[libcxx-commits] [PATCH] D158216: [libc++] Assume that __BYTE_ORDER__ is always present

[Louis Dionne via Phabricator via libcxx-commits]

ldionne accepted this revision.
ldionne added a comment.
This revision is now accepted and ready to land.

LGTM with suggestion applied.



================
Comment at: libcxx/include/__config:428
 
-#  ifdef __LITTLE_ENDIAN__
-#    if __LITTLE_ENDIAN__
-#      define _LIBCPP_LITTLE_ENDIAN
-#    endif // __LITTLE_ENDIAN__
-#  endif   // __LITTLE_ENDIAN__
-
-#  ifdef __BIG_ENDIAN__
-#    if __BIG_ENDIAN__
-#      define _LIBCPP_BIG_ENDIAN
-#    endif // __BIG_ENDIAN__
-#  endif   // __BIG_ENDIAN__
-
-#  ifdef __BYTE_ORDER__
-#    if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
-#      define _LIBCPP_LITTLE_ENDIAN
-#    elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
-#      define _LIBCPP_BIG_ENDIAN
-#    endif // __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
-#  endif   // __BYTE_ORDER__
-
-#  ifdef __FreeBSD__
-#    include <osreldate.h>
-#    include <sys/endian.h>
-#    if _BYTE_ORDER == _LITTLE_ENDIAN
-#      define _LIBCPP_LITTLE_ENDIAN
-#    else // _BYTE_ORDER == _LITTLE_ENDIAN
-#      define _LIBCPP_BIG_ENDIAN
-#    endif // _BYTE_ORDER == _LITTLE_ENDIAN
-#  endif   // __FreeBSD__
-
-#  if defined(__NetBSD__) || defined(__OpenBSD__)
-#    include <sys/endian.h>
-#    if _BYTE_ORDER == _LITTLE_ENDIAN
-#      define _LIBCPP_LITTLE_ENDIAN
-#    else // _BYTE_ORDER == _LITTLE_ENDIAN
-#      define _LIBCPP_BIG_ENDIAN
-#    endif // _BYTE_ORDER == _LITTLE_ENDIAN
-#  endif   // defined(__NetBSD__) || defined(__OpenBSD__)
+#  if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+#    define _LIBCPP_LITTLE_ENDIAN
----------------
Can we do something like

```
#ifndef __BYTE_ORDER__
#error "Your compiler doesn't seem to define __BYTE_ORDER__, which is required by libc++ to know the endianness of your target platform
#endif
```

This will catch any failure to satisfy our assumptions here.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D158216/new/

https://reviews.llvm.org/D158216