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

 /*

  * Copyright 2001-2008 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

  * CA 95054 USA or visit www.sun.com if you need additional information or

  * have any questions.

  *

  */

 #include "incls/_precompiled.incl"

 #include "incls/_graphKit.cpp.incl"

 //----------------------------GraphKit-----------------------------------------

 // Main utility constructor.

 GraphKit::GraphKit(JVMState* jvms)

   : Phase(Phase::Parser),

     _env(C->env()),

     _gvn(*C->initial_gvn())

 {

   _exceptions = jvms->map()->next_exception();

   if (_exceptions != NULL)  jvms->map()->set_next_exception(NULL);

   set_jvms(jvms);

 }

 // Private constructor for parser.

 GraphKit::GraphKit()

   : Phase(Phase::Parser),

     _env(C->env()),

     _gvn(*C->initial_gvn())

 {

   _exceptions = NULL;

   set_map(NULL);

   debug_only(_sp = -99);

   debug_only(set_bci(-99));

 }

 //---------------------------clean_stack---------------------------------------

 // Clear away rubbish from the stack area of the JVM state.

 // This destroys any arguments that may be waiting on the stack.

 void GraphKit::clean_stack(int from_sp) {

   SafePointNode* map      = this->map();

   JVMState*      jvms     = this->jvms();

   int            stk_size = jvms->stk_size();

   int            stkoff   = jvms->stkoff();

   Node*          top      = this->top();

   for (int i = from_sp; i < stk_size; i++) {

     if (map->in(stkoff + i) != top) {

       map->set_req(stkoff + i, top);

     }

   }

 }

 //--------------------------------sync_jvms-----------------------------------

 // Make sure our current jvms agrees with our parse state.

 JVMState* GraphKit::sync_jvms() const {

   JVMState* jvms = this->jvms();

   jvms->set_bci(bci());       // Record the new bci in the JVMState

   jvms->set_sp(sp());         // Record the new sp in the JVMState

   assert(jvms_in_sync(), "jvms is now in sync");

   return jvms;

 }

 #ifdef ASSERT

 bool GraphKit::jvms_in_sync() const {

   Parse* parse = is_Parse();

   if (parse == NULL) {

     if (bci() !=      jvms()->bci())          return false;

     if (sp()  != (int)jvms()->sp())           return false;

     return true;

   }

   if (jvms()->method() != parse->method())    return false;

   if (jvms()->bci()    != parse->bci())       return false;

   int jvms_sp = jvms()->sp();

   if (jvms_sp          != parse->sp())        return false;

   int jvms_depth = jvms()->depth();

   if (jvms_depth       != parse->depth())     return false;

   return true;

 }

 // Local helper checks for special internal merge points

 // used to accumulate and merge exception states.

 // They are marked by the region's in(0) edge being the map itself.

 // Such merge points must never "escape" into the parser at large,

 // until they have been handed to gvn.transform.

 static bool is_hidden_merge(Node* reg) {

   if (reg == NULL)  return false;

   if (reg->is_Phi()) {

     reg = reg->in(0);

     if (reg == NULL)  return false;

   }

   return reg->is_Region() && reg->in(0) != NULL && reg->in(0)->is_Root();

 }

 void GraphKit::verify_map() const {

   if (map() == NULL)  return;  // null map is OK

   assert(map()->req() <= jvms()->endoff(), "no extra garbage on map");

   assert(!map()->has_exceptions(),    "call add_exception_states_from 1st");

   assert(!is_hidden_merge(control()), "call use_exception_state, not set_map");

 }

 void GraphKit::verify_exception_state(SafePointNode* ex_map) {

   assert(ex_map->next_exception() == NULL, "not already part of a chain");

   assert(has_saved_ex_oop(ex_map), "every exception state has an ex_oop");

 }

 #endif

 //---------------------------stop_and_kill_map---------------------------------

 // Set _map to NULL, signalling a stop to further bytecode execution.

 // First smash the current map's control to a constant, to mark it dead.

 void GraphKit::stop_and_kill_map() {

   SafePointNode* dead_map = stop();

   if (dead_map != NULL) {

     dead_map->disconnect_inputs(NULL); // Mark the map as killed.

     assert(dead_map->is_killed(), "must be so marked");

   }

 }

 //--------------------------------stopped--------------------------------------

 // Tell if _map is NULL, or control is top.

 bool GraphKit::stopped() {

   if (map() == NULL)           return true;

   else if (control() == top()) return true;

   else                         return false;

 }

 //-----------------------------has_ex_handler----------------------------------

 // Tell if this method or any caller method has exception handlers.

 bool GraphKit::has_ex_handler() {

   for (JVMState* jvmsp = jvms(); jvmsp != NULL; jvmsp = jvmsp->caller()) {

     if (jvmsp->has_method() && jvmsp->method()->has_exception_handlers()) {

       return true;

     }

   }

   return false;

 }

 //------------------------------save_ex_oop------------------------------------

 // Save an exception without blowing stack contents or other JVM state.

 void GraphKit::set_saved_ex_oop(SafePointNode* ex_map, Node* ex_oop) {

   assert(!has_saved_ex_oop(ex_map), "clear ex-oop before setting again");

   ex_map->add_req(ex_oop);

   debug_only(verify_exception_state(ex_map));

 }

 inline static Node* common_saved_ex_oop(SafePointNode* ex_map, bool clear_it) {

   assert(GraphKit::has_saved_ex_oop(ex_map), "ex_oop must be there");

   Node* ex_oop = ex_map->in(ex_map->req()-1);

   if (clear_it)  ex_map->del_req(ex_map->req()-1);

   return ex_oop;

 }

 //-----------------------------saved_ex_oop------------------------------------

 // Recover a saved exception from its map.

 Node* GraphKit::saved_ex_oop(SafePointNode* ex_map) {

   return common_saved_ex_oop(ex_map, false);

 }

 //--------------------------clear_saved_ex_oop---------------------------------

 // Erase a previously saved exception from its map.

 Node* GraphKit::clear_saved_ex_oop(SafePointNode* ex_map) {

   return common_saved_ex_oop(ex_map, true);

 }

 #ifdef ASSERT

 //---------------------------has_saved_ex_oop----------------------------------

 // Erase a previously saved exception from its map.

 bool GraphKit::has_saved_ex_oop(SafePointNode* ex_map) {

   return ex_map->req() == ex_map->jvms()->endoff()+1;

 }

 #endif

 //-------------------------make_exception_state--------------------------------

 // Turn the current JVM state into an exception state, appending the ex_oop.

 SafePointNode* GraphKit::make_exception_state(Node* ex_oop) {

   sync_jvms();

   SafePointNode* ex_map = stop();  // do not manipulate this map any more

   set_saved_ex_oop(ex_map, ex_oop);

   return ex_map;

 }

 //--------------------------add_exception_state--------------------------------

 // Add an exception to my list of exceptions.

 void GraphKit::add_exception_state(SafePointNode* ex_map) {

   if (ex_map == NULL || ex_map->control() == top()) {

     return;

   }

 #ifdef ASSERT

   verify_exception_state(ex_map);

   if (has_exceptions()) {

     assert(ex_map->jvms()->same_calls_as(_exceptions->jvms()), "all collected exceptions must come from the same place");

   }

 #endif

   // If there is already an exception of exactly this type, merge with it.

   // In particular, null-checks and other low-level exceptions common up here.

   Node*       ex_oop  = saved_ex_oop(ex_map);

   const Type* ex_type = _gvn.type(ex_oop);

   if (ex_oop == top()) {

     // No action needed.

     return;

   }

   assert(ex_type->isa_instptr(), "exception must be an instance");

   for (SafePointNode* e2 = _exceptions; e2 != NULL; e2 = e2->next_exception()) {

     const Type* ex_type2 = _gvn.type(saved_ex_oop(e2));

     // We check sp also because call bytecodes can generate exceptions

     // both before and after arguments are popped!

     if (ex_type2 == ex_type

         && e2->_jvms->sp() == ex_map->_jvms->sp()) {

       combine_exception_states(ex_map, e2);

       return;

     }

   }

   // No pre-existing exception of the same type.  Chain it on the list.

   push_exception_state(ex_map);

 }

 //-----------------------add_exception_states_from-----------------------------

 void GraphKit::add_exception_states_from(JVMState* jvms) {

   SafePointNode* ex_map = jvms->map()->next_exception();

   if (ex_map != NULL) {

     jvms->map()->set_next_exception(NULL);

     for (SafePointNode* next_map; ex_map != NULL; ex_map = next_map) {

       next_map = ex_map->next_exception();

       ex_map->set_next_exception(NULL);

       add_exception_state(ex_map);

     }

   }

 }

 //-----------------------transfer_exceptions_into_jvms-------------------------

 JVMState* GraphKit::transfer_exceptions_into_jvms() {

   if (map() == NULL) {

     // We need a JVMS to carry the exceptions, but the map has gone away.

     // Create a scratch JVMS, cloned from any of the exception states...

     if (has_exceptions()) {

       _map = _exceptions;

       _map = clone_map();

       _map->set_next_exception(NULL);

       clear_saved_ex_oop(_map);

       debug_only(verify_map());

     } else {

       // ...or created from scratch

       JVMState* jvms = new (C) JVMState(_method, NULL);

       jvms->set_bci(_bci);

       jvms->set_sp(_sp);

       jvms->set_map(new (C, TypeFunc::Parms) SafePointNode(TypeFunc::Parms, jvms));

       set_jvms(jvms);

       for (uint i = 0; i < map()->req(); i++)  map()->init_req(i, top());

       set_all_memory(top());

       while (map()->req() < jvms->endoff())  map()->add_req(top());

     }

     // (This is a kludge, in case you didn't notice.)

     set_control(top());

   }

   JVMState* jvms = sync_jvms();

   assert(!jvms->map()->has_exceptions(), "no exceptions on this map yet");

   jvms->map()->set_next_exception(_exceptions);

   _exceptions = NULL;   // done with this set of exceptions

   return jvms;

 }

 static inline void add_n_reqs(Node* dstphi, Node* srcphi) {

   assert(is_hidden_merge(dstphi), "must be a special merge node");

   assert(is_hidden_merge(srcphi), "must be a special merge node");

   uint limit = srcphi->req();

   for (uint i = PhiNode::Input; i < limit; i++) {

     dstphi->add_req(srcphi->in(i));

   }

 }

 static inline void add_one_req(Node* dstphi, Node* src) {

   assert(is_hidden_merge(dstphi), "must be a special merge node");

   assert(!is_hidden_merge(src), "must not be a special merge node");

   dstphi->add_req(src);

 }

 //-----------------------combine_exception_states------------------------------

 // This helper function combines exception states by building phis on a

 // specially marked state-merging region.  These regions and phis are

 // untransformed, and can build up gradually.  The region is marked by

 // having a control input of its exception map, rather than NULL.  Such

 // regions do not appear except in this function, and in use_exception_state.

 void GraphKit::combine_exception_states(SafePointNode* ex_map, SafePointNode* phi_map) {

   if (failing())  return;  // dying anyway...

   JVMState* ex_jvms = ex_map->_jvms;

   assert(ex_jvms->same_calls_as(phi_map->_jvms), "consistent call chains");

   assert(ex_jvms->stkoff() == phi_map->_jvms->stkoff(), "matching locals");

   assert(ex_jvms->sp() == phi_map->_jvms->sp(), "matching stack sizes");

   assert(ex_jvms->monoff() == phi_map->_jvms->monoff(), "matching JVMS");

   assert(ex_map->req() == phi_map->req(), "matching maps");

   uint tos = ex_jvms->stkoff() + ex_jvms->sp();

   Node*         hidden_merge_mark = root();

   Node*         region  = phi_map->control();

   MergeMemNode* phi_mem = phi_map->merged_memory();

   MergeMemNode* ex_mem  = ex_map->merged_memory();

   if (region->in(0) != hidden_merge_mark) {

     // The control input is not (yet) a specially-marked region in phi_map.

     // Make it so, and build some phis.

     region = new (C, 2) RegionNode(2);

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

     region->set_req(0, hidden_merge_mark);  // marks an internal ex-state

     region->init_req(1, phi_map->control());

     phi_map->set_control(region);

     Node* io_phi = PhiNode::make(region, phi_map->i_o(), Type::ABIO);

     record_for_igvn(io_phi);

     _gvn.set_type(io_phi, Type::ABIO);

     phi_map->set_i_o(io_phi);

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

       Node* m = mms.memory();

       Node* m_phi = PhiNode::make(region, m, Type::MEMORY, mms.adr_type(C));

       record_for_igvn(m_phi);

       _gvn.set_type(m_phi, Type::MEMORY);

       mms.set_memory(m_phi);

     }

   }

   // Either or both of phi_map and ex_map might already be converted into phis.

   Node* ex_control = ex_map->control();

   // if there is special marking on ex_map also, we add multiple edges from src

   bool add_multiple = (ex_control->in(0) == hidden_merge_mark);

   // how wide was the destination phi_map, originally?

   uint orig_width = region->req();

   if (add_multiple) {

     add_n_reqs(region, ex_control);

     add_n_reqs(phi_map->i_o(), ex_map->i_o());

   } else {

     // ex_map has no merges, so we just add single edges everywhere

     add_one_req(region, ex_control);

     add_one_req(phi_map->i_o(), ex_map->i_o());

   }

   for (MergeMemStream mms(phi_mem, ex_mem); mms.next_non_empty2(); ) {

     if (mms.is_empty()) {

       // get a copy of the base memory, and patch some inputs into it

       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), "");

       mms.set_memory(phi);

       // Prepare to append interesting stuff onto the newly sliced phi:

       while (phi->req() > orig_width)  phi->del_req(phi->req()-1);

     }

     // Append stuff from ex_map:

     if (add_multiple) {

       add_n_reqs(mms.memory(), mms.memory2());

     } else {

       add_one_req(mms.memory(), mms.memory2());

     }

   }

   uint limit = ex_map->req();

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

     // Skip everything in the JVMS after tos.  (The ex_oop follows.)

     if (i == tos)  i = ex_jvms->monoff();

     Node* src = ex_map->in(i);

     Node* dst = phi_map->in(i);

     if (src != dst) {

       PhiNode* phi;

       if (dst->in(0) != region) {

         dst = phi = PhiNode::make(region, dst, _gvn.type(dst));

         record_for_igvn(phi);

         _gvn.set_type(phi, phi->type());

         phi_map->set_req(i, dst);

         // Prepare to append interesting stuff onto the new phi:

         while (dst->req() > orig_width)  dst->del_req(dst->req()-1);

       } else {

         assert(dst->is_Phi(), "nobody else uses a hidden region");

         phi = (PhiNode*)dst;

       }

       if (add_multiple && src->in(0) == ex_control) {

         // Both are phis.

         add_n_reqs(dst, src);

       } else {

         while (dst->req() < region->req())  add_one_req(dst, src);

       }

       const Type* srctype = _gvn.type(src);

       if (phi->type() != srctype) {

         const Type* dsttype = phi->type()->meet(srctype);

         if (phi->type() != dsttype) {

           phi->set_type(dsttype);

           _gvn.set_type(phi, dsttype);

         }

       }

     }

   }

 }

 //--------------------------use_exception_state--------------------------------

 Node* GraphKit::use_exception_state(SafePointNode* phi_map) {

   if (failing()) { stop(); return top(); }

   Node* region = phi_map->control();

   Node* hidden_merge_mark = root();

   assert(phi_map->jvms()->map() == phi_map, "sanity: 1-1 relation");

   Node* ex_oop = clear_saved_ex_oop(phi_map);

   if (region->in(0) == hidden_merge_mark) {

     // Special marking for internal ex-states.  Process the phis now.

     region->set_req(0, region);  // now it's an ordinary region

     set_jvms(phi_map->jvms());   // ...so now we can use it as a map

     // Note: Setting the jvms also sets the bci and sp.

     set_control(_gvn.transform(region));

     uint tos = jvms()->stkoff() + sp();

     for (uint i = 1; i < tos; i++) {

       Node* x = phi_map->in(i);

       if (x->in(0) == region) {

         assert(x->is_Phi(), "expected a special phi");

         phi_map->set_req(i, _gvn.transform(x));

       }

     }

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

       Node* x = mms.memory();

       if (x->in(0) == region) {

         assert(x->is_Phi(), "nobody else uses a hidden region");

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

       }

     }

     if (ex_oop->in(0) == region) {

       assert(ex_oop->is_Phi(), "expected a special phi");

       ex_oop = _gvn.transform(ex_oop);

     }

   } else {

     set_jvms(phi_map->jvms());

   }

   assert(!is_hidden_merge(phi_map->control()), "hidden ex. states cleared");

   assert(!is_hidden_merge(phi_map->i_o()), "hidden ex. states cleared");

   return ex_oop;

 }

 //---------------------------------java_bc-------------------------------------

 Bytecodes::Code GraphKit::java_bc() const {

   ciMethod* method = this->method();

   int       bci    = this->bci();

   if (method != NULL && bci != InvocationEntryBci)

     return method->java_code_at_bci(bci);

   else

     return Bytecodes::_illegal;

 }

 //------------------------------builtin_throw----------------------------------

 void GraphKit::builtin_throw(Deoptimization::DeoptReason reason, Node* arg) {

   bool must_throw = true;

   if (JvmtiExport::can_post_exceptions()) {

     // Do not try anything fancy if we're notifying the VM on every throw.

     // Cf. case Bytecodes::_athrow in parse2.cpp.

     uncommon_trap(reason, Deoptimization::Action_none,

                   (ciKlass*)NULL, (char*)NULL, must_throw);

     return;

   }

   // If this particular condition has not yet happened at this

   // bytecode, then use the uncommon trap mechanism, and allow for

   // a future recompilation if several traps occur here.

   // If the throw is hot, try to use a more complicated inline mechanism

   // which keeps execution inside the compiled code.

   bool treat_throw_as_hot = false;

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

   if (ProfileTraps) {

     if (too_many_traps(reason)) {

       treat_throw_as_hot = true;

     }

     // (If there is no MDO at all, assume it is early in

     // execution, and that any deopts are part of the

     // startup transient, and don't need to be remembered.)

     // Also, if there is a local exception handler, treat all throws

     // as hot if there has been at least one in this method.

     if (C->trap_count(reason) != 0

         && method()->method_data()->trap_count(reason) != 0

         && has_ex_handler()) {

         treat_throw_as_hot = true;

     }

   }

   // If this throw happens frequently, an uncommon trap might cause

   // a performance pothole.  If there is a local exception handler,

   // and if this particular bytecode appears to be deoptimizing often,

   // let us handle the throw inline, with a preconstructed instance.

   // Note:   If the deopt count has blown up, the uncommon trap

   // runtime is going to flush this nmethod, not matter what.

   if (treat_throw_as_hot

       && (!StackTraceInThrowable || OmitStackTraceInFastThrow)) {

     // If the throw is local, we use a pre-existing instance and

     // punt on the backtrace.  This would lead to a missing backtrace

     // (a repeat of 4292742) if the backtrace object is ever asked

     // for its backtrace.

     // Fixing this remaining case of 4292742 requires some flavor of

     // escape analysis.  Leave that for the future.

     ciInstance* ex_obj = NULL;

     switch (reason) {

     case Deoptimization::Reason_null_check:

       ex_obj = env()->NullPointerException_instance();

       break;

     case Deoptimization::Reason_div0_check:

       ex_obj = env()->ArithmeticException_instance();

       break;

     case Deoptimization::Reason_range_check:

       ex_obj = env()->ArrayIndexOutOfBoundsException_instance();

       break;

     case Deoptimization::Reason_class_check:

       if (java_bc() == Bytecodes::_aastore) {

         ex_obj = env()->ArrayStoreException_instance();

       } else {

         ex_obj = env()->ClassCastException_instance();

       }

       break;

     }

     if (failing()) { stop(); return; }  // exception allocation might fail

     if (ex_obj != NULL) {

       // Cheat with a preallocated exception object.

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

         C->log()->elem("hot_throw preallocated='1' reason='%s'",

                        Deoptimization::trap_reason_name(reason));

       const TypeInstPtr* ex_con  = TypeInstPtr::make(ex_obj);

       Node*              ex_node = _gvn.transform( ConNode::make(C, ex_con) );

       // Clear the detail message of the preallocated exception object.

       // Weblogic sometimes mutates the detail message of exceptions

       // using reflection.

       int offset = java_lang_Throwable::get_detailMessage_offset();

       const TypePtr* adr_typ = ex_con->add_offset(offset);

       Node *adr = basic_plus_adr(ex_node, ex_node, offset);

       Node *store = store_oop_to_object(control(), ex_node, adr, adr_typ, null(), ex_con, T_OBJECT);

       add_exception_state(make_exception_state(ex_node));

       return;

     }

   }

   // %%% Maybe add entry to OptoRuntime which directly throws the exc.?

   // It won't be much cheaper than bailing to the interp., since we'll

   // have to pass up all the debug-info, and the runtime will have to

   // create the stack trace.

   // Usual case:  Bail to interpreter.

   // Reserve the right to recompile if we haven't seen anything yet.

   Deoptimization::DeoptAction action = Deoptimization::Action_maybe_recompile;

   if (treat_throw_as_hot

       && (method()->method_data()->trap_recompiled_at(bci())

           || C->too_many_traps(reason))) {

     // We cannot afford to take more traps here.  Suffer in the interpreter.

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

       C->log()->elem("hot_throw preallocated='0' reason='%s' mcount='%d'",

                      Deoptimization::trap_reason_name(reason),

                      C->trap_count(reason));

     action = Deoptimization::Action_none;

   }

   // "must_throw" prunes the JVM state to include only the stack, if there

   // are no local exception handlers.  This should cut down on register

   // allocation time and code size, by drastically reducing the number

   // of in-edges on the call to the uncommon trap.

   uncommon_trap(reason, action, (ciKlass*)NULL, (char*)NULL, must_throw);

 }

 //----------------------------PreserveJVMState---------------------------------

 PreserveJVMState::PreserveJVMState(GraphKit* kit, bool clone_map) {

   debug_only(kit->verify_map());

   _kit    = kit;

   _map    = kit->map();   // preserve the map

   _sp     = kit->sp();

   kit->set_map(clone_map ? kit->clone_map() : NULL);

 #ifdef ASSERT

   _bci    = kit->bci();

   Parse* parser = kit->is_Parse();

   int block = (parser == NULL || parser->block() == NULL) ? -1 : parser->block()->pre_order();

   _block  = block;

 #endif

 }

 PreserveJVMState::~PreserveJVMState() {

   GraphKit* kit = _kit;

 #ifdef ASSERT

   assert(kit->bci() == _bci, "bci must not shift");

   Parse* parser = kit->is_Parse();

   int block = (parser == NULL || parser->block() == NULL) ? -1 : parser->block()->pre_order();

   assert(block == _block,    "block must not shift");

 #endif

   kit->set_map(_map);

   kit->set_sp(_sp);

 }

 //-----------------------------BuildCutout-------------------------------------

 BuildCutout::BuildCutout(GraphKit* kit, Node* p, float prob, float cnt)

   : PreserveJVMState(kit)

 {

   assert(p->is_Con() || p->is_Bool(), "test must be a bool");

   SafePointNode* outer_map = _map;   // preserved map is caller's

   SafePointNode* inner_map = kit->map();

   IfNode* iff = kit->create_and_map_if(outer_map->control(), p, prob, cnt);

   outer_map->set_control(kit->gvn().transform( new (kit->C, 1) IfTrueNode(iff) ));

   inner_map->set_control(kit->gvn().transform( new (kit->C, 1) IfFalseNode(iff) ));

 }

 BuildCutout::~BuildCutout() {

   GraphKit* kit = _kit;

   assert(kit->stopped(), "cutout code must stop, throw, return, etc.");

 }

 //------------------------------clone_map--------------------------------------

 // Implementation of PreserveJVMState

 //

 // Only clone_map(...) here. If this function is only used in the

 // PreserveJVMState class we may want to get rid of this extra

 // function eventually and do it all there.

 SafePointNode* GraphKit::clone_map() {

   if (map() == NULL)  return NULL;

   // Clone the memory edge first

   Node* mem = MergeMemNode::make(C, map()->memory());

   gvn().set_type_bottom(mem);

   SafePointNode *clonemap = (SafePointNode*)map()->clone();

   JVMState* jvms = this->jvms();

   JVMState* clonejvms = jvms->clone_shallow(C);

   clonemap->set_memory(mem);

   clonemap->set_jvms(clonejvms);

   clonejvms->set_map(clonemap);

   record_for_igvn(clonemap);

   gvn().set_type_bottom(clonemap);

   return clonemap;

 }

 //-----------------------------set_map_clone-----------------------------------

 void GraphKit::set_map_clone(SafePointNode* m) {

   _map = m;

   _map = clone_map();

   _map->set_next_exception(NULL);

   debug_only(verify_map());

 }

 //----------------------------kill_dead_locals---------------------------------

 // Detect any locals which are known to be dead, and force them to top.

 void GraphKit::kill_dead_locals() {

   // Consult the liveness information for the locals.  If any

   // of them are unused, then they can be replaced by top().  This

   // should help register allocation time and cut down on the size

   // of the deoptimization information.

   // This call is made from many of the bytecode handling

   // subroutines called from the Big Switch in do_one_bytecode.

   // Every bytecode which might include a slow path is responsible

   // for killing its dead locals.  The more consistent we

   // are about killing deads, the fewer useless phis will be

   // constructed for them at various merge points.

   // bci can be -1 (InvocationEntryBci).  We return the entry

   // liveness for the method.

   if (method() == NULL || method()->code_size() == 0) {

     // We are building a graph for a call to a native method.

     // All locals are live.

     return;

   }

   ResourceMark rm;

   // Consult the liveness information for the locals.  If any

   // of them are unused, then they can be replaced by top().  This

   // should help register allocation time and cut down on the size

   // of the deoptimization information.

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

   int len = (int)live_locals.size();

   assert(len <= jvms()->loc_size(), "too many live locals");

   for (int local = 0; local < len; local++) {

     if (!live_locals.at(local)) {

       set_local(local, top());

     }

   }

 }

 #ifdef ASSERT

 //-------------------------dead_locals_are_killed------------------------------

 // Return true if all dead locals are set to top in the map.

 // Used to assert "clean" debug info at various points.

 bool GraphKit::dead_locals_are_killed() {

   if (method() == NULL || method()->code_size() == 0) {

     // No locals need to be dead, so all is as it should be.

     return true;

   }

   // Make sure somebody called kill_dead_locals upstream.

   ResourceMark rm;

   for (JVMState* jvms = this->jvms(); jvms != NULL; jvms = jvms->caller()) {

     if (jvms->loc_size() == 0)  continue;  // no locals to consult

     SafePointNode* map = jvms->map();

     ciMethod* method = jvms->method();

     int       bci    = jvms->bci();

     if (jvms == this->jvms()) {

       bci = this->bci();  // it might not yet be synched

     }

     MethodLivenessResult live_locals = method->liveness_at_bci(bci);

     int len = (int)live_locals.size();

     if (!live_locals.is_valid() || len == 0)

       // This method is trivial, or is poisoned by a breakpoint.

       return true;

     assert(len == jvms->loc_size(), "live map consistent with locals map");

     for (int local = 0; local < len; local++) {

       if (!live_locals.at(local) && map->local(jvms, local) != top()) {

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

           tty->print_cr("Zombie local %d: ", local);

           jvms->dump();

         }

         return false;

       }

     }

   }

   return true;

 }

 #endif //ASSERT

 // Helper function for adding JVMState and debug information to node

 void GraphKit::add_safepoint_edges(SafePointNode* call, bool must_throw) {

   // Add the safepoint edges to the call (or other safepoint).

   // Make sure dead locals are set to top.  This

   // should help register allocation time and cut down on the size

   // of the deoptimization information.

   assert(dead_locals_are_killed(), "garbage in debug info before safepoint");

   // Walk the inline list to fill in the correct set of JVMState's

   // Also fill in the associated edges for each JVMState.

   JVMState* youngest_jvms = sync_jvms();

   // Do we need debug info here?  If it is a SafePoint and this method

   // cannot de-opt, then we do NOT need any debug info.

   bool full_info = (C->deopt_happens() || call->Opcode() != Op_SafePoint);

   // If we are guaranteed to throw, we can prune everything but the

   // input to the current bytecode.

   bool can_prune_locals = false;

   uint stack_slots_not_pruned = 0;

   int inputs = 0, depth = 0;

   if (must_throw) {

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

     if (compute_stack_effects(inputs, depth)) {

       can_prune_locals = true;

       stack_slots_not_pruned = inputs;

     }

   }

   if (JvmtiExport::can_examine_or_deopt_anywhere()) {

     // At any safepoint, this method can get breakpointed, which would

     // then require an immediate deoptimization.

     full_info = true;

     can_prune_locals = false;  // do not prune locals

     stack_slots_not_pruned = 0;

   }

   // do not scribble on the input jvms

   JVMState* out_jvms = youngest_jvms->clone_deep(C);

   call->set_jvms(out_jvms); // Start jvms list for call node

   // Presize the call:

   debug_only(uint non_debug_edges = call->req());

   call->add_req_batch(top(), youngest_jvms->debug_depth());

   assert(call->req() == non_debug_edges + youngest_jvms->debug_depth(), "");

   // Set up edges so that the call looks like this:

   //  Call [state:] ctl io mem fptr retadr

   //       [parms:] parm0 ... parmN

   //       [root:]  loc0 ... locN stk0 ... stkSP mon0 obj0 ... monN objN

   //    [...mid:]   loc0 ... locN stk0 ... stkSP mon0 obj0 ... monN objN [...]

   //       [young:] loc0 ... locN stk0 ... stkSP mon0 obj0 ... monN objN

   // Note that caller debug info precedes callee debug info.

   // Fill pointer walks backwards from "young:" to "root:" in the diagram above:

   uint debug_ptr = call->req();

   // Loop over the map input edges associated with jvms, add them

   // to the call node, & reset all offsets to match call node array.

   for (JVMState* in_jvms = youngest_jvms; in_jvms != NULL; ) {

     uint debug_end   = debug_ptr;

     uint debug_start = debug_ptr - in_jvms->debug_size();

     debug_ptr = debug_start;  // back up the ptr

     uint p = debug_start;  // walks forward in [debug_start, debug_end)

     uint j, k, l;

     SafePointNode* in_map = in_jvms->map();

     out_jvms->set_map(call);

     if (can_prune_locals) {

       assert(in_jvms->method() == out_jvms->method(), "sanity");

       // If the current throw can reach an exception handler in this JVMS,

       // then we must keep everything live that can reach that handler.

       // As a quick and dirty approximation, we look for any handlers at all.

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

         can_prune_locals = false;

       }

     }

     // Add the Locals

     k = in_jvms->locoff();

     l = in_jvms->loc_size();

     out_jvms->set_locoff(p);

     if (full_info && !can_prune_locals) {

       for (j = 0; j < l; j++)

         call->set_req(p++, in_map->in(k+j));

     } else {

       p += l;  // already set to top above by add_req_batch

     }

     // Add the Expression Stack

     k = in_jvms->stkoff();

     l = in_jvms->sp();

     out_jvms->set_stkoff(p);

     if (full_info && !can_prune_locals) {

       for (j = 0; j < l; j++)

         call->set_req(p++, in_map->in(k+j));

     } else if (can_prune_locals && stack_slots_not_pruned != 0) {

       // Divide stack into {S0,...,S1}, where S0 is set to top.

       uint s1 = stack_slots_not_pruned;

       stack_slots_not_pruned = 0;  // for next iteration

       if (s1 > l)  s1 = l;

       uint s0 = l - s1;

       p += s0;  // skip the tops preinstalled by add_req_batch

       for (j = s0; j < l; j++)

         call->set_req(p++, in_map->in(k+j));

     } else {

       p += l;  // already set to top above by add_req_batch

     }

     // Add the Monitors

     k = in_jvms->monoff();

     l = in_jvms->mon_size();

     out_jvms->set_monoff(p);

     for (j = 0; j < l; j++)

       call->set_req(p++, in_map->in(k+j));

     // Copy any scalar object fields.

     k = in_jvms->scloff();

     l = in_jvms->scl_size();

     out_jvms->set_scloff(p);

     for (j = 0; j < l; j++)

       call->set_req(p++, in_map->in(k+j));

     // Finish the new jvms.

     out_jvms->set_endoff(p);

     assert(out_jvms->endoff()     == debug_end,             "fill ptr must match");

     assert(out_jvms->depth()      == in_jvms->depth(),      "depth must match");

     assert(out_jvms->loc_size()   == in_jvms->loc_size(),   "size must match");

     assert(out_jvms->mon_size()   == in_jvms->mon_size(),   "size must match");

     assert(out_jvms->scl_size()   == in_jvms->scl_size(),   "size must match");

     assert(out_jvms->debug_size() == in_jvms->debug_size(), "size must match");

     // Update the two tail pointers in parallel.

     out_jvms = out_jvms->caller();

     in_jvms  = in_jvms->caller();

   }

   assert(debug_ptr == non_debug_edges, "debug info must fit exactly");

   // Test the correctness of JVMState::debug_xxx accessors:

   assert(call->jvms()->debug_start() == non_debug_edges, "");

   assert(call->jvms()->debug_end()   == call->req(), "");

   assert(call->jvms()->debug_depth() == call->req() - non_debug_edges, "");

 }

 bool GraphKit::compute_stack_effects(int& inputs, int& depth) {

   Bytecodes::Code code = java_bc();

   if (code == Bytecodes::_wide) {

     code = method()->java_code_at_bci(bci() + 1);

   }

   BasicType rtype = T_ILLEGAL;

   int       rsize = 0;

   if (code != Bytecodes::_illegal) {

     depth = Bytecodes::depth(code); // checkcast=0, athrow=-1

     rtype = Bytecodes::result_type(code); // checkcast=P, athrow=V

     if (rtype < T_CONFLICT)

       rsize = type2size[rtype];

   }

   switch (code) {

   case Bytecodes::_illegal:

     return false;

   case Bytecodes::_ldc:

   case Bytecodes::_ldc_w:

   case Bytecodes::_ldc2_w:

     inputs = 0;

     break;

   case Bytecodes::_dup:         inputs = 1;  break;

   case Bytecodes::_dup_x1:      inputs = 2;  break;

   case Bytecodes::_dup_x2:      inputs = 3;  break;

   case Bytecodes::_dup2:        inputs = 2;  break;

   case Bytecodes::_dup2_x1:     inputs = 3;  break;

   case Bytecodes::_dup2_x2:     inputs = 4;  break;

   case Bytecodes::_swap:        inputs = 2;  break;

   case Bytecodes::_arraylength: inputs = 1;  break;

   case Bytecodes::_getstatic:

   case Bytecodes::_putstatic:

   case Bytecodes::_getfield:

   case Bytecodes::_putfield:

     {

       bool is_get = (depth >= 0), is_static = (depth & 1);

       bool ignore;

       ciBytecodeStream iter(method());

       iter.reset_to_bci(bci());

       iter.next();

       ciField* field = iter.get_field(ignore);

       int      size  = field->type()->size();

       inputs  = (is_static ? 0 : 1);

       if (is_get) {

         depth = size - inputs;

       } else {

         inputs += size;        // putxxx pops the value from the stack

         depth = - inputs;

       }

     }

     break;

   case Bytecodes::_invokevirtual:

   case Bytecodes::_invokespecial:

   case Bytecodes::_invokestatic:

   case Bytecodes::_invokeinterface:

     {

       bool is_static = (depth == 0);

       bool ignore;

       ciBytecodeStream iter(method());

       iter.reset_to_bci(bci());

       iter.next();

       ciMethod* method = iter.get_method(ignore);

       inputs = method->arg_size_no_receiver();

       if (!is_static)  inputs += 1;

       int size = method->return_type()->size();

       depth = size - inputs;

     }

     break;

   case Bytecodes::_multianewarray:

     {

       ciBytecodeStream iter(method());

       iter.reset_to_bci(bci());

       iter.next();

       inputs = iter.get_dimensions();

       assert(rsize == 1, "");

       depth = rsize - inputs;

     }

     break;

   case Bytecodes::_ireturn:

   case Bytecodes::_lreturn:

   case Bytecodes::_freturn:

   case Bytecodes::_dreturn:

   case Bytecodes::_areturn:

     assert(rsize = -depth, "");

     inputs = rsize;

     break;

   case Bytecodes::_jsr:

   case Bytecodes::_jsr_w:

     inputs = 0;

     depth  = 1;                  // S.B. depth=1, not zero

     break;

   default:

     // bytecode produces a typed result

     inputs = rsize - depth;

     assert(inputs >= 0, "");

     break;

   }

 #ifdef ASSERT

   // spot check

   int outputs = depth + inputs;

   assert(outputs >= 0, "sanity");

   switch (code) {

   case Bytecodes::_checkcast: assert(inputs == 1 && outputs == 1, ""); break;

   case Bytecodes::_athrow:    assert(inputs == 1 && outputs == 0, ""); break;

   case Bytecodes::_aload_0:   assert(inputs == 0 && outputs == 1, ""); break;

   case Bytecodes::_return:    assert(inputs == 0 && outputs == 0, ""); break;

   case Bytecodes::_drem:      assert(inputs == 4 && outputs == 2, ""); break;

   }

 #endif //ASSERT

   return true;

 }

 //------------------------------basic_plus_adr---------------------------------

 Node* GraphKit::basic_plus_adr(Node* base, Node* ptr, Node* offset) {

   // short-circuit a common case

   if (offset == intcon(0))  return ptr;

   return _gvn.transform( new (C, 4) AddPNode(base, ptr, offset) );

 }

 Node* GraphKit::ConvI2L(Node* offset) {

   // short-circuit a common case

   jint offset_con = find_int_con(offset, Type::OffsetBot);

   if (offset_con != Type::OffsetBot) {

     return longcon((long) offset_con);

   }

   return _gvn.transform( new (C, 2) ConvI2LNode(offset));

 }

 Node* GraphKit::ConvL2I(Node* offset) {

   // short-circuit a common case

   jlong offset_con = find_long_con(offset, (jlong)Type::OffsetBot);

   if (offset_con != (jlong)Type::OffsetBot) {

     return intcon((int) offset_con);

   }

   return _gvn.transform( new (C, 2) ConvL2INode(offset));

 }

 //-------------------------load_object_klass-----------------------------------

 Node* GraphKit::load_object_klass(Node* obj) {

   // Special-case a fresh allocation to avoid building nodes:

   Node* akls = AllocateNode::Ideal_klass(obj, &_gvn);

   if (akls != NULL)  return akls;

   Node* k_adr = basic_plus_adr(obj, oopDesc::klass_offset_in_bytes());

   return _gvn.transform( LoadKlassNode::make(_gvn, immutable_memory(), k_adr, TypeInstPtr::KLASS) );

 }

 //-------------------------load_array_length-----------------------------------

 Node* GraphKit::load_array_length(Node* array) {

   // Special-case a fresh allocation to avoid building nodes:

   Node* alen = AllocateArrayNode::Ideal_length(array, &_gvn);

   if (alen != NULL)  return alen;

   Node *r_adr = basic_plus_adr(array, arrayOopDesc::length_offset_in_bytes());

   return _gvn.transform( new (C, 3) LoadRangeNode(0, immutable_memory(), r_adr, TypeInt::POS));

 }

 //------------------------------do_null_check----------------------------------

 // Helper function to do a NULL pointer check.  Returned value is

 // the incoming address with NULL casted away.  You are allowed to use the

 // not-null value only if you are control dependent on the test.

 extern int explicit_null_checks_inserted,

            explicit_null_checks_elided;

 Node* GraphKit::null_check_common(Node* value, BasicType type,

                                   // optional arguments for variations:

                                   bool assert_null,

                                   Node* *null_control) {

   assert(!assert_null || null_control == NULL, "not both at once");

   if (stopped())  return top();

   if (!GenerateCompilerNullChecks && !assert_null && null_control == NULL) {

     // For some performance testing, we may wish to suppress null checking.

     value = cast_not_null(value);   // Make it appear to be non-null (4962416).

     return value;

   }

   explicit_null_checks_inserted++;

   // Construct NULL check

   Node *chk = NULL;

   switch(type) {

     case T_LONG   : chk = new (C, 3) CmpLNode(value, _gvn.zerocon(T_LONG)); break;

     case T_INT    : chk = new (C, 3) CmpINode( value, _gvn.intcon(0)); break;

     case T_ARRAY  : // fall through

       type = T_OBJECT;  // simplify further tests

     case T_OBJECT : {

       const Type *t = _gvn.type( value );

       const TypeInstPtr* tp = t->isa_instptr();

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

           // Only for do_null_check, not any of its siblings:

           && !assert_null && null_control == NULL) {

         // Usually, any field access or invocation on an unloaded oop type

         // will simply fail to link, since the statically linked class is

         // likely also to be unloaded.  However, in -Xcomp mode, sometimes

         // the static class is loaded but the sharper oop type is not.

         // Rather than checking for this obscure case in lots of places,

         // we simply observe that a null check on an unloaded class

         // will always be followed by a nonsense operation, so we

         // can just issue the uncommon trap here.

         // Our access to the unloaded class will only be correct

         // after it has been loaded and initialized, which requires

         // a trip through the interpreter.

 #ifndef PRODUCT

         if (WizardMode) { tty->print("Null check of unloaded "); tp->klass()->print(); tty->cr(); }

 #endif

         uncommon_trap(Deoptimization::Reason_unloaded,

                       Deoptimization::Action_reinterpret,

                       tp->klass(), "!loaded");

         return top();

       }

       if (assert_null) {

         // See if the type is contained in NULL_PTR.

         // If so, then the value is already null.

         if (t->higher_equal(TypePtr::NULL_PTR)) {

           explicit_null_checks_elided++;

           return value;           // Elided null assert quickly!

         }

       } else {

         // See if mixing in the NULL pointer changes type.

         // If so, then the NULL pointer was not allowed in the original

         // type.  In other words, "value" was not-null.

         if (t->meet(TypePtr::NULL_PTR) != t) {

           // same as: if (!TypePtr::NULL_PTR->higher_equal(t)) ...

           explicit_null_checks_elided++;

           return value;           // Elided null check quickly!

         }

       }

       chk = new (C, 3) CmpPNode( value, null() );

       break;

     }

     default      : ShouldNotReachHere();

   }

   assert(chk != NULL, "sanity check");

   chk = _gvn.transform(chk);

   BoolTest::mask btest = assert_null ? BoolTest::eq : BoolTest::ne;

   BoolNode *btst = new (C, 2) BoolNode( chk, btest);

   Node   *tst = _gvn.transform( btst );

   //-----------

   // if peephole optimizations occured, a prior test existed.

   // If a prior test existed, maybe it dominates as we can avoid this test.

   if (tst != btst && type == T_OBJECT) {

     // At this point we want to scan up the CFG to see if we can

     // find an identical test (and so avoid this test altogether).

     Node *cfg = control();

     int depth = 0;

     while( depth < 16 ) {       // Limit search depth for speed

       if( cfg->Opcode() == Op_IfTrue &&

           cfg->in(0)->in(1) == tst ) {

         // Found prior test.  Use "cast_not_null" to construct an identical

         // CastPP (and hence hash to) as already exists for the prior test.

         // Return that casted value.

         if (assert_null) {

           replace_in_map(value, null());

           return null();  // do not issue the redundant test

         }

         Node *oldcontrol = control();

         set_control(cfg);

         Node *res = cast_not_null(value);

         set_control(oldcontrol);

         explicit_null_checks_elided++;

         return res;

       }

       cfg = IfNode::up_one_dom(cfg, /*linear_only=*/ true);

       if (cfg == NULL)  break;  // Quit at region nodes

       depth++;

     }

   }

   //-----------

   // Branch to failure if null

   float ok_prob = PROB_MAX;  // a priori estimate:  nulls never happen

   Deoptimization::DeoptReason reason;

   if (assert_null)

     reason = Deoptimization::Reason_null_assert;

   else if (type == T_OBJECT)

     reason = Deoptimization::Reason_null_check;

   else

     reason = Deoptimization::Reason_div0_check;

   // To cause an implicit null check, we set the not-null probability

   // to the maximum (PROB_MAX).  For an explicit check the probablity

   // is set to a smaller value.

   if (null_control != NULL || too_many_traps(reason)) {

     // probability is less likely

     ok_prob =  PROB_LIKELY_MAG(3);

   } else if (!assert_null &&

              (ImplicitNullCheckThreshold > 0) &&

              method() != NULL &&

              (method()->method_data()->trap_count(reason)

               >= (uint)ImplicitNullCheckThreshold)) {

     ok_prob =  PROB_LIKELY_MAG(3);

   }

   if (null_control != NULL) {

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

     Node* null_true = _gvn.transform( new (C, 1) IfFalseNode(iff));

     set_control(      _gvn.transform( new (C, 1) IfTrueNode(iff)));

     if (null_true == top())

       explicit_null_checks_elided++;

     (*null_control) = null_true;

   } else {

     BuildCutout unless(this, tst, ok_prob);

     // Check for optimizer eliding test at parse time

     if (stopped()) {

       // Failure not possible; do not bother making uncommon trap.

       explicit_null_checks_elided++;

     } else if (assert_null) {

       uncommon_trap(reason,

                     Deoptimization::Action_make_not_entrant,

                     NULL, "assert_null");

     } else {

       replace_in_map(value, zerocon(type));

       builtin_throw(reason);

     }

   }

   // Must throw exception, fall-thru not possible?

   if (stopped()) {

     return top();               // No result

   }

   if (assert_null) {

     // Cast obj to null on this path.

     replace_in_map(value, zerocon(type));

     return zerocon(type);

   }

   // Cast obj to not-null on this path, if there is no null_control.

   // (If there is a null_control, a non-null value may come back to haunt us.)

   if (type == T_OBJECT) {

     Node* cast = cast_not_null(value, false);

     if (null_control == NULL || (*null_control) == top())

       replace_in_map(value, cast);

     value = cast;

   }

   return value;

 }

 //------------------------------cast_not_null----------------------------------

 // Cast obj to not-null on this path

 Node* GraphKit::cast_not_null(Node* obj, bool do_replace_in_map) {

   const Type *t = _gvn.type(obj);

   const Type *t_not_null = t->join(TypePtr::NOTNULL);

   // Object is already not-null?

   if( t == t_not_null ) return obj;

   Node *cast = new (C, 2) CastPPNode(obj,t_not_null);

   cast->init_req(0, control());

   cast = _gvn.transform( cast );

   // Scan for instances of 'obj' in the current JVM mapping.

   // These instances are known to be not-null after the test.

   if (do_replace_in_map)

     replace_in_map(obj, cast);

   return cast;                  // Return casted value

 }

 //--------------------------replace_in_map-------------------------------------

 void GraphKit::replace_in_map(Node* old, Node* neww) {

   this->map()->replace_edge(old, neww);

   // Note: This operation potentially replaces any edge

   // on the map.  This includes locals, stack, and monitors

   // of the current (innermost) JVM state.

   // We can consider replacing in caller maps.

   // The idea would be that an inlined function's null checks

   // can be shared with the entire inlining tree.

   // The expense of doing this is that the PreserveJVMState class

   // would have to preserve caller states too, with a deep copy.

 }

 //=============================================================================

 //--------------------------------memory---------------------------------------

 Node* GraphKit::memory(uint alias_idx) {

   MergeMemNode* mem = merged_memory();

   Node* p = mem->memory_at(alias_idx);

   _gvn.set_type(p, Type::MEMORY);  // must be mapped

   return p;

 }

 //-----------------------------reset_memory------------------------------------

 Node* GraphKit::reset_memory() {

   Node* mem = map()->memory();

   // do not use this node for any more parsing!

   debug_only( map()->set_memory((Node*)NULL) );

   return _gvn.transform( mem );

 }

 //------------------------------set_all_memory---------------------------------

 void GraphKit::set_all_memory(Node* newmem) {

   Node* mergemem = MergeMemNode::make(C, newmem);

   gvn().set_type_bottom(mergemem);

   map()->set_memory(mergemem);

 }

 //------------------------------set_all_memory_call----------------------------

 void GraphKit::set_all_memory_call(Node* call) {

   Node* newmem = _gvn.transform( new (C, 1) ProjNode(call, TypeFunc::Memory) );

   set_all_memory(newmem);

 }

 //=============================================================================

 //

 // parser factory methods for MemNodes

 //

 // These are layered on top of the factory methods in LoadNode and StoreNode,

 // and integrate with the parser's memory state and _gvn engine.

 //

 // factory methods in "int adr_idx"

 Node* GraphKit::make_load(Node* ctl, Node* adr, const Type* t, BasicType bt,

                           int adr_idx,

                           bool require_atomic_access) {

   assert(adr_idx != Compile::AliasIdxTop, "use other make_load factory" );

   const TypePtr* adr_type = NULL; // debug-mode-only argument

   debug_only(adr_type = C->get_adr_type(adr_idx));

   Node* mem = memory(adr_idx);

   Node* ld;

   if (require_atomic_access && bt == T_LONG) {

     ld = LoadLNode::make_atomic(C, ctl, mem, adr, adr_type, t);

   } else {

     ld = LoadNode::make(_gvn, ctl, mem, adr, adr_type, t, bt);

   }

   return _gvn.transform(ld);

 }

 Node* GraphKit::store_to_memory(Node* ctl, Node* adr, Node *val, BasicType bt,

                                 int adr_idx,

                                 bool require_atomic_access) {

   assert(adr_idx != Compile::AliasIdxTop, "use other store_to_memory factory" );

   const TypePtr* adr_type = NULL;

   debug_only(adr_type = C->get_adr_type(adr_idx));

   Node *mem = memory(adr_idx);

   Node* st;

   if (require_atomic_access && bt == T_LONG) {

     st = StoreLNode::make_atomic(C, ctl, mem, adr, adr_type, val);

   } else {

     st = StoreNode::make(_gvn, ctl, mem, adr, adr_type, val, bt);

   }

   st = _gvn.transform(st);

   set_memory(st, adr_idx);

   // Back-to-back stores can only remove intermediate store with DU info

   // so push on worklist for optimizer.

   if (mem->req() > MemNode::Address && adr == mem->in(MemNode::Address))

     record_for_igvn(st);

   return st;

 }

 void GraphKit::pre_barrier(Node* ctl,

                            Node* obj,

                            Node* adr,

                            uint adr_idx,

                            Node *val,

                            const Type* val_type,

                            BasicType bt) {

   BarrierSet* bs = Universe::heap()->barrier_set();

   set_control(ctl);

   switch (bs->kind()) {

     case BarrierSet::CardTableModRef:

     case BarrierSet::CardTableExtension:

     case BarrierSet::ModRef:

       break;

     case BarrierSet::Other:

     default      :

       ShouldNotReachHere();

   }

 }

 void GraphKit::post_barrier(Node* ctl,

                             Node* store,

                             Node* obj,

                             Node* adr,

                             uint adr_idx,

                             Node *val,

                             BasicType bt,

                             bool use_precise) {

   BarrierSet* bs = Universe::heap()->barrier_set();

   set_control(ctl);

   switch (bs->kind()) {

     case BarrierSet::CardTableModRef:

     case BarrierSet::CardTableExtension:

       write_barrier_post(store, obj, adr, val, use_precise);

       break;

     case BarrierSet::ModRef:

       break;

     case BarrierSet::Other:

     default      :

       ShouldNotReachHere();

   }

 }

 Node* GraphKit::store_oop_to_object(Node* ctl,

                                     Node* obj,

                                     Node* adr,

                                     const TypePtr* adr_type,

                                     Node *val,

                                     const Type* val_type,

                                     BasicType bt) {

   uint adr_idx = C->get_alias_index(adr_type);

   Node* store;

   pre_barrier(ctl, obj, adr, adr_idx, val, val_type, bt);

   store = store_to_memory(control(), adr, val, bt, adr_idx);

   post_barrier(control(), store, obj, adr, adr_idx, val, bt, false);

   return store;

 }

 Node* GraphKit::store_oop_to_array(Node* ctl,

                                    Node* obj,

                                    Node* adr,

                                    const TypePtr* adr_type,

                                    Node *val,

                                    const Type* val_type,

                                    BasicType bt) {

   uint adr_idx = C->get_alias_index(adr_type);

   Node* store;

   pre_barrier(ctl, obj, adr, adr_idx, val, val_type, bt);

   store = store_to_memory(control(), adr, val, bt, adr_idx);

   post_barrier(control(), store, obj, adr, adr_idx, val, bt, true);

   return store;

 }

 Node* GraphKit::store_oop_to_unknown(Node* ctl,

                                      Node* obj,

                                      Node* adr,

                                      const TypePtr* adr_type,

                                      Node *val,

                                      const Type* val_type,

                                      BasicType bt) {

   uint adr_idx = C->get_alias_index(adr_type);

   Node* store;

   pre_barrier(ctl, obj, adr, adr_idx, val, val_type, bt);

   store = store_to_memory(control(), adr, val, bt, adr_idx);

   post_barrier(control(), store, obj, adr, adr_idx, val, bt, true);

   return store;

 }

 //-------------------------array_element_address-------------------------

 Node* GraphKit::array_element_address(Node* ary, Node* idx, BasicType elembt,

                                       const TypeInt* sizetype) {

   uint shift  = exact_log2(type2aelembytes(elembt));

   uint header = arrayOopDesc::base_offset_in_bytes(elembt);

   // short-circuit a common case (saves lots of confusing waste motion)

   jint idx_con = find_int_con(idx, -1);

   if (idx_con >= 0) {

     intptr_t offset = header + ((intptr_t)idx_con << shift);

     return basic_plus_adr(ary, offset);

   }

   // must be correct type for alignment purposes

   Node* base  = basic_plus_adr(ary, header);

 #ifdef _LP64

   // The scaled index operand to AddP must be a clean 64-bit value.

   // Java allows a 32-bit int to be incremented to a negative

   // value, which appears in a 64-bit register as a large

   // positive number.  Using that large positive number as an

   // operand in pointer arithmetic has bad consequences.

   // On the other hand, 32-bit overflow is rare, and the possibility

   // can often be excluded, if we annotate the ConvI2L node with

   // a type assertion that its value is known to be a small positive

   // number.  (The prior range check has ensured this.)

   // This assertion is used by ConvI2LNode::Ideal.

   int index_max = max_jint - 1;  // array size is max_jint, index is one less

   if (sizetype != NULL)  index_max = sizetype->_hi - 1;

   const TypeLong* lidxtype = TypeLong::make(CONST64(0), index_max, Type::WidenMax);

   idx = _gvn.transform( new (C, 2) ConvI2LNode(idx, lidxtype) );

 #endif

   Node* scale = _gvn.transform( new (C, 3) LShiftXNode(idx, intcon(shift)) );

   return basic_plus_adr(ary, base, scale);

 }

 //-------------------------load_array_element-------------------------

 Node* GraphKit::load_array_element(Node* ctl, Node* ary, Node* idx, const TypeAryPtr* arytype) {

   const Type* elemtype = arytype->elem();

   BasicType elembt = elemtype->array_element_basic_type();

   Node* adr = array_element_address(ary, idx, elembt, arytype->size());

   Node* ld = make_load(ctl, adr, elemtype, elembt, arytype);

   return ld;

 }

 //-------------------------set_arguments_for_java_call-------------------------

 // Arguments (pre-popped from the stack) are taken from the JVMS.

 void GraphKit::set_arguments_for_java_call(CallJavaNode* call) {

   // Add the call arguments:

   uint nargs = call->method()->arg_size();

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

     Node* arg = argument(i);

     call->init_req(i + TypeFunc::Parms, arg);

   }

 }

 //---------------------------set_edges_for_java_call---------------------------

 // Connect a newly created call into the current JVMS.

 // A return value node (if any) is returned from set_edges_for_java_call.

 void GraphKit::set_edges_for_java_call(CallJavaNode* call, bool must_throw) {

   // Add the predefined inputs:

   call->init_req( TypeFunc::Control, control() );

   call->init_req( TypeFunc::I_O    , i_o() );

   call->init_req( TypeFunc::Memory , reset_memory() );

   call->init_req( TypeFunc::FramePtr, frameptr() );

   call->init_req( TypeFunc::ReturnAdr, top() );

   add_safepoint_edges(call, must_throw);

   Node* xcall = _gvn.transform(call);

   if (xcall == top()) {

     set_control(top());

     return;

   }

   assert(xcall == call, "call identity is stable");

   // Re-use the current map to produce the result.

   set_control(_gvn.transform(new (C, 1) ProjNode(call, TypeFunc::Control)));

   set_i_o(    _gvn.transform(new (C, 1) ProjNode(call, TypeFunc::I_O    )));

   set_all_memory_call(xcall);

   //return xcall;   // no need, caller already has it

 }

 Node* GraphKit::set_results_for_java_call(CallJavaNode* call) {

   if (stopped())  return top();  // maybe the call folded up?

   // Capture the return value, if any.

   Node* ret;

   if (call->method() == NULL ||

       call->method()->return_type()->basic_type() == T_VOID)

         ret = top();

   else  ret = _gvn.transform(new (C, 1) ProjNode(call, TypeFunc::Parms));

   // Note:  Since any out-of-line call can produce an exception,

   // we always insert an I_O projection from the call into the result.

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

   return ret;

 }

 //--------------------set_predefined_input_for_runtime_call--------------------

 // Reading and setting the memory state is way conservative here.

 // The real problem is that I am not doing real Type analysis on memory,

 // so I cannot distinguish card mark stores from other stores.  Across a GC

 // point the Store Barrier and the card mark memory has to agree.  I cannot

 // have a card mark store and its barrier split across the GC point from

 // either above or below.  Here I get that to happen by reading ALL of memory.

 // A better answer would be to separate out card marks from other memory.

 // For now, return the input memory state, so that it can be reused

 // after the call, if this call has restricted memory effects.

 Node* GraphKit::set_predefined_input_for_runtime_call(SafePointNode* call) {

   // Set fixed predefined input arguments

   Node* memory = reset_memory();

   call->init_req( TypeFunc::Control,   control()  );

   call->init_req( TypeFunc::I_O,       top()      ); // does no i/o

   call->init_req( TypeFunc::Memory,    memory     ); // may gc ptrs

   call->init_req( TypeFunc::FramePtr,  frameptr() );

   call->init_req( TypeFunc::ReturnAdr, top()      );

   return memory;

 }

 //-------------------set_predefined_output_for_runtime_call--------------------

 // Set control and memory (not i_o) from the call.

 // If keep_mem is not NULL, use it for the output state,

 // except for the RawPtr output of the call, if hook_mem is TypeRawPtr::BOTTOM.

 // If hook_mem is NULL, this call produces no memory effects at all.

 // If hook_mem is a Java-visible memory slice (such as arraycopy operands),

 // then only that memory slice is taken from the call.

 // In the last case, we must put an appropriate memory barrier before

 // the call, so as to create the correct anti-dependencies on loads

 // preceding the call.

 void GraphKit::set_predefined_output_for_runtime_call(Node* call,

                                                       Node* keep_mem,

                                                       const TypePtr* hook_mem) {

   // no i/o

   set_control(_gvn.transform( new (C, 1) ProjNode(call,TypeFunc::Control) ));

   if (keep_mem) {

     // First clone the existing memory state

     set_all_memory(keep_mem);

     if (hook_mem != NULL) {

       // Make memory for the call

       Node* mem = _gvn.transform( new (C, 1) ProjNode(call, TypeFunc::Memory) );

       // Set the RawPtr memory state only.  This covers all the heap top/GC stuff

       // We also use hook_mem to extract specific effects from arraycopy stubs.

       set_memory(mem, hook_mem);

     }

     // ...else the call has NO memory effects.

     // Make sure the call advertises its memory effects precisely.

     // This lets us build accurate anti-dependences in gcm.cpp.

     assert(C->alias_type(call->adr_type()) == C->alias_type(hook_mem),

            "call node must be constructed correctly");

   } else {

     assert(hook_mem == NULL, "");

     // This is not a "slow path" call; all memory comes from the call.

     set_all_memory_call(call);

   }

 }

 //------------------------------increment_counter------------------------------

 // for statistics: increment a VM counter by 1

 void GraphKit::increment_counter(address counter_addr) {

   Node* adr1 = makecon(TypeRawPtr::make(counter_addr));

   increment_counter(adr1);

 }

 void GraphKit::increment_counter(Node* counter_addr) {

   int adr_type = Compile::AliasIdxRaw;

   Node* cnt  = make_load(NULL, counter_addr, TypeInt::INT, T_INT, adr_type);

   Node* incr = _gvn.transform(new (C, 3) AddINode(cnt, _gvn.intcon(1)));

   store_to_memory( NULL, counter_addr, incr, T_INT, adr_type );

 }

 //------------------------------uncommon_trap----------------------------------

 // Bail out to the interpreter in mid-method.  Implemented by calling the

 // uncommon_trap blob.  This helper function inserts a runtime call with the

 // right debug info.

 void GraphKit::uncommon_trap(int trap_request,

                              ciKlass* klass, const char* comment,

                              bool must_throw,

                              bool keep_exact_action) {

   if (failing())  stop();

   if (stopped())  return; // trap reachable?

   // Note:  If ProfileTraps is true, and if a deopt. actually

   // occurs here, the runtime will make sure an MDO exists.  There is

   // no need to call method()->build_method_data() at this point.

 #ifdef ASSERT

   if (!must_throw) {

     // Make sure the stack has at least enough depth to execute

     // the current bytecode.

     int inputs, ignore;

     if (compute_stack_effects(inputs, ignore)) {

       assert(sp() >= inputs, "must have enough JVMS stack to execute");

       // It is a frequent error in library_call.cpp to issue an

       // uncommon trap with the _sp value already popped.

     }

   }

 #endif

   Deoptimization::DeoptReason reason = Deoptimization::trap_request_reason(trap_request);

   Deoptimization::DeoptAction action = Deoptimization::trap_request_action(trap_request);

   switch (action) {

   case Deoptimization::Action_maybe_recompile:

   case Deoptimization::Action_reinterpret:

     // Temporary fix for 6529811 to allow virtual calls to be sure they

     // get the chance to go from mono->bi->mega

     if (!keep_exact_action &&

         Deoptimization::trap_request_index(trap_request) < 0 &&

         too_many_recompiles(reason)) {

       // This BCI is causing too many recompilations.

       action = Deoptimization::Action_none;

       trap_request = Deoptimization::make_trap_request(reason, action);

     } else {

       C->set_trap_can_recompile(true);

     }

     break;

   case Deoptimization::Action_make_not_entrant:

     C->set_trap_can_recompile(true);

     break;

 #ifdef ASSERT

   case Deoptimization::Action_none:

   case Deoptimization::Action_make_not_compilable:

     break;

   default:

     assert(false, "bad action");

 #endif

   }

   if (TraceOptoParse) {

     char buf[100];

     tty->print_cr("Uncommon trap %s at bci:%d",

                   Deoptimization::format_trap_request(buf, sizeof(buf),

                                                       trap_request), bci());

   }

   CompileLog* log = C->log();

   if (log != NULL) {

     int kid = (klass == NULL)? -1: log->identify(klass);

     log->begin_elem("uncommon_trap bci='%d'", bci());

     char buf[100];

     log->print(" %s", Deoptimization::format_trap_request(buf, sizeof(buf),

                                                           trap_request));

     if (kid >= 0)         log->print(" klass='%d'", kid);

     if (comment != NULL)  log->print(" comment='%s'", comment);

     log->end_elem();

   }

   // Make sure any guarding test views this path as very unlikely

   Node *i0 = control()->in(0);

   if (i0 != NULL && i0->is_If()) {        // Found a guarding if test?

     IfNode *iff = i0->as_If();

     float f = iff->_prob;   // Get prob

     if (control()->Opcode() == Op_IfTrue) {

       if (f > PROB_UNLIKELY_MAG(4))

         iff->_prob = PROB_MIN;

     } else {

       if (f < PROB_LIKELY_MAG(4))

         iff->_prob = PROB_MAX;

     }

   }

   // Clear out dead values from the debug info.

   kill_dead_locals();

   // Now insert the uncommon trap subroutine call

   address call_addr = SharedRuntime::uncommon_trap_blob()->instructions_begin();

   const TypePtr* no_memory_effects = NULL;

   // Pass the index of the class to be loaded

   Node* call = make_runtime_call(RC_NO_LEAF | RC_UNCOMMON |

                                  (must_throw ? RC_MUST_THROW : 0),

                                  OptoRuntime::uncommon_trap_Type(),

                                  call_addr, "uncommon_trap", no_memory_effects,

                                  intcon(trap_request));

   assert(call->as_CallStaticJava()->uncommon_trap_request() == trap_request,

          "must extract request correctly from the graph");

   assert(trap_request != 0, "zero value reserved by uncommon_trap_request");

   call->set_req(TypeFunc::ReturnAdr, returnadr());

   // The debug info is the only real input to this call.

   // Halt-and-catch fire here.  The above call should never return!

   HaltNode* halt = new(C, TypeFunc::Parms) HaltNode(control(), frameptr());

   _gvn.set_type_bottom(halt);

   root()->add_req(halt);

   stop_and_kill_map();

 }

 //--------------------------just_allocated_object------------------------------

 // Report the object that was just allocated.

 // It must be the case that there are no intervening safepoints.

 // We use this to determine if an object is so "fresh" that

 // it does not require card marks.

 Node* GraphKit::just_allocated_object(Node* current_control) {

   if (C->recent_alloc_ctl() == current_control)

     return C->recent_alloc_obj();

   return NULL;

 }

 //------------------------------store_barrier----------------------------------

 // Insert a write-barrier store.  This is to let generational GC work; we have

 // to flag all oop-stores before the next GC point.

 void GraphKit::write_barrier_post(Node* oop_store, Node* obj, Node* adr,

                                   Node* val, bool use_precise) {

   // No store check needed if we're storing a NULL or an old object

   // (latter case is probably a string constant). The concurrent

   // mark sweep garbage collector, however, needs to have all nonNull

   // oop updates flagged via card-marks.

   if (val != NULL && val->is_Con()) {

     // must be either an oop or NULL

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

     if (t == TypePtr::NULL_PTR || t == Type::TOP)

       // stores of null never (?) need barriers

       return;

     ciObject* con = t->is_oopptr()->const_oop();

     if (con != NULL

         && con->is_perm()

         && Universe::heap()->can_elide_permanent_oop_store_barriers())

       // no store barrier needed, because no old-to-new ref created

       return;

   }

   if (use_ReduceInitialCardMarks()

       && obj == just_allocated_object(control())) {

     // We can skip marks on a freshly-allocated object.

     // Keep this code in sync with do_eager_card_mark in runtime.cpp.

     // That routine eagerly marks the occasional object which is produced

     // by the slow path, so that we don't have to do it here.

     return;

   }

   if (!use_precise) {

     // All card marks for a (non-array) instance are in one place:

     adr = obj;

   }

   // (Else it's an array (or unknown), and we want more precise card marks.)

   assert(adr != NULL, "");

   // Get the alias_index for raw card-mark memory

   int adr_type = Compile::AliasIdxRaw;

   // Convert the pointer to an int prior to doing math on it

   Node* cast = _gvn.transform(new (C, 2) CastP2XNode(control(), adr));

   // Divide by card size

   assert(Universe::heap()->barrier_set()->kind() == BarrierSet::CardTableModRef,

          "Only one we handle so far.");

   CardTableModRefBS* ct =

     (CardTableModRefBS*)(Universe::heap()->barrier_set());

   Node *b = _gvn.transform(new (C, 3) URShiftXNode( cast, _gvn.intcon(CardTableModRefBS::card_shift) ));

   // We store into a byte array, so do not bother to left-shift by zero

   // Get base of card map

   assert(sizeof(*ct->byte_map_base) == sizeof(jbyte),

          "adjust this code");

   Node *c = makecon(TypeRawPtr::make((address)ct->byte_map_base));

   // Combine

   Node *sb_ctl = control();

   Node *sb_adr = _gvn.transform(new (C, 4) AddPNode( top()/*no base ptr*/, c, b ));

   Node *sb_val = _gvn.intcon(0);

   // Smash zero into card

   if( !UseConcMarkSweepGC ) {

     BasicType bt = T_BYTE;

     store_to_memory(sb_ctl, sb_adr, sb_val, bt, adr_type);

   } else {

     // Specialized path for CM store barrier

     cms_card_mark( sb_ctl, sb_adr, sb_val, oop_store);

   }

 }

 // Specialized path for CMS store barrier

 void GraphKit::cms_card_mark(Node* ctl, Node* adr, Node* val, Node *oop_store) {

   BasicType bt = T_BYTE;

   int adr_idx = Compile::AliasIdxRaw;

   Node* mem = memory(adr_idx);

   // The type input is NULL in PRODUCT builds

   const TypePtr* type = NULL;

   debug_only(type = C->get_adr_type(adr_idx));

   // Add required edge to oop_store, optimizer does not support precedence edges.

   // Convert required edge to precedence edge before allocation.

   Node *store = _gvn.transform( new (C, 5) StoreCMNode(ctl, mem, adr, type, val, oop_store) );

   set_memory(store, adr_idx);

   // For CMS, back-to-back card-marks can only remove the first one

   // and this requires DU info.  Push on worklist for optimizer.

   if (mem->req() > MemNode::Address && adr == mem->in(MemNode::Address))

     record_for_igvn(store);

 }

 void GraphKit::round_double_arguments(ciMethod* dest_method) {

   // (Note:  TypeFunc::make has a cache that makes this fast.)

   const TypeFunc* tf    = TypeFunc::make(dest_method);

   int             nargs = tf->_domain->_cnt - TypeFunc::Parms;

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

     const Type *targ = tf->_domain->field_at(j + TypeFunc::Parms);

     if( targ->basic_type() == T_DOUBLE ) {

       // If any parameters are doubles, they must be rounded before

       // the call, dstore_rounding does gvn.transform

       Node *arg = argument(j);

       arg = dstore_rounding(arg);

       set_argument(j, arg);

     }

   }

 }

 void GraphKit::round_double_result(ciMethod* dest_method) {

   // A non-strict method may return a double value which has an extended

   // exponent, but this must not be visible in a caller which is 'strict'

   // If a strict caller invokes a non-strict callee, round a double result

   BasicType result_type = dest_method->return_type()->basic_type();

   assert( method() != NULL, "must have caller context");

   if( result_type == T_DOUBLE && method()->is_strict() && !dest_method->is_strict() ) {

     // Destination method's return value is on top of stack

     // dstore_rounding() does gvn.transform

     Node *result = pop_pair();

     result = dstore_rounding(result);

     push_pair(result);

   }

 }

 // rounding for strict float precision conformance

 Node* GraphKit::precision_rounding(Node* n) {

   return UseStrictFP && _method->flags().is_strict()

     && UseSSE == 0 && Matcher::strict_fp_requires_explicit_rounding

     ? _gvn.transform( new (C, 2) RoundFloatNode(0, n) )

     : n;

 }

 // rounding for strict double precision conformance

 Node* GraphKit::dprecision_rounding(Node *n) {

   return UseStrictFP && _method->flags().is_strict()

     && UseSSE <= 1 && Matcher::strict_fp_requires_explicit_rounding

     ? _gvn.transform( new (C, 2) RoundDoubleNode(0, n) )

     : n;

 }

 // rounding for non-strict double stores

 Node* GraphKit::dstore_rounding(Node* n) {

   return Matcher::strict_fp_requires_explicit_rounding

     && UseSSE <= 1

     ? _gvn.transform( new (C, 2) RoundDoubleNode(0, n) )

     : n;

 }

 //=============================================================================

 // Generate a fast path/slow path idiom.  Graph looks like:

 // [foo] indicates that 'foo' is a parameter

 //

 //              [in]     NULL

 //                 \    /

 //                  CmpP

 //                  Bool ne

 //                   If

 //                  /  \

 //              True    False-<2>

 //              / |

 //             /  cast_not_null

 //           Load  |    |   ^

 //        [fast_test]   |   |

 // gvn to   opt_test    |   |

 //          /    \      |  <1>

 //      True     False  |

 //        |         \\  |

 //   [slow_call]     \[fast_result]

 //    Ctl   Val       \      \

 //     |               \      \

 //    Catch       <1>   \      \

 //   /    \        ^     \      \

 //  Ex    No_Ex    |      \      \

 //  |       \   \  |       \ <2>  \

 //  ...      \  [slow_res] |  |    \   [null_result]

 //            \         \--+--+---  |  |

 //             \           | /    \ | /

 //              --------Region     Phi

 //

 //=============================================================================

 // Code is structured as a series of driver functions all called 'do_XXX' that

 // call a set of helper functions.  Helper functions first, then drivers.

 //------------------------------null_check_oop---------------------------------

 // Null check oop.  Set null-path control into Region in slot 3.

 // Make a cast-not-nullness use the other not-null control.  Return cast.

 Node* GraphKit::null_check_oop(Node* value, Node* *null_control,

                                bool never_see_null) {

   // Initial NULL check taken path

   (*null_control) = top();

   Node* cast = null_check_common(value, T_OBJECT, false, null_control);

   // Generate uncommon_trap:

   if (never_see_null && (*null_control) != top()) {

     // If we see an unexpected null at a check-cast we record it and force a

     // recompile; the offending check-cast will be compiled to handle NULLs.

     // If we see more than one offending BCI, then all checkcasts in the

     // method will be compiled to handle NULLs.

     PreserveJVMState pjvms(this);

     set_control(*null_control);

     replace_in_map(value, null());

     uncommon_trap(Deoptimization::Reason_null_check,

                   Deoptimization::Action_make_not_entrant);

     (*null_control) = top();    // NULL path is dead

   }

   // Cast away null-ness on the result

   return cast;

 }

 //------------------------------opt_iff----------------------------------------

 // Optimize the fast-check IfNode.  Set the fast-path region slot 2.

 // Return slow-path control.

 Node* GraphKit::opt_iff(Node* region, Node* iff) {

   IfNode *opt_iff = _gvn.transform(iff)->as_If();

   // Fast path taken; set region slot 2

   Node *fast_taken = _gvn.transform( new (C, 1) IfFalseNode(opt_iff) );

   region->init_req(2,fast_taken); // Capture fast-control

   // Fast path not-taken, i.e. slow path

   Node *slow_taken = _gvn.transform( new (C, 1) IfTrueNode(opt_iff) );

   return slow_taken;

 }

 //-----------------------------make_runtime_call-------------------------------

 Node* GraphKit::make_runtime_call(int flags,

                                   const TypeFunc* call_type, address call_addr,

                                   const char* call_name,

                                   const TypePtr* adr_type,

                                   // The following parms are all optional.

                                   // The first NULL ends the list.

                                   Node* parm0, Node* parm1,

                                   Node* parm2, Node* parm3,

                                   Node* parm4, Node* parm5,

                                   Node* parm6, Node* parm7) {

   // Slow-path call

   int size = call_type->domain()->cnt();

   bool is_leaf = !(flags & RC_NO_LEAF);

   bool has_io  = (!is_leaf && !(flags & RC_NO_IO));

   if (call_name == NULL) {

     assert(!is_leaf, "must supply name for leaf");

     call_name = OptoRuntime::stub_name(call_addr);

   }

   CallNode* call;

   if (!is_leaf) {

     call = new(C, size) CallStaticJavaNode(call_type, call_addr, call_name,

                                            bci(), adr_type);

   } else if (flags & RC_NO_FP) {

     call = new(C, size) CallLeafNoFPNode(call_type, call_addr, call_name, adr_type);

   } else {

     call = new(C, size) CallLeafNode(call_type, call_addr, call_name, adr_type);

   }

   // The following is similar to set_edges_for_java_call,

   // except that the memory effects of the call are restricted to AliasIdxRaw.

   // Slow path call has no side-effects, uses few values

   bool wide_in  = !(flags & RC_NARROW_MEM);

   bool wide_out = (C->get_alias_index(adr_type) == Compile::AliasIdxBot);

   Node* prev_mem = NULL;

   if (wide_in) {

     prev_mem = set_predefined_input_for_runtime_call(call);

   } else {

     assert(!wide_out, "narrow in => narrow out");

     Node* narrow_mem = memory(adr_type);

     prev_mem = reset_memory();

     map()->set_memory(narrow_mem);

     set_predefined_input_for_runtime_call(call);

   }

   // Hook each parm in order.  Stop looking at the first NULL.

   if (parm0 != NULL) { call->init_req(TypeFunc::Parms+0, parm0);

   if (parm1 != NULL) { call->init_req(TypeFunc::Parms+1, parm1);

   if (parm2 != NULL) { call->init_req(TypeFunc::Parms+2, parm2);

   if (parm3 != NULL) { call->init_req(TypeFunc::Parms+3, parm3);

   if (parm4 != NULL) { call->init_req(TypeFunc::Parms+4, parm4);

   if (parm5 != NULL) { call->init_req(TypeFunc::Parms+5, parm5);

   if (parm6 != NULL) { call->init_req(TypeFunc::Parms+6, parm6);

   if (parm7 != NULL) { call->init_req(TypeFunc::Parms+7, parm7);

     /* close each nested if ===> */  } } } } } } } }

   assert(call->in(call->req()-1) != NULL, "must initialize all parms");

   if (!is_leaf) {

     // Non-leaves can block and take safepoints:

     add_safepoint_edges(call, ((flags & RC_MUST_THROW) != 0));

   }

   // Non-leaves can throw exceptions:

   if (has_io) {

     call->set_req(TypeFunc::I_O, i_o());

   }

   if (flags & RC_UNCOMMON) {

     // Set the count to a tiny probability.  Cf. Estimate_Block_Frequency.

     // (An "if" probability corresponds roughly to an unconditional count.

     // Sort of.)

     call->set_cnt(PROB_UNLIKELY_MAG(4));

   }

   Node* c = _gvn.transform(call);

   assert(c == call, "cannot disappear");

   if (wide_out) {

     // Slow path call has full side-effects.

     set_predefined_output_for_runtime_call(call);

   } else {

     // Slow path call has few side-effects, and/or sets few values.

     set_predefined_output_for_runtime_call(call, prev_mem, adr_type);

   }

   if (has_io) {

     set_i_o(_gvn.transform(new (C, 1) ProjNode(call, TypeFunc::I_O)));

   }

   return call;

 }

 //------------------------------merge_memory-----------------------------------

 // Merge memory from one path into the current memory state.

 void GraphKit::merge_memory(Node* new_mem, Node* region, int new_path) {

   for (MergeMemStream mms(merged_memory(), new_mem->as_MergeMem()); mms.next_non_empty2(); ) {

     Node* old_slice = mms.force_memory();

     Node* new_slice = mms.memory2();

     if (old_slice != new_slice) {

       PhiNode* phi;

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

         phi = new_slice->as_Phi();

         #ifdef ASSERT

         if (old_slice->is_Phi() && old_slice->as_Phi()->region() == region)

           old_slice = old_slice->in(new_path);

         // Caller is responsible for ensuring that any pre-existing

         // phis are already aware of old memory.

         int old_path = (new_path > 1) ? 1 : 2;  // choose old_path != new_path

         assert(phi->in(old_path) == old_slice, "pre-existing phis OK");

         #endif

         mms.set_memory(phi);

       } else {

         phi = PhiNode::make(region, old_slice, Type::MEMORY, mms.adr_type(C));

         _gvn.set_type(phi, Type::MEMORY);

         phi->set_req(new_path, new_slice);

         mms.set_memory(_gvn.transform(phi));  // assume it is complete

       }

     }

   }

 }

 //------------------------------make_slow_call_ex------------------------------

 // Make the exception handler hookups for the slow call

 void GraphKit::make_slow_call_ex(Node* call, ciInstanceKlass* ex_klass, bool separate_io_proj) {

   if (stopped())  return;

   // Make a catch node with just two handlers:  fall-through and catch-all

   Node* i_o  = _gvn.transform( new (C, 1) ProjNode(call, TypeFunc::I_O, separate_io_proj) );

   Node* catc = _gvn.transform( new (C, 2) CatchNode(control(), i_o, 2) );

   Node* norm = _gvn.transform( new (C, 1) CatchProjNode(catc, CatchProjNode::fall_through_index, CatchProjNode::no_handler_bci) );

   Node* excp = _gvn.transform( new (C, 1) CatchProjNode(catc, CatchProjNode::catch_all_index,    CatchProjNode::no_handler_bci) );

   { PreserveJVMState pjvms(this);

     set_control(excp);

     set_i_o(i_o);

     if (excp != top()) {

       // Create an exception state also.

       // Use an exact type if the caller has specified a specific exception.

       const Type* ex_type = TypeOopPtr::make_from_klass_unique(ex_klass)->cast_to_ptr_type(TypePtr::NotNull);

       Node*       ex_oop  = new (C, 2) CreateExNode(ex_type, control(), i_o);

       add_exception_state(make_exception_state(_gvn.transform(ex_oop)));

     }

   }

   // Get the no-exception control from the CatchNode.

   set_control(norm);

 }

 //-------------------------------gen_subtype_check-----------------------------

 // Generate a subtyping check.  Takes as input the subtype and supertype.

 // Returns 2 values: sets the default control() to the true path and returns

 // the false path.  Only reads invariant memory; sets no (visible) memory.

 // The PartialSubtypeCheckNode sets the hidden 1-word cache in the encoding

 // but that's not exposed to the optimizer.  This call also doesn't take in an

 // Object; if you wish to check an Object you need to load the Object's class

 // prior to coming here.

 Node* GraphKit::gen_subtype_check(Node* subklass, Node* superklass) {

   // Fast check for identical types, perhaps identical constants.

   // The types can even be identical non-constants, in cases

   // involving Array.newInstance, Object.clone, etc.

   if (subklass == superklass)

     return top();             // false path is dead; no test needed.

   if (_gvn.type(superklass)->singleton()) {

     ciKlass* superk = _gvn.type(superklass)->is_klassptr()->klass();

     ciKlass* subk   = _gvn.type(subklass)->is_klassptr()->klass();

     // In the common case of an exact superklass, try to fold up the

     // test before generating code.  You may ask, why not just generate

     // the code and then let it fold up?  The answer is that the generated

     // code will necessarily include null checks, which do not always

     // completely fold away.  If they are also needless, then they turn

     // into a performance loss.  Example:

     //    Foo[] fa = blah(); Foo x = fa[0]; fa[1] = x;

     // Here, the type of 'fa' is often exact, so the store check

     // of fa[1]=x will fold up, without testing the nullness of x.

     switch (static_subtype_check(superk, subk)) {

     case SSC_always_false:

       {

         Node* always_fail = control();

         set_control(top());

         return always_fail;

       }

     case SSC_always_true:

       return top();

     case SSC_easy_test:

       {

         // Just do a direct pointer compare and be done.

         Node* cmp = _gvn.transform( new(C, 3) CmpPNode(subklass, superklass) );

         Node* bol = _gvn.transform( new(C, 2) BoolNode(cmp, BoolTest::eq) );

         IfNode* iff = create_and_xform_if(control(), bol, PROB_STATIC_FREQUENT, COUNT_UNKNOWN);

         set_control( _gvn.transform( new(C, 1) IfTrueNode (iff) ) );

         return       _gvn.transform( new(C, 1) IfFalseNode(iff) );

       }

     case SSC_full_test:

       break;

     default:

       ShouldNotReachHere();

     }

   }

   // %%% Possible further optimization:  Even if the superklass is not exact,

   // if the subklass is the unique subtype of the superklass, the check

   // will always succeed.  We could leave a dependency behind to ensure this.

   // First load the super-klass's check-offset

   Node *p1 = basic_plus_adr( superklass, superklass, sizeof(oopDesc) + Klass::super_check_offset_offset_in_bytes() );

   Node *chk_off = _gvn.transform( new (C, 3) LoadINode( NULL, memory(p1), p1, _gvn.type(p1)->is_ptr() ) );

   int cacheoff_con = sizeof(oopDesc) + Klass::secondary_super_cache_offset_in_bytes();

   bool might_be_cache = (find_int_con(chk_off, cacheoff_con) == cacheoff_con);

   // Load from the sub-klass's super-class display list, or a 1-word cache of

   // the secondary superclass list, or a failing value with a sentinel offset

   // if the super-klass is an interface or exceptionally deep in the Java

   // hierarchy and we have to scan the secondary superclass list the hard way.

   // Worst-case type is a little odd: NULL is allowed as a result (usually

   // klass loads can never produce a NULL).

   Node *chk_off_X = ConvI2X(chk_off);

   Node *p2 = _gvn.transform( new (C, 4) AddPNode(subklass,subklass,chk_off_X) );

   // For some types like interfaces the following loadKlass is from a 1-word

   // cache which is mutable so can't use immutable memory.  Other

   // types load from the super-class display table which is immutable.

   Node *kmem = might_be_cache ? memory(p2) : immutable_memory();

   Node *nkls = _gvn.transform( LoadKlassNode::make( _gvn, kmem, p2, _gvn.type(p2)->is_ptr(), TypeKlassPtr::OBJECT_OR_NULL ) );

   // Compile speed common case: ARE a subtype and we canNOT fail

   if( superklass == nkls )

     return top();             // false path is dead; no test needed.

   // See if we get an immediate positive hit.  Happens roughly 83% of the

   // time.  Test to see if the value loaded just previously from the subklass

   // is exactly the superklass.

   Node *cmp1 = _gvn.transform( new (C, 3) CmpPNode( superklass, nkls ) );

   Node *bol1 = _gvn.transform( new (C, 2) BoolNode( cmp1, BoolTest::eq ) );

   IfNode *iff1 = create_and_xform_if( control(), bol1, PROB_LIKELY(0.83f), COUNT_UNKNOWN );

   Node *iftrue1 = _gvn.transform( new (C, 1) IfTrueNode ( iff1 ) );

   set_control(    _gvn.transform( new (C, 1) IfFalseNode( iff1 ) ) );

   // Compile speed common case: Check for being deterministic right now.  If

   // chk_off is a constant and not equal to cacheoff then we are NOT a

   // subklass.  In this case we need exactly the 1 test above and we can

   // return those results immediately.

   if (!might_be_cache) {

     Node* not_subtype_ctrl = control();

     set_control(iftrue1); // We need exactly the 1 test above

     return not_subtype_ctrl;

   }

   // Gather the various success & failures here

   RegionNode *r_ok_subtype = new (C, 4) RegionNode(4);

   record_for_igvn(r_ok_subtype);

   RegionNode *r_not_subtype = new (C, 3) RegionNode(3);

   record_for_igvn(r_not_subtype);

   r_ok_subtype->init_req(1, iftrue1);

   // Check for immediate negative hit.  Happens roughly 11% of the time (which

   // is roughly 63% of the remaining cases).  Test to see if the loaded

   // check-offset points into the subklass display list or the 1-element

   // cache.  If it points to the display (and NOT the cache) and the display

   // missed then it's not a subtype.

   Node *cacheoff = _gvn.intcon(cacheoff_con);

   Node *cmp2 = _gvn.transform( new (C, 3) CmpINode( chk_off, cacheoff ) );

   Node *bol2 = _gvn.transform( new (C, 2) BoolNode( cmp2, BoolTest::ne ) );

   IfNode *iff2 = create_and_xform_if( control(), bol2, PROB_LIKELY(0.63f), COUNT_UNKNOWN );

   r_not_subtype->init_req(1, _gvn.transform( new (C, 1) IfTrueNode (iff2) ) );

   set_control(                _gvn.transform( new (C, 1) IfFalseNode(iff2) ) );

   // Check for self.  Very rare to get here, but its taken 1/3 the time.

   // No performance impact (too rare) but allows sharing of secondary arrays

   // which has some footprint reduction.

   Node *cmp3 = _gvn.transform( new (C, 3) CmpPNode( subklass, superklass ) );

   Node *bol3 = _gvn.transform( new (C, 2) BoolNode( cmp3, BoolTest::eq ) );

   IfNode *iff3 = create_and_xform_if( control(), bol3, PROB_LIKELY(0.36f), COUNT_UNKNOWN );

   r_ok_subtype->init_req(2, _gvn.transform( new (C, 1) IfTrueNode ( iff3 ) ) );

   set_control(               _gvn.transform( new (C, 1) IfFalseNode( iff3 ) ) );

   // Now do a linear scan of the secondary super-klass array.  Again, no real

   // performance impact (too rare) but it's gotta be done.

   // (The stub also contains the self-check of subklass == superklass.

   // Since the code is rarely used, there is no penalty for moving it

   // out of line, and it can only improve I-cache density.)

   Node* psc = _gvn.transform(

     new (C, 3) PartialSubtypeCheckNode(control(), subklass, superklass) );

   Node *cmp4 = _gvn.transform( new (C, 3) CmpPNode( psc, null() ) );

   Node *bol4 = _gvn.transform( new (C, 2) BoolNode( cmp4, BoolTest::ne ) );

   IfNode *iff4 = create_and_xform_if( control(), bol4, PROB_FAIR, COUNT_UNKNOWN );

   r_not_subtype->init_req(2, _gvn.transform( new (C, 1) IfTrueNode (iff4) ) );

   r_ok_subtype ->init_req(3, _gvn.transform( new (C, 1) IfFalseNode(iff4) ) );

   // Return false path; set default control to true path.

   set_control( _gvn.transform(r_ok_subtype) );

   return _gvn.transform(r_not_subtype);

 }

 //----------------------------static_subtype_check-----------------------------

 // Shortcut important common cases when superklass is exact:

 // (0) superklass is java.lang.Object (can occur in reflective code)

 // (1) subklass is already limited to a subtype of superklass => always ok

 // (2) subklass does not overlap with superklass => always fail

 // (3) superklass has NO subtypes and we can check with a simple compare.

 int GraphKit::static_subtype_check(ciKlass* superk, ciKlass* subk) {

   if (StressReflectiveCode) {

     return SSC_full_test;       // Let caller generate the general case.

   }

   if (superk == env()->Object_klass()) {

     return SSC_always_true;     // (0) this test cannot fail

   }

   ciType* superelem = superk;

   if (superelem->is_array_klass())

     superelem = superelem->as_array_klass()->base_element_type();

   if (!subk->is_interface()) {  // cannot trust static interface types yet

     if (subk->is_subtype_of(superk)) {

       return SSC_always_true;   // (1) false path dead; no dynamic test needed

     }

     if (!(superelem->is_klass() && superelem->as_klass()->is_interface()) &&

         !superk->is_subtype_of(subk)) {

       return SSC_always_false;

     }

   }

   // If casting to an instance klass, it must have no subtypes

   if (superk->is_interface()) {

     // Cannot trust interfaces yet.

     // %%% S.B. superk->nof_implementors() == 1

   } else if (superelem->is_instance_klass()) {

     ciInstanceKlass* ik = superelem->as_instance_klass();

     if (!ik->has_subklass() && !ik->is_interface()) {

       if (!ik->is_final()) {

         // Add a dependency if there is a chance of a later subclass.

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

       }

       return SSC_easy_test;     // (3) caller can do a simple ptr comparison

     }

   } else {

     // A primitive array type has no subtypes.

     return SSC_easy_test;       // (3) caller can do a simple ptr comparison

   }

   return SSC_full_test;

 }

 // Profile-driven exact type check:

 Node* GraphKit::type_check_receiver(Node* receiver, ciKlass* klass,

                                     float prob,

                                     Node* *casted_receiver) {

   const TypeKlassPtr* tklass = TypeKlassPtr::make(klass);

   Node* recv_klass = load_object_klass(receiver);

   Node* want_klass = makecon(tklass);

   Node* cmp = _gvn.transform( new(C, 3) CmpPNode(recv_klass, want_klass) );

   Node* bol = _gvn.transform( new(C, 2) BoolNode(cmp, BoolTest::eq) );

   IfNode* iff = create_and_xform_if(control(), bol, prob, COUNT_UNKNOWN);

   set_control( _gvn.transform( new(C, 1) IfTrueNode (iff) ));

   Node* fail = _gvn.transform( new(C, 1) IfFalseNode(iff) );

   const TypeOopPtr* recv_xtype = tklass->as_instance_type();

   assert(recv_xtype->klass_is_exact(), "");

   // Subsume downstream occurrences of receiver with a cast to

   // recv_xtype, since now we know what the type will be.

   Node* cast = new(C, 2) CheckCastPPNode(control(), receiver, recv_xtype);

   (*casted_receiver) = _gvn.transform(cast);

   // (User must make the replace_in_map call.)

   return fail;

 }

 //-------------------------------gen_instanceof--------------------------------

 // Generate an instance-of idiom.  Used by both the instance-of bytecode

 // and the reflective instance-of call.

 Node* GraphKit::gen_instanceof( Node *subobj, Node* superklass ) {

   C->set_has_split_ifs(true); // Has chance for split-if optimization

   assert( !stopped(), "dead parse path should be checked in callers" );

   assert(!TypePtr::NULL_PTR->higher_equal(_gvn.type(superklass)->is_klassptr()),

          "must check for not-null not-dead klass in callers");

   // Make the merge point

   enum { _obj_path = 1, _fail_path, _null_path, PATH_LIMIT };

   RegionNode* region = new(C, PATH_LIMIT) RegionNode(PATH_LIMIT);

   Node*       phi    = new(C, PATH_LIMIT) PhiNode(region, TypeInt::BOOL);

   C->set_has_split_ifs(true); // Has chance for split-if optimization

   // Null check; get casted pointer; set region slot 3

   Node* null_ctl = top();

   Node* not_null_obj = null_check_oop(subobj, &null_ctl);

   // If not_null_obj is dead, only null-path is taken

   if (stopped()) {              // Doing instance-of on a NULL?

     set_control(null_ctl);

     return intcon(0);

   }

   region->init_req(_null_path, null_ctl);

   phi   ->init_req(_null_path, intcon(0)); // Set null path value

   // Load the object's klass

   Node* obj_klass = load_object_klass(not_null_obj);

   // Generate the subtype check

   Node* not_subtype_ctrl = gen_subtype_check(obj_klass, superklass);

   // Plug in the success path to the general merge in slot 1.

   region->init_req(_obj_path, control());

   phi   ->init_req(_obj_path, intcon(1));

   // Plug in the failing path to the general merge in slot 2.

   region->init_req(_fail_path, not_subtype_ctrl);

   phi   ->init_req(_fail_path, intcon(0));

   // Return final merged results

   set_control( _gvn.transform(region) );

   record_for_igvn(region);

   return _gvn.transform(phi);

 }

 //-------------------------------gen_checkcast---------------------------------

 // Generate a checkcast idiom.  Used by both the checkcast bytecode and the

 // array store bytecode.  Stack must be as-if BEFORE doing the bytecode so the

 // uncommon-trap paths work.  Adjust stack after this call.

 // If failure_control is supplied and not null, it is filled in with

 // the control edge for the cast failure.  Otherwise, an appropriate

 // uncommon trap or exception is thrown.

 Node* GraphKit::gen_checkcast(Node *obj, Node* superklass,

                               Node* *failure_control) {

   kill_dead_locals();           // Benefit all the uncommon traps

   const TypeKlassPtr *tk = _gvn.type(superklass)->is_klassptr();

   const Type *toop = TypeOopPtr::make_from_klass(tk->klass());

   // Fast cutout:  Check the case that the cast is vacuously true.

   // This detects the common cases where the test will short-circuit

   // away completely.  We do this before we perform the null check,

   // because if the test is going to turn into zero code, we don't

   // want a residual null check left around.  (Causes a slowdown,

   // for example, in some objArray manipulations, such as a[i]=a[j].)

   if (tk->singleton()) {

     const TypeOopPtr* objtp = _gvn.type(obj)->isa_oopptr();

     if (objtp != NULL && objtp->klass() != NULL) {

       switch (static_subtype_check(tk->klass(), objtp->klass())) {

       case SSC_always_true:

         return obj;

       case SSC_always_false:

         // It needs a null check because a null will *pass* the cast check.

         // A non-null value will always produce an exception.

         return do_null_assert(obj, T_OBJECT);

       }

     }

   }

   ciProfileData* data = NULL;

   if (failure_control == NULL) {        // use MDO in regular case only

     assert(java_bc() == Bytecodes::_aastore ||

            java_bc() == Bytecodes::_checkcast,

            "interpreter profiles type checks only for these BCs");

     data = method()->method_data()->bci_to_data(bci());

   }

   // Make the merge point

   enum { _obj_path = 1, _null_path, PATH_LIMIT };

   RegionNode* region = new (C, PATH_LIMIT) RegionNode(PATH_LIMIT);

   Node*       phi    = new (C, PATH_LIMIT) PhiNode(region, toop);

   C->set_has_split_ifs(true); // Has chance for split-if optimization

   // Use null-cast information if it is available

   bool never_see_null = false;

   // If we see an unexpected null at a check-cast we record it and force a

   // recompile; the offending check-cast will be compiled to handle NULLs.

   // If we see several offending BCIs, then all checkcasts in the

   // method will be compiled to handle NULLs.

   if (UncommonNullCast            // Cutout for this technique

       && failure_control == NULL  // regular case

       && obj != null()            // And not the -Xcomp stupid case?

       && !too_many_traps(Deoptimization::Reason_null_check)) {

     // Finally, check the "null_seen" bit from the interpreter.

     if (data == NULL || !data->as_BitData()->null_seen()) {

       never_see_null = true;

     }

   }

   // Null check; get casted pointer; set region slot 3

   Node* null_ctl = top();

   Node* not_null_obj = null_check_oop(obj, &null_ctl, never_see_null);

   // If not_null_obj is dead, only null-path is taken

   if (stopped()) {              // Doing instance-of on a NULL?

     set_control(null_ctl);

     return null();

   }

   region->init_req(_null_path, null_ctl);

   phi   ->init_req(_null_path, null());  // Set null path value

   Node* cast_obj = NULL;        // the casted version of the object

   // If the profile has seen exactly one type, narrow to that type.

   // (The subsequent subtype check will always fold up.)

   if (UseTypeProfile && TypeProfileCasts && data != NULL &&

       // Counter has never been decremented (due to cast failure).

       // ...This is a reasonable thing to expect.  It is true of

       // all casts inserted by javac to implement generic types.

       data->as_CounterData()->count() >= 0 &&

       !too_many_traps(Deoptimization::Reason_class_check)) {

     // (No, this isn't a call, but it's enough like a virtual call

     // to use the same ciMethod accessor to get the profile info...)

     ciCallProfile profile = method()->call_profile_at_bci(bci());

     if (profile.count() >= 0 &&         // no cast failures here

         profile.has_receiver(0) &&

         profile.morphism() == 1) {

       ciKlass* exact_kls = profile.receiver(0);

       int ssc = static_subtype_check(tk->klass(), exact_kls);

       if (ssc == SSC_always_true) {

         // If we narrow the type to match what the type profile sees,

         // we can then remove the rest of the cast.

         // This is a win, even if the exact_kls is very specific,

         // because downstream operations, such as method calls,

         // will often benefit from the sharper type.

         Node* exact_obj = not_null_obj; // will get updated in place...

         Node* slow_ctl  = type_check_receiver(exact_obj, exact_kls, 1.0,

                                               &exact_obj);

         { PreserveJVMState pjvms(this);

           set_control(slow_ctl);

           uncommon_trap(Deoptimization::Reason_class_check,

                         Deoptimization::Action_maybe_recompile);

         }

         if (failure_control != NULL) // failure is now impossible

           (*failure_control) = top();

         replace_in_map(not_null_obj, exact_obj);

         // adjust the type of the phi to the exact klass:

         phi->raise_bottom_type(_gvn.type(exact_obj)->meet(TypePtr::NULL_PTR));

         cast_obj = exact_obj;

       }

       // assert(cast_obj != NULL)... except maybe the profile lied to us.

     }

   }

   if (cast_obj == NULL) {

     // Load the object's klass

     Node* obj_klass = load_object_klass(not_null_obj);

     // Generate the subtype check

     Node* not_subtype_ctrl = gen_subtype_check( obj_klass, superklass );

     // Plug in success path into the merge

     cast_obj = _gvn.transform(new (C, 2) CheckCastPPNode(control(),

                                                          not_null_obj, toop));

     // Failure path ends in uncommon trap (or may be dead - failure impossible)

     if (failure_control == NULL) {

       if (not_subtype_ctrl != top()) { // If failure is possible

         PreserveJVMState pjvms(this);

         set_control(not_subtype_ctrl);

         builtin_throw(Deoptimization::Reason_class_check, obj_klass);

       }

     } else {

       (*failure_control) = not_subtype_ctrl;

     }

   }

   region->init_req(_obj_path, control());

   phi   ->init_req(_obj_path, cast_obj);

   // A merge of NULL or Casted-NotNull obj

   Node* res = _gvn.transform(phi);

   // Note I do NOT always 'replace_in_map(obj,result)' here.

   //  if( tk->klass()->can_be_primary_super()  )

     // This means that if I successfully store an Object into an array-of-String

     // I 'forget' that the Object is really now known to be a String.  I have to

     // do this because we don't have true union types for interfaces - if I store

     // a Baz into an array-of-Interface and then tell the optimizer it's an

     // Interface, I forget that it's also a Baz and cannot do Baz-like field

     // references to it.  FIX THIS WHEN UNION TYPES APPEAR!

   //  replace_in_map( obj, res );

   // Return final merged results

   set_control( _gvn.transform(region) );

   record_for_igvn(region);

   return res;

 }

 //------------------------------next_monitor-----------------------------------

 // What number should be given to the next monitor?

 int GraphKit::next_monitor() {

   int current = jvms()->monitor_depth()* C->sync_stack_slots();

   int next = current + C->sync_stack_slots();

   // Keep the toplevel high water mark current:

   if (C->fixed_slots() < next)  C->set_fixed_slots(next);

   return current;

 }

 //------------------------------insert_mem_bar---------------------------------

 // Memory barrier to avoid floating things around

 // The membar serves as a pinch point between both control and all memory slices.

 Node* GraphKit::insert_mem_bar(int opcode, Node* precedent) {

   MemBarNode* mb = MemBarNode::make(C, opcode, Compile::AliasIdxBot, precedent);

   mb->init_req(TypeFunc::Control, control());

   mb->init_req(TypeFunc::Memory,  reset_memory());

   Node* membar = _gvn.transform(mb);

   set_control(_gvn.transform(new (C, 1) ProjNode(membar,TypeFunc::Control) ));

   set_all_memory_call(membar);

   return membar;

 }

 //-------------------------insert_mem_bar_volatile----------------------------

 // Memory barrier to avoid floating things around

 // The membar serves as a pinch point between both control and memory(alias_idx).

 // If you want to make a pinch point on all memory slices, do not use this

 // function (even with AliasIdxBot); use insert_mem_bar() instead.

 Node* GraphKit::insert_mem_bar_volatile(int opcode, int alias_idx, Node* precedent) {

   // When Parse::do_put_xxx updates a volatile field, it appends a series

   // of MemBarVolatile nodes, one for *each* volatile field alias category.

   // The first membar is on the same memory slice as the field store opcode.

   // This forces the membar to follow the store.  (Bug 6500685 broke this.)

   // All the other membars (for other volatile slices, including AliasIdxBot,

   // which stands for all unknown volatile slices) are control-dependent

   // on the first membar.  This prevents later volatile loads or stores

   // from sliding up past the just-emitted store.

   MemBarNode* mb = MemBarNode::make(C, opcode, alias_idx, precedent);

   mb->set_req(TypeFunc::Control,control());

   if (alias_idx == Compile::AliasIdxBot) {

     mb->set_req(TypeFunc::Memory, merged_memory()->base_memory());

   } else {

     assert(!(opcode == Op_Initialize && alias_idx != Compile::AliasIdxRaw), "fix caller");

     mb->set_req(TypeFunc::Memory, memory(alias_idx));

   }

   Node* membar = _gvn.transform(mb);

   set_control(_gvn.transform(new (C, 1) ProjNode(membar, TypeFunc::Control)));

   if (alias_idx == Compile::AliasIdxBot) {

     merged_memory()->set_base_memory(_gvn.transform(new (C, 1) ProjNode(membar, TypeFunc::Memory)));

   } else {

     set_memory(_gvn.transform(new (C, 1) ProjNode(membar, TypeFunc::Memory)),alias_idx);

   }

   return membar;

 }

 //------------------------------shared_lock------------------------------------

 // Emit locking code.

 FastLockNode* GraphKit::shared_lock(Node* obj) {

   // bci is either a monitorenter bc or InvocationEntryBci

   // %%% SynchronizationEntryBCI is redundant; use InvocationEntryBci in interfaces

   assert(SynchronizationEntryBCI == InvocationEntryBci, "");

   if( !GenerateSynchronizationCode )

     return NULL;                // Not locking things?

   if (stopped())                // Dead monitor?

     return NULL;

   assert(dead_locals_are_killed(), "should kill locals before sync. point");

   // Box the stack location