Magic-Mirror/llvm-capstone
1
0
Fork 0
mirror of https://github.com/capstone-engine/llvm-capstone.git synced 2025-02-22 03:03:43 +00:00
Code Issues Actions 2 Packages Projects Releases Wiki Activity

[builtins][FMV][Apple] Use builtin atomic load/store, instead of libdispatch (#78807)

Browse Source
This commit is contained in:
Jon Roelofs 2024-01-22 09:10:16 -08:00 committed by GitHub
parent 43b13341fb
commit c083b38007
No known key found for this signature in database
GPG Key ID: B5690EEEBB952194
1 changed files with 15 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

28
compiler-rt/lib/builtins/cpu_model/aarch64/fmv/apple.inc
View File

@ -14,19 +14,17 @@ static bool isKnownAndSupported(const char *name) {
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.
// ELF platforms, where IFuncs are resolved serially at load time). This
// function's effect on __aarch64_cpu_features must be idempotent.
if (!__atomic_load_n(&__aarch64_cpu_features.features, __ATOMIC_RELAXED)) {
uint64_t features = 0;
static dispatch_once_t onceToken = 0;
dispatch_once(&onceToken, ^{
// https://developer.apple.com/documentation/kernel/1387446-sysctlbyname/determining_instruction_set_characteristics
static const struct {
const char *sysctl_name;
enum CPUFeatures feature;
} features[] = {
} feature_checks[] = {
{"hw.optional.arm.FEAT_FlagM", FEAT_FLAGM},
{"hw.optional.arm.FEAT_FlagM2", FEAT_FLAGM2},
{"hw.optional.arm.FEAT_FHM", FEAT_FP16FML},
@ -58,12 +56,16 @@ void __init_cpu_features_resolver(void) {
{"hw.optional.arm.FEAT_BTI", FEAT_BTI},
};
for (size_t I = 0, E = sizeof(features) / sizeof(features[0]); I != E; ++I)
if (isKnownAndSupported(features[I].sysctl_name))
__aarch64_cpu_features.features |= (1ULL << features[I].feature);
for (size_t I = 0, E = sizeof(feature_checks) / sizeof(feature_checks[0]);
I != E; ++I)
if (isKnownAndSupported(feature_checks[I].sysctl_name))
features |= (1ULL << feature_checks[I].feature);
__aarch64_cpu_features.features |= (1ULL << FEAT_INIT);
});
features |= (1ULL << FEAT_INIT);
__atomic_store(&__aarch64_cpu_features.features, &features,
__ATOMIC_RELAXED);
}
}
#endif // TARGET_OS_OSX || TARGET_OS_IPHONE