nasm/include/compiler.h

/* SPDX-License-Identifier: BSD-2-Clause */
/* Copyright 2007-2025 The NASM Authors - All Rights Reserved */

/*
 * 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

#include "autoconf/attribute.h"

#ifdef HAVE_CONFIG_H
# include "config/config.h"
#else
# if defined(_MSC_VER) && (_MSC_VER >= 1310)
#  include "config/msvc.h"
# elif defined(__WATCOMC__)
#  include "config/watcom.h"
# else
#  include "config/unknown.h"
# endif
/* This unconditionally defines some macros we really want */
# include "config/unconfig.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 <string.h>
#include <limits.h>
#include <errno.h>

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

/*
 * This is impossible to do 100% accurately, because the actual type
 * of size_t may differ from its range.
 */
#ifdef _WIN32
# define PRIz "I"               /* Needed for msvcrt, not ucrt */
#elif defined(PRINTF_SUPPORTS_Z) || \
    (defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901L)
# define PRIz "z"
#elif SIZE_MAX == UINT_MAX
# define PRIz ""
#elif SIZE_MAX == ULONG_MAX
# define PRIz "l"
#elif SIZE_MAX == ULONGLONG_MAX
# define PRIz "ll"
#else
# error "Unable to determine printf format for size_t"
#endif
#define PRIzd PRIz "u"          /* size_t is always unsigned */
#define PRIzu PRIz "u"
#define PRIzu PRIz "u"
#define PRIzx PRIz "x"
#define PRIzX PRIz "X"

#ifdef HAVE_STDBIT_H

# include <stdbit.h>

# undef WORDS_LITTLEENDIAN
# undef WORDS_BIGENDIAN
# if __STDC_ENDIAN_NATIVE__ == __STDC_ENDIAN_LITTLE__
#  define WORDS_LITTLEENDIAN 1
# elif __STDC_ENDIAN_NATIVE__ == __STDC_ENDIAN_BIG__
#  define WORDS_BIGENDIAN 1
# endif

#else  /* No <stdbit.h> */

# 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

#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

/* C++ and C23 have bool, false, and true as proper keywords */
#if !defined(__cplusplus) && (__STDC_VERSION__ < 202311L)
# ifdef HAVE_STDBOOL_H
#  include <stdbool.h>
# elif defined(HAVE___BOOL)
   typedef _Bool bool;
#  define false 0
#  define true 1
# else
/* This is a bit dangerous, because casting to this ersatz bool
   will not produce the same result as the standard (bool) cast.
   Instead, use the explicit construct !!x instead of relying on
   implicit conversions or casts. */
typedef enum bool { false, true } bool;
# endif
#endif

/* Create a NULL pointer of the same type as the address of
   the argument, without actually evaluating said argument. */
#define nullas(p) (0 ? &(p) : NULL)

/* Convert an offsetted NULL pointer dereference to a size_t offset.
   Technically non-portable as taking the offset from a NULL pointer
   is undefined behavior, but... */
#define null_offset(p) ((size_t)((const char *)&(p) - (const char *)NULL))

/* 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) null_offset(((t *)NULL)->m)
#endif

/* If typeof is defined as a macro, assume we have typeof even if
   HAVE_TYPEOF is not declared (e.g. due to not using autoconf.) */
#ifdef typeof
# define HAVE_TYPEOF 1
#endif

/* This is like offsetof(), but takes an object rather than a type. */
#ifndef offsetin
# ifdef HAVE_TYPEOF
#  define offsetin(p,m) offsetof(typeof(p),m)
# else
#  define offsetin(p,m)	null_offset(nullas(p)->m)
# endif
#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

#ifndef HAVE_MEMPCPY
static inline void *mempcpy(void *dst, const void *src, size_t n)
{
    return (char *)memcpy(dst, src, n) + n;
}
#endif

#ifndef HAVE_MEMPSET
static inline void *mempset(void *dst, int c, size_t n)
{
    return (char *)memset(dst, c, n) + n;
}
#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.
 */
#ifdef HAVE___BUILTIN_EXPECT
# define likely(x)	__builtin_expect(!!(x), true)
# define unlikely(x)	__builtin_expect(!!(x), false)
#else
# define likely(x)	(!!(x))
# define unlikely(x)	(!!(x))
#endif

#ifdef HAVE___BUILTIN_PREFETCH
# define prefetch(x) __builtin_prefetch(x)
#else
# define prefetch(x) ((void)(x))
#endif

/*
 * Attributes
 */

#define safe_alloc     never_null     malloc_func
#define safe_alloc_ptr never_null_ptr malloc_func_ptr

#define safe_malloc(s)          safe_alloc     alloc_size_func1(s)
#define safe_malloc2(s1,s2)     safe_alloc     alloc_size_func2(s1,s2)
#define safe_realloc(s)         never_null     alloc_size_func1(s)
#define safe_malloc_ptr(s)      safe_alloc_ptr alloc_size_func1_ptr(s)
#define safe_malloc2_ptr(s1,s2) safe_alloc_ptr alloc_size_func2_ptr(s1,s2)
#define safe_realloc_ptr(s)     never_null_ptr alloc_size_func1_ptr(s)

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

/* Function priority: pure < reproducible < unsequenced < const */

#ifndef HAVE_FUNC_ATTRIBUTE_REPRODUCIBLE
# undef reproducible_func
# define reproducible_func pure_func
# undef reproducible_func_ptr
# define reproducible_func_ptr pure_func_ptr
#endif

#ifndef HAVE_FUNC_ATTRIBUTE_UNSEQUENCED
# undef unsequenced_func
# define unsequenced_func reproducible_func
# undef unsequenced_func_ptr
# define unsequenced_func_ptr reproducible_func_ptr
#endif

#ifndef HAVE_FUNC_ATTRIBUTE_CONST
# undef const_func
# define const_func reproducible_func
# undef const_func_ptr
# define const_func_ptr reproducible_func_ptr
#endif

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

/*
 * How to tell the compiler that a function takes a printf-like string
 */
#define printf_func(fmt, list)     format_func3(printf,fmt,list)
#define printf_func_ptr(fmt, list) format_func3_ptr(printf,fmt,list)
#define vprintf_func(fmt)          format_func3(printf,fmt,0)
#define vprintf_func_ptr(fmt)      format_func3_ptr(printf,fmt,0)

/* Determine probabilistically if something is a compile-time constant */
#ifdef HAVE___BUILTIN_CONSTANT_P
# if defined(__GNUC__) && (__GNUC__ >= 5)
#  define is_constant(x) __builtin_constant_p((x))
# else
#  define is_constant(x) false
# endif
#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

/*
 * If SIZE_MAX is not defined, rely on size_t being unsigned
 */
#ifndef SIZE_MAX
# define SIZE_MAX (((size_t)0) - 1)
#endif

/*
 * Current function name, if available, otherwise NULL
 */
#ifdef HAVE_FUNC_NAME
# define NASM_FUNC __func__
#else
# define NASM_FUNC NULL
#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

#ifndef unreachable              /* C23 defines as a macro in <stddef.h> */
# ifdef HAVE___BUILTIN_UNREACHABLE
#  define unreachable() __builtin_unreachable()
# else
#  define unreachable() do { abort(); } while(1)
# endif
#endif

/* This should be set from main() */
extern const char *_progname;

#endif	/* NASM_COMPILER_H */