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 * (a) the Software, and
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package com.oracle.graal.python.nodes.attributes;

import static com.oracle.graal.python.runtime.exception.PythonErrorType.AttributeError;

import com.oracle.graal.python.PythonLanguage;
import com.oracle.graal.python.builtins.PythonBuiltinClassType;
import com.oracle.graal.python.builtins.objects.PNone;
import com.oracle.graal.python.builtins.objects.function.BuiltinMethodDescriptor;
import com.oracle.graal.python.builtins.objects.function.BuiltinMethodDescriptors;
import com.oracle.graal.python.builtins.objects.module.ModuleBuiltins;
import com.oracle.graal.python.builtins.objects.object.ObjectBuiltins;
import com.oracle.graal.python.builtins.objects.type.PythonManagedClass;
import com.oracle.graal.python.builtins.objects.type.SpecialMethodSlot;
import com.oracle.graal.python.builtins.objects.type.TypeBuiltins;
import com.oracle.graal.python.nodes.attributes.GetAttributeNodeFactory.GetFixedAttributeNodeGen;
import com.oracle.graal.python.nodes.call.special.CallBinaryMethodNode;
import com.oracle.graal.python.nodes.call.special.LookupAndCallBinaryNode;
import com.oracle.graal.python.nodes.call.special.LookupSpecialMethodSlotNode;
import com.oracle.graal.python.nodes.expression.ExpressionNode;
import com.oracle.graal.python.nodes.frame.ReadNode;
import com.oracle.graal.python.nodes.object.GetClassNode;
import com.oracle.graal.python.nodes.object.IsBuiltinClassProfile;
import com.oracle.graal.python.nodes.statement.StatementNode;
import com.oracle.graal.python.runtime.exception.PException;
import com.oracle.truffle.api.Assumption;
import com.oracle.truffle.api.CompilerDirectives;
import com.oracle.truffle.api.CompilerDirectives.CompilationFinal;
import com.oracle.truffle.api.dsl.Cached;
import com.oracle.truffle.api.dsl.Specialization;
import com.oracle.truffle.api.frame.VirtualFrame;
import com.oracle.truffle.api.nodes.Node;
import com.oracle.truffle.api.profiles.ConditionProfile;

public final class GetAttributeNode extends ExpressionNode implements ReadNode {

    @Child private GetFixedAttributeNode getFixedAttributeNode;
    @Child private ExpressionNode objectExpression;

    @Override
    public Object execute(VirtualFrame frame) {
        return executeObject(frame, objectExpression.execute(frame));
    }

    public Object executeObject(VirtualFrame frame, Object object) {
        return getFixedAttributeNode.executeObject(frame, object);
    }

    protected GetAttributeNode(String key, ExpressionNode object) {
        getFixedAttributeNode = GetFixedAttributeNode.create(key);
        objectExpression = object;
    }

    public final String getKey() {
        return getFixedAttributeNode.key;
    }

    public static GetAttributeNode create(String key, ExpressionNode object) {
        return new GetAttributeNode(key, object);
    }

    public static GetAttributeNode create(String key) {
        return new GetAttributeNode(key, null);
    }

    @Override
    public final StatementNode makeWriteNode(ExpressionNode rhs) {
        return SetAttributeNode.create(getFixedAttributeNode.key, getObject(), rhs);
    }

    public ExpressionNode getObject() {
        return objectExpression;
    }

    abstract static class GetAttributeBaseNode extends Node {

        @Child protected LookupAndCallBinaryNode dispatchNode = LookupAndCallBinaryNode.create(SpecialMethodSlot.GetAttribute);
        @Child private IsBuiltinClassProfile isBuiltinClassProfile;

        @Child private LookupSpecialMethodSlotNode lookupGetattrNode;
        @Child private CallBinaryMethodNode callBinaryMethodNode;
        @Child private GetClassNode getClassNode;

        @CompilationFinal private ConditionProfile hasGetattrProfile;

        Object dispatchGetAttrOrRethrowObject(VirtualFrame frame, Object object, Object key, PException pe) {
            return ensureCallGetattrNode().executeObject(frame, lookupGetattrOrRethrow(frame, object, pe), object, key);
        }

        Object dispatchGetAttrOrRethrowObject(VirtualFrame frame, Object object, Object objectLazyClass, Object key, PException pe) {
            return ensureCallGetattrNode().executeObject(frame, lookupGetattrOrRethrow(frame, object, objectLazyClass, pe), object, key);
        }

        private Object lookupGetattrOrRethrow(VirtualFrame frame, Object object, PException pe) {
            return lookupGetattrOrRethrow(frame, object, getPythonClass(object), pe);
        }

        /** Lookup {@code __getattr__} or rethrow {@code pe} if it does not exist. */
        private Object lookupGetattrOrRethrow(VirtualFrame frame, Object object, Object objectLazyClass, PException pe) {
            Object getattrAttribute = ensureLookupGetattrNode().execute(frame, objectLazyClass, object);
            if (ensureHasGetattrProfile().profile(getattrAttribute == PNone.NO_VALUE)) {
                throw pe;
            }
            return getattrAttribute;
        }

        private LookupSpecialMethodSlotNode ensureLookupGetattrNode() {
            if (lookupGetattrNode == null) {
                CompilerDirectives.transferToInterpreterAndInvalidate();
                lookupGetattrNode = insert(LookupSpecialMethodSlotNode.create(SpecialMethodSlot.GetAttr));
            }
            return lookupGetattrNode;
        }

        private CallBinaryMethodNode ensureCallGetattrNode() {
            if (callBinaryMethodNode == null) {
                CompilerDirectives.transferToInterpreterAndInvalidate();
                callBinaryMethodNode = insert(CallBinaryMethodNode.create());
            }
            return callBinaryMethodNode;
        }

        private ConditionProfile ensureHasGetattrProfile() {
            if (hasGetattrProfile == null) {
                CompilerDirectives.transferToInterpreterAndInvalidate();
                hasGetattrProfile = ConditionProfile.createBinaryProfile();
            }
            return hasGetattrProfile;
        }

        protected Object getPythonClass(Object object) {
            if (getClassNode == null) {
                CompilerDirectives.transferToInterpreterAndInvalidate();
                getClassNode = insert(GetClassNode.create());
            }
            return getClassNode.execute(object);
        }

        Assumption singleContextAssumption() {
            return PythonLanguage.get(this).singleContextAssumption;
        }

        protected IsBuiltinClassProfile getErrorProfile() {
            if (isBuiltinClassProfile == null) {
                CompilerDirectives.transferToInterpreterAndInvalidate();
                isBuiltinClassProfile = insert(IsBuiltinClassProfile.create());
            }
            return isBuiltinClassProfile;
        }
    }

    public abstract static class GetFixedAttributeNode extends GetAttributeBaseNode {
        private final String key;

        public GetFixedAttributeNode(String key) {
            this.key = key;
        }

        public final String getKey() {
            return key;
        }

        public final Object executeObject(VirtualFrame frame, Object object) {
            return execute(frame, object);
        }

        public abstract Object execute(VirtualFrame frame, Object object);

        protected static boolean getAttributeIs(Object lazyClass, BuiltinMethodDescriptor expected) {
            Object slotValue = null;
            if (lazyClass instanceof PythonBuiltinClassType) {
                slotValue = SpecialMethodSlot.GetAttribute.getValue((PythonBuiltinClassType) lazyClass);
            } else if (lazyClass instanceof PythonManagedClass) {
                slotValue = SpecialMethodSlot.GetAttribute.getValue((PythonManagedClass) lazyClass);
            }
            return slotValue == expected;
        }

        protected static boolean isObjectGetAttribute(Object lazyClass) {
            return getAttributeIs(lazyClass, BuiltinMethodDescriptors.OBJ_GET_ATTRIBUTE);
        }

        protected static boolean isModuleGetAttribute(Object lazyClass) {
            return getAttributeIs(lazyClass, BuiltinMethodDescriptors.MODULE_GET_ATTRIBUTE);
        }

        protected static boolean isTypeGetAttribute(Object lazyClass) {
            return getAttributeIs(lazyClass, BuiltinMethodDescriptors.TYPE_GET_ATTRIBUTE);
        }

        /*
         * Here we have fast-paths for the most common values found in the __getattribute__ slot but
         * only for multi-context mode. The caching we can do in the generic lookup attribute
         * machinery (i.e., LookupCallableSlotInMRONode) in single context case seems to perform as
         * good as this fast-path (both in interpreter and in compiled code), so no point in using
         * it in single context mode.
         */

        @Specialization(assumptions = "singleContextAssumption()")
        final Object doSingleContext(VirtualFrame frame, Object object) {
            try {
                return dispatchNode.executeObject(frame, object, key);
            } catch (PException pe) {
                pe.expect(AttributeError, getErrorProfile());
                return dispatchGetAttrOrRethrowObject(frame, object, getPythonClass(object), key, pe);
            }
        }

        @Specialization(replaces = "doSingleContext", guards = "isObjectGetAttribute(getPythonClass(object))")
        final Object doBuiltinObject(VirtualFrame frame, Object object,
                        @Cached ObjectBuiltins.GetAttributeNode getAttributeNode) {
            try {
                return getAttributeNode.execute(frame, object, key);
            } catch (PException pe) {
                pe.expect(AttributeError, getErrorProfile());
                return dispatchGetAttrOrRethrowObject(frame, object, key, pe);
            }
        }

        @Specialization(replaces = "doSingleContext", guards = "isTypeGetAttribute(getPythonClass(object))")
        final Object doBuiltinType(VirtualFrame frame, Object object,
                        @Cached TypeBuiltins.GetattributeNode getAttributeNode) {
            try {
                return getAttributeNode.execute(frame, object, key);
            } catch (PException pe) {
                pe.expect(AttributeError, getErrorProfile());
                return dispatchGetAttrOrRethrowObject(frame, object, key, pe);
            }
        }

        @Specialization(replaces = "doSingleContext", guards = "isModuleGetAttribute(getPythonClass(object))")
        final Object doBuiltinModule(VirtualFrame frame, Object object,
                        @Cached ModuleBuiltins.ModuleGetattritbuteNode getAttributeNode) {
            try {
                return getAttributeNode.execute(frame, object, key);
            } catch (PException pe) {
                pe.expect(AttributeError, getErrorProfile());
                return dispatchGetAttrOrRethrowObject(frame, object, key, pe);
            }
        }

        @Specialization(replaces = {"doBuiltinObject", "doBuiltinType", "doBuiltinModule"})
        final Object doGeneric(VirtualFrame frame, Object object) {
            try {
                return dispatchNode.executeObject(frame, object, key);
            } catch (PException pe) {
                pe.expect(AttributeError, getErrorProfile());
                return dispatchGetAttrOrRethrowObject(frame, object, getPythonClass(object), key, pe);
            }
        }

        public static GetFixedAttributeNode create(String key) {
            return GetFixedAttributeNodeGen.create(key);
        }
    }

    public static final class GetAnyAttributeNode extends GetAttributeBaseNode {

        public Object executeObject(VirtualFrame frame, Object object, Object key) {
            try {
                return dispatchNode.executeObject(frame, object, key);
            } catch (PException pe) {
                pe.expect(AttributeError, getErrorProfile());
                return dispatchGetAttrOrRethrowObject(frame, object, key, pe);
            }
        }

        public static GetAnyAttributeNode create() {
            return new GetAnyAttributeNode();
        }
    }
}
