diff options
| author | Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | 2023-06-27 11:29:21 -0400 |
|---|---|---|
| committer | Shuah Khan <skhan@linuxfoundation.org> | 2023-08-08 14:42:01 -0600 |
| commit | d6aaa23a2b33d81502e18dfe25ee1847b76b7bf6 (patch) | |
| tree | 8e9d4dce56678e2f5f881ab1b8308796573465e3 /tools | |
| parent | c0d87e43a6627b7ef3dcaf4ac5fb9996e3ac31a9 (diff) | |
selftests/rseq: Implement rseq_unqual_scalar_typeof
Allow defining variables and perform cast with a typeof which removes
the volatile and const qualifiers.
This prevents declaring a stack variable with a volatile qualifier
within a macro, which would generate sub-optimal assembler.
This is imported from the "librseq" project.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
Diffstat (limited to 'tools')
| -rw-r--r-- | tools/testing/selftests/rseq/compiler.h | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/tools/testing/selftests/rseq/compiler.h b/tools/testing/selftests/rseq/compiler.h index f47092bddeba..49d62fbd6dda 100644 --- a/tools/testing/selftests/rseq/compiler.h +++ b/tools/testing/selftests/rseq/compiler.h @@ -33,4 +33,30 @@ #define RSEQ_COMBINE_TOKENS(_tokena, _tokenb) \ RSEQ__COMBINE_TOKENS(_tokena, _tokenb) +#ifdef __cplusplus +#define rseq_unqual_scalar_typeof(x) \ + std::remove_cv<std::remove_reference<decltype(x)>::type>::type +#else +#define rseq_scalar_type_to_expr(type) \ + unsigned type: (unsigned type)0, \ + signed type: (signed type)0 + +/* + * Use C11 _Generic to express unqualified type from expression. This removes + * volatile qualifier from expression type. + */ +#define rseq_unqual_scalar_typeof(x) \ + __typeof__( \ + _Generic((x), \ + char: (char)0, \ + rseq_scalar_type_to_expr(char), \ + rseq_scalar_type_to_expr(short), \ + rseq_scalar_type_to_expr(int), \ + rseq_scalar_type_to_expr(long), \ + rseq_scalar_type_to_expr(long long), \ + default: (x) \ + ) \ + ) +#endif + #endif /* RSEQ_COMPILER_H_ */ |