cmd/compile: deprecate has init and derived func instance

Removes 'has init' and 'derived func instance' fields from unified IR
starting with V2.

This should be a no-op at the moment as the writer is hardwired to create V1.

Updates #68778

Change-Id: I84a606cbc27cd6d8bd6eee2aff44c89f4aa7413c
Reviewed-on: https://go-review.googlesource.com/c/go/+/606035
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Reviewed-by: Robert Griesemer <gri@google.com>
Reviewed-by: David Chase <drchase@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>

src/cmd/compile/internal/importer/ureader.go

@@ -39,13 +39,18 @@ func ReadPackage(ctxt *types2.Context, imports map[string]*types2.Package, input
 
 	r := pr.newReader(pkgbits.RelocMeta, pkgbits.PublicRootIdx, pkgbits.SyncPublic)
 	pkg := r.pkg()
-	r.Bool() // TODO(mdempsky): Remove; was "has init"
+
+	if r.Version().Has(pkgbits.HasInit) {
+		r.Bool()
+	}
 
 	for i, n := 0, r.Len(); i < n; i++ {
 		// As if r.obj(), but avoiding the Scope.Lookup call,
 		// to avoid eager loading of imports.
 		r.Sync(pkgbits.SyncObject)
-		assert(!r.Bool())
+		if r.Version().Has(pkgbits.DerivedFuncInstance) {
+			assert(!r.Bool())
+		}
 		r.p.objIdx(r.Reloc(pkgbits.RelocObj))
 		assert(r.Len() == 0)
 	}
@@ -366,7 +371,9 @@ func (r *reader) param() *types2.Var {
 func (r *reader) obj() (types2.Object, []types2.Type) {
 	r.Sync(pkgbits.SyncObject)
 
-	assert(!r.Bool())
+	if r.Version().Has(pkgbits.DerivedFuncInstance) {
+		assert(!r.Bool())
+	}
 
 	pkg, name := r.p.objIdx(r.Reloc(pkgbits.RelocObj))
 	obj := pkg.Scope().Lookup(name)

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

@@ -640,7 +640,9 @@ func (r *reader) obj() ir.Node {
 // and returns the encoded reference to it, without instantiating it.
 func (r *reader) objInfo() objInfo {
 	r.Sync(pkgbits.SyncObject)
-	assert(!r.Bool()) // TODO(mdempsky): Remove; was derived func inst.
+	if r.Version().Has(pkgbits.DerivedFuncInstance) {
+		assert(!r.Bool())
+	}
 	idx := r.Reloc(pkgbits.RelocObj)
 
 	explicits := make([]typeInfo, r.Len())

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

@@ -329,7 +329,10 @@ func writePkgStub(m posMap, noders []*noder) string {
 	{
 		w := publicRootWriter
 		w.pkg(pkg)
-		w.Bool(false) // TODO(mdempsky): Remove; was "has init"
+
+		if w.Version().Has(pkgbits.HasInit) {
+			w.Bool(false)
+		}
 
 		scope := pkg.Scope()
 		names := scope.Names()
@@ -410,11 +413,15 @@ func readPackage(pr *pkgReader, importpkg *types.Pkg, localStub bool) {
 			base.ErrorExit()
 		}
 
-		r.Bool() // TODO(mdempsky): Remove; was "has init"
+		if r.Version().Has(pkgbits.HasInit) {
+			r.Bool()
+		}
 
 		for i, n := 0, r.Len(); i < n; i++ {
 			r.Sync(pkgbits.SyncObject)
-			assert(!r.Bool())
+			if r.Version().Has(pkgbits.DerivedFuncInstance) {
+				assert(!r.Bool())
+			}
 			idx := r.Reloc(pkgbits.RelocObj)
 			assert(r.Len() == 0)
 
@@ -477,11 +484,15 @@ func writeUnifiedExport(out io.Writer) {
 		r.Sync(pkgbits.SyncPkg)
 		selfPkgIdx = l.relocIdx(pr, pkgbits.RelocPkg, r.Reloc(pkgbits.RelocPkg))
 
-		r.Bool() // TODO(mdempsky): Remove; was "has init"
+		if r.Version().Has(pkgbits.HasInit) {
+			r.Bool()
+		}
 
 		for i, n := 0, r.Len(); i < n; i++ {
 			r.Sync(pkgbits.SyncObject)
-			assert(!r.Bool())
+			if r.Version().Has(pkgbits.DerivedFuncInstance) {
+				assert(!r.Bool())
+			}
 			idx := r.Reloc(pkgbits.RelocObj)
 			assert(r.Len() == 0)
 
@@ -508,12 +519,17 @@ func writeUnifiedExport(out io.Writer) {
 
 		w.Sync(pkgbits.SyncPkg)
 		w.Reloc(pkgbits.RelocPkg, selfPkgIdx)
-		w.Bool(false) // TODO(mdempsky): Remove; was "has init"
+
+		if w.Version().Has(pkgbits.HasInit) {
+			w.Bool(false)
+		}
 
 		w.Len(len(idxs))
 		for _, idx := range idxs {
 			w.Sync(pkgbits.SyncObject)
-			w.Bool(false)
+			if w.Version().Has(pkgbits.DerivedFuncInstance) {
+				w.Bool(false)
+			}
 			w.Reloc(pkgbits.RelocObj, idx)
 			w.Len(0)
 		}

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

@@ -730,7 +730,9 @@ func (w *writer) obj(obj types2.Object, explicits *types2.TypeList) {
 // bitstream.
 func (w *writer) objInfo(info objInfo) {
 	w.Sync(pkgbits.SyncObject)
-	w.Bool(false) // TODO(mdempsky): Remove; was derived func inst.
+	if w.Version().Has(pkgbits.DerivedFuncInstance) {
+		w.Bool(false)
+	}
 	w.Reloc(pkgbits.RelocObj, info.idx)
 
 	w.Len(len(info.explicits))

src/go/internal/gcimporter/ureader.go

@@ -65,13 +65,17 @@ func readUnifiedPackage(fset *token.FileSet, ctxt *types.Context, imports map[st
 
 	r := pr.newReader(pkgbits.RelocMeta, pkgbits.PublicRootIdx, pkgbits.SyncPublic)
 	pkg := r.pkg()
-	r.Bool() // TODO(mdempsky): Remove; was "has init"
+	if r.Version().Has(pkgbits.HasInit) {
+		r.Bool()
+	}
 
 	for i, n := 0, r.Len(); i < n; i++ {
 		// As if r.obj(), but avoiding the Scope.Lookup call,
 		// to avoid eager loading of imports.
 		r.Sync(pkgbits.SyncObject)
-		assert(!r.Bool())
+		if r.Version().Has(pkgbits.DerivedFuncInstance) {
+			assert(!r.Bool())
+		}
 		r.p.objIdx(r.Reloc(pkgbits.RelocObj))
 		assert(r.Len() == 0)
 	}
@@ -428,7 +432,9 @@ func (r *reader) param() *types.Var {
 func (r *reader) obj() (types.Object, []types.Type) {
 	r.Sync(pkgbits.SyncObject)
 
-	assert(!r.Bool())
+	if r.Version().Has(pkgbits.DerivedFuncInstance) {
+		assert(!r.Bool())
+	}
 
 	pkg, name := r.p.objIdx(r.Reloc(pkgbits.RelocObj))
 	obj := pkgScope(pkg).Lookup(name)