[SystemZ][z/OS] Enable POSIX_l functions for z/OS

[muiez]

Summary

The aim of this patch is to enable POSIX _l functions for z/OS. In particular, the functions are provided with libc++ and this patch resorts to the fallback functions. Nonetheless, the functions are being added so the implementation of the ctype<> member functions can call them. The following changes were needed to allow for a successful build when using the libc++ library for z/OS.

[ldionne]

Please quit removing libc++ as a reviewer. There's a reason why we add that group of reviewers. You won't check this in without the approval of someone in the group anyway.

libcxx/include/wchar.h

173 ↗

(On Diff #301323)

Where are those defined for z/OS? I see definitions in src/solaris/support/mbsnrtowcs.inc and src/support/win32/support.cpp, but nothing that seems to be included when building for z/OS. Did I miss something?

[muiez]

Removed mbsnrtowcs and wcsnrtombs declarations from libcxx wchar.h. Adding those declarations to the system wchar.h instead.

[muiez]

libcxx/include/wchar.h

173 ↗

(On Diff #301323)

Please see updated revision. Removed this change and added the declarations to the system wchar.h instead.

[ldionne]

libcxx/include/support/ibm/xlocale.h

21

Wikipedia tells me that AIX 7.1 was released 10 years ago. Can we remove this AIX < 7.1 specific workaround?

libcxx/include/__config

 // Some systems do not provide gets() in their C library, for security reasons.
 #ifndef _LIBCPP_C_HAS_NO_GETS
 #  if defined(_LIBCPP_MSVCRT) || \
       (defined(__FreeBSD_version) && __FreeBSD_version >= 1300043)
 #    define _LIBCPP_C_HAS_NO_GETS
 #  endif
 #endif
 
-#if defined(__BIONIC__) || defined(__CloudABI__) ||                            \
-    defined(__Fuchsia__) || defined(__wasi__) || defined(_LIBCPP_HAS_MUSL_LIBC)
+#if defined(__BIONIC__) || defined(__CloudABI__) || \
+    defined(__Fuchsia__) || defined(__wasi__) || defined(_LIBCPP_HAS_MUSL_LIBC) || \
+    defined(__MVS__)
 #define _LIBCPP_PROVIDES_DEFAULT_RUNE_TABLE
 #endif
 
 // Thread-unsafe functions such as strtok() and localtime()
 // are not available.
 #ifdef __CloudABI__
 #define _LIBCPP_HAS_NO_THREAD_UNSAFE_C_FUNCTIONS
 #endif

libcxx/include/__locale

 #include <utility>
 #include <mutex>
 #include <cstdint>
 #include <cctype>
 #include <locale.h>
 #if defined(_LIBCPP_MSVCRT_LIKE)
 # include <cstring>
 # include <support/win32/locale_win32.h>
-#elif defined(_AIX)
+#elif defined(_AIX) || defined(__MVS__)
 # include <support/ibm/xlocale.h>
 #elif defined(__ANDROID__)
 # include <support/android/locale_bionic.h>
 #elif defined(__sun__)
 # include <xlocale.h>
 # include <support/solaris/xlocale.h>
 #elif defined(_NEWLIB_VERSION)
 # include <support/newlib/xlocale.h>

libcxx/include/support/ibm/xlocale.h

 // -*- C++ -*-
 //===--------------------- support/ibm/xlocale.h -------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef _LIBCPP_SUPPORT_IBM_XLOCALE_H
 #define _LIBCPP_SUPPORT_IBM_XLOCALE_H
 #include <support/ibm/locale_mgmt_aix.h>
 
-#if defined(_AIX)
 #include "cstdlib"
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
+#if defined(_AIX)
 #if !defined(_AIX71)
 // AIX 7.1 and higher has these definitions.  Definitions and stubs
 // are provied here as a temporary workaround on AIX 6.1.
 static inline
 int isalnum_l(int c, locale_t locale)
 {
   return __xisalnum(locale, c);
 }
 static inline

 static inline
 size_t wcsxfrm_l(wchar_t *__ws1, const wchar_t *__ws2, size_t __n,
     locale_t locale)
 {
   return __xwcsxfrm(locale, __ws1, __ws2, __n);
 }
 #endif // !defined(_AIX71)
 
-// strftime_l() is defined by POSIX. However, AIX 7.1 does not have it
-// implemented yet.
+// strftime_l() is defined by POSIX. However, AIX 7.1 and z/OS do not have it
+// implemented yet. z/OS retrieves it from the POSIX fallbacks.
 static inline
 size_t strftime_l(char *__s, size_t __size, const char *__fmt,
                   const struct tm *__tm, locale_t locale) {
   return __xstrftime(locale, __s, __size, __fmt, __tm);
 }
 
+#elif defined(__MVS__)
+#include <wctype.h>
+// POSIX routines
+#include <support/xlocale/__posix_l_fallback.h>
+#endif // defined(__MVS__)
+
 // The following are not POSIX routines.  These are quick-and-dirty hacks
 // to make things pretend to work
 static inline
 long long strtoll_l(const char *__nptr, char **__endptr,
     int __base, locale_t locale) {
   return strtoll(__nptr, __endptr, __base);
 }
 static inline
if ((str_size = vsnprintf(*strp, buff_size, fmt,  ap)) >= buff_size)
     str_size = vsnprintf(*strp, str_size + 1, fmt,  ap);
   }
   return str_size;
 }
 
 #ifdef __cplusplus
 }
 #endif
-#endif // defined(_AIX)
 #endif // _LIBCPP_SUPPORT_IBM_XLOCALE_H