include/compiler.h

/* ----------------------------------------------------------------------- *
 *   
 *   Copyright 2007-2018 The NASM Authors - All Rights Reserved
 *   See the file AUTHORS included with the NASM distribution for
 *   the specific copyright holders.
 *
 *   Redistribution and use in source and binary forms, with or without
 *   modification, are permitted provided that the following
 *   conditions are met:
 *
 *   * Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *   * Redistributions in binary form must reproduce the above
 *     copyright notice, this list of conditions and the following
 *     disclaimer in the documentation and/or other materials provided
 *     with the distribution.
 *     
 *     THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
 *     CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
 *     INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 *     MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 *     DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 *     CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 *     SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 *     NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 *     LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 *     HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 *     CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
 *     OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
 *     EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * ----------------------------------------------------------------------- */

/*
 * compiler.h
 *
 * Compiler-specific macros for NASM.  Feel free to add support for
 * other compilers in here.
 *
 * This header file should be included before any other header.
 */

#ifndef NASM_COMPILER_H
#define NASM_COMPILER_H 1

/*
 * At least DJGPP and Cygwin have broken header files if __STRICT_ANSI__
 * is defined.
 */
#ifdef __GNUC__
# undef __STRICT_ANSI__
#endif

/* On Microsoft platforms we support multibyte character sets in filenames */
#define _MBCS 1

#ifdef HAVE_CONFIG_H
# include "config/config.h"
#elif defined(_MSC_VER) && (_MSC_VER >= 1310)
# include "config/msvc.h"
#elif defined(__WATCOMC__)
# include "config/watcom.h"
#else
# include "config/unknown.h"
#endif /* Configuration file */

/* This is required to get the standard <inttypes.h> macros when compiling
   with a C++ compiler.  This must be defined *before* <inttypes.h> is
   included, directly or indirectly. */
#define __STDC_CONSTANT_MACROS	1
#define __STDC_LIMIT_MACROS	1
#define __STDC_FORMAT_MACROS	1

#ifdef HAVE_INTTYPES_H
# include <inttypes.h>
#else
# include "nasmint.h"
#endif

#include <assert.h>
#include <stddef.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <limits.h>

#ifdef HAVE_SYS_TYPES_H
# include <sys/types.h>
#endif

#ifdef HAVE_ENDIAN_H
# include <endian.h>
#elif defined(HAVE_SYS_ENDIAN_H)
# include <sys/endian.h>
#elif defined(HAVE_MACHINE_ENDIAN_H)
# include <machine/endian.h>
#endif

/*
 * If we have BYTE_ORDER defined, or the compiler provides
 * __BIG_ENDIAN__ or __LITTLE_ENDIAN__, trust it over what autoconf
 * came up with, especially since autoconf obviously can't figure
 * things out for a universal compiler.
 */
#if defined(__BIG_ENDIAN__) && !defined(__LITTLE_ENDIAN__)
# undef WORDS_LITTLEENDIAN
# undef WORDS_BIGENDIAN
# define WORDS_BIGENDIAN 1
#elif defined(__LITTLE_ENDIAN__) && !defined(__BIG_ENDIAN__)
# undef WORDS_LITTLEENDIAN
# undef WORDS_BIGENDIAN
# define WORDS_LITTLEENDIAN 1
#elif defined(BYTE_ORDER) && defined(LITTLE_ENDIAN) && defined(BIG_ENDIAN)
# undef WORDS_LITTLEENDIAN
# undef WORDS_BIGENDIAN
# if BYTE_ORDER == LITTLE_ENDIAN
#  define WORDS_LITTLEENDIAN 1
# elif BYTE_ORDER == BIG_ENDIAN
#  define WORDS_BIGENDIAN 1
# endif
#endif

/*
 * Define this to 1 for faster performance if this is a littleendian
 * platform *and* it can do arbitrary unaligned memory references.  It
 * is safe to leave it defined to 0 even if that is true.
 */
#if defined(__386__) || defined(__i386__) || defined(__x86_64__) \
    || defined(_M_IX86) || defined(_M_X64)
# define X86_MEMORY 1
# undef WORDS_BIGENDIAN
# undef WORDS_LITTLEENDIAN
# define WORDS_LITTLEENDIAN 1
#else
# define X86_MEMORY 0
#endif

/* Some versions of MSVC have these only with underscores in front */
#ifndef HAVE_SNPRINTF
# ifdef HAVE__SNPRINTF
#  define snprintf _snprintf
# else
int snprintf(char *, size_t, const char *, ...);
# endif
#endif

#ifndef HAVE_VSNPRINTF
# ifdef HAVE__VSNPRINTF
#  define vsnprintf _vsnprintf
# else
int vsnprintf(char *, size_t, const char *, va_list);
# endif
#endif

#if !defined(HAVE_STRLCPY) || !HAVE_DECL_STRLCPY
size_t strlcpy(char *, const char *, size_t);
#endif

#if !defined(HAVE_STRCHRNUL) || !HAVE_DECL_STRCHRNUL
char *strrchrnul(const char *, int);
#endif

#ifndef __cplusplus		/* C++ has false, true, bool as keywords */
# ifdef HAVE_STDBOOL_H
#  include <stdbool.h>
# elif defined(HAVE__BOOL)
#  typedef _Bool bool
#  define false 0
#  define true 1
# else
/* This is sort of dangerous, since casts will behave different than
   casting to the standard boolean type.  Always use !!, not (bool). */
typedef enum bool { false, true } bool;
# endif
#endif

/* Provide a substitute for offsetof() if we don't have one.  This
   variant works on most (but not *all*) systems... */
#ifndef offsetof
# define offsetof(t,m) ((size_t)&(((t *)0)->m))
#endif

/* This is like offsetof(), but takes an object rather than a type.
   Ironically enough this is actually guaranteed to be portable,
   as far as I know... */
#ifndef offsetin
# define offsetin(p,m)	((const char *)&((p).m) - (const char *)&(p))
#endif

/* The container_of construct: if p is a pointer to member m of
   container class c, then return a pointer to the container of which
   *p is a member. */
#ifndef container_of
# define container_of(p, c, m) ((c *)((char *)(p) - offsetof(c,m)))
#endif

/* Some misguided platforms hide the defs for these */
#if defined(HAVE_STRCASECMP) && !HAVE_DECL_STRCASECMP
int strcasecmp(const char *, const char *);
#endif

#if defined(HAVE_STRICMP) && !HAVE_DECL_STRICMP
int stricmp(const char *, const char *);
#endif

#if defined(HAVE_STRNCASECMP) && !HAVE_DECL_STRNCASECMP
int strncasecmp(const char *, const char *, size_t);
#endif

#if defined(HAVE_STRNICMP) && !HAVE_DECL_STRNICMP
int strnicmp(const char *, const char *, size_t);
#endif

#if defined(HAVE_STRSEP) && !HAVE_DECL_STRSEP
char *strsep(char **, const char *);
#endif

#if !HAVE_DECL_STRNLEN
size_t strnlen(const char *s, size_t maxlen);
#endif

/*
 * Hack to support external-linkage inline functions
 */
#ifndef HAVE_STDC_INLINE
# ifdef __GNUC__
#  ifdef __GNUC_STDC_INLINE__
#   define HAVE_STDC_INLINE
#  else
#   define HAVE_GNU_INLINE
#  endif
# elif defined(__GNUC_GNU_INLINE__)
/* Some other compiler implementing only GNU inline semantics? */
#   define HAVE_GNU_INLINE
# elif defined(__STDC_VERSION__)
#  if __STDC_VERSION__ >= 199901L
#   define HAVE_STDC_INLINE
#  endif
# endif
#endif

#ifdef HAVE_STDC_INLINE
# define extern_inline inline
#elif defined(HAVE_GNU_INLINE)
# define extern_inline extern inline
# define inline_prototypes
#else
# define inline_prototypes
#endif

/*
 * Hints to the compiler that a particular branch of code is more or
 * less likely to be taken.
 */
#if HAVE___BUILTIN_EXPECT
# define likely(x)	__builtin_expect(!!(x), 1)
# define unlikely(x)	__builtin_expect(!!(x), 0)
#else
# define likely(x)	(!!(x))
# define unlikely(x)	(!!(x))
#endif

/*
 * Hints about malloc-like functions that never return NULL
 */
#ifdef HAVE_FUNC_ATTRIBUTE_RETURNS_NONNULL
# define never_null __attribute__((returns_nonnull))
#else
# define never_null
#endif

#ifdef HAVE_FUNC_ATTRIBUTE_MALLOC
# define safe_alloc never_null __attribute__((malloc))
#else
# define safe_alloc never_null
#endif

#ifdef HAVE_FUNC_ATTRIBUTE_ALLOC_SIZE
# define safe_malloc(s) safe_alloc __attribute__((alloc_size(s)))
# define safe_malloc2(s1,s2) safe_alloc __attribute__((alloc_size(s1,s2)))
# define safe_realloc(s) never_null __attribute__((alloc_size(s)))
#else
# define safe_malloc(s) safe_alloc
# define safe_malloc2(s1,s2) safe_alloc
# define safe_realloc(s) never_null
#endif

#ifdef HAVE_FUNC_ATTRIBUTE_SENTINEL
# define end_with_null __attribute__((sentinel))
#else
# define end_with_null
#endif

/*
 * How to tell the compiler that a function doesn't return
 */
#ifdef HAVE_STDNORETURN_H
# include <stdnoreturn.h>
# define no_return noreturn void
#elif defined(HAVE_FUNC_ATTRIBUTE_NORETURN)
# define no_return void __attribute__((noreturn))
#elif defined(_MSC_VER)
# define no_return __declspec(noreturn) void
#else
# define no_return void
#endif

/*
 * How to tell the compiler that a function is unlikely to be executed.
 * This differs from unlikely() in that it is applied to a function call,
 * not a boolean condition.
 */
#ifdef HAVE_FUNC_ATTRIBUTE_COLD
# define unlikely_func __attribute__((cold))
#else
# define unlikely_func
#endif

/*
 * A fatal function is both unlikely and no_return
 */
#define fatal_func no_return unlikely_func

/*
 * How to tell the compiler that a function takes a printf-like string
 */
#ifdef HAVE_FUNC_ATTRIBUTE_FORMAT
# define printf_func(fmt, list) __attribute__((format(printf, fmt, list)))
#else
# define printf_func(fmt, list)
#endif

/*
 * How to tell the compiler that a function is pure arithmetic
 */
#ifdef HAVE_FUNC_ATTRIBUTE_CONST
# define const_func __attribute__((const))
#else
# define const_func
#endif

/*
 * This function has no side effects, but depends on its arguments,
 * memory pointed to by its arguments, or global variables.
 * NOTE: functions that return a value by modifying memory pointed to
 * by a pointer argument are *NOT* considered pure.
 */
#ifdef HAVE_FUNC_ATTRIBUTE_PURE
# define pure_func __attribute__((pure))
#else
# define pure_func
#endif

/* Determine probabilistically if something is a compile-time constant */
#ifdef HAVE___BUILTIN_CONSTANT_P
# define is_constant(x) __builtin_constant_p((x))
#else
# define is_constant(x) false
#endif

/*
 * If we can guarantee that a particular expression is constant, use it,
 * otherwise use a different version.
 */
#if defined(__GNUC__) && (__GNUC__ >= 3)
# define not_pedantic_start                             \
    _Pragma("GCC diagnostic push")                      \
    _Pragma("GCC diagnostic ignored \"-Wpedantic\"")
# define not_pedantic_end                       \
    _Pragma("GCC diagnostic pop")
#else
# define not_pedantic_start
# define not_pedantic_end
#endif

#ifdef HAVE___BUILTIN_CHOOSE_EXPR
# define if_constant(x,y) __builtin_choose_expr(is_constant(x),(x),(y))
#else
# define if_constant(x,y) (y)
#endif

/*
 * The autoconf documentation states:
 *
 * `va_copy'
 *    The C99 standard provides `va_copy' for copying `va_list'
 *    variables.  It may be available in older environments too, though
 *    possibly as `__va_copy' (e.g., `gcc' in strict pre-C99 mode).
 *    These can be tested with `#ifdef'.  A fallback to `memcpy (&dst,
 *    &src, sizeof (va_list))' gives maximum portability.
 */
#ifndef va_copy
# ifdef __va_copy
#  define va_copy(dst,src) __va_copy(dst,src)
# else
#  define va_copy(dst,src) memcpy(&(dst),&(src),sizeof(va_list))
# endif
#endif

/* Watcom doesn't handle switch statements with 64-bit types, hack around it */
#ifdef __WATCOMC__
# define BOGUS_CASE 0x76543210

static inline unsigned int watcom_switch_hack(uint64_t x)
{
    if (x > (uint64_t)UINT_MAX)
        return BOGUS_CASE;
    else
        return (unsigned int)x;
}

# define switch(x) switch(sizeof(x) > sizeof(unsigned int) \
                          ? watcom_switch_hack(x) : (unsigned int)(x))

/* This is to make sure BOGUS_CASE doesn't conflict with anything real... */
# define default case BOGUS_CASE: default
#endif

#endif	/* NASM_COMPILER_H */