private unsafe void HandleInvokeFunctionFromNative(IntPtr obj, FFrame stack, IntPtr result,
UFunction.FuncInvokerManaged managedFunctionInvoker)
{
IntPtr function = stack.CurrentNativeFunction;
IntPtr paramsBuffer = stack.Locals;
if (managedFunctionInvoker != null)
{
// Call the managed function invoker which will marshal the params from the native params buffer and then call the
// target managed function
managedFunctionInvoker(paramsBuffer, obj);
}
// Copy out params back from the locals buffer
if (Native_UFunction.HasAnyFunctionFlags(function, EFunctionFlags.HasOutParms))
{
// This assumes that UProperty will be itterated in the exact same order as the caller created stack->OutParms
// (we could iterate stack->OutParms until nullptr but it isn't null terminated on release builds)
FOutParmRec *outParms = stack.OutParmsPtr;
foreach (IntPtr paramProp in new NativeReflection.NativeFieldIterator(Runtime.Classes.UProperty, function, false))
{
EPropertyFlags paramFlags = Native_UProperty.GetPropertyFlags(paramProp);
if ((paramFlags & EPropertyFlags.OutParm) == EPropertyFlags.OutParm &&
(paramFlags & EPropertyFlags.ConstParm) != EPropertyFlags.ConstParm)
{
Debug.Assert(outParms->Property == paramProp);
// - REMOVING the DestroyValue call. The issue with this DestroyValue call is that PropAddr
// and paramsBuffer can (will?) be refering to the same data which we should have set in
// managedFunctionInvoker. So a call to DestroyValue would be destroying the data we want!
// Though if PropAddr is for some reason still holding onto unknown memory this will leak
// memory and we will need to investigate further.
// - The "refering to the same data" is because of the params Memcpy in UObject::ProcessEvent.
// They wont have the same address but their inital data will be the same and as such
// things like FString data pointer would be pointing to the same address.
// - We may still need to call DestroyValue in the BP/VM code path above.
// Destroy the existing memory (this assumed the existing memory is valid or at least memzerod)
//Native_UProperty.DestroyValue(paramProp, outParms->PropAddr);
// A raw memcpy should be OK since the managed invoker should have set this memory appropriately.
FMemory.Memcpy(outParms->PropAddr,
paramsBuffer + Native_UProperty.GetOffset_ForUFunction(paramProp),
Native_UProperty.Get_ElementSize(paramProp));// Should be ArrayDim*ElementSize but ArrayDim should always be 1 for params
outParms = outParms->NextOutParamPtr;
}
}
}
// We assume that the caller will clean up the memory held by stack->Locals so we don't iterate over the
// DestructorLink as we do in HandleInvokeFunctionFromBP. HandleInvokeFunctionFromBP needs to as it creates
// copies of data when calling stack->Step() which don't occur here as we use the existing stack->Locals buffer.
}
private unsafe void HandleInvokeFunctionFromBP(IntPtr obj, FFrame *stack, IntPtr result,
UFunction.FuncInvokerManaged managedFunctionInvoker)
{
// NOTE: ScriptCore.cpp uses PropertiesSize instead of ParamsSize. Is it ever any different? (it says alignment
// may make them different) If it is different we should probably use PropertiesSize (including in generated code /
// IL) as ScriptCore.cpp uses a memcpy of our memory.
Debug.Assert(Native_UStruct.Get_PropertiesSize(stack->CurrentNativeFunction) ==
Native_UFunction.Get_ParmsSize(stack->CurrentNativeFunction));
IntPtr function = stack->CurrentNativeFunction;
int paramsSize = Native_UFunction.Get_ParmsSize(function);
int numParams = Native_UFunction.Get_NumParms(function);
bool hasOutParams = Native_UFunction.HasAnyFunctionFlags(function, EFunctionFlags.HasOutParms);
IntPtr *outParamsBufferPtr = stackalloc IntPtr[numParams];
byte * paramsBufferPtr = stackalloc byte[paramsSize];
IntPtr paramsBuffer = (IntPtr)paramsBufferPtr;
// We could skip this memzero as stackalloc will (always?) zero memory even though the spec states
// "The content of the newly allocated memory is undefined."
// https://github.com/dotnet/coreclr/issues/1279
FMemory.Memzero(paramsBuffer, paramsSize);
if (hasOutParams)
{
int paramIndex = 0;
foreach (IntPtr param in new NativeReflection.NativeFieldIterator(Runtime.Classes.UProperty, function, false))
{
// Not required but using for Debug.Assert() when getting the value
stack->MostRecentPropertyAddress = IntPtr.Zero;
stack->Step(stack->Object, paramsBuffer + Native_UProperty.GetOffset_ForUFunction(param));
outParamsBufferPtr[paramIndex] = stack->MostRecentPropertyAddress;
if (Native_UProperty.HasAnyPropertyFlags(param, EPropertyFlags.ReturnParm))
{
// This should be UObject::execEndFunctionParms which will just do "stack->Code--;" for allowing
// the caller to use PFINISH aftwards
outParamsBufferPtr[paramIndex] = result;
}
paramIndex++;
}
}
else
{
foreach (IntPtr param in new NativeReflection.NativeFieldIterator(Runtime.Classes.UProperty, function, false))
{
stack->Step(stack->Object, paramsBuffer + Native_UProperty.GetOffset_ForUFunction(param));
}
}
stack->PFinish();// Skip EX_EndFunctionParms
// Call the managed function invoker which will marshal the params from the native params buffer and then call the
// target managed function
managedFunctionInvoker(paramsBuffer, obj);
// Copy out params from the temp buffer
//if (hasOutParams) // 4.20 DestructorLink change (see below)
{
int paramIndex = 0;
foreach (IntPtr paramProp in new NativeReflection.NativeFieldIterator(Runtime.Classes.UProperty, function, false))
{
EPropertyFlags paramFlags = Native_UProperty.GetPropertyFlags(paramProp);
if ((paramFlags & EPropertyFlags.OutParm) == EPropertyFlags.OutParm &&
(paramFlags & EPropertyFlags.ConstParm) != EPropertyFlags.ConstParm)
{
Debug.Assert(outParamsBufferPtr[paramIndex] != IntPtr.Zero);
// - See "REMOVING the DestroyValue call" below.
// Destroy the existing memory (this assumed the existing memory is valid or at least memzerod)
//Native_UProperty.DestroyValue(paramProp, outParamsBufferPtr[paramIndex]);
// A raw memcpy should be OK since the managed invoker should have set this memory appropriately.
FMemory.Memcpy(outParamsBufferPtr[paramIndex],
paramsBuffer + Native_UProperty.GetOffset_ForUFunction(paramProp),
Native_UProperty.Get_ElementSize(paramProp));// Should be ArrayDim*ElementSize but ArrayDim should always be 1 for params
}
else
{
// 4.20 the original DestructorLink code doesn't work as expected (did it ever work?). DestructorLink seems to only be
// used on delegate functions (e.g. /Script/Engine.ActorOnClickedSignature__DelegateSignature).
// - For now call destroy everything other than out params (is this safe?)
// - TODO: Replace this with custom Stack.Code stepping as described above?
Native_UProperty.DestroyValue_InContainer(paramProp, paramsBuffer);
}
paramIndex++;
}
}
// Parameters are copied when calling stack->Step(). We are responsible for destroying non-blittable types
// which were copied (FString, TArray, etc). For C++ this works out well due to the copy constructors etc.
//
// Example where an FString is constructed from stack->Step():
// UObject::execStringConst(...) { *(FString*)RESULT_PARAM = (ANSICHAR*)Stack.Code; }
//
// For C# it might be better if we reimplemented all of the IMPLEMENT_VM_FUNCTION functions to reduce the amount
// of copying as we currently need ANOTHER copy to get it from the temp buffer into a C# type (which is done
// inside the managedFunctionInvoker function)
/*foreach (IntPtr paramProp in new NativeReflection.NativeFieldIterator(Runtime.Classes.UProperty, function,
* EFieldIteratorType.Destructor, false))
* {
* // When is this ever false? It seems to be checked in UObject::ProcessEvent()
* // "Destroy local variables except function parameters." - used for BP locals?
* Debug.Assert(Native_UProperty.IsInContainer(paramProp, paramsSize));
*
* // Out params are copied to the memory maintained by the caller so only destroy "by value" parameters.
* if (!Native_UProperty.HasAnyPropertyFlags(paramProp, EPropertyFlags.OutParm))
* {
* Native_UProperty.DestroyValue_InContainer(paramProp, paramsBuffer);
* }
* }*/
}
/// <summary>
/// Returns this property's propertyflags
/// </summary>
/// <returns></returns>
public EPropertyFlags GetPropertyFlags()
{
return(Native_UProperty.GetPropertyFlags(Address));
}