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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 | 48 | /* Whether the dominators and the postdominators are available. */ |
2b28c07a | 49 | static 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 | 116 | static void free_dom_info (struct dom_info *); |
2b28c07a JC |
117 | static void calc_dfs_tree_nonrec (struct dom_info *, basic_block, bool); |
118 | static void calc_dfs_tree (struct dom_info *, bool); | |
7080f735 AJ |
119 | static void compress (struct dom_info *, TBB); |
120 | static TBB eval (struct dom_info *, TBB); | |
121 | static void link_roots (struct dom_info *, TBB, TBB); | |
2b28c07a | 122 | static void calc_idoms (struct dom_info *, bool); |
d47cc544 | 123 | void debug_dominance_info (enum cdi_direction); |
f8032688 | 124 | |
6de9cd9a DN |
125 | /* Keeps track of the*/ |
126 | static unsigned n_bbs_in_dom_tree[2]; | |
127 | ||
f8032688 MM |
128 | /* Helper macro for allocating and initializing an array, |
129 | for aesthetic reasons. */ | |
130 | #define init_ar(var, type, num, content) \ | |
3a538a66 KH |
131 | do \ |
132 | { \ | |
133 | unsigned int i = 1; /* Catch content == i. */ \ | |
134 | if (! (content)) \ | |
5ed6ace5 | 135 | (var) = XCNEWVEC (type, num); \ |
3a538a66 KH |
136 | else \ |
137 | { \ | |
5ed6ace5 | 138 | (var) = XNEWVEC (type, (num)); \ |
3a538a66 KH |
139 | for (i = 0; i < num; i++) \ |
140 | (var)[i] = (content); \ | |
141 | } \ | |
142 | } \ | |
143 | while (0) | |
f8032688 MM |
144 | |
145 | /* Allocate all needed memory in a pessimistic fashion (so we round up). | |
4912a07c | 146 | This initializes the contents of DI, which already must be allocated. */ |
f8032688 MM |
147 | |
148 | static void | |
26e0e410 | 149 | init_dom_info (struct dom_info *di, enum cdi_direction dir) |
f8032688 | 150 | { |
24bd1a0b | 151 | unsigned int num = n_basic_blocks; |
f8032688 MM |
152 | init_ar (di->dfs_parent, TBB, num, 0); |
153 | init_ar (di->path_min, TBB, num, i); | |
154 | init_ar (di->key, TBB, num, i); | |
155 | init_ar (di->dom, TBB, num, 0); | |
156 | ||
157 | init_ar (di->bucket, TBB, num, 0); | |
158 | init_ar (di->next_bucket, TBB, num, 0); | |
159 | ||
160 | init_ar (di->set_chain, TBB, num, 0); | |
161 | init_ar (di->set_size, unsigned int, num, 1); | |
162 | init_ar (di->set_child, TBB, num, 0); | |
163 | ||
d55bc081 | 164 | init_ar (di->dfs_order, TBB, (unsigned int) last_basic_block + 1, 0); |
f8032688 MM |
165 | init_ar (di->dfs_to_bb, basic_block, num, 0); |
166 | ||
167 | di->dfsnum = 1; | |
168 | di->nodes = 0; | |
26e0e410 | 169 | |
2b28c07a JC |
170 | switch (dir) |
171 | { | |
172 | case CDI_DOMINATORS: | |
173 | di->fake_exit_edge = NULL; | |
174 | break; | |
175 | case CDI_POST_DOMINATORS: | |
176 | di->fake_exit_edge = BITMAP_ALLOC (NULL); | |
177 | break; | |
178 | default: | |
179 | gcc_unreachable (); | |
180 | break; | |
181 | } | |
f8032688 MM |
182 | } |
183 | ||
184 | #undef init_ar | |
185 | ||
2b28c07a JC |
186 | /* Map dominance calculation type to array index used for various |
187 | dominance information arrays. This version is simple -- it will need | |
188 | to be modified, obviously, if additional values are added to | |
189 | cdi_direction. */ | |
190 | ||
191 | static unsigned int | |
192 | dom_convert_dir_to_idx (enum cdi_direction dir) | |
193 | { | |
194 | gcc_assert (dir == CDI_DOMINATORS || dir == CDI_POST_DOMINATORS); | |
195 | return dir - 1; | |
196 | } | |
197 | ||
f8032688 MM |
198 | /* Free all allocated memory in DI, but not DI itself. */ |
199 | ||
200 | static void | |
7080f735 | 201 | free_dom_info (struct dom_info *di) |
f8032688 MM |
202 | { |
203 | free (di->dfs_parent); | |
204 | free (di->path_min); | |
205 | free (di->key); | |
206 | free (di->dom); | |
207 | free (di->bucket); | |
208 | free (di->next_bucket); | |
209 | free (di->set_chain); | |
210 | free (di->set_size); | |
211 | free (di->set_child); | |
212 | free (di->dfs_order); | |
213 | free (di->dfs_to_bb); | |
8bdbfff5 | 214 | BITMAP_FREE (di->fake_exit_edge); |
f8032688 MM |
215 | } |
216 | ||
217 | /* The nonrecursive variant of creating a DFS tree. DI is our working | |
218 | structure, BB the starting basic block for this tree and REVERSE | |
219 | is true, if predecessors should be visited instead of successors of a | |
220 | node. After this is done all nodes reachable from BB were visited, have | |
221 | assigned their dfs number and are linked together to form a tree. */ | |
222 | ||
223 | static void | |
2b28c07a | 224 | calc_dfs_tree_nonrec (struct dom_info *di, basic_block bb, bool reverse) |
f8032688 | 225 | { |
f8032688 MM |
226 | /* We call this _only_ if bb is not already visited. */ |
227 | edge e; | |
228 | TBB child_i, my_i = 0; | |
628f6a4e BE |
229 | edge_iterator *stack; |
230 | edge_iterator ei, einext; | |
f8032688 MM |
231 | int sp; |
232 | /* Start block (ENTRY_BLOCK_PTR for forward problem, EXIT_BLOCK for backward | |
233 | problem). */ | |
234 | basic_block en_block; | |
235 | /* Ending block. */ | |
236 | basic_block ex_block; | |
237 | ||
5ed6ace5 | 238 | stack = XNEWVEC (edge_iterator, n_basic_blocks + 1); |
f8032688 MM |
239 | sp = 0; |
240 | ||
241 | /* Initialize our border blocks, and the first edge. */ | |
242 | if (reverse) | |
243 | { | |
628f6a4e | 244 | ei = ei_start (bb->preds); |
f8032688 MM |
245 | en_block = EXIT_BLOCK_PTR; |
246 | ex_block = ENTRY_BLOCK_PTR; | |
247 | } | |
248 | else | |
249 | { | |
628f6a4e | 250 | ei = ei_start (bb->succs); |
f8032688 MM |
251 | en_block = ENTRY_BLOCK_PTR; |
252 | ex_block = EXIT_BLOCK_PTR; | |
253 | } | |
254 | ||
255 | /* When the stack is empty we break out of this loop. */ | |
256 | while (1) | |
257 | { | |
258 | basic_block bn; | |
259 | ||
260 | /* This loop traverses edges e in depth first manner, and fills the | |
261 | stack. */ | |
628f6a4e | 262 | while (!ei_end_p (ei)) |
f8032688 | 263 | { |
628f6a4e | 264 | e = ei_edge (ei); |
f8032688 MM |
265 | |
266 | /* Deduce from E the current and the next block (BB and BN), and the | |
267 | next edge. */ | |
268 | if (reverse) | |
269 | { | |
270 | bn = e->src; | |
271 | ||
272 | /* If the next node BN is either already visited or a border | |
273 | block the current edge is useless, and simply overwritten | |
274 | with the next edge out of the current node. */ | |
0b17ab2f | 275 | if (bn == ex_block || di->dfs_order[bn->index]) |
f8032688 | 276 | { |
628f6a4e | 277 | ei_next (&ei); |
f8032688 MM |
278 | continue; |
279 | } | |
280 | bb = e->dest; | |
628f6a4e | 281 | einext = ei_start (bn->preds); |
f8032688 MM |
282 | } |
283 | else | |
284 | { | |
285 | bn = e->dest; | |
0b17ab2f | 286 | if (bn == ex_block || di->dfs_order[bn->index]) |
f8032688 | 287 | { |
628f6a4e | 288 | ei_next (&ei); |
f8032688 MM |
289 | continue; |
290 | } | |
291 | bb = e->src; | |
628f6a4e | 292 | einext = ei_start (bn->succs); |
f8032688 MM |
293 | } |
294 | ||
ced3f397 | 295 | gcc_assert (bn != en_block); |
f8032688 MM |
296 | |
297 | /* Fill the DFS tree info calculatable _before_ recursing. */ | |
298 | if (bb != en_block) | |
0b17ab2f | 299 | my_i = di->dfs_order[bb->index]; |
f8032688 | 300 | else |
d55bc081 | 301 | my_i = di->dfs_order[last_basic_block]; |
0b17ab2f | 302 | child_i = di->dfs_order[bn->index] = di->dfsnum++; |
f8032688 MM |
303 | di->dfs_to_bb[child_i] = bn; |
304 | di->dfs_parent[child_i] = my_i; | |
305 | ||
306 | /* Save the current point in the CFG on the stack, and recurse. */ | |
628f6a4e BE |
307 | stack[sp++] = ei; |
308 | ei = einext; | |
f8032688 MM |
309 | } |
310 | ||
311 | if (!sp) | |
312 | break; | |
628f6a4e | 313 | ei = stack[--sp]; |
f8032688 MM |
314 | |
315 | /* OK. The edge-list was exhausted, meaning normally we would | |
316 | end the recursion. After returning from the recursive call, | |
317 | there were (may be) other statements which were run after a | |
318 | child node was completely considered by DFS. Here is the | |
319 | point to do it in the non-recursive variant. | |
320 | E.g. The block just completed is in e->dest for forward DFS, | |
321 | the block not yet completed (the parent of the one above) | |
322 | in e->src. This could be used e.g. for computing the number of | |
323 | descendants or the tree depth. */ | |
628f6a4e | 324 | ei_next (&ei); |
f8032688 MM |
325 | } |
326 | free (stack); | |
327 | } | |
328 | ||
329 | /* The main entry for calculating the DFS tree or forest. DI is our working | |
330 | structure and REVERSE is true, if we are interested in the reverse flow | |
331 | graph. In that case the result is not necessarily a tree but a forest, | |
332 | because there may be nodes from which the EXIT_BLOCK is unreachable. */ | |
333 | ||
334 | static void | |
2b28c07a | 335 | calc_dfs_tree (struct dom_info *di, bool reverse) |
f8032688 MM |
336 | { |
337 | /* The first block is the ENTRY_BLOCK (or EXIT_BLOCK if REVERSE). */ | |
338 | basic_block begin = reverse ? EXIT_BLOCK_PTR : ENTRY_BLOCK_PTR; | |
d55bc081 | 339 | di->dfs_order[last_basic_block] = di->dfsnum; |
f8032688 MM |
340 | di->dfs_to_bb[di->dfsnum] = begin; |
341 | di->dfsnum++; | |
342 | ||
343 | calc_dfs_tree_nonrec (di, begin, reverse); | |
344 | ||
345 | if (reverse) | |
346 | { | |
347 | /* In the post-dom case we may have nodes without a path to EXIT_BLOCK. | |
348 | They are reverse-unreachable. In the dom-case we disallow such | |
26e0e410 RH |
349 | nodes, but in post-dom we have to deal with them. |
350 | ||
351 | There are two situations in which this occurs. First, noreturn | |
352 | functions. Second, infinite loops. In the first case we need to | |
353 | pretend that there is an edge to the exit block. In the second | |
354 | case, we wind up with a forest. We need to process all noreturn | |
355 | blocks before we know if we've got any infinite loops. */ | |
356 | ||
e0082a72 | 357 | basic_block b; |
26e0e410 RH |
358 | bool saw_unconnected = false; |
359 | ||
e0082a72 | 360 | FOR_EACH_BB_REVERSE (b) |
f8032688 | 361 | { |
628f6a4e | 362 | if (EDGE_COUNT (b->succs) > 0) |
26e0e410 RH |
363 | { |
364 | if (di->dfs_order[b->index] == 0) | |
365 | saw_unconnected = true; | |
366 | continue; | |
367 | } | |
368 | bitmap_set_bit (di->fake_exit_edge, b->index); | |
0b17ab2f | 369 | di->dfs_order[b->index] = di->dfsnum; |
f8032688 | 370 | di->dfs_to_bb[di->dfsnum] = b; |
26e0e410 | 371 | di->dfs_parent[di->dfsnum] = di->dfs_order[last_basic_block]; |
f8032688 MM |
372 | di->dfsnum++; |
373 | calc_dfs_tree_nonrec (di, b, reverse); | |
374 | } | |
26e0e410 RH |
375 | |
376 | if (saw_unconnected) | |
377 | { | |
378 | FOR_EACH_BB_REVERSE (b) | |
379 | { | |
380 | if (di->dfs_order[b->index]) | |
381 | continue; | |
382 | bitmap_set_bit (di->fake_exit_edge, b->index); | |
383 | di->dfs_order[b->index] = di->dfsnum; | |
384 | di->dfs_to_bb[di->dfsnum] = b; | |
385 | di->dfs_parent[di->dfsnum] = di->dfs_order[last_basic_block]; | |
386 | di->dfsnum++; | |
387 | calc_dfs_tree_nonrec (di, b, reverse); | |
388 | } | |
389 | } | |
f8032688 MM |
390 | } |
391 | ||
392 | di->nodes = di->dfsnum - 1; | |
393 | ||
24bd1a0b DB |
394 | /* This aborts e.g. when there is _no_ path from ENTRY to EXIT at all. */ |
395 | gcc_assert (di->nodes == (unsigned int) n_basic_blocks - 1); | |
f8032688 MM |
396 | } |
397 | ||
398 | /* Compress the path from V to the root of its set and update path_min at the | |
399 | same time. After compress(di, V) set_chain[V] is the root of the set V is | |
400 | in and path_min[V] is the node with the smallest key[] value on the path | |
401 | from V to that root. */ | |
402 | ||
403 | static void | |
7080f735 | 404 | compress (struct dom_info *di, TBB v) |
f8032688 MM |
405 | { |
406 | /* Btw. It's not worth to unrecurse compress() as the depth is usually not | |
407 | greater than 5 even for huge graphs (I've not seen call depth > 4). | |
408 | Also performance wise compress() ranges _far_ behind eval(). */ | |
409 | TBB parent = di->set_chain[v]; | |
410 | if (di->set_chain[parent]) | |
411 | { | |
412 | compress (di, parent); | |
413 | if (di->key[di->path_min[parent]] < di->key[di->path_min[v]]) | |
414 | di->path_min[v] = di->path_min[parent]; | |
415 | di->set_chain[v] = di->set_chain[parent]; | |
416 | } | |
417 | } | |
418 | ||
419 | /* Compress the path from V to the set root of V if needed (when the root has | |
420 | changed since the last call). Returns the node with the smallest key[] | |
421 | value on the path from V to the root. */ | |
422 | ||
423 | static inline TBB | |
7080f735 | 424 | eval (struct dom_info *di, TBB v) |
f8032688 MM |
425 | { |
426 | /* The representant of the set V is in, also called root (as the set | |
427 | representation is a tree). */ | |
428 | TBB rep = di->set_chain[v]; | |
429 | ||
430 | /* V itself is the root. */ | |
431 | if (!rep) | |
432 | return di->path_min[v]; | |
433 | ||
434 | /* Compress only if necessary. */ | |
435 | if (di->set_chain[rep]) | |
436 | { | |
437 | compress (di, v); | |
438 | rep = di->set_chain[v]; | |
439 | } | |
440 | ||
441 | if (di->key[di->path_min[rep]] >= di->key[di->path_min[v]]) | |
442 | return di->path_min[v]; | |
443 | else | |
444 | return di->path_min[rep]; | |
445 | } | |
446 | ||
447 | /* This essentially merges the two sets of V and W, giving a single set with | |
448 | the new root V. The internal representation of these disjoint sets is a | |
449 | balanced tree. Currently link(V,W) is only used with V being the parent | |
450 | of W. */ | |
451 | ||
452 | static void | |
7080f735 | 453 | link_roots (struct dom_info *di, TBB v, TBB w) |
f8032688 MM |
454 | { |
455 | TBB s = w; | |
456 | ||
457 | /* Rebalance the tree. */ | |
458 | while (di->key[di->path_min[w]] < di->key[di->path_min[di->set_child[s]]]) | |
459 | { | |
460 | if (di->set_size[s] + di->set_size[di->set_child[di->set_child[s]]] | |
461 | >= 2 * di->set_size[di->set_child[s]]) | |
462 | { | |
463 | di->set_chain[di->set_child[s]] = s; | |
464 | di->set_child[s] = di->set_child[di->set_child[s]]; | |
465 | } | |
466 | else | |
467 | { | |
468 | di->set_size[di->set_child[s]] = di->set_size[s]; | |
469 | s = di->set_chain[s] = di->set_child[s]; | |
470 | } | |
471 | } | |
472 | ||
473 | di->path_min[s] = di->path_min[w]; | |
474 | di->set_size[v] += di->set_size[w]; | |
475 | if (di->set_size[v] < 2 * di->set_size[w]) | |
476 | { | |
477 | TBB tmp = s; | |
478 | s = di->set_child[v]; | |
479 | di->set_child[v] = tmp; | |
480 | } | |
481 | ||
482 | /* Merge all subtrees. */ | |
483 | while (s) | |
484 | { | |
485 | di->set_chain[s] = v; | |
486 | s = di->set_child[s]; | |
487 | } | |
488 | } | |
489 | ||
490 | /* This calculates the immediate dominators (or post-dominators if REVERSE is | |
491 | true). DI is our working structure and should hold the DFS forest. | |
492 | On return the immediate dominator to node V is in di->dom[V]. */ | |
493 | ||
494 | static void | |
2b28c07a | 495 | calc_idoms (struct dom_info *di, bool reverse) |
f8032688 MM |
496 | { |
497 | TBB v, w, k, par; | |
498 | basic_block en_block; | |
628f6a4e BE |
499 | edge_iterator ei, einext; |
500 | ||
f8032688 MM |
501 | if (reverse) |
502 | en_block = EXIT_BLOCK_PTR; | |
503 | else | |
504 | en_block = ENTRY_BLOCK_PTR; | |
505 | ||
506 | /* Go backwards in DFS order, to first look at the leafs. */ | |
507 | v = di->nodes; | |
508 | while (v > 1) | |
509 | { | |
510 | basic_block bb = di->dfs_to_bb[v]; | |
628f6a4e | 511 | edge e; |
f8032688 MM |
512 | |
513 | par = di->dfs_parent[v]; | |
514 | k = v; | |
628f6a4e BE |
515 | |
516 | ei = (reverse) ? ei_start (bb->succs) : ei_start (bb->preds); | |
517 | ||
f8032688 | 518 | if (reverse) |
26e0e410 | 519 | { |
26e0e410 RH |
520 | /* If this block has a fake edge to exit, process that first. */ |
521 | if (bitmap_bit_p (di->fake_exit_edge, bb->index)) | |
522 | { | |
628f6a4e BE |
523 | einext = ei; |
524 | einext.index = 0; | |
26e0e410 RH |
525 | goto do_fake_exit_edge; |
526 | } | |
527 | } | |
f8032688 MM |
528 | |
529 | /* Search all direct predecessors for the smallest node with a path | |
530 | to them. That way we have the smallest node with also a path to | |
531 | us only over nodes behind us. In effect we search for our | |
532 | semidominator. */ | |
628f6a4e | 533 | while (!ei_end_p (ei)) |
f8032688 MM |
534 | { |
535 | TBB k1; | |
536 | basic_block b; | |
537 | ||
628f6a4e BE |
538 | e = ei_edge (ei); |
539 | b = (reverse) ? e->dest : e->src; | |
540 | einext = ei; | |
541 | ei_next (&einext); | |
542 | ||
f8032688 | 543 | if (b == en_block) |
26e0e410 RH |
544 | { |
545 | do_fake_exit_edge: | |
546 | k1 = di->dfs_order[last_basic_block]; | |
547 | } | |
f8032688 | 548 | else |
0b17ab2f | 549 | k1 = di->dfs_order[b->index]; |
f8032688 MM |
550 | |
551 | /* Call eval() only if really needed. If k1 is above V in DFS tree, | |
552 | then we know, that eval(k1) == k1 and key[k1] == k1. */ | |
553 | if (k1 > v) | |
554 | k1 = di->key[eval (di, k1)]; | |
555 | if (k1 < k) | |
556 | k = k1; | |
628f6a4e BE |
557 | |
558 | ei = einext; | |
f8032688 MM |
559 | } |
560 | ||
561 | di->key[v] = k; | |
562 | link_roots (di, par, v); | |
563 | di->next_bucket[v] = di->bucket[k]; | |
564 | di->bucket[k] = v; | |
565 | ||
566 | /* Transform semidominators into dominators. */ | |
567 | for (w = di->bucket[par]; w; w = di->next_bucket[w]) | |
568 | { | |
569 | k = eval (di, w); | |
570 | if (di->key[k] < di->key[w]) | |
571 | di->dom[w] = k; | |
572 | else | |
573 | di->dom[w] = par; | |
574 | } | |
575 | /* We don't need to cleanup next_bucket[]. */ | |
576 | di->bucket[par] = 0; | |
577 | v--; | |
578 | } | |
579 | ||
a1f300c0 | 580 | /* Explicitly define the dominators. */ |
f8032688 MM |
581 | di->dom[1] = 0; |
582 | for (v = 2; v <= di->nodes; v++) | |
583 | if (di->dom[v] != di->key[v]) | |
584 | di->dom[v] = di->dom[di->dom[v]]; | |
585 | } | |
586 | ||
d47cc544 SB |
587 | /* Assign dfs numbers starting from NUM to NODE and its sons. */ |
588 | ||
589 | static void | |
590 | assign_dfs_numbers (struct et_node *node, int *num) | |
591 | { | |
592 | struct et_node *son; | |
593 | ||
594 | node->dfs_num_in = (*num)++; | |
595 | ||
596 | if (node->son) | |
597 | { | |
598 | assign_dfs_numbers (node->son, num); | |
599 | for (son = node->son->right; son != node->son; son = son->right) | |
6de9cd9a | 600 | assign_dfs_numbers (son, num); |
d47cc544 | 601 | } |
f8032688 | 602 | |
d47cc544 SB |
603 | node->dfs_num_out = (*num)++; |
604 | } | |
f8032688 | 605 | |
5d3cc252 | 606 | /* Compute the data necessary for fast resolving of dominator queries in a |
d47cc544 | 607 | static dominator tree. */ |
f8032688 | 608 | |
d47cc544 SB |
609 | static void |
610 | compute_dom_fast_query (enum cdi_direction dir) | |
611 | { | |
612 | int num = 0; | |
613 | basic_block bb; | |
2b28c07a | 614 | unsigned int dir_index = dom_convert_dir_to_idx (dir); |
d47cc544 | 615 | |
fce22de5 | 616 | gcc_assert (dom_info_available_p (dir)); |
d47cc544 | 617 | |
2b28c07a | 618 | if (dom_computed[dir_index] == DOM_OK) |
d47cc544 SB |
619 | return; |
620 | ||
621 | FOR_ALL_BB (bb) | |
622 | { | |
2b28c07a JC |
623 | if (!bb->dom[dir_index]->father) |
624 | assign_dfs_numbers (bb->dom[dir_index], &num); | |
d47cc544 SB |
625 | } |
626 | ||
2b28c07a | 627 | dom_computed[dir_index] = DOM_OK; |
d47cc544 SB |
628 | } |
629 | ||
630 | /* The main entry point into this module. DIR is set depending on whether | |
631 | we want to compute dominators or postdominators. */ | |
632 | ||
633 | void | |
634 | calculate_dominance_info (enum cdi_direction dir) | |
f8032688 MM |
635 | { |
636 | struct dom_info di; | |
355be0dc | 637 | basic_block b; |
2b28c07a JC |
638 | unsigned int dir_index = dom_convert_dir_to_idx (dir); |
639 | bool reverse = (dir == CDI_POST_DOMINATORS) ? true : false; | |
355be0dc | 640 | |
2b28c07a | 641 | if (dom_computed[dir_index] == DOM_OK) |
d47cc544 | 642 | return; |
355be0dc | 643 | |
74c96e0c | 644 | timevar_push (TV_DOMINANCE); |
fce22de5 | 645 | if (!dom_info_available_p (dir)) |
d47cc544 | 646 | { |
2b28c07a | 647 | gcc_assert (!n_bbs_in_dom_tree[dir_index]); |
f8032688 | 648 | |
d47cc544 SB |
649 | FOR_ALL_BB (b) |
650 | { | |
2b28c07a | 651 | b->dom[dir_index] = et_new_tree (b); |
d47cc544 | 652 | } |
2b28c07a | 653 | n_bbs_in_dom_tree[dir_index] = n_basic_blocks; |
f8032688 | 654 | |
26e0e410 | 655 | init_dom_info (&di, dir); |
2b28c07a JC |
656 | calc_dfs_tree (&di, reverse); |
657 | calc_idoms (&di, reverse); | |
355be0dc | 658 | |
d47cc544 SB |
659 | FOR_EACH_BB (b) |
660 | { | |
661 | TBB d = di.dom[di.dfs_order[b->index]]; | |
662 | ||
663 | if (di.dfs_to_bb[d]) | |
2b28c07a | 664 | et_set_father (b->dom[dir_index], di.dfs_to_bb[d]->dom[dir_index]); |
d47cc544 | 665 | } |
e0082a72 | 666 | |
d47cc544 | 667 | free_dom_info (&di); |
2b28c07a | 668 | dom_computed[dir_index] = DOM_NO_FAST_QUERY; |
355be0dc JH |
669 | } |
670 | ||
d47cc544 | 671 | compute_dom_fast_query (dir); |
74c96e0c ZD |
672 | |
673 | timevar_pop (TV_DOMINANCE); | |
355be0dc JH |
674 | } |
675 | ||
d47cc544 | 676 | /* Free dominance information for direction DIR. */ |
355be0dc | 677 | void |
d47cc544 | 678 | free_dominance_info (enum cdi_direction dir) |
355be0dc JH |
679 | { |
680 | basic_block bb; | |
2b28c07a | 681 | unsigned int dir_index = dom_convert_dir_to_idx (dir); |
355be0dc | 682 | |
fce22de5 | 683 | if (!dom_info_available_p (dir)) |
d47cc544 SB |
684 | return; |
685 | ||
686 | FOR_ALL_BB (bb) | |
687 | { | |
2b28c07a JC |
688 | et_free_tree_force (bb->dom[dir_index]); |
689 | bb->dom[dir_index] = NULL; | |
d47cc544 | 690 | } |
5a6ccafd | 691 | et_free_pools (); |
d47cc544 | 692 | |
2b28c07a | 693 | n_bbs_in_dom_tree[dir_index] = 0; |
6de9cd9a | 694 | |
2b28c07a | 695 | dom_computed[dir_index] = DOM_NONE; |
355be0dc JH |
696 | } |
697 | ||
698 | /* Return the immediate dominator of basic block BB. */ | |
699 | basic_block | |
d47cc544 | 700 | get_immediate_dominator (enum cdi_direction dir, basic_block bb) |
355be0dc | 701 | { |
2b28c07a JC |
702 | unsigned int dir_index = dom_convert_dir_to_idx (dir); |
703 | struct et_node *node = bb->dom[dir_index]; | |
d47cc544 | 704 | |
2b28c07a | 705 | gcc_assert (dom_computed[dir_index]); |
d47cc544 SB |
706 | |
707 | if (!node->father) | |
708 | return NULL; | |
709 | ||
6de9cd9a | 710 | return node->father->data; |
355be0dc JH |
711 | } |
712 | ||
713 | /* Set the immediate dominator of the block possibly removing | |
714 | existing edge. NULL can be used to remove any edge. */ | |
715 | inline void | |
d47cc544 SB |
716 | set_immediate_dominator (enum cdi_direction dir, basic_block bb, |
717 | basic_block dominated_by) | |
355be0dc | 718 | { |
2b28c07a JC |
719 | unsigned int dir_index = dom_convert_dir_to_idx (dir); |
720 | struct et_node *node = bb->dom[dir_index]; | |
721 | ||
722 | gcc_assert (dom_computed[dir_index]); | |
355be0dc | 723 | |
d47cc544 | 724 | if (node->father) |
355be0dc | 725 | { |
d47cc544 | 726 | if (node->father->data == dominated_by) |
6de9cd9a | 727 | return; |
d47cc544 | 728 | et_split (node); |
355be0dc | 729 | } |
d47cc544 SB |
730 | |
731 | if (dominated_by) | |
2b28c07a | 732 | et_set_father (node, dominated_by->dom[dir_index]); |
d47cc544 | 733 | |
2b28c07a JC |
734 | if (dom_computed[dir_index] == DOM_OK) |
735 | dom_computed[dir_index] = DOM_NO_FAST_QUERY; | |
355be0dc JH |
736 | } |
737 | ||
5d3cc252 | 738 | /* Store all basic blocks immediately dominated by BB into BBS and return |
d47cc544 | 739 | their number. */ |
355be0dc | 740 | int |
d47cc544 | 741 | get_dominated_by (enum cdi_direction dir, basic_block bb, basic_block **bbs) |
355be0dc | 742 | { |
2b28c07a | 743 | unsigned int dir_index = dom_convert_dir_to_idx (dir); |
d47cc544 | 744 | int n; |
2b28c07a JC |
745 | struct et_node *node = bb->dom[dir_index], *son = node->son, *ason; |
746 | ||
747 | gcc_assert (dom_computed[dir_index]); | |
d47cc544 SB |
748 | |
749 | if (!son) | |
750 | { | |
751 | *bbs = NULL; | |
752 | return 0; | |
753 | } | |
754 | ||
755 | for (ason = son->right, n = 1; ason != son; ason = ason->right) | |
756 | n++; | |
757 | ||
5ed6ace5 | 758 | *bbs = XNEWVEC (basic_block, n); |
d47cc544 SB |
759 | (*bbs)[0] = son->data; |
760 | for (ason = son->right, n = 1; ason != son; ason = ason->right) | |
761 | (*bbs)[n++] = ason->data; | |
355be0dc | 762 | |
355be0dc JH |
763 | return n; |
764 | } | |
765 | ||
42759f1e ZD |
766 | /* Find all basic blocks that are immediately dominated (in direction DIR) |
767 | by some block between N_REGION ones stored in REGION, except for blocks | |
768 | in the REGION itself. The found blocks are stored to DOMS and their number | |
769 | is returned. */ | |
770 | ||
771 | unsigned | |
772 | get_dominated_by_region (enum cdi_direction dir, basic_block *region, | |
773 | unsigned n_region, basic_block *doms) | |
774 | { | |
775 | unsigned n_doms = 0, i; | |
776 | basic_block dom; | |
777 | ||
778 | for (i = 0; i < n_region; i++) | |
6580ee77 | 779 | region[i]->flags |= BB_DUPLICATED; |
42759f1e ZD |
780 | for (i = 0; i < n_region; i++) |
781 | for (dom = first_dom_son (dir, region[i]); | |
782 | dom; | |
783 | dom = next_dom_son (dir, dom)) | |
6580ee77 | 784 | if (!(dom->flags & BB_DUPLICATED)) |
42759f1e ZD |
785 | doms[n_doms++] = dom; |
786 | for (i = 0; i < n_region; i++) | |
6580ee77 | 787 | region[i]->flags &= ~BB_DUPLICATED; |
42759f1e ZD |
788 | |
789 | return n_doms; | |
790 | } | |
791 | ||
355be0dc JH |
792 | /* Redirect all edges pointing to BB to TO. */ |
793 | void | |
d47cc544 SB |
794 | redirect_immediate_dominators (enum cdi_direction dir, basic_block bb, |
795 | basic_block to) | |
355be0dc | 796 | { |
2b28c07a JC |
797 | unsigned int dir_index = dom_convert_dir_to_idx (dir); |
798 | struct et_node *bb_node, *to_node, *son; | |
799 | ||
800 | bb_node = bb->dom[dir_index]; | |
801 | to_node = to->dom[dir_index]; | |
d47cc544 | 802 | |
2b28c07a | 803 | gcc_assert (dom_computed[dir_index]); |
355be0dc | 804 | |
d47cc544 SB |
805 | if (!bb_node->son) |
806 | return; | |
807 | ||
808 | while (bb_node->son) | |
355be0dc | 809 | { |
d47cc544 SB |
810 | son = bb_node->son; |
811 | ||
812 | et_split (son); | |
813 | et_set_father (son, to_node); | |
355be0dc | 814 | } |
d47cc544 | 815 | |
2b28c07a JC |
816 | if (dom_computed[dir_index] == DOM_OK) |
817 | dom_computed[dir_index] = DOM_NO_FAST_QUERY; | |
355be0dc JH |
818 | } |
819 | ||
820 | /* Find first basic block in the tree dominating both BB1 and BB2. */ | |
821 | basic_block | |
d47cc544 | 822 | nearest_common_dominator (enum cdi_direction dir, basic_block bb1, basic_block bb2) |
355be0dc | 823 | { |
2b28c07a JC |
824 | unsigned int dir_index = dom_convert_dir_to_idx (dir); |
825 | ||
826 | gcc_assert (dom_computed[dir_index]); | |
d47cc544 | 827 | |
355be0dc JH |
828 | if (!bb1) |
829 | return bb2; | |
830 | if (!bb2) | |
831 | return bb1; | |
d47cc544 | 832 | |
2b28c07a | 833 | return et_nca (bb1->dom[dir_index], bb2->dom[dir_index])->data; |
355be0dc JH |
834 | } |
835 | ||
0bca51f0 DN |
836 | |
837 | /* Find the nearest common dominator for the basic blocks in BLOCKS, | |
838 | using dominance direction DIR. */ | |
839 | ||
840 | basic_block | |
841 | nearest_common_dominator_for_set (enum cdi_direction dir, bitmap blocks) | |
842 | { | |
843 | unsigned i, first; | |
844 | bitmap_iterator bi; | |
845 | basic_block dom; | |
846 | ||
847 | first = bitmap_first_set_bit (blocks); | |
848 | dom = BASIC_BLOCK (first); | |
849 | EXECUTE_IF_SET_IN_BITMAP (blocks, 0, i, bi) | |
850 | if (dom != BASIC_BLOCK (i)) | |
851 | dom = nearest_common_dominator (dir, dom, BASIC_BLOCK (i)); | |
852 | ||
853 | return dom; | |
854 | } | |
855 | ||
b629276a DB |
856 | /* Given a dominator tree, we can determine whether one thing |
857 | dominates another in constant time by using two DFS numbers: | |
858 | ||
859 | 1. The number for when we visit a node on the way down the tree | |
860 | 2. The number for when we visit a node on the way back up the tree | |
861 | ||
862 | You can view these as bounds for the range of dfs numbers the | |
863 | nodes in the subtree of the dominator tree rooted at that node | |
864 | will contain. | |
865 | ||
866 | The dominator tree is always a simple acyclic tree, so there are | |
867 | only three possible relations two nodes in the dominator tree have | |
868 | to each other: | |
869 | ||
870 | 1. Node A is above Node B (and thus, Node A dominates node B) | |
871 | ||
872 | A | |
873 | | | |
874 | C | |
875 | / \ | |
876 | B D | |
877 | ||
878 | ||
879 | In the above case, DFS_Number_In of A will be <= DFS_Number_In of | |
880 | B, and DFS_Number_Out of A will be >= DFS_Number_Out of B. This is | |
881 | because we must hit A in the dominator tree *before* B on the walk | |
882 | down, and we will hit A *after* B on the walk back up | |
883 | ||
d8701f02 | 884 | 2. Node A is below node B (and thus, node B dominates node A) |
b629276a DB |
885 | |
886 | ||
887 | B | |
888 | | | |
889 | A | |
890 | / \ | |
891 | C D | |
892 | ||
893 | In the above case, DFS_Number_In of A will be >= DFS_Number_In of | |
894 | B, and DFS_Number_Out of A will be <= DFS_Number_Out of B. | |
895 | ||
896 | This is because we must hit A in the dominator tree *after* B on | |
897 | the walk down, and we will hit A *before* B on the walk back up | |
898 | ||
899 | 3. Node A and B are siblings (and thus, neither dominates the other) | |
900 | ||
901 | C | |
902 | | | |
903 | D | |
904 | / \ | |
905 | A B | |
906 | ||
907 | In the above case, DFS_Number_In of A will *always* be <= | |
908 | DFS_Number_In of B, and DFS_Number_Out of A will *always* be <= | |
909 | DFS_Number_Out of B. This is because we will always finish the dfs | |
910 | walk of one of the subtrees before the other, and thus, the dfs | |
911 | numbers for one subtree can't intersect with the range of dfs | |
912 | numbers for the other subtree. If you swap A and B's position in | |
913 | the dominator tree, the comparison changes direction, but the point | |
914 | is that both comparisons will always go the same way if there is no | |
915 | dominance relationship. | |
916 | ||
917 | Thus, it is sufficient to write | |
918 | ||
919 | A_Dominates_B (node A, node B) | |
920 | { | |
921 | return DFS_Number_In(A) <= DFS_Number_In(B) | |
922 | && DFS_Number_Out (A) >= DFS_Number_Out(B); | |
923 | } | |
924 | ||
925 | A_Dominated_by_B (node A, node B) | |
926 | { | |
927 | return DFS_Number_In(A) >= DFS_Number_In(A) | |
928 | && DFS_Number_Out (A) <= DFS_Number_Out(B); | |
929 | } */ | |
0bca51f0 | 930 | |
355be0dc JH |
931 | /* Return TRUE in case BB1 is dominated by BB2. */ |
932 | bool | |
d47cc544 | 933 | dominated_by_p (enum cdi_direction dir, basic_block bb1, basic_block bb2) |
6de9cd9a | 934 | { |
2b28c07a JC |
935 | unsigned int dir_index = dom_convert_dir_to_idx (dir); |
936 | struct et_node *n1 = bb1->dom[dir_index], *n2 = bb2->dom[dir_index]; | |
937 | ||
938 | gcc_assert (dom_computed[dir_index]); | |
d47cc544 | 939 | |
2b28c07a | 940 | if (dom_computed[dir_index] == DOM_OK) |
d47cc544 | 941 | return (n1->dfs_num_in >= n2->dfs_num_in |
6de9cd9a | 942 | && n1->dfs_num_out <= n2->dfs_num_out); |
d47cc544 SB |
943 | |
944 | return et_below (n1, n2); | |
355be0dc JH |
945 | } |
946 | ||
f074ff6c ZD |
947 | /* Returns the entry dfs number for basic block BB, in the direction DIR. */ |
948 | ||
949 | unsigned | |
950 | bb_dom_dfs_in (enum cdi_direction dir, basic_block bb) | |
951 | { | |
2b28c07a JC |
952 | unsigned int dir_index = dom_convert_dir_to_idx (dir); |
953 | struct et_node *n = bb->dom[dir_index]; | |
f074ff6c | 954 | |
2b28c07a | 955 | gcc_assert (dom_computed[dir_index] == DOM_OK); |
f074ff6c ZD |
956 | return n->dfs_num_in; |
957 | } | |
958 | ||
959 | /* Returns the exit dfs number for basic block BB, in the direction DIR. */ | |
960 | ||
961 | unsigned | |
962 | bb_dom_dfs_out (enum cdi_direction dir, basic_block bb) | |
963 | { | |
2b28c07a JC |
964 | unsigned int dir_index = dom_convert_dir_to_idx (dir); |
965 | struct et_node *n = bb->dom[dir_index]; | |
f074ff6c | 966 | |
2b28c07a | 967 | gcc_assert (dom_computed[dir_index] == DOM_OK); |
f074ff6c ZD |
968 | return n->dfs_num_out; |
969 | } | |
970 | ||
355be0dc JH |
971 | /* Verify invariants of dominator structure. */ |
972 | void | |
d47cc544 | 973 | verify_dominators (enum cdi_direction dir) |
355be0dc JH |
974 | { |
975 | int err = 0; | |
976 | basic_block bb; | |
977 | ||
fce22de5 | 978 | gcc_assert (dom_info_available_p (dir)); |
d47cc544 | 979 | |
355be0dc JH |
980 | FOR_EACH_BB (bb) |
981 | { | |
982 | basic_block dom_bb; | |
df485d80 | 983 | basic_block imm_bb; |
355be0dc | 984 | |
d47cc544 | 985 | dom_bb = recount_dominator (dir, bb); |
df485d80 FCE |
986 | imm_bb = get_immediate_dominator (dir, bb); |
987 | if (dom_bb != imm_bb) | |
f8032688 | 988 | { |
df485d80 FCE |
989 | if ((dom_bb == NULL) || (imm_bb == NULL)) |
990 | error ("dominator of %d status unknown", bb->index); | |
08fb229e FCE |
991 | else |
992 | error ("dominator of %d should be %d, not %d", | |
df485d80 | 993 | bb->index, dom_bb->index, imm_bb->index); |
355be0dc JH |
994 | err = 1; |
995 | } | |
996 | } | |
e7bd94cc | 997 | |
fce22de5 | 998 | if (dir == CDI_DOMINATORS) |
e7bd94cc ZD |
999 | { |
1000 | FOR_EACH_BB (bb) | |
1001 | { | |
1002 | if (!dominated_by_p (dir, bb, ENTRY_BLOCK_PTR)) | |
1003 | { | |
1004 | error ("ENTRY does not dominate bb %d", bb->index); | |
1005 | err = 1; | |
1006 | } | |
1007 | } | |
1008 | } | |
1009 | ||
ced3f397 | 1010 | gcc_assert (!err); |
355be0dc JH |
1011 | } |
1012 | ||
738ed977 ZD |
1013 | /* Determine immediate dominator (or postdominator, according to DIR) of BB, |
1014 | assuming that dominators of other blocks are correct. We also use it to | |
1015 | recompute the dominators in a restricted area, by iterating it until it | |
71cc389b | 1016 | reaches a fixed point. */ |
738ed977 | 1017 | |
355be0dc | 1018 | basic_block |
d47cc544 | 1019 | recount_dominator (enum cdi_direction dir, basic_block bb) |
355be0dc | 1020 | { |
2b28c07a | 1021 | unsigned int dir_index = dom_convert_dir_to_idx (dir); |
738ed977 ZD |
1022 | basic_block dom_bb = NULL; |
1023 | edge e; | |
628f6a4e | 1024 | edge_iterator ei; |
355be0dc | 1025 | |
2b28c07a | 1026 | gcc_assert (dom_computed[dir_index]); |
d47cc544 | 1027 | |
738ed977 ZD |
1028 | if (dir == CDI_DOMINATORS) |
1029 | { | |
628f6a4e | 1030 | FOR_EACH_EDGE (e, ei, bb->preds) |
738ed977 | 1031 | { |
e7bd94cc ZD |
1032 | /* Ignore the predecessors that either are not reachable from |
1033 | the entry block, or whose dominator was not determined yet. */ | |
1034 | if (!dominated_by_p (dir, e->src, ENTRY_BLOCK_PTR)) | |
1035 | continue; | |
1036 | ||
738ed977 ZD |
1037 | if (!dominated_by_p (dir, e->src, bb)) |
1038 | dom_bb = nearest_common_dominator (dir, dom_bb, e->src); | |
1039 | } | |
1040 | } | |
1041 | else | |
1042 | { | |
628f6a4e | 1043 | FOR_EACH_EDGE (e, ei, bb->succs) |
738ed977 ZD |
1044 | { |
1045 | if (!dominated_by_p (dir, e->dest, bb)) | |
1046 | dom_bb = nearest_common_dominator (dir, dom_bb, e->dest); | |
1047 | } | |
1048 | } | |
f8032688 | 1049 | |
738ed977 | 1050 | return dom_bb; |
355be0dc JH |
1051 | } |
1052 | ||
1053 | /* Iteratively recount dominators of BBS. The change is supposed to be local | |
1054 | and not to grow further. */ | |
1055 | void | |
d47cc544 | 1056 | iterate_fix_dominators (enum cdi_direction dir, basic_block *bbs, int n) |
355be0dc | 1057 | { |
2b28c07a | 1058 | unsigned int dir_index = dom_convert_dir_to_idx (dir); |
355be0dc JH |
1059 | int i, changed = 1; |
1060 | basic_block old_dom, new_dom; | |
1061 | ||
2b28c07a | 1062 | gcc_assert (dom_computed[dir_index]); |
d47cc544 | 1063 | |
e7bd94cc ZD |
1064 | for (i = 0; i < n; i++) |
1065 | set_immediate_dominator (dir, bbs[i], NULL); | |
1066 | ||
355be0dc JH |
1067 | while (changed) |
1068 | { | |
1069 | changed = 0; | |
1070 | for (i = 0; i < n; i++) | |
1071 | { | |
d47cc544 SB |
1072 | old_dom = get_immediate_dominator (dir, bbs[i]); |
1073 | new_dom = recount_dominator (dir, bbs[i]); | |
355be0dc JH |
1074 | if (old_dom != new_dom) |
1075 | { | |
1076 | changed = 1; | |
d47cc544 | 1077 | set_immediate_dominator (dir, bbs[i], new_dom); |
355be0dc | 1078 | } |
f8032688 MM |
1079 | } |
1080 | } | |
e7bd94cc ZD |
1081 | |
1082 | for (i = 0; i < n; i++) | |
ced3f397 | 1083 | gcc_assert (get_immediate_dominator (dir, bbs[i])); |
355be0dc | 1084 | } |
f8032688 | 1085 | |
355be0dc | 1086 | void |
d47cc544 | 1087 | add_to_dominance_info (enum cdi_direction dir, basic_block bb) |
355be0dc | 1088 | { |
2b28c07a JC |
1089 | unsigned int dir_index = dom_convert_dir_to_idx (dir); |
1090 | ||
1091 | gcc_assert (dom_computed[dir_index]); | |
1092 | gcc_assert (!bb->dom[dir_index]); | |
d47cc544 | 1093 | |
2b28c07a | 1094 | n_bbs_in_dom_tree[dir_index]++; |
6de9cd9a | 1095 | |
2b28c07a | 1096 | bb->dom[dir_index] = et_new_tree (bb); |
d47cc544 | 1097 | |
2b28c07a JC |
1098 | if (dom_computed[dir_index] == DOM_OK) |
1099 | dom_computed[dir_index] = DOM_NO_FAST_QUERY; | |
355be0dc JH |
1100 | } |
1101 | ||
1102 | void | |
d47cc544 SB |
1103 | delete_from_dominance_info (enum cdi_direction dir, basic_block bb) |
1104 | { | |
2b28c07a | 1105 | unsigned int dir_index = dom_convert_dir_to_idx (dir); |
d47cc544 | 1106 | |
2b28c07a | 1107 | gcc_assert (dom_computed[dir_index]); |
d47cc544 | 1108 | |
2b28c07a JC |
1109 | et_free_tree (bb->dom[dir_index]); |
1110 | bb->dom[dir_index] = NULL; | |
1111 | n_bbs_in_dom_tree[dir_index]--; | |
1112 | ||
1113 | if (dom_computed[dir_index] == DOM_OK) | |
1114 | dom_computed[dir_index] = DOM_NO_FAST_QUERY; | |
d47cc544 SB |
1115 | } |
1116 | ||
1117 | /* Returns the first son of BB in the dominator or postdominator tree | |
1118 | as determined by DIR. */ | |
1119 | ||
1120 | basic_block | |
1121 | first_dom_son (enum cdi_direction dir, basic_block bb) | |
355be0dc | 1122 | { |
2b28c07a JC |
1123 | unsigned int dir_index = dom_convert_dir_to_idx (dir); |
1124 | struct et_node *son = bb->dom[dir_index]->son; | |
d47cc544 SB |
1125 | |
1126 | return son ? son->data : NULL; | |
1127 | } | |
1128 | ||
1129 | /* Returns the next dominance son after BB in the dominator or postdominator | |
1130 | tree as determined by DIR, or NULL if it was the last one. */ | |
1131 | ||
1132 | basic_block | |
1133 | next_dom_son (enum cdi_direction dir, basic_block bb) | |
1134 | { | |
2b28c07a JC |
1135 | unsigned int dir_index = dom_convert_dir_to_idx (dir); |
1136 | struct et_node *next = bb->dom[dir_index]->right; | |
d47cc544 SB |
1137 | |
1138 | return next->father->son == next ? NULL : next->data; | |
355be0dc JH |
1139 | } |
1140 | ||
2b28c07a JC |
1141 | /* Return dominance availability for dominance info DIR. */ |
1142 | ||
1143 | enum dom_state | |
1144 | dom_info_state (enum cdi_direction dir) | |
1145 | { | |
1146 | unsigned int dir_index = dom_convert_dir_to_idx (dir); | |
1147 | ||
1148 | return dom_computed[dir_index]; | |
1149 | } | |
1150 | ||
1151 | /* Set the dominance availability for dominance info DIR to NEW_STATE. */ | |
1152 | ||
1153 | void | |
1154 | set_dom_info_availability (enum cdi_direction dir, enum dom_state new_state) | |
1155 | { | |
1156 | unsigned int dir_index = dom_convert_dir_to_idx (dir); | |
1157 | ||
1158 | dom_computed[dir_index] = new_state; | |
1159 | } | |
1160 | ||
fce22de5 ZD |
1161 | /* Returns true if dominance information for direction DIR is available. */ |
1162 | ||
1163 | bool | |
1164 | dom_info_available_p (enum cdi_direction dir) | |
1165 | { | |
2b28c07a JC |
1166 | unsigned int dir_index = dom_convert_dir_to_idx (dir); |
1167 | ||
1168 | return dom_computed[dir_index] != DOM_NONE; | |
fce22de5 ZD |
1169 | } |
1170 | ||
355be0dc | 1171 | void |
d47cc544 | 1172 | debug_dominance_info (enum cdi_direction dir) |
355be0dc JH |
1173 | { |
1174 | basic_block bb, bb2; | |
1175 | FOR_EACH_BB (bb) | |
d47cc544 | 1176 | if ((bb2 = get_immediate_dominator (dir, bb))) |
355be0dc | 1177 | fprintf (stderr, "%i %i\n", bb->index, bb2->index); |
f8032688 | 1178 | } |