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author卜部昌平 <shyouhei@ruby-lang.org>2020-05-08 18:10:13 +0900
committer卜部昌平 <shyouhei@ruby-lang.org>2020-05-11 09:24:08 +0900
commitb85fd1d690b65efaa126cf9c24da73f31eee7a4e (patch)
treee9bb5dbc7cea460fa8f209308c798eb783a33167 /include/ruby/internal/attr/constexpr.h
parent0d88fe3a7278e3dab2675c1fe2c0f184d0624da2 (diff)
downloadruby-b85fd1d690b65efaa126cf9c24da73f31eee7a4e.tar.gz
mv include/ruby/{impl,internal}
Devs do not love "impl".
Diffstat (limited to 'include/ruby/internal/attr/constexpr.h')
-rw-r--r--include/ruby/internal/attr/constexpr.h85
1 files changed, 85 insertions, 0 deletions
diff --git a/include/ruby/internal/attr/constexpr.h b/include/ruby/internal/attr/constexpr.h
new file mode 100644
index 0000000000..4b6cc81e3b
--- /dev/null
+++ b/include/ruby/internal/attr/constexpr.h
@@ -0,0 +1,85 @@
+#ifndef RBIMPL_ATTR_CONSTEXPR_H /*-*-C++-*-vi:se ft=cpp:*/
+#define RBIMPL_ATTR_CONSTEXPR_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 `RBIMPL` or `rbimpl` 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 #RBIMPL_ATTR_CONSTEXPR.
+ */
+#include "ruby/impl/has/feature.h"
+#include "ruby/impl/compiler_is.h"
+#include "ruby/impl/token_paste.h"
+
+/** @cond INTERNAL_MACRO */
+#if ! defined(__cplusplus)
+# /* Makes no sense. */
+# define RBIMPL_HAS_ATTR_CONSTEXPR_CXX11 0
+# define RBIMPL_HAS_ATTR_CONSTEXPR_CXX14 0
+
+#elif defined(__cpp_constexpr)
+# /* https://isocpp.org/std/standing-documents/sd-6-sg10-feature-test-recommendations */
+# define RBIMPL_HAS_ATTR_CONSTEXPR_CXX11 (__cpp_constexpr >= 200704L)
+# define RBIMPL_HAS_ATTR_CONSTEXPR_CXX14 (__cpp_constexpr >= 201304L)
+
+#elif RBIMPL_COMPILER_SINCE(MSVC, 19, 0, 0)
+# define RBIMPL_HAS_ATTR_CONSTEXPR_CXX11 RBIMPL_COMPILER_SINCE(MSVC, 19, 00, 00)
+# define RBIMPL_HAS_ATTR_CONSTEXPR_CXX14 RBIMPL_COMPILER_SINCE(MSVC, 19, 11, 00)
+
+#elif RBIMPL_COMPILER_SINCE(SunPro, 5, 13, 0)
+# define RBIMPL_HAS_ATTR_CONSTEXPR_CXX11 (__cplusplus >= 201103L)
+# define RBIMPL_HAS_ATTR_CONSTEXPR_CXX14 (__cplusplus >= 201402L)
+
+#elif RBIMPL_COMPILER_SINCE(GCC, 4, 9, 0)
+# define RBIMPL_HAS_ATTR_CONSTEXPR_CXX11 (__cplusplus >= 201103L)
+# define RBIMPL_HAS_ATTR_CONSTEXPR_CXX14 (__cplusplus >= 201402L)
+
+#elif RBIMPL_HAS_FEATURE(cxx_relaxed_constexpr)
+# define RBIMPL_HAS_ATTR_CONSTEXPR_CXX11 1
+# define RBIMPL_HAS_ATTR_CONSTEXPR_CXX14 1
+
+#elif RBIMPL_HAS_FEATURE(cxx_constexpr)
+# define RBIMPL_HAS_ATTR_CONSTEXPR_CXX11 1
+# define RBIMPL_HAS_ATTR_CONSTEXPR_CXX14 0
+
+#else
+# /* :FIXME: icpc must have constexpr but don't know how to detect. */
+# define RBIMPL_HAS_ATTR_CONSTEXPR_CXX11 0
+# define RBIMPL_HAS_ATTR_CONSTEXPR_CXX14 0
+#endif
+/** @endcond */
+
+/** Wraps (or simulates) C++11 `constexpr`. */
+#if RBIMPL_HAS_ATTR_CONSTEXPR_CXX14
+# define RBIMPL_ATTR_CONSTEXPR(_) constexpr
+
+#elif RBIMPL_HAS_ATTR_CONSTEXPR_CXX11
+# define RBIMPL_ATTR_CONSTEXPR(_) RBIMPL_TOKEN_PASTE(RBIMPL_ATTR_CONSTEXPR_, _)
+# define RBIMPL_ATTR_CONSTEXPR_CXX11 constexpr
+# define RBIMPL_ATTR_CONSTEXPR_CXX14 /* void */
+
+#else
+# define RBIMPL_ATTR_CONSTEXPR(_) /* void */
+#endif
+
+/** Enables #RBIMPL_ATTR_CONSTEXPR iff. #RUBY_NDEBUG. */
+#if RUBY_NDEBUG
+# define RBIMPL_ATTR_CONSTEXPR_ON_NDEBUG(_) RBIMPL_ATTR_CONSTEXPR(_)
+#else
+# define RBIMPL_ATTR_CONSTEXPR_ON_NDEBUG(_) /* void */
+#endif
+
+#endif /* RBIMPL_ATTR_CONSTEXPR_H */