Summary:
See D60593 for further information.
This patch pulls out the mutex implementation and the required definitions file.
We implement our own mutex for GWP-ASan currently, because:
1. We must be compatible with the sum of the most restrictive elements of the supporting allocator's build system. Current targets for GWP-ASan include Scudo (on Linux and Fuchsia), and bionic (on Android).
2. Scudo specifies `-nostdlib++ -nonodefaultlibs`, meaning we can't use `std::mutex` or `mtx_t`.
3. We can't use `sanitizer_common`'s mutex, as the supporting allocators cannot afford the extra maintenance (Android, Fuchsia) and code size (Fuchsia) overheads that this would incur.
In future, we would like to implement a shared base mutex for GWP-ASan, Scudo and sanitizer_common. This will likely happen when both GWP-ASan and Scudo standalone are not in the development phase, at which point they will have stable requirements.
Reviewers: vlad.tsyrklevich, morehouse, jfb
Reviewed By: morehouse
Subscribers: dexonsmith, srhines, cfe-commits, kubamracek, mgorny, cryptoad, jfb, #sanitizers, llvm-commits, vitalybuka, eugenis
Tags: #sanitizers, #llvm, #clang
Differential Revision: https://reviews.llvm.org/D61923
llvm-svn: 362138
5f0f4e3ae0