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

 /*

  * Copyright (c) 1997, 2018, Oracle and/or its affiliates. All rights reserved.

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

  *

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

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

  * published by the Free Software Foundation.

  *

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

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

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

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

  * accompanied this code).

  *

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

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

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

  *

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

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

  * questions.

  *

  */

 #include "precompiled.hpp"

 #include "asm/macroAssembler.hpp"

 #include "asm/macroAssembler.inline.hpp"

 #include "ci/ciReplay.hpp"

 #include "classfile/systemDictionary.hpp"

 #include "code/exceptionHandlerTable.hpp"

 #include "code/nmethod.hpp"

 #include "compiler/compileLog.hpp"

 #include "compiler/disassembler.hpp"

 #include "compiler/oopMap.hpp"

 #include "jfr/jfrEvents.hpp"

 #include "opto/addnode.hpp"

 #include "opto/block.hpp"

 #include "opto/c2compiler.hpp"

 #include "opto/callGenerator.hpp"

 #include "opto/callnode.hpp"

 #include "opto/cfgnode.hpp"

 #include "opto/chaitin.hpp"

 #include "opto/compile.hpp"

 #include "opto/connode.hpp"

 #include "opto/divnode.hpp"

 #include "opto/escape.hpp"

 #include "opto/idealGraphPrinter.hpp"

 #include "opto/loopnode.hpp"

 #include "opto/machnode.hpp"

 #include "opto/macro.hpp"

 #include "opto/matcher.hpp"

 #include "opto/mathexactnode.hpp"

 #include "opto/memnode.hpp"

 #include "opto/mulnode.hpp"

 #include "opto/node.hpp"

 #include "opto/opcodes.hpp"

 #include "opto/output.hpp"

 #include "opto/parse.hpp"

 #include "opto/phaseX.hpp"

 #include "opto/rootnode.hpp"

 #include "opto/runtime.hpp"

 #include "opto/stringopts.hpp"

 #include "opto/type.hpp"

 #include "opto/vectornode.hpp"

 #include "runtime/arguments.hpp"

 #include "runtime/signature.hpp"

 #include "runtime/stubRoutines.hpp"

 #include "runtime/timer.hpp"

 #include "utilities/copy.hpp"

 #if defined AD_MD_HPP

 # include AD_MD_HPP

 #elif defined TARGET_ARCH_MODEL_x86_32

 # include "adfiles/ad_x86_32.hpp"

 #elif defined TARGET_ARCH_MODEL_x86_64

 # include "adfiles/ad_x86_64.hpp"

 #elif defined TARGET_ARCH_MODEL_sparc

 # include "adfiles/ad_sparc.hpp"

 #elif defined TARGET_ARCH_MODEL_zero

 # include "adfiles/ad_zero.hpp"

 #elif defined TARGET_ARCH_MODEL_ppc_64

 # include "adfiles/ad_ppc_64.hpp"

 #endif

 // -------------------- Compile::mach_constant_base_node -----------------------

 // Constant table base node singleton.

 MachConstantBaseNode* Compile::mach_constant_base_node() {

   if (_mach_constant_base_node == NULL) {

     _mach_constant_base_node = new (C) MachConstantBaseNode();

     _mach_constant_base_node->add_req(C->root());

   }

   return _mach_constant_base_node;

 }

 /// Support for intrinsics.

 // Return the index at which m must be inserted (or already exists).

 // The sort order is by the address of the ciMethod, with is_virtual as minor key.

 int Compile::intrinsic_insertion_index(ciMethod* m, bool is_virtual) {

 #ifdef ASSERT

   for (int i = 1; i < _intrinsics->length(); i++) {

     CallGenerator* cg1 = _intrinsics->at(i-1);

     CallGenerator* cg2 = _intrinsics->at(i);

     assert(cg1->method() != cg2->method()

            ? cg1->method()     < cg2->method()

            : cg1->is_virtual() < cg2->is_virtual(),

            "compiler intrinsics list must stay sorted");

   }

 #endif

   // Binary search sorted list, in decreasing intervals [lo, hi].

   int lo = 0, hi = _intrinsics->length()-1;

   while (lo <= hi) {

     int mid = (uint)(hi + lo) / 2;

     ciMethod* mid_m = _intrinsics->at(mid)->method();

     if (m < mid_m) {

       hi = mid-1;

     } else if (m > mid_m) {

       lo = mid+1;

     } else {

       // look at minor sort key

       bool mid_virt = _intrinsics->at(mid)->is_virtual();

       if (is_virtual < mid_virt) {

         hi = mid-1;

       } else if (is_virtual > mid_virt) {

         lo = mid+1;

       } else {

         return mid;  // exact match

       }

     }

   }

   return lo;  // inexact match

 }

 void Compile::register_intrinsic(CallGenerator* cg) {

   if (_intrinsics == NULL) {

     _intrinsics = new (comp_arena())GrowableArray<CallGenerator*>(comp_arena(), 60, 0, NULL);

   }

   // This code is stolen from ciObjectFactory::insert.

   // Really, GrowableArray should have methods for

   // insert_at, remove_at, and binary_search.

   int len = _intrinsics->length();

   int index = intrinsic_insertion_index(cg->method(), cg->is_virtual());

   if (index == len) {

     _intrinsics->append(cg);

   } else {

 #ifdef ASSERT

     CallGenerator* oldcg = _intrinsics->at(index);

     assert(oldcg->method() != cg->method() || oldcg->is_virtual() != cg->is_virtual(), "don't register twice");

 #endif

     _intrinsics->append(_intrinsics->at(len-1));

     int pos;

     for (pos = len-2; pos >= index; pos--) {

       _intrinsics->at_put(pos+1,_intrinsics->at(pos));

     }

     _intrinsics->at_put(index, cg);

   }

   assert(find_intrinsic(cg->method(), cg->is_virtual()) == cg, "registration worked");

 }

 CallGenerator* Compile::find_intrinsic(ciMethod* m, bool is_virtual) {

   assert(m->is_loaded(), "don't try this on unloaded methods");

   if (_intrinsics != NULL) {

     int index = intrinsic_insertion_index(m, is_virtual);

     if (index < _intrinsics->length()

         && _intrinsics->at(index)->method() == m

         && _intrinsics->at(index)->is_virtual() == is_virtual) {

       return _intrinsics->at(index);

     }

   }

   // Lazily create intrinsics for intrinsic IDs well-known in the runtime.

   if (m->intrinsic_id() != vmIntrinsics::_none &&

       m->intrinsic_id() <= vmIntrinsics::LAST_COMPILER_INLINE) {

     CallGenerator* cg = make_vm_intrinsic(m, is_virtual);

     if (cg != NULL) {

       // Save it for next time:

       register_intrinsic(cg);

       return cg;

     } else {

       gather_intrinsic_statistics(m->intrinsic_id(), is_virtual, _intrinsic_disabled);

     }

   }

   return NULL;

 }

 // Compile:: register_library_intrinsics and make_vm_intrinsic are defined

 // in library_call.cpp.

 #ifndef PRODUCT

 // statistics gathering...

 juint  Compile::_intrinsic_hist_count[vmIntrinsics::ID_LIMIT] = {0};

 jubyte Compile::_intrinsic_hist_flags[vmIntrinsics::ID_LIMIT] = {0};

 bool Compile::gather_intrinsic_statistics(vmIntrinsics::ID id, bool is_virtual, int flags) {

   assert(id > vmIntrinsics::_none && id < vmIntrinsics::ID_LIMIT, "oob");

   int oflags = _intrinsic_hist_flags[id];

   assert(flags != 0, "what happened?");

   if (is_virtual) {

     flags |= _intrinsic_virtual;

   }

   bool changed = (flags != oflags);

   if ((flags & _intrinsic_worked) != 0) {

     juint count = (_intrinsic_hist_count[id] += 1);

     if (count == 1) {

       changed = true;           // first time

     }

     // increment the overall count also:

     _intrinsic_hist_count[vmIntrinsics::_none] += 1;

   }

   if (changed) {

     if (((oflags ^ flags) & _intrinsic_virtual) != 0) {

       // Something changed about the intrinsic's virtuality.

       if ((flags & _intrinsic_virtual) != 0) {

         // This is the first use of this intrinsic as a virtual call.

         if (oflags != 0) {

           // We already saw it as a non-virtual, so note both cases.

           flags |= _intrinsic_both;

         }

       } else if ((oflags & _intrinsic_both) == 0) {

         // This is the first use of this intrinsic as a non-virtual

         flags |= _intrinsic_both;

       }

     }

     _intrinsic_hist_flags[id] = (jubyte) (oflags | flags);

   }

   // update the overall flags also:

   _intrinsic_hist_flags[vmIntrinsics::_none] |= (jubyte) flags;

   return changed;

 }

 static char* format_flags(int flags, char* buf) {

   buf[0] = 0;

   if ((flags & Compile::_intrinsic_worked) != 0)    strcat(buf, ",worked");

   if ((flags & Compile::_intrinsic_failed) != 0)    strcat(buf, ",failed");

   if ((flags & Compile::_intrinsic_disabled) != 0)  strcat(buf, ",disabled");

   if ((flags & Compile::_intrinsic_virtual) != 0)   strcat(buf, ",virtual");

   if ((flags & Compile::_intrinsic_both) != 0)      strcat(buf, ",nonvirtual");

   if (buf[0] == 0)  strcat(buf, ",");

   assert(buf[0] == ',', "must be");

   return &buf[1];

 }

 void Compile::print_intrinsic_statistics() {

   char flagsbuf[100];

   ttyLocker ttyl;

   if (xtty != NULL)  xtty->head("statistics type='intrinsic'");

   tty->print_cr("Compiler intrinsic usage:");

   juint total = _intrinsic_hist_count[vmIntrinsics::_none];

   if (total == 0)  total = 1;  // avoid div0 in case of no successes

   #define PRINT_STAT_LINE(name, c, f) \

     tty->print_cr("  %4d (%4.1f%%) %s (%s)", (int)(c), ((c) * 100.0) / total, name, f);

   for (int index = 1 + (int)vmIntrinsics::_none; index < (int)vmIntrinsics::ID_LIMIT; index++) {

     vmIntrinsics::ID id = (vmIntrinsics::ID) index;

     int   flags = _intrinsic_hist_flags[id];

     juint count = _intrinsic_hist_count[id];

     if ((flags | count) != 0) {

       PRINT_STAT_LINE(vmIntrinsics::name_at(id), count, format_flags(flags, flagsbuf));

     }

   }

   PRINT_STAT_LINE("total", total, format_flags(_intrinsic_hist_flags[vmIntrinsics::_none], flagsbuf));

   if (xtty != NULL)  xtty->tail("statistics");

 }

 void Compile::print_statistics() {

   { ttyLocker ttyl;

     if (xtty != NULL)  xtty->head("statistics type='opto'");

     Parse::print_statistics();

     PhaseCCP::print_statistics();

     PhaseRegAlloc::print_statistics();

     Scheduling::print_statistics();

     PhasePeephole::print_statistics();

     PhaseIdealLoop::print_statistics();

     if (xtty != NULL)  xtty->tail("statistics");

   }

   if (_intrinsic_hist_flags[vmIntrinsics::_none] != 0) {

     // put this under its own <statistics> element.

     print_intrinsic_statistics();

   }

 }

 #endif //PRODUCT

 // Support for bundling info

 Bundle* Compile::node_bundling(const Node *n) {

   assert(valid_bundle_info(n), "oob");

   return &_node_bundling_base[n->_idx];

 }

 bool Compile::valid_bundle_info(const Node *n) {

   return (_node_bundling_limit > n->_idx);

 }

 void Compile::gvn_replace_by(Node* n, Node* nn) {

   for (DUIterator_Last imin, i = n->last_outs(imin); i >= imin; ) {

     Node* use = n->last_out(i);

     bool is_in_table = initial_gvn()->hash_delete(use);

     uint uses_found = 0;

     for (uint j = 0; j < use->len(); j++) {

       if (use->in(j) == n) {

         if (j < use->req())

           use->set_req(j, nn);

         else

           use->set_prec(j, nn);

         uses_found++;

       }

     }

     if (is_in_table) {

       // reinsert into table

       initial_gvn()->hash_find_insert(use);

     }

     record_for_igvn(use);

     i -= uses_found;    // we deleted 1 or more copies of this edge

   }

 }

 static inline bool not_a_node(const Node* n) {

   if (n == NULL)                   return true;

   if (((intptr_t)n & 1) != 0)      return true;  // uninitialized, etc.

   if (*(address*)n == badAddress)  return true;  // kill by Node::destruct

   return false;

 }

 // Identify all nodes that are reachable from below, useful.

 // Use breadth-first pass that records state in a Unique_Node_List,

 // recursive traversal is slower.

 void Compile::identify_useful_nodes(Unique_Node_List &useful) {

   int estimated_worklist_size = live_nodes();

   useful.map( estimated_worklist_size, NULL );  // preallocate space

   // Initialize worklist

   if (root() != NULL)     { useful.push(root()); }

   // If 'top' is cached, declare it useful to preserve cached node

   if( cached_top_node() ) { useful.push(cached_top_node()); }

   // Push all useful nodes onto the list, breadthfirst

   for( uint next = 0; next < useful.size(); ++next ) {

     assert( next < unique(), "Unique useful nodes < total nodes");

     Node *n  = useful.at(next);

     uint max = n->len();

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

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

       if (not_a_node(m))  continue;

       useful.push(m);

     }

   }

 }

 // Update dead_node_list with any missing dead nodes using useful

 // list. Consider all non-useful nodes to be useless i.e., dead nodes.

 void Compile::update_dead_node_list(Unique_Node_List &useful) {

   uint max_idx = unique();

   VectorSet& useful_node_set = useful.member_set();

   for (uint node_idx = 0; node_idx < max_idx; node_idx++) {

     // If node with index node_idx is not in useful set,

     // mark it as dead in dead node list.

     if (! useful_node_set.test(node_idx) ) {

       record_dead_node(node_idx);

     }

   }

 }

 void Compile::remove_useless_late_inlines(GrowableArray<CallGenerator*>* inlines, Unique_Node_List &useful) {

   int shift = 0;

   for (int i = 0; i < inlines->length(); i++) {

     CallGenerator* cg = inlines->at(i);

     CallNode* call = cg->call_node();

     if (shift > 0) {

       inlines->at_put(i-shift, cg);

     }

     if (!useful.member(call)) {

       shift++;

     }

   }

   inlines->trunc_to(inlines->length()-shift);

 }

 // Disconnect all useless nodes by disconnecting those at the boundary.

 void Compile::remove_useless_nodes(Unique_Node_List &useful) {

   uint next = 0;

   while (next < useful.size()) {

     Node *n = useful.at(next++);

     if (n->is_SafePoint()) {

       // We're done with a parsing phase. Replaced nodes are not valid

       // beyond that point.

       n->as_SafePoint()->delete_replaced_nodes();

     }

     // Use raw traversal of out edges since this code removes out edges

     int max = n->outcnt();

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

       Node* child = n->raw_out(j);

       if (! useful.member(child)) {

         assert(!child->is_top() || child != top(),

                "If top is cached in Compile object it is in useful list");

         // Only need to remove this out-edge to the useless node

         n->raw_del_out(j);

         --j;

         --max;

       }

     }

     if (n->outcnt() == 1 && n->has_special_unique_user()) {

       record_for_igvn(n->unique_out());

     }

   }

   // Remove useless macro and predicate opaq nodes

   for (int i = C->macro_count()-1; i >= 0; i--) {

     Node* n = C->macro_node(i);

     if (!useful.member(n)) {

       remove_macro_node(n);

     }

   }

   // Remove useless CastII nodes with range check dependency

   for (int i = range_check_cast_count() - 1; i >= 0; i--) {

     Node* cast = range_check_cast_node(i);

     if (!useful.member(cast)) {

       remove_range_check_cast(cast);

     }

   }

   // Remove useless expensive node

   for (int i = C->expensive_count()-1; i >= 0; i--) {

     Node* n = C->expensive_node(i);

     if (!useful.member(n)) {

       remove_expensive_node(n);

     }

   }

   // clean up the late inline lists

   remove_useless_late_inlines(&_string_late_inlines, useful);

   remove_useless_late_inlines(&_boxing_late_inlines, useful);

   remove_useless_late_inlines(&_late_inlines, useful);

   debug_only(verify_graph_edges(true/*check for no_dead_code*/);)

 }

 //------------------------------frame_size_in_words-----------------------------

 // frame_slots in units of words

 int Compile::frame_size_in_words() const {

   // shift is 0 in LP32 and 1 in LP64

   const int shift = (LogBytesPerWord - LogBytesPerInt);

   int words = _frame_slots >> shift;

   assert( words << shift == _frame_slots, "frame size must be properly aligned in LP64" );

   return words;

 }

 // To bang the stack of this compiled method we use the stack size

 // that the interpreter would need in case of a deoptimization. This

 // removes the need to bang the stack in the deoptimization blob which

 // in turn simplifies stack overflow handling.

 int Compile::bang_size_in_bytes() const {

   return MAX2(_interpreter_frame_size, frame_size_in_bytes());

 }

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

 //------------------------------CompileWrapper---------------------------------

 class CompileWrapper : public StackObj {

   Compile *const _compile;

  public:

   CompileWrapper(Compile* compile);

   ~CompileWrapper();

 };

 CompileWrapper::CompileWrapper(Compile* compile) : _compile(compile) {

   // the Compile* pointer is stored in the current ciEnv:

   ciEnv* env = compile->env();

   assert(env == ciEnv::current(), "must already be a ciEnv active");

   assert(env->compiler_data() == NULL, "compile already active?");

   env->set_compiler_data(compile);

   assert(compile == Compile::current(), "sanity");

   compile->set_type_dict(NULL);

   compile->set_type_hwm(NULL);

   compile->set_type_last_size(0);

   compile->set_last_tf(NULL, NULL);

   compile->set_indexSet_arena(NULL);

   compile->set_indexSet_free_block_list(NULL);

   compile->init_type_arena();

   Type::Initialize(compile);

   _compile->set_scratch_buffer_blob(NULL);

   _compile->begin_method();

 }

 CompileWrapper::~CompileWrapper() {

   _compile->end_method();

   if (_compile->scratch_buffer_blob() != NULL)

     BufferBlob::free(_compile->scratch_buffer_blob());

   _compile->env()->set_compiler_data(NULL);

 }

 //----------------------------print_compile_messages---------------------------

 void Compile::print_compile_messages() {

 #ifndef PRODUCT

   // Check if recompiling

   if (_subsume_loads == false && PrintOpto) {

     // Recompiling without allowing machine instructions to subsume loads

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

     tty->print_cr("** Bailout: Recompile without subsuming loads          **");

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

   }

   if (_do_escape_analysis != DoEscapeAnalysis && PrintOpto) {

     // Recompiling without escape analysis

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

     tty->print_cr("** Bailout: Recompile without escape analysis          **");

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

   }

   if (_eliminate_boxing != EliminateAutoBox && PrintOpto) {

     // Recompiling without boxing elimination

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

     tty->print_cr("** Bailout: Recompile without boxing elimination       **");

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

   }

   if (env()->break_at_compile()) {

     // Open the debugger when compiling this method.

     tty->print("### Breaking when compiling: ");

     method()->print_short_name();

     tty->cr();

     BREAKPOINT;

   }

   if( PrintOpto ) {

     if (is_osr_compilation()) {

       tty->print("[OSR]%3d", _compile_id);

     } else {

       tty->print("%3d", _compile_id);

     }

   }

 #endif

 }

 //-----------------------init_scratch_buffer_blob------------------------------

 // Construct a temporary BufferBlob and cache it for this compile.

 void Compile::init_scratch_buffer_blob(int const_size) {

   // If there is already a scratch buffer blob allocated and the

   // constant section is big enough, use it.  Otherwise free the

   // current and allocate a new one.

   BufferBlob* blob = scratch_buffer_blob();

   if ((blob != NULL) && (const_size <= _scratch_const_size)) {

     // Use the current blob.

   } else {

     if (blob != NULL) {

       BufferBlob::free(blob);

     }

     ResourceMark rm;

     _scratch_const_size = const_size;

     int size = (MAX_inst_size + MAX_stubs_size + _scratch_const_size);

     blob = BufferBlob::create("Compile::scratch_buffer", size);

     // Record the buffer blob for next time.

     set_scratch_buffer_blob(blob);

     // Have we run out of code space?

     if (scratch_buffer_blob() == NULL) {

       // Let CompilerBroker disable further compilations.

       record_failure("Not enough space for scratch buffer in CodeCache");

       return;

     }

   }

   // Initialize the relocation buffers

   relocInfo* locs_buf = (relocInfo*) blob->content_end() - MAX_locs_size;

   set_scratch_locs_memory(locs_buf);

 }

 //-----------------------scratch_emit_size-------------------------------------

 // Helper function that computes size by emitting code

 uint Compile::scratch_emit_size(const Node* n) {

   // Start scratch_emit_size section.

   set_in_scratch_emit_size(true);

   // Emit into a trash buffer and count bytes emitted.

   // This is a pretty expensive way to compute a size,

   // but it works well enough if seldom used.

   // All common fixed-size instructions are given a size

   // method by the AD file.

   // Note that the scratch buffer blob and locs memory are

   // allocated at the beginning of the compile task, and

   // may be shared by several calls to scratch_emit_size.

   // The allocation of the scratch buffer blob is particularly

   // expensive, since it has to grab the code cache lock.

   BufferBlob* blob = this->scratch_buffer_blob();

   assert(blob != NULL, "Initialize BufferBlob at start");

   assert(blob->size() > MAX_inst_size, "sanity");

   relocInfo* locs_buf = scratch_locs_memory();

   address blob_begin = blob->content_begin();

   address blob_end   = (address)locs_buf;

   assert(blob->content_contains(blob_end), "sanity");

   CodeBuffer buf(blob_begin, blob_end - blob_begin);

   buf.initialize_consts_size(_scratch_const_size);

   buf.initialize_stubs_size(MAX_stubs_size);

   assert(locs_buf != NULL, "sanity");

   int lsize = MAX_locs_size / 3;

   buf.consts()->initialize_shared_locs(&locs_buf[lsize * 0], lsize);

   buf.insts()->initialize_shared_locs( &locs_buf[lsize * 1], lsize);

   buf.stubs()->initialize_shared_locs( &locs_buf[lsize * 2], lsize);

   // Do the emission.

   Label fakeL; // Fake label for branch instructions.

   Label*   saveL = NULL;

   uint save_bnum = 0;

   bool is_branch = n->is_MachBranch();

   if (is_branch) {

     MacroAssembler masm(&buf);

     masm.bind(fakeL);

     n->as_MachBranch()->save_label(&saveL, &save_bnum);

     n->as_MachBranch()->label_set(&fakeL, 0);

   }

   n->emit(buf, this->regalloc());

   // Emitting into the scratch buffer should not fail

   assert (!failing(), err_msg_res("Must not have pending failure. Reason is: %s", failure_reason()));

   if (is_branch) // Restore label.

     n->as_MachBranch()->label_set(saveL, save_bnum);

   // End scratch_emit_size section.

   set_in_scratch_emit_size(false);

   return buf.insts_size();

 }

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

 //------------------------------Compile standard-------------------------------

 debug_only( int Compile::_debug_idx = 100000; )

 // Compile a method.  entry_bci is -1 for normal compilations and indicates

 // the continuation bci for on stack replacement.

 Compile::Compile( ciEnv* ci_env, C2Compiler* compiler, ciMethod* target, int osr_bci,

                   bool subsume_loads, bool do_escape_analysis, bool eliminate_boxing )

                 : Phase(Compiler),

                   _env(ci_env),

                   _log(ci_env->log()),

                   _compile_id(ci_env->compile_id()),

                   _save_argument_registers(false),

                   _stub_name(NULL),

                   _stub_function(NULL),

                   _stub_entry_point(NULL),

                   _method(target),

                   _entry_bci(osr_bci),

                   _initial_gvn(NULL),

                   _for_igvn(NULL),

                   _warm_calls(NULL),

                   _subsume_loads(subsume_loads),

                   _do_escape_analysis(do_escape_analysis),

                   _eliminate_boxing(eliminate_boxing),

                   _failure_reason(NULL),

                   _code_buffer("Compile::Fill_buffer"),

                   _orig_pc_slot(0),

                   _orig_pc_slot_offset_in_bytes(0),

                   _has_method_handle_invokes(false),

                   _mach_constant_base_node(NULL),

                   _node_bundling_limit(0),

                   _node_bundling_base(NULL),

                   _java_calls(0),

                   _inner_loops(0),

                   _scratch_const_size(-1),

                   _in_scratch_emit_size(false),

                   _dead_node_list(comp_arena()),

                   _dead_node_count(0),

 #ifndef PRODUCT

                   _trace_opto_output(TraceOptoOutput || method()->has_option("TraceOptoOutput")),

                   _in_dump_cnt(0),

                   _printer(IdealGraphPrinter::printer()),

 #endif

                   _congraph(NULL),

                   _comp_arena(mtCompiler),

                   _node_arena(mtCompiler),

                   _old_arena(mtCompiler),

                   _Compile_types(mtCompiler),

                   _replay_inline_data(NULL),

                   _late_inlines(comp_arena(), 2, 0, NULL),

                   _string_late_inlines(comp_arena(), 2, 0, NULL),

                   _boxing_late_inlines(comp_arena(), 2, 0, NULL),

                   _late_inlines_pos(0),

                   _number_of_mh_late_inlines(0),

                   _inlining_progress(false),

                   _inlining_incrementally(false),

                   _print_inlining_list(NULL),

                   _print_inlining_idx(0),

                   _interpreter_frame_size(0),

                   _max_node_limit(MaxNodeLimit) {

   C = this;

   CompileWrapper cw(this);

 #ifndef PRODUCT

   if (TimeCompiler2) {

     tty->print(" ");

     target->holder()->name()->print();

     tty->print(".");

     target->print_short_name();

     tty->print("  ");

   }

   TraceTime t1("Total compilation time", &_t_totalCompilation, TimeCompiler, TimeCompiler2);

   TraceTime t2(NULL, &_t_methodCompilation, TimeCompiler, false);

   bool print_opto_assembly = PrintOptoAssembly || _method->has_option("PrintOptoAssembly");

   if (!print_opto_assembly) {

     bool print_assembly = (PrintAssembly || _method->should_print_assembly());

     if (print_assembly && !Disassembler::can_decode()) {

       tty->print_cr("PrintAssembly request changed to PrintOptoAssembly");

       print_opto_assembly = true;

     }

   }

   set_print_assembly(print_opto_assembly);

   set_parsed_irreducible_loop(false);

   if (method()->has_option("ReplayInline")) {

     _replay_inline_data = ciReplay::load_inline_data(method(), entry_bci(), ci_env->comp_level());

   }

 #endif

   set_print_inlining(PrintInlining || method()->has_option("PrintInlining") NOT_PRODUCT( || PrintOptoInlining));

   set_print_intrinsics(PrintIntrinsics || method()->has_option("PrintIntrinsics"));

   set_has_irreducible_loop(true); // conservative until build_loop_tree() reset it

   if (ProfileTraps RTM_OPT_ONLY( || UseRTMLocking )) {

     // Make sure the method being compiled gets its own MDO,

     // so we can at least track the decompile_count().

     // Need MDO to record RTM code generation state.

     method()->ensure_method_data();

   }

   Init(::AliasLevel);

   print_compile_messages();

   _ilt = InlineTree::build_inline_tree_root();

   // Even if NO memory addresses are used, MergeMem nodes must have at least 1 slice

   assert(num_alias_types() >= AliasIdxRaw, "");

 #define MINIMUM_NODE_HASH  1023

   // Node list that Iterative GVN will start with

   Unique_Node_List for_igvn(comp_arena());

   set_for_igvn(&for_igvn);

   // GVN that will be run immediately on new nodes

   uint estimated_size = method()->code_size()*4+64;

   estimated_size = (estimated_size < MINIMUM_NODE_HASH ? MINIMUM_NODE_HASH : estimated_size);

   PhaseGVN gvn(node_arena(), estimated_size);

   set_initial_gvn(&gvn);

   if (print_inlining() || print_intrinsics()) {

     _print_inlining_list = new (comp_arena())GrowableArray<PrintInliningBuffer>(comp_arena(), 1, 1, PrintInliningBuffer());

   }

   { // Scope for timing the parser

     TracePhase t3("parse", &_t_parser, true);

     // Put top into the hash table ASAP.

     initial_gvn()->transform_no_reclaim(top());

     // Set up tf(), start(), and find a CallGenerator.

     CallGenerator* cg = NULL;

     if (is_osr_compilation()) {

       const TypeTuple *domain = StartOSRNode::osr_domain();

       const TypeTuple *range = TypeTuple::make_range(method()->signature());

       init_tf(TypeFunc::make(domain, range));

       StartNode* s = new (this) StartOSRNode(root(), domain);

       initial_gvn()->set_type_bottom(s);

       init_start(s);

       cg = CallGenerator::for_osr(method(), entry_bci());

     } else {

       // Normal case.

       init_tf(TypeFunc::make(method()));

       StartNode* s = new (this) StartNode(root(), tf()->domain());

       initial_gvn()->set_type_bottom(s);

       init_start(s);

       if (method()->intrinsic_id() == vmIntrinsics::_Reference_get && UseG1GC) {

         // With java.lang.ref.reference.get() we must go through the

         // intrinsic when G1 is enabled - even when get() is the root

         // method of the compile - so that, if necessary, the value in

         // the referent field of the reference object gets recorded by

         // the pre-barrier code.

         // Specifically, if G1 is enabled, the value in the referent

         // field is recorded by the G1 SATB pre barrier. This will

         // result in the referent being marked live and the reference

         // object removed from the list of discovered references during

         // reference processing.

         cg = find_intrinsic(method(), false);

       }

       if (cg == NULL) {

         float past_uses = method()->interpreter_invocation_count();

         float expected_uses = past_uses;

         cg = CallGenerator::for_inline(method(), expected_uses);

       }

     }

     if (failing())  return;

     if (cg == NULL) {

       record_method_not_compilable_all_tiers("cannot parse method");

       return;

     }

     JVMState* jvms = build_start_state(start(), tf());

     if ((jvms = cg->generate(jvms)) == NULL) {

       if (!failure_reason_is(C2Compiler::retry_class_loading_during_parsing())) {

         record_method_not_compilable("method parse failed");

       }

       return;

     }

     GraphKit kit(jvms);

     if (!kit.stopped()) {

       // Accept return values, and transfer control we know not where.

       // This is done by a special, unique ReturnNode bound to root.

       return_values(kit.jvms());

     }

     if (kit.has_exceptions()) {

       // Any exceptions that escape from this call must be rethrown

       // to whatever caller is dynamically above us on the stack.

       // This is done by a special, unique RethrowNode bound to root.

       rethrow_exceptions(kit.transfer_exceptions_into_jvms());

     }

     assert(IncrementalInline || (_late_inlines.length() == 0 && !has_mh_late_inlines()), "incremental inlining is off");

     if (_late_inlines.length() == 0 && !has_mh_late_inlines() && !failing() && has_stringbuilder()) {

       inline_string_calls(true);

     }

     if (failing())  return;

     print_method(PHASE_BEFORE_REMOVEUSELESS, 3);

     // Remove clutter produced by parsing.

     if (!failing()) {

       ResourceMark rm;

       PhaseRemoveUseless pru(initial_gvn(), &for_igvn);

     }

   }

   // Note:  Large methods are capped off in do_one_bytecode().

   if (failing())  return;

   // After parsing, node notes are no longer automagic.

   // They must be propagated by register_new_node_with_optimizer(),

   // clone(), or the like.

   set_default_node_notes(NULL);

   for (;;) {

     int successes = Inline_Warm();

     if (failing())  return;

     if (successes == 0)  break;

   }

   // Drain the list.

   Finish_Warm();

 #ifndef PRODUCT

   if (_printer) {

     _printer->print_inlining(this);

   }

 #endif

   if (failing())  return;

   NOT_PRODUCT( verify_graph_edges(); )

   // Now optimize

   Optimize();

   if (failing())  return;

   NOT_PRODUCT( verify_graph_edges(); )

 #ifndef PRODUCT

   if (PrintIdeal) {

     ttyLocker ttyl;  // keep the following output all in one block

     // This output goes directly to the tty, not the compiler log.

     // To enable tools to match it up with the compilation activity,

     // be sure to tag this tty output with the compile ID.

     if (xtty != NULL) {

       xtty->head("ideal compile_id='%d'%s", compile_id(),

                  is_osr_compilation()    ? " compile_kind='osr'" :

                  "");

     }

     root()->dump(9999);

     if (xtty != NULL) {

       xtty->tail("ideal");

     }

   }

 #endif

   NOT_PRODUCT( verify_barriers(); )

   // Dump compilation data to replay it.

   if (method()->has_option("DumpReplay")) {

     env()->dump_replay_data(_compile_id);

   }

   if (method()->has_option("DumpInline") && (ilt() != NULL)) {

     env()->dump_inline_data(_compile_id);

   }

   // Now that we know the size of all the monitors we can add a fixed slot

   // for the original deopt pc.

   _orig_pc_slot =  fixed_slots();

   int next_slot = _orig_pc_slot + (sizeof(address) / VMRegImpl::stack_slot_size);

   set_fixed_slots(next_slot);

   // Compute when to use implicit null checks. Used by matching trap based

   // nodes and NullCheck optimization.

   set_allowed_deopt_reasons();

   // Now generate code

   Code_Gen();

   if (failing())  return;

   // Check if we want to skip execution of all compiled code.

   {

 #ifndef PRODUCT

     if (OptoNoExecute) {

       record_method_not_compilable("+OptoNoExecute");  // Flag as failed

       return;

     }

     TracePhase t2("install_code", &_t_registerMethod, TimeCompiler);

 #endif

     if (is_osr_compilation()) {

       _code_offsets.set_value(CodeOffsets::Verified_Entry, 0);

       _code_offsets.set_value(CodeOffsets::OSR_Entry, _first_block_size);

     } else {

       _code_offsets.set_value(CodeOffsets::Verified_Entry, _first_block_size);

       _code_offsets.set_value(CodeOffsets::OSR_Entry, 0);

     }

     env()->register_method(_method, _entry_bci,

                            &_code_offsets,

                            _orig_pc_slot_offset_in_bytes,

                            code_buffer(),

                            frame_size_in_words(), _oop_map_set,

                            &_handler_table, &_inc_table,

                            compiler,

                            env()->comp_level(),

                            has_unsafe_access(),

                            SharedRuntime::is_wide_vector(max_vector_size()),

                            rtm_state()

                            );

     if (log() != NULL) // Print code cache state into compiler log

       log()->code_cache_state();

   }

 }

 //------------------------------Compile----------------------------------------

 // Compile a runtime stub

 Compile::Compile( ciEnv* ci_env,

                   TypeFunc_generator generator,

                   address stub_function,

                   const char *stub_name,

                   int is_fancy_jump,

                   bool pass_tls,

                   bool save_arg_registers,

                   bool return_pc )

   : Phase(Compiler),

     _env(ci_env),

     _log(ci_env->log()),

     _compile_id(0),

     _save_argument_registers(save_arg_registers),

     _method(NULL),

     _stub_name(stub_name),

     _stub_function(stub_function),

     _stub_entry_point(NULL),

     _entry_bci(InvocationEntryBci),

     _initial_gvn(NULL),

     _for_igvn(NULL),

     _warm_calls(NULL),

     _orig_pc_slot(0),

     _orig_pc_slot_offset_in_bytes(0),

     _subsume_loads(true),

     _do_escape_analysis(false),

     _eliminate_boxing(false),

     _failure_reason(NULL),

     _code_buffer("Compile::Fill_buffer"),

     _has_method_handle_invokes(false),

     _mach_constant_base_node(NULL),

     _node_bundling_limit(0),

     _node_bundling_base(NULL),

     _java_calls(0),

     _inner_loops(0),

 #ifndef PRODUCT

     _trace_opto_output(TraceOptoOutput),

     _in_dump_cnt(0),

     _printer(NULL),

 #endif

     _comp_arena(mtCompiler),

     _node_arena(mtCompiler),

     _old_arena(mtCompiler),

     _Compile_types(mtCompiler),

     _dead_node_list(comp_arena()),

     _dead_node_count(0),

     _congraph(NULL),

     _replay_inline_data(NULL),

     _number_of_mh_late_inlines(0),

     _inlining_progress(false),

     _inlining_incrementally(false),

     _print_inlining_list(NULL),

     _print_inlining_idx(0),

     _allowed_reasons(0),

     _interpreter_frame_size(0),

     _max_node_limit(MaxNodeLimit) {

   C = this;

 #ifndef PRODUCT

   TraceTime t1(NULL, &_t_totalCompilation, TimeCompiler, false);

   TraceTime t2(NULL, &_t_stubCompilation, TimeCompiler, false);

   set_print_assembly(PrintFrameConverterAssembly);

   set_parsed_irreducible_loop(false);

 #endif

   set_has_irreducible_loop(false); // no loops

   CompileWrapper cw(this);

   Init(/*AliasLevel=*/ 0);

   init_tf((*generator)());

   {

     // The following is a dummy for the sake of GraphKit::gen_stub

     Unique_Node_List for_igvn(comp_arena());

     set_for_igvn(&for_igvn);  // not used, but some GraphKit guys push on this

     PhaseGVN gvn(Thread::current()->resource_area(),255);

     set_initial_gvn(&gvn);    // not significant, but GraphKit guys use it pervasively

     gvn.transform_no_reclaim(top());

     GraphKit kit;

     kit.gen_stub(stub_function, stub_name, is_fancy_jump, pass_tls, return_pc);

   }

   NOT_PRODUCT( verify_graph_edges(); )

   Code_Gen();

   if (failing())  return;

   // Entry point will be accessed using compile->stub_entry_point();

   if (code_buffer() == NULL) {

     Matcher::soft_match_failure();

   } else {

     if (PrintAssembly && (WizardMode || Verbose))

       tty->print_cr("### Stub::%s", stub_name);

     if (!failing()) {

       assert(_fixed_slots == 0, "no fixed slots used for runtime stubs");

       // Make the NMethod

       // For now we mark the frame as never safe for profile stackwalking

       RuntimeStub *rs = RuntimeStub::new_runtime_stub(stub_name,

                                                       code_buffer(),

                                                       CodeOffsets::frame_never_safe,

                                                       // _code_offsets.value(CodeOffsets::Frame_Complete),

                                                       frame_size_in_words(),

                                                       _oop_map_set,

                                                       save_arg_registers);

       assert(rs != NULL && rs->is_runtime_stub(), "sanity check");

       _stub_entry_point = rs->entry_point();

     }

   }

 }

 //------------------------------Init-------------------------------------------

 // Prepare for a single compilation

 void Compile::Init(int aliaslevel) {

   _unique  = 0;

   _regalloc = NULL;

   _tf      = NULL;  // filled in later

   _top     = NULL;  // cached later

   _matcher = NULL;  // filled in later

   _cfg     = NULL;  // filled in later

   set_24_bit_selection_and_mode(Use24BitFP, false);

   _node_note_array = NULL;

   _default_node_notes = NULL;

   _immutable_memory = NULL; // filled in at first inquiry

   // Globally visible Nodes

   // First set TOP to NULL to give safe behavior during creation of RootNode

   set_cached_top_node(NULL);

   set_root(new (this) RootNode());

   // Now that you have a Root to point to, create the real TOP

   set_cached_top_node( new (this) ConNode(Type::TOP) );

   set_recent_alloc(NULL, NULL);

   // Create Debug Information Recorder to record scopes, oopmaps, etc.

   env()->set_oop_recorder(new OopRecorder(env()->arena()));

   env()->set_debug_info(new DebugInformationRecorder(env()->oop_recorder()));

   env()->set_dependencies(new Dependencies(env()));

   _fixed_slots = 0;

   set_has_split_ifs(false);

   set_has_loops(has_method() && method()->has_loops()); // first approximation

   set_has_stringbuilder(false);

   set_has_boxed_value(false);

   _trap_can_recompile = false;  // no traps emitted yet

   _major_progress = true; // start out assuming good things will happen

   set_has_unsafe_access(false);

   set_max_vector_size(0);

   Copy::zero_to_bytes(_trap_hist, sizeof(_trap_hist));

   set_decompile_count(0);

   set_do_freq_based_layout(BlockLayoutByFrequency || method_has_option("BlockLayoutByFrequency"));

   set_num_loop_opts(LoopOptsCount);

   set_do_inlining(Inline);

   set_max_inline_size(MaxInlineSize);

   set_freq_inline_size(FreqInlineSize);

   set_do_scheduling(OptoScheduling);

   set_do_count_invocations(false);

   set_do_method_data_update(false);

   set_rtm_state(NoRTM); // No RTM lock eliding by default

   method_has_option_value("MaxNodeLimit", _max_node_limit);

 #if INCLUDE_RTM_OPT

   if (UseRTMLocking && has_method() && (method()->method_data_or_null() != NULL)) {

     int rtm_state = method()->method_data()->rtm_state();

     if (method_has_option("NoRTMLockEliding") || ((rtm_state & NoRTM) != 0)) {

       // Don't generate RTM lock eliding code.

       set_rtm_state(NoRTM);

     } else if (method_has_option("UseRTMLockEliding") || ((rtm_state & UseRTM) != 0) || !UseRTMDeopt) {

       // Generate RTM lock eliding code without abort ratio calculation code.

       set_rtm_state(UseRTM);

     } else if (UseRTMDeopt) {

       // Generate RTM lock eliding code and include abort ratio calculation

       // code if UseRTMDeopt is on.

       set_rtm_state(ProfileRTM);

     }

   }

 #endif

   if (debug_info()->recording_non_safepoints()) {

     set_node_note_array(new(comp_arena()) GrowableArray<Node_Notes*>

                         (comp_arena(), 8, 0, NULL));

     set_default_node_notes(Node_Notes::make(this));

   }

   // // -- Initialize types before each compile --

   // // Update cached type information

   // if( _method && _method->constants() )

   //   Type::update_loaded_types(_method, _method->constants());

   // Init alias_type map.

   if (!_do_escape_analysis && aliaslevel == 3)

     aliaslevel = 2;  // No unique types without escape analysis

   _AliasLevel = aliaslevel;

   const int grow_ats = 16;

   _max_alias_types = grow_ats;

   _alias_types   = NEW_ARENA_ARRAY(comp_arena(), AliasType*, grow_ats);

   AliasType* ats = NEW_ARENA_ARRAY(comp_arena(), AliasType,  grow_ats);

   Copy::zero_to_bytes(ats, sizeof(AliasType)*grow_ats);

   {

     for (int i = 0; i < grow_ats; i++)  _alias_types[i] = &ats[i];

   }

   // Initialize the first few types.

   _alias_types[AliasIdxTop]->Init(AliasIdxTop, NULL);

   _alias_types[AliasIdxBot]->Init(AliasIdxBot, TypePtr::BOTTOM);

   _alias_types[AliasIdxRaw]->Init(AliasIdxRaw, TypeRawPtr::BOTTOM);

   _num_alias_types = AliasIdxRaw+1;

   // Zero out the alias type cache.

   Copy::zero_to_bytes(_alias_cache, sizeof(_alias_cache));

   // A NULL adr_type hits in the cache right away.  Preload the right answer.

   probe_alias_cache(NULL)->_index = AliasIdxTop;

   _intrinsics = NULL;

   _macro_nodes = new(comp_arena()) GrowableArray<Node*>(comp_arena(), 8,  0, NULL);

   _predicate_opaqs = new(comp_arena()) GrowableArray<Node*>(comp_arena(), 8,  0, NULL);

   _expensive_nodes = new(comp_arena()) GrowableArray<Node*>(comp_arena(), 8,  0, NULL);

   _range_check_casts = new(comp_arena()) GrowableArray<Node*>(comp_arena(), 8,  0, NULL);

   register_library_intrinsics();

 #ifdef ASSERT

   _type_verify_symmetry = true;

 #endif

 }

 //---------------------------init_start----------------------------------------

 // Install the StartNode on this compile object.

 void Compile::init_start(StartNode* s) {

   if (failing())

     return; // already failing

   assert(s == start(), "");

 }

 StartNode* Compile::start() const {

   assert(!failing(), "");

   for (DUIterator_Fast imax, i = root()->fast_outs(imax); i < imax; i++) {

     Node* start = root()->fast_out(i);

     if( start->is_Start() )

       return start->as_Start();

   }

   fatal("Did not find Start node!");

   return NULL;

 }

 //-------------------------------immutable_memory-------------------------------------

 // Access immutable memory

 Node* Compile::immutable_memory() {

   if (_immutable_memory != NULL) {

     return _immutable_memory;

   }

   StartNode* s = start();

   for (DUIterator_Fast imax, i = s->fast_outs(imax); true; i++) {

     Node *p = s->fast_out(i);

     if (p != s && p->as_Proj()->_con == TypeFunc::Memory) {

       _immutable_memory = p;

       return _immutable_memory;

     }

   }

   ShouldNotReachHere();

   return NULL;

 }

 //----------------------set_cached_top_node------------------------------------

 // Install the cached top node, and make sure Node::is_top works correctly.

 void Compile::set_cached_top_node(Node* tn) {

   if (tn != NULL)  verify_top(tn);

   Node* old_top = _top;

   _top = tn;

   // Calling Node::setup_is_top allows the nodes the chance to adjust

   // their _out arrays.

   if (_top != NULL)     _top->setup_is_top();

   if (old_top != NULL)  old_top->setup_is_top();

   assert(_top == NULL || top()->is_top(), "");

 }

 #ifdef ASSERT

 uint Compile::count_live_nodes_by_graph_walk() {

   Unique_Node_List useful(comp_arena());

   // Get useful node list by walking the graph.

   identify_useful_nodes(useful);

   return useful.size();

 }

 void Compile::print_missing_nodes() {

   // Return if CompileLog is NULL and PrintIdealNodeCount is false.

   if ((_log == NULL) && (! PrintIdealNodeCount)) {

     return;

   }

   // This is an expensive function. It is executed only when the user

   // specifies VerifyIdealNodeCount option or otherwise knows the

   // additional work that needs to be done to identify reachable nodes

   // by walking the flow graph and find the missing ones using

   // _dead_node_list.

   Unique_Node_List useful(comp_arena());

   // Get useful node list by walking the graph.

   identify_useful_nodes(useful);

   uint l_nodes = C->live_nodes();

   uint l_nodes_by_walk = useful.size();

   if (l_nodes != l_nodes_by_walk) {

     if (_log != NULL) {

       _log->begin_head("mismatched_nodes count='%d'", abs((int) (l_nodes - l_nodes_by_walk)));

       _log->stamp();

       _log->end_head();

     }

     VectorSet& useful_member_set = useful.member_set();

     int last_idx = l_nodes_by_walk;

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

       if (useful_member_set.test(i)) {

         if (_dead_node_list.test(i)) {

           if (_log != NULL) {

             _log->elem("mismatched_node_info node_idx='%d' type='both live and dead'", i);

           }

           if (PrintIdealNodeCount) {

             // Print the log message to tty

               tty->print_cr("mismatched_node idx='%d' both live and dead'", i);

               useful.at(i)->dump();

           }

         }

       }

       else if (! _dead_node_list.test(i)) {

         if (_log != NULL) {

           _log->elem("mismatched_node_info node_idx='%d' type='neither live nor dead'", i);

         }

         if (PrintIdealNodeCount) {

           // Print the log message to tty

           tty->print_cr("mismatched_node idx='%d' type='neither live nor dead'", i);

         }

       }

     }

     if (_log != NULL) {

       _log->tail("mismatched_nodes");

     }

   }

 }

 #endif

 #ifndef PRODUCT

 void Compile::verify_top(Node* tn) const {

   if (tn != NULL) {

     assert(tn->is_Con(), "top node must be a constant");

     assert(((ConNode*)tn)->type() == Type::TOP, "top node must have correct type");

     assert(tn->in(0) != NULL, "must have live top node");

   }

 }

 #endif

 ///-------------------Managing Per-Node Debug & Profile Info-------------------

 void Compile::grow_node_notes(GrowableArray<Node_Notes*>* arr, int grow_by) {

   guarantee(arr != NULL, "");

   int num_blocks = arr->length();

   if (grow_by < num_blocks)  grow_by = num_blocks;

   int num_notes = grow_by * _node_notes_block_size;

   Node_Notes* notes = NEW_ARENA_ARRAY(node_arena(), Node_Notes, num_notes);

   Copy::zero_to_bytes(notes, num_notes * sizeof(Node_Notes));

   while (num_notes > 0) {

     arr->append(notes);

     notes     += _node_notes_block_size;

     num_notes -= _node_notes_block_size;

   }

   assert(num_notes == 0, "exact multiple, please");

 }

 bool Compile::copy_node_notes_to(Node* dest, Node* source) {

   if (source == NULL || dest == NULL)  return false;

   if (dest->is_Con())

     return false;               // Do not push debug info onto constants.

 #ifdef ASSERT

   // Leave a bread crumb trail pointing to the original node:

   if (dest != NULL && dest != source && dest->debug_orig() == NULL) {

     dest->set_debug_orig(source);

   }

 #endif

   if (node_note_array() == NULL)

     return false;               // Not collecting any notes now.

   // This is a copy onto a pre-existing node, which may already have notes.

   // If both nodes have notes, do not overwrite any pre-existing notes.

   Node_Notes* source_notes = node_notes_at(source->_idx);

   if (source_notes == NULL || source_notes->is_clear())  return false;

   Node_Notes* dest_notes   = node_notes_at(dest->_idx);

   if (dest_notes == NULL || dest_notes->is_clear()) {

     return set_node_notes_at(dest->_idx, source_notes);

   }

   Node_Notes merged_notes = (*source_notes);

   // The order of operations here ensures that dest notes will win...

   merged_notes.update_from(dest_notes);

   return set_node_notes_at(dest->_idx, &merged_notes);

 }

 //--------------------------allow_range_check_smearing-------------------------

 // Gating condition for coalescing similar range checks.

 // Sometimes we try 'speculatively' replacing a series of a range checks by a

 // single covering check that is at least as strong as any of them.

 // If the optimization succeeds, the simplified (strengthened) range check

 // will always succeed.  If it fails, we will deopt, and then give up

 // on the optimization.

 bool Compile::allow_range_check_smearing() const {

   // If this method has already thrown a range-check,

   // assume it was because we already tried range smearing

   // and it failed.

   uint already_trapped = trap_count(Deoptimization::Reason_range_check);

   return !already_trapped;

 }

 //------------------------------flatten_alias_type-----------------------------

 const TypePtr *Compile::flatten_alias_type( const TypePtr *tj ) const {

   int offset = tj->offset();

   TypePtr::PTR ptr = tj->ptr();

   // Known instance (scalarizable allocation) alias only with itself.

   bool is_known_inst = tj->isa_oopptr() != NULL &&

                        tj->is_oopptr()->is_known_instance();

   // Process weird unsafe references.

   if (offset == Type::OffsetBot && (tj->isa_instptr() /*|| tj->isa_klassptr()*/)) {

     assert(InlineUnsafeOps, "indeterminate pointers come only from unsafe ops");

     assert(!is_known_inst, "scalarizable allocation should not have unsafe references");

     tj = TypeOopPtr::BOTTOM;

     ptr = tj->ptr();

     offset = tj->offset();

   }

   // Array pointers need some flattening

   const TypeAryPtr *ta = tj->isa_aryptr();

   if (ta && ta->is_stable()) {

     // Erase stability property for alias analysis.

     tj = ta = ta->cast_to_stable(false);

   }

   if( ta && is_known_inst ) {

     if ( offset != Type::OffsetBot &&

          offset > arrayOopDesc::length_offset_in_bytes() ) {

       offset = Type::OffsetBot; // Flatten constant access into array body only

       tj = ta = TypeAryPtr::make(ptr, ta->ary(), ta->klass(), true, offset, ta->instance_id());

     }

   } else if( ta && _AliasLevel >= 2 ) {

     // For arrays indexed by constant indices, we flatten the alias

     // space to include all of the array body.  Only the header, klass

     // and array length can be accessed un-aliased.

     if( offset != Type::OffsetBot ) {

       if( ta->const_oop() ) { // MethodData* or Method*

         offset = Type::OffsetBot;   // Flatten constant access into array body

         tj = ta = TypeAryPtr::make(ptr,ta->const_oop(),ta->ary(),ta->klass(),false,offset);

       } else if( offset == arrayOopDesc::length_offset_in_bytes() ) {

         // range is OK as-is.

         tj = ta = TypeAryPtr::RANGE;

       } else if( offset == oopDesc::klass_offset_in_bytes() ) {

         tj = TypeInstPtr::KLASS; // all klass loads look alike

         ta = TypeAryPtr::RANGE; // generic ignored junk

         ptr = TypePtr::BotPTR;

       } else if( offset == oopDesc::mark_offset_in_bytes() ) {

         tj = TypeInstPtr::MARK;

         ta = TypeAryPtr::RANGE; // generic ignored junk

         ptr = TypePtr::BotPTR;

       } else {                  // Random constant offset into array body

         offset = Type::OffsetBot;   // Flatten constant access into array body

         tj = ta = TypeAryPtr::make(ptr,ta->ary(),ta->klass(),false,offset);

       }

     }

     // Arrays of fixed size alias with arrays of unknown size.

     if (ta->size() != TypeInt::POS) {

       const TypeAry *tary = TypeAry::make(ta->elem(), TypeInt::POS);

       tj = ta = TypeAryPtr::make(ptr,ta->const_oop(),tary,ta->klass(),false,offset);

     }

     // Arrays of known objects become arrays of unknown objects.

     if (ta->elem()->isa_narrowoop() && ta->elem() != TypeNarrowOop::BOTTOM) {

       const TypeAry *tary = TypeAry::make(TypeNarrowOop::BOTTOM, ta->size());

       tj = ta = TypeAryPtr::make(ptr,ta->const_oop(),tary,NULL,false,offset);

     }

     if (ta->elem()->isa_oopptr() && ta->elem() != TypeInstPtr::BOTTOM) {

       const TypeAry *tary = TypeAry::make(TypeInstPtr::BOTTOM, ta->size());

       tj = ta = TypeAryPtr::make(ptr,ta->const_oop(),tary,NULL,false,offset);

     }

     // Arrays of bytes and of booleans both use 'bastore' and 'baload' so

     // cannot be distinguished by bytecode alone.

     if (ta->elem() == TypeInt::BOOL) {

       const TypeAry *tary = TypeAry::make(TypeInt::BYTE, ta->size());

       ciKlass* aklass = ciTypeArrayKlass::make(T_BYTE);

       tj = ta = TypeAryPtr::make(ptr,ta->const_oop(),tary,aklass,false,offset);

     }

     // During the 2nd round of IterGVN, NotNull castings are removed.

     // Make sure the Bottom and NotNull variants alias the same.

     // Also, make sure exact and non-exact variants alias the same.

     if (ptr == TypePtr::NotNull || ta->klass_is_exact() || ta->speculative() != NULL) {

       tj = ta = TypeAryPtr::make(TypePtr::BotPTR,ta->ary(),ta->klass(),false,offset);

     }

   }

   // Oop pointers need some flattening

   const TypeInstPtr *to = tj->isa_instptr();

   if( to && _AliasLevel >= 2 && to != TypeOopPtr::BOTTOM ) {

     ciInstanceKlass *k = to->klass()->as_instance_klass();

     if( ptr == TypePtr::Constant ) {

       if (to->klass() != ciEnv::current()->Class_klass() ||

           offset < k->size_helper() * wordSize) {

         // No constant oop pointers (such as Strings); they alias with

         // unknown strings.

         assert(!is_known_inst, "not scalarizable allocation");

         tj = to = TypeInstPtr::make(TypePtr::BotPTR,to->klass(),false,0,offset);

       }

     } else if( is_known_inst ) {

       tj = to; // Keep NotNull and klass_is_exact for instance type

     } else if( ptr == TypePtr::NotNull || to->klass_is_exact() ) {

       // During the 2nd round of IterGVN, NotNull castings are removed.

       // Make sure the Bottom and NotNull variants alias the same.

       // Also, make sure exact and non-exact variants alias the same.

       tj = to = TypeInstPtr::make(TypePtr::BotPTR,to->klass(),false,0,offset);

     }

     if (to->speculative() != NULL) {

       tj = to = TypeInstPtr::make(to->ptr(),to->klass(),to->klass_is_exact(),to->const_oop(),to->offset(), to->instance_id());

     }

     // Canonicalize the holder of this field

     if (offset >= 0 && offset < instanceOopDesc::base_offset_in_bytes()) {

       // First handle header references such as a LoadKlassNode, even if the

       // object's klass is unloaded at compile time (4965979).

       if (!is_known_inst) { // Do it only for non-instance types

         tj = to = TypeInstPtr::make(TypePtr::BotPTR, env()->Object_klass(), false, NULL, offset);

       }

     } else if (offset < 0 || offset >= k->size_helper() * wordSize) {

       // Static fields are in the space above the normal instance

       // fields in the java.lang.Class instance.

       if (to->klass() != ciEnv::current()->Class_klass()) {

         to = NULL;

         tj = TypeOopPtr::BOTTOM;

         offset = tj->offset();

       }

     } else {

       ciInstanceKlass *canonical_holder = k->get_canonical_holder(offset);

       if (!k->equals(canonical_holder) || tj->offset() != offset) {

         if( is_known_inst ) {

           tj = to = TypeInstPtr::make(to->ptr(), canonical_holder, true, NULL, offset, to->instance_id());

         } else {

           tj = to = TypeInstPtr::make(to->ptr(), canonical_holder, false, NULL, offset);

         }

       }

     }

   }

   // Klass pointers to object array klasses need some flattening

   const TypeKlassPtr *tk = tj->isa_klassptr();

   if( tk ) {

     // If we are referencing a field within a Klass, we need

     // to assume the worst case of an Object.  Both exact and

     // inexact types must flatten to the same alias class so

     // use NotNull as the PTR.

     if ( offset == Type::OffsetBot || (offset >= 0 && (size_t)offset < sizeof(Klass)) ) {

       tj = tk = TypeKlassPtr::make(TypePtr::NotNull,

                                    TypeKlassPtr::OBJECT->klass(),

                                    offset);

     }

     ciKlass* klass = tk->klass();

     if( klass->is_obj_array_klass() ) {

       ciKlass* k = TypeAryPtr::OOPS->klass();

       if( !k || !k->is_loaded() )                  // Only fails for some -Xcomp runs

         k = TypeInstPtr::BOTTOM->klass();

       tj = tk = TypeKlassPtr::make( TypePtr::NotNull, k, offset );

     }

     // Check for precise loads from the primary supertype array and force them

     // to the supertype cache alias index.  Check for generic array loads from

     // the primary supertype array and also force them to the supertype cache

     // alias index.  Since the same load can reach both, we need to merge

     // these 2 disparate memories into the same alias class.  Since the

     // primary supertype array is read-only, there's no chance of confusion

     // where we bypass an array load and an array store.

     int primary_supers_offset = in_bytes(Klass::primary_supers_offset());

     if (offset == Type::OffsetBot ||

         (offset >= primary_supers_offset &&

          offset < (int)(primary_supers_offset + Klass::primary_super_limit() * wordSize)) ||

         offset == (int)in_bytes(Klass::secondary_super_cache_offset())) {

       offset = in_bytes(Klass::secondary_super_cache_offset());

       tj = tk = TypeKlassPtr::make( TypePtr::NotNull, tk->klass(), offset );

     }

   }

   // Flatten all Raw pointers together.

   if (tj->base() == Type::RawPtr)

     tj = TypeRawPtr::BOTTOM;

   if (tj->base() == Type::AnyPtr)

     tj = TypePtr::BOTTOM;      // An error, which the caller must check for.

   // Flatten all to bottom for now

   switch( _AliasLevel ) {

   case 0:

     tj = TypePtr::BOTTOM;

     break;

   case 1:                       // Flatten to: oop, static, field or array

     switch (tj->base()) {

     //case Type::AryPtr: tj = TypeAryPtr::RANGE;    break;

     case Type::RawPtr:   tj = TypeRawPtr::BOTTOM;   break;

     case Type::AryPtr:   // do not distinguish arrays at all

     case Type::InstPtr:  tj = TypeInstPtr::BOTTOM;  break;

     case Type::KlassPtr: tj = TypeKlassPtr::OBJECT; break;

     case Type::AnyPtr:   tj = TypePtr::BOTTOM;      break;  // caller checks it

     default: ShouldNotReachHere();

     }

     break;

   case 2:                       // No collapsing at level 2; keep all splits

   case 3:                       // No collapsing at level 3; keep all splits

     break;

   default:

     Unimplemented();

   }

   offset = tj->offset();

   assert( offset != Type::OffsetTop, "Offset has fallen from constant" );

   assert( (offset != Type::OffsetBot && tj->base() != Type::AryPtr) ||

           (offset == Type::OffsetBot && tj->base() == Type::AryPtr) ||

           (offset == Type::OffsetBot && tj == TypeOopPtr::BOTTOM) ||

           (offset == Type::OffsetBot && tj == TypePtr::BOTTOM) ||

           (offset == oopDesc::mark_offset_in_bytes() && tj->base() == Type::AryPtr) ||

           (offset == oopDesc::klass_offset_in_bytes() && tj->base() == Type::AryPtr) ||

           (offset == arrayOopDesc::length_offset_in_bytes() && tj->base() == Type::AryPtr)  ,

           "For oops, klasses, raw offset must be constant; for arrays the offset is never known" );

   assert( tj->ptr() != TypePtr::TopPTR &&

           tj->ptr() != TypePtr::AnyNull &&

           tj->ptr() != TypePtr::Null, "No imprecise addresses" );

 //    assert( tj->ptr() != TypePtr::Constant ||

 //            tj->base() == Type::RawPtr ||

 //            tj->base() == Type::KlassPtr, "No constant oop addresses" );

   return tj;

 }

 void Compile::AliasType::Init(int i, const TypePtr* at) {

   _index = i;

   _adr_type = at;

   _field = NULL;

   _element = NULL;

   _is_rewritable = true; // default

   const TypeOopPtr *atoop = (at != NULL) ? at->isa_oopptr() : NULL;

   if (atoop != NULL && atoop->is_known_instance()) {

     const TypeOopPtr *gt = atoop->cast_to_instance_id(TypeOopPtr::InstanceBot);

     _general_index = Compile::current()->get_alias_index(gt);

   } else {

     _general_index = 0;

   }

 }

 BasicType Compile::AliasType::basic_type() const {

   if (element() != NULL) {

     const Type* element = adr_type()->is_aryptr()->elem();

     return element->isa_narrowoop() ? T_OBJECT : element->array_element_basic_type();

   } if (field() != NULL) {

     return field()->layout_type();

   } else {

     return T_ILLEGAL; // unknown

   }

 }

 //---------------------------------print_on------------------------------------

 #ifndef PRODUCT

 void Compile::AliasType::print_on(outputStream* st) {

   if (index() < 10)

         st->print("@ <%d> ", index());

   else  st->print("@ <%d>",  index());

   st->print(is_rewritable() ? "   " : " RO");

   int offset = adr_type()->offset();

   if (offset == Type::OffsetBot)

         st->print(" +any");

   else  st->print(" +%-3d", offset);

   st->print(" in ");

   adr_type()->dump_on(st);

   const TypeOopPtr* tjp = adr_type()->isa_oopptr();

   if (field() != NULL && tjp) {

     if (tjp->klass()  != field()->holder() ||

         tjp->offset() != field()->offset_in_bytes()) {

       st->print(" != ");

       field()->print();

       st->print(" ***");

     }

   }

 }

 void print_alias_types() {

   Compile* C = Compile::current();

   tty->print_cr("--- Alias types, AliasIdxBot .. %d", C->num_alias_types()-1);

   for (int idx = Compile::AliasIdxBot; idx < C->num_alias_types(); idx++) {

     C->alias_type(idx)->print_on(tty);

     tty->cr();

   }

 }

 #endif

 //----------------------------probe_alias_cache--------------------------------

 Compile::AliasCacheEntry* Compile::probe_alias_cache(const TypePtr* adr_type) {

   intptr_t key = (intptr_t) adr_type;

   key ^= key >> logAliasCacheSize;

   return &_alias_cache[key & right_n_bits(logAliasCacheSize)];

 }

 //-----------------------------grow_alias_types--------------------------------

 void Compile::grow_alias_types() {

   const int old_ats  = _max_alias_types; // how many before?

   const int new_ats  = old_ats;          // how many more?

   const int grow_ats = old_ats+new_ats;  // how many now?

   _max_alias_types = grow_ats;

   _alias_types =  REALLOC_ARENA_ARRAY(comp_arena(), AliasType*, _alias_types, old_ats, grow_ats);

   AliasType* ats =    NEW_ARENA_ARRAY(comp_arena(), AliasType, new_ats);

   Copy::zero_to_bytes(ats, sizeof(AliasType)*new_ats);

   for (int i = 0; i < new_ats; i++)  _alias_types[old_ats+i] = &ats[i];

 }

 //--------------------------------find_alias_type------------------------------

 Compile::AliasType* Compile::find_alias_type(const TypePtr* adr_type, bool no_create, ciField* original_field) {

   if (_AliasLevel == 0)

     return alias_type(AliasIdxBot);

   AliasCacheEntry* ace = probe_alias_cache(adr_type);

   if (ace->_adr_type == adr_type) {

     return alias_type(ace->_index);

   }

   // Handle special cases.

   if (adr_type == NULL)             return alias_type(AliasIdxTop);

   if (adr_type == TypePtr::BOTTOM)  return alias_type(AliasIdxBot);

   // Do it the slow way.

   const TypePtr* flat = flatten_alias_type(adr_type);

 #ifdef ASSERT

   {

     ResourceMark rm;

     assert(flat == flatten_alias_type(flat),

            err_msg("not idempotent: adr_type = %s; flat = %s => %s", Type::str(adr_type),

                    Type::str(flat), Type::str(flatten_alias_type(flat))));

     assert(flat != TypePtr::BOTTOM,

            err_msg("cannot alias-analyze an untyped ptr: adr_type = %s", Type::str(adr_type)));

     if (flat->isa_oopptr() && !flat->isa_klassptr()) {

       const TypeOopPtr* foop = flat->is_oopptr();

       // Scalarizable allocations have exact klass always.

       bool exact = !foop->klass_is_exact() || foop->is_known_instance();

       const TypePtr* xoop = foop->cast_to_exactness(exact)->is_ptr();

       assert(foop == flatten_alias_type(xoop),

              err_msg("exactness must not affect alias type: foop = %s; xoop = %s",

                      Type::str(foop), Type::str(xoop)));

     }

   }

 #endif

   int idx = AliasIdxTop;

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

     if (alias_type(i)->adr_type() == flat) {

       idx = i;

       break;

     }

   }

   if (idx == AliasIdxTop) {

     if (no_create)  return NULL;

     // Grow the array if necessary.

     if (_num_alias_types == _max_alias_types)  grow_alias_types();

     // Add a new alias type.

     idx = _num_alias_types++;

     _alias_types[idx]->Init(idx, flat);

     if (flat == TypeInstPtr::KLASS)  alias_type(idx)->set_rewritable(false);

     if (flat == TypeAryPtr::RANGE)   alias_type(idx)->set_rewritable(false);

     if (flat->isa_instptr()) {

       if (flat->offset() == java_lang_Class::klass_offset_in_bytes()

           && flat->is_instptr()->klass() == env()->Class_klass())

         alias_type(idx)->set_rewritable(false);

     }

     if (flat->isa_aryptr()) {

 #ifdef ASSERT

       const int header_size_min  = arrayOopDesc::base_offset_in_bytes(T_BYTE);

       // (T_BYTE has the weakest alignment and size restrictions...)

       assert(flat->offset() < header_size_min, "array body reference must be OffsetBot");

 #endif

       if (flat->offset() == TypePtr::OffsetBot) {

         alias_type(idx)->set_element(flat->is_aryptr()->elem());

       }

     }

     if (flat->isa_klassptr()) {

       if (flat->offset() == in_bytes(Klass::super_check_offset_offset()))

         alias_type(idx)->set_rewritable(false);

       if (flat->offset() == in_bytes(Klass::modifier_flags_offset()))

         alias_type(idx)->set_rewritable(false);

       if (flat->offset() == in_bytes(Klass::access_flags_offset()))

         alias_type(idx)->set_rewritable(false);

       if (flat->offset() == in_bytes(Klass::java_mirror_offset()))

         alias_type(idx)->set_rewritable(false);

     }

     // %%% (We would like to finalize JavaThread::threadObj_offset(),

     // but the base pointer type is not distinctive enough to identify

     // references into JavaThread.)

     // Check for final fields.

     const TypeInstPtr* tinst = flat->isa_instptr();

     if (tinst && tinst->offset() >= instanceOopDesc::base_offset_in_bytes()) {

       ciField* field;

       if (tinst->const_oop() != NULL &&

           tinst->klass() == ciEnv::current()->Class_klass() &&

           tinst->offset() >= (tinst->klass()->as_instance_klass()->size_helper() * wordSize)) {

         // static field

         ciInstanceKlass* k = tinst->const_oop()->as_instance()->java_lang_Class_klass()->as_instance_klass();

         field = k->get_field_by_offset(tinst->offset(), true);

       } else {

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

         field = k->get_field_by_offset(tinst->offset(), false);

       }

       assert(field == NULL ||

              original_field == NULL ||

              (field->holder() == original_field->holder() &&

               field->offset() == original_field->offset() &&

               field->is_static() == original_field->is_static()), "wrong field?");

       // Set field() and is_rewritable() attributes.

       if (field != NULL)  alias_type(idx)->set_field(field);

     }

   }

   // Fill the cache for next time.

   ace->_adr_type = adr_type;

   ace->_index    = idx;

   assert(alias_type(adr_type) == alias_type(idx),  "type must be installed");

   // Might as well try to fill the cache for the flattened version, too.

   AliasCacheEntry* face = probe_alias_cache(flat);

   if (face->_adr_type == NULL) {

     face->_adr_type = flat;

     face->_index    = idx;

     assert(alias_type(flat) == alias_type(idx), "flat type must work too");

   }

   return alias_type(idx);

 }

 Compile::AliasType* Compile::alias_type(ciField* field) {

   const TypeOopPtr* t;

   if (field->is_static())

     t = TypeInstPtr::make(field->holder()->java_mirror());

   else

     t = TypeOopPtr::make_from_klass_raw(field->holder());

   AliasType* atp = alias_type(t->add_offset(field->offset_in_bytes()), field);

   assert((field->is_final() || field->is_stable()) == !atp->is_rewritable(), "must get the rewritable bits correct");

   return atp;

 }

 //------------------------------have_alias_type--------------------------------

 bool Compile::have_alias_type(const TypePtr* adr_type) {

   AliasCacheEntry* ace = probe_alias_cache(adr_type);

   if (ace->_adr_type == adr_type) {

     return true;

   }

   // Handle special cases.

   if (adr_type == NULL)             return true;

   if (adr_type == TypePtr::BOTTOM)  return true;

   return find_alias_type(adr_type, true, NULL) != NULL;

 }

 //-----------------------------must_alias--------------------------------------

 // True if all values of the given address type are in the given alias category.

 bool Compile::must_alias(const TypePtr* adr_type, int alias_idx) {

   if (alias_idx == AliasIdxBot)         return true;  // the universal category

   if (adr_type == NULL)                 return true;  // NULL serves as TypePtr::TOP

   if (alias_idx == AliasIdxTop)         return false; // the empty category

   if (adr_type->base() == Type::AnyPtr) return false; // TypePtr::BOTTOM or its twins

   // the only remaining possible overlap is identity

   int adr_idx = get_alias_index(adr_type);

   assert(adr_idx != AliasIdxBot && adr_idx != AliasIdxTop, "");

   assert(adr_idx == alias_idx ||

          (alias_type(alias_idx)->adr_type() != TypeOopPtr::BOTTOM

           && adr_type                       != TypeOopPtr::BOTTOM),

          "should not be testing for overlap with an unsafe pointer");

   return adr_idx == alias_idx;

 }

 //------------------------------can_alias--------------------------------------

 // True if any values of the given address type are in the given alias category.

 bool Compile::can_alias(const TypePtr* adr_type, int alias_idx) {

   if (alias_idx == AliasIdxTop)         return false; // the empty category

   if (adr_type == NULL)                 return false; // NULL serves as TypePtr::TOP

   if (alias_idx == AliasIdxBot)         return true;  // the universal category

   if (adr_type->base() == Type::AnyPtr) return true;  // TypePtr::BOTTOM or its twins

   // the only remaining possible overlap is identity

   int adr_idx = get_alias_index(adr_type);

   assert(adr_idx != AliasIdxBot && adr_idx != AliasIdxTop, "");

   return adr_idx == alias_idx;

 }

 //---------------------------pop_warm_call-------------------------------------

 WarmCallInfo* Compile::pop_warm_call() {

   WarmCallInfo* wci = _warm_calls;

   if (wci != NULL)  _warm_calls = wci->remove_from(wci);

   return wci;

 }

 //----------------------------Inline_Warm--------------------------------------

 int Compile::Inline_Warm() {

   // If there is room, try to inline some more warm call sites.

   // %%% Do a graph index compaction pass when we think we're out of space?

   if (!InlineWarmCalls)  return 0;

   int calls_made_hot = 0;

   int room_to_grow   = NodeCountInliningCutoff - unique();

   int amount_to_grow = MIN2(room_to_grow, (int)NodeCountInliningStep);

   int amount_grown   = 0;

   WarmCallInfo* call;

   while (amount_to_grow > 0 && (call = pop_warm_call()) != NULL) {

     int est_size = (int)call->size();

     if (est_size > (room_to_grow - amount_grown)) {

       // This one won't fit anyway.  Get rid of it.

       call->make_cold();

       continue;

     }

     call->make_hot();

     calls_made_hot++;

     amount_grown   += est_size;

     amount_to_grow -= est_size;

   }

   if (calls_made_hot > 0)  set_major_progress();

   return calls_made_hot;

 }

 //----------------------------Finish_Warm--------------------------------------

 void Compile::Finish_Warm() {

   if (!InlineWarmCalls)  return;

   if (failing())  return;

   if (warm_calls() == NULL)  return;

   // Clean up loose ends, if we are out of space for inlining.

   WarmCallInfo* call;

   while ((call = pop_warm_call()) != NULL) {

     call->make_cold();

   }

 }

 //---------------------cleanup_loop_predicates-----------------------

 // Remove the opaque nodes that protect the predicates so that all unused

 // checks and uncommon_traps will be eliminated from the ideal graph

 void Compile::cleanup_loop_predicates(PhaseIterGVN &igvn) {

   if (predicate_count()==0) return;

   for (int i = predicate_count(); i > 0; i--) {

     Node * n = predicate_opaque1_node(i-1);

     assert(n->Opcode() == Op_Opaque1, "must be");

     igvn.replace_node(n, n->in(1));

   }

   assert(predicate_count()==0, "should be clean!");

 }

 void Compile::add_range_check_cast(Node* n) {

   assert(n->isa_CastII()->has_range_check(), "CastII should have range check dependency");

   assert(!_range_check_casts->contains(n), "duplicate entry in range check casts");

   _range_check_casts->append(n);

 }

 // Remove all range check dependent CastIINodes.

 void Compile::remove_range_check_casts(PhaseIterGVN &igvn) {

   for (int i = range_check_cast_count(); i > 0; i--) {

     Node* cast = range_check_cast_node(i-1);

     assert(cast->isa_CastII()->has_range_check(), "CastII should have range check dependency");

     igvn.replace_node(cast, cast->in(1));

   }

   assert(range_check_cast_count() == 0, "should be empty");

 }

 // StringOpts and late inlining of string methods

 void Compile::inline_string_calls(bool parse_time) {

   {

     // remove useless nodes to make the usage analysis simpler

     ResourceMark rm;

     PhaseRemoveUseless pru(initial_gvn(), for_igvn());

   }

   {

     ResourceMark rm;

     print_method(PHASE_BEFORE_STRINGOPTS, 3);

     PhaseStringOpts pso(initial_gvn(), for_igvn());

     print_method(PHASE_AFTER_STRINGOPTS, 3);

   }

   // now inline anything that we skipped the first time around

   if (!parse_time) {

     _late_inlines_pos = _late_inlines.length();

   }

   while (_string_late_inlines.length() > 0) {

     CallGenerator* cg = _string_late_inlines.pop();

     cg->do_late_inline();

     if (failing())  return;

   }

   _string_late_inlines.trunc_to(0);

 }

 // Late inlining of boxing methods

 void Compile::inline_boxing_calls(PhaseIterGVN& igvn) {

   if (_boxing_late_inlines.length() > 0) {

     assert(has_boxed_value(), "inconsistent");

     PhaseGVN* gvn = initial_gvn();

     set_inlining_incrementally(true);

     assert( igvn._worklist.size() == 0, "should be done with igvn" );

     for_igvn()->clear();

     gvn->replace_with(&igvn);

     _late_inlines_pos = _late_inlines.length();

     while (_boxing_late_inlines.length() > 0) {

       CallGenerator* cg = _boxing_late_inlines.pop();

       cg->do_late_inline();

       if (failing())  return;

     }

     _boxing_late_inlines.trunc_to(0);

     {

       ResourceMark rm;

       PhaseRemoveUseless pru(gvn, for_igvn());

     }

     igvn = PhaseIterGVN(gvn);

     igvn.optimize();

     set_inlining_progress(false);

     set_inlining_incrementally(false);

   }

 }

 void Compile::inline_incrementally_one(PhaseIterGVN& igvn) {

   assert(IncrementalInline, "incremental inlining should be on");

   PhaseGVN* gvn = initial_gvn();

   set_inlining_progress(false);

   for_igvn()->clear();

   gvn->replace_with(&igvn);

   int i = 0;

   for (; i <_late_inlines.length() && !inlining_progress(); i++) {

     CallGenerator* cg = _late_inlines.at(i);

     _late_inlines_pos = i+1;

     cg->do_late_inline();

     if (failing())  return;

   }

   int j = 0;

   for (; i < _late_inlines.length(); i++, j++) {

     _late_inlines.at_put(j, _late_inlines.at(i));

   }

   _late_inlines.trunc_to(j);

   {

     ResourceMark rm;

     PhaseRemoveUseless pru(gvn, for_igvn());

   }

   igvn = PhaseIterGVN(gvn);

 }

 // Perform incremental inlining until bound on number of live nodes is reached

 void Compile::inline_incrementally(PhaseIterGVN& igvn) {

   PhaseGVN* gvn = initial_gvn();

   set_inlining_incrementally(true);

   set_inlining_progress(true);

   uint low_live_nodes = 0;

   while(inlining_progress() && _late_inlines.length() > 0) {

     if (live_nodes() > (uint)LiveNodeCountInliningCutoff) {

       if (low_live_nodes < (uint)LiveNodeCountInliningCutoff * 8 / 10) {

         // PhaseIdealLoop is expensive so we only try it once we are

         // out of live nodes and we only try it again if the previous

         // helped got the number of nodes down significantly

         PhaseIdealLoop ideal_loop( igvn, false, true );

         if (failing())  return;

         low_live_nodes = live_nodes();

         _major_progress = true;

       }

       if (live_nodes() > (uint)LiveNodeCountInliningCutoff) {

         break;

       }

     }

     inline_incrementally_one(igvn);

     if (failing())  return;

     igvn.optimize();

     if (failing())  return;

   }

   assert( igvn._worklist.size() == 0, "should be done with igvn" );

   if (_string_late_inlines.length() > 0) {

     assert(has_stringbuilder(), "inconsistent");

     for_igvn()->clear();

     initial_gvn()->replace_with(&igvn);

     inline_string_calls(false);

     if (failing())  return;

     {

       ResourceMark rm;

       PhaseRemoveUseless pru(initial_gvn(), for_igvn());

     }

     igvn = PhaseIterGVN(gvn);

     igvn.optimize();

   }

   set_inlining_incrementally(false);

 }

 // Remove edges from "root" to each SafePoint at a backward branch.

 // They were inserted during parsing (see add_safepoint()) to make

 // infinite loops without calls or exceptions visible to root, i.e.,

 // useful.

 void Compile::remove_root_to_sfpts_edges() {

   Node *r = root();

   if (r != NULL) {

     for (uint i = r->req(); i < r->len(); ++i) {

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

       if (n != NULL && n->is_SafePoint()) {

         r->rm_prec(i);

         --i;

       }

     }

   }

 }

 //------------------------------Optimize---------------------------------------

 // Given a graph, optimize it.

 void Compile::Optimize() {

   TracePhase t1("optimizer", &_t_optimizer, true);

 #ifndef PRODUCT

   if (env()->break_at_compile()) {

     BREAKPOINT;

   }

 #endif

   ResourceMark rm;

   int          loop_opts_cnt;

   NOT_PRODUCT( verify_graph_edges(); )

   print_method(PHASE_AFTER_PARSING);

  {

   // Iterative Global Value Numbering, including ideal transforms

   // Initialize IterGVN with types and values from parse-time GVN

   PhaseIterGVN igvn(initial_gvn());

   {

     NOT_PRODUCT( TracePhase t2("iterGVN", &_t_iterGVN, TimeCompiler); )

     igvn.optimize();

   }

   print_method(PHASE_ITER_GVN1, 2);

   if (failing())  return;

   {

     NOT_PRODUCT( TracePhase t2("incrementalInline", &_t_incrInline, TimeCompiler); )

     inline_incrementally(igvn);

   }

   print_method(PHASE_INCREMENTAL_INLINE, 2);

   if (failing())  return;

   if (eliminate_boxing()) {

     NOT_PRODUCT( TracePhase t2("incrementalInline", &_t_incrInline, TimeCompiler); )

     // Inline valueOf() methods now.

     inline_boxing_calls(igvn);

     if (AlwaysIncrementalInline) {

       inline_incrementally(igvn);

     }

     print_method(PHASE_INCREMENTAL_BOXING_INLINE, 2);

     if (failing())  return;

   }

   // Now that all inlining is over, cut edge from root to loop

   // safepoints

   remove_root_to_sfpts_edges();

   // Remove the speculative part of types and clean up the graph from

   // the extra CastPP nodes whose only purpose is to carry them. Do

   // that early so that optimizations are not disrupted by the extra

   // CastPP nodes.

   remove_speculative_types(igvn);

   // No more new expensive nodes will be added to the list from here

   // so keep only the actual candidates for optimizations.

   cleanup_expensive_nodes(igvn);

   if (!failing() && RenumberLiveNodes && live_nodes() + NodeLimitFudgeFactor < unique()) {

     NOT_PRODUCT(Compile::TracePhase t2("", &_t_renumberLive, TimeCompiler);)

     initial_gvn()->replace_with(&igvn);

     for_igvn()->clear();

     Unique_Node_List new_worklist(C->comp_arena());

     {

       ResourceMark rm;

       PhaseRenumberLive prl = PhaseRenumberLive(initial_gvn(), for_igvn(), &new_worklist);

     }

     set_for_igvn(&new_worklist);

     igvn = PhaseIterGVN(initial_gvn());

     igvn.optimize();

   }

   // Perform escape analysis

   if (_do_escape_analysis && ConnectionGraph::has_candidates(this)) {

     if (has_loops()) {

       // Cleanup graph (remove dead nodes).

       TracePhase t2("idealLoop", &_t_idealLoop, true);

       PhaseIdealLoop ideal_loop( igvn, false, true );

       if (major_progress()) print_method(PHASE_PHASEIDEAL_BEFORE_EA, 2);

       if (failing())  return;

     }

     ConnectionGraph::do_analysis(this, &igvn);

     if (failing())  return;

     // Optimize out fields loads from scalar replaceable allocations.

     igvn.optimize();

     print_method(PHASE_ITER_GVN_AFTER_EA, 2);

     if (failing())  return;

     if (congraph() != NULL && macro_count() > 0) {

       NOT_PRODUCT( TracePhase t2("macroEliminate", &_t_macroEliminate, TimeCompiler); )

       PhaseMacroExpand mexp(igvn);

       mexp.eliminate_macro_nodes();

       igvn.set_delay_transform(false);

       igvn.optimize();

       print_method(PHASE_ITER_GVN_AFTER_ELIMINATION, 2);

       if (failing())  return;

     }

   }

   // Loop transforms on the ideal graph.  Range Check Elimination,

   // peeling, unrolling, etc.

   // Set loop opts counter

   loop_opts_cnt = num_loop_opts();

   if((loop_opts_cnt > 0) && (has_loops() || has_split_ifs())) {

     {

       TracePhase t2("idealLoop", &_t_idealLoop, true);

       PhaseIdealLoop ideal_loop( igvn, true );

       loop_opts_cnt--;

       if (major_progress()) print_method(PHASE_PHASEIDEALLOOP1, 2);

       if (failing())  return;

     }

     // Loop opts pass if partial peeling occurred in previous pass

     if(PartialPeelLoop && major_progress() && (loop_opts_cnt > 0)) {

       TracePhase t3("idealLoop", &_t_idealLoop, true);

       PhaseIdealLoop ideal_loop( igvn, false );

       loop_opts_cnt--;

       if (major_progress()) print_method(PHASE_PHASEIDEALLOOP2, 2);

       if (failing())  return;

     }

     // Loop opts pass for loop-unrolling before CCP

     if(major_progress() && (loop_opts_cnt > 0)) {

       TracePhase t4("idealLoop", &_t_idealLoop, true);

       PhaseIdealLoop ideal_loop( igvn, false );

       loop_opts_cnt--;

       if (major_progress()) print_method(PHASE_PHASEIDEALLOOP3, 2);

     }

     if (!failing()) {

       // Verify that last round of loop opts produced a valid graph

       NOT_PRODUCT( TracePhase t2("idealLoopVerify", &_t_idealLoopVerify, TimeCompiler); )

       PhaseIdealLoop::verify(igvn);

     }

   }

   if (failing())  return;

   // Conditional Constant Propagation;

   PhaseCCP ccp( &igvn );

   assert( true, "Break here to ccp.dump_nodes_and_types(_root,999,1)");

   {

     TracePhase t2("ccp", &_t_ccp, true);

     ccp.do_transform();

   }

   print_method(PHASE_CPP1, 2);

   assert( true, "Break here to ccp.dump_old2new_map()");

   // Iterative Global Value Numbering, including ideal transforms

   {

     NOT_PRODUCT( TracePhase t2("iterGVN2", &_t_iterGVN2, TimeCompiler); )

     igvn = ccp;

     igvn.optimize();

   }

   print_method(PHASE_ITER_GVN2, 2);

   if (failing())  return;

   // Loop transforms on the ideal graph.  Range Check Elimination,

   // peeling, unrolling, etc.

   if(loop_opts_cnt > 0) {

     debug_only( int cnt = 0; );

     while(major_progress() && (loop_opts_cnt > 0)) {

       TracePhase t2("idealLoop", &_t_idealLoop, true);

       assert( cnt++ < 40, "infinite cycle in loop optimization" );

       PhaseIdealLoop ideal_loop( igvn, true);

       loop_opts_cnt--;

       if (major_progress()) print_method(PHASE_PHASEIDEALLOOP_ITERATIONS, 2);

       if (failing())  return;

     }

   }

   {

     // Verify that all previous optimizations produced a valid graph

     // at least to this point, even if no loop optimizations were done.

     NOT_PRODUCT( TracePhase t2("idealLoopVerify", &_t_idealLoopVerify, TimeCompiler); )

     PhaseIdealLoop::verify(igvn);

   }

   if (range_check_cast_count() > 0) {

     // No more loop optimizations. Remove all range check dependent CastIINodes.

     C->remove_range_check_casts(igvn);

     igvn.optimize();

   }

   {

     NOT_PRODUCT( TracePhase t2("macroExpand", &_t_macroExpand, TimeCompiler); )

     PhaseMacroExpand  mex(igvn);

     if (mex.expand_macro_nodes()) {

       assert(failing(), "must bail out w/ explicit message");

       return;

     }

   }

  } // (End scope of igvn; run destructor if necessary for asserts.)

   dump_inlining();

   // A method with only infinite loops has no edges entering loops from root

   {

     NOT_PRODUCT( TracePhase t2("graphReshape", &_t_graphReshaping, TimeCompiler); )

     if (final_graph_reshaping()) {

       assert(failing(), "must bail out w/ explicit message");

       return;

     }

   }

   print_method(PHASE_OPTIMIZE_FINISHED, 2);

 }

 //------------------------------Code_Gen---------------------------------------

 // Given a graph, generate code for it

 void Compile::Code_Gen() {

   if (failing()) {

     return;

   }

   // Perform instruction selection.  You might think we could reclaim Matcher

   // memory PDQ, but actually the Matcher is used in generating spill code.

   // Internals of the Matcher (including some VectorSets) must remain live

   // for awhile - thus I cannot reclaim Matcher memory lest a VectorSet usage

   // set a bit in reclaimed memory.

   // In debug mode can dump m._nodes.dump() for mapping of ideal to machine

   // nodes.  Mapping is only valid at the root of each matched subtree.

   NOT_PRODUCT( verify_graph_edges(); )

   Matcher matcher;

   _matcher = &matcher;

   {

     TracePhase t2("matcher", &_t_matcher, true);

     matcher.match();

   }

   // In debug mode can dump m._nodes.dump() for mapping of ideal to machine

   // nodes.  Mapping is only valid at the root of each matched subtree.

   NOT_PRODUCT( verify_graph_edges(); )

   // If you have too many nodes, or if matching has failed, bail out

   check_node_count(0, "out of nodes matching instructions");

   if (failing()) {

     return;

   }

   // Build a proper-looking CFG

   PhaseCFG cfg(node_arena(), root(), matcher);

   _cfg = &cfg;

   {

     NOT_PRODUCT( TracePhase t2("scheduler", &_t_scheduler, TimeCompiler); )

     bool success = cfg.do_global_code_motion();

     if (!success) {

       return;

     }

     print_method(PHASE_GLOBAL_CODE_MOTION, 2);

     NOT_PRODUCT( verify_graph_edges(); )

     debug_only( cfg.verify(); )

   }

   PhaseChaitin regalloc(unique(), cfg, matcher);

   _regalloc = &regalloc;

   {

     TracePhase t2("regalloc", &_t_registerAllocation, true);

     // Perform register allocation.  After Chaitin, use-def chains are

     // no longer accurate (at spill code) and so must be ignored.

     // Node->LRG->reg mappings are still accurate.

     _regalloc->Register_Allocate();

     // Bail out if the allocator builds too many nodes

     if (failing()) {

       return;

     }

   }

   // Prior to register allocation we kept empty basic blocks in case the

   // the allocator needed a place to spill.  After register allocation we

   // are not adding any new instructions.  If any basic block is empty, we

   // can now safely remove it.

   {

     NOT_PRODUCT( TracePhase t2("blockOrdering", &_t_blockOrdering, TimeCompiler); )

     cfg.remove_empty_blocks();

     if (do_freq_based_layout()) {

       PhaseBlockLayout layout(cfg);

     } else {

       cfg.set_loop_alignment();

     }

     cfg.fixup_flow();

   }

   // Apply peephole optimizations

   if( OptoPeephole ) {

     NOT_PRODUCT( TracePhase t2("peephole", &_t_peephole, TimeCompiler); )

     PhasePeephole peep( _regalloc, cfg);

     peep.do_transform();

   }

   // Do late expand if CPU requires this.

   if (Matcher::require_postalloc_expand) {

     NOT_PRODUCT(TracePhase t2c("postalloc_expand", &_t_postalloc_expand, true));

     cfg.postalloc_expand(_regalloc);

   }

   // Convert Nodes to instruction bits in a buffer

   {

     // %%%% workspace merge brought two timers together for one job

     TracePhase t2a("output", &_t_output, true);

     NOT_PRODUCT( TraceTime t2b(NULL, &_t_codeGeneration, TimeCompiler, false); )

     Output();

   }

   print_method(PHASE_FINAL_CODE);

   // He's dead, Jim.

   _cfg     = (PhaseCFG*)((intptr_t)0xdeadbeef);

   _regalloc = (PhaseChaitin*)((intptr_t)0xdeadbeef);

 }

 //------------------------------dump_asm---------------------------------------

 // Dump formatted assembly

 #ifndef PRODUCT

 void Compile::dump_asm(int *pcs, uint pc_limit) {

   bool cut_short = false;

   tty->print_cr("#");

   tty->print("#  ");  _tf->dump();  tty->cr();

   tty->print_cr("#");

   // For all blocks

   int pc = 0x0;                 // Program counter

   char starts_bundle = ' ';

   _regalloc->dump_frame();

   Node *n = NULL;

   for (uint i = 0; i < _cfg->number_of_blocks(); i++) {

     if (VMThread::should_terminate()) {

       cut_short = true;

       break;

     }

     Block* block = _cfg->get_block(i);

     if (block->is_connector() && !Verbose) {

       continue;

     }

     n = block->head();

     if (pcs && n->_idx < pc_limit) {

       tty->print("%3.3x   ", pcs[n->_idx]);

     } else {

       tty->print("      ");

     }

     block->dump_head(_cfg);

     if (block->is_connector()) {

       tty->print_cr("        # Empty connector block");

     } else if (block->num_preds() == 2 && block->pred(1)->is_CatchProj() && block->pred(1)->as_CatchProj()->_con == CatchProjNode::fall_through_index) {

       tty->print_cr("        # Block is sole successor of call");

     }

     // For all instructions

     Node *delay = NULL;

     for (uint j = 0; j < block->number_of_nodes(); j++) {

       if (VMThread::should_terminate()) {

         cut_short = true;

         break;

       }

       n = block->get_node(j);

       if (valid_bundle_info(n)) {

         Bundle* bundle = node_bundling(n);

         if (bundle->used_in_unconditional_delay()) {

           delay = n;

           continue;

         }

         if (bundle->starts_bundle()) {

           starts_bundle = '+';

         }

       }

       if (WizardMode) {

         n->dump();

       }

       if( !n->is_Region() &&    // Dont print in the Assembly

           !n->is_Phi() &&       // a few noisely useless nodes

           !n->is_Proj() &&

           !n->is_MachTemp() &&

           !n->is_SafePointScalarObject() &&

           !n->is_Catch() &&     // Would be nice to print exception table targets

           !n->is_MergeMem() &&  // Not very interesting

           !n->is_top() &&       // Debug info table constants

           !(n->is_Con() && !n->is_Mach())// Debug info table constants

           ) {

         if (pcs && n->_idx < pc_limit)

           tty->print("%3.3x", pcs[n->_idx]);

         else

           tty->print("   ");

         tty->print(" %c ", starts_bundle);

         starts_bundle = ' ';

         tty->print("\t");

         n->format(_regalloc, tty);

         tty->cr();

       }

       // If we have an instruction with a delay slot, and have seen a delay,

       // then back up and print it

       if (valid_bundle_info(n) && node_bundling(n)->use_unconditional_delay()) {

         assert(delay != NULL, "no unconditional delay instruction");

         if (WizardMode) delay->dump();

         if (node_bundling(delay)->starts_bundle())

           starts_bundle = '+';

         if (pcs && n->_idx < pc_limit)

           tty->print("%3.3x", pcs[n->_idx]);

         else

           tty->print("   ");

         tty->print(" %c ", starts_bundle);

         starts_bundle = ' ';

         tty->print("\t");

         delay->format(_regalloc, tty);

         tty->cr();

         delay = NULL;

       }

       // Dump the exception table as well

       if( n->is_Catch() && (Verbose || WizardMode) ) {

         // Print the exception table for this offset

         _handler_table.print_subtable_for(pc);

       }

     }

     if (pcs && n->_idx < pc_limit)

       tty->print_cr("%3.3x", pcs[n->_idx]);

     else

       tty->cr();

     assert(cut_short || delay == NULL, "no unconditional delay branch");

   } // End of per-block dump

   tty->cr();

   if (cut_short)  tty->print_cr("*** disassembly is cut short ***");

 }

 #endif

 //------------------------------Final_Reshape_Counts---------------------------

 // This class defines counters to help identify when a method

 // may/must be executed using hardware with only 24-bit precision.

 struct Final_Reshape_Counts : public StackObj {

   int  _call_count;             // count non-inlined 'common' calls

   int  _float_count;            // count float ops requiring 24-bit precision

   int  _double_count;           // count double ops requiring more precision

   int  _java_call_count;        // count non-inlined 'java' calls

   int  _inner_loop_count;       // count loops which need alignment

   VectorSet _visited;           // Visitation flags

   Node_List _tests;             // Set of IfNodes & PCTableNodes

   Final_Reshape_Counts() :

     _call_count(0), _float_count(0), _double_count(0),

     _java_call_count(0), _inner_loop_count(0),

     _visited( Thread::current()->resource_area() ) { }

   void inc_call_count  () { _call_count  ++; }

   void inc_float_count () { _float_count ++; }

   void inc_double_count() { _double_count++; }

   void inc_java_call_count() { _java_call_count++; }

   void inc_inner_loop_count() { _inner_loop_count++; }

   int  get_call_count  () const { return _call_count  ; }

   int  get_float_count () const { return _float_count ; }

   int  get_double_count() const { return _double_count; }

   int  get_java_call_count() const { return _java_call_count; }

   int  get_inner_loop_count() const { return _inner_loop_count; }

 };

 #ifdef ASSERT

 static bool oop_offset_is_sane(const TypeInstPtr* tp) {

   ciInstanceKlass *k = tp->klass()->as_instance_klass();

   // Make sure the offset goes inside the instance layout.

   return k->contains_field_offset(tp->offset());

   // Note that OffsetBot and OffsetTop are very negative.

 }

 #endif

 // Eliminate trivially redundant StoreCMs and accumulate their

 // precedence edges.

 void Compile::eliminate_redundant_card_marks(Node* n) {

   assert(n->Opcode() == Op_StoreCM, "expected StoreCM");

   if (n->in(MemNode::Address)->outcnt() > 1) {

     // There are multiple users of the same address so it might be

     // possible to eliminate some of the StoreCMs

     Node* mem = n->in(MemNode::Memory);

     Node* adr = n->in(MemNode::Address);

     Node* val = n->in(MemNode::ValueIn);

     Node* prev = n;

     bool done = false;

     // Walk the chain of StoreCMs eliminating ones that match.  As

     // long as it's a chain of single users then the optimization is

     // safe.  Eliminating partially redundant StoreCMs would require

     // cloning copies down the other paths.

     while (mem->Opcode() == Op_StoreCM && mem->outcnt() == 1 && !done) {

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

           val == mem->in(MemNode::ValueIn)) {

         // redundant StoreCM

         if (mem->req() > MemNode::OopStore) {

           // Hasn't been processed by this code yet.

           n->add_prec(mem->in(MemNode::OopStore));

         } else {

           // Already converted to precedence edge

           for (uint i = mem->req(); i < mem->len(); i++) {

             // Accumulate any precedence edges

             if (mem->in(i) != NULL) {

               n->add_prec(mem->in(i));

             }

           }

           // Everything above this point has been processed.

           done = true;

         }

         // Eliminate the previous StoreCM

         prev->set_req(MemNode::Memory, mem->in(MemNode::Memory));

         assert(mem->outcnt() == 0, "should be dead");

         mem->disconnect_inputs(NULL, this);

       } else {

         prev = mem;

       }

       mem = prev->in(MemNode::Memory);

     }

   }

 }

 //------------------------------final_graph_reshaping_impl----------------------

 // Implement items 1-5 from final_graph_reshaping below.

 void Compile::final_graph_reshaping_impl( Node *n, Final_Reshape_Counts &frc) {

   if ( n->outcnt() == 0 ) return; // dead node

   uint nop = n->Opcode();

   // Check for 2-input instruction with "last use" on right input.

   // Swap to left input.  Implements item (2).