cmd/compile/internal/noder: remove unused noding code

This CL simplifies and removes some old noding code, which isn't
necessary any more.

Most notably, we no longer need separate posMaps for each noder,
because noders are only used for parsing now. Before we started using
types2, noders were also responsible for constructed (untyped) IR, so
posMaps were necessary to translate syntax.Pos into src.XPos.

Change-Id: Ic761abcd727f5ecefc71b611635a0f5b088c941f
Reviewed-on: https://go-review.googlesource.com/c/go/+/463738
Auto-Submit: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Keith Randall <khr@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>

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

@@ -19,16 +19,14 @@ var versionErrorRx = regexp.MustCompile(`requires go[0-9]+\.[0-9]+ or later`)
 
 // checkFiles configures and runs the types2 checker on the given
 // parsed source files and then returns the result.
-func checkFiles(noders []*noder) (posMap, *types2.Package, *types2.Info) {
+func checkFiles(m posMap, noders []*noder) (*types2.Package, *types2.Info) {
 	if base.SyntaxErrors() != 0 {
 		base.ErrorExit()
 	}
 
 	// setup and syntax error reporting
-	var m posMap
 	files := make([]*syntax.File, len(noders))
 	for i, p := range noders {
-		m.join(&p.posMap)
 		files[i] = p.file
 	}
 
@@ -117,7 +115,7 @@ func checkFiles(noders []*noder) (posMap, *types2.Package, *types2.Info) {
 		base.FatalfAt(src.NoXPos, "conf.Check error: %v", err)
 	}
 
-	return m, pkg, info
+	return pkg, info
 }
 
 // A cycleFinder detects anonymous interface cycles (go.dev/issue/56103).

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

@@ -21,7 +21,6 @@ import (
 	"cmd/compile/internal/typecheck"
 	"cmd/compile/internal/types"
 	"cmd/internal/objabi"
-	"cmd/internal/src"
 )
 
 func LoadPackage(filenames []string) {
@@ -62,9 +61,10 @@ func LoadPackage(filenames []string) {
 	}()
 
 	var lines uint
+	var m posMap
 	for _, p := range noders {
 		for e := range p.err {
-			p.errorAt(e.Pos, "%s", e.Msg)
+			base.ErrorfAt(m.makeXPos(e.Pos), "%s", e.Msg)
 		}
 		if p.file == nil {
 			base.ErrorExit()
@@ -73,11 +73,7 @@ func LoadPackage(filenames []string) {
 	}
 	base.Timer.AddEvent(int64(lines), "lines")
 
-	unified(noders)
-}
-
-func (p *noder) errorAt(pos syntax.Pos, format string, args ...interface{}) {
-	base.ErrorfAt(p.makeXPos(pos), format, args...)
+	unified(m, noders)
 }
 
 // trimFilename returns the "trimmed" filename of b, which is the
@@ -101,14 +97,10 @@ func trimFilename(b *syntax.PosBase) string {
 
 // noder transforms package syntax's AST into a Node tree.
 type noder struct {
-	posMap
-
-	file           *syntax.File
-	linknames      []linkname
-	pragcgobuf     [][]string
-	err            chan syntax.Error
-	importedUnsafe bool
-	importedEmbed  bool
+	file       *syntax.File
+	linknames  []linkname
+	pragcgobuf [][]string
+	err        chan syntax.Error
 }
 
 // linkname records a //go:linkname directive.
@@ -118,28 +110,6 @@ type linkname struct {
 	remote string
 }
 
-func (p *noder) processPragmas() {
-	for _, l := range p.linknames {
-		if !p.importedUnsafe {
-			p.errorAt(l.pos, "//go:linkname only allowed in Go files that import \"unsafe\"")
-			continue
-		}
-		n := ir.AsNode(typecheck.Lookup(l.local).Def)
-		if n == nil || n.Op() != ir.ONAME {
-			if types.AllowsGoVersion(1, 18) {
-				p.errorAt(l.pos, "//go:linkname must refer to declared function or variable")
-			}
-			continue
-		}
-		if n.Sym().Linkname != "" {
-			p.errorAt(l.pos, "duplicate //go:linkname for %s", l.local)
-			continue
-		}
-		n.Sym().Linkname = l.remote
-	}
-	typecheck.Target.CgoPragmas = append(typecheck.Target.CgoPragmas, p.pragcgobuf...)
-}
-
 var unOps = [...]ir.Op{
 	syntax.Recv: ir.ORECV,
 	syntax.Mul:  ir.ODEREF,
@@ -176,23 +146,6 @@ var binOps = [...]ir.Op{
 	syntax.Shr:    ir.ORSH,
 }
 
-func wrapname(pos src.XPos, x ir.Node) ir.Node {
-	// These nodes do not carry line numbers.
-	// Introduce a wrapper node to give them the correct line.
-	switch x.Op() {
-	case ir.OTYPE, ir.OLITERAL:
-		if x.Sym() == nil {
-			break
-		}
-		fallthrough
-	case ir.ONAME, ir.ONONAME:
-		p := ir.NewParenExpr(pos, x)
-		p.SetImplicit(true)
-		return p
-	}
-	return x
-}
-
 // error is called concurrently if files are parsed concurrently.
 func (p *noder) error(err error) {
 	p.err <- err.(syntax.Error)
@@ -442,26 +395,6 @@ func Renameinit() *types.Sym {
 	return s
 }
 
-func varEmbed(makeXPos func(syntax.Pos) src.XPos, name *ir.Name, decl *syntax.VarDecl, pragma *pragmas, haveEmbed bool) {
-	pragmaEmbeds := pragma.Embeds
-	pragma.Embeds = nil
-	if len(pragmaEmbeds) == 0 {
-		return
-	}
-
-	if err := checkEmbed(decl, haveEmbed, typecheck.DeclContext != ir.PEXTERN); err != nil {
-		base.ErrorfAt(makeXPos(pragmaEmbeds[0].Pos), "%s", err)
-		return
-	}
-
-	var embeds []ir.Embed
-	for _, e := range pragmaEmbeds {
-		embeds = append(embeds, ir.Embed{Pos: makeXPos(e.Pos), Patterns: e.Patterns})
-	}
-	typecheck.Target.Embeds = append(typecheck.Target.Embeds, name)
-	name.Embed = &embeds
-}
-
 func checkEmbed(decl *syntax.VarDecl, haveEmbed, withinFunc bool) error {
 	switch {
 	case !haveEmbed:

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

@@ -72,15 +72,3 @@ func (m *posMap) makeSrcPosBase(b0 *syntax.PosBase) *src.PosBase {
 
 	return b1
 }
-
-func (m *posMap) join(other *posMap) {
-	if m.bases == nil {
-		m.bases = make(map[*syntax.PosBase]*src.PosBase)
-	}
-	for k, v := range other.bases {
-		if m.bases[k] != nil {
-			base.Fatalf("duplicate posmap bases")
-		}
-		m.bases[k] = v
-	}
-}

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

@@ -68,11 +68,11 @@ var localPkgReader *pkgReader
 // the unified IR has the full typed AST needed for introspection during step (1).
 // In other words, we have all the necessary information to build the generic IR form
 // (see writer.captureVars for an example).
-func unified(noders []*noder) {
+func unified(m posMap, noders []*noder) {
 	inline.InlineCall = unifiedInlineCall
 	typecheck.HaveInlineBody = unifiedHaveInlineBody
 
-	data := writePkgStub(noders)
+	data := writePkgStub(m, noders)
 
 	// We already passed base.Flag.Lang to types2 to handle validating
 	// the user's source code. Bump it up now to the current version and
@@ -202,8 +202,8 @@ func readBodies(target *ir.Package, duringInlining bool) {
 // writePkgStub type checks the given parsed source files,
 // writes an export data package stub representing them,
 // and returns the result.
-func writePkgStub(noders []*noder) string {
-	m, pkg, info := checkFiles(noders)
+func writePkgStub(m posMap, noders []*noder) string {
+	pkg, info := checkFiles(m, noders)
 
 	pw := newPkgWriter(m, pkg, info)