/// <summary>
/// Get the GC layout of a type when used as a field.
/// NOTE: if the fieldtype is a reference type, this function will return GCLayout.None
/// Consumers of the api must handle that special case.
/// </summary>
private unsafe TypeBuilder.GCLayout GetFieldGCLayout(TypeDesc fieldType)
{
if (!fieldType.IsValueType)
{
if (fieldType.IsPointer)
return TypeBuilder.GCLayout.None;
else
return TypeBuilder.GCLayout.SingleReference;
}
// Is this a type that already exists? If so, get its gclayout from the EEType directly
if (fieldType.RetrieveRuntimeTypeHandleIfPossible())
{
return new TypeBuilder.GCLayout(fieldType.RuntimeTypeHandle);
}
// The type of the field must be a valuetype that is dynamically being constructed
if (fieldType.IsTemplateCanonical())
{
// Pull the GC Desc from the canonical instantiation
TypeDesc templateType = fieldType.ComputeTemplate();
bool success = templateType.RetrieveRuntimeTypeHandleIfPossible();
Debug.Assert(success);
return new TypeBuilder.GCLayout(templateType.RuntimeTypeHandle);
}
else
{
// Use the type builder state's computed InstanceGCLayout
var instanceGCLayout = fieldType.GetOrCreateTypeBuilderState().InstanceGCLayout;
if (instanceGCLayout == null)
return TypeBuilder.GCLayout.None;
return new TypeBuilder.GCLayout(instanceGCLayout, false /* Always represents a valuetype as the reference type case
is handled above with the GCLayout.SingleReference return */);
}
}
// Get the GC layout of a type. Handles pre-created, universal template, and non-universal template cases
// Only to be used for getting the instance layout of non-valuetypes.
/// <summary>
/// Get the GC layout of a type. Handles pre-created, universal template, and non-universal template cases
/// Only to be used for getting the instance layout of non-valuetypes that are used as base types
/// </summary>
/// <param name="type"></param>
/// <returns></returns>
private unsafe TypeBuilder.GCLayout GetInstanceGCLayout(TypeDesc type)
{
Debug.Assert(!type.IsCanonicalSubtype(CanonicalFormKind.Any));
Debug.Assert(!type.IsValueType);
if (type.RetrieveRuntimeTypeHandleIfPossible())
{
return new TypeBuilder.GCLayout(type.RuntimeTypeHandle);
}
if (type.IsTemplateCanonical())
{
var templateType = type.ComputeTemplate();
bool success = templateType.RetrieveRuntimeTypeHandleIfPossible();
Debug.Assert(success && !templateType.RuntimeTypeHandle.IsNull());
return new TypeBuilder.GCLayout(templateType.RuntimeTypeHandle);
}
else
{
TypeBuilderState state = type.GetOrCreateTypeBuilderState();
if (state.InstanceGCLayout == null)
return TypeBuilder.GCLayout.None;
else
return new TypeBuilder.GCLayout(state.InstanceGCLayout, true);
}
}
