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Diffstat (limited to 'tools/testing/selftests/rseq/compiler.h')
| -rw-r--r-- | tools/testing/selftests/rseq/compiler.h | 62 |
1 files changed, 62 insertions, 0 deletions
diff --git a/tools/testing/selftests/rseq/compiler.h b/tools/testing/selftests/rseq/compiler.h new file mode 100644 index 000000000000..49d62fbd6dda --- /dev/null +++ b/tools/testing/selftests/rseq/compiler.h @@ -0,0 +1,62 @@ +/* SPDX-License-Identifier: LGPL-2.1-only OR MIT */ +/* + * rseq/compiler.h + * + * Work-around asm goto compiler bugs. + * + * (C) Copyright 2021 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com> + */ + +#ifndef RSEQ_COMPILER_H +#define RSEQ_COMPILER_H + +/* + * gcc prior to 4.8.2 miscompiles asm goto. + * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58670 + * + * gcc prior to 8.1.0 miscompiles asm goto at O1. + * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103908 + * + * clang prior to version 13.0.1 miscompiles asm goto at O2. + * https://github.com/llvm/llvm-project/issues/52735 + * + * Work around these issues by adding a volatile inline asm with + * memory clobber in the fallthrough after the asm goto and at each + * label target. Emit this for all compilers in case other similar + * issues are found in the future. + */ +#define rseq_after_asm_goto() asm volatile ("" : : : "memory") + +/* Combine two tokens. */ +#define RSEQ__COMBINE_TOKENS(_tokena, _tokenb) \ + _tokena##_tokenb +#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_ */ |