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 Construct and access dominator / post dominator tree.
23 * @author Goetz Lindenmaier, Michael Beck, Rubino Geiss
24 * @date 2.2002
25 */
26 #include "config.h"
27
28 #include <string.h>
29
30 #include "irouts.h"
31
32 #include "xmalloc.h"
33 #include "irgwalk.h"
34 #include "irdom_t.h"
35 #include "irgraph_t.h"
36 #include "irnode_t.h"
37 #include "ircons_t.h"
38 #include "array_t.h"
39 #include "iredges.h"
40
41
42 #define get_dom_info(bl) (&(bl)->attr.block.dom)
43 #define get_pdom_info(bl) (&(bl)->attr.block.pdom)
44
get_Block_idom(const ir_node * bl)45 ir_node *get_Block_idom(const ir_node *bl)
46 {
47 assert(is_Block(bl));
48 if (get_Block_dom_depth(bl) == -1) {
49 /* This block is not reachable from Start */
50 ir_graph *irg = get_irn_irg(bl);
51 return new_r_Bad(irg, mode_BB);
52 }
53 return get_dom_info(bl)->idom;
54 }
55
set_Block_idom(ir_node * bl,ir_node * n)56 void set_Block_idom(ir_node *bl, ir_node *n)
57 {
58 ir_dom_info *bli = get_dom_info(bl);
59
60 assert(is_Block(bl));
61
62 /* Set the immediate dominator of bl to n */
63 bli->idom = n;
64
65 /*
66 * If we don't set the root of the dominator tree
67 * Append bl to the dominates queue of n.
68 */
69 if (n != NULL) {
70 ir_dom_info *ni = get_dom_info(n);
71
72 bli->next = ni->first;
73 ni->first = bl;
74 }
75 }
76
get_Block_ipostdom(const ir_node * bl)77 ir_node *get_Block_ipostdom(const ir_node *bl)
78 {
79 assert(is_Block(bl));
80 if (get_Block_postdom_depth(bl) == -1) {
81 /* This block is not reachable from Start */
82 ir_graph *irg = get_irn_irg(bl);
83 return new_r_Bad(irg, mode_BB);
84 }
85 return get_pdom_info(bl)->idom;
86 }
87
set_Block_ipostdom(ir_node * bl,ir_node * n)88 void set_Block_ipostdom(ir_node *bl, ir_node *n)
89 {
90 ir_dom_info *bli = get_pdom_info(bl);
91
92 assert(is_Block(bl));
93
94 /* Set the immediate post dominator of bl to n */
95 bli->idom = n;
96
97 /*
98 * If we don't set the root of the post dominator tree
99 * Append bl to the post dominates queue of n.
100 */
101 if (n != NULL) {
102 ir_dom_info *ni = get_pdom_info(n);
103
104 bli->next = ni->first;
105 ni->first = bl;
106 }
107 }
108
get_Block_dom_pre_num(const ir_node * bl)109 int get_Block_dom_pre_num(const ir_node *bl)
110 {
111 assert(is_Block(bl));
112 return get_dom_info(bl)->pre_num;
113 }
114
set_Block_dom_pre_num(ir_node * bl,int num)115 void set_Block_dom_pre_num(ir_node *bl, int num)
116 {
117 assert(is_Block(bl));
118 get_dom_info(bl)->pre_num = num;
119 }
120
get_Block_dom_depth(const ir_node * bl)121 int get_Block_dom_depth(const ir_node *bl)
122 {
123 assert(is_Block(bl));
124 return get_dom_info(bl)->dom_depth;
125 }
126
set_Block_dom_depth(ir_node * bl,int depth)127 void set_Block_dom_depth(ir_node *bl, int depth)
128 {
129 assert(is_Block(bl));
130 get_dom_info(bl)->dom_depth = depth;
131 }
132
133
get_Block_postdom_pre_num(const ir_node * bl)134 int get_Block_postdom_pre_num(const ir_node *bl)
135 {
136 assert(is_Block(bl));
137 return get_pdom_info(bl)->pre_num;
138 }
139
set_Block_postdom_pre_num(ir_node * bl,int num)140 void set_Block_postdom_pre_num(ir_node *bl, int num)
141 {
142 assert(is_Block(bl));
143 get_pdom_info(bl)->pre_num = num;
144 }
145
get_Block_postdom_depth(const ir_node * bl)146 int get_Block_postdom_depth(const ir_node *bl)
147 {
148 assert(is_Block(bl));
149 return get_pdom_info(bl)->dom_depth;
150 }
151
set_Block_postdom_depth(ir_node * bl,int depth)152 void set_Block_postdom_depth(ir_node *bl, int depth)
153 {
154 assert(is_Block(bl));
155 get_pdom_info(bl)->dom_depth = depth;
156 }
157
get_Block_dom_tree_pre_num(const ir_node * bl)158 unsigned get_Block_dom_tree_pre_num(const ir_node *bl)
159 {
160 assert(is_Block(bl));
161 return get_dom_info(bl)->tree_pre_num;
162 }
163
get_Block_dom_max_subtree_pre_num(const ir_node * bl)164 unsigned get_Block_dom_max_subtree_pre_num(const ir_node *bl)
165 {
166 assert(is_Block(bl));
167 return get_dom_info(bl)->max_subtree_pre_num;
168 }
169
get_Block_pdom_tree_pre_num(const ir_node * bl)170 unsigned get_Block_pdom_tree_pre_num(const ir_node *bl)
171 {
172 assert(is_Block(bl));
173 return get_pdom_info(bl)->tree_pre_num;
174 }
175
get_Block_pdom_max_subtree_pre_num(const ir_node * bl)176 unsigned get_Block_pdom_max_subtree_pre_num(const ir_node *bl)
177 {
178 assert(is_Block(bl));
179 return get_pdom_info(bl)->max_subtree_pre_num;
180 }
181
block_dominates(const ir_node * a,const ir_node * b)182 int block_dominates(const ir_node *a, const ir_node *b)
183 {
184 const ir_dom_info *ai, *bi;
185
186 if (is_Block(a) && is_Block(b)) {
187 ai = get_dom_info(a);
188 bi = get_dom_info(b);
189 return bi->tree_pre_num - ai->tree_pre_num
190 <= ai->max_subtree_pre_num - ai->tree_pre_num;
191 }
192
193 return 0;
194 }
195
block_strictly_dominates(const ir_node * a,const ir_node * b)196 int block_strictly_dominates(const ir_node *a, const ir_node *b)
197 {
198 return (a != b) && block_dominates(a, b);
199 }
200
node_smallest_common_dominator(ir_node * a,ir_node * b)201 ir_node *node_smallest_common_dominator(ir_node *a, ir_node *b)
202 {
203 ir_node *bl_a = is_Block(a) ? a : get_nodes_block(a);
204 ir_node *bl_b = is_Block(b) ? b : get_nodes_block(b);
205 ir_node *dom_bl = NULL;
206
207 /* Check if block of a dominates block of b */
208 if (block_dominates(bl_a, bl_b))
209 dom_bl = bl_a;
210 /* Check if block of b dominates block of a */
211 else if (block_dominates(bl_b, bl_a))
212 dom_bl = bl_b;
213 else {
214 /* walk up dominator tree and search for first block dominating a and b */
215 while (! dom_bl) {
216 bl_a = get_Block_idom(bl_a);
217
218 assert(! is_Bad(bl_a) && "block is dead?");
219
220 if (block_dominates(bl_a, bl_b))
221 dom_bl = bl_a;
222 }
223 }
224
225 return dom_bl;
226 }
227
228 /* Get the first node in the list of nodes dominated by a given block. */
get_Block_dominated_first(const ir_node * bl)229 ir_node *get_Block_dominated_first(const ir_node *bl)
230 {
231 assert(is_Block(bl));
232 return get_dom_info(bl)->first;
233 }
234
get_Block_dominated_next(const ir_node * bl)235 ir_node *get_Block_dominated_next(const ir_node *bl)
236 {
237 assert(is_Block(bl));
238 return get_dom_info(bl)->next;
239 }
240
block_postdominates(const ir_node * a,const ir_node * b)241 int block_postdominates(const ir_node *a, const ir_node *b)
242 {
243 const ir_dom_info *ai, *bi;
244
245 if (is_Block(a) && is_Block(b)) {
246 ai = get_pdom_info(a);
247 bi = get_pdom_info(b);
248 return bi->tree_pre_num - ai->tree_pre_num
249 <= ai->max_subtree_pre_num - ai->tree_pre_num;
250 }
251
252 return 0;
253 }
254
block_strictly_postdominates(const ir_node * a,const ir_node * b)255 int block_strictly_postdominates(const ir_node *a, const ir_node *b)
256 {
257 return (a != b) && block_postdominates(a, b);
258 }
259
get_Block_postdominated_first(const ir_node * bl)260 ir_node *get_Block_postdominated_first(const ir_node *bl)
261 {
262 assert(is_Block(bl));
263 return get_pdom_info(bl)->first;
264 }
265
get_Block_postdominated_next(const ir_node * bl)266 ir_node *get_Block_postdominated_next(const ir_node *bl)
267 {
268 assert(is_Block(bl));
269 return get_pdom_info(bl)->next;
270 }
271
dom_tree_walk(ir_node * bl,irg_walk_func * pre,irg_walk_func * post,void * env)272 void dom_tree_walk(ir_node *bl, irg_walk_func *pre,
273 irg_walk_func *post, void *env)
274 {
275 ir_node *p;
276
277 if (pre)
278 pre(bl, env);
279
280 dominates_for_each(bl, p) {
281 dom_tree_walk(p, pre, post, env);
282 }
283
284 if (post)
285 post(bl, env);
286 }
287
postdom_tree_walk(ir_node * bl,irg_walk_func * pre,irg_walk_func * post,void * env)288 void postdom_tree_walk(ir_node *bl, irg_walk_func *pre,
289 irg_walk_func *post, void *env)
290 {
291 ir_node *p;
292
293 if (pre)
294 pre(bl, env);
295
296 postdominates_for_each(bl, p) {
297 postdom_tree_walk(p, pre, post, env);
298 }
299
300 if (post)
301 post(bl, env);
302 }
303
dom_tree_walk_irg(ir_graph * irg,irg_walk_func * pre,irg_walk_func * post,void * env)304 void dom_tree_walk_irg(ir_graph *irg, irg_walk_func *pre,
305 irg_walk_func *post, void *env)
306 {
307 /* The root of the dominator tree should be the Start block. */
308 ir_node *root = get_irg_start_block(irg);
309
310 assert(irg_has_properties(irg, IR_GRAPH_PROPERTY_CONSISTENT_DOMINANCE)
311 && "The dominators of the irg must be consistent");
312 assert(root && "The start block of the graph is NULL?");
313 assert(get_dom_info(root)->idom == NULL
314 && "The start node in the graph must be the root of the dominator tree");
315 dom_tree_walk(root, pre, post, env);
316 }
317
postdom_tree_walk_irg(ir_graph * irg,irg_walk_func * pre,irg_walk_func * post,void * env)318 void postdom_tree_walk_irg(ir_graph *irg, irg_walk_func *pre,
319 irg_walk_func *post, void *env)
320 {
321 /* The root of the post dominator tree should be the End block. */
322 ir_node *root = get_irg_end_block(irg);
323
324 assert(irg_has_properties(irg, IR_GRAPH_PROPERTY_CONSISTENT_POSTDOMINANCE)
325 && "The dominators of the irg must be consistent");
326 assert(root && "The end block of the graph is NULL?");
327 assert(get_pdom_info(root)->idom == NULL
328 && "The End block node in the graph must be the root of the post dominator tree");
329 postdom_tree_walk(root, pre, post, env);
330 }
331
332
assign_tree_dom_pre_order(ir_node * bl,void * data)333 static void assign_tree_dom_pre_order(ir_node *bl, void *data)
334 {
335 unsigned *num = (unsigned*) data;
336 ir_dom_info *bi = get_dom_info(bl);
337
338 bi->tree_pre_num = (*num)++;
339 }
340
assign_tree_dom_pre_order_max(ir_node * bl,void * data)341 static void assign_tree_dom_pre_order_max(ir_node *bl, void *data)
342 {
343 ir_dom_info *bi = get_dom_info(bl);
344 ir_node *p;
345 unsigned max = 0;
346 unsigned children = 0;
347 (void) data;
348
349 for (p = bi->first; p; p = get_dom_info(p)->next) {
350 unsigned max_p = get_dom_info(p)->max_subtree_pre_num;
351 max = max > max_p ? max : max_p;
352 children++;
353 }
354
355 bi->max_subtree_pre_num = children > 0 ? max : bi->tree_pre_num;
356 assert(bi->max_subtree_pre_num >= bi->tree_pre_num);
357 }
358
assign_tree_postdom_pre_order(ir_node * bl,void * data)359 static void assign_tree_postdom_pre_order(ir_node *bl, void *data)
360 {
361 unsigned *num = (unsigned*) data;
362 ir_dom_info *bi = get_pdom_info(bl);
363
364 bi->tree_pre_num = (*num)++;
365 }
366
assign_tree_postdom_pre_order_max(ir_node * bl,void * data)367 static void assign_tree_postdom_pre_order_max(ir_node *bl, void *data)
368 {
369 ir_dom_info *bi = get_pdom_info(bl);
370 ir_node *p;
371 unsigned max = 0;
372 unsigned children = 0;
373 (void) data;
374
375 for (p = bi->first; p; p = get_pdom_info(p)->next) {
376 unsigned max_p = get_pdom_info(p)->max_subtree_pre_num;
377 max = max > max_p ? max : max_p;
378 children++;
379 }
380
381 bi->max_subtree_pre_num = children > 0 ? max : bi->tree_pre_num;
382 assert(bi->max_subtree_pre_num >= bi->tree_pre_num);
383 }
384
385 /**
386 * count the number of blocks and clears the post dominance info
387 */
count_and_init_blocks_pdom(ir_node * bl,void * env)388 static void count_and_init_blocks_pdom(ir_node *bl, void *env)
389 {
390 int *n_blocks = (int *) env;
391
392 (*n_blocks) ++;
393
394 memset(get_pdom_info(bl), 0, sizeof(ir_dom_info));
395 set_Block_ipostdom(bl, NULL);
396 set_Block_postdom_pre_num(bl, -1);
397 set_Block_postdom_depth(bl, -1);
398 }
399
400 /** temporary type used while constructing the dominator / post dominator tree. */
401 typedef struct tmp_dom_info {
402 ir_node *block; /**< backlink */
403
404 struct tmp_dom_info *semi; /**< semidominator */
405 struct tmp_dom_info *parent;
406 struct tmp_dom_info *label; /**< used for LINK and EVAL */
407 struct tmp_dom_info *ancestor;/**< used for LINK and EVAL */
408 struct tmp_dom_info *dom; /**< After step 3, if the semidominator of w is
409 its immediate dominator, then w->dom is the
410 immediate dominator of w. Otherwise w->dom
411 is a vertex v whose number is smaller than
412 w and whose immediate dominator is also w's
413 immediate dominator. After step 4, w->dom
414 is the immediate dominator of w. */
415 struct tmp_dom_info *bucket; /**< set of vertices with same semidominator */
416 } tmp_dom_info;
417
418 /** Struct to pass info through walker. */
419 typedef struct {
420 tmp_dom_info *d;
421 int used;
422 } dom_env;
423
424
425 /**
426 * Walks Blocks along the out data structure. If recursion started with
427 * Start block misses control dead blocks.
428 */
init_tmp_dom_info(ir_node * bl,tmp_dom_info * parent,tmp_dom_info * tdi_list,int * used,int n_blocks)429 static void init_tmp_dom_info(ir_node *bl, tmp_dom_info *parent,
430 tmp_dom_info *tdi_list, int *used, int n_blocks)
431 {
432 tmp_dom_info *tdi;
433 int i;
434
435 assert(is_Block(bl));
436 if (Block_block_visited(bl))
437 return;
438 mark_Block_block_visited(bl);
439 set_Block_dom_pre_num(bl, *used);
440
441 assert(*used < n_blocks);
442 tdi = &tdi_list[*used];
443 ++(*used);
444
445 tdi->semi = tdi;
446 tdi->label = tdi;
447 tdi->ancestor = NULL;
448 tdi->bucket = NULL;
449 tdi->parent = parent;
450 tdi->block = bl;
451
452 /* Iterate */
453 for (i = get_Block_n_cfg_outs_ka(bl) - 1; i >= 0; --i) {
454 ir_node *pred = get_Block_cfg_out_ka(bl, i);
455 /* can happen for half-optimized dead code (I've seen this in student
456 projects */
457 if (!is_Block(pred))
458 continue;
459
460 init_tmp_dom_info(pred, tdi, tdi_list, used, n_blocks);
461 }
462 }
463
464 /**
465 * Walks Blocks along the control flow. If recursion started with
466 * End block misses blocks in endless loops.
467 */
init_tmp_pdom_info(ir_node * bl,tmp_dom_info * parent,tmp_dom_info * tdi_list,int * used,int n_blocks)468 static void init_tmp_pdom_info(ir_node *bl, tmp_dom_info *parent,
469 tmp_dom_info *tdi_list, int* used, int n_blocks)
470 {
471 tmp_dom_info *tdi;
472 int i;
473
474 assert(is_Block(bl));
475 if (get_irg_block_visited(current_ir_graph) == get_Block_block_visited(bl))
476 return;
477 mark_Block_block_visited(bl);
478 set_Block_postdom_pre_num(bl, *used);
479
480 assert(*used < n_blocks);
481 tdi = &tdi_list[*used];
482 ++(*used);
483
484 tdi->semi = tdi;
485 tdi->label = tdi;
486 tdi->ancestor = NULL;
487 tdi->bucket = NULL;
488 tdi->parent = parent;
489 tdi->block = bl;
490
491 /* Iterate */
492 for (i = get_Block_n_cfgpreds(bl) - 1; i >= 0; --i) {
493 ir_node *pred = get_Block_cfgpred_block(bl, i);
494 if (is_Bad(pred))
495 continue;
496 assert(is_Block(pred));
497 init_tmp_pdom_info(pred, tdi, tdi_list, used, n_blocks);
498 }
499
500 /* Handle keep-alives. Note that the preprocessing
501 in init_construction() had already killed all
502 phantom keep-alive edges. All remaining block keep-alives
503 are really edges to endless loops.
504 */
505 if (bl == get_irg_end_block(current_ir_graph)) {
506 ir_node *end = get_irg_end(current_ir_graph);
507
508 for (i = get_irn_arity(end) - 1; i >= 0; --i) {
509 ir_node *pred = get_irn_n(end, i);
510
511 if (is_Block(pred))
512 init_tmp_pdom_info(pred, tdi, tdi_list, used, n_blocks);
513 }
514 }
515 }
516
dom_compress(tmp_dom_info * v)517 static void dom_compress(tmp_dom_info *v)
518 {
519 assert (v->ancestor);
520 if (v->ancestor->ancestor) {
521 dom_compress (v->ancestor);
522 if (v->ancestor->label->semi < v->label->semi) {
523 v->label = v->ancestor->label;
524 }
525 v->ancestor = v->ancestor->ancestor;
526 }
527 }
528
529 /**
530 * if V is a root, return v, else return the vertex u, not being the
531 * root, with minimum u->semi on the path from v to its root.
532 */
dom_eval(tmp_dom_info * v)533 inline static tmp_dom_info *dom_eval(tmp_dom_info *v)
534 {
535 if (!v->ancestor) return v;
536 dom_compress (v);
537 return v->label;
538 }
539
540 /** make V W's ancestor */
dom_link(tmp_dom_info * v,tmp_dom_info * w)541 inline static void dom_link(tmp_dom_info *v, tmp_dom_info *w)
542 {
543 w->ancestor = v;
544 }
545
546 /**
547 * Walker: count the number of blocks and clears the dominance info
548 */
count_and_init_blocks_dom(ir_node * bl,void * env)549 static void count_and_init_blocks_dom(ir_node *bl, void *env)
550 {
551 int *n_blocks = (int *) env;
552
553 (*n_blocks) ++;
554
555 memset(get_dom_info(bl), 0, sizeof(ir_dom_info));
556 set_Block_idom(bl, NULL);
557 set_Block_dom_pre_num(bl, -1);
558 set_Block_dom_depth(bl, -1);
559 }
560
compute_doms(ir_graph * irg)561 void compute_doms(ir_graph *irg)
562 {
563 ir_graph *rem = current_ir_graph;
564 int n_blocks, used, i, j;
565 tmp_dom_info *tdi_list; /* Ein Golf? */
566
567 current_ir_graph = irg;
568
569 /* Update graph state */
570 assert(!irg_is_constrained(irg, IR_GRAPH_CONSTRAINT_CONSTRUCTION));
571
572 /* Count the number of blocks in the graph. */
573 n_blocks = 0;
574 irg_block_walk_graph(irg, count_and_init_blocks_dom, NULL, &n_blocks);
575
576 /* Memory for temporary information. */
577 tdi_list = XMALLOCNZ(tmp_dom_info, n_blocks);
578
579 /* We need the out data structure. */
580 assure_irg_outs(irg);
581
582 /* this with a standard walker as passing the parent to the sons isn't
583 simple. */
584 used = 0;
585 inc_irg_block_visited(irg);
586 init_tmp_dom_info(get_irg_start_block(irg), NULL, tdi_list, &used, n_blocks);
587 /* If not all blocks are reachable from Start by out edges this assertion
588 fails.
589 assert(used == n_blocks && "Precondition for dom construction violated"); */
590 assert(used <= n_blocks && "Precondition for dom construction violated");
591 n_blocks = used;
592
593
594 for (i = n_blocks-1; i > 0; i--) { /* Don't iterate the root, it's done. */
595 tmp_dom_info *w = &tdi_list[i];
596 ir_node *block = w->block;
597 tmp_dom_info *v;
598 int irn_arity;
599
600 /* Step 2 */
601 irn_arity = get_irn_arity(block);
602 for (j = 0; j < irn_arity; j++) {
603 ir_node *pred = get_Block_cfgpred(block, j);
604 ir_node *pred_block = get_nodes_block(pred);
605 tmp_dom_info *u;
606
607 if (is_Bad(pred) || (get_Block_dom_pre_num (pred_block) == -1))
608 continue; /* unreachable */
609
610 u = dom_eval (&tdi_list[get_Block_dom_pre_num(pred_block)]);
611 if (u->semi < w->semi)
612 w->semi = u->semi;
613 }
614
615 /* handle keep-alives if we are at the end block */
616 if (block == get_irg_end_block(irg)) {
617 ir_node *end = get_irg_end(irg);
618
619 irn_arity = get_irn_arity(end);
620 for (j = 0; j < irn_arity; j++) {
621 ir_node *pred = get_irn_n(end, j);
622 tmp_dom_info *u;
623
624 if (!is_Block(pred) || get_Block_dom_pre_num(pred) == -1)
625 continue; /* unreachable */
626
627 u = dom_eval (&tdi_list[get_Block_dom_pre_num(pred)]);
628 if (u->semi < w->semi)
629 w->semi = u->semi;
630 }
631 }
632
633 /* Add w to w->semi's bucket. w is in exactly one bucket, so
634 buckets can been implemented as linked lists. */
635 w->bucket = w->semi->bucket;
636 w->semi->bucket = w;
637
638 dom_link (w->parent, w);
639
640 /* Step 3 */
641 while (w->parent->bucket) {
642 tmp_dom_info *u;
643 v = w->parent->bucket;
644 /* remove v from w->parent->bucket */
645 w->parent->bucket = v->bucket;
646 v->bucket = NULL;
647
648 u = dom_eval (v);
649 if (u->semi < v->semi)
650 v->dom = u;
651 else
652 v->dom = w->parent;
653 }
654 }
655 /* Step 4 */
656 tdi_list[0].dom = NULL;
657 set_Block_idom(tdi_list[0].block, NULL);
658 set_Block_dom_depth(tdi_list[0].block, 1);
659 for (i = 1; i < n_blocks; i++) {
660 tmp_dom_info *w = &tdi_list[i];
661 int depth;
662
663 if (! w->dom)
664 continue; /* control dead */
665
666 if (w->dom != w->semi)
667 w->dom = w->dom->dom;
668 set_Block_idom(w->block, w->dom->block);
669
670 /* blocks dominated by dead one's are still dead */
671 depth = get_Block_dom_depth(w->dom->block);
672 if (depth > 0)
673 ++depth;
674 set_Block_dom_depth(w->block, depth);
675 }
676
677 /* clean up */
678 free(tdi_list);
679
680 /* Do a walk over the tree and assign the tree pre orders. */
681 {
682 unsigned tree_pre_order = 0;
683 dom_tree_walk(get_irg_start_block(irg), assign_tree_dom_pre_order,
684 assign_tree_dom_pre_order_max, &tree_pre_order);
685 }
686 current_ir_graph = rem;
687 add_irg_properties(irg, IR_GRAPH_PROPERTY_CONSISTENT_DOMINANCE);
688 }
689
assure_doms(ir_graph * irg)690 void assure_doms(ir_graph *irg)
691 {
692 if (! irg_has_properties(irg, IR_GRAPH_PROPERTY_CONSISTENT_DOMINANCE))
693 compute_doms(irg);
694 }
695
free_dom(ir_graph * irg)696 void free_dom(ir_graph *irg)
697 {
698 /* Update graph state */
699 clear_irg_properties(irg, IR_GRAPH_PROPERTY_CONSISTENT_DOMINANCE);
700
701 /* With the implementation right now there is nothing to free */
702
703 /* free dominance frontiers */
704 ir_free_dominance_frontiers(irg);
705 }
706
compute_postdoms(ir_graph * irg)707 void compute_postdoms(ir_graph *irg)
708 {
709 ir_graph *rem = current_ir_graph;
710 int n_blocks, used, i, j;
711 tmp_dom_info *tdi_list;
712
713 current_ir_graph = irg;
714
715 /* Update graph state */
716 assert(!irg_is_constrained(irg, IR_GRAPH_CONSTRAINT_CONSTRUCTION));
717
718 /* Count the number of blocks in the graph. */
719 n_blocks = 0;
720 irg_block_walk_graph(irg, count_and_init_blocks_pdom, NULL, &n_blocks);
721
722 /* Memory for temporary information. */
723 tdi_list = XMALLOCNZ(tmp_dom_info, n_blocks);
724
725 /* We need the out data structure. */
726 assure_irg_outs(irg);
727
728 /* this with a standard walker as passing the parent to the sons isn't
729 simple. */
730 used = 0;
731 inc_irg_block_visited(irg);
732 init_tmp_pdom_info(get_irg_end_block(irg), NULL, tdi_list, &used, n_blocks);
733 /* If not all blocks are reachable from End by cfg edges this assertion
734 fails.
735 assert(used == n_blocks && "Precondition for dom construction violated"); */
736 n_blocks = used;
737
738
739 for (i = n_blocks-1; i > 0; i--) { /* Don't iterate the root, it's done. */
740 int irn_arity;
741 tmp_dom_info *w = &tdi_list[i];
742 tmp_dom_info *v;
743
744 /* Step 2 */
745 irn_arity = get_Block_n_cfg_outs_ka(w->block);
746 for (j = 0; j < irn_arity; j++) {
747 ir_node *succ = get_Block_cfg_out_ka(w->block, j);
748 tmp_dom_info *u;
749
750 if (get_Block_postdom_pre_num (succ) == -1)
751 continue; /* endless-loop */
752
753 u = dom_eval (&tdi_list[get_Block_postdom_pre_num(succ)]);
754 if (u->semi < w->semi) w->semi = u->semi;
755 }
756 /* Add w to w->semi's bucket. w is in exactly one bucket, so
757 buckets can be implemented as linked lists. */
758 w->bucket = w->semi->bucket;
759 w->semi->bucket = w;
760
761 dom_link (w->parent, w);
762
763 /* Step 3 */
764 while (w->parent->bucket) {
765 tmp_dom_info *u;
766 v = w->parent->bucket;
767 /* remove v from w->parent->bucket */
768 w->parent->bucket = v->bucket;
769 v->bucket = NULL;
770
771 u = dom_eval(v);
772 if (u->semi < v->semi)
773 v->dom = u;
774 else
775 v->dom = w->parent;
776 }
777 }
778 /* Step 4 */
779 tdi_list[0].dom = NULL;
780 set_Block_ipostdom(tdi_list[0].block, NULL);
781 set_Block_postdom_depth(tdi_list[0].block, 1);
782 for (i = 1; i < n_blocks; i++) {
783 tmp_dom_info *w = &tdi_list[i];
784
785 if (w->dom != w->semi) w->dom = w->dom->dom;
786 set_Block_ipostdom(w->block, w->dom->block);
787 set_Block_postdom_depth(w->block, get_Block_postdom_depth(w->dom->block) + 1);
788 }
789
790 /* clean up */
791 free(tdi_list);
792
793 /* Do a walk over the tree and assign the tree pre orders. */
794 {
795 unsigned tree_pre_order = 0;
796 postdom_tree_walk(get_irg_end_block(irg), assign_tree_postdom_pre_order,
797 assign_tree_postdom_pre_order_max, &tree_pre_order);
798 }
799 current_ir_graph = rem;
800 add_irg_properties(irg, IR_GRAPH_PROPERTY_CONSISTENT_POSTDOMINANCE);
801 }
802
assure_postdoms(ir_graph * irg)803 void assure_postdoms(ir_graph *irg)
804 {
805 if (! irg_has_properties(irg, IR_GRAPH_PROPERTY_CONSISTENT_POSTDOMINANCE))
806 compute_postdoms(irg);
807 }
808
free_postdom(ir_graph * irg)809 void free_postdom(ir_graph *irg)
810 {
811 /* Update graph state */
812 clear_irg_properties(irg, IR_GRAPH_PROPERTY_CONSISTENT_POSTDOMINANCE);
813 }
814