Re: [PATCH] u-boot.inc: properly specify CC for EXTRA_OEMAKE

[Tom Rini <trini@konsulko.com>]

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On Tue, Nov 10, 2015 at 07:59:03PM -0800, Khem Raj wrote:
> 
> > On Nov 10, 2015, at 5:09 AM, Tom Rini <trini@konsulko.com> wrote:
> > 
> > On Thu, Nov 05, 2015 at 03:23:48PM +0100, Carlos Rafael Giani wrote:
> >> On 11/05/2015 03:22 PM, Otavio Salvador wrote:
> >>> Hello Carlos,
> >>> 
> >>> On Thu, Nov 5, 2015 at 11:16 AM, Carlos Rafael Giani
> >>> <dv@pseudoterminal.org> wrote:
> >>>> So, this is because of the TOOLCHAIN_OPTIONS ?
> >>>> Also, what about the ${CC} ? Right now it won't work properly with clang for
> >>>> example.
> >>> The clang is problem might involve us to rework something but all this
> >>> needs to be based on last U-Boot releases; we shouldn't put
> >>> workarounds and hacks on OE-Core without good reasons.
> >>> 
> >>> Has the clang been tested with 2015.10?
> >> 
> >> Still, then I'd add something to output an error message like
> >> "U-Boot can only be compiled with gcc". Right now, the error
> >> messages that would occur would be highly confusing and misleading.
> > 
> > U-Boot supports clang, but it's not as well tested as other things.
> > However, this patch is still wrong as we do not want to try and force
> > flags to gcc, just like we don't with the kernel.  For more on U-Boot,
> > see doc/README.clang (And then possibly do some fixups, I'm not having
> > super luck with it right now, but I'm in a bit of a rush right now).
> > 
> 
> This patch is however injecting flags externally, so in case you were to use
> clang with OE in context the TOOLCHAIN_OPTION will be appropriately set as well
> so this should work fine. As far as u-boot’s own build architecture is concerned
> its fine. I think the real problem is arising due to toolchain defaults in OE
> e.g. when we default to hard float gcc does not really use hard-float unless specified on commandline. One can argue that OE should be fixed for that or gcc
> should be using the right ABI as default which corresponds to default configs as used for gcc in toolchain.
> 
> One concern here I have is that when we switch float-abi like this, what is the impact on u-boot itself, has it ever been build and tested with hard-float, as long as there are no float function arguments this should not do anything to code
> but then we need report on this. 

First, no, like the kernel, you do not go mucking with the float options
that U-Boot wants to use.  OE is correctly today letting U-Boot enforce
what it wants (and then from time to time exposing latent bug from cases
where the toolchain ends up overriding us).

Second, it's currently a bit of a moot point as U-Boot for clang for ARM
needs a bit of attention again as how we deal with global data is once
again making clang unhappy and no one has gone and fixed it again.

-- 
Tom

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