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46 lines
2.4 KiB
C++
46 lines
2.4 KiB
C++
/** \noop-*-C++-*-vi:ft=cpp
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* @file
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* @author Ruby developers <ruby-core@ruby-lang.org>
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* @copyright This file is a part of the programming language Ruby.
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* Permission is hereby granted, to either redistribute and/or
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* modify this file, provided that the conditions mentioned in the
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* file COPYING are met. Consult the file for details.
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* @warning Symbols prefixed with either `RUBY3` or `ruby3` are
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* implementation details. Don't take them as canon. They could
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* rapidly appear then vanish. The name (path) of this header file
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* is also an implementation detail. Do not expect it to persist
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* at the place it is now. Developers are free to move it anywhere
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* anytime at will.
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* @note To ruby-core: remember that this header can be possibly
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* recursively included from extension libraries written in C++.
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* Do not expect for instance `__VA_ARGS__` is always available.
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* We assume C99 for ruby itself but we don't assume languages of
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* extension libraries. They could be written in C++98.
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* @brief Defines #RUBY3_ATTR_ARTIFICIAL.
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*
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* ### Q&A ###
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*
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* - Q: What is this attribute? I don't get what GCC manual is talking about.
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*
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* - A: In short it is an attribute to manipulate GDB backtraces. The
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* attribute makes the best sense when it comes with
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* __attribute__((always_inline)). When a function annotated with this
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* attribute gets inlined, and when you somehow look at a backtrace which
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* includes such inlined call site, then the backtrace shows the caller
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* and not the callee. This is handy for instance when an identical
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* function is inlined more than once in a single big function. On such
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* case it gets vital to know where the inlining happened in the callee.
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* See also https://stackoverflow.com/a/21936099
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*/
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#include "ruby/3/has/attribute.h"
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/** Wraps (or simulates) `__attribute__((artificial))` */
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#if defined(RUBY3_ATTR_ARTIFICIAL)
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# /* Take that. */
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#elif RUBY3_HAS_ATTRIBUTE(artificial)
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# define RUBY3_ATTR_ARTIFICIAL() __attribute__((__artificial__))
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#else
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# define RUBY3_ATTR_ARTIFICIAL() /* void */
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#endif
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