Ejemplo n.º 1
0
        private bool IsStubRequired()
        {
            MethodDesc method = _methodData.TargetMethod;

            Debug.Assert(method.IsPInvoke || method is DelegateMarshallingMethodThunk);

            if (method is DelegateMarshallingMethodThunk)
            {
                return(true);
            }

            if (MarshalHelpers.UseLazyResolution(method, _methodData.ImportMetadata.Module, _methodData.PInvokeILEmitterConfiguration))
            {
                return(true);
            }
            if ((_methodData.ImportMetadata.Attributes & PInvokeAttributes.SetLastError) == PInvokeAttributes.SetLastError)
            {
                return(true);
            }

            for (int i = 0; i < _marshallers.Length; i++)
            {
                if (_marshallers[i].IsMarshallingRequired())
                {
                    return(true);
                }
            }
            return(false);
        }
Ejemplo n.º 2
0
        private bool IsStubRequired()
        {
            Debug.Assert(_targetMethod.IsPInvoke || _targetMethod is DelegateMarshallingMethodThunk);

            if (_targetMethod is DelegateMarshallingMethodThunk)
            {
                return(true);
            }

            if (MarshalHelpers.UseLazyResolution(_targetMethod, _importMetadata.Module,
                                                 _pInvokeILEmitterConfiguration))
            {
                return(true);
            }
            if (_flags.SetLastError)
            {
                return(true);
            }

            for (int i = 0; i < _marshallers.Length; i++)
            {
                if (_marshallers[i].IsMarshallingRequired())
                {
                    return(true);
                }
            }
            return(false);
        }
Ejemplo n.º 3
0
        private void EmitPInvokeCall(PInvokeILCodeStreams ilCodeStreams)
        {
            ILEmitter         emitter                 = ilCodeStreams.Emitter;
            ILCodeStream      fnptrLoadStream         = ilCodeStreams.FunctionPointerLoadStream;
            ILCodeStream      callsiteSetupCodeStream = ilCodeStreams.CallsiteSetupCodeStream;
            TypeSystemContext context                 = _targetMethod.Context;

            TypeDesc nativeReturnType = _marshallers[0].NativeParameterType;

            TypeDesc[] nativeParameterTypes = new TypeDesc[_marshallers.Length - 1];

            // if the SetLastError flag is set in DllImport, clear the error code before doing P/Invoke
            if (_flags.SetLastError)
            {
                callsiteSetupCodeStream.Emit(ILOpcode.call, emitter.NewToken(
                                                 InteropTypes.GetPInvokeMarshal(context).GetKnownMethod("ClearLastWin32Error", null)));
            }

            for (int i = 1; i < _marshallers.Length; i++)
            {
                nativeParameterTypes[i - 1] = _marshallers[i].NativeParameterType;
            }

            if (MarshalHelpers.UseLazyResolution(_targetMethod,
                                                 _importMetadata.Module,
                                                 _pInvokeILEmitterConfiguration))
            {
                MetadataType lazyHelperType   = context.GetHelperType("InteropHelpers");
                FieldDesc    lazyDispatchCell = _interopStateManager.GetPInvokeLazyFixupField(_targetMethod);

                fnptrLoadStream.Emit(ILOpcode.ldsflda, emitter.NewToken(lazyDispatchCell));
                fnptrLoadStream.Emit(ILOpcode.call, emitter.NewToken(lazyHelperType
                                                                     .GetKnownMethod("ResolvePInvoke", null)));

                MethodSignatureFlags unmanagedCallConv = _flags.UnmanagedCallingConvention;

                MethodSignature nativeSig = new MethodSignature(
                    _targetMethod.Signature.Flags | unmanagedCallConv, 0, nativeReturnType,
                    nativeParameterTypes);

                ILLocalVariable vNativeFunctionPointer = emitter.NewLocal(context
                                                                          .GetWellKnownType(WellKnownType.IntPtr));

                fnptrLoadStream.EmitStLoc(vNativeFunctionPointer);
                callsiteSetupCodeStream.EmitLdLoc(vNativeFunctionPointer);
                callsiteSetupCodeStream.Emit(ILOpcode.calli, emitter.NewToken(nativeSig));
            }
            else
            {
                // Eager call
                MethodSignature nativeSig = new MethodSignature(
                    _targetMethod.Signature.Flags, 0, nativeReturnType, nativeParameterTypes);

                MethodDesc nativeMethod =
                    new PInvokeTargetNativeMethod(_targetMethod, nativeSig);

                callsiteSetupCodeStream.Emit(ILOpcode.call, emitter.NewToken(nativeMethod));
            }

            // if the SetLastError flag is set in DllImport, call the PInvokeMarshal.
            // SaveLastWin32Error so that last error can be used later by calling
            // PInvokeMarshal.GetLastWin32Error
            if (_flags.SetLastError)
            {
                callsiteSetupCodeStream.Emit(ILOpcode.call, emitter.NewToken(
                                                 InteropTypes.GetPInvokeMarshal(context)
                                                 .GetKnownMethod("SaveLastWin32Error", null)));
            }
        }
Ejemplo n.º 4
0
        private MethodIL EmitIL()
        {
            PInvokeILCodeStreams pInvokeILCodeStreams = new PInvokeILCodeStreams();
            ILEmitter            emitter                 = pInvokeILCodeStreams.Emitter;
            ILCodeStream         fnptrLoadStream         = pInvokeILCodeStreams.FunctionPointerLoadStream;
            ILCodeStream         callsiteSetupCodeStream = pInvokeILCodeStreams.CallsiteSetupCodeStream;
            ILCodeStream         unmarshallingCodestream = pInvokeILCodeStreams.UnmarshallingCodestream;
            TypeSystemContext    context                 = _targetMethod.Context;

            // Marshal the arguments
            for (int i = 0; i < _marshallers.Length; i++)
            {
                _marshallers[i].EmitMarshallingIL(pInvokeILCodeStreams);
            }


            // if the SetLastError flag is set in DllImport, clear the error code before doing P/Invoke
            if (_importMetadata.Flags.SetLastError)
            {
                callsiteSetupCodeStream.Emit(ILOpcode.call, emitter.NewToken(
                                                 InteropTypes.GetPInvokeMarshal(context).GetKnownMethod("ClearLastWin32Error", null)));
            }

            // make the call

            DelegateMarshallingMethodThunk delegateMethod = _targetMethod as DelegateMarshallingMethodThunk;

            if (delegateMethod != null)
            {
                EmitDelegateCall(delegateMethod, pInvokeILCodeStreams);
            }
            else
            {
                TypeDesc   nativeReturnType     = _marshallers[0].NativeParameterType;
                TypeDesc[] nativeParameterTypes = new TypeDesc[_marshallers.Length - 1];

                for (int i = 1; i < _marshallers.Length; i++)
                {
                    nativeParameterTypes[i - 1] = _marshallers[i].NativeParameterType;
                }

                if (MarshalHelpers.UseLazyResolution(_targetMethod,
                                                     _importMetadata.Module,
                                                     _pInvokeILEmitterConfiguration))
                {
                    MetadataType lazyHelperType   = _targetMethod.Context.GetHelperType("InteropHelpers");
                    FieldDesc    lazyDispatchCell = new PInvokeLazyFixupField(_targetMethod);

                    fnptrLoadStream.Emit(ILOpcode.ldsflda, emitter.NewToken(lazyDispatchCell));
                    fnptrLoadStream.Emit(ILOpcode.call, emitter.NewToken(lazyHelperType
                                                                         .GetKnownMethod("ResolvePInvoke", null)));

                    MethodSignatureFlags unmanagedCallConv = _importMetadata.Flags.UnmanagedCallingConvention;

                    MethodSignature nativeSig = new MethodSignature(
                        _targetMethod.Signature.Flags | unmanagedCallConv, 0, nativeReturnType,
                        nativeParameterTypes);

                    ILLocalVariable vNativeFunctionPointer = emitter.NewLocal(_targetMethod.Context
                                                                              .GetWellKnownType(WellKnownType.IntPtr));

                    fnptrLoadStream.EmitStLoc(vNativeFunctionPointer);
                    callsiteSetupCodeStream.EmitLdLoc(vNativeFunctionPointer);
                    callsiteSetupCodeStream.Emit(ILOpcode.calli, emitter.NewToken(nativeSig));
                }
                else
                {
                    // Eager call
                    MethodSignature nativeSig = new MethodSignature(
                        _targetMethod.Signature.Flags, 0, nativeReturnType, nativeParameterTypes);

                    MethodDesc nativeMethod =
                        new PInvokeTargetNativeMethod(_targetMethod, nativeSig);

                    callsiteSetupCodeStream.Emit(ILOpcode.call, emitter.NewToken(nativeMethod));
                }
            }

            // if the SetLastError flag is set in DllImport, call the PInvokeMarshal.
            // SaveLastWin32Error so that last error can be used later by calling
            // PInvokeMarshal.GetLastWin32Error
            if (_importMetadata.Flags.SetLastError)
            {
                callsiteSetupCodeStream.Emit(ILOpcode.call, emitter.NewToken(
                                                 InteropTypes.GetPInvokeMarshal(context)
                                                 .GetKnownMethod("SaveLastWin32Error", null)));
            }

            unmarshallingCodestream.Emit(ILOpcode.ret);

            return(new  PInvokeILStubMethodIL((ILStubMethodIL)emitter.Link(_targetMethod),
                                              IsStubRequired()));
        }
Ejemplo n.º 5
0
        private MethodIL EmitIL()
        {
            PInvokeILCodeStreams pInvokeILCodeStreams = new PInvokeILCodeStreams();
            ILEmitter            emitter                 = pInvokeILCodeStreams.Emitter;
            ILCodeStream         fnptrLoadStream         = pInvokeILCodeStreams.FunctionPointerLoadStream;
            ILCodeStream         callsiteSetupCodeStream = pInvokeILCodeStreams.CallsiteSetupCodeStream;
            ILCodeStream         unmarshallingCodestream = pInvokeILCodeStreams.UnmarshallingCodestream;

            // Marshal the arguments
            for (int i = 0; i < _marshallers.Length; i++)
            {
                _marshallers[i].EmitMarshallingIL(pInvokeILCodeStreams);
            }

            // make the call
            TypeDesc nativeReturnType = _marshallers[0].NativeParameterType;

            TypeDesc[] nativeParameterTypes = new TypeDesc[_marshallers.Length - 1];

            for (int i = 1; i < _marshallers.Length; i++)
            {
                nativeParameterTypes[i - 1] = _marshallers[i].NativeParameterType;
            }

            MethodDesc      targetMethod   = _methodData.TargetMethod;
            PInvokeMetadata importMetadata = _methodData.ImportMetadata;
            PInvokeILEmitterConfiguration pinvokeILEmitterConfiguration = _methodData.PInvokeILEmitterConfiguration;
            MethodSignature nativeSig;

            // if the SetLastError flag is set in DllImport, clear the error code before doing P/Invoke
            if ((importMetadata.Attributes & PInvokeAttributes.SetLastError) == PInvokeAttributes.SetLastError)
            {
                callsiteSetupCodeStream.Emit(ILOpcode.call, emitter.NewToken(
                                                 _methodData.PInvokeMarshal.GetKnownMethod("ClearLastWin32Error", null)));
            }

            if (targetMethod is DelegateMarshallingMethodThunk)
            {
                nativeSig = new MethodSignature(MethodSignatureFlags.Static, 0, nativeReturnType, nativeParameterTypes);
                TypeDesc[] parameters = new TypeDesc[_marshallers.Length - 1];
                for (int i = 1; i < _marshallers.Length; i++)
                {
                    parameters[i - 1] = _marshallers[i].ManagedParameterType;
                }
                MethodSignature managedSignature = new MethodSignature(MethodSignatureFlags.Static, 0, _marshallers[0].ManagedParameterType, parameters);
                fnptrLoadStream.Emit(ILOpcode.call, emitter.NewToken(targetMethod.Context.GetHelperType("InteropHelpers").GetKnownMethod("GetDelegateFunctionPointer", null)));
                ILLocalVariable vDelegateStub = emitter.NewLocal(targetMethod.Context.GetWellKnownType(WellKnownType.IntPtr));
                fnptrLoadStream.EmitStLoc(vDelegateStub);
                callsiteSetupCodeStream.EmitLdLoc(vDelegateStub);
                callsiteSetupCodeStream.Emit(ILOpcode.calli, emitter.NewToken(managedSignature));
            }
            else if (MarshalHelpers.UseLazyResolution(targetMethod, importMetadata.Module, pinvokeILEmitterConfiguration))
            {
                MetadataType lazyHelperType   = targetMethod.Context.GetHelperType("InteropHelpers");
                FieldDesc    lazyDispatchCell = new PInvokeLazyFixupField((DefType)targetMethod.OwningType, importMetadata);
                fnptrLoadStream.Emit(ILOpcode.ldsflda, emitter.NewToken(lazyDispatchCell));
                fnptrLoadStream.Emit(ILOpcode.call, emitter.NewToken(lazyHelperType.GetKnownMethod("ResolvePInvoke", null)));

                MethodSignatureFlags unmanagedCallConv = PInvokeMetadata.GetUnmanagedCallingConvention(importMetadata.Attributes);

                nativeSig = new MethodSignature(
                    targetMethod.Signature.Flags | unmanagedCallConv, 0, nativeReturnType, nativeParameterTypes);

                ILLocalVariable vNativeFunctionPointer = emitter.NewLocal(targetMethod.Context.GetWellKnownType(WellKnownType.IntPtr));
                fnptrLoadStream.EmitStLoc(vNativeFunctionPointer);
                callsiteSetupCodeStream.EmitLdLoc(vNativeFunctionPointer);
                callsiteSetupCodeStream.Emit(ILOpcode.calli, emitter.NewToken(nativeSig));
            }
            else
            {
                // Eager call
                PInvokeMetadata nativeImportMetadata =
                    new PInvokeMetadata(importMetadata.Module, importMetadata.Name ?? targetMethod.Name, importMetadata.Attributes);

                nativeSig = new MethodSignature(
                    targetMethod.Signature.Flags, 0, nativeReturnType, nativeParameterTypes);

                MethodDesc nativeMethod =
                    new PInvokeTargetNativeMethod(targetMethod.OwningType, nativeSig, nativeImportMetadata, pinvokeILEmitterConfiguration.GetNextNativeMethodId());

                callsiteSetupCodeStream.Emit(ILOpcode.call, emitter.NewToken(nativeMethod));
            }

            // if the SetLastError flag is set in DllImport, call the PInvokeMarshal.SaveLastWin32Error so that last error can be used later
            // by calling PInvokeMarshal.GetLastWin32Error
            if ((importMetadata.Attributes & PInvokeAttributes.SetLastError) == PInvokeAttributes.SetLastError)
            {
                callsiteSetupCodeStream.Emit(ILOpcode.call, emitter.NewToken(
                                                 _methodData.PInvokeMarshal.GetKnownMethod("SaveLastWin32Error", null)));
            }

            unmarshallingCodestream.Emit(ILOpcode.ret);

            return(new  PInvokeILStubMethodIL((ILStubMethodIL)emitter.Link(targetMethod), IsStubRequired(), nativeSig));
        }
Ejemplo n.º 6
0
        private MethodIL EmitIL()
        {
            PInvokeILCodeStreams pInvokeILCodeStreams = new PInvokeILCodeStreams();
            ILEmitter            emitter                 = pInvokeILCodeStreams.Emitter;
            ILCodeStream         fnptrLoadStream         = pInvokeILCodeStreams.FunctionPointerLoadStream;
            ILCodeStream         callsiteSetupCodeStream = pInvokeILCodeStreams.CallsiteSetupCodeStream;
            ILCodeStream         unmarshallingCodestream = pInvokeILCodeStreams.UnmarshallingCodestream;
            TypeSystemContext    context                 = _targetMethod.Context;

            // Marshal the arguments
            for (int i = 0; i < _marshallers.Length; i++)
            {
                _marshallers[i].EmitMarshallingIL(pInvokeILCodeStreams);
            }

            // make the call
            TypeDesc nativeReturnType = _marshallers[0].NativeParameterType;

            TypeDesc[] nativeParameterTypes = new TypeDesc[_marshallers.Length - 1];

            for (int i = 1; i < _marshallers.Length; i++)
            {
                nativeParameterTypes[i - 1] = _marshallers[i].NativeParameterType;
            }

            MethodSignature nativeSig;

            // if the SetLastError flag is set in DllImport, clear the error code before doing P/Invoke
            if (_importMetadata.Flags.SetLastError)
            {
                callsiteSetupCodeStream.Emit(ILOpcode.call, emitter.NewToken(
                                                 InteropTypes.GetPInvokeMarshal(context).GetKnownMethod("ClearLastWin32Error", null)));
            }

            DelegateMarshallingMethodThunk delegateMethod = _targetMethod as DelegateMarshallingMethodThunk;

            if (delegateMethod != null)
            {
                if (delegateMethod.IsOpenStaticDelegate)
                {
                    //
                    // For Open static delegates call
                    //     InteropHelpers.GetCurrentCalleeOpenStaticDelegateFunctionPointer()
                    // which returns a function pointer. Just call the function pointer and we are done.
                    //
                    TypeDesc[] parameters = new TypeDesc[_marshallers.Length - 1];
                    for (int i = 1; i < _marshallers.Length; i++)
                    {
                        parameters[i - 1] = _marshallers[i].ManagedParameterType;
                    }

                    MethodSignature managedSignature = new MethodSignature(MethodSignatureFlags.Static, 0, _marshallers[0].ManagedParameterType, parameters);
                    fnptrLoadStream.Emit(ILOpcode.call, emitter.NewToken(delegateMethod.Context.GetHelperType("InteropHelpers").GetKnownMethod("GetCurrentCalleeOpenStaticDelegateFunctionPointer", null)));
                    ILLocalVariable vDelegateStub = emitter.NewLocal(delegateMethod.Context.GetWellKnownType(WellKnownType.IntPtr));
                    fnptrLoadStream.EmitStLoc(vDelegateStub);
                    callsiteSetupCodeStream.EmitLdLoc(vDelegateStub);
                    callsiteSetupCodeStream.Emit(ILOpcode.calli, emitter.NewToken(managedSignature));
                }
                else
                {
                    //
                    // For closed delegates call
                    //     InteropHelpers.GetCurrentCalleeDelegate<Delegate>
                    // which returns the delegate. Do a CallVirt on the invoke method.
                    //
                    MethodDesc instantiatedHelper = delegateMethod.Context.GetInstantiatedMethod(
                        delegateMethod.Context.GetHelperType("InteropHelpers").GetKnownMethod("GetCurrentCalleeDelegate", null),
                        new Instantiation((delegateMethod.DelegateType)));
                    fnptrLoadStream.Emit(ILOpcode.call, emitter.NewToken(instantiatedHelper));

                    ILLocalVariable vDelegateStub = emitter.NewLocal(delegateMethod.DelegateType);
                    fnptrLoadStream.EmitStLoc(vDelegateStub);
                    fnptrLoadStream.EmitLdLoc(vDelegateStub);
                    MethodDesc invokeMethod = delegateMethod.DelegateType.GetKnownMethod("Invoke", null);
                    callsiteSetupCodeStream.Emit(ILOpcode.callvirt, emitter.NewToken(invokeMethod));
                }
            }
            else if (MarshalHelpers.UseLazyResolution(_targetMethod, _importMetadata.Module, _pInvokeILEmitterConfiguration))
            {
                MetadataType lazyHelperType   = _targetMethod.Context.GetHelperType("InteropHelpers");
                FieldDesc    lazyDispatchCell = new PInvokeLazyFixupField((DefType)_targetMethod.OwningType, _importMetadata);
                fnptrLoadStream.Emit(ILOpcode.ldsflda, emitter.NewToken(lazyDispatchCell));
                fnptrLoadStream.Emit(ILOpcode.call, emitter.NewToken(lazyHelperType.GetKnownMethod("ResolvePInvoke", null)));

                MethodSignatureFlags unmanagedCallConv = _importMetadata.Flags.UnmanagedCallingConvention;

                nativeSig = new MethodSignature(
                    _targetMethod.Signature.Flags | unmanagedCallConv, 0, nativeReturnType, nativeParameterTypes);

                ILLocalVariable vNativeFunctionPointer = emitter.NewLocal(_targetMethod.Context.GetWellKnownType(WellKnownType.IntPtr));
                fnptrLoadStream.EmitStLoc(vNativeFunctionPointer);
                callsiteSetupCodeStream.EmitLdLoc(vNativeFunctionPointer);
                callsiteSetupCodeStream.Emit(ILOpcode.calli, emitter.NewToken(nativeSig));
            }
            else
            {
                // Eager call
                PInvokeMetadata nativeImportMetadata =
                    new PInvokeMetadata(_importMetadata.Module, _importMetadata.Name ?? _targetMethod.Name, _importMetadata.Flags);

                nativeSig = new MethodSignature(
                    _targetMethod.Signature.Flags, 0, nativeReturnType, nativeParameterTypes);

                MethodDesc nativeMethod =
                    new PInvokeTargetNativeMethod(_targetMethod.OwningType, nativeSig, nativeImportMetadata, _pInvokeILEmitterConfiguration.GetNextNativeMethodId());

                callsiteSetupCodeStream.Emit(ILOpcode.call, emitter.NewToken(nativeMethod));
            }

            // if the SetLastError flag is set in DllImport, call the PInvokeMarshal.SaveLastWin32Error so that last error can be used later
            // by calling PInvokeMarshal.GetLastWin32Error
            if (_importMetadata.Flags.SetLastError)
            {
                callsiteSetupCodeStream.Emit(ILOpcode.call, emitter.NewToken(
                                                 InteropTypes.GetPInvokeMarshal(context).GetKnownMethod("SaveLastWin32Error", null)));
            }

            unmarshallingCodestream.Emit(ILOpcode.ret);

            return(new  PInvokeILStubMethodIL((ILStubMethodIL)emitter.Link(_targetMethod), IsStubRequired()));
        }
Ejemplo n.º 7
0
        private MethodIL EmitIL()
        {
            // We have 4 code streams:
            // - _marshallingCodeStream is used to convert each argument into a native type and
            // store that into the local
            // - callsiteSetupCodeStream is used to used to load each previously generated local
            // and call the actual target native method.
            // - _returnValueMarshallingCodeStream is used to convert the native return value
            // to managed one.
            // - _unmarshallingCodestream is used to propagate [out] native arguments values to
            // managed ones.

            ILEmitter    emitter                          = new ILEmitter();
            ILCodeStream fnptrLoadStream                  = emitter.NewCodeStream();
            ILCodeStream marshallingCodeStream            = emitter.NewCodeStream();
            ILCodeStream callsiteSetupCodeStream          = emitter.NewCodeStream();
            ILCodeStream returnValueMarshallingCodeStream = emitter.NewCodeStream();
            ILCodeStream unmarshallingCodestream          = emitter.NewCodeStream();

            // Marshal the arguments
            for (int i = 0; i < _marshallers.Length; i++)
            {
                Marshaller marshaller = _marshallers[i];
                marshaller.EmitMarshallingIL(emitter, marshallingCodeStream, callsiteSetupCodeStream, unmarshallingCodestream, returnValueMarshallingCodeStream);
            }

            // make the call
            TypeDesc nativeReturnType = _marshallers[0].NativeType;

            TypeDesc[] nativeParameterTypes = new TypeDesc[_marshallers.Length - 1];

            for (int i = 1; i < _marshallers.Length; i++)
            {
                nativeParameterTypes[i - 1] = _marshallers[i].NativeType;
            }

            MethodDesc      targetMethod   = _methodData.TargetMethod;
            PInvokeMetadata importMetadata = _methodData.ImportMetadata;
            PInvokeILEmitterConfiguration pinvokeILEmitterConfiguration = _methodData.PInvokeILEmitterConfiguration;

            // if the SetLastError flag is set in DllImport, clear the error code before doing P/Invoke
            if ((importMetadata.Attributes & PInvokeAttributes.SetLastError) == PInvokeAttributes.SetLastError)
            {
                callsiteSetupCodeStream.Emit(ILOpcode.call, emitter.NewToken(
                                                 _methodData.PInvokeMarshal.GetKnownMethod("ClearLastWin32Error", null)));
            }

            if (MarshalHelpers.UseLazyResolution(targetMethod, importMetadata.Module, pinvokeILEmitterConfiguration))
            {
                MetadataType lazyHelperType   = targetMethod.Context.GetHelperType("InteropHelpers");
                FieldDesc    lazyDispatchCell = new PInvokeLazyFixupField((DefType)targetMethod.OwningType, importMetadata);
                fnptrLoadStream.Emit(ILOpcode.ldsflda, emitter.NewToken(lazyDispatchCell));
                fnptrLoadStream.Emit(ILOpcode.call, emitter.NewToken(lazyHelperType.GetKnownMethod("ResolvePInvoke", null)));

                MethodSignatureFlags unmanagedCallConv = PInvokeMetadata.GetUnmanagedCallingConvention(importMetadata.Attributes);

                MethodSignature nativeCalliSig = new MethodSignature(
                    targetMethod.Signature.Flags | unmanagedCallConv, 0, nativeReturnType, nativeParameterTypes);

                ILLocalVariable vNativeFunctionPointer = emitter.NewLocal(targetMethod.Context.GetWellKnownType(WellKnownType.IntPtr));
                fnptrLoadStream.EmitStLoc(vNativeFunctionPointer);
                callsiteSetupCodeStream.EmitLdLoc(vNativeFunctionPointer);
                callsiteSetupCodeStream.Emit(ILOpcode.calli, emitter.NewToken(nativeCalliSig));
            }
            else
            {
                // Eager call
                PInvokeMetadata nativeImportMetadata =
                    new PInvokeMetadata(importMetadata.Module, importMetadata.Name ?? targetMethod.Name, importMetadata.Attributes);

                MethodSignature nativeSig = new MethodSignature(
                    targetMethod.Signature.Flags, 0, nativeReturnType, nativeParameterTypes);

                MethodDesc nativeMethod =
                    new PInvokeTargetNativeMethod(targetMethod.OwningType, nativeSig, nativeImportMetadata, pinvokeILEmitterConfiguration.GetNextNativeMethodId());

                callsiteSetupCodeStream.Emit(ILOpcode.call, emitter.NewToken(nativeMethod));
            }

            // if the SetLastError flag is set in DllImport, call the PInvokeMarshal.SaveLastWin32Error so that last error can be used later
            // by calling PInvokeMarshal.GetLastWin32Error
            if ((importMetadata.Attributes & PInvokeAttributes.SetLastError) == PInvokeAttributes.SetLastError)
            {
                callsiteSetupCodeStream.Emit(ILOpcode.call, emitter.NewToken(
                                                 _methodData.PInvokeMarshal.GetKnownMethod("SaveLastWin32Error", null)));
            }

            unmarshallingCodestream.Emit(ILOpcode.ret);

            return(emitter.Link(targetMethod));
        }