--- /dev/null
+// Copyright 2011 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.
+
+// This file is a modified copy of $GOROOT/src/go/internal/gcimporter/gcimporter.go,
+// but it also contains the original source-based importer code for Go1.6.
+// Once we stop supporting 1.6, we can remove that code.
+
+// Package gcimporter provides various functions for reading
+// gc-generated object files that can be used to implement the
+// Importer interface defined by the Go 1.5 standard library package.
+package gcimporter // import "golang.org/x/tools/go/internal/gcimporter"
+
+import (
+ "bufio"
+ "errors"
+ "fmt"
+ "go/build"
+ "go/constant"
+ "go/token"
+ "go/types"
+ "io"
+ "io/ioutil"
+ "os"
+ "path/filepath"
+ "sort"
+ "strconv"
+ "strings"
+ "text/scanner"
+)
+
+// debugging/development support
+const debug = false
+
+var pkgExts = [...]string{".a", ".o"}
+
+// FindPkg returns the filename and unique package id for an import
+// path based on package information provided by build.Import (using
+// the build.Default build.Context). A relative srcDir is interpreted
+// relative to the current working directory.
+// If no file was found, an empty filename is returned.
+//
+func FindPkg(path, srcDir string) (filename, id string) {
+ if path == "" {
+ return
+ }
+
+ var noext string
+ switch {
+ default:
+ // "x" -> "$GOPATH/pkg/$GOOS_$GOARCH/x.ext", "x"
+ // Don't require the source files to be present.
+ if abs, err := filepath.Abs(srcDir); err == nil { // see issue 14282
+ srcDir = abs
+ }
+ bp, _ := build.Import(path, srcDir, build.FindOnly|build.AllowBinary)
+ if bp.PkgObj == "" {
+ id = path // make sure we have an id to print in error message
+ return
+ }
+ noext = strings.TrimSuffix(bp.PkgObj, ".a")
+ id = bp.ImportPath
+
+ case build.IsLocalImport(path):
+ // "./x" -> "/this/directory/x.ext", "/this/directory/x"
+ noext = filepath.Join(srcDir, path)
+ id = noext
+
+ case filepath.IsAbs(path):
+ // for completeness only - go/build.Import
+ // does not support absolute imports
+ // "/x" -> "/x.ext", "/x"
+ noext = path
+ id = path
+ }
+
+ if false { // for debugging
+ if path != id {
+ fmt.Printf("%s -> %s\n", path, id)
+ }
+ }
+
+ // try extensions
+ for _, ext := range pkgExts {
+ filename = noext + ext
+ if f, err := os.Stat(filename); err == nil && !f.IsDir() {
+ return
+ }
+ }
+
+ filename = "" // not found
+ return
+}
+
+// ImportData imports a package by reading the gc-generated export data,
+// adds the corresponding package object to the packages map indexed by id,
+// and returns the object.
+//
+// The packages map must contains all packages already imported. The data
+// reader position must be the beginning of the export data section. The
+// filename is only used in error messages.
+//
+// If packages[id] contains the completely imported package, that package
+// can be used directly, and there is no need to call this function (but
+// there is also no harm but for extra time used).
+//
+func ImportData(packages map[string]*types.Package, filename, id string, data io.Reader) (pkg *types.Package, err error) {
+ // support for parser error handling
+ defer func() {
+ switch r := recover().(type) {
+ case nil:
+ // nothing to do
+ case importError:
+ err = r
+ default:
+ panic(r) // internal error
+ }
+ }()
+
+ var p parser
+ p.init(filename, id, data, packages)
+ pkg = p.parseExport()
+
+ return
+}
+
+// Import imports a gc-generated package given its import path and srcDir, adds
+// the corresponding package object to the packages map, and returns the object.
+// The packages map must contain all packages already imported.
+//
+func Import(packages map[string]*types.Package, path, srcDir string, lookup func(path string) (io.ReadCloser, error)) (pkg *types.Package, err error) {
+ var rc io.ReadCloser
+ var filename, id string
+ if lookup != nil {
+ // With custom lookup specified, assume that caller has
+ // converted path to a canonical import path for use in the map.
+ if path == "unsafe" {
+ return types.Unsafe, nil
+ }
+ id = path
+
+ // No need to re-import if the package was imported completely before.
+ if pkg = packages[id]; pkg != nil && pkg.Complete() {
+ return
+ }
+ f, err := lookup(path)
+ if err != nil {
+ return nil, err
+ }
+ rc = f
+ } else {
+ filename, id = FindPkg(path, srcDir)
+ if filename == "" {
+ if path == "unsafe" {
+ return types.Unsafe, nil
+ }
+ return nil, fmt.Errorf("can't find import: %q", id)
+ }
+
+ // no need to re-import if the package was imported completely before
+ if pkg = packages[id]; pkg != nil && pkg.Complete() {
+ return
+ }
+
+ // open file
+ f, err := os.Open(filename)
+ if err != nil {
+ return nil, err
+ }
+ defer func() {
+ if err != nil {
+ // add file name to error
+ err = fmt.Errorf("%s: %v", filename, err)
+ }
+ }()
+ rc = f
+ }
+ defer rc.Close()
+
+ var hdr string
+ buf := bufio.NewReader(rc)
+ if hdr, err = FindExportData(buf); err != nil {
+ return
+ }
+
+ switch hdr {
+ case "$$\n":
+ // Work-around if we don't have a filename; happens only if lookup != nil.
+ // Either way, the filename is only needed for importer error messages, so
+ // this is fine.
+ if filename == "" {
+ filename = path
+ }
+ return ImportData(packages, filename, id, buf)
+
+ case "$$B\n":
+ var data []byte
+ data, err = ioutil.ReadAll(buf)
+ if err != nil {
+ break
+ }
+
+ // TODO(gri): allow clients of go/importer to provide a FileSet.
+ // Or, define a new standard go/types/gcexportdata package.
+ fset := token.NewFileSet()
+
+ // The indexed export format starts with an 'i'; the older
+ // binary export format starts with a 'c', 'd', or 'v'
+ // (from "version"). Select appropriate importer.
+ if len(data) > 0 && data[0] == 'i' {
+ _, pkg, err = IImportData(fset, packages, data[1:], id)
+ } else {
+ _, pkg, err = BImportData(fset, packages, data, id)
+ }
+
+ default:
+ err = fmt.Errorf("unknown export data header: %q", hdr)
+ }
+
+ return
+}
+
+// ----------------------------------------------------------------------------
+// Parser
+
+// TODO(gri) Imported objects don't have position information.
+// Ideally use the debug table line info; alternatively
+// create some fake position (or the position of the
+// import). That way error messages referring to imported
+// objects can print meaningful information.
+
+// parser parses the exports inside a gc compiler-produced
+// object/archive file and populates its scope with the results.
+type parser struct {
+ scanner scanner.Scanner
+ tok rune // current token
+ lit string // literal string; only valid for Ident, Int, String tokens
+ id string // package id of imported package
+ sharedPkgs map[string]*types.Package // package id -> package object (across importer)
+ localPkgs map[string]*types.Package // package id -> package object (just this package)
+}
+
+func (p *parser) init(filename, id string, src io.Reader, packages map[string]*types.Package) {
+ p.scanner.Init(src)
+ p.scanner.Error = func(_ *scanner.Scanner, msg string) { p.error(msg) }
+ p.scanner.Mode = scanner.ScanIdents | scanner.ScanInts | scanner.ScanChars | scanner.ScanStrings | scanner.ScanComments | scanner.SkipComments
+ p.scanner.Whitespace = 1<<'\t' | 1<<' '
+ p.scanner.Filename = filename // for good error messages
+ p.next()
+ p.id = id
+ p.sharedPkgs = packages
+ if debug {
+ // check consistency of packages map
+ for _, pkg := range packages {
+ if pkg.Name() == "" {
+ fmt.Printf("no package name for %s\n", pkg.Path())
+ }
+ }
+ }
+}
+
+func (p *parser) next() {
+ p.tok = p.scanner.Scan()
+ switch p.tok {
+ case scanner.Ident, scanner.Int, scanner.Char, scanner.String, '·':
+ p.lit = p.scanner.TokenText()
+ default:
+ p.lit = ""
+ }
+ if debug {
+ fmt.Printf("%s: %q -> %q\n", scanner.TokenString(p.tok), p.scanner.TokenText(), p.lit)
+ }
+}
+
+func declTypeName(pkg *types.Package, name string) *types.TypeName {
+ scope := pkg.Scope()
+ if obj := scope.Lookup(name); obj != nil {
+ return obj.(*types.TypeName)
+ }
+ obj := types.NewTypeName(token.NoPos, pkg, name, nil)
+ // a named type may be referred to before the underlying type
+ // is known - set it up
+ types.NewNamed(obj, nil, nil)
+ scope.Insert(obj)
+ return obj
+}
+
+// ----------------------------------------------------------------------------
+// Error handling
+
+// Internal errors are boxed as importErrors.
+type importError struct {
+ pos scanner.Position
+ err error
+}
+
+func (e importError) Error() string {
+ return fmt.Sprintf("import error %s (byte offset = %d): %s", e.pos, e.pos.Offset, e.err)
+}
+
+func (p *parser) error(err interface{}) {
+ if s, ok := err.(string); ok {
+ err = errors.New(s)
+ }
+ // panic with a runtime.Error if err is not an error
+ panic(importError{p.scanner.Pos(), err.(error)})
+}
+
+func (p *parser) errorf(format string, args ...interface{}) {
+ p.error(fmt.Sprintf(format, args...))
+}
+
+func (p *parser) expect(tok rune) string {
+ lit := p.lit
+ if p.tok != tok {
+ p.errorf("expected %s, got %s (%s)", scanner.TokenString(tok), scanner.TokenString(p.tok), lit)
+ }
+ p.next()
+ return lit
+}
+
+func (p *parser) expectSpecial(tok string) {
+ sep := 'x' // not white space
+ i := 0
+ for i < len(tok) && p.tok == rune(tok[i]) && sep > ' ' {
+ sep = p.scanner.Peek() // if sep <= ' ', there is white space before the next token
+ p.next()
+ i++
+ }
+ if i < len(tok) {
+ p.errorf("expected %q, got %q", tok, tok[0:i])
+ }
+}
+
+func (p *parser) expectKeyword(keyword string) {
+ lit := p.expect(scanner.Ident)
+ if lit != keyword {
+ p.errorf("expected keyword %s, got %q", keyword, lit)
+ }
+}
+
+// ----------------------------------------------------------------------------
+// Qualified and unqualified names
+
+// PackageId = string_lit .
+//
+func (p *parser) parsePackageID() string {
+ id, err := strconv.Unquote(p.expect(scanner.String))
+ if err != nil {
+ p.error(err)
+ }
+ // id == "" stands for the imported package id
+ // (only known at time of package installation)
+ if id == "" {
+ id = p.id
+ }
+ return id
+}
+
+// PackageName = ident .
+//
+func (p *parser) parsePackageName() string {
+ return p.expect(scanner.Ident)
+}
+
+// dotIdentifier = ( ident | '·' ) { ident | int | '·' } .
+func (p *parser) parseDotIdent() string {
+ ident := ""
+ if p.tok != scanner.Int {
+ sep := 'x' // not white space
+ for (p.tok == scanner.Ident || p.tok == scanner.Int || p.tok == '·') && sep > ' ' {
+ ident += p.lit
+ sep = p.scanner.Peek() // if sep <= ' ', there is white space before the next token
+ p.next()
+ }
+ }
+ if ident == "" {
+ p.expect(scanner.Ident) // use expect() for error handling
+ }
+ return ident
+}
+
+// QualifiedName = "@" PackageId "." ( "?" | dotIdentifier ) .
+//
+func (p *parser) parseQualifiedName() (id, name string) {
+ p.expect('@')
+ id = p.parsePackageID()
+ p.expect('.')
+ // Per rev f280b8a485fd (10/2/2013), qualified names may be used for anonymous fields.
+ if p.tok == '?' {
+ p.next()
+ } else {
+ name = p.parseDotIdent()
+ }
+ return
+}
+
+// getPkg returns the package for a given id. If the package is
+// not found, create the package and add it to the p.localPkgs
+// and p.sharedPkgs maps. name is the (expected) name of the
+// package. If name == "", the package name is expected to be
+// set later via an import clause in the export data.
+//
+// id identifies a package, usually by a canonical package path like
+// "encoding/json" but possibly by a non-canonical import path like
+// "./json".
+//
+func (p *parser) getPkg(id, name string) *types.Package {
+ // package unsafe is not in the packages maps - handle explicitly
+ if id == "unsafe" {
+ return types.Unsafe
+ }
+
+ pkg := p.localPkgs[id]
+ if pkg == nil {
+ // first import of id from this package
+ pkg = p.sharedPkgs[id]
+ if pkg == nil {
+ // first import of id by this importer;
+ // add (possibly unnamed) pkg to shared packages
+ pkg = types.NewPackage(id, name)
+ p.sharedPkgs[id] = pkg
+ }
+ // add (possibly unnamed) pkg to local packages
+ if p.localPkgs == nil {
+ p.localPkgs = make(map[string]*types.Package)
+ }
+ p.localPkgs[id] = pkg
+ } else if name != "" {
+ // package exists already and we have an expected package name;
+ // make sure names match or set package name if necessary
+ if pname := pkg.Name(); pname == "" {
+ pkg.SetName(name)
+ } else if pname != name {
+ p.errorf("%s package name mismatch: %s (given) vs %s (expected)", id, pname, name)
+ }
+ }
+ return pkg
+}
+
+// parseExportedName is like parseQualifiedName, but
+// the package id is resolved to an imported *types.Package.
+//
+func (p *parser) parseExportedName() (pkg *types.Package, name string) {
+ id, name := p.parseQualifiedName()
+ pkg = p.getPkg(id, "")
+ return
+}
+
+// ----------------------------------------------------------------------------
+// Types
+
+// BasicType = identifier .
+//
+func (p *parser) parseBasicType() types.Type {
+ id := p.expect(scanner.Ident)
+ obj := types.Universe.Lookup(id)
+ if obj, ok := obj.(*types.TypeName); ok {
+ return obj.Type()
+ }
+ p.errorf("not a basic type: %s", id)
+ return nil
+}
+
+// ArrayType = "[" int_lit "]" Type .
+//
+func (p *parser) parseArrayType(parent *types.Package) types.Type {
+ // "[" already consumed and lookahead known not to be "]"
+ lit := p.expect(scanner.Int)
+ p.expect(']')
+ elem := p.parseType(parent)
+ n, err := strconv.ParseInt(lit, 10, 64)
+ if err != nil {
+ p.error(err)
+ }
+ return types.NewArray(elem, n)
+}
+
+// MapType = "map" "[" Type "]" Type .
+//
+func (p *parser) parseMapType(parent *types.Package) types.Type {
+ p.expectKeyword("map")
+ p.expect('[')
+ key := p.parseType(parent)
+ p.expect(']')
+ elem := p.parseType(parent)
+ return types.NewMap(key, elem)
+}
+
+// Name = identifier | "?" | QualifiedName .
+//
+// For unqualified and anonymous names, the returned package is the parent
+// package unless parent == nil, in which case the returned package is the
+// package being imported. (The parent package is not nil if the name
+// is an unqualified struct field or interface method name belonging to a
+// type declared in another package.)
+//
+// For qualified names, the returned package is nil (and not created if
+// it doesn't exist yet) unless materializePkg is set (which creates an
+// unnamed package with valid package path). In the latter case, a
+// subsequent import clause is expected to provide a name for the package.
+//
+func (p *parser) parseName(parent *types.Package, materializePkg bool) (pkg *types.Package, name string) {
+ pkg = parent
+ if pkg == nil {
+ pkg = p.sharedPkgs[p.id]
+ }
+ switch p.tok {
+ case scanner.Ident:
+ name = p.lit
+ p.next()
+ case '?':
+ // anonymous
+ p.next()
+ case '@':
+ // exported name prefixed with package path
+ pkg = nil
+ var id string
+ id, name = p.parseQualifiedName()
+ if materializePkg {
+ pkg = p.getPkg(id, "")
+ }
+ default:
+ p.error("name expected")
+ }
+ return
+}
+
+func deref(typ types.Type) types.Type {
+ if p, _ := typ.(*types.Pointer); p != nil {
+ return p.Elem()
+ }
+ return typ
+}
+
+// Field = Name Type [ string_lit ] .
+//
+func (p *parser) parseField(parent *types.Package) (*types.Var, string) {
+ pkg, name := p.parseName(parent, true)
+
+ if name == "_" {
+ // Blank fields should be package-qualified because they
+ // are unexported identifiers, but gc does not qualify them.
+ // Assuming that the ident belongs to the current package
+ // causes types to change during re-exporting, leading
+ // to spurious "can't assign A to B" errors from go/types.
+ // As a workaround, pretend all blank fields belong
+ // to the same unique dummy package.
+ const blankpkg = "<_>"
+ pkg = p.getPkg(blankpkg, blankpkg)
+ }
+
+ typ := p.parseType(parent)
+ anonymous := false
+ if name == "" {
+ // anonymous field - typ must be T or *T and T must be a type name
+ switch typ := deref(typ).(type) {
+ case *types.Basic: // basic types are named types
+ pkg = nil // objects defined in Universe scope have no package
+ name = typ.Name()
+ case *types.Named:
+ name = typ.Obj().Name()
+ default:
+ p.errorf("anonymous field expected")
+ }
+ anonymous = true
+ }
+ tag := ""
+ if p.tok == scanner.String {
+ s := p.expect(scanner.String)
+ var err error
+ tag, err = strconv.Unquote(s)
+ if err != nil {
+ p.errorf("invalid struct tag %s: %s", s, err)
+ }
+ }
+ return types.NewField(token.NoPos, pkg, name, typ, anonymous), tag
+}
+
+// StructType = "struct" "{" [ FieldList ] "}" .
+// FieldList = Field { ";" Field } .
+//
+func (p *parser) parseStructType(parent *types.Package) types.Type {
+ var fields []*types.Var
+ var tags []string
+
+ p.expectKeyword("struct")
+ p.expect('{')
+ for i := 0; p.tok != '}' && p.tok != scanner.EOF; i++ {
+ if i > 0 {
+ p.expect(';')
+ }
+ fld, tag := p.parseField(parent)
+ if tag != "" && tags == nil {
+ tags = make([]string, i)
+ }
+ if tags != nil {
+ tags = append(tags, tag)
+ }
+ fields = append(fields, fld)
+ }
+ p.expect('}')
+
+ return types.NewStruct(fields, tags)
+}
+
+// Parameter = ( identifier | "?" ) [ "..." ] Type [ string_lit ] .
+//
+func (p *parser) parseParameter() (par *types.Var, isVariadic bool) {
+ _, name := p.parseName(nil, false)
+ // remove gc-specific parameter numbering
+ if i := strings.Index(name, "·"); i >= 0 {
+ name = name[:i]
+ }
+ if p.tok == '.' {
+ p.expectSpecial("...")
+ isVariadic = true
+ }
+ typ := p.parseType(nil)
+ if isVariadic {
+ typ = types.NewSlice(typ)
+ }
+ // ignore argument tag (e.g. "noescape")
+ if p.tok == scanner.String {
+ p.next()
+ }
+ // TODO(gri) should we provide a package?
+ par = types.NewVar(token.NoPos, nil, name, typ)
+ return
+}
+
+// Parameters = "(" [ ParameterList ] ")" .
+// ParameterList = { Parameter "," } Parameter .
+//
+func (p *parser) parseParameters() (list []*types.Var, isVariadic bool) {
+ p.expect('(')
+ for p.tok != ')' && p.tok != scanner.EOF {
+ if len(list) > 0 {
+ p.expect(',')
+ }
+ par, variadic := p.parseParameter()
+ list = append(list, par)
+ if variadic {
+ if isVariadic {
+ p.error("... not on final argument")
+ }
+ isVariadic = true
+ }
+ }
+ p.expect(')')
+
+ return
+}
+
+// Signature = Parameters [ Result ] .
+// Result = Type | Parameters .
+//
+func (p *parser) parseSignature(recv *types.Var) *types.Signature {
+ params, isVariadic := p.parseParameters()
+
+ // optional result type
+ var results []*types.Var
+ if p.tok == '(' {
+ var variadic bool
+ results, variadic = p.parseParameters()
+ if variadic {
+ p.error("... not permitted on result type")
+ }
+ }
+
+ return types.NewSignature(recv, types.NewTuple(params...), types.NewTuple(results...), isVariadic)
+}
+
+// InterfaceType = "interface" "{" [ MethodList ] "}" .
+// MethodList = Method { ";" Method } .
+// Method = Name Signature .
+//
+// The methods of embedded interfaces are always "inlined"
+// by the compiler and thus embedded interfaces are never
+// visible in the export data.
+//
+func (p *parser) parseInterfaceType(parent *types.Package) types.Type {
+ var methods []*types.Func
+
+ p.expectKeyword("interface")
+ p.expect('{')
+ for i := 0; p.tok != '}' && p.tok != scanner.EOF; i++ {
+ if i > 0 {
+ p.expect(';')
+ }
+ pkg, name := p.parseName(parent, true)
+ sig := p.parseSignature(nil)
+ methods = append(methods, types.NewFunc(token.NoPos, pkg, name, sig))
+ }
+ p.expect('}')
+
+ // Complete requires the type's embedded interfaces to be fully defined,
+ // but we do not define any
+ return newInterface(methods, nil).Complete()
+}
+
+// ChanType = ( "chan" [ "<-" ] | "<-" "chan" ) Type .
+//
+func (p *parser) parseChanType(parent *types.Package) types.Type {
+ dir := types.SendRecv
+ if p.tok == scanner.Ident {
+ p.expectKeyword("chan")
+ if p.tok == '<' {
+ p.expectSpecial("<-")
+ dir = types.SendOnly
+ }
+ } else {
+ p.expectSpecial("<-")
+ p.expectKeyword("chan")
+ dir = types.RecvOnly
+ }
+ elem := p.parseType(parent)
+ return types.NewChan(dir, elem)
+}
+
+// Type =
+// BasicType | TypeName | ArrayType | SliceType | StructType |
+// PointerType | FuncType | InterfaceType | MapType | ChanType |
+// "(" Type ")" .
+//
+// BasicType = ident .
+// TypeName = ExportedName .
+// SliceType = "[" "]" Type .
+// PointerType = "*" Type .
+// FuncType = "func" Signature .
+//
+func (p *parser) parseType(parent *types.Package) types.Type {
+ switch p.tok {
+ case scanner.Ident:
+ switch p.lit {
+ default:
+ return p.parseBasicType()
+ case "struct":
+ return p.parseStructType(parent)
+ case "func":
+ // FuncType
+ p.next()
+ return p.parseSignature(nil)
+ case "interface":
+ return p.parseInterfaceType(parent)
+ case "map":
+ return p.parseMapType(parent)
+ case "chan":
+ return p.parseChanType(parent)
+ }
+ case '@':
+ // TypeName
+ pkg, name := p.parseExportedName()
+ return declTypeName(pkg, name).Type()
+ case '[':
+ p.next() // look ahead
+ if p.tok == ']' {
+ // SliceType
+ p.next()
+ return types.NewSlice(p.parseType(parent))
+ }
+ return p.parseArrayType(parent)
+ case '*':
+ // PointerType
+ p.next()
+ return types.NewPointer(p.parseType(parent))
+ case '<':
+ return p.parseChanType(parent)
+ case '(':
+ // "(" Type ")"
+ p.next()
+ typ := p.parseType(parent)
+ p.expect(')')
+ return typ
+ }
+ p.errorf("expected type, got %s (%q)", scanner.TokenString(p.tok), p.lit)
+ return nil
+}
+
+// ----------------------------------------------------------------------------
+// Declarations
+
+// ImportDecl = "import" PackageName PackageId .
+//
+func (p *parser) parseImportDecl() {
+ p.expectKeyword("import")
+ name := p.parsePackageName()
+ p.getPkg(p.parsePackageID(), name)
+}
+
+// int_lit = [ "+" | "-" ] { "0" ... "9" } .
+//
+func (p *parser) parseInt() string {
+ s := ""
+ switch p.tok {
+ case '-':
+ s = "-"
+ p.next()
+ case '+':
+ p.next()
+ }
+ return s + p.expect(scanner.Int)
+}
+
+// number = int_lit [ "p" int_lit ] .
+//
+func (p *parser) parseNumber() (typ *types.Basic, val constant.Value) {
+ // mantissa
+ mant := constant.MakeFromLiteral(p.parseInt(), token.INT, 0)
+ if mant == nil {
+ panic("invalid mantissa")
+ }
+
+ if p.lit == "p" {
+ // exponent (base 2)
+ p.next()
+ exp, err := strconv.ParseInt(p.parseInt(), 10, 0)
+ if err != nil {
+ p.error(err)
+ }
+ if exp < 0 {
+ denom := constant.MakeInt64(1)
+ denom = constant.Shift(denom, token.SHL, uint(-exp))
+ typ = types.Typ[types.UntypedFloat]
+ val = constant.BinaryOp(mant, token.QUO, denom)
+ return
+ }
+ if exp > 0 {
+ mant = constant.Shift(mant, token.SHL, uint(exp))
+ }
+ typ = types.Typ[types.UntypedFloat]
+ val = mant
+ return
+ }
+
+ typ = types.Typ[types.UntypedInt]
+ val = mant
+ return
+}
+
+// ConstDecl = "const" ExportedName [ Type ] "=" Literal .
+// Literal = bool_lit | int_lit | float_lit | complex_lit | rune_lit | string_lit .
+// bool_lit = "true" | "false" .
+// complex_lit = "(" float_lit "+" float_lit "i" ")" .
+// rune_lit = "(" int_lit "+" int_lit ")" .
+// string_lit = `"` { unicode_char } `"` .
+//
+func (p *parser) parseConstDecl() {
+ p.expectKeyword("const")
+ pkg, name := p.parseExportedName()
+
+ var typ0 types.Type
+ if p.tok != '=' {
+ // constant types are never structured - no need for parent type
+ typ0 = p.parseType(nil)
+ }
+
+ p.expect('=')
+ var typ types.Type
+ var val constant.Value
+ switch p.tok {
+ case scanner.Ident:
+ // bool_lit
+ if p.lit != "true" && p.lit != "false" {
+ p.error("expected true or false")
+ }
+ typ = types.Typ[types.UntypedBool]
+ val = constant.MakeBool(p.lit == "true")
+ p.next()
+
+ case '-', scanner.Int:
+ // int_lit
+ typ, val = p.parseNumber()
+
+ case '(':
+ // complex_lit or rune_lit
+ p.next()
+ if p.tok == scanner.Char {
+ p.next()
+ p.expect('+')
+ typ = types.Typ[types.UntypedRune]
+ _, val = p.parseNumber()
+ p.expect(')')
+ break
+ }
+ _, re := p.parseNumber()
+ p.expect('+')
+ _, im := p.parseNumber()
+ p.expectKeyword("i")
+ p.expect(')')
+ typ = types.Typ[types.UntypedComplex]
+ val = constant.BinaryOp(re, token.ADD, constant.MakeImag(im))
+
+ case scanner.Char:
+ // rune_lit
+ typ = types.Typ[types.UntypedRune]
+ val = constant.MakeFromLiteral(p.lit, token.CHAR, 0)
+ p.next()
+
+ case scanner.String:
+ // string_lit
+ typ = types.Typ[types.UntypedString]
+ val = constant.MakeFromLiteral(p.lit, token.STRING, 0)
+ p.next()
+
+ default:
+ p.errorf("expected literal got %s", scanner.TokenString(p.tok))
+ }
+
+ if typ0 == nil {
+ typ0 = typ
+ }
+
+ pkg.Scope().Insert(types.NewConst(token.NoPos, pkg, name, typ0, val))
+}
+
+// TypeDecl = "type" ExportedName Type .
+//
+func (p *parser) parseTypeDecl() {
+ p.expectKeyword("type")
+ pkg, name := p.parseExportedName()
+ obj := declTypeName(pkg, name)
+
+ // The type object may have been imported before and thus already
+ // have a type associated with it. We still need to parse the type
+ // structure, but throw it away if the object already has a type.
+ // This ensures that all imports refer to the same type object for
+ // a given type declaration.
+ typ := p.parseType(pkg)
+
+ if name := obj.Type().(*types.Named); name.Underlying() == nil {
+ name.SetUnderlying(typ)
+ }
+}
+
+// VarDecl = "var" ExportedName Type .
+//
+func (p *parser) parseVarDecl() {
+ p.expectKeyword("var")
+ pkg, name := p.parseExportedName()
+ typ := p.parseType(pkg)
+ pkg.Scope().Insert(types.NewVar(token.NoPos, pkg, name, typ))
+}
+
+// Func = Signature [ Body ] .
+// Body = "{" ... "}" .
+//
+func (p *parser) parseFunc(recv *types.Var) *types.Signature {
+ sig := p.parseSignature(recv)
+ if p.tok == '{' {
+ p.next()
+ for i := 1; i > 0; p.next() {
+ switch p.tok {
+ case '{':
+ i++
+ case '}':
+ i--
+ }
+ }
+ }
+ return sig
+}
+
+// MethodDecl = "func" Receiver Name Func .
+// Receiver = "(" ( identifier | "?" ) [ "*" ] ExportedName ")" .
+//
+func (p *parser) parseMethodDecl() {
+ // "func" already consumed
+ p.expect('(')
+ recv, _ := p.parseParameter() // receiver
+ p.expect(')')
+
+ // determine receiver base type object
+ base := deref(recv.Type()).(*types.Named)
+
+ // parse method name, signature, and possibly inlined body
+ _, name := p.parseName(nil, false)
+ sig := p.parseFunc(recv)
+
+ // methods always belong to the same package as the base type object
+ pkg := base.Obj().Pkg()
+
+ // add method to type unless type was imported before
+ // and method exists already
+ // TODO(gri) This leads to a quadratic algorithm - ok for now because method counts are small.
+ base.AddMethod(types.NewFunc(token.NoPos, pkg, name, sig))
+}
+
+// FuncDecl = "func" ExportedName Func .
+//
+func (p *parser) parseFuncDecl() {
+ // "func" already consumed
+ pkg, name := p.parseExportedName()
+ typ := p.parseFunc(nil)
+ pkg.Scope().Insert(types.NewFunc(token.NoPos, pkg, name, typ))
+}
+
+// Decl = [ ImportDecl | ConstDecl | TypeDecl | VarDecl | FuncDecl | MethodDecl ] "\n" .
+//
+func (p *parser) parseDecl() {
+ if p.tok == scanner.Ident {
+ switch p.lit {
+ case "import":
+ p.parseImportDecl()
+ case "const":
+ p.parseConstDecl()
+ case "type":
+ p.parseTypeDecl()
+ case "var":
+ p.parseVarDecl()
+ case "func":
+ p.next() // look ahead
+ if p.tok == '(' {
+ p.parseMethodDecl()
+ } else {
+ p.parseFuncDecl()
+ }
+ }
+ }
+ p.expect('\n')
+}
+
+// ----------------------------------------------------------------------------
+// Export
+
+// Export = "PackageClause { Decl } "$$" .
+// PackageClause = "package" PackageName [ "safe" ] "\n" .
+//
+func (p *parser) parseExport() *types.Package {
+ p.expectKeyword("package")
+ name := p.parsePackageName()
+ if p.tok == scanner.Ident && p.lit == "safe" {
+ // package was compiled with -u option - ignore
+ p.next()
+ }
+ p.expect('\n')
+
+ pkg := p.getPkg(p.id, name)
+
+ for p.tok != '$' && p.tok != scanner.EOF {
+ p.parseDecl()
+ }
+
+ if ch := p.scanner.Peek(); p.tok != '$' || ch != '$' {
+ // don't call next()/expect() since reading past the
+ // export data may cause scanner errors (e.g. NUL chars)
+ p.errorf("expected '$$', got %s %c", scanner.TokenString(p.tok), ch)
+ }
+
+ if n := p.scanner.ErrorCount; n != 0 {
+ p.errorf("expected no scanner errors, got %d", n)
+ }
+
+ // Record all locally referenced packages as imports.
+ var imports []*types.Package
+ for id, pkg2 := range p.localPkgs {
+ if pkg2.Name() == "" {
+ p.errorf("%s package has no name", id)
+ }
+ if id == p.id {
+ continue // avoid self-edge
+ }
+ imports = append(imports, pkg2)
+ }
+ sort.Sort(byPath(imports))
+ pkg.SetImports(imports)
+
+ // package was imported completely and without errors
+ pkg.MarkComplete()
+
+ return pkg
+}
+
+type byPath []*types.Package
+
+func (a byPath) Len() int { return len(a) }
+func (a byPath) Swap(i, j int) { a[i], a[j] = a[j], a[i] }
+func (a byPath) Less(i, j int) bool { return a[i].Path() < a[j].Path() }
projects / dotfiles / .git / blobdiff