2 * Copyright (C) 1995-2008 University of Karlsruhe. All right reserved.
4 * This file is part of libFirm.
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.
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.
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
22 * @brief Structure Analysis
23 * @author Michael Beck
29 #include "firm_common.h"
31 #include "structure.h"
41 typedef union ir_reg_or_blk ir_reg_or_blk;
43 /* The structure tree. */
45 struct obstack obst; /**< The obstack where the data is allocated. */
46 ir_region *top; /**< The top region. */
47 ir_graph *irg; /**< Associated graph. */
52 firm_kind kind; /**< Must be k_ir_region. */
53 ir_region_kind type; /**< The type of this region. */
54 ir_region *parent; /**< points to the parent. */
55 ir_reg_or_blk *parts; /**< The list of all region parts. */
56 ir_region **pred; /**< The predecessor (control flow) regions of this region. */
57 ir_region **succ; /**< The successor (control flow) regions of this region. */
58 unsigned prenum; /**< DFS pre-oder number */
59 unsigned postnum; /**< DFS post-oder number */
60 void *link; /**< A link field. */
61 unsigned long nr; /**< for debugging */
62 unsigned visited:1; /**< The visited flag. */
63 unsigned exit:1; /**< If set, the parent region can be left by this node. */
64 unsigned enter:1; /**< If set, the parent region can be entered by this node. */
67 /* A helper type for unioning blocks and regions. */
69 firm_kind *kind; /**< For easier check. */
70 ir_node *blk; /**< A node */
71 ir_region *region; /**< A region. */
74 /* The debug handle. */
75 DEBUG_ONLY(static firm_dbg_module_t *dbg;)
78 * Returns the link of a region.
80 void *get_region_link(const ir_region *reg)
86 * Sets the link of a region.
88 void set_region_link(ir_region *reg, void *data)
94 * Get the immediate region of a block.
96 ir_region *get_block_region(const ir_node *block)
98 assert(is_Block(block));
99 return block->attr.block.region;
103 * Sets the immediate region of a block.
105 void set_block_region(ir_node *block, ir_region *reg)
107 assert(is_Block(block));
108 block->attr.block.region = reg;
112 * Get the immediate region of a node.
114 ir_region *get_irn_region(ir_node *n)
117 n = get_nodes_block(n);
118 return get_block_region(n);
122 * Return non-zero if a given firm thing is a region.
124 int is_region(const void *thing)
126 const firm_kind *kind = (const firm_kind*) thing;
127 return *kind == k_ir_region;
131 * Return the number of predecessors of a region.
133 int get_region_n_preds(const ir_region *reg)
135 return ARR_LEN(reg->pred);
139 * Return the predecessor region at position pos.
141 ir_region *get_region_pred(const ir_region *reg, int pos)
143 assert(0 <= pos && pos <= get_region_n_preds(reg));
144 return reg->pred[pos];
148 * Set the predecessor region at position pos.
150 void set_region_pred(ir_region *reg, int pos, ir_region *n)
152 assert(0 <= pos && pos <= get_region_n_preds(reg));
157 * Return the number of successors in a region.
159 int get_region_n_succs(const ir_region *reg)
161 return ARR_LEN(reg->succ);
165 * Return the successor region at position pos.
167 ir_region *get_region_succ(const ir_region *reg, int pos)
169 assert(0 <= pos && pos <= get_region_n_succs(reg));
170 return reg->succ[pos];
174 * Set the successor region at position pos.
176 void set_region_succ(ir_region *reg, int pos, ir_region *n)
178 assert(0 <= pos && pos <= get_region_n_succs(reg));
182 /* ----------------------- construction -------------------------- */
184 /** Walker environment. */
185 typedef struct walk_env {
186 struct obstack *obst; /**< An obstack to allocate from. */
187 ir_region **post; /**< The list of all currently existent top regions. */
188 unsigned l_post; /**< The length of the allocated regions array. */
189 unsigned premax; /**< maximum pre counter */
190 unsigned postmax; /**< maximum post counter */
191 ir_node *start_block; /**< The start block of the graph. */
192 ir_node *end_block; /**< The end block of the graph. */
196 * Do a DFS search on the initial regions, assign a prenum and a postnum to every
197 * node and store the region nodes into the post array.
199 static void dfs_walk2(ir_region *reg, walk_env *env)
203 if (reg->visited == 0) {
206 reg->prenum = env->premax++;
207 for (i = 0, n = get_region_n_succs(reg); i < n; ++i) {
209 ir_region *succ = get_region_succ(reg, i);
210 dfs_walk2(succ, env);
213 env->post[env->postmax] = reg;
214 reg->postnum = env->postmax++;
219 * Do a DFS search on the initial regions, assign a prenum and a postnum to every
220 * node and store the region nodes into the post array.
222 static void dfs_walk(ir_graph *irg, walk_env *env)
224 ir_graph *rem = current_ir_graph;
227 current_ir_graph = irg;
228 reg = (ir_region*) get_irn_link(get_irg_start_block(irg));
233 current_ir_graph = rem;
237 * Post-walker: wrap all blocks with a BasicBlock region
240 static void wrap_BasicBlocks(ir_node *block, void *ctx)
242 walk_env *env = (walk_env*) ctx;
245 /* Allocate a Block wrapper */
246 reg = OALLOC(env->obst, ir_region);
247 reg->kind = k_ir_region;
248 reg->type = ir_rk_BasicBlock;
256 reg->nr = get_irn_node_nr(block);
257 reg->parts = NEW_ARR_D(ir_reg_or_blk, env->obst, 1);
259 reg->parts[0].blk = block;
260 set_irn_link(block, reg);
263 } /* wrap_BasicBlocks */
266 * Post-walker: Create the pred and succ edges for Block wrapper.
267 * Kill edges to the Start and End blocks.
269 static void update_BasicBlock_regions(ir_node *blk, void *ctx)
271 walk_env *env = (walk_env*) ctx;
272 ir_region *reg = (ir_region*) get_irn_link(blk);
275 if (blk == env->start_block) {
276 /* handle Firm's self loop: Start block has no predecessors */
277 reg->pred = NEW_ARR_D(ir_region *, env->obst, 0);
279 len = get_Block_n_cfgpreds(blk);
280 reg->pred = NEW_ARR_D(ir_region *, env->obst, len);
281 for (i = j = 0; i < len; ++i) {
282 ir_node *pred = get_Block_cfgpred_block(blk, i);
283 reg->pred[j++] = (ir_region*) get_irn_link(pred);
285 ARR_SHRINKLEN(reg->pred, j);
288 len = get_Block_n_cfg_outs(blk);
289 reg->succ = NEW_ARR_D(ir_region *, env->obst, len);
290 for (i = j = 0; i < len; ++i) {
291 ir_node *succ = get_Block_cfg_out(blk, i);
292 reg->succ[j++] = (ir_region*) get_irn_link(succ);
294 ARR_SHRINKLEN(reg->succ, j);
295 } /* update_BasicBlock_regions */
297 /** Allocate a new region on an obstack */
298 #define ALLOC_REG(obst, reg, tp) \
300 (reg) = OALLOC((obst), ir_region); \
301 (reg)->kind = k_ir_region; \
303 (reg)->parent = NULL; \
305 (reg)->postnum = 0; \
306 (reg)->visited = 0; \
309 (reg)->link = NULL; \
313 * Creates a new Sequence region.
315 static ir_region *new_Sequence(struct obstack *obst, ir_region *nset, int nset_len)
317 ir_region *reg, *next;
320 ALLOC_REG(obst, reg, ir_rk_Sequence);
322 reg->parts = NEW_ARR_D(ir_reg_or_blk, obst, nset_len);
324 /* beware: list is in reverse order, reverse */
326 for (i = nset_len - 1; i >= 0; --i) {
328 reg->parts[i].region = nset;
330 next = (ir_region*) nset->link;
334 reg->nr = reg->parts[0].region->nr;
335 reg->pred = DUP_ARR_D(ir_region *, obst, reg->parts[0].region->pred);
336 reg->succ = DUP_ARR_D(ir_region *, obst, reg->parts[nset_len - 1].region->succ);
339 DB((dbg, LEVEL_2, " Created Sequence "));
340 for (i = 0; i < nset_len; ++i) {
341 DB((dbg, LEVEL_2, "(%u)", reg->parts[i].region->nr));
343 DB((dbg, LEVEL_2, "\n"));
349 * Create a new IfThenElse region.
351 static ir_region *new_IfThenElse(struct obstack *obst, ir_region *if_b, ir_region *then_b, ir_region *else_b)
355 ALLOC_REG(obst, reg, ir_rk_IfThenElse);
358 reg->parts = NEW_ARR_D(ir_reg_or_blk, obst, 3);
360 reg->parts[0].region = if_b; if_b->parent = reg;
361 reg->parts[1].region = then_b; then_b->parent = reg;
362 reg->parts[2].region = else_b; else_b->parent = reg;
364 reg->pred = DUP_ARR_D(ir_region *, obst, if_b->pred);
365 reg->succ = DUP_ARR_D(ir_region *, obst, then_b->succ);
367 DB((dbg, LEVEL_2, " Created If(%u)Then(%u)Else(%u)\n", reg->nr, then_b->nr, else_b->nr));
370 } /* new_IfThenElse */
373 * Create a new IfThen region.
375 static ir_region *new_IfThen(struct obstack *obst, ir_region *if_b, ir_region *then_b)
379 ALLOC_REG(obst, reg, ir_rk_IfThen);
382 reg->parts = NEW_ARR_D(ir_reg_or_blk, obst, 2);
384 reg->parts[0].region = if_b; if_b->parent = reg;
385 reg->parts[1].region = then_b; then_b->parent = reg;
387 reg->pred = DUP_ARR_D(ir_region *, obst, if_b->pred);
388 reg->succ = DUP_ARR_D(ir_region *, obst, then_b->succ);
390 DB((dbg, LEVEL_2, " Created If(%u)Then(%u)\n", reg->nr, then_b->nr));
393 } /* new_IfThenElse */
396 * Create a new Switch/case region.
398 static ir_region *new_SwitchCase(struct obstack *obst, ir_region_kind type, ir_region *head, ir_region *exit,
399 ir_region *cases, int cases_len)
401 ir_region *reg, *c, *n;
405 /* check, if the exit block is in the list */
406 for (c = cases; c != NULL; c = (ir_region*) c->link) {
413 ALLOC_REG(obst, reg, type);
416 reg->parts = NEW_ARR_D(ir_reg_or_blk, obst, cases_len + add);
418 reg->parts[0].region = head; head->parent = reg;
420 for (c = cases; c != NULL; c = n) {
421 n = (ir_region*) c->link;
423 reg->parts[i++].region = c;
429 reg->pred = DUP_ARR_D(ir_region *, obst, head->pred);
430 reg->succ = NEW_ARR_D(ir_region *, obst, 1);
434 DB((dbg, LEVEL_2, " Created %s(%u)\n", reg->type == ir_rk_Switch ? "Switch" : "Case", reg->nr));
435 for (i = 1; i < ARR_LEN(reg->parts); ++i) {
436 DB((dbg, LEVEL_2, " Case(%u)\n", reg->parts[i].region->nr));
438 DB((dbg, LEVEL_2, " Exit(%u)\n", exit->nr));
441 } /* new_SwitchCase */
444 * Create a new SelfLoop region.
446 static ir_region *new_SelfLoop(struct obstack *obst, ir_region *head)
448 ir_region *reg, *succ;
451 ALLOC_REG(obst, reg, ir_rk_SelfLoop);
454 reg->parts = NEW_ARR_D(ir_reg_or_blk, obst, 1);
456 reg->parts[0].region = head; head->parent = reg;
458 len = ARR_LEN(head->pred);
459 reg->pred = NEW_ARR_D(ir_region *, obst, len - 1);
460 for (i = j = 0; i < len; ++i) {
461 ir_region *pred = get_region_pred(head, i);
463 reg->pred[j++] = pred;
465 assert(j == len - 1);
467 reg->succ = NEW_ARR_D(ir_region *, obst, 1);
468 assert(ARR_LEN(head->succ) == 2);
470 succ = get_region_succ(head, 0);
474 reg->succ[0] = get_region_succ(head, 1);
476 DB((dbg, LEVEL_2, " Created SelfLoop(%u)\n", reg->nr));
482 * Create a new RepeatLoop region.
484 static ir_region *new_RepeatLoop(struct obstack *obst, ir_region *head, ir_region *body)
486 ir_region *reg, *succ;
488 ALLOC_REG(obst, reg, ir_rk_RepeatLoop);
491 reg->parts = NEW_ARR_D(ir_reg_or_blk, obst, 2);
493 reg->parts[0].region = head; head->parent = reg;
494 reg->parts[1].region = body; body->parent = reg;
496 reg->pred = DUP_ARR_D(ir_region *, obst, head->pred);
497 reg->succ = NEW_ARR_D(ir_region *, obst, 1);
498 assert(ARR_LEN(body->succ) == 2);
500 succ = get_region_succ(body, 0);
504 reg->succ[0] = get_region_succ(body, 1);
506 DB((dbg, LEVEL_2, " Created RepeatLoop(%u)Body(%u)\n", reg->nr, body->nr));
509 } /* new_RepeatLoop */
512 * Create a new WhileLoop region.
514 static ir_region *new_WhileLoop(struct obstack *obst, ir_region *head)
516 ir_region *reg, *succ;
517 ir_region *body = (ir_region*) head->link;
522 ALLOC_REG(obst, reg, ir_rk_WhileLoop);
525 reg->parts = NEW_ARR_D(ir_reg_or_blk, obst, 2);
527 reg->parts[0].region = head; head->parent = reg;
528 reg->parts[1].region = body; body->parent = reg;
530 len = ARR_LEN(head->pred);
531 reg->pred = NEW_ARR_D(ir_region *, obst, len - 1);
532 for (i = j = 0; i < len; ++i) {
533 ir_region *pred = get_region_pred(head, i);
535 reg->pred[j++] = pred;
537 assert(j == len - 1);
539 reg->succ = NEW_ARR_D(ir_region *, obst, 1);
540 assert(ARR_LEN(head->succ) == 2);
542 succ = get_region_succ(head, 0);
546 reg->succ[0] = get_region_succ(head, 1);
548 DB((dbg, LEVEL_2, " Created WhileLoop(%u)Body(%u)\n", reg->nr, body->nr));
551 } /* new_WhileLoop */
554 * Create a new new_NaturalLoop region.
556 static ir_region *new_NaturalLoop(struct obstack *obst, ir_region *head)
558 ir_region *reg, *c, *n;
559 int i, j, k, len, n_pred, n_succ;
561 /* count number of parts */
562 for (len = 0, c = head; c != NULL; c = (ir_region*) c->link)
565 ALLOC_REG(obst, reg, ir_rk_WhileLoop);
568 reg->parts = NEW_ARR_D(ir_reg_or_blk, obst, len);
570 /* enter all parts */
571 for (i = 0, c = head; c != NULL; c = n) {
572 reg->parts[i++].region = c;
574 n = (ir_region*) c->link;
578 /* count number of preds */
580 for (i = get_region_n_preds(head) - 1; i >= 0; --i) {
581 ir_region *pred = get_region_pred(head, i);
582 if (pred->parent != reg)
585 reg->pred = NEW_ARR_D(ir_region *, obst, n_pred);
586 for (j = 0, i = get_region_n_preds(head) - 1; i >= 0; --i) {
587 ir_region *pred = get_region_pred(head, i);
588 if (pred->parent != reg)
589 reg->pred[j++] = pred;
592 /* count number of succs */
594 for (j = 0; j < len; ++j) {
595 ir_region *pc = reg->parts[j].region;
596 for (i = get_region_n_succs(pc) - 1; i >= 0; --i) {
597 ir_region *succ = get_region_succ(pc, i);
598 if (succ->parent != reg)
602 reg->succ = NEW_ARR_D(ir_region *, obst, n_succ);
604 for (j = 0; j < len; ++j) {
605 ir_region *pc = reg->parts[j].region;
606 for (i = get_region_n_succs(pc) - 1; i >= 0; --i) {
607 ir_region *succ = get_region_succ(pc, i);
608 if (succ->parent != reg)
609 reg->succ[k++] = succ;
614 DB((dbg, LEVEL_2, " Created NaturalLoop(%u)Head(%u)\n", reg->nr, head->nr));
615 for (i = 1; i < len; ++i) {
616 ir_region *p = reg->parts[i].region;
617 DB((dbg, LEVEL_2, " Body(%u)\n", p->nr));
621 } /* new_NaturalLoop */
624 * Return true if region a is an ancestor of region b in DFS search.
626 static int is_ancestor(const ir_region *a, const ir_region *b)
628 return (a->prenum <= b->prenum && a->postnum > b->postnum);
632 * Return true if region pred is a predecessor of region n.
634 static int pred_of(const ir_region *pred, const ir_region *n)
637 for (i = get_region_n_preds(n) - 1; i >= 0; --i) {
638 if (get_region_pred(n, i) == pred)
645 * Return true if region succ is a successor of region n.
647 static int succ_of(const ir_region *succ, const ir_region *n)
650 for (i = get_region_n_succs(n) - 1; i >= 0; --i) {
651 if (get_region_succ(n, i) == succ)
658 * Reverse a linked list of regions.
660 static struct ir_region *reverse_list(ir_region *n)
662 ir_region *prev = NULL, *next;
664 for (; n; n = next) {
665 next = (ir_region*) n->link;
673 * Find the cyclic region in the subgraph entered by node.
675 static ir_region *find_cyclic_region(ir_region *node)
678 ir_region *last = node;
681 for (i = get_region_n_preds(node) - 1; i >= 0; --i) {
682 ir_region *pred = get_region_pred(node, i);
684 /* search backedges */
685 if (!pred->link && pred != last && is_ancestor(node, pred)) {
686 ir_region *rem = last;
691 for (j = get_region_n_preds(pred) - 1; j >= 0; --j) {
692 ir_region *p = get_region_pred(pred, j);
694 /* Search regions we didn't visited yet and
695 link them into the list. */
696 if (!p->link && p != last) {
697 if (is_ancestor(node, p)) {
705 /* reverse the list. */
706 last = (ir_region*) rem->link;
707 rem->link = reverse_list((ir_region*) rem->link);
711 if (node->link && improper) {
712 /* found an improper region, do minimization */
718 #define LINK(list) ((ir_region *)list->link)
721 * Detect a cyclic region.
723 static ir_region *cyclic_region_type(struct obstack *obst, ir_region *node)
727 /* simple cases first */
728 if (succ_of(node, node)) {
729 return new_SelfLoop(obst, node);
731 if (get_region_n_succs(node) == 1) {
732 ir_region *succ = get_region_succ(node, 0);
733 if (get_region_n_preds(succ) == 1 && succ_of(node, succ)) {
734 return new_RepeatLoop(obst, node, succ);
737 list = find_cyclic_region(node);
740 if (!LINK(list)->link && get_region_n_succs((ir_region*) list->link) == 1) {
741 /* only one body block with only one successor (the head) */
742 return new_WhileLoop(obst, list);
744 /* A Loop with one head */
745 return new_NaturalLoop(obst, list);
752 * Clear all links on a list. Needed, because we expect cleared links.
754 static void clear_list(ir_region *list)
758 for (next = list; next; list = next) {
759 next = (ir_region*) list->link;
764 #define ADD_LIST(list, n) do { n->link = list; list = n; ++list##_len; } while (0)
767 * Detect an acyclic region.
769 static ir_region *acyclic_region_type(struct obstack *obst, ir_region *node)
773 ir_region *nset = NULL;
777 /* check for a block containing node */
779 p = get_region_n_preds(n) == 1;
782 n = get_region_pred(n, 0);
783 p = get_region_n_preds(n) == 1;
784 s = get_region_n_succs(n) == 1;
787 s = get_region_n_succs(n) == 1;
790 n = get_region_succ(n, 0);
791 p = get_region_n_preds(n) == 1;
792 s = get_region_n_succs(n) == 1;
798 /* node --> .. --> .. */
799 res = new_Sequence(obst, nset, nset_len);
804 /* check for IfThenElse */
805 k = get_region_n_succs(node);
807 int n_succs, m_succs, n_preds, m_preds;
809 n = get_region_succ(node, 0);
810 m = get_region_succ(node, 1);
812 n_succs = get_region_n_succs(n);
813 m_succs = get_region_n_succs(m);
814 n_preds = get_region_n_preds(n);
815 m_preds = get_region_n_preds(m);
816 if (n_succs == 1 && n_succs == m_succs && n_preds == m_preds &&
817 get_region_succ(n, 0) == get_region_succ(m, 0)) {
823 return new_IfThenElse(obst, node, n, m);
826 get_region_succ(n, 0) == m &&
832 return new_IfThen(obst, node, n);
835 get_region_succ(m, 0) == m &&
841 return new_IfThen(obst, node, m);
844 /* check for Switch, case */
846 ir_region *rexit = NULL;
847 nset = NULL; nset_len = 0;
849 for (i = k - 1; i >= 0; --i) {
850 n = get_region_succ(node, i);
852 if (get_region_n_succs(n) != 1) {
853 /* must be the exit */
861 ir_region_kind kind = ir_rk_Case;
862 ir_region *pos_exit_1 = NULL;
863 ir_region *pos_exit_2 = NULL;
866 for (m = (ir_region*) nset; m != NULL; m = (ir_region*) m->link) {
867 if (get_region_n_succs(m) != 1) {
868 /* must be the exit block */
871 } else if (rexit != m) {
877 ir_region *succ = get_region_succ(m, 0);
879 if (succ->link == NULL) {
881 if (succ == pos_exit_1)
883 else if (succ == pos_exit_2)
885 else if (pos_exit_1 == NULL)
887 else if (pos_exit_2 == NULL)
890 /* more than two possible exits */
893 } else if (rexit != succ) {
903 for (n = (ir_region*) nset; n != NULL; n = (ir_region*) n->link) {
906 /* good, default fall through */
909 succ = get_region_succ(n, 0);
911 /* good, switch to exit */
914 if (succ->link == NULL) {
925 return new_SwitchCase(obst, kind, node, rexit, nset, nset_len);
935 * replace all pred edges from region pred that points to any of the set set
936 * to ONE edge to reg.
938 static void replace_pred(ir_region *succ, ir_region *reg)
940 int i, len = get_region_n_preds(succ);
943 for (i = 0; i < len; ++i) {
944 ir_region *pred = get_region_pred(succ, i);
946 if (pred->parent == reg) {
951 r = get_region_pred(succ, --len);
957 set_region_pred(succ, i, r);
959 /* the current region can be entered by this node */
963 ARR_SHRINKLEN(succ->pred, len);
967 * replace all succ edges from region pred that points to any of the set set
968 * to ONE edge to reg.
970 static void replace_succ(ir_region *pred, ir_region *reg)
972 int i, len = get_region_n_succs(pred);
975 for (i = 0; i < len; ++i) {
976 ir_region *succ = get_region_succ(pred, i);
978 if (succ->parent == reg) {
983 r = get_region_succ(pred, --len);
989 set_region_succ(pred, i, r);
991 /* current region can be left by this node */
995 ARR_SHRINKLEN(pred->succ, len);
999 * Reduce the graph by the node reg.
1001 static void reduce(walk_env *env, ir_region *reg)
1004 ir_region *head = reg->parts[0].region;
1005 unsigned maxorder = head->postnum;
1006 unsigned minorder = head->prenum;
1008 /* second step: replace all preds in successors */
1009 for (i = get_region_n_succs(reg) - 1; i >= 0; --i) {
1010 ir_region *succ = get_region_succ(reg, i);
1012 replace_pred(succ, reg);
1015 /* third step: replace all succs in predessors */
1016 for (i = get_region_n_preds(reg) - 1; i >= 0; --i) {
1017 ir_region *pred = get_region_pred(reg, i);
1019 replace_succ(pred, reg);
1022 reg->prenum = minorder;
1023 reg->postnum = maxorder;
1024 env->post[maxorder] = reg;
1028 * Construct the region tree of a graph by doing
1029 * structural analysis.
1031 * Uses link fields of nodes.
1033 * @param irg the graph
1035 ir_reg_tree *construct_region_tree(ir_graph *irg)
1038 ir_graph *rem = current_ir_graph;
1039 ir_reg_tree *res = XMALLOC(ir_reg_tree);
1041 obstack_init(&res->obst);
1043 current_ir_graph = irg;
1045 FIRM_DBG_REGISTER(dbg, "firm.ana.structure");
1046 firm_dbg_set_mask(dbg, SET_LEVEL_5);
1048 DB((dbg, LEVEL_1, "Structural analysis on %+F starts...\n", irg));
1050 /* we need dominance info */
1053 assure_irg_outs(irg);
1055 env.start_block = get_irg_start_block(irg);
1056 env.end_block = get_irg_end_block(irg);
1058 /* create the Block wrapper and count them */
1060 env.obst = &res->obst;
1061 irg_block_walk_graph(irg, NULL, wrap_BasicBlocks, &env);
1062 irg_block_walk_graph(irg, NULL, update_BasicBlock_regions, &env);
1064 env.post = NEW_ARR_F(ir_region *, env.l_post);
1066 /* do the DFS walk */
1067 dfs_walk(irg, &env);
1069 DB((dbg, LEVEL_1, "%d regions left\n", env.postmax));
1070 if (env.postmax > 1) {
1071 unsigned postctr = 0;
1073 ir_region *reg, *n = env.post[postctr];
1075 if (n->parent != NULL) {
1076 /* already folded */
1079 /* locate an acyclic region if present */
1080 reg = acyclic_region_type(env.obst, n);
1082 /* locate a cyclic region */
1083 reg = cyclic_region_type(env.obst, n);
1086 /* found a new region */
1090 } while (reg != NULL);
1092 } while (postctr < env.postmax);
1094 DB((dbg, LEVEL_1, "Structural analysis finished.\n"));
1096 DEL_ARR_F(env.post);
1097 current_ir_graph = rem;
1099 res->top = env.post[0];
1105 * Walk over the region tree.
1107 * @param reg a region node
1108 * @param pre walker function, executed before the children of a tree node are visited
1109 * @param post walker function, executed after the children of a tree node are visited
1110 * @param env environment, passed to pre and post
1112 static void region_tree_walk2(ir_region *reg, irg_reg_walk_func *pre, irg_reg_walk_func *post, void *env)
1118 if (reg->type != ir_rk_BasicBlock) {
1119 for (i = 0, n = ARR_LEN(reg->parts); i < n; ++i)
1120 region_tree_walk2(reg->parts[i].region, pre, post, env);
1127 * Walk over the region tree.
1129 * @param tree the tree
1130 * @param pre walker function, executed before the children of a tree node are visited
1131 * @param post walker function, executed after the children of a tree node are visited
1132 * @param env environment, passed to pre and post
1134 void region_tree_walk(ir_reg_tree *tree, irg_reg_walk_func *pre, irg_reg_walk_func *post, void *env)
1136 region_tree_walk2(tree->top, pre, post, env);