[LLVMdev] -fvisibility=hidden, and typeinfo, and type-erasure

[Rafael Avila de Espindola]

Sent from my iPhone

> On Jun 4, 2014, at 19:08, Joerg Sonnenberger <joerg at britannica.bec.de> wrote:
> 
>> On Wed, Jun 04, 2014 at 06:32:35PM -0400, Rafael Espíndola wrote:
>> I think the difference is actually in the c++ library. It looks like
>> libstdc++ changed to always use strcmp of the typeinfo names:
>> 
>> https://gcc.gnu.org/viewcvs/gcc?view=revision&revision=149964
>> 
>> Should we do the same with libc++?
> 
> No. It pessimizes correctly behaving code to work around code that
> violates the ELF ABI. Consider an application that loads plugins with
> RTLD_LOCAL. Two plugins implement a (hidden) type called "Plugin". The
> GCC change now makes this completely separate types identical for all
> RTTI purposes. That makes no sense at all.
> 

That is an interesting argument, in particular because RTLD_LOCAL seems to be the reason why libstdc++ switched :-)


> Joerg
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