diff options
Diffstat (limited to 'include/ruby/impl/attr/artificial.h')
| -rw-r--r-- | include/ruby/impl/attr/artificial.h | 46 |
1 files changed, 46 insertions, 0 deletions
diff --git a/include/ruby/impl/attr/artificial.h b/include/ruby/impl/attr/artificial.h new file mode 100644 index 0000000000..f5450e3467 --- /dev/null +++ b/include/ruby/impl/attr/artificial.h @@ -0,0 +1,46 @@ +#ifndef RUBY3_ATTR_ARTIFICIAL_H /*-*-C++-*-vi:se ft=cpp:*/ +#define RUBY3_ATTR_ARTIFICIAL_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_ATTR_ARTIFICIAL. + * + * ### Q&A ### + * + * - Q: What is this attribute? I don't get what GCC manual is talking about. + * + * - A: In short it is an attribute to manipulate GDB backtraces. The + * attribute makes the best sense when it comes with + * __attribute__((always_inline)). When a function annotated with this + * attribute gets inlined, and when you somehow look at a backtrace which + * includes such inlined call site, then the backtrace shows the caller + * and not the callee. This is handy for instance when an identical + * function is inlined more than once in a single big function. On such + * case it gets vital to know where the inlining happened in the callee. + * See also https://stackoverflow.com/a/21936099 + */ +#include "ruby/3/has/attribute.h" + +/** Wraps (or simulates) `__attribute__((artificial))` */ +#if RUBY3_HAS_ATTRIBUTE(artificial) +# define RUBY3_ATTR_ARTIFICIAL() __attribute__((__artificial__)) +#else +# define RUBY3_ATTR_ARTIFICIAL() /* void */ +#endif + +#endif /* RUBY3_ATTR_ARTIFICIAL_H */ |