1 /* 2 * Copyright (c) 1997, 2013, 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 "opto/callnode.hpp" 28 #include "opto/chaitin.hpp" 29 #include "opto/live.hpp" 30 #include "opto/machnode.hpp" 31 32 33 // Compute live-in/live-out. We use a totally incremental algorithm. The LIVE 34 // problem is monotonic. The steady-state solution looks like this: pull a 35 // block from the worklist. It has a set of delta's - values which are newly 36 // live-in from the block. Push these to the live-out sets of all predecessor 37 // blocks. At each predecessor, the new live-out values are ANDed with what is 38 // already live-out (extra stuff is added to the live-out sets). Then the 39 // remaining new live-out values are ANDed with what is locally defined. 40 // Leftover bits become the new live-in for the predecessor block, and the pred 41 // block is put on the worklist. 42 // The locally live-in stuff is computed once and added to predecessor 43 // live-out sets. This separate compilation is done in the outer loop below. 44 PhaseLive::PhaseLive( const PhaseCFG &cfg, const LRG_List &names, Arena *arena ) : Phase(LIVE), _cfg(cfg), _names(names), _arena(arena), _live(0) { 45 } 46 47 void PhaseLive::compute(uint maxlrg) { 48 _maxlrg = maxlrg; 49 _worklist = new (_arena) Block_List(); 50 51 // Init the sparse live arrays. This data is live on exit from here! 52 // The _live info is the live-out info. 53 _live = (IndexSet*)_arena->Amalloc(sizeof(IndexSet) * _cfg.number_of_blocks()); 54 uint i; 55 for (i = 0; i < _cfg.number_of_blocks(); i++) { 56 _live[i].initialize(_maxlrg); 57 } 58 59 // Init the sparse arrays for delta-sets. 60 ResourceMark rm; // Nuke temp storage on exit 61 62 // Does the memory used by _defs and _deltas get reclaimed? Does it matter? TT 63 64 // Array of values defined locally in blocks 65 _defs = NEW_RESOURCE_ARRAY(IndexSet,_cfg.number_of_blocks()); 66 for (i = 0; i < _cfg.number_of_blocks(); i++) { 67 _defs[i].initialize(_maxlrg); 68 } 69 70 // Array of delta-set pointers, indexed by block pre_order-1. 71 _deltas = NEW_RESOURCE_ARRAY(IndexSet*,_cfg.number_of_blocks()); 72 memset( _deltas, 0, sizeof(IndexSet*)* _cfg.number_of_blocks()); 73 74 _free_IndexSet = NULL; 75 76 // Blocks having done pass-1 77 VectorSet first_pass(Thread::current()->resource_area()); 78 79 // Outer loop: must compute local live-in sets and push into predecessors. 80 for (uint j = _cfg.number_of_blocks(); j > 0; j--) { 81 Block* block = _cfg.get_block(j - 1); 82 83 // Compute the local live-in set. Start with any new live-out bits. 84 IndexSet* use = getset(block); 85 IndexSet* def = &_defs[block->_pre_order-1]; 86 DEBUG_ONLY(IndexSet *def_outside = getfreeset();) 87 uint i; 88 for (i = block->number_of_nodes(); i > 1; i--) { 89 Node* n = block->get_node(i-1); 90 if (n->is_Phi()) { 91 break; 92 } 93 94 uint r = _names.at(n->_idx); 95 assert(!def_outside->member(r), "Use of external LRG overlaps the same LRG defined in this block"); 96 def->insert( r ); 97 use->remove( r ); 98 uint cnt = n->req(); 99 for (uint k = 1; k < cnt; k++) { 100 Node *nk = n->in(k); 101 uint nkidx = nk->_idx; 102 if (_cfg.get_block_for_node(nk) != block) { 103 uint u = _names.at(nkidx); 104 use->insert(u); 105 DEBUG_ONLY(def_outside->insert(u);) 106 } 107 } 108 } 109 #ifdef ASSERT 110 def_outside->set_next(_free_IndexSet); 111 _free_IndexSet = def_outside; // Drop onto free list 112 #endif 113 // Remove anything defined by Phis and the block start instruction 114 for (uint k = i; k > 0; k--) { 115 uint r = _names.at(block->get_node(k - 1)->_idx); 116 def->insert(r); 117 use->remove(r); 118 } 119 120 // Push these live-in things to predecessors 121 for (uint l = 1; l < block->num_preds(); l++) { 122 Block* p = _cfg.get_block_for_node(block->pred(l)); 123 add_liveout(p, use, first_pass); 124 125 // PhiNode uses go in the live-out set of prior blocks. 126 for (uint k = i; k > 0; k--) { 127 add_liveout(p, _names.at(block->get_node(k-1)->in(l)->_idx), first_pass); 128 } 129 } 130 freeset(block); 131 first_pass.set(block->_pre_order); 132 133 // Inner loop: blocks that picked up new live-out values to be propagated 134 while (_worklist->size()) { 135 Block* block = _worklist->pop(); 136 IndexSet *delta = getset(block); 137 assert( delta->count(), "missing delta set" ); 138 139 // Add new-live-in to predecessors live-out sets 140 for (uint l = 1; l < block->num_preds(); l++) { 141 Block* predecessor = _cfg.get_block_for_node(block->pred(l)); 142 add_liveout(predecessor, delta, first_pass); 143 } 144 145 freeset(block); 146 } // End of while-worklist-not-empty 147 148 } // End of for-all-blocks-outer-loop 149 150 // We explicitly clear all of the IndexSets which we are about to release. 151 // This allows us to recycle their internal memory into IndexSet's free list. 152 153 for (i = 0; i < _cfg.number_of_blocks(); i++) { 154 _defs[i].clear(); 155 if (_deltas[i]) { 156 // Is this always true? 157 _deltas[i]->clear(); 158 } 159 } 160 IndexSet *free = _free_IndexSet; 161 while (free != NULL) { 162 IndexSet *temp = free; 163 free = free->next(); 164 temp->clear(); 165 } 166 167 } 168 169 #ifndef PRODUCT 170 void PhaseLive::stats(uint iters) const { 171 } 172 #endif 173 174 // Get an IndexSet for a block. Return existing one, if any. Make a new 175 // empty one if a prior one does not exist. 176 IndexSet *PhaseLive::getset( Block *p ) { 177 IndexSet *delta = _deltas[p->_pre_order-1]; 178 if( !delta ) // Not on worklist? 179 // Get a free set; flag as being on worklist 180 delta = _deltas[p->_pre_order-1] = getfreeset(); 181 return delta; // Return set of new live-out items 182 } 183 184 // Pull from free list, or allocate. Internal allocation on the returned set 185 // is always from thread local storage. 186 IndexSet *PhaseLive::getfreeset( ) { 187 IndexSet *f = _free_IndexSet; 188 if( !f ) { 189 f = new IndexSet; 190 // f->set_arena(Thread::current()->resource_area()); 191 f->initialize(_maxlrg, Thread::current()->resource_area()); 192 } else { 193 // Pull from free list 194 _free_IndexSet = f->next(); 195 //f->_cnt = 0; // Reset to empty 196 // f->set_arena(Thread::current()->resource_area()); 197 f->initialize(_maxlrg, Thread::current()->resource_area()); 198 } 199 return f; 200 } 201 202 // Free an IndexSet from a block. 203 void PhaseLive::freeset( const Block *p ) { 204 IndexSet *f = _deltas[p->_pre_order-1]; 205 f->set_next(_free_IndexSet); 206 _free_IndexSet = f; // Drop onto free list 207 _deltas[p->_pre_order-1] = NULL; 208 } 209 210 // Add a live-out value to a given blocks live-out set. If it is new, then 211 // also add it to the delta set and stick the block on the worklist. 212 void PhaseLive::add_liveout( Block *p, uint r, VectorSet &first_pass ) { 213 IndexSet *live = &_live[p->_pre_order-1]; 214 if( live->insert(r) ) { // If actually inserted... 215 // We extended the live-out set. See if the value is generated locally. 216 // If it is not, then we must extend the live-in set. 217 if( !_defs[p->_pre_order-1].member( r ) ) { 218 if( !_deltas[p->_pre_order-1] && // Not on worklist? 219 first_pass.test(p->_pre_order) ) 220 _worklist->push(p); // Actually go on worklist if already 1st pass 221 getset(p)->insert(r); 222 } 223 } 224 } 225 226 // Add a vector of live-out values to a given blocks live-out set. 227 void PhaseLive::add_liveout( Block *p, IndexSet *lo, VectorSet &first_pass ) { 228 IndexSet *live = &_live[p->_pre_order-1]; 229 IndexSet *defs = &_defs[p->_pre_order-1]; 230 IndexSet *on_worklist = _deltas[p->_pre_order-1]; 231 IndexSet *delta = on_worklist ? on_worklist : getfreeset(); 232 233 IndexSetIterator elements(lo); 234 uint r; 235 while ((r = elements.next()) != 0) { 236 if( live->insert(r) && // If actually inserted... 237 !defs->member( r ) ) // and not defined locally 238 delta->insert(r); // Then add to live-in set 239 } 240 241 if( delta->count() ) { // If actually added things 242 _deltas[p->_pre_order-1] = delta; // Flag as on worklist now 243 if( !on_worklist && // Not on worklist? 244 first_pass.test(p->_pre_order) ) 245 _worklist->push(p); // Actually go on worklist if already 1st pass 246 } else { // Nothing there; just free it 247 delta->set_next(_free_IndexSet); 248 _free_IndexSet = delta; // Drop onto free list 249 } 250 } 251 252 #ifndef PRODUCT 253 // Dump the live-out set for a block 254 void PhaseLive::dump( const Block *b ) const { 255 tty->print("Block %d: ",b->_pre_order); 256 tty->print("LiveOut: "); _live[b->_pre_order-1].dump(); 257 uint cnt = b->number_of_nodes(); 258 for( uint i=0; i<cnt; i++ ) { 259 tty->print("L%d/", _names.at(b->get_node(i)->_idx)); 260 b->get_node(i)->dump(); 261 } 262 tty->print("\n"); 263 } 264 265 // Verify that base pointers and derived pointers are still sane. 266 void PhaseChaitin::verify_base_ptrs( ResourceArea *a ) const { 267 #ifdef ASSERT 268 Unique_Node_List worklist(a); 269 for (uint i = 0; i < _cfg.number_of_blocks(); i++) { 270 Block* block = _cfg.get_block(i); 271 for (uint j = block->end_idx() + 1; j > 1; j--) { 272 Node* n = block->get_node(j-1); 273 if (n->is_Phi()) { 274 break; 275 } 276 // Found a safepoint? 277 if (n->is_MachSafePoint()) { 278 MachSafePointNode *sfpt = n->as_MachSafePoint(); 279 JVMState* jvms = sfpt->jvms(); 280 if (jvms != NULL) { 281 // Now scan for a live derived pointer 282 if (jvms->oopoff() < sfpt->req()) { 283 // Check each derived/base pair 284 for (uint idx = jvms->oopoff(); idx < sfpt->req(); idx++) { 285 Node *check = sfpt->in(idx); 286 bool is_derived = ((idx - jvms->oopoff()) & 1) == 0; 287 // search upwards through spills and spill phis for AddP 288 worklist.clear(); 289 worklist.push(check); 290 uint k = 0; 291 while( k < worklist.size() ) { 292 check = worklist.at(k); 293 assert(check,"Bad base or derived pointer"); 294 // See PhaseChaitin::find_base_for_derived() for all cases. 295 int isc = check->is_Copy(); 296 if( isc ) { 297 worklist.push(check->in(isc)); 298 } else if( check->is_Phi() ) { 299 for (uint m = 1; m < check->req(); m++) 300 worklist.push(check->in(m)); 301 } else if( check->is_Con() ) { 302 if (is_derived) { 303 // Derived is NULL+offset 304 assert(!is_derived || check->bottom_type()->is_ptr()->ptr() == TypePtr::Null,"Bad derived pointer"); 305 } else { 306 assert(check->bottom_type()->is_ptr()->_offset == 0,"Bad base pointer"); 307 // Base either ConP(NULL) or loadConP 308 if (check->is_Mach()) { 309 assert(check->as_Mach()->ideal_Opcode() == Op_ConP,"Bad base pointer"); 310 } else { 311 assert(check->Opcode() == Op_ConP && 312 check->bottom_type()->is_ptr()->ptr() == TypePtr::Null,"Bad base pointer"); 313 } 314 } 315 } else if( check->bottom_type()->is_ptr()->_offset == 0 ) { 316 if(check->is_Proj() || check->is_Mach() && 317 (check->as_Mach()->ideal_Opcode() == Op_CreateEx || 318 check->as_Mach()->ideal_Opcode() == Op_ThreadLocal || 319 check->as_Mach()->ideal_Opcode() == Op_CMoveP || 320 check->as_Mach()->ideal_Opcode() == Op_CheckCastPP || 321 #ifdef _LP64 322 UseCompressedOops && check->as_Mach()->ideal_Opcode() == Op_CastPP || 323 UseCompressedOops && check->as_Mach()->ideal_Opcode() == Op_DecodeN || 324 UseCompressedClassPointers && check->as_Mach()->ideal_Opcode() == Op_DecodeNKlass || 325 #endif 326 check->as_Mach()->ideal_Opcode() == Op_LoadP || 327 check->as_Mach()->ideal_Opcode() == Op_LoadKlass)) { 328 // Valid nodes 329 } else { 330 check->dump(); 331 assert(false,"Bad base or derived pointer"); 332 } 333 } else { 334 assert(is_derived,"Bad base pointer"); 335 assert(check->is_Mach() && check->as_Mach()->ideal_Opcode() == Op_AddP,"Bad derived pointer"); 336 } 337 k++; 338 assert(k < 100000,"Derived pointer checking in infinite loop"); 339 } // End while 340 } 341 } // End of check for derived pointers 342 } // End of Kcheck for debug info 343 } // End of if found a safepoint 344 } // End of forall instructions in block 345 } // End of forall blocks 346 #endif 347 } 348 349 // Verify that graphs and base pointers are still sane. 350 void PhaseChaitin::verify( ResourceArea *a, bool verify_ifg ) const { 351 #ifdef ASSERT 352 if( VerifyOpto || VerifyRegisterAllocator ) { 353 _cfg.verify(); 354 verify_base_ptrs(a); 355 if(verify_ifg) 356 _ifg->verify(this); 357 } 358 #endif 359 } 360 361 #endif