User-defined features vs. builtin features.

[tee3]

I am trying to add a local feature (<floating-point-abi>) for use with ARM processors (Cortex-R, Cortex-A, etc.).
I have a branch (tee3@74713c5) to add this to Boost.Build itself, but I am working on a project that cannot use the latest B2 or a custom-build B2 in the short term.

I have tried to work around this by adding the feature myself, but it does not seem to apply properly across the entire project. It sort of works, but not really. For something like Boost using the src/contrib/boost.jam module, the objects are built without knowledge of the <floating-point-abi> and so will link against the last built version, which may or may not match the current build in the project.

In my case, I have a B2 module that defines both additional values for existing features (<instruction-set> has some additional processors) as well as the new <floating-point-abi> feature. These appear in the build paths of most parts of the project, but not all. I believe that I can inject this using the toolset.add-requirements ( requirements * ) rule, although I think I have to add flags to <cflags> instead of directly how it is done in e.g. gcc.jam.

Is there a way to do this that I'm missing? I'd like to be able to add new features and values and have them apply across everything without having to update B2 directly.

[grafikrobot]

Using toolset.add-requirements is certainly one way to do it. Using it would look like:

toolset.add-requirements <instruction-set>xyz,<toolset>gcc:<cflags>-march=xyz ;
toolset.add-requirements <instruction-set>xyz,<toolset>gcc:<linkflags>-march=xyz ;

You would have to repeat that for all the toolsets and features you support. Another, way more hackish way is possibly to add to the toolset module definitions. For example:

using gcc ;
module gcc
{
  cpu-flags OPTIONS : x86 : xyz : -march=xyz ;
}

WARNING: That is totally off the cuff and untested code.

[tee3]

Thanks for your reply. I will see if that accomplishes my goals and let you know.

[tee3]

While my project still doesn't work as I expect, I wrote a small example project doing everything described here and it worked as I expected. The flags were added to the compiler command line and the feature appeared on the directory path of the build directories as it should.

My project is a bit more complicated than that, so I'm still stuck, but the cause does not appear to be the feature itself.

Thanks!

[tee3]

I did find the issue in my module, so just wanted to let you know that this all works as described in my more complex scenario. I have a module that adds values to existing features (<instruction-set>, etc.) as well as adding new features (<floating-point-abi>) if those values or features do not exist already.