/* * Copyright (c) 2015, 2016, 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.trace.lsra; import static org.graalvm.compiler.core.common.GraalOptions.DetailedAsserts; import static org.graalvm.compiler.lir.LIRValueUtil.asConstant; import static org.graalvm.compiler.lir.LIRValueUtil.isConstantValue; import static org.graalvm.compiler.lir.LIRValueUtil.isStackSlotValue; import static org.graalvm.compiler.lir.LIRValueUtil.isVirtualStackSlot; import static jdk.vm.ci.code.ValueUtil.isRegister; import java.util.List; import org.graalvm.compiler.core.common.alloc.Trace; import org.graalvm.compiler.core.common.alloc.TraceBuilderResult; import org.graalvm.compiler.core.common.cfg.AbstractBlockBase; import org.graalvm.compiler.debug.Debug; import org.graalvm.compiler.debug.DebugCounter; import org.graalvm.compiler.debug.Indent; import org.graalvm.compiler.lir.LIRInstruction; import org.graalvm.compiler.lir.StandardOp; import org.graalvm.compiler.lir.alloc.trace.lsra.TraceLinearScanPhase.TraceLinearScan; import org.graalvm.compiler.lir.gen.LIRGenerationResult; import org.graalvm.compiler.lir.ssa.SSAUtil.PhiValueVisitor; import org.graalvm.compiler.lir.ssi.SSIUtil; import jdk.vm.ci.code.TargetDescription; import jdk.vm.ci.meta.Value; /** * Phase 6: resolve data flow * * Insert moves at edges between blocks if intervals have been split. */ final class TraceLinearScanResolveDataFlowPhase extends TraceLinearScanAllocationPhase { @Override protected void run(TargetDescription target, LIRGenerationResult lirGenRes, Trace trace, TraceLinearScanAllocationContext context) { TraceBuilderResult traceBuilderResult = context.resultTraces; TraceLinearScan allocator = context.allocator; new Resolver(allocator, traceBuilderResult).resolveDataFlow(trace, allocator.sortedBlocks()); } private static final class Resolver { private final TraceLinearScan allocator; private final TraceBuilderResult traceBuilderResult; private Resolver(TraceLinearScan allocator, TraceBuilderResult traceBuilderResult) { this.allocator = allocator; this.traceBuilderResult = traceBuilderResult; } private void resolveFindInsertPos(AbstractBlockBase fromBlock, AbstractBlockBase toBlock, TraceLocalMoveResolver moveResolver) { if (fromBlock.getSuccessorCount() <= 1) { if (Debug.isLogEnabled()) { Debug.log("inserting moves at end of fromBlock B%d", fromBlock.getId()); } List instructions = allocator.getLIR().getLIRforBlock(fromBlock); LIRInstruction instr = instructions.get(instructions.size() - 1); if (instr instanceof StandardOp.JumpOp) { // insert moves before branch moveResolver.setInsertPosition(instructions, instructions.size() - 1); } else { moveResolver.setInsertPosition(instructions, instructions.size()); } } else { if (Debug.isLogEnabled()) { Debug.log("inserting moves at beginning of toBlock B%d", toBlock.getId()); } if (DetailedAsserts.getValue()) { assert allocator.getLIR().getLIRforBlock(fromBlock).get(0) instanceof StandardOp.LabelOp : "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 (AbstractBlockBase predecessor : toBlock.getPredecessors()) { assert fromBlock == predecessor : "all critical edges must be broken"; } } moveResolver.setInsertPosition(allocator.getLIR().getLIRforBlock(toBlock), 1); } } /** * Inserts necessary moves (spilling or reloading) at edges between blocks for intervals * that have been split. */ @SuppressWarnings("try") private void resolveDataFlow(Trace currentTrace, AbstractBlockBase[] blocks) { if (blocks.length < 2) { // no resolution necessary return; } try (Indent indent = Debug.logAndIndent("resolve data flow")) { TraceLocalMoveResolver moveResolver = allocator.createMoveResolver(); AbstractBlockBase toBlock = null; for (int i = 0; i < blocks.length - 1; i++) { AbstractBlockBase fromBlock = blocks[i]; toBlock = blocks[i + 1]; assert containedInTrace(currentTrace, fromBlock) : "Not in Trace: " + fromBlock; assert containedInTrace(currentTrace, toBlock) : "Not in Trace: " + toBlock; resolveCollectMappings(fromBlock, toBlock, moveResolver); } assert blocks[blocks.length - 1].equals(toBlock); if (toBlock.isLoopEnd()) { assert toBlock.getSuccessorCount() == 1; AbstractBlockBase loopHeader = toBlock.getSuccessors()[0]; if (containedInTrace(currentTrace, loopHeader)) { resolveCollectMappings(toBlock, loopHeader, moveResolver); } } } } @SuppressWarnings("try") private void resolveCollectMappings(AbstractBlockBase fromBlock, AbstractBlockBase toBlock, TraceLocalMoveResolver moveResolver) { try (Indent indent0 = Debug.logAndIndent("Edge %s -> %s", fromBlock, toBlock)) { // collect all intervals that have been split between // fromBlock and toBlock SSIUtil.forEachValuePair(allocator.getLIR(), toBlock, fromBlock, new MappingCollector(moveResolver, toBlock, fromBlock)); if (moveResolver.hasMappings()) { resolveFindInsertPos(fromBlock, toBlock, moveResolver); moveResolver.resolveAndAppendMoves(); } } } private boolean containedInTrace(Trace currentTrace, AbstractBlockBase block) { return currentTrace.getId() == traceBuilderResult.getTraceForBlock(block).getId(); } private static final DebugCounter numSSIResolutionMoves = Debug.counter("SSI LSRA[numSSIResolutionMoves]"); private static final DebugCounter numStackToStackMoves = Debug.counter("SSI LSRA[numStackToStackMoves]"); private class MappingCollector implements PhiValueVisitor { final TraceLocalMoveResolver moveResolver; final int toId; final int fromId; MappingCollector(TraceLocalMoveResolver moveResolver, AbstractBlockBase toBlock, AbstractBlockBase fromBlock) { this.moveResolver = moveResolver; toId = allocator.getFirstLirInstructionId(toBlock); fromId = allocator.getLastLirInstructionId(fromBlock); assert fromId >= 0; } @Override public void visit(Value phiIn, Value phiOut) { assert !isRegister(phiOut) : "Out is a register: " + phiOut; assert !isRegister(phiIn) : "In is a register: " + phiIn; if (Value.ILLEGAL.equals(phiIn)) { // The value not needed in this branch. return; } if (isVirtualStackSlot(phiIn) && isVirtualStackSlot(phiOut) && phiIn.equals(phiOut)) { // no need to handle virtual stack slots return; } TraceInterval toInterval = allocator.splitChildAtOpId(allocator.intervalFor(phiIn), toId, LIRInstruction.OperandMode.DEF); if (isConstantValue(phiOut)) { numSSIResolutionMoves.increment(); moveResolver.addMapping(asConstant(phiOut), toInterval); } else { TraceInterval fromInterval = allocator.splitChildAtOpId(allocator.intervalFor(phiOut), fromId, LIRInstruction.OperandMode.DEF); if (fromInterval != toInterval) { numSSIResolutionMoves.increment(); if (!(isStackSlotValue(toInterval.location()) && isStackSlotValue(fromInterval.location()))) { moveResolver.addMapping(fromInterval, toInterval); } else { numStackToStackMoves.increment(); moveResolver.addMapping(fromInterval, toInterval); } } } } } } }