Make loader.cpp compatible with glibc <= 2.17

[JiayiFeng]

In the current loader.cpp, the symbol __cxa_thread_atexit_impl is introduced by extern "C": https://github.com/pytorch/multipy/blob/main/multipy/runtime/loader.cpp#L247-L248

However, this symbol is exposed in libc.so.6 only when glibc version is >=2.18. With old glibc, compile fails.

In this PR, the problem is solved by replacing __cxa_thread_atexit_impl with __cxxabiv1::__cxa_thread_atexit.

The function __cxxabiv1::__cxa_thread_atexit is a simple wrapper of __cxa_thread_atexit_impl and does exactly the same job: https://github.com/gcc-mirror/gcc/blob/16e2427f50c208dfe07d07f18009969502c25dc8/libstdc%2B%2B-v3/libsupc%2B%2B/atexit_thread.cc#L41-L47. The function is declared in the cxxabi.h. So we can use it by include <cxxabi.h> and the code no longer depends on glibc version.

[facebook-github-bot]

Hi @JiayiFeng!

Thank you for your pull request and welcome to our community.

Action Required

In order to merge any pull request (code, docs, etc.), we require contributors to sign our Contributor License Agreement, and we don't seem to have one on file for you.

Process

In order for us to review and merge your suggested changes, please sign at https://code.facebook.com/cla. If you are contributing on behalf of someone else (eg your employer), the individual CLA may not be sufficient and your employer may need to sign the corporate CLA.

Once the CLA is signed, our tooling will perform checks and validations. Afterwards, the pull request will be tagged with CLA signed. The tagging process may take up to 1 hour after signing. Please give it that time before contacting us about it.

If you have received this in error or have any questions, please contact us at cla@fb.com. Thanks!

[codecov]

Codecov Report

Merging #173 (902b3d7) into main (5562304) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main     #173   +/-   ##
=======================================
  Coverage   89.06%   89.06%           
=======================================
  Files          67       67           
  Lines        3888     3888           
=======================================
  Hits         3463     3463           
  Misses        425      425           

📣 We’re building smart automated test selection to slash your CI/CD build times. Learn more

[d4l3k]

Nice catch -- was looking for a replacement for that but missed the cxxabi.h file

We do need to have the CLA signed before we can merge -- otherwise the code looks good

[facebook-github-bot]

Thank you for signing our Contributor License Agreement. We can now accept your code for this (and any) Meta Open Source project. Thanks!

[facebook-github-bot]

@d4l3k has imported this pull request. If you are a Meta employee, you can view this diff on Phabricator.