cmd/compile: remove 'ext' fields from unified IR reader/writer types

This is a vestigial artifact of how I initially split apart the public
and private data for objects. But now objects are split into more
parts, and it's proven easier to just keep them as separate variables.
So it's time to cleanup the initial public/private code to follow the
same approach.

Change-Id: I3976b19fb433cbe21d299d3799ec616f9e59561e
Reviewed-on: https://go-review.googlesource.com/c/go/+/348412
Trust: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>

src/cmd/compile/internal/noder/reader.go

@@ -79,8 +79,6 @@ type reader struct {
 
 	p *pkgReader
 
-	ext *reader
-
 	dict *readerDict
 
 	// TODO(mdempsky): The state below is all specific to reading
@@ -586,10 +584,10 @@ func (pr *pkgReader) objIdx(idx int, implicits, explicits []*types.Type) ir.Node
 	dict := pr.objDictIdx(sym, idx, implicits, explicits)
 
 	r := pr.newReader(relocObj, idx, syncObject1)
-	r.ext = pr.newReader(relocObjExt, idx, syncObject1)
+	rext := pr.newReader(relocObjExt, idx, syncObject1)
 
 	r.dict = dict
-	r.ext.dict = dict
+	rext.dict = dict
 
 	sym = r.mangle(sym)
 	if !sym.IsBlank() && sym.Def != nil {
@@ -642,7 +640,7 @@ func (pr *pkgReader) objIdx(idx int, implicits, explicits []*types.Type) ir.Node
 		name.Func = ir.NewFunc(r.pos())
 		name.Func.Nname = name
 
-		r.ext.funcExt(name)
+		rext.funcExt(name)
 		return name
 
 	case objType:
@@ -651,7 +649,7 @@ func (pr *pkgReader) objIdx(idx int, implicits, explicits []*types.Type) ir.Node
 		setType(name, typ)
 
 		// Important: We need to do this before SetUnderlying.
-		r.ext.typeExt(name)
+		rext.typeExt(name)
 
 		// We need to defer CheckSize until we've called SetUnderlying to
 		// handle recursive types.
@@ -661,7 +659,7 @@ func (pr *pkgReader) objIdx(idx int, implicits, explicits []*types.Type) ir.Node
 
 		methods := make([]*types.Field, r.len())
 		for i := range methods {
-			methods[i] = r.method()
+			methods[i] = r.method(rext)
 		}
 		if len(methods) != 0 {
 			typ.Methods().Set(methods)
@@ -674,7 +672,7 @@ func (pr *pkgReader) objIdx(idx int, implicits, explicits []*types.Type) ir.Node
 	case objVar:
 		name := do(ir.ONAME, false)
 		setType(name, r.typ())
-		r.ext.varExt(name)
+		rext.varExt(name)
 		return name
 	}
 }
@@ -756,7 +754,7 @@ func (r *reader) typeParamNames() {
 	}
 }
 
-func (r *reader) method() *types.Field {
+func (r *reader) method(rext *reader) *types.Field {
 	r.sync(syncMethod)
 	pos := r.pos()
 	pkg, sym := r.selector()
@@ -772,7 +770,7 @@ func (r *reader) method() *types.Field {
 	name.Func = ir.NewFunc(r.pos())
 	name.Func.Nname = name
 
-	r.ext.funcExt(name)
+	rext.funcExt(name)
 
 	meth := types.NewField(name.Func.Pos(), sym, typ)
 	meth.Nname = name

src/cmd/compile/internal/noder/unified.go

@@ -106,7 +106,6 @@ func unified(noders []*noder) {
 	readPackage(localPkgReader, types.LocalPkg)
 
 	r := localPkgReader.newReader(relocMeta, privateRootIdx, syncPrivate)
-	r.ext = r
 	r.pkgInit(types.LocalPkg, target)
 
 	// Type-check any top-level assignments. We ignore non-assignments
@@ -190,7 +189,6 @@ func writePkgStub(noders []*noder) string {
 
 	{
 		w := privateRootWriter
-		w.ext = w
 		w.pkgInit(noders)
 		w.flush()
 	}

src/cmd/compile/internal/noder/writer.go

@@ -75,14 +75,6 @@ type writer struct {
 
 	encoder
 
-	// For writing out object descriptions, ext points to the extension
-	// writer for where we can write the compiler's private extension
-	// details for the object.
-	//
-	// TODO(mdempsky): This is a little hacky, but works easiest with
-	// the way things are currently.
-	ext *writer
-
 	// TODO(mdempsky): We should be able to prune localsIdx whenever a
 	// scope closes, and then maybe we can just use the same map for
 	// storing the TypeParams too (as their TypeName instead).
@@ -504,21 +496,21 @@ func (pw *pkgWriter) objIdx(obj types2.Object) int {
 	}
 
 	w := pw.newWriter(relocObj, syncObject1)
-	w.ext = pw.newWriter(relocObjExt, syncObject1)
+	wext := pw.newWriter(relocObjExt, syncObject1)
 	wname := pw.newWriter(relocName, syncObject1)
 	wdict := pw.newWriter(relocObjDict, syncObject1)
 
 	pw.globalsIdx[obj] = w.idx // break cycles
-	assert(w.ext.idx == w.idx)
+	assert(wext.idx == w.idx)
 	assert(wname.idx == w.idx)
 	assert(wdict.idx == w.idx)
 
 	w.dict = dict
-	w.ext.dict = dict
+	wext.dict = dict
 
-	code := w.doObj(obj)
+	code := w.doObj(wext, obj)
 	w.flush()
-	w.ext.flush()
+	wext.flush()
 
 	wname.qualifiedIdent(obj)
 	wname.code(code)
@@ -530,7 +522,7 @@ func (pw *pkgWriter) objIdx(obj types2.Object) int {
 	return w.idx
 }
 
-func (w *writer) doObj(obj types2.Object) codeObj {
+func (w *writer) doObj(wext *writer, obj types2.Object) codeObj {
 	if obj.Pkg() != w.p.curpkg {
 		return objStub
 	}
@@ -555,7 +547,7 @@ func (w *writer) doObj(obj types2.Object) codeObj {
 		w.typeParamNames(sig.TypeParams())
 		w.signature(sig)
 		w.pos(decl)
-		w.ext.funcExt(obj)
+		wext.funcExt(obj)
 		return objFunc
 
 	case *types2.TypeName:
@@ -573,12 +565,12 @@ func (w *writer) doObj(obj types2.Object) codeObj {
 
 		w.pos(obj)
 		w.typeParamNames(named.TypeParams())
-		w.ext.typeExt(obj)
+		wext.typeExt(obj)
 		w.typExpr(decl.Type)
 
 		w.len(named.NumMethods())
 		for i := 0; i < named.NumMethods(); i++ {
-			w.method(named.Method(i))
+			w.method(wext, named.Method(i))
 		}
 
 		return objType
@@ -586,7 +578,7 @@ func (w *writer) doObj(obj types2.Object) codeObj {
 	case *types2.Var:
 		w.pos(obj)
 		w.typ(obj.Type())
-		w.ext.varExt(obj)
+		wext.varExt(obj)
 		return objVar
 	}
 }
@@ -648,7 +640,7 @@ func (w *writer) typeParamNames(tparams *types2.TypeParamList) {
 	}
 }
 
-func (w *writer) method(meth *types2.Func) {
+func (w *writer) method(wext *writer, meth *types2.Func) {
 	decl, ok := w.p.funDecls[meth]
 	assert(ok)
 	sig := meth.Type().(*types2.Signature)
@@ -661,7 +653,7 @@ func (w *writer) method(meth *types2.Func) {
 	w.signature(sig)
 
 	w.pos(decl) // XXX: Hack to workaround linker limitations.
-	w.ext.funcExt(meth)
+	wext.funcExt(meth)
 }
 
 // qualifiedIdent writes out the name of an object declared at package