cmd/compile/internal/types: remove unneeded functionality

This CL removes a handful of features that were only needed for the
pre-unified frontends.

In particular, Type.Pkg was a hack for iexport so that
go/types.Var.Pkg could be precisely populated for struct fields and
signature parameters by gcimporter, but it's no longer necessary with
the unified export data format because we now write export data
directly from types2-supplied type descriptors.

Several other features (e.g., OrigType, implicit interfaces, type
parameters on signatures) are no longer relevant to the unified
frontend, because it only uses types1 to represent instantiated
generic types.

Updates #57410.

Change-Id: I84fd1da5e0b65d2ab91d244a7bb593821ee916e7
Reviewed-on: https://go-review.googlesource.com/c/go/+/458622
Reviewed-by: Keith Randall <khr@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Keith Randall <khr@golang.org>

1 files changed, 20 insertions, 25 deletions

diff --git a/src/cmd/compile/internal/noder/reader.go b/src/cmd/compile/internal/noder/reader.go
index ac6d2fa931..8a8ed8608c 100644
--- a/src/cmd/compile/internal/noder/reader.go
+++ b/src/cmd/compile/internal/noder/reader.go
@@ -506,7 +506,7 @@ func (r *reader) doTyp() *types.Type {
 	case pkgbits.TypePointer:
 		return types.NewPtr(r.typ())
 	case pkgbits.TypeSignature:
-		return r.signature(types.LocalPkg, nil)
+		return r.signature(nil)
 	case pkgbits.TypeSlice:
 		return types.NewSlice(r.typ())
 	case pkgbits.TypeStruct:
@@ -549,8 +549,6 @@ func (r *reader) unionType() *types.Type {
 }
 
 func (r *reader) interfaceType() *types.Type {
-	tpkg := types.LocalPkg // TODO(mdempsky): Remove after iexport is gone.
-
 	nmethods, nembeddeds := r.Len(), r.Len()
 	implicit := nmethods == 0 && nembeddeds == 1 && r.Bool()
 	assert(!implicit) // implicit interfaces only appear in constraints
@@ -560,9 +558,8 @@ func (r *reader) interfaceType() *types.Type {
 
 	for i := range methods {
 		pos := r.pos()
-		pkg, sym := r.selector()
-		tpkg = pkg
-		mtyp := r.signature(pkg, types.FakeRecv())
+		_, sym := r.selector()
+		mtyp := r.signature(types.FakeRecv())
 		methods[i] = types.NewField(pos, sym, mtyp)
 	}
 	for i := range embeddeds {
@@ -572,16 +569,14 @@ func (r *reader) interfaceType() *types.Type {
 	if len(fields) == 0 {
 		return types.Types[types.TINTER] // empty interface
 	}
-	return types.NewInterface(tpkg, fields, false)
+	return types.NewInterface(fields)
 }
 
 func (r *reader) structType() *types.Type {
-	tpkg := types.LocalPkg // TODO(mdempsky): Remove after iexport is gone.
 	fields := make([]*types.Field, r.Len())
 	for i := range fields {
 		pos := r.pos()
-		pkg, sym := r.selector()
-		tpkg = pkg
+		_, sym := r.selector()
 		ftyp := r.typ()
 		tag := r.String()
 		embedded := r.Bool()
@@ -593,26 +588,26 @@ func (r *reader) structType() *types.Type {
 		}
 		fields[i] = f
 	}
-	return types.NewStruct(tpkg, fields)
+	return types.NewStruct(fields)
 }
 
-func (r *reader) signature(tpkg *types.Pkg, recv *types.Field) *types.Type {
+func (r *reader) signature(recv *types.Field) *types.Type {
 	r.Sync(pkgbits.SyncSignature)
 
-	params := r.params(&tpkg)
-	results := r.params(&tpkg)
+	params := r.params()
+	results := r.params()
 	if r.Bool() { // variadic
 		params[len(params)-1].SetIsDDD(true)
 	}
 
-	return types.NewSignature(tpkg, recv, nil, params, results)
+	return types.NewSignature(recv, params, results)
 }
 
-func (r *reader) params(tpkg **types.Pkg) []*types.Field {
+func (r *reader) params() []*types.Field {
 	r.Sync(pkgbits.SyncParams)
 	fields := make([]*types.Field, r.Len())
 	for i := range fields {
-		*tpkg, fields[i] = r.param()
+		_, fields[i] = r.param()
 	}
 	return fields
 }
@@ -742,7 +737,7 @@ func (pr *pkgReader) objIdx(idx pkgbits.Index, implicits, explicits []*types.Typ
 			sym = Renameinit()
 		}
 		name := do(ir.ONAME, true)
-		setType(name, r.signature(sym.Pkg, nil))
+		setType(name, r.signature(nil))
 
 		name.Func = ir.NewFunc(r.pos())
 		name.Func.Nname = name
@@ -981,10 +976,10 @@ func (r *reader) typeParamNames() {
 func (r *reader) method(rext *reader) *types.Field {
 	r.Sync(pkgbits.SyncMethod)
 	pos := r.pos()
-	pkg, sym := r.selector()
+	_, sym := r.selector()
 	r.typeParamNames()
 	_, recv := r.param()
-	typ := r.signature(pkg, recv)
+	typ := r.signature(recv)
 
 	name := ir.NewNameAt(pos, ir.MethodSym(recv.Type, sym))
 	setType(name, typ)
@@ -2581,7 +2576,7 @@ func (r *reader) curry(pos src.XPos, ifaceHack bool, fun ir.Node, arg0, arg1 ir.
 
 	params, results := syntheticSig(fun.Type())
 	params = params[len(captured)-1:] // skip curried parameters
-	typ := types.NewSignature(types.NoPkg, nil, nil, params, results)
+	typ := types.NewSignature(nil, params, results)
 
 	addBody := func(pos src.XPos, r *reader, captured []ir.Node) {
 		recvs, params := r.syntheticArgs(pos)
@@ -2619,7 +2614,7 @@ func (r *reader) methodExprWrap(pos src.XPos, recv *types.Type, implicits []int,
 		params = append(params[:1], params[2:]...)
 	}
 
-	typ := types.NewSignature(types.NoPkg, nil, nil, params, results)
+	typ := types.NewSignature(nil, params, results)
 
 	addBody := func(pos src.XPos, r *reader, captured []ir.Node) {
 		recvs, args := r.syntheticArgs(pos)
@@ -3073,7 +3068,7 @@ func (r *reader) funcLit() ir.Node {
 	// allocation of the closure is credited (#49171).
 	r.suppressInlPos++
 	pos := r.pos()
-	xtype2 := r.signature(types.LocalPkg, nil)
+	xtype2 := r.signature(nil)
 	r.suppressInlPos--
 
 	fn := ir.NewClosureFunc(pos, r.curfn != nil)
@@ -3926,7 +3921,7 @@ func newWrapperType(recvType *types.Type, method *types.Field) *types.Type {
 	params := clone(sig.Params().FieldSlice())
 	results := clone(sig.Results().FieldSlice())
 
-	return types.NewSignature(types.NoPkg, recv, nil, params, results)
+	return types.NewSignature(recv, params, results)
 }
 
 func addTailCall(pos src.XPos, fn *ir.Func, recv ir.Node, method *types.Field) {
@@ -3994,5 +3989,5 @@ func shapeSig(fn *ir.Func, dict *readerDict) *types.Type {
 		results[i] = types.NewField(result.Pos, result.Sym, result.Type)
 	}
 
-	return types.NewSignature(types.LocalPkg, recv, nil, params, results)
+	return types.NewSignature(recv, params, results)
 }