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 /*

  * Copyright (c) 1999, 2011, 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 "c1/c1_CFGPrinter.hpp"

 #include "c1/c1_Canonicalizer.hpp"

 #include "c1/c1_Compilation.hpp"

 #include "c1/c1_GraphBuilder.hpp"

 #include "c1/c1_InstructionPrinter.hpp"

 #include "ci/ciField.hpp"

 #include "ci/ciKlass.hpp"

 #include "interpreter/bytecode.hpp"

 #include "runtime/sharedRuntime.hpp"

 #include "utilities/bitMap.inline.hpp"

 class BlockListBuilder VALUE_OBJ_CLASS_SPEC {

  private:

   Compilation* _compilation;

   IRScope*     _scope;

   BlockList    _blocks;                // internal list of all blocks

   BlockList*   _bci2block;             // mapping from bci to blocks for GraphBuilder

   // fields used by mark_loops

   BitMap       _active;                // for iteration of control flow graph

   BitMap       _visited;               // for iteration of control flow graph

   intArray     _loop_map;              // caches the information if a block is contained in a loop

   int          _next_loop_index;       // next free loop number

   int          _next_block_number;     // for reverse postorder numbering of blocks

   // accessors

   Compilation*  compilation() const              { return _compilation; }

   IRScope*      scope() const                    { return _scope; }

   ciMethod*     method() const                   { return scope()->method(); }

   XHandlers*    xhandlers() const                { return scope()->xhandlers(); }

   // unified bailout support

   void          bailout(const char* msg) const   { compilation()->bailout(msg); }

   bool          bailed_out() const               { return compilation()->bailed_out(); }

   // helper functions

   BlockBegin* make_block_at(int bci, BlockBegin* predecessor);

   void handle_exceptions(BlockBegin* current, int cur_bci);

   void handle_jsr(BlockBegin* current, int sr_bci, int next_bci);

   void store_one(BlockBegin* current, int local);

   void store_two(BlockBegin* current, int local);

   void set_entries(int osr_bci);

   void set_leaders();

   void make_loop_header(BlockBegin* block);

   void mark_loops();

   int  mark_loops(BlockBegin* b, bool in_subroutine);

   // debugging

 #ifndef PRODUCT

   void print();

 #endif

  public:

   // creation

   BlockListBuilder(Compilation* compilation, IRScope* scope, int osr_bci);

   // accessors for GraphBuilder

   BlockList*    bci2block() const                { return _bci2block; }

 };

 // Implementation of BlockListBuilder

 BlockListBuilder::BlockListBuilder(Compilation* compilation, IRScope* scope, int osr_bci)

  : _compilation(compilation)

  , _scope(scope)

  , _blocks(16)

  , _bci2block(new BlockList(scope->method()->code_size(), NULL))

  , _next_block_number(0)

  , _active()         // size not known yet

  , _visited()        // size not known yet

  , _next_loop_index(0)

  , _loop_map() // size not known yet

 {

   set_entries(osr_bci);

   set_leaders();

   CHECK_BAILOUT();

   mark_loops();

   NOT_PRODUCT(if (PrintInitialBlockList) print());

 #ifndef PRODUCT

   if (PrintCFGToFile) {

     stringStream title;

     title.print("BlockListBuilder ");

     scope->method()->print_name(&title);

     CFGPrinter::print_cfg(_bci2block, title.as_string(), false, false);

   }

 #endif

 }

 void BlockListBuilder::set_entries(int osr_bci) {

   // generate start blocks

   BlockBegin* std_entry = make_block_at(0, NULL);

   if (scope()->caller() == NULL) {

     std_entry->set(BlockBegin::std_entry_flag);

   }

   if (osr_bci != -1) {

     BlockBegin* osr_entry = make_block_at(osr_bci, NULL);

     osr_entry->set(BlockBegin::osr_entry_flag);

   }

   // generate exception entry blocks

   XHandlers* list = xhandlers();

   const int n = list->length();

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

     XHandler* h = list->handler_at(i);

     BlockBegin* entry = make_block_at(h->handler_bci(), NULL);

     entry->set(BlockBegin::exception_entry_flag);

     h->set_entry_block(entry);

   }

 }

 BlockBegin* BlockListBuilder::make_block_at(int cur_bci, BlockBegin* predecessor) {

   assert(method()->bci_block_start().at(cur_bci), "wrong block starts of MethodLivenessAnalyzer");

   BlockBegin* block = _bci2block->at(cur_bci);

   if (block == NULL) {

     block = new BlockBegin(cur_bci);

     block->init_stores_to_locals(method()->max_locals());

     _bci2block->at_put(cur_bci, block);

     _blocks.append(block);

     assert(predecessor == NULL || predecessor->bci() < cur_bci, "targets for backward branches must already exist");

   }

   if (predecessor != NULL) {

     if (block->is_set(BlockBegin::exception_entry_flag)) {

       BAILOUT_("Exception handler can be reached by both normal and exceptional control flow", block);

     }

     predecessor->add_successor(block);

     block->increment_total_preds();

   }

   return block;

 }

 inline void BlockListBuilder::store_one(BlockBegin* current, int local) {

   current->stores_to_locals().set_bit(local);

 }

 inline void BlockListBuilder::store_two(BlockBegin* current, int local) {

   store_one(current, local);

   store_one(current, local + 1);

 }

 void BlockListBuilder::handle_exceptions(BlockBegin* current, int cur_bci) {

   // Draws edges from a block to its exception handlers

   XHandlers* list = xhandlers();

   const int n = list->length();

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

     XHandler* h = list->handler_at(i);

     if (h->covers(cur_bci)) {

       BlockBegin* entry = h->entry_block();

       assert(entry != NULL && entry == _bci2block->at(h->handler_bci()), "entry must be set");

       assert(entry->is_set(BlockBegin::exception_entry_flag), "flag must be set");

       // add each exception handler only once

       if (!current->is_successor(entry)) {

         current->add_successor(entry);

         entry->increment_total_preds();

       }

       // stop when reaching catchall

       if (h->catch_type() == 0) break;

     }

   }

 }

 void BlockListBuilder::handle_jsr(BlockBegin* current, int sr_bci, int next_bci) {

   // start a new block after jsr-bytecode and link this block into cfg

   make_block_at(next_bci, current);

   // start a new block at the subroutine entry at mark it with special flag

   BlockBegin* sr_block = make_block_at(sr_bci, current);

   if (!sr_block->is_set(BlockBegin::subroutine_entry_flag)) {

     sr_block->set(BlockBegin::subroutine_entry_flag);

   }

 }

 void BlockListBuilder::set_leaders() {

   bool has_xhandlers = xhandlers()->has_handlers();

   BlockBegin* current = NULL;

   // The information which bci starts a new block simplifies the analysis

   // Without it, backward branches could jump to a bci where no block was created

   // during bytecode iteration. This would require the creation of a new block at the

   // branch target and a modification of the successor lists.

   BitMap bci_block_start = method()->bci_block_start();

   ciBytecodeStream s(method());

   while (s.next() != ciBytecodeStream::EOBC()) {

     int cur_bci = s.cur_bci();

     if (bci_block_start.at(cur_bci)) {

       current = make_block_at(cur_bci, current);

     }

     assert(current != NULL, "must have current block");

     if (has_xhandlers && GraphBuilder::can_trap(method(), s.cur_bc())) {

       handle_exceptions(current, cur_bci);

     }

     switch (s.cur_bc()) {

       // track stores to local variables for selective creation of phi functions

       case Bytecodes::_iinc:     store_one(current, s.get_index()); break;

       case Bytecodes::_istore:   store_one(current, s.get_index()); break;

       case Bytecodes::_lstore:   store_two(current, s.get_index()); break;

       case Bytecodes::_fstore:   store_one(current, s.get_index()); break;

       case Bytecodes::_dstore:   store_two(current, s.get_index()); break;

       case Bytecodes::_astore:   store_one(current, s.get_index()); break;

       case Bytecodes::_istore_0: store_one(current, 0); break;

       case Bytecodes::_istore_1: store_one(current, 1); break;

       case Bytecodes::_istore_2: store_one(current, 2); break;

       case Bytecodes::_istore_3: store_one(current, 3); break;

       case Bytecodes::_lstore_0: store_two(current, 0); break;

       case Bytecodes::_lstore_1: store_two(current, 1); break;

       case Bytecodes::_lstore_2: store_two(current, 2); break;

       case Bytecodes::_lstore_3: store_two(current, 3); break;

       case Bytecodes::_fstore_0: store_one(current, 0); break;

       case Bytecodes::_fstore_1: store_one(current, 1); break;

       case Bytecodes::_fstore_2: store_one(current, 2); break;

       case Bytecodes::_fstore_3: store_one(current, 3); break;

       case Bytecodes::_dstore_0: store_two(current, 0); break;

       case Bytecodes::_dstore_1: store_two(current, 1); break;

       case Bytecodes::_dstore_2: store_two(current, 2); break;

       case Bytecodes::_dstore_3: store_two(current, 3); break;

       case Bytecodes::_astore_0: store_one(current, 0); break;

       case Bytecodes::_astore_1: store_one(current, 1); break;

       case Bytecodes::_astore_2: store_one(current, 2); break;

       case Bytecodes::_astore_3: store_one(current, 3); break;

       // track bytecodes that affect the control flow

       case Bytecodes::_athrow:  // fall through

       case Bytecodes::_ret:     // fall through

       case Bytecodes::_ireturn: // fall through

       case Bytecodes::_lreturn: // fall through

       case Bytecodes::_freturn: // fall through

       case Bytecodes::_dreturn: // fall through

       case Bytecodes::_areturn: // fall through

       case Bytecodes::_return:

         current = NULL;

         break;

       case Bytecodes::_ifeq:      // fall through

       case Bytecodes::_ifne:      // fall through

       case Bytecodes::_iflt:      // fall through

       case Bytecodes::_ifge:      // fall through

       case Bytecodes::_ifgt:      // fall through

       case Bytecodes::_ifle:      // fall through

       case Bytecodes::_if_icmpeq: // fall through

       case Bytecodes::_if_icmpne: // fall through

       case Bytecodes::_if_icmplt: // fall through

       case Bytecodes::_if_icmpge: // fall through

       case Bytecodes::_if_icmpgt: // fall through

       case Bytecodes::_if_icmple: // fall through

       case Bytecodes::_if_acmpeq: // fall through

       case Bytecodes::_if_acmpne: // fall through

       case Bytecodes::_ifnull:    // fall through

       case Bytecodes::_ifnonnull:

         make_block_at(s.next_bci(), current);

         make_block_at(s.get_dest(), current);

         current = NULL;

         break;

       case Bytecodes::_goto:

         make_block_at(s.get_dest(), current);

         current = NULL;

         break;

       case Bytecodes::_goto_w:

         make_block_at(s.get_far_dest(), current);

         current = NULL;

         break;

       case Bytecodes::_jsr:

         handle_jsr(current, s.get_dest(), s.next_bci());

         current = NULL;

         break;

       case Bytecodes::_jsr_w:

         handle_jsr(current, s.get_far_dest(), s.next_bci());

         current = NULL;

         break;

       case Bytecodes::_tableswitch: {

         // set block for each case

         Bytecode_tableswitch sw(&s);

         int l = sw.length();

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

           make_block_at(cur_bci + sw.dest_offset_at(i), current);

         }

         make_block_at(cur_bci + sw.default_offset(), current);

         current = NULL;

         break;

       }

       case Bytecodes::_lookupswitch: {

         // set block for each case

         Bytecode_lookupswitch sw(&s);

         int l = sw.number_of_pairs();

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

           make_block_at(cur_bci + sw.pair_at(i).offset(), current);

         }

         make_block_at(cur_bci + sw.default_offset(), current);

         current = NULL;

         break;

       }

     }

   }

 }

 void BlockListBuilder::mark_loops() {

   ResourceMark rm;

   _active = BitMap(BlockBegin::number_of_blocks());         _active.clear();

   _visited = BitMap(BlockBegin::number_of_blocks());        _visited.clear();

   _loop_map = intArray(BlockBegin::number_of_blocks(), 0);

   _next_loop_index = 0;

   _next_block_number = _blocks.length();

   // recursively iterate the control flow graph

   mark_loops(_bci2block->at(0), false);

   assert(_next_block_number >= 0, "invalid block numbers");

 }

 void BlockListBuilder::make_loop_header(BlockBegin* block) {

   if (block->is_set(BlockBegin::exception_entry_flag)) {

     // exception edges may look like loops but don't mark them as such

     // since it screws up block ordering.

     return;

   }

   if (!block->is_set(BlockBegin::parser_loop_header_flag)) {

     block->set(BlockBegin::parser_loop_header_flag);

     assert(_loop_map.at(block->block_id()) == 0, "must not be set yet");

     assert(0 <= _next_loop_index && _next_loop_index < BitsPerInt, "_next_loop_index is used as a bit-index in integer");

     _loop_map.at_put(block->block_id(), 1 << _next_loop_index);

     if (_next_loop_index < 31) _next_loop_index++;

   } else {

     // block already marked as loop header

     assert(is_power_of_2((unsigned int)_loop_map.at(block->block_id())), "exactly one bit must be set");

   }

 }

 int BlockListBuilder::mark_loops(BlockBegin* block, bool in_subroutine) {

   int block_id = block->block_id();

   if (_visited.at(block_id)) {

     if (_active.at(block_id)) {

       // reached block via backward branch

       make_loop_header(block);

     }

     // return cached loop information for this block

     return _loop_map.at(block_id);

   }

   if (block->is_set(BlockBegin::subroutine_entry_flag)) {

     in_subroutine = true;

   }

   // set active and visited bits before successors are processed

   _visited.set_bit(block_id);

   _active.set_bit(block_id);

   intptr_t loop_state = 0;

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

     // recursively process all successors

     loop_state |= mark_loops(block->sux_at(i), in_subroutine);

   }

   // clear active-bit after all successors are processed

   _active.clear_bit(block_id);

   // reverse-post-order numbering of all blocks

   block->set_depth_first_number(_next_block_number);

   _next_block_number--;

   if (loop_state != 0 || in_subroutine ) {

     // block is contained at least in one loop, so phi functions are necessary

     // phi functions are also necessary for all locals stored in a subroutine

     scope()->requires_phi_function().set_union(block->stores_to_locals());

   }

   if (block->is_set(BlockBegin::parser_loop_header_flag)) {

     int header_loop_state = _loop_map.at(block_id);

     assert(is_power_of_2((unsigned)header_loop_state), "exactly one bit must be set");

     // If the highest bit is set (i.e. when integer value is negative), the method

     // has 32 or more loops. This bit is never cleared because it is used for multiple loops

     if (header_loop_state >= 0) {

       clear_bits(loop_state, header_loop_state);

     }

   }

   // cache and return loop information for this block

   _loop_map.at_put(block_id, loop_state);

   return loop_state;

 }

 #ifndef PRODUCT

 int compare_depth_first(BlockBegin** a, BlockBegin** b) {

   return (*a)->depth_first_number() - (*b)->depth_first_number();

 }

 void BlockListBuilder::print() {

   tty->print("----- initial block list of BlockListBuilder for method ");

   method()->print_short_name();

   tty->cr();

   // better readability if blocks are sorted in processing order

   _blocks.sort(compare_depth_first);

   for (int i = 0; i < _blocks.length(); i++) {

     BlockBegin* cur = _blocks.at(i);

     tty->print("%4d: B%-4d bci: %-4d  preds: %-4d ", cur->depth_first_number(), cur->block_id(), cur->bci(), cur->total_preds());

     tty->print(cur->is_set(BlockBegin::std_entry_flag)               ? " std" : "    ");

     tty->print(cur->is_set(BlockBegin::osr_entry_flag)               ? " osr" : "    ");

     tty->print(cur->is_set(BlockBegin::exception_entry_flag)         ? " ex" : "   ");

     tty->print(cur->is_set(BlockBegin::subroutine_entry_flag)        ? " sr" : "   ");

     tty->print(cur->is_set(BlockBegin::parser_loop_header_flag)      ? " lh" : "   ");

     if (cur->number_of_sux() > 0) {

       tty->print("    sux: ");

       for (int j = 0; j < cur->number_of_sux(); j++) {

         BlockBegin* sux = cur->sux_at(j);

         tty->print("B%d ", sux->block_id());

       }

     }

     tty->cr();

   }

 }

 #endif

 // A simple growable array of Values indexed by ciFields

 class FieldBuffer: public CompilationResourceObj {

  private:

   GrowableArray<Value> _values;

  public:

   FieldBuffer() {}

   void kill() {

     _values.trunc_to(0);

   }

   Value at(ciField* field) {

     assert(field->holder()->is_loaded(), "must be a loaded field");

     int offset = field->offset();

     if (offset < _values.length()) {

       return _values.at(offset);

     } else {

       return NULL;

     }

   }

   void at_put(ciField* field, Value value) {

     assert(field->holder()->is_loaded(), "must be a loaded field");

     int offset = field->offset();

     _values.at_put_grow(offset, value, NULL);

   }

 };

 // MemoryBuffer is fairly simple model of the current state of memory.

 // It partitions memory into several pieces.  The first piece is

 // generic memory where little is known about the owner of the memory.

 // This is conceptually represented by the tuple <O, F, V> which says

 // that the field F of object O has value V.  This is flattened so

 // that F is represented by the offset of the field and the parallel

 // arrays _objects and _values are used for O and V.  Loads of O.F can

 // simply use V.  Newly allocated objects are kept in a separate list

 // along with a parallel array for each object which represents the

 // current value of its fields.  Stores of the default value to fields

 // which have never been stored to before are eliminated since they

 // are redundant.  Once newly allocated objects are stored into

 // another object or they are passed out of the current compile they

 // are treated like generic memory.

 class MemoryBuffer: public CompilationResourceObj {

  private:

   FieldBuffer                 _values;

   GrowableArray<Value>        _objects;

   GrowableArray<Value>        _newobjects;

   GrowableArray<FieldBuffer*> _fields;

  public:

   MemoryBuffer() {}

   StoreField* store(StoreField* st) {

     if (!EliminateFieldAccess) {

       return st;

     }

     Value object = st->obj();

     Value value = st->value();

     ciField* field = st->field();

     if (field->holder()->is_loaded()) {

       int offset = field->offset();

       int index = _newobjects.find(object);

       if (index != -1) {

         // newly allocated object with no other stores performed on this field

         FieldBuffer* buf = _fields.at(index);

         if (buf->at(field) == NULL && is_default_value(value)) {

 #ifndef PRODUCT

           if (PrintIRDuringConstruction && Verbose) {

             tty->print_cr("Eliminated store for object %d:", index);

             st->print_line();

           }

 #endif

           return NULL;

         } else {

           buf->at_put(field, value);

         }

       } else {

         _objects.at_put_grow(offset, object, NULL);

         _values.at_put(field, value);

       }

       store_value(value);

     } else {

       // if we held onto field names we could alias based on names but

       // we don't know what's being stored to so kill it all.

       kill();

     }

     return st;

   }

   // return true if this value correspond to the default value of a field.

   bool is_default_value(Value value) {

     Constant* con = value->as_Constant();

     if (con) {

       switch (con->type()->tag()) {

         case intTag:    return con->type()->as_IntConstant()->value() == 0;

         case longTag:   return con->type()->as_LongConstant()->value() == 0;

         case floatTag:  return jint_cast(con->type()->as_FloatConstant()->value()) == 0;

         case doubleTag: return jlong_cast(con->type()->as_DoubleConstant()->value()) == jlong_cast(0);

         case objectTag: return con->type() == objectNull;

         default:  ShouldNotReachHere();

       }

     }

     return false;

   }

   // return either the actual value of a load or the load itself

   Value load(LoadField* load) {

     if (!EliminateFieldAccess) {

       return load;

     }

     if (RoundFPResults && UseSSE < 2 && load->type()->is_float_kind()) {

       // can't skip load since value might get rounded as a side effect

       return load;

     }

     ciField* field = load->field();

     Value object   = load->obj();

     if (field->holder()->is_loaded() && !field->is_volatile()) {

       int offset = field->offset();

       Value result = NULL;

       int index = _newobjects.find(object);

       if (index != -1) {

         result = _fields.at(index)->at(field);

       } else if (_objects.at_grow(offset, NULL) == object) {

         result = _values.at(field);

       }

       if (result != NULL) {

 #ifndef PRODUCT

         if (PrintIRDuringConstruction && Verbose) {

           tty->print_cr("Eliminated load: ");

           load->print_line();

         }

 #endif

         assert(result->type()->tag() == load->type()->tag(), "wrong types");

         return result;

       }

     }

     return load;

   }

   // Record this newly allocated object

   void new_instance(NewInstance* object) {

     int index = _newobjects.length();

     _newobjects.append(object);

     if (_fields.at_grow(index, NULL) == NULL) {

       _fields.at_put(index, new FieldBuffer());

     } else {

       _fields.at(index)->kill();

     }

   }

   void store_value(Value value) {

     int index = _newobjects.find(value);

     if (index != -1) {

       // stored a newly allocated object into another object.

       // Assume we've lost track of it as separate slice of memory.

       // We could do better by keeping track of whether individual

       // fields could alias each other.

       _newobjects.remove_at(index);

       // pull out the field info and store it at the end up the list

       // of field info list to be reused later.

       _fields.append(_fields.at(index));

       _fields.remove_at(index);

     }

   }

   void kill() {

     _newobjects.trunc_to(0);

     _objects.trunc_to(0);

     _values.kill();

   }

 };

 // Implementation of GraphBuilder's ScopeData

 GraphBuilder::ScopeData::ScopeData(ScopeData* parent)

   : _parent(parent)

   , _bci2block(NULL)

   , _scope(NULL)

   , _has_handler(false)

   , _stream(NULL)

   , _work_list(NULL)

   , _parsing_jsr(false)

   , _jsr_xhandlers(NULL)

   , _caller_stack_size(-1)

   , _continuation(NULL)

   , _num_returns(0)

   , _cleanup_block(NULL)

   , _cleanup_return_prev(NULL)

   , _cleanup_state(NULL)

 {

   if (parent != NULL) {

     _max_inline_size = (intx) ((float) NestedInliningSizeRatio * (float) parent->max_inline_size() / 100.0f);

   } else {

     _max_inline_size = MaxInlineSize;

   }

   if (_max_inline_size < MaxTrivialSize) {

     _max_inline_size = MaxTrivialSize;

   }

 }

 void GraphBuilder::kill_all() {

   if (UseLocalValueNumbering) {

     vmap()->kill_all();

   }

   _memory->kill();

 }

 BlockBegin* GraphBuilder::ScopeData::block_at(int bci) {

   if (parsing_jsr()) {

     // It is necessary to clone all blocks associated with a

     // subroutine, including those for exception handlers in the scope

     // of the method containing the jsr (because those exception

     // handlers may contain ret instructions in some cases).

     BlockBegin* block = bci2block()->at(bci);

     if (block != NULL && block == parent()->bci2block()->at(bci)) {

       BlockBegin* new_block = new BlockBegin(block->bci());

 #ifndef PRODUCT

       if (PrintInitialBlockList) {

         tty->print_cr("CFG: cloned block %d (bci %d) as block %d for jsr",

                       block->block_id(), block->bci(), new_block->block_id());

       }

 #endif

       // copy data from cloned blocked

       new_block->set_depth_first_number(block->depth_first_number());

       if (block->is_set(BlockBegin::parser_loop_header_flag)) new_block->set(BlockBegin::parser_loop_header_flag);

       // Preserve certain flags for assertion checking

       if (block->is_set(BlockBegin::subroutine_entry_flag)) new_block->set(BlockBegin::subroutine_entry_flag);

       if (block->is_set(BlockBegin::exception_entry_flag))  new_block->set(BlockBegin::exception_entry_flag);

       // copy was_visited_flag to allow early detection of bailouts

       // if a block that is used in a jsr has already been visited before,

       // it is shared between the normal control flow and a subroutine

       // BlockBegin::try_merge returns false when the flag is set, this leads

       // to a compilation bailout

       if (block->is_set(BlockBegin::was_visited_flag))  new_block->set(BlockBegin::was_visited_flag);

       bci2block()->at_put(bci, new_block);

       block = new_block;

     }

     return block;

   } else {

     return bci2block()->at(bci);

   }

 }

 XHandlers* GraphBuilder::ScopeData::xhandlers() const {

   if (_jsr_xhandlers == NULL) {

     assert(!parsing_jsr(), "");

     return scope()->xhandlers();

   }

   assert(parsing_jsr(), "");

   return _jsr_xhandlers;

 }

 void GraphBuilder::ScopeData::set_scope(IRScope* scope) {

   _scope = scope;

   bool parent_has_handler = false;

   if (parent() != NULL) {

     parent_has_handler = parent()->has_handler();

   }

   _has_handler = parent_has_handler || scope->xhandlers()->has_handlers();

 }

 void GraphBuilder::ScopeData::set_inline_cleanup_info(BlockBegin* block,

                                                       Instruction* return_prev,

                                                       ValueStack* return_state) {

   _cleanup_block       = block;

   _cleanup_return_prev = return_prev;

   _cleanup_state       = return_state;

 }

 void GraphBuilder::ScopeData::add_to_work_list(BlockBegin* block) {

   if (_work_list == NULL) {

     _work_list = new BlockList();

   }

   if (!block->is_set(BlockBegin::is_on_work_list_flag)) {

     // Do not start parsing the continuation block while in a

     // sub-scope

     if (parsing_jsr()) {

       if (block == jsr_continuation()) {

         return;

       }

     } else {

       if (block == continuation()) {

         return;

       }

     }

     block->set(BlockBegin::is_on_work_list_flag);

     _work_list->push(block);

     sort_top_into_worklist(_work_list, block);

   }

 }

 void GraphBuilder::sort_top_into_worklist(BlockList* worklist, BlockBegin* top) {

   assert(worklist->top() == top, "");

   // sort block descending into work list

   const int dfn = top->depth_first_number();

   assert(dfn != -1, "unknown depth first number");

   int i = worklist->length()-2;

   while (i >= 0) {

     BlockBegin* b = worklist->at(i);

     if (b->depth_first_number() < dfn) {

       worklist->at_put(i+1, b);

     } else {

       break;

     }

     i --;

   }

   if (i >= -1) worklist->at_put(i + 1, top);

 }

 BlockBegin* GraphBuilder::ScopeData::remove_from_work_list() {

   if (is_work_list_empty()) {

     return NULL;

   }

   return _work_list->pop();

 }

 bool GraphBuilder::ScopeData::is_work_list_empty() const {

   return (_work_list == NULL || _work_list->length() == 0);

 }

 void GraphBuilder::ScopeData::setup_jsr_xhandlers() {

   assert(parsing_jsr(), "");

   // clone all the exception handlers from the scope

   XHandlers* handlers = new XHandlers(scope()->xhandlers());

   const int n = handlers->length();

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

     // The XHandlers need to be adjusted to dispatch to the cloned

     // handler block instead of the default one but the synthetic

     // unlocker needs to be handled specially.  The synthetic unlocker

     // should be left alone since there can be only one and all code

     // should dispatch to the same one.

     XHandler* h = handlers->handler_at(i);

     assert(h->handler_bci() != SynchronizationEntryBCI, "must be real");

     h->set_entry_block(block_at(h->handler_bci()));

   }

   _jsr_xhandlers = handlers;

 }

 int GraphBuilder::ScopeData::num_returns() {

   if (parsing_jsr()) {

     return parent()->num_returns();

   }

   return _num_returns;

 }

 void GraphBuilder::ScopeData::incr_num_returns() {

   if (parsing_jsr()) {

     parent()->incr_num_returns();

   } else {

     ++_num_returns;

   }

 }

 // Implementation of GraphBuilder

 #define INLINE_BAILOUT(msg)        { inline_bailout(msg); return false; }

 void GraphBuilder::load_constant() {

   ciConstant con = stream()->get_constant();

   if (con.basic_type() == T_ILLEGAL) {

     BAILOUT("could not resolve a constant");

   } else {

     ValueType* t = illegalType;

     ValueStack* patch_state = NULL;

     switch (con.basic_type()) {

       case T_BOOLEAN: t = new IntConstant     (con.as_boolean()); break;

       case T_BYTE   : t = new IntConstant     (con.as_byte   ()); break;

       case T_CHAR   : t = new IntConstant     (con.as_char   ()); break;

       case T_SHORT  : t = new IntConstant     (con.as_short  ()); break;

       case T_INT    : t = new IntConstant     (con.as_int    ()); break;

       case T_LONG   : t = new LongConstant    (con.as_long   ()); break;

       case T_FLOAT  : t = new FloatConstant   (con.as_float  ()); break;

       case T_DOUBLE : t = new DoubleConstant  (con.as_double ()); break;

       case T_ARRAY  : t = new ArrayConstant   (con.as_object ()->as_array   ()); break;

       case T_OBJECT :

        {

         ciObject* obj = con.as_object();

         if (!obj->is_loaded()

             || (PatchALot && obj->klass() != ciEnv::current()->String_klass())) {

           patch_state = copy_state_before();

           t = new ObjectConstant(obj);

         } else {

           assert(!obj->is_klass(), "must be java_mirror of klass");

           t = new InstanceConstant(obj->as_instance());

         }

         break;

        }

       default       : ShouldNotReachHere();

     }

     Value x;

     if (patch_state != NULL) {

       x = new Constant(t, patch_state);

     } else {

       x = new Constant(t);

     }

     push(t, append(x));

   }

 }

 void GraphBuilder::load_local(ValueType* type, int index) {

   Value x = state()->local_at(index);

   assert(x != NULL && !x->type()->is_illegal(), "access of illegal local variable");

   push(type, x);

 }

 void GraphBuilder::store_local(ValueType* type, int index) {

   Value x = pop(type);

   store_local(state(), x, type, index);

 }

 void GraphBuilder::store_local(ValueStack* state, Value x, ValueType* type, int index) {

   if (parsing_jsr()) {

     // We need to do additional tracking of the location of the return

     // address for jsrs since we don't handle arbitrary jsr/ret

     // constructs. Here we are figuring out in which circumstances we

     // need to bail out.

     if (x->type()->is_address()) {

       scope_data()->set_jsr_return_address_local(index);

       // Also check parent jsrs (if any) at this time to see whether

       // they are using this local. We don't handle skipping over a

       // ret.

       for (ScopeData* cur_scope_data = scope_data()->parent();

            cur_scope_data != NULL && cur_scope_data->parsing_jsr() && cur_scope_data->scope() == scope();

            cur_scope_data = cur_scope_data->parent()) {

         if (cur_scope_data->jsr_return_address_local() == index) {

           BAILOUT("subroutine overwrites return address from previous subroutine");

         }

       }

     } else if (index == scope_data()->jsr_return_address_local()) {

       scope_data()->set_jsr_return_address_local(-1);

     }

   }

   state->store_local(index, round_fp(x));

 }

 void GraphBuilder::load_indexed(BasicType type) {

   ValueStack* state_before = copy_state_for_exception();

   Value index = ipop();

   Value array = apop();

   Value length = NULL;

   if (CSEArrayLength ||

       (array->as_AccessField() && array->as_AccessField()->field()->is_constant()) ||

       (array->as_NewArray() && array->as_NewArray()->length() && array->as_NewArray()->length()->type()->is_constant())) {

     length = append(new ArrayLength(array, state_before));

   }

   push(as_ValueType(type), append(new LoadIndexed(array, index, length, type, state_before)));

 }

 void GraphBuilder::store_indexed(BasicType type) {

   ValueStack* state_before = copy_state_for_exception();

   Value value = pop(as_ValueType(type));

   Value index = ipop();

   Value array = apop();

   Value length = NULL;

   if (CSEArrayLength ||

       (array->as_AccessField() && array->as_AccessField()->field()->is_constant()) ||

       (array->as_NewArray() && array->as_NewArray()->length() && array->as_NewArray()->length()->type()->is_constant())) {

     length = append(new ArrayLength(array, state_before));

   }

   StoreIndexed* result = new StoreIndexed(array, index, length, type, value, state_before);

   append(result);

   _memory->store_value(value);

   if (type == T_OBJECT && is_profiling()) {

     // Note that we'd collect profile data in this method if we wanted it.

     compilation()->set_would_profile(true);

     if (profile_checkcasts()) {

       result->set_profiled_method(method());

       result->set_profiled_bci(bci());

       result->set_should_profile(true);

     }

   }

 }

 void GraphBuilder::stack_op(Bytecodes::Code code) {

   switch (code) {

     case Bytecodes::_pop:

       { state()->raw_pop();

       }

       break;

     case Bytecodes::_pop2:

       { state()->raw_pop();

         state()->raw_pop();

       }

       break;

     case Bytecodes::_dup:

       { Value w = state()->raw_pop();

         state()->raw_push(w);

         state()->raw_push(w);

       }

       break;

     case Bytecodes::_dup_x1:

       { Value w1 = state()->raw_pop();

         Value w2 = state()->raw_pop();

         state()->raw_push(w1);

         state()->raw_push(w2);

         state()->raw_push(w1);

       }

       break;

     case Bytecodes::_dup_x2:

       { Value w1 = state()->raw_pop();

         Value w2 = state()->raw_pop();

         Value w3 = state()->raw_pop();

         state()->raw_push(w1);

         state()->raw_push(w3);

         state()->raw_push(w2);

         state()->raw_push(w1);

       }

       break;

     case Bytecodes::_dup2:

       { Value w1 = state()->raw_pop();

         Value w2 = state()->raw_pop();

         state()->raw_push(w2);

         state()->raw_push(w1);

         state()->raw_push(w2);

         state()->raw_push(w1);

       }

       break;

     case Bytecodes::_dup2_x1:

       { Value w1 = state()->raw_pop();

         Value w2 = state()->raw_pop();

         Value w3 = state()->raw_pop();

         state()->raw_push(w2);

         state()->raw_push(w1);

         state()->raw_push(w3);

         state()->raw_push(w2);

         state()->raw_push(w1);

       }

       break;

     case Bytecodes::_dup2_x2:

       { Value w1 = state()->raw_pop();

         Value w2 = state()->raw_pop();

         Value w3 = state()->raw_pop();

         Value w4 = state()->raw_pop();

         state()->raw_push(w2);

         state()->raw_push(w1);

         state()->raw_push(w4);

         state()->raw_push(w3);

         state()->raw_push(w2);

         state()->raw_push(w1);

       }

       break;

     case Bytecodes::_swap:

       { Value w1 = state()->raw_pop();

         Value w2 = state()->raw_pop();

         state()->raw_push(w1);

         state()->raw_push(w2);

       }

       break;

     default:

       ShouldNotReachHere();

       break;

   }

 }

 void GraphBuilder::arithmetic_op(ValueType* type, Bytecodes::Code code, ValueStack* state_before) {

   Value y = pop(type);

   Value x = pop(type);

   // NOTE: strictfp can be queried from current method since we don't

   // inline methods with differing strictfp bits

   Value res = new ArithmeticOp(code, x, y, method()->is_strict(), state_before);

   // Note: currently single-precision floating-point rounding on Intel is handled at the LIRGenerator level

   res = append(res);

   if (method()->is_strict()) {

     res = round_fp(res);

   }

   push(type, res);

 }

 void GraphBuilder::negate_op(ValueType* type) {

   push(type, append(new NegateOp(pop(type))));

 }

 void GraphBuilder::shift_op(ValueType* type, Bytecodes::Code code) {

   Value s = ipop();

   Value x = pop(type);

   // try to simplify

   // Note: This code should go into the canonicalizer as soon as it can

   //       can handle canonicalized forms that contain more than one node.

   if (CanonicalizeNodes && code == Bytecodes::_iushr) {

     // pattern: x >>> s

     IntConstant* s1 = s->type()->as_IntConstant();

     if (s1 != NULL) {

       // pattern: x >>> s1, with s1 constant

       ShiftOp* l = x->as_ShiftOp();

       if (l != NULL && l->op() == Bytecodes::_ishl) {

         // pattern: (a << b) >>> s1

         IntConstant* s0 = l->y()->type()->as_IntConstant();

         if (s0 != NULL) {

           // pattern: (a << s0) >>> s1

           const int s0c = s0->value() & 0x1F; // only the low 5 bits are significant for shifts

           const int s1c = s1->value() & 0x1F; // only the low 5 bits are significant for shifts

           if (s0c == s1c) {

             if (s0c == 0) {

               // pattern: (a << 0) >>> 0 => simplify to: a

               ipush(l->x());

             } else {

               // pattern: (a << s0c) >>> s0c => simplify to: a & m, with m constant

               assert(0 < s0c && s0c < BitsPerInt, "adjust code below to handle corner cases");

               const int m = (1 << (BitsPerInt - s0c)) - 1;

               Value s = append(new Constant(new IntConstant(m)));

               ipush(append(new LogicOp(Bytecodes::_iand, l->x(), s)));

             }

             return;

           }

         }

       }

     }

   }

   // could not simplify

   push(type, append(new ShiftOp(code, x, s)));

 }

 void GraphBuilder::logic_op(ValueType* type, Bytecodes::Code code) {

   Value y = pop(type);

   Value x = pop(type);

   push(type, append(new LogicOp(code, x, y)));

 }

 void GraphBuilder::compare_op(ValueType* type, Bytecodes::Code code) {

   ValueStack* state_before = copy_state_before();

   Value y = pop(type);

   Value x = pop(type);

   ipush(append(new CompareOp(code, x, y, state_before)));

 }

 void GraphBuilder::convert(Bytecodes::Code op, BasicType from, BasicType to) {

   push(as_ValueType(to), append(new Convert(op, pop(as_ValueType(from)), as_ValueType(to))));

 }

 void GraphBuilder::increment() {

   int index = stream()->get_index();

   int delta = stream()->is_wide() ? (signed short)Bytes::get_Java_u2(stream()->cur_bcp() + 4) : (signed char)(stream()->cur_bcp()[2]);

   load_local(intType, index);

   ipush(append(new Constant(new IntConstant(delta))));

   arithmetic_op(intType, Bytecodes::_iadd);

   store_local(intType, index);

 }

 void GraphBuilder::_goto(int from_bci, int to_bci) {

   Goto *x = new Goto(block_at(to_bci), to_bci <= from_bci);

   if (is_profiling()) {

     compilation()->set_would_profile(true);

   }

   if (profile_branches()) {

     x->set_profiled_method(method());

     x->set_profiled_bci(bci());

     x->set_should_profile(true);

   }

   append(x);

 }

 void GraphBuilder::if_node(Value x, If::Condition cond, Value y, ValueStack* state_before) {

   BlockBegin* tsux = block_at(stream()->get_dest());

   BlockBegin* fsux = block_at(stream()->next_bci());

   bool is_bb = tsux->bci() < stream()->cur_bci() || fsux->bci() < stream()->cur_bci();

   Instruction *i = append(new If(x, cond, false, y, tsux, fsux, is_bb ? state_before : NULL, is_bb));

   if (is_profiling()) {

     If* if_node = i->as_If();

     if (if_node != NULL) {

       // Note that we'd collect profile data in this method if we wanted it.

       compilation()->set_would_profile(true);

       // At level 2 we need the proper bci to count backedges

       if_node->set_profiled_bci(bci());

       if (profile_branches()) {

         // Successors can be rotated by the canonicalizer, check for this case.

         if_node->set_profiled_method(method());

         if_node->set_should_profile(true);

         if (if_node->tsux() == fsux) {

           if_node->set_swapped(true);

         }

       }

       return;

     }

     // Check if this If was reduced to Goto.

     Goto *goto_node = i->as_Goto();

     if (goto_node != NULL) {

       compilation()->set_would_profile(true);

       if (profile_branches()) {

         goto_node->set_profiled_method(method());

         goto_node->set_profiled_bci(bci());

         goto_node->set_should_profile(true);

         // Find out which successor is used.

         if (goto_node->default_sux() == tsux) {

           goto_node->set_direction(Goto::taken);

         } else if (goto_node->default_sux() == fsux) {

           goto_node->set_direction(Goto::not_taken);

         } else {

           ShouldNotReachHere();

         }

       }

       return;

     }

   }

 }

 void GraphBuilder::if_zero(ValueType* type, If::Condition cond) {

   Value y = append(new Constant(intZero));

   ValueStack* state_before = copy_state_before();

   Value x = ipop();

   if_node(x, cond, y, state_before);

 }

 void GraphBuilder::if_null(ValueType* type, If::Condition cond) {

   Value y = append(new Constant(objectNull));

   ValueStack* state_before = copy_state_before();

   Value x = apop();

   if_node(x, cond, y, state_before);

 }

 void GraphBuilder::if_same(ValueType* type, If::Condition cond) {

   ValueStack* state_before = copy_state_before();

   Value y = pop(type);

   Value x = pop(type);

   if_node(x, cond, y, state_before);

 }

 void GraphBuilder::jsr(int dest) {

   // We only handle well-formed jsrs (those which are "block-structured").

   // If the bytecodes are strange (jumping out of a jsr block) then we

   // might end up trying to re-parse a block containing a jsr which

   // has already been activated. Watch for this case and bail out.

   for (ScopeData* cur_scope_data = scope_data();

        cur_scope_data != NULL && cur_scope_data->parsing_jsr() && cur_scope_data->scope() == scope();

        cur_scope_data = cur_scope_data->parent()) {

     if (cur_scope_data->jsr_entry_bci() == dest) {

       BAILOUT("too-complicated jsr/ret structure");

     }

   }

   push(addressType, append(new Constant(new AddressConstant(next_bci()))));

   if (!try_inline_jsr(dest)) {

     return; // bailed out while parsing and inlining subroutine

   }

 }

 void GraphBuilder::ret(int local_index) {

   if (!parsing_jsr()) BAILOUT("ret encountered while not parsing subroutine");

   if (local_index != scope_data()->jsr_return_address_local()) {

     BAILOUT("can not handle complicated jsr/ret constructs");

   }

   // Rets simply become (NON-SAFEPOINT) gotos to the jsr continuation

   append(new Goto(scope_data()->jsr_continuation(), false));

 }

 void GraphBuilder::table_switch() {

   Bytecode_tableswitch sw(stream());

   const int l = sw.length();

   if (CanonicalizeNodes && l == 1) {

     // total of 2 successors => use If instead of switch

     // Note: This code should go into the canonicalizer as soon as it can

     //       can handle canonicalized forms that contain more than one node.

     Value key = append(new Constant(new IntConstant(sw.low_key())));

     BlockBegin* tsux = block_at(bci() + sw.dest_offset_at(0));

     BlockBegin* fsux = block_at(bci() + sw.default_offset());

     bool is_bb = tsux->bci() < bci() || fsux->bci() < bci();

     ValueStack* state_before = is_bb ? copy_state_before() : NULL;

     append(new If(ipop(), If::eql, true, key, tsux, fsux, state_before, is_bb));

   } else {

     // collect successors

     BlockList* sux = new BlockList(l + 1, NULL);

     int i;

     bool has_bb = false;

     for (i = 0; i < l; i++) {

       sux->at_put(i, block_at(bci() + sw.dest_offset_at(i)));

       if (sw.dest_offset_at(i) < 0) has_bb = true;

     }

     // add default successor

     sux->at_put(i, block_at(bci() + sw.default_offset()));

     ValueStack* state_before = has_bb ? copy_state_before() : NULL;

     append(new TableSwitch(ipop(), sux, sw.low_key(), state_before, has_bb));

   }

 }

 void GraphBuilder::lookup_switch() {

   Bytecode_lookupswitch sw(stream());

   const int l = sw.number_of_pairs();

   if (CanonicalizeNodes && l == 1) {

     // total of 2 successors => use If instead of switch

     // Note: This code should go into the canonicalizer as soon as it can

     //       can handle canonicalized forms that contain more than one node.

     // simplify to If

     LookupswitchPair pair = sw.pair_at(0);

     Value key = append(new Constant(new IntConstant(pair.match())));

     BlockBegin* tsux = block_at(bci() + pair.offset());

     BlockBegin* fsux = block_at(bci() + sw.default_offset());

     bool is_bb = tsux->bci() < bci() || fsux->bci() < bci();

     ValueStack* state_before = is_bb ? copy_state_before() : NULL;

     append(new If(ipop(), If::eql, true, key, tsux, fsux, state_before, is_bb));

   } else {

     // collect successors & keys

     BlockList* sux = new BlockList(l + 1, NULL);

     intArray* keys = new intArray(l, 0);

     int i;

     bool has_bb = false;

     for (i = 0; i < l; i++) {

       LookupswitchPair pair = sw.pair_at(i);

       if (pair.offset() < 0) has_bb = true;

       sux->at_put(i, block_at(bci() + pair.offset()));

       keys->at_put(i, pair.match());

     }

     // add default successor

     sux->at_put(i, block_at(bci() + sw.default_offset()));

     ValueStack* state_before = has_bb ? copy_state_before() : NULL;

     append(new LookupSwitch(ipop(), sux, keys, state_before, has_bb));

   }

 }

 void GraphBuilder::call_register_finalizer() {

   // If the receiver requires finalization then emit code to perform

   // the registration on return.

   // Gather some type information about the receiver

   Value receiver = state()->local_at(0);

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

   ciType* declared_type = receiver->declared_type();

   ciType* exact_type = receiver->exact_type();

   if (exact_type == NULL &&

       receiver->as_Local() &&

       receiver->as_Local()->java_index() == 0) {

     ciInstanceKlass* ik = compilation()->method()->holder();

     if (ik->is_final()) {

       exact_type = ik;

     } else if (UseCHA && !(ik->has_subklass() || ik->is_interface())) {

       // test class is leaf class

       compilation()->dependency_recorder()->assert_leaf_type(ik);

       exact_type = ik;

     } else {

       declared_type = ik;

     }

   }

   // see if we know statically that registration isn't required

   bool needs_check = true;

   if (exact_type != NULL) {

     needs_check = exact_type->as_instance_klass()->has_finalizer();

   } else if (declared_type != NULL) {

     ciInstanceKlass* ik = declared_type->as_instance_klass();

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

       compilation()->dependency_recorder()->assert_has_no_finalizable_subclasses(ik);

       needs_check = false;

     }

   }

   if (needs_check) {

     // Perform the registration of finalizable objects.

     ValueStack* state_before = copy_state_for_exception();

     load_local(objectType, 0);

     append_split(new Intrinsic(voidType, vmIntrinsics::_Object_init,

                                state()->pop_arguments(1),

                                true, state_before, true));

   }

 }

 void GraphBuilder::method_return(Value x) {

   if (RegisterFinalizersAtInit &&

       method()->intrinsic_id() == vmIntrinsics::_Object_init) {

     call_register_finalizer();

   }

   // Check to see whether we are inlining. If so, Return

   // instructions become Gotos to the continuation point.

   if (continuation() != NULL) {

     assert(!method()->is_synchronized() || InlineSynchronizedMethods, "can not inline synchronized methods yet");

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

       // Report exit from inline methods

       Values* args = new Values(1);

       args->push(append(new Constant(new ObjectConstant(method()))));

       append(new RuntimeCall(voidType, "dtrace_method_exit", CAST_FROM_FN_PTR(address, SharedRuntime::dtrace_method_exit), args));

     }

     // If the inlined method is synchronized, the monitor must be

     // released before we jump to the continuation block.

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

       assert(state()->locks_size() == 1, "receiver must be locked here");

       monitorexit(state()->lock_at(0), SynchronizationEntryBCI);

     }

     // State at end of inlined method is the state of the caller

     // without the method parameters on stack, including the

     // return value, if any, of the inlined method on operand stack.

     set_state(state()->caller_state()->copy_for_parsing());

     if (x != NULL) {

       state()->push(x->type(), x);

     }

     Goto* goto_callee = new Goto(continuation(), false);

     // See whether this is the first return; if so, store off some

     // of the state for later examination

     if (num_returns() == 0) {

       set_inline_cleanup_info(_block, _last, state());

     }

     // The current bci() is in the wrong scope, so use the bci() of

     // the continuation point.

     append_with_bci(goto_callee, scope_data()->continuation()->bci());

     incr_num_returns();

     return;

   }

   state()->truncate_stack(0);

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

     // perform the unlocking before exiting the method

     Value receiver;

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

       receiver = _initial_state->local_at(0);

     } else {

       receiver = append(new Constant(new ClassConstant(method()->holder())));

     }

     append_split(new MonitorExit(receiver, state()->unlock()));

   }

   append(new Return(x));

 }

 void GraphBuilder::access_field(Bytecodes::Code code) {

   bool will_link;

   ciField* field = stream()->get_field(will_link);

   ciInstanceKlass* holder = field->holder();

   BasicType field_type = field->type()->basic_type();

   ValueType* type = as_ValueType(field_type);

   // call will_link again to determine if the field is valid.

   const bool needs_patching = !holder->is_loaded() ||

                               !field->will_link(method()->holder(), code) ||

                               PatchALot;

   ValueStack* state_before = NULL;

   if (!holder->is_initialized() || needs_patching) {

     // save state before instruction for debug info when

     // deoptimization happens during patching

     state_before = copy_state_before();

   }

   Value obj = NULL;

   if (code == Bytecodes::_getstatic || code == Bytecodes::_putstatic) {

     if (state_before != NULL) {

       // build a patching constant

       obj = new Constant(new InstanceConstant(holder->java_mirror()), state_before);

     } else {

       obj = new Constant(new InstanceConstant(holder->java_mirror()));

     }

   }

   const int offset = !needs_patching ? field->offset() : -1;

   switch (code) {

     case Bytecodes::_getstatic: {

       // check for compile-time constants, i.e., initialized static final fields

       Instruction* constant = NULL;

       if (field->is_constant() && !PatchALot) {

         ciConstant field_val = field->constant_value();

         BasicType field_type = field_val.basic_type();

         switch (field_type) {

         case T_ARRAY:

         case T_OBJECT:

           if (field_val.as_object()->should_be_constant()) {

             constant =  new Constant(as_ValueType(field_val));

           }

           break;

         default:

           constant = new Constant(as_ValueType(field_val));

         }

       }

       if (constant != NULL) {

         push(type, append(constant));

       } else {

         if (state_before == NULL) {

           state_before = copy_state_for_exception();

         }

         push(type, append(new LoadField(append(obj), offset, field, true,

                                         state_before, needs_patching)));

       }

       break;

     }

     case Bytecodes::_putstatic:

       { Value val = pop(type);

         if (state_before == NULL) {

           state_before = copy_state_for_exception();

         }

         append(new StoreField(append(obj), offset, field, val, true, state_before, needs_patching));

       }

       break;

     case Bytecodes::_getfield :

       {

         if (state_before == NULL) {

           state_before = copy_state_for_exception();

         }

         LoadField* load = new LoadField(apop(), offset, field, false, state_before, needs_patching);

         Value replacement = !needs_patching ? _memory->load(load) : load;

         if (replacement != load) {

           assert(replacement->is_linked() || !replacement->can_be_linked(), "should already by linked");

           push(type, replacement);

         } else {

           push(type, append(load));

         }

         break;

       }

     case Bytecodes::_putfield :

       { Value val = pop(type);

         if (state_before == NULL) {

           state_before = copy_state_for_exception();

         }

         StoreField* store = new StoreField(apop(), offset, field, val, false, state_before, needs_patching);

         if (!needs_patching) store = _memory->store(store);

         if (store != NULL) {

           append(store);

         }

       }

       break;

     default                   :

       ShouldNotReachHere();

       break;

   }

 }

 Dependencies* GraphBuilder::dependency_recorder() const {

   assert(DeoptC1, "need debug information");

   return compilation()->dependency_recorder();

 }

 void GraphBuilder::invoke(Bytecodes::Code code) {

   bool will_link;

   ciMethod* target = stream()->get_method(will_link);

   // we have to make sure the argument size (incl. the receiver)

   // is correct for compilation (the call would fail later during

   // linkage anyway) - was bug (gri 7/28/99)

   if (target->is_loaded() && target->is_static() != (code == Bytecodes::_invokestatic)) BAILOUT("will cause link error");

   ciInstanceKlass* klass = target->holder();

   // check if CHA possible: if so, change the code to invoke_special

   ciInstanceKlass* calling_klass = method()->holder();

   ciKlass* holder = stream()->get_declared_method_holder();

   ciInstanceKlass* callee_holder = ciEnv::get_instance_klass_for_declared_method_holder(holder);

   ciInstanceKlass* actual_recv = callee_holder;

   // some methods are obviously bindable without any type checks so

   // convert them directly to an invokespecial.

   if (target->is_loaded() && !target->is_abstract() &&

       target->can_be_statically_bound() && code == Bytecodes::_invokevirtual) {

     code = Bytecodes::_invokespecial;

   }

   // NEEDS_CLEANUP

   // I've added the target-is_loaded() test below but I don't really understand

   // how klass->is_loaded() can be true and yet target->is_loaded() is false.

   // this happened while running the JCK invokevirtual tests under doit.  TKR

   ciMethod* cha_monomorphic_target = NULL;

   ciMethod* exact_target = NULL;

   if (UseCHA && DeoptC1 && klass->is_loaded() && target->is_loaded() &&

       !target->is_method_handle_invoke()) {

     Value receiver = NULL;

     ciInstanceKlass* receiver_klass = NULL;

     bool type_is_exact = false;

     // try to find a precise receiver type

     if (will_link && !target->is_static()) {

       int index = state()->stack_size() - (target->arg_size_no_receiver() + 1);

       receiver = state()->stack_at(index);

       ciType* type = receiver->exact_type();

       if (type != NULL && type->is_loaded() &&

           type->is_instance_klass() && !type->as_instance_klass()->is_interface()) {

         receiver_klass = (ciInstanceKlass*) type;

         type_is_exact = true;

       }

       if (type == NULL) {

         type = receiver->declared_type();

         if (type != NULL && type->is_loaded() &&

             type->is_instance_klass() && !type->as_instance_klass()->is_interface()) {

           receiver_klass = (ciInstanceKlass*) type;

           if (receiver_klass->is_leaf_type() && !receiver_klass->is_final()) {

             // Insert a dependency on this type since

             // find_monomorphic_target may assume it's already done.

             dependency_recorder()->assert_leaf_type(receiver_klass);

             type_is_exact = true;

           }

         }

       }

     }

     if (receiver_klass != NULL && type_is_exact &&

         receiver_klass->is_loaded() && code != Bytecodes::_invokespecial) {

       // If we have the exact receiver type we can bind directly to

       // the method to call.

       exact_target = target->resolve_invoke(calling_klass, receiver_klass);

       if (exact_target != NULL) {

         target = exact_target;

         code = Bytecodes::_invokespecial;

       }

     }

     if (receiver_klass != NULL &&

         receiver_klass->is_subtype_of(actual_recv) &&

         actual_recv->is_initialized()) {

       actual_recv = receiver_klass;

     }

     if ((code == Bytecodes::_invokevirtual && callee_holder->is_initialized()) ||

         (code == Bytecodes::_invokeinterface && callee_holder->is_initialized() && !actual_recv->is_interface())) {

       // Use CHA on the receiver to select a more precise method.

       cha_monomorphic_target = target->find_monomorphic_target(calling_klass, callee_holder, actual_recv);

     } else if (code == Bytecodes::_invokeinterface && callee_holder->is_loaded() && receiver != NULL) {

       // if there is only one implementor of this interface then we

       // may be able bind this invoke directly to the implementing

       // klass but we need both a dependence on the single interface

       // and on the method we bind to.  Additionally since all we know

       // about the receiver type is the it's supposed to implement the

       // interface we have to insert a check that it's the class we

       // expect.  Interface types are not checked by the verifier so

       // they are roughly equivalent to Object.

       ciInstanceKlass* singleton = NULL;

       if (target->holder()->nof_implementors() == 1) {

         singleton = target->holder()->implementor(0);

       }

       if (singleton) {

         cha_monomorphic_target = target->find_monomorphic_target(calling_klass, target->holder(), singleton);

         if (cha_monomorphic_target != NULL) {

           // If CHA is able to bind this invoke then update the class

           // to match that class, otherwise klass will refer to the

           // interface.

           klass = cha_monomorphic_target->holder();

           actual_recv = target->holder();

           // insert a check it's really the expected class.

           CheckCast* c = new CheckCast(klass, receiver, copy_state_for_exception());

           c->set_incompatible_class_change_check();

           c->set_direct_compare(klass->is_final());

           append_split(c);

         }

       }

     }

   }

   if (cha_monomorphic_target != NULL) {

     if (cha_monomorphic_target->is_abstract()) {

       // Do not optimize for abstract methods

       cha_monomorphic_target = NULL;

     }

   }

   if (cha_monomorphic_target != NULL) {

     if (!(target->is_final_method())) {

       // If we inlined because CHA revealed only a single target method,

       // then we are dependent on that target method not getting overridden

       // by dynamic class loading.  Be sure to test the "static" receiver

       // dest_method here, as opposed to the actual receiver, which may

       // falsely lead us to believe that the receiver is final or private.

       dependency_recorder()->assert_unique_concrete_method(actual_recv, cha_monomorphic_target);

     }

     code = Bytecodes::_invokespecial;

   }

   // check if we could do inlining

   if (!PatchALot && Inline && klass->is_loaded() &&

       (klass->is_initialized() || klass->is_interface() && target->holder()->is_initialized())

       && target->will_link(klass, callee_holder, code)) {

     // callee is known => check if we have static binding

     assert(target->is_loaded(), "callee must be known");

     if (code == Bytecodes::_invokestatic

      || code == Bytecodes::_invokespecial

      || code == Bytecodes::_invokevirtual && target->is_final_method()

     ) {

       // static binding => check if callee is ok

       ciMethod* inline_target = (cha_monomorphic_target != NULL)

                                   ? cha_monomorphic_target

                                   : target;

       bool res = try_inline(inline_target, (cha_monomorphic_target != NULL) || (exact_target != NULL));

       CHECK_BAILOUT();

 #ifndef PRODUCT

       // printing

       if (PrintInlining && !res) {

         // if it was successfully inlined, then it was already printed.

         print_inline_result(inline_target, res);

       }

 #endif

       clear_inline_bailout();

       if (res) {

         // Register dependence if JVMTI has either breakpoint

         // setting or hotswapping of methods capabilities since they may

         // cause deoptimization.

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

           dependency_recorder()->assert_evol_method(inline_target);

         }

         return;

       }

     }

   }

   // If we attempted an inline which did not succeed because of a

   // bailout during construction of the callee graph, the entire

   // compilation has to be aborted. This is fairly rare and currently

   // seems to only occur for jasm-generated classes which contain

   // jsr/ret pairs which are not associated with finally clauses and

   // do not have exception handlers in the containing method, and are

   // therefore not caught early enough to abort the inlining without

   // corrupting the graph. (We currently bail out with a non-empty

   // stack at a ret in these situations.)

   CHECK_BAILOUT();

   // inlining not successful => standard invoke

   bool is_loaded = target->is_loaded();

   bool has_receiver =

     code == Bytecodes::_invokespecial   ||

     code == Bytecodes::_invokevirtual   ||

     code == Bytecodes::_invokeinterface;

   bool is_invokedynamic = code == Bytecodes::_invokedynamic;

   ValueType* result_type = as_ValueType(target->return_type());

   // We require the debug info to be the "state before" because

   // invokedynamics may deoptimize.

   ValueStack* state_before = is_invokedynamic ? copy_state_before() : copy_state_exhandling();

   Values* args = state()->pop_arguments(target->arg_size_no_receiver());

   Value recv = has_receiver ? apop() : NULL;

   int vtable_index = methodOopDesc::invalid_vtable_index;

 #ifdef SPARC

   // Currently only supported on Sparc.

   // The UseInlineCaches only controls dispatch to invokevirtuals for

   // loaded classes which we weren't able to statically bind.

   if (!UseInlineCaches && is_loaded && code == Bytecodes::_invokevirtual

       && !target->can_be_statically_bound()) {

     // Find a vtable index if one is available

     vtable_index = target->resolve_vtable_index(calling_klass, callee_holder);

   }

 #endif

   if (recv != NULL &&

       (code == Bytecodes::_invokespecial ||

        !is_loaded || target->is_final())) {

     // invokespecial always needs a NULL check.  invokevirtual where

     // the target is final or where it's not known that whether the

     // target is final requires a NULL check.  Otherwise normal

     // invokevirtual will perform the null check during the lookup

     // logic or the unverified entry point.  Profiling of calls

     // requires that the null check is performed in all cases.

     null_check(recv);

   }

   if (is_profiling()) {

     if (recv != NULL && profile_calls()) {

       null_check(recv);

     }

     // Note that we'd collect profile data in this method if we wanted it.

     compilation()->set_would_profile(true);

     if (profile_calls()) {

       assert(cha_monomorphic_target == NULL || exact_target == NULL, "both can not be set");

       ciKlass* target_klass = NULL;

       if (cha_monomorphic_target != NULL) {

         target_klass = cha_monomorphic_target->holder();

       } else if (exact_target != NULL) {

         target_klass = exact_target->holder();

       }

       profile_call(recv, target_klass);

     }

   }

   Invoke* result = new Invoke(code, result_type, recv, args, vtable_index, target, state_before);

   // push result

   append_split(result);

   if (result_type != voidType) {

     if (method()->is_strict()) {

       push(result_type, round_fp(result));

     } else {

       push(result_type, result);

     }

   }

 }

 void GraphBuilder::new_instance(int klass_index) {

   ValueStack* state_before = copy_state_exhandling();

   bool will_link;

   ciKlass* klass = stream()->get_klass(will_link);

   assert(klass->is_instance_klass(), "must be an instance klass");

   NewInstance* new_instance = new NewInstance(klass->as_instance_klass(), state_before);

   _memory->new_instance(new_instance);

   apush(append_split(new_instance));

 }

 void GraphBuilder::new_type_array() {

   ValueStack* state_before = copy_state_exhandling();

   apush(append_split(new NewTypeArray(ipop(), (BasicType)stream()->get_index(), state_before)));

 }

 void GraphBuilder::new_object_array() {

   bool will_link;

   ciKlass* klass = stream()->get_klass(will_link);

   ValueStack* state_before = !klass->is_loaded() || PatchALot ? copy_state_before() : copy_state_exhandling();

   NewArray* n = new NewObjectArray(klass, ipop(), state_before);

   apush(append_split(n));

 }

 bool GraphBuilder::direct_compare(ciKlass* k) {

   if (k->is_loaded() && k->is_instance_klass() && !UseSlowPath) {

     ciInstanceKlass* ik = k->as_instance_klass();

     if (ik->is_final()) {

       return true;

     } else {

       if (DeoptC1 && UseCHA && !(ik->has_subklass() || ik->is_interface())) {

         // test class is leaf class

         dependency_recorder()->assert_leaf_type(ik);

         return true;

       }

     }

   }

   return false;

 }

 void GraphBuilder::check_cast(int klass_index) {

   bool will_link;

   ciKlass* klass = stream()->get_klass(will_link);

   ValueStack* state_before = !klass->is_loaded() || PatchALot ? copy_state_before() : copy_state_for_exception();

   CheckCast* c = new CheckCast(klass, apop(), state_before);

   apush(append_split(c));

   c->set_direct_compare(direct_compare(klass));

   if (is_profiling()) {

     // Note that we'd collect profile data in this method if we wanted it.

     compilation()->set_would_profile(true);

     if (profile_checkcasts()) {

       c->set_profiled_method(method());

       c->set_profiled_bci(bci());

       c->set_should_profile(true);

     }

   }

 }

 void GraphBuilder::instance_of(int klass_index) {

   bool will_link;

   ciKlass* klass = stream()->get_klass(will_link);

   ValueStack* state_before = !klass->is_loaded() || PatchALot ? copy_state_before() : copy_state_exhandling();

   InstanceOf* i = new InstanceOf(klass, apop(), state_before);

   ipush(append_split(i));

   i->set_direct_compare(direct_compare(klass));

   if (is_profiling()) {

     // Note that we'd collect profile data in this method if we wanted it.

     compilation()->set_would_profile(true);

     if (profile_checkcasts()) {

       i->set_profiled_method(method());

       i->set_profiled_bci(bci());

       i->set_should_profile(true);

     }

   }

 }

 void GraphBuilder::monitorenter(Value x, int bci) {

   // save state before locking in case of deoptimization after a NullPointerException

   ValueStack* state_before = copy_state_for_exception_with_bci(bci);

   append_with_bci(new MonitorEnter(x, state()->lock(x), state_before), bci);

   kill_all();

 }

 void GraphBuilder::monitorexit(Value x, int bci) {

   append_with_bci(new MonitorExit(x, state()->unlock()), bci);

   kill_all();

 }

 void GraphBuilder::new_multi_array(int dimensions) {

   bool will_link;

   ciKlass* klass = stream()->get_klass(will_link);

   ValueStack* state_before = !klass->is_loaded() || PatchALot ? copy_state_before() : copy_state_exhandling();

   Values* dims = new Values(dimensions, NULL);

   // fill in all dimensions

   int i = dimensions;

   while (i-- > 0) dims->at_put(i, ipop());

   // create array

   NewArray* n = new NewMultiArray(klass, dims, state_before);

   apush(append_split(n));

 }

 void GraphBuilder::throw_op(int bci) {

   // We require that the debug info for a Throw be the "state before"

   // the Throw (i.e., exception oop is still on TOS)

   ValueStack* state_before = copy_state_before_with_bci(bci);

   Throw* t = new Throw(apop(), state_before);

   // operand stack not needed after a throw

   state()->truncate_stack(0);

   append_with_bci(t, bci);

 }

 Value GraphBuilder::round_fp(Value fp_value) {

   // no rounding needed if SSE2 is used

   if (RoundFPResults && UseSSE < 2) {

     // Must currently insert rounding node for doubleword values that

     // are results of expressions (i.e., not loads from memory or

     // constants)

     if (fp_value->type()->tag() == doubleTag &&

         fp_value->as_Constant() == NULL &&

         fp_value->as_Local() == NULL &&       // method parameters need no rounding

         fp_value->as_RoundFP() == NULL) {

       return append(new RoundFP(fp_value));

     }

   }

   return fp_value;

 }

 Instruction* GraphBuilder::append_with_bci(Instruction* instr, int bci) {

   Canonicalizer canon(compilation(), instr, bci);

   Instruction* i1 = canon.canonical();

   if (i1->is_linked() || !i1->can_be_linked()) {

     // Canonicalizer returned an instruction which was already

     // appended so simply return it.

     return i1;

   }

   if (UseLocalValueNumbering) {

     // Lookup the instruction in the ValueMap and add it to the map if

     // it's not found.

     Instruction* i2 = vmap()->find_insert(i1);

     if (i2 != i1) {

       // found an entry in the value map, so just return it.

       assert(i2->is_linked(), "should already be linked");

       return i2;

     }

     ValueNumberingEffects vne(vmap());

     i1->visit(&vne);

   }

   // i1 was not eliminated => append it

   assert(i1->next() == NULL, "shouldn't already be linked");

   _last = _last->set_next(i1, canon.bci());

   if (++_instruction_count >= InstructionCountCutoff && !bailed_out()) {

     // set the bailout state but complete normal processing.  We

     // might do a little more work before noticing the bailout so we

     // want processing to continue normally until it's noticed.

     bailout("Method and/or inlining is too large");

   }

 #ifndef PRODUCT

   if (PrintIRDuringConstruction) {

     InstructionPrinter ip;

     ip.print_line(i1);

     if (Verbose) {

       state()->print();

     }

   }

 #endif

   // save state after modification of operand stack for StateSplit instructions

   StateSplit* s = i1->as_StateSplit();

   if (s != NULL) {

     if (EliminateFieldAccess) {

       Intrinsic* intrinsic = s->as_Intrinsic();

       if (s->as_Invoke() != NULL || (intrinsic && !intrinsic->preserves_state())) {

         _memory->kill();

       }

     }

     s->set_state(state()->copy(ValueStack::StateAfter, canon.bci()));

   }

   // set up exception handlers for this instruction if necessary

   if (i1->can_trap()) {

     i1->set_exception_handlers(handle_exception(i1));

     assert(i1->exception_state() != NULL || !i1->needs_exception_state() || bailed_out(), "handle_exception must set exception state");

   }

   return i1;

 }

 Instruction* GraphBuilder::append(Instruction* instr) {

   assert(instr->as_StateSplit() == NULL || instr->as_BlockEnd() != NULL, "wrong append used");

   return append_with_bci(instr, bci());

 }

 Instruction* GraphBuilder::append_split(StateSplit* instr) {

   return append_with_bci(instr, bci());

 }

 void GraphBuilder::null_check(Value value) {

   if (value->as_NewArray() != NULL || value->as_NewInstance() != NULL) {

     return;

   } else {

     Constant* con = value->as_Constant();

     if (con) {

       ObjectType* c = con->type()->as_ObjectType();

       if (c && c->is_loaded()) {

         ObjectConstant* oc = c->as_ObjectConstant();

         if (!oc || !oc->value()->is_null_object()) {

           return;

         }

       }

     }

   }

   append(new NullCheck(value, copy_state_for_exception()));

 }

 XHandlers* GraphBuilder::handle_exception(Instruction* instruction) {

   if (!has_handler() && (!instruction->needs_exception_state() || instruction->exception_state() != NULL)) {

     assert(instruction->exception_state() == NULL

            || instruction->exception_state()->kind() == ValueStack::EmptyExceptionState

            || (instruction->exception_state()->kind() == ValueStack::ExceptionState && _compilation->env()->jvmti_can_access_local_variables()),

            "exception_state should be of exception kind");

     return new XHandlers();

   }

   XHandlers*  exception_handlers = new XHandlers();

   ScopeData*  cur_scope_data = scope_data();

   ValueStack* cur_state = instruction->state_before();

   ValueStack* prev_state = NULL;

   int scope_count = 0;

   assert(cur_state != NULL, "state_before must be set");

   do {

     int cur_bci = cur_state->bci();

     assert(cur_scope_data->scope() == cur_state->scope(), "scopes do not match");

     assert(cur_bci == SynchronizationEntryBCI || cur_bci == cur_scope_data->stream()->cur_bci(), "invalid bci");

     // join with all potential exception handlers

     XHandlers* list = cur_scope_data->xhandlers();

     const int n = list->length();

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

       XHandler* h = list->handler_at(i);

       if (h->covers(cur_bci)) {

         // h is a potential exception handler => join it

         compilation()->set_has_exception_handlers(true);

         BlockBegin* entry = h->entry_block();

         if (entry == block()) {

           // It's acceptable for an exception handler to cover itself

           // but we don't handle that in the parser currently.  It's

           // very rare so we bailout instead of trying to handle it.

           BAILOUT_("exception handler covers itself", exception_handlers);

         }

         assert(entry->bci() == h->handler_bci(), "must match");

         assert(entry->bci() == -1 || entry == cur_scope_data->block_at(entry->bci()), "blocks must correspond");

         // previously this was a BAILOUT, but this is not necessary

         // now because asynchronous exceptions are not handled this way.

         assert(entry->state() == NULL || cur_state->total_locks_size() == entry->state()->total_locks_size(), "locks do not match");

         // xhandler start with an empty expression stack

         if (cur_state->stack_size() != 0) {

           cur_state = cur_state->copy(ValueStack::ExceptionState, cur_state->bci());

         }

         if (instruction->exception_state() == NULL) {

           instruction->set_exception_state(cur_state);

         }

         // Note: Usually this join must work. However, very

         // complicated jsr-ret structures where we don't ret from

         // the subroutine can cause the objects on the monitor

         // stacks to not match because blocks can be parsed twice.

         // The only test case we've seen so far which exhibits this

         // problem is caught by the infinite recursion test in

         // GraphBuilder::jsr() if the join doesn't work.

         if (!entry->try_merge(cur_state)) {

           BAILOUT_("error while joining with exception handler, prob. due to complicated jsr/rets", exception_handlers);

         }

         // add current state for correct handling of phi functions at begin of xhandler

         int phi_operand = entry->add_exception_state(cur_state);

         // add entry to the list of xhandlers of this block

         _block->add_exception_handler(entry);

         // add back-edge from xhandler entry to this block

         if (!entry->is_predecessor(_block)) {

           entry->add_predecessor(_block);

         }

         // clone XHandler because phi_operand and scope_count can not be shared

         XHandler* new_xhandler = new XHandler(h);

         new_xhandler->set_phi_operand(phi_operand);

         new_xhandler->set_scope_count(scope_count);

         exception_handlers->append(new_xhandler);

         // fill in exception handler subgraph lazily

         assert(!entry->is_set(BlockBegin::was_visited_flag), "entry must not be visited yet");

         cur_scope_data->add_to_work_list(entry);

         // stop when reaching catchall

         if (h->catch_type() == 0) {

           return exception_handlers;

         }

       }

     }

     if (exception_handlers->length() == 0) {

       // This scope and all callees do not handle exceptions, so the local

       // variables of this scope are not needed. However, the scope itself is

       // required for a correct exception stack trace -> clear out the locals.

       if (_compilation->env()->jvmti_can_access_local_variables()) {

         cur_state = cur_state->copy(ValueStack::ExceptionState, cur_state->bci());

       } else {

         cur_state = cur_state->copy(ValueStack::EmptyExceptionState, cur_state->bci());

       }

       if (prev_state != NULL) {

         prev_state->set_caller_state(cur_state);

       }

       if (instruction->exception_state() == NULL) {

         instruction->set_exception_state(cur_state);

       }

     }

     // Set up iteration for next time.

     // If parsing a jsr, do not grab exception handlers from the

     // parent scopes for this method (already got them, and they

     // needed to be cloned)

     while (cur_scope_data->parsing_jsr()) {

       cur_scope_data = cur_scope_data->parent();

     }

     assert(cur_scope_data->scope() == cur_state->scope(), "scopes do not match");

     assert(cur_state->locks_size() == 0 || cur_state->locks_size() == 1, "unlocking must be done in a catchall exception handler");

     prev_state = cur_state;

     cur_state = cur_state->caller_state();

     cur_scope_data = cur_scope_data->parent();

     scope_count++;

   } while (cur_scope_data != NULL);

   return exception_handlers;

 }

 // Helper class for simplifying Phis.

 class PhiSimplifier : public BlockClosure {

  private:

   bool _has_substitutions;

   Value simplify(Value v);

  public:

   PhiSimplifier(BlockBegin* start) : _has_substitutions(false) {

     start->iterate_preorder(this);

     if (_has_substitutions) {

       SubstitutionResolver sr(start);

     }

   }

   void block_do(BlockBegin* b);

   bool has_substitutions() const { return _has_substitutions; }

 };

 Value PhiSimplifier::simplify(Value v) {

   Phi* phi = v->as_Phi();

   if (phi == NULL) {

     // no phi function

     return v;

   } else if (v->has_subst()) {

     // already substituted; subst can be phi itself -> simplify

     return simplify(v->subst());

   } else if (phi->is_set(Phi::cannot_simplify)) {

     // already tried to simplify phi before

     return phi;

   } else if (phi->is_set(Phi::visited)) {

     // break cycles in phi functions

     return phi;

   } else if (phi->type()->is_illegal()) {

     // illegal phi functions are ignored anyway

     return phi;

   } else {

     // mark phi function as processed to break cycles in phi functions

     phi->set(Phi::visited);

     // simplify x = [y, x] and x = [y, y] to y

     Value subst = NULL;

     int opd_count = phi->operand_count();

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

       Value opd = phi->operand_at(i);

       assert(opd != NULL, "Operand must exist!");

       if (opd->type()->is_illegal()) {

         // if one operand is illegal, the entire phi function is illegal

         phi->make_illegal();

         phi->clear(Phi::visited);

         return phi;

       }

       Value new_opd = simplify(opd);

       assert(new_opd != NULL, "Simplified operand must exist!");

       if (new_opd != phi && new_opd != subst) {

         if (subst == NULL) {

           subst = new_opd;

         } else {

           // no simplification possible

           phi->set(Phi::cannot_simplify);

           phi->clear(Phi::visited);

           return phi;

         }

       }

     }

     // sucessfully simplified phi function

     assert(subst != NULL, "illegal phi function");

     _has_substitutions = true;

     phi->clear(Phi::visited);

     phi->set_subst(subst);

 #ifndef PRODUCT

     if (PrintPhiFunctions) {

       tty->print_cr("simplified phi function %c%d to %c%d (Block B%d)", phi->type()->tchar(), phi->id(), subst->type()->tchar(), subst->id(), phi->block()->block_id());

     }

 #endif

     return subst;

   }

 }

 void PhiSimplifier::block_do(BlockBegin* b) {

   for_each_phi_fun(b, phi,

     simplify(phi);

   );

 #ifdef ASSERT

   for_each_phi_fun(b, phi,

                    assert(phi->operand_count() != 1 || phi->subst() != phi, "missed trivial simplification");

   );

   ValueStack* state = b->state()->caller_state();

   for_each_state_value(state, value,

     Phi* phi = value->as_Phi();

     assert(phi == NULL || phi->block() != b, "must not have phi function to simplify in caller state");

   );

 #endif

 }

 // This method is called after all blocks are filled with HIR instructions

 // It eliminates all Phi functions of the form x = [y, y] and x = [y, x]

 void GraphBuilder::eliminate_redundant_phis(BlockBegin* start) {

   PhiSimplifier simplifier(start);

 }

 void GraphBuilder::connect_to_end(BlockBegin* beg) {

   // setup iteration

   kill_all();

   _block = beg;

   _state = beg->state()->copy_for_parsing();

   _last  = beg;

   iterate_bytecodes_for_block(beg->bci());

 }

 BlockEnd* GraphBuilder::iterate_bytecodes_for_block(int bci) {

 #ifndef PRODUCT

   if (PrintIRDuringConstruction) {

     tty->cr();

     InstructionPrinter ip;

     ip.print_instr(_block); tty->cr();

     ip.print_stack(_block->state()); tty->cr();

     ip.print_inline_level(_block);

     ip.print_head();

     tty->print_cr("locals size: %d stack size: %d", state()->locals_size(), state()->stack_size());

   }

 #endif

   _skip_block = false;

   assert(state() != NULL, "ValueStack missing!");

   ciBytecodeStream s(method());

   s.reset_to_bci(bci);

   int prev_bci = bci;

   scope_data()->set_stream(&s);

   // iterate

   Bytecodes::Code code = Bytecodes::_illegal;

   bool push_exception = false;

   if (block()->is_set(BlockBegin::exception_entry_flag) && block()->next() == NULL) {

     // first thing in the exception entry block should be the exception object.

     push_exception = true;

   }

   while (!bailed_out() && last()->as_BlockEnd() == NULL &&

          (code = stream()->next()) != ciBytecodeStream::EOBC() &&

          (block_at(s.cur_bci()) == NULL || block_at(s.cur_bci()) == block())) {

     assert(state()->kind() == ValueStack::Parsing, "invalid state kind");

     // Check for active jsr during OSR compilation

     if (compilation()->is_osr_compile()

         && scope()->is_top_scope()

         && parsing_jsr()

         && s.cur_bci() == compilation()->osr_bci()) {

       bailout("OSR not supported while a jsr is active");

     }

     if (push_exception) {

       apush(append(new ExceptionObject()));

       push_exception = false;

     }

     // handle bytecode

     switch (code) {

       case Bytecodes::_nop            : /* nothing to do */ break;

       case Bytecodes::_aconst_null    : apush(append(new Constant(objectNull            ))); break;

       case Bytecodes::_iconst_m1      : ipush(append(new Constant(new IntConstant   (-1)))); break;

       case Bytecodes::_iconst_0       : ipush(append(new Constant(intZero               ))); break;

       case Bytecodes::_iconst_1       : ipush(append(new Constant(intOne                ))); break;

       case Bytecodes::_iconst_2       : ipush(append(new Constant(new IntConstant   ( 2)))); break;

       case Bytecodes::_iconst_3       : ipush(append(new Constant(new IntConstant   ( 3)))); break;

       case Bytecodes::_iconst_4       : ipush(append(new Constant(new IntConstant   ( 4)))); break;

       case Bytecodes::_iconst_5       : ipush(append(new Constant(new IntConstant   ( 5)))); break;

       case Bytecodes::_lconst_0       : lpush(append(new Constant(new LongConstant  ( 0)))); break;

       case Bytecodes::_lconst_1       : lpush(append(new Constant(new LongConstant  ( 1)))); break;

       case Bytecodes::_fconst_0       : fpush(append(new Constant(new FloatConstant ( 0)))); break;

       case Bytecodes::_fconst_1       : fpush(append(new Constant(new FloatConstant ( 1)))); break;

       case Bytecodes::_fconst_2       : fpush(append(new Constant(new FloatConstant ( 2)))); break;

       case Bytecodes::_dconst_0       : dpush(append(new Constant(new DoubleConstant( 0)))); break;

       case Bytecodes::_dconst_1       : dpush(append(new Constant(new DoubleConstant( 1)))); break;

       case Bytecodes::_bipush         : ipush(append(new Constant(new IntConstant(((signed char*)s.cur_bcp())[1])))); break;

       case Bytecodes::_sipush         : ipush(append(new Constant(new IntConstant((short)Bytes::get_Java_u2(s.cur_bcp()+1))))); break;

       case Bytecodes::_ldc            : // fall through

       case Bytecodes::_ldc_w          : // fall through

       case Bytecodes::_ldc2_w         : load_constant(); break;

       case Bytecodes::_iload          : load_local(intType     , s.get_index()); break;

       case Bytecodes::_lload          : load_local(longType    , s.get_index()); break;

       case Bytecodes::_fload          : load_local(floatType   , s.get_index()); break;

       case Bytecodes::_dload          : load_local(doubleType  , s.get_index()); break;

       case Bytecodes::_aload          : load_local(instanceType, s.get_index()); break;

       case Bytecodes::_iload_0        : load_local(intType   , 0); break;

       case Bytecodes::_iload_1        : load_local(intType   , 1); break;

       case Bytecodes::_iload_2        : load_local(intType   , 2); break;

       case Bytecodes::_iload_3        : load_local(intType   , 3); break;

       case Bytecodes::_lload_0        : load_local(longType  , 0); break;

       case Bytecodes::_lload_1        : load_local(longType  , 1); break;

       case Bytecodes::_lload_2        : load_local(longType  , 2); break;

       case Bytecodes::_lload_3        : load_local(longType  , 3); break;

       case Bytecodes::_fload_0        : load_local(floatType , 0); break;

       case Bytecodes::_fload_1        : load_local(floatType , 1); break;

       case Bytecodes::_fload_2        : load_local(floatType , 2); break;

       case Bytecodes::_fload_3        : load_local(floatType , 3); break;

       case Bytecodes::_dload_0        : load_local(doubleType, 0); break;

       case Bytecodes::_dload_1        : load_local(doubleType, 1); break;

       case Bytecodes::_dload_2        : load_local(doubleType, 2); break;

       case Bytecodes::_dload_3        : load_local(doubleType, 3); break;

       case Bytecodes::_aload_0        : load_local(objectType, 0); break;

       case Bytecodes::_aload_1        : load_local(objectType, 1); break;

       case Bytecodes::_aload_2        : load_local(objectType, 2); break;

       case Bytecodes::_aload_3        : load_local(objectType, 3); break;

       case Bytecodes::_iaload         : load_indexed(T_INT   ); break;

       case Bytecodes::_laload         : load_indexed(T_LONG  ); break;

       case Bytecodes::_faload         : load_indexed(T_FLOAT ); break;

       case Bytecodes::_daload         : load_indexed(T_DOUBLE); break;

       case Bytecodes::_aaload         : load_indexed(T_OBJECT); break;

       case Bytecodes::_baload         : load_indexed(T_BYTE  ); break;

       case Bytecodes::_caload         : load_indexed(T_CHAR  ); break;

       case Bytecodes::_saload         : load_indexed(T_SHORT ); break;

       case Bytecodes::_istore         : store_local(intType   , s.get_index()); break;

       case Bytecodes::_lstore         : store_local(longType  , s.get_index()); break;

       case Bytecodes::_fstore         : store_local(floatType , s.get_index()); break;

       case Bytecodes::_dstore         : store_local(doubleType, s.get_index()); break;

       case Bytecodes::_astore         : store_local(objectType, s.get_index()); break;

       case Bytecodes::_istore_0       : store_local(intType   , 0); break;

       case Bytecodes::_istore_1       : store_local(intType   , 1); break;

       case Bytecodes::_istore_2       : store_local(intType   , 2); break;

       case Bytecodes::_istore_3       : store_local(intType   , 3); break;

       case Bytecodes::_lstore_0       : store_local(longType  , 0); break;

       case Bytecodes::_lstore_1       : store_local(longType  , 1); break;

       case Bytecodes::_lstore_2       : store_local(longType  , 2); break;

       case Bytecodes::_lstore_3       : store_local(longType  , 3); break;

       case Bytecodes::_fstore_0       : store_local(floatType , 0); break;

       case Bytecodes::_fstore_1       : store_local(floatType , 1); break;

       case Bytecodes::_fstore_2       : store_local(floatType , 2); break;

       case Bytecodes::_fstore_3       : store_local(floatType , 3); break;

       case Bytecodes::_dstore_0       : store_local(doubleType, 0); break;

       case Bytecodes::_dstore_1       : store_local(doubleType, 1); break;

       case Bytecodes::_dstore_2       : store_local(doubleType, 2); break;

       case Bytecodes::_dstore_3       : store_local(doubleType, 3); break;

       case Bytecodes::_astore_0       : store_local(objectType, 0); break;

       case Bytecodes::_astore_1       : store_local(objectType, 1); break;

       case Bytecodes::_astore_2       : store_local(objectType, 2); break;

       case Bytecodes::_astore_3       : store_local(objectType, 3); break;

       case Bytecodes::_iastore        : store_indexed(T_INT   ); break;

       case Bytecodes::_lastore        : store_indexed(T_LONG  ); break;

       case Bytecodes::_fastore        : store_indexed(T_FLOAT ); break;

       case Bytecodes::_dastore        : store_indexed(T_DOUBLE); break;

       case Bytecodes::_aastore        : store_indexed(T_OBJECT); break;

       case Bytecodes::_bastore        : store_indexed(T_BYTE  ); break;

       case Bytecodes::_castore        : store_indexed(T_CHAR  ); break;

       case Bytecodes::_sastore        : store_indexed(T_SHORT ); break;

       case Bytecodes::_pop            : // fall through

       case Bytecodes::_pop2           : // fall through

       case Bytecodes::_dup            : // fall through

       case Bytecodes::_dup_x1         : // fall through

       case Bytecodes::_dup_x2         : // fall through

       case Bytecodes::_dup2           : // fall through

       case Bytecodes::_dup2_x1        : // fall through

       case Bytecodes::_dup2_x2        : // fall through

       case Bytecodes::_swap           : stack_op(code); break;

       case Bytecodes::_iadd           : arithmetic_op(intType   , code); break;

       case Bytecodes::_ladd           : arithmetic_op(longType  , code); break;

       case Bytecodes::_fadd           : arithmetic_op(floatType , code); break;

       case Bytecodes::_dadd           : arithmetic_op(doubleType, code); break;

       case Bytecodes::_isub           : arithmetic_op(intType   , code); break;

       case Bytecodes::_lsub           : arithmetic_op(longType  , code); break;

       case Bytecodes::_fsub           : arithmetic_op(floatType , code); break;

       case Bytecodes::_dsub           : arithmetic_op(doubleType, code); break;

       case Bytecodes::_imul           : arithmetic_op(intType   , code); break;

       case Bytecodes::_lmul           : arithmetic_op(longType  , code); break;

       case Bytecodes::_fmul           : arithmetic_op(floatType , code); break;

       case Bytecodes::_dmul           : arithmetic_op(doubleType, code); break;

       case Bytecodes::_idiv           : arithmetic_op(intType   , code, copy_state_for_exception()); break;

       case Bytecodes::_ldiv           : arithmetic_op(longType  , code, copy_state_for_exception()); break;

       case Bytecodes::_fdiv           : arithmetic_op(floatType , code); break;

       case Bytecodes::_ddiv           : arithmetic_op(doubleType, code); break;

       case Bytecodes::_irem           : arithmetic_op(intType   , code, copy_state_for_exception()); break;

       case Bytecodes::_lrem           : arithmetic_op(longType  , code, copy_state_for_exception()); break;

       case Bytecodes::_frem           : arithmetic_op(floatType , code); break;

       case Bytecodes::_drem           : arithmetic_op(doubleType, code); break;

       case Bytecodes::_ineg           : negate_op(intType   ); break;

       case Bytecodes::_lneg           : negate_op(longType  ); break;

       case Bytecodes::_fneg           : negate_op(floatType ); break;

       case Bytecodes::_dneg           : negate_op(doubleType); break;

       case Bytecodes::_ishl           : shift_op(intType , code); break;

       case Bytecodes::_lshl           : shift_op(longType, code); break;

       case Bytecodes::_ishr           : shift_op(intType , code); break;

       case Bytecodes::_lshr           : shift_op(longType, code); break;

       case Bytecodes::_iushr          : shift_op(intType , code); break;

       case Bytecodes::_lushr          : shift_op(longType, code); break;

       case Bytecodes::_iand           : logic_op(intType , code); break;

       case Bytecodes::_land           : logic_op(longType, code); break;

       case Bytecodes::_ior            : logic_op(intType , code); break;

       case Bytecodes::_lor            : logic_op(longType, code); break;

       case Bytecodes::_ixor           : logic_op(intType , code); break;

       case Bytecodes::_lxor           : logic_op(longType, code); break;

       case Bytecodes::_iinc           : increment(); break;

       case Bytecodes::_i2l            : convert(code, T_INT   , T_LONG  ); break;

       case Bytecodes::_i2f            : convert(code, T_INT   , T_FLOAT ); break;

       case Bytecodes::_i2d            : convert(code, T_INT   , T_DOUBLE); break;

       case Bytecodes::_l2i            : convert(code, T_LONG  , T_INT   ); break;

       case Bytecodes::_l2f            : convert(code, T_LONG  , T_FLOAT ); break;

       case Bytecodes::_l2d            : convert(code, T_LONG  , T_DOUBLE); break;

       case Bytecodes::_f2i            : convert(code, T_FLOAT , T_INT   ); break;

       case Bytecodes::_f2l            : convert(code, T_FLOAT , T_LONG  ); break;

       case Bytecodes::_f2d            : convert(code, T_FLOAT , T_DOUBLE); break;

       case Bytecodes::_d2i            : convert(code, T_DOUBLE, T_INT   ); break;

       case Bytecodes::_d2l            : convert(code, T_DOUBLE, T_LONG  ); break;

       case Bytecodes::_d2f            : convert(code, T_DOUBLE, T_FLOAT ); break;

       case Bytecodes::_i2b            : convert(code, T_INT   , T_BYTE  ); break;

       case Bytecodes::_i2c            : convert(code, T_INT   , T_CHAR  ); break;

       case Bytecodes::_i2s            : convert(code, T_INT   , T_SHORT ); break;

       case Bytecodes::_lcmp           : compare_op(longType  , code); break;

       case Bytecodes::_fcmpl          : compare_op(floatType , code); break;

       case Bytecodes::_fcmpg          : compare_op(floatType , code); break;

       case Bytecodes::_dcmpl          : compare_op(doubleType, code); break;

       case Bytecodes::_dcmpg          : compare_op(doubleType, code); break;

       case Bytecodes::_ifeq           : if_zero(intType   , If::eql); break;

       case Bytecodes::_ifne           : if_zero(intType   , If::neq); break;

       case Bytecodes::_iflt           : if_zero(intType   , If::lss); break;

       case Bytecodes::_ifge           : if_zero(intType   , If::geq); break;

       case Bytecodes::_ifgt           : if_zero(intType   , If::gtr); break;

       case Bytecodes::_ifle           : if_zero(intType   , If::leq); break;

       case Bytecodes::_if_icmpeq      : if_same(intType   , If::eql); break;

       case Bytecodes::_if_icmpne      : if_same(intType   , If::neq); break;

       case Bytecodes::_if_icmplt      : if_same(intType   , If::lss); break;

       case Bytecodes::_if_icmpge      : if_same(intType   , If::geq); break;

       case Bytecodes::_if_icmpgt      : if_same(intType   , If::gtr); break;

       case Bytecodes::_if_icmple      : if_same(intType   , If::leq); break;

       case Bytecodes::_if_acmpeq      : if_same(objectType, If::eql); break;

       case Bytecodes::_if_acmpne      : if_same(objectType, If::neq); break;

       case Bytecodes::_goto           : _goto(s.cur_bci(), s.get_dest()); break;

       case Bytecodes::_jsr            : jsr(s.get_dest()); break;

       case Bytecodes::_ret            : ret(s.get_index()); break;

       case Bytecodes::_tableswitch    : table_switch(); break;

       case Bytecodes::_lookupswitch   : lookup_switch(); break;

       case Bytecodes::_ireturn        : method_return(ipop()); break;

       case Bytecodes::_lreturn        : method_return(lpop()); break;

       case Bytecodes::_freturn        : method_return(fpop()); break;

       case Bytecodes::_dreturn        : method_return(dpop()); break;

       case Bytecodes::_areturn        : method_return(apop()); break;

       case Bytecodes::_return         : method_return(NULL  ); break;

       case Bytecodes::_getstatic      : // fall through

       case Bytecodes::_putstatic      : // fall through

       case Bytecodes::_getfield       : // fall through

       case Bytecodes::_putfield       : access_field(code); break;

       case Bytecodes::_invokevirtual  : // fall through

       case Bytecodes::_invokespecial  : // fall through

       case Bytecodes::_invokestatic   : // fall through

       case Bytecodes::_invokedynamic  : // fall through

       case Bytecodes::_invokeinterface: invoke(code); break;

       case Bytecodes::_new            : new_instance(s.get_index_u2()); break;

       case Bytecodes::_newarray       : new_type_array(); break;

       case Bytecodes::_anewarray      : new_object_array(); break;

       case Bytecodes::_arraylength    : { ValueStack* state_before = copy_state_for_exception(); ipush(append(new ArrayLength(apop(), state_before))); break; }

       case Bytecodes::_athrow         : throw_op(s.cur_bci()); break;

       case Bytecodes::_checkcast      : check_cast(s.get_index_u2()); break;

       case Bytecodes::_instanceof     : instance_of(s.get_index_u2()); break;

       case Bytecodes::_monitorenter   : monitorenter(apop(), s.cur_bci()); break;

       case Bytecodes::_monitorexit    : monitorexit (apop(), s.cur_bci()); break;

       case Bytecodes::_wide           : ShouldNotReachHere(); break;

       case Bytecodes::_multianewarray : new_multi_array(s.cur_bcp()[3]); break;

       case Bytecodes::_ifnull         : if_null(objectType, If::eql); break;

       case Bytecodes::_ifnonnull      : if_null(objectType, If::neq); break;

       case Bytecodes::_goto_w         : _goto(s.cur_bci(), s.get_far_dest()); break;

       case Bytecodes::_jsr_w          : jsr(s.get_far_dest()); break;

       case Bytecodes::_breakpoint     : BAILOUT_("concurrent setting of breakpoint", NULL);

       default                         : ShouldNotReachHere(); break;

     }

     // save current bci to setup Goto at the end

     prev_bci = s.cur_bci();

   }

   CHECK_BAILOUT_(NULL);

   // stop processing of this block (see try_inline_full)

   if (_skip_block) {

     _skip_block = false;

     assert(_last && _last->as_BlockEnd(), "");

     return _last->as_BlockEnd();

   }

   // if there are any, check if last instruction is a BlockEnd instruction

   BlockEnd* end = last()->as_BlockEnd();

   if (end == NULL) {

     // all blocks must end with a BlockEnd instruction => add a Goto

     end = new Goto(block_at(s.cur_bci()), false);

     append(end);

   }

   assert(end == last()->as_BlockEnd(), "inconsistency");

   assert(end->state() != NULL, "state must already be present");

   assert(end->as_Return() == NULL || end->as_Throw() == NULL || end->state()->stack_size() == 0, "stack not needed for return and throw");

   // connect to begin & set state

   // NOTE that inlining may have changed the block we are parsing

   block()->set_end(end);

   // propagate state

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

     BlockBegin* sux = end->sux_at(i);

     assert(sux->is_predecessor(block()), "predecessor missing");

     // be careful, bailout if bytecodes are strange

     if (!sux->try_merge(end->state())) BAILOUT_("block join failed", NULL);

     scope_data()->add_to_work_list(end->sux_at(i));

   }

   scope_data()->set_stream(NULL);

   // done

   return end;

 }

 void GraphBuilder::iterate_all_blocks(bool start_in_current_block_for_inlining) {

   do {

     if (start_in_current_block_for_inlining && !bailed_out()) {

       iterate_bytecodes_for_block(0);

       start_in_current_block_for_inlining = false;

     } else {

       BlockBegin* b;

       while ((b = scope_data()->remove_from_work_list()) != NULL) {

         if (!b->is_set(BlockBegin::was_visited_flag)) {

           if (b->is_set(BlockBegin::osr_entry_flag)) {

             // we're about to parse the osr entry block, so make sure

             // we setup the OSR edge leading into this block so that

             // Phis get setup correctly.

             setup_osr_entry_block();

             // this is no longer the osr entry block, so clear it.

             b->clear(BlockBegin::osr_entry_flag);

           }

           b->set(BlockBegin::was_visited_flag);

           connect_to_end(b);

         }

       }

     }

   } while (!bailed_out() && !scope_data()->is_work_list_empty());

 }

 bool GraphBuilder::_can_trap      [Bytecodes::number_of_java_codes];

 void GraphBuilder::initialize() {

   // the following bytecodes are assumed to potentially

   // throw exceptions in compiled code - note that e.g.

   // monitorexit & the return bytecodes do not throw

   // exceptions since monitor pairing proved that they

   // succeed (if monitor pairing succeeded)

   Bytecodes::Code can_trap_list[] =

     { Bytecodes::_ldc

     , Bytecodes::_ldc_w

     , Bytecodes::_ldc2_w

     , Bytecodes::_iaload

     , Bytecodes::_laload

     , Bytecodes::_faload

     , Bytecodes::_daload

     , Bytecodes::_aaload

     , Bytecodes::_baload

     , Bytecodes::_caload

     , Bytecodes::_saload

     , Bytecodes::_iastore

     , Bytecodes::_lastore

     , Bytecodes::_fastore

     , Bytecodes::_dastore

     , Bytecodes::_aastore

     , Bytecodes::_bastore

     , Bytecodes::_castore

     , Bytecodes::_sastore

     , Bytecodes::_idiv