[lldb-dev] Questions about the LLDB testsuite and improving its reliability

Davide Italiano via lldb-dev lldb-dev at lists.llvm.org
Wed Jan 17 13:02:52 PST 2018

On Wed, Jan 17, 2018 at 12:32 PM, Adrian Prantl via lldb-dev
<lldb-dev at lists.llvm.org> wrote:
> Hi lldb-dev!
> I've been investigating some spurious LLDB test suite failures on http://green.lab.llvm.org/green/ that had to do with build artifacts from previous runs lying around in the test directories and this prompted me to ask a couple of general noob questions about the LLDB testsuite.
> My understanding is that all execution tests are compiled using using `make` in-tree. I.e.: the test driver (dotest.py) effectively executes something equivalent to `cd $srcdir/packages/.../mytest && make`. And it does this in a serial fashion for all configurations (dwarf, dSYM, dwo, ...) and relies on the `clean` target to be implemented correctly.
> I don't understand all the design decisions that went into the LLDB testsuite, but my naive intuition tells me that this is sub-optimal (because of the serialization of the configurations) and dangerous (because it relies on make clean being implemented correctly). It seems to me that a better approach would be to create a separate build directory for each test variant and then invoke something like `cd $builddir/test/mytest.dwarf && make -C $srcdir/packages/.../mytest`. This way all configurations can build in parallel, and we can simply nuke the build directory afterwards and this way get rid of all custom implementations of the `clean` target.
> - Is this already possible, and/or am I misunderstanding how it works?
> - Would this be a goal that is worthwhile to pursue?
> - Is there a good reason why we are not already doing it this way?

As we're discussing lldb test suite changes, another detail that I
find a little weird is that every time you execute the test suite you
get a new build directory named after the time at which you run the
It would be much much better IMHO to just have a `log/` generic
directory where the failures are logged, and those who want to
override this setting can just pass a flag.


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