/*

 * Copyright (c) 2011, 2019, 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;

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

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

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.OUTGOING;

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

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

import java.util.ArrayList;

import java.util.Arrays;

import java.util.EnumSet;

import jdk.internal.vm.compiler.collections.EconomicSet;

import jdk.internal.vm.compiler.collections.Equivalence;

import org.graalvm.compiler.asm.Label;

import org.graalvm.compiler.core.common.GraalOptions;

import org.graalvm.compiler.core.common.cfg.AbstractBlockBase;

import org.graalvm.compiler.debug.GraalError;

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

import org.graalvm.compiler.lir.framemap.FrameMap;

import jdk.vm.ci.code.Register;

import jdk.vm.ci.code.RegisterSaveLayout;

import jdk.vm.ci.code.StackSlot;

import jdk.vm.ci.meta.AllocatableValue;

import jdk.vm.ci.meta.Constant;

import jdk.vm.ci.meta.Value;

/**

 * A collection of machine-independent LIR operations, as well as interfaces to be implemented for

 * specific kinds or LIR operations.

 */

public class StandardOp {

    /**

     * A block delimiter. Every well formed block must contain exactly one such operation and it

     * must be the last operation in the block.

     */

    public interface BlockEndOp {

    }

    public interface NullCheck {

        Value getCheckedValue();

        LIRFrameState getState();

    }

    public interface ImplicitNullCheck {

        boolean makeNullCheckFor(Value value, LIRFrameState nullCheckState, int implicitNullCheckLimit);

    }

    public interface LabelHoldingOp {

        Label getLabel();

    }

    /**

     * LIR operation that defines the position of a label.

     */

    public static final class LabelOp extends LIRInstruction implements LabelHoldingOp {

        public static final LIRInstructionClass<LabelOp> TYPE = LIRInstructionClass.create(LabelOp.class);

        public static final EnumSet<OperandFlag> incomingFlags = EnumSet.of(REG, STACK);

        /**

         * In the LIR, every register and variable must be defined before it is used. For method

         * parameters that are passed in fixed registers, exception objects passed to the exception

         * handler in a fixed register, or any other use of a fixed register not defined in this

         * method, an artificial definition is necessary. To avoid spill moves to be inserted

         * between the label at the beginning of a block an an actual definition in the second

         * instruction of a block, the registers are defined here in the label.

         */

        @Def({REG, STACK}) private Value[] incomingValues;

        private final Label label;

        private final boolean align;

        private int numbPhis;

        public LabelOp(Label label, boolean align) {

            super(TYPE);

            this.label = label;

            this.align = align;

            this.incomingValues = Value.NO_VALUES;

            this.numbPhis = 0;

        }

        public void setPhiValues(Value[] values) {

            setIncomingValues(values);

            setNumberOfPhis(values.length);

        }

        private void setNumberOfPhis(int numPhis) {

            assert numbPhis == 0;

            numbPhis = numPhis;

        }

        public int getPhiSize() {

            return numbPhis;

        }

        public void setIncomingValues(Value[] values) {

            assert this.incomingValues.length == 0;

            assert values != null;

            this.incomingValues = values;

        }

        public int getIncomingSize() {

            return incomingValues.length;

        }

        public Value getIncomingValue(int idx) {

            assert checkRange(idx);

            return incomingValues[idx];

        }

        public void clearIncomingValues() {

            incomingValues = Value.NO_VALUES;

        }

        public void addIncomingValues(Value[] values) {

            if (incomingValues.length == 0) {

                setIncomingValues(values);

                return;

            }

            int t = incomingValues.length + values.length;

            Value[] newArray = new Value[t];

            System.arraycopy(incomingValues, 0, newArray, 0, incomingValues.length);

            System.arraycopy(values, 0, newArray, incomingValues.length, values.length);

            incomingValues = newArray;

        }

        private boolean checkRange(int idx) {

            return idx < incomingValues.length;

        }

        @Override

        public void emitCode(CompilationResultBuilder crb) {

            if (align) {

                crb.asm.align(GraalOptions.LoopHeaderAlignment.getValue(crb.getOptions()));

            }

            crb.asm.bind(label);

        }

        @Override

        public Label getLabel() {

            return label;

        }

        /**

         * @return true if this label acts as a PhiIn.

         */

        public boolean isPhiIn() {

            return getPhiSize() > 0;

        }

        public void forEachIncomingValue(InstructionValueProcedure proc) {

            for (int i = 0; i < incomingValues.length; i++) {

                incomingValues[i] = proc.doValue(this, incomingValues[i], OperandMode.DEF, incomingFlags);

            }

        }

    }

    /**

     * LIR operation that is an unconditional jump to a {@link #destination()}.

     */

    public static class JumpOp extends LIRInstruction implements BlockEndOp {

        public static final LIRInstructionClass<JumpOp> TYPE = LIRInstructionClass.create(JumpOp.class);

        public static final EnumSet<OperandFlag> outgoingFlags = EnumSet.of(REG, STACK, CONST, OUTGOING);

        @Alive({REG, STACK, CONST, OUTGOING}) private Value[] outgoingValues;

        private final LabelRef destination;

        public JumpOp(LabelRef destination) {

            this(TYPE, destination);

        }

        protected JumpOp(LIRInstructionClass<? extends JumpOp> c, LabelRef destination) {

            super(c);

            this.destination = destination;

            this.outgoingValues = Value.NO_VALUES;

        }

        @Override

        public void emitCode(CompilationResultBuilder crb) {

            if (!crb.isSuccessorEdge(destination)) {

                crb.asm.jmp(destination.label());

            }

        }

        public LabelRef destination() {

            return destination;

        }

        public void setPhiValues(Value[] values) {

            assert this.outgoingValues.length == 0;

            assert values != null;

            this.outgoingValues = values;

        }

        public int getPhiSize() {

            return outgoingValues.length;

        }

        public Value getOutgoingValue(int idx) {

            assert checkRange(idx);

            return outgoingValues[idx];

        }

        public void clearOutgoingValues() {

            outgoingValues = Value.NO_VALUES;

        }

        private boolean checkRange(int idx) {

            return idx < outgoingValues.length;

        }

    }

    /**

     * Marker interface for a LIR operation that is a conditional jump.

     */

    public interface BranchOp extends BlockEndOp {

    }

    /**

     * Marker interface for a LIR operation that moves a value to {@link #getResult()}.

     */

    public interface MoveOp {

        AllocatableValue getResult();

        // Checkstyle: stop

        static MoveOp asMoveOp(LIRInstruction op) {

            return (MoveOp) op;

        }

        // Checkstyle: resume

        static boolean isMoveOp(LIRInstruction op) {

            return op.isMoveOp();

        }

    }

    /**

     * Marker interface for a LIR operation that moves some non-constant value to another location.

     */

    public interface ValueMoveOp extends MoveOp {

        AllocatableValue getInput();

        // Checkstyle: stop

        static ValueMoveOp asValueMoveOp(LIRInstruction op) {

            return (ValueMoveOp) op;

        }

        // Checkstyle: resume

        static boolean isValueMoveOp(LIRInstruction op) {

            return op.isValueMoveOp();

        }

    }

    /**

     * Marker interface for a LIR operation that loads a {@link #getConstant()}.

     */

    public interface LoadConstantOp extends MoveOp {

        Constant getConstant();

        // Checkstyle: stop

        static LoadConstantOp asLoadConstantOp(LIRInstruction op) {

            return (LoadConstantOp) op;

        }

        // Checkstyle: resume

        static boolean isLoadConstantOp(LIRInstruction op) {

            return op.isLoadConstantOp();

        }

    }

    /**

     * An operation that saves registers to the stack. The set of saved registers can be

     * {@linkplain #remove(EconomicSet) pruned} and a mapping from registers to the frame slots in

     * which they are saved can be {@linkplain #getMap(FrameMap) retrieved}.

     */

    public abstract static class SaveRegistersOp extends LIRInstruction {

        public static final LIRInstructionClass<SaveRegistersOp> TYPE = LIRInstructionClass.create(SaveRegistersOp.class);

        /**

         * The registers (potentially) saved by this operation.

         */

        protected final Register[] savedRegisters;

        /**

         * The slots to which the registers are saved.

         */

        @Def(STACK) protected final AllocatableValue[] slots;

        /**

         *

         * @param savedRegisters the registers saved by this operation which may be subject to

         *            {@linkplain #remove(EconomicSet) pruning}

         * @param savedRegisterLocations the slots to which the registers are saved

         */

        protected SaveRegistersOp(LIRInstructionClass<? extends SaveRegistersOp> c, Register[] savedRegisters, AllocatableValue[] savedRegisterLocations) {

            super(c);

            assert Arrays.asList(savedRegisterLocations).stream().allMatch(LIRValueUtil::isVirtualStackSlot);

            this.savedRegisters = savedRegisters;

            this.slots = savedRegisterLocations;

        }

        /**

         * Prunes {@code doNotSave} from the registers saved by this operation.

         *

         * @param doNotSave registers that should not be saved by this operation

         * @return the number of registers pruned

         */

        public int remove(EconomicSet<Register> doNotSave) {

            return prune(doNotSave, savedRegisters);

        }

        /**

         * Gets a map from the saved registers saved by this operation to the frame slots in which

         * they are saved.

         *

         * @param frameMap used to {@linkplain FrameMap#offsetForStackSlot(StackSlot) convert} a

         *            virtual slot to a frame slot index

         */

        public RegisterSaveLayout getMap(FrameMap frameMap) {

            int total = 0;

            for (int i = 0; i < savedRegisters.length; i++) {

                if (savedRegisters[i] != null) {

                    total++;

                }

            }

            Register[] keys = new Register[total];

            int[] values = new int[total];

            if (total != 0) {

                int mapIndex = 0;

                for (int i = 0; i < savedRegisters.length; i++) {

                    if (savedRegisters[i] != null) {

                        keys[mapIndex] = savedRegisters[i];

                        assert isStackSlot(slots[i]) : "not a StackSlot: " + slots[i];

                        StackSlot slot = asStackSlot(slots[i]);

                        values[mapIndex] = indexForStackSlot(frameMap, slot);

                        mapIndex++;

                    }

                }

                assert mapIndex == total;

            }

            return new RegisterSaveLayout(keys, values);

        }

        public Register[] getSavedRegisters() {

            return savedRegisters;

        }

        public EconomicSet<Register> getSaveableRegisters() {

            EconomicSet<Register> registers = EconomicSet.create(Equivalence.IDENTITY);

            for (Register r : savedRegisters) {

                registers.add(r);

            }

            return registers;

        }

        public AllocatableValue[] getSlots() {

            return slots;

        }

        @Override

        public abstract void emitCode(CompilationResultBuilder crb);

        static int prune(EconomicSet<Register> toRemove, Register[] registers) {

            int pruned = 0;

            for (int i = 0; i < registers.length; i++) {

                if (registers[i] != null) {

                    if (toRemove.contains(registers[i])) {

                        registers[i] = null;

                        pruned++;

                    }

                }

            }

            return pruned;

        }

        /**

         * Computes the index of a stack slot relative to slot 0. This is also the bit index of

         * stack slots in the reference map.

         *

         * @param slot a stack slot

         * @return the index of the stack slot

         */

        private static int indexForStackSlot(FrameMap frameMap, StackSlot slot) {

            assert frameMap.offsetForStackSlot(slot) % frameMap.getTarget().wordSize == 0;

            int value = frameMap.offsetForStackSlot(slot) / frameMap.getTarget().wordSize;

            return value;

        }

    }

    /**

     * Marker interface for an operation that restores the registers saved by

     * {@link SaveRegistersOp}.

     */

    public interface RestoreRegistersOp {

    }

    /**

     * Marker interface for an operation that kills some set register and stack locations.

     */

    public interface ZapRegistersOp {

    }

    /**

     * A LIR operation that does nothing. If the operation records its position, it can be

     * subsequently {@linkplain #replace(LIR, LIRInstruction) replaced}.

     */

    public static final class NoOp extends LIRInstruction {

        public static final LIRInstructionClass<NoOp> TYPE = LIRInstructionClass.create(NoOp.class);

        /**

         * The block in which this instruction is located.

         */

        final AbstractBlockBase<?> block;

        /**

         * The block index of this instruction.

         */

        final int index;

        public NoOp(AbstractBlockBase<?> block, int index) {

            super(TYPE);

            this.block = block;

            this.index = index;

        }

        public void replace(LIR lir, LIRInstruction replacement) {

            ArrayList<LIRInstruction> instructions = lir.getLIRforBlock(block);

            assert instructions.get(index).equals(this) : String.format("Replacing the wrong instruction: %s instead of %s", instructions.get(index), this);

            instructions.set(index, replacement);

        }

        public void remove(LIR lir) {

            ArrayList<LIRInstruction> instructions = lir.getLIRforBlock(block);

            assert instructions.get(index).equals(this) : String.format("Removing the wrong instruction: %s instead of %s", instructions.get(index), this);

            instructions.remove(index);

        }

        @Override

        public void emitCode(CompilationResultBuilder crb) {

            if (block != null) {

                throw new GraalError(this + " should have been replaced");

            }

        }

    }

    @Opcode("BLACKHOLE")

    public static final class BlackholeOp extends LIRInstruction {

        public static final LIRInstructionClass<BlackholeOp> TYPE = LIRInstructionClass.create(BlackholeOp.class);

        @Use({REG, STACK, CONST}) private Value value;

        public BlackholeOp(Value value) {

            super(TYPE);

            this.value = value;

        }

        @Override

        public void emitCode(CompilationResultBuilder crb) {

            // do nothing, just keep value alive until at least here

        }

    }

    public static final class BindToRegisterOp extends LIRInstruction {

        public static final LIRInstructionClass<BindToRegisterOp> TYPE = LIRInstructionClass.create(BindToRegisterOp.class);

        @Use({REG}) private Value value;

        public BindToRegisterOp(Value value) {

            super(TYPE);

            this.value = value;

        }

        @Override

        public void emitCode(CompilationResultBuilder crb) {

            // do nothing, just keep value alive until at least here

        }

    }

    @Opcode("SPILLREGISTERS")

    public static final class SpillRegistersOp extends LIRInstruction {