mirror of
https://github.com/netwide-assembler/nasm.git
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44ec97993a
C23 defines unreachable() as a macro in <stddef.h>. For earlier versions of gcc, __builtin_unreachable() is possible. Signed-off-by: H. Peter Anvin (Intel) <hpa@zytor.com>
481 lines
13 KiB
C
481 lines
13 KiB
C
/* SPDX-License-Identifier: BSD-2-Clause */
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/* Copyright 2007-2025 The NASM Authors - All Rights Reserved */
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/*
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* compiler.h
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*
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* Compiler-specific macros for NASM. Feel free to add support for
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* other compilers in here.
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*
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* This header file should be included before any other header.
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*/
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#ifndef NASM_COMPILER_H
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#define NASM_COMPILER_H 1
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/*
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* At least DJGPP and Cygwin have broken header files if __STRICT_ANSI__
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* is defined.
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*/
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#ifdef __GNUC__
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# undef __STRICT_ANSI__
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#endif
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/* On Microsoft platforms we support multibyte character sets in filenames */
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#define _MBCS 1
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#include "autoconf/attribute.h"
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#ifdef HAVE_CONFIG_H
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# include "config/config.h"
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#else
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# if defined(_MSC_VER) && (_MSC_VER >= 1310)
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# include "config/msvc.h"
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# elif defined(__WATCOMC__)
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# include "config/watcom.h"
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# else
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# include "config/unknown.h"
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# endif
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/* This unconditionally defines some macros we really want */
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# include "config/unconfig.h"
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#endif /* Configuration file */
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/* This is required to get the standard <inttypes.h> macros when compiling
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with a C++ compiler. This must be defined *before* <inttypes.h> is
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included, directly or indirectly. */
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#define __STDC_CONSTANT_MACROS 1
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#define __STDC_LIMIT_MACROS 1
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#define __STDC_FORMAT_MACROS 1
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#ifdef HAVE_INTTYPES_H
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# include <inttypes.h>
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#else
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# include "nasmint.h"
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#endif
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#include <assert.h>
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#include <stddef.h>
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#include <stdarg.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <limits.h>
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#include <errno.h>
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#ifdef HAVE_STRINGS_H
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# include <strings.h>
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#endif
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#ifdef HAVE_SYS_TYPES_H
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# include <sys/types.h>
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#endif
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/*
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* This is impossible to do 100% accurately, because the actual type
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* of size_t may differ from its range.
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*/
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#ifdef _WIN32
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# define PRIz "I" /* Needed for msvcrt, not ucrt */
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#elif defined(PRINTF_SUPPORTS_Z) || \
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(defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901L)
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# define PRIz "z"
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#elif SIZE_MAX == UINT_MAX
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# define PRIz ""
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#elif SIZE_MAX == ULONG_MAX
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# define PRIz "l"
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#elif SIZE_MAX == ULONGLONG_MAX
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# define PRIz "ll"
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#else
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# error "Unable to determine printf format for size_t"
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#endif
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#define PRIzd PRIz "u" /* size_t is always unsigned */
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#define PRIzu PRIz "u"
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#define PRIzu PRIz "u"
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#define PRIzx PRIz "x"
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#define PRIzX PRIz "X"
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#ifdef HAVE_STDBIT_H
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# include <stdbit.h>
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# undef WORDS_LITTLEENDIAN
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# undef WORDS_BIGENDIAN
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# if __STDC_ENDIAN_NATIVE__ == __STDC_ENDIAN_LITTLE__
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# define WORDS_LITTLEENDIAN 1
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# elif __STDC_ENDIAN_NATIVE__ == __STDC_ENDIAN_BIG__
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# define WORDS_BIGENDIAN 1
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# endif
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#else /* No <stdbit.h> */
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# ifdef HAVE_ENDIAN_H
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# include <endian.h>
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# elif defined(HAVE_SYS_ENDIAN_H)
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# include <sys/endian.h>
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# elif defined(HAVE_MACHINE_ENDIAN_H)
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# include <machine/endian.h>
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# endif
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/*
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* If we have BYTE_ORDER defined, or the compiler provides
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* __BIG_ENDIAN__ or __LITTLE_ENDIAN__, trust it over what autoconf
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* came up with, especially since autoconf obviously can't figure
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* things out for a universal compiler.
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*/
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# if defined(__BIG_ENDIAN__) && !defined(__LITTLE_ENDIAN__)
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# undef WORDS_LITTLEENDIAN
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# undef WORDS_BIGENDIAN
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# define WORDS_BIGENDIAN 1
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# elif defined(__LITTLE_ENDIAN__) && !defined(__BIG_ENDIAN__)
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# undef WORDS_LITTLEENDIAN
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# undef WORDS_BIGENDIAN
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# define WORDS_LITTLEENDIAN 1
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# elif defined(BYTE_ORDER) && defined(LITTLE_ENDIAN) && defined(BIG_ENDIAN)
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# undef WORDS_LITTLEENDIAN
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# undef WORDS_BIGENDIAN
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# if BYTE_ORDER == LITTLE_ENDIAN
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# define WORDS_LITTLEENDIAN 1
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# elif BYTE_ORDER == BIG_ENDIAN
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# define WORDS_BIGENDIAN 1
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# endif
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# endif
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#endif
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/*
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* Define this to 1 for faster performance if this is a littleendian
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* platform *and* it can do arbitrary unaligned memory references. It
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* is safe to leave it defined to 0 even if that is true.
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*/
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#if defined(__386__) || defined(__i386__) || defined(__x86_64__) \
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|| defined(_M_IX86) || defined(_M_X64)
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# define X86_MEMORY 1
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# undef WORDS_BIGENDIAN
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# undef WORDS_LITTLEENDIAN
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# define WORDS_LITTLEENDIAN 1
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#else
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# define X86_MEMORY 0
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#endif
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/* Some versions of MSVC have these only with underscores in front */
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#ifndef HAVE_SNPRINTF
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# ifdef HAVE__SNPRINTF
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# define snprintf _snprintf
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# else
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int snprintf(char *, size_t, const char *, ...);
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# endif
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#endif
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#ifndef HAVE_VSNPRINTF
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# ifdef HAVE__VSNPRINTF
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# define vsnprintf _vsnprintf
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# else
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int vsnprintf(char *, size_t, const char *, va_list);
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# endif
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#endif
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#if !defined(HAVE_STRLCPY) || !HAVE_DECL_STRLCPY
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size_t strlcpy(char *, const char *, size_t);
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#endif
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#if !defined(HAVE_STRCHRNUL) || !HAVE_DECL_STRCHRNUL
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char * pure_func strrchrnul(const char *, int);
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#endif
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/* C++ and C23 have bool, false, and true as proper keywords */
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#if !defined(__cplusplus) && (__STDC_VERSION__ < 202311L)
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# ifdef HAVE_STDBOOL_H
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# include <stdbool.h>
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# elif defined(HAVE___BOOL)
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typedef _Bool bool;
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# define false 0
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# define true 1
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# else
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/* This is a bit dangerous, because casting to this ersatz bool
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will not produce the same result as the standard (bool) cast.
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Instead, use the explicit construct !!x instead of relying on
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implicit conversions or casts. */
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typedef enum bool { false, true } bool;
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# endif
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#endif
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/* Create a NULL pointer of the same type as the address of
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the argument, without actually evaluating said argument. */
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#define nullas(p) (0 ? &(p) : NULL)
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/* Convert an offsetted NULL pointer dereference to a size_t offset.
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Technically non-portable as taking the offset from a NULL pointer
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is undefined behavior, but... */
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#define null_offset(p) ((size_t)((const char *)&(p) - (const char *)NULL))
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/* Provide a substitute for offsetof() if we don't have one. This
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variant works on most (but not *all*) systems... */
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#ifndef offsetof
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# define offsetof(t,m) null_offset(((t *)NULL)->m)
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#endif
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/* If typeof is defined as a macro, assume we have typeof even if
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HAVE_TYPEOF is not declared (e.g. due to not using autoconf.) */
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#ifdef typeof
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# define HAVE_TYPEOF 1
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#endif
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/* This is like offsetof(), but takes an object rather than a type. */
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#ifndef offsetin
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# ifdef HAVE_TYPEOF
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# define offsetin(p,m) offsetof(typeof(p),m)
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# else
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# define offsetin(p,m) null_offset(nullas(p)->m)
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# endif
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#endif
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/* The container_of construct: if p is a pointer to member m of
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container class c, then return a pointer to the container of which
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*p is a member. */
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#ifndef container_of
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# define container_of(p, c, m) ((c *)((char *)(p) - offsetof(c,m)))
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#endif
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/* Some misguided platforms hide the defs for these */
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#if defined(HAVE_STRCASECMP) && !HAVE_DECL_STRCASECMP
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int strcasecmp(const char *, const char *);
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#endif
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#if defined(HAVE_STRICMP) && !HAVE_DECL_STRICMP
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int stricmp(const char *, const char *);
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#endif
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#if defined(HAVE_STRNCASECMP) && !HAVE_DECL_STRNCASECMP
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int strncasecmp(const char *, const char *, size_t);
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#endif
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#if defined(HAVE_STRNICMP) && !HAVE_DECL_STRNICMP
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int strnicmp(const char *, const char *, size_t);
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#endif
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#if defined(HAVE_STRSEP) && !HAVE_DECL_STRSEP
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char *strsep(char **, const char *);
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#endif
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#if !HAVE_DECL_STRNLEN
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size_t strnlen(const char *s, size_t maxlen);
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#endif
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#ifndef HAVE_MEMPCPY
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static inline void *mempcpy(void *dst, const void *src, size_t n)
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{
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return (char *)memcpy(dst, src, n) + n;
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}
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#endif
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#ifndef HAVE_MEMPSET
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static inline void *mempset(void *dst, int c, size_t n)
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{
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return (char *)memset(dst, c, n) + n;
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}
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#endif
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/*
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* Hack to support external-linkage inline functions
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*/
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#ifndef HAVE_STDC_INLINE
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# ifdef __GNUC__
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# ifdef __GNUC_STDC_INLINE__
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# define HAVE_STDC_INLINE
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# else
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# define HAVE_GNU_INLINE
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# endif
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# elif defined(__GNUC_GNU_INLINE__)
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/* Some other compiler implementing only GNU inline semantics? */
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# define HAVE_GNU_INLINE
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# elif defined(__STDC_VERSION__)
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# if __STDC_VERSION__ >= 199901L
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# define HAVE_STDC_INLINE
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# endif
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# endif
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#endif
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#ifdef HAVE_STDC_INLINE
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# define extern_inline inline
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#elif defined(HAVE_GNU_INLINE)
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# define extern_inline extern inline
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# define inline_prototypes
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#else
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# define inline_prototypes
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#endif
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/*
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* Hints to the compiler that a particular branch of code is more or
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* less likely to be taken.
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*/
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#ifdef HAVE___BUILTIN_EXPECT
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# define likely(x) __builtin_expect(!!(x), true)
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# define unlikely(x) __builtin_expect(!!(x), false)
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#else
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# define likely(x) (!!(x))
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# define unlikely(x) (!!(x))
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#endif
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#ifdef HAVE___BUILTIN_PREFETCH
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# define prefetch(x) __builtin_prefetch(x)
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#else
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# define prefetch(x) ((void)(x))
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#endif
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/*
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* Attributes
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*/
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#define safe_alloc never_null malloc_func
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#define safe_alloc_ptr never_null_ptr malloc_func_ptr
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#define safe_malloc(s) safe_alloc alloc_size_func1(s)
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#define safe_malloc2(s1,s2) safe_alloc alloc_size_func2(s1,s2)
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#define safe_realloc(s) never_null alloc_size_func1(s)
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#define safe_malloc_ptr(s) safe_alloc_ptr alloc_size_func1_ptr(s)
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#define safe_malloc2_ptr(s1,s2) safe_alloc_ptr alloc_size_func2_ptr(s1,s2)
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#define safe_realloc_ptr(s) never_null_ptr alloc_size_func1_ptr(s)
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/*
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* How to tell the compiler that a function doesn't return
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*/
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#ifdef HAVE_STDNORETURN_H
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# include <stdnoreturn.h>
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# define no_return noreturn
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#elif defined(_MSC_VER)
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# define no_return __declspec(noreturn)
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#else
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# define no_return noreturn_func
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#endif
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/* Function priority: pure < reproducible < unsequenced < const */
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#ifndef HAVE_FUNC_ATTRIBUTE_REPRODUCIBLE
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# undef reproducible_func
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# define reproducible_func pure_func
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# undef reproducible_func_ptr
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# define reproducible_func_ptr pure_func_ptr
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#endif
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#ifndef HAVE_FUNC_ATTRIBUTE_UNSEQUENCED
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# undef unsequenced_func
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# define unsequenced_func reproducible_func
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# undef unsequenced_func_ptr
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# define unsequenced_func_ptr reproducible_func_ptr
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#endif
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#ifndef HAVE_FUNC_ATTRIBUTE_CONST
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# undef const_func
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# define const_func reproducible_func
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# undef const_func_ptr
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# define const_func_ptr reproducible_func_ptr
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#endif
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/*
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* A fatal function is both unlikely and no_return
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*/
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#define fatal_func no_return unlikely_func void
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#define static_fatal_func no_return unlikely_func static void
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/*
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* How to tell the compiler that a function takes a printf-like string
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*/
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#define printf_func(fmt, list) format_func3(printf,fmt,list)
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#define printf_func_ptr(fmt, list) format_func3_ptr(printf,fmt,list)
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#define vprintf_func(fmt) format_func3(printf,fmt,0)
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#define vprintf_func_ptr(fmt) format_func3_ptr(printf,fmt,0)
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/* Determine probabilistically if something is a compile-time constant */
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#ifdef HAVE___BUILTIN_CONSTANT_P
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# if defined(__GNUC__) && (__GNUC__ >= 5)
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# define is_constant(x) __builtin_constant_p((x))
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# else
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# define is_constant(x) false
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# endif
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#else
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# define is_constant(x) false
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#endif
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/*
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* If we can guarantee that a particular expression is constant, use it,
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* otherwise use a different version.
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*/
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#if defined(__GNUC__) && (__GNUC__ >= 3)
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# define not_pedantic_start \
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_Pragma("GCC diagnostic push") \
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_Pragma("GCC diagnostic ignored \"-Wpedantic\"")
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# define not_pedantic_end \
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_Pragma("GCC diagnostic pop")
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#else
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# define not_pedantic_start
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# define not_pedantic_end
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#endif
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#ifdef HAVE___BUILTIN_CHOOSE_EXPR
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# define if_constant(x,y) __builtin_choose_expr(is_constant(x),(x),(y))
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#else
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# define if_constant(x,y) (y)
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#endif
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/*
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* The autoconf documentation states:
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*
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* `va_copy'
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* The C99 standard provides `va_copy' for copying `va_list'
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* variables. It may be available in older environments too, though
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* possibly as `__va_copy' (e.g., `gcc' in strict pre-C99 mode).
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* These can be tested with `#ifdef'. A fallback to `memcpy (&dst,
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* &src, sizeof (va_list))' gives maximum portability.
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*/
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#ifndef va_copy
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# ifdef __va_copy
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# define va_copy(dst,src) __va_copy(dst,src)
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# else
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# define va_copy(dst,src) memcpy(&(dst),&(src),sizeof(va_list))
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# endif
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#endif
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/*
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* If SIZE_MAX is not defined, rely on size_t being unsigned
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*/
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#ifndef SIZE_MAX
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# define SIZE_MAX (((size_t)0) - 1)
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#endif
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/*
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* Current function name, if available, otherwise NULL
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*/
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#ifdef HAVE_FUNC_NAME
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# define NASM_FUNC __func__
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#else
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# define NASM_FUNC NULL
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#endif
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/* Watcom doesn't handle switch statements with 64-bit types, hack around it */
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#ifdef __WATCOMC__
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# define BOGUS_CASE 0x76543210
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static inline unsigned int watcom_switch_hack(uint64_t x)
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{
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if (x > (uint64_t)UINT_MAX)
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return BOGUS_CASE;
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else
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return (unsigned int)x;
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}
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# define switch(x) switch(sizeof(x) > sizeof(unsigned int) \
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? watcom_switch_hack(x) : (unsigned int)(x))
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/* This is to make sure BOGUS_CASE doesn't conflict with anything real... */
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# define default case BOGUS_CASE: default
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#endif
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#ifndef unreachable /* C23 defines as a macro in <stddef.h> */
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# ifdef HAVE___BUILTIN_UNREACHABLE
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# define unreachable() __builtin_unreachable()
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# else
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# define unreachable() do { abort(); } while(1)
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# endif
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#endif
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#endif /* NASM_COMPILER_H */
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