diff options
Diffstat (limited to 'vendor/golang.org/x/tools/go/internal/gcimporter/iexport.go')
-rw-r--r-- | vendor/golang.org/x/tools/go/internal/gcimporter/iexport.go | 739 |
1 files changed, 739 insertions, 0 deletions
diff --git a/vendor/golang.org/x/tools/go/internal/gcimporter/iexport.go b/vendor/golang.org/x/tools/go/internal/gcimporter/iexport.go new file mode 100644 index 0000000..4be32a2 --- /dev/null +++ b/vendor/golang.org/x/tools/go/internal/gcimporter/iexport.go @@ -0,0 +1,739 @@ +// 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 +} |