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

 /*

  * Copyright (c) 2005, 2012, 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_Compilation.hpp"

 #include "c1/c1_FrameMap.hpp"

 #include "c1/c1_Instruction.hpp"

 #include "c1/c1_LIRAssembler.hpp"

 #include "c1/c1_LIRGenerator.hpp"

 #include "c1/c1_ValueStack.hpp"

 #include "ci/ciArrayKlass.hpp"

 #include "ci/ciInstance.hpp"

 #include "ci/ciObjArray.hpp"

 #include "runtime/sharedRuntime.hpp"

 #include "runtime/stubRoutines.hpp"

 #include "utilities/bitMap.inline.hpp"

 #include "utilities/macros.hpp"

 #if INCLUDE_ALL_GCS

 #include "gc_implementation/g1/heapRegion.hpp"

 #endif // INCLUDE_ALL_GCS

 #ifdef ASSERT

 #define __ gen()->lir(__FILE__, __LINE__)->

 #else

 #define __ gen()->lir()->

 #endif

 // TODO: ARM - Use some recognizable constant which still fits architectural constraints

 #ifdef ARM

 #define PATCHED_ADDR  (204)

 #else

 #define PATCHED_ADDR  (max_jint)

 #endif

 void PhiResolverState::reset(int max_vregs) {

   // Initialize array sizes

   _virtual_operands.at_put_grow(max_vregs - 1, NULL, NULL);

   _virtual_operands.trunc_to(0);

   _other_operands.at_put_grow(max_vregs - 1, NULL, NULL);

   _other_operands.trunc_to(0);

   _vreg_table.at_put_grow(max_vregs - 1, NULL, NULL);

   _vreg_table.trunc_to(0);

 }

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

 // PhiResolver

 // Resolves cycles:

 //

 //  r1 := r2  becomes  temp := r1

 //  r2 := r1           r1 := r2

 //                     r2 := temp

 // and orders moves:

 //

 //  r2 := r3  becomes  r1 := r2

 //  r1 := r2           r2 := r3

 PhiResolver::PhiResolver(LIRGenerator* gen, int max_vregs)

  : _gen(gen)

  , _state(gen->resolver_state())

  , _temp(LIR_OprFact::illegalOpr)

 {

   // reinitialize the shared state arrays

   _state.reset(max_vregs);

 }

 void PhiResolver::emit_move(LIR_Opr src, LIR_Opr dest) {

   assert(src->is_valid(), "");

   assert(dest->is_valid(), "");

   __ move(src, dest);

 }

 void PhiResolver::move_temp_to(LIR_Opr dest) {

   assert(_temp->is_valid(), "");

   emit_move(_temp, dest);

   NOT_PRODUCT(_temp = LIR_OprFact::illegalOpr);

 }

 void PhiResolver::move_to_temp(LIR_Opr src) {

   assert(_temp->is_illegal(), "");

   _temp = _gen->new_register(src->type());

   emit_move(src, _temp);

 }

 // Traverse assignment graph in depth first order and generate moves in post order

 // ie. two assignments: b := c, a := b start with node c:

 // Call graph: move(NULL, c) -> move(c, b) -> move(b, a)

 // Generates moves in this order: move b to a and move c to b

 // ie. cycle a := b, b := a start with node a

 // Call graph: move(NULL, a) -> move(a, b) -> move(b, a)

 // Generates moves in this order: move b to temp, move a to b, move temp to a

 void PhiResolver::move(ResolveNode* src, ResolveNode* dest) {

   if (!dest->visited()) {

     dest->set_visited();

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

       move(dest, dest->destination_at(i));

     }

   } else if (!dest->start_node()) {

     // cylce in graph detected

     assert(_loop == NULL, "only one loop valid!");

     _loop = dest;

     move_to_temp(src->operand());

     return;

   } // else dest is a start node

   if (!dest->assigned()) {

     if (_loop == dest) {

       move_temp_to(dest->operand());

       dest->set_assigned();

     } else if (src != NULL) {

       emit_move(src->operand(), dest->operand());

       dest->set_assigned();

     }

   }

 }

 PhiResolver::~PhiResolver() {

   int i;

   // resolve any cycles in moves from and to virtual registers

   for (i = virtual_operands().length() - 1; i >= 0; i --) {

     ResolveNode* node = virtual_operands()[i];

     if (!node->visited()) {

       _loop = NULL;

       move(NULL, node);

       node->set_start_node();

       assert(_temp->is_illegal(), "move_temp_to() call missing");

     }

   }

   // generate move for move from non virtual register to abitrary destination

   for (i = other_operands().length() - 1; i >= 0; i --) {

     ResolveNode* node = other_operands()[i];

     for (int j = node->no_of_destinations() - 1; j >= 0; j --) {

       emit_move(node->operand(), node->destination_at(j)->operand());

     }

   }

 }

 ResolveNode* PhiResolver::create_node(LIR_Opr opr, bool source) {

   ResolveNode* node;

   if (opr->is_virtual()) {

     int vreg_num = opr->vreg_number();

     node = vreg_table().at_grow(vreg_num, NULL);

     assert(node == NULL || node->operand() == opr, "");

     if (node == NULL) {

       node = new ResolveNode(opr);

       vreg_table()[vreg_num] = node;

     }

     // Make sure that all virtual operands show up in the list when

     // they are used as the source of a move.

     if (source && !virtual_operands().contains(node)) {

       virtual_operands().append(node);

     }

   } else {

     assert(source, "");

     node = new ResolveNode(opr);

     other_operands().append(node);

   }

   return node;

 }

 void PhiResolver::move(LIR_Opr src, LIR_Opr dest) {

   assert(dest->is_virtual(), "");

   // tty->print("move "); src->print(); tty->print(" to "); dest->print(); tty->cr();

   assert(src->is_valid(), "");

   assert(dest->is_valid(), "");

   ResolveNode* source = source_node(src);

   source->append(destination_node(dest));

 }

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

 // LIRItem

 void LIRItem::set_result(LIR_Opr opr) {

   assert(value()->operand()->is_illegal() || value()->operand()->is_constant(), "operand should never change");

   value()->set_operand(opr);

   if (opr->is_virtual()) {

     _gen->_instruction_for_operand.at_put_grow(opr->vreg_number(), value(), NULL);

   }

   _result = opr;

 }

 void LIRItem::load_item() {

   if (result()->is_illegal()) {

     // update the items result

     _result = value()->operand();

   }

   if (!result()->is_register()) {

     LIR_Opr reg = _gen->new_register(value()->type());

     __ move(result(), reg);

     if (result()->is_constant()) {

       _result = reg;

     } else {

       set_result(reg);

     }

   }

 }

 void LIRItem::load_for_store(BasicType type) {

   if (_gen->can_store_as_constant(value(), type)) {

     _result = value()->operand();

     if (!_result->is_constant()) {

       _result = LIR_OprFact::value_type(value()->type());

     }

   } else if (type == T_BYTE || type == T_BOOLEAN) {

     load_byte_item();

   } else {

     load_item();

   }

 }

 void LIRItem::load_item_force(LIR_Opr reg) {

   LIR_Opr r = result();

   if (r != reg) {

 #if !defined(ARM) && !defined(E500V2)

     if (r->type() != reg->type()) {

       // moves between different types need an intervening spill slot

       r = _gen->force_to_spill(r, reg->type());

     }

 #endif

     __ move(r, reg);

     _result = reg;

   }

 }

 ciObject* LIRItem::get_jobject_constant() const {

   ObjectType* oc = type()->as_ObjectType();

   if (oc) {

     return oc->constant_value();

   }

   return NULL;

 }

 jint LIRItem::get_jint_constant() const {

   assert(is_constant() && value() != NULL, "");

   assert(type()->as_IntConstant() != NULL, "type check");

   return type()->as_IntConstant()->value();

 }

 jint LIRItem::get_address_constant() const {

   assert(is_constant() && value() != NULL, "");

   assert(type()->as_AddressConstant() != NULL, "type check");

   return type()->as_AddressConstant()->value();

 }

 jfloat LIRItem::get_jfloat_constant() const {

   assert(is_constant() && value() != NULL, "");

   assert(type()->as_FloatConstant() != NULL, "type check");

   return type()->as_FloatConstant()->value();

 }

 jdouble LIRItem::get_jdouble_constant() const {

   assert(is_constant() && value() != NULL, "");

   assert(type()->as_DoubleConstant() != NULL, "type check");

   return type()->as_DoubleConstant()->value();

 }

 jlong LIRItem::get_jlong_constant() const {

   assert(is_constant() && value() != NULL, "");

   assert(type()->as_LongConstant() != NULL, "type check");

   return type()->as_LongConstant()->value();

 }

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

 void LIRGenerator::init() {

   _bs = Universe::heap()->barrier_set();

 }

 void LIRGenerator::block_do_prolog(BlockBegin* block) {

 #ifndef PRODUCT

   if (PrintIRWithLIR) {

     block->print();

   }

 #endif

   // set up the list of LIR instructions

   assert(block->lir() == NULL, "LIR list already computed for this block");

   _lir = new LIR_List(compilation(), block);

   block->set_lir(_lir);

   __ branch_destination(block->label());

   if (LIRTraceExecution &&

       Compilation::current()->hir()->start()->block_id() != block->block_id() &&

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

     assert(block->lir()->instructions_list()->length() == 1, "should come right after br_dst");

     trace_block_entry(block);

   }

 }

 void LIRGenerator::block_do_epilog(BlockBegin* block) {

 #ifndef PRODUCT

   if (PrintIRWithLIR) {

     tty->cr();

   }

 #endif

   // LIR_Opr for unpinned constants shouldn't be referenced by other

   // blocks so clear them out after processing the block.

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

     _unpinned_constants.at(i)->clear_operand();

   }

   _unpinned_constants.trunc_to(0);

   // clear our any registers for other local constants

   _constants.trunc_to(0);

   _reg_for_constants.trunc_to(0);

 }

 void LIRGenerator::block_do(BlockBegin* block) {

   CHECK_BAILOUT();

   block_do_prolog(block);

   set_block(block);

   for (Instruction* instr = block; instr != NULL; instr = instr->next()) {

     if (instr->is_pinned()) do_root(instr);

   }

   set_block(NULL);

   block_do_epilog(block);

 }

 //-------------------------LIRGenerator-----------------------------

 // This is where the tree-walk starts; instr must be root;

 void LIRGenerator::do_root(Value instr) {

   CHECK_BAILOUT();

   InstructionMark im(compilation(), instr);

   assert(instr->is_pinned(), "use only with roots");

   assert(instr->subst() == instr, "shouldn't have missed substitution");

   instr->visit(this);

   assert(!instr->has_uses() || instr->operand()->is_valid() ||

          instr->as_Constant() != NULL || bailed_out(), "invalid item set");

 }

 // This is called for each node in tree; the walk stops if a root is reached

 void LIRGenerator::walk(Value instr) {

   InstructionMark im(compilation(), instr);

   //stop walk when encounter a root

   if (instr->is_pinned() && instr->as_Phi() == NULL || instr->operand()->is_valid()) {

     assert(instr->operand() != LIR_OprFact::illegalOpr || instr->as_Constant() != NULL, "this root has not yet been visited");

   } else {

     assert(instr->subst() == instr, "shouldn't have missed substitution");

     instr->visit(this);

     // assert(instr->use_count() > 0 || instr->as_Phi() != NULL, "leaf instruction must have a use");

   }

 }

 CodeEmitInfo* LIRGenerator::state_for(Instruction* x, ValueStack* state, bool ignore_xhandler) {

   assert(state != NULL, "state must be defined");

 #ifndef PRODUCT

   state->verify();

 #endif

   ValueStack* s = state;

   for_each_state(s) {

     if (s->kind() == ValueStack::EmptyExceptionState) {

       assert(s->stack_size() == 0 && s->locals_size() == 0 && (s->locks_size() == 0 || s->locks_size() == 1), "state must be empty");

       continue;

     }

     int index;

     Value value;

     for_each_stack_value(s, index, value) {

       assert(value->subst() == value, "missed substitution");

       if (!value->is_pinned() && value->as_Constant() == NULL && value->as_Local() == NULL) {

         walk(value);

         assert(value->operand()->is_valid(), "must be evaluated now");

       }

     }

     int bci = s->bci();

     IRScope* scope = s->scope();

     ciMethod* method = scope->method();

     MethodLivenessResult liveness = method->liveness_at_bci(bci);

     if (bci == SynchronizationEntryBCI) {

       if (x->as_ExceptionObject() || x->as_Throw()) {

         // all locals are dead on exit from the synthetic unlocker

         liveness.clear();

       } else {

         assert(x->as_MonitorEnter() || x->as_ProfileInvoke(), "only other cases are MonitorEnter and ProfileInvoke");

       }

     }

     if (!liveness.is_valid()) {

       // Degenerate or breakpointed method.

       bailout("Degenerate or breakpointed method");

     } else {

       assert((int)liveness.size() == s->locals_size(), "error in use of liveness");

       for_each_local_value(s, index, value) {

         assert(value->subst() == value, "missed substition");

         if (liveness.at(index) && !value->type()->is_illegal()) {

           if (!value->is_pinned() && value->as_Constant() == NULL && value->as_Local() == NULL) {

             walk(value);

             assert(value->operand()->is_valid(), "must be evaluated now");

           }

         } else {

           // NULL out this local so that linear scan can assume that all non-NULL values are live.

           s->invalidate_local(index);

         }

       }

     }

   }

   return new CodeEmitInfo(state, ignore_xhandler ? NULL : x->exception_handlers(), x->check_flag(Instruction::DeoptimizeOnException));

 }

 CodeEmitInfo* LIRGenerator::state_for(Instruction* x) {

   return state_for(x, x->exception_state());

 }

 void LIRGenerator::klass2reg_with_patching(LIR_Opr r, ciMetadata* obj, CodeEmitInfo* info) {

   if (!obj->is_loaded() || PatchALot) {

     assert(info != NULL, "info must be set if class is not loaded");

     __ klass2reg_patch(NULL, r, info);

   } else {

     // no patching needed

     __ metadata2reg(obj->constant_encoding(), r);

   }

 }

 void LIRGenerator::array_range_check(LIR_Opr array, LIR_Opr index,

                                     CodeEmitInfo* null_check_info, CodeEmitInfo* range_check_info) {

   CodeStub* stub = new RangeCheckStub(range_check_info, index);

   if (index->is_constant()) {

     cmp_mem_int(lir_cond_belowEqual, array, arrayOopDesc::length_offset_in_bytes(),

                 index->as_jint(), null_check_info);

     __ branch(lir_cond_belowEqual, T_INT, stub); // forward branch

   } else {

     cmp_reg_mem(lir_cond_aboveEqual, index, array,

                 arrayOopDesc::length_offset_in_bytes(), T_INT, null_check_info);

     __ branch(lir_cond_aboveEqual, T_INT, stub); // forward branch

   }

 }

 void LIRGenerator::nio_range_check(LIR_Opr buffer, LIR_Opr index, LIR_Opr result, CodeEmitInfo* info) {

   CodeStub* stub = new RangeCheckStub(info, index, true);

   if (index->is_constant()) {

     cmp_mem_int(lir_cond_belowEqual, buffer, java_nio_Buffer::limit_offset(), index->as_jint(), info);

     __ branch(lir_cond_belowEqual, T_INT, stub); // forward branch

   } else {

     cmp_reg_mem(lir_cond_aboveEqual, index, buffer,

                 java_nio_Buffer::limit_offset(), T_INT, info);

     __ branch(lir_cond_aboveEqual, T_INT, stub); // forward branch

   }

   __ move(index, result);

 }

 void LIRGenerator::arithmetic_op(Bytecodes::Code code, LIR_Opr result, LIR_Opr left, LIR_Opr right, bool is_strictfp, LIR_Opr tmp_op, CodeEmitInfo* info) {

   LIR_Opr result_op = result;

   LIR_Opr left_op   = left;

   LIR_Opr right_op  = right;

   if (TwoOperandLIRForm && left_op != result_op) {

     assert(right_op != result_op, "malformed");

     __ move(left_op, result_op);

     left_op = result_op;

   }

   switch(code) {

     case Bytecodes::_dadd:

     case Bytecodes::_fadd:

     case Bytecodes::_ladd:

     case Bytecodes::_iadd:  __ add(left_op, right_op, result_op); break;

     case Bytecodes::_fmul:

     case Bytecodes::_lmul:  __ mul(left_op, right_op, result_op); break;

     case Bytecodes::_dmul:

       {

         if (is_strictfp) {

           __ mul_strictfp(left_op, right_op, result_op, tmp_op); break;

         } else {

           __ mul(left_op, right_op, result_op); break;

         }

       }

       break;

     case Bytecodes::_imul:

       {

         bool    did_strength_reduce = false;

         if (right->is_constant()) {

           int c = right->as_jint();

           if (is_power_of_2(c)) {

             // do not need tmp here

             __ shift_left(left_op, exact_log2(c), result_op);

             did_strength_reduce = true;

           } else {

             did_strength_reduce = strength_reduce_multiply(left_op, c, result_op, tmp_op);

           }

         }

         // we couldn't strength reduce so just emit the multiply

         if (!did_strength_reduce) {

           __ mul(left_op, right_op, result_op);

         }

       }

       break;

     case Bytecodes::_dsub:

     case Bytecodes::_fsub:

     case Bytecodes::_lsub:

     case Bytecodes::_isub: __ sub(left_op, right_op, result_op); break;

     case Bytecodes::_fdiv: __ div (left_op, right_op, result_op); break;

     // ldiv and lrem are implemented with a direct runtime call

     case Bytecodes::_ddiv:

       {

         if (is_strictfp) {

           __ div_strictfp (left_op, right_op, result_op, tmp_op); break;

         } else {

           __ div (left_op, right_op, result_op); break;

         }

       }

       break;

     case Bytecodes::_drem:

     case Bytecodes::_frem: __ rem (left_op, right_op, result_op); break;

     default: ShouldNotReachHere();

   }

 }

 void LIRGenerator::arithmetic_op_int(Bytecodes::Code code, LIR_Opr result, LIR_Opr left, LIR_Opr right, LIR_Opr tmp) {

   arithmetic_op(code, result, left, right, false, tmp);

 }

 void LIRGenerator::arithmetic_op_long(Bytecodes::Code code, LIR_Opr result, LIR_Opr left, LIR_Opr right, CodeEmitInfo* info) {

   arithmetic_op(code, result, left, right, false, LIR_OprFact::illegalOpr, info);

 }

 void LIRGenerator::arithmetic_op_fpu(Bytecodes::Code code, LIR_Opr result, LIR_Opr left, LIR_Opr right, bool is_strictfp, LIR_Opr tmp) {

   arithmetic_op(code, result, left, right, is_strictfp, tmp);

 }

 void LIRGenerator::shift_op(Bytecodes::Code code, LIR_Opr result_op, LIR_Opr value, LIR_Opr count, LIR_Opr tmp) {

   if (TwoOperandLIRForm && value != result_op) {

     assert(count != result_op, "malformed");

     __ move(value, result_op);

     value = result_op;

   }

   assert(count->is_constant() || count->is_register(), "must be");

   switch(code) {

   case Bytecodes::_ishl:

   case Bytecodes::_lshl: __ shift_left(value, count, result_op, tmp); break;

   case Bytecodes::_ishr:

   case Bytecodes::_lshr: __ shift_right(value, count, result_op, tmp); break;

   case Bytecodes::_iushr:

   case Bytecodes::_lushr: __ unsigned_shift_right(value, count, result_op, tmp); break;

   default: ShouldNotReachHere();

   }

 }

 void LIRGenerator::logic_op (Bytecodes::Code code, LIR_Opr result_op, LIR_Opr left_op, LIR_Opr right_op) {

   if (TwoOperandLIRForm && left_op != result_op) {

     assert(right_op != result_op, "malformed");

     __ move(left_op, result_op);

     left_op = result_op;

   }

   switch(code) {

     case Bytecodes::_iand:

     case Bytecodes::_land:  __ logical_and(left_op, right_op, result_op); break;

     case Bytecodes::_ior:

     case Bytecodes::_lor:   __ logical_or(left_op, right_op, result_op);  break;

     case Bytecodes::_ixor:

     case Bytecodes::_lxor:  __ logical_xor(left_op, right_op, result_op); break;

     default: ShouldNotReachHere();

   }

 }

 void LIRGenerator::monitor_enter(LIR_Opr object, LIR_Opr lock, LIR_Opr hdr, LIR_Opr scratch, int monitor_no, CodeEmitInfo* info_for_exception, CodeEmitInfo* info) {

   if (!GenerateSynchronizationCode) return;

   // for slow path, use debug info for state after successful locking

   CodeStub* slow_path = new MonitorEnterStub(object, lock, info);

   __ load_stack_address_monitor(monitor_no, lock);

   // for handling NullPointerException, use debug info representing just the lock stack before this monitorenter

   __ lock_object(hdr, object, lock, scratch, slow_path, info_for_exception);

 }

 void LIRGenerator::monitor_exit(LIR_Opr object, LIR_Opr lock, LIR_Opr new_hdr, LIR_Opr scratch, int monitor_no) {

   if (!GenerateSynchronizationCode) return;

   // setup registers

   LIR_Opr hdr = lock;

   lock = new_hdr;

   CodeStub* slow_path = new MonitorExitStub(lock, UseFastLocking, monitor_no);

   __ load_stack_address_monitor(monitor_no, lock);

   __ unlock_object(hdr, object, lock, scratch, slow_path);

 }

 void LIRGenerator::new_instance(LIR_Opr dst, ciInstanceKlass* klass, LIR_Opr scratch1, LIR_Opr scratch2, LIR_Opr scratch3, LIR_Opr scratch4, LIR_Opr klass_reg, CodeEmitInfo* info) {

   klass2reg_with_patching(klass_reg, klass, info);

   // If klass is not loaded we do not know if the klass has finalizers:

   if (UseFastNewInstance && klass->is_loaded()

       && !Klass::layout_helper_needs_slow_path(klass->layout_helper())) {

     Runtime1::StubID stub_id = klass->is_initialized() ? Runtime1::fast_new_instance_id : Runtime1::fast_new_instance_init_check_id;

     CodeStub* slow_path = new NewInstanceStub(klass_reg, dst, klass, info, stub_id);

     assert(klass->is_loaded(), "must be loaded");

     // allocate space for instance

     assert(klass->size_helper() >= 0, "illegal instance size");

     const int instance_size = align_object_size(klass->size_helper());

     __ allocate_object(dst, scratch1, scratch2, scratch3, scratch4,

                        oopDesc::header_size(), instance_size, klass_reg, !klass->is_initialized(), slow_path);

   } else {

     CodeStub* slow_path = new NewInstanceStub(klass_reg, dst, klass, info, Runtime1::new_instance_id);

     __ branch(lir_cond_always, T_ILLEGAL, slow_path);

     __ branch_destination(slow_path->continuation());

   }

 }

 static bool is_constant_zero(Instruction* inst) {

   IntConstant* c = inst->type()->as_IntConstant();

   if (c) {

     return (c->value() == 0);

   }

   return false;

 }

 static bool positive_constant(Instruction* inst) {

   IntConstant* c = inst->type()->as_IntConstant();

   if (c) {

     return (c->value() >= 0);

   }

   return false;

 }

 static ciArrayKlass* as_array_klass(ciType* type) {

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

     return (ciArrayKlass*)type;

   } else {

     return NULL;

   }

 }

 static Value maxvalue(IfOp* ifop) {

   switch (ifop->cond()) {

     case If::eql: return NULL;

     case If::neq: return NULL;

     case If::lss: // x <  y ? x : y

     case If::leq: // x <= y ? x : y

       if (ifop->x() == ifop->tval() &&

           ifop->y() == ifop->fval()) return ifop->y();

       return NULL;

     case If::gtr: // x >  y ? y : x

     case If::geq: // x >= y ? y : x

       if (ifop->x() == ifop->tval() &&

           ifop->y() == ifop->fval()) return ifop->y();

       return NULL;

   }

 }

 static ciType* phi_declared_type(Phi* phi) {

   ciType* t = phi->operand_at(0)->declared_type();

   if (t == NULL) {

     return NULL;

   }

   for(int i = 1; i < phi->operand_count(); i++) {

     if (t != phi->operand_at(i)->declared_type()) {

       return NULL;

     }

   }

   return t;

 }

 void LIRGenerator::arraycopy_helper(Intrinsic* x, int* flagsp, ciArrayKlass** expected_typep) {

   Instruction* src     = x->argument_at(0);

   Instruction* src_pos = x->argument_at(1);

   Instruction* dst     = x->argument_at(2);

   Instruction* dst_pos = x->argument_at(3);

   Instruction* length  = x->argument_at(4);

   // first try to identify the likely type of the arrays involved

   ciArrayKlass* expected_type = NULL;

   bool is_exact = false, src_objarray = false, dst_objarray = false;

   {

     ciArrayKlass* src_exact_type    = as_array_klass(src->exact_type());

     ciArrayKlass* src_declared_type = as_array_klass(src->declared_type());

     Phi* phi;

     if (src_declared_type == NULL && (phi = src->as_Phi()) != NULL) {

       src_declared_type = as_array_klass(phi_declared_type(phi));

     }

     ciArrayKlass* dst_exact_type    = as_array_klass(dst->exact_type());

     ciArrayKlass* dst_declared_type = as_array_klass(dst->declared_type());

     if (dst_declared_type == NULL && (phi = dst->as_Phi()) != NULL) {

       dst_declared_type = as_array_klass(phi_declared_type(phi));

     }

     if (src_exact_type != NULL && src_exact_type == dst_exact_type) {

       // the types exactly match so the type is fully known

       is_exact = true;

       expected_type = src_exact_type;

     } else if (dst_exact_type != NULL && dst_exact_type->is_obj_array_klass()) {

       ciArrayKlass* dst_type = (ciArrayKlass*) dst_exact_type;

       ciArrayKlass* src_type = NULL;

       if (src_exact_type != NULL && src_exact_type->is_obj_array_klass()) {

         src_type = (ciArrayKlass*) src_exact_type;

       } else if (src_declared_type != NULL && src_declared_type->is_obj_array_klass()) {

         src_type = (ciArrayKlass*) src_declared_type;

       }

       if (src_type != NULL) {

         if (src_type->element_type()->is_subtype_of(dst_type->element_type())) {

           is_exact = true;

           expected_type = dst_type;

         }

       }

     }

     // at least pass along a good guess

     if (expected_type == NULL) expected_type = dst_exact_type;

     if (expected_type == NULL) expected_type = src_declared_type;

     if (expected_type == NULL) expected_type = dst_declared_type;

     src_objarray = (src_exact_type && src_exact_type->is_obj_array_klass()) || (src_declared_type && src_declared_type->is_obj_array_klass());

     dst_objarray = (dst_exact_type && dst_exact_type->is_obj_array_klass()) || (dst_declared_type && dst_declared_type->is_obj_array_klass());

   }

   // if a probable array type has been identified, figure out if any

   // of the required checks for a fast case can be elided.

   int flags = LIR_OpArrayCopy::all_flags;

   if (!src_objarray)

     flags &= ~LIR_OpArrayCopy::src_objarray;

   if (!dst_objarray)

     flags &= ~LIR_OpArrayCopy::dst_objarray;

   if (!x->arg_needs_null_check(0))

     flags &= ~LIR_OpArrayCopy::src_null_check;

   if (!x->arg_needs_null_check(2))

     flags &= ~LIR_OpArrayCopy::dst_null_check;

   if (expected_type != NULL) {

     Value length_limit = NULL;

     IfOp* ifop = length->as_IfOp();

     if (ifop != NULL) {

       // look for expressions like min(v, a.length) which ends up as

       //   x > y ? y : x  or  x >= y ? y : x

       if ((ifop->cond() == If::gtr || ifop->cond() == If::geq) &&

           ifop->x() == ifop->fval() &&

           ifop->y() == ifop->tval()) {

         length_limit = ifop->y();

       }

     }

     // try to skip null checks and range checks

     NewArray* src_array = src->as_NewArray();

     if (src_array != NULL) {

       flags &= ~LIR_OpArrayCopy::src_null_check;

       if (length_limit != NULL &&

           src_array->length() == length_limit &&

           is_constant_zero(src_pos)) {

         flags &= ~LIR_OpArrayCopy::src_range_check;

       }

     }

     NewArray* dst_array = dst->as_NewArray();

     if (dst_array != NULL) {

       flags &= ~LIR_OpArrayCopy::dst_null_check;

       if (length_limit != NULL &&

           dst_array->length() == length_limit &&

           is_constant_zero(dst_pos)) {

         flags &= ~LIR_OpArrayCopy::dst_range_check;

       }

     }

     // check from incoming constant values

     if (positive_constant(src_pos))

       flags &= ~LIR_OpArrayCopy::src_pos_positive_check;

     if (positive_constant(dst_pos))

       flags &= ~LIR_OpArrayCopy::dst_pos_positive_check;

     if (positive_constant(length))

       flags &= ~LIR_OpArrayCopy::length_positive_check;

     // see if the range check can be elided, which might also imply

     // that src or dst is non-null.

     ArrayLength* al = length->as_ArrayLength();

     if (al != NULL) {

       if (al->array() == src) {

         // it's the length of the source array

         flags &= ~LIR_OpArrayCopy::length_positive_check;

         flags &= ~LIR_OpArrayCopy::src_null_check;

         if (is_constant_zero(src_pos))

           flags &= ~LIR_OpArrayCopy::src_range_check;

       }

       if (al->array() == dst) {

         // it's the length of the destination array

         flags &= ~LIR_OpArrayCopy::length_positive_check;

         flags &= ~LIR_OpArrayCopy::dst_null_check;

         if (is_constant_zero(dst_pos))

           flags &= ~LIR_OpArrayCopy::dst_range_check;

       }

     }

     if (is_exact) {

       flags &= ~LIR_OpArrayCopy::type_check;

     }

   }

   IntConstant* src_int = src_pos->type()->as_IntConstant();

   IntConstant* dst_int = dst_pos->type()->as_IntConstant();

   if (src_int && dst_int) {

     int s_offs = src_int->value();

     int d_offs = dst_int->value();

     if (src_int->value() >= dst_int->value()) {

       flags &= ~LIR_OpArrayCopy::overlapping;

     }

     if (expected_type != NULL) {

       BasicType t = expected_type->element_type()->basic_type();

       int element_size = type2aelembytes(t);

       if (((arrayOopDesc::base_offset_in_bytes(t) + s_offs * element_size) % HeapWordSize == 0) &&

           ((arrayOopDesc::base_offset_in_bytes(t) + d_offs * element_size) % HeapWordSize == 0)) {

         flags &= ~LIR_OpArrayCopy::unaligned;

       }

     }

   } else if (src_pos == dst_pos || is_constant_zero(dst_pos)) {

     // src and dest positions are the same, or dst is zero so assume

     // nonoverlapping copy.

     flags &= ~LIR_OpArrayCopy::overlapping;

   }

   if (src == dst) {

     // moving within a single array so no type checks are needed

     if (flags & LIR_OpArrayCopy::type_check) {

       flags &= ~LIR_OpArrayCopy::type_check;

     }

   }

   *flagsp = flags;

   *expected_typep = (ciArrayKlass*)expected_type;

 }

 LIR_Opr LIRGenerator::round_item(LIR_Opr opr) {

   assert(opr->is_register(), "why spill if item is not register?");

   if (RoundFPResults && UseSSE < 1 && opr->is_single_fpu()) {

     LIR_Opr result = new_register(T_FLOAT);

     set_vreg_flag(result, must_start_in_memory);

     assert(opr->is_register(), "only a register can be spilled");

     assert(opr->value_type()->is_float(), "rounding only for floats available");

     __ roundfp(opr, LIR_OprFact::illegalOpr, result);

     return result;

   }

   return opr;

 }

 LIR_Opr LIRGenerator::force_to_spill(LIR_Opr value, BasicType t) {

   assert(type2size[t] == type2size[value->type()],

          err_msg_res("size mismatch: t=%s, value->type()=%s", type2name(t), type2name(value->type())));

   if (!value->is_register()) {

     // force into a register

     LIR_Opr r = new_register(value->type());

     __ move(value, r);

     value = r;

   }

   // create a spill location

   LIR_Opr tmp = new_register(t);

   set_vreg_flag(tmp, LIRGenerator::must_start_in_memory);

   // move from register to spill

   __ move(value, tmp);

   return tmp;

 }

 void LIRGenerator::profile_branch(If* if_instr, If::Condition cond) {

   if (if_instr->should_profile()) {

     ciMethod* method = if_instr->profiled_method();

     assert(method != NULL, "method should be set if branch is profiled");

     ciMethodData* md = method->method_data_or_null();

     assert(md != NULL, "Sanity");

     ciProfileData* data = md->bci_to_data(if_instr->profiled_bci());

     assert(data != NULL, "must have profiling data");

     assert(data->is_BranchData(), "need BranchData for two-way branches");

     int taken_count_offset     = md->byte_offset_of_slot(data, BranchData::taken_offset());

     int not_taken_count_offset = md->byte_offset_of_slot(data, BranchData::not_taken_offset());

     if (if_instr->is_swapped()) {

       int t = taken_count_offset;

       taken_count_offset = not_taken_count_offset;

       not_taken_count_offset = t;

     }

     LIR_Opr md_reg = new_register(T_METADATA);

     __ metadata2reg(md->constant_encoding(), md_reg);

     LIR_Opr data_offset_reg = new_pointer_register();

     __ cmove(lir_cond(cond),

              LIR_OprFact::intptrConst(taken_count_offset),

              LIR_OprFact::intptrConst(not_taken_count_offset),

              data_offset_reg, as_BasicType(if_instr->x()->type()));

     // MDO cells are intptr_t, so the data_reg width is arch-dependent.

     LIR_Opr data_reg = new_pointer_register();

     LIR_Address* data_addr = new LIR_Address(md_reg, data_offset_reg, data_reg->type());

     __ move(data_addr, data_reg);

     // Use leal instead of add to avoid destroying condition codes on x86

     LIR_Address* fake_incr_value = new LIR_Address(data_reg, DataLayout::counter_increment, T_INT);

     __ leal(LIR_OprFact::address(fake_incr_value), data_reg);

     __ move(data_reg, data_addr);

   }

 }

 // Phi technique:

 // This is about passing live values from one basic block to the other.

 // In code generated with Java it is rather rare that more than one

 // value is on the stack from one basic block to the other.

 // We optimize our technique for efficient passing of one value

 // (of type long, int, double..) but it can be extended.

 // When entering or leaving a basic block, all registers and all spill

 // slots are release and empty. We use the released registers

 // and spill slots to pass the live values from one block

 // to the other. The topmost value, i.e., the value on TOS of expression

 // stack is passed in registers. All other values are stored in spilling

 // area. Every Phi has an index which designates its spill slot

 // At exit of a basic block, we fill the register(s) and spill slots.

 // At entry of a basic block, the block_prolog sets up the content of phi nodes

 // and locks necessary registers and spilling slots.

 // move current value to referenced phi function

 void LIRGenerator::move_to_phi(PhiResolver* resolver, Value cur_val, Value sux_val) {

   Phi* phi = sux_val->as_Phi();

   // cur_val can be null without phi being null in conjunction with inlining

   if (phi != NULL && cur_val != NULL && cur_val != phi && !phi->is_illegal()) {

     LIR_Opr operand = cur_val->operand();

     if (cur_val->operand()->is_illegal()) {

       assert(cur_val->as_Constant() != NULL || cur_val->as_Local() != NULL,

              "these can be produced lazily");

       operand = operand_for_instruction(cur_val);

     }

     resolver->move(operand, operand_for_instruction(phi));

   }

 }

 // Moves all stack values into their PHI position

 void LIRGenerator::move_to_phi(ValueStack* cur_state) {

   BlockBegin* bb = block();

   if (bb->number_of_sux() == 1) {

     BlockBegin* sux = bb->sux_at(0);

     assert(sux->number_of_preds() > 0, "invalid CFG");

     // a block with only one predecessor never has phi functions

     if (sux->number_of_preds() > 1) {

       int max_phis = cur_state->stack_size() + cur_state->locals_size();

       PhiResolver resolver(this, _virtual_register_number + max_phis * 2);

       ValueStack* sux_state = sux->state();

       Value sux_value;

       int index;

       assert(cur_state->scope() == sux_state->scope(), "not matching");

       assert(cur_state->locals_size() == sux_state->locals_size(), "not matching");

       assert(cur_state->stack_size() == sux_state->stack_size(), "not matching");

       for_each_stack_value(sux_state, index, sux_value) {

         move_to_phi(&resolver, cur_state->stack_at(index), sux_value);

       }

       for_each_local_value(sux_state, index, sux_value) {

         move_to_phi(&resolver, cur_state->local_at(index), sux_value);

       }

       assert(cur_state->caller_state() == sux_state->caller_state(), "caller states must be equal");

     }

   }

 }

 LIR_Opr LIRGenerator::new_register(BasicType type) {

   int vreg = _virtual_register_number;

   // add a little fudge factor for the bailout, since the bailout is

   // only checked periodically.  This gives a few extra registers to

   // hand out before we really run out, which helps us keep from

   // tripping over assertions.

   if (vreg + 20 >= LIR_OprDesc::vreg_max) {

     bailout("out of virtual registers");

     if (vreg + 2 >= LIR_OprDesc::vreg_max) {

       // wrap it around

       _virtual_register_number = LIR_OprDesc::vreg_base;

     }

   }

   _virtual_register_number += 1;

   return LIR_OprFact::virtual_register(vreg, type);

 }

 // Try to lock using register in hint

 LIR_Opr LIRGenerator::rlock(Value instr) {

   return new_register(instr->type());

 }

 // does an rlock and sets result

 LIR_Opr LIRGenerator::rlock_result(Value x) {

   LIR_Opr reg = rlock(x);

   set_result(x, reg);

   return reg;

 }

 // does an rlock and sets result

 LIR_Opr LIRGenerator::rlock_result(Value x, BasicType type) {

   LIR_Opr reg;

   switch (type) {

   case T_BYTE:

   case T_BOOLEAN:

     reg = rlock_byte(type);

     break;

   default:

     reg = rlock(x);

     break;

   }

   set_result(x, reg);

   return reg;

 }

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

 ciObject* LIRGenerator::get_jobject_constant(Value value) {

   ObjectType* oc = value->type()->as_ObjectType();

   if (oc) {

     return oc->constant_value();

   }

   return NULL;

 }

 void LIRGenerator::do_ExceptionObject(ExceptionObject* x) {

   assert(block()->is_set(BlockBegin::exception_entry_flag), "ExceptionObject only allowed in exception handler block");

   assert(block()->next() == x, "ExceptionObject must be first instruction of block");

   // no moves are created for phi functions at the begin of exception

   // handlers, so assign operands manually here

   for_each_phi_fun(block(), phi,

                    operand_for_instruction(phi));

   LIR_Opr thread_reg = getThreadPointer();

   __ move_wide(new LIR_Address(thread_reg, in_bytes(JavaThread::exception_oop_offset()), T_OBJECT),

                exceptionOopOpr());

   __ move_wide(LIR_OprFact::oopConst(NULL),

                new LIR_Address(thread_reg, in_bytes(JavaThread::exception_oop_offset()), T_OBJECT));

   __ move_wide(LIR_OprFact::oopConst(NULL),

                new LIR_Address(thread_reg, in_bytes(JavaThread::exception_pc_offset()), T_OBJECT));

   LIR_Opr result = new_register(T_OBJECT);

   __ move(exceptionOopOpr(), result);

   set_result(x, result);

 }

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

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

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

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

 //                        visitor functions

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

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

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

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

 void LIRGenerator::do_Phi(Phi* x) {

   // phi functions are never visited directly

   ShouldNotReachHere();

 }

 // Code for a constant is generated lazily unless the constant is frequently used and can't be inlined.

 void LIRGenerator::do_Constant(Constant* x) {

   if (x->state_before() != NULL) {

     // Any constant with a ValueStack requires patching so emit the patch here

     LIR_Opr reg = rlock_result(x);

     CodeEmitInfo* info = state_for(x, x->state_before());

     __ oop2reg_patch(NULL, reg, info);

   } else if (x->use_count() > 1 && !can_inline_as_constant(x)) {

     if (!x->is_pinned()) {

       // unpinned constants are handled specially so that they can be

       // put into registers when they are used multiple times within a

       // block.  After the block completes their operand will be

       // cleared so that other blocks can't refer to that register.

       set_result(x, load_constant(x));

     } else {

       LIR_Opr res = x->operand();

       if (!res->is_valid()) {

         res = LIR_OprFact::value_type(x->type());

       }

       if (res->is_constant()) {

         LIR_Opr reg = rlock_result(x);

         __ move(res, reg);

       } else {

         set_result(x, res);

       }

     }

   } else {

     set_result(x, LIR_OprFact::value_type(x->type()));

   }

 }

 void LIRGenerator::do_Local(Local* x) {

   // operand_for_instruction has the side effect of setting the result

   // so there's no need to do it here.

   operand_for_instruction(x);

 }

 void LIRGenerator::do_IfInstanceOf(IfInstanceOf* x) {

   Unimplemented();

 }

 void LIRGenerator::do_Return(Return* x) {

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

     BasicTypeList signature;

     signature.append(LP64_ONLY(T_LONG) NOT_LP64(T_INT));    // thread

     signature.append(T_OBJECT); // Method*

     LIR_OprList* args = new LIR_OprList();

     args->append(getThreadPointer());

     LIR_Opr meth = new_register(T_METADATA);

     __ metadata2reg(method()->constant_encoding(), meth);

     args->append(meth);

     call_runtime(&signature, args, CAST_FROM_FN_PTR(address, SharedRuntime::dtrace_method_exit), voidType, NULL);

   }

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

     __ return_op(LIR_OprFact::illegalOpr);

   } else {

     LIR_Opr reg = result_register_for(x->type(), /*callee=*/true);

     LIRItem result(x->result(), this);

     result.load_item_force(reg);

     __ return_op(result.result());

   }

   set_no_result(x);

 }

 // Examble: ref.get()

 // Combination of LoadField and g1 pre-write barrier

 void LIRGenerator::do_Reference_get(Intrinsic* x) {

   const int referent_offset = java_lang_ref_Reference::referent_offset;

   guarantee(referent_offset > 0, "referent offset not initialized");

   assert(x->number_of_arguments() == 1, "wrong type");

   LIRItem reference(x->argument_at(0), this);

   reference.load_item();

   // need to perform the null check on the reference objecy

   CodeEmitInfo* info = NULL;

   if (x->needs_null_check()) {

     info = state_for(x);

   }

   LIR_Address* referent_field_adr =

     new LIR_Address(reference.result(), referent_offset, T_OBJECT);

   LIR_Opr result = rlock_result(x);

   __ load(referent_field_adr, result, info);

   // Register the value in the referent field with the pre-barrier

   pre_barrier(LIR_OprFact::illegalOpr /* addr_opr */,

               result /* pre_val */,

               false  /* do_load */,

               false  /* patch */,

               NULL   /* info */);

 }

 // Example: clazz.isInstance(object)

 void LIRGenerator::do_isInstance(Intrinsic* x) {

   assert(x->number_of_arguments() == 2, "wrong type");

   // TODO could try to substitute this node with an equivalent InstanceOf

   // if clazz is known to be a constant Class. This will pick up newly found

   // constants after HIR construction. I'll leave this to a future change.

   // as a first cut, make a simple leaf call to runtime to stay platform independent.

   // could follow the aastore example in a future change.

   LIRItem clazz(x->argument_at(0), this);

   LIRItem object(x->argument_at(1), this);

   clazz.load_item();

   object.load_item();

   LIR_Opr result = rlock_result(x);

   // need to perform null check on clazz

   if (x->needs_null_check()) {

     CodeEmitInfo* info = state_for(x);

     __ null_check(clazz.result(), info);

   }

   LIR_Opr call_result = call_runtime(clazz.value(), object.value(),

                                      CAST_FROM_FN_PTR(address, Runtime1::is_instance_of),

                                      x->type(),

                                      NULL); // NULL CodeEmitInfo results in a leaf call

   __ move(call_result, result);

 }

 // Example: object.getClass ()

 void LIRGenerator::do_getClass(Intrinsic* x) {

   assert(x->number_of_arguments() == 1, "wrong type");

   LIRItem rcvr(x->argument_at(0), this);

   rcvr.load_item();

   LIR_Opr result = rlock_result(x);

   // need to perform the null check on the rcvr

   CodeEmitInfo* info = NULL;

   if (x->needs_null_check()) {

     info = state_for(x);

   }

   __ move(new LIR_Address(rcvr.result(), oopDesc::klass_offset_in_bytes(), T_ADDRESS), result, info);

   __ move_wide(new LIR_Address(result, in_bytes(Klass::java_mirror_offset()), T_OBJECT), result);

 }

 // Example: Thread.currentThread()

 void LIRGenerator::do_currentThread(Intrinsic* x) {

   assert(x->number_of_arguments() == 0, "wrong type");

   LIR_Opr reg = rlock_result(x);

   __ move_wide(new LIR_Address(getThreadPointer(), in_bytes(JavaThread::threadObj_offset()), T_OBJECT), reg);

 }

 void LIRGenerator::do_RegisterFinalizer(Intrinsic* x) {

   assert(x->number_of_arguments() == 1, "wrong type");

   LIRItem receiver(x->argument_at(0), this);

   receiver.load_item();

   BasicTypeList signature;

   signature.append(T_OBJECT); // receiver

   LIR_OprList* args = new LIR_OprList();

   args->append(receiver.result());

   CodeEmitInfo* info = state_for(x, x->state());

   call_runtime(&signature, args,

                CAST_FROM_FN_PTR(address, Runtime1::entry_for(Runtime1::register_finalizer_id)),

                voidType, info);

   set_no_result(x);

 }

 //------------------------local access--------------------------------------

 LIR_Opr LIRGenerator::operand_for_instruction(Instruction* x) {

   if (x->operand()->is_illegal()) {

     Constant* c = x->as_Constant();

     if (c != NULL) {

       x->set_operand(LIR_OprFact::value_type(c->type()));

     } else {

       assert(x->as_Phi() || x->as_Local() != NULL, "only for Phi and Local");

       // allocate a virtual register for this local or phi

       x->set_operand(rlock(x));

       _instruction_for_operand.at_put_grow(x->operand()->vreg_number(), x, NULL);

     }

   }

   return x->operand();

 }

 Instruction* LIRGenerator::instruction_for_opr(LIR_Opr opr) {

   if (opr->is_virtual()) {

     return instruction_for_vreg(opr->vreg_number());

   }

   return NULL;

 }

 Instruction* LIRGenerator::instruction_for_vreg(int reg_num) {

   if (reg_num < _instruction_for_operand.length()) {

     return _instruction_for_operand.at(reg_num);

   }

   return NULL;

 }

 void LIRGenerator::set_vreg_flag(int vreg_num, VregFlag f) {

   if (_vreg_flags.size_in_bits() == 0) {

     BitMap2D temp(100, num_vreg_flags);

     temp.clear();

     _vreg_flags = temp;

   }

   _vreg_flags.at_put_grow(vreg_num, f, true);

 }

 bool LIRGenerator::is_vreg_flag_set(int vreg_num, VregFlag f) {

   if (!_vreg_flags.is_valid_index(vreg_num, f)) {

     return false;

   }

   return _vreg_flags.at(vreg_num, f);

 }

 // Block local constant handling.  This code is useful for keeping

 // unpinned constants and constants which aren't exposed in the IR in

 // registers.  Unpinned Constant instructions have their operands

 // cleared when the block is finished so that other blocks can't end

 // up referring to their registers.

 LIR_Opr LIRGenerator::load_constant(Constant* x) {

   assert(!x->is_pinned(), "only for unpinned constants");

   _unpinned_constants.append(x);

   return load_constant(LIR_OprFact::value_type(x->type())->as_constant_ptr());

 }

 LIR_Opr LIRGenerator::load_constant(LIR_Const* c) {

   BasicType t = c->type();

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

     LIR_Const* other = _constants.at(i);

     if (t == other->type()) {

       switch (t) {

       case T_INT:

       case T_FLOAT:

         if (c->as_jint_bits() != other->as_jint_bits()) continue;

         break;

       case T_LONG:

       case T_DOUBLE:

         if (c->as_jint_hi_bits() != other->as_jint_hi_bits()) continue;

         if (c->as_jint_lo_bits() != other->as_jint_lo_bits()) continue;

         break;

       case T_OBJECT:

         if (c->as_jobject() != other->as_jobject()) continue;

         break;

       }

       return _reg_for_constants.at(i);

     }

   }

   LIR_Opr result = new_register(t);

   __ move((LIR_Opr)c, result);

   _constants.append(c);

   _reg_for_constants.append(result);

   return result;

 }

 // Various barriers

 void LIRGenerator::pre_barrier(LIR_Opr addr_opr, LIR_Opr pre_val,

                                bool do_load, bool patch, CodeEmitInfo* info) {

   // Do the pre-write barrier, if any.

   switch (_bs->kind()) {

 #if INCLUDE_ALL_GCS

     case BarrierSet::G1SATBCT:

     case BarrierSet::G1SATBCTLogging:

       G1SATBCardTableModRef_pre_barrier(addr_opr, pre_val, do_load, patch, info);

       break;

 #endif // INCLUDE_ALL_GCS

     case BarrierSet::CardTableModRef:

     case BarrierSet::CardTableExtension:

       // No pre barriers

       break;

     case BarrierSet::ModRef:

     case BarrierSet::Other:

       // No pre barriers

       break;

     default      :

       ShouldNotReachHere();

   }

 }

 void LIRGenerator::post_barrier(LIR_OprDesc* addr, LIR_OprDesc* new_val) {

   switch (_bs->kind()) {

 #if INCLUDE_ALL_GCS

     case BarrierSet::G1SATBCT:

     case BarrierSet::G1SATBCTLogging:

       G1SATBCardTableModRef_post_barrier(addr,  new_val);

       break;

 #endif // INCLUDE_ALL_GCS

     case BarrierSet::CardTableModRef:

     case BarrierSet::CardTableExtension:

       CardTableModRef_post_barrier(addr,  new_val);

       break;

     case BarrierSet::ModRef:

     case BarrierSet::Other:

       // No post barriers

       break;

     default      :

       ShouldNotReachHere();

     }

 }

 ////////////////////////////////////////////////////////////////////////

 #if INCLUDE_ALL_GCS

 void LIRGenerator::G1SATBCardTableModRef_pre_barrier(LIR_Opr addr_opr, LIR_Opr pre_val,

                                                      bool do_load, bool patch, CodeEmitInfo* info) {

   // First we test whether marking is in progress.

   BasicType flag_type;

   if (in_bytes(PtrQueue::byte_width_of_active()) == 4) {

     flag_type = T_INT;

   } else {

     guarantee(in_bytes(PtrQueue::byte_width_of_active()) == 1,

               "Assumption");

     flag_type = T_BYTE;

   }

   LIR_Opr thrd = getThreadPointer();

   LIR_Address* mark_active_flag_addr =

     new LIR_Address(thrd,

                     in_bytes(JavaThread::satb_mark_queue_offset() +

                              PtrQueue::byte_offset_of_active()),

                     flag_type);

   // Read the marking-in-progress flag.

   LIR_Opr flag_val = new_register(T_INT);

   __ load(mark_active_flag_addr, flag_val);

   __ cmp(lir_cond_notEqual, flag_val, LIR_OprFact::intConst(0));

   LIR_PatchCode pre_val_patch_code = lir_patch_none;

   CodeStub* slow;

   if (do_load) {

     assert(pre_val == LIR_OprFact::illegalOpr, "sanity");

     assert(addr_opr != LIR_OprFact::illegalOpr, "sanity");

     if (patch)

       pre_val_patch_code = lir_patch_normal;

     pre_val = new_register(T_OBJECT);

     if (!addr_opr->is_address()) {

       assert(addr_opr->is_register(), "must be");

       addr_opr = LIR_OprFact::address(new LIR_Address(addr_opr, T_OBJECT));

     }

     slow = new G1PreBarrierStub(addr_opr, pre_val, pre_val_patch_code, info);

   } else {

     assert(addr_opr == LIR_OprFact::illegalOpr, "sanity");

     assert(pre_val->is_register(), "must be");

     assert(pre_val->type() == T_OBJECT, "must be an object");

     assert(info == NULL, "sanity");

     slow = new G1PreBarrierStub(pre_val);

   }

   __ branch(lir_cond_notEqual, T_INT, slow);

   __ branch_destination(slow->continuation());

 }

 void LIRGenerator::G1SATBCardTableModRef_post_barrier(LIR_OprDesc* addr, LIR_OprDesc* new_val) {

   // If the "new_val" is a constant NULL, no barrier is necessary.

   if (new_val->is_constant() &&

       new_val->as_constant_ptr()->as_jobject() == NULL) return;

   if (!new_val->is_register()) {

     LIR_Opr new_val_reg = new_register(T_OBJECT);

     if (new_val->is_constant()) {

       __ move(new_val, new_val_reg);

     } else {

       __ leal(new_val, new_val_reg);

     }

     new_val = new_val_reg;

   }

   assert(new_val->is_register(), "must be a register at this point");

   if (addr->is_address()) {

     LIR_Address* address = addr->as_address_ptr();

     LIR_Opr ptr = new_pointer_register();

     if (!address->index()->is_valid() && address->disp() == 0) {

       __ move(address->base(), ptr);

     } else {

       assert(address->disp() != max_jint, "lea doesn't support patched addresses!");

       __ leal(addr, ptr);

     }

     addr = ptr;

   }

   assert(addr->is_register(), "must be a register at this point");

   LIR_Opr xor_res = new_pointer_register();

   LIR_Opr xor_shift_res = new_pointer_register();

   if (TwoOperandLIRForm ) {

     __ move(addr, xor_res);

     __ logical_xor(xor_res, new_val, xor_res);

     __ move(xor_res, xor_shift_res);

     __ unsigned_shift_right(xor_shift_res,

                             LIR_OprFact::intConst(HeapRegion::LogOfHRGrainBytes),

                             xor_shift_res,

                             LIR_OprDesc::illegalOpr());

   } else {

     __ logical_xor(addr, new_val, xor_res);

     __ unsigned_shift_right(xor_res,

                             LIR_OprFact::intConst(HeapRegion::LogOfHRGrainBytes),

                             xor_shift_res,

                             LIR_OprDesc::illegalOpr());

   }

   if (!new_val->is_register()) {

     LIR_Opr new_val_reg = new_register(T_OBJECT);

     __ leal(new_val, new_val_reg);

     new_val = new_val_reg;

   }

   assert(new_val->is_register(), "must be a register at this point");

   __ cmp(lir_cond_notEqual, xor_shift_res, LIR_OprFact::intptrConst(NULL_WORD));

   CodeStub* slow = new G1PostBarrierStub(addr, new_val);

   __ branch(lir_cond_notEqual, LP64_ONLY(T_LONG) NOT_LP64(T_INT), slow);

   __ branch_destination(slow->continuation());

 }

 #endif // INCLUDE_ALL_GCS

 ////////////////////////////////////////////////////////////////////////

 void LIRGenerator::CardTableModRef_post_barrier(LIR_OprDesc* addr, LIR_OprDesc* new_val) {

   assert(sizeof(*((CardTableModRefBS*)_bs)->byte_map_base) == sizeof(jbyte), "adjust this code");

   LIR_Const* card_table_base = new LIR_Const(((CardTableModRefBS*)_bs)->byte_map_base);

   if (addr->is_address()) {

     LIR_Address* address = addr->as_address_ptr();

     // ptr cannot be an object because we use this barrier for array card marks

     // and addr can point in the middle of an array.

     LIR_Opr ptr = new_pointer_register();

     if (!address->index()->is_valid() && address->disp() == 0) {

       __ move(address->base(), ptr);

     } else {

       assert(address->disp() != max_jint, "lea doesn't support patched addresses!");

       __ leal(addr, ptr);

     }

     addr = ptr;

   }

   assert(addr->is_register(), "must be a register at this point");

 #ifdef ARM

   // TODO: ARM - move to platform-dependent code

   LIR_Opr tmp = FrameMap::R14_opr;

   if (VM_Version::supports_movw()) {

     __ move((LIR_Opr)card_table_base, tmp);

   } else {

     __ move(new LIR_Address(FrameMap::Rthread_opr, in_bytes(JavaThread::card_table_base_offset()), T_ADDRESS), tmp);

   }

   CardTableModRefBS* ct = (CardTableModRefBS*)_bs;

   LIR_Address *card_addr = new LIR_Address(tmp, addr, (LIR_Address::Scale) -CardTableModRefBS::card_shift, 0, T_BYTE);

   if(((int)ct->byte_map_base & 0xff) == 0) {

     __ move(tmp, card_addr);

   } else {

     LIR_Opr tmp_zero = new_register(T_INT);

     __ move(LIR_OprFact::intConst(0), tmp_zero);

     __ move(tmp_zero, card_addr);

   }

 #else // ARM

   LIR_Opr tmp = new_pointer_register();

   if (TwoOperandLIRForm) {

     __ move(addr, tmp);

     __ unsigned_shift_right(tmp, CardTableModRefBS::card_shift, tmp);

   } else {

     __ unsigned_shift_right(addr, CardTableModRefBS::card_shift, tmp);

   }

   if (can_inline_as_constant(card_table_base)) {

     __ move(LIR_OprFact::intConst(0),

               new LIR_Address(tmp, card_table_base->as_jint(), T_BYTE));

   } else {

     __ move(LIR_OprFact::intConst(0),

               new LIR_Address(tmp, load_constant(card_table_base),

                               T_BYTE));

   }

 #endif // ARM

 }

 //------------------------field access--------------------------------------

 // Comment copied form templateTable_i486.cpp

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

 // Volatile variables demand their effects be made known to all CPU's in

 // order.  Store buffers on most chips allow reads & writes to reorder; the

 // JMM's ReadAfterWrite.java test fails in -Xint mode without some kind of

 // memory barrier (i.e., it's not sufficient that the interpreter does not

 // reorder volatile references, the hardware also must not reorder them).

 //

 // According to the new Java Memory Model (JMM):

 // (1) All volatiles are serialized wrt to each other.

 // ALSO reads & writes act as aquire & release, so:

 // (2) A read cannot let unrelated NON-volatile memory refs that happen after

 // the read float up to before the read.  It's OK for non-volatile memory refs

 // that happen before the volatile read to float down below it.

 // (3) Similar a volatile write cannot let unrelated NON-volatile memory refs

 // that happen BEFORE the write float down to after the write.  It's OK for

 // non-volatile memory refs that happen after the volatile write to float up

 // before it.

 //

 // We only put in barriers around volatile refs (they are expensive), not

 // _between_ memory refs (that would require us to track the flavor of the

 // previous memory refs).  Requirements (2) and (3) require some barriers

 // before volatile stores and after volatile loads.  These nearly cover

 // requirement (1) but miss the volatile-store-volatile-load case.  This final

 // case is placed after volatile-stores although it could just as well go

 // before volatile-loads.

 void LIRGenerator::do_StoreField(StoreField* x) {

   bool needs_patching = x->needs_patching();

   bool is_volatile = x->field()->is_volatile();

   BasicType field_type = x->field_type();

   bool is_oop = (field_type == T_ARRAY || field_type == T_OBJECT);

   CodeEmitInfo* info = NULL;

   if (needs_patching) {

     assert(x->explicit_null_check() == NULL, "can't fold null check into patching field access");

     info = state_for(x, x->state_before());

   } else if (x->needs_null_check()) {

     NullCheck* nc = x->explicit_null_check();

     if (nc == NULL) {

       info = state_for(x);

     } else {

       info = state_for(nc);

     }

   }

   LIRItem object(x->obj(), this);

   LIRItem value(x->value(),  this);

   object.load_item();

   if (is_volatile || needs_patching) {

     // load item if field is volatile (fewer special cases for volatiles)

     // load item if field not initialized

     // load item if field not constant

     // because of code patching we cannot inline constants

     if (field_type == T_BYTE || field_type == T_BOOLEAN) {

       value.load_byte_item();

     } else  {

       value.load_item();

     }

   } else {

     value.load_for_store(field_type);

   }

   set_no_result(x);

 #ifndef PRODUCT

   if (PrintNotLoaded && needs_patching) {

     tty->print_cr("   ###class not loaded at store_%s bci %d",

                   x->is_static() ?  "static" : "field", x->printable_bci());

   }

 #endif

   if (x->needs_null_check() &&

       (needs_patching ||

        MacroAssembler::needs_explicit_null_check(x->offset()))) {

     // emit an explicit null check because the offset is too large

     __ null_check(object.result(), new CodeEmitInfo(info));

   }

   LIR_Address* address;

   if (needs_patching) {

     // we need to patch the offset in the instruction so don't allow

     // generate_address to try to be smart about emitting the -1.

     // Otherwise the patching code won't know how to find the

     // instruction to patch.

     address = new LIR_Address(object.result(), PATCHED_ADDR, field_type);

   } else {

     address = generate_address(object.result(), x->offset(), field_type);

   }

   if (is_volatile && os::is_MP()) {

     __ membar_release();

   }

   if (is_oop) {

     // Do the pre-write barrier, if any.

     pre_barrier(LIR_OprFact::address(address),

                 LIR_OprFact::illegalOpr /* pre_val */,

                 true /* do_load*/,

                 needs_patching,

                 (info ? new CodeEmitInfo(info) : NULL));

   }

   if (is_volatile && !needs_patching) {

     volatile_field_store(value.result(), address, info);

   } else {

     LIR_PatchCode patch_code = needs_patching ? lir_patch_normal : lir_patch_none;

     __ store(value.result(), address, info, patch_code);

   }

   if (is_oop) {

     // Store to object so mark the card of the header

     post_barrier(object.result(), value.result());

   }

   if (is_volatile && os::is_MP()) {

     __ membar();

   }

 }

 void LIRGenerator::do_LoadField(LoadField* x) {

   bool needs_patching = x->needs_patching();

   bool is_volatile = x->field()->is_volatile();

   BasicType field_type = x->field_type();

   CodeEmitInfo* info = NULL;

   if (needs_patching) {

     assert(x->explicit_null_check() == NULL, "can't fold null check into patching field access");

     info = state_for(x, x->state_before());

   } else if (x->needs_null_check()) {

     NullCheck* nc = x->explicit_null_check();

     if (nc == NULL) {

       info = state_for(x);

     } else {

       info = state_for(nc);

     }

   }

   LIRItem object(x->obj(), this);

   object.load_item();

 #ifndef PRODUCT

   if (PrintNotLoaded && needs_patching) {

     tty->print_cr("   ###class not loaded at load_%s bci %d",

                   x->is_static() ?  "static" : "field", x->printable_bci());

   }

 #endif

   bool stress_deopt = StressLoopInvariantCodeMotion && info && info->deoptimize_on_exception();

   if (x->needs_null_check() &&

       (needs_patching ||

        MacroAssembler::needs_explicit_null_check(x->offset()) ||

        stress_deopt)) {

     LIR_Opr obj = object.result();

     if (stress_deopt) {

       obj = new_register(T_OBJECT);

       __ move(LIR_OprFact::oopConst(NULL), obj);

     }

     // emit an explicit null check because the offset is too large

     __ null_check(obj, new CodeEmitInfo(info));

   }

   LIR_Opr reg = rlock_result(x, field_type);

   LIR_Address* address;

   if (needs_patching) {

     // we need to patch the offset in the instruction so don't allow

     // generate_address to try to be smart about emitting the -1.

     // Otherwise the patching code won't know how to find the

     // instruction to patch.

     address = new LIR_Address(object.result(), PATCHED_ADDR, field_type);

   } else {

     address = generate_address(object.result(), x->offset(), field_type);

   }

   if (is_volatile && !needs_patching) {

     volatile_field_load(address, reg, info);

   } else {

     LIR_PatchCode patch_code = needs_patching ? lir_patch_normal : lir_patch_none;

     __ load(address, reg, info, patch_code);

   }

   if (is_volatile && os::is_MP()) {

     __ membar_acquire();

   }

 }

 //------------------------java.nio.Buffer.checkIndex------------------------

 // int java.nio.Buffer.checkIndex(int)

 void LIRGenerator::do_NIOCheckIndex(Intrinsic* x) {

   // NOTE: by the time we are in checkIndex() we are guaranteed that

   // the buffer is non-null (because checkIndex is package-private and

   // only called from within other methods in the buffer).

   assert(x->number_of_arguments() == 2, "wrong type");

   LIRItem buf  (x->argument_at(0), this);

   LIRItem index(x->argument_at(1), this);

   buf.load_item();

   index.load_item();

   LIR_Opr result = rlock_result(x);

   if (GenerateRangeChecks) {

     CodeEmitInfo* info = state_for(x);

     CodeStub* stub = new RangeCheckStub(info, index.result(), true);

     if (index.result()->is_constant()) {

       cmp_mem_int(lir_cond_belowEqual, buf.result(), java_nio_Buffer::limit_offset(), index.result()->as_jint(), info);

       __ branch(lir_cond_belowEqual, T_INT, stub);

     } else {

       cmp_reg_mem(lir_cond_aboveEqual, index.result(), buf.result(),

                   java_nio_Buffer::limit_offset(), T_INT, info);

       __ branch(lir_cond_aboveEqual, T_INT, stub);

     }

     __ move(index.result(), result);

   } else {

     // Just load the index into the result register

     __ move(index.result(), result);

   }

 }

 //------------------------array access--------------------------------------

 void LIRGenerator::do_ArrayLength(ArrayLength* x) {

   if (x->use_count() == 0 && !x->can_trap()) return;

   LIRItem array(x->array(), this);

   array.load_item();

   LIR_Opr reg = rlock_result(x);

   CodeEmitInfo* info = NULL;

   if (x->needs_null_check()) {

     NullCheck* nc = x->explicit_null_check();

     if (nc == NULL) {

       info = state_for(x);

     } else {

       info = state_for(nc);

     }

     if (StressLoopInvariantCodeMotion && info->deoptimize_on_exception()) {

       LIR_Opr obj = new_register(T_OBJECT);

       __ move(LIR_OprFact::oopConst(NULL), obj);

       __ null_check(obj, new CodeEmitInfo(info));

     }

   }

   __ load(new LIR_Address(array.result(), arrayOopDesc::length_offset_in_bytes(), T_INT), reg, info, lir_patch_none);

 }

 void LIRGenerator::do_LoadIndexed(LoadIndexed* x) {

   bool use_length = x->length() != NULL;

   LIRItem array(x->array(), this);

   LIRItem index(x->index(), this);

   LIRItem length(this);

   bool needs_range_check = x->compute_needs_range_check();

   if (use_length && needs_range_check) {

     length.set_instruction(x->length());

     length.load_item();

   }

   array.load_item();

   if (index.is_constant() && can_inline_as_constant(x->index())) {

     // let it be a constant

     index.dont_load_item();

   } else {

     index.load_item();

   }

   CodeEmitInfo* range_check_info = state_for(x);

   CodeEmitInfo* null_check_info = NULL;

   if (x->needs_null_check()) {

     NullCheck* nc = x->explicit_null_check();

     if (nc != NULL) {

       null_check_info = state_for(nc);

     } else {

       null_check_info = range_check_info;

     }

     if (StressLoopInvariantCodeMotion && null_check_info->deoptimize_on_exception()) {

       LIR_Opr obj = new_register(T_OBJECT);

       __ move(LIR_OprFact::oopConst(NULL), obj);

       __ null_check(obj, new CodeEmitInfo(null_check_info));

     }

   }

   // emit array address setup early so it schedules better

   LIR_Address* array_addr = emit_array_address(array.result(), index.result(), x->elt_type(), false);

   if (GenerateRangeChecks && needs_range_check) {

     if (StressLoopInvariantCodeMotion && range_check_info->deoptimize_on_exception()) {

       __ branch(lir_cond_always, T_ILLEGAL, new RangeCheckStub(range_check_info, index.result()));

     } else if (use_length) {

       // TODO: use a (modified) version of array_range_check that does not require a

       //       constant length to be loaded to a register

       __ cmp(lir_cond_belowEqual, length.result(), index.result());

       __ branch(lir_cond_belowEqual, T_INT, new RangeCheckStub(range_check_info, index.result()));

     } else {

       array_range_check(array.result(), index.result(), null_check_info, range_check_info);

       // The range check performs the null check, so clear it out for the load

       null_check_info = NULL;

     }

   }

   __ move(array_addr, rlock_result(x, x->elt_type()), null_check_info);

 }

 void LIRGenerator::do_NullCheck(NullCheck* x) {

   if (x->can_trap()) {

     LIRItem value(x->obj(), this);

     value.load_item();

     CodeEmitInfo* info = state_for(x);

     __ null_check(value.result(), info);

   }

 }

 void LIRGenerator::do_TypeCast(TypeCast* x) {

   LIRItem value(x->obj(), this);

   value.load_item();

   // the result is the same as from the node we are casting

   set_result(x, value.result());

 }

 void LIRGenerator::do_Throw(Throw* x) {

   LIRItem exception(x->exception(), this);

   exception.load_item();

   set_no_result(x);

   LIR_Opr exception_opr = exception.result();

   CodeEmitInfo* info = state_for(x, x->state());

 #ifndef PRODUCT

   if (PrintC1Statistics) {

     increment_counter(Runtime1::throw_count_address(), T_INT);

   }

 #endif

   // check if the instruction has an xhandler in any of the nested scopes

   bool unwind = false;

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

     // this throw is not inside an xhandler

     unwind = true;

   } else {

     // get some idea of the throw type

     bool type_is_exact = true;

     ciType* throw_type = x->exception()->exact_type();

     if (throw_type == NULL) {

       type_is_exact = false;

       throw_type = x->exception()->declared_type();

     }

     if (throw_type != NULL && throw_type->is_instance_klass()) {

       ciInstanceKlass* throw_klass = (ciInstanceKlass*)throw_type;

       unwind = !x->exception_handlers()->could_catch(throw_klass, type_is_exact);

     }

   }

   // do null check before moving exception oop into fixed register

   // to avoid a fixed interval with an oop during the null check.

   // Use a copy of the CodeEmitInfo because debug information is

   // different for null_check and throw.

   if (GenerateCompilerNullChecks &&

       (x->exception()->as_NewInstance() == NULL && x->exception()->as_ExceptionObject() == NULL)) {

     // if the exception object wasn't created using new then it might be null.

     __ null_check(exception_opr, new CodeEmitInfo(info, x->state()->copy(ValueStack::ExceptionState, x->state()->bci())));

   }

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

     // we need to go through the exception lookup path to get JVMTI

     // notification done

     unwind = false;

   }

   // move exception oop into fixed register

   __ move(exception_opr, exceptionOopOpr());

   if (unwind) {

     __ unwind_exception(exceptionOopOpr());

   } else {

     __ throw_exception(exceptionPcOpr(), exceptionOopOpr(), info);

   }

 }

 void LIRGenerator::do_RoundFP(RoundFP* x) {

   LIRItem input(x->input(), this);

   input.load_item();

   LIR_Opr input_opr = input.result();

   assert(input_opr->is_register(), "why round if value is not in a register?");

   assert(input_opr->is_single_fpu() || input_opr->is_double_fpu(), "input should be floating-point value");

   if (input_opr->is_single_fpu()) {

     set_result(x, round_item(input_opr)); // This code path not currently taken

   } else {

     LIR_Opr result = new_register(T_DOUBLE);

     set_vreg_flag(result, must_start_in_memory);

     __ roundfp(input_opr, LIR_OprFact::illegalOpr, result);

     set_result(x, result);

   }

 }

 void LIRGenerator::do_UnsafeGetRaw(UnsafeGetRaw* x) {

   LIRItem base(x->base(), this);

   LIRItem idx(this);

   base.load_item();

   if (x->has_index()) {

     idx.set_instruction(x->index());

     idx.load_nonconstant();

   }

   LIR_Opr reg = rlock_result(x, x->basic_type());

   int   log2_scale = 0;

   if (x->has_index()) {

     assert(x->index()->type()->tag() == intTag, "should not find non-int index");

     log2_scale = x->log2_scale();

   }

   assert(!x->has_index() || idx.value() == x->index(), "should match");

   LIR_Opr base_op = base.result();

 #ifndef _LP64

   if (x->base()->type()->tag() == longTag) {

     base_op = new_register(T_INT);

     __ convert(Bytecodes::_l2i, base.result(), base_op);

   } else {

     assert(x->base()->type()->tag() == intTag, "must be");

   }

 #endif

   BasicType dst_type = x->basic_type();

   LIR_Opr index_op = idx.result();

   LIR_Address* addr;

   if (index_op->is_constant()) {

     assert(log2_scale == 0, "must not have a scale");

     addr = new LIR_Address(base_op, index_op->as_jint(), dst_type);

   } else {

 #ifdef X86

 #ifdef _LP64

     if (!index_op->is_illegal() && index_op->type() == T_INT) {

       LIR_Opr tmp = new_pointer_register();

       __ convert(Bytecodes::_i2l, index_op, tmp);

       index_op = tmp;

     }

 #endif

     addr = new LIR_Address(base_op, index_op, LIR_Address::Scale(log2_scale), 0, dst_type);

 #elif defined(ARM)

     addr = generate_address(base_op, index_op, log2_scale, 0, dst_type);

 #else

     if (index_op->is_illegal() || log2_scale == 0) {

 #ifdef _LP64

       if (!index_op->is_illegal() && index_op->type() == T_INT) {

         LIR_Opr tmp = new_pointer_register();

         __ convert(Bytecodes::_i2l, index_op, tmp);

         index_op = tmp;

       }

 #endif

       addr = new LIR_Address(base_op, index_op, dst_type);

     } else {

       LIR_Opr tmp = new_pointer_register();

       __ shift_left(index_op, log2_scale, tmp);

       addr = new LIR_Address(base_op, tmp, dst_type);

     }

 #endif

   }

   if (x->may_be_unaligned() && (dst_type == T_LONG || dst_type == T_DOUBLE)) {

     __ unaligned_move(addr, reg);

   } else {

     if (dst_type == T_OBJECT && x->is_wide()) {

       __ move_wide(addr, reg);

     } else {

       __ move(addr, reg);

     }

   }

 }

 void LIRGenerator::do_UnsafePutRaw(UnsafePutRaw* x) {

   int  log2_scale = 0;

   BasicType type = x->basic_type();

   if (x->has_index()) {

     assert(x->index()->type()->tag() == intTag, "should not find non-int index");

     log2_scale = x->log2_scale();

   }

   LIRItem base(x->base(), this);

   LIRItem value(x->value(), this);

   LIRItem idx(this);

   base.load_item();

   if (x->has_index()) {

     idx.set_instruction(x->index());

     idx.load_item();

   }

   if (type == T_BYTE || type == T_BOOLEAN) {

     value.load_byte_item();

   } else {

     value.load_item();

   }

   set_no_result(x);

   LIR_Opr base_op = base.result();

 #ifndef _LP64

   if (x->base()->type()->tag() == longTag) {

     base_op = new_register(T_INT);

     __ convert(Bytecodes::_l2i, base.result(), base_op);

   } else {

     assert(x->base()->type()->tag() == intTag, "must be");

   }

 #endif

   LIR_Opr index_op = idx.result();

   if (log2_scale != 0) {

     // temporary fix (platform dependent code without shift on Intel would be better)

     index_op = new_pointer_register();

 #ifdef _LP64

     if(idx.result()->type() == T_INT) {

       __ convert(Bytecodes::_i2l, idx.result(), index_op);

     } else {

 #endif

       // TODO: ARM also allows embedded shift in the address

       __ move(idx.result(), index_op);

 #ifdef _LP64

     }

 #endif

     __ shift_left(index_op, log2_scale, index_op);

   }

 #ifdef _LP64

   else if(!index_op->is_illegal() && index_op->type() == T_INT) {

     LIR_Opr tmp = new_pointer_register();

     __ convert(Bytecodes::_i2l, index_op, tmp);

     index_op = tmp;

   }

 #endif

   LIR_Address* addr = new LIR_Address(base_op, index_op, x->basic_type());

   __ move(value.result(), addr);

 }

 void LIRGenerator::do_UnsafeGetObject(UnsafeGetObject* x) {

   BasicType type = x->basic_type();

   LIRItem src(x->object(), this);

   LIRItem off(x->offset(), this);

   off.load_item();

   src.load_item();

   LIR_Opr value = rlock_result(x, x->basic_type());

   get_Object_unsafe(value, src.result(), off.result(), type, x->is_volatile());

 #if INCLUDE_ALL_GCS

   // We might be reading the value of the referent field of a

   // Reference object in order to attach it back to the live

   // object graph. If G1 is enabled then we need to record

   // the value that is being returned in an SATB log buffer.

   //

   // We need to generate code similar to the following...

   //

   // if (offset == java_lang_ref_Reference::referent_offset) {

   //   if (src != NULL) {

   //     if (klass(src)->reference_type() != REF_NONE) {

   //       pre_barrier(..., value, ...);

   //     }

   //   }

   // }

   if (UseG1GC && type == T_OBJECT) {

     bool gen_pre_barrier = true;     // Assume we need to generate pre_barrier.

     bool gen_offset_check = true;    // Assume we need to generate the offset guard.

     bool gen_source_check = true;    // Assume we need to check the src object for null.

     bool gen_type_check = true;      // Assume we need to check the reference_type.

     if (off.is_constant()) {

       jlong off_con = (off.type()->is_int() ?

                         (jlong) off.get_jint_constant() :

                         off.get_jlong_constant());

       if (off_con != (jlong) java_lang_ref_Reference::referent_offset) {

         // The constant offset is something other than referent_offset.

         // We can skip generating/checking the remaining guards and

         // skip generation of the code stub.

         gen_pre_barrier = false;

       } else {

         // The constant offset is the same as referent_offset -

         // we do not need to generate a runtime offset check.

         gen_offset_check = false;

       }

     }

     // We don't need to generate stub if the source object is an array

     if (gen_pre_barrier && src.type()->is_array()) {

       gen_pre_barrier = false;

     }

     if (gen_pre_barrier) {

       // We still need to continue with the checks.

       if (src.is_constant()) {

         ciObject* src_con = src.get_jobject_constant();

         if (src_con->is_null_object()) {

           // The constant src object is null - We can skip

           // generating the code stub.

           gen_pre_barrier = false;

         } else {

           // Non-null constant source object. We still have to generate

           // the slow stub - but we don't need to generate the runtime

           // null object check.

           gen_source_check = false;

         }

       }

     }

     if (gen_pre_barrier && !PatchALot) {

       // Can the klass of object be statically determined to be

       // a sub-class of Reference?

       ciType* type = src.value()->declared_type();

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

         if (type->is_subtype_of(compilation()->env()->Reference_klass())) {

           gen_type_check = false;

         } else if (type->is_klass() &&

                    !compilation()->env()->Object_klass()->is_subtype_of(type->as_klass())) {

           // Not Reference and not Object klass.

           gen_pre_barrier = false;

         }

       }

     }

     if (gen_pre_barrier) {

       LabelObj* Lcont = new LabelObj();

       // We can have generate one runtime check here. Let's start with

       // the offset check.

       if (gen_offset_check) {

         // if (offset != referent_offset) -> continue

         // If offset is an int then we can do the comparison with the

         // referent_offset constant; otherwise we need to move

         // referent_offset into a temporary register and generate

         // a reg-reg compare.

         LIR_Opr referent_off;

         if (off.type()->is_int()) {

           referent_off = LIR_OprFact::intConst(java_lang_ref_Reference::referent_offset);

         } else {

           assert(off.type()->is_long(), "what else?");

           referent_off = new_register(T_LONG);

           __ move(LIR_OprFact::longConst(java_lang_ref_Reference::referent_offset), referent_off);

         }

         __ cmp(lir_cond_notEqual, off.result(), referent_off);

         __ branch(lir_cond_notEqual, as_BasicType(off.type()), Lcont->label());

       }

       if (gen_source_check) {

         // offset is a const and equals referent offset

         // if (source == null) -> continue

         __ cmp(lir_cond_equal, src.result(), LIR_OprFact::oopConst(NULL));

         __ branch(lir_cond_equal, T_OBJECT, Lcont->label());

       }

       LIR_Opr src_klass = new_register(T_OBJECT);

       if (gen_type_check) {

         // We have determined that offset == referent_offset && src != null.

         // if (src->_klass->_reference_type == REF_NONE) -> continue

         __ move(new LIR_Address(src.result(), oopDesc::klass_offset_in_bytes(), UseCompressedKlassPointers ? T_OBJECT : T_ADDRESS), src_klass);

         LIR_Address* reference_type_addr = new LIR_Address(src_klass, in_bytes(InstanceKlass::reference_type_offset()), T_BYTE);

         LIR_Opr reference_type = new_register(T_INT);

         __ move(reference_type_addr, reference_type);

         __ cmp(lir_cond_equal, reference_type, LIR_OprFact::intConst(REF_NONE));

         __ branch(lir_cond_equal, T_INT, Lcont->label());

       }

       {

         // We have determined that src->_klass->_reference_type != REF_NONE

         // so register the value in the referent field with the pre-barrier.

         pre_barrier(LIR_OprFact::illegalOpr /* addr_opr */,

                     value  /* pre_val */,

                     false  /* do_load */,

                     false  /* patch */,

                     NULL   /* info */);

       }

       __ branch_destination(Lcont->label());

     }

   }

 #endif // INCLUDE_ALL_GCS

   if (x->is_volatile() && os::is_MP()) __ membar_acquire();

 }

 void LIRGenerator::do_UnsafePutObject(UnsafePutObject* x) {

   BasicType type = x->basic_type();

   LIRItem src(x->object(), this);

   LIRItem off(x->offset(), this);

   LIRItem data(x->value(), this);

   src.load_item();

   if (type == T_BOOLEAN || type == T_BYTE) {

     data.load_byte_item();

   } else {

     data.load_item();

   }

   off.load_item();

   set_no_result(x);

   if (x->is_volatile() && os::is_MP()) __ membar_release();

   put_Object_unsafe(src.result(), off.result(), data.result(), type, x->is_volatile());

   if (x->is_volatile() && os::is_MP()) __ membar();

 }

 void LIRGenerator::do_UnsafePrefetch(UnsafePrefetch* x, bool is_store) {

   LIRItem src(x->object(), this);

   LIRItem off(x->offset(), this);

   src.load_item();

   if (off.is_constant() && can_inline_as_constant(x->offset())) {

     // let it be a constant

     off.dont_load_item();

   } else {

     off.load_item();

   }

   set_no_result(x);

   LIR_Address* addr = generate_address(src.result(), off.result(), 0, 0, T_BYTE);

   __ prefetch(addr, is_store);

 }

 void LIRGenerator::do_UnsafePrefetchRead(UnsafePrefetchRead* x) {

   do_UnsafePrefetch(x, false);

 }

 void LIRGenerator::do_UnsafePrefetchWrite(UnsafePrefetchWrite* x) {

   do_UnsafePrefetch(x, true);

 }

 void LIRGenerator::do_SwitchRanges(SwitchRangeArray* x, LIR_Opr value, BlockBegin* default_sux) {

   int lng = x->length();

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

     SwitchRange* one_range = x->at(i);

     int low_key = one_range->low_key();

     int high_key = one_range->high_key();

     BlockBegin* dest = one_range->sux();

     if (low_key == high_key) {

       __ cmp(lir_cond_equal, value, low_key);

       __ branch(lir_cond_equal, T_INT, dest);

     } else if (high_key - low_key == 1) {

       __ cmp(lir_cond_equal, value, low_key);

       __ branch(lir_cond_equal, T_INT, dest);

       __ cmp(lir_cond_equal, value, high_key);

       __ branch(lir_cond_equal, T_INT, dest);

     } else {

       LabelObj* L = new LabelObj();

       __ cmp(lir_cond_less, value, low_key);

       __ branch(lir_cond_less, T_INT, L->label());

       __ cmp(lir_cond_lessEqual, value, high_key);

       __ branch(lir_cond_lessEqual, T_INT, dest);

       __ branch_destination(L->label());

     }

   }

   __ jump(default_sux);

 }

 SwitchRangeArray* LIRGenerator::create_lookup_ranges(TableSwitch* x) {

   SwitchRangeList* res = new SwitchRangeList();

   int len = x->length();

   if (len > 0) {

     BlockBegin* sux = x->sux_at(0);

     int key = x->lo_key();

     BlockBegin* default_sux = x->default_sux();

     SwitchRange* range = new SwitchRange(key, sux);

     for (int i = 0; i < len; i++, key++) {

       BlockBegin* new_sux = x->sux_at(i);

       if (sux == new_sux) {

         // still in same range

         range->set_high_key(key);

       } else {

         // skip tests which explicitly dispatch to the default

         if (sux != default_sux) {

           res->append(range);

         }

         range = new SwitchRange(key, new_sux);

       }

       sux = new_sux;

     }

     if (res->length() == 0 || res->last() != range)  res->append(range);

   }

   return res;

 }

 // we expect the keys to be sorted by increasing value

 SwitchRangeArray* LIRGenerator::create_lookup_ranges(LookupSwitch* x) {

   SwitchRangeList* res = new SwitchRangeList();

   int len = x->length();

   if (len > 0) {

     BlockBegin* default_sux = x->default_sux();

     int key = x->key_at(0);

     BlockBegin* sux = x->sux_at(0);

     SwitchRange* range = new SwitchRange(key, sux);

     for (int i = 1; i < len; i++) {

       int new_key = x->key_at(i);

       BlockBegin* new_sux = x->sux_at(i);

       if (key+1 == new_key && sux == new_sux) {

         // still in same range

         range->set_high_key(new_key);

       } else {

         // skip tests which explicitly dispatch to the default

         if (range->sux() != default_sux) {

           res->append(range);

         }

         range = new SwitchRange(new_key, new_sux);

       }

       key = new_key;

       sux = new_sux;

     }

     if (res->length() == 0 || res->last() != range)  res->append(range);

   }

   return res;

 }

 void LIRGenerator::do_TableSwitch(TableSwitch* x) {

   LIRItem tag(x->tag(), this);

   tag.load_item();

   set_no_result(x);

   if (x->is_safepoint()) {

     __ safepoint(safepoint_poll_register(), state_for(x, x->state_before()));

   }

   // move values into phi locations

   move_to_phi(x->state());

   int lo_key = x->lo_key();

   int hi_key = x->hi_key();

   int len = x->length();

   LIR_Opr value = tag.result();

   if (UseTableRanges) {

     do_SwitchRanges(create_lookup_ranges(x), value, x->default_sux());

   } else {

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

       __ cmp(lir_cond_equal, value, i + lo_key);

       __ branch(lir_cond_equal, T_INT, x->sux_at(i));

     }

     __ jump(x->default_sux());

   }

 }

 void LIRGenerator::do_LookupSwitch(LookupSwitch* x) {

   LIRItem tag(x->tag(), this);

   tag.load_item();

   set_no_result(x);

   if (x->is_safepoint()) {

     __ safepoint(safepoint_poll_register(), state_for(x, x->state_before()));

   }

   // move values into phi locations

   move_to_phi(x->state());

   LIR_Opr value = tag.result();

   if (UseTableRanges) {

     do_SwitchRanges(create_lookup_ranges(x), value, x->default_sux());

   } else {

     int len = x->length();

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

       __ cmp(lir_cond_equal, value, x->key_at(i));

       __ branch(lir_cond_equal, T_INT, x->sux_at(i));

     }

     __ jump(x->default_sux());

   }

 }

 void LIRGenerator::do_Goto(Goto* x) {

   set_no_result(x);

   if (block()->next()->as_OsrEntry()) {

     // need to free up storage used for OSR entry point

     LIR_Opr osrBuffer = block()->next()->operand();

     BasicTypeList signature;

     signature.append(T_INT);

     CallingConvention* cc = frame_map()->c_calling_convention(&signature);

     __ move(osrBuffer, cc->args()->at(0));

     __ call_runtime_leaf(CAST_FROM_FN_PTR(address, SharedRuntime::OSR_migration_end),

                          getThreadTemp(), LIR_OprFact::illegalOpr, cc->args());

   }

   if (x->is_safepoint()) {

     ValueStack* state = x->state_before() ? x->state_before() : x->state();

     // increment backedge counter if needed

     CodeEmitInfo* info = state_for(x, state);

     increment_backedge_counter(info, x->profiled_bci());

     CodeEmitInfo* safepoint_info = state_for(x, state);

     __ safepoint(safepoint_poll_register(), safepoint_info);

   }

   // Gotos can be folded Ifs, handle this case.

   if (x->should_profile()) {

     ciMethod* method = x->profiled_method();

     assert(method != NULL, "method should be set if branch is profiled");

     ciMethodData* md = method->method_data_or_null();

     assert(md != NULL, "Sanity");

     ciProfileData* data = md->bci_to_data(x->profiled_bci());

     assert(data != NULL, "must have profiling data");

     int offset;

     if (x->direction() == Goto::taken) {

       assert(data->is_BranchData(), "need BranchData for two-way branches");

       offset = md->byte_offset_of_slot(data, BranchData::taken_offset());

     } else if (x->direction() == Goto::not_taken) {

       assert(data->is_BranchData(), "need BranchData for two-way branches");

       offset = md->byte_offset_of_slot(data, BranchData::not_taken_offset());

     } else {

       assert(data->is_JumpData(), "need JumpData for branches");

       offset = md->byte_offset_of_slot(data, JumpData::taken_offset());

     }

     LIR_Opr md_reg = new_register(T_METADATA);

     __ metadata2reg(md->constant_encoding(), md_reg);

     increment_counter(new LIR_Address(md_reg, offset,

                                       NOT_LP64(T_INT) LP64_ONLY(T_LONG)), DataLayout::counter_increment);

   }

   // emit phi-instruction move after safepoint since this simplifies

   // describing the state as the safepoint.

   move_to_phi(x->state());

   __ jump(x->default_sux());

 }

 void LIRGenerator::do_Base(Base* x) {

   __ std_entry(LIR_OprFact::illegalOpr);

   // Emit moves from physical registers / stack slots to virtual registers

   CallingConvention* args = compilation()->frame_map()->incoming_arguments();

   IRScope* irScope = compilation()->hir()->top_scope();

   int java_index = 0;

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

     LIR_Opr src = args->at(i);

     assert(!src->is_illegal(), "check");

     BasicType t = src->type();

     // Types which are smaller than int are passed as int, so

     // correct the type which passed.

     switch (t) {

     case T_BYTE:

     case T_BOOLEAN:

     case T_SHORT:

     case T_CHAR:

       t = T_INT;

       break;

     }

     LIR_Opr dest = new_register(t);

     __ move(src, dest);

     // Assign new location to Local instruction for this local

     Local* local = x->state()->local_at(java_index)->as_Local();

     assert(local != NULL, "Locals for incoming arguments must have been created");

 #ifndef __SOFTFP__

     // The java calling convention passes double as long and float as int.

     assert(as_ValueType(t)->tag() == local->type()->tag(), "check");

 #endif // __SOFTFP__

     local->set_operand(dest);

     _instruction_for_operand.at_put_grow(dest->vreg_number(), local, NULL);

     java_index += type2size[t];

   }

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

     BasicTypeList signature;

     signature.append(LP64_ONLY(T_LONG) NOT_LP64(T_INT));    // thread

     signature.append(T_OBJECT); // Method*

     LIR_OprList* args = new LIR_OprList();

     args->append(getThreadPointer());

     LIR_Opr meth = new_register(T_METADATA);

     __ metadata2reg(method()->constant_encoding(), meth);

     args->append(meth);

     call_runtime(&signature, args, CAST_FROM_FN_PTR(address, SharedRuntime::dtrace_method_entry), voidType, NULL);

   }

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

     LIR_Opr obj;