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- /* 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_ */
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