/*
 * Copyright (c) 2009, 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
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 */
package org.graalvm.compiler.lir;

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

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.debug.Debug;
import org.graalvm.compiler.debug.DebugCounter;
import org.graalvm.compiler.graph.NodeSourcePosition;
import org.graalvm.compiler.lir.asm.CompilationResultBuilder;

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 LIRInstruction. /**
 * The base class for an {@code LIRInstruction}.
 */
public abstract class LIRInstruction {
    
Constants denoting how a LIR instruction uses an operand.
/**
     * 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 TEMP or DEF operand. The value can be used again after the instruction, so the instruction must not modify the register. /**
         * 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 TEMP or DEF operand. The value can be used again after the instruction, so the instruction must not modify the register. /**
         * 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).
/**
         * 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.
/**
         * 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.
/**
     * Flags for an operand.
     */
    public enum OperandFlag {
        
The value can be a RegisterValue. /**
         * The value can be a {@link RegisterValue}.
         */
        REG,

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

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

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

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

        
The register allocator should try to assign a certain register to improve code quality. Use LIRInstruction.forEachRegisterHint to access the register hints. /**
         * 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.
/**
         * 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 block value. */
        OUTGOING,
    }

    
For validity checking of the operand flags defined by instruction subclasses.
/**
     * 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.
/**
     * 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.
/**
     * Instruction id for register allocation.
     */
    private int id;

    
The source position of the code that generated this instruction.
/**
     * The source position of the code that generated this instruction.
     */
    private NodeSourcePosition position;

    private static final DebugCounter LIR_NODE_COUNT = Debug.counter("LIRNodes");

    
Constructs a new LIR instruction.
/**
     * Constructs a new LIR instruction.
     */
    public LIRInstruction(LIRInstructionClass<? extends LIRInstruction> c) {
        LIR_NODE_COUNT.increment();
        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);
    }

    
Utility method to add stack arguments to a list of temporaries. Useful for modeling calling
conventions that kill outgoing argument space.
Returns:
additional temporaries/**
     * 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() {
    }

    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 LIRInstructionClass<?> getLIRInstructionClass() {
        return instructionClass;
    }
}