1 /*
   2  * Copyright (c) 1997, 2012, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "compiler/compileLog.hpp"
  27 #include "interpreter/linkResolver.hpp"
  28 #include "oops/method.hpp"
  29 #include "opto/addnode.hpp"
  30 #include "opto/idealGraphPrinter.hpp"
  31 #include "opto/locknode.hpp"
  32 #include "opto/memnode.hpp"
  33 #include "opto/parse.hpp"
  34 #include "opto/rootnode.hpp"
  35 #include "opto/runtime.hpp"
  36 #include "runtime/arguments.hpp"
  37 #include "runtime/handles.inline.hpp"
  38 #include "runtime/sharedRuntime.hpp"
  39 #include "utilities/copy.hpp"
  40 
  41 // Static array so we can figure out which bytecodes stop us from compiling
  42 // the most. Some of the non-static variables are needed in bytecodeInfo.cpp
  43 // and eventually should be encapsulated in a proper class (gri 8/18/98).
  44 
  45 int nodes_created              = 0;
  46 int methods_parsed             = 0;
  47 int methods_seen               = 0;
  48 int blocks_parsed              = 0;
  49 int blocks_seen                = 0;
  50 
  51 int explicit_null_checks_inserted = 0;
  52 int explicit_null_checks_elided   = 0;
  53 int all_null_checks_found         = 0, implicit_null_checks              = 0;
  54 int implicit_null_throws          = 0;
  55 
  56 int reclaim_idx  = 0;
  57 int reclaim_in   = 0;
  58 int reclaim_node = 0;
  59 
  60 #ifndef PRODUCT
  61 bool Parse::BytecodeParseHistogram::_initialized = false;
  62 uint Parse::BytecodeParseHistogram::_bytecodes_parsed [Bytecodes::number_of_codes];
  63 uint Parse::BytecodeParseHistogram::_nodes_constructed[Bytecodes::number_of_codes];
  64 uint Parse::BytecodeParseHistogram::_nodes_transformed[Bytecodes::number_of_codes];
  65 uint Parse::BytecodeParseHistogram::_new_values       [Bytecodes::number_of_codes];
  66 #endif
  67 
  68 //------------------------------print_statistics-------------------------------
  69 #ifndef PRODUCT
  70 void Parse::print_statistics() {
  71   tty->print_cr("--- Compiler Statistics ---");
  72   tty->print("Methods seen: %d  Methods parsed: %d", methods_seen, methods_parsed);
  73   tty->print("  Nodes created: %d", nodes_created);
  74   tty->cr();
  75   if (methods_seen != methods_parsed)
  76     tty->print_cr("Reasons for parse failures (NOT cumulative):");
  77   tty->print_cr("Blocks parsed: %d  Blocks seen: %d", blocks_parsed, blocks_seen);
  78 
  79   if( explicit_null_checks_inserted )
  80     tty->print_cr("%d original NULL checks - %d elided (%2d%%); optimizer leaves %d,", explicit_null_checks_inserted, explicit_null_checks_elided, (100*explicit_null_checks_elided)/explicit_null_checks_inserted, all_null_checks_found);
  81   if( all_null_checks_found )
  82     tty->print_cr("%d made implicit (%2d%%)", implicit_null_checks,
  83                   (100*implicit_null_checks)/all_null_checks_found);
  84   if( implicit_null_throws )
  85     tty->print_cr("%d implicit null exceptions at runtime",
  86                   implicit_null_throws);
  87 
  88   if( PrintParseStatistics && BytecodeParseHistogram::initialized() ) {
  89     BytecodeParseHistogram::print();
  90   }
  91 }
  92 #endif
  93 
  94 //------------------------------ON STACK REPLACEMENT---------------------------
  95 
  96 // Construct a node which can be used to get incoming state for
  97 // on stack replacement.
  98 Node *Parse::fetch_interpreter_state(int index,
  99                                      BasicType bt,
 100                                      Node *local_addrs,
 101                                      Node *local_addrs_base) {
 102   Node *mem = memory(Compile::AliasIdxRaw);
 103   Node *adr = basic_plus_adr( local_addrs_base, local_addrs, -index*wordSize );
 104   Node *ctl = control();
 105 
 106   // Very similar to LoadNode::make, except we handle un-aligned longs and
 107   // doubles on Sparc.  Intel can handle them just fine directly.
 108   Node *l;
 109   switch( bt ) {                // Signature is flattened
 110   case T_INT:     l = new (C) LoadINode( ctl, mem, adr, TypeRawPtr::BOTTOM ); break;
 111   case T_FLOAT:   l = new (C) LoadFNode( ctl, mem, adr, TypeRawPtr::BOTTOM ); break;
 112   case T_ADDRESS: l = new (C) LoadPNode( ctl, mem, adr, TypeRawPtr::BOTTOM, TypeRawPtr::BOTTOM  ); break;
 113   case T_OBJECT:  l = new (C) LoadPNode( ctl, mem, adr, TypeRawPtr::BOTTOM, TypeInstPtr::BOTTOM ); break;
 114   case T_LONG:
 115   case T_DOUBLE: {
 116     // Since arguments are in reverse order, the argument address 'adr'
 117     // refers to the back half of the long/double.  Recompute adr.
 118     adr = basic_plus_adr( local_addrs_base, local_addrs, -(index+1)*wordSize );
 119     if( Matcher::misaligned_doubles_ok ) {
 120       l = (bt == T_DOUBLE)
 121         ? (Node*)new (C) LoadDNode( ctl, mem, adr, TypeRawPtr::BOTTOM )
 122         : (Node*)new (C) LoadLNode( ctl, mem, adr, TypeRawPtr::BOTTOM );
 123     } else {
 124       l = (bt == T_DOUBLE)
 125         ? (Node*)new (C) LoadD_unalignedNode( ctl, mem, adr, TypeRawPtr::BOTTOM )
 126         : (Node*)new (C) LoadL_unalignedNode( ctl, mem, adr, TypeRawPtr::BOTTOM );
 127     }
 128     break;
 129   }
 130   default: ShouldNotReachHere();
 131   }
 132   return _gvn.transform(l);
 133 }
 134 
 135 // Helper routine to prevent the interpreter from handing
 136 // unexpected typestate to an OSR method.
 137 // The Node l is a value newly dug out of the interpreter frame.
 138 // The type is the type predicted by ciTypeFlow.  Note that it is
 139 // not a general type, but can only come from Type::get_typeflow_type.
 140 // The safepoint is a map which will feed an uncommon trap.
 141 Node* Parse::check_interpreter_type(Node* l, const Type* type,
 142                                     SafePointNode* &bad_type_exit) {
 143 
 144   const TypeOopPtr* tp = type->isa_oopptr();
 145 
 146   // TypeFlow may assert null-ness if a type appears unloaded.
 147   if (type == TypePtr::NULL_PTR ||
 148       (tp != NULL && !tp->klass()->is_loaded())) {
 149     // Value must be null, not a real oop.
 150     Node* chk = _gvn.transform( new (C) CmpPNode(l, null()) );
 151     Node* tst = _gvn.transform( new (C) BoolNode(chk, BoolTest::eq) );
 152     IfNode* iff = create_and_map_if(control(), tst, PROB_MAX, COUNT_UNKNOWN);
 153     set_control(_gvn.transform( new (C) IfTrueNode(iff) ));
 154     Node* bad_type = _gvn.transform( new (C) IfFalseNode(iff) );
 155     bad_type_exit->control()->add_req(bad_type);
 156     l = null();
 157   }
 158 
 159   // Typeflow can also cut off paths from the CFG, based on
 160   // types which appear unloaded, or call sites which appear unlinked.
 161   // When paths are cut off, values at later merge points can rise
 162   // toward more specific classes.  Make sure these specific classes
 163   // are still in effect.
 164   if (tp != NULL && tp->klass() != C->env()->Object_klass()) {
 165     // TypeFlow asserted a specific object type.  Value must have that type.
 166     Node* bad_type_ctrl = NULL;
 167     l = gen_checkcast(l, makecon(TypeKlassPtr::make(tp->klass())), &bad_type_ctrl);
 168     bad_type_exit->control()->add_req(bad_type_ctrl);
 169   }
 170 
 171   BasicType bt_l = _gvn.type(l)->basic_type();
 172   BasicType bt_t = type->basic_type();
 173   assert(_gvn.type(l)->higher_equal(type), "must constrain OSR typestate");
 174   return l;
 175 }
 176 
 177 // Helper routine which sets up elements of the initial parser map when
 178 // performing a parse for on stack replacement.  Add values into map.
 179 // The only parameter contains the address of a interpreter arguments.
 180 void Parse::load_interpreter_state(Node* osr_buf) {
 181   int index;
 182   int max_locals = jvms()->loc_size();
 183   int max_stack  = jvms()->stk_size();
 184 
 185 
 186   // Mismatch between method and jvms can occur since map briefly held
 187   // an OSR entry state (which takes up one RawPtr word).
 188   assert(max_locals == method()->max_locals(), "sanity");
 189   assert(max_stack  >= method()->max_stack(),  "sanity");
 190   assert((int)jvms()->endoff() == TypeFunc::Parms + max_locals + max_stack, "sanity");
 191   assert((int)jvms()->endoff() == (int)map()->req(), "sanity");
 192 
 193   // Find the start block.
 194   Block* osr_block = start_block();
 195   assert(osr_block->start() == osr_bci(), "sanity");
 196 
 197   // Set initial BCI.
 198   set_parse_bci(osr_block->start());
 199 
 200   // Set initial stack depth.
 201   set_sp(osr_block->start_sp());
 202 
 203   // Check bailouts.  We currently do not perform on stack replacement
 204   // of loops in catch blocks or loops which branch with a non-empty stack.
 205   if (sp() != 0) {
 206     C->record_method_not_compilable("OSR starts with non-empty stack");
 207     return;
 208   }
 209   // Do not OSR inside finally clauses:
 210   if (osr_block->has_trap_at(osr_block->start())) {
 211     C->record_method_not_compilable("OSR starts with an immediate trap");
 212     return;
 213   }
 214 
 215   // Commute monitors from interpreter frame to compiler frame.
 216   assert(jvms()->monitor_depth() == 0, "should be no active locks at beginning of osr");
 217   int mcnt = osr_block->flow()->monitor_count();
 218   Node *monitors_addr = basic_plus_adr(osr_buf, osr_buf, (max_locals+mcnt*2-1)*wordSize);
 219   for (index = 0; index < mcnt; index++) {
 220     // Make a BoxLockNode for the monitor.
 221     Node *box = _gvn.transform(new (C) BoxLockNode(next_monitor()));
 222 
 223 
 224     // Displaced headers and locked objects are interleaved in the
 225     // temp OSR buffer.  We only copy the locked objects out here.
 226     // Fetch the locked object from the OSR temp buffer and copy to our fastlock node.
 227     Node *lock_object = fetch_interpreter_state(index*2, T_OBJECT, monitors_addr, osr_buf);
 228     // Try and copy the displaced header to the BoxNode
 229     Node *displaced_hdr = fetch_interpreter_state((index*2) + 1, T_ADDRESS, monitors_addr, osr_buf);
 230 
 231 
 232     store_to_memory(control(), box, displaced_hdr, T_ADDRESS, Compile::AliasIdxRaw);
 233 
 234     // Build a bogus FastLockNode (no code will be generated) and push the
 235     // monitor into our debug info.
 236     const FastLockNode *flock = _gvn.transform(new (C) FastLockNode( 0, lock_object, box ))->as_FastLock();
 237     map()->push_monitor(flock);
 238 
 239     // If the lock is our method synchronization lock, tuck it away in
 240     // _sync_lock for return and rethrow exit paths.
 241     if (index == 0 && method()->is_synchronized()) {
 242       _synch_lock = flock;
 243     }
 244   }
 245 
 246   // Use the raw liveness computation to make sure that unexpected
 247   // values don't propagate into the OSR frame.
 248   MethodLivenessResult live_locals = method()->liveness_at_bci(osr_bci());
 249   if (!live_locals.is_valid()) {
 250     // Degenerate or breakpointed method.
 251     C->record_method_not_compilable("OSR in empty or breakpointed method");
 252     return;
 253   }
 254 
 255   // Extract the needed locals from the interpreter frame.
 256   Node *locals_addr = basic_plus_adr(osr_buf, osr_buf, (max_locals-1)*wordSize);
 257 
 258   // find all the locals that the interpreter thinks contain live oops
 259   const BitMap live_oops = method()->live_local_oops_at_bci(osr_bci());
 260   for (index = 0; index < max_locals; index++) {
 261 
 262     if (!live_locals.at(index)) {
 263       continue;
 264     }
 265 
 266     const Type *type = osr_block->local_type_at(index);
 267 
 268     if (type->isa_oopptr() != NULL) {
 269 
 270       // 6403625: Verify that the interpreter oopMap thinks that the oop is live
 271       // else we might load a stale oop if the MethodLiveness disagrees with the
 272       // result of the interpreter. If the interpreter says it is dead we agree
 273       // by making the value go to top.
 274       //
 275 
 276       if (!live_oops.at(index)) {
 277         if (C->log() != NULL) {
 278           C->log()->elem("OSR_mismatch local_index='%d'",index);
 279         }
 280         set_local(index, null());
 281         // and ignore it for the loads
 282         continue;
 283       }
 284     }
 285 
 286     // Filter out TOP, HALF, and BOTTOM.  (Cf. ensure_phi.)
 287     if (type == Type::TOP || type == Type::HALF) {
 288       continue;
 289     }
 290     // If the type falls to bottom, then this must be a local that
 291     // is mixing ints and oops or some such.  Forcing it to top
 292     // makes it go dead.
 293     if (type == Type::BOTTOM) {
 294       continue;
 295     }
 296     // Construct code to access the appropriate local.
 297     BasicType bt = type->basic_type();
 298     if (type == TypePtr::NULL_PTR) {
 299       // Ptr types are mixed together with T_ADDRESS but NULL is
 300       // really for T_OBJECT types so correct it.
 301       bt = T_OBJECT;
 302     }
 303     Node *value = fetch_interpreter_state(index, bt, locals_addr, osr_buf);
 304     set_local(index, value);
 305   }
 306 
 307   // Extract the needed stack entries from the interpreter frame.
 308   for (index = 0; index < sp(); index++) {
 309     const Type *type = osr_block->stack_type_at(index);
 310     if (type != Type::TOP) {
 311       // Currently the compiler bails out when attempting to on stack replace
 312       // at a bci with a non-empty stack.  We should not reach here.
 313       ShouldNotReachHere();
 314     }
 315   }
 316 
 317   // End the OSR migration
 318   make_runtime_call(RC_LEAF, OptoRuntime::osr_end_Type(),
 319                     CAST_FROM_FN_PTR(address, SharedRuntime::OSR_migration_end),
 320                     "OSR_migration_end", TypeRawPtr::BOTTOM,
 321                     osr_buf);
 322 
 323   // Now that the interpreter state is loaded, make sure it will match
 324   // at execution time what the compiler is expecting now:
 325   SafePointNode* bad_type_exit = clone_map();
 326   bad_type_exit->set_control(new (C) RegionNode(1));
 327 
 328   assert(osr_block->flow()->jsrs()->size() == 0, "should be no jsrs live at osr point");
 329   for (index = 0; index < max_locals; index++) {
 330     if (stopped())  break;
 331     Node* l = local(index);
 332     if (l->is_top())  continue;  // nothing here
 333     const Type *type = osr_block->local_type_at(index);
 334     if (type->isa_oopptr() != NULL) {
 335       if (!live_oops.at(index)) {
 336         // skip type check for dead oops
 337         continue;
 338       }
 339     }
 340     if (osr_block->flow()->local_type_at(index)->is_return_address()) {
 341       // In our current system it's illegal for jsr addresses to be
 342       // live into an OSR entry point because the compiler performs
 343       // inlining of jsrs.  ciTypeFlow has a bailout that detect this
 344       // case and aborts the compile if addresses are live into an OSR
 345       // entry point.  Because of that we can assume that any address
 346       // locals at the OSR entry point are dead.  Method liveness
 347       // isn't precise enought to figure out that they are dead in all
 348       // cases so simply skip checking address locals all
 349       // together. Any type check is guaranteed to fail since the
 350       // interpreter type is the result of a load which might have any
 351       // value and the expected type is a constant.
 352       continue;
 353     }
 354     set_local(index, check_interpreter_type(l, type, bad_type_exit));
 355   }
 356 
 357   for (index = 0; index < sp(); index++) {
 358     if (stopped())  break;
 359     Node* l = stack(index);
 360     if (l->is_top())  continue;  // nothing here
 361     const Type *type = osr_block->stack_type_at(index);
 362     set_stack(index, check_interpreter_type(l, type, bad_type_exit));
 363   }
 364 
 365   if (bad_type_exit->control()->req() > 1) {
 366     // Build an uncommon trap here, if any inputs can be unexpected.
 367     bad_type_exit->set_control(_gvn.transform( bad_type_exit->control() ));
 368     record_for_igvn(bad_type_exit->control());
 369     SafePointNode* types_are_good = map();
 370     set_map(bad_type_exit);
 371     // The unexpected type happens because a new edge is active
 372     // in the CFG, which typeflow had previously ignored.
 373     // E.g., Object x = coldAtFirst() && notReached()? "str": new Integer(123).
 374     // This x will be typed as Integer if notReached is not yet linked.
 375     // It could also happen due to a problem in ciTypeFlow analysis.
 376     uncommon_trap(Deoptimization::Reason_constraint,
 377                   Deoptimization::Action_reinterpret);
 378     set_map(types_are_good);
 379   }
 380 }
 381 
 382 //------------------------------Parse------------------------------------------
 383 // Main parser constructor.
 384 Parse::Parse(JVMState* caller, ciMethod* parse_method, float expected_uses, Parse* parent)
 385   : _exits(caller), _parent(parent)
 386 {
 387   // Init some variables
 388   _caller = caller;
 389   _method = parse_method;
 390   _expected_uses = expected_uses;
 391   _depth = 1 + (caller->has_method() ? caller->depth() : 0);
 392   _wrote_final = false;
 393   _alloc_with_final = NULL;
 394   _entry_bci = InvocationEntryBci;
 395   _tf = NULL;
 396   _block = NULL;
 397   debug_only(_block_count = -1);
 398   debug_only(_blocks = (Block*)-1);
 399 #ifndef PRODUCT
 400   if (PrintCompilation || PrintOpto) {
 401     // Make sure I have an inline tree, so I can print messages about it.
 402     JVMState* ilt_caller = is_osr_parse() ? caller->caller() : caller;
 403     InlineTree::find_subtree_from_root(C->ilt(), ilt_caller, parse_method);
 404   }
 405   _max_switch_depth = 0;
 406   _est_switch_depth = 0;
 407 #endif
 408 
 409   _tf = TypeFunc::make(method());
 410   _iter.reset_to_method(method());
 411   _flow = method()->get_flow_analysis();
 412   if (_flow->failing()) {
 413     C->record_method_not_compilable_all_tiers(_flow->failure_reason());
 414   }
 415 
 416 #ifndef PRODUCT
 417   if (_flow->has_irreducible_entry()) {
 418     C->set_parsed_irreducible_loop(true);
 419   }
 420 #endif
 421 
 422   if (_expected_uses <= 0) {
 423     _prof_factor = 1;
 424   } else {
 425     float prof_total = parse_method->interpreter_invocation_count();
 426     if (prof_total <= _expected_uses) {
 427       _prof_factor = 1;
 428     } else {
 429       _prof_factor = _expected_uses / prof_total;
 430     }
 431   }
 432 
 433   CompileLog* log = C->log();
 434   if (log != NULL) {
 435     log->begin_head("parse method='%d' uses='%g'",
 436                     log->identify(parse_method), expected_uses);
 437     if (depth() == 1 && C->is_osr_compilation()) {
 438       log->print(" osr_bci='%d'", C->entry_bci());
 439     }
 440     log->stamp();
 441     log->end_head();
 442   }
 443 
 444   // Accumulate deoptimization counts.
 445   // (The range_check and store_check counts are checked elsewhere.)
 446   ciMethodData* md = method()->method_data();
 447   for (uint reason = 0; reason < md->trap_reason_limit(); reason++) {
 448     uint md_count = md->trap_count(reason);
 449     if (md_count != 0) {
 450       if (md_count == md->trap_count_limit())
 451         md_count += md->overflow_trap_count();
 452       uint total_count = C->trap_count(reason);
 453       uint old_count   = total_count;
 454       total_count += md_count;
 455       // Saturate the add if it overflows.
 456       if (total_count < old_count || total_count < md_count)
 457         total_count = (uint)-1;
 458       C->set_trap_count(reason, total_count);
 459       if (log != NULL)
 460         log->elem("observe trap='%s' count='%d' total='%d'",
 461                   Deoptimization::trap_reason_name(reason),
 462                   md_count, total_count);
 463     }
 464   }
 465   // Accumulate total sum of decompilations, also.
 466   C->set_decompile_count(C->decompile_count() + md->decompile_count());
 467 
 468   _count_invocations = C->do_count_invocations();
 469   _method_data_update = C->do_method_data_update();
 470 
 471   if (log != NULL && method()->has_exception_handlers()) {
 472     log->elem("observe that='has_exception_handlers'");
 473   }
 474 
 475   assert(method()->can_be_compiled(),       "Can not parse this method, cutout earlier");
 476   assert(method()->has_balanced_monitors(), "Can not parse unbalanced monitors, cutout earlier");
 477 
 478   // Always register dependence if JVMTI is enabled, because
 479   // either breakpoint setting or hotswapping of methods may
 480   // cause deoptimization.
 481   if (C->env()->jvmti_can_hotswap_or_post_breakpoint()) {
 482     C->dependencies()->assert_evol_method(method());
 483   }
 484 
 485   methods_seen++;
 486 
 487   // Do some special top-level things.
 488   if (depth() == 1 && C->is_osr_compilation()) {
 489     _entry_bci = C->entry_bci();
 490     _flow = method()->get_osr_flow_analysis(osr_bci());
 491     if (_flow->failing()) {
 492       C->record_method_not_compilable(_flow->failure_reason());
 493 #ifndef PRODUCT
 494       if (PrintOpto && (Verbose || WizardMode)) {
 495         tty->print_cr("OSR @%d type flow bailout: %s", _entry_bci, _flow->failure_reason());
 496         if (Verbose) {
 497           method()->print();
 498           method()->print_codes();
 499           _flow->print();
 500         }
 501       }
 502 #endif
 503     }
 504     _tf = C->tf();     // the OSR entry type is different
 505   }
 506 
 507 #ifdef ASSERT
 508   if (depth() == 1) {
 509     assert(C->is_osr_compilation() == this->is_osr_parse(), "OSR in sync");
 510     if (C->tf() != tf()) {
 511       MutexLockerEx ml(Compile_lock, Mutex::_no_safepoint_check_flag);
 512       assert(C->env()->system_dictionary_modification_counter_changed(),
 513              "Must invalidate if TypeFuncs differ");
 514     }
 515   } else {
 516     assert(!this->is_osr_parse(), "no recursive OSR");
 517   }
 518 #endif
 519 
 520   methods_parsed++;
 521 #ifndef PRODUCT
 522   // add method size here to guarantee that inlined methods are added too
 523   if (TimeCompiler)
 524     _total_bytes_compiled += method()->code_size();
 525 
 526   show_parse_info();
 527 #endif
 528 
 529   if (failing()) {
 530     if (log)  log->done("parse");
 531     return;
 532   }
 533 
 534   gvn().set_type(root(), root()->bottom_type());
 535   gvn().transform(top());
 536 
 537   // Import the results of the ciTypeFlow.
 538   init_blocks();
 539 
 540   // Merge point for all normal exits
 541   build_exits();
 542 
 543   // Setup the initial JVM state map.
 544   SafePointNode* entry_map = create_entry_map();
 545 
 546   // Check for bailouts during map initialization
 547   if (failing() || entry_map == NULL) {
 548     if (log)  log->done("parse");
 549     return;
 550   }
 551 
 552   Node_Notes* caller_nn = C->default_node_notes();
 553   // Collect debug info for inlined calls unless -XX:-DebugInlinedCalls.
 554   if (DebugInlinedCalls || depth() == 1) {
 555     C->set_default_node_notes(make_node_notes(caller_nn));
 556   }
 557 
 558   if (is_osr_parse()) {
 559     Node* osr_buf = entry_map->in(TypeFunc::Parms+0);
 560     entry_map->set_req(TypeFunc::Parms+0, top());
 561     set_map(entry_map);
 562     load_interpreter_state(osr_buf);
 563   } else {
 564     set_map(entry_map);
 565     do_method_entry();
 566   }
 567 
 568   // Check for bailouts during method entry.
 569   if (failing()) {
 570     if (log)  log->done("parse");
 571     C->set_default_node_notes(caller_nn);
 572     return;
 573   }
 574 
 575   entry_map = map();  // capture any changes performed by method setup code
 576   assert(jvms()->endoff() == map()->req(), "map matches JVMS layout");
 577 
 578   // We begin parsing as if we have just encountered a jump to the
 579   // method entry.
 580   Block* entry_block = start_block();
 581   assert(entry_block->start() == (is_osr_parse() ? osr_bci() : 0), "");
 582   set_map_clone(entry_map);
 583   merge_common(entry_block, entry_block->next_path_num());
 584 
 585 #ifndef PRODUCT
 586   BytecodeParseHistogram *parse_histogram_obj = new (C->env()->arena()) BytecodeParseHistogram(this, C);
 587   set_parse_histogram( parse_histogram_obj );
 588 #endif
 589 
 590   // Parse all the basic blocks.
 591   do_all_blocks();
 592 
 593   C->set_default_node_notes(caller_nn);
 594 
 595   // Check for bailouts during conversion to graph
 596   if (failing()) {
 597     if (log)  log->done("parse");
 598     return;
 599   }
 600 
 601   // Fix up all exiting control flow.
 602   set_map(entry_map);
 603   do_exits();
 604 
 605   if (log)  log->done("parse nodes='%d' live='%d' memory='%d'",
 606                       C->unique(), C->live_nodes(), C->node_arena()->used());
 607 }
 608 
 609 //---------------------------do_all_blocks-------------------------------------
 610 void Parse::do_all_blocks() {
 611   bool has_irreducible = flow()->has_irreducible_entry();
 612 
 613   // Walk over all blocks in Reverse Post-Order.
 614   while (true) {
 615     bool progress = false;
 616     for (int rpo = 0; rpo < block_count(); rpo++) {
 617       Block* block = rpo_at(rpo);
 618 
 619       if (block->is_parsed()) continue;
 620 
 621       if (!block->is_merged()) {
 622         // Dead block, no state reaches this block
 623         continue;
 624       }
 625 
 626       // Prepare to parse this block.
 627       load_state_from(block);
 628 
 629       if (stopped()) {
 630         // Block is dead.
 631         continue;
 632       }
 633 
 634       blocks_parsed++;
 635 
 636       progress = true;
 637       if (block->is_loop_head() || block->is_handler() || has_irreducible && !block->is_ready()) {
 638         // Not all preds have been parsed.  We must build phis everywhere.
 639         // (Note that dead locals do not get phis built, ever.)
 640         ensure_phis_everywhere();
 641 
 642         if (block->is_SEL_head() &&
 643             (UseLoopPredicate || LoopLimitCheck)) {
 644           // Add predicate to single entry (not irreducible) loop head.
 645           assert(!block->has_merged_backedge(), "only entry paths should be merged for now");
 646           // Need correct bci for predicate.
 647           // It is fine to set it here since do_one_block() will set it anyway.
 648           set_parse_bci(block->start());
 649           add_predicate();
 650           // Add new region for back branches.
 651           int edges = block->pred_count() - block->preds_parsed() + 1; // +1 for original region
 652           RegionNode *r = new (C) RegionNode(edges+1);
 653           _gvn.set_type(r, Type::CONTROL);
 654           record_for_igvn(r);
 655           r->init_req(edges, control());
 656           set_control(r);
 657           // Add new phis.
 658           ensure_phis_everywhere();
 659         }
 660 
 661         // Leave behind an undisturbed copy of the map, for future merges.
 662         set_map(clone_map());
 663       }
 664 
 665       if (control()->is_Region() && !block->is_loop_head() && !has_irreducible && !block->is_handler()) {
 666         // In the absence of irreducible loops, the Region and Phis
 667         // associated with a merge that doesn't involve a backedge can
 668         // be simplified now since the RPO parsing order guarantees
 669         // that any path which was supposed to reach here has already
 670         // been parsed or must be dead.
 671         Node* c = control();
 672         Node* result = _gvn.transform_no_reclaim(control());
 673         if (c != result && TraceOptoParse) {
 674           tty->print_cr("Block #%d replace %d with %d", block->rpo(), c->_idx, result->_idx);
 675         }
 676         if (result != top()) {
 677           record_for_igvn(result);
 678         }
 679       }
 680 
 681       // Parse the block.
 682       do_one_block();
 683 
 684       // Check for bailouts.
 685       if (failing())  return;
 686     }
 687 
 688     // with irreducible loops multiple passes might be necessary to parse everything
 689     if (!has_irreducible || !progress) {
 690       break;
 691     }
 692   }
 693 
 694   blocks_seen += block_count();
 695 
 696 #ifndef PRODUCT
 697   // Make sure there are no half-processed blocks remaining.
 698   // Every remaining unprocessed block is dead and may be ignored now.
 699   for (int rpo = 0; rpo < block_count(); rpo++) {
 700     Block* block = rpo_at(rpo);
 701     if (!block->is_parsed()) {
 702       if (TraceOptoParse) {
 703         tty->print_cr("Skipped dead block %d at bci:%d", rpo, block->start());
 704       }
 705       assert(!block->is_merged(), "no half-processed blocks");
 706     }
 707   }
 708 #endif
 709 }
 710 
 711 //-------------------------------build_exits----------------------------------
 712 // Build normal and exceptional exit merge points.
 713 void Parse::build_exits() {
 714   // make a clone of caller to prevent sharing of side-effects
 715   _exits.set_map(_exits.clone_map());
 716   _exits.clean_stack(_exits.sp());
 717   _exits.sync_jvms();
 718 
 719   RegionNode* region = new (C) RegionNode(1);
 720   record_for_igvn(region);
 721   gvn().set_type_bottom(region);
 722   _exits.set_control(region);
 723 
 724   // Note:  iophi and memphi are not transformed until do_exits.
 725   Node* iophi  = new (C) PhiNode(region, Type::ABIO);
 726   Node* memphi = new (C) PhiNode(region, Type::MEMORY, TypePtr::BOTTOM);
 727   gvn().set_type_bottom(iophi);
 728   gvn().set_type_bottom(memphi);
 729   _exits.set_i_o(iophi);
 730   _exits.set_all_memory(memphi);
 731 
 732   // Add a return value to the exit state.  (Do not push it yet.)
 733   if (tf()->range()->cnt() > TypeFunc::Parms) {
 734     const Type* ret_type = tf()->range()->field_at(TypeFunc::Parms);
 735     // Don't "bind" an unloaded return klass to the ret_phi. If the klass
 736     // becomes loaded during the subsequent parsing, the loaded and unloaded
 737     // types will not join when we transform and push in do_exits().
 738     const TypeOopPtr* ret_oop_type = ret_type->isa_oopptr();
 739     if (ret_oop_type && !ret_oop_type->klass()->is_loaded()) {
 740       ret_type = TypeOopPtr::BOTTOM;
 741     }
 742     int         ret_size = type2size[ret_type->basic_type()];
 743     Node*       ret_phi  = new (C) PhiNode(region, ret_type);
 744     gvn().set_type_bottom(ret_phi);
 745     _exits.ensure_stack(ret_size);
 746     assert((int)(tf()->range()->cnt() - TypeFunc::Parms) == ret_size, "good tf range");
 747     assert(method()->return_type()->size() == ret_size, "tf agrees w/ method");
 748     _exits.set_argument(0, ret_phi);  // here is where the parser finds it
 749     // Note:  ret_phi is not yet pushed, until do_exits.
 750   }
 751 }
 752 
 753 
 754 //----------------------------build_start_state-------------------------------
 755 // Construct a state which contains only the incoming arguments from an
 756 // unknown caller.  The method & bci will be NULL & InvocationEntryBci.
 757 JVMState* Compile::build_start_state(StartNode* start, const TypeFunc* tf) {
 758   int        arg_size = tf->domain()->cnt();
 759   int        max_size = MAX2(arg_size, (int)tf->range()->cnt());
 760   JVMState*  jvms     = new (this) JVMState(max_size - TypeFunc::Parms);
 761   SafePointNode* map  = new (this) SafePointNode(max_size, NULL);
 762   record_for_igvn(map);
 763   assert(arg_size == TypeFunc::Parms + (is_osr_compilation() ? 1 : method()->arg_size()), "correct arg_size");
 764   Node_Notes* old_nn = default_node_notes();
 765   if (old_nn != NULL && has_method()) {
 766     Node_Notes* entry_nn = old_nn->clone(this);
 767     JVMState* entry_jvms = new(this) JVMState(method(), old_nn->jvms());
 768     entry_jvms->set_offsets(0);
 769     entry_jvms->set_bci(entry_bci());
 770     entry_nn->set_jvms(entry_jvms);
 771     set_default_node_notes(entry_nn);
 772   }
 773   uint i;
 774   for (i = 0; i < (uint)arg_size; i++) {
 775     Node* parm = initial_gvn()->transform(new (this) ParmNode(start, i));
 776     map->init_req(i, parm);
 777     // Record all these guys for later GVN.
 778     record_for_igvn(parm);
 779   }
 780   for (; i < map->req(); i++) {
 781     map->init_req(i, top());
 782   }
 783   assert(jvms->argoff() == TypeFunc::Parms, "parser gets arguments here");
 784   set_default_node_notes(old_nn);
 785   map->set_jvms(jvms);
 786   jvms->set_map(map);
 787   return jvms;
 788 }
 789 
 790 //-----------------------------make_node_notes---------------------------------
 791 Node_Notes* Parse::make_node_notes(Node_Notes* caller_nn) {
 792   if (caller_nn == NULL)  return NULL;
 793   Node_Notes* nn = caller_nn->clone(C);
 794   JVMState* caller_jvms = nn->jvms();
 795   JVMState* jvms = new (C) JVMState(method(), caller_jvms);
 796   jvms->set_offsets(0);
 797   jvms->set_bci(_entry_bci);
 798   nn->set_jvms(jvms);
 799   return nn;
 800 }
 801 
 802 
 803 //--------------------------return_values--------------------------------------
 804 void Compile::return_values(JVMState* jvms) {
 805   GraphKit kit(jvms);
 806   Node* ret = new (this) ReturnNode(TypeFunc::Parms,
 807                              kit.control(),
 808                              kit.i_o(),
 809                              kit.reset_memory(),
 810                              kit.frameptr(),
 811                              kit.returnadr());
 812   // Add zero or 1 return values
 813   int ret_size = tf()->range()->cnt() - TypeFunc::Parms;
 814   if (ret_size > 0) {
 815     kit.inc_sp(-ret_size);  // pop the return value(s)
 816     kit.sync_jvms();
 817     ret->add_req(kit.argument(0));
 818     // Note:  The second dummy edge is not needed by a ReturnNode.
 819   }
 820   // bind it to root
 821   root()->add_req(ret);
 822   record_for_igvn(ret);
 823   initial_gvn()->transform_no_reclaim(ret);
 824 }
 825 
 826 //------------------------rethrow_exceptions-----------------------------------
 827 // Bind all exception states in the list into a single RethrowNode.
 828 void Compile::rethrow_exceptions(JVMState* jvms) {
 829   GraphKit kit(jvms);
 830   if (!kit.has_exceptions())  return;  // nothing to generate
 831   // Load my combined exception state into the kit, with all phis transformed:
 832   SafePointNode* ex_map = kit.combine_and_pop_all_exception_states();
 833   Node* ex_oop = kit.use_exception_state(ex_map);
 834   RethrowNode* exit = new (this) RethrowNode(kit.control(),
 835                                       kit.i_o(), kit.reset_memory(),
 836                                       kit.frameptr(), kit.returnadr(),
 837                                       // like a return but with exception input
 838                                       ex_oop);
 839   // bind to root
 840   root()->add_req(exit);
 841   record_for_igvn(exit);
 842   initial_gvn()->transform_no_reclaim(exit);
 843 }
 844 
 845 //---------------------------do_exceptions-------------------------------------
 846 // Process exceptions arising from the current bytecode.
 847 // Send caught exceptions to the proper handler within this method.
 848 // Unhandled exceptions feed into _exit.
 849 void Parse::do_exceptions() {
 850   if (!has_exceptions())  return;
 851 
 852   if (failing()) {
 853     // Pop them all off and throw them away.
 854     while (pop_exception_state() != NULL) ;
 855     return;
 856   }
 857 
 858   PreserveJVMState pjvms(this, false);
 859 
 860   SafePointNode* ex_map;
 861   while ((ex_map = pop_exception_state()) != NULL) {
 862     if (!method()->has_exception_handlers()) {
 863       // Common case:  Transfer control outward.
 864       // Doing it this early allows the exceptions to common up
 865       // even between adjacent method calls.
 866       throw_to_exit(ex_map);
 867     } else {
 868       // Have to look at the exception first.
 869       assert(stopped(), "catch_inline_exceptions trashes the map");
 870       catch_inline_exceptions(ex_map);
 871       stop_and_kill_map();      // we used up this exception state; kill it
 872     }
 873   }
 874 
 875   // We now return to our regularly scheduled program:
 876 }
 877 
 878 //---------------------------throw_to_exit-------------------------------------
 879 // Merge the given map into an exception exit from this method.
 880 // The exception exit will handle any unlocking of receiver.
 881 // The ex_oop must be saved within the ex_map, unlike merge_exception.
 882 void Parse::throw_to_exit(SafePointNode* ex_map) {
 883   // Pop the JVMS to (a copy of) the caller.
 884   GraphKit caller;
 885   caller.set_map_clone(_caller->map());
 886   caller.set_bci(_caller->bci());
 887   caller.set_sp(_caller->sp());
 888   // Copy out the standard machine state:
 889   for (uint i = 0; i < TypeFunc::Parms; i++) {
 890     caller.map()->set_req(i, ex_map->in(i));
 891   }
 892   // ...and the exception:
 893   Node*          ex_oop        = saved_ex_oop(ex_map);
 894   SafePointNode* caller_ex_map = caller.make_exception_state(ex_oop);
 895   // Finally, collect the new exception state in my exits:
 896   _exits.add_exception_state(caller_ex_map);
 897 }
 898 
 899 //------------------------------do_exits---------------------------------------
 900 void Parse::do_exits() {
 901   set_parse_bci(InvocationEntryBci);
 902 
 903   // Now peephole on the return bits
 904   Node* region = _exits.control();
 905   _exits.set_control(gvn().transform(region));
 906 
 907   Node* iophi = _exits.i_o();
 908   _exits.set_i_o(gvn().transform(iophi));
 909 
 910   if (wrote_final()) {
 911     // This method (which must be a constructor by the rules of Java)
 912     // wrote a final.  The effects of all initializations must be
 913     // committed to memory before any code after the constructor
 914     // publishes the reference to the newly constructor object.
 915     // Rather than wait for the publication, we simply block the
 916     // writes here.  Rather than put a barrier on only those writes
 917     // which are required to complete, we force all writes to complete.
 918     //
 919     // "All bets are off" unless the first publication occurs after a
 920     // normal return from the constructor.  We do not attempt to detect
 921     // such unusual early publications.  But no barrier is needed on
 922     // exceptional returns, since they cannot publish normally.
 923     //
 924     _exits.insert_mem_bar(Op_MemBarRelease, alloc_with_final());
 925 #ifndef PRODUCT
 926     if (PrintOpto && (Verbose || WizardMode)) {
 927       method()->print_name();
 928       tty->print_cr(" writes finals and needs a memory barrier");
 929     }
 930 #endif
 931   }
 932 
 933   for (MergeMemStream mms(_exits.merged_memory()); mms.next_non_empty(); ) {
 934     // transform each slice of the original memphi:
 935     mms.set_memory(_gvn.transform(mms.memory()));
 936   }
 937 
 938   if (tf()->range()->cnt() > TypeFunc::Parms) {
 939     const Type* ret_type = tf()->range()->field_at(TypeFunc::Parms);
 940     Node*       ret_phi  = _gvn.transform( _exits.argument(0) );
 941     assert(_exits.control()->is_top() || !_gvn.type(ret_phi)->empty(), "return value must be well defined");
 942     _exits.push_node(ret_type->basic_type(), ret_phi);
 943   }
 944 
 945   // Note:  Logic for creating and optimizing the ReturnNode is in Compile.
 946 
 947   // Unlock along the exceptional paths.
 948   // This is done late so that we can common up equivalent exceptions
 949   // (e.g., null checks) arising from multiple points within this method.
 950   // See GraphKit::add_exception_state, which performs the commoning.
 951   bool do_synch = method()->is_synchronized() && GenerateSynchronizationCode;
 952 
 953   // record exit from a method if compiled while Dtrace is turned on.
 954   if (do_synch || C->env()->dtrace_method_probes()) {
 955     // First move the exception list out of _exits:
 956     GraphKit kit(_exits.transfer_exceptions_into_jvms());
 957     SafePointNode* normal_map = kit.map();  // keep this guy safe
 958     // Now re-collect the exceptions into _exits:
 959     SafePointNode* ex_map;
 960     while ((ex_map = kit.pop_exception_state()) != NULL) {
 961       Node* ex_oop = kit.use_exception_state(ex_map);
 962       // Force the exiting JVM state to have this method at InvocationEntryBci.
 963       // The exiting JVM state is otherwise a copy of the calling JVMS.
 964       JVMState* caller = kit.jvms();
 965       JVMState* ex_jvms = caller->clone_shallow(C);
 966       ex_jvms->set_map(kit.clone_map());
 967       ex_jvms->map()->set_jvms(ex_jvms);
 968       ex_jvms->set_bci(   InvocationEntryBci);
 969       kit.set_jvms(ex_jvms);
 970       if (do_synch) {
 971         // Add on the synchronized-method box/object combo
 972         kit.map()->push_monitor(_synch_lock);
 973         // Unlock!
 974         kit.shared_unlock(_synch_lock->box_node(), _synch_lock->obj_node());
 975       }
 976       if (C->env()->dtrace_method_probes()) {
 977         kit.make_dtrace_method_exit(method());
 978       }
 979       // Done with exception-path processing.
 980       ex_map = kit.make_exception_state(ex_oop);
 981       assert(ex_jvms->same_calls_as(ex_map->jvms()), "sanity");
 982       // Pop the last vestige of this method:
 983       ex_map->set_jvms(caller->clone_shallow(C));
 984       ex_map->jvms()->set_map(ex_map);
 985       _exits.push_exception_state(ex_map);
 986     }
 987     assert(_exits.map() == normal_map, "keep the same return state");
 988   }
 989 
 990   {
 991     // Capture very early exceptions (receiver null checks) from caller JVMS
 992     GraphKit caller(_caller);
 993     SafePointNode* ex_map;
 994     while ((ex_map = caller.pop_exception_state()) != NULL) {
 995       _exits.add_exception_state(ex_map);
 996     }
 997   }
 998 }
 999 
1000 //-----------------------------create_entry_map-------------------------------
1001 // Initialize our parser map to contain the types at method entry.
1002 // For OSR, the map contains a single RawPtr parameter.
1003 // Initial monitor locking for sync. methods is performed by do_method_entry.
1004 SafePointNode* Parse::create_entry_map() {
1005   // Check for really stupid bail-out cases.
1006   uint len = TypeFunc::Parms + method()->max_locals() + method()->max_stack();
1007   if (len >= 32760) {
1008     C->record_method_not_compilable_all_tiers("too many local variables");
1009     return NULL;
1010   }
1011 
1012   // If this is an inlined method, we may have to do a receiver null check.
1013   if (_caller->has_method() && is_normal_parse() && !method()->is_static()) {
1014     GraphKit kit(_caller);
1015     kit.null_check_receiver_before_call(method());
1016     _caller = kit.transfer_exceptions_into_jvms();
1017     if (kit.stopped()) {
1018       _exits.add_exception_states_from(_caller);
1019       _exits.set_jvms(_caller);
1020       return NULL;
1021     }
1022   }
1023 
1024   assert(method() != NULL, "parser must have a method");
1025 
1026   // Create an initial safepoint to hold JVM state during parsing
1027   JVMState* jvms = new (C) JVMState(method(), _caller->has_method() ? _caller : NULL);
1028   set_map(new (C) SafePointNode(len, jvms));
1029   jvms->set_map(map());
1030   record_for_igvn(map());
1031   assert(jvms->endoff() == len, "correct jvms sizing");
1032 
1033   SafePointNode* inmap = _caller->map();
1034   assert(inmap != NULL, "must have inmap");
1035 
1036   uint i;
1037 
1038   // Pass thru the predefined input parameters.
1039   for (i = 0; i < TypeFunc::Parms; i++) {
1040     map()->init_req(i, inmap->in(i));
1041   }
1042 
1043   if (depth() == 1) {
1044     assert(map()->memory()->Opcode() == Op_Parm, "");
1045     // Insert the memory aliasing node
1046     set_all_memory(reset_memory());
1047   }
1048   assert(merged_memory(), "");
1049 
1050   // Now add the locals which are initially bound to arguments:
1051   uint arg_size = tf()->domain()->cnt();
1052   ensure_stack(arg_size - TypeFunc::Parms);  // OSR methods have funny args
1053   for (i = TypeFunc::Parms; i < arg_size; i++) {
1054     map()->init_req(i, inmap->argument(_caller, i - TypeFunc::Parms));
1055   }
1056 
1057   // Clear out the rest of the map (locals and stack)
1058   for (i = arg_size; i < len; i++) {
1059     map()->init_req(i, top());
1060   }
1061 
1062   SafePointNode* entry_map = stop();
1063   return entry_map;
1064 }
1065 
1066 //-----------------------------do_method_entry--------------------------------
1067 // Emit any code needed in the pseudo-block before BCI zero.
1068 // The main thing to do is lock the receiver of a synchronized method.
1069 void Parse::do_method_entry() {
1070   set_parse_bci(InvocationEntryBci); // Pseudo-BCP
1071   set_sp(0);                      // Java Stack Pointer
1072 
1073   NOT_PRODUCT( count_compiled_calls(true/*at_method_entry*/, false/*is_inline*/); )
1074 
1075   if (C->env()->dtrace_method_probes()) {
1076     make_dtrace_method_entry(method());
1077   }
1078 
1079   // If the method is synchronized, we need to construct a lock node, attach
1080   // it to the Start node, and pin it there.
1081   if (method()->is_synchronized()) {
1082     // Insert a FastLockNode right after the Start which takes as arguments
1083     // the current thread pointer, the "this" pointer & the address of the
1084     // stack slot pair used for the lock.  The "this" pointer is a projection
1085     // off the start node, but the locking spot has to be constructed by
1086     // creating a ConLNode of 0, and boxing it with a BoxLockNode.  The BoxLockNode
1087     // becomes the second argument to the FastLockNode call.  The
1088     // FastLockNode becomes the new control parent to pin it to the start.
1089 
1090     // Setup Object Pointer
1091     Node *lock_obj = NULL;
1092     if(method()->is_static()) {
1093       ciInstance* mirror = _method->holder()->java_mirror();
1094       const TypeInstPtr *t_lock = TypeInstPtr::make(mirror);
1095       lock_obj = makecon(t_lock);
1096     } else {                  // Else pass the "this" pointer,
1097       lock_obj = local(0);    // which is Parm0 from StartNode
1098     }
1099     // Clear out dead values from the debug info.
1100     kill_dead_locals();
1101     // Build the FastLockNode
1102     _synch_lock = shared_lock(lock_obj);
1103   }
1104 
1105   if (depth() == 1) {
1106     increment_and_test_invocation_counter(Tier2CompileThreshold);
1107   }
1108 }
1109 
1110 //------------------------------init_blocks------------------------------------
1111 // Initialize our parser map to contain the types/monitors at method entry.
1112 void Parse::init_blocks() {
1113   // Create the blocks.
1114   _block_count = flow()->block_count();
1115   _blocks = NEW_RESOURCE_ARRAY(Block, _block_count);
1116   Copy::zero_to_bytes(_blocks, sizeof(Block)*_block_count);
1117 
1118   int rpo;
1119 
1120   // Initialize the structs.
1121   for (rpo = 0; rpo < block_count(); rpo++) {
1122     Block* block = rpo_at(rpo);
1123     block->init_node(this, rpo);
1124   }
1125 
1126   // Collect predecessor and successor information.
1127   for (rpo = 0; rpo < block_count(); rpo++) {
1128     Block* block = rpo_at(rpo);
1129     block->init_graph(this);
1130   }
1131 }
1132 
1133 //-------------------------------init_node-------------------------------------
1134 void Parse::Block::init_node(Parse* outer, int rpo) {
1135   _flow = outer->flow()->rpo_at(rpo);
1136   _pred_count = 0;
1137   _preds_parsed = 0;
1138   _count = 0;
1139   assert(pred_count() == 0 && preds_parsed() == 0, "sanity");
1140   assert(!(is_merged() || is_parsed() || is_handler() || has_merged_backedge()), "sanity");
1141   assert(_live_locals.size() == 0, "sanity");
1142 
1143   // entry point has additional predecessor
1144   if (flow()->is_start())  _pred_count++;
1145   assert(flow()->is_start() == (this == outer->start_block()), "");
1146 }
1147 
1148 //-------------------------------init_graph------------------------------------
1149 void Parse::Block::init_graph(Parse* outer) {
1150   // Create the successor list for this parser block.
1151   GrowableArray<ciTypeFlow::Block*>* tfs = flow()->successors();
1152   GrowableArray<ciTypeFlow::Block*>* tfe = flow()->exceptions();
1153   int ns = tfs->length();
1154   int ne = tfe->length();
1155   _num_successors = ns;
1156   _all_successors = ns+ne;
1157   _successors = (ns+ne == 0) ? NULL : NEW_RESOURCE_ARRAY(Block*, ns+ne);
1158   int p = 0;
1159   for (int i = 0; i < ns+ne; i++) {
1160     ciTypeFlow::Block* tf2 = (i < ns) ? tfs->at(i) : tfe->at(i-ns);
1161     Block* block2 = outer->rpo_at(tf2->rpo());
1162     _successors[i] = block2;
1163 
1164     // Accumulate pred info for the other block, too.
1165     if (i < ns) {
1166       block2->_pred_count++;
1167     } else {
1168       block2->_is_handler = true;
1169     }
1170 
1171     #ifdef ASSERT
1172     // A block's successors must be distinguishable by BCI.
1173     // That is, no bytecode is allowed to branch to two different
1174     // clones of the same code location.
1175     for (int j = 0; j < i; j++) {
1176       Block* block1 = _successors[j];
1177       if (block1 == block2)  continue;  // duplicates are OK
1178       assert(block1->start() != block2->start(), "successors have unique bcis");
1179     }
1180     #endif
1181   }
1182 
1183   // Note: We never call next_path_num along exception paths, so they
1184   // never get processed as "ready".  Also, the input phis of exception
1185   // handlers get specially processed, so that
1186 }
1187 
1188 //---------------------------successor_for_bci---------------------------------
1189 Parse::Block* Parse::Block::successor_for_bci(int bci) {
1190   for (int i = 0; i < all_successors(); i++) {
1191     Block* block2 = successor_at(i);
1192     if (block2->start() == bci)  return block2;
1193   }
1194   // We can actually reach here if ciTypeFlow traps out a block
1195   // due to an unloaded class, and concurrently with compilation the
1196   // class is then loaded, so that a later phase of the parser is
1197   // able to see more of the bytecode CFG.  Or, the flow pass and
1198   // the parser can have a minor difference of opinion about executability
1199   // of bytecodes.  For example, "obj.field = null" is executable even
1200   // if the field's type is an unloaded class; the flow pass used to
1201   // make a trap for such code.
1202   return NULL;
1203 }
1204 
1205 
1206 //-----------------------------stack_type_at-----------------------------------
1207 const Type* Parse::Block::stack_type_at(int i) const {
1208   return get_type(flow()->stack_type_at(i));
1209 }
1210 
1211 
1212 //-----------------------------local_type_at-----------------------------------
1213 const Type* Parse::Block::local_type_at(int i) const {
1214   // Make dead locals fall to bottom.
1215   if (_live_locals.size() == 0) {
1216     MethodLivenessResult live_locals = flow()->outer()->method()->liveness_at_bci(start());
1217     // This bitmap can be zero length if we saw a breakpoint.
1218     // In such cases, pretend they are all live.
1219     ((Block*)this)->_live_locals = live_locals;
1220   }
1221   if (_live_locals.size() > 0 && !_live_locals.at(i))
1222     return Type::BOTTOM;
1223 
1224   return get_type(flow()->local_type_at(i));
1225 }
1226 
1227 
1228 #ifndef PRODUCT
1229 
1230 //----------------------------name_for_bc--------------------------------------
1231 // helper method for BytecodeParseHistogram
1232 static const char* name_for_bc(int i) {
1233   return Bytecodes::is_defined(i) ? Bytecodes::name(Bytecodes::cast(i)) : "xxxunusedxxx";
1234 }
1235 
1236 //----------------------------BytecodeParseHistogram------------------------------------
1237 Parse::BytecodeParseHistogram::BytecodeParseHistogram(Parse *p, Compile *c) {
1238   _parser   = p;
1239   _compiler = c;
1240   if( ! _initialized ) { _initialized = true; reset(); }
1241 }
1242 
1243 //----------------------------current_count------------------------------------
1244 int Parse::BytecodeParseHistogram::current_count(BPHType bph_type) {
1245   switch( bph_type ) {
1246   case BPH_transforms: { return _parser->gvn().made_progress(); }
1247   case BPH_values:     { return _parser->gvn().made_new_values(); }
1248   default: { ShouldNotReachHere(); return 0; }
1249   }
1250 }
1251 
1252 //----------------------------initialized--------------------------------------
1253 bool Parse::BytecodeParseHistogram::initialized() { return _initialized; }
1254 
1255 //----------------------------reset--------------------------------------------
1256 void Parse::BytecodeParseHistogram::reset() {
1257   int i = Bytecodes::number_of_codes;
1258   while (i-- > 0) { _bytecodes_parsed[i] = 0; _nodes_constructed[i] = 0; _nodes_transformed[i] = 0; _new_values[i] = 0; }
1259 }
1260 
1261 //----------------------------set_initial_state--------------------------------
1262 // Record info when starting to parse one bytecode
1263 void Parse::BytecodeParseHistogram::set_initial_state( Bytecodes::Code bc ) {
1264   if( PrintParseStatistics && !_parser->is_osr_parse() ) {
1265     _initial_bytecode    = bc;
1266     _initial_node_count  = _compiler->unique();
1267     _initial_transforms  = current_count(BPH_transforms);
1268     _initial_values      = current_count(BPH_values);
1269   }
1270 }
1271 
1272 //----------------------------record_change--------------------------------
1273 // Record results of parsing one bytecode
1274 void Parse::BytecodeParseHistogram::record_change() {
1275   if( PrintParseStatistics && !_parser->is_osr_parse() ) {
1276     ++_bytecodes_parsed[_initial_bytecode];
1277     _nodes_constructed [_initial_bytecode] += (_compiler->unique() - _initial_node_count);
1278     _nodes_transformed [_initial_bytecode] += (current_count(BPH_transforms) - _initial_transforms);
1279     _new_values        [_initial_bytecode] += (current_count(BPH_values)     - _initial_values);
1280   }
1281 }
1282 
1283 
1284 //----------------------------print--------------------------------------------
1285 void Parse::BytecodeParseHistogram::print(float cutoff) {
1286   ResourceMark rm;
1287   // print profile
1288   int total  = 0;
1289   int i      = 0;
1290   for( i = 0; i < Bytecodes::number_of_codes; ++i ) { total += _bytecodes_parsed[i]; }
1291   int abs_sum = 0;
1292   tty->cr();   //0123456789012345678901234567890123456789012345678901234567890123456789
1293   tty->print_cr("Histogram of %d parsed bytecodes:", total);
1294   if( total == 0 ) { return; }
1295   tty->cr();
1296   tty->print_cr("absolute:  count of compiled bytecodes of this type");
1297   tty->print_cr("relative:  percentage contribution to compiled nodes");
1298   tty->print_cr("nodes   :  Average number of nodes constructed per bytecode");
1299   tty->print_cr("rnodes  :  Significance towards total nodes constructed, (nodes*relative)");
1300   tty->print_cr("transforms: Average amount of tranform progress per bytecode compiled");
1301   tty->print_cr("values  :  Average number of node values improved per bytecode");
1302   tty->print_cr("name    :  Bytecode name");
1303   tty->cr();
1304   tty->print_cr("  absolute  relative   nodes  rnodes  transforms  values   name");
1305   tty->print_cr("----------------------------------------------------------------------");
1306   while (--i > 0) {
1307     int       abs = _bytecodes_parsed[i];
1308     float     rel = abs * 100.0F / total;
1309     float   nodes = _bytecodes_parsed[i] == 0 ? 0 : (1.0F * _nodes_constructed[i])/_bytecodes_parsed[i];
1310     float  rnodes = _bytecodes_parsed[i] == 0 ? 0 :  rel * nodes;
1311     float  xforms = _bytecodes_parsed[i] == 0 ? 0 : (1.0F * _nodes_transformed[i])/_bytecodes_parsed[i];
1312     float  values = _bytecodes_parsed[i] == 0 ? 0 : (1.0F * _new_values       [i])/_bytecodes_parsed[i];
1313     if (cutoff <= rel) {
1314       tty->print_cr("%10d  %7.2f%%  %6.1f  %6.2f   %6.1f   %6.1f     %s", abs, rel, nodes, rnodes, xforms, values, name_for_bc(i));
1315       abs_sum += abs;
1316     }
1317   }
1318   tty->print_cr("----------------------------------------------------------------------");
1319   float rel_sum = abs_sum * 100.0F / total;
1320   tty->print_cr("%10d  %7.2f%%    (cutoff = %.2f%%)", abs_sum, rel_sum, cutoff);
1321   tty->print_cr("----------------------------------------------------------------------");
1322   tty->cr();
1323 }
1324 #endif
1325 
1326 //----------------------------load_state_from----------------------------------
1327 // Load block/map/sp.  But not do not touch iter/bci.
1328 void Parse::load_state_from(Block* block) {
1329   set_block(block);
1330   // load the block's JVM state:
1331   set_map(block->start_map());
1332   set_sp( block->start_sp());
1333 }
1334 
1335 
1336 //-----------------------------record_state------------------------------------
1337 void Parse::Block::record_state(Parse* p) {
1338   assert(!is_merged(), "can only record state once, on 1st inflow");
1339   assert(start_sp() == p->sp(), "stack pointer must agree with ciTypeFlow");
1340   set_start_map(p->stop());
1341 }
1342 
1343 
1344 //------------------------------do_one_block-----------------------------------
1345 void Parse::do_one_block() {
1346   if (TraceOptoParse) {
1347     Block *b = block();
1348     int ns = b->num_successors();
1349     int nt = b->all_successors();
1350 
1351     tty->print("Parsing block #%d at bci [%d,%d), successors: ",
1352                   block()->rpo(), block()->start(), block()->limit());
1353     for (int i = 0; i < nt; i++) {
1354       tty->print((( i < ns) ? " %d" : " %d(e)"), b->successor_at(i)->rpo());
1355     }
1356     if (b->is_loop_head()) tty->print("  lphd");
1357     tty->print_cr("");
1358   }
1359 
1360   assert(block()->is_merged(), "must be merged before being parsed");
1361   block()->mark_parsed();
1362   ++_blocks_parsed;
1363 
1364   // Set iterator to start of block.
1365   iter().reset_to_bci(block()->start());
1366 
1367   CompileLog* log = C->log();
1368 
1369   // Parse bytecodes
1370   while (!stopped() && !failing()) {
1371     iter().next();
1372 
1373     // Learn the current bci from the iterator:
1374     set_parse_bci(iter().cur_bci());
1375 
1376     if (bci() == block()->limit()) {
1377       // Do not walk into the next block until directed by do_all_blocks.
1378       merge(bci());
1379       break;
1380     }
1381     assert(bci() < block()->limit(), "bci still in block");
1382 
1383     if (log != NULL) {
1384       // Output an optional context marker, to help place actions
1385       // that occur during parsing of this BC.  If there is no log
1386       // output until the next context string, this context string
1387       // will be silently ignored.
1388       log->set_context("bc code='%d' bci='%d'", (int)bc(), bci());
1389     }
1390 
1391     if (block()->has_trap_at(bci())) {
1392       // We must respect the flow pass's traps, because it will refuse
1393       // to produce successors for trapping blocks.
1394       int trap_index = block()->flow()->trap_index();
1395       assert(trap_index != 0, "trap index must be valid");
1396       uncommon_trap(trap_index);
1397       break;
1398     }
1399 
1400     NOT_PRODUCT( parse_histogram()->set_initial_state(bc()); );
1401 
1402 #ifdef ASSERT
1403     int pre_bc_sp = sp();
1404     int inputs, depth;
1405     bool have_se = !stopped() && compute_stack_effects(inputs, depth);
1406     assert(!have_se || pre_bc_sp >= inputs, err_msg_res("have enough stack to execute this BC: pre_bc_sp=%d, inputs=%d", pre_bc_sp, inputs));
1407 #endif //ASSERT
1408 
1409     do_one_bytecode();
1410 
1411     assert(!have_se || stopped() || failing() || (sp() - pre_bc_sp) == depth,
1412            err_msg_res("incorrect depth prediction: sp=%d, pre_bc_sp=%d, depth=%d", sp(), pre_bc_sp, depth));
1413 
1414     do_exceptions();
1415 
1416     NOT_PRODUCT( parse_histogram()->record_change(); );
1417 
1418     if (log != NULL)
1419       log->clear_context();  // skip marker if nothing was printed
1420 
1421     // Fall into next bytecode.  Each bytecode normally has 1 sequential
1422     // successor which is typically made ready by visiting this bytecode.
1423     // If the successor has several predecessors, then it is a merge
1424     // point, starts a new basic block, and is handled like other basic blocks.
1425   }
1426 }
1427 
1428 
1429 //------------------------------merge------------------------------------------
1430 void Parse::set_parse_bci(int bci) {
1431   set_bci(bci);
1432   Node_Notes* nn = C->default_node_notes();
1433   if (nn == NULL)  return;
1434 
1435   // Collect debug info for inlined calls unless -XX:-DebugInlinedCalls.
1436   if (!DebugInlinedCalls && depth() > 1) {
1437     return;
1438   }
1439 
1440   // Update the JVMS annotation, if present.
1441   JVMState* jvms = nn->jvms();
1442   if (jvms != NULL && jvms->bci() != bci) {
1443     // Update the JVMS.
1444     jvms = jvms->clone_shallow(C);
1445     jvms->set_bci(bci);
1446     nn->set_jvms(jvms);
1447   }
1448 }
1449 
1450 //------------------------------merge------------------------------------------
1451 // Merge the current mapping into the basic block starting at bci
1452 void Parse::merge(int target_bci) {
1453   Block* target = successor_for_bci(target_bci);
1454   if (target == NULL) { handle_missing_successor(target_bci); return; }
1455   assert(!target->is_ready(), "our arrival must be expected");
1456   int pnum = target->next_path_num();
1457   merge_common(target, pnum);
1458 }
1459 
1460 //-------------------------merge_new_path--------------------------------------
1461 // Merge the current mapping into the basic block, using a new path
1462 void Parse::merge_new_path(int target_bci) {
1463   Block* target = successor_for_bci(target_bci);
1464   if (target == NULL) { handle_missing_successor(target_bci); return; }
1465   assert(!target->is_ready(), "new path into frozen graph");
1466   int pnum = target->add_new_path();
1467   merge_common(target, pnum);
1468 }
1469 
1470 //-------------------------merge_exception-------------------------------------
1471 // Merge the current mapping into the basic block starting at bci
1472 // The ex_oop must be pushed on the stack, unlike throw_to_exit.
1473 void Parse::merge_exception(int target_bci) {
1474   assert(sp() == 1, "must have only the throw exception on the stack");
1475   Block* target = successor_for_bci(target_bci);
1476   if (target == NULL) { handle_missing_successor(target_bci); return; }
1477   assert(target->is_handler(), "exceptions are handled by special blocks");
1478   int pnum = target->add_new_path();
1479   merge_common(target, pnum);
1480 }
1481 
1482 //--------------------handle_missing_successor---------------------------------
1483 void Parse::handle_missing_successor(int target_bci) {
1484 #ifndef PRODUCT
1485   Block* b = block();
1486   int trap_bci = b->flow()->has_trap()? b->flow()->trap_bci(): -1;
1487   tty->print_cr("### Missing successor at bci:%d for block #%d (trap_bci:%d)", target_bci, b->rpo(), trap_bci);
1488 #endif
1489   ShouldNotReachHere();
1490 }
1491 
1492 //--------------------------merge_common---------------------------------------
1493 void Parse::merge_common(Parse::Block* target, int pnum) {
1494   if (TraceOptoParse) {
1495     tty->print("Merging state at block #%d bci:%d", target->rpo(), target->start());
1496   }
1497 
1498   // Zap extra stack slots to top
1499   assert(sp() == target->start_sp(), "");
1500   clean_stack(sp());
1501 
1502   if (!target->is_merged()) {   // No prior mapping at this bci
1503     if (TraceOptoParse) { tty->print(" with empty state");  }
1504 
1505     // If this path is dead, do not bother capturing it as a merge.
1506     // It is "as if" we had 1 fewer predecessors from the beginning.
1507     if (stopped()) {
1508       if (TraceOptoParse)  tty->print_cr(", but path is dead and doesn't count");
1509       return;
1510     }
1511 
1512     // Record that a new block has been merged.
1513     ++_blocks_merged;
1514 
1515     // Make a region if we know there are multiple or unpredictable inputs.
1516     // (Also, if this is a plain fall-through, we might see another region,
1517     // which must not be allowed into this block's map.)
1518     if (pnum > PhiNode::Input         // Known multiple inputs.
1519         || target->is_handler()       // These have unpredictable inputs.
1520         || target->is_loop_head()     // Known multiple inputs
1521         || control()->is_Region()) {  // We must hide this guy.
1522 
1523       int current_bci = bci();
1524       set_parse_bci(target->start()); // Set target bci
1525       if (target->is_SEL_head()) {
1526         DEBUG_ONLY( target->mark_merged_backedge(block()); )
1527         if (target->start() == 0) {
1528           // Add loop predicate for the special case when
1529           // there are backbranches to the method entry.
1530           add_predicate();
1531         }
1532       }
1533       // Add a Region to start the new basic block.  Phis will be added
1534       // later lazily.
1535       int edges = target->pred_count();
1536       if (edges < pnum)  edges = pnum;  // might be a new path!
1537       RegionNode *r = new (C) RegionNode(edges+1);
1538       gvn().set_type(r, Type::CONTROL);
1539       record_for_igvn(r);
1540       // zap all inputs to NULL for debugging (done in Node(uint) constructor)
1541       // for (int j = 1; j < edges+1; j++) { r->init_req(j, NULL); }
1542       r->init_req(pnum, control());
1543       set_control(r);
1544       set_parse_bci(current_bci); // Restore bci
1545     }
1546 
1547     // Convert the existing Parser mapping into a mapping at this bci.
1548     store_state_to(target);
1549     assert(target->is_merged(), "do not come here twice");
1550 
1551   } else {                      // Prior mapping at this bci
1552     if (TraceOptoParse) {  tty->print(" with previous state"); }
1553 #ifdef ASSERT
1554     if (target->is_SEL_head()) {
1555       target->mark_merged_backedge(block());
1556     }
1557 #endif
1558     // We must not manufacture more phis if the target is already parsed.
1559     bool nophi = target->is_parsed();
1560 
1561     SafePointNode* newin = map();// Hang on to incoming mapping
1562     Block* save_block = block(); // Hang on to incoming block;
1563     load_state_from(target);    // Get prior mapping
1564 
1565     assert(newin->jvms()->locoff() == jvms()->locoff(), "JVMS layouts agree");
1566     assert(newin->jvms()->stkoff() == jvms()->stkoff(), "JVMS layouts agree");
1567     assert(newin->jvms()->monoff() == jvms()->monoff(), "JVMS layouts agree");
1568     assert(newin->jvms()->endoff() == jvms()->endoff(), "JVMS layouts agree");
1569 
1570     // Iterate over my current mapping and the old mapping.
1571     // Where different, insert Phi functions.
1572     // Use any existing Phi functions.
1573     assert(control()->is_Region(), "must be merging to a region");
1574     RegionNode* r = control()->as_Region();
1575 
1576     // Compute where to merge into
1577     // Merge incoming control path
1578     r->init_req(pnum, newin->control());
1579 
1580     if (pnum == 1) {            // Last merge for this Region?
1581       if (!block()->flow()->is_irreducible_entry()) {
1582         Node* result = _gvn.transform_no_reclaim(r);
1583         if (r != result && TraceOptoParse) {
1584           tty->print_cr("Block #%d replace %d with %d", block()->rpo(), r->_idx, result->_idx);
1585         }
1586       }
1587       record_for_igvn(r);
1588     }
1589 
1590     // Update all the non-control inputs to map:
1591     assert(TypeFunc::Parms == newin->jvms()->locoff(), "parser map should contain only youngest jvms");
1592     bool check_elide_phi = target->is_SEL_backedge(save_block);
1593     for (uint j = 1; j < newin->req(); j++) {
1594       Node* m = map()->in(j);   // Current state of target.
1595       Node* n = newin->in(j);   // Incoming change to target state.
1596       PhiNode* phi;
1597       if (m->is_Phi() && m->as_Phi()->region() == r)
1598         phi = m->as_Phi();
1599       else
1600         phi = NULL;
1601       if (m != n) {             // Different; must merge
1602         switch (j) {
1603         // Frame pointer and Return Address never changes
1604         case TypeFunc::FramePtr:// Drop m, use the original value
1605         case TypeFunc::ReturnAdr:
1606           break;
1607         case TypeFunc::Memory:  // Merge inputs to the MergeMem node
1608           assert(phi == NULL, "the merge contains phis, not vice versa");
1609           merge_memory_edges(n->as_MergeMem(), pnum, nophi);
1610           continue;
1611         default:                // All normal stuff
1612           if (phi == NULL) {
1613             const JVMState* jvms = map()->jvms();
1614             if (EliminateNestedLocks &&
1615                 jvms->is_mon(j) && jvms->is_monitor_box(j)) {
1616               // BoxLock nodes are not commoning.
1617               // Use old BoxLock node as merged box.
1618               assert(newin->jvms()->is_monitor_box(j), "sanity");
1619               // This assert also tests that nodes are BoxLock.
1620               assert(BoxLockNode::same_slot(n, m), "sanity");
1621               C->gvn_replace_by(n, m);
1622             } else if (!check_elide_phi || !target->can_elide_SEL_phi(j)) {
1623               phi = ensure_phi(j, nophi);
1624             }
1625           }
1626           break;
1627         }
1628       }
1629       // At this point, n might be top if:
1630       //  - there is no phi (because TypeFlow detected a conflict), or
1631       //  - the corresponding control edges is top (a dead incoming path)
1632       // It is a bug if we create a phi which sees a garbage value on a live path.
1633 
1634       if (phi != NULL) {
1635         assert(n != top() || r->in(pnum) == top(), "live value must not be garbage");
1636         assert(phi->region() == r, "");
1637         phi->set_req(pnum, n);  // Then add 'n' to the merge
1638         if (pnum == PhiNode::Input) {
1639           // Last merge for this Phi.
1640           // So far, Phis have had a reasonable type from ciTypeFlow.
1641           // Now _gvn will join that with the meet of current inputs.
1642           // BOTTOM is never permissible here, 'cause pessimistically
1643           // Phis of pointers cannot lose the basic pointer type.
1644           debug_only(const Type* bt1 = phi->bottom_type());
1645           assert(bt1 != Type::BOTTOM, "should not be building conflict phis");
1646           map()->set_req(j, _gvn.transform_no_reclaim(phi));
1647           debug_only(const Type* bt2 = phi->bottom_type());
1648           assert(bt2->higher_equal(bt1), "must be consistent with type-flow");
1649           record_for_igvn(phi);
1650         }
1651       }
1652     } // End of for all values to be merged
1653 
1654     if (pnum == PhiNode::Input &&
1655         !r->in(0)) {         // The occasional useless Region
1656       assert(control() == r, "");
1657       set_control(r->nonnull_req());
1658     }
1659 
1660     // newin has been subsumed into the lazy merge, and is now dead.
1661     set_block(save_block);
1662 
1663     stop();                     // done with this guy, for now
1664   }
1665 
1666   if (TraceOptoParse) {
1667     tty->print_cr(" on path %d", pnum);
1668   }
1669 
1670   // Done with this parser state.
1671   assert(stopped(), "");
1672 }
1673 
1674 
1675 //--------------------------merge_memory_edges---------------------------------
1676 void Parse::merge_memory_edges(MergeMemNode* n, int pnum, bool nophi) {
1677   // (nophi means we must not create phis, because we already parsed here)
1678   assert(n != NULL, "");
1679   // Merge the inputs to the MergeMems
1680   MergeMemNode* m = merged_memory();
1681 
1682   assert(control()->is_Region(), "must be merging to a region");
1683   RegionNode* r = control()->as_Region();
1684 
1685   PhiNode* base = NULL;
1686   MergeMemNode* remerge = NULL;
1687   for (MergeMemStream mms(m, n); mms.next_non_empty2(); ) {
1688     Node *p = mms.force_memory();
1689     Node *q = mms.memory2();
1690     if (mms.is_empty() && nophi) {
1691       // Trouble:  No new splits allowed after a loop body is parsed.
1692       // Instead, wire the new split into a MergeMem on the backedge.
1693       // The optimizer will sort it out, slicing the phi.
1694       if (remerge == NULL) {
1695         assert(base != NULL, "");
1696         assert(base->in(0) != NULL, "should not be xformed away");
1697         remerge = MergeMemNode::make(C, base->in(pnum));
1698         gvn().set_type(remerge, Type::MEMORY);
1699         base->set_req(pnum, remerge);
1700       }
1701       remerge->set_memory_at(mms.alias_idx(), q);
1702       continue;
1703     }
1704     assert(!q->is_MergeMem(), "");
1705     PhiNode* phi;
1706     if (p != q) {
1707       phi = ensure_memory_phi(mms.alias_idx(), nophi);
1708     } else {
1709       if (p->is_Phi() && p->as_Phi()->region() == r)
1710         phi = p->as_Phi();
1711       else
1712         phi = NULL;
1713     }
1714     // Insert q into local phi
1715     if (phi != NULL) {
1716       assert(phi->region() == r, "");
1717       p = phi;
1718       phi->set_req(pnum, q);
1719       if (mms.at_base_memory()) {
1720         base = phi;  // delay transforming it
1721       } else if (pnum == 1) {
1722         record_for_igvn(phi);
1723         p = _gvn.transform_no_reclaim(phi);
1724       }
1725       mms.set_memory(p);// store back through the iterator
1726     }
1727   }
1728   // Transform base last, in case we must fiddle with remerging.
1729   if (base != NULL && pnum == 1) {
1730     record_for_igvn(base);
1731     m->set_base_memory( _gvn.transform_no_reclaim(base) );
1732   }
1733 }
1734 
1735 
1736 //------------------------ensure_phis_everywhere-------------------------------
1737 void Parse::ensure_phis_everywhere() {
1738   ensure_phi(TypeFunc::I_O);
1739 
1740   // Ensure a phi on all currently known memories.
1741   for (MergeMemStream mms(merged_memory()); mms.next_non_empty(); ) {
1742     ensure_memory_phi(mms.alias_idx());
1743     debug_only(mms.set_memory());  // keep the iterator happy
1744   }
1745 
1746   // Note:  This is our only chance to create phis for memory slices.
1747   // If we miss a slice that crops up later, it will have to be
1748   // merged into the base-memory phi that we are building here.
1749   // Later, the optimizer will comb out the knot, and build separate
1750   // phi-loops for each memory slice that matters.
1751 
1752   // Monitors must nest nicely and not get confused amongst themselves.
1753   // Phi-ify everything up to the monitors, though.
1754   uint monoff = map()->jvms()->monoff();
1755   uint nof_monitors = map()->jvms()->nof_monitors();
1756 
1757   assert(TypeFunc::Parms == map()->jvms()->locoff(), "parser map should contain only youngest jvms");
1758   bool check_elide_phi = block()->is_SEL_head();
1759   for (uint i = TypeFunc::Parms; i < monoff; i++) {
1760     if (!check_elide_phi || !block()->can_elide_SEL_phi(i)) {
1761       ensure_phi(i);
1762     }
1763   }
1764 
1765   // Even monitors need Phis, though they are well-structured.
1766   // This is true for OSR methods, and also for the rare cases where
1767   // a monitor object is the subject of a replace_in_map operation.
1768   // See bugs 4426707 and 5043395.
1769   for (uint m = 0; m < nof_monitors; m++) {
1770     ensure_phi(map()->jvms()->monitor_obj_offset(m));
1771   }
1772 }
1773 
1774 
1775 //-----------------------------add_new_path------------------------------------
1776 // Add a previously unaccounted predecessor to this block.
1777 int Parse::Block::add_new_path() {
1778   // If there is no map, return the lowest unused path number.
1779   if (!is_merged())  return pred_count()+1;  // there will be a map shortly
1780 
1781   SafePointNode* map = start_map();
1782   if (!map->control()->is_Region())
1783     return pred_count()+1;  // there may be a region some day
1784   RegionNode* r = map->control()->as_Region();
1785 
1786   // Add new path to the region.
1787   uint pnum = r->req();
1788   r->add_req(NULL);
1789 
1790   for (uint i = 1; i < map->req(); i++) {
1791     Node* n = map->in(i);
1792     if (i == TypeFunc::Memory) {
1793       // Ensure a phi on all currently known memories.
1794       for (MergeMemStream mms(n->as_MergeMem()); mms.next_non_empty(); ) {
1795         Node* phi = mms.memory();
1796         if (phi->is_Phi() && phi->as_Phi()->region() == r) {
1797           assert(phi->req() == pnum, "must be same size as region");
1798           phi->add_req(NULL);
1799         }
1800       }
1801     } else {
1802       if (n->is_Phi() && n->as_Phi()->region() == r) {
1803         assert(n->req() == pnum, "must be same size as region");
1804         n->add_req(NULL);
1805       }
1806     }
1807   }
1808 
1809   return pnum;
1810 }
1811 
1812 //------------------------------ensure_phi-------------------------------------
1813 // Turn the idx'th entry of the current map into a Phi
1814 PhiNode *Parse::ensure_phi(int idx, bool nocreate) {
1815   SafePointNode* map = this->map();
1816   Node* region = map->control();
1817   assert(region->is_Region(), "");
1818 
1819   Node* o = map->in(idx);
1820   assert(o != NULL, "");
1821 
1822   if (o == top())  return NULL; // TOP always merges into TOP
1823 
1824   if (o->is_Phi() && o->as_Phi()->region() == region) {
1825     return o->as_Phi();
1826   }
1827 
1828   // Now use a Phi here for merging
1829   assert(!nocreate, "Cannot build a phi for a block already parsed.");
1830   const JVMState* jvms = map->jvms();
1831   const Type* t;
1832   if (jvms->is_loc(idx)) {
1833     t = block()->local_type_at(idx - jvms->locoff());
1834   } else if (jvms->is_stk(idx)) {
1835     t = block()->stack_type_at(idx - jvms->stkoff());
1836   } else if (jvms->is_mon(idx)) {
1837     assert(!jvms->is_monitor_box(idx), "no phis for boxes");
1838     t = TypeInstPtr::BOTTOM; // this is sufficient for a lock object
1839   } else if ((uint)idx < TypeFunc::Parms) {
1840     t = o->bottom_type();  // Type::RETURN_ADDRESS or such-like.
1841   } else {
1842     assert(false, "no type information for this phi");
1843   }
1844 
1845   // If the type falls to bottom, then this must be a local that
1846   // is mixing ints and oops or some such.  Forcing it to top
1847   // makes it go dead.
1848   if (t == Type::BOTTOM) {
1849     map->set_req(idx, top());
1850     return NULL;
1851   }
1852 
1853   // Do not create phis for top either.
1854   // A top on a non-null control flow must be an unused even after the.phi.
1855   if (t == Type::TOP || t == Type::HALF) {
1856     map->set_req(idx, top());
1857     return NULL;
1858   }
1859 
1860   PhiNode* phi = PhiNode::make(region, o, t);
1861   gvn().set_type(phi, t);
1862   if (C->do_escape_analysis()) record_for_igvn(phi);
1863   map->set_req(idx, phi);
1864   return phi;
1865 }
1866 
1867 //--------------------------ensure_memory_phi----------------------------------
1868 // Turn the idx'th slice of the current memory into a Phi
1869 PhiNode *Parse::ensure_memory_phi(int idx, bool nocreate) {
1870   MergeMemNode* mem = merged_memory();
1871   Node* region = control();
1872   assert(region->is_Region(), "");
1873 
1874   Node *o = (idx == Compile::AliasIdxBot)? mem->base_memory(): mem->memory_at(idx);
1875   assert(o != NULL && o != top(), "");
1876 
1877   PhiNode* phi;
1878   if (o->is_Phi() && o->as_Phi()->region() == region) {
1879     phi = o->as_Phi();
1880     if (phi == mem->base_memory() && idx >= Compile::AliasIdxRaw) {
1881       // clone the shared base memory phi to make a new memory split
1882       assert(!nocreate, "Cannot build a phi for a block already parsed.");
1883       const Type* t = phi->bottom_type();
1884       const TypePtr* adr_type = C->get_adr_type(idx);
1885       phi = phi->slice_memory(adr_type);
1886       gvn().set_type(phi, t);
1887     }
1888     return phi;
1889   }
1890 
1891   // Now use a Phi here for merging
1892   assert(!nocreate, "Cannot build a phi for a block already parsed.");
1893   const Type* t = o->bottom_type();
1894   const TypePtr* adr_type = C->get_adr_type(idx);
1895   phi = PhiNode::make(region, o, t, adr_type);
1896   gvn().set_type(phi, t);
1897   if (idx == Compile::AliasIdxBot)
1898     mem->set_base_memory(phi);
1899   else
1900     mem->set_memory_at(idx, phi);
1901   return phi;
1902 }
1903 
1904 //------------------------------call_register_finalizer-----------------------
1905 // Check the klass of the receiver and call register_finalizer if the
1906 // class need finalization.
1907 void Parse::call_register_finalizer() {
1908   Node* receiver = local(0);
1909   assert(receiver != NULL && receiver->bottom_type()->isa_instptr() != NULL,
1910          "must have non-null instance type");
1911 
1912   const TypeInstPtr *tinst = receiver->bottom_type()->isa_instptr();
1913   if (tinst != NULL && tinst->klass()->is_loaded() && !tinst->klass_is_exact()) {
1914     // The type isn't known exactly so see if CHA tells us anything.
1915     ciInstanceKlass* ik = tinst->klass()->as_instance_klass();
1916     if (!Dependencies::has_finalizable_subclass(ik)) {
1917       // No finalizable subclasses so skip the dynamic check.
1918       C->dependencies()->assert_has_no_finalizable_subclasses(ik);
1919       return;
1920     }
1921   }
1922 
1923   // Insert a dynamic test for whether the instance needs
1924   // finalization.  In general this will fold up since the concrete
1925   // class is often visible so the access flags are constant.
1926   Node* klass_addr = basic_plus_adr( receiver, receiver, oopDesc::klass_offset_in_bytes() );
1927   Node* klass = _gvn.transform( LoadKlassNode::make(_gvn, immutable_memory(), klass_addr, TypeInstPtr::KLASS) );
1928 
1929   Node* access_flags_addr = basic_plus_adr(klass, klass, in_bytes(Klass::access_flags_offset()));
1930   Node* access_flags = make_load(NULL, access_flags_addr, TypeInt::INT, T_INT);
1931 
1932   Node* mask  = _gvn.transform(new (C) AndINode(access_flags, intcon(JVM_ACC_HAS_FINALIZER)));
1933   Node* check = _gvn.transform(new (C) CmpINode(mask, intcon(0)));
1934   Node* test  = _gvn.transform(new (C) BoolNode(check, BoolTest::ne));
1935 
1936   IfNode* iff = create_and_map_if(control(), test, PROB_MAX, COUNT_UNKNOWN);
1937 
1938   RegionNode* result_rgn = new (C) RegionNode(3);
1939   record_for_igvn(result_rgn);
1940 
1941   Node *skip_register = _gvn.transform(new (C) IfFalseNode(iff));
1942   result_rgn->init_req(1, skip_register);
1943 
1944   Node *needs_register = _gvn.transform(new (C) IfTrueNode(iff));
1945   set_control(needs_register);
1946   if (stopped()) {
1947     // There is no slow path.
1948     result_rgn->init_req(2, top());
1949   } else {
1950     Node *call = make_runtime_call(RC_NO_LEAF,
1951                                    OptoRuntime::register_finalizer_Type(),
1952                                    OptoRuntime::register_finalizer_Java(),
1953                                    NULL, TypePtr::BOTTOM,
1954                                    receiver);
1955     make_slow_call_ex(call, env()->Throwable_klass(), true);
1956 
1957     Node* fast_io  = call->in(TypeFunc::I_O);
1958     Node* fast_mem = call->in(TypeFunc::Memory);
1959     // These two phis are pre-filled with copies of of the fast IO and Memory
1960     Node* io_phi   = PhiNode::make(result_rgn, fast_io,  Type::ABIO);
1961     Node* mem_phi  = PhiNode::make(result_rgn, fast_mem, Type::MEMORY, TypePtr::BOTTOM);
1962 
1963     result_rgn->init_req(2, control());
1964     io_phi    ->init_req(2, i_o());
1965     mem_phi   ->init_req(2, reset_memory());
1966 
1967     set_all_memory( _gvn.transform(mem_phi) );
1968     set_i_o(        _gvn.transform(io_phi) );
1969   }
1970 
1971   set_control( _gvn.transform(result_rgn) );
1972 }
1973 
1974 //------------------------------return_current---------------------------------
1975 // Append current _map to _exit_return
1976 void Parse::return_current(Node* value) {
1977   if (RegisterFinalizersAtInit &&
1978       method()->intrinsic_id() == vmIntrinsics::_Object_init) {
1979     call_register_finalizer();
1980   }
1981 
1982   // Do not set_parse_bci, so that return goo is credited to the return insn.
1983   set_bci(InvocationEntryBci);
1984   if (method()->is_synchronized() && GenerateSynchronizationCode) {
1985     shared_unlock(_synch_lock->box_node(), _synch_lock->obj_node());
1986   }
1987   if (C->env()->dtrace_method_probes()) {
1988     make_dtrace_method_exit(method());
1989   }
1990   SafePointNode* exit_return = _exits.map();
1991   exit_return->in( TypeFunc::Control  )->add_req( control() );
1992   exit_return->in( TypeFunc::I_O      )->add_req( i_o    () );
1993   Node *mem = exit_return->in( TypeFunc::Memory   );
1994   for (MergeMemStream mms(mem->as_MergeMem(), merged_memory()); mms.next_non_empty2(); ) {
1995     if (mms.is_empty()) {
1996       // get a copy of the base memory, and patch just this one input
1997       const TypePtr* adr_type = mms.adr_type(C);
1998       Node* phi = mms.force_memory()->as_Phi()->slice_memory(adr_type);
1999       assert(phi->as_Phi()->region() == mms.base_memory()->in(0), "");
2000       gvn().set_type_bottom(phi);
2001       phi->del_req(phi->req()-1);  // prepare to re-patch
2002       mms.set_memory(phi);
2003     }
2004     mms.memory()->add_req(mms.memory2());
2005   }
2006 
2007   // frame pointer is always same, already captured
2008   if (value != NULL) {
2009     // If returning oops to an interface-return, there is a silent free
2010     // cast from oop to interface allowed by the Verifier.  Make it explicit
2011     // here.
2012     Node* phi = _exits.argument(0);
2013     const TypeInstPtr *tr = phi->bottom_type()->isa_instptr();
2014     if( tr && tr->klass()->is_loaded() &&
2015         tr->klass()->is_interface() ) {
2016       const TypeInstPtr *tp = value->bottom_type()->isa_instptr();
2017       if (tp && tp->klass()->is_loaded() &&
2018           !tp->klass()->is_interface()) {
2019         // sharpen the type eagerly; this eases certain assert checking
2020         if (tp->higher_equal(TypeInstPtr::NOTNULL))
2021           tr = tr->join(TypeInstPtr::NOTNULL)->is_instptr();
2022         value = _gvn.transform(new (C) CheckCastPPNode(0,value,tr));
2023       }
2024     }
2025     phi->add_req(value);
2026   }
2027 
2028   stop_and_kill_map();          // This CFG path dies here
2029 }
2030 
2031 
2032 //------------------------------add_safepoint----------------------------------
2033 void Parse::add_safepoint() {
2034   // See if we can avoid this safepoint.  No need for a SafePoint immediately
2035   // after a Call (except Leaf Call) or another SafePoint.
2036   Node *proj = control();
2037   bool add_poll_param = SafePointNode::needs_polling_address_input();
2038   uint parms = add_poll_param ? TypeFunc::Parms+1 : TypeFunc::Parms;
2039   if( proj->is_Proj() ) {
2040     Node *n0 = proj->in(0);
2041     if( n0->is_Catch() ) {
2042       n0 = n0->in(0)->in(0);
2043       assert( n0->is_Call(), "expect a call here" );
2044     }
2045     if( n0->is_Call() ) {
2046       if( n0->as_Call()->guaranteed_safepoint() )
2047         return;
2048     } else if( n0->is_SafePoint() && n0->req() >= parms ) {
2049       return;
2050     }
2051   }
2052 
2053   // Clear out dead values from the debug info.
2054   kill_dead_locals();
2055 
2056   // Clone the JVM State
2057   SafePointNode *sfpnt = new (C) SafePointNode(parms, NULL);
2058 
2059   // Capture memory state BEFORE a SafePoint.  Since we can block at a
2060   // SafePoint we need our GC state to be safe; i.e. we need all our current
2061   // write barriers (card marks) to not float down after the SafePoint so we
2062   // must read raw memory.  Likewise we need all oop stores to match the card
2063   // marks.  If deopt can happen, we need ALL stores (we need the correct JVM
2064   // state on a deopt).
2065 
2066   // We do not need to WRITE the memory state after a SafePoint.  The control
2067   // edge will keep card-marks and oop-stores from floating up from below a
2068   // SafePoint and our true dependency added here will keep them from floating
2069   // down below a SafePoint.
2070 
2071   // Clone the current memory state
2072   Node* mem = MergeMemNode::make(C, map()->memory());
2073 
2074   mem = _gvn.transform(mem);
2075 
2076   // Pass control through the safepoint
2077   sfpnt->init_req(TypeFunc::Control  , control());
2078   // Fix edges normally used by a call
2079   sfpnt->init_req(TypeFunc::I_O      , top() );
2080   sfpnt->init_req(TypeFunc::Memory   , mem   );
2081   sfpnt->init_req(TypeFunc::ReturnAdr, top() );
2082   sfpnt->init_req(TypeFunc::FramePtr , top() );
2083 
2084   // Create a node for the polling address
2085   if( add_poll_param ) {
2086     Node *polladr = ConPNode::make(C, (address)os::get_polling_page());
2087     sfpnt->init_req(TypeFunc::Parms+0, _gvn.transform(polladr));
2088   }
2089 
2090   // Fix up the JVM State edges
2091   add_safepoint_edges(sfpnt);
2092   Node *transformed_sfpnt = _gvn.transform(sfpnt);
2093   set_control(transformed_sfpnt);
2094 
2095   // Provide an edge from root to safepoint.  This makes the safepoint
2096   // appear useful until the parse has completed.
2097   if( OptoRemoveUseless && transformed_sfpnt->is_SafePoint() ) {
2098     assert(C->root() != NULL, "Expect parse is still valid");
2099     C->root()->add_prec(transformed_sfpnt);
2100   }
2101 }
2102 
2103 #ifndef PRODUCT
2104 //------------------------show_parse_info--------------------------------------
2105 void Parse::show_parse_info() {
2106   InlineTree* ilt = NULL;
2107   if (C->ilt() != NULL) {
2108     JVMState* caller_jvms = is_osr_parse() ? caller()->caller() : caller();
2109     ilt = InlineTree::find_subtree_from_root(C->ilt(), caller_jvms, method());
2110   }
2111   if (PrintCompilation && Verbose) {
2112     if (depth() == 1) {
2113       if( ilt->count_inlines() ) {
2114         tty->print("    __inlined %d (%d bytes)", ilt->count_inlines(),
2115                      ilt->count_inline_bcs());
2116         tty->cr();
2117       }
2118     } else {
2119       if (method()->is_synchronized())         tty->print("s");
2120       if (method()->has_exception_handlers())  tty->print("!");
2121       // Check this is not the final compiled version
2122       if (C->trap_can_recompile()) {
2123         tty->print("-");
2124       } else {
2125         tty->print(" ");
2126       }
2127       method()->print_short_name();
2128       if (is_osr_parse()) {
2129         tty->print(" @ %d", osr_bci());
2130       }
2131       tty->print(" (%d bytes)",method()->code_size());
2132       if (ilt->count_inlines()) {
2133         tty->print(" __inlined %d (%d bytes)", ilt->count_inlines(),
2134                    ilt->count_inline_bcs());
2135       }
2136       tty->cr();
2137     }
2138   }
2139   if (PrintOpto && (depth() == 1 || PrintOptoInlining)) {
2140     // Print that we succeeded; suppress this message on the first osr parse.
2141 
2142     if (method()->is_synchronized())         tty->print("s");
2143     if (method()->has_exception_handlers())  tty->print("!");
2144     // Check this is not the final compiled version
2145     if (C->trap_can_recompile() && depth() == 1) {
2146       tty->print("-");
2147     } else {
2148       tty->print(" ");
2149     }
2150     if( depth() != 1 ) { tty->print("   "); }  // missing compile count
2151     for (int i = 1; i < depth(); ++i) { tty->print("  "); }
2152     method()->print_short_name();
2153     if (is_osr_parse()) {
2154       tty->print(" @ %d", osr_bci());
2155     }
2156     if (ilt->caller_bci() != -1) {
2157       tty->print(" @ %d", ilt->caller_bci());
2158     }
2159     tty->print(" (%d bytes)",method()->code_size());
2160     if (ilt->count_inlines()) {
2161       tty->print(" __inlined %d (%d bytes)", ilt->count_inlines(),
2162                  ilt->count_inline_bcs());
2163     }
2164     tty->cr();
2165   }
2166 }
2167 
2168 
2169 //------------------------------dump-------------------------------------------
2170 // Dump information associated with the bytecodes of current _method
2171 void Parse::dump() {
2172   if( method() != NULL ) {
2173     // Iterate over bytecodes
2174     ciBytecodeStream iter(method());
2175     for( Bytecodes::Code bc = iter.next(); bc != ciBytecodeStream::EOBC() ; bc = iter.next() ) {
2176       dump_bci( iter.cur_bci() );
2177       tty->cr();
2178     }
2179   }
2180 }
2181 
2182 // Dump information associated with a byte code index, 'bci'
2183 void Parse::dump_bci(int bci) {
2184   // Output info on merge-points, cloning, and within _jsr..._ret
2185   // NYI
2186   tty->print(" bci:%d", bci);
2187 }
2188 
2189 #endif