--- /dev/null
+#ifndef _LWK_COMPILER_H
+#define _LWK_COMPILER_H
+
+#ifndef __ASSEMBLY__
+
+#ifdef __CHECKER__
+# define __user __attribute__((noderef, address_space(1)))
+# define __kernel /* default address space */
+# define __safe __attribute__((safe))
+# define __force __attribute__((force))
+# define __nocast __attribute__((nocast))
+# define __iomem __attribute__((noderef, address_space(2)))
+# define __acquires(x) __attribute__((context(0,1)))
+# define __releases(x) __attribute__((context(1,0)))
+# define __acquire(x) __context__(1)
+# define __release(x) __context__(-1)
+# define __cond_lock(x) ((x) ? ({ __context__(1); 1; }) : 0)
+extern void __chk_user_ptr(void __user *);
+extern void __chk_io_ptr(void __iomem *);
+#else
+# define __user
+# define __kernel
+# define __safe
+# define __force
+# define __nocast
+# define __iomem
+# define __chk_user_ptr(x) (void)0
+# define __chk_io_ptr(x) (void)0
+# define __builtin_warning(x, y...) (1)
+# define __acquires(x)
+# define __releases(x)
+# define __acquire(x) (void)0
+# define __release(x) (void)0
+# define __cond_lock(x) (x)
+#endif
+
+#ifdef __KERNEL__
+
+#if __GNUC__ > 4
+#error no compiler-gcc.h file for this gcc version
+#elif __GNUC__ == 4
+# include <lwk/compiler-gcc4.h>
+#else
+# error Sorry, your compiler is too old/not recognized.
+#endif
+
+/*
+ * Generic compiler-dependent macros required for kernel
+ * build go below this comment. Actual compiler/compiler version
+ * specific implementations come from the above header files
+ */
+
+#define likely(x) __builtin_expect(!!(x), 1)
+#define unlikely(x) __builtin_expect(!!(x), 0)
+
+/* Optimization barrier */
+#ifndef barrier
+# define barrier() __memory_barrier()
+#endif
+
+#ifndef RELOC_HIDE
+# define RELOC_HIDE(ptr, off) \
+ ({ unsigned long __ptr; \
+ __ptr = (unsigned long) (ptr); \
+ (typeof(ptr)) (__ptr + (off)); })
+#endif
+
+#endif /* __KERNEL__ */
+
+#endif /* __ASSEMBLY__ */
+
+#ifdef __KERNEL__
+/*
+ * Allow us to mark functions as 'deprecated' and have gcc emit a nice
+ * warning for each use, in hopes of speeding the functions removal.
+ * Usage is:
+ * int __deprecated foo(void)
+ */
+#ifndef __deprecated
+# define __deprecated /* unimplemented */
+#endif
+
+#ifndef __must_check
+#define __must_check
+#endif
+
+/*
+ * Allow us to avoid 'defined but not used' warnings on functions and data,
+ * as well as force them to be emitted to the assembly file.
+ *
+ * As of gcc 3.3, static functions that are not marked with attribute((used))
+ * may be elided from the assembly file. As of gcc 3.3, static data not so
+ * marked will not be elided, but this may change in a future gcc version.
+ *
+ * In prior versions of gcc, such functions and data would be emitted, but
+ * would be warned about except with attribute((unused)).
+ */
+#ifndef __attribute_used__
+# define __attribute_used__ /* unimplemented */
+#endif
+
+/*
+ * From the GCC manual:
+ *
+ * Many functions have no effects except the return value and their
+ * return value depends only on the parameters and/or global
+ * variables. Such a function can be subject to common subexpression
+ * elimination and loop optimization just as an arithmetic operator
+ * would be.
+ * [...]
+ */
+#ifndef __attribute_pure__
+# define __attribute_pure__ /* unimplemented */
+#endif
+
+#ifndef noinline
+#define noinline
+#endif
+
+#ifndef __always_inline
+#define __always_inline inline
+#endif
+
+#endif /* __KERNEL__ */
+
+/*
+ * From the GCC manual:
+ *
+ * Many functions do not examine any values except their arguments,
+ * and have no effects except the return value. Basically this is
+ * just slightly more strict class than the `pure' attribute above,
+ * since function is not allowed to read global memory.
+ *
+ * Note that a function that has pointer arguments and examines the
+ * data pointed to must _not_ be declared `const'. Likewise, a
+ * function that calls a non-`const' function usually must not be
+ * `const'. It does not make sense for a `const' function to return
+ * `void'.
+ */
+#ifndef __attribute_const__
+# define __attribute_const__ /* unimplemented */
+#endif
+
+#endif /* _LWK_COMPILER_H */
