public GenericDictionaryLookup ComputeGenericLookup(MethodDesc contextMethod, ReadyToRunHelperId lookupKind, object targetOfLookup)
{
GenericContextSource contextSource;
if (contextMethod.RequiresInstMethodDescArg())
{
contextSource = GenericContextSource.MethodParameter;
}
else if (contextMethod.RequiresInstMethodTableArg())
{
contextSource = GenericContextSource.TypeParameter;
}
else
{
Debug.Assert(contextMethod.AcquiresInstMethodTableFromThis());
contextSource = GenericContextSource.ThisObject;
}
// Can we do a fixed lookup? Start by checking if we can get to the dictionary.
// Context source having a vtable with fixed slots is a prerequisite.
if (contextSource == GenericContextSource.MethodParameter ||
HasFixedSlotVTable(contextMethod.OwningType))
{
DictionaryLayoutNode dictionaryLayout;
if (contextSource == GenericContextSource.MethodParameter)
{
dictionaryLayout = _nodeFactory.GenericDictionaryLayout(contextMethod);
}
else
{
dictionaryLayout = _nodeFactory.GenericDictionaryLayout(contextMethod.OwningType);
}
// If the dictionary layout has fixed slots, we can compute the lookup now. Otherwise defer to helper.
if (dictionaryLayout.HasFixedSlots)
{
int pointerSize = _nodeFactory.Target.PointerSize;
GenericLookupResult lookup = ReadyToRunGenericHelperNode.GetLookupSignature(_nodeFactory, lookupKind, targetOfLookup);
int dictionarySlot = dictionaryLayout.GetSlotForEntry(lookup);
int dictionaryOffset = dictionarySlot * pointerSize;
if (contextSource == GenericContextSource.MethodParameter)
{
return(GenericDictionaryLookup.CreateFixedLookup(contextSource, dictionaryOffset));
}
else
{
int vtableSlot = VirtualMethodSlotHelper.GetGenericDictionarySlot(_nodeFactory, contextMethod.OwningType);
int vtableOffset = EETypeNode.GetVTableOffset(pointerSize) + vtableSlot * pointerSize;
return(GenericDictionaryLookup.CreateFixedLookup(contextSource, vtableOffset, dictionaryOffset));
}
}
}
// Fixed lookup not possible - use helper.
return(GenericDictionaryLookup.CreateHelperLookup(contextSource));
}
public GenericDictionaryLookup ComputeGenericLookup(MethodDesc contextMethod, ReadyToRunHelperId lookupKind, object targetOfLookup)
{
if (targetOfLookup is TypeSystemEntity typeSystemEntity)
{
_nodeFactory.TypeSystemContext.DetectGenericCycles(contextMethod, typeSystemEntity);
}
GenericContextSource contextSource;
if (contextMethod.RequiresInstMethodDescArg())
{
contextSource = GenericContextSource.MethodParameter;
}
else if (contextMethod.RequiresInstMethodTableArg())
{
contextSource = GenericContextSource.TypeParameter;
}
else
{
Debug.Assert(contextMethod.AcquiresInstMethodTableFromThis());
contextSource = GenericContextSource.ThisObject;
}
//
// Some helpers represent logical concepts that might not be something that can be looked up in a dictionary
//
// Downgrade type handle for casting to a normal type handle if possible
if (lookupKind == ReadyToRunHelperId.TypeHandleForCasting)
{
var type = (TypeDesc)targetOfLookup;
if (!type.IsRuntimeDeterminedType ||
(!((RuntimeDeterminedType)type).CanonicalType.IsCanonicalDefinitionType(CanonicalFormKind.Universal) &&
!((RuntimeDeterminedType)type).CanonicalType.IsNullable))
{
if (type.IsNullable)
{
targetOfLookup = type.Instantiation[0];
}
lookupKind = ReadyToRunHelperId.NecessaryTypeHandle;
}
}
// We don't have separate entries for necessary type handles to avoid possible duplication
if (lookupKind == ReadyToRunHelperId.NecessaryTypeHandle)
{
lookupKind = ReadyToRunHelperId.TypeHandle;
}
// Can we do a fixed lookup? Start by checking if we can get to the dictionary.
// Context source having a vtable with fixed slots is a prerequisite.
if (contextSource == GenericContextSource.MethodParameter ||
HasFixedSlotVTable(contextMethod.OwningType))
{
DictionaryLayoutNode dictionaryLayout;
if (contextSource == GenericContextSource.MethodParameter)
{
dictionaryLayout = _nodeFactory.GenericDictionaryLayout(contextMethod);
}
else
{
dictionaryLayout = _nodeFactory.GenericDictionaryLayout(contextMethod.OwningType);
}
// If the dictionary layout has fixed slots, we can compute the lookup now. Otherwise defer to helper.
if (dictionaryLayout.HasFixedSlots)
{
int pointerSize = _nodeFactory.Target.PointerSize;
GenericLookupResult lookup = ReadyToRunGenericHelperNode.GetLookupSignature(_nodeFactory, lookupKind, targetOfLookup);
int dictionarySlot = dictionaryLayout.GetSlotForFixedEntry(lookup);
if (dictionarySlot != -1)
{
int dictionaryOffset = dictionarySlot * pointerSize;
bool indirectLastOffset = lookup.LookupResultReferenceType(_nodeFactory) == GenericLookupResultReferenceType.Indirect;
if (contextSource == GenericContextSource.MethodParameter)
{
return(GenericDictionaryLookup.CreateFixedLookup(contextSource, dictionaryOffset, indirectLastOffset: indirectLastOffset));
}
else
{
int vtableSlot = VirtualMethodSlotHelper.GetGenericDictionarySlot(_nodeFactory, contextMethod.OwningType);
int vtableOffset = EETypeNode.GetVTableOffset(pointerSize) + vtableSlot * pointerSize;
return(GenericDictionaryLookup.CreateFixedLookup(contextSource, vtableOffset, dictionaryOffset, indirectLastOffset: indirectLastOffset));
}
}
}
}
// Fixed lookup not possible - use helper.
return(GenericDictionaryLookup.CreateHelperLookup(contextSource, lookupKind, targetOfLookup));
}