Mercurial > jdk8-mips64-public > hotspot / file revision

 /*

  * Copyright (c) 1997, 2016, Oracle and/or its affiliates. All rights reserved.

  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

  *

  * This code is free software; you can redistribute it and/or modify it

  * under the terms of the GNU General Public License version 2 only, as

  * published by the Free Software Foundation.

  *

  * This code is distributed in the hope that it will be useful, but WITHOUT

  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

  * version 2 for more details (a copy is included in the LICENSE file that

  * accompanied this code).

  *

  * You should have received a copy of the GNU General Public License version

  * 2 along with this work; if not, write to the Free Software Foundation,

  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

  *

  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

  * or visit www.oracle.com if you need additional information or have any

  * questions.

  *

  */

 #include "precompiled.hpp"

 #include "compiler/compileLog.hpp"

 #include "interpreter/linkResolver.hpp"

 #include "oops/method.hpp"

 #include "opto/addnode.hpp"

 #include "opto/c2compiler.hpp"

 #include "opto/idealGraphPrinter.hpp"

 #include "opto/locknode.hpp"

 #include "opto/memnode.hpp"

 #include "opto/parse.hpp"

 #include "opto/rootnode.hpp"

 #include "opto/runtime.hpp"

 #include "runtime/arguments.hpp"

 #include "runtime/handles.inline.hpp"

 #include "runtime/sharedRuntime.hpp"

 #include "utilities/copy.hpp"

 // Static array so we can figure out which bytecodes stop us from compiling

 // the most. Some of the non-static variables are needed in bytecodeInfo.cpp

 // and eventually should be encapsulated in a proper class (gri 8/18/98).

 int nodes_created              = 0;

 int methods_parsed             = 0;

 int methods_seen               = 0;

 int blocks_parsed              = 0;

 int blocks_seen                = 0;

 int explicit_null_checks_inserted = 0;

 int explicit_null_checks_elided   = 0;

 int all_null_checks_found         = 0, implicit_null_checks              = 0;

 int implicit_null_throws          = 0;

 int reclaim_idx  = 0;

 int reclaim_in   = 0;

 int reclaim_node = 0;

 #ifndef PRODUCT

 bool Parse::BytecodeParseHistogram::_initialized = false;

 uint Parse::BytecodeParseHistogram::_bytecodes_parsed [Bytecodes::number_of_codes];

 uint Parse::BytecodeParseHistogram::_nodes_constructed[Bytecodes::number_of_codes];

 uint Parse::BytecodeParseHistogram::_nodes_transformed[Bytecodes::number_of_codes];

 uint Parse::BytecodeParseHistogram::_new_values       [Bytecodes::number_of_codes];

 #endif

 //------------------------------print_statistics-------------------------------

 #ifndef PRODUCT

 void Parse::print_statistics() {

   tty->print_cr("--- Compiler Statistics ---");

   tty->print("Methods seen: %d  Methods parsed: %d", methods_seen, methods_parsed);

   tty->print("  Nodes created: %d", nodes_created);

   tty->cr();

   if (methods_seen != methods_parsed)

     tty->print_cr("Reasons for parse failures (NOT cumulative):");

   tty->print_cr("Blocks parsed: %d  Blocks seen: %d", blocks_parsed, blocks_seen);

   if( explicit_null_checks_inserted )

     tty->print_cr("%d original NULL checks - %d elided (%2d%%); optimizer leaves %d,", explicit_null_checks_inserted, explicit_null_checks_elided, (100*explicit_null_checks_elided)/explicit_null_checks_inserted, all_null_checks_found);

   if( all_null_checks_found )

     tty->print_cr("%d made implicit (%2d%%)", implicit_null_checks,

                   (100*implicit_null_checks)/all_null_checks_found);

   if( implicit_null_throws )

     tty->print_cr("%d implicit null exceptions at runtime",

                   implicit_null_throws);

   if( PrintParseStatistics && BytecodeParseHistogram::initialized() ) {

     BytecodeParseHistogram::print();

   }

 }

 #endif

 //------------------------------ON STACK REPLACEMENT---------------------------

 // Construct a node which can be used to get incoming state for

 // on stack replacement.

 Node *Parse::fetch_interpreter_state(int index,

                                      BasicType bt,

                                      Node *local_addrs,

                                      Node *local_addrs_base) {

   Node *mem = memory(Compile::AliasIdxRaw);

   Node *adr = basic_plus_adr( local_addrs_base, local_addrs, -index*wordSize );

   Node *ctl = control();

   // Very similar to LoadNode::make, except we handle un-aligned longs and

   // doubles on Sparc.  Intel can handle them just fine directly.

   Node *l = NULL;

   switch (bt) {                // Signature is flattened

   case T_INT:     l = new (C) LoadINode(ctl, mem, adr, TypeRawPtr::BOTTOM, TypeInt::INT,        MemNode::unordered); break;

   case T_FLOAT:   l = new (C) LoadFNode(ctl, mem, adr, TypeRawPtr::BOTTOM, Type::FLOAT,         MemNode::unordered); break;

   case T_ADDRESS: l = new (C) LoadPNode(ctl, mem, adr, TypeRawPtr::BOTTOM, TypeRawPtr::BOTTOM,  MemNode::unordered); break;

   case T_OBJECT:  l = new (C) LoadPNode(ctl, mem, adr, TypeRawPtr::BOTTOM, TypeInstPtr::BOTTOM, MemNode::unordered); break;

   case T_LONG:

   case T_DOUBLE: {

     // Since arguments are in reverse order, the argument address 'adr'

     // refers to the back half of the long/double.  Recompute adr.

     adr = basic_plus_adr(local_addrs_base, local_addrs, -(index+1)*wordSize);

     if (Matcher::misaligned_doubles_ok) {

       l = (bt == T_DOUBLE)

         ? (Node*)new (C) LoadDNode(ctl, mem, adr, TypeRawPtr::BOTTOM, Type::DOUBLE, MemNode::unordered)

         : (Node*)new (C) LoadLNode(ctl, mem, adr, TypeRawPtr::BOTTOM, TypeLong::LONG, MemNode::unordered);

     } else {

       l = (bt == T_DOUBLE)

         ? (Node*)new (C) LoadD_unalignedNode(ctl, mem, adr, TypeRawPtr::BOTTOM, MemNode::unordered)

         : (Node*)new (C) LoadL_unalignedNode(ctl, mem, adr, TypeRawPtr::BOTTOM, MemNode::unordered);

     }

     break;

   }

   default: ShouldNotReachHere();

   }

   return _gvn.transform(l);

 }

 // Helper routine to prevent the interpreter from handing

 // unexpected typestate to an OSR method.

 // The Node l is a value newly dug out of the interpreter frame.

 // The type is the type predicted by ciTypeFlow.  Note that it is

 // not a general type, but can only come from Type::get_typeflow_type.

 // The safepoint is a map which will feed an uncommon trap.

 Node* Parse::check_interpreter_type(Node* l, const Type* type,

                                     SafePointNode* &bad_type_exit) {

   const TypeOopPtr* tp = type->isa_oopptr();

   // TypeFlow may assert null-ness if a type appears unloaded.

   if (type == TypePtr::NULL_PTR ||

       (tp != NULL && !tp->klass()->is_loaded())) {

     // Value must be null, not a real oop.

     Node* chk = _gvn.transform( new (C) CmpPNode(l, null()) );

     Node* tst = _gvn.transform( new (C) BoolNode(chk, BoolTest::eq) );

     IfNode* iff = create_and_map_if(control(), tst, PROB_MAX, COUNT_UNKNOWN);

     set_control(_gvn.transform( new (C) IfTrueNode(iff) ));

     Node* bad_type = _gvn.transform( new (C) IfFalseNode(iff) );

     bad_type_exit->control()->add_req(bad_type);

     l = null();

   }

   // Typeflow can also cut off paths from the CFG, based on

   // types which appear unloaded, or call sites which appear unlinked.

   // When paths are cut off, values at later merge points can rise

   // toward more specific classes.  Make sure these specific classes

   // are still in effect.

   if (tp != NULL && tp->klass() != C->env()->Object_klass()) {

     // TypeFlow asserted a specific object type.  Value must have that type.

     Node* bad_type_ctrl = NULL;

     l = gen_checkcast(l, makecon(TypeKlassPtr::make(tp->klass())), &bad_type_ctrl);

     bad_type_exit->control()->add_req(bad_type_ctrl);

   }

   BasicType bt_l = _gvn.type(l)->basic_type();

   BasicType bt_t = type->basic_type();

   assert(_gvn.type(l)->higher_equal(type), "must constrain OSR typestate");

   return l;

 }

 // Helper routine which sets up elements of the initial parser map when

 // performing a parse for on stack replacement.  Add values into map.

 // The only parameter contains the address of a interpreter arguments.

 void Parse::load_interpreter_state(Node* osr_buf) {

   int index;

   int max_locals = jvms()->loc_size();

   int max_stack  = jvms()->stk_size();

   // Mismatch between method and jvms can occur since map briefly held

   // an OSR entry state (which takes up one RawPtr word).

   assert(max_locals == method()->max_locals(), "sanity");

   assert(max_stack  >= method()->max_stack(),  "sanity");

   assert((int)jvms()->endoff() == TypeFunc::Parms + max_locals + max_stack, "sanity");

   assert((int)jvms()->endoff() == (int)map()->req(), "sanity");

   // Find the start block.

   Block* osr_block = start_block();

   assert(osr_block->start() == osr_bci(), "sanity");

   // Set initial BCI.

   set_parse_bci(osr_block->start());

   // Set initial stack depth.

   set_sp(osr_block->start_sp());

   // Check bailouts.  We currently do not perform on stack replacement

   // of loops in catch blocks or loops which branch with a non-empty stack.

   if (sp() != 0) {

     C->record_method_not_compilable("OSR starts with non-empty stack");

     return;

   }

   // Do not OSR inside finally clauses:

   if (osr_block->has_trap_at(osr_block->start())) {

     C->record_method_not_compilable("OSR starts with an immediate trap");

     return;

   }

   // Commute monitors from interpreter frame to compiler frame.

   assert(jvms()->monitor_depth() == 0, "should be no active locks at beginning of osr");

   int mcnt = osr_block->flow()->monitor_count();

   Node *monitors_addr = basic_plus_adr(osr_buf, osr_buf, (max_locals+mcnt*2-1)*wordSize);

   for (index = 0; index < mcnt; index++) {

     // Make a BoxLockNode for the monitor.

     Node *box = _gvn.transform(new (C) BoxLockNode(next_monitor()));

     // Displaced headers and locked objects are interleaved in the

     // temp OSR buffer.  We only copy the locked objects out here.

     // Fetch the locked object from the OSR temp buffer and copy to our fastlock node.

     Node *lock_object = fetch_interpreter_state(index*2, T_OBJECT, monitors_addr, osr_buf);

     // Try and copy the displaced header to the BoxNode

     Node *displaced_hdr = fetch_interpreter_state((index*2) + 1, T_ADDRESS, monitors_addr, osr_buf);

     store_to_memory(control(), box, displaced_hdr, T_ADDRESS, Compile::AliasIdxRaw, MemNode::unordered);

     // Build a bogus FastLockNode (no code will be generated) and push the

     // monitor into our debug info.

     const FastLockNode *flock = _gvn.transform(new (C) FastLockNode( 0, lock_object, box ))->as_FastLock();

     map()->push_monitor(flock);

     // If the lock is our method synchronization lock, tuck it away in

     // _sync_lock for return and rethrow exit paths.

     if (index == 0 && method()->is_synchronized()) {

       _synch_lock = flock;

     }

   }

   // Use the raw liveness computation to make sure that unexpected

   // values don't propagate into the OSR frame.

   MethodLivenessResult live_locals = method()->liveness_at_bci(osr_bci());

   if (!live_locals.is_valid()) {

     // Degenerate or breakpointed method.

     C->record_method_not_compilable("OSR in empty or breakpointed method");

     return;

   }

   // Extract the needed locals from the interpreter frame.

   Node *locals_addr = basic_plus_adr(osr_buf, osr_buf, (max_locals-1)*wordSize);

   // find all the locals that the interpreter thinks contain live oops

   const BitMap live_oops = method()->live_local_oops_at_bci(osr_bci());

   for (index = 0; index < max_locals; index++) {

     if (!live_locals.at(index)) {

       continue;

     }

     const Type *type = osr_block->local_type_at(index);

     if (type->isa_oopptr() != NULL) {

       // 6403625: Verify that the interpreter oopMap thinks that the oop is live

       // else we might load a stale oop if the MethodLiveness disagrees with the

       // result of the interpreter. If the interpreter says it is dead we agree

       // by making the value go to top.

       //

       if (!live_oops.at(index)) {

         if (C->log() != NULL) {

           C->log()->elem("OSR_mismatch local_index='%d'",index);

         }

         set_local(index, null());

         // and ignore it for the loads

         continue;

       }

     }

     // Filter out TOP, HALF, and BOTTOM.  (Cf. ensure_phi.)

     if (type == Type::TOP || type == Type::HALF) {

       continue;

     }

     // If the type falls to bottom, then this must be a local that

     // is mixing ints and oops or some such.  Forcing it to top

     // makes it go dead.

     if (type == Type::BOTTOM) {

       continue;

     }

     // Construct code to access the appropriate local.

     BasicType bt = type->basic_type();

     if (type == TypePtr::NULL_PTR) {

       // Ptr types are mixed together with T_ADDRESS but NULL is

       // really for T_OBJECT types so correct it.

       bt = T_OBJECT;

     }

     Node *value = fetch_interpreter_state(index, bt, locals_addr, osr_buf);

     set_local(index, value);

   }

   // Extract the needed stack entries from the interpreter frame.

   for (index = 0; index < sp(); index++) {

     const Type *type = osr_block->stack_type_at(index);

     if (type != Type::TOP) {

       // Currently the compiler bails out when attempting to on stack replace

       // at a bci with a non-empty stack.  We should not reach here.

       ShouldNotReachHere();

     }

   }

   // End the OSR migration

   make_runtime_call(RC_LEAF, OptoRuntime::osr_end_Type(),

                     CAST_FROM_FN_PTR(address, SharedRuntime::OSR_migration_end),

                     "OSR_migration_end", TypeRawPtr::BOTTOM,

                     osr_buf);

   // Now that the interpreter state is loaded, make sure it will match

   // at execution time what the compiler is expecting now:

   SafePointNode* bad_type_exit = clone_map();

   bad_type_exit->set_control(new (C) RegionNode(1));

   assert(osr_block->flow()->jsrs()->size() == 0, "should be no jsrs live at osr point");

   for (index = 0; index < max_locals; index++) {

     if (stopped())  break;

     Node* l = local(index);

     if (l->is_top())  continue;  // nothing here

     const Type *type = osr_block->local_type_at(index);

     if (type->isa_oopptr() != NULL) {

       if (!live_oops.at(index)) {

         // skip type check for dead oops

         continue;

       }

     }

     if (osr_block->flow()->local_type_at(index)->is_return_address()) {

       // In our current system it's illegal for jsr addresses to be

       // live into an OSR entry point because the compiler performs

       // inlining of jsrs.  ciTypeFlow has a bailout that detect this

       // case and aborts the compile if addresses are live into an OSR

       // entry point.  Because of that we can assume that any address

       // locals at the OSR entry point are dead.  Method liveness

       // isn't precise enought to figure out that they are dead in all

       // cases so simply skip checking address locals all

       // together. Any type check is guaranteed to fail since the

       // interpreter type is the result of a load which might have any

       // value and the expected type is a constant.

       continue;

     }

     set_local(index, check_interpreter_type(l, type, bad_type_exit));

   }

   for (index = 0; index < sp(); index++) {

     if (stopped())  break;

     Node* l = stack(index);

     if (l->is_top())  continue;  // nothing here

     const Type *type = osr_block->stack_type_at(index);

     set_stack(index, check_interpreter_type(l, type, bad_type_exit));

   }

   if (bad_type_exit->control()->req() > 1) {

     // Build an uncommon trap here, if any inputs can be unexpected.

     bad_type_exit->set_control(_gvn.transform( bad_type_exit->control() ));

     record_for_igvn(bad_type_exit->control());

     SafePointNode* types_are_good = map();

     set_map(bad_type_exit);

     // The unexpected type happens because a new edge is active

     // in the CFG, which typeflow had previously ignored.

     // E.g., Object x = coldAtFirst() && notReached()? "str": new Integer(123).

     // This x will be typed as Integer if notReached is not yet linked.

     // It could also happen due to a problem in ciTypeFlow analysis.

     uncommon_trap(Deoptimization::Reason_constraint,

                   Deoptimization::Action_reinterpret);

     set_map(types_are_good);

   }

 }

 //------------------------------Parse------------------------------------------

 // Main parser constructor.

 Parse::Parse(JVMState* caller, ciMethod* parse_method, float expected_uses)

   : _exits(caller)

 {

   // Init some variables

   _caller = caller;

   _method = parse_method;

   _expected_uses = expected_uses;

   _depth = 1 + (caller->has_method() ? caller->depth() : 0);

   _wrote_final = false;

   _wrote_volatile = false;

   _alloc_with_final = NULL;

   _entry_bci = InvocationEntryBci;

   _tf = NULL;

   _block = NULL;

   _first_return = true;

   _replaced_nodes_for_exceptions = false;

   _new_idx = C->unique();

   debug_only(_block_count = -1);

   debug_only(_blocks = (Block*)-1);

 #ifndef PRODUCT

   if (PrintCompilation || PrintOpto) {

     // Make sure I have an inline tree, so I can print messages about it.

     JVMState* ilt_caller = is_osr_parse() ? caller->caller() : caller;

     InlineTree::find_subtree_from_root(C->ilt(), ilt_caller, parse_method);

   }

   _max_switch_depth = 0;

   _est_switch_depth = 0;

 #endif

   _tf = TypeFunc::make(method());

   _iter.reset_to_method(method());

   _flow = method()->get_flow_analysis();

   if (_flow->failing()) {

     C->record_method_not_compilable_all_tiers(_flow->failure_reason());

   }

 #ifndef PRODUCT

   if (_flow->has_irreducible_entry()) {

     C->set_parsed_irreducible_loop(true);

   }

 #endif

   if (_expected_uses <= 0) {

     _prof_factor = 1;

   } else {

     float prof_total = parse_method->interpreter_invocation_count();

     if (prof_total <= _expected_uses) {

       _prof_factor = 1;

     } else {

       _prof_factor = _expected_uses / prof_total;

     }

   }

   CompileLog* log = C->log();

   if (log != NULL) {

     log->begin_head("parse method='%d' uses='%g'",

                     log->identify(parse_method), expected_uses);

     if (depth() == 1 && C->is_osr_compilation()) {

       log->print(" osr_bci='%d'", C->entry_bci());

     }

     log->stamp();

     log->end_head();

   }

   // Accumulate deoptimization counts.

   // (The range_check and store_check counts are checked elsewhere.)

   ciMethodData* md = method()->method_data();

   for (uint reason = 0; reason < md->trap_reason_limit(); reason++) {

     uint md_count = md->trap_count(reason);

     if (md_count != 0) {

       if (md_count == md->trap_count_limit())

         md_count += md->overflow_trap_count();

       uint total_count = C->trap_count(reason);

       uint old_count   = total_count;

       total_count += md_count;

       // Saturate the add if it overflows.

       if (total_count < old_count || total_count < md_count)

         total_count = (uint)-1;

       C->set_trap_count(reason, total_count);

       if (log != NULL)

         log->elem("observe trap='%s' count='%d' total='%d'",

                   Deoptimization::trap_reason_name(reason),

                   md_count, total_count);

     }

   }

   // Accumulate total sum of decompilations, also.

   C->set_decompile_count(C->decompile_count() + md->decompile_count());

   _count_invocations = C->do_count_invocations();

   _method_data_update = C->do_method_data_update();

   if (log != NULL && method()->has_exception_handlers()) {

     log->elem("observe that='has_exception_handlers'");

   }

   assert(method()->can_be_compiled(),       "Can not parse this method, cutout earlier");

   assert(method()->has_balanced_monitors(), "Can not parse unbalanced monitors, cutout earlier");

   // Always register dependence if JVMTI is enabled, because

   // either breakpoint setting or hotswapping of methods may

   // cause deoptimization.

   if (C->env()->jvmti_can_hotswap_or_post_breakpoint()) {

     C->dependencies()->assert_evol_method(method());

   }

   methods_seen++;

   // Do some special top-level things.

   if (depth() == 1 && C->is_osr_compilation()) {

     _entry_bci = C->entry_bci();

     _flow = method()->get_osr_flow_analysis(osr_bci());

     if (_flow->failing()) {

       C->record_method_not_compilable(_flow->failure_reason());

 #ifndef PRODUCT

       if (PrintOpto && (Verbose || WizardMode)) {

         tty->print_cr("OSR @%d type flow bailout: %s", _entry_bci, _flow->failure_reason());

         if (Verbose) {

           method()->print();

           method()->print_codes();

           _flow->print();

         }

       }

 #endif

     }

     _tf = C->tf();     // the OSR entry type is different

   }

 #ifdef ASSERT

   if (depth() == 1) {

     assert(C->is_osr_compilation() == this->is_osr_parse(), "OSR in sync");

     if (C->tf() != tf()) {

       MutexLockerEx ml(Compile_lock, Mutex::_no_safepoint_check_flag);

       assert(C->env()->system_dictionary_modification_counter_changed(),

              "Must invalidate if TypeFuncs differ");

     }

   } else {

     assert(!this->is_osr_parse(), "no recursive OSR");

   }

 #endif

   methods_parsed++;

 #ifndef PRODUCT

   // add method size here to guarantee that inlined methods are added too

   if (TimeCompiler)

     _total_bytes_compiled += method()->code_size();

   show_parse_info();

 #endif

   if (failing()) {

     if (log)  log->done("parse");

     return;

   }

   gvn().set_type(root(), root()->bottom_type());

   gvn().transform(top());

   // Import the results of the ciTypeFlow.

   init_blocks();

   // Merge point for all normal exits

   build_exits();

   // Setup the initial JVM state map.

   SafePointNode* entry_map = create_entry_map();

   // Check for bailouts during map initialization

   if (failing() || entry_map == NULL) {

     if (log)  log->done("parse");

     return;

   }

   Node_Notes* caller_nn = C->default_node_notes();

   // Collect debug info for inlined calls unless -XX:-DebugInlinedCalls.

   if (DebugInlinedCalls || depth() == 1) {

     C->set_default_node_notes(make_node_notes(caller_nn));

   }

   if (is_osr_parse()) {

     Node* osr_buf = entry_map->in(TypeFunc::Parms+0);

     entry_map->set_req(TypeFunc::Parms+0, top());

     set_map(entry_map);

     load_interpreter_state(osr_buf);

   } else {

     set_map(entry_map);

     do_method_entry();

   }

   if (depth() == 1 && !failing()) {

     // Add check to deoptimize the nmethod if RTM state was changed

     rtm_deopt();

   }

   // Check for bailouts during method entry or RTM state check setup.

   if (failing()) {

     if (log)  log->done("parse");

     C->set_default_node_notes(caller_nn);

     return;

   }

   entry_map = map();  // capture any changes performed by method setup code

   assert(jvms()->endoff() == map()->req(), "map matches JVMS layout");

   // We begin parsing as if we have just encountered a jump to the

   // method entry.

   Block* entry_block = start_block();

   assert(entry_block->start() == (is_osr_parse() ? osr_bci() : 0), "");

   set_map_clone(entry_map);

   merge_common(entry_block, entry_block->next_path_num());

 #ifndef PRODUCT

   BytecodeParseHistogram *parse_histogram_obj = new (C->env()->arena()) BytecodeParseHistogram(this, C);

   set_parse_histogram( parse_histogram_obj );

 #endif

   // Parse all the basic blocks.

   do_all_blocks();

   C->set_default_node_notes(caller_nn);

   // Check for bailouts during conversion to graph

   if (failing()) {

     if (log)  log->done("parse");

     return;

   }

   // Fix up all exiting control flow.

   set_map(entry_map);

   do_exits();

   if (log)  log->done("parse nodes='%d' live='%d' memory='" SIZE_FORMAT "'",

                       C->unique(), C->live_nodes(), C->node_arena()->used());

 }

 //---------------------------do_all_blocks-------------------------------------

 void Parse::do_all_blocks() {

   bool has_irreducible = flow()->has_irreducible_entry();

   // Walk over all blocks in Reverse Post-Order.

   while (true) {

     bool progress = false;

     for (int rpo = 0; rpo < block_count(); rpo++) {

       Block* block = rpo_at(rpo);

       if (block->is_parsed()) continue;

       if (!block->is_merged()) {

         // Dead block, no state reaches this block

         continue;

       }

       // Prepare to parse this block.

       load_state_from(block);

       if (stopped()) {

         // Block is dead.

         continue;

       }

       blocks_parsed++;

       progress = true;

       if (block->is_loop_head() || block->is_handler() || has_irreducible && !block->is_ready()) {

         // Not all preds have been parsed.  We must build phis everywhere.

         // (Note that dead locals do not get phis built, ever.)

         ensure_phis_everywhere();

         if (block->is_SEL_head() &&

             (UseLoopPredicate || LoopLimitCheck)) {

           // Add predicate to single entry (not irreducible) loop head.

           assert(!block->has_merged_backedge(), "only entry paths should be merged for now");

           // Need correct bci for predicate.

           // It is fine to set it here since do_one_block() will set it anyway.

           set_parse_bci(block->start());

           add_predicate();

           // Add new region for back branches.

           int edges = block->pred_count() - block->preds_parsed() + 1; // +1 for original region

           RegionNode *r = new (C) RegionNode(edges+1);

           _gvn.set_type(r, Type::CONTROL);

           record_for_igvn(r);

           r->init_req(edges, control());

           set_control(r);

           // Add new phis.

           ensure_phis_everywhere();

         }

         // Leave behind an undisturbed copy of the map, for future merges.

         set_map(clone_map());

       }

       if (control()->is_Region() && !block->is_loop_head() && !has_irreducible && !block->is_handler()) {

         // In the absence of irreducible loops, the Region and Phis

         // associated with a merge that doesn't involve a backedge can

         // be simplified now since the RPO parsing order guarantees

         // that any path which was supposed to reach here has already

         // been parsed or must be dead.

         Node* c = control();

         Node* result = _gvn.transform_no_reclaim(control());

         if (c != result && TraceOptoParse) {

           tty->print_cr("Block #%d replace %d with %d", block->rpo(), c->_idx, result->_idx);

         }

         if (result != top()) {

           record_for_igvn(result);

         }

       }

       // Parse the block.

       do_one_block();

       // Check for bailouts.

       if (failing())  return;

     }

     // with irreducible loops multiple passes might be necessary to parse everything

     if (!has_irreducible || !progress) {

       break;

     }

   }

   blocks_seen += block_count();

 #ifndef PRODUCT

   // Make sure there are no half-processed blocks remaining.

   // Every remaining unprocessed block is dead and may be ignored now.

   for (int rpo = 0; rpo < block_count(); rpo++) {

     Block* block = rpo_at(rpo);

     if (!block->is_parsed()) {

       if (TraceOptoParse) {

         tty->print_cr("Skipped dead block %d at bci:%d", rpo, block->start());

       }

       assert(!block->is_merged(), "no half-processed blocks");

     }

   }

 #endif

 }

 static Node* mask_int_value(Node* v, BasicType bt, PhaseGVN* gvn) {

   Compile* C = gvn->C;

   switch (bt) {

   case T_BYTE:

     v = gvn->transform(new (C) LShiftINode(v, gvn->intcon(24)));

     v = gvn->transform(new (C) RShiftINode(v, gvn->intcon(24)));

     break;

   case T_SHORT:

     v = gvn->transform(new (C) LShiftINode(v, gvn->intcon(16)));

     v = gvn->transform(new (C) RShiftINode(v, gvn->intcon(16)));

     break;

   case T_CHAR:

     v = gvn->transform(new (C) AndINode(v, gvn->intcon(0xFFFF)));

     break;

   case T_BOOLEAN:

     v = gvn->transform(new (C) AndINode(v, gvn->intcon(0x1)));

     break;

   }

   return v;

 }

 //-------------------------------build_exits----------------------------------

 // Build normal and exceptional exit merge points.

 void Parse::build_exits() {

   // make a clone of caller to prevent sharing of side-effects

   _exits.set_map(_exits.clone_map());

   _exits.clean_stack(_exits.sp());

   _exits.sync_jvms();

   RegionNode* region = new (C) RegionNode(1);

   record_for_igvn(region);

   gvn().set_type_bottom(region);

   _exits.set_control(region);

   // Note:  iophi and memphi are not transformed until do_exits.

   Node* iophi  = new (C) PhiNode(region, Type::ABIO);

   Node* memphi = new (C) PhiNode(region, Type::MEMORY, TypePtr::BOTTOM);

   gvn().set_type_bottom(iophi);

   gvn().set_type_bottom(memphi);

   _exits.set_i_o(iophi);

   _exits.set_all_memory(memphi);

   // Add a return value to the exit state.  (Do not push it yet.)

   if (tf()->range()->cnt() > TypeFunc::Parms) {

     const Type* ret_type = tf()->range()->field_at(TypeFunc::Parms);

     if (ret_type->isa_int()) {

       BasicType ret_bt = method()->return_type()->basic_type();

       if (ret_bt == T_BOOLEAN ||

           ret_bt == T_CHAR ||

           ret_bt == T_BYTE ||

           ret_bt == T_SHORT) {

         ret_type = TypeInt::INT;

       }

     }

     // Don't "bind" an unloaded return klass to the ret_phi. If the klass

     // becomes loaded during the subsequent parsing, the loaded and unloaded

     // types will not join when we transform and push in do_exits().

     const TypeOopPtr* ret_oop_type = ret_type->isa_oopptr();

     if (ret_oop_type && !ret_oop_type->klass()->is_loaded()) {

       ret_type = TypeOopPtr::BOTTOM;

     }

     int         ret_size = type2size[ret_type->basic_type()];

     Node*       ret_phi  = new (C) PhiNode(region, ret_type);

     gvn().set_type_bottom(ret_phi);

     _exits.ensure_stack(ret_size);

     assert((int)(tf()->range()->cnt() - TypeFunc::Parms) == ret_size, "good tf range");

     assert(method()->return_type()->size() == ret_size, "tf agrees w/ method");

     _exits.set_argument(0, ret_phi);  // here is where the parser finds it

     // Note:  ret_phi is not yet pushed, until do_exits.

   }

 }

 //----------------------------build_start_state-------------------------------

 // Construct a state which contains only the incoming arguments from an

 // unknown caller.  The method & bci will be NULL & InvocationEntryBci.

 JVMState* Compile::build_start_state(StartNode* start, const TypeFunc* tf) {

   int        arg_size = tf->domain()->cnt();

   int        max_size = MAX2(arg_size, (int)tf->range()->cnt());

   JVMState*  jvms     = new (this) JVMState(max_size - TypeFunc::Parms);

   SafePointNode* map  = new (this) SafePointNode(max_size, NULL);

   record_for_igvn(map);

   assert(arg_size == TypeFunc::Parms + (is_osr_compilation() ? 1 : method()->arg_size()), "correct arg_size");

   Node_Notes* old_nn = default_node_notes();

   if (old_nn != NULL && has_method()) {

     Node_Notes* entry_nn = old_nn->clone(this);

     JVMState* entry_jvms = new(this) JVMState(method(), old_nn->jvms());

     entry_jvms->set_offsets(0);

     entry_jvms->set_bci(entry_bci());

     entry_nn->set_jvms(entry_jvms);

     set_default_node_notes(entry_nn);

   }

   uint i;

   for (i = 0; i < (uint)arg_size; i++) {

     Node* parm = initial_gvn()->transform(new (this) ParmNode(start, i));

     map->init_req(i, parm);

     // Record all these guys for later GVN.

     record_for_igvn(parm);

   }

   for (; i < map->req(); i++) {

     map->init_req(i, top());

   }

   assert(jvms->argoff() == TypeFunc::Parms, "parser gets arguments here");

   set_default_node_notes(old_nn);

   map->set_jvms(jvms);

   jvms->set_map(map);

   return jvms;

 }

 //-----------------------------make_node_notes---------------------------------

 Node_Notes* Parse::make_node_notes(Node_Notes* caller_nn) {

   if (caller_nn == NULL)  return NULL;

   Node_Notes* nn = caller_nn->clone(C);

   JVMState* caller_jvms = nn->jvms();

   JVMState* jvms = new (C) JVMState(method(), caller_jvms);

   jvms->set_offsets(0);

   jvms->set_bci(_entry_bci);

   nn->set_jvms(jvms);

   return nn;

 }

 //--------------------------return_values--------------------------------------

 void Compile::return_values(JVMState* jvms) {

   GraphKit kit(jvms);

   Node* ret = new (this) ReturnNode(TypeFunc::Parms,

                              kit.control(),

                              kit.i_o(),

                              kit.reset_memory(),

                              kit.frameptr(),

                              kit.returnadr());

   // Add zero or 1 return values

   int ret_size = tf()->range()->cnt() - TypeFunc::Parms;

   if (ret_size > 0) {

     kit.inc_sp(-ret_size);  // pop the return value(s)

     kit.sync_jvms();

     ret->add_req(kit.argument(0));

     // Note:  The second dummy edge is not needed by a ReturnNode.

   }

   // bind it to root

   root()->add_req(ret);

   record_for_igvn(ret);

   initial_gvn()->transform_no_reclaim(ret);

 }

 //------------------------rethrow_exceptions-----------------------------------

 // Bind all exception states in the list into a single RethrowNode.

 void Compile::rethrow_exceptions(JVMState* jvms) {

   GraphKit kit(jvms);

   if (!kit.has_exceptions())  return;  // nothing to generate

   // Load my combined exception state into the kit, with all phis transformed:

   SafePointNode* ex_map = kit.combine_and_pop_all_exception_states();

   Node* ex_oop = kit.use_exception_state(ex_map);

   RethrowNode* exit = new (this) RethrowNode(kit.control(),

                                       kit.i_o(), kit.reset_memory(),

                                       kit.frameptr(), kit.returnadr(),

                                       // like a return but with exception input

                                       ex_oop);

   // bind to root

   root()->add_req(exit);

   record_for_igvn(exit);

   initial_gvn()->transform_no_reclaim(exit);

 }

 //---------------------------do_exceptions-------------------------------------

 // Process exceptions arising from the current bytecode.

 // Send caught exceptions to the proper handler within this method.

 // Unhandled exceptions feed into _exit.

 void Parse::do_exceptions() {

   if (!has_exceptions())  return;

   if (failing()) {

     // Pop them all off and throw them away.

     while (pop_exception_state() != NULL) ;

     return;

   }

   PreserveJVMState pjvms(this, false);

   SafePointNode* ex_map;

   while ((ex_map = pop_exception_state()) != NULL) {

     if (!method()->has_exception_handlers()) {

       // Common case:  Transfer control outward.

       // Doing it this early allows the exceptions to common up

       // even between adjacent method calls.

       throw_to_exit(ex_map);

     } else {

       // Have to look at the exception first.

       assert(stopped(), "catch_inline_exceptions trashes the map");

       catch_inline_exceptions(ex_map);

       stop_and_kill_map();      // we used up this exception state; kill it

     }

   }

   // We now return to our regularly scheduled program:

 }

 //---------------------------throw_to_exit-------------------------------------

 // Merge the given map into an exception exit from this method.

 // The exception exit will handle any unlocking of receiver.

 // The ex_oop must be saved within the ex_map, unlike merge_exception.

 void Parse::throw_to_exit(SafePointNode* ex_map) {

   // Pop the JVMS to (a copy of) the caller.

   GraphKit caller;

   caller.set_map_clone(_caller->map());

   caller.set_bci(_caller->bci());

   caller.set_sp(_caller->sp());

   // Copy out the standard machine state:

   for (uint i = 0; i < TypeFunc::Parms; i++) {

     caller.map()->set_req(i, ex_map->in(i));

   }

   if (ex_map->has_replaced_nodes()) {

     _replaced_nodes_for_exceptions = true;

   }

   caller.map()->transfer_replaced_nodes_from(ex_map, _new_idx);

   // ...and the exception:

   Node*          ex_oop        = saved_ex_oop(ex_map);

   SafePointNode* caller_ex_map = caller.make_exception_state(ex_oop);

   // Finally, collect the new exception state in my exits:

   _exits.add_exception_state(caller_ex_map);

 }

 //------------------------------do_exits---------------------------------------

 void Parse::do_exits() {

   set_parse_bci(InvocationEntryBci);

   // Now peephole on the return bits

   Node* region = _exits.control();

   _exits.set_control(gvn().transform(region));

   Node* iophi = _exits.i_o();

   _exits.set_i_o(gvn().transform(iophi));

   // On PPC64, also add MemBarRelease for constructors which write

   // volatile fields. As support_IRIW_for_not_multiple_copy_atomic_cpu

   // is set on PPC64, no sync instruction is issued after volatile

   // stores. We want to quarantee the same behaviour as on platforms

   // with total store order, although this is not required by the Java

   // memory model. So as with finals, we add a barrier here.

   if (wrote_final() PPC64_ONLY(|| (wrote_volatile() && method()->is_initializer()))) {

     // This method (which must be a constructor by the rules of Java)

     // wrote a final.  The effects of all initializations must be

     // committed to memory before any code after the constructor

     // publishes the reference to the newly constructor object.

     // Rather than wait for the publication, we simply block the

     // writes here.  Rather than put a barrier on only those writes

     // which are required to complete, we force all writes to complete.

     //

     // "All bets are off" unless the first publication occurs after a

     // normal return from the constructor.  We do not attempt to detect

     // such unusual early publications.  But no barrier is needed on

     // exceptional returns, since they cannot publish normally.

     //

     _exits.insert_mem_bar(Op_MemBarRelease, alloc_with_final());

 #ifndef PRODUCT

     if (PrintOpto && (Verbose || WizardMode)) {

       method()->print_name();

       tty->print_cr(" writes finals and needs a memory barrier");

     }

 #endif

   }

   for (MergeMemStream mms(_exits.merged_memory()); mms.next_non_empty(); ) {

     // transform each slice of the original memphi:

     mms.set_memory(_gvn.transform(mms.memory()));

   }

   if (tf()->range()->cnt() > TypeFunc::Parms) {

     const Type* ret_type = tf()->range()->field_at(TypeFunc::Parms);

     Node*       ret_phi  = _gvn.transform( _exits.argument(0) );

     if (!_exits.control()->is_top() && _gvn.type(ret_phi)->empty()) {

       // In case of concurrent class loading, the type we set for the

       // ret_phi in build_exits() may have been too optimistic and the

       // ret_phi may be top now.

       // Otherwise, we've encountered an error and have to mark the method as

       // not compilable. Just using an assertion instead would be dangerous

       // as this could lead to an infinite compile loop in non-debug builds.

       {

         MutexLockerEx ml(Compile_lock, Mutex::_no_safepoint_check_flag);

         if (C->env()->system_dictionary_modification_counter_changed()) {

           C->record_failure(C2Compiler::retry_class_loading_during_parsing());

         } else {

           C->record_method_not_compilable("Can't determine return type.");

         }

       }

       return;

     }

     if (ret_type->isa_int()) {

       BasicType ret_bt = method()->return_type()->basic_type();

       ret_phi = mask_int_value(ret_phi, ret_bt, &_gvn);

     }

     _exits.push_node(ret_type->basic_type(), ret_phi);

   }

   // Note:  Logic for creating and optimizing the ReturnNode is in Compile.

   // Unlock along the exceptional paths.

   // This is done late so that we can common up equivalent exceptions

   // (e.g., null checks) arising from multiple points within this method.

   // See GraphKit::add_exception_state, which performs the commoning.

   bool do_synch = method()->is_synchronized() && GenerateSynchronizationCode;

   // record exit from a method if compiled while Dtrace is turned on.

   if (do_synch || C->env()->dtrace_method_probes() || _replaced_nodes_for_exceptions) {

     // First move the exception list out of _exits:

     GraphKit kit(_exits.transfer_exceptions_into_jvms());

     SafePointNode* normal_map = kit.map();  // keep this guy safe

     // Now re-collect the exceptions into _exits:

     SafePointNode* ex_map;

     while ((ex_map = kit.pop_exception_state()) != NULL) {

       Node* ex_oop = kit.use_exception_state(ex_map);

       // Force the exiting JVM state to have this method at InvocationEntryBci.

       // The exiting JVM state is otherwise a copy of the calling JVMS.

       JVMState* caller = kit.jvms();

       JVMState* ex_jvms = caller->clone_shallow(C);

       ex_jvms->set_map(kit.clone_map());

       ex_jvms->map()->set_jvms(ex_jvms);

       ex_jvms->set_bci(   InvocationEntryBci);

       kit.set_jvms(ex_jvms);

       if (do_synch) {

         // Add on the synchronized-method box/object combo

         kit.map()->push_monitor(_synch_lock);

         // Unlock!

         kit.shared_unlock(_synch_lock->box_node(), _synch_lock->obj_node());

       }

       if (C->env()->dtrace_method_probes()) {

         kit.make_dtrace_method_exit(method());

       }

       if (_replaced_nodes_for_exceptions) {

         kit.map()->apply_replaced_nodes(_new_idx);

       }

       // Done with exception-path processing.

       ex_map = kit.make_exception_state(ex_oop);

       assert(ex_jvms->same_calls_as(ex_map->jvms()), "sanity");

       // Pop the last vestige of this method:

       ex_map->set_jvms(caller->clone_shallow(C));

       ex_map->jvms()->set_map(ex_map);

       _exits.push_exception_state(ex_map);

     }

     assert(_exits.map() == normal_map, "keep the same return state");

   }

   {

     // Capture very early exceptions (receiver null checks) from caller JVMS

     GraphKit caller(_caller);

     SafePointNode* ex_map;

     while ((ex_map = caller.pop_exception_state()) != NULL) {

       _exits.add_exception_state(ex_map);

     }

   }

   _exits.map()->apply_replaced_nodes(_new_idx);

 }

 //-----------------------------create_entry_map-------------------------------

 // Initialize our parser map to contain the types at method entry.

 // For OSR, the map contains a single RawPtr parameter.

 // Initial monitor locking for sync. methods is performed by do_method_entry.

 SafePointNode* Parse::create_entry_map() {

   // Check for really stupid bail-out cases.

   uint len = TypeFunc::Parms + method()->max_locals() + method()->max_stack();

   if (len >= 32760) {

     C->record_method_not_compilable_all_tiers("too many local variables");

     return NULL;

   }

   // clear current replaced nodes that are of no use from here on (map was cloned in build_exits).

   _caller->map()->delete_replaced_nodes();

   // If this is an inlined method, we may have to do a receiver null check.

   if (_caller->has_method() && is_normal_parse() && !method()->is_static()) {

     GraphKit kit(_caller);

     kit.null_check_receiver_before_call(method());

     _caller = kit.transfer_exceptions_into_jvms();

     if (kit.stopped()) {

       _exits.add_exception_states_from(_caller);

       _exits.set_jvms(_caller);

       return NULL;

     }

   }

   assert(method() != NULL, "parser must have a method");

   // Create an initial safepoint to hold JVM state during parsing

   JVMState* jvms = new (C) JVMState(method(), _caller->has_method() ? _caller : NULL);

   set_map(new (C) SafePointNode(len, jvms));

   jvms->set_map(map());

   record_for_igvn(map());

   assert(jvms->endoff() == len, "correct jvms sizing");

   SafePointNode* inmap = _caller->map();

   assert(inmap != NULL, "must have inmap");

   // In case of null check on receiver above

   map()->transfer_replaced_nodes_from(inmap, _new_idx);

   uint i;

   // Pass thru the predefined input parameters.

   for (i = 0; i < TypeFunc::Parms; i++) {

     map()->init_req(i, inmap->in(i));

   }

   if (depth() == 1) {

     assert(map()->memory()->Opcode() == Op_Parm, "");

     // Insert the memory aliasing node

     set_all_memory(reset_memory());

   }

   assert(merged_memory(), "");

   // Now add the locals which are initially bound to arguments:

   uint arg_size = tf()->domain()->cnt();

   ensure_stack(arg_size - TypeFunc::Parms);  // OSR methods have funny args

   for (i = TypeFunc::Parms; i < arg_size; i++) {

     map()->init_req(i, inmap->argument(_caller, i - TypeFunc::Parms));

   }

   // Clear out the rest of the map (locals and stack)

   for (i = arg_size; i < len; i++) {

     map()->init_req(i, top());

   }

   SafePointNode* entry_map = stop();

   return entry_map;

 }

 //-----------------------------do_method_entry--------------------------------

 // Emit any code needed in the pseudo-block before BCI zero.

 // The main thing to do is lock the receiver of a synchronized method.

 void Parse::do_method_entry() {

   set_parse_bci(InvocationEntryBci); // Pseudo-BCP

   set_sp(0);                      // Java Stack Pointer

   NOT_PRODUCT( count_compiled_calls(true/*at_method_entry*/, false/*is_inline*/); )

   if (C->env()->dtrace_method_probes()) {

     make_dtrace_method_entry(method());

   }

   // If the method is synchronized, we need to construct a lock node, attach

   // it to the Start node, and pin it there.

   if (method()->is_synchronized()) {

     // Insert a FastLockNode right after the Start which takes as arguments

     // the current thread pointer, the "this" pointer & the address of the

     // stack slot pair used for the lock.  The "this" pointer is a projection

     // off the start node, but the locking spot has to be constructed by

     // creating a ConLNode of 0, and boxing it with a BoxLockNode.  The BoxLockNode

     // becomes the second argument to the FastLockNode call.  The

     // FastLockNode becomes the new control parent to pin it to the start.

     // Setup Object Pointer

     Node *lock_obj = NULL;

     if(method()->is_static()) {

       ciInstance* mirror = _method->holder()->java_mirror();

       const TypeInstPtr *t_lock = TypeInstPtr::make(mirror);

       lock_obj = makecon(t_lock);

     } else {                  // Else pass the "this" pointer,

       lock_obj = local(0);    // which is Parm0 from StartNode

     }

     // Clear out dead values from the debug info.

     kill_dead_locals();

     // Build the FastLockNode

     _synch_lock = shared_lock(lock_obj);

   }

   // Feed profiling data for parameters to the type system so it can

   // propagate it as speculative types

   record_profiled_parameters_for_speculation();

   if (depth() == 1) {

     increment_and_test_invocation_counter(Tier2CompileThreshold);

   }

 }

 //------------------------------init_blocks------------------------------------

 // Initialize our parser map to contain the types/monitors at method entry.

 void Parse::init_blocks() {

   // Create the blocks.

   _block_count = flow()->block_count();

   _blocks = NEW_RESOURCE_ARRAY(Block, _block_count);

   Copy::zero_to_bytes(_blocks, sizeof(Block)*_block_count);

   int rpo;

   // Initialize the structs.

   for (rpo = 0; rpo < block_count(); rpo++) {

     Block* block = rpo_at(rpo);

     block->init_node(this, rpo);

   }

   // Collect predecessor and successor information.

   for (rpo = 0; rpo < block_count(); rpo++) {

     Block* block = rpo_at(rpo);

     block->init_graph(this);

   }

 }

 //-------------------------------init_node-------------------------------------

 void Parse::Block::init_node(Parse* outer, int rpo) {

   _flow = outer->flow()->rpo_at(rpo);

   _pred_count = 0;

   _preds_parsed = 0;

   _count = 0;

   assert(pred_count() == 0 && preds_parsed() == 0, "sanity");

   assert(!(is_merged() || is_parsed() || is_handler() || has_merged_backedge()), "sanity");

   assert(_live_locals.size() == 0, "sanity");

   // entry point has additional predecessor

   if (flow()->is_start())  _pred_count++;

   assert(flow()->is_start() == (this == outer->start_block()), "");

 }

 //-------------------------------init_graph------------------------------------

 void Parse::Block::init_graph(Parse* outer) {

   // Create the successor list for this parser block.

   GrowableArray<ciTypeFlow::Block*>* tfs = flow()->successors();

   GrowableArray<ciTypeFlow::Block*>* tfe = flow()->exceptions();

   int ns = tfs->length();

   int ne = tfe->length();

   _num_successors = ns;

   _all_successors = ns+ne;

   _successors = (ns+ne == 0) ? NULL : NEW_RESOURCE_ARRAY(Block*, ns+ne);

   int p = 0;

   for (int i = 0; i < ns+ne; i++) {

     ciTypeFlow::Block* tf2 = (i < ns) ? tfs->at(i) : tfe->at(i-ns);

     Block* block2 = outer->rpo_at(tf2->rpo());

     _successors[i] = block2;

     // Accumulate pred info for the other block, too.

     if (i < ns) {

       block2->_pred_count++;

     } else {

       block2->_is_handler = true;

     }

     #ifdef ASSERT

     // A block's successors must be distinguishable by BCI.

     // That is, no bytecode is allowed to branch to two different

     // clones of the same code location.

     for (int j = 0; j < i; j++) {

       Block* block1 = _successors[j];

       if (block1 == block2)  continue;  // duplicates are OK

       assert(block1->start() != block2->start(), "successors have unique bcis");

     }

     #endif

   }

   // Note: We never call next_path_num along exception paths, so they

   // never get processed as "ready".  Also, the input phis of exception

   // handlers get specially processed, so that

 }

 //---------------------------successor_for_bci---------------------------------

 Parse::Block* Parse::Block::successor_for_bci(int bci) {

   for (int i = 0; i < all_successors(); i++) {

     Block* block2 = successor_at(i);

     if (block2->start() == bci)  return block2;

   }

   // We can actually reach here if ciTypeFlow traps out a block

   // due to an unloaded class, and concurrently with compilation the

   // class is then loaded, so that a later phase of the parser is

   // able to see more of the bytecode CFG.  Or, the flow pass and

   // the parser can have a minor difference of opinion about executability

   // of bytecodes.  For example, "obj.field = null" is executable even

   // if the field's type is an unloaded class; the flow pass used to

   // make a trap for such code.

   return NULL;

 }

 //-----------------------------stack_type_at-----------------------------------

 const Type* Parse::Block::stack_type_at(int i) const {

   return get_type(flow()->stack_type_at(i));

 }

 //-----------------------------local_type_at-----------------------------------

 const Type* Parse::Block::local_type_at(int i) const {

   // Make dead locals fall to bottom.

   if (_live_locals.size() == 0) {

     MethodLivenessResult live_locals = flow()->outer()->method()->liveness_at_bci(start());

     // This bitmap can be zero length if we saw a breakpoint.

     // In such cases, pretend they are all live.

     ((Block*)this)->_live_locals = live_locals;

   }

   if (_live_locals.size() > 0 && !_live_locals.at(i))

     return Type::BOTTOM;

   return get_type(flow()->local_type_at(i));

 }

 #ifndef PRODUCT

 //----------------------------name_for_bc--------------------------------------

 // helper method for BytecodeParseHistogram

 static const char* name_for_bc(int i) {

   return Bytecodes::is_defined(i) ? Bytecodes::name(Bytecodes::cast(i)) : "xxxunusedxxx";

 }

 //----------------------------BytecodeParseHistogram------------------------------------

 Parse::BytecodeParseHistogram::BytecodeParseHistogram(Parse *p, Compile *c) {

   _parser   = p;

   _compiler = c;

   if( ! _initialized ) { _initialized = true; reset(); }

 }

 //----------------------------current_count------------------------------------

 int Parse::BytecodeParseHistogram::current_count(BPHType bph_type) {

   switch( bph_type ) {

   case BPH_transforms: { return _parser->gvn().made_progress(); }

   case BPH_values:     { return _parser->gvn().made_new_values(); }

   default: { ShouldNotReachHere(); return 0; }

   }

 }

 //----------------------------initialized--------------------------------------

 bool Parse::BytecodeParseHistogram::initialized() { return _initialized; }

 //----------------------------reset--------------------------------------------

 void Parse::BytecodeParseHistogram::reset() {

   int i = Bytecodes::number_of_codes;

   while (i-- > 0) { _bytecodes_parsed[i] = 0; _nodes_constructed[i] = 0; _nodes_transformed[i] = 0; _new_values[i] = 0; }

 }

 //----------------------------set_initial_state--------------------------------

 // Record info when starting to parse one bytecode

 void Parse::BytecodeParseHistogram::set_initial_state( Bytecodes::Code bc ) {

   if( PrintParseStatistics && !_parser->is_osr_parse() ) {

     _initial_bytecode    = bc;

     _initial_node_count  = _compiler->unique();

     _initial_transforms  = current_count(BPH_transforms);

     _initial_values      = current_count(BPH_values);

   }

 }

 //----------------------------record_change--------------------------------

 // Record results of parsing one bytecode

 void Parse::BytecodeParseHistogram::record_change() {

   if( PrintParseStatistics && !_parser->is_osr_parse() ) {

     ++_bytecodes_parsed[_initial_bytecode];

     _nodes_constructed [_initial_bytecode] += (_compiler->unique() - _initial_node_count);

     _nodes_transformed [_initial_bytecode] += (current_count(BPH_transforms) - _initial_transforms);

     _new_values        [_initial_bytecode] += (current_count(BPH_values)     - _initial_values);

   }

 }

 //----------------------------print--------------------------------------------

 void Parse::BytecodeParseHistogram::print(float cutoff) {

   ResourceMark rm;

   // print profile

   int total  = 0;

   int i      = 0;

   for( i = 0; i < Bytecodes::number_of_codes; ++i ) { total += _bytecodes_parsed[i]; }

   int abs_sum = 0;

   tty->cr();   //0123456789012345678901234567890123456789012345678901234567890123456789

   tty->print_cr("Histogram of %d parsed bytecodes:", total);

   if( total == 0 ) { return; }

   tty->cr();

   tty->print_cr("absolute:  count of compiled bytecodes of this type");

   tty->print_cr("relative:  percentage contribution to compiled nodes");

   tty->print_cr("nodes   :  Average number of nodes constructed per bytecode");

   tty->print_cr("rnodes  :  Significance towards total nodes constructed, (nodes*relative)");

   tty->print_cr("transforms: Average amount of tranform progress per bytecode compiled");

   tty->print_cr("values  :  Average number of node values improved per bytecode");

   tty->print_cr("name    :  Bytecode name");

   tty->cr();

   tty->print_cr("  absolute  relative   nodes  rnodes  transforms  values   name");

   tty->print_cr("----------------------------------------------------------------------");

   while (--i > 0) {

     int       abs = _bytecodes_parsed[i];

     float     rel = abs * 100.0F / total;

     float   nodes = _bytecodes_parsed[i] == 0 ? 0 : (1.0F * _nodes_constructed[i])/_bytecodes_parsed[i];

     float  rnodes = _bytecodes_parsed[i] == 0 ? 0 :  rel * nodes;

     float  xforms = _bytecodes_parsed[i] == 0 ? 0 : (1.0F * _nodes_transformed[i])/_bytecodes_parsed[i];

     float  values = _bytecodes_parsed[i] == 0 ? 0 : (1.0F * _new_values       [i])/_bytecodes_parsed[i];

     if (cutoff <= rel) {

       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));

       abs_sum += abs;

     }

   }

   tty->print_cr("----------------------------------------------------------------------");

   float rel_sum = abs_sum * 100.0F / total;

   tty->print_cr("%10d  %7.2f%%    (cutoff = %.2f%%)", abs_sum, rel_sum, cutoff);

   tty->print_cr("----------------------------------------------------------------------");

   tty->cr();

 }

 #endif

 //----------------------------load_state_from----------------------------------

 // Load block/map/sp.  But not do not touch iter/bci.

 void Parse::load_state_from(Block* block) {

   set_block(block);

   // load the block's JVM state:

   set_map(block->start_map());

   set_sp( block->start_sp());

 }

 //-----------------------------record_state------------------------------------

 void Parse::Block::record_state(Parse* p) {

   assert(!is_merged(), "can only record state once, on 1st inflow");

   assert(start_sp() == p->sp(), "stack pointer must agree with ciTypeFlow");

   set_start_map(p->stop());

 }

 //------------------------------do_one_block-----------------------------------

 void Parse::do_one_block() {

   if (TraceOptoParse) {

     Block *b = block();

     int ns = b->num_successors();

     int nt = b->all_successors();

     tty->print("Parsing block #%d at bci [%d,%d), successors: ",

                   block()->rpo(), block()->start(), block()->limit());

     for (int i = 0; i < nt; i++) {

       tty->print((( i < ns) ? " %d" : " %d(e)"), b->successor_at(i)->rpo());

     }

     if (b->is_loop_head()) tty->print("  lphd");

     tty->cr();

   }

   assert(block()->is_merged(), "must be merged before being parsed");

   block()->mark_parsed();

   ++_blocks_parsed;

   // Set iterator to start of block.

   iter().reset_to_bci(block()->start());

   CompileLog* log = C->log();

   // Parse bytecodes

   while (!stopped() && !failing()) {

     iter().next();

     // Learn the current bci from the iterator:

     set_parse_bci(iter().cur_bci());

     if (bci() == block()->limit()) {

       // Do not walk into the next block until directed by do_all_blocks.

       merge(bci());

       break;

     }

     assert(bci() < block()->limit(), "bci still in block");

     if (log != NULL) {

       // Output an optional context marker, to help place actions

       // that occur during parsing of this BC.  If there is no log

       // output until the next context string, this context string

       // will be silently ignored.

       log->set_context("bc code='%d' bci='%d'", (int)bc(), bci());

     }

     if (block()->has_trap_at(bci())) {

       // We must respect the flow pass's traps, because it will refuse

       // to produce successors for trapping blocks.

       int trap_index = block()->flow()->trap_index();

       assert(trap_index != 0, "trap index must be valid");

       uncommon_trap(trap_index);

       break;

     }

     NOT_PRODUCT( parse_histogram()->set_initial_state(bc()); );

 #ifdef ASSERT

     int pre_bc_sp = sp();

     int inputs, depth;

     bool have_se = !stopped() && compute_stack_effects(inputs, depth);

     assert(!have_se || pre_bc_sp >= inputs, err_msg_res("have enough stack to execute this BC: pre_bc_sp=%d, inputs=%d", pre_bc_sp, inputs));

 #endif //ASSERT

     do_one_bytecode();

     assert(!have_se || stopped() || failing() || (sp() - pre_bc_sp) == depth,

            err_msg_res("incorrect depth prediction: sp=%d, pre_bc_sp=%d, depth=%d", sp(), pre_bc_sp, depth));

     do_exceptions();

     NOT_PRODUCT( parse_histogram()->record_change(); );

     if (log != NULL)

       log->clear_context();  // skip marker if nothing was printed

     // Fall into next bytecode.  Each bytecode normally has 1 sequential

     // successor which is typically made ready by visiting this bytecode.

     // If the successor has several predecessors, then it is a merge

     // point, starts a new basic block, and is handled like other basic blocks.

   }

 }

 //------------------------------merge------------------------------------------

 void Parse::set_parse_bci(int bci) {

   set_bci(bci);

   Node_Notes* nn = C->default_node_notes();

   if (nn == NULL)  return;

   // Collect debug info for inlined calls unless -XX:-DebugInlinedCalls.

   if (!DebugInlinedCalls && depth() > 1) {

     return;

   }

   // Update the JVMS annotation, if present.

   JVMState* jvms = nn->jvms();

   if (jvms != NULL && jvms->bci() != bci) {

     // Update the JVMS.

     jvms = jvms->clone_shallow(C);

     jvms->set_bci(bci);

     nn->set_jvms(jvms);

   }

 }

 //------------------------------merge------------------------------------------

 // Merge the current mapping into the basic block starting at bci

 void Parse::merge(int target_bci) {

   Block* target = successor_for_bci(target_bci);

   if (target == NULL) { handle_missing_successor(target_bci); return; }

   assert(!target->is_ready(), "our arrival must be expected");

   int pnum = target->next_path_num();

   merge_common(target, pnum);

 }

 //-------------------------merge_new_path--------------------------------------

 // Merge the current mapping into the basic block, using a new path

 void Parse::merge_new_path(int target_bci) {

   Block* target = successor_for_bci(target_bci);

   if (target == NULL) { handle_missing_successor(target_bci); return; }

   assert(!target->is_ready(), "new path into frozen graph");

   int pnum = target->add_new_path();

   merge_common(target, pnum);

 }

 //-------------------------merge_exception-------------------------------------

 // Merge the current mapping into the basic block starting at bci

 // The ex_oop must be pushed on the stack, unlike throw_to_exit.

 void Parse::merge_exception(int target_bci) {

   assert(sp() == 1, "must have only the throw exception on the stack");

   Block* target = successor_for_bci(target_bci);

   if (target == NULL) { handle_missing_successor(target_bci); return; }

   assert(target->is_handler(), "exceptions are handled by special blocks");

   int pnum = target->add_new_path();

   merge_common(target, pnum);

 }

 //--------------------handle_missing_successor---------------------------------

 void Parse::handle_missing_successor(int target_bci) {

 #ifndef PRODUCT

   Block* b = block();

   int trap_bci = b->flow()->has_trap()? b->flow()->trap_bci(): -1;

   tty->print_cr("### Missing successor at bci:%d for block #%d (trap_bci:%d)", target_bci, b->rpo(), trap_bci);

 #endif

   ShouldNotReachHere();

 }

 //--------------------------merge_common---------------------------------------

 void Parse::merge_common(Parse::Block* target, int pnum) {

   if (TraceOptoParse) {

     tty->print("Merging state at block #%d bci:%d", target->rpo(), target->start());

   }

   // Zap extra stack slots to top

   assert(sp() == target->start_sp(), "");

   clean_stack(sp());

   if (!target->is_merged()) {   // No prior mapping at this bci

     if (TraceOptoParse) { tty->print(" with empty state");  }

     // If this path is dead, do not bother capturing it as a merge.

     // It is "as if" we had 1 fewer predecessors from the beginning.

     if (stopped()) {

       if (TraceOptoParse)  tty->print_cr(", but path is dead and doesn't count");

       return;

     }

     // Record that a new block has been merged.

     ++_blocks_merged;

     // Make a region if we know there are multiple or unpredictable inputs.

     // (Also, if this is a plain fall-through, we might see another region,

     // which must not be allowed into this block's map.)

     if (pnum > PhiNode::Input         // Known multiple inputs.

         || target->is_handler()       // These have unpredictable inputs.

         || target->is_loop_head()     // Known multiple inputs

         || control()->is_Region()) {  // We must hide this guy.

       int current_bci = bci();

       set_parse_bci(target->start()); // Set target bci

       if (target->is_SEL_head()) {

         DEBUG_ONLY( target->mark_merged_backedge(block()); )

         if (target->start() == 0) {

           // Add loop predicate for the special case when

           // there are backbranches to the method entry.

           add_predicate();

         }

       }

       // Add a Region to start the new basic block.  Phis will be added

       // later lazily.

       int edges = target->pred_count();

       if (edges < pnum)  edges = pnum;  // might be a new path!

       RegionNode *r = new (C) RegionNode(edges+1);

       gvn().set_type(r, Type::CONTROL);

       record_for_igvn(r);

       // zap all inputs to NULL for debugging (done in Node(uint) constructor)

       // for (int j = 1; j < edges+1; j++) { r->init_req(j, NULL); }

       r->init_req(pnum, control());

       set_control(r);

       set_parse_bci(current_bci); // Restore bci

     }

     // Convert the existing Parser mapping into a mapping at this bci.

     store_state_to(target);

     assert(target->is_merged(), "do not come here twice");

   } else {                      // Prior mapping at this bci

     if (TraceOptoParse) {  tty->print(" with previous state"); }

 #ifdef ASSERT

     if (target->is_SEL_head()) {

       target->mark_merged_backedge(block());

     }

 #endif

     // We must not manufacture more phis if the target is already parsed.

     bool nophi = target->is_parsed();

     SafePointNode* newin = map();// Hang on to incoming mapping

     Block* save_block = block(); // Hang on to incoming block;

     load_state_from(target);    // Get prior mapping

     assert(newin->jvms()->locoff() == jvms()->locoff(), "JVMS layouts agree");

     assert(newin->jvms()->stkoff() == jvms()->stkoff(), "JVMS layouts agree");

     assert(newin->jvms()->monoff() == jvms()->monoff(), "JVMS layouts agree");

     assert(newin->jvms()->endoff() == jvms()->endoff(), "JVMS layouts agree");

     // Iterate over my current mapping and the old mapping.

     // Where different, insert Phi functions.

     // Use any existing Phi functions.

     assert(control()->is_Region(), "must be merging to a region");

     RegionNode* r = control()->as_Region();

     // Compute where to merge into

     // Merge incoming control path

     r->init_req(pnum, newin->control());

     if (pnum == 1) {            // Last merge for this Region?

       if (!block()->flow()->is_irreducible_entry()) {

         Node* result = _gvn.transform_no_reclaim(r);

         if (r != result && TraceOptoParse) {

           tty->print_cr("Block #%d replace %d with %d", block()->rpo(), r->_idx, result->_idx);

         }

       }

       record_for_igvn(r);

     }

     // Update all the non-control inputs to map:

     assert(TypeFunc::Parms == newin->jvms()->locoff(), "parser map should contain only youngest jvms");

     bool check_elide_phi = target->is_SEL_backedge(save_block);

     for (uint j = 1; j < newin->req(); j++) {

       Node* m = map()->in(j);   // Current state of target.

       Node* n = newin->in(j);   // Incoming change to target state.

       PhiNode* phi;

       if (m->is_Phi() && m->as_Phi()->region() == r)

         phi = m->as_Phi();

       else

         phi = NULL;

       if (m != n) {             // Different; must merge

         switch (j) {

         // Frame pointer and Return Address never changes

         case TypeFunc::FramePtr:// Drop m, use the original value

         case TypeFunc::ReturnAdr:

           break;

         case TypeFunc::Memory:  // Merge inputs to the MergeMem node

           assert(phi == NULL, "the merge contains phis, not vice versa");

           merge_memory_edges(n->as_MergeMem(), pnum, nophi);

           continue;

         default:                // All normal stuff

           if (phi == NULL) {

             const JVMState* jvms = map()->jvms();

             if (EliminateNestedLocks &&

                 jvms->is_mon(j) && jvms->is_monitor_box(j)) {

               // BoxLock nodes are not commoning.

               // Use old BoxLock node as merged box.

               assert(newin->jvms()->is_monitor_box(j), "sanity");

               // This assert also tests that nodes are BoxLock.

               assert(BoxLockNode::same_slot(n, m), "sanity");

               C->gvn_replace_by(n, m);

             } else if (!check_elide_phi || !target->can_elide_SEL_phi(j)) {

               phi = ensure_phi(j, nophi);

             }

           }

           break;

         }

       }

       // At this point, n might be top if:

       //  - there is no phi (because TypeFlow detected a conflict), or

       //  - the corresponding control edges is top (a dead incoming path)

       // It is a bug if we create a phi which sees a garbage value on a live path.

       if (phi != NULL) {

         assert(n != top() || r->in(pnum) == top(), "live value must not be garbage");

         assert(phi->region() == r, "");

         phi->set_req(pnum, n);  // Then add 'n' to the merge

         if (pnum == PhiNode::Input) {

           // Last merge for this Phi.

           // So far, Phis have had a reasonable type from ciTypeFlow.

           // Now _gvn will join that with the meet of current inputs.

           // BOTTOM is never permissible here, 'cause pessimistically

           // Phis of pointers cannot lose the basic pointer type.

           debug_only(const Type* bt1 = phi->bottom_type());

           assert(bt1 != Type::BOTTOM, "should not be building conflict phis");

           map()->set_req(j, _gvn.transform_no_reclaim(phi));

           debug_only(const Type* bt2 = phi->bottom_type());

           assert(bt2->higher_equal_speculative(bt1), "must be consistent with type-flow");

           record_for_igvn(phi);

         }

       }

     } // End of for all values to be merged

     if (pnum == PhiNode::Input &&

         !r->in(0)) {         // The occasional useless Region

       assert(control() == r, "");

       set_control(r->nonnull_req());

     }

     map()->merge_replaced_nodes_with(newin);

     // newin has been subsumed into the lazy merge, and is now dead.

     set_block(save_block);

     stop();                     // done with this guy, for now

   }

   if (TraceOptoParse) {

     tty->print_cr(" on path %d", pnum);

   }

   // Done with this parser state.

   assert(stopped(), "");

 }

 //--------------------------merge_memory_edges---------------------------------

 void Parse::merge_memory_edges(MergeMemNode* n, int pnum, bool nophi) {

   // (nophi means we must not create phis, because we already parsed here)

   assert(n != NULL, "");

   // Merge the inputs to the MergeMems

   MergeMemNode* m = merged_memory();

   assert(control()->is_Region(), "must be merging to a region");

   RegionNode* r = control()->as_Region();

   PhiNode* base = NULL;

   MergeMemNode* remerge = NULL;

   for (MergeMemStream mms(m, n); mms.next_non_empty2(); ) {

     Node *p = mms.force_memory();

     Node *q = mms.memory2();

     if (mms.is_empty() && nophi) {

       // Trouble:  No new splits allowed after a loop body is parsed.

       // Instead, wire the new split into a MergeMem on the backedge.

       // The optimizer will sort it out, slicing the phi.

       if (remerge == NULL) {

         assert(base != NULL, "");

         assert(base->in(0) != NULL, "should not be xformed away");

         remerge = MergeMemNode::make(C, base->in(pnum));

         gvn().set_type(remerge, Type::MEMORY);

         base->set_req(pnum, remerge);

       }

       remerge->set_memory_at(mms.alias_idx(), q);

       continue;

     }

     assert(!q->is_MergeMem(), "");

     PhiNode* phi;

     if (p != q) {

       phi = ensure_memory_phi(mms.alias_idx(), nophi);

     } else {

       if (p->is_Phi() && p->as_Phi()->region() == r)

         phi = p->as_Phi();

       else

         phi = NULL;

     }

     // Insert q into local phi

     if (phi != NULL) {

       assert(phi->region() == r, "");

       p = phi;

       phi->set_req(pnum, q);

       if (mms.at_base_memory()) {

         base = phi;  // delay transforming it

       } else if (pnum == 1) {

         record_for_igvn(phi);

         p = _gvn.transform_no_reclaim(phi);

       }

       mms.set_memory(p);// store back through the iterator

     }

   }

   // Transform base last, in case we must fiddle with remerging.

   if (base != NULL && pnum == 1) {

     record_for_igvn(base);

     m->set_base_memory( _gvn.transform_no_reclaim(base) );

   }

 }

 //------------------------ensure_phis_everywhere-------------------------------

 void Parse::ensure_phis_everywhere() {

   ensure_phi(TypeFunc::I_O);

   // Ensure a phi on all currently known memories.

   for (MergeMemStream mms(merged_memory()); mms.next_non_empty(); ) {

     ensure_memory_phi(mms.alias_idx());

     debug_only(mms.set_memory());  // keep the iterator happy

   }

   // Note:  This is our only chance to create phis for memory slices.

   // If we miss a slice that crops up later, it will have to be

   // merged into the base-memory phi that we are building here.

   // Later, the optimizer will comb out the knot, and build separate

   // phi-loops for each memory slice that matters.

   // Monitors must nest nicely and not get confused amongst themselves.

   // Phi-ify everything up to the monitors, though.

   uint monoff = map()->jvms()->monoff();

   uint nof_monitors = map()->jvms()->nof_monitors();

   assert(TypeFunc::Parms == map()->jvms()->locoff(), "parser map should contain only youngest jvms");

   bool check_elide_phi = block()->is_SEL_head();

   for (uint i = TypeFunc::Parms; i < monoff; i++) {

     if (!check_elide_phi || !block()->can_elide_SEL_phi(i)) {

       ensure_phi(i);

     }

   }

   // Even monitors need Phis, though they are well-structured.

   // This is true for OSR methods, and also for the rare cases where

   // a monitor object is the subject of a replace_in_map operation.

   // See bugs 4426707 and 5043395.

   for (uint m = 0; m < nof_monitors; m++) {

     ensure_phi(map()->jvms()->monitor_obj_offset(m));

   }

 }

 //-----------------------------add_new_path------------------------------------

 // Add a previously unaccounted predecessor to this block.

 int Parse::Block::add_new_path() {

   // If there is no map, return the lowest unused path number.

   if (!is_merged())  return pred_count()+1;  // there will be a map shortly

   SafePointNode* map = start_map();

   if (!map->control()->is_Region())

     return pred_count()+1;  // there may be a region some day

   RegionNode* r = map->control()->as_Region();

   // Add new path to the region.

   uint pnum = r->req();

   r->add_req(NULL);

   for (uint i = 1; i < map->req(); i++) {

     Node* n = map->in(i);

     if (i == TypeFunc::Memory) {

       // Ensure a phi on all currently known memories.

       for (MergeMemStream mms(n->as_MergeMem()); mms.next_non_empty(); ) {

         Node* phi = mms.memory();

         if (phi->is_Phi() && phi->as_Phi()->region() == r) {

           assert(phi->req() == pnum, "must be same size as region");

           phi->add_req(NULL);

         }

       }

     } else {

       if (n->is_Phi() && n->as_Phi()->region() == r) {

         assert(n->req() == pnum, "must be same size as region");

         n->add_req(NULL);

       }

     }

   }

   return pnum;

 }

 //------------------------------ensure_phi-------------------------------------

 // Turn the idx'th entry of the current map into a Phi

 PhiNode *Parse::ensure_phi(int idx, bool nocreate) {

   SafePointNode* map = this->map();

   Node* region = map->control();

   assert(region->is_Region(), "");

   Node* o = map->in(idx);

   assert(o != NULL, "");

   if (o == top())  return NULL; // TOP always merges into TOP

   if (o->is_Phi() && o->as_Phi()->region() == region) {

     return o->as_Phi();

   }

   // Now use a Phi here for merging

   assert(!nocreate, "Cannot build a phi for a block already parsed.");

   const JVMState* jvms = map->jvms();

   const Type* t = NULL;

   if (jvms->is_loc(idx)) {

     t = block()->local_type_at(idx - jvms->locoff());

   } else if (jvms->is_stk(idx)) {

     t = block()->stack_type_at(idx - jvms->stkoff());

   } else if (jvms->is_mon(idx)) {

     assert(!jvms->is_monitor_box(idx), "no phis for boxes");

     t = TypeInstPtr::BOTTOM; // this is sufficient for a lock object

   } else if ((uint)idx < TypeFunc::Parms) {

     t = o->bottom_type();  // Type::RETURN_ADDRESS or such-like.

   } else {

     assert(false, "no type information for this phi");

   }

   // If the type falls to bottom, then this must be a local that

   // is mixing ints and oops or some such.  Forcing it to top

   // makes it go dead.

   if (t == Type::BOTTOM) {

     map->set_req(idx, top());

     return NULL;

   }

   // Do not create phis for top either.

   // A top on a non-null control flow must be an unused even after the.phi.

   if (t == Type::TOP || t == Type::HALF) {

     map->set_req(idx, top());

     return NULL;

   }

   PhiNode* phi = PhiNode::make(region, o, t);

   gvn().set_type(phi, t);

   if (C->do_escape_analysis()) record_for_igvn(phi);

   map->set_req(idx, phi);

   return phi;

 }

 //--------------------------ensure_memory_phi----------------------------------

 // Turn the idx'th slice of the current memory into a Phi

 PhiNode *Parse::ensure_memory_phi(int idx, bool nocreate) {

   MergeMemNode* mem = merged_memory();

   Node* region = control();

   assert(region->is_Region(), "");

   Node *o = (idx == Compile::AliasIdxBot)? mem->base_memory(): mem->memory_at(idx);

   assert(o != NULL && o != top(), "");

   PhiNode* phi;

   if (o->is_Phi() && o->as_Phi()->region() == region) {

     phi = o->as_Phi();

     if (phi == mem->base_memory() && idx >= Compile::AliasIdxRaw) {

       // clone the shared base memory phi to make a new memory split

       assert(!nocreate, "Cannot build a phi for a block already parsed.");

       const Type* t = phi->bottom_type();

       const TypePtr* adr_type = C->get_adr_type(idx);

       phi = phi->slice_memory(adr_type);

       gvn().set_type(phi, t);

     }

     return phi;

   }

   // Now use a Phi here for merging

   assert(!nocreate, "Cannot build a phi for a block already parsed.");

   const Type* t = o->bottom_type();

   const TypePtr* adr_type = C->get_adr_type(idx);

   phi = PhiNode::make(region, o, t, adr_type);

   gvn().set_type(phi, t);

   if (idx == Compile::AliasIdxBot)

     mem->set_base_memory(phi);

   else

     mem->set_memory_at(idx, phi);

   return phi;

 }

 //------------------------------call_register_finalizer-----------------------

 // Check the klass of the receiver and call register_finalizer if the

 // class need finalization.

 void Parse::call_register_finalizer() {

   Node* receiver = local(0);

   assert(receiver != NULL && receiver->bottom_type()->isa_instptr() != NULL,

          "must have non-null instance type");

   const TypeInstPtr *tinst = receiver->bottom_type()->isa_instptr();

   if (tinst != NULL && tinst->klass()->is_loaded() && !tinst->klass_is_exact()) {

     // The type isn't known exactly so see if CHA tells us anything.

     ciInstanceKlass* ik = tinst->klass()->as_instance_klass();

     if (!Dependencies::has_finalizable_subclass(ik)) {

       // No finalizable subclasses so skip the dynamic check.

       C->dependencies()->assert_has_no_finalizable_subclasses(ik);

       return;

     }

   }

   // Insert a dynamic test for whether the instance needs

   // finalization.  In general this will fold up since the concrete

   // class is often visible so the access flags are constant.

   Node* klass_addr = basic_plus_adr( receiver, receiver, oopDesc::klass_offset_in_bytes() );

   Node* klass = _gvn.transform(LoadKlassNode::make(_gvn, NULL, immutable_memory(), klass_addr, TypeInstPtr::KLASS));

   Node* access_flags_addr = basic_plus_adr(klass, klass, in_bytes(Klass::access_flags_offset()));

   Node* access_flags = make_load(NULL, access_flags_addr, TypeInt::INT, T_INT, MemNode::unordered);

   Node* mask  = _gvn.transform(new (C) AndINode(access_flags, intcon(JVM_ACC_HAS_FINALIZER)));

   Node* check = _gvn.transform(new (C) CmpINode(mask, intcon(0)));

   Node* test  = _gvn.transform(new (C) BoolNode(check, BoolTest::ne));

   IfNode* iff = create_and_map_if(control(), test, PROB_MAX, COUNT_UNKNOWN);

   RegionNode* result_rgn = new (C) RegionNode(3);

   record_for_igvn(result_rgn);

   Node *skip_register = _gvn.transform(new (C) IfFalseNode(iff));

   result_rgn->init_req(1, skip_register);

   Node *needs_register = _gvn.transform(new (C) IfTrueNode(iff));

   set_control(needs_register);

   if (stopped()) {

     // There is no slow path.

     result_rgn->init_req(2, top());

   } else {

     Node *call = make_runtime_call(RC_NO_LEAF,

                                    OptoRuntime::register_finalizer_Type(),

                                    OptoRuntime::register_finalizer_Java(),

                                    NULL, TypePtr::BOTTOM,

                                    receiver);

     make_slow_call_ex(call, env()->Throwable_klass(), true);

     Node* fast_io  = call->in(TypeFunc::I_O);

     Node* fast_mem = call->in(TypeFunc::Memory);

     // These two phis are pre-filled with copies of of the fast IO and Memory

     Node* io_phi   = PhiNode::make(result_rgn, fast_io,  Type::ABIO);

     Node* mem_phi  = PhiNode::make(result_rgn, fast_mem, Type::MEMORY, TypePtr::BOTTOM);

     result_rgn->init_req(2, control());

     io_phi    ->init_req(2, i_o());

     mem_phi   ->init_req(2, reset_memory());

     set_all_memory( _gvn.transform(mem_phi) );

     set_i_o(        _gvn.transform(io_phi) );

   }

   set_control( _gvn.transform(result_rgn) );

 }

 // Add check to deoptimize if RTM state is not ProfileRTM

 void Parse::rtm_deopt() {

 #if INCLUDE_RTM_OPT

   if (C->profile_rtm()) {

     assert(C->method() != NULL, "only for normal compilations");

     assert(!C->method()->method_data()->is_empty(), "MDO is needed to record RTM state");

     assert(depth() == 1, "generate check only for main compiled method");

     // Set starting bci for uncommon trap.

     set_parse_bci(is_osr_parse() ? osr_bci() : 0);

     // Load the rtm_state from the MethodData.

     const TypePtr* adr_type = TypeMetadataPtr::make(C->method()->method_data());

     Node* mdo = makecon(adr_type);

     int offset = MethodData::rtm_state_offset_in_bytes();

     Node* adr_node = basic_plus_adr(mdo, mdo, offset);

     Node* rtm_state = make_load(control(), adr_node, TypeInt::INT, T_INT, adr_type, MemNode::unordered);

     // Separate Load from Cmp by Opaque.

     // In expand_macro_nodes() it will be replaced either

     // with this load when there are locks in the code

     // or with ProfileRTM (cmp->in(2)) otherwise so that

     // the check will fold.

     Node* profile_state = makecon(TypeInt::make(ProfileRTM));

     Node* opq   = _gvn.transform( new (C) Opaque3Node(C, rtm_state, Opaque3Node::RTM_OPT) );

     Node* chk   = _gvn.transform( new (C) CmpINode(opq, profile_state) );

     Node* tst   = _gvn.transform( new (C) BoolNode(chk, BoolTest::eq) );

     // Branch to failure if state was changed

     { BuildCutout unless(this, tst, PROB_ALWAYS);

       uncommon_trap(Deoptimization::Reason_rtm_state_change,

                     Deoptimization::Action_make_not_entrant);

     }

   }

 #endif

 }

 //------------------------------return_current---------------------------------

 // Append current _map to _exit_return

 void Parse::return_current(Node* value) {

   if (RegisterFinalizersAtInit &&

       method()->intrinsic_id() == vmIntrinsics::_Object_init) {

     call_register_finalizer();

   }

   // Do not set_parse_bci, so that return goo is credited to the return insn.

   set_bci(InvocationEntryBci);

   if (method()->is_synchronized() && GenerateSynchronizationCode) {

     shared_unlock(_synch_lock->box_node(), _synch_lock->obj_node());

   }

   if (C->env()->dtrace_method_probes()) {

     make_dtrace_method_exit(method());

   }

   SafePointNode* exit_return = _exits.map();

   exit_return->in( TypeFunc::Control  )->add_req( control() );

   exit_return->in( TypeFunc::I_O      )->add_req( i_o    () );

   Node *mem = exit_return->in( TypeFunc::Memory   );

   for (MergeMemStream mms(mem->as_MergeMem(), merged_memory()); mms.next_non_empty2(); ) {

     if (mms.is_empty()) {

       // get a copy of the base memory, and patch just this one input

       const TypePtr* adr_type = mms.adr_type(C);

       Node* phi = mms.force_memory()->as_Phi()->slice_memory(adr_type);

       assert(phi->as_Phi()->region() == mms.base_memory()->in(0), "");

       gvn().set_type_bottom(phi);

       phi->del_req(phi->req()-1);  // prepare to re-patch

       mms.set_memory(phi);

     }

     mms.memory()->add_req(mms.memory2());

   }

   // frame pointer is always same, already captured

   if (value != NULL) {

     // If returning oops to an interface-return, there is a silent free

     // cast from oop to interface allowed by the Verifier.  Make it explicit

     // here.

     Node* phi = _exits.argument(0);

     const TypeInstPtr *tr = phi->bottom_type()->isa_instptr();

     if (tr && tr->klass()->is_loaded() &&

         tr->klass()->is_interface()) {

       const TypeInstPtr *tp = value->bottom_type()->isa_instptr();

       if (tp && tp->klass()->is_loaded() &&

           !tp->klass()->is_interface()) {

         // sharpen the type eagerly; this eases certain assert checking

         if (tp->higher_equal(TypeInstPtr::NOTNULL))

           tr = tr->join_speculative(TypeInstPtr::NOTNULL)->is_instptr();

         value = _gvn.transform(new (C) CheckCastPPNode(0, value, tr));

       }

     } else {

       // Also handle returns of oop-arrays to an arrays-of-interface return

       const TypeInstPtr* phi_tip;

       const TypeInstPtr* val_tip;

       Type::get_arrays_base_elements(phi->bottom_type(), value->bottom_type(), &phi_tip, &val_tip);

       if (phi_tip != NULL && phi_tip->is_loaded() && phi_tip->klass()->is_interface() &&

           val_tip != NULL && val_tip->is_loaded() && !val_tip->klass()->is_interface()) {

          value = _gvn.transform(new (C) CheckCastPPNode(0, value, phi->bottom_type()));

       }

     }

     phi->add_req(value);

   }

   if (_first_return) {

     _exits.map()->transfer_replaced_nodes_from(map(), _new_idx);

     _first_return = false;

   } else {

     _exits.map()->merge_replaced_nodes_with(map());

   }

   stop_and_kill_map();          // This CFG path dies here

 }

 //------------------------------add_safepoint----------------------------------

 void Parse::add_safepoint() {

   // See if we can avoid this safepoint.  No need for a SafePoint immediately

   // after a Call (except Leaf Call) or another SafePoint.

   Node *proj = control();

   bool add_poll_param = SafePointNode::needs_polling_address_input();

   uint parms = add_poll_param ? TypeFunc::Parms+1 : TypeFunc::Parms;

   if( proj->is_Proj() ) {

     Node *n0 = proj->in(0);

     if( n0->is_Catch() ) {

       n0 = n0->in(0)->in(0);

       assert( n0->is_Call(), "expect a call here" );

     }

     if( n0->is_Call() ) {

       if( n0->as_Call()->guaranteed_safepoint() )

         return;

     } else if( n0->is_SafePoint() && n0->req() >= parms ) {

       return;

     }

   }

   // Clear out dead values from the debug info.

   kill_dead_locals();

   // Clone the JVM State

   SafePointNode *sfpnt = new (C) SafePointNode(parms, NULL);

   // Capture memory state BEFORE a SafePoint.  Since we can block at a

   // SafePoint we need our GC state to be safe; i.e. we need all our current

   // write barriers (card marks) to not float down after the SafePoint so we

   // must read raw memory.  Likewise we need all oop stores to match the card

   // marks.  If deopt can happen, we need ALL stores (we need the correct JVM

   // state on a deopt).

   // We do not need to WRITE the memory state after a SafePoint.  The control

   // edge will keep card-marks and oop-stores from floating up from below a

   // SafePoint and our true dependency added here will keep them from floating

   // down below a SafePoint.

   // Clone the current memory state

   Node* mem = MergeMemNode::make(C, map()->memory());

   mem = _gvn.transform(mem);

   // Pass control through the safepoint

   sfpnt->init_req(TypeFunc::Control  , control());

   // Fix edges normally used by a call

   sfpnt->init_req(TypeFunc::I_O      , top() );

   sfpnt->init_req(TypeFunc::Memory   , mem   );

   sfpnt->init_req(TypeFunc::ReturnAdr, top() );

   sfpnt->init_req(TypeFunc::FramePtr , top() );

   // Create a node for the polling address

   if( add_poll_param ) {

     Node *polladr = ConPNode::make(C, (address)os::get_polling_page());

     sfpnt->init_req(TypeFunc::Parms+0, _gvn.transform(polladr));

   }

   // Fix up the JVM State edges

   add_safepoint_edges(sfpnt);

   Node *transformed_sfpnt = _gvn.transform(sfpnt);

   set_control(transformed_sfpnt);

   // Provide an edge from root to safepoint.  This makes the safepoint

   // appear useful until the parse has completed.

   if( OptoRemoveUseless && transformed_sfpnt->is_SafePoint() ) {

     assert(C->root() != NULL, "Expect parse is still valid");

     C->root()->add_prec(transformed_sfpnt);

   }

 }

 #ifndef PRODUCT

 //------------------------show_parse_info--------------------------------------

 void Parse::show_parse_info() {

   InlineTree* ilt = NULL;

   if (C->ilt() != NULL) {

     JVMState* caller_jvms = is_osr_parse() ? caller()->caller() : caller();

     ilt = InlineTree::find_subtree_from_root(C->ilt(), caller_jvms, method());

   }

   if (PrintCompilation && Verbose) {

     if (depth() == 1) {

       if( ilt->count_inlines() ) {

         tty->print("    __inlined %d (%d bytes)", ilt->count_inlines(),

                      ilt->count_inline_bcs());

         tty->cr();

       }

     } else {

       if (method()->is_synchronized())         tty->print("s");

       if (method()->has_exception_handlers())  tty->print("!");

       // Check this is not the final compiled version

       if (C->trap_can_recompile()) {

         tty->print("-");

       } else {

         tty->print(" ");

       }

       method()->print_short_name();

       if (is_osr_parse()) {

         tty->print(" @ %d", osr_bci());

       }

       tty->print(" (%d bytes)",method()->code_size());

       if (ilt->count_inlines()) {

         tty->print(" __inlined %d (%d bytes)", ilt->count_inlines(),

                    ilt->count_inline_bcs());

       }

       tty->cr();

     }

   }

   if (PrintOpto && (depth() == 1 || PrintOptoInlining)) {

     // Print that we succeeded; suppress this message on the first osr parse.

     if (method()->is_synchronized())         tty->print("s");

     if (method()->has_exception_handlers())  tty->print("!");

     // Check this is not the final compiled version

     if (C->trap_can_recompile() && depth() == 1) {

       tty->print("-");

     } else {

       tty->print(" ");

     }

     if( depth() != 1 ) { tty->print("   "); }  // missing compile count

     for (int i = 1; i < depth(); ++i) { tty->print("  "); }

     method()->print_short_name();

     if (is_osr_parse()) {

       tty->print(" @ %d", osr_bci());

     }

     if (ilt->caller_bci() != -1) {

       tty->print(" @ %d", ilt->caller_bci());

     }

     tty->print(" (%d bytes)",method()->code_size());

     if (ilt->count_inlines()) {

       tty->print(" __inlined %d (%d bytes)", ilt->count_inlines(),

                  ilt->count_inline_bcs());

     }

     tty->cr();

   }

 }

 //------------------------------dump-------------------------------------------

 // Dump information associated with the bytecodes of current _method

 void Parse::dump() {

   if( method() != NULL ) {

     // Iterate over bytecodes

     ciBytecodeStream iter(method());

     for( Bytecodes::Code bc = iter.next(); bc != ciBytecodeStream::EOBC() ; bc = iter.next() ) {

       dump_bci( iter.cur_bci() );

       tty->cr();

     }

   }

 }

 // Dump information associated with a byte code index, 'bci'

 void Parse::dump_bci(int bci) {

   // Output info on merge-points, cloning, and within _jsr..._ret

   // NYI

   tty->print(" bci:%d", bci);

 }

 #endif