[gdb/testsuite] Move gpu-parallel.lock to cache dir

The lock directory returned by lock_dir is currently $objdir.

It seems possible to leave a stale lock file that blocks progress in a
following run.

Fix this by using a directory that is guaranteed to be initially empty when
using GDB_PARALLEL, like temp or cache.

In gdb/testsuite/README I found:
...
cache in particular is used to share data across invocations of runtest
...
which seems appropriate, so let's use cache for this.

Tested on aarch64-linux.

Approved-By: Tom Tromey <tom@tromey.com>

diff --git a/gdb/testsuite/lib/gdb-utils.exp b/gdb/testsuite/lib/gdb-utils.exp
index c0b96d3c2bf06a3e3549e5c023215384e603e1f6..1f30d807ff052a1987c26206d7b340320e815da4 100644 (file)
--- a/gdb/testsuite/lib/gdb-utils.exp
+++ b/gdb/testsuite/lib/gdb-utils.exp
@@ -180,7 +180,7 @@ proc lock_file_release {info} {
 # Return directory where we keep lock files.
 
 proc lock_dir {} {
-    return $objdir
+    return [make_gdb_parallel_path cache]
 }
 
 # Run body under lock LOCK_FILE.