remove memclr/memmove entirely now that they are unused

This breaks with newer Go versions AFAICT, so it’s easier to just remove it entirely.

internal/buffer/out_message_test.go

@@ -49,47 +49,6 @@ func findNonZero(p unsafe.Pointer, n int) int {
 	return n
 }
 
-func TestMemclr(t *testing.T) {
-	// All sizes up to 32 bytes.
-	var sizes []int
-	for i := 0; i <= 32; i++ {
-		sizes = append(sizes, i)
-	}
-
-	// And a few hand-chosen sizes.
-	sizes = append(sizes, []int{
-		39, 41, 64, 127, 128, 129,
-		1<<20 - 1,
-		1 << 20,
-		1<<20 + 1,
-	}...)
-
-	// For each size, fill a buffer with random bytes and then zero it.
-	for _, size := range sizes {
-		size := size
-		t.Run(fmt.Sprintf("size=%d", size), func(t *testing.T) {
-			// Generate
-			b, err := randBytes(size)
-			if err != nil {
-				t.Fatalf("randBytes: %v", err)
-			}
-
-			// Clear
-			var p unsafe.Pointer
-			if len(b) != 0 {
-				p = unsafe.Pointer(&b[0])
-			}
-
-			jacobsa_fuse_memclr(p, uintptr(len(b)))
-
-			// Check
-			if i := findNonZero(p, len(b)); i != len(b) {
-				t.Fatalf("non-zero byte at offset %d", i)
-			}
-		})
-	}
-}
-
 func TestOutMessageAppend(t *testing.T) {
 	var om OutMessage
 	om.Reset()
@@ -234,7 +193,7 @@ func TestOutMessageReset(t *testing.T) {
 		}
 
 		// Ensure a non-zero payload length.
-		p := om.Grow(128)
+		om.Grow(128)
 
 		// Reset.
 		om.Reset()

internal/buffer/runtime.go

@@ -1,31 +0,0 @@
-// Copyright 2015 Google Inc. All Rights Reserved.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package buffer
-
-import "unsafe"
-
-//go:noescape
-
-// Zero the n bytes starting at p.
-//
-// REQUIRES: the region does not contain any Go pointers.
-//go:linkname jacobsa_fuse_memclr runtime.memclrNoHeapPointers
-func jacobsa_fuse_memclr(p unsafe.Pointer, n uintptr)
-
-//go:noescape
-
-// Copy from src to dst, allowing overlap.
-//go:linkname jacobsa_fuse_memmove runtime.memmove
-func jacobsa_fuse_memmove(dst unsafe.Pointer, src unsafe.Pointer, n uintptr)

internal/buffer/runtimestub.s

@@ -1,18 +0,0 @@
-// Copyright 2015 Google Inc. All Rights Reserved.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-// The buffer package uses //go:linkname to push a few functions into this
-// package but we still need a .s file so the Go tool does not pass -complete
-// to the go tool compile so the latter does not complain about Go functions
-// with no bodies.