfs_edge_t *q = b;
  49         (void) sz;
  50
  51         return !(p->src == q->src && p->tgt == q->tgt);
  52 }
  53
  54 static int cmp_node(const void *a, const void *b, size_t sz)
  55 {
  56         const dfs_node_t *p = a;
  57         const dfs_node_t *q = b;
  58         (void) sz;
  59
  60         return p->node != q->node;
  61 }
  62
  63 #define get_node(dfs, node) _dfs_get_node(dfs, node)
  64
  65 static dfs_edge_t *get_edge(const dfs_t *self, const void *src, const void *tgt)
  66 {
  67         unsigned hash = HASH_COMBINE(HASH_PTR(src), HASH_PTR(tgt));
  68         dfs_edge_t templ;
  69
  70         templ.src = src;
  71         templ.tgt = tgt;
  72         templ.kind = -1;
  73
  74         return set_insert(self->edges, &templ, sizeof(templ), hash);
  75 }
  76
  77 static void dfs_perform(dfs_t *dfs, void *n, void *anc, int level)
  78 {
  79         dfs_node_t *node = get_node(dfs, n);
  80         void **succs, **iter;
  81
  82         assert(node->visited == 0);
  83
  84         node->visited     = 1;
  85         node->node        = n;
  86         node->ancestor    = anc;
  87         node->pre_num     = dfs->pre_num++;
  88         node->max_pre_num = node->pre_num;
  89         node->level       = level;
  90
  91         dfs->graph_impl->grow_succs(dfs->graph, n, &dfs->obst);
  92         obstack_ptr_grow(&dfs->obst, NULL);
  93         succs = obstack_finish(&dfs->obst);
  94
  95         for (iter = succs; *iter; ++iter) {
  96                 void *p = *iter;
  97
  98                 /* get the node */
  99                 dfs_node_t *child = get_node(dfs, p);
 100
 101                 /* create the edge object */
 102                 dfs_edge_t *edge = get_edge(dfs, n, p);
 103                 edge->s = node;
 104                 edge->t = child;
 105
 106                 if (!child->visited)
 107                         dfs_perform(dfs, p, node, level + 1);
 108
 109                 /* get the maximum pre num of the subtree. needed for ancestor determination. */
 110                 node->max_pre_num = MAX(node->max_pre_num, child->max_pre_num);
 111         }
 112
 113         node->post_num = dfs->post_num++;
 114         obstack_free(&dfs->obst, succs);
 115 }
 116
 117 static void classify_edges(dfs_t *dfs)
 118 {
 119         dfs_edge_t *edge;
 120         stat_ev_cnt_decl(anc);
 121         stat_ev_cnt_decl(back);
 122         stat_ev_cnt_decl(fwd);
 123         stat_ev_cnt_decl(cross);
 124
 125         foreach_set (dfs->edges, edge) {
 126                 dfs_node_t *src = edge->s;
 127                 dfs_node_t *tgt = edge->t;
 128
 129                 if (tgt->ancestor == src) {
 130                         stat_ev_cnt_inc(anc);
 131                         edge->kind = DFS_EDGE_ANC;
 132                 }
 133                 else if (_dfs_int_is_ancestor(tgt, src)) {
 134                         stat_ev_cnt_inc(back);
 135                         edge->kind = DFS_EDGE_BACK;
 136                 }
 137                 else if (_dfs_int_is_ancestor(src, tgt)) {
 138                         stat_ev_cnt_inc(fwd);
 139                         edge->kind = DFS_EDGE_FWD;
 140                 }
 141                 else {
 142                         stat_ev_cnt_inc(cross);
 143                         edge->kind = DFS_EDGE_CROSS;
 144                 }
 145         }
 146
 147         stat_ev_cnt_done(anc,   "dfs_edge_anc");
 148         stat_ev_cnt_done(back,  "dfs_edge_back");
 149         stat_ev_cnt_done(fwd,   "dfs_edge_fwd");
 150         stat_ev_cnt_done(cross, "dfs_edge_cross");
 151 }
 152
 153 dfs_edge_kind_t dfs_get_edge_kind(const dfs_t *dfs, const void *a, const void *b)
 154 {
 155         if (!dfs->edges_classified) {
 156                 dfs_t *urg = (dfs_t *) dfs;
 157                 classify_edges(urg);
 158                 urg->edges_classified = 1;
 159         }
 160         return get_edge(dfs, a, b)->kind;
 161 }
 162
 163 dfs_t *dfs_new(const absgraph_t *graph_impl, void *graph_self)
 164 {
 165         dfs_t *res = XMALLOC(dfs_t);
 166         dfs_node_t *node;
 167
 168         res->graph_impl = graph_impl;
 169         res->graph      = graph_self;
 170         res->nodes      = new_set(cmp_node, 64);
 171         res->edges      = new_set(cmp_edge, 128);
 172
 173         res->pre_num  = 0;
 174         res->post_num = 0;
 175         res->edges_classified = 0;
 176
 177         obstack_init(&res->obst);
 178
 179         dfs_perform(res, graph_impl->get_root(graph_self), NULL, 0);
 180
 181         /* make sure the end node (which might not be accessible) has a number */
 182         node = get_node(res, graph_impl->get_end(graph_self));
 183         if (!node->visited) {
 184                 node->visited     = 1;
 185                 node->node        = graph_impl->get_end(graph_self);
 186                 node->ancestor    = NULL;
 187                 node->pre_num     = res->pre_num++;
 188                 node->post_num    = res->post_num++;
 189                 node->max_pre_num = node->pre_num;
 190                 node->level       = 0;
 191         }
 192
 193         classify_edges(res);
 194
 195         assert(res->pre_num == res->post_num);
 196         res->pre_order  = XMALLOCN(dfs_node_t*, res->pre_num);
 197         res->post_order = XMALLOCN(dfs_node_t*, res->post_num);
 198         foreach_set (res->nodes, node) {
 199                 assert(node->pre_num < res->pre_num);
 200                 assert(node->post_num < res->post_num);
 201
 202                 res->pre_order[node->pre_num] = node;
 203                 res->post_order[node->post_num] = node;
 204         }
 205
 206         stat_ev_dbl("dfs_n_blocks", res->pre_num);
 207
 208         return res;
 209 }
 210
 211 void dfs_free(dfs_t *dfs)
 212 {
 213         del_set(dfs->nodes);
 214         del_set(dfs->edges);
 215         xfree(dfs->pre_order);
 216         xfree(dfs->post_order);
 217         xfree(dfs);
 218 }
 219
 220 static void dfs_dump_edge(const dfs_edge_t *edge, FILE *file)
 221 {
 222         dfs_node_t *src = edge->s;
 223         dfs_node_t *tgt = edge->t;
 224         const char *s, *style;
 225         int weight;
 226
 227 #define XXX(e)          case DFS_EDGE_ ## e: s = #e; break
 228         switch (edge->kind) {
 229                 XXX(FWD);
 230                 XXX(CROSS);
 231                 default:
 232                 s = "";
 233         }
 234 #undef XXX
 235
 236         weight = edge->kind == DFS_EDGE_BACK ? 1 : 1000;
 237         style  = edge->kind == DFS_EDGE_BACK ? "dashed" : "solid";
 238
 239         ir_fprintf(file, "\tn%d -> n%d [label=\"%s\",style=\"%s\",weight=\"%d\"];\n", src->pre_num, tgt->pre_num, s, style, weight);
 240 }
 241
 242 static int node_level_cmp(const void *a, const void *b)
 243 {
 244         const dfs_node_t *p = *(const dfs_node_t **) a;
 245         const dfs_node_t *q = *(const dfs_node_t **) b;
 246
 247         if (p->level == q->level)
 248                 return p->pre_num - q->pre_num;
 249         return p->level - q->level;
 250 }
 251
 252 void dfs_dump(const dfs_t *dfs, FILE *file)
 253 {
 254         dfs_node_t **nodes = XMALLOCN(dfs_node_t*, dfs->pre_num);
 255         dfs_node_t *node;
 256         dfs_edge_t *edge;
 257         int i, n = 0;
 258
 259         ir_fprintf(file, "digraph G {\nranksep=0.5\n");
 260         foreach_set (dfs->nodes, node) {
 261                 nodes[n++] = node;
 262         }
 263
 264         qsort(nodes, n, sizeof(nodes[0]), node_level_cmp);
 265
 266         i = 0;
 267         while (i < n) {
 268                 int level = nodes[i]->level;
 269
 270                 ir_fprintf(file, "\t{ rank = same; ");
 271                 for (; i < n && nodes[i]->level == level; ++i)
 272                         ir_fprintf(file, "n%d;", nodes[i]->pre_num);
 273                 ir_fprintf(file, "}\n");
 274
 275
 276         }
 277
 278         for (i = 0; i < n; ++i) {
 279                 dfs_node_t *node = nodes[i];
 280                 ir_fprintf(file, "\tn%d [label=\"%d\"]\n", node->pre_num, get_Block_dom_tree_pre_num(node->node));
 281 #if 0
 282                 ir_fprintf(file, "\tn%d [shape=box,label=\"%+F\\l%d %d/%d %d\"];\n",
 283                                 node->pre_num, node->node, get_Block_dom_tree_pre_num(node->node),
 284                                 node->pre_num, node->post_num, node->max_pre_num);
 285 #endif
 286         }
 287
 288         foreach_set (dfs->edges, edge)
 289                 dfs_dump_edge(edge, file);
 290
 291         ir_fprintf(file, "}\n");
 292         xfree(nodes);
 293 }