java/9 : jdk.internal.vm.compiler/org.graalvm.compiler.lir.sparc/src/org/graalvm/compiler/lir/sparc/SPARCControlFlow.java

SPARCControlFlow
https://openjdk.java.net/
GPLv2 + Classpath Exception
/*
 * Copyright (c) 2013, 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.sparc;

import static org.graalvm.compiler.asm.sparc.SPARCAssembler.BPCC;
import static org.graalvm.compiler.asm.sparc.SPARCAssembler.CBCOND;
import static org.graalvm.compiler.asm.sparc.SPARCAssembler.FBPCC;
import static org.graalvm.compiler.asm.sparc.SPARCAssembler.INSTRUCTION_SIZE;
import static org.graalvm.compiler.asm.sparc.SPARCAssembler.isSimm10;
import static org.graalvm.compiler.asm.sparc.SPARCAssembler.isSimm11;
import static org.graalvm.compiler.asm.sparc.SPARCAssembler.isSimm13;
import static org.graalvm.compiler.asm.sparc.SPARCAssembler.isSimm5;
import static org.graalvm.compiler.asm.sparc.SPARCAssembler.Annul.ANNUL;
import static org.graalvm.compiler.asm.sparc.SPARCAssembler.Annul.NOT_ANNUL;
import static org.graalvm.compiler.asm.sparc.SPARCAssembler.BranchPredict.PREDICT_NOT_TAKEN;
import static org.graalvm.compiler.asm.sparc.SPARCAssembler.BranchPredict.PREDICT_TAKEN;
import static org.graalvm.compiler.asm.sparc.SPARCAssembler.CC.Fcc0;
import static org.graalvm.compiler.asm.sparc.SPARCAssembler.CC.Icc;
import static org.graalvm.compiler.asm.sparc.SPARCAssembler.CC.Xcc;
import static org.graalvm.compiler.asm.sparc.SPARCAssembler.ConditionFlag.Always;
import static org.graalvm.compiler.asm.sparc.SPARCAssembler.ConditionFlag.Equal;
import static org.graalvm.compiler.asm.sparc.SPARCAssembler.ConditionFlag.F_Equal;
import static org.graalvm.compiler.asm.sparc.SPARCAssembler.ConditionFlag.F_Greater;
import static org.graalvm.compiler.asm.sparc.SPARCAssembler.ConditionFlag.F_GreaterOrEqual;
import static org.graalvm.compiler.asm.sparc.SPARCAssembler.ConditionFlag.F_Less;
import static org.graalvm.compiler.asm.sparc.SPARCAssembler.ConditionFlag.F_LessOrEqual;
import static org.graalvm.compiler.asm.sparc.SPARCAssembler.ConditionFlag.F_UnorderedGreaterOrEqual;
import static org.graalvm.compiler.asm.sparc.SPARCAssembler.ConditionFlag.F_UnorderedOrEqual;
import static org.graalvm.compiler.asm.sparc.SPARCAssembler.ConditionFlag.F_UnorderedOrGreater;
import static org.graalvm.compiler.asm.sparc.SPARCAssembler.ConditionFlag.F_UnorderedOrLess;
import static org.graalvm.compiler.asm.sparc.SPARCAssembler.ConditionFlag.F_UnorderedOrLessOrEqual;
import static org.graalvm.compiler.asm.sparc.SPARCAssembler.ConditionFlag.Greater;
import static org.graalvm.compiler.asm.sparc.SPARCAssembler.ConditionFlag.GreaterEqual;
import static org.graalvm.compiler.asm.sparc.SPARCAssembler.ConditionFlag.GreaterEqualUnsigned;
import static org.graalvm.compiler.asm.sparc.SPARCAssembler.ConditionFlag.GreaterUnsigned;
import static org.graalvm.compiler.asm.sparc.SPARCAssembler.ConditionFlag.Less;
import static org.graalvm.compiler.asm.sparc.SPARCAssembler.ConditionFlag.LessEqual;
import static org.graalvm.compiler.asm.sparc.SPARCAssembler.ConditionFlag.LessEqualUnsigned;
import static org.graalvm.compiler.asm.sparc.SPARCAssembler.ConditionFlag.LessUnsigned;
import static org.graalvm.compiler.asm.sparc.SPARCAssembler.ConditionFlag.NotEqual;
import static org.graalvm.compiler.asm.sparc.SPARCAssembler.Op3s.Subcc;
import static org.graalvm.compiler.lir.LIRInstruction.OperandFlag.CONST;
import static org.graalvm.compiler.lir.LIRInstruction.OperandFlag.HINT;
import static org.graalvm.compiler.lir.LIRInstruction.OperandFlag.ILLEGAL;
import static org.graalvm.compiler.lir.LIRInstruction.OperandFlag.REG;
import static org.graalvm.compiler.lir.LIRValueUtil.asJavaConstant;
import static org.graalvm.compiler.lir.LIRValueUtil.isConstantValue;
import static org.graalvm.compiler.lir.LIRValueUtil.isJavaConstant;
import static org.graalvm.compiler.lir.sparc.SPARCMove.const2reg;
import static org.graalvm.compiler.lir.sparc.SPARCOP3Op.emitOp3;
import static jdk.vm.ci.code.ValueUtil.asRegister;
import static jdk.vm.ci.sparc.SPARC.CPU;
import static jdk.vm.ci.sparc.SPARC.g0;
import static jdk.vm.ci.sparc.SPARCKind.WORD;
import static jdk.vm.ci.sparc.SPARCKind.XWORD;

import java.util.ArrayList;
import java.util.EnumSet;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.graalvm.compiler.asm.Assembler;
import org.graalvm.compiler.asm.Assembler.LabelHint;
import org.graalvm.compiler.asm.Label;
import org.graalvm.compiler.asm.NumUtil;
import org.graalvm.compiler.asm.sparc.SPARCAssembler;
import org.graalvm.compiler.asm.sparc.SPARCAssembler.BranchPredict;
import org.graalvm.compiler.asm.sparc.SPARCAssembler.CC;
import org.graalvm.compiler.asm.sparc.SPARCAssembler.CMOV;
import org.graalvm.compiler.asm.sparc.SPARCAssembler.ConditionFlag;
import org.graalvm.compiler.asm.sparc.SPARCMacroAssembler;
import org.graalvm.compiler.asm.sparc.SPARCMacroAssembler.ScratchRegister;
import org.graalvm.compiler.core.common.calc.Condition;
import org.graalvm.compiler.debug.GraalError;
import org.graalvm.compiler.lir.LIRInstructionClass;
import org.graalvm.compiler.lir.LabelRef;
import org.graalvm.compiler.lir.Opcode;
import org.graalvm.compiler.lir.StandardOp;
import org.graalvm.compiler.lir.SwitchStrategy;
import org.graalvm.compiler.lir.SwitchStrategy.BaseSwitchClosure;
import org.graalvm.compiler.lir.Variable;
import org.graalvm.compiler.lir.asm.CompilationResultBuilder;

import jdk.vm.ci.code.Register;
import jdk.vm.ci.meta.AllocatableValue;
import jdk.vm.ci.meta.Constant;
import jdk.vm.ci.meta.JavaConstant;
import jdk.vm.ci.meta.PlatformKind;
import jdk.vm.ci.meta.Value;
import jdk.vm.ci.sparc.SPARC.CPUFeature;
import jdk.vm.ci.sparc.SPARCKind;

public class SPARCControlFlow {
    // This describes the maximum offset between the first emitted (load constant in to scratch,
    // if does not fit into simm5 of cbcond) instruction and the final branch instruction
    private static final int maximumSelfOffsetInstructions = 2;

    public static final class ReturnOp extends SPARCBlockEndOp {
        public static final LIRInstructionClass<ReturnOp> TYPE = LIRInstructionClass.create(ReturnOp.class);
        public static final SizeEstimate SIZE = SizeEstimate.create(2);

        @Use({REG, ILLEGAL}) protected Value x;

        public ReturnOp(Value x) {
            super(TYPE, SIZE);
            this.x = x;
        }

        @Override
        public void emitCode(CompilationResultBuilder crb, SPARCMacroAssembler masm) {
            emitCodeHelper(crb, masm);
        }

        public static void emitCodeHelper(CompilationResultBuilder crb, SPARCMacroAssembler masm) {
            masm.ret();
            // On SPARC we always leave the frame (in the delay slot).
            crb.frameContext.leave(crb);
        }
    }

    public static final class CompareBranchOp extends SPARCBlockEndOp implements SPARCDelayedControlTransfer {
        public static final LIRInstructionClass<CompareBranchOp> TYPE = LIRInstructionClass.create(CompareBranchOp.class);
        public static final SizeEstimate SIZE = SizeEstimate.create(3);
        static final EnumSet<SPARCKind> SUPPORTED_KINDS = EnumSet.of(XWORD, WORD);

        @Use({REG}) protected Value x;
        @Use({REG, CONST}) protected Value y;
        private ConditionFlag conditionFlag;
        protected final LabelRef trueDestination;
        protected LabelHint trueDestinationHint;
        protected final LabelRef falseDestination;
        protected LabelHint falseDestinationHint;
        protected final SPARCKind kind;
        protected final boolean unorderedIsTrue;
        private boolean emitted = false;
        private int delaySlotPosition = -1;
        private double trueDestinationProbability;

        public CompareBranchOp(Value x, Value y, Condition condition, LabelRef trueDestination, LabelRef falseDestination, SPARCKind kind, boolean unorderedIsTrue, double trueDestinationProbability) {
            super(TYPE, SIZE);
            this.x = x;
            this.y = y;
            this.trueDestination = trueDestination;
            this.falseDestination = falseDestination;
            this.kind = kind;
            this.unorderedIsTrue = unorderedIsTrue;
            this.trueDestinationProbability = trueDestinationProbability;
            conditionFlag = fromCondition(kind.isInteger(), condition, unorderedIsTrue);
        }

        @Override
        public void emitCode(CompilationResultBuilder crb, SPARCMacroAssembler masm) {
            if (emitted) { // Only if delayed control transfer is used we must check this
                assert masm.position() - delaySlotPosition == 4 : "Only one instruction can be stuffed into the delay slot";
            }
            if (!emitted) {
                requestHints(masm);
                int targetPosition = getTargetPosition(masm);
                if (canUseShortBranch(crb, masm, targetPosition)) {
                    emitted = emitShortCompareBranch(crb, masm);
                }
                if (!emitted) { // No short compare/branch was used, so we go into fallback
                    emitted = emitLongCompareBranch(crb, masm, true);
                    emitted = true;
                }
            }
            assert emitted;
        }

        private boolean emitLongCompareBranch(CompilationResultBuilder crb, SPARCMacroAssembler masm, boolean withDelayedNop) {
            emitOp3(masm, Subcc, x, y);
            return emitBranch(crb, masm, kind, conditionFlag, trueDestination, falseDestination, withDelayedNop, trueDestinationProbability);
        }

        private static int getTargetPosition(Assembler asm) {
            return asm.position() + maximumSelfOffsetInstructions * asm.target.wordSize;
        }

        @Override
        public void emitControlTransfer(CompilationResultBuilder crb, SPARCMacroAssembler masm) {
            requestHints(masm);
            // When we use short branches, no delay slot is available
            int targetPosition = getTargetPosition(masm);
            if (!canUseShortBranch(crb, masm, targetPosition)) {
                emitted = emitLongCompareBranch(crb, masm, false);
                if (emitted) {
                    delaySlotPosition = masm.position();
                }
            }
        }

        private void requestHints(SPARCMacroAssembler masm) {
            if (trueDestinationHint == null) {
                this.trueDestinationHint = masm.requestLabelHint(trueDestination.label());
            }
            if (falseDestinationHint == null) {
                this.falseDestinationHint = masm.requestLabelHint(falseDestination.label());
            }
        }

        Tries to use the emit the compare/branch instruction.

CBcond has follwing limitations

Immediate field is only 5 bit and is on the right
Jump offset is maximum of -+512 instruction

We get from outside

at least one of trueDestination falseDestination is within reach of +-512
instructions
two registers OR one register and a constant which fits simm13

We do:

find out which target needs to be branched conditionally
find out if fall-through is possible, if not, a unconditional branch is needed after
cbcond (needJump=true)
if no fall through: we need to put the closer jump into the cbcond branch and the
farther into the jmp (unconditional branch)
if constant on the left side, mirror to be on the right
if constant on right does not fit into simm5, put it into a scratch register
Params: crb – 
masm – 
Returns: true if the branch could be emitted/**
         * Tries to use the emit the compare/branch instruction.
         * <p>
         * CBcond has follwing limitations
         * <ul>
         * <li>Immediate field is only 5 bit and is on the right
         * <li>Jump offset is maximum of -+512 instruction
         *
         * <p>
         * We get from outside
         * <ul>
         * <li>at least one of trueDestination falseDestination is within reach of +-512
         * instructions
         * <li>two registers OR one register and a constant which fits simm13
         *
         * <p>
         * We do:
         * <ul>
         * <li>find out which target needs to be branched conditionally
         * <li>find out if fall-through is possible, if not, a unconditional branch is needed after
         * cbcond (needJump=true)
         * <li>if no fall through: we need to put the closer jump into the cbcond branch and the
         * farther into the jmp (unconditional branch)
         * <li>if constant on the left side, mirror to be on the right
         * <li>if constant on right does not fit into simm5, put it into a scratch register
         *
         * @param crb
         * @param masm
         * @return true if the branch could be emitted
         */
        private boolean emitShortCompareBranch(CompilationResultBuilder crb, SPARCMacroAssembler masm) {
            ConditionFlag actualConditionFlag = conditionFlag;
            Label actualTrueTarget = trueDestination.label();
            Label actualFalseTarget = falseDestination.label();
            Label tmpTarget;
            boolean needJump;
            if (crb.isSuccessorEdge(trueDestination)) {
                actualConditionFlag = conditionFlag.negate();
                tmpTarget = actualTrueTarget;
                actualTrueTarget = actualFalseTarget;
                actualFalseTarget = tmpTarget;
                needJump = false;
            } else {
                needJump = !crb.isSuccessorEdge(falseDestination);
                int targetPosition = getTargetPosition(masm);
                if (needJump && !isShortBranch(masm, targetPosition, trueDestinationHint, actualTrueTarget)) {
                    // we have to jump in either way, so we must put the shorter
                    // branch into the actualTarget as only one of the two jump targets
                    // is guaranteed to be simm10
                    actualConditionFlag = actualConditionFlag.negate();
                    tmpTarget = actualTrueTarget;
                    actualTrueTarget = actualFalseTarget;
                    actualFalseTarget = tmpTarget;
                }
            }
            emitCBCond(masm, x, y, actualTrueTarget, actualConditionFlag);
            if (needJump) {
                masm.jmp(actualFalseTarget);
                masm.nop();
            }
            return true;
        }

        private void emitCBCond(SPARCMacroAssembler masm, Value actualX, Value actualY, Label actualTrueTarget, ConditionFlag cFlag) {
            PlatformKind xKind = actualX.getPlatformKind();
            boolean isLong = kind == SPARCKind.XWORD;
            if (isJavaConstant(actualY)) {
                JavaConstant c = asJavaConstant(actualY);
                long constantY = c.isNull() ? 0 : c.asLong();
                assert NumUtil.isInt(constantY);
                CBCOND.emit(masm, cFlag, isLong, asRegister(actualX, xKind), (int) constantY, actualTrueTarget);
            } else {
                CBCOND.emit(masm, cFlag, isLong, asRegister(actualX, xKind), asRegister(actualY, xKind), actualTrueTarget);
            }
        }

        private boolean canUseShortBranch(CompilationResultBuilder crb, SPARCAssembler asm, int position) {
            if (!asm.hasFeature(CPUFeature.CBCOND)) {
                return false;
            }
            if (!((SPARCKind) x.getPlatformKind()).isInteger()) {
                return false;
            }
            // Do not use short branch, if the y value is a constant and does not fit into simm5 but
            // fits into simm13; this means the code with CBcond would be longer as the code without
            // CBcond.
            if (isJavaConstant(y) && !isSimm5(asJavaConstant(y)) && isSimm13(asJavaConstant(y))) {
                return false;
            }
            boolean hasShortJumpTarget = false;
            if (!crb.isSuccessorEdge(trueDestination)) {
                hasShortJumpTarget |= isShortBranch(asm, position, trueDestinationHint, trueDestination.label());
            }
            if (!crb.isSuccessorEdge(falseDestination)) {
                hasShortJumpTarget |= isShortBranch(asm, position, falseDestinationHint, falseDestination.label());
            }
            return hasShortJumpTarget;
        }

        @Override
        public void resetState() {
            emitted = false;
            delaySlotPosition = -1;
        }

        @Override
        public void verify() {
            super.verify();
            assert SUPPORTED_KINDS.contains(kind) : kind;
            assert !isConstantValue(x);
            assert x.getPlatformKind().equals(kind) && (isConstantValue(y) || y.getPlatformKind().equals(kind)) : x + " " + y;
        }
    }

    public static boolean isShortBranch(SPARCAssembler asm, int position, LabelHint hint, Label label) {
        int disp = 0;
        boolean dispValid = true;
        if (label.isBound()) {
            disp = label.position() - position;
        } else if (hint != null && hint.isValid()) {
            disp = hint.getTarget() - hint.getPosition();
        } else {
            dispValid = false;
        }
        if (dispValid) {
            if (disp < 0) {
                disp -= maximumSelfOffsetInstructions * asm.target.wordSize;
            } else {
                disp += maximumSelfOffsetInstructions * asm.target.wordSize;
            }
            return isSimm10(disp >> 2);
        } else if (hint == null) {
            asm.requestLabelHint(label);
        }
        return false;
    }

    public static final class BranchOp extends SPARCBlockEndOp implements StandardOp.BranchOp {
        public static final LIRInstructionClass<BranchOp> TYPE = LIRInstructionClass.create(BranchOp.class);
        public static final SizeEstimate SIZE = SizeEstimate.create(2);
        protected final ConditionFlag conditionFlag;
        protected final LabelRef trueDestination;
        protected final LabelRef falseDestination;
        protected final SPARCKind kind;
        protected final double trueDestinationProbability;

        public BranchOp(ConditionFlag conditionFlag, LabelRef trueDestination, LabelRef falseDestination, SPARCKind kind, double trueDestinationProbability) {
            super(TYPE, SIZE);
            this.trueDestination = trueDestination;
            this.falseDestination = falseDestination;
            this.kind = kind;
            this.conditionFlag = conditionFlag;
            this.trueDestinationProbability = trueDestinationProbability;
        }

        @Override
        public void emitCode(CompilationResultBuilder crb, SPARCMacroAssembler masm) {
            emitBranch(crb, masm, kind, conditionFlag, trueDestination, falseDestination, true, trueDestinationProbability);
        }
    }

    private static boolean emitBranch(CompilationResultBuilder crb, SPARCMacroAssembler masm, SPARCKind kind, ConditionFlag conditionFlag, LabelRef trueDestination, LabelRef falseDestination,
                    boolean withDelayedNop, double trueDestinationProbability) {
        Label actualTarget;
        ConditionFlag actualConditionFlag;
        boolean needJump;
        BranchPredict predictTaken;
        if (falseDestination != null && crb.isSuccessorEdge(trueDestination)) {
            actualConditionFlag = conditionFlag != null ? conditionFlag.negate() : null;
            actualTarget = falseDestination.label();
            needJump = false;
            predictTaken = trueDestinationProbability < .5d ? PREDICT_TAKEN : PREDICT_NOT_TAKEN;
        } else {
            actualConditionFlag = conditionFlag;
            actualTarget = trueDestination.label();
            needJump = falseDestination != null && !crb.isSuccessorEdge(falseDestination);
            predictTaken = trueDestinationProbability > .5d ? PREDICT_TAKEN : PREDICT_NOT_TAKEN;
        }
        if (!withDelayedNop && needJump) {
            // We cannot make use of the delay slot when we jump in true-case and false-case
            return false;
        }
        if (kind.isFloat()) {
            FBPCC.emit(masm, Fcc0, actualConditionFlag, NOT_ANNUL, predictTaken, actualTarget);
        } else {
            assert kind.isInteger();
            CC cc = kind.equals(WORD) ? Icc : Xcc;
            BPCC.emit(masm, cc, actualConditionFlag, NOT_ANNUL, predictTaken, actualTarget);
        }
        if (withDelayedNop) {
            masm.nop();  // delay slot
        }
        if (needJump) {
            masm.jmp(falseDestination.label());
        }
        return true;
    }

    public static class StrategySwitchOp extends SPARCBlockEndOp {
        public static final LIRInstructionClass<StrategySwitchOp> TYPE = LIRInstructionClass.create(StrategySwitchOp.class);
        protected Constant[] keyConstants;
        private final LabelRef[] keyTargets;
        private LabelRef defaultTarget;
        @Alive({REG}) protected Value key;
        @Alive({REG, ILLEGAL}) protected Value constantTableBase;
        @Temp({REG}) protected Value scratch;
        protected final SwitchStrategy strategy;
        private final Map<Label, LabelHint> labelHints;
        private final List<Label> conditionalLabels = new ArrayList<>();

        public StrategySwitchOp(Value constantTableBase, SwitchStrategy strategy, LabelRef[] keyTargets, LabelRef defaultTarget, Value key, Value scratch) {
            this(TYPE, constantTableBase, strategy, keyTargets, defaultTarget, key, scratch);
        }

        protected StrategySwitchOp(LIRInstructionClass<? extends StrategySwitchOp> c, Value constantTableBase, SwitchStrategy strategy, LabelRef[] keyTargets, LabelRef defaultTarget, Value key,
                        Value scratch) {
            super(c);
            this.strategy = strategy;
            this.keyConstants = strategy.getKeyConstants();
            this.keyTargets = keyTargets;
            this.defaultTarget = defaultTarget;
            this.constantTableBase = constantTableBase;
            this.key = key;
            this.scratch = scratch;
            this.labelHints = new HashMap<>();
            assert keyConstants.length == keyTargets.length;
            assert keyConstants.length == strategy.keyProbabilities.length;
        }

        @Override
        public void emitCode(final CompilationResultBuilder crb, final SPARCMacroAssembler masm) {
            final Register keyRegister = asRegister(key);
            final Register constantBaseRegister = AllocatableValue.ILLEGAL.equals(constantTableBase) ? g0 : asRegister(constantTableBase);
            strategy.run(new SwitchClosure(keyRegister, constantBaseRegister, crb, masm));
        }

        public class SwitchClosure extends BaseSwitchClosure {
            private int conditionalLabelPointer = 0;

            protected final Register keyRegister;
            protected final Register constantBaseRegister;
            protected final CompilationResultBuilder crb;
            protected final SPARCMacroAssembler masm;

            protected SwitchClosure(Register keyRegister, Register constantBaseRegister, CompilationResultBuilder crb, SPARCMacroAssembler masm) {
                super(crb, masm, keyTargets, defaultTarget);
                this.keyRegister = keyRegister;
                this.constantBaseRegister = constantBaseRegister;
                this.crb = crb;
                this.masm = masm;
            }

            This method caches the generated labels over two assembly passes to get information
about branch lengths.
/**
             * This method caches the generated labels over two assembly passes to get information
             * about branch lengths.
             */
            @Override
            public Label conditionalJump(int index, Condition condition) {
                Label label;
                if (conditionalLabelPointer <= conditionalLabels.size()) {
                    label = new Label();
                    conditionalLabels.add(label);
                    conditionalLabelPointer = conditionalLabels.size();
                } else {
                    // TODO: (sa) We rely here on the order how the labels are generated during
                    // code generation; if the order is not stable ower two assembly passes, the
                    // result can be wrong
                    label = conditionalLabels.get(conditionalLabelPointer++);
                }
                conditionalJump(index, condition, label);
                return label;
            }

            @Override
            protected void conditionalJump(int index, Condition condition, Label target) {
                JavaConstant constant = (JavaConstant) keyConstants[index];
                CC conditionCode;
                Long bits = constant.asLong();
                switch (constant.getJavaKind()) {
                    case Char:
                    case Byte:
                    case Short:
                    case Int:
                        conditionCode = CC.Icc;
                        break;
                    case Long:
                        conditionCode = CC.Xcc;
                        break;
                    default:
                        throw new GraalError("switch only supported for int, long and object");
                }
                ConditionFlag conditionFlag = fromCondition(keyRegister.getRegisterCategory().equals(CPU), condition, false);
                LabelHint hint = requestHint(masm, target);
                boolean isShortConstant = isSimm5(constant);
                int cbCondPosition = masm.position();
                if (!isShortConstant) { // Load constant takes one instruction
                    cbCondPosition += INSTRUCTION_SIZE;
                }
                boolean canUseShortBranch = masm.hasFeature(CPUFeature.CBCOND) && isShortBranch(masm, cbCondPosition, hint, target);
                if (bits != null && canUseShortBranch) {
                    if (isShortConstant) {
                        CBCOND.emit(masm, conditionFlag, conditionCode == Xcc, keyRegister, (int) (long) bits, target);
                    } else {
                        Register scratchRegister = asRegister(scratch);
                        const2reg(crb, masm, scratch, constantBaseRegister, (JavaConstant) keyConstants[index], SPARCDelayedControlTransfer.DUMMY);
                        CBCOND.emit(masm, conditionFlag, conditionCode == Xcc, keyRegister, scratchRegister, target);
                    }
                } else {
                    if (bits != null && isSimm13(constant)) {
                        masm.cmp(keyRegister, (int) (long) bits); // Cast is safe
                    } else {
                        Register scratchRegister = asRegister(scratch);
                        const2reg(crb, masm, scratch, constantBaseRegister, (JavaConstant) keyConstants[index], SPARCDelayedControlTransfer.DUMMY);
                        masm.cmp(keyRegister, scratchRegister);
                    }
                    BPCC.emit(masm, conditionCode, conditionFlag, ANNUL, PREDICT_TAKEN, target);
                    masm.nop();  // delay slot
                }
            }
        }

        protected LabelHint requestHint(SPARCMacroAssembler masm, Label label) {
            LabelHint hint = labelHints.get(label);
            if (hint == null) {
                hint = masm.requestLabelHint(label);
                labelHints.put(label, hint);
            }
            return hint;
        }

        protected int estimateEmbeddedSize(Constant c) {
            JavaConstant v = (JavaConstant) c;
            if (!SPARCAssembler.isSimm13(v)) {
                return v.getJavaKind().getByteCount();
            } else {
                return 0;
            }
        }

        @Override
        public SizeEstimate estimateSize() {
            int constantBytes = 0;
            for (Constant c : keyConstants) {
                constantBytes += estimateEmbeddedSize(c);
            }
            return new SizeEstimate(4 * keyTargets.length, constantBytes);
        }
    }

    public static final class TableSwitchOp extends SPARCBlockEndOp {
        public static final LIRInstructionClass<TableSwitchOp> TYPE = LIRInstructionClass.create(TableSwitchOp.class);

        private final int lowKey;
        private final LabelRef defaultTarget;
        private final LabelRef[] targets;
        @Alive protected Value index;
        @Temp protected Value scratch;

        public TableSwitchOp(final int lowKey, final LabelRef defaultTarget, final LabelRef[] targets, Variable index, Variable scratch) {
            super(TYPE);
            this.lowKey = lowKey;
            this.defaultTarget = defaultTarget;
            this.targets = targets;
            this.index = index;
            this.scratch = scratch;
        }

        @Override
        public void emitCode(CompilationResultBuilder crb, SPARCMacroAssembler masm) {
            Register value = asRegister(index, SPARCKind.WORD);
            Register scratchReg = asRegister(scratch, SPARCKind.XWORD);

            // Compare index against jump table bounds
            int highKey = lowKey + targets.length - 1;

            // subtract the low value from the switch value
            if (isSimm13(lowKey)) {
                masm.sub(value, lowKey, scratchReg);
            } else {
                try (ScratchRegister sc = masm.getScratchRegister()) {
                    Register scratch2 = sc.getRegister();
                    masm.setx(lowKey, scratch2, false);
                    masm.sub(value, scratch2, scratchReg);
                }
            }
            int upperLimit = highKey - lowKey;
            try (ScratchRegister sc = masm.getScratchRegister()) {
                Register scratch2 = sc.getRegister();
                if (isSimm13(upperLimit)) {
                    masm.cmp(scratchReg, upperLimit);
                } else {
                    masm.setx(upperLimit, scratch2, false);
                    masm.cmp(scratchReg, upperLimit);
                }

                // Jump to default target if index is not within the jump table
                if (defaultTarget != null) {
                    BPCC.emit(masm, Icc, GreaterUnsigned, NOT_ANNUL, PREDICT_TAKEN, defaultTarget.label());
                    masm.nop();  // delay slot
                }

                // Load jump table entry into scratch and jump to it
                masm.sll(scratchReg, 3, scratchReg); // Multiply by 8
                // Zero the left bits sll with shcnt>0 does not mask upper 32 bits
                masm.srl(scratchReg, 0, scratchReg);
                masm.rdpc(scratch2);

                // The jump table follows four instructions after rdpc
                masm.add(scratchReg, 4 * 4, scratchReg);
                masm.jmpl(scratch2, scratchReg, g0);
            }
            masm.nop();

            // Emit jump table entries
            for (LabelRef target : targets) {
                BPCC.emit(masm, Xcc, Always, NOT_ANNUL, PREDICT_TAKEN, target.label());
                masm.nop(); // delay slot
            }
        }

        @Override
        public SizeEstimate estimateSize() {
            return SizeEstimate.create(17 + targets.length * 2);
        }
    }

    @Opcode("CMOVE")
    public static final class CondMoveOp extends SPARCLIRInstruction {
        public static final LIRInstructionClass<CondMoveOp> TYPE = LIRInstructionClass.create(CondMoveOp.class);

        @Def({REG, HINT}) protected Value result;
        @Use({REG, CONST}) protected Value trueValue;
        @Use({REG, CONST}) protected Value falseValue;

        private final ConditionFlag condition;
        private final CC cc;
        private final CMOV cmove;

        public CondMoveOp(CMOV cmove, CC cc, ConditionFlag condition, Value trueValue, Value falseValue, Value result) {
            super(TYPE);
            this.result = result;
            this.condition = condition;
            this.trueValue = trueValue;
            this.falseValue = falseValue;
            this.cc = cc;
            this.cmove = cmove;
        }

        @Override
        public void emitCode(CompilationResultBuilder crb, SPARCMacroAssembler masm) {
            if (result.equals(trueValue)) { // We have the true value in place, do he opposite
                cmove(masm, condition.negate(), falseValue);
            } else if (result.equals(falseValue)) {
                cmove(masm, condition, trueValue);
            } else { // We have to move one of the input values to the result
                ConditionFlag actualCondition = condition;
                Value actualTrueValue = trueValue;
                Value actualFalseValue = falseValue;
                if (isJavaConstant(falseValue) && isSimm11(asJavaConstant(falseValue))) {
                    actualCondition = condition.negate();
                    actualTrueValue = falseValue;
                    actualFalseValue = trueValue;
                }
                SPARCMove.move(crb, masm, result, actualFalseValue, SPARCDelayedControlTransfer.DUMMY);
                cmove(masm, actualCondition, actualTrueValue);
            }
        }

        private void cmove(SPARCMacroAssembler masm, ConditionFlag localCondition, Value value) {
            if (isConstantValue(value)) {
                cmove.emit(masm, localCondition, cc, asImmediate(asJavaConstant(value)), asRegister(result));
            } else {
                cmove.emit(masm, localCondition, cc, asRegister(value), asRegister(result));
            }
        }

        @Override
        public SizeEstimate estimateSize() {
            int constantSize = 0;
            if (isJavaConstant(trueValue) && !SPARCAssembler.isSimm13(asJavaConstant(trueValue))) {
                constantSize += trueValue.getPlatformKind().getSizeInBytes();
            }
            if (isJavaConstant(falseValue) && !SPARCAssembler.isSimm13(asJavaConstant(falseValue))) {
                constantSize += trueValue.getPlatformKind().getSizeInBytes();
            }
            return SizeEstimate.create(3, constantSize);
        }
    }

    public static ConditionFlag fromCondition(boolean integer, Condition cond, boolean unorderedIsTrue) {
        if (integer) {
            switch (cond) {
                case EQ:
                    return Equal;
                case NE:
                    return NotEqual;
                case BT:
                    return LessUnsigned;
                case LT:
                    return Less;
                case BE:
                    return LessEqualUnsigned;
                case LE:
                    return LessEqual;
                case AE:
                    return GreaterEqualUnsigned;
                case GE:
                    return GreaterEqual;
                case AT:
                    return GreaterUnsigned;
                case GT:
                    return Greater;
            }
            throw GraalError.shouldNotReachHere("Unimplemented for: " + cond);
        } else {
            switch (cond) {
                case EQ:
                    return unorderedIsTrue ? F_UnorderedOrEqual : F_Equal;
                case NE:
                    return ConditionFlag.F_NotEqual;
                case LT:
                    return unorderedIsTrue ? F_UnorderedOrLess : F_Less;
                case LE:
                    return unorderedIsTrue ? F_UnorderedOrLessOrEqual : F_LessOrEqual;
                case GE:
                    return unorderedIsTrue ? F_UnorderedGreaterOrEqual : F_GreaterOrEqual;
                case GT:
                    return unorderedIsTrue ? F_UnorderedOrGreater : F_Greater;
            }
            throw GraalError.shouldNotReachHere("Unkown condition: " + cond);
        }
    }
}
Params:	crb – masm –
Returns:	true if the branch could be emitted
/

java/ 9/ jdk.internal.vm.compiler/org.graalvm.compiler.lir.sparc/src/org/graalvm/compiler/lir/sparc/SPARCControlFlow.java
