llvm dev - Jul 2010 - [LLVMdev] Why clang++ doesn't set 'noreturn' flag on declarations of __cxa_throw and _Unwind_Resume_or_Rethrow ?

On Jul 15, 2010, at 5:51 PM, John McCall wrote:
>> Also can _Unwind_Resume_or_Rethrow actually return? When I run some 
>> simple exception code in JIT I see that this function actually returns 
>> and then SEGVs.
> 
> I have no idea what system you're on, but _Unwind_Resume_or_Rethrow
really
> isn't allowed to return.
> 
It's not. But if the unwind library can't handle something, then the
_Unwind_Resume_or_Rethrow could fall out of the function (it would assert in
debug mode). Darwin's implementation of _URoR in libunwind does this.

-bw

On 07/15/2010 18:30, Bill Wendling wrote:
> It's not. But if the unwind library can't handle something, then
the _Unwind_Resume_or_Rethrow could fall out of the function (it would assert in
debug mode). Darwin's implementation of _URoR in libunwind does this.
>
>    
Isn't unwind library supposed to call terminate() every time it can't 
handle something?

Yuri

On Jul 15, 2010, at 6:52 PM, Yuri wrote:
> On 07/15/2010 18:30, Bill Wendling wrote:
>> It's not. But if the unwind library can't handle something,
then the _Unwind_Resume_or_Rethrow could fall out of the function (it would
assert in debug mode). Darwin's implementation of _URoR in libunwind does
this.
>> 
> Isn't unwind library supposed to call terminate() every time it
can't handle something?
> 
I don't see anything specifying that it should call terminate() in the
exception ABI document:

	http://www.codesourcery.com/public/cxx-abi/abi-eh.html

-bw