[Release/8.0] Remove preventing EH at shutdown (#100836)

Partial backport of #100293 to release/8.0

src/coreclr/vm/ceemain.cpp

@@ -1331,9 +1331,6 @@ void STDMETHODCALLTYPE EEShutDownHelper(BOOL fIsDllUnloading)
                 // Shutdown finalizer before we suspend all background threads. Otherwise we
                 // never get to finalize anything.
 
-                // No longer process exceptions
-                g_fNoExceptions = true;
-
                 // <TODO>@TODO: This does things which shouldn't occur in part 2.  Namely,
                 // calling managed dll main callbacks (AppDomain::SignalProcessDetach), and
                 // RemoveAppDomainFromIPC.

src/coreclr/vm/eepolicy.cpp

@@ -59,13 +59,6 @@ void SafeExitProcess(UINT exitCode, ShutdownCompleteAction sca = SCA_ExitProcess
         }
     }
 
-    // Turn off exception processing, because if some other random DLL has a
-    //  fault in DLL_PROCESS_DETACH, we could get called for exception handling.
-    //  Since we've turned off part of the runtime, we can't, for instance,
-    //  properly execute the GC that handling an exception might trigger.
-    g_fNoExceptions = true;
-    LOG((LF_EH, LL_INFO10, "SafeExitProcess: turning off exceptions\n"));
-
     if (sca == SCA_TerminateProcessWhenShutdownComplete)
     {
         // disabled because if we fault in this code path we will trigger our Watson code

src/coreclr/vm/excep.cpp

@@ -4623,12 +4623,6 @@ LONG InternalUnhandledExceptionFilter_Worker(
     }
 #endif
 
-    // This shouldn't be possible, but MSVC re-installs us... for now, just bail if this happens.
-    if (g_fNoExceptions)
-    {
-        return EXCEPTION_CONTINUE_SEARCH;
-    }
-
     // Are we looking at a stack overflow here?
     if ((pThread !=  NULL) && !pThread->DetermineIfGuardPagePresent())
     {
@@ -5533,8 +5527,6 @@ static LONG ThreadBaseExceptionFilter_Worker(PEXCEPTION_POINTERS pExceptionInfo,
     ThreadBaseExceptionFilterParam *pParam = (ThreadBaseExceptionFilterParam *) pvParam;
     UnhandledExceptionLocation location = pParam->location;
 
-    _ASSERTE(!g_fNoExceptions);
-
     Thread* pThread = GetThread();
 
 #ifdef _DEBUG
@@ -7393,8 +7385,8 @@ LONG WINAPI CLRVectoredExceptionHandlerShim(PEXCEPTION_POINTERS pExceptionInfo)
     // WARNING WARNING WARNING WARNING WARNING WARNING WARNING
     //
 
-    // If exceptions (or runtime) have been disabled, then simply return.
-    if (g_fForbidEnterEE || g_fNoExceptions)
+    // If runtime have been disabled, then simply return.
+    if (g_fForbidEnterEE)
     {
         return EXCEPTION_CONTINUE_SEARCH;
     }

src/coreclr/vm/i386/excepx86.cpp

@@ -1571,9 +1571,6 @@ EXCEPTION_HANDLER_IMPL(COMPlusFrameHandler)
 
     _ASSERTE((pContext == NULL) || ((pContext->ContextFlags & CONTEXT_CONTROL) == CONTEXT_CONTROL));
 
-    if (g_fNoExceptions)
-        return ExceptionContinueSearch; // No EH during EE shutdown.
-
     // Check if the exception represents a GCStress Marker. If it does,
     // we shouldnt record its entry in the TLS as such exceptions are
     // continuable and can confuse the VM to treat them as CSE,

src/coreclr/vm/vars.cpp

@@ -193,7 +193,6 @@ GVAL_IMPL(SIZE_T, g_runtimeVirtualSize);
 
 Volatile<LONG> g_fForbidEnterEE = false;
 bool g_fManagedAttach = false;
-bool g_fNoExceptions = false;
 
 DWORD g_FinalizerWaiterStatus = 0;
 

src/coreclr/vm/vars.hpp

@@ -477,7 +477,6 @@ GVAL_DECL(bool, g_fProcessDetach);
 GVAL_DECL(bool, g_metadataUpdatesApplied);
 #endif
 EXTERN bool g_fManagedAttach;
-EXTERN bool g_fNoExceptions;
 
 // Indicates whether we're executing shut down as a result of DllMain
 // (DLL_PROCESS_DETACH). See comments at code:EEShutDown for details.