Hi Anthony, Since Xiang already added support for NuttX on libcxx mainstream: https://reviews.llvm.org/D88718?id=303700
I think it is time to phase out my libcxx repository and we will stick to libcxx mainline. Do you agree on that? BR, Alan On 1/9/21, Anthony Merlino <anth...@vergeaero.com> wrote: > Thanks for the info Xiang! I was on the right track but it is good to have > some affirmation that I'm not missing something. > > The issue with the Arm maintained toolchain, as Greg has warned many times, > is its use of newlib. Are you doing anything to ensure the wrong math > library is not used? > > I will work on improving buildroot to also build and include libsupcxx.a. > > With Alan's modified version of libcxx, he disabled some exception logic > and maybe some other logic that was allowing me to build without libsupxx.a > entirely. > > Also, may I ask why we are building libcxx by manually grabbing the source > files and building it? Are we against just driving the build from their > existing build system? I ask because there are options in the way libcxx is > built that might be useful to us and we have to replicate all of that if we > just grab the source. > > > Best, > Anthony > > > On Sat, Jan 9, 2021, 7:32 AM Xiang Xiao <xiaoxiang781...@gmail.com> wrote: > >> On Fri, Jan 8, 2021 at 9:57 AM Anthony Merlino <anth...@vergeaero.com> >> wrote: >> >> > Hey all, >> > >> > Would someone be willing to share their experience with libcxx and >> > their >> > toolchain? >> >> >> This toolchain should work: >> >> https://developer.arm.com/tools-and-software/open-source-software/developer-tools/gnu-toolchain/gnu-rm >> >> >> > I've now caught up to the tip of master, which now downloads >> > and builds libcxx for me instead of using Alan's modified version. I am >> > facing an issue I've faced before, and would really love to properly >> > understand how this is supposed to work. >> > >> > My issues mostly center around libsupc++.a >> > >> > Currently, my build fails because it can't find libsupc++. From my >> > understanding, this should be provided by my toolchain. But I am using >> > a >> > toolchain built by the NuttX buildroot and it does not build the C++ >> > libraries. I am not using RTTI or exceptions, so I don't need what >> > >> >> libsupc++.a doesn't only provide RTTI and exectpions, but also provide >> some >> basic functions called by compiler: >> >> https://github.com/gcc-mirror/gcc/tree/master/libstdc%2B%2B-v3/libsupc%2B%2B >> >> libsupc++ provides, however the Kconfig option >> > `[ ] Have libsupc++ (required)` >> > says, it's required. >> > >> > What's the right answer here? What are others doing about this? >> > >> > >> Three methods you can try: >> >> 1. Switch to the ARM maintained toolchain >> 2. Build libsupc++.a for NuttX toolchain >> 3. Enhance NuttX's libc++ runtime support >> >> >> https://github.com/apache/incubator-nuttx/tree/master/libs/libxx >> >> >> > Is getting NuttX buildroot to build and provide libsupc++.a the *right* >> > solution? >> > >> > >> Yes, a complete toolchain should provide libsupc++.a. libsupc++.a just >> like >> libgcc.a should part of toolchain, not part of c/c++ library >> implemetnation, because libsupc++.a tightly couple with the implementaion >> detail of compiler. >> >> >> > Do we need to change how libcxx is built in this case? >> > >> > >> https://libcxx.llvm.org/docs/BuildingLibcxx.html#using-alternate-abi-libraries >> > >> > >> Then you need port the libcxxrt: >> https://github.com/libcxxrt/libcxxrt >> >> >> > Thank you! >> > >> > Anthony >> > >> >
