/* 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_ */