On 03/12/19 23:38 +0100, Paul M. Bendixen wrote:
Hello I've made an implementation of P0829 and tested it with gcc for avr.
This is great, thanks! What's the status of libstdc++ for AVR? If I understand correctly, it doesn't build by default when GCC is configured for AVR. Are you overriding that, or just copying the headers somewhere and including them in your programs?
I've included the patch and I believe it might need some modification. Should I rather just maintain my own fork until P0829 is a bit further? (It is currently being split into smaller proposals).
Yes, I think it's too early to actually make this change. Our current !_GLIBCXX_HOSTED build conforms to the requirements of a freestanding implementation (for anything from C++98 to C++17) so I'd prefer not to mess with that drastically until the P0829 work has made more progress. Despite that, I'm very happy to see somebody take on the task, and will be glad to apply a patch like this when the time is right.
I have not included further tests, nor actually run the tests since everything is in header files is only includes of already existing libstdc++ code.
If we were serious about improving our freestanding support, we'd need to partition the testsuite into the parts that should pass for freestanding, and mark all the other tests UNSUPPORTED. That would mean we could run tests for a freestanding build and not get thousands of failures for tests that are not expected to work for freestanding. That would be a big project though. Your patch is mostly just adding #if in various places, not adding new code, and so I'm not sure it needs a copyright assignment (the changes probably aren't copyrightable anyway). But if you plan to contribute to GCC it would be good to get an assignment in place (if you don't have one already). See https://gcc.gnu.org/contribute.html#legal for more information, and feel free to contact me directly if you have any questions or if you want to start the process. Thanks again for the patch. Please do keep working on it as the P0829 work evolves, so that we can integrate it with libstdc++ at some point.
