src/share/vm/c1/c1_IR.cpp

Fri, 04 Jun 2010 11:18:04 -0700

author
iveresov
date
Fri, 04 Jun 2010 11:18:04 -0700
changeset 1939
b812ff5abc73
parent 1934
e9ff18c4ace7
child 2138
d5d065957597
permissions
-rw-r--r--

6958292: C1: Enable parallel compilation
Summary: Enable parallel compilation in C1
Reviewed-by: never, kvn

duke@435 1 /*
trims@1907 2 * Copyright (c) 1999, 2010, Oracle and/or its affiliates. All rights reserved.
duke@435 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@435 4 *
duke@435 5 * This code is free software; you can redistribute it and/or modify it
duke@435 6 * under the terms of the GNU General Public License version 2 only, as
duke@435 7 * published by the Free Software Foundation.
duke@435 8 *
duke@435 9 * This code is distributed in the hope that it will be useful, but WITHOUT
duke@435 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@435 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
duke@435 12 * version 2 for more details (a copy is included in the LICENSE file that
duke@435 13 * accompanied this code).
duke@435 14 *
duke@435 15 * You should have received a copy of the GNU General Public License version
duke@435 16 * 2 along with this work; if not, write to the Free Software Foundation,
duke@435 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@435 18 *
trims@1907 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
trims@1907 20 * or visit www.oracle.com if you need additional information or have any
trims@1907 21 * questions.
duke@435 22 *
duke@435 23 */
duke@435 24
duke@435 25 # include "incls/_precompiled.incl"
duke@435 26 # include "incls/_c1_IR.cpp.incl"
duke@435 27
duke@435 28
duke@435 29 // Implementation of XHandlers
duke@435 30 //
duke@435 31 // Note: This code could eventually go away if we are
duke@435 32 // just using the ciExceptionHandlerStream.
duke@435 33
duke@435 34 XHandlers::XHandlers(ciMethod* method) : _list(method->exception_table_length()) {
duke@435 35 ciExceptionHandlerStream s(method);
duke@435 36 while (!s.is_done()) {
duke@435 37 _list.append(new XHandler(s.handler()));
duke@435 38 s.next();
duke@435 39 }
duke@435 40 assert(s.count() == method->exception_table_length(), "exception table lengths inconsistent");
duke@435 41 }
duke@435 42
duke@435 43 // deep copy of all XHandler contained in list
duke@435 44 XHandlers::XHandlers(XHandlers* other) :
duke@435 45 _list(other->length())
duke@435 46 {
duke@435 47 for (int i = 0; i < other->length(); i++) {
duke@435 48 _list.append(new XHandler(other->handler_at(i)));
duke@435 49 }
duke@435 50 }
duke@435 51
duke@435 52 // Returns whether a particular exception type can be caught. Also
duke@435 53 // returns true if klass is unloaded or any exception handler
duke@435 54 // classes are unloaded. type_is_exact indicates whether the throw
duke@435 55 // is known to be exactly that class or it might throw a subtype.
duke@435 56 bool XHandlers::could_catch(ciInstanceKlass* klass, bool type_is_exact) const {
duke@435 57 // the type is unknown so be conservative
duke@435 58 if (!klass->is_loaded()) {
duke@435 59 return true;
duke@435 60 }
duke@435 61
duke@435 62 for (int i = 0; i < length(); i++) {
duke@435 63 XHandler* handler = handler_at(i);
duke@435 64 if (handler->is_catch_all()) {
duke@435 65 // catch of ANY
duke@435 66 return true;
duke@435 67 }
duke@435 68 ciInstanceKlass* handler_klass = handler->catch_klass();
duke@435 69 // if it's unknown it might be catchable
duke@435 70 if (!handler_klass->is_loaded()) {
duke@435 71 return true;
duke@435 72 }
duke@435 73 // if the throw type is definitely a subtype of the catch type
duke@435 74 // then it can be caught.
duke@435 75 if (klass->is_subtype_of(handler_klass)) {
duke@435 76 return true;
duke@435 77 }
duke@435 78 if (!type_is_exact) {
duke@435 79 // If the type isn't exactly known then it can also be caught by
duke@435 80 // catch statements where the inexact type is a subtype of the
duke@435 81 // catch type.
duke@435 82 // given: foo extends bar extends Exception
duke@435 83 // throw bar can be caught by catch foo, catch bar, and catch
duke@435 84 // Exception, however it can't be caught by any handlers without
duke@435 85 // bar in its type hierarchy.
duke@435 86 if (handler_klass->is_subtype_of(klass)) {
duke@435 87 return true;
duke@435 88 }
duke@435 89 }
duke@435 90 }
duke@435 91
duke@435 92 return false;
duke@435 93 }
duke@435 94
duke@435 95
duke@435 96 bool XHandlers::equals(XHandlers* others) const {
duke@435 97 if (others == NULL) return false;
duke@435 98 if (length() != others->length()) return false;
duke@435 99
duke@435 100 for (int i = 0; i < length(); i++) {
duke@435 101 if (!handler_at(i)->equals(others->handler_at(i))) return false;
duke@435 102 }
duke@435 103 return true;
duke@435 104 }
duke@435 105
duke@435 106 bool XHandler::equals(XHandler* other) const {
duke@435 107 assert(entry_pco() != -1 && other->entry_pco() != -1, "must have entry_pco");
duke@435 108
duke@435 109 if (entry_pco() != other->entry_pco()) return false;
duke@435 110 if (scope_count() != other->scope_count()) return false;
duke@435 111 if (_desc != other->_desc) return false;
duke@435 112
duke@435 113 assert(entry_block() == other->entry_block(), "entry_block must be equal when entry_pco is equal");
duke@435 114 return true;
duke@435 115 }
duke@435 116
duke@435 117
duke@435 118 // Implementation of IRScope
duke@435 119
duke@435 120 BlockBegin* IRScope::header_block(BlockBegin* entry, BlockBegin::Flag f, ValueStack* state) {
duke@435 121 if (entry == NULL) return NULL;
duke@435 122 assert(entry->is_set(f), "entry/flag mismatch");
duke@435 123 // create header block
duke@435 124 BlockBegin* h = new BlockBegin(entry->bci());
duke@435 125 BlockEnd* g = new Goto(entry, false);
duke@435 126 h->set_next(g, entry->bci());
duke@435 127 h->set_end(g);
duke@435 128 h->set(f);
duke@435 129 // setup header block end state
duke@435 130 ValueStack* s = state->copy(); // can use copy since stack is empty (=> no phis)
duke@435 131 assert(s->stack_is_empty(), "must have empty stack at entry point");
duke@435 132 g->set_state(s);
duke@435 133 return h;
duke@435 134 }
duke@435 135
duke@435 136
duke@435 137 BlockBegin* IRScope::build_graph(Compilation* compilation, int osr_bci) {
duke@435 138 GraphBuilder gm(compilation, this);
duke@435 139 NOT_PRODUCT(if (PrintValueNumbering && Verbose) gm.print_stats());
duke@435 140 if (compilation->bailed_out()) return NULL;
duke@435 141 return gm.start();
duke@435 142 }
duke@435 143
duke@435 144
duke@435 145 IRScope::IRScope(Compilation* compilation, IRScope* caller, int caller_bci, ciMethod* method, int osr_bci, bool create_graph)
duke@435 146 : _callees(2)
duke@435 147 , _compilation(compilation)
duke@435 148 , _lock_stack_size(-1)
duke@435 149 , _requires_phi_function(method->max_locals())
duke@435 150 {
duke@435 151 _caller = caller;
duke@435 152 _caller_bci = caller == NULL ? -1 : caller_bci;
duke@435 153 _caller_state = NULL; // Must be set later if needed
duke@435 154 _level = caller == NULL ? 0 : caller->level() + 1;
duke@435 155 _method = method;
duke@435 156 _xhandlers = new XHandlers(method);
duke@435 157 _number_of_locks = 0;
duke@435 158 _monitor_pairing_ok = method->has_balanced_monitors();
duke@435 159 _start = NULL;
duke@435 160
duke@435 161 if (osr_bci == -1) {
duke@435 162 _requires_phi_function.clear();
duke@435 163 } else {
duke@435 164 // selective creation of phi functions is not possibel in osr-methods
duke@435 165 _requires_phi_function.set_range(0, method->max_locals());
duke@435 166 }
duke@435 167
duke@435 168 assert(method->holder()->is_loaded() , "method holder must be loaded");
duke@435 169
duke@435 170 // build graph if monitor pairing is ok
duke@435 171 if (create_graph && monitor_pairing_ok()) _start = build_graph(compilation, osr_bci);
duke@435 172 }
duke@435 173
duke@435 174
duke@435 175 int IRScope::max_stack() const {
duke@435 176 int my_max = method()->max_stack();
duke@435 177 int callee_max = 0;
duke@435 178 for (int i = 0; i < number_of_callees(); i++) {
duke@435 179 callee_max = MAX2(callee_max, callee_no(i)->max_stack());
duke@435 180 }
duke@435 181 return my_max + callee_max;
duke@435 182 }
duke@435 183
duke@435 184
duke@435 185 void IRScope::compute_lock_stack_size() {
duke@435 186 if (!InlineMethodsWithExceptionHandlers) {
duke@435 187 _lock_stack_size = 0;
duke@435 188 return;
duke@435 189 }
duke@435 190
duke@435 191 // Figure out whether we have to preserve expression stack elements
duke@435 192 // for parent scopes, and if so, how many
duke@435 193 IRScope* cur_scope = this;
duke@435 194 while (cur_scope != NULL && !cur_scope->xhandlers()->has_handlers()) {
duke@435 195 cur_scope = cur_scope->caller();
duke@435 196 }
duke@435 197 _lock_stack_size = (cur_scope == NULL ? 0 :
duke@435 198 (cur_scope->caller_state() == NULL ? 0 :
duke@435 199 cur_scope->caller_state()->stack_size()));
duke@435 200 }
duke@435 201
duke@435 202 int IRScope::top_scope_bci() const {
duke@435 203 assert(!is_top_scope(), "no correct answer for top scope possible");
duke@435 204 const IRScope* scope = this;
duke@435 205 while (!scope->caller()->is_top_scope()) {
duke@435 206 scope = scope->caller();
duke@435 207 }
duke@435 208 return scope->caller_bci();
duke@435 209 }
duke@435 210
cfang@1335 211 bool IRScopeDebugInfo::should_reexecute() {
cfang@1335 212 ciMethod* cur_method = scope()->method();
cfang@1335 213 int cur_bci = bci();
cfang@1335 214 if (cur_method != NULL && cur_bci != SynchronizationEntryBCI) {
cfang@1335 215 Bytecodes::Code code = cur_method->java_code_at_bci(cur_bci);
cfang@1335 216 return Interpreter::bytecode_should_reexecute(code);
cfang@1335 217 } else
cfang@1335 218 return false;
cfang@1335 219 }
duke@435 220
duke@435 221
duke@435 222 // Implementation of CodeEmitInfo
duke@435 223
duke@435 224 // Stack must be NON-null
duke@435 225 CodeEmitInfo::CodeEmitInfo(int bci, ValueStack* stack, XHandlers* exception_handlers)
duke@435 226 : _scope(stack->scope())
duke@435 227 , _bci(bci)
duke@435 228 , _scope_debug_info(NULL)
duke@435 229 , _oop_map(NULL)
duke@435 230 , _stack(stack)
duke@435 231 , _exception_handlers(exception_handlers)
duke@435 232 , _next(NULL)
twisti@1919 233 , _id(-1)
twisti@1919 234 , _is_method_handle_invoke(false) {
duke@435 235 assert(_stack != NULL, "must be non null");
duke@435 236 assert(_bci == SynchronizationEntryBCI || Bytecodes::is_defined(scope()->method()->java_code_at_bci(_bci)), "make sure bci points at a real bytecode");
duke@435 237 }
duke@435 238
duke@435 239
duke@435 240 CodeEmitInfo::CodeEmitInfo(CodeEmitInfo* info, bool lock_stack_only)
duke@435 241 : _scope(info->_scope)
duke@435 242 , _exception_handlers(NULL)
duke@435 243 , _bci(info->_bci)
duke@435 244 , _scope_debug_info(NULL)
twisti@1919 245 , _oop_map(NULL)
twisti@1919 246 , _is_method_handle_invoke(info->_is_method_handle_invoke) {
duke@435 247 if (lock_stack_only) {
duke@435 248 if (info->_stack != NULL) {
duke@435 249 _stack = info->_stack->copy_locks();
duke@435 250 } else {
duke@435 251 _stack = NULL;
duke@435 252 }
duke@435 253 } else {
duke@435 254 _stack = info->_stack;
duke@435 255 }
duke@435 256
duke@435 257 // deep copy of exception handlers
duke@435 258 if (info->_exception_handlers != NULL) {
duke@435 259 _exception_handlers = new XHandlers(info->_exception_handlers);
duke@435 260 }
duke@435 261 }
duke@435 262
duke@435 263
twisti@1919 264 void CodeEmitInfo::record_debug_info(DebugInformationRecorder* recorder, int pc_offset) {
duke@435 265 // record the safepoint before recording the debug info for enclosing scopes
duke@435 266 recorder->add_safepoint(pc_offset, _oop_map->deep_copy());
twisti@1919 267 _scope_debug_info->record_debug_info(recorder, pc_offset, true/*topmost*/, _is_method_handle_invoke);
duke@435 268 recorder->end_safepoint(pc_offset);
duke@435 269 }
duke@435 270
duke@435 271
duke@435 272 void CodeEmitInfo::add_register_oop(LIR_Opr opr) {
duke@435 273 assert(_oop_map != NULL, "oop map must already exist");
duke@435 274 assert(opr->is_single_cpu(), "should not call otherwise");
duke@435 275
duke@435 276 int frame_size = frame_map()->framesize();
duke@435 277 int arg_count = frame_map()->oop_map_arg_count();
duke@435 278 VMReg name = frame_map()->regname(opr);
duke@435 279 _oop_map->set_oop(name);
duke@435 280 }
duke@435 281
duke@435 282
duke@435 283
duke@435 284
duke@435 285 // Implementation of IR
duke@435 286
duke@435 287 IR::IR(Compilation* compilation, ciMethod* method, int osr_bci) :
duke@435 288 _locals_size(in_WordSize(-1))
duke@435 289 , _num_loops(0) {
duke@435 290 // setup IR fields
duke@435 291 _compilation = compilation;
duke@435 292 _top_scope = new IRScope(compilation, NULL, -1, method, osr_bci, true);
duke@435 293 _code = NULL;
duke@435 294 }
duke@435 295
duke@435 296
duke@435 297 void IR::optimize() {
duke@435 298 Optimizer opt(this);
duke@435 299 if (DoCEE) {
duke@435 300 opt.eliminate_conditional_expressions();
duke@435 301 #ifndef PRODUCT
duke@435 302 if (PrintCFG || PrintCFG1) { tty->print_cr("CFG after CEE"); print(true); }
duke@435 303 if (PrintIR || PrintIR1 ) { tty->print_cr("IR after CEE"); print(false); }
duke@435 304 #endif
duke@435 305 }
duke@435 306 if (EliminateBlocks) {
duke@435 307 opt.eliminate_blocks();
duke@435 308 #ifndef PRODUCT
duke@435 309 if (PrintCFG || PrintCFG1) { tty->print_cr("CFG after block elimination"); print(true); }
duke@435 310 if (PrintIR || PrintIR1 ) { tty->print_cr("IR after block elimination"); print(false); }
duke@435 311 #endif
duke@435 312 }
duke@435 313 if (EliminateNullChecks) {
duke@435 314 opt.eliminate_null_checks();
duke@435 315 #ifndef PRODUCT
duke@435 316 if (PrintCFG || PrintCFG1) { tty->print_cr("CFG after null check elimination"); print(true); }
duke@435 317 if (PrintIR || PrintIR1 ) { tty->print_cr("IR after null check elimination"); print(false); }
duke@435 318 #endif
duke@435 319 }
duke@435 320 }
duke@435 321
duke@435 322
duke@435 323 static int sort_pairs(BlockPair** a, BlockPair** b) {
duke@435 324 if ((*a)->from() == (*b)->from()) {
duke@435 325 return (*a)->to()->block_id() - (*b)->to()->block_id();
duke@435 326 } else {
duke@435 327 return (*a)->from()->block_id() - (*b)->from()->block_id();
duke@435 328 }
duke@435 329 }
duke@435 330
duke@435 331
duke@435 332 class CriticalEdgeFinder: public BlockClosure {
duke@435 333 BlockPairList blocks;
duke@435 334 IR* _ir;
duke@435 335
duke@435 336 public:
duke@435 337 CriticalEdgeFinder(IR* ir): _ir(ir) {}
duke@435 338 void block_do(BlockBegin* bb) {
duke@435 339 BlockEnd* be = bb->end();
duke@435 340 int nos = be->number_of_sux();
duke@435 341 if (nos >= 2) {
duke@435 342 for (int i = 0; i < nos; i++) {
duke@435 343 BlockBegin* sux = be->sux_at(i);
duke@435 344 if (sux->number_of_preds() >= 2) {
duke@435 345 blocks.append(new BlockPair(bb, sux));
duke@435 346 }
duke@435 347 }
duke@435 348 }
duke@435 349 }
duke@435 350
duke@435 351 void split_edges() {
duke@435 352 BlockPair* last_pair = NULL;
duke@435 353 blocks.sort(sort_pairs);
duke@435 354 for (int i = 0; i < blocks.length(); i++) {
duke@435 355 BlockPair* pair = blocks.at(i);
duke@435 356 if (last_pair != NULL && pair->is_same(last_pair)) continue;
duke@435 357 BlockBegin* from = pair->from();
duke@435 358 BlockBegin* to = pair->to();
duke@435 359 BlockBegin* split = from->insert_block_between(to);
duke@435 360 #ifndef PRODUCT
duke@435 361 if ((PrintIR || PrintIR1) && Verbose) {
duke@435 362 tty->print_cr("Split critical edge B%d -> B%d (new block B%d)",
duke@435 363 from->block_id(), to->block_id(), split->block_id());
duke@435 364 }
duke@435 365 #endif
duke@435 366 last_pair = pair;
duke@435 367 }
duke@435 368 }
duke@435 369 };
duke@435 370
duke@435 371 void IR::split_critical_edges() {
duke@435 372 CriticalEdgeFinder cef(this);
duke@435 373
duke@435 374 iterate_preorder(&cef);
duke@435 375 cef.split_edges();
duke@435 376 }
duke@435 377
duke@435 378
iveresov@1939 379 class UseCountComputer: public ValueVisitor, BlockClosure {
duke@435 380 private:
iveresov@1939 381 void visit(Value* n) {
duke@435 382 // Local instructions and Phis for expression stack values at the
duke@435 383 // start of basic blocks are not added to the instruction list
duke@435 384 if ((*n)->bci() == -99 && (*n)->as_Local() == NULL &&
duke@435 385 (*n)->as_Phi() == NULL) {
duke@435 386 assert(false, "a node was not appended to the graph");
iveresov@1939 387 Compilation::current()->bailout("a node was not appended to the graph");
duke@435 388 }
duke@435 389 // use n's input if not visited before
duke@435 390 if (!(*n)->is_pinned() && !(*n)->has_uses()) {
duke@435 391 // note: a) if the instruction is pinned, it will be handled by compute_use_count
duke@435 392 // b) if the instruction has uses, it was touched before
duke@435 393 // => in both cases we don't need to update n's values
duke@435 394 uses_do(n);
duke@435 395 }
duke@435 396 // use n
duke@435 397 (*n)->_use_count++;
duke@435 398 }
duke@435 399
iveresov@1939 400 Values* worklist;
iveresov@1939 401 int depth;
duke@435 402 enum {
duke@435 403 max_recurse_depth = 20
duke@435 404 };
duke@435 405
iveresov@1939 406 void uses_do(Value* n) {
duke@435 407 depth++;
duke@435 408 if (depth > max_recurse_depth) {
duke@435 409 // don't allow the traversal to recurse too deeply
duke@435 410 worklist->push(*n);
duke@435 411 } else {
iveresov@1939 412 (*n)->input_values_do(this);
duke@435 413 // special handling for some instructions
duke@435 414 if ((*n)->as_BlockEnd() != NULL) {
duke@435 415 // note on BlockEnd:
duke@435 416 // must 'use' the stack only if the method doesn't
duke@435 417 // terminate, however, in those cases stack is empty
iveresov@1939 418 (*n)->state_values_do(this);
duke@435 419 }
duke@435 420 }
duke@435 421 depth--;
duke@435 422 }
duke@435 423
iveresov@1939 424 void block_do(BlockBegin* b) {
duke@435 425 depth = 0;
duke@435 426 // process all pinned nodes as the roots of expression trees
duke@435 427 for (Instruction* n = b; n != NULL; n = n->next()) {
duke@435 428 if (n->is_pinned()) uses_do(&n);
duke@435 429 }
duke@435 430 assert(depth == 0, "should have counted back down");
duke@435 431
duke@435 432 // now process any unpinned nodes which recursed too deeply
duke@435 433 while (worklist->length() > 0) {
duke@435 434 Value t = worklist->pop();
duke@435 435 if (!t->is_pinned()) {
duke@435 436 // compute the use count
duke@435 437 uses_do(&t);
duke@435 438
duke@435 439 // pin the instruction so that LIRGenerator doesn't recurse
duke@435 440 // too deeply during it's evaluation.
duke@435 441 t->pin();
duke@435 442 }
duke@435 443 }
duke@435 444 assert(depth == 0, "should have counted back down");
duke@435 445 }
duke@435 446
iveresov@1939 447 UseCountComputer() {
iveresov@1939 448 worklist = new Values();
iveresov@1939 449 depth = 0;
iveresov@1939 450 }
iveresov@1939 451
duke@435 452 public:
duke@435 453 static void compute(BlockList* blocks) {
iveresov@1939 454 UseCountComputer ucc;
iveresov@1939 455 blocks->iterate_backward(&ucc);
duke@435 456 }
duke@435 457 };
duke@435 458
duke@435 459
duke@435 460 // helper macro for short definition of trace-output inside code
duke@435 461 #ifndef PRODUCT
duke@435 462 #define TRACE_LINEAR_SCAN(level, code) \
duke@435 463 if (TraceLinearScanLevel >= level) { \
duke@435 464 code; \
duke@435 465 }
duke@435 466 #else
duke@435 467 #define TRACE_LINEAR_SCAN(level, code)
duke@435 468 #endif
duke@435 469
duke@435 470 class ComputeLinearScanOrder : public StackObj {
duke@435 471 private:
duke@435 472 int _max_block_id; // the highest block_id of a block
duke@435 473 int _num_blocks; // total number of blocks (smaller than _max_block_id)
duke@435 474 int _num_loops; // total number of loops
duke@435 475 bool _iterative_dominators;// method requires iterative computation of dominatiors
duke@435 476
duke@435 477 BlockList* _linear_scan_order; // the resulting list of blocks in correct order
duke@435 478
duke@435 479 BitMap _visited_blocks; // used for recursive processing of blocks
duke@435 480 BitMap _active_blocks; // used for recursive processing of blocks
duke@435 481 BitMap _dominator_blocks; // temproary BitMap used for computation of dominator
duke@435 482 intArray _forward_branches; // number of incoming forward branches for each block
duke@435 483 BlockList _loop_end_blocks; // list of all loop end blocks collected during count_edges
duke@435 484 BitMap2D _loop_map; // two-dimensional bit set: a bit is set if a block is contained in a loop
duke@435 485 BlockList _work_list; // temporary list (used in mark_loops and compute_order)
duke@435 486
duke@435 487 // accessors for _visited_blocks and _active_blocks
duke@435 488 void init_visited() { _active_blocks.clear(); _visited_blocks.clear(); }
duke@435 489 bool is_visited(BlockBegin* b) const { return _visited_blocks.at(b->block_id()); }
duke@435 490 bool is_active(BlockBegin* b) const { return _active_blocks.at(b->block_id()); }
duke@435 491 void set_visited(BlockBegin* b) { assert(!is_visited(b), "already set"); _visited_blocks.set_bit(b->block_id()); }
duke@435 492 void set_active(BlockBegin* b) { assert(!is_active(b), "already set"); _active_blocks.set_bit(b->block_id()); }
duke@435 493 void clear_active(BlockBegin* b) { assert(is_active(b), "not already"); _active_blocks.clear_bit(b->block_id()); }
duke@435 494
duke@435 495 // accessors for _forward_branches
duke@435 496 void inc_forward_branches(BlockBegin* b) { _forward_branches.at_put(b->block_id(), _forward_branches.at(b->block_id()) + 1); }
duke@435 497 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()); }
duke@435 498
duke@435 499 // accessors for _loop_map
duke@435 500 bool is_block_in_loop (int loop_idx, BlockBegin* b) const { return _loop_map.at(loop_idx, b->block_id()); }
duke@435 501 void set_block_in_loop (int loop_idx, BlockBegin* b) { _loop_map.set_bit(loop_idx, b->block_id()); }
duke@435 502 void clear_block_in_loop(int loop_idx, int block_id) { _loop_map.clear_bit(loop_idx, block_id); }
duke@435 503
duke@435 504 // count edges between blocks
duke@435 505 void count_edges(BlockBegin* cur, BlockBegin* parent);
duke@435 506
duke@435 507 // loop detection
duke@435 508 void mark_loops();
duke@435 509 void clear_non_natural_loops(BlockBegin* start_block);
duke@435 510 void assign_loop_depth(BlockBegin* start_block);
duke@435 511
duke@435 512 // computation of final block order
duke@435 513 BlockBegin* common_dominator(BlockBegin* a, BlockBegin* b);
duke@435 514 void compute_dominator(BlockBegin* cur, BlockBegin* parent);
duke@435 515 int compute_weight(BlockBegin* cur);
duke@435 516 bool ready_for_processing(BlockBegin* cur);
duke@435 517 void sort_into_work_list(BlockBegin* b);
duke@435 518 void append_block(BlockBegin* cur);
duke@435 519 void compute_order(BlockBegin* start_block);
duke@435 520
duke@435 521 // fixup of dominators for non-natural loops
duke@435 522 bool compute_dominators_iter();
duke@435 523 void compute_dominators();
duke@435 524
duke@435 525 // debug functions
duke@435 526 NOT_PRODUCT(void print_blocks();)
duke@435 527 DEBUG_ONLY(void verify();)
duke@435 528
duke@435 529 public:
duke@435 530 ComputeLinearScanOrder(BlockBegin* start_block);
duke@435 531
duke@435 532 // accessors for final result
duke@435 533 BlockList* linear_scan_order() const { return _linear_scan_order; }
duke@435 534 int num_loops() const { return _num_loops; }
duke@435 535 };
duke@435 536
duke@435 537
duke@435 538 ComputeLinearScanOrder::ComputeLinearScanOrder(BlockBegin* start_block) :
duke@435 539 _max_block_id(BlockBegin::number_of_blocks()),
duke@435 540 _num_blocks(0),
duke@435 541 _num_loops(0),
duke@435 542 _iterative_dominators(false),
duke@435 543 _visited_blocks(_max_block_id),
duke@435 544 _active_blocks(_max_block_id),
duke@435 545 _dominator_blocks(_max_block_id),
duke@435 546 _forward_branches(_max_block_id, 0),
duke@435 547 _loop_end_blocks(8),
duke@435 548 _work_list(8),
duke@435 549 _linear_scan_order(NULL), // initialized later with correct size
duke@435 550 _loop_map(0, 0) // initialized later with correct size
duke@435 551 {
duke@435 552 TRACE_LINEAR_SCAN(2, "***** computing linear-scan block order");
duke@435 553
duke@435 554 init_visited();
duke@435 555 count_edges(start_block, NULL);
duke@435 556
duke@435 557 if (_num_loops > 0) {
duke@435 558 mark_loops();
duke@435 559 clear_non_natural_loops(start_block);
duke@435 560 assign_loop_depth(start_block);
duke@435 561 }
duke@435 562
duke@435 563 compute_order(start_block);
duke@435 564 compute_dominators();
duke@435 565
duke@435 566 NOT_PRODUCT(print_blocks());
duke@435 567 DEBUG_ONLY(verify());
duke@435 568 }
duke@435 569
duke@435 570
duke@435 571 // Traverse the CFG:
duke@435 572 // * count total number of blocks
duke@435 573 // * count all incoming edges and backward incoming edges
duke@435 574 // * number loop header blocks
duke@435 575 // * create a list with all loop end blocks
duke@435 576 void ComputeLinearScanOrder::count_edges(BlockBegin* cur, BlockBegin* parent) {
duke@435 577 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));
duke@435 578 assert(cur->dominator() == NULL, "dominator already initialized");
duke@435 579
duke@435 580 if (is_active(cur)) {
duke@435 581 TRACE_LINEAR_SCAN(3, tty->print_cr("backward branch"));
duke@435 582 assert(is_visited(cur), "block must be visisted when block is active");
duke@435 583 assert(parent != NULL, "must have parent");
duke@435 584
duke@435 585 cur->set(BlockBegin::linear_scan_loop_header_flag);
duke@435 586 cur->set(BlockBegin::backward_branch_target_flag);
duke@435 587
duke@435 588 parent->set(BlockBegin::linear_scan_loop_end_flag);
never@863 589
never@863 590 // When a loop header is also the start of an exception handler, then the backward branch is
never@863 591 // an exception edge. Because such edges are usually critical edges which cannot be split, the
never@863 592 // loop must be excluded here from processing.
never@863 593 if (cur->is_set(BlockBegin::exception_entry_flag)) {
never@863 594 // Make sure that dominators are correct in this weird situation
never@863 595 _iterative_dominators = true;
never@863 596 return;
never@863 597 }
never@863 598 assert(parent->number_of_sux() == 1 && parent->sux_at(0) == cur,
never@863 599 "loop end blocks must have one successor (critical edges are split)");
never@863 600
duke@435 601 _loop_end_blocks.append(parent);
duke@435 602 return;
duke@435 603 }
duke@435 604
duke@435 605 // increment number of incoming forward branches
duke@435 606 inc_forward_branches(cur);
duke@435 607
duke@435 608 if (is_visited(cur)) {
duke@435 609 TRACE_LINEAR_SCAN(3, tty->print_cr("block already visited"));
duke@435 610 return;
duke@435 611 }
duke@435 612
duke@435 613 _num_blocks++;
duke@435 614 set_visited(cur);
duke@435 615 set_active(cur);
duke@435 616
duke@435 617 // recursive call for all successors
duke@435 618 int i;
duke@435 619 for (i = cur->number_of_sux() - 1; i >= 0; i--) {
duke@435 620 count_edges(cur->sux_at(i), cur);
duke@435 621 }
duke@435 622 for (i = cur->number_of_exception_handlers() - 1; i >= 0; i--) {
duke@435 623 count_edges(cur->exception_handler_at(i), cur);
duke@435 624 }
duke@435 625
duke@435 626 clear_active(cur);
duke@435 627
duke@435 628 // Each loop has a unique number.
duke@435 629 // When multiple loops are nested, assign_loop_depth assumes that the
duke@435 630 // innermost loop has the lowest number. This is guaranteed by setting
duke@435 631 // the loop number after the recursive calls for the successors above
duke@435 632 // have returned.
duke@435 633 if (cur->is_set(BlockBegin::linear_scan_loop_header_flag)) {
duke@435 634 assert(cur->loop_index() == -1, "cannot set loop-index twice");
duke@435 635 TRACE_LINEAR_SCAN(3, tty->print_cr("Block B%d is loop header of loop %d", cur->block_id(), _num_loops));
duke@435 636
duke@435 637 cur->set_loop_index(_num_loops);
duke@435 638 _num_loops++;
duke@435 639 }
duke@435 640
duke@435 641 TRACE_LINEAR_SCAN(3, tty->print_cr("Finished count_edges for block B%d", cur->block_id()));
duke@435 642 }
duke@435 643
duke@435 644
duke@435 645 void ComputeLinearScanOrder::mark_loops() {
duke@435 646 TRACE_LINEAR_SCAN(3, tty->print_cr("----- marking loops"));
duke@435 647
duke@435 648 _loop_map = BitMap2D(_num_loops, _max_block_id);
duke@435 649 _loop_map.clear();
duke@435 650
duke@435 651 for (int i = _loop_end_blocks.length() - 1; i >= 0; i--) {
duke@435 652 BlockBegin* loop_end = _loop_end_blocks.at(i);
duke@435 653 BlockBegin* loop_start = loop_end->sux_at(0);
duke@435 654 int loop_idx = loop_start->loop_index();
duke@435 655
duke@435 656 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));
duke@435 657 assert(loop_end->is_set(BlockBegin::linear_scan_loop_end_flag), "loop end flag must be set");
duke@435 658 assert(loop_end->number_of_sux() == 1, "incorrect number of successors");
duke@435 659 assert(loop_start->is_set(BlockBegin::linear_scan_loop_header_flag), "loop header flag must be set");
duke@435 660 assert(loop_idx >= 0 && loop_idx < _num_loops, "loop index not set");
duke@435 661 assert(_work_list.is_empty(), "work list must be empty before processing");
duke@435 662
duke@435 663 // add the end-block of the loop to the working list
duke@435 664 _work_list.push(loop_end);
duke@435 665 set_block_in_loop(loop_idx, loop_end);
duke@435 666 do {
duke@435 667 BlockBegin* cur = _work_list.pop();
duke@435 668
duke@435 669 TRACE_LINEAR_SCAN(3, tty->print_cr(" processing B%d", cur->block_id()));
duke@435 670 assert(is_block_in_loop(loop_idx, cur), "bit in loop map must be set when block is in work list");
duke@435 671
duke@435 672 // recursive processing of all predecessors ends when start block of loop is reached
duke@435 673 if (cur != loop_start && !cur->is_set(BlockBegin::osr_entry_flag)) {
duke@435 674 for (int j = cur->number_of_preds() - 1; j >= 0; j--) {
duke@435 675 BlockBegin* pred = cur->pred_at(j);
duke@435 676
duke@435 677 if (!is_block_in_loop(loop_idx, pred) /*&& !pred->is_set(BlockBeginosr_entry_flag)*/) {
duke@435 678 // this predecessor has not been processed yet, so add it to work list
duke@435 679 TRACE_LINEAR_SCAN(3, tty->print_cr(" pushing B%d", pred->block_id()));
duke@435 680 _work_list.push(pred);
duke@435 681 set_block_in_loop(loop_idx, pred);
duke@435 682 }
duke@435 683 }
duke@435 684 }
duke@435 685 } while (!_work_list.is_empty());
duke@435 686 }
duke@435 687 }
duke@435 688
duke@435 689
duke@435 690 // check for non-natural loops (loops where the loop header does not dominate
duke@435 691 // all other loop blocks = loops with mulitple entries).
duke@435 692 // such loops are ignored
duke@435 693 void ComputeLinearScanOrder::clear_non_natural_loops(BlockBegin* start_block) {
duke@435 694 for (int i = _num_loops - 1; i >= 0; i--) {
duke@435 695 if (is_block_in_loop(i, start_block)) {
duke@435 696 // loop i contains the entry block of the method
duke@435 697 // -> this is not a natural loop, so ignore it
duke@435 698 TRACE_LINEAR_SCAN(2, tty->print_cr("Loop %d is non-natural, so it is ignored", i));
duke@435 699
duke@435 700 for (int block_id = _max_block_id - 1; block_id >= 0; block_id--) {
duke@435 701 clear_block_in_loop(i, block_id);
duke@435 702 }
duke@435 703 _iterative_dominators = true;
duke@435 704 }
duke@435 705 }
duke@435 706 }
duke@435 707
duke@435 708 void ComputeLinearScanOrder::assign_loop_depth(BlockBegin* start_block) {
duke@435 709 TRACE_LINEAR_SCAN(3, "----- computing loop-depth and weight");
duke@435 710 init_visited();
duke@435 711
duke@435 712 assert(_work_list.is_empty(), "work list must be empty before processing");
duke@435 713 _work_list.append(start_block);
duke@435 714
duke@435 715 do {
duke@435 716 BlockBegin* cur = _work_list.pop();
duke@435 717
duke@435 718 if (!is_visited(cur)) {
duke@435 719 set_visited(cur);
duke@435 720 TRACE_LINEAR_SCAN(4, tty->print_cr("Computing loop depth for block B%d", cur->block_id()));
duke@435 721
duke@435 722 // compute loop-depth and loop-index for the block
duke@435 723 assert(cur->loop_depth() == 0, "cannot set loop-depth twice");
duke@435 724 int i;
duke@435 725 int loop_depth = 0;
duke@435 726 int min_loop_idx = -1;
duke@435 727 for (i = _num_loops - 1; i >= 0; i--) {
duke@435 728 if (is_block_in_loop(i, cur)) {
duke@435 729 loop_depth++;
duke@435 730 min_loop_idx = i;
duke@435 731 }
duke@435 732 }
duke@435 733 cur->set_loop_depth(loop_depth);
duke@435 734 cur->set_loop_index(min_loop_idx);
duke@435 735
duke@435 736 // append all unvisited successors to work list
duke@435 737 for (i = cur->number_of_sux() - 1; i >= 0; i--) {
duke@435 738 _work_list.append(cur->sux_at(i));
duke@435 739 }
duke@435 740 for (i = cur->number_of_exception_handlers() - 1; i >= 0; i--) {
duke@435 741 _work_list.append(cur->exception_handler_at(i));
duke@435 742 }
duke@435 743 }
duke@435 744 } while (!_work_list.is_empty());
duke@435 745 }
duke@435 746
duke@435 747
duke@435 748 BlockBegin* ComputeLinearScanOrder::common_dominator(BlockBegin* a, BlockBegin* b) {
duke@435 749 assert(a != NULL && b != NULL, "must have input blocks");
duke@435 750
duke@435 751 _dominator_blocks.clear();
duke@435 752 while (a != NULL) {
duke@435 753 _dominator_blocks.set_bit(a->block_id());
duke@435 754 assert(a->dominator() != NULL || a == _linear_scan_order->at(0), "dominator must be initialized");
duke@435 755 a = a->dominator();
duke@435 756 }
duke@435 757 while (b != NULL && !_dominator_blocks.at(b->block_id())) {
duke@435 758 assert(b->dominator() != NULL || b == _linear_scan_order->at(0), "dominator must be initialized");
duke@435 759 b = b->dominator();
duke@435 760 }
duke@435 761
duke@435 762 assert(b != NULL, "could not find dominator");
duke@435 763 return b;
duke@435 764 }
duke@435 765
duke@435 766 void ComputeLinearScanOrder::compute_dominator(BlockBegin* cur, BlockBegin* parent) {
duke@435 767 if (cur->dominator() == NULL) {
duke@435 768 TRACE_LINEAR_SCAN(4, tty->print_cr("DOM: initializing dominator of B%d to B%d", cur->block_id(), parent->block_id()));
duke@435 769 cur->set_dominator(parent);
duke@435 770
duke@435 771 } else if (!(cur->is_set(BlockBegin::linear_scan_loop_header_flag) && parent->is_set(BlockBegin::linear_scan_loop_end_flag))) {
duke@435 772 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()));
duke@435 773 assert(cur->number_of_preds() > 1, "");
duke@435 774 cur->set_dominator(common_dominator(cur->dominator(), parent));
duke@435 775 }
duke@435 776 }
duke@435 777
duke@435 778
duke@435 779 int ComputeLinearScanOrder::compute_weight(BlockBegin* cur) {
duke@435 780 BlockBegin* single_sux = NULL;
duke@435 781 if (cur->number_of_sux() == 1) {
duke@435 782 single_sux = cur->sux_at(0);
duke@435 783 }
duke@435 784
duke@435 785 // limit loop-depth to 15 bit (only for security reason, it will never be so big)
duke@435 786 int weight = (cur->loop_depth() & 0x7FFF) << 16;
duke@435 787
duke@435 788 // general macro for short definition of weight flags
duke@435 789 // the first instance of INC_WEIGHT_IF has the highest priority
duke@435 790 int cur_bit = 15;
duke@435 791 #define INC_WEIGHT_IF(condition) if ((condition)) { weight |= (1 << cur_bit); } cur_bit--;
duke@435 792
duke@435 793 // this is necessery for the (very rare) case that two successing blocks have
duke@435 794 // the same loop depth, but a different loop index (can happen for endless loops
duke@435 795 // with exception handlers)
duke@435 796 INC_WEIGHT_IF(!cur->is_set(BlockBegin::linear_scan_loop_header_flag));
duke@435 797
duke@435 798 // loop end blocks (blocks that end with a backward branch) are added
duke@435 799 // after all other blocks of the loop.
duke@435 800 INC_WEIGHT_IF(!cur->is_set(BlockBegin::linear_scan_loop_end_flag));
duke@435 801
duke@435 802 // critical edge split blocks are prefered because than they have a bigger
duke@435 803 // proability to be completely empty
duke@435 804 INC_WEIGHT_IF(cur->is_set(BlockBegin::critical_edge_split_flag));
duke@435 805
duke@435 806 // exceptions should not be thrown in normal control flow, so these blocks
duke@435 807 // are added as late as possible
duke@435 808 INC_WEIGHT_IF(cur->end()->as_Throw() == NULL && (single_sux == NULL || single_sux->end()->as_Throw() == NULL));
duke@435 809 INC_WEIGHT_IF(cur->end()->as_Return() == NULL && (single_sux == NULL || single_sux->end()->as_Return() == NULL));
duke@435 810
duke@435 811 // exceptions handlers are added as late as possible
duke@435 812 INC_WEIGHT_IF(!cur->is_set(BlockBegin::exception_entry_flag));
duke@435 813
duke@435 814 // guarantee that weight is > 0
duke@435 815 weight |= 1;
duke@435 816
duke@435 817 #undef INC_WEIGHT_IF
duke@435 818 assert(cur_bit >= 0, "too many flags");
duke@435 819 assert(weight > 0, "weight cannot become negative");
duke@435 820
duke@435 821 return weight;
duke@435 822 }
duke@435 823
duke@435 824 bool ComputeLinearScanOrder::ready_for_processing(BlockBegin* cur) {
duke@435 825 // Discount the edge just traveled.
duke@435 826 // When the number drops to zero, all forward branches were processed
duke@435 827 if (dec_forward_branches(cur) != 0) {
duke@435 828 return false;
duke@435 829 }
duke@435 830
duke@435 831 assert(_linear_scan_order->index_of(cur) == -1, "block already processed (block can be ready only once)");
duke@435 832 assert(_work_list.index_of(cur) == -1, "block already in work-list (block can be ready only once)");
duke@435 833 return true;
duke@435 834 }
duke@435 835
duke@435 836 void ComputeLinearScanOrder::sort_into_work_list(BlockBegin* cur) {
duke@435 837 assert(_work_list.index_of(cur) == -1, "block already in work list");
duke@435 838
duke@435 839 int cur_weight = compute_weight(cur);
duke@435 840
duke@435 841 // the linear_scan_number is used to cache the weight of a block
duke@435 842 cur->set_linear_scan_number(cur_weight);
duke@435 843
duke@435 844 #ifndef PRODUCT
duke@435 845 if (StressLinearScan) {
duke@435 846 _work_list.insert_before(0, cur);
duke@435 847 return;
duke@435 848 }
duke@435 849 #endif
duke@435 850
duke@435 851 _work_list.append(NULL); // provide space for new element
duke@435 852
duke@435 853 int insert_idx = _work_list.length() - 1;
duke@435 854 while (insert_idx > 0 && _work_list.at(insert_idx - 1)->linear_scan_number() > cur_weight) {
duke@435 855 _work_list.at_put(insert_idx, _work_list.at(insert_idx - 1));
duke@435 856 insert_idx--;
duke@435 857 }
duke@435 858 _work_list.at_put(insert_idx, cur);
duke@435 859
duke@435 860 TRACE_LINEAR_SCAN(3, tty->print_cr("Sorted B%d into worklist. new worklist:", cur->block_id()));
duke@435 861 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()));
duke@435 862
duke@435 863 #ifdef ASSERT
duke@435 864 for (int i = 0; i < _work_list.length(); i++) {
duke@435 865 assert(_work_list.at(i)->linear_scan_number() > 0, "weight not set");
duke@435 866 assert(i == 0 || _work_list.at(i - 1)->linear_scan_number() <= _work_list.at(i)->linear_scan_number(), "incorrect order in worklist");
duke@435 867 }
duke@435 868 #endif
duke@435 869 }
duke@435 870
duke@435 871 void ComputeLinearScanOrder::append_block(BlockBegin* cur) {
duke@435 872 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()));
duke@435 873 assert(_linear_scan_order->index_of(cur) == -1, "cannot add the same block twice");
duke@435 874
duke@435 875 // currently, the linear scan order and code emit order are equal.
duke@435 876 // therefore the linear_scan_number and the weight of a block must also
duke@435 877 // be equal.
duke@435 878 cur->set_linear_scan_number(_linear_scan_order->length());
duke@435 879 _linear_scan_order->append(cur);
duke@435 880 }
duke@435 881
duke@435 882 void ComputeLinearScanOrder::compute_order(BlockBegin* start_block) {
duke@435 883 TRACE_LINEAR_SCAN(3, "----- computing final block order");
duke@435 884
duke@435 885 // the start block is always the first block in the linear scan order
duke@435 886 _linear_scan_order = new BlockList(_num_blocks);
duke@435 887 append_block(start_block);
duke@435 888
duke@435 889 assert(start_block->end()->as_Base() != NULL, "start block must end with Base-instruction");
duke@435 890 BlockBegin* std_entry = ((Base*)start_block->end())->std_entry();
duke@435 891 BlockBegin* osr_entry = ((Base*)start_block->end())->osr_entry();
duke@435 892
duke@435 893 BlockBegin* sux_of_osr_entry = NULL;
duke@435 894 if (osr_entry != NULL) {
duke@435 895 // special handling for osr entry:
duke@435 896 // ignore the edge between the osr entry and its successor for processing
duke@435 897 // the osr entry block is added manually below
duke@435 898 assert(osr_entry->number_of_sux() == 1, "osr entry must have exactly one successor");
duke@435 899 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");
duke@435 900
duke@435 901 sux_of_osr_entry = osr_entry->sux_at(0);
duke@435 902 dec_forward_branches(sux_of_osr_entry);
duke@435 903
duke@435 904 compute_dominator(osr_entry, start_block);
duke@435 905 _iterative_dominators = true;
duke@435 906 }
duke@435 907 compute_dominator(std_entry, start_block);
duke@435 908
duke@435 909 // start processing with standard entry block
duke@435 910 assert(_work_list.is_empty(), "list must be empty before processing");
duke@435 911
duke@435 912 if (ready_for_processing(std_entry)) {
duke@435 913 sort_into_work_list(std_entry);
duke@435 914 } else {
duke@435 915 assert(false, "the std_entry must be ready for processing (otherwise, the method has no start block)");
duke@435 916 }
duke@435 917
duke@435 918 do {
duke@435 919 BlockBegin* cur = _work_list.pop();
duke@435 920
duke@435 921 if (cur == sux_of_osr_entry) {
duke@435 922 // the osr entry block is ignored in normal processing, it is never added to the
duke@435 923 // work list. Instead, it is added as late as possible manually here.
duke@435 924 append_block(osr_entry);
duke@435 925 compute_dominator(cur, osr_entry);
duke@435 926 }
duke@435 927 append_block(cur);
duke@435 928
duke@435 929 int i;
duke@435 930 int num_sux = cur->number_of_sux();
duke@435 931 // changed loop order to get "intuitive" order of if- and else-blocks
duke@435 932 for (i = 0; i < num_sux; i++) {
duke@435 933 BlockBegin* sux = cur->sux_at(i);
duke@435 934 compute_dominator(sux, cur);
duke@435 935 if (ready_for_processing(sux)) {
duke@435 936 sort_into_work_list(sux);
duke@435 937 }
duke@435 938 }
duke@435 939 num_sux = cur->number_of_exception_handlers();
duke@435 940 for (i = 0; i < num_sux; i++) {
duke@435 941 BlockBegin* sux = cur->exception_handler_at(i);
duke@435 942 compute_dominator(sux, cur);
duke@435 943 if (ready_for_processing(sux)) {
duke@435 944 sort_into_work_list(sux);
duke@435 945 }
duke@435 946 }
duke@435 947 } while (_work_list.length() > 0);
duke@435 948 }
duke@435 949
duke@435 950
duke@435 951 bool ComputeLinearScanOrder::compute_dominators_iter() {
duke@435 952 bool changed = false;
duke@435 953 int num_blocks = _linear_scan_order->length();
duke@435 954
duke@435 955 assert(_linear_scan_order->at(0)->dominator() == NULL, "must not have dominator");
duke@435 956 assert(_linear_scan_order->at(0)->number_of_preds() == 0, "must not have predecessors");
duke@435 957 for (int i = 1; i < num_blocks; i++) {
duke@435 958 BlockBegin* block = _linear_scan_order->at(i);
duke@435 959
duke@435 960 BlockBegin* dominator = block->pred_at(0);
duke@435 961 int num_preds = block->number_of_preds();
duke@435 962 for (int i = 1; i < num_preds; i++) {
duke@435 963 dominator = common_dominator(dominator, block->pred_at(i));
duke@435 964 }
duke@435 965
duke@435 966 if (dominator != block->dominator()) {
duke@435 967 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()));
duke@435 968
duke@435 969 block->set_dominator(dominator);
duke@435 970 changed = true;
duke@435 971 }
duke@435 972 }
duke@435 973 return changed;
duke@435 974 }
duke@435 975
duke@435 976 void ComputeLinearScanOrder::compute_dominators() {
duke@435 977 TRACE_LINEAR_SCAN(3, tty->print_cr("----- computing dominators (iterative computation reqired: %d)", _iterative_dominators));
duke@435 978
duke@435 979 // iterative computation of dominators is only required for methods with non-natural loops
duke@435 980 // and OSR-methods. For all other methods, the dominators computed when generating the
duke@435 981 // linear scan block order are correct.
duke@435 982 if (_iterative_dominators) {
duke@435 983 do {
duke@435 984 TRACE_LINEAR_SCAN(1, tty->print_cr("DOM: next iteration of fix-point calculation"));
duke@435 985 } while (compute_dominators_iter());
duke@435 986 }
duke@435 987
duke@435 988 // check that dominators are correct
duke@435 989 assert(!compute_dominators_iter(), "fix point not reached");
duke@435 990 }
duke@435 991
duke@435 992
duke@435 993 #ifndef PRODUCT
duke@435 994 void ComputeLinearScanOrder::print_blocks() {
duke@435 995 if (TraceLinearScanLevel >= 2) {
duke@435 996 tty->print_cr("----- loop information:");
duke@435 997 for (int block_idx = 0; block_idx < _linear_scan_order->length(); block_idx++) {
duke@435 998 BlockBegin* cur = _linear_scan_order->at(block_idx);
duke@435 999
duke@435 1000 tty->print("%4d: B%2d: ", cur->linear_scan_number(), cur->block_id());
duke@435 1001 for (int loop_idx = 0; loop_idx < _num_loops; loop_idx++) {
duke@435 1002 tty->print ("%d ", is_block_in_loop(loop_idx, cur));
duke@435 1003 }
duke@435 1004 tty->print_cr(" -> loop_index: %2d, loop_depth: %2d", cur->loop_index(), cur->loop_depth());
duke@435 1005 }
duke@435 1006 }
duke@435 1007
duke@435 1008 if (TraceLinearScanLevel >= 1) {
duke@435 1009 tty->print_cr("----- linear-scan block order:");
duke@435 1010 for (int block_idx = 0; block_idx < _linear_scan_order->length(); block_idx++) {
duke@435 1011 BlockBegin* cur = _linear_scan_order->at(block_idx);
duke@435 1012 tty->print("%4d: B%2d loop: %2d depth: %2d", cur->linear_scan_number(), cur->block_id(), cur->loop_index(), cur->loop_depth());
duke@435 1013
duke@435 1014 tty->print(cur->is_set(BlockBegin::exception_entry_flag) ? " ex" : " ");
duke@435 1015 tty->print(cur->is_set(BlockBegin::critical_edge_split_flag) ? " ce" : " ");
duke@435 1016 tty->print(cur->is_set(BlockBegin::linear_scan_loop_header_flag) ? " lh" : " ");
duke@435 1017 tty->print(cur->is_set(BlockBegin::linear_scan_loop_end_flag) ? " le" : " ");
duke@435 1018
duke@435 1019 if (cur->dominator() != NULL) {
duke@435 1020 tty->print(" dom: B%d ", cur->dominator()->block_id());
duke@435 1021 } else {
duke@435 1022 tty->print(" dom: NULL ");
duke@435 1023 }
duke@435 1024
duke@435 1025 if (cur->number_of_preds() > 0) {
duke@435 1026 tty->print(" preds: ");
duke@435 1027 for (int j = 0; j < cur->number_of_preds(); j++) {
duke@435 1028 BlockBegin* pred = cur->pred_at(j);
duke@435 1029 tty->print("B%d ", pred->block_id());
duke@435 1030 }
duke@435 1031 }
duke@435 1032 if (cur->number_of_sux() > 0) {
duke@435 1033 tty->print(" sux: ");
duke@435 1034 for (int j = 0; j < cur->number_of_sux(); j++) {
duke@435 1035 BlockBegin* sux = cur->sux_at(j);
duke@435 1036 tty->print("B%d ", sux->block_id());
duke@435 1037 }
duke@435 1038 }
duke@435 1039 if (cur->number_of_exception_handlers() > 0) {
duke@435 1040 tty->print(" ex: ");
duke@435 1041 for (int j = 0; j < cur->number_of_exception_handlers(); j++) {
duke@435 1042 BlockBegin* ex = cur->exception_handler_at(j);
duke@435 1043 tty->print("B%d ", ex->block_id());
duke@435 1044 }
duke@435 1045 }
duke@435 1046 tty->cr();
duke@435 1047 }
duke@435 1048 }
duke@435 1049 }
duke@435 1050 #endif
duke@435 1051
duke@435 1052 #ifdef ASSERT
duke@435 1053 void ComputeLinearScanOrder::verify() {
duke@435 1054 assert(_linear_scan_order->length() == _num_blocks, "wrong number of blocks in list");
duke@435 1055
duke@435 1056 if (StressLinearScan) {
duke@435 1057 // blocks are scrambled when StressLinearScan is used
duke@435 1058 return;
duke@435 1059 }
duke@435 1060
duke@435 1061 // check that all successors of a block have a higher linear-scan-number
duke@435 1062 // and that all predecessors of a block have a lower linear-scan-number
duke@435 1063 // (only backward branches of loops are ignored)
duke@435 1064 int i;
duke@435 1065 for (i = 0; i < _linear_scan_order->length(); i++) {
duke@435 1066 BlockBegin* cur = _linear_scan_order->at(i);
duke@435 1067
duke@435 1068 assert(cur->linear_scan_number() == i, "incorrect linear_scan_number");
duke@435 1069 assert(cur->linear_scan_number() >= 0 && cur->linear_scan_number() == _linear_scan_order->index_of(cur), "incorrect linear_scan_number");
duke@435 1070
duke@435 1071 int j;
duke@435 1072 for (j = cur->number_of_sux() - 1; j >= 0; j--) {
duke@435 1073 BlockBegin* sux = cur->sux_at(j);
duke@435 1074
duke@435 1075 assert(sux->linear_scan_number() >= 0 && sux->linear_scan_number() == _linear_scan_order->index_of(sux), "incorrect linear_scan_number");
duke@435 1076 if (!cur->is_set(BlockBegin::linear_scan_loop_end_flag)) {
duke@435 1077 assert(cur->linear_scan_number() < sux->linear_scan_number(), "invalid order");
duke@435 1078 }
duke@435 1079 if (cur->loop_depth() == sux->loop_depth()) {
duke@435 1080 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");
duke@435 1081 }
duke@435 1082 }
duke@435 1083
duke@435 1084 for (j = cur->number_of_preds() - 1; j >= 0; j--) {
duke@435 1085 BlockBegin* pred = cur->pred_at(j);
duke@435 1086
duke@435 1087 assert(pred->linear_scan_number() >= 0 && pred->linear_scan_number() == _linear_scan_order->index_of(pred), "incorrect linear_scan_number");
duke@435 1088 if (!cur->is_set(BlockBegin::linear_scan_loop_header_flag)) {
duke@435 1089 assert(cur->linear_scan_number() > pred->linear_scan_number(), "invalid order");
duke@435 1090 }
duke@435 1091 if (cur->loop_depth() == pred->loop_depth()) {
duke@435 1092 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");
duke@435 1093 }
duke@435 1094
duke@435 1095 assert(cur->dominator()->linear_scan_number() <= cur->pred_at(j)->linear_scan_number(), "dominator must be before predecessors");
duke@435 1096 }
duke@435 1097
duke@435 1098 // check dominator
duke@435 1099 if (i == 0) {
duke@435 1100 assert(cur->dominator() == NULL, "first block has no dominator");
duke@435 1101 } else {
duke@435 1102 assert(cur->dominator() != NULL, "all but first block must have dominator");
duke@435 1103 }
duke@435 1104 assert(cur->number_of_preds() != 1 || cur->dominator() == cur->pred_at(0), "Single predecessor must also be dominator");
duke@435 1105 }
duke@435 1106
duke@435 1107 // check that all loops are continuous
duke@435 1108 for (int loop_idx = 0; loop_idx < _num_loops; loop_idx++) {
duke@435 1109 int block_idx = 0;
duke@435 1110 assert(!is_block_in_loop(loop_idx, _linear_scan_order->at(block_idx)), "the first block must not be present in any loop");
duke@435 1111
duke@435 1112 // skip blocks before the loop
duke@435 1113 while (block_idx < _num_blocks && !is_block_in_loop(loop_idx, _linear_scan_order->at(block_idx))) {
duke@435 1114 block_idx++;
duke@435 1115 }
duke@435 1116 // skip blocks of loop
duke@435 1117 while (block_idx < _num_blocks && is_block_in_loop(loop_idx, _linear_scan_order->at(block_idx))) {
duke@435 1118 block_idx++;
duke@435 1119 }
duke@435 1120 // after the first non-loop block, there must not be another loop-block
duke@435 1121 while (block_idx < _num_blocks) {
duke@435 1122 assert(!is_block_in_loop(loop_idx, _linear_scan_order->at(block_idx)), "loop not continuous in linear-scan order");
duke@435 1123 block_idx++;
duke@435 1124 }
duke@435 1125 }
duke@435 1126 }
duke@435 1127 #endif
duke@435 1128
duke@435 1129
duke@435 1130 void IR::compute_code() {
duke@435 1131 assert(is_valid(), "IR must be valid");
duke@435 1132
duke@435 1133 ComputeLinearScanOrder compute_order(start());
duke@435 1134 _num_loops = compute_order.num_loops();
duke@435 1135 _code = compute_order.linear_scan_order();
duke@435 1136 }
duke@435 1137
duke@435 1138
duke@435 1139 void IR::compute_use_counts() {
duke@435 1140 // make sure all values coming out of this block get evaluated.
duke@435 1141 int num_blocks = _code->length();
duke@435 1142 for (int i = 0; i < num_blocks; i++) {
duke@435 1143 _code->at(i)->end()->state()->pin_stack_for_linear_scan();
duke@435 1144 }
duke@435 1145
duke@435 1146 // compute use counts
duke@435 1147 UseCountComputer::compute(_code);
duke@435 1148 }
duke@435 1149
duke@435 1150
duke@435 1151 void IR::iterate_preorder(BlockClosure* closure) {
duke@435 1152 assert(is_valid(), "IR must be valid");
duke@435 1153 start()->iterate_preorder(closure);
duke@435 1154 }
duke@435 1155
duke@435 1156
duke@435 1157 void IR::iterate_postorder(BlockClosure* closure) {
duke@435 1158 assert(is_valid(), "IR must be valid");
duke@435 1159 start()->iterate_postorder(closure);
duke@435 1160 }
duke@435 1161
duke@435 1162 void IR::iterate_linear_scan_order(BlockClosure* closure) {
duke@435 1163 linear_scan_order()->iterate_forward(closure);
duke@435 1164 }
duke@435 1165
duke@435 1166
duke@435 1167 #ifndef PRODUCT
duke@435 1168 class BlockPrinter: public BlockClosure {
duke@435 1169 private:
duke@435 1170 InstructionPrinter* _ip;
duke@435 1171 bool _cfg_only;
duke@435 1172 bool _live_only;
duke@435 1173
duke@435 1174 public:
duke@435 1175 BlockPrinter(InstructionPrinter* ip, bool cfg_only, bool live_only = false) {
duke@435 1176 _ip = ip;
duke@435 1177 _cfg_only = cfg_only;
duke@435 1178 _live_only = live_only;
duke@435 1179 }
duke@435 1180
duke@435 1181 virtual void block_do(BlockBegin* block) {
duke@435 1182 if (_cfg_only) {
duke@435 1183 _ip->print_instr(block); tty->cr();
duke@435 1184 } else {
duke@435 1185 block->print_block(*_ip, _live_only);
duke@435 1186 }
duke@435 1187 }
duke@435 1188 };
duke@435 1189
duke@435 1190
duke@435 1191 void IR::print(BlockBegin* start, bool cfg_only, bool live_only) {
duke@435 1192 ttyLocker ttyl;
duke@435 1193 InstructionPrinter ip(!cfg_only);
duke@435 1194 BlockPrinter bp(&ip, cfg_only, live_only);
duke@435 1195 start->iterate_preorder(&bp);
duke@435 1196 tty->cr();
duke@435 1197 }
duke@435 1198
duke@435 1199 void IR::print(bool cfg_only, bool live_only) {
duke@435 1200 if (is_valid()) {
duke@435 1201 print(start(), cfg_only, live_only);
duke@435 1202 } else {
duke@435 1203 tty->print_cr("invalid IR");
duke@435 1204 }
duke@435 1205 }
duke@435 1206
duke@435 1207
duke@435 1208 define_array(BlockListArray, BlockList*)
duke@435 1209 define_stack(BlockListList, BlockListArray)
duke@435 1210
duke@435 1211 class PredecessorValidator : public BlockClosure {
duke@435 1212 private:
duke@435 1213 BlockListList* _predecessors;
duke@435 1214 BlockList* _blocks;
duke@435 1215
duke@435 1216 static int cmp(BlockBegin** a, BlockBegin** b) {
duke@435 1217 return (*a)->block_id() - (*b)->block_id();
duke@435 1218 }
duke@435 1219
duke@435 1220 public:
duke@435 1221 PredecessorValidator(IR* hir) {
duke@435 1222 ResourceMark rm;
duke@435 1223 _predecessors = new BlockListList(BlockBegin::number_of_blocks(), NULL);
duke@435 1224 _blocks = new BlockList();
duke@435 1225
duke@435 1226 int i;
duke@435 1227 hir->start()->iterate_preorder(this);
duke@435 1228 if (hir->code() != NULL) {
duke@435 1229 assert(hir->code()->length() == _blocks->length(), "must match");
duke@435 1230 for (i = 0; i < _blocks->length(); i++) {
duke@435 1231 assert(hir->code()->contains(_blocks->at(i)), "should be in both lists");
duke@435 1232 }
duke@435 1233 }
duke@435 1234
duke@435 1235 for (i = 0; i < _blocks->length(); i++) {
duke@435 1236 BlockBegin* block = _blocks->at(i);
duke@435 1237 BlockList* preds = _predecessors->at(block->block_id());
duke@435 1238 if (preds == NULL) {
duke@435 1239 assert(block->number_of_preds() == 0, "should be the same");
duke@435 1240 continue;
duke@435 1241 }
duke@435 1242
duke@435 1243 // clone the pred list so we can mutate it
duke@435 1244 BlockList* pred_copy = new BlockList();
duke@435 1245 int j;
duke@435 1246 for (j = 0; j < block->number_of_preds(); j++) {
duke@435 1247 pred_copy->append(block->pred_at(j));
duke@435 1248 }
duke@435 1249 // sort them in the same order
duke@435 1250 preds->sort(cmp);
duke@435 1251 pred_copy->sort(cmp);
duke@435 1252 int length = MIN2(preds->length(), block->number_of_preds());
duke@435 1253 for (j = 0; j < block->number_of_preds(); j++) {
duke@435 1254 assert(preds->at(j) == pred_copy->at(j), "must match");
duke@435 1255 }
duke@435 1256
duke@435 1257 assert(preds->length() == block->number_of_preds(), "should be the same");
duke@435 1258 }
duke@435 1259 }
duke@435 1260
duke@435 1261 virtual void block_do(BlockBegin* block) {
duke@435 1262 _blocks->append(block);
duke@435 1263 BlockEnd* be = block->end();
duke@435 1264 int n = be->number_of_sux();
duke@435 1265 int i;
duke@435 1266 for (i = 0; i < n; i++) {
duke@435 1267 BlockBegin* sux = be->sux_at(i);
duke@435 1268 assert(!sux->is_set(BlockBegin::exception_entry_flag), "must not be xhandler");
duke@435 1269
duke@435 1270 BlockList* preds = _predecessors->at_grow(sux->block_id(), NULL);
duke@435 1271 if (preds == NULL) {
duke@435 1272 preds = new BlockList();
duke@435 1273 _predecessors->at_put(sux->block_id(), preds);
duke@435 1274 }
duke@435 1275 preds->append(block);
duke@435 1276 }
duke@435 1277
duke@435 1278 n = block->number_of_exception_handlers();
duke@435 1279 for (i = 0; i < n; i++) {
duke@435 1280 BlockBegin* sux = block->exception_handler_at(i);
duke@435 1281 assert(sux->is_set(BlockBegin::exception_entry_flag), "must be xhandler");
duke@435 1282
duke@435 1283 BlockList* preds = _predecessors->at_grow(sux->block_id(), NULL);
duke@435 1284 if (preds == NULL) {
duke@435 1285 preds = new BlockList();
duke@435 1286 _predecessors->at_put(sux->block_id(), preds);
duke@435 1287 }
duke@435 1288 preds->append(block);
duke@435 1289 }
duke@435 1290 }
duke@435 1291 };
duke@435 1292
duke@435 1293 void IR::verify() {
duke@435 1294 #ifdef ASSERT
duke@435 1295 PredecessorValidator pv(this);
duke@435 1296 #endif
duke@435 1297 }
duke@435 1298
duke@435 1299 #endif // PRODUCT
duke@435 1300
iveresov@1939 1301 void SubstitutionResolver::visit(Value* v) {
duke@435 1302 Value v0 = *v;
duke@435 1303 if (v0) {
duke@435 1304 Value vs = v0->subst();
duke@435 1305 if (vs != v0) {
duke@435 1306 *v = v0->subst();
duke@435 1307 }
duke@435 1308 }
duke@435 1309 }
duke@435 1310
duke@435 1311 #ifdef ASSERT
iveresov@1939 1312 class SubstitutionChecker: public ValueVisitor {
iveresov@1939 1313 void visit(Value* v) {
iveresov@1939 1314 Value v0 = *v;
iveresov@1939 1315 if (v0) {
iveresov@1939 1316 Value vs = v0->subst();
iveresov@1939 1317 assert(vs == v0, "missed substitution");
iveresov@1939 1318 }
duke@435 1319 }
iveresov@1939 1320 };
duke@435 1321 #endif
duke@435 1322
duke@435 1323
duke@435 1324 void SubstitutionResolver::block_do(BlockBegin* block) {
duke@435 1325 Instruction* last = NULL;
duke@435 1326 for (Instruction* n = block; n != NULL;) {
iveresov@1939 1327 n->values_do(this);
duke@435 1328 // need to remove this instruction from the instruction stream
duke@435 1329 if (n->subst() != n) {
duke@435 1330 assert(last != NULL, "must have last");
duke@435 1331 last->set_next(n->next(), n->next()->bci());
duke@435 1332 } else {
duke@435 1333 last = n;
duke@435 1334 }
duke@435 1335 n = last->next();
duke@435 1336 }
duke@435 1337
duke@435 1338 #ifdef ASSERT
iveresov@1939 1339 SubstitutionChecker check_substitute;
iveresov@1939 1340 if (block->state()) block->state()->values_do(&check_substitute);
iveresov@1939 1341 block->block_values_do(&check_substitute);
iveresov@1939 1342 if (block->end() && block->end()->state()) block->end()->state()->values_do(&check_substitute);
duke@435 1343 #endif
duke@435 1344 }

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