Mercurial > hg > graal-compiler
diff src/share/vm/c1/c1_LinearScan.cpp @ 0:a61af66fc99e jdk7-b24
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author | duke |
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date | Sat, 01 Dec 2007 00:00:00 +0000 |
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children | dc7f315e41f7 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/share/vm/c1/c1_LinearScan.cpp Sat Dec 01 00:00:00 2007 +0000 @@ -0,0 +1,6530 @@ +/* + * 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, ¬_precolored_cpu_intervals, is_precolored_cpu_interval, is_virtual_cpu_interval); + if (has_fpu_registers()) { + create_unhandled_lists(&precolored_fpu_intervals, ¬_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, ¬_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