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