1 /*
2 * Copyright (c) 1997, 2017, 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 "precompiled.hpp"
26 #include "memory/allocation.inline.hpp"
27 #include "memory/resourceArea.hpp"
28 #include "opto/callnode.hpp"
29 #include "opto/chaitin.hpp"
30 #include "opto/live.hpp"
31 #include "opto/machnode.hpp"
32
33
34 // Compute live-in/live-out. We use a totally incremental algorithm. The LIVE
35 // problem is monotonic. The steady-state solution looks like this: pull a
36 // block from the worklist. It has a set of delta's - values which are newly
37 // live-in from the block. Push these to the live-out sets of all predecessor
38 // blocks. At each predecessor, the new live-out values are ANDed with what is
39 // already live-out (extra stuff is added to the live-out sets). Then the
40 // remaining new live-out values are ANDed with what is locally defined.
41 // Leftover bits become the new live-in for the predecessor block, and the pred
42 // block is put on the worklist.
43 // The locally live-in stuff is computed once and added to predecessor
44 // live-out sets. This separate compilation is done in the outer loop below.
45 PhaseLive::PhaseLive(const PhaseCFG &cfg, const LRG_List &names, Arena *arena, bool keep_deltas)
46 : Phase(LIVE),
47 _live(0),
48 _livein(0),
49 _cfg(cfg),
50 _names(names),
51 _arena(arena),
52 _keep_deltas(keep_deltas) {
53 }
54
55 void PhaseLive::compute(uint maxlrg) {
56 _maxlrg = maxlrg;
57 _worklist = new (_arena) Block_List();
58
59 // Init the sparse live arrays. This data is live on exit from here!
60 // The _live info is the live-out info.
61 _live = (IndexSet*)_arena->Amalloc(sizeof(IndexSet) * _cfg.number_of_blocks());
62 uint i;
63 for (i = 0; i < _cfg.number_of_blocks(); i++) {
64 _live[i].initialize(_maxlrg);
65 }
66
67 if (_keep_deltas) {
68 _livein = (IndexSet*)_arena->Amalloc(sizeof(IndexSet) * _cfg.number_of_blocks());
69 for (i = 0; i < _cfg.number_of_blocks(); i++) {
70 _livein[i].initialize(_maxlrg);
71 }
72 }
73
74 // Init the sparse arrays for delta-sets.
75 ResourceMark rm; // Nuke temp storage on exit
76
77 // Does the memory used by _defs and _deltas get reclaimed? Does it matter? TT
78
79 // Array of values defined locally in blocks
80 _defs = NEW_RESOURCE_ARRAY(IndexSet,_cfg.number_of_blocks());
81 for (i = 0; i < _cfg.number_of_blocks(); i++) {
82 _defs[i].initialize(_maxlrg);
83 }
84
85 // Array of delta-set pointers, indexed by block pre_order-1.
86 _deltas = NEW_RESOURCE_ARRAY(IndexSet*,_cfg.number_of_blocks());
87 memset( _deltas, 0, sizeof(IndexSet*)* _cfg.number_of_blocks());
88
89 _free_IndexSet = NULL;
90
91 // Blocks having done pass-1
92 VectorSet first_pass(Thread::current()->resource_area());
93
94 // Outer loop: must compute local live-in sets and push into predecessors.
95 for (uint j = _cfg.number_of_blocks(); j > 0; j--) {
96 Block* block = _cfg.get_block(j - 1);
97
98 // Compute the local live-in set. Start with any new live-out bits.
99 IndexSet* use = getset(block);
100 IndexSet* def = &_defs[block->_pre_order-1];
101 DEBUG_ONLY(IndexSet *def_outside = getfreeset();)
102 uint i;
103 for (i = block->number_of_nodes(); i > 1; i--) {
104 Node* n = block->get_node(i-1);
105 if (n->is_Phi()) {
106 break;
107 }
108
109 uint r = _names.at(n->_idx);
110 assert(!def_outside->member(r), "Use of external LRG overlaps the same LRG defined in this block");
111 def->insert( r );
112 use->remove( r );
113 uint cnt = n->req();
114 for (uint k = 1; k < cnt; k++) {
115 Node *nk = n->in(k);
116 uint nkidx = nk->_idx;
117 if (_cfg.get_block_for_node(nk) != block) {
118 uint u = _names.at(nkidx);
119 use->insert(u);
120 DEBUG_ONLY(def_outside->insert(u);)
121 }
122 }
123 }
124 #ifdef ASSERT
125 def_outside->set_next(_free_IndexSet);
126 _free_IndexSet = def_outside; // Drop onto free list
127 #endif
128 // Remove anything defined by Phis and the block start instruction
129 for (uint k = i; k > 0; k--) {
130 uint r = _names.at(block->get_node(k - 1)->_idx);
131 def->insert(r);
132 use->remove(r);
133 }
134
135 // Push these live-in things to predecessors
136 for (uint l = 1; l < block->num_preds(); l++) {
137 Block* p = _cfg.get_block_for_node(block->pred(l));
138 add_liveout(p, use, first_pass);
139
140 // PhiNode uses go in the live-out set of prior blocks.
141 for (uint k = i; k > 0; k--) {
142 Node *phi = block->get_node(k - 1);
143 if (l < phi->req()) {
144 add_liveout(p, _names.at(phi->in(l)->_idx), first_pass);
145 }
146 }
147 }
148 freeset(block);
149 first_pass.set(block->_pre_order);
150
151 // Inner loop: blocks that picked up new live-out values to be propagated
152 while (_worklist->size()) {
153 Block* block = _worklist->pop();
154 IndexSet *delta = getset(block);
155 assert( delta->count(), "missing delta set" );
156
157 // Add new-live-in to predecessors live-out sets
158 for (uint l = 1; l < block->num_preds(); l++) {
159 Block* predecessor = _cfg.get_block_for_node(block->pred(l));
160 add_liveout(predecessor, delta, first_pass);
161 }
162
163 freeset(block);
164 } // End of while-worklist-not-empty
165
166 } // End of for-all-blocks-outer-loop
167
168 // We explicitly clear all of the IndexSets which we are about to release.
169 // This allows us to recycle their internal memory into IndexSet's free list.
170
171 for (i = 0; i < _cfg.number_of_blocks(); i++) {
172 _defs[i].clear();
173 if (_deltas[i]) {
174 // Is this always true?
175 _deltas[i]->clear();
176 }
177 }
178 IndexSet *free = _free_IndexSet;
179 while (free != NULL) {
180 IndexSet *temp = free;
181 free = free->next();
182 temp->clear();
183 }
184
185 }
186
187 #ifndef PRODUCT
188 void PhaseLive::stats(uint iters) const {
189 }
190 #endif
191
192 // Get an IndexSet for a block. Return existing one, if any. Make a new
193 // empty one if a prior one does not exist.
194 IndexSet *PhaseLive::getset( Block *p ) {
195 IndexSet *delta = _deltas[p->_pre_order-1];
196 if( !delta ) // Not on worklist?
197 // Get a free set; flag as being on worklist
198 delta = _deltas[p->_pre_order-1] = getfreeset();
199 return delta; // Return set of new live-out items
200 }
201
202 // Pull from free list, or allocate. Internal allocation on the returned set
203 // is always from thread local storage.
204 IndexSet *PhaseLive::getfreeset( ) {
205 IndexSet *f = _free_IndexSet;
206 if( !f ) {
207 f = new IndexSet;
208 // f->set_arena(Thread::current()->resource_area());
209 f->initialize(_maxlrg, Thread::current()->resource_area());
210 } else {
211 // Pull from free list
212 _free_IndexSet = f->next();
213 //f->_cnt = 0; // Reset to empty
214 // f->set_arena(Thread::current()->resource_area());
215 f->initialize(_maxlrg, Thread::current()->resource_area());
216 }
217 return f;
218 }
219
220 // Free an IndexSet from a block.
221 void PhaseLive::freeset( Block *p ) {
222 IndexSet *f = _deltas[p->_pre_order-1];
223 if ( _keep_deltas ) {
224 add_livein(p, f);
225 }
226 f->set_next(_free_IndexSet);
227 _free_IndexSet = f; // Drop onto free list
228 _deltas[p->_pre_order-1] = NULL;
229 }
230
231 // Add a live-out value to a given blocks live-out set. If it is new, then
232 // also add it to the delta set and stick the block on the worklist.
233 void PhaseLive::add_liveout( Block *p, uint r, VectorSet &first_pass ) {
234 IndexSet *live = &_live[p->_pre_order-1];
235 if( live->insert(r) ) { // If actually inserted...
236 // We extended the live-out set. See if the value is generated locally.
237 // If it is not, then we must extend the live-in set.
238 if( !_defs[p->_pre_order-1].member( r ) ) {
239 if( !_deltas[p->_pre_order-1] && // Not on worklist?
240 first_pass.test(p->_pre_order) )
241 _worklist->push(p); // Actually go on worklist if already 1st pass
242 getset(p)->insert(r);
243 }
244 }
245 }
246
247 // Add a vector of live-out values to a given blocks live-out set.
248 void PhaseLive::add_liveout( Block *p, IndexSet *lo, VectorSet &first_pass ) {
249 IndexSet *live = &_live[p->_pre_order-1];
250 IndexSet *defs = &_defs[p->_pre_order-1];
251 IndexSet *on_worklist = _deltas[p->_pre_order-1];
252 IndexSet *delta = on_worklist ? on_worklist : getfreeset();
253
254 IndexSetIterator elements(lo);
255 uint r;
256 while ((r = elements.next()) != 0) {
257 if( live->insert(r) && // If actually inserted...
258 !defs->member( r ) ) // and not defined locally
259 delta->insert(r); // Then add to live-in set
260 }
261
262 if( delta->count() ) { // If actually added things
263 _deltas[p->_pre_order-1] = delta; // Flag as on worklist now
264 if( !on_worklist && // Not on worklist?
265 first_pass.test(p->_pre_order) )
266 _worklist->push(p); // Actually go on worklist if already 1st pass
267 } else { // Nothing there; just free it
268 delta->set_next(_free_IndexSet);
269 _free_IndexSet = delta; // Drop onto free list
270 }
271 }
272
273 // Add a vector of live-in values to a given blocks live-in set.
274 void PhaseLive::add_livein(Block *p, IndexSet *lo) {
275 IndexSet *livein = &_livein[p->_pre_order-1];
276 IndexSetIterator elements(lo);
277 uint r;
278 while ((r = elements.next()) != 0) {
279 livein->insert(r); // Then add to live-in set
280 }
281 }
282
283 #ifndef PRODUCT
284 // Dump the live-out set for a block
285 void PhaseLive::dump( const Block *b ) const {
286 tty->print("Block %d: ",b->_pre_order);
287 if ( _keep_deltas ) {
288 tty->print("LiveIn: "); _livein[b->_pre_order-1].dump();
289 }
290 tty->print("LiveOut: "); _live[b->_pre_order-1].dump();
291 uint cnt = b->number_of_nodes();
292 for( uint i=0; i<cnt; i++ ) {
293 tty->print("L%d/", _names.at(b->get_node(i)->_idx));
294 b->get_node(i)->dump();
295 }
296 tty->print("\n");
297 }
298
299 // Verify that base pointers and derived pointers are still sane.
300 void PhaseChaitin::verify_base_ptrs( ResourceArea *a ) const {
301 #ifdef ASSERT
302 Unique_Node_List worklist(a);
303 for (uint i = 0; i < _cfg.number_of_blocks(); i++) {
304 Block* block = _cfg.get_block(i);
305 for (uint j = block->end_idx() + 1; j > 1; j--) {
306 Node* n = block->get_node(j-1);
307 if (n->is_Phi()) {
308 break;
309 }
310 // Found a safepoint?
311 if (n->is_MachSafePoint()) {
312 MachSafePointNode *sfpt = n->as_MachSafePoint();
313 JVMState* jvms = sfpt->jvms();
314 if (jvms != NULL) {
315 // Now scan for a live derived pointer
316 if (jvms->oopoff() < sfpt->req()) {
317 // Check each derived/base pair
318 for (uint idx = jvms->oopoff(); idx < sfpt->req(); idx++) {
319 Node *check = sfpt->in(idx);
320 bool is_derived = ((idx - jvms->oopoff()) & 1) == 0;
321 // search upwards through spills and spill phis for AddP
322 worklist.clear();
323 worklist.push(check);
324 uint k = 0;
325 while( k < worklist.size() ) {
326 check = worklist.at(k);
327 assert(check,"Bad base or derived pointer");
328 // See PhaseChaitin::find_base_for_derived() for all cases.
329 int isc = check->is_Copy();
330 if( isc ) {
331 worklist.push(check->in(isc));
332 } else if( check->is_Phi() ) {
333 for (uint m = 1; m < check->req(); m++)
334 worklist.push(check->in(m));
335 } else if( check->is_Con() ) {
336 if (is_derived) {
337 // Derived is NULL+offset
338 assert(!is_derived || check->bottom_type()->is_ptr()->ptr() == TypePtr::Null,"Bad derived pointer");
339 } else {
340 assert(check->bottom_type()->is_ptr()->offset() == 0,"Bad base pointer");
341 // Base either ConP(NULL) or loadConP
342 if (check->is_Mach()) {
343 assert(check->as_Mach()->ideal_Opcode() == Op_ConP,"Bad base pointer");
344 } else {
345 assert(check->Opcode() == Op_ConP &&
346 check->bottom_type()->is_ptr()->ptr() == TypePtr::Null,"Bad base pointer");
347 }
348 }
349 } else if (check->bottom_type()->is_ptr()->offset() == 0) {
350 if(check->is_Proj() || (check->is_Mach() &&
351 (check->as_Mach()->ideal_Opcode() == Op_CreateEx ||
352 check->as_Mach()->ideal_Opcode() == Op_ThreadLocal ||
353 check->as_Mach()->ideal_Opcode() == Op_CMoveP ||
354 check->as_Mach()->ideal_Opcode() == Op_CheckCastPP ||
355 #ifdef _LP64
356 (UseCompressedOops && check->as_Mach()->ideal_Opcode() == Op_CastPP) ||
357 (UseCompressedOops && check->as_Mach()->ideal_Opcode() == Op_DecodeN) ||
358 (UseCompressedClassPointers && check->as_Mach()->ideal_Opcode() == Op_DecodeNKlass) ||
359 #endif
360 check->as_Mach()->ideal_Opcode() == Op_LoadP ||
361 check->as_Mach()->ideal_Opcode() == Op_LoadKlass))) {
362 // Valid nodes
363 } else {
364 check->dump();
365 assert(false,"Bad base or derived pointer");
366 }
367 } else {
368 assert(is_derived,"Bad base pointer");
369 assert(check->is_Mach() && check->as_Mach()->ideal_Opcode() == Op_AddP,"Bad derived pointer");
370 }
371 k++;
372 assert(k < 100000,"Derived pointer checking in infinite loop");
373 } // End while
374 }
375 } // End of check for derived pointers
376 } // End of Kcheck for debug info
377 } // End of if found a safepoint
378 } // End of forall instructions in block
379 } // End of forall blocks
380 #endif
381 }
382
383 // Verify that graphs and base pointers are still sane.
384 void PhaseChaitin::verify( ResourceArea *a, bool verify_ifg ) const {
385 #ifdef ASSERT
386 if( VerifyOpto || VerifyRegisterAllocator ) {
387 _cfg.verify();
388 verify_base_ptrs(a);
389 if(verify_ifg)
390 _ifg->verify(this);
391 }
392 #endif
393 }
394
395 #endif