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  * @brief
  25  *
  26  * Simple depth first search on CFGs.
  27  */
  28 #include <config.h>
  29
  30 #include <stdlib.h>
  31
  32 #define DISABLE_STATEV
  33
  34 #include <assert.h>
  35 #include "irprintf.h"
  36 #include "irdom_t.h"
  37 #include "set.h"
  38 #include "statev.h"
  39 #include "dfs_t.h"
  40 #include "util.h"
  41
  42 static int cmp_edge(const void *a, const void *b, size_t sz)
  43 {
  44         const dfs_edge_t *p = (const dfs_edge_t*) a;
  45         const dfs_edge_t *q = (const dfs_edge_t*) 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 = (const dfs_node_t*) a;
  54         const dfs_node_t *q = (const dfs_node_t*) 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 = (dfs_edge_kind_t) -1;
  70
  71         return (dfs_edge_t*) 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 = (void**) 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         stat_ev_cnt_decl(anc);
 118         stat_ev_cnt_decl(back);
 119         stat_ev_cnt_decl(fwd);
 120         stat_ev_cnt_decl(cross);
 121
 122         foreach_set (dfs->edges, dfs_edge_t*, edge) {
 123                 dfs_node_t *src = edge->s;
 124                 dfs_node_t *tgt = edge->t;
 125
 126                 if (tgt->ancestor == src) {
 127                         stat_ev_cnt_inc(anc);
 128                         edge->kind = DFS_EDGE_ANC;
 129                 }
 130                 else if (_dfs_int_is_ancestor(tgt, src)) {
 131                         stat_ev_cnt_inc(back);
 132                         edge->kind = DFS_EDGE_BACK;
 133                 }
 134                 else if (_dfs_int_is_ancestor(src, tgt)) {
 135                         stat_ev_cnt_inc(fwd);
 136                         edge->kind = DFS_EDGE_FWD;
 137                 }
 138                 else {
 139                         stat_ev_cnt_inc(cross);
 140                         edge->kind = DFS_EDGE_CROSS;
 141                 }
 142         }
 143
 144         stat_ev_cnt_done(anc,   "dfs_edge_anc");
 145         stat_ev_cnt_done(back,  "dfs_edge_back");
 146         stat_ev_cnt_done(fwd,   "dfs_edge_fwd");
 147         stat_ev_cnt_done(cross, "dfs_edge_cross");
 148 }
 149
 150 dfs_edge_kind_t dfs_get_edge_kind(const dfs_t *dfs, const void *a, const void *b)
 151 {
 152         if (!dfs->edges_classified) {
 153                 dfs_t *urg = (dfs_t *) dfs;
 154                 classify_edges(urg);
 155                 urg->edges_classified = 1;
 156         }
 157         return get_edge(dfs, a, b)->kind;
 158 }
 159
 160 dfs_t *dfs_new(const absgraph_t *graph_impl, void *graph_self)
 161 {
 162         dfs_t *res = XMALLOC(dfs_t);
 163         dfs_node_t *node;
 164
 165         res->graph_impl = graph_impl;
 166         res->graph      = graph_self;
 167         res->nodes      = new_set(cmp_node, 64);
 168         res->edges      = new_set(cmp_edge, 128);
 169
 170         res->pre_num  = 0;
 171         res->post_num = 0;
 172         res->edges_classified = 0;
 173
 174         obstack_init(&res->obst);
 175
 176         dfs_perform(res, graph_impl->get_root(graph_self), NULL, 0);
 177
 178         /* make sure the end node (which might not be accessible) has a number */
 179         node = get_node(res, graph_impl->get_end(graph_self));
 180         if (!node->visited) {
 181                 node->visited     = 1;
 182                 node->node        = graph_impl->get_end(graph_self);
 183                 node->ancestor    = NULL;
 184                 node->pre_num     = res->pre_num++;
 185                 node->post_num    = res->post_num++;
 186                 node->max_pre_num = node->pre_num;
 187                 node->level       = 0;
 188         }
 189
 190         classify_edges(res);
 191
 192         assert(res->pre_num == res->post_num);
 193         res->pre_order  = XMALLOCN(dfs_node_t*, res->pre_num);
 194         res->post_order = XMALLOCN(dfs_node_t*, res->post_num);
 195         foreach_set (res->nodes, dfs_node_t*, node) {
 196                 assert(node->pre_num < res->pre_num);
 197                 assert(node->post_num < res->post_num);
 198
 199                 res->pre_order[node->pre_num] = node;
 200                 res->post_order[node->post_num] = node;
 201         }
 202
 203         stat_ev_dbl("dfs_n_blocks", res->pre_num);
 204
 205         return res;
 206 }
 207
 208 void dfs_free(dfs_t *dfs)
 209 {
 210         del_set(dfs->nodes);
 211         del_set(dfs->edges);
 212         xfree(dfs->pre_order);
 213         xfree(dfs->post_order);
 214         xfree(dfs);
 215 }
 216
 217 static void dfs_dump_edge(const dfs_edge_t *edge, FILE *file)
 218 {
 219         dfs_node_t *src = edge->s;
 220         dfs_node_t *tgt = edge->t;
 221         const char *s, *style;
 222         int weight;
 223
 224 #define XXX(e)   case DFS_EDGE_ ## e: s = #e; break
 225         switch (edge->kind) {
 226                 XXX(FWD);
 227                 XXX(CROSS);
 228                 default:
 229                 s = "";
 230         }
 231 #undef XXX
 232
 233         weight = edge->kind == DFS_EDGE_BACK ? 1 : 1000;
 234         style  = edge->kind == DFS_EDGE_BACK ? "dashed" : "solid";
 235
 236         ir_fprintf(file, "\tn%d -> n%d [label=\"%s\",style=\"%s\",weight=\"%d\"];\n", src->pre_num, tgt->pre_num, s, style, weight);
 237 }
 238
 239 static int node_level_cmp(const void *a, const void *b)
 240 {
 241         const dfs_node_t *p = *(const dfs_node_t **) a;
 242         const dfs_node_t *q = *(const dfs_node_t **) b;
 243
 244         if (p->level == q->level)
 245                 return p->pre_num - q->pre_num;
 246         return p->level - q->level;
 247 }
 248
 249 void dfs_dump(const dfs_t *dfs, FILE *file)
 250 {
 251         dfs_node_t **nodes = XMALLOCN(dfs_node_t*, dfs->pre_num);
 252         dfs_node_t *node;
 253         dfs_edge_t *edge;
 254         int i, n = 0;
 255
 256         ir_fprintf(file, "digraph G {\nranksep=0.5\n");
 257         foreach_set (dfs->nodes, dfs_node_t*, node) {
 258                 nodes[n++] = node;
 259         }
 260
 261         qsort(nodes, n, sizeof(nodes[0]), node_level_cmp);
 262
 263         i = 0;
 264         while (i < n) {
 265                 int level = nodes[i]->level;
 266
 267                 ir_fprintf(file, "\t{ rank = same; ");
 268                 for (; i < n && nodes[i]->level == level; ++i)
 269                         ir_fprintf(file, "n%d;", nodes[i]->pre_num);
 270                 ir_fprintf(file, "}\n");
 271
 272
 273         }
 274
 275         for (i = 0; i < n; ++i) {
 276                 node = nodes[i];
 277                 ir_fprintf(file, "\tn%d [label=\"%d\"]\n", node->pre_num, get_Block_dom_tree_pre_num((ir_node*) node->node));
 278 #if 0
 279                 ir_fprintf(file, "\tn%d [shape=box,label=\"%+F\\l%d %d/%d %d\"];\n",
 280                                 node->pre_num, node->node, get_Block_dom_tree_pre_num(node->node),
 281                                 node->pre_num, node->post_num, node->max_pre_num);
 282 #endif
 283         }
 284
 285         foreach_set (dfs->edges, dfs_edge_t*, edge)
 286                 dfs_dump_edge(edge, file);
 287
 288         ir_fprintf(file, "}\n");
 289         xfree(nodes);
 290 }