[LLVMdev] Assertion failure in llc when using exception handling

[Kenneth Uildriks]

On Thu, Jun 10, 2010 at 3:28 AM, Duncan Sands <baldrick at free.fr> wrote:
> Hi Shivram,
>
>> I'm trying to compile an llvm program which makes use of exception
>> handling. While compiling the code with llc i get the following
>> assertion failure
>
> an unfortunate weakness of the code generators is that they require calls to
> eh.selector to be in a landing pad (landing pad = where an invoke unwinds
> to).  They can also handle some simple cases when the selector call is outside
> the landing pad.  In practice, as long as the original call to eh.selector that
> you generate is in a landing pad, and at the start of the landing pad (just
> after the eh.exception call and any phi nodes) it is intended that the current
> logic is good enough to handle any situations caused by optimization.  Was the
> original call at the start of a landing pad?
>
> By the way, there are various ways of fixing this codegen problem.  But since
> there is a plan to redesign exception handling in LLVM, it seems pointless to
> spend much time on it.

Is the plan still as specified in
http://www.nondot.org/sabre/LLVMNotes/ExceptionHandlingChanges.txt?
Is there a particular person or persons considered highly likely to
work on it at a roughly known time?

(I wish I had the time and knowledge to knock it out myself...)

I have been putting off implementing exception handling in my front
end, and would like to know whether to continue putting it off.

Also, a more general question: is exception handling (in the
hardware/OS) more or less universally supported across LLVM target
platforms?