[libcxx] Make LIBCXX_HERMETIC_STATIC_LIBRARY apply to libc++experimental too

[mstorsjo]

Summary

This avoids dllexports in that library.

[ldionne]

libcxx/src/CMakeLists.txt

337

Shouldn't we always add these flags to cxx_experimental, i.e. not only when LIBCXX_HERMETIC_STATIC_LIBRARY=ON?

[mstorsjo]

libcxx/src/CMakeLists.txt

337

Well this is how it’s done for the regular static library above, lines 295-302.

[mstorsjo]

libcxx/src/CMakeLists.txt

337

The only place CXX_STATIC_LIBRARY_FLAGS is set is on line 300 above, where -fvisibility-global-new-delete-hidden is added to the variable. But I guess that we don't need to set that at all for libc++experimental, as that library doesn't provide any new/delete operators?

I can rerun this patch in CI with the target_compile_options(cxx_experimental PRIVATE ${CXX_STATIC_LIBRARY_FLAGS}) line omitted, as it's not needed for the case I'm fixing here anyway.

[mstorsjo]

Removed the setting of CXX_STATIC_LIBRARY_FLAGS for cxx_+experimental, as it probably isn't needed. Will push later when CI has passed.

[phosek]

LGTM

libcxx/src/CMakeLists.txt

if (LIBCXX_ENABLE_EXPERIMENTAL_LIBRARY)
   endif()
 
   set_target_properties(cxx_experimental
     PROPERTIES
       COMPILE_FLAGS "${LIBCXX_COMPILE_FLAGS}"
       OUTPUT_NAME   "c++experimental"
   )
   cxx_add_common_build_flags(cxx_experimental)
+
+  if (LIBCXX_HERMETIC_STATIC_LIBRARY)
+    # _LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS can be defined in __config_site
+    # too. Define it in the same way here, to avoid redefinition conflicts.
+    target_compile_definitions(cxx_experimental PRIVATE _LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS=)
+  endif()
 endif()
 
 
 if (LIBCXX_BUILD_EXTERNAL_THREAD_LIBRARY)
   set(LIBCXX_EXTERNAL_THREADING_SUPPORT_SOURCES
       "${CMAKE_CURRENT_SOURCE_DIR}/../test/support/external_threads.cpp")
 
   if (LIBCXX_ENABLE_SHARED)

libcxx/test/libcxx/vendor/clang-cl/experimental-lib-exports.sh.cpp

+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// REQUIRES: msvc && c++experimental
+
+// This file checks that the built experimental static library doesn't contain dllexport
+// directives in clang-cl builds.
+
+// RUN: llvm-readobj --coff-directives "%{lib}/libc++experimental.lib" | not grep -i "export:" > /dev/null

libcxx/test/libcxx/vendor/mingw/experimental-lib-exports.sh.cpp

+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// REQUIRES: target={{.+}}-windows-gnu && c++experimental
+
+// This file checks that the built experimental static library doesn't contain dllexport
+// directives in MinGW builds.
+
+// RUN: llvm-readobj --coff-directives "%{lib}/libc++experimental.a" | not grep -i "export:" > /dev/null