2 // Copyright 2013 The Go Authors. All rights reserved.
3 // Use of this source code is governed by a BSD-style
4 // license that can be found in the LICENSE file.
10 "cmd/compile/internal/syntax"
16 // An Object describes a named language entity such as a package,
17 // constant, type, variable, function (incl. methods), or label.
18 // All objects implement the Object interface.
20 type Object interface {
21 Parent() *Scope // scope in which this object is declared; nil for methods and struct fields
22 Pos() syntax.Pos // position of object identifier in declaration
23 Pkg() *Package // package to which this object belongs; nil for labels and objects in the Universe scope
24 Name() string // package local object name
25 Type() Type // object type
26 Exported() bool // reports whether the name starts with a capital letter
27 Id() string // object name if exported, qualified name if not exported (see func Id)
29 // String returns a human-readable string of the object.
32 // order reflects a package-level object's source order: if object
33 // a is before object b in the source, then a.order() < b.order().
34 // order returns a value > 0 for package-level objects; it returns
35 // 0 for all other objects (including objects in file scopes).
38 // color returns the object's color.
41 // setType sets the type of the object.
44 // setOrder sets the order number of the object. It must be > 0.
47 // setColor sets the object's color. It must not be white.
50 // setParent sets the parent scope of the object.
53 // sameId reports whether obj.Id() and Id(pkg, name) are the same.
54 sameId(pkg *Package, name string) bool
56 // scopePos returns the start position of the scope of this Object
59 // setScopePos sets the start position of the scope for this Object.
60 setScopePos(pos syntax.Pos)
63 // Id returns name if it is exported, otherwise it
64 // returns the name qualified with the package path.
65 func Id(pkg *Package, name string) string {
66 if token.IsExported(name) {
69 // unexported names need the package path for differentiation
70 // (if there's no package, make sure we don't start with '.'
71 // as that may change the order of methods between a setup
72 // inside a package and outside a package - which breaks some
75 // pkg is nil for objects in Universe scope and possibly types
76 // introduced via Eval (see also comment in object.sameId)
77 if pkg != nil && pkg.path != "" {
80 return path + "." + name
83 // An object implements the common parts of an Object.
95 // color encodes the color of an object (see Checker.objDecl for details).
98 // An object may be painted in one of three colors.
99 // Color values other than white or black are considered grey.
103 grey // must be > white and black
106 func (c color) String() string {
117 // colorFor returns the (initial) color for an object depending on
118 // whether its type t is known or not.
119 func colorFor(t Type) color {
126 // Parent returns the scope in which the object is declared.
127 // The result is nil for methods and struct fields.
128 func (obj *object) Parent() *Scope { return obj.parent }
130 // Pos returns the declaration position of the object's identifier.
131 func (obj *object) Pos() syntax.Pos { return obj.pos }
133 // Pkg returns the package to which the object belongs.
134 // The result is nil for labels and objects in the Universe scope.
135 func (obj *object) Pkg() *Package { return obj.pkg }
137 // Name returns the object's (package-local, unqualified) name.
138 func (obj *object) Name() string { return obj.name }
140 // Type returns the object's type.
141 func (obj *object) Type() Type { return obj.typ }
143 // Exported reports whether the object is exported (starts with a capital letter).
144 // It doesn't take into account whether the object is in a local (function) scope
146 func (obj *object) Exported() bool { return token.IsExported(obj.name) }
148 // Id is a wrapper for Id(obj.Pkg(), obj.Name()).
149 func (obj *object) Id() string { return Id(obj.pkg, obj.name) }
151 func (obj *object) String() string { panic("abstract") }
152 func (obj *object) order() uint32 { return obj.order_ }
153 func (obj *object) color() color { return obj.color_ }
154 func (obj *object) scopePos() syntax.Pos { return obj.scopePos_ }
156 func (obj *object) setParent(parent *Scope) { obj.parent = parent }
157 func (obj *object) setType(typ Type) { obj.typ = typ }
158 func (obj *object) setOrder(order uint32) { assert(order > 0); obj.order_ = order }
159 func (obj *object) setColor(color color) { assert(color != white); obj.color_ = color }
160 func (obj *object) setScopePos(pos syntax.Pos) { obj.scopePos_ = pos }
162 func (obj *object) sameId(pkg *Package, name string) bool {
164 // "Two identifiers are different if they are spelled differently,
165 // or if they appear in different packages and are not exported.
166 // Otherwise, they are the same."
167 if name != obj.name {
174 // not exported, so packages must be the same (pkg == nil for
175 // fields in Universe scope; this can only happen for types
176 // introduced via Eval)
177 if pkg == nil || obj.pkg == nil {
178 return pkg == obj.pkg
180 // pkg != nil && obj.pkg != nil
181 return pkg.path == obj.pkg.path
184 // A PkgName represents an imported Go package.
185 // PkgNames don't have a type.
186 type PkgName struct {
189 used bool // set if the package was used
192 // NewPkgName returns a new PkgName object representing an imported package.
193 // The remaining arguments set the attributes found with all Objects.
194 func NewPkgName(pos syntax.Pos, pkg *Package, name string, imported *Package) *PkgName {
195 return &PkgName{object{nil, pos, pkg, name, Typ[Invalid], 0, black, nopos}, imported, false}
198 // Imported returns the package that was imported.
199 // It is distinct from Pkg(), which is the package containing the import statement.
200 func (obj *PkgName) Imported() *Package { return obj.imported }
202 // A Const represents a declared constant.
208 // NewConst returns a new constant with value val.
209 // The remaining arguments set the attributes found with all Objects.
210 func NewConst(pos syntax.Pos, pkg *Package, name string, typ Type, val constant.Value) *Const {
211 return &Const{object{nil, pos, pkg, name, typ, 0, colorFor(typ), nopos}, val}
214 // Val returns the constant's value.
215 func (obj *Const) Val() constant.Value { return obj.val }
217 func (*Const) isDependency() {} // a constant may be a dependency of an initialization expression
219 // A TypeName represents a name for a (defined or alias) type.
220 type TypeName struct {
224 // NewTypeName returns a new type name denoting the given typ.
225 // The remaining arguments set the attributes found with all Objects.
227 // The typ argument may be a defined (Named) type or an alias type.
228 // It may also be nil such that the returned TypeName can be used as
229 // argument for NewNamed, which will set the TypeName's type as a side-
231 func NewTypeName(pos syntax.Pos, pkg *Package, name string, typ Type) *TypeName {
232 return &TypeName{object{nil, pos, pkg, name, typ, 0, colorFor(typ), nopos}}
235 // IsAlias reports whether obj is an alias name for a type.
236 func (obj *TypeName) IsAlias() bool {
237 switch t := obj.typ.(type) {
241 // unsafe.Pointer is not an alias.
242 if obj.pkg == Unsafe {
245 // Any user-defined type name for a basic type is an alias for a
246 // basic type (because basic types are pre-declared in the Universe
247 // scope, outside any package scope), and so is any type name with
248 // a different name than the name of the basic type it refers to.
249 // Additionally, we need to look for "byte" and "rune" because they
250 // are aliases but have the same names (for better error messages).
251 return obj.pkg != nil || t.name != obj.name || t == universeByte || t == universeRune
259 // A Variable represents a declared variable (including function parameters and results, and struct fields).
262 embedded bool // if set, the variable is an embedded struct field, and name is the type name
263 isField bool // var is struct field
264 used bool // set if the variable was used
267 // NewVar returns a new variable.
268 // The arguments set the attributes found with all Objects.
269 func NewVar(pos syntax.Pos, pkg *Package, name string, typ Type) *Var {
270 return &Var{object: object{nil, pos, pkg, name, typ, 0, colorFor(typ), nopos}}
273 // NewParam returns a new variable representing a function parameter.
274 func NewParam(pos syntax.Pos, pkg *Package, name string, typ Type) *Var {
275 return &Var{object: object{nil, pos, pkg, name, typ, 0, colorFor(typ), nopos}, used: true} // parameters are always 'used'
278 // NewField returns a new variable representing a struct field.
279 // For embedded fields, the name is the unqualified type name
280 /// under which the field is accessible.
281 func NewField(pos syntax.Pos, pkg *Package, name string, typ Type, embedded bool) *Var {
282 return &Var{object: object{nil, pos, pkg, name, typ, 0, colorFor(typ), nopos}, embedded: embedded, isField: true}
285 // Anonymous reports whether the variable is an embedded field.
286 // Same as Embedded; only present for backward-compatibility.
287 func (obj *Var) Anonymous() bool { return obj.embedded }
289 // Embedded reports whether the variable is an embedded field.
290 func (obj *Var) Embedded() bool { return obj.embedded }
292 // IsField reports whether the variable is a struct field.
293 func (obj *Var) IsField() bool { return obj.isField }
295 func (*Var) isDependency() {} // a variable may be a dependency of an initialization expression
297 // A Func represents a declared function, concrete method, or abstract
298 // (interface) method. Its Type() is always a *Signature.
299 // An abstract method may belong to many interfaces due to embedding.
302 hasPtrRecv bool // only valid for methods that don't have a type yet
305 // NewFunc returns a new function with the given signature, representing
306 // the function's type.
307 func NewFunc(pos syntax.Pos, pkg *Package, name string, sig *Signature) *Func {
308 // don't store a (typed) nil signature
313 return &Func{object{nil, pos, pkg, name, typ, 0, colorFor(typ), nopos}, false}
316 // FullName returns the package- or receiver-type-qualified name of
317 // function or method obj.
318 func (obj *Func) FullName() string {
320 writeFuncName(&buf, obj, nil)
324 // Scope returns the scope of the function's body block.
325 func (obj *Func) Scope() *Scope { return obj.typ.(*Signature).scope }
327 func (*Func) isDependency() {} // a function may be a dependency of an initialization expression
329 // A Label represents a declared label.
330 // Labels don't have a type.
333 used bool // set if the label was used
336 // NewLabel returns a new label.
337 func NewLabel(pos syntax.Pos, pkg *Package, name string) *Label {
338 return &Label{object{pos: pos, pkg: pkg, name: name, typ: Typ[Invalid], color_: black}, false}
341 // A Builtin represents a built-in function.
342 // Builtins don't have a valid type.
343 type Builtin struct {
348 func newBuiltin(id builtinId) *Builtin {
349 return &Builtin{object{name: predeclaredFuncs[id].name, typ: Typ[Invalid], color_: black}, id}
352 // Nil represents the predeclared value nil.
357 func writeObject(buf *bytes.Buffer, obj Object, qf Qualifier) {
361 switch obj := obj.(type) {
363 fmt.Fprintf(buf, "package %s", obj.Name())
364 if path := obj.imported.path; path != "" && path != obj.name {
365 fmt.Fprintf(buf, " (%q)", path)
370 buf.WriteString("const")
374 buf.WriteString("type")
378 buf.WriteString("field")
380 buf.WriteString("var")
384 buf.WriteString("func ")
385 writeFuncName(buf, obj, qf)
387 WriteSignature(buf, typ.(*Signature), qf)
392 buf.WriteString("label")
396 buf.WriteString("builtin")
400 buf.WriteString("nil")
404 panic(fmt.Sprintf("writeObject(%T)", obj))
409 // For package-level objects, qualify the name.
410 if obj.Pkg() != nil && obj.Pkg().scope.Lookup(obj.Name()) == obj {
411 writePackage(buf, obj.Pkg(), qf)
413 buf.WriteString(obj.Name())
420 // We have a type object: Don't print anything more for
421 // basic types since there's no more information (names
422 // are the same; see also comment in TypeName.IsAlias).
423 if _, ok := typ.(*Basic); ok {
427 buf.WriteString(" =")
434 WriteType(buf, typ, qf)
437 func writePackage(buf *bytes.Buffer, pkg *Package, qf Qualifier) {
453 // ObjectString returns the string form of obj.
454 // The Qualifier controls the printing of
455 // package-level objects, and may be nil.
456 func ObjectString(obj Object, qf Qualifier) string {
458 writeObject(&buf, obj, qf)
462 func (obj *PkgName) String() string { return ObjectString(obj, nil) }
463 func (obj *Const) String() string { return ObjectString(obj, nil) }
464 func (obj *TypeName) String() string { return ObjectString(obj, nil) }
465 func (obj *Var) String() string { return ObjectString(obj, nil) }
466 func (obj *Func) String() string { return ObjectString(obj, nil) }
467 func (obj *Label) String() string { return ObjectString(obj, nil) }
468 func (obj *Builtin) String() string { return ObjectString(obj, nil) }
469 func (obj *Nil) String() string { return ObjectString(obj, nil) }
471 func writeFuncName(buf *bytes.Buffer, f *Func, qf Qualifier) {
473 sig := f.typ.(*Signature)
474 if recv := sig.Recv(); recv != nil {
476 if _, ok := recv.Type().(*Interface); ok {
477 // gcimporter creates abstract methods of
478 // named interfaces using the interface type
479 // (not the named type) as the receiver.
480 // Don't print it in full.
481 buf.WriteString("interface")
483 WriteType(buf, recv.Type(), qf)
487 } else if f.pkg != nil {
488 writePackage(buf, f.pkg, qf)
491 buf.WriteString(f.name)