blob: 4780f01c392d46f300b534a53f0d17a06e40e572 [file] [log] [blame]
// UNREVIEWED
// Copyright 2021 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 pkgbits
import (
"bytes"
"crypto/md5"
"encoding/binary"
"go/constant"
"io"
"math/big"
"runtime"
)
type PkgEncoder struct {
elems [numRelocs][]string
stringsIdx map[string]int
syncFrames int
}
func NewPkgEncoder(syncFrames int) PkgEncoder {
return PkgEncoder{
stringsIdx: make(map[string]int),
syncFrames: syncFrames,
}
}
func (pw *PkgEncoder) DumpTo(out0 io.Writer) (fingerprint [8]byte) {
h := md5.New()
out := io.MultiWriter(out0, h)
writeUint32 := func(x uint32) {
assert(binary.Write(out, binary.LittleEndian, x) == nil)
}
writeUint32(0) // version
var sum uint32
for _, elems := range &pw.elems {
sum += uint32(len(elems))
writeUint32(sum)
}
sum = 0
for _, elems := range &pw.elems {
for _, elem := range elems {
sum += uint32(len(elem))
writeUint32(sum)
}
}
for _, elems := range &pw.elems {
for _, elem := range elems {
_, err := io.WriteString(out, elem)
assert(err == nil)
}
}
copy(fingerprint[:], h.Sum(nil))
_, err := out0.Write(fingerprint[:])
assert(err == nil)
return
}
func (pw *PkgEncoder) StringIdx(s string) int {
if idx, ok := pw.stringsIdx[s]; ok {
assert(pw.elems[RelocString][idx] == s)
return idx
}
idx := len(pw.elems[RelocString])
pw.elems[RelocString] = append(pw.elems[RelocString], s)
pw.stringsIdx[s] = idx
return idx
}
func (pw *PkgEncoder) NewEncoder(k RelocKind, marker SyncMarker) Encoder {
e := pw.NewEncoderRaw(k)
e.Sync(marker)
return e
}
func (pw *PkgEncoder) NewEncoderRaw(k RelocKind) Encoder {
idx := len(pw.elems[k])
pw.elems[k] = append(pw.elems[k], "") // placeholder
return Encoder{
p: pw,
k: k,
Idx: idx,
}
}
// Encoders
type Encoder struct {
p *PkgEncoder
Relocs []RelocEnt
Data bytes.Buffer
encodingRelocHeader bool
k RelocKind
Idx int
}
func (w *Encoder) Flush() int {
var sb bytes.Buffer // TODO(mdempsky): strings.Builder after #44505 is resolved
// Backup the data so we write the relocations at the front.
var tmp bytes.Buffer
io.Copy(&tmp, &w.Data)
// TODO(mdempsky): Consider writing these out separately so they're
// easier to strip, along with function bodies, so that we can prune
// down to just the data that's relevant to go/types.
if w.encodingRelocHeader {
panic("encodingRelocHeader already true; recursive flush?")
}
w.encodingRelocHeader = true
w.Sync(SyncRelocs)
w.Len(len(w.Relocs))
for _, rent := range w.Relocs {
w.Sync(SyncReloc)
w.Len(int(rent.Kind))
w.Len(rent.Idx)
}
io.Copy(&sb, &w.Data)
io.Copy(&sb, &tmp)
w.p.elems[w.k][w.Idx] = sb.String()
return w.Idx
}
func (w *Encoder) checkErr(err error) {
if err != nil {
errorf("unexpected encoding error: %v", err)
}
}
func (w *Encoder) rawUvarint(x uint64) {
var buf [binary.MaxVarintLen64]byte
n := binary.PutUvarint(buf[:], x)
_, err := w.Data.Write(buf[:n])
w.checkErr(err)
}
func (w *Encoder) rawVarint(x int64) {
// Zig-zag encode.
ux := uint64(x) << 1
if x < 0 {
ux = ^ux
}
w.rawUvarint(ux)
}
func (w *Encoder) rawReloc(r RelocKind, idx int) int {
// TODO(mdempsky): Use map for lookup.
for i, rent := range w.Relocs {
if rent.Kind == r && rent.Idx == idx {
return i
}
}
i := len(w.Relocs)
w.Relocs = append(w.Relocs, RelocEnt{r, idx})
return i
}
func (w *Encoder) Sync(m SyncMarker) {
if !EnableSync {
return
}
// Writing out stack frame string references requires working
// relocations, but writing out the relocations themselves involves
// sync markers. To prevent infinite recursion, we simply trim the
// stack frame for sync markers within the relocation header.
var frames []string
if !w.encodingRelocHeader && w.p.syncFrames > 0 {
pcs := make([]uintptr, w.p.syncFrames)
n := runtime.Callers(2, pcs)
frames = fmtFrames(pcs[:n]...)
}
// TODO(mdempsky): Save space by writing out stack frames as a
// linked list so we can share common stack frames.
w.rawUvarint(uint64(m))
w.rawUvarint(uint64(len(frames)))
for _, frame := range frames {
w.rawUvarint(uint64(w.rawReloc(RelocString, w.p.StringIdx(frame))))
}
}
func (w *Encoder) Bool(b bool) bool {
w.Sync(SyncBool)
var x byte
if b {
x = 1
}
err := w.Data.WriteByte(x)
w.checkErr(err)
return b
}
func (w *Encoder) Int64(x int64) {
w.Sync(SyncInt64)
w.rawVarint(x)
}
func (w *Encoder) Uint64(x uint64) {
w.Sync(SyncUint64)
w.rawUvarint(x)
}
func (w *Encoder) Len(x int) { assert(x >= 0); w.Uint64(uint64(x)) }
func (w *Encoder) Int(x int) { w.Int64(int64(x)) }
func (w *Encoder) Uint(x uint) { w.Uint64(uint64(x)) }
func (w *Encoder) Reloc(r RelocKind, idx int) {
w.Sync(SyncUseReloc)
w.Len(w.rawReloc(r, idx))
}
func (w *Encoder) Code(c Code) {
w.Sync(c.Marker())
w.Len(c.Value())
}
func (w *Encoder) String(s string) {
w.Sync(SyncString)
w.Reloc(RelocString, w.p.StringIdx(s))
}
func (w *Encoder) Strings(ss []string) {
w.Len(len(ss))
for _, s := range ss {
w.String(s)
}
}
func (w *Encoder) Value(val constant.Value) {
w.Sync(SyncValue)
if w.Bool(val.Kind() == constant.Complex) {
w.scalar(constant.Real(val))
w.scalar(constant.Imag(val))
} else {
w.scalar(val)
}
}
func (w *Encoder) scalar(val constant.Value) {
switch v := constant.Val(val).(type) {
default:
errorf("unhandled %v (%v)", val, val.Kind())
case bool:
w.Code(ValBool)
w.Bool(v)
case string:
w.Code(ValString)
w.String(v)
case int64:
w.Code(ValInt64)
w.Int64(v)
case *big.Int:
w.Code(ValBigInt)
w.bigInt(v)
case *big.Rat:
w.Code(ValBigRat)
w.bigInt(v.Num())
w.bigInt(v.Denom())
case *big.Float:
w.Code(ValBigFloat)
w.bigFloat(v)
}
}
func (w *Encoder) bigInt(v *big.Int) {
b := v.Bytes()
w.String(string(b)) // TODO: More efficient encoding.
w.Bool(v.Sign() < 0)
}
func (w *Encoder) bigFloat(v *big.Float) {
b := v.Append(nil, 'p', -1)
w.String(string(b)) // TODO: More efficient encoding.
}