001/*
002 * Copyright (c) 2009, 2012, Oracle and/or its affiliates. All rights reserved.
003 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
004 *
005 * This code is free software; you can redistribute it and/or modify it
006 * under the terms of the GNU General Public License version 2 only, as
007 * published by the Free Software Foundation.
008 *
009 * This code is distributed in the hope that it will be useful, but WITHOUT
010 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
011 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
012 * version 2 for more details (a copy is included in the LICENSE file that
013 * accompanied this code).
014 *
015 * You should have received a copy of the GNU General Public License version
016 * 2 along with this work; if not, write to the Free Software Foundation,
017 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
018 *
019 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
020 * or visit www.oracle.com if you need additional information or have any
021 * questions.
022 */
023package com.oracle.graal.lir.sparc;
024
025import static com.oracle.graal.lir.LIRInstruction.OperandFlag.*;
026import static jdk.internal.jvmci.code.ValueUtil.*;
027import jdk.internal.jvmci.code.*;
028import jdk.internal.jvmci.meta.*;
029
030import com.oracle.graal.asm.sparc.*;
031import com.oracle.graal.lir.*;
032import com.oracle.graal.lir.StandardOp.NoOp;
033import com.oracle.graal.lir.asm.*;
034
035/**
036 * Loads the constant section base into a register.
037 *
038 * <p>
039 * Layout:
040 *
041 * <pre>
042 * +----constant section----+--pad--+---code section--+
043 * |<-------------------_------------------->|
044 *                      ^- Constant section base pointer
045 * </pre>
046 *
047 * The constant section base pointer is placed as such that the lowest offset -4096 points to the
048 * start of the constant section.
049 * <p>
050 * If the constant section grows beyond 8k size, the immediate addressing cannot be used anymore; in
051 * this case absolute addressing (without using the base pointer is used). See also:
052 * CodeInstaller::pd_patch_DataSectionReference
053 *
054 * @see SPARCMove#loadFromConstantTable(CompilationResultBuilder, SPARCMacroAssembler, Kind,
055 *      Register, Register, SPARCDelayedControlTransfer, Runnable)
056 */
057public class SPARCLoadConstantTableBaseOp extends SPARCLIRInstruction {
058    public static final LIRInstructionClass<SPARCLoadConstantTableBaseOp> TYPE = LIRInstructionClass.create(SPARCLoadConstantTableBaseOp.class);
059    public static final SizeEstimate SIZE = SizeEstimate.create(9);
060
061    private final NoOp placeHolder;
062    @Def({REG}) private AllocatableValue base;
063
064    public SPARCLoadConstantTableBaseOp(Variable base, NoOp placeHolder) {
065        super(TYPE, SIZE);
066        this.base = base;
067        this.placeHolder = placeHolder;
068    }
069
070    @Override
071    public void emitCode(CompilationResultBuilder crb, SPARCMacroAssembler masm) {
072        Register baseRegister = asRegister(base);
073        int beforePosition = masm.position();
074        masm.rdpc(baseRegister);
075        // Must match with CodeInstaller::pd_patch_DataSectionReference
076        masm.add(baseRegister, (int) SPARCAssembler.minSimm(13), baseRegister);
077        masm.sub(baseRegister, beforePosition, baseRegister);
078    }
079
080    public AllocatableValue getResult() {
081        return base;
082    }
083
084    public void setAlive(LIR lir, boolean alive) {
085        if (alive) {
086            placeHolder.replace(lir, this);
087        } else {
088            placeHolder.remove(lir);
089        }
090    }
091}