Question: Incremental builds for multiple build configurations side-by-side

Hello, this is not a bug, but a beginner's question.

I would like to work in a workspace, editing code which has to run on multiple architectures. There are builds working with eg: bst --option arch amd64 build mypackage.bst.

Until now (without bst) we had a CMake build directory with subdirectories for each architecture: build/mipsel or build/ppc. Each of these were configured seperately with CMake -D... --CMAKE_TOOLCHAIN_FILE=... ../.. -GNinja. For the build we just had to change to the respective builddir and issue: ninja all. This was convenient, since it allows incremental builds seperately for each architecture, using the same source.

How can I emulate this using workspaces in bst?

I have tried:

• Dumbly just building with the different arch option: ``bst --option arch i368 build mypackage.bst```. This works, but completely rebuilds and reconfigures the current _builddir. So no incremental builds.
• I've created a condition in mypackage.bst (kind: cmake) and set a different builddir dependent on the arch value (arch=i386:_builddir_i386, arch=amd64:_builddir_amd64). This does not work. When I change the arch option for the build to another value (eg. from i386 to amd64), bst only wants to issue: cmake --build _builddir_amd64. This cannot work, because the previous run only configured _builddir_i386 but not _builddir_amd64. So this won't be a solution.

Are there any other possibilities I could try?

How do others work efficiently with bst if they support multiple architectures? Is this scenario even supported by bst yet?

Thanks for any answers and help, regards Marc

To clarify: actually my question is about how to efficiently work on code with multiple build configurations simultaneously.

It could also be any other build option like eg. building a release vs. debug configuration. This however is maybe a bad example as releases will mostly be clean builds and not happen that often.

In my situation I have to make sure the code builds (and also runs) on multiple targets. This means it should be fast rountrips.

changed title from Question: How to have parallel builds for different architectures to Question: Incremental builds for multiple build configurations side-by-side

The first time you build with a workspace, bst runs the configuration and build commands etc. But on subsequent builds only the build functions are run. unless the workspace is reset, you do not want to do a full reset as that would lose the incremental work, so a soft reset should be used.

When you want to switch arch you could try bst workspace reset --soft mypackage.bst before running bst --option arch arm64 build mypackage.bst. I am not sure if you will need to do this every time you switch or just the first time you switch to a new arch.

I have used bst workspace reset --soft a few times but not in such a complex situation, if this dose not work we might need slightly more info to help. I tend to use it if i have updated the dependencies but still want a incremental build.

Hi, this was helpful and behaves actually more or less the way I would like, as much as I can say right now. I had the hope this would be like an out of the box experience, automatically managed. Thanks

closed

mentioned in issue #963 (closed)