1 files changed, 167 insertions, 0 deletions
diff --git a/src/cmd/nm/nm.go b/src/cmd/nm/nm.go
new file mode 100644
index 0000000..78fa600
--- /dev/null
+++ b/src/cmd/nm/nm.go
@@ -0,0 +1,167 @@
+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+import (
+	"bufio"
+	"flag"
+	"fmt"
+	"log"
+	"os"
+	"sort"
+
+	"cmd/internal/objfile"
+)
+
+const helpText = `usage: go tool nm [options] file...
+  -n
+      an alias for -sort address (numeric),
+      for compatibility with other nm commands
+  -size
+      print symbol size in decimal between address and type
+  -sort {address,name,none,size}
+      sort output in the given order (default name)
+      size orders from largest to smallest
+  -type
+      print symbol type after name
+`
+
+func usage() {
+	fmt.Fprint(os.Stderr, helpText)
+	os.Exit(2)
+}
+
+var (
+	sortOrder = flag.String("sort", "name", "")
+	printSize = flag.Bool("size", false, "")
+	printType = flag.Bool("type", false, "")
+
+	filePrefix = false
+)
+
+func init() {
+	flag.Var(nflag(0), "n", "") // alias for -sort address
+}
+
+type nflag int
+
+func (nflag) IsBoolFlag() bool {
+	return true
+}
+
+func (nflag) Set(value string) error {
+	if value == "true" {
+		*sortOrder = "address"
+	}
+	return nil
+}
+
+func (nflag) String() string {
+	if *sortOrder == "address" {
+		return "true"
+	}
+	return "false"
+}
+
+func main() {
+	log.SetFlags(0)
+	flag.Usage = usage
+	flag.Parse()
+
+	switch *sortOrder {
+	case "address", "name", "none", "size":
+		// ok
+	default:
+		fmt.Fprintf(os.Stderr, "nm: unknown sort order %q\n", *sortOrder)
+		os.Exit(2)
+	}
+
+	args := flag.Args()
+	filePrefix = len(args) > 1
+	if len(args) == 0 {
+		flag.Usage()
+	}
+
+	for _, file := range args {
+		nm(file)
+	}
+
+	os.Exit(exitCode)
+}
+
+var exitCode = 0
+
+func errorf(format string, args ...any) {
+	log.Printf(format, args...)
+	exitCode = 1
+}
+
+func nm(file string) {
+	f, err := objfile.Open(file)
+	if err != nil {
+		errorf("%v", err)
+		return
+	}
+	defer f.Close()
+
+	w := bufio.NewWriter(os.Stdout)
+
+	entries := f.Entries()
+
+	var found bool
+
+	for _, e := range entries {
+		syms, err := e.Symbols()
+		if err != nil {
+			errorf("reading %s: %v", file, err)
+		}
+		if len(syms) == 0 {
+			continue
+		}
+
+		found = true
+
+		switch *sortOrder {
+		case "address":
+			sort.Slice(syms, func(i, j int) bool { return syms[i].Addr < syms[j].Addr })
+		case "name":
+			sort.Slice(syms, func(i, j int) bool { return syms[i].Name < syms[j].Name })
+		case "size":
+			sort.Slice(syms, func(i, j int) bool { return syms[i].Size > syms[j].Size })
+		}
+
+		for _, sym := range syms {
+			if len(entries) > 1 {
+				name := e.Name()
+				if name == "" {
+					fmt.Fprintf(w, "%s(%s):\t", file, "_go_.o")
+				} else {
+					fmt.Fprintf(w, "%s(%s):\t", file, name)
+				}
+			} else if filePrefix {
+				fmt.Fprintf(w, "%s:\t", file)
+			}
+			if sym.Code == 'U' {
+				fmt.Fprintf(w, "%8s", "")
+			} else {
+				fmt.Fprintf(w, "%8x", sym.Addr)
+			}
+			if *printSize {
+				fmt.Fprintf(w, " %10d", sym.Size)
+			}
+			fmt.Fprintf(w, " %c %s", sym.Code, sym.Name)
+			if *printType && sym.Type != "" {
+				fmt.Fprintf(w, " %s", sym.Type)
+			}
+			fmt.Fprintf(w, "\n")
+		}
+	}
+
+	if !found {
+		errorf("reading %s: no symbols", file)
+	}
+
+	w.Flush()
+}