cmd/pprof: make ObjAddr a no-op

https://golang.org/cl/318049 replaced driver.ObjFile.Base with
driver.ObjFile.ObjAddr. We don't support shared libraries, so these
should be no-op, but CL 318049 accidentally failed to account from the
change in no-op behavior from returning 0 to passing through addr.

Fixes #46636

Change-Id: Iab82224c7db722a1e257ec6e305218e22114d0a8
Reviewed-on: https://go-review.googlesource.com/c/go/+/325809
Trust: Michael Pratt <mpratt@google.com>
Run-TryBot: Michael Pratt <mpratt@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cherry Mui <cherryyz@google.com>

src/cmd/pprof/pprof.go

@@ -233,8 +233,8 @@ func (f *file) Name() string {
 }
 
 func (f *file) ObjAddr(addr uint64) (uint64, error) {
-	// No support for shared libraries.
-	return 0, nil
+	// No support for shared libraries, so translation is a no-op.
+	return addr, nil
 }
 
 func (f *file) BuildID() string {

src/cmd/pprof/pprof_test.go

@@ -0,0 +1,110 @@
+// Copyright 2021 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 (
+	"fmt"
+	"internal/testenv"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"runtime"
+	"strings"
+	"testing"
+)
+
+var tmp, pprofExe string // populated by buildPprof
+
+func TestMain(m *testing.M) {
+	if !testenv.HasGoBuild() {
+		return
+	}
+
+	var exitcode int
+	if err := buildPprof(); err == nil {
+		exitcode = m.Run()
+	} else {
+		fmt.Println(err)
+		exitcode = 1
+	}
+	os.RemoveAll(tmp)
+	os.Exit(exitcode)
+}
+
+func buildPprof() error {
+	var err error
+	tmp, err = os.MkdirTemp("", "TestPprof")
+	if err != nil {
+		return fmt.Errorf("TempDir failed: %v", err)
+	}
+
+	pprofExe = filepath.Join(tmp, "testpprof.exe")
+	gotool, err := testenv.GoTool()
+	if err != nil {
+		return err
+	}
+	out, err := exec.Command(gotool, "build", "-o", pprofExe, "cmd/pprof").CombinedOutput()
+	if err != nil {
+		os.RemoveAll(tmp)
+		return fmt.Errorf("go build -o %v cmd/pprof: %v\n%s", pprofExe, err, string(out))
+	}
+
+	return nil
+}
+
+func mustHaveDisasm(t *testing.T) {
+	switch runtime.GOARCH {
+	case "mips", "mipsle", "mips64", "mips64le":
+		t.Skipf("skipping on %s, issue 12559", runtime.GOARCH)
+	case "riscv64":
+		t.Skipf("skipping on %s, issue 36738", runtime.GOARCH)
+	case "s390x":
+		t.Skipf("skipping on %s, issue 15255", runtime.GOARCH)
+	}
+
+	// Skip PIE platforms, pprof can't disassemble PIE.
+	if runtime.GOOS == "windows" {
+		t.Skipf("skipping on %s, issue 46639", runtime.GOOS)
+	}
+	if runtime.GOOS == "darwin" && runtime.GOARCH == "arm64" {
+		t.Skipf("skipping on %s/%s, issue 46639", runtime.GOOS, runtime.GOARCH)
+	}
+}
+
+// TestDisasm verifies that cmd/pprof can successfully disassemble functions.
+//
+// This is a regression test for issue 46636.
+func TestDisasm(t *testing.T) {
+	mustHaveDisasm(t)
+	testenv.MustHaveGoBuild(t)
+
+	tmpdir := t.TempDir()
+	cpuExe := filepath.Join(tmpdir, "cpu.exe")
+	cmd := exec.Command(testenv.GoToolPath(t), "build", "-o", cpuExe, "cpu.go")
+	cmd.Dir = "testdata/"
+	out, err := cmd.CombinedOutput()
+	if err != nil {
+		t.Fatalf("build failed: %v\n%s", err, out)
+	}
+
+	profile := filepath.Join(tmpdir, "cpu.pprof")
+	cmd = exec.Command(cpuExe, "-output", profile)
+	out, err = cmd.CombinedOutput()
+	if err != nil {
+		t.Fatalf("cpu failed: %v\n%s", err, out)
+	}
+
+	cmd = exec.Command(pprofExe, "-disasm", "main.main", cpuExe, profile)
+	out, err = cmd.CombinedOutput()
+	if err != nil {
+		t.Fatalf("pprof failed: %v\n%s", err, out)
+	}
+
+	sout := string(out)
+	want := "ROUTINE ======================== main.main"
+	if !strings.Contains(sout, want) {
+		t.Errorf("pprof disasm got %s want contains %q", sout, want)
+	}
+}

src/cmd/pprof/testdata/cpu.go

@@ -0,0 +1,41 @@
+// Copyright 2021 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 (
+	"flag"
+	"fmt"
+	"os"
+	"runtime/pprof"
+	"time"
+)
+
+var output = flag.String("output", "", "pprof profile output file")
+
+func main() {
+	flag.Parse()
+	if *output == "" {
+		fmt.Fprintf(os.Stderr, "usage: %s -output file.pprof\n", os.Args[0])
+		os.Exit(2)
+	}
+
+	f, err := os.Create(*output)
+	if err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(2)
+	}
+	defer f.Close()
+
+	if err := pprof.StartCPUProfile(f); err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(2)
+	}
+	defer pprof.StopCPUProfile()
+
+	// Spin for long enough to collect some samples.
+	start := time.Now()
+	for time.Since(start) < time.Second {
+	}
+}