1 /* ET-trees data structure implementation.
2 Contributed by Pavel Nejedly
3 Copyright (C) 2002, 2003, 2004, 2005, 2007, 2008 Free Software
6 This file is part of the libiberty library.
7 Libiberty is free software; you can redistribute it and/or
8 modify it under the terms of the GNU Library General Public
9 License as published by the Free Software Foundation; either
10 version 3 of the License, or (at your option) any later version.
12 Libiberty is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 Library General Public License for more details.
17 You should have received a copy of the GNU Library General Public
18 License along with libiberty; see the file COPYING3. If not see
19 <http://www.gnu.org/licenses/>.
21 The ET-forest structure is described in:
22 D. D. Sleator and R. E. Tarjan. A data structure for dynamic trees.
23 J. G'omput. System Sci., 26(3):362 381, 1983.
28 #include "coretypes.h"
30 #include "et-forest.h"
31 #include "alloc-pool.h"
33 /* We do not enable this with ENABLE_CHECKING, since it is awfully slow. */
37 #include "basic-block.h"
40 /* The occurrence of a node in the et tree. */
43 struct et_node *of; /* The node. */
45 struct et_occ *parent; /* Parent in the splay-tree. */
46 struct et_occ *prev; /* Left son in the splay-tree. */
47 struct et_occ *next; /* Right son in the splay-tree. */
49 int depth; /* The depth of the node is the sum of depth
50 fields on the path to the root. */
51 int min; /* The minimum value of the depth in the subtree
52 is obtained by adding sum of depth fields
53 on the path to the root. */
54 struct et_occ *min_occ; /* The occurrence in the subtree with the minimal
58 static alloc_pool et_nodes;
59 static alloc_pool et_occurrences;
61 /* Changes depth of OCC to D. */
64 set_depth (struct et_occ *occ, int d)
69 occ->min += d - occ->depth;
73 /* Adds D to the depth of OCC. */
76 set_depth_add (struct et_occ *occ, int d)
85 /* Sets prev field of OCC to P. */
88 set_prev (struct et_occ *occ, struct et_occ *t)
91 gcc_assert (occ != t);
99 /* Sets next field of OCC to P. */
102 set_next (struct et_occ *occ, struct et_occ *t)
105 gcc_assert (occ != t);
113 /* Recompute minimum for occurrence OCC. */
116 et_recomp_min (struct et_occ *occ)
118 struct et_occ *mson = occ->prev;
122 && mson->min > occ->next->min))
125 if (mson && mson->min < 0)
127 occ->min = mson->min + occ->depth;
128 occ->min_occ = mson->min_occ;
132 occ->min = occ->depth;
138 /* Checks whether neighborhood of OCC seems sane. */
141 et_check_occ_sanity (struct et_occ *occ)
146 gcc_assert (occ->parent != occ);
147 gcc_assert (occ->prev != occ);
148 gcc_assert (occ->next != occ);
149 gcc_assert (!occ->next || occ->next != occ->prev);
153 gcc_assert (occ->next != occ->parent);
154 gcc_assert (occ->next->parent == occ);
159 gcc_assert (occ->prev != occ->parent);
160 gcc_assert (occ->prev->parent == occ);
163 gcc_assert (!occ->parent
164 || occ->parent->prev == occ
165 || occ->parent->next == occ);
168 /* Checks whether tree rooted at OCC is sane. */
171 et_check_sanity (struct et_occ *occ)
173 et_check_occ_sanity (occ);
175 et_check_sanity (occ->prev);
177 et_check_sanity (occ->next);
180 /* Checks whether tree containing OCC is sane. */
183 et_check_tree_sanity (struct et_occ *occ)
188 et_check_sanity (occ);
191 /* For recording the paths. */
193 /* An ad-hoc constant; if the function has more blocks, this won't work,
194 but since it is used for debugging only, it does not matter. */
195 #define MAX_NODES 100000
198 static void *datas[MAX_NODES];
199 static int depths[MAX_NODES];
201 /* Records the path represented by OCC, with depth incremented by DEPTH. */
204 record_path_before_1 (struct et_occ *occ, int depth)
213 m = record_path_before_1 (occ->prev, depth);
218 fprintf (stderr, "%d (%d); ", ((basic_block) occ->of->data)->index, depth);
220 gcc_assert (len < MAX_NODES);
223 datas[len] = occ->of;
228 m = record_path_before_1 (occ->next, depth);
233 gcc_assert (mn == occ->min + depth - occ->depth);
238 /* Records the path represented by a tree containing OCC. */
241 record_path_before (struct et_occ *occ)
247 record_path_before_1 (occ, 0);
248 fprintf (stderr, "\n");
251 /* Checks whether the path represented by OCC, with depth incremented by DEPTH,
252 was not changed since the last recording. */
255 check_path_after_1 (struct et_occ *occ, int depth)
264 m = check_path_after_1 (occ->next, depth);
270 gcc_assert (depths[len] == depth && datas[len] == occ->of);
274 m = check_path_after_1 (occ->prev, depth);
279 gcc_assert (mn == occ->min + depth - occ->depth);
284 /* Checks whether the path represented by a tree containing OCC was
285 not changed since the last recording. */
288 check_path_after (struct et_occ *occ)
293 check_path_after_1 (occ, 0);
299 /* Splay the occurrence OCC to the root of the tree. */
302 et_splay (struct et_occ *occ)
304 struct et_occ *f, *gf, *ggf;
305 int occ_depth, f_depth, gf_depth;
308 record_path_before (occ);
309 et_check_tree_sanity (occ);
314 occ_depth = occ->depth;
323 set_depth_add (occ, f_depth);
324 occ->min_occ = f->min_occ;
330 set_prev (f, occ->next);
332 set_depth_add (f->prev, occ_depth);
337 set_next (f, occ->prev);
339 set_depth_add (f->next, occ_depth);
341 set_depth (f, -occ_depth);
346 et_check_tree_sanity (occ);
347 check_path_after (occ);
352 gf_depth = gf->depth;
354 set_depth_add (occ, f_depth + gf_depth);
355 occ->min_occ = gf->min_occ;
365 set_prev (gf, f->next);
366 set_prev (f, occ->next);
370 set_depth (f, -occ_depth);
371 set_depth_add (f->prev, occ_depth);
372 set_depth (gf, -f_depth);
373 set_depth_add (gf->prev, f_depth);
378 set_prev (gf, occ->next);
379 set_next (f, occ->prev);
383 set_depth (f, -occ_depth);
384 set_depth_add (f->next, occ_depth);
385 set_depth (gf, -occ_depth - f_depth);
386 set_depth_add (gf->prev, occ_depth + f_depth);
394 set_next (gf, occ->prev);
395 set_prev (f, occ->next);
399 set_depth (f, -occ_depth);
400 set_depth_add (f->prev, occ_depth);
401 set_depth (gf, -occ_depth - f_depth);
402 set_depth_add (gf->next, occ_depth + f_depth);
407 set_next (gf, f->prev);
408 set_next (f, occ->prev);
412 set_depth (f, -occ_depth);
413 set_depth_add (f->next, occ_depth);
414 set_depth (gf, -f_depth);
415 set_depth_add (gf->next, f_depth);
431 et_check_tree_sanity (occ);
436 et_check_sanity (occ);
437 check_path_after (occ);
441 /* Create a new et tree occurrence of NODE. */
443 static struct et_occ *
444 et_new_occ (struct et_node *node)
449 et_occurrences = create_alloc_pool ("et_occ pool", sizeof (struct et_occ), 300);
450 nw = (struct et_occ *) pool_alloc (et_occurrences);
464 /* Create a new et tree containing DATA. */
467 et_new_tree (void *data)
472 et_nodes = create_alloc_pool ("et_node pool", sizeof (struct et_node), 300);
473 nw = (struct et_node *) pool_alloc (et_nodes);
481 nw->rightmost_occ = et_new_occ (nw);
482 nw->parent_occ = NULL;
487 /* Releases et tree T. */
490 et_free_tree (struct et_node *t)
498 pool_free (et_occurrences, t->rightmost_occ);
499 pool_free (et_nodes, t);
502 /* Releases et tree T without maintaining other nodes. */
505 et_free_tree_force (struct et_node *t)
507 pool_free (et_occurrences, t->rightmost_occ);
509 pool_free (et_occurrences, t->parent_occ);
510 pool_free (et_nodes, t);
513 /* Release the alloc pools, if they are empty. */
518 free_alloc_pool_if_empty (&et_occurrences);
519 free_alloc_pool_if_empty (&et_nodes);
522 /* Sets father of et tree T to FATHER. */
525 et_set_father (struct et_node *t, struct et_node *father)
527 struct et_node *left, *right;
528 struct et_occ *rmost, *left_part, *new_f_occ, *p;
530 /* Update the path represented in the splay tree. */
531 new_f_occ = et_new_occ (father);
533 rmost = father->rightmost_occ;
536 left_part = rmost->prev;
538 p = t->rightmost_occ;
541 set_prev (new_f_occ, left_part);
542 set_next (new_f_occ, p);
546 et_recomp_min (new_f_occ);
548 set_prev (rmost, new_f_occ);
550 if (new_f_occ->min + rmost->depth < rmost->min)
552 rmost->min = new_f_occ->min + rmost->depth;
553 rmost->min_occ = new_f_occ->min_occ;
556 t->parent_occ = new_f_occ;
558 /* Update the tree. */
574 et_check_tree_sanity (rmost);
575 record_path_before (rmost);
579 /* Splits the edge from T to its father. */
582 et_split (struct et_node *t)
584 struct et_node *father = t->father;
585 struct et_occ *r, *l, *rmost, *p_occ;
587 /* Update the path represented by the splay tree. */
588 rmost = t->rightmost_occ;
591 for (r = rmost->next; r->prev; r = r->prev)
595 r->prev->parent = NULL;
596 p_occ = t->parent_occ;
598 t->parent_occ = NULL;
601 p_occ->next->parent = NULL;
611 pool_free (et_occurrences, p_occ);
613 /* Update the tree. */
614 if (father->son == t)
615 father->son = t->right;
616 if (father->son == t)
620 t->left->right = t->right;
621 t->right->left = t->left;
623 t->left = t->right = NULL;
627 et_check_tree_sanity (rmost);
628 record_path_before (rmost);
630 et_check_tree_sanity (r);
631 record_path_before (r);
635 /* Finds the nearest common ancestor of the nodes N1 and N2. */
638 et_nca (struct et_node *n1, struct et_node *n2)
640 struct et_occ *o1 = n1->rightmost_occ, *o2 = n2->rightmost_occ, *om;
641 struct et_occ *l, *r, *ret;
656 if (l == o2 || (l && l->parent != NULL))
681 mn = o2->depth + o1->depth;
685 et_check_tree_sanity (o2);
688 if (ret && ret->min + o1->depth + o2->depth < mn)
689 return ret->min_occ->of;
694 /* Checks whether the node UP is an ancestor of the node DOWN. */
697 et_below (struct et_node *down, struct et_node *up)
699 struct et_occ *u = up->rightmost_occ, *d = down->rightmost_occ;
700 struct et_occ *l, *r;
719 if (l == d || l->parent != NULL)
725 et_check_tree_sanity (u);
732 /* In case O1 and O2 are in two different trees, we must just restore the
734 if (r && r->parent != NULL)
740 et_check_tree_sanity (u);
748 return !d->next || d->next->min + d->depth >= 0;
751 /* Returns the root of the tree that contains NODE. */
754 et_root (struct et_node *node)
756 struct et_occ *occ = node->rightmost_occ, *r;
758 /* The root of the tree corresponds to the rightmost occurrence in the
761 for (r = occ; r->next; r = r->next)