[LLVMdev] Exception handling question

[James Williams]

2010/1/22 Garrison Venn <gvenn.cfe.dev at gmail.com>

> Hi James,
>
> Looking at:
>
> %7 = invoke i8* (...)* bitcast (i32 (%struct._Unwind_Exception*)*
> @_Unwind_RaiseException to i8* (...)*)(i64* %6)
>           to label %8 unwind label %.finally_pad  ; <i8*> [#uses=0]
>
> I am not sure this is going to work, at least from the way I've played with
> the system.
> In my examples the _Unwind_RaiseException(...) is called from a frame
> (function) called via
> the invoke instruction, not from a frame that contains the invoke
> instruction.
>
> Garrison
>

Hi,

Thanks but I've also tried calling both a separate C function that then
calls _Unwind_RaiseException and also a C++ function that throws an integer
with the same results. I've also just tried running the example code posted
earlier by Duncan and I find that doesn't reach the landing pad either if
g() is replaced with a C++ function containing "throw 1".

I'm building LLVM from svn head now and I'll retry Dunan's example against
that.

-- James

BTW: I found the exception handling docs on the wiki very helpful

>
> On Jan 22, 2010, at 6:09, James Williams wrote:
>
>
>
> 2010/1/22 James Williams <junk at giantblob.com>
>
>>
>>
>> 2010/1/22 Duncan Sands <baldrick at free.fr>
>>
>>> Hi James,
>>>
>>>
>>>  I get the expected output (after changing i32 @llvm.eh.selector() to i64
>>>> llvm.eh.selector.i64())
>>>>
>>>
>>> in top-of-tree, llvm.eh.selector.i64 has been removed (though bitcode
>>> will
>>> autoupgrade) and there is only i32 @llvm.eh.selector(), which is why my
>>> example
>>> was written this way.
>>>
>> OK. I understand.
>>
>> Thanks again for the help.
>> -- James
>>
> Sorry. I think I was being very stupid. It looks like I was reading the
> tables wrong and the eh tables are probably actually correct for all my
> tests. I didn't realise the personality function went in a separate shared
> entry. I'm still not sure why it's not getting called by
> _Unwind_RaiseException but I don't think it's due to any problem with LLVM
> eh table output
>
> -- James
>
>
>>
>>> Ciao,
>>>
>>> Duncan.
>>>
>>>
>>
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