Enable using the toolchain (llvm) provided FileCheck.

tools/llvm_file_check_wrapper.py

+# Copyright (c) 2011 The Native Client Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+#
+# We want to run FileCheck | <cmd_line>, but all that as a parameter
+# to the python test wrapper (see CommandTest in ../SConstruct).
+# Without this wrapper for FileCheck, the command interpreter takes
+# everything on the left of '|' and pipes it to everything on the right,
+# which is not what we want.
+
+import subprocess
+import sys
+
+def Main(args):
+  if len(args) < 3:
+    print "llvm_file_check_wrapper <filecheck> <check_file> <cmd_line>"
+    print "Where:"
+    print "<filecheck> is the path to FileCheck"
+    print "<check_file> is a text file containing 'CHECK' statements"
+    print "<cmd_line> is the command line to use as input to FileCheck"
+    return 1
+
+  file_check=args[0]
+  check_file=args[1]
+  what_to_run=args[2:]
+
+  what_to_run_proc = subprocess.Popen(what_to_run, stdout=subprocess.PIPE)
+  file_check_proc = subprocess.check_output((file_check, check_file),
+          stdin=what_to_run_proc.stdout)
+  what_to_run_proc.wait()
+
+if __name__ == '__main__':
+  sys.exit(Main(sys.argv[1:]))