/* * Copyright (c) 2014, 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.stackslotalloc; import static org.graalvm.compiler.lir.LIRValueUtil.asVirtualStackSlot; import static org.graalvm.compiler.lir.LIRValueUtil.isVirtualStackSlot; import static org.graalvm.compiler.lir.phases.LIRPhase.Options.LIROptimization; import java.util.ArrayDeque; import java.util.Arrays; import java.util.Deque; import java.util.EnumMap; import java.util.EnumSet; import java.util.List; import java.util.PriorityQueue; import java.util.Set; import org.graalvm.compiler.core.common.cfg.AbstractBlockBase; import org.graalvm.compiler.debug.Debug; import org.graalvm.compiler.debug.Debug.Scope; import org.graalvm.compiler.debug.DebugCloseable; import org.graalvm.compiler.debug.DebugTimer; import org.graalvm.compiler.debug.Indent; import org.graalvm.compiler.lir.LIR; import org.graalvm.compiler.lir.LIRInstruction; import org.graalvm.compiler.lir.LIRInstruction.OperandFlag; import org.graalvm.compiler.lir.LIRInstruction.OperandMode; import org.graalvm.compiler.lir.ValueProcedure; import org.graalvm.compiler.lir.VirtualStackSlot; import org.graalvm.compiler.lir.framemap.FrameMapBuilderTool; import org.graalvm.compiler.lir.framemap.SimpleVirtualStackSlot; import org.graalvm.compiler.lir.framemap.VirtualStackSlotRange; 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 jdk.vm.ci.code.StackSlot; import jdk.vm.ci.code.TargetDescription; import jdk.vm.ci.meta.Value; import jdk.vm.ci.meta.ValueKind; /** * Linear Scan {@link StackSlotAllocatorUtil stack slot allocator}. *

* Remark: The analysis works under the assumption that a stack slot is no longer live after * its last usage. If an {@link LIRInstruction instruction} transfers the raw address of the stack * slot to another location, e.g. a registers, and this location is referenced later on, the * {@link org.graalvm.compiler.lir.LIRInstruction.Use usage} of the stack slot must be marked with * the {@link OperandFlag#UNINITIALIZED}. Otherwise the stack slot might be reused and its content * destroyed. */ public final class LSStackSlotAllocator extends AllocationPhase { public static class Options { // @formatter:off @Option(help = "Use linear scan stack slot allocation.", type = OptionType.Debug) public static final NestedBooleanOptionValue LIROptLSStackSlotAllocator = new NestedBooleanOptionValue(LIROptimization, true); // @formatter:on } private static final DebugTimer MainTimer = Debug.timer("LSStackSlotAllocator"); private static final DebugTimer NumInstTimer = Debug.timer("LSStackSlotAllocator[NumberInstruction]"); private static final DebugTimer BuildIntervalsTimer = Debug.timer("LSStackSlotAllocator[BuildIntervals]"); private static final DebugTimer VerifyIntervalsTimer = Debug.timer("LSStackSlotAllocator[VerifyIntervals]"); private static final DebugTimer AllocateSlotsTimer = Debug.timer("LSStackSlotAllocator[AllocateSlots]"); private static final DebugTimer AssignSlotsTimer = Debug.timer("LSStackSlotAllocator[AssignSlots]"); @Override protected void run(TargetDescription target, LIRGenerationResult lirGenRes, AllocationContext context) { allocateStackSlots((FrameMapBuilderTool) lirGenRes.getFrameMapBuilder(), lirGenRes); lirGenRes.buildFrameMap(); } @SuppressWarnings("try") public static void allocateStackSlots(FrameMapBuilderTool builder, LIRGenerationResult res) { if (builder.getNumberOfStackSlots() > 0) { try (DebugCloseable t = MainTimer.start()) { new Allocator(res.getLIR(), builder).allocate(); } } } private static final class Allocator { private final LIR lir; private final FrameMapBuilderTool frameMapBuilder; private final StackInterval[] stackSlotMap; private final PriorityQueue unhandled; private final PriorityQueue active; private final AbstractBlockBase[] sortedBlocks; private final int maxOpId; @SuppressWarnings("try") private Allocator(LIR lir, FrameMapBuilderTool frameMapBuilder) { this.lir = lir; this.frameMapBuilder = frameMapBuilder; this.stackSlotMap = new StackInterval[frameMapBuilder.getNumberOfStackSlots()]; this.sortedBlocks = lir.getControlFlowGraph().getBlocks(); // insert by from this.unhandled = new PriorityQueue<>((a, b) -> a.from() - b.from()); // insert by to this.active = new PriorityQueue<>((a, b) -> a.to() - b.to()); try (DebugCloseable t = NumInstTimer.start()) { // step 1: number instructions this.maxOpId = numberInstructions(lir, sortedBlocks); } } @SuppressWarnings("try") private void allocate() { Debug.dump(Debug.INFO_LOG_LEVEL, lir, "After StackSlot numbering"); long currentFrameSize = StackSlotAllocatorUtil.allocatedFramesize.isEnabled() ? frameMapBuilder.getFrameMap().currentFrameSize() : 0; Set usePos; // step 2: build intervals try (Scope s = Debug.scope("StackSlotAllocationBuildIntervals"); Indent indent = Debug.logAndIndent("BuildIntervals"); DebugCloseable t = BuildIntervalsTimer.start()) { usePos = buildIntervals(); } // step 3: verify intervals if (Debug.isEnabled()) { try (DebugCloseable t = VerifyIntervalsTimer.start()) { assert verifyIntervals(); } } if (Debug.isDumpEnabled(Debug.INFO_LOG_LEVEL)) { dumpIntervals("Before stack slot allocation"); } // step 4: allocate stack slots try (DebugCloseable t = AllocateSlotsTimer.start()) { allocateStackSlots(); } if (Debug.isDumpEnabled(Debug.INFO_LOG_LEVEL)) { dumpIntervals("After stack slot allocation"); } // step 5: assign stack slots try (DebugCloseable t = AssignSlotsTimer.start()) { assignStackSlots(usePos); } Debug.dump(Debug.INFO_LOG_LEVEL, lir, "After StackSlot assignment"); if (StackSlotAllocatorUtil.allocatedFramesize.isEnabled()) { StackSlotAllocatorUtil.allocatedFramesize.add(frameMapBuilder.getFrameMap().currentFrameSize() - currentFrameSize); } } // ==================== // step 1: number instructions // ==================== /** * Numbers all instructions in all blocks. * * @return The id of the last operation. */ private static int numberInstructions(LIR lir, AbstractBlockBase[] sortedBlocks) { int opId = 0; int index = 0; for (AbstractBlockBase block : sortedBlocks) { List instructions = lir.getLIRforBlock(block); int numInst = instructions.size(); for (int j = 0; j < numInst; j++) { LIRInstruction op = instructions.get(j); op.setId(opId); index++; opId += 2; // numbering of lirOps by two } } assert (index << 1) == opId : "must match: " + (index << 1); return opId - 2; } // ==================== // step 2: build intervals // ==================== private Set buildIntervals() { return new FixPointIntervalBuilder(lir, stackSlotMap, maxOpId()).build(); } // ==================== // step 3: verify intervals // ==================== private boolean verifyIntervals() { for (StackInterval interval : stackSlotMap) { if (interval != null) { assert interval.verify(maxOpId()); } } return true; } // ==================== // step 4: allocate stack slots // ==================== @SuppressWarnings("try") private void allocateStackSlots() { // create unhandled lists for (StackInterval interval : stackSlotMap) { if (interval != null) { unhandled.add(interval); } } for (StackInterval current = activateNext(); current != null; current = activateNext()) { try (Indent indent = Debug.logAndIndent("allocate %s", current)) { allocateSlot(current); } } } private void allocateSlot(StackInterval current) { VirtualStackSlot virtualSlot = current.getOperand(); final StackSlot location; if (virtualSlot instanceof VirtualStackSlotRange) { // No reuse of ranges (yet). VirtualStackSlotRange slotRange = (VirtualStackSlotRange) virtualSlot; location = frameMapBuilder.getFrameMap().allocateStackSlots(slotRange.getSlots(), slotRange.getObjects()); StackSlotAllocatorUtil.virtualFramesize.add(frameMapBuilder.getFrameMap().spillSlotRangeSize(slotRange.getSlots())); StackSlotAllocatorUtil.allocatedSlots.increment(); } else { assert virtualSlot instanceof SimpleVirtualStackSlot : "Unexpected VirtualStackSlot type: " + virtualSlot; StackSlot slot = findFreeSlot((SimpleVirtualStackSlot) virtualSlot); if (slot != null) { /* * Free stack slot available. Note that we create a new one because the kind * might not match. */ location = StackSlot.get(current.kind(), slot.getRawOffset(), slot.getRawAddFrameSize()); StackSlotAllocatorUtil.reusedSlots.increment(); Debug.log(Debug.BASIC_LOG_LEVEL, "Reuse stack slot %s (reallocated from %s) for virtual stack slot %s", location, slot, virtualSlot); } else { // Allocate new stack slot. location = frameMapBuilder.getFrameMap().allocateSpillSlot(virtualSlot.getValueKind()); StackSlotAllocatorUtil.virtualFramesize.add(frameMapBuilder.getFrameMap().spillSlotSize(virtualSlot.getValueKind())); StackSlotAllocatorUtil.allocatedSlots.increment(); Debug.log(Debug.BASIC_LOG_LEVEL, "New stack slot %s for virtual stack slot %s", location, virtualSlot); } } Debug.log("Allocate location %s for interval %s", location, current); current.setLocation(location); } private enum SlotSize { Size1, Size2, Size4, Size8, Illegal; } private SlotSize forKind(ValueKind kind) { switch (frameMapBuilder.getFrameMap().spillSlotSize(kind)) { case 1: return SlotSize.Size1; case 2: return SlotSize.Size2; case 4: return SlotSize.Size4; case 8: return SlotSize.Size8; default: return SlotSize.Illegal; } } private EnumMap> freeSlots; /** * @return The list of free stack slots for {@code size} or {@code null} if there is none. */ private Deque getOrNullFreeSlots(SlotSize size) { if (freeSlots == null) { return null; } return freeSlots.get(size); } /** * @return the list of free stack slots for {@code size}. If there is none a list is * created. */ private Deque getOrInitFreeSlots(SlotSize size) { assert size != SlotSize.Illegal; Deque freeList; if (freeSlots != null) { freeList = freeSlots.get(size); } else { freeSlots = new EnumMap<>(SlotSize.class); freeList = null; } if (freeList == null) { freeList = new ArrayDeque<>(); freeSlots.put(size, freeList); } assert freeList != null; return freeList; } /** * Gets a free stack slot for {@code slot} or {@code null} if there is none. */ private StackSlot findFreeSlot(SimpleVirtualStackSlot slot) { assert slot != null; SlotSize size = forKind(slot.getValueKind()); if (size == SlotSize.Illegal) { return null; } Deque freeList = getOrNullFreeSlots(size); if (freeList == null) { return null; } return freeList.pollLast(); } /** * Adds a stack slot to the list of free slots. */ private void freeSlot(StackSlot slot) { SlotSize size = forKind(slot.getValueKind()); if (size == SlotSize.Illegal) { return; } getOrInitFreeSlots(size).addLast(slot); } /** * Gets the next unhandled interval and finishes handled intervals. */ private StackInterval activateNext() { if (unhandled.isEmpty()) { return null; } StackInterval next = unhandled.poll(); // finish handled intervals for (int id = next.from(); activePeekId() < id;) { finished(active.poll()); } Debug.log("active %s", next); active.add(next); return next; } /** * Gets the lowest {@link StackInterval#to() end position} of all active intervals. If there * is none {@link Integer#MAX_VALUE} is returned. */ private int activePeekId() { StackInterval first = active.peek(); if (first == null) { return Integer.MAX_VALUE; } return first.to(); } /** * Finishes {@code interval} by adding its location to the list of free stack slots. */ private void finished(StackInterval interval) { StackSlot location = interval.location(); Debug.log("finished %s (freeing %s)", interval, location); freeSlot(location); } // ==================== // step 5: assign stack slots // ==================== private void assignStackSlots(Set usePos) { for (LIRInstruction op : usePos) { op.forEachInput(assignSlot); op.forEachAlive(assignSlot); op.forEachState(assignSlot); op.forEachTemp(assignSlot); op.forEachOutput(assignSlot); } } ValueProcedure assignSlot = new ValueProcedure() { @Override public Value doValue(Value value, OperandMode mode, EnumSet flags) { if (isVirtualStackSlot(value)) { VirtualStackSlot slot = asVirtualStackSlot(value); StackInterval interval = get(slot); assert interval != null; return interval.location(); } return value; } }; // ==================== // // ==================== /** * Gets the highest instruction id. */ private int maxOpId() { return maxOpId; } private StackInterval get(VirtualStackSlot stackSlot) { return stackSlotMap[stackSlot.getId()]; } private void dumpIntervals(String label) { Debug.dump(Debug.INFO_LOG_LEVEL, new StackIntervalDumper(Arrays.copyOf(stackSlotMap, stackSlotMap.length)), label); } } }