Proposal: jtreg tests with native components

[Jonathan Gibbons]

I'll quibble over the phrase "the same makefile logic".

I think it is OK to use the same Makefile infrastructure (e.g. the 
configure.sh mechanism) and the same top level Makefile, but at some 
level this is going to need to be distinct Makefile logic specific to 
compiling the code for the tests.

I agree with the general concept of pre-building binaries, but it would 
be good to see the next level of detail:

-- where is the source code for the native code of the tests
-- is it one library per test, or what
-- what sort of hierarchy do the libraries end up in.

I am also concerned for the developer experience.  One of the 
characteristics of the jtreg design has always been that it is 
dev-friendly, meaning it is easy and fast for developers to edit a test 
and rerun it.    For myself, I don't work on native code, or on repos 
containing native code, so I'd be interested to hear how this will 
impact developers working on tests, and on those folk that simply want 
to run the tests.

-- Jon


On 04/25/2014 05:02 AM, Staffan Larsen wrote:
> There are a couple of jtreg tests today that depend on native components (either JNI libraries or executables). These are handled in one of two ways:
>
> 1) The binaries are pre-compiled and checked into the repository (often inside jar files).
> 2) The test will try to invoke a compiler (gcc, cl, …) when the test is being run.
>
> Neither of these are very good solutions. #1 makes it hard to run the setup the test for all platforms and requires binaries in the source control system. #2 is hit-and-miss: the correct compiler may or may not be installed on the test machine, and the approach requires platform specific logic to be maintained.
>
> I would like to propose that these native components are instead compiled when the product is built by the same makefile logic as the product. At product build time we know we have access to the (correct) compilers and we have excellent support in the makefiles for building on all platforms.
>
> If we build the native test components together with the product, we also have to take care of distributing the result together with the product when we do testing across a larger number of machines. We will also need a way to tell the jtreg tests where these pre-built binaries are located.
>
> I suggest that at the end of a distributed build run, the pre-built test binaries are packaged in a zip or tar file (just like the product bits) and stored next to the product bundles. When we run distributed tests, we need to pick up the product bundle and the test bundle before the testing is started.
>
> To tell the tests where the native code is, I would like to add a flag to jtreg to point out the path to the binaries. This should cause jtreg to set java.library.path before invoking a test and also set a test.* property which can be used by test to find it’s native components.
>
> This kind of setup would make it easier to add and maintain tests that have a native component. I think this will be especially important as more tests are written using jtreg in the hotspot repository.
>
> Thoughts on this? Is the general approach ok? There are lots of details to be figured out, but at this stage I would like to hear feedback on the idea as such.
>
> Thanks,
> /Staffan
>