On Wed, Apr 23, 2014 at 07:51:54AM +0900, Mike Hommey wrote:
> On Wed, Apr 23, 2014 at 10:41:06AM +1200, Robert O'Callahan wrote:
> > On Wed, Apr 23, 2014 at 1:25 AM, Benjamin Smedberg 
> > <benja...@smedbergs.us>wrote:
> > 
> > > On 4/22/2014 7:31 AM, Robert O'Callahan wrote:
> > >
> > >> It's all over the tree, inconsistently applied. Is it relevant anymore?
> > >> Can
> > >> we remove it entirely, or there some places where it's still relevant, 
> > >> and
> > >> if so, where ... XPCOM? Or should we be using it everywhere?
> > >>
> > >
> > > Short answer: I don't think it's relevant any more.
> > >
> > > Long answer: Each compiler and platform is a little different, so here's
> > > my take on where we are:
> > >
> > > * Windows/MSVC. NS_HIDDEN never had any effect; symbols are hidden by
> > > default and need dllexport to be exported
> > > * Mac/GCC or clang. We compile with -fvisibility=hidden. This means that
> > > all symbols are hidden by default and you need NS_EXPORT to mark them as
> > > exported/dynamic. Declarations are treated as dynamic. However because
> > > Mach-O executables use direct relocations, there is no actual difference
> > > between the generated code referencing a hidden or dynamic symbol, so 
> > > we're
> > > fine.
> > > * Linux/GCC or clang. We compile with #pragma visibility. This means that
> > > all symbols and declarations are treated as hidden by default and require
> > > NS_EXPORT if they are exported/dynamic.
> > >
> > 
> > On B2G and Android we're compiling with -fvisibility=hidden. configure
> > output says:
> > 
> > checking For gcc visibility bug with class-level attributes (GCC bug
> > 26905)... yes
> > checking For x86_64 gcc visibility bug with builtins (GCC bug 20297)... yes
> > 
> > Is that a problem?
> 
> No, that's just how we choose between #pragma visibility and
> -fvisibility=hidden

Well, its at least strange given the bugs mentioned in configure were
supposedly fixed in gcc 4.1, but I wouldn't be at all suprised if
investigating it finds the tests are wrong.

Trev

> 
> Mike
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