| /* |
| * Copyright (c) 2015, 2015, 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. |
| */ |
| package org.graalvm.compiler.lir.alloc.lsra; |
| |
| import static org.graalvm.compiler.core.common.GraalOptions.DetailedAsserts; |
| import static org.graalvm.compiler.lir.LIRValueUtil.isStackSlotValue; |
| import static org.graalvm.compiler.lir.LIRValueUtil.isVariable; |
| import static org.graalvm.compiler.lir.phases.LIRPhase.Options.LIROptimization; |
| import static jdk.vm.ci.code.ValueUtil.isRegister; |
| |
| import java.util.List; |
| |
| import org.graalvm.compiler.core.common.cfg.AbstractBlockBase; |
| import org.graalvm.compiler.debug.Debug; |
| import org.graalvm.compiler.debug.Indent; |
| import org.graalvm.compiler.lir.LIRInsertionBuffer; |
| import org.graalvm.compiler.lir.LIRInstruction; |
| import org.graalvm.compiler.lir.StandardOp.LoadConstantOp; |
| import org.graalvm.compiler.lir.StandardOp.MoveOp; |
| import org.graalvm.compiler.lir.StandardOp.ValueMoveOp; |
| import org.graalvm.compiler.lir.alloc.lsra.Interval.SpillState; |
| import org.graalvm.compiler.lir.alloc.lsra.LinearScan.IntervalPredicate; |
| import org.graalvm.compiler.lir.gen.LIRGenerationResult; |
| import org.graalvm.compiler.lir.phases.AllocationPhase; |
| import org.graalvm.compiler.options.NestedBooleanOptionValue; |
| import org.graalvm.compiler.options.Option; |
| import org.graalvm.compiler.options.OptionType; |
| import org.graalvm.compiler.options.OptionValue; |
| |
| import jdk.vm.ci.code.TargetDescription; |
| import jdk.vm.ci.meta.AllocatableValue; |
| |
| public class LinearScanEliminateSpillMovePhase extends AllocationPhase { |
| |
| public static class Options { |
| // @formatter:off |
| @Option(help = "Enable spill move elimination.", type = OptionType.Debug) |
| public static final OptionValue<Boolean> LIROptLSRAEliminateSpillMoves = new NestedBooleanOptionValue(LIROptimization, true); |
| // @formatter:on |
| } |
| |
| private static final IntervalPredicate mustStoreAtDefinition = new LinearScan.IntervalPredicate() { |
| |
| @Override |
| public boolean apply(Interval i) { |
| return i.isSplitParent() && i.spillState() == SpillState.StoreAtDefinition; |
| } |
| }; |
| |
| protected final LinearScan allocator; |
| |
| protected LinearScanEliminateSpillMovePhase(LinearScan allocator) { |
| this.allocator = allocator; |
| } |
| |
| @Override |
| protected void run(TargetDescription target, LIRGenerationResult lirGenRes, AllocationContext context) { |
| eliminateSpillMoves(); |
| } |
| |
| /** |
| * @return the index of the first instruction that is of interest for |
| * {@link #eliminateSpillMoves()} |
| */ |
| protected int firstInstructionOfInterest() { |
| // skip the first because it is always a label |
| return 1; |
| } |
| |
| // called once before assignment of register numbers |
| @SuppressWarnings("try") |
| void eliminateSpillMoves() { |
| try (Indent indent = Debug.logAndIndent("Eliminating unnecessary spill moves")) { |
| |
| /* |
| * collect all intervals that must be stored after their definition. The list is sorted |
| * by Interval.spillDefinitionPos. |
| */ |
| Interval interval; |
| interval = allocator.createUnhandledLists(mustStoreAtDefinition, null).first; |
| if (DetailedAsserts.getValue()) { |
| checkIntervals(interval); |
| } |
| |
| LIRInsertionBuffer insertionBuffer = new LIRInsertionBuffer(); |
| for (AbstractBlockBase<?> block : allocator.sortedBlocks()) { |
| try (Indent indent1 = Debug.logAndIndent("Handle %s", block)) { |
| List<LIRInstruction> instructions = allocator.getLIR().getLIRforBlock(block); |
| int numInst = instructions.size(); |
| |
| // iterate all instructions of the block. |
| for (int j = firstInstructionOfInterest(); j < numInst; j++) { |
| LIRInstruction op = instructions.get(j); |
| int opId = op.id(); |
| |
| if (opId == -1) { |
| MoveOp move = (MoveOp) op; |
| /* |
| * 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. |
| */ |
| if (Options.LIROptLSRAEliminateSpillMoves.getValue() && canEliminateSpillMove(block, move)) { |
| /* |
| * Move target is a stack slot that is always correct, so eliminate |
| * instruction. |
| */ |
| if (Debug.isLogEnabled()) { |
| if (move instanceof ValueMoveOp) { |
| ValueMoveOp vmove = (ValueMoveOp) move; |
| Debug.log("eliminating move from interval %d (%s) to %d (%s) in block %s", allocator.operandNumber(vmove.getInput()), vmove.getInput(), |
| allocator.operandNumber(vmove.getResult()), vmove.getResult(), block); |
| } else { |
| LoadConstantOp load = (LoadConstantOp) move; |
| Debug.log("eliminating constant load from %s to %d (%s) in block %s", load.getConstant(), allocator.operandNumber(load.getResult()), load.getResult(), block); |
| } |
| } |
| |
| // null-instructions are deleted by assignRegNum |
| instructions.set(j, null); |
| } |
| |
| } else { |
| /* |
| * Insert move from register to stack just after the beginning of the |
| * interval. |
| */ |
| assert interval == Interval.EndMarker || interval.spillDefinitionPos() >= opId : "invalid order"; |
| assert interval == Interval.EndMarker || (interval.isSplitParent() && interval.spillState() == SpillState.StoreAtDefinition) : "invalid interval"; |
| |
| while (interval != Interval.EndMarker && interval.spillDefinitionPos() == opId) { |
| if (!interval.canMaterialize()) { |
| if (!insertionBuffer.initialized()) { |
| /* |
| * prepare insertion buffer (appended when all instructions |
| * in the block are processed) |
| */ |
| insertionBuffer.init(instructions); |
| } |
| |
| AllocatableValue fromLocation = interval.location(); |
| AllocatableValue toLocation = LinearScan.canonicalSpillOpr(interval); |
| if (!fromLocation.equals(toLocation)) { |
| |
| assert isRegister(fromLocation) : "from operand must be a register but is: " + fromLocation + " toLocation=" + toLocation + " spillState=" + |
| interval.spillState(); |
| assert isStackSlotValue(toLocation) : "to operand must be a stack slot"; |
| |
| LIRInstruction move = allocator.getSpillMoveFactory().createMove(toLocation, fromLocation); |
| insertionBuffer.append(j + 1, move); |
| |
| if (Debug.isLogEnabled()) { |
| Debug.log("inserting move after definition of interval %d to stack slot %s at opId %d", interval.operandNumber, interval.spillSlot(), opId); |
| } |
| } |
| } |
| interval = interval.next; |
| } |
| } |
| } // end of instruction iteration |
| |
| if (insertionBuffer.initialized()) { |
| insertionBuffer.finish(); |
| } |
| } |
| } // end of block iteration |
| |
| assert interval == Interval.EndMarker : "missed an interval"; |
| } |
| } |
| |
| /** |
| * @param block The block {@code move} is located in. |
| * @param move Spill move. |
| */ |
| protected boolean canEliminateSpillMove(AbstractBlockBase<?> block, MoveOp move) { |
| assert isVariable(move.getResult()) : "LinearScan inserts only moves to variables: " + move; |
| |
| Interval curInterval = allocator.intervalFor(move.getResult()); |
| |
| if (!isRegister(curInterval.location()) && curInterval.alwaysInMemory()) { |
| assert isStackSlotValue(curInterval.location()) : "Not a stack slot: " + curInterval.location(); |
| return true; |
| } |
| return false; |
| } |
| |
| private static void checkIntervals(Interval interval) { |
| Interval prev = null; |
| Interval temp = interval; |
| while (temp != Interval.EndMarker) { |
| assert temp.spillDefinitionPos() > 0 : "invalid spill definition pos"; |
| if (prev != null) { |
| assert temp.from() >= prev.from() : "intervals not sorted"; |
| assert temp.spillDefinitionPos() >= prev.spillDefinitionPos() : "when intervals are sorted by from : then they must also be sorted by spillDefinitionPos"; |
| } |
| |
| assert temp.spillSlot() != null || temp.canMaterialize() : "interval has no spill slot assigned"; |
| assert temp.spillDefinitionPos() >= temp.from() : "invalid order"; |
| assert temp.spillDefinitionPos() <= temp.from() + 2 : "only intervals defined once at their start-pos can be optimized"; |
| |
| if (Debug.isLogEnabled()) { |
| Debug.log("interval %d (from %d to %d) must be stored at %d", temp.operandNumber, temp.from(), temp.to(), temp.spillDefinitionPos()); |
| } |
| |
| prev = temp; |
| temp = temp.next; |
| } |
| } |
| |
| } |
