llvm dev - May 2011 - [LLVMdev] Exception handling with the LLVM makefile system

Hi all,

I'm having trouble when trying to reuse some functions that use 
Boost::Exception into my LLVM-based application. As far as I know, LLVM 
turns off Exception handling (apparently for performance reasons), so I 
get the following link-time error in a few places:

"undefined reference to `boost::throw_exception(std::exception
const&)"

When I compile the external code from outside the LLVM Makefile system, 
everything goes well. Is it possible to enable exception handling for 
some parts of the compilation? Just like turning on RTTI with 
"REQUIRES_RTTI=1" ? Removing exception handling from the functions is 
not an option, since I would have to tweak the Boost library internals.

Thanks ahead!

-- 
Pablo Barrio
Dpto. Ing. Electrónica - E.T.S.I. Telecomunicación
Despacho C-203
Avda. Complutense s/n, 28040 Madrid
Tlf. 915495700 ext. 4234
@: pbarrio at die.upm.es

On 16.05.2011, at 08:44, Pablo Barrio wrote:
> Hi all,
> 
> I'm having trouble when trying to reuse some functions that use 
> Boost::Exception into my LLVM-based application. As far as I know, LLVM 
> turns off Exception handling (apparently for performance reasons), so I 
> get the following link-time error in a few places:
> 
> "undefined reference to `boost::throw_exception(std::exception
const&)"
> 
> When I compile the external code from outside the LLVM Makefile system, 
> everything goes well. Is it possible to enable exception handling for 
> some parts of the compilation? Just like turning on RTTI with 
> "REQUIRES_RTTI=1" ? Removing exception handling from the
functions is
> not an option, since I would have to tweak the Boost library internals.
Whatever the LLVM side of things, boost::throw_exception is a function that you,
the user, have to implement when disabling exceptions. It's basically the
"I want to throw an exception, so what should I really do?" callback.

Sebastian

On 05/16/2011 05:11 PM, Sebastian Redl wrote:
> On 16.05.2011, at 08:44, Pablo Barrio wrote:
>
>> Hi all,
>>
>> I'm having trouble when trying to reuse some functions that use
>> Boost::Exception into my LLVM-based application. As far as I know, LLVM
>> turns off Exception handling (apparently for performance reasons), so I
>> get the following link-time error in a few places:
>>
>> "undefined reference to `boost::throw_exception(std::exception
const&)"
>>
>> When I compile the external code from outside the LLVM Makefile system,
>> everything goes well. Is it possible to enable exception handling for
>> some parts of the compilation? Just like turning on RTTI with
>> "REQUIRES_RTTI=1" ? Removing exception handling from the
functions is
>> not an option, since I would have to tweak the Boost library internals.
> Whatever the LLVM side of things, boost::throw_exception is a function that
you, the user, have to implement when disabling exceptions. It's basically
the "I want to throw an exception, so what should I really do?"
callback.
>
> Sebastian
That's right, I wrote a throw_exception() function with the sole purpose 
of avoiding error messages. However, I'm not really an expert on 
exception handling: the function just prints out an error message. 
boost::throw_exception allows handling exceptions just as when using the 
C++ builtin "throw" features. The selection of either method is done
by
defining BOOST_NO_EXCEPTIONS. I'd like to use the standard exceptions 
instead of making my own. Do you think that's possible? Is it possible 
(and correct) to turn on exception handling with LLVM?

-- 
Pablo Barrio
Dpto. Ing. Electrónica - E.T.S.I. Telecomunicación
Despacho C-203
Avda. Complutense s/n, 28040 Madrid
Tlf. 915495700 ext. 4234
@: pbarrio at die.upm.es