[libcxx] Add OHOS support

[ldionne]

Summary

Add support for OpenHarmony OS (OHOS)

OpenHarmony is an open-source project incubated and operated by the OpenAtom Foundation. It targets IoT, and already used on production devices.

General OpenHarmony OS discussion on discourse thread: "Add support for OpenHarmony OS"

LLVM and clang parts of OHOS support: D138202, D145227

~~

Huawei RRI, OS Lab

[philnik]

As usual: Do you plan to get official support for OpenHarmony in libc++? If that's the case, please take a look at https://libcxx.llvm.org/AddingNewCIJobs.html#addingnewcijobs.

[Mordante]

Can you update the commit message to explain what OHOS is and provide a link to its homepage. That would be nice to have as a future reference.

[thesamesam]

The atomic changes look fine.

[kpdev42]

In D146804#4219942, @Mordante wrote:

Can you update the commit message to explain what OHOS is and provide a link to its homepage. That would be nice to have as a future reference.

Description is updated, please take a look

[kpdev42]

In D146804#4219175, @philnik wrote:

As usual: Do you plan to get official support for OpenHarmony in libc++? If that's the case, please take a look at https://libcxx.llvm.org/AddingNewCIJobs.html#addingnewcijobs.

Sure, we will try it, thank you

[Mordante]

In D146804#4248520, @kpdev42 wrote:

In D146804#4219175, @philnik wrote:

As usual: Do you plan to get official support for OpenHarmony in libc++? If that's the case, please take a look at https://libcxx.llvm.org/AddingNewCIJobs.html#addingnewcijobs.

Sure, we will try it, thank you

That would indeed be great to have.

LGTM, modulo one remark.

libcxx/include/__locale

46

At least I assume that was intended.

[Mordante]

Friendly ping? We'll be moving to GitHub soon can you update the patch if still interested into getting this in libc++?

[ldionne]

In D146804#4219175, @philnik wrote:

As usual: Do you plan to get official support for OpenHarmony in libc++? If that's the case, please take a look at https://libcxx.llvm.org/AddingNewCIJobs.html#addingnewcijobs.

+1 here, I don't think we can merge this unless we have a CI setup for it.

[kpdev42]

In D146804#4631923, @Mordante wrote:

Friendly ping? We'll be moving to GitHub soon can you update the patch if still interested into getting this in libc++?

Sure, I am interested in it ) But to setup the CI for it, I need to get a dedicated server and setup runner there. I think it may take some time, atm I have no experience with Buildkite.
Hope I will be able to make it happen in this month

[ldionne]

I am going to commandeer this patch and abandon it in order to clear up our Phabricator queue. If you would like to pursue this patch, please re-open it on GitHub (and if possible mention this review!) and we'll be happy to review it. Thanks!

libcxx/cmake/config-ix.cmake

if(WIN32 AND NOT MINGW)
   set(LIBCXX_HAS_SYSTEM_LIB NO)
   set(LIBCXX_HAS_ATOMIC_LIB NO)
 elseif(APPLE)
   check_library_exists(System write "" LIBCXX_HAS_SYSTEM_LIB)
   set(LIBCXX_HAS_PTHREAD_LIB NO)
   set(LIBCXX_HAS_M_LIB NO)
   set(LIBCXX_HAS_RT_LIB NO)
   set(LIBCXX_HAS_ATOMIC_LIB NO)
+elseif(OHOS)
+  set(LIBCXX_HAS_ATOMIC_LIB NO)
 elseif(FUCHSIA)
   set(LIBCXX_HAS_M_LIB NO)
   set(LIBCXX_HAS_PTHREAD_LIB NO)
   set(LIBCXX_HAS_RT_LIB NO)
   set(LIBCXX_HAS_SYSTEM_LIB NO)
   check_library_exists(atomic __atomic_fetch_add_8 "" LIBCXX_HAS_ATOMIC_LIB)
 else()
   check_library_exists(pthread pthread_create "" LIBCXX_HAS_PTHREAD_LIB)
   check_library_exists(m ccos "" LIBCXX_HAS_M_LIB)
   check_library_exists(rt clock_gettime "" LIBCXX_HAS_RT_LIB)
   set(LIBCXX_HAS_SYSTEM_LIB NO)
   check_library_exists(atomic __atomic_fetch_add_8 "" LIBCXX_HAS_ATOMIC_LIB)
 endif()

libcxx/include/__config

#    if defined(__FreeBSD__) ||                                                                                        \
         defined(__OpenBSD__) ||                                                                                        \
         defined(__NuttX__) ||                                                                                          \
         defined(__linux__) ||                                                                                          \
         defined(__GNU__) ||                                                                                            \
         defined(__APPLE__) ||                                                                                          \
         defined(__sun__) ||                                                                                            \
         defined(__MVS__) ||                                                                                            \
         defined(_AIX) ||                                                                                               \
-        defined(__EMSCRIPTEN__)
+        defined(__EMSCRIPTEN__) ||                                                                                     \
+        defined(__OHOS_FAMILY__)
 // clang-format on
 #      define _LIBCPP_HAS_THREAD_API_PTHREAD
 #    elif defined(__Fuchsia__)
 // TODO(44575): Switch to C11 thread API when possible.
 #      define _LIBCPP_HAS_THREAD_API_PTHREAD
 #    elif defined(_LIBCPP_WIN32API)
 #      define _LIBCPP_HAS_THREAD_API_WIN32
 #    else

 #  endif
 
 // Some systems do not provide gets() in their C library, for security reasons.
 #  if defined(_LIBCPP_MSVCRT) || (defined(__FreeBSD_version) && __FreeBSD_version >= 1300043) || defined(__OpenBSD__)
 #    define _LIBCPP_C_HAS_NO_GETS
 #  endif
 
 #  if defined(__BIONIC__) || defined(__NuttX__) || defined(__Fuchsia__) || defined(__wasi__) ||                        \
-      defined(_LIBCPP_HAS_MUSL_LIBC) || defined(__OpenBSD__)
+      defined(_LIBCPP_HAS_MUSL_LIBC) || defined(__OpenBSD__) || defined(__OHOS_FAMILY__)
 #    define _LIBCPP_PROVIDES_DEFAULT_RUNE_TABLE
 #  endif
 
 #  if __has_feature(cxx_atomic) || __has_extension(c_atomic) || __has_keyword(_Atomic)
 #    define _LIBCPP_HAS_C_ATOMIC_IMP
 #  elif defined(_LIBCPP_COMPILER_GCC)
 #    define _LIBCPP_HAS_GCC_ATOMIC_IMP
 #  endif

libcxx/include/__locale

 # include <__support/openbsd/xlocale.h>
 #elif (defined(__APPLE__) || defined(__FreeBSD__))
 # include <xlocale.h>
 #elif defined(__Fuchsia__)
 # include <__support/fuchsia/xlocale.h>
 #elif defined(__wasi__)
 // WASI libc uses musl's locales support.
 # include <__support/musl/xlocale.h>
+#elif defined(__OHOS_FAMILY__)
+// LiteOS libc uses musl's locales support.
+# include <__support/musl/xlocale.h>
 #elif defined(_LIBCPP_HAS_MUSL_LIBC)
 # include <__support/musl/xlocale.h>
 #endif
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
 #endif
 

libcxx/src/include/config_elast.h

 #elif defined(_NEWLIB_VERSION)
 #define _LIBCPP_ELAST __ELASTERROR
 #elif defined(__NuttX__)
 // No _LIBCPP_ELAST needed on NuttX
 #elif defined(__Fuchsia__)
 // No _LIBCPP_ELAST needed on Fuchsia
 #elif defined(__wasi__)
 // No _LIBCPP_ELAST needed on WASI
+#elif defined(__OHOS_FAMILY__)
+// No _LIBCPP_ELAST needed on OHOS
 #elif defined(__EMSCRIPTEN__)
 // No _LIBCPP_ELAST needed on Emscripten
 #elif defined(__linux__) || defined(_LIBCPP_HAS_MUSL_LIBC)
 #define _LIBCPP_ELAST 4095
 #elif defined(__APPLE__)
 // No _LIBCPP_ELAST needed on Apple
 #elif defined(__sun__)
 #define _LIBCPP_ELAST ESTALE