Adding GetTLSIndex cDAC implementation (#117587)

* adding GetTLSIndex cDAC implementation

Author: rcj1

src/coreclr/debug/runtimeinfo/datadescriptor.h

@@ -968,6 +968,10 @@ CDAC_GLOBAL_POINTER(StringMethodTable, &::g_pStringClass)
 CDAC_GLOBAL_POINTER(SyncTableEntries, &::g_pSyncTable)
 CDAC_GLOBAL_POINTER(MiniMetaDataBuffAddress, &::g_MiniMetaDataBuffAddress)
 CDAC_GLOBAL_POINTER(MiniMetaDataBuffMaxSize, &::g_MiniMetaDataBuffMaxSize)
+CDAC_GLOBAL_POINTER(OffsetOfCurrentThreadInfo, &::g_offsetOfCurrentThreadInfo)
+#ifdef TARGET_WINDOWS
+CDAC_GLOBAL_POINTER(TlsIndexBase, &::_tls_index)
+#endif // TARGET_WINDOWS
 #ifdef STRESS_LOG
 CDAC_GLOBAL(StressLogEnabled, uint8, 1)
 CDAC_GLOBAL_POINTER(StressLog, &g_pStressLog)

src/coreclr/inc/dacvars.h

@@ -115,6 +115,7 @@ DEFINE_DACVAR(PTR_SystemDomain, SystemDomain__m_pSystemDomain, SystemDomain::m_p
 DEFINE_DACVAR(DWORD, dac__g_debuggerWordTLSIndex, g_debuggerWordTLSIndex)
 #endif
 DEFINE_DACVAR(DWORD, dac__g_TlsIndex, g_TlsIndex)
+DEFINE_DACVAR(DWORD, dac__g_offsetOfCurrentThreadInfo, g_offsetOfCurrentThreadInfo)
 
 #ifdef FEATURE_EH_FUNCLETS
 DEFINE_DACVAR(UNKNOWN_POINTER_TYPE, dac__g_pEHClass, ::g_pEHClass)

src/coreclr/vm/threads.cpp

@@ -1142,13 +1142,13 @@ void InitThreadManager()
 #ifndef TARGET_UNIX
     _ASSERTE(GetThreadNULLOk() == NULL);
 
-    size_t offsetOfCurrentThreadInfo = Thread::GetOffsetOfThreadStatic(&t_CurrentThreadInfo);
+    g_offsetOfCurrentThreadInfo = (DWORD)Thread::GetOffsetOfThreadStatic(&t_CurrentThreadInfo);
 
-    _ASSERTE(offsetOfCurrentThreadInfo < 0x8000);
+    _ASSERTE(g_offsetOfCurrentThreadInfo < 0x8000);
     _ASSERTE(_tls_index < 0x10000);
 
     // Save t_CurrentThreadInfo location for debugger
-    SetIlsIndex((DWORD)(_tls_index + (offsetOfCurrentThreadInfo << 16) + 0x80000000));
+    SetIlsIndex((DWORD)(_tls_index + (g_offsetOfCurrentThreadInfo << 16) + 0x80000000));
 
     _ASSERTE(g_TrapReturningThreads == 0);
 #endif // !TARGET_UNIX

src/coreclr/vm/vars.cpp

@@ -93,6 +93,7 @@ GPTR_IMPL(RCWCleanupList,g_pRCWCleanupList);
 GVAL_IMPL_INIT(DWORD, g_debuggerWordTLSIndex, TLS_OUT_OF_INDEXES);
 #endif
 GVAL_IMPL_INIT(DWORD, g_TlsIndex, TLS_OUT_OF_INDEXES);
+GVAL_IMPL_INIT(DWORD, g_offsetOfCurrentThreadInfo, 0);
 
 MethodTable* g_pCastHelpers;
 #ifdef FEATURE_EH_FUNCLETS

src/coreclr/vm/vars.hpp

@@ -356,6 +356,7 @@ GPTR_DECL(MethodDesc,       g_pObjectFinalizerMD);
 GVAL_DECL(DWORD,            g_debuggerWordTLSIndex);
 #endif
 GVAL_DECL(DWORD,            g_TlsIndex);
+GVAL_DECL(DWORD,            g_offsetOfCurrentThreadInfo);
 
 #ifdef FEATURE_EH_FUNCLETS
 GPTR_DECL(MethodTable,      g_pEHClass);

src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Contracts/Constants.cs

@@ -27,6 +27,8 @@ public static class Globals
 
         public const string MiniMetaDataBuffAddress = nameof(MiniMetaDataBuffAddress);
         public const string MiniMetaDataBuffMaxSize = nameof(MiniMetaDataBuffMaxSize);
+        public const string OffsetOfCurrentThreadInfo = nameof(OffsetOfCurrentThreadInfo);
+        public const string TlsIndexBase = nameof(TlsIndexBase);
 
         public const string StressLogEnabled = nameof(StressLogEnabled);
         public const string StressLogHasModuleTable = nameof(StressLogHasModuleTable);

src/native/managed/cdac/mscordaccore_universal/Legacy/SOSDacImpl.cs

@@ -1693,8 +1693,36 @@ int ISOSDacInterface.GetThreadStoreData(DacpThreadStoreData* data)
     }
 
     int ISOSDacInterface.GetTLSIndex(uint* pIndex)
-        => _legacyImpl is not null ? _legacyImpl.GetTLSIndex(pIndex) : HResults.E_NOTIMPL;
+    {
+        if (pIndex == null)
+            return HResults.E_INVALIDARG;
 
+        int hr = HResults.S_OK;
+        try
+        {
+            uint TlsIndexBase = _target.Read<uint>(_target.ReadGlobalPointer(Constants.Globals.TlsIndexBase));
+            uint OffsetOfCurrentThreadInfo = _target.Read<uint>(_target.ReadGlobalPointer(Constants.Globals.OffsetOfCurrentThreadInfo));
+            uint CombinedTlsIndex = TlsIndexBase + (OffsetOfCurrentThreadInfo << 16) + 0x80000000;
+            *pIndex = CombinedTlsIndex;
+        }
+        catch (System.Exception ex)
+        {
+            hr = ex.HResult;
+        }
+#if DEBUG
+        if (_legacyImpl is not null)
+        {
+            uint indexLocal;
+            int hrLocal = _legacyImpl.GetTLSIndex(&indexLocal);
+            Debug.Assert(hrLocal == hr, $"cDAC: {hr:x}, DAC: {hrLocal:x}");
+            if (hr == HResults.S_OK || hr == HResults.S_FALSE)
+            {
+                Debug.Assert(*pIndex == indexLocal);
+            }
+        }
+#endif
+        return hr;
+    }
     int ISOSDacInterface.GetUsefulGlobals(DacpUsefulGlobalsData* data)
     {
         if (data == null)