================ @@ -0,0 +1,69 @@ +#include <TargetConditionals.h> +#if TARGET_OS_OSX || TARGET_OS_IPHONE +#include <dispatch/dispatch.h> +#include <sys/sysctl.h> + +static bool isKnownAndSupported(const char *name) { + int32_t val = 0; + size_t size = sizeof(val); + if (sysctlbyname(name, &val, &size, NULL, 0)) + return false; + return val; +} + +void __init_cpu_features_resolver(void) { + // On Darwin platforms, this may be called concurrently by multiple threads + // because the resolvers that use it are called lazily at runtime (unlike on + // ELF platforms, where IFuncs are resolved serially at load time). This + // function's effect on __aarch64_cpu_features should be idempotent, but even + // so we need dispatch_once to resolve the race condition. Dispatch is + // available through libSystem, which we need anyway for the sysctl, so this + // does not add a new dependency. + + static dispatch_once_t onceToken = 0; + dispatch_once(&onceToken, ^{ + // https://developer.apple.com/documentation/kernel/1387446-sysctlbyname/determining_instruction_set_characteristics + static struct { + const char *sysctl_name; + enum CPUFeatures feature; + } features[] = { ---------------- jroelofs wrote:
Ohh, I see you're asking a different question than I thought. Yeah, those three would probably be useful. Unfortunately, looks like we're just about out of bits in `__aarch64_cpu_features.features`. https://github.com/llvm/llvm-project/pull/75636 _______________________________________________ llvm-branch-commits mailing list llvm-branch-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-branch-commits