/* * Copyright (c) 2005, 2019, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. * */ #include "precompiled.hpp" #include "c1/c1_CFGPrinter.hpp" #include "c1/c1_CodeStubs.hpp" #include "c1/c1_Compilation.hpp" #include "c1/c1_FrameMap.hpp" #include "c1/c1_IR.hpp" #include "c1/c1_LIRGenerator.hpp" #include "c1/c1_LinearScan.hpp" #include "c1/c1_ValueStack.hpp" #include "code/vmreg.inline.hpp" #include "runtime/timerTrace.hpp" #include "utilities/bitMap.inline.hpp" #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, 2, 1, 2, 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, 1, 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(NULL) , _sorted_intervals(NULL) , _needs_full_resort(false) , _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) // initialized later with correct length , _cached_blocks(*ir->linear_scan_order()) #ifdef X86 , _fpu_stack_allocator(NULL) #endif { 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 X86 } 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(); return -1; } } 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 X86 } 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(); return -1; } } // ********** 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) { #if defined(__SOFTFP__) || defined(E500V2) return i->reg_num() >= LIR_OprDesc::vreg_base; #else return i->reg_num() >= LIR_OprDesc::vreg_base && (i->type() != T_FLOAT && i->type() != T_DOUBLE); #endif // __SOFTFP__ or E500V2 } 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) { #if defined(__SOFTFP__) || defined(E500V2) return false; #else return i->reg_num() >= LIR_OprDesc::vreg_base && (i->type() == T_FLOAT || i->type() == T_DOUBLE); #endif // __SOFTFP__ or E500V2 } 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); IntervalList* new_intervals = _new_intervals_from_allocation; if (new_intervals == NULL) { new_intervals = _new_intervals_from_allocation = new IntervalList(); } new_intervals->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, num_instructions, NULL); _block_of_op = BlockBeginArray(num_instructions, num_instructions, NULL); 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.initialize(num_instructions); _has_info.initialize(num_instructions); } // ********** 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()); // iterate all blocks for (int i = 0; i < num_blocks; i++) { BlockBegin* block = block_at(i); ResourceBitMap live_gen(live_size); ResourceBitMap live_kill(live_size); 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, if (!phi->is_illegal()) { 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); local_has_fpu_registers = local_has_fpu_registers || value->type()->is_float_kind(); ); } // 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 (ResourceBitMap(live_size)); block->set_live_out (ResourceBitMap(live_size)); 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; ResourceBitMap live_out(live_set_size()); // 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. ResourceBitMap 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! ResourceBitMap 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 ResourceBitMap live_in_args(ir()->start()->live_in().size()); 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; } } #if defined(X86) || defined(S390) 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 S390_ONLY(|| true)) { // 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; } } default: break; } } 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; } } default: break; } } // We want to sometimes use logical operations on pointers, in particular in GC barriers. // Since 64bit logical operations do not current support operands on stack, we have to make sure // T_OBJECT doesn't get spilled along with T_LONG. } else if (opr_type != T_LONG LP64_ONLY(&& opr_type != T_OBJECT)) { // 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; } } default: break; } } #endif // X86 S390 // 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; } default: 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 // performed and so the temp ranges would be useless if (has_fpu_registers()) { #ifdef X86 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 X86 } if (UseSSE > 0) { int num_caller_save_xmm_regs = FrameMap::get_num_caller_save_xmms(); for (i = 0; i < num_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; ResourceBitMap live = block->live_out(); int size = (int)live.size(); for (int number = (int)live.get_next_one_offset(0, size); number < size; number = (int)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 int interval_cmp(Interval* const& l, Interval* const& r) { return l->from() - r->from(); } bool find_interval(Interval* interval, IntervalArray* intervals) { bool found; int idx = intervals->find_sorted(interval, found); if (!found) { return false; } int from = interval->from(); // The index we've found using binary search is pointing to an interval // that is defined in the same place as the interval we were looking for. // So now we have to look around that index and find exact interval. for (int i = idx; i >= 0; i--) { if (intervals->at(i) == interval) { return true; } if (intervals->at(i)->from() != from) { break; } } for (int i = idx + 1; i < intervals->length(); i++) { if (intervals->at(i) == interval) { return true; } if (intervals->at(i)->from() != from) { break; } } return false; } bool LinearScan::is_sorted(IntervalArray* intervals) { int from = -1; int null_count = 0; for (int i = 0; i < intervals->length(); i++) { Interval* it = intervals->at(i); if (it != NULL) { assert(from <= it->from(), "Intervals are unordered"); from = it->from(); } else { null_count++; } } assert(null_count == 0, "Sorted intervals should not contain nulls"); null_count = 0; for (int i = 0; i < interval_count(); i++) { Interval* interval = interval_at(i); if (interval != NULL) { assert(find_interval(interval, intervals), "Lists do not contain same intervals"); } else { null_count++; } } assert(interval_count() - null_count == intervals->length(), "Sorted list should contain the same amount of non-NULL intervals as unsorted list"); 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); if (_needs_full_resort) { // There is no known reason why this should occur but just in case... assert(false, "should never occur"); // Re-sort existing interval list because an Interval::from() has changed _sorted_intervals->sort(interval_cmp); _needs_full_resort = false; } 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, sorted_len, NULL); // 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; assert(is_sorted(_sorted_intervals), "intervals unsorted"); } void LinearScan::sort_intervals_after_allocation() { TIME_LINEAR_SCAN(timer_sort_intervals_after); if (_needs_full_resort) { // Re-sort existing interval list because an Interval::from() has changed _sorted_intervals->sort(interval_cmp); _needs_full_resort = false; } IntervalArray* old_list = _sorted_intervals; IntervalList* new_list = _new_intervals_from_allocation; int old_len = old_list->length(); int new_len = new_list == NULL ? 0 : new_list->length(); if (new_len == 0) { // no intervals have been added during allocation, so sorted list is already up to date assert(is_sorted(_sorted_intervals), "intervals unsorted"); return; } // conventional sort-algorithm for new intervals new_list->sort(interval_cmp); // merge old and new list (both already sorted) into one combined list int combined_list_len = old_len + new_len; IntervalArray* combined_list = new IntervalArray(combined_list_len, combined_list_len, NULL); 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; assert(is_sorted(_sorted_intervals), "intervals unsorted"); } 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; // collect cpu intervals create_unhandled_lists(&precolored_cpu_intervals, ¬_precolored_cpu_intervals, is_precolored_cpu_interval, is_virtual_cpu_interval); // collect fpu intervals create_unhandled_lists(&precolored_fpu_intervals, ¬_precolored_fpu_intervals, is_precolored_fpu_interval, is_virtual_fpu_interval); // this fpu interval collection cannot be moved down below with the allocation section as // the cpu_lsw.walk() changes interval positions. if (!has_fpu_registers()) { #ifdef ASSERT assert(not_precolored_fpu_intervals == Interval::end(), "missed an uncolored fpu interval"); #else if (not_precolored_fpu_intervals != Interval::end()) { BAILOUT("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 size = live_set_size(); const ResourceBitMap live_at_edge = to_block->live_in(); // visit all registers where the live_at_edge bit is set for (int r = (int)live_at_edge.get_next_one_offset(0, size); r < size; r = (int)live_at_edge.get_next_one_offset(r + 1, size)) { assert(r < num_virtual_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); ResourceBitMap block_completed(num_blocks); ResourceBitMap already_resolved(num_blocks); 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); } else { _needs_full_resort = true; } 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 = (int)block->live_in().get_next_one_offset(0, size); r < size; r = (int)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, if (!phi->is_illegal()) { 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(), 0); 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() || con->operand()->is_constant())) { // Need a mapping from constant to interval if unpinned (may have no register) or if the operand is a constant (no register). 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 = (int)block->live_in().get_next_one_offset(0, size); r < size; r = (int)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, if (!phi->is_illegal()) { 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_ADDRESS: { 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_address(assigned_reg); } case T_METADATA: { 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_metadata(assigned_reg); } #ifdef __SOFTFP__ case T_FLOAT: // fall through #endif // __SOFTFP__ 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); } #ifdef __SOFTFP__ case T_DOUBLE: // fall through #endif // __SOFTFP__ 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 _LP64 return LIR_OprFact::double_cpu(assigned_reg, assigned_reg); #else #if defined(SPARC) || defined(PPC32) return LIR_OprFact::double_cpu(assigned_regHi, assigned_reg); #else return LIR_OprFact::double_cpu(assigned_reg, assigned_regHi); #endif // SPARC #endif // LP64 } #ifndef __SOFTFP__ case T_FLOAT: { #ifdef X86 if (UseSSE >= 1) { int last_xmm_reg = pd_last_xmm_reg; #ifdef _LP64 if (UseAVX < 3) { last_xmm_reg = pd_first_xmm_reg + (pd_nof_xmm_regs_frame_map / 2) - 1; } #endif assert(assigned_reg >= pd_first_xmm_reg && assigned_reg <= 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 X86 if (UseSSE >= 2) { int last_xmm_reg = pd_last_xmm_reg; #ifdef _LP64 if (UseAVX < 3) { last_xmm_reg = pd_first_xmm_reg + (pd_nof_xmm_regs_frame_map / 2) - 1; } #endif assert(assigned_reg >= pd_first_xmm_reg && assigned_reg <= 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); #elif defined(ARM32) 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(assigned_reg - pd_first_fpu_reg, interval->assigned_regHi() - 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; } #endif // __SOFTFP__ 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 X86 // 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* 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* 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->stack()->bci() != SynchronizationEntryBCI && !info->scope()->method()->is_native()) { Bytecodes::Code code = info->scope()->method()->java_code_at_bci(info->stack()->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; default: 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); // 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 (op->is_patching() || 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); set_oop(map, 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"); set_oop(map, 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()->total_locks_size(); for (int i = 0; i < locks_count; i++) { set_oop(map, 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; // compute worst case interpreter size in case of a deoptimization _compilation->update_interpreter_frame_size(info->interpreter_frame_size()); 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 // Allocate them with new so they are never destroyed (otherwise, a // forced exit could destroy these objects while they are still in // use). ConstantOopWriteValue* LinearScan::_oop_null_scope_value = new (ResourceObj::C_HEAP, mtCompiler) ConstantOopWriteValue(NULL); ConstantIntValue* LinearScan::_int_m1_scope_value = new (ResourceObj::C_HEAP, mtCompiler) ConstantIntValue(-1); ConstantIntValue* LinearScan::_int_0_scope_value = new (ResourceObj::C_HEAP, mtCompiler) ConstantIntValue((jint)0); ConstantIntValue* LinearScan::_int_1_scope_value = new (ResourceObj::C_HEAP, mtCompiler) ConstantIntValue(1); ConstantIntValue* LinearScan::_int_2_scope_value = new (ResourceObj::C_HEAP, mtCompiler) ConstantIntValue(2); LocationValue* _illegal_value = new (ResourceObj::C_HEAP, mtCompiler) LocationValue(Location()); void LinearScan::init_compute_debug_info() { // cache for frequently used scope values // (cpu registers and stack slots) int cache_size = (LinearScan::nof_cpu_regs + frame_map()->argcount() + max_spills()) * 2; _scope_value_cache = ScopeValueArray(cache_size, cache_size, 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* 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: { #ifdef _LP64 scope_values->append(_int_0_scope_value); scope_values->append(new ConstantLongValue(c->as_jlong_bits())); #else 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())); } #endif return 2; } case T_ADDRESS: { #ifdef _LP64 scope_values->append(new ConstantLongValue(c->as_jint())); #else scope_values->append(new ConstantIntValue(c->as_jint())); #endif return 1; } default: ShouldNotReachHere(); return -1; } } int LinearScan::append_scope_value_for_operand(LIR_Opr opr, GrowableArray* 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); Location::Type int_loc_type = NOT_LP64(Location::normal) LP64_ONLY(Location::int_in_long); ScopeValue* sv = _scope_value_cache.at(cache_idx); if (sv == NULL) { Location::Type loc_type = is_oop ? Location::oop : int_loc_type; 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 : int_loc_type, frame_map()->regname(opr))))); scope_values->append(sv); return 1; #ifdef X86 } 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 X86 // 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()); #ifndef __SOFTFP__ #ifndef VM_LITTLE_ENDIAN // On S390 a (single precision) float value occupies only the high // word of the full double register. So when the double register is // stored to memory (e.g. by the RegisterSaver), then the float value // is found at offset 0. I.e. the code below is not needed on S390. #ifndef S390 if (! float_saved_as_double) { // On big endian system, we may have an issue if float registers use only // the low half of the (same) double registers. // Both the float and the double could have the same regnr but would correspond // to two different addresses once saved. // get next safely (no assertion checks) VMReg next = VMRegImpl::as_VMReg(1+rname->value()); if (next->is_reg() && (next->as_FloatRegister() == rname->as_FloatRegister())) { // the back-end does use the same numbering for the double and the float rname = next; // VMReg for the low bits, e.g. the real VMReg for the float } } #endif // !S390 #endif #endif 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()) { #ifdef _LP64 Location loc1; Location::Type loc_type = opr->type() == T_LONG ? Location::lng : Location::dbl; if (!frame_map()->locations_for_slot(opr->double_stack_ix(), loc_type, &loc1, NULL)) { bailout("too large frame"); } // Does this reverse on x86 vs. sparc? first = new LocationValue(loc1); second = _int_0_scope_value; #else 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); #endif // _LP64 } 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 //_LP64 #ifdef X86 } 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(); # ifdef _LP64 first = new LocationValue(Location::new_reg_loc(Location::dbl, rname_first)); second = _int_0_scope_value; # else 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 #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 X86, // 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 X86 // 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_regnrLo is used)"); #endif #ifdef SPARC assert(opr->fpu_regnrLo() == opr->fpu_regnrHi() + 1, "assumed in calculation (only fpu_regnrHi is used)"); #endif #ifdef ARM32 assert(opr->fpu_regnrHi() == opr->fpu_regnrLo() + 1, "assumed in calculation (only fpu_regnrLo is used)"); #endif #ifdef PPC32 assert(opr->fpu_regnrLo() == opr->fpu_regnrHi(), "assumed in calculation (only fpu_regnrHi is used)"); #endif #ifdef VM_LITTLE_ENDIAN VMReg rname_first = frame_map()->fpu_regname(opr->fpu_regnrLo()); #else VMReg rname_first = frame_map()->fpu_regname(opr->fpu_regnrHi()); #endif #ifdef _LP64 first = new LocationValue(Location::new_reg_loc(Location::dbl, rname_first)); second = _int_0_scope_value; #else 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 { 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* 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) { IRScopeDebugInfo* caller_debug_info = NULL; ValueStack* caller_state = cur_state->caller_state(); if (caller_state != NULL) { // process recursively to compute outermost scope first caller_debug_info = compute_debug_info_for_scope(op_id, cur_scope->caller(), caller_state, innermost_state); } // 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* locals = NULL; GrowableArray* expressions = NULL; GrowableArray* monitors = NULL; // describe local variable values int nof_locals = cur_state->locals_size(); if (nof_locals > 0) { locals = new GrowableArray(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"); } else if (cur_scope->method()->max_locals() > 0) { assert(cur_state->kind() == ValueStack::EmptyExceptionState, "should be"); nof_locals = cur_scope->method()->max_locals(); locals = new GrowableArray(nof_locals); for(int i = 0; i < nof_locals; i++) { locals->append(_illegal_value); } } // describe expression stack int nof_stack = cur_state->stack_size(); if (nof_stack > 0) { expressions = new GrowableArray(nof_stack); int pos = 0; while (pos < nof_stack) { Value expression = cur_state->stack_at_inc(pos); append_scope_value(op_id, expression, expressions); assert(expressions->length() == pos, "must match"); } assert(expressions->length() == cur_state->stack_size(), "wrong number of stack entries"); } // describe monitors int nof_locks = cur_state->locks_size(); if (nof_locks > 0) { int lock_offset = cur_state->caller_state() != NULL ? cur_state->caller_state()->total_locks_size() : 0; monitors = new GrowableArray(nof_locks); for (int i = 0; i < nof_locks; i++) { monitors->append(location_for_monitor_index(lock_offset + i)); } } return new IRScopeDebugInfo(cur_scope, cur_state->bci(), locals, expressions, monitors, caller_debug_info); } void LinearScan::compute_debug_info(CodeEmitInfo* info, int op_id) { 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?"); DEBUG_ONLY(check_stack_depth(info, innermost_state->stack_size())); 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); } 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))); } } 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 // 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; } } } 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->trunc_to(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:")); sort_intervals_after_allocation(); DEBUG_ONLY(verify()); 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; } // 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 (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 || (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 ((r1 == r2 || r1 == r2Hi || (r1Hi != any_reg && (r1Hi == r2 || r1Hi == r2Hi))) && i1->intersects(i2)) { 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() { Interval* fixed_intervals; Interval* other_intervals; create_unhandled_lists(&fixed_intervals, &other_intervals, is_precolored_cpu_interval, NULL); // to ensure a walking until the last instruction id, add a dummy interval // with a high operation id other_intervals = new Interval(any_reg); other_intervals->add_range(max_jint - 2, max_jint - 1); IntervalWalker* iw = new IntervalWalker(this, fixed_intervals, other_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); if (visitor.info_count() > 0) { iw->walk_before(op->id()); bool check_live = true; if (op->code() == lir_move) { LIR_Op1* move = (LIR_Op1*)op; check_live = (move->patch_code() == lir_patch_none); } LIR_OpBranch* branch = op->as_OpBranch(); if (branch != NULL && branch->stub() != NULL && branch->stub()->is_exception_throw_stub()) { // Don't bother checking the stub in this case since the // exception stub will never return to normal control flow. check_live = false; } // Make sure none of the fixed registers is live across an // oopmap since we can't handle that correctly. if (check_live) { for (Interval* interval = iw->active_first(fixedKind); interval != Interval::end(); interval = interval->next()) { if (interval->current_to() > op->id() + 1) { // This interval is live out of this op so make sure // that this interval represents some value that's // referenced by this op either as an input or output. bool ok = false; 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()) { if (interval_at(reg_num(opr)) == interval) { ok = true; break; } int hi = reg_numHi(opr); if (hi != -1 && interval_at(hi) == interval) { ok = true; break; } } } } assert(ok, "fixed intervals should never be live across an oopmap point"); } } } } // 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); ResourceBitMap live_at_edge = block->live_in(); // visit all registers where the live_at_edge bit is set for (int r = (int)live_at_edge.get_next_one_offset(0, size); r < size; r = (int)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(), 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 int input_state_len = state_size(); IntervalList* input_state = new IntervalList(input_state_len, input_state_len, 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->appendAll(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 X86 int num_caller_save_xmm_regs = FrameMap::get_num_caller_save_xmms(); for (j = 0; j < num_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"); } } ResourceBitMap used_regs(LinearScan::nof_regs + allocator()->frame_map()->argcount() + allocator()->max_spills()); 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 = get_virtual_register(from_interval); LIR_Opr to_opr = get_virtual_register(to_interval); 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 = get_virtual_register(to_interval); _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())); } LIR_Opr MoveResolver::get_virtual_register(Interval* interval) { // Add a little fudge factor for the bailout since the bailout is only checked periodically. This allows us to hand out // a few extra registers before we really run out which helps to avoid to trip over assertions. int reg_num = interval->reg_num(); if (reg_num + 20 >= LIR_OprDesc::vreg_max) { _allocator->bailout("out of virtual registers in linear scan"); if (reg_num + 2 >= LIR_OprDesc::vreg_max) { // Wrap it around and continue until bailout really happens to avoid hitting assertions. reg_num = LIR_OprDesc::vreg_base; } } LIR_Opr vreg = LIR_OprFact::virtual_register(reg_num, interval->type()); assert(vreg != LIR_OprFact::illegal(), "ran out of virtual registers"); return vreg; } 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 guarantee(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(Arena* arena) { _end = new (arena) 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(Arena* arena) { Range::initialize(arena); _end = new (arena) 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(NULL), _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 != NULL && _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 != NULL && _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 == NULL || _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; assert(parent->_split_children != NULL, "no split children available"); 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; } // 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 == NULL) { assert(is_split_parent(), "list must be initialized at first split"); parent->_split_children = new 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.trunc_to(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; } // Check if there is an intersection with any of the split children of 'interval' bool Interval::intersects_any_children_of(Interval* interval) const { if (interval->_split_children != NULL) { for (int i = 0; i < interval->_split_children->length(); i++) { if (intersects(interval->_split_children->at(i))) { return true; } } } 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 #ifdef X86 int last_xmm_reg = pd_last_xmm_reg; #ifdef _LP64 if (UseAVX < 3) { last_xmm_reg = pd_first_xmm_reg + (pd_nof_xmm_regs_frame_map / 2) - 1; } #endif #endif 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 X86 } else if (assigned_reg() >= pd_first_xmm_reg && assigned_reg() <= 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 && (LinearScan::num_physical_regs(type()) == 1 || assigned_regHi() != -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 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::spill_exclude_active_fixed() { Interval* list = active_first(fixedKind); while (list != Interval::end()) { exclude_from_use(list); 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); 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; int 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 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 || _use_pos[i] > _use_pos[max_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, 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 (max_reg != any_reg && (_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->find(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(); 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, &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, 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, 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 X86 // 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 = FrameMap::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"); assert(!cur->intersects(register_hint), "cur should not intersect register_hint"); if (cur->intersects_any_children_of(register_hint)) { // Bail out if cur intersects any split children of register_hint, which have the same spill slot as their parent. An overlap of two intervals with // the same spill slot could result in a situation where both intervals are spilled at the same time to the same stack location which is not correct. return; } // 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.find(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->trunc_to(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->trunc_to(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->stub() == NULL) { LIR_Op2* prev_cmp = NULL; // There might be a cmove inserted for profiling which depends on the same // compare. If we change the condition of the respective compare, we have // to take care of this cmove as well. LIR_Op2* prev_cmove = NULL; for(int j = instructions->length() - 3; j >= 0 && prev_cmp == NULL; j--) { prev_op = instructions->at(j); // check for the cmove if (prev_op->code() == lir_cmove) { assert(prev_op->as_Op2() != NULL, "cmove must be of type LIR_Op2"); prev_cmove = (LIR_Op2*)prev_op; assert(prev_branch->cond() == prev_cmove->condition(), "should be the same"); } if (prev_op->code() == lir_cmp) { assert(prev_op->as_Op2() != NULL, "branch must be of type LIR_Op2"); prev_cmp = (LIR_Op2*)prev_op; assert(prev_branch->cond() == prev_cmp->condition(), "should be the same"); } } // Guarantee because it is dereferenced below. guarantee(prev_cmp != NULL, "should have found comp instruction for branch"); 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(); prev_cmp->set_condition(prev_branch->cond()); instructions->trunc_to(instructions->length() - 1); // if we do change the condition, we have to change the cmove as well if (prev_cmove != NULL) { prev_cmove->set_condition(prev_branch->cond()); LIR_Opr t = prev_cmove->in_opr1(); prev_cmove->set_in_opr1(prev_cmove->in_opr2()); prev_cmove->set_in_opr2(t); } } } } } } } } DEBUG_ONLY(verify(code)); } void ControlFlowOptimizer::delete_jumps_to_return(BlockList* code) { #ifdef ASSERT ResourceBitMap return_converted(BlockBegin::number_of_blocks()); #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->find(op_branch->block()) != -1, "branch target not valid"); assert(op_branch->ublock() == NULL || code->find(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->find(sux) != -1, "successor not valid"); } for (j = 0; j < block->number_of_preds() - 1; j++) { BlockBegin* pred = block->pred_at(j); assert(code->find(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]); LinearScanStatistic::Counter cntr = base_counter(i); if (cntr != invalid_counter) { tty->print(" (%5.1f%%) ", _counters_sum[i] * 100.0 / _counters_sum[cntr]); } 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_abs: case lir_log10: 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