nsz Git - libfirm/blob - ir/ir/irgwalk.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
  22  * @brief   Functions for traversing ir graphs
  23  * @author  Boris Boesler, Goetz Lindenmaier, Michael Beck
  24  * @version $Id$
  25  * @summary
  26  *  traverse an ir graph
  27  *  - execute the pre function before recursion
  28  *  - execute the post function after recursion
  29  */
  30 #ifdef HAVE_CONFIG_H
  31 # include "config.h"
  32 #endif
  33
  34 #ifdef HAVE_STDLIB_H
  35 # include <stdlib.h>
  36 #endif
  37
  38 #include "irnode_t.h"
  39 #include "irgraph_t.h"
  40 #include "irprog.h"
  41 #include "irgwalk.h"
  42 #include "irhooks.h"
  43 #include "ircgcons.h"
  44 #include "entity_t.h"
  45
  46 #include "error.h"
  47 #include "pset_new.h"
  48 #include "array.h"
  49
  50 /**
  51  * Walk over an interprocedural graph (callgraph).
  52  * Visits only graphs in irg_set.
  53  */
  54 static void irg_walk_cg(ir_node * node, ir_visited_t visited,
  55                         pset_new_t *irg_set, irg_walk_func *pre,
  56                         irg_walk_func *post, void * env) {
  57         int i;
  58         ir_graph * rem = current_ir_graph;
  59         ir_node * pred;
  60
  61         assert(node && node->kind == k_ir_node);
  62         if (get_irn_visited(node) >= visited) return;
  63
  64         set_irn_visited(node, visited);
  65
  66         if (pre) pre(node, env);
  67
  68         pred = skip_Proj(node);
  69         if (is_CallBegin(pred)            ||
  70             get_irn_op(pred) == op_EndReg ||
  71             get_irn_op(pred) == op_EndExcept) {
  72                 current_ir_graph = get_irn_irg(pred);
  73         }
  74
  75         if (is_no_Block(node)) { /* not block */
  76                 irg_walk_cg(get_nodes_block(node), visited, irg_set, pre, post, env);
  77         }
  78
  79         if (is_Block(node)) { /* block */
  80                 for (i = get_irn_arity(node) - 1; i >= 0; --i) {
  81                         ir_node * exec = get_irn_n(node, i);
  82                         ir_node * pred = skip_Proj(exec);
  83                         if ((
  84                               !is_CallBegin(pred)           &&
  85                               get_irn_op(pred) != op_EndReg &&
  86                               get_irn_op(pred) != op_EndExcept
  87                             ) || pset_new_contains(irg_set, get_irn_irg(pred))) {
  88                                 irg_walk_cg(exec, visited, irg_set, pre, post, env);
  89                         }
  90                 }
  91         } else if (is_Filter(node)) { /* filter */
  92                 for (i = get_irn_arity(node) - 1; i >= 0; --i) {
  93                         ir_node * pred = get_irn_n(node, i);
  94                         if (is_Unknown(pred) || is_Bad(pred)) {
  95                                 irg_walk_cg(pred, visited, irg_set, pre, post, env);
  96                         } else {
  97                                 ir_node * exec;
  98                                 exec = skip_Proj(get_Block_cfgpred(get_nodes_block(node), i));
  99
 100                                 if (is_Bad(exec)) {
 101                                         continue;
 102                                 }
 103
 104                                 assert(is_CallBegin(exec)            ||
 105                                        get_irn_op(exec) == op_EndReg ||
 106                                        get_irn_op(exec) == op_EndExcept);
 107                                 if (pset_new_contains(irg_set, get_irn_irg(exec))) {
 108                                         current_ir_graph = get_irn_irg(exec);
 109                                         irg_walk_cg(pred, visited, irg_set, pre, post, env);
 110                                         current_ir_graph = rem;
 111                                 }
 112                         }
 113                 }
 114         } else {                      /* everything else */
 115                 for (i = get_irn_arity(node) - 1; i >= 0; --i) {
 116                         irg_walk_cg(get_irn_n(node, i), visited, irg_set, pre, post, env);
 117                 }
 118         }
 119
 120         if (post) post(node, env);
 121
 122         current_ir_graph = rem;
 123 }
 124
 125
 126 /**
 127  * Insert all ir_graphs in irg_set, that are (transitive) reachable.
 128  */
 129 static void collect_irgs(ir_node * node, pset_new_t *irg_set) {
 130         if (is_Call(node)) {
 131                 int i;
 132                 for (i = get_Call_n_callees(node) - 1; i >= 0; --i) {
 133                         ir_entity * ent = get_Call_callee(node, i);
 134                         ir_graph * irg = get_entity_irg(ent);
 135                         if (irg && !pset_new_contains(irg_set, irg)) {
 136                                 pset_new_insert(irg_set, irg);
 137                                 irg_walk_graph(irg, (irg_walk_func *) collect_irgs, NULL, irg_set);
 138                         }
 139                 }
 140         }
 141 }
 142
 143 /**
 144  * specialized version of irg_walk_2, called if only pre callback exists
 145  *
 146  * @return number of visited nodes
 147  */
 148 static unsigned
 149 irg_walk_2_pre(ir_node *node, irg_walk_func *pre, void * env) {
 150         int i;
 151         unsigned cnt = 1;
 152         ir_graph *irg = current_ir_graph;
 153
 154         set_irn_visited(node, irg->visited);
 155
 156         pre(node, env);
 157
 158         if (node->op != op_Block) {
 159                 ir_node *pred = get_irn_n(node, -1);
 160                 if (pred->visited < irg->visited)
 161                         cnt += irg_walk_2_pre(pred, pre, env);
 162         }
 163         for (i = get_irn_arity(node) - 1; i >= 0; --i) {
 164                 ir_node *pred = get_irn_n(node, i);
 165                 if (pred->visited < irg->visited)
 166                         cnt += irg_walk_2_pre(pred, pre, env);
 167         }
 168         return cnt;
 169 }
 170
 171 /**
 172  * specialized version of irg_walk_2, called if only post callback exists
 173  *
 174  * @return number of visited nodes
 175  */
 176 static unsigned
 177 irg_walk_2_post(ir_node *node, irg_walk_func *post, void * env) {
 178         int i;
 179         unsigned cnt = 1;
 180         ir_graph *irg = current_ir_graph;
 181
 182         set_irn_visited(node, irg->visited);
 183
 184         if (node->op != op_Block) {
 185                 ir_node *pred = get_irn_n(node, -1);
 186                 if (pred->visited < irg->visited)
 187                         cnt += irg_walk_2_post(pred, post, env);
 188         }
 189         for (i = get_irn_arity(node) - 1; i >= 0; --i) {
 190                 ir_node *pred = get_irn_n(node, i);
 191                 if (pred->visited < irg->visited)
 192                         cnt += irg_walk_2_post(pred, post, env);
 193         }
 194
 195         post(node, env);
 196
 197         return cnt;
 198 }
 199
 200 /**
 201  * specialized version of irg_walk_2, called if pre and post callbacks exist
 202  *
 203  * @return number of visited nodes
 204  */
 205 static unsigned
 206 irg_walk_2_both(ir_node *node, irg_walk_func *pre, irg_walk_func *post, void * env) {
 207         int i;
 208         unsigned cnt = 1;
 209         ir_graph *irg = current_ir_graph;
 210
 211         set_irn_visited(node, irg->visited);
 212
 213         pre(node, env);
 214
 215         if (node->op != op_Block) {
 216                 ir_node *pred = get_irn_n(node, -1);
 217                 if (pred->visited < irg->visited)
 218                         cnt += irg_walk_2_both(pred, pre, post, env);
 219         }
 220         for (i = get_irn_arity(node) - 1; i >= 0; --i) {
 221                 ir_node *pred = get_irn_n(node, i);
 222                 if (pred->visited < irg->visited)
 223                         cnt += irg_walk_2_both(pred, pre, post, env);
 224         }
 225
 226         post(node, env);
 227
 228         return cnt;
 229 }
 230
 231 /**
 232  * Intraprozedural graph walker.
 233  *
 234  * @return number of visited nodes
 235  */
 236 static unsigned
 237 irg_walk_2(ir_node *node, irg_walk_func *pre, irg_walk_func *post, void * env)
 238 {
 239         if (node->visited < current_ir_graph->visited) {
 240                 if      (!post) return irg_walk_2_pre (node, pre, env);
 241                 else if (!pre)  return irg_walk_2_post(node, post, env);
 242                 else            return irg_walk_2_both(node, pre, post, env);
 243         }
 244         return 0;
 245 }
 246
 247 /* a counter */
 248 static unsigned nodes_touched = 0;
 249
 250 /*
 251  * generic graph walker
 252  */
 253 void irg_walk(ir_node *node, irg_walk_func *pre, irg_walk_func *post, void *env)
 254 {
 255         assert(is_ir_node(node));
 256
 257 #ifdef INTERPROCEDURAL_VIEW
 258         if (get_interprocedural_view()) {
 259                 pset_new_t           irg_set;
 260                 pset_new_iterator_t  iter;
 261                 ir_visited_t         visited;
 262                 ir_graph            *irg;
 263                 assert(get_irp_ip_view_state() == ip_view_valid);
 264
 265                 pset_new_init(&irg_set);
 266                 set_interprocedural_view(0);
 267                 pset_new_insert(&irg_set, current_ir_graph);
 268                 irg_walk(node, (irg_walk_func *) collect_irgs, NULL, &irg_set);
 269                 set_interprocedural_view(1);
 270                 visited = get_max_irg_visited() + 1;
 271
 272                 foreach_pset_new(&irg_set, irg, iter) {
 273                         set_irg_visited(irg, visited);
 274                 }
 275                 irg_walk_cg(node, visited, &irg_set, pre, post, env);
 276                 pset_new_destroy(&irg_set);
 277         } else {
 278 #endif
 279                 ir_reserve_resources(current_ir_graph, IR_RESOURCE_IRN_VISITED);
 280                 inc_irg_visited(current_ir_graph);
 281                 nodes_touched = irg_walk_2(node, pre, post, env);
 282                 ir_free_resources(current_ir_graph, IR_RESOURCE_IRN_VISITED);
 283 #ifdef INTERPROCEDURAL_VIEW
 284         }
 285 #endif
 286 }
 287
 288 /*
 289  * walk over a graph
 290  */
 291 void irg_walk_graph(ir_graph *irg, irg_walk_func *pre, irg_walk_func *post, void *env) {
 292         ir_graph * rem = current_ir_graph;
 293
 294         hook_irg_walk(irg, (generic_func *)pre, (generic_func *)post);
 295         current_ir_graph = irg;
 296         irg_walk(get_irg_end(irg), pre, post, env);
 297         irg->estimated_node_count = nodes_touched;
 298         current_ir_graph = rem;
 299 }
 300
 301 /* Executes irg_walk(end, pre, post, env) for all irgraphs in irprog.
 302    Sets current_ir_graph properly for each walk.  Conserves current
 303    current_ir_graph. */
 304 void all_irg_walk(irg_walk_func *pre, irg_walk_func *post, void *env) {
 305         int i, n;
 306         ir_graph *irg;
 307
 308         for (i = 0, n = get_irp_n_irgs(); i < n; i++) {
 309                 irg = get_irp_irg(i);
 310                 irg_walk_graph(irg, pre, post, env);
 311         }
 312 }
 313
 314 /***************************************************************************/
 315
 316 /**
 317  * specialized version of irg_walk_in_or_dep_2, called if only pre callback exists
 318  *
 319  * @return number of visited nodes
 320  */
 321 static unsigned
 322 irg_walk_in_or_dep_2_pre(ir_node *node, irg_walk_func *pre, void *env) {
 323         int i;
 324         unsigned cnt = 1;
 325         ir_graph *irg = current_ir_graph;
 326
 327         set_irn_visited(node, irg->visited);
 328
 329         pre(node, env);
 330
 331         if (node->op != op_Block) {
 332                 ir_node *pred = get_irn_n(node, -1);
 333                 if (pred->visited < irg->visited)
 334                         cnt += irg_walk_in_or_dep_2_pre(pred, pre, env);
 335         }
 336         for (i = get_irn_ins_or_deps(node) - 1; i >= 0; --i) {
 337                 ir_node *pred = get_irn_in_or_dep(node, i);
 338                 if (pred->visited < irg->visited)
 339                         cnt += irg_walk_in_or_dep_2_pre(pred, pre, env);
 340         }
 341         return cnt;
 342 }
 343
 344 /**
 345  * specialized version of irg_walk_in_or_dep_2, called if only post callback exists
 346  *
 347  * @return number of visited nodes
 348  */
 349 static unsigned
 350 irg_walk_in_or_dep_2_post(ir_node *node, irg_walk_func *post, void *env) {
 351         int i;
 352         unsigned cnt = 1;
 353         ir_graph *irg = current_ir_graph;
 354
 355         set_irn_visited(node, irg->visited);
 356
 357         if (node->op != op_Block) {
 358                 ir_node *pred = get_irn_n(node, -1);
 359                 if (pred->visited < irg->visited)
 360                         cnt += irg_walk_in_or_dep_2_post(pred, post, env);
 361         }
 362         for (i = get_irn_ins_or_deps(node) - 1; i >= 0; --i) {
 363                 ir_node *pred = get_irn_in_or_dep(node, i);
 364                 if (pred->visited < irg->visited)
 365                         cnt += irg_walk_in_or_dep_2_post(pred, post, env);
 366         }
 367
 368         post(node, env);
 369
 370         return cnt;
 371 }
 372
 373 /**
 374  * specialized version of irg_walk_in_or_dep_2, called if pre and post callbacks exist
 375  *
 376  * @return number of visited nodes
 377  */
 378 static unsigned
 379 irg_walk_in_or_dep_2_both(ir_node *node, irg_walk_func *pre, irg_walk_func *post, void *env) {
 380         int i;
 381         unsigned cnt = 1;
 382         ir_graph *irg = current_ir_graph;
 383
 384         set_irn_visited(node, irg->visited);
 385
 386         pre(node, env);
 387
 388         if (node->op != op_Block) {
 389                 ir_node *pred = get_irn_n(node, -1);
 390                 if (pred->visited < irg->visited)
 391                         cnt += irg_walk_in_or_dep_2_both(pred, pre, post, env);
 392         }
 393         for (i = get_irn_ins_or_deps(node) - 1; i >= 0; --i) {
 394                 ir_node *pred = get_irn_in_or_dep(node, i);
 395                 if (pred->visited < irg->visited)
 396                         cnt += irg_walk_in_or_dep_2_both(pred, pre, post, env);
 397         }
 398
 399         post(node, env);
 400
 401         return cnt;
 402 }
 403
 404 /**
 405  * Intraprozedural graph walker. Follows dependency edges as well.
 406  *
 407  * @return number of visited nodes
 408  */
 409 static unsigned
 410 irg_walk_in_or_dep_2(ir_node *node, irg_walk_func *pre, irg_walk_func *post, void *env)
 411 {
 412         if (node->visited < current_ir_graph->visited) {
 413                 if      (! post) return irg_walk_in_or_dep_2_pre (node, pre, env);
 414                 else if (! pre)  return irg_walk_in_or_dep_2_post(node, post, env);
 415                 else             return irg_walk_in_or_dep_2_both(node, pre, post, env);
 416         }
 417         return 0;
 418 }
 419
 420 /*
 421  * Generic graph walker. Follows dependency edges as well.
 422  */
 423 void irg_walk_in_or_dep(ir_node *node, irg_walk_func *pre, irg_walk_func *post, void *env)
 424 {
 425         assert(is_ir_node(node));
 426
 427         if (get_interprocedural_view()) {
 428                 assert(0 && "This is not yet implemented.");
 429         } else {
 430                 ir_reserve_resources(current_ir_graph, IR_RESOURCE_IRN_VISITED);
 431                 inc_irg_visited(current_ir_graph);
 432                 nodes_touched = irg_walk_in_or_dep_2(node, pre, post, env);
 433                 ir_free_resources(current_ir_graph, IR_RESOURCE_IRN_VISITED);
 434         }
 435 }
 436
 437 /*
 438  * Walk over a graph. Follow all edges (including dependencies)
 439  */
 440 void irg_walk_in_or_dep_graph(ir_graph *irg, irg_walk_func *pre, irg_walk_func *post, void *env) {
 441         ir_graph * rem = current_ir_graph;
 442
 443         hook_irg_walk(irg, (generic_func *)pre, (generic_func *)post);
 444         current_ir_graph = irg;
 445         irg_walk_in_or_dep(get_irg_end(irg), pre, post, env);
 446         irg->estimated_node_count = nodes_touched;
 447         current_ir_graph = rem;
 448 }
 449
 450 /***************************************************************************/
 451
 452 /**
 453  * Returns current_ir_graph and sets it to the irg of predecessor index
 454  * of node n.
 455  */
 456 static INLINE ir_graph *
 457 switch_irg(ir_node *n, int index) {
 458         ir_graph *old_current = current_ir_graph;
 459
 460         if (get_interprocedural_view()) {
 461                 /* Only Filter and Block nodes can have predecessors in other graphs. */
 462                 if (is_Filter(n))
 463                         n = get_nodes_block(n);
 464                 if (is_Block(n)) {
 465                         ir_node *cfop = skip_Proj(get_Block_cfgpred(n, index));
 466                         if (is_ip_cfop(cfop)) {
 467                                 current_ir_graph = get_irn_irg(cfop);
 468                         }
 469                 }
 470         }
 471
 472         return old_current;
 473 }
 474
 475 static void
 476 cg_walk_2(ir_node *node, irg_walk_func *pre, irg_walk_func *post, void * env)
 477 {
 478         int i;
 479         ir_graph *rem = NULL;
 480         assert(node);
 481
 482         if (get_irn_visited(node) < get_irg_visited(current_ir_graph)) {
 483                 set_irn_visited(node, get_irg_visited(current_ir_graph));
 484
 485                 if (pre) pre(node, env);
 486
 487                 if (is_no_Block(node))
 488                         cg_walk_2(get_nodes_block(node), pre, post, env);
 489                 for (i = get_irn_arity(node) - 1; i >= 0; --i) {
 490                         rem = switch_irg(node, i);  /* @@@ AS: Is this wrong? We do have to
 491                                                     switch to the irg of the predecessor, don't we? */
 492                         cg_walk_2(get_irn_n(node, i), pre, post, env);
 493                         current_ir_graph = rem;
 494                 }
 495
 496                 if (post) post(node, env);
 497         }
 498 }
 499
 500 #ifdef INTERPROCEDURAL_VIEW
 501 /* Walks all irgs in interprocedural view.  Visits each node only once. */
 502 void cg_walk(irg_walk_func *pre, irg_walk_func *post, void *env) {
 503         int i;
 504         ir_graph *rem = current_ir_graph;
 505         int rem_view = get_interprocedural_view();
 506
 507         set_interprocedural_view(1);
 508
 509         inc_max_irg_visited();
 510         /* Fix all irg_visited flags */
 511         for (i = 0; i < get_irp_n_irgs(); i++)
 512                 set_irg_visited(get_irp_irg(i), get_max_irg_visited());
 513
 514         /* Walk starting at unreachable procedures. Only these
 515          * have End blocks visible in interprocedural view. */
 516         for (i = 0; i < get_irp_n_irgs(); i++) {
 517                 ir_node *sb;
 518                 current_ir_graph = get_irp_irg(i);
 519
 520                 sb = get_irg_start_block(current_ir_graph);
 521
 522                 if ((get_Block_n_cfgpreds(sb) > 1) ||
 523                         (get_nodes_block(get_Block_cfgpred(sb, 0)) != sb)) continue;
 524
 525                 cg_walk_2(get_irg_end(current_ir_graph), pre, post, env);
 526         }
 527
 528         /* Check whether we walked all procedures: there could be procedures
 529            with cyclic calls but no call from the outside. */
 530         for (i = 0; i < get_irp_n_irgs(); i++) {
 531                 ir_node *sb;
 532                 current_ir_graph = get_irp_irg(i);
 533
 534                 /* Test start block: if inner procedure end and end block are not
 535                 * visible and therefore not marked. */
 536                 sb = get_irg_start_block(current_ir_graph);
 537                 if (get_irn_visited(sb) < get_irg_visited(current_ir_graph)) {
 538                         cg_walk_2(sb, pre, post, env);
 539                 }
 540         }
 541
 542         /* Walk all endless loops in inner procedures.
 543          * We recognize an inner procedure if the End node is not visited. */
 544         for (i = 0; i < get_irp_n_irgs(); i++) {
 545                 ir_node *e;
 546                 current_ir_graph = get_irp_irg(i);
 547                 e = get_irg_end(current_ir_graph);
 548                 if (get_irn_visited(e) < get_irg_visited(current_ir_graph)) {
 549                         int j;
 550                         /* Don't visit the End node. */
 551                         for (j = 0; j < get_End_n_keepalives(e); j++)
 552                                 cg_walk_2(get_End_keepalive(e, j), pre, post, env);
 553                 }
 554         }
 555
 556         set_interprocedural_view(rem_view);
 557         current_ir_graph = rem;
 558 }
 559 #endif
 560
 561
 562 /***************************************************************************/
 563
 564 /* Walks back from n until it finds a real cf op. */
 565 static ir_node *get_cf_op(ir_node *n) {
 566         while (!is_cfop(n) && !is_fragile_op(n) && !is_Bad(n)) {
 567                 n = skip_Id(n);
 568                 n = skip_Tuple(n);
 569                 n = skip_Proj(n);
 570         }
 571         return n;
 572 }
 573
 574 static void irg_block_walk_2(ir_node *node, irg_walk_func *pre, irg_walk_func *post, void *env)
 575 {
 576         int i;
 577
 578         if (!Block_block_visited(node)) {
 579                 mark_Block_block_visited(node);
 580
 581                 if(pre) pre(node, env);
 582
 583                 for(i = get_Block_n_cfgpreds(node) - 1; i >= 0; --i) {
 584                         /* find the corresponding predecessor block. */
 585                         ir_node *pred = get_cf_op(get_Block_cfgpred(node, i));
 586                         pred = get_nodes_block(pred);
 587                         if(get_irn_opcode(pred) == iro_Block) {
 588                                 /* recursion */
 589                                 irg_block_walk_2(pred, pre, post, env);
 590                         }
 591                         else {
 592                                 assert(get_irn_opcode(pred) == iro_Bad);
 593                         }
 594                 }
 595
 596                 if(post) post(node, env);
 597         }
 598 }
 599
 600
 601 /* walks only over Block nodes in the graph.  Has it's own visited
 602    flag, so that it can be interleaved with the other walker.         */
 603 void irg_block_walk(ir_node *node, irg_walk_func *pre, irg_walk_func *post, void *env)
 604 {
 605         ir_graph *irg = current_ir_graph;
 606         ir_node *block, *pred;
 607         int i;
 608
 609         hook_irg_block_walk(irg, node, (generic_func *)pre, (generic_func *)post);
 610
 611         assert(node);
 612         assert(!get_interprocedural_view());   /* interprocedural_view not implemented, because it
 613                                                * interleaves with irg_walk */
 614         ir_reserve_resources(irg, IR_RESOURCE_BLOCK_VISITED);
 615         inc_irg_block_visited(irg);
 616         block = is_Block(node) ? node : get_nodes_block(node);
 617         assert(is_Block(block));
 618         irg_block_walk_2(block, pre, post, env);
 619
 620         /* keepalive: the endless loops ... */
 621         if (is_End(node)) {
 622                 int arity = get_irn_arity(node);
 623                 for (i = 0; i < arity; i++) {
 624                         pred = get_irn_n(node, i);
 625                         if (is_Block(pred))
 626                                 irg_block_walk_2(pred, pre, post, env);
 627                 }
 628                 /* Sometimes the blocks died, but are still reachable through Phis.
 629                 * Make sure the algorithms that try to remove these reach them. */
 630                 for (i = 0; i < arity; i++) {
 631                         pred = get_irn_n(node, i);
 632                         if (get_irn_op(pred) == op_Phi) {
 633                                 ir_node *block = get_nodes_block(pred);
 634
 635                                 if (! is_Bad(block))
 636                                         irg_block_walk_2(block, pre, post, env);
 637                         }
 638                 }
 639         }
 640
 641         ir_free_resources(irg, IR_RESOURCE_BLOCK_VISITED);
 642 }
 643
 644 /*
 645  * walk over a graph block wise
 646  */
 647 void irg_block_walk_graph(ir_graph *irg, irg_walk_func *pre,
 648               irg_walk_func *post, void *env) {
 649         ir_graph * rem = current_ir_graph;
 650         current_ir_graph = irg;
 651         irg_block_walk(get_irg_end(irg), pre, post, env);
 652         current_ir_graph = rem;
 653 }
 654
 655 /*
 656  * Additionally walk over all anchors. Do NOT increase the visit flag.
 657  */
 658 void irg_walk_anchors(ir_graph *irg, irg_walk_func *pre, irg_walk_func *post, void *env) {
 659         ir_graph * rem = current_ir_graph;
 660         current_ir_graph = irg;
 661
 662         inc_irg_visited(irg);
 663         irg_walk_2(irg->anchor, pre, post, env);
 664
 665         current_ir_graph = rem;
 666 }
 667
 668 /********************************************************************/
 669
 670 typedef struct walk_env {
 671         irg_walk_func *pre;
 672         irg_walk_func *post;
 673         void *env;
 674 } walk_env;
 675
 676 static void walk_initializer(ir_initializer_t *initializer, walk_env *env)
 677 {
 678         switch(initializer->kind) {
 679     case IR_INITIALIZER_CONST:
 680         irg_walk(initializer->consti.value, env->pre, env->post, env->env);
 681         return;
 682     case IR_INITIALIZER_TARVAL:
 683     case IR_INITIALIZER_NULL:
 684         return;
 685
 686     case IR_INITIALIZER_COMPOUND: {
 687         size_t i;
 688         for(i = 0; i < initializer->compound.n_initializers; ++i) {
 689             ir_initializer_t *subinitializer
 690                 = initializer->compound.initializers[i];
 691             walk_initializer(subinitializer, env);
 692         }
 693         return;
 694     }
 695         }
 696         panic("invalid initializer found");
 697 }
 698
 699 /**
 700  * Walk to all constant expressions in this entity.
 701  */
 702 static void walk_entity(ir_entity *ent, void *env)
 703 {
 704         walk_env *my_env = (walk_env *)env;
 705
 706         if (get_entity_variability(ent) != variability_uninitialized) {
 707                 if (ent->has_initializer) {
 708                         walk_initializer(ent->attr.initializer, my_env);
 709                 } else if (is_atomic_entity(ent)) {
 710                         irg_walk(get_atomic_ent_value(ent), my_env->pre, my_env->post, my_env->env);
 711                 } else {
 712                         int i, n_vals = get_compound_ent_n_values(ent);
 713
 714                         for (i = 0; i < n_vals; i++)
 715                                 irg_walk(get_compound_ent_value(ent, i), my_env->pre, my_env->post, my_env->env);
 716                 }
 717         }
 718 }
 719
 720 /* Walks over all code in const_code_irg. */
 721 void walk_const_code(irg_walk_func *pre, irg_walk_func *post, void *env) {
 722         int i, j, n_types;
 723         walk_env my_env;
 724
 725         ir_graph *rem = current_ir_graph;
 726         current_ir_graph = get_const_code_irg();
 727         inc_irg_visited(current_ir_graph);
 728
 729         my_env.pre = pre;
 730         my_env.post = post;
 731         my_env.env = env;
 732
 733         /* Walk all types that can contain constant entities.  */
 734         walk_types_entities(get_glob_type(), &walk_entity, &my_env);
 735         n_types = get_irp_n_types();
 736         for (i = 0; i < n_types; i++)
 737                 walk_types_entities(get_irp_type(i), &walk_entity, &my_env);
 738         for (i = 0; i < get_irp_n_irgs(); i++)
 739                 walk_types_entities(get_irg_frame_type(get_irp_irg(i)), &walk_entity, &my_env);
 740
 741         /* Walk constant array bounds. */
 742         for (i = 0; i < n_types; i++) {
 743                 ir_type *tp = get_irp_type(i);
 744                 if (is_Array_type(tp)) {
 745                         int n_dim = get_array_n_dimensions(tp);
 746                         for (j = 0; j < n_dim; j++) {
 747                                 ir_node *n = get_array_lower_bound(tp, j);
 748                                 if (n) irg_walk(n, pre, post, env);
 749                                 n = get_array_upper_bound(tp, j);
 750                                 if (n) irg_walk(n, pre, post, env);
 751                         }
 752                 }
 753         }
 754
 755         current_ir_graph = rem;
 756 }