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SubjectRe: PROC macro to annotate functions in assembly files
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On Thu, 18 Dec 2008 11:44:27 +0000, "Russell King"
<rmk+lkml@arm.linux.org.uk> said:
> On Wed, Dec 17, 2008 at 12:12:14PM +0100, Alexander van Heukelum wrote:
> > Yeah, assembly files contain some interesting nesting. In this
> > particular case I think the solution is simple... Just use PROC
> > and ENDPROC around the complete functions, and leave the explicit
> > .global's for the additional entry points.
> I'm sorry, that doesn't work in all cases.
>
> On ARM with later toolchains, there's additional metadata associated with
> every symbol, and it's beginning to matter getting this right. That
> metadata includes whether it's a function, and more importantly whether
> the code pointed to by the symbol is Thumb or ARM.
>
> This leads to:
>
> ENTRY(__ashldi3)
> ENTRY(__aeabi_llsl)
>
> ...
>
> ENDPROC(__ashldi3)
> ENDPROC(__aeabi_llsl)
>
> and we want both of those symbols to have exactly the same attributes.
>
> Merely adding a .globl for the second name doesn't do that. It needs
> .globl, .size, and .type.
>
> So what you're actually talking about using your approach is enforcing
> the pairing of the existing ENTRY/ENDPROC and open coding everything
> else.

Note that enforcing the pairing will be enabled by ARCH code. Is the
construct you show here (two symbols covering identical code) the only
problem you forsee? I don't want to introduce too many macro's to
handle special cases, but this one should be solved.

> Forgive me if I think this is a backward step. It certainly seems to
> add some insane restrictions.

Some restrictions are introduced, indeed. And I agree that evading the
checking framework by doing things manually should be avoided.

Greetings,
Alexander

> --
> Russell King
> Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/
> maintainer of:
--
Alexander van Heukelum
heukelum@fastmail.fm

--
http://www.fastmail.fm - The way an email service should be



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