llvm dev - Feb 2010 - [LLVMdev] Disabling rtti on default build - could it be reverted/re-enabled?

Jeffrey Yasskin wrote:
> I've put together http://llvm.org/docs/Packaging.html to document
> these kinds of requests for all packagers in one place. Let me know if
> any of the advice I've put there is wrong. (At the moment,
Looks good to me. BTW exception support for LLVM is not required
to link with code that uses exceptions. At least our toolset
seems to link fine with LLVM without this flag given for make and
it uses exceptions all over the place. So probably it's not required
to be on for the binary packages either (not sure about this).

About --enable-shared. Could it be a good compromise to allow to
link the LLVM tools statically (for the startup speedup) but still
generate also a shared lib for external projects to more easily link
with? So, by default always (additionally to the static lib) generate
the big .so but only when --link-llvm-with-shared (or similar)
is given it would link the LLVM binaries with it?

-- 
--PJ

Pekka Jääskeläinen wrote:
> Jeffrey Yasskin wrote:
>> I've put together http://llvm.org/docs/Packaging.html to document
>> these kinds of requests for all packagers in one place. Let me know if
>> any of the advice I've put there is wrong. (At the moment,
>
> Looks good to me. BTW exception support for LLVM is not required
> to link with code that uses exceptions. At least our toolset
> seems to link fine with LLVM without this flag given for make and
> it uses exceptions all over the place. So probably it's not required
> to be on for the binary packages either (not sure about this).
The reason we can't turn RTTI off for VMCore right now is that it breaks 
the build on Mac of tools/bugpoint which uses RTTI (because it uses 
exceptions). Your ABI may vary.

Nick
> About --enable-shared. Could it be a good compromise to allow to
> link the LLVM tools statically (for the startup speedup) but still
> generate also a shared lib for external projects to more easily link
> with? So, by default always (additionally to the static lib) generate
> the big .so but only when --link-llvm-with-shared (or similar)
> is given it would link the LLVM binaries with it?
>

On Fri, Feb 26, 2010 at 11:04 AM, Nick Lewycky <nicholas at mxc.ca>
wrote:
> Pekka Jääskeläinen wrote:
>>
>> Jeffrey Yasskin wrote:
>>>
>>> I've put together http://llvm.org/docs/Packaging.html to
document
>>> these kinds of requests for all packagers in one place. Let me know
if
>>> any of the advice I've put there is wrong. (At the moment,
>>
>> Looks good to me. BTW exception support for LLVM is not required
>> to link with code that uses exceptions. At least our toolset
>> seems to link fine with LLVM without this flag given for make and
>> it uses exceptions all over the place. So probably it's not
required
>> to be on for the binary packages either (not sure about this).
>
> The reason we can't turn RTTI off for VMCore right now is that it
breaks the
> build on Mac of tools/bugpoint which uses RTTI (because it uses
exceptions).
> Your ABI may vary.
That's RTTI, not exceptions. If both had RTTI on, but bugpoint used
exceptions and VMCore didn't, Pekka's saying it would still link
(which seems, actually, to be the current state of the world). I'll
remove the REQUIRES_EH item.

On Fri, Feb 26, 2010 at 11:02 AM, Pekka Jääskeläinen
<pekka.jaaskelainen at tut.fi> wrote:
> About --enable-shared. Could it be a good compromise to allow to
> link the LLVM tools statically (for the startup speedup) but still
> generate also a shared lib for external projects to more easily link
> with? So, by default always (additionally to the static lib) generate
> the big .so but only when --link-llvm-with-shared (or similar)
> is given it would link the LLVM binaries with it?
It would be straightforward to add another option controlling how the
tools are linked (I'm not planning to do it, but you can), but
building the shared library by default broke things on ARM, darwin-8,
and apple's internal builds. That's why it's off by default.