// mapzero ensures that zeroptr points to a buffer large enough to
// serve as the zero value for t.
func mapzero(t *_type) {
// Is the type small enough for existing buffer?
cursize := uintptr(atomic.Loadp(unsafe.Pointer(&zerosize)))
if t.size <= cursize {
return
}
// Allocate a new buffer.
lock(&zerolock)
cursize = uintptr(atomic.Loadp(unsafe.Pointer(&zerosize)))
if cursize < t.size {
for cursize < t.size {
cursize *= 2
if cursize == 0 {
// need >2GB zero on 32-bit machine
throw("map element too large")
}
}
atomic.Storep1(unsafe.Pointer(&zeroptr), persistentalloc(cursize, 64, &memstats.other_sys))
atomic.Storep1(unsafe.Pointer(&zerosize), unsafe.Pointer(zerosize))
}
unlock(&zerolock)
}
//go:linkname sync_atomic_StorePointer sync/atomic.StorePointer
//go:nosplit
func sync_atomic_StorePointer(ptr *unsafe.Pointer, new unsafe.Pointer) {
sync_atomic_StoreUintptr((*uintptr)(unsafe.Pointer(ptr)), uintptr(new))
atomic.Storep1(noescape(unsafe.Pointer(ptr)), new)
writebarrierptr_nostore((*uintptr)(unsafe.Pointer(ptr)), uintptr(new))
}
//go:nosplit
func atomicstorep(ptr unsafe.Pointer, new unsafe.Pointer) {
atomic.Storep1(noescape(ptr), new)
writebarrierptr_nostore((*uintptr)(ptr), uintptr(new))
}