1 /* ET-trees data structure implementation.
2 Contributed by Pavel Nejedly
3 Copyright (C) 2002-2015 Free Software Foundation, Inc.
5 This file is part of the libiberty library.
6 Libiberty is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Library General Public
8 License as published by the Free Software Foundation; either
9 version 3 of the License, or (at your option) any later version.
11 Libiberty is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Library General Public License for more details.
16 You should have received a copy of the GNU Library General Public
17 License along with libiberty; see the file COPYING3. If not see
18 <http://www.gnu.org/licenses/>.
20 The ET-forest structure is described in:
21 D. D. Sleator and R. E. Tarjan. A data structure for dynamic trees.
22 J. G'omput. System Sci., 26(3):362 381, 1983.
27 #include "coretypes.h"
28 #include "alloc-pool.h"
29 #include "et-forest.h"
31 /* We do not enable this with ENABLE_CHECKING, since it is awfully slow. */
40 #include "hard-reg-set.h"
43 #include "basic-block.h"
46 /* The occurrence of a node in the et tree. */
49 struct et_node
*of
; /* The node. */
51 struct et_occ
*parent
; /* Parent in the splay-tree. */
52 struct et_occ
*prev
; /* Left son in the splay-tree. */
53 struct et_occ
*next
; /* Right son in the splay-tree. */
55 int depth
; /* The depth of the node is the sum of depth
56 fields on the path to the root. */
57 int min
; /* The minimum value of the depth in the subtree
58 is obtained by adding sum of depth fields
59 on the path to the root. */
60 struct et_occ
*min_occ
; /* The occurrence in the subtree with the minimal
63 /* Pool allocation new operator. */
64 inline void *operator new (size_t)
66 return pool
.allocate ();
69 /* Delete operator utilizing pool allocation. */
70 inline void operator delete (void *ptr
)
72 pool
.remove ((et_occ
*) ptr
);
75 /* Memory allocation pool. */
76 static pool_allocator
<et_occ
> pool
;
80 pool_allocator
<et_node
> et_node::pool ("et_nodes pool", 300);
81 pool_allocator
<et_occ
> et_occ::pool ("et_occ pool", 300);
83 /* Changes depth of OCC to D. */
86 set_depth (struct et_occ
*occ
, int d
)
91 occ
->min
+= d
- occ
->depth
;
95 /* Adds D to the depth of OCC. */
98 set_depth_add (struct et_occ
*occ
, int d
)
107 /* Sets prev field of OCC to P. */
110 set_prev (struct et_occ
*occ
, struct et_occ
*t
)
113 gcc_assert (occ
!= t
);
121 /* Sets next field of OCC to P. */
124 set_next (struct et_occ
*occ
, struct et_occ
*t
)
127 gcc_assert (occ
!= t
);
135 /* Recompute minimum for occurrence OCC. */
138 et_recomp_min (struct et_occ
*occ
)
140 struct et_occ
*mson
= occ
->prev
;
144 && mson
->min
> occ
->next
->min
))
147 if (mson
&& mson
->min
< 0)
149 occ
->min
= mson
->min
+ occ
->depth
;
150 occ
->min_occ
= mson
->min_occ
;
154 occ
->min
= occ
->depth
;
160 /* Checks whether neighborhood of OCC seems sane. */
163 et_check_occ_sanity (struct et_occ
*occ
)
168 gcc_assert (occ
->parent
!= occ
);
169 gcc_assert (occ
->prev
!= occ
);
170 gcc_assert (occ
->next
!= occ
);
171 gcc_assert (!occ
->next
|| occ
->next
!= occ
->prev
);
175 gcc_assert (occ
->next
!= occ
->parent
);
176 gcc_assert (occ
->next
->parent
== occ
);
181 gcc_assert (occ
->prev
!= occ
->parent
);
182 gcc_assert (occ
->prev
->parent
== occ
);
185 gcc_assert (!occ
->parent
186 || occ
->parent
->prev
== occ
187 || occ
->parent
->next
== occ
);
190 /* Checks whether tree rooted at OCC is sane. */
193 et_check_sanity (struct et_occ
*occ
)
195 et_check_occ_sanity (occ
);
197 et_check_sanity (occ
->prev
);
199 et_check_sanity (occ
->next
);
202 /* Checks whether tree containing OCC is sane. */
205 et_check_tree_sanity (struct et_occ
*occ
)
210 et_check_sanity (occ
);
213 /* For recording the paths. */
215 /* An ad-hoc constant; if the function has more blocks, this won't work,
216 but since it is used for debugging only, it does not matter. */
217 #define MAX_NODES 100000
220 static void *datas
[MAX_NODES
];
221 static int depths
[MAX_NODES
];
223 /* Records the path represented by OCC, with depth incremented by DEPTH. */
226 record_path_before_1 (struct et_occ
*occ
, int depth
)
235 m
= record_path_before_1 (occ
->prev
, depth
);
240 fprintf (stderr
, "%d (%d); ", ((basic_block
) occ
->of
->data
)->index
, depth
);
242 gcc_assert (len
< MAX_NODES
);
245 datas
[len
] = occ
->of
;
250 m
= record_path_before_1 (occ
->next
, depth
);
255 gcc_assert (mn
== occ
->min
+ depth
- occ
->depth
);
260 /* Records the path represented by a tree containing OCC. */
263 record_path_before (struct et_occ
*occ
)
269 record_path_before_1 (occ
, 0);
270 fprintf (stderr
, "\n");
273 /* Checks whether the path represented by OCC, with depth incremented by DEPTH,
274 was not changed since the last recording. */
277 check_path_after_1 (struct et_occ
*occ
, int depth
)
286 m
= check_path_after_1 (occ
->next
, depth
);
292 gcc_assert (depths
[len
] == depth
&& datas
[len
] == occ
->of
);
296 m
= check_path_after_1 (occ
->prev
, depth
);
301 gcc_assert (mn
== occ
->min
+ depth
- occ
->depth
);
306 /* Checks whether the path represented by a tree containing OCC was
307 not changed since the last recording. */
310 check_path_after (struct et_occ
*occ
)
315 check_path_after_1 (occ
, 0);
321 /* Splay the occurrence OCC to the root of the tree. */
324 et_splay (struct et_occ
*occ
)
326 struct et_occ
*f
, *gf
, *ggf
;
327 int occ_depth
, f_depth
, gf_depth
;
330 record_path_before (occ
);
331 et_check_tree_sanity (occ
);
336 occ_depth
= occ
->depth
;
345 set_depth_add (occ
, f_depth
);
346 occ
->min_occ
= f
->min_occ
;
352 set_prev (f
, occ
->next
);
354 set_depth_add (f
->prev
, occ_depth
);
359 set_next (f
, occ
->prev
);
361 set_depth_add (f
->next
, occ_depth
);
363 set_depth (f
, -occ_depth
);
368 et_check_tree_sanity (occ
);
369 check_path_after (occ
);
374 gf_depth
= gf
->depth
;
376 set_depth_add (occ
, f_depth
+ gf_depth
);
377 occ
->min_occ
= gf
->min_occ
;
387 set_prev (gf
, f
->next
);
388 set_prev (f
, occ
->next
);
392 set_depth (f
, -occ_depth
);
393 set_depth_add (f
->prev
, occ_depth
);
394 set_depth (gf
, -f_depth
);
395 set_depth_add (gf
->prev
, f_depth
);
400 set_prev (gf
, occ
->next
);
401 set_next (f
, occ
->prev
);
405 set_depth (f
, -occ_depth
);
406 set_depth_add (f
->next
, occ_depth
);
407 set_depth (gf
, -occ_depth
- f_depth
);
408 set_depth_add (gf
->prev
, occ_depth
+ f_depth
);
416 set_next (gf
, occ
->prev
);
417 set_prev (f
, occ
->next
);
421 set_depth (f
, -occ_depth
);
422 set_depth_add (f
->prev
, occ_depth
);
423 set_depth (gf
, -occ_depth
- f_depth
);
424 set_depth_add (gf
->next
, occ_depth
+ f_depth
);
429 set_next (gf
, f
->prev
);
430 set_next (f
, occ
->prev
);
434 set_depth (f
, -occ_depth
);
435 set_depth_add (f
->next
, occ_depth
);
436 set_depth (gf
, -f_depth
);
437 set_depth_add (gf
->next
, f_depth
);
453 et_check_tree_sanity (occ
);
458 et_check_sanity (occ
);
459 check_path_after (occ
);
463 /* Create a new et tree occurrence of NODE. */
465 static struct et_occ
*
466 et_new_occ (struct et_node
*node
)
468 et_occ
*nw
= new et_occ
;
482 /* Create a new et tree containing DATA. */
485 et_new_tree (void *data
)
497 nw
->rightmost_occ
= et_new_occ (nw
);
498 nw
->parent_occ
= NULL
;
503 /* Releases et tree T. */
506 et_free_tree (struct et_node
*t
)
514 delete t
->rightmost_occ
;
518 /* Releases et tree T without maintaining other nodes. */
521 et_free_tree_force (struct et_node
*t
)
523 delete t
->rightmost_occ
;
525 delete t
->parent_occ
;
529 /* Release the alloc pools, if they are empty. */
534 et_occ::pool
.release_if_empty ();
535 et_node::pool
.release_if_empty ();
538 /* Sets father of et tree T to FATHER. */
541 et_set_father (struct et_node
*t
, struct et_node
*father
)
543 struct et_node
*left
, *right
;
544 struct et_occ
*rmost
, *left_part
, *new_f_occ
, *p
;
546 /* Update the path represented in the splay tree. */
547 new_f_occ
= et_new_occ (father
);
549 rmost
= father
->rightmost_occ
;
552 left_part
= rmost
->prev
;
554 p
= t
->rightmost_occ
;
557 set_prev (new_f_occ
, left_part
);
558 set_next (new_f_occ
, p
);
562 et_recomp_min (new_f_occ
);
564 set_prev (rmost
, new_f_occ
);
566 if (new_f_occ
->min
+ rmost
->depth
< rmost
->min
)
568 rmost
->min
= new_f_occ
->min
+ rmost
->depth
;
569 rmost
->min_occ
= new_f_occ
->min_occ
;
572 t
->parent_occ
= new_f_occ
;
574 /* Update the tree. */
590 et_check_tree_sanity (rmost
);
591 record_path_before (rmost
);
595 /* Splits the edge from T to its father. */
598 et_split (struct et_node
*t
)
600 struct et_node
*father
= t
->father
;
601 struct et_occ
*r
, *l
, *rmost
, *p_occ
;
603 /* Update the path represented by the splay tree. */
604 rmost
= t
->rightmost_occ
;
607 for (r
= rmost
->next
; r
->prev
; r
= r
->prev
)
611 r
->prev
->parent
= NULL
;
612 p_occ
= t
->parent_occ
;
614 t
->parent_occ
= NULL
;
617 p_occ
->next
->parent
= NULL
;
629 /* Update the tree. */
630 if (father
->son
== t
)
631 father
->son
= t
->right
;
632 if (father
->son
== t
)
636 t
->left
->right
= t
->right
;
637 t
->right
->left
= t
->left
;
639 t
->left
= t
->right
= NULL
;
643 et_check_tree_sanity (rmost
);
644 record_path_before (rmost
);
646 et_check_tree_sanity (r
);
647 record_path_before (r
);
651 /* Finds the nearest common ancestor of the nodes N1 and N2. */
654 et_nca (struct et_node
*n1
, struct et_node
*n2
)
656 struct et_occ
*o1
= n1
->rightmost_occ
, *o2
= n2
->rightmost_occ
, *om
;
657 struct et_occ
*l
, *r
, *ret
;
672 if (l
== o2
|| (l
&& l
->parent
!= NULL
))
680 else if (r
== o2
|| (r
&& r
->parent
!= NULL
))
690 /* O1 and O2 are in different components of the forest. */
706 mn
= o2
->depth
+ o1
->depth
;
710 et_check_tree_sanity (o2
);
713 if (ret
&& ret
->min
+ o1
->depth
+ o2
->depth
< mn
)
714 return ret
->min_occ
->of
;
719 /* Checks whether the node UP is an ancestor of the node DOWN. */
722 et_below (struct et_node
*down
, struct et_node
*up
)
724 struct et_occ
*u
= up
->rightmost_occ
, *d
= down
->rightmost_occ
;
725 struct et_occ
*l
, *r
;
744 if (l
== d
|| l
->parent
!= NULL
)
750 et_check_tree_sanity (u
);
757 /* In case O1 and O2 are in two different trees, we must just restore the
759 if (r
&& r
->parent
!= NULL
)
765 et_check_tree_sanity (u
);
773 return !d
->next
|| d
->next
->min
+ d
->depth
>= 0;
776 /* Returns the root of the tree that contains NODE. */
779 et_root (struct et_node
*node
)
781 struct et_occ
*occ
= node
->rightmost_occ
, *r
;
783 /* The root of the tree corresponds to the rightmost occurrence in the
786 for (r
= occ
; r
->next
; r
= r
->next
)