1 files changed, 96 insertions, 0 deletions
diff --git a/src/runtime/atomic_pointer.go b/src/runtime/atomic_pointer.go
new file mode 100644
index 0000000000..50a30242d9
--- /dev/null
+++ b/src/runtime/atomic_pointer.go
@@ -0,0 +1,96 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package runtime
+
+import "unsafe"
+
+// These functions cannot have go:noescape annotations,
+// because while ptr does not escape, new does.
+// If new is marked as not escaping, the compiler will make incorrect
+// escape analysis decisions about the pointer value being stored.
+// Instead, these are wrappers around the actual atomics (xchgp1 and so on)
+// that use noescape to convey which arguments do not escape.
+//
+// Additionally, these functions must update the shadow heap for
+// write barrier checking.
+
+//go:nosplit
+func atomicstorep(ptr unsafe.Pointer, new unsafe.Pointer) {
+	atomicstorep1(noescape(ptr), new)
+	writebarrierptr_nostore((*uintptr)(ptr), uintptr(new))
+	if mheap_.shadow_enabled {
+		writebarrierptr_noshadow((*uintptr)(noescape(ptr)))
+	}
+}
+
+//go:nosplit
+func xchgp(ptr unsafe.Pointer, new unsafe.Pointer) unsafe.Pointer {
+	old := xchgp1(noescape(ptr), new)
+	writebarrierptr_nostore((*uintptr)(ptr), uintptr(new))
+	if mheap_.shadow_enabled {
+		writebarrierptr_noshadow((*uintptr)(noescape(ptr)))
+	}
+	return old
+}
+
+//go:nosplit
+func casp(ptr *unsafe.Pointer, old, new unsafe.Pointer) bool {
+	if !casp1((*unsafe.Pointer)(noescape(unsafe.Pointer(ptr))), noescape(old), new) {
+		return false
+	}
+	writebarrierptr_nostore((*uintptr)(unsafe.Pointer(ptr)), uintptr(new))
+	if mheap_.shadow_enabled {
+		writebarrierptr_noshadow((*uintptr)(noescape(unsafe.Pointer(ptr))))
+	}
+	return true
+}
+
+// Like above, but implement in terms of sync/atomic's uintptr operations.
+// We cannot just call the runtime routines, because the race detector expects
+// to be able to intercept the sync/atomic forms but not the runtime forms.
+
+//go:linkname sync_atomic_StoreUintptr sync/atomic.StoreUintptr
+func sync_atomic_StoreUintptr(ptr *uintptr, new uintptr)
+
+//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))
+	atomicstorep1(noescape(unsafe.Pointer(ptr)), new)
+	writebarrierptr_nostore((*uintptr)(unsafe.Pointer(ptr)), uintptr(new))
+	if mheap_.shadow_enabled {
+		writebarrierptr_noshadow((*uintptr)(noescape(unsafe.Pointer(ptr))))
+	}
+}
+
+//go:linkname sync_atomic_SwapUintptr sync/atomic.SwapUintptr
+func sync_atomic_SwapUintptr(ptr *uintptr, new uintptr) uintptr
+
+//go:linkname sync_atomic_SwapPointer sync/atomic.SwapPointer
+//go:nosplit
+func sync_atomic_SwapPointer(ptr unsafe.Pointer, new unsafe.Pointer) unsafe.Pointer {
+	old := unsafe.Pointer(sync_atomic_SwapUintptr((*uintptr)(noescape(ptr)), uintptr(new)))
+	writebarrierptr_nostore((*uintptr)(ptr), uintptr(new))
+	if mheap_.shadow_enabled {
+		writebarrierptr_noshadow((*uintptr)(noescape(ptr)))
+	}
+	return old
+}
+
+//go:linkname sync_atomic_CompareAndSwapUintptr sync/atomic.CompareAndSwapUintptr
+func sync_atomic_CompareAndSwapUintptr(ptr *uintptr, old, new uintptr) bool
+
+//go:linkname sync_atomic_CompareAndSwapPointer sync/atomic.CompareAndSwapPointer
+//go:nosplit
+func sync_atomic_CompareAndSwapPointer(ptr *unsafe.Pointer, old, new unsafe.Pointer) bool {
+	if !sync_atomic_CompareAndSwapUintptr((*uintptr)(noescape(unsafe.Pointer(ptr))), uintptr(old), uintptr(new)) {
+		return false
+	}
+	writebarrierptr_nostore((*uintptr)(unsafe.Pointer(ptr)), uintptr(new))
+	if mheap_.shadow_enabled {
+		writebarrierptr_noshadow((*uintptr)(noescape(unsafe.Pointer(ptr))))
+	}
+	return true
+}