[cDAC] Implement GetCurrentAppDomain on IXCLRDataTask

src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Legacy/ClrDataAppDomain.cs

@@ -0,0 +1,70 @@
+// 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.Diagnostics;
+using System.Runtime.InteropServices;
+using System.Runtime.InteropServices.Marshalling;
+
+namespace Microsoft.Diagnostics.DataContractReader.Legacy;
+
+[GeneratedComClass]
+public sealed unsafe partial class ClrDataAppDomain : IXCLRDataAppDomain
+{
+    private readonly TargetPointer _appDomain;
+    private readonly IXCLRDataAppDomain? _legacyImpl;
+
+    public TargetPointer Address => _appDomain;
+
+    public ClrDataAppDomain(TargetPointer appDomain, IXCLRDataAppDomain? legacyImpl)
+    {
+        _appDomain = appDomain;
+        _legacyImpl = legacyImpl;
+    }
+
+    int IXCLRDataAppDomain.GetProcess(/*IXCLRDataProcess*/ void** process)
+        => _legacyImpl is not null ? _legacyImpl.GetProcess(process) : HResults.E_NOTIMPL;
+
+    int IXCLRDataAppDomain.GetName(uint bufLen, uint* nameLen, char* name)
+        => _legacyImpl is not null ? _legacyImpl.GetName(bufLen, nameLen, name) : HResults.E_NOTIMPL;
+
+    int IXCLRDataAppDomain.GetUniqueID(ulong* id)
+        => _legacyImpl is not null ? _legacyImpl.GetUniqueID(id) : HResults.E_NOTIMPL;
+
+    int IXCLRDataAppDomain.GetFlags(uint* flags)
+        => _legacyImpl is not null ? _legacyImpl.GetFlags(flags) : HResults.E_NOTIMPL;
+
+    int IXCLRDataAppDomain.IsSameObject(IXCLRDataAppDomain* appDomain)
+    {
+        int hr = HResults.S_FALSE;
+        try
+        {
+            StrategyBasedComWrappers cw = new();
+            object obj = cw.GetOrCreateObjectForComInstance((nint)appDomain, CreateObjectFlags.None);
+            if (obj is ClrDataAppDomain other)
+            {
+                hr = _appDomain == other._appDomain ? HResults.S_OK : HResults.S_FALSE;
+            }
+        }
+        catch (Exception ex)
+        {
+            hr = ex.HResult;
+        }
+
+#if DEBUG
+        if (_legacyImpl is not null)
+        {
+            int hrLocal = _legacyImpl.IsSameObject(appDomain);
+            Debug.Assert(hrLocal == hr, $"cDAC: {hr}, DAC: {hrLocal}");
+        }
+#endif
+
+        return hr;
+    }
+
+    int IXCLRDataAppDomain.GetManagedObject(/*IXCLRDataValue*/ void** value)
+        => _legacyImpl is not null ? _legacyImpl.GetManagedObject(value) : HResults.E_NOTIMPL;
+
+    int IXCLRDataAppDomain.Request(uint reqCode, uint inBufferSize, byte* inBuffer, uint outBufferSize, byte* outBuffer)
+        => _legacyImpl is not null ? _legacyImpl.Request(reqCode, inBufferSize, inBuffer, outBufferSize, outBuffer) : HResults.E_NOTIMPL;
+}

src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Legacy/ClrDataFrame.cs

@@ -40,7 +40,7 @@ int IXCLRDataFrame.GetContext(
         [Out, MarshalUsing(CountElementName = nameof(contextBufSize))] byte[] contextBuf)
         => _legacyImpl is not null ? _legacyImpl.GetContext(contextFlags, contextBufSize, contextSize, contextBuf) : HResults.E_NOTIMPL;
 
-    int IXCLRDataFrame.GetAppDomain(void** appDomain)
+    int IXCLRDataFrame.GetAppDomain(/*IXCLRDataAppDomain*/ void** appDomain)
         => _legacyImpl is not null ? _legacyImpl.GetAppDomain(appDomain) : HResults.E_NOTIMPL;
 
     int IXCLRDataFrame.GetNumArguments(uint* numArgs)

src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Legacy/ClrDataTask.cs

@@ -23,8 +23,33 @@ public ClrDataTask(TargetPointer address, Target target, IXCLRDataTask? legacyIm
 
     int IXCLRDataTask.GetProcess(/*IXCLRDataProcess*/ void** process)
         => _legacyImpl is not null ? _legacyImpl.GetProcess(process) : HResults.E_NOTIMPL;
-    int IXCLRDataTask.GetCurrentAppDomain(/*IXCLRDataAppDomain*/ void** appDomain)
-        => _legacyImpl is not null ? _legacyImpl.GetCurrentAppDomain(appDomain) : HResults.E_NOTIMPL;
+    int IXCLRDataTask.GetCurrentAppDomain(out IXCLRDataAppDomain? appDomain)
+    {
+        int hr = HResults.S_OK, hrLocal = HResults.S_OK;
+        appDomain = null;
+        IXCLRDataAppDomain? legacyAppDomain = null;
+
+        if (_legacyImpl is not null)
+        {
+            hrLocal = _legacyImpl.GetCurrentAppDomain(out legacyAppDomain);
+        }
+        try
+        {
+            TargetPointer currentAppDomain = _target.ReadPointer(_target.ReadGlobalPointer(Constants.Globals.AppDomain));
+            appDomain = new ClrDataAppDomain(currentAppDomain, legacyAppDomain);
+        }
+        catch (System.Exception ex)
+        {
+            hr = ex.HResult;
+        }
+#if DEBUG
+        if (_legacyImpl is not null)
+        {
+            System.Diagnostics.Debug.Assert(hrLocal == hr, $"cDAC: {hr:x}, DAC: {hrLocal:x}");
+        }
+#endif
+        return hr;
+    }
     int IXCLRDataTask.GetUniqueID(ulong* id)
         => _legacyImpl is not null ? _legacyImpl.GetUniqueID(id) : HResults.E_NOTIMPL;
     int IXCLRDataTask.GetFlags(uint* flags)

src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Legacy/IXCLRData.cs

@@ -447,7 +447,7 @@ public unsafe partial interface IXCLRDataTask
     int GetProcess(/*IXCLRDataProcess*/ void** process);
 
     [PreserveSig]
-    int GetCurrentAppDomain(/*IXCLRDataAppDomain*/ void** appDomain);
+    int GetCurrentAppDomain(out IXCLRDataAppDomain? appDomain);
 
     [PreserveSig]
     int GetUniqueID(ulong* id);
@@ -595,7 +595,7 @@ public unsafe partial interface IXCLRDataAppDomain
     [PreserveSig]
     int GetFlags(uint* flags);
     [PreserveSig]
-    int IsSameObject(/*IXCLRDataAppDomain*/ void* appDomain);
+    int IsSameObject(IXCLRDataAppDomain* appDomain);
     [PreserveSig]
     int GetManagedObject(/*IXCLRDataValue*/ void** value);
     [PreserveSig]

src/native/managed/cdac/tests/ClrDataTaskTests.cs

@@ -0,0 +1,45 @@
+// 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 Microsoft.Diagnostics.DataContractReader.Legacy;
+using Xunit;
+
+namespace Microsoft.Diagnostics.DataContractReader.Tests;
+
+public unsafe class ClrDataTaskTests
+{
+    [Theory]
+    [ClassData(typeof(MockTarget.StdArch))]
+    public void GetCurrentAppDomain(MockTarget.Architecture arch)
+    {
+        TargetTestHelpers helpers = new(arch);
+        MockMemorySpace.Builder builder = new(helpers);
+
+        ulong globalPtrAddr = 0x1000;
+        ulong expectedAppDomain = 0x2000;
+
+        byte[] ptrData = new byte[helpers.PointerSize];
+        helpers.WritePointer(ptrData, expectedAppDomain);
+        builder.AddHeapFragment(new MockMemorySpace.HeapFragment
+        {
+            Address = globalPtrAddr,
+            Data = ptrData,
+            Name = "AppDomainGlobalPointer"
+        });
+
+        var target = new TestPlaceholderTarget(
+            arch,
+            builder.GetMemoryContext().ReadFromTarget,
+            globals: [(Constants.Globals.AppDomain, globalPtrAddr)]);
+
+        TargetPointer taskAddress = new TargetPointer(0x5000);
+        IXCLRDataTask task = new ClrDataTask(taskAddress, target, legacyImpl: null);
+        int hr = task.GetCurrentAppDomain(out IXCLRDataAppDomain? appDomain);
+
+        Assert.Equal(HResults.S_OK, hr);
+        Assert.NotNull(appDomain);
+        ClrDataAppDomain clrAppDomain = Assert.IsType<ClrDataAppDomain>(appDomain);
+        Assert.Equal(new TargetPointer(expectedAppDomain), clrAppDomain.Address);
+    }
+}