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package org.graalvm.compiler.core.aarch64;

import jdk.vm.ci.aarch64.AArch64Kind;
import jdk.vm.ci.code.CodeUtil;
import jdk.vm.ci.meta.AllocatableValue;
import jdk.vm.ci.meta.JavaKind;
import jdk.vm.ci.meta.Value;
import jdk.internal.vm.compiler.collections.EconomicMap;
import jdk.internal.vm.compiler.collections.Equivalence;
import org.graalvm.compiler.asm.aarch64.AArch64MacroAssembler;
import org.graalvm.compiler.core.common.LIRKind;
import org.graalvm.compiler.core.common.calc.CanonicalCondition;
import org.graalvm.compiler.core.gen.NodeMatchRules;
import org.graalvm.compiler.core.match.ComplexMatchResult;
import org.graalvm.compiler.core.match.MatchRule;
import org.graalvm.compiler.graph.Node;
import org.graalvm.compiler.lir.LIRFrameState;
import org.graalvm.compiler.lir.LabelRef;
import org.graalvm.compiler.lir.Variable;
import org.graalvm.compiler.lir.aarch64.AArch64ArithmeticOp;
import org.graalvm.compiler.lir.aarch64.AArch64BitFieldOp;
import org.graalvm.compiler.lir.aarch64.AArch64ControlFlow;
import org.graalvm.compiler.lir.gen.LIRGeneratorTool;
import org.graalvm.compiler.nodes.ConstantNode;
import org.graalvm.compiler.nodes.DeoptimizingNode;
import org.graalvm.compiler.nodes.FixedNode;
import org.graalvm.compiler.nodes.IfNode;
import org.graalvm.compiler.nodes.NodeView;
import org.graalvm.compiler.nodes.ValueNode;
import org.graalvm.compiler.nodes.calc.AddNode;
import org.graalvm.compiler.nodes.calc.AndNode;
import org.graalvm.compiler.nodes.calc.BinaryNode;
import org.graalvm.compiler.nodes.calc.IntegerLessThanNode;
import org.graalvm.compiler.nodes.calc.LeftShiftNode;
import org.graalvm.compiler.nodes.calc.NotNode;
import org.graalvm.compiler.nodes.calc.OrNode;
import org.graalvm.compiler.nodes.calc.RightShiftNode;
import org.graalvm.compiler.nodes.calc.SubNode;
import org.graalvm.compiler.nodes.calc.UnsignedRightShiftNode;
import org.graalvm.compiler.nodes.calc.XorNode;
import org.graalvm.compiler.nodes.memory.Access;

public class AArch64NodeMatchRules extends NodeMatchRules {
    private static final EconomicMap<Class<? extends Node>, AArch64ArithmeticOp> nodeOpMap;
    private static final EconomicMap<Class<? extends BinaryNode>, AArch64BitFieldOp.BitFieldOpCode> bitFieldOpMap;
    private static final EconomicMap<Class<? extends BinaryNode>, AArch64MacroAssembler.ShiftType> shiftTypeMap;

    static {
        nodeOpMap = EconomicMap.create(Equivalence.IDENTITY, 5);
        nodeOpMap.put(AddNode.class, AArch64ArithmeticOp.ADD);
        nodeOpMap.put(SubNode.class, AArch64ArithmeticOp.SUB);
        nodeOpMap.put(AndNode.class, AArch64ArithmeticOp.AND);
        nodeOpMap.put(OrNode.class, AArch64ArithmeticOp.OR);
        nodeOpMap.put(XorNode.class, AArch64ArithmeticOp.XOR);

        bitFieldOpMap = EconomicMap.create(Equivalence.IDENTITY, 2);
        bitFieldOpMap.put(UnsignedRightShiftNode.class, AArch64BitFieldOp.BitFieldOpCode.UBFX);
        bitFieldOpMap.put(LeftShiftNode.class, AArch64BitFieldOp.BitFieldOpCode.UBFIZ);

        shiftTypeMap = EconomicMap.create(Equivalence.IDENTITY, 3);
        shiftTypeMap.put(LeftShiftNode.class, AArch64MacroAssembler.ShiftType.LSL);
        shiftTypeMap.put(RightShiftNode.class, AArch64MacroAssembler.ShiftType.ASR);
        shiftTypeMap.put(UnsignedRightShiftNode.class, AArch64MacroAssembler.ShiftType.LSR);
    }

    public AArch64NodeMatchRules(LIRGeneratorTool gen) {
        super(gen);
    }

    protected LIRFrameState getState(Access access) {
        if (access instanceof DeoptimizingNode) {
            return state((DeoptimizingNode) access);
        }
        return null;
    }

    protected AArch64Kind getMemoryKind(Access access) {
        return (AArch64Kind) gen.getLIRKind(access.asNode().stamp(NodeView.DEFAULT)).getPlatformKind();
    }

    private AllocatableValue moveSp(AllocatableValue value) {
        return getLIRGeneratorTool().moveSp(value);
    }

    private ComplexMatchResult emitBitField(AArch64BitFieldOp.BitFieldOpCode op, ValueNode value, int lsb, int width) {
        assert op != null;
        assert value.getStackKind().isNumericInteger();

        return builder -> {
            Value a = operand(value);
            Variable result = gen.newVariable(LIRKind.combine(a));
            AllocatableValue src = moveSp(gen.asAllocatable(a));
            gen.append(new AArch64BitFieldOp(op, result, src, lsb, width));
            return result;
        };
    }

    private ComplexMatchResult emitBinaryShift(AArch64ArithmeticOp op, ValueNode value, BinaryNode shift,
                    boolean isShiftNot) {
        AArch64MacroAssembler.ShiftType shiftType = shiftTypeMap.get(shift.getClass());
        assert shiftType != null;
        assert value.getStackKind().isNumericInteger();
        assert shift.getX().getStackKind().isNumericInteger();
        assert shift.getY() instanceof ConstantNode;

        return builder -> {
            Value a = operand(value);
            Value b = operand(shift.getX());
            Variable result = gen.newVariable(LIRKind.combine(a, b));
            AllocatableValue x = moveSp(gen.asAllocatable(a));
            AllocatableValue y = moveSp(gen.asAllocatable(b));
            int shiftAmount = shift.getY().asJavaConstant().asInt();
            gen.append(new AArch64ArithmeticOp.BinaryShiftOp(op, result, x, y, shiftType, shiftAmount, isShiftNot));
            return result;
        };
    }

    private ComplexMatchResult emitBitTestAndBranch(FixedNode trueSuccessor, FixedNode falseSuccessor,
                    ValueNode value, double trueProbability, int nbits) {
        return builder -> {
            LabelRef trueDestination = getLIRBlock(trueSuccessor);
            LabelRef falseDestination = getLIRBlock(falseSuccessor);
            AllocatableValue src = moveSp(gen.asAllocatable(operand(value)));
            gen.append(new AArch64ControlFlow.BitTestAndBranchOp(trueDestination, falseDestination, src,
                            trueProbability, nbits));
            return null;
        };
    }

    @MatchRule("(And (UnsignedRightShift=shift a Constant=b) Constant=c)")
    @MatchRule("(LeftShift=shift (And a Constant=c) Constant=b)")
    public ComplexMatchResult unsignedBitField(BinaryNode shift, ValueNode a, ConstantNode b, ConstantNode c) {
        JavaKind srcKind = a.getStackKind();
        assert srcKind.isNumericInteger();
        AArch64BitFieldOp.BitFieldOpCode op = bitFieldOpMap.get(shift.getClass());
        assert op != null;
        int distance = b.asJavaConstant().asInt();
        long mask = c.asJavaConstant().asLong();

        // The Java(R) Language Specification CHAPTER 15.19 Shift Operators says:
        // "If the promoted type of the left-hand operand is int(long), then only the five(six)
        // lowest-order bits of the right-hand operand are used as the shift distance."
        distance = distance & (srcKind == JavaKind.Int ? 0x1f : 0x3f);

        // Constraint 1: Mask plus one should be a power-of-2 integer.
        if (!CodeUtil.isPowerOf2(mask + 1)) {
            return null;
        }
        int width = CodeUtil.log2(mask + 1);
        int srcBits = srcKind.getBitCount();
        // Constraint 2: Bit field width is less than 31(63) for int(long) as any bit field move
        // operations can be done by a single shift instruction if the width is 31(63).
        if (width >= srcBits - 1) {
            return null;
        }
        // Constraint 3: Sum of bit field width and the shift distance is less or equal to 32(64)
        // for int(long) as the specification of AArch64 bit field instructions.
        if (width + distance > srcBits) {
            return null;
        }
        return emitBitField(op, a, distance, width);
    }

    @MatchRule("(Add=binary a (LeftShift=shift b Constant))")
    @MatchRule("(Add=binary a (RightShift=shift b Constant))")
    @MatchRule("(Add=binary a (UnsignedRightShift=shift b Constant))")
    @MatchRule("(Sub=binary a (LeftShift=shift b Constant))")
    @MatchRule("(Sub=binary a (RightShift=shift b Constant))")
    @MatchRule("(Sub=binary a (UnsignedRightShift=shift b Constant))")
    public ComplexMatchResult addSubShift(BinaryNode binary, ValueNode a, BinaryNode shift) {
        AArch64ArithmeticOp op = nodeOpMap.get(binary.getClass());
        assert op != null;
        return emitBinaryShift(op, a, shift, false);
    }

    @MatchRule("(And=binary a (LeftShift=shift b Constant))")
    @MatchRule("(And=binary a (RightShift=shift b Constant))")
    @MatchRule("(And=binary a (UnsignedRightShift=shift b Constant))")
    @MatchRule("(Or=binary a (LeftShift=shift b Constant))")
    @MatchRule("(Or=binary a (RightShift=shift b Constant))")
    @MatchRule("(Or=binary a (UnsignedRightShift=shift b Constant))")
    @MatchRule("(Xor=binary a (LeftShift=shift b Constant))")
    @MatchRule("(Xor=binary a (RightShift=shift b Constant))")
    @MatchRule("(Xor=binary a (UnsignedRightShift=shift b Constant))")
    @MatchRule("(And=binary a (Not (LeftShift=shift b Constant)))")
    @MatchRule("(And=binary a (Not (RightShift=shift b Constant)))")
    @MatchRule("(And=binary a (Not (UnsignedRightShift=shift b Constant)))")
    @MatchRule("(Or=binary a (Not (LeftShift=shift b Constant)))")
    @MatchRule("(Or=binary a (Not (RightShift=shift b Constant)))")
    @MatchRule("(Or=binary a (Not (UnsignedRightShift=shift b Constant)))")
    @MatchRule("(Xor=binary a (Not (LeftShift=shift b Constant)))")
    @MatchRule("(Xor=binary a (Not (RightShift=shift b Constant)))")
    @MatchRule("(Xor=binary a (Not (UnsignedRightShift=shift b Constant)))")
    public ComplexMatchResult logicShift(BinaryNode binary, ValueNode a, BinaryNode shift) {
        AArch64ArithmeticOp op = nodeOpMap.get(binary.getClass());
        assert op != null;
        ValueNode operand = binary.getX() == a ? binary.getY() : binary.getX();
        boolean isShiftNot = operand instanceof NotNode;
        return emitBinaryShift(op, a, shift, isShiftNot);
    }

    @MatchRule("(Mul (Negate a) b)")
    @MatchRule("(Negate (Mul a b))")
    public ComplexMatchResult multiplyNegate(ValueNode a, ValueNode b) {
        if (a.getStackKind().isNumericInteger() && b.getStackKind().isNumericInteger()) {
            return builder -> getArithmeticLIRGenerator().emitMNeg(operand(a), operand(b));
        }
        return null;
    }

    @MatchRule("(Add=binary (Mul a b) c)")
    @MatchRule("(Sub=binary c (Mul a b))")
    public ComplexMatchResult multiplyAddSub(BinaryNode binary, ValueNode a, ValueNode b, ValueNode c) {
        JavaKind kindA = a.getStackKind();
        JavaKind kindB = b.getStackKind();
        JavaKind kindC = c.getStackKind();
        if (!kindA.isNumericInteger() || !kindB.isNumericInteger() || !kindC.isNumericInteger()) {
            return null;
        }

        if (binary instanceof AddNode) {
            return builder -> getArithmeticLIRGenerator().emitMAdd(operand(a), operand(b), operand(c));
        }
        return builder -> getArithmeticLIRGenerator().emitMSub(operand(a), operand(b), operand(c));
    }

    /**
     * ((x & (1 << n)) == 0) -> tbz/tbnz n label.
     */
    @MatchRule("(If (IntegerTest value Constant=a))")
    public ComplexMatchResult testBitAndBranch(IfNode root, ValueNode value, ConstantNode a) {
        if (value.getStackKind().isNumericInteger()) {
            long constant = a.asJavaConstant().asLong();
            if (Long.bitCount(constant) == 1) {
                return emitBitTestAndBranch(root.trueSuccessor(), root.falseSuccessor(), value,
                                root.getTrueSuccessorProbability(), Long.numberOfTrailingZeros(constant));
            }
        }
        return null;
    }

    /**
     * if x < 0 <=> tbz x, sizeOfBits(x) - 1, label.
     */
    @MatchRule("(If (IntegerLessThan=lessNode x Constant=y))")
    public ComplexMatchResult checkNegativeAndBranch(IfNode root, IntegerLessThanNode lessNode, ValueNode x, ConstantNode y) {
        JavaKind xKind = x.getStackKind();
        assert xKind.isNumericInteger();
        if (y.isJavaConstant() && (0 == y.asJavaConstant().asLong()) && lessNode.condition().equals(CanonicalCondition.LT)) {
            return emitBitTestAndBranch(root.falseSuccessor(), root.trueSuccessor(), x,
                            1.0 - root.getTrueSuccessorProbability(), xKind.getBitCount() - 1);
        }
        return null;
    }

    @Override
    public AArch64LIRGenerator getLIRGeneratorTool() {
        return (AArch64LIRGenerator) gen;
    }

    protected AArch64ArithmeticLIRGenerator getArithmeticLIRGenerator() {
        return (AArch64ArithmeticLIRGenerator) getLIRGeneratorTool().getArithmetic();
    }
}