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