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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
using System;
using System.Collections.Generic;
using System.Diagnostics;
using Internal.Text;
using Internal.TypeSystem;
namespace ILCompiler.DependencyAnalysis
{
public class InterfaceDispatchMapNode : ObjectNode, ISymbolDefinitionNode, ISortableSymbolNode
{
TypeDesc _type;
public InterfaceDispatchMapNode(NodeFactory factory, TypeDesc type)
{
// Multidimensional arrays should not get a sealed vtable or a dispatch map. Runtime should use the
// sealed vtable and dispatch map of the System.Array basetype instead.
// Pointer arrays also follow the same path
Debug.Assert(!type.IsArrayTypeWithoutGenericInterfaces());
Debug.Assert(MightHaveInterfaceDispatchMap(type, factory));
_type = type;
}
protected override string GetName(NodeFactory factory) => this.GetMangledName(factory.NameMangler);
public void AppendMangledName(NameMangler nameMangler, Utf8StringBuilder sb)
{
sb.Append(nameMangler.CompilationUnitPrefix).Append("__InterfaceDispatchMap_").Append(nameMangler.SanitizeName(nameMangler.GetMangledTypeName(_type)));
}
public int Offset => 0;
public override bool IsShareable => false;
public override bool StaticDependenciesAreComputed => true;
public override ObjectNodeSection Section
{
get
{
if (_type.Context.Target.IsWindows)
return ObjectNodeSection.FoldableReadOnlyDataSection;
else
return ObjectNodeSection.DataSection;
}
}
protected override DependencyList ComputeNonRelocationBasedDependencies(NodeFactory factory)
{
var result = new DependencyList();
result.Add(factory.InterfaceDispatchMapIndirection(_type), "Interface dispatch map indirection node");
// VTable slots of implemented interfaces are consulted during emission
foreach (TypeDesc runtimeInterface in _type.RuntimeInterfaces)
{
result.Add(factory.VTable(runtimeInterface), "Interface for a dispatch map");
}
return result;
}
/// <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;
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.GetAllMethods();
foreach (MethodDesc slotMethod in slots)
{
MethodDesc declMethod = slotMethod;
if (interfaceOnDefinitionType != null)
declMethod = factory.TypeSystemContext.GetMethodForInstantiatedType(declMethod.GetTypicalMethodDefinition(), interfaceOnDefinitionType);
if (declMethod.Signature.IsStatic)
continue;
var implMethod = declType.GetTypeDefinition().ResolveInterfaceMethodToVirtualMethodOnType(declMethod);
if (implMethod != null)
return true;
}
}
return false;
}
void EmitDispatchMap(ref ObjectDataBuilder builder, NodeFactory factory)
{
var entryCountReservation = builder.ReserveInt();
int entryCount = 0;
TypeDesc declType = _type.GetClosestDefType();
// Catch any runtime interface collapsing. We shouldn't have any
Debug.Assert(declType.RuntimeInterfaces.Length == declType.GetTypeDefinition().RuntimeInterfaces.Length);
for (int interfaceIndex = 0; interfaceIndex < declType.RuntimeInterfaces.Length; interfaceIndex++)
{
var interfaceType = declType.RuntimeInterfaces[interfaceIndex];
var interfaceDefinitionType = declType.GetTypeDefinition().RuntimeInterfaces[interfaceIndex];
Debug.Assert(interfaceType.IsInterface);
IReadOnlyList<MethodDesc> virtualSlots = factory.VTable(interfaceType).Slots;
for (int interfaceMethodSlot = 0; interfaceMethodSlot < virtualSlots.Count; interfaceMethodSlot++)
{
MethodDesc declMethod = virtualSlots[interfaceMethodSlot];
if(!interfaceType.IsTypeDefinition)
declMethod = factory.TypeSystemContext.GetMethodForInstantiatedType(declMethod.GetTypicalMethodDefinition(), (InstantiatedType)interfaceDefinitionType);
var implMethod = declType.GetTypeDefinition().ResolveInterfaceMethodToVirtualMethodOnType(declMethod);
// Interface methods first implemented by a base type in the hierarchy will return null for the implMethod (runtime interface
// dispatch will walk the inheritance chain).
if (implMethod != null)
{
TypeDesc implType = declType;
while (!implType.HasSameTypeDefinition(implMethod.OwningType))
implType = implType.BaseType;
MethodDesc targetMethod = implMethod;
if (!implType.IsTypeDefinition)
targetMethod = factory.TypeSystemContext.GetMethodForInstantiatedType(implMethod.GetTypicalMethodDefinition(), (InstantiatedType)implType);
builder.EmitShort(checked((short)interfaceIndex));
builder.EmitShort(checked((short)(interfaceMethodSlot + (interfaceType.HasGenericDictionarySlot() ? 1 : 0))));
builder.EmitShort(checked((short)VirtualMethodSlotHelper.GetVirtualMethodSlot(factory, targetMethod, declType)));
entryCount++;
}
}
}
builder.EmitInt(entryCountReservation, entryCount);
}
public override ObjectData GetData(NodeFactory factory, bool relocsOnly = false)
{
ObjectDataBuilder objData = new ObjectDataBuilder(factory, relocsOnly);
objData.RequireInitialAlignment(16);
objData.AddSymbol(this);
if (!relocsOnly)
{
EmitDispatchMap(ref objData, factory);
}
return objData.ToObjectData();
}
public override int ClassCode => 848664602;
public override int CompareToImpl(ISortableNode other, CompilerComparer comparer)
{
return comparer.Compare(_type, ((InterfaceDispatchMapNode)other)._type);
}
}
}
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