Commit Graph

3 Commits

Author SHA1 Message Date
Louis Dionne 92832e4889 [libc++] Enable <atomic> when threads are disabled
std::atomic is, for the most part, just a thin veneer on top of compiler
builtins. Hence, it should be available even when threads are not available
on the system, and in fact there has been requests for such support.

This patch:
- Moves __libcpp_thread_poll_with_backoff to its own header so it can
  be used in <atomic> when threads are disabled.
- Adds a dummy backoff policy for atomic polling that doesn't know about
  threads.
- Adjusts the <atomic> feature-test macros so they are provided even when
  threads are disabled.
- Runs the <atomic> tests when threads are disabled.

rdar://77873569

Differential Revision: https://reviews.llvm.org/D114109
2021-11-17 23:02:58 -05:00
Louis Dionne 6f6175d1c6 [libc++][NFC] Fix copy-paste errors in tests
The test precision_type.pass.cpp was a duplicate of precision.pass.cpp,
so it is removed. atomic_flag_test.pass.cpp was a duplicate of
atomic_flag_test_and_set.pass.cpp, so instead I wrote a proper
test for it. Those duplicate tests were detected with

     find libcxx ! -empty -type f -exec md5sum {} + | sort | uniq -w32 -dD
2021-08-18 08:54:18 -04:00
Olivier Giroux fc4bff0cd3 Update atomic feature macros, synopsis, signatures to match C++20. Improve test coverage for non-lock-free atomics. 2020-09-09 10:00:09 -07:00