--- deliantra/server/include/compiler.h	2009/11/07 18:30:05	1.1
+++ deliantra/server/include/compiler.h	2016/11/18 04:46:35	1.17
@@ -1,35 +1,37 @@
 /*
  * This file is part of Deliantra, the Roguelike Realtime MMORPG.
- * 
- * Copyright (©) 2009 Marc Alexander Lehmann / Robin Redeker / the Deliantra team
- * 
+ *
+ * Copyright (©) 2009,2010,2011,2012,2013,2014,2015,2016 Marc Alexander Lehmann / Robin Redeker / the Deliantra team
+ *
  * Deliantra is free software: you can redistribute it and/or modify it under
  * the terms of the Affero GNU General Public License as published by the
  * Free Software Foundation, either version 3 of the License, or (at your
  * option) any later version.
- * 
+ *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  * GNU General Public License for more details.
- * 
+ *
  * You should have received a copy of the Affero GNU General Public License
  * and the GNU General Public License along with this program. If not, see
  * <http://www.gnu.org/licenses/>.
- * 
+ *
  * The authors can be reached via e-mail to <support@deliantra.net>
  */
 
 #ifndef COMPILER_H
 #define COMPILER_H
 
-#if __GNUC__ >= 3
+#define GCC_VERSION(major,minor) (__GNUC__ > (major) || (__GNUC__ == (major) && __GNUC_MINOR__ >= (minor)))
+
+#if GCC_VERSION(3,0)
 # define attribute(attrlist) __attribute__(attrlist)
 #else
 # define attribute(attrlist)
 #endif
 
-#if __GNUC__ >= 3
+#if GCC_VERSION(3,1)
 # define is_constant(c)             __builtin_constant_p (c)
 # define expect(expr,value)         __builtin_expect ((expr),(value))
 # define prefetch(addr,rw,locality) __builtin_prefetch (addr, rw, locality)
@@ -41,8 +43,17 @@
 # define noinline
 #endif
 
-#if __GNUC__ < 4 || (__GNUC__ == 4 || __GNUC_MINOR__ < 4)
-# define decltype(x) typeof(x)
+#define func_const attribute ((const))
+#define func_pure  attribute ((pure))
+#define func_hot   attribute ((hot))	// 4.x
+#define func_cold  attribute ((cold))	// 4.x
+
+#if GCC_VERSION(4,5)
+# define unreachable() __builtin_unreachable ()
+#else
+ // this seems to work fine, but gcc always emits a warning for it :/
+ static inline void unreachable () attribute ((noreturn));
+ static inline void unreachable () { }
 #endif
 
 // put into ifs if you are very sure that the expression
@@ -51,5 +62,8 @@
 #define expect_false(expr) expect ((expr) ? 1 : 0, 0)
 #define expect_true(expr)  expect ((expr) ? 1 : 0, 1)
 
+// try to tell the compiler that some condition is definitely true
+#define assume(cond) do { if (!(cond)) unreachable (); } while (0)
+
 #endif