hipThreads testing timeout

The hipThreads test suite is adapted from the libc++ thread tests. Each test compiles to its own executable and runs the primitives inside a GPU kernel before checking its results.

The hipThreads test suite runs under lit, the LLVM Integrated Tester. lit compiles each test with hipcc and runs the executables using the run.py wrapper.

Because the tests in the suite run concurrency primitives on the device, a test can hang instead of finishing. For example, a thread that waits on a mutex that’s never released will stay blocked.

To prevent hanging, tests will be terminated after 30s and marked as having failed.

The timeout value is configurable through the HIPTHREADS_TEST_TIMEOUT environment variable.

For this variable to take effect, it must be set before lit:

export HIPTHREADS_TEST_TIMEOUT=120
lit -a -v -j 1 test/

Setting HIPTHREADS_TEST_TIMEOUT to 0 disables the timeout.