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4794f989 | 1 | /* Calculate (post)dominators in slightly super-linear time. |
7cf0dbf3 | 2 | Copyright (C) 2000, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010 |
3 | Free Software Foundation, Inc. | |
4794f989 | 4 | Contributed by Michael Matz (matz@ifh.de). |
1eefe280 | 5 | |
f12b58b3 | 6 | This file is part of GCC. |
1eefe280 | 7 | |
f12b58b3 | 8 | GCC is free software; you can redistribute it and/or modify it |
9 | under the terms of the GNU General Public License as published by | |
8c4c00c1 | 10 | the Free Software Foundation; either version 3, or (at your option) |
4794f989 | 11 | any later version. |
12 | ||
f12b58b3 | 13 | GCC is distributed in the hope that it will be useful, but WITHOUT |
14 | ANY WARRANTY; without even the implied warranty of MERCHANTABILITY | |
15 | or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public | |
16 | License for more details. | |
4794f989 | 17 | |
18 | You should have received a copy of the GNU General Public License | |
8c4c00c1 | 19 | along with GCC; see the file COPYING3. If not see |
20 | <http://www.gnu.org/licenses/>. */ | |
4794f989 | 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 | ||
3fb1e43b | 31 | The algorithm computes this dominator tree implicitly by computing for |
4794f989 | 32 | each block its immediate dominator. We use tree balancing and path |
20833d12 | 33 | compression, so it's the O(e*a(e,v)) variant, where a(e,v) is the very |
4794f989 | 34 | slowly growing functional inverse of the Ackerman function. */ |
35 | ||
36 | #include "config.h" | |
37 | #include "system.h" | |
805e22b2 | 38 | #include "coretypes.h" |
39 | #include "tm.h" | |
4794f989 | 40 | #include "rtl.h" |
41 | #include "hard-reg-set.h" | |
42fe97ed | 42 | #include "obstack.h" |
4794f989 | 43 | #include "basic-block.h" |
0b205f4c | 44 | #include "diagnostic-core.h" |
89d75d78 | 45 | #include "et-forest.h" |
a6e6c89a | 46 | #include "timevar.h" |
3f9439d7 | 47 | #include "vecprim.h" |
48 | #include "pointer-set.h" | |
49 | #include "graphds.h" | |
0f71a633 | 50 | #include "bitmap.h" |
4794f989 | 51 | |
4794f989 | 52 | /* We name our nodes with integers, beginning with 1. Zero is reserved for |
53 | 'undefined' or 'end of list'. The name of each node is given by the dfs | |
54 | number of the corresponding basic block. Please note, that we include the | |
55 | artificial ENTRY_BLOCK (or EXIT_BLOCK in the post-dom case) in our lists to | |
4d2e5d52 | 56 | support multiple entry points. Its dfs number is of course 1. */ |
4794f989 | 57 | |
58 | /* Type of Basic Block aka. TBB */ | |
59 | typedef unsigned int TBB; | |
60 | ||
61 | /* We work in a poor-mans object oriented fashion, and carry an instance of | |
62 | this structure through all our 'methods'. It holds various arrays | |
63 | reflecting the (sub)structure of the flowgraph. Most of them are of type | |
64 | TBB and are also indexed by TBB. */ | |
65 | ||
66 | struct dom_info | |
67 | { | |
68 | /* The parent of a node in the DFS tree. */ | |
69 | TBB *dfs_parent; | |
70 | /* For a node x key[x] is roughly the node nearest to the root from which | |
71 | exists a way to x only over nodes behind x. Such a node is also called | |
72 | semidominator. */ | |
73 | TBB *key; | |
74 | /* The value in path_min[x] is the node y on the path from x to the root of | |
75 | the tree x is in with the smallest key[y]. */ | |
76 | TBB *path_min; | |
77 | /* bucket[x] points to the first node of the set of nodes having x as key. */ | |
78 | TBB *bucket; | |
79 | /* And next_bucket[x] points to the next node. */ | |
80 | TBB *next_bucket; | |
81 | /* After the algorithm is done, dom[x] contains the immediate dominator | |
82 | of x. */ | |
83 | TBB *dom; | |
84 | ||
85 | /* The following few fields implement the structures needed for disjoint | |
86 | sets. */ | |
f0b5f617 | 87 | /* set_chain[x] is the next node on the path from x to the representative |
4794f989 | 88 | of the set containing x. If set_chain[x]==0 then x is a root. */ |
89 | TBB *set_chain; | |
90 | /* set_size[x] is the number of elements in the set named by x. */ | |
91 | unsigned int *set_size; | |
92 | /* set_child[x] is used for balancing the tree representing a set. It can | |
93 | be understood as the next sibling of x. */ | |
94 | TBB *set_child; | |
95 | ||
96 | /* If b is the number of a basic block (BB->index), dfs_order[b] is the | |
97 | number of that node in DFS order counted from 1. This is an index | |
98 | into most of the other arrays in this structure. */ | |
99 | TBB *dfs_order; | |
edc2a478 | 100 | /* If x is the DFS-index of a node which corresponds with a basic block, |
4794f989 | 101 | dfs_to_bb[x] is that basic block. Note, that in our structure there are |
102 | more nodes that basic blocks, so only dfs_to_bb[dfs_order[bb->index]]==bb | |
103 | is true for every basic block bb, but not the opposite. */ | |
104 | basic_block *dfs_to_bb; | |
105 | ||
8828f7b7 | 106 | /* This is the next free DFS number when creating the DFS tree. */ |
4794f989 | 107 | unsigned int dfsnum; |
108 | /* The number of nodes in the DFS tree (==dfsnum-1). */ | |
109 | unsigned int nodes; | |
8828f7b7 | 110 | |
111 | /* Blocks with bits set here have a fake edge to EXIT. These are used | |
112 | to turn a DFS forest into a proper tree. */ | |
113 | bitmap fake_exit_edge; | |
4794f989 | 114 | }; |
115 | ||
8828f7b7 | 116 | static void init_dom_info (struct dom_info *, enum cdi_direction); |
8ec3a57b | 117 | static void free_dom_info (struct dom_info *); |
50b08d37 | 118 | static void calc_dfs_tree_nonrec (struct dom_info *, basic_block, bool); |
119 | static void calc_dfs_tree (struct dom_info *, bool); | |
8ec3a57b | 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); | |
50b08d37 | 123 | static void calc_idoms (struct dom_info *, bool); |
0051c76a | 124 | void debug_dominance_info (enum cdi_direction); |
0bffc570 | 125 | void debug_dominance_tree (enum cdi_direction, basic_block); |
4794f989 | 126 | |
127 | /* Helper macro for allocating and initializing an array, | |
128 | for aesthetic reasons. */ | |
129 | #define init_ar(var, type, num, content) \ | |
1eefe280 | 130 | do \ |
131 | { \ | |
132 | unsigned int i = 1; /* Catch content == i. */ \ | |
133 | if (! (content)) \ | |
4c36ffe6 | 134 | (var) = XCNEWVEC (type, num); \ |
1eefe280 | 135 | else \ |
136 | { \ | |
4c36ffe6 | 137 | (var) = XNEWVEC (type, (num)); \ |
1eefe280 | 138 | for (i = 0; i < num; i++) \ |
139 | (var)[i] = (content); \ | |
140 | } \ | |
141 | } \ | |
142 | while (0) | |
4794f989 | 143 | |
144 | /* Allocate all needed memory in a pessimistic fashion (so we round up). | |
457275b6 | 145 | This initializes the contents of DI, which already must be allocated. */ |
4794f989 | 146 | |
147 | static void | |
8828f7b7 | 148 | init_dom_info (struct dom_info *di, enum cdi_direction dir) |
4794f989 | 149 | { |
3072d30e | 150 | /* We need memory for n_basic_blocks nodes. */ |
4d2e5d52 | 151 | unsigned int num = n_basic_blocks; |
4794f989 | 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 | ||
f20183e6 | 164 | init_ar (di->dfs_order, TBB, (unsigned int) last_basic_block + 1, 0); |
4794f989 | 165 | init_ar (di->dfs_to_bb, basic_block, num, 0); |
166 | ||
167 | di->dfsnum = 1; | |
168 | di->nodes = 0; | |
8828f7b7 | 169 | |
50b08d37 | 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 | } | |
4794f989 | 182 | } |
183 | ||
184 | #undef init_ar | |
185 | ||
50b08d37 | 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 | { | |
1cface39 | 194 | gcc_checking_assert (dir == CDI_DOMINATORS || dir == CDI_POST_DOMINATORS); |
50b08d37 | 195 | return dir - 1; |
196 | } | |
197 | ||
4794f989 | 198 | /* Free all allocated memory in DI, but not DI itself. */ |
199 | ||
200 | static void | |
8ec3a57b | 201 | free_dom_info (struct dom_info *di) |
4794f989 | 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); | |
27335ffd | 214 | BITMAP_FREE (di->fake_exit_edge); |
4794f989 | 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 | |
50b08d37 | 224 | calc_dfs_tree_nonrec (struct dom_info *di, basic_block bb, bool reverse) |
4794f989 | 225 | { |
4794f989 | 226 | /* We call this _only_ if bb is not already visited. */ |
227 | edge e; | |
228 | TBB child_i, my_i = 0; | |
cd665a06 | 229 | edge_iterator *stack; |
230 | edge_iterator ei, einext; | |
4794f989 | 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 | ||
4c36ffe6 | 238 | stack = XNEWVEC (edge_iterator, n_basic_blocks + 1); |
4794f989 | 239 | sp = 0; |
240 | ||
241 | /* Initialize our border blocks, and the first edge. */ | |
242 | if (reverse) | |
243 | { | |
cd665a06 | 244 | ei = ei_start (bb->preds); |
4794f989 | 245 | en_block = EXIT_BLOCK_PTR; |
246 | ex_block = ENTRY_BLOCK_PTR; | |
247 | } | |
248 | else | |
249 | { | |
cd665a06 | 250 | ei = ei_start (bb->succs); |
4794f989 | 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. */ | |
cd665a06 | 262 | while (!ei_end_p (ei)) |
4794f989 | 263 | { |
cd665a06 | 264 | e = ei_edge (ei); |
4794f989 | 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. */ | |
b3d6de89 | 275 | if (bn == ex_block || di->dfs_order[bn->index]) |
4794f989 | 276 | { |
cd665a06 | 277 | ei_next (&ei); |
4794f989 | 278 | continue; |
279 | } | |
280 | bb = e->dest; | |
cd665a06 | 281 | einext = ei_start (bn->preds); |
4794f989 | 282 | } |
283 | else | |
284 | { | |
285 | bn = e->dest; | |
b3d6de89 | 286 | if (bn == ex_block || di->dfs_order[bn->index]) |
4794f989 | 287 | { |
cd665a06 | 288 | ei_next (&ei); |
4794f989 | 289 | continue; |
290 | } | |
291 | bb = e->src; | |
cd665a06 | 292 | einext = ei_start (bn->succs); |
4794f989 | 293 | } |
294 | ||
7bd4f6b6 | 295 | gcc_assert (bn != en_block); |
4794f989 | 296 | |
297 | /* Fill the DFS tree info calculatable _before_ recursing. */ | |
298 | if (bb != en_block) | |
b3d6de89 | 299 | my_i = di->dfs_order[bb->index]; |
4794f989 | 300 | else |
f20183e6 | 301 | my_i = di->dfs_order[last_basic_block]; |
b3d6de89 | 302 | child_i = di->dfs_order[bn->index] = di->dfsnum++; |
4794f989 | 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. */ | |
cd665a06 | 307 | stack[sp++] = ei; |
308 | ei = einext; | |
4794f989 | 309 | } |
310 | ||
311 | if (!sp) | |
312 | break; | |
cd665a06 | 313 | ei = stack[--sp]; |
4794f989 | 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. */ | |
cd665a06 | 324 | ei_next (&ei); |
4794f989 | 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 | |
50b08d37 | 335 | calc_dfs_tree (struct dom_info *di, bool reverse) |
4794f989 | 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; | |
f20183e6 | 339 | di->dfs_order[last_basic_block] = di->dfsnum; |
4794f989 | 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 | |
8828f7b7 | 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 | ||
4c26117a | 357 | basic_block b; |
8828f7b7 | 358 | bool saw_unconnected = false; |
359 | ||
4c26117a | 360 | FOR_EACH_BB_REVERSE (b) |
4794f989 | 361 | { |
cd665a06 | 362 | if (EDGE_COUNT (b->succs) > 0) |
8828f7b7 | 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); | |
b3d6de89 | 369 | di->dfs_order[b->index] = di->dfsnum; |
4794f989 | 370 | di->dfs_to_bb[di->dfsnum] = b; |
8828f7b7 | 371 | di->dfs_parent[di->dfsnum] = di->dfs_order[last_basic_block]; |
4794f989 | 372 | di->dfsnum++; |
373 | calc_dfs_tree_nonrec (di, b, reverse); | |
374 | } | |
8828f7b7 | 375 | |
376 | if (saw_unconnected) | |
377 | { | |
378 | FOR_EACH_BB_REVERSE (b) | |
379 | { | |
9ccd9ece | 380 | basic_block b2; |
8828f7b7 | 381 | if (di->dfs_order[b->index]) |
382 | continue; | |
9ccd9ece | 383 | b2 = dfs_find_deadend (b); |
384 | gcc_checking_assert (di->dfs_order[b2->index] == 0); | |
385 | bitmap_set_bit (di->fake_exit_edge, b2->index); | |
386 | di->dfs_order[b2->index] = di->dfsnum; | |
387 | di->dfs_to_bb[di->dfsnum] = b2; | |
8828f7b7 | 388 | di->dfs_parent[di->dfsnum] = di->dfs_order[last_basic_block]; |
389 | di->dfsnum++; | |
9ccd9ece | 390 | calc_dfs_tree_nonrec (di, b2, reverse); |
391 | gcc_checking_assert (di->dfs_order[b->index]); | |
8828f7b7 | 392 | } |
393 | } | |
4794f989 | 394 | } |
395 | ||
396 | di->nodes = di->dfsnum - 1; | |
397 | ||
4d2e5d52 | 398 | /* This aborts e.g. when there is _no_ path from ENTRY to EXIT at all. */ |
399 | gcc_assert (di->nodes == (unsigned int) n_basic_blocks - 1); | |
4794f989 | 400 | } |
401 | ||
402 | /* Compress the path from V to the root of its set and update path_min at the | |
403 | same time. After compress(di, V) set_chain[V] is the root of the set V is | |
404 | in and path_min[V] is the node with the smallest key[] value on the path | |
405 | from V to that root. */ | |
406 | ||
407 | static void | |
8ec3a57b | 408 | compress (struct dom_info *di, TBB v) |
4794f989 | 409 | { |
410 | /* Btw. It's not worth to unrecurse compress() as the depth is usually not | |
411 | greater than 5 even for huge graphs (I've not seen call depth > 4). | |
412 | Also performance wise compress() ranges _far_ behind eval(). */ | |
413 | TBB parent = di->set_chain[v]; | |
414 | if (di->set_chain[parent]) | |
415 | { | |
416 | compress (di, parent); | |
417 | if (di->key[di->path_min[parent]] < di->key[di->path_min[v]]) | |
418 | di->path_min[v] = di->path_min[parent]; | |
419 | di->set_chain[v] = di->set_chain[parent]; | |
420 | } | |
421 | } | |
422 | ||
423 | /* Compress the path from V to the set root of V if needed (when the root has | |
424 | changed since the last call). Returns the node with the smallest key[] | |
425 | value on the path from V to the root. */ | |
426 | ||
427 | static inline TBB | |
8ec3a57b | 428 | eval (struct dom_info *di, TBB v) |
4794f989 | 429 | { |
f0b5f617 | 430 | /* The representative of the set V is in, also called root (as the set |
4794f989 | 431 | representation is a tree). */ |
432 | TBB rep = di->set_chain[v]; | |
433 | ||
434 | /* V itself is the root. */ | |
435 | if (!rep) | |
436 | return di->path_min[v]; | |
437 | ||
438 | /* Compress only if necessary. */ | |
439 | if (di->set_chain[rep]) | |
440 | { | |
441 | compress (di, v); | |
442 | rep = di->set_chain[v]; | |
443 | } | |
444 | ||
445 | if (di->key[di->path_min[rep]] >= di->key[di->path_min[v]]) | |
446 | return di->path_min[v]; | |
447 | else | |
448 | return di->path_min[rep]; | |
449 | } | |
450 | ||
451 | /* This essentially merges the two sets of V and W, giving a single set with | |
452 | the new root V. The internal representation of these disjoint sets is a | |
453 | balanced tree. Currently link(V,W) is only used with V being the parent | |
454 | of W. */ | |
455 | ||
456 | static void | |
8ec3a57b | 457 | link_roots (struct dom_info *di, TBB v, TBB w) |
4794f989 | 458 | { |
459 | TBB s = w; | |
460 | ||
461 | /* Rebalance the tree. */ | |
462 | while (di->key[di->path_min[w]] < di->key[di->path_min[di->set_child[s]]]) | |
463 | { | |
464 | if (di->set_size[s] + di->set_size[di->set_child[di->set_child[s]]] | |
465 | >= 2 * di->set_size[di->set_child[s]]) | |
466 | { | |
467 | di->set_chain[di->set_child[s]] = s; | |
468 | di->set_child[s] = di->set_child[di->set_child[s]]; | |
469 | } | |
470 | else | |
471 | { | |
472 | di->set_size[di->set_child[s]] = di->set_size[s]; | |
473 | s = di->set_chain[s] = di->set_child[s]; | |
474 | } | |
475 | } | |
476 | ||
477 | di->path_min[s] = di->path_min[w]; | |
478 | di->set_size[v] += di->set_size[w]; | |
479 | if (di->set_size[v] < 2 * di->set_size[w]) | |
480 | { | |
481 | TBB tmp = s; | |
482 | s = di->set_child[v]; | |
483 | di->set_child[v] = tmp; | |
484 | } | |
485 | ||
486 | /* Merge all subtrees. */ | |
487 | while (s) | |
488 | { | |
489 | di->set_chain[s] = v; | |
490 | s = di->set_child[s]; | |
491 | } | |
492 | } | |
493 | ||
494 | /* This calculates the immediate dominators (or post-dominators if REVERSE is | |
495 | true). DI is our working structure and should hold the DFS forest. | |
496 | On return the immediate dominator to node V is in di->dom[V]. */ | |
497 | ||
498 | static void | |
50b08d37 | 499 | calc_idoms (struct dom_info *di, bool reverse) |
4794f989 | 500 | { |
501 | TBB v, w, k, par; | |
502 | basic_block en_block; | |
cd665a06 | 503 | edge_iterator ei, einext; |
504 | ||
4794f989 | 505 | if (reverse) |
506 | en_block = EXIT_BLOCK_PTR; | |
507 | else | |
508 | en_block = ENTRY_BLOCK_PTR; | |
509 | ||
510 | /* Go backwards in DFS order, to first look at the leafs. */ | |
511 | v = di->nodes; | |
512 | while (v > 1) | |
513 | { | |
514 | basic_block bb = di->dfs_to_bb[v]; | |
cd665a06 | 515 | edge e; |
4794f989 | 516 | |
517 | par = di->dfs_parent[v]; | |
518 | k = v; | |
cd665a06 | 519 | |
520 | ei = (reverse) ? ei_start (bb->succs) : ei_start (bb->preds); | |
521 | ||
4794f989 | 522 | if (reverse) |
8828f7b7 | 523 | { |
8828f7b7 | 524 | /* If this block has a fake edge to exit, process that first. */ |
525 | if (bitmap_bit_p (di->fake_exit_edge, bb->index)) | |
526 | { | |
cd665a06 | 527 | einext = ei; |
528 | einext.index = 0; | |
8828f7b7 | 529 | goto do_fake_exit_edge; |
530 | } | |
531 | } | |
4794f989 | 532 | |
533 | /* Search all direct predecessors for the smallest node with a path | |
534 | to them. That way we have the smallest node with also a path to | |
535 | us only over nodes behind us. In effect we search for our | |
536 | semidominator. */ | |
cd665a06 | 537 | while (!ei_end_p (ei)) |
4794f989 | 538 | { |
539 | TBB k1; | |
540 | basic_block b; | |
541 | ||
cd665a06 | 542 | e = ei_edge (ei); |
543 | b = (reverse) ? e->dest : e->src; | |
544 | einext = ei; | |
545 | ei_next (&einext); | |
546 | ||
4794f989 | 547 | if (b == en_block) |
8828f7b7 | 548 | { |
549 | do_fake_exit_edge: | |
550 | k1 = di->dfs_order[last_basic_block]; | |
551 | } | |
4794f989 | 552 | else |
b3d6de89 | 553 | k1 = di->dfs_order[b->index]; |
4794f989 | 554 | |
555 | /* Call eval() only if really needed. If k1 is above V in DFS tree, | |
556 | then we know, that eval(k1) == k1 and key[k1] == k1. */ | |
557 | if (k1 > v) | |
558 | k1 = di->key[eval (di, k1)]; | |
559 | if (k1 < k) | |
560 | k = k1; | |
cd665a06 | 561 | |
562 | ei = einext; | |
4794f989 | 563 | } |
564 | ||
565 | di->key[v] = k; | |
566 | link_roots (di, par, v); | |
567 | di->next_bucket[v] = di->bucket[k]; | |
568 | di->bucket[k] = v; | |
569 | ||
570 | /* Transform semidominators into dominators. */ | |
571 | for (w = di->bucket[par]; w; w = di->next_bucket[w]) | |
572 | { | |
573 | k = eval (di, w); | |
574 | if (di->key[k] < di->key[w]) | |
575 | di->dom[w] = k; | |
576 | else | |
577 | di->dom[w] = par; | |
578 | } | |
579 | /* We don't need to cleanup next_bucket[]. */ | |
580 | di->bucket[par] = 0; | |
581 | v--; | |
582 | } | |
583 | ||
3fb1e43b | 584 | /* Explicitly define the dominators. */ |
4794f989 | 585 | di->dom[1] = 0; |
586 | for (v = 2; v <= di->nodes; v++) | |
587 | if (di->dom[v] != di->key[v]) | |
588 | di->dom[v] = di->dom[di->dom[v]]; | |
589 | } | |
590 | ||
0051c76a | 591 | /* Assign dfs numbers starting from NUM to NODE and its sons. */ |
592 | ||
593 | static void | |
594 | assign_dfs_numbers (struct et_node *node, int *num) | |
595 | { | |
596 | struct et_node *son; | |
597 | ||
598 | node->dfs_num_in = (*num)++; | |
599 | ||
600 | if (node->son) | |
601 | { | |
602 | assign_dfs_numbers (node->son, num); | |
603 | for (son = node->son->right; son != node->son; son = son->right) | |
4ee9c684 | 604 | assign_dfs_numbers (son, num); |
0051c76a | 605 | } |
4794f989 | 606 | |
0051c76a | 607 | node->dfs_num_out = (*num)++; |
608 | } | |
4794f989 | 609 | |
d632b59a | 610 | /* Compute the data necessary for fast resolving of dominator queries in a |
0051c76a | 611 | static dominator tree. */ |
4794f989 | 612 | |
0051c76a | 613 | static void |
614 | compute_dom_fast_query (enum cdi_direction dir) | |
615 | { | |
616 | int num = 0; | |
617 | basic_block bb; | |
50b08d37 | 618 | unsigned int dir_index = dom_convert_dir_to_idx (dir); |
0051c76a | 619 | |
1cface39 | 620 | gcc_checking_assert (dom_info_available_p (dir)); |
0051c76a | 621 | |
50b08d37 | 622 | if (dom_computed[dir_index] == DOM_OK) |
0051c76a | 623 | return; |
624 | ||
625 | FOR_ALL_BB (bb) | |
626 | { | |
50b08d37 | 627 | if (!bb->dom[dir_index]->father) |
628 | assign_dfs_numbers (bb->dom[dir_index], &num); | |
0051c76a | 629 | } |
630 | ||
50b08d37 | 631 | dom_computed[dir_index] = DOM_OK; |
0051c76a | 632 | } |
633 | ||
634 | /* The main entry point into this module. DIR is set depending on whether | |
635 | we want to compute dominators or postdominators. */ | |
636 | ||
637 | void | |
638 | calculate_dominance_info (enum cdi_direction dir) | |
4794f989 | 639 | { |
640 | struct dom_info di; | |
89d75d78 | 641 | basic_block b; |
50b08d37 | 642 | unsigned int dir_index = dom_convert_dir_to_idx (dir); |
643 | bool reverse = (dir == CDI_POST_DOMINATORS) ? true : false; | |
89d75d78 | 644 | |
50b08d37 | 645 | if (dom_computed[dir_index] == DOM_OK) |
0051c76a | 646 | return; |
89d75d78 | 647 | |
a6e6c89a | 648 | timevar_push (TV_DOMINANCE); |
6b9d2769 | 649 | if (!dom_info_available_p (dir)) |
0051c76a | 650 | { |
50b08d37 | 651 | gcc_assert (!n_bbs_in_dom_tree[dir_index]); |
4794f989 | 652 | |
0051c76a | 653 | FOR_ALL_BB (b) |
654 | { | |
50b08d37 | 655 | b->dom[dir_index] = et_new_tree (b); |
0051c76a | 656 | } |
50b08d37 | 657 | n_bbs_in_dom_tree[dir_index] = n_basic_blocks; |
4794f989 | 658 | |
8828f7b7 | 659 | init_dom_info (&di, dir); |
50b08d37 | 660 | calc_dfs_tree (&di, reverse); |
661 | calc_idoms (&di, reverse); | |
89d75d78 | 662 | |
0051c76a | 663 | FOR_EACH_BB (b) |
664 | { | |
665 | TBB d = di.dom[di.dfs_order[b->index]]; | |
666 | ||
667 | if (di.dfs_to_bb[d]) | |
50b08d37 | 668 | et_set_father (b->dom[dir_index], di.dfs_to_bb[d]->dom[dir_index]); |
0051c76a | 669 | } |
4c26117a | 670 | |
0051c76a | 671 | free_dom_info (&di); |
50b08d37 | 672 | dom_computed[dir_index] = DOM_NO_FAST_QUERY; |
89d75d78 | 673 | } |
674 | ||
0051c76a | 675 | compute_dom_fast_query (dir); |
a6e6c89a | 676 | |
677 | timevar_pop (TV_DOMINANCE); | |
89d75d78 | 678 | } |
679 | ||
0051c76a | 680 | /* Free dominance information for direction DIR. */ |
89d75d78 | 681 | void |
0051c76a | 682 | free_dominance_info (enum cdi_direction dir) |
89d75d78 | 683 | { |
684 | basic_block bb; | |
50b08d37 | 685 | unsigned int dir_index = dom_convert_dir_to_idx (dir); |
89d75d78 | 686 | |
6b9d2769 | 687 | if (!dom_info_available_p (dir)) |
0051c76a | 688 | return; |
689 | ||
690 | FOR_ALL_BB (bb) | |
691 | { | |
50b08d37 | 692 | et_free_tree_force (bb->dom[dir_index]); |
693 | bb->dom[dir_index] = NULL; | |
0051c76a | 694 | } |
0a06d4f0 | 695 | et_free_pools (); |
0051c76a | 696 | |
50b08d37 | 697 | n_bbs_in_dom_tree[dir_index] = 0; |
4ee9c684 | 698 | |
50b08d37 | 699 | dom_computed[dir_index] = DOM_NONE; |
89d75d78 | 700 | } |
701 | ||
702 | /* Return the immediate dominator of basic block BB. */ | |
703 | basic_block | |
0051c76a | 704 | get_immediate_dominator (enum cdi_direction dir, basic_block bb) |
89d75d78 | 705 | { |
50b08d37 | 706 | unsigned int dir_index = dom_convert_dir_to_idx (dir); |
707 | struct et_node *node = bb->dom[dir_index]; | |
0051c76a | 708 | |
1cface39 | 709 | gcc_checking_assert (dom_computed[dir_index]); |
0051c76a | 710 | |
711 | if (!node->father) | |
712 | return NULL; | |
713 | ||
364c0c59 | 714 | return (basic_block) node->father->data; |
89d75d78 | 715 | } |
716 | ||
717 | /* Set the immediate dominator of the block possibly removing | |
718 | existing edge. NULL can be used to remove any edge. */ | |
878edb92 | 719 | void |
0051c76a | 720 | set_immediate_dominator (enum cdi_direction dir, basic_block bb, |
721 | basic_block dominated_by) | |
89d75d78 | 722 | { |
50b08d37 | 723 | unsigned int dir_index = dom_convert_dir_to_idx (dir); |
724 | struct et_node *node = bb->dom[dir_index]; | |
48e1416a | 725 | |
1cface39 | 726 | gcc_checking_assert (dom_computed[dir_index]); |
89d75d78 | 727 | |
0051c76a | 728 | if (node->father) |
89d75d78 | 729 | { |
0051c76a | 730 | if (node->father->data == dominated_by) |
4ee9c684 | 731 | return; |
0051c76a | 732 | et_split (node); |
89d75d78 | 733 | } |
0051c76a | 734 | |
735 | if (dominated_by) | |
50b08d37 | 736 | et_set_father (node, dominated_by->dom[dir_index]); |
0051c76a | 737 | |
50b08d37 | 738 | if (dom_computed[dir_index] == DOM_OK) |
739 | dom_computed[dir_index] = DOM_NO_FAST_QUERY; | |
89d75d78 | 740 | } |
741 | ||
3f9439d7 | 742 | /* Returns the list of basic blocks immediately dominated by BB, in the |
743 | direction DIR. */ | |
744 | VEC (basic_block, heap) * | |
745 | get_dominated_by (enum cdi_direction dir, basic_block bb) | |
89d75d78 | 746 | { |
3f9439d7 | 747 | unsigned int dir_index = dom_convert_dir_to_idx (dir); |
50b08d37 | 748 | struct et_node *node = bb->dom[dir_index], *son = node->son, *ason; |
3f9439d7 | 749 | VEC (basic_block, heap) *bbs = NULL; |
750 | ||
1cface39 | 751 | gcc_checking_assert (dom_computed[dir_index]); |
0051c76a | 752 | |
753 | if (!son) | |
3f9439d7 | 754 | return NULL; |
0051c76a | 755 | |
364c0c59 | 756 | VEC_safe_push (basic_block, heap, bbs, (basic_block) son->data); |
01703575 | 757 | for (ason = son->right; ason != son; ason = ason->right) |
364c0c59 | 758 | VEC_safe_push (basic_block, heap, bbs, (basic_block) ason->data); |
89d75d78 | 759 | |
3f9439d7 | 760 | return bbs; |
89d75d78 | 761 | } |
762 | ||
3f9439d7 | 763 | /* Returns the list of basic blocks that are immediately dominated (in |
764 | direction DIR) by some block between N_REGION ones stored in REGION, | |
765 | except for blocks in the REGION itself. */ | |
48e1416a | 766 | |
3f9439d7 | 767 | VEC (basic_block, heap) * |
d8b5b4fe | 768 | get_dominated_by_region (enum cdi_direction dir, basic_block *region, |
3f9439d7 | 769 | unsigned n_region) |
d8b5b4fe | 770 | { |
3f9439d7 | 771 | unsigned i; |
d8b5b4fe | 772 | basic_block dom; |
3f9439d7 | 773 | VEC (basic_block, heap) *doms = NULL; |
d8b5b4fe | 774 | |
775 | for (i = 0; i < n_region; i++) | |
01020a5f | 776 | region[i]->flags |= BB_DUPLICATED; |
d8b5b4fe | 777 | for (i = 0; i < n_region; i++) |
778 | for (dom = first_dom_son (dir, region[i]); | |
779 | dom; | |
780 | dom = next_dom_son (dir, dom)) | |
01020a5f | 781 | if (!(dom->flags & BB_DUPLICATED)) |
3f9439d7 | 782 | VEC_safe_push (basic_block, heap, doms, dom); |
d8b5b4fe | 783 | for (i = 0; i < n_region; i++) |
01020a5f | 784 | region[i]->flags &= ~BB_DUPLICATED; |
d8b5b4fe | 785 | |
3f9439d7 | 786 | return doms; |
d8b5b4fe | 787 | } |
788 | ||
59f3ea59 | 789 | /* Returns the list of basic blocks including BB dominated by BB, in the |
c0939130 | 790 | direction DIR up to DEPTH in the dominator tree. The DEPTH of zero will |
791 | produce a vector containing all dominated blocks. The vector will be sorted | |
792 | in preorder. */ | |
59f3ea59 | 793 | |
794 | VEC (basic_block, heap) * | |
c0939130 | 795 | get_dominated_to_depth (enum cdi_direction dir, basic_block bb, int depth) |
59f3ea59 | 796 | { |
797 | VEC(basic_block, heap) *bbs = NULL; | |
798 | unsigned i; | |
c0939130 | 799 | unsigned next_level_start; |
59f3ea59 | 800 | |
801 | i = 0; | |
802 | VEC_safe_push (basic_block, heap, bbs, bb); | |
c0939130 | 803 | next_level_start = 1; /* = VEC_length (basic_block, bbs); */ |
59f3ea59 | 804 | |
805 | do | |
806 | { | |
807 | basic_block son; | |
808 | ||
809 | bb = VEC_index (basic_block, bbs, i++); | |
810 | for (son = first_dom_son (dir, bb); | |
811 | son; | |
812 | son = next_dom_son (dir, son)) | |
813 | VEC_safe_push (basic_block, heap, bbs, son); | |
c0939130 | 814 | |
815 | if (i == next_level_start && --depth) | |
816 | next_level_start = VEC_length (basic_block, bbs); | |
59f3ea59 | 817 | } |
c0939130 | 818 | while (i < next_level_start); |
59f3ea59 | 819 | |
820 | return bbs; | |
821 | } | |
822 | ||
c0939130 | 823 | /* Returns the list of basic blocks including BB dominated by BB, in the |
824 | direction DIR. The vector will be sorted in preorder. */ | |
825 | ||
826 | VEC (basic_block, heap) * | |
827 | get_all_dominated_blocks (enum cdi_direction dir, basic_block bb) | |
828 | { | |
829 | return get_dominated_to_depth (dir, bb, 0); | |
830 | } | |
831 | ||
89d75d78 | 832 | /* Redirect all edges pointing to BB to TO. */ |
833 | void | |
0051c76a | 834 | redirect_immediate_dominators (enum cdi_direction dir, basic_block bb, |
835 | basic_block to) | |
89d75d78 | 836 | { |
50b08d37 | 837 | unsigned int dir_index = dom_convert_dir_to_idx (dir); |
838 | struct et_node *bb_node, *to_node, *son; | |
48e1416a | 839 | |
50b08d37 | 840 | bb_node = bb->dom[dir_index]; |
841 | to_node = to->dom[dir_index]; | |
0051c76a | 842 | |
1cface39 | 843 | gcc_checking_assert (dom_computed[dir_index]); |
89d75d78 | 844 | |
0051c76a | 845 | if (!bb_node->son) |
846 | return; | |
847 | ||
848 | while (bb_node->son) | |
89d75d78 | 849 | { |
0051c76a | 850 | son = bb_node->son; |
851 | ||
852 | et_split (son); | |
853 | et_set_father (son, to_node); | |
89d75d78 | 854 | } |
0051c76a | 855 | |
50b08d37 | 856 | if (dom_computed[dir_index] == DOM_OK) |
857 | dom_computed[dir_index] = DOM_NO_FAST_QUERY; | |
89d75d78 | 858 | } |
859 | ||
860 | /* Find first basic block in the tree dominating both BB1 and BB2. */ | |
861 | basic_block | |
0051c76a | 862 | nearest_common_dominator (enum cdi_direction dir, basic_block bb1, basic_block bb2) |
89d75d78 | 863 | { |
50b08d37 | 864 | unsigned int dir_index = dom_convert_dir_to_idx (dir); |
865 | ||
1cface39 | 866 | gcc_checking_assert (dom_computed[dir_index]); |
0051c76a | 867 | |
89d75d78 | 868 | if (!bb1) |
869 | return bb2; | |
870 | if (!bb2) | |
871 | return bb1; | |
0051c76a | 872 | |
364c0c59 | 873 | return (basic_block) et_nca (bb1->dom[dir_index], bb2->dom[dir_index])->data; |
89d75d78 | 874 | } |
875 | ||
88dbf20f | 876 | |
877 | /* Find the nearest common dominator for the basic blocks in BLOCKS, | |
878 | using dominance direction DIR. */ | |
879 | ||
880 | basic_block | |
881 | nearest_common_dominator_for_set (enum cdi_direction dir, bitmap blocks) | |
882 | { | |
883 | unsigned i, first; | |
884 | bitmap_iterator bi; | |
885 | basic_block dom; | |
48e1416a | 886 | |
88dbf20f | 887 | first = bitmap_first_set_bit (blocks); |
888 | dom = BASIC_BLOCK (first); | |
889 | EXECUTE_IF_SET_IN_BITMAP (blocks, 0, i, bi) | |
890 | if (dom != BASIC_BLOCK (i)) | |
891 | dom = nearest_common_dominator (dir, dom, BASIC_BLOCK (i)); | |
892 | ||
893 | return dom; | |
894 | } | |
895 | ||
6a11f5f6 | 896 | /* Given a dominator tree, we can determine whether one thing |
897 | dominates another in constant time by using two DFS numbers: | |
898 | ||
899 | 1. The number for when we visit a node on the way down the tree | |
900 | 2. The number for when we visit a node on the way back up the tree | |
901 | ||
902 | You can view these as bounds for the range of dfs numbers the | |
903 | nodes in the subtree of the dominator tree rooted at that node | |
904 | will contain. | |
48e1416a | 905 | |
6a11f5f6 | 906 | The dominator tree is always a simple acyclic tree, so there are |
907 | only three possible relations two nodes in the dominator tree have | |
908 | to each other: | |
48e1416a | 909 | |
6a11f5f6 | 910 | 1. Node A is above Node B (and thus, Node A dominates node B) |
911 | ||
912 | A | |
913 | | | |
914 | C | |
915 | / \ | |
916 | B D | |
917 | ||
918 | ||
919 | In the above case, DFS_Number_In of A will be <= DFS_Number_In of | |
920 | B, and DFS_Number_Out of A will be >= DFS_Number_Out of B. This is | |
921 | because we must hit A in the dominator tree *before* B on the walk | |
922 | down, and we will hit A *after* B on the walk back up | |
48e1416a | 923 | |
e055ef98 | 924 | 2. Node A is below node B (and thus, node B dominates node A) |
48e1416a | 925 | |
926 | ||
6a11f5f6 | 927 | B |
928 | | | |
929 | A | |
930 | / \ | |
931 | C D | |
932 | ||
933 | In the above case, DFS_Number_In of A will be >= DFS_Number_In of | |
934 | B, and DFS_Number_Out of A will be <= DFS_Number_Out of B. | |
48e1416a | 935 | |
6a11f5f6 | 936 | This is because we must hit A in the dominator tree *after* B on |
937 | the walk down, and we will hit A *before* B on the walk back up | |
48e1416a | 938 | |
6a11f5f6 | 939 | 3. Node A and B are siblings (and thus, neither dominates the other) |
940 | ||
941 | C | |
942 | | | |
943 | D | |
944 | / \ | |
945 | A B | |
946 | ||
947 | In the above case, DFS_Number_In of A will *always* be <= | |
948 | DFS_Number_In of B, and DFS_Number_Out of A will *always* be <= | |
949 | DFS_Number_Out of B. This is because we will always finish the dfs | |
950 | walk of one of the subtrees before the other, and thus, the dfs | |
951 | numbers for one subtree can't intersect with the range of dfs | |
952 | numbers for the other subtree. If you swap A and B's position in | |
953 | the dominator tree, the comparison changes direction, but the point | |
954 | is that both comparisons will always go the same way if there is no | |
955 | dominance relationship. | |
956 | ||
957 | Thus, it is sufficient to write | |
958 | ||
959 | A_Dominates_B (node A, node B) | |
960 | { | |
48e1416a | 961 | return DFS_Number_In(A) <= DFS_Number_In(B) |
6a11f5f6 | 962 | && DFS_Number_Out (A) >= DFS_Number_Out(B); |
963 | } | |
964 | ||
965 | A_Dominated_by_B (node A, node B) | |
966 | { | |
967 | return DFS_Number_In(A) >= DFS_Number_In(A) | |
968 | && DFS_Number_Out (A) <= DFS_Number_Out(B); | |
969 | } */ | |
88dbf20f | 970 | |
89d75d78 | 971 | /* Return TRUE in case BB1 is dominated by BB2. */ |
972 | bool | |
7ecb5bb2 | 973 | dominated_by_p (enum cdi_direction dir, const_basic_block bb1, const_basic_block bb2) |
48e1416a | 974 | { |
50b08d37 | 975 | unsigned int dir_index = dom_convert_dir_to_idx (dir); |
976 | struct et_node *n1 = bb1->dom[dir_index], *n2 = bb2->dom[dir_index]; | |
48e1416a | 977 | |
1cface39 | 978 | gcc_checking_assert (dom_computed[dir_index]); |
0051c76a | 979 | |
50b08d37 | 980 | if (dom_computed[dir_index] == DOM_OK) |
0051c76a | 981 | return (n1->dfs_num_in >= n2->dfs_num_in |
4ee9c684 | 982 | && n1->dfs_num_out <= n2->dfs_num_out); |
0051c76a | 983 | |
984 | return et_below (n1, n2); | |
89d75d78 | 985 | } |
986 | ||
f50cf978 | 987 | /* Returns the entry dfs number for basic block BB, in the direction DIR. */ |
988 | ||
989 | unsigned | |
990 | bb_dom_dfs_in (enum cdi_direction dir, basic_block bb) | |
991 | { | |
50b08d37 | 992 | unsigned int dir_index = dom_convert_dir_to_idx (dir); |
993 | struct et_node *n = bb->dom[dir_index]; | |
f50cf978 | 994 | |
1cface39 | 995 | gcc_checking_assert (dom_computed[dir_index] == DOM_OK); |
f50cf978 | 996 | return n->dfs_num_in; |
997 | } | |
998 | ||
999 | /* Returns the exit dfs number for basic block BB, in the direction DIR. */ | |
1000 | ||
1001 | unsigned | |
1002 | bb_dom_dfs_out (enum cdi_direction dir, basic_block bb) | |
1003 | { | |
50b08d37 | 1004 | unsigned int dir_index = dom_convert_dir_to_idx (dir); |
1005 | struct et_node *n = bb->dom[dir_index]; | |
f50cf978 | 1006 | |
1cface39 | 1007 | gcc_checking_assert (dom_computed[dir_index] == DOM_OK); |
f50cf978 | 1008 | return n->dfs_num_out; |
1009 | } | |
1010 | ||
89d75d78 | 1011 | /* Verify invariants of dominator structure. */ |
4b987fac | 1012 | DEBUG_FUNCTION void |
0051c76a | 1013 | verify_dominators (enum cdi_direction dir) |
89d75d78 | 1014 | { |
1015 | int err = 0; | |
0bffc570 | 1016 | basic_block bb, imm_bb, imm_bb_correct; |
1017 | struct dom_info di; | |
1018 | bool reverse = (dir == CDI_POST_DOMINATORS) ? true : false; | |
89d75d78 | 1019 | |
6b9d2769 | 1020 | gcc_assert (dom_info_available_p (dir)); |
0051c76a | 1021 | |
0bffc570 | 1022 | init_dom_info (&di, dir); |
1023 | calc_dfs_tree (&di, reverse); | |
1024 | calc_idoms (&di, reverse); | |
1025 | ||
89d75d78 | 1026 | FOR_EACH_BB (bb) |
1027 | { | |
0bffc570 | 1028 | imm_bb = get_immediate_dominator (dir, bb); |
1029 | if (!imm_bb) | |
4794f989 | 1030 | { |
3f9439d7 | 1031 | error ("dominator of %d status unknown", bb->index); |
89d75d78 | 1032 | err = 1; |
1033 | } | |
3f9439d7 | 1034 | |
0bffc570 | 1035 | imm_bb_correct = di.dfs_to_bb[di.dom[di.dfs_order[bb->index]]]; |
1036 | if (imm_bb != imm_bb_correct) | |
e7f5d6c3 | 1037 | { |
3f9439d7 | 1038 | error ("dominator of %d should be %d, not %d", |
0bffc570 | 1039 | bb->index, imm_bb_correct->index, imm_bb->index); |
3f9439d7 | 1040 | err = 1; |
e7f5d6c3 | 1041 | } |
1042 | } | |
1043 | ||
0bffc570 | 1044 | free_dom_info (&di); |
7bd4f6b6 | 1045 | gcc_assert (!err); |
89d75d78 | 1046 | } |
1047 | ||
3745d6a0 | 1048 | /* Determine immediate dominator (or postdominator, according to DIR) of BB, |
1049 | assuming that dominators of other blocks are correct. We also use it to | |
1050 | recompute the dominators in a restricted area, by iterating it until it | |
5aedf60c | 1051 | reaches a fixed point. */ |
3745d6a0 | 1052 | |
89d75d78 | 1053 | basic_block |
3f9439d7 | 1054 | recompute_dominator (enum cdi_direction dir, basic_block bb) |
89d75d78 | 1055 | { |
50b08d37 | 1056 | unsigned int dir_index = dom_convert_dir_to_idx (dir); |
3745d6a0 | 1057 | basic_block dom_bb = NULL; |
1058 | edge e; | |
cd665a06 | 1059 | edge_iterator ei; |
89d75d78 | 1060 | |
1cface39 | 1061 | gcc_checking_assert (dom_computed[dir_index]); |
0051c76a | 1062 | |
3745d6a0 | 1063 | if (dir == CDI_DOMINATORS) |
1064 | { | |
cd665a06 | 1065 | FOR_EACH_EDGE (e, ei, bb->preds) |
3745d6a0 | 1066 | { |
1067 | if (!dominated_by_p (dir, e->src, bb)) | |
1068 | dom_bb = nearest_common_dominator (dir, dom_bb, e->src); | |
1069 | } | |
1070 | } | |
1071 | else | |
1072 | { | |
cd665a06 | 1073 | FOR_EACH_EDGE (e, ei, bb->succs) |
3745d6a0 | 1074 | { |
1075 | if (!dominated_by_p (dir, e->dest, bb)) | |
1076 | dom_bb = nearest_common_dominator (dir, dom_bb, e->dest); | |
1077 | } | |
1078 | } | |
4794f989 | 1079 | |
3745d6a0 | 1080 | return dom_bb; |
89d75d78 | 1081 | } |
1082 | ||
3f9439d7 | 1083 | /* Use simple heuristics (see iterate_fix_dominators) to determine dominators |
1084 | of BBS. We assume that all the immediate dominators except for those of the | |
1085 | blocks in BBS are correct. If CONSERVATIVE is true, we also assume that the | |
1086 | currently recorded immediate dominators of blocks in BBS really dominate the | |
1087 | blocks. The basic blocks for that we determine the dominator are removed | |
1088 | from BBS. */ | |
1089 | ||
1090 | static void | |
1091 | prune_bbs_to_update_dominators (VEC (basic_block, heap) *bbs, | |
1092 | bool conservative) | |
1093 | { | |
1094 | unsigned i; | |
1095 | bool single; | |
1096 | basic_block bb, dom = NULL; | |
1097 | edge_iterator ei; | |
1098 | edge e; | |
1099 | ||
1100 | for (i = 0; VEC_iterate (basic_block, bbs, i, bb);) | |
1101 | { | |
1102 | if (bb == ENTRY_BLOCK_PTR) | |
1103 | goto succeed; | |
1104 | ||
1105 | if (single_pred_p (bb)) | |
1106 | { | |
1107 | set_immediate_dominator (CDI_DOMINATORS, bb, single_pred (bb)); | |
1108 | goto succeed; | |
1109 | } | |
1110 | ||
1111 | if (!conservative) | |
1112 | goto fail; | |
1113 | ||
1114 | single = true; | |
1115 | dom = NULL; | |
1116 | FOR_EACH_EDGE (e, ei, bb->preds) | |
1117 | { | |
1118 | if (dominated_by_p (CDI_DOMINATORS, e->src, bb)) | |
1119 | continue; | |
1120 | ||
1121 | if (!dom) | |
1122 | dom = e->src; | |
1123 | else | |
1124 | { | |
1125 | single = false; | |
1126 | dom = nearest_common_dominator (CDI_DOMINATORS, dom, e->src); | |
1127 | } | |
1128 | } | |
1129 | ||
1130 | gcc_assert (dom != NULL); | |
1131 | if (single | |
1132 | || find_edge (dom, bb)) | |
1133 | { | |
1134 | set_immediate_dominator (CDI_DOMINATORS, bb, dom); | |
1135 | goto succeed; | |
1136 | } | |
1137 | ||
1138 | fail: | |
1139 | i++; | |
1140 | continue; | |
1141 | ||
1142 | succeed: | |
1143 | VEC_unordered_remove (basic_block, bbs, i); | |
1144 | } | |
1145 | } | |
1146 | ||
1147 | /* Returns root of the dominance tree in the direction DIR that contains | |
1148 | BB. */ | |
1149 | ||
1150 | static basic_block | |
1151 | root_of_dom_tree (enum cdi_direction dir, basic_block bb) | |
1152 | { | |
364c0c59 | 1153 | return (basic_block) et_root (bb->dom[dom_convert_dir_to_idx (dir)])->data; |
3f9439d7 | 1154 | } |
1155 | ||
1156 | /* See the comment in iterate_fix_dominators. Finds the immediate dominators | |
1157 | for the sons of Y, found using the SON and BROTHER arrays representing | |
1158 | the dominance tree of graph G. BBS maps the vertices of G to the basic | |
1159 | blocks. */ | |
1160 | ||
1161 | static void | |
1162 | determine_dominators_for_sons (struct graph *g, VEC (basic_block, heap) *bbs, | |
1163 | int y, int *son, int *brother) | |
1164 | { | |
1165 | bitmap gprime; | |
1166 | int i, a, nc; | |
1167 | VEC (int, heap) **sccs; | |
1168 | basic_block bb, dom, ybb; | |
1169 | unsigned si; | |
1170 | edge e; | |
1171 | edge_iterator ei; | |
1172 | ||
1173 | if (son[y] == -1) | |
1174 | return; | |
1175 | if (y == (int) VEC_length (basic_block, bbs)) | |
1176 | ybb = ENTRY_BLOCK_PTR; | |
1177 | else | |
1178 | ybb = VEC_index (basic_block, bbs, y); | |
1179 | ||
1180 | if (brother[son[y]] == -1) | |
1181 | { | |
1182 | /* Handle the common case Y has just one son specially. */ | |
1183 | bb = VEC_index (basic_block, bbs, son[y]); | |
1184 | set_immediate_dominator (CDI_DOMINATORS, bb, | |
1185 | recompute_dominator (CDI_DOMINATORS, bb)); | |
1186 | identify_vertices (g, y, son[y]); | |
1187 | return; | |
1188 | } | |
1189 | ||
1190 | gprime = BITMAP_ALLOC (NULL); | |
1191 | for (a = son[y]; a != -1; a = brother[a]) | |
1192 | bitmap_set_bit (gprime, a); | |
1193 | ||
1194 | nc = graphds_scc (g, gprime); | |
1195 | BITMAP_FREE (gprime); | |
1196 | ||
1197 | sccs = XCNEWVEC (VEC (int, heap) *, nc); | |
1198 | for (a = son[y]; a != -1; a = brother[a]) | |
1199 | VEC_safe_push (int, heap, sccs[g->vertices[a].component], a); | |
1200 | ||
1201 | for (i = nc - 1; i >= 0; i--) | |
1202 | { | |
1203 | dom = NULL; | |
48148244 | 1204 | FOR_EACH_VEC_ELT (int, sccs[i], si, a) |
3f9439d7 | 1205 | { |
1206 | bb = VEC_index (basic_block, bbs, a); | |
1207 | FOR_EACH_EDGE (e, ei, bb->preds) | |
1208 | { | |
1209 | if (root_of_dom_tree (CDI_DOMINATORS, e->src) != ybb) | |
1210 | continue; | |
1211 | ||
1212 | dom = nearest_common_dominator (CDI_DOMINATORS, dom, e->src); | |
1213 | } | |
1214 | } | |
1215 | ||
1216 | gcc_assert (dom != NULL); | |
48148244 | 1217 | FOR_EACH_VEC_ELT (int, sccs[i], si, a) |
3f9439d7 | 1218 | { |
1219 | bb = VEC_index (basic_block, bbs, a); | |
1220 | set_immediate_dominator (CDI_DOMINATORS, bb, dom); | |
1221 | } | |
1222 | } | |
1223 | ||
1224 | for (i = 0; i < nc; i++) | |
1225 | VEC_free (int, heap, sccs[i]); | |
1226 | free (sccs); | |
1227 | ||
1228 | for (a = son[y]; a != -1; a = brother[a]) | |
1229 | identify_vertices (g, y, a); | |
1230 | } | |
1231 | ||
1232 | /* Recompute dominance information for basic blocks in the set BBS. The | |
1233 | function assumes that the immediate dominators of all the other blocks | |
1234 | in CFG are correct, and that there are no unreachable blocks. | |
1235 | ||
1236 | If CONSERVATIVE is true, we additionally assume that all the ancestors of | |
1237 | a block of BBS in the current dominance tree dominate it. */ | |
1238 | ||
89d75d78 | 1239 | void |
3f9439d7 | 1240 | iterate_fix_dominators (enum cdi_direction dir, VEC (basic_block, heap) *bbs, |
1241 | bool conservative) | |
89d75d78 | 1242 | { |
3f9439d7 | 1243 | unsigned i; |
1244 | basic_block bb, dom; | |
1245 | struct graph *g; | |
1246 | int n, y; | |
1247 | size_t dom_i; | |
1248 | edge e; | |
1249 | edge_iterator ei; | |
1250 | struct pointer_map_t *map; | |
1251 | int *parent, *son, *brother; | |
50b08d37 | 1252 | unsigned int dir_index = dom_convert_dir_to_idx (dir); |
89d75d78 | 1253 | |
3f9439d7 | 1254 | /* We only support updating dominators. There are some problems with |
1255 | updating postdominators (need to add fake edges from infinite loops | |
1256 | and noreturn functions), and since we do not currently use | |
1257 | iterate_fix_dominators for postdominators, any attempt to handle these | |
1258 | problems would be unused, untested, and almost surely buggy. We keep | |
1259 | the DIR argument for consistency with the rest of the dominator analysis | |
1260 | interface. */ | |
1cface39 | 1261 | gcc_checking_assert (dir == CDI_DOMINATORS && dom_computed[dir_index]); |
0051c76a | 1262 | |
3f9439d7 | 1263 | /* The algorithm we use takes inspiration from the following papers, although |
1264 | the details are quite different from any of them: | |
1265 | ||
1266 | [1] G. Ramalingam, T. Reps, An Incremental Algorithm for Maintaining the | |
1267 | Dominator Tree of a Reducible Flowgraph | |
1268 | [2] V. C. Sreedhar, G. R. Gao, Y.-F. Lee: Incremental computation of | |
1269 | dominator trees | |
1270 | [3] K. D. Cooper, T. J. Harvey and K. Kennedy: A Simple, Fast Dominance | |
1271 | Algorithm | |
1272 | ||
1273 | First, we use the following heuristics to decrease the size of the BBS | |
1274 | set: | |
1275 | a) if BB has a single predecessor, then its immediate dominator is this | |
1276 | predecessor | |
1277 | additionally, if CONSERVATIVE is true: | |
1278 | b) if all the predecessors of BB except for one (X) are dominated by BB, | |
1279 | then X is the immediate dominator of BB | |
1280 | c) if the nearest common ancestor of the predecessors of BB is X and | |
1281 | X -> BB is an edge in CFG, then X is the immediate dominator of BB | |
1282 | ||
1283 | Then, we need to establish the dominance relation among the basic blocks | |
1284 | in BBS. We split the dominance tree by removing the immediate dominator | |
bef304b8 | 1285 | edges from BBS, creating a forest F. We form a graph G whose vertices |
3f9439d7 | 1286 | are BBS and ENTRY and X -> Y is an edge of G if there exists an edge |
bef304b8 | 1287 | X' -> Y in CFG such that X' belongs to the tree of the dominance forest |
3f9439d7 | 1288 | whose root is X. We then determine dominance tree of G. Note that |
1289 | for X, Y in BBS, X dominates Y in CFG if and only if X dominates Y in G. | |
1290 | In this step, we can use arbitrary algorithm to determine dominators. | |
1291 | We decided to prefer the algorithm [3] to the algorithm of | |
1292 | Lengauer and Tarjan, since the set BBS is usually small (rarely exceeding | |
1293 | 10 during gcc bootstrap), and [3] should perform better in this case. | |
1294 | ||
1295 | Finally, we need to determine the immediate dominators for the basic | |
1296 | blocks of BBS. If the immediate dominator of X in G is Y, then | |
1297 | the immediate dominator of X in CFG belongs to the tree of F rooted in | |
1298 | Y. We process the dominator tree T of G recursively, starting from leaves. | |
1299 | Suppose that X_1, X_2, ..., X_k are the sons of Y in T, and that the | |
1300 | subtrees of the dominance tree of CFG rooted in X_i are already correct. | |
1301 | Let G' be the subgraph of G induced by {X_1, X_2, ..., X_k}. We make | |
1302 | the following observations: | |
1303 | (i) the immediate dominator of all blocks in a strongly connected | |
1304 | component of G' is the same | |
1305 | (ii) if X has no predecessors in G', then the immediate dominator of X | |
1306 | is the nearest common ancestor of the predecessors of X in the | |
1307 | subtree of F rooted in Y | |
1308 | Therefore, it suffices to find the topological ordering of G', and | |
1309 | process the nodes X_i in this order using the rules (i) and (ii). | |
1310 | Then, we contract all the nodes X_i with Y in G, so that the further | |
1311 | steps work correctly. */ | |
1312 | ||
1313 | if (!conservative) | |
1314 | { | |
1315 | /* Split the tree now. If the idoms of blocks in BBS are not | |
1316 | conservatively correct, setting the dominators using the | |
1317 | heuristics in prune_bbs_to_update_dominators could | |
1318 | create cycles in the dominance "tree", and cause ICE. */ | |
48148244 | 1319 | FOR_EACH_VEC_ELT (basic_block, bbs, i, bb) |
3f9439d7 | 1320 | set_immediate_dominator (CDI_DOMINATORS, bb, NULL); |
1321 | } | |
1322 | ||
1323 | prune_bbs_to_update_dominators (bbs, conservative); | |
1324 | n = VEC_length (basic_block, bbs); | |
1325 | ||
1326 | if (n == 0) | |
1327 | return; | |
e7f5d6c3 | 1328 | |
3f9439d7 | 1329 | if (n == 1) |
89d75d78 | 1330 | { |
3f9439d7 | 1331 | bb = VEC_index (basic_block, bbs, 0); |
1332 | set_immediate_dominator (CDI_DOMINATORS, bb, | |
1333 | recompute_dominator (CDI_DOMINATORS, bb)); | |
1334 | return; | |
1335 | } | |
1336 | ||
1337 | /* Construct the graph G. */ | |
1338 | map = pointer_map_create (); | |
48148244 | 1339 | FOR_EACH_VEC_ELT (basic_block, bbs, i, bb) |
3f9439d7 | 1340 | { |
1341 | /* If the dominance tree is conservatively correct, split it now. */ | |
1342 | if (conservative) | |
1343 | set_immediate_dominator (CDI_DOMINATORS, bb, NULL); | |
1344 | *pointer_map_insert (map, bb) = (void *) (size_t) i; | |
1345 | } | |
1346 | *pointer_map_insert (map, ENTRY_BLOCK_PTR) = (void *) (size_t) n; | |
1347 | ||
1348 | g = new_graph (n + 1); | |
1349 | for (y = 0; y < g->n_vertices; y++) | |
1350 | g->vertices[y].data = BITMAP_ALLOC (NULL); | |
48148244 | 1351 | FOR_EACH_VEC_ELT (basic_block, bbs, i, bb) |
3f9439d7 | 1352 | { |
1353 | FOR_EACH_EDGE (e, ei, bb->preds) | |
89d75d78 | 1354 | { |
3f9439d7 | 1355 | dom = root_of_dom_tree (CDI_DOMINATORS, e->src); |
1356 | if (dom == bb) | |
1357 | continue; | |
1358 | ||
1359 | dom_i = (size_t) *pointer_map_contains (map, dom); | |
1360 | ||
1361 | /* Do not include parallel edges to G. */ | |
6ef9bbe0 | 1362 | if (!bitmap_set_bit ((bitmap) g->vertices[dom_i].data, i)) |
3f9439d7 | 1363 | continue; |
1364 | ||
3f9439d7 | 1365 | add_edge (g, dom_i, i); |
4794f989 | 1366 | } |
1367 | } | |
3f9439d7 | 1368 | for (y = 0; y < g->n_vertices; y++) |
1369 | BITMAP_FREE (g->vertices[y].data); | |
1370 | pointer_map_destroy (map); | |
1371 | ||
1372 | /* Find the dominator tree of G. */ | |
1373 | son = XNEWVEC (int, n + 1); | |
1374 | brother = XNEWVEC (int, n + 1); | |
1375 | parent = XNEWVEC (int, n + 1); | |
1376 | graphds_domtree (g, n, parent, son, brother); | |
1377 | ||
1378 | /* Finally, traverse the tree and find the immediate dominators. */ | |
1379 | for (y = n; son[y] != -1; y = son[y]) | |
1380 | continue; | |
1381 | while (y != -1) | |
1382 | { | |
1383 | determine_dominators_for_sons (g, bbs, y, son, brother); | |
1384 | ||
1385 | if (brother[y] != -1) | |
1386 | { | |
1387 | y = brother[y]; | |
1388 | while (son[y] != -1) | |
1389 | y = son[y]; | |
1390 | } | |
1391 | else | |
1392 | y = parent[y]; | |
1393 | } | |
1394 | ||
1395 | free (son); | |
1396 | free (brother); | |
1397 | free (parent); | |
e7f5d6c3 | 1398 | |
3f9439d7 | 1399 | free_graph (g); |
89d75d78 | 1400 | } |
4794f989 | 1401 | |
89d75d78 | 1402 | void |
0051c76a | 1403 | add_to_dominance_info (enum cdi_direction dir, basic_block bb) |
89d75d78 | 1404 | { |
50b08d37 | 1405 | unsigned int dir_index = dom_convert_dir_to_idx (dir); |
1406 | ||
1cface39 | 1407 | gcc_checking_assert (dom_computed[dir_index] && !bb->dom[dir_index]); |
0051c76a | 1408 | |
50b08d37 | 1409 | n_bbs_in_dom_tree[dir_index]++; |
48e1416a | 1410 | |
50b08d37 | 1411 | bb->dom[dir_index] = et_new_tree (bb); |
0051c76a | 1412 | |
50b08d37 | 1413 | if (dom_computed[dir_index] == DOM_OK) |
1414 | dom_computed[dir_index] = DOM_NO_FAST_QUERY; | |
89d75d78 | 1415 | } |
1416 | ||
1417 | void | |
0051c76a | 1418 | delete_from_dominance_info (enum cdi_direction dir, basic_block bb) |
1419 | { | |
50b08d37 | 1420 | unsigned int dir_index = dom_convert_dir_to_idx (dir); |
0051c76a | 1421 | |
1cface39 | 1422 | gcc_checking_assert (dom_computed[dir_index]); |
0051c76a | 1423 | |
50b08d37 | 1424 | et_free_tree (bb->dom[dir_index]); |
1425 | bb->dom[dir_index] = NULL; | |
1426 | n_bbs_in_dom_tree[dir_index]--; | |
1427 | ||
1428 | if (dom_computed[dir_index] == DOM_OK) | |
1429 | dom_computed[dir_index] = DOM_NO_FAST_QUERY; | |
0051c76a | 1430 | } |
1431 | ||
1432 | /* Returns the first son of BB in the dominator or postdominator tree | |
1433 | as determined by DIR. */ | |
1434 | ||
1435 | basic_block | |
1436 | first_dom_son (enum cdi_direction dir, basic_block bb) | |
89d75d78 | 1437 | { |
50b08d37 | 1438 | unsigned int dir_index = dom_convert_dir_to_idx (dir); |
1439 | struct et_node *son = bb->dom[dir_index]->son; | |
0051c76a | 1440 | |
364c0c59 | 1441 | return (basic_block) (son ? son->data : NULL); |
0051c76a | 1442 | } |
1443 | ||
1444 | /* Returns the next dominance son after BB in the dominator or postdominator | |
1445 | tree as determined by DIR, or NULL if it was the last one. */ | |
1446 | ||
1447 | basic_block | |
1448 | next_dom_son (enum cdi_direction dir, basic_block bb) | |
1449 | { | |
50b08d37 | 1450 | unsigned int dir_index = dom_convert_dir_to_idx (dir); |
1451 | struct et_node *next = bb->dom[dir_index]->right; | |
0051c76a | 1452 | |
364c0c59 | 1453 | return (basic_block) (next->father->son == next ? NULL : next->data); |
89d75d78 | 1454 | } |
1455 | ||
50b08d37 | 1456 | /* Return dominance availability for dominance info DIR. */ |
1457 | ||
1458 | enum dom_state | |
1459 | dom_info_state (enum cdi_direction dir) | |
1460 | { | |
1461 | unsigned int dir_index = dom_convert_dir_to_idx (dir); | |
1462 | ||
1463 | return dom_computed[dir_index]; | |
1464 | } | |
1465 | ||
1466 | /* Set the dominance availability for dominance info DIR to NEW_STATE. */ | |
1467 | ||
1468 | void | |
1469 | set_dom_info_availability (enum cdi_direction dir, enum dom_state new_state) | |
1470 | { | |
1471 | unsigned int dir_index = dom_convert_dir_to_idx (dir); | |
1472 | ||
1473 | dom_computed[dir_index] = new_state; | |
1474 | } | |
1475 | ||
6b9d2769 | 1476 | /* Returns true if dominance information for direction DIR is available. */ |
1477 | ||
1478 | bool | |
1479 | dom_info_available_p (enum cdi_direction dir) | |
1480 | { | |
50b08d37 | 1481 | unsigned int dir_index = dom_convert_dir_to_idx (dir); |
1482 | ||
1483 | return dom_computed[dir_index] != DOM_NONE; | |
6b9d2769 | 1484 | } |
1485 | ||
4b987fac | 1486 | DEBUG_FUNCTION void |
0051c76a | 1487 | debug_dominance_info (enum cdi_direction dir) |
89d75d78 | 1488 | { |
1489 | basic_block bb, bb2; | |
1490 | FOR_EACH_BB (bb) | |
0051c76a | 1491 | if ((bb2 = get_immediate_dominator (dir, bb))) |
89d75d78 | 1492 | fprintf (stderr, "%i %i\n", bb->index, bb2->index); |
4794f989 | 1493 | } |
0bffc570 | 1494 | |
1495 | /* Prints to stderr representation of the dominance tree (for direction DIR) | |
4a7e4fcc | 1496 | rooted in ROOT, indented by INDENT tabulators. If INDENT_FIRST is false, |
0bffc570 | 1497 | the first line of the output is not indented. */ |
1498 | ||
1499 | static void | |
1500 | debug_dominance_tree_1 (enum cdi_direction dir, basic_block root, | |
1501 | unsigned indent, bool indent_first) | |
1502 | { | |
1503 | basic_block son; | |
1504 | unsigned i; | |
1505 | bool first = true; | |
1506 | ||
1507 | if (indent_first) | |
1508 | for (i = 0; i < indent; i++) | |
1509 | fprintf (stderr, "\t"); | |
1510 | fprintf (stderr, "%d\t", root->index); | |
1511 | ||
1512 | for (son = first_dom_son (dir, root); | |
1513 | son; | |
1514 | son = next_dom_son (dir, son)) | |
1515 | { | |
1516 | debug_dominance_tree_1 (dir, son, indent + 1, !first); | |
1517 | first = false; | |
1518 | } | |
1519 | ||
1520 | if (first) | |
1521 | fprintf (stderr, "\n"); | |
1522 | } | |
1523 | ||
1524 | /* Prints to stderr representation of the dominance tree (for direction DIR) | |
1525 | rooted in ROOT. */ | |
1526 | ||
4b987fac | 1527 | DEBUG_FUNCTION void |
0bffc570 | 1528 | debug_dominance_tree (enum cdi_direction dir, basic_block root) |
1529 | { | |
1530 | debug_dominance_tree_1 (dir, root, 0, false); | |
1531 | } |