1 // Copyright 2009 The Go Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style 3 // license that can be found in the LICENSE file. 4 5 package runtime 6 7 import "unsafe" 8 9 // These functions cannot have go:noescape annotations, 10 // because while ptr does not escape, new does. 11 // If new is marked as not escaping, the compiler will make incorrect 12 // escape analysis decisions about the pointer value being stored. 13 // Instead, these are wrappers around the actual atomics (xchgp1 and so on) 14 // that use noescape to convey which arguments do not escape. 15 // 16 // Additionally, these functions must update the shadow heap for 17 // write barrier checking. 18 19 //go:nosplit 20 func atomicstorep(ptr unsafe.Pointer, new unsafe.Pointer) { 21 atomicstorep1(noescape(ptr), new) 22 writebarrierptr_nostore((*uintptr)(ptr), uintptr(new)) 23 } 24 25 //go:nosplit 26 func xchgp(ptr unsafe.Pointer, new unsafe.Pointer) unsafe.Pointer { 27 old := xchgp1(noescape(ptr), new) 28 writebarrierptr_nostore((*uintptr)(ptr), uintptr(new)) 29 return old 30 } 31 32 //go:nosplit 33 func casp(ptr *unsafe.Pointer, old, new unsafe.Pointer) bool { 34 if !casp1((*unsafe.Pointer)(noescape(unsafe.Pointer(ptr))), noescape(old), new) { 35 return false 36 } 37 writebarrierptr_nostore((*uintptr)(unsafe.Pointer(ptr)), uintptr(new)) 38 return true 39 } 40 41 // Like above, but implement in terms of sync/atomic's uintptr operations. 42 // We cannot just call the runtime routines, because the race detector expects 43 // to be able to intercept the sync/atomic forms but not the runtime forms. 44 45 //go:linkname sync_atomic_StoreUintptr sync/atomic.StoreUintptr 46 func sync_atomic_StoreUintptr(ptr *uintptr, new uintptr) 47 48 //go:linkname sync_atomic_StorePointer sync/atomic.StorePointer 49 //go:nosplit 50 func sync_atomic_StorePointer(ptr *unsafe.Pointer, new unsafe.Pointer) { 51 sync_atomic_StoreUintptr((*uintptr)(unsafe.Pointer(ptr)), uintptr(new)) 52 atomicstorep1(noescape(unsafe.Pointer(ptr)), new) 53 writebarrierptr_nostore((*uintptr)(unsafe.Pointer(ptr)), uintptr(new)) 54 } 55 56 //go:linkname sync_atomic_SwapUintptr sync/atomic.SwapUintptr 57 func sync_atomic_SwapUintptr(ptr *uintptr, new uintptr) uintptr 58 59 //go:linkname sync_atomic_SwapPointer sync/atomic.SwapPointer 60 //go:nosplit 61 func sync_atomic_SwapPointer(ptr unsafe.Pointer, new unsafe.Pointer) unsafe.Pointer { 62 old := unsafe.Pointer(sync_atomic_SwapUintptr((*uintptr)(noescape(ptr)), uintptr(new))) 63 writebarrierptr_nostore((*uintptr)(ptr), uintptr(new)) 64 return old 65 } 66 67 //go:linkname sync_atomic_CompareAndSwapUintptr sync/atomic.CompareAndSwapUintptr 68 func sync_atomic_CompareAndSwapUintptr(ptr *uintptr, old, new uintptr) bool 69 70 //go:linkname sync_atomic_CompareAndSwapPointer sync/atomic.CompareAndSwapPointer 71 //go:nosplit 72 func sync_atomic_CompareAndSwapPointer(ptr *unsafe.Pointer, old, new unsafe.Pointer) bool { 73 if !sync_atomic_CompareAndSwapUintptr((*uintptr)(noescape(unsafe.Pointer(ptr))), uintptr(old), uintptr(new)) { 74 return false 75 } 76 writebarrierptr_nostore((*uintptr)(unsafe.Pointer(ptr)), uintptr(new)) 77 return true 78 } 79
