As previously noted in nsan.cpp we can implement
optimized variants of `__nsan_copy_values` and
`__nsan_set_value_unknown` if a memory operation
size is known.
Now the instrumentation creates calls to optimized functions if there is
4, 8 or 16-byte memory operation like
`memset(X, value, 4/8/16)` or `memcpy(dst, src, 4/8/16)`
nsan.cpp provides definitions of the optimized functions.
This PR introduces the numerical sanitizer originally proposed by
Clement Courbet on https://reviews.llvm.org/D97854
(https://arxiv.org/abs/2102.12782).
The main additions include:
- Migration to LLVM opaque pointers
- Migration to various updated APIs
- Extended coverage for LLVM instructions/intrinsics
- Code refactoring
The tool is still very experimental, the coverage (e.g. for intrinsics /
library functions) is incomplete.
Link: https://discourse.llvm.org/t/rfc-revival-of-numerical-sanitizer/79601
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Co-authored-by: Fangrui Song <i@maskray.me>
