r188906 - Centralize the handling of -target-feature.

[Rafael Espíndola]

r195551

On 29 October 2013 00:03, Rafael Espíndola <rafael.espindola at gmail.com> wrote:
> On 28 October 2013 23:28, Lang Hames <lhames at gmail.com> wrote:
>> Hi Rafael,
>>
>> I noticed that as a consequence of this patch, clang is issuing the
>> following warning when assembling for arm:
>>
>> "'+soft-float-abi' is not a recognized feature for this target (ignoring
>> feature)"
>>
>> You can reproduce this (at least on Darwin, and I expect on Linux too) by
>> creating an empty foo.s file and running:
>>
>> clang -arch armv7 -c foo.s
>>
>> It looks like the cause of the warning is that both Clang::ConstructJob and
>> ClangAs::ConstructJob are both calling getARMTargetFeatures (indirectly via
>> getTargetFeatures), and getARMTargetFeatures always adds the abi-appropriate
>> flag, even when the driver was being invoked as an assembler.
>>
>> I'm not very familiar with the driver code, so I didn't want to jump in and
>> undo any of the useful parts of your refactor to fix this.
>>
>> Do you have any thoughts on the right way to omit this flag when assembling?
>
> Good question. These are odd "feature, but not really". It looks like
> the driver passes them as features because that is all that TargetInfo
> in "clang -cc1" will see. Some options would be
>
> * Don't pass this information as features. Call them TargetOptions or
> something like that and add a  virtual bool handleTargetOption.
> * Make them real features (attached patch).
> * Pass a flag to getARMTargetFeatures so that it knows the target
> features are being collected for the assembler.
>
> Daniel, you added this back in r91755 along with the "this is a hack"
> FIXME. What was the direction you wanted this to take?
>
> Cheers,
> Rafael