Mercurial > hg > truffle
annotate src/share/vm/c1/c1_IR.cpp @ 8860:46f6f063b272
7153771: array bound check elimination for c1
Summary: when possible optimize out array bound checks, inserting predicates when needed.
Reviewed-by: never, kvn, twisti
Contributed-by: thomaswue <thomas.wuerthinger@oracle.com>
| author | roland |
|---|---|
| date | Thu, 21 Mar 2013 09:27:54 +0100 |
| parents | b9a9ed0f8eeb |
| children | b9a918201d47 ef57c43512d6 |
| rev | line source |
|---|---|
| 0 | 1 /* |
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2 * Copyright (c) 1999, 2012, Oracle and/or its affiliates. All rights reserved. |
| 0 | 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 4 * | |
| 5 * This code is free software; you can redistribute it and/or modify it | |
| 6 * under the terms of the GNU General Public License version 2 only, as | |
| 7 * published by the Free Software Foundation. | |
| 8 * | |
| 9 * This code is distributed in the hope that it will be useful, but WITHOUT | |
| 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
| 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
| 12 * version 2 for more details (a copy is included in the LICENSE file that | |
| 13 * accompanied this code). | |
| 14 * | |
| 15 * You should have received a copy of the GNU General Public License version | |
| 16 * 2 along with this work; if not, write to the Free Software Foundation, | |
| 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | |
| 18 * | |
|
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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20 * or visit www.oracle.com if you need additional information or have any |
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21 * questions. |
| 0 | 22 * |
| 23 */ | |
| 24 | |
| 1972 | 25 #include "precompiled.hpp" |
| 26 #include "c1/c1_Compilation.hpp" | |
| 27 #include "c1/c1_FrameMap.hpp" | |
| 28 #include "c1/c1_GraphBuilder.hpp" | |
| 29 #include "c1/c1_IR.hpp" | |
| 30 #include "c1/c1_InstructionPrinter.hpp" | |
| 31 #include "c1/c1_Optimizer.hpp" | |
| 32 #include "utilities/bitMap.inline.hpp" | |
| 0 | 33 |
| 34 | |
| 35 // Implementation of XHandlers | |
| 36 // | |
| 37 // Note: This code could eventually go away if we are | |
| 38 // just using the ciExceptionHandlerStream. | |
| 39 | |
| 40 XHandlers::XHandlers(ciMethod* method) : _list(method->exception_table_length()) { | |
| 41 ciExceptionHandlerStream s(method); | |
| 42 while (!s.is_done()) { | |
| 43 _list.append(new XHandler(s.handler())); | |
| 44 s.next(); | |
| 45 } | |
| 46 assert(s.count() == method->exception_table_length(), "exception table lengths inconsistent"); | |
| 47 } | |
| 48 | |
| 49 // deep copy of all XHandler contained in list | |
| 50 XHandlers::XHandlers(XHandlers* other) : | |
| 51 _list(other->length()) | |
| 52 { | |
| 53 for (int i = 0; i < other->length(); i++) { | |
| 54 _list.append(new XHandler(other->handler_at(i))); | |
| 55 } | |
| 56 } | |
| 57 | |
| 58 // Returns whether a particular exception type can be caught. Also | |
| 59 // returns true if klass is unloaded or any exception handler | |
| 60 // classes are unloaded. type_is_exact indicates whether the throw | |
| 61 // is known to be exactly that class or it might throw a subtype. | |
| 62 bool XHandlers::could_catch(ciInstanceKlass* klass, bool type_is_exact) const { | |
| 63 // the type is unknown so be conservative | |
| 64 if (!klass->is_loaded()) { | |
| 65 return true; | |
| 66 } | |
| 67 | |
| 68 for (int i = 0; i < length(); i++) { | |
| 69 XHandler* handler = handler_at(i); | |
| 70 if (handler->is_catch_all()) { | |
| 71 // catch of ANY | |
| 72 return true; | |
| 73 } | |
| 74 ciInstanceKlass* handler_klass = handler->catch_klass(); | |
| 75 // if it's unknown it might be catchable | |
| 76 if (!handler_klass->is_loaded()) { | |
| 77 return true; | |
| 78 } | |
| 79 // if the throw type is definitely a subtype of the catch type | |
| 80 // then it can be caught. | |
| 81 if (klass->is_subtype_of(handler_klass)) { | |
| 82 return true; | |
| 83 } | |
| 84 if (!type_is_exact) { | |
| 85 // If the type isn't exactly known then it can also be caught by | |
| 86 // catch statements where the inexact type is a subtype of the | |
| 87 // catch type. | |
| 88 // given: foo extends bar extends Exception | |
| 89 // throw bar can be caught by catch foo, catch bar, and catch | |
| 90 // Exception, however it can't be caught by any handlers without | |
| 91 // bar in its type hierarchy. | |
| 92 if (handler_klass->is_subtype_of(klass)) { | |
| 93 return true; | |
| 94 } | |
| 95 } | |
| 96 } | |
| 97 | |
| 98 return false; | |
| 99 } | |
| 100 | |
| 101 | |
| 102 bool XHandlers::equals(XHandlers* others) const { | |
| 103 if (others == NULL) return false; | |
| 104 if (length() != others->length()) return false; | |
| 105 | |
| 106 for (int i = 0; i < length(); i++) { | |
| 107 if (!handler_at(i)->equals(others->handler_at(i))) return false; | |
| 108 } | |
| 109 return true; | |
| 110 } | |
| 111 | |
| 112 bool XHandler::equals(XHandler* other) const { | |
| 113 assert(entry_pco() != -1 && other->entry_pco() != -1, "must have entry_pco"); | |
| 114 | |
| 115 if (entry_pco() != other->entry_pco()) return false; | |
| 116 if (scope_count() != other->scope_count()) return false; | |
| 117 if (_desc != other->_desc) return false; | |
| 118 | |
| 119 assert(entry_block() == other->entry_block(), "entry_block must be equal when entry_pco is equal"); | |
| 120 return true; | |
| 121 } | |
| 122 | |
| 123 | |
| 124 // Implementation of IRScope | |
| 125 BlockBegin* IRScope::build_graph(Compilation* compilation, int osr_bci) { | |
| 126 GraphBuilder gm(compilation, this); | |
| 127 NOT_PRODUCT(if (PrintValueNumbering && Verbose) gm.print_stats()); | |
| 128 if (compilation->bailed_out()) return NULL; | |
| 129 return gm.start(); | |
| 130 } | |
| 131 | |
| 132 | |
| 133 IRScope::IRScope(Compilation* compilation, IRScope* caller, int caller_bci, ciMethod* method, int osr_bci, bool create_graph) | |
| 134 : _callees(2) | |
| 135 , _compilation(compilation) | |
| 136 , _requires_phi_function(method->max_locals()) | |
| 137 { | |
| 138 _caller = caller; | |
| 139 _level = caller == NULL ? 0 : caller->level() + 1; | |
| 140 _method = method; | |
| 141 _xhandlers = new XHandlers(method); | |
| 142 _number_of_locks = 0; | |
| 143 _monitor_pairing_ok = method->has_balanced_monitors(); | |
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144 _wrote_final = false; |
| 0 | 145 _start = NULL; |
| 146 | |
| 147 if (osr_bci == -1) { | |
| 148 _requires_phi_function.clear(); | |
| 149 } else { | |
| 150 // selective creation of phi functions is not possibel in osr-methods | |
| 151 _requires_phi_function.set_range(0, method->max_locals()); | |
| 152 } | |
| 153 | |
| 154 assert(method->holder()->is_loaded() , "method holder must be loaded"); | |
| 155 | |
| 156 // build graph if monitor pairing is ok | |
| 157 if (create_graph && monitor_pairing_ok()) _start = build_graph(compilation, osr_bci); | |
| 158 } | |
| 159 | |
| 160 | |
| 161 int IRScope::max_stack() const { | |
| 162 int my_max = method()->max_stack(); | |
| 163 int callee_max = 0; | |
| 164 for (int i = 0; i < number_of_callees(); i++) { | |
| 165 callee_max = MAX2(callee_max, callee_no(i)->max_stack()); | |
| 166 } | |
| 167 return my_max + callee_max; | |
| 168 } | |
| 169 | |
| 170 | |
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171 bool IRScopeDebugInfo::should_reexecute() { |
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172 ciMethod* cur_method = scope()->method(); |
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173 int cur_bci = bci(); |
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174 if (cur_method != NULL && cur_bci != SynchronizationEntryBCI) { |
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175 Bytecodes::Code code = cur_method->java_code_at_bci(cur_bci); |
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176 return Interpreter::bytecode_should_reexecute(code); |
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177 } else |
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178 return false; |
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179 } |
| 0 | 180 |
| 181 | |
| 182 // Implementation of CodeEmitInfo | |
| 183 | |
| 184 // Stack must be NON-null | |
| 8860 | 185 CodeEmitInfo::CodeEmitInfo(ValueStack* stack, XHandlers* exception_handlers, bool deoptimize_on_exception) |
| 0 | 186 : _scope(stack->scope()) |
| 187 , _scope_debug_info(NULL) | |
| 188 , _oop_map(NULL) | |
| 189 , _stack(stack) | |
| 190 , _exception_handlers(exception_handlers) | |
| 8860 | 191 , _is_method_handle_invoke(false) |
| 192 , _deoptimize_on_exception(deoptimize_on_exception) { | |
| 0 | 193 assert(_stack != NULL, "must be non null"); |
| 194 } | |
| 195 | |
| 196 | |
| 1819 | 197 CodeEmitInfo::CodeEmitInfo(CodeEmitInfo* info, ValueStack* stack) |
| 0 | 198 : _scope(info->_scope) |
| 199 , _exception_handlers(NULL) | |
| 200 , _scope_debug_info(NULL) | |
| 1564 | 201 , _oop_map(NULL) |
| 1819 | 202 , _stack(stack == NULL ? info->_stack : stack) |
| 8860 | 203 , _is_method_handle_invoke(info->_is_method_handle_invoke) |
| 204 , _deoptimize_on_exception(info->_deoptimize_on_exception) { | |
| 0 | 205 |
| 206 // deep copy of exception handlers | |
| 207 if (info->_exception_handlers != NULL) { | |
| 208 _exception_handlers = new XHandlers(info->_exception_handlers); | |
| 209 } | |
| 210 } | |
| 211 | |
| 212 | |
| 1564 | 213 void CodeEmitInfo::record_debug_info(DebugInformationRecorder* recorder, int pc_offset) { |
| 0 | 214 // record the safepoint before recording the debug info for enclosing scopes |
| 215 recorder->add_safepoint(pc_offset, _oop_map->deep_copy()); | |
| 1564 | 216 _scope_debug_info->record_debug_info(recorder, pc_offset, true/*topmost*/, _is_method_handle_invoke); |
| 0 | 217 recorder->end_safepoint(pc_offset); |
| 218 } | |
| 219 | |
| 220 | |
| 221 void CodeEmitInfo::add_register_oop(LIR_Opr opr) { | |
| 222 assert(_oop_map != NULL, "oop map must already exist"); | |
| 223 assert(opr->is_single_cpu(), "should not call otherwise"); | |
| 224 | |
| 225 VMReg name = frame_map()->regname(opr); | |
| 226 _oop_map->set_oop(name); | |
| 227 } | |
| 228 | |
| 229 | |
| 230 | |
| 231 | |
| 232 // Implementation of IR | |
| 233 | |
| 234 IR::IR(Compilation* compilation, ciMethod* method, int osr_bci) : | |
| 235 _locals_size(in_WordSize(-1)) | |
| 236 , _num_loops(0) { | |
| 237 // setup IR fields | |
| 238 _compilation = compilation; | |
| 239 _top_scope = new IRScope(compilation, NULL, -1, method, osr_bci, true); | |
| 240 _code = NULL; | |
| 241 } | |
| 242 | |
| 243 | |
| 8860 | 244 void IR::optimize_blocks() { |
| 0 | 245 Optimizer opt(this); |
| 1783 | 246 if (!compilation()->profile_branches()) { |
| 247 if (DoCEE) { | |
| 248 opt.eliminate_conditional_expressions(); | |
| 0 | 249 #ifndef PRODUCT |
| 1783 | 250 if (PrintCFG || PrintCFG1) { tty->print_cr("CFG after CEE"); print(true); } |
| 251 if (PrintIR || PrintIR1 ) { tty->print_cr("IR after CEE"); print(false); } | |
| 0 | 252 #endif |
| 1783 | 253 } |
| 254 if (EliminateBlocks) { | |
| 255 opt.eliminate_blocks(); | |
| 0 | 256 #ifndef PRODUCT |
| 1783 | 257 if (PrintCFG || PrintCFG1) { tty->print_cr("CFG after block elimination"); print(true); } |
| 258 if (PrintIR || PrintIR1 ) { tty->print_cr("IR after block elimination"); print(false); } | |
| 0 | 259 #endif |
| 1783 | 260 } |
| 0 | 261 } |
| 8860 | 262 } |
| 263 | |
| 264 void IR::eliminate_null_checks() { | |
| 265 Optimizer opt(this); | |
| 0 | 266 if (EliminateNullChecks) { |
| 267 opt.eliminate_null_checks(); | |
| 268 #ifndef PRODUCT | |
| 269 if (PrintCFG || PrintCFG1) { tty->print_cr("CFG after null check elimination"); print(true); } | |
| 270 if (PrintIR || PrintIR1 ) { tty->print_cr("IR after null check elimination"); print(false); } | |
| 271 #endif | |
| 272 } | |
| 273 } | |
| 274 | |
| 275 | |
| 276 static int sort_pairs(BlockPair** a, BlockPair** b) { | |
| 277 if ((*a)->from() == (*b)->from()) { | |
| 278 return (*a)->to()->block_id() - (*b)->to()->block_id(); | |
| 279 } else { | |
| 280 return (*a)->from()->block_id() - (*b)->from()->block_id(); | |
| 281 } | |
| 282 } | |
| 283 | |
| 284 | |
| 285 class CriticalEdgeFinder: public BlockClosure { | |
| 286 BlockPairList blocks; | |
| 287 IR* _ir; | |
| 288 | |
| 289 public: | |
| 290 CriticalEdgeFinder(IR* ir): _ir(ir) {} | |
| 291 void block_do(BlockBegin* bb) { | |
| 292 BlockEnd* be = bb->end(); | |
| 293 int nos = be->number_of_sux(); | |
| 294 if (nos >= 2) { | |
| 295 for (int i = 0; i < nos; i++) { | |
| 296 BlockBegin* sux = be->sux_at(i); | |
| 297 if (sux->number_of_preds() >= 2) { | |
| 298 blocks.append(new BlockPair(bb, sux)); | |
| 299 } | |
| 300 } | |
| 301 } | |
| 302 } | |
| 303 | |
| 304 void split_edges() { | |
| 305 BlockPair* last_pair = NULL; | |
| 306 blocks.sort(sort_pairs); | |
| 307 for (int i = 0; i < blocks.length(); i++) { | |
| 308 BlockPair* pair = blocks.at(i); | |
| 309 if (last_pair != NULL && pair->is_same(last_pair)) continue; | |
| 310 BlockBegin* from = pair->from(); | |
| 311 BlockBegin* to = pair->to(); | |
| 312 BlockBegin* split = from->insert_block_between(to); | |
| 313 #ifndef PRODUCT | |
| 314 if ((PrintIR || PrintIR1) && Verbose) { | |
| 315 tty->print_cr("Split critical edge B%d -> B%d (new block B%d)", | |
| 316 from->block_id(), to->block_id(), split->block_id()); | |
| 317 } | |
| 318 #endif | |
| 319 last_pair = pair; | |
| 320 } | |
| 321 } | |
| 322 }; | |
| 323 | |
| 324 void IR::split_critical_edges() { | |
| 325 CriticalEdgeFinder cef(this); | |
| 326 | |
| 327 iterate_preorder(&cef); | |
| 328 cef.split_edges(); | |
| 329 } | |
| 330 | |
| 331 | |
| 1584 | 332 class UseCountComputer: public ValueVisitor, BlockClosure { |
| 0 | 333 private: |
| 1584 | 334 void visit(Value* n) { |
| 0 | 335 // Local instructions and Phis for expression stack values at the |
| 336 // start of basic blocks are not added to the instruction list | |
| 1899 | 337 if (!(*n)->is_linked() && (*n)->can_be_linked()) { |
| 0 | 338 assert(false, "a node was not appended to the graph"); |
| 1584 | 339 Compilation::current()->bailout("a node was not appended to the graph"); |
| 0 | 340 } |
| 341 // use n's input if not visited before | |
| 342 if (!(*n)->is_pinned() && !(*n)->has_uses()) { | |
| 343 // note: a) if the instruction is pinned, it will be handled by compute_use_count | |
| 344 // b) if the instruction has uses, it was touched before | |
| 345 // => in both cases we don't need to update n's values | |
| 346 uses_do(n); | |
| 347 } | |
| 348 // use n | |
| 349 (*n)->_use_count++; | |
| 350 } | |
| 351 | |
| 1584 | 352 Values* worklist; |
| 353 int depth; | |
| 0 | 354 enum { |
| 355 max_recurse_depth = 20 | |
| 356 }; | |
| 357 | |
| 1584 | 358 void uses_do(Value* n) { |
| 0 | 359 depth++; |
| 360 if (depth > max_recurse_depth) { | |
| 361 // don't allow the traversal to recurse too deeply | |
| 362 worklist->push(*n); | |
| 363 } else { | |
| 1584 | 364 (*n)->input_values_do(this); |
| 0 | 365 // special handling for some instructions |
| 366 if ((*n)->as_BlockEnd() != NULL) { | |
| 367 // note on BlockEnd: | |
| 368 // must 'use' the stack only if the method doesn't | |
| 369 // terminate, however, in those cases stack is empty | |
| 1584 | 370 (*n)->state_values_do(this); |
| 0 | 371 } |
| 372 } | |
| 373 depth--; | |
| 374 } | |
| 375 | |
| 1584 | 376 void block_do(BlockBegin* b) { |
| 0 | 377 depth = 0; |
| 378 // process all pinned nodes as the roots of expression trees | |
| 379 for (Instruction* n = b; n != NULL; n = n->next()) { | |
| 380 if (n->is_pinned()) uses_do(&n); | |
| 381 } | |
| 382 assert(depth == 0, "should have counted back down"); | |
| 383 | |
| 384 // now process any unpinned nodes which recursed too deeply | |
| 385 while (worklist->length() > 0) { | |
| 386 Value t = worklist->pop(); | |
| 387 if (!t->is_pinned()) { | |
| 388 // compute the use count | |
| 389 uses_do(&t); | |
| 390 | |
| 391 // pin the instruction so that LIRGenerator doesn't recurse | |
| 392 // too deeply during it's evaluation. | |
| 393 t->pin(); | |
| 394 } | |
| 395 } | |
| 396 assert(depth == 0, "should have counted back down"); | |
| 397 } | |
| 398 | |
| 1584 | 399 UseCountComputer() { |
| 400 worklist = new Values(); | |
| 401 depth = 0; | |
| 402 } | |
| 403 | |
| 0 | 404 public: |
| 405 static void compute(BlockList* blocks) { | |
| 1584 | 406 UseCountComputer ucc; |
| 407 blocks->iterate_backward(&ucc); | |
| 0 | 408 } |
| 409 }; | |
| 410 | |
| 411 | |
| 412 // helper macro for short definition of trace-output inside code | |
| 413 #ifndef PRODUCT | |
| 414 #define TRACE_LINEAR_SCAN(level, code) \ | |
| 415 if (TraceLinearScanLevel >= level) { \ | |
| 416 code; \ | |
| 417 } | |
| 418 #else | |
| 419 #define TRACE_LINEAR_SCAN(level, code) | |
| 420 #endif | |
| 421 | |
| 422 class ComputeLinearScanOrder : public StackObj { | |
| 423 private: | |
| 424 int _max_block_id; // the highest block_id of a block | |
| 425 int _num_blocks; // total number of blocks (smaller than _max_block_id) | |
| 426 int _num_loops; // total number of loops | |
| 427 bool _iterative_dominators;// method requires iterative computation of dominatiors | |
| 428 | |
| 429 BlockList* _linear_scan_order; // the resulting list of blocks in correct order | |
| 430 | |
| 431 BitMap _visited_blocks; // used for recursive processing of blocks | |
| 432 BitMap _active_blocks; // used for recursive processing of blocks | |
| 433 BitMap _dominator_blocks; // temproary BitMap used for computation of dominator | |
| 434 intArray _forward_branches; // number of incoming forward branches for each block | |
| 435 BlockList _loop_end_blocks; // list of all loop end blocks collected during count_edges | |
| 436 BitMap2D _loop_map; // two-dimensional bit set: a bit is set if a block is contained in a loop | |
| 437 BlockList _work_list; // temporary list (used in mark_loops and compute_order) | |
| 8860 | 438 BlockList _loop_headers; |
| 0 | 439 |
| 1783 | 440 Compilation* _compilation; |
| 441 | |
| 0 | 442 // accessors for _visited_blocks and _active_blocks |
| 443 void init_visited() { _active_blocks.clear(); _visited_blocks.clear(); } | |
| 444 bool is_visited(BlockBegin* b) const { return _visited_blocks.at(b->block_id()); } | |
| 445 bool is_active(BlockBegin* b) const { return _active_blocks.at(b->block_id()); } | |
| 446 void set_visited(BlockBegin* b) { assert(!is_visited(b), "already set"); _visited_blocks.set_bit(b->block_id()); } | |
| 447 void set_active(BlockBegin* b) { assert(!is_active(b), "already set"); _active_blocks.set_bit(b->block_id()); } | |
| 448 void clear_active(BlockBegin* b) { assert(is_active(b), "not already"); _active_blocks.clear_bit(b->block_id()); } | |
| 449 | |
| 450 // accessors for _forward_branches | |
| 451 void inc_forward_branches(BlockBegin* b) { _forward_branches.at_put(b->block_id(), _forward_branches.at(b->block_id()) + 1); } | |
| 452 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()); } | |
| 453 | |
| 454 // accessors for _loop_map | |
| 455 bool is_block_in_loop (int loop_idx, BlockBegin* b) const { return _loop_map.at(loop_idx, b->block_id()); } | |
| 456 void set_block_in_loop (int loop_idx, BlockBegin* b) { _loop_map.set_bit(loop_idx, b->block_id()); } | |
| 457 void clear_block_in_loop(int loop_idx, int block_id) { _loop_map.clear_bit(loop_idx, block_id); } | |
| 458 | |
| 459 // count edges between blocks | |
| 460 void count_edges(BlockBegin* cur, BlockBegin* parent); | |
| 461 | |
| 462 // loop detection | |
| 463 void mark_loops(); | |
| 464 void clear_non_natural_loops(BlockBegin* start_block); | |
| 465 void assign_loop_depth(BlockBegin* start_block); | |
| 466 | |
| 467 // computation of final block order | |
| 468 BlockBegin* common_dominator(BlockBegin* a, BlockBegin* b); | |
| 469 void compute_dominator(BlockBegin* cur, BlockBegin* parent); | |
| 470 int compute_weight(BlockBegin* cur); | |
| 471 bool ready_for_processing(BlockBegin* cur); | |
| 472 void sort_into_work_list(BlockBegin* b); | |
| 473 void append_block(BlockBegin* cur); | |
| 474 void compute_order(BlockBegin* start_block); | |
| 475 | |
| 476 // fixup of dominators for non-natural loops | |
| 477 bool compute_dominators_iter(); | |
| 478 void compute_dominators(); | |
| 479 | |
| 480 // debug functions | |
| 481 NOT_PRODUCT(void print_blocks();) | |
| 482 DEBUG_ONLY(void verify();) | |
| 483 | |
| 1783 | 484 Compilation* compilation() const { return _compilation; } |
| 0 | 485 public: |
| 1783 | 486 ComputeLinearScanOrder(Compilation* c, BlockBegin* start_block); |
| 0 | 487 |
| 488 // accessors for final result | |
| 489 BlockList* linear_scan_order() const { return _linear_scan_order; } | |
| 490 int num_loops() const { return _num_loops; } | |
| 491 }; | |
| 492 | |
| 493 | |
| 1783 | 494 ComputeLinearScanOrder::ComputeLinearScanOrder(Compilation* c, BlockBegin* start_block) : |
| 0 | 495 _max_block_id(BlockBegin::number_of_blocks()), |
| 496 _num_blocks(0), | |
| 497 _num_loops(0), | |
| 498 _iterative_dominators(false), | |
| 499 _visited_blocks(_max_block_id), | |
| 500 _active_blocks(_max_block_id), | |
| 501 _dominator_blocks(_max_block_id), | |
| 502 _forward_branches(_max_block_id, 0), | |
| 503 _loop_end_blocks(8), | |
| 504 _work_list(8), | |
| 505 _linear_scan_order(NULL), // initialized later with correct size | |
| 1783 | 506 _loop_map(0, 0), // initialized later with correct size |
| 507 _compilation(c) | |
| 0 | 508 { |
| 509 TRACE_LINEAR_SCAN(2, "***** computing linear-scan block order"); | |
| 510 | |
| 511 init_visited(); | |
| 512 count_edges(start_block, NULL); | |
| 513 | |
| 1783 | 514 if (compilation()->is_profiling()) { |
|
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515 ciMethod *method = compilation()->method(); |
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516 if (!method->is_accessor()) { |
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517 ciMethodData* md = method->method_data_or_null(); |
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518 assert(md != NULL, "Sanity"); |
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519 md->set_compilation_stats(_num_loops, _num_blocks); |
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520 } |
| 1783 | 521 } |
| 522 | |
| 0 | 523 if (_num_loops > 0) { |
| 524 mark_loops(); | |
| 525 clear_non_natural_loops(start_block); | |
| 526 assign_loop_depth(start_block); | |
| 527 } | |
| 528 | |
| 529 compute_order(start_block); | |
| 530 compute_dominators(); | |
| 531 | |
| 532 NOT_PRODUCT(print_blocks()); | |
| 533 DEBUG_ONLY(verify()); | |
| 534 } | |
| 535 | |
| 536 | |
| 537 // Traverse the CFG: | |
| 538 // * count total number of blocks | |
| 539 // * count all incoming edges and backward incoming edges | |
| 540 // * number loop header blocks | |
| 541 // * create a list with all loop end blocks | |
| 542 void ComputeLinearScanOrder::count_edges(BlockBegin* cur, BlockBegin* parent) { | |
| 543 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)); | |
| 544 assert(cur->dominator() == NULL, "dominator already initialized"); | |
| 545 | |
| 546 if (is_active(cur)) { | |
| 547 TRACE_LINEAR_SCAN(3, tty->print_cr("backward branch")); | |
| 548 assert(is_visited(cur), "block must be visisted when block is active"); | |
| 549 assert(parent != NULL, "must have parent"); | |
| 550 | |
| 551 cur->set(BlockBegin::linear_scan_loop_header_flag); | |
| 552 cur->set(BlockBegin::backward_branch_target_flag); | |
| 553 | |
| 554 parent->set(BlockBegin::linear_scan_loop_end_flag); | |
|
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555 |
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556 // When a loop header is also the start of an exception handler, then the backward branch is |
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557 // an exception edge. Because such edges are usually critical edges which cannot be split, the |
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558 // loop must be excluded here from processing. |
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559 if (cur->is_set(BlockBegin::exception_entry_flag)) { |
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560 // Make sure that dominators are correct in this weird situation |
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561 _iterative_dominators = true; |
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562 return; |
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563 } |
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564 assert(parent->number_of_sux() == 1 && parent->sux_at(0) == cur, |
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565 "loop end blocks must have one successor (critical edges are split)"); |
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566 |
| 0 | 567 _loop_end_blocks.append(parent); |
| 568 return; | |
| 569 } | |
| 570 | |
| 571 // increment number of incoming forward branches | |
| 572 inc_forward_branches(cur); | |
| 573 | |
| 574 if (is_visited(cur)) { | |
| 575 TRACE_LINEAR_SCAN(3, tty->print_cr("block already visited")); | |
| 576 return; | |
| 577 } | |
| 578 | |
| 579 _num_blocks++; | |
| 580 set_visited(cur); | |
| 581 set_active(cur); | |
| 582 | |
| 583 // recursive call for all successors | |
| 584 int i; | |
| 585 for (i = cur->number_of_sux() - 1; i >= 0; i--) { | |
| 586 count_edges(cur->sux_at(i), cur); | |
| 587 } | |
| 588 for (i = cur->number_of_exception_handlers() - 1; i >= 0; i--) { | |
| 589 count_edges(cur->exception_handler_at(i), cur); | |
| 590 } | |
| 591 | |
| 592 clear_active(cur); | |
| 593 | |
| 594 // Each loop has a unique number. | |
| 595 // When multiple loops are nested, assign_loop_depth assumes that the | |
| 596 // innermost loop has the lowest number. This is guaranteed by setting | |
| 597 // the loop number after the recursive calls for the successors above | |
| 598 // have returned. | |
| 599 if (cur->is_set(BlockBegin::linear_scan_loop_header_flag)) { | |
| 600 assert(cur->loop_index() == -1, "cannot set loop-index twice"); | |
| 601 TRACE_LINEAR_SCAN(3, tty->print_cr("Block B%d is loop header of loop %d", cur->block_id(), _num_loops)); | |
| 602 | |
| 603 cur->set_loop_index(_num_loops); | |
| 8860 | 604 _loop_headers.append(cur); |
| 0 | 605 _num_loops++; |
| 606 } | |
| 607 | |
| 608 TRACE_LINEAR_SCAN(3, tty->print_cr("Finished count_edges for block B%d", cur->block_id())); | |
| 609 } | |
| 610 | |
| 611 | |
| 612 void ComputeLinearScanOrder::mark_loops() { | |
| 613 TRACE_LINEAR_SCAN(3, tty->print_cr("----- marking loops")); | |
| 614 | |
| 615 _loop_map = BitMap2D(_num_loops, _max_block_id); | |
| 616 _loop_map.clear(); | |
| 617 | |
| 618 for (int i = _loop_end_blocks.length() - 1; i >= 0; i--) { | |
| 619 BlockBegin* loop_end = _loop_end_blocks.at(i); | |
| 620 BlockBegin* loop_start = loop_end->sux_at(0); | |
| 621 int loop_idx = loop_start->loop_index(); | |
| 622 | |
| 623 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)); | |
| 624 assert(loop_end->is_set(BlockBegin::linear_scan_loop_end_flag), "loop end flag must be set"); | |
| 625 assert(loop_end->number_of_sux() == 1, "incorrect number of successors"); | |
| 626 assert(loop_start->is_set(BlockBegin::linear_scan_loop_header_flag), "loop header flag must be set"); | |
| 627 assert(loop_idx >= 0 && loop_idx < _num_loops, "loop index not set"); | |
| 628 assert(_work_list.is_empty(), "work list must be empty before processing"); | |
| 629 | |
| 630 // add the end-block of the loop to the working list | |
| 631 _work_list.push(loop_end); | |
| 632 set_block_in_loop(loop_idx, loop_end); | |
| 633 do { | |
| 634 BlockBegin* cur = _work_list.pop(); | |
| 635 | |
| 636 TRACE_LINEAR_SCAN(3, tty->print_cr(" processing B%d", cur->block_id())); | |
| 637 assert(is_block_in_loop(loop_idx, cur), "bit in loop map must be set when block is in work list"); | |
| 638 | |
| 639 // recursive processing of all predecessors ends when start block of loop is reached | |
| 640 if (cur != loop_start && !cur->is_set(BlockBegin::osr_entry_flag)) { | |
| 641 for (int j = cur->number_of_preds() - 1; j >= 0; j--) { | |
| 642 BlockBegin* pred = cur->pred_at(j); | |
| 643 | |
| 644 if (!is_block_in_loop(loop_idx, pred) /*&& !pred->is_set(BlockBeginosr_entry_flag)*/) { | |
| 645 // this predecessor has not been processed yet, so add it to work list | |
| 646 TRACE_LINEAR_SCAN(3, tty->print_cr(" pushing B%d", pred->block_id())); | |
| 647 _work_list.push(pred); | |
| 648 set_block_in_loop(loop_idx, pred); | |
| 649 } | |
| 650 } | |
| 651 } | |
| 652 } while (!_work_list.is_empty()); | |
| 653 } | |
| 654 } | |
| 655 | |
| 656 | |
| 657 // check for non-natural loops (loops where the loop header does not dominate | |
| 658 // all other loop blocks = loops with mulitple entries). | |
| 659 // such loops are ignored | |
| 660 void ComputeLinearScanOrder::clear_non_natural_loops(BlockBegin* start_block) { | |
| 661 for (int i = _num_loops - 1; i >= 0; i--) { | |
| 662 if (is_block_in_loop(i, start_block)) { | |
| 663 // loop i contains the entry block of the method | |
| 664 // -> this is not a natural loop, so ignore it | |
| 665 TRACE_LINEAR_SCAN(2, tty->print_cr("Loop %d is non-natural, so it is ignored", i)); | |
| 666 | |
| 8860 | 667 BlockBegin *loop_header = _loop_headers.at(i); |
| 668 assert(loop_header->is_set(BlockBegin::linear_scan_loop_header_flag), "Must be loop header"); | |
| 669 | |
| 670 for (int j = 0; j < loop_header->number_of_preds(); j++) { | |
| 671 BlockBegin *pred = loop_header->pred_at(j); | |
| 672 pred->clear(BlockBegin::linear_scan_loop_end_flag); | |
| 673 } | |
| 674 | |
| 675 loop_header->clear(BlockBegin::linear_scan_loop_header_flag); | |
| 676 | |
| 0 | 677 for (int block_id = _max_block_id - 1; block_id >= 0; block_id--) { |
| 678 clear_block_in_loop(i, block_id); | |
| 679 } | |
| 680 _iterative_dominators = true; | |
| 681 } | |
| 682 } | |
| 683 } | |
| 684 | |
| 685 void ComputeLinearScanOrder::assign_loop_depth(BlockBegin* start_block) { | |
| 686 TRACE_LINEAR_SCAN(3, "----- computing loop-depth and weight"); | |
| 687 init_visited(); | |
| 688 | |
| 689 assert(_work_list.is_empty(), "work list must be empty before processing"); | |
| 690 _work_list.append(start_block); | |
| 691 | |
| 692 do { | |
| 693 BlockBegin* cur = _work_list.pop(); | |
| 694 | |
| 695 if (!is_visited(cur)) { | |
| 696 set_visited(cur); | |
| 697 TRACE_LINEAR_SCAN(4, tty->print_cr("Computing loop depth for block B%d", cur->block_id())); | |
| 698 | |
| 699 // compute loop-depth and loop-index for the block | |
| 700 assert(cur->loop_depth() == 0, "cannot set loop-depth twice"); | |
| 701 int i; | |
| 702 int loop_depth = 0; | |
| 703 int min_loop_idx = -1; | |
| 704 for (i = _num_loops - 1; i >= 0; i--) { | |
| 705 if (is_block_in_loop(i, cur)) { | |
| 706 loop_depth++; | |
| 707 min_loop_idx = i; | |
| 708 } | |
| 709 } | |
| 710 cur->set_loop_depth(loop_depth); | |
| 711 cur->set_loop_index(min_loop_idx); | |
| 712 | |
| 713 // append all unvisited successors to work list | |
| 714 for (i = cur->number_of_sux() - 1; i >= 0; i--) { | |
| 715 _work_list.append(cur->sux_at(i)); | |
| 716 } | |
| 717 for (i = cur->number_of_exception_handlers() - 1; i >= 0; i--) { | |
| 718 _work_list.append(cur->exception_handler_at(i)); | |
| 719 } | |
| 720 } | |
| 721 } while (!_work_list.is_empty()); | |
| 722 } | |
| 723 | |
| 724 | |
| 725 BlockBegin* ComputeLinearScanOrder::common_dominator(BlockBegin* a, BlockBegin* b) { | |
| 726 assert(a != NULL && b != NULL, "must have input blocks"); | |
| 727 | |
| 728 _dominator_blocks.clear(); | |
| 729 while (a != NULL) { | |
| 730 _dominator_blocks.set_bit(a->block_id()); | |
| 731 assert(a->dominator() != NULL || a == _linear_scan_order->at(0), "dominator must be initialized"); | |
| 732 a = a->dominator(); | |
| 733 } | |
| 734 while (b != NULL && !_dominator_blocks.at(b->block_id())) { | |
| 735 assert(b->dominator() != NULL || b == _linear_scan_order->at(0), "dominator must be initialized"); | |
| 736 b = b->dominator(); | |
| 737 } | |
| 738 | |
| 739 assert(b != NULL, "could not find dominator"); | |
| 740 return b; | |
| 741 } | |
| 742 | |
| 743 void ComputeLinearScanOrder::compute_dominator(BlockBegin* cur, BlockBegin* parent) { | |
| 744 if (cur->dominator() == NULL) { | |
| 745 TRACE_LINEAR_SCAN(4, tty->print_cr("DOM: initializing dominator of B%d to B%d", cur->block_id(), parent->block_id())); | |
| 746 cur->set_dominator(parent); | |
| 747 | |
| 748 } else if (!(cur->is_set(BlockBegin::linear_scan_loop_header_flag) && parent->is_set(BlockBegin::linear_scan_loop_end_flag))) { | |
| 749 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())); | |
| 8860 | 750 // Does not hold for exception blocks |
| 751 assert(cur->number_of_preds() > 1 || cur->is_set(BlockBegin::exception_entry_flag), ""); | |
| 0 | 752 cur->set_dominator(common_dominator(cur->dominator(), parent)); |
| 753 } | |
| 8860 | 754 |
| 755 // Additional edge to xhandler of all our successors | |
| 756 // range check elimination needs that the state at the end of a | |
| 757 // block be valid in every block it dominates so cur must dominate | |
| 758 // the exception handlers of its successors. | |
| 759 int num_cur_xhandler = cur->number_of_exception_handlers(); | |
| 760 for (int j = 0; j < num_cur_xhandler; j++) { | |
| 761 BlockBegin* xhandler = cur->exception_handler_at(j); | |
| 762 compute_dominator(xhandler, parent); | |
| 763 } | |
| 0 | 764 } |
| 765 | |
| 766 | |
| 767 int ComputeLinearScanOrder::compute_weight(BlockBegin* cur) { | |
| 768 BlockBegin* single_sux = NULL; | |
| 769 if (cur->number_of_sux() == 1) { | |
| 770 single_sux = cur->sux_at(0); | |
| 771 } | |
| 772 | |
| 773 // limit loop-depth to 15 bit (only for security reason, it will never be so big) | |
| 774 int weight = (cur->loop_depth() & 0x7FFF) << 16; | |
| 775 | |
| 776 // general macro for short definition of weight flags | |
| 777 // the first instance of INC_WEIGHT_IF has the highest priority | |
| 778 int cur_bit = 15; | |
| 779 #define INC_WEIGHT_IF(condition) if ((condition)) { weight |= (1 << cur_bit); } cur_bit--; | |
| 780 | |
| 781 // this is necessery for the (very rare) case that two successing blocks have | |
| 782 // the same loop depth, but a different loop index (can happen for endless loops | |
| 783 // with exception handlers) | |
| 784 INC_WEIGHT_IF(!cur->is_set(BlockBegin::linear_scan_loop_header_flag)); | |
| 785 | |
| 786 // loop end blocks (blocks that end with a backward branch) are added | |
| 787 // after all other blocks of the loop. | |
| 788 INC_WEIGHT_IF(!cur->is_set(BlockBegin::linear_scan_loop_end_flag)); | |
| 789 | |
| 790 // critical edge split blocks are prefered because than they have a bigger | |
| 791 // proability to be completely empty | |
| 792 INC_WEIGHT_IF(cur->is_set(BlockBegin::critical_edge_split_flag)); | |
| 793 | |
| 794 // exceptions should not be thrown in normal control flow, so these blocks | |
| 795 // are added as late as possible | |
| 796 INC_WEIGHT_IF(cur->end()->as_Throw() == NULL && (single_sux == NULL || single_sux->end()->as_Throw() == NULL)); | |
| 797 INC_WEIGHT_IF(cur->end()->as_Return() == NULL && (single_sux == NULL || single_sux->end()->as_Return() == NULL)); | |
| 798 | |
| 799 // exceptions handlers are added as late as possible | |
| 800 INC_WEIGHT_IF(!cur->is_set(BlockBegin::exception_entry_flag)); | |
| 801 | |
| 802 // guarantee that weight is > 0 | |
| 803 weight |= 1; | |
| 804 | |
| 805 #undef INC_WEIGHT_IF | |
| 806 assert(cur_bit >= 0, "too many flags"); | |
| 807 assert(weight > 0, "weight cannot become negative"); | |
| 808 | |
| 809 return weight; | |
| 810 } | |
| 811 | |
| 812 bool ComputeLinearScanOrder::ready_for_processing(BlockBegin* cur) { | |
| 813 // Discount the edge just traveled. | |
| 814 // When the number drops to zero, all forward branches were processed | |
| 815 if (dec_forward_branches(cur) != 0) { | |
| 816 return false; | |
| 817 } | |
| 818 | |
| 819 assert(_linear_scan_order->index_of(cur) == -1, "block already processed (block can be ready only once)"); | |
| 820 assert(_work_list.index_of(cur) == -1, "block already in work-list (block can be ready only once)"); | |
| 821 return true; | |
| 822 } | |
| 823 | |
| 824 void ComputeLinearScanOrder::sort_into_work_list(BlockBegin* cur) { | |
| 825 assert(_work_list.index_of(cur) == -1, "block already in work list"); | |
| 826 | |
| 827 int cur_weight = compute_weight(cur); | |
| 828 | |
| 829 // the linear_scan_number is used to cache the weight of a block | |
| 830 cur->set_linear_scan_number(cur_weight); | |
| 831 | |
| 832 #ifndef PRODUCT | |
| 833 if (StressLinearScan) { | |
| 834 _work_list.insert_before(0, cur); | |
| 835 return; | |
| 836 } | |
| 837 #endif | |
| 838 | |
| 839 _work_list.append(NULL); // provide space for new element | |
| 840 | |
| 841 int insert_idx = _work_list.length() - 1; | |
| 842 while (insert_idx > 0 && _work_list.at(insert_idx - 1)->linear_scan_number() > cur_weight) { | |
| 843 _work_list.at_put(insert_idx, _work_list.at(insert_idx - 1)); | |
| 844 insert_idx--; | |
| 845 } | |
| 846 _work_list.at_put(insert_idx, cur); | |
| 847 | |
| 848 TRACE_LINEAR_SCAN(3, tty->print_cr("Sorted B%d into worklist. new worklist:", cur->block_id())); | |
| 849 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())); | |
| 850 | |
| 851 #ifdef ASSERT | |
| 852 for (int i = 0; i < _work_list.length(); i++) { | |
| 853 assert(_work_list.at(i)->linear_scan_number() > 0, "weight not set"); | |
| 854 assert(i == 0 || _work_list.at(i - 1)->linear_scan_number() <= _work_list.at(i)->linear_scan_number(), "incorrect order in worklist"); | |
| 855 } | |
| 856 #endif | |
| 857 } | |
| 858 | |
| 859 void ComputeLinearScanOrder::append_block(BlockBegin* cur) { | |
| 860 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())); | |
| 861 assert(_linear_scan_order->index_of(cur) == -1, "cannot add the same block twice"); | |
| 862 | |
| 863 // currently, the linear scan order and code emit order are equal. | |
| 864 // therefore the linear_scan_number and the weight of a block must also | |
| 865 // be equal. | |
| 866 cur->set_linear_scan_number(_linear_scan_order->length()); | |
| 867 _linear_scan_order->append(cur); | |
| 868 } | |
| 869 | |
| 870 void ComputeLinearScanOrder::compute_order(BlockBegin* start_block) { | |
| 871 TRACE_LINEAR_SCAN(3, "----- computing final block order"); | |
| 872 | |
| 873 // the start block is always the first block in the linear scan order | |
| 874 _linear_scan_order = new BlockList(_num_blocks); | |
| 875 append_block(start_block); | |
| 876 | |
| 877 assert(start_block->end()->as_Base() != NULL, "start block must end with Base-instruction"); | |
| 878 BlockBegin* std_entry = ((Base*)start_block->end())->std_entry(); | |
| 879 BlockBegin* osr_entry = ((Base*)start_block->end())->osr_entry(); | |
| 880 | |
| 881 BlockBegin* sux_of_osr_entry = NULL; | |
| 882 if (osr_entry != NULL) { | |
| 883 // special handling for osr entry: | |
| 884 // ignore the edge between the osr entry and its successor for processing | |
| 885 // the osr entry block is added manually below | |
| 886 assert(osr_entry->number_of_sux() == 1, "osr entry must have exactly one successor"); | |
| 887 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"); | |
| 888 | |
| 889 sux_of_osr_entry = osr_entry->sux_at(0); | |
| 890 dec_forward_branches(sux_of_osr_entry); | |
| 891 | |
| 892 compute_dominator(osr_entry, start_block); | |
| 893 _iterative_dominators = true; | |
| 894 } | |
| 895 compute_dominator(std_entry, start_block); | |
| 896 | |
| 897 // start processing with standard entry block | |
| 898 assert(_work_list.is_empty(), "list must be empty before processing"); | |
| 899 | |
| 900 if (ready_for_processing(std_entry)) { | |
| 901 sort_into_work_list(std_entry); | |
| 902 } else { | |
| 903 assert(false, "the std_entry must be ready for processing (otherwise, the method has no start block)"); | |
| 904 } | |
| 905 | |
| 906 do { | |
| 907 BlockBegin* cur = _work_list.pop(); | |
| 908 | |
| 909 if (cur == sux_of_osr_entry) { | |
| 910 // the osr entry block is ignored in normal processing, it is never added to the | |
| 911 // work list. Instead, it is added as late as possible manually here. | |
| 912 append_block(osr_entry); | |
| 913 compute_dominator(cur, osr_entry); | |
| 914 } | |
| 915 append_block(cur); | |
| 916 | |
| 917 int i; | |
| 918 int num_sux = cur->number_of_sux(); | |
| 919 // changed loop order to get "intuitive" order of if- and else-blocks | |
| 920 for (i = 0; i < num_sux; i++) { | |
| 921 BlockBegin* sux = cur->sux_at(i); | |
| 922 compute_dominator(sux, cur); | |
| 923 if (ready_for_processing(sux)) { | |
| 924 sort_into_work_list(sux); | |
| 925 } | |
| 926 } | |
| 927 num_sux = cur->number_of_exception_handlers(); | |
| 928 for (i = 0; i < num_sux; i++) { | |
| 929 BlockBegin* sux = cur->exception_handler_at(i); | |
| 930 if (ready_for_processing(sux)) { | |
| 931 sort_into_work_list(sux); | |
| 932 } | |
| 933 } | |
| 934 } while (_work_list.length() > 0); | |
| 935 } | |
| 936 | |
| 937 | |
| 938 bool ComputeLinearScanOrder::compute_dominators_iter() { | |
| 939 bool changed = false; | |
| 940 int num_blocks = _linear_scan_order->length(); | |
| 941 | |
| 942 assert(_linear_scan_order->at(0)->dominator() == NULL, "must not have dominator"); | |
| 943 assert(_linear_scan_order->at(0)->number_of_preds() == 0, "must not have predecessors"); | |
| 944 for (int i = 1; i < num_blocks; i++) { | |
| 945 BlockBegin* block = _linear_scan_order->at(i); | |
| 946 | |
| 947 BlockBegin* dominator = block->pred_at(0); | |
| 948 int num_preds = block->number_of_preds(); | |
| 8860 | 949 |
| 950 TRACE_LINEAR_SCAN(4, tty->print_cr("DOM: Processing B%d", block->block_id())); | |
| 951 | |
| 952 for (int j = 0; j < num_preds; j++) { | |
| 953 | |
| 954 BlockBegin *pred = block->pred_at(j); | |
| 955 TRACE_LINEAR_SCAN(4, tty->print_cr(" DOM: Subrocessing B%d", pred->block_id())); | |
| 956 | |
| 957 if (block->is_set(BlockBegin::exception_entry_flag)) { | |
| 958 dominator = common_dominator(dominator, pred); | |
| 959 int num_pred_preds = pred->number_of_preds(); | |
| 960 for (int k = 0; k < num_pred_preds; k++) { | |
| 961 dominator = common_dominator(dominator, pred->pred_at(k)); | |
| 962 } | |
| 963 } else { | |
| 964 dominator = common_dominator(dominator, pred); | |
| 965 } | |
| 0 | 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"); | |
| 8860 | 992 |
| 993 // Add Blocks to dominates-Array | |
| 994 int num_blocks = _linear_scan_order->length(); | |
| 995 for (int i = 0; i < num_blocks; i++) { | |
| 996 BlockBegin* block = _linear_scan_order->at(i); | |
| 997 | |
| 998 BlockBegin *dom = block->dominator(); | |
| 999 if (dom) { | |
| 1000 assert(dom->dominator_depth() != -1, "Dominator must have been visited before"); | |
| 1001 dom->dominates()->append(block); | |
| 1002 block->set_dominator_depth(dom->dominator_depth() + 1); | |
| 1003 } else { | |
| 1004 block->set_dominator_depth(0); | |
| 1005 } | |
| 1006 } | |
| 0 | 1007 } |
| 1008 | |
| 1009 | |
| 1010 #ifndef PRODUCT | |
| 1011 void ComputeLinearScanOrder::print_blocks() { | |
| 1012 if (TraceLinearScanLevel >= 2) { | |
| 1013 tty->print_cr("----- loop information:"); | |
| 1014 for (int block_idx = 0; block_idx < _linear_scan_order->length(); block_idx++) { | |
| 1015 BlockBegin* cur = _linear_scan_order->at(block_idx); | |
| 1016 | |
| 1017 tty->print("%4d: B%2d: ", cur->linear_scan_number(), cur->block_id()); | |
| 1018 for (int loop_idx = 0; loop_idx < _num_loops; loop_idx++) { | |
| 1019 tty->print ("%d ", is_block_in_loop(loop_idx, cur)); | |
| 1020 } | |
| 1021 tty->print_cr(" -> loop_index: %2d, loop_depth: %2d", cur->loop_index(), cur->loop_depth()); | |
| 1022 } | |
| 1023 } | |
| 1024 | |
| 1025 if (TraceLinearScanLevel >= 1) { | |
| 1026 tty->print_cr("----- linear-scan block order:"); | |
| 1027 for (int block_idx = 0; block_idx < _linear_scan_order->length(); block_idx++) { | |
| 1028 BlockBegin* cur = _linear_scan_order->at(block_idx); | |
| 1029 tty->print("%4d: B%2d loop: %2d depth: %2d", cur->linear_scan_number(), cur->block_id(), cur->loop_index(), cur->loop_depth()); | |
| 1030 | |
| 1031 tty->print(cur->is_set(BlockBegin::exception_entry_flag) ? " ex" : " "); | |
| 1032 tty->print(cur->is_set(BlockBegin::critical_edge_split_flag) ? " ce" : " "); | |
| 1033 tty->print(cur->is_set(BlockBegin::linear_scan_loop_header_flag) ? " lh" : " "); | |
| 1034 tty->print(cur->is_set(BlockBegin::linear_scan_loop_end_flag) ? " le" : " "); | |
| 1035 | |
| 1036 if (cur->dominator() != NULL) { | |
| 1037 tty->print(" dom: B%d ", cur->dominator()->block_id()); | |
| 1038 } else { | |
| 1039 tty->print(" dom: NULL "); | |
| 1040 } | |
| 1041 | |
| 1042 if (cur->number_of_preds() > 0) { | |
| 1043 tty->print(" preds: "); | |
| 1044 for (int j = 0; j < cur->number_of_preds(); j++) { | |
| 1045 BlockBegin* pred = cur->pred_at(j); | |
| 1046 tty->print("B%d ", pred->block_id()); | |
| 1047 } | |
| 1048 } | |
| 1049 if (cur->number_of_sux() > 0) { | |
| 1050 tty->print(" sux: "); | |
| 1051 for (int j = 0; j < cur->number_of_sux(); j++) { | |
| 1052 BlockBegin* sux = cur->sux_at(j); | |
| 1053 tty->print("B%d ", sux->block_id()); | |
| 1054 } | |
| 1055 } | |
| 1056 if (cur->number_of_exception_handlers() > 0) { | |
| 1057 tty->print(" ex: "); | |
| 1058 for (int j = 0; j < cur->number_of_exception_handlers(); j++) { | |
| 1059 BlockBegin* ex = cur->exception_handler_at(j); | |
| 1060 tty->print("B%d ", ex->block_id()); | |
| 1061 } | |
| 1062 } | |
| 1063 tty->cr(); | |
| 1064 } | |
| 1065 } | |
| 1066 } | |
| 1067 #endif | |
| 1068 | |
| 1069 #ifdef ASSERT | |
| 1070 void ComputeLinearScanOrder::verify() { | |
| 1071 assert(_linear_scan_order->length() == _num_blocks, "wrong number of blocks in list"); | |
| 1072 | |
| 1073 if (StressLinearScan) { | |
| 1074 // blocks are scrambled when StressLinearScan is used | |
| 1075 return; | |
| 1076 } | |
| 1077 | |
| 1078 // check that all successors of a block have a higher linear-scan-number | |
| 1079 // and that all predecessors of a block have a lower linear-scan-number | |
| 1080 // (only backward branches of loops are ignored) | |
| 1081 int i; | |
| 1082 for (i = 0; i < _linear_scan_order->length(); i++) { | |
| 1083 BlockBegin* cur = _linear_scan_order->at(i); | |
| 1084 | |
| 1085 assert(cur->linear_scan_number() == i, "incorrect linear_scan_number"); | |
| 1086 assert(cur->linear_scan_number() >= 0 && cur->linear_scan_number() == _linear_scan_order->index_of(cur), "incorrect linear_scan_number"); | |
| 1087 | |
| 1088 int j; | |
| 1089 for (j = cur->number_of_sux() - 1; j >= 0; j--) { | |
| 1090 BlockBegin* sux = cur->sux_at(j); | |
| 1091 | |
| 1092 assert(sux->linear_scan_number() >= 0 && sux->linear_scan_number() == _linear_scan_order->index_of(sux), "incorrect linear_scan_number"); | |
| 8860 | 1093 if (!sux->is_set(BlockBegin::backward_branch_target_flag)) { |
| 0 | 1094 assert(cur->linear_scan_number() < sux->linear_scan_number(), "invalid order"); |
| 1095 } | |
| 1096 if (cur->loop_depth() == sux->loop_depth()) { | |
| 1097 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"); | |
| 1098 } | |
| 1099 } | |
| 1100 | |
| 1101 for (j = cur->number_of_preds() - 1; j >= 0; j--) { | |
| 1102 BlockBegin* pred = cur->pred_at(j); | |
| 1103 | |
| 1104 assert(pred->linear_scan_number() >= 0 && pred->linear_scan_number() == _linear_scan_order->index_of(pred), "incorrect linear_scan_number"); | |
| 8860 | 1105 if (!cur->is_set(BlockBegin::backward_branch_target_flag)) { |
| 0 | 1106 assert(cur->linear_scan_number() > pred->linear_scan_number(), "invalid order"); |
| 1107 } | |
| 1108 if (cur->loop_depth() == pred->loop_depth()) { | |
| 1109 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"); | |
| 1110 } | |
| 1111 | |
| 1112 assert(cur->dominator()->linear_scan_number() <= cur->pred_at(j)->linear_scan_number(), "dominator must be before predecessors"); | |
| 1113 } | |
| 1114 | |
| 1115 // check dominator | |
| 1116 if (i == 0) { | |
| 1117 assert(cur->dominator() == NULL, "first block has no dominator"); | |
| 1118 } else { | |
| 1119 assert(cur->dominator() != NULL, "all but first block must have dominator"); | |
| 1120 } | |
| 8860 | 1121 // Assertion does not hold for exception handlers |
| 1122 assert(cur->number_of_preds() != 1 || cur->dominator() == cur->pred_at(0) || cur->is_set(BlockBegin::exception_entry_flag), "Single predecessor must also be dominator"); | |
| 0 | 1123 } |
| 1124 | |
| 1125 // check that all loops are continuous | |
| 1126 for (int loop_idx = 0; loop_idx < _num_loops; loop_idx++) { | |
| 1127 int block_idx = 0; | |
| 1128 assert(!is_block_in_loop(loop_idx, _linear_scan_order->at(block_idx)), "the first block must not be present in any loop"); | |
| 1129 | |
| 1130 // skip blocks before the loop | |
| 1131 while (block_idx < _num_blocks && !is_block_in_loop(loop_idx, _linear_scan_order->at(block_idx))) { | |
| 1132 block_idx++; | |
| 1133 } | |
| 1134 // skip blocks of loop | |
| 1135 while (block_idx < _num_blocks && is_block_in_loop(loop_idx, _linear_scan_order->at(block_idx))) { | |
| 1136 block_idx++; | |
| 1137 } | |
| 1138 // after the first non-loop block, there must not be another loop-block | |
| 1139 while (block_idx < _num_blocks) { | |
| 1140 assert(!is_block_in_loop(loop_idx, _linear_scan_order->at(block_idx)), "loop not continuous in linear-scan order"); | |
| 1141 block_idx++; | |
| 1142 } | |
| 1143 } | |
| 1144 } | |
| 1145 #endif | |
| 1146 | |
| 1147 | |
| 1148 void IR::compute_code() { | |
| 1149 assert(is_valid(), "IR must be valid"); | |
| 1150 | |
| 1783 | 1151 ComputeLinearScanOrder compute_order(compilation(), start()); |
| 0 | 1152 _num_loops = compute_order.num_loops(); |
| 1153 _code = compute_order.linear_scan_order(); | |
| 1154 } | |
| 1155 | |
| 1156 | |
| 1157 void IR::compute_use_counts() { | |
| 1158 // make sure all values coming out of this block get evaluated. | |
| 1159 int num_blocks = _code->length(); | |
| 1160 for (int i = 0; i < num_blocks; i++) { | |
| 1161 _code->at(i)->end()->state()->pin_stack_for_linear_scan(); | |
| 1162 } | |
| 1163 | |
| 1164 // compute use counts | |
| 1165 UseCountComputer::compute(_code); | |
| 1166 } | |
| 1167 | |
| 1168 | |
| 1169 void IR::iterate_preorder(BlockClosure* closure) { | |
| 1170 assert(is_valid(), "IR must be valid"); | |
| 1171 start()->iterate_preorder(closure); | |
| 1172 } | |
| 1173 | |
| 1174 | |
| 1175 void IR::iterate_postorder(BlockClosure* closure) { | |
| 1176 assert(is_valid(), "IR must be valid"); | |
| 1177 start()->iterate_postorder(closure); | |
| 1178 } | |
| 1179 | |
| 1180 void IR::iterate_linear_scan_order(BlockClosure* closure) { | |
| 1181 linear_scan_order()->iterate_forward(closure); | |
| 1182 } | |
| 1183 | |
| 1184 | |
| 1185 #ifndef PRODUCT | |
| 1186 class BlockPrinter: public BlockClosure { | |
| 1187 private: | |
| 1188 InstructionPrinter* _ip; | |
| 1189 bool _cfg_only; | |
| 1190 bool _live_only; | |
| 1191 | |
| 1192 public: | |
| 1193 BlockPrinter(InstructionPrinter* ip, bool cfg_only, bool live_only = false) { | |
| 1194 _ip = ip; | |
| 1195 _cfg_only = cfg_only; | |
| 1196 _live_only = live_only; | |
| 1197 } | |
| 1198 | |
| 1199 virtual void block_do(BlockBegin* block) { | |
| 1200 if (_cfg_only) { | |
| 1201 _ip->print_instr(block); tty->cr(); | |
| 1202 } else { | |
| 1203 block->print_block(*_ip, _live_only); | |
| 1204 } | |
| 1205 } | |
| 1206 }; | |
| 1207 | |
| 1208 | |
| 1209 void IR::print(BlockBegin* start, bool cfg_only, bool live_only) { | |
| 1210 ttyLocker ttyl; | |
| 1211 InstructionPrinter ip(!cfg_only); | |
| 1212 BlockPrinter bp(&ip, cfg_only, live_only); | |
| 1213 start->iterate_preorder(&bp); | |
| 1214 tty->cr(); | |
| 1215 } | |
| 1216 | |
| 1217 void IR::print(bool cfg_only, bool live_only) { | |
| 1218 if (is_valid()) { | |
| 1219 print(start(), cfg_only, live_only); | |
| 1220 } else { | |
| 1221 tty->print_cr("invalid IR"); | |
| 1222 } | |
| 1223 } | |
| 1224 | |
| 1225 | |
| 1226 define_array(BlockListArray, BlockList*) | |
| 1227 define_stack(BlockListList, BlockListArray) | |
| 1228 | |
| 1229 class PredecessorValidator : public BlockClosure { | |
| 1230 private: | |
| 1231 BlockListList* _predecessors; | |
| 1232 BlockList* _blocks; | |
| 1233 | |
| 1234 static int cmp(BlockBegin** a, BlockBegin** b) { | |
| 1235 return (*a)->block_id() - (*b)->block_id(); | |
| 1236 } | |
| 1237 | |
| 1238 public: | |
| 1239 PredecessorValidator(IR* hir) { | |
| 1240 ResourceMark rm; | |
| 1241 _predecessors = new BlockListList(BlockBegin::number_of_blocks(), NULL); | |
| 1242 _blocks = new BlockList(); | |
| 1243 | |
| 1244 int i; | |
| 1245 hir->start()->iterate_preorder(this); | |
| 1246 if (hir->code() != NULL) { | |
| 1247 assert(hir->code()->length() == _blocks->length(), "must match"); | |
| 1248 for (i = 0; i < _blocks->length(); i++) { | |
| 1249 assert(hir->code()->contains(_blocks->at(i)), "should be in both lists"); | |
| 1250 } | |
| 1251 } | |
| 1252 | |
| 1253 for (i = 0; i < _blocks->length(); i++) { | |
| 1254 BlockBegin* block = _blocks->at(i); | |
| 1255 BlockList* preds = _predecessors->at(block->block_id()); | |
| 1256 if (preds == NULL) { | |
| 1257 assert(block->number_of_preds() == 0, "should be the same"); | |
| 1258 continue; | |
| 1259 } | |
| 1260 | |
| 1261 // clone the pred list so we can mutate it | |
| 1262 BlockList* pred_copy = new BlockList(); | |
| 1263 int j; | |
| 1264 for (j = 0; j < block->number_of_preds(); j++) { | |
| 1265 pred_copy->append(block->pred_at(j)); | |
| 1266 } | |
| 1267 // sort them in the same order | |
| 1268 preds->sort(cmp); | |
| 1269 pred_copy->sort(cmp); | |
| 1270 int length = MIN2(preds->length(), block->number_of_preds()); | |
| 1271 for (j = 0; j < block->number_of_preds(); j++) { | |
| 1272 assert(preds->at(j) == pred_copy->at(j), "must match"); | |
| 1273 } | |
| 1274 | |
| 1275 assert(preds->length() == block->number_of_preds(), "should be the same"); | |
| 1276 } | |
| 1277 } | |
| 1278 | |
| 1279 virtual void block_do(BlockBegin* block) { | |
| 1280 _blocks->append(block); | |
| 1281 BlockEnd* be = block->end(); | |
| 1282 int n = be->number_of_sux(); | |
| 1283 int i; | |
| 1284 for (i = 0; i < n; i++) { | |
| 1285 BlockBegin* sux = be->sux_at(i); | |
| 1286 assert(!sux->is_set(BlockBegin::exception_entry_flag), "must not be xhandler"); | |
| 1287 | |
| 1288 BlockList* preds = _predecessors->at_grow(sux->block_id(), NULL); | |
| 1289 if (preds == NULL) { | |
| 1290 preds = new BlockList(); | |
| 1291 _predecessors->at_put(sux->block_id(), preds); | |
| 1292 } | |
| 1293 preds->append(block); | |
| 1294 } | |
| 1295 | |
| 1296 n = block->number_of_exception_handlers(); | |
| 1297 for (i = 0; i < n; i++) { | |
| 1298 BlockBegin* sux = block->exception_handler_at(i); | |
| 1299 assert(sux->is_set(BlockBegin::exception_entry_flag), "must be xhandler"); | |
| 1300 | |
| 1301 BlockList* preds = _predecessors->at_grow(sux->block_id(), NULL); | |
| 1302 if (preds == NULL) { | |
| 1303 preds = new BlockList(); | |
| 1304 _predecessors->at_put(sux->block_id(), preds); | |
| 1305 } | |
| 1306 preds->append(block); | |
| 1307 } | |
| 1308 } | |
| 1309 }; | |
| 1310 | |
| 8860 | 1311 class VerifyBlockBeginField : public BlockClosure { |
| 1312 | |
| 1313 public: | |
| 1314 | |
| 1315 virtual void block_do(BlockBegin *block) { | |
| 1316 for ( Instruction *cur = block; cur != NULL; cur = cur->next()) { | |
| 1317 assert(cur->block() == block, "Block begin is not correct"); | |
| 1318 } | |
| 1319 } | |
| 1320 }; | |
| 1321 | |
| 0 | 1322 void IR::verify() { |
| 1323 #ifdef ASSERT | |
| 1324 PredecessorValidator pv(this); | |
| 8860 | 1325 VerifyBlockBeginField verifier; |
| 1326 this->iterate_postorder(&verifier); | |
| 0 | 1327 #endif |
| 1328 } | |
| 1329 | |
| 1330 #endif // PRODUCT | |
| 1331 | |
| 1584 | 1332 void SubstitutionResolver::visit(Value* v) { |
| 0 | 1333 Value v0 = *v; |
| 1334 if (v0) { | |
| 1335 Value vs = v0->subst(); | |
| 1336 if (vs != v0) { | |
| 1337 *v = v0->subst(); | |
| 1338 } | |
| 1339 } | |
| 1340 } | |
| 1341 | |
| 1342 #ifdef ASSERT | |
| 1584 | 1343 class SubstitutionChecker: public ValueVisitor { |
| 1344 void visit(Value* v) { | |
| 1345 Value v0 = *v; | |
| 1346 if (v0) { | |
| 1347 Value vs = v0->subst(); | |
| 1348 assert(vs == v0, "missed substitution"); | |
| 1349 } | |
| 0 | 1350 } |
| 1584 | 1351 }; |
| 0 | 1352 #endif |
| 1353 | |
| 1354 | |
| 1355 void SubstitutionResolver::block_do(BlockBegin* block) { | |
| 1356 Instruction* last = NULL; | |
| 1357 for (Instruction* n = block; n != NULL;) { | |
| 1584 | 1358 n->values_do(this); |
| 0 | 1359 // need to remove this instruction from the instruction stream |
| 1360 if (n->subst() != n) { | |
| 1361 assert(last != NULL, "must have last"); | |
| 1819 | 1362 last->set_next(n->next()); |
| 0 | 1363 } else { |
| 1364 last = n; | |
| 1365 } | |
| 1366 n = last->next(); | |
| 1367 } | |
| 1368 | |
| 1369 #ifdef ASSERT | |
| 1584 | 1370 SubstitutionChecker check_substitute; |
| 1371 if (block->state()) block->state()->values_do(&check_substitute); | |
| 1372 block->block_values_do(&check_substitute); | |
| 1373 if (block->end() && block->end()->state()) block->end()->state()->values_do(&check_substitute); | |
| 0 | 1374 #endif |
| 1375 } |