jdk-sandbox: comparison hotspot/src/share/vm/c1/c1

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-:fd16c54261b3
+:489c9b5090e2
+/*
+* Copyright 2005-2006 Sun Microsystems, Inc.  All Rights Reserved.
+* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+*
+* This code is free software; you can redistribute it and/or modify it
+* under the terms of the GNU General Public License version 2 only, as
+* published by the Free Software Foundation.
+*
+* This code is distributed in the hope that it will be useful, but WITHOUT
+* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+* FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+* version 2 for more details (a copy is included in the LICENSE file that
+* accompanied this code).
+*
+* You should have received a copy of the GNU General Public License version
+* 2 along with this work; if not, write to the Free Software Foundation,
+* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+*
+* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+* CA 95054 USA or visit www.sun.com if you need additional information or
+* have any questions.
+*
+*/
+#include "incls/_precompiled.incl"
+#include "incls/_c1_LinearScan.cpp.incl"
+#ifndef PRODUCT
+static LinearScanStatistic _stat_before_alloc;
+static LinearScanStatistic _stat_after_asign;
+static LinearScanStatistic _stat_final;
+static LinearScanTimers _total_timer;
+// helper macro for short definition of timer
+#define TIME_LINEAR_SCAN(timer_name)  TraceTime _block_timer("", _total_timer.timer(LinearScanTimers::timer_name), TimeLinearScan || TimeEachLinearScan, Verbose);
+// helper macro for short definition of trace-output inside code
+#define TRACE_LINEAR_SCAN(level, code)       \
+if (TraceLinearScanLevel >= level) {       \
+code;                                    \
+}
+#else
+#define TIME_LINEAR_SCAN(timer_name)
+#define TRACE_LINEAR_SCAN(level, code)
+#endif
+// Map BasicType to spill size in 32-bit words, matching VMReg's notion of words
+#ifdef _LP64
+static int type2spill_size[T_CONFLICT+1]={ -1, 0, 0, 0, 1, 1, 1, 2, 1, 1, 1, 2, 2, 2, 0, 1, -1};
+#else
+static int type2spill_size[T_CONFLICT+1]={ -1, 0, 0, 0, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 0, 1, -1};
+#endif
+// Implementation of LinearScan
+LinearScan::LinearScan(IR* ir, LIRGenerator* gen, FrameMap* frame_map)
+: _compilation(ir->compilation())
+, _ir(ir)
+, _gen(gen)
+, _frame_map(frame_map)
+, _num_virtual_regs(gen->max_virtual_register_number())
+, _has_fpu_registers(false)
+, _num_calls(-1)
+, _max_spills(0)
+, _unused_spill_slot(-1)
+, _intervals(0)   // initialized later with correct length
+, _new_intervals_from_allocation(new IntervalList())
+, _sorted_intervals(NULL)
+, _lir_ops(0)     // initialized later with correct length
+, _block_of_op(0) // initialized later with correct length
+, _has_info(0)
+, _has_call(0)
+, _scope_value_cache(0) // initialized later with correct length
+, _interval_in_loop(0, 0) // initialized later with correct length
+, _cached_blocks(*ir->linear_scan_order())
+#ifdef IA32
+, _fpu_stack_allocator(NULL)
+#endif
+{
+// note: to use more than on instance of LinearScan at a time this function call has to
+//       be moved somewhere outside of this constructor:
+Interval::initialize();
+assert(this->ir() != NULL,          "check if valid");
+assert(this->compilation() != NULL, "check if valid");
+assert(this->gen() != NULL,         "check if valid");
+assert(this->frame_map() != NULL,   "check if valid");
+}
+// ********** functions for converting LIR-Operands to register numbers
+//
+// Emulate a flat register file comprising physical integer registers,
+// physical floating-point registers and virtual registers, in that order.
+// Virtual registers already have appropriate numbers, since V0 is
+// the number of physical registers.
+// Returns -1 for hi word if opr is a single word operand.
+//
+// Note: the inverse operation (calculating an operand for register numbers)
+//       is done in calc_operand_for_interval()
+int LinearScan::reg_num(LIR_Opr opr) {
+assert(opr->is_register(), "should not call this otherwise");
+if (opr->is_virtual_register()) {
+assert(opr->vreg_number() >= nof_regs, "found a virtual register with a fixed-register number");
+return opr->vreg_number();
+} else if (opr->is_single_cpu()) {
+return opr->cpu_regnr();
+} else if (opr->is_double_cpu()) {
+return opr->cpu_regnrLo();
+#ifdef IA32
+} else if (opr->is_single_xmm()) {
+return opr->fpu_regnr() + pd_first_xmm_reg;
+} else if (opr->is_double_xmm()) {
+return opr->fpu_regnrLo() + pd_first_xmm_reg;
+#endif
+} else if (opr->is_single_fpu()) {
+return opr->fpu_regnr() + pd_first_fpu_reg;
+} else if (opr->is_double_fpu()) {
+return opr->fpu_regnrLo() + pd_first_fpu_reg;
+} else {
+ShouldNotReachHere();
+}
+}
+int LinearScan::reg_numHi(LIR_Opr opr) {
+assert(opr->is_register(), "should not call this otherwise");
+if (opr->is_virtual_register()) {
+return -1;
+} else if (opr->is_single_cpu()) {
+return -1;
+} else if (opr->is_double_cpu()) {
+return opr->cpu_regnrHi();
+#ifdef IA32
+} else if (opr->is_single_xmm()) {
+return -1;
+} else if (opr->is_double_xmm()) {
+return -1;
+#endif
+} else if (opr->is_single_fpu()) {
+return -1;
+} else if (opr->is_double_fpu()) {
+return opr->fpu_regnrHi() + pd_first_fpu_reg;
+} else {
+ShouldNotReachHere();
+}
+}
+// ********** functions for classification of intervals
+bool LinearScan::is_precolored_interval(const Interval* i) {
+return i->reg_num() < LinearScan::nof_regs;
+}
+bool LinearScan::is_virtual_interval(const Interval* i) {
+return i->reg_num() >= LIR_OprDesc::vreg_base;
+}
+bool LinearScan::is_precolored_cpu_interval(const Interval* i) {
+return i->reg_num() < LinearScan::nof_cpu_regs;
+}
+bool LinearScan::is_virtual_cpu_interval(const Interval* i) {
+return i->reg_num() >= LIR_OprDesc::vreg_base && (i->type() != T_FLOAT && i->type() != T_DOUBLE);
+}
+bool LinearScan::is_precolored_fpu_interval(const Interval* i) {
+return i->reg_num() >= LinearScan::nof_cpu_regs && i->reg_num() < LinearScan::nof_regs;
+}
+bool LinearScan::is_virtual_fpu_interval(const Interval* i) {
+return i->reg_num() >= LIR_OprDesc::vreg_base && (i->type() == T_FLOAT || i->type() == T_DOUBLE);
+}
+bool LinearScan::is_in_fpu_register(const Interval* i) {
+// fixed intervals not needed for FPU stack allocation
+return i->reg_num() >= nof_regs && pd_first_fpu_reg <= i->assigned_reg() && i->assigned_reg() <= pd_last_fpu_reg;
+}
+bool LinearScan::is_oop_interval(const Interval* i) {
+// fixed intervals never contain oops
+return i->reg_num() >= nof_regs && i->type() == T_OBJECT;
+}
+// ********** General helper functions
+// compute next unused stack index that can be used for spilling
+int LinearScan::allocate_spill_slot(bool double_word) {
+int spill_slot;
+if (double_word) {
+if ((_max_spills & 1) == 1) {
+// alignment of double-word values
+// the hole because of the alignment is filled with the next single-word value
+assert(_unused_spill_slot == -1, "wasting a spill slot");
+_unused_spill_slot = _max_spills;
+_max_spills++;
+}
+spill_slot = _max_spills;
+_max_spills += 2;
+} else if (_unused_spill_slot != -1) {
+// re-use hole that was the result of a previous double-word alignment
+spill_slot = _unused_spill_slot;
+_unused_spill_slot = -1;
+} else {
+spill_slot = _max_spills;
+_max_spills++;
+}
+int result = spill_slot + LinearScan::nof_regs + frame_map()->argcount();
+// the class OopMapValue uses only 11 bits for storing the name of the
+// oop location. So a stack slot bigger than 2^11 leads to an overflow
+// that is not reported in product builds. Prevent this by checking the
+// spill slot here (altough this value and the later used location name
+// are slightly different)
+if (result > 2000) {
+bailout("too many stack slots used");
+}
+return result;
+}
+void LinearScan::assign_spill_slot(Interval* it) {
+// assign the canonical spill slot of the parent (if a part of the interval
+// is already spilled) or allocate a new spill slot
+if (it->canonical_spill_slot() >= 0) {
+it->assign_reg(it->canonical_spill_slot());
+} else {
+int spill = allocate_spill_slot(type2spill_size[it->type()] == 2);
+it->set_canonical_spill_slot(spill);
+it->assign_reg(spill);
+}
+}
+void LinearScan::propagate_spill_slots() {
+if (!frame_map()->finalize_frame(max_spills())) {
+bailout("frame too large");
+}
+}
+// create a new interval with a predefined reg_num
+// (only used for parent intervals that are created during the building phase)
+Interval* LinearScan::create_interval(int reg_num) {
+assert(_intervals.at(reg_num) == NULL, "overwriting exisiting interval");
+Interval* interval = new Interval(reg_num);
+_intervals.at_put(reg_num, interval);
+// assign register number for precolored intervals
+if (reg_num < LIR_OprDesc::vreg_base) {
+interval->assign_reg(reg_num);
+}
+return interval;
+}
+// assign a new reg_num to the interval and append it to the list of intervals
+// (only used for child intervals that are created during register allocation)
+void LinearScan::append_interval(Interval* it) {
+it->set_reg_num(_intervals.length());
+_intervals.append(it);
+_new_intervals_from_allocation->append(it);
+}
+// copy the vreg-flags if an interval is split
+void LinearScan::copy_register_flags(Interval* from, Interval* to) {
+if (gen()->is_vreg_flag_set(from->reg_num(), LIRGenerator::byte_reg)) {
+gen()->set_vreg_flag(to->reg_num(), LIRGenerator::byte_reg);
+}
+if (gen()->is_vreg_flag_set(from->reg_num(), LIRGenerator::callee_saved)) {
+gen()->set_vreg_flag(to->reg_num(), LIRGenerator::callee_saved);
+}
+// Note: do not copy the must_start_in_memory flag because it is not necessary for child
+//       intervals (only the very beginning of the interval must be in memory)
+}
+// ********** spill move optimization
+// eliminate moves from register to stack if stack slot is known to be correct
+// called during building of intervals
+void LinearScan::change_spill_definition_pos(Interval* interval, int def_pos) {
+assert(interval->is_split_parent(), "can only be called for split parents");
+switch (interval->spill_state()) {
+case noDefinitionFound:
+assert(interval->spill_definition_pos() == -1, "must no be set before");
+interval->set_spill_definition_pos(def_pos);
+interval->set_spill_state(oneDefinitionFound);
+break;
+case oneDefinitionFound:
+assert(def_pos <= interval->spill_definition_pos(), "positions are processed in reverse order when intervals are created");
+if (def_pos < interval->spill_definition_pos() - 2) {
+// second definition found, so no spill optimization possible for this interval
+interval->set_spill_state(noOptimization);
+} else {
+// two consecutive definitions (because of two-operand LIR form)
+assert(block_of_op_with_id(def_pos) == block_of_op_with_id(interval->spill_definition_pos()), "block must be equal");
+}
+break;
+case noOptimization:
+// nothing to do
+break;
+default:
+assert(false, "other states not allowed at this time");
+}
+}
+// called during register allocation
+void LinearScan::change_spill_state(Interval* interval, int spill_pos) {
+switch (interval->spill_state()) {
+case oneDefinitionFound: {
+int def_loop_depth = block_of_op_with_id(interval->spill_definition_pos())->loop_depth();
+int spill_loop_depth = block_of_op_with_id(spill_pos)->loop_depth();
+if (def_loop_depth < spill_loop_depth) {
+// the loop depth of the spilling position is higher then the loop depth
+// at the definition of the interval -> move write to memory out of loop
+// by storing at definitin of the interval
+interval->set_spill_state(storeAtDefinition);
+} else {
+// the interval is currently spilled only once, so for now there is no
+// reason to store the interval at the definition
+interval->set_spill_state(oneMoveInserted);
+}
+break;
+}
+case oneMoveInserted: {
+// the interval is spilled more then once, so it is better to store it to
+// memory at the definition
+interval->set_spill_state(storeAtDefinition);
+break;
+}
+case storeAtDefinition:
+case startInMemory:
+case noOptimization:
+case noDefinitionFound:
+// nothing to do
+break;
+default:
+assert(false, "other states not allowed at this time");
+}
+}
+bool LinearScan::must_store_at_definition(const Interval* i) {
+return i->is_split_parent() && i->spill_state() == storeAtDefinition;
+}
+// called once before asignment of register numbers
+void LinearScan::eliminate_spill_moves() {
+TIME_LINEAR_SCAN(timer_eliminate_spill_moves);
+TRACE_LINEAR_SCAN(3, tty->print_cr("***** Eliminating unnecessary spill moves"));
+// collect all intervals that must be stored after their definion.
+// the list is sorted by Interval::spill_definition_pos
+Interval* interval;
+Interval* temp_list;
+create_unhandled_lists(&interval, &temp_list, must_store_at_definition, NULL);
+#ifdef ASSERT
+Interval* prev = NULL;
+Interval* temp = interval;
+while (temp != Interval::end()) {
+assert(temp->spill_definition_pos() > 0, "invalid spill definition pos");
+if (prev != NULL) {
+assert(temp->from() >= prev->from(), "intervals not sorted");
+assert(temp->spill_definition_pos() >= prev->spill_definition_pos(), "when intervals are sorted by from, then they must also be sorted by spill_definition_pos");
+}
+assert(temp->canonical_spill_slot() >= LinearScan::nof_regs, "interval has no spill slot assigned");
+assert(temp->spill_definition_pos() >= temp->from(), "invalid order");
+assert(temp->spill_definition_pos() <= temp->from() + 2, "only intervals defined once at their start-pos can be optimized");
+TRACE_LINEAR_SCAN(4, tty->print_cr("interval %d (from %d to %d) must be stored at %d", temp->reg_num(), temp->from(), temp->to(), temp->spill_definition_pos()));
+temp = temp->next();
+}
+#endif
+LIR_InsertionBuffer insertion_buffer;
+int num_blocks = block_count();
+for (int i = 0; i < num_blocks; i++) {
+BlockBegin* block = block_at(i);
+LIR_OpList* instructions = block->lir()->instructions_list();
+int         num_inst = instructions->length();
+bool        has_new = false;
+// iterate all instructions of the block. skip the first because it is always a label
+for (int j = 1; j < num_inst; j++) {
+LIR_Op* op = instructions->at(j);
+int op_id = op->id();
+if (op_id == -1) {
+// remove move from register to stack if the stack slot is guaranteed to be correct.
+// only moves that have been inserted by LinearScan can be removed.
+assert(op->code() == lir_move, "only moves can have a op_id of -1");
+assert(op->as_Op1() != NULL, "move must be LIR_Op1");
+assert(op->as_Op1()->result_opr()->is_virtual(), "LinearScan inserts only moves to virtual registers");
+LIR_Op1* op1 = (LIR_Op1*)op;
+Interval* interval = interval_at(op1->result_opr()->vreg_number());
+if (interval->assigned_reg() >= LinearScan::nof_regs && interval->always_in_memory()) {
+// move target is a stack slot that is always correct, so eliminate instruction
+TRACE_LINEAR_SCAN(4, tty->print_cr("eliminating move from interval %d to %d", op1->in_opr()->vreg_number(), op1->result_opr()->vreg_number()));
+instructions->at_put(j, NULL); // NULL-instructions are deleted by assign_reg_num
+}
+} else {
+// insert move from register to stack just after the beginning of the interval
+assert(interval == Interval::end() || interval->spill_definition_pos() >= op_id, "invalid order");
+assert(interval == Interval::end() || (interval->is_split_parent() && interval->spill_state() == storeAtDefinition), "invalid interval");
+while (interval != Interval::end() && interval->spill_definition_pos() == op_id) {
+if (!has_new) {
+// prepare insertion buffer (appended when all instructions of the block are processed)
+insertion_buffer.init(block->lir());
+has_new = true;
+}
+LIR_Opr from_opr = operand_for_interval(interval);
+LIR_Opr to_opr = canonical_spill_opr(interval);
+assert(from_opr->is_fixed_cpu() || from_opr->is_fixed_fpu(), "from operand must be a register");
+assert(to_opr->is_stack(), "to operand must be a stack slot");
+insertion_buffer.move(j, from_opr, to_opr);
+TRACE_LINEAR_SCAN(4, tty->print_cr("inserting move after definition of interval %d to stack slot %d at op_id %d", interval->reg_num(), interval->canonical_spill_slot() - LinearScan::nof_regs, op_id));
+interval = interval->next();
+}
+}
+} // end of instruction iteration
+if (has_new) {
+block->lir()->append(&insertion_buffer);
+}
+} // end of block iteration
+assert(interval == Interval::end(), "missed an interval");
+}
+// ********** Phase 1: number all instructions in all blocks
+// Compute depth-first and linear scan block orders, and number LIR_Op nodes for linear scan.
+void LinearScan::number_instructions() {
+{
+// dummy-timer to measure the cost of the timer itself
+// (this time is then subtracted from all other timers to get the real value)
+TIME_LINEAR_SCAN(timer_do_nothing);
+}
+TIME_LINEAR_SCAN(timer_number_instructions);
+// Assign IDs to LIR nodes and build a mapping, lir_ops, from ID to LIR_Op node.
+int num_blocks = block_count();
+int num_instructions = 0;
+int i;
+for (i = 0; i < num_blocks; i++) {
+num_instructions += block_at(i)->lir()->instructions_list()->length();
+}
+// initialize with correct length
+_lir_ops = LIR_OpArray(num_instructions);
+_block_of_op = BlockBeginArray(num_instructions);
+int op_id = 0;
+int idx = 0;
+for (i = 0; i < num_blocks; i++) {
+BlockBegin* block = block_at(i);
+block->set_first_lir_instruction_id(op_id);
+LIR_OpList* instructions = block->lir()->instructions_list();
+int num_inst = instructions->length();
+for (int j = 0; j < num_inst; j++) {
+LIR_Op* op = instructions->at(j);
+op->set_id(op_id);
+_lir_ops.at_put(idx, op);
+_block_of_op.at_put(idx, block);
+assert(lir_op_with_id(op_id) == op, "must match");
+idx++;
+op_id += 2; // numbering of lir_ops by two
+}
+block->set_last_lir_instruction_id(op_id - 2);
+}
+assert(idx == num_instructions, "must match");
+assert(idx * 2 == op_id, "must match");
+_has_call = BitMap(num_instructions); _has_call.clear();
+_has_info = BitMap(num_instructions); _has_info.clear();
+}
+// ********** Phase 2: compute local live sets separately for each block
+// (sets live_gen and live_kill for each block)
+void LinearScan::set_live_gen_kill(Value value, LIR_Op* op, BitMap& live_gen, BitMap& live_kill) {
+LIR_Opr opr = value->operand();
+Constant* con = value->as_Constant();
+// check some asumptions about debug information
+assert(!value->type()->is_illegal(), "if this local is used by the interpreter it shouldn't be of indeterminate type");
+assert(con == NULL || opr->is_virtual() || opr->is_constant() || opr->is_illegal(), "asumption: Constant instructions have only constant operands");
+assert(con != NULL || opr->is_virtual(), "asumption: non-Constant instructions have only virtual operands");
+if ((con == NULL || con->is_pinned()) && opr->is_register()) {
+assert(reg_num(opr) == opr->vreg_number() && !is_valid_reg_num(reg_numHi(opr)), "invalid optimization below");
+int reg = opr->vreg_number();
+if (!live_kill.at(reg)) {
+live_gen.set_bit(reg);
+TRACE_LINEAR_SCAN(4, tty->print_cr("  Setting live_gen for value %c%d, LIR op_id %d, register number %d", value->type()->tchar(), value->id(), op->id(), reg));
+}
+}
+}
+void LinearScan::compute_local_live_sets() {
+TIME_LINEAR_SCAN(timer_compute_local_live_sets);
+int  num_blocks = block_count();
+int  live_size = live_set_size();
+bool local_has_fpu_registers = false;
+int  local_num_calls = 0;
+LIR_OpVisitState visitor;
+BitMap2D local_interval_in_loop = BitMap2D(_num_virtual_regs, num_loops());
+local_interval_in_loop.clear();
+// iterate all blocks
+for (int i = 0; i < num_blocks; i++) {
+BlockBegin* block = block_at(i);
+BitMap live_gen(live_size);  live_gen.clear();
+BitMap live_kill(live_size); live_kill.clear();
+if (block->is_set(BlockBegin::exception_entry_flag)) {
+// Phi functions at the begin of an exception handler are
+// implicitly defined (= killed) at the beginning of the block.
+for_each_phi_fun(block, phi,
+live_kill.set_bit(phi->operand()->vreg_number())
+);
+}
+LIR_OpList* instructions = block->lir()->instructions_list();
+int num_inst = instructions->length();
+// iterate all instructions of the block. skip the first because it is always a label
+assert(visitor.no_operands(instructions->at(0)), "first operation must always be a label");
+for (int j = 1; j < num_inst; j++) {
+LIR_Op* op = instructions->at(j);
+// visit operation to collect all operands
+visitor.visit(op);
+if (visitor.has_call()) {
+_has_call.set_bit(op->id() >> 1);
+local_num_calls++;
+}
+if (visitor.info_count() > 0) {
+_has_info.set_bit(op->id() >> 1);
+}
+// iterate input operands of instruction
+int k, n, reg;
+n = visitor.opr_count(LIR_OpVisitState::inputMode);
+for (k = 0; k < n; k++) {
+LIR_Opr opr = visitor.opr_at(LIR_OpVisitState::inputMode, k);
+assert(opr->is_register(), "visitor should only return register operands");
+if (opr->is_virtual_register()) {
+assert(reg_num(opr) == opr->vreg_number() && !is_valid_reg_num(reg_numHi(opr)), "invalid optimization below");
+reg = opr->vreg_number();
+if (!live_kill.at(reg)) {
+live_gen.set_bit(reg);
+TRACE_LINEAR_SCAN(4, tty->print_cr("  Setting live_gen for register %d at instruction %d", reg, op->id()));
+}
+if (block->loop_index() >= 0) {
+local_interval_in_loop.set_bit(reg, block->loop_index());
+}
+local_has_fpu_registers = local_has_fpu_registers || opr->is_virtual_fpu();
+}
+#ifdef ASSERT
+// fixed intervals are never live at block boundaries, so
+// they need not be processed in live sets.
+// this is checked by these assertions to be sure about it.
+// the entry block may have incoming values in registers, which is ok.
+if (!opr->is_virtual_register() && block != ir()->start()) {
+reg = reg_num(opr);
+if (is_processed_reg_num(reg)) {
+assert(live_kill.at(reg), "using fixed register that is not defined in this block");
+}
+reg = reg_numHi(opr);
+if (is_valid_reg_num(reg) && is_processed_reg_num(reg)) {
+assert(live_kill.at(reg), "using fixed register that is not defined in this block");
+}
+}
+#endif
+}
+// Add uses of live locals from interpreter's point of view for proper debug information generation
+n = visitor.info_count();
+for (k = 0; k < n; k++) {
+CodeEmitInfo* info = visitor.info_at(k);
+ValueStack* stack = info->stack();
+for_each_state_value(stack, value,
+set_live_gen_kill(value, op, live_gen, live_kill)
+);
+}
+// iterate temp operands of instruction
+n = visitor.opr_count(LIR_OpVisitState::tempMode);
+for (k = 0; k < n; k++) {
+LIR_Opr opr = visitor.opr_at(LIR_OpVisitState::tempMode, k);
+assert(opr->is_register(), "visitor should only return register operands");
+if (opr->is_virtual_register()) {
+assert(reg_num(opr) == opr->vreg_number() && !is_valid_reg_num(reg_numHi(opr)), "invalid optimization below");
+reg = opr->vreg_number();
+live_kill.set_bit(reg);
+if (block->loop_index() >= 0) {
+local_interval_in_loop.set_bit(reg, block->loop_index());
+}
+local_has_fpu_registers = local_has_fpu_registers || opr->is_virtual_fpu();
+}
+#ifdef ASSERT
+// fixed intervals are never live at block boundaries, so
+// they need not be processed in live sets
+// process them only in debug mode so that this can be checked
+if (!opr->is_virtual_register()) {
+reg = reg_num(opr);
+if (is_processed_reg_num(reg)) {
+live_kill.set_bit(reg_num(opr));
+}
+reg = reg_numHi(opr);
+if (is_valid_reg_num(reg) && is_processed_reg_num(reg)) {
+live_kill.set_bit(reg);
+}
+}
+#endif
+}
+// iterate output operands of instruction
+n = visitor.opr_count(LIR_OpVisitState::outputMode);
+for (k = 0; k < n; k++) {
+LIR_Opr opr = visitor.opr_at(LIR_OpVisitState::outputMode, k);
+assert(opr->is_register(), "visitor should only return register operands");
+if (opr->is_virtual_register()) {
+assert(reg_num(opr) == opr->vreg_number() && !is_valid_reg_num(reg_numHi(opr)), "invalid optimization below");
+reg = opr->vreg_number();
+live_kill.set_bit(reg);
+if (block->loop_index() >= 0) {
+local_interval_in_loop.set_bit(reg, block->loop_index());
+}
+local_has_fpu_registers = local_has_fpu_registers || opr->is_virtual_fpu();
+}
+#ifdef ASSERT
+// fixed intervals are never live at block boundaries, so
+// they need not be processed in live sets
+// process them only in debug mode so that this can be checked
+if (!opr->is_virtual_register()) {
+reg = reg_num(opr);
+if (is_processed_reg_num(reg)) {
+live_kill.set_bit(reg_num(opr));
+}
+reg = reg_numHi(opr);
+if (is_valid_reg_num(reg) && is_processed_reg_num(reg)) {
+live_kill.set_bit(reg);
+}
+}
+#endif
+}
+} // end of instruction iteration
+block->set_live_gen (live_gen);
+block->set_live_kill(live_kill);
+block->set_live_in  (BitMap(live_size)); block->live_in().clear();
+block->set_live_out (BitMap(live_size)); block->live_out().clear();
+TRACE_LINEAR_SCAN(4, tty->print("live_gen  B%d ", block->block_id()); print_bitmap(block->live_gen()));
+TRACE_LINEAR_SCAN(4, tty->print("live_kill B%d ", block->block_id()); print_bitmap(block->live_kill()));
+} // end of block iteration
+// propagate local calculated information into LinearScan object
+_has_fpu_registers = local_has_fpu_registers;
+compilation()->set_has_fpu_code(local_has_fpu_registers);
+_num_calls = local_num_calls;
+_interval_in_loop = local_interval_in_loop;
+}
+// ********** Phase 3: perform a backward dataflow analysis to compute global live sets
+// (sets live_in and live_out for each block)
+void LinearScan::compute_global_live_sets() {
+TIME_LINEAR_SCAN(timer_compute_global_live_sets);
+int  num_blocks = block_count();
+bool change_occurred;
+bool change_occurred_in_block;
+int  iteration_count = 0;
+BitMap live_out(live_set_size()); live_out.clear(); // scratch set for calculations
+// Perform a backward dataflow analysis to compute live_out and live_in for each block.
+// The loop is executed until a fixpoint is reached (no changes in an iteration)
+// Exception handlers must be processed because not all live values are
+// present in the state array, e.g. because of global value numbering
+do {
+change_occurred = false;
+// iterate all blocks in reverse order
+for (int i = num_blocks - 1; i >= 0; i--) {
+BlockBegin* block = block_at(i);
+change_occurred_in_block = false;
+// live_out(block) is the union of live_in(sux), for successors sux of block
+int n = block->number_of_sux();
+int e = block->number_of_exception_handlers();
+if (n + e > 0) {
+// block has successors
+if (n > 0) {
+live_out.set_from(block->sux_at(0)->live_in());
+for (int j = 1; j < n; j++) {
+live_out.set_union(block->sux_at(j)->live_in());
+}
+} else {
+live_out.clear();
+}
+for (int j = 0; j < e; j++) {
+live_out.set_union(block->exception_handler_at(j)->live_in());
+}
+if (!block->live_out().is_same(live_out)) {
+// A change occurred.  Swap the old and new live out sets to avoid copying.
+BitMap temp = block->live_out();
+block->set_live_out(live_out);
+live_out = temp;
+change_occurred = true;
+change_occurred_in_block = true;
+}
+}
+if (iteration_count == 0 || change_occurred_in_block) {
+// live_in(block) is the union of live_gen(block) with (live_out(block) & !live_kill(block))
+// note: live_in has to be computed only in first iteration or if live_out has changed!
+BitMap live_in = block->live_in();
+live_in.set_from(block->live_out());
+live_in.set_difference(block->live_kill());
+live_in.set_union(block->live_gen());
+}
+#ifndef PRODUCT
+if (TraceLinearScanLevel >= 4) {
+char c = ' ';
+if (iteration_count == 0 || change_occurred_in_block) {
+c = '*';
+}
+tty->print("(%d) live_in%c  B%d ", iteration_count, c, block->block_id()); print_bitmap(block->live_in());
+tty->print("(%d) live_out%c B%d ", iteration_count, c, block->block_id()); print_bitmap(block->live_out());
+}
+#endif
+}
+iteration_count++;
+if (change_occurred && iteration_count > 50) {
+BAILOUT("too many iterations in compute_global_live_sets");
+}
+} while (change_occurred);
+#ifdef ASSERT
+// check that fixed intervals are not live at block boundaries
+// (live set must be empty at fixed intervals)
+for (int i = 0; i < num_blocks; i++) {
+BlockBegin* block = block_at(i);
+for (int j = 0; j < LIR_OprDesc::vreg_base; j++) {
+assert(block->live_in().at(j)  == false, "live_in  set of fixed register must be empty");
+assert(block->live_out().at(j) == false, "live_out set of fixed register must be empty");
+assert(block->live_gen().at(j) == false, "live_gen set of fixed register must be empty");
+}
+}
+#endif
+// check that the live_in set of the first block is empty
+BitMap live_in_args(ir()->start()->live_in().size());
+live_in_args.clear();
+if (!ir()->start()->live_in().is_same(live_in_args)) {
+#ifdef ASSERT
+tty->print_cr("Error: live_in set of first block must be empty (when this fails, virtual registers are used before they are defined)");
+tty->print_cr("affected registers:");
+print_bitmap(ir()->start()->live_in());
+// print some additional information to simplify debugging
+for (unsigned int i = 0; i < ir()->start()->live_in().size(); i++) {
+if (ir()->start()->live_in().at(i)) {
+Instruction* instr = gen()->instruction_for_vreg(i);
+tty->print_cr("* vreg %d (HIR instruction %c%d)", i, instr == NULL ? ' ' : instr->type()->tchar(), instr == NULL ? 0 : instr->id());
+for (int j = 0; j < num_blocks; j++) {
+BlockBegin* block = block_at(j);
+if (block->live_gen().at(i)) {
+tty->print_cr("  used in block B%d", block->block_id());
+}
+if (block->live_kill().at(i)) {
+tty->print_cr("  defined in block B%d", block->block_id());
+}
+}
+}
+}
+#endif
+// when this fails, virtual registers are used before they are defined.
+assert(false, "live_in set of first block must be empty");
+// bailout of if this occurs in product mode.
+bailout("live_in set of first block not empty");
+}
+}
+// ********** Phase 4: build intervals
+// (fills the list _intervals)
+void LinearScan::add_use(Value value, int from, int to, IntervalUseKind use_kind) {
+assert(!value->type()->is_illegal(), "if this value is used by the interpreter it shouldn't be of indeterminate type");
+LIR_Opr opr = value->operand();
+Constant* con = value->as_Constant();
+if ((con == NULL || con->is_pinned()) && opr->is_register()) {
+assert(reg_num(opr) == opr->vreg_number() && !is_valid_reg_num(reg_numHi(opr)), "invalid optimization below");
+add_use(opr, from, to, use_kind);
+}
+}
+void LinearScan::add_def(LIR_Opr opr, int def_pos, IntervalUseKind use_kind) {
+TRACE_LINEAR_SCAN(2, tty->print(" def "); opr->print(tty); tty->print_cr(" def_pos %d (%d)", def_pos, use_kind));
+assert(opr->is_register(), "should not be called otherwise");
+if (opr->is_virtual_register()) {
+assert(reg_num(opr) == opr->vreg_number() && !is_valid_reg_num(reg_numHi(opr)), "invalid optimization below");
+add_def(opr->vreg_number(), def_pos, use_kind, opr->type_register());
+} else {
+int reg = reg_num(opr);
+if (is_processed_reg_num(reg)) {
+add_def(reg, def_pos, use_kind, opr->type_register());
+}
+reg = reg_numHi(opr);
+if (is_valid_reg_num(reg) && is_processed_reg_num(reg)) {
+add_def(reg, def_pos, use_kind, opr->type_register());
+}
+}
+}
+void LinearScan::add_use(LIR_Opr opr, int from, int to, IntervalUseKind use_kind) {
+TRACE_LINEAR_SCAN(2, tty->print(" use "); opr->print(tty); tty->print_cr(" from %d to %d (%d)", from, to, use_kind));
+assert(opr->is_register(), "should not be called otherwise");
+if (opr->is_virtual_register()) {
+assert(reg_num(opr) == opr->vreg_number() && !is_valid_reg_num(reg_numHi(opr)), "invalid optimization below");
+add_use(opr->vreg_number(), from, to, use_kind, opr->type_register());
+} else {
+int reg = reg_num(opr);
+if (is_processed_reg_num(reg)) {
+add_use(reg, from, to, use_kind, opr->type_register());
+}
+reg = reg_numHi(opr);
+if (is_valid_reg_num(reg) && is_processed_reg_num(reg)) {
+add_use(reg, from, to, use_kind, opr->type_register());
+}
+}
+}
+void LinearScan::add_temp(LIR_Opr opr, int temp_pos, IntervalUseKind use_kind) {
+TRACE_LINEAR_SCAN(2, tty->print(" temp "); opr->print(tty); tty->print_cr(" temp_pos %d (%d)", temp_pos, use_kind));
+assert(opr->is_register(), "should not be called otherwise");
+if (opr->is_virtual_register()) {
+assert(reg_num(opr) == opr->vreg_number() && !is_valid_reg_num(reg_numHi(opr)), "invalid optimization below");
+add_temp(opr->vreg_number(), temp_pos, use_kind, opr->type_register());
+} else {
+int reg = reg_num(opr);
+if (is_processed_reg_num(reg)) {
+add_temp(reg, temp_pos, use_kind, opr->type_register());
+}
+reg = reg_numHi(opr);
+if (is_valid_reg_num(reg) && is_processed_reg_num(reg)) {
+add_temp(reg, temp_pos, use_kind, opr->type_register());
+}
+}
+}
+void LinearScan::add_def(int reg_num, int def_pos, IntervalUseKind use_kind, BasicType type) {
+Interval* interval = interval_at(reg_num);
+if (interval != NULL) {
+assert(interval->reg_num() == reg_num, "wrong interval");
+if (type != T_ILLEGAL) {
+interval->set_type(type);
+}
+Range* r = interval->first();
+if (r->from() <= def_pos) {
+// Update the starting point (when a range is first created for a use, its
+// start is the beginning of the current block until a def is encountered.)
+r->set_from(def_pos);
+interval->add_use_pos(def_pos, use_kind);
+} else {
+// Dead value - make vacuous interval
+// also add use_kind for dead intervals
+interval->add_range(def_pos, def_pos + 1);
+interval->add_use_pos(def_pos, use_kind);
+TRACE_LINEAR_SCAN(2, tty->print_cr("Warning: def of reg %d at %d occurs without use", reg_num, def_pos));
+}
+} else {
+// Dead value - make vacuous interval
+// also add use_kind for dead intervals
+interval = create_interval(reg_num);
+if (type != T_ILLEGAL) {
+interval->set_type(type);
+}
+interval->add_range(def_pos, def_pos + 1);
+interval->add_use_pos(def_pos, use_kind);
+TRACE_LINEAR_SCAN(2, tty->print_cr("Warning: dead value %d at %d in live intervals", reg_num, def_pos));
+}
+change_spill_definition_pos(interval, def_pos);
+if (use_kind == noUse && interval->spill_state() <= startInMemory) {
+// detection of method-parameters and roundfp-results
+// TODO: move this directly to position where use-kind is computed
+interval->set_spill_state(startInMemory);
+}
+}
+void LinearScan::add_use(int reg_num, int from, int to, IntervalUseKind use_kind, BasicType type) {
+Interval* interval = interval_at(reg_num);
+if (interval == NULL) {
+interval = create_interval(reg_num);
+}
+assert(interval->reg_num() == reg_num, "wrong interval");
+if (type != T_ILLEGAL) {
+interval->set_type(type);
+}
+interval->add_range(from, to);
+interval->add_use_pos(to, use_kind);
+}
+void LinearScan::add_temp(int reg_num, int temp_pos, IntervalUseKind use_kind, BasicType type) {
+Interval* interval = interval_at(reg_num);
+if (interval == NULL) {
+interval = create_interval(reg_num);
+}
+assert(interval->reg_num() == reg_num, "wrong interval");
+if (type != T_ILLEGAL) {
+interval->set_type(type);
+}
+interval->add_range(temp_pos, temp_pos + 1);
+interval->add_use_pos(temp_pos, use_kind);
+}
+// the results of this functions are used for optimizing spilling and reloading
+// if the functions return shouldHaveRegister and the interval is spilled,
+// it is not reloaded to a register.
+IntervalUseKind LinearScan::use_kind_of_output_operand(LIR_Op* op, LIR_Opr opr) {
+if (op->code() == lir_move) {
+assert(op->as_Op1() != NULL, "lir_move must be LIR_Op1");
+LIR_Op1* move = (LIR_Op1*)op;
+LIR_Opr res = move->result_opr();
+bool result_in_memory = res->is_virtual() && gen()->is_vreg_flag_set(res->vreg_number(), LIRGenerator::must_start_in_memory);
+if (result_in_memory) {
+// Begin of an interval with must_start_in_memory set.
+// This interval will always get a stack slot first, so return noUse.
+return noUse;
+} else if (move->in_opr()->is_stack()) {
+// method argument (condition must be equal to handle_method_arguments)
+return noUse;
+} else if (move->in_opr()->is_register() && move->result_opr()->is_register()) {
+// Move from register to register
+if (block_of_op_with_id(op->id())->is_set(BlockBegin::osr_entry_flag)) {
+// special handling of phi-function moves inside osr-entry blocks
+// input operand must have a register instead of output operand (leads to better register allocation)
+return shouldHaveRegister;
+}
+}
+}
+if (opr->is_virtual() &&
+gen()->is_vreg_flag_set(opr->vreg_number(), LIRGenerator::must_start_in_memory)) {
+// result is a stack-slot, so prevent immediate reloading
+return noUse;
+}
+// all other operands require a register
+return mustHaveRegister;
+}
+IntervalUseKind LinearScan::use_kind_of_input_operand(LIR_Op* op, LIR_Opr opr) {
+if (op->code() == lir_move) {
+assert(op->as_Op1() != NULL, "lir_move must be LIR_Op1");
+LIR_Op1* move = (LIR_Op1*)op;
+LIR_Opr res = move->result_opr();
+bool result_in_memory = res->is_virtual() && gen()->is_vreg_flag_set(res->vreg_number(), LIRGenerator::must_start_in_memory);
+if (result_in_memory) {
+// Move to an interval with must_start_in_memory set.
+// To avoid moves from stack to stack (not allowed) force the input operand to a register
+return mustHaveRegister;
+} else if (move->in_opr()->is_register() && move->result_opr()->is_register()) {
+// Move from register to register
+if (block_of_op_with_id(op->id())->is_set(BlockBegin::osr_entry_flag)) {
+// special handling of phi-function moves inside osr-entry blocks
+// input operand must have a register instead of output operand (leads to better register allocation)
+return mustHaveRegister;
+}
+// The input operand is not forced to a register (moves from stack to register are allowed),
+// but it is faster if the input operand is in a register
+return shouldHaveRegister;
+}
+}
+#ifdef IA32
+if (op->code() == lir_cmove) {
+// conditional moves can handle stack operands
+assert(op->result_opr()->is_register(), "result must always be in a register");
+return shouldHaveRegister;
+}
+// optimizations for second input operand of arithmehtic operations on Intel
+// this operand is allowed to be on the stack in some cases
+BasicType opr_type = opr->type_register();
+if (opr_type == T_FLOAT || opr_type == T_DOUBLE) {
+if ((UseSSE == 1 && opr_type == T_FLOAT) || UseSSE >= 2) {
+// SSE float instruction (T_DOUBLE only supported with SSE2)
+switch (op->code()) {
+case lir_cmp:
+case lir_add:
+case lir_sub:
+case lir_mul:
+case lir_div:
+{
+assert(op->as_Op2() != NULL, "must be LIR_Op2");
+LIR_Op2* op2 = (LIR_Op2*)op;
+if (op2->in_opr1() != op2->in_opr2() && op2->in_opr2() == opr) {
+assert((op2->result_opr()->is_register() || op->code() == lir_cmp) && op2->in_opr1()->is_register(), "cannot mark second operand as stack if others are not in register");
+return shouldHaveRegister;
+}
+}
+}
+} else {
+// FPU stack float instruction
+switch (op->code()) {
+case lir_add:
+case lir_sub:
+case lir_mul:
+case lir_div:
+{
+assert(op->as_Op2() != NULL, "must be LIR_Op2");
+LIR_Op2* op2 = (LIR_Op2*)op;
+if (op2->in_opr1() != op2->in_opr2() && op2->in_opr2() == opr) {
+assert((op2->result_opr()->is_register() || op->code() == lir_cmp) && op2->in_opr1()->is_register(), "cannot mark second operand as stack if others are not in register");
+return shouldHaveRegister;
+}
+}
+}
+}
+} else if (opr_type != T_LONG) {
+// integer instruction (note: long operands must always be in register)
+switch (op->code()) {
+case lir_cmp:
+case lir_add:
+case lir_sub:
+case lir_logic_and:
+case lir_logic_or:
+case lir_logic_xor:
+{
+assert(op->as_Op2() != NULL, "must be LIR_Op2");
+LIR_Op2* op2 = (LIR_Op2*)op;
+if (op2->in_opr1() != op2->in_opr2() && op2->in_opr2() == opr) {
+assert((op2->result_opr()->is_register() || op->code() == lir_cmp) && op2->in_opr1()->is_register(), "cannot mark second operand as stack if others are not in register");
+return shouldHaveRegister;
+}
+}
+}
+}
+#endif // IA32
+// all other operands require a register
+return mustHaveRegister;
+}
+void LinearScan::handle_method_arguments(LIR_Op* op) {
+// special handling for method arguments (moves from stack to virtual register):
+// the interval gets no register assigned, but the stack slot.
+// it is split before the first use by the register allocator.
+if (op->code() == lir_move) {
+assert(op->as_Op1() != NULL, "must be LIR_Op1");
+LIR_Op1* move = (LIR_Op1*)op;
+if (move->in_opr()->is_stack()) {
+#ifdef ASSERT
+int arg_size = compilation()->method()->arg_size();
+LIR_Opr o = move->in_opr();
+if (o->is_single_stack()) {
+assert(o->single_stack_ix() >= 0 && o->single_stack_ix() < arg_size, "out of range");
+} else if (o->is_double_stack()) {
+assert(o->double_stack_ix() >= 0 && o->double_stack_ix() < arg_size, "out of range");
+} else {
+ShouldNotReachHere();
+}
+assert(move->id() > 0, "invalid id");
+assert(block_of_op_with_id(move->id())->number_of_preds() == 0, "move from stack must be in first block");
+assert(move->result_opr()->is_virtual(), "result of move must be a virtual register");
+TRACE_LINEAR_SCAN(4, tty->print_cr("found move from stack slot %d to vreg %d", o->is_single_stack() ? o->single_stack_ix() : o->double_stack_ix(), reg_num(move->result_opr())));
+#endif
+Interval* interval = interval_at(reg_num(move->result_opr()));
+int stack_slot = LinearScan::nof_regs + (move->in_opr()->is_single_stack() ? move->in_opr()->single_stack_ix() : move->in_opr()->double_stack_ix());
+interval->set_canonical_spill_slot(stack_slot);
+interval->assign_reg(stack_slot);
+}
+}
+}
+void LinearScan::handle_doubleword_moves(LIR_Op* op) {
+// special handling for doubleword move from memory to register:
+// in this case the registers of the input address and the result
+// registers must not overlap -> add a temp range for the input registers
+if (op->code() == lir_move) {
+assert(op->as_Op1() != NULL, "must be LIR_Op1");
+LIR_Op1* move = (LIR_Op1*)op;
+if (move->result_opr()->is_double_cpu() && move->in_opr()->is_pointer()) {
+LIR_Address* address = move->in_opr()->as_address_ptr();
+if (address != NULL) {
+if (address->base()->is_valid()) {
+add_temp(address->base(), op->id(), noUse);
+}
+if (address->index()->is_valid()) {
+add_temp(address->index(), op->id(), noUse);
+}
+}
+}
+}
+}
+void LinearScan::add_register_hints(LIR_Op* op) {
+switch (op->code()) {
+case lir_move:      // fall through
+case lir_convert: {
+assert(op->as_Op1() != NULL, "lir_move, lir_convert must be LIR_Op1");
+LIR_Op1* move = (LIR_Op1*)op;
+LIR_Opr move_from = move->in_opr();
+LIR_Opr move_to = move->result_opr();
+if (move_to->is_register() && move_from->is_register()) {
+Interval* from = interval_at(reg_num(move_from));
+Interval* to = interval_at(reg_num(move_to));
+if (from != NULL && to != NULL) {
+to->set_register_hint(from);
+TRACE_LINEAR_SCAN(4, tty->print_cr("operation at op_id %d: added hint from interval %d to %d", move->id(), from->reg_num(), to->reg_num()));
+}
+}
+break;
+}
+case lir_cmove: {
+assert(op->as_Op2() != NULL, "lir_cmove must be LIR_Op2");
+LIR_Op2* cmove = (LIR_Op2*)op;
+LIR_Opr move_from = cmove->in_opr1();
+LIR_Opr move_to = cmove->result_opr();
+if (move_to->is_register() && move_from->is_register()) {
+Interval* from = interval_at(reg_num(move_from));
+Interval* to = interval_at(reg_num(move_to));
+if (from != NULL && to != NULL) {
+to->set_register_hint(from);
+TRACE_LINEAR_SCAN(4, tty->print_cr("operation at op_id %d: added hint from interval %d to %d", cmove->id(), from->reg_num(), to->reg_num()));
+}
+}
+break;
+}
+}
+}
+void LinearScan::build_intervals() {
+TIME_LINEAR_SCAN(timer_build_intervals);
+// initialize interval list with expected number of intervals
+// (32 is added to have some space for split children without having to resize the list)
+_intervals = IntervalList(num_virtual_regs() + 32);
+// initialize all slots that are used by build_intervals
+_intervals.at_put_grow(num_virtual_regs() - 1, NULL, NULL);
+// create a list with all caller-save registers (cpu, fpu, xmm)
+// when an instruction is a call, a temp range is created for all these registers
+int num_caller_save_registers = 0;
+int caller_save_registers[LinearScan::nof_regs];
+int i;
+for (i = 0; i < FrameMap::nof_caller_save_cpu_regs; i++) {
+LIR_Opr opr = FrameMap::caller_save_cpu_reg_at(i);
+assert(opr->is_valid() && opr->is_register(), "FrameMap should not return invalid operands");
+assert(reg_numHi(opr) == -1, "missing addition of range for hi-register");
+caller_save_registers[num_caller_save_registers++] = reg_num(opr);
+}
+// temp ranges for fpu registers are only created when the method has
+// virtual fpu operands. Otherwise no allocation for fpu registers is
+// perfomed and so the temp ranges would be useless
+if (has_fpu_registers()) {
+#ifdef IA32
+if (UseSSE < 2) {
+#endif
+for (i = 0; i < FrameMap::nof_caller_save_fpu_regs; i++) {
+LIR_Opr opr = FrameMap::caller_save_fpu_reg_at(i);
+assert(opr->is_valid() && opr->is_register(), "FrameMap should not return invalid operands");
+assert(reg_numHi(opr) == -1, "missing addition of range for hi-register");
+caller_save_registers[num_caller_save_registers++] = reg_num(opr);
+}
+#ifdef IA32
+}
+if (UseSSE > 0) {
+for (i = 0; i < FrameMap::nof_caller_save_xmm_regs; i++) {
+LIR_Opr opr = FrameMap::caller_save_xmm_reg_at(i);
+assert(opr->is_valid() && opr->is_register(), "FrameMap should not return invalid operands");
+assert(reg_numHi(opr) == -1, "missing addition of range for hi-register");
+caller_save_registers[num_caller_save_registers++] = reg_num(opr);
+}
+}
+#endif
+}
+assert(num_caller_save_registers <= LinearScan::nof_regs, "out of bounds");
+LIR_OpVisitState visitor;
+// iterate all blocks in reverse order
+for (i = block_count() - 1; i >= 0; i--) {
+BlockBegin* block = block_at(i);
+LIR_OpList* instructions = block->lir()->instructions_list();
+int         block_from =   block->first_lir_instruction_id();
+int         block_to =     block->last_lir_instruction_id();
+assert(block_from == instructions->at(0)->id(), "must be");
+assert(block_to   == instructions->at(instructions->length() - 1)->id(), "must be");
+// Update intervals for registers live at the end of this block;
+BitMap live = block->live_out();
+int size = live.size();
+for (int number = live.get_next_one_offset(0, size); number < size; number = live.get_next_one_offset(number + 1, size)) {
+assert(live.at(number), "should not stop here otherwise");
+assert(number >= LIR_OprDesc::vreg_base, "fixed intervals must not be live on block bounds");
+TRACE_LINEAR_SCAN(2, tty->print_cr("live in %d to %d", number, block_to + 2));
+add_use(number, block_from, block_to + 2, noUse, T_ILLEGAL);
+// add special use positions for loop-end blocks when the
+// interval is used anywhere inside this loop.  It's possible
+// that the block was part of a non-natural loop, so it might
+// have an invalid loop index.
+if (block->is_set(BlockBegin::linear_scan_loop_end_flag) &&
+block->loop_index() != -1 &&
+is_interval_in_loop(number, block->loop_index())) {
+interval_at(number)->add_use_pos(block_to + 1, loopEndMarker);
+}
+}
+// iterate all instructions of the block in reverse order.
+// skip the first instruction because it is always a label
+// definitions of intervals are processed before uses
+assert(visitor.no_operands(instructions->at(0)), "first operation must always be a label");
+for (int j = instructions->length() - 1; j >= 1; j--) {
+LIR_Op* op = instructions->at(j);
+int op_id = op->id();
+// visit operation to collect all operands
+visitor.visit(op);
+// add a temp range for each register if operation destroys caller-save registers
+if (visitor.has_call()) {
+for (int k = 0; k < num_caller_save_registers; k++) {
+add_temp(caller_save_registers[k], op_id, noUse, T_ILLEGAL);
+}
+TRACE_LINEAR_SCAN(4, tty->print_cr("operation destroys all caller-save registers"));
+}
+// Add any platform dependent temps
+pd_add_temps(op);
+// visit definitions (output and temp operands)
+int k, n;
+n = visitor.opr_count(LIR_OpVisitState::outputMode);
+for (k = 0; k < n; k++) {
+LIR_Opr opr = visitor.opr_at(LIR_OpVisitState::outputMode, k);
+assert(opr->is_register(), "visitor should only return register operands");
+add_def(opr, op_id, use_kind_of_output_operand(op, opr));
+}
+n = visitor.opr_count(LIR_OpVisitState::tempMode);
+for (k = 0; k < n; k++) {
+LIR_Opr opr = visitor.opr_at(LIR_OpVisitState::tempMode, k);
+assert(opr->is_register(), "visitor should only return register operands");
+add_temp(opr, op_id, mustHaveRegister);
+}
+// visit uses (input operands)
+n = visitor.opr_count(LIR_OpVisitState::inputMode);
+for (k = 0; k < n; k++) {
+LIR_Opr opr = visitor.opr_at(LIR_OpVisitState::inputMode, k);
+assert(opr->is_register(), "visitor should only return register operands");
+add_use(opr, block_from, op_id, use_kind_of_input_operand(op, opr));
+}
+// Add uses of live locals from interpreter's point of view for proper
+// debug information generation
+// Treat these operands as temp values (if the life range is extended
+// to a call site, the value would be in a register at the call otherwise)
+n = visitor.info_count();
+for (k = 0; k < n; k++) {
+CodeEmitInfo* info = visitor.info_at(k);
+ValueStack* stack = info->stack();
+for_each_state_value(stack, value,
+add_use(value, block_from, op_id + 1, noUse);
+);
+}
+// special steps for some instructions (especially moves)
+handle_method_arguments(op);
+handle_doubleword_moves(op);
+add_register_hints(op);
+} // end of instruction iteration
+} // end of block iteration
+// add the range [0, 1[ to all fixed intervals
+// -> the register allocator need not handle unhandled fixed intervals
+for (int n = 0; n < LinearScan::nof_regs; n++) {
+Interval* interval = interval_at(n);
+if (interval != NULL) {
+interval->add_range(0, 1);
+}
+}
+}
+// ********** Phase 5: actual register allocation
+int LinearScan::interval_cmp(Interval** a, Interval** b) {
+if (*a != NULL) {
+if (*b != NULL) {
+return (*a)->from() - (*b)->from();
+} else {
+return -1;
+}
+} else {
+if (*b != NULL) {
+return 1;
+} else {
+return 0;
+}
+}
+}
+#ifndef PRODUCT
+bool LinearScan::is_sorted(IntervalArray* intervals) {
+int from = -1;
+int i, j;
+for (i = 0; i < intervals->length(); i ++) {
+Interval* it = intervals->at(i);
+if (it != NULL) {
+if (from > it->from()) {
+assert(false, "");
+return false;
+}
+from = it->from();
+}
+}
+// check in both directions if sorted list and unsorted list contain same intervals
+for (i = 0; i < interval_count(); i++) {
+if (interval_at(i) != NULL) {
+int num_found = 0;
+for (j = 0; j < intervals->length(); j++) {
+if (interval_at(i) == intervals->at(j)) {
+num_found++;
+}
+}
+assert(num_found == 1, "lists do not contain same intervals");
+}
+}
+for (j = 0; j < intervals->length(); j++) {
+int num_found = 0;
+for (i = 0; i < interval_count(); i++) {
+if (interval_at(i) == intervals->at(j)) {
+num_found++;
+}
+}
+assert(num_found == 1, "lists do not contain same intervals");
+}
+return true;
+}
+#endif
+void LinearScan::add_to_list(Interval** first, Interval** prev, Interval* interval) {
+if (*prev != NULL) {
+(*prev)->set_next(interval);
+} else {
+*first = interval;
+}
+*prev = interval;
+}
+void LinearScan::create_unhandled_lists(Interval** list1, Interval** list2, bool (is_list1)(const Interval* i), bool (is_list2)(const Interval* i)) {
+assert(is_sorted(_sorted_intervals), "interval list is not sorted");
+*list1 = *list2 = Interval::end();
+Interval* list1_prev = NULL;
+Interval* list2_prev = NULL;
+Interval* v;
+const int n = _sorted_intervals->length();
+for (int i = 0; i < n; i++) {
+v = _sorted_intervals->at(i);
+if (v == NULL) continue;
+if (is_list1(v)) {
+add_to_list(list1, &list1_prev, v);
+} else if (is_list2 == NULL || is_list2(v)) {
+add_to_list(list2, &list2_prev, v);
+}
+}
+if (list1_prev != NULL) list1_prev->set_next(Interval::end());
+if (list2_prev != NULL) list2_prev->set_next(Interval::end());
+assert(list1_prev == NULL || list1_prev->next() == Interval::end(), "linear list ends not with sentinel");
+assert(list2_prev == NULL || list2_prev->next() == Interval::end(), "linear list ends not with sentinel");
+}
+void LinearScan::sort_intervals_before_allocation() {
+TIME_LINEAR_SCAN(timer_sort_intervals_before);
+IntervalList* unsorted_list = &_intervals;
+int unsorted_len = unsorted_list->length();
+int sorted_len = 0;
+int unsorted_idx;
+int sorted_idx = 0;
+int sorted_from_max = -1;
+// calc number of items for sorted list (sorted list must not contain NULL values)
+for (unsorted_idx = 0; unsorted_idx < unsorted_len; unsorted_idx++) {
+if (unsorted_list->at(unsorted_idx) != NULL) {
+sorted_len++;
+}
+}
+IntervalArray* sorted_list = new IntervalArray(sorted_len);
+// special sorting algorithm: the original interval-list is almost sorted,
+// only some intervals are swapped. So this is much faster than a complete QuickSort
+for (unsorted_idx = 0; unsorted_idx < unsorted_len; unsorted_idx++) {
+Interval* cur_interval = unsorted_list->at(unsorted_idx);
+if (cur_interval != NULL) {
+int cur_from = cur_interval->from();
+if (sorted_from_max <= cur_from) {
+sorted_list->at_put(sorted_idx++, cur_interval);
+sorted_from_max = cur_interval->from();
+} else {
+// the asumption that the intervals are already sorted failed,
+// so this interval must be sorted in manually
+int j;
+for (j = sorted_idx - 1; j >= 0 && cur_from < sorted_list->at(j)->from(); j--) {
+sorted_list->at_put(j + 1, sorted_list->at(j));
+}
+sorted_list->at_put(j + 1, cur_interval);
+sorted_idx++;
+}
+}
+}
+_sorted_intervals = sorted_list;
+}
+void LinearScan::sort_intervals_after_allocation() {
+TIME_LINEAR_SCAN(timer_sort_intervals_after);
+IntervalArray* old_list      = _sorted_intervals;
+IntervalList*  new_list      = _new_intervals_from_allocation;
+int old_len = old_list->length();
+int new_len = new_list->length();
+if (new_len == 0) {
+// no intervals have been added during allocation, so sorted list is already up to date
+return;
+}
+// conventional sort-algorithm for new intervals
+new_list->sort(interval_cmp);
+// merge old and new list (both already sorted) into one combined list
+IntervalArray* combined_list = new IntervalArray(old_len + new_len);
+int old_idx = 0;
+int new_idx = 0;
+while (old_idx + new_idx < old_len + new_len) {
+if (new_idx >= new_len || (old_idx < old_len && old_list->at(old_idx)->from() <= new_list->at(new_idx)->from())) {
+combined_list->at_put(old_idx + new_idx, old_list->at(old_idx));
+old_idx++;
+} else {
+combined_list->at_put(old_idx + new_idx, new_list->at(new_idx));
+new_idx++;
+}
+}
+_sorted_intervals = combined_list;
+}
+void LinearScan::allocate_registers() {
+TIME_LINEAR_SCAN(timer_allocate_registers);
+Interval* precolored_cpu_intervals, *not_precolored_cpu_intervals;
+Interval* precolored_fpu_intervals, *not_precolored_fpu_intervals;
+create_unhandled_lists(&precolored_cpu_intervals, &not_precolored_cpu_intervals, is_precolored_cpu_interval, is_virtual_cpu_interval);
+if (has_fpu_registers()) {
+create_unhandled_lists(&precolored_fpu_intervals, &not_precolored_fpu_intervals, is_precolored_fpu_interval, is_virtual_fpu_interval);
+#ifdef ASSERT
+} else {
+// fpu register allocation is omitted because no virtual fpu registers are present
+// just check this again...
+create_unhandled_lists(&precolored_fpu_intervals, &not_precolored_fpu_intervals, is_precolored_fpu_interval, is_virtual_fpu_interval);
+assert(not_precolored_fpu_intervals == Interval::end(), "missed an uncolored fpu interval");
+#endif
+}
+// allocate cpu registers
+LinearScanWalker cpu_lsw(this, precolored_cpu_intervals, not_precolored_cpu_intervals);
+cpu_lsw.walk();
+cpu_lsw.finish_allocation();
+if (has_fpu_registers()) {
+// allocate fpu registers
+LinearScanWalker fpu_lsw(this, precolored_fpu_intervals, not_precolored_fpu_intervals);
+fpu_lsw.walk();
+fpu_lsw.finish_allocation();
+}
+}
+// ********** Phase 6: resolve data flow
+// (insert moves at edges between blocks if intervals have been split)
+// wrapper for Interval::split_child_at_op_id that performs a bailout in product mode
+// instead of returning NULL
+Interval* LinearScan::split_child_at_op_id(Interval* interval, int op_id, LIR_OpVisitState::OprMode mode) {
+Interval* result = interval->split_child_at_op_id(op_id, mode);
+if (result != NULL) {
+return result;
+}
+assert(false, "must find an interval, but do a clean bailout in product mode");
+result = new Interval(LIR_OprDesc::vreg_base);
+result->assign_reg(0);
+result->set_type(T_INT);
+BAILOUT_("LinearScan: interval is NULL", result);
+}
+Interval* LinearScan::interval_at_block_begin(BlockBegin* block, int reg_num) {
+assert(LinearScan::nof_regs <= reg_num && reg_num < num_virtual_regs(), "register number out of bounds");
+assert(interval_at(reg_num) != NULL, "no interval found");
+return split_child_at_op_id(interval_at(reg_num), block->first_lir_instruction_id(), LIR_OpVisitState::outputMode);
+}
+Interval* LinearScan::interval_at_block_end(BlockBegin* block, int reg_num) {
+assert(LinearScan::nof_regs <= reg_num && reg_num < num_virtual_regs(), "register number out of bounds");
+assert(interval_at(reg_num) != NULL, "no interval found");
+return split_child_at_op_id(interval_at(reg_num), block->last_lir_instruction_id() + 1, LIR_OpVisitState::outputMode);
+}
+Interval* LinearScan::interval_at_op_id(int reg_num, int op_id) {
+assert(LinearScan::nof_regs <= reg_num && reg_num < num_virtual_regs(), "register number out of bounds");
+assert(interval_at(reg_num) != NULL, "no interval found");
+return split_child_at_op_id(interval_at(reg_num), op_id, LIR_OpVisitState::inputMode);
+}
+void LinearScan::resolve_collect_mappings(BlockBegin* from_block, BlockBegin* to_block, MoveResolver &move_resolver) {
+DEBUG_ONLY(move_resolver.check_empty());
+const int num_regs = num_virtual_regs();
+const int size = live_set_size();
+const BitMap live_at_edge = to_block->live_in();
+// visit all registers where the live_at_edge bit is set
+for (int r = live_at_edge.get_next_one_offset(0, size); r < size; r = live_at_edge.get_next_one_offset(r + 1, size)) {
+assert(r < num_regs, "live information set for not exisiting interval");
+assert(from_block->live_out().at(r) && to_block->live_in().at(r), "interval not live at this edge");
+Interval* from_interval = interval_at_block_end(from_block, r);
+Interval* to_interval = interval_at_block_begin(to_block, r);
+if (from_interval != to_interval && (from_interval->assigned_reg() != to_interval->assigned_reg() || from_interval->assigned_regHi() != to_interval->assigned_regHi())) {
+// need to insert move instruction
+move_resolver.add_mapping(from_interval, to_interval);
+}
+}
+}
+void LinearScan::resolve_find_insert_pos(BlockBegin* from_block, BlockBegin* to_block, MoveResolver &move_resolver) {
+if (from_block->number_of_sux() <= 1) {
+TRACE_LINEAR_SCAN(4, tty->print_cr("inserting moves at end of from_block B%d", from_block->block_id()));
+LIR_OpList* instructions = from_block->lir()->instructions_list();
+LIR_OpBranch* branch = instructions->last()->as_OpBranch();
+if (branch != NULL) {
+// insert moves before branch
+assert(branch->cond() == lir_cond_always, "block does not end with an unconditional jump");
+move_resolver.set_insert_position(from_block->lir(), instructions->length() - 2);
+} else {
+move_resolver.set_insert_position(from_block->lir(), instructions->length() - 1);
+}
+} else {
+TRACE_LINEAR_SCAN(4, tty->print_cr("inserting moves at beginning of to_block B%d", to_block->block_id()));
+#ifdef ASSERT
+assert(from_block->lir()->instructions_list()->at(0)->as_OpLabel() != NULL, "block does not start with a label");
+// because the number of predecessor edges matches the number of
+// successor edges, blocks which are reached by switch statements
+// may have be more than one predecessor but it will be guaranteed
+// that all predecessors will be the same.
+for (int i = 0; i < to_block->number_of_preds(); i++) {
+assert(from_block == to_block->pred_at(i), "all critical edges must be broken");
+}
+#endif
+move_resolver.set_insert_position(to_block->lir(), 0);
+}
+}
+// insert necessary moves (spilling or reloading) at edges between blocks if interval has been split
+void LinearScan::resolve_data_flow() {
+TIME_LINEAR_SCAN(timer_resolve_data_flow);
+int num_blocks = block_count();
+MoveResolver move_resolver(this);
+BitMap block_completed(num_blocks);  block_completed.clear();
+BitMap already_resolved(num_blocks); already_resolved.clear();
+int i;
+for (i = 0; i < num_blocks; i++) {
+BlockBegin* block = block_at(i);
+// check if block has only one predecessor and only one successor
+if (block->number_of_preds() == 1 && block->number_of_sux() == 1 && block->number_of_exception_handlers() == 0) {
+LIR_OpList* instructions = block->lir()->instructions_list();
+assert(instructions->at(0)->code() == lir_label, "block must start with label");
+assert(instructions->last()->code() == lir_branch, "block with successors must end with branch");
+assert(instructions->last()->as_OpBranch()->cond() == lir_cond_always, "block with successor must end with unconditional branch");
+// check if block is empty (only label and branch)
+if (instructions->length() == 2) {
+BlockBegin* pred = block->pred_at(0);
+BlockBegin* sux = block->sux_at(0);
+// prevent optimization of two consecutive blocks
+if (!block_completed.at(pred->linear_scan_number()) && !block_completed.at(sux->linear_scan_number())) {
+TRACE_LINEAR_SCAN(3, tty->print_cr("**** optimizing empty block B%d (pred: B%d, sux: B%d)", block->block_id(), pred->block_id(), sux->block_id()));
+block_completed.set_bit(block->linear_scan_number());
+// directly resolve between pred and sux (without looking at the empty block between)
+resolve_collect_mappings(pred, sux, move_resolver);
+if (move_resolver.has_mappings()) {
+move_resolver.set_insert_position(block->lir(), 0);
+move_resolver.resolve_and_append_moves();
+}
+}
+}
+}
+}
+for (i = 0; i < num_blocks; i++) {
+if (!block_completed.at(i)) {
+BlockBegin* from_block = block_at(i);
+already_resolved.set_from(block_completed);
+int num_sux = from_block->number_of_sux();
+for (int s = 0; s < num_sux; s++) {
+BlockBegin* to_block = from_block->sux_at(s);
+// check for duplicate edges between the same blocks (can happen with switch blocks)
+if (!already_resolved.at(to_block->linear_scan_number())) {
+TRACE_LINEAR_SCAN(3, tty->print_cr("**** processing edge between B%d and B%d", from_block->block_id(), to_block->block_id()));
+already_resolved.set_bit(to_block->linear_scan_number());
+// collect all intervals that have been split between from_block and to_block
+resolve_collect_mappings(from_block, to_block, move_resolver);
+if (move_resolver.has_mappings()) {
+resolve_find_insert_pos(from_block, to_block, move_resolver);
+move_resolver.resolve_and_append_moves();
+}
+}
+}
+}
+}
+}
+void LinearScan::resolve_exception_entry(BlockBegin* block, int reg_num, MoveResolver &move_resolver) {
+if (interval_at(reg_num) == NULL) {
+// if a phi function is never used, no interval is created -> ignore this
+return;
+}
+Interval* interval = interval_at_block_begin(block, reg_num);
+int reg = interval->assigned_reg();
+int regHi = interval->assigned_regHi();
+if ((reg < nof_regs && interval->always_in_memory()) ||
+(use_fpu_stack_allocation() && reg >= pd_first_fpu_reg && reg <= pd_last_fpu_reg)) {
+// the interval is split to get a short range that is located on the stack
+// in the following two cases:
+// * the interval started in memory (e.g. method parameter), but is currently in a register
+//   this is an optimization for exception handling that reduces the number of moves that
+//   are necessary for resolving the states when an exception uses this exception handler
+// * the interval would be on the fpu stack at the begin of the exception handler
+//   this is not allowed because of the complicated fpu stack handling on Intel
+// range that will be spilled to memory
+int from_op_id = block->first_lir_instruction_id();
+int to_op_id = from_op_id + 1;  // short live range of length 1
+assert(interval->from() <= from_op_id && interval->to() >= to_op_id,
+"no split allowed between exception entry and first instruction");
+if (interval->from() != from_op_id) {
+// the part before from_op_id is unchanged
+interval = interval->split(from_op_id);
+interval->assign_reg(reg, regHi);
+append_interval(interval);
+}
+assert(interval->from() == from_op_id, "must be true now");
+Interval* spilled_part = interval;
+if (interval->to() != to_op_id) {
+// the part after to_op_id is unchanged
+spilled_part = interval->split_from_start(to_op_id);
+append_interval(spilled_part);
+move_resolver.add_mapping(spilled_part, interval);
+}
+assign_spill_slot(spilled_part);
+assert(spilled_part->from() == from_op_id && spilled_part->to() == to_op_id, "just checking");
+}
+}
+void LinearScan::resolve_exception_entry(BlockBegin* block, MoveResolver &move_resolver) {
+assert(block->is_set(BlockBegin::exception_entry_flag), "should not call otherwise");
+DEBUG_ONLY(move_resolver.check_empty());
+// visit all registers where the live_in bit is set
+int size = live_set_size();
+for (int r = block->live_in().get_next_one_offset(0, size); r < size; r = block->live_in().get_next_one_offset(r + 1, size)) {
+resolve_exception_entry(block, r, move_resolver);
+}
+// the live_in bits are not set for phi functions of the xhandler entry, so iterate them separately
+for_each_phi_fun(block, phi,
+resolve_exception_entry(block, phi->operand()->vreg_number(), move_resolver)
+);
+if (move_resolver.has_mappings()) {
+// insert moves after first instruction
+move_resolver.set_insert_position(block->lir(), 1);
+move_resolver.resolve_and_append_moves();
+}
+}
+void LinearScan::resolve_exception_edge(XHandler* handler, int throwing_op_id, int reg_num, Phi* phi, MoveResolver &move_resolver) {
+if (interval_at(reg_num) == NULL) {
+// if a phi function is never used, no interval is created -> ignore this
+return;
+}
+// the computation of to_interval is equal to resolve_collect_mappings,
+// but from_interval is more complicated because of phi functions
+BlockBegin* to_block = handler->entry_block();
+Interval* to_interval = interval_at_block_begin(to_block, reg_num);
+if (phi != NULL) {
+// phi function of the exception entry block
+// no moves are created for this phi function in the LIR_Generator, so the
+// interval at the throwing instruction must be searched using the operands
+// of the phi function
+Value from_value = phi->operand_at(handler->phi_operand());
+// with phi functions it can happen that the same from_value is used in
+// multiple mappings, so notify move-resolver that this is allowed
+move_resolver.set_multiple_reads_allowed();
+Constant* con = from_value->as_Constant();
+if (con != NULL && !con->is_pinned()) {
+// unpinned constants may have no register, so add mapping from constant to interval
+move_resolver.add_mapping(LIR_OprFact::value_type(con->type()), to_interval);
+} else {
+// search split child at the throwing op_id
+Interval* from_interval = interval_at_op_id(from_value->operand()->vreg_number(), throwing_op_id);
+move_resolver.add_mapping(from_interval, to_interval);
+}
+} else {
+// no phi function, so use reg_num also for from_interval
+// search split child at the throwing op_id
+Interval* from_interval = interval_at_op_id(reg_num, throwing_op_id);
+if (from_interval != to_interval) {
+// optimization to reduce number of moves: when to_interval is on stack and
+// the stack slot is known to be always correct, then no move is necessary
+if (!from_interval->always_in_memory() || from_interval->canonical_spill_slot() != to_interval->assigned_reg()) {
+move_resolver.add_mapping(from_interval, to_interval);
+}
+}
+}
+}
+void LinearScan::resolve_exception_edge(XHandler* handler, int throwing_op_id, MoveResolver &move_resolver) {
+TRACE_LINEAR_SCAN(4, tty->print_cr("resolving exception handler B%d: throwing_op_id=%d", handler->entry_block()->block_id(), throwing_op_id));
+DEBUG_ONLY(move_resolver.check_empty());
+assert(handler->lir_op_id() == -1, "already processed this xhandler");
+DEBUG_ONLY(handler->set_lir_op_id(throwing_op_id));
+assert(handler->entry_code() == NULL, "code already present");
+// visit all registers where the live_in bit is set
+BlockBegin* block = handler->entry_block();
+int size = live_set_size();
+for (int r = block->live_in().get_next_one_offset(0, size); r < size; r = block->live_in().get_next_one_offset(r + 1, size)) {
+resolve_exception_edge(handler, throwing_op_id, r, NULL, move_resolver);
+}
+// the live_in bits are not set for phi functions of the xhandler entry, so iterate them separately
+for_each_phi_fun(block, phi,
+resolve_exception_edge(handler, throwing_op_id, phi->operand()->vreg_number(), phi, move_resolver)
+);
+if (move_resolver.has_mappings()) {
+LIR_List* entry_code = new LIR_List(compilation());
+move_resolver.set_insert_position(entry_code, 0);
+move_resolver.resolve_and_append_moves();
+entry_code->jump(handler->entry_block());
+handler->set_entry_code(entry_code);
+}
+}
+void LinearScan::resolve_exception_handlers() {
+MoveResolver move_resolver(this);
+LIR_OpVisitState visitor;
+int num_blocks = block_count();
+int i;
+for (i = 0; i < num_blocks; i++) {
+BlockBegin* block = block_at(i);
+if (block->is_set(BlockBegin::exception_entry_flag)) {
+resolve_exception_entry(block, move_resolver);
+}
+}
+for (i = 0; i < num_blocks; i++) {
+BlockBegin* block = block_at(i);
+LIR_List* ops = block->lir();
+int num_ops = ops->length();
+// iterate all instructions of the block. skip the first because it is always a label
+assert(visitor.no_operands(ops->at(0)), "first operation must always be a label");
+for (int j = 1; j < num_ops; j++) {
+LIR_Op* op = ops->at(j);
+int op_id = op->id();
+if (op_id != -1 && has_info(op_id)) {
+// visit operation to collect all operands
+visitor.visit(op);
+assert(visitor.info_count() > 0, "should not visit otherwise");
+XHandlers* xhandlers = visitor.all_xhandler();
+int n = xhandlers->length();
+for (int k = 0; k < n; k++) {
+resolve_exception_edge(xhandlers->handler_at(k), op_id, move_resolver);
+}
+#ifdef ASSERT
+} else {
+visitor.visit(op);
+assert(visitor.all_xhandler()->length() == 0, "missed exception handler");
+#endif
+}
+}
+}
+}
+// ********** Phase 7: assign register numbers back to LIR
+// (includes computation of debug information and oop maps)
+VMReg LinearScan::vm_reg_for_interval(Interval* interval) {
+VMReg reg = interval->cached_vm_reg();
+if (!reg->is_valid() ) {
+reg = vm_reg_for_operand(operand_for_interval(interval));
+interval->set_cached_vm_reg(reg);
+}
+assert(reg == vm_reg_for_operand(operand_for_interval(interval)), "wrong cached value");
+return reg;
+}
+VMReg LinearScan::vm_reg_for_operand(LIR_Opr opr) {
+assert(opr->is_oop(), "currently only implemented for oop operands");
+return frame_map()->regname(opr);
+}
+LIR_Opr LinearScan::operand_for_interval(Interval* interval) {
+LIR_Opr opr = interval->cached_opr();
+if (opr->is_illegal()) {
+opr = calc_operand_for_interval(interval);
+interval->set_cached_opr(opr);
+}
+assert(opr == calc_operand_for_interval(interval), "wrong cached value");
+return opr;
+}
+LIR_Opr LinearScan::calc_operand_for_interval(const Interval* interval) {
+int assigned_reg = interval->assigned_reg();
+BasicType type = interval->type();
+if (assigned_reg >= nof_regs) {
+// stack slot
+assert(interval->assigned_regHi() == any_reg, "must not have hi register");
+return LIR_OprFact::stack(assigned_reg - nof_regs, type);
+} else {
+// register
+switch (type) {
+case T_OBJECT: {
+assert(assigned_reg >= pd_first_cpu_reg && assigned_reg <= pd_last_cpu_reg, "no cpu register");
+assert(interval->assigned_regHi() == any_reg, "must not have hi register");
+return LIR_OprFact::single_cpu_oop(assigned_reg);
+}
+case T_INT: {
+assert(assigned_reg >= pd_first_cpu_reg && assigned_reg <= pd_last_cpu_reg, "no cpu register");
+assert(interval->assigned_regHi() == any_reg, "must not have hi register");
+return LIR_OprFact::single_cpu(assigned_reg);
+}
+case T_LONG: {
+int assigned_regHi = interval->assigned_regHi();
+assert(assigned_reg >= pd_first_cpu_reg && assigned_reg <= pd_last_cpu_reg, "no cpu register");
+assert(num_physical_regs(T_LONG) == 1 ||
+(assigned_regHi >= pd_first_cpu_reg && assigned_regHi <= pd_last_cpu_reg), "no cpu register");
+assert(assigned_reg != assigned_regHi, "invalid allocation");
+assert(num_physical_regs(T_LONG) == 1 || assigned_reg < assigned_regHi,
+"register numbers must be sorted (ensure that e.g. a move from eax,ebx to ebx,eax can not occur)");
+assert((assigned_regHi != any_reg) ^ (num_physical_regs(T_LONG) == 1), "must be match");
+if (requires_adjacent_regs(T_LONG)) {
+assert(assigned_reg % 2 == 0 && assigned_reg + 1 == assigned_regHi, "must be sequential and even");
+}
+#ifdef SPARC
+#ifdef _LP64
+return LIR_OprFact::double_cpu(assigned_reg, assigned_reg);
+#else
+return LIR_OprFact::double_cpu(assigned_regHi, assigned_reg);
+#endif
+#else
+return LIR_OprFact::double_cpu(assigned_reg, assigned_regHi);
+#endif
+}
+case T_FLOAT: {
+#ifdef IA32
+if (UseSSE >= 1) {
+assert(assigned_reg >= pd_first_xmm_reg && assigned_reg <= pd_last_xmm_reg, "no xmm register");
+assert(interval->assigned_regHi() == any_reg, "must not have hi register");
+return LIR_OprFact::single_xmm(assigned_reg - pd_first_xmm_reg);
+}
+#endif
+assert(assigned_reg >= pd_first_fpu_reg && assigned_reg <= pd_last_fpu_reg, "no fpu register");
+assert(interval->assigned_regHi() == any_reg, "must not have hi register");
+return LIR_OprFact::single_fpu(assigned_reg - pd_first_fpu_reg);
+}
+case T_DOUBLE: {
+#ifdef IA32
+if (UseSSE >= 2) {
+assert(assigned_reg >= pd_first_xmm_reg && assigned_reg <= pd_last_xmm_reg, "no xmm register");
+assert(interval->assigned_regHi() == any_reg, "must not have hi register (double xmm values are stored in one register)");
+return LIR_OprFact::double_xmm(assigned_reg - pd_first_xmm_reg);
+}
+#endif
+#ifdef SPARC
+assert(assigned_reg >= pd_first_fpu_reg && assigned_reg <= pd_last_fpu_reg, "no fpu register");
+assert(interval->assigned_regHi() >= pd_first_fpu_reg && interval->assigned_regHi() <= pd_last_fpu_reg, "no fpu register");
+assert(assigned_reg % 2 == 0 && assigned_reg + 1 == interval->assigned_regHi(), "must be sequential and even");
+LIR_Opr result = LIR_OprFact::double_fpu(interval->assigned_regHi() - pd_first_fpu_reg, assigned_reg - pd_first_fpu_reg);
+#else
+assert(assigned_reg >= pd_first_fpu_reg && assigned_reg <= pd_last_fpu_reg, "no fpu register");
+assert(interval->assigned_regHi() == any_reg, "must not have hi register (double fpu values are stored in one register on Intel)");
+LIR_Opr result = LIR_OprFact::double_fpu(assigned_reg - pd_first_fpu_reg);
+#endif
+return result;
+}
+default: {
+ShouldNotReachHere();
+return LIR_OprFact::illegalOpr;
+}
+}
+}
+}
+LIR_Opr LinearScan::canonical_spill_opr(Interval* interval) {
+assert(interval->canonical_spill_slot() >= nof_regs, "canonical spill slot not set");
+return LIR_OprFact::stack(interval->canonical_spill_slot() - nof_regs, interval->type());
+}
+LIR_Opr LinearScan::color_lir_opr(LIR_Opr opr, int op_id, LIR_OpVisitState::OprMode mode) {
+assert(opr->is_virtual(), "should not call this otherwise");
+Interval* interval = interval_at(opr->vreg_number());
+assert(interval != NULL, "interval must exist");
+if (op_id != -1) {
+#ifdef ASSERT
+BlockBegin* block = block_of_op_with_id(op_id);
+if (block->number_of_sux() <= 1 && op_id == block->last_lir_instruction_id()) {
+// check if spill moves could have been appended at the end of this block, but
+// before the branch instruction. So the split child information for this branch would
+// be incorrect.
+LIR_OpBranch* branch = block->lir()->instructions_list()->last()->as_OpBranch();
+if (branch != NULL) {
+if (block->live_out().at(opr->vreg_number())) {
+assert(branch->cond() == lir_cond_always, "block does not end with an unconditional jump");
+assert(false, "can't get split child for the last branch of a block because the information would be incorrect (moves are inserted before the branch in resolve_data_flow)");
+}
+}
+}
+#endif
+// operands are not changed when an interval is split during allocation,
+// so search the right interval here
+interval = split_child_at_op_id(interval, op_id, mode);
+}
+LIR_Opr res = operand_for_interval(interval);
+#ifdef IA32
+// new semantic for is_last_use: not only set on definite end of interval,
+// but also before hole
+// This may still miss some cases (e.g. for dead values), but it is not necessary that the
+// last use information is completely correct
+// information is only needed for fpu stack allocation
+if (res->is_fpu_register()) {
+if (opr->is_last_use() || op_id == interval->to() || (op_id != -1 && interval->has_hole_between(op_id, op_id + 1))) {
+assert(op_id == -1 || !is_block_begin(op_id), "holes at begin of block may also result from control flow");
+res = res->make_last_use();
+}
+}
+#endif
+assert(!gen()->is_vreg_flag_set(opr->vreg_number(), LIRGenerator::callee_saved) || !FrameMap::is_caller_save_register(res), "bad allocation");
+return res;
+}
+#ifdef ASSERT
+// some methods used to check correctness of debug information
+void assert_no_register_values(GrowableArray<ScopeValue*>* values) {
+if (values == NULL) {
+return;
+}
+for (int i = 0; i < values->length(); i++) {
+ScopeValue* value = values->at(i);
+if (value->is_location()) {
+Location location = ((LocationValue*)value)->location();
+assert(location.where() == Location::on_stack, "value is in register");
+}
+}
+}
+void assert_no_register_values(GrowableArray<MonitorValue*>* values) {
+if (values == NULL) {
+return;
+}
+for (int i = 0; i < values->length(); i++) {
+MonitorValue* value = values->at(i);
+if (value->owner()->is_location()) {
+Location location = ((LocationValue*)value->owner())->location();
+assert(location.where() == Location::on_stack, "owner is in register");
+}
+assert(value->basic_lock().where() == Location::on_stack, "basic_lock is in register");
+}
+}
+void assert_equal(Location l1, Location l2) {
+assert(l1.where() == l2.where() && l1.type() == l2.type() && l1.offset() == l2.offset(), "");
+}
+void assert_equal(ScopeValue* v1, ScopeValue* v2) {
+if (v1->is_location()) {
+assert(v2->is_location(), "");
+assert_equal(((LocationValue*)v1)->location(), ((LocationValue*)v2)->location());
+} else if (v1->is_constant_int()) {
+assert(v2->is_constant_int(), "");
+assert(((ConstantIntValue*)v1)->value() == ((ConstantIntValue*)v2)->value(), "");
+} else if (v1->is_constant_double()) {
+assert(v2->is_constant_double(), "");
+assert(((ConstantDoubleValue*)v1)->value() == ((ConstantDoubleValue*)v2)->value(), "");
+} else if (v1->is_constant_long()) {
+assert(v2->is_constant_long(), "");
+assert(((ConstantLongValue*)v1)->value() == ((ConstantLongValue*)v2)->value(), "");
+} else if (v1->is_constant_oop()) {
+assert(v2->is_constant_oop(), "");
+assert(((ConstantOopWriteValue*)v1)->value() == ((ConstantOopWriteValue*)v2)->value(), "");
+} else {
+ShouldNotReachHere();
+}
+}
+void assert_equal(MonitorValue* m1, MonitorValue* m2) {
+assert_equal(m1->owner(), m2->owner());
+assert_equal(m1->basic_lock(), m2->basic_lock());
+}
+void assert_equal(IRScopeDebugInfo* d1, IRScopeDebugInfo* d2) {
+assert(d1->scope() == d2->scope(), "not equal");
+assert(d1->bci() == d2->bci(), "not equal");
+if (d1->locals() != NULL) {
+assert(d1->locals() != NULL && d2->locals() != NULL, "not equal");
+assert(d1->locals()->length() == d2->locals()->length(), "not equal");
+for (int i = 0; i < d1->locals()->length(); i++) {
+assert_equal(d1->locals()->at(i), d2->locals()->at(i));
+}
+} else {
+assert(d1->locals() == NULL && d2->locals() == NULL, "not equal");
+}
+if (d1->expressions() != NULL) {
+assert(d1->expressions() != NULL && d2->expressions() != NULL, "not equal");
+assert(d1->expressions()->length() == d2->expressions()->length(), "not equal");
+for (int i = 0; i < d1->expressions()->length(); i++) {
+assert_equal(d1->expressions()->at(i), d2->expressions()->at(i));
+}
+} else {
+assert(d1->expressions() == NULL && d2->expressions() == NULL, "not equal");
+}
+if (d1->monitors() != NULL) {
+assert(d1->monitors() != NULL && d2->monitors() != NULL, "not equal");
+assert(d1->monitors()->length() == d2->monitors()->length(), "not equal");
+for (int i = 0; i < d1->monitors()->length(); i++) {
+assert_equal(d1->monitors()->at(i), d2->monitors()->at(i));
+}
+} else {
+assert(d1->monitors() == NULL && d2->monitors() == NULL, "not equal");
+}
+if (d1->caller() != NULL) {
+assert(d1->caller() != NULL && d2->caller() != NULL, "not equal");
+assert_equal(d1->caller(), d2->caller());
+} else {
+assert(d1->caller() == NULL && d2->caller() == NULL, "not equal");
+}
+}
+void check_stack_depth(CodeEmitInfo* info, int stack_end) {
+if (info->bci() != SynchronizationEntryBCI && !info->scope()->method()->is_native()) {
+Bytecodes::Code code = info->scope()->method()->java_code_at_bci(info->bci());
+switch (code) {
+case Bytecodes::_ifnull    : // fall through
+case Bytecodes::_ifnonnull : // fall through
+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 :
+assert(stack_end >= -Bytecodes::depth(code), "must have non-empty expression stack at if bytecode");
+break;
+}
+}
+}
+#endif // ASSERT
+IntervalWalker* LinearScan::init_compute_oop_maps() {
+// setup lists of potential oops for walking
+Interval* oop_intervals;
+Interval* non_oop_intervals;
+create_unhandled_lists(&oop_intervals, &non_oop_intervals, is_oop_interval, NULL);
+// intervals that have no oops inside need not to be processed
+// to ensure a walking until the last instruction id, add a dummy interval
+// with a high operation id
+non_oop_intervals = new Interval(any_reg);
+non_oop_intervals->add_range(max_jint - 2, max_jint - 1);
+return new IntervalWalker(this, oop_intervals, non_oop_intervals);
+}
+OopMap* LinearScan::compute_oop_map(IntervalWalker* iw, LIR_Op* op, CodeEmitInfo* info, bool is_call_site) {
+TRACE_LINEAR_SCAN(3, tty->print_cr("creating oop map at op_id %d", op->id()));
+// walk before the current operation -> intervals that start at
+// the operation (= output operands of the operation) are not
+// included in the oop map
+iw->walk_before(op->id());
+int frame_size = frame_map()->framesize();
+int arg_count = frame_map()->oop_map_arg_count();
+OopMap* map = new OopMap(frame_size, arg_count);
+// Check if this is a patch site.
+bool is_patch_info = false;
+if (op->code() == lir_move) {
+assert(!is_call_site, "move must not be a call site");
+assert(op->as_Op1() != NULL, "move must be LIR_Op1");
+LIR_Op1* move = (LIR_Op1*)op;
+is_patch_info = move->patch_code() != lir_patch_none;
+}
+// Iterate through active intervals
+for (Interval* interval = iw->active_first(fixedKind); interval != Interval::end(); interval = interval->next()) {
+int assigned_reg = interval->assigned_reg();
+assert(interval->current_from() <= op->id() && op->id() <= interval->current_to(), "interval should not be active otherwise");
+assert(interval->assigned_regHi() == any_reg, "oop must be single word");
+assert(interval->reg_num() >= LIR_OprDesc::vreg_base, "fixed interval found");
+// Check if this range covers the instruction. Intervals that
+// start or end at the current operation are not included in the
+// oop map, except in the case of patching moves.  For patching
+// moves, any intervals which end at this instruction are included
+// in the oop map since we may safepoint while doing the patch
+// before we've consumed the inputs.
+if (is_patch_info || op->id() < interval->current_to()) {
+// caller-save registers must not be included into oop-maps at calls
+assert(!is_call_site || assigned_reg >= nof_regs || !is_caller_save(assigned_reg), "interval is in a caller-save register at a call -> register will be overwritten");
+VMReg name = vm_reg_for_interval(interval);
+map->set_oop(name);
+// Spill optimization: when the stack value is guaranteed to be always correct,
+// then it must be added to the oop map even if the interval is currently in a register
+if (interval->always_in_memory() &&
+op->id() > interval->spill_definition_pos() &&
+interval->assigned_reg() != interval->canonical_spill_slot()) {
+assert(interval->spill_definition_pos() > 0, "position not set correctly");
+assert(interval->canonical_spill_slot() >= LinearScan::nof_regs, "no spill slot assigned");
+assert(interval->assigned_reg() < LinearScan::nof_regs, "interval is on stack, so stack slot is registered twice");
+map->set_oop(frame_map()->slot_regname(interval->canonical_spill_slot() - LinearScan::nof_regs));
+}
+}
+}
+// add oops from lock stack
+assert(info->stack() != NULL, "CodeEmitInfo must always have a stack");
+int locks_count = info->stack()->locks_size();
+for (int i = 0; i < locks_count; i++) {
+map->set_oop(frame_map()->monitor_object_regname(i));
+}
+return map;
+}
+void LinearScan::compute_oop_map(IntervalWalker* iw, const LIR_OpVisitState &visitor, LIR_Op* op) {
+assert(visitor.info_count() > 0, "no oop map needed");
+// compute oop_map only for first CodeEmitInfo
+// because it is (in most cases) equal for all other infos of the same operation
+CodeEmitInfo* first_info = visitor.info_at(0);
+OopMap* first_oop_map = compute_oop_map(iw, op, first_info, visitor.has_call());
+for (int i = 0; i < visitor.info_count(); i++) {
+CodeEmitInfo* info = visitor.info_at(i);
+OopMap* oop_map = first_oop_map;
+if (info->stack()->locks_size() != first_info->stack()->locks_size()) {
+// this info has a different number of locks then the precomputed oop map
+// (possible for lock and unlock instructions) -> compute oop map with
+// correct lock information
+oop_map = compute_oop_map(iw, op, info, visitor.has_call());
+}
+if (info->_oop_map == NULL) {
+info->_oop_map = oop_map;
+} else {
+// a CodeEmitInfo can not be shared between different LIR-instructions
+// because interval splitting can occur anywhere between two instructions
+// and so the oop maps must be different
+// -> check if the already set oop_map is exactly the one calculated for this operation
+assert(info->_oop_map == oop_map, "same CodeEmitInfo used for multiple LIR instructions");
+}
+}
+}
+// frequently used constants
+ConstantOopWriteValue LinearScan::_oop_null_scope_value = ConstantOopWriteValue(NULL);
+ConstantIntValue      LinearScan::_int_m1_scope_value = ConstantIntValue(-1);
+ConstantIntValue      LinearScan::_int_0_scope_value =  ConstantIntValue(0);
+ConstantIntValue      LinearScan::_int_1_scope_value =  ConstantIntValue(1);
+ConstantIntValue      LinearScan::_int_2_scope_value =  ConstantIntValue(2);
+LocationValue         _illegal_value = LocationValue(Location());
+void LinearScan::init_compute_debug_info() {
+// cache for frequently used scope values
+// (cpu registers and stack slots)
+_scope_value_cache = ScopeValueArray((LinearScan::nof_cpu_regs + frame_map()->argcount() + max_spills()) * 2, NULL);
+}
+MonitorValue* LinearScan::location_for_monitor_index(int monitor_index) {
+Location loc;
+if (!frame_map()->location_for_monitor_object(monitor_index, &loc)) {
+bailout("too large frame");
+}
+ScopeValue* object_scope_value = new LocationValue(loc);
+if (!frame_map()->location_for_monitor_lock(monitor_index, &loc)) {
+bailout("too large frame");
+}
+return new MonitorValue(object_scope_value, loc);
+}
+LocationValue* LinearScan::location_for_name(int name, Location::Type loc_type) {
+Location loc;
+if (!frame_map()->locations_for_slot(name, loc_type, &loc)) {
+bailout("too large frame");
+}
+return new LocationValue(loc);
+}
+int LinearScan::append_scope_value_for_constant(LIR_Opr opr, GrowableArray<ScopeValue*>* scope_values) {
+assert(opr->is_constant(), "should not be called otherwise");
+LIR_Const* c = opr->as_constant_ptr();
+BasicType t = c->type();
+switch (t) {
+case T_OBJECT: {
+jobject value = c->as_jobject();
+if (value == NULL) {
+scope_values->append(&_oop_null_scope_value);
+} else {
+scope_values->append(new ConstantOopWriteValue(c->as_jobject()));
+}
+return 1;
+}
+case T_INT: // fall through
+case T_FLOAT: {
+int value = c->as_jint_bits();
+switch (value) {
+case -1: scope_values->append(&_int_m1_scope_value); break;
+case 0:  scope_values->append(&_int_0_scope_value); break;
+case 1:  scope_values->append(&_int_1_scope_value); break;
+case 2:  scope_values->append(&_int_2_scope_value); break;
+default: scope_values->append(new ConstantIntValue(c->as_jint_bits())); break;
+}
+return 1;
+}
+case T_LONG: // fall through
+case T_DOUBLE: {
+if (hi_word_offset_in_bytes > lo_word_offset_in_bytes) {
+scope_values->append(new ConstantIntValue(c->as_jint_hi_bits()));
+scope_values->append(new ConstantIntValue(c->as_jint_lo_bits()));
+} else {
+scope_values->append(new ConstantIntValue(c->as_jint_lo_bits()));
+scope_values->append(new ConstantIntValue(c->as_jint_hi_bits()));
+}
+return 2;
+}
+default:
+ShouldNotReachHere();
+}
+}
+int LinearScan::append_scope_value_for_operand(LIR_Opr opr, GrowableArray<ScopeValue*>* scope_values) {
+if (opr->is_single_stack()) {
+int stack_idx = opr->single_stack_ix();
+bool is_oop = opr->is_oop_register();
+int cache_idx = (stack_idx + LinearScan::nof_cpu_regs) * 2 + (is_oop ? 1 : 0);
+ScopeValue* sv = _scope_value_cache.at(cache_idx);
+if (sv == NULL) {
+Location::Type loc_type = is_oop ? Location::oop : Location::normal;
+sv = location_for_name(stack_idx, loc_type);
+_scope_value_cache.at_put(cache_idx, sv);
+}
+// check if cached value is correct
+DEBUG_ONLY(assert_equal(sv, location_for_name(stack_idx, is_oop ? Location::oop : Location::normal)));
+scope_values->append(sv);
+return 1;
+} else if (opr->is_single_cpu()) {
+bool is_oop = opr->is_oop_register();
+int cache_idx = opr->cpu_regnr() * 2 + (is_oop ? 1 : 0);
+ScopeValue* sv = _scope_value_cache.at(cache_idx);
+if (sv == NULL) {
+Location::Type loc_type = is_oop ? Location::oop : Location::normal;
+VMReg rname = frame_map()->regname(opr);
+sv = new LocationValue(Location::new_reg_loc(loc_type, rname));
+_scope_value_cache.at_put(cache_idx, sv);
+}
+// check if cached value is correct
+DEBUG_ONLY(assert_equal(sv, new LocationValue(Location::new_reg_loc(is_oop ? Location::oop : Location::normal, frame_map()->regname(opr)))));
+scope_values->append(sv);
+return 1;
+#ifdef IA32
+} else if (opr->is_single_xmm()) {
+VMReg rname = opr->as_xmm_float_reg()->as_VMReg();
+LocationValue* sv = new LocationValue(Location::new_reg_loc(Location::normal, rname));
+scope_values->append(sv);
+return 1;
+#endif
+} else if (opr->is_single_fpu()) {
+#ifdef IA32
+// the exact location of fpu stack values is only known
+// during fpu stack allocation, so the stack allocator object
+// must be present
+assert(use_fpu_stack_allocation(), "should not have float stack values without fpu stack allocation (all floats must be SSE2)");
+assert(_fpu_stack_allocator != NULL, "must be present");
+opr = _fpu_stack_allocator->to_fpu_stack(opr);
+#endif
+Location::Type loc_type = float_saved_as_double ? Location::float_in_dbl : Location::normal;
+VMReg rname = frame_map()->fpu_regname(opr->fpu_regnr());
+LocationValue* sv = new LocationValue(Location::new_reg_loc(loc_type, rname));
+scope_values->append(sv);
+return 1;
+} else {
+// double-size operands
+ScopeValue* first;
+ScopeValue* second;
+if (opr->is_double_stack()) {
+Location loc1, loc2;
+if (!frame_map()->locations_for_slot(opr->double_stack_ix(), Location::normal, &loc1, &loc2)) {
+bailout("too large frame");
+}
+first =  new LocationValue(loc1);
+second = new LocationValue(loc2);
+} else if (opr->is_double_cpu()) {
+#ifdef _LP64
+VMReg rname_first = opr->as_register_lo()->as_VMReg();
+first = new LocationValue(Location::new_reg_loc(Location::lng, rname_first));
+second = &_int_0_scope_value;
+#else
+VMReg rname_first = opr->as_register_lo()->as_VMReg();
+VMReg rname_second = opr->as_register_hi()->as_VMReg();
+if (hi_word_offset_in_bytes < lo_word_offset_in_bytes) {
+// lo/hi and swapped relative to first and second, so swap them
+VMReg tmp = rname_first;
+rname_first = rname_second;
+rname_second = tmp;
+}
+first = new LocationValue(Location::new_reg_loc(Location::normal, rname_first));
+second = new LocationValue(Location::new_reg_loc(Location::normal, rname_second));
+#endif
+#ifdef IA32
+} else if (opr->is_double_xmm()) {
+assert(opr->fpu_regnrLo() == opr->fpu_regnrHi(), "assumed in calculation");
+VMReg rname_first  = opr->as_xmm_double_reg()->as_VMReg();
+first = new LocationValue(Location::new_reg_loc(Location::normal, rname_first));
+// %%% This is probably a waste but we'll keep things as they were for now
+if (true) {
+VMReg rname_second = rname_first->next();
+second = new LocationValue(Location::new_reg_loc(Location::normal, rname_second));
+}
+#endif
+} else if (opr->is_double_fpu()) {
+// On SPARC, fpu_regnrLo/fpu_regnrHi represents the two halves of
+// the double as float registers in the native ordering. On IA32,
+// fpu_regnrLo is a FPU stack slot whose VMReg represents
+// the low-order word of the double and fpu_regnrLo + 1 is the
+// name for the other half.  *first and *second must represent the
+// least and most significant words, respectively.
+#ifdef IA32
+// the exact location of fpu stack values is only known
+// during fpu stack allocation, so the stack allocator object
+// must be present
+assert(use_fpu_stack_allocation(), "should not have float stack values without fpu stack allocation (all floats must be SSE2)");
+assert(_fpu_stack_allocator != NULL, "must be present");
+opr = _fpu_stack_allocator->to_fpu_stack(opr);
+assert(opr->fpu_regnrLo() == opr->fpu_regnrHi(), "assumed in calculation (only fpu_regnrHi is used)");
+#endif
+#ifdef SPARC
+assert(opr->fpu_regnrLo() == opr->fpu_regnrHi() + 1, "assumed in calculation (only fpu_regnrHi is used)");
+#endif
+VMReg rname_first = frame_map()->fpu_regname(opr->fpu_regnrHi());
+first = new LocationValue(Location::new_reg_loc(Location::normal, rname_first));
+// %%% This is probably a waste but we'll keep things as they were for now
+if (true) {
+VMReg rname_second = rname_first->next();
+second = new LocationValue(Location::new_reg_loc(Location::normal, rname_second));
+}
+} else {
+ShouldNotReachHere();
+first = NULL;
+second = NULL;
+}
+assert(first != NULL && second != NULL, "must be set");
+// The convention the interpreter uses is that the second local
+// holds the first raw word of the native double representation.
+// This is actually reasonable, since locals and stack arrays
+// grow downwards in all implementations.
+// (If, on some machine, the interpreter's Java locals or stack
+// were to grow upwards, the embedded doubles would be word-swapped.)
+scope_values->append(second);
+scope_values->append(first);
+return 2;
+}
+}
+int LinearScan::append_scope_value(int op_id, Value value, GrowableArray<ScopeValue*>* scope_values) {
+if (value != NULL) {
+LIR_Opr opr = value->operand();
+Constant* con = value->as_Constant();
+assert(con == NULL || opr->is_virtual() || opr->is_constant() || opr->is_illegal(), "asumption: Constant instructions have only constant operands (or illegal if constant is optimized away)");
+assert(con != NULL || opr->is_virtual(), "asumption: non-Constant instructions have only virtual operands");
+if (con != NULL && !con->is_pinned() && !opr->is_constant()) {
+// Unpinned constants may have a virtual operand for a part of the lifetime
+// or may be illegal when it was optimized away,
+// so always use a constant operand
+opr = LIR_OprFact::value_type(con->type());
+}
+assert(opr->is_virtual() || opr->is_constant(), "other cases not allowed here");
+if (opr->is_virtual()) {
+LIR_OpVisitState::OprMode mode = LIR_OpVisitState::inputMode;
+BlockBegin* block = block_of_op_with_id(op_id);
+if (block->number_of_sux() == 1 && op_id == block->last_lir_instruction_id()) {
+// generating debug information for the last instruction of a block.
+// if this instruction is a branch, spill moves are inserted before this branch
+// and so the wrong operand would be returned (spill moves at block boundaries are not
+// considered in the live ranges of intervals)
+// Solution: use the first op_id of the branch target block instead.
+if (block->lir()->instructions_list()->last()->as_OpBranch() != NULL) {
+if (block->live_out().at(opr->vreg_number())) {
+op_id = block->sux_at(0)->first_lir_instruction_id();
+mode = LIR_OpVisitState::outputMode;
+}
+}
+}
+// Get current location of operand
+// The operand must be live because debug information is considered when building the intervals
+// if the interval is not live, color_lir_opr will cause an assertion failure
+opr = color_lir_opr(opr, op_id, mode);
+assert(!has_call(op_id) || opr->is_stack() || !is_caller_save(reg_num(opr)), "can not have caller-save register operands at calls");
+// Append to ScopeValue array
+return append_scope_value_for_operand(opr, scope_values);
+} else {
+assert(value->as_Constant() != NULL, "all other instructions have only virtual operands");
+assert(opr->is_constant(), "operand must be constant");
+return append_scope_value_for_constant(opr, scope_values);
+}
+} else {
+// append a dummy value because real value not needed
+scope_values->append(&_illegal_value);
+return 1;
+}
+}
+IRScopeDebugInfo* LinearScan::compute_debug_info_for_scope(int op_id, IRScope* cur_scope, ValueStack* cur_state, ValueStack* innermost_state, int cur_bci, int stack_end, int locks_end) {
+IRScopeDebugInfo* caller_debug_info = NULL;
+int stack_begin, locks_begin;
+ValueStack* caller_state = cur_scope->caller_state();
+if (caller_state != NULL) {
+// process recursively to compute outermost scope first
+stack_begin = caller_state->stack_size();
+locks_begin = caller_state->locks_size();
+caller_debug_info = compute_debug_info_for_scope(op_id, cur_scope->caller(), caller_state, innermost_state, cur_scope->caller_bci(), stack_begin, locks_begin);
+} else {
+stack_begin = 0;
+locks_begin = 0;
+}
+// initialize these to null.
+// If we don't need deopt info or there are no locals, expressions or monitors,
+// then these get recorded as no information and avoids the allocation of 0 length arrays.
+GrowableArray<ScopeValue*>*   locals      = NULL;
+GrowableArray<ScopeValue*>*   expressions = NULL;
+GrowableArray<MonitorValue*>* monitors    = NULL;
+// describe local variable values
+int nof_locals = cur_scope->method()->max_locals();
+if (nof_locals > 0) {
+locals = new GrowableArray<ScopeValue*>(nof_locals);
+int pos = 0;
+while (pos < nof_locals) {
+assert(pos < cur_state->locals_size(), "why not?");
+Value local = cur_state->local_at(pos);
+pos += append_scope_value(op_id, local, locals);
+assert(locals->length() == pos, "must match");
+}
+assert(locals->length() == cur_scope->method()->max_locals(), "wrong number of locals");
+assert(locals->length() == cur_state->locals_size(), "wrong number of locals");
+}
+// describe expression stack
+//
+// When we inline methods containing exception handlers, the
+// "lock_stacks" are changed to preserve expression stack values
+// in caller scopes when exception handlers are present. This
+// can cause callee stacks to be smaller than caller stacks.
+if (stack_end > innermost_state->stack_size()) {
+stack_end = innermost_state->stack_size();
+}
+int nof_stack = stack_end - stack_begin;
+if (nof_stack > 0) {
+expressions = new GrowableArray<ScopeValue*>(nof_stack);
+int pos = stack_begin;
+while (pos < stack_end) {
+Value expression = innermost_state->stack_at_inc(pos);
+append_scope_value(op_id, expression, expressions);
+assert(expressions->length() + stack_begin == pos, "must match");
+}
+}
+// describe monitors
+assert(locks_begin <= locks_end, "error in scope iteration");
+int nof_locks = locks_end - locks_begin;
+if (nof_locks > 0) {
+monitors = new GrowableArray<MonitorValue*>(nof_locks);
+for (int i = locks_begin; i < locks_end; i++) {
+monitors->append(location_for_monitor_index(i));
+}
+}
+return new IRScopeDebugInfo(cur_scope, cur_bci, locals, expressions, monitors, caller_debug_info);
+}
+void LinearScan::compute_debug_info(CodeEmitInfo* info, int op_id) {
+if (!compilation()->needs_debug_information()) {
+return;
+}
+TRACE_LINEAR_SCAN(3, tty->print_cr("creating debug information at op_id %d", op_id));
+IRScope* innermost_scope = info->scope();
+ValueStack* innermost_state = info->stack();
+assert(innermost_scope != NULL && innermost_state != NULL, "why is it missing?");
+int stack_end = innermost_state->stack_size();
+int locks_end = innermost_state->locks_size();
+DEBUG_ONLY(check_stack_depth(info, stack_end));
+if (info->_scope_debug_info == NULL) {
+// compute debug information
+info->_scope_debug_info = compute_debug_info_for_scope(op_id, innermost_scope, innermost_state, innermost_state, info->bci(), stack_end, locks_end);
+} else {
+// debug information already set. Check that it is correct from the current point of view
+DEBUG_ONLY(assert_equal(info->_scope_debug_info, compute_debug_info_for_scope(op_id, innermost_scope, innermost_state, innermost_state, info->bci(), stack_end, locks_end)));
+}
+}
+void LinearScan::assign_reg_num(LIR_OpList* instructions, IntervalWalker* iw) {
+LIR_OpVisitState visitor;
+int num_inst = instructions->length();
+bool has_dead = false;
+for (int j = 0; j < num_inst; j++) {
+LIR_Op* op = instructions->at(j);
+if (op == NULL) {  // this can happen when spill-moves are removed in eliminate_spill_moves
+has_dead = true;
+continue;
+}
+int op_id = op->id();
+// visit instruction to get list of operands
+visitor.visit(op);
+// iterate all modes of the visitor and process all virtual operands
+for_each_visitor_mode(mode) {
+int n = visitor.opr_count(mode);
+for (int k = 0; k < n; k++) {
+LIR_Opr opr = visitor.opr_at(mode, k);
+if (opr->is_virtual_register()) {
+visitor.set_opr_at(mode, k, color_lir_opr(opr, op_id, mode));
+}
+}
+}
+if (visitor.info_count() > 0) {
+// exception handling
+if (compilation()->has_exception_handlers()) {
+XHandlers* xhandlers = visitor.all_xhandler();
+int n = xhandlers->length();
+for (int k = 0; k < n; k++) {
+XHandler* handler = xhandlers->handler_at(k);
+if (handler->entry_code() != NULL) {
+assign_reg_num(handler->entry_code()->instructions_list(), NULL);
+}
+}
+} else {
+assert(visitor.all_xhandler()->length() == 0, "missed exception handler");
+}
+// compute oop map
+assert(iw != NULL, "needed for compute_oop_map");
+compute_oop_map(iw, visitor, op);
+// compute debug information
+if (!use_fpu_stack_allocation()) {
+// compute debug information if fpu stack allocation is not needed.
+// when fpu stack allocation is needed, the debug information can not
+// be computed here because the exact location of fpu operands is not known
+// -> debug information is created inside the fpu stack allocator
+int n = visitor.info_count();
+for (int k = 0; k < n; k++) {
+compute_debug_info(visitor.info_at(k), op_id);
+}
+}
+}
+#ifdef ASSERT
+// make sure we haven't made the op invalid.
+op->verify();
+#endif
+#ifndef _LP64
+// remove useless moves
+if (op->code() == lir_move) {
+assert(op->as_Op1() != NULL, "move must be LIR_Op1");
+LIR_Op1* move = (LIR_Op1*)op;
+LIR_Opr src = move->in_opr();
+LIR_Opr dst = move->result_opr();
+if (dst == src ||
+!dst->is_pointer() && !src->is_pointer() &&
+src->is_same_register(dst)) {
+instructions->at_put(j, NULL);
+has_dead = true;
+}
+}
+#endif
+}
+if (has_dead) {
+// iterate all instructions of the block and remove all null-values.
+int insert_point = 0;
+for (int j = 0; j < num_inst; j++) {
+LIR_Op* op = instructions->at(j);
+if (op != NULL) {
+if (insert_point != j) {
+instructions->at_put(insert_point, op);
+}
+insert_point++;
+}
+}
+instructions->truncate(insert_point);
+}
+}
+void LinearScan::assign_reg_num() {
+TIME_LINEAR_SCAN(timer_assign_reg_num);
+init_compute_debug_info();
+IntervalWalker* iw = init_compute_oop_maps();
+int num_blocks = block_count();
+for (int i = 0; i < num_blocks; i++) {
+BlockBegin* block = block_at(i);
+assign_reg_num(block->lir()->instructions_list(), iw);
+}
+}
+void LinearScan::do_linear_scan() {
+NOT_PRODUCT(_total_timer.begin_method());
+number_instructions();
+NOT_PRODUCT(print_lir(1, "Before Register Allocation"));
+compute_local_live_sets();
+compute_global_live_sets();
+CHECK_BAILOUT();
+build_intervals();
+CHECK_BAILOUT();
+sort_intervals_before_allocation();
+NOT_PRODUCT(print_intervals("Before Register Allocation"));
+NOT_PRODUCT(LinearScanStatistic::compute(this, _stat_before_alloc));
+allocate_registers();
+CHECK_BAILOUT();
+resolve_data_flow();
+if (compilation()->has_exception_handlers()) {
+resolve_exception_handlers();
+}
+// fill in number of spill slots into frame_map
+propagate_spill_slots();
+CHECK_BAILOUT();
+NOT_PRODUCT(print_intervals("After Register Allocation"));
+NOT_PRODUCT(print_lir(2, "LIR after register allocation:"));
+DEBUG_ONLY(verify());
+sort_intervals_after_allocation();
+eliminate_spill_moves();
+assign_reg_num();
+CHECK_BAILOUT();
+NOT_PRODUCT(print_lir(2, "LIR after assignment of register numbers:"));
+NOT_PRODUCT(LinearScanStatistic::compute(this, _stat_after_asign));
+{ TIME_LINEAR_SCAN(timer_allocate_fpu_stack);
+if (use_fpu_stack_allocation()) {
+allocate_fpu_stack(); // Only has effect on Intel
+NOT_PRODUCT(print_lir(2, "LIR after FPU stack allocation:"));
+}
+}
+{ TIME_LINEAR_SCAN(timer_optimize_lir);
+EdgeMoveOptimizer::optimize(ir()->code());
+ControlFlowOptimizer::optimize(ir()->code());
+// check that cfg is still correct after optimizations
+ir()->verify();
+}
+NOT_PRODUCT(print_lir(1, "Before Code Generation", false));
+NOT_PRODUCT(LinearScanStatistic::compute(this, _stat_final));
+NOT_PRODUCT(_total_timer.end_method(this));
+}
+// ********** Printing functions
+#ifndef PRODUCT
+void LinearScan::print_timers(double total) {
+_total_timer.print(total);
+}
+void LinearScan::print_statistics() {
+_stat_before_alloc.print("before allocation");
+_stat_after_asign.print("after assignment of register");
+_stat_final.print("after optimization");
+}
+void LinearScan::print_bitmap(BitMap& b) {
+for (unsigned int i = 0; i < b.size(); i++) {
+if (b.at(i)) tty->print("%d ", i);
+}
+tty->cr();
+}
+void LinearScan::print_intervals(const char* label) {
+if (TraceLinearScanLevel >= 1) {
+int i;
+tty->cr();
+tty->print_cr("%s", label);
+for (i = 0; i < interval_count(); i++) {
+Interval* interval = interval_at(i);
+if (interval != NULL) {
+interval->print();
+}
+}
+tty->cr();
+tty->print_cr("--- Basic Blocks ---");
+for (i = 0; i < block_count(); i++) {
+BlockBegin* block = block_at(i);
+tty->print("B%d [%d, %d, %d, %d] ", block->block_id(), block->first_lir_instruction_id(), block->last_lir_instruction_id(), block->loop_index(), block->loop_depth());
+}
+tty->cr();
+tty->cr();
+}
+if (PrintCFGToFile) {
+CFGPrinter::print_intervals(&_intervals, label);
+}
+}
+void LinearScan::print_lir(int level, const char* label, bool hir_valid) {
+if (TraceLinearScanLevel >= level) {
+tty->cr();
+tty->print_cr("%s", label);
+print_LIR(ir()->linear_scan_order());
+tty->cr();
+}
+if (level == 1 && PrintCFGToFile) {
+CFGPrinter::print_cfg(ir()->linear_scan_order(), label, hir_valid, true);
+}
+}
+#endif //PRODUCT
+// ********** verification functions for allocation
+// (check that all intervals have a correct register and that no registers are overwritten)
+#ifdef ASSERT
+void LinearScan::verify() {
+TRACE_LINEAR_SCAN(2, tty->print_cr("********* verifying intervals ******************************************"));
+verify_intervals();
+TRACE_LINEAR_SCAN(2, tty->print_cr("********* verifying that no oops are in fixed intervals ****************"));
+verify_no_oops_in_fixed_intervals();
+TRACE_LINEAR_SCAN(2, tty->print_cr("********* verifying that unpinned constants are not alive across block boundaries"));
+verify_constants();
+TRACE_LINEAR_SCAN(2, tty->print_cr("********* verifying register allocation ********************************"));
+verify_registers();
+TRACE_LINEAR_SCAN(2, tty->print_cr("********* no errors found **********************************************"));
+}
+void LinearScan::verify_intervals() {
+int len = interval_count();
+bool has_error = false;
+for (int i = 0; i < len; i++) {
+Interval* i1 = interval_at(i);
+if (i1 == NULL) continue;
+i1->check_split_children();
+if (i1->reg_num() != i) {
+tty->print_cr("Interval %d is on position %d in list", i1->reg_num(), i); i1->print(); tty->cr();
+has_error = true;
+}
+if (i1->reg_num() >= LIR_OprDesc::vreg_base && i1->type() == T_ILLEGAL) {
+tty->print_cr("Interval %d has no type assigned", i1->reg_num()); i1->print(); tty->cr();
+has_error = true;
+}
+if (i1->assigned_reg() == any_reg) {
+tty->print_cr("Interval %d has no register assigned", i1->reg_num()); i1->print(); tty->cr();
+has_error = true;
+}
+if (i1->assigned_reg() == i1->assigned_regHi()) {
+tty->print_cr("Interval %d: low and high register equal", i1->reg_num()); i1->print(); tty->cr();
+has_error = true;
+}
+if (!is_processed_reg_num(i1->assigned_reg())) {
+tty->print_cr("Can not have an Interval for an ignored register"); i1->print(); tty->cr();
+has_error = true;
+}
+if (i1->first() == Range::end()) {
+tty->print_cr("Interval %d has no Range", i1->reg_num()); i1->print(); tty->cr();
+has_error = true;
+}
+for (Range* r = i1->first(); r != Range::end(); r = r->next()) {
+if (r->from() >= r->to()) {
+tty->print_cr("Interval %d has zero length range", i1->reg_num()); i1->print(); tty->cr();
+has_error = true;
+}
+}
+for (int j = i + 1; j < len; j++) {
+Interval* i2 = interval_at(j);
+if (i2 == NULL) continue;
+// special intervals that are created in MoveResolver
+// -> ignore them because the range information has no meaning there
+if (i1->from() == 1 && i1->to() == 2) continue;
+if (i2->from() == 1 && i2->to() == 2) continue;
+int r1 = i1->assigned_reg();
+int r1Hi = i1->assigned_regHi();
+int r2 = i2->assigned_reg();
+int r2Hi = i2->assigned_regHi();
+if (i1->intersects(i2) && (r1 == r2 || r1 == r2Hi || (r1Hi != any_reg && (r1Hi == r2 || r1Hi == r2Hi)))) {
+tty->print_cr("Intervals %d and %d overlap and have the same register assigned", i1->reg_num(), i2->reg_num());
+i1->print(); tty->cr();
+i2->print(); tty->cr();
+has_error = true;
+}
+}
+}
+assert(has_error == false, "register allocation invalid");
+}
+void LinearScan::verify_no_oops_in_fixed_intervals() {
+LIR_OpVisitState visitor;
+for (int i = 0; i < block_count(); i++) {
+BlockBegin* block = block_at(i);
+LIR_OpList* instructions = block->lir()->instructions_list();
+for (int j = 0; j < instructions->length(); j++) {
+LIR_Op* op = instructions->at(j);
+int op_id = op->id();
+visitor.visit(op);
+// oop-maps at calls do not contain registers, so check is not needed
+if (!visitor.has_call()) {
+for_each_visitor_mode(mode) {
+int n = visitor.opr_count(mode);
+for (int k = 0; k < n; k++) {
+LIR_Opr opr = visitor.opr_at(mode, k);
+if (opr->is_fixed_cpu() && opr->is_oop()) {
+// operand is a non-virtual cpu register and contains an oop
+TRACE_LINEAR_SCAN(4, op->print_on(tty); tty->print("checking operand "); opr->print(); tty->cr());
+Interval* interval = interval_at(reg_num(opr));
+assert(interval != NULL, "no interval");
+if (mode == LIR_OpVisitState::inputMode) {
+if (interval->to() >= op_id + 1) {
+assert(interval->to() < op_id + 2 ||
+interval->has_hole_between(op_id, op_id + 2),
+"oop input operand live after instruction");
+}
+} else if (mode == LIR_OpVisitState::outputMode) {
+if (interval->from() <= op_id - 1) {
+assert(interval->has_hole_between(op_id - 1, op_id),
+"oop input operand live after instruction");
+}
+}
+}
+}
+}
+}
+}
+}
+}
+void LinearScan::verify_constants() {
+int num_regs = num_virtual_regs();
+int size = live_set_size();
+int num_blocks = block_count();
+for (int i = 0; i < num_blocks; i++) {
+BlockBegin* block = block_at(i);
+BitMap live_at_edge = block->live_in();
+// visit all registers where the live_at_edge bit is set
+for (int r = live_at_edge.get_next_one_offset(0, size); r < size; r = live_at_edge.get_next_one_offset(r + 1, size)) {
+TRACE_LINEAR_SCAN(4, tty->print("checking interval %d of block B%d", r, block->block_id()));
+Value value = gen()->instruction_for_vreg(r);
+assert(value != NULL, "all intervals live across block boundaries must have Value");
+assert(value->operand()->is_register() && value->operand()->is_virtual(), "value must have virtual operand");
+assert(value->operand()->vreg_number() == r, "register number must match");
+// TKR assert(value->as_Constant() == NULL || value->is_pinned(), "only pinned constants can be alive accross block boundaries");
+}
+}
+}
+class RegisterVerifier: public StackObj {
+private:
+LinearScan*   _allocator;
+BlockList     _work_list;      // all blocks that must be processed
+IntervalsList _saved_states;   // saved information of previous check
+// simplified access to methods of LinearScan
+Compilation*  compilation() const              { return _allocator->compilation(); }
+Interval*     interval_at(int reg_num) const   { return _allocator->interval_at(reg_num); }
+int           reg_num(LIR_Opr opr) const       { return _allocator->reg_num(opr); }
+// currently, only registers are processed
+int           state_size()                     { return LinearScan::nof_regs; }
+// accessors
+IntervalList* state_for_block(BlockBegin* block) { return _saved_states.at(block->block_id()); }
+void          set_state_for_block(BlockBegin* block, IntervalList* saved_state) { _saved_states.at_put(block->block_id(), saved_state); }
+void          add_to_work_list(BlockBegin* block) { if (!_work_list.contains(block)) _work_list.append(block); }
+// helper functions
+IntervalList* copy(IntervalList* input_state);
+void          state_put(IntervalList* input_state, int reg, Interval* interval);
+bool          check_state(IntervalList* input_state, int reg, Interval* interval);
+void process_block(BlockBegin* block);
+void process_xhandler(XHandler* xhandler, IntervalList* input_state);
+void process_successor(BlockBegin* block, IntervalList* input_state);
+void process_operations(LIR_List* ops, IntervalList* input_state);
+public:
+RegisterVerifier(LinearScan* allocator)
+: _allocator(allocator)
+, _work_list(16)
+, _saved_states(BlockBegin::number_of_blocks(), NULL)
+{ }
+void verify(BlockBegin* start);
+};
+// entry function from LinearScan that starts the verification
+void LinearScan::verify_registers() {
+RegisterVerifier verifier(this);
+verifier.verify(block_at(0));
+}
+void RegisterVerifier::verify(BlockBegin* start) {
+// setup input registers (method arguments) for first block
+IntervalList* input_state = new IntervalList(state_size(), NULL);
+CallingConvention* args = compilation()->frame_map()->incoming_arguments();
+for (int n = 0; n < args->length(); n++) {
+LIR_Opr opr = args->at(n);
+if (opr->is_register()) {
+Interval* interval = interval_at(reg_num(opr));
+if (interval->assigned_reg() < state_size()) {
+input_state->at_put(interval->assigned_reg(), interval);
+}
+if (interval->assigned_regHi() != LinearScan::any_reg && interval->assigned_regHi() < state_size()) {
+input_state->at_put(interval->assigned_regHi(), interval);
+}
+}
+}
+set_state_for_block(start, input_state);
+add_to_work_list(start);
+// main loop for verification
+do {
+BlockBegin* block = _work_list.at(0);
+_work_list.remove_at(0);
+process_block(block);
+} while (!_work_list.is_empty());
+}
+void RegisterVerifier::process_block(BlockBegin* block) {
+TRACE_LINEAR_SCAN(2, tty->cr(); tty->print_cr("process_block B%d", block->block_id()));
+// must copy state because it is modified
+IntervalList* input_state = copy(state_for_block(block));
+if (TraceLinearScanLevel >= 4) {
+tty->print_cr("Input-State of intervals:");
+tty->print("    ");
+for (int i = 0; i < state_size(); i++) {
+if (input_state->at(i) != NULL) {
+tty->print(" %4d", input_state->at(i)->reg_num());
+} else {
+tty->print("   __");
+}
+}
+tty->cr();
+tty->cr();
+}
+// process all operations of the block
+process_operations(block->lir(), input_state);
+// iterate all successors
+for (int i = 0; i < block->number_of_sux(); i++) {
+process_successor(block->sux_at(i), input_state);
+}
+}
+void RegisterVerifier::process_xhandler(XHandler* xhandler, IntervalList* input_state) {
+TRACE_LINEAR_SCAN(2, tty->print_cr("process_xhandler B%d", xhandler->entry_block()->block_id()));
+// must copy state because it is modified
+input_state = copy(input_state);
+if (xhandler->entry_code() != NULL) {
+process_operations(xhandler->entry_code(), input_state);
+}
+process_successor(xhandler->entry_block(), input_state);
+}
+void RegisterVerifier::process_successor(BlockBegin* block, IntervalList* input_state) {
+IntervalList* saved_state = state_for_block(block);
+if (saved_state != NULL) {
+// this block was already processed before.
+// check if new input_state is consistent with saved_state
+bool saved_state_correct = true;
+for (int i = 0; i < state_size(); i++) {
+if (input_state->at(i) != saved_state->at(i)) {
+// current input_state and previous saved_state assume a different
+// interval in this register -> assume that this register is invalid
+if (saved_state->at(i) != NULL) {
+// invalidate old calculation only if it assumed that
+// register was valid. when the register was already invalid,
+// then the old calculation was correct.
+saved_state_correct = false;
+saved_state->at_put(i, NULL);
+TRACE_LINEAR_SCAN(4, tty->print_cr("process_successor B%d: invalidating slot %d", block->block_id(), i));
+}
+}
+}
+if (saved_state_correct) {
+// already processed block with correct input_state
+TRACE_LINEAR_SCAN(2, tty->print_cr("process_successor B%d: previous visit already correct", block->block_id()));
+} else {
+// must re-visit this block
+TRACE_LINEAR_SCAN(2, tty->print_cr("process_successor B%d: must re-visit because input state changed", block->block_id()));
+add_to_work_list(block);
+}
+} else {
+// block was not processed before, so set initial input_state
+TRACE_LINEAR_SCAN(2, tty->print_cr("process_successor B%d: initial visit", block->block_id()));
+set_state_for_block(block, copy(input_state));
+add_to_work_list(block);
+}
+}
+IntervalList* RegisterVerifier::copy(IntervalList* input_state) {
+IntervalList* copy_state = new IntervalList(input_state->length());
+copy_state->push_all(input_state);
+return copy_state;
+}
+void RegisterVerifier::state_put(IntervalList* input_state, int reg, Interval* interval) {
+if (reg != LinearScan::any_reg && reg < state_size()) {
+if (interval != NULL) {
+TRACE_LINEAR_SCAN(4, tty->print_cr("        reg[%d] = %d", reg, interval->reg_num()));
+} else if (input_state->at(reg) != NULL) {
+TRACE_LINEAR_SCAN(4, tty->print_cr("        reg[%d] = NULL", reg));
+}
+input_state->at_put(reg, interval);
+}
+}
+bool RegisterVerifier::check_state(IntervalList* input_state, int reg, Interval* interval) {
+if (reg != LinearScan::any_reg && reg < state_size()) {
+if (input_state->at(reg) != interval) {
+tty->print_cr("!! Error in register allocation: register %d does not contain interval %d", reg, interval->reg_num());
+return true;
+}
+}
+return false;
+}
+void RegisterVerifier::process_operations(LIR_List* ops, IntervalList* input_state) {
+// visit all instructions of the block
+LIR_OpVisitState visitor;
+bool has_error = false;
+for (int i = 0; i < ops->length(); i++) {
+LIR_Op* op = ops->at(i);
+visitor.visit(op);
+TRACE_LINEAR_SCAN(4, op->print_on(tty));
+// check if input operands are correct
+int j;
+int n = visitor.opr_count(LIR_OpVisitState::inputMode);
+for (j = 0; j < n; j++) {
+LIR_Opr opr = visitor.opr_at(LIR_OpVisitState::inputMode, j);
+if (opr->is_register() && LinearScan::is_processed_reg_num(reg_num(opr))) {
+Interval* interval = interval_at(reg_num(opr));
+if (op->id() != -1) {
+interval = interval->split_child_at_op_id(op->id(), LIR_OpVisitState::inputMode);
+}
+has_error |= check_state(input_state, interval->assigned_reg(),   interval->split_parent());
+has_error |= check_state(input_state, interval->assigned_regHi(), interval->split_parent());
+// When an operand is marked with is_last_use, then the fpu stack allocator
+// removes the register from the fpu stack -> the register contains no value
+if (opr->is_last_use()) {
+state_put(input_state, interval->assigned_reg(),   NULL);
+state_put(input_state, interval->assigned_regHi(), NULL);
+}
+}
+}
+// invalidate all caller save registers at calls
+if (visitor.has_call()) {
+for (j = 0; j < FrameMap::nof_caller_save_cpu_regs; j++) {
+state_put(input_state, reg_num(FrameMap::caller_save_cpu_reg_at(j)), NULL);
+}
+for (j = 0; j < FrameMap::nof_caller_save_fpu_regs; j++) {
+state_put(input_state, reg_num(FrameMap::caller_save_fpu_reg_at(j)), NULL);
+}
+#ifdef IA32
+for (j = 0; j < FrameMap::nof_caller_save_xmm_regs; j++) {
+state_put(input_state, reg_num(FrameMap::caller_save_xmm_reg_at(j)), NULL);
+}
+#endif
+}
+// process xhandler before output and temp operands
+XHandlers* xhandlers = visitor.all_xhandler();
+n = xhandlers->length();
+for (int k = 0; k < n; k++) {
+process_xhandler(xhandlers->handler_at(k), input_state);
+}
+// set temp operands (some operations use temp operands also as output operands, so can't set them NULL)
+n = visitor.opr_count(LIR_OpVisitState::tempMode);
+for (j = 0; j < n; j++) {
+LIR_Opr opr = visitor.opr_at(LIR_OpVisitState::tempMode, j);
+if (opr->is_register() && LinearScan::is_processed_reg_num(reg_num(opr))) {
+Interval* interval = interval_at(reg_num(opr));
+if (op->id() != -1) {
+interval = interval->split_child_at_op_id(op->id(), LIR_OpVisitState::tempMode);
+}
+state_put(input_state, interval->assigned_reg(),   interval->split_parent());
+state_put(input_state, interval->assigned_regHi(), interval->split_parent());
+}
+}
+// set output operands
+n = visitor.opr_count(LIR_OpVisitState::outputMode);
+for (j = 0; j < n; j++) {
+LIR_Opr opr = visitor.opr_at(LIR_OpVisitState::outputMode, j);
+if (opr->is_register() && LinearScan::is_processed_reg_num(reg_num(opr))) {
+Interval* interval = interval_at(reg_num(opr));
+if (op->id() != -1) {
+interval = interval->split_child_at_op_id(op->id(), LIR_OpVisitState::outputMode);
+}
+state_put(input_state, interval->assigned_reg(),   interval->split_parent());
+state_put(input_state, interval->assigned_regHi(), interval->split_parent());
+}
+}
+}
+assert(has_error == false, "Error in register allocation");
+}
+#endif // ASSERT
+// **** Implementation of MoveResolver ******************************
+MoveResolver::MoveResolver(LinearScan* allocator) :
+_allocator(allocator),
+_multiple_reads_allowed(false),
+_mapping_from(8),
+_mapping_from_opr(8),
+_mapping_to(8),
+_insert_list(NULL),
+_insert_idx(-1),
+_insertion_buffer()
+{
+for (int i = 0; i < LinearScan::nof_regs; i++) {
+_register_blocked[i] = 0;
+}
+DEBUG_ONLY(check_empty());
+}
+#ifdef ASSERT
+void MoveResolver::check_empty() {
+assert(_mapping_from.length() == 0 && _mapping_from_opr.length() == 0 && _mapping_to.length() == 0, "list must be empty before and after processing");
+for (int i = 0; i < LinearScan::nof_regs; i++) {
+assert(register_blocked(i) == 0, "register map must be empty before and after processing");
+}
+assert(_multiple_reads_allowed == false, "must have default value");
+}
+void MoveResolver::verify_before_resolve() {
+assert(_mapping_from.length() == _mapping_from_opr.length(), "length must be equal");
+assert(_mapping_from.length() == _mapping_to.length(), "length must be equal");
+assert(_insert_list != NULL && _insert_idx != -1, "insert position not set");
+int i, j;
+if (!_multiple_reads_allowed) {
+for (i = 0; i < _mapping_from.length(); i++) {
+for (j = i + 1; j < _mapping_from.length(); j++) {
+assert(_mapping_from.at(i) == NULL || _mapping_from.at(i) != _mapping_from.at(j), "cannot read from same interval twice");
+}
+}
+}
+for (i = 0; i < _mapping_to.length(); i++) {
+for (j = i + 1; j < _mapping_to.length(); j++) {
+assert(_mapping_to.at(i) != _mapping_to.at(j), "cannot write to same interval twice");
+}
+}
+BitMap used_regs(LinearScan::nof_regs + allocator()->frame_map()->argcount() + allocator()->max_spills());
+used_regs.clear();
+if (!_multiple_reads_allowed) {
+for (i = 0; i < _mapping_from.length(); i++) {
+Interval* it = _mapping_from.at(i);
+if (it != NULL) {
+assert(!used_regs.at(it->assigned_reg()), "cannot read from same register twice");
+used_regs.set_bit(it->assigned_reg());
+if (it->assigned_regHi() != LinearScan::any_reg) {
+assert(!used_regs.at(it->assigned_regHi()), "cannot read from same register twice");
+used_regs.set_bit(it->assigned_regHi());
+}
+}
+}
+}
+used_regs.clear();
+for (i = 0; i < _mapping_to.length(); i++) {
+Interval* it = _mapping_to.at(i);
+assert(!used_regs.at(it->assigned_reg()), "cannot write to same register twice");
+used_regs.set_bit(it->assigned_reg());
+if (it->assigned_regHi() != LinearScan::any_reg) {
+assert(!used_regs.at(it->assigned_regHi()), "cannot write to same register twice");
+used_regs.set_bit(it->assigned_regHi());
+}
+}
+used_regs.clear();
+for (i = 0; i < _mapping_from.length(); i++) {
+Interval* it = _mapping_from.at(i);
+if (it != NULL && it->assigned_reg() >= LinearScan::nof_regs) {
+used_regs.set_bit(it->assigned_reg());
+}
+}
+for (i = 0; i < _mapping_to.length(); i++) {
+Interval* it = _mapping_to.at(i);
+assert(!used_regs.at(it->assigned_reg()) || it->assigned_reg() == _mapping_from.at(i)->assigned_reg(), "stack slots used in _mapping_from must be disjoint to _mapping_to");
+}
+}
+#endif // ASSERT
+// mark assigned_reg and assigned_regHi of the interval as blocked
+void MoveResolver::block_registers(Interval* it) {
+int reg = it->assigned_reg();
+if (reg < LinearScan::nof_regs) {
+assert(_multiple_reads_allowed || register_blocked(reg) == 0, "register already marked as used");
+set_register_blocked(reg, 1);
+}
+reg = it->assigned_regHi();
+if (reg != LinearScan::any_reg && reg < LinearScan::nof_regs) {
+assert(_multiple_reads_allowed || register_blocked(reg) == 0, "register already marked as used");
+set_register_blocked(reg, 1);
+}
+}
+// mark assigned_reg and assigned_regHi of the interval as unblocked
+void MoveResolver::unblock_registers(Interval* it) {
+int reg = it->assigned_reg();
+if (reg < LinearScan::nof_regs) {
+assert(register_blocked(reg) > 0, "register already marked as unused");
+set_register_blocked(reg, -1);
+}
+reg = it->assigned_regHi();
+if (reg != LinearScan::any_reg && reg < LinearScan::nof_regs) {
+assert(register_blocked(reg) > 0, "register already marked as unused");
+set_register_blocked(reg, -1);
+}
+}
+// check if assigned_reg and assigned_regHi of the to-interval are not blocked (or only blocked by from)
+bool MoveResolver::save_to_process_move(Interval* from, Interval* to) {
+int from_reg = -1;
+int from_regHi = -1;
+if (from != NULL) {
+from_reg = from->assigned_reg();
+from_regHi = from->assigned_regHi();
+}
+int reg = to->assigned_reg();
+if (reg < LinearScan::nof_regs) {
+if (register_blocked(reg) > 1 || (register_blocked(reg) == 1 && reg != from_reg && reg != from_regHi)) {
+return false;
+}
+}
+reg = to->assigned_regHi();
+if (reg != LinearScan::any_reg && reg < LinearScan::nof_regs) {
+if (register_blocked(reg) > 1 || (register_blocked(reg) == 1 && reg != from_reg && reg != from_regHi)) {
+return false;
+}
+}
+return true;
+}
+void MoveResolver::create_insertion_buffer(LIR_List* list) {
+assert(!_insertion_buffer.initialized(), "overwriting existing buffer");
+_insertion_buffer.init(list);
+}
+void MoveResolver::append_insertion_buffer() {
+if (_insertion_buffer.initialized()) {
+_insertion_buffer.lir_list()->append(&_insertion_buffer);
+}
+assert(!_insertion_buffer.initialized(), "must be uninitialized now");
+_insert_list = NULL;
+_insert_idx = -1;
+}
+void MoveResolver::insert_move(Interval* from_interval, Interval* to_interval) {
+assert(from_interval->reg_num() != to_interval->reg_num(), "from and to interval equal");
+assert(from_interval->type() == to_interval->type(), "move between different types");
+assert(_insert_list != NULL && _insert_idx != -1, "must setup insert position first");
+assert(_insertion_buffer.lir_list() == _insert_list, "wrong insertion buffer");
+LIR_Opr from_opr = LIR_OprFact::virtual_register(from_interval->reg_num(), from_interval->type());
+LIR_Opr to_opr = LIR_OprFact::virtual_register(to_interval->reg_num(), to_interval->type());
+if (!_multiple_reads_allowed) {
+// the last_use flag is an optimization for FPU stack allocation. When the same
+// input interval is used in more than one move, then it is too difficult to determine
+// if this move is really the last use.
+from_opr = from_opr->make_last_use();
+}
+_insertion_buffer.move(_insert_idx, from_opr, to_opr);
+TRACE_LINEAR_SCAN(4, tty->print_cr("MoveResolver: inserted move from register %d (%d, %d) to %d (%d, %d)", from_interval->reg_num(), from_interval->assigned_reg(), from_interval->assigned_regHi(), to_interval->reg_num(), to_interval->assigned_reg(), to_interval->assigned_regHi()));
+}
+void MoveResolver::insert_move(LIR_Opr from_opr, Interval* to_interval) {
+assert(from_opr->type() == to_interval->type(), "move between different types");
+assert(_insert_list != NULL && _insert_idx != -1, "must setup insert position first");
+assert(_insertion_buffer.lir_list() == _insert_list, "wrong insertion buffer");
+LIR_Opr to_opr = LIR_OprFact::virtual_register(to_interval->reg_num(), to_interval->type());
+_insertion_buffer.move(_insert_idx, from_opr, to_opr);
+TRACE_LINEAR_SCAN(4, tty->print("MoveResolver: inserted move from constant "); from_opr->print(); tty->print_cr("  to %d (%d, %d)", to_interval->reg_num(), to_interval->assigned_reg(), to_interval->assigned_regHi()));
+}
+void MoveResolver::resolve_mappings() {
+TRACE_LINEAR_SCAN(4, tty->print_cr("MoveResolver: resolving mappings for Block B%d, index %d", _insert_list->block() != NULL ? _insert_list->block()->block_id() : -1, _insert_idx));
+DEBUG_ONLY(verify_before_resolve());
+// Block all registers that are used as input operands of a move.
+// When a register is blocked, no move to this register is emitted.
+// This is necessary for detecting cycles in moves.
+int i;
+for (i = _mapping_from.length() - 1; i >= 0; i--) {
+Interval* from_interval = _mapping_from.at(i);
+if (from_interval != NULL) {
+block_registers(from_interval);
+}
+}
+int spill_candidate = -1;
+while (_mapping_from.length() > 0) {
+bool processed_interval = false;
+for (i = _mapping_from.length() - 1; i >= 0; i--) {
+Interval* from_interval = _mapping_from.at(i);
+Interval* to_interval = _mapping_to.at(i);
+if (save_to_process_move(from_interval, to_interval)) {
+// this inverval can be processed because target is free
+if (from_interval != NULL) {
+insert_move(from_interval, to_interval);
+unblock_registers(from_interval);
+} else {
+insert_move(_mapping_from_opr.at(i), to_interval);
+}
+_mapping_from.remove_at(i);
+_mapping_from_opr.remove_at(i);
+_mapping_to.remove_at(i);
+processed_interval = true;
+} else if (from_interval != NULL && from_interval->assigned_reg() < LinearScan::nof_regs) {
+// this interval cannot be processed now because target is not free
+// it starts in a register, so it is a possible candidate for spilling
+spill_candidate = i;
+}
+}
+if (!processed_interval) {
+// no move could be processed because there is a cycle in the move list
+// (e.g. r1 -> r2, r2 -> r1), so one interval must be spilled to memory
+assert(spill_candidate != -1, "no interval in register for spilling found");
+// create a new spill interval and assign a stack slot to it
+Interval* from_interval = _mapping_from.at(spill_candidate);
+Interval* spill_interval = new Interval(-1);
+spill_interval->set_type(from_interval->type());
+// add a dummy range because real position is difficult to calculate
+// Note: this range is a special case when the integrity of the allocation is checked
+spill_interval->add_range(1, 2);
+//       do not allocate a new spill slot for temporary interval, but
+//       use spill slot assigned to from_interval. Otherwise moves from
+//       one stack slot to another can happen (not allowed by LIR_Assembler
+int spill_slot = from_interval->canonical_spill_slot();
+if (spill_slot < 0) {
+spill_slot = allocator()->allocate_spill_slot(type2spill_size[spill_interval->type()] == 2);
+from_interval->set_canonical_spill_slot(spill_slot);
+}
+spill_interval->assign_reg(spill_slot);
+allocator()->append_interval(spill_interval);
+TRACE_LINEAR_SCAN(4, tty->print_cr("created new Interval %d for spilling", spill_interval->reg_num()));
+// insert a move from register to stack and update the mapping
+insert_move(from_interval, spill_interval);
+_mapping_from.at_put(spill_candidate, spill_interval);
+unblock_registers(from_interval);
+}
+}
+// reset to default value
+_multiple_reads_allowed = false;
+// check that all intervals have been processed
+DEBUG_ONLY(check_empty());
+}
+void MoveResolver::set_insert_position(LIR_List* insert_list, int insert_idx) {
+TRACE_LINEAR_SCAN(4, tty->print_cr("MoveResolver: setting insert position to Block B%d, index %d", insert_list->block() != NULL ? insert_list->block()->block_id() : -1, insert_idx));
+assert(_insert_list == NULL && _insert_idx == -1, "use move_insert_position instead of set_insert_position when data already set");
+create_insertion_buffer(insert_list);
+_insert_list = insert_list;
+_insert_idx = insert_idx;
+}
+void MoveResolver::move_insert_position(LIR_List* insert_list, int insert_idx) {
+TRACE_LINEAR_SCAN(4, tty->print_cr("MoveResolver: moving insert position to Block B%d, index %d", insert_list->block() != NULL ? insert_list->block()->block_id() : -1, insert_idx));
+if (_insert_list != NULL && (insert_list != _insert_list || insert_idx != _insert_idx)) {
+// insert position changed -> resolve current mappings
+resolve_mappings();
+}
+if (insert_list != _insert_list) {
+// block changed -> append insertion_buffer because it is
+// bound to a specific block and create a new insertion_buffer
+append_insertion_buffer();
+create_insertion_buffer(insert_list);
+}
+_insert_list = insert_list;
+_insert_idx = insert_idx;
+}
+void MoveResolver::add_mapping(Interval* from_interval, Interval* to_interval) {
+TRACE_LINEAR_SCAN(4, tty->print_cr("MoveResolver: adding mapping from %d (%d, %d) to %d (%d, %d)", from_interval->reg_num(), from_interval->assigned_reg(), from_interval->assigned_regHi(), to_interval->reg_num(), to_interval->assigned_reg(), to_interval->assigned_regHi()));
+_mapping_from.append(from_interval);
+_mapping_from_opr.append(LIR_OprFact::illegalOpr);
+_mapping_to.append(to_interval);
+}
+void MoveResolver::add_mapping(LIR_Opr from_opr, Interval* to_interval) {
+TRACE_LINEAR_SCAN(4, tty->print("MoveResolver: adding mapping from "); from_opr->print(); tty->print_cr(" to %d (%d, %d)", to_interval->reg_num(), to_interval->assigned_reg(), to_interval->assigned_regHi()));
+assert(from_opr->is_constant(), "only for constants");
+_mapping_from.append(NULL);
+_mapping_from_opr.append(from_opr);
+_mapping_to.append(to_interval);
+}
+void MoveResolver::resolve_and_append_moves() {
+if (has_mappings()) {
+resolve_mappings();
+}
+append_insertion_buffer();
+}
+// **** Implementation of Range *************************************
+Range::Range(int from, int to, Range* next) :
+_from(from),
+_to(to),
+_next(next)
+{
+}
+// initialize sentinel
+Range* Range::_end = NULL;
+void Range::initialize() {
+_end = new Range(max_jint, max_jint, NULL);
+}
+int Range::intersects_at(Range* r2) const {
+const Range* r1 = this;
+assert(r1 != NULL && r2 != NULL, "null ranges not allowed");
+assert(r1 != _end && r2 != _end, "empty ranges not allowed");
+do {
+if (r1->from() < r2->from()) {
+if (r1->to() <= r2->from()) {
+r1 = r1->next(); if (r1 == _end) return -1;
+} else {
+return r2->from();
+}
+} else if (r2->from() < r1->from()) {
+if (r2->to() <= r1->from()) {
+r2 = r2->next(); if (r2 == _end) return -1;
+} else {
+return r1->from();
+}
+} else { // r1->from() == r2->from()
+if (r1->from() == r1->to()) {
+r1 = r1->next(); if (r1 == _end) return -1;
+} else if (r2->from() == r2->to()) {
+r2 = r2->next(); if (r2 == _end) return -1;
+} else {
+return r1->from();
+}
+}
+} while (true);
+}
+#ifndef PRODUCT
+void Range::print(outputStream* out) const {
+out->print("[%d, %d[ ", _from, _to);
+}
+#endif
+// **** Implementation of Interval **********************************
+// initialize sentinel
+Interval* Interval::_end = NULL;
+void Interval::initialize() {
+Range::initialize();
+_end = new Interval(-1);
+}
+Interval::Interval(int reg_num) :
+_reg_num(reg_num),
+_type(T_ILLEGAL),
+_first(Range::end()),
+_use_pos_and_kinds(12),
+_current(Range::end()),
+_next(_end),
+_state(invalidState),
+_assigned_reg(LinearScan::any_reg),
+_assigned_regHi(LinearScan::any_reg),
+_cached_to(-1),
+_cached_opr(LIR_OprFact::illegalOpr),
+_cached_vm_reg(VMRegImpl::Bad()),
+_split_children(0),
+_canonical_spill_slot(-1),
+_insert_move_when_activated(false),
+_register_hint(NULL),
+_spill_state(noDefinitionFound),
+_spill_definition_pos(-1)
+{
+_split_parent = this;
+_current_split_child = this;
+}
+int Interval::calc_to() {
+assert(_first != Range::end(), "interval has no range");
+Range* r = _first;
+while (r->next() != Range::end()) {
+r = r->next();
+}
+return r->to();
+}
+#ifdef ASSERT
+// consistency check of split-children
+void Interval::check_split_children() {
+if (_split_children.length() > 0) {
+assert(is_split_parent(), "only split parents can have children");
+for (int i = 0; i < _split_children.length(); i++) {
+Interval* i1 = _split_children.at(i);
+assert(i1->split_parent() == this, "not a split child of this interval");
+assert(i1->type() == type(), "must be equal for all split children");
+assert(i1->canonical_spill_slot() == canonical_spill_slot(), "must be equal for all split children");
+for (int j = i + 1; j < _split_children.length(); j++) {
+Interval* i2 = _split_children.at(j);
+assert(i1->reg_num() != i2->reg_num(), "same register number");
+if (i1->from() < i2->from()) {
+assert(i1->to() <= i2->from() && i1->to() < i2->to(), "intervals overlapping");
+} else {
+assert(i2->from() < i1->from(), "intervals start at same op_id");
+assert(i2->to() <= i1->from() && i2->to() < i1->to(), "intervals overlapping");
+}
+}
+}
+}
+}
+#endif // ASSERT
+Interval* Interval::register_hint(bool search_split_child) const {
+if (!search_split_child) {
+return _register_hint;
+}
+if (_register_hint != NULL) {
+assert(_register_hint->is_split_parent(), "ony split parents are valid hint registers");
+if (_register_hint->assigned_reg() >= 0 && _register_hint->assigned_reg() < LinearScan::nof_regs) {
+return _register_hint;
+} else if (_register_hint->_split_children.length() > 0) {
+// search the first split child that has a register assigned
+int len = _register_hint->_split_children.length();
+for (int i = 0; i < len; i++) {
+Interval* cur = _register_hint->_split_children.at(i);
+if (cur->assigned_reg() >= 0 && cur->assigned_reg() < LinearScan::nof_regs) {
+return cur;
+}
+}
+}
+}
+// no hint interval found that has a register assigned
+return NULL;
+}
+Interval* Interval::split_child_at_op_id(int op_id, LIR_OpVisitState::OprMode mode) {
+assert(is_split_parent(), "can only be called for split parents");
+assert(op_id >= 0, "invalid op_id (method can not be called for spill moves)");
+Interval* result;
+if (_split_children.length() == 0) {
+result = this;
+} else {
+result = NULL;
+int len = _split_children.length();
+// in outputMode, the end of the interval (op_id == cur->to()) is not valid
+int to_offset = (mode == LIR_OpVisitState::outputMode ? 0 : 1);
+int i;
+for (i = 0; i < len; i++) {
+Interval* cur = _split_children.at(i);
+if (cur->from() <= op_id && op_id < cur->to() + to_offset) {
+if (i > 0) {
+// exchange current split child to start of list (faster access for next call)
+_split_children.at_put(i, _split_children.at(0));
+_split_children.at_put(0, cur);
+}
+// interval found
+result = cur;
+break;
+}
+}
+#ifdef ASSERT
+for (i = 0; i < len; i++) {
+Interval* tmp = _split_children.at(i);
+if (tmp != result && tmp->from() <= op_id && op_id < tmp->to() + to_offset) {
+tty->print_cr("two valid result intervals found for op_id %d: %d and %d", op_id, result->reg_num(), tmp->reg_num());
+result->print();
+tmp->print();
+assert(false, "two valid result intervals found");
+}
+}
+#endif
+}
+assert(result != NULL, "no matching interval found");
+assert(result->covers(op_id, mode), "op_id not covered by interval");
+return result;
+}
+// returns the last split child that ends before the given op_id
+Interval* Interval::split_child_before_op_id(int op_id) {
+assert(op_id >= 0, "invalid op_id");
+Interval* parent = split_parent();
+Interval* result = NULL;
+int len = parent->_split_children.length();
+assert(len > 0, "no split children available");
+for (int i = len - 1; i >= 0; i--) {
+Interval* cur = parent->_split_children.at(i);
+if (cur->to() <= op_id && (result == NULL || result->to() < cur->to())) {
+result = cur;
+}
+}
+assert(result != NULL, "no split child found");
+return result;
+}
+// checks if op_id is covered by any split child
+bool Interval::split_child_covers(int op_id, LIR_OpVisitState::OprMode mode) {
+assert(is_split_parent(), "can only be called for split parents");
+assert(op_id >= 0, "invalid op_id (method can not be called for spill moves)");
+if (_split_children.length() == 0) {
+// simple case if interval was not split
+return covers(op_id, mode);
+} else {
+// extended case: check all split children
+int len = _split_children.length();
+for (int i = 0; i < len; i++) {
+Interval* cur = _split_children.at(i);
+if (cur->covers(op_id, mode)) {
+return true;
+}
+}
+return false;
+}
+}
+// Note: use positions are sorted descending -> first use has highest index
+int Interval::first_usage(IntervalUseKind min_use_kind) const {
+assert(LinearScan::is_virtual_interval(this), "cannot access use positions for fixed intervals");
+for (int i = _use_pos_and_kinds.length() - 2; i >= 0; i -= 2) {
+if (_use_pos_and_kinds.at(i + 1) >= min_use_kind) {
+return _use_pos_and_kinds.at(i);
+}
+}
+return max_jint;
+}
+int Interval::next_usage(IntervalUseKind min_use_kind, int from) const {
+assert(LinearScan::is_virtual_interval(this), "cannot access use positions for fixed intervals");
+for (int i = _use_pos_and_kinds.length() - 2; i >= 0; i -= 2) {
+if (_use_pos_and_kinds.at(i) >= from && _use_pos_and_kinds.at(i + 1) >= min_use_kind) {
+return _use_pos_and_kinds.at(i);
+}
+}
+return max_jint;
+}
+int Interval::next_usage_exact(IntervalUseKind exact_use_kind, int from) const {
+assert(LinearScan::is_virtual_interval(this), "cannot access use positions for fixed intervals");
+for (int i = _use_pos_and_kinds.length() - 2; i >= 0; i -= 2) {
+if (_use_pos_and_kinds.at(i) >= from && _use_pos_and_kinds.at(i + 1) == exact_use_kind) {
+return _use_pos_and_kinds.at(i);
+}
+}
+return max_jint;
+}
+int Interval::previous_usage(IntervalUseKind min_use_kind, int from) const {
+assert(LinearScan::is_virtual_interval(this), "cannot access use positions for fixed intervals");
+int prev = 0;
+for (int i = _use_pos_and_kinds.length() - 2; i >= 0; i -= 2) {
+if (_use_pos_and_kinds.at(i) > from) {
+return prev;
+}
+if (_use_pos_and_kinds.at(i + 1) >= min_use_kind) {
+prev = _use_pos_and_kinds.at(i);
+}
+}
+return prev;
+}
+void Interval::add_use_pos(int pos, IntervalUseKind use_kind) {
+assert(covers(pos, LIR_OpVisitState::inputMode), "use position not covered by live range");
+// do not add use positions for precolored intervals because
+// they are never used
+if (use_kind != noUse && reg_num() >= LIR_OprDesc::vreg_base) {
+#ifdef ASSERT
+assert(_use_pos_and_kinds.length() % 2 == 0, "must be");
+for (int i = 0; i < _use_pos_and_kinds.length(); i += 2) {
+assert(pos <= _use_pos_and_kinds.at(i), "already added a use-position with lower position");
+assert(_use_pos_and_kinds.at(i + 1) >= firstValidKind && _use_pos_and_kinds.at(i + 1) <= lastValidKind, "invalid use kind");
+if (i > 0) {
+assert(_use_pos_and_kinds.at(i) < _use_pos_and_kinds.at(i - 2), "not sorted descending");
+}
+}
+#endif
+// Note: add_use is called in descending order, so list gets sorted
+//       automatically by just appending new use positions
+int len = _use_pos_and_kinds.length();
+if (len == 0 || _use_pos_and_kinds.at(len - 2) > pos) {
+_use_pos_and_kinds.append(pos);
+_use_pos_and_kinds.append(use_kind);
+} else if (_use_pos_and_kinds.at(len - 1) < use_kind) {
+assert(_use_pos_and_kinds.at(len - 2) == pos, "list not sorted correctly");
+_use_pos_and_kinds.at_put(len - 1, use_kind);
+}
+}
+}
+void Interval::add_range(int from, int to) {
+assert(from < to, "invalid range");
+assert(first() == Range::end() || to < first()->next()->from(), "not inserting at begin of interval");
+assert(from <= first()->to(), "not inserting at begin of interval");
+if (first()->from() <= to) {
+// join intersecting ranges
+first()->set_from(MIN2(from, first()->from()));
+first()->set_to  (MAX2(to,   first()->to()));
+} else {
+// insert new range
+_first = new Range(from, to, first());
+}
+}
+Interval* Interval::new_split_child() {
+// allocate new interval
+Interval* result = new Interval(-1);
+result->set_type(type());
+Interval* parent = split_parent();
+result->_split_parent = parent;
+result->set_register_hint(parent);
+// insert new interval in children-list of parent
+if (parent->_split_children.length() == 0) {
+assert(is_split_parent(), "list must be initialized at first split");
+parent->_split_children = IntervalList(4);
+parent->_split_children.append(this);
+}
+parent->_split_children.append(result);
+return result;
+}
+// split this interval at the specified position and return
+// the remainder as a new interval.
+//
+// when an interval is split, a bi-directional link is established between the original interval
+// (the split parent) and the intervals that are split off this interval (the split children)
+// When a split child is split again, the new created interval is also a direct child
+// of the original parent (there is no tree of split children stored, but a flat list)
+// All split children are spilled to the same stack slot (stored in _canonical_spill_slot)
+//
+// Note: The new interval has no valid reg_num
+Interval* Interval::split(int split_pos) {
+assert(LinearScan::is_virtual_interval(this), "cannot split fixed intervals");
+// allocate new interval
+Interval* result = new_split_child();
+// split the ranges
+Range* prev = NULL;
+Range* cur = _first;
+while (cur != Range::end() && cur->to() <= split_pos) {
+prev = cur;
+cur = cur->next();
+}
+assert(cur != Range::end(), "split interval after end of last range");
+if (cur->from() < split_pos) {
+result->_first = new Range(split_pos, cur->to(), cur->next());
+cur->set_to(split_pos);
+cur->set_next(Range::end());
+} else {
+assert(prev != NULL, "split before start of first range");
+result->_first = cur;
+prev->set_next(Range::end());
+}
+result->_current = result->_first;
+_cached_to = -1; // clear cached value
+// split list of use positions
+int total_len = _use_pos_and_kinds.length();
+int start_idx = total_len - 2;
+while (start_idx >= 0 && _use_pos_and_kinds.at(start_idx) < split_pos) {
+start_idx -= 2;
+}
+intStack new_use_pos_and_kinds(total_len - start_idx);
+int i;
+for (i = start_idx + 2; i < total_len; i++) {
+new_use_pos_and_kinds.append(_use_pos_and_kinds.at(i));
+}
+_use_pos_and_kinds.truncate(start_idx + 2);
+result->_use_pos_and_kinds = _use_pos_and_kinds;
+_use_pos_and_kinds = new_use_pos_and_kinds;
+#ifdef ASSERT
+assert(_use_pos_and_kinds.length() % 2 == 0, "must have use kind for each use pos");
+assert(result->_use_pos_and_kinds.length() % 2 == 0, "must have use kind for each use pos");
+assert(_use_pos_and_kinds.length() + result->_use_pos_and_kinds.length() == total_len, "missed some entries");
+for (i = 0; i < _use_pos_and_kinds.length(); i += 2) {
+assert(_use_pos_and_kinds.at(i) < split_pos, "must be");
+assert(_use_pos_and_kinds.at(i + 1) >= firstValidKind && _use_pos_and_kinds.at(i + 1) <= lastValidKind, "invalid use kind");
+}
+for (i = 0; i < result->_use_pos_and_kinds.length(); i += 2) {
+assert(result->_use_pos_and_kinds.at(i) >= split_pos, "must be");
+assert(result->_use_pos_and_kinds.at(i + 1) >= firstValidKind && result->_use_pos_and_kinds.at(i + 1) <= lastValidKind, "invalid use kind");
+}
+#endif
+return result;
+}
+// split this interval at the specified position and return
+// the head as a new interval (the original interval is the tail)
+//
+// Currently, only the first range can be split, and the new interval
+// must not have split positions
+Interval* Interval::split_from_start(int split_pos) {
+assert(LinearScan::is_virtual_interval(this), "cannot split fixed intervals");
+assert(split_pos > from() && split_pos < to(), "can only split inside interval");
+assert(split_pos > _first->from() && split_pos <= _first->to(), "can only split inside first range");
+assert(first_usage(noUse) > split_pos, "can not split when use positions are present");
+// allocate new interval
+Interval* result = new_split_child();
+// the new created interval has only one range (checked by assertion above),
+// so the splitting of the ranges is very simple
+result->add_range(_first->from(), split_pos);
+if (split_pos == _first->to()) {
+assert(_first->next() != Range::end(), "must not be at end");
+_first = _first->next();
+} else {
+_first->set_from(split_pos);
+}
+return result;
+}
+// returns true if the op_id is inside the interval
+bool Interval::covers(int op_id, LIR_OpVisitState::OprMode mode) const {
+Range* cur  = _first;
+while (cur != Range::end() && cur->to() < op_id) {
+cur = cur->next();
+}
+if (cur != Range::end()) {
+assert(cur->to() != cur->next()->from(), "ranges not separated");
+if (mode == LIR_OpVisitState::outputMode) {
+return cur->from() <= op_id && op_id < cur->to();
+} else {
+return cur->from() <= op_id && op_id <= cur->to();
+}
+}
+return false;
+}
+// returns true if the interval has any hole between hole_from and hole_to
+// (even if the hole has only the length 1)
+bool Interval::has_hole_between(int hole_from, int hole_to) {
+assert(hole_from < hole_to, "check");
+assert(from() <= hole_from && hole_to <= to(), "index out of interval");
+Range* cur  = _first;
+while (cur != Range::end()) {
+assert(cur->to() < cur->next()->from(), "no space between ranges");
+// hole-range starts before this range -> hole
+if (hole_from < cur->from()) {
+return true;
+// hole-range completely inside this range -> no hole
+} else if (hole_to <= cur->to()) {
+return false;
+// overlapping of hole-range with this range -> hole
+} else if (hole_from <= cur->to()) {
+return true;
+}
+cur = cur->next();
+}
+return false;
+}
+#ifndef PRODUCT
+void Interval::print(outputStream* out) const {
+const char* SpillState2Name[] = { "no definition", "no spill store", "one spill store", "store at definition", "start in memory", "no optimization" };
+const char* UseKind2Name[] = { "N", "L", "S", "M" };
+const char* type_name;
+LIR_Opr opr = LIR_OprFact::illegal();
+if (reg_num() < LIR_OprDesc::vreg_base) {
+type_name = "fixed";
+// need a temporary operand for fixed intervals because type() cannot be called
+if (assigned_reg() >= pd_first_cpu_reg && assigned_reg() <= pd_last_cpu_reg) {
+opr = LIR_OprFact::single_cpu(assigned_reg());
+} else if (assigned_reg() >= pd_first_fpu_reg && assigned_reg() <= pd_last_fpu_reg) {
+opr = LIR_OprFact::single_fpu(assigned_reg() - pd_first_fpu_reg);
+#ifdef IA32
+} else if (assigned_reg() >= pd_first_xmm_reg && assigned_reg() <= pd_last_xmm_reg) {
+opr = LIR_OprFact::single_xmm(assigned_reg() - pd_first_xmm_reg);
+#endif
+} else {
+ShouldNotReachHere();
+}
+} else {
+type_name = type2name(type());
+if (assigned_reg() != -1) {
+opr = LinearScan::calc_operand_for_interval(this);
+}
+}
+out->print("%d %s ", reg_num(), type_name);
+if (opr->is_valid()) {
+out->print("\"");
+opr->print(out);
+out->print("\" ");
+}
+out->print("%d %d ", split_parent()->reg_num(), (register_hint(false) != NULL ? register_hint(false)->reg_num() : -1));
+// print ranges
+Range* cur = _first;
+while (cur != Range::end()) {
+cur->print(out);
+cur = cur->next();
+assert(cur != NULL, "range list not closed with range sentinel");
+}
+// print use positions
+int prev = 0;
+assert(_use_pos_and_kinds.length() % 2 == 0, "must be");
+for (int i =_use_pos_and_kinds.length() - 2; i >= 0; i -= 2) {
+assert(_use_pos_and_kinds.at(i + 1) >= firstValidKind && _use_pos_and_kinds.at(i + 1) <= lastValidKind, "invalid use kind");
+assert(prev < _use_pos_and_kinds.at(i), "use positions not sorted");
+out->print("%d %s ", _use_pos_and_kinds.at(i), UseKind2Name[_use_pos_and_kinds.at(i + 1)]);
+prev = _use_pos_and_kinds.at(i);
+}
+out->print(" \"%s\"", SpillState2Name[spill_state()]);
+out->cr();
+}
+#endif
+// **** Implementation of IntervalWalker ****************************
+IntervalWalker::IntervalWalker(LinearScan* allocator, Interval* unhandled_fixed_first, Interval* unhandled_any_first)
+: _compilation(allocator->compilation())
+, _allocator(allocator)
+{
+_unhandled_first[fixedKind] = unhandled_fixed_first;
+_unhandled_first[anyKind]   = unhandled_any_first;
+_active_first[fixedKind]    = Interval::end();
+_inactive_first[fixedKind]  = Interval::end();
+_active_first[anyKind]      = Interval::end();
+_inactive_first[anyKind]    = Interval::end();
+_current_position = -1;
+_current = NULL;
+next_interval();
+}
+// append interval at top of list
+void IntervalWalker::append_unsorted(Interval** list, Interval* interval) {
+interval->set_next(*list); *list = interval;
+}
+// append interval in order of current range from()
+void IntervalWalker::append_sorted(Interval** list, Interval* interval) {
+Interval* prev = NULL;
+Interval* cur  = *list;
+while (cur->current_from() < interval->current_from()) {
+prev = cur; cur = cur->next();
+}
+if (prev == NULL) {
+*list = interval;
+} else {
+prev->set_next(interval);
+}
+interval->set_next(cur);
+}
+void IntervalWalker::append_to_unhandled(Interval** list, Interval* interval) {
+assert(interval->from() >= current()->current_from(), "cannot append new interval before current walk position");
+Interval* prev = NULL;
+Interval* cur  = *list;
+while (cur->from() < interval->from() || (cur->from() == interval->from() && cur->first_usage(noUse) < interval->first_usage(noUse))) {
+prev = cur; cur = cur->next();
+}
+if (prev == NULL) {
+*list = interval;
+} else {
+prev->set_next(interval);
+}
+interval->set_next(cur);
+}
+inline bool IntervalWalker::remove_from_list(Interval** list, Interval* i) {
+while (*list != Interval::end() && *list != i) {
+list = (*list)->next_addr();
+}
+if (*list != Interval::end()) {
+assert(*list == i, "check");
+*list = (*list)->next();
+return true;
+} else {
+return false;
+}
+}
+void IntervalWalker::remove_from_list(Interval* i) {
+bool deleted;
+if (i->state() == activeState) {
+deleted = remove_from_list(active_first_addr(anyKind), i);
+} else {
+assert(i->state() == inactiveState, "invalid state");
+deleted = remove_from_list(inactive_first_addr(anyKind), i);
+}
+assert(deleted, "interval has not been found in list");
+}
+void IntervalWalker::walk_to(IntervalState state, int from) {
+assert (state == activeState || state == inactiveState, "wrong state");
+for_each_interval_kind(kind) {
+Interval** prev = state == activeState ? active_first_addr(kind) : inactive_first_addr(kind);
+Interval* next   = *prev;
+while (next->current_from() <= from) {
+Interval* cur = next;
+next = cur->next();
+bool range_has_changed = false;
+while (cur->current_to() <= from) {
+cur->next_range();
+range_has_changed = true;
+}
+// also handle move from inactive list to active list
+range_has_changed = range_has_changed || (state == inactiveState && cur->current_from() <= from);
+if (range_has_changed) {
+// remove cur from list
+*prev = next;
+if (cur->current_at_end()) {
+// move to handled state (not maintained as a list)
+cur->set_state(handledState);
+interval_moved(cur, kind, state, handledState);
+} else if (cur->current_from() <= from){
+// sort into active list
+append_sorted(active_first_addr(kind), cur);
+cur->set_state(activeState);
+if (*prev == cur) {
+assert(state == activeState, "check");
+prev = cur->next_addr();
+}
+interval_moved(cur, kind, state, activeState);
+} else {
+// sort into inactive list
+append_sorted(inactive_first_addr(kind), cur);
+cur->set_state(inactiveState);
+if (*prev == cur) {
+assert(state == inactiveState, "check");
+prev = cur->next_addr();
+}
+interval_moved(cur, kind, state, inactiveState);
+}
+} else {
+prev = cur->next_addr();
+continue;
+}
+}
+}
+}
+void IntervalWalker::next_interval() {
+IntervalKind kind;
+Interval* any   = _unhandled_first[anyKind];
+Interval* fixed = _unhandled_first[fixedKind];
+if (any != Interval::end()) {
+// intervals may start at same position -> prefer fixed interval
+kind = fixed != Interval::end() && fixed->from() <= any->from() ? fixedKind : anyKind;
+assert (kind == fixedKind && fixed->from() <= any->from() ||
+kind == anyKind   && any->from() <= fixed->from(), "wrong interval!!!");
+assert(any == Interval::end() || fixed == Interval::end() || any->from() != fixed->from() || kind == fixedKind, "if fixed and any-Interval start at same position, fixed must be processed first");
+} else if (fixed != Interval::end()) {
+kind = fixedKind;
+} else {
+_current = NULL; return;
+}
+_current_kind = kind;
+_current = _unhandled_first[kind];
+_unhandled_first[kind] = _current->next();
+_current->set_next(Interval::end());
+_current->rewind_range();
+}
+void IntervalWalker::walk_to(int lir_op_id) {
+assert(_current_position <= lir_op_id, "can not walk backwards");
+while (current() != NULL) {
+bool is_active = current()->from() <= lir_op_id;
+int id = is_active ? current()->from() : lir_op_id;
+TRACE_LINEAR_SCAN(2, if (_current_position < id) { tty->cr(); tty->print_cr("walk_to(%d) **************************************************************", id); })
+// set _current_position prior to call of walk_to
+_current_position = id;
+// call walk_to even if _current_position == id
+walk_to(activeState, id);
+walk_to(inactiveState, id);
+if (is_active) {
+current()->set_state(activeState);
+if (activate_current()) {
+append_sorted(active_first_addr(current_kind()), current());
+interval_moved(current(), current_kind(), unhandledState, activeState);
+}
+next_interval();
+} else {
+return;
+}
+}
+}
+void IntervalWalker::interval_moved(Interval* interval, IntervalKind kind, IntervalState from, IntervalState to) {
+#ifndef PRODUCT
+if (TraceLinearScanLevel >= 4) {
+#define print_state(state) \
+switch(state) {\
+case unhandledState: tty->print("unhandled"); break;\
+case activeState: tty->print("active"); break;\
+case inactiveState: tty->print("inactive"); break;\
+case handledState: tty->print("handled"); break;\
+default: ShouldNotReachHere(); \
+}
+print_state(from); tty->print(" to "); print_state(to);
+tty->fill_to(23);
+interval->print();
+#undef print_state
+}
+#endif
+}
+// **** Implementation of LinearScanWalker **************************
+LinearScanWalker::LinearScanWalker(LinearScan* allocator, Interval* unhandled_fixed_first, Interval* unhandled_any_first)
+: IntervalWalker(allocator, unhandled_fixed_first, unhandled_any_first)
+, _move_resolver(allocator)
+{
+for (int i = 0; i < LinearScan::nof_regs; i++) {
+_spill_intervals[i] = new IntervalList(2);
+}
+}
+inline void LinearScanWalker::init_use_lists(bool only_process_use_pos) {
+for (int i = _first_reg; i <= _last_reg; i++) {
+_use_pos[i] = max_jint;
+if (!only_process_use_pos) {
+_block_pos[i] = max_jint;
+_spill_intervals[i]->clear();
+}
+}
+}
+inline void LinearScanWalker::exclude_from_use(int reg) {
+assert(reg < LinearScan::nof_regs, "interval must have a register assigned (stack slots not allowed)");
+if (reg >= _first_reg && reg <= _last_reg) {
+_use_pos[reg] = 0;
+}
+}
+inline void LinearScanWalker::exclude_from_use(Interval* i) {
+assert(i->assigned_reg() != any_reg, "interval has no register assigned");
+exclude_from_use(i->assigned_reg());
+exclude_from_use(i->assigned_regHi());
+}
+inline void LinearScanWalker::set_use_pos(int reg, Interval* i, int use_pos, bool only_process_use_pos) {
+assert(use_pos != 0, "must use exclude_from_use to set use_pos to 0");
+if (reg >= _first_reg && reg <= _last_reg) {
+if (_use_pos[reg] > use_pos) {
+_use_pos[reg] = use_pos;
+}
+if (!only_process_use_pos) {
+_spill_intervals[reg]->append(i);
+}
+}
+}
+inline void LinearScanWalker::set_use_pos(Interval* i, int use_pos, bool only_process_use_pos) {
+assert(i->assigned_reg() != any_reg, "interval has no register assigned");
+if (use_pos != -1) {
+set_use_pos(i->assigned_reg(), i, use_pos, only_process_use_pos);
+set_use_pos(i->assigned_regHi(), i, use_pos, only_process_use_pos);
+}
+}
+inline void LinearScanWalker::set_block_pos(int reg, Interval* i, int block_pos) {
+if (reg >= _first_reg && reg <= _last_reg) {
+if (_block_pos[reg] > block_pos) {
+_block_pos[reg] = block_pos;
+}
+if (_use_pos[reg] > block_pos) {
+_use_pos[reg] = block_pos;
+}
+}
+}
+inline void LinearScanWalker::set_block_pos(Interval* i, int block_pos) {
+assert(i->assigned_reg() != any_reg, "interval has no register assigned");
+if (block_pos != -1) {
+set_block_pos(i->assigned_reg(), i, block_pos);
+set_block_pos(i->assigned_regHi(), i, block_pos);
+}
+}
+void LinearScanWalker::free_exclude_active_fixed() {
+Interval* list = active_first(fixedKind);
+while (list != Interval::end()) {
+assert(list->assigned_reg() < LinearScan::nof_regs, "active interval must have a register assigned");
+exclude_from_use(list);
+list = list->next();
+}
+}
+void LinearScanWalker::free_exclude_active_any() {
+Interval* list = active_first(anyKind);
+while (list != Interval::end()) {
+exclude_from_use(list);
+list = list->next();
+}
+}
+void LinearScanWalker::free_collect_inactive_fixed(Interval* cur) {
+Interval* list = inactive_first(fixedKind);
+while (list != Interval::end()) {
+if (cur->to() <= list->current_from()) {
+assert(list->current_intersects_at(cur) == -1, "must not intersect");
+set_use_pos(list, list->current_from(), true);
+} else {
+set_use_pos(list, list->current_intersects_at(cur), true);
+}
+list = list->next();
+}
+}
+void LinearScanWalker::free_collect_inactive_any(Interval* cur) {
+Interval* list = inactive_first(anyKind);
+while (list != Interval::end()) {
+set_use_pos(list, list->current_intersects_at(cur), true);
+list = list->next();
+}
+}
+void LinearScanWalker::free_collect_unhandled(IntervalKind kind, Interval* cur) {
+Interval* list = unhandled_first(kind);
+while (list != Interval::end()) {
+set_use_pos(list, list->intersects_at(cur), true);
+if (kind == fixedKind && cur->to() <= list->from()) {
+set_use_pos(list, list->from(), true);
+}
+list = list->next();
+}
+}
+void LinearScanWalker::spill_exclude_active_fixed() {
+Interval* list = active_first(fixedKind);
+while (list != Interval::end()) {
+exclude_from_use(list);
+list = list->next();
+}
+}
+void LinearScanWalker::spill_block_unhandled_fixed(Interval* cur) {
+Interval* list = unhandled_first(fixedKind);
+while (list != Interval::end()) {
+set_block_pos(list, list->intersects_at(cur));
+list = list->next();
+}
+}
+void LinearScanWalker::spill_block_inactive_fixed(Interval* cur) {
+Interval* list = inactive_first(fixedKind);
+while (list != Interval::end()) {
+if (cur->to() > list->current_from()) {
+set_block_pos(list, list->current_intersects_at(cur));
+} else {
+assert(list->current_intersects_at(cur) == -1, "invalid optimization: intervals intersect");
+}
+list = list->next();
+}
+}
+void LinearScanWalker::spill_collect_active_any() {
+Interval* list = active_first(anyKind);
+while (list != Interval::end()) {
+set_use_pos(list, MIN2(list->next_usage(loopEndMarker, _current_position), list->to()), false);
+list = list->next();
+}
+}
+void LinearScanWalker::spill_collect_inactive_any(Interval* cur) {
+Interval* list = inactive_first(anyKind);
+while (list != Interval::end()) {
+if (list->current_intersects(cur)) {
+set_use_pos(list, MIN2(list->next_usage(loopEndMarker, _current_position), list->to()), false);
+}
+list = list->next();
+}
+}
+void LinearScanWalker::insert_move(int op_id, Interval* src_it, Interval* dst_it) {
+// output all moves here. When source and target are equal, the move is
+// optimized away later in assign_reg_nums
+op_id = (op_id + 1) & ~1;
+BlockBegin* op_block = allocator()->block_of_op_with_id(op_id);
+assert(op_id > 0 && allocator()->block_of_op_with_id(op_id - 2) == op_block, "cannot insert move at block boundary");
+// calculate index of instruction inside instruction list of current block
+// the minimal index (for a block with no spill moves) can be calculated because the
+// numbering of instructions is known.
+// When the block already contains spill moves, the index must be increased until the
+// correct index is reached.
+LIR_OpList* list = op_block->lir()->instructions_list();
+int index = (op_id - list->at(0)->id()) / 2;
+assert(list->at(index)->id() <= op_id, "error in calculation");
+while (list->at(index)->id() != op_id) {
+index++;
+assert(0 <= index && index < list->length(), "index out of bounds");
+}
+assert(1 <= index && index < list->length(), "index out of bounds");
+assert(list->at(index)->id() == op_id, "error in calculation");
+// insert new instruction before instruction at position index
+_move_resolver.move_insert_position(op_block->lir(), index - 1);
+_move_resolver.add_mapping(src_it, dst_it);
+}
+int LinearScanWalker::find_optimal_split_pos(BlockBegin* min_block, BlockBegin* max_block, int max_split_pos) {
+int from_block_nr = min_block->linear_scan_number();
+int to_block_nr = max_block->linear_scan_number();
+assert(0 <= from_block_nr && from_block_nr < block_count(), "out of range");
+assert(0 <= to_block_nr && to_block_nr < block_count(), "out of range");
+assert(from_block_nr < to_block_nr, "must cross block boundary");
+// Try to split at end of max_block. If this would be after
+// max_split_pos, then use the begin of max_block
+int optimal_split_pos = max_block->last_lir_instruction_id() + 2;
+if (optimal_split_pos > max_split_pos) {
+optimal_split_pos = max_block->first_lir_instruction_id();
+}
+int min_loop_depth = max_block->loop_depth();
+for (int i = to_block_nr - 1; i >= from_block_nr; i--) {
+BlockBegin* cur = block_at(i);
+if (cur->loop_depth() < min_loop_depth) {
+// block with lower loop-depth found -> split at the end of this block
+min_loop_depth = cur->loop_depth();
+optimal_split_pos = cur->last_lir_instruction_id() + 2;
+}
+}
+assert(optimal_split_pos > allocator()->max_lir_op_id() || allocator()->is_block_begin(optimal_split_pos), "algorithm must move split pos to block boundary");
+return optimal_split_pos;
+}
+int LinearScanWalker::find_optimal_split_pos(Interval* it, int min_split_pos, int max_split_pos, bool do_loop_optimization) {
+int optimal_split_pos = -1;
+if (min_split_pos == max_split_pos) {
+// trivial case, no optimization of split position possible
+TRACE_LINEAR_SCAN(4, tty->print_cr("      min-pos and max-pos are equal, no optimization possible"));
+optimal_split_pos = min_split_pos;
+} else {
+assert(min_split_pos < max_split_pos, "must be true then");
+assert(min_split_pos > 0, "cannot access min_split_pos - 1 otherwise");
+// reason for using min_split_pos - 1: when the minimal split pos is exactly at the
+// beginning of a block, then min_split_pos is also a possible split position.
+// Use the block before as min_block, because then min_block->last_lir_instruction_id() + 2 == min_split_pos
+BlockBegin* min_block = allocator()->block_of_op_with_id(min_split_pos - 1);
+// reason for using max_split_pos - 1: otherwise there would be an assertion failure
+// when an interval ends at the end of the last block of the method
+// (in this case, max_split_pos == allocator()->max_lir_op_id() + 2, and there is no
+// block at this op_id)
+BlockBegin* max_block = allocator()->block_of_op_with_id(max_split_pos - 1);
+assert(min_block->linear_scan_number() <= max_block->linear_scan_number(), "invalid order");
+if (min_block == max_block) {
+// split position cannot be moved to block boundary, so split as late as possible
+TRACE_LINEAR_SCAN(4, tty->print_cr("      cannot move split pos to block boundary because min_pos and max_pos are in same block"));
+optimal_split_pos = max_split_pos;
+} else if (it->has_hole_between(max_split_pos - 1, max_split_pos) && !allocator()->is_block_begin(max_split_pos)) {
+// Do not move split position if the interval has a hole before max_split_pos.
+// Intervals resulting from Phi-Functions have more than one definition (marked
+// as mustHaveRegister) with a hole before each definition. When the register is needed
+// for the second definition, an earlier reloading is unnecessary.
+TRACE_LINEAR_SCAN(4, tty->print_cr("      interval has hole just before max_split_pos, so splitting at max_split_pos"));
+optimal_split_pos = max_split_pos;
+} else {
+// seach optimal block boundary between min_split_pos and max_split_pos
+TRACE_LINEAR_SCAN(4, tty->print_cr("      moving split pos to optimal block boundary between block B%d and B%d", min_block->block_id(), max_block->block_id()));
+if (do_loop_optimization) {
+// Loop optimization: if a loop-end marker is found between min- and max-position,
+// then split before this loop
+int loop_end_pos = it->next_usage_exact(loopEndMarker, min_block->last_lir_instruction_id() + 2);
+TRACE_LINEAR_SCAN(4, tty->print_cr("      loop optimization: loop end found at pos %d", loop_end_pos));
+assert(loop_end_pos > min_split_pos, "invalid order");
+if (loop_end_pos < max_split_pos) {
+// loop-end marker found between min- and max-position
+// if it is not the end marker for the same loop as the min-position, then move
+// the max-position to this loop block.
+// Desired result: uses tagged as shouldHaveRegister inside a loop cause a reloading
+// of the interval (normally, only mustHaveRegister causes a reloading)
+BlockBegin* loop_block = allocator()->block_of_op_with_id(loop_end_pos);
+TRACE_LINEAR_SCAN(4, tty->print_cr("      interval is used in loop that ends in block B%d, so trying to move max_block back from B%d to B%d", loop_block->block_id(), max_block->block_id(), loop_block->block_id()));
+assert(loop_block != min_block, "loop_block and min_block must be different because block boundary is needed between");
+optimal_split_pos = find_optimal_split_pos(min_block, loop_block, loop_block->last_lir_instruction_id() + 2);
+if (optimal_split_pos == loop_block->last_lir_instruction_id() + 2) {
+optimal_split_pos = -1;
+TRACE_LINEAR_SCAN(4, tty->print_cr("      loop optimization not necessary"));
+} else {
+TRACE_LINEAR_SCAN(4, tty->print_cr("      loop optimization successful"));
+}
+}
+}
+if (optimal_split_pos == -1) {
+// not calculated by loop optimization
+optimal_split_pos = find_optimal_split_pos(min_block, max_block, max_split_pos);
+}
+}
+}
+TRACE_LINEAR_SCAN(4, tty->print_cr("      optimal split position: %d", optimal_split_pos));
+return optimal_split_pos;
+}
+/*
+split an interval at the optimal position between min_split_pos and
+max_split_pos in two parts:
+1) the left part has already a location assigned
+2) the right part is sorted into to the unhandled-list
+*/
+void LinearScanWalker::split_before_usage(Interval* it, int min_split_pos, int max_split_pos) {
+TRACE_LINEAR_SCAN(2, tty->print   ("----- splitting interval: "); it->print());
+TRACE_LINEAR_SCAN(2, tty->print_cr("      between %d and %d", min_split_pos, max_split_pos));
+assert(it->from() < min_split_pos,         "cannot split at start of interval");
+assert(current_position() < min_split_pos, "cannot split before current position");
+assert(min_split_pos <= max_split_pos,     "invalid order");
+assert(max_split_pos <= it->to(),          "cannot split after end of interval");
+int optimal_split_pos = find_optimal_split_pos(it, min_split_pos, max_split_pos, true);
+assert(min_split_pos <= optimal_split_pos && optimal_split_pos <= max_split_pos, "out of range");
+assert(optimal_split_pos <= it->to(),  "cannot split after end of interval");
+assert(optimal_split_pos > it->from(), "cannot split at start of interval");
+if (optimal_split_pos == it->to() && it->next_usage(mustHaveRegister, min_split_pos) == max_jint) {
+// the split position would be just before the end of the interval
+// -> no split at all necessary
+TRACE_LINEAR_SCAN(4, tty->print_cr("      no split necessary because optimal split position is at end of interval"));
+return;
+}
+// must calculate this before the actual split is performed and before split position is moved to odd op_id
+bool move_necessary = !allocator()->is_block_begin(optimal_split_pos) && !it->has_hole_between(optimal_split_pos - 1, optimal_split_pos);
+if (!allocator()->is_block_begin(optimal_split_pos)) {
+// move position before actual instruction (odd op_id)
+optimal_split_pos = (optimal_split_pos - 1) | 1;
+}
+TRACE_LINEAR_SCAN(4, tty->print_cr("      splitting at position %d", optimal_split_pos));
+assert(allocator()->is_block_begin(optimal_split_pos) || (optimal_split_pos % 2 == 1), "split pos must be odd when not on block boundary");
+assert(!allocator()->is_block_begin(optimal_split_pos) || (optimal_split_pos % 2 == 0), "split pos must be even on block boundary");
+Interval* split_part = it->split(optimal_split_pos);
+allocator()->append_interval(split_part);
+allocator()->copy_register_flags(it, split_part);
+split_part->set_insert_move_when_activated(move_necessary);
+append_to_unhandled(unhandled_first_addr(anyKind), split_part);
+TRACE_LINEAR_SCAN(2, tty->print_cr("      split interval in two parts (insert_move_when_activated: %d)", move_necessary));
+TRACE_LINEAR_SCAN(2, tty->print   ("      "); it->print());
+TRACE_LINEAR_SCAN(2, tty->print   ("      "); split_part->print());
+}
+/*
+split an interval at the optimal position between min_split_pos and
+max_split_pos in two parts:
+1) the left part has already a location assigned
+2) the right part is always on the stack and therefore ignored in further processing
+*/
+void LinearScanWalker::split_for_spilling(Interval* it) {
+// calculate allowed range of splitting position
+int max_split_pos = current_position();
+int min_split_pos = MAX2(it->previous_usage(shouldHaveRegister, max_split_pos) + 1, it->from());
+TRACE_LINEAR_SCAN(2, tty->print   ("----- splitting and spilling interval: "); it->print());
+TRACE_LINEAR_SCAN(2, tty->print_cr("      between %d and %d", min_split_pos, max_split_pos));
+assert(it->state() == activeState,     "why spill interval that is not active?");
+assert(it->from() <= min_split_pos,    "cannot split before start of interval");
+assert(min_split_pos <= max_split_pos, "invalid order");
+assert(max_split_pos < it->to(),       "cannot split at end end of interval");
+assert(current_position() < it->to(),  "interval must not end before current position");
+if (min_split_pos == it->from()) {
+// the whole interval is never used, so spill it entirely to memory
+TRACE_LINEAR_SCAN(2, tty->print_cr("      spilling entire interval because split pos is at beginning of interval"));
+assert(it->first_usage(shouldHaveRegister) > current_position(), "interval must not have use position before current_position");
+allocator()->assign_spill_slot(it);
+allocator()->change_spill_state(it, min_split_pos);
+// Also kick parent intervals out of register to memory when they have no use
+// position. This avoids short interval in register surrounded by intervals in
+// memory -> avoid useless moves from memory to register and back
+Interval* parent = it;
+while (parent != NULL && parent->is_split_child()) {
+parent = parent->split_child_before_op_id(parent->from());
+if (parent->assigned_reg() < LinearScan::nof_regs) {
+if (parent->first_usage(shouldHaveRegister) == max_jint) {
+// parent is never used, so kick it out of its assigned register
+TRACE_LINEAR_SCAN(4, tty->print_cr("      kicking out interval %d out of its register because it is never used", parent->reg_num()));
+allocator()->assign_spill_slot(parent);
+} else {
+// do not go further back because the register is actually used by the interval
+parent = NULL;
+}
+}
+}
+} else {
+// search optimal split pos, split interval and spill only the right hand part
+int optimal_split_pos = find_optimal_split_pos(it, min_split_pos, max_split_pos, false);
+assert(min_split_pos <= optimal_split_pos && optimal_split_pos <= max_split_pos, "out of range");
+assert(optimal_split_pos < it->to(), "cannot split at end of interval");
+assert(optimal_split_pos >= it->from(), "cannot split before start of interval");
+if (!allocator()->is_block_begin(optimal_split_pos)) {
+// move position before actual instruction (odd op_id)
+optimal_split_pos = (optimal_split_pos - 1) | 1;
+}
+TRACE_LINEAR_SCAN(4, tty->print_cr("      splitting at position %d", optimal_split_pos));
+assert(allocator()->is_block_begin(optimal_split_pos)  || (optimal_split_pos % 2 == 1), "split pos must be odd when not on block boundary");
+assert(!allocator()->is_block_begin(optimal_split_pos) || (optimal_split_pos % 2 == 0), "split pos must be even on block boundary");
+Interval* spilled_part = it->split(optimal_split_pos);
+allocator()->append_interval(spilled_part);
+allocator()->assign_spill_slot(spilled_part);
+allocator()->change_spill_state(spilled_part, optimal_split_pos);
+if (!allocator()->is_block_begin(optimal_split_pos)) {
+TRACE_LINEAR_SCAN(4, tty->print_cr("      inserting move from interval %d to %d", it->reg_num(), spilled_part->reg_num()));
+insert_move(optimal_split_pos, it, spilled_part);
+}
+// the current_split_child is needed later when moves are inserted for reloading
+assert(spilled_part->current_split_child() == it, "overwriting wrong current_split_child");
+spilled_part->make_current_split_child();
+TRACE_LINEAR_SCAN(2, tty->print_cr("      split interval in two parts"));
+TRACE_LINEAR_SCAN(2, tty->print   ("      "); it->print());
+TRACE_LINEAR_SCAN(2, tty->print   ("      "); spilled_part->print());
+}
+}
+void LinearScanWalker::split_stack_interval(Interval* it) {
+int min_split_pos = current_position() + 1;
+int max_split_pos = MIN2(it->first_usage(shouldHaveRegister), it->to());
+split_before_usage(it, min_split_pos, max_split_pos);
+}
+void LinearScanWalker::split_when_partial_register_available(Interval* it, int register_available_until) {
+int min_split_pos = MAX2(it->previous_usage(shouldHaveRegister, register_available_until), it->from() + 1);
+int max_split_pos = register_available_until;
+split_before_usage(it, min_split_pos, max_split_pos);
+}
+void LinearScanWalker::split_and_spill_interval(Interval* it) {
+assert(it->state() == activeState || it->state() == inactiveState, "other states not allowed");
+int current_pos = current_position();
+if (it->state() == inactiveState) {
+// the interval is currently inactive, so no spill slot is needed for now.
+// when the split part is activated, the interval has a new chance to get a register,
+// so in the best case no stack slot is necessary
+assert(it->has_hole_between(current_pos - 1, current_pos + 1), "interval can not be inactive otherwise");
+split_before_usage(it, current_pos + 1, current_pos + 1);
+} else {
+// search the position where the interval must have a register and split
+// at the optimal position before.
+// The new created part is added to the unhandled list and will get a register
+// when it is activated
+int min_split_pos = current_pos + 1;
+int max_split_pos = MIN2(it->next_usage(mustHaveRegister, min_split_pos), it->to());
+split_before_usage(it, min_split_pos, max_split_pos);
+assert(it->next_usage(mustHaveRegister, current_pos) == max_jint, "the remaining part is spilled to stack and therefore has no register");
+split_for_spilling(it);
+}
+}
+int LinearScanWalker::find_free_reg(int reg_needed_until, int interval_to, int hint_reg, int ignore_reg, bool* need_split) {
+int min_full_reg = any_reg;
+int max_partial_reg = any_reg;
+for (int i = _first_reg; i <= _last_reg; i++) {
+if (i == ignore_reg) {
+// this register must be ignored
+} else if (_use_pos[i] >= interval_to) {
+// this register is free for the full interval
+if (min_full_reg == any_reg || i == hint_reg || (_use_pos[i] < _use_pos[min_full_reg] && min_full_reg != hint_reg)) {
+min_full_reg = i;
+}
+} else if (_use_pos[i] > reg_needed_until) {
+// this register is at least free until reg_needed_until
+if (max_partial_reg == any_reg || i == hint_reg || (_use_pos[i] > _use_pos[max_partial_reg] && max_partial_reg != hint_reg)) {
+max_partial_reg = i;
+}
+}
+}
+if (min_full_reg != any_reg) {
+return min_full_reg;
+} else if (max_partial_reg != any_reg) {
+*need_split = true;
+return max_partial_reg;
+} else {
+return any_reg;
+}
+}
+int LinearScanWalker::find_free_double_reg(int reg_needed_until, int interval_to, int hint_reg, bool* need_split) {
+assert((_last_reg - _first_reg + 1) % 2 == 0, "adjust algorithm");
+int min_full_reg = any_reg;
+int max_partial_reg = any_reg;
+for (int i = _first_reg; i < _last_reg; i+=2) {
+if (_use_pos[i] >= interval_to && _use_pos[i + 1] >= interval_to) {
+// this register is free for the full interval
+if (min_full_reg == any_reg || i == hint_reg || (_use_pos[i] < _use_pos[min_full_reg] && min_full_reg != hint_reg)) {
+min_full_reg = i;
+}
+} else if (_use_pos[i] > reg_needed_until && _use_pos[i + 1] > reg_needed_until) {
+// this register is at least free until reg_needed_until
+if (max_partial_reg == any_reg || i == hint_reg || (_use_pos[i] > _use_pos[max_partial_reg] && max_partial_reg != hint_reg)) {
+max_partial_reg = i;
+}
+}
+}
+if (min_full_reg != any_reg) {
+return min_full_reg;
+} else if (max_partial_reg != any_reg) {
+*need_split = true;
+return max_partial_reg;
+} else {
+return any_reg;
+}
+}
+bool LinearScanWalker::alloc_free_reg(Interval* cur) {
+TRACE_LINEAR_SCAN(2, tty->print("trying to find free register for "); cur->print());
+init_use_lists(true);
+free_exclude_active_fixed();
+free_exclude_active_any();
+free_collect_inactive_fixed(cur);
+free_collect_inactive_any(cur);
+//  free_collect_unhandled(fixedKind, cur);
+assert(unhandled_first(fixedKind) == Interval::end(), "must not have unhandled fixed intervals because all fixed intervals have a use at position 0");
+// _use_pos contains the start of the next interval that has this register assigned
+// (either as a fixed register or a normal allocated register in the past)
+// only intervals overlapping with cur are processed, non-overlapping invervals can be ignored safely
+TRACE_LINEAR_SCAN(4, tty->print_cr("      state of registers:"));
+TRACE_LINEAR_SCAN(4, for (int i = _first_reg; i <= _last_reg; i++) tty->print_cr("      reg %d: use_pos: %d", i, _use_pos[i]));
+int hint_reg, hint_regHi;
+Interval* register_hint = cur->register_hint();
+if (register_hint != NULL) {
+hint_reg = register_hint->assigned_reg();
+hint_regHi = register_hint->assigned_regHi();
+if (allocator()->is_precolored_cpu_interval(register_hint)) {
+assert(hint_reg != any_reg && hint_regHi == any_reg, "must be for fixed intervals");
+hint_regHi = hint_reg + 1;  // connect e.g. eax-edx
+}
+TRACE_LINEAR_SCAN(4, tty->print("      hint registers %d, %d from interval ", hint_reg, hint_regHi); register_hint->print());
+} else {
+hint_reg = any_reg;
+hint_regHi = any_reg;
+}
+assert(hint_reg == any_reg || hint_reg != hint_regHi, "hint reg and regHi equal");
+assert(cur->assigned_reg() == any_reg && cur->assigned_regHi() == any_reg, "register already assigned to interval");
+// the register must be free at least until this position
+int reg_needed_until = cur->from() + 1;
+int interval_to = cur->to();
+bool need_split = false;
+int split_pos = -1;
+int reg = any_reg;
+int regHi = any_reg;
+if (_adjacent_regs) {
+reg = find_free_double_reg(reg_needed_until, interval_to, hint_reg, &need_split);
+regHi = reg + 1;
+if (reg == any_reg) {
+return false;
+}
+split_pos = MIN2(_use_pos[reg], _use_pos[regHi]);
+} else {
+reg = find_free_reg(reg_needed_until, interval_to, hint_reg, any_reg, &need_split);
+if (reg == any_reg) {
+return false;
+}
+split_pos = _use_pos[reg];
+if (_num_phys_regs == 2) {
+regHi = find_free_reg(reg_needed_until, interval_to, hint_regHi, reg, &need_split);
+if (_use_pos[reg] < interval_to && regHi == any_reg) {
+// do not split interval if only one register can be assigned until the split pos
+// (when one register is found for the whole interval, split&spill is only
+// performed for the hi register)
+return false;
+} else if (regHi != any_reg) {
+split_pos = MIN2(split_pos, _use_pos[regHi]);
+// sort register numbers to prevent e.g. a move from eax,ebx to ebx,eax
+if (reg > regHi) {
+int temp = reg;
+reg = regHi;
+regHi = temp;
+}
+}
+}
+}
+cur->assign_reg(reg, regHi);
+TRACE_LINEAR_SCAN(2, tty->print_cr("selected register %d, %d", reg, regHi));
+assert(split_pos > 0, "invalid split_pos");
+if (need_split) {
+// register not available for full interval, so split it
+split_when_partial_register_available(cur, split_pos);
+}
+// only return true if interval is completely assigned
+return _num_phys_regs == 1 || regHi != any_reg;
+}
+int LinearScanWalker::find_locked_reg(int reg_needed_until, int interval_to, int hint_reg, int ignore_reg, bool* need_split) {
+int max_reg = any_reg;
+for (int i = _first_reg; i <= _last_reg; i++) {
+if (i == ignore_reg) {
+// this register must be ignored
+} else if (_use_pos[i] > reg_needed_until) {
+if (max_reg == any_reg || i == hint_reg || (_use_pos[i] > _use_pos[max_reg] && max_reg != hint_reg)) {
+max_reg = i;
+}
+}
+}
+if (max_reg != any_reg && _block_pos[max_reg] <= interval_to) {
+*need_split = true;
+}
+return max_reg;
+}
+int LinearScanWalker::find_locked_double_reg(int reg_needed_until, int interval_to, int hint_reg, bool* need_split) {
+assert((_last_reg - _first_reg + 1) % 2 == 0, "adjust algorithm");
+int max_reg = any_reg;
+for (int i = _first_reg; i < _last_reg; i+=2) {
+if (_use_pos[i] > reg_needed_until && _use_pos[i + 1] > reg_needed_until) {
+if (max_reg == any_reg || _use_pos[i] > _use_pos[max_reg]) {
+max_reg = i;
+}
+}
+}
+if (_block_pos[max_reg] <= interval_to || _block_pos[max_reg + 1] <= interval_to) {
+*need_split = true;
+}
+return max_reg;
+}
+void LinearScanWalker::split_and_spill_intersecting_intervals(int reg, int regHi) {
+assert(reg != any_reg, "no register assigned");
+for (int i = 0; i < _spill_intervals[reg]->length(); i++) {
+Interval* it = _spill_intervals[reg]->at(i);
+remove_from_list(it);
+split_and_spill_interval(it);
+}
+if (regHi != any_reg) {
+IntervalList* processed = _spill_intervals[reg];
+for (int i = 0; i < _spill_intervals[regHi]->length(); i++) {
+Interval* it = _spill_intervals[regHi]->at(i);
+if (processed->index_of(it) == -1) {
+remove_from_list(it);
+split_and_spill_interval(it);
+}
+}
+}
+}
+// Split an Interval and spill it to memory so that cur can be placed in a register
+void LinearScanWalker::alloc_locked_reg(Interval* cur) {
+TRACE_LINEAR_SCAN(2, tty->print("need to split and spill to get register for "); cur->print());
+// collect current usage of registers
+init_use_lists(false);
+spill_exclude_active_fixed();
+//  spill_block_unhandled_fixed(cur);
+assert(unhandled_first(fixedKind) == Interval::end(), "must not have unhandled fixed intervals because all fixed intervals have a use at position 0");
+spill_block_inactive_fixed(cur);
+spill_collect_active_any();
+spill_collect_inactive_any(cur);
+#ifndef PRODUCT
+if (TraceLinearScanLevel >= 4) {
+tty->print_cr("      state of registers:");
+for (int i = _first_reg; i <= _last_reg; i++) {
+tty->print("      reg %d: use_pos: %d, block_pos: %d, intervals: ", i, _use_pos[i], _block_pos[i]);
+for (int j = 0; j < _spill_intervals[i]->length(); j++) {
+tty->print("%d ", _spill_intervals[i]->at(j)->reg_num());
+}
+tty->cr();
+}
+}
+#endif
+// the register must be free at least until this position
+int reg_needed_until = MIN2(cur->first_usage(mustHaveRegister), cur->from() + 1);
+int interval_to = cur->to();
+assert (reg_needed_until > 0 && reg_needed_until < max_jint, "interval has no use");
+int split_pos = 0;
+int use_pos = 0;
+bool need_split = false;
+int reg, regHi;
+if (_adjacent_regs) {
+reg = find_locked_double_reg(reg_needed_until, interval_to, any_reg, &need_split);
+regHi = reg + 1;
+if (reg != any_reg) {
+use_pos = MIN2(_use_pos[reg], _use_pos[regHi]);
+split_pos = MIN2(_block_pos[reg], _block_pos[regHi]);
+}
+} else {
+reg = find_locked_reg(reg_needed_until, interval_to, any_reg, cur->assigned_reg(), &need_split);
+regHi = any_reg;
+if (reg != any_reg) {
+use_pos = _use_pos[reg];
+split_pos = _block_pos[reg];
+if (_num_phys_regs == 2) {
+if (cur->assigned_reg() != any_reg) {
+regHi = reg;
+reg = cur->assigned_reg();
+} else {
+regHi = find_locked_reg(reg_needed_until, interval_to, any_reg, reg, &need_split);
+if (regHi != any_reg) {
+use_pos = MIN2(use_pos, _use_pos[regHi]);
+split_pos = MIN2(split_pos, _block_pos[regHi]);
+}
+}
+if (regHi != any_reg && reg > regHi) {
+// sort register numbers to prevent e.g. a move from eax,ebx to ebx,eax
+int temp = reg;
+reg = regHi;
+regHi = temp;
+}
+}
+}
+}
+if (reg == any_reg || (_num_phys_regs == 2 && regHi == any_reg) || use_pos <= cur->first_usage(mustHaveRegister)) {
+// the first use of cur is later than the spilling position -> spill cur
+TRACE_LINEAR_SCAN(4, tty->print_cr("able to spill current interval. first_usage(register): %d, use_pos: %d", cur->first_usage(mustHaveRegister), use_pos));
+if (cur->first_usage(mustHaveRegister) <= cur->from() + 1) {
+assert(false, "cannot spill interval that is used in first instruction (possible reason: no register found)");
+// assign a reasonable register and do a bailout in product mode to avoid errors
+allocator()->assign_spill_slot(cur);
+BAILOUT("LinearScan: no register found");
+}
+split_and_spill_interval(cur);
+} else {
+TRACE_LINEAR_SCAN(4, tty->print_cr("decided to use register %d, %d", reg, regHi));
+assert(reg != any_reg && (_num_phys_regs == 1 || regHi != any_reg), "no register found");
+assert(split_pos > 0, "invalid split_pos");
+assert(need_split == false || split_pos > cur->from(), "splitting interval at from");
+cur->assign_reg(reg, regHi);
+if (need_split) {
+// register not available for full interval, so split it
+split_when_partial_register_available(cur, split_pos);
+}
+// perform splitting and spilling for all affected intervalls
+split_and_spill_intersecting_intervals(reg, regHi);
+}
+}
+bool LinearScanWalker::no_allocation_possible(Interval* cur) {
+#ifdef IA32
+// fast calculation of intervals that can never get a register because the
+// the next instruction is a call that blocks all registers
+// Note: this does not work if callee-saved registers are available (e.g. on Sparc)
+// check if this interval is the result of a split operation
+// (an interval got a register until this position)
+int pos = cur->from();
+if ((pos & 1) == 1) {
+// the current instruction is a call that blocks all registers
+if (pos < allocator()->max_lir_op_id() && allocator()->has_call(pos + 1)) {
+TRACE_LINEAR_SCAN(4, tty->print_cr("      free register cannot be available because all registers blocked by following call"));
+// safety check that there is really no register available
+assert(alloc_free_reg(cur) == false, "found a register for this interval");
+return true;
+}
+}
+#endif
+return false;
+}
+void LinearScanWalker::init_vars_for_alloc(Interval* cur) {
+BasicType type = cur->type();
+_num_phys_regs = LinearScan::num_physical_regs(type);
+_adjacent_regs = LinearScan::requires_adjacent_regs(type);
+if (pd_init_regs_for_alloc(cur)) {
+// the appropriate register range was selected.
+} else if (type == T_FLOAT || type == T_DOUBLE) {
+_first_reg = pd_first_fpu_reg;
+_last_reg = pd_last_fpu_reg;
+} else {
+_first_reg = pd_first_cpu_reg;
+_last_reg = pd_last_cpu_reg;
+}
+assert(0 <= _first_reg && _first_reg < LinearScan::nof_regs, "out of range");
+assert(0 <= _last_reg && _last_reg < LinearScan::nof_regs, "out of range");
+}
+bool LinearScanWalker::is_move(LIR_Op* op, Interval* from, Interval* to) {
+if (op->code() != lir_move) {
+return false;
+}
+assert(op->as_Op1() != NULL, "move must be LIR_Op1");
+LIR_Opr in = ((LIR_Op1*)op)->in_opr();
+LIR_Opr res = ((LIR_Op1*)op)->result_opr();
+return in->is_virtual() && res->is_virtual() && in->vreg_number() == from->reg_num() && res->vreg_number() == to->reg_num();
+}
+// optimization (especially for phi functions of nested loops):
+// assign same spill slot to non-intersecting intervals
+void LinearScanWalker::combine_spilled_intervals(Interval* cur) {
+if (cur->is_split_child()) {
+// optimization is only suitable for split parents
+return;
+}
+Interval* register_hint = cur->register_hint(false);
+if (register_hint == NULL) {
+// cur is not the target of a move, otherwise register_hint would be set
+return;
+}
+assert(register_hint->is_split_parent(), "register hint must be split parent");
+if (cur->spill_state() != noOptimization || register_hint->spill_state() != noOptimization) {
+// combining the stack slots for intervals where spill move optimization is applied
+// is not benefitial and would cause problems
+return;
+}
+int begin_pos = cur->from();
+int end_pos = cur->to();
+if (end_pos > allocator()->max_lir_op_id() || (begin_pos & 1) != 0 || (end_pos & 1) != 0) {
+// safety check that lir_op_with_id is allowed
+return;
+}
+if (!is_move(allocator()->lir_op_with_id(begin_pos), register_hint, cur) || !is_move(allocator()->lir_op_with_id(end_pos), cur, register_hint)) {
+// cur and register_hint are not connected with two moves
+return;
+}
+Interval* begin_hint = register_hint->split_child_at_op_id(begin_pos, LIR_OpVisitState::inputMode);
+Interval* end_hint = register_hint->split_child_at_op_id(end_pos, LIR_OpVisitState::outputMode);
+if (begin_hint == end_hint || begin_hint->to() != begin_pos || end_hint->from() != end_pos) {
+// register_hint must be split, otherwise the re-writing of use positions does not work
+return;
+}
+assert(begin_hint->assigned_reg() != any_reg, "must have register assigned");
+assert(end_hint->assigned_reg() == any_reg, "must not have register assigned");
+assert(cur->first_usage(mustHaveRegister) == begin_pos, "must have use position at begin of interval because of move");
+assert(end_hint->first_usage(mustHaveRegister) == end_pos, "must have use position at begin of interval because of move");
+if (begin_hint->assigned_reg() < LinearScan::nof_regs) {
+// register_hint is not spilled at begin_pos, so it would not be benefitial to immediately spill cur
+return;
+}
+assert(register_hint->canonical_spill_slot() != -1, "must be set when part of interval was spilled");
+// modify intervals such that cur gets the same stack slot as register_hint
+// delete use positions to prevent the intervals to get a register at beginning
+cur->set_canonical_spill_slot(register_hint->canonical_spill_slot());
+cur->remove_first_use_pos();
+end_hint->remove_first_use_pos();
+}
+// allocate a physical register or memory location to an interval
+bool LinearScanWalker::activate_current() {
+Interval* cur = current();
+bool result = true;
+TRACE_LINEAR_SCAN(2, tty->print   ("+++++ activating interval "); cur->print());
+TRACE_LINEAR_SCAN(4, tty->print_cr("      split_parent: %d, insert_move_when_activated: %d", cur->split_parent()->reg_num(), cur->insert_move_when_activated()));
+if (cur->assigned_reg() >= LinearScan::nof_regs) {
+// activating an interval that has a stack slot assigned -> split it at first use position
+// used for method parameters
+TRACE_LINEAR_SCAN(4, tty->print_cr("      interval has spill slot assigned (method parameter) -> split it before first use"));
+split_stack_interval(cur);
+result = false;
+} else if (allocator()->gen()->is_vreg_flag_set(cur->reg_num(), LIRGenerator::must_start_in_memory)) {
+// activating an interval that must start in a stack slot, but may get a register later
+// used for lir_roundfp: rounding is done by store to stack and reload later
+TRACE_LINEAR_SCAN(4, tty->print_cr("      interval must start in stack slot -> split it before first use"));
+assert(cur->assigned_reg() == any_reg && cur->assigned_regHi() == any_reg, "register already assigned");
+allocator()->assign_spill_slot(cur);
+split_stack_interval(cur);
+result = false;
+} else if (cur->assigned_reg() == any_reg) {
+// interval has not assigned register -> normal allocation
+// (this is the normal case for most intervals)
+TRACE_LINEAR_SCAN(4, tty->print_cr("      normal allocation of register"));
+// assign same spill slot to non-intersecting intervals
+combine_spilled_intervals(cur);
+init_vars_for_alloc(cur);
+if (no_allocation_possible(cur) || !alloc_free_reg(cur)) {
+// no empty register available.
+// split and spill another interval so that this interval gets a register
+alloc_locked_reg(cur);
+}
+// spilled intervals need not be move to active-list
+if (cur->assigned_reg() >= LinearScan::nof_regs) {
+result = false;
+}
+}
+// load spilled values that become active from stack slot to register
+if (cur->insert_move_when_activated()) {
+assert(cur->is_split_child(), "must be");
+assert(cur->current_split_child() != NULL, "must be");
+assert(cur->current_split_child()->reg_num() != cur->reg_num(), "cannot insert move between same interval");
+TRACE_LINEAR_SCAN(4, tty->print_cr("Inserting move from interval %d to %d because insert_move_when_activated is set", cur->current_split_child()->reg_num(), cur->reg_num()));
+insert_move(cur->from(), cur->current_split_child(), cur);
+}
+cur->make_current_split_child();
+return result; // true = interval is moved to active list
+}
+// Implementation of EdgeMoveOptimizer
+EdgeMoveOptimizer::EdgeMoveOptimizer() :
+_edge_instructions(4),
+_edge_instructions_idx(4)
+{
+}
+void EdgeMoveOptimizer::optimize(BlockList* code) {
+EdgeMoveOptimizer optimizer = EdgeMoveOptimizer();
+// ignore the first block in the list (index 0 is not processed)
+for (int i = code->length() - 1; i >= 1; i--) {
+BlockBegin* block = code->at(i);
+if (block->number_of_preds() > 1 && !block->is_set(BlockBegin::exception_entry_flag)) {
+optimizer.optimize_moves_at_block_end(block);
+}
+if (block->number_of_sux() == 2) {
+optimizer.optimize_moves_at_block_begin(block);
+}
+}
+}
+// clear all internal data structures
+void EdgeMoveOptimizer::init_instructions() {
+_edge_instructions.clear();
+_edge_instructions_idx.clear();
+}
+// append a lir-instruction-list and the index of the current operation in to the list
+void EdgeMoveOptimizer::append_instructions(LIR_OpList* instructions, int instructions_idx) {
+_edge_instructions.append(instructions);
+_edge_instructions_idx.append(instructions_idx);
+}
+// return the current operation of the given edge (predecessor or successor)
+LIR_Op* EdgeMoveOptimizer::instruction_at(int edge) {
+LIR_OpList* instructions = _edge_instructions.at(edge);
+int idx = _edge_instructions_idx.at(edge);
+if (idx < instructions->length()) {
+return instructions->at(idx);
+} else {
+return NULL;
+}
+}
+// removes the current operation of the given edge (predecessor or successor)
+void EdgeMoveOptimizer::remove_cur_instruction(int edge, bool decrement_index) {
+LIR_OpList* instructions = _edge_instructions.at(edge);
+int idx = _edge_instructions_idx.at(edge);
+instructions->remove_at(idx);
+if (decrement_index) {
+_edge_instructions_idx.at_put(edge, idx - 1);
+}
+}
+bool EdgeMoveOptimizer::operations_different(LIR_Op* op1, LIR_Op* op2) {
+if (op1 == NULL || op2 == NULL) {
+// at least one block is already empty -> no optimization possible
+return true;
+}
+if (op1->code() == lir_move && op2->code() == lir_move) {
+assert(op1->as_Op1() != NULL, "move must be LIR_Op1");
+assert(op2->as_Op1() != NULL, "move must be LIR_Op1");
+LIR_Op1* move1 = (LIR_Op1*)op1;
+LIR_Op1* move2 = (LIR_Op1*)op2;
+if (move1->info() == move2->info() && move1->in_opr() == move2->in_opr() && move1->result_opr() == move2->result_opr()) {
+// these moves are exactly equal and can be optimized
+return false;
+}
+} else if (op1->code() == lir_fxch && op2->code() == lir_fxch) {
+assert(op1->as_Op1() != NULL, "fxch must be LIR_Op1");
+assert(op2->as_Op1() != NULL, "fxch must be LIR_Op1");
+LIR_Op1* fxch1 = (LIR_Op1*)op1;
+LIR_Op1* fxch2 = (LIR_Op1*)op2;
+if (fxch1->in_opr()->as_jint() == fxch2->in_opr()->as_jint()) {
+// equal FPU stack operations can be optimized
+return false;
+}
+} else if (op1->code() == lir_fpop_raw && op2->code() == lir_fpop_raw) {
+// equal FPU stack operations can be optimized
+return false;
+}
+// no optimization possible
+return true;
+}
+void EdgeMoveOptimizer::optimize_moves_at_block_end(BlockBegin* block) {
+TRACE_LINEAR_SCAN(4, tty->print_cr("optimizing moves at end of block B%d", block->block_id()));
+if (block->is_predecessor(block)) {
+// currently we can't handle this correctly.
+return;
+}
+init_instructions();
+int num_preds = block->number_of_preds();
+assert(num_preds > 1, "do not call otherwise");
+assert(!block->is_set(BlockBegin::exception_entry_flag), "exception handlers not allowed");
+// setup a list with the lir-instructions of all predecessors
+int i;
+for (i = 0; i < num_preds; i++) {
+BlockBegin* pred = block->pred_at(i);
+LIR_OpList* pred_instructions = pred->lir()->instructions_list();
+if (pred->number_of_sux() != 1) {
+// this can happen with switch-statements where multiple edges are between
+// the same blocks.
+return;
+}
+assert(pred->number_of_sux() == 1, "can handle only one successor");
+assert(pred->sux_at(0) == block, "invalid control flow");
+assert(pred_instructions->last()->code() == lir_branch, "block with successor must end with branch");
+assert(pred_instructions->last()->as_OpBranch() != NULL, "branch must be LIR_OpBranch");
+assert(pred_instructions->last()->as_OpBranch()->cond() == lir_cond_always, "block must end with unconditional branch");
+if (pred_instructions->last()->info() != NULL) {
+// can not optimize instructions when debug info is needed
+return;
+}
+// ignore the unconditional branch at the end of the block
+append_instructions(pred_instructions, pred_instructions->length() - 2);
+}
+// process lir-instructions while all predecessors end with the same instruction
+while (true) {
+LIR_Op* op = instruction_at(0);
+for (i = 1; i < num_preds; i++) {
+if (operations_different(op, instruction_at(i))) {
+// these instructions are different and cannot be optimized ->
+// no further optimization possible
+return;
+}
+}
+TRACE_LINEAR_SCAN(4, tty->print("found instruction that is equal in all %d predecessors: ", num_preds); op->print());
+// insert the instruction at the beginning of the current block
+block->lir()->insert_before(1, op);
+// delete the instruction at the end of all predecessors
+for (i = 0; i < num_preds; i++) {
+remove_cur_instruction(i, true);
+}
+}
+}
+void EdgeMoveOptimizer::optimize_moves_at_block_begin(BlockBegin* block) {
+TRACE_LINEAR_SCAN(4, tty->print_cr("optimization moves at begin of block B%d", block->block_id()));
+init_instructions();
+int num_sux = block->number_of_sux();
+LIR_OpList* cur_instructions = block->lir()->instructions_list();
+assert(num_sux == 2, "method should not be called otherwise");
+assert(cur_instructions->last()->code() == lir_branch, "block with successor must end with branch");
+assert(cur_instructions->last()->as_OpBranch() != NULL, "branch must be LIR_OpBranch");
+assert(cur_instructions->last()->as_OpBranch()->cond() == lir_cond_always, "block must end with unconditional branch");
+if (cur_instructions->last()->info() != NULL) {
+// can no optimize instructions when debug info is needed
+return;
+}
+LIR_Op* branch = cur_instructions->at(cur_instructions->length() - 2);
+if (branch->info() != NULL || (branch->code() != lir_branch && branch->code() != lir_cond_float_branch)) {
+// not a valid case for optimization
+// currently, only blocks that end with two branches (conditional branch followed
+// by unconditional branch) are optimized
+return;
+}
+// now it is guaranteed that the block ends with two branch instructions.
+// the instructions are inserted at the end of the block before these two branches
+int insert_idx = cur_instructions->length() - 2;
+int i;
+#ifdef ASSERT
+for (i = insert_idx - 1; i >= 0; i--) {
+LIR_Op* op = cur_instructions->at(i);
+if ((op->code() == lir_branch || op->code() == lir_cond_float_branch) && ((LIR_OpBranch*)op)->block() != NULL) {
+assert(false, "block with two successors can have only two branch instructions");
+}
+}
+#endif
+// setup a list with the lir-instructions of all successors
+for (i = 0; i < num_sux; i++) {
+BlockBegin* sux = block->sux_at(i);
+LIR_OpList* sux_instructions = sux->lir()->instructions_list();
+assert(sux_instructions->at(0)->code() == lir_label, "block must start with label");
+if (sux->number_of_preds() != 1) {
+// this can happen with switch-statements where multiple edges are between
+// the same blocks.
+return;
+}
+assert(sux->pred_at(0) == block, "invalid control flow");
+assert(!sux->is_set(BlockBegin::exception_entry_flag), "exception handlers not allowed");
+// ignore the label at the beginning of the block
+append_instructions(sux_instructions, 1);
+}
+// process lir-instructions while all successors begin with the same instruction
+while (true) {
+LIR_Op* op = instruction_at(0);
+for (i = 1; i < num_sux; i++) {
+if (operations_different(op, instruction_at(i))) {
+// these instructions are different and cannot be optimized ->
+// no further optimization possible
+return;
+}
+}
+TRACE_LINEAR_SCAN(4, tty->print("----- found instruction that is equal in all %d successors: ", num_sux); op->print());
+// insert instruction at end of current block
+block->lir()->insert_before(insert_idx, op);
+insert_idx++;
+// delete the instructions at the beginning of all successors
+for (i = 0; i < num_sux; i++) {
+remove_cur_instruction(i, false);
+}
+}
+}
+// Implementation of ControlFlowOptimizer
+ControlFlowOptimizer::ControlFlowOptimizer() :
+_original_preds(4)
+{
+}
+void ControlFlowOptimizer::optimize(BlockList* code) {
+ControlFlowOptimizer optimizer = ControlFlowOptimizer();
+// push the OSR entry block to the end so that we're not jumping over it.
+BlockBegin* osr_entry = code->at(0)->end()->as_Base()->osr_entry();
+if (osr_entry) {
+int index = osr_entry->linear_scan_number();
+assert(code->at(index) == osr_entry, "wrong index");
+code->remove_at(index);
+code->append(osr_entry);
+}
+optimizer.reorder_short_loops(code);
+optimizer.delete_empty_blocks(code);
+optimizer.delete_unnecessary_jumps(code);
+optimizer.delete_jumps_to_return(code);
+}
+void ControlFlowOptimizer::reorder_short_loop(BlockList* code, BlockBegin* header_block, int header_idx) {
+int i = header_idx + 1;
+int max_end = MIN2(header_idx + ShortLoopSize, code->length());
+while (i < max_end && code->at(i)->loop_depth() >= header_block->loop_depth()) {
+i++;
+}
+if (i == code->length() || code->at(i)->loop_depth() < header_block->loop_depth()) {
+int end_idx = i - 1;
+BlockBegin* end_block = code->at(end_idx);
+if (end_block->number_of_sux() == 1 && end_block->sux_at(0) == header_block) {
+// short loop from header_idx to end_idx found -> reorder blocks such that
+// the header_block is the last block instead of the first block of the loop
+TRACE_LINEAR_SCAN(1, tty->print_cr("Reordering short loop: length %d, header B%d, end B%d",
+end_idx - header_idx + 1,
+header_block->block_id(), end_block->block_id()));
+for (int j = header_idx; j < end_idx; j++) {
+code->at_put(j, code->at(j + 1));
+}
+code->at_put(end_idx, header_block);
+// correct the flags so that any loop alignment occurs in the right place.
+assert(code->at(end_idx)->is_set(BlockBegin::backward_branch_target_flag), "must be backward branch target");
+code->at(end_idx)->clear(BlockBegin::backward_branch_target_flag);
+code->at(header_idx)->set(BlockBegin::backward_branch_target_flag);
+}
+}
+}
+void ControlFlowOptimizer::reorder_short_loops(BlockList* code) {
+for (int i = code->length() - 1; i >= 0; i--) {
+BlockBegin* block = code->at(i);
+if (block->is_set(BlockBegin::linear_scan_loop_header_flag)) {
+reorder_short_loop(code, block, i);
+}
+}
+DEBUG_ONLY(verify(code));
+}
+// only blocks with exactly one successor can be deleted. Such blocks
+// must always end with an unconditional branch to this successor
+bool ControlFlowOptimizer::can_delete_block(BlockBegin* block) {
+if (block->number_of_sux() != 1 || block->number_of_exception_handlers() != 0 || block->is_entry_block()) {
+return false;
+}
+LIR_OpList* instructions = block->lir()->instructions_list();
+assert(instructions->length() >= 2, "block must have label and branch");
+assert(instructions->at(0)->code() == lir_label, "first instruction must always be a label");
+assert(instructions->last()->as_OpBranch() != NULL, "last instrcution must always be a branch");
+assert(instructions->last()->as_OpBranch()->cond() == lir_cond_always, "branch must be unconditional");
+assert(instructions->last()->as_OpBranch()->block() == block->sux_at(0), "branch target must be the successor");
+// block must have exactly one successor
+if (instructions->length() == 2 && instructions->last()->info() == NULL) {
+return true;
+}
+return false;
+}
+// substitute branch targets in all branch-instructions of this blocks
+void ControlFlowOptimizer::substitute_branch_target(BlockBegin* block, BlockBegin* target_from, BlockBegin* target_to) {
+TRACE_LINEAR_SCAN(3, tty->print_cr("Deleting empty block: substituting from B%d to B%d inside B%d", target_from->block_id(), target_to->block_id(), block->block_id()));
+LIR_OpList* instructions = block->lir()->instructions_list();
+assert(instructions->at(0)->code() == lir_label, "first instruction must always be a label");
+for (int i = instructions->length() - 1; i >= 1; i--) {
+LIR_Op* op = instructions->at(i);
+if (op->code() == lir_branch || op->code() == lir_cond_float_branch) {
+assert(op->as_OpBranch() != NULL, "branch must be of type LIR_OpBranch");
+LIR_OpBranch* branch = (LIR_OpBranch*)op;
+if (branch->block() == target_from) {
+branch->change_block(target_to);
+}
+if (branch->ublock() == target_from) {
+branch->change_ublock(target_to);
+}
+}
+}
+}
+void ControlFlowOptimizer::delete_empty_blocks(BlockList* code) {
+int old_pos = 0;
+int new_pos = 0;
+int num_blocks = code->length();
+while (old_pos < num_blocks) {
+BlockBegin* block = code->at(old_pos);
+if (can_delete_block(block)) {
+BlockBegin* new_target = block->sux_at(0);
+// propagate backward branch target flag for correct code alignment
+if (block->is_set(BlockBegin::backward_branch_target_flag)) {
+new_target->set(BlockBegin::backward_branch_target_flag);
+}
+// collect a list with all predecessors that contains each predecessor only once
+// the predecessors of cur are changed during the substitution, so a copy of the
+// predecessor list is necessary
+int j;
+_original_preds.clear();
+for (j = block->number_of_preds() - 1; j >= 0; j--) {
+BlockBegin* pred = block->pred_at(j);
+if (_original_preds.index_of(pred) == -1) {
+_original_preds.append(pred);
+}
+}
+for (j = _original_preds.length() - 1; j >= 0; j--) {
+BlockBegin* pred = _original_preds.at(j);
+substitute_branch_target(pred, block, new_target);
+pred->substitute_sux(block, new_target);
+}
+} else {
+// adjust position of this block in the block list if blocks before
+// have been deleted
+if (new_pos != old_pos) {
+code->at_put(new_pos, code->at(old_pos));
+}
+new_pos++;
+}
+old_pos++;
+}
+code->truncate(new_pos);
+DEBUG_ONLY(verify(code));
+}
+void ControlFlowOptimizer::delete_unnecessary_jumps(BlockList* code) {
+// skip the last block because there a branch is always necessary
+for (int i = code->length() - 2; i >= 0; i--) {
+BlockBegin* block = code->at(i);
+LIR_OpList* instructions = block->lir()->instructions_list();
+LIR_Op* last_op = instructions->last();
+if (last_op->code() == lir_branch) {
+assert(last_op->as_OpBranch() != NULL, "branch must be of type LIR_OpBranch");
+LIR_OpBranch* last_branch = (LIR_OpBranch*)last_op;
+assert(last_branch->block() != NULL, "last branch must always have a block as target");
+assert(last_branch->label() == last_branch->block()->label(), "must be equal");
+if (last_branch->info() == NULL) {
+if (last_branch->block() == code->at(i + 1)) {
+TRACE_LINEAR_SCAN(3, tty->print_cr("Deleting unconditional branch at end of block B%d", block->block_id()));
+// delete last branch instruction
+instructions->truncate(instructions->length() - 1);
+} else {
+LIR_Op* prev_op = instructions->at(instructions->length() - 2);
+if (prev_op->code() == lir_branch || prev_op->code() == lir_cond_float_branch) {
+assert(prev_op->as_OpBranch() != NULL, "branch must be of type LIR_OpBranch");
+LIR_OpBranch* prev_branch = (LIR_OpBranch*)prev_op;
+if (prev_branch->block() == code->at(i + 1) && prev_branch->info() == NULL) {
+TRACE_LINEAR_SCAN(3, tty->print_cr("Negating conditional branch and deleting unconditional branch at end of block B%d", block->block_id()));
+// eliminate a conditional branch to the immediate successor
+prev_branch->change_block(last_branch->block());
+prev_branch->negate_cond();
+instructions->truncate(instructions->length() - 1);
+}
+}
+}
+}
+}
+}
+DEBUG_ONLY(verify(code));
+}
+void ControlFlowOptimizer::delete_jumps_to_return(BlockList* code) {
+#ifdef ASSERT
+BitMap return_converted(BlockBegin::number_of_blocks());
+return_converted.clear();
+#endif
+for (int i = code->length() - 1; i >= 0; i--) {
+BlockBegin* block = code->at(i);
+LIR_OpList* cur_instructions = block->lir()->instructions_list();
+LIR_Op*     cur_last_op = cur_instructions->last();
+assert(cur_instructions->at(0)->code() == lir_label, "first instruction must always be a label");
+if (cur_instructions->length() == 2 && cur_last_op->code() == lir_return) {
+// the block contains only a label and a return
+// if a predecessor ends with an unconditional jump to this block, then the jump
+// can be replaced with a return instruction
+//
+// Note: the original block with only a return statement cannot be deleted completely
+//       because the predecessors might have other (conditional) jumps to this block
+//       -> this may lead to unnecesary return instructions in the final code
+assert(cur_last_op->info() == NULL, "return instructions do not have debug information");
+assert(block->number_of_sux() == 0 ||
+(return_converted.at(block->block_id()) && block->number_of_sux() == 1),
+"blocks that end with return must not have successors");
+assert(cur_last_op->as_Op1() != NULL, "return must be LIR_Op1");
+LIR_Opr return_opr = ((LIR_Op1*)cur_last_op)->in_opr();
+for (int j = block->number_of_preds() - 1; j >= 0; j--) {
+BlockBegin* pred = block->pred_at(j);
+LIR_OpList* pred_instructions = pred->lir()->instructions_list();
+LIR_Op*     pred_last_op = pred_instructions->last();
+if (pred_last_op->code() == lir_branch) {
+assert(pred_last_op->as_OpBranch() != NULL, "branch must be LIR_OpBranch");
+LIR_OpBranch* pred_last_branch = (LIR_OpBranch*)pred_last_op;
+if (pred_last_branch->block() == block && pred_last_branch->cond() == lir_cond_always && pred_last_branch->info() == NULL) {
+// replace the jump to a return with a direct return
+// Note: currently the edge between the blocks is not deleted
+pred_instructions->at_put(pred_instructions->length() - 1, new LIR_Op1(lir_return, return_opr));
+#ifdef ASSERT
+return_converted.set_bit(pred->block_id());
+#endif
+}
+}
+}
+}
+}
+}
+#ifdef ASSERT
+void ControlFlowOptimizer::verify(BlockList* code) {
+for (int i = 0; i < code->length(); i++) {
+BlockBegin* block = code->at(i);
+LIR_OpList* instructions = block->lir()->instructions_list();
+int j;
+for (j = 0; j < instructions->length(); j++) {
+LIR_OpBranch* op_branch = instructions->at(j)->as_OpBranch();
+if (op_branch != NULL) {
+assert(op_branch->block() == NULL || code->index_of(op_branch->block()) != -1, "branch target not valid");
+assert(op_branch->ublock() == NULL || code->index_of(op_branch->ublock()) != -1, "branch target not valid");
+}
+}
+for (j = 0; j < block->number_of_sux() - 1; j++) {
+BlockBegin* sux = block->sux_at(j);
+assert(code->index_of(sux) != -1, "successor not valid");
+}
+for (j = 0; j < block->number_of_preds() - 1; j++) {
+BlockBegin* pred = block->pred_at(j);
+assert(code->index_of(pred) != -1, "successor not valid");
+}
+}
+}
+#endif
+#ifndef PRODUCT
+// Implementation of LinearStatistic
+const char* LinearScanStatistic::counter_name(int counter_idx) {
+switch (counter_idx) {
+case counter_method:          return "compiled methods";
+case counter_fpu_method:      return "methods using fpu";
+case counter_loop_method:     return "methods with loops";
+case counter_exception_method:return "methods with xhandler";
+case counter_loop:            return "loops";
+case counter_block:           return "blocks";
+case counter_loop_block:      return "blocks inside loop";
+case counter_exception_block: return "exception handler entries";
+case counter_interval:        return "intervals";
+case counter_fixed_interval:  return "fixed intervals";
+case counter_range:           return "ranges";
+case counter_fixed_range:     return "fixed ranges";
+case counter_use_pos:         return "use positions";
+case counter_fixed_use_pos:   return "fixed use positions";
+case counter_spill_slots:     return "spill slots";
+// counter for classes of lir instructions
+case counter_instruction:     return "total instructions";
+case counter_label:           return "labels";
+case counter_entry:           return "method entries";
+case counter_return:          return "method returns";
+case counter_call:            return "method calls";
+case counter_move:            return "moves";
+case counter_cmp:             return "compare";
+case counter_cond_branch:     return "conditional branches";
+case counter_uncond_branch:   return "unconditional branches";
+case counter_stub_branch:     return "branches to stub";
+case counter_alu:             return "artithmetic + logic";
+case counter_alloc:           return "allocations";
+case counter_sync:            return "synchronisation";
+case counter_throw:           return "throw";
+case counter_unwind:          return "unwind";
+case counter_typecheck:       return "type+null-checks";
+case counter_fpu_stack:       return "fpu-stack";
+case counter_misc_inst:       return "other instructions";
+case counter_other_inst:      return "misc. instructions";
+// counter for different types of moves
+case counter_move_total:      return "total moves";
+case counter_move_reg_reg:    return "register->register";
+case counter_move_reg_stack:  return "register->stack";
+case counter_move_stack_reg:  return "stack->register";
+case counter_move_stack_stack:return "stack->stack";
+case counter_move_reg_mem:    return "register->memory";
+case counter_move_mem_reg:    return "memory->register";
+case counter_move_const_any:  return "constant->any";
+case blank_line_1:            return "";
+case blank_line_2:            return "";
+default: ShouldNotReachHere(); return "";
+}
+}
+LinearScanStatistic::Counter LinearScanStatistic::base_counter(int counter_idx) {
+if (counter_idx == counter_fpu_method || counter_idx == counter_loop_method || counter_idx == counter_exception_method) {
+return counter_method;
+} else if (counter_idx == counter_loop_block || counter_idx == counter_exception_block) {
+return counter_block;
+} else if (counter_idx >= counter_instruction && counter_idx <= counter_other_inst) {
+return counter_instruction;
+} else if (counter_idx >= counter_move_total && counter_idx <= counter_move_const_any) {
+return counter_move_total;
+}
+return invalid_counter;
+}
+LinearScanStatistic::LinearScanStatistic() {
+for (int i = 0; i < number_of_counters; i++) {
+_counters_sum[i] = 0;
+_counters_max[i] = -1;
+}
+}
+// add the method-local numbers to the total sum
+void LinearScanStatistic::sum_up(LinearScanStatistic &method_statistic) {
+for (int i = 0; i < number_of_counters; i++) {
+_counters_sum[i] += method_statistic._counters_sum[i];
+_counters_max[i] = MAX2(_counters_max[i], method_statistic._counters_sum[i]);
+}
+}
+void LinearScanStatistic::print(const char* title) {
+if (CountLinearScan || TraceLinearScanLevel > 0) {
+tty->cr();
+tty->print_cr("***** LinearScan statistic - %s *****", title);
+for (int i = 0; i < number_of_counters; i++) {
+if (_counters_sum[i] > 0 || _counters_max[i] >= 0) {
+tty->print("%25s: %8d", counter_name(i), _counters_sum[i]);
+if (base_counter(i) != invalid_counter) {
+tty->print("  (%5.1f%%) ", _counters_sum[i] * 100.0 / _counters_sum[base_counter(i)]);
+} else {
+tty->print("           ");
+}
+if (_counters_max[i] >= 0) {
+tty->print("%8d", _counters_max[i]);
+}
+}
+tty->cr();
+}
+}
+}
+void LinearScanStatistic::collect(LinearScan* allocator) {
+inc_counter(counter_method);
+if (allocator->has_fpu_registers()) {
+inc_counter(counter_fpu_method);
+}
+if (allocator->num_loops() > 0) {
+inc_counter(counter_loop_method);
+}
+inc_counter(counter_loop, allocator->num_loops());
+inc_counter(counter_spill_slots, allocator->max_spills());
+int i;
+for (i = 0; i < allocator->interval_count(); i++) {
+Interval* cur = allocator->interval_at(i);
+if (cur != NULL) {
+inc_counter(counter_interval);
+inc_counter(counter_use_pos, cur->num_use_positions());
+if (LinearScan::is_precolored_interval(cur)) {
+inc_counter(counter_fixed_interval);
+inc_counter(counter_fixed_use_pos, cur->num_use_positions());
+}
+Range* range = cur->first();
+while (range != Range::end()) {
+inc_counter(counter_range);
+if (LinearScan::is_precolored_interval(cur)) {
+inc_counter(counter_fixed_range);
+}
+range = range->next();
+}
+}
+}
+bool has_xhandlers = false;
+// Note: only count blocks that are in code-emit order
+for (i = 0; i < allocator->ir()->code()->length(); i++) {
+BlockBegin* cur = allocator->ir()->code()->at(i);
+inc_counter(counter_block);
+if (cur->loop_depth() > 0) {
+inc_counter(counter_loop_block);
+}
+if (cur->is_set(BlockBegin::exception_entry_flag)) {
+inc_counter(counter_exception_block);
+has_xhandlers = true;
+}
+LIR_OpList* instructions = cur->lir()->instructions_list();
+for (int j = 0; j < instructions->length(); j++) {
+LIR_Op* op = instructions->at(j);
+inc_counter(counter_instruction);
+switch (op->code()) {
+case lir_label:           inc_counter(counter_label); break;
+case lir_std_entry:
+case lir_osr_entry:       inc_counter(counter_entry); break;
+case lir_return:          inc_counter(counter_return); break;
+case lir_rtcall:
+case lir_static_call:
+case lir_optvirtual_call:
+case lir_virtual_call:    inc_counter(counter_call); break;
+case lir_move: {
+inc_counter(counter_move);
+inc_counter(counter_move_total);
+LIR_Opr in = op->as_Op1()->in_opr();
+LIR_Opr res = op->as_Op1()->result_opr();
+if (in->is_register()) {
+if (res->is_register()) {
+inc_counter(counter_move_reg_reg);
+} else if (res->is_stack()) {
+inc_counter(counter_move_reg_stack);
+} else if (res->is_address()) {
+inc_counter(counter_move_reg_mem);
+} else {
+ShouldNotReachHere();
+}
+} else if (in->is_stack()) {
+if (res->is_register()) {
+inc_counter(counter_move_stack_reg);
+} else {
+inc_counter(counter_move_stack_stack);
+}
+} else if (in->is_address()) {
+assert(res->is_register(), "must be");
+inc_counter(counter_move_mem_reg);
+} else if (in->is_constant()) {
+inc_counter(counter_move_const_any);
+} else {
+ShouldNotReachHere();
+}
+break;
+}
+case lir_cmp:             inc_counter(counter_cmp); break;
+case lir_branch:
+case lir_cond_float_branch: {
+LIR_OpBranch* branch = op->as_OpBranch();
+if (branch->block() == NULL) {
+inc_counter(counter_stub_branch);
+} else if (branch->cond() == lir_cond_always) {
+inc_counter(counter_uncond_branch);
+} else {
+inc_counter(counter_cond_branch);
+}
+break;
+}
+case lir_neg:
+case lir_add:
+case lir_sub:
+case lir_mul:
+case lir_mul_strictfp:
+case lir_div:
+case lir_div_strictfp:
+case lir_rem:
+case lir_sqrt:
+case lir_sin:
+case lir_cos:
+case lir_abs:
+case lir_log10:
+case lir_log:
+case lir_logic_and:
+case lir_logic_or:
+case lir_logic_xor:
+case lir_shl:
+case lir_shr:
+case lir_ushr:            inc_counter(counter_alu); break;
+case lir_alloc_object:
+case lir_alloc_array:     inc_counter(counter_alloc); break;
+case lir_monaddr:
+case lir_lock:
+case lir_unlock:          inc_counter(counter_sync); break;
+case lir_throw:           inc_counter(counter_throw); break;
+case lir_unwind:          inc_counter(counter_unwind); break;
+case lir_null_check:
+case lir_leal:
+case lir_instanceof:
+case lir_checkcast:
+case lir_store_check:     inc_counter(counter_typecheck); break;
+case lir_fpop_raw:
+case lir_fxch:
+case lir_fld:             inc_counter(counter_fpu_stack); break;
+case lir_nop:
+case lir_push:
+case lir_pop:
+case lir_convert:
+case lir_roundfp:
+case lir_cmove:           inc_counter(counter_misc_inst); break;
+default:                  inc_counter(counter_other_inst); break;
+}
+}
+}
+if (has_xhandlers) {
+inc_counter(counter_exception_method);
+}
+}
+void LinearScanStatistic::compute(LinearScan* allocator, LinearScanStatistic &global_statistic) {
+if (CountLinearScan || TraceLinearScanLevel > 0) {
+LinearScanStatistic local_statistic = LinearScanStatistic();
+local_statistic.collect(allocator);
+global_statistic.sum_up(local_statistic);
+if (TraceLinearScanLevel > 2) {
+local_statistic.print("current local statistic");
+}
+}
+}
+// Implementation of LinearTimers
+LinearScanTimers::LinearScanTimers() {
+for (int i = 0; i < number_of_timers; i++) {
+timer(i)->reset();
+}
+}
+const char* LinearScanTimers::timer_name(int idx) {
+switch (idx) {
+case timer_do_nothing:               return "Nothing (Time Check)";
+case timer_number_instructions:      return "Number Instructions";
+case timer_compute_local_live_sets:  return "Local Live Sets";
+case timer_compute_global_live_sets: return "Global Live Sets";
+case timer_build_intervals:          return "Build Intervals";
+case timer_sort_intervals_before:    return "Sort Intervals Before";
+case timer_allocate_registers:       return "Allocate Registers";
+case timer_resolve_data_flow:        return "Resolve Data Flow";
+case timer_sort_intervals_after:     return "Sort Intervals After";
+case timer_eliminate_spill_moves:    return "Spill optimization";
+case timer_assign_reg_num:           return "Assign Reg Num";
+case timer_allocate_fpu_stack:       return "Allocate FPU Stack";
+case timer_optimize_lir:             return "Optimize LIR";
+default: ShouldNotReachHere();       return "";
+}
+}
+void LinearScanTimers::begin_method() {
+if (TimeEachLinearScan) {
+// reset all timers to measure only current method
+for (int i = 0; i < number_of_timers; i++) {
+timer(i)->reset();
+}
+}
+}
+void LinearScanTimers::end_method(LinearScan* allocator) {
+if (TimeEachLinearScan) {
+double c = timer(timer_do_nothing)->seconds();
+double total = 0;
+for (int i = 1; i < number_of_timers; i++) {
+total += timer(i)->seconds() - c;
+}
+if (total >= 0.0005) {
+// print all information in one line for automatic processing
+tty->print("@"); allocator->compilation()->method()->print_name();
+tty->print("@ %d ", allocator->compilation()->method()->code_size());
+tty->print("@ %d ", allocator->block_at(allocator->block_count() - 1)->last_lir_instruction_id() / 2);
+tty->print("@ %d ", allocator->block_count());
+tty->print("@ %d ", allocator->num_virtual_regs());
+tty->print("@ %d ", allocator->interval_count());
+tty->print("@ %d ", allocator->_num_calls);
+tty->print("@ %d ", allocator->num_loops());
+tty->print("@ %6.6f ", total);
+for (int i = 1; i < number_of_timers; i++) {
+tty->print("@ %4.1f ", ((timer(i)->seconds() - c) / total) * 100);
+}
+tty->cr();
+}
+}
+}
+void LinearScanTimers::print(double total_time) {
+if (TimeLinearScan) {
+// correction value: sum of dummy-timer that only measures the time that
+// is necesary to start and stop itself
+double c = timer(timer_do_nothing)->seconds();
+for (int i = 0; i < number_of_timers; i++) {
+double t = timer(i)->seconds();
+tty->print_cr("    %25s: %6.3f s (%4.1f%%)  corrected: %6.3f s (%4.1f%%)", timer_name(i), t, (t / total_time) * 100.0, t - c, (t - c) / (total_time - 2 * number_of_timers * c) * 100);
+}
+}
+}
+#endif // #ifndef PRODUCT

changeset 1	489c9b5090e2
child 1066	717c3345024f