--- /dev/null
+// Copyright 2019 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.
+
+// Indexed binary package export.
+// This file was derived from $GOROOT/src/cmd/compile/internal/gc/iexport.go;
+// see that file for specification of the format.
+
+package gcimporter
+
+import (
+ "bytes"
+ "encoding/binary"
+ "go/ast"
+ "go/constant"
+ "go/token"
+ "go/types"
+ "io"
+ "math/big"
+ "reflect"
+ "sort"
+)
+
+// Current indexed export format version. Increase with each format change.
+// 0: Go1.11 encoding
+const iexportVersion = 0
+
+// IExportData returns the binary export data for pkg.
+//
+// If no file set is provided, position info will be missing.
+// The package path of the top-level package will not be recorded,
+// so that calls to IImportData can override with a provided package path.
+func IExportData(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 := iexporter{
+ out: bytes.NewBuffer(nil),
+ fset: fset,
+ allPkgs: map[*types.Package]bool{},
+ stringIndex: map[string]uint64{},
+ declIndex: map[types.Object]uint64{},
+ typIndex: map[types.Type]uint64{},
+ localpkg: pkg,
+ }
+
+ for i, pt := range predeclared() {
+ p.typIndex[pt] = uint64(i)
+ }
+ if len(p.typIndex) > predeclReserved {
+ panic(internalErrorf("too many predeclared types: %d > %d", len(p.typIndex), predeclReserved))
+ }
+
+ // Initialize work queue with exported declarations.
+ scope := pkg.Scope()
+ for _, name := range scope.Names() {
+ if ast.IsExported(name) {
+ p.pushDecl(scope.Lookup(name))
+ }
+ }
+
+ // Loop until no more work.
+ for !p.declTodo.empty() {
+ p.doDecl(p.declTodo.popHead())
+ }
+
+ // Append indices to data0 section.
+ dataLen := uint64(p.data0.Len())
+ w := p.newWriter()
+ w.writeIndex(p.declIndex)
+ w.flush()
+
+ // Assemble header.
+ var hdr intWriter
+ hdr.WriteByte('i')
+ hdr.uint64(iexportVersion)
+ hdr.uint64(uint64(p.strings.Len()))
+ hdr.uint64(dataLen)
+
+ // Flush output.
+ io.Copy(p.out, &hdr)
+ io.Copy(p.out, &p.strings)
+ io.Copy(p.out, &p.data0)
+
+ return p.out.Bytes(), nil
+}
+
+// writeIndex writes out an object index. mainIndex indicates whether
+// we're writing out the main index, which is also read by
+// non-compiler tools and includes a complete package description
+// (i.e., name and height).
+func (w *exportWriter) writeIndex(index map[types.Object]uint64) {
+ // Build a map from packages to objects from that package.
+ pkgObjs := map[*types.Package][]types.Object{}
+
+ // For the main index, make sure to include every package that
+ // we reference, even if we're not exporting (or reexporting)
+ // any symbols from it.
+ pkgObjs[w.p.localpkg] = nil
+ for pkg := range w.p.allPkgs {
+ pkgObjs[pkg] = nil
+ }
+
+ for obj := range index {
+ pkgObjs[obj.Pkg()] = append(pkgObjs[obj.Pkg()], obj)
+ }
+
+ var pkgs []*types.Package
+ for pkg, objs := range pkgObjs {
+ pkgs = append(pkgs, pkg)
+
+ sort.Slice(objs, func(i, j int) bool {
+ return objs[i].Name() < objs[j].Name()
+ })
+ }
+
+ sort.Slice(pkgs, func(i, j int) bool {
+ return w.exportPath(pkgs[i]) < w.exportPath(pkgs[j])
+ })
+
+ w.uint64(uint64(len(pkgs)))
+ for _, pkg := range pkgs {
+ w.string(w.exportPath(pkg))
+ w.string(pkg.Name())
+ w.uint64(uint64(0)) // package height is not needed for go/types
+
+ objs := pkgObjs[pkg]
+ w.uint64(uint64(len(objs)))
+ for _, obj := range objs {
+ w.string(obj.Name())
+ w.uint64(index[obj])
+ }
+ }
+}
+
+type iexporter struct {
+ fset *token.FileSet
+ out *bytes.Buffer
+
+ localpkg *types.Package
+
+ // allPkgs tracks all packages that have been referenced by
+ // the export data, so we can ensure to include them in the
+ // main index.
+ allPkgs map[*types.Package]bool
+
+ declTodo objQueue
+
+ strings intWriter
+ stringIndex map[string]uint64
+
+ data0 intWriter
+ declIndex map[types.Object]uint64
+ typIndex map[types.Type]uint64
+}
+
+// stringOff returns the offset of s within the string section.
+// If not already present, it's added to the end.
+func (p *iexporter) stringOff(s string) uint64 {
+ off, ok := p.stringIndex[s]
+ if !ok {
+ off = uint64(p.strings.Len())
+ p.stringIndex[s] = off
+
+ p.strings.uint64(uint64(len(s)))
+ p.strings.WriteString(s)
+ }
+ return off
+}
+
+// pushDecl adds n to the declaration work queue, if not already present.
+func (p *iexporter) pushDecl(obj types.Object) {
+ // Package unsafe is known to the compiler and predeclared.
+ assert(obj.Pkg() != types.Unsafe)
+
+ if _, ok := p.declIndex[obj]; ok {
+ return
+ }
+
+ p.declIndex[obj] = ^uint64(0) // mark n present in work queue
+ p.declTodo.pushTail(obj)
+}
+
+// exportWriter handles writing out individual data section chunks.
+type exportWriter struct {
+ p *iexporter
+
+ data intWriter
+ currPkg *types.Package
+ prevFile string
+ prevLine int64
+}
+
+func (w *exportWriter) exportPath(pkg *types.Package) string {
+ if pkg == w.p.localpkg {
+ return ""
+ }
+ return pkg.Path()
+}
+
+func (p *iexporter) doDecl(obj types.Object) {
+ w := p.newWriter()
+ w.setPkg(obj.Pkg(), false)
+
+ switch obj := obj.(type) {
+ case *types.Var:
+ w.tag('V')
+ w.pos(obj.Pos())
+ w.typ(obj.Type(), obj.Pkg())
+
+ case *types.Func:
+ sig, _ := obj.Type().(*types.Signature)
+ if sig.Recv() != nil {
+ panic(internalErrorf("unexpected method: %v", sig))
+ }
+ w.tag('F')
+ w.pos(obj.Pos())
+ w.signature(sig)
+
+ case *types.Const:
+ w.tag('C')
+ w.pos(obj.Pos())
+ w.value(obj.Type(), obj.Val())
+
+ case *types.TypeName:
+ if obj.IsAlias() {
+ w.tag('A')
+ w.pos(obj.Pos())
+ w.typ(obj.Type(), obj.Pkg())
+ break
+ }
+
+ // Defined type.
+ w.tag('T')
+ w.pos(obj.Pos())
+
+ underlying := obj.Type().Underlying()
+ w.typ(underlying, obj.Pkg())
+
+ t := obj.Type()
+ if types.IsInterface(t) {
+ break
+ }
+
+ named, ok := t.(*types.Named)
+ if !ok {
+ panic(internalErrorf("%s is not a defined type", t))
+ }
+
+ n := named.NumMethods()
+ w.uint64(uint64(n))
+ for i := 0; i < n; i++ {
+ m := named.Method(i)
+ w.pos(m.Pos())
+ w.string(m.Name())
+ sig, _ := m.Type().(*types.Signature)
+ w.param(sig.Recv())
+ w.signature(sig)
+ }
+
+ default:
+ panic(internalErrorf("unexpected object: %v", obj))
+ }
+
+ p.declIndex[obj] = w.flush()
+}
+
+func (w *exportWriter) tag(tag byte) {
+ w.data.WriteByte(tag)
+}
+
+func (w *exportWriter) pos(pos token.Pos) {
+ if w.p.fset == nil {
+ w.int64(0)
+ return
+ }
+
+ p := w.p.fset.Position(pos)
+ file := p.Filename
+ line := int64(p.Line)
+
+ // When file is the same as the last position (common case),
+ // we can save a few bytes by delta encoding just the line
+ // number.
+ //
+ // Note: Because data objects may be read out of order (or not
+ // at all), we can only apply delta encoding within a single
+ // object. This is handled implicitly by tracking prevFile and
+ // prevLine as fields of exportWriter.
+
+ if file == w.prevFile {
+ delta := line - w.prevLine
+ w.int64(delta)
+ if delta == deltaNewFile {
+ w.int64(-1)
+ }
+ } else {
+ w.int64(deltaNewFile)
+ w.int64(line) // line >= 0
+ w.string(file)
+ w.prevFile = file
+ }
+ w.prevLine = line
+}
+
+func (w *exportWriter) pkg(pkg *types.Package) {
+ // Ensure any referenced packages are declared in the main index.
+ w.p.allPkgs[pkg] = true
+
+ w.string(w.exportPath(pkg))
+}
+
+func (w *exportWriter) qualifiedIdent(obj types.Object) {
+ // Ensure any referenced declarations are written out too.
+ w.p.pushDecl(obj)
+
+ w.string(obj.Name())
+ w.pkg(obj.Pkg())
+}
+
+func (w *exportWriter) typ(t types.Type, pkg *types.Package) {
+ w.data.uint64(w.p.typOff(t, pkg))
+}
+
+func (p *iexporter) newWriter() *exportWriter {
+ return &exportWriter{p: p}
+}
+
+func (w *exportWriter) flush() uint64 {
+ off := uint64(w.p.data0.Len())
+ io.Copy(&w.p.data0, &w.data)
+ return off
+}
+
+func (p *iexporter) typOff(t types.Type, pkg *types.Package) uint64 {
+ off, ok := p.typIndex[t]
+ if !ok {
+ w := p.newWriter()
+ w.doTyp(t, pkg)
+ off = predeclReserved + w.flush()
+ p.typIndex[t] = off
+ }
+ return off
+}
+
+func (w *exportWriter) startType(k itag) {
+ w.data.uint64(uint64(k))
+}
+
+func (w *exportWriter) doTyp(t types.Type, pkg *types.Package) {
+ switch t := t.(type) {
+ case *types.Named:
+ w.startType(definedType)
+ w.qualifiedIdent(t.Obj())
+
+ case *types.Pointer:
+ w.startType(pointerType)
+ w.typ(t.Elem(), pkg)
+
+ case *types.Slice:
+ w.startType(sliceType)
+ w.typ(t.Elem(), pkg)
+
+ case *types.Array:
+ w.startType(arrayType)
+ w.uint64(uint64(t.Len()))
+ w.typ(t.Elem(), pkg)
+
+ case *types.Chan:
+ w.startType(chanType)
+ // 1 RecvOnly; 2 SendOnly; 3 SendRecv
+ var dir uint64
+ switch t.Dir() {
+ case types.RecvOnly:
+ dir = 1
+ case types.SendOnly:
+ dir = 2
+ case types.SendRecv:
+ dir = 3
+ }
+ w.uint64(dir)
+ w.typ(t.Elem(), pkg)
+
+ case *types.Map:
+ w.startType(mapType)
+ w.typ(t.Key(), pkg)
+ w.typ(t.Elem(), pkg)
+
+ case *types.Signature:
+ w.startType(signatureType)
+ w.setPkg(pkg, true)
+ w.signature(t)
+
+ case *types.Struct:
+ w.startType(structType)
+ w.setPkg(pkg, true)
+
+ n := t.NumFields()
+ w.uint64(uint64(n))
+ for i := 0; i < n; i++ {
+ f := t.Field(i)
+ w.pos(f.Pos())
+ w.string(f.Name())
+ w.typ(f.Type(), pkg)
+ w.bool(f.Anonymous())
+ w.string(t.Tag(i)) // note (or tag)
+ }
+
+ case *types.Interface:
+ w.startType(interfaceType)
+ w.setPkg(pkg, true)
+
+ n := t.NumEmbeddeds()
+ w.uint64(uint64(n))
+ for i := 0; i < n; i++ {
+ f := t.Embedded(i)
+ w.pos(f.Obj().Pos())
+ w.typ(f.Obj().Type(), f.Obj().Pkg())
+ }
+
+ n = t.NumExplicitMethods()
+ w.uint64(uint64(n))
+ for i := 0; i < n; i++ {
+ m := t.ExplicitMethod(i)
+ w.pos(m.Pos())
+ w.string(m.Name())
+ sig, _ := m.Type().(*types.Signature)
+ w.signature(sig)
+ }
+
+ default:
+ panic(internalErrorf("unexpected type: %v, %v", t, reflect.TypeOf(t)))
+ }
+}
+
+func (w *exportWriter) setPkg(pkg *types.Package, write bool) {
+ if write {
+ w.pkg(pkg)
+ }
+
+ w.currPkg = pkg
+}
+
+func (w *exportWriter) signature(sig *types.Signature) {
+ w.paramList(sig.Params())
+ w.paramList(sig.Results())
+ if sig.Params().Len() > 0 {
+ w.bool(sig.Variadic())
+ }
+}
+
+func (w *exportWriter) paramList(tup *types.Tuple) {
+ n := tup.Len()
+ w.uint64(uint64(n))
+ for i := 0; i < n; i++ {
+ w.param(tup.At(i))
+ }
+}
+
+func (w *exportWriter) param(obj types.Object) {
+ w.pos(obj.Pos())
+ w.localIdent(obj)
+ w.typ(obj.Type(), obj.Pkg())
+}
+
+func (w *exportWriter) value(typ types.Type, v constant.Value) {
+ w.typ(typ, nil)
+
+ switch v.Kind() {
+ case constant.Bool:
+ w.bool(constant.BoolVal(v))
+ case constant.Int:
+ var i big.Int
+ if i64, exact := constant.Int64Val(v); exact {
+ i.SetInt64(i64)
+ } else if ui64, exact := constant.Uint64Val(v); exact {
+ i.SetUint64(ui64)
+ } else {
+ i.SetString(v.ExactString(), 10)
+ }
+ w.mpint(&i, typ)
+ case constant.Float:
+ f := constantToFloat(v)
+ w.mpfloat(f, typ)
+ case constant.Complex:
+ w.mpfloat(constantToFloat(constant.Real(v)), typ)
+ w.mpfloat(constantToFloat(constant.Imag(v)), typ)
+ case constant.String:
+ w.string(constant.StringVal(v))
+ case constant.Unknown:
+ // package contains type errors
+ default:
+ panic(internalErrorf("unexpected value %v (%T)", v, v))
+ }
+}
+
+// constantToFloat converts a constant.Value with kind constant.Float to a
+// big.Float.
+func constantToFloat(x constant.Value) *big.Float {
+ assert(x.Kind() == constant.Float)
+ // Use the same floating-point precision (512) as cmd/compile
+ // (see Mpprec in cmd/compile/internal/gc/mpfloat.go).
+ const mpprec = 512
+ var f big.Float
+ f.SetPrec(mpprec)
+ 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.
+ n := valueToRat(num)
+ d := valueToRat(denom)
+ f.SetRat(n.Quo(n, d))
+ } else {
+ // Value too large to represent as a fraction => inaccessible.
+ // TODO(gri): add big.Float accessor to constant.Value.
+ _, ok := f.SetString(x.ExactString())
+ assert(ok)
+ }
+ return &f
+}
+
+// mpint exports a multi-precision integer.
+//
+// For unsigned types, small values are written out as a single
+// byte. Larger values are written out as a length-prefixed big-endian
+// byte string, where the length prefix is encoded as its complement.
+// For example, bytes 0, 1, and 2 directly represent the integer
+// values 0, 1, and 2; while bytes 255, 254, and 253 indicate a 1-,
+// 2-, and 3-byte big-endian string follow.
+//
+// Encoding for signed types use the same general approach as for
+// unsigned types, except small values use zig-zag encoding and the
+// bottom bit of length prefix byte for large values is reserved as a
+// sign bit.
+//
+// The exact boundary between small and large encodings varies
+// according to the maximum number of bytes needed to encode a value
+// of type typ. As a special case, 8-bit types are always encoded as a
+// single byte.
+//
+// TODO(mdempsky): Is this level of complexity really worthwhile?
+func (w *exportWriter) mpint(x *big.Int, typ types.Type) {
+ basic, ok := typ.Underlying().(*types.Basic)
+ if !ok {
+ panic(internalErrorf("unexpected type %v (%T)", typ.Underlying(), typ.Underlying()))
+ }
+
+ signed, maxBytes := intSize(basic)
+
+ negative := x.Sign() < 0
+ if !signed && negative {
+ panic(internalErrorf("negative unsigned integer; type %v, value %v", typ, x))
+ }
+
+ b := x.Bytes()
+ if len(b) > 0 && b[0] == 0 {
+ panic(internalErrorf("leading zeros"))
+ }
+ if uint(len(b)) > maxBytes {
+ panic(internalErrorf("bad mpint length: %d > %d (type %v, value %v)", len(b), maxBytes, typ, x))
+ }
+
+ maxSmall := 256 - maxBytes
+ if signed {
+ maxSmall = 256 - 2*maxBytes
+ }
+ if maxBytes == 1 {
+ maxSmall = 256
+ }
+
+ // Check if x can use small value encoding.
+ if len(b) <= 1 {
+ var ux uint
+ if len(b) == 1 {
+ ux = uint(b[0])
+ }
+ if signed {
+ ux <<= 1
+ if negative {
+ ux--
+ }
+ }
+ if ux < maxSmall {
+ w.data.WriteByte(byte(ux))
+ return
+ }
+ }
+
+ n := 256 - uint(len(b))
+ if signed {
+ n = 256 - 2*uint(len(b))
+ if negative {
+ n |= 1
+ }
+ }
+ if n < maxSmall || n >= 256 {
+ panic(internalErrorf("encoding mistake: %d, %v, %v => %d", len(b), signed, negative, n))
+ }
+
+ w.data.WriteByte(byte(n))
+ w.data.Write(b)
+}
+
+// mpfloat exports a multi-precision floating point number.
+//
+// The number's value is decomposed into mantissa × 2**exponent, where
+// mantissa is an integer. The value is written out as mantissa (as a
+// multi-precision integer) and then the exponent, except exponent is
+// omitted if mantissa is zero.
+func (w *exportWriter) mpfloat(f *big.Float, typ types.Type) {
+ if f.IsInf() {
+ panic("infinite constant")
+ }
+
+ // Break into f = mant × 2**exp, with 0.5 <= mant < 1.
+ var mant big.Float
+ exp := int64(f.MantExp(&mant))
+
+ // Scale so that mant is an integer.
+ prec := mant.MinPrec()
+ mant.SetMantExp(&mant, int(prec))
+ exp -= int64(prec)
+
+ manti, acc := mant.Int(nil)
+ if acc != big.Exact {
+ panic(internalErrorf("mantissa scaling failed for %f (%s)", f, acc))
+ }
+ w.mpint(manti, typ)
+ if manti.Sign() != 0 {
+ w.int64(exp)
+ }
+}
+
+func (w *exportWriter) bool(b bool) bool {
+ var x uint64
+ if b {
+ x = 1
+ }
+ w.uint64(x)
+ return b
+}
+
+func (w *exportWriter) int64(x int64) { w.data.int64(x) }
+func (w *exportWriter) uint64(x uint64) { w.data.uint64(x) }
+func (w *exportWriter) string(s string) { w.uint64(w.p.stringOff(s)) }
+
+func (w *exportWriter) localIdent(obj types.Object) {
+ // Anonymous parameters.
+ if obj == nil {
+ w.string("")
+ return
+ }
+
+ name := obj.Name()
+ if name == "_" {
+ w.string("_")
+ return
+ }
+
+ w.string(name)
+}
+
+type intWriter struct {
+ bytes.Buffer
+}
+
+func (w *intWriter) int64(x int64) {
+ var buf [binary.MaxVarintLen64]byte
+ n := binary.PutVarint(buf[:], x)
+ w.Write(buf[:n])
+}
+
+func (w *intWriter) uint64(x uint64) {
+ var buf [binary.MaxVarintLen64]byte
+ n := binary.PutUvarint(buf[:], x)
+ w.Write(buf[:n])
+}
+
+func assert(cond bool) {
+ if !cond {
+ panic("internal error: assertion failed")
+ }
+}
+
+// The below is copied from go/src/cmd/compile/internal/gc/syntax.go.
+
+// objQueue is a FIFO queue of types.Object. The zero value of objQueue is
+// a ready-to-use empty queue.
+type objQueue struct {
+ ring []types.Object
+ head, tail int
+}
+
+// empty returns true if q contains no Nodes.
+func (q *objQueue) empty() bool {
+ return q.head == q.tail
+}
+
+// pushTail appends n to the tail of the queue.
+func (q *objQueue) pushTail(obj types.Object) {
+ if len(q.ring) == 0 {
+ q.ring = make([]types.Object, 16)
+ } else if q.head+len(q.ring) == q.tail {
+ // Grow the ring.
+ nring := make([]types.Object, len(q.ring)*2)
+ // Copy the old elements.
+ part := q.ring[q.head%len(q.ring):]
+ if q.tail-q.head <= len(part) {
+ part = part[:q.tail-q.head]
+ copy(nring, part)
+ } else {
+ pos := copy(nring, part)
+ copy(nring[pos:], q.ring[:q.tail%len(q.ring)])
+ }
+ q.ring, q.head, q.tail = nring, 0, q.tail-q.head
+ }
+
+ q.ring[q.tail%len(q.ring)] = obj
+ q.tail++
+}
+
+// popHead pops a node from the head of the queue. It panics if q is empty.
+func (q *objQueue) popHead() types.Object {
+ if q.empty() {
+ panic("dequeue empty")
+ }
+ obj := q.ring[q.head%len(q.ring)]
+ q.head++
+ return obj
+}
projects / dotfiles / .git / blobdiff