| /* |
| * Copyright (c) 2013, 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.hotspot; |
| |
| import static org.graalvm.compiler.lir.LIRInstruction.OperandFlag.STACK; |
| |
| import java.util.Arrays; |
| |
| import org.graalvm.compiler.core.common.LIRKind; |
| import org.graalvm.compiler.lir.LIRInstruction; |
| import org.graalvm.compiler.lir.LIRInstructionClass; |
| import org.graalvm.compiler.lir.VirtualStackSlot; |
| import org.graalvm.compiler.lir.asm.CompilationResultBuilder; |
| import org.graalvm.compiler.lir.framemap.FrameMapBuilder; |
| |
| import jdk.vm.ci.meta.AllocatableValue; |
| |
| /** |
| * Manages allocation and re-use of lock slots in a scoped manner. The slots are used in HotSpot's |
| * lightweight locking mechanism to store the mark word of an object being locked. |
| */ |
| public class HotSpotLockStack extends LIRInstruction { |
| public static final LIRInstructionClass<HotSpotLockStack> TYPE = LIRInstructionClass.create(HotSpotLockStack.class); |
| private static final AllocatableValue[] EMPTY = new AllocatableValue[0]; |
| |
| @Def({STACK}) private AllocatableValue[] locks; |
| private final FrameMapBuilder frameMapBuilder; |
| private final LIRKind slotKind; |
| |
| public HotSpotLockStack(FrameMapBuilder frameMapBuilder, LIRKind slotKind) { |
| super(TYPE); |
| this.frameMapBuilder = frameMapBuilder; |
| this.slotKind = slotKind; |
| this.locks = EMPTY; |
| } |
| |
| /** |
| * Gets a stack slot for a lock at a given lock nesting depth, allocating it first if necessary. |
| */ |
| public VirtualStackSlot makeLockSlot(int lockDepth) { |
| if (locks == EMPTY) { |
| locks = new AllocatableValue[lockDepth + 1]; |
| } else if (locks.length < lockDepth + 1) { |
| locks = Arrays.copyOf(locks, lockDepth + 1); |
| } |
| if (locks[lockDepth] == null) { |
| locks[lockDepth] = frameMapBuilder.allocateSpillSlot(slotKind); |
| } |
| return (VirtualStackSlot) locks[lockDepth]; |
| } |
| |
| @Override |
| public void emitCode(CompilationResultBuilder crb) { |
| // do nothing |
| } |
| } |