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f8032688 | 1 | /* Calculate (post)dominators in slightly super-linear time. |
c8d3e15a | 2 | Copyright (C) 2000, 2003, 2004, 2005 Free Software Foundation, Inc. |
f8032688 | 3 | Contributed by Michael Matz (matz@ifh.de). |
3a538a66 | 4 | |
1322177d | 5 | This file is part of GCC. |
3a538a66 | 6 | |
1322177d LB |
7 | GCC is free software; you can redistribute it and/or modify it |
8 | under the terms of the GNU General Public License as published by | |
f8032688 MM |
9 | the Free Software Foundation; either version 2, or (at your option) |
10 | any later version. | |
11 | ||
1322177d LB |
12 | GCC is distributed in the hope that it will be useful, but WITHOUT |
13 | ANY WARRANTY; without even the implied warranty of MERCHANTABILITY | |
14 | or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public | |
15 | License for more details. | |
f8032688 MM |
16 | |
17 | You should have received a copy of the GNU General Public License | |
1322177d | 18 | along with GCC; see the file COPYING. If not, write to the Free |
366ccddb KC |
19 | Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA |
20 | 02110-1301, USA. */ | |
f8032688 MM |
21 | |
22 | /* This file implements the well known algorithm from Lengauer and Tarjan | |
23 | to compute the dominators in a control flow graph. A basic block D is said | |
24 | to dominate another block X, when all paths from the entry node of the CFG | |
25 | to X go also over D. The dominance relation is a transitive reflexive | |
26 | relation and its minimal transitive reduction is a tree, called the | |
27 | dominator tree. So for each block X besides the entry block exists a | |
28 | block I(X), called the immediate dominator of X, which is the parent of X | |
29 | in the dominator tree. | |
30 | ||
a1f300c0 | 31 | The algorithm computes this dominator tree implicitly by computing for |
f8032688 | 32 | each block its immediate dominator. We use tree balancing and path |
f3b569ca | 33 | compression, so it's the O(e*a(e,v)) variant, where a(e,v) is the very |
f8032688 MM |
34 | slowly growing functional inverse of the Ackerman function. */ |
35 | ||
36 | #include "config.h" | |
37 | #include "system.h" | |
4977bab6 ZW |
38 | #include "coretypes.h" |
39 | #include "tm.h" | |
f8032688 MM |
40 | #include "rtl.h" |
41 | #include "hard-reg-set.h" | |
7932a3db | 42 | #include "obstack.h" |
f8032688 | 43 | #include "basic-block.h" |
4c714dd4 | 44 | #include "toplev.h" |
355be0dc | 45 | #include "et-forest.h" |
74c96e0c | 46 | #include "timevar.h" |
f8032688 | 47 | |
d47cc544 SB |
48 | /* Whether the dominators and the postdominators are available. */ |
49 | enum dom_state dom_computed[2]; | |
f8032688 MM |
50 | |
51 | /* We name our nodes with integers, beginning with 1. Zero is reserved for | |
52 | 'undefined' or 'end of list'. The name of each node is given by the dfs | |
53 | number of the corresponding basic block. Please note, that we include the | |
54 | artificial ENTRY_BLOCK (or EXIT_BLOCK in the post-dom case) in our lists to | |
24bd1a0b | 55 | support multiple entry points. Its dfs number is of course 1. */ |
f8032688 MM |
56 | |
57 | /* Type of Basic Block aka. TBB */ | |
58 | typedef unsigned int TBB; | |
59 | ||
60 | /* We work in a poor-mans object oriented fashion, and carry an instance of | |
61 | this structure through all our 'methods'. It holds various arrays | |
62 | reflecting the (sub)structure of the flowgraph. Most of them are of type | |
63 | TBB and are also indexed by TBB. */ | |
64 | ||
65 | struct dom_info | |
66 | { | |
67 | /* The parent of a node in the DFS tree. */ | |
68 | TBB *dfs_parent; | |
69 | /* For a node x key[x] is roughly the node nearest to the root from which | |
70 | exists a way to x only over nodes behind x. Such a node is also called | |
71 | semidominator. */ | |
72 | TBB *key; | |
73 | /* The value in path_min[x] is the node y on the path from x to the root of | |
74 | the tree x is in with the smallest key[y]. */ | |
75 | TBB *path_min; | |
76 | /* bucket[x] points to the first node of the set of nodes having x as key. */ | |
77 | TBB *bucket; | |
78 | /* And next_bucket[x] points to the next node. */ | |
79 | TBB *next_bucket; | |
80 | /* After the algorithm is done, dom[x] contains the immediate dominator | |
81 | of x. */ | |
82 | TBB *dom; | |
83 | ||
84 | /* The following few fields implement the structures needed for disjoint | |
85 | sets. */ | |
86 | /* set_chain[x] is the next node on the path from x to the representant | |
87 | of the set containing x. If set_chain[x]==0 then x is a root. */ | |
88 | TBB *set_chain; | |
89 | /* set_size[x] is the number of elements in the set named by x. */ | |
90 | unsigned int *set_size; | |
91 | /* set_child[x] is used for balancing the tree representing a set. It can | |
92 | be understood as the next sibling of x. */ | |
93 | TBB *set_child; | |
94 | ||
95 | /* If b is the number of a basic block (BB->index), dfs_order[b] is the | |
96 | number of that node in DFS order counted from 1. This is an index | |
97 | into most of the other arrays in this structure. */ | |
98 | TBB *dfs_order; | |
09da1532 | 99 | /* If x is the DFS-index of a node which corresponds with a basic block, |
f8032688 MM |
100 | dfs_to_bb[x] is that basic block. Note, that in our structure there are |
101 | more nodes that basic blocks, so only dfs_to_bb[dfs_order[bb->index]]==bb | |
102 | is true for every basic block bb, but not the opposite. */ | |
103 | basic_block *dfs_to_bb; | |
104 | ||
26e0e410 | 105 | /* This is the next free DFS number when creating the DFS tree. */ |
f8032688 MM |
106 | unsigned int dfsnum; |
107 | /* The number of nodes in the DFS tree (==dfsnum-1). */ | |
108 | unsigned int nodes; | |
26e0e410 RH |
109 | |
110 | /* Blocks with bits set here have a fake edge to EXIT. These are used | |
111 | to turn a DFS forest into a proper tree. */ | |
112 | bitmap fake_exit_edge; | |
f8032688 MM |
113 | }; |
114 | ||
26e0e410 | 115 | static void init_dom_info (struct dom_info *, enum cdi_direction); |
7080f735 AJ |
116 | static void free_dom_info (struct dom_info *); |
117 | static void calc_dfs_tree_nonrec (struct dom_info *, basic_block, | |
118 | enum cdi_direction); | |
119 | static void calc_dfs_tree (struct dom_info *, enum cdi_direction); | |
120 | static void compress (struct dom_info *, TBB); | |
121 | static TBB eval (struct dom_info *, TBB); | |
122 | static void link_roots (struct dom_info *, TBB, TBB); | |
123 | static void calc_idoms (struct dom_info *, enum cdi_direction); | |
d47cc544 | 124 | void debug_dominance_info (enum cdi_direction); |
f8032688 | 125 | |
6de9cd9a DN |
126 | /* Keeps track of the*/ |
127 | static unsigned n_bbs_in_dom_tree[2]; | |
128 | ||
f8032688 MM |
129 | /* Helper macro for allocating and initializing an array, |
130 | for aesthetic reasons. */ | |
131 | #define init_ar(var, type, num, content) \ | |
3a538a66 KH |
132 | do \ |
133 | { \ | |
134 | unsigned int i = 1; /* Catch content == i. */ \ | |
135 | if (! (content)) \ | |
5ed6ace5 | 136 | (var) = XCNEWVEC (type, num); \ |
3a538a66 KH |
137 | else \ |
138 | { \ | |
5ed6ace5 | 139 | (var) = XNEWVEC (type, (num)); \ |
3a538a66 KH |
140 | for (i = 0; i < num; i++) \ |
141 | (var)[i] = (content); \ | |
142 | } \ | |
143 | } \ | |
144 | while (0) | |
f8032688 MM |
145 | |
146 | /* Allocate all needed memory in a pessimistic fashion (so we round up). | |
4912a07c | 147 | This initializes the contents of DI, which already must be allocated. */ |
f8032688 MM |
148 | |
149 | static void | |
26e0e410 | 150 | init_dom_info (struct dom_info *di, enum cdi_direction dir) |
f8032688 | 151 | { |
24bd1a0b | 152 | unsigned int num = n_basic_blocks; |
f8032688 MM |
153 | init_ar (di->dfs_parent, TBB, num, 0); |
154 | init_ar (di->path_min, TBB, num, i); | |
155 | init_ar (di->key, TBB, num, i); | |
156 | init_ar (di->dom, TBB, num, 0); | |
157 | ||
158 | init_ar (di->bucket, TBB, num, 0); | |
159 | init_ar (di->next_bucket, TBB, num, 0); | |
160 | ||
161 | init_ar (di->set_chain, TBB, num, 0); | |
162 | init_ar (di->set_size, unsigned int, num, 1); | |
163 | init_ar (di->set_child, TBB, num, 0); | |
164 | ||
d55bc081 | 165 | init_ar (di->dfs_order, TBB, (unsigned int) last_basic_block + 1, 0); |
f8032688 MM |
166 | init_ar (di->dfs_to_bb, basic_block, num, 0); |
167 | ||
168 | di->dfsnum = 1; | |
169 | di->nodes = 0; | |
26e0e410 | 170 | |
8bdbfff5 | 171 | di->fake_exit_edge = dir ? BITMAP_ALLOC (NULL) : NULL; |
f8032688 MM |
172 | } |
173 | ||
174 | #undef init_ar | |
175 | ||
176 | /* Free all allocated memory in DI, but not DI itself. */ | |
177 | ||
178 | static void | |
7080f735 | 179 | free_dom_info (struct dom_info *di) |
f8032688 MM |
180 | { |
181 | free (di->dfs_parent); | |
182 | free (di->path_min); | |
183 | free (di->key); | |
184 | free (di->dom); | |
185 | free (di->bucket); | |
186 | free (di->next_bucket); | |
187 | free (di->set_chain); | |
188 | free (di->set_size); | |
189 | free (di->set_child); | |
190 | free (di->dfs_order); | |
191 | free (di->dfs_to_bb); | |
8bdbfff5 | 192 | BITMAP_FREE (di->fake_exit_edge); |
f8032688 MM |
193 | } |
194 | ||
195 | /* The nonrecursive variant of creating a DFS tree. DI is our working | |
196 | structure, BB the starting basic block for this tree and REVERSE | |
197 | is true, if predecessors should be visited instead of successors of a | |
198 | node. After this is done all nodes reachable from BB were visited, have | |
199 | assigned their dfs number and are linked together to form a tree. */ | |
200 | ||
201 | static void | |
26e0e410 RH |
202 | calc_dfs_tree_nonrec (struct dom_info *di, basic_block bb, |
203 | enum cdi_direction reverse) | |
f8032688 | 204 | { |
f8032688 MM |
205 | /* We call this _only_ if bb is not already visited. */ |
206 | edge e; | |
207 | TBB child_i, my_i = 0; | |
628f6a4e BE |
208 | edge_iterator *stack; |
209 | edge_iterator ei, einext; | |
f8032688 MM |
210 | int sp; |
211 | /* Start block (ENTRY_BLOCK_PTR for forward problem, EXIT_BLOCK for backward | |
212 | problem). */ | |
213 | basic_block en_block; | |
214 | /* Ending block. */ | |
215 | basic_block ex_block; | |
216 | ||
5ed6ace5 | 217 | stack = XNEWVEC (edge_iterator, n_basic_blocks + 1); |
f8032688 MM |
218 | sp = 0; |
219 | ||
220 | /* Initialize our border blocks, and the first edge. */ | |
221 | if (reverse) | |
222 | { | |
628f6a4e | 223 | ei = ei_start (bb->preds); |
f8032688 MM |
224 | en_block = EXIT_BLOCK_PTR; |
225 | ex_block = ENTRY_BLOCK_PTR; | |
226 | } | |
227 | else | |
228 | { | |
628f6a4e | 229 | ei = ei_start (bb->succs); |
f8032688 MM |
230 | en_block = ENTRY_BLOCK_PTR; |
231 | ex_block = EXIT_BLOCK_PTR; | |
232 | } | |
233 | ||
234 | /* When the stack is empty we break out of this loop. */ | |
235 | while (1) | |
236 | { | |
237 | basic_block bn; | |
238 | ||
239 | /* This loop traverses edges e in depth first manner, and fills the | |
240 | stack. */ | |
628f6a4e | 241 | while (!ei_end_p (ei)) |
f8032688 | 242 | { |
628f6a4e | 243 | e = ei_edge (ei); |
f8032688 MM |
244 | |
245 | /* Deduce from E the current and the next block (BB and BN), and the | |
246 | next edge. */ | |
247 | if (reverse) | |
248 | { | |
249 | bn = e->src; | |
250 | ||
251 | /* If the next node BN is either already visited or a border | |
252 | block the current edge is useless, and simply overwritten | |
253 | with the next edge out of the current node. */ | |
0b17ab2f | 254 | if (bn == ex_block || di->dfs_order[bn->index]) |
f8032688 | 255 | { |
628f6a4e | 256 | ei_next (&ei); |
f8032688 MM |
257 | continue; |
258 | } | |
259 | bb = e->dest; | |
628f6a4e | 260 | einext = ei_start (bn->preds); |
f8032688 MM |
261 | } |
262 | else | |
263 | { | |
264 | bn = e->dest; | |
0b17ab2f | 265 | if (bn == ex_block || di->dfs_order[bn->index]) |
f8032688 | 266 | { |
628f6a4e | 267 | ei_next (&ei); |
f8032688 MM |
268 | continue; |
269 | } | |
270 | bb = e->src; | |
628f6a4e | 271 | einext = ei_start (bn->succs); |
f8032688 MM |
272 | } |
273 | ||
ced3f397 | 274 | gcc_assert (bn != en_block); |
f8032688 MM |
275 | |
276 | /* Fill the DFS tree info calculatable _before_ recursing. */ | |
277 | if (bb != en_block) | |
0b17ab2f | 278 | my_i = di->dfs_order[bb->index]; |
f8032688 | 279 | else |
d55bc081 | 280 | my_i = di->dfs_order[last_basic_block]; |
0b17ab2f | 281 | child_i = di->dfs_order[bn->index] = di->dfsnum++; |
f8032688 MM |
282 | di->dfs_to_bb[child_i] = bn; |
283 | di->dfs_parent[child_i] = my_i; | |
284 | ||
285 | /* Save the current point in the CFG on the stack, and recurse. */ | |
628f6a4e BE |
286 | stack[sp++] = ei; |
287 | ei = einext; | |
f8032688 MM |
288 | } |
289 | ||
290 | if (!sp) | |
291 | break; | |
628f6a4e | 292 | ei = stack[--sp]; |
f8032688 MM |
293 | |
294 | /* OK. The edge-list was exhausted, meaning normally we would | |
295 | end the recursion. After returning from the recursive call, | |
296 | there were (may be) other statements which were run after a | |
297 | child node was completely considered by DFS. Here is the | |
298 | point to do it in the non-recursive variant. | |
299 | E.g. The block just completed is in e->dest for forward DFS, | |
300 | the block not yet completed (the parent of the one above) | |
301 | in e->src. This could be used e.g. for computing the number of | |
302 | descendants or the tree depth. */ | |
628f6a4e | 303 | ei_next (&ei); |
f8032688 MM |
304 | } |
305 | free (stack); | |
306 | } | |
307 | ||
308 | /* The main entry for calculating the DFS tree or forest. DI is our working | |
309 | structure and REVERSE is true, if we are interested in the reverse flow | |
310 | graph. In that case the result is not necessarily a tree but a forest, | |
311 | because there may be nodes from which the EXIT_BLOCK is unreachable. */ | |
312 | ||
313 | static void | |
7080f735 | 314 | calc_dfs_tree (struct dom_info *di, enum cdi_direction reverse) |
f8032688 MM |
315 | { |
316 | /* The first block is the ENTRY_BLOCK (or EXIT_BLOCK if REVERSE). */ | |
317 | basic_block begin = reverse ? EXIT_BLOCK_PTR : ENTRY_BLOCK_PTR; | |
d55bc081 | 318 | di->dfs_order[last_basic_block] = di->dfsnum; |
f8032688 MM |
319 | di->dfs_to_bb[di->dfsnum] = begin; |
320 | di->dfsnum++; | |
321 | ||
322 | calc_dfs_tree_nonrec (di, begin, reverse); | |
323 | ||
324 | if (reverse) | |
325 | { | |
326 | /* In the post-dom case we may have nodes without a path to EXIT_BLOCK. | |
327 | They are reverse-unreachable. In the dom-case we disallow such | |
26e0e410 RH |
328 | nodes, but in post-dom we have to deal with them. |
329 | ||
330 | There are two situations in which this occurs. First, noreturn | |
331 | functions. Second, infinite loops. In the first case we need to | |
332 | pretend that there is an edge to the exit block. In the second | |
333 | case, we wind up with a forest. We need to process all noreturn | |
334 | blocks before we know if we've got any infinite loops. */ | |
335 | ||
e0082a72 | 336 | basic_block b; |
26e0e410 RH |
337 | bool saw_unconnected = false; |
338 | ||
e0082a72 | 339 | FOR_EACH_BB_REVERSE (b) |
f8032688 | 340 | { |
628f6a4e | 341 | if (EDGE_COUNT (b->succs) > 0) |
26e0e410 RH |
342 | { |
343 | if (di->dfs_order[b->index] == 0) | |
344 | saw_unconnected = true; | |
345 | continue; | |
346 | } | |
347 | bitmap_set_bit (di->fake_exit_edge, b->index); | |
0b17ab2f | 348 | di->dfs_order[b->index] = di->dfsnum; |
f8032688 | 349 | di->dfs_to_bb[di->dfsnum] = b; |
26e0e410 | 350 | di->dfs_parent[di->dfsnum] = di->dfs_order[last_basic_block]; |
f8032688 MM |
351 | di->dfsnum++; |
352 | calc_dfs_tree_nonrec (di, b, reverse); | |
353 | } | |
26e0e410 RH |
354 | |
355 | if (saw_unconnected) | |
356 | { | |
357 | FOR_EACH_BB_REVERSE (b) | |
358 | { | |
359 | if (di->dfs_order[b->index]) | |
360 | continue; | |
361 | bitmap_set_bit (di->fake_exit_edge, b->index); | |
362 | di->dfs_order[b->index] = di->dfsnum; | |
363 | di->dfs_to_bb[di->dfsnum] = b; | |
364 | di->dfs_parent[di->dfsnum] = di->dfs_order[last_basic_block]; | |
365 | di->dfsnum++; | |
366 | calc_dfs_tree_nonrec (di, b, reverse); | |
367 | } | |
368 | } | |
f8032688 MM |
369 | } |
370 | ||
371 | di->nodes = di->dfsnum - 1; | |
372 | ||
24bd1a0b DB |
373 | /* This aborts e.g. when there is _no_ path from ENTRY to EXIT at all. */ |
374 | gcc_assert (di->nodes == (unsigned int) n_basic_blocks - 1); | |
f8032688 MM |
375 | } |
376 | ||
377 | /* Compress the path from V to the root of its set and update path_min at the | |
378 | same time. After compress(di, V) set_chain[V] is the root of the set V is | |
379 | in and path_min[V] is the node with the smallest key[] value on the path | |
380 | from V to that root. */ | |
381 | ||
382 | static void | |
7080f735 | 383 | compress (struct dom_info *di, TBB v) |
f8032688 MM |
384 | { |
385 | /* Btw. It's not worth to unrecurse compress() as the depth is usually not | |
386 | greater than 5 even for huge graphs (I've not seen call depth > 4). | |
387 | Also performance wise compress() ranges _far_ behind eval(). */ | |
388 | TBB parent = di->set_chain[v]; | |
389 | if (di->set_chain[parent]) | |
390 | { | |
391 | compress (di, parent); | |
392 | if (di->key[di->path_min[parent]] < di->key[di->path_min[v]]) | |
393 | di->path_min[v] = di->path_min[parent]; | |
394 | di->set_chain[v] = di->set_chain[parent]; | |
395 | } | |
396 | } | |
397 | ||
398 | /* Compress the path from V to the set root of V if needed (when the root has | |
399 | changed since the last call). Returns the node with the smallest key[] | |
400 | value on the path from V to the root. */ | |
401 | ||
402 | static inline TBB | |
7080f735 | 403 | eval (struct dom_info *di, TBB v) |
f8032688 MM |
404 | { |
405 | /* The representant of the set V is in, also called root (as the set | |
406 | representation is a tree). */ | |
407 | TBB rep = di->set_chain[v]; | |
408 | ||
409 | /* V itself is the root. */ | |
410 | if (!rep) | |
411 | return di->path_min[v]; | |
412 | ||
413 | /* Compress only if necessary. */ | |
414 | if (di->set_chain[rep]) | |
415 | { | |
416 | compress (di, v); | |
417 | rep = di->set_chain[v]; | |
418 | } | |
419 | ||
420 | if (di->key[di->path_min[rep]] >= di->key[di->path_min[v]]) | |
421 | return di->path_min[v]; | |
422 | else | |
423 | return di->path_min[rep]; | |
424 | } | |
425 | ||
426 | /* This essentially merges the two sets of V and W, giving a single set with | |
427 | the new root V. The internal representation of these disjoint sets is a | |
428 | balanced tree. Currently link(V,W) is only used with V being the parent | |
429 | of W. */ | |
430 | ||
431 | static void | |
7080f735 | 432 | link_roots (struct dom_info *di, TBB v, TBB w) |
f8032688 MM |
433 | { |
434 | TBB s = w; | |
435 | ||
436 | /* Rebalance the tree. */ | |
437 | while (di->key[di->path_min[w]] < di->key[di->path_min[di->set_child[s]]]) | |
438 | { | |
439 | if (di->set_size[s] + di->set_size[di->set_child[di->set_child[s]]] | |
440 | >= 2 * di->set_size[di->set_child[s]]) | |
441 | { | |
442 | di->set_chain[di->set_child[s]] = s; | |
443 | di->set_child[s] = di->set_child[di->set_child[s]]; | |
444 | } | |
445 | else | |
446 | { | |
447 | di->set_size[di->set_child[s]] = di->set_size[s]; | |
448 | s = di->set_chain[s] = di->set_child[s]; | |
449 | } | |
450 | } | |
451 | ||
452 | di->path_min[s] = di->path_min[w]; | |
453 | di->set_size[v] += di->set_size[w]; | |
454 | if (di->set_size[v] < 2 * di->set_size[w]) | |
455 | { | |
456 | TBB tmp = s; | |
457 | s = di->set_child[v]; | |
458 | di->set_child[v] = tmp; | |
459 | } | |
460 | ||
461 | /* Merge all subtrees. */ | |
462 | while (s) | |
463 | { | |
464 | di->set_chain[s] = v; | |
465 | s = di->set_child[s]; | |
466 | } | |
467 | } | |
468 | ||
469 | /* This calculates the immediate dominators (or post-dominators if REVERSE is | |
470 | true). DI is our working structure and should hold the DFS forest. | |
471 | On return the immediate dominator to node V is in di->dom[V]. */ | |
472 | ||
473 | static void | |
7080f735 | 474 | calc_idoms (struct dom_info *di, enum cdi_direction reverse) |
f8032688 MM |
475 | { |
476 | TBB v, w, k, par; | |
477 | basic_block en_block; | |
628f6a4e BE |
478 | edge_iterator ei, einext; |
479 | ||
f8032688 MM |
480 | if (reverse) |
481 | en_block = EXIT_BLOCK_PTR; | |
482 | else | |
483 | en_block = ENTRY_BLOCK_PTR; | |
484 | ||
485 | /* Go backwards in DFS order, to first look at the leafs. */ | |
486 | v = di->nodes; | |
487 | while (v > 1) | |
488 | { | |
489 | basic_block bb = di->dfs_to_bb[v]; | |
628f6a4e | 490 | edge e; |
f8032688 MM |
491 | |
492 | par = di->dfs_parent[v]; | |
493 | k = v; | |
628f6a4e BE |
494 | |
495 | ei = (reverse) ? ei_start (bb->succs) : ei_start (bb->preds); | |
496 | ||
f8032688 | 497 | if (reverse) |
26e0e410 | 498 | { |
26e0e410 RH |
499 | /* If this block has a fake edge to exit, process that first. */ |
500 | if (bitmap_bit_p (di->fake_exit_edge, bb->index)) | |
501 | { | |
628f6a4e BE |
502 | einext = ei; |
503 | einext.index = 0; | |
26e0e410 RH |
504 | goto do_fake_exit_edge; |
505 | } | |
506 | } | |
f8032688 MM |
507 | |
508 | /* Search all direct predecessors for the smallest node with a path | |
509 | to them. That way we have the smallest node with also a path to | |
510 | us only over nodes behind us. In effect we search for our | |
511 | semidominator. */ | |
628f6a4e | 512 | while (!ei_end_p (ei)) |
f8032688 MM |
513 | { |
514 | TBB k1; | |
515 | basic_block b; | |
516 | ||
628f6a4e BE |
517 | e = ei_edge (ei); |
518 | b = (reverse) ? e->dest : e->src; | |
519 | einext = ei; | |
520 | ei_next (&einext); | |
521 | ||
f8032688 | 522 | if (b == en_block) |
26e0e410 RH |
523 | { |
524 | do_fake_exit_edge: | |
525 | k1 = di->dfs_order[last_basic_block]; | |
526 | } | |
f8032688 | 527 | else |
0b17ab2f | 528 | k1 = di->dfs_order[b->index]; |
f8032688 MM |
529 | |
530 | /* Call eval() only if really needed. If k1 is above V in DFS tree, | |
531 | then we know, that eval(k1) == k1 and key[k1] == k1. */ | |
532 | if (k1 > v) | |
533 | k1 = di->key[eval (di, k1)]; | |
534 | if (k1 < k) | |
535 | k = k1; | |
628f6a4e BE |
536 | |
537 | ei = einext; | |
f8032688 MM |
538 | } |
539 | ||
540 | di->key[v] = k; | |
541 | link_roots (di, par, v); | |
542 | di->next_bucket[v] = di->bucket[k]; | |
543 | di->bucket[k] = v; | |
544 | ||
545 | /* Transform semidominators into dominators. */ | |
546 | for (w = di->bucket[par]; w; w = di->next_bucket[w]) | |
547 | { | |
548 | k = eval (di, w); | |
549 | if (di->key[k] < di->key[w]) | |
550 | di->dom[w] = k; | |
551 | else | |
552 | di->dom[w] = par; | |
553 | } | |
554 | /* We don't need to cleanup next_bucket[]. */ | |
555 | di->bucket[par] = 0; | |
556 | v--; | |
557 | } | |
558 | ||
a1f300c0 | 559 | /* Explicitly define the dominators. */ |
f8032688 MM |
560 | di->dom[1] = 0; |
561 | for (v = 2; v <= di->nodes; v++) | |
562 | if (di->dom[v] != di->key[v]) | |
563 | di->dom[v] = di->dom[di->dom[v]]; | |
564 | } | |
565 | ||
d47cc544 SB |
566 | /* Assign dfs numbers starting from NUM to NODE and its sons. */ |
567 | ||
568 | static void | |
569 | assign_dfs_numbers (struct et_node *node, int *num) | |
570 | { | |
571 | struct et_node *son; | |
572 | ||
573 | node->dfs_num_in = (*num)++; | |
574 | ||
575 | if (node->son) | |
576 | { | |
577 | assign_dfs_numbers (node->son, num); | |
578 | for (son = node->son->right; son != node->son; son = son->right) | |
6de9cd9a | 579 | assign_dfs_numbers (son, num); |
d47cc544 | 580 | } |
f8032688 | 581 | |
d47cc544 SB |
582 | node->dfs_num_out = (*num)++; |
583 | } | |
f8032688 | 584 | |
5d3cc252 | 585 | /* Compute the data necessary for fast resolving of dominator queries in a |
d47cc544 | 586 | static dominator tree. */ |
f8032688 | 587 | |
d47cc544 SB |
588 | static void |
589 | compute_dom_fast_query (enum cdi_direction dir) | |
590 | { | |
591 | int num = 0; | |
592 | basic_block bb; | |
593 | ||
fce22de5 | 594 | gcc_assert (dom_info_available_p (dir)); |
d47cc544 SB |
595 | |
596 | if (dom_computed[dir] == DOM_OK) | |
597 | return; | |
598 | ||
599 | FOR_ALL_BB (bb) | |
600 | { | |
601 | if (!bb->dom[dir]->father) | |
6de9cd9a | 602 | assign_dfs_numbers (bb->dom[dir], &num); |
d47cc544 SB |
603 | } |
604 | ||
605 | dom_computed[dir] = DOM_OK; | |
606 | } | |
607 | ||
608 | /* The main entry point into this module. DIR is set depending on whether | |
609 | we want to compute dominators or postdominators. */ | |
610 | ||
611 | void | |
612 | calculate_dominance_info (enum cdi_direction dir) | |
f8032688 MM |
613 | { |
614 | struct dom_info di; | |
355be0dc JH |
615 | basic_block b; |
616 | ||
d47cc544 SB |
617 | if (dom_computed[dir] == DOM_OK) |
618 | return; | |
355be0dc | 619 | |
74c96e0c | 620 | timevar_push (TV_DOMINANCE); |
fce22de5 | 621 | if (!dom_info_available_p (dir)) |
d47cc544 | 622 | { |
ced3f397 | 623 | gcc_assert (!n_bbs_in_dom_tree[dir]); |
f8032688 | 624 | |
d47cc544 SB |
625 | FOR_ALL_BB (b) |
626 | { | |
627 | b->dom[dir] = et_new_tree (b); | |
628 | } | |
24bd1a0b | 629 | n_bbs_in_dom_tree[dir] = n_basic_blocks; |
f8032688 | 630 | |
26e0e410 | 631 | init_dom_info (&di, dir); |
d47cc544 SB |
632 | calc_dfs_tree (&di, dir); |
633 | calc_idoms (&di, dir); | |
355be0dc | 634 | |
d47cc544 SB |
635 | FOR_EACH_BB (b) |
636 | { | |
637 | TBB d = di.dom[di.dfs_order[b->index]]; | |
638 | ||
639 | if (di.dfs_to_bb[d]) | |
640 | et_set_father (b->dom[dir], di.dfs_to_bb[d]->dom[dir]); | |
641 | } | |
e0082a72 | 642 | |
d47cc544 SB |
643 | free_dom_info (&di); |
644 | dom_computed[dir] = DOM_NO_FAST_QUERY; | |
355be0dc JH |
645 | } |
646 | ||
d47cc544 | 647 | compute_dom_fast_query (dir); |
74c96e0c ZD |
648 | |
649 | timevar_pop (TV_DOMINANCE); | |
355be0dc JH |
650 | } |
651 | ||
d47cc544 | 652 | /* Free dominance information for direction DIR. */ |
355be0dc | 653 | void |
d47cc544 | 654 | free_dominance_info (enum cdi_direction dir) |
355be0dc JH |
655 | { |
656 | basic_block bb; | |
657 | ||
fce22de5 | 658 | if (!dom_info_available_p (dir)) |
d47cc544 SB |
659 | return; |
660 | ||
661 | FOR_ALL_BB (bb) | |
662 | { | |
bef87a34 KH |
663 | et_free_tree_force (bb->dom[dir]); |
664 | bb->dom[dir] = NULL; | |
d47cc544 | 665 | } |
5a6ccafd | 666 | et_free_pools (); |
d47cc544 | 667 | |
bef87a34 | 668 | n_bbs_in_dom_tree[dir] = 0; |
6de9cd9a | 669 | |
d47cc544 | 670 | dom_computed[dir] = DOM_NONE; |
355be0dc JH |
671 | } |
672 | ||
673 | /* Return the immediate dominator of basic block BB. */ | |
674 | basic_block | |
d47cc544 | 675 | get_immediate_dominator (enum cdi_direction dir, basic_block bb) |
355be0dc | 676 | { |
d47cc544 SB |
677 | struct et_node *node = bb->dom[dir]; |
678 | ||
ced3f397 | 679 | gcc_assert (dom_computed[dir]); |
d47cc544 SB |
680 | |
681 | if (!node->father) | |
682 | return NULL; | |
683 | ||
6de9cd9a | 684 | return node->father->data; |
355be0dc JH |
685 | } |
686 | ||
687 | /* Set the immediate dominator of the block possibly removing | |
688 | existing edge. NULL can be used to remove any edge. */ | |
689 | inline void | |
d47cc544 SB |
690 | set_immediate_dominator (enum cdi_direction dir, basic_block bb, |
691 | basic_block dominated_by) | |
355be0dc | 692 | { |
d47cc544 SB |
693 | struct et_node *node = bb->dom[dir]; |
694 | ||
ced3f397 | 695 | gcc_assert (dom_computed[dir]); |
355be0dc | 696 | |
d47cc544 | 697 | if (node->father) |
355be0dc | 698 | { |
d47cc544 | 699 | if (node->father->data == dominated_by) |
6de9cd9a | 700 | return; |
d47cc544 | 701 | et_split (node); |
355be0dc | 702 | } |
d47cc544 SB |
703 | |
704 | if (dominated_by) | |
705 | et_set_father (node, dominated_by->dom[dir]); | |
706 | ||
707 | if (dom_computed[dir] == DOM_OK) | |
708 | dom_computed[dir] = DOM_NO_FAST_QUERY; | |
355be0dc JH |
709 | } |
710 | ||
5d3cc252 | 711 | /* Store all basic blocks immediately dominated by BB into BBS and return |
d47cc544 | 712 | their number. */ |
355be0dc | 713 | int |
d47cc544 | 714 | get_dominated_by (enum cdi_direction dir, basic_block bb, basic_block **bbs) |
355be0dc | 715 | { |
d47cc544 SB |
716 | int n; |
717 | struct et_node *node = bb->dom[dir], *son = node->son, *ason; | |
718 | ||
ced3f397 | 719 | gcc_assert (dom_computed[dir]); |
d47cc544 SB |
720 | |
721 | if (!son) | |
722 | { | |
723 | *bbs = NULL; | |
724 | return 0; | |
725 | } | |
726 | ||
727 | for (ason = son->right, n = 1; ason != son; ason = ason->right) | |
728 | n++; | |
729 | ||
5ed6ace5 | 730 | *bbs = XNEWVEC (basic_block, n); |
d47cc544 SB |
731 | (*bbs)[0] = son->data; |
732 | for (ason = son->right, n = 1; ason != son; ason = ason->right) | |
733 | (*bbs)[n++] = ason->data; | |
355be0dc | 734 | |
355be0dc JH |
735 | return n; |
736 | } | |
737 | ||
42759f1e ZD |
738 | /* Find all basic blocks that are immediately dominated (in direction DIR) |
739 | by some block between N_REGION ones stored in REGION, except for blocks | |
740 | in the REGION itself. The found blocks are stored to DOMS and their number | |
741 | is returned. */ | |
742 | ||
743 | unsigned | |
744 | get_dominated_by_region (enum cdi_direction dir, basic_block *region, | |
745 | unsigned n_region, basic_block *doms) | |
746 | { | |
747 | unsigned n_doms = 0, i; | |
748 | basic_block dom; | |
749 | ||
750 | for (i = 0; i < n_region; i++) | |
6580ee77 | 751 | region[i]->flags |= BB_DUPLICATED; |
42759f1e ZD |
752 | for (i = 0; i < n_region; i++) |
753 | for (dom = first_dom_son (dir, region[i]); | |
754 | dom; | |
755 | dom = next_dom_son (dir, dom)) | |
6580ee77 | 756 | if (!(dom->flags & BB_DUPLICATED)) |
42759f1e ZD |
757 | doms[n_doms++] = dom; |
758 | for (i = 0; i < n_region; i++) | |
6580ee77 | 759 | region[i]->flags &= ~BB_DUPLICATED; |
42759f1e ZD |
760 | |
761 | return n_doms; | |
762 | } | |
763 | ||
355be0dc JH |
764 | /* Redirect all edges pointing to BB to TO. */ |
765 | void | |
d47cc544 SB |
766 | redirect_immediate_dominators (enum cdi_direction dir, basic_block bb, |
767 | basic_block to) | |
355be0dc | 768 | { |
d47cc544 SB |
769 | struct et_node *bb_node = bb->dom[dir], *to_node = to->dom[dir], *son; |
770 | ||
ced3f397 | 771 | gcc_assert (dom_computed[dir]); |
355be0dc | 772 | |
d47cc544 SB |
773 | if (!bb_node->son) |
774 | return; | |
775 | ||
776 | while (bb_node->son) | |
355be0dc | 777 | { |
d47cc544 SB |
778 | son = bb_node->son; |
779 | ||
780 | et_split (son); | |
781 | et_set_father (son, to_node); | |
355be0dc | 782 | } |
d47cc544 SB |
783 | |
784 | if (dom_computed[dir] == DOM_OK) | |
785 | dom_computed[dir] = DOM_NO_FAST_QUERY; | |
355be0dc JH |
786 | } |
787 | ||
788 | /* Find first basic block in the tree dominating both BB1 and BB2. */ | |
789 | basic_block | |
d47cc544 | 790 | nearest_common_dominator (enum cdi_direction dir, basic_block bb1, basic_block bb2) |
355be0dc | 791 | { |
ced3f397 | 792 | gcc_assert (dom_computed[dir]); |
d47cc544 | 793 | |
355be0dc JH |
794 | if (!bb1) |
795 | return bb2; | |
796 | if (!bb2) | |
797 | return bb1; | |
d47cc544 SB |
798 | |
799 | return et_nca (bb1->dom[dir], bb2->dom[dir])->data; | |
355be0dc JH |
800 | } |
801 | ||
0bca51f0 DN |
802 | |
803 | /* Find the nearest common dominator for the basic blocks in BLOCKS, | |
804 | using dominance direction DIR. */ | |
805 | ||
806 | basic_block | |
807 | nearest_common_dominator_for_set (enum cdi_direction dir, bitmap blocks) | |
808 | { | |
809 | unsigned i, first; | |
810 | bitmap_iterator bi; | |
811 | basic_block dom; | |
812 | ||
813 | first = bitmap_first_set_bit (blocks); | |
814 | dom = BASIC_BLOCK (first); | |
815 | EXECUTE_IF_SET_IN_BITMAP (blocks, 0, i, bi) | |
816 | if (dom != BASIC_BLOCK (i)) | |
817 | dom = nearest_common_dominator (dir, dom, BASIC_BLOCK (i)); | |
818 | ||
819 | return dom; | |
820 | } | |
821 | ||
b629276a DB |
822 | /* Given a dominator tree, we can determine whether one thing |
823 | dominates another in constant time by using two DFS numbers: | |
824 | ||
825 | 1. The number for when we visit a node on the way down the tree | |
826 | 2. The number for when we visit a node on the way back up the tree | |
827 | ||
828 | You can view these as bounds for the range of dfs numbers the | |
829 | nodes in the subtree of the dominator tree rooted at that node | |
830 | will contain. | |
831 | ||
832 | The dominator tree is always a simple acyclic tree, so there are | |
833 | only three possible relations two nodes in the dominator tree have | |
834 | to each other: | |
835 | ||
836 | 1. Node A is above Node B (and thus, Node A dominates node B) | |
837 | ||
838 | A | |
839 | | | |
840 | C | |
841 | / \ | |
842 | B D | |
843 | ||
844 | ||
845 | In the above case, DFS_Number_In of A will be <= DFS_Number_In of | |
846 | B, and DFS_Number_Out of A will be >= DFS_Number_Out of B. This is | |
847 | because we must hit A in the dominator tree *before* B on the walk | |
848 | down, and we will hit A *after* B on the walk back up | |
849 | ||
d8701f02 | 850 | 2. Node A is below node B (and thus, node B dominates node A) |
b629276a DB |
851 | |
852 | ||
853 | B | |
854 | | | |
855 | A | |
856 | / \ | |
857 | C D | |
858 | ||
859 | In the above case, DFS_Number_In of A will be >= DFS_Number_In of | |
860 | B, and DFS_Number_Out of A will be <= DFS_Number_Out of B. | |
861 | ||
862 | This is because we must hit A in the dominator tree *after* B on | |
863 | the walk down, and we will hit A *before* B on the walk back up | |
864 | ||
865 | 3. Node A and B are siblings (and thus, neither dominates the other) | |
866 | ||
867 | C | |
868 | | | |
869 | D | |
870 | / \ | |
871 | A B | |
872 | ||
873 | In the above case, DFS_Number_In of A will *always* be <= | |
874 | DFS_Number_In of B, and DFS_Number_Out of A will *always* be <= | |
875 | DFS_Number_Out of B. This is because we will always finish the dfs | |
876 | walk of one of the subtrees before the other, and thus, the dfs | |
877 | numbers for one subtree can't intersect with the range of dfs | |
878 | numbers for the other subtree. If you swap A and B's position in | |
879 | the dominator tree, the comparison changes direction, but the point | |
880 | is that both comparisons will always go the same way if there is no | |
881 | dominance relationship. | |
882 | ||
883 | Thus, it is sufficient to write | |
884 | ||
885 | A_Dominates_B (node A, node B) | |
886 | { | |
887 | return DFS_Number_In(A) <= DFS_Number_In(B) | |
888 | && DFS_Number_Out (A) >= DFS_Number_Out(B); | |
889 | } | |
890 | ||
891 | A_Dominated_by_B (node A, node B) | |
892 | { | |
893 | return DFS_Number_In(A) >= DFS_Number_In(A) | |
894 | && DFS_Number_Out (A) <= DFS_Number_Out(B); | |
895 | } */ | |
0bca51f0 | 896 | |
355be0dc JH |
897 | /* Return TRUE in case BB1 is dominated by BB2. */ |
898 | bool | |
d47cc544 | 899 | dominated_by_p (enum cdi_direction dir, basic_block bb1, basic_block bb2) |
6de9cd9a | 900 | { |
d47cc544 SB |
901 | struct et_node *n1 = bb1->dom[dir], *n2 = bb2->dom[dir]; |
902 | ||
ced3f397 | 903 | gcc_assert (dom_computed[dir]); |
d47cc544 SB |
904 | |
905 | if (dom_computed[dir] == DOM_OK) | |
906 | return (n1->dfs_num_in >= n2->dfs_num_in | |
6de9cd9a | 907 | && n1->dfs_num_out <= n2->dfs_num_out); |
d47cc544 SB |
908 | |
909 | return et_below (n1, n2); | |
355be0dc JH |
910 | } |
911 | ||
f074ff6c ZD |
912 | /* Returns the entry dfs number for basic block BB, in the direction DIR. */ |
913 | ||
914 | unsigned | |
915 | bb_dom_dfs_in (enum cdi_direction dir, basic_block bb) | |
916 | { | |
917 | struct et_node *n = bb->dom[dir]; | |
918 | ||
919 | gcc_assert (dom_computed[dir] == DOM_OK); | |
920 | return n->dfs_num_in; | |
921 | } | |
922 | ||
923 | /* Returns the exit dfs number for basic block BB, in the direction DIR. */ | |
924 | ||
925 | unsigned | |
926 | bb_dom_dfs_out (enum cdi_direction dir, basic_block bb) | |
927 | { | |
928 | struct et_node *n = bb->dom[dir]; | |
929 | ||
930 | gcc_assert (dom_computed[dir] == DOM_OK); | |
931 | return n->dfs_num_out; | |
932 | } | |
933 | ||
355be0dc JH |
934 | /* Verify invariants of dominator structure. */ |
935 | void | |
d47cc544 | 936 | verify_dominators (enum cdi_direction dir) |
355be0dc JH |
937 | { |
938 | int err = 0; | |
939 | basic_block bb; | |
940 | ||
fce22de5 | 941 | gcc_assert (dom_info_available_p (dir)); |
d47cc544 | 942 | |
355be0dc JH |
943 | FOR_EACH_BB (bb) |
944 | { | |
945 | basic_block dom_bb; | |
df485d80 | 946 | basic_block imm_bb; |
355be0dc | 947 | |
d47cc544 | 948 | dom_bb = recount_dominator (dir, bb); |
df485d80 FCE |
949 | imm_bb = get_immediate_dominator (dir, bb); |
950 | if (dom_bb != imm_bb) | |
f8032688 | 951 | { |
df485d80 FCE |
952 | if ((dom_bb == NULL) || (imm_bb == NULL)) |
953 | error ("dominator of %d status unknown", bb->index); | |
08fb229e FCE |
954 | else |
955 | error ("dominator of %d should be %d, not %d", | |
df485d80 | 956 | bb->index, dom_bb->index, imm_bb->index); |
355be0dc JH |
957 | err = 1; |
958 | } | |
959 | } | |
e7bd94cc | 960 | |
fce22de5 | 961 | if (dir == CDI_DOMINATORS) |
e7bd94cc ZD |
962 | { |
963 | FOR_EACH_BB (bb) | |
964 | { | |
965 | if (!dominated_by_p (dir, bb, ENTRY_BLOCK_PTR)) | |
966 | { | |
967 | error ("ENTRY does not dominate bb %d", bb->index); | |
968 | err = 1; | |
969 | } | |
970 | } | |
971 | } | |
972 | ||
ced3f397 | 973 | gcc_assert (!err); |
355be0dc JH |
974 | } |
975 | ||
738ed977 ZD |
976 | /* Determine immediate dominator (or postdominator, according to DIR) of BB, |
977 | assuming that dominators of other blocks are correct. We also use it to | |
978 | recompute the dominators in a restricted area, by iterating it until it | |
71cc389b | 979 | reaches a fixed point. */ |
738ed977 | 980 | |
355be0dc | 981 | basic_block |
d47cc544 | 982 | recount_dominator (enum cdi_direction dir, basic_block bb) |
355be0dc | 983 | { |
738ed977 ZD |
984 | basic_block dom_bb = NULL; |
985 | edge e; | |
628f6a4e | 986 | edge_iterator ei; |
355be0dc | 987 | |
ced3f397 | 988 | gcc_assert (dom_computed[dir]); |
d47cc544 | 989 | |
738ed977 ZD |
990 | if (dir == CDI_DOMINATORS) |
991 | { | |
628f6a4e | 992 | FOR_EACH_EDGE (e, ei, bb->preds) |
738ed977 | 993 | { |
e7bd94cc ZD |
994 | /* Ignore the predecessors that either are not reachable from |
995 | the entry block, or whose dominator was not determined yet. */ | |
996 | if (!dominated_by_p (dir, e->src, ENTRY_BLOCK_PTR)) | |
997 | continue; | |
998 | ||
738ed977 ZD |
999 | if (!dominated_by_p (dir, e->src, bb)) |
1000 | dom_bb = nearest_common_dominator (dir, dom_bb, e->src); | |
1001 | } | |
1002 | } | |
1003 | else | |
1004 | { | |
628f6a4e | 1005 | FOR_EACH_EDGE (e, ei, bb->succs) |
738ed977 ZD |
1006 | { |
1007 | if (!dominated_by_p (dir, e->dest, bb)) | |
1008 | dom_bb = nearest_common_dominator (dir, dom_bb, e->dest); | |
1009 | } | |
1010 | } | |
f8032688 | 1011 | |
738ed977 | 1012 | return dom_bb; |
355be0dc JH |
1013 | } |
1014 | ||
1015 | /* Iteratively recount dominators of BBS. The change is supposed to be local | |
1016 | and not to grow further. */ | |
1017 | void | |
d47cc544 | 1018 | iterate_fix_dominators (enum cdi_direction dir, basic_block *bbs, int n) |
355be0dc JH |
1019 | { |
1020 | int i, changed = 1; | |
1021 | basic_block old_dom, new_dom; | |
1022 | ||
ced3f397 | 1023 | gcc_assert (dom_computed[dir]); |
d47cc544 | 1024 | |
e7bd94cc ZD |
1025 | for (i = 0; i < n; i++) |
1026 | set_immediate_dominator (dir, bbs[i], NULL); | |
1027 | ||
355be0dc JH |
1028 | while (changed) |
1029 | { | |
1030 | changed = 0; | |
1031 | for (i = 0; i < n; i++) | |
1032 | { | |
d47cc544 SB |
1033 | old_dom = get_immediate_dominator (dir, bbs[i]); |
1034 | new_dom = recount_dominator (dir, bbs[i]); | |
355be0dc JH |
1035 | if (old_dom != new_dom) |
1036 | { | |
1037 | changed = 1; | |
d47cc544 | 1038 | set_immediate_dominator (dir, bbs[i], new_dom); |
355be0dc | 1039 | } |
f8032688 MM |
1040 | } |
1041 | } | |
e7bd94cc ZD |
1042 | |
1043 | for (i = 0; i < n; i++) | |
ced3f397 | 1044 | gcc_assert (get_immediate_dominator (dir, bbs[i])); |
355be0dc | 1045 | } |
f8032688 | 1046 | |
355be0dc | 1047 | void |
d47cc544 | 1048 | add_to_dominance_info (enum cdi_direction dir, basic_block bb) |
355be0dc | 1049 | { |
ced3f397 NS |
1050 | gcc_assert (dom_computed[dir]); |
1051 | gcc_assert (!bb->dom[dir]); | |
d47cc544 | 1052 | |
6de9cd9a DN |
1053 | n_bbs_in_dom_tree[dir]++; |
1054 | ||
d47cc544 SB |
1055 | bb->dom[dir] = et_new_tree (bb); |
1056 | ||
1057 | if (dom_computed[dir] == DOM_OK) | |
1058 | dom_computed[dir] = DOM_NO_FAST_QUERY; | |
355be0dc JH |
1059 | } |
1060 | ||
1061 | void | |
d47cc544 SB |
1062 | delete_from_dominance_info (enum cdi_direction dir, basic_block bb) |
1063 | { | |
ced3f397 | 1064 | gcc_assert (dom_computed[dir]); |
d47cc544 SB |
1065 | |
1066 | et_free_tree (bb->dom[dir]); | |
1067 | bb->dom[dir] = NULL; | |
6de9cd9a | 1068 | n_bbs_in_dom_tree[dir]--; |
d47cc544 SB |
1069 | |
1070 | if (dom_computed[dir] == DOM_OK) | |
1071 | dom_computed[dir] = DOM_NO_FAST_QUERY; | |
1072 | } | |
1073 | ||
1074 | /* Returns the first son of BB in the dominator or postdominator tree | |
1075 | as determined by DIR. */ | |
1076 | ||
1077 | basic_block | |
1078 | first_dom_son (enum cdi_direction dir, basic_block bb) | |
355be0dc | 1079 | { |
d47cc544 SB |
1080 | struct et_node *son = bb->dom[dir]->son; |
1081 | ||
1082 | return son ? son->data : NULL; | |
1083 | } | |
1084 | ||
1085 | /* Returns the next dominance son after BB in the dominator or postdominator | |
1086 | tree as determined by DIR, or NULL if it was the last one. */ | |
1087 | ||
1088 | basic_block | |
1089 | next_dom_son (enum cdi_direction dir, basic_block bb) | |
1090 | { | |
1091 | struct et_node *next = bb->dom[dir]->right; | |
1092 | ||
1093 | return next->father->son == next ? NULL : next->data; | |
355be0dc JH |
1094 | } |
1095 | ||
fce22de5 ZD |
1096 | /* Returns true if dominance information for direction DIR is available. */ |
1097 | ||
1098 | bool | |
1099 | dom_info_available_p (enum cdi_direction dir) | |
1100 | { | |
1101 | return dom_computed[dir] != DOM_NONE; | |
1102 | } | |
1103 | ||
355be0dc | 1104 | void |
d47cc544 | 1105 | debug_dominance_info (enum cdi_direction dir) |
355be0dc JH |
1106 | { |
1107 | basic_block bb, bb2; | |
1108 | FOR_EACH_BB (bb) | |
d47cc544 | 1109 | if ((bb2 = get_immediate_dominator (dir, bb))) |
355be0dc | 1110 | fprintf (stderr, "%i %i\n", bb->index, bb2->index); |
f8032688 | 1111 | } |