Mercurial > hg > truffle
annotate src/share/vm/opto/block.cpp @ 4128:f1391adc6681
7112034: Parallel CMS fails to properly mark reference objects
Summary: Enabled reference processing when work stealing during concurrent marking
Reviewed-by: jmasa, brutisso
author | stefank |
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date | Mon, 28 Nov 2011 10:19:26 +0100 |
parents | f94227b6117b |
children | 1bd45abaa507 |
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.inline.hpp" | |
28 #include "opto/block.hpp" | |
29 #include "opto/cfgnode.hpp" | |
30 #include "opto/chaitin.hpp" | |
31 #include "opto/loopnode.hpp" | |
32 #include "opto/machnode.hpp" | |
33 #include "opto/matcher.hpp" | |
34 #include "opto/opcodes.hpp" | |
35 #include "opto/rootnode.hpp" | |
36 #include "utilities/copy.hpp" | |
0 | 37 |
1972 | 38 // Optimization - Graph Style |
0 | 39 |
40 | |
41 //----------------------------------------------------------------------------- | |
42 void Block_Array::grow( uint i ) { | |
43 assert(i >= Max(), "must be an overflow"); | |
44 debug_only(_limit = i+1); | |
45 if( i < _size ) return; | |
46 if( !_size ) { | |
47 _size = 1; | |
48 _blocks = (Block**)_arena->Amalloc( _size * sizeof(Block*) ); | |
49 _blocks[0] = NULL; | |
50 } | |
51 uint old = _size; | |
52 while( i >= _size ) _size <<= 1; // Double to fit | |
53 _blocks = (Block**)_arena->Arealloc( _blocks, old*sizeof(Block*),_size*sizeof(Block*)); | |
54 Copy::zero_to_bytes( &_blocks[old], (_size-old)*sizeof(Block*) ); | |
55 } | |
56 | |
57 //============================================================================= | |
58 void Block_List::remove(uint i) { | |
59 assert(i < _cnt, "index out of bounds"); | |
60 Copy::conjoint_words_to_lower((HeapWord*)&_blocks[i+1], (HeapWord*)&_blocks[i], ((_cnt-i-1)*sizeof(Block*))); | |
61 pop(); // shrink list by one block | |
62 } | |
63 | |
64 void Block_List::insert(uint i, Block *b) { | |
65 push(b); // grow list by one block | |
66 Copy::conjoint_words_to_higher((HeapWord*)&_blocks[i], (HeapWord*)&_blocks[i+1], ((_cnt-i-1)*sizeof(Block*))); | |
67 _blocks[i] = b; | |
68 } | |
69 | |
418 | 70 #ifndef PRODUCT |
71 void Block_List::print() { | |
72 for (uint i=0; i < size(); i++) { | |
73 tty->print("B%d ", _blocks[i]->_pre_order); | |
74 } | |
75 tty->print("size = %d\n", size()); | |
76 } | |
77 #endif | |
0 | 78 |
79 //============================================================================= | |
80 | |
81 uint Block::code_alignment() { | |
82 // Check for Root block | |
3851 | 83 if (_pre_order == 0) return CodeEntryAlignment; |
0 | 84 // Check for Start block |
3851 | 85 if (_pre_order == 1) return InteriorEntryAlignment; |
0 | 86 // Check for loop alignment |
3851 | 87 if (has_loop_alignment()) return loop_alignment(); |
418 | 88 |
3851 | 89 return relocInfo::addr_unit(); // no particular alignment |
418 | 90 } |
91 | |
92 uint Block::compute_loop_alignment() { | |
0 | 93 Node *h = head(); |
3851 | 94 int unit_sz = relocInfo::addr_unit(); |
95 if (h->is_Loop() && h->as_Loop()->is_inner_loop()) { | |
0 | 96 // Pre- and post-loops have low trip count so do not bother with |
97 // NOPs for align loop head. The constants are hidden from tuning | |
98 // but only because my "divide by 4" heuristic surely gets nearly | |
99 // all possible gain (a "do not align at all" heuristic has a | |
100 // chance of getting a really tiny gain). | |
3851 | 101 if (h->is_CountedLoop() && (h->as_CountedLoop()->is_pre_loop() || |
102 h->as_CountedLoop()->is_post_loop())) { | |
103 return (OptoLoopAlignment > 4*unit_sz) ? (OptoLoopAlignment>>2) : unit_sz; | |
104 } | |
0 | 105 // Loops with low backedge frequency should not be aligned. |
106 Node *n = h->in(LoopNode::LoopBackControl)->in(0); | |
3851 | 107 if (n->is_MachIf() && n->as_MachIf()->_prob < 0.01) { |
108 return unit_sz; // Loop does not loop, more often than not! | |
0 | 109 } |
110 return OptoLoopAlignment; // Otherwise align loop head | |
111 } | |
418 | 112 |
3851 | 113 return unit_sz; // no particular alignment |
0 | 114 } |
115 | |
116 //----------------------------------------------------------------------------- | |
117 // Compute the size of first 'inst_cnt' instructions in this block. | |
118 // Return the number of instructions left to compute if the block has | |
418 | 119 // less then 'inst_cnt' instructions. Stop, and return 0 if sum_size |
120 // exceeds OptoLoopAlignment. | |
0 | 121 uint Block::compute_first_inst_size(uint& sum_size, uint inst_cnt, |
122 PhaseRegAlloc* ra) { | |
123 uint last_inst = _nodes.size(); | |
124 for( uint j = 0; j < last_inst && inst_cnt > 0; j++ ) { | |
125 uint inst_size = _nodes[j]->size(ra); | |
126 if( inst_size > 0 ) { | |
127 inst_cnt--; | |
128 uint sz = sum_size + inst_size; | |
129 if( sz <= (uint)OptoLoopAlignment ) { | |
130 // Compute size of instructions which fit into fetch buffer only | |
131 // since all inst_cnt instructions will not fit even if we align them. | |
132 sum_size = sz; | |
133 } else { | |
134 return 0; | |
135 } | |
136 } | |
137 } | |
138 return inst_cnt; | |
139 } | |
140 | |
141 //----------------------------------------------------------------------------- | |
142 uint Block::find_node( const Node *n ) const { | |
143 for( uint i = 0; i < _nodes.size(); i++ ) { | |
144 if( _nodes[i] == n ) | |
145 return i; | |
146 } | |
147 ShouldNotReachHere(); | |
148 return 0; | |
149 } | |
150 | |
151 // Find and remove n from block list | |
152 void Block::find_remove( const Node *n ) { | |
153 _nodes.remove(find_node(n)); | |
154 } | |
155 | |
156 //------------------------------is_Empty--------------------------------------- | |
157 // Return empty status of a block. Empty blocks contain only the head, other | |
158 // ideal nodes, and an optional trailing goto. | |
159 int Block::is_Empty() const { | |
160 | |
161 // Root or start block is not considered empty | |
162 if (head()->is_Root() || head()->is_Start()) { | |
163 return not_empty; | |
164 } | |
165 | |
166 int success_result = completely_empty; | |
167 int end_idx = _nodes.size()-1; | |
168 | |
169 // Check for ending goto | |
3842 | 170 if ((end_idx > 0) && (_nodes[end_idx]->is_MachGoto())) { |
0 | 171 success_result = empty_with_goto; |
172 end_idx--; | |
173 } | |
174 | |
175 // Unreachable blocks are considered empty | |
176 if (num_preds() <= 1) { | |
177 return success_result; | |
178 } | |
179 | |
180 // Ideal nodes are allowable in empty blocks: skip them Only MachNodes | |
181 // turn directly into code, because only MachNodes have non-trivial | |
182 // emit() functions. | |
183 while ((end_idx > 0) && !_nodes[end_idx]->is_Mach()) { | |
184 end_idx--; | |
185 } | |
186 | |
187 // No room for any interesting instructions? | |
188 if (end_idx == 0) { | |
189 return success_result; | |
190 } | |
191 | |
192 return not_empty; | |
193 } | |
194 | |
195 //------------------------------has_uncommon_code------------------------------ | |
605 | 196 // Return true if the block's code implies that it is likely to be |
0 | 197 // executed infrequently. Check to see if the block ends in a Halt or |
198 // a low probability call. | |
199 bool Block::has_uncommon_code() const { | |
200 Node* en = end(); | |
201 | |
3842 | 202 if (en->is_MachGoto()) |
0 | 203 en = en->in(0); |
204 if (en->is_Catch()) | |
205 en = en->in(0); | |
3842 | 206 if (en->is_MachProj() && en->in(0)->is_MachCall()) { |
0 | 207 MachCallNode* call = en->in(0)->as_MachCall(); |
208 if (call->cnt() != COUNT_UNKNOWN && call->cnt() <= PROB_UNLIKELY_MAG(4)) { | |
209 // This is true for slow-path stubs like new_{instance,array}, | |
210 // slow_arraycopy, complete_monitor_locking, uncommon_trap. | |
211 // The magic number corresponds to the probability of an uncommon_trap, | |
212 // even though it is a count not a probability. | |
213 return true; | |
214 } | |
215 } | |
216 | |
217 int op = en->is_Mach() ? en->as_Mach()->ideal_Opcode() : en->Opcode(); | |
218 return op == Op_Halt; | |
219 } | |
220 | |
221 //------------------------------is_uncommon------------------------------------ | |
222 // True if block is low enough frequency or guarded by a test which | |
223 // mostly does not go here. | |
224 bool Block::is_uncommon( Block_Array &bbs ) const { | |
225 // Initial blocks must never be moved, so are never uncommon. | |
226 if (head()->is_Root() || head()->is_Start()) return false; | |
227 | |
228 // Check for way-low freq | |
229 if( _freq < BLOCK_FREQUENCY(0.00001f) ) return true; | |
230 | |
231 // Look for code shape indicating uncommon_trap or slow path | |
232 if (has_uncommon_code()) return true; | |
233 | |
234 const float epsilon = 0.05f; | |
235 const float guard_factor = PROB_UNLIKELY_MAG(4) / (1.f - epsilon); | |
236 uint uncommon_preds = 0; | |
237 uint freq_preds = 0; | |
238 uint uncommon_for_freq_preds = 0; | |
239 | |
240 for( uint i=1; i<num_preds(); i++ ) { | |
241 Block* guard = bbs[pred(i)->_idx]; | |
242 // Check to see if this block follows its guard 1 time out of 10000 | |
243 // or less. | |
244 // | |
245 // See list of magnitude-4 unlikely probabilities in cfgnode.hpp which | |
246 // we intend to be "uncommon", such as slow-path TLE allocation, | |
247 // predicted call failure, and uncommon trap triggers. | |
248 // | |
249 // Use an epsilon value of 5% to allow for variability in frequency | |
250 // predictions and floating point calculations. The net effect is | |
251 // that guard_factor is set to 9500. | |
252 // | |
253 // Ignore low-frequency blocks. | |
254 // The next check is (guard->_freq < 1.e-5 * 9500.). | |
255 if(guard->_freq*BLOCK_FREQUENCY(guard_factor) < BLOCK_FREQUENCY(0.00001f)) { | |
256 uncommon_preds++; | |
257 } else { | |
258 freq_preds++; | |
259 if( _freq < guard->_freq * guard_factor ) { | |
260 uncommon_for_freq_preds++; | |
261 } | |
262 } | |
263 } | |
264 if( num_preds() > 1 && | |
265 // The block is uncommon if all preds are uncommon or | |
266 (uncommon_preds == (num_preds()-1) || | |
267 // it is uncommon for all frequent preds. | |
268 uncommon_for_freq_preds == freq_preds) ) { | |
269 return true; | |
270 } | |
271 return false; | |
272 } | |
273 | |
274 //------------------------------dump------------------------------------------- | |
275 #ifndef PRODUCT | |
3851 | 276 void Block::dump_bidx(const Block* orig, outputStream* st) const { |
277 if (_pre_order) st->print("B%d",_pre_order); | |
278 else st->print("N%d", head()->_idx); | |
0 | 279 |
280 if (Verbose && orig != this) { | |
281 // Dump the original block's idx | |
3851 | 282 st->print(" ("); |
283 orig->dump_bidx(orig, st); | |
284 st->print(")"); | |
0 | 285 } |
286 } | |
287 | |
3851 | 288 void Block::dump_pred(const Block_Array *bbs, Block* orig, outputStream* st) const { |
0 | 289 if (is_connector()) { |
290 for (uint i=1; i<num_preds(); i++) { | |
291 Block *p = ((*bbs)[pred(i)->_idx]); | |
3851 | 292 p->dump_pred(bbs, orig, st); |
0 | 293 } |
294 } else { | |
3851 | 295 dump_bidx(orig, st); |
296 st->print(" "); | |
0 | 297 } |
298 } | |
299 | |
3851 | 300 void Block::dump_head( const Block_Array *bbs, outputStream* st ) const { |
0 | 301 // Print the basic block |
3851 | 302 dump_bidx(this, st); |
303 st->print(": #\t"); | |
0 | 304 |
305 // Print the incoming CFG edges and the outgoing CFG edges | |
306 for( uint i=0; i<_num_succs; i++ ) { | |
3851 | 307 non_connector_successor(i)->dump_bidx(_succs[i], st); |
308 st->print(" "); | |
0 | 309 } |
3851 | 310 st->print("<- "); |
0 | 311 if( head()->is_block_start() ) { |
312 for (uint i=1; i<num_preds(); i++) { | |
313 Node *s = pred(i); | |
314 if (bbs) { | |
315 Block *p = (*bbs)[s->_idx]; | |
3851 | 316 p->dump_pred(bbs, p, st); |
0 | 317 } else { |
318 while (!s->is_block_start()) | |
319 s = s->in(0); | |
3851 | 320 st->print("N%d ", s->_idx ); |
0 | 321 } |
322 } | |
323 } else | |
3851 | 324 st->print("BLOCK HEAD IS JUNK "); |
0 | 325 |
326 // Print loop, if any | |
327 const Block *bhead = this; // Head of self-loop | |
328 Node *bh = bhead->head(); | |
329 if( bbs && bh->is_Loop() && !head()->is_Root() ) { | |
330 LoopNode *loop = bh->as_Loop(); | |
331 const Block *bx = (*bbs)[loop->in(LoopNode::LoopBackControl)->_idx]; | |
332 while (bx->is_connector()) { | |
333 bx = (*bbs)[bx->pred(1)->_idx]; | |
334 } | |
3851 | 335 st->print("\tLoop: B%d-B%d ", bhead->_pre_order, bx->_pre_order); |
0 | 336 // Dump any loop-specific bits, especially for CountedLoops. |
3851 | 337 loop->dump_spec(st); |
418 | 338 } else if (has_loop_alignment()) { |
3851 | 339 st->print(" top-of-loop"); |
0 | 340 } |
3851 | 341 st->print(" Freq: %g",_freq); |
0 | 342 if( Verbose || WizardMode ) { |
3851 | 343 st->print(" IDom: %d/#%d", _idom ? _idom->_pre_order : 0, _dom_depth); |
344 st->print(" RegPressure: %d",_reg_pressure); | |
345 st->print(" IHRP Index: %d",_ihrp_index); | |
346 st->print(" FRegPressure: %d",_freg_pressure); | |
347 st->print(" FHRP Index: %d",_fhrp_index); | |
0 | 348 } |
3851 | 349 st->print_cr(""); |
0 | 350 } |
351 | |
3851 | 352 void Block::dump() const { dump(NULL); } |
0 | 353 |
354 void Block::dump( const Block_Array *bbs ) const { | |
355 dump_head(bbs); | |
356 uint cnt = _nodes.size(); | |
357 for( uint i=0; i<cnt; i++ ) | |
358 _nodes[i]->dump(); | |
359 tty->print("\n"); | |
360 } | |
361 #endif | |
362 | |
363 //============================================================================= | |
364 //------------------------------PhaseCFG--------------------------------------- | |
365 PhaseCFG::PhaseCFG( Arena *a, RootNode *r, Matcher &m ) : | |
366 Phase(CFG), | |
367 _bbs(a), | |
1685 | 368 _root(r), |
369 _node_latency(NULL) | |
0 | 370 #ifndef PRODUCT |
371 , _trace_opto_pipelining(TraceOptoPipelining || C->method_has_option("TraceOptoPipelining")) | |
372 #endif | |
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373 #ifdef ASSERT |
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374 , _raw_oops(a) |
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375 #endif |
0 | 376 { |
377 ResourceMark rm; | |
378 // I'll need a few machine-specific GotoNodes. Make an Ideal GotoNode, | |
379 // then Match it into a machine-specific Node. Then clone the machine | |
380 // Node on demand. | |
381 Node *x = new (C, 1) GotoNode(NULL); | |
382 x->init_req(0, x); | |
383 _goto = m.match_tree(x); | |
384 assert(_goto != NULL, ""); | |
385 _goto->set_req(0,_goto); | |
386 | |
387 // Build the CFG in Reverse Post Order | |
388 _num_blocks = build_cfg(); | |
389 _broot = _bbs[_root->_idx]; | |
390 } | |
391 | |
392 //------------------------------build_cfg-------------------------------------- | |
393 // Build a proper looking CFG. Make every block begin with either a StartNode | |
394 // or a RegionNode. Make every block end with either a Goto, If or Return. | |
395 // The RootNode both starts and ends it's own block. Do this with a recursive | |
396 // backwards walk over the control edges. | |
397 uint PhaseCFG::build_cfg() { | |
398 Arena *a = Thread::current()->resource_area(); | |
399 VectorSet visited(a); | |
400 | |
401 // Allocate stack with enough space to avoid frequent realloc | |
402 Node_Stack nstack(a, C->unique() >> 1); | |
403 nstack.push(_root, 0); | |
404 uint sum = 0; // Counter for blocks | |
405 | |
406 while (nstack.is_nonempty()) { | |
407 // node and in's index from stack's top | |
408 // 'np' is _root (see above) or RegionNode, StartNode: we push on stack | |
409 // only nodes which point to the start of basic block (see below). | |
410 Node *np = nstack.node(); | |
411 // idx > 0, except for the first node (_root) pushed on stack | |
412 // at the beginning when idx == 0. | |
413 // We will use the condition (idx == 0) later to end the build. | |
414 uint idx = nstack.index(); | |
415 Node *proj = np->in(idx); | |
416 const Node *x = proj->is_block_proj(); | |
417 // Does the block end with a proper block-ending Node? One of Return, | |
418 // If or Goto? (This check should be done for visited nodes also). | |
419 if (x == NULL) { // Does not end right... | |
420 Node *g = _goto->clone(); // Force it to end in a Goto | |
421 g->set_req(0, proj); | |
422 np->set_req(idx, g); | |
423 x = proj = g; | |
424 } | |
425 if (!visited.test_set(x->_idx)) { // Visit this block once | |
426 // Skip any control-pinned middle'in stuff | |
427 Node *p = proj; | |
428 do { | |
429 proj = p; // Update pointer to last Control | |
430 p = p->in(0); // Move control forward | |
431 } while( !p->is_block_proj() && | |
432 !p->is_block_start() ); | |
433 // Make the block begin with one of Region or StartNode. | |
434 if( !p->is_block_start() ) { | |
435 RegionNode *r = new (C, 2) RegionNode( 2 ); | |
436 r->init_req(1, p); // Insert RegionNode in the way | |
437 proj->set_req(0, r); // Insert RegionNode in the way | |
438 p = r; | |
439 } | |
440 // 'p' now points to the start of this basic block | |
441 | |
442 // Put self in array of basic blocks | |
443 Block *bb = new (_bbs._arena) Block(_bbs._arena,p); | |
444 _bbs.map(p->_idx,bb); | |
445 _bbs.map(x->_idx,bb); | |
3851 | 446 if( x != p ) { // Only for root is x == p |
0 | 447 bb->_nodes.push((Node*)x); |
3851 | 448 } |
0 | 449 // Now handle predecessors |
450 ++sum; // Count 1 for self block | |
451 uint cnt = bb->num_preds(); | |
452 for (int i = (cnt - 1); i > 0; i-- ) { // For all predecessors | |
453 Node *prevproj = p->in(i); // Get prior input | |
454 assert( !prevproj->is_Con(), "dead input not removed" ); | |
455 // Check to see if p->in(i) is a "control-dependent" CFG edge - | |
456 // i.e., it splits at the source (via an IF or SWITCH) and merges | |
457 // at the destination (via a many-input Region). | |
458 // This breaks critical edges. The RegionNode to start the block | |
459 // will be added when <p,i> is pulled off the node stack | |
460 if ( cnt > 2 ) { // Merging many things? | |
461 assert( prevproj== bb->pred(i),""); | |
462 if(prevproj->is_block_proj() != prevproj) { // Control-dependent edge? | |
463 // Force a block on the control-dependent edge | |
464 Node *g = _goto->clone(); // Force it to end in a Goto | |
465 g->set_req(0,prevproj); | |
466 p->set_req(i,g); | |
467 } | |
468 } | |
469 nstack.push(p, i); // 'p' is RegionNode or StartNode | |
470 } | |
471 } else { // Post-processing visited nodes | |
472 nstack.pop(); // remove node from stack | |
473 // Check if it the fist node pushed on stack at the beginning. | |
474 if (idx == 0) break; // end of the build | |
475 // Find predecessor basic block | |
476 Block *pb = _bbs[x->_idx]; | |
477 // Insert into nodes array, if not already there | |
478 if( !_bbs.lookup(proj->_idx) ) { | |
479 assert( x != proj, "" ); | |
480 // Map basic block of projection | |
481 _bbs.map(proj->_idx,pb); | |
482 pb->_nodes.push(proj); | |
483 } | |
484 // Insert self as a child of my predecessor block | |
485 pb->_succs.map(pb->_num_succs++, _bbs[np->_idx]); | |
486 assert( pb->_nodes[ pb->_nodes.size() - pb->_num_succs ]->is_block_proj(), | |
487 "too many control users, not a CFG?" ); | |
488 } | |
489 } | |
490 // Return number of basic blocks for all children and self | |
491 return sum; | |
492 } | |
493 | |
494 //------------------------------insert_goto_at--------------------------------- | |
495 // Inserts a goto & corresponding basic block between | |
496 // block[block_no] and its succ_no'th successor block | |
497 void PhaseCFG::insert_goto_at(uint block_no, uint succ_no) { | |
498 // get block with block_no | |
499 assert(block_no < _num_blocks, "illegal block number"); | |
500 Block* in = _blocks[block_no]; | |
501 // get successor block succ_no | |
502 assert(succ_no < in->_num_succs, "illegal successor number"); | |
503 Block* out = in->_succs[succ_no]; | |
308 | 504 // Compute frequency of the new block. Do this before inserting |
505 // new block in case succ_prob() needs to infer the probability from | |
506 // surrounding blocks. | |
507 float freq = in->_freq * in->succ_prob(succ_no); | |
0 | 508 // get ProjNode corresponding to the succ_no'th successor of the in block |
509 ProjNode* proj = in->_nodes[in->_nodes.size() - in->_num_succs + succ_no]->as_Proj(); | |
510 // create region for basic block | |
511 RegionNode* region = new (C, 2) RegionNode(2); | |
512 region->init_req(1, proj); | |
513 // setup corresponding basic block | |
514 Block* block = new (_bbs._arena) Block(_bbs._arena, region); | |
515 _bbs.map(region->_idx, block); | |
516 C->regalloc()->set_bad(region->_idx); | |
517 // add a goto node | |
518 Node* gto = _goto->clone(); // get a new goto node | |
519 gto->set_req(0, region); | |
520 // add it to the basic block | |
521 block->_nodes.push(gto); | |
522 _bbs.map(gto->_idx, block); | |
523 C->regalloc()->set_bad(gto->_idx); | |
524 // hook up successor block | |
525 block->_succs.map(block->_num_succs++, out); | |
526 // remap successor's predecessors if necessary | |
527 for (uint i = 1; i < out->num_preds(); i++) { | |
528 if (out->pred(i) == proj) out->head()->set_req(i, gto); | |
529 } | |
530 // remap predecessor's successor to new block | |
531 in->_succs.map(succ_no, block); | |
308 | 532 // Set the frequency of the new block |
533 block->_freq = freq; | |
0 | 534 // add new basic block to basic block list |
535 _blocks.insert(block_no + 1, block); | |
536 _num_blocks++; | |
537 } | |
538 | |
539 //------------------------------no_flip_branch--------------------------------- | |
540 // Does this block end in a multiway branch that cannot have the default case | |
541 // flipped for another case? | |
542 static bool no_flip_branch( Block *b ) { | |
543 int branch_idx = b->_nodes.size() - b->_num_succs-1; | |
544 if( branch_idx < 1 ) return false; | |
545 Node *bra = b->_nodes[branch_idx]; | |
418 | 546 if( bra->is_Catch() ) |
547 return true; | |
0 | 548 if( bra->is_Mach() ) { |
418 | 549 if( bra->is_MachNullCheck() ) |
550 return true; | |
0 | 551 int iop = bra->as_Mach()->ideal_Opcode(); |
552 if( iop == Op_FastLock || iop == Op_FastUnlock ) | |
553 return true; | |
554 } | |
555 return false; | |
556 } | |
557 | |
558 //------------------------------convert_NeverBranch_to_Goto-------------------- | |
559 // Check for NeverBranch at block end. This needs to become a GOTO to the | |
560 // true target. NeverBranch are treated as a conditional branch that always | |
561 // goes the same direction for most of the optimizer and are used to give a | |
562 // fake exit path to infinite loops. At this late stage they need to turn | |
563 // into Goto's so that when you enter the infinite loop you indeed hang. | |
564 void PhaseCFG::convert_NeverBranch_to_Goto(Block *b) { | |
565 // Find true target | |
566 int end_idx = b->end_idx(); | |
567 int idx = b->_nodes[end_idx+1]->as_Proj()->_con; | |
568 Block *succ = b->_succs[idx]; | |
569 Node* gto = _goto->clone(); // get a new goto node | |
570 gto->set_req(0, b->head()); | |
571 Node *bp = b->_nodes[end_idx]; | |
572 b->_nodes.map(end_idx,gto); // Slam over NeverBranch | |
573 _bbs.map(gto->_idx, b); | |
574 C->regalloc()->set_bad(gto->_idx); | |
575 b->_nodes.pop(); // Yank projections | |
576 b->_nodes.pop(); // Yank projections | |
577 b->_succs.map(0,succ); // Map only successor | |
578 b->_num_succs = 1; | |
579 // remap successor's predecessors if necessary | |
580 uint j; | |
581 for( j = 1; j < succ->num_preds(); j++) | |
582 if( succ->pred(j)->in(0) == bp ) | |
583 succ->head()->set_req(j, gto); | |
584 // Kill alternate exit path | |
585 Block *dead = b->_succs[1-idx]; | |
586 for( j = 1; j < dead->num_preds(); j++) | |
587 if( dead->pred(j)->in(0) == bp ) | |
588 break; | |
589 // Scan through block, yanking dead path from | |
590 // all regions and phis. | |
591 dead->head()->del_req(j); | |
592 for( int k = 1; dead->_nodes[k]->is_Phi(); k++ ) | |
593 dead->_nodes[k]->del_req(j); | |
594 } | |
595 | |
418 | 596 //------------------------------move_to_next----------------------------------- |
0 | 597 // Helper function to move block bx to the slot following b_index. Return |
598 // true if the move is successful, otherwise false | |
418 | 599 bool PhaseCFG::move_to_next(Block* bx, uint b_index) { |
0 | 600 if (bx == NULL) return false; |
601 | |
602 // Return false if bx is already scheduled. | |
603 uint bx_index = bx->_pre_order; | |
604 if ((bx_index <= b_index) && (_blocks[bx_index] == bx)) { | |
605 return false; | |
606 } | |
607 | |
608 // Find the current index of block bx on the block list | |
609 bx_index = b_index + 1; | |
610 while( bx_index < _num_blocks && _blocks[bx_index] != bx ) bx_index++; | |
611 assert(_blocks[bx_index] == bx, "block not found"); | |
612 | |
613 // If the previous block conditionally falls into bx, return false, | |
614 // because moving bx will create an extra jump. | |
615 for(uint k = 1; k < bx->num_preds(); k++ ) { | |
616 Block* pred = _bbs[bx->pred(k)->_idx]; | |
617 if (pred == _blocks[bx_index-1]) { | |
618 if (pred->_num_succs != 1) { | |
619 return false; | |
620 } | |
621 } | |
622 } | |
623 | |
624 // Reinsert bx just past block 'b' | |
625 _blocks.remove(bx_index); | |
626 _blocks.insert(b_index + 1, bx); | |
627 return true; | |
628 } | |
629 | |
418 | 630 //------------------------------move_to_end------------------------------------ |
0 | 631 // Move empty and uncommon blocks to the end. |
418 | 632 void PhaseCFG::move_to_end(Block *b, uint i) { |
0 | 633 int e = b->is_Empty(); |
634 if (e != Block::not_empty) { | |
635 if (e == Block::empty_with_goto) { | |
636 // Remove the goto, but leave the block. | |
637 b->_nodes.pop(); | |
638 } | |
639 // Mark this block as a connector block, which will cause it to be | |
640 // ignored in certain functions such as non_connector_successor(). | |
641 b->set_connector(); | |
642 } | |
643 // Move the empty block to the end, and don't recheck. | |
644 _blocks.remove(i); | |
645 _blocks.push(b); | |
646 } | |
647 | |
418 | 648 //---------------------------set_loop_alignment-------------------------------- |
649 // Set loop alignment for every block | |
650 void PhaseCFG::set_loop_alignment() { | |
651 uint last = _num_blocks; | |
652 assert( _blocks[0] == _broot, "" ); | |
653 | |
654 for (uint i = 1; i < last; i++ ) { | |
655 Block *b = _blocks[i]; | |
656 if (b->head()->is_Loop()) { | |
657 b->set_loop_alignment(b); | |
658 } | |
659 } | |
660 } | |
661 | |
662 //-----------------------------remove_empty------------------------------------ | |
663 // Make empty basic blocks to be "connector" blocks, Move uncommon blocks | |
664 // to the end. | |
665 void PhaseCFG::remove_empty() { | |
0 | 666 // Move uncommon blocks to the end |
667 uint last = _num_blocks; | |
668 assert( _blocks[0] == _broot, "" ); | |
418 | 669 |
670 for (uint i = 1; i < last; i++) { | |
0 | 671 Block *b = _blocks[i]; |
418 | 672 if (b->is_connector()) break; |
0 | 673 |
674 // Check for NeverBranch at block end. This needs to become a GOTO to the | |
675 // true target. NeverBranch are treated as a conditional branch that | |
676 // always goes the same direction for most of the optimizer and are used | |
677 // to give a fake exit path to infinite loops. At this late stage they | |
678 // need to turn into Goto's so that when you enter the infinite loop you | |
679 // indeed hang. | |
680 if( b->_nodes[b->end_idx()]->Opcode() == Op_NeverBranch ) | |
681 convert_NeverBranch_to_Goto(b); | |
682 | |
683 // Look for uncommon blocks and move to end. | |
418 | 684 if (!C->do_freq_based_layout()) { |
685 if( b->is_uncommon(_bbs) ) { | |
686 move_to_end(b, i); | |
687 last--; // No longer check for being uncommon! | |
688 if( no_flip_branch(b) ) { // Fall-thru case must follow? | |
689 b = _blocks[i]; // Find the fall-thru block | |
690 move_to_end(b, i); | |
691 last--; | |
692 } | |
693 i--; // backup block counter post-increment | |
0 | 694 } |
695 } | |
696 } | |
697 | |
418 | 698 // Move empty blocks to the end |
0 | 699 last = _num_blocks; |
418 | 700 for (uint i = 1; i < last; i++) { |
0 | 701 Block *b = _blocks[i]; |
418 | 702 if (b->is_Empty() != Block::not_empty) { |
703 move_to_end(b, i); | |
704 last--; | |
705 i--; | |
0 | 706 } |
707 } // End of for all blocks | |
418 | 708 } |
0 | 709 |
418 | 710 //-----------------------------fixup_flow-------------------------------------- |
711 // Fix up the final control flow for basic blocks. | |
712 void PhaseCFG::fixup_flow() { | |
0 | 713 // Fixup final control flow for the blocks. Remove jump-to-next |
714 // block. If neither arm of a IF follows the conditional branch, we | |
715 // have to add a second jump after the conditional. We place the | |
716 // TRUE branch target in succs[0] for both GOTOs and IFs. | |
418 | 717 for (uint i=0; i < _num_blocks; i++) { |
0 | 718 Block *b = _blocks[i]; |
719 b->_pre_order = i; // turn pre-order into block-index | |
720 | |
721 // Connector blocks need no further processing. | |
722 if (b->is_connector()) { | |
723 assert((i+1) == _num_blocks || _blocks[i+1]->is_connector(), | |
724 "All connector blocks should sink to the end"); | |
725 continue; | |
726 } | |
727 assert(b->is_Empty() != Block::completely_empty, | |
728 "Empty blocks should be connectors"); | |
729 | |
730 Block *bnext = (i < _num_blocks-1) ? _blocks[i+1] : NULL; | |
731 Block *bs0 = b->non_connector_successor(0); | |
732 | |
733 // Check for multi-way branches where I cannot negate the test to | |
734 // exchange the true and false targets. | |
735 if( no_flip_branch( b ) ) { | |
736 // Find fall through case - if must fall into its target | |
737 int branch_idx = b->_nodes.size() - b->_num_succs; | |
738 for (uint j2 = 0; j2 < b->_num_succs; j2++) { | |
739 const ProjNode* p = b->_nodes[branch_idx + j2]->as_Proj(); | |
740 if (p->_con == 0) { | |
741 // successor j2 is fall through case | |
742 if (b->non_connector_successor(j2) != bnext) { | |
743 // but it is not the next block => insert a goto | |
744 insert_goto_at(i, j2); | |
745 } | |
746 // Put taken branch in slot 0 | |
747 if( j2 == 0 && b->_num_succs == 2) { | |
748 // Flip targets in succs map | |
749 Block *tbs0 = b->_succs[0]; | |
750 Block *tbs1 = b->_succs[1]; | |
751 b->_succs.map( 0, tbs1 ); | |
752 b->_succs.map( 1, tbs0 ); | |
753 } | |
754 break; | |
755 } | |
756 } | |
757 // Remove all CatchProjs | |
418 | 758 for (uint j1 = 0; j1 < b->_num_succs; j1++) b->_nodes.pop(); |
0 | 759 |
760 } else if (b->_num_succs == 1) { | |
761 // Block ends in a Goto? | |
762 if (bnext == bs0) { | |
763 // We fall into next block; remove the Goto | |
764 b->_nodes.pop(); | |
765 } | |
766 | |
767 } else if( b->_num_succs == 2 ) { // Block ends in a If? | |
768 // Get opcode of 1st projection (matches _succs[0]) | |
769 // Note: Since this basic block has 2 exits, the last 2 nodes must | |
770 // be projections (in any order), the 3rd last node must be | |
771 // the IfNode (we have excluded other 2-way exits such as | |
772 // CatchNodes already). | |
773 MachNode *iff = b->_nodes[b->_nodes.size()-3]->as_Mach(); | |
774 ProjNode *proj0 = b->_nodes[b->_nodes.size()-2]->as_Proj(); | |
775 ProjNode *proj1 = b->_nodes[b->_nodes.size()-1]->as_Proj(); | |
776 | |
777 // Assert that proj0 and succs[0] match up. Similarly for proj1 and succs[1]. | |
778 assert(proj0->raw_out(0) == b->_succs[0]->head(), "Mismatch successor 0"); | |
779 assert(proj1->raw_out(0) == b->_succs[1]->head(), "Mismatch successor 1"); | |
780 | |
781 Block *bs1 = b->non_connector_successor(1); | |
782 | |
783 // Check for neither successor block following the current | |
784 // block ending in a conditional. If so, move one of the | |
785 // successors after the current one, provided that the | |
786 // successor was previously unscheduled, but moveable | |
787 // (i.e., all paths to it involve a branch). | |
418 | 788 if( !C->do_freq_based_layout() && bnext != bs0 && bnext != bs1 ) { |
0 | 789 // Choose the more common successor based on the probability |
790 // of the conditional branch. | |
791 Block *bx = bs0; | |
792 Block *by = bs1; | |
793 | |
794 // _prob is the probability of taking the true path. Make | |
795 // p the probability of taking successor #1. | |
796 float p = iff->as_MachIf()->_prob; | |
797 if( proj0->Opcode() == Op_IfTrue ) { | |
798 p = 1.0 - p; | |
799 } | |
800 | |
801 // Prefer successor #1 if p > 0.5 | |
802 if (p > PROB_FAIR) { | |
803 bx = bs1; | |
804 by = bs0; | |
805 } | |
806 | |
807 // Attempt the more common successor first | |
418 | 808 if (move_to_next(bx, i)) { |
0 | 809 bnext = bx; |
418 | 810 } else if (move_to_next(by, i)) { |
0 | 811 bnext = by; |
812 } | |
813 } | |
814 | |
815 // Check for conditional branching the wrong way. Negate | |
816 // conditional, if needed, so it falls into the following block | |
817 // and branches to the not-following block. | |
818 | |
819 // Check for the next block being in succs[0]. We are going to branch | |
820 // to succs[0], so we want the fall-thru case as the next block in | |
821 // succs[1]. | |
822 if (bnext == bs0) { | |
823 // Fall-thru case in succs[0], so flip targets in succs map | |
824 Block *tbs0 = b->_succs[0]; | |
825 Block *tbs1 = b->_succs[1]; | |
826 b->_succs.map( 0, tbs1 ); | |
827 b->_succs.map( 1, tbs0 ); | |
828 // Flip projection for each target | |
829 { ProjNode *tmp = proj0; proj0 = proj1; proj1 = tmp; } | |
830 | |
418 | 831 } else if( bnext != bs1 ) { |
832 // Need a double-branch | |
0 | 833 // The existing conditional branch need not change. |
834 // Add a unconditional branch to the false target. | |
835 // Alas, it must appear in its own block and adding a | |
836 // block this late in the game is complicated. Sigh. | |
837 insert_goto_at(i, 1); | |
838 } | |
839 | |
840 // Make sure we TRUE branch to the target | |
418 | 841 if( proj0->Opcode() == Op_IfFalse ) { |
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842 iff->as_MachIf()->negate(); |
418 | 843 } |
0 | 844 |
845 b->_nodes.pop(); // Remove IfFalse & IfTrue projections | |
846 b->_nodes.pop(); | |
847 | |
848 } else { | |
849 // Multi-exit block, e.g. a switch statement | |
850 // But we don't need to do anything here | |
851 } | |
852 } // End of for all blocks | |
853 } | |
854 | |
855 | |
856 //------------------------------dump------------------------------------------- | |
857 #ifndef PRODUCT | |
858 void PhaseCFG::_dump_cfg( const Node *end, VectorSet &visited ) const { | |
859 const Node *x = end->is_block_proj(); | |
860 assert( x, "not a CFG" ); | |
861 | |
862 // Do not visit this block again | |
863 if( visited.test_set(x->_idx) ) return; | |
864 | |
865 // Skip through this block | |
866 const Node *p = x; | |
867 do { | |
868 p = p->in(0); // Move control forward | |
869 assert( !p->is_block_proj() || p->is_Root(), "not a CFG" ); | |
870 } while( !p->is_block_start() ); | |
871 | |
872 // Recursively visit | |
873 for( uint i=1; i<p->req(); i++ ) | |
874 _dump_cfg(p->in(i),visited); | |
875 | |
876 // Dump the block | |
877 _bbs[p->_idx]->dump(&_bbs); | |
878 } | |
879 | |
880 void PhaseCFG::dump( ) const { | |
881 tty->print("\n--- CFG --- %d BBs\n",_num_blocks); | |
882 if( _blocks.size() ) { // Did we do basic-block layout? | |
883 for( uint i=0; i<_num_blocks; i++ ) | |
884 _blocks[i]->dump(&_bbs); | |
885 } else { // Else do it with a DFS | |
886 VectorSet visited(_bbs._arena); | |
887 _dump_cfg(_root,visited); | |
888 } | |
889 } | |
890 | |
891 void PhaseCFG::dump_headers() { | |
892 for( uint i = 0; i < _num_blocks; i++ ) { | |
893 if( _blocks[i] == NULL ) continue; | |
894 _blocks[i]->dump_head(&_bbs); | |
895 } | |
896 } | |
897 | |
898 void PhaseCFG::verify( ) const { | |
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899 #ifdef ASSERT |
0 | 900 // Verify sane CFG |
901 for( uint i = 0; i < _num_blocks; i++ ) { | |
902 Block *b = _blocks[i]; | |
903 uint cnt = b->_nodes.size(); | |
904 uint j; | |
905 for( j = 0; j < cnt; j++ ) { | |
906 Node *n = b->_nodes[j]; | |
907 assert( _bbs[n->_idx] == b, "" ); | |
908 if( j >= 1 && n->is_Mach() && | |
909 n->as_Mach()->ideal_Opcode() == Op_CreateEx ) { | |
910 assert( j == 1 || b->_nodes[j-1]->is_Phi(), | |
911 "CreateEx must be first instruction in block" ); | |
912 } | |
913 for( uint k = 0; k < n->req(); k++ ) { | |
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914 Node *def = n->in(k); |
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915 if( def && def != n ) { |
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916 assert( _bbs[def->_idx] || def->is_Con(), |
0 | 917 "must have block; constants for debug info ok" ); |
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918 // Verify that instructions in the block is in correct order. |
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919 // Uses must follow their definition if they are at the same block. |
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920 // Mostly done to check that MachSpillCopy nodes are placed correctly |
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921 // when CreateEx node is moved in build_ifg_physical(). |
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922 if( _bbs[def->_idx] == b && |
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923 !(b->head()->is_Loop() && n->is_Phi()) && |
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924 // See (+++) comment in reg_split.cpp |
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925 !(n->jvms() != NULL && n->jvms()->is_monitor_use(k)) ) { |
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926 bool is_loop = false; |
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927 if (n->is_Phi()) { |
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928 for( uint l = 1; l < def->req(); l++ ) { |
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929 if (n == def->in(l)) { |
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930 is_loop = true; |
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931 break; // Some kind of loop |
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932 } |
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933 } |
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934 } |
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935 assert( is_loop || b->find_node(def) < j, "uses must follow definitions" ); |
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936 } |
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937 if( def->is_SafePointScalarObject() ) { |
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938 assert(_bbs[def->_idx] == b, "SafePointScalarObject Node should be at the same block as its SafePoint node"); |
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939 assert(_bbs[def->_idx] == _bbs[def->in(0)->_idx], "SafePointScalarObject Node should be at the same block as its control edge"); |
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940 } |
0 | 941 } |
942 } | |
943 } | |
944 | |
945 j = b->end_idx(); | |
946 Node *bp = (Node*)b->_nodes[b->_nodes.size()-1]->is_block_proj(); | |
947 assert( bp, "last instruction must be a block proj" ); | |
948 assert( bp == b->_nodes[j], "wrong number of successors for this block" ); | |
949 if( bp->is_Catch() ) { | |
3842 | 950 while( b->_nodes[--j]->is_MachProj() ) ; |
951 assert( b->_nodes[j]->is_MachCall(), "CatchProj must follow call" ); | |
0 | 952 } |
953 else if( bp->is_Mach() && bp->as_Mach()->ideal_Opcode() == Op_If ) { | |
954 assert( b->_num_succs == 2, "Conditional branch must have two targets"); | |
955 } | |
956 } | |
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957 #endif |
0 | 958 } |
959 #endif | |
960 | |
961 //============================================================================= | |
962 //------------------------------UnionFind-------------------------------------- | |
963 UnionFind::UnionFind( uint max ) : _cnt(max), _max(max), _indices(NEW_RESOURCE_ARRAY(uint,max)) { | |
964 Copy::zero_to_bytes( _indices, sizeof(uint)*max ); | |
965 } | |
966 | |
967 void UnionFind::extend( uint from_idx, uint to_idx ) { | |
968 _nesting.check(); | |
969 if( from_idx >= _max ) { | |
970 uint size = 16; | |
971 while( size <= from_idx ) size <<=1; | |
972 _indices = REALLOC_RESOURCE_ARRAY( uint, _indices, _max, size ); | |
973 _max = size; | |
974 } | |
975 while( _cnt <= from_idx ) _indices[_cnt++] = 0; | |
976 _indices[from_idx] = to_idx; | |
977 } | |
978 | |
979 void UnionFind::reset( uint max ) { | |
980 assert( max <= max_uint, "Must fit within uint" ); | |
981 // Force the Union-Find mapping to be at least this large | |
982 extend(max,0); | |
983 // Initialize to be the ID mapping. | |
418 | 984 for( uint i=0; i<max; i++ ) map(i,i); |
0 | 985 } |
986 | |
987 //------------------------------Find_compress---------------------------------- | |
988 // Straight out of Tarjan's union-find algorithm | |
989 uint UnionFind::Find_compress( uint idx ) { | |
990 uint cur = idx; | |
991 uint next = lookup(cur); | |
992 while( next != cur ) { // Scan chain of equivalences | |
993 assert( next < cur, "always union smaller" ); | |
994 cur = next; // until find a fixed-point | |
995 next = lookup(cur); | |
996 } | |
997 // Core of union-find algorithm: update chain of | |
998 // equivalences to be equal to the root. | |
999 while( idx != next ) { | |
1000 uint tmp = lookup(idx); | |
1001 map(idx, next); | |
1002 idx = tmp; | |
1003 } | |
1004 return idx; | |
1005 } | |
1006 | |
1007 //------------------------------Find_const------------------------------------- | |
1008 // Like Find above, but no path compress, so bad asymptotic behavior | |
1009 uint UnionFind::Find_const( uint idx ) const { | |
1010 if( idx == 0 ) return idx; // Ignore the zero idx | |
1011 // Off the end? This can happen during debugging dumps | |
1012 // when data structures have not finished being updated. | |
1013 if( idx >= _max ) return idx; | |
1014 uint next = lookup(idx); | |
1015 while( next != idx ) { // Scan chain of equivalences | |
1016 idx = next; // until find a fixed-point | |
1017 next = lookup(idx); | |
1018 } | |
1019 return next; | |
1020 } | |
1021 | |
1022 //------------------------------Union------------------------------------------ | |
1023 // union 2 sets together. | |
1024 void UnionFind::Union( uint idx1, uint idx2 ) { | |
1025 uint src = Find(idx1); | |
1026 uint dst = Find(idx2); | |
1027 assert( src, "" ); | |
1028 assert( dst, "" ); | |
1029 assert( src < _max, "oob" ); | |
1030 assert( dst < _max, "oob" ); | |
1031 assert( src < dst, "always union smaller" ); | |
1032 map(dst,src); | |
1033 } | |
418 | 1034 |
1035 #ifndef PRODUCT | |
1036 static void edge_dump(GrowableArray<CFGEdge *> *edges) { | |
1037 tty->print_cr("---- Edges ----"); | |
1038 for (int i = 0; i < edges->length(); i++) { | |
1039 CFGEdge *e = edges->at(i); | |
1040 if (e != NULL) { | |
1041 edges->at(i)->dump(); | |
1042 } | |
1043 } | |
1044 } | |
1045 | |
1046 static void trace_dump(Trace *traces[], int count) { | |
1047 tty->print_cr("---- Traces ----"); | |
1048 for (int i = 0; i < count; i++) { | |
1049 Trace *tr = traces[i]; | |
1050 if (tr != NULL) { | |
1051 tr->dump(); | |
1052 } | |
1053 } | |
1054 } | |
1055 | |
1056 void Trace::dump( ) const { | |
1057 tty->print_cr("Trace (freq %f)", first_block()->_freq); | |
1058 for (Block *b = first_block(); b != NULL; b = next(b)) { | |
1059 tty->print(" B%d", b->_pre_order); | |
1060 if (b->head()->is_Loop()) { | |
1061 tty->print(" (L%d)", b->compute_loop_alignment()); | |
1062 } | |
1063 if (b->has_loop_alignment()) { | |
1064 tty->print(" (T%d)", b->code_alignment()); | |
1065 } | |
1066 } | |
1067 tty->cr(); | |
1068 } | |
1069 | |
1070 void CFGEdge::dump( ) const { | |
1071 tty->print(" B%d --> B%d Freq: %f out:%3d%% in:%3d%% State: ", | |
1072 from()->_pre_order, to()->_pre_order, freq(), _from_pct, _to_pct); | |
1073 switch(state()) { | |
1074 case connected: | |
1075 tty->print("connected"); | |
1076 break; | |
1077 case open: | |
1078 tty->print("open"); | |
1079 break; | |
1080 case interior: | |
1081 tty->print("interior"); | |
1082 break; | |
1083 } | |
1084 if (infrequent()) { | |
1085 tty->print(" infrequent"); | |
1086 } | |
1087 tty->cr(); | |
1088 } | |
1089 #endif | |
1090 | |
1091 //============================================================================= | |
1092 | |
1093 //------------------------------edge_order------------------------------------- | |
1094 // Comparison function for edges | |
1095 static int edge_order(CFGEdge **e0, CFGEdge **e1) { | |
1096 float freq0 = (*e0)->freq(); | |
1097 float freq1 = (*e1)->freq(); | |
1098 if (freq0 != freq1) { | |
1099 return freq0 > freq1 ? -1 : 1; | |
1100 } | |
1101 | |
1102 int dist0 = (*e0)->to()->_rpo - (*e0)->from()->_rpo; | |
1103 int dist1 = (*e1)->to()->_rpo - (*e1)->from()->_rpo; | |
1104 | |
1105 return dist1 - dist0; | |
1106 } | |
1107 | |
1108 //------------------------------trace_frequency_order-------------------------- | |
1109 // Comparison function for edges | |
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1110 extern "C" int trace_frequency_order(const void *p0, const void *p1) { |
418 | 1111 Trace *tr0 = *(Trace **) p0; |
1112 Trace *tr1 = *(Trace **) p1; | |
1113 Block *b0 = tr0->first_block(); | |
1114 Block *b1 = tr1->first_block(); | |
1115 | |
1116 // The trace of connector blocks goes at the end; | |
1117 // we only expect one such trace | |
1118 if (b0->is_connector() != b1->is_connector()) { | |
1119 return b1->is_connector() ? -1 : 1; | |
1120 } | |
1121 | |
1122 // Pull more frequently executed blocks to the beginning | |
1123 float freq0 = b0->_freq; | |
1124 float freq1 = b1->_freq; | |
1125 if (freq0 != freq1) { | |
1126 return freq0 > freq1 ? -1 : 1; | |
1127 } | |
1128 | |
1129 int diff = tr0->first_block()->_rpo - tr1->first_block()->_rpo; | |
1130 | |
1131 return diff; | |
1132 } | |
1133 | |
1134 //------------------------------find_edges------------------------------------- | |
1135 // Find edges of interest, i.e, those which can fall through. Presumes that | |
1136 // edges which don't fall through are of low frequency and can be generally | |
1137 // ignored. Initialize the list of traces. | |
1138 void PhaseBlockLayout::find_edges() | |
1139 { | |
1140 // Walk the blocks, creating edges and Traces | |
1141 uint i; | |
1142 Trace *tr = NULL; | |
1143 for (i = 0; i < _cfg._num_blocks; i++) { | |
1144 Block *b = _cfg._blocks[i]; | |
1145 tr = new Trace(b, next, prev); | |
1146 traces[tr->id()] = tr; | |
1147 | |
1148 // All connector blocks should be at the end of the list | |
1149 if (b->is_connector()) break; | |
1150 | |
1151 // If this block and the next one have a one-to-one successor | |
1152 // predecessor relationship, simply append the next block | |
1153 int nfallthru = b->num_fall_throughs(); | |
1154 while (nfallthru == 1 && | |
1155 b->succ_fall_through(0)) { | |
1156 Block *n = b->_succs[0]; | |
1157 | |
1158 // Skip over single-entry connector blocks, we don't want to | |
1159 // add them to the trace. | |
1160 while (n->is_connector() && n->num_preds() == 1) { | |
1161 n = n->_succs[0]; | |
1162 } | |
1163 | |
1164 // We see a merge point, so stop search for the next block | |
1165 if (n->num_preds() != 1) break; | |
1166 | |
1167 i++; | |
1168 assert(n = _cfg._blocks[i], "expecting next block"); | |
1169 tr->append(n); | |
1170 uf->map(n->_pre_order, tr->id()); | |
1171 traces[n->_pre_order] = NULL; | |
1172 nfallthru = b->num_fall_throughs(); | |
1173 b = n; | |
1174 } | |
1175 | |
1176 if (nfallthru > 0) { | |
1177 // Create a CFGEdge for each outgoing | |
1178 // edge that could be a fall-through. | |
1179 for (uint j = 0; j < b->_num_succs; j++ ) { | |
1180 if (b->succ_fall_through(j)) { | |
1181 Block *target = b->non_connector_successor(j); | |
1182 float freq = b->_freq * b->succ_prob(j); | |
1183 int from_pct = (int) ((100 * freq) / b->_freq); | |
1184 int to_pct = (int) ((100 * freq) / target->_freq); | |
1185 edges->append(new CFGEdge(b, target, freq, from_pct, to_pct)); | |
1186 } | |
1187 } | |
1188 } | |
1189 } | |
1190 | |
1191 // Group connector blocks into one trace | |
1192 for (i++; i < _cfg._num_blocks; i++) { | |
1193 Block *b = _cfg._blocks[i]; | |
1194 assert(b->is_connector(), "connector blocks at the end"); | |
1195 tr->append(b); | |
1196 uf->map(b->_pre_order, tr->id()); | |
1197 traces[b->_pre_order] = NULL; | |
1198 } | |
1199 } | |
1200 | |
1201 //------------------------------union_traces---------------------------------- | |
1202 // Union two traces together in uf, and null out the trace in the list | |
1203 void PhaseBlockLayout::union_traces(Trace* updated_trace, Trace* old_trace) | |
1204 { | |
1205 uint old_id = old_trace->id(); | |
1206 uint updated_id = updated_trace->id(); | |
1207 | |
1208 uint lo_id = updated_id; | |
1209 uint hi_id = old_id; | |
1210 | |
1211 // If from is greater than to, swap values to meet | |
1212 // UnionFind guarantee. | |
1213 if (updated_id > old_id) { | |
1214 lo_id = old_id; | |
1215 hi_id = updated_id; | |
1216 | |
1217 // Fix up the trace ids | |
1218 traces[lo_id] = traces[updated_id]; | |
1219 updated_trace->set_id(lo_id); | |
1220 } | |
1221 | |
1222 // Union the lower with the higher and remove the pointer | |
1223 // to the higher. | |
1224 uf->Union(lo_id, hi_id); | |
1225 traces[hi_id] = NULL; | |
1226 } | |
1227 | |
1228 //------------------------------grow_traces------------------------------------- | |
1229 // Append traces together via the most frequently executed edges | |
1230 void PhaseBlockLayout::grow_traces() | |
1231 { | |
1232 // Order the edges, and drive the growth of Traces via the most | |
1233 // frequently executed edges. | |
1234 edges->sort(edge_order); | |
1235 for (int i = 0; i < edges->length(); i++) { | |
1236 CFGEdge *e = edges->at(i); | |
1237 | |
1238 if (e->state() != CFGEdge::open) continue; | |
1239 | |
1240 Block *src_block = e->from(); | |
1241 Block *targ_block = e->to(); | |
1242 | |
1243 // Don't grow traces along backedges? | |
1244 if (!BlockLayoutRotateLoops) { | |
1245 if (targ_block->_rpo <= src_block->_rpo) { | |
1246 targ_block->set_loop_alignment(targ_block); | |
1247 continue; | |
1248 } | |
1249 } | |
1250 | |
1251 Trace *src_trace = trace(src_block); | |
1252 Trace *targ_trace = trace(targ_block); | |
1253 | |
1254 // If the edge in question can join two traces at their ends, | |
1255 // append one trace to the other. | |
1256 if (src_trace->last_block() == src_block) { | |
1257 if (src_trace == targ_trace) { | |
1258 e->set_state(CFGEdge::interior); | |
1259 if (targ_trace->backedge(e)) { | |
1260 // Reset i to catch any newly eligible edge | |
1261 // (Or we could remember the first "open" edge, and reset there) | |
1262 i = 0; | |
1263 } | |
1264 } else if (targ_trace->first_block() == targ_block) { | |
1265 e->set_state(CFGEdge::connected); | |
1266 src_trace->append(targ_trace); | |
1267 union_traces(src_trace, targ_trace); | |
1268 } | |
1269 } | |
1270 } | |
1271 } | |
1272 | |
1273 //------------------------------merge_traces----------------------------------- | |
1274 // Embed one trace into another, if the fork or join points are sufficiently | |
1275 // balanced. | |
1276 void PhaseBlockLayout::merge_traces(bool fall_thru_only) | |
1277 { | |
1278 // Walk the edge list a another time, looking at unprocessed edges. | |
1279 // Fold in diamonds | |
1280 for (int i = 0; i < edges->length(); i++) { | |
1281 CFGEdge *e = edges->at(i); | |
1282 | |
1283 if (e->state() != CFGEdge::open) continue; | |
1284 if (fall_thru_only) { | |
1285 if (e->infrequent()) continue; | |
1286 } | |
1287 | |
1288 Block *src_block = e->from(); | |
1289 Trace *src_trace = trace(src_block); | |
1290 bool src_at_tail = src_trace->last_block() == src_block; | |
1291 | |
1292 Block *targ_block = e->to(); | |
1293 Trace *targ_trace = trace(targ_block); | |
1294 bool targ_at_start = targ_trace->first_block() == targ_block; | |
1295 | |
1296 if (src_trace == targ_trace) { | |
1297 // This may be a loop, but we can't do much about it. | |
1298 e->set_state(CFGEdge::interior); | |
1299 continue; | |
1300 } | |
1301 | |
1302 if (fall_thru_only) { | |
1303 // If the edge links the middle of two traces, we can't do anything. | |
1304 // Mark the edge and continue. | |
1305 if (!src_at_tail & !targ_at_start) { | |
1306 continue; | |
1307 } | |
1308 | |
1309 // Don't grow traces along backedges? | |
1310 if (!BlockLayoutRotateLoops && (targ_block->_rpo <= src_block->_rpo)) { | |
1311 continue; | |
1312 } | |
1313 | |
1314 // If both ends of the edge are available, why didn't we handle it earlier? | |
1315 assert(src_at_tail ^ targ_at_start, "Should have caught this edge earlier."); | |
1316 | |
1317 if (targ_at_start) { | |
1318 // Insert the "targ" trace in the "src" trace if the insertion point | |
1319 // is a two way branch. | |
1320 // Better profitability check possible, but may not be worth it. | |
1321 // Someday, see if the this "fork" has an associated "join"; | |
1322 // then make a policy on merging this trace at the fork or join. | |
1323 // For example, other things being equal, it may be better to place this | |
1324 // trace at the join point if the "src" trace ends in a two-way, but | |
1325 // the insertion point is one-way. | |
1326 assert(src_block->num_fall_throughs() == 2, "unexpected diamond"); | |
1327 e->set_state(CFGEdge::connected); | |
1328 src_trace->insert_after(src_block, targ_trace); | |
1329 union_traces(src_trace, targ_trace); | |
1330 } else if (src_at_tail) { | |
1331 if (src_trace != trace(_cfg._broot)) { | |
1332 e->set_state(CFGEdge::connected); | |
1333 targ_trace->insert_before(targ_block, src_trace); | |
1334 union_traces(targ_trace, src_trace); | |
1335 } | |
1336 } | |
1337 } else if (e->state() == CFGEdge::open) { | |
1338 // Append traces, even without a fall-thru connection. | |
605 | 1339 // But leave root entry at the beginning of the block list. |
418 | 1340 if (targ_trace != trace(_cfg._broot)) { |
1341 e->set_state(CFGEdge::connected); | |
1342 src_trace->append(targ_trace); | |
1343 union_traces(src_trace, targ_trace); | |
1344 } | |
1345 } | |
1346 } | |
1347 } | |
1348 | |
1349 //----------------------------reorder_traces----------------------------------- | |
1350 // Order the sequence of the traces in some desirable way, and fixup the | |
1351 // jumps at the end of each block. | |
1352 void PhaseBlockLayout::reorder_traces(int count) | |
1353 { | |
1354 ResourceArea *area = Thread::current()->resource_area(); | |
1355 Trace ** new_traces = NEW_ARENA_ARRAY(area, Trace *, count); | |
1356 Block_List worklist; | |
1357 int new_count = 0; | |
1358 | |
1359 // Compact the traces. | |
1360 for (int i = 0; i < count; i++) { | |
1361 Trace *tr = traces[i]; | |
1362 if (tr != NULL) { | |
1363 new_traces[new_count++] = tr; | |
1364 } | |
1365 } | |
1366 | |
1367 // The entry block should be first on the new trace list. | |
1368 Trace *tr = trace(_cfg._broot); | |
1369 assert(tr == new_traces[0], "entry trace misplaced"); | |
1370 | |
1371 // Sort the new trace list by frequency | |
1372 qsort(new_traces + 1, new_count - 1, sizeof(new_traces[0]), trace_frequency_order); | |
1373 | |
1374 // Patch up the successor blocks | |
1375 _cfg._blocks.reset(); | |
1376 _cfg._num_blocks = 0; | |
1377 for (int i = 0; i < new_count; i++) { | |
1378 Trace *tr = new_traces[i]; | |
1379 if (tr != NULL) { | |
1380 tr->fixup_blocks(_cfg); | |
1381 } | |
1382 } | |
1383 } | |
1384 | |
1385 //------------------------------PhaseBlockLayout------------------------------- | |
1386 // Order basic blocks based on frequency | |
1387 PhaseBlockLayout::PhaseBlockLayout(PhaseCFG &cfg) : | |
1388 Phase(BlockLayout), | |
1389 _cfg(cfg) | |
1390 { | |
1391 ResourceMark rm; | |
1392 ResourceArea *area = Thread::current()->resource_area(); | |
1393 | |
1394 // List of traces | |
1395 int size = _cfg._num_blocks + 1; | |
1396 traces = NEW_ARENA_ARRAY(area, Trace *, size); | |
1397 memset(traces, 0, size*sizeof(Trace*)); | |
1398 next = NEW_ARENA_ARRAY(area, Block *, size); | |
1399 memset(next, 0, size*sizeof(Block *)); | |
1400 prev = NEW_ARENA_ARRAY(area, Block *, size); | |
1401 memset(prev , 0, size*sizeof(Block *)); | |
1402 | |
1403 // List of edges | |
1404 edges = new GrowableArray<CFGEdge*>; | |
1405 | |
1406 // Mapping block index --> block_trace | |
1407 uf = new UnionFind(size); | |
1408 uf->reset(size); | |
1409 | |
1410 // Find edges and create traces. | |
1411 find_edges(); | |
1412 | |
1413 // Grow traces at their ends via most frequent edges. | |
1414 grow_traces(); | |
1415 | |
1416 // Merge one trace into another, but only at fall-through points. | |
1417 // This may make diamonds and other related shapes in a trace. | |
1418 merge_traces(true); | |
1419 | |
1420 // Run merge again, allowing two traces to be catenated, even if | |
1421 // one does not fall through into the other. This appends loosely | |
1422 // related traces to be near each other. | |
1423 merge_traces(false); | |
1424 | |
1425 // Re-order all the remaining traces by frequency | |
1426 reorder_traces(size); | |
1427 | |
1428 assert(_cfg._num_blocks >= (uint) (size - 1), "number of blocks can not shrink"); | |
1429 } | |
1430 | |
1431 | |
1432 //------------------------------backedge--------------------------------------- | |
1433 // Edge e completes a loop in a trace. If the target block is head of the | |
1434 // loop, rotate the loop block so that the loop ends in a conditional branch. | |
1435 bool Trace::backedge(CFGEdge *e) { | |
1436 bool loop_rotated = false; | |
1437 Block *src_block = e->from(); | |
1438 Block *targ_block = e->to(); | |
1439 | |
1440 assert(last_block() == src_block, "loop discovery at back branch"); | |
1441 if (first_block() == targ_block) { | |
1442 if (BlockLayoutRotateLoops && last_block()->num_fall_throughs() < 2) { | |
1443 // Find the last block in the trace that has a conditional | |
1444 // branch. | |
1445 Block *b; | |
1446 for (b = last_block(); b != NULL; b = prev(b)) { | |
1447 if (b->num_fall_throughs() == 2) { | |
1448 break; | |
1449 } | |
1450 } | |
1451 | |
1452 if (b != last_block() && b != NULL) { | |
1453 loop_rotated = true; | |
1454 | |
1455 // Rotate the loop by doing two-part linked-list surgery. | |
1456 append(first_block()); | |
1457 break_loop_after(b); | |
1458 } | |
1459 } | |
1460 | |
1461 // Backbranch to the top of a trace | |
605 | 1462 // Scroll forward through the trace from the targ_block. If we find |
418 | 1463 // a loop head before another loop top, use the the loop head alignment. |
1464 for (Block *b = targ_block; b != NULL; b = next(b)) { | |
1465 if (b->has_loop_alignment()) { | |
1466 break; | |
1467 } | |
1468 if (b->head()->is_Loop()) { | |
1469 targ_block = b; | |
1470 break; | |
1471 } | |
1472 } | |
1473 | |
1474 first_block()->set_loop_alignment(targ_block); | |
1475 | |
1476 } else { | |
1477 // Backbranch into the middle of a trace | |
1478 targ_block->set_loop_alignment(targ_block); | |
1479 } | |
1480 | |
1481 return loop_rotated; | |
1482 } | |
1483 | |
1484 //------------------------------fixup_blocks----------------------------------- | |
1485 // push blocks onto the CFG list | |
1486 // ensure that blocks have the correct two-way branch sense | |
1487 void Trace::fixup_blocks(PhaseCFG &cfg) { | |
1488 Block *last = last_block(); | |
1489 for (Block *b = first_block(); b != NULL; b = next(b)) { | |
1490 cfg._blocks.push(b); | |
1491 cfg._num_blocks++; | |
1492 if (!b->is_connector()) { | |
1493 int nfallthru = b->num_fall_throughs(); | |
1494 if (b != last) { | |
1495 if (nfallthru == 2) { | |
1496 // Ensure that the sense of the branch is correct | |
1497 Block *bnext = next(b); | |
1498 Block *bs0 = b->non_connector_successor(0); | |
1499 | |
1500 MachNode *iff = b->_nodes[b->_nodes.size()-3]->as_Mach(); | |
1501 ProjNode *proj0 = b->_nodes[b->_nodes.size()-2]->as_Proj(); | |
1502 ProjNode *proj1 = b->_nodes[b->_nodes.size()-1]->as_Proj(); | |
1503 | |
1504 if (bnext == bs0) { | |
1505 // Fall-thru case in succs[0], should be in succs[1] | |
1506 | |
1507 // Flip targets in _succs map | |
1508 Block *tbs0 = b->_succs[0]; | |
1509 Block *tbs1 = b->_succs[1]; | |
1510 b->_succs.map( 0, tbs1 ); | |
1511 b->_succs.map( 1, tbs0 ); | |
1512 | |
1513 // Flip projections to match targets | |
1514 b->_nodes.map(b->_nodes.size()-2, proj1); | |
1515 b->_nodes.map(b->_nodes.size()-1, proj0); | |
1516 } | |
1517 } | |
1518 } | |
1519 } | |
1520 } | |
1521 } |