1 files changed, 26 insertions, 17 deletions

diff --git a/vendor/golang.org/x/tools/internal/pkgbits/encoder.go b/vendor/golang.org/x/tools/internal/pkgbits/encoder.go
index 6482617a4..c17a12399 100644
--- a/vendor/golang.org/x/tools/internal/pkgbits/encoder.go
+++ b/vendor/golang.org/x/tools/internal/pkgbits/encoder.go
@@ -12,18 +12,15 @@ import (
 	"io"
 	"math/big"
 	"runtime"
+	"strings"
 )
 
-// currentVersion is the current version number.
-//
-//   - v0: initial prototype
-//
-//   - v1: adds the flags uint32 word
-const currentVersion uint32 = 1
-
 // A PkgEncoder provides methods for encoding a package's Unified IR
 // export data.
 type PkgEncoder struct {
+	// version of the bitstream.
+	version Version
+
 	// elems holds the bitstream for previously encoded elements.
 	elems [numRelocs][]string
 
@@ -47,8 +44,9 @@ func (pw *PkgEncoder) SyncMarkers() bool { return pw.syncFrames >= 0 }
 // export data files, but can help diagnosing desync errors in
 // higher-level Unified IR reader/writer code. If syncFrames is
 // negative, then sync markers are omitted entirely.
-func NewPkgEncoder(syncFrames int) PkgEncoder {
+func NewPkgEncoder(version Version, syncFrames int) PkgEncoder {
 	return PkgEncoder{
+		version:    version,
 		stringsIdx: make(map[string]Index),
 		syncFrames: syncFrames,
 	}
@@ -64,13 +62,15 @@ func (pw *PkgEncoder) DumpTo(out0 io.Writer) (fingerprint [8]byte) {
 		assert(binary.Write(out, binary.LittleEndian, x) == nil)
 	}
 
-	writeUint32(currentVersion)
+	writeUint32(uint32(pw.version))
 
-	var flags uint32
-	if pw.SyncMarkers() {
-		flags |= flagSyncMarkers
+	if pw.version.Has(Flags) {
+		var flags uint32
+		if pw.SyncMarkers() {
+			flags |= flagSyncMarkers
+		}
+		writeUint32(flags)
 	}
-	writeUint32(flags)
 
 	// Write elemEndsEnds.
 	var sum uint32
@@ -159,7 +159,7 @@ type Encoder struct {
 
 // Flush finalizes the element's bitstream and returns its Index.
 func (w *Encoder) Flush() Index {
-	var sb bytes.Buffer // TODO(mdempsky): strings.Builder after #44505 is resolved
+	var sb strings.Builder
 
 	// Backup the data so we write the relocations at the front.
 	var tmp bytes.Buffer
@@ -189,7 +189,7 @@ func (w *Encoder) Flush() Index {
 
 func (w *Encoder) checkErr(err error) {
 	if err != nil {
-		errorf("unexpected encoding error: %v", err)
+		panicf("unexpected encoding error: %v", err)
 	}
 }
 
@@ -320,8 +320,14 @@ func (w *Encoder) Code(c Code) {
 // section (if not already present), and then writing a relocation
 // into the element bitstream.
 func (w *Encoder) String(s string) {
+	w.StringRef(w.p.StringIdx(s))
+}
+
+// StringRef writes a reference to the given index, which must be a
+// previously encoded string value.
+func (w *Encoder) StringRef(idx Index) {
 	w.Sync(SyncString)
-	w.Reloc(RelocString, w.p.StringIdx(s))
+	w.Reloc(RelocString, idx)
 }
 
 // Strings encodes and writes a variable-length slice of strings into
@@ -348,7 +354,7 @@ func (w *Encoder) Value(val constant.Value) {
 func (w *Encoder) scalar(val constant.Value) {
 	switch v := constant.Val(val).(type) {
 	default:
-		errorf("unhandled %v (%v)", val, val.Kind())
+		panicf("unhandled %v (%v)", val, val.Kind())
 	case bool:
 		w.Code(ValBool)
 		w.Bool(v)
@@ -381,3 +387,6 @@ func (w *Encoder) bigFloat(v *big.Float) {
 	b := v.Append(nil, 'p', -1)
 	w.String(string(b)) // TODO: More efficient encoding.
 }
+
+// Version reports the version of the bitstream.
+func (w *Encoder) Version() Version { return w.p.version }