[PATCH 2/7] msvcrt: Clean up registered C++ object in handler.

[Piotr Caban]

On 05/29/17 21:56, Piotr Caban wrote:
> On 05/24/17 02:55, Daniel Lehman wrote:
>> +static DWORD cxx_catch_cleanup(EXCEPTION_RECORD *rec, 
>> EXCEPTION_REGISTRATION_RECORD *frame,
>> +                               CONTEXT *context, 
>> EXCEPTION_REGISTRATION_RECORD **pdispatcher)
>> +{
>> +    if (rec->ExceptionFlags & (EH_UNWINDING | EH_EXIT_UNWIND))
>> +    {
>> +        thread_data_t *data = msvcrt_get_thread_data();
>> +        frame_info *cur;
>> +
>> +        if (cxx_is_consolidate(rec))
> Is this condition really needed? Shouldn't we clean the object no matter 
> what's the reason of unwind?
> 
>> +        {
>> +            rec = (void*)rec->ExceptionInformation[4];
>> +
>> +            for (cur = data->frame_info_head; cur; cur = cur->next)
>> +            {
>> +                if ((ULONG64)cur <= (ULONG64)frame)
> This condition is not working. It's making assumption about order of 
> catch_frame and frame_info variables on stack while they are declared 
> this way:
>> +    EXCEPTION_REGISTRATION_RECORD catch_frame;
>>       cxx_frame_info frame_info;
> Shouldn't the cxx_catch_cleanup just unregister the object that was 
> registered in call_catch_block?

Here's a test case that demonstrate the problem with cur <= frame 
comparison:

	try {
		try { int *p = NULL; *p = 0x42; }
		catch (klass x) { throw 1; }
	} catch (int i) { }

	try { throw 1; }
	catch(...) {}

Cheers,
Piotr