[Buildroot] [PATCH] package/binutils: Disable -Os for Thumb-2 only platforms

[Romain Naour]

Hi Thomas,

Le 04/09/2016 à 14:43, Thomas Petazzoni a écrit :
> Hello,
> 
> On Sun,  4 Sep 2016 10:49:50 +0200, Romain Naour wrote:
> 
>> +# Workaround a build issue with -Os on Thumb-2 only platforms
>> +# (such as Cortex-M). (Binutils 2.25.1 and 2.26.1)
>> +ifeq ($(BR2_ARM_CPU_HAS_ARM)$(BR2_OPTIMIZE_S),yy)
> 
> Unless I'm missing something, I don't see how the code is matching the
> comment above. Your comment is "with Thumb-2 only platforms, there is
> an issue with the -Os optimization level" while your condition is "with
> ARM-capable platforms, there is an issue with the -Os optimization
> level".
> 
> Are you sure what want is not:
> 
> ifeq ($(BR2_ARM_CPU_HAS_ARM):$(BR2_OPTIMIZE_S),:y)
> ....
> endif

You're right, this is what I wanted to do. :-/

> 
> Also, I'm a bit surprised this happens only on Thumb-2 only platforms,
> and not on all ARM platforms, when Thumb-2 is chosen. But I'm far from
> understanding all the fine details of relocations.

Neither do I.
I tried with an ARM toolchain with BR2_ARM_INSTRUCTIONS_THUMB2 set and with the
same build options (static only and Os) but Binutils build fine.

I'll send a v2 shortly.

Best regards,
Romain

> 
> Thanks,
> 
> Thomas
>