diff options
Diffstat (limited to 'include/ruby/impl/assume.h')
| -rw-r--r-- | include/ruby/impl/assume.h | 90 |
1 files changed, 90 insertions, 0 deletions
diff --git a/include/ruby/impl/assume.h b/include/ruby/impl/assume.h new file mode 100644 index 0000000000..98059d7cbf --- /dev/null +++ b/include/ruby/impl/assume.h @@ -0,0 +1,90 @@ +#ifndef RUBY3_ASSUME_H /*-*-C++-*-vi:se ft=cpp:*/ +#define RUBY3_ASSUME_H +/** + * @file + * @author Ruby developers <ruby-core@ruby-lang.org> + * @copyright This file is a part of the programming language Ruby. + * Permission is hereby granted, to either redistribute and/or + * modify this file, provided that the conditions mentioned in the + * file COPYING are met. Consult the file for details. + * @warning Symbols prefixed with either `RUBY3` or `ruby3` are + * implementation details. Don't take them as canon. They could + * rapidly appear then vanish. The name (path) of this header file + * is also an implementation detail. Do not expect it to persist + * at the place it is now. Developers are free to move it anywhere + * anytime at will. + * @note To ruby-core: remember that this header can be possibly + * recursively included from extension libraries written in C++. + * Do not expect for instance `__VA_ARGS__` is always available. + * We assume C99 for ruby itself but we don't assume languages of + * extension libraries. They could be written in C++98. + * @brief Defines #RUBY3_ASSUME / #RUBY3_UNREACHABLE. + * + * These macros must be defined at once because: + * + * - #RUBY3_ASSUME could fallback to #RUBY3_UNREACHABLE. + * - #RUBY3_UNREACHABLE could fallback to #RUBY3_ASSUME. + */ +#include "ruby/3/config.h" +#include "ruby/3/cast.h" +#include "ruby/3/compiler_since.h" +#include "ruby/3/has/builtin.h" +#include "ruby/3/warning_push.h" + +/** @cond INTERNAL_MACRO */ +#if RUBY3_COMPILER_SINCE(MSVC, 13, 10, 0) +# define RUBY3_HAVE___ASSUME + +#elif RUBY3_COMPILER_SINCE(Intel, 13, 0, 0) +# define RUBY3_HAVE___ASSUME +#endif +/** @endcond */ + +/** Wraps (or simulates) `__builtin_unreachable`. */ +#if RUBY3_HAS_BUILTIN(__builtin_unreachable) +# define RUBY3_UNREACHABLE_RETURN(_) __builtin_unreachable() + +#elif defined(RUBY3_HAVE___ASSUME) +# define RUBY3_UNREACHABLE_RETURN(_) return (__assume(0), (_)) + +#else +# define RUBY3_UNREACHABLE_RETURN(_) return (_) +#endif + +/** Wraps (or simulates) `__builtin_unreachable`. */ +#if RUBY3_HAS_BUILTIN(__builtin_unreachable) +# define RUBY3_UNREACHABLE __builtin_unreachable + +#elif defined(RUBY3_HAVE___ASSUME) +# define RUBY3_UNREACHABLE() __assume(0) +#endif + +/** Wraps (or simulates) `__assume`. */ +#if RUBY3_COMPILER_SINCE(Intel, 13, 0, 0) +# /* icc warnings are false positives. Ignore them. */ +# /* "warning #2261: __assume expression with side effects discarded" */ +# define RUBY3_ASSUME(expr) \ + RUBY3_WARNING_PUSH() \ + RUBY3_WARNING_IGNORED(2261) \ + __assume(expr) \ + RUBY3_WARNING_POP() + +#elif defined(RUBY3_HAVE___ASSUME) +# define RUBY3_ASSUME __assume + +#elif RUBY3_HAS_BUILTIN(__builtin_assume) +# define RUBY3_ASSUME __builtin_assume + +#elif ! defined(RUBY3_UNREACHABLE) +# define RUBY3_ASSUME(_) RUBY3_CAST((void)(_)) + +#else +# define RUBY3_ASSUME(_) \ + (RB_LIKELY(!!(_)) ? RUBY3_CAST((void)0) : RUBY3_UNREACHABLE()) +#endif + +#if ! defined(RUBY3_UNREACHABLE) +# define RUBY3_UNREACHABLE() RUBY3_ASSUME(0) +#endif + +#endif /* RUBY3_ASSUME_H */ |