qbit/go
1
0
Fork 0
mirror of https://github.com/golang/go synced 2024-11-17 10:14:46 -07:00
Code Releases Activity

cmd/compile/internal/types2: remove need for instance (struct)

Browse Source 
instance was only used to hold the instantiation position for
lazy instantiation (and encode the fact that we have a lazy
instantiation). Just use a (pointer to a) syntax.Pos instead.

We could use a syntax.Pos (no pointer) and rely on the fact
that we have a known position (or fake position, if need be)
to indicate lazy instantiation. But using a pointer leads to
a smaller Named struct.

Change-Id: I441a839a125f453ad6c501de1ce499b72a2f67a4
Reviewed-on: https://go-review.googlesource.com/c/go/+/345177
Trust: Robert Griesemer <gri@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
This commit is contained in:
Robert Griesemer 2021-08-25 21:48:21 -07:00
parent d6bdae33e9
commit 166b691b65
3 changed files with 7 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
src/cmd/compile/internal/types2/instantiate.go
View File

@ -136,7 +136,7 @@ func (check *Checker) instance(pos syntax.Pos, typ Type, targs []Type) Type {
tname := NewTypeName(pos, t.obj.pkg, t.obj.name, nil)
named := check.newNamed(tname, t, nil, nil, nil) // methods and tparams are set when named is loaded
named.targs = NewTypeList(targs)
named.instance = &instance{pos}
named.instPos = &pos
if check != nil {
check.typMap[h] = named
}

18
src/cmd/compile/internal/types2/named.go
View File

@ -17,7 +17,7 @@ type Named struct {
orig *Named // original, uninstantiated type
fromRHS Type // type (on RHS of declaration) this *Named type is derived from (for cycle reporting)
underlying Type // possibly a *Named during setup; never a *Named once set up completely
instance *instance // position information for lazy instantiation, or nil
instPos *syntax.Pos // position information for lazy instantiation, or nil
tparams *TParamList // type parameters, or nil
targs *TypeList // type arguments (after instantiation), or nil
methods []*Func // methods declared for this type (not the method set of this type); signatures are type-checked lazily
@ -240,24 +240,16 @@ func (n *Named) setUnderlying(typ Type) {
}
}
// instance holds position information for use in lazy instantiation.
//
// TODO(rfindley): instance is probably unnecessary now. See if it can be
// eliminated.
type instance struct {
pos syntax.Pos // position of type instantiation; for error reporting only
}
// expand ensures that the underlying type of n is instantiated.
// The underlying type will be Typ[Invalid] if there was an error.
func (n *Named) expand(typMap map[string]*Named) *Named {
if n.instance != nil {
if n.instPos != nil {
// n must be loaded before instantiation, in order to have accurate
// tparams. This is done implicitly by the call to n.TParams, but making it
// explicit is harmless: load is idempotent.
n.load()
var u Type
if n.check.validateTArgLen(n.instance.pos, n.tparams.Len(), n.targs.Len()) {
if n.check.validateTArgLen(*n.instPos, n.tparams.Len(), n.targs.Len()) {
if typMap == nil {
if n.check != nil {
typMap = n.check.typMap
@ -270,13 +262,13 @@ func (n *Named) expand(typMap map[string]*Named) *Named {
typMap = map[string]*Named{h: n}
}
}
u = n.check.subst(n.instance.pos, n.orig.underlying, makeSubstMap(n.TParams().list(), n.targs.list()), typMap)
u = n.check.subst(*n.instPos, n.orig.underlying, makeSubstMap(n.TParams().list(), n.targs.list()), typMap)
} else {
u = Typ[Invalid]
}
n.underlying = u
n.fromRHS = u
n.instance = nil
n.instPos = nil
}
return n
}

2
src/cmd/compile/internal/types2/typestring.go
View File

@ -195,7 +195,7 @@ func writeType(buf *bytes.Buffer, typ Type, qf Qualifier, visited []Type) {
}
case *Named:
if t.instance != nil {
if t.instPos != nil {
buf.WriteByte(instanceMarker)
}
writeTypeName(buf, t.obj, qf)