1 /*
   2  * Copyright (c) 1997, 2023, 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 "memory/resourceArea.hpp"
  29 #include "oops/method.hpp"
  30 #include "opto/addnode.hpp"
  31 #include "opto/c2compiler.hpp"
  32 #include "opto/castnode.hpp"
  33 #include "opto/idealGraphPrinter.hpp"
  34 #include "opto/locknode.hpp"
  35 #include "opto/memnode.hpp"
  36 #include "opto/opaquenode.hpp"
  37 #include "opto/parse.hpp"
  38 #include "opto/rootnode.hpp"
  39 #include "opto/runtime.hpp"
  40 #include "opto/type.hpp"
  41 #include "runtime/handles.inline.hpp"
  42 #include "runtime/safepointMechanism.hpp"
  43 #include "runtime/sharedRuntime.hpp"
  44 #include "utilities/bitMap.inline.hpp"
  45 #include "utilities/copy.hpp"
  46 
  47 // Static array so we can figure out which bytecodes stop us from compiling
  48 // the most. Some of the non-static variables are needed in bytecodeInfo.cpp
  49 // and eventually should be encapsulated in a proper class (gri 8/18/98).
  50 
  51 #ifndef PRODUCT
  52 int nodes_created              = 0;
  53 int methods_parsed             = 0;
  54 int methods_seen               = 0;
  55 int blocks_parsed              = 0;
  56 int blocks_seen                = 0;
  57 
  58 int explicit_null_checks_inserted = 0;
  59 int explicit_null_checks_elided   = 0;
  60 int all_null_checks_found         = 0;
  61 int implicit_null_checks          = 0;
  62 
  63 bool Parse::BytecodeParseHistogram::_initialized = false;
  64 uint Parse::BytecodeParseHistogram::_bytecodes_parsed [Bytecodes::number_of_codes];
  65 uint Parse::BytecodeParseHistogram::_nodes_constructed[Bytecodes::number_of_codes];
  66 uint Parse::BytecodeParseHistogram::_nodes_transformed[Bytecodes::number_of_codes];
  67 uint Parse::BytecodeParseHistogram::_new_values       [Bytecodes::number_of_codes];
  68 
  69 //------------------------------print_statistics-------------------------------
  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   }
  78   tty->print_cr("Blocks parsed: %d  Blocks seen: %d", blocks_parsed, blocks_seen);
  79 
  80   if (explicit_null_checks_inserted) {
  81     tty->print_cr("%d original NULL checks - %d elided (%2d%%); optimizer leaves %d,",
  82                   explicit_null_checks_inserted, explicit_null_checks_elided,
  83                   (100*explicit_null_checks_elided)/explicit_null_checks_inserted,
  84                   all_null_checks_found);
  85   }
  86   if (all_null_checks_found) {
  87     tty->print_cr("%d made implicit (%2d%%)", implicit_null_checks,
  88                   (100*implicit_null_checks)/all_null_checks_found);
  89   }
  90   if (SharedRuntime::_implicit_null_throws) {
  91     tty->print_cr("%d implicit null exceptions at runtime",
  92                   SharedRuntime::_implicit_null_throws);
  93   }
  94 
  95   if (PrintParseStatistics && BytecodeParseHistogram::initialized()) {
  96     BytecodeParseHistogram::print();
  97   }
  98 }
  99 #endif
 100 
 101 //------------------------------ON STACK REPLACEMENT---------------------------
 102 
 103 // Construct a node which can be used to get incoming state for
 104 // on stack replacement.
 105 Node *Parse::fetch_interpreter_state(int index,
 106                                      BasicType bt,
 107                                      Node *local_addrs,
 108                                      Node *local_addrs_base) {
 109   Node *mem = memory(Compile::AliasIdxRaw);
 110   Node *adr = basic_plus_adr( local_addrs_base, local_addrs, -index*wordSize );
 111   Node *ctl = control();
 112 
 113   // Very similar to LoadNode::make, except we handle un-aligned longs and
 114   // doubles on Sparc.  Intel can handle them just fine directly.
 115   Node *l = NULL;
 116   switch (bt) {                // Signature is flattened
 117   case T_INT:     l = new LoadINode(ctl, mem, adr, TypeRawPtr::BOTTOM, TypeInt::INT,        MemNode::unordered); break;
 118   case T_FLOAT:   l = new LoadFNode(ctl, mem, adr, TypeRawPtr::BOTTOM, Type::FLOAT,         MemNode::unordered); break;
 119   case T_ADDRESS: l = new LoadPNode(ctl, mem, adr, TypeRawPtr::BOTTOM, TypeRawPtr::BOTTOM,  MemNode::unordered); break;
 120   case T_OBJECT:  l = new LoadPNode(ctl, mem, adr, TypeRawPtr::BOTTOM, TypeInstPtr::BOTTOM, MemNode::unordered); break;
 121   case T_LONG:
 122   case T_DOUBLE: {
 123     // Since arguments are in reverse order, the argument address 'adr'
 124     // refers to the back half of the long/double.  Recompute adr.
 125     adr = basic_plus_adr(local_addrs_base, local_addrs, -(index+1)*wordSize);
 126     if (Matcher::misaligned_doubles_ok) {
 127       l = (bt == T_DOUBLE)
 128         ? (Node*)new LoadDNode(ctl, mem, adr, TypeRawPtr::BOTTOM, Type::DOUBLE, MemNode::unordered)
 129         : (Node*)new LoadLNode(ctl, mem, adr, TypeRawPtr::BOTTOM, TypeLong::LONG, MemNode::unordered);
 130     } else {
 131       l = (bt == T_DOUBLE)
 132         ? (Node*)new LoadD_unalignedNode(ctl, mem, adr, TypeRawPtr::BOTTOM, MemNode::unordered)
 133         : (Node*)new LoadL_unalignedNode(ctl, mem, adr, TypeRawPtr::BOTTOM, MemNode::unordered);
 134     }
 135     break;
 136   }
 137   default: ShouldNotReachHere();
 138   }
 139   return _gvn.transform(l);
 140 }
 141 
 142 // Helper routine to prevent the interpreter from handing
 143 // unexpected typestate to an OSR method.
 144 // The Node l is a value newly dug out of the interpreter frame.
 145 // The type is the type predicted by ciTypeFlow.  Note that it is
 146 // not a general type, but can only come from Type::get_typeflow_type.
 147 // The safepoint is a map which will feed an uncommon trap.
 148 Node* Parse::check_interpreter_type(Node* l, const Type* type,
 149                                     SafePointNode* &bad_type_exit) {
 150 
 151   const TypeOopPtr* tp = type->isa_oopptr();
 152 
 153   // TypeFlow may assert null-ness if a type appears unloaded.
 154   if (type == TypePtr::NULL_PTR ||
 155       (tp != NULL && !tp->is_loaded())) {
 156     // Value must be null, not a real oop.
 157     Node* chk = _gvn.transform( new CmpPNode(l, null()) );
 158     Node* tst = _gvn.transform( new BoolNode(chk, BoolTest::eq) );
 159     IfNode* iff = create_and_map_if(control(), tst, PROB_MAX, COUNT_UNKNOWN);
 160     set_control(_gvn.transform( new IfTrueNode(iff) ));
 161     Node* bad_type = _gvn.transform( new IfFalseNode(iff) );
 162     bad_type_exit->control()->add_req(bad_type);
 163     l = null();
 164   }
 165 
 166   // Typeflow can also cut off paths from the CFG, based on
 167   // types which appear unloaded, or call sites which appear unlinked.
 168   // When paths are cut off, values at later merge points can rise
 169   // toward more specific classes.  Make sure these specific classes
 170   // are still in effect.
 171   if (tp != NULL && !tp->is_same_java_type_as(TypeInstPtr::BOTTOM)) {
 172     // TypeFlow asserted a specific object type.  Value must have that type.
 173     Node* bad_type_ctrl = NULL;
 174     l = gen_checkcast(l, makecon(tp->as_klass_type()->cast_to_exactness(true)), &bad_type_ctrl);
 175     bad_type_exit->control()->add_req(bad_type_ctrl);
 176   }
 177 
 178   assert(_gvn.type(l)->higher_equal(type), "must constrain OSR typestate");
 179   return l;
 180 }
 181 
 182 // Helper routine which sets up elements of the initial parser map when
 183 // performing a parse for on stack replacement.  Add values into map.
 184 // The only parameter contains the address of a interpreter arguments.
 185 void Parse::load_interpreter_state(Node* osr_buf) {
 186   int index;
 187   int max_locals = jvms()->loc_size();
 188   int max_stack  = jvms()->stk_size();
 189 
 190 
 191   // Mismatch between method and jvms can occur since map briefly held
 192   // an OSR entry state (which takes up one RawPtr word).
 193   assert(max_locals == method()->max_locals(), "sanity");
 194   assert(max_stack  >= method()->max_stack(),  "sanity");
 195   assert((int)jvms()->endoff() == TypeFunc::Parms + max_locals + max_stack, "sanity");
 196   assert((int)jvms()->endoff() == (int)map()->req(), "sanity");
 197 
 198   // Find the start block.
 199   Block* osr_block = start_block();
 200   assert(osr_block->start() == osr_bci(), "sanity");
 201 
 202   // Set initial BCI.
 203   set_parse_bci(osr_block->start());
 204 
 205   // Set initial stack depth.
 206   set_sp(osr_block->start_sp());
 207 
 208   // Check bailouts.  We currently do not perform on stack replacement
 209   // of loops in catch blocks or loops which branch with a non-empty stack.
 210   if (sp() != 0) {
 211     C->record_method_not_compilable("OSR starts with non-empty stack");
 212     return;
 213   }
 214   // Do not OSR inside finally clauses:
 215   if (osr_block->has_trap_at(osr_block->start())) {
 216     C->record_method_not_compilable("OSR starts with an immediate trap");
 217     return;
 218   }
 219 
 220   // Commute monitors from interpreter frame to compiler frame.
 221   assert(jvms()->monitor_depth() == 0, "should be no active locks at beginning of osr");
 222   int mcnt = osr_block->flow()->monitor_count();
 223   Node *monitors_addr = basic_plus_adr(osr_buf, osr_buf, (max_locals+mcnt*2-1)*wordSize);
 224   for (index = 0; index < mcnt; index++) {
 225     // Make a BoxLockNode for the monitor.
 226     Node *box = _gvn.transform(new BoxLockNode(next_monitor()));
 227 
 228 
 229     // Displaced headers and locked objects are interleaved in the
 230     // temp OSR buffer.  We only copy the locked objects out here.
 231     // Fetch the locked object from the OSR temp buffer and copy to our fastlock node.
 232     Node *lock_object = fetch_interpreter_state(index*2, T_OBJECT, monitors_addr, osr_buf);
 233     // Try and copy the displaced header to the BoxNode
 234     Node *displaced_hdr = fetch_interpreter_state((index*2) + 1, T_ADDRESS, monitors_addr, osr_buf);
 235 
 236 
 237     store_to_memory(control(), box, displaced_hdr, T_ADDRESS, Compile::AliasIdxRaw, MemNode::unordered);
 238 
 239     // Build a bogus FastLockNode (no code will be generated) and push the
 240     // monitor into our debug info.
 241     const FastLockNode *flock = _gvn.transform(new FastLockNode( 0, lock_object, box ))->as_FastLock();
 242     map()->push_monitor(flock);
 243 
 244     // If the lock is our method synchronization lock, tuck it away in
 245     // _sync_lock for return and rethrow exit paths.
 246     if (index == 0 && method()->is_synchronized()) {
 247       _synch_lock = flock;
 248     }
 249   }
 250 
 251   // Use the raw liveness computation to make sure that unexpected
 252   // values don't propagate into the OSR frame.
 253   MethodLivenessResult live_locals = method()->liveness_at_bci(osr_bci());
 254   if (!live_locals.is_valid()) {
 255     // Degenerate or breakpointed method.
 256     C->record_method_not_compilable("OSR in empty or breakpointed method");
 257     return;
 258   }
 259 
 260   // Extract the needed locals from the interpreter frame.
 261   Node *locals_addr = basic_plus_adr(osr_buf, osr_buf, (max_locals-1)*wordSize);
 262 
 263   // find all the locals that the interpreter thinks contain live oops
 264   const ResourceBitMap live_oops = method()->live_local_oops_at_bci(osr_bci());
 265   for (index = 0; index < max_locals; index++) {
 266 
 267     if (!live_locals.at(index)) {
 268       continue;
 269     }
 270 
 271     const Type *type = osr_block->local_type_at(index);
 272 
 273     if (type->isa_oopptr() != NULL) {
 274 
 275       // 6403625: Verify that the interpreter oopMap thinks that the oop is live
 276       // else we might load a stale oop if the MethodLiveness disagrees with the
 277       // result of the interpreter. If the interpreter says it is dead we agree
 278       // by making the value go to top.
 279       //
 280 
 281       if (!live_oops.at(index)) {
 282         if (C->log() != NULL) {
 283           C->log()->elem("OSR_mismatch local_index='%d'",index);
 284         }
 285         set_local(index, null());
 286         // and ignore it for the loads
 287         continue;
 288       }
 289     }
 290 
 291     // Filter out TOP, HALF, and BOTTOM.  (Cf. ensure_phi.)
 292     if (type == Type::TOP || type == Type::HALF) {
 293       continue;
 294     }
 295     // If the type falls to bottom, then this must be a local that
 296     // is mixing ints and oops or some such.  Forcing it to top
 297     // makes it go dead.
 298     if (type == Type::BOTTOM) {
 299       continue;
 300     }
 301     // Construct code to access the appropriate local.
 302     BasicType bt = type->basic_type();
 303     if (type == TypePtr::NULL_PTR) {
 304       // Ptr types are mixed together with T_ADDRESS but NULL is
 305       // really for T_OBJECT types so correct it.
 306       bt = T_OBJECT;
 307     }
 308     Node *value = fetch_interpreter_state(index, bt, locals_addr, osr_buf);
 309     set_local(index, value);
 310   }
 311 
 312   // Extract the needed stack entries from the interpreter frame.
 313   for (index = 0; index < sp(); index++) {
 314     const Type *type = osr_block->stack_type_at(index);
 315     if (type != Type::TOP) {
 316       // Currently the compiler bails out when attempting to on stack replace
 317       // at a bci with a non-empty stack.  We should not reach here.
 318       ShouldNotReachHere();
 319     }
 320   }
 321 
 322   // End the OSR migration
 323   make_runtime_call(RC_LEAF, OptoRuntime::osr_end_Type(),
 324                     CAST_FROM_FN_PTR(address, SharedRuntime::OSR_migration_end),
 325                     "OSR_migration_end", TypeRawPtr::BOTTOM,
 326                     osr_buf);
 327 
 328   // Now that the interpreter state is loaded, make sure it will match
 329   // at execution time what the compiler is expecting now:
 330   SafePointNode* bad_type_exit = clone_map();
 331   bad_type_exit->set_control(new RegionNode(1));
 332 
 333   assert(osr_block->flow()->jsrs()->size() == 0, "should be no jsrs live at osr point");
 334   for (index = 0; index < max_locals; index++) {
 335     if (stopped())  break;
 336     Node* l = local(index);
 337     if (l->is_top())  continue;  // nothing here
 338     const Type *type = osr_block->local_type_at(index);
 339     if (type->isa_oopptr() != NULL) {
 340       if (!live_oops.at(index)) {
 341         // skip type check for dead oops
 342         continue;
 343       }
 344     }
 345     if (osr_block->flow()->local_type_at(index)->is_return_address()) {
 346       // In our current system it's illegal for jsr addresses to be
 347       // live into an OSR entry point because the compiler performs
 348       // inlining of jsrs.  ciTypeFlow has a bailout that detect this
 349       // case and aborts the compile if addresses are live into an OSR
 350       // entry point.  Because of that we can assume that any address
 351       // locals at the OSR entry point are dead.  Method liveness
 352       // isn't precise enough to figure out that they are dead in all
 353       // cases so simply skip checking address locals all
 354       // together. Any type check is guaranteed to fail since the
 355       // interpreter type is the result of a load which might have any
 356       // value and the expected type is a constant.
 357       continue;
 358     }
 359     set_local(index, check_interpreter_type(l, type, bad_type_exit));
 360   }
 361 
 362   for (index = 0; index < sp(); index++) {
 363     if (stopped())  break;
 364     Node* l = stack(index);
 365     if (l->is_top())  continue;  // nothing here
 366     const Type *type = osr_block->stack_type_at(index);
 367     set_stack(index, check_interpreter_type(l, type, bad_type_exit));
 368   }
 369 
 370   if (bad_type_exit->control()->req() > 1) {
 371     // Build an uncommon trap here, if any inputs can be unexpected.
 372     bad_type_exit->set_control(_gvn.transform( bad_type_exit->control() ));
 373     record_for_igvn(bad_type_exit->control());
 374     SafePointNode* types_are_good = map();
 375     set_map(bad_type_exit);
 376     // The unexpected type happens because a new edge is active
 377     // in the CFG, which typeflow had previously ignored.
 378     // E.g., Object x = coldAtFirst() && notReached()? "str": new Integer(123).
 379     // This x will be typed as Integer if notReached is not yet linked.
 380     // It could also happen due to a problem in ciTypeFlow analysis.
 381     uncommon_trap(Deoptimization::Reason_constraint,
 382                   Deoptimization::Action_reinterpret);
 383     set_map(types_are_good);
 384   }
 385 }
 386 
 387 //------------------------------Parse------------------------------------------
 388 // Main parser constructor.
 389 Parse::Parse(JVMState* caller, ciMethod* parse_method, float expected_uses)
 390   : _exits(caller)
 391 {
 392   // Init some variables
 393   _caller = caller;
 394   _method = parse_method;
 395   _expected_uses = expected_uses;
 396   _depth = 1 + (caller->has_method() ? caller->depth() : 0);
 397   _wrote_final = false;
 398   _wrote_volatile = false;
 399   _wrote_stable = false;
 400   _wrote_fields = false;
 401   _alloc_with_final = NULL;
 402   _entry_bci = InvocationEntryBci;
 403   _tf = NULL;
 404   _block = NULL;
 405   _first_return = true;
 406   _replaced_nodes_for_exceptions = false;
 407   _new_idx = C->unique();
 408   debug_only(_block_count = -1);
 409   debug_only(_blocks = (Block*)-1);
 410 #ifndef PRODUCT
 411   if (PrintCompilation || PrintOpto) {
 412     // Make sure I have an inline tree, so I can print messages about it.
 413     JVMState* ilt_caller = is_osr_parse() ? caller->caller() : caller;
 414     InlineTree::find_subtree_from_root(C->ilt(), ilt_caller, parse_method);
 415   }
 416   _max_switch_depth = 0;
 417   _est_switch_depth = 0;
 418 #endif
 419 
 420   if (parse_method->has_reserved_stack_access()) {
 421     C->set_has_reserved_stack_access(true);
 422   }
 423 
 424   if (parse_method->is_synchronized()) {
 425     C->set_has_monitors(true);
 426     C->push_monitor();
 427   }
 428 
 429   _tf = TypeFunc::make(method());
 430   _iter.reset_to_method(method());
 431   _flow = method()->get_flow_analysis();
 432   if (_flow->failing()) {
 433     C->record_method_not_compilable(_flow->failure_reason());
 434   }
 435 
 436 #ifndef PRODUCT
 437   if (_flow->has_irreducible_entry()) {
 438     C->set_parsed_irreducible_loop(true);
 439   }
 440 #endif
 441   C->set_has_loops(C->has_loops() || method()->has_loops());
 442 
 443   if (_expected_uses <= 0) {
 444     _prof_factor = 1;
 445   } else {
 446     float prof_total = parse_method->interpreter_invocation_count();
 447     if (prof_total <= _expected_uses) {
 448       _prof_factor = 1;
 449     } else {
 450       _prof_factor = _expected_uses / prof_total;
 451     }
 452   }
 453 
 454   CompileLog* log = C->log();
 455   if (log != NULL) {
 456     log->begin_head("parse method='%d' uses='%f'",
 457                     log->identify(parse_method), expected_uses);
 458     if (depth() == 1 && C->is_osr_compilation()) {
 459       log->print(" osr_bci='%d'", C->entry_bci());
 460     }
 461     log->stamp();
 462     log->end_head();
 463   }
 464 
 465   // Accumulate deoptimization counts.
 466   // (The range_check and store_check counts are checked elsewhere.)
 467   ciMethodData* md = method()->method_data();
 468   for (uint reason = 0; reason < md->trap_reason_limit(); reason++) {
 469     uint md_count = md->trap_count(reason);
 470     if (md_count != 0) {
 471       if (md_count >= md->trap_count_limit()) {
 472         md_count = md->trap_count_limit() + md->overflow_trap_count();
 473       }
 474       uint total_count = C->trap_count(reason);
 475       uint old_count   = total_count;
 476       total_count += md_count;
 477       // Saturate the add if it overflows.
 478       if (total_count < old_count || total_count < md_count)
 479         total_count = (uint)-1;
 480       C->set_trap_count(reason, total_count);
 481       if (log != NULL)
 482         log->elem("observe trap='%s' count='%d' total='%d'",
 483                   Deoptimization::trap_reason_name(reason),
 484                   md_count, total_count);
 485     }
 486   }
 487   // Accumulate total sum of decompilations, also.
 488   C->set_decompile_count(C->decompile_count() + md->decompile_count());
 489 
 490   if (log != NULL && method()->has_exception_handlers()) {
 491     log->elem("observe that='has_exception_handlers'");
 492   }
 493 
 494   assert(InlineTree::check_can_parse(method()) == NULL, "Can not parse this method, cutout earlier");
 495   assert(method()->has_balanced_monitors(), "Can not parse unbalanced monitors, cutout earlier");
 496 
 497   // Always register dependence if JVMTI is enabled, because
 498   // either breakpoint setting or hotswapping of methods may
 499   // cause deoptimization.
 500   if (C->env()->jvmti_can_hotswap_or_post_breakpoint()) {
 501     C->dependencies()->assert_evol_method(method());
 502   }
 503 
 504   NOT_PRODUCT(methods_seen++);
 505 
 506   // Do some special top-level things.
 507   if (depth() == 1 && C->is_osr_compilation()) {
 508     _entry_bci = C->entry_bci();
 509     _flow = method()->get_osr_flow_analysis(osr_bci());
 510     if (_flow->failing()) {
 511       C->record_method_not_compilable(_flow->failure_reason());
 512 #ifndef PRODUCT
 513       if (PrintOpto && (Verbose || WizardMode)) {
 514         tty->print_cr("OSR @%d type flow bailout: %s", _entry_bci, _flow->failure_reason());
 515         if (Verbose) {
 516           method()->print();
 517           method()->print_codes();
 518           _flow->print();
 519         }
 520       }
 521 #endif
 522     }
 523     _tf = C->tf();     // the OSR entry type is different
 524   }
 525 
 526 #ifdef ASSERT
 527   if (depth() == 1) {
 528     assert(C->is_osr_compilation() == this->is_osr_parse(), "OSR in sync");
 529   } else {
 530     assert(!this->is_osr_parse(), "no recursive OSR");
 531   }
 532 #endif
 533 
 534 #ifndef PRODUCT
 535   methods_parsed++;
 536   // add method size here to guarantee that inlined methods are added too
 537   if (CITime)
 538     _total_bytes_compiled += method()->code_size();
 539 
 540   show_parse_info();
 541 #endif
 542 
 543   if (failing()) {
 544     if (log)  log->done("parse");
 545     return;
 546   }
 547 
 548   gvn().transform(top());
 549 
 550   // Import the results of the ciTypeFlow.
 551   init_blocks();
 552 
 553   // Merge point for all normal exits
 554   build_exits();
 555 
 556   // Setup the initial JVM state map.
 557   SafePointNode* entry_map = create_entry_map();
 558 
 559   // Check for bailouts during map initialization
 560   if (failing() || entry_map == NULL) {
 561     if (log)  log->done("parse");
 562     return;
 563   }
 564 
 565   Node_Notes* caller_nn = C->default_node_notes();
 566   // Collect debug info for inlined calls unless -XX:-DebugInlinedCalls.
 567   if (DebugInlinedCalls || depth() == 1) {
 568     C->set_default_node_notes(make_node_notes(caller_nn));
 569   }
 570 
 571   if (is_osr_parse()) {
 572     Node* osr_buf = entry_map->in(TypeFunc::Parms+0);
 573     entry_map->set_req(TypeFunc::Parms+0, top());
 574     set_map(entry_map);
 575     load_interpreter_state(osr_buf);
 576   } else {
 577     set_map(entry_map);
 578     do_method_entry();
 579   }
 580 
 581   if (depth() == 1 && !failing()) {
 582     if (C->clinit_barrier_on_entry()) {
 583       // Add check to deoptimize the nmethod once the holder class is fully initialized
 584       clinit_deopt();
 585     }
 586 
 587     // Add check to deoptimize the nmethod if RTM state was changed
 588     rtm_deopt();
 589   }
 590 
 591   // Check for bailouts during method entry or RTM state check setup.
 592   if (failing()) {
 593     if (log)  log->done("parse");
 594     C->set_default_node_notes(caller_nn);
 595     return;
 596   }
 597 
 598   entry_map = map();  // capture any changes performed by method setup code
 599   assert(jvms()->endoff() == map()->req(), "map matches JVMS layout");
 600 
 601   // We begin parsing as if we have just encountered a jump to the
 602   // method entry.
 603   Block* entry_block = start_block();
 604   assert(entry_block->start() == (is_osr_parse() ? osr_bci() : 0), "");
 605   set_map_clone(entry_map);
 606   merge_common(entry_block, entry_block->next_path_num());
 607 
 608 #ifndef PRODUCT
 609   BytecodeParseHistogram *parse_histogram_obj = new (C->env()->arena()) BytecodeParseHistogram(this, C);
 610   set_parse_histogram( parse_histogram_obj );
 611 #endif
 612 
 613   // Parse all the basic blocks.
 614   do_all_blocks();
 615 
 616   C->set_default_node_notes(caller_nn);
 617 
 618   // Check for bailouts during conversion to graph
 619   if (failing()) {
 620     if (log)  log->done("parse");
 621     return;
 622   }
 623 
 624   // Fix up all exiting control flow.
 625   set_map(entry_map);
 626   do_exits();
 627 
 628   if (log)  log->done("parse nodes='%d' live='%d' memory='" SIZE_FORMAT "'",
 629                       C->unique(), C->live_nodes(), C->node_arena()->used());
 630 }
 631 
 632 //---------------------------do_all_blocks-------------------------------------
 633 void Parse::do_all_blocks() {
 634   bool has_irreducible = flow()->has_irreducible_entry();
 635 
 636   // Walk over all blocks in Reverse Post-Order.
 637   while (true) {
 638     bool progress = false;
 639     for (int rpo = 0; rpo < block_count(); rpo++) {
 640       Block* block = rpo_at(rpo);
 641 
 642       if (block->is_parsed()) continue;
 643 
 644       if (!block->is_merged()) {
 645         // Dead block, no state reaches this block
 646         continue;
 647       }
 648 
 649       // Prepare to parse this block.
 650       load_state_from(block);
 651 
 652       if (stopped()) {
 653         // Block is dead.
 654         continue;
 655       }
 656 
 657       NOT_PRODUCT(blocks_parsed++);
 658 
 659       progress = true;
 660       if (block->is_loop_head() || block->is_handler() || (has_irreducible && !block->is_ready())) {
 661         // Not all preds have been parsed.  We must build phis everywhere.
 662         // (Note that dead locals do not get phis built, ever.)
 663         ensure_phis_everywhere();
 664 
 665         if (block->is_SEL_head()) {
 666           // Add predicate to single entry (not irreducible) loop head.
 667           assert(!block->has_merged_backedge(), "only entry paths should be merged for now");
 668           // Predicates may have been added after a dominating if
 669           if (!block->has_predicates()) {
 670             // Need correct bci for predicate.
 671             // It is fine to set it here since do_one_block() will set it anyway.
 672             set_parse_bci(block->start());
 673             add_empty_predicates();
 674           }
 675           // Add new region for back branches.
 676           int edges = block->pred_count() - block->preds_parsed() + 1; // +1 for original region
 677           RegionNode *r = new RegionNode(edges+1);
 678           _gvn.set_type(r, Type::CONTROL);
 679           record_for_igvn(r);
 680           r->init_req(edges, control());
 681           set_control(r);
 682           block->copy_irreducible_status_to(r, jvms());
 683           // Add new phis.
 684           ensure_phis_everywhere();
 685         }
 686 
 687         // Leave behind an undisturbed copy of the map, for future merges.
 688         set_map(clone_map());
 689       }
 690 
 691       if (control()->is_Region() && !block->is_loop_head() && !has_irreducible && !block->is_handler()) {
 692         // In the absence of irreducible loops, the Region and Phis
 693         // associated with a merge that doesn't involve a backedge can
 694         // be simplified now since the RPO parsing order guarantees
 695         // that any path which was supposed to reach here has already
 696         // been parsed or must be dead.
 697         Node* c = control();
 698         Node* result = _gvn.transform_no_reclaim(control());
 699         if (c != result && TraceOptoParse) {
 700           tty->print_cr("Block #%d replace %d with %d", block->rpo(), c->_idx, result->_idx);
 701         }
 702         if (result != top()) {
 703           record_for_igvn(result);
 704         }
 705       }
 706 
 707       // Parse the block.
 708       do_one_block();
 709 
 710       // Check for bailouts.
 711       if (failing())  return;
 712     }
 713 
 714     // with irreducible loops multiple passes might be necessary to parse everything
 715     if (!has_irreducible || !progress) {
 716       break;
 717     }
 718   }
 719 
 720 #ifndef PRODUCT
 721   blocks_seen += block_count();
 722 
 723   // Make sure there are no half-processed blocks remaining.
 724   // Every remaining unprocessed block is dead and may be ignored now.
 725   for (int rpo = 0; rpo < block_count(); rpo++) {
 726     Block* block = rpo_at(rpo);
 727     if (!block->is_parsed()) {
 728       if (TraceOptoParse) {
 729         tty->print_cr("Skipped dead block %d at bci:%d", rpo, block->start());
 730       }
 731       assert(!block->is_merged(), "no half-processed blocks");
 732     }
 733   }
 734 #endif
 735 }
 736 
 737 static Node* mask_int_value(Node* v, BasicType bt, PhaseGVN* gvn) {
 738   switch (bt) {
 739   case T_BYTE:
 740     v = gvn->transform(new LShiftINode(v, gvn->intcon(24)));
 741     v = gvn->transform(new RShiftINode(v, gvn->intcon(24)));
 742     break;
 743   case T_SHORT:
 744     v = gvn->transform(new LShiftINode(v, gvn->intcon(16)));
 745     v = gvn->transform(new RShiftINode(v, gvn->intcon(16)));
 746     break;
 747   case T_CHAR:
 748     v = gvn->transform(new AndINode(v, gvn->intcon(0xFFFF)));
 749     break;
 750   case T_BOOLEAN:
 751     v = gvn->transform(new AndINode(v, gvn->intcon(0x1)));
 752     break;
 753   default:
 754     break;
 755   }
 756   return v;
 757 }
 758 
 759 //-------------------------------build_exits----------------------------------
 760 // Build normal and exceptional exit merge points.
 761 void Parse::build_exits() {
 762   // make a clone of caller to prevent sharing of side-effects
 763   _exits.set_map(_exits.clone_map());
 764   _exits.clean_stack(_exits.sp());
 765   _exits.sync_jvms();
 766 
 767   RegionNode* region = new RegionNode(1);
 768   record_for_igvn(region);
 769   gvn().set_type_bottom(region);
 770   _exits.set_control(region);
 771 
 772   // Note:  iophi and memphi are not transformed until do_exits.
 773   Node* iophi  = new PhiNode(region, Type::ABIO);
 774   Node* memphi = new PhiNode(region, Type::MEMORY, TypePtr::BOTTOM);
 775   gvn().set_type_bottom(iophi);
 776   gvn().set_type_bottom(memphi);
 777   _exits.set_i_o(iophi);
 778   _exits.set_all_memory(memphi);
 779 
 780   // Add a return value to the exit state.  (Do not push it yet.)
 781   if (tf()->range()->cnt() > TypeFunc::Parms) {
 782     const Type* ret_type = tf()->range()->field_at(TypeFunc::Parms);
 783     if (ret_type->isa_int()) {
 784       BasicType ret_bt = method()->return_type()->basic_type();
 785       if (ret_bt == T_BOOLEAN ||
 786           ret_bt == T_CHAR ||
 787           ret_bt == T_BYTE ||
 788           ret_bt == T_SHORT) {
 789         ret_type = TypeInt::INT;
 790       }
 791     }
 792 
 793     // Don't "bind" an unloaded return klass to the ret_phi. If the klass
 794     // becomes loaded during the subsequent parsing, the loaded and unloaded
 795     // types will not join when we transform and push in do_exits().
 796     const TypeOopPtr* ret_oop_type = ret_type->isa_oopptr();
 797     if (ret_oop_type && !ret_oop_type->is_loaded()) {
 798       ret_type = TypeOopPtr::BOTTOM;
 799     }
 800     int         ret_size = type2size[ret_type->basic_type()];
 801     Node*       ret_phi  = new PhiNode(region, ret_type);
 802     gvn().set_type_bottom(ret_phi);
 803     _exits.ensure_stack(ret_size);
 804     assert((int)(tf()->range()->cnt() - TypeFunc::Parms) == ret_size, "good tf range");
 805     assert(method()->return_type()->size() == ret_size, "tf agrees w/ method");
 806     _exits.set_argument(0, ret_phi);  // here is where the parser finds it
 807     // Note:  ret_phi is not yet pushed, until do_exits.
 808   }
 809 }
 810 
 811 
 812 //----------------------------build_start_state-------------------------------
 813 // Construct a state which contains only the incoming arguments from an
 814 // unknown caller.  The method & bci will be NULL & InvocationEntryBci.
 815 JVMState* Compile::build_start_state(StartNode* start, const TypeFunc* tf) {
 816   int        arg_size = tf->domain()->cnt();
 817   int        max_size = MAX2(arg_size, (int)tf->range()->cnt());
 818   JVMState*  jvms     = new (this) JVMState(max_size - TypeFunc::Parms);
 819   SafePointNode* map  = new SafePointNode(max_size, jvms);
 820   record_for_igvn(map);
 821   assert(arg_size == TypeFunc::Parms + (is_osr_compilation() ? 1 : method()->arg_size()), "correct arg_size");
 822   Node_Notes* old_nn = default_node_notes();
 823   if (old_nn != NULL && has_method()) {
 824     Node_Notes* entry_nn = old_nn->clone(this);
 825     JVMState* entry_jvms = new(this) JVMState(method(), old_nn->jvms());
 826     entry_jvms->set_offsets(0);
 827     entry_jvms->set_bci(entry_bci());
 828     entry_nn->set_jvms(entry_jvms);
 829     set_default_node_notes(entry_nn);
 830   }
 831   uint i;
 832   for (i = 0; i < (uint)arg_size; i++) {
 833     Node* parm = initial_gvn()->transform(new ParmNode(start, i));
 834     map->init_req(i, parm);
 835     // Record all these guys for later GVN.
 836     record_for_igvn(parm);
 837   }
 838   for (; i < map->req(); i++) {
 839     map->init_req(i, top());
 840   }
 841   assert(jvms->argoff() == TypeFunc::Parms, "parser gets arguments here");
 842   set_default_node_notes(old_nn);
 843   jvms->set_map(map);
 844   return jvms;
 845 }
 846 
 847 //-----------------------------make_node_notes---------------------------------
 848 Node_Notes* Parse::make_node_notes(Node_Notes* caller_nn) {
 849   if (caller_nn == NULL)  return NULL;
 850   Node_Notes* nn = caller_nn->clone(C);
 851   JVMState* caller_jvms = nn->jvms();
 852   JVMState* jvms = new (C) JVMState(method(), caller_jvms);
 853   jvms->set_offsets(0);
 854   jvms->set_bci(_entry_bci);
 855   nn->set_jvms(jvms);
 856   return nn;
 857 }
 858 
 859 
 860 //--------------------------return_values--------------------------------------
 861 void Compile::return_values(JVMState* jvms) {
 862   GraphKit kit(jvms);
 863   Node* ret = new ReturnNode(TypeFunc::Parms,
 864                              kit.control(),
 865                              kit.i_o(),
 866                              kit.reset_memory(),
 867                              kit.frameptr(),
 868                              kit.returnadr());
 869   // Add zero or 1 return values
 870   int ret_size = tf()->range()->cnt() - TypeFunc::Parms;
 871   if (ret_size > 0) {
 872     kit.inc_sp(-ret_size);  // pop the return value(s)
 873     kit.sync_jvms();
 874     ret->add_req(kit.argument(0));
 875     // Note:  The second dummy edge is not needed by a ReturnNode.
 876   }
 877   // bind it to root
 878   root()->add_req(ret);
 879   record_for_igvn(ret);
 880   initial_gvn()->transform_no_reclaim(ret);
 881 }
 882 
 883 //------------------------rethrow_exceptions-----------------------------------
 884 // Bind all exception states in the list into a single RethrowNode.
 885 void Compile::rethrow_exceptions(JVMState* jvms) {
 886   GraphKit kit(jvms);
 887   if (!kit.has_exceptions())  return;  // nothing to generate
 888   // Load my combined exception state into the kit, with all phis transformed:
 889   SafePointNode* ex_map = kit.combine_and_pop_all_exception_states();
 890   Node* ex_oop = kit.use_exception_state(ex_map);
 891   RethrowNode* exit = new RethrowNode(kit.control(),
 892                                       kit.i_o(), kit.reset_memory(),
 893                                       kit.frameptr(), kit.returnadr(),
 894                                       // like a return but with exception input
 895                                       ex_oop);
 896   // bind to root
 897   root()->add_req(exit);
 898   record_for_igvn(exit);
 899   initial_gvn()->transform_no_reclaim(exit);
 900 }
 901 
 902 //---------------------------do_exceptions-------------------------------------
 903 // Process exceptions arising from the current bytecode.
 904 // Send caught exceptions to the proper handler within this method.
 905 // Unhandled exceptions feed into _exit.
 906 void Parse::do_exceptions() {
 907   if (!has_exceptions())  return;
 908 
 909   if (failing()) {
 910     // Pop them all off and throw them away.
 911     while (pop_exception_state() != NULL) ;
 912     return;
 913   }
 914 
 915   PreserveJVMState pjvms(this, false);
 916 
 917   SafePointNode* ex_map;
 918   while ((ex_map = pop_exception_state()) != NULL) {
 919     if (!method()->has_exception_handlers()) {
 920       // Common case:  Transfer control outward.
 921       // Doing it this early allows the exceptions to common up
 922       // even between adjacent method calls.
 923       throw_to_exit(ex_map);
 924     } else {
 925       // Have to look at the exception first.
 926       assert(stopped(), "catch_inline_exceptions trashes the map");
 927       catch_inline_exceptions(ex_map);
 928       stop_and_kill_map();      // we used up this exception state; kill it
 929     }
 930   }
 931 
 932   // We now return to our regularly scheduled program:
 933 }
 934 
 935 //---------------------------throw_to_exit-------------------------------------
 936 // Merge the given map into an exception exit from this method.
 937 // The exception exit will handle any unlocking of receiver.
 938 // The ex_oop must be saved within the ex_map, unlike merge_exception.
 939 void Parse::throw_to_exit(SafePointNode* ex_map) {
 940   // Pop the JVMS to (a copy of) the caller.
 941   GraphKit caller;
 942   caller.set_map_clone(_caller->map());
 943   caller.set_bci(_caller->bci());
 944   caller.set_sp(_caller->sp());
 945   // Copy out the standard machine state:
 946   for (uint i = 0; i < TypeFunc::Parms; i++) {
 947     caller.map()->set_req(i, ex_map->in(i));
 948   }
 949   if (ex_map->has_replaced_nodes()) {
 950     _replaced_nodes_for_exceptions = true;
 951   }
 952   caller.map()->transfer_replaced_nodes_from(ex_map, _new_idx);
 953   // ...and the exception:
 954   Node*          ex_oop        = saved_ex_oop(ex_map);
 955   SafePointNode* caller_ex_map = caller.make_exception_state(ex_oop);
 956   // Finally, collect the new exception state in my exits:
 957   _exits.add_exception_state(caller_ex_map);
 958 }
 959 
 960 //------------------------------do_exits---------------------------------------
 961 void Parse::do_exits() {
 962   set_parse_bci(InvocationEntryBci);
 963 
 964   // Now peephole on the return bits
 965   Node* region = _exits.control();
 966   _exits.set_control(gvn().transform(region));
 967 
 968   Node* iophi = _exits.i_o();
 969   _exits.set_i_o(gvn().transform(iophi));
 970 
 971   // Figure out if we need to emit the trailing barrier. The barrier is only
 972   // needed in the constructors, and only in three cases:
 973   //
 974   // 1. The constructor wrote a final. The effects of all initializations
 975   //    must be committed to memory before any code after the constructor
 976   //    publishes the reference to the newly constructed object. Rather
 977   //    than wait for the publication, we simply block the writes here.
 978   //    Rather than put a barrier on only those writes which are required
 979   //    to complete, we force all writes to complete.
 980   //
 981   // 2. Experimental VM option is used to force the barrier if any field
 982   //    was written out in the constructor.
 983   //
 984   // 3. On processors which are not CPU_MULTI_COPY_ATOMIC (e.g. PPC64),
 985   //    support_IRIW_for_not_multiple_copy_atomic_cpu selects that
 986   //    MemBarVolatile is used before volatile load instead of after volatile
 987   //    store, so there's no barrier after the store.
 988   //    We want to guarantee the same behavior as on platforms with total store
 989   //    order, although this is not required by the Java memory model.
 990   //    In this case, we want to enforce visibility of volatile field
 991   //    initializations which are performed in constructors.
 992   //    So as with finals, we add a barrier here.
 993   //
 994   // "All bets are off" unless the first publication occurs after a
 995   // normal return from the constructor.  We do not attempt to detect
 996   // such unusual early publications.  But no barrier is needed on
 997   // exceptional returns, since they cannot publish normally.
 998   //
 999   if (method()->is_initializer() &&
1000        (wrote_final() ||
1001          (AlwaysSafeConstructors && wrote_fields()) ||
1002          (support_IRIW_for_not_multiple_copy_atomic_cpu && wrote_volatile()))) {
1003     _exits.insert_mem_bar(Op_MemBarRelease, alloc_with_final());
1004 
1005     // If Memory barrier is created for final fields write
1006     // and allocation node does not escape the initialize method,
1007     // then barrier introduced by allocation node can be removed.
1008     if (DoEscapeAnalysis && alloc_with_final()) {
1009       AllocateNode *alloc = AllocateNode::Ideal_allocation(alloc_with_final(), &_gvn);
1010       alloc->compute_MemBar_redundancy(method());
1011     }
1012     if (PrintOpto && (Verbose || WizardMode)) {
1013       method()->print_name();
1014       tty->print_cr(" writes finals and needs a memory barrier");
1015     }
1016   }
1017 
1018   // Any method can write a @Stable field; insert memory barriers
1019   // after those also. Can't bind predecessor allocation node (if any)
1020   // with barrier because allocation doesn't always dominate
1021   // MemBarRelease.
1022   if (wrote_stable()) {
1023     _exits.insert_mem_bar(Op_MemBarRelease);
1024     if (PrintOpto && (Verbose || WizardMode)) {
1025       method()->print_name();
1026       tty->print_cr(" writes @Stable and needs a memory barrier");
1027     }
1028   }
1029 
1030   for (MergeMemStream mms(_exits.merged_memory()); mms.next_non_empty(); ) {
1031     // transform each slice of the original memphi:
1032     mms.set_memory(_gvn.transform(mms.memory()));
1033   }
1034   // Clean up input MergeMems created by transforming the slices
1035   _gvn.transform(_exits.merged_memory());
1036 
1037   if (tf()->range()->cnt() > TypeFunc::Parms) {
1038     const Type* ret_type = tf()->range()->field_at(TypeFunc::Parms);
1039     Node*       ret_phi  = _gvn.transform( _exits.argument(0) );
1040     if (!_exits.control()->is_top() && _gvn.type(ret_phi)->empty()) {
1041       // If the type we set for the ret_phi in build_exits() is too optimistic and
1042       // the ret_phi is top now, there's an extremely small chance that it may be due to class
1043       // loading.  It could also be due to an error, so mark this method as not compilable because
1044       // otherwise this could lead to an infinite compile loop.
1045       // In any case, this code path is rarely (and never in my testing) reached.
1046       C->record_method_not_compilable("Can't determine return type.");
1047       return;
1048     }
1049     if (ret_type->isa_int()) {
1050       BasicType ret_bt = method()->return_type()->basic_type();
1051       ret_phi = mask_int_value(ret_phi, ret_bt, &_gvn);
1052     }
1053     _exits.push_node(ret_type->basic_type(), ret_phi);
1054   }
1055 
1056   // Note:  Logic for creating and optimizing the ReturnNode is in Compile.
1057 
1058   // Unlock along the exceptional paths.
1059   // This is done late so that we can common up equivalent exceptions
1060   // (e.g., null checks) arising from multiple points within this method.
1061   // See GraphKit::add_exception_state, which performs the commoning.
1062   bool do_synch = method()->is_synchronized() && GenerateSynchronizationCode;
1063 
1064   // record exit from a method if compiled while Dtrace is turned on.
1065   if (do_synch || C->env()->dtrace_method_probes() || _replaced_nodes_for_exceptions) {
1066     // First move the exception list out of _exits:
1067     GraphKit kit(_exits.transfer_exceptions_into_jvms());
1068     SafePointNode* normal_map = kit.map();  // keep this guy safe
1069     // Now re-collect the exceptions into _exits:
1070     SafePointNode* ex_map;
1071     while ((ex_map = kit.pop_exception_state()) != NULL) {
1072       Node* ex_oop = kit.use_exception_state(ex_map);
1073       // Force the exiting JVM state to have this method at InvocationEntryBci.
1074       // The exiting JVM state is otherwise a copy of the calling JVMS.
1075       JVMState* caller = kit.jvms();
1076       JVMState* ex_jvms = caller->clone_shallow(C);
1077       ex_jvms->bind_map(kit.clone_map());
1078       ex_jvms->set_bci(   InvocationEntryBci);
1079       kit.set_jvms(ex_jvms);
1080       if (do_synch) {
1081         // Add on the synchronized-method box/object combo
1082         kit.map()->push_monitor(_synch_lock);
1083         // Unlock!
1084         kit.shared_unlock(_synch_lock->box_node(), _synch_lock->obj_node());
1085       }
1086       if (C->env()->dtrace_method_probes()) {
1087         kit.make_dtrace_method_exit(method());
1088       }
1089       if (_replaced_nodes_for_exceptions) {
1090         kit.map()->apply_replaced_nodes(_new_idx);
1091       }
1092       // Done with exception-path processing.
1093       ex_map = kit.make_exception_state(ex_oop);
1094       assert(ex_jvms->same_calls_as(ex_map->jvms()), "sanity");
1095       // Pop the last vestige of this method:
1096       caller->clone_shallow(C)->bind_map(ex_map);
1097       _exits.push_exception_state(ex_map);
1098     }
1099     assert(_exits.map() == normal_map, "keep the same return state");
1100   }
1101 
1102   {
1103     // Capture very early exceptions (receiver null checks) from caller JVMS
1104     GraphKit caller(_caller);
1105     SafePointNode* ex_map;
1106     while ((ex_map = caller.pop_exception_state()) != NULL) {
1107       _exits.add_exception_state(ex_map);
1108     }
1109   }
1110   _exits.map()->apply_replaced_nodes(_new_idx);
1111 }
1112 
1113 //-----------------------------create_entry_map-------------------------------
1114 // Initialize our parser map to contain the types at method entry.
1115 // For OSR, the map contains a single RawPtr parameter.
1116 // Initial monitor locking for sync. methods is performed by do_method_entry.
1117 SafePointNode* Parse::create_entry_map() {
1118   // Check for really stupid bail-out cases.
1119   uint len = TypeFunc::Parms + method()->max_locals() + method()->max_stack();
1120   if (len >= 32760) {
1121     C->record_method_not_compilable("too many local variables");
1122     return NULL;
1123   }
1124 
1125   // clear current replaced nodes that are of no use from here on (map was cloned in build_exits).
1126   _caller->map()->delete_replaced_nodes();
1127 
1128   // If this is an inlined method, we may have to do a receiver null check.
1129   if (_caller->has_method() && is_normal_parse() && !method()->is_static()) {
1130     GraphKit kit(_caller);
1131     kit.null_check_receiver_before_call(method());
1132     _caller = kit.transfer_exceptions_into_jvms();
1133     if (kit.stopped()) {
1134       _exits.add_exception_states_from(_caller);
1135       _exits.set_jvms(_caller);
1136       return NULL;
1137     }
1138   }
1139 
1140   assert(method() != NULL, "parser must have a method");
1141 
1142   // Create an initial safepoint to hold JVM state during parsing
1143   JVMState* jvms = new (C) JVMState(method(), _caller->has_method() ? _caller : NULL);
1144   set_map(new SafePointNode(len, jvms));
1145   jvms->set_map(map());
1146   record_for_igvn(map());
1147   assert(jvms->endoff() == len, "correct jvms sizing");
1148 
1149   SafePointNode* inmap = _caller->map();
1150   assert(inmap != NULL, "must have inmap");
1151   // In case of null check on receiver above
1152   map()->transfer_replaced_nodes_from(inmap, _new_idx);
1153 
1154   uint i;
1155 
1156   // Pass thru the predefined input parameters.
1157   for (i = 0; i < TypeFunc::Parms; i++) {
1158     map()->init_req(i, inmap->in(i));
1159   }
1160 
1161   if (depth() == 1) {
1162     assert(map()->memory()->Opcode() == Op_Parm, "");
1163     // Insert the memory aliasing node
1164     set_all_memory(reset_memory());
1165   }
1166   assert(merged_memory(), "");
1167 
1168   // Now add the locals which are initially bound to arguments:
1169   uint arg_size = tf()->domain()->cnt();
1170   ensure_stack(arg_size - TypeFunc::Parms);  // OSR methods have funny args
1171   for (i = TypeFunc::Parms; i < arg_size; i++) {
1172     map()->init_req(i, inmap->argument(_caller, i - TypeFunc::Parms));
1173   }
1174 
1175   // Clear out the rest of the map (locals and stack)
1176   for (i = arg_size; i < len; i++) {
1177     map()->init_req(i, top());
1178   }
1179 
1180   SafePointNode* entry_map = stop();
1181   return entry_map;
1182 }
1183 
1184 //-----------------------------do_method_entry--------------------------------
1185 // Emit any code needed in the pseudo-block before BCI zero.
1186 // The main thing to do is lock the receiver of a synchronized method.
1187 void Parse::do_method_entry() {
1188   set_parse_bci(InvocationEntryBci); // Pseudo-BCP
1189   set_sp(0);                         // Java Stack Pointer
1190 
1191   NOT_PRODUCT( count_compiled_calls(true/*at_method_entry*/, false/*is_inline*/); )
1192 
1193   if (C->env()->dtrace_method_probes()) {
1194     make_dtrace_method_entry(method());
1195   }
1196 
1197 #ifdef ASSERT
1198   // Narrow receiver type when it is too broad for the method being parsed.
1199   if (!method()->is_static()) {
1200     ciInstanceKlass* callee_holder = method()->holder();
1201     const Type* holder_type = TypeInstPtr::make(TypePtr::BotPTR, callee_holder, Type::trust_interfaces);
1202 
1203     Node* receiver_obj = local(0);
1204     const TypeInstPtr* receiver_type = _gvn.type(receiver_obj)->isa_instptr();
1205 
1206     if (receiver_type != NULL && !receiver_type->higher_equal(holder_type)) {
1207       // Receiver should always be a subtype of callee holder.
1208       // But, since C2 type system doesn't properly track interfaces,
1209       // the invariant can't be expressed in the type system for default methods.
1210       // Example: for unrelated C <: I and D <: I, (C `meet` D) = Object </: I.
1211       assert(callee_holder->is_interface(), "missing subtype check");
1212 
1213       // Perform dynamic receiver subtype check against callee holder class w/ a halt on failure.
1214       Node* holder_klass = _gvn.makecon(TypeKlassPtr::make(callee_holder, Type::trust_interfaces));
1215       Node* not_subtype_ctrl = gen_subtype_check(receiver_obj, holder_klass);
1216       assert(!stopped(), "not a subtype");
1217 
1218       Node* halt = _gvn.transform(new HaltNode(not_subtype_ctrl, frameptr(), "failed receiver subtype check"));
1219       C->root()->add_req(halt);
1220     }
1221   }
1222 #endif // ASSERT
1223 
1224   // If the method is synchronized, we need to construct a lock node, attach
1225   // it to the Start node, and pin it there.
1226   if (method()->is_synchronized()) {
1227     // Insert a FastLockNode right after the Start which takes as arguments
1228     // the current thread pointer, the "this" pointer & the address of the
1229     // stack slot pair used for the lock.  The "this" pointer is a projection
1230     // off the start node, but the locking spot has to be constructed by
1231     // creating a ConLNode of 0, and boxing it with a BoxLockNode.  The BoxLockNode
1232     // becomes the second argument to the FastLockNode call.  The
1233     // FastLockNode becomes the new control parent to pin it to the start.
1234 
1235     // Setup Object Pointer
1236     Node *lock_obj = NULL;
1237     if (method()->is_static()) {
1238       ciInstance* mirror = _method->holder()->java_mirror();
1239       const TypeInstPtr *t_lock = TypeInstPtr::make(mirror);
1240       lock_obj = makecon(t_lock);
1241     } else {                  // Else pass the "this" pointer,
1242       lock_obj = local(0);    // which is Parm0 from StartNode
1243     }
1244     // Clear out dead values from the debug info.
1245     kill_dead_locals();
1246     // Build the FastLockNode
1247     _synch_lock = shared_lock(lock_obj);
1248   }
1249 
1250   // Feed profiling data for parameters to the type system so it can
1251   // propagate it as speculative types
1252   record_profiled_parameters_for_speculation();
1253 }
1254 
1255 //------------------------------init_blocks------------------------------------
1256 // Initialize our parser map to contain the types/monitors at method entry.
1257 void Parse::init_blocks() {
1258   // Create the blocks.
1259   _block_count = flow()->block_count();
1260   _blocks = NEW_RESOURCE_ARRAY(Block, _block_count);
1261 
1262   // Initialize the structs.
1263   for (int rpo = 0; rpo < block_count(); rpo++) {
1264     Block* block = rpo_at(rpo);
1265     new(block) Block(this, rpo);
1266   }
1267 
1268   // Collect predecessor and successor information.
1269   for (int rpo = 0; rpo < block_count(); rpo++) {
1270     Block* block = rpo_at(rpo);
1271     block->init_graph(this);
1272   }
1273 }
1274 
1275 //-------------------------------init_node-------------------------------------
1276 Parse::Block::Block(Parse* outer, int rpo) : _live_locals() {
1277   _flow = outer->flow()->rpo_at(rpo);
1278   _pred_count = 0;
1279   _preds_parsed = 0;
1280   _count = 0;
1281   _is_parsed = false;
1282   _is_handler = false;
1283   _has_merged_backedge = false;
1284   _start_map = NULL;
1285   _has_predicates = false;
1286   _num_successors = 0;
1287   _all_successors = 0;
1288   _successors = NULL;
1289   assert(pred_count() == 0 && preds_parsed() == 0, "sanity");
1290   assert(!(is_merged() || is_parsed() || is_handler() || has_merged_backedge()), "sanity");
1291   assert(_live_locals.size() == 0, "sanity");
1292 
1293   // entry point has additional predecessor
1294   if (flow()->is_start())  _pred_count++;
1295   assert(flow()->is_start() == (this == outer->start_block()), "");
1296 }
1297 
1298 //-------------------------------init_graph------------------------------------
1299 void Parse::Block::init_graph(Parse* outer) {
1300   // Create the successor list for this parser block.
1301   GrowableArray<ciTypeFlow::Block*>* tfs = flow()->successors();
1302   GrowableArray<ciTypeFlow::Block*>* tfe = flow()->exceptions();
1303   int ns = tfs->length();
1304   int ne = tfe->length();
1305   _num_successors = ns;
1306   _all_successors = ns+ne;
1307   _successors = (ns+ne == 0) ? NULL : NEW_RESOURCE_ARRAY(Block*, ns+ne);
1308   int p = 0;
1309   for (int i = 0; i < ns+ne; i++) {
1310     ciTypeFlow::Block* tf2 = (i < ns) ? tfs->at(i) : tfe->at(i-ns);
1311     Block* block2 = outer->rpo_at(tf2->rpo());
1312     _successors[i] = block2;
1313 
1314     // Accumulate pred info for the other block, too.
1315     // Note: We also need to set _pred_count for exception blocks since they could
1316     // also have normal predecessors (reached without athrow by an explicit jump).
1317     // This also means that next_path_num can be called along exception paths.
1318     block2->_pred_count++;
1319     if (i >= ns) {
1320       block2->_is_handler = true;
1321     }
1322 
1323     #ifdef ASSERT
1324     // A block's successors must be distinguishable by BCI.
1325     // That is, no bytecode is allowed to branch to two different
1326     // clones of the same code location.
1327     for (int j = 0; j < i; j++) {
1328       Block* block1 = _successors[j];
1329       if (block1 == block2)  continue;  // duplicates are OK
1330       assert(block1->start() != block2->start(), "successors have unique bcis");
1331     }
1332     #endif
1333   }
1334 }
1335 
1336 //---------------------------successor_for_bci---------------------------------
1337 Parse::Block* Parse::Block::successor_for_bci(int bci) {
1338   for (int i = 0; i < all_successors(); i++) {
1339     Block* block2 = successor_at(i);
1340     if (block2->start() == bci)  return block2;
1341   }
1342   // We can actually reach here if ciTypeFlow traps out a block
1343   // due to an unloaded class, and concurrently with compilation the
1344   // class is then loaded, so that a later phase of the parser is
1345   // able to see more of the bytecode CFG.  Or, the flow pass and
1346   // the parser can have a minor difference of opinion about executability
1347   // of bytecodes.  For example, "obj.field = null" is executable even
1348   // if the field's type is an unloaded class; the flow pass used to
1349   // make a trap for such code.
1350   return NULL;
1351 }
1352 
1353 
1354 //-----------------------------stack_type_at-----------------------------------
1355 const Type* Parse::Block::stack_type_at(int i) const {
1356   return get_type(flow()->stack_type_at(i));
1357 }
1358 
1359 
1360 //-----------------------------local_type_at-----------------------------------
1361 const Type* Parse::Block::local_type_at(int i) const {
1362   // Make dead locals fall to bottom.
1363   if (_live_locals.size() == 0) {
1364     MethodLivenessResult live_locals = flow()->outer()->method()->liveness_at_bci(start());
1365     // This bitmap can be zero length if we saw a breakpoint.
1366     // In such cases, pretend they are all live.
1367     ((Block*)this)->_live_locals = live_locals;
1368   }
1369   if (_live_locals.size() > 0 && !_live_locals.at(i))
1370     return Type::BOTTOM;
1371 
1372   return get_type(flow()->local_type_at(i));
1373 }
1374 
1375 
1376 #ifndef PRODUCT
1377 
1378 //----------------------------name_for_bc--------------------------------------
1379 // helper method for BytecodeParseHistogram
1380 static const char* name_for_bc(int i) {
1381   return Bytecodes::is_defined(i) ? Bytecodes::name(Bytecodes::cast(i)) : "xxxunusedxxx";
1382 }
1383 
1384 //----------------------------BytecodeParseHistogram------------------------------------
1385 Parse::BytecodeParseHistogram::BytecodeParseHistogram(Parse *p, Compile *c) {
1386   _parser   = p;
1387   _compiler = c;
1388   if( ! _initialized ) { _initialized = true; reset(); }
1389 }
1390 
1391 //----------------------------current_count------------------------------------
1392 int Parse::BytecodeParseHistogram::current_count(BPHType bph_type) {
1393   switch( bph_type ) {
1394   case BPH_transforms: { return _parser->gvn().made_progress(); }
1395   case BPH_values:     { return _parser->gvn().made_new_values(); }
1396   default: { ShouldNotReachHere(); return 0; }
1397   }
1398 }
1399 
1400 //----------------------------initialized--------------------------------------
1401 bool Parse::BytecodeParseHistogram::initialized() { return _initialized; }
1402 
1403 //----------------------------reset--------------------------------------------
1404 void Parse::BytecodeParseHistogram::reset() {
1405   int i = Bytecodes::number_of_codes;
1406   while (i-- > 0) { _bytecodes_parsed[i] = 0; _nodes_constructed[i] = 0; _nodes_transformed[i] = 0; _new_values[i] = 0; }
1407 }
1408 
1409 //----------------------------set_initial_state--------------------------------
1410 // Record info when starting to parse one bytecode
1411 void Parse::BytecodeParseHistogram::set_initial_state( Bytecodes::Code bc ) {
1412   if( PrintParseStatistics && !_parser->is_osr_parse() ) {
1413     _initial_bytecode    = bc;
1414     _initial_node_count  = _compiler->unique();
1415     _initial_transforms  = current_count(BPH_transforms);
1416     _initial_values      = current_count(BPH_values);
1417   }
1418 }
1419 
1420 //----------------------------record_change--------------------------------
1421 // Record results of parsing one bytecode
1422 void Parse::BytecodeParseHistogram::record_change() {
1423   if( PrintParseStatistics && !_parser->is_osr_parse() ) {
1424     ++_bytecodes_parsed[_initial_bytecode];
1425     _nodes_constructed [_initial_bytecode] += (_compiler->unique() - _initial_node_count);
1426     _nodes_transformed [_initial_bytecode] += (current_count(BPH_transforms) - _initial_transforms);
1427     _new_values        [_initial_bytecode] += (current_count(BPH_values)     - _initial_values);
1428   }
1429 }
1430 
1431 
1432 //----------------------------print--------------------------------------------
1433 void Parse::BytecodeParseHistogram::print(float cutoff) {
1434   ResourceMark rm;
1435   // print profile
1436   int total  = 0;
1437   int i      = 0;
1438   for( i = 0; i < Bytecodes::number_of_codes; ++i ) { total += _bytecodes_parsed[i]; }
1439   int abs_sum = 0;
1440   tty->cr();   //0123456789012345678901234567890123456789012345678901234567890123456789
1441   tty->print_cr("Histogram of %d parsed bytecodes:", total);
1442   if( total == 0 ) { return; }
1443   tty->cr();
1444   tty->print_cr("absolute:  count of compiled bytecodes of this type");
1445   tty->print_cr("relative:  percentage contribution to compiled nodes");
1446   tty->print_cr("nodes   :  Average number of nodes constructed per bytecode");
1447   tty->print_cr("rnodes  :  Significance towards total nodes constructed, (nodes*relative)");
1448   tty->print_cr("transforms: Average amount of transform progress per bytecode compiled");
1449   tty->print_cr("values  :  Average number of node values improved per bytecode");
1450   tty->print_cr("name    :  Bytecode name");
1451   tty->cr();
1452   tty->print_cr("  absolute  relative   nodes  rnodes  transforms  values   name");
1453   tty->print_cr("----------------------------------------------------------------------");
1454   while (--i > 0) {
1455     int       abs = _bytecodes_parsed[i];
1456     float     rel = abs * 100.0F / total;
1457     float   nodes = _bytecodes_parsed[i] == 0 ? 0 : (1.0F * _nodes_constructed[i])/_bytecodes_parsed[i];
1458     float  rnodes = _bytecodes_parsed[i] == 0 ? 0 :  rel * nodes;
1459     float  xforms = _bytecodes_parsed[i] == 0 ? 0 : (1.0F * _nodes_transformed[i])/_bytecodes_parsed[i];
1460     float  values = _bytecodes_parsed[i] == 0 ? 0 : (1.0F * _new_values       [i])/_bytecodes_parsed[i];
1461     if (cutoff <= rel) {
1462       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));
1463       abs_sum += abs;
1464     }
1465   }
1466   tty->print_cr("----------------------------------------------------------------------");
1467   float rel_sum = abs_sum * 100.0F / total;
1468   tty->print_cr("%10d  %7.2f%%    (cutoff = %.2f%%)", abs_sum, rel_sum, cutoff);
1469   tty->print_cr("----------------------------------------------------------------------");
1470   tty->cr();
1471 }
1472 #endif
1473 
1474 //----------------------------load_state_from----------------------------------
1475 // Load block/map/sp.  But not do not touch iter/bci.
1476 void Parse::load_state_from(Block* block) {
1477   set_block(block);
1478   // load the block's JVM state:
1479   set_map(block->start_map());
1480   set_sp( block->start_sp());
1481 }
1482 
1483 
1484 //-----------------------------record_state------------------------------------
1485 void Parse::Block::record_state(Parse* p) {
1486   assert(!is_merged(), "can only record state once, on 1st inflow");
1487   assert(start_sp() == p->sp(), "stack pointer must agree with ciTypeFlow");
1488   set_start_map(p->stop());
1489 }
1490 
1491 
1492 //------------------------------do_one_block-----------------------------------
1493 void Parse::do_one_block() {
1494   if (TraceOptoParse) {
1495     Block *b = block();
1496     int ns = b->num_successors();
1497     int nt = b->all_successors();
1498 
1499     tty->print("Parsing block #%d at bci [%d,%d), successors: ",
1500                   block()->rpo(), block()->start(), block()->limit());
1501     for (int i = 0; i < nt; i++) {
1502       tty->print((( i < ns) ? " %d" : " %d(e)"), b->successor_at(i)->rpo());
1503     }
1504     if (b->is_loop_head()) {
1505       tty->print("  lphd");
1506     }
1507     if (b->is_irreducible_loop_entry()) {
1508       tty->print("  irreducible");
1509     }
1510     tty->cr();
1511   }
1512 
1513   assert(block()->is_merged(), "must be merged before being parsed");
1514   block()->mark_parsed();
1515 
1516   // Set iterator to start of block.
1517   iter().reset_to_bci(block()->start());
1518 
1519   CompileLog* log = C->log();
1520 
1521   // Parse bytecodes
1522   while (!stopped() && !failing()) {
1523     iter().next();
1524 
1525     // Learn the current bci from the iterator:
1526     set_parse_bci(iter().cur_bci());
1527 
1528     if (bci() == block()->limit()) {
1529       // Do not walk into the next block until directed by do_all_blocks.
1530       merge(bci());
1531       break;
1532     }
1533     assert(bci() < block()->limit(), "bci still in block");
1534 
1535     if (log != NULL) {
1536       // Output an optional context marker, to help place actions
1537       // that occur during parsing of this BC.  If there is no log
1538       // output until the next context string, this context string
1539       // will be silently ignored.
1540       log->set_context("bc code='%d' bci='%d'", (int)bc(), bci());
1541     }
1542 
1543     if (block()->has_trap_at(bci())) {
1544       // We must respect the flow pass's traps, because it will refuse
1545       // to produce successors for trapping blocks.
1546       int trap_index = block()->flow()->trap_index();
1547       assert(trap_index != 0, "trap index must be valid");
1548       uncommon_trap(trap_index);
1549       break;
1550     }
1551 
1552     NOT_PRODUCT( parse_histogram()->set_initial_state(bc()); );
1553 
1554 #ifdef ASSERT
1555     int pre_bc_sp = sp();
1556     int inputs, depth;
1557     bool have_se = !stopped() && compute_stack_effects(inputs, depth);
1558     assert(!have_se || pre_bc_sp >= inputs, "have enough stack to execute this BC: pre_bc_sp=%d, inputs=%d", pre_bc_sp, inputs);
1559 #endif //ASSERT
1560 
1561     do_one_bytecode();
1562 
1563     assert(!have_se || stopped() || failing() || (sp() - pre_bc_sp) == depth,
1564            "incorrect depth prediction: sp=%d, pre_bc_sp=%d, depth=%d", sp(), pre_bc_sp, depth);
1565 
1566     do_exceptions();
1567 
1568     NOT_PRODUCT( parse_histogram()->record_change(); );
1569 
1570     if (log != NULL)
1571       log->clear_context();  // skip marker if nothing was printed
1572 
1573     // Fall into next bytecode.  Each bytecode normally has 1 sequential
1574     // successor which is typically made ready by visiting this bytecode.
1575     // If the successor has several predecessors, then it is a merge
1576     // point, starts a new basic block, and is handled like other basic blocks.
1577   }
1578 }
1579 
1580 
1581 //------------------------------merge------------------------------------------
1582 void Parse::set_parse_bci(int bci) {
1583   set_bci(bci);
1584   Node_Notes* nn = C->default_node_notes();
1585   if (nn == NULL)  return;
1586 
1587   // Collect debug info for inlined calls unless -XX:-DebugInlinedCalls.
1588   if (!DebugInlinedCalls && depth() > 1) {
1589     return;
1590   }
1591 
1592   // Update the JVMS annotation, if present.
1593   JVMState* jvms = nn->jvms();
1594   if (jvms != NULL && jvms->bci() != bci) {
1595     // Update the JVMS.
1596     jvms = jvms->clone_shallow(C);
1597     jvms->set_bci(bci);
1598     nn->set_jvms(jvms);
1599   }
1600 }
1601 
1602 //------------------------------merge------------------------------------------
1603 // Merge the current mapping into the basic block starting at bci
1604 void Parse::merge(int target_bci) {
1605   Block* target = successor_for_bci(target_bci);
1606   if (target == NULL) { handle_missing_successor(target_bci); return; }
1607   assert(!target->is_ready(), "our arrival must be expected");
1608   int pnum = target->next_path_num();
1609   merge_common(target, pnum);
1610 }
1611 
1612 //-------------------------merge_new_path--------------------------------------
1613 // Merge the current mapping into the basic block, using a new path
1614 void Parse::merge_new_path(int target_bci) {
1615   Block* target = successor_for_bci(target_bci);
1616   if (target == NULL) { handle_missing_successor(target_bci); return; }
1617   assert(!target->is_ready(), "new path into frozen graph");
1618   int pnum = target->add_new_path();
1619   merge_common(target, pnum);
1620 }
1621 
1622 //-------------------------merge_exception-------------------------------------
1623 // Merge the current mapping into the basic block starting at bci
1624 // The ex_oop must be pushed on the stack, unlike throw_to_exit.
1625 void Parse::merge_exception(int target_bci) {
1626 #ifdef ASSERT
1627   if (target_bci < bci()) {
1628     C->set_exception_backedge();
1629   }
1630 #endif
1631   assert(sp() == 1, "must have only the throw exception on the stack");
1632   Block* target = successor_for_bci(target_bci);
1633   if (target == NULL) { handle_missing_successor(target_bci); return; }
1634   assert(target->is_handler(), "exceptions are handled by special blocks");
1635   int pnum = target->add_new_path();
1636   merge_common(target, pnum);
1637 }
1638 
1639 //--------------------handle_missing_successor---------------------------------
1640 void Parse::handle_missing_successor(int target_bci) {
1641 #ifndef PRODUCT
1642   Block* b = block();
1643   int trap_bci = b->flow()->has_trap()? b->flow()->trap_bci(): -1;
1644   tty->print_cr("### Missing successor at bci:%d for block #%d (trap_bci:%d)", target_bci, b->rpo(), trap_bci);
1645 #endif
1646   ShouldNotReachHere();
1647 }
1648 
1649 //--------------------------merge_common---------------------------------------
1650 void Parse::merge_common(Parse::Block* target, int pnum) {
1651   if (TraceOptoParse) {
1652     tty->print("Merging state at block #%d bci:%d", target->rpo(), target->start());
1653   }
1654 
1655   // Zap extra stack slots to top
1656   assert(sp() == target->start_sp(), "");
1657   clean_stack(sp());
1658 
1659   if (!target->is_merged()) {   // No prior mapping at this bci
1660     if (TraceOptoParse) { tty->print(" with empty state");  }
1661 
1662     // If this path is dead, do not bother capturing it as a merge.
1663     // It is "as if" we had 1 fewer predecessors from the beginning.
1664     if (stopped()) {
1665       if (TraceOptoParse)  tty->print_cr(", but path is dead and doesn't count");
1666       return;
1667     }
1668 
1669     // Make a region if we know there are multiple or unpredictable inputs.
1670     // (Also, if this is a plain fall-through, we might see another region,
1671     // which must not be allowed into this block's map.)
1672     if (pnum > PhiNode::Input         // Known multiple inputs.
1673         || target->is_handler()       // These have unpredictable inputs.
1674         || target->is_loop_head()     // Known multiple inputs
1675         || control()->is_Region()) {  // We must hide this guy.
1676 
1677       int current_bci = bci();
1678       set_parse_bci(target->start()); // Set target bci
1679       if (target->is_SEL_head()) {
1680         DEBUG_ONLY( target->mark_merged_backedge(block()); )
1681         if (target->start() == 0) {
1682           // Add loop predicate for the special case when
1683           // there are backbranches to the method entry.
1684           add_empty_predicates();
1685         }
1686       }
1687       // Add a Region to start the new basic block.  Phis will be added
1688       // later lazily.
1689       int edges = target->pred_count();
1690       if (edges < pnum)  edges = pnum;  // might be a new path!
1691       RegionNode *r = new RegionNode(edges+1);
1692       gvn().set_type(r, Type::CONTROL);
1693       record_for_igvn(r);
1694       // zap all inputs to NULL for debugging (done in Node(uint) constructor)
1695       // for (int j = 1; j < edges+1; j++) { r->init_req(j, NULL); }
1696       r->init_req(pnum, control());
1697       set_control(r);
1698       target->copy_irreducible_status_to(r, jvms());
1699       set_parse_bci(current_bci); // Restore bci
1700     }
1701 
1702     // Convert the existing Parser mapping into a mapping at this bci.
1703     store_state_to(target);
1704     assert(target->is_merged(), "do not come here twice");
1705 
1706   } else {                      // Prior mapping at this bci
1707     if (TraceOptoParse) {  tty->print(" with previous state"); }
1708 #ifdef ASSERT
1709     if (target->is_SEL_head()) {
1710       target->mark_merged_backedge(block());
1711     }
1712 #endif
1713     // We must not manufacture more phis if the target is already parsed.
1714     bool nophi = target->is_parsed();
1715 
1716     SafePointNode* newin = map();// Hang on to incoming mapping
1717     Block* save_block = block(); // Hang on to incoming block;
1718     load_state_from(target);    // Get prior mapping
1719 
1720     assert(newin->jvms()->locoff() == jvms()->locoff(), "JVMS layouts agree");
1721     assert(newin->jvms()->stkoff() == jvms()->stkoff(), "JVMS layouts agree");
1722     assert(newin->jvms()->monoff() == jvms()->monoff(), "JVMS layouts agree");
1723     assert(newin->jvms()->endoff() == jvms()->endoff(), "JVMS layouts agree");
1724 
1725     // Iterate over my current mapping and the old mapping.
1726     // Where different, insert Phi functions.
1727     // Use any existing Phi functions.
1728     assert(control()->is_Region(), "must be merging to a region");
1729     RegionNode* r = control()->as_Region();
1730 
1731     // Compute where to merge into
1732     // Merge incoming control path
1733     r->init_req(pnum, newin->control());
1734 
1735     if (pnum == 1) {            // Last merge for this Region?
1736       if (!block()->flow()->is_irreducible_loop_secondary_entry()) {
1737         Node* result = _gvn.transform_no_reclaim(r);
1738         if (r != result && TraceOptoParse) {
1739           tty->print_cr("Block #%d replace %d with %d", block()->rpo(), r->_idx, result->_idx);
1740         }
1741       }
1742       record_for_igvn(r);
1743     }
1744 
1745     // Update all the non-control inputs to map:
1746     assert(TypeFunc::Parms == newin->jvms()->locoff(), "parser map should contain only youngest jvms");
1747     bool check_elide_phi = target->is_SEL_backedge(save_block);
1748     for (uint j = 1; j < newin->req(); j++) {
1749       Node* m = map()->in(j);   // Current state of target.
1750       Node* n = newin->in(j);   // Incoming change to target state.
1751       PhiNode* phi;
1752       if (m->is_Phi() && m->as_Phi()->region() == r)
1753         phi = m->as_Phi();
1754       else
1755         phi = NULL;
1756       if (m != n) {             // Different; must merge
1757         switch (j) {
1758         // Frame pointer and Return Address never changes
1759         case TypeFunc::FramePtr:// Drop m, use the original value
1760         case TypeFunc::ReturnAdr:
1761           break;
1762         case TypeFunc::Memory:  // Merge inputs to the MergeMem node
1763           assert(phi == NULL, "the merge contains phis, not vice versa");
1764           merge_memory_edges(n->as_MergeMem(), pnum, nophi);
1765           continue;
1766         default:                // All normal stuff
1767           if (phi == NULL) {
1768             const JVMState* jvms = map()->jvms();
1769             if (EliminateNestedLocks &&
1770                 jvms->is_mon(j) && jvms->is_monitor_box(j)) {
1771               // BoxLock nodes are not commoning.
1772               // Use old BoxLock node as merged box.
1773               assert(newin->jvms()->is_monitor_box(j), "sanity");
1774               // This assert also tests that nodes are BoxLock.
1775               assert(BoxLockNode::same_slot(n, m), "sanity");
1776               C->gvn_replace_by(n, m);
1777             } else if (!check_elide_phi || !target->can_elide_SEL_phi(j)) {
1778               phi = ensure_phi(j, nophi);
1779             }
1780           }
1781           break;
1782         }
1783       }
1784       // At this point, n might be top if:
1785       //  - there is no phi (because TypeFlow detected a conflict), or
1786       //  - the corresponding control edges is top (a dead incoming path)
1787       // It is a bug if we create a phi which sees a garbage value on a live path.
1788 
1789       if (phi != NULL) {
1790         assert(n != top() || r->in(pnum) == top(), "live value must not be garbage");
1791         assert(phi->region() == r, "");
1792         phi->set_req(pnum, n);  // Then add 'n' to the merge
1793         if (pnum == PhiNode::Input) {
1794           // Last merge for this Phi.
1795           // So far, Phis have had a reasonable type from ciTypeFlow.
1796           // Now _gvn will join that with the meet of current inputs.
1797           // BOTTOM is never permissible here, 'cause pessimistically
1798           // Phis of pointers cannot lose the basic pointer type.
1799           debug_only(const Type* bt1 = phi->bottom_type());
1800           assert(bt1 != Type::BOTTOM, "should not be building conflict phis");
1801           map()->set_req(j, _gvn.transform_no_reclaim(phi));
1802           debug_only(const Type* bt2 = phi->bottom_type());
1803           assert(bt2->higher_equal_speculative(bt1), "must be consistent with type-flow");
1804           record_for_igvn(phi);
1805         }
1806       }
1807     } // End of for all values to be merged
1808 
1809     if (pnum == PhiNode::Input &&
1810         !r->in(0)) {         // The occasional useless Region
1811       assert(control() == r, "");
1812       set_control(r->nonnull_req());
1813     }
1814 
1815     map()->merge_replaced_nodes_with(newin);
1816 
1817     // newin has been subsumed into the lazy merge, and is now dead.
1818     set_block(save_block);
1819 
1820     stop();                     // done with this guy, for now
1821   }
1822 
1823   if (TraceOptoParse) {
1824     tty->print_cr(" on path %d", pnum);
1825   }
1826 
1827   // Done with this parser state.
1828   assert(stopped(), "");
1829 }
1830 
1831 
1832 //--------------------------merge_memory_edges---------------------------------
1833 void Parse::merge_memory_edges(MergeMemNode* n, int pnum, bool nophi) {
1834   // (nophi means we must not create phis, because we already parsed here)
1835   assert(n != NULL, "");
1836   // Merge the inputs to the MergeMems
1837   MergeMemNode* m = merged_memory();
1838 
1839   assert(control()->is_Region(), "must be merging to a region");
1840   RegionNode* r = control()->as_Region();
1841 
1842   PhiNode* base = NULL;
1843   MergeMemNode* remerge = NULL;
1844   for (MergeMemStream mms(m, n); mms.next_non_empty2(); ) {
1845     Node *p = mms.force_memory();
1846     Node *q = mms.memory2();
1847     if (mms.is_empty() && nophi) {
1848       // Trouble:  No new splits allowed after a loop body is parsed.
1849       // Instead, wire the new split into a MergeMem on the backedge.
1850       // The optimizer will sort it out, slicing the phi.
1851       if (remerge == NULL) {
1852         guarantee(base != NULL, "");
1853         assert(base->in(0) != NULL, "should not be xformed away");
1854         remerge = MergeMemNode::make(base->in(pnum));
1855         gvn().set_type(remerge, Type::MEMORY);
1856         base->set_req(pnum, remerge);
1857       }
1858       remerge->set_memory_at(mms.alias_idx(), q);
1859       continue;
1860     }
1861     assert(!q->is_MergeMem(), "");
1862     PhiNode* phi;
1863     if (p != q) {
1864       phi = ensure_memory_phi(mms.alias_idx(), nophi);
1865     } else {
1866       if (p->is_Phi() && p->as_Phi()->region() == r)
1867         phi = p->as_Phi();
1868       else
1869         phi = NULL;
1870     }
1871     // Insert q into local phi
1872     if (phi != NULL) {
1873       assert(phi->region() == r, "");
1874       p = phi;
1875       phi->set_req(pnum, q);
1876       if (mms.at_base_memory()) {
1877         base = phi;  // delay transforming it
1878       } else if (pnum == 1) {
1879         record_for_igvn(phi);
1880         p = _gvn.transform_no_reclaim(phi);
1881       }
1882       mms.set_memory(p);// store back through the iterator
1883     }
1884   }
1885   // Transform base last, in case we must fiddle with remerging.
1886   if (base != NULL && pnum == 1) {
1887     record_for_igvn(base);
1888     m->set_base_memory( _gvn.transform_no_reclaim(base) );
1889   }
1890 }
1891 
1892 
1893 //------------------------ensure_phis_everywhere-------------------------------
1894 void Parse::ensure_phis_everywhere() {
1895   ensure_phi(TypeFunc::I_O);
1896 
1897   // Ensure a phi on all currently known memories.
1898   for (MergeMemStream mms(merged_memory()); mms.next_non_empty(); ) {
1899     ensure_memory_phi(mms.alias_idx());
1900     debug_only(mms.set_memory());  // keep the iterator happy
1901   }
1902 
1903   // Note:  This is our only chance to create phis for memory slices.
1904   // If we miss a slice that crops up later, it will have to be
1905   // merged into the base-memory phi that we are building here.
1906   // Later, the optimizer will comb out the knot, and build separate
1907   // phi-loops for each memory slice that matters.
1908 
1909   // Monitors must nest nicely and not get confused amongst themselves.
1910   // Phi-ify everything up to the monitors, though.
1911   uint monoff = map()->jvms()->monoff();
1912   uint nof_monitors = map()->jvms()->nof_monitors();
1913 
1914   assert(TypeFunc::Parms == map()->jvms()->locoff(), "parser map should contain only youngest jvms");
1915   bool check_elide_phi = block()->is_SEL_head();
1916   for (uint i = TypeFunc::Parms; i < monoff; i++) {
1917     if (!check_elide_phi || !block()->can_elide_SEL_phi(i)) {
1918       ensure_phi(i);
1919     }
1920   }
1921 
1922   // Even monitors need Phis, though they are well-structured.
1923   // This is true for OSR methods, and also for the rare cases where
1924   // a monitor object is the subject of a replace_in_map operation.
1925   // See bugs 4426707 and 5043395.
1926   for (uint m = 0; m < nof_monitors; m++) {
1927     ensure_phi(map()->jvms()->monitor_obj_offset(m));
1928   }
1929 }
1930 
1931 
1932 //-----------------------------add_new_path------------------------------------
1933 // Add a previously unaccounted predecessor to this block.
1934 int Parse::Block::add_new_path() {
1935   // If there is no map, return the lowest unused path number.
1936   if (!is_merged())  return pred_count()+1;  // there will be a map shortly
1937 
1938   SafePointNode* map = start_map();
1939   if (!map->control()->is_Region())
1940     return pred_count()+1;  // there may be a region some day
1941   RegionNode* r = map->control()->as_Region();
1942 
1943   // Add new path to the region.
1944   uint pnum = r->req();
1945   r->add_req(NULL);
1946 
1947   for (uint i = 1; i < map->req(); i++) {
1948     Node* n = map->in(i);
1949     if (i == TypeFunc::Memory) {
1950       // Ensure a phi on all currently known memories.
1951       for (MergeMemStream mms(n->as_MergeMem()); mms.next_non_empty(); ) {
1952         Node* phi = mms.memory();
1953         if (phi->is_Phi() && phi->as_Phi()->region() == r) {
1954           assert(phi->req() == pnum, "must be same size as region");
1955           phi->add_req(NULL);
1956         }
1957       }
1958     } else {
1959       if (n->is_Phi() && n->as_Phi()->region() == r) {
1960         assert(n->req() == pnum, "must be same size as region");
1961         n->add_req(NULL);
1962       }
1963     }
1964   }
1965 
1966   return pnum;
1967 }
1968 
1969 //------------------------------ensure_phi-------------------------------------
1970 // Turn the idx'th entry of the current map into a Phi
1971 PhiNode *Parse::ensure_phi(int idx, bool nocreate) {
1972   SafePointNode* map = this->map();
1973   Node* region = map->control();
1974   assert(region->is_Region(), "");
1975 
1976   Node* o = map->in(idx);
1977   assert(o != NULL, "");
1978 
1979   if (o == top())  return NULL; // TOP always merges into TOP
1980 
1981   if (o->is_Phi() && o->as_Phi()->region() == region) {
1982     return o->as_Phi();
1983   }
1984 
1985   // Now use a Phi here for merging
1986   assert(!nocreate, "Cannot build a phi for a block already parsed.");
1987   const JVMState* jvms = map->jvms();
1988   const Type* t = NULL;
1989   if (jvms->is_loc(idx)) {
1990     t = block()->local_type_at(idx - jvms->locoff());
1991   } else if (jvms->is_stk(idx)) {
1992     t = block()->stack_type_at(idx - jvms->stkoff());
1993   } else if (jvms->is_mon(idx)) {
1994     assert(!jvms->is_monitor_box(idx), "no phis for boxes");
1995     t = TypeInstPtr::BOTTOM; // this is sufficient for a lock object
1996   } else if ((uint)idx < TypeFunc::Parms) {
1997     t = o->bottom_type();  // Type::RETURN_ADDRESS or such-like.
1998   } else {
1999     assert(false, "no type information for this phi");
2000   }
2001 
2002   // If the type falls to bottom, then this must be a local that
2003   // is mixing ints and oops or some such.  Forcing it to top
2004   // makes it go dead.
2005   if (t == Type::BOTTOM) {
2006     map->set_req(idx, top());
2007     return NULL;
2008   }
2009 
2010   // Do not create phis for top either.
2011   // A top on a non-null control flow must be an unused even after the.phi.
2012   if (t == Type::TOP || t == Type::HALF) {
2013     map->set_req(idx, top());
2014     return NULL;
2015   }
2016 
2017   PhiNode* phi = PhiNode::make(region, o, t);
2018   gvn().set_type(phi, t);
2019   if (C->do_escape_analysis()) record_for_igvn(phi);
2020   map->set_req(idx, phi);
2021   return phi;
2022 }
2023 
2024 //--------------------------ensure_memory_phi----------------------------------
2025 // Turn the idx'th slice of the current memory into a Phi
2026 PhiNode *Parse::ensure_memory_phi(int idx, bool nocreate) {
2027   MergeMemNode* mem = merged_memory();
2028   Node* region = control();
2029   assert(region->is_Region(), "");
2030 
2031   Node *o = (idx == Compile::AliasIdxBot)? mem->base_memory(): mem->memory_at(idx);
2032   assert(o != NULL && o != top(), "");
2033 
2034   PhiNode* phi;
2035   if (o->is_Phi() && o->as_Phi()->region() == region) {
2036     phi = o->as_Phi();
2037     if (phi == mem->base_memory() && idx >= Compile::AliasIdxRaw) {
2038       // clone the shared base memory phi to make a new memory split
2039       assert(!nocreate, "Cannot build a phi for a block already parsed.");
2040       const Type* t = phi->bottom_type();
2041       const TypePtr* adr_type = C->get_adr_type(idx);
2042       phi = phi->slice_memory(adr_type);
2043       gvn().set_type(phi, t);
2044     }
2045     return phi;
2046   }
2047 
2048   // Now use a Phi here for merging
2049   assert(!nocreate, "Cannot build a phi for a block already parsed.");
2050   const Type* t = o->bottom_type();
2051   const TypePtr* adr_type = C->get_adr_type(idx);
2052   phi = PhiNode::make(region, o, t, adr_type);
2053   gvn().set_type(phi, t);
2054   if (idx == Compile::AliasIdxBot)
2055     mem->set_base_memory(phi);
2056   else
2057     mem->set_memory_at(idx, phi);
2058   return phi;
2059 }
2060 
2061 //------------------------------call_register_finalizer-----------------------
2062 // Check the klass of the receiver and call register_finalizer if the
2063 // class need finalization.
2064 void Parse::call_register_finalizer() {
2065   Node* receiver = local(0);
2066   assert(receiver != NULL && receiver->bottom_type()->isa_instptr() != NULL,
2067          "must have non-null instance type");
2068 
2069   const TypeInstPtr *tinst = receiver->bottom_type()->isa_instptr();
2070   if (tinst != NULL && tinst->is_loaded() && !tinst->klass_is_exact()) {
2071     // The type isn't known exactly so see if CHA tells us anything.
2072     ciInstanceKlass* ik = tinst->instance_klass();
2073     if (!Dependencies::has_finalizable_subclass(ik)) {
2074       // No finalizable subclasses so skip the dynamic check.
2075       C->dependencies()->assert_has_no_finalizable_subclasses(ik);
2076       return;
2077     }
2078   }
2079 
2080   // Insert a dynamic test for whether the instance needs
2081   // finalization.  In general this will fold up since the concrete
2082   // class is often visible so the access flags are constant.
2083   Node* klass_addr = basic_plus_adr( receiver, receiver, oopDesc::klass_offset_in_bytes() );
2084   Node* klass = _gvn.transform(LoadKlassNode::make(_gvn, NULL, immutable_memory(), klass_addr, TypeInstPtr::KLASS));
2085 
2086   Node* access_flags_addr = basic_plus_adr(klass, klass, in_bytes(Klass::access_flags_offset()));
2087   Node* access_flags = make_load(NULL, access_flags_addr, TypeInt::INT, T_INT, MemNode::unordered);
2088 
2089   Node* mask  = _gvn.transform(new AndINode(access_flags, intcon(JVM_ACC_HAS_FINALIZER)));
2090   Node* check = _gvn.transform(new CmpINode(mask, intcon(0)));
2091   Node* test  = _gvn.transform(new BoolNode(check, BoolTest::ne));
2092 
2093   IfNode* iff = create_and_map_if(control(), test, PROB_MAX, COUNT_UNKNOWN);
2094 
2095   RegionNode* result_rgn = new RegionNode(3);
2096   record_for_igvn(result_rgn);
2097 
2098   Node *skip_register = _gvn.transform(new IfFalseNode(iff));
2099   result_rgn->init_req(1, skip_register);
2100 
2101   Node *needs_register = _gvn.transform(new IfTrueNode(iff));
2102   set_control(needs_register);
2103   if (stopped()) {
2104     // There is no slow path.
2105     result_rgn->init_req(2, top());
2106   } else {
2107     Node *call = make_runtime_call(RC_NO_LEAF,
2108                                    OptoRuntime::register_finalizer_Type(),
2109                                    OptoRuntime::register_finalizer_Java(),
2110                                    NULL, TypePtr::BOTTOM,
2111                                    receiver);
2112     make_slow_call_ex(call, env()->Throwable_klass(), true);
2113 
2114     Node* fast_io  = call->in(TypeFunc::I_O);
2115     Node* fast_mem = call->in(TypeFunc::Memory);
2116     // These two phis are pre-filled with copies of of the fast IO and Memory
2117     Node* io_phi   = PhiNode::make(result_rgn, fast_io,  Type::ABIO);
2118     Node* mem_phi  = PhiNode::make(result_rgn, fast_mem, Type::MEMORY, TypePtr::BOTTOM);
2119 
2120     result_rgn->init_req(2, control());
2121     io_phi    ->init_req(2, i_o());
2122     mem_phi   ->init_req(2, reset_memory());
2123 
2124     set_all_memory( _gvn.transform(mem_phi) );
2125     set_i_o(        _gvn.transform(io_phi) );
2126   }
2127 
2128   set_control( _gvn.transform(result_rgn) );
2129 }
2130 
2131 // Add check to deoptimize once holder klass is fully initialized.
2132 void Parse::clinit_deopt() {
2133   assert(C->has_method(), "only for normal compilations");
2134   assert(depth() == 1, "only for main compiled method");
2135   assert(is_normal_parse(), "no barrier needed on osr entry");
2136   assert(!method()->holder()->is_not_initialized(), "initialization should have been started");
2137 
2138   set_parse_bci(0);
2139 
2140   Node* holder = makecon(TypeKlassPtr::make(method()->holder(), Type::trust_interfaces));
2141   guard_klass_being_initialized(holder);
2142 }
2143 
2144 // Add check to deoptimize if RTM state is not ProfileRTM
2145 void Parse::rtm_deopt() {
2146 #if INCLUDE_RTM_OPT
2147   if (C->profile_rtm()) {
2148     assert(C->has_method(), "only for normal compilations");
2149     assert(!C->method()->method_data()->is_empty(), "MDO is needed to record RTM state");
2150     assert(depth() == 1, "generate check only for main compiled method");
2151 
2152     // Set starting bci for uncommon trap.
2153     set_parse_bci(is_osr_parse() ? osr_bci() : 0);
2154 
2155     // Load the rtm_state from the MethodData.
2156     const TypePtr* adr_type = TypeMetadataPtr::make(C->method()->method_data());
2157     Node* mdo = makecon(adr_type);
2158     int offset = MethodData::rtm_state_offset_in_bytes();
2159     Node* adr_node = basic_plus_adr(mdo, mdo, offset);
2160     Node* rtm_state = make_load(control(), adr_node, TypeInt::INT, T_INT, adr_type, MemNode::unordered);
2161 
2162     // Separate Load from Cmp by Opaque.
2163     // In expand_macro_nodes() it will be replaced either
2164     // with this load when there are locks in the code
2165     // or with ProfileRTM (cmp->in(2)) otherwise so that
2166     // the check will fold.
2167     Node* profile_state = makecon(TypeInt::make(ProfileRTM));
2168     Node* opq   = _gvn.transform( new Opaque3Node(C, rtm_state, Opaque3Node::RTM_OPT) );
2169     Node* chk   = _gvn.transform( new CmpINode(opq, profile_state) );
2170     Node* tst   = _gvn.transform( new BoolNode(chk, BoolTest::eq) );
2171     // Branch to failure if state was changed
2172     { BuildCutout unless(this, tst, PROB_ALWAYS);
2173       uncommon_trap(Deoptimization::Reason_rtm_state_change,
2174                     Deoptimization::Action_make_not_entrant);
2175     }
2176   }
2177 #endif
2178 }
2179 
2180 //------------------------------return_current---------------------------------
2181 // Append current _map to _exit_return
2182 void Parse::return_current(Node* value) {
2183   if (RegisterFinalizersAtInit &&
2184       method()->intrinsic_id() == vmIntrinsics::_Object_init) {
2185     call_register_finalizer();
2186   }
2187 
2188   // Do not set_parse_bci, so that return goo is credited to the return insn.
2189   set_bci(InvocationEntryBci);
2190   if (method()->is_synchronized() && GenerateSynchronizationCode) {
2191     shared_unlock(_synch_lock->box_node(), _synch_lock->obj_node());
2192   }
2193   if (C->env()->dtrace_method_probes()) {
2194     make_dtrace_method_exit(method());
2195   }
2196   SafePointNode* exit_return = _exits.map();
2197   exit_return->in( TypeFunc::Control  )->add_req( control() );
2198   exit_return->in( TypeFunc::I_O      )->add_req( i_o    () );
2199   Node *mem = exit_return->in( TypeFunc::Memory   );
2200   for (MergeMemStream mms(mem->as_MergeMem(), merged_memory()); mms.next_non_empty2(); ) {
2201     if (mms.is_empty()) {
2202       // get a copy of the base memory, and patch just this one input
2203       const TypePtr* adr_type = mms.adr_type(C);
2204       Node* phi = mms.force_memory()->as_Phi()->slice_memory(adr_type);
2205       assert(phi->as_Phi()->region() == mms.base_memory()->in(0), "");
2206       gvn().set_type_bottom(phi);
2207       phi->del_req(phi->req()-1);  // prepare to re-patch
2208       mms.set_memory(phi);
2209     }
2210     mms.memory()->add_req(mms.memory2());
2211   }
2212 
2213   // frame pointer is always same, already captured
2214   if (value != NULL) {
2215     // If returning oops to an interface-return, there is a silent free
2216     // cast from oop to interface allowed by the Verifier.  Make it explicit
2217     // here.
2218     Node* phi = _exits.argument(0);
2219     phi->add_req(value);
2220   }
2221 
2222   if (_first_return) {
2223     _exits.map()->transfer_replaced_nodes_from(map(), _new_idx);
2224     _first_return = false;
2225   } else {
2226     _exits.map()->merge_replaced_nodes_with(map());
2227   }
2228 
2229   stop_and_kill_map();          // This CFG path dies here
2230 }
2231 
2232 
2233 //------------------------------add_safepoint----------------------------------
2234 void Parse::add_safepoint() {
2235   uint parms = TypeFunc::Parms+1;
2236 
2237   // Clear out dead values from the debug info.
2238   kill_dead_locals();
2239 
2240   // Clone the JVM State
2241   SafePointNode *sfpnt = new SafePointNode(parms, NULL);
2242 
2243   // Capture memory state BEFORE a SafePoint.  Since we can block at a
2244   // SafePoint we need our GC state to be safe; i.e. we need all our current
2245   // write barriers (card marks) to not float down after the SafePoint so we
2246   // must read raw memory.  Likewise we need all oop stores to match the card
2247   // marks.  If deopt can happen, we need ALL stores (we need the correct JVM
2248   // state on a deopt).
2249 
2250   // We do not need to WRITE the memory state after a SafePoint.  The control
2251   // edge will keep card-marks and oop-stores from floating up from below a
2252   // SafePoint and our true dependency added here will keep them from floating
2253   // down below a SafePoint.
2254 
2255   // Clone the current memory state
2256   Node* mem = MergeMemNode::make(map()->memory());
2257 
2258   mem = _gvn.transform(mem);
2259 
2260   // Pass control through the safepoint
2261   sfpnt->init_req(TypeFunc::Control  , control());
2262   // Fix edges normally used by a call
2263   sfpnt->init_req(TypeFunc::I_O      , top() );
2264   sfpnt->init_req(TypeFunc::Memory   , mem   );
2265   sfpnt->init_req(TypeFunc::ReturnAdr, top() );
2266   sfpnt->init_req(TypeFunc::FramePtr , top() );
2267 
2268   // Create a node for the polling address
2269   Node *polladr;
2270   Node *thread = _gvn.transform(new ThreadLocalNode());
2271   Node *polling_page_load_addr = _gvn.transform(basic_plus_adr(top(), thread, in_bytes(JavaThread::polling_page_offset())));
2272   polladr = make_load(control(), polling_page_load_addr, TypeRawPtr::BOTTOM, T_ADDRESS, Compile::AliasIdxRaw, MemNode::unordered);
2273   sfpnt->init_req(TypeFunc::Parms+0, _gvn.transform(polladr));
2274 
2275   // Fix up the JVM State edges
2276   add_safepoint_edges(sfpnt);
2277   Node *transformed_sfpnt = _gvn.transform(sfpnt);
2278   set_control(transformed_sfpnt);
2279 
2280   // Provide an edge from root to safepoint.  This makes the safepoint
2281   // appear useful until the parse has completed.
2282   if (transformed_sfpnt->is_SafePoint()) {
2283     assert(C->root() != NULL, "Expect parse is still valid");
2284     C->root()->add_prec(transformed_sfpnt);
2285   }
2286 }
2287 
2288 #ifndef PRODUCT
2289 //------------------------show_parse_info--------------------------------------
2290 void Parse::show_parse_info() {
2291   InlineTree* ilt = NULL;
2292   if (C->ilt() != NULL) {
2293     JVMState* caller_jvms = is_osr_parse() ? caller()->caller() : caller();
2294     ilt = InlineTree::find_subtree_from_root(C->ilt(), caller_jvms, method());
2295   }
2296   if (PrintCompilation && Verbose) {
2297     if (depth() == 1) {
2298       if( ilt->count_inlines() ) {
2299         tty->print("    __inlined %d (%d bytes)", ilt->count_inlines(),
2300                      ilt->count_inline_bcs());
2301         tty->cr();
2302       }
2303     } else {
2304       if (method()->is_synchronized())         tty->print("s");
2305       if (method()->has_exception_handlers())  tty->print("!");
2306       // Check this is not the final compiled version
2307       if (C->trap_can_recompile()) {
2308         tty->print("-");
2309       } else {
2310         tty->print(" ");
2311       }
2312       method()->print_short_name();
2313       if (is_osr_parse()) {
2314         tty->print(" @ %d", osr_bci());
2315       }
2316       tty->print(" (%d bytes)",method()->code_size());
2317       if (ilt->count_inlines()) {
2318         tty->print(" __inlined %d (%d bytes)", ilt->count_inlines(),
2319                    ilt->count_inline_bcs());
2320       }
2321       tty->cr();
2322     }
2323   }
2324   if (PrintOpto && (depth() == 1 || PrintOptoInlining)) {
2325     // Print that we succeeded; suppress this message on the first osr parse.
2326 
2327     if (method()->is_synchronized())         tty->print("s");
2328     if (method()->has_exception_handlers())  tty->print("!");
2329     // Check this is not the final compiled version
2330     if (C->trap_can_recompile() && depth() == 1) {
2331       tty->print("-");
2332     } else {
2333       tty->print(" ");
2334     }
2335     if( depth() != 1 ) { tty->print("   "); }  // missing compile count
2336     for (int i = 1; i < depth(); ++i) { tty->print("  "); }
2337     method()->print_short_name();
2338     if (is_osr_parse()) {
2339       tty->print(" @ %d", osr_bci());
2340     }
2341     if (ilt->caller_bci() != -1) {
2342       tty->print(" @ %d", ilt->caller_bci());
2343     }
2344     tty->print(" (%d bytes)",method()->code_size());
2345     if (ilt->count_inlines()) {
2346       tty->print(" __inlined %d (%d bytes)", ilt->count_inlines(),
2347                  ilt->count_inline_bcs());
2348     }
2349     tty->cr();
2350   }
2351 }
2352 
2353 
2354 //------------------------------dump-------------------------------------------
2355 // Dump information associated with the bytecodes of current _method
2356 void Parse::dump() {
2357   if( method() != NULL ) {
2358     // Iterate over bytecodes
2359     ciBytecodeStream iter(method());
2360     for( Bytecodes::Code bc = iter.next(); bc != ciBytecodeStream::EOBC() ; bc = iter.next() ) {
2361       dump_bci( iter.cur_bci() );
2362       tty->cr();
2363     }
2364   }
2365 }
2366 
2367 // Dump information associated with a byte code index, 'bci'
2368 void Parse::dump_bci(int bci) {
2369   // Output info on merge-points, cloning, and within _jsr..._ret
2370   // NYI
2371   tty->print(" bci:%d", bci);
2372 }
2373 
2374 #endif