// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
using System;
using System.Collections.Generic;
using System.Collections.Immutable;
using System.Diagnostics;
using System.Linq;
using System.Reflection;
using System.Threading;
using Microsoft.CodeAnalysis;
using Microsoft.CodeAnalysis.CSharp;
using Microsoft.CodeAnalysis.CSharp.Syntax;
using SourceGenerators;
namespace Microsoft.Interop
{
[Generator]
public sealed partial class ComInterfaceGenerator : IIncrementalGenerator
{
public void Initialize(IncrementalGeneratorInitializationContext context)
{
var stubEnvironment = context.CreateStubEnvironmentProvider();
// Get all types with the [GeneratedComInterface] attribute.
var attributedInterfaces = context.SyntaxProvider
.ForAttributeWithMetadataName(
TypeNames.GeneratedComInterfaceAttribute,
static (node, ct) => node is InterfaceDeclarationSyntax,
static (context, ct) => context.TargetSymbol is INamedTypeSymbol interfaceSymbol
? ((InterfaceDeclarationSyntax)context.TargetNode, interfaceSymbol)
: default)
.Collect()
.Combine(stubEnvironment)
.Select(
// Do all the work to get to the IncrementalComInterfaceContext in one step
// Intermediate results with symbols won't be incremental, and considering the overhead of setting up the incremental
// steps for projects that don't use the generator, we make this tradeoff.
static (input, ct) =>
{
if (input.Left.Length == 0)
{
return
(
InterfaceContexts: ImmutableArray<ComInterfaceContext>.Empty.ToSequenceEqual(),
MethodContexts: ImmutableArray<ComMethodContext>.Empty.ToSequenceEqual()
);
}
StubEnvironment stubEnvironment = input.Right;
List<(ComInterfaceInfo, INamedTypeSymbol)> interfaceInfos = new();
HashSet<(ComInterfaceInfo, INamedTypeSymbol)> externalIfaces = new(ComInterfaceInfo.EqualityComparerForExternalIfaces.Instance);
foreach (var (syntax, symbol) in input.Left)
{
var cii = ComInterfaceInfo.From(symbol, syntax, stubEnvironment, CancellationToken.None);
if (cii.HasValue)
interfaceInfos.Add(cii.Value);
var externalBase = ComInterfaceInfo.CreateInterfaceInfoForBaseInterfacesInOtherCompilations(symbol);
// Avoid adding duplicates if multiple interfaces derive from the same external interface.
if (!externalBase.IsDefaultOrEmpty)
{
foreach (var b in externalBase)
{
externalIfaces.Add(b);
}
}
}
interfaceInfos.AddRange(externalIfaces);
var comInterfaceContexts = ComInterfaceContext.GetContexts(interfaceInfos.Select(i => i.Item1).ToImmutableArray(), ct);
// Get all valid methods from all interfaces
Dictionary<ComMethodInfo, IMethodSymbol> methodSymbols = new();
List<List<ComMethodInfo>> methods = new();
foreach (var cii in interfaceInfos)
{
var cmi = ComMethodInfo.GetMethodsFromInterface(cii, ct);
var inner = new List<ComMethodInfo>();
foreach (var m in cmi)
{
if (m.HasValue)
{
inner.Add(m.Value.ComMethod);
methodSymbols.Add(m.Value.ComMethod, m.Value.Symbol);
}
}
methods.Add(inner);
}
List<(ComInterfaceContext, SequenceEqualImmutableArray<ComMethodInfo>)> ifaceCtxs = new();
for (int i = 0; i < interfaceInfos.Count; i++)
{
var cic = comInterfaceContexts[i];
if (cic.HasValue)
{
ifaceCtxs.Add((cic.Value, methods[i].ToSequenceEqualImmutableArray()));
}
}
var result = ComMethodContext.CalculateAllMethods(ifaceCtxs, ct);
List<ComMethodContext> methodContexts = new();
foreach (var data in result)
{
methodContexts.Add(new ComMethodContext(
data.Method,
data.OwningInterface,
CalculateStubInformation(
data.Method.MethodInfo.Syntax,
methodSymbols[data.Method.MethodInfo],
data.Method.Index,
stubEnvironment,
data.OwningInterface.Info,
ct)));
}
return
(
InterfaceContexts: ifaceCtxs.Select(x => x.Item1).Where(x => !x.IsExternallyDefined).ToSequenceEqualImmutableArray(),
MethodContexts: methodContexts.ToSequenceEqualImmutableArray()
);
});
// Create list of methods (inherited and declared) and their owning interface
var interfaceContextsToGenerate = attributedInterfaces.SelectMany(static (a, ct) => a.InterfaceContexts);
var comMethodContexts = attributedInterfaces.Select(static (a, ct) => a.MethodContexts);
var interfaceAndMethodsContexts = comMethodContexts
.Combine(interfaceContextsToGenerate.Collect())
.SelectMany(static (data, ct) =>
GroupComContextsForInterfaceGeneration(data.Left.Array, data.Right, ct));
var generatedInterfaces = interfaceAndMethodsContexts.Select(static (data, _) =>
{
ComInterfaceContext interfaceContext = data.Interface;
var writer = new IndentedTextWriter();
writer.WriteLine("// <auto-generated />");
writer.WriteLine("#pragma warning disable CS0612, CS0618, CS0649, CS1591"); // Suppress warnings about [Obsolete], "lack of assignment", and missing XML documentation in generated code.
// If the user has specified 'ManagedObjectWrapper', it means that the COM interface will never be used to marshal a native
// object as an RCW (eg. the IDIC vtable will also not be generated, nor any additional supporting code). To reduce binary
// size, we're not emitting the interface methods on the implementation interface that has '[DynamicInterfaceCastableImplementation]'
// on it. However, doing so will cause the CA2256 warning to be produced. We can't remove the attribute, as that would cause
// the wrong exception to be thrown when trying an IDIC cast with this interface (not 'InvalidCastException'). Because this is
// a niche scenario, and we don't want to regress perf or size, we can just disable the warning instead.
if (interfaceContext.Options is ComInterfaceOptions.ManagedObjectWrapper)
{
writer.WriteLine("#pragma warning disable CA2256");
}
writer.WriteLine();
WriteImplementationVTableStruct(writer, data);
writer.WriteLine();
WriteInterfaceInformation(writer, interfaceContext.Info);
writer.WriteLine();
WriteInterfaceImplementation(writer, data);
writer.WriteLine();
WriteIUnknownDerivedOriginalInterfacePart(writer, data);
// Identifier escape markers belong in declarations, but are not valid in hint names.
return (HintName: interfaceContext.Info.Type.FullTypeName.Replace(TypeNames.GlobalAlias, "").Replace("@", ""), Source: writer.ToString());
}).WithTrackingName("GeneratedComInterface");
context.RegisterSourceOutput(generatedInterfaces, static (context, data) => context.AddSource(data.HintName, data.Source));
}
private static bool IsHResultLikeType(ManagedTypeInfo type)
{
string typeName = type.FullTypeName.Split('.', ':')[^1];
return typeName.Equals("hr", StringComparison.OrdinalIgnoreCase)
|| typeName.Equals("hresult", StringComparison.OrdinalIgnoreCase);
}
/// <summary>
/// Calculates the shared information needed for both source-available and sourceless stub generation.
/// </summary>
private static IncrementalMethodStubGenerationContext CalculateSharedStubInformation(
IMethodSymbol symbol,
int index,
StubEnvironment environment,
ISignatureDiagnosticLocations diagnosticLocations,
ComInterfaceInfo owningInterfaceInfo,
CancellationToken ct)
{
ct.ThrowIfCancellationRequested();
INamedTypeSymbol? lcidConversionAttrType = environment.LcidConversionAttrType;
INamedTypeSymbol? suppressGCTransitionAttrType = environment.SuppressGCTransitionAttrType;
INamedTypeSymbol? unmanagedCallConvAttrType = environment.UnmanagedCallConvAttrType;
// Get any attributes of interest on the method
AttributeData? lcidConversionAttr = null;
AttributeData? suppressGCTransitionAttribute = null;
AttributeData? unmanagedCallConvAttribute = null;
foreach (AttributeData attr in symbol.GetAttributes())
{
if (lcidConversionAttrType is not null && SymbolEqualityComparer.Default.Equals(attr.AttributeClass, lcidConversionAttrType))
{
lcidConversionAttr = attr;
}
else if (suppressGCTransitionAttrType is not null && SymbolEqualityComparer.Default.Equals(attr.AttributeClass, suppressGCTransitionAttrType))
{
suppressGCTransitionAttribute = attr;
}
else if (unmanagedCallConvAttrType is not null && SymbolEqualityComparer.Default.Equals(attr.AttributeClass, unmanagedCallConvAttrType))
{
unmanagedCallConvAttribute = attr;
}
}
var generatorDiagnostics = new GeneratorDiagnosticsBag(new DiagnosticDescriptorProvider(), diagnosticLocations, SR.ResourceManager, typeof(FxResources.Microsoft.Interop.ComInterfaceGenerator.SR));
if (lcidConversionAttr is not null)
{
// Using LCIDConversion with source-generated interop is not supported
generatorDiagnostics.ReportConfigurationNotSupported(lcidConversionAttr, nameof(TypeNames.LCIDConversionAttribute));
}
GeneratedComInterfaceCompilationData.TryGetGeneratedComInterfaceAttributeFromInterface(symbol.ContainingType, out var generatedComAttribute);
var generatedComInterfaceAttributeData = GeneratedComInterfaceCompilationData.GetDataFromAttribute(generatedComAttribute);
bool preserveSig = symbol.MethodImplementationFlags.HasFlag(MethodImplAttributes.PreserveSig);
ErrorHandlingInfo? errorHandlingInfo = preserveSig
? null
: new ErrorHandlingInfo(
SpecialTypeInfo.Int32,
new ManagedHResultExceptionMarshallingInfo(owningInterfaceInfo.InterfaceId),
ErrorHandlingLocation.HiddenReturnValue);
// Create the stub.
var signatureContext = SignatureContext.Create(
symbol,
DefaultMarshallingInfoParser.Create(
environment,
generatorDiagnostics,
symbol,
generatedComInterfaceAttributeData,
generatedComAttribute),
environment,
new CodeEmitOptions(SkipInit: true),
typeof(ComInterfaceGenerator).Assembly,
errorHandlingInfo);
if (!preserveSig)
{
TypePositionInfo? managedReturnInfo = signatureContext.ElementTypeInformation.FirstOrDefault(e => e.IsManagedReturnPosition);
if (managedReturnInfo is not null
&& ((managedReturnInfo.ManagedType is SpecialTypeInfo { SpecialType: SpecialType.System_Int32 or SpecialType.System_Enum } or EnumTypeInfo
&& managedReturnInfo.MarshallingAttributeInfo.Equals(NoMarshallingInfo.Instance))
|| IsHResultLikeType(managedReturnInfo.ManagedType)))
{
generatorDiagnostics.ReportDiagnostic(DiagnosticInfo.Create(GeneratorDiagnostics.ComMethodManagedReturnWillBeOutVariable, symbol.Locations[0]));
}
}
else
{
// If our method is PreserveSig, we will notify the user if they are returning a type that may be an HRESULT type
// that is defined as a structure. These types used to work with built-in COM interop, but they do not work with
// source-generated interop as we now use the MemberFunction calling convention, which is more correct.
TypePositionInfo? managedReturnInfo = signatureContext.ElementTypeInformation.FirstOrDefault(e => e.IsManagedReturnPosition);
if (managedReturnInfo is { MarshallingAttributeInfo: UnmanagedBlittableMarshallingInfo, ManagedType: ValueTypeInfo valueType }
&& IsHResultLikeType(valueType))
{
generatorDiagnostics.ReportDiagnostic(DiagnosticInfo.Create(
GeneratorDiagnostics.HResultTypeWillBeTreatedAsStruct,
symbol.Locations[0],
ImmutableDictionary<string, string>.Empty.Add(GeneratorDiagnosticProperties.AddMarshalAsAttribute, "Error"),
valueType.DiagnosticFormattedName));
}
}
var direction = GetDirectionFromOptions(generatedComInterfaceAttributeData.Options);
// Ensure the size of collections are known at marshal / unmarshal in time.
// A collection that is marshalled in cannot have a size that is an 'out' parameter.
foreach (TypePositionInfo parameter in signatureContext.ManagedParameters)
{
MarshallerHelpers.ValidateCountInfoAvailableAtCall(
direction,
parameter,
generatorDiagnostics,
symbol,
GeneratorDiagnostics.SizeOfInCollectionMustBeDefinedAtCallOutParam,
GeneratorDiagnostics.SizeOfInCollectionMustBeDefinedAtCallReturnValue);
}
ImmutableArray<string> callConv = VirtualMethodPointerStubGenerator.GetCallingConventionsFromAttributes(
suppressGCTransitionAttribute,
unmanagedCallConvAttribute,
ImmutableArray.Create("MemberFunction"));
var declaringType = ManagedTypeInfo.CreateTypeInfoForTypeSymbol(symbol.ContainingType);
MarshallingInfo exceptionMarshallingInfo;
if (generatedComInterfaceAttributeData.ExceptionToUnmanagedMarshaller is null)
{
exceptionMarshallingInfo = new ComExceptionMarshalling();
}
else
{
exceptionMarshallingInfo = CustomMarshallingInfoHelper.CreateNativeMarshallingInfoForNonSignatureElement(
environment.Compilation.GetTypeByMetadataName(TypeNames.System_Exception),
(INamedTypeSymbol)generatedComInterfaceAttributeData.ExceptionToUnmanagedMarshaller,
generatedComAttribute,
environment.Compilation,
generatorDiagnostics);
}
return new IncrementalMethodStubGenerationContext(
signatureContext,
diagnosticLocations,
callConv.ToSequenceEqual(),
new VirtualMethodIndexData(index, ImplicitThisParameter: true, direction, true, ExceptionMarshalling.Com),
exceptionMarshallingInfo,
environment.EnvironmentFlags,
owningInterfaceInfo.Type,
declaringType,
generatorDiagnostics.Diagnostics.ToSequenceEqualImmutableArray(),
ComInterfaceDispatchMarshallingInfo.Instance,
ClassifyMemberKind(symbol));
}
private static StubMemberKind ClassifyMemberKind(IMethodSymbol symbol) => (symbol.MethodKind, symbol.AssociatedSymbol) switch
{
(MethodKind.PropertyGet, IPropertySymbol { IsIndexer: true }) => StubMemberKind.IndexerGetter,
(MethodKind.PropertySet, IPropertySymbol { IsIndexer: true }) => StubMemberKind.IndexerSetter,
(MethodKind.PropertyGet, _) => StubMemberKind.PropertyGetter,
(MethodKind.PropertySet, _) => StubMemberKind.PropertySetter,
_ => StubMemberKind.Method,
};
internal static IncrementalMethodStubGenerationContext CalculateStubInformation(MemberDeclarationSyntax? syntax, IMethodSymbol symbol, int index, StubEnvironment environment, ComInterfaceInfo owningInterface, CancellationToken ct)
{
ISignatureDiagnosticLocations locations = syntax switch
{
null => NoneSignatureDiagnosticLocations.Instance,
MethodDeclarationSyntax methodSyntax => new MethodSignatureDiagnosticLocations(methodSyntax),
PropertyDeclarationSyntax propertySyntax => CreatePropertyAccessorDiagnosticLocations(propertySyntax, symbol),
IndexerDeclarationSyntax indexerSyntax => CreateIndexerAccessorDiagnosticLocations(indexerSyntax, symbol),
_ => throw new UnreachableException(),
};
var sourcelessStubInformation = CalculateSharedStubInformation(
symbol,
index,
environment,
locations,
owningInterface,
ct);
if (syntax is null)
return sourcelessStubInformation;
ContainingSyntaxContext containingSyntaxContext = syntax.GetContainingSyntaxContext();
DeclarationHeader methodSyntaxTemplate = syntax switch
{
MethodDeclarationSyntax methodSyntax => new DeclarationHeader(
ContainingTypeUtilities.GetModifiers(methodSyntax.Modifiers)
.Where(static modifier => modifier is not ("new" or "partial" or "virtual" or "public" or "private" or "protected" or "internal"))
.ToImmutableArray(),
"",
CodeWriterHelpers.EscapeIdentifier(symbol.Name)),
// Property / indexer accessors are emitted as plain methods named e.g. 'get_Foo' / 'set_Foo'
// ('get_Item' / 'set_Item' for indexers, or the [IndexerName]-renamed value).
PropertyDeclarationSyntax or IndexerDeclarationSyntax => new DeclarationHeader(
ImmutableArray<string>.Empty,
"",
symbol.Name),
_ => throw new UnreachableException(),
};
StubMemberKind memberKind = ClassifyMemberKind(symbol);
return new SourceAvailableIncrementalMethodStubGenerationContext(
sourcelessStubInformation.SignatureContext,
containingSyntaxContext,
methodSyntaxTemplate,
locations,
sourcelessStubInformation.CallingConvention,
sourcelessStubInformation.VtableIndexData,
sourcelessStubInformation.ExceptionMarshallingInfo,
sourcelessStubInformation.EnvironmentFlags,
sourcelessStubInformation.TypeKeyOwner,
sourcelessStubInformation.DeclaringType,
sourcelessStubInformation.Diagnostics,
ComInterfaceDispatchMarshallingInfo.Instance,
memberKind);
}
// For a property accessor, the user-visible source location is the property's identifier.
// The getter has no managed parameters; the setter has the implicit 'value' parameter which we report at
// the property identifier (it has no source location of its own).
private static MethodSignatureDiagnosticLocations CreatePropertyAccessorDiagnosticLocations(PropertyDeclarationSyntax propertySyntax, IMethodSymbol accessor)
{
Location identifierLocation = propertySyntax.Identifier.GetLocation();
ImmutableArray<Location> parameterLocations = accessor.MethodKind is MethodKind.PropertySet
? ImmutableArray.Create(identifierLocation)
: ImmutableArray<Location>.Empty;
return new MethodSignatureDiagnosticLocations(accessor.Name, parameterLocations, identifierLocation);
}
// For an indexer accessor, the user-visible source location is the 'this' keyword (indexers have no
// identifier token). Diagnostics that index into ManagedParameterLocations must see one entry per
// index parameter, plus the implicit 'value' parameter for the setter, with 'value' falling back to
// the 'this' location since it has no syntactic representation.
private static MethodSignatureDiagnosticLocations CreateIndexerAccessorDiagnosticLocations(IndexerDeclarationSyntax indexerSyntax, IMethodSymbol accessor)
{
Location thisLocation = indexerSyntax.ThisKeyword.GetLocation();
var indexParameters = indexerSyntax.ParameterList.Parameters;
int parameterCount = accessor.MethodKind is MethodKind.PropertySet
? indexParameters.Count + 1
: indexParameters.Count;
var builder = ImmutableArray.CreateBuilder<Location>(parameterCount);
foreach (var parameter in indexParameters)
{
builder.Add(parameter.GetLocation());
}
if (accessor.MethodKind is MethodKind.PropertySet)
{
builder.Add(thisLocation);
}
return new MethodSignatureDiagnosticLocations(accessor.Name, builder.MoveToImmutable(), thisLocation);
}
private static MarshalDirection GetDirectionFromOptions(ComInterfaceOptions options)
{
if (options.HasFlag(ComInterfaceOptions.ManagedObjectWrapper | ComInterfaceOptions.ComObjectWrapper))
{
return MarshalDirection.Bidirectional;
}
if (options.HasFlag(ComInterfaceOptions.ManagedObjectWrapper))
{
return MarshalDirection.UnmanagedToManaged;
}
if (options.HasFlag(ComInterfaceOptions.ComObjectWrapper))
{
return MarshalDirection.ManagedToUnmanaged;
}
throw new ArgumentOutOfRangeException(nameof(options), "No-wrapper options should have been filtered out before calling this method.");
}
private static ImmutableArray<ComInterfaceAndMethodsContext> GroupComContextsForInterfaceGeneration(ImmutableArray<ComMethodContext> methods, ImmutableArray<ComInterfaceContext> interfaces, CancellationToken ct)
{
ct.ThrowIfCancellationRequested();
// We can end up with an empty set of contexts here as the compiler will call a SelectMany
// after a Collect with no input entries
if (interfaces.IsEmpty)
{
return ImmutableArray<ComInterfaceAndMethodsContext>.Empty;
}
// Due to how the source generator driver processes the input item tables and our limitation that methods on COM interfaces can only be defined in a single partial definition of the type,
// we can guarantee that, if the interface contexts are in order of I1, I2, I3, I4..., then then method contexts are ordered as follows:
// - I1.M1
// - I1.M2
// - I1.M3
// - I2.M1
// - I2.M2
// - I2.M3
// - I4.M1 (I3 had no methods)
// - etc...
// This enable us to group our contexts by their containing syntax rather simply.
var contextList = ImmutableArray.CreateBuilder<ComInterfaceAndMethodsContext>();
int methodIndex = 0;
foreach (var iface in interfaces)
{
var methodList = ImmutableArray.CreateBuilder<ComMethodContext>();
while (methodIndex < methods.Length && methods[methodIndex].OwningInterface == iface)
{
var method = methods[methodIndex];
if (method.MethodInfo.IsUserDefinedShadowingMethod)
{
bool shadowFound = false;
int shadowIndex = -1;
// Don't remove method, but make it so that it doesn't generate any stubs
for (int i = methodList.Count - 1; i > -1; i--)
{
var potentialShadowedMethod = methodList[i];
if (MethodEquals(method, potentialShadowedMethod))
{
shadowFound = true;
shadowIndex = i;
break;
}
}
if (shadowFound)
{
methodList[shadowIndex].IsHiddenOnDerivedInterface = true;
}
// We might not find the shadowed method if it's defined on a non-GeneratedComInterface-attributed interface. Thats okay and we can disregard it.
}
methodList.Add(methods[methodIndex++]);
}
contextList.Add(new(iface, methodList.ToImmutable().ToSequenceEqual()));
}
return contextList.ToImmutable();
static bool MethodEquals(ComMethodContext a, ComMethodContext b)
{
if (a.MethodInfo.MethodName != b.MethodInfo.MethodName)
return false;
if (a.GenerationContext.SignatureContext.ManagedParameters.SequenceEqual(b.GenerationContext.SignatureContext.ManagedParameters))
return true;
return false;
}
}
private static void WriteImplementationVTableStruct(IndentedTextWriter writer, ComInterfaceAndMethodsContext interfaceMethods)
{
writer.WriteLine("[global::System.Runtime.InteropServices.StructLayoutAttribute(global::System.Runtime.InteropServices.LayoutKind.Sequential)]");
// The 'unsafe' modifier goes on each field rather than on the type: a field-level modifier makes the
// pointer legal to name under the legacy rules and has a meaning under the updated ones, whereas a
// type-level modifier is meaningless under the updated rules and warns (CS9377).
writer.WriteLine("file struct InterfaceImplementationVtable");
writer.WriteLine('{');
writer.Indent++;
writer.WriteLine("public unsafe delegate* unmanaged[MemberFunction]<void*, global::System.Guid*, void**, int> QueryInterface_0;");
writer.WriteLine("public unsafe delegate* unmanaged[MemberFunction]<void*, uint> AddRef_1;");
writer.WriteLine("public unsafe delegate* unmanaged[MemberFunction]<void*, uint> Release_2;");
if (interfaceMethods.Interface.Base is not null)
{
foreach (ComMethodContext inheritedMethod in interfaceMethods.InheritedMethods)
{
string functionPointerType = VirtualMethodPointerStubGenerator.GenerateUnmanagedFunctionPointerTypeForMethod(
inheritedMethod.GenerationContext,
ComInterfaceGeneratorHelpers.GetGeneratorResolver);
writer.WriteLine($"public unsafe {functionPointerType} {inheritedMethod.MethodInfo.MethodName}_{inheritedMethod.GenerationContext.VtableIndexData.Index};");
}
}
foreach (ComMethodContext declaredMethod in
interfaceMethods.DeclaredMethods
.Where(context => context.UnmanagedToManagedStub.Diagnostics.All(diag => diag.Descriptor.DefaultSeverity != DiagnosticSeverity.Error)))
{
string functionPointerType = VirtualMethodPointerStubGenerator.GenerateUnmanagedFunctionPointerTypeForMethod(
declaredMethod.GenerationContext,
ComInterfaceGeneratorHelpers.GetGeneratorResolver);
writer.WriteLine($"public unsafe {functionPointerType} {declaredMethod.MethodInfo.MethodName}_{declaredMethod.GenerationContext.VtableIndexData.Index};");
}
writer.Indent--;
writer.WriteLine('}');
}
private static void WriteInterfaceInformation(IndentedTextWriter writer, ComInterfaceInfo interfaceInfo)
{
writer.WriteLine("file sealed class InterfaceInformation : global::System.Runtime.InteropServices.Marshalling.IIUnknownInterfaceType");
writer.WriteLine('{');
writer.Indent++;
writer.WriteLine($"public static global::System.Guid Iid {{ get; }} = new({ComInterfaceGeneratorHelpers.CreateEmbeddedDataBlobExpression(interfaceInfo.InterfaceId.ToByteArray())});");
// The modifier makes the pointer type legal to name; the accessor still needs an unsafe context of
// its own, since under the updated rules a member modifier opens none for the body.
writer.WriteLine("public static unsafe void** ManagedVirtualMethodTable");
writer.WriteLine('{');
writer.Indent++;
writer.WriteLine("get");
writer.WriteLine('{');
writer.Indent++;
writer.WriteLine("unsafe");
writer.WriteLine('{');
writer.Indent++;
writer.WriteLine($"return {(interfaceInfo.Options.HasFlag(ComInterfaceOptions.ManagedObjectWrapper) ? "(void**)global::System.Runtime.CompilerServices.Unsafe.AsPointer(in InterfaceImplementation.Vtable)" : "null")};");
writer.Indent--;
writer.WriteLine('}');
writer.Indent--;
writer.WriteLine('}');
writer.Indent--;
writer.WriteLine('}');
writer.Indent--;
writer.WriteLine('}');
}
private static void WriteInterfaceImplementation(IndentedTextWriter writer, ComInterfaceAndMethodsContext data)
{
writer.WriteLine("[global::System.Runtime.InteropServices.DynamicInterfaceCastableImplementationAttribute]");
// This type holds the stubs that explicitly implement the user's interface members. Those stubs copy
// their modifiers from the user's declaration and cannot be marked 'unsafe' on their own without
// failing to implement a safe member (CS9366), so under the legacy rules the type modifier is what
// makes their pointer parameters legal to name.
string unsafeModifier = data.Interface.Info.UseUpdatedMemorySafetyRules ? "" : "unsafe ";
writer.WriteLine($"file {unsafeModifier}interface InterfaceImplementation : {data.Interface.Info.Type.FullTypeName}");
writer.WriteLine('{');
writer.Indent++;
if (data.Interface.Options.HasFlag(ComInterfaceOptions.ManagedObjectWrapper))
{
writer.WriteLine("[global::System.Runtime.CompilerServices.FixedAddressValueTypeAttribute]");
writer.WriteLine("public static readonly InterfaceImplementationVtable Vtable;");
writer.WriteLine();
writer.WriteLine("static InterfaceImplementation()");
writer.WriteLine('{');
writer.Indent++;
// The initialization takes addresses and writes through pointers, so it opens its own unsafe
// context rather than relying on one from the containing type.
writer.WriteLine("unsafe");
writer.WriteLine('{');
writer.Indent++;
if (data.Interface.Base is { } baseInterface)
{
writer.WriteLine("global::System.Runtime.InteropServices.NativeMemory.Copy(");
writer.Indent++;
writer.WriteLine($"global::System.Runtime.InteropServices.Marshalling.StrategyBasedComWrappers.DefaultIUnknownInterfaceDetailsStrategy.GetIUnknownDerivedDetails(typeof({baseInterface.Info.Type.FullTypeName}).TypeHandle).ManagedVirtualMethodTable,");
writer.WriteLine("global::System.Runtime.CompilerServices.Unsafe.AsPointer(ref Vtable),");
writer.WriteLine($"(nuint)(sizeof(void*) * {data.BaseVTableSize}));");
writer.Indent--;
}
else
{
// If we don't have a base interface, we need to manually fill in the base IUnknown slots.
writer.WriteLine("global::System.Runtime.InteropServices.ComWrappers.GetIUnknownImpl(");
writer.Indent++;
writer.WriteLine("out *(nint*)&((InterfaceImplementationVtable*)global::System.Runtime.CompilerServices.Unsafe.AsPointer(ref Vtable))->QueryInterface_0,");
writer.WriteLine("out *(nint*)&((InterfaceImplementationVtable*)global::System.Runtime.CompilerServices.Unsafe.AsPointer(ref Vtable))->AddRef_1,");
writer.WriteLine("out *(nint*)&((InterfaceImplementationVtable*)global::System.Runtime.CompilerServices.Unsafe.AsPointer(ref Vtable))->Release_2);");
writer.Indent--;
}
writer.WriteLine();
foreach (ComMethodContext declaredMethodContext in data.DeclaredMethods
.Where(context => context.UnmanagedToManagedStub.Diagnostics.All(diag => diag.Descriptor.DefaultSeverity != DiagnosticSeverity.Error)))
{
writer.WriteLine($"Vtable.{declaredMethodContext.MethodInfo.MethodName}_{declaredMethodContext.GenerationContext.VtableIndexData.Index} = &{((SourceAvailableIncrementalMethodStubGenerationContext)declaredMethodContext.GenerationContext).AbiMethodIdentifier};");
}
writer.Indent--;
writer.WriteLine('}');
writer.Indent--;
writer.WriteLine('}');
}
string derivedInterfaceName = data.Interface.Info.Type.FullTypeName;
(GeneratedComMember Member, string ExplicitInterface)? bufferedDeclaredGetter = null;
foreach (ComMethodContext declaredMethod in data.DeclaredMethods)
{
if (declaredMethod.ManagedToUnmanagedStub is GeneratedStubCodeContext managedToUnmanagedContext)
{
EmitMemberHonoringPropertyMerge(writer, managedToUnmanagedContext.Stub, derivedInterfaceName, ref bufferedDeclaredGetter);
}
if (declaredMethod.UnmanagedToManagedStub is GeneratedStubCodeContext unmanagedToManagedContext &&
unmanagedToManagedContext.Diagnostics.All(static d => d.Descriptor.DefaultSeverity != DiagnosticSeverity.Error))
{
writer.WriteLine();
unmanagedToManagedContext.Stub.WriteTo(writer);
}
}
FlushBufferedPropertyGetter(writer, ref bufferedDeclaredGetter);
(GeneratedComMember Member, string ExplicitInterface)? bufferedShadowGetter = null;
foreach (ComMethodContext inheritedStub in data.InheritedMethods)
{
if (inheritedStub is not { IsExternallyDefined: false, ManagedToUnmanagedStub: GeneratedStubCodeContext shadowImplementationContextContext })
{
continue;
}
EmitMemberHonoringPropertyMerge(writer, shadowImplementationContextContext.Stub, derivedInterfaceName, ref bufferedShadowGetter);
}
FlushBufferedPropertyGetter(writer, ref bufferedShadowGetter);
(GeneratedComMember Member, string ExplicitInterface)? bufferedUnreachableGetter = null;
foreach (ComMethodContext inheritedStub in data.InheritedMethods)
{
if (inheritedStub.IsExternallyDefined)
{
continue;
}
EmitMemberHonoringPropertyMerge(
writer,
CreateUnreachableInheritedMember(inheritedStub),
inheritedStub.OriginalDeclaringInterface.Info.Type.FullTypeName,
ref bufferedUnreachableGetter);
}
FlushBufferedPropertyGetter(writer, ref bufferedUnreachableGetter);
writer.Indent--;
writer.WriteLine('}');
}
private static void EmitMemberHonoringPropertyMerge(
IndentedTextWriter writer,
GeneratedComMember member,
string explicitInterface,
ref (GeneratedComMember Member, string ExplicitInterface)? bufferedGetter)
{
// Property and indexer accessor stubs arrive one per accessor (get then set when both exist).
// An explicit implementation must combine matching halves into a single declaration.
if (member.Kind.IsPropertyOrIndexerAccessor())
{
if (!member.Kind.IsAccessorSetter())
{
FlushBufferedPropertyGetter(writer, ref bufferedGetter);
bufferedGetter = (member, explicitInterface);
return;
}
if (bufferedGetter is { } getter
&& getter.ExplicitInterface == explicitInterface
&& getter.Member.HasSameAccessorTarget(member))
{
writer.WriteLine();
getter.Member.WriteTo(writer, explicitInterface, member);
bufferedGetter = null;
return;
}
}
FlushBufferedPropertyGetter(writer, ref bufferedGetter);
writer.WriteLine();
member.WriteTo(writer, explicitInterface);
}
private static GeneratedComMember CreateUnreachableInheritedMember(ComMethodContext inheritedStub)
{
IncrementalMethodStubGenerationContext genCtx = inheritedStub.GenerationContext;
string name = genCtx.MemberKind.IsPropertyOrIndexerAccessor()
? IncrementalMethodStubGenerationContext.GetPropertyNameFromAccessor(inheritedStub.MethodInfo.MethodName)
: inheritedStub.MethodInfo.MethodName;
return new GeneratedComMember(
genCtx.MemberKind,
CodeWriterHelpers.EscapeIdentifier(name),
VirtualMethodPointerStubGenerator.GetManagedSignature(genCtx),
ImmutableArray<string>.Empty.ToSequenceEqual(),
"throw new global::System.Diagnostics.UnreachableException()",
IsExpressionBody: true);
}
private static void FlushBufferedPropertyGetter(IndentedTextWriter writer, ref (GeneratedComMember Member, string ExplicitInterface)? bufferedGetter)
{
if (bufferedGetter is not { } getter)
{
return;
}
writer.WriteLine();
getter.Member.WriteTo(writer, getter.ExplicitInterface);
bufferedGetter = null;
}
private static void WriteIUnknownDerivedOriginalInterfacePart(IndentedTextWriter writer, ComInterfaceAndMethodsContext data)
{
data.Interface.Info.TypeDefinitionContext.WriteToWithUnsafeModifier(data.Interface.Info.UseUpdatedMemorySafetyRules, writer, (data.Interface.Info.ContainingSyntax, data.ShadowingMethods, data.Interface.Info.UseUpdatedMemorySafetyRules), static (writer, data) =>
{
(DeclarationHeader syntax, IEnumerable<ComMethodContext>? shadowingMethods, bool useUpdatedMemorySafetyRules) = data;
writer.WriteLine("[global::System.Runtime.InteropServices.Marshalling.IUnknownDerivedAttribute<InterfaceInformation, InterfaceImplementation>]");
ImmutableArray<string> typeModifiers = useUpdatedMemorySafetyRules
? syntax.Modifiers
: CodeWriterHelpers.AddModifier(syntax.Modifiers, "unsafe");
writer.WriteLine($"{string.Join(" ", typeModifiers)} {syntax.Keyword} {syntax.Name}");
writer.WriteLine('{');
writer.Indent++;
// Buffered getter state for merging consecutive get+set pairs into one declaration.
// For ordinary properties IndexParamList / IndexArgList are null; for indexers they hold
// the formatted parameter list (e.g. "int i, string s") and the argument-forwarding list
// (e.g. "i, s") respectively. The parameter list also serves as part of the merge identity
// so that overloaded indexers do not accidentally cross-pair.
(string? PropName, string? DeclaringType, string? PropType,
SequenceEqualImmutableArray<AttributeInfo> PropAttrs,
string? IndexParamList, string? IndexArgList, bool IsUnsafe) pendingGetter = default;
foreach (ComMethodContext shadow in shadowingMethods)
{
IncrementalMethodStubGenerationContext generationContext = shadow.GenerationContext;
SignatureContext sigContext = generationContext.SignatureContext;
// A shadow forwards to a member of the base interface. When that member declares itself
// caller-unsafe the shadow has to say the same thing, or it would silently widen the
// contract and its implementation could no longer implement it, and the forwarding call
// needs an unsafe context of its own.
bool isUnsafe = shadow.MethodInfo.Syntax is { } shadowedSyntax
&& shadowedSyntax.Modifiers.Any(SyntaxKind.UnsafeKeyword);
if (generationContext.MemberKind.IsPropertyOrIndexerAccessor())
{
bool isSetter = generationContext.MemberKind.IsAccessorSetter();
bool isIndexer = generationContext.MemberKind.IsIndexerAccessor();
string accessorName = shadow.MethodInfo.MethodName;
string propName = CodeWriterHelpers.EscapeIdentifier(IncrementalMethodStubGenerationContext.GetPropertyNameFromAccessor(accessorName));
string declaringType = shadow.OriginalDeclaringInterface.Info.Type.FullTypeName;
// Materialize the parameter sequences once — StubParameters / ManagedParameters
// are IEnumerable<T>, not lists.
ImmutableArray<GeneratedParameter> stubParams = sigContext.StubParameters.ToImmutableArray();
ImmutableArray<TypePositionInfo> managedParams = sigContext.ManagedParameters.ToImmutableArray();
// The value type for an accessor is the StubReturnType for a getter and the LAST
// managed parameter type for a setter (the implicit 'value'). For both ordinary
// properties (one managed parameter) and indexer setters (index params + value),
// the value entry is always last.
string propType = isSetter
? stubParams[stubParams.Length - 1].Type
: sigContext.StubReturnType;
SequenceEqualImmutableArray<AttributeInfo> propAttrs = shadow.MethodInfo.AssociatedAttributes;
string? indexParamList = null;
string? indexArgList = null;
if (isIndexer)
{
// For indexers the index parameter list is the StubParameters minus the
// implicit value entry (for setters). For getters, all StubParameters are
// index parameters.
int indexCount = isSetter ? stubParams.Length - 1 : stubParams.Length;
indexParamList = string.Join(", ", stubParams.Take(indexCount));
indexArgList = string.Join(", ", managedParams.Take(indexCount).Select(mp => $"{(mp.IsByRef ? $"{MarshallerHelpers.GetManagedArgumentRefKindKeyword(mp)} " : "")}{mp.InstanceIdentifier}"));
}
if (!isSetter)
{
FlushPendingGetter(writer, ref pendingGetter);
pendingGetter = (propName, declaringType, propType, propAttrs, indexParamList, indexArgList, isUnsafe);
continue;
}
// Setter: try to pair with a buffered getter. Identity includes the index parameter
// list so overloaded indexers (same name, different param types) stay separate.
if (pendingGetter.PropName == propName
&& pendingGetter.DeclaringType == declaringType
&& pendingGetter.IndexParamList == indexParamList)
{
EmitPropertyAttributes(writer, pendingGetter.PropAttrs);
EmitDeclarationHead(writer, pendingGetter.PropType!, pendingGetter.PropName!, pendingGetter.IndexParamList, pendingGetter.IsUnsafe || isUnsafe);
writer.WriteLine('{');
writer.Indent++;
EmitAccessor(writer, isSetter: false, pendingGetter.DeclaringType!, pendingGetter.PropName!, pendingGetter.IndexArgList, pendingGetter.IsUnsafe);
EmitAccessor(writer, isSetter: true, pendingGetter.DeclaringType!, pendingGetter.PropName!, pendingGetter.IndexArgList, isUnsafe);
writer.Indent--;
writer.WriteLine('}');
pendingGetter = default;
continue;
}
FlushPendingGetter(writer, ref pendingGetter);
EmitPropertyAttributes(writer, propAttrs);
EmitDeclarationHead(writer, propType, propName, indexParamList, isUnsafe);
writer.WriteLine('{');
writer.Indent++;
EmitAccessor(writer, isSetter: true, declaringType, propName, indexArgList, isUnsafe);
writer.Indent--;
writer.WriteLine('}');
continue;
}
FlushPendingGetter(writer, ref pendingGetter);
// AssociatedAttributes is currently populated only for property/indexer accessors;
// ordinary method stubs must not carry any. If this fires, a new producer is feeding
// the field for a non-property member and the emitter needs to decide how to consume it.
Debug.Assert(shadow.MethodInfo.AssociatedAttributes.Array.IsEmpty);
foreach (string additionalAttr in sigContext.AdditionalAttributes)
{
writer.WriteLine($"[{additionalAttr}]");
}
foreach (AttributeInfo attrInfo in shadow.MethodInfo.Attributes)
{
writer.WriteLine($"[{attrInfo.Type}({string.Join(", ", attrInfo.Arguments)})]");
}
string methodName = CodeWriterHelpers.EscapeIdentifier(shadow.MethodInfo.MethodName);
writer.Write($"new {(isUnsafe ? "unsafe " : "")}{sigContext.StubReturnType} {methodName}");
writer.Write($"({string.Join(", ", sigContext.StubParameters)})");
string forwardingCall = $"(({shadow.OriginalDeclaringInterface.Info.Type.FullTypeName})this).{methodName}"
+ $"({string.Join(", ", sigContext.ManagedParameters.Select(mp => $"{(mp.IsByRef ? $"{MarshallerHelpers.GetManagedArgumentRefKindKeyword(mp)} " : "")}{mp.InstanceIdentifier}"))})";
if (isUnsafe)
{
// An expression body cannot host the required unsafe context: the 'unsafe(...)'
// expression form is not one of the forms a statement may consist of.
bool returnsVoid = sigContext.StubReturnType == "void";
writer.WriteLine();
writer.WriteLine('{');
writer.Indent++;
writer.WriteLine("unsafe");
writer.WriteLine('{');
writer.Indent++;
writer.WriteLine($"{(returnsVoid ? "" : "return ")}{forwardingCall};");
writer.Indent--;
writer.WriteLine('}');
writer.Indent--;
writer.WriteLine('}');
}
else
{
writer.WriteLine($" => {forwardingCall};");
}
}
FlushPendingGetter(writer, ref pendingGetter);
writer.Indent--;
writer.WriteLine('}');
static void FlushPendingGetter(IndentedTextWriter writer, ref (string? PropName, string? DeclaringType, string? PropType, SequenceEqualImmutableArray<AttributeInfo> PropAttrs, string? IndexParamList, string? IndexArgList, bool IsUnsafe) pending)
{
if (pending.PropName is null)
{
return;
}
EmitPropertyAttributes(writer, pending.PropAttrs);
EmitDeclarationHead(writer, pending.PropType!, pending.PropName!, pending.IndexParamList, pending.IsUnsafe);
writer.WriteLine('{');
writer.Indent++;
EmitAccessor(writer, isSetter: false, pending.DeclaringType!, pending.PropName!, pending.IndexArgList, pending.IsUnsafe);
writer.Indent--;
writer.WriteLine('}');
pending = default;
}
// Writes either `new T Name` (property) or `new T this[<paramList>]` (indexer) on its own line.
static void EmitDeclarationHead(IndentedTextWriter writer, string propType, string propName, string? indexParamList, bool isUnsafe)
{
string modifiers = isUnsafe ? "new unsafe" : "new";
if (indexParamList is null)
{
writer.WriteLine($"{modifiers} {propType} {propName}");
}
else
{
writer.WriteLine($"{modifiers} {propType} this[{indexParamList}]");
}
}
// Writes either `get => ((Base)this).Name;` / `set => ((Base)this).Name = value;` for properties
// or `get => ((Base)this)[<argList>];` / `set => ((Base)this)[<argList>] = value;` for indexers.
// For indexers the propName isn't part of the access expression (the IL-level naming comes
// from `[IndexerName]` propagated via AssociatedAttributes).
static void EmitAccessor(IndentedTextWriter writer, bool isSetter, string declaringType, string propName, string? indexArgList, bool isUnsafe)
{
string access = indexArgList is null
? $"(({declaringType})this).{propName}"
: $"(({declaringType})this)[{indexArgList}]";
if (!isUnsafe)
{
writer.WriteLine(isSetter
? $"set => {access} = value;"
: $"get => {access};");
return;
}
// Forwarding to a caller-unsafe member needs an unsafe context, which an expression-bodied
// accessor has nowhere to put.
writer.WriteLine(isSetter ? "set" : "get");
writer.WriteLine('{');
writer.Indent++;
writer.WriteLine("unsafe");
writer.WriteLine('{');
writer.Indent++;
writer.WriteLine(isSetter ? $"{access} = value;" : $"return {access};");
writer.Indent--;
writer.WriteLine('}');
writer.Indent--;
writer.WriteLine('}');
}
static void EmitPropertyAttributes(IndentedTextWriter writer, SequenceEqualImmutableArray<AttributeInfo> attrs)
{
// The derived-interface property shadow is a pure C# forwarder: its accessors are
// `get => ((Base)this).Prop;` / `set => ((Base)this).Prop = value;`, with no COM call
// and therefore no marshalling. Marshalling attributes declared on the source property
// are intentionally suppressed here so the shadow only carries semantically-meaningful
// user attributes (e.g. attributes used for documentation, tooling, or reflection).
//
// `[IndexerName("X")]` (for indexers) is NOT marshalling and must be propagated so the
// shadow's IL accessor names (get_X / set_X) match the source's — otherwise the runtime
// sees `get_Item` / `set_Item` and the shadow loses identity with the base indexer.
foreach (AttributeInfo attrInfo in attrs)
{
if (attrInfo.Type is "global::" + TypeNames.MarshalUsingAttribute
or "global::" + TypeNames.System_Runtime_InteropServices_MarshalAsAttribute)
{
continue;
}
writer.WriteLine($"[{attrInfo.Type}({string.Join(", ", attrInfo.Arguments)})]");
}
}
});
}
}
}