4 files changed, 36 insertions, 14 deletions
diff --git a/src/cmd/compile/internal/noder/linker.go b/src/cmd/compile/internal/noder/linker.go
index 51b03a1897..df1e248398 100644
--- a/src/cmd/compile/internal/noder/linker.go
+++ b/src/cmd/compile/internal/noder/linker.go
@@ -338,6 +338,7 @@ func (l *linker) linkname(w *pkgbits.Encoder, name *ir.Name) {
 	linkname := name.Sym().Linkname
 	if !l.lsymIdx(w, linkname, name.Linksym()) {
 		w.String(linkname)
+		w.Bool(name.Linksym().IsLinknameStd())
 	}
 }
 
diff --git a/src/cmd/compile/internal/noder/noder.go b/src/cmd/compile/internal/noder/noder.go
index 973d917784..4e48126e82 100644
--- a/src/cmd/compile/internal/noder/noder.go
+++ b/src/cmd/compile/internal/noder/noder.go
@@ -103,9 +103,10 @@ type noder struct {
 	err        chan syntax.Error
 }
 
-// linkname records a //go:linkname directive.
+// linkname records a //go:linkname or //go:linknamestd directive.
 type linkname struct {
 	pos    syntax.Pos
+	std    bool
 	local  string
 	remote string
 }
@@ -273,10 +274,10 @@ func (p *noder) pragma(pos syntax.Pos, blankLine bool, text string, old syntax.P
 			}
 		}
 
-	case strings.HasPrefix(text, "go:linkname "):
+	case strings.HasPrefix(text, "go:linkname "), strings.HasPrefix(text, "go:linknamestd "):
 		f := strings.Fields(text)
 		if !(2 <= len(f) && len(f) <= 3) {
-			p.error(syntax.Error{Pos: pos, Msg: "usage: //go:linkname localname [linkname]"})
+			p.error(syntax.Error{Pos: pos, Msg: fmt.Sprintf("usage: //%s localname [linkname]", f[0])})
 			break
 		}
 		// The second argument is optional. If omitted, we use
@@ -294,7 +295,7 @@ func (p *noder) pragma(pos syntax.Pos, blankLine bool, text string, old syntax.P
 		} else {
 			panic("missing pkgpath")
 		}
-		p.linknames = append(p.linknames, linkname{pos, f[1], target})
+		p.linknames = append(p.linknames, linkname{pos, f[0] == "go:linknamestd", f[1], target})
 
 	case text == "go:embed", strings.HasPrefix(text, "go:embed "):
 		args, err := parseGoEmbed(text[len("go:embed"):])
diff --git a/src/cmd/compile/internal/noder/reader.go b/src/cmd/compile/internal/noder/reader.go
index 00710775d6..ebb5043a05 100644
--- a/src/cmd/compile/internal/noder/reader.go
+++ b/src/cmd/compile/internal/noder/reader.go
@@ -1277,6 +1277,7 @@ func (r *reader) linkname(name *ir.Name) {
 		lsym.Set(obj.AttrIndexed, true)
 	} else {
 		linkname := r.String()
+		std := r.Bool()
 		sym := name.Sym()
 		sym.Linkname = linkname
 		if sym.Pkg == types.LocalPkg && linkname != "" {
@@ -1286,7 +1287,11 @@ func (r *reader) linkname(name *ir.Name) {
 			// corresponding packages). So we can tell in which package
 			// the linkname is used (pulled), and the linker can
 			// make a decision for allowing or disallowing it.
-			sym.Linksym().Set(obj.AttrLinkname, true)
+			if std {
+				sym.Linksym().Set(obj.AttrLinknameStd, true)
+			} else {
+				sym.Linksym().Set(obj.AttrLinkname, true)
+			}
 		}
 	}
 }
diff --git a/src/cmd/compile/internal/noder/writer.go b/src/cmd/compile/internal/noder/writer.go
index 9e0f4fc9c8..027d7e0636 100644
--- a/src/cmd/compile/internal/noder/writer.go
+++ b/src/cmd/compile/internal/noder/writer.go
@@ -86,8 +86,11 @@ type pkgWriter struct {
 	typDecls map[*types2.TypeName]typeDeclGen
 
 	// linknames maps package-scope objects to their linker symbol name,
-	// if specified by a //go:linkname directive.
-	linknames map[types2.Object]string
+	// if specified by a //go:linkname or //go:linknamestd directive.
+	linknames map[types2.Object]struct {
+		remote string
+		std    bool
+	}
 
 	// cgoPragmas accumulates any //go:cgo_* pragmas that need to be
 	// passed through to cmd/link.
@@ -114,7 +117,10 @@ func newPkgWriter(m posMap, pkg *types2.Package, info *types2.Info, otherInfo ma
 		funDecls: make(map[*types2.Func]*syntax.FuncDecl),
 		typDecls: make(map[*types2.TypeName]typeDeclGen),
 
-		linknames: make(map[types2.Object]string),
+		linknames: make(map[types2.Object]struct {
+			remote string
+			std    bool
+		}),
 	}
 }
 
@@ -1175,7 +1181,9 @@ func (w *writer) varExt(obj *types2.Var) {
 func (w *writer) linkname(obj types2.Object) {
 	w.Sync(pkgbits.SyncLinkname)
 	w.Int64(-1)
-	w.String(w.p.linknames[obj])
+	info := w.p.linknames[obj]
+	w.String(info.remote)
+	w.Bool(info.std)
 }
 
 func (w *writer) pragmaFlag(p ir.PragmaFlag) {
@@ -2799,26 +2807,33 @@ func (pw *pkgWriter) collectDecls(noders []*noder) {
 		pw.cgoPragmas = append(pw.cgoPragmas, p.pragcgobuf...)
 
 		for _, l := range p.linknames {
+			directive := "go:linkname"
+			if l.std {
+				directive = "go:linknamestd"
+			}
 			if !file.importedUnsafe {
-				pw.errorf(l.pos, "//go:linkname only allowed in Go files that import \"unsafe\"")
+				pw.errorf(l.pos, "//%s only allowed in Go files that import \"unsafe\"", directive)
 				continue
 			}
 			if strings.Contains(l.remote, "[") && strings.Contains(l.remote, "]") {
-				pw.errorf(l.pos, "//go:linkname reference of an instantiation is not allowed")
+				pw.errorf(l.pos, "//%s reference of an instantiation is not allowed", directive)
 				continue
 			}
 
 			switch obj := pw.curpkg.Scope().Lookup(l.local).(type) {
 			case *types2.Func, *types2.Var:
 				if _, ok := pw.linknames[obj]; !ok {
-					pw.linknames[obj] = l.remote
+					pw.linknames[obj] = struct {
+						remote string
+						std    bool
+					}{l.remote, l.std}
 				} else {
-					pw.errorf(l.pos, "duplicate //go:linkname for %s", l.local)
+					pw.errorf(l.pos, "duplicate //%s for %s", directive, l.local)
 				}
 
 			default:
 				if types.AllowsGoVersion(1, 18) {
-					pw.errorf(l.pos, "//go:linkname must refer to declared function or variable")
+					pw.errorf(l.pos, "//%s must refer to declared function or variable", directive)
 				}
 			}
 		}