llvm dev - Apr 2016 - [cfe-dev] [libunwind] __ELF__ macro for arm-none-eabi

On 16 April 2016 at 01:44, Zhao, Weiming via cfe-dev
<cfe-dev at lists.llvm.org> wrote:
> I'm building libunwind for ARM baremetal using clang.
> I notice that __ELF__ is used in libunwind and the macro is only defined
for
> Linux target on ARM.
> Should we also predefine that for arm-none-eabi target?
Do you mean in Clang's ARMTargetInfo::getTargetDefines() ?

I think so. I'm actually surprised it doesn't.

Copying Bradley and Silviu, as they were working on ACLE pre-processor
logic recently.

cheers,
--renato

This doesn't look like something ACLE specific (I can't find it in the
ACLE doc).

This seems to be a generic macro. I think it would make sense to define it
if we know we're emitting ELF.

Cheers,
Silviu

> -----Original Message-----
> From: Renato Golin [mailto:renato.golin at linaro.org]
> Sent: 16 April 2016 12:42
> To: Zhao, Weiming
> Cc: cfe-dev at lists.llvm.org Developers; LLVM Dev; Silviu Baranga; Bradley
> Smith
> Subject: Re: [cfe-dev] [libunwind] __ELF__ macro for arm-none-eabi
>
> On 16 April 2016 at 01:44, Zhao, Weiming via cfe-dev <cfe-dev at
lists.llvm.org>
> wrote:
> > I'm building libunwind for ARM baremetal using clang.
> > I notice that __ELF__ is used in libunwind and the macro is only
> > defined for Linux target on ARM.
> > Should we also predefine that for arm-none-eabi target?
>
> Do you mean in Clang's ARMTargetInfo::getTargetDefines() ?
>
> I think so. I'm actually surprised it doesn't.
>
> Copying Bradley and Silviu, as they were working on ACLE pre-processor
logic
> recently.
>
> cheers,
> --renato
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On 18 April 2016 at 16:18, Silviu Baranga <Silviu.Baranga at arm.com>
wrote:
> This doesn't look like something ACLE specific (I can't find it in
the ACLE doc).
Sorry, I didn't mean it was ACLE, only that you guys were fiddling
with macros. :)

> This seems to be a generic macro. I think it would make sense to define it
> if we know we're emitting ELF.
Since the EABI only mentions ELF format, and we even have an ELF EABI,
wouldn't it make sense to assume the format is ELF when we select
EABI? I mean, we emit ELF on EABI anyway...

GCC does the same, if that's any argument. :)

cheers,
--renato