From 5f57cb41f93a99f0528ac850b6910e9b8e6dbfaa Mon Sep 17 00:00:00 2001
From: Yuxuan Shui <yshuiv7@gmail.com>
Date: Wed, 19 Dec 2018 20:36:05 +0000
Subject: [PATCH] A bit more compiler dependent macros

Signed-off-by: Yuxuan Shui <yshuiv7@gmail.com>
---
 src/compiler.h | 74 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 74 insertions(+)

diff --git a/src/compiler.h b/src/compiler.h
index 75d3fcb..dca59e9 100644
--- a/src/compiler.h
+++ b/src/compiler.h
@@ -5,3 +5,77 @@
 #define auto         __auto_type
 #define likely(x)    __builtin_expect(!!(x), 1)
 #define unlikely(x)  __builtin_expect(!!(x), 0)
+
+#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
+
+#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(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