Re: [rfc] towards a defined abi for libgfortran

[Andrew Pinski <pinskia at physics dot uc dot edu>]

On Dec 6, 2004, at 8:18 PM, Andrew Pinski wrote:

> On Dec 6, 2004, at 7:41 PM, Richard Henderson wrote:
>
> > A prerequisite for being able to point to an ABI is symbol access 
> > control.
> > Namely, you don't want to expose any symbols that you don't mean to 
> > expose.
> >
> > The following patch replaces the prefix macro with a set of fine-grain
> > macros that do allow us to control which symbols are seen by user 
> > apps.
> >
> > On elf systems, it will use __attribute__((visibility("hidden"))) to
> > prevent specific symbols from escaping the library.  It will also use
> > __attribute__((alias(...))) to reduce the number of PLT entries needed
> > when calling routines that we do intend to export.
> > Comments?
>
> I will test this on darwin which has visibility("hidden") but not 
> alias.

This failed but due to a compiler bug.
The following code is not able to compile on darwin because
the target says options is defined when it is not because it is
a common symbol.

int options  __attribute__((__visibility__("hidden")));

void f(void)
{
  options = 0;
}

I will look into fixing this and test the patch again.  This is a
regression from when Mark rewrote part of the darwin backend.

Thanks,
Andrew Pinski