How to run the tests of clang

Hi,all:
i want run the test below <llvm_src>/tools/clang/test/CodeGenOpenCL,but i got a error when i use command line like this:
./llvm-lit <llvm_src>/tools/clang/test/CodeGenOpenCL/address-spaces.cl
if anyone can tell me how to run the tests?
thanks!

regard,
ccwang