+++ /dev/null
-// Copyright 2016 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.
-
-// Binary package export.
-// This file was derived from $GOROOT/src/cmd/compile/internal/gc/bexport.go;
-// see that file for specification of the format.
-
-package gcimporter
-
-import (
- "bytes"
- "encoding/binary"
- "fmt"
- "go/ast"
- "go/constant"
- "go/token"
- "go/types"
- "math"
- "math/big"
- "sort"
- "strings"
-)
-
-// If debugFormat is set, each integer and string value is preceded by a marker
-// and position information in the encoding. This mechanism permits an importer
-// to recognize immediately when it is out of sync. The importer recognizes this
-// mode automatically (i.e., it can import export data produced with debugging
-// support even if debugFormat is not set at the time of import). This mode will
-// lead to massively larger export data (by a factor of 2 to 3) and should only
-// be enabled during development and debugging.
-//
-// NOTE: This flag is the first flag to enable if importing dies because of
-// (suspected) format errors, and whenever a change is made to the format.
-const debugFormat = false // default: false
-
-// If trace is set, debugging output is printed to std out.
-const trace = false // default: false
-
-// Current export format version. Increase with each format change.
-// Note: The latest binary (non-indexed) export format is at version 6.
-// This exporter is still at level 4, but it doesn't matter since
-// the binary importer can handle older versions just fine.
-// 6: package height (CL 105038) -- NOT IMPLEMENTED HERE
-// 5: improved position encoding efficiency (issue 20080, CL 41619) -- NOT IMPLEMEMTED HERE
-// 4: type name objects support type aliases, uses aliasTag
-// 3: Go1.8 encoding (same as version 2, aliasTag defined but never used)
-// 2: removed unused bool in ODCL export (compiler only)
-// 1: header format change (more regular), export package for _ struct fields
-// 0: Go1.7 encoding
-const exportVersion = 4
-
-// trackAllTypes enables cycle tracking for all types, not just named
-// types. The existing compiler invariants assume that unnamed types
-// that are not completely set up are not used, or else there are spurious
-// errors.
-// If disabled, only named types are tracked, possibly leading to slightly
-// less efficient encoding in rare cases. It also prevents the export of
-// some corner-case type declarations (but those are not handled correctly
-// with with the textual export format either).
-// TODO(gri) enable and remove once issues caused by it are fixed
-const trackAllTypes = false
-
-type exporter struct {
- fset *token.FileSet
- out bytes.Buffer
-
- // object -> index maps, indexed in order of serialization
- strIndex map[string]int
- pkgIndex map[*types.Package]int
- typIndex map[types.Type]int
-
- // position encoding
- posInfoFormat bool
- prevFile string
- prevLine int
-
- // debugging support
- written int // bytes written
- indent int // for trace
-}
-
-// internalError represents an error generated inside this package.
-type internalError string
-
-func (e internalError) Error() string { return "gcimporter: " + string(e) }
-
-func internalErrorf(format string, args ...interface{}) error {
- return internalError(fmt.Sprintf(format, args...))
-}
-
-// BExportData returns binary export data for pkg.
-// If no file set is provided, position info will be missing.
-func BExportData(fset *token.FileSet, pkg *types.Package) (b []byte, err error) {
- defer func() {
- if e := recover(); e != nil {
- if ierr, ok := e.(internalError); ok {
- err = ierr
- return
- }
- // Not an internal error; panic again.
- panic(e)
- }
- }()
-
- p := exporter{
- fset: fset,
- strIndex: map[string]int{"": 0}, // empty string is mapped to 0
- pkgIndex: make(map[*types.Package]int),
- typIndex: make(map[types.Type]int),
- posInfoFormat: true, // TODO(gri) might become a flag, eventually
- }
-
- // write version info
- // The version string must start with "version %d" where %d is the version
- // number. Additional debugging information may follow after a blank; that
- // text is ignored by the importer.
- p.rawStringln(fmt.Sprintf("version %d", exportVersion))
- var debug string
- if debugFormat {
- debug = "debug"
- }
- p.rawStringln(debug) // cannot use p.bool since it's affected by debugFormat; also want to see this clearly
- p.bool(trackAllTypes)
- p.bool(p.posInfoFormat)
-
- // --- generic export data ---
-
- // populate type map with predeclared "known" types
- for index, typ := range predeclared() {
- p.typIndex[typ] = index
- }
- if len(p.typIndex) != len(predeclared()) {
- return nil, internalError("duplicate entries in type map?")
- }
-
- // write package data
- p.pkg(pkg, true)
- if trace {
- p.tracef("\n")
- }
-
- // write objects
- objcount := 0
- scope := pkg.Scope()
- for _, name := range scope.Names() {
- if !ast.IsExported(name) {
- continue
- }
- if trace {
- p.tracef("\n")
- }
- p.obj(scope.Lookup(name))
- objcount++
- }
-
- // indicate end of list
- if trace {
- p.tracef("\n")
- }
- p.tag(endTag)
-
- // for self-verification only (redundant)
- p.int(objcount)
-
- if trace {
- p.tracef("\n")
- }
-
- // --- end of export data ---
-
- return p.out.Bytes(), nil
-}
-
-func (p *exporter) pkg(pkg *types.Package, emptypath bool) {
- if pkg == nil {
- panic(internalError("unexpected nil pkg"))
- }
-
- // if we saw the package before, write its index (>= 0)
- if i, ok := p.pkgIndex[pkg]; ok {
- p.index('P', i)
- return
- }
-
- // otherwise, remember the package, write the package tag (< 0) and package data
- if trace {
- p.tracef("P%d = { ", len(p.pkgIndex))
- defer p.tracef("} ")
- }
- p.pkgIndex[pkg] = len(p.pkgIndex)
-
- p.tag(packageTag)
- p.string(pkg.Name())
- if emptypath {
- p.string("")
- } else {
- p.string(pkg.Path())
- }
-}
-
-func (p *exporter) obj(obj types.Object) {
- switch obj := obj.(type) {
- case *types.Const:
- p.tag(constTag)
- p.pos(obj)
- p.qualifiedName(obj)
- p.typ(obj.Type())
- p.value(obj.Val())
-
- case *types.TypeName:
- if obj.IsAlias() {
- p.tag(aliasTag)
- p.pos(obj)
- p.qualifiedName(obj)
- } else {
- p.tag(typeTag)
- }
- p.typ(obj.Type())
-
- case *types.Var:
- p.tag(varTag)
- p.pos(obj)
- p.qualifiedName(obj)
- p.typ(obj.Type())
-
- case *types.Func:
- p.tag(funcTag)
- p.pos(obj)
- p.qualifiedName(obj)
- sig := obj.Type().(*types.Signature)
- p.paramList(sig.Params(), sig.Variadic())
- p.paramList(sig.Results(), false)
-
- default:
- panic(internalErrorf("unexpected object %v (%T)", obj, obj))
- }
-}
-
-func (p *exporter) pos(obj types.Object) {
- if !p.posInfoFormat {
- return
- }
-
- file, line := p.fileLine(obj)
- if file == p.prevFile {
- // common case: write line delta
- // delta == 0 means different file or no line change
- delta := line - p.prevLine
- p.int(delta)
- if delta == 0 {
- p.int(-1) // -1 means no file change
- }
- } else {
- // different file
- p.int(0)
- // Encode filename as length of common prefix with previous
- // filename, followed by (possibly empty) suffix. Filenames
- // frequently share path prefixes, so this can save a lot
- // of space and make export data size less dependent on file
- // path length. The suffix is unlikely to be empty because
- // file names tend to end in ".go".
- n := commonPrefixLen(p.prevFile, file)
- p.int(n) // n >= 0
- p.string(file[n:]) // write suffix only
- p.prevFile = file
- p.int(line)
- }
- p.prevLine = line
-}
-
-func (p *exporter) fileLine(obj types.Object) (file string, line int) {
- if p.fset != nil {
- pos := p.fset.Position(obj.Pos())
- file = pos.Filename
- line = pos.Line
- }
- return
-}
-
-func commonPrefixLen(a, b string) int {
- if len(a) > len(b) {
- a, b = b, a
- }
- // len(a) <= len(b)
- i := 0
- for i < len(a) && a[i] == b[i] {
- i++
- }
- return i
-}
-
-func (p *exporter) qualifiedName(obj types.Object) {
- p.string(obj.Name())
- p.pkg(obj.Pkg(), false)
-}
-
-func (p *exporter) typ(t types.Type) {
- if t == nil {
- panic(internalError("nil type"))
- }
-
- // Possible optimization: Anonymous pointer types *T where
- // T is a named type are common. We could canonicalize all
- // such types *T to a single type PT = *T. This would lead
- // to at most one *T entry in typIndex, and all future *T's
- // would be encoded as the respective index directly. Would
- // save 1 byte (pointerTag) per *T and reduce the typIndex
- // size (at the cost of a canonicalization map). We can do
- // this later, without encoding format change.
-
- // if we saw the type before, write its index (>= 0)
- if i, ok := p.typIndex[t]; ok {
- p.index('T', i)
- return
- }
-
- // otherwise, remember the type, write the type tag (< 0) and type data
- if trackAllTypes {
- if trace {
- p.tracef("T%d = {>\n", len(p.typIndex))
- defer p.tracef("<\n} ")
- }
- p.typIndex[t] = len(p.typIndex)
- }
-
- switch t := t.(type) {
- case *types.Named:
- if !trackAllTypes {
- // if we don't track all types, track named types now
- p.typIndex[t] = len(p.typIndex)
- }
-
- p.tag(namedTag)
- p.pos(t.Obj())
- p.qualifiedName(t.Obj())
- p.typ(t.Underlying())
- if !types.IsInterface(t) {
- p.assocMethods(t)
- }
-
- case *types.Array:
- p.tag(arrayTag)
- p.int64(t.Len())
- p.typ(t.Elem())
-
- case *types.Slice:
- p.tag(sliceTag)
- p.typ(t.Elem())
-
- case *dddSlice:
- p.tag(dddTag)
- p.typ(t.elem)
-
- case *types.Struct:
- p.tag(structTag)
- p.fieldList(t)
-
- case *types.Pointer:
- p.tag(pointerTag)
- p.typ(t.Elem())
-
- case *types.Signature:
- p.tag(signatureTag)
- p.paramList(t.Params(), t.Variadic())
- p.paramList(t.Results(), false)
-
- case *types.Interface:
- p.tag(interfaceTag)
- p.iface(t)
-
- case *types.Map:
- p.tag(mapTag)
- p.typ(t.Key())
- p.typ(t.Elem())
-
- case *types.Chan:
- p.tag(chanTag)
- p.int(int(3 - t.Dir())) // hack
- p.typ(t.Elem())
-
- default:
- panic(internalErrorf("unexpected type %T: %s", t, t))
- }
-}
-
-func (p *exporter) assocMethods(named *types.Named) {
- // Sort methods (for determinism).
- var methods []*types.Func
- for i := 0; i < named.NumMethods(); i++ {
- methods = append(methods, named.Method(i))
- }
- sort.Sort(methodsByName(methods))
-
- p.int(len(methods))
-
- if trace && methods != nil {
- p.tracef("associated methods {>\n")
- }
-
- for i, m := range methods {
- if trace && i > 0 {
- p.tracef("\n")
- }
-
- p.pos(m)
- name := m.Name()
- p.string(name)
- if !exported(name) {
- p.pkg(m.Pkg(), false)
- }
-
- sig := m.Type().(*types.Signature)
- p.paramList(types.NewTuple(sig.Recv()), false)
- p.paramList(sig.Params(), sig.Variadic())
- p.paramList(sig.Results(), false)
- p.int(0) // dummy value for go:nointerface pragma - ignored by importer
- }
-
- if trace && methods != nil {
- p.tracef("<\n} ")
- }
-}
-
-type methodsByName []*types.Func
-
-func (x methodsByName) Len() int { return len(x) }
-func (x methodsByName) Swap(i, j int) { x[i], x[j] = x[j], x[i] }
-func (x methodsByName) Less(i, j int) bool { return x[i].Name() < x[j].Name() }
-
-func (p *exporter) fieldList(t *types.Struct) {
- if trace && t.NumFields() > 0 {
- p.tracef("fields {>\n")
- defer p.tracef("<\n} ")
- }
-
- p.int(t.NumFields())
- for i := 0; i < t.NumFields(); i++ {
- if trace && i > 0 {
- p.tracef("\n")
- }
- p.field(t.Field(i))
- p.string(t.Tag(i))
- }
-}
-
-func (p *exporter) field(f *types.Var) {
- if !f.IsField() {
- panic(internalError("field expected"))
- }
-
- p.pos(f)
- p.fieldName(f)
- p.typ(f.Type())
-}
-
-func (p *exporter) iface(t *types.Interface) {
- // TODO(gri): enable importer to load embedded interfaces,
- // then emit Embeddeds and ExplicitMethods separately here.
- p.int(0)
-
- n := t.NumMethods()
- if trace && n > 0 {
- p.tracef("methods {>\n")
- defer p.tracef("<\n} ")
- }
- p.int(n)
- for i := 0; i < n; i++ {
- if trace && i > 0 {
- p.tracef("\n")
- }
- p.method(t.Method(i))
- }
-}
-
-func (p *exporter) method(m *types.Func) {
- sig := m.Type().(*types.Signature)
- if sig.Recv() == nil {
- panic(internalError("method expected"))
- }
-
- p.pos(m)
- p.string(m.Name())
- if m.Name() != "_" && !ast.IsExported(m.Name()) {
- p.pkg(m.Pkg(), false)
- }
-
- // interface method; no need to encode receiver.
- p.paramList(sig.Params(), sig.Variadic())
- p.paramList(sig.Results(), false)
-}
-
-func (p *exporter) fieldName(f *types.Var) {
- name := f.Name()
-
- if f.Anonymous() {
- // anonymous field - we distinguish between 3 cases:
- // 1) field name matches base type name and is exported
- // 2) field name matches base type name and is not exported
- // 3) field name doesn't match base type name (alias name)
- bname := basetypeName(f.Type())
- if name == bname {
- if ast.IsExported(name) {
- name = "" // 1) we don't need to know the field name or package
- } else {
- name = "?" // 2) use unexported name "?" to force package export
- }
- } else {
- // 3) indicate alias and export name as is
- // (this requires an extra "@" but this is a rare case)
- p.string("@")
- }
- }
-
- p.string(name)
- if name != "" && !ast.IsExported(name) {
- p.pkg(f.Pkg(), false)
- }
-}
-
-func basetypeName(typ types.Type) string {
- switch typ := deref(typ).(type) {
- case *types.Basic:
- return typ.Name()
- case *types.Named:
- return typ.Obj().Name()
- default:
- return "" // unnamed type
- }
-}
-
-func (p *exporter) paramList(params *types.Tuple, variadic bool) {
- // use negative length to indicate unnamed parameters
- // (look at the first parameter only since either all
- // names are present or all are absent)
- n := params.Len()
- if n > 0 && params.At(0).Name() == "" {
- n = -n
- }
- p.int(n)
- for i := 0; i < params.Len(); i++ {
- q := params.At(i)
- t := q.Type()
- if variadic && i == params.Len()-1 {
- t = &dddSlice{t.(*types.Slice).Elem()}
- }
- p.typ(t)
- if n > 0 {
- name := q.Name()
- p.string(name)
- if name != "_" {
- p.pkg(q.Pkg(), false)
- }
- }
- p.string("") // no compiler-specific info
- }
-}
-
-func (p *exporter) value(x constant.Value) {
- if trace {
- p.tracef("= ")
- }
-
- switch x.Kind() {
- case constant.Bool:
- tag := falseTag
- if constant.BoolVal(x) {
- tag = trueTag
- }
- p.tag(tag)
-
- case constant.Int:
- if v, exact := constant.Int64Val(x); exact {
- // common case: x fits into an int64 - use compact encoding
- p.tag(int64Tag)
- p.int64(v)
- return
- }
- // uncommon case: large x - use float encoding
- // (powers of 2 will be encoded efficiently with exponent)
- p.tag(floatTag)
- p.float(constant.ToFloat(x))
-
- case constant.Float:
- p.tag(floatTag)
- p.float(x)
-
- case constant.Complex:
- p.tag(complexTag)
- p.float(constant.Real(x))
- p.float(constant.Imag(x))
-
- case constant.String:
- p.tag(stringTag)
- p.string(constant.StringVal(x))
-
- case constant.Unknown:
- // package contains type errors
- p.tag(unknownTag)
-
- default:
- panic(internalErrorf("unexpected value %v (%T)", x, x))
- }
-}
-
-func (p *exporter) float(x constant.Value) {
- if x.Kind() != constant.Float {
- panic(internalErrorf("unexpected constant %v, want float", x))
- }
- // extract sign (there is no -0)
- sign := constant.Sign(x)
- if sign == 0 {
- // x == 0
- p.int(0)
- return
- }
- // x != 0
-
- var f big.Float
- if v, exact := constant.Float64Val(x); exact {
- // float64
- f.SetFloat64(v)
- } else if num, denom := constant.Num(x), constant.Denom(x); num.Kind() == constant.Int {
- // TODO(gri): add big.Rat accessor to constant.Value.
- r := valueToRat(num)
- f.SetRat(r.Quo(r, valueToRat(denom)))
- } else {
- // Value too large to represent as a fraction => inaccessible.
- // TODO(gri): add big.Float accessor to constant.Value.
- f.SetFloat64(math.MaxFloat64) // FIXME
- }
-
- // extract exponent such that 0.5 <= m < 1.0
- var m big.Float
- exp := f.MantExp(&m)
-
- // extract mantissa as *big.Int
- // - set exponent large enough so mant satisfies mant.IsInt()
- // - get *big.Int from mant
- m.SetMantExp(&m, int(m.MinPrec()))
- mant, acc := m.Int(nil)
- if acc != big.Exact {
- panic(internalError("internal error"))
- }
-
- p.int(sign)
- p.int(exp)
- p.string(string(mant.Bytes()))
-}
-
-func valueToRat(x constant.Value) *big.Rat {
- // Convert little-endian to big-endian.
- // I can't believe this is necessary.
- bytes := constant.Bytes(x)
- for i := 0; i < len(bytes)/2; i++ {
- bytes[i], bytes[len(bytes)-1-i] = bytes[len(bytes)-1-i], bytes[i]
- }
- return new(big.Rat).SetInt(new(big.Int).SetBytes(bytes))
-}
-
-func (p *exporter) bool(b bool) bool {
- if trace {
- p.tracef("[")
- defer p.tracef("= %v] ", b)
- }
-
- x := 0
- if b {
- x = 1
- }
- p.int(x)
- return b
-}
-
-// ----------------------------------------------------------------------------
-// Low-level encoders
-
-func (p *exporter) index(marker byte, index int) {
- if index < 0 {
- panic(internalError("invalid index < 0"))
- }
- if debugFormat {
- p.marker('t')
- }
- if trace {
- p.tracef("%c%d ", marker, index)
- }
- p.rawInt64(int64(index))
-}
-
-func (p *exporter) tag(tag int) {
- if tag >= 0 {
- panic(internalError("invalid tag >= 0"))
- }
- if debugFormat {
- p.marker('t')
- }
- if trace {
- p.tracef("%s ", tagString[-tag])
- }
- p.rawInt64(int64(tag))
-}
-
-func (p *exporter) int(x int) {
- p.int64(int64(x))
-}
-
-func (p *exporter) int64(x int64) {
- if debugFormat {
- p.marker('i')
- }
- if trace {
- p.tracef("%d ", x)
- }
- p.rawInt64(x)
-}
-
-func (p *exporter) string(s string) {
- if debugFormat {
- p.marker('s')
- }
- if trace {
- p.tracef("%q ", s)
- }
- // if we saw the string before, write its index (>= 0)
- // (the empty string is mapped to 0)
- if i, ok := p.strIndex[s]; ok {
- p.rawInt64(int64(i))
- return
- }
- // otherwise, remember string and write its negative length and bytes
- p.strIndex[s] = len(p.strIndex)
- p.rawInt64(-int64(len(s)))
- for i := 0; i < len(s); i++ {
- p.rawByte(s[i])
- }
-}
-
-// marker emits a marker byte and position information which makes
-// it easy for a reader to detect if it is "out of sync". Used for
-// debugFormat format only.
-func (p *exporter) marker(m byte) {
- p.rawByte(m)
- // Enable this for help tracking down the location
- // of an incorrect marker when running in debugFormat.
- if false && trace {
- p.tracef("#%d ", p.written)
- }
- p.rawInt64(int64(p.written))
-}
-
-// rawInt64 should only be used by low-level encoders.
-func (p *exporter) rawInt64(x int64) {
- var tmp [binary.MaxVarintLen64]byte
- n := binary.PutVarint(tmp[:], x)
- for i := 0; i < n; i++ {
- p.rawByte(tmp[i])
- }
-}
-
-// rawStringln should only be used to emit the initial version string.
-func (p *exporter) rawStringln(s string) {
- for i := 0; i < len(s); i++ {
- p.rawByte(s[i])
- }
- p.rawByte('\n')
-}
-
-// rawByte is the bottleneck interface to write to p.out.
-// rawByte escapes b as follows (any encoding does that
-// hides '$'):
-//
-// '$' => '|' 'S'
-// '|' => '|' '|'
-//
-// Necessary so other tools can find the end of the
-// export data by searching for "$$".
-// rawByte should only be used by low-level encoders.
-func (p *exporter) rawByte(b byte) {
- switch b {
- case '$':
- // write '$' as '|' 'S'
- b = 'S'
- fallthrough
- case '|':
- // write '|' as '|' '|'
- p.out.WriteByte('|')
- p.written++
- }
- p.out.WriteByte(b)
- p.written++
-}
-
-// tracef is like fmt.Printf but it rewrites the format string
-// to take care of indentation.
-func (p *exporter) tracef(format string, args ...interface{}) {
- if strings.ContainsAny(format, "<>\n") {
- var buf bytes.Buffer
- for i := 0; i < len(format); i++ {
- // no need to deal with runes
- ch := format[i]
- switch ch {
- case '>':
- p.indent++
- continue
- case '<':
- p.indent--
- continue
- }
- buf.WriteByte(ch)
- if ch == '\n' {
- for j := p.indent; j > 0; j-- {
- buf.WriteString(". ")
- }
- }
- }
- format = buf.String()
- }
- fmt.Printf(format, args...)
-}
-
-// Debugging support.
-// (tagString is only used when tracing is enabled)
-var tagString = [...]string{
- // Packages
- -packageTag: "package",
-
- // Types
- -namedTag: "named type",
- -arrayTag: "array",
- -sliceTag: "slice",
- -dddTag: "ddd",
- -structTag: "struct",
- -pointerTag: "pointer",
- -signatureTag: "signature",
- -interfaceTag: "interface",
- -mapTag: "map",
- -chanTag: "chan",
-
- // Values
- -falseTag: "false",
- -trueTag: "true",
- -int64Tag: "int64",
- -floatTag: "float",
- -fractionTag: "fraction",
- -complexTag: "complex",
- -stringTag: "string",
- -unknownTag: "unknown",
-
- // Type aliases
- -aliasTag: "alias",
-}
projects / dotfiles / .git / blobdiff