Mix Testing: Specifying and Testing ABI Compatibility of C/C++ Atomics Implementations
summary
Tooling and results: a new testing technique compiles individual C/C++ atomic operations with multiple mappings, links the permutations, and checks whether composed binaries exhibit forbidden source outcomes; the implemented atomic-mixer tool generates and runs these mixed binaries (simulation or hardware). It reproduces a known non-mixing bug, finds four previously-unknown mixing bugs in LLVM and GCC plus one prospective JVM mapping issue, and helps validate a newly specified Armv8 atomics ABI. The technique is exponential in mappings and operations; several bugs are fixed or triaged.
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chapters (7)
- 0:00Mix testing for C/C++ atomics
- 4:18High-level overview
- 7:27Mix testing technique and Atomic Mixer
- 9:11Mixing bugs in atomics
- 10:58ARM’s spec to prevent mixing bugs
- 12:46Summary of findings
- 13:30Q&A
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