compiler, libgo: change mangling scheme

Overhaul the mangling scheme to avoid ambiguities if the package path
contains a dot. Instead of using dot both to separate components and
to mangle characters, use dot only to separate components and use
underscore to mangle characters.

For golang/go#41862

Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/271726

45 files changed, 341 insertions, 231 deletions

diff --git a/libgo/configure b/libgo/configure
index e7379f8..1d7d007 100755
--- a/libgo/configure
+++ b/libgo/configure
@@ -2551,7 +2551,7 @@ ac_compiler_gnu=$ac_cv_c_compiler_gnu
 ac_config_headers="$ac_config_headers config.h"
 
 
-libtool_VERSION=17:0:0
+libtool_VERSION=18:0:0
 
 
 # Default to --enable-multilib
diff --git a/libgo/configure.ac b/libgo/configure.ac
index 80537f5..5013f41 100644
--- a/libgo/configure.ac
+++ b/libgo/configure.ac
@@ -10,7 +10,7 @@ AC_INIT(package-unused, version-unused,, libgo)
 AC_CONFIG_SRCDIR(Makefile.am)
 AC_CONFIG_HEADER(config.h)
 
-libtool_VERSION=17:0:0
+libtool_VERSION=18:0:0
 AC_SUBST(libtool_VERSION)
 
 AM_ENABLE_MULTILIB(, ..)
diff --git a/libgo/go/cmd/cgo/out.go b/libgo/go/cmd/cgo/out.go
index 2ab8425..0544139 100644
--- a/libgo/go/cmd/cgo/out.go
+++ b/libgo/go/cmd/cgo/out.go
@@ -191,7 +191,7 @@ func (p *Package) writeDefs() {
 			panic(fmt.Errorf("invalid var kind %q", n.Kind))
 		}
 		if *gccgo {
-			fmt.Fprintf(fc, `extern void *%s __asm__("%s.%s");`, n.Mangle, gccgoSymbolPrefix, n.Mangle)
+			fmt.Fprintf(fc, `extern void *%s __asm__("%s.%s");`, n.Mangle, gccgoSymbolPrefix, gccgoToSymbol(n.Mangle))
 			fmt.Fprintf(&gccgoInit, "\t%s = &%s;\n", n.Mangle, n.C)
 			fmt.Fprintf(fc, "\n")
 		}
@@ -1168,7 +1168,7 @@ func (p *Package) writeGccgoExports(fgo2, fm, fgcc, fgcch io.Writer) {
 		// will not be able to link against it from the C
 		// code.
 		goName := "Cgoexp_" + exp.ExpName
-		fmt.Fprintf(fgcc, `extern %s %s %s __asm__("%s.%s");`, cRet, goName, cParams, gccgoSymbolPrefix, goName)
+		fmt.Fprintf(fgcc, `extern %s %s %s __asm__("%s.%s");`, cRet, goName, cParams, gccgoSymbolPrefix, gccgoToSymbol(goName))
 		fmt.Fprint(fgcc, "\n")
 
 		fmt.Fprint(fgcc, "\nCGO_NO_SANITIZE_THREAD\n")
@@ -1202,7 +1202,7 @@ func (p *Package) writeGccgoExports(fgo2, fm, fgcc, fgcch io.Writer) {
 		fmt.Fprint(fgcc, "}\n")
 
 		// Dummy declaration for _cgo_main.c
-		fmt.Fprintf(fm, `char %s[1] __asm__("%s.%s");`, goName, gccgoSymbolPrefix, goName)
+		fmt.Fprintf(fm, `char %s[1] __asm__("%s.%s");`, goName, gccgoSymbolPrefix, gccgoToSymbol(goName))
 		fmt.Fprint(fm, "\n")
 
 		// For gccgo we use a wrapper function in Go, in order
@@ -1286,9 +1286,8 @@ func (p *Package) writeExportHeader(fgcch io.Writer) {
 	fmt.Fprintf(fgcch, "%s\n", p.gccExportHeaderProlog())
 }
 
-// gccgoPkgpathToSymbol converts a package path to a mangled packagepath
-// symbol.
-func gccgoPkgpathToSymbol(ppath string) string {
+// gccgoToSymbol converts a name to a mangled symbol for gccgo.
+func gccgoToSymbol(ppath string) string {
 	if gccgoMangler == nil {
 		var err error
 		cmd := os.Getenv("GCCGO")
@@ -1313,12 +1312,12 @@ func (p *Package) gccgoSymbolPrefix() string {
 	}
 
 	if *gccgopkgpath != "" {
-		return gccgoPkgpathToSymbol(*gccgopkgpath)
+		return gccgoToSymbol(*gccgopkgpath)
 	}
 	if *gccgoprefix == "" && p.PackageName == "main" {
 		return "main"
 	}
-	prefix := gccgoPkgpathToSymbol(*gccgoprefix)
+	prefix := gccgoToSymbol(*gccgoprefix)
 	if prefix == "" {
 		prefix = "go"
 	}
@@ -1710,8 +1709,12 @@ void _cgoPREFIX_Cfunc__Cmalloc(void *v) {
 `
 
 func (p *Package) cPrologGccgo() string {
-	return strings.Replace(strings.Replace(cPrologGccgo, "PREFIX", cPrefix, -1),
-		"GCCGOSYMBOLPREF", p.gccgoSymbolPrefix(), -1)
+	r := strings.NewReplacer(
+		"PREFIX", cPrefix,
+		"GCCGOSYMBOLPREF", p.gccgoSymbolPrefix(),
+		"_cgoCheckPointer", gccgoToSymbol("_cgoCheckPointer"),
+		"_cgoCheckResult", gccgoToSymbol("_cgoCheckResult"))
+	return r.Replace(cPrologGccgo)
 }
 
 const cPrologGccgo = `
diff --git a/libgo/go/cmd/internal/pkgpath/pkgpath.go b/libgo/go/cmd/internal/pkgpath/pkgpath.go
index 0b24468..40a040a 100644
--- a/libgo/go/cmd/internal/pkgpath/pkgpath.go
+++ b/libgo/go/cmd/internal/pkgpath/pkgpath.go
@@ -50,9 +50,12 @@ func ToSymbolFunc(cmd, tmpdir string) (func(string) string, error) {
 		return nil, err
 	}
 
-	// New mangling: expect go.l..u00e4ufer.Run
-	// Old mangling: expect go.l__ufer.Run
-	if bytes.Contains(buf, []byte("go.l..u00e4ufer.Run")) {
+	// Original mangling: go.l__ufer.Run
+	// Mangling v2: go.l..u00e4ufer.Run
+	// Mangling v3: go_0l_u00e4ufer.Run
+	if bytes.Contains(buf, []byte("go_0l_u00e4ufer.Run")) {
+		return toSymbolV3, nil
+	} else if bytes.Contains(buf, []byte("go.l..u00e4ufer.Run")) {
 		return toSymbolV2, nil
 	} else if bytes.Contains(buf, []byte("go.l__ufer.Run")) {
 		return toSymbolV1, nil
@@ -82,7 +85,7 @@ func toSymbolV1(ppath string) string {
 	return strings.Map(clean, ppath)
 }
 
-// toSymbolV2 converts a package path using the newer mangling scheme.
+// toSymbolV2 converts a package path using the second mangling scheme.
 func toSymbolV2(ppath string) string {
 	// This has to build at boostrap time, so it has to build
 	// with Go 1.4, so we don't use strings.Builder.
@@ -112,3 +115,60 @@ func toSymbolV2(ppath string) string {
 	}
 	return string(bsl)
 }
+
+// v3UnderscoreCodes maps from a character that supports an underscore
+// encoding to the underscore encoding character.
+var v3UnderscoreCodes = map[byte]byte{
+	'_': '_',
+	'.': '0',
+	'/': '1',
+	'*': '2',
+	',': '3',
+	'{': '4',
+	'}': '5',
+	'[': '6',
+	']': '7',
+	'(': '8',
+	')': '9',
+	'"': 'a',
+	' ': 'b',
+	';': 'c',
+}
+
+// toSymbolV3 converts a package path using the third mangling scheme.
+func toSymbolV3(ppath string) string {
+	// This has to build at boostrap time, so it has to build
+	// with Go 1.4, so we don't use strings.Builder.
+	bsl := make([]byte, 0, len(ppath))
+	changed := false
+	for _, c := range ppath {
+		if ('A' <= c && c <= 'Z') || ('a' <= c && c <= 'z') || ('0' <= c && c <= '9') {
+			bsl = append(bsl, byte(c))
+			continue
+		}
+
+		if c < 0x80 {
+			if u, ok := v3UnderscoreCodes[byte(c)]; ok {
+				bsl = append(bsl, '_', u)
+				changed = true
+				continue
+			}
+		}
+
+		var enc string
+		switch {
+		case c < 0x80:
+			enc = fmt.Sprintf("_x%02x", c)
+		case c < 0x10000:
+			enc = fmt.Sprintf("_u%04x", c)
+		default:
+			enc = fmt.Sprintf("_U%08x", c)
+		}
+		bsl = append(bsl, enc...)
+		changed = true
+	}
+	if !changed {
+		return ppath
+	}
+	return string(bsl)
+}
diff --git a/libgo/go/cmd/internal/pkgpath/pkgpath_test.go b/libgo/go/cmd/internal/pkgpath/pkgpath_test.go
index 7355f81..232e803 100644
--- a/libgo/go/cmd/internal/pkgpath/pkgpath_test.go
+++ b/libgo/go/cmd/internal/pkgpath/pkgpath_test.go
@@ -24,6 +24,9 @@ func init() {
 	case "v2":
 		os.Stdout.WriteString(`.string	"go.l..u00e4ufer.Run"`)
 		os.Exit(0)
+	case "v3":
+		os.Stdout.WriteString(`.string	"go_0l_u00e4ufer.Run"`)
+		os.Exit(0)
 	case "error":
 		os.Stdout.WriteString(`unknown string`)
 		os.Exit(0)
@@ -46,6 +49,10 @@ func TestToSymbolFunc(t *testing.T) {
 			mangled: "p..u00e4..u4e16..U0001f703",
 		},
 		{
+			env:     "v3",
+			mangled: "p_u00e4_u4e16_U0001f703",
+		},
+		{
 			env:  "error",
 			fail: true,
 		},
@@ -75,32 +82,37 @@ func TestToSymbolFunc(t *testing.T) {
 }
 
 var symbolTests = []struct {
-	input, v1, v2 string
+	input, v1, v2, v3 string
 }{
 	{
 		"",
 		"",
 		"",
+		"",
 	},
 	{
 		"bytes",
 		"bytes",
 		"bytes",
+		"bytes",
 	},
 	{
 		"net/http",
 		"net_http",
 		"net..z2fhttp",
+		"net_1http",
 	},
 	{
 		"golang.org/x/net/http",
 		"golang_org_x_net_http",
 		"golang.x2eorg..z2fx..z2fnet..z2fhttp",
+		"golang_0org_1x_1net_1http",
 	},
 	{
 		"pä世.🜃",
 		"p____",
 		"p..u00e4..u4e16.x2e..U0001f703",
+		"p_u00e4_u4e16_0_U0001f703",
 	},
 }
 
@@ -119,3 +131,11 @@ func TestV2(t *testing.T) {
 		}
 	}
 }
+
+func TestV3(t *testing.T) {
+	for _, test := range symbolTests {
+		if got, want := toSymbolV3(test.input), test.v3; got != want {
+			t.Errorf("toSymbolV3(%q) = %q, want %q", test.input, got, want)
+		}
+	}
+}
diff --git a/libgo/go/go/internal/srcimporter/srcimporter.go b/libgo/go/go/internal/srcimporter/srcimporter.go
index 90bb3a9..3a2ca9a 100644
--- a/libgo/go/go/internal/srcimporter/srcimporter.go
+++ b/libgo/go/go/internal/srcimporter/srcimporter.go
@@ -262,5 +262,5 @@ func (p *Importer) joinPath(elem ...string) string {
 	return filepath.Join(elem...)
 }
 
-//go:linkname setUsesCgo go/types.srcimporter_setUsesCgo
+//go:linkname setUsesCgo go_1types.srcimporter__setUsesCgo
 func setUsesCgo(conf *types.Config)
diff --git a/libgo/go/internal/bytealg/bytealg.c b/libgo/go/internal/bytealg/bytealg.c
index 969732d..6c08340 100644
--- a/libgo/go/internal/bytealg/bytealg.c
+++ b/libgo/go/internal/bytealg/bytealg.c
@@ -38,7 +38,7 @@ static const void *goMemmem(const void *in, size_t inl, const void *s, size_t sl
 #endif
 
 intgo Compare(struct __go_open_array, struct __go_open_array)
-  __asm__(GOSYM_PREFIX "internal..z2fbytealg.Compare")
+  __asm__(GOSYM_PREFIX "internal_1bytealg.Compare")
   __attribute__((no_split_stack));
 
 intgo Compare(struct __go_open_array a, struct __go_open_array b)
@@ -69,7 +69,7 @@ intgo Compare(struct __go_open_array a, struct __go_open_array b)
 }
 
 intgo IndexByte(struct __go_open_array, byte)
-  __asm__(GOSYM_PREFIX "internal..z2fbytealg.IndexByte")
+  __asm__(GOSYM_PREFIX "internal_1bytealg.IndexByte")
   __attribute__((no_split_stack));
 
 intgo IndexByte(struct __go_open_array b, byte c)
@@ -85,7 +85,7 @@ intgo IndexByte(struct __go_open_array b, byte c)
 
 
 intgo IndexByteString(String, byte)
-  __asm__(GOSYM_PREFIX "internal..z2fbytealg.IndexByteString")
+  __asm__(GOSYM_PREFIX "internal_1bytealg.IndexByteString")
   __attribute__((no_split_stack));
 
 intgo IndexByteString(String s, byte c)
@@ -100,7 +100,7 @@ intgo IndexByteString(String s, byte c)
 }
 
 intgo Index(struct __go_open_array, struct __go_open_array)
-  __asm__(GOSYM_PREFIX "internal..z2fbytealg.Index")
+  __asm__(GOSYM_PREFIX "internal_1bytealg.Index")
   __attribute__((no_split_stack));
 
 intgo Index(struct __go_open_array a, struct __go_open_array b)
@@ -115,7 +115,7 @@ intgo Index(struct __go_open_array a, struct __go_open_array b)
 }
 
 intgo IndexString(String, String)
-  __asm__(GOSYM_PREFIX "internal..z2fbytealg.IndexString")
+  __asm__(GOSYM_PREFIX "internal_1bytealg.IndexString")
   __attribute__((no_split_stack));
 
 intgo IndexString(String a, String b)
diff --git a/libgo/go/internal/cpu/cpu_gccgo.c b/libgo/go/internal/cpu/cpu_gccgo.c
index 6b40f01..da26f4d 100644
--- a/libgo/go/internal/cpu/cpu_gccgo.c
+++ b/libgo/go/internal/cpu/cpu_gccgo.c
@@ -21,7 +21,7 @@ struct cpuid_ret {
 };
 
 struct cpuid_ret cpuid(uint32_t, uint32_t)
-  __asm__(GOSYM_PREFIX "internal..z2fcpu.cpuid")
+  __asm__(GOSYM_PREFIX "internal_1cpu.cpuid")
   __attribute__((no_split_stack));
 
 struct cpuid_ret cpuid(uint32_t eaxArg, uint32_t ecxArg) {
@@ -45,7 +45,7 @@ struct xgetbv_ret {
 };
 
 struct xgetbv_ret xgetbv(void)
-  __asm__(GOSYM_PREFIX "internal..z2fcpu.xgetbv")
+  __asm__(GOSYM_PREFIX "internal_1cpu.xgetbv")
   __attribute__((no_split_stack));
 
 #pragma GCC push_options
@@ -82,7 +82,7 @@ struct queryResult {
 };
 
 struct facilityList stfle(void)
-  __asm__(GOSYM_PREFIX "internal..z2fcpu.stfle")
+  __asm__(GOSYM_PREFIX "internal_1cpu.stfle")
   __attribute__((no_split_stack));
 
 struct facilityList stfle(void) {
@@ -96,7 +96,7 @@ struct facilityList stfle(void) {
 }
 
 struct queryResult kmQuery(void)
-  __asm__(GOSYM_PREFIX "internal..z2fcpu.kmQuery")
+  __asm__(GOSYM_PREFIX "internal_1cpu.kmQuery")
   __attribute__((no_split_stack));
 
 struct queryResult kmQuery() {
@@ -110,7 +110,7 @@ struct queryResult kmQuery() {
 }
 
 struct queryResult kmcQuery(void)
-  __asm__(GOSYM_PREFIX "internal..z2fcpu.kmcQuery")
+  __asm__(GOSYM_PREFIX "internal_1cpu.kmcQuery")
   __attribute__((no_split_stack));
 
 struct queryResult kmcQuery() {
@@ -125,7 +125,7 @@ struct queryResult kmcQuery() {
 }
 
 struct queryResult kmctrQuery(void)
-  __asm__(GOSYM_PREFIX "internal..z2fcpu.kmctrQuery")
+  __asm__(GOSYM_PREFIX "internal_1cpu.kmctrQuery")
   __attribute__((no_split_stack));
 
 struct queryResult kmctrQuery() {
@@ -140,7 +140,7 @@ struct queryResult kmctrQuery() {
 }
 
 struct queryResult kmaQuery(void)
-  __asm__(GOSYM_PREFIX "internal..z2fcpu.kmaQuery")
+  __asm__(GOSYM_PREFIX "internal_1cpu.kmaQuery")
   __attribute__((no_split_stack));
 
 struct queryResult kmaQuery() {
@@ -155,7 +155,7 @@ struct queryResult kmaQuery() {
 }
 
 struct queryResult kimdQuery(void)
-  __asm__(GOSYM_PREFIX "internal..z2fcpu.kimdQuery")
+  __asm__(GOSYM_PREFIX "internal_1cpu.kimdQuery")
   __attribute__((no_split_stack));
 
 struct queryResult kimdQuery() {
@@ -170,7 +170,7 @@ struct queryResult kimdQuery() {
 }
 
 struct queryResult klmdQuery(void)
-  __asm__(GOSYM_PREFIX "internal..z2fcpu.klmdQuery")
+  __asm__(GOSYM_PREFIX "internal_1cpu.klmdQuery")
   __attribute__((no_split_stack));
 
 struct queryResult klmdQuery() {
@@ -185,7 +185,7 @@ struct queryResult klmdQuery() {
 }
 
 struct queryResult kdsaQuery(void)
-  __asm__(GOSYM_PREFIX "internal..z2fcpu.kdsaQuery")
+  __asm__(GOSYM_PREFIX "internal_1cpu.kdsaQuery")
   __attribute__((no_split_stack));
 
 struct queryResult kdsaQuery() {
diff --git a/libgo/go/log/syslog/syslog_c.c b/libgo/go/log/syslog/syslog_c.c
index 36e7694..329df40 100644
--- a/libgo/go/log/syslog/syslog_c.c
+++ b/libgo/go/log/syslog/syslog_c.c
@@ -12,7 +12,7 @@
    can't represent a C varargs function in Go.  */
 
 void syslog_c(intgo, const char*)
-  __asm__ (GOSYM_PREFIX "log..z2fsyslog.syslog_c");
+  __asm__ (GOSYM_PREFIX "log_1syslog.syslog_c");
 
 void
 syslog_c (intgo priority, const char *msg)
diff --git a/libgo/go/runtime/atomic_pointer.go b/libgo/go/runtime/atomic_pointer.go
index 49b0f2b..0295913 100644
--- a/libgo/go/runtime/atomic_pointer.go
+++ b/libgo/go/runtime/atomic_pointer.go
@@ -39,10 +39,10 @@ func atomicstorep(ptr unsafe.Pointer, new unsafe.Pointer) {
 // We cannot just call the runtime routines, because the race detector expects
 // to be able to intercept the sync/atomic forms but not the runtime forms.
 
-//go:linkname sync_atomic_StoreUintptr sync..z2fatomic.StoreUintptr
+//go:linkname sync_atomic_StoreUintptr sync_1atomic.StoreUintptr
 func sync_atomic_StoreUintptr(ptr *uintptr, new uintptr)
 
-//go:linkname sync_atomic_StorePointer sync..z2fatomic.StorePointer
+//go:linkname sync_atomic_StorePointer sync_1atomic.StorePointer
 //go:nosplit
 func sync_atomic_StorePointer(ptr *unsafe.Pointer, new unsafe.Pointer) {
 	if writeBarrier.enabled {
@@ -51,10 +51,10 @@ func sync_atomic_StorePointer(ptr *unsafe.Pointer, new unsafe.Pointer) {
 	sync_atomic_StoreUintptr((*uintptr)(unsafe.Pointer(ptr)), uintptr(new))
 }
 
-//go:linkname sync_atomic_SwapUintptr sync..z2fatomic.SwapUintptr
+//go:linkname sync_atomic_SwapUintptr sync_1atomic.SwapUintptr
 func sync_atomic_SwapUintptr(ptr *uintptr, new uintptr) uintptr
 
-//go:linkname sync_atomic_SwapPointer sync..z2fatomic.SwapPointer
+//go:linkname sync_atomic_SwapPointer sync_1atomic.SwapPointer
 //go:nosplit
 func sync_atomic_SwapPointer(ptr *unsafe.Pointer, new unsafe.Pointer) unsafe.Pointer {
 	if writeBarrier.enabled {
@@ -64,10 +64,10 @@ func sync_atomic_SwapPointer(ptr *unsafe.Pointer, new unsafe.Pointer) unsafe.Poi
 	return old
 }
 
-//go:linkname sync_atomic_CompareAndSwapUintptr sync..z2fatomic.CompareAndSwapUintptr
+//go:linkname sync_atomic_CompareAndSwapUintptr sync_1atomic.CompareAndSwapUintptr
 func sync_atomic_CompareAndSwapUintptr(ptr *uintptr, old, new uintptr) bool
 
-//go:linkname sync_atomic_CompareAndSwapPointer sync..z2fatomic.CompareAndSwapPointer
+//go:linkname sync_atomic_CompareAndSwapPointer sync_1atomic.CompareAndSwapPointer
 //go:nosplit
 func sync_atomic_CompareAndSwapPointer(ptr *unsafe.Pointer, old, new unsafe.Pointer) bool {
 	if writeBarrier.enabled {
diff --git a/libgo/go/runtime/chan.go b/libgo/go/runtime/chan.go
index b909d47..8e104f1 100644
--- a/libgo/go/runtime/chan.go
+++ b/libgo/go/runtime/chan.go
@@ -774,7 +774,7 @@ func reflect_chanlen(c *hchan) int {
 	return int(c.qcount)
 }
 
-//go:linkname reflectlite_chanlen internal..z2freflectlite.chanlen
+//go:linkname reflectlite_chanlen internal_1reflectlite.chanlen
 func reflectlite_chanlen(c *hchan) int {
 	if c == nil {
 		return 0
diff --git a/libgo/go/runtime/cpuprof.go b/libgo/go/runtime/cpuprof.go
index d395210..43f0a67 100644
--- a/libgo/go/runtime/cpuprof.go
+++ b/libgo/go/runtime/cpuprof.go
@@ -189,7 +189,7 @@ func CPUProfile() []byte {
 	panic("CPUProfile no longer available")
 }
 
-//go:linkname runtime_pprof_runtime_cyclesPerSecond runtime..z2fpprof.runtime_cyclesPerSecond
+//go:linkname runtime_pprof_runtime_cyclesPerSecond runtime_1pprof.runtime__cyclesPerSecond
 func runtime_pprof_runtime_cyclesPerSecond() int64 {
 	return tickspersecond()
 }
@@ -200,7 +200,7 @@ func runtime_pprof_runtime_cyclesPerSecond() int64 {
 // on has been returned, readProfile returns eof=true.
 // The caller must save the returned data and tags before calling readProfile again.
 //
-//go:linkname runtime_pprof_readProfile runtime..z2fpprof.readProfile
+//go:linkname runtime_pprof_readProfile runtime_1pprof.readProfile
 func runtime_pprof_readProfile() ([]uint64, []unsafe.Pointer, bool) {
 	lock(&cpuprof.lock)
 	log := cpuprof.log
diff --git a/libgo/go/runtime/debug.go b/libgo/go/runtime/debug.go
index 1202e36..ff76580 100644
--- a/libgo/go/runtime/debug.go
+++ b/libgo/go/runtime/debug.go
@@ -66,7 +66,7 @@ func NumGoroutine() int {
 // added.
 func Fieldtrack(map[string]bool)
 
-//go:linkname debug_modinfo runtime..z2fdebug.modinfo
+//go:linkname debug_modinfo runtime_1debug.modinfo
 func debug_modinfo() string {
 	return modinfo
 }
diff --git a/libgo/go/runtime/heapdump.go b/libgo/go/runtime/heapdump.go
index e8f16e9..816d93c 100644
--- a/libgo/go/runtime/heapdump.go
+++ b/libgo/go/runtime/heapdump.go
@@ -16,7 +16,7 @@ import (
 	"unsafe"
 )
 
-//go:linkname runtime_debug_WriteHeapDump runtime..z2fdebug.WriteHeapDump
+//go:linkname runtime_debug_WriteHeapDump runtime_1debug.WriteHeapDump
 func runtime_debug_WriteHeapDump(fd uintptr) {
 	stopTheWorld("write heap dump")
 
diff --git a/libgo/go/runtime/iface.go b/libgo/go/runtime/iface.go
index 5667ddb..f9df1e0 100644
--- a/libgo/go/runtime/iface.go
+++ b/libgo/go/runtime/iface.go
@@ -505,7 +505,7 @@ func reflect_ifaceE2I(inter *interfacetype, e eface, dst *iface) {
 	dst.data = e.data
 }
 
-//go:linkname reflectlite_ifaceE2I internal..z2freflectlite.ifaceE2I
+//go:linkname reflectlite_ifaceE2I internal_1reflectlite.ifaceE2I
 func reflectlite_ifaceE2I(inter *interfacetype, e eface, dst *iface) {
 	t := e._type
 	if t == nil {
diff --git a/libgo/go/runtime/internal/atomic/atomic.c b/libgo/go/runtime/internal/atomic/atomic.c
index 8ae4d7b..9fed1a8 100644
--- a/libgo/go/runtime/internal/atomic/atomic.c
+++ b/libgo/go/runtime/internal/atomic/atomic.c
@@ -7,7 +7,7 @@
 #include "runtime.h"
 
 uint32_t Load (uint32_t *ptr)
-  __asm__ (GOSYM_PREFIX "runtime..z2finternal..z2fatomic.Load")
+  __asm__ (GOSYM_PREFIX "runtime_1internal_1atomic.Load")
   __attribute__ ((no_split_stack));
 
 uint32_t
@@ -17,7 +17,7 @@ Load (uint32_t *ptr)
 }
 
 void *Loadp (void *ptr)
-  __asm__ (GOSYM_PREFIX "runtime..z2finternal..z2fatomic.Loadp")
+  __asm__ (GOSYM_PREFIX "runtime_1internal_1atomic.Loadp")
   __attribute__ ((no_split_stack));
 
 void *
@@ -27,7 +27,7 @@ Loadp (void *ptr)
 }
 
 uint8_t Load8 (uint8_t *ptr)
-  __asm__ (GOSYM_PREFIX "runtime..z2finternal..z2fatomic.Load8")
+  __asm__ (GOSYM_PREFIX "runtime_1internal_1atomic.Load8")
   __attribute__ ((no_split_stack));
 
 uint8_t
@@ -37,7 +37,7 @@ Load8 (uint8_t *ptr)
 }
 
 uint64_t Load64 (uint64_t *ptr)
-  __asm__ (GOSYM_PREFIX "runtime..z2finternal..z2fatomic.Load64")
+  __asm__ (GOSYM_PREFIX "runtime_1internal_1atomic.Load64")
   __attribute__ ((no_split_stack));
 
 uint64_t
@@ -49,7 +49,7 @@ Load64 (uint64_t *ptr)
 }
 
 uint32_t LoadAcq (uint32_t *ptr)
-  __asm__ (GOSYM_PREFIX "runtime..z2finternal..z2fatomic.LoadAcq")
+  __asm__ (GOSYM_PREFIX "runtime_1internal_1atomic.LoadAcq")
   __attribute__ ((no_split_stack));
 
 uint32_t
@@ -59,7 +59,7 @@ LoadAcq (uint32_t *ptr)
 }
 
 uintptr_t Loaduintptr (uintptr_t *ptr)
-  __asm__ (GOSYM_PREFIX "runtime..z2finternal..z2fatomic.Loaduintptr")
+  __asm__ (GOSYM_PREFIX "runtime_1internal_1atomic.Loaduintptr")
   __attribute__ ((no_split_stack));
 
 uintptr_t
@@ -69,7 +69,7 @@ Loaduintptr (uintptr_t *ptr)
 }
 
 uintgo Loaduint (uintgo *ptr)
-  __asm__ (GOSYM_PREFIX "runtime..z2finternal..z2fatomic.Loaduint")
+  __asm__ (GOSYM_PREFIX "runtime_1internal_1atomic.Loaduint")
   __attribute__ ((no_split_stack));
 
 uintgo
@@ -79,7 +79,7 @@ Loaduint (uintgo *ptr)
 }
 
 int64_t Loadint64 (int64_t *ptr)
-  __asm__ (GOSYM_PREFIX "runtime..z2finternal..z2fatomic.Loadint64")
+  __asm__ (GOSYM_PREFIX "runtime_1internal_1atomic.Loadint64")
   __attribute__ ((no_split_stack));
 
 int64_t
@@ -91,7 +91,7 @@ Loadint64 (int64_t *ptr)
 }
 
 uint32_t Xadd (uint32_t *ptr, int32_t delta)
-  __asm__ (GOSYM_PREFIX "runtime..z2finternal..z2fatomic.Xadd")
+  __asm__ (GOSYM_PREFIX "runtime_1internal_1atomic.Xadd")
   __attribute__ ((no_split_stack));
 
 uint32_t
@@ -101,7 +101,7 @@ Xadd (uint32_t *ptr, int32_t delta)
 }
 
 uint64_t Xadd64 (uint64_t *ptr, int64_t delta)
-  __asm__ (GOSYM_PREFIX "runtime..z2finternal..z2fatomic.Xadd64")
+  __asm__ (GOSYM_PREFIX "runtime_1internal_1atomic.Xadd64")
   __attribute__ ((no_split_stack));
 
 uint64_t
@@ -113,7 +113,7 @@ Xadd64 (uint64_t *ptr, int64_t delta)
 }
 
 uintptr_t Xadduintptr (uintptr_t *ptr, uintptr_t delta)
-  __asm__ (GOSYM_PREFIX "runtime..z2finternal..z2fatomic.Xadduintptr")
+  __asm__ (GOSYM_PREFIX "runtime_1internal_1atomic.Xadduintptr")
   __attribute__ ((no_split_stack));
 
 uintptr_t
@@ -123,7 +123,7 @@ Xadduintptr (uintptr_t *ptr, uintptr_t delta)
 }
 
 int64_t Xaddint64 (int64_t *ptr, int64_t delta)
-  __asm__ (GOSYM_PREFIX "runtime..z2finternal..z2fatomic.Xaddint64")
+  __asm__ (GOSYM_PREFIX "runtime_1internal_1atomic.Xaddint64")
   __attribute__ ((no_split_stack));
 
 int64_t
@@ -135,7 +135,7 @@ Xaddint64 (int64_t *ptr, int64_t delta)
 }
 
 uint32_t Xchg (uint32_t *ptr, uint32_t new)
-  __asm__ (GOSYM_PREFIX "runtime..z2finternal..z2fatomic.Xchg")
+  __asm__ (GOSYM_PREFIX "runtime_1internal_1atomic.Xchg")
   __attribute__ ((no_split_stack));
 
 uint32_t
@@ -145,7 +145,7 @@ Xchg (uint32_t *ptr, uint32_t new)
 }
 
 uint64_t Xchg64 (uint64_t *ptr, uint64_t new)
-  __asm__ (GOSYM_PREFIX "runtime..z2finternal..z2fatomic.Xchg64")
+  __asm__ (GOSYM_PREFIX "runtime_1internal_1atomic.Xchg64")
   __attribute__ ((no_split_stack));
 
 uint64_t
@@ -157,7 +157,7 @@ Xchg64 (uint64_t *ptr, uint64_t new)
 }
 
 uintptr_t Xchguintptr (uintptr_t *ptr, uintptr_t new)
-  __asm__ (GOSYM_PREFIX "runtime..z2finternal..z2fatomic.Xchguintptr")
+  __asm__ (GOSYM_PREFIX "runtime_1internal_1atomic.Xchguintptr")
   __attribute__ ((no_split_stack));
 
 uintptr_t
@@ -167,7 +167,7 @@ Xchguintptr (uintptr_t *ptr, uintptr_t new)
 }
 
 void And8 (uint8_t *ptr, uint8_t val)
-  __asm__ (GOSYM_PREFIX "runtime..z2finternal..z2fatomic.And8")
+  __asm__ (GOSYM_PREFIX "runtime_1internal_1atomic.And8")
   __attribute__ ((no_split_stack));
 
 void
@@ -177,7 +177,7 @@ And8 (uint8_t *ptr, uint8_t val)
 }
 
 void Or8 (uint8_t *ptr, uint8_t val)
-  __asm__ (GOSYM_PREFIX "runtime..z2finternal..z2fatomic.Or8")
+  __asm__ (GOSYM_PREFIX "runtime_1internal_1atomic.Or8")
   __attribute__ ((no_split_stack));
 
 void
@@ -187,7 +187,7 @@ Or8 (uint8_t *ptr, uint8_t val)
 }
 
 _Bool Cas (uint32_t *ptr, uint32_t old, uint32_t new)
-  __asm__ (GOSYM_PREFIX "runtime..z2finternal..z2fatomic.Cas")
+  __asm__ (GOSYM_PREFIX "runtime_1internal_1atomic.Cas")
   __attribute__ ((no_split_stack));
 
 _Bool
@@ -197,7 +197,7 @@ Cas (uint32_t *ptr, uint32_t old, uint32_t new)
 }
 
 _Bool Cas64 (uint64_t *ptr, uint64_t old, uint64_t new)
-  __asm__ (GOSYM_PREFIX "runtime..z2finternal..z2fatomic.Cas64")
+  __asm__ (GOSYM_PREFIX "runtime_1internal_1atomic.Cas64")
   __attribute__ ((no_split_stack));
 
 _Bool
@@ -209,7 +209,7 @@ Cas64 (uint64_t *ptr, uint64_t old, uint64_t new)
 }
 
 _Bool CasRel (uint32_t *ptr, uint32_t old, uint32_t new)
-  __asm__ (GOSYM_PREFIX "runtime..z2finternal..z2fatomic.CasRel")
+  __asm__ (GOSYM_PREFIX "runtime_1internal_1atomic.CasRel")
   __attribute__ ((no_split_stack));
 
 _Bool
@@ -219,7 +219,7 @@ CasRel (uint32_t *ptr, uint32_t old, uint32_t new)
 }
 
 _Bool Casp1 (void **ptr, void *old, void *new)
-  __asm__ (GOSYM_PREFIX "runtime..z2finternal..z2fatomic.Casp1")
+  __asm__ (GOSYM_PREFIX "runtime_1internal_1atomic.Casp1")
   __attribute__ ((no_split_stack));
 
 _Bool
@@ -229,7 +229,7 @@ Casp1 (void **ptr, void *old, void *new)
 }
 
 _Bool Casuintptr (uintptr_t *ptr, uintptr_t old, uintptr_t new)
-  __asm__ (GOSYM_PREFIX "runtime..z2finternal..z2fatomic.Casuintptr")
+  __asm__ (GOSYM_PREFIX "runtime_1internal_1atomic.Casuintptr")
   __attribute__ ((no_split_stack));
 
 _Bool
@@ -239,7 +239,7 @@ Casuintptr (uintptr_t *ptr, uintptr_t old, uintptr_t new)
 }
 
 void Store (uint32_t *ptr, uint32_t val)
-  __asm__ (GOSYM_PREFIX "runtime..z2finternal..z2fatomic.Store")
+  __asm__ (GOSYM_PREFIX "runtime_1internal_1atomic.Store")
   __attribute__ ((no_split_stack));
 
 void
@@ -249,7 +249,7 @@ Store (uint32_t *ptr, uint32_t val)
 }
 
 void Store8 (uint8_t *ptr, uint8_t val)
-  __asm__ (GOSYM_PREFIX "runtime..z2finternal..z2fatomic.Store8")
+  __asm__ (GOSYM_PREFIX "runtime_1internal_1atomic.Store8")
   __attribute__ ((no_split_stack));
 
 void
@@ -259,7 +259,7 @@ Store8 (uint8_t *ptr, uint8_t val)
 }
 
 void Store64 (uint64_t *ptr, uint64_t val)
-  __asm__ (GOSYM_PREFIX "runtime..z2finternal..z2fatomic.Store64")
+  __asm__ (GOSYM_PREFIX "runtime_1internal_1atomic.Store64")
   __attribute__ ((no_split_stack));
 
 void
@@ -271,7 +271,7 @@ Store64 (uint64_t *ptr, uint64_t val)
 }
 
 void StoreRel (uint32_t *ptr, uint32_t val)
-  __asm__ (GOSYM_PREFIX "runtime..z2finternal..z2fatomic.StoreRel")
+  __asm__ (GOSYM_PREFIX "runtime_1internal_1atomic.StoreRel")
   __attribute__ ((no_split_stack));
 
 void
@@ -281,7 +281,7 @@ StoreRel (uint32_t *ptr, uint32_t val)
 }
 
 void Storeuintptr (uintptr_t *ptr, uintptr_t val)
-  __asm__ (GOSYM_PREFIX "runtime..z2finternal..z2fatomic.Storeuintptr")
+  __asm__ (GOSYM_PREFIX "runtime_1internal_1atomic.Storeuintptr")
   __attribute__ ((no_split_stack));
 
 void
@@ -291,7 +291,7 @@ Storeuintptr (uintptr_t *ptr, uintptr_t val)
 }
 
 void StorepNoWB (void *ptr, void *val)
-  __asm__ (GOSYM_PREFIX "runtime..z2finternal..z2fatomic.StorepNoWB")
+  __asm__ (GOSYM_PREFIX "runtime_1internal_1atomic.StorepNoWB")
   __attribute__ ((no_split_stack));
 
 void
diff --git a/libgo/go/runtime/malloc.go b/libgo/go/runtime/malloc.go
index 81351ee..feb043a 100644
--- a/libgo/go/runtime/malloc.go
+++ b/libgo/go/runtime/malloc.go
@@ -1220,12 +1220,12 @@ func newobject(typ *_type) unsafe.Pointer {
 	return mallocgc(typ.size, typ, true)
 }
 
-//go:linkname reflect_unsafe_New reflect.unsafe_New
+//go:linkname reflect_unsafe_New reflect.unsafe__New
 func reflect_unsafe_New(typ *_type) unsafe.Pointer {
 	return mallocgc(typ.size, typ, true)
 }
 
-//go:linkname reflectlite_unsafe_New internal..z2freflectlite.unsafe_New
+//go:linkname reflectlite_unsafe_New internal_1reflectlite.unsafe__New
 func reflectlite_unsafe_New(typ *_type) unsafe.Pointer {
 	return mallocgc(typ.size, typ, true)
 }
@@ -1242,7 +1242,7 @@ func newarray(typ *_type, n int) unsafe.Pointer {
 	return mallocgc(mem, typ, true)
 }
 
-//go:linkname reflect_unsafe_NewArray reflect.unsafe_NewArray
+//go:linkname reflect_unsafe_NewArray reflect.unsafe__NewArray
 func reflect_unsafe_NewArray(typ *_type, n int) unsafe.Pointer {
 	return newarray(typ, n)
 }
diff --git a/libgo/go/runtime/map.go b/libgo/go/runtime/map.go
index b829771..1155fee 100644
--- a/libgo/go/runtime/map.go
+++ b/libgo/go/runtime/map.go
@@ -1417,7 +1417,7 @@ func reflect_maplen(h *hmap) int {
 	return h.count
 }
 
-//go:linkname reflectlite_maplen internal..z2freflectlite.maplen
+//go:linkname reflectlite_maplen internal_1reflectlite.maplen
 func reflectlite_maplen(h *hmap) int {
 	if h == nil {
 		return 0
diff --git a/libgo/go/runtime/mbarrier.go b/libgo/go/runtime/mbarrier.go
index 836f85a..3bd8b34 100644
--- a/libgo/go/runtime/mbarrier.go
+++ b/libgo/go/runtime/mbarrier.go
@@ -192,7 +192,7 @@ func reflect_typedmemmove(typ *_type, dst, src unsafe.Pointer) {
 	typedmemmove(typ, dst, src)
 }
 
-//go:linkname reflectlite_typedmemmove internal..z2freflectlite.typedmemmove
+//go:linkname reflectlite_typedmemmove internal_1reflectlite.typedmemmove
 func reflectlite_typedmemmove(typ *_type, dst, src unsafe.Pointer) {
 	reflect_typedmemmove(typ, dst, src)
 }
diff --git a/libgo/go/runtime/mgc.go b/libgo/go/runtime/mgc.go
index 9dd7bff..72479c2 100644
--- a/libgo/go/runtime/mgc.go
+++ b/libgo/go/runtime/mgc.go
@@ -223,7 +223,7 @@ func gcenable() {
 	memstats.enablegc = true // now that runtime is initialized, GC is okay
 }
 
-//go:linkname setGCPercent runtime..z2fdebug.setGCPercent
+//go:linkname setGCPercent runtime_1debug.setGCPercent
 func setGCPercent(in int32) (out int32) {
 	// Run on the system stack since we grab the heap lock.
 	systemstack(func() {
@@ -2238,7 +2238,7 @@ func gcResetMarkState() {
 
 var poolcleanup func()
 
-//go:linkname sync_runtime_registerPoolCleanup sync.runtime_registerPoolCleanup
+//go:linkname sync_runtime_registerPoolCleanup sync.runtime__registerPoolCleanup
 func sync_runtime_registerPoolCleanup(f func()) {
 	poolcleanup = f
 }
diff --git a/libgo/go/runtime/mheap.go b/libgo/go/runtime/mheap.go
index e73ee32..755efd1 100644
--- a/libgo/go/runtime/mheap.go
+++ b/libgo/go/runtime/mheap.go
@@ -1502,7 +1502,7 @@ func (h *mheap) scavengeAll() {
 	}
 }
 
-//go:linkname runtime_debug_freeOSMemory runtime..z2fdebug.freeOSMemory
+//go:linkname runtime_debug_freeOSMemory runtime_1debug.freeOSMemory
 func runtime_debug_freeOSMemory() {
 	GC()
 	systemstack(func() { mheap_.scavengeAll() })
diff --git a/libgo/go/runtime/mprof.go b/libgo/go/runtime/mprof.go
index a4b135d..afacf8f 100644
--- a/libgo/go/runtime/mprof.go
+++ b/libgo/go/runtime/mprof.go
@@ -942,7 +942,7 @@ func ThreadCreateProfile(p []StackRecord) (n int, ok bool) {
 	return
 }
 
-//go:linkname runtime_goroutineProfileWithLabels runtime..z2fpprof.runtime_goroutineProfileWithLabels
+//go:linkname runtime_goroutineProfileWithLabels runtime_1pprof.runtime__goroutineProfileWithLabels
 func runtime_goroutineProfileWithLabels(p []StackRecord, labels []unsafe.Pointer) (n int, ok bool) {
 	return goroutineProfileWithLabels(p, labels)
 }
diff --git a/libgo/go/runtime/mstats.go b/libgo/go/runtime/mstats.go
index 4e2c66ce..85a0861 100644
--- a/libgo/go/runtime/mstats.go
+++ b/libgo/go/runtime/mstats.go
@@ -468,7 +468,7 @@ func readmemstats_m(stats *MemStats) {
 	stats.StackSys += stats.StackInuse
 }
 
-//go:linkname readGCStats runtime..z2fdebug.readGCStats
+//go:linkname readGCStats runtime_1debug.readGCStats
 func readGCStats(pauses *[]uint64) {
 	systemstack(func() {
 		readGCStats_m(pauses)
diff --git a/libgo/go/runtime/net_plan9.go b/libgo/go/runtime/net_plan9.go
index 907c319..38ff5a4 100644
--- a/libgo/go/runtime/net_plan9.go
+++ b/libgo/go/runtime/net_plan9.go
@@ -8,12 +8,12 @@ import (
 	_ "unsafe"
 )
 
-//go:linkname runtime_ignoreHangup internal..z2fpoll.runtime_ignoreHangup
+//go:linkname runtime_ignoreHangup internal_1poll.runtime__ignoreHangup
 func runtime_ignoreHangup() {
 	getg().m.ignoreHangup = true
 }
 
-//go:linkname runtime_unignoreHangup internal..z2fpoll.runtime_unignoreHangup
+//go:linkname runtime_unignoreHangup internal_1poll.runtime__unignoreHangup
 func runtime_unignoreHangup(sig string) {
 	getg().m.ignoreHangup = false
 }
diff --git a/libgo/go/runtime/netpoll.go b/libgo/go/runtime/netpoll.go
index 72a136d..da00b57 100644
--- a/libgo/go/runtime/netpoll.go
+++ b/libgo/go/runtime/netpoll.go
@@ -113,7 +113,7 @@ var (
 	netpollWaiters uint32
 )
 
-//go:linkname poll_runtime_pollServerInit internal..z2fpoll.runtime_pollServerInit
+//go:linkname poll_runtime_pollServerInit internal_1poll.runtime__pollServerInit
 func poll_runtime_pollServerInit() {
 	netpollGenericInit()
 }
@@ -134,7 +134,7 @@ func netpollinited() bool {
 	return atomic.Load(&netpollInited) != 0
 }
 
-//go:linkname poll_runtime_isPollServerDescriptor internal..z2fpoll.runtime_isPollServerDescriptor
+//go:linkname poll_runtime_isPollServerDescriptor internal_1poll.runtime__isPollServerDescriptor
 
 // poll_runtime_isPollServerDescriptor reports whether fd is a
 // descriptor being used by netpoll.
@@ -142,7 +142,7 @@ func poll_runtime_isPollServerDescriptor(fd uintptr) bool {
 	return netpollIsPollDescriptor(fd)
 }
 
-//go:linkname poll_runtime_pollOpen internal..z2fpoll.runtime_pollOpen
+//go:linkname poll_runtime_pollOpen internal_1poll.runtime__pollOpen
 func poll_runtime_pollOpen(fd uintptr) (uintptr, int) {
 	pd := pollcache.alloc()
 	lock(&pd.lock)
@@ -169,7 +169,7 @@ func poll_runtime_pollOpen(fd uintptr) (uintptr, int) {
 	return uintptr(unsafe.Pointer(pd)), int(errno)
 }
 
-//go:linkname poll_runtime_pollClose internal..z2fpoll.runtime_pollClose
+//go:linkname poll_runtime_pollClose internal_1poll.runtime__pollClose
 func poll_runtime_pollClose(ctx uintptr) {
 	pd := (*pollDesc)(unsafe.Pointer(ctx))
 	if !pd.closing {
@@ -195,7 +195,7 @@ func (c *pollCache) free(pd *pollDesc) {
 // poll_runtime_pollReset, which is internal/poll.runtime_pollReset,
 // prepares a descriptor for polling in mode, which is 'r' or 'w'.
 // This returns an error code; the codes are defined above.
-//go:linkname poll_runtime_pollReset internal..z2fpoll.runtime_pollReset
+//go:linkname poll_runtime_pollReset internal_1poll.runtime__pollReset
 func poll_runtime_pollReset(ctx uintptr, mode int) int {
 	pd := (*pollDesc)(unsafe.Pointer(ctx))
 	errcode := netpollcheckerr(pd, int32(mode))
@@ -214,7 +214,7 @@ func poll_runtime_pollReset(ctx uintptr, mode int) int {
 // waits for a descriptor to be ready for reading or writing,
 // according to mode, which is 'r' or 'w'.
 // This returns an error code; the codes are defined above.
-//go:linkname poll_runtime_pollWait internal..z2fpoll.runtime_pollWait
+//go:linkname poll_runtime_pollWait internal_1poll.runtime__pollWait
 func poll_runtime_pollWait(ctx uintptr, mode int) int {
 	pd := (*pollDesc)(unsafe.Pointer(ctx))
 	errcode := netpollcheckerr(pd, int32(mode))
@@ -237,7 +237,7 @@ func poll_runtime_pollWait(ctx uintptr, mode int) int {
 	return pollNoError
 }
 
-//go:linkname poll_runtime_pollWaitCanceled internal..z2fpoll.runtime_pollWaitCanceled
+//go:linkname poll_runtime_pollWaitCanceled internal_1poll.runtime__pollWaitCanceled
 func poll_runtime_pollWaitCanceled(ctx uintptr, mode int) {
 	pd := (*pollDesc)(unsafe.Pointer(ctx))
 	// This function is used only on windows after a failed attempt to cancel
@@ -246,7 +246,7 @@ func poll_runtime_pollWaitCanceled(ctx uintptr, mode int) {
 	}
 }
 
-//go:linkname poll_runtime_pollSetDeadline internal..z2fpoll.runtime_pollSetDeadline
+//go:linkname poll_runtime_pollSetDeadline internal_1poll.runtime__pollSetDeadline
 func poll_runtime_pollSetDeadline(ctx uintptr, d int64, mode int) {
 	pd := (*pollDesc)(unsafe.Pointer(ctx))
 	lock(&pd.lock)
@@ -330,7 +330,7 @@ func poll_runtime_pollSetDeadline(ctx uintptr, d int64, mode int) {
 	}
 }
 
-//go:linkname poll_runtime_pollUnblock internal..z2fpoll.runtime_pollUnblock
+//go:linkname poll_runtime_pollUnblock internal_1poll.runtime__pollUnblock
 func poll_runtime_pollUnblock(ctx uintptr) {
 	pd := (*pollDesc)(unsafe.Pointer(ctx))
 	lock(&pd.lock)
diff --git a/libgo/go/runtime/pprof/mprof_test.go b/libgo/go/runtime/pprof/mprof_test.go
index 625ab7de..83bf572 100644
--- a/libgo/go/runtime/pprof/mprof_test.go
+++ b/libgo/go/runtime/pprof/mprof_test.go
@@ -91,35 +91,35 @@ func TestMemoryProfiler(t *testing.T) {
 		stk    []string
 		legacy string
 	}{{
-		stk: []string{"pprof.allocatePersistent1K", "runtime/pprof.TestMemoryProfiler"},
+		stk: []string{"runtime/pprof.allocatePersistent1K", "runtime/pprof.TestMemoryProfiler"},
 		legacy: fmt.Sprintf(`%v: %v \[%v: %v\] @ 0x[0-9,a-f x]+
-#	0x[0-9,a-f]+	pprof\.allocatePersistent1K\+0x[0-9,a-f]+	.*/mprof_test\.go:47
+#	0x[0-9,a-f]+	runtime/pprof\.allocatePersistent1K\+0x[0-9,a-f]+	.*/mprof_test\.go:47
 #	0x[0-9,a-f]+	runtime/pprof\.TestMemoryProfiler\+0x[0-9,a-f]+	.*/mprof_test\.go:82
 `, 32*memoryProfilerRun, 1024*memoryProfilerRun, 32*memoryProfilerRun, 1024*memoryProfilerRun),
 	}, {
-		stk: []string{"pprof.allocateTransient1M", "runtime/pprof.TestMemoryProfiler"},
+		stk: []string{"runtime/pprof.allocateTransient1M", "runtime/pprof.TestMemoryProfiler"},
 		legacy: fmt.Sprintf(`(0|%v): (0|%v) \[%v: %v\] @ 0x[0-9,a-f x]+
-#	0x[0-9,a-f]+	pprof\.allocateTransient1M\+0x[0-9,a-f]+	.*/mprof_test.go:24
+#	0x[0-9,a-f]+	runtime/pprof\.allocateTransient1M\+0x[0-9,a-f]+	.*/mprof_test.go:24
 #	0x[0-9,a-f]+	runtime/pprof\.TestMemoryProfiler\+0x[0-9,a-f]+	.*/mprof_test.go:79
 `, (1<<10)*memoryProfilerRun, (1<<20)*memoryProfilerRun, (1<<10)*memoryProfilerRun, (1<<20)*memoryProfilerRun),
 	}, {
-		stk: []string{"pprof.allocateTransient2M", "runtime/pprof.TestMemoryProfiler"},
+		stk: []string{"runtime/pprof.allocateTransient2M", "runtime/pprof.TestMemoryProfiler"},
 		// This should start with "0: 0" but gccgo's imprecise
 		// GC means that sometimes the value is not collected.
 		legacy: fmt.Sprintf(`(0|%v): (0|%v) \[%v: %v\] @ 0x[0-9,a-f x]+
-#	0x[0-9,a-f]+	pprof\.allocateTransient2M\+0x[0-9,a-f]+	.*/mprof_test.go:30
+#	0x[0-9,a-f]+	runtime/pprof\.allocateTransient2M\+0x[0-9,a-f]+	.*/mprof_test.go:30
 #	0x[0-9,a-f]+	runtime/pprof\.TestMemoryProfiler\+0x[0-9,a-f]+	.*/mprof_test.go:80
 `, memoryProfilerRun, (2<<20)*memoryProfilerRun, memoryProfilerRun, (2<<20)*memoryProfilerRun),
 	}, {
-		stk: []string{"pprof.allocateTransient2MInline", "runtime/pprof.TestMemoryProfiler"},
+		stk: []string{"runtime/pprof.allocateTransient2MInline", "runtime/pprof.TestMemoryProfiler"},
 		legacy: fmt.Sprintf(`(0|%v): (0|%v) \[%v: %v\] @ 0x[0-9,a-f x]+
-#	0x[0-9,a-f]+	pprof\.allocateTransient2MInline\+0x[0-9,a-f]+	.*/mprof_test.go:34
+#	0x[0-9,a-f]+	runtime/pprof\.allocateTransient2MInline\+0x[0-9,a-f]+	.*/mprof_test.go:34
 #	0x[0-9,a-f]+	runtime/pprof\.TestMemoryProfiler\+0x[0-9,a-f]+	.*/mprof_test.go:81
 `, memoryProfilerRun, (4<<20)*memoryProfilerRun, memoryProfilerRun, (4<<20)*memoryProfilerRun),
 	}, {
-		stk: []string{"pprof.allocateReflectTransient"},
+		stk: []string{"runtime/pprof.allocateReflectTransient"},
 		legacy: fmt.Sprintf(`(0|%v): (0|%v) \[%v: %v\] @( 0x[0-9,a-f]+)+
-#	0x[0-9,a-f]+	pprof\.allocateReflectTransient\+0x[0-9,a-f]+	.*/mprof_test.go:55
+#	0x[0-9,a-f]+	runtime/pprof\.allocateReflectTransient\+0x[0-9,a-f]+	.*/mprof_test.go:55
 `, memoryProfilerRun, (3<<20)*memoryProfilerRun, memoryProfilerRun, (3<<20)*memoryProfilerRun),
 	}}
 
diff --git a/libgo/go/runtime/pprof/pprof_test.go b/libgo/go/runtime/pprof/pprof_test.go
index ff86bce..7adf891 100644
--- a/libgo/go/runtime/pprof/pprof_test.go
+++ b/libgo/go/runtime/pprof/pprof_test.go
@@ -958,8 +958,8 @@ func TestMutexProfile(t *testing.T) {
 
 		stks := stacks(p)
 		for _, want := range [][]string{
-			// {"sync.(*Mutex).Unlock", "pprof.blockMutex.func1"},
-			{"sync.Mutex.Unlock", "pprof.blockMutex..func1"},
+			// {"sync.(*Mutex).Unlock", "runtime/pprof.blockMutex.func1"},
+			{"sync.Mutex.Unlock", "runtime/pprof.blockMutex..func1"},
 		} {
 			if !containsStack(stks, want) {
 				t.Errorf("No matching stack entry for %+v", want)
diff --git a/libgo/go/runtime/preempt.go b/libgo/go/runtime/preempt.go
index 9a78bcf..8452076 100644
--- a/libgo/go/runtime/preempt.go
+++ b/libgo/go/runtime/preempt.go
@@ -360,7 +360,7 @@ func isAsyncSafePoint(gp *g, pc uintptr) (bool, uintptr) {
 	}
 	name := f.Name()
 	if hasPrefix(name, "runtime.") ||
-		hasPrefix(name, "runtime..z2finternal..z2f") ||
+		hasPrefix(name, "runtime_1internal_1") ||
 		hasPrefix(name, "reflect.") {
 		// For now we never async preempt the runtime or
 		// anything closely tied to the runtime. Known issues
diff --git a/libgo/go/runtime/proc.go b/libgo/go/runtime/proc.go
index 0ca6c02..6c72050 100644
--- a/libgo/go/runtime/proc.go
+++ b/libgo/go/runtime/proc.go
@@ -263,7 +263,7 @@ func main(unsafe.Pointer) {
 }
 
 // os_beforeExit is called from os.Exit(0).
-//go:linkname os_beforeExit os.runtime_beforeExit
+//go:linkname os_beforeExit os.runtime__beforeExit
 func os_beforeExit() {
 	if raceenabled {
 		racefini()
@@ -3305,7 +3305,7 @@ func beforefork() {
 }
 
 // Called from syscall package before fork.
-//go:linkname syscall_runtime_BeforeFork syscall.runtime_BeforeFork
+//go:linkname syscall_runtime_BeforeFork syscall.runtime__BeforeFork
 //go:nosplit
 func syscall_runtime_BeforeFork() {
 	systemstack(beforefork)
@@ -3320,7 +3320,7 @@ func afterfork() {
 }
 
 // Called from syscall package after fork in parent.
-//go:linkname syscall_runtime_AfterFork syscall.runtime_AfterFork
+//go:linkname syscall_runtime_AfterFork syscall.runtime__AfterFork
 //go:nosplit
 func syscall_runtime_AfterFork() {
 	systemstack(afterfork)
@@ -3338,7 +3338,7 @@ var inForkedChild bool
 // temporarily sharing address space with the parent process, this must
 // not change any global variables or calling into C code that may do so.
 //
-//go:linkname syscall_runtime_AfterForkInChild syscall.runtime_AfterForkInChild
+//go:linkname syscall_runtime_AfterForkInChild syscall.runtime__AfterForkInChild
 //go:nosplit
 //go:nowritebarrierrec
 func syscall_runtime_AfterForkInChild() {
@@ -3363,7 +3363,7 @@ func syscall_runtime_AfterForkInChild() {
 var pendingPreemptSignals uint32
 
 // Called from syscall package before Exec.
-//go:linkname syscall_runtime_BeforeExec syscall.runtime_BeforeExec
+//go:linkname syscall_runtime_BeforeExec syscall.runtime__BeforeExec
 func syscall_runtime_BeforeExec() {
 	// Prevent thread creation during exec.
 	execLock.lock()
@@ -3378,7 +3378,7 @@ func syscall_runtime_BeforeExec() {
 }
 
 // Called from syscall package after Exec.
-//go:linkname syscall_runtime_AfterExec syscall.runtime_AfterExec
+//go:linkname syscall_runtime_AfterExec syscall.runtime__AfterExec
 func syscall_runtime_AfterExec() {
 	execLock.unlock()
 }
@@ -5165,7 +5165,7 @@ func (l *gList) pop() *g {
 	return gp
 }
 
-//go:linkname setMaxThreads runtime..z2fdebug.setMaxThreads
+//go:linkname setMaxThreads runtime_1debug.setMaxThreads
 func setMaxThreads(in int) (out int) {
 	lock(&sched.lock)
 	out = int(sched.maxmcount)
@@ -5199,32 +5199,32 @@ func procUnpin() {
 	_g_.m.locks--
 }
 
-//go:linkname sync_runtime_procPin sync.runtime_procPin
+//go:linkname sync_runtime_procPin sync.runtime__procPin
 //go:nosplit
 func sync_runtime_procPin() int {
 	return procPin()
 }
 
-//go:linkname sync_runtime_procUnpin sync.runtime_procUnpin
+//go:linkname sync_runtime_procUnpin sync.runtime__procUnpin
 //go:nosplit
 func sync_runtime_procUnpin() {
 	procUnpin()
 }
 
-//go:linkname sync_atomic_runtime_procPin sync..z2fatomic.runtime_procPin
+//go:linkname sync_atomic_runtime_procPin sync_1atomic.runtime__procPin
 //go:nosplit
 func sync_atomic_runtime_procPin() int {
 	return procPin()
 }
 
-//go:linkname sync_atomic_runtime_procUnpin sync..z2fatomic.runtime_procUnpin
+//go:linkname sync_atomic_runtime_procUnpin sync_1atomic.runtime__procUnpin
 //go:nosplit
 func sync_atomic_runtime_procUnpin() {
 	procUnpin()
 }
 
 // Active spinning for sync.Mutex.
-//go:linkname sync_runtime_canSpin sync.runtime_canSpin
+//go:linkname sync_runtime_canSpin sync.runtime__canSpin
 //go:nosplit
 func sync_runtime_canSpin(i int) bool {
 	// sync.Mutex is cooperative, so we are conservative with spinning.
@@ -5241,7 +5241,7 @@ func sync_runtime_canSpin(i int) bool {
 	return true
 }
 
-//go:linkname sync_runtime_doSpin sync.runtime_doSpin
+//go:linkname sync_runtime_doSpin sync.runtime__doSpin
 //go:nosplit
 func sync_runtime_doSpin() {
 	procyield(active_spin_cnt)
diff --git a/libgo/go/runtime/proflabel.go b/libgo/go/runtime/proflabel.go
index fc655cc..1e1f3bf 100644
--- a/libgo/go/runtime/proflabel.go
+++ b/libgo/go/runtime/proflabel.go
@@ -8,7 +8,7 @@ import "unsafe"
 
 var labelSync uintptr
 
-//go:linkname runtime_setProfLabel runtime..z2fpprof.runtime_setProfLabel
+//go:linkname runtime_setProfLabel runtime_1pprof.runtime__setProfLabel
 func runtime_setProfLabel(labels unsafe.Pointer) {
 	// Introduce race edge for read-back via profile.
 	// This would more properly use &getg().labels as the sync address,
@@ -34,7 +34,7 @@ func runtime_setProfLabel(labels unsafe.Pointer) {
 	getg().labels = labels
 }
 
-//go:linkname runtime_getProfLabel runtime..z2fpprof.runtime_getProfLabel
+//go:linkname runtime_getProfLabel runtime_1pprof.runtime__getProfLabel
 func runtime_getProfLabel() unsafe.Pointer {
 	return getg().labels
 }
diff --git a/libgo/go/runtime/rdebug.go b/libgo/go/runtime/rdebug.go
index 358df11..9c43ce5 100644
--- a/libgo/go/runtime/rdebug.go
+++ b/libgo/go/runtime/rdebug.go
@@ -11,14 +11,14 @@ import _ "unsafe" // for go:linkname
 // maxstacksize.
 var maxstacksize uintptr = 1 << 20 // enough until runtime.main sets it for real
 
-//go:linkname setMaxStack runtime..z2fdebug.setMaxStack
+//go:linkname setMaxStack runtime_1debug.setMaxStack
 func setMaxStack(in int) (out int) {
 	out = int(maxstacksize)
 	maxstacksize = uintptr(in)
 	return out
 }
 
-//go:linkname setPanicOnFault runtime..z2fdebug.setPanicOnFault
+//go:linkname setPanicOnFault runtime_1debug.setPanicOnFault
 func setPanicOnFault(new bool) (old bool) {
 	_g_ := getg()
 	old = _g_.paniconfault
diff --git a/libgo/go/runtime/runtime.go b/libgo/go/runtime/runtime.go
index abc5eab..5af28ae 100644
--- a/libgo/go/runtime/runtime.go
+++ b/libgo/go/runtime/runtime.go
@@ -51,13 +51,13 @@ func tickspersecond() int64 {
 var envs []string
 var argslice []string
 
-//go:linkname syscall_runtime_envs syscall.runtime_envs
+//go:linkname syscall_runtime_envs syscall.runtime__envs
 func syscall_runtime_envs() []string { return append([]string{}, envs...) }
 
 //go:linkname syscall_Getpagesize syscall.Getpagesize
 func syscall_Getpagesize() int { return int(physPageSize) }
 
-//go:linkname os_runtime_args os.runtime_args
+//go:linkname os_runtime_args os.runtime__args
 func os_runtime_args() []string { return append([]string{}, argslice...) }
 
 //go:linkname syscall_Exit syscall.Exit
diff --git a/libgo/go/runtime/runtime1.go b/libgo/go/runtime/runtime1.go
index a8a53d3..39969d1 100644
--- a/libgo/go/runtime/runtime1.go
+++ b/libgo/go/runtime/runtime1.go
@@ -398,7 +398,7 @@ func parsedebugvars() {
 	traceback_env = traceback_cache
 }
 
-//go:linkname setTraceback runtime..z2fdebug.SetTraceback
+//go:linkname setTraceback runtime_1debug.SetTraceback
 func setTraceback(level string) {
 	var t uint32
 	switch level {
diff --git a/libgo/go/runtime/sema.go b/libgo/go/runtime/sema.go
index c1418b3..9a28880 100644
--- a/libgo/go/runtime/sema.go
+++ b/libgo/go/runtime/sema.go
@@ -51,27 +51,27 @@ var semtable [semTabSize]struct {
 	pad  [cpu.CacheLinePadSize - unsafe.Sizeof(semaRoot{})]byte
 }
 
-//go:linkname sync_runtime_Semacquire sync.runtime_Semacquire
+//go:linkname sync_runtime_Semacquire sync.runtime__Semacquire
 func sync_runtime_Semacquire(addr *uint32) {
 	semacquire1(addr, false, semaBlockProfile, 0)
 }
 
-//go:linkname poll_runtime_Semacquire internal..z2fpoll.runtime_Semacquire
+//go:linkname poll_runtime_Semacquire internal_1poll.runtime__Semacquire
 func poll_runtime_Semacquire(addr *uint32) {
 	semacquire1(addr, false, semaBlockProfile, 0)
 }
 
-//go:linkname sync_runtime_Semrelease sync.runtime_Semrelease
+//go:linkname sync_runtime_Semrelease sync.runtime__Semrelease
 func sync_runtime_Semrelease(addr *uint32, handoff bool, skipframes int) {
 	semrelease1(addr, handoff, skipframes)
 }
 
-//go:linkname sync_runtime_SemacquireMutex sync.runtime_SemacquireMutex
+//go:linkname sync_runtime_SemacquireMutex sync.runtime__SemacquireMutex
 func sync_runtime_SemacquireMutex(addr *uint32, lifo bool, skipframes int) {
 	semacquire1(addr, lifo, semaBlockProfile|semaMutexProfile, skipframes)
 }
 
-//go:linkname poll_runtime_Semrelease internal..z2fpoll.runtime_Semrelease
+//go:linkname poll_runtime_Semrelease internal_1poll.runtime__Semrelease
 func poll_runtime_Semrelease(addr *uint32) {
 	semrelease(addr)
 }
@@ -475,7 +475,7 @@ func less(a, b uint32) bool {
 // notifyListAdd adds the caller to a notify list such that it can receive
 // notifications. The caller must eventually call notifyListWait to wait for
 // such a notification, passing the returned ticket number.
-//go:linkname notifyListAdd sync.runtime_notifyListAdd
+//go:linkname notifyListAdd sync.runtime__notifyListAdd
 func notifyListAdd(l *notifyList) uint32 {
 	// This may be called concurrently, for example, when called from
 	// sync.Cond.Wait while holding a RWMutex in read mode.
@@ -484,7 +484,7 @@ func notifyListAdd(l *notifyList) uint32 {
 
 // notifyListWait waits for a notification. If one has been sent since
 // notifyListAdd was called, it returns immediately. Otherwise, it blocks.
-//go:linkname notifyListWait sync.runtime_notifyListWait
+//go:linkname notifyListWait sync.runtime__notifyListWait
 func notifyListWait(l *notifyList, t uint32) {
 	lockWithRank(&l.lock, lockRankNotifyList)
 
@@ -518,7 +518,7 @@ func notifyListWait(l *notifyList, t uint32) {
 }
 
 // notifyListNotifyAll notifies all entries in the list.
-//go:linkname notifyListNotifyAll sync.runtime_notifyListNotifyAll
+//go:linkname notifyListNotifyAll sync.runtime__notifyListNotifyAll
 func notifyListNotifyAll(l *notifyList) {
 	// Fast-path: if there are no new waiters since the last notification
 	// we don't need to acquire the lock.
@@ -550,7 +550,7 @@ func notifyListNotifyAll(l *notifyList) {
 }
 
 // notifyListNotifyOne notifies one entry in the list.
-//go:linkname notifyListNotifyOne sync.runtime_notifyListNotifyOne
+//go:linkname notifyListNotifyOne sync.runtime__notifyListNotifyOne
 func notifyListNotifyOne(l *notifyList) {
 	// Fast-path: if there are no new waiters since the last notification
 	// we don't need to acquire the lock at all.
@@ -603,7 +603,7 @@ func notifyListNotifyOne(l *notifyList) {
 	unlock(&l.lock)
 }
 
-//go:linkname notifyListCheck sync.runtime_notifyListCheck
+//go:linkname notifyListCheck sync.runtime__notifyListCheck
 func notifyListCheck(sz uintptr) {
 	if sz != unsafe.Sizeof(notifyList{}) {
 		print("runtime: bad notifyList size - sync=", sz, " runtime=", unsafe.Sizeof(notifyList{}), "\n")
@@ -611,7 +611,7 @@ func notifyListCheck(sz uintptr) {
 	}
 }
 
-//go:linkname sync_nanotime sync.runtime_nanotime
+//go:linkname sync_nanotime sync.runtime__nanotime
 func sync_nanotime() int64 {
 	return nanotime()
 }
diff --git a/libgo/go/runtime/sigqueue.go b/libgo/go/runtime/sigqueue.go
index 7d1028e..ed024e1 100644
--- a/libgo/go/runtime/sigqueue.go
+++ b/libgo/go/runtime/sigqueue.go
@@ -121,7 +121,7 @@ Send:
 
 // Called to receive the next queued signal.
 // Must only be called from a single goroutine at a time.
-//go:linkname signal_recv os..z2fsignal.signal_recv
+//go:linkname signal_recv os_1signal.signal__recv
 func signal_recv() uint32 {
 	for {
 		// Serve any signals from local copy.
@@ -169,7 +169,7 @@ func signal_recv() uint32 {
 // the signal(s) in question, and here we are just waiting to make sure
 // that all the signals have been delivered to the user channels
 // by the os/signal package.
-//go:linkname signalWaitUntilIdle os..z2fsignal.signalWaitUntilIdle
+//go:linkname signalWaitUntilIdle os_1signal.signalWaitUntilIdle
 func signalWaitUntilIdle() {
 	// Although the signals we care about have been removed from
 	// sig.wanted, it is possible that another thread has received
@@ -189,7 +189,7 @@ func signalWaitUntilIdle() {
 }
 
 // Must only be called from a single goroutine at a time.
-//go:linkname signal_enable os..z2fsignal.signal_enable
+//go:linkname signal_enable os_1signal.signal__enable
 func signal_enable(s uint32) {
 	if !sig.inuse {
 		// This is the first call to signal_enable. Initialize.
@@ -217,7 +217,7 @@ func signal_enable(s uint32) {
 }
 
 // Must only be called from a single goroutine at a time.
-//go:linkname signal_disable os..z2fsignal.signal_disable
+//go:linkname signal_disable os_1signal.signal__disable
 func signal_disable(s uint32) {
 	if s >= uint32(len(sig.wanted)*32) {
 		return
@@ -230,7 +230,7 @@ func signal_disable(s uint32) {
 }
 
 // Must only be called from a single goroutine at a time.
-//go:linkname signal_ignore os..z2fsignal.signal_ignore
+//go:linkname signal_ignore os_1signal.signal__ignore
 func signal_ignore(s uint32) {
 	if s >= uint32(len(sig.wanted)*32) {
 		return
@@ -257,7 +257,7 @@ func sigInitIgnored(s uint32) {
 }
 
 // Checked by signal handlers.
-//go:linkname signal_ignored os..z2fsignal.signal_ignored
+//go:linkname signal_ignored os_1signal.signal__ignored
 func signal_ignored(s uint32) bool {
 	i := atomic.Load(&sig.ignored[s/32])
 	return i&(1<<(s&31)) != 0
diff --git a/libgo/go/runtime/symtab.go b/libgo/go/runtime/symtab.go
index bb0b61d..22a2b13 100644
--- a/libgo/go/runtime/symtab.go
+++ b/libgo/go/runtime/symtab.go
@@ -5,6 +5,7 @@
 package runtime
 
 import (
+	"internal/bytealg"
 	_ "unsafe" // for go:linkname
 )
 
@@ -119,7 +120,7 @@ func pcInlineCallers(pc uintptr, locbuf *location, max int32) int32
 // runtime_expandFinalInlineFrame expands the final pc in stk to include all
 // "callers" if pc is inline.
 //
-//go:linkname runtime_expandFinalInlineFrame runtime..z2fpprof.runtime_expandFinalInlineFrame
+//go:linkname runtime_expandFinalInlineFrame runtime_1pprof.runtime__expandFinalInlineFrame
 func runtime_expandFinalInlineFrame(stk []uintptr) []uintptr {
 	if len(stk) == 0 {
 		return stk
@@ -210,42 +211,62 @@ func hexDigitsToRune(digits []byte, ndig int) rune {
 	return rune(result)
 }
 
-// Perform an in-place decoding on the input byte slice. This looks
-// for "..z<hex 2 >", "..u<hex x 4>" and "..U<hex x 8>" and overwrites
-// with the encoded bytes corresponding to the unicode in question.
-// Return value is the number of bytes taken by the result.
-
+// decodeIdentifier performs an in-place decoding on the input byte slice.
+// This undoes the compiler underscore mangling.
+// Returns the number of bytes used by the result.
 func decodeIdentifier(bsl []byte) int {
+	underscoreCodes := map[byte]byte{
+		'_': '_',
+		'0': '.',
+		'1': '/',
+		'2': '*',
+		'3': ',',
+		'4': '{',
+		'5': '}',
+		'6': '[',
+		'7': ']',
+		'8': '(',
+		'9': ')',
+		'a': '"',
+		'b': ' ',
+		'c': ';',
+	}
+
 	j := 0
 	for i := 0; i < len(bsl); i++ {
 		b := bsl[i]
+		if b != '_' || i+1 >= len(bsl) {
+			bsl[j] = b
+			j++
+			continue
+		}
+
+		if d, ok := underscoreCodes[bsl[i+1]]; ok {
+			i++
+			bsl[j] = d
+			j++
+			continue
+		}
+
+		rlen := 0
+		switch bsl[i+1] {
+		case 'x':
+			rlen = 2
+		case 'u':
+			rlen = 4
+		case 'U':
+			rlen = 8
+		}
 
-		if i+1 < len(bsl) && bsl[i] == '.' && bsl[i+1] == '.' {
-			if i+4 < len(bsl) && bsl[i+2] == 'z' {
-				digits := bsl[i+3:]
-				r := hexDigitsToRune(digits, 2)
-				nc := encoderune(bsl[j:], r)
-				j += nc
-				i += 4
-				continue
-			} else if i+6 < len(bsl) && bsl[i+2] == 'u' {
-				digits := bsl[i+3:]
-				r := hexDigitsToRune(digits, 4)
-				nc := encoderune(bsl[j:], r)
-				j += nc
-				i += 6
-				continue
-			} else if i+10 < len(bsl) && bsl[i+2] == 'U' {
-				digits := bsl[i+3:]
-				r := hexDigitsToRune(digits, 8)
-				nc := encoderune(bsl[j:], r)
-				j += nc
-				i += 10
-				continue
-			}
+		if rlen > 0 && i+1+rlen < len(bsl) {
+			r := hexDigitsToRune(bsl[i+2:], rlen)
+			nc := encoderune(bsl[j:], r)
+			j += nc
+			i += rlen + 1
+		} else {
+			bsl[j] = b
+			j++
 		}
-		bsl[j] = b
-		j += 1
 	}
 	return j
 }
@@ -254,6 +275,11 @@ func decodeIdentifier(bsl []byte) int {
 // as used in the compiler.
 
 func demangleSymbol(s string) string {
+	if bytealg.IndexByteString(s, '.') < 0 {
+		// A symbol with no '.' is not a Go symbol.
+		return s
+	}
+
 	bsl := []byte(s)
 	nchars := decodeIdentifier(bsl)
 	bsl = bsl[:nchars]
diff --git a/libgo/go/runtime/trace.go b/libgo/go/runtime/trace.go
index ce185fc..b05f30a 100644
--- a/libgo/go/runtime/trace.go
+++ b/libgo/go/runtime/trace.go
@@ -1152,7 +1152,7 @@ func traceNextGC() {
 // To access runtime functions from runtime/trace.
 // See runtime/trace/annotation.go
 
-//go:linkname trace_userTaskCreate runtime..z2ftrace.userTaskCreate
+//go:linkname trace_userTaskCreate runtime_1trace.userTaskCreate
 func trace_userTaskCreate(id, parentID uint64, taskType string) {
 	if !trace.enabled {
 		return
@@ -1170,12 +1170,12 @@ func trace_userTaskCreate(id, parentID uint64, taskType string) {
 	traceReleaseBuffer(pid)
 }
 
-//go:linkname trace_userTaskEnd runtime..z2ftrace.userTaskEnd
+//go:linkname trace_userTaskEnd runtime_1trace.userTaskEnd
 func trace_userTaskEnd(id uint64) {
 	traceEvent(traceEvUserTaskEnd, 2, id)
 }
 
-//go:linkname trace_userRegion runtime..z2ftrace.userRegion
+//go:linkname trace_userRegion runtime_1trace.userRegion
 func trace_userRegion(id, mode uint64, name string) {
 	if !trace.enabled {
 		return
@@ -1192,7 +1192,7 @@ func trace_userRegion(id, mode uint64, name string) {
 	traceReleaseBuffer(pid)
 }
 
-//go:linkname trace_userLog runtime..z2ftrace.userLog
+//go:linkname trace_userLog runtime_1trace.userLog
 func trace_userLog(id uint64, category, message string) {
 	if !trace.enabled {
 		return
diff --git a/libgo/go/runtime/traceback_gccgo.go b/libgo/go/runtime/traceback_gccgo.go
index 1ba91af..ebdbefc 100644
--- a/libgo/go/runtime/traceback_gccgo.go
+++ b/libgo/go/runtime/traceback_gccgo.go
@@ -184,10 +184,10 @@ func showfuncinfo(name string, firstFrame bool) bool {
 // isExportedRuntime reports whether name is an exported runtime function.
 // It is only for runtime functions, so ASCII A-Z is fine. Here also check
 // for mangled functions from runtime/<...>, which will be prefixed with
-// "runtime..z2f".
+// "runtime_1".
 func isExportedRuntime(name string) bool {
 	const n = len("runtime.")
-	if hasPrefix(name, "runtime..z2f") {
+	if hasPrefix(name, "runtime_1") {
 		return true
 	}
 	return len(name) > n && name[:n] == "runtime." && 'A' <= name[n] && name[n] <= 'Z'
diff --git a/libgo/go/sync/atomic/atomic.c b/libgo/go/sync/atomic/atomic.c
index 90a4ff3..71d51aa 100644
--- a/libgo/go/sync/atomic/atomic.c
+++ b/libgo/go/sync/atomic/atomic.c
@@ -9,7 +9,7 @@
 #include "runtime.h"
 
 int32_t SwapInt32 (int32_t *, int32_t)
-  __asm__ (GOSYM_PREFIX "sync..z2fatomic.SwapInt32")
+  __asm__ (GOSYM_PREFIX "sync_1atomic.SwapInt32")
   __attribute__ ((no_split_stack));
 
 int32_t
@@ -19,7 +19,7 @@ SwapInt32 (int32_t *addr, int32_t new)
 }
 
 int64_t SwapInt64 (int64_t *, int64_t)
-  __asm__ (GOSYM_PREFIX "sync..z2fatomic.SwapInt64")
+  __asm__ (GOSYM_PREFIX "sync_1atomic.SwapInt64")
   __attribute__ ((no_split_stack));
 
 int64_t
@@ -31,7 +31,7 @@ SwapInt64 (int64_t *addr, int64_t new)
 }
 
 uint32_t SwapUint32 (uint32_t *, uint32_t)
-  __asm__ (GOSYM_PREFIX "sync..z2fatomic.SwapUint32")
+  __asm__ (GOSYM_PREFIX "sync_1atomic.SwapUint32")
   __attribute__ ((no_split_stack));
 
 uint32_t
@@ -41,7 +41,7 @@ SwapUint32 (uint32_t *addr, uint32_t new)
 }
 
 uint64_t SwapUint64 (uint64_t *, uint64_t)
-  __asm__ (GOSYM_PREFIX "sync..z2fatomic.SwapUint64")
+  __asm__ (GOSYM_PREFIX "sync_1atomic.SwapUint64")
   __attribute__ ((no_split_stack));
 
 uint64_t
@@ -53,7 +53,7 @@ SwapUint64 (uint64_t *addr, uint64_t new)
 }
 
 uintptr_t SwapUintptr (uintptr_t *, uintptr_t)
-  __asm__ (GOSYM_PREFIX "sync..z2fatomic.SwapUintptr")
+  __asm__ (GOSYM_PREFIX "sync_1atomic.SwapUintptr")
   __attribute__ ((no_split_stack));
 
 uintptr_t
@@ -63,7 +63,7 @@ SwapUintptr (uintptr_t *addr, uintptr_t new)
 }
 
 _Bool CompareAndSwapInt32 (int32_t *, int32_t, int32_t)
-  __asm__ (GOSYM_PREFIX "sync..z2fatomic.CompareAndSwapInt32")
+  __asm__ (GOSYM_PREFIX "sync_1atomic.CompareAndSwapInt32")
   __attribute__ ((no_split_stack));
 
 _Bool
@@ -74,7 +74,7 @@ CompareAndSwapInt32 (int32_t *val, int32_t old, int32_t new)
 }
 
 _Bool CompareAndSwapInt64 (int64_t *, int64_t, int64_t)
-  __asm__ (GOSYM_PREFIX "sync..z2fatomic.CompareAndSwapInt64")
+  __asm__ (GOSYM_PREFIX "sync_1atomic.CompareAndSwapInt64")
   __attribute__ ((no_split_stack));
 
 _Bool
@@ -87,7 +87,7 @@ CompareAndSwapInt64 (int64_t *val, int64_t old, int64_t new)
 }
 
 _Bool CompareAndSwapUint32 (uint32_t *, uint32_t, uint32_t)
-  __asm__ (GOSYM_PREFIX "sync..z2fatomic.CompareAndSwapUint32")
+  __asm__ (GOSYM_PREFIX "sync_1atomic.CompareAndSwapUint32")
   __attribute__ ((no_split_stack));
 
 _Bool
@@ -98,7 +98,7 @@ CompareAndSwapUint32 (uint32_t *val, uint32_t old, uint32_t new)
 }
 
 _Bool CompareAndSwapUint64 (uint64_t *, uint64_t, uint64_t)
-  __asm__ (GOSYM_PREFIX "sync..z2fatomic.CompareAndSwapUint64")
+  __asm__ (GOSYM_PREFIX "sync_1atomic.CompareAndSwapUint64")
   __attribute__ ((no_split_stack));
 
 _Bool
@@ -111,7 +111,7 @@ CompareAndSwapUint64 (uint64_t *val, uint64_t old, uint64_t new)
 }
 
 _Bool CompareAndSwapUintptr (uintptr_t *, uintptr_t, uintptr_t)
-  __asm__ (GOSYM_PREFIX "sync..z2fatomic.CompareAndSwapUintptr")
+  __asm__ (GOSYM_PREFIX "sync_1atomic.CompareAndSwapUintptr")
   __attribute__ ((no_split_stack));
 
 _Bool
@@ -122,7 +122,7 @@ CompareAndSwapUintptr (uintptr_t *val, uintptr_t old, uintptr_t new)
 }
 
 int32_t AddInt32 (int32_t *, int32_t)
-  __asm__ (GOSYM_PREFIX "sync..z2fatomic.AddInt32")
+  __asm__ (GOSYM_PREFIX "sync_1atomic.AddInt32")
   __attribute__ ((no_split_stack));
 
 int32_t
@@ -132,7 +132,7 @@ AddInt32 (int32_t *val, int32_t delta)
 }
 
 uint32_t AddUint32 (uint32_t *, uint32_t)
-  __asm__ (GOSYM_PREFIX "sync..z2fatomic.AddUint32")
+  __asm__ (GOSYM_PREFIX "sync_1atomic.AddUint32")
   __attribute__ ((no_split_stack));
 
 uint32_t
@@ -142,7 +142,7 @@ AddUint32 (uint32_t *val, uint32_t delta)
 }
 
 int64_t AddInt64 (int64_t *, int64_t)
-  __asm__ (GOSYM_PREFIX "sync..z2fatomic.AddInt64")
+  __asm__ (GOSYM_PREFIX "sync_1atomic.AddInt64")
   __attribute__ ((no_split_stack));
 
 int64_t
@@ -154,7 +154,7 @@ AddInt64 (int64_t *val, int64_t delta)
 }
 
 uint64_t AddUint64 (uint64_t *, uint64_t)
-  __asm__ (GOSYM_PREFIX "sync..z2fatomic.AddUint64")
+  __asm__ (GOSYM_PREFIX "sync_1atomic.AddUint64")
   __attribute__ ((no_split_stack));
 
 uint64_t
@@ -166,7 +166,7 @@ AddUint64 (uint64_t *val, uint64_t delta)
 }
 
 uintptr_t AddUintptr (uintptr_t *, uintptr_t)
-  __asm__ (GOSYM_PREFIX "sync..z2fatomic.AddUintptr")
+  __asm__ (GOSYM_PREFIX "sync_1atomic.AddUintptr")
   __attribute__ ((no_split_stack));
 
 uintptr_t
@@ -176,7 +176,7 @@ AddUintptr (uintptr_t *val, uintptr_t delta)
 }
 
 int32_t LoadInt32 (int32_t *addr)
-  __asm__ (GOSYM_PREFIX "sync..z2fatomic.LoadInt32")
+  __asm__ (GOSYM_PREFIX "sync_1atomic.LoadInt32")
   __attribute__ ((no_split_stack));
 
 int32_t
@@ -186,7 +186,7 @@ LoadInt32 (int32_t *addr)
 }
 
 int64_t LoadInt64 (int64_t *addr)
-  __asm__ (GOSYM_PREFIX "sync..z2fatomic.LoadInt64")
+  __asm__ (GOSYM_PREFIX "sync_1atomic.LoadInt64")
   __attribute__ ((no_split_stack));
 
 int64_t
@@ -198,7 +198,7 @@ LoadInt64 (int64_t *addr)
 }
 
 uint32_t LoadUint32 (uint32_t *addr)
-  __asm__ (GOSYM_PREFIX "sync..z2fatomic.LoadUint32")
+  __asm__ (GOSYM_PREFIX "sync_1atomic.LoadUint32")
   __attribute__ ((no_split_stack));
 
 uint32_t
@@ -208,7 +208,7 @@ LoadUint32 (uint32_t *addr)
 }
 
 uint64_t LoadUint64 (uint64_t *addr)
-  __asm__ (GOSYM_PREFIX "sync..z2fatomic.LoadUint64")
+  __asm__ (GOSYM_PREFIX "sync_1atomic.LoadUint64")
   __attribute__ ((no_split_stack));
 
 uint64_t
@@ -220,7 +220,7 @@ LoadUint64 (uint64_t *addr)
 }
 
 uintptr_t LoadUintptr (uintptr_t *addr)
-  __asm__ (GOSYM_PREFIX "sync..z2fatomic.LoadUintptr")
+  __asm__ (GOSYM_PREFIX "sync_1atomic.LoadUintptr")
   __attribute__ ((no_split_stack));
 
 uintptr_t
@@ -230,7 +230,7 @@ LoadUintptr (uintptr_t *addr)
 }
 
 void *LoadPointer (void **addr)
-  __asm__ (GOSYM_PREFIX "sync..z2fatomic.LoadPointer")
+  __asm__ (GOSYM_PREFIX "sync_1atomic.LoadPointer")
   __attribute__ ((no_split_stack));
 
 void *
@@ -240,7 +240,7 @@ LoadPointer (void **addr)
 }
 
 void StoreInt32 (int32_t *addr, int32_t val)
-  __asm__ (GOSYM_PREFIX "sync..z2fatomic.StoreInt32")
+  __asm__ (GOSYM_PREFIX "sync_1atomic.StoreInt32")
   __attribute__ ((no_split_stack));
 
 void
@@ -250,7 +250,7 @@ StoreInt32 (int32_t *addr, int32_t val)
 }
 
 void StoreInt64 (int64_t *addr, int64_t val)
-  __asm__ (GOSYM_PREFIX "sync..z2fatomic.StoreInt64")
+  __asm__ (GOSYM_PREFIX "sync_1atomic.StoreInt64")
   __attribute__ ((no_split_stack));
 
 void
@@ -262,7 +262,7 @@ StoreInt64 (int64_t *addr, int64_t val)
 }
 
 void StoreUint32 (uint32_t *addr, uint32_t val)
-  __asm__ (GOSYM_PREFIX "sync..z2fatomic.StoreUint32")
+  __asm__ (GOSYM_PREFIX "sync_1atomic.StoreUint32")
   __attribute__ ((no_split_stack));
 
 void
@@ -272,7 +272,7 @@ StoreUint32 (uint32_t *addr, uint32_t val)
 }
 
 void StoreUint64 (uint64_t *addr, uint64_t val)
-  __asm__ (GOSYM_PREFIX "sync..z2fatomic.StoreUint64")
+  __asm__ (GOSYM_PREFIX "sync_1atomic.StoreUint64")
   __attribute__ ((no_split_stack));
 
 void
@@ -284,7 +284,7 @@ StoreUint64 (uint64_t *addr, uint64_t val)
 }
 
 void StoreUintptr (uintptr_t *addr, uintptr_t val)
-  __asm__ (GOSYM_PREFIX "sync..z2fatomic.StoreUintptr")
+  __asm__ (GOSYM_PREFIX "sync_1atomic.StoreUintptr")
   __attribute__ ((no_split_stack));
 
 void
diff --git a/libgo/runtime/go-ffi.c b/libgo/runtime/go-ffi.c
index b030f5e..1ec5f87 100644
--- a/libgo/runtime/go-ffi.c
+++ b/libgo/runtime/go-ffi.c
@@ -16,36 +16,36 @@
    the libffi type values.  */
 
 ffi_type *go_ffi_type_pointer(void) __attribute__ ((no_split_stack));
-ffi_type *go_ffi_type_pointer(void) __asm__ ("runtime.ffi_type_pointer");
+ffi_type *go_ffi_type_pointer(void) __asm__ ("runtime.ffi__type__pointer");
 ffi_type *go_ffi_type_sint8(void) __attribute__ ((no_split_stack));
-ffi_type *go_ffi_type_sint8(void) __asm__ ("runtime.ffi_type_sint8");
+ffi_type *go_ffi_type_sint8(void) __asm__ ("runtime.ffi__type__sint8");
 ffi_type *go_ffi_type_sint16(void) __attribute__ ((no_split_stack));
-ffi_type *go_ffi_type_sint16(void) __asm__ ("runtime.ffi_type_sint16");
+ffi_type *go_ffi_type_sint16(void) __asm__ ("runtime.ffi__type__sint16");
 ffi_type *go_ffi_type_sint32(void) __attribute__ ((no_split_stack));
-ffi_type *go_ffi_type_sint32(void) __asm__ ("runtime.ffi_type_sint32");
+ffi_type *go_ffi_type_sint32(void) __asm__ ("runtime.ffi__type__sint32");
 ffi_type *go_ffi_type_sint64(void) __attribute__ ((no_split_stack));
-ffi_type *go_ffi_type_sint64(void) __asm__ ("runtime.ffi_type_sint64");
+ffi_type *go_ffi_type_sint64(void) __asm__ ("runtime.ffi__type__sint64");
 ffi_type *go_ffi_type_uint8(void) __attribute__ ((no_split_stack));
-ffi_type *go_ffi_type_uint8(void) __asm__ ("runtime.ffi_type_uint8");
+ffi_type *go_ffi_type_uint8(void) __asm__ ("runtime.ffi__type__uint8");
 ffi_type *go_ffi_type_uint16(void) __attribute__ ((no_split_stack));
-ffi_type *go_ffi_type_uint16(void) __asm__ ("runtime.ffi_type_uint16");
+ffi_type *go_ffi_type_uint16(void) __asm__ ("runtime.ffi__type__uint16");
 ffi_type *go_ffi_type_uint32(void) __attribute__ ((no_split_stack));
-ffi_type *go_ffi_type_uint32(void) __asm__ ("runtime.ffi_type_uint32");
+ffi_type *go_ffi_type_uint32(void) __asm__ ("runtime.ffi__type__uint32");
 ffi_type *go_ffi_type_uint64(void) __attribute__ ((no_split_stack));
-ffi_type *go_ffi_type_uint64(void) __asm__ ("runtime.ffi_type_uint64");
+ffi_type *go_ffi_type_uint64(void) __asm__ ("runtime.ffi__type__uint64");
 ffi_type *go_ffi_type_float(void) __attribute__ ((no_split_stack));
-ffi_type *go_ffi_type_float(void) __asm__ ("runtime.ffi_type_float");
+ffi_type *go_ffi_type_float(void) __asm__ ("runtime.ffi__type__float");
 ffi_type *go_ffi_type_double(void) __attribute__ ((no_split_stack));
-ffi_type *go_ffi_type_double(void) __asm__ ("runtime.ffi_type_double");
+ffi_type *go_ffi_type_double(void) __asm__ ("runtime.ffi__type__double");
 ffi_type *go_ffi_type_complex_float(void) __attribute__ ((no_split_stack));
-ffi_type *go_ffi_type_complex_float(void) __asm__ ("runtime.ffi_type_complex_float");
+ffi_type *go_ffi_type_complex_float(void) __asm__ ("runtime.ffi__type__complex__float");
 ffi_type *go_ffi_type_complex_double(void) __attribute__ ((no_split_stack));
-ffi_type *go_ffi_type_complex_double(void) __asm__ ("runtime.ffi_type_complex_double");
+ffi_type *go_ffi_type_complex_double(void) __asm__ ("runtime.ffi__type__complex__double");
 ffi_type *go_ffi_type_void(void) __attribute__ ((no_split_stack));
-ffi_type *go_ffi_type_void(void) __asm__ ("runtime.ffi_type_void");
+ffi_type *go_ffi_type_void(void) __asm__ ("runtime.ffi__type__void");
 
 _Bool go_ffi_supports_complex(void) __attribute__ ((no_split_stack));
-_Bool go_ffi_supports_complex(void) __asm__ ("runtime.ffi_supports_complex");
+_Bool go_ffi_supports_complex(void) __asm__ ("runtime.ffi__supports__complex");
 
 ffi_type *
 go_ffi_type_pointer(void)
diff --git a/libgo/runtime/go-setenv.c b/libgo/runtime/go-setenv.c
index 81b1775..08987de 100644
--- a/libgo/runtime/go-setenv.c
+++ b/libgo/runtime/go-setenv.c
@@ -13,7 +13,7 @@
 
 /* Set the C environment from Go.  This is called by syscall.Setenv.  */
 
-void setenv_c (String, String) __asm__ (GOSYM_PREFIX "syscall.setenv_c");
+void setenv_c (String, String) __asm__ (GOSYM_PREFIX "syscall.setenv__c");
 
 void
 setenv_c (String k, String v)
diff --git a/libgo/runtime/go-unsafe-pointer.c b/libgo/runtime/go-unsafe-pointer.c
index 364878e..e24bfb2 100644
--- a/libgo/runtime/go-unsafe-pointer.c
+++ b/libgo/runtime/go-unsafe-pointer.c
@@ -72,7 +72,7 @@ const struct _type unsafe_Pointer =
    it to be defined elsewhere.  */
 
 extern const struct ptrtype pointer_unsafe_Pointer
-  __asm__ (GOSYM_PREFIX "type...1unsafe.Pointer");
+  __asm__ (GOSYM_PREFIX "unsafe.Pointer..p");
 
 /* The reflection string.  */
 #define PREFLECTION "*unsafe.Pointer"
@@ -83,7 +83,7 @@ static const String preflection_string =
 };
 
 extern const byte pointer_unsafe_Pointer_gc[]
-  __asm__ (GOSYM_PREFIX "type...1unsafe.Pointer..g");
+  __asm__ (GOSYM_PREFIX "unsafe.Pointer..p..g");
 
 const byte pointer_unsafe_Pointer_gc[] = { 1 };
 
diff --git a/libgo/runtime/go-unsetenv.c b/libgo/runtime/go-unsetenv.c
index 2135997..4b5058a 100644
--- a/libgo/runtime/go-unsetenv.c
+++ b/libgo/runtime/go-unsetenv.c
@@ -14,7 +14,7 @@
 /* Unset an environment variable from Go.  This is called by
    syscall.Unsetenv.  */
 
-void unsetenv_c (String) __asm__ (GOSYM_PREFIX "syscall.unsetenv_c");
+void unsetenv_c (String) __asm__ (GOSYM_PREFIX "syscall.unsetenv__c");
 
 void
 unsetenv_c (String k)
diff --git a/libgo/runtime/runtime.h b/libgo/runtime/runtime.h
index f46eaea..3a65d44 100644
--- a/libgo/runtime/runtime.h
+++ b/libgo/runtime/runtime.h
@@ -440,7 +440,7 @@ void	runtime_freedefer(Defer*);
 
 extern void _cgo_wait_runtime_init_done (void);
 extern void _cgo_notify_runtime_init_done (void)
-  __asm__ (GOSYM_PREFIX "runtime._cgo_notify_runtime_init_done");
+  __asm__ (GOSYM_PREFIX "runtime.__cgo__notify__runtime__init__done");
 extern _Bool runtime_iscgo;
 extern uintptr __go_end __attribute__ ((weak));
 extern void *getitab(const struct _type *, const struct _type *, _Bool)
diff --git a/libgo/testsuite/gotest b/libgo/testsuite/gotest
index 0fd6419..8c3c5ca 100755
--- a/libgo/testsuite/gotest
+++ b/libgo/testsuite/gotest
@@ -496,7 +496,8 @@ testname() {
 localname() {
 	# The package main has been renamed to __main__ when imported.
 	# Adjust its uses.
-	echo $1 | sed 's/^main\./__main__./'
+	# Also demangle underscores.
+	echo $1 | sed 's/^main\./__main__./' | sed 's/__/_/'
 }
 
 # Takes a list of tests derived from 'nm' output (whose symbols are mangled)
@@ -504,7 +505,7 @@ localname() {
 # Example:
 #
 #    Original symbol:   foo/bar/leaf.Mumble
-#    Mangled symbol:    foo..z2fbar..z2fleaf.Mumble
+#    Mangled symbol:    foo_1fbar_1leaf.Mumble
 #    Returned:          leaf.Mumble
 #
 symtogo() {
@@ -522,7 +523,7 @@ symtogo() {
     if expr "$tp" : '^type\.\.' >/dev/null 2>&1; then
       continue
     fi
-    s=$(echo "$tp" | sed -e 's/\.\.z2f/%/g' | sed -e 's/.*%//')
+    s=$(echo "$tp" | sed -e 's/_1/%/g' | sed -e 's/.*%//')
     # Screen out methods (X.Y.Z).
     if ! expr "$s" : '^[^.]*\.[^.]*$' >/dev/null 2>&1; then
       continue