/*
 * libc compiler.h
 *
 * Various compiler features
 */

#ifndef _LIBC_COMPILER_H
#define _LIBC_COMPILER_H

/* Specific calling conventions */
/* __cdecl is used when we want varadic and non-varadic functions to have
   the same binary calling convention. */
#ifdef __i386__
#ifdef __GNUC__
#define __cdecl __attribute__((cdecl, regparm(0)))
#else
/* Most other C compilers have __cdecl as a keyword */
#endif
#else
#define __cdecl /* Meaningless on non-i386 */
#endif

/* How to declare a function that *must* be inlined */
/* Use "extern inline" even in the gcc3+ case to avoid warnings in ctype.h */
#ifdef __GNUC__
#if __GNUC__ >= 3
#ifdef __GNUC_STDC_INLINE__
#define __must_inline extern __inline__ \
    __attribute__((__gnu_inline__, __always_inline__))
#else
#define __must_inline extern __inline__ __attribute__((__always_inline__))
#endif
#else
#define __must_inline extern __inline__
#endif
#else
#define __must_inline __inline /* Just hope this works... */
#define __inline inline
#endif

/* How to declare a function that does not return */
#ifdef __GNUC__
#define __noreturn void __attribute__((noreturn))
#else
#define __noreturn void
#endif

/* "const" function:

     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'.
*/
#ifdef __GNUC__
#define __constfunc __attribute__((const))
#else
#define __constfunc
#endif
#undef __attribute_const__
#define __attribute_const__ __constfunc

/* "pure" function:

     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.  These functions should be declared with the attribute
     `pure'.
*/
#ifdef __GNUC__
#define __purefunc __attribute__((pure))
#else
#define __purefunc
#endif
#undef __attribute_pure__
#define __attribute_pure__ __purefunc

/* Format attribute */
#ifdef __GNUC__
#define __formatfunc(t, f, a) __attribute__((format(t, f, a)))
#else
#define __formatfunc(t, f, a)
#endif

/* malloc() function (returns unaliased pointer) */
#if defined(__GNUC__) && (__GNUC__ >= 3)
#define __mallocfunc __attribute__((malloc))
#else
#define __mallocfunc
#endif

/* likely/unlikely */
#if defined(__GNUC__) && (__GNUC__ > 2 || (__GNUC__ == 2 && __GNUC_MINOR__ >= 95))
#define __likely(x)   __builtin_expect(!!(x), 1)
#define __unlikely(x) __builtin_expect(!!(x), 0)
#else
#define __likely(x)   (!!(x))
#define __unlikely(x) (!!(x))
#endif

#endif