test: new test for issue 30908

New test case designed to mimic the code in issue 30908, which
features duplicate but non-indentical DWARF abstract subprogram DIEs.

Updates #30908.

Change-Id: Iacb4b53e6a988e46c801cdac236cef883c553f8f
Reviewed-on: https://go-review.googlesource.com/c/go/+/168957
Run-TryBot: Than McIntosh <thanm@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: David Chase <drchase@google.com>

test/fixedbugs/issue30908.dir/a.go

+// Copyright 2019 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 a
+
+import (
+	"errors"
+	"strings"
+)
+
+var G interface{}
+
+func Unmarshal(data []byte, o interface{}) error {
+	G = o
+	v, ok := o.(*map[string]interface{})
+	if !ok {
+		return errors.New("eek")
+	}
+	vals := make(map[string]interface{})
+	s := string(data)
+	items := strings.Split(s, " ")
+	var err error
+	for _, item := range items {
+		vals[item] = s
+		if item == "error" {
+			err = errors.New("ouch")
+		}
+	}
+	*v = vals
+	return err
+}

test/fixedbugs/issue30908.dir/b.go

+// Copyright 2019 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 b
+
+import (
+	"io/ioutil"
+
+	"./a"
+)
+
+var G int
+
+// An inlinable function. To trigger the bug in question this needs
+// to be inlined here within the package and also inlined into some
+// other package that imports it.
+func ReadValues(data []byte) (vals map[string]interface{}, err error) {
+	err = a.Unmarshal(data, &vals)
+	if len(vals) == 0 {
+		vals = map[string]interface{}{}
+	}
+	return
+}
+
+// A local call to the function above, which triggers the "move to heap"
+// of the output param.
+func CallReadValues(filename string) (map[string]interface{}, error) {
+	defer func() { G++ }()
+	data, err := ioutil.ReadFile(filename)
+	if err != nil {
+		return map[string]interface{}{}, err
+	}
+	return ReadValues(data)
+}

test/fixedbugs/issue30908.dir/m.go

+// Copyright 2019 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 (
+	"os"
+
+	"./b"
+)
+
+func main() {
+	seed := "some things are better"
+	bsl := []byte(seed)
+	b.CallReadValues("/dev/null")
+	vals, err := b.ReadValues(bsl)
+	if vals["better"] != seed || err != nil {
+		os.Exit(1)
+	}
+}

test/fixedbugs/issue30908.go

+// rundir -P -l=4 -ldflags -strictdups=2
+
+// Copyright 2019 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.
+
+// +build !nacl,!js
+
+package ignored