picom/src/compiler.h

// SPDX-License-Identifier: MPL-2.0
// Copyright (c) 2018 Yuxuan Shui <yshuiv7@gmail.com>
#pragma once

#ifdef HAS_STDC_PREDEF_H
#include <stdc-predef.h>
#endif

#define auto           __auto_type
#define likely(x)      __builtin_expect(!!(x), 1)
#define unlikely(x)    __builtin_expect(!!(x), 0)
#define likely_if(x)   if (likely(x))
#define unlikely_if(x) if (unlikely(x))

#ifndef __has_attribute
# if __GNUC__ >= 4
#  define __has_attribute(x) 1
# else
#  define __has_attribute(x) 0
# endif
#endif

#if __has_attribute(const)
# define attr_const __attribute__((const))
#else
# define attr_const
#endif

#if __has_attribute(format)
# define attr_printf(a, b) __attribute__((format(printf, a, b)))
#else
# define attr_printf(a, b)
#endif

#if __has_attribute(pure)
# define attr_pure __attribute__((pure))
#else
# define attr_pure
#endif

#if __has_attribute(unused)
# define attr_unused __attribute__((unused))
#else
# define attr_unused
#endif

#if __has_attribute(warn_unused_result)
# define attr_warn_unused_result __attribute__((warn_unused_result))
#else
# define attr_warn_unused_result
#endif
// An alias for conveninence
#define must_use attr_warn_unused_result

#if __has_attribute(nonnull)
# define attr_nonnull(...) __attribute__((nonnull(__VA_ARGS__)))
# define attr_nonnull_all __attribute__((nonnull))
#else
# define attr_nonnull(...)
# define attr_nonnull_all
#endif

#if __has_attribute(returns_nonnull)
# define attr_ret_nonnull __attribute__((returns_nonnull))
#else
# define attr_ret_nonnull
#endif

#if __has_attribute(deprecated)
# define attr_deprecated __attribute__((deprecated))
#else
# define attr_deprecated
#endif

#if __has_attribute(malloc)
# define attr_malloc __attribute__((malloc))
#else
# define attr_malloc
#endif

#if __STDC_VERSION__ >= 201112L
# define attr_noret _Noreturn
#else
# if __has_attribute(noreturn)
#  define attr_noret __attribute__((noreturn))
# else
#  define attr_noret
# endif
#endif

#if defined(__GNUC__) || defined(__clang__)
# define unreachable __builtin_unreachable()
#else
# define unreachable do {} while(0)
#endif

#ifndef __STDC_NO_THREADS__
# include <threads.h>
#elif __STDC_VERSION__ >= 201112L
# define thread_local _Thread_local
#elif defined(__GNUC__) || defined(__clang__)
# define thread_local __thread
#else
# define thread_local _Pragma("GCC error \"No thread local storage support\"") __error__
#endif

typedef unsigned long ulong;
typedef unsigned int uint;

static inline int popcount(uint x) {
	return __builtin_popcount(x);
}