runtime: fill basic FuncForPC metadata

runtime/internal/lib/runtime/pprof_runtime_stub_llgo.go

@@ -52,7 +52,3 @@ func NumGoroutine() int {
 }
 
 func SetCPUProfileRate(hz int) {}
-
-func FuncForPC(pc uintptr) *Func {
-	return nil
-}

runtime/internal/lib/runtime/symtab.go

@@ -105,6 +105,39 @@ func unknownFunctionName(pc uintptr) string {
 	return "pc=" + uintptrHex(pc)
 }
 
+func normalizeFunctionName(name string) string {
+	const stubPrefix = "__llgo_stub."
+	if len(name) > len(stubPrefix) && name[:len(stubPrefix)] == stubPrefix {
+		name = name[len(stubPrefix):]
+	}
+	switch name {
+	case "":
+		return ""
+	case "main":
+		return "main.main"
+	}
+	const mainPkg = "command-line-arguments."
+	if len(name) > len(mainPkg) && name[:len(mainPkg)] == mainPkg {
+		return "main." + name[len(mainPkg):]
+	}
+	return name
+}
+
+func pcInfo(pc uintptr) (name string, entry uintptr, ok bool) {
+	info := &clitedebug.Info{}
+	if clitedebug.Addrinfo(unsafe.Pointer(pc), info) == 0 && pc > 0 {
+		info = &clitedebug.Info{}
+		if clitedebug.Addrinfo(unsafe.Pointer(pc-1), info) == 0 {
+			return "", 0, false
+		}
+	}
+	name = normalizeFunctionName(safeGoString(info.Sname, ""))
+	if name == "" {
+		return "", 0, false
+	}
+	return name, uintptr(info.Saddr), true
+}
+
 func (ci *Frames) Next() (frame Frame, more bool) {
 	for len(ci.frames) < 2 {
 		// Find the next frame.
@@ -119,8 +152,8 @@ func (ci *Frames) Next() (frame Frame, more bool) {
 		} else {
 			pc, ci.callers = ci.callers[0], ci.callers[1:]
 		}
-		info := &clitedebug.Info{}
-		if clitedebug.Addrinfo(unsafe.Pointer(pc), info) == 0 {
+		fn := FuncForPC(pc)
+		if fn == nil {
 			ci.frames = append(ci.frames, Frame{
 				PC:        pc,
 				Function:  unknownFunctionName(pc),
@@ -131,17 +164,14 @@ func (ci *Frames) Next() (frame Frame, more bool) {
 			})
 			continue
 		}
-		fn := safeGoString(info.Sname, "")
-		if fn == "" {
-			fn = unknownFunctionName(pc)
-		}
 		ci.frames = append(ci.frames, Frame{
 			PC:        pc,
-			Function:  fn,
+			Func:      fn,
+			Function:  fn.Name(),
 			File:      "",
 			Line:      0,
 			startLine: 0,
-			Entry:     uintptr(info.Saddr),
+			Entry:     fn.Entry(),
 		})
 	}
 
@@ -176,11 +206,37 @@ func CallersFrames(callers []uintptr) *Frames {
 
 // A Func represents a Go function in the running binary.
 type Func struct {
-	opaque struct{} // unexported field to disallow conversions
+	entry uintptr
+	name  string
 }
 
 func (f *Func) Name() string {
-	panic("todo")
+	if f == nil {
+		return ""
+	}
+	return f.name
+}
+
+func (f *Func) Entry() uintptr {
+	if f == nil {
+		return 0
+	}
+	return f.entry
+}
+
+func (f *Func) FileLine(pc uintptr) (file string, line int) {
+	return "", 0
+}
+
+func FuncForPC(pc uintptr) *Func {
+	if pc == 0 {
+		return nil
+	}
+	name, entry, ok := pcInfo(pc)
+	if !ok {
+		return &Func{entry: pc, name: unknownFunctionName(pc)}
+	}
+	return &Func{entry: entry, name: name}
 }
 
 // moduledata records information about the layout of the executable

test/go/runtime_func_metadata_test.go

@@ -0,0 +1,76 @@
+/*
+ * Copyright (c) 2026 The XGo Authors (xgo.dev). All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package gotest
+
+import (
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+)
+
+const runtimeFuncMetadataProbe = `package main
+
+import (
+	"fmt"
+	"reflect"
+	"runtime"
+)
+
+type T struct {
+	a, b int
+}
+
+func f(t *T) int {
+	if t != nil {
+		return t.b
+	}
+	return 0
+}
+
+func g(t *T) int {
+	return f(t) + 5
+}
+
+func check(label, got, want string) {
+	if got != want {
+		panic(label + ": got " + got + ", want " + want)
+	}
+}
+
+func main() {
+	check("func f", runtime.FuncForPC(reflect.ValueOf(f).Pointer()).Name(), "main.f")
+	check("func g", runtime.FuncForPC(reflect.ValueOf(g).Pointer()).Name(), "main.g")
+	fmt.Println("ok")
+}
+`
+
+func TestRuntimeFuncMetadataWithLLGo(t *testing.T) {
+	dir := t.TempDir()
+	file := filepath.Join(dir, "main.go")
+	if err := os.WriteFile(file, []byte(runtimeFuncMetadataProbe), 0644); err != nil {
+		t.Fatal(err)
+	}
+
+	runGoCmd(t, dir, "run", file)
+
+	root := findLLGoRoot(t)
+	t.Setenv("LLGO_ROOT", root)
+	if got := strings.TrimSpace(runGoCmd(t, root, "run", "./cmd/llgo", "run", file)); got != "ok" {
+		t.Fatalf("llgo probe output = %q, want ok", got)
+	}
+}

test/goroot/xfail.yaml

@@ -2415,18 +2415,10 @@ xfails:
     directive: run
     case: fixedbugs/issue15281.go
     reason: latest main goroot run failure on darwin/arm64
-  - platform: darwin/arm64
-    directive: run
-    case: fixedbugs/issue17381.go
-    reason: latest main goroot run failure on darwin/arm64
   - platform: darwin/arm64
     directive: run
     case: fixedbugs/issue18149.go
     reason: latest main goroot run failure on darwin/arm64
-  - platform: darwin/arm64
-    directive: run
-    case: fixedbugs/issue21879.go
-    reason: latest main goroot run failure on darwin/arm64
   - platform: darwin/arm64
     directive: run
     case: fixedbugs/issue22083.go
@@ -2463,10 +2455,6 @@ xfails:
     directive: run
     case: fixedbugs/issue29504.go
     reason: latest main goroot run failure on darwin/arm64
-  - platform: darwin/arm64
-    directive: run
-    case: fixedbugs/issue29735.go
-    reason: latest main goroot run failure on darwin/arm64
   - platform: darwin/arm64
     directive: run
     case: fixedbugs/issue30116.go
@@ -2531,10 +2519,6 @@ xfails:
     directive: run
     case: fixedbugs/issue58300.go
     reason: latest main goroot run failure on darwin/arm64
-  - platform: darwin/arm64
-    directive: run
-    case: fixedbugs/issue58300b.go
-    reason: latest main goroot run failure on darwin/arm64
   - platform: darwin/arm64
     directive: run
     case: fixedbugs/issue5856.go