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"
17 // An Object describes a named language entity such as a package,
18 // constant, type, variable, function (incl. methods), or label.
19 // All objects implement the Object interface.
21 type Object interface {
22 Parent() *Scope // scope in which this object is declared; nil for methods and struct fields
23 Pos() syntax.Pos // position of object identifier in declaration
24 Pkg() *Package // package to which this object belongs; nil for labels and objects in the Universe scope
25 Name() string // package local object name
26 Type() Type // object type
27 Exported() bool // reports whether the name starts with a capital letter
28 Id() string // object name if exported, qualified name if not exported (see func Id)
30 // String returns a human-readable string of the object.
33 // order reflects a package-level object's source order: if object
34 // a is before object b in the source, then a.order() < b.order().
35 // order returns a value > 0 for package-level objects; it returns
36 // 0 for all other objects (including objects in file scopes).
39 // color returns the object's color.
42 // setType sets the type of the object.
45 // setOrder sets the order number of the object. It must be > 0.
48 // setColor sets the object's color. It must not be white.
51 // setParent sets the parent scope of the object.
54 // sameId reports whether obj.Id() and Id(pkg, name) are the same.
55 sameId(pkg *Package, name string) bool
57 // scopePos returns the start position of the scope of this Object
60 // setScopePos sets the start position of the scope for this Object.
61 setScopePos(pos syntax.Pos)
64 func isExported(name string) bool {
65 ch, _ := utf8.DecodeRuneInString(name)
66 return unicode.IsUpper(ch)
69 // Id returns name if it is exported, otherwise it
70 // returns the name qualified with the package path.
71 func Id(pkg *Package, name string) string {
75 // unexported names need the package path for differentiation
76 // (if there's no package, make sure we don't start with '.'
77 // as that may change the order of methods between a setup
78 // inside a package and outside a package - which breaks some
81 // pkg is nil for objects in Universe scope and possibly types
82 // introduced via Eval (see also comment in object.sameId)
83 if pkg != nil && pkg.path != "" {
86 return path + "." + name
89 // An object implements the common parts of an Object.
101 // color encodes the color of an object (see Checker.objDecl for details).
104 // An object may be painted in one of three colors.
105 // Color values other than white or black are considered grey.
109 grey // must be > white and black
112 func (c color) String() string {
123 // colorFor returns the (initial) color for an object depending on
124 // whether its type t is known or not.
125 func colorFor(t Type) color {
132 // Parent returns the scope in which the object is declared.
133 // The result is nil for methods and struct fields.
134 func (obj *object) Parent() *Scope { return obj.parent }
136 // Pos returns the declaration position of the object's identifier.
137 func (obj *object) Pos() syntax.Pos { return obj.pos }
139 // Pkg returns the package to which the object belongs.
140 // The result is nil for labels and objects in the Universe scope.
141 func (obj *object) Pkg() *Package { return obj.pkg }
143 // Name returns the object's (package-local, unqualified) name.
144 func (obj *object) Name() string { return obj.name }
146 // Type returns the object's type.
147 func (obj *object) Type() Type { return obj.typ }
149 // Exported reports whether the object is exported (starts with a capital letter).
150 // It doesn't take into account whether the object is in a local (function) scope
152 func (obj *object) Exported() bool { return isExported(obj.name) }
154 // Id is a wrapper for Id(obj.Pkg(), obj.Name()).
155 func (obj *object) Id() string { return Id(obj.pkg, obj.name) }
157 func (obj *object) String() string { panic("abstract") }
158 func (obj *object) order() uint32 { return obj.order_ }
159 func (obj *object) color() color { return obj.color_ }
160 func (obj *object) scopePos() syntax.Pos { return obj.scopePos_ }
162 func (obj *object) setParent(parent *Scope) { obj.parent = parent }
163 func (obj *object) setType(typ Type) { obj.typ = typ }
164 func (obj *object) setOrder(order uint32) { assert(order > 0); obj.order_ = order }
165 func (obj *object) setColor(color color) { assert(color != white); obj.color_ = color }
166 func (obj *object) setScopePos(pos syntax.Pos) { obj.scopePos_ = pos }
168 func (obj *object) sameId(pkg *Package, name string) bool {
170 // "Two identifiers are different if they are spelled differently,
171 // or if they appear in different packages and are not exported.
172 // Otherwise, they are the same."
173 if name != obj.name {
180 // not exported, so packages must be the same (pkg == nil for
181 // fields in Universe scope; this can only happen for types
182 // introduced via Eval)
183 if pkg == nil || obj.pkg == nil {
184 return pkg == obj.pkg
186 // pkg != nil && obj.pkg != nil
187 return pkg.path == obj.pkg.path
190 // A PkgName represents an imported Go package.
191 // PkgNames don't have a type.
192 type PkgName struct {
195 used bool // set if the package was used
198 // NewPkgName returns a new PkgName object representing an imported package.
199 // The remaining arguments set the attributes found with all Objects.
200 func NewPkgName(pos syntax.Pos, pkg *Package, name string, imported *Package) *PkgName {
201 return &PkgName{object{nil, pos, pkg, name, Typ[Invalid], 0, black, nopos}, imported, false}
204 // Imported returns the package that was imported.
205 // It is distinct from Pkg(), which is the package containing the import statement.
206 func (obj *PkgName) Imported() *Package { return obj.imported }
208 // A Const represents a declared constant.
214 // NewConst returns a new constant with value val.
215 // The remaining arguments set the attributes found with all Objects.
216 func NewConst(pos syntax.Pos, pkg *Package, name string, typ Type, val constant.Value) *Const {
217 return &Const{object{nil, pos, pkg, name, typ, 0, colorFor(typ), nopos}, val}
220 // Val returns the constant's value.
221 func (obj *Const) Val() constant.Value { return obj.val }
223 func (*Const) isDependency() {} // a constant may be a dependency of an initialization expression
225 // A TypeName represents a name for a (defined or alias) type.
226 type TypeName struct {
230 // NewTypeName returns a new type name denoting the given typ.
231 // The remaining arguments set the attributes found with all Objects.
233 // The typ argument may be a defined (Named) type or an alias type.
234 // It may also be nil such that the returned TypeName can be used as
235 // argument for NewNamed, which will set the TypeName's type as a side-
237 func NewTypeName(pos syntax.Pos, pkg *Package, name string, typ Type) *TypeName {
238 return &TypeName{object{nil, pos, pkg, name, typ, 0, colorFor(typ), nopos}}
241 // IsAlias reports whether obj is an alias name for a type.
242 func (obj *TypeName) IsAlias() bool {
243 switch t := obj.typ.(type) {
247 // unsafe.Pointer is not an alias.
248 if obj.pkg == Unsafe {
251 // Any user-defined type name for a basic type is an alias for a
252 // basic type (because basic types are pre-declared in the Universe
253 // scope, outside any package scope), and so is any type name with
254 // a different name than the name of the basic type it refers to.
255 // Additionally, we need to look for "byte" and "rune" because they
256 // are aliases but have the same names (for better error messages).
257 return obj.pkg != nil || t.name != obj.name || t == universeByte || t == universeRune
265 // A Variable represents a declared variable (including function parameters and results, and struct fields).
268 embedded bool // if set, the variable is an embedded struct field, and name is the type name
269 isField bool // var is struct field
270 used bool // set if the variable was used
273 // NewVar returns a new variable.
274 // The arguments set the attributes found with all Objects.
275 func NewVar(pos syntax.Pos, pkg *Package, name string, typ Type) *Var {
276 return &Var{object: object{nil, pos, pkg, name, typ, 0, colorFor(typ), nopos}}
279 // NewParam returns a new variable representing a function parameter.
280 func NewParam(pos syntax.Pos, pkg *Package, name string, typ Type) *Var {
281 return &Var{object: object{nil, pos, pkg, name, typ, 0, colorFor(typ), nopos}, used: true} // parameters are always 'used'
284 // NewField returns a new variable representing a struct field.
285 // For embedded fields, the name is the unqualified type name
286 /// under which the field is accessible.
287 func NewField(pos syntax.Pos, pkg *Package, name string, typ Type, embedded bool) *Var {
288 return &Var{object: object{nil, pos, pkg, name, typ, 0, colorFor(typ), nopos}, embedded: embedded, isField: true}
291 // Anonymous reports whether the variable is an embedded field.
292 // Same as Embedded; only present for backward-compatibility.
293 func (obj *Var) Anonymous() bool { return obj.embedded }
295 // Embedded reports whether the variable is an embedded field.
296 func (obj *Var) Embedded() bool { return obj.embedded }
298 // IsField reports whether the variable is a struct field.
299 func (obj *Var) IsField() bool { return obj.isField }
301 func (*Var) isDependency() {} // a variable may be a dependency of an initialization expression
303 // A Func represents a declared function, concrete method, or abstract
304 // (interface) method. Its Type() is always a *Signature.
305 // An abstract method may belong to many interfaces due to embedding.
308 hasPtrRecv bool // only valid for methods that don't have a type yet
311 // NewFunc returns a new function with the given signature, representing
312 // the function's type.
313 func NewFunc(pos syntax.Pos, pkg *Package, name string, sig *Signature) *Func {
314 // don't store a (typed) nil signature
319 return &Func{object{nil, pos, pkg, name, typ, 0, colorFor(typ), nopos}, false}
322 // FullName returns the package- or receiver-type-qualified name of
323 // function or method obj.
324 func (obj *Func) FullName() string {
326 writeFuncName(&buf, obj, nil)
330 // Scope returns the scope of the function's body block.
331 func (obj *Func) Scope() *Scope { return obj.typ.(*Signature).scope }
333 func (*Func) isDependency() {} // a function may be a dependency of an initialization expression
335 // A Label represents a declared label.
336 // Labels don't have a type.
339 used bool // set if the label was used
342 // NewLabel returns a new label.
343 func NewLabel(pos syntax.Pos, pkg *Package, name string) *Label {
344 return &Label{object{pos: pos, pkg: pkg, name: name, typ: Typ[Invalid], color_: black}, false}
347 // A Builtin represents a built-in function.
348 // Builtins don't have a valid type.
349 type Builtin struct {
354 func newBuiltin(id builtinId) *Builtin {
355 return &Builtin{object{name: predeclaredFuncs[id].name, typ: Typ[Invalid], color_: black}, id}
358 // Nil represents the predeclared value nil.
363 func writeObject(buf *bytes.Buffer, obj Object, qf Qualifier) {
367 switch obj := obj.(type) {
369 fmt.Fprintf(buf, "package %s", obj.Name())
370 if path := obj.imported.path; path != "" && path != obj.name {
371 fmt.Fprintf(buf, " (%q)", path)
376 buf.WriteString("const")
380 buf.WriteString("type")
384 buf.WriteString("field")
386 buf.WriteString("var")
390 buf.WriteString("func ")
391 writeFuncName(buf, obj, qf)
393 WriteSignature(buf, typ.(*Signature), qf)
398 buf.WriteString("label")
402 buf.WriteString("builtin")
406 buf.WriteString("nil")
410 panic(fmt.Sprintf("writeObject(%T)", obj))
415 // For package-level objects, qualify the name.
416 if obj.Pkg() != nil && obj.Pkg().scope.Lookup(obj.Name()) == obj {
417 writePackage(buf, obj.Pkg(), qf)
419 buf.WriteString(obj.Name())
426 // We have a type object: Don't print anything more for
427 // basic types since there's no more information (names
428 // are the same; see also comment in TypeName.IsAlias).
429 if _, ok := typ.(*Basic); ok {
433 buf.WriteString(" =")
440 WriteType(buf, typ, qf)
443 func writePackage(buf *bytes.Buffer, pkg *Package, qf Qualifier) {
459 // ObjectString returns the string form of obj.
460 // The Qualifier controls the printing of
461 // package-level objects, and may be nil.
462 func ObjectString(obj Object, qf Qualifier) string {
464 writeObject(&buf, obj, qf)
468 func (obj *PkgName) String() string { return ObjectString(obj, nil) }
469 func (obj *Const) String() string { return ObjectString(obj, nil) }
470 func (obj *TypeName) String() string { return ObjectString(obj, nil) }
471 func (obj *Var) String() string { return ObjectString(obj, nil) }
472 func (obj *Func) String() string { return ObjectString(obj, nil) }
473 func (obj *Label) String() string { return ObjectString(obj, nil) }
474 func (obj *Builtin) String() string { return ObjectString(obj, nil) }
475 func (obj *Nil) String() string { return ObjectString(obj, nil) }
477 func writeFuncName(buf *bytes.Buffer, f *Func, qf Qualifier) {
479 sig := f.typ.(*Signature)
480 if recv := sig.Recv(); recv != nil {
482 if _, ok := recv.Type().(*Interface); ok {
483 // gcimporter creates abstract methods of
484 // named interfaces using the interface type
485 // (not the named type) as the receiver.
486 // Don't print it in full.
487 buf.WriteString("interface")
489 WriteType(buf, recv.Type(), qf)
493 } else if f.pkg != nil {
494 writePackage(buf, f.pkg, qf)
497 buf.WriteString(f.name)