Hi all, there was a commit a while ago that effectively forces all LLVM projects to use libatomics on 32bit platforms. It is completely necessary for clang and LLVM, of limited usefulness for libc++ (<atomics> test cases) and necessary for LLDB right now. The only instance in LLDB is include/Utility/Timer.h for nanosecond-precise time accounting. While the code is correct, it will be secretly using a mutex in the implementation and therefore not be wait-free. This feels like somewhat of a bad idea for an accounting tool, so I would like to:
(a) Make the mutex explicit if 64bit operations are not lock-free. or (b) Weaken the consistency constraints to provide eventually-consistent times by splitting the field into explicit 32bit chunks. This makes the write side get predictable timings at the expensive of the summaries being potentially off a bit in the case of races. Joerg _______________________________________________ lldb-dev mailing list lldb-dev@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-dev
