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  * @brief
  26  *  traverse an ir graph
  27  *  - execute the pre function before recursion
  28  *  - execute the post function after recursion
  29  */
  30 #include "config.h"
  31
  32 #include <stdlib.h>
  33
  34 #include "irnode_t.h"
  35 #include "irgraph_t.h"
  36 #include "irprog.h"
  37 #include "irgwalk.h"
  38 #include "irhooks.h"
  39 #include "ircgcons.h"
  40 #include "entity_t.h"
  41
  42 #include "error.h"
  43 #include "pset_new.h"
  44 #include "array.h"
  45
  46 #ifdef INTERPROCEDURAL_VIEW
  47 /**
  48  * Walk over an interprocedural graph (callgraph).
  49  * Visits only graphs in irg_set.
  50  */
  51 static void irg_walk_cg(ir_node * node, ir_visited_t visited,
  52                         pset_new_t *irg_set, irg_walk_func *pre,
  53                         irg_walk_func *post, void * env)
  54 {
  55         int i;
  56         ir_graph * rem = current_ir_graph;
  57         ir_node * pred;
  58
  59         assert(node && node->kind == k_ir_node);
  60         if (get_irn_visited(node) >= visited) return;
  61
  62         set_irn_visited(node, visited);
  63
  64         if (pre) pre(node, env);
  65
  66         pred = skip_Proj(node);
  67         if (is_CallBegin(pred)            ||
  68             get_irn_op(pred) == op_EndReg ||
  69             get_irn_op(pred) == op_EndExcept) {
  70                 current_ir_graph = get_irn_irg(pred);
  71         }
  72
  73         if (is_no_Block(node)) { /* not block */
  74                 irg_walk_cg(get_nodes_block(node), visited, irg_set, pre, post, env);
  75         }
  76
  77         if (is_Block(node)) { /* block */
  78                 for (i = get_irn_arity(node) - 1; i >= 0; --i) {
  79                         ir_node * exec = get_irn_n(node, i);
  80                         ir_node * pred = skip_Proj(exec);
  81                         if ((
  82                               !is_CallBegin(pred)           &&
  83                               get_irn_op(pred) != op_EndReg &&
  84                               get_irn_op(pred) != op_EndExcept
  85                             ) || pset_new_contains(irg_set, get_irn_irg(pred))) {
  86                                 irg_walk_cg(exec, visited, irg_set, pre, post, env);
  87                         }
  88                 }
  89         } else if (is_Filter(node)) { /* filter */
  90                 for (i = get_irn_arity(node) - 1; i >= 0; --i) {
  91                         ir_node * pred = get_irn_n(node, i);
  92                         if (is_Unknown(pred) || is_Bad(pred)) {
  93                                 irg_walk_cg(pred, visited, irg_set, pre, post, env);
  94                         } else {
  95                                 ir_node * exec;
  96                                 exec = skip_Proj(get_Block_cfgpred(get_nodes_block(node), i));
  97
  98                                 if (is_Bad(exec)) {
  99                                         continue;
 100                                 }
 101
 102                                 assert(is_CallBegin(exec)            ||
 103                                        get_irn_op(exec) == op_EndReg ||
 104                                        get_irn_op(exec) == op_EndExcept);
 105                                 if (pset_new_contains(irg_set, get_irn_irg(exec))) {
 106                                         current_ir_graph = get_irn_irg(exec);
 107                                         irg_walk_cg(pred, visited, irg_set, pre, post, env);
 108                                         current_ir_graph = rem;
 109                                 }
 110                         }
 111                 }
 112         } else {                      /* everything else */
 113                 for (i = get_irn_arity(node) - 1; i >= 0; --i) {
 114                         irg_walk_cg(get_irn_n(node, i), visited, irg_set, pre, post, env);
 115                 }
 116         }
 117
 118         if (post) post(node, env);
 119
 120         current_ir_graph = rem;
 121 }
 122
 123 /**
 124  * Insert all ir_graphs in irg_set, that are (transitive) reachable.
 125  */
 126 static void collect_irgs(ir_node * node, pset_new_t *irg_set)
 127 {
 128         if (is_Call(node)) {
 129                 int i;
 130                 for (i = get_Call_n_callees(node) - 1; i >= 0; --i) {
 131                         ir_entity * ent = get_Call_callee(node, i);
 132                         ir_graph * irg = get_entity_irg(ent);
 133                         if (irg && !pset_new_contains(irg_set, irg)) {
 134                                 pset_new_insert(irg_set, irg);
 135                                 irg_walk_graph(irg, (irg_walk_func *) collect_irgs, NULL, irg_set);
 136                         }
 137                 }
 138         }
 139 }
 140 #endif
 141
 142 /**
 143  * specialized version of irg_walk_2, called if only pre callback exists
 144  *
 145  * @return number of visited nodes
 146  */
 147 static unsigned
 148 irg_walk_2_pre(ir_node *node, irg_walk_func *pre, void * env)
 149 {
 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 {
 179         int i;
 180         unsigned cnt = 1;
 181         ir_graph *irg = current_ir_graph;
 182
 183         set_irn_visited(node, irg->visited);
 184
 185         if (node->op != op_Block) {
 186                 ir_node *pred = get_irn_n(node, -1);
 187                 if (pred->visited < irg->visited)
 188                         cnt += irg_walk_2_post(pred, post, env);
 189         }
 190         for (i = get_irn_arity(node) - 1; i >= 0; --i) {
 191                 ir_node *pred = get_irn_n(node, i);
 192                 if (pred->visited < irg->visited)
 193                         cnt += irg_walk_2_post(pred, post, env);
 194         }
 195
 196         post(node, env);
 197
 198         return cnt;
 199 }
 200
 201 /**
 202  * specialized version of irg_walk_2, called if pre and post callbacks exist
 203  *
 204  * @return number of visited nodes
 205  */
 206 static unsigned
 207 irg_walk_2_both(ir_node *node, irg_walk_func *pre, irg_walk_func *post, void * env)
 208 {
 209         int i;
 210         unsigned cnt = 1;
 211         ir_graph *irg = current_ir_graph;
 212
 213         set_irn_visited(node, irg->visited);
 214
 215         pre(node, env);
 216
 217         if (node->op != op_Block) {
 218                 ir_node *pred = get_irn_n(node, -1);
 219                 if (pred->visited < irg->visited)
 220                         cnt += irg_walk_2_both(pred, pre, post, env);
 221         }
 222         for (i = get_irn_arity(node) - 1; i >= 0; --i) {
 223                 ir_node *pred = get_irn_n(node, i);
 224                 if (pred->visited < irg->visited)
 225                         cnt += irg_walk_2_both(pred, pre, post, env);
 226         }
 227
 228         post(node, env);
 229
 230         return cnt;
 231 }
 232
 233 /**
 234  * Intraprozedural graph walker.
 235  *
 236  * @return number of visited nodes
 237  */
 238 unsigned irg_walk_2(ir_node *node, irg_walk_func *pre, irg_walk_func *post,
 239                     void *env)
 240 {
 241         if (node->visited < current_ir_graph->visited) {
 242                 if      (!post) return irg_walk_2_pre (node, pre, env);
 243                 else if (!pre)  return irg_walk_2_post(node, post, env);
 244                 else            return irg_walk_2_both(node, pre, post, env);
 245         }
 246         return 0;
 247 }
 248
 249 /* a counter */
 250 static unsigned nodes_touched = 0;
 251
 252 /*
 253  * generic graph walker
 254  */
 255 void irg_walk(ir_node *node, irg_walk_func *pre, irg_walk_func *post, void *env)
 256 {
 257         assert(is_ir_node(node));
 258
 259 #ifdef INTERPROCEDURAL_VIEW
 260         if (get_interprocedural_view()) {
 261                 pset_new_t           irg_set;
 262                 pset_new_iterator_t  iter;
 263                 ir_visited_t         visited;
 264                 ir_graph            *irg;
 265                 assert(get_irp_ip_view_state() == ip_view_valid);
 266
 267                 pset_new_init(&irg_set);
 268                 set_interprocedural_view(0);
 269                 pset_new_insert(&irg_set, current_ir_graph);
 270                 irg_walk(node, (irg_walk_func *) collect_irgs, NULL, &irg_set);
 271                 set_interprocedural_view(1);
 272                 visited = get_max_irg_visited() + 1;
 273
 274                 foreach_pset_new(&irg_set, irg, iter) {
 275                         set_irg_visited(irg, visited);
 276                 }
 277                 irg_walk_cg(node, visited, &irg_set, pre, post, env);
 278                 pset_new_destroy(&irg_set);
 279         } else {
 280 #endif
 281                 ir_reserve_resources(current_ir_graph, IR_RESOURCE_IRN_VISITED);
 282                 inc_irg_visited(current_ir_graph);
 283                 nodes_touched = irg_walk_2(node, pre, post, env);
 284                 ir_free_resources(current_ir_graph, IR_RESOURCE_IRN_VISITED);
 285 #ifdef INTERPROCEDURAL_VIEW
 286         }
 287 #endif
 288 }
 289
 290 /*
 291  * walk over a graph
 292  */
 293 void irg_walk_graph(ir_graph *irg, irg_walk_func *pre, irg_walk_func *post, void *env)
 294 {
 295         ir_graph * rem = current_ir_graph;
 296
 297         hook_irg_walk(irg, (generic_func *)pre, (generic_func *)post);
 298         current_ir_graph = irg;
 299         irg_walk(get_irg_end(irg), pre, post, env);
 300         irg->estimated_node_count = nodes_touched;
 301         current_ir_graph = rem;
 302 }
 303
 304 /* Executes irg_walk(end, pre, post, env) for all irgraphs in irprog.
 305    Sets current_ir_graph properly for each walk.  Conserves current
 306    current_ir_graph. */
 307 void all_irg_walk(irg_walk_func *pre, irg_walk_func *post, void *env)
 308 {
 309         int i, n;
 310         ir_graph *irg;
 311
 312         for (i = 0, n = get_irp_n_irgs(); i < n; i++) {
 313                 irg = get_irp_irg(i);
 314                 irg_walk_graph(irg, pre, post, env);
 315         }
 316 }
 317
 318 /***************************************************************************/
 319
 320 /**
 321  * specialized version of irg_walk_in_or_dep_2, called if only pre callback exists
 322  *
 323  * @return number of visited nodes
 324  */
 325 static unsigned
 326 irg_walk_in_or_dep_2_pre(ir_node *node, irg_walk_func *pre, void *env)
 327 {
 328         int i;
 329         unsigned cnt = 1;
 330         ir_graph *irg = current_ir_graph;
 331
 332         set_irn_visited(node, irg->visited);
 333
 334         pre(node, env);
 335
 336         if (node->op != op_Block) {
 337                 ir_node *pred = get_irn_n(node, -1);
 338                 if (pred->visited < irg->visited)
 339                         cnt += irg_walk_in_or_dep_2_pre(pred, pre, env);
 340         }
 341         for (i = get_irn_ins_or_deps(node) - 1; i >= 0; --i) {
 342                 ir_node *pred = get_irn_in_or_dep(node, i);
 343                 if (pred->visited < irg->visited)
 344                         cnt += irg_walk_in_or_dep_2_pre(pred, pre, env);
 345         }
 346         return cnt;
 347 }
 348
 349 /**
 350  * specialized version of irg_walk_in_or_dep_2, called if only post callback exists
 351  *
 352  * @return number of visited nodes
 353  */
 354 static unsigned
 355 irg_walk_in_or_dep_2_post(ir_node *node, irg_walk_func *post, void *env)
 356 {
 357         int i;
 358         unsigned cnt = 1;
 359         ir_graph *irg = current_ir_graph;
 360
 361         set_irn_visited(node, irg->visited);
 362
 363         if (node->op != op_Block) {
 364                 ir_node *pred = get_irn_n(node, -1);
 365                 if (pred->visited < irg->visited)
 366                         cnt += irg_walk_in_or_dep_2_post(pred, post, env);
 367         }
 368         for (i = get_irn_ins_or_deps(node) - 1; i >= 0; --i) {
 369                 ir_node *pred = get_irn_in_or_dep(node, i);
 370                 if (pred->visited < irg->visited)
 371                         cnt += irg_walk_in_or_dep_2_post(pred, post, env);
 372         }
 373
 374         post(node, env);
 375
 376         return cnt;
 377 }
 378
 379 /**
 380  * specialized version of irg_walk_in_or_dep_2, called if pre and post callbacks exist
 381  *
 382  * @return number of visited nodes
 383  */
 384 static unsigned
 385 irg_walk_in_or_dep_2_both(ir_node *node, irg_walk_func *pre, irg_walk_func *post, void *env)
 386 {
 387         int i;
 388         unsigned cnt = 1;
 389         ir_graph *irg = current_ir_graph;
 390
 391         set_irn_visited(node, irg->visited);
 392
 393         pre(node, env);
 394
 395         if (node->op != op_Block) {
 396                 ir_node *pred = get_irn_n(node, -1);
 397                 if (pred->visited < irg->visited)
 398                         cnt += irg_walk_in_or_dep_2_both(pred, pre, post, env);
 399         }
 400         for (i = get_irn_ins_or_deps(node) - 1; i >= 0; --i) {
 401                 ir_node *pred = get_irn_in_or_dep(node, i);
 402                 if (pred->visited < irg->visited)
 403                         cnt += irg_walk_in_or_dep_2_both(pred, pre, post, env);
 404         }
 405
 406         post(node, env);
 407
 408         return cnt;
 409 }
 410
 411 /**
 412  * Intraprozedural graph walker. Follows dependency edges as well.
 413  *
 414  * @return number of visited nodes
 415  */
 416 static unsigned
 417 irg_walk_in_or_dep_2(ir_node *node, irg_walk_func *pre, irg_walk_func *post, void *env)
 418 {
 419         if (node->visited < current_ir_graph->visited) {
 420                 if      (! post) return irg_walk_in_or_dep_2_pre (node, pre, env);
 421                 else if (! pre)  return irg_walk_in_or_dep_2_post(node, post, env);
 422                 else             return irg_walk_in_or_dep_2_both(node, pre, post, env);
 423         }
 424         return 0;
 425 }
 426
 427 /*
 428  * Generic graph walker. Follows dependency edges as well.
 429  */
 430 void irg_walk_in_or_dep(ir_node *node, irg_walk_func *pre, irg_walk_func *post, void *env)
 431 {
 432         assert(is_ir_node(node));
 433
 434         if (get_interprocedural_view()) {
 435                 assert(0 && "This is not yet implemented.");
 436         } else {
 437                 ir_reserve_resources(current_ir_graph, IR_RESOURCE_IRN_VISITED);
 438                 inc_irg_visited(current_ir_graph);
 439                 nodes_touched = irg_walk_in_or_dep_2(node, pre, post, env);
 440                 ir_free_resources(current_ir_graph, IR_RESOURCE_IRN_VISITED);
 441         }
 442 }
 443
 444 /*
 445  * Walk over a graph. Follow all edges (including dependencies)
 446  */
 447 void irg_walk_in_or_dep_graph(ir_graph *irg, irg_walk_func *pre, irg_walk_func *post, void *env)
 448 {
 449         ir_graph * rem = current_ir_graph;
 450
 451         hook_irg_walk(irg, (generic_func *)pre, (generic_func *)post);
 452         current_ir_graph = irg;
 453         irg_walk_in_or_dep(get_irg_end(irg), pre, post, env);
 454         irg->estimated_node_count = nodes_touched;
 455         current_ir_graph = rem;
 456 }
 457
 458 /***************************************************************************/
 459
 460 /**
 461  * Returns current_ir_graph and sets it to the irg of predecessor index
 462  * of node n.
 463  */
 464 static inline ir_graph *
 465 switch_irg(ir_node *n, int index)
 466 {
 467         ir_graph *old_current = current_ir_graph;
 468
 469         if (get_interprocedural_view()) {
 470                 /* Only Filter and Block nodes can have predecessors in other graphs. */
 471                 if (is_Filter(n))
 472                         n = get_nodes_block(n);
 473                 if (is_Block(n)) {
 474                         ir_node *cfop = skip_Proj(get_Block_cfgpred(n, index));
 475                         if (is_ip_cfop(cfop)) {
 476                                 current_ir_graph = get_irn_irg(cfop);
 477                         }
 478                 }
 479         }
 480
 481         return old_current;
 482 }
 483
 484 #ifdef INTERPROCEDURAL_VIEW
 485 static void
 486 cg_walk_2(ir_node *node, irg_walk_func *pre, irg_walk_func *post, void * env)
 487 {
 488         int i;
 489         ir_graph *rem = NULL;
 490         assert(node);
 491
 492         if (get_irn_visited(node) < get_irg_visited(current_ir_graph)) {
 493                 set_irn_visited(node, get_irg_visited(current_ir_graph));
 494
 495                 if (pre) pre(node, env);
 496
 497                 if (is_no_Block(node))
 498                         cg_walk_2(get_nodes_block(node), pre, post, env);
 499                 for (i = get_irn_arity(node) - 1; i >= 0; --i) {
 500                         rem = switch_irg(node, i);  /* @@@ AS: Is this wrong? We do have to
 501                                                     switch to the irg of the predecessor, don't we? */
 502                         cg_walk_2(get_irn_n(node, i), pre, post, env);
 503                         current_ir_graph = rem;
 504                 }
 505
 506                 if (post) post(node, env);
 507         }
 508 }
 509
 510 /* Walks all irgs in interprocedural view.  Visits each node only once. */
 511 void cg_walk(irg_walk_func *pre, irg_walk_func *post, void *env)
 512 {
 513         int i;
 514         ir_graph *rem = current_ir_graph;
 515         int rem_view = get_interprocedural_view();
 516
 517         set_interprocedural_view(1);
 518
 519         inc_max_irg_visited();
 520         /* Fix all irg_visited flags */
 521         for (i = 0; i < get_irp_n_irgs(); i++)
 522                 set_irg_visited(get_irp_irg(i), get_max_irg_visited());
 523
 524         /* Walk starting at unreachable procedures. Only these
 525          * have End blocks visible in interprocedural view. */
 526         for (i = 0; i < get_irp_n_irgs(); i++) {
 527                 ir_node *sb;
 528                 current_ir_graph = get_irp_irg(i);
 529
 530                 sb = get_irg_start_block(current_ir_graph);
 531
 532                 if ((get_Block_n_cfgpreds(sb) > 1) ||
 533                         (get_nodes_block(get_Block_cfgpred(sb, 0)) != sb)) continue;
 534
 535                 cg_walk_2(get_irg_end(current_ir_graph), pre, post, env);
 536         }
 537
 538         /* Check whether we walked all procedures: there could be procedures
 539            with cyclic calls but no call from the outside. */
 540         for (i = 0; i < get_irp_n_irgs(); i++) {
 541                 ir_node *sb;
 542                 current_ir_graph = get_irp_irg(i);
 543
 544                 /* Test start block: if inner procedure end and end block are not
 545                 * visible and therefore not marked. */
 546                 sb = get_irg_start_block(current_ir_graph);
 547                 if (get_irn_visited(sb) < get_irg_visited(current_ir_graph)) {
 548                         cg_walk_2(sb, pre, post, env);
 549                 }
 550         }
 551
 552         /* Walk all endless loops in inner procedures.
 553          * We recognize an inner procedure if the End node is not visited. */
 554         for (i = 0; i < get_irp_n_irgs(); i++) {
 555                 ir_node *e;
 556                 current_ir_graph = get_irp_irg(i);
 557                 e = get_irg_end(current_ir_graph);
 558                 if (get_irn_visited(e) < get_irg_visited(current_ir_graph)) {
 559                         int j;
 560                         /* Don't visit the End node. */
 561                         for (j = 0; j < get_End_n_keepalives(e); j++)
 562                                 cg_walk_2(get_End_keepalive(e, j), pre, post, env);
 563                 }
 564         }
 565
 566         set_interprocedural_view(rem_view);
 567         current_ir_graph = rem;
 568 }
 569 #endif
 570
 571
 572 /***************************************************************************/
 573
 574 /* Walks back from n until it finds a real cf op. */
 575 static ir_node *get_cf_op(ir_node *n)
 576 {
 577         while (!is_cfop(n) && !is_fragile_op(n) && !is_Bad(n)) {
 578                 n = skip_Id(n);
 579                 n = skip_Tuple(n);
 580                 n = skip_Proj(n);
 581         }
 582         return n;
 583 }
 584
 585 static void irg_block_walk_2(ir_node *node, irg_walk_func *pre, irg_walk_func *post, void *env)
 586 {
 587         int i;
 588
 589         if (!Block_block_visited(node)) {
 590                 mark_Block_block_visited(node);
 591
 592                 if (pre) pre(node, env);
 593
 594                 for (i = get_Block_n_cfgpreds(node) - 1; i >= 0; --i) {
 595                         /* find the corresponding predecessor block. */
 596                         ir_node *pred = get_cf_op(get_Block_cfgpred(node, i));
 597                         pred = get_nodes_block(pred);
 598                         if (get_irn_opcode(pred) == iro_Block) {
 599                                 /* recursion */
 600                                 irg_block_walk_2(pred, pre, post, env);
 601                         }
 602                         else {
 603                                 assert(get_irn_opcode(pred) == iro_Bad);
 604                         }
 605                 }
 606
 607                 if (post) post(node, env);
 608         }
 609 }
 610
 611
 612 /* walks only over Block nodes in the graph.  Has it's own visited
 613    flag, so that it can be interleaved with the other walker.         */
 614 void irg_block_walk(ir_node *node, irg_walk_func *pre, irg_walk_func *post, void *env)
 615 {
 616         ir_graph *irg = current_ir_graph;
 617         ir_node *block, *pred;
 618         int i;
 619
 620         hook_irg_block_walk(irg, node, (generic_func *)pre, (generic_func *)post);
 621
 622         assert(node);
 623         assert(!get_interprocedural_view());   /* interprocedural_view not implemented, because it
 624                                                 * interleaves with irg_walk */
 625         ir_reserve_resources(irg, IR_RESOURCE_BLOCK_VISITED);
 626         inc_irg_block_visited(irg);
 627         block = is_Block(node) ? node : get_nodes_block(node);
 628         assert(is_Block(block));
 629         irg_block_walk_2(block, pre, post, env);
 630
 631         /* keepalive: the endless loops ... */
 632         if (is_End(node)) {
 633                 int arity = get_irn_arity(node);
 634                 for (i = 0; i < arity; i++) {
 635                         pred = get_irn_n(node, i);
 636                         if (!is_Block(pred)) {
 637                                 pred = get_nodes_block(pred);
 638                                 if (!is_Block(pred)) {
 639                                         /* if rare cases a kept node might have a bad block input */
 640                                         continue;
 641                                 }
 642                         }
 643                         /* Sometimes the blocks died, but are still reachable through kept nodes.
 644                          * Make sure the algorithms that try to remove these reach them. */
 645                         irg_block_walk_2(pred, pre, post, env);
 646                 }
 647         }
 648
 649         ir_free_resources(irg, IR_RESOURCE_BLOCK_VISITED);
 650 }
 651
 652 /*
 653  * walk over a graph block wise
 654  */
 655 void irg_block_walk_graph(ir_graph *irg, irg_walk_func *pre,
 656               irg_walk_func *post, void *env) {
 657         ir_graph * rem = current_ir_graph;
 658         current_ir_graph = irg;
 659         irg_block_walk(get_irg_end(irg), pre, post, env);
 660         current_ir_graph = rem;
 661 }
 662
 663 /*
 664  * Additionally walk over all anchors. Do NOT increase the visit flag.
 665  */
 666 void irg_walk_anchors(ir_graph *irg, irg_walk_func *pre, irg_walk_func *post, void *env)
 667 {
 668         ir_graph * rem = current_ir_graph;
 669         current_ir_graph = irg;
 670
 671         inc_irg_visited(irg);
 672         irg_walk_2(irg->anchor, pre, post, env);
 673
 674         current_ir_graph = rem;
 675 }
 676
 677 /********************************************************************/
 678
 679 typedef struct walk_env {
 680         irg_walk_func *pre;
 681         irg_walk_func *post;
 682         void *env;
 683 } walk_env;
 684
 685 static void walk_initializer(ir_initializer_t *initializer, walk_env *env)
 686 {
 687         switch (initializer->kind) {
 688     case IR_INITIALIZER_CONST:
 689         irg_walk(initializer->consti.value, env->pre, env->post, env->env);
 690         return;
 691     case IR_INITIALIZER_TARVAL:
 692     case IR_INITIALIZER_NULL:
 693         return;
 694
 695     case IR_INITIALIZER_COMPOUND: {
 696         size_t i;
 697         for (i = 0; i < initializer->compound.n_initializers; ++i) {
 698             ir_initializer_t *subinitializer
 699                 = initializer->compound.initializers[i];
 700             walk_initializer(subinitializer, env);
 701         }
 702         return;
 703     }
 704         }
 705         panic("invalid initializer found");
 706 }
 707
 708 /**
 709  * Walk to all constant expressions in this entity.
 710  */
 711 static void walk_entity(ir_entity *ent, void *env)
 712 {
 713         walk_env *my_env = (walk_env *)env;
 714
 715         if (ent->initializer != NULL) {
 716                 walk_initializer(ent->initializer, my_env);
 717         } else if (entity_has_compound_ent_values(ent)) {
 718                 int i, n_vals = get_compound_ent_n_values(ent);
 719
 720                 for (i = 0; i < n_vals; i++)
 721                         irg_walk(get_compound_ent_value(ent, i), my_env->pre, my_env->post, my_env->env);
 722         }
 723 }
 724
 725 /* Walks over all code in const_code_irg. */
 726 void walk_const_code(irg_walk_func *pre, irg_walk_func *post, void *env)
 727 {
 728         int i, j, n_types;
 729         walk_env my_env;
 730         ir_segment_t s;
 731
 732         ir_graph *rem = current_ir_graph;
 733         current_ir_graph = get_const_code_irg();
 734         inc_irg_visited(current_ir_graph);
 735
 736         my_env.pre = pre;
 737         my_env.post = post;
 738         my_env.env = env;
 739
 740         /* Walk all types that can contain constant entities.  */
 741         for (s = IR_SEGMENT_FIRST; s <= IR_SEGMENT_LAST; s++)
 742                 walk_types_entities(get_segment_type(s), &walk_entity, &my_env);
 743         n_types = get_irp_n_types();
 744         for (i = 0; i < n_types; i++)
 745                 walk_types_entities(get_irp_type(i), &walk_entity, &my_env);
 746         for (i = 0; i < get_irp_n_irgs(); i++)
 747                 walk_types_entities(get_irg_frame_type(get_irp_irg(i)), &walk_entity, &my_env);
 748
 749         /* Walk constant array bounds. */
 750         for (i = 0; i < n_types; i++) {
 751                 ir_type *tp = get_irp_type(i);
 752                 if (is_Array_type(tp)) {
 753                         int n_dim = get_array_n_dimensions(tp);
 754                         for (j = 0; j < n_dim; j++) {
 755                                 ir_node *n = get_array_lower_bound(tp, j);
 756                                 if (n) irg_walk(n, pre, post, env);
 757                                 n = get_array_upper_bound(tp, j);
 758                                 if (n) irg_walk(n, pre, post, env);
 759                         }
 760                 }
 761         }
 762
 763         current_ir_graph = rem;
 764 }