ARM_ARCH_8A

[a-w50]

Hi,

when I'm trying to cross-compile rapidyaml with an armv8 compiler, it does

#define __ARM_ARCH_8A__ 1 and not #define __ARM_ARCH_8__ 1.

The cpu.hpp in this library only checks for ARM_ARCH_8, which is not set in my case and hence it breaks. I'm not sure if this is just a typo here or if ARM_ARCH_8 really exists, but looking at openssl (https://github.com/openssl/openssl/blob/master/crypto/arm_arch.h) it also only checks for ARM_ARCH_8A.

[biojppm]

ATM I'm working with c4core on an armv8a 64bit platform and c4core definitely works there. I guess yours is 32bit?

Looking at what cpu.hpp does:

   #if defined(__aarch64__) || defined(_M_ARM64)
       #define C4_CPU_ARM64
       #define C4_CPU_ARMV8
       #define C4_WORDSIZE 8
   #else
       #define C4_CPU_ARM
       #define C4_WORDSIZE 4
       #if defined(__ARM_ARCH_8__) || (defined(__TARGET_ARCH_ARM) && __TARGET_ARCH_ARM >= 8)
           #define C4_CPU_ARMV8
//...

What happens if you add defined(__ARM_ARCH_8A__) to the 32 bit check? Does it fix your problem? Happy to accept a PR to address this.

[a-w50]

Right now, I'm add_compile_definitions(__ARM_ARCH_8__) to make it work again. Here is the output of my toolchains gcc

echo | ./crosstool/bin/armv8-rpi4-linux-gnueabihf-gcc -dM -E - | grep ARM
#define __ARM_SIZEOF_WCHAR_T 4
#define __ARM_FEATURE_SAT 1
#define __ARM_ARCH_ISA_ARM 1
#define __ARM_NEON 1
#define __ARMEL__ 1
#define __ARM_FP 14
#define __ARM_ARCH_8A__ 1
#define __ARM_NEON_FP 6
#define __ARM_FEATURE_IDIV 1
#define __ARM_SIZEOF_MINIMAL_ENUM 4
#define __ARM_PCS_VFP 1
#define __ARM_FEATURE_FMA 1
#define __ARM_FEATURE_LDREX 15
#define __ARM_FEATURE_UNALIGNED 1
#define __ARM_FEATURE_QBIT 1
#define __ARM_NEON__ 1
#define __ARM_ARCH_PROFILE 65
#define __ARM_32BIT_STATE 1
#define __ARM_FEATURE_CLZ 1
#define __ARM_ARCH_ISA_THUMB 2
#define __ARM_ARCH 8
#define __ARM_FEATURE_SIMD32 1
#define __ARM_FEATURE_CRC32 1
#define __ARM_FEATURE_DSP 1
#define __ARM_ARCH_EXT_IDIV__ 1
#define __ARM_EABI__ 1

Its a toolchain, build with crosstool-ng for raspberrypi4. What toolchain are you using and what is it's output of definitions?

Definitely adding defined(__ARM_ARCH_8A__) will solve the problem, I was just wondering if there is any compiler, setting __ARM_ARCH_8__

[biojppm]

On my side, I wrote this block of code many years ago and don't recall exactly why ARM_ARCH_8 is there.

But from a quick search, there is a mention to ARM_ARCH_8 in here, so it is not widely off the mark.

OTOH, on the same search I noticed this has only ARM64_ARCH_8. And no reference either in this.

Also, from the dump you provide, I notice the existing check (defined(__TARGET_ARCH_ARM) && __TARGET_ARCH_ARM >= 8) would work if it was actually (defined(__ARCH_ARM) && __ARCH_ARM >= 8).

So I'll submit a fix with both. I think it makes sense.

[a-w50]

Thanks! 💯