[libc++] Add _LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS

It's useful to be able to disable visibility annotations entirely; for
example, if we're building libc++ static to include in another library,
and we don't want any libc++ functions getting exported out of that
library. This is a generalization of _LIBCPP_DISABLE_DLL_IMPORT_EXPORT.

Differential Revision: https://reviews.llvm.org/D26934

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@288690 91177308-0d34-0410-b5e6-96231b3b80d8

CMakeLists.txt

@@ -518,7 +518,7 @@ config_define_if(LIBCXX_HAS_MUSL_LIBC _LIBCPP_HAS_MUSL_LIBC)
 # static library only we modify the headers to disable DLL import/export.
 if (DEFINED WIN32 AND LIBCXX_ENABLE_STATIC AND NOT LIBCXX_ENABLE_SHARED)
   message(STATUS "Generating custom __config for non-DLL Windows build")
-  config_define(ON _LIBCPP_DISABLE_DLL_IMPORT_EXPORT)
+  config_define(ON _LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS)
 endif()
 
 if (LIBCXX_NEEDS_SITE_CONFIG)

docs/UsingLibcxx.rst

@@ -149,3 +149,9 @@ thread safety annotations.
   This macro is used to enable -Wthread-safety annotations on libc++'s
   ``std::mutex`` and ``std::lock_guard``. By default these annotations are
   disabled and must be manually enabled by the user.
+
+**_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS**:
+  This macro is used to disable all visibility annotations inside libc++.
+  Defining this macro and then building libc++ with hidden visibility gives a
+  build of libc++ which does not export any symbols, which can be useful when
+  building statically for inclusion into another library.

include/__config

@@ -510,7 +510,7 @@ namespace std {
 
 
 #ifdef _WIN32
-#if defined(_LIBCPP_DISABLE_DLL_IMPORT_EXPORT)
+#if defined(_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS)
 # define _LIBCPP_DLL_VIS
 # define _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS
 # define _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS
@@ -546,18 +546,30 @@ namespace std {
 #endif // _WIN32
 
 #ifndef _LIBCPP_HIDDEN
+#if !defined(_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS)
 #define _LIBCPP_HIDDEN __attribute__ ((__visibility__("hidden")))
+#else
+#define _LIBCPP_HIDDEN
+#endif
 #endif
 
 #ifndef _LIBCPP_FUNC_VIS
+#if !defined(_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS)
 #define _LIBCPP_FUNC_VIS __attribute__ ((__visibility__("default")))
+#else
+#define _LIBCPP_FUNC_VIS
+#endif
 #endif
 
 #ifndef _LIBCPP_TYPE_VIS
-#  if __has_attribute(__type_visibility__)
+#  if !defined(_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS)
-#    define _LIBCPP_TYPE_VIS __attribute__ ((__type_visibility__("default")))
+#    if __has_attribute(__type_visibility__)
+#      define _LIBCPP_TYPE_VIS __attribute__ ((__type_visibility__("default")))
+#    else
+#      define _LIBCPP_TYPE_VIS __attribute__ ((__visibility__("default")))
+#    endif
 #  else
-#    define _LIBCPP_TYPE_VIS __attribute__ ((__visibility__("default")))
+#    define _LIBCPP_TYPE_VIS
 #  endif
 #endif
 
@@ -574,11 +586,15 @@ namespace std {
 #endif
 
 #ifndef _LIBCPP_EXCEPTION_ABI
+#if !defined(_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS)
 #define _LIBCPP_EXCEPTION_ABI __attribute__ ((__visibility__("default")))
+#else
+#define _LIBCPP_EXCEPTION_ABI
+#endif
 #endif
 
 #ifndef _LIBCPP_ENUM_VIS
-#  if __has_attribute(__type_visibility__)
+#  if !defined(_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS) && __has_attribute(__type_visibility__)
 #    define _LIBCPP_ENUM_VIS __attribute__ ((__type_visibility__("default")))
 #  else
 #    define _LIBCPP_ENUM_VIS
@@ -586,7 +602,7 @@ namespace std {
 #endif
 
 #ifndef _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS
-#  if __has_attribute(__type_visibility__)
+#  if !defined(_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS) && __has_attribute(__type_visibility__)
 #    define _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS __attribute__ ((__type_visibility__("default")))
 #  else
 #    define _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS
@@ -598,15 +614,27 @@ namespace std {
 #endif
 
 #ifndef _LIBCPP_INLINE_VISIBILITY
+#if !defined(_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS)
 #define _LIBCPP_INLINE_VISIBILITY __attribute__ ((__visibility__("hidden"), __always_inline__))
+#else
+#define _LIBCPP_INLINE_VISIBILITY __attribute__ ((__always_inline__))
+#endif
 #endif
 
 #ifndef _LIBCPP_ALWAYS_INLINE
+#if !defined(_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS)
 #define _LIBCPP_ALWAYS_INLINE  __attribute__ ((__visibility__("hidden"), __always_inline__))
+#else
+#define _LIBCPP_ALWAYS_INLINE  __attribute__ ((__always_inline__))
+#endif
 #endif
 
 #ifndef _LIBCPP_EXTERN_TEMPLATE_INLINE_VISIBILITY
-# define _LIBCPP_EXTERN_TEMPLATE_INLINE_VISIBILITY __attribute__((__visibility__("default"), __always_inline__))
+# if !defined(_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS)
+#  define _LIBCPP_EXTERN_TEMPLATE_INLINE_VISIBILITY __attribute__((__visibility__("default"), __always_inline__))
+# else
+#  define _LIBCPP_EXTERN_TEMPLATE_INLINE_VISIBILITY __attribute__((__always_inline__))
+# endif
 #endif
 
 #ifndef _LIBCPP_PREFERRED_OVERLOAD

include/__config_site.in

@@ -21,6 +21,6 @@
 #cmakedefine _LIBCPP_HAS_MUSL_LIBC
 #cmakedefine _LIBCPP_HAS_THREAD_API_PTHREAD
 #cmakedefine _LIBCPP_HAS_THREAD_API_EXTERNAL
-#cmakedefine _LIBCPP_DISABLE_DLL_IMPORT_EXPORT
+#cmakedefine _LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS
 
 #endif // _LIBCPP_CONFIG_SITE