Removing g_hmodCoreCLR and g_hThisInst (#43735)

* g_hmodCoreCLR is Windows-only

* Use 42 in MarkAsThrownByUsWorker()

* replaced GetCLRModule with GetClrModulePathName

* Addded PAL_GetPalHostModule to mscordac_unixexports

* replaced a few cases of g_hThisInst where used to get module path. We can uise `GetClrModulePathName` instead.

* more cases where used to get module path

* unused `GetModuleInst()`

* not using HMODULE in StressLog

* removed mscoree GetModuleInst

* Deleted both  `g_hThisInst` and `g_hmodCoreCLR`

* fix Linux build

* rename `GetModuleBase` ->` GetClrModuleBase`,  it was confusing with other `GetClrModuleBase`

* Fix Linux build

* PR feedback

* Removed hMod variables in Debugger areas

* standalone GC

* cache GetClrModuleBase

* Prevent double-read of `pImageBase`

* fix linker issue

* couple more link order fixes.

* Remove `g_thisModule` in daccess.cpp. Fix typos.

Author: VSadov

src/coreclr/src/debug/daccess/daccess.cpp

@@ -40,7 +40,6 @@ extern bool TryGetSymbol(ICorDebugDataTarget* dataTarget, uint64_t baseAddress,
 
 CRITICAL_SECTION g_dacCritSec;
 ClrDataAccess* g_dacImpl;
-HINSTANCE g_thisModule;
 
 EXTERN_C
 #ifdef TARGET_UNIX
@@ -75,9 +74,6 @@ BOOL WINAPI DllMain(HANDLE instance, DWORD reason, LPVOID reserved)
 #endif
         InitializeCriticalSection(&g_dacCritSec);
 
-        // Save the module handle.
-        g_thisModule = (HINSTANCE)instance;
-
         g_procInitialized = true;
         break;
     }
@@ -95,12 +91,6 @@ BOOL WINAPI DllMain(HANDLE instance, DWORD reason, LPVOID reserved)
     return TRUE;
 }
 
-HINSTANCE
-GetModuleInst(void)
-{
-    return g_thisModule;
-}
-
 HRESULT
 ConvertUtf8(__in LPCUTF8 utf8,
             ULONG32 bufLen,
@@ -5622,16 +5612,6 @@ ClrDataAccess::Initialize(void)
     // Do some validation
     IfFailRet(VerifyDlls());
 
-    // To support EH SxS, utilcode requires the base address of the runtime
-    // as part of its initialization so that functions like "WasThrownByUs" work correctly since
-    // they use the CLR base address to check if an exception was raised by a given instance of the runtime
-    // or not.
-    //
-    // Thus, when DAC is initialized, initialize utilcode with the base address of the runtime loaded in the
-    // target process. This is similar to work done in CorDB::SetTargetCLR for mscordbi.
-
-    g_hmodCoreCLR = (HINSTANCE)m_globalBase; // Base address of the runtime in the target process
-
     return S_OK;
 }
 

src/coreclr/src/debug/daccess/dacimpl.h

@@ -127,9 +127,6 @@ enum DAC_USAGE_TYPE
     DAC_PAL,
 };
 
-// mscordacwks's module handle
-extern HINSTANCE g_thisModule;
-
 class ReflectionModule;
 
 struct DAC_MD_IMPORT

src/coreclr/src/debug/daccess/request.cpp

@@ -3889,12 +3889,22 @@ HRESULT ClrDataAccess::GetTLSIndex(ULONG *pIndex)
     return hr;
 }
 
+#ifndef TARGET_UNIX
+extern "C" IMAGE_DOS_HEADER __ImageBase;
+#endif
+
 HRESULT ClrDataAccess::GetDacModuleHandle(HMODULE *phModule)
 {
     if(phModule == NULL)
         return E_INVALIDARG;
-    *phModule = GetModuleInst();
+
+#ifndef TARGET_UNIX
+    *phModule = (HMODULE)&__ImageBase;
     return S_OK;
+#else
+    //  hModule is not available under TARGET_UNIX
+    return E_FAIL;
+#endif
 }
 
 HRESULT ClrDataAccess::GetRCWData(CLRDATA_ADDRESS addr, struct DacpRCWData *rcwData)

src/coreclr/src/debug/di/cordb.cpp

@@ -26,11 +26,6 @@
 #define SUPPORT_LOCAL_DEBUGGING 1
 #endif
 
-//********** Globals. *********************************************************
-#ifndef HOST_UNIX
-HINSTANCE       g_hInst;                // Instance handle to this piece of code.
-#endif
-
 //-----------------------------------------------------------------------------
 // SxS Versioning story for Mscordbi (ICorDebug + friends)
 //-----------------------------------------------------------------------------
@@ -200,9 +195,7 @@ BOOL WINAPI DbgDllMain(HINSTANCE hInstance, DWORD dwReason, LPVOID lpReserved)
 
         case DLL_PROCESS_ATTACH:
         {
-#ifndef HOST_UNIX
-            g_hInst = hInstance;
-#else
+#ifdef HOST_UNIX
             int err = PAL_InitializeDLL();
             if(err != 0)
             {
@@ -438,17 +431,6 @@ HRESULT STDMETHODCALLTYPE CClassFactory::LockServer(
 }
 
 
-//*****************************************************************************
-// This helper provides access to the instance handle of the loaded image.
-//*****************************************************************************
-#ifndef TARGET_UNIX
-HINSTANCE GetModuleInst()
-{
-    return g_hInst;
-}
-#endif
-
-
 //-----------------------------------------------------------------------------
 // Substitute for mscoree
 //

src/coreclr/src/debug/di/module.cpp

@@ -2565,7 +2565,7 @@ HRESULT CordbModule::CreateReaderForInMemorySymbols(REFIID riid, void** ppObj)
 #ifndef TARGET_UNIX
             // PDB format - use diasymreader.dll with COM activation
             InlineSString<_MAX_PATH> ssBuf;
-            IfFailThrow(GetHModuleDirectory(GetModuleInst(), ssBuf));
+            IfFailThrow(GetClrModuleDirectory(ssBuf));
             IfFailThrow(FakeCoCreateInstanceEx(CLSID_CorSymBinder_SxS,
                                                ssBuf.GetUnicode(),
                                                IID_ISymUnmanagedBinder,

src/coreclr/src/debug/di/rsmain.cpp

@@ -456,6 +456,7 @@ void LeftSideResourceCleanupList::SweepNeuterLeftSideResources(CordbProcess * pP
 /* ------------------------------------------------------------------------- *
  * CordbBase class
  * ------------------------------------------------------------------------- */
+extern void* GetClrModuleBase();
 
 // Do any initialization necessary for both CorPublish and CorDebug
 // This includes enabling logging and adding the SEDebug priv.
@@ -488,11 +489,7 @@ void CordbCommonBase::InitializeCommon()
             unsigned level = REGUTIL::GetConfigDWORD_DontUse_(CLRConfig::EXTERNAL_LogLevel, LL_INFO1000);
             unsigned bytesPerThread = REGUTIL::GetConfigDWORD_DontUse_(CLRConfig::UNSUPPORTED_StressLogSize, STRESSLOG_CHUNK_SIZE * 2);
             unsigned totalBytes = REGUTIL::GetConfigDWORD_DontUse_(CLRConfig::UNSUPPORTED_TotalStressLogSize, STRESSLOG_CHUNK_SIZE * 1024);
-#ifndef TARGET_UNIX
-            StressLog::Initialize(facilities, level, bytesPerThread, totalBytes, GetModuleInst());
-#else
-            StressLog::Initialize(facilities, level, bytesPerThread, totalBytes, NULL);
-#endif
+            StressLog::Initialize(facilities, level, bytesPerThread, totalBytes, GetClrModuleBase());
         }
     }
 
@@ -1427,13 +1424,6 @@ HRESULT Cordb::SetTargetCLR(HMODULE hmodTargetCLR)
     m_targetCLR = hmodTargetCLR;
 #endif
 
-    // @REVIEW: are we happy with this workaround?  It allows us to use the existing
-    // infrastructure for instance name decoration, but it really doesn't fit
-    // the same model because coreclr.dll isn't in this process and hmodTargetCLR
-    // is the debuggee target, not the coreclr.dll to bind utilcode to..
-
-    g_hmodCoreCLR = hmodTargetCLR;
-
     return S_OK;
 }
 

src/coreclr/src/debug/di/rspriv.h

@@ -134,12 +134,6 @@ class DbgTransportSession;
 // These hooks must be removed before shipping.
 class ShimProcess;
 
-
-#ifndef TARGET_UNIX
-extern HINSTANCE GetModuleInst();
-#endif
-
-
 template <class T>
 class CordbSafeHashTable;
 

src/coreclr/src/debug/di/shimprocess.cpp

@@ -1824,34 +1824,19 @@ HMODULE ShimProcess::GetDacModule()
     HModuleHolder hDacDll;
     PathString wszAccessDllPath;
 
-#ifdef TARGET_UNIX
-    if (!PAL_GetPALDirectoryWrapper(wszAccessDllPath))
-    {
-        ThrowLastError();
-    }
-    PCWSTR eeFlavor = MAKEDLLNAME_W(W("mscordaccore"));
-#else
     //
     // Load the access DLL from the same directory as the the current CLR Debugging Services DLL.
     //
-
-    if (!WszGetModuleFileName(GetModuleInst(), wszAccessDllPath))
+    if (GetClrModuleDirectory(wszAccessDllPath) != S_OK)
     {
         ThrowLastError();
     }
 
-	if (!SUCCEEDED(CopySystemDirectory(wszAccessDllPath, wszAccessDllPath)))
-    {
-        ThrowHR(E_INVALIDARG);
-    }
-
     // Dac Dll is named:
     //   mscordaccore.dll  <-- coreclr
     //   mscordacwks.dll   <-- desktop
-    PCWSTR eeFlavor =
-        W("mscordaccore.dll");
+    PCWSTR eeFlavor = MAKEDLLNAME_W(W("mscordaccore"));
 
-#endif // TARGET_UNIX
     wszAccessDllPath.Append(eeFlavor);
 
     hDacDll.Assign(WszLoadLibrary(wszAccessDllPath));

src/coreclr/src/debug/ee/debugger.cpp

@@ -1750,7 +1750,7 @@ void Debugger::SendRawEvent(const DebuggerIPCEvent * pManagedEvent)
     // The debugger can then use ReadProcessMemory to read through this array.
     ULONG_PTR rgData [] = {
         CLRDBG_EXCEPTION_DATA_CHECKSUM,
-        (ULONG_PTR) g_hThisInst,
+        (ULONG_PTR)GetClrModuleBase(),
         (ULONG_PTR) pManagedEvent
     };
 
@@ -5668,7 +5668,7 @@ bool Debugger::FirstChanceNativeException(EXCEPTION_RECORD *exception,
     // Ignore any notification exceptions sent from code:Debugger.SendRawEvent.
     // This is not a common case, but could happen in some cases described
     // in SendRawEvent. Either way, Left-Side and VM should just ignore these.
-    if (IsEventDebuggerNotification(exception, PTR_TO_CORDB_ADDRESS(g_hThisInst)))
+    if (IsEventDebuggerNotification(exception, PTR_TO_CORDB_ADDRESS(GetClrModuleBase())))
     {
         return true;
     }
@@ -12363,7 +12363,7 @@ void Debugger::GetAndSendTransitionStubInfo(CORDB_ADDRESS_TYPE *stubAddress)
     // If its not a stub, then maybe its an address in mscoree?
     if (result == false)
     {
-        result = (IsIPInModule(g_hThisInst, (PCODE)stubAddress) == TRUE);
+        result = (IsIPInModule(GetClrModuleBase(), (PCODE)stubAddress) == TRUE);
     }
 
     // This is a synchronous event (reply required)

src/coreclr/src/dlls/mscordac/mscordac_unixexports.src

@@ -30,14 +30,14 @@ nativeStringResourceTable_mscorrc
 #PAL_fwprintf
 #PAL_GetLogicalCpuCountFromOS
 #PAL_GetNumaProcessorNode
-#PAL_GetPALDirectoryW
 #PAL_get_stdout
 #PAL_get_stderr
 #PAL_GetApplicationGroupId
 #PAL_GetTransportName
 #PAL_GetCurrentThread
 #PAL_GetCpuLimit
 #PAL_GetNativeExceptionHolderHead
+#PAL_GetPalHostModule
 #PAL_GetSymbolModuleBase
 #PAL_GetTransportPipeName
 #PAL_InitializeDLL