[PATCH] testsuite: diagnose a running GDB in gdb_skip_xml_tests

[Markus Metzger <markus.t.metzger@intel.com>]

If GDB is running when gdb_skip_xml_tests is called with
--target_board=native-extended-gdbserer.exp, it fails with:

    (gdb) FAIL: ....exp: set tdesc filename .../trivial.xml (got interactive prompt)
    monitor exit

Diagnose this in gdb_skip_xml_tests to generate a more meaningful error message:

    ERROR: tcl error sourcing ....exp.
    ERROR: GDB must not be running in gdb_skip_xml_tests.
        while executing
    [...]

2017-02-01  Markus Metzger  <markus.t.metzger@intel.com>

testsuite/
	* lib/gdb.exp (gdb_skip_xml_tests): Error if GDB is running.
---
 gdb/testsuite/lib/gdb.exp | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/gdb/testsuite/lib/gdb.exp b/gdb/testsuite/lib/gdb.exp
index 48bd7ee..188484f 100644
--- a/gdb/testsuite/lib/gdb.exp
+++ b/gdb/testsuite/lib/gdb.exp
@@ -5030,9 +5030,14 @@ proc gdb_skip_bogus_test { msg } {
 # NOTE: This must be called while gdb is *not* running.
 
 gdb_caching_proc gdb_skip_xml_test {
+    global gdb_spawn_id
     global gdb_prompt
     global srcdir
 
+    if { [info exists gdb_spawn_id] } {
+        error "GDB must not be running in gdb_skip_xml_tests."
+    }
+
     set xml_file [gdb_remote_download host "${srcdir}/gdb.xml/trivial.xml"]
 
     gdb_start
-- 
1.8.3.1