llvm dev - Dec 2015 - -fno-rtti compilation option

Hi all,

Sorry to bother you guys with this question coming from a young beginner, but
even after some hours of research, I could not find any way to solve my issue...

I have a project using LLVM APIs (3.7.0), so I compile it with options suggested
by 'llvm-config -cxxflags', including -fno-rtti. Without this latter
option, the build fails ("no reference to typeinfo...").
However, I also test my code thanks to CppUnit, which does not allow this
compilation option (since it uses some functions such as 'typeid').

This sounds annoying... Has anyone already encountered such an issue? How did
you manage with that?

Thanks a lot in advance!

Yours, sincerely,

AD

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On 2 Dec 2015, at 15:20, Adrien DEGRANGE via llvm-dev <llvm-dev at
lists.llvm.org> wrote:
> 
> This sounds annoying… Has anyone already encountered such an issue? How did
you manage with that?
I found this issue, but it was too late to get a fix in to 3.7.  The issue is
that a number of classes in public headers don’t have an anchor method and so
get emitted in every compilation unit, and their vtable refers to the type_info
in the superclass (if that compilation unit has RTTI enabled), which doesn’t
exist.

The work-around that we use is to build LLVM with RTTI enabled.

David

Hi David,

Thanks a lot for your answer, I got it! 

I'll try this workaround asap.

Have a great day,

AD

Adrien Dégrange 
Recherche & Développement
invoke-software.fr






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-----Message d'origine-----
De : Dr D. Chisnall [mailto:dc552 at hermes.cam.ac.uk] De la part de David
Chisnall
Envoyé : mercredi 2 décembre 2015 16:23
À : Adrien DEGRANGE <adegrange at invoke.fr>
Cc : llvm-dev at lists.llvm.org
Objet : Re: [llvm-dev] -fno-rtti compilation option

On 2 Dec 2015, at 15:20, Adrien DEGRANGE via llvm-dev <llvm-dev at
lists.llvm.org> wrote:
> 
> This sounds annoying… Has anyone already encountered such an issue? How did
you manage with that?
I found this issue, but it was too late to get a fix in to 3.7.  The issue is
that a number of classes in public headers don’t have an anchor method and so
get emitted in every compilation unit, and their vtable refers to the type_info
in the superclass (if that compilation unit has RTTI enabled), which doesn’t
exist.

The work-around that we use is to build LLVM with RTTI enabled.

David