/*
 * Copyright (c) 2017, 2020, Oracle and/or its affiliates.
 *
 * All rights reserved.
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 * permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, this list of
 * conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice, this list of
 * conditions and the following disclaimer in the documentation and/or other materials provided
 * with the distribution.
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 * 3. Neither the name of the copyright holder nor the names of its contributors may be used to
 * endorse or promote products derived from this software without specific prior written
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 *
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 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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package com.oracle.truffle.llvm.runtime.nodes.func;

import com.oracle.truffle.api.CompilerAsserts;
import com.oracle.truffle.api.CompilerDirectives;
import com.oracle.truffle.api.CompilerDirectives.CompilationFinal;
import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
import com.oracle.truffle.api.TruffleLanguage.ContextReference;
import com.oracle.truffle.api.dsl.Cached;
import com.oracle.truffle.api.dsl.CachedContext;
import com.oracle.truffle.api.dsl.Specialization;
import com.oracle.truffle.api.interop.InteropException;
import com.oracle.truffle.api.interop.InteropLibrary;
import com.oracle.truffle.api.library.CachedLibrary;
import com.oracle.truffle.api.nodes.DirectCallNode;
import com.oracle.truffle.api.nodes.ExplodeLoop;
import com.oracle.truffle.api.nodes.IndirectCallNode;
import com.oracle.truffle.api.source.Source;
import com.oracle.truffle.llvm.runtime.CommonNodeFactory;
import com.oracle.truffle.llvm.runtime.ContextExtension;
import com.oracle.truffle.llvm.runtime.LLVMContext;
import com.oracle.truffle.llvm.runtime.LLVMFunctionCode;
import com.oracle.truffle.llvm.runtime.LLVMFunctionCode.ResolveFunctionNode;
import com.oracle.truffle.llvm.runtime.LLVMFunctionDescriptor;
import com.oracle.truffle.llvm.runtime.LLVMLanguage;
import com.oracle.truffle.llvm.runtime.NativeContextExtension;
import com.oracle.truffle.llvm.runtime.NativeContextExtension.UnsupportedNativeTypeException;
import com.oracle.truffle.llvm.runtime.except.LLVMNativePointerException;
import com.oracle.truffle.llvm.runtime.except.LLVMPolyglotException;
import com.oracle.truffle.llvm.runtime.interop.LLVMDataEscapeNode;
import com.oracle.truffle.llvm.runtime.interop.access.LLVMInteropType;
import com.oracle.truffle.llvm.runtime.interop.convert.ForeignToLLVM;
import com.oracle.truffle.llvm.runtime.interop.nfi.LLVMNativeConvertNode;
import com.oracle.truffle.llvm.runtime.library.internal.LLVMAsForeignLibrary;
import com.oracle.truffle.llvm.runtime.nodes.api.LLVMNode;
import com.oracle.truffle.llvm.runtime.nodes.func.LLVMDispatchNodeGen.LLVMLookupDispatchForeignNodeGen;
import com.oracle.truffle.llvm.runtime.pointer.LLVMNativePointer;
import com.oracle.truffle.llvm.runtime.types.FunctionType;
import com.oracle.truffle.llvm.runtime.types.VoidType;
import com.oracle.truffle.llvm.spi.NativeTypeLibrary;

public abstract class LLVMDispatchNode extends LLVMNode {

    protected static final int INLINE_CACHE_SIZE = 5;

    protected final FunctionType type;

    @CompilationFinal private Source signatureSource;
    @CompilationFinal private ContextExtension.Key<NativeContextExtension> nativeCtxExtKey;

    protected LLVMDispatchNode(FunctionType type) {
        this.type = type;
    }

    @Override
    public String toString() {
        return getShortString("type", "signature");
    }

    boolean haveNativeCtxExt() {
        CompilerAsserts.neverPartOfCompilation();
        return LLVMLanguage.getLanguage().lookupContextExtension(NativeContextExtension.class) != null;
    }

    NativeContextExtension getNativeCtxExt(ContextReference<LLVMContext> ctxRef) {
        if (nativeCtxExtKey == null) {
            CompilerDirectives.transferToInterpreterAndInvalidate();
            nativeCtxExtKey = ctxRef.get().getLanguage().lookupContextExtension(NativeContextExtension.class);
        }
        return nativeCtxExtKey.get(ctxRef.get());
    }

    private Source getSignatureSource(ContextReference<LLVMContext> ctxRef) {
        if (signatureSource == null) {
            CompilerDirectives.transferToInterpreterAndInvalidate();
            try {
                this.signatureSource = getNativeCtxExt(ctxRef).getNativeSignatureSourceSkipStackArg(type);
            } catch (UnsupportedNativeTypeException ex) {
                CompilerDirectives.transferToInterpreter();
                throw new AssertionError(ex);
            }
        }
        return signatureSource;
    }

    
function is expected to be either LLVMFunctionDescriptor, LLVMNativePointer or a foreign object, and it needs to be resolved using LLVMLookupDispatchTargetNode. /**
     * {@code function} is expected to be either {@link LLVMFunctionDescriptor},
     * {@link LLVMNativePointer} or a foreign object, and it needs to be resolved using
     * {@link LLVMLookupDispatchTargetNode}.
     */
    public abstract Object executeDispatch(Object function, Object[] arguments);

    /*
     * Function is defined in the user program (available as LLVM IR) or the function is an
     * intrinsic.
     */

    protected DirectCallNode createCallNode(LLVMFunctionCode code) {
        if (code.isLLVMIRFunction()) {
            return DirectCallNode.create(code.getLLVMIRFunctionSlowPath());
        } else if (code.isIntrinsicFunctionSlowPath()) {
            return DirectCallNode.create(code.getIntrinsicSlowPath().cachedCallTarget(type));
        } else {
            return null;
        }
    }

    @Specialization(limit = "INLINE_CACHE_SIZE", guards = {"code == cachedFunctionCode"})
    protected static Object doDirectCodeFast(@SuppressWarnings("unused") LLVMFunctionCode code, Object[] arguments,
                    @Cached("code") @SuppressWarnings("unused") LLVMFunctionCode cachedFunctionCode,
                    @Cached("createCallNode(cachedFunctionCode)") DirectCallNode callNode) {
        assert callNode != null : "inconsistent behavior of LLVMLookupDispatchTargetSymbolNode";
        return callNode.call(arguments);
    }

    @Specialization(limit = "INLINE_CACHE_SIZE", replaces = "doDirectCodeFast", guards = {"descriptor == cachedDescriptor", "callNode != null"}, assumptions = "singleContextAssumption()")
    protected static Object doDirectFunction(@SuppressWarnings("unused") LLVMFunctionDescriptor descriptor, Object[] arguments,
                    @Cached("descriptor") @SuppressWarnings("unused") LLVMFunctionDescriptor cachedDescriptor,
                    @Cached("cachedDescriptor.getFunctionCode()") @SuppressWarnings("unused") LLVMFunctionCode cachedFunctionCode,
                    @Cached("createCallNode(cachedFunctionCode)") DirectCallNode callNode) {
        return callNode.call(arguments);
    }

    @Specialization(limit = "INLINE_CACHE_SIZE", replaces = {"doDirectCodeFast", "doDirectFunction"}, guards = {"descriptor.getFunctionCode() == cachedFunctionCode", "callNode != null"})
    protected static Object doDirectCode(@SuppressWarnings("unused") LLVMFunctionDescriptor descriptor, Object[] arguments,
                    @Cached("descriptor.getFunctionCode()") @SuppressWarnings("unused") LLVMFunctionCode cachedFunctionCode,
                    @Cached("createCallNode(cachedFunctionCode)") DirectCallNode callNode) {
        return callNode.call(arguments);
    }

    @Specialization(replaces = {"doDirectCodeFast", "doDirectCode"}, guards = "descriptor.getFunctionCode().isLLVMIRFunction()")
    protected static Object doIndirect(LLVMFunctionDescriptor descriptor, Object[] arguments,
                    @Cached ResolveFunctionNode resolve,
                    @Cached("create()") IndirectCallNode callNode) {
        return callNode.call(descriptor.getFunctionCode().getLLVMIRFunction(resolve), arguments);
    }

    @Specialization(replaces = {"doDirectCodeFast", "doDirectCode"}, guards = "descriptor.getFunctionCode().isIntrinsicFunction(resolve)")
    protected Object doIndirectIntrinsic(LLVMFunctionDescriptor descriptor, Object[] arguments,
                    @Cached ResolveFunctionNode resolve,
                    @Cached("create()") IndirectCallNode callNode) {
        return callNode.call(descriptor.getFunctionCode().getIntrinsic(resolve).cachedCallTarget(type), arguments);
    }

    /*
     * Function is not defined in the user program (not available as LLVM IR). No intrinsic
     * available. We do a native call.
     */

    @Specialization(limit = "INLINE_CACHE_SIZE", guards = {"descriptor == cachedDescriptor", "cachedFunctionCode.isNativeFunctionSlowPath()",
                    "haveNativeCtxExt()"}, assumptions = "singleContextAssumption()")
    protected Object doCachedNativeFunction(@SuppressWarnings("unused") LLVMFunctionDescriptor descriptor,
                    Object[] arguments,
                    @Cached("descriptor") LLVMFunctionDescriptor cachedDescriptor,
                    @Cached("cachedDescriptor.getFunctionCode()") @SuppressWarnings("unused") LLVMFunctionCode cachedFunctionCode,
                    @Cached("createToNativeNodes()") LLVMNativeConvertNode[] toNative,
                    @Cached("createFromNativeNode()") LLVMNativeConvertNode fromNative,
                    @CachedContext(LLVMLanguage.class) ContextReference<LLVMContext> context,
                    @Cached("bindSymbol(cachedFunctionCode, context)") Object cachedBoundFunction,
                    @CachedLibrary("cachedBoundFunction") InteropLibrary nativeCall,
                    @Cached("nativeCallStatisticsEnabled(context)") boolean statistics) {

        Object[] nativeArgs = prepareNativeArguments(arguments, toNative);
        Object returnValue;
        returnValue = LLVMNativeCallUtils.callNativeFunction(statistics, context, nativeCall, cachedBoundFunction, nativeArgs, cachedDescriptor);
        return fromNative.executeConvert(returnValue);
    }

    @Specialization(replaces = "doCachedNativeFunction", guards = {"descriptor.getFunctionCode() == cachedFunctionCode",
                    "cachedFunctionCode.isNativeFunctionSlowPath()"}, assumptions = "singleContextAssumption()")
    protected Object doCachedNativeCode(@SuppressWarnings("unused") LLVMFunctionDescriptor descriptor,
                    Object[] arguments,
                    @Cached("descriptor.getFunctionCode()") @SuppressWarnings("unused") LLVMFunctionCode cachedFunctionCode,
                    @Cached("createToNativeNodes()") LLVMNativeConvertNode[] toNative,
                    @Cached("createFromNativeNode()") LLVMNativeConvertNode fromNative,
                    @CachedContext(LLVMLanguage.class) ContextReference<LLVMContext> context,
                    @Cached("bindSymbol(cachedFunctionCode, context)") Object cachedBoundFunction,
                    @CachedLibrary("cachedBoundFunction") InteropLibrary nativeCall,
                    @Cached("nativeCallStatisticsEnabled(context)") boolean statistics) {

        Object[] nativeArgs = prepareNativeArguments(arguments, toNative);
        Object returnValue;
        returnValue = LLVMNativeCallUtils.callNativeFunction(statistics, context, nativeCall, cachedBoundFunction, nativeArgs, descriptor);
        return fromNative.executeConvert(returnValue);
    }

    @TruffleBoundary
    private static Object doBind(NativeContextExtension ctxExt, LLVMFunctionCode functionCode, Source signatureSource) {
        return ctxExt.bindSignature(functionCode, signatureSource);
    }

    protected Object bindSymbol(LLVMFunctionCode functionCode, ContextReference<LLVMContext> ctxRef) {
        assert functionCode.getNativeFunctionSlowPath() != null : functionCode.getLLVMFunction().getName();
        return doBind(getNativeCtxExt(ctxRef), functionCode, getSignatureSource(ctxRef));
    }

    @Specialization(replaces = "doCachedNativeCode", guards = {"descriptor.getFunctionCode().isNativeFunction(resolve)", "haveNativeCtxExt()"})
    protected Object doNative(LLVMFunctionDescriptor descriptor, Object[] arguments,
                    @Cached("createToNativeNodes()") LLVMNativeConvertNode[] toNative,
                    @Cached("createFromNativeNode()") LLVMNativeConvertNode fromNative,
                    @CachedLibrary(limit = "3") InteropLibrary nativeCall,
                    @CachedContext(LLVMLanguage.class) ContextReference<LLVMContext> context,
                    @Cached @SuppressWarnings("unused") ResolveFunctionNode resolve,
                    @Cached("nativeCallStatisticsEnabled(context)") boolean statistics) {

        Object[] nativeArgs = prepareNativeArguments(arguments, toNative);
        Object boundSymbol = bindSymbol(descriptor.getFunctionCode(), context);
        Object returnValue;
        returnValue = LLVMNativeCallUtils.callNativeFunction(statistics, context, nativeCall, boundSymbol, nativeArgs, descriptor);
        return fromNative.executeConvert(returnValue);
    }

    @ExplodeLoop
    private static Object[] prepareNativeArguments(Object[] arguments, LLVMNativeConvertNode[] toNative) {
        Object[] nativeArgs = new Object[arguments.length - LLVMCallNode.USER_ARGUMENT_OFFSET];
        for (int i = LLVMCallNode.USER_ARGUMENT_OFFSET; i < arguments.length; i++) {
            nativeArgs[i - LLVMCallNode.USER_ARGUMENT_OFFSET] = toNative[i - LLVMCallNode.USER_ARGUMENT_OFFSET].executeConvert(arguments[i]);
        }
        return nativeArgs;
    }

    protected LLVMNativeConvertNode[] createToNativeNodes() {
        LLVMNativeConvertNode[] ret = new LLVMNativeConvertNode[type.getNumberOfArguments() - LLVMCallNode.USER_ARGUMENT_OFFSET];
        for (int i = LLVMCallNode.USER_ARGUMENT_OFFSET; i < type.getNumberOfArguments(); i++) {
            ret[i - LLVMCallNode.USER_ARGUMENT_OFFSET] = LLVMNativeConvertNode.createToNative(type.getArgumentType(i));
        }
        return ret;
    }

    protected LLVMNativeConvertNode createFromNativeNode() {
        CompilerAsserts.neverPartOfCompilation();
        return LLVMNativeConvertNode.createFromNative(type.getReturnType());
    }

    @Specialization(guards = {"foreigns.isForeign(receiver)"})
    protected Object doForeign(Object receiver, Object[] arguments,
                    @CachedLibrary(limit = "3") LLVMAsForeignLibrary foreigns,
                    @CachedLibrary(limit = "3") NativeTypeLibrary natives,
                    @Cached("create(type)") LLVMLookupDispatchForeignNode lookupDispatchForeignNode) {
        return lookupDispatchForeignNode.execute(foreigns.asForeign(receiver), natives.getNativeType(receiver), arguments);
    }

    @Specialization(guards = "haveNativeCtxExt()")
    protected static Object doNativeFunction(LLVMNativePointer pointer, Object[] arguments,
                    @Cached("createCachedNativeDispatch()") LLVMNativeDispatchNode dispatchNode) {
        try {
            return dispatchNode.executeDispatch(pointer, arguments);
        } catch (IllegalStateException e) {
            CompilerDirectives.transferToInterpreter();
            throw new LLVMNativePointerException(dispatchNode, "Invalid native function pointer", e);
        }
    }

    @Specialization(guards = "!haveNativeCtxExt()")
    protected Object doInvalidNativeFunction(@SuppressWarnings("unused") LLVMNativePointer pointer, @SuppressWarnings("unused") Object[] arguments) {
        throw new LLVMNativePointerException(this, "Invalid native function pointer", null);
    }

    protected LLVMNativeDispatchNode createCachedNativeDispatch() {
        return LLVMNativeDispatchNodeGen.create(type, getSignatureSource(lookupContextReference(LLVMLanguage.class)));
    }

    abstract static class LLVMLookupDispatchForeignNode extends LLVMNode {

        private final boolean isVoidReturn;
        private final int argumentCount;
        private final FunctionType type;

        LLVMLookupDispatchForeignNode(FunctionType type) {
            this.type = type;
            this.isVoidReturn = type.getReturnType() instanceof VoidType;
            this.argumentCount = type.getNumberOfArguments();
        }

        abstract Object execute(Object function, Object interopType, Object[] arguments);

        @Specialization(guards = "functionType == cachedType", limit = "5")
        protected Object doCachedType(Object function, @SuppressWarnings("unused") LLVMInteropType.Function functionType, Object[] arguments,
                        @Cached("functionType") LLVMInteropType.Function cachedType,
                        @CachedLibrary("function") InteropLibrary crossLanguageCall,
                        @Cached("createLLVMDataEscapeNodes()") LLVMDataEscapeNode[] dataEscapeNodes,
                        @Cached("createToLLVMNode()") ForeignToLLVM toLLVMNode) {
            return doGeneric(function, cachedType, arguments, crossLanguageCall, dataEscapeNodes, toLLVMNode);
        }

        @Specialization(replaces = "doCachedType", limit = "0")
        protected Object doGeneric(Object function, LLVMInteropType.Function functionType, Object[] arguments,
                        @CachedLibrary("function") InteropLibrary crossLanguageCall,
                        @Cached("createLLVMDataEscapeNodes()") LLVMDataEscapeNode[] dataEscapeNodes,
                        @Cached("createToLLVMNode()") ForeignToLLVM toLLVMNode) {
            try {
                Object[] args = getForeignArguments(dataEscapeNodes, arguments, functionType);
                Object ret;
                ret = crossLanguageCall.execute(function, args);
                if (!isVoidReturn && functionType != null) {
                    LLVMInteropType retType = functionType.getReturnType();
                    if (retType instanceof LLVMInteropType.Value) {
                        return toLLVMNode.executeWithType(ret, ((LLVMInteropType.Value) retType).baseType);
                    } else {
                        CompilerDirectives.transferToInterpreter();
                        throw new LLVMPolyglotException(this, "Cannot call polyglot function with structured return type.");
                    }
                } else {
                    return toLLVMNode.executeWithTarget(ret);
                }
            } catch (InteropException e) {
                throw CompilerDirectives.shouldNotReachHere(e);
            }
        }

        boolean isNotFunctionType(Object functionType) {
            return !(functionType instanceof LLVMInteropType.Function);
        }

        @Specialization(guards = "isNotFunctionType(functionType)", limit = "5")
        protected Object doUnknownType(Object function, @SuppressWarnings("unused") Object functionType, Object[] arguments,
                        @CachedLibrary("function") InteropLibrary crossLanguageCall,
                        @Cached("createLLVMDataEscapeNodes()") LLVMDataEscapeNode[] dataEscapeNodes,
                        @Cached("createToLLVMNode()") ForeignToLLVM toLLVMNode) {
            return doGeneric(function, null, arguments, crossLanguageCall, dataEscapeNodes, toLLVMNode);
        }

        @ExplodeLoop
        private Object[] getForeignArguments(LLVMDataEscapeNode[] dataEscapeNodes, Object[] arguments, LLVMInteropType.Function functionType) {
            assert arguments.length == argumentCount;
            Object[] args = new Object[dataEscapeNodes.length];
            int i = 0;
            if (functionType != null) {
                assert arguments.length == functionType.getNumberOfParameters() + LLVMCallNode.USER_ARGUMENT_OFFSET;
                for (; i < functionType.getNumberOfParameters(); i++) {
                    LLVMInteropType argType = functionType.getParameter(i);
                    if (argType instanceof LLVMInteropType.Value) {
                        LLVMInteropType.Structured baseType = ((LLVMInteropType.Value) argType).baseType;
                        args[i] = dataEscapeNodes[i].executeWithType(arguments[i + LLVMCallNode.USER_ARGUMENT_OFFSET], baseType);
                    } else {
                        CompilerDirectives.transferToInterpreter();
                        throw new LLVMPolyglotException(this, "Cannot call polyglot function with structured argument type.");
                    }
                }
            }

            // handle remaining arguments (varargs or functionType == null)
            for (; i < args.length; i++) {
                args[i] = dataEscapeNodes[i].executeWithTarget(arguments[i + LLVMCallNode.USER_ARGUMENT_OFFSET]);
            }
            return args;
        }

        protected ForeignToLLVM createToLLVMNode() {
            return CommonNodeFactory.createForeignToLLVM(ForeignToLLVM.convert(type.getReturnType()));
        }

        protected LLVMDataEscapeNode[] createLLVMDataEscapeNodes() {
            CompilerAsserts.neverPartOfCompilation();
            LLVMDataEscapeNode[] args = new LLVMDataEscapeNode[type.getNumberOfArguments() - LLVMCallNode.USER_ARGUMENT_OFFSET];
            for (int i = 0; i < args.length; i++) {
                args[i] = LLVMDataEscapeNode.create(type.getArgumentType(i + LLVMCallNode.USER_ARGUMENT_OFFSET));
            }
            return args;
        }

        public static LLVMLookupDispatchForeignNode create(FunctionType type) {
            return LLVMLookupDispatchForeignNodeGen.create(type);
        }
    }
}