Pass -mtls-use-call when building libraries used in IRT.

src/untrusted/irt/check_tls.py

Index: src/untrusted/irt/check_tls.py
diff --git a/src/untrusted/irt/check_tls.py b/src/untrusted/irt/check_tls.py
new file mode 100644
index 0000000000000000000000000000000000000000..de7a746e83b260239efc8bdee175b6ca65100d00
--- /dev/null
+++ b/src/untrusted/irt/check_tls.py
@@ -0,0 +1,24 @@
+# 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.
+
+# A simple program to run objdump on a file and assert that '%gs'
+# appears nowhere in it.  This ensures that the direct register access
+# style of TLS is not being used in the IRT blob.
+
+import subprocess
+import sys
+
+
+def Main(args):
+  objdump = args[0]

[Mark Seaborn, 2011/04/13 20:32:30]

Maybe also do "assert len(args) == 2" (or a more informative check).

+  obj_file = args[1]
+  proc = subprocess.Popen([objdump, '-d', obj_file], stdout=subprocess.PIPE)
+  for line in proc.stdout:
+    if '%gs' in line:
+      print 'TLS access found: %s' % line

[Mark Seaborn, 2011/04/13 20:32:30]

Can add some more description to the error?

e.g. "x86-32 direct TLS access found.  This means that a library was linked in
that was not compiled with '-mtls-use-call'."

This error is most likely to be triggered on the trybots when someone changes a
library and is not expecting to see this error.

+      exit(1)

[Mark Seaborn, 2011/04/13 20:32:30]

I think sys.exit is the more correct function to use.

+
+
+if __name__ == '__main__':
+  Main(sys.argv[1:])