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Diffstat (limited to 'gnulib-m4/stdalign.m4')
-rw-r--r--gnulib-m4/stdalign.m4104
1 files changed, 91 insertions, 13 deletions
diff --git a/gnulib-m4/stdalign.m4 b/gnulib-m4/stdalign.m4
index 78577cb..324e91d 100644
--- a/gnulib-m4/stdalign.m4
+++ b/gnulib-m4/stdalign.m4
@@ -1,4 +1,4 @@
-# Check for stdalign.h that conforms to C11.
+# Check for alignas and alignof that conform to C23.
dnl Copyright 2011-2022 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
@@ -9,12 +9,18 @@ dnl with or without modifications, as long as this notice is preserved.
AC_DEFUN([gl_STDALIGN_H],
[
- AC_CACHE_CHECK([for working stdalign.h],
+ AC_CACHE_CHECK([for alignas and alignof],
[gl_cv_header_working_stdalign_h],
- [AC_COMPILE_IFELSE(
+ [gl_save_CFLAGS=$CFLAGS
+ for gl_working in "yes, keywords" "yes, <stdalign.h> macros"; do
+ AS_CASE([$gl_working],
+ [*stdalign.h*], [CFLAGS="$gl_save_CFLAGS -DINCLUDE_STDALIGN_H"])
+ AC_COMPILE_IFELSE(
[AC_LANG_PROGRAM(
[[#include <stdint.h>
- #include <stdalign.h>
+ #ifdef INCLUDE_STDALIGN_H
+ #include <stdalign.h>
+ #endif
#include <stddef.h>
/* Test that alignof yields a result consistent with offsetof.
@@ -30,7 +36,7 @@ AC_DEFUN([gl_STDALIGN_H],
char test_long[ao (long int) % _Alignof (long int) == 0 ? 1 : -1];
char test_alignof[alignof (double) == _Alignof (double) ? 1 : -1];
- /* Test _Alignas only on platforms where gnulib can help. */
+ /* Test alignas only on platforms where gnulib can help. */
#if \
((defined __cplusplus && 201103 <= __cplusplus) \
|| (__TINYC__ && defined __attribute__) \
@@ -45,12 +51,84 @@ AC_DEFUN([gl_STDALIGN_H],
? 1 : -1];
#endif
]])],
- [gl_cv_header_working_stdalign_h=yes],
- [gl_cv_header_working_stdalign_h=no])])
-
- if test $gl_cv_header_working_stdalign_h = yes; then
- GL_GENERATE_STDALIGN_H=false
- else
- GL_GENERATE_STDALIGN_H=true
- fi
+ [gl_cv_header_working_stdalign_h=$gl_working],
+ [gl_cv_header_working_stdalign_h=no])
+
+ CFLAGS=$gl_save_CFLAGS
+ test "$gl_cv_header_working_stdalign_h" != no && break
+ done])
+
+ GL_GENERATE_STDALIGN_H=false
+ AS_CASE([$gl_cv_header_working_stdalign_h],
+ [no],
+ [GL_GENERATE_STDALIGN_H=true],
+ [yes*keyword*],
+ [AC_DEFINE([HAVE_C_ALIGNASOF], [1],
+ [Define to 1 if the alignas and alignof keywords work.])])
+
+ AC_CHECK_HEADERS_ONCE([stdalign.h])
+
+ dnl The "zz" puts this toward config.h's end, to avoid potential
+ dnl collisions with other definitions.
+ AH_VERBATIM([zzalignas],
+[#if !defined HAVE_C_ALIGNASOF && __cplusplus < 201103 && !defined alignof
+# if HAVE_STDALIGN_H
+# include <stdalign.h>
+# else
+ /* Substitute. Keep consistent with gnulib/lib/stdalign.in.h. */
+# ifndef _GL_STDALIGN_H
+# define _GL_STDALIGN_H
+# undef _Alignas
+# undef _Alignof
+# if (!defined __STDC_VERSION__ || __STDC_VERSION__ < 201112 \
+ || (defined __GNUC__ && __GNUC__ < 4 + (__GNUC_MINOR__ < 9) \
+ && !defined __clang__) \
+ || (defined __clang__ && __clang_major__ < 8))
+# ifdef __cplusplus
+# if (201103 <= __cplusplus || defined _MSC_VER)
+# define _Alignof(type) alignof (type)
+# else
+ template <class __t> struct __alignof_helper { char __a; __t __b; };
+# define _Alignof(type) offsetof (__alignof_helper<type>, __b)
+# define _GL_STDALIGN_NEEDS_STDDEF 1
+# endif
+# else
+# define _Alignof(type) offsetof (struct { char __a; type __b; }, __b)
+# define _GL_STDALIGN_NEEDS_STDDEF 1
+# endif
+# endif
+# if ! (defined __cplusplus && (201103 <= __cplusplus || defined _MSC_VER))
+# define alignof _Alignof
+# endif
+# define __alignof_is_defined 1
+# if !defined __STDC_VERSION__ || __STDC_VERSION__ < 201112
+# if defined __cplusplus && (201103 <= __cplusplus || defined _MSC_VER)
+# define _Alignas(a) alignas (a)
+# elif (!defined __attribute__ \
+ && ((defined __APPLE__ && defined __MACH__ \
+ ? 4 < __GNUC__ + (1 <= __GNUC_MINOR__) \
+ : __GNUC__ && !defined __ibmxl__) \
+ || (4 <= __clang_major__) \
+ || (__ia64 && (61200 <= __HP_cc || 61200 <= __HP_aCC)) \
+ || __ICC || 0x590 <= __SUNPRO_C || 0x0600 <= __xlC__))
+# define _Alignas(a) __attribute__ ((__aligned__ (a)))
+# elif 1300 <= _MSC_VER
+# define _Alignas(a) __declspec (align (a))
+# endif
+# endif
+# if ((defined _Alignas \
+ && !(defined __cplusplus && (201103 <= __cplusplus || defined _MSC_VER))) \
+ || (defined __STDC_VERSION__ && 201112 <= __STDC_VERSION__))
+# define alignas _Alignas
+# endif
+# if (defined alignas \
+ || (defined __cplusplus && (201103 <= __cplusplus || defined _MSC_VER)))
+# define __alignas_is_defined 1
+# endif
+# if _GL_STDALIGN_NEEDS_STDDEF
+# include <stddef.h>
+# endif
+# endif /* _GL_STDALIGN_H */
+# endif
+#endif])
])