/*

 * Copyright (c) 2017, 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.core.gen;

import java.util.ArrayDeque;

import java.util.Arrays;

import java.util.Queue;

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

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

import org.graalvm.compiler.debug.CounterKey;

import org.graalvm.compiler.debug.DebugContext;

import org.graalvm.compiler.debug.GraalError;

import org.graalvm.compiler.lir.ConstantValue;

import org.graalvm.compiler.lir.LIRFrameState;

import org.graalvm.compiler.lir.LabelRef;

import org.graalvm.compiler.lir.Variable;

import org.graalvm.compiler.nodes.ConstantNode;

import org.graalvm.compiler.nodes.FrameState;

import org.graalvm.compiler.nodes.ValueNode;

import org.graalvm.compiler.nodes.spi.NodeValueMap;

import org.graalvm.compiler.nodes.util.GraphUtil;

import org.graalvm.compiler.nodes.virtual.EscapeObjectState;

import org.graalvm.compiler.nodes.virtual.VirtualBoxingNode;

import org.graalvm.compiler.nodes.virtual.VirtualObjectNode;

import org.graalvm.compiler.serviceprovider.GraalServices;

import org.graalvm.compiler.virtual.nodes.MaterializedObjectState;

import org.graalvm.compiler.virtual.nodes.VirtualObjectState;

import jdk.vm.ci.code.BytecodeFrame;

import jdk.vm.ci.code.VirtualObject;

import jdk.vm.ci.meta.JavaConstant;

import jdk.vm.ci.meta.JavaKind;

import jdk.vm.ci.meta.JavaType;

import jdk.vm.ci.meta.JavaValue;

import jdk.vm.ci.meta.ResolvedJavaField;

import jdk.vm.ci.meta.ResolvedJavaType;

import jdk.vm.ci.meta.Value;

/**

 * Builds {@link LIRFrameState}s from {@link FrameState}s.

 */

public class DebugInfoBuilder {

    protected final NodeValueMap nodeValueMap;

    protected final DebugContext debug;

    public DebugInfoBuilder(NodeValueMap nodeValueMap, DebugContext debug) {

        this.nodeValueMap = nodeValueMap;

        this.debug = debug;

    }

    private static final JavaValue[] NO_JAVA_VALUES = {};

    private static final JavaKind[] NO_JAVA_KINDS = {};

    protected final EconomicMap<VirtualObjectNode, VirtualObject> virtualObjects = EconomicMap.create(Equivalence.IDENTITY);

    protected final EconomicMap<VirtualObjectNode, EscapeObjectState> objectStates = EconomicMap.create(Equivalence.IDENTITY);

    protected final Queue<VirtualObjectNode> pendingVirtualObjects = new ArrayDeque<>();

    public LIRFrameState build(FrameState topState, LabelRef exceptionEdge) {

        assert virtualObjects.size() == 0;

        assert objectStates.size() == 0;

        assert pendingVirtualObjects.size() == 0;

        // collect all VirtualObjectField instances:

        FrameState current = topState;

        do {

            if (current.virtualObjectMappingCount() > 0) {

                for (EscapeObjectState state : current.virtualObjectMappings()) {

                    if (!objectStates.containsKey(state.object())) {

                        if (!(state instanceof MaterializedObjectState) || ((MaterializedObjectState) state).materializedValue() != state.object()) {

                            objectStates.put(state.object(), state);

                        }

                    }

                }

            }

            current = current.outerFrameState();

        } while (current != null);

        BytecodeFrame frame = computeFrameForState(topState);

        VirtualObject[] virtualObjectsArray = null;

        if (virtualObjects.size() != 0) {

            // fill in the VirtualObject values

            VirtualObjectNode vobjNode;

            while ((vobjNode = pendingVirtualObjects.poll()) != null) {

                VirtualObject vobjValue = virtualObjects.get(vobjNode);

                assert vobjValue.getValues() == null;

                JavaValue[] values;

                JavaKind[] slotKinds;

                int entryCount = vobjNode.entryCount();

                if (entryCount == 0) {

                    values = NO_JAVA_VALUES;

                    slotKinds = NO_JAVA_KINDS;

                } else {

                    values = new JavaValue[entryCount];

                    slotKinds = new JavaKind[entryCount];

                }

                if (values.length > 0) {

                    VirtualObjectState currentField = (VirtualObjectState) objectStates.get(vobjNode);

                    assert currentField != null;

                    int pos = 0;

                    for (int i = 0; i < entryCount; i++) {

                        ValueNode value = currentField.values().get(i);

                        if (value == null) {

                            JavaKind entryKind = vobjNode.entryKind(i);

                            values[pos] = JavaConstant.defaultForKind(entryKind.getStackKind());

                            slotKinds[pos] = entryKind.getStackKind();

                            pos++;

                        } else if (!value.isConstant() || value.asJavaConstant().getJavaKind() != JavaKind.Illegal) {

                            values[pos] = toJavaValue(value);

                            slotKinds[pos] = toSlotKind(value);

                            pos++;

                        } else {

                            assert value.getStackKind() == JavaKind.Illegal;

                            ValueNode previousValue = currentField.values().get(i - 1);

                            assert (previousValue != null && previousValue.getStackKind().needsTwoSlots()) : vobjNode + " " + i +

                                            " " + previousValue + " " + currentField.values().snapshot();

                            if (previousValue == null || !previousValue.getStackKind().needsTwoSlots()) {

                                // Don't allow the IllegalConstant to leak into the debug info

                                JavaKind entryKind = vobjNode.entryKind(i);

                                values[pos] = JavaConstant.defaultForKind(entryKind.getStackKind());

                                slotKinds[pos] = entryKind.getStackKind();

                                pos++;

                            }

                        }

                    }

                    if (pos != entryCount) {

                        values = Arrays.copyOf(values, pos);

                        slotKinds = Arrays.copyOf(slotKinds, pos);

                    }

                }

                assert checkValues(vobjValue.getType(), values, slotKinds);

                vobjValue.setValues(values, slotKinds);

            }

            virtualObjectsArray = new VirtualObject[virtualObjects.size()];

            int index = 0;

            for (VirtualObject value : virtualObjects.getValues()) {

                virtualObjectsArray[index++] = value;

            }

            virtualObjects.clear();

        }

        objectStates.clear();

        return newLIRFrameState(exceptionEdge, frame, virtualObjectsArray);

    }

    private boolean checkValues(ResolvedJavaType type, JavaValue[] values, JavaKind[] slotKinds) {

        assert (values == null) == (slotKinds == null);

        if (values != null) {

            assert values.length == slotKinds.length;

            if (!type.isArray()) {

                ResolvedJavaField[] fields = type.getInstanceFields(true);

                int fieldIndex = 0;

                for (int valueIndex = 0; valueIndex < values.length; valueIndex++, fieldIndex++) {

                    ResolvedJavaField field = fields[fieldIndex];

                    JavaKind valKind = slotKinds[valueIndex].getStackKind();

                    JavaKind fieldKind = storageKind(field.getType());

                    if ((valKind == JavaKind.Double || valKind == JavaKind.Long) && fieldKind == JavaKind.Int) {

                        assert fieldIndex + 1 < fields.length : String.format("Not enough fields for fieldIndex = %d valueIndex = %d %s %s", fieldIndex, valueIndex, Arrays.toString(fields),

                                        Arrays.toString(values));

                        assert storageKind(fields[fieldIndex + 1].getType()) == JavaKind.Int : String.format("fieldIndex = %d valueIndex = %d %s %s %s", fieldIndex, valueIndex,

                                        storageKind(fields[fieldIndex + 1].getType()), Arrays.toString(fields),

                                        Arrays.toString(values));

                        fieldIndex++;

                    } else {

                        assert valKind == fieldKind.getStackKind() : field + ": " + valKind + " != " + fieldKind;

                    }

                }

                assert fields.length == fieldIndex : type + ": fields=" + Arrays.toString(fields) + ", field values=" + Arrays.toString(values);

            } else {

                JavaKind componentKind = storageKind(type.getComponentType()).getStackKind();

                if (componentKind == JavaKind.Object) {

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

                        assert slotKinds[i].isObject() : slotKinds[i] + " != " + componentKind;

                    }

                } else {

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

                        assert slotKinds[i] == componentKind || componentKind.getBitCount() >= slotKinds[i].getBitCount() ||

                                        (componentKind == JavaKind.Int && slotKinds[i].getBitCount() >= JavaKind.Int.getBitCount()) : slotKinds[i] + " != " + componentKind;

                    }

                }

            }

        }

        return true;

    }

    /*

     * Customization point for subclasses. For example, Word types have a kind Object, but are

     * internally stored as a primitive value. We do not know about Word types here, but subclasses

     * do know.

     */

    protected JavaKind storageKind(JavaType type) {

        return type.getJavaKind();

    }

    protected LIRFrameState newLIRFrameState(LabelRef exceptionEdge, BytecodeFrame frame, VirtualObject[] virtualObjectsArray) {

        return new LIRFrameState(frame, virtualObjectsArray, exceptionEdge);

    }

    protected BytecodeFrame computeFrameForState(FrameState state) {

        try {

            assert state.bci != BytecodeFrame.INVALID_FRAMESTATE_BCI;

            assert state.bci != BytecodeFrame.UNKNOWN_BCI;

            assert state.bci != BytecodeFrame.BEFORE_BCI || state.locksSize() == 0;

            assert state.bci != BytecodeFrame.AFTER_BCI || state.locksSize() == 0;

            assert state.bci != BytecodeFrame.AFTER_EXCEPTION_BCI || state.locksSize() == 0;

            assert !(state.getMethod().isSynchronized() && state.bci != BytecodeFrame.BEFORE_BCI && state.bci != BytecodeFrame.AFTER_BCI && state.bci != BytecodeFrame.AFTER_EXCEPTION_BCI) ||

                            state.locksSize() > 0;

            assert state.verify();

            int numLocals = state.localsSize();

            int numStack = state.stackSize();

            int numLocks = state.locksSize();

            int numValues = numLocals + numStack + numLocks;

            int numKinds = numLocals + numStack;

            JavaValue[] values = numValues == 0 ? NO_JAVA_VALUES : new JavaValue[numValues];

            JavaKind[] slotKinds = numKinds == 0 ? NO_JAVA_KINDS : new JavaKind[numKinds];

            computeLocals(state, numLocals, values, slotKinds);

            computeStack(state, numLocals, numStack, values, slotKinds);

            computeLocks(state, values);

            BytecodeFrame caller = null;

            if (state.outerFrameState() != null) {

                caller = computeFrameForState(state.outerFrameState());

            }

            if (!state.canProduceBytecodeFrame()) {

                // This typically means a snippet or intrinsic frame state made it to the backend

                String ste = state.getCode() != null ? state.getCode().asStackTraceElement(state.bci).toString() : state.toString();

                throw new GraalError("Frame state for %s cannot be converted to a BytecodeFrame since the frame state's code is " +

                                "not the same as the frame state method's code", ste);

            }

            return new BytecodeFrame(caller, state.getMethod(), state.bci, state.rethrowException(), state.duringCall(), values, slotKinds, numLocals, numStack, numLocks);

        } catch (GraalError e) {

            throw e.addContext("FrameState: ", state);

        }

    }

    protected void computeLocals(FrameState state, int numLocals, JavaValue[] values, JavaKind[] slotKinds) {

        for (int i = 0; i < numLocals; i++) {

            ValueNode local = state.localAt(i);

            values[i] = toJavaValue(local);

            slotKinds[i] = toSlotKind(local);

        }

    }

    protected void computeStack(FrameState state, int numLocals, int numStack, JavaValue[] values, JavaKind[] slotKinds) {

        for (int i = 0; i < numStack; i++) {

            ValueNode stack = state.stackAt(i);

            values[numLocals + i] = toJavaValue(stack);

            slotKinds[numLocals + i] = toSlotKind(stack);

        }

    }

    protected void computeLocks(FrameState state, JavaValue[] values) {

        for (int i = 0; i < state.locksSize(); i++) {

            values[state.localsSize() + state.stackSize() + i] = computeLockValue(state, i);

        }

    }

    protected JavaValue computeLockValue(FrameState state, int i) {

        return toJavaValue(state.lockAt(i));

    }

    private static final CounterKey STATE_VIRTUAL_OBJECTS = DebugContext.counter("StateVirtualObjects");

    private static final CounterKey STATE_ILLEGALS = DebugContext.counter("StateIllegals");

    private static final CounterKey STATE_VARIABLES = DebugContext.counter("StateVariables");

    private static final CounterKey STATE_CONSTANTS = DebugContext.counter("StateConstants");

    private static JavaKind toSlotKind(ValueNode value) {

        if (value == null) {

            return JavaKind.Illegal;

        } else {

            return value.getStackKind();

        }

    }

    protected JavaValue toJavaValue(ValueNode value) {

        try {

            if (value instanceof VirtualObjectNode) {

                VirtualObjectNode obj = (VirtualObjectNode) value;

                EscapeObjectState state = objectStates.get(obj);

                if (state == null && obj.entryCount() > 0) {

                    // null states occur for objects with 0 fields

                    throw new GraalError("no mapping found for virtual object %s", obj);

                }

                if (state instanceof MaterializedObjectState) {

                    return toJavaValue(((MaterializedObjectState) state).materializedValue());

                } else {

                    assert obj.entryCount() == 0 || state instanceof VirtualObjectState;

                    VirtualObject vobject = virtualObjects.get(obj);

                    if (vobject == null) {

                        boolean isAutoBox = obj instanceof VirtualBoxingNode;

                        vobject = GraalServices.createVirtualObject(obj.type(), virtualObjects.size(), isAutoBox);

                        virtualObjects.put(obj, vobject);

                        pendingVirtualObjects.add(obj);

                    }

                    STATE_VIRTUAL_OBJECTS.increment(debug);

                    return vobject;

                }

            } else {

                // Remove proxies from constants so the constant can be directly embedded.

                ValueNode unproxied = GraphUtil.unproxify(value);

                if (unproxied instanceof ConstantNode) {

                    STATE_CONSTANTS.increment(debug);

                    return unproxied.asJavaConstant();

                } else if (value != null) {

                    STATE_VARIABLES.increment(debug);

                    Value operand = nodeValueMap.operand(value);

                    if (operand instanceof ConstantValue && ((ConstantValue) operand).isJavaConstant()) {

                        return ((ConstantValue) operand).getJavaConstant();

                    } else {

                        assert operand instanceof Variable : operand + " for " + value;

                        return (JavaValue) operand;

                    }

                } else {

                    // return a dummy value because real value not needed

                    STATE_ILLEGALS.increment(debug);

                    return Value.ILLEGAL;

                }

            }

        } catch (GraalError e) {

            throw e.addContext("toValue: ", value);

        }

    }

}