cmd/pprof: don't use offset if we don't have a start address

The test is in the runtime package because there are other tests of
pprof there. At some point we should probably move them all into a pprof
testsuite.

Fixes #16128.

Change-Id: Ieefa40c61cf3edde11fe0cf04da1debfd8b3d7c0
Reviewed-on: https://go-review.googlesource.com/24274
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Andrew Gerrand <adg@golang.org>

1 files changed, 49 insertions, 0 deletions

diff --git a/src/runtime/testdata/testprog/memprof.go b/src/runtime/testdata/testprog/memprof.go
new file mode 100644
index 0000000000..a22fee61d7
--- /dev/null
+++ b/src/runtime/testdata/testprog/memprof.go
@@ -0,0 +1,49 @@
+// Copyright 2016 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 (
+	"bytes"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"runtime"
+	"runtime/pprof"
+)
+
+func init() {
+	register("MemProf", MemProf)
+}
+
+var memProfBuf bytes.Buffer
+var memProfStr string
+
+func MemProf() {
+	for i := 0; i < 1000; i++ {
+		fmt.Fprintf(&memProfBuf, "%*d\n", i, i)
+	}
+	memProfStr = memProfBuf.String()
+
+	runtime.GC()
+
+	f, err := ioutil.TempFile("", "memprof")
+	if err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(2)
+	}
+
+	if err := pprof.WriteHeapProfile(f); err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(2)
+	}
+
+	name := f.Name()
+	if err := f.Close(); err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(2)
+	}
+
+	fmt.Println(name)
+}