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go/types, types2: store Named instance information separately

Browse source 
Separate instance information into an instance struct, to reduce memory
footprint for non-instance Named types. This may induce a sense of
deja-vu: we had a similar construct in the past that was removed as
unnecessary. With additional new fields being added that only apply to
instances, having a separate struct makes sense again.

Updates #52728

Change-Id: I0bb5982d71c27e6b574bfb4f7b886a6aeb9c5390
Reviewed-on: https://go-review.googlesource.com/c/go/+/404884
Reviewed-by: Robert Griesemer <gri@google.com>
Run-TryBot: Robert Findley <rfindley@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
This commit is contained in:
Robert Findley 2022-05-07 19:26:35 -04:00
parent 1323b0e8f0
commit 02e69cfa96
22 changed files with 222 additions and 154 deletions
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4
src/cmd/compile/internal/types2/decl.go
View file

@ -508,7 +508,7 @@ func (check *Checker) typeDecl(obj *TypeName, tdecl *syntax.TypeDecl, def *Named
}
// type definition or generic type declaration
named := check.newNamed(obj, nil, nil, nil)
named := check.newNamed(obj, nil, nil)
def.setUnderlying(named)
if tdecl.TParamList != nil {
@ -635,7 +635,7 @@ func (check *Checker) collectMethods(obj *TypeName) {
// and field names must be distinct."
base, _ := obj.typ.(*Named) // shouldn't fail but be conservative
if base != nil {
assert(base.targs.Len() == 0) // collectMethods should not be called on an instantiated type
assert(base.TypeArgs().Len() == 0) // collectMethods should not be called on an instantiated type
// See issue #52529: we must delay the expansion of underlying here, as
// base may not be fully set-up.

2
src/cmd/compile/internal/types2/infer.go
View file

@ -434,7 +434,7 @@ func (w *tpWalker) isParameterized(typ Type) (res bool) {
return w.isParameterized(t.elem)
case *Named:
return w.isParameterizedTypeList(t.targs.list())
return w.isParameterizedTypeList(t.TypeArgs().list())
case *TypeParam:
// t must be one of w.tparams

5
src/cmd/compile/internal/types2/instantiate.go
View file

@ -76,10 +76,7 @@ func (check *Checker) instance(pos syntax.Pos, orig Type, targs []Type, ctxt *Co
switch orig := orig.(type) {
case *Named:
tname := NewTypeName(pos, orig.obj.pkg, orig.obj.name, nil)
named := check.newNamed(tname, orig, nil, nil) // underlying, tparams, and methods are set when named is resolved
named.targs = newTypeList(targs)
res = named
res = check.newNamedInstance(pos, orig, targs)
case *Signature:
tparams := orig.TypeParams()

131
src/cmd/compile/internal/types2/named.go
View file

@ -5,6 +5,7 @@
package types2
import (
"cmd/compile/internal/syntax"
"sync"
"sync/atomic"
)
@ -83,14 +84,15 @@ import (
type Named struct {
check *Checker // non-nil during type-checking; nil otherwise
obj *TypeName // corresponding declared object for declared types; see above for instantiated types
orig *Named // origin type for instantiated types, this type for declared types
targs *TypeList // type arguments (after instantiation), or nil
// fromRHS holds the type (on RHS of declaration) this *Named type is derived
// from (for cycle reporting). Only used by validType, and therefore does not
// require synchronization.
fromRHS Type
// information for instantiated types; nil otherwise
inst *instance
mu sync.Mutex // guards all fields below
state_ uint32 // the current state of this type; must only be accessed atomically
underlying Type // possibly a *Named during setup; never a *Named once set up completely
@ -102,13 +104,19 @@ type Named struct {
// instantiated types, methods are individually expanded when they are first
// accessed.
methods []*Func
// number of expanded methods (only valid for instantiated named types)
expandedMethods int // expandedMethods <= len(orig.methods)
// loader may be provided to lazily load type parameters, underlying type, and methods.
loader func(*Named) (tparams []*TypeParam, underlying Type, methods []*Func)
}
// instance holds information that is only necessary for instantiated named
// types.
type instance struct {
orig *Named // original, uninstantiated type
targs *TypeList // type arguments
expandedMethods int // number of expanded methods; expandedMethods <= len(orig.methods)
}
// namedState represents the possible states that a named type may assume.
type namedState uint32
@ -125,7 +133,7 @@ func NewNamed(obj *TypeName, underlying Type, methods []*Func) *Named {
if _, ok := underlying.(*Named); ok {
panic("underlying type must not be *Named")
}
return (*Checker)(nil).newNamed(obj, nil, underlying, methods)
return (*Checker)(nil).newNamed(obj, underlying, methods)
}
// resolve resolves the type parameters, methods, and underlying type of n.
@ -149,19 +157,20 @@ func (n *Named) resolve(ctxt *Context) *Named {
return n
}
if n.TypeArgs().Len() > 0 {
if n.inst != nil {
assert(n.underlying == nil) // n is an unresolved instance
assert(n.loader == nil) // instances are created by instantiation, in which case n.loader is nil
n.orig.resolve(ctxt)
orig := n.inst.orig
orig.resolve(ctxt)
underlying := n.expandUnderlying(ctxt)
n.tparams = n.orig.tparams
n.tparams = orig.tparams
n.underlying = underlying
n.fromRHS = n.orig.fromRHS // for cycle detection
n.fromRHS = orig.fromRHS // for cycle detection
if len(n.orig.methods) == 0 {
n.setState(complete)
if len(orig.methods) == 0 {
n.setState(complete) // nothing further to do
} else {
n.setState(resolved)
}
@ -204,11 +213,8 @@ func (n *Named) setState(state namedState) {
}
// newNamed is like NewNamed but with a *Checker receiver and additional orig argument.
func (check *Checker) newNamed(obj *TypeName, orig *Named, underlying Type, methods []*Func) *Named {
typ := &Named{check: check, obj: obj, orig: orig, fromRHS: underlying, underlying: underlying, methods: methods}
if typ.orig == nil {
typ.orig = typ
}
func (check *Checker) newNamed(obj *TypeName, underlying Type, methods []*Func) *Named {
typ := &Named{check: check, obj: obj, fromRHS: underlying, underlying: underlying, methods: methods}
if obj.typ == nil {
obj.typ = typ
}
@ -219,8 +225,22 @@ func (check *Checker) newNamed(obj *TypeName, orig *Named, underlying Type, meth
return typ
}
func (check *Checker) newNamedInstance(pos syntax.Pos, orig *Named, targs []Type) *Named {
assert(len(targs) > 0)
obj := NewTypeName(pos, orig.obj.pkg, orig.obj.name, nil)
inst := &instance{orig: orig, targs: newTypeList(targs)}
typ := &Named{check: check, obj: obj, inst: inst}
obj.typ = typ
// Ensure that typ is always expanded and sanity-checked.
if check != nil {
check.needsCleanup(typ)
}
return typ
}
func (t *Named) cleanup() {
assert(t.orig.orig == t.orig)
assert(t.inst == nil || t.inst.orig.inst == nil)
// Ensure that every defined type created in the course of type-checking has
// either non-*Named underlying type, or is unexpanded.
//
@ -242,14 +262,21 @@ func (t *Named) cleanup() {
// Obj returns the type name for the declaration defining the named type t. For
// instantiated types, this is same as the type name of the origin type.
func (t *Named) Obj() *TypeName { return t.orig.obj } // for non-instances this is the same as t.obj
func (t *Named) Obj() *TypeName {
if t.inst == nil {
return t.obj
}
return t.inst.orig.obj
}
// Origin returns the generic type from which the named type t is
// instantiated. If t is not an instantiated type, the result is t.
func (t *Named) Origin() *Named { return t.orig }
// TODO(gri) Come up with a better representation and API to distinguish
// between parameterized instantiated and non-instantiated types.
func (t *Named) Origin() *Named {
if t.inst == nil {
return t
}
return t.inst.orig
}
// TypeParams returns the type parameters of the named type t, or nil.
// The result is non-nil for an (originally) generic type even if it is instantiated.
@ -258,19 +285,26 @@ func (t *Named) TypeParams() *TypeParamList { return t.resolve(nil).tparams }
// SetTypeParams sets the type parameters of the named type t.
// t must not have type arguments.
func (t *Named) SetTypeParams(tparams []*TypeParam) {
assert(t.targs.Len() == 0)
assert(t.inst == nil)
t.resolve(nil).tparams = bindTParams(tparams)
}
// TypeArgs returns the type arguments used to instantiate the named type t.
func (t *Named) TypeArgs() *TypeList { return t.targs }
func (t *Named) TypeArgs() *TypeList {
if t.inst == nil {
return nil
}
return t.inst.targs
}
// NumMethods returns the number of explicit methods defined for t.
//
// For an ordinary or instantiated type t, the receiver base type of these
// methods will be the named type t. For an uninstantiated generic type t, each
// method receiver will be instantiated with its receiver type parameters.
func (t *Named) NumMethods() int { return len(t.orig.resolve(nil).methods) }
func (t *Named) NumMethods() int {
return len(t.Origin().resolve(nil).methods)
}
// Method returns the i'th method of named type t for 0 <= i < t.NumMethods().
func (t *Named) Method(i int) *Func {
@ -280,23 +314,24 @@ func (t *Named) Method(i int) *Func {
return t.methods[i]
}
assert(t.TypeArgs().Len() > 0) // only instances should have incomplete methods
assert(t.inst != nil) // only instances should have incomplete methods
orig := t.inst.orig
t.mu.Lock()
defer t.mu.Unlock()
if len(t.methods) != len(t.orig.methods) {
if len(t.methods) != len(orig.methods) {
assert(len(t.methods) == 0)
t.methods = make([]*Func, len(t.orig.methods))
t.methods = make([]*Func, len(orig.methods))
}
if t.methods[i] == nil {
t.methods[i] = t.expandMethod(i)
t.expandedMethods++
t.inst.expandedMethods++
// Check if we've created all methods at this point. If we have, mark the
// type as fully expanded.
if t.expandedMethods == len(t.orig.methods) {
if t.inst.expandedMethods == len(orig.methods) {
t.setState(complete)
}
}
@ -307,11 +342,9 @@ func (t *Named) Method(i int) *Func {
// expandMethod substitutes type arguments in the i'th method for an
// instantiated receiver.
func (t *Named) expandMethod(i int) *Func {
assert(t.TypeArgs().Len() > 0) // t must be an instance
// t.orig.methods is not lazy. origm is the method instantiated with its
// receiver type parameters (the "origin" method).
origm := t.orig.Method(i)
origm := t.inst.orig.Method(i)
assert(origm != nil)
check := t.check
@ -338,9 +371,9 @@ func (t *Named) expandMethod(i int) *Func {
// We can only substitute if we have a correspondence between type arguments
// and type parameters. This check is necessary in the presence of invalid
// code.
if origSig.RecvTypeParams().Len() == t.targs.Len() {
if origSig.RecvTypeParams().Len() == t.inst.targs.Len() {
ctxt := check.bestContext(nil)
smap := makeSubstMap(origSig.RecvTypeParams().list(), t.targs.list())
smap := makeSubstMap(origSig.RecvTypeParams().list(), t.inst.targs.list())
sig = check.subst(origm.pos, origSig, smap, ctxt).(*Signature)
}
@ -365,7 +398,7 @@ func (t *Named) expandMethod(i int) *Func {
// SetUnderlying sets the underlying type and marks t as complete.
// t must not have type arguments.
func (t *Named) SetUnderlying(underlying Type) {
assert(t.targs.Len() == 0)
assert(t.inst == nil)
if underlying == nil {
panic("underlying type must not be nil")
}
@ -381,7 +414,7 @@ func (t *Named) SetUnderlying(underlying Type) {
// AddMethod adds method m unless it is already in the method list.
// t must not have type arguments.
func (t *Named) AddMethod(m *Func) {
assert(t.targs.Len() == 0)
assert(t.inst == nil)
t.resolve(nil)
if i, _ := lookupMethod(t.methods, m.pkg, m.name, false); i < 0 {
t.methods = append(t.methods, m)
@ -493,7 +526,7 @@ func (n *Named) lookupMethod(pkg *Package, name string, foldCase bool) (int, *Fu
// If n is an instance, we may not have yet instantiated all of its methods.
// Look up the method index in orig, and only instantiate method at the
// matching index (if any).
i, _ := lookupMethod(n.orig.methods, pkg, name, foldCase)
i, _ := lookupMethod(n.Origin().methods, pkg, name, foldCase)
if i < 0 {
return -1, nil
}
@ -531,36 +564,39 @@ func (n *Named) expandUnderlying(ctxt *Context) Type {
}()
}
assert(n.orig.underlying != nil)
assert(n.inst.orig.underlying != nil)
if _, unexpanded := n.orig.underlying.(*Named); unexpanded {
orig := n.inst.orig
targs := n.inst.targs
if _, unexpanded := orig.underlying.(*Named); unexpanded {
// We should only get a Named underlying type here during type checking
// (for example, in recursive type declarations).
assert(check != nil)
}
if n.orig.tparams.Len() != n.targs.Len() {
if orig.tparams.Len() != targs.Len() {
// Mismatching arg and tparam length may be checked elsewhere.
return Typ[Invalid]
}
// We must always have a context, to avoid infinite recursion.
ctxt = check.bestContext(ctxt)
h := ctxt.instanceHash(n.orig, n.targs.list())
h := ctxt.instanceHash(orig, targs.list())
// ensure that an instance is recorded for h to avoid infinite recursion.
ctxt.update(h, n.orig, n.TypeArgs().list(), n)
ctxt.update(h, orig, targs.list(), n)
smap := makeSubstMap(n.orig.tparams.list(), n.targs.list())
underlying := n.check.subst(n.obj.pos, n.orig.underlying, smap, ctxt)
smap := makeSubstMap(orig.tparams.list(), targs.list())
underlying := n.check.subst(n.obj.pos, orig.underlying, smap, ctxt)
// If the underlying type of n is an interface, we need to set the receiver
// of its methods accurately -- we set the receiver of interface methods on
// the RHS of a type declaration to the defined type.
if iface, _ := underlying.(*Interface); iface != nil {
if methods, copied := replaceRecvType(iface.methods, n.orig, n); copied {
if methods, copied := replaceRecvType(iface.methods, orig, n); copied {
// If the underlying type doesn't actually use type parameters, it's
// possible that it wasn't substituted. In this case we need to create
// a new *Interface before modifying receivers.
if iface == n.orig.underlying {
if iface == orig.underlying {
old := iface
iface = check.newInterface()
iface.embeddeds = old.embeddeds
@ -571,6 +607,7 @@ func (n *Named) expandUnderlying(ctxt *Context) Type {
iface.methods = methods
}
}
return underlying
}

4
src/cmd/compile/internal/types2/predicates.go
View file

@ -102,7 +102,7 @@ func isTypeParam(t Type) bool {
func isGeneric(t Type) bool {
// A parameterized type is only generic if it doesn't have an instantiation already.
named, _ := t.(*Named)
return named != nil && named.obj != nil && named.targs == nil && named.TypeParams() != nil
return named != nil && named.obj != nil && named.inst == nil && named.TypeParams().Len() > 0
}
// Comparable reports whether values of type T are comparable.
@ -401,7 +401,7 @@ func identical(x, y Type, cmpTags bool, p *ifacePair) bool {
if len(xargs) > 0 {
// Instances are identical if their original type and type arguments
// are identical.
if !Identical(x.orig, y.orig) {
if !Identical(x.Origin(), y.Origin()) {
return false
}
for i, xa := range xargs {

2
src/cmd/compile/internal/types2/sizeof_test.go
View file

@ -31,7 +31,7 @@ func TestSizeof(t *testing.T) {
{Interface{}, 40, 80},
{Map{}, 16, 32},
{Chan{}, 12, 24},
{Named{}, 68, 128},
{Named{}, 60, 112},
{TypeParam{}, 28, 48},
{term{}, 12, 24},

25
src/cmd/compile/internal/types2/subst.go
View file

@ -176,7 +176,7 @@ func (subst *subster) typ(typ Type) Type {
// In this case the interface will not be substituted here, because its
// method signatures do not depend on the type parameter P, but we still
// need to create new interface methods to hold the instantiated
// receiver. This is handled by expandNamed.
// receiver. This is handled by Named.expandUnderlying.
iface.methods, _ = replaceRecvType(methods, t, iface)
return iface
}
@ -207,19 +207,20 @@ func (subst *subster) typ(typ Type) Type {
}
}
// subst is called by expandNamed, so in this function we need to be
// subst is called during expansion, so in this function we need to be
// careful not to call any methods that would cause t to be expanded: doing
// so would result in deadlock.
//
// So we call t.orig.TypeParams() rather than t.TypeParams() here and
// below.
if t.orig.TypeParams().Len() == 0 {
// So we call t.Origin().TypeParams() rather than t.TypeParams().
orig := t.Origin()
n := orig.TypeParams().Len()
if n == 0 {
dump(">>> %s is not parameterized", t)
return t // type is not parameterized
}
var newTArgs []Type
if t.targs.Len() != t.orig.TypeParams().Len() {
if t.TypeArgs().Len() != n {
return Typ[Invalid] // error reported elsewhere
}
@ -228,14 +229,14 @@ func (subst *subster) typ(typ Type) Type {
// For each (existing) type argument targ, determine if it needs
// to be substituted; i.e., if it is or contains a type parameter
// that has a type argument for it.
for i, targ := range t.targs.list() {
for i, targ := range t.TypeArgs().list() {
dump(">>> %d targ = %s", i, targ)
new_targ := subst.typ(targ)
if new_targ != targ {
dump(">>> substituted %d targ %s => %s", i, targ, new_targ)
if newTArgs == nil {
newTArgs = make([]Type, t.orig.TypeParams().Len())
copy(newTArgs, t.targs.list())
newTArgs = make([]Type, n)
copy(newTArgs, t.TypeArgs().list())
}
newTArgs[i] = new_targ
}
@ -247,9 +248,9 @@ func (subst *subster) typ(typ Type) Type {
}
// before creating a new named type, check if we have this one already
h := subst.ctxt.instanceHash(t.orig, newTArgs)
h := subst.ctxt.instanceHash(orig, newTArgs)
dump(">>> new type hash: %s", h)
if named := subst.ctxt.lookup(h, t.orig, newTArgs); named != nil {
if named := subst.ctxt.lookup(h, orig, newTArgs); named != nil {
dump(">>> found %s", named)
return named
}
@ -258,7 +259,7 @@ func (subst *subster) typ(typ Type) Type {
// recursion. The position used here is irrelevant because validation only
// occurs on t (we don't call validType on named), but we use subst.pos to
// help with debugging.
return subst.check.instance(subst.pos, t.orig, newTArgs, subst.ctxt)
return subst.check.instance(subst.pos, orig, newTArgs, subst.ctxt)
// Note that if we were to expose substitution more generally (not just in
// the context of a declaration), we'd have to substitute in

4
src/cmd/compile/internal/types2/typestring.go
View file

@ -284,9 +284,9 @@ func (w *typeWriter) typ(typ Type) {
w.string(strconv.Itoa(w.ctxt.getID(t)))
}
w.typeName(t.obj) // when hashing written for readability of the hash only
if t.targs != nil {
if t.inst != nil {
// instantiated type
w.typeList(t.targs.list())
w.typeList(t.inst.targs.list())
} else if w.ctxt == nil && t.TypeParams().Len() != 0 { // For type hashing, don't need to format the TypeParams
// parameterized type
w.tParamList(t.TypeParams().list())

6
src/cmd/compile/internal/types2/typexpr.go
View file

@ -444,8 +444,8 @@ func (check *Checker) instantiatedType(x syntax.Expr, xlist []syntax.Expr, def *
// errors.
check.recordInstance(x, inst.TypeArgs().list(), inst)
if check.validateTArgLen(x.Pos(), inst.TypeParams().Len(), inst.targs.Len()) {
if i, err := check.verify(x.Pos(), inst.TypeParams().list(), inst.targs.list()); err != nil {
if check.validateTArgLen(x.Pos(), inst.TypeParams().Len(), inst.TypeArgs().Len()) {
if i, err := check.verify(x.Pos(), inst.TypeParams().list(), inst.TypeArgs().list()); err != nil {
// best position for error reporting
pos := x.Pos()
if i < len(xlist) {
@ -453,7 +453,7 @@ func (check *Checker) instantiatedType(x syntax.Expr, xlist []syntax.Expr, def *
}
check.softErrorf(pos, "%s", err)
} else {
check.mono.recordInstance(check.pkg, x.Pos(), inst.TypeParams().list(), inst.targs.list(), xlist)
check.mono.recordInstance(check.pkg, x.Pos(), inst.TypeParams().list(), inst.TypeArgs().list(), xlist)
}
}

4
src/cmd/compile/internal/types2/unify.go
View file

@ -546,8 +546,8 @@ func (u *unifier) nify(x, y Type, p *ifacePair) (result bool) {
case *Named:
// TODO(gri) This code differs now from the parallel code in Checker.identical. Investigate.
if y, ok := y.(*Named); ok {
xargs := x.targs.list()
yargs := y.targs.list()
xargs := x.TypeArgs().list()
yargs := y.TypeArgs().list()
if len(xargs) != len(yargs) {
return false

2
src/cmd/compile/internal/types2/validtype.go
View file

@ -72,7 +72,7 @@ func (check *Checker) validType0(typ Type, env *tparamEnv, path []Object) typeIn
switch check.infoMap[t] {
case unknown:
check.infoMap[t] = marked
check.infoMap[t] = check.validType0(t.orig.fromRHS, env.push(t), append(path, t.obj))
check.infoMap[t] = check.validType0(t.Origin().fromRHS, env.push(t), append(path, t.obj))
case marked:
// We have seen type t before and thus must have a cycle.
check.infoMap[t] = invalid

4
src/go/types/decl.go
View file

@ -565,7 +565,7 @@ func (check *Checker) typeDecl(obj *TypeName, tdecl *ast.TypeSpec, def *Named) {
}
// type definition or generic type declaration
named := check.newNamed(obj, nil, nil, nil)
named := check.newNamed(obj, nil, nil)
def.setUnderlying(named)
if tdecl.TypeParams != nil {
@ -711,7 +711,7 @@ func (check *Checker) collectMethods(obj *TypeName) {
// and field names must be distinct."
base, _ := obj.typ.(*Named) // shouldn't fail but be conservative
if base != nil {
assert(base.targs.Len() == 0) // collectMethods should not be called on an instantiated type
assert(base.TypeArgs().Len() == 0) // collectMethods should not be called on an instantiated type
// See issue #52529: we must delay the expansion of underlying here, as
// base may not be fully set-up.

2
src/go/types/infer.go
View file

@ -434,7 +434,7 @@ func (w *tpWalker) isParameterized(typ Type) (res bool) {
return w.isParameterized(t.elem)
case *Named:
return w.isParameterizedTypeList(t.targs.list())
return w.isParameterizedTypeList(t.TypeArgs().list())
case *TypeParam:
// t must be one of w.tparams

5
src/go/types/instantiate.go
View file

@ -76,10 +76,7 @@ func (check *Checker) instance(pos token.Pos, orig Type, targs []Type, ctxt *Con
switch orig := orig.(type) {
case *Named:
tname := NewTypeName(pos, orig.obj.pkg, orig.obj.name, nil)
named := check.newNamed(tname, orig, nil, nil) // underlying, tparams, and methods are set when named is resolved
named.targs = newTypeList(targs)
res = named
res = check.newNamedInstance(pos, orig, targs)
case *Signature:
tparams := orig.TypeParams()

129
src/go/types/named.go
View file

@ -5,6 +5,7 @@
package types
import (
"go/token"
"sync"
"sync/atomic"
)
@ -83,14 +84,15 @@ import (
type Named struct {
check *Checker // non-nil during type-checking; nil otherwise
obj *TypeName // corresponding declared object for declared types; see above for instantiated types
orig *Named // origin type for instantiated types, this type for declared types
targs *TypeList // type arguments (after instantiation), or nil
// fromRHS holds the type (on RHS of declaration) this *Named type is derived
// from (for cycle reporting). Only used by validType, and therefore does not
// require synchronization.
fromRHS Type
// information for instantiated types; nil otherwise
inst *instance
mu sync.Mutex // guards all fields below
state_ uint32 // the current state of this type; must only be accessed atomically
underlying Type // possibly a *Named during setup; never a *Named once set up completely
@ -102,13 +104,19 @@ type Named struct {
// instantiated types, methods are individually expanded when they are first
// accessed.
methods []*Func
// number of expanded methods (only valid for instantiated named types)
expandedMethods int // expandedMethods <= len(orig.methods)
// loader may be provided to lazily load type parameters, underlying type, and methods.
loader func(*Named) (tparams []*TypeParam, underlying Type, methods []*Func)
}
// instance holds information that is only necessary for instantiated named
// types.
type instance struct {
orig *Named // original, uninstantiated type
targs *TypeList // type arguments
expandedMethods int // number of expanded methods; expandedMethods <= len(orig.methods)
}
// namedState represents the possible states that a named type may assume.
type namedState uint32
@ -125,7 +133,7 @@ func NewNamed(obj *TypeName, underlying Type, methods []*Func) *Named {
if _, ok := underlying.(*Named); ok {
panic("underlying type must not be *Named")
}
return (*Checker)(nil).newNamed(obj, nil, underlying, methods)
return (*Checker)(nil).newNamed(obj, underlying, methods)
}
// resolve resolves the type parameters, methods, and underlying type of n.
@ -149,19 +157,20 @@ func (n *Named) resolve(ctxt *Context) *Named {
return n
}
if n.TypeArgs().Len() > 0 {
if n.inst != nil {
assert(n.underlying == nil) // n is an unresolved instance
assert(n.loader == nil) // instances are created by instantiation, in which case n.loader is nil
n.orig.resolve(ctxt)
orig := n.inst.orig
orig.resolve(ctxt)
underlying := n.expandUnderlying(ctxt)
n.tparams = n.orig.tparams
n.tparams = orig.tparams
n.underlying = underlying
n.fromRHS = n.orig.fromRHS // for cycle detection
n.fromRHS = orig.fromRHS // for cycle detection
if len(n.orig.methods) == 0 {
n.setState(complete)
if len(orig.methods) == 0 {
n.setState(complete) // nothing further to do
} else {
n.setState(resolved)
}
@ -204,11 +213,8 @@ func (n *Named) setState(state namedState) {
}
// newNamed is like NewNamed but with a *Checker receiver and additional orig argument.
func (check *Checker) newNamed(obj *TypeName, orig *Named, underlying Type, methods []*Func) *Named {
typ := &Named{check: check, obj: obj, orig: orig, fromRHS: underlying, underlying: underlying, methods: methods}
if typ.orig == nil {
typ.orig = typ
}
func (check *Checker) newNamed(obj *TypeName, underlying Type, methods []*Func) *Named {
typ := &Named{check: check, obj: obj, fromRHS: underlying, underlying: underlying, methods: methods}
if obj.typ == nil {
obj.typ = typ
}
@ -219,8 +225,22 @@ func (check *Checker) newNamed(obj *TypeName, orig *Named, underlying Type, meth
return typ
}
func (check *Checker) newNamedInstance(pos token.Pos, orig *Named, targs []Type) *Named {
assert(len(targs) > 0)
obj := NewTypeName(pos, orig.obj.pkg, orig.obj.name, nil)
inst := &instance{orig: orig, targs: newTypeList(targs)}
typ := &Named{check: check, obj: obj, inst: inst}
obj.typ = typ
// Ensure that typ is always expanded and sanity-checked.
if check != nil {
check.needsCleanup(typ)
}
return typ
}
func (t *Named) cleanup() {
assert(t.orig.orig == t.orig)
assert(t.inst == nil || t.inst.orig.inst == nil)
// Ensure that every defined type created in the course of type-checking has
// either non-*Named underlying type, or is unexpanded.
//
@ -243,15 +263,20 @@ func (t *Named) cleanup() {
// Obj returns the type name for the declaration defining the named type t. For
// instantiated types, this is same as the type name of the origin type.
func (t *Named) Obj() *TypeName {
return t.orig.obj // for non-instances this is the same as t.obj
if t.inst == nil {
return t.obj
}
return t.inst.orig.obj
}
// Origin returns the generic type from which the named type t is
// instantiated. If t is not an instantiated type, the result is t.
func (t *Named) Origin() *Named { return t.orig }
// TODO(gri) Come up with a better representation and API to distinguish
// between parameterized instantiated and non-instantiated types.
func (t *Named) Origin() *Named {
if t.inst == nil {
return t
}
return t.inst.orig
}
// TypeParams returns the type parameters of the named type t, or nil.
// The result is non-nil for an (originally) generic type even if it is instantiated.
@ -260,19 +285,26 @@ func (t *Named) TypeParams() *TypeParamList { return t.resolve(nil).tparams }
// SetTypeParams sets the type parameters of the named type t.
// t must not have type arguments.
func (t *Named) SetTypeParams(tparams []*TypeParam) {
assert(t.targs.Len() == 0)
assert(t.inst == nil)
t.resolve(nil).tparams = bindTParams(tparams)
}
// TypeArgs returns the type arguments used to instantiate the named type t.
func (t *Named) TypeArgs() *TypeList { return t.targs }
func (t *Named) TypeArgs() *TypeList {
if t.inst == nil {
return nil
}
return t.inst.targs
}
// NumMethods returns the number of explicit methods defined for t.
//
// For an ordinary or instantiated type t, the receiver base type of these
// methods will be the named type t. For an uninstantiated generic type t, each
// method receiver will be instantiated with its receiver type parameters.
func (t *Named) NumMethods() int { return len(t.orig.resolve(nil).methods) }
func (t *Named) NumMethods() int {
return len(t.Origin().resolve(nil).methods)
}
// Method returns the i'th method of named type t for 0 <= i < t.NumMethods().
func (t *Named) Method(i int) *Func {
@ -282,23 +314,24 @@ func (t *Named) Method(i int) *Func {
return t.methods[i]
}
assert(t.TypeArgs().Len() > 0) // only instances should have incomplete methods
assert(t.inst != nil) // only instances should have incomplete methods
orig := t.inst.orig
t.mu.Lock()
defer t.mu.Unlock()
if len(t.methods) != len(t.orig.methods) {
if len(t.methods) != len(orig.methods) {
assert(len(t.methods) == 0)
t.methods = make([]*Func, len(t.orig.methods))
t.methods = make([]*Func, len(orig.methods))
}
if t.methods[i] == nil {
t.methods[i] = t.expandMethod(i)
t.expandedMethods++
t.inst.expandedMethods++
// Check if we've created all methods at this point. If we have, mark the
// type as fully expanded.
if t.expandedMethods == len(t.orig.methods) {
if t.inst.expandedMethods == len(orig.methods) {
t.setState(complete)
}
}
@ -309,11 +342,9 @@ func (t *Named) Method(i int) *Func {
// expandMethod substitutes type arguments in the i'th method for an
// instantiated receiver.
func (t *Named) expandMethod(i int) *Func {
assert(t.TypeArgs().Len() > 0) // t must be an instance
// t.orig.methods is not lazy. origm is the method instantiated with its
// receiver type parameters (the "origin" method).
origm := t.orig.Method(i)
origm := t.inst.orig.Method(i)
assert(origm != nil)
check := t.check
@ -340,9 +371,9 @@ func (t *Named) expandMethod(i int) *Func {
// We can only substitute if we have a correspondence between type arguments
// and type parameters. This check is necessary in the presence of invalid
// code.
if origSig.RecvTypeParams().Len() == t.targs.Len() {
if origSig.RecvTypeParams().Len() == t.inst.targs.Len() {
ctxt := check.bestContext(nil)
smap := makeSubstMap(origSig.RecvTypeParams().list(), t.targs.list())
smap := makeSubstMap(origSig.RecvTypeParams().list(), t.inst.targs.list())
sig = check.subst(origm.pos, origSig, smap, ctxt).(*Signature)
}
@ -367,7 +398,7 @@ func (t *Named) expandMethod(i int) *Func {
// SetUnderlying sets the underlying type and marks t as complete.
// t must not have type arguments.
func (t *Named) SetUnderlying(underlying Type) {
assert(t.targs.Len() == 0)
assert(t.inst == nil)
if underlying == nil {
panic("underlying type must not be nil")
}
@ -383,7 +414,7 @@ func (t *Named) SetUnderlying(underlying Type) {
// AddMethod adds method m unless it is already in the method list.
// t must not have type arguments.
func (t *Named) AddMethod(m *Func) {
assert(t.targs.Len() == 0)
assert(t.inst == nil)
t.resolve(nil)
if i, _ := lookupMethod(t.methods, m.pkg, m.name, false); i < 0 {
t.methods = append(t.methods, m)
@ -495,7 +526,7 @@ func (n *Named) lookupMethod(pkg *Package, name string, foldCase bool) (int, *Fu
// If n is an instance, we may not have yet instantiated all of its methods.
// Look up the method index in orig, and only instantiate method at the
// matching index (if any).
i, _ := lookupMethod(n.orig.methods, pkg, name, foldCase)
i, _ := lookupMethod(n.Origin().methods, pkg, name, foldCase)
if i < 0 {
return -1, nil
}
@ -533,36 +564,39 @@ func (n *Named) expandUnderlying(ctxt *Context) Type {
}()
}
assert(n.orig.underlying != nil)
assert(n.inst.orig.underlying != nil)
if _, unexpanded := n.orig.underlying.(*Named); unexpanded {
orig := n.inst.orig
targs := n.inst.targs
if _, unexpanded := orig.underlying.(*Named); unexpanded {
// We should only get a Named underlying type here during type checking
// (for example, in recursive type declarations).
assert(check != nil)
}
if n.orig.tparams.Len() != n.targs.Len() {
if orig.tparams.Len() != targs.Len() {
// Mismatching arg and tparam length may be checked elsewhere.
return Typ[Invalid]
}
// We must always have a context, to avoid infinite recursion.
ctxt = check.bestContext(ctxt)
h := ctxt.instanceHash(n.orig, n.targs.list())
h := ctxt.instanceHash(orig, targs.list())
// ensure that an instance is recorded for h to avoid infinite recursion.
ctxt.update(h, n.orig, n.TypeArgs().list(), n)
ctxt.update(h, orig, targs.list(), n)
smap := makeSubstMap(n.orig.tparams.list(), n.targs.list())
underlying := n.check.subst(n.obj.pos, n.orig.underlying, smap, ctxt)
smap := makeSubstMap(orig.tparams.list(), targs.list())
underlying := n.check.subst(n.obj.pos, orig.underlying, smap, ctxt)
// If the underlying type of n is an interface, we need to set the receiver
// of its methods accurately -- we set the receiver of interface methods on
// the RHS of a type declaration to the defined type.
if iface, _ := underlying.(*Interface); iface != nil {
if methods, copied := replaceRecvType(iface.methods, n.orig, n); copied {
if methods, copied := replaceRecvType(iface.methods, orig, n); copied {
// If the underlying type doesn't actually use type parameters, it's
// possible that it wasn't substituted. In this case we need to create
// a new *Interface before modifying receivers.
if iface == n.orig.underlying {
if iface == orig.underlying {
old := iface
iface = check.newInterface()
iface.embeddeds = old.embeddeds
@ -573,6 +607,7 @@ func (n *Named) expandUnderlying(ctxt *Context) Type {
iface.methods = methods
}
}
return underlying
}

4
src/go/types/predicates.go
View file

@ -104,7 +104,7 @@ func isTypeParam(t Type) bool {
func isGeneric(t Type) bool {
// A parameterized type is only generic if it doesn't have an instantiation already.
named, _ := t.(*Named)
return named != nil && named.obj != nil && named.targs == nil && named.TypeParams() != nil
return named != nil && named.obj != nil && named.inst == nil && named.TypeParams().Len() > 0
}
// Comparable reports whether values of type T are comparable.
@ -403,7 +403,7 @@ func identical(x, y Type, cmpTags bool, p *ifacePair) bool {
if len(xargs) > 0 {
// Instances are identical if their original type and type arguments
// are identical.
if !Identical(x.orig, y.orig) {
if !Identical(x.Origin(), y.Origin()) {
return false
}
for i, xa := range xargs {

2
src/go/types/sizeof_test.go
View file

@ -30,7 +30,7 @@ func TestSizeof(t *testing.T) {
{Interface{}, 40, 80},
{Map{}, 16, 32},
{Chan{}, 12, 24},
{Named{}, 68, 128},
{Named{}, 60, 112},
{TypeParam{}, 28, 48},
{term{}, 12, 24},

25
src/go/types/subst.go
View file

@ -176,7 +176,7 @@ func (subst *subster) typ(typ Type) Type {
// In this case the interface will not be substituted here, because its
// method signatures do not depend on the type parameter P, but we still
// need to create new interface methods to hold the instantiated
// receiver. This is handled by expandNamed.
// receiver. This is handled by Named.expandUnderlying.
iface.methods, _ = replaceRecvType(methods, t, iface)
return iface
}
@ -207,19 +207,20 @@ func (subst *subster) typ(typ Type) Type {
}
}
// subst is called by expandNamed, so in this function we need to be
// subst is called during expansion, so in this function we need to be
// careful not to call any methods that would cause t to be expanded: doing
// so would result in deadlock.
//
// So we call t.orig.TypeParams() rather than t.TypeParams() here and
// below.
if t.orig.TypeParams().Len() == 0 {
// So we call t.Origin().TypeParams() rather than t.TypeParams().
orig := t.Origin()
n := orig.TypeParams().Len()
if n == 0 {
dump(">>> %s is not parameterized", t)
return t // type is not parameterized
}
var newTArgs []Type
if t.targs.Len() != t.orig.TypeParams().Len() {
if t.TypeArgs().Len() != n {
return Typ[Invalid] // error reported elsewhere
}
@ -228,14 +229,14 @@ func (subst *subster) typ(typ Type) Type {
// For each (existing) type argument targ, determine if it needs
// to be substituted; i.e., if it is or contains a type parameter
// that has a type argument for it.
for i, targ := range t.targs.list() {
for i, targ := range t.TypeArgs().list() {
dump(">>> %d targ = %s", i, targ)
new_targ := subst.typ(targ)
if new_targ != targ {
dump(">>> substituted %d targ %s => %s", i, targ, new_targ)
if newTArgs == nil {
newTArgs = make([]Type, t.orig.TypeParams().Len())
copy(newTArgs, t.targs.list())
newTArgs = make([]Type, n)
copy(newTArgs, t.TypeArgs().list())
}
newTArgs[i] = new_targ
}
@ -247,9 +248,9 @@ func (subst *subster) typ(typ Type) Type {
}
// before creating a new named type, check if we have this one already
h := subst.ctxt.instanceHash(t.orig, newTArgs)
h := subst.ctxt.instanceHash(orig, newTArgs)
dump(">>> new type hash: %s", h)
if named := subst.ctxt.lookup(h, t.orig, newTArgs); named != nil {
if named := subst.ctxt.lookup(h, orig, newTArgs); named != nil {
dump(">>> found %s", named)
return named
}
@ -258,7 +259,7 @@ func (subst *subster) typ(typ Type) Type {
// recursion. The position used here is irrelevant because validation only
// occurs on t (we don't call validType on named), but we use subst.pos to
// help with debugging.
return subst.check.instance(subst.pos, t.orig, newTArgs, subst.ctxt)
return subst.check.instance(subst.pos, orig, newTArgs, subst.ctxt)
// Note that if we were to expose substitution more generally (not just in
// the context of a declaration), we'd have to substitute in

4
src/go/types/typestring.go
View file

@ -285,9 +285,9 @@ func (w *typeWriter) typ(typ Type) {
w.string(strconv.Itoa(w.ctxt.getID(t)))
}
w.typeName(t.obj) // when hashing written for readability of the hash only
if t.targs != nil {
if t.inst != nil {
// instantiated type
w.typeList(t.targs.list())
w.typeList(t.inst.targs.list())
} else if w.ctxt == nil && t.TypeParams().Len() != 0 { // For type hashing, don't need to format the TypeParams
// parameterized type
w.tParamList(t.TypeParams().list())

6
src/go/types/typexpr.go
View file

@ -428,8 +428,8 @@ func (check *Checker) instantiatedType(ix *typeparams.IndexExpr, def *Named) (re
// errors.
check.recordInstance(ix.Orig, inst.TypeArgs().list(), inst)
if check.validateTArgLen(ix.Pos(), inst.TypeParams().Len(), inst.targs.Len()) {
if i, err := check.verify(ix.Pos(), inst.TypeParams().list(), inst.targs.list()); err != nil {
if check.validateTArgLen(ix.Pos(), inst.TypeParams().Len(), inst.TypeArgs().Len()) {
if i, err := check.verify(ix.Pos(), inst.TypeParams().list(), inst.TypeArgs().list()); err != nil {
// best position for error reporting
pos := ix.Pos()
if i < len(ix.Indices) {
@ -437,7 +437,7 @@ func (check *Checker) instantiatedType(ix *typeparams.IndexExpr, def *Named) (re
}
check.softErrorf(atPos(pos), _InvalidTypeArg, err.Error())
} else {
check.mono.recordInstance(check.pkg, ix.Pos(), inst.TypeParams().list(), inst.targs.list(), ix.Indices)
check.mono.recordInstance(check.pkg, ix.Pos(), inst.TypeParams().list(), inst.TypeArgs().list(), ix.Indices)
}
}

4
src/go/types/unify.go
View file

@ -546,8 +546,8 @@ func (u *unifier) nify(x, y Type, p *ifacePair) (result bool) {
case *Named:
// TODO(gri) This code differs now from the parallel code in Checker.identical. Investigate.
if y, ok := y.(*Named); ok {
xargs := x.targs.list()
yargs := y.targs.list()
xargs := x.TypeArgs().list()
yargs := y.TypeArgs().list()
if len(xargs) != len(yargs) {
return false

2
src/go/types/validtype.go
View file

@ -71,7 +71,7 @@ func (check *Checker) validType0(typ Type, env *tparamEnv, path []Object) typeIn
switch check.infoMap[t] {
case unknown:
check.infoMap[t] = marked
check.infoMap[t] = check.validType0(t.orig.fromRHS, env.push(t), append(path, t.obj))
check.infoMap[t] = check.validType0(t.Origin().fromRHS, env.push(t), append(path, t.obj))
case marked:
// We have seen type t before and thus must have a cycle.
check.infoMap[t] = invalid