I'm trying to compile Cobalt and getting errors building cpu_features_get.cc. The specific version I'm building is here: https://github.com/Metrological/cobalt/blob/master/src/starboard/shared/linux/cpu_features_get.cc and it appears to be based on Cobalt 22. I'm building using stbgcc-6.3.18, only Ubuntu 20.04. Sysroot is set to the cross compiler. And I'm building the starboard port at https://github.com/Metrological/cobalt/tree/master/src/third_party/starboard/wpe/brcm/arm, for ARM64.
An example of the error:
cpu_features_get.cc:381:12: error: 'HWCAP_SET_FOR_ARMV8' was not declared in this scope
There follow others, all related to HWCAP #defines.
As far as I can tell, the file defines these values if:
53: #if SB_IS(32_BIT) || defined(ANDROID)
Neither of these is true - I am compiling for ARM64 on Linux.
The code using HWCAP_SET_FOR_ARMV8 and the other missing defines is conditionally compiled as well:
340: #if SB_IS(ARCH_ARM) || SB_IS(ARCH_ARM64)
...
// Construct hwcap bitmask by the feature flags in /proc/cpuinfo
uint32_t ConstructHwcapFromCPUInfo(ProcCpuInfo* cpu_info,
int16_t architecture_generation,
uint32_t hwcap_type) {
if (hwcap_type == AT_HWCAP && architecture_generation >= 8) {
// This is a 32-bit ARM binary running on a 64-bit ARM64 kernel.
// The 'Features' line only lists the optional features that the
// device's CPU supports, compared to its reference architecture
// which are of no use for this process.
SB_LOG(INFO) << "Faking 32-bit ARM HWCaps on ARMv"
<< architecture_generation;
return HWCAP_SET_FOR_ARMV8;
}
...
...
So ARCH_ARM64 is true, and this code is compiled. But the defines are missing because it's not 32-bit. This seems contradictory and to my eyes could never have worked. How is it possible to compile Cobalt for ARM64?
