/*

 * 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;

import static jdk.vm.ci.code.ValueUtil.isStackSlot;

import static org.graalvm.compiler.lir.LIRInstruction.OperandFlag.COMPOSITE;

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.OUTGOING;

import static org.graalvm.compiler.lir.LIRInstruction.OperandFlag.REG;

import static org.graalvm.compiler.lir.LIRInstruction.OperandFlag.STACK;

import static org.graalvm.compiler.lir.LIRInstruction.OperandFlag.UNINITIALIZED;

import static org.graalvm.compiler.lir.LIRInstruction.OperandMode.ALIVE;

import static org.graalvm.compiler.lir.LIRInstruction.OperandMode.DEF;

import static org.graalvm.compiler.lir.LIRInstruction.OperandMode.TEMP;

import static org.graalvm.compiler.lir.LIRValueUtil.isVirtualStackSlot;

import java.lang.annotation.ElementType;

import java.lang.annotation.Retention;

import java.lang.annotation.RetentionPolicy;

import java.lang.annotation.Target;

import java.util.Arrays;

import java.util.EnumMap;

import java.util.EnumSet;

import org.graalvm.compiler.graph.NodeSourcePosition;

import org.graalvm.compiler.lir.StandardOp.LoadConstantOp;

import org.graalvm.compiler.lir.StandardOp.MoveOp;

import org.graalvm.compiler.lir.StandardOp.ValueMoveOp;

import org.graalvm.compiler.lir.asm.CompilationResultBuilder;

import org.graalvm.compiler.lir.gen.LIRGenerationResult;

import jdk.vm.ci.code.RegisterValue;

import jdk.vm.ci.code.StackSlot;

import jdk.vm.ci.meta.JavaConstant;

import jdk.vm.ci.meta.Value;

/**

 * The base class for an {@code LIRInstruction}.

 */

public abstract class LIRInstruction {

    /**

     * Constants denoting how a LIR instruction uses an operand.

     */

    public enum OperandMode {

        /**

         * The value must have been defined before. It is alive before the instruction until the

         * beginning of the instruction, but not necessarily throughout the instruction. A register

         * assigned to it can also be assigned to a {@link #TEMP} or {@link #DEF} operand. The value

         * can be used again after the instruction, so the instruction must not modify the register.

         */

        USE,

        /**

         * The value must have been defined before. It is alive before the instruction and

         * throughout the instruction. A register assigned to it cannot be assigned to a

         * {@link #TEMP} or {@link #DEF} operand. The value can be used again after the instruction,

         * so the instruction must not modify the register.

         */

        ALIVE,

        /**

         * The value must not have been defined before, and must not be used after the instruction.

         * The instruction can do whatever it wants with the register assigned to it (or not use it

         * at all).

         */

        TEMP,

        /**

         * The value must not have been defined before. The instruction has to assign a value to the

         * register. The value can (and most likely will) be used after the instruction.

         */

        DEF,

    }

    @Retention(RetentionPolicy.RUNTIME)

    @Target(ElementType.FIELD)

    public static @interface Use {

        OperandFlag[] value() default OperandFlag.REG;

    }

    @Retention(RetentionPolicy.RUNTIME)

    @Target(ElementType.FIELD)

    public static @interface Alive {

        OperandFlag[] value() default OperandFlag.REG;

    }

    @Retention(RetentionPolicy.RUNTIME)

    @Target(ElementType.FIELD)

    public static @interface Temp {

        OperandFlag[] value() default OperandFlag.REG;

    }

    @Retention(RetentionPolicy.RUNTIME)

    @Target(ElementType.FIELD)

    public static @interface Def {

        OperandFlag[] value() default OperandFlag.REG;

    }

    @Retention(RetentionPolicy.RUNTIME)

    @Target(ElementType.FIELD)

    public static @interface State {

    }

    /**

     * Flags for an operand.

     */

    public enum OperandFlag {

        /**

         * The value can be a {@link RegisterValue}.

         */

        REG,

        /**

         * The value can be a {@link StackSlot}.

         */

        STACK,

        /**

         * The value can be a {@link CompositeValue}.

         */

        COMPOSITE,

        /**

         * The value can be a {@link JavaConstant}.

         */

        CONST,

        /**

         * The value can be {@link Value#ILLEGAL}.

         */

        ILLEGAL,

        /**

         * The register allocator should try to assign a certain register to improve code quality.

         * Use {@link LIRInstruction#forEachRegisterHint} to access the register hints.

         */

        HINT,

        /**

         * The value can be uninitialized, e.g., a stack slot that has not written to before. This

         * is only used to avoid false positives in verification code.

         */

        UNINITIALIZED,

        /** Outgoing block value. */

        OUTGOING,

    }

    /**

     * For validity checking of the operand flags defined by instruction subclasses.

     */

    protected static final EnumMap<OperandMode, EnumSet<OperandFlag>> ALLOWED_FLAGS;

    static {

        ALLOWED_FLAGS = new EnumMap<>(OperandMode.class);

        ALLOWED_FLAGS.put(OperandMode.USE, EnumSet.of(REG, STACK, COMPOSITE, CONST, ILLEGAL, HINT, UNINITIALIZED));

        ALLOWED_FLAGS.put(ALIVE, EnumSet.of(REG, STACK, COMPOSITE, CONST, ILLEGAL, HINT, UNINITIALIZED, OUTGOING));

        ALLOWED_FLAGS.put(TEMP, EnumSet.of(REG, STACK, COMPOSITE, ILLEGAL, HINT));

        ALLOWED_FLAGS.put(DEF, EnumSet.of(REG, STACK, COMPOSITE, ILLEGAL, HINT));

    }

    /**

     * The flags of the base and index value of an address.

     */

    protected static final EnumSet<OperandFlag> ADDRESS_FLAGS = EnumSet.of(REG, ILLEGAL);

    private final LIRInstructionClass<?> instructionClass;

    /**

     * Instruction id for register allocation.

     */

    private int id;

    /**

     * The source position of the code that generated this instruction.

     */

    private NodeSourcePosition position;

    /**

     * Constructs a new LIR instruction.

     */

    public LIRInstruction(LIRInstructionClass<? extends LIRInstruction> c) {

        instructionClass = c;

        assert c.getClazz() == this.getClass();

        id = -1;

    }

    public abstract void emitCode(CompilationResultBuilder crb);

    public final int id() {

        return id;

    }

    public final void setId(int id) {

        this.id = id;

    }

    public final NodeSourcePosition getPosition() {

        return position;

    }

    public final void setPosition(NodeSourcePosition position) {

        this.position = position;

    }

    public final String name() {

        return instructionClass.getOpcode(this);

    }

    public final boolean hasOperands() {

        return instructionClass.hasOperands() || hasState() || destroysCallerSavedRegisters();

    }

    public final boolean hasState() {

        return instructionClass.hasState(this);

    }

    public boolean destroysCallerSavedRegisters() {

        return false;

    }

    // InstructionValueProcedures

    public final void forEachInput(InstructionValueProcedure proc) {

        instructionClass.forEachUse(this, proc);

    }

    public final void forEachAlive(InstructionValueProcedure proc) {

        instructionClass.forEachAlive(this, proc);

    }

    public final void forEachTemp(InstructionValueProcedure proc) {

        instructionClass.forEachTemp(this, proc);

    }

    public final void forEachOutput(InstructionValueProcedure proc) {

        instructionClass.forEachDef(this, proc);

    }

    public final void forEachState(InstructionValueProcedure proc) {

        instructionClass.forEachState(this, proc);

    }

    // ValueProcedures

    public final void forEachInput(ValueProcedure proc) {

        instructionClass.forEachUse(this, proc);

    }

    public final void forEachAlive(ValueProcedure proc) {

        instructionClass.forEachAlive(this, proc);

    }

    public final void forEachTemp(ValueProcedure proc) {

        instructionClass.forEachTemp(this, proc);

    }

    public final void forEachOutput(ValueProcedure proc) {

        instructionClass.forEachDef(this, proc);

    }

    public final void forEachState(ValueProcedure proc) {

        instructionClass.forEachState(this, proc);

    }

    // States

    public final void forEachState(InstructionStateProcedure proc) {

        instructionClass.forEachState(this, proc);

    }

    public final void forEachState(StateProcedure proc) {

        instructionClass.forEachState(this, proc);

    }

    // InstructionValueConsumers

    public final void visitEachInput(InstructionValueConsumer proc) {

        instructionClass.visitEachUse(this, proc);

    }

    public final void visitEachAlive(InstructionValueConsumer proc) {

        instructionClass.visitEachAlive(this, proc);

    }

    public final void visitEachTemp(InstructionValueConsumer proc) {

        instructionClass.visitEachTemp(this, proc);

    }

    public final void visitEachOutput(InstructionValueConsumer proc) {

        instructionClass.visitEachDef(this, proc);

    }

    public final void visitEachState(InstructionValueConsumer proc) {

        instructionClass.visitEachState(this, proc);

    }

    // ValueConsumers

    public final void visitEachInput(ValueConsumer proc) {

        instructionClass.visitEachUse(this, proc);

    }

    public final void visitEachAlive(ValueConsumer proc) {

        instructionClass.visitEachAlive(this, proc);

    }

    public final void visitEachTemp(ValueConsumer proc) {

        instructionClass.visitEachTemp(this, proc);

    }

    public final void visitEachOutput(ValueConsumer proc) {

        instructionClass.visitEachDef(this, proc);

    }

    public final void visitEachState(ValueConsumer proc) {

        instructionClass.visitEachState(this, proc);

    }

    @SuppressWarnings("unused")

    public final Value forEachRegisterHint(Value value, OperandMode mode, InstructionValueProcedure proc) {

        return instructionClass.forEachRegisterHint(this, mode, proc);

    }

    @SuppressWarnings("unused")

    public final Value forEachRegisterHint(Value value, OperandMode mode, ValueProcedure proc) {

        return instructionClass.forEachRegisterHint(this, mode, proc);

    }

    // Checkstyle: stop

    /**

     * Returns {@code true} if the instruction is a {@link MoveOp}.

     *

     * This function is preferred to {@code instanceof MoveOp} since the type check is more

     * expensive than reading a field from {@link LIRInstructionClass}.

     */

    public final boolean isMoveOp() {

        return instructionClass.isMoveOp();

    }

    /**

     * Returns {@code true} if the instruction is a {@link ValueMoveOp}.

     *

     * This function is preferred to {@code instanceof ValueMoveOp} since the type check is more

     * expensive than reading a field from {@link LIRInstructionClass}.

     */

    public final boolean isValueMoveOp() {

        return instructionClass.isValueMoveOp();

    }

    /**

     * Returns {@code true} if the instruction is a {@link LoadConstantOp}.

     *

     * This function is preferred to {@code instanceof LoadConstantOp} since the type check is more

     * expensive than reading a field from {@link LIRInstructionClass}.

     */

    public final boolean isLoadConstantOp() {

        return instructionClass.isLoadConstantOp();

    }

    // Checkstyle: resume

    /**

     * Utility method to add stack arguments to a list of temporaries. Useful for modeling calling

     * conventions that kill outgoing argument space.

     *

     * @return additional temporaries

     */

    protected static Value[] addStackSlotsToTemporaries(Value[] parameters, Value[] temporaries) {

        int extraTemps = 0;

        for (Value p : parameters) {

            if (isStackSlot(p)) {

                extraTemps++;

            }

            assert !isVirtualStackSlot(p) : "only real stack slots in calling convention";

        }

        if (extraTemps != 0) {

            int index = temporaries.length;

            Value[] newTemporaries = Arrays.copyOf(temporaries, temporaries.length + extraTemps);

            for (Value p : parameters) {

                if (isStackSlot(p)) {

                    newTemporaries[index++] = p;

                }

            }

            return newTemporaries;

        }

        return temporaries;

    }

    public void verify() {

    }

    /**

     * Adds a comment to this instruction.

     */

    public final void setComment(LIRGenerationResult res, String comment) {

        res.setComment(this, comment);

    }

    /**

     * Gets the comment attached to this instruction.

     */

    public final String getComment(LIRGenerationResult res) {

        return res.getComment(this);

    }

    public final String toStringWithIdPrefix() {

        if (id != -1) {

            return String.format("%4d %s", id, toString());

        }

        return "     " + toString();

    }

    @Override

    public String toString() {

        return instructionClass.toString(this);

    }

    public String toString(LIRGenerationResult res) {

        String toString = toString();

        if (res == null) {

            return toString;

        }

        String comment = getComment(res);

        if (comment == null) {

            return toString;

        }

        return String.format("%s // %s", toString, comment);

    }

    public LIRInstructionClass<?> getLIRInstructionClass() {

        return instructionClass;

    }

    @Override

    public int hashCode() {

        return id;

    }

}