Mercurial > hg > graal-compiler
annotate src/share/vm/c1/c1_IR.cpp @ 948:89e0543e1737
6884624: Update copyright year
Summary: Update copyright for files that have been modified in 2009 through Septermber
Reviewed-by: tbell, ohair
| author | xdono |
|---|---|
| date | Tue, 22 Sep 2009 14:06:10 -0700 |
| parents | 9987d9d5eb0e |
| children | 3cf667df43ef |
| rev | line source |
|---|---|
| 0 | 1 /* |
| 948 | 2 * Copyright 1999-2009 Sun Microsystems, Inc. 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 * | |
| 19 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, | |
| 20 * CA 95054 USA or visit www.sun.com if you need additional information or | |
| 21 * have any questions. | |
| 22 * | |
| 23 */ | |
| 24 | |
| 25 # include "incls/_precompiled.incl" | |
| 26 # include "incls/_c1_IR.cpp.incl" | |
| 27 | |
| 28 | |
| 29 // Implementation of XHandlers | |
| 30 // | |
| 31 // Note: This code could eventually go away if we are | |
| 32 // just using the ciExceptionHandlerStream. | |
| 33 | |
| 34 XHandlers::XHandlers(ciMethod* method) : _list(method->exception_table_length()) { | |
| 35 ciExceptionHandlerStream s(method); | |
| 36 while (!s.is_done()) { | |
| 37 _list.append(new XHandler(s.handler())); | |
| 38 s.next(); | |
| 39 } | |
| 40 assert(s.count() == method->exception_table_length(), "exception table lengths inconsistent"); | |
| 41 } | |
| 42 | |
| 43 // deep copy of all XHandler contained in list | |
| 44 XHandlers::XHandlers(XHandlers* other) : | |
| 45 _list(other->length()) | |
| 46 { | |
| 47 for (int i = 0; i < other->length(); i++) { | |
| 48 _list.append(new XHandler(other->handler_at(i))); | |
| 49 } | |
| 50 } | |
| 51 | |
| 52 // Returns whether a particular exception type can be caught. Also | |
| 53 // returns true if klass is unloaded or any exception handler | |
| 54 // classes are unloaded. type_is_exact indicates whether the throw | |
| 55 // is known to be exactly that class or it might throw a subtype. | |
| 56 bool XHandlers::could_catch(ciInstanceKlass* klass, bool type_is_exact) const { | |
| 57 // the type is unknown so be conservative | |
| 58 if (!klass->is_loaded()) { | |
| 59 return true; | |
| 60 } | |
| 61 | |
| 62 for (int i = 0; i < length(); i++) { | |
| 63 XHandler* handler = handler_at(i); | |
| 64 if (handler->is_catch_all()) { | |
| 65 // catch of ANY | |
| 66 return true; | |
| 67 } | |
| 68 ciInstanceKlass* handler_klass = handler->catch_klass(); | |
| 69 // if it's unknown it might be catchable | |
| 70 if (!handler_klass->is_loaded()) { | |
| 71 return true; | |
| 72 } | |
| 73 // if the throw type is definitely a subtype of the catch type | |
| 74 // then it can be caught. | |
| 75 if (klass->is_subtype_of(handler_klass)) { | |
| 76 return true; | |
| 77 } | |
| 78 if (!type_is_exact) { | |
| 79 // If the type isn't exactly known then it can also be caught by | |
| 80 // catch statements where the inexact type is a subtype of the | |
| 81 // catch type. | |
| 82 // given: foo extends bar extends Exception | |
| 83 // throw bar can be caught by catch foo, catch bar, and catch | |
| 84 // Exception, however it can't be caught by any handlers without | |
| 85 // bar in its type hierarchy. | |
| 86 if (handler_klass->is_subtype_of(klass)) { | |
| 87 return true; | |
| 88 } | |
| 89 } | |
| 90 } | |
| 91 | |
| 92 return false; | |
| 93 } | |
| 94 | |
| 95 | |
| 96 bool XHandlers::equals(XHandlers* others) const { | |
| 97 if (others == NULL) return false; | |
| 98 if (length() != others->length()) return false; | |
| 99 | |
| 100 for (int i = 0; i < length(); i++) { | |
| 101 if (!handler_at(i)->equals(others->handler_at(i))) return false; | |
| 102 } | |
| 103 return true; | |
| 104 } | |
| 105 | |
| 106 bool XHandler::equals(XHandler* other) const { | |
| 107 assert(entry_pco() != -1 && other->entry_pco() != -1, "must have entry_pco"); | |
| 108 | |
| 109 if (entry_pco() != other->entry_pco()) return false; | |
| 110 if (scope_count() != other->scope_count()) return false; | |
| 111 if (_desc != other->_desc) return false; | |
| 112 | |
| 113 assert(entry_block() == other->entry_block(), "entry_block must be equal when entry_pco is equal"); | |
| 114 return true; | |
| 115 } | |
| 116 | |
| 117 | |
| 118 // Implementation of IRScope | |
| 119 | |
| 120 BlockBegin* IRScope::header_block(BlockBegin* entry, BlockBegin::Flag f, ValueStack* state) { | |
| 121 if (entry == NULL) return NULL; | |
| 122 assert(entry->is_set(f), "entry/flag mismatch"); | |
| 123 // create header block | |
| 124 BlockBegin* h = new BlockBegin(entry->bci()); | |
| 125 BlockEnd* g = new Goto(entry, false); | |
| 126 h->set_next(g, entry->bci()); | |
| 127 h->set_end(g); | |
| 128 h->set(f); | |
| 129 // setup header block end state | |
| 130 ValueStack* s = state->copy(); // can use copy since stack is empty (=> no phis) | |
| 131 assert(s->stack_is_empty(), "must have empty stack at entry point"); | |
| 132 g->set_state(s); | |
| 133 return h; | |
| 134 } | |
| 135 | |
| 136 | |
| 137 BlockBegin* IRScope::build_graph(Compilation* compilation, int osr_bci) { | |
| 138 GraphBuilder gm(compilation, this); | |
| 139 NOT_PRODUCT(if (PrintValueNumbering && Verbose) gm.print_stats()); | |
| 140 if (compilation->bailed_out()) return NULL; | |
| 141 return gm.start(); | |
| 142 } | |
| 143 | |
| 144 | |
| 145 IRScope::IRScope(Compilation* compilation, IRScope* caller, int caller_bci, ciMethod* method, int osr_bci, bool create_graph) | |
| 146 : _callees(2) | |
| 147 , _compilation(compilation) | |
| 148 , _lock_stack_size(-1) | |
| 149 , _requires_phi_function(method->max_locals()) | |
| 150 { | |
| 151 _caller = caller; | |
| 152 _caller_bci = caller == NULL ? -1 : caller_bci; | |
| 153 _caller_state = NULL; // Must be set later if needed | |
| 154 _level = caller == NULL ? 0 : caller->level() + 1; | |
| 155 _method = method; | |
| 156 _xhandlers = new XHandlers(method); | |
| 157 _number_of_locks = 0; | |
| 158 _monitor_pairing_ok = method->has_balanced_monitors(); | |
| 159 _start = NULL; | |
| 160 | |
| 161 if (osr_bci == -1) { | |
| 162 _requires_phi_function.clear(); | |
| 163 } else { | |
| 164 // selective creation of phi functions is not possibel in osr-methods | |
| 165 _requires_phi_function.set_range(0, method->max_locals()); | |
| 166 } | |
| 167 | |
| 168 assert(method->holder()->is_loaded() , "method holder must be loaded"); | |
| 169 | |
| 170 // build graph if monitor pairing is ok | |
| 171 if (create_graph && monitor_pairing_ok()) _start = build_graph(compilation, osr_bci); | |
| 172 } | |
| 173 | |
| 174 | |
| 175 int IRScope::max_stack() const { | |
| 176 int my_max = method()->max_stack(); | |
| 177 int callee_max = 0; | |
| 178 for (int i = 0; i < number_of_callees(); i++) { | |
| 179 callee_max = MAX2(callee_max, callee_no(i)->max_stack()); | |
| 180 } | |
| 181 return my_max + callee_max; | |
| 182 } | |
| 183 | |
| 184 | |
| 185 void IRScope::compute_lock_stack_size() { | |
| 186 if (!InlineMethodsWithExceptionHandlers) { | |
| 187 _lock_stack_size = 0; | |
| 188 return; | |
| 189 } | |
| 190 | |
| 191 // Figure out whether we have to preserve expression stack elements | |
| 192 // for parent scopes, and if so, how many | |
| 193 IRScope* cur_scope = this; | |
| 194 while (cur_scope != NULL && !cur_scope->xhandlers()->has_handlers()) { | |
| 195 cur_scope = cur_scope->caller(); | |
| 196 } | |
| 197 _lock_stack_size = (cur_scope == NULL ? 0 : | |
| 198 (cur_scope->caller_state() == NULL ? 0 : | |
| 199 cur_scope->caller_state()->stack_size())); | |
| 200 } | |
| 201 | |
| 202 int IRScope::top_scope_bci() const { | |
| 203 assert(!is_top_scope(), "no correct answer for top scope possible"); | |
| 204 const IRScope* scope = this; | |
| 205 while (!scope->caller()->is_top_scope()) { | |
| 206 scope = scope->caller(); | |
| 207 } | |
| 208 return scope->caller_bci(); | |
| 209 } | |
| 210 | |
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211 bool IRScopeDebugInfo::should_reexecute() { |
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212 ciMethod* cur_method = scope()->method(); |
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213 int cur_bci = bci(); |
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214 if (cur_method != NULL && cur_bci != SynchronizationEntryBCI) { |
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215 Bytecodes::Code code = cur_method->java_code_at_bci(cur_bci); |
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216 return Interpreter::bytecode_should_reexecute(code); |
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217 } else |
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218 return false; |
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219 } |
| 0 | 220 |
| 221 | |
| 222 // Implementation of CodeEmitInfo | |
| 223 | |
| 224 // Stack must be NON-null | |
| 225 CodeEmitInfo::CodeEmitInfo(int bci, ValueStack* stack, XHandlers* exception_handlers) | |
| 226 : _scope(stack->scope()) | |
| 227 , _bci(bci) | |
| 228 , _scope_debug_info(NULL) | |
| 229 , _oop_map(NULL) | |
| 230 , _stack(stack) | |
| 231 , _exception_handlers(exception_handlers) | |
| 232 , _next(NULL) | |
| 233 , _id(-1) { | |
| 234 assert(_stack != NULL, "must be non null"); | |
| 235 assert(_bci == SynchronizationEntryBCI || Bytecodes::is_defined(scope()->method()->java_code_at_bci(_bci)), "make sure bci points at a real bytecode"); | |
| 236 } | |
| 237 | |
| 238 | |
| 239 CodeEmitInfo::CodeEmitInfo(CodeEmitInfo* info, bool lock_stack_only) | |
| 240 : _scope(info->_scope) | |
| 241 , _exception_handlers(NULL) | |
| 242 , _bci(info->_bci) | |
| 243 , _scope_debug_info(NULL) | |
| 244 , _oop_map(NULL) { | |
| 245 if (lock_stack_only) { | |
| 246 if (info->_stack != NULL) { | |
| 247 _stack = info->_stack->copy_locks(); | |
| 248 } else { | |
| 249 _stack = NULL; | |
| 250 } | |
| 251 } else { | |
| 252 _stack = info->_stack; | |
| 253 } | |
| 254 | |
| 255 // deep copy of exception handlers | |
| 256 if (info->_exception_handlers != NULL) { | |
| 257 _exception_handlers = new XHandlers(info->_exception_handlers); | |
| 258 } | |
| 259 } | |
| 260 | |
| 261 | |
| 262 void CodeEmitInfo::record_debug_info(DebugInformationRecorder* recorder, int pc_offset) { | |
| 263 // record the safepoint before recording the debug info for enclosing scopes | |
| 264 recorder->add_safepoint(pc_offset, _oop_map->deep_copy()); | |
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265 _scope_debug_info->record_debug_info(recorder, pc_offset, true/*topmost*/); |
| 0 | 266 recorder->end_safepoint(pc_offset); |
| 267 } | |
| 268 | |
| 269 | |
| 270 void CodeEmitInfo::add_register_oop(LIR_Opr opr) { | |
| 271 assert(_oop_map != NULL, "oop map must already exist"); | |
| 272 assert(opr->is_single_cpu(), "should not call otherwise"); | |
| 273 | |
| 274 int frame_size = frame_map()->framesize(); | |
| 275 int arg_count = frame_map()->oop_map_arg_count(); | |
| 276 VMReg name = frame_map()->regname(opr); | |
| 277 _oop_map->set_oop(name); | |
| 278 } | |
| 279 | |
| 280 | |
| 281 | |
| 282 | |
| 283 // Implementation of IR | |
| 284 | |
| 285 IR::IR(Compilation* compilation, ciMethod* method, int osr_bci) : | |
| 286 _locals_size(in_WordSize(-1)) | |
| 287 , _num_loops(0) { | |
| 288 // initialize data structures | |
| 289 ValueType::initialize(); | |
| 290 Instruction::initialize(); | |
| 291 BlockBegin::initialize(); | |
| 292 GraphBuilder::initialize(); | |
| 293 // setup IR fields | |
| 294 _compilation = compilation; | |
| 295 _top_scope = new IRScope(compilation, NULL, -1, method, osr_bci, true); | |
| 296 _code = NULL; | |
| 297 } | |
| 298 | |
| 299 | |
| 300 void IR::optimize() { | |
| 301 Optimizer opt(this); | |
| 302 if (DoCEE) { | |
| 303 opt.eliminate_conditional_expressions(); | |
| 304 #ifndef PRODUCT | |
| 305 if (PrintCFG || PrintCFG1) { tty->print_cr("CFG after CEE"); print(true); } | |
| 306 if (PrintIR || PrintIR1 ) { tty->print_cr("IR after CEE"); print(false); } | |
| 307 #endif | |
| 308 } | |
| 309 if (EliminateBlocks) { | |
| 310 opt.eliminate_blocks(); | |
| 311 #ifndef PRODUCT | |
| 312 if (PrintCFG || PrintCFG1) { tty->print_cr("CFG after block elimination"); print(true); } | |
| 313 if (PrintIR || PrintIR1 ) { tty->print_cr("IR after block elimination"); print(false); } | |
| 314 #endif | |
| 315 } | |
| 316 if (EliminateNullChecks) { | |
| 317 opt.eliminate_null_checks(); | |
| 318 #ifndef PRODUCT | |
| 319 if (PrintCFG || PrintCFG1) { tty->print_cr("CFG after null check elimination"); print(true); } | |
| 320 if (PrintIR || PrintIR1 ) { tty->print_cr("IR after null check elimination"); print(false); } | |
| 321 #endif | |
| 322 } | |
| 323 } | |
| 324 | |
| 325 | |
| 326 static int sort_pairs(BlockPair** a, BlockPair** b) { | |
| 327 if ((*a)->from() == (*b)->from()) { | |
| 328 return (*a)->to()->block_id() - (*b)->to()->block_id(); | |
| 329 } else { | |
| 330 return (*a)->from()->block_id() - (*b)->from()->block_id(); | |
| 331 } | |
| 332 } | |
| 333 | |
| 334 | |
| 335 class CriticalEdgeFinder: public BlockClosure { | |
| 336 BlockPairList blocks; | |
| 337 IR* _ir; | |
| 338 | |
| 339 public: | |
| 340 CriticalEdgeFinder(IR* ir): _ir(ir) {} | |
| 341 void block_do(BlockBegin* bb) { | |
| 342 BlockEnd* be = bb->end(); | |
| 343 int nos = be->number_of_sux(); | |
| 344 if (nos >= 2) { | |
| 345 for (int i = 0; i < nos; i++) { | |
| 346 BlockBegin* sux = be->sux_at(i); | |
| 347 if (sux->number_of_preds() >= 2) { | |
| 348 blocks.append(new BlockPair(bb, sux)); | |
| 349 } | |
| 350 } | |
| 351 } | |
| 352 } | |
| 353 | |
| 354 void split_edges() { | |
| 355 BlockPair* last_pair = NULL; | |
| 356 blocks.sort(sort_pairs); | |
| 357 for (int i = 0; i < blocks.length(); i++) { | |
| 358 BlockPair* pair = blocks.at(i); | |
| 359 if (last_pair != NULL && pair->is_same(last_pair)) continue; | |
| 360 BlockBegin* from = pair->from(); | |
| 361 BlockBegin* to = pair->to(); | |
| 362 BlockBegin* split = from->insert_block_between(to); | |
| 363 #ifndef PRODUCT | |
| 364 if ((PrintIR || PrintIR1) && Verbose) { | |
| 365 tty->print_cr("Split critical edge B%d -> B%d (new block B%d)", | |
| 366 from->block_id(), to->block_id(), split->block_id()); | |
| 367 } | |
| 368 #endif | |
| 369 last_pair = pair; | |
| 370 } | |
| 371 } | |
| 372 }; | |
| 373 | |
| 374 void IR::split_critical_edges() { | |
| 375 CriticalEdgeFinder cef(this); | |
| 376 | |
| 377 iterate_preorder(&cef); | |
| 378 cef.split_edges(); | |
| 379 } | |
| 380 | |
| 381 | |
| 382 class UseCountComputer: public AllStatic { | |
| 383 private: | |
| 384 static void update_use_count(Value* n) { | |
| 385 // Local instructions and Phis for expression stack values at the | |
| 386 // start of basic blocks are not added to the instruction list | |
| 387 if ((*n)->bci() == -99 && (*n)->as_Local() == NULL && | |
| 388 (*n)->as_Phi() == NULL) { | |
| 389 assert(false, "a node was not appended to the graph"); | |
| 390 Compilation::current_compilation()->bailout("a node was not appended to the graph"); | |
| 391 } | |
| 392 // use n's input if not visited before | |
| 393 if (!(*n)->is_pinned() && !(*n)->has_uses()) { | |
| 394 // note: a) if the instruction is pinned, it will be handled by compute_use_count | |
| 395 // b) if the instruction has uses, it was touched before | |
| 396 // => in both cases we don't need to update n's values | |
| 397 uses_do(n); | |
| 398 } | |
| 399 // use n | |
| 400 (*n)->_use_count++; | |
| 401 } | |
| 402 | |
| 403 static Values* worklist; | |
| 404 static int depth; | |
| 405 enum { | |
| 406 max_recurse_depth = 20 | |
| 407 }; | |
| 408 | |
| 409 static void uses_do(Value* n) { | |
| 410 depth++; | |
| 411 if (depth > max_recurse_depth) { | |
| 412 // don't allow the traversal to recurse too deeply | |
| 413 worklist->push(*n); | |
| 414 } else { | |
| 415 (*n)->input_values_do(update_use_count); | |
| 416 // special handling for some instructions | |
| 417 if ((*n)->as_BlockEnd() != NULL) { | |
| 418 // note on BlockEnd: | |
| 419 // must 'use' the stack only if the method doesn't | |
| 420 // terminate, however, in those cases stack is empty | |
| 421 (*n)->state_values_do(update_use_count); | |
| 422 } | |
| 423 } | |
| 424 depth--; | |
| 425 } | |
| 426 | |
| 427 static void basic_compute_use_count(BlockBegin* b) { | |
| 428 depth = 0; | |
| 429 // process all pinned nodes as the roots of expression trees | |
| 430 for (Instruction* n = b; n != NULL; n = n->next()) { | |
| 431 if (n->is_pinned()) uses_do(&n); | |
| 432 } | |
| 433 assert(depth == 0, "should have counted back down"); | |
| 434 | |
| 435 // now process any unpinned nodes which recursed too deeply | |
| 436 while (worklist->length() > 0) { | |
| 437 Value t = worklist->pop(); | |
| 438 if (!t->is_pinned()) { | |
| 439 // compute the use count | |
| 440 uses_do(&t); | |
| 441 | |
| 442 // pin the instruction so that LIRGenerator doesn't recurse | |
| 443 // too deeply during it's evaluation. | |
| 444 t->pin(); | |
| 445 } | |
| 446 } | |
| 447 assert(depth == 0, "should have counted back down"); | |
| 448 } | |
| 449 | |
| 450 public: | |
| 451 static void compute(BlockList* blocks) { | |
| 452 worklist = new Values(); | |
| 453 blocks->blocks_do(basic_compute_use_count); | |
| 454 worklist = NULL; | |
| 455 } | |
| 456 }; | |
| 457 | |
| 458 | |
| 459 Values* UseCountComputer::worklist = NULL; | |
| 460 int UseCountComputer::depth = 0; | |
| 461 | |
| 462 // helper macro for short definition of trace-output inside code | |
| 463 #ifndef PRODUCT | |
| 464 #define TRACE_LINEAR_SCAN(level, code) \ | |
| 465 if (TraceLinearScanLevel >= level) { \ | |
| 466 code; \ | |
| 467 } | |
| 468 #else | |
| 469 #define TRACE_LINEAR_SCAN(level, code) | |
| 470 #endif | |
| 471 | |
| 472 class ComputeLinearScanOrder : public StackObj { | |
| 473 private: | |
| 474 int _max_block_id; // the highest block_id of a block | |
| 475 int _num_blocks; // total number of blocks (smaller than _max_block_id) | |
| 476 int _num_loops; // total number of loops | |
| 477 bool _iterative_dominators;// method requires iterative computation of dominatiors | |
| 478 | |
| 479 BlockList* _linear_scan_order; // the resulting list of blocks in correct order | |
| 480 | |
| 481 BitMap _visited_blocks; // used for recursive processing of blocks | |
| 482 BitMap _active_blocks; // used for recursive processing of blocks | |
| 483 BitMap _dominator_blocks; // temproary BitMap used for computation of dominator | |
| 484 intArray _forward_branches; // number of incoming forward branches for each block | |
| 485 BlockList _loop_end_blocks; // list of all loop end blocks collected during count_edges | |
| 486 BitMap2D _loop_map; // two-dimensional bit set: a bit is set if a block is contained in a loop | |
| 487 BlockList _work_list; // temporary list (used in mark_loops and compute_order) | |
| 488 | |
| 489 // accessors for _visited_blocks and _active_blocks | |
| 490 void init_visited() { _active_blocks.clear(); _visited_blocks.clear(); } | |
| 491 bool is_visited(BlockBegin* b) const { return _visited_blocks.at(b->block_id()); } | |
| 492 bool is_active(BlockBegin* b) const { return _active_blocks.at(b->block_id()); } | |
| 493 void set_visited(BlockBegin* b) { assert(!is_visited(b), "already set"); _visited_blocks.set_bit(b->block_id()); } | |
| 494 void set_active(BlockBegin* b) { assert(!is_active(b), "already set"); _active_blocks.set_bit(b->block_id()); } | |
| 495 void clear_active(BlockBegin* b) { assert(is_active(b), "not already"); _active_blocks.clear_bit(b->block_id()); } | |
| 496 | |
| 497 // accessors for _forward_branches | |
| 498 void inc_forward_branches(BlockBegin* b) { _forward_branches.at_put(b->block_id(), _forward_branches.at(b->block_id()) + 1); } | |
| 499 int dec_forward_branches(BlockBegin* b) { _forward_branches.at_put(b->block_id(), _forward_branches.at(b->block_id()) - 1); return _forward_branches.at(b->block_id()); } | |
| 500 | |
| 501 // accessors for _loop_map | |
| 502 bool is_block_in_loop (int loop_idx, BlockBegin* b) const { return _loop_map.at(loop_idx, b->block_id()); } | |
| 503 void set_block_in_loop (int loop_idx, BlockBegin* b) { _loop_map.set_bit(loop_idx, b->block_id()); } | |
| 504 void clear_block_in_loop(int loop_idx, int block_id) { _loop_map.clear_bit(loop_idx, block_id); } | |
| 505 | |
| 506 // count edges between blocks | |
| 507 void count_edges(BlockBegin* cur, BlockBegin* parent); | |
| 508 | |
| 509 // loop detection | |
| 510 void mark_loops(); | |
| 511 void clear_non_natural_loops(BlockBegin* start_block); | |
| 512 void assign_loop_depth(BlockBegin* start_block); | |
| 513 | |
| 514 // computation of final block order | |
| 515 BlockBegin* common_dominator(BlockBegin* a, BlockBegin* b); | |
| 516 void compute_dominator(BlockBegin* cur, BlockBegin* parent); | |
| 517 int compute_weight(BlockBegin* cur); | |
| 518 bool ready_for_processing(BlockBegin* cur); | |
| 519 void sort_into_work_list(BlockBegin* b); | |
| 520 void append_block(BlockBegin* cur); | |
| 521 void compute_order(BlockBegin* start_block); | |
| 522 | |
| 523 // fixup of dominators for non-natural loops | |
| 524 bool compute_dominators_iter(); | |
| 525 void compute_dominators(); | |
| 526 | |
| 527 // debug functions | |
| 528 NOT_PRODUCT(void print_blocks();) | |
| 529 DEBUG_ONLY(void verify();) | |
| 530 | |
| 531 public: | |
| 532 ComputeLinearScanOrder(BlockBegin* start_block); | |
| 533 | |
| 534 // accessors for final result | |
| 535 BlockList* linear_scan_order() const { return _linear_scan_order; } | |
| 536 int num_loops() const { return _num_loops; } | |
| 537 }; | |
| 538 | |
| 539 | |
| 540 ComputeLinearScanOrder::ComputeLinearScanOrder(BlockBegin* start_block) : | |
| 541 _max_block_id(BlockBegin::number_of_blocks()), | |
| 542 _num_blocks(0), | |
| 543 _num_loops(0), | |
| 544 _iterative_dominators(false), | |
| 545 _visited_blocks(_max_block_id), | |
| 546 _active_blocks(_max_block_id), | |
| 547 _dominator_blocks(_max_block_id), | |
| 548 _forward_branches(_max_block_id, 0), | |
| 549 _loop_end_blocks(8), | |
| 550 _work_list(8), | |
| 551 _linear_scan_order(NULL), // initialized later with correct size | |
| 552 _loop_map(0, 0) // initialized later with correct size | |
| 553 { | |
| 554 TRACE_LINEAR_SCAN(2, "***** computing linear-scan block order"); | |
| 555 | |
| 556 init_visited(); | |
| 557 count_edges(start_block, NULL); | |
| 558 | |
| 559 if (_num_loops > 0) { | |
| 560 mark_loops(); | |
| 561 clear_non_natural_loops(start_block); | |
| 562 assign_loop_depth(start_block); | |
| 563 } | |
| 564 | |
| 565 compute_order(start_block); | |
| 566 compute_dominators(); | |
| 567 | |
| 568 NOT_PRODUCT(print_blocks()); | |
| 569 DEBUG_ONLY(verify()); | |
| 570 } | |
| 571 | |
| 572 | |
| 573 // Traverse the CFG: | |
| 574 // * count total number of blocks | |
| 575 // * count all incoming edges and backward incoming edges | |
| 576 // * number loop header blocks | |
| 577 // * create a list with all loop end blocks | |
| 578 void ComputeLinearScanOrder::count_edges(BlockBegin* cur, BlockBegin* parent) { | |
| 579 TRACE_LINEAR_SCAN(3, tty->print_cr("Enter count_edges for block B%d coming from B%d", cur->block_id(), parent != NULL ? parent->block_id() : -1)); | |
| 580 assert(cur->dominator() == NULL, "dominator already initialized"); | |
| 581 | |
| 582 if (is_active(cur)) { | |
| 583 TRACE_LINEAR_SCAN(3, tty->print_cr("backward branch")); | |
| 584 assert(is_visited(cur), "block must be visisted when block is active"); | |
| 585 assert(parent != NULL, "must have parent"); | |
| 586 | |
| 587 cur->set(BlockBegin::linear_scan_loop_header_flag); | |
| 588 cur->set(BlockBegin::backward_branch_target_flag); | |
| 589 | |
| 590 parent->set(BlockBegin::linear_scan_loop_end_flag); | |
|
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591 |
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592 // When a loop header is also the start of an exception handler, then the backward branch is |
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593 // an exception edge. Because such edges are usually critical edges which cannot be split, the |
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594 // loop must be excluded here from processing. |
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595 if (cur->is_set(BlockBegin::exception_entry_flag)) { |
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596 // Make sure that dominators are correct in this weird situation |
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597 _iterative_dominators = true; |
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598 return; |
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599 } |
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600 assert(parent->number_of_sux() == 1 && parent->sux_at(0) == cur, |
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601 "loop end blocks must have one successor (critical edges are split)"); |
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602 |
| 0 | 603 _loop_end_blocks.append(parent); |
| 604 return; | |
| 605 } | |
| 606 | |
| 607 // increment number of incoming forward branches | |
| 608 inc_forward_branches(cur); | |
| 609 | |
| 610 if (is_visited(cur)) { | |
| 611 TRACE_LINEAR_SCAN(3, tty->print_cr("block already visited")); | |
| 612 return; | |
| 613 } | |
| 614 | |
| 615 _num_blocks++; | |
| 616 set_visited(cur); | |
| 617 set_active(cur); | |
| 618 | |
| 619 // recursive call for all successors | |
| 620 int i; | |
| 621 for (i = cur->number_of_sux() - 1; i >= 0; i--) { | |
| 622 count_edges(cur->sux_at(i), cur); | |
| 623 } | |
| 624 for (i = cur->number_of_exception_handlers() - 1; i >= 0; i--) { | |
| 625 count_edges(cur->exception_handler_at(i), cur); | |
| 626 } | |
| 627 | |
| 628 clear_active(cur); | |
| 629 | |
| 630 // Each loop has a unique number. | |
| 631 // When multiple loops are nested, assign_loop_depth assumes that the | |
| 632 // innermost loop has the lowest number. This is guaranteed by setting | |
| 633 // the loop number after the recursive calls for the successors above | |
| 634 // have returned. | |
| 635 if (cur->is_set(BlockBegin::linear_scan_loop_header_flag)) { | |
| 636 assert(cur->loop_index() == -1, "cannot set loop-index twice"); | |
| 637 TRACE_LINEAR_SCAN(3, tty->print_cr("Block B%d is loop header of loop %d", cur->block_id(), _num_loops)); | |
| 638 | |
| 639 cur->set_loop_index(_num_loops); | |
| 640 _num_loops++; | |
| 641 } | |
| 642 | |
| 643 TRACE_LINEAR_SCAN(3, tty->print_cr("Finished count_edges for block B%d", cur->block_id())); | |
| 644 } | |
| 645 | |
| 646 | |
| 647 void ComputeLinearScanOrder::mark_loops() { | |
| 648 TRACE_LINEAR_SCAN(3, tty->print_cr("----- marking loops")); | |
| 649 | |
| 650 _loop_map = BitMap2D(_num_loops, _max_block_id); | |
| 651 _loop_map.clear(); | |
| 652 | |
| 653 for (int i = _loop_end_blocks.length() - 1; i >= 0; i--) { | |
| 654 BlockBegin* loop_end = _loop_end_blocks.at(i); | |
| 655 BlockBegin* loop_start = loop_end->sux_at(0); | |
| 656 int loop_idx = loop_start->loop_index(); | |
| 657 | |
| 658 TRACE_LINEAR_SCAN(3, tty->print_cr("Processing loop from B%d to B%d (loop %d):", loop_start->block_id(), loop_end->block_id(), loop_idx)); | |
| 659 assert(loop_end->is_set(BlockBegin::linear_scan_loop_end_flag), "loop end flag must be set"); | |
| 660 assert(loop_end->number_of_sux() == 1, "incorrect number of successors"); | |
| 661 assert(loop_start->is_set(BlockBegin::linear_scan_loop_header_flag), "loop header flag must be set"); | |
| 662 assert(loop_idx >= 0 && loop_idx < _num_loops, "loop index not set"); | |
| 663 assert(_work_list.is_empty(), "work list must be empty before processing"); | |
| 664 | |
| 665 // add the end-block of the loop to the working list | |
| 666 _work_list.push(loop_end); | |
| 667 set_block_in_loop(loop_idx, loop_end); | |
| 668 do { | |
| 669 BlockBegin* cur = _work_list.pop(); | |
| 670 | |
| 671 TRACE_LINEAR_SCAN(3, tty->print_cr(" processing B%d", cur->block_id())); | |
| 672 assert(is_block_in_loop(loop_idx, cur), "bit in loop map must be set when block is in work list"); | |
| 673 | |
| 674 // recursive processing of all predecessors ends when start block of loop is reached | |
| 675 if (cur != loop_start && !cur->is_set(BlockBegin::osr_entry_flag)) { | |
| 676 for (int j = cur->number_of_preds() - 1; j >= 0; j--) { | |
| 677 BlockBegin* pred = cur->pred_at(j); | |
| 678 | |
| 679 if (!is_block_in_loop(loop_idx, pred) /*&& !pred->is_set(BlockBeginosr_entry_flag)*/) { | |
| 680 // this predecessor has not been processed yet, so add it to work list | |
| 681 TRACE_LINEAR_SCAN(3, tty->print_cr(" pushing B%d", pred->block_id())); | |
| 682 _work_list.push(pred); | |
| 683 set_block_in_loop(loop_idx, pred); | |
| 684 } | |
| 685 } | |
| 686 } | |
| 687 } while (!_work_list.is_empty()); | |
| 688 } | |
| 689 } | |
| 690 | |
| 691 | |
| 692 // check for non-natural loops (loops where the loop header does not dominate | |
| 693 // all other loop blocks = loops with mulitple entries). | |
| 694 // such loops are ignored | |
| 695 void ComputeLinearScanOrder::clear_non_natural_loops(BlockBegin* start_block) { | |
| 696 for (int i = _num_loops - 1; i >= 0; i--) { | |
| 697 if (is_block_in_loop(i, start_block)) { | |
| 698 // loop i contains the entry block of the method | |
| 699 // -> this is not a natural loop, so ignore it | |
| 700 TRACE_LINEAR_SCAN(2, tty->print_cr("Loop %d is non-natural, so it is ignored", i)); | |
| 701 | |
| 702 for (int block_id = _max_block_id - 1; block_id >= 0; block_id--) { | |
| 703 clear_block_in_loop(i, block_id); | |
| 704 } | |
| 705 _iterative_dominators = true; | |
| 706 } | |
| 707 } | |
| 708 } | |
| 709 | |
| 710 void ComputeLinearScanOrder::assign_loop_depth(BlockBegin* start_block) { | |
| 711 TRACE_LINEAR_SCAN(3, "----- computing loop-depth and weight"); | |
| 712 init_visited(); | |
| 713 | |
| 714 assert(_work_list.is_empty(), "work list must be empty before processing"); | |
| 715 _work_list.append(start_block); | |
| 716 | |
| 717 do { | |
| 718 BlockBegin* cur = _work_list.pop(); | |
| 719 | |
| 720 if (!is_visited(cur)) { | |
| 721 set_visited(cur); | |
| 722 TRACE_LINEAR_SCAN(4, tty->print_cr("Computing loop depth for block B%d", cur->block_id())); | |
| 723 | |
| 724 // compute loop-depth and loop-index for the block | |
| 725 assert(cur->loop_depth() == 0, "cannot set loop-depth twice"); | |
| 726 int i; | |
| 727 int loop_depth = 0; | |
| 728 int min_loop_idx = -1; | |
| 729 for (i = _num_loops - 1; i >= 0; i--) { | |
| 730 if (is_block_in_loop(i, cur)) { | |
| 731 loop_depth++; | |
| 732 min_loop_idx = i; | |
| 733 } | |
| 734 } | |
| 735 cur->set_loop_depth(loop_depth); | |
| 736 cur->set_loop_index(min_loop_idx); | |
| 737 | |
| 738 // append all unvisited successors to work list | |
| 739 for (i = cur->number_of_sux() - 1; i >= 0; i--) { | |
| 740 _work_list.append(cur->sux_at(i)); | |
| 741 } | |
| 742 for (i = cur->number_of_exception_handlers() - 1; i >= 0; i--) { | |
| 743 _work_list.append(cur->exception_handler_at(i)); | |
| 744 } | |
| 745 } | |
| 746 } while (!_work_list.is_empty()); | |
| 747 } | |
| 748 | |
| 749 | |
| 750 BlockBegin* ComputeLinearScanOrder::common_dominator(BlockBegin* a, BlockBegin* b) { | |
| 751 assert(a != NULL && b != NULL, "must have input blocks"); | |
| 752 | |
| 753 _dominator_blocks.clear(); | |
| 754 while (a != NULL) { | |
| 755 _dominator_blocks.set_bit(a->block_id()); | |
| 756 assert(a->dominator() != NULL || a == _linear_scan_order->at(0), "dominator must be initialized"); | |
| 757 a = a->dominator(); | |
| 758 } | |
| 759 while (b != NULL && !_dominator_blocks.at(b->block_id())) { | |
| 760 assert(b->dominator() != NULL || b == _linear_scan_order->at(0), "dominator must be initialized"); | |
| 761 b = b->dominator(); | |
| 762 } | |
| 763 | |
| 764 assert(b != NULL, "could not find dominator"); | |
| 765 return b; | |
| 766 } | |
| 767 | |
| 768 void ComputeLinearScanOrder::compute_dominator(BlockBegin* cur, BlockBegin* parent) { | |
| 769 if (cur->dominator() == NULL) { | |
| 770 TRACE_LINEAR_SCAN(4, tty->print_cr("DOM: initializing dominator of B%d to B%d", cur->block_id(), parent->block_id())); | |
| 771 cur->set_dominator(parent); | |
| 772 | |
| 773 } else if (!(cur->is_set(BlockBegin::linear_scan_loop_header_flag) && parent->is_set(BlockBegin::linear_scan_loop_end_flag))) { | |
| 774 TRACE_LINEAR_SCAN(4, tty->print_cr("DOM: computing dominator of B%d: common dominator of B%d and B%d is B%d", cur->block_id(), parent->block_id(), cur->dominator()->block_id(), common_dominator(cur->dominator(), parent)->block_id())); | |
| 775 assert(cur->number_of_preds() > 1, ""); | |
| 776 cur->set_dominator(common_dominator(cur->dominator(), parent)); | |
| 777 } | |
| 778 } | |
| 779 | |
| 780 | |
| 781 int ComputeLinearScanOrder::compute_weight(BlockBegin* cur) { | |
| 782 BlockBegin* single_sux = NULL; | |
| 783 if (cur->number_of_sux() == 1) { | |
| 784 single_sux = cur->sux_at(0); | |
| 785 } | |
| 786 | |
| 787 // limit loop-depth to 15 bit (only for security reason, it will never be so big) | |
| 788 int weight = (cur->loop_depth() & 0x7FFF) << 16; | |
| 789 | |
| 790 // general macro for short definition of weight flags | |
| 791 // the first instance of INC_WEIGHT_IF has the highest priority | |
| 792 int cur_bit = 15; | |
| 793 #define INC_WEIGHT_IF(condition) if ((condition)) { weight |= (1 << cur_bit); } cur_bit--; | |
| 794 | |
| 795 // this is necessery for the (very rare) case that two successing blocks have | |
| 796 // the same loop depth, but a different loop index (can happen for endless loops | |
| 797 // with exception handlers) | |
| 798 INC_WEIGHT_IF(!cur->is_set(BlockBegin::linear_scan_loop_header_flag)); | |
| 799 | |
| 800 // loop end blocks (blocks that end with a backward branch) are added | |
| 801 // after all other blocks of the loop. | |
| 802 INC_WEIGHT_IF(!cur->is_set(BlockBegin::linear_scan_loop_end_flag)); | |
| 803 | |
| 804 // critical edge split blocks are prefered because than they have a bigger | |
| 805 // proability to be completely empty | |
| 806 INC_WEIGHT_IF(cur->is_set(BlockBegin::critical_edge_split_flag)); | |
| 807 | |
| 808 // exceptions should not be thrown in normal control flow, so these blocks | |
| 809 // are added as late as possible | |
| 810 INC_WEIGHT_IF(cur->end()->as_Throw() == NULL && (single_sux == NULL || single_sux->end()->as_Throw() == NULL)); | |
| 811 INC_WEIGHT_IF(cur->end()->as_Return() == NULL && (single_sux == NULL || single_sux->end()->as_Return() == NULL)); | |
| 812 | |
| 813 // exceptions handlers are added as late as possible | |
| 814 INC_WEIGHT_IF(!cur->is_set(BlockBegin::exception_entry_flag)); | |
| 815 | |
| 816 // guarantee that weight is > 0 | |
| 817 weight |= 1; | |
| 818 | |
| 819 #undef INC_WEIGHT_IF | |
| 820 assert(cur_bit >= 0, "too many flags"); | |
| 821 assert(weight > 0, "weight cannot become negative"); | |
| 822 | |
| 823 return weight; | |
| 824 } | |
| 825 | |
| 826 bool ComputeLinearScanOrder::ready_for_processing(BlockBegin* cur) { | |
| 827 // Discount the edge just traveled. | |
| 828 // When the number drops to zero, all forward branches were processed | |
| 829 if (dec_forward_branches(cur) != 0) { | |
| 830 return false; | |
| 831 } | |
| 832 | |
| 833 assert(_linear_scan_order->index_of(cur) == -1, "block already processed (block can be ready only once)"); | |
| 834 assert(_work_list.index_of(cur) == -1, "block already in work-list (block can be ready only once)"); | |
| 835 return true; | |
| 836 } | |
| 837 | |
| 838 void ComputeLinearScanOrder::sort_into_work_list(BlockBegin* cur) { | |
| 839 assert(_work_list.index_of(cur) == -1, "block already in work list"); | |
| 840 | |
| 841 int cur_weight = compute_weight(cur); | |
| 842 | |
| 843 // the linear_scan_number is used to cache the weight of a block | |
| 844 cur->set_linear_scan_number(cur_weight); | |
| 845 | |
| 846 #ifndef PRODUCT | |
| 847 if (StressLinearScan) { | |
| 848 _work_list.insert_before(0, cur); | |
| 849 return; | |
| 850 } | |
| 851 #endif | |
| 852 | |
| 853 _work_list.append(NULL); // provide space for new element | |
| 854 | |
| 855 int insert_idx = _work_list.length() - 1; | |
| 856 while (insert_idx > 0 && _work_list.at(insert_idx - 1)->linear_scan_number() > cur_weight) { | |
| 857 _work_list.at_put(insert_idx, _work_list.at(insert_idx - 1)); | |
| 858 insert_idx--; | |
| 859 } | |
| 860 _work_list.at_put(insert_idx, cur); | |
| 861 | |
| 862 TRACE_LINEAR_SCAN(3, tty->print_cr("Sorted B%d into worklist. new worklist:", cur->block_id())); | |
| 863 TRACE_LINEAR_SCAN(3, for (int i = 0; i < _work_list.length(); i++) tty->print_cr("%8d B%2d weight:%6x", i, _work_list.at(i)->block_id(), _work_list.at(i)->linear_scan_number())); | |
| 864 | |
| 865 #ifdef ASSERT | |
| 866 for (int i = 0; i < _work_list.length(); i++) { | |
| 867 assert(_work_list.at(i)->linear_scan_number() > 0, "weight not set"); | |
| 868 assert(i == 0 || _work_list.at(i - 1)->linear_scan_number() <= _work_list.at(i)->linear_scan_number(), "incorrect order in worklist"); | |
| 869 } | |
| 870 #endif | |
| 871 } | |
| 872 | |
| 873 void ComputeLinearScanOrder::append_block(BlockBegin* cur) { | |
| 874 TRACE_LINEAR_SCAN(3, tty->print_cr("appending block B%d (weight 0x%6x) to linear-scan order", cur->block_id(), cur->linear_scan_number())); | |
| 875 assert(_linear_scan_order->index_of(cur) == -1, "cannot add the same block twice"); | |
| 876 | |
| 877 // currently, the linear scan order and code emit order are equal. | |
| 878 // therefore the linear_scan_number and the weight of a block must also | |
| 879 // be equal. | |
| 880 cur->set_linear_scan_number(_linear_scan_order->length()); | |
| 881 _linear_scan_order->append(cur); | |
| 882 } | |
| 883 | |
| 884 void ComputeLinearScanOrder::compute_order(BlockBegin* start_block) { | |
| 885 TRACE_LINEAR_SCAN(3, "----- computing final block order"); | |
| 886 | |
| 887 // the start block is always the first block in the linear scan order | |
| 888 _linear_scan_order = new BlockList(_num_blocks); | |
| 889 append_block(start_block); | |
| 890 | |
| 891 assert(start_block->end()->as_Base() != NULL, "start block must end with Base-instruction"); | |
| 892 BlockBegin* std_entry = ((Base*)start_block->end())->std_entry(); | |
| 893 BlockBegin* osr_entry = ((Base*)start_block->end())->osr_entry(); | |
| 894 | |
| 895 BlockBegin* sux_of_osr_entry = NULL; | |
| 896 if (osr_entry != NULL) { | |
| 897 // special handling for osr entry: | |
| 898 // ignore the edge between the osr entry and its successor for processing | |
| 899 // the osr entry block is added manually below | |
| 900 assert(osr_entry->number_of_sux() == 1, "osr entry must have exactly one successor"); | |
| 901 assert(osr_entry->sux_at(0)->number_of_preds() >= 2, "sucessor of osr entry must have two predecessors (otherwise it is not present in normal control flow"); | |
| 902 | |
| 903 sux_of_osr_entry = osr_entry->sux_at(0); | |
| 904 dec_forward_branches(sux_of_osr_entry); | |
| 905 | |
| 906 compute_dominator(osr_entry, start_block); | |
| 907 _iterative_dominators = true; | |
| 908 } | |
| 909 compute_dominator(std_entry, start_block); | |
| 910 | |
| 911 // start processing with standard entry block | |
| 912 assert(_work_list.is_empty(), "list must be empty before processing"); | |
| 913 | |
| 914 if (ready_for_processing(std_entry)) { | |
| 915 sort_into_work_list(std_entry); | |
| 916 } else { | |
| 917 assert(false, "the std_entry must be ready for processing (otherwise, the method has no start block)"); | |
| 918 } | |
| 919 | |
| 920 do { | |
| 921 BlockBegin* cur = _work_list.pop(); | |
| 922 | |
| 923 if (cur == sux_of_osr_entry) { | |
| 924 // the osr entry block is ignored in normal processing, it is never added to the | |
| 925 // work list. Instead, it is added as late as possible manually here. | |
| 926 append_block(osr_entry); | |
| 927 compute_dominator(cur, osr_entry); | |
| 928 } | |
| 929 append_block(cur); | |
| 930 | |
| 931 int i; | |
| 932 int num_sux = cur->number_of_sux(); | |
| 933 // changed loop order to get "intuitive" order of if- and else-blocks | |
| 934 for (i = 0; i < num_sux; i++) { | |
| 935 BlockBegin* sux = cur->sux_at(i); | |
| 936 compute_dominator(sux, cur); | |
| 937 if (ready_for_processing(sux)) { | |
| 938 sort_into_work_list(sux); | |
| 939 } | |
| 940 } | |
| 941 num_sux = cur->number_of_exception_handlers(); | |
| 942 for (i = 0; i < num_sux; i++) { | |
| 943 BlockBegin* sux = cur->exception_handler_at(i); | |
| 944 compute_dominator(sux, cur); | |
| 945 if (ready_for_processing(sux)) { | |
| 946 sort_into_work_list(sux); | |
| 947 } | |
| 948 } | |
| 949 } while (_work_list.length() > 0); | |
| 950 } | |
| 951 | |
| 952 | |
| 953 bool ComputeLinearScanOrder::compute_dominators_iter() { | |
| 954 bool changed = false; | |
| 955 int num_blocks = _linear_scan_order->length(); | |
| 956 | |
| 957 assert(_linear_scan_order->at(0)->dominator() == NULL, "must not have dominator"); | |
| 958 assert(_linear_scan_order->at(0)->number_of_preds() == 0, "must not have predecessors"); | |
| 959 for (int i = 1; i < num_blocks; i++) { | |
| 960 BlockBegin* block = _linear_scan_order->at(i); | |
| 961 | |
| 962 BlockBegin* dominator = block->pred_at(0); | |
| 963 int num_preds = block->number_of_preds(); | |
| 964 for (int i = 1; i < num_preds; i++) { | |
| 965 dominator = common_dominator(dominator, block->pred_at(i)); | |
| 966 } | |
| 967 | |
| 968 if (dominator != block->dominator()) { | |
| 969 TRACE_LINEAR_SCAN(4, tty->print_cr("DOM: updating dominator of B%d from B%d to B%d", block->block_id(), block->dominator()->block_id(), dominator->block_id())); | |
| 970 | |
| 971 block->set_dominator(dominator); | |
| 972 changed = true; | |
| 973 } | |
| 974 } | |
| 975 return changed; | |
| 976 } | |
| 977 | |
| 978 void ComputeLinearScanOrder::compute_dominators() { | |
| 979 TRACE_LINEAR_SCAN(3, tty->print_cr("----- computing dominators (iterative computation reqired: %d)", _iterative_dominators)); | |
| 980 | |
| 981 // iterative computation of dominators is only required for methods with non-natural loops | |
| 982 // and OSR-methods. For all other methods, the dominators computed when generating the | |
| 983 // linear scan block order are correct. | |
| 984 if (_iterative_dominators) { | |
| 985 do { | |
| 986 TRACE_LINEAR_SCAN(1, tty->print_cr("DOM: next iteration of fix-point calculation")); | |
| 987 } while (compute_dominators_iter()); | |
| 988 } | |
| 989 | |
| 990 // check that dominators are correct | |
| 991 assert(!compute_dominators_iter(), "fix point not reached"); | |
| 992 } | |
| 993 | |
| 994 | |
| 995 #ifndef PRODUCT | |
| 996 void ComputeLinearScanOrder::print_blocks() { | |
| 997 if (TraceLinearScanLevel >= 2) { | |
| 998 tty->print_cr("----- loop information:"); | |
| 999 for (int block_idx = 0; block_idx < _linear_scan_order->length(); block_idx++) { | |
| 1000 BlockBegin* cur = _linear_scan_order->at(block_idx); | |
| 1001 | |
| 1002 tty->print("%4d: B%2d: ", cur->linear_scan_number(), cur->block_id()); | |
| 1003 for (int loop_idx = 0; loop_idx < _num_loops; loop_idx++) { | |
| 1004 tty->print ("%d ", is_block_in_loop(loop_idx, cur)); | |
| 1005 } | |
| 1006 tty->print_cr(" -> loop_index: %2d, loop_depth: %2d", cur->loop_index(), cur->loop_depth()); | |
| 1007 } | |
| 1008 } | |
| 1009 | |
| 1010 if (TraceLinearScanLevel >= 1) { | |
| 1011 tty->print_cr("----- linear-scan block order:"); | |
| 1012 for (int block_idx = 0; block_idx < _linear_scan_order->length(); block_idx++) { | |
| 1013 BlockBegin* cur = _linear_scan_order->at(block_idx); | |
| 1014 tty->print("%4d: B%2d loop: %2d depth: %2d", cur->linear_scan_number(), cur->block_id(), cur->loop_index(), cur->loop_depth()); | |
| 1015 | |
| 1016 tty->print(cur->is_set(BlockBegin::exception_entry_flag) ? " ex" : " "); | |
| 1017 tty->print(cur->is_set(BlockBegin::critical_edge_split_flag) ? " ce" : " "); | |
| 1018 tty->print(cur->is_set(BlockBegin::linear_scan_loop_header_flag) ? " lh" : " "); | |
| 1019 tty->print(cur->is_set(BlockBegin::linear_scan_loop_end_flag) ? " le" : " "); | |
| 1020 | |
| 1021 if (cur->dominator() != NULL) { | |
| 1022 tty->print(" dom: B%d ", cur->dominator()->block_id()); | |
| 1023 } else { | |
| 1024 tty->print(" dom: NULL "); | |
| 1025 } | |
| 1026 | |
| 1027 if (cur->number_of_preds() > 0) { | |
| 1028 tty->print(" preds: "); | |
| 1029 for (int j = 0; j < cur->number_of_preds(); j++) { | |
| 1030 BlockBegin* pred = cur->pred_at(j); | |
| 1031 tty->print("B%d ", pred->block_id()); | |
| 1032 } | |
| 1033 } | |
| 1034 if (cur->number_of_sux() > 0) { | |
| 1035 tty->print(" sux: "); | |
| 1036 for (int j = 0; j < cur->number_of_sux(); j++) { | |
| 1037 BlockBegin* sux = cur->sux_at(j); | |
| 1038 tty->print("B%d ", sux->block_id()); | |
| 1039 } | |
| 1040 } | |
| 1041 if (cur->number_of_exception_handlers() > 0) { | |
| 1042 tty->print(" ex: "); | |
| 1043 for (int j = 0; j < cur->number_of_exception_handlers(); j++) { | |
| 1044 BlockBegin* ex = cur->exception_handler_at(j); | |
| 1045 tty->print("B%d ", ex->block_id()); | |
| 1046 } | |
| 1047 } | |
| 1048 tty->cr(); | |
| 1049 } | |
| 1050 } | |
| 1051 } | |
| 1052 #endif | |
| 1053 | |
| 1054 #ifdef ASSERT | |
| 1055 void ComputeLinearScanOrder::verify() { | |
| 1056 assert(_linear_scan_order->length() == _num_blocks, "wrong number of blocks in list"); | |
| 1057 | |
| 1058 if (StressLinearScan) { | |
| 1059 // blocks are scrambled when StressLinearScan is used | |
| 1060 return; | |
| 1061 } | |
| 1062 | |
| 1063 // check that all successors of a block have a higher linear-scan-number | |
| 1064 // and that all predecessors of a block have a lower linear-scan-number | |
| 1065 // (only backward branches of loops are ignored) | |
| 1066 int i; | |
| 1067 for (i = 0; i < _linear_scan_order->length(); i++) { | |
| 1068 BlockBegin* cur = _linear_scan_order->at(i); | |
| 1069 | |
| 1070 assert(cur->linear_scan_number() == i, "incorrect linear_scan_number"); | |
| 1071 assert(cur->linear_scan_number() >= 0 && cur->linear_scan_number() == _linear_scan_order->index_of(cur), "incorrect linear_scan_number"); | |
| 1072 | |
| 1073 int j; | |
| 1074 for (j = cur->number_of_sux() - 1; j >= 0; j--) { | |
| 1075 BlockBegin* sux = cur->sux_at(j); | |
| 1076 | |
| 1077 assert(sux->linear_scan_number() >= 0 && sux->linear_scan_number() == _linear_scan_order->index_of(sux), "incorrect linear_scan_number"); | |
| 1078 if (!cur->is_set(BlockBegin::linear_scan_loop_end_flag)) { | |
| 1079 assert(cur->linear_scan_number() < sux->linear_scan_number(), "invalid order"); | |
| 1080 } | |
| 1081 if (cur->loop_depth() == sux->loop_depth()) { | |
| 1082 assert(cur->loop_index() == sux->loop_index() || sux->is_set(BlockBegin::linear_scan_loop_header_flag), "successing blocks with same loop depth must have same loop index"); | |
| 1083 } | |
| 1084 } | |
| 1085 | |
| 1086 for (j = cur->number_of_preds() - 1; j >= 0; j--) { | |
| 1087 BlockBegin* pred = cur->pred_at(j); | |
| 1088 | |
| 1089 assert(pred->linear_scan_number() >= 0 && pred->linear_scan_number() == _linear_scan_order->index_of(pred), "incorrect linear_scan_number"); | |
| 1090 if (!cur->is_set(BlockBegin::linear_scan_loop_header_flag)) { | |
| 1091 assert(cur->linear_scan_number() > pred->linear_scan_number(), "invalid order"); | |
| 1092 } | |
| 1093 if (cur->loop_depth() == pred->loop_depth()) { | |
| 1094 assert(cur->loop_index() == pred->loop_index() || cur->is_set(BlockBegin::linear_scan_loop_header_flag), "successing blocks with same loop depth must have same loop index"); | |
| 1095 } | |
| 1096 | |
| 1097 assert(cur->dominator()->linear_scan_number() <= cur->pred_at(j)->linear_scan_number(), "dominator must be before predecessors"); | |
| 1098 } | |
| 1099 | |
| 1100 // check dominator | |
| 1101 if (i == 0) { | |
| 1102 assert(cur->dominator() == NULL, "first block has no dominator"); | |
| 1103 } else { | |
| 1104 assert(cur->dominator() != NULL, "all but first block must have dominator"); | |
| 1105 } | |
| 1106 assert(cur->number_of_preds() != 1 || cur->dominator() == cur->pred_at(0), "Single predecessor must also be dominator"); | |
| 1107 } | |
| 1108 | |
| 1109 // check that all loops are continuous | |
| 1110 for (int loop_idx = 0; loop_idx < _num_loops; loop_idx++) { | |
| 1111 int block_idx = 0; | |
| 1112 assert(!is_block_in_loop(loop_idx, _linear_scan_order->at(block_idx)), "the first block must not be present in any loop"); | |
| 1113 | |
| 1114 // skip blocks before the loop | |
| 1115 while (block_idx < _num_blocks && !is_block_in_loop(loop_idx, _linear_scan_order->at(block_idx))) { | |
| 1116 block_idx++; | |
| 1117 } | |
| 1118 // skip blocks of loop | |
| 1119 while (block_idx < _num_blocks && is_block_in_loop(loop_idx, _linear_scan_order->at(block_idx))) { | |
| 1120 block_idx++; | |
| 1121 } | |
| 1122 // after the first non-loop block, there must not be another loop-block | |
| 1123 while (block_idx < _num_blocks) { | |
| 1124 assert(!is_block_in_loop(loop_idx, _linear_scan_order->at(block_idx)), "loop not continuous in linear-scan order"); | |
| 1125 block_idx++; | |
| 1126 } | |
| 1127 } | |
| 1128 } | |
| 1129 #endif | |
| 1130 | |
| 1131 | |
| 1132 void IR::compute_code() { | |
| 1133 assert(is_valid(), "IR must be valid"); | |
| 1134 | |
| 1135 ComputeLinearScanOrder compute_order(start()); | |
| 1136 _num_loops = compute_order.num_loops(); | |
| 1137 _code = compute_order.linear_scan_order(); | |
| 1138 } | |
| 1139 | |
| 1140 | |
| 1141 void IR::compute_use_counts() { | |
| 1142 // make sure all values coming out of this block get evaluated. | |
| 1143 int num_blocks = _code->length(); | |
| 1144 for (int i = 0; i < num_blocks; i++) { | |
| 1145 _code->at(i)->end()->state()->pin_stack_for_linear_scan(); | |
| 1146 } | |
| 1147 | |
| 1148 // compute use counts | |
| 1149 UseCountComputer::compute(_code); | |
| 1150 } | |
| 1151 | |
| 1152 | |
| 1153 void IR::iterate_preorder(BlockClosure* closure) { | |
| 1154 assert(is_valid(), "IR must be valid"); | |
| 1155 start()->iterate_preorder(closure); | |
| 1156 } | |
| 1157 | |
| 1158 | |
| 1159 void IR::iterate_postorder(BlockClosure* closure) { | |
| 1160 assert(is_valid(), "IR must be valid"); | |
| 1161 start()->iterate_postorder(closure); | |
| 1162 } | |
| 1163 | |
| 1164 void IR::iterate_linear_scan_order(BlockClosure* closure) { | |
| 1165 linear_scan_order()->iterate_forward(closure); | |
| 1166 } | |
| 1167 | |
| 1168 | |
| 1169 #ifndef PRODUCT | |
| 1170 class BlockPrinter: public BlockClosure { | |
| 1171 private: | |
| 1172 InstructionPrinter* _ip; | |
| 1173 bool _cfg_only; | |
| 1174 bool _live_only; | |
| 1175 | |
| 1176 public: | |
| 1177 BlockPrinter(InstructionPrinter* ip, bool cfg_only, bool live_only = false) { | |
| 1178 _ip = ip; | |
| 1179 _cfg_only = cfg_only; | |
| 1180 _live_only = live_only; | |
| 1181 } | |
| 1182 | |
| 1183 virtual void block_do(BlockBegin* block) { | |
| 1184 if (_cfg_only) { | |
| 1185 _ip->print_instr(block); tty->cr(); | |
| 1186 } else { | |
| 1187 block->print_block(*_ip, _live_only); | |
| 1188 } | |
| 1189 } | |
| 1190 }; | |
| 1191 | |
| 1192 | |
| 1193 void IR::print(BlockBegin* start, bool cfg_only, bool live_only) { | |
| 1194 ttyLocker ttyl; | |
| 1195 InstructionPrinter ip(!cfg_only); | |
| 1196 BlockPrinter bp(&ip, cfg_only, live_only); | |
| 1197 start->iterate_preorder(&bp); | |
| 1198 tty->cr(); | |
| 1199 } | |
| 1200 | |
| 1201 void IR::print(bool cfg_only, bool live_only) { | |
| 1202 if (is_valid()) { | |
| 1203 print(start(), cfg_only, live_only); | |
| 1204 } else { | |
| 1205 tty->print_cr("invalid IR"); | |
| 1206 } | |
| 1207 } | |
| 1208 | |
| 1209 | |
| 1210 define_array(BlockListArray, BlockList*) | |
| 1211 define_stack(BlockListList, BlockListArray) | |
| 1212 | |
| 1213 class PredecessorValidator : public BlockClosure { | |
| 1214 private: | |
| 1215 BlockListList* _predecessors; | |
| 1216 BlockList* _blocks; | |
| 1217 | |
| 1218 static int cmp(BlockBegin** a, BlockBegin** b) { | |
| 1219 return (*a)->block_id() - (*b)->block_id(); | |
| 1220 } | |
| 1221 | |
| 1222 public: | |
| 1223 PredecessorValidator(IR* hir) { | |
| 1224 ResourceMark rm; | |
| 1225 _predecessors = new BlockListList(BlockBegin::number_of_blocks(), NULL); | |
| 1226 _blocks = new BlockList(); | |
| 1227 | |
| 1228 int i; | |
| 1229 hir->start()->iterate_preorder(this); | |
| 1230 if (hir->code() != NULL) { | |
| 1231 assert(hir->code()->length() == _blocks->length(), "must match"); | |
| 1232 for (i = 0; i < _blocks->length(); i++) { | |
| 1233 assert(hir->code()->contains(_blocks->at(i)), "should be in both lists"); | |
| 1234 } | |
| 1235 } | |
| 1236 | |
| 1237 for (i = 0; i < _blocks->length(); i++) { | |
| 1238 BlockBegin* block = _blocks->at(i); | |
| 1239 BlockList* preds = _predecessors->at(block->block_id()); | |
| 1240 if (preds == NULL) { | |
| 1241 assert(block->number_of_preds() == 0, "should be the same"); | |
| 1242 continue; | |
| 1243 } | |
| 1244 | |
| 1245 // clone the pred list so we can mutate it | |
| 1246 BlockList* pred_copy = new BlockList(); | |
| 1247 int j; | |
| 1248 for (j = 0; j < block->number_of_preds(); j++) { | |
| 1249 pred_copy->append(block->pred_at(j)); | |
| 1250 } | |
| 1251 // sort them in the same order | |
| 1252 preds->sort(cmp); | |
| 1253 pred_copy->sort(cmp); | |
| 1254 int length = MIN2(preds->length(), block->number_of_preds()); | |
| 1255 for (j = 0; j < block->number_of_preds(); j++) { | |
| 1256 assert(preds->at(j) == pred_copy->at(j), "must match"); | |
| 1257 } | |
| 1258 | |
| 1259 assert(preds->length() == block->number_of_preds(), "should be the same"); | |
| 1260 } | |
| 1261 } | |
| 1262 | |
| 1263 virtual void block_do(BlockBegin* block) { | |
| 1264 _blocks->append(block); | |
| 1265 BlockEnd* be = block->end(); | |
| 1266 int n = be->number_of_sux(); | |
| 1267 int i; | |
| 1268 for (i = 0; i < n; i++) { | |
| 1269 BlockBegin* sux = be->sux_at(i); | |
| 1270 assert(!sux->is_set(BlockBegin::exception_entry_flag), "must not be xhandler"); | |
| 1271 | |
| 1272 BlockList* preds = _predecessors->at_grow(sux->block_id(), NULL); | |
| 1273 if (preds == NULL) { | |
| 1274 preds = new BlockList(); | |
| 1275 _predecessors->at_put(sux->block_id(), preds); | |
| 1276 } | |
| 1277 preds->append(block); | |
| 1278 } | |
| 1279 | |
| 1280 n = block->number_of_exception_handlers(); | |
| 1281 for (i = 0; i < n; i++) { | |
| 1282 BlockBegin* sux = block->exception_handler_at(i); | |
| 1283 assert(sux->is_set(BlockBegin::exception_entry_flag), "must be xhandler"); | |
| 1284 | |
| 1285 BlockList* preds = _predecessors->at_grow(sux->block_id(), NULL); | |
| 1286 if (preds == NULL) { | |
| 1287 preds = new BlockList(); | |
| 1288 _predecessors->at_put(sux->block_id(), preds); | |
| 1289 } | |
| 1290 preds->append(block); | |
| 1291 } | |
| 1292 } | |
| 1293 }; | |
| 1294 | |
| 1295 void IR::verify() { | |
| 1296 #ifdef ASSERT | |
| 1297 PredecessorValidator pv(this); | |
| 1298 #endif | |
| 1299 } | |
| 1300 | |
| 1301 #endif // PRODUCT | |
| 1302 | |
| 1303 void SubstitutionResolver::substitute(Value* v) { | |
| 1304 Value v0 = *v; | |
| 1305 if (v0) { | |
| 1306 Value vs = v0->subst(); | |
| 1307 if (vs != v0) { | |
| 1308 *v = v0->subst(); | |
| 1309 } | |
| 1310 } | |
| 1311 } | |
| 1312 | |
| 1313 #ifdef ASSERT | |
| 1314 void check_substitute(Value* v) { | |
| 1315 Value v0 = *v; | |
| 1316 if (v0) { | |
| 1317 Value vs = v0->subst(); | |
| 1318 assert(vs == v0, "missed substitution"); | |
| 1319 } | |
| 1320 } | |
| 1321 #endif | |
| 1322 | |
| 1323 | |
| 1324 void SubstitutionResolver::block_do(BlockBegin* block) { | |
| 1325 Instruction* last = NULL; | |
| 1326 for (Instruction* n = block; n != NULL;) { | |
| 1327 n->values_do(substitute); | |
| 1328 // need to remove this instruction from the instruction stream | |
| 1329 if (n->subst() != n) { | |
| 1330 assert(last != NULL, "must have last"); | |
| 1331 last->set_next(n->next(), n->next()->bci()); | |
| 1332 } else { | |
| 1333 last = n; | |
| 1334 } | |
| 1335 n = last->next(); | |
| 1336 } | |
| 1337 | |
| 1338 #ifdef ASSERT | |
| 1339 if (block->state()) block->state()->values_do(check_substitute); | |
| 1340 block->block_values_do(check_substitute); | |
| 1341 if (block->end() && block->end()->state()) block->end()->state()->values_do(check_substitute); | |
| 1342 #endif | |
| 1343 } |