[committed][gdb/testsuite] Disable vgdb tests if xml not supported

[Tom de Vries <tdevries@suse.de>]

Hi,

I build gdb without xml support using --without-expat, and ran into:
...
(gdb) target remote | vgdb --wait=2 --max-invoke-ms=2500 --pid=22032^M
Remote debugging using | vgdb --wait=2 --max-invoke-ms=2500 --pid=22032^M
relaying data between gdb and process 22032^M
warning: Can not parse XML target description; XML support was disabled at \
  compile time^M
  ...
(gdb) PASS: gdb.base/valgrind-infcall.exp: continue #1
p gdb_test_infcall ()^M
Remote 'g' packet reply is too long (expected 560 bytes, got 800 bytes): ...^M
(gdb) FAIL: gdb.base/valgrind-infcall.exp: p gdb_test_infcall ()
...

After googling the error message with context valgrind gdbserver, I found
indications that the Remote 'g' packet reply error is due to missing xml
support.

And here ( https://www.valgrind.org/docs/manual/manual-core-adv.html ) I
found:
...
GDB version needed for ARM and PPC32/64.

You must use a GDB version which is able to read XML target description sent
by a gdbserver.  This is the standard setup if GDB was configured and built
with the "expat" library.  If your GDB was not configured with XML support, it
will report an error message when using the "target" command.  Debugging will
not work because GDB will then not be able to fetch the registers from the
Valgrind gdbserver.
...

So I guess I'm running into the same problem for x86_64.

Fix this by skipping all gdb.base/valgrind-*.exp tests if xml support is not
available.  Although only the gdb.base/valgrind-infcall*.exp produce fails,
the Remote 'g' packet reply error occurs in all tests, so it seems prudent to
disable them all.

Tested on x86_64-linux.

Committed to trunk.

Thanks,
- Tom

[gdb/testsuite] Disable vgdb tests if xml not supported

---
 gdb/testsuite/gdb.base/valgrind-bt.exp        | 5 +++++
 gdb/testsuite/gdb.base/valgrind-disp-step.exp | 5 +++++
 gdb/testsuite/gdb.base/valgrind-infcall-2.exp | 5 +++++
 gdb/testsuite/gdb.base/valgrind-infcall.exp   | 5 +++++
 4 files changed, 20 insertions(+)

diff --git a/gdb/testsuite/gdb.base/valgrind-bt.exp b/gdb/testsuite/gdb.base/valgrind-bt.exp
index b559e433d72..4b84a45d333 100644
--- a/gdb/testsuite/gdb.base/valgrind-bt.exp
+++ b/gdb/testsuite/gdb.base/valgrind-bt.exp
@@ -13,6 +13,11 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
+if { [gdb_skip_xml_test] } {
+    # Valgrind gdbserver requires gdb with xml support.
+    return 0
+}
+
 load_lib valgrind.exp
 
 if [is_remote target] {
diff --git a/gdb/testsuite/gdb.base/valgrind-disp-step.exp b/gdb/testsuite/gdb.base/valgrind-disp-step.exp
index 3aecf00a291..f9429fbd69a 100644
--- a/gdb/testsuite/gdb.base/valgrind-disp-step.exp
+++ b/gdb/testsuite/gdb.base/valgrind-disp-step.exp
@@ -18,6 +18,11 @@
 # really tests is that GDB falls back to in-line stepping
 # automatically instead of getting stuck or crashing.
 
+if { [gdb_skip_xml_test] } {
+    # Valgrind gdbserver requires gdb with xml support.
+    return 0
+}
+
 load_lib valgrind.exp
 
 if [is_remote target] {
diff --git a/gdb/testsuite/gdb.base/valgrind-infcall-2.exp b/gdb/testsuite/gdb.base/valgrind-infcall-2.exp
index 82b3f4e5c49..30881ca72ea 100644
--- a/gdb/testsuite/gdb.base/valgrind-infcall-2.exp
+++ b/gdb/testsuite/gdb.base/valgrind-infcall-2.exp
@@ -29,6 +29,11 @@
 # terminate called after throwing an instance of 'gdb_exception_error'
 # Aborted (core dumped)
 
+if { [gdb_skip_xml_test] } {
+    # Valgrind gdbserver requires gdb with xml support.
+    return 0
+}
+
 load_lib valgrind.exp
 
 if [is_remote target] {
diff --git a/gdb/testsuite/gdb.base/valgrind-infcall.exp b/gdb/testsuite/gdb.base/valgrind-infcall.exp
index 658d2bdb3de..0108f92ceaf 100644
--- a/gdb/testsuite/gdb.base/valgrind-infcall.exp
+++ b/gdb/testsuite/gdb.base/valgrind-infcall.exp
@@ -13,6 +13,11 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
+if { [gdb_skip_xml_test] } {
+    # Valgrind gdbserver requires gdb with xml support.
+    return 0
+}
+
 load_lib valgrind.exp
 
 if [is_remote target] {