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Re: powerpc new PLT and GOT

Alan Modra wrote:
> This is where I'm at with gcc support for the new powerpc-linux PLT/GOT
> layout (see
> I'm not asking for commit approval yet;  That ought to wait until I've
> thrown together glibc support as well so this can all be tested properly,
> but what I have here seems to do the right thing.  So I'm looking for
> comments like "That's the Wrong Way.  You ought to ..."

Not everyone who uses ABI_V4 uses glibc.  Two, one might try to use
the new compiler/binutils on an older system who's dynamic loader doesn't
support the new PLT/GOT mechanism.

> Some things I know need attention:
> a) Should the new -fpic PLT/GOT code support be enabled by default?  The
>    linker  will continue to generate the old GOT/PLT layout until a new
>    glibc is available, a consequence of a "bl got-4" used in the current
>    crti.o.  This is fortunate, and means we don't need to do a configure
>    test on glibc to figure whether the new PLT/GOT code is safe to use.
>    However, the new GOT pointer load sequence is larger, (but might be
>    quicker) and new PLT calls always need the GOT pointer, so code
>    increases a little in size.

As I said before, the issue isn't the linker but the dynamic loader.
Unless you do a configure time to see if the dynamic loader does
the right thing I don't see how you can enable it by default.

Matt Thomas                     email:
3am Software Foundry              www:
Cupertino, CA              disclaimer: I avow all knowledge of this message.

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