/// <summary>
/// Resolve a virtual function call (to a virtual method, not an interface method)
/// </summary>
/// <param name="targetMethod"></param>
/// <param name="objectType"></param>
/// <returns>The override of the virtual method that should be called</returns>
private static MethodDesc FindVirtualFunctionTargetMethodOnObjectType(MethodDesc targetMethod, MetadataType objectType)
{
// Step 1, convert objectType to uninstantiated form
MetadataType uninstantiatedType = objectType;
MethodDesc initialTargetMethod = targetMethod;
InstantiatedType initialInstantiatedType = objectType as InstantiatedType;
if (initialInstantiatedType != null)
{
uninstantiatedType = (MetadataType)initialInstantiatedType.GetTypeDefinition();
}
// Step 2, convert targetMethod to method in type hierarchy of uninstantiated form
targetMethod = targetMethod.GetMethodDefinition();
if (uninstantiatedType != objectType)
{
targetMethod = uninstantiatedType.FindMethodOnTypeWithMatchingTypicalMethod(targetMethod);
}
// Step 3, find unification group of target method
UnificationGroup group = new UnificationGroup(FindSlotDefiningMethodForVirtualMethod(targetMethod));
FindBaseUnificationGroup(uninstantiatedType, group);
// Step 4, name/sig match virtual function resolve
MethodDesc resolutionTarget = FindNameSigOverrideForVirtualMethod(group.DefiningMethod, uninstantiatedType);
if (resolutionTarget == null)
{
return(null);
}
// Step 5, convert resolution target from uninstantiated form target to objecttype target,
// and instantiate as appropriate
if (uninstantiatedType != objectType)
{
resolutionTarget = objectType.FindMethodOnTypeWithMatchingTypicalMethod(resolutionTarget);
}
if (initialTargetMethod.HasInstantiation)
{
resolutionTarget = resolutionTarget.MakeInstantiatedMethod(initialTargetMethod.Instantiation);
}
return(resolutionTarget);
}
private static void FindBaseUnificationGroup(MetadataType currentType, UnificationGroup unificationGroup)
{
MethodDesc originalDefiningMethod = unificationGroup.DefiningMethod;
MethodDesc methodImpl = FindImplFromDeclFromMethodImpls(currentType, unificationGroup.DefiningMethod);
if (methodImpl != null)
{
if (methodImpl.RequiresSlotUnification())
{
unificationGroup.AddMethodRequiringSlotUnification(unificationGroup.DefiningMethod);
unificationGroup.AddMethodRequiringSlotUnification(methodImpl);
}
unificationGroup.SetDefiningMethod(methodImpl);
}
MethodDesc nameSigMatchMethod = FindMatchingVirtualMethodOnTypeByNameAndSigWithSlotCheck(unificationGroup.DefiningMethod, currentType, reverseMethodSearch: true);
MetadataType baseType = currentType.MetadataBaseType;
// Unless the current type has a name/sig match for the group, look to the base type to define the unification group further
if ((nameSigMatchMethod == null) && (baseType != null))
{
FindBaseUnificationGroup(baseType, unificationGroup);
}
Debug.Assert(unificationGroup.IsInGroupOrIsDefiningSlot(originalDefiningMethod));
// Now, we have the unification group from the type, or have discovered its defined on the current type.
// Adjust the group to contain all of the elements that are added to it on this type, remove the components that
// have seperated themselves from the group
// Start with removing methods that seperated themselves from the group via name/sig matches
MethodDescHashtable separatedMethods = null;
foreach (MethodDesc memberMethod in unificationGroup.Members)
{
MethodDesc nameSigMatchMemberMethod = FindMatchingVirtualMethodOnTypeByNameAndSigWithSlotCheck(memberMethod, currentType, reverseMethodSearch: true);
if (nameSigMatchMemberMethod != null && nameSigMatchMemberMethod != memberMethod)
{
if (separatedMethods == null)
{
separatedMethods = new MethodDescHashtable();
}
separatedMethods.AddOrGetExisting(memberMethod);
}
}
if (separatedMethods != null)
{
foreach (MethodDesc seperatedMethod in MethodDescHashtable.Enumerator.Get(separatedMethods))
{
unificationGroup.RemoveFromGroup(seperatedMethod);
}
}
// Next find members which have seperated or added themselves to the group via MethodImpls
foreach (MethodImplRecord methodImplRecord in currentType.VirtualMethodImplsForType)
{
MethodDesc declSlot = FindSlotDefiningMethodForVirtualMethod(methodImplRecord.Decl);
MethodDesc implSlot = FindSlotDefiningMethodForVirtualMethod(methodImplRecord.Body);
if (unificationGroup.IsInGroup(declSlot) && !unificationGroup.IsInGroupOrIsDefiningSlot(implSlot))
{
unificationGroup.RemoveFromGroup(declSlot);
if (separatedMethods == null)
{
separatedMethods = new MethodDescHashtable();
}
separatedMethods.AddOrGetExisting(declSlot);
if (unificationGroup.RequiresSlotUnification(declSlot) || implSlot.RequiresSlotUnification())
{
if (implSlot.Signature.EqualsWithCovariantReturnType(unificationGroup.DefiningMethod.Signature))
{
unificationGroup.AddMethodRequiringSlotUnification(declSlot);
unificationGroup.AddMethodRequiringSlotUnification(implSlot);
unificationGroup.SetDefiningMethod(implSlot);
}
}
continue;
}
if (!unificationGroup.IsInGroupOrIsDefiningSlot(declSlot))
{
if (unificationGroup.IsInGroupOrIsDefiningSlot(implSlot))
{
// Add decl to group.
// To do so, we need to have the Unification Group of the decl slot, as it may have multiple members itself
UnificationGroup addDeclGroup = new UnificationGroup(declSlot);
FindBaseUnificationGroup(baseType, addDeclGroup);
Debug.Assert(
addDeclGroup.IsInGroupOrIsDefiningSlot(declSlot) ||
(addDeclGroup.RequiresSlotUnification(declSlot) && addDeclGroup.DefiningMethod.Signature.EqualsWithCovariantReturnType(declSlot.Signature)));
foreach (MethodDesc methodImplRequiredToRemainInEffect in addDeclGroup.MethodsRequiringSlotUnification)
{
unificationGroup.AddMethodRequiringSlotUnification(methodImplRequiredToRemainInEffect);
}
// Add all members from the decl's unification group except for ones that have been seperated by name/sig matches
// or previously processed methodimpls. NOTE: This implies that method impls are order dependent.
if (separatedMethods == null || !separatedMethods.Contains(addDeclGroup.DefiningMethod))
{
unificationGroup.AddToGroup(addDeclGroup.DefiningMethod);
}
foreach (MethodDesc addDeclGroupMemberMethod in addDeclGroup.Members)
{
if (separatedMethods == null || !separatedMethods.Contains(addDeclGroupMemberMethod))
{
unificationGroup.AddToGroup(addDeclGroupMemberMethod);
}
}
if (unificationGroup.RequiresSlotUnification(declSlot))
{
unificationGroup.AddMethodRequiringSlotUnification(implSlot);
}
else if (implSlot == unificationGroup.DefiningMethod && implSlot.RequiresSlotUnification())
{
unificationGroup.AddMethodRequiringSlotUnification(declSlot);
unificationGroup.AddMethodRequiringSlotUnification(implSlot);
}
}
else if (unificationGroup.RequiresSlotUnification(declSlot))
{
if (implSlot.Signature.EqualsWithCovariantReturnType(unificationGroup.DefiningMethod.Signature))
{
unificationGroup.AddMethodRequiringSlotUnification(implSlot);
unificationGroup.SetDefiningMethod(implSlot);
}
}
}
}
}
