tests: parameterize --valgrind option

Running tests under helgrind and DRD recently proved useful in
tracking down thread interaction issues.  This can unfortunately not
be done through GIT_VALGRIND_OPTIONS because any tool other than
memcheck would complain about unknown options.

Let --valgrind take an optional parameter that describes the valgrind
tool to invoke.  The default mode is to run memcheck as before.

Signed-off-by: Thomas Rast <trast@inf.ethz.ch>
Acked-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 10 insertions, 5 deletions

diff --git a/t/README b/t/README
index bc7253c568..f5ee40f9c1 100644
--- a/t/README
+++ b/t/README
@@ -92,16 +92,21 @@ appropriately before running "make".
 	This causes additional long-running tests to be run (where
 	available), for more exhaustive testing.
 
---valgrind::
-	Execute all Git binaries with valgrind and exit with status
-	126 on errors (just like regular tests, this will only stop
-	the test script when running under -i).
+--valgrind=<tool>::
+	Execute all Git binaries under valgrind tool <tool> and exit
+	with status 126 on errors (just like regular tests, this will
+	only stop the test script when running under -i).
 
 	Since it makes no sense to run the tests with --valgrind and
 	not see any output, this option implies --verbose.  For
 	convenience, it also implies --tee.
 
-	Note that valgrind is run with the option --leak-check=no,
+	<tool> defaults to 'memcheck', just like valgrind itself.
+	Other particularly useful choices include 'helgrind' and
+	'drd', but you may use any tool recognized by your valgrind
+	installation.
+
+	Note that memcheck is run with the option --leak-check=no,
 	as the git process is short-lived and some errors are not
 	interesting. In order to run a single command under the same
 	conditions manually, you should set GIT_VALGRIND to point to