[dev.garbage] all: merge dev.cc into dev.garbage

The garbage collector is now written in Go.
There is plenty to clean up (just like on dev.cc).

all.bash passes on darwin/amd64, darwin/386, linux/amd64, linux/386.

TBR=rlh
R=austin, rlh, bradfitz
CC=golang-codereviews
https://codereview.appspot.com/173250043

1 files changed, 91 insertions, 0 deletions

diff --git a/src/runtime/atomic_386.go b/src/runtime/atomic_386.go
new file mode 100644
index 000000000..5563432ef
--- /dev/null
+++ b/src/runtime/atomic_386.go
@@ -0,0 +1,91 @@
+// 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"
+
+// The calls to nop are to keep these functions from being inlined.
+// If they are inlined we have no guarantee that later rewrites of the
+// code by optimizers will preserve the relative order of memory accesses.
+
+//go:nosplit
+func atomicload(ptr *uint32) uint32 {
+	nop()
+	return *ptr
+}
+
+//go:nosplit
+func atomicloadp(ptr unsafe.Pointer) unsafe.Pointer {
+	nop()
+	return *(*unsafe.Pointer)(ptr)
+}
+
+//go:nosplit
+func xadd64(ptr *uint64, delta int64) uint64 {
+	for {
+		old := *ptr
+		if cas64(ptr, old, old+uint64(delta)) {
+			return old + uint64(delta)
+		}
+	}
+}
+
+//go:nosplit
+func xchg64(ptr *uint64, new uint64) uint64 {
+	for {
+		old := *ptr
+		if cas64(ptr, old, new) {
+			return old
+		}
+	}
+}
+
+//go:noescape
+func xadd(ptr *uint32, delta int32) uint32
+
+//go:noescape
+func xchg(ptr *uint32, new uint32) uint32
+
+// xchgp cannot have a go:noescape annotation, 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 value being xchg'ed.
+// Instead, make xchgp a wrapper around the actual atomic.
+// When calling the wrapper we mark ptr as noescape explicitly.
+
+//go:nosplit
+func xchgp(ptr unsafe.Pointer, new unsafe.Pointer) unsafe.Pointer {
+	return xchgp1(noescape(ptr), new)
+}
+
+func xchgp1(ptr unsafe.Pointer, new unsafe.Pointer) unsafe.Pointer
+
+//go:noescape
+func xchguintptr(ptr *uintptr, new uintptr) uintptr
+
+//go:noescape
+func atomicload64(ptr *uint64) uint64
+
+//go:noescape
+func atomicor8(ptr *uint8, val uint8)
+
+//go:noescape
+func cas64(ptr *uint64, old, new uint64) bool
+
+//go:noescape
+func atomicstore(ptr *uint32, val uint32)
+
+//go:noescape
+func atomicstore64(ptr *uint64, val uint64)
+
+// atomicstorep cannot have a go:noescape annotation.
+// See comment above for xchgp.
+
+//go:nosplit
+func atomicstorep(ptr unsafe.Pointer, new unsafe.Pointer) {
+	atomicstorep1(noescape(ptr), new)
+}
+
+func atomicstorep1(ptr unsafe.Pointer, val unsafe.Pointer)