[cfe-dev] Does clang support -fno-enforce-eh-specs option of gcc

Matthieu Monrocq matthieu.monrocq at gmail.com
Tue Nov 13 10:51:19 PST 2012


On Tue, Nov 13, 2012 at 7:44 PM, Konstantin Tokarev <annulen at yandex.ru>wrote:

>
> 13.11.2012, 22:39, "Devchandra L Meetei" <dlmeetei at gmail.com>:
> > Hi all
> > is the above flag supported.
>
> No.
>
> > Will also appreciate if some one can tell best practices to follow while
> using clang for reducing size of the resultant binaries?
>
> -Os -fno-rtti -fno-exceptions
>
> --
> Regards,
> Konstantin
>

I would note that this not exactly similar:

-fno-enforce-eh-specs
    Don't check for violation of exception specifications at runtime. This
option violates the C++ standard, but may be useful for reducing code size
in production builds, much like defining NDEBUG. The compiler will still
optimize based on the exception specifications.

This means that -fno-enforce-eh-specs let's you keep using exceptions.


A better alternative to `throw()` combined with `-fno-enforce-eh-specs` is
`noexcept` in C++11. If you throw, you are into undefined behavior land
because there is no runtime check.

I do not think there are similar alternatives when the exception
specification did precise a list of exceptions, but those are much rarer.

-- Matthieu
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