From 387501219e87701a6adeb8417542927ee39b9950 Mon Sep 17 00:00:00 2001
From: Rahat Mahmood <rahat@google.com>
Date: Tue, 29 Sep 2020 18:06:19 -0700
Subject: Replace remaining uses of reflection-based marshalling.

- Rewrite arch.Stack.{Push,Pop}. For the most part, stack now
  implements marshal.CopyContext and can be used as the target of
  marshal operations. Stack.Push had some extra logic for
  automatically null-terminating slices. This was only used for two
  specific types of slices, and is now handled explicitly.

- Delete usermem.CopyObject{In,Out}.

- Replace most remaining uses of the encoding/binary package with
  go-marshal. Most of these were using the binary package to compute
  the size of a struct, which go-marshal can directly replace. ~3 uses
  of the binary package remain. These aren't reasonably replaceable by
  go-marshal: for example one use is to construct the syscall
  trampoline for systrap.

- Fill out remaining convenience wrappers in the primitive package.

PiperOrigin-RevId: 334502375
---
 pkg/usermem/usermem.go      | 46 ---------------------------------------------
 pkg/usermem/usermem_test.go | 18 ------------------
 2 files changed, 64 deletions(-)

(limited to 'pkg/usermem')

diff --git a/pkg/usermem/usermem.go b/pkg/usermem/usermem.go
index 27279b409..9b1e7a085 100644
--- a/pkg/usermem/usermem.go
+++ b/pkg/usermem/usermem.go
@@ -21,7 +21,6 @@ import (
 	"io"
 	"strconv"
 
-	"gvisor.dev/gvisor/pkg/binary"
 	"gvisor.dev/gvisor/pkg/context"
 	"gvisor.dev/gvisor/pkg/gohacks"
 	"gvisor.dev/gvisor/pkg/safemem"
@@ -184,51 +183,6 @@ func (rw *IOReadWriter) Write(src []byte) (int, error) {
 	return n, err
 }
 
-// CopyObjectOut copies a fixed-size value or slice of fixed-size values from
-// src to the memory mapped at addr in uio. It returns the number of bytes
-// copied.
-//
-// CopyObjectOut must use reflection to encode src; performance-sensitive
-// clients should do encoding manually and use uio.CopyOut directly.
-//
-// Preconditions: Same as IO.CopyOut.
-func CopyObjectOut(ctx context.Context, uio IO, addr Addr, src interface{}, opts IOOpts) (int, error) {
-	w := &IOReadWriter{
-		Ctx:  ctx,
-		IO:   uio,
-		Addr: addr,
-		Opts: opts,
-	}
-	// Allocate a byte slice the size of the object being marshaled. This
-	// adds an extra reflection call, but avoids needing to grow the slice
-	// during encoding, which can result in many heap-allocated slices.
-	b := make([]byte, 0, binary.Size(src))
-	return w.Write(binary.Marshal(b, ByteOrder, src))
-}
-
-// CopyObjectIn copies a fixed-size value or slice of fixed-size values from
-// the memory mapped at addr in uio to dst. It returns the number of bytes
-// copied.
-//
-// CopyObjectIn must use reflection to decode dst; performance-sensitive
-// clients should use uio.CopyIn directly and do decoding manually.
-//
-// Preconditions: Same as IO.CopyIn.
-func CopyObjectIn(ctx context.Context, uio IO, addr Addr, dst interface{}, opts IOOpts) (int, error) {
-	r := &IOReadWriter{
-		Ctx:  ctx,
-		IO:   uio,
-		Addr: addr,
-		Opts: opts,
-	}
-	buf := make([]byte, binary.Size(dst))
-	if _, err := io.ReadFull(r, buf); err != nil {
-		return 0, err
-	}
-	binary.Unmarshal(buf, ByteOrder, dst)
-	return int(r.Addr - addr), nil
-}
-
 // CopyStringIn tuning parameters, defined outside that function for tests.
 const (
 	copyStringIncrement     = 64
diff --git a/pkg/usermem/usermem_test.go b/pkg/usermem/usermem_test.go
index bf3c5df2b..da60b0cc7 100644
--- a/pkg/usermem/usermem_test.go
+++ b/pkg/usermem/usermem_test.go
@@ -16,7 +16,6 @@ package usermem
 
 import (
 	"bytes"
-	"encoding/binary"
 	"fmt"
 	"reflect"
 	"strings"
@@ -174,23 +173,6 @@ type testStruct struct {
 	Uint64 uint64
 }
 
-func TestCopyObject(t *testing.T) {
-	wantObj := testStruct{1, 2, 3, 4, 5, 6, 7, 8}
-	wantN := binary.Size(wantObj)
-	b := &BytesIO{make([]byte, wantN)}
-	ctx := newContext()
-	if n, err := CopyObjectOut(ctx, b, 0, &wantObj, IOOpts{}); n != wantN || err != nil {
-		t.Fatalf("CopyObjectOut: got (%v, %v), wanted (%v, nil)", n, err, wantN)
-	}
-	var gotObj testStruct
-	if n, err := CopyObjectIn(ctx, b, 0, &gotObj, IOOpts{}); n != wantN || err != nil {
-		t.Errorf("CopyObjectIn: got (%v, %v), wanted (%v, nil)", n, err, wantN)
-	}
-	if gotObj != wantObj {
-		t.Errorf("CopyObject round trip: got %+v, wanted %+v", gotObj, wantObj)
-	}
-}
-
 func TestCopyStringInShort(t *testing.T) {
 	// Tests for string length <= copyStringIncrement.
 	want := strings.Repeat("A", copyStringIncrement-2)
-- 
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