go types 源码
golang types 代码
文件路径：/src/cmd/compile/internal/noder/types.go
// Copyright 2021 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.
package noder
import (
"cmd/compile/internal/base"
"cmd/compile/internal/ir"
"cmd/compile/internal/typecheck"
"cmd/compile/internal/types"
"cmd/compile/internal/types2"
"cmd/internal/src"
"strings"
)
func (g *irgen) pkg(pkg *types2.Package) *types.Pkg {
switch pkg {
case nil:
return types.BuiltinPkg
case g.self:
return types.LocalPkg
case types2.Unsafe:
return types.UnsafePkg
}
return types.NewPkg(pkg.Path(), pkg.Name())
}
var universeAny = types2.Universe.Lookup("any").Type()
// typ converts a types2.Type to a types.Type, including caching of previously
// translated types.
func (g *irgen) typ(typ types2.Type) *types.Type {
// Defer the CheckSize calls until we have fully-defined a
// (possibly-recursive) top-level type.
types.DeferCheckSize()
res := g.typ1(typ)
types.ResumeCheckSize()
// Finish up any types on typesToFinalize, now that we are at the top of a
// fully-defined (possibly recursive) type. fillinMethods could create more
// types to finalize.
for len(g.typesToFinalize) > 0 {
l := len(g.typesToFinalize)
info := g.typesToFinalize[l-1]
g.typesToFinalize = g.typesToFinalize[:l-1]
types.DeferCheckSize()
g.fillinMethods(info.typ, info.ntyp)
types.ResumeCheckSize()
}
return res
}
// typ1 is like typ, but doesn't call CheckSize, since it may have only
// constructed part of a recursive type. Should not be called from outside this
// file (g.typ is the "external" entry point).
func (g *irgen) typ1(typ types2.Type) *types.Type {
// See issue 49583: the type checker has trouble keeping track of aliases,
// but for such a common alias as any we can improve things by preserving a
// pointer identity that can be checked when formatting type strings.
if typ == universeAny {
return types.AnyType
}
// Cache type2-to-type mappings. Important so that each defined generic
// type (instantiated or not) has a single types.Type representation.
// Also saves a lot of computation and memory by avoiding re-translating
// types2 types repeatedly.
res, ok := g.typs[typ]
if !ok {
res = g.typ0(typ)
// Calculate the size for all concrete types seen by the frontend.
// This is the replacement for the CheckSize() calls in the types1
// typechecker. These will be deferred until the top-level g.typ().
if res != nil && !res.IsUntyped() && !res.IsFuncArgStruct() && !res.HasTParam() {
types.CheckSize(res)
}
g.typs[typ] = res
}
return res
}
// instTypeName2 creates a name for an instantiated type, base on the type args
// (given as types2 types).
func (g *irgen) instTypeName2(name string, targs *types2.TypeList) string {
rparams := make([]*types.Type, targs.Len())
for i := range rparams {
rparams[i] = g.typ(targs.At(i))
}
return typecheck.InstTypeName(name, rparams)
}
// typ0 converts a types2.Type to a types.Type, but doesn't do the caching check
// at the top level.
func (g *irgen) typ0(typ types2.Type) *types.Type {
switch typ := typ.(type) {
case *types2.Basic:
return g.basic(typ)
case *types2.Named:
// If tparams is set, but targs is not, typ is a base generic
// type. typ is appearing as part of the source type of an alias,
// since that is the only use of a generic type that doesn't
// involve instantiation. We just translate the named type in the
// normal way below using g.obj().
if typ.TypeParams() != nil && typ.TypeArgs() != nil {
// typ is an instantiation of a defined (named) generic type.
// This instantiation should also be a defined (named) type.
// types2 gives us the substituted type in t.Underlying()
// The substituted type may or may not still have type
// params. We might, for example, be substituting one type
// param for another type param.
//
// When converted to types.Type, typ has a unique name,
// based on the names of the type arguments.
instName := g.instTypeName2(typ.Obj().Name(), typ.TypeArgs())
s := g.pkg(typ.Obj().Pkg()).Lookup(instName)
// Make sure the base generic type exists in type1 (it may
// not yet if we are referecing an imported generic type, as
// opposed to a generic type declared in this package). Make
// sure to do this lookup before checking s.Def, in case
// s.Def gets defined while importing base (if an imported
// type). (Issue #50486).
base := g.obj(typ.Origin().Obj())
if s.Def != nil {
// We have already encountered this instantiation.
// Use the type we previously created, since there
// must be exactly one instance of a defined type.
return s.Def.Type()
}
if base.Class == ir.PAUTO {
// If the base type is a local type, we want to pop
// this instantiated type symbol/definition when we
// leave the containing block, so we don't use it
// incorrectly later.
types.Pushdcl(s)
}
// Create a forwarding type first and put it in the g.typs
// map, in order to deal with recursive generic types
// (including via method signatures). Set up the extra
// ntyp information (Def, RParams, which may set
// HasTParam) before translating the underlying type
// itself, so we handle recursion correctly.
ntyp := typecheck.NewIncompleteNamedType(g.pos(typ.Obj().Pos()), s)
g.typs[typ] = ntyp
// If ntyp still has type params, then we must be
// referencing something like 'value[T2]', as when
// specifying the generic receiver of a method, where
// value was defined as "type value[T any] ...". Save the
// type args, which will now be the new typeparams of the
// current type.
//
// If ntyp does not have type params, we are saving the
// non-generic types used to instantiate this type. We'll
// use these when instantiating the methods of the
// instantiated type.
targs := typ.TypeArgs()
rparams := make([]*types.Type, targs.Len())
for i := range rparams {
rparams[i] = g.typ1(targs.At(i))
}
ntyp.SetRParams(rparams)
//fmt.Printf("Saw new type %v %v\n", instName, ntyp.HasTParam())
// Save the symbol for the base generic type.
ntyp.SetOrigType(base.Type())
ntyp.SetUnderlying(g.typ1(typ.Underlying()))
if typ.NumMethods() != 0 {
// Save a delayed call to g.fillinMethods() (once
// potentially recursive types have been fully
// resolved).
g.typesToFinalize = append(g.typesToFinalize,
&typeDelayInfo{
typ: typ,
ntyp: ntyp,
})
}
return ntyp
}
obj := g.obj(typ.Obj())
if obj.Op() != ir.OTYPE {
base.FatalfAt(obj.Pos(), "expected type: %L", obj)
}
return obj.Type()
case *types2.Array:
return types.NewArray(g.typ1(typ.Elem()), typ.Len())
case *types2.Chan:
return types.NewChan(g.typ1(typ.Elem()), dirs[typ.Dir()])
case *types2.Map:
return types.NewMap(g.typ1(typ.Key()), g.typ1(typ.Elem()))
case *types2.Pointer:
return types.NewPtr(g.typ1(typ.Elem()))
case *types2.Signature:
return g.signature(nil, typ)
case *types2.Slice:
return types.NewSlice(g.typ1(typ.Elem()))
case *types2.Struct:
fields := make([]*types.Field, typ.NumFields())
for i := range fields {
v := typ.Field(i)
f := types.NewField(g.pos(v), g.selector(v), g.typ1(v.Type()))
f.Note = typ.Tag(i)
if v.Embedded() {
f.Embedded = 1
}
fields[i] = f
}
return types.NewStruct(g.tpkg(typ), fields)
case *types2.Interface:
embeddeds := make([]*types.Field, typ.NumEmbeddeds())
j := 0
for i := range embeddeds {
// TODO(mdempsky): Get embedding position.
e := typ.EmbeddedType(i)
// With Go 1.18, an embedded element can be any type, not
// just an interface.
embeddeds[j] = types.NewField(src.NoXPos, nil, g.typ1(e))
j++
}
embeddeds = embeddeds[:j]
methods := make([]*types.Field, typ.NumExplicitMethods())
for i := range methods {
m := typ.ExplicitMethod(i)
mtyp := g.signature(types.FakeRecv(), m.Type().(*types2.Signature))
methods[i] = types.NewField(g.pos(m), g.selector(m), mtyp)
}
return types.NewInterface(g.tpkg(typ), append(embeddeds, methods...), typ.IsImplicit())
case *types2.TypeParam:
// Save the name of the type parameter in the sym of the type.
// Include the types2 subscript in the sym name
pkg := g.tpkg(typ)
// Create the unique types1 name for a type param, using its context
// with a function, type, or method declaration. Also, map blank type
// param names to a unique name based on their type param index. The
// unique blank names will be exported, but will be reverted during
// types2 and gcimporter import.
assert(g.curDecl != "")
nm := typecheck.TparamExportName(g.curDecl, typ.Obj().Name(), typ.Index())
sym := pkg.Lookup(nm)
if sym.Def != nil {
// Make sure we use the same type param type for the same
// name, whether it is created during types1-import or
// this types2-to-types1 translation.
return sym.Def.Type()
}
obj := ir.NewDeclNameAt(g.pos(typ.Obj().Pos()), ir.OTYPE, sym)
sym.Def = obj
tp := types.NewTypeParam(obj, typ.Index())
obj.SetType(tp)
// Set g.typs[typ] in case the bound methods reference typ.
g.typs[typ] = tp
bound := g.typ1(typ.Constraint())
tp.SetBound(bound)
return tp
case *types2.Union:
nt := typ.Len()
tlist := make([]*types.Type, nt)
tildes := make([]bool, nt)
for i := range tlist {
t := typ.Term(i)
tlist[i] = g.typ1(t.Type())
tildes[i] = t.Tilde()
}
return types.NewUnion(tlist, tildes)
case *types2.Tuple:
// Tuples are used for the type of a function call (i.e. the
// return value of the function).
if typ == nil {
return (*types.Type)(nil)
}
fields := make([]*types.Field, typ.Len())
for i := range fields {
fields[i] = g.param(typ.At(i))
}
t := types.NewStruct(types.LocalPkg, fields)
t.StructType().Funarg = types.FunargResults
return t
default:
base.FatalfAt(src.NoXPos, "unhandled type: %v (%T)", typ, typ)
panic("unreachable")
}
}
// fillinMethods fills in the method name nodes and types for a defined type with at
// least one method. This is needed for later typechecking when looking up methods of
// instantiated types, and for actually generating the methods for instantiated
// types.
func (g *irgen) fillinMethods(typ *types2.Named, ntyp *types.Type) {
targs2 := typ.TypeArgs()
targs := make([]*types.Type, targs2.Len())
for i := range targs {
targs[i] = g.typ1(targs2.At(i))
}
methods := make([]*types.Field, typ.NumMethods())
for i := range methods {
m := typ.Method(i)
recvType := deref2(types2.AsSignature(m.Type()).Recv().Type())
var meth *ir.Name
imported := false
if m.Pkg() != g.self {
// Imported methods cannot be loaded by name (what
// g.obj() does) - they must be loaded via their
// type.
meth = g.obj(recvType.(*types2.Named).Obj()).Type().Methods().Index(i).Nname.(*ir.Name)
// XXX Because Obj() returns the object of the base generic
// type, we have to still do the method translation below.
imported = true
} else {
meth = g.obj(m)
}
assert(recvType == types2.Type(typ))
if imported {
// Unfortunately, meth is the type of the method of the
// generic type, so we have to do a substitution to get
// the name/type of the method of the instantiated type,
// using m.Type().RParams() and typ.TArgs()
inst2 := g.instTypeName2("", typ.TypeArgs())
name := meth.Sym().Name
i1 := strings.Index(name, "[")
i2 := strings.Index(name[i1:], "]")
assert(i1 >= 0 && i2 >= 0)
// Generate the name of the instantiated method.
name = name[0:i1] + inst2 + name[i1+i2+1:]
newsym := meth.Sym().Pkg.Lookup(name)
var meth2 *ir.Name
if newsym.Def != nil {
meth2 = newsym.Def.(*ir.Name)
} else {
meth2 = ir.NewNameAt(meth.Pos(), newsym)
rparams := types2.AsSignature(m.Type()).RecvTypeParams()
tparams := make([]*types.Type, rparams.Len())
// Set g.curDecl to be the method context, so type
// params in the receiver of the method that we are
// translating gets the right unique name. We could
// be in a top-level typeDecl, so save and restore
// the current contents of g.curDecl.
savedCurDecl := g.curDecl
g.curDecl = typ.Obj().Name() + "." + m.Name()
for i := range tparams {
tparams[i] = g.typ1(rparams.At(i))
}
g.curDecl = savedCurDecl
assert(len(tparams) == len(targs))
ts := typecheck.Tsubster{
Tparams: tparams,
Targs: targs,
}
// Do the substitution of the type
meth2.SetType(ts.Typ(meth.Type()))
newsym.Def = meth2
}
meth = meth2
}
methods[i] = types.NewField(meth.Pos(), g.selector(m), meth.Type())
methods[i].Nname = meth
}
ntyp.Methods().Set(methods)
if !ntyp.HasTParam() && !ntyp.HasShape() {
// Generate all the methods for a new fully-instantiated type.
typecheck.NeedInstType(ntyp)
}
}
func (g *irgen) signature(recv *types.Field, sig *types2.Signature) *types.Type {
tparams2 := sig.TypeParams()
tparams := make([]*types.Field, tparams2.Len())
for i := range tparams {
tp := tparams2.At(i).Obj()
tparams[i] = types.NewField(g.pos(tp), g.sym(tp), g.typ1(tp.Type()))
}
do := func(typ *types2.Tuple) []*types.Field {
fields := make([]*types.Field, typ.Len())
for i := range fields {
fields[i] = g.param(typ.At(i))
}
return fields
}
params := do(sig.Params())
results := do(sig.Results())
if sig.Variadic() {
params[len(params)-1].SetIsDDD(true)
}
return types.NewSignature(g.tpkg(sig), recv, tparams, params, results)
}
func (g *irgen) param(v *types2.Var) *types.Field {
return types.NewField(g.pos(v), g.sym(v), g.typ1(v.Type()))
}
func (g *irgen) sym(obj types2.Object) *types.Sym {
if name := obj.Name(); name != "" {
return g.pkg(obj.Pkg()).Lookup(obj.Name())
}
return nil
}
func (g *irgen) selector(obj types2.Object) *types.Sym {
pkg, name := g.pkg(obj.Pkg()), obj.Name()
if types.IsExported(name) {
pkg = types.LocalPkg
}
return pkg.Lookup(name)
}
// tpkg returns the package that a function, interface, struct, or typeparam type
// expression appeared in.
//
// Caveat: For the degenerate types "func()", "interface{}", and
// "struct{}", tpkg always returns LocalPkg. However, we only need the
// package information so that go/types can report it via its API, and
// the reason we fail to return the original package for these
// particular types is because go/types does *not* report it for
// them. So in practice this limitation is probably moot.
func (g *irgen) tpkg(typ types2.Type) *types.Pkg {
if obj := anyObj(typ); obj != nil {
return g.pkg(obj.Pkg())
}
return types.LocalPkg
}
// anyObj returns some object accessible from typ, if any.
func anyObj(typ types2.Type) types2.Object {
switch typ := typ.(type) {
case *types2.Signature:
if recv := typ.Recv(); recv != nil {
return recv
}
if params := typ.Params(); params.Len() > 0 {
return params.At(0)
}
if results := typ.Results(); results.Len() > 0 {
return results.At(0)
}
case *types2.Struct:
if typ.NumFields() > 0 {
return typ.Field(0)
}
case *types2.Interface:
if typ.NumExplicitMethods() > 0 {
return typ.ExplicitMethod(0)
}
case *types2.TypeParam:
return typ.Obj()
}
return nil
}
func (g *irgen) basic(typ *types2.Basic) *types.Type {
switch typ.Name() {
case "byte":
return types.ByteType
case "rune":
return types.RuneType
}
return *basics[typ.Kind()]
}
var basics = [...]**types.Type{
types2.Invalid: new(*types.Type),
types2.Bool: &types.Types[types.TBOOL],
types2.Int: &types.Types[types.TINT],
types2.Int8: &types.Types[types.TINT8],
types2.Int16: &types.Types[types.TINT16],
types2.Int32: &types.Types[types.TINT32],
types2.Int64: &types.Types[types.TINT64],
types2.Uint: &types.Types[types.TUINT],
types2.Uint8: &types.Types[types.TUINT8],
types2.Uint16: &types.Types[types.TUINT16],
types2.Uint32: &types.Types[types.TUINT32],
types2.Uint64: &types.Types[types.TUINT64],
types2.Uintptr: &types.Types[types.TUINTPTR],
types2.Float32: &types.Types[types.TFLOAT32],
types2.Float64: &types.Types[types.TFLOAT64],
types2.Complex64: &types.Types[types.TCOMPLEX64],
types2.Complex128: &types.Types[types.TCOMPLEX128],
types2.String: &types.Types[types.TSTRING],
types2.UnsafePointer: &types.Types[types.TUNSAFEPTR],
types2.UntypedBool: &types.UntypedBool,
types2.UntypedInt: &types.UntypedInt,
types2.UntypedRune: &types.UntypedRune,
types2.UntypedFloat: &types.UntypedFloat,
types2.UntypedComplex: &types.UntypedComplex,
types2.UntypedString: &types.UntypedString,
types2.UntypedNil: &types.Types[types.TNIL],
}
var dirs = [...]types.ChanDir{
types2.SendRecv: types.Cboth,
types2.SendOnly: types.Csend,
types2.RecvOnly: types.Crecv,
}
// deref2 does a single deref of types2 type t, if it is a pointer type.
func deref2(t types2.Type) types2.Type {
if ptr := types2.AsPointer(t); ptr != nil {
t = ptr.Elem()
}
return t
}
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