Adding GetAppDomainName cDAC API (#117837)

rcj1 · Copilot · web-flow · commit 2d3bf386a579 · 2025-07-28T18:39:00.000-07:00
* Adding GetAppDomainName cDAC API 

Co-authored-by: Copilot &lt;175728472+Copilot@users.noreply.github.com&gt;
diff --git a/docs/design/datacontracts/Loader.md b/docs/design/datacontracts/Loader.md
@@ -56,6 +56,7 @@ ModuleHandle GetModuleHandleFromModulePtr(TargetPointer module);
 ModuleHandle GetModuleHandleFromAssemblyPtr(TargetPointer assemblyPointer);
 IEnumerable<ModuleHandle> GetModuleHandles(TargetPointer appDomain, AssemblyIterationFlags iterationFlags);
 TargetPointer GetRootAssembly();
+string GetAppDomainFriendlyName();
 TargetPointer GetModule(ModuleHandle handle);
 TargetPointer GetAssembly(ModuleHandle handle);
 TargetPointer GetPEAssembly(ModuleHandle handle);
@@ -116,6 +117,7 @@ TargetPointer GetStubHeap(TargetPointer loaderAllocatorPointer);
 | `CGrowableSymbolStream` | `Size` | Size of the raw symbol stream buffer |
 | `AppDomain` | `RootAssembly` | Pointer to the root assembly |
 | `AppDomain` | `DomainAssemblyList` | ArrayListBase of assemblies in the AppDomain |
+| `AppDomain` | `FriendlyName` | Friendly name of the AppDomain |
 | `LoaderAllocator` | `ReferenceCount` | Reference count of LoaderAllocator |
 | `LoaderAllocator` | `HighFrequencyHeap` | High-frequency heap of LoaderAllocator |
 | `LoaderAllocator` | `LowFrequencyHeap` | Low-frequency heap of LoaderAllocator |
@@ -270,6 +272,15 @@ TargetPointer GetRootAssembly()
     return appDomain.RootAssembly;
 }
 
+string ILoader.GetAppDomainFriendlyName()
+{
+    TargetPointer appDomainPointer = target.ReadGlobalPointer(Constants.Globals.AppDomain);
+    TargetPointer appDomain = target.ReadPointer(appDomainPointer)
+    TargetPointer pathStart = appDomain + /* AppDomain::FriendlyName offset */;
+    char[] name = // Read<char> from target starting at pathStart until null terminator
+    return new string(name);
+}
+
 TargetPointer ILoader.GetModule(ModuleHandle handle)
 {
     return handle.Address;
@@ -395,20 +406,20 @@ TargetPointer GetModuleLookupMapElement(TargetPointer table, uint token, out Tar
     uint index = rid;
     // have to read lookupMap an extra time upfront because only the first map
     // has valid supportedFlagsMask
-    TargetNUInt supportedFlagsMask = _target.ReadNUInt(table + /* ModuleLookupMap::SupportedFlagsMask */);
+    TargetNUInt supportedFlagsMask = target.ReadNUInt(table + /* ModuleLookupMap::SupportedFlagsMask */);
     do
     {
-        if (index < _target.Read<uint>(table + /*ModuleLookupMap::Count*/))
+        if (index < target.Read<uint>(table + /*ModuleLookupMap::Count*/))
         {
-            TargetPointer entryAddress = _target.ReadPointer(lookupMap + /*ModuleLookupMap::TableData*/) + (ulong)(index * _target.PointerSize);
-            TargetPointer rawValue = _target.ReadPointer(entryAddress);
+            TargetPointer entryAddress = target.ReadPointer(lookupMap + /*ModuleLookupMap::TableData*/) + (ulong)(index * target.PointerSize);
+            TargetPointer rawValue = target.ReadPointer(entryAddress);
             flags = rawValue & supportedFlagsMask;
             return rawValue & ~(supportedFlagsMask.Value);
         }
         else
         {
-            table = _target.ReadPointer(lookupMap + /*ModuleLookupMap::Next*/);
-            index -= _target.Read<uint>(lookupMap + /*ModuleLookupMap::Count*/);
+            table = target.ReadPointer(lookupMap + /*ModuleLookupMap::Next*/);
+            index -= target.Read<uint>(lookupMap + /*ModuleLookupMap::Count*/);
         }
     } while (table != TargetPointer.Null);
     return TargetPointer.Null;
diff --git a/src/coreclr/debug/runtimeinfo/datadescriptor.inc b/src/coreclr/debug/runtimeinfo/datadescriptor.inc
@@ -295,6 +295,7 @@ CDAC_TYPE_BEGIN(AppDomain)
 CDAC_TYPE_INDETERMINATE(AppDomain)
 CDAC_TYPE_FIELD(AppDomain, /*pointer*/, RootAssembly, cdac_data<AppDomain>::RootAssembly)
 CDAC_TYPE_FIELD(AppDomain, /*DomainAssemblyList*/, DomainAssemblyList, cdac_data<AppDomain>::DomainAssemblyList)
+CDAC_TYPE_FIELD(AppDomain, /*pointer*/, FriendlyName, cdac_data<AppDomain>::FriendlyName)
 CDAC_TYPE_END(AppDomain)
 
 CDAC_TYPE_BEGIN(SystemDomain)
diff --git a/src/coreclr/vm/appdomain.hpp b/src/coreclr/vm/appdomain.hpp
@@ -1571,6 +1571,7 @@ struct cdac_data<AppDomain>
 {
     static constexpr size_t RootAssembly = offsetof(AppDomain, m_pRootAssembly);
     static constexpr size_t DomainAssemblyList = offsetof(AppDomain, m_Assemblies) + offsetof(AppDomain::DomainAssemblyList, m_array);
+    static constexpr size_t FriendlyName = offsetof(AppDomain, m_friendlyName);
 };
 
 typedef DPTR(class SystemDomain) PTR_SystemDomain;
diff --git a/src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Abstractions/Contracts/ILoader.cs b/src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Abstractions/Contracts/ILoader.cs
@@ -79,6 +79,7 @@ public interface ILoader : IContract
     ModuleHandle GetModuleHandleFromAssemblyPtr(TargetPointer assemblyPointer) => throw new NotImplementedException();
     IEnumerable<ModuleHandle> GetModuleHandles(TargetPointer appDomain, AssemblyIterationFlags iterationFlags) => throw new NotImplementedException();
     TargetPointer GetRootAssembly() => throw new NotImplementedException();
+    string GetAppDomainFriendlyName() => throw new NotImplementedException();
     TargetPointer GetModule(ModuleHandle handle) => throw new NotImplementedException();
     TargetPointer GetAssembly(ModuleHandle handle) => throw new NotImplementedException();
     TargetPointer GetPEAssembly(ModuleHandle handle) => throw new NotImplementedException();
diff --git a/src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Contracts/Loader_1.cs b/src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Contracts/Loader_1.cs
@@ -139,6 +139,16 @@ TargetPointer ILoader.GetRootAssembly()
         Data.AppDomain appDomain = _target.ProcessedData.GetOrAdd<Data.AppDomain>(_target.ReadPointer(appDomainPointer));
         return appDomain.RootAssembly;
     }
+
+    string ILoader.GetAppDomainFriendlyName()
+    {
+        TargetPointer appDomainPointer = _target.ReadGlobalPointer(Constants.Globals.AppDomain);
+        Data.AppDomain appDomain = _target.ProcessedData.GetOrAdd<Data.AppDomain>(_target.ReadPointer(appDomainPointer));
+        return appDomain.FriendlyName != TargetPointer.Null
+            ? _target.ReadUtf16String(appDomain.FriendlyName)
+            : string.Empty;
+    }
+
     TargetPointer ILoader.GetModule(ModuleHandle handle)
     {
         return handle.Address;
diff --git a/src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Data/AppDomain.cs b/src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Data/AppDomain.cs
@@ -14,8 +14,10 @@ public AppDomain(Target target, TargetPointer address)
 
         RootAssembly = target.ReadPointer(address + (ulong)type.Fields[nameof(RootAssembly)].Offset);
         DomainAssemblyList = address + (ulong)type.Fields[nameof(DomainAssemblyList)].Offset;
+        FriendlyName = target.ReadPointer(address + (ulong)type.Fields[nameof(FriendlyName)].Offset);
     }
 
     public TargetPointer RootAssembly { get; init; }
     public TargetPointer DomainAssemblyList { get; init; }
+    public TargetPointer FriendlyName { get; init; }
 }
diff --git a/src/native/managed/cdac/mscordaccore_universal/Legacy/SOSDacImpl.cs b/src/native/managed/cdac/mscordaccore_universal/Legacy/SOSDacImpl.cs
@@ -227,7 +227,62 @@ int ISOSDacInterface.GetAppDomainList(uint count, [In, MarshalUsing(CountElement
         return hr;
     }
     int ISOSDacInterface.GetAppDomainName(ClrDataAddress addr, uint count, char* name, uint* pNeeded)
-        => _legacyImpl is not null ? _legacyImpl.GetAppDomainName(addr, count, name, pNeeded) : HResults.E_NOTIMPL;
+    {
+        int hr = HResults.S_OK;
+        try
+        {
+            ILoader loader = _target.Contracts.Loader;
+            string friendlyName = loader.GetAppDomainFriendlyName();
+            TargetPointer systemDomainPtr = _target.ReadGlobalPointer(Constants.Globals.SystemDomain);
+            ClrDataAddress systemDomain = _target.ReadPointer(systemDomainPtr).ToClrDataAddress(_target);
+            if (addr == systemDomain || friendlyName == string.Empty)
+            {
+                if (pNeeded is not null)
+                {
+                    *pNeeded = 1;
+                }
+                if (name is not null && count > 0)
+                {
+                    name[0] = '\0'; // Set the first character to null terminator
+                }
+            }
+            else
+            {
+                if (pNeeded is not null)
+                {
+                    *pNeeded = (uint)(friendlyName.Length + 1); // +1 for null terminator
+                }
+
+                if (name is not null && count > 0)
+                {
+                    OutputBufferHelpers.CopyStringToBuffer(name, count, pNeeded, friendlyName);
+                }
+            }
+        }
+        catch (System.Exception ex)
+        {
+            hr = ex.HResult;
+        }
+#if DEBUG
+        if (_legacyImpl is not null)
+        {
+            uint neededLocal;
+            char[] nameLocal = new char[count];
+            int hrLocal;
+            fixed (char* ptr = nameLocal)
+            {
+                hrLocal = _legacyImpl.GetAppDomainName(addr, count, ptr, &neededLocal);
+            }
+            Debug.Assert(hrLocal == hr, $"cDAC: {hr:x}, DAC: {hrLocal:x}");
+            if (hr == HResults.S_OK)
+            {
+                Debug.Assert(pNeeded == null || *pNeeded == neededLocal);
+                Debug.Assert(name == null || new ReadOnlySpan<char>(nameLocal, 0, (int)neededLocal - 1).SequenceEqual(new string(name)));
+            }
+        }
+#endif
+        return hr;
+    }
     int ISOSDacInterface.GetAppDomainStoreData(void* data)
     {
         DacpAppDomainStoreData* appDomainStoreData = (DacpAppDomainStoreData*)data;

Original file line number	Diff line number	Diff line change
`@@ -1571,6 +1571,7 @@ struct cdac_data<AppDomain>`
`1571`	`1571`	`{`
`1572`	`1572`	`static constexpr size_t RootAssembly = offsetof(AppDomain, m_pRootAssembly);`
`1573`	`1573`	`static constexpr size_t DomainAssemblyList = offsetof(AppDomain, m_Assemblies) + offsetof(AppDomain::DomainAssemblyList, m_array);`
	`1574`	`+ static constexpr size_t FriendlyName = offsetof(AppDomain, m_friendlyName);`
`1574`	`1575`	`};`
`1575`	`1576`
`1576`	`1577`	`typedef DPTR(class SystemDomain) PTR_SystemDomain;`
Original file line number	Diff line number	Diff line change
`@@ -14,8 +14,10 @@ public AppDomain(Target target, TargetPointer address)`
`14`	`14`
`15`	`15`	`RootAssembly = target.ReadPointer(address + (ulong)type.Fields[nameof(RootAssembly)].Offset);`
`16`	`16`	`DomainAssemblyList = address + (ulong)type.Fields[nameof(DomainAssemblyList)].Offset;`
	`17`	`+ FriendlyName = target.ReadPointer(address + (ulong)type.Fields[nameof(FriendlyName)].Offset);`
`17`	`18`	`}`
`18`	`19`
`19`	`20`	`public TargetPointer RootAssembly { get; init; }`
`20`	`21`	`public TargetPointer DomainAssemblyList { get; init; }`
	`22`	`+ public TargetPointer FriendlyName { get; init; }`
`21`	`23`	`}`