runtime: break atomics out into package runtime/internal/atomic

This change breaks out most of the atomics functions in the runtime
into package runtime/internal/atomic. It adds some basic support
in the toolchain for runtime packages, and also modifies linux/arm
atomics to remove the dependency on the runtime's mutex. The mutexes
have been replaced with spinlocks.

all trybots are happy!
In addition to the trybots, I've tested on the darwin/arm64 builder,
on the darwin/arm builder, and on a ppc64le machine.

Change-Id: I6698c8e3cf3834f55ce5824059f44d00dc8e3c2f
Reviewed-on: https://go-review.googlesource.com/14204
Run-TryBot: Michael Matloob <matloob@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>

1 files changed, 17 insertions, 14 deletions

diff --git a/src/runtime/runtime1.go b/src/runtime/runtime1.go
index 8878817aab..f9b11b4de1 100644
--- a/src/runtime/runtime1.go
+++ b/src/runtime/runtime1.go
@@ -4,7 +4,10 @@
 
 package runtime
 
-import "unsafe"
+import (
+	"runtime/internal/atomic"
+	"unsafe"
+)
 
 // Keep a cached value to make gotraceback fast,
 // since we call it on every call to gentraceback.
@@ -99,36 +102,36 @@ func testAtomic64() {
 	prefetcht1(uintptr(unsafe.Pointer(&test_z64)))
 	prefetcht2(uintptr(unsafe.Pointer(&test_z64)))
 	prefetchnta(uintptr(unsafe.Pointer(&test_z64)))
-	if cas64(&test_z64, test_x64, 1) {
+	if atomic.Cas64(&test_z64, test_x64, 1) {
 		throw("cas64 failed")
 	}
 	if test_x64 != 0 {
 		throw("cas64 failed")
 	}
 	test_x64 = 42
-	if !cas64(&test_z64, test_x64, 1) {
+	if !atomic.Cas64(&test_z64, test_x64, 1) {
 		throw("cas64 failed")
 	}
 	if test_x64 != 42 || test_z64 != 1 {
 		throw("cas64 failed")
 	}
-	if atomicload64(&test_z64) != 1 {
+	if atomic.Load64(&test_z64) != 1 {
 		throw("load64 failed")
 	}
-	atomicstore64(&test_z64, (1<<40)+1)
-	if atomicload64(&test_z64) != (1<<40)+1 {
+	atomic.Store64(&test_z64, (1<<40)+1)
+	if atomic.Load64(&test_z64) != (1<<40)+1 {
 		throw("store64 failed")
 	}
-	if xadd64(&test_z64, (1<<40)+1) != (2<<40)+2 {
+	if atomic.Xadd64(&test_z64, (1<<40)+1) != (2<<40)+2 {
 		throw("xadd64 failed")
 	}
-	if atomicload64(&test_z64) != (2<<40)+2 {
+	if atomic.Load64(&test_z64) != (2<<40)+2 {
 		throw("xadd64 failed")
 	}
-	if xchg64(&test_z64, (3<<40)+3) != (2<<40)+2 {
+	if atomic.Xchg64(&test_z64, (3<<40)+3) != (2<<40)+2 {
 		throw("xchg64 failed")
 	}
-	if atomicload64(&test_z64) != (3<<40)+3 {
+	if atomic.Load64(&test_z64) != (3<<40)+3 {
 		throw("xchg64 failed")
 	}
 }
@@ -211,7 +214,7 @@ func check() {
 
 	var z uint32
 	z = 1
-	if !cas(&z, 1, 2) {
+	if !atomic.Cas(&z, 1, 2) {
 		throw("cas1")
 	}
 	if z != 2 {
@@ -219,7 +222,7 @@ func check() {
 	}
 
 	z = 4
-	if cas(&z, 5, 6) {
+	if atomic.Cas(&z, 5, 6) {
 		throw("cas3")
 	}
 	if z != 4 {
@@ -227,7 +230,7 @@ func check() {
 	}
 
 	z = 0xffffffff
-	if !cas(&z, 0xffffffff, 0xfffffffe) {
+	if !atomic.Cas(&z, 0xffffffff, 0xfffffffe) {
 		throw("cas5")
 	}
 	if z != 0xfffffffe {
@@ -250,7 +253,7 @@ func check() {
 	}
 
 	m = [4]byte{1, 1, 1, 1}
-	atomicor8(&m[1], 0xf0)
+	atomic.Or8(&m[1], 0xf0)
 	if m[0] != 1 || m[1] != 0xf1 || m[2] != 1 || m[3] != 1 {
 		throw("atomicor8")
 	}