1 /*
2 * Copyright (c) 1997, 2009, Oracle and/or its affiliates. All rights reserved.
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 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "incls/_precompiled.incl"
26 #include "incls/_live.cpp.incl"
27
28
29
30 //=============================================================================
31 //------------------------------PhaseLive--------------------------------------
32 // Compute live-in/live-out. We use a totally incremental algorithm. The LIVE
33 // problem is monotonic. The steady-state solution looks like this: pull a
34 // block from the worklist. It has a set of delta's - values which are newly
35 // live-in from the block. Push these to the live-out sets of all predecessor
36 // blocks. At each predecessor, the new live-out values are ANDed with what is
37 // already live-out (extra stuff is added to the live-out sets). Then the
38 // remaining new live-out values are ANDed with what is locally defined.
39 // Leftover bits become the new live-in for the predecessor block, and the pred
40 // block is put on the worklist.
41 // The locally live-in stuff is computed once and added to predecessor
42 // live-out sets. This separate compilation is done in the outer loop below.
43 PhaseLive::PhaseLive( const PhaseCFG &cfg, LRG_List &names, Arena *arena ) : Phase(LIVE), _cfg(cfg), _names(names), _arena(arena), _live(0) {
44 }
45
46 void PhaseLive::compute(uint maxlrg) {
47 _maxlrg = maxlrg;
48 _worklist = new (_arena) Block_List();
49
50 // Init the sparse live arrays. This data is live on exit from here!
51 // The _live info is the live-out info.
52 _live = (IndexSet*)_arena->Amalloc(sizeof(IndexSet)*_cfg._num_blocks);
53 uint i;
54 for( i=0; i<_cfg._num_blocks; i++ ) {
55 _live[i].initialize(_maxlrg);
56 }
57
58 // Init the sparse arrays for delta-sets.
59 ResourceMark rm; // Nuke temp storage on exit
60
61 // Does the memory used by _defs and _deltas get reclaimed? Does it matter? TT
62
63 // Array of values defined locally in blocks
64 _defs = NEW_RESOURCE_ARRAY(IndexSet,_cfg._num_blocks);
65 for( i=0; i<_cfg._num_blocks; i++ ) {
66 _defs[i].initialize(_maxlrg);
67 }
68
69 // Array of delta-set pointers, indexed by block pre_order-1.
70 _deltas = NEW_RESOURCE_ARRAY(IndexSet*,_cfg._num_blocks);
71 memset( _deltas, 0, sizeof(IndexSet*)* _cfg._num_blocks);
72
73 _free_IndexSet = NULL;
74
75 // Blocks having done pass-1
76 VectorSet first_pass(Thread::current()->resource_area());
77
78 // Outer loop: must compute local live-in sets and push into predecessors.
79 uint iters = _cfg._num_blocks; // stat counters
80 for( uint j=_cfg._num_blocks; j>0; j-- ) {
81 Block *b = _cfg._blocks[j-1];
82
83 // Compute the local live-in set. Start with any new live-out bits.
84 IndexSet *use = getset( b );
85 IndexSet *def = &_defs[b->_pre_order-1];
86 DEBUG_ONLY(IndexSet *def_outside = getfreeset();)
87 uint i;
88 for( i=b->_nodes.size(); i>1; i-- ) {
89 Node *n = b->_nodes[i-1];
90 if( n->is_Phi() ) break;
91
92 uint r = _names[n->_idx];
93 assert(!def_outside->member(r), "Use of external LRG overlaps the same LRG defined in this block");
94 def->insert( r );
95 use->remove( r );
96 uint cnt = n->req();
97 for( uint k=1; k<cnt; k++ ) {
98 Node *nk = n->in(k);
99 uint nkidx = nk->_idx;
100 if( _cfg._bbs[nkidx] != b ) {
101 uint u = _names[nkidx];
102 use->insert( u );
103 DEBUG_ONLY(def_outside->insert( u );)
104 }
105 }
106 }
107 #ifdef ASSERT
108 def_outside->set_next(_free_IndexSet);
109 _free_IndexSet = def_outside; // Drop onto free list
110 #endif
111 // Remove anything defined by Phis and the block start instruction
112 for( uint k=i; k>0; k-- ) {
113 uint r = _names[b->_nodes[k-1]->_idx];
114 def->insert( r );
115 use->remove( r );
116 }
117
118 // Push these live-in things to predecessors
119 for( uint l=1; l<b->num_preds(); l++ ) {
120 Block *p = _cfg._bbs[b->pred(l)->_idx];
121 add_liveout( p, use, first_pass );
122
123 // PhiNode uses go in the live-out set of prior blocks.
124 for( uint k=i; k>0; k-- )
125 add_liveout( p, _names[b->_nodes[k-1]->in(l)->_idx], first_pass );
126 }
127 freeset( b );
128 first_pass.set(b->_pre_order);
129
130 // Inner loop: blocks that picked up new live-out values to be propagated
131 while( _worklist->size() ) {
132 // !!!!!
133 // #ifdef ASSERT
134 iters++;
135 // #endif
136 Block *b = _worklist->pop();
137 IndexSet *delta = getset(b);
138 assert( delta->count(), "missing delta set" );
139
140 // Add new-live-in to predecessors live-out sets
141 for( uint l=1; l<b->num_preds(); l++ )
142 add_liveout( _cfg._bbs[b->pred(l)->_idx], delta, first_pass );
143
144 freeset(b);
145 } // End of while-worklist-not-empty
146
147 } // End of for-all-blocks-outer-loop
148
149 // We explicitly clear all of the IndexSets which we are about to release.
150 // This allows us to recycle their internal memory into IndexSet's free list.
151
152 for( i=0; i<_cfg._num_blocks; i++ ) {
153 _defs[i].clear();
154 if (_deltas[i]) {
155 // Is this always true?
156 _deltas[i]->clear();
157 }
158 }
159 IndexSet *free = _free_IndexSet;
160 while (free != NULL) {
161 IndexSet *temp = free;
162 free = free->next();
163 temp->clear();
164 }
165
166 }
167
168 //------------------------------stats------------------------------------------
169 #ifndef PRODUCT
170 void PhaseLive::stats(uint iters) const {
171 }
172 #endif
173
174 //------------------------------getset-----------------------------------------
175 // Get an IndexSet for a block. Return existing one, if any. Make a new
176 // empty one if a prior one does not exist.
177 IndexSet *PhaseLive::getset( Block *p ) {
178 IndexSet *delta = _deltas[p->_pre_order-1];
179 if( !delta ) // Not on worklist?
180 // Get a free set; flag as being on worklist
181 delta = _deltas[p->_pre_order-1] = getfreeset();
182 return delta; // Return set of new live-out items
183 }
184
185 //------------------------------getfreeset-------------------------------------
186 // Pull from free list, or allocate. Internal allocation on the returned set
187 // is always from thread local storage.
188 IndexSet *PhaseLive::getfreeset( ) {
189 IndexSet *f = _free_IndexSet;
190 if( !f ) {
191 f = new IndexSet;
192 // f->set_arena(Thread::current()->resource_area());
193 f->initialize(_maxlrg, Thread::current()->resource_area());
194 } else {
195 // Pull from free list
196 _free_IndexSet = f->next();
197 //f->_cnt = 0; // Reset to empty
198 // f->set_arena(Thread::current()->resource_area());
199 f->initialize(_maxlrg, Thread::current()->resource_area());
200 }
201 return f;
202 }
203
204 //------------------------------freeset----------------------------------------
205 // Free an IndexSet from a block.
206 void PhaseLive::freeset( const Block *p ) {
207 IndexSet *f = _deltas[p->_pre_order-1];
208 f->set_next(_free_IndexSet);
209 _free_IndexSet = f; // Drop onto free list
210 _deltas[p->_pre_order-1] = NULL;
211 }
212
213 //------------------------------add_liveout------------------------------------
214 // Add a live-out value to a given blocks live-out set. If it is new, then
215 // also add it to the delta set and stick the block on the worklist.
216 void PhaseLive::add_liveout( Block *p, uint r, VectorSet &first_pass ) {
217 IndexSet *live = &_live[p->_pre_order-1];
218 if( live->insert(r) ) { // If actually inserted...
219 // We extended the live-out set. See if the value is generated locally.
220 // If it is not, then we must extend the live-in set.
221 if( !_defs[p->_pre_order-1].member( r ) ) {
222 if( !_deltas[p->_pre_order-1] && // Not on worklist?
223 first_pass.test(p->_pre_order) )
224 _worklist->push(p); // Actually go on worklist if already 1st pass
225 getset(p)->insert(r);
226 }
227 }
228 }
229
230
231 //------------------------------add_liveout------------------------------------
232 // Add a vector of live-out values to a given blocks live-out set.
233 void PhaseLive::add_liveout( Block *p, IndexSet *lo, VectorSet &first_pass ) {
234 IndexSet *live = &_live[p->_pre_order-1];
235 IndexSet *defs = &_defs[p->_pre_order-1];
236 IndexSet *on_worklist = _deltas[p->_pre_order-1];
237 IndexSet *delta = on_worklist ? on_worklist : getfreeset();
238
239 IndexSetIterator elements(lo);
240 uint r;
241 while ((r = elements.next()) != 0) {
242 if( live->insert(r) && // If actually inserted...
243 !defs->member( r ) ) // and not defined locally
244 delta->insert(r); // Then add to live-in set
245 }
246
247 if( delta->count() ) { // If actually added things
248 _deltas[p->_pre_order-1] = delta; // Flag as on worklist now
249 if( !on_worklist && // Not on worklist?
250 first_pass.test(p->_pre_order) )
251 _worklist->push(p); // Actually go on worklist if already 1st pass
252 } else { // Nothing there; just free it
253 delta->set_next(_free_IndexSet);
254 _free_IndexSet = delta; // Drop onto free list
255 }
256 }
257
258 #ifndef PRODUCT
259 //------------------------------dump-------------------------------------------
260 // Dump the live-out set for a block
261 void PhaseLive::dump( const Block *b ) const {
262 tty->print("Block %d: ",b->_pre_order);
263 tty->print("LiveOut: "); _live[b->_pre_order-1].dump();
264 uint cnt = b->_nodes.size();
265 for( uint i=0; i<cnt; i++ ) {
266 tty->print("L%d/", _names[b->_nodes[i]->_idx] );
267 b->_nodes[i]->dump();
268 }
269 tty->print("\n");
270 }
271
272 //------------------------------verify_base_ptrs-------------------------------
273 // Verify that base pointers and derived pointers are still sane.
274 void PhaseChaitin::verify_base_ptrs( ResourceArea *a ) const {
275 #ifdef ASSERT
276 Unique_Node_List worklist(a);
277 for( uint i = 0; i < _cfg._num_blocks; i++ ) {
278 Block *b = _cfg._blocks[i];
279 for( uint j = b->end_idx() + 1; j > 1; j-- ) {
280 Node *n = b->_nodes[j-1];
281 if( n->is_Phi() ) break;
282 // Found a safepoint?
283 if( n->is_MachSafePoint() ) {
284 MachSafePointNode *sfpt = n->as_MachSafePoint();
285 JVMState* jvms = sfpt->jvms();
286 if (jvms != NULL) {
287 // Now scan for a live derived pointer
288 if (jvms->oopoff() < sfpt->req()) {
289 // Check each derived/base pair
290 for (uint idx = jvms->oopoff(); idx < sfpt->req(); idx++) {
291 Node *check = sfpt->in(idx);
292 bool is_derived = ((idx - jvms->oopoff()) & 1) == 0;
293 // search upwards through spills and spill phis for AddP
294 worklist.clear();
295 worklist.push(check);
296 uint k = 0;
297 while( k < worklist.size() ) {
298 check = worklist.at(k);
299 assert(check,"Bad base or derived pointer");
300 // See PhaseChaitin::find_base_for_derived() for all cases.
301 int isc = check->is_Copy();
302 if( isc ) {
303 worklist.push(check->in(isc));
304 } else if( check->is_Phi() ) {
305 for (uint m = 1; m < check->req(); m++)
306 worklist.push(check->in(m));
307 } else if( check->is_Con() ) {
308 if (is_derived) {
309 // Derived is NULL+offset
310 assert(!is_derived || check->bottom_type()->is_ptr()->ptr() == TypePtr::Null,"Bad derived pointer");
311 } else {
312 assert(check->bottom_type()->is_ptr()->_offset == 0,"Bad base pointer");
313 // Base either ConP(NULL) or loadConP
314 if (check->is_Mach()) {
315 assert(check->as_Mach()->ideal_Opcode() == Op_ConP,"Bad base pointer");
316 } else {
317 assert(check->Opcode() == Op_ConP &&
318 check->bottom_type()->is_ptr()->ptr() == TypePtr::Null,"Bad base pointer");
319 }
320 }
321 } else if( check->bottom_type()->is_ptr()->_offset == 0 ) {
322 if(check->is_Proj() || check->is_Mach() &&
323 (check->as_Mach()->ideal_Opcode() == Op_CreateEx ||
324 check->as_Mach()->ideal_Opcode() == Op_ThreadLocal ||
325 check->as_Mach()->ideal_Opcode() == Op_CMoveP ||
326 check->as_Mach()->ideal_Opcode() == Op_CheckCastPP ||
327 #ifdef _LP64
328 UseCompressedOops && check->as_Mach()->ideal_Opcode() == Op_CastPP ||
329 UseCompressedOops && check->as_Mach()->ideal_Opcode() == Op_DecodeN ||
330 #endif
331 check->as_Mach()->ideal_Opcode() == Op_LoadP ||
332 check->as_Mach()->ideal_Opcode() == Op_LoadKlass)) {
333 // Valid nodes
334 } else {
335 check->dump();
336 assert(false,"Bad base or derived pointer");
337 }
338 } else {
339 assert(is_derived,"Bad base pointer");
340 assert(check->is_Mach() && check->as_Mach()->ideal_Opcode() == Op_AddP,"Bad derived pointer");
341 }
342 k++;
343 assert(k < 100000,"Derived pointer checking in infinite loop");
344 } // End while
345 }
346 } // End of check for derived pointers
347 } // End of Kcheck for debug info
348 } // End of if found a safepoint
349 } // End of forall instructions in block
350 } // End of forall blocks
351 #endif
352 }
353
354 //------------------------------verify-------------------------------------
355 // Verify that graphs and base pointers are still sane.
356 void PhaseChaitin::verify( ResourceArea *a, bool verify_ifg ) const {
357 #ifdef ASSERT
358 if( VerifyOpto || VerifyRegisterAllocator ) {
359 _cfg.verify();
360 verify_base_ptrs(a);
361 if(verify_ifg)
362 _ifg->verify(this);
363 }
364 #endif
365 }
366
367 #endif