Re: [Buildroot] [PATCH] package/arm-gnu-a-toolchain: bump to version 10.3-2021.07

[Arnout Vandecappelle <arnout@mind.be>]

On 19/09/2021 15:09, Thomas Petazzoni wrote:
> Hello,
> 
> On Sun, 19 Sep 2021 14:35:56 +0200
> Arnout Vandecappelle <arnout@mind.be> wrote:
> 
>>> -ARM_GNU_A_TOOLCHAIN_VERSION = 9.2-2019.12
>>> -ARM_GNU_A_TOOLCHAIN_SITE = https://developer.arm.com/-/media/Files/downloads/gnu-a/$(ARM_GNU_A_TOOLCHAIN_VERSION)/binrel
>>> -ARM_GNU_A_TOOLCHAIN_SOURCE = gcc-arm-$(ARM_GNU_A_TOOLCHAIN_VERSION)-x86_64-arm-none-eabi.tar.xz
>>> +ARM_GNU_A_TOOLCHAIN_VERSION = 10.3-2021.07
>>> +ARM_GNU_A_TOOLCHAIN_SITE = https://developer.arm.com/-/media/Files/downloads/gnu-rm/$(ARM_GNU_A_TOOLCHAIN_VERSION)
>>> +ARM_GNU_A_TOOLCHAIN_SOURCE = gcc-arm-none-eabi-$(ARM_GNU_A_TOOLCHAIN_VERSION)-x86_64-linux.tar.bz2
>>
>>    Err, this can't be right... 'gnu-rm' stands for "GNU-based toolchain for
>> Cortex-R and Cortex-M", and "arm-none-eabi" means it's a toolchain without libc...
>>
>>    So either someone made a huge mistake at ARM, or you haven't actually tested
>> this patch :-)

  Or, of course, I can't read and I see 
toolchain/toolchain-external/toolchain-external-arm-arm instead of 
package/arm-gnu-a-toolchain...

  Worse still: I didn't see that the old one already *was* arm-none-eabi, it was 
just specified at the end of the tarball name instead of at the beginning.


> It was tested to build code for a Cortex-M4.
> 
> This package was originally introduced to build ARM 32-bit code in the
> context of TF-A (boot/arm-trusted-firmware/). At the very beginning,
> was submitted by a Marvell person, who also had to build code for a
> Cortex-M3 co-processor IIRC, but then was taken over by a person from
> Amarula, who needed it to build ARM 32-bit code running on a Cortex-A.
> 
> If it's truly a bare-metal toolchain with no libraries, it should not
> matter, right? You just pass to gcc -march=XYZ, and it will produce the
> right code. However, my understanding is that those bare-metal
> toolchains do have some libraries built for the target, which can
> potentially get linked with the code produced.

  Yeah, you get libgcc and libstdc++ from the gcc source. libstdc++ is probably 
not used . libgcc may not be linked in either if -nostdlib is used (which it 
probably is).


> So, long story short: do we need arm-gnu-a-toolchaind and
> arm-gnu-rm-toolchain packages ?

  Easy to check: build a bunch of the defconfigs which set 
BR2_TARGET_ARM_TRUSTED_FIRMWARE_NEEDS_ARM32_TOOLCHAIN=y. And maybe double-check 
if indeed ATF doesn't link with libgcc.

  Regards,
  Arnout
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