Mercurial > hg > truffle
annotate src/share/vm/opto/domgraph.cpp @ 4237:30b6720604d2
Undid expected failure for EscapeAnalysisTest.testMonitor2().
author | Doug Simon <doug.simon@oracle.com> |
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date | Fri, 06 Jan 2012 15:35:52 +0100 |
parents | f95d63e2154a |
children | 5e990493719e |
rev | line source |
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0 | 1 /* |
1972 | 2 * Copyright (c) 1997, 2010, Oracle and/or its affiliates. All rights reserved. |
0 | 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
4 * | |
5 * This code is free software; you can redistribute it and/or modify it | |
6 * under the terms of the GNU General Public License version 2 only, as | |
7 * published by the Free Software Foundation. | |
8 * | |
9 * This code is distributed in the hope that it will be useful, but WITHOUT | |
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
12 * version 2 for more details (a copy is included in the LICENSE file that | |
13 * accompanied this code). | |
14 * | |
15 * You should have received a copy of the GNU General Public License version | |
16 * 2 along with this work; if not, write to the Free Software Foundation, | |
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | |
18 * | |
1552
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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20 * or visit www.oracle.com if you need additional information or have any |
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21 * questions. |
0 | 22 * |
23 */ | |
24 | |
1972 | 25 #include "precompiled.hpp" |
26 #include "libadt/vectset.hpp" | |
27 #include "memory/allocation.hpp" | |
28 #include "opto/block.hpp" | |
29 #include "opto/machnode.hpp" | |
30 #include "opto/phaseX.hpp" | |
31 #include "opto/rootnode.hpp" | |
32 | |
0 | 33 // Portions of code courtesy of Clifford Click |
34 | |
35 // Optimization - Graph Style | |
36 | |
37 //------------------------------Tarjan----------------------------------------- | |
38 // A data structure that holds all the information needed to find dominators. | |
39 struct Tarjan { | |
40 Block *_block; // Basic block for this info | |
41 | |
42 uint _semi; // Semi-dominators | |
43 uint _size; // Used for faster LINK and EVAL | |
44 Tarjan *_parent; // Parent in DFS | |
45 Tarjan *_label; // Used for LINK and EVAL | |
46 Tarjan *_ancestor; // Used for LINK and EVAL | |
47 Tarjan *_child; // Used for faster LINK and EVAL | |
48 Tarjan *_dom; // Parent in dominator tree (immediate dom) | |
49 Tarjan *_bucket; // Set of vertices with given semidominator | |
50 | |
51 Tarjan *_dom_child; // Child in dominator tree | |
52 Tarjan *_dom_next; // Next in dominator tree | |
53 | |
54 // Fast union-find work | |
55 void COMPRESS(); | |
56 Tarjan *EVAL(void); | |
57 void LINK( Tarjan *w, Tarjan *tarjan0 ); | |
58 | |
59 void setdepth( uint size ); | |
60 | |
61 }; | |
62 | |
63 //------------------------------Dominator-------------------------------------- | |
64 // Compute the dominator tree of the CFG. The CFG must already have been | |
65 // constructed. This is the Lengauer & Tarjan O(E-alpha(E,V)) algorithm. | |
66 void PhaseCFG::Dominators( ) { | |
67 // Pre-grow the blocks array, prior to the ResourceMark kicking in | |
68 _blocks.map(_num_blocks,0); | |
69 | |
70 ResourceMark rm; | |
71 // Setup mappings from my Graph to Tarjan's stuff and back | |
72 // Note: Tarjan uses 1-based arrays | |
73 Tarjan *tarjan = NEW_RESOURCE_ARRAY(Tarjan,_num_blocks+1); | |
74 | |
75 // Tarjan's algorithm, almost verbatim: | |
76 // Step 1: | |
77 _rpo_ctr = _num_blocks; | |
78 uint dfsnum = DFS( tarjan ); | |
79 if( dfsnum-1 != _num_blocks ) {// Check for unreachable loops! | |
80 // If the returned dfsnum does not match the number of blocks, then we | |
81 // must have some unreachable loops. These can be made at any time by | |
82 // IterGVN. They are cleaned up by CCP or the loop opts, but the last | |
83 // IterGVN can always make more that are not cleaned up. Highly unlikely | |
84 // except in ZKM.jar, where endless irreducible loops cause the loop opts | |
85 // to not get run. | |
86 // | |
87 // Having found unreachable loops, we have made a bad RPO _block layout. | |
88 // We can re-run the above DFS pass with the correct number of blocks, | |
89 // and hack the Tarjan algorithm below to be robust in the presence of | |
90 // such dead loops (as was done for the NTarjan code farther below). | |
91 // Since this situation is so unlikely, instead I've decided to bail out. | |
92 // CNC 7/24/2001 | |
93 C->record_method_not_compilable("unreachable loop"); | |
94 return; | |
95 } | |
96 _blocks._cnt = _num_blocks; | |
97 | |
98 // Tarjan is using 1-based arrays, so these are some initialize flags | |
99 tarjan[0]._size = tarjan[0]._semi = 0; | |
100 tarjan[0]._label = &tarjan[0]; | |
101 | |
102 uint i; | |
103 for( i=_num_blocks; i>=2; i-- ) { // For all vertices in DFS order | |
104 Tarjan *w = &tarjan[i]; // Get vertex from DFS | |
105 | |
106 // Step 2: | |
107 Node *whead = w->_block->head(); | |
108 for( uint j=1; j < whead->req(); j++ ) { | |
109 Block *b = _bbs[whead->in(j)->_idx]; | |
110 Tarjan *vx = &tarjan[b->_pre_order]; | |
111 Tarjan *u = vx->EVAL(); | |
112 if( u->_semi < w->_semi ) | |
113 w->_semi = u->_semi; | |
114 } | |
115 | |
116 // w is added to a bucket here, and only here. | |
117 // Thus w is in at most one bucket and the sum of all bucket sizes is O(n). | |
118 // Thus bucket can be a linked list. | |
119 // Thus we do not need a small integer name for each Block. | |
120 w->_bucket = tarjan[w->_semi]._bucket; | |
121 tarjan[w->_semi]._bucket = w; | |
122 | |
123 w->_parent->LINK( w, &tarjan[0] ); | |
124 | |
125 // Step 3: | |
126 for( Tarjan *vx = w->_parent->_bucket; vx; vx = vx->_bucket ) { | |
127 Tarjan *u = vx->EVAL(); | |
128 vx->_dom = (u->_semi < vx->_semi) ? u : w->_parent; | |
129 } | |
130 } | |
131 | |
132 // Step 4: | |
133 for( i=2; i <= _num_blocks; i++ ) { | |
134 Tarjan *w = &tarjan[i]; | |
135 if( w->_dom != &tarjan[w->_semi] ) | |
136 w->_dom = w->_dom->_dom; | |
137 w->_dom_next = w->_dom_child = NULL; // Initialize for building tree later | |
138 } | |
139 // No immediate dominator for the root | |
140 Tarjan *w = &tarjan[_broot->_pre_order]; | |
141 w->_dom = NULL; | |
142 w->_dom_next = w->_dom_child = NULL; // Initialize for building tree later | |
143 | |
144 // Convert the dominator tree array into my kind of graph | |
145 for( i=1; i<=_num_blocks;i++){// For all Tarjan vertices | |
146 Tarjan *t = &tarjan[i]; // Handy access | |
147 Tarjan *tdom = t->_dom; // Handy access to immediate dominator | |
148 if( tdom ) { // Root has no immediate dominator | |
149 t->_block->_idom = tdom->_block; // Set immediate dominator | |
150 t->_dom_next = tdom->_dom_child; // Make me a sibling of parent's child | |
151 tdom->_dom_child = t; // Make me a child of my parent | |
152 } else | |
153 t->_block->_idom = NULL; // Root | |
154 } | |
155 w->setdepth( _num_blocks+1 ); // Set depth in dominator tree | |
156 | |
157 } | |
158 | |
159 //----------------------------Block_Stack-------------------------------------- | |
160 class Block_Stack { | |
161 private: | |
162 struct Block_Descr { | |
163 Block *block; // Block | |
164 int index; // Index of block's successor pushed on stack | |
165 int freq_idx; // Index of block's most frequent successor | |
166 }; | |
167 Block_Descr *_stack_top; | |
168 Block_Descr *_stack_max; | |
169 Block_Descr *_stack; | |
170 Tarjan *_tarjan; | |
171 uint most_frequent_successor( Block *b ); | |
172 public: | |
173 Block_Stack(Tarjan *tarjan, int size) : _tarjan(tarjan) { | |
174 _stack = NEW_RESOURCE_ARRAY(Block_Descr, size); | |
175 _stack_max = _stack + size; | |
176 _stack_top = _stack - 1; // stack is empty | |
177 } | |
178 void push(uint pre_order, Block *b) { | |
179 Tarjan *t = &_tarjan[pre_order]; // Fast local access | |
180 b->_pre_order = pre_order; // Flag as visited | |
181 t->_block = b; // Save actual block | |
182 t->_semi = pre_order; // Block to DFS map | |
183 t->_label = t; // DFS to vertex map | |
184 t->_ancestor = NULL; // Fast LINK & EVAL setup | |
185 t->_child = &_tarjan[0]; // Sentenial | |
186 t->_size = 1; | |
187 t->_bucket = NULL; | |
188 if (pre_order == 1) | |
189 t->_parent = NULL; // first block doesn't have parent | |
190 else { | |
605 | 191 // Save parent (current top block on stack) in DFS |
0 | 192 t->_parent = &_tarjan[_stack_top->block->_pre_order]; |
193 } | |
194 // Now put this block on stack | |
195 ++_stack_top; | |
196 assert(_stack_top < _stack_max, ""); // assert if stack have to grow | |
197 _stack_top->block = b; | |
198 _stack_top->index = -1; | |
199 // Find the index into b->succs[] array of the most frequent successor. | |
200 _stack_top->freq_idx = most_frequent_successor(b); // freq_idx >= 0 | |
201 } | |
202 Block* pop() { Block* b = _stack_top->block; _stack_top--; return b; } | |
203 bool is_nonempty() { return (_stack_top >= _stack); } | |
204 bool last_successor() { return (_stack_top->index == _stack_top->freq_idx); } | |
205 Block* next_successor() { | |
206 int i = _stack_top->index; | |
207 i++; | |
208 if (i == _stack_top->freq_idx) i++; | |
209 if (i >= (int)(_stack_top->block->_num_succs)) { | |
210 i = _stack_top->freq_idx; // process most frequent successor last | |
211 } | |
212 _stack_top->index = i; | |
213 return _stack_top->block->_succs[ i ]; | |
214 } | |
215 }; | |
216 | |
217 //-------------------------most_frequent_successor----------------------------- | |
218 // Find the index into the b->succs[] array of the most frequent successor. | |
219 uint Block_Stack::most_frequent_successor( Block *b ) { | |
220 uint freq_idx = 0; | |
221 int eidx = b->end_idx(); | |
222 Node *n = b->_nodes[eidx]; | |
223 int op = n->is_Mach() ? n->as_Mach()->ideal_Opcode() : n->Opcode(); | |
224 switch( op ) { | |
225 case Op_CountedLoopEnd: | |
226 case Op_If: { // Split frequency amongst children | |
227 float prob = n->as_MachIf()->_prob; | |
228 // Is succ[0] the TRUE branch or the FALSE branch? | |
229 if( b->_nodes[eidx+1]->Opcode() == Op_IfFalse ) | |
230 prob = 1.0f - prob; | |
231 freq_idx = prob < PROB_FAIR; // freq=1 for succ[0] < 0.5 prob | |
232 break; | |
233 } | |
234 case Op_Catch: // Split frequency amongst children | |
235 for( freq_idx = 0; freq_idx < b->_num_succs; freq_idx++ ) | |
236 if( b->_nodes[eidx+1+freq_idx]->as_CatchProj()->_con == CatchProjNode::fall_through_index ) | |
237 break; | |
238 // Handle case of no fall-thru (e.g., check-cast MUST throw an exception) | |
239 if( freq_idx == b->_num_succs ) freq_idx = 0; | |
240 break; | |
241 // Currently there is no support for finding out the most | |
242 // frequent successor for jumps, so lets just make it the first one | |
243 case Op_Jump: | |
244 case Op_Root: | |
245 case Op_Goto: | |
246 case Op_NeverBranch: | |
247 freq_idx = 0; // fall thru | |
248 break; | |
249 case Op_TailCall: | |
250 case Op_TailJump: | |
251 case Op_Return: | |
252 case Op_Halt: | |
253 case Op_Rethrow: | |
254 break; | |
255 default: | |
256 ShouldNotReachHere(); | |
257 } | |
258 return freq_idx; | |
259 } | |
260 | |
261 //------------------------------DFS-------------------------------------------- | |
262 // Perform DFS search. Setup 'vertex' as DFS to vertex mapping. Setup | |
263 // 'semi' as vertex to DFS mapping. Set 'parent' to DFS parent. | |
264 uint PhaseCFG::DFS( Tarjan *tarjan ) { | |
265 Block *b = _broot; | |
266 uint pre_order = 1; | |
267 // Allocate stack of size _num_blocks+1 to avoid frequent realloc | |
268 Block_Stack bstack(tarjan, _num_blocks+1); | |
269 | |
270 // Push on stack the state for the first block | |
271 bstack.push(pre_order, b); | |
272 ++pre_order; | |
273 | |
274 while (bstack.is_nonempty()) { | |
275 if (!bstack.last_successor()) { | |
276 // Walk over all successors in pre-order (DFS). | |
277 Block *s = bstack.next_successor(); | |
278 if (s->_pre_order == 0) { // Check for no-pre-order, not-visited | |
279 // Push on stack the state of successor | |
280 bstack.push(pre_order, s); | |
281 ++pre_order; | |
282 } | |
283 } | |
284 else { | |
285 // Build a reverse post-order in the CFG _blocks array | |
286 Block *stack_top = bstack.pop(); | |
287 stack_top->_rpo = --_rpo_ctr; | |
288 _blocks.map(stack_top->_rpo, stack_top); | |
289 } | |
290 } | |
291 return pre_order; | |
292 } | |
293 | |
294 //------------------------------COMPRESS--------------------------------------- | |
295 void Tarjan::COMPRESS() | |
296 { | |
297 assert( _ancestor != 0, "" ); | |
298 if( _ancestor->_ancestor != 0 ) { | |
299 _ancestor->COMPRESS( ); | |
300 if( _ancestor->_label->_semi < _label->_semi ) | |
301 _label = _ancestor->_label; | |
302 _ancestor = _ancestor->_ancestor; | |
303 } | |
304 } | |
305 | |
306 //------------------------------EVAL------------------------------------------- | |
307 Tarjan *Tarjan::EVAL() { | |
308 if( !_ancestor ) return _label; | |
309 COMPRESS(); | |
310 return (_ancestor->_label->_semi >= _label->_semi) ? _label : _ancestor->_label; | |
311 } | |
312 | |
313 //------------------------------LINK------------------------------------------- | |
314 void Tarjan::LINK( Tarjan *w, Tarjan *tarjan0 ) { | |
315 Tarjan *s = w; | |
316 while( w->_label->_semi < s->_child->_label->_semi ) { | |
317 if( s->_size + s->_child->_child->_size >= (s->_child->_size << 1) ) { | |
318 s->_child->_ancestor = s; | |
319 s->_child = s->_child->_child; | |
320 } else { | |
321 s->_child->_size = s->_size; | |
322 s = s->_ancestor = s->_child; | |
323 } | |
324 } | |
325 s->_label = w->_label; | |
326 _size += w->_size; | |
327 if( _size < (w->_size << 1) ) { | |
328 Tarjan *tmp = s; s = _child; _child = tmp; | |
329 } | |
330 while( s != tarjan0 ) { | |
331 s->_ancestor = this; | |
332 s = s->_child; | |
333 } | |
334 } | |
335 | |
336 //------------------------------setdepth--------------------------------------- | |
337 void Tarjan::setdepth( uint stack_size ) { | |
338 Tarjan **top = NEW_RESOURCE_ARRAY(Tarjan*, stack_size); | |
339 Tarjan **next = top; | |
340 Tarjan **last; | |
341 uint depth = 0; | |
342 *top = this; | |
343 ++top; | |
344 do { | |
345 // next level | |
346 ++depth; | |
347 last = top; | |
348 do { | |
349 // Set current depth for all tarjans on this level | |
350 Tarjan *t = *next; // next tarjan from stack | |
351 ++next; | |
352 do { | |
353 t->_block->_dom_depth = depth; // Set depth in dominator tree | |
354 Tarjan *dom_child = t->_dom_child; | |
355 t = t->_dom_next; // next tarjan | |
356 if (dom_child != NULL) { | |
357 *top = dom_child; // save child on stack | |
358 ++top; | |
359 } | |
360 } while (t != NULL); | |
361 } while (next < last); | |
362 } while (last < top); | |
363 } | |
364 | |
365 //*********************** DOMINATORS ON THE SEA OF NODES*********************** | |
366 //------------------------------NTarjan---------------------------------------- | |
367 // A data structure that holds all the information needed to find dominators. | |
368 struct NTarjan { | |
369 Node *_control; // Control node associated with this info | |
370 | |
371 uint _semi; // Semi-dominators | |
372 uint _size; // Used for faster LINK and EVAL | |
373 NTarjan *_parent; // Parent in DFS | |
374 NTarjan *_label; // Used for LINK and EVAL | |
375 NTarjan *_ancestor; // Used for LINK and EVAL | |
376 NTarjan *_child; // Used for faster LINK and EVAL | |
377 NTarjan *_dom; // Parent in dominator tree (immediate dom) | |
378 NTarjan *_bucket; // Set of vertices with given semidominator | |
379 | |
380 NTarjan *_dom_child; // Child in dominator tree | |
381 NTarjan *_dom_next; // Next in dominator tree | |
382 | |
383 // Perform DFS search. | |
384 // Setup 'vertex' as DFS to vertex mapping. | |
385 // Setup 'semi' as vertex to DFS mapping. | |
386 // Set 'parent' to DFS parent. | |
387 static int DFS( NTarjan *ntarjan, VectorSet &visited, PhaseIdealLoop *pil, uint *dfsorder ); | |
388 void setdepth( uint size, uint *dom_depth ); | |
389 | |
390 // Fast union-find work | |
391 void COMPRESS(); | |
392 NTarjan *EVAL(void); | |
393 void LINK( NTarjan *w, NTarjan *ntarjan0 ); | |
394 #ifndef PRODUCT | |
395 void dump(int offset) const; | |
396 #endif | |
397 }; | |
398 | |
399 //------------------------------Dominator-------------------------------------- | |
400 // Compute the dominator tree of the sea of nodes. This version walks all CFG | |
401 // nodes (using the is_CFG() call) and places them in a dominator tree. Thus, | |
402 // it needs a count of the CFG nodes for the mapping table. This is the | |
403 // Lengauer & Tarjan O(E-alpha(E,V)) algorithm. | |
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404 void PhaseIdealLoop::Dominators() { |
0 | 405 ResourceMark rm; |
406 // Setup mappings from my Graph to Tarjan's stuff and back | |
407 // Note: Tarjan uses 1-based arrays | |
408 NTarjan *ntarjan = NEW_RESOURCE_ARRAY(NTarjan,C->unique()+1); | |
409 // Initialize _control field for fast reference | |
410 int i; | |
411 for( i= C->unique()-1; i>=0; i-- ) | |
412 ntarjan[i]._control = NULL; | |
413 | |
414 // Store the DFS order for the main loop | |
415 uint *dfsorder = NEW_RESOURCE_ARRAY(uint,C->unique()+1); | |
416 memset(dfsorder, max_uint, (C->unique()+1) * sizeof(uint)); | |
417 | |
418 // Tarjan's algorithm, almost verbatim: | |
419 // Step 1: | |
420 VectorSet visited(Thread::current()->resource_area()); | |
421 int dfsnum = NTarjan::DFS( ntarjan, visited, this, dfsorder); | |
422 | |
423 // Tarjan is using 1-based arrays, so these are some initialize flags | |
424 ntarjan[0]._size = ntarjan[0]._semi = 0; | |
425 ntarjan[0]._label = &ntarjan[0]; | |
426 | |
427 for( i = dfsnum-1; i>1; i-- ) { // For all nodes in reverse DFS order | |
428 NTarjan *w = &ntarjan[i]; // Get Node from DFS | |
429 assert(w->_control != NULL,"bad DFS walk"); | |
430 | |
431 // Step 2: | |
432 Node *whead = w->_control; | |
433 for( uint j=0; j < whead->req(); j++ ) { // For each predecessor | |
434 if( whead->in(j) == NULL || !whead->in(j)->is_CFG() ) | |
435 continue; // Only process control nodes | |
436 uint b = dfsorder[whead->in(j)->_idx]; | |
437 if(b == max_uint) continue; | |
438 NTarjan *vx = &ntarjan[b]; | |
439 NTarjan *u = vx->EVAL(); | |
440 if( u->_semi < w->_semi ) | |
441 w->_semi = u->_semi; | |
442 } | |
443 | |
444 // w is added to a bucket here, and only here. | |
445 // Thus w is in at most one bucket and the sum of all bucket sizes is O(n). | |
446 // Thus bucket can be a linked list. | |
447 w->_bucket = ntarjan[w->_semi]._bucket; | |
448 ntarjan[w->_semi]._bucket = w; | |
449 | |
450 w->_parent->LINK( w, &ntarjan[0] ); | |
451 | |
452 // Step 3: | |
453 for( NTarjan *vx = w->_parent->_bucket; vx; vx = vx->_bucket ) { | |
454 NTarjan *u = vx->EVAL(); | |
455 vx->_dom = (u->_semi < vx->_semi) ? u : w->_parent; | |
456 } | |
457 | |
458 // Cleanup any unreachable loops now. Unreachable loops are loops that | |
459 // flow into the main graph (and hence into ROOT) but are not reachable | |
460 // from above. Such code is dead, but requires a global pass to detect | |
461 // it; this global pass was the 'build_loop_tree' pass run just prior. | |
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462 if( !_verify_only && whead->is_Region() ) { |
0 | 463 for( uint i = 1; i < whead->req(); i++ ) { |
464 if (!has_node(whead->in(i))) { | |
465 // Kill dead input path | |
466 assert( !visited.test(whead->in(i)->_idx), | |
467 "input with no loop must be dead" ); | |
468 _igvn.hash_delete(whead); | |
469 whead->del_req(i); | |
470 _igvn._worklist.push(whead); | |
471 for (DUIterator_Fast jmax, j = whead->fast_outs(jmax); j < jmax; j++) { | |
472 Node* p = whead->fast_out(j); | |
473 if( p->is_Phi() ) { | |
474 _igvn.hash_delete(p); | |
475 p->del_req(i); | |
476 _igvn._worklist.push(p); | |
477 } | |
478 } | |
479 i--; // Rerun same iteration | |
480 } // End of if dead input path | |
481 } // End of for all input paths | |
482 } // End if if whead is a Region | |
483 } // End of for all Nodes in reverse DFS order | |
484 | |
485 // Step 4: | |
486 for( i=2; i < dfsnum; i++ ) { // DFS order | |
487 NTarjan *w = &ntarjan[i]; | |
488 assert(w->_control != NULL,"Bad DFS walk"); | |
489 if( w->_dom != &ntarjan[w->_semi] ) | |
490 w->_dom = w->_dom->_dom; | |
491 w->_dom_next = w->_dom_child = NULL; // Initialize for building tree later | |
492 } | |
493 // No immediate dominator for the root | |
494 NTarjan *w = &ntarjan[dfsorder[C->root()->_idx]]; | |
495 w->_dom = NULL; | |
496 w->_parent = NULL; | |
497 w->_dom_next = w->_dom_child = NULL; // Initialize for building tree later | |
498 | |
499 // Convert the dominator tree array into my kind of graph | |
500 for( i=1; i<dfsnum; i++ ) { // For all Tarjan vertices | |
501 NTarjan *t = &ntarjan[i]; // Handy access | |
502 assert(t->_control != NULL,"Bad DFS walk"); | |
503 NTarjan *tdom = t->_dom; // Handy access to immediate dominator | |
504 if( tdom ) { // Root has no immediate dominator | |
505 _idom[t->_control->_idx] = tdom->_control; // Set immediate dominator | |
506 t->_dom_next = tdom->_dom_child; // Make me a sibling of parent's child | |
507 tdom->_dom_child = t; // Make me a child of my parent | |
508 } else | |
509 _idom[C->root()->_idx] = NULL; // Root | |
510 } | |
511 w->setdepth( C->unique()+1, _dom_depth ); // Set depth in dominator tree | |
512 // Pick up the 'top' node as well | |
513 _idom [C->top()->_idx] = C->root(); | |
514 _dom_depth[C->top()->_idx] = 1; | |
515 | |
516 // Debug Print of Dominator tree | |
517 if( PrintDominators ) { | |
518 #ifndef PRODUCT | |
519 w->dump(0); | |
520 #endif | |
521 } | |
522 } | |
523 | |
524 //------------------------------DFS-------------------------------------------- | |
525 // Perform DFS search. Setup 'vertex' as DFS to vertex mapping. Setup | |
526 // 'semi' as vertex to DFS mapping. Set 'parent' to DFS parent. | |
527 int NTarjan::DFS( NTarjan *ntarjan, VectorSet &visited, PhaseIdealLoop *pil, uint *dfsorder) { | |
528 // Allocate stack of size C->unique()/8 to avoid frequent realloc | |
529 GrowableArray <Node *> dfstack(pil->C->unique() >> 3); | |
530 Node *b = pil->C->root(); | |
531 int dfsnum = 1; | |
532 dfsorder[b->_idx] = dfsnum; // Cache parent's dfsnum for a later use | |
533 dfstack.push(b); | |
534 | |
535 while (dfstack.is_nonempty()) { | |
536 b = dfstack.pop(); | |
537 if( !visited.test_set(b->_idx) ) { // Test node and flag it as visited | |
538 NTarjan *w = &ntarjan[dfsnum]; | |
539 // Only fully process control nodes | |
540 w->_control = b; // Save actual node | |
541 // Use parent's cached dfsnum to identify "Parent in DFS" | |
542 w->_parent = &ntarjan[dfsorder[b->_idx]]; | |
543 dfsorder[b->_idx] = dfsnum; // Save DFS order info | |
544 w->_semi = dfsnum; // Node to DFS map | |
545 w->_label = w; // DFS to vertex map | |
546 w->_ancestor = NULL; // Fast LINK & EVAL setup | |
547 w->_child = &ntarjan[0]; // Sentinal | |
548 w->_size = 1; | |
549 w->_bucket = NULL; | |
550 | |
551 // Need DEF-USE info for this pass | |
552 for ( int i = b->outcnt(); i-- > 0; ) { // Put on stack backwards | |
553 Node* s = b->raw_out(i); // Get a use | |
554 // CFG nodes only and not dead stuff | |
555 if( s->is_CFG() && pil->has_node(s) && !visited.test(s->_idx) ) { | |
556 dfsorder[s->_idx] = dfsnum; // Cache parent's dfsnum for a later use | |
557 dfstack.push(s); | |
558 } | |
559 } | |
560 dfsnum++; // update after parent's dfsnum has been cached. | |
561 } | |
562 } | |
563 | |
564 return dfsnum; | |
565 } | |
566 | |
567 //------------------------------COMPRESS--------------------------------------- | |
568 void NTarjan::COMPRESS() | |
569 { | |
570 assert( _ancestor != 0, "" ); | |
571 if( _ancestor->_ancestor != 0 ) { | |
572 _ancestor->COMPRESS( ); | |
573 if( _ancestor->_label->_semi < _label->_semi ) | |
574 _label = _ancestor->_label; | |
575 _ancestor = _ancestor->_ancestor; | |
576 } | |
577 } | |
578 | |
579 //------------------------------EVAL------------------------------------------- | |
580 NTarjan *NTarjan::EVAL() { | |
581 if( !_ancestor ) return _label; | |
582 COMPRESS(); | |
583 return (_ancestor->_label->_semi >= _label->_semi) ? _label : _ancestor->_label; | |
584 } | |
585 | |
586 //------------------------------LINK------------------------------------------- | |
587 void NTarjan::LINK( NTarjan *w, NTarjan *ntarjan0 ) { | |
588 NTarjan *s = w; | |
589 while( w->_label->_semi < s->_child->_label->_semi ) { | |
590 if( s->_size + s->_child->_child->_size >= (s->_child->_size << 1) ) { | |
591 s->_child->_ancestor = s; | |
592 s->_child = s->_child->_child; | |
593 } else { | |
594 s->_child->_size = s->_size; | |
595 s = s->_ancestor = s->_child; | |
596 } | |
597 } | |
598 s->_label = w->_label; | |
599 _size += w->_size; | |
600 if( _size < (w->_size << 1) ) { | |
601 NTarjan *tmp = s; s = _child; _child = tmp; | |
602 } | |
603 while( s != ntarjan0 ) { | |
604 s->_ancestor = this; | |
605 s = s->_child; | |
606 } | |
607 } | |
608 | |
609 //------------------------------setdepth--------------------------------------- | |
610 void NTarjan::setdepth( uint stack_size, uint *dom_depth ) { | |
611 NTarjan **top = NEW_RESOURCE_ARRAY(NTarjan*, stack_size); | |
612 NTarjan **next = top; | |
613 NTarjan **last; | |
614 uint depth = 0; | |
615 *top = this; | |
616 ++top; | |
617 do { | |
618 // next level | |
619 ++depth; | |
620 last = top; | |
621 do { | |
622 // Set current depth for all tarjans on this level | |
623 NTarjan *t = *next; // next tarjan from stack | |
624 ++next; | |
625 do { | |
626 dom_depth[t->_control->_idx] = depth; // Set depth in dominator tree | |
627 NTarjan *dom_child = t->_dom_child; | |
628 t = t->_dom_next; // next tarjan | |
629 if (dom_child != NULL) { | |
630 *top = dom_child; // save child on stack | |
631 ++top; | |
632 } | |
633 } while (t != NULL); | |
634 } while (next < last); | |
635 } while (last < top); | |
636 } | |
637 | |
638 //------------------------------dump------------------------------------------- | |
639 #ifndef PRODUCT | |
640 void NTarjan::dump(int offset) const { | |
641 // Dump the data from this node | |
642 int i; | |
643 for(i = offset; i >0; i--) // Use indenting for tree structure | |
644 tty->print(" "); | |
645 tty->print("Dominator Node: "); | |
646 _control->dump(); // Control node for this dom node | |
647 tty->print("\n"); | |
648 for(i = offset; i >0; i--) // Use indenting for tree structure | |
649 tty->print(" "); | |
650 tty->print("semi:%d, size:%d\n",_semi, _size); | |
651 for(i = offset; i >0; i--) // Use indenting for tree structure | |
652 tty->print(" "); | |
653 tty->print("DFS Parent: "); | |
654 if(_parent != NULL) | |
655 _parent->_control->dump(); // Parent in DFS | |
656 tty->print("\n"); | |
657 for(i = offset; i >0; i--) // Use indenting for tree structure | |
658 tty->print(" "); | |
659 tty->print("Dom Parent: "); | |
660 if(_dom != NULL) | |
661 _dom->_control->dump(); // Parent in Dominator Tree | |
662 tty->print("\n"); | |
663 | |
664 // Recurse over remaining tree | |
665 if( _dom_child ) _dom_child->dump(offset+2); // Children in dominator tree | |
666 if( _dom_next ) _dom_next ->dump(offset ); // Siblings in dominator tree | |
667 | |
668 } | |
669 #endif |