From 6ebc31f9fb0ade22c605c146f651f18f9fc0b61d Mon Sep 17 00:00:00 2001 From: Ian Lance Taylor Date: Mon, 12 Feb 2018 11:22:00 -0800 Subject: [PATCH] runtime: remove unused function casp Change-Id: I7c9c83ba236e1050e04377a7591fef7174df698b Reviewed-on: https://go-review.googlesource.com/130415 Run-TryBot: Ian Lance Taylor TryBot-Result: Gobot Gobot Reviewed-by: Brad Fitzpatrick --- src/runtime/atomic_pointer.go | 13 ------------- src/runtime/proc.go | 2 +- src/runtime/runtime1.go | 17 +---------------- 3 files changed, 2 insertions(+), 30 deletions(-) diff --git a/src/runtime/atomic_pointer.go b/src/runtime/atomic_pointer.go index 09cfbda9b1..b8f0c22c63 100644 --- a/src/runtime/atomic_pointer.go +++ b/src/runtime/atomic_pointer.go @@ -13,8 +13,6 @@ import ( // 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 (casp1 and so on) -// that use noescape to convey which arguments do not escape. // atomicwb performs a write barrier before an atomic pointer write. // The caller should guard the call with "if writeBarrier.enabled". @@ -37,17 +35,6 @@ func atomicstorep(ptr unsafe.Pointer, new unsafe.Pointer) { atomic.StorepNoWB(noescape(ptr), new) } -//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. - if writeBarrier.enabled { - atomicwb(ptr, new) - } - return atomic.Casp1((*unsafe.Pointer)(noescape(unsafe.Pointer(ptr))), noescape(old), new) -} - // 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. diff --git a/src/runtime/proc.go b/src/runtime/proc.go index 32467715c4..c9cc7544b8 100644 --- a/src/runtime/proc.go +++ b/src/runtime/proc.go @@ -1599,7 +1599,7 @@ func allocm(_p_ *p, fn func()) *m { // the following strategy: there is a stack of available m's // that can be stolen. Using compare-and-swap // to pop from the stack has ABA races, so we simulate -// a lock by doing an exchange (via casp) to steal the stack +// a lock by doing an exchange (via Casuintptr) to steal the stack // head and replace the top pointer with MLOCKED (1). // This serves as a simple spin lock that we can use even // without an m. The thread that locks the stack in this way diff --git a/src/runtime/runtime1.go b/src/runtime/runtime1.go index a0769bbb67..d5f78baded 100644 --- a/src/runtime/runtime1.go +++ b/src/runtime/runtime1.go @@ -145,7 +145,7 @@ func check() { h uint64 i, i1 float32 j, j1 float64 - k, k1 unsafe.Pointer + k unsafe.Pointer l *uint16 m [4]byte ) @@ -234,21 +234,6 @@ func check() { throw("cas6") } - k = unsafe.Pointer(uintptr(0xfedcb123)) - if sys.PtrSize == 8 { - k = unsafe.Pointer(uintptr(k) << 10) - } - if casp(&k, nil, nil) { - throw("casp1") - } - k1 = add(k, 1) - if !casp(&k, k, k1) { - throw("casp2") - } - if k != k1 { - throw("casp3") - } - m = [4]byte{1, 1, 1, 1} atomic.Or8(&m[1], 0xf0) if m[0] != 1 || m[1] != 0xf1 || m[2] != 1 || m[3] != 1 { -- 2.48.1