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