/// <summary>
/// Attempt a virtual dispatch on a given instanceType based on the method found via a metadata token
/// </summary>
private static bool TryDispatchMethodOnTarget_Inner(NativeFormatModuleInfo module, int metadataToken, RuntimeTypeHandle targetInstanceType, out IntPtr methodAddress)
{
#if SUPPORTS_NATIVE_METADATA_TYPE_LOADING
TypeSystemContext context = TypeSystemContextFactory.Create();
NativeFormatMetadataUnit metadataUnit = context.ResolveMetadataUnit(module);
MethodDesc targetMethod = metadataUnit.GetMethod(metadataToken.AsHandle(), null);
TypeDesc instanceType = context.ResolveRuntimeTypeHandle(targetInstanceType);
MethodDesc realTargetMethod = targetMethod;
// For non-interface methods we support the target method not being the exact target. (This allows
// a canonical method to be passed in and work for any generic type instantiation.)
if (!targetMethod.OwningType.IsInterface)
{
realTargetMethod = instanceType.FindMethodOnTypeWithMatchingTypicalMethod(targetMethod);
}
bool success = LazyVTableResolver.TryDispatchMethodOnTarget(instanceType, realTargetMethod, out methodAddress);
TypeSystemContextFactory.Recycle(context);
return(success);
#else
methodAddress = IntPtr.Zero;
return(false);
#endif
}
/// <summary>
/// Attempt to convert the dispatch cell to a metadata token to a more efficient vtable dispatch or interface/slot dispatch.
/// Failure to convert is not a correctness issue. We also support performing a dispatch based on metadata token alone.
/// </summary>
private static DispatchCellInfo ConvertDispatchCellInfo_Inner(NativeFormatModuleInfo module, DispatchCellInfo cellInfo)
{
Debug.Assert(cellInfo.CellType == DispatchCellType.MetadataToken);
TypeSystemContext context = TypeSystemContextFactory.Create();
MethodDesc targetMethod = context.ResolveMetadataUnit(module).GetMethod(cellInfo.MetadataToken.AsHandle(), null);
Debug.Assert(!targetMethod.HasInstantiation); // At this time we do not support generic virtuals through the dispatch mechanism
Debug.Assert(targetMethod.IsVirtual);
if (targetMethod.OwningType.IsInterface)
{
if (!LazyVTableResolver.TryGetInterfaceSlotNumberFromMethod(targetMethod, out cellInfo.InterfaceSlot))
{
// Unable to resolve interface method. Fail, by not mutating cellInfo
return cellInfo;
}
if (!targetMethod.OwningType.RetrieveRuntimeTypeHandleIfPossible())
{
new TypeBuilder().BuildType(targetMethod.OwningType);
}
cellInfo.CellType = DispatchCellType.InterfaceAndSlot;
cellInfo.InterfaceType = targetMethod.OwningType.RuntimeTypeHandle.ToIntPtr();
cellInfo.MetadataToken = 0;
}
else
{
// Virtual function case, attempt to resolve to a VTable slot offset.
// If the offset is less than 4096 update the cellInfo
#if DEBUG
// The path of resolving a metadata token at dispatch time is relatively rare in practice.
// Force it to occur in debug builds with much more regularity
if ((s_ConvertDispatchCellInfoCounter % 16) == 0)
{
s_ConvertDispatchCellInfoCounter++;
TypeSystemContextFactory.Recycle(context);
return cellInfo;
}
s_ConvertDispatchCellInfoCounter++;
#endif
int slotIndexOfMethod = LazyVTableResolver.VirtualMethodToSlotIndex(targetMethod);
int vtableOffset = -1;
if (slotIndexOfMethod >= 0)
vtableOffset = LazyVTableResolver.SlotIndexToEETypeVTableOffset(slotIndexOfMethod);
if ((vtableOffset < 4096) && (vtableOffset != -1))
{
cellInfo.CellType = DispatchCellType.VTableOffset;
cellInfo.VTableOffset = checked((uint)vtableOffset);
cellInfo.MetadataToken = 0;
}
// Otherwise, do nothing, and resolve with a metadata dispatch later
}
TypeSystemContextFactory.Recycle(context);
return cellInfo;
}