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

3 files changed, 8 insertions, 0 deletions

diff --git a/src/pkg/debug/plan9obj/testdata/386-plan9-exec b/src/pkg/debug/plan9obj/testdata/386-plan9-exec
new file mode 100755
index 0000000000..748e83f8e6
--- /dev/null
+++ b/src/pkg/debug/plan9obj/testdata/386-plan9-exec
diff --git a/src/pkg/debug/plan9obj/testdata/amd64-plan9-exec b/src/pkg/debug/plan9obj/testdata/amd64-plan9-exec
new file mode 100755
index 0000000000..3e257dd8ff
--- /dev/null
+++ b/src/pkg/debug/plan9obj/testdata/amd64-plan9-exec
diff --git a/src/pkg/debug/plan9obj/testdata/hello.c b/src/pkg/debug/plan9obj/testdata/hello.c
new file mode 100644
index 0000000000..c0d633e29f
--- /dev/null
+++ b/src/pkg/debug/plan9obj/testdata/hello.c
@@ -0,0 +1,8 @@
+#include <u.h>
+#include <libc.h>
+
+void
+main(void)
+{
+	print("hello, world\n");
+}