public EagerlyBuiltVTableSliceNode(TypeDesc type)
: base(type)
{
var slots = new ArrayBuilder <MethodDesc>();
DefType defType = _type.GetClosestDefType();
foreach (var method in defType.GetAllVirtualMethods())
{
slots.Add(method);
}
_slots = slots.ToArray();
}
/// <summary>
/// Gets a value indicating whether '<paramref name="type"/>' might have a non-empty dispatch map.
/// Note that this is only an approximation because we might not be able to take into account
/// whether the interface methods are actually used.
/// </summary>
public static bool MightHaveInterfaceDispatchMap(TypeDesc type, NodeFactory factory)
{
if (type.IsArrayTypeWithoutGenericInterfaces())
{
return(false);
}
if (!type.IsArray && !type.IsDefType)
{
return(false);
}
// Interfaces don't have a dispatch map because we dispatch them based on the
// dispatch map of the implementing class.
// The only exception are IDynamicInterfaceCastable scenarios that dispatch
// using the interface dispatch map.
// We generate the dispatch map irrespective of whether the interface actually
// implements any methods (we don't run the for loop below) so that at runtime
// we can distinguish between "the interface returned by IDynamicInterfaceCastable
// wasn't marked as [DynamicInterfaceCastableImplementation]" and "we couldn't find an
// implementation". We don't want to use the custom attribute for that at runtime because
// that's reflection and this should work without reflection.
if (type.IsInterface)
{
return(((MetadataType)type).IsDynamicInterfaceCastableImplementation());
}
TypeDesc declType = type.GetClosestDefType();
for (int interfaceIndex = 0; interfaceIndex < declType.RuntimeInterfaces.Length; interfaceIndex++)
{
DefType interfaceType = declType.RuntimeInterfaces[interfaceIndex];
InstantiatedType interfaceOnDefinitionType = interfaceType.IsTypeDefinition ?
null :
(InstantiatedType)declType.GetTypeDefinition().RuntimeInterfaces[interfaceIndex];
IEnumerable <MethodDesc> slots;
// If the vtable has fixed slots, we can query it directly.
// If it's a lazily built vtable, we might not be able to query slots
// just yet, so approximate by looking at all methods.
VTableSliceNode vtableSlice = factory.VTable(interfaceType);
if (vtableSlice.HasFixedSlots)
{
slots = vtableSlice.Slots;
}
else
{
slots = interfaceType.GetAllVirtualMethods();
}
foreach (MethodDesc slotMethod in slots)
{
MethodDesc declMethod = slotMethod;
Debug.Assert(!declMethod.Signature.IsStatic && declMethod.IsVirtual);
if (interfaceOnDefinitionType != null)
{
declMethod = factory.TypeSystemContext.GetMethodForInstantiatedType(declMethod.GetTypicalMethodDefinition(), interfaceOnDefinitionType);
}
var implMethod = declType.GetTypeDefinition().ResolveInterfaceMethodToVirtualMethodOnType(declMethod);
if (implMethod != null)
{
return(true);
}
else
{
DefaultInterfaceMethodResolution result = declType.ResolveInterfaceMethodToDefaultImplementationOnType(slotMethod, out _);
if (result != DefaultInterfaceMethodResolution.None)
{
return(true);
}
}
}
}
return(false);
}