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 * (b) any piece of software and/or hardware listed in the lrgrwrks.txt file if
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package com.oracle.truffle.js.nodes.instrumentation;

import java.util.ArrayList;
import java.util.List;
import java.util.Set;

import com.oracle.truffle.api.frame.FrameDescriptor;
import com.oracle.truffle.api.frame.FrameSlot;
import com.oracle.truffle.api.frame.VirtualFrame;
import com.oracle.truffle.api.instrumentation.Tag;
import com.oracle.truffle.api.nodes.ExplodeLoop;
import com.oracle.truffle.api.source.SourceSection;
import com.oracle.truffle.js.nodes.JavaScriptNode;
import com.oracle.truffle.js.nodes.function.BlockScopeNode.FrameBlockScopeNode;
import com.oracle.truffle.js.nodes.function.FunctionBodyNode;
import com.oracle.truffle.js.runtime.JSFrameUtil;
import com.oracle.truffle.js.runtime.objects.Undefined;

public final class DeclareTagProvider {

    public static JavaScriptNode createMaterializedFunctionBodyNode(JavaScriptNode body, SourceSection sourceSection, FrameDescriptor frameDescriptor) {
        return new MaterializedFunctionBodyNode(body, sourceSection, frameDescriptor);
    }

    public static JavaScriptNode createMaterializedBlockNode(JavaScriptNode block, FrameDescriptor frameDescriptor, FrameSlot parentSlot, SourceSection sourceSection) {
        return new MaterializedFrameBlockScopeNode(block, frameDescriptor, parentSlot, sourceSection);
    }

    public static boolean isMaterializedFrameProvider(JavaScriptNode node) {
        return node instanceof MaterializedFrameBlockScopeNode || node instanceof MaterializedFunctionBodyNode;
    }

    public static NodeObjectDescriptor createDeclareNodeObject(Object name, Object type) {
        NodeObjectDescriptor descriptor = JSTags.createNodeObjectDescriptor();
        descriptor.addProperty(JSTags.DeclareTag.NAME, name);
        descriptor.addProperty(JSTags.DeclareTag.TYPE, type);
        return descriptor;
    }

    private DeclareTagProvider() {
    }

    private static JavaScriptNode[] initDeclarations(FrameDescriptor frameDescriptor, SourceSection sourceSection) {
        assert sourceSection != null;
        if (frameDescriptor != null) {
            List<FrameSlot> slots = new ArrayList<>();
            for (FrameSlot slot : frameDescriptor.getSlots()) {
                if (!JSFrameUtil.isInternal(slot) && !JSFrameUtil.isHoistable(slot)) {
                    slots.add(slot);
                }
            }
            JavaScriptNode[] declarations = new JavaScriptNode[slots.size()];
            for (int i = 0; i < slots.size(); i++) {
                declarations[i] = new DeclareProviderNode(slots.get(i));
                declarations[i].setSourceSection(sourceSection);
            }
            return declarations;
        } else {
            return new JavaScriptNode[0];
        }
    }

    private static class MaterializedFrameBlockScopeNode extends FrameBlockScopeNode {

        @Children private JavaScriptNode[] declarations;

        protected MaterializedFrameBlockScopeNode(JavaScriptNode block, FrameDescriptor frameDescriptor, FrameSlot parentSlot, SourceSection sourceSection) {
            super(block, frameDescriptor, parentSlot);
            this.declarations = initDeclarations(frameDescriptor, sourceSection);
        }

        @ExplodeLoop
        private void executeDeclarations(VirtualFrame frame) {
            for (JavaScriptNode declaration : declarations) {
                declaration.execute(frame);
            }
        }

        @Override
        public Object execute(VirtualFrame frame) {
            executeDeclarations(frame);
            return super.execute(frame);
        }

        @Override
        public void executeVoid(VirtualFrame frame) {
            executeDeclarations(frame);
            super.executeVoid(frame);
        }

        @Override
        protected JavaScriptNode copyUninitialized(Set<Class<? extends Tag>> materializedTags) {
            return new MaterializedFrameBlockScopeNode(cloneUninitialized(block, materializedTags), frameDescriptor, parentSlot, getSourceSection());
        }
    }

    private static class MaterializedFunctionBodyNode extends FunctionBodyNode {

        @Children private JavaScriptNode[] declarations;

        private final FrameDescriptor frameDescriptor;

        protected MaterializedFunctionBodyNode(JavaScriptNode body, SourceSection sourceSection, FrameDescriptor frameDescriptor) {
            super(body);
            this.frameDescriptor = frameDescriptor;
            this.declarations = initDeclarations(frameDescriptor, sourceSection);
        }

        @ExplodeLoop
        @Override
        public Object execute(VirtualFrame frame) {
            for (JavaScriptNode declaration : declarations) {
                declaration.execute(frame);
            }
            return super.execute(frame);
        }

        @Override
        protected JavaScriptNode copyUninitialized(Set<Class<? extends Tag>> materializedTags) {
            return new MaterializedFunctionBodyNode(cloneUninitialized(getBody(), materializedTags), getSourceSection(), frameDescriptor);
        }
    }

    private static class DeclareProviderNode extends JavaScriptNode {

        private final FrameSlot slot;

        DeclareProviderNode(FrameSlot slot) {
            this.slot = slot;
        }

        @Override
        public Object execute(VirtualFrame frame) {
            // Ignored
            return Undefined.instance;
        }

        @Override
        public boolean hasTag(Class<? extends Tag> tag) {
            if (tag == JSTags.DeclareTag.class) {
                return true;
            } else {
                return super.hasTag(tag);
            }
        }

        @Override
        public boolean isInstrumentable() {
            return true;
        }

        @Override
        public Object getNodeObject() {
            String type;
            if (JSFrameUtil.isConst(slot)) {
                type = "const";
            } else if (JSFrameUtil.isLet(slot)) {
                type = "let";
            } else {
                type = "var";
            }
            return createDeclareNodeObject(slot.getIdentifier(), type);
        }

        @Override
        protected JavaScriptNode copyUninitialized(Set<Class<? extends Tag>> materializedTags) {
            return new DeclareProviderNode(slot);
        }
    }
}