Remove obsolete NativeExceptionHolder (#121315)

This holder was used for the old EH on Unix. Now that the old EH has
been removed from the runtime quite some time ago, it is of no use
anymore.

This change removes it.

Author: janvorli

src/coreclr/dlls/mscordac/mscordac_unixexports.src

@@ -30,7 +30,6 @@ nativeStringResourceTable_mscorrc
 #PAL_GetTransportName
 #PAL_GetCurrentThread
 #PAL_GetCpuLimit
-#PAL_GetNativeExceptionHolderHead
 #PAL_GetPalHostModule
 #PAL_GetSymbolModuleBase
 #PAL_GetTransportPipeName

src/coreclr/inc/ex.h

@@ -7,9 +7,7 @@
 
 #ifdef HOST_UNIX
 #define EX_TRY_HOLDER                                   \
-    HardwareExceptionHolder                             \
-    NativeExceptionHolderCatchAll __exceptionHolder;    \
-    __exceptionHolder.Push();                           \
+    HardwareExceptionHolder
 
 #else // HOST_UNIX
 #define EX_TRY_HOLDER

src/coreclr/pal/inc/pal.h

@@ -3916,141 +3916,6 @@ class CatchHardwareExceptionHolder
 #define HardwareExceptionHolder
 #endif // FEATURE_ENABLE_HARDWARE_EXCEPTIONS
 
-class NativeExceptionHolderBase;
-
-PALIMPORT
-PALAPI
-NativeExceptionHolderBase **
-PAL_GetNativeExceptionHolderHead();
-
-extern "C++" {
-
-//
-// This is the base class of native exception holder used to provide
-// the filter function to the exception dispatcher. This allows the
-// filter to be called during the first pass to better emulate SEH
-// the xplat platforms that only have C++ exception support.
-//
-class NativeExceptionHolderBase
-{
-    // Save the address of the holder head so the destructor
-    // doesn't have access the slow (on Linux) TLS value again.
-    NativeExceptionHolderBase **m_head;
-
-    // The next holder on the stack
-    NativeExceptionHolderBase *m_next;
-
-protected:
-    NativeExceptionHolderBase()
-    {
-        m_head = nullptr;
-        m_next = nullptr;
-    }
-
-    ~NativeExceptionHolderBase()
-    {
-        // Only destroy if Push was called
-        if (m_head != nullptr)
-        {
-            *m_head = m_next;
-            m_head = nullptr;
-            m_next = nullptr;
-        }
-    }
-
-public:
-    // Calls the holder's filter handler.
-    virtual EXCEPTION_DISPOSITION InvokeFilter(PAL_SEHException& ex) = 0;
-
-    // Adds the holder to the "stack" of holders. This is done explicitly instead
-    // of in the constructor was to avoid the mess of move constructors combined
-    // with return value optimization (in CreateHolder).
-    void Push()
-    {
-        NativeExceptionHolderBase **head = PAL_GetNativeExceptionHolderHead();
-        m_head = head;
-        m_next = *head;
-        *head = this;
-    }
-
-    // Given the currentHolder and locals stack range find the next holder starting with this one
-    // To find the first holder, pass nullptr as the currentHolder.
-    static NativeExceptionHolderBase *FindNextHolder(NativeExceptionHolderBase *currentHolder, PVOID frameLowAddress, PVOID frameHighAddress);
-};
-
-//
-// This is the second part of the native exception filter holder. It is
-// templated because the lambda used to wrap the exception filter is a
-// unknown type.
-//
-template<class FilterType>
-class NativeExceptionHolder : public NativeExceptionHolderBase
-{
-    FilterType* m_exceptionFilter;
-
-public:
-    NativeExceptionHolder(FilterType* exceptionFilter)
-        : NativeExceptionHolderBase()
-    {
-        m_exceptionFilter = exceptionFilter;
-    }
-
-    virtual EXCEPTION_DISPOSITION InvokeFilter(PAL_SEHException& ex)
-    {
-        return (*m_exceptionFilter)(ex);
-    }
-};
-
-//
-// This is a native exception holder that is used when the catch catches
-// all exceptions.
-//
-class NativeExceptionHolderCatchAll : public NativeExceptionHolderBase
-{
-
-public:
-    NativeExceptionHolderCatchAll()
-        : NativeExceptionHolderBase()
-    {
-    }
-
-    virtual EXCEPTION_DISPOSITION InvokeFilter(PAL_SEHException& ex)
-    {
-        return EXCEPTION_EXECUTE_HANDLER;
-    }
-};
-
-// This is a native exception holder that doesn't catch any exceptions.
-class NativeExceptionHolderNoCatch : public NativeExceptionHolderBase
-{
-
-public:
-    NativeExceptionHolderNoCatch()
-        : NativeExceptionHolderBase()
-    {
-    }
-
-    virtual EXCEPTION_DISPOSITION InvokeFilter(PAL_SEHException& ex)
-    {
-        return EXCEPTION_CONTINUE_SEARCH;
-    }
-};
-
-//
-// This factory class for the native exception holder is necessary because
-// templated functions don't need the explicit type parameter and can infer
-// the template type from the parameter.
-//
-class NativeExceptionHolderFactory
-{
-public:
-    template<class FilterType>
-    static NativeExceptionHolder<FilterType> CreateHolder(FilterType* exceptionFilter)
-    {
-        return NativeExceptionHolder<FilterType>(exceptionFilter);
-    }
-};
-
 // Start of a try block for exceptions raised by RaiseException
 #define PAL_TRY(__ParamType, __paramDef, __paramRef)                            \
 {                                                                               \
@@ -4078,8 +3943,6 @@ class NativeExceptionHolderFactory
     try                                                                         \
     {                                                                           \
         HardwareExceptionHolder                                                 \
-        auto __exceptionHolder = NativeExceptionHolderFactory::CreateHolder(&exceptionFilter); \
-        __exceptionHolder.Push();                                               \
         tryBlock(__param);                                                      \
     }                                                                           \
     catch (PAL_SEHException& ex)                                                \
@@ -4268,10 +4131,6 @@ class NativeExceptionHolderFactory
 
 #define HRESULT_FROM_NT(x)      ((HRESULT) ((x) | FACILITY_NT_BIT))
 
-#ifdef  __cplusplus
-}
-#endif
-
 #ifndef TARGET_WASM
 #define _ReturnAddress() __builtin_return_address(0)
 #else

src/coreclr/pal/src/exception/seh.cpp

@@ -365,37 +365,4 @@ bool CatchHardwareExceptionHolder::IsEnabled()
     return pThread ? pThread->IsHardwareExceptionsEnabled() : false;
 }
 
-/*++
-
-  NativeExceptionHolderBase implementation
-
---*/
-
-static thread_local NativeExceptionHolderBase *t_nativeExceptionHolderHead = nullptr;
-
-extern "C"
-NativeExceptionHolderBase **
-PAL_GetNativeExceptionHolderHead()
-{
-    return &t_nativeExceptionHolderHead;
-}
-
-NativeExceptionHolderBase *
-NativeExceptionHolderBase::FindNextHolder(NativeExceptionHolderBase *currentHolder, PVOID stackLowAddress, PVOID stackHighAddress)
-{
-    NativeExceptionHolderBase *holder = (currentHolder == nullptr) ? t_nativeExceptionHolderHead : currentHolder->m_next;
-
-    while (holder != nullptr)
-    {
-        if (((void *)holder >= stackLowAddress) && ((void *)holder < stackHighAddress))
-        {
-            return holder;
-        }
-        // Get next holder
-        holder = holder->m_next;
-    }
-
-    return nullptr;
-}
-
 #include "seh-unwind.cpp"

src/coreclr/vm/callhelpers.h

@@ -468,20 +468,6 @@ void FillInRegTypeMap(int argOffset, CorElementType typ, BYTE * pMap);
 /* Macros used to indicate a call to managed code is starting/ending   */
 /***********************************************************************/
 
-#ifdef TARGET_UNIX
-// Install a native exception holder that doesn't catch any exceptions but its presence
-// in a stack range of native frames indicates that there was a call from native to
-// managed code. It is used by the DispatchManagedException to detect the case when
-// the INSTALL_MANAGED_EXCEPTION_DISPATCHER was not at the managed to native boundary.
-// For example in the PreStubWorker, which can be called from both native and managed
-// code.
-#define INSTALL_CALL_TO_MANAGED_EXCEPTION_HOLDER() \
-    NativeExceptionHolderNoCatch __exceptionHolder;    \
-    __exceptionHolder.Push();
-#else // TARGET_UNIX
-#define INSTALL_CALL_TO_MANAGED_EXCEPTION_HOLDER()
-#endif // TARGET_UNIX
-
 enum EEToManagedCallFlags
 {
     EEToManagedDefault                  = 0x0000,
@@ -509,7 +495,6 @@ enum EEToManagedCallFlags
             CURRENT_THREAD->HandleThreadAbort();                                \
         }                                                                       \
     }                                                                           \
-    INSTALL_CALL_TO_MANAGED_EXCEPTION_HOLDER();                                 \
     INSTALL_COMPLUS_EXCEPTION_HANDLER_NO_DECLARE();
 
 #define END_CALL_TO_MANAGED()                                                   \