Golang Object.Pos方法代码示例

func (f *Function) addParamObj(obj types.Object) *Parameter {
	name := obj.Name()
	if name == "" {
		name = fmt.Sprintf("arg%d", len(f.Params))
	}
	param := f.addParam(name, obj.Type(), obj.Pos())
	param.object = obj
	return param
}

func (v *visitor) decl(obj types.Object) {
	key := getKey(obj)
	if _, ok := v.uses[key]; !ok {
		v.uses[key] = 0
	}
	if _, ok := v.positions[key]; !ok {
		v.positions[key] = v.prog.Fset.Position(obj.Pos())
	}
}

// memberFromObject populates package pkg with a member for the
// typechecker object obj.
//
// For objects from Go source code, syntax is the associated syntax
// tree (for funcs and vars only); it will be used during the build
// phase.
//
func memberFromObject(pkg *Package, obj types.Object, syntax ast.Node) {
	name := obj.Name()
	switch obj := obj.(type) {
	case *types.TypeName:
		pkg.Members[name] = &Type{
			object: obj,
			pkg:    pkg,
		}

	case *types.Const:
		c := &NamedConst{
			object: obj,
			Value:  NewConst(obj.Val(), obj.Type()),
			pkg:    pkg,
		}
		pkg.values[obj] = c.Value
		pkg.Members[name] = c

	case *types.Var:
		g := &Global{
			Pkg:    pkg,
			name:   name,
			object: obj,
			typ:    types.NewPointer(obj.Type()), // address
			pos:    obj.Pos(),
		}
		pkg.values[obj] = g
		pkg.Members[name] = g

	case *types.Func:
		sig := obj.Type().(*types.Signature)
		if sig.Recv() == nil && name == "init" {
			pkg.ninit++
			name = fmt.Sprintf("init#%d", pkg.ninit)
		}
		fn := &Function{
			name:      name,
			object:    obj,
			Signature: sig,
			syntax:    syntax,
			pos:       obj.Pos(),
			Pkg:       pkg,
			Prog:      pkg.Prog,
		}
		if syntax == nil {
			fn.Synthetic = "loaded from gc object file"
		}

		pkg.values[obj] = fn
		if sig.Recv() == nil {
			pkg.Members[name] = fn // package-level function
		}

	default: // (incl. *types.Package)
		panic("unexpected Object type: " + obj.String())
	}
}

// addSpilledParam declares a parameter that is pre-spilled to the
// stack; the function body will load/store the spilled location.
// Subsequent lifting will eliminate spills where possible.
//
func (f *Function) addSpilledParam(obj types.Object) {
	param := f.addParamObj(obj)
	spill := &Alloc{Comment: obj.Name()}
	spill.setType(types.NewPointer(obj.Type()))
	spill.setPos(obj.Pos())
	f.objects[obj] = spill
	f.Locals = append(f.Locals, spill)
	f.emit(spill)
	f.emit(&Store{Addr: spill, Val: param})
}

func newObject(obj types.Object, sel *types.Selection) (*Object, error) {
	// WARN: Dev only
	if sel != nil {
		return newSelector(sel)
	}
	o := &Object{
		Name: obj.Name(),
		pos:  obj.Pos(),
	}
	o.setPkg(obj.Pkg())
	switch typ := obj.(type) {
	case *types.PkgName:
		o.ObjType = Package
		if p := typ.Imported(); p != nil {
			o.setPkg(p)
		}
	case *types.Const:
		o.ObjType = Const
	case *types.TypeName:
		o.ObjType = TypeName
	case *types.Var:
		o.ObjType = Var
		o.IsField = typ.IsField()
		if t, ok := derefType(typ.Type()).(*types.Named); ok {
			o.ObjType = TypeName
			// WARN: This looks wrong
			o.IsField = false
			if obj := t.Obj(); obj != nil {
				o.Name = obj.Name()
				o.setPkg(obj.Pkg())
				o.pos = obj.Pos() // WARN
			}
		}
	case *types.Func:
		if sig := typ.Type().(*types.Signature); sig != nil {
			o.ObjType = Func
		} else {
			switch r := derefType(sig.Recv().Type()).(type) {
			case *types.Named:
				o.ObjType = Method
				o.setParent(r.Obj())
			case *types.Interface:
				o.ObjType = Interface
			default:
				// This should never happen
			}
		}
	default:
		// TODO: log type
		o.ObjType = Bad
	}
	return o, nil
}

func (r *Unexporter) selectionConflict(objsToUpdate map[types.Object]string, from types.Object, to string, delta int, syntax *ast.SelectorExpr, obj types.Object) {
	rename := r.errorf(from.Pos(), "renaming this %s %q to %q",
		objectKind(from), from.Name(), to)

	switch {
	case delta < 0:
		// analogous to sub-block conflict
		r.warn(from, rename,
			r.errorf(syntax.Sel.Pos(),
				"\twould change the referent of this selection"),
			r.errorf(obj.Pos(), "\tof this %s", objectKind(obj)))
	case delta == 0:
		// analogous to same-block conflict
		r.warn(from, rename,
			r.errorf(syntax.Sel.Pos(),
				"\twould make this reference ambiguous"),
			r.errorf(obj.Pos(), "\twith this %s", objectKind(obj)))
	case delta > 0:
		// analogous to super-block conflict
		r.warn(from, rename,
			r.errorf(syntax.Sel.Pos(),
				"\twould shadow this selection"),
			r.errorf(obj.Pos(), "\tof the %s declared here",
				objectKind(obj)))
	}
}

func (r *renamer) checkExport(id *ast.Ident, pkg *types.Package, from types.Object) bool {
	// Reject cross-package references if r.to is unexported.
	// (Such references may be qualified identifiers or field/method
	// selections.)
	if !ast.IsExported(r.to) && pkg != from.Pkg() {
		r.errorf(from.Pos(),
			"renaming this %s %q to %q would make it unexported",
			objectKind(from), from.Name(), r.to)
		r.errorf(id.Pos(), "\tbreaking references from packages such as %q",
			pkg.Path())
		return false
	}
	return true
}

func (g *Grapher) makeDefInfo(obj types.Object) (*DefKey, *defInfo, error) {
	switch obj := obj.(type) {
	case *types.Builtin:
		return &DefKey{"builtin", []string{obj.Name()}}, &defInfo{pkgscope: false, exported: true}, nil
	case *types.Nil:
		return &DefKey{"builtin", []string{"nil"}}, &defInfo{pkgscope: false, exported: true}, nil
	case *types.TypeName:
		if basic, ok := obj.Type().(*types.Basic); ok {
			return &DefKey{"builtin", []string{basic.Name()}}, &defInfo{pkgscope: false, exported: true}, nil
		}
		if obj.Name() == "error" {
			return &DefKey{"builtin", []string{obj.Name()}}, &defInfo{pkgscope: false, exported: true}, nil
		}
	case *types.PkgName:
		return &DefKey{obj.Imported().Path(), []string{}}, &defInfo{pkgscope: false, exported: true}, nil
	case *types.Const:
		var pkg string
		if obj.Pkg() == nil {
			pkg = "builtin"
		} else {
			pkg = obj.Pkg().Path()
		}
		if obj.Val().Kind() == exact.Bool && pkg == "builtin" {
			return &DefKey{pkg, []string{obj.Name()}}, &defInfo{pkgscope: false, exported: true}, nil
		}
	}

	if obj.Pkg() == nil {
		// builtin
		return &DefKey{"builtin", []string{obj.Name()}}, &defInfo{pkgscope: false, exported: true}, nil
	}

	path := g.path(obj)

	// Handle the case where a dir has 2 main packages that are not
	// intended to be compiled together and have overlapping def
	// paths. Prefix the def path with the filename.
	if obj.Pkg().Name() == "main" {
		p := g.program.Fset.Position(obj.Pos())
		path = append([]string{filepath.Base(p.Filename)}, path...)
	}

	return &DefKey{obj.Pkg().Path(), path}, &defInfo{pkgscope: g.pkgscope[obj], exported: g.exported[obj]}, nil
}

func getEnclosingStruct(object types.Object) types.Type {
	pkgScope := object.Pkg().Scope()
	s := pkgScope.Innermost(object.Pos())
	if s.Parent() == pkgScope {
		s = pkgScope
	}

	var obj types.Object
	for _, name := range s.Names() {
		o := s.Lookup(name)
		if o.Pos() <= object.Pos() && (obj == nil || o.Pos() > obj.Pos()) {
			obj = o
		}
	}

	if obj == nil {
		return nil
	}
	if obj == object {
		return obj.Type()
	}

	t := obj.Type().Underlying().(*types.Struct)
	for {
		var f types.Object
		for i := 0; i < t.NumFields(); i++ {
			field := t.Field(i)
			if field == object {
				return t
			}
			if field.Pos() <= object.Pos() && (f == nil || field.Pos() > f.Pos()) {
				f = field
			}
		}
		if fs, ok := f.Type().(*types.Struct); ok {
			t = fs
		} else {
			break
		}
	}

	return t
}

func (r *Unexporter) checkInLocalScope(objsToUpdate map[types.Object]string, from types.Object, to string) {
	info := r.packages[from.Pkg()]

	// Is this object an implicit local var for a type switch?
	// Each case has its own var, whose position is the decl of y,
	// but Ident in that decl does not appear in the Uses map.
	//
	//   switch y := x.(type) {	 // Defs[Ident(y)] is undefined
	//   case int:    print(y)       // Implicits[CaseClause(int)]    = Var(y_int)
	//   case string: print(y)       // Implicits[CaseClause(string)] = Var(y_string)
	//   }
	//
	var isCaseVar bool
	for syntax, obj := range info.Implicits {
		if _, ok := syntax.(*ast.CaseClause); ok && obj.Pos() == from.Pos() {
			isCaseVar = true
			r.check(objsToUpdate, obj, to)
		}
	}

	r.checkInLexicalScope(objsToUpdate, from, to, info)

	// Finally, if this was a type switch, change the variable y.
	if isCaseVar {
		_, path, _ := r.iprog.PathEnclosingInterval(from.Pos(), from.Pos())
		path[0].(*ast.Ident).Name = to // path is [Ident AssignStmt TypeSwitchStmt...]
	}
}

// checkInPackageBlock performs safety checks for renames of
// func/var/const/type objects in the package block.
func (r *renamer) checkInPackageBlock(from types.Object) {
	// Check that there are no references to the name from another
	// package if the renaming would make it unexported.
	if ast.IsExported(from.Name()) && !ast.IsExported(r.to) {
		for pkg, info := range r.packages {
			if pkg == from.Pkg() {
				continue
			}
			if id := someUse(info, from); id != nil &&
				!r.checkExport(id, pkg, from) {
				break
			}
		}
	}

	info := r.packages[from.Pkg()]

	// Check that in the package block, "init" is a function, and never referenced.
	if r.to == "init" {
		kind := objectKind(from)
		if kind == "func" {
			// Reject if intra-package references to it exist.
			for id, obj := range info.Uses {
				if obj == from {
					r.errorf(from.Pos(),
						"renaming this func %q to %q would make it a package initializer",
						from.Name(), r.to)
					r.errorf(id.Pos(), "\tbut references to it exist")
					break
				}
			}
		} else {
			r.errorf(from.Pos(), "you cannot have a %s at package level named %q",
				kind, r.to)
		}
	}

	// Check for conflicts between package block and all file blocks.
	for _, f := range info.Files {
		fileScope := info.Info.Scopes[f]
		b, prev := fileScope.LookupParent(r.to, token.NoPos)
		if b == fileScope {
			r.errorf(from.Pos(), "renaming this %s %q to %q would conflict",
				objectKind(from), from.Name(), r.to)
			r.errorf(prev.Pos(), "\twith this %s",
				objectKind(prev))
			return // since checkInPackageBlock would report redundant errors
		}
	}

	// Check for conflicts in lexical scope.
	if from.Exported() {
		for _, info := range r.packages {
			r.checkInLexicalScope(from, info)
		}
	} else {
		r.checkInLexicalScope(from, info)
	}
}

// checkInPackageBlock performs safety checks for renames of
// func/var/const/type objects in the package block.
func (r *Unexporter) checkInPackageBlock(objsToUpdate map[types.Object]string, from types.Object, to string) {
	// Check that there are no references to the name from another
	// package if the renaming would make it unexported.
	if ast.IsExported(from.Name()) && !ast.IsExported(to) {
		for pkg, info := range r.packages {
			if pkg == from.Pkg() {
				continue
			}
			if id := someUse(info, from); id != nil &&
				!r.checkExport(id, pkg, from, to) {
				break
			}
		}
	}

	info := r.packages[from.Pkg()]
	lexinfo := r.lexInfo(info)

	// Check that in the package block, "init" is a function, and never referenced.
	if to == "init" {
		kind := objectKind(from)
		if kind == "func" {
			// Reject if intra-package references to it exist.
			if refs := lexinfo.Refs[from]; len(refs) > 0 {
				r.warn(from,
					r.errorf(from.Pos(),
						"renaming this func %q to %q would make it a package initializer",
						from.Name(), to),
					r.errorf(refs[0].Id.Pos(), "\tbut references to it exist"))
			}
		} else {
			r.warn(from, r.errorf(from.Pos(), "you cannot have a %s at package level named %q",
				kind, to))
		}
	}

	// Check for conflicts between package block and all file blocks.
	for _, f := range info.Files {
		if prev, b := lexinfo.Blocks[f].Lookup(to); b == lexinfo.Blocks[f] {
			r.warn(from,
				r.errorf(from.Pos(), "renaming this %s %q to %q would conflict",
					objectKind(from), from.Name(), to),
				r.errorf(prev.Pos(), "\twith this %s",
					objectKind(prev)))
			return // since checkInPackageBlock would report redundant errors
		}
	}

	// Check for conflicts in lexical scope.
	if from.Exported() {
		for _, info := range r.packages {
			r.checkInLexicalScope(objsToUpdate, from, to, info)
		}
	} else {
		r.checkInLexicalScope(objsToUpdate, from, to, info)
	}
}

// check performs safety checks of the renaming of the 'from' object to r.to.
func (r *renamer) check(from types.Object) {
	if r.objsToUpdate[from] {
		return
	}
	r.objsToUpdate[from] = true

	// NB: order of conditions is important.
	if from_, ok := from.(*types.PkgName); ok {
		r.checkInFileBlock(from_)
	} else if from_, ok := from.(*types.Label); ok {
		r.checkLabel(from_)
	} else if isPackageLevel(from) {
		r.checkInPackageBlock(from)
	} else if v, ok := from.(*types.Var); ok && v.IsField() {
		r.checkStructField(v)
	} else if f, ok := from.(*types.Func); ok && recv(f) != nil {
		r.checkMethod(f)
	} else if isLocal(from) {
		r.checkInLocalScope(from)
	} else {
		r.errorf(from.Pos(), "unexpected %s object %q (please report a bug)\n",
			objectKind(from), from)
	}
}

func (r *Unexporter) check(objsToUpdate map[types.Object]string, from types.Object, to string) {
	if _, ok := objsToUpdate[from]; ok {
		return
	}
	objsToUpdate[from] = to

	// NB: order of conditions is important.
	if from_, ok := from.(*types.PkgName); ok {
		r.checkInFileBlock(objsToUpdate, from_, to)
	} else if from_, ok := from.(*types.Label); ok {
		r.checkLabel(from_, to)
	} else if isPackageLevel(from) {
		r.checkInPackageBlock(objsToUpdate, from, to)
	} else if v, ok := from.(*types.Var); ok && v.IsField() {
		r.checkStructField(objsToUpdate, v, to)
	} else if f, ok := from.(*types.Func); ok && recv(f) != nil {
		r.checkMethod(objsToUpdate, f, to)
	} else if isLocal(from) {
		r.checkInLocalScope(objsToUpdate, from, to)
	} else {
		r.errorf(from.Pos(), "unexpected %s object %q (please report a bug)\n",
			objectKind(from), from)
	}
}

func (r *renamer) selectionConflict(from types.Object, delta int, syntax *ast.SelectorExpr, obj types.Object) {
	r.errorf(from.Pos(), "renaming this %s %q to %q",
		objectKind(from), from.Name(), r.to)

	switch {
	case delta < 0:
		// analogous to sub-block conflict
		r.errorf(syntax.Sel.Pos(),
			"\twould change the referent of this selection")
		r.errorf(obj.Pos(), "\tto this %s", objectKind(obj))
	case delta == 0:
		// analogous to same-block conflict
		r.errorf(syntax.Sel.Pos(),
			"\twould make this reference ambiguous")
		r.errorf(obj.Pos(), "\twith this %s", objectKind(obj))
	case delta > 0:
		// analogous to super-block conflict
		r.errorf(syntax.Sel.Pos(),
			"\twould shadow this selection")
		r.errorf(obj.Pos(), "\tto the %s declared here",
			objectKind(obj))
	}
}