Re: [PATCH] libgloss: arm: break newlib dependency

[Corinna Vinschen <vinschen@redhat.com>]

On Dec 20 20:47, Mike Frysinger wrote:
> On 19 Dec 2022 10:08, Richard Earnshaw wrote:
> > On 14/12/2022 09:13, Mike Frysinger wrote:
> > > The libgloss port has been reaching back into newlib internals for a
> > > single header whose contents have been frozen for almost a decade.
> > > To break this backwards libgloss->newlib dependency, duplicate that
> > > header here so we can keep libgloss independent as it's meant to be.
> > 
> > This isn't really 'newlib internals', it's a header file that tries to 
> > provide ACLE[1] compatibility for older versions of GCC that lacked such 
> > support.  Having two copies of this is a maintenance burden, so I'm not 
> > entirely sure this is a great thing to do, even if the copies are 
> > supposed to be identical.
> 
> newlib already has 2 itself.  so this will be a 3rd.  i don't disagree with
> the maintenance concern, but the fact the file hasn't changed in a decade,
> and seems unlikely to ever change, makes me not worry about it.
> 
> > If we can agree on a common location in the source tree that both newlib 
> > and libgloss can pull this from, then I'm happy to move it if that would 
> > make you happier.
> 
> libgloss is supposed to be C library agnostic.  the C library (newlib) itself
> relies on the output of libgloss (e.g. the crt and low level syscalls).  since
> there is no other tree/project in play that i'm aware of, that means there are
> really only three options:
> * have the compiler provide it
> * have libgloss provide it (and newlib uses that)
> * duplicate the header
> 
> i know the libgloss/newlib separation is still pretty unclean due to the two
> projects historically being one (i.e. everything in newlib), but i don't think
> that's a good reason to keep it messy with libgloss depending on newlib.
> -mike

Why not just <toplevel>/include then?  It already contains target-specific
stuff in the opcodes subdir, or the xtensa headers.  Having to share them
between newlib and libgloss should be reason enough to move the file there.


Corinna