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Re: [PATCH] PPC64 elf configure
- From: "Steve Munroe" <sjmunroe at us dot ibm dot com>
- To: Roland McGrath <roland at redhat dot com>
- Cc: Alan Modra <amodra at bigpond dot net dot au>, libc-alpha <libc-alpha at sources dot redhat dot com>
- Date: Wed, 12 Mar 2003 15:09:56 -0600
- Subject: Re: [PATCH] PPC64 elf configure
Roland McGrath writes:
> Is there a reason this is impossible on PPC64? I would think that
values
> relative to the TOC address could work similarly to how they do on x86.
> Is this not doable, or is it just that the compiler doesn't do it? If
the
> latter, ideally GCC should learn to do it, and then we should write a
> configure check that ascertains if the compiler is in fact doing it.
It may not be impossible but it is difficult. The ABI allows for the
possibility of a GOT and small data area as a subset of the TOC, but I
don't think PPC64 gcc supports SDA. Or at least it's was not getting used
in the code generated for rtld.c.
The biggest issue is that we don't support TOCs >64KB and we tend to blow
the TOC on the larger libs. So putting more stuff into the TOC seems like
a bad idea.
Alan will have a give the details.
> I'm making your change for now anyway, since it's the safe default.
Thanks