cmd/addr2line: works with windows pe executables now

Update #7406
Fixes #7899

LGTM=bradfitz
R=golang-codereviews, rsc, bradfitz
CC=golang-codereviews
https://golang.org/cl/96960043

src/cmd/addr2line/addr2line_test.go

+// Copyright 2014 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"
+	"bytes"
+	"io/ioutil"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"runtime"
+	"strings"
+	"testing"
+)
+
+func loadSyms(t *testing.T) map[string]string {
+	cmd := exec.Command("go", "tool", "nm", os.Args[0])
+	out, err := cmd.CombinedOutput()
+	if err != nil {
+		t.Fatalf("go tool nm %v: %v\n%s", os.Args[0], err, string(out))
+	}
+	syms := make(map[string]string)
+	scanner := bufio.NewScanner(bytes.NewReader(out))
+	for scanner.Scan() {
+		f := strings.Fields(scanner.Text())
+		if len(f) < 3 {
+			continue
+		}
+		syms[f[2]] = f[0]
+	}
+	if err := scanner.Err(); err != nil {
+		t.Fatalf("error reading symbols: %v", err)
+	}
+	return syms
+}
+
+func runAddr2Line(t *testing.T, exepath, addr string) (funcname, path, lineno string) {
+	cmd := exec.Command(exepath, os.Args[0])
+	cmd.Stdin = strings.NewReader(addr)
+	out, err := cmd.CombinedOutput()
+	if err != nil {
+		t.Fatalf("go tool addr2line %v: %v\n%s", os.Args[0], err, string(out))
+	}
+	f := strings.Split(string(out), "\n")
+	if len(f) < 3 && f[2] == "" {
+		t.Fatal("addr2line output must have 2 lines")
+	}
+	funcname = f[0]
+	pathAndLineNo := f[1]
+	f = strings.Split(pathAndLineNo, ":")
+	if runtime.GOOS == "windows" {
+		switch len(f) {
+		case 2:
+			return funcname, f[0], f[1]
+		case 3:
+			return funcname, f[0] + ":" + f[1], f[2]
+		default:
+			t.Fatalf("no line number found in %q", pathAndLineNo)
+		}
+	}
+	if len(f) != 2 {
+		t.Fatalf("no line number found in %q", pathAndLineNo)
+	}
+	return funcname, f[0], f[1]
+}
+
+func TestAddr2Line(t *testing.T) {
+	syms := loadSyms(t)
+
+	tmpDir, err := ioutil.TempDir("", "TestAddr2Line")
+	if err != nil {
+		t.Fatal("TempDir failed: ", err)
+	}
+	defer os.RemoveAll(tmpDir)
+
+	exepath := filepath.Join(tmpDir, "testaddr2line.exe")
+	out, err := exec.Command("go", "build", "-o", exepath, "cmd/addr2line").CombinedOutput()
+	if err != nil {
+		t.Fatalf("go build -o %v cmd/addr2line: %v\n%s", exepath, err, string(out))
+	}
+
+	const symName = "cmd/addr2line.TestAddr2Line"
+	funcName, srcPath, srcLineNo := runAddr2Line(t, exepath, syms[symName])
+	if symName != funcName {
+		t.Fatalf("expected function name %v; got %v", symName, funcName)
+	}
+	fi1, err := os.Stat("addr2line_test.go")
+	if err != nil {
+		t.Fatalf("Stat failed: %v", err)
+	}
+	fi2, err := os.Stat(srcPath)
+	if err != nil {
+		t.Fatalf("Stat failed: %v", err)
+	}
+	if !os.SameFile(fi1, fi2) {
+		t.Fatalf("addr2line_test.go and %s are not same file", srcPath)
+	}
+	if srcLineNo != "70" {
+		t.Fatalf("line number = %v; want 70", srcLineNo)
+	}
+}

src/cmd/addr2line/main.go

@@ -141,18 +141,50 @@ func loadTables(f *os.File) (textStart uint64, symtab, pclntab []byte, err error
 		if sect := obj.Section(".text"); sect != nil {
 			textStart = uint64(sect.VirtualAddress)
 		}
-		if sect := obj.Section(".gosymtab"); sect != nil {
-			if symtab, err = sect.Data(); err != nil {
-				return 0, nil, nil, err
-			}
+		if pclntab, err = loadPETable(obj, "pclntab", "epclntab"); err != nil {
+			return 0, nil, nil, err
 		}
-		if sect := obj.Section(".gopclntab"); sect != nil {
-			if pclntab, err = sect.Data(); err != nil {
-				return 0, nil, nil, err
-			}
+		if symtab, err = loadPETable(obj, "symtab", "esymtab"); err != nil {
+			return 0, nil, nil, err
 		}
 		return textStart, symtab, pclntab, nil
 	}
 
 	return 0, nil, nil, fmt.Errorf("unrecognized binary format")
 }
+
+func findPESymbol(f *pe.File, name string) (*pe.Symbol, error) {
+	for _, s := range f.Symbols {
+		if s.Name != name {
+			continue
+		}
+		if s.SectionNumber <= 0 {
+			return nil, fmt.Errorf("symbol %s: invalid section number %d", name, s.SectionNumber)
+		}
+		if len(f.Sections) < int(s.SectionNumber) {
+			return nil, fmt.Errorf("symbol %s: section number %d is larger than max %d", name, s.SectionNumber, len(f.Sections))
+		}
+		return s, nil
+	}
+	return nil, fmt.Errorf("no %s symbol found", name)
+}
+
+func loadPETable(f *pe.File, sname, ename string) ([]byte, error) {
+	ssym, err := findPESymbol(f, sname)
+	if err != nil {
+		return nil, err
+	}
+	esym, err := findPESymbol(f, ename)
+	if err != nil {
+		return nil, err
+	}
+	if ssym.SectionNumber != esym.SectionNumber {
+		return nil, fmt.Errorf("%s and %s symbols must be in the same section", sname, ename)
+	}
+	sect := f.Sections[ssym.SectionNumber-1]
+	data, err := sect.Data()
+	if err != nil {
+		return nil, err
+	}
+	return data[ssym.Value:esym.Value], nil
+}