Re: [meta-oe][PATCH v2] abseil-cpp: add recipe for git version

[Sinan Kaya <okaya@kernel.org>]

On 2/10/2020 1:17 PM, Andrey Zhizhikin wrote:
>> +TARGET_CXXFLAGS += "${@bb.utils.contains('TARGET_ARCH', 'aarch64', '
>> -march=armv8-a+crypto', '', d)}"
> This cannot be enforced, as it would break those AArch64 derivatives,
> which does not have Crypto extension. See my comment above, where I
> extracted 2 sets of tune features for Cortex-A53. That means that
> there are SoCs there from different vendors, and some vendors decided
> to license Crypto extensions from ARM to include it in their RTL, but
> some opted out to save either space on a die or cost of the processor.
> 
> If you would base your build with '+crypto' unconditionally, then the
> binary would segfault on those SoCs which has Crypto opted out.
> 
> Moreover, enabling crypto extension in GCC automatically enables
> inlined NEON and VFP opcodes (see [1]), and there are more side
> effects to be expected on those SOCs which does not have those
> integrated.
> 

I agree. I dropped this line on v3.

I was curious about

TARGET_CXXFLAGS += "${@bb.utils.contains('TARGET_ARCH', 'x64', ' -maes
-msse4.1', '', d)}"

do we have a feature flag for this too?

Code doesn't compile without arch crypt support.