//go:nosplit
func casp(ptr *unsafe.Pointer, old, new unsafe.Pointer) bool {
if !atomic.Casp1((*unsafe.Pointer)(noescape(unsafe.Pointer(ptr))), noescape(old), new) {
return false
}
writebarrierptr_nostore((*uintptr)(unsafe.Pointer(ptr)), uintptr(new))
return true
}
//go:nosplit
func casp(ptr *unsafe.Pointer, old, new unsafe.Pointer) bool {
// The write barrier is only necessary if the CAS succeeds,
// but since it needs to happen before the write becomes
// public, we have to do it conservatively all the time.
writebarrierptr_prewrite((*uintptr)(unsafe.Pointer(ptr)), uintptr(new))
return atomic.Casp1((*unsafe.Pointer)(noescape(unsafe.Pointer(ptr))), noescape(old), new)
}
// bv describes the memory starting at address scanp.
// Adjust any pointers contained therein.
func adjustpointers(scanp unsafe.Pointer, cbv *bitvector, adjinfo *adjustinfo, f *_func) {
bv := gobv(*cbv)
minp := adjinfo.old.lo
maxp := adjinfo.old.hi
delta := adjinfo.delta
num := bv.n
// If this frame might contain channel receive slots, use CAS
// to adjust pointers. If the slot hasn't been received into
// yet, it may contain stack pointers and a concurrent send
// could race with adjusting those pointers. (The sent value
// itself can never contain stack pointers.)
useCAS := uintptr(scanp) < adjinfo.sghi
for i := uintptr(0); i < num; i++ {
if stackDebug >= 4 {
print(" ", add(scanp, i*sys.PtrSize), ":", ptrnames[ptrbit(&bv, i)], ":", hex(*(*uintptr)(add(scanp, i*sys.PtrSize))), " # ", i, " ", bv.bytedata[i/8], "\n")
}
if ptrbit(&bv, i) == 1 {
pp := (*uintptr)(add(scanp, i*sys.PtrSize))
retry:
p := *pp
if f != nil && 0 < p && p < _PageSize && debug.invalidptr != 0 {
// Looks like a junk value in a pointer slot.
// Live analysis wrong?
getg().m.traceback = 2
print("runtime: bad pointer in frame ", funcname(f), " at ", pp, ": ", hex(p), "\n")
throw("invalid stack pointer")
}
if minp <= p && p < maxp {
if stackDebug >= 3 {
print("adjust ptr ", p, " ", funcname(f), "\n")
}
if useCAS {
ppu := (*unsafe.Pointer)(unsafe.Pointer(pp))
if !atomic.Casp1(ppu, unsafe.Pointer(p), unsafe.Pointer(p+delta)) {
goto retry
}
} else {
*pp = p + delta
}
}
}
}
}
// Here for gccgo until we port atomic_pointer.go and mgc.go.
//go:nosplit
func casp(ptr *unsafe.Pointer, old, new unsafe.Pointer) bool {
if !atomic.Casp1((*unsafe.Pointer)(noescape(unsafe.Pointer(ptr))), noescape(old), new) {
return false
}
return true
}