debug/plan9obj: implement parsing of Plan 9 a.out executables

It implements parsing of the header and symbol table for both
32-bit and 64-bit Plan 9 binaries. The nm tool was updated to
use this package.

R=rsc, aram
CC=golang-codereviews
https://golang.org/cl/49970044

1 files changed, 81 insertions, 0 deletions

diff --git a/src/pkg/debug/plan9obj/file_test.go b/src/pkg/debug/plan9obj/file_test.go
new file mode 100644
index 0000000000..cc1db40929
--- /dev/null
+++ b/src/pkg/debug/plan9obj/file_test.go
@@ -0,0 +1,81 @@
+// 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 plan9obj
+
+import (
+	"reflect"
+	"testing"
+)
+
+type fileTest struct {
+	file     string
+	hdr      FileHeader
+	sections []*SectionHeader
+}
+
+var fileTests = []fileTest{
+	{
+		"testdata/386-plan9-exec",
+		FileHeader{4},
+		[]*SectionHeader{
+			{"text", 0x4c5f, 0x20},
+			{"data", 0x94c, 0x4c7f},
+			{"syms", 0x2c2b, 0x55cb},
+			{"spsz", 0x0, 0x81f6},
+			{"pcsz", 0xf7a, 0x81f6},
+		},
+	},
+	{
+		"testdata/amd64-plan9-exec",
+		FileHeader{8},
+		[]*SectionHeader{
+			{"text", 0x4213, 0x28},
+			{"data", 0xa80, 0x423b},
+			{"syms", 0x2c8c, 0x4cbb},
+			{"spsz", 0x0, 0x7947},
+			{"pcsz", 0xca0, 0x7947},
+		},
+	},
+}
+
+func TestOpen(t *testing.T) {
+	for i := range fileTests {
+		tt := &fileTests[i]
+
+		f, err := Open(tt.file)
+		if err != nil {
+			t.Error(err)
+			continue
+		}
+		if !reflect.DeepEqual(f.FileHeader, tt.hdr) {
+			t.Errorf("open %s:\n\thave %#v\n\twant %#v\n", tt.file, f.FileHeader, tt.hdr)
+			continue
+		}
+
+		for i, sh := range f.Sections {
+			if i >= len(tt.sections) {
+				break
+			}
+			have := &sh.SectionHeader
+			want := tt.sections[i]
+			if !reflect.DeepEqual(have, want) {
+				t.Errorf("open %s, section %d:\n\thave %#v\n\twant %#v\n", tt.file, i, have, want)
+			}
+		}
+		tn := len(tt.sections)
+		fn := len(f.Sections)
+		if tn != fn {
+			t.Errorf("open %s: len(Sections) = %d, want %d", tt.file, fn, tn)
+		}
+	}
+}
+
+func TestOpenFailure(t *testing.T) {
+	filename := "file.go"    // not a Plan 9 a.out file
+	_, err := Open(filename) // don't crash
+	if err == nil {
+		t.Errorf("open %s: succeeded unexpectedly", filename)
+	}
+}