Add high level unhandled exception trap

After the recent exception handling changes, we were missing a high level
exception trap in the ExecuteAssembly. While it was fine for exceptions
comming from or through managed code, it was a problem for exceptions
happening in the ExecuteAssembly call chain before the managed code was
called.
So for example when ExecuteAssembly was called for assembly that didn't
have proper file access rights for the current user, the PAL_SEHException
leaked out of the host app (corerun) and the C++ runtime displayed
message like this:
libc++abi.dylib: terminating with uncaught exception of type PAL_SEHException
Abort trap: 6
The fix is to put back the unhandled managed exception trap that I've removed
with the recent exception handling changes, but to implement it in a slightly
different way - to contain exception holder.
This way, the call to InternalUnhandledExceptionFilter_Worker can be removed
from the UnwindManagedExceptionPass1, since this new trap would ensure it
is called for both the case when the one in UnwindManagedExceptionPass1 would
kick in and the case that this issue is fixing.

1 files changed, 2 insertions, 5 deletions

diff --git a/src/vm/exceptionhandling.cpp b/src/vm/exceptionhandling.cpp
index 6a4d4d70c3..20035adbb0 100644
--- a/src/vm/exceptionhandling.cpp
+++ b/src/vm/exceptionhandling.cpp
@@ -4623,11 +4623,8 @@ VOID DECLSPEC_NORETURN UnwindManagedExceptionPass1(PAL_SEHException& ex)
 
             if (controlPc == 0)
             {
-                if (!GetThread()->HasThreadStateNC(Thread::TSNC_ProcessedUnhandledException))
-                {
-                    LONG disposition = InternalUnhandledExceptionFilter_Worker(&ex.ExceptionPointers);
-                    _ASSERTE(disposition == EXCEPTION_CONTINUE_SEARCH);
-                }
+                // The unhandled exceptions should be caught by the high level exception filter
+                _ASSERTE(!"UnwindManagedExceptionPass1: Exception escaped the stack");
                 EEPOLICY_HANDLE_FATAL_ERROR(COR_E_EXECUTIONENGINE);                    
             }