Support collecting perf profiles remotely (#275)
If we're running tests on a remote machine with -DTEST_SUITE_REMOTE_HOST and generate a perf profile with `lit --param profile=perf`, currently the profile step will be run on the local machine and fail.
This patch fixes this by running the profile step on the remote, as well as copying the generated profiles back to the host so tools like LNT can inspect them.
There's two parts to this, first we need to run the remote module after the perf (and hpmcount) module so that we can wrap the profile step with ssh etc.
Secondly, we need to scp over the generated .perf_data files like we also do for the profilegen.py module. However today this is also done as part of the profile step which we now need to start running over ssh. So to fix this, this adds a new "profile collect" step that runs after the profile step, but always runs on the local machine.
I've tested this out on a remote build configured with `-DTEST_SUITE_REMOTE_HOST=... -DTEST_SUITE_USE_PERF=ON -DTEST_SUITE_PROFILE_GENERATE=ON -DTEST_SUITE_USE_IR_PGO=ON` and running the tests with `lit --param profile=perf`, and it seems to work.
4 files changed
