[libc++] Make _LIBCPP_TYPE_VIS export members

Summary:
Most classes annotated with _LIBCPP_TYPE_VIS need to have at least some
of their members exported, otherwise we have a lot of link errors when
linking against a libc++ built with hidden visibility. This also makes
_LIBCPP_TYPE_VIS be consistent across platforms, since on Windows it
already exports members.

With this change made, any template methods of a class marked
_LIBCPP_TYPE_VIS will also get default visibility when instantiatied,
which is not desirable for clients of libc++ headers who wish to control
their visibility; this is the same issue as PR30642. Annotate all
problematic methods with an explicit visibility specifier to avoid this.

The problematic methods were found by running bad-visibility-finder [1]
against the libc++ headers after making the _LIBCPP_TYPE_VIS change. The
small methods were marked for inlining; the larger ones hidden.

[1] https://github.com/smeenai/bad-visibility-finder

Reviewers: mclow.lists, EricWF

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D25208

llvm-svn: 296732

Author: smeenai

libcxx/docs/DesignDocs/VisibilityMacros.rst

@@ -47,18 +47,17 @@ Visibility Macros
   A synonym for `_LIBCPP_INLINE_VISIBILITY`
 
 **_LIBCPP_TYPE_VIS**
+  Mark a type's typeinfo, vtable and members as having default visibility.
+  This attribute cannot be used on class templates.
+
+**_LIBCPP_TEMPLATE_VIS**
   Mark a type's typeinfo and vtable as having default visibility.
-  `_LIBCPP_TYPE_VIS`. This macro has no effect on the visibility of the
-  type's member functions. This attribute cannot be used on class templates.
+  This macro has no effect on the visibility of the type's member functions.
 
   **GCC Behavior**: GCC does not support Clang's `type_visibility(...)`
   attribute. With GCC the `visibility(...)` attribute is used and member
   functions are affected.
 
-**_LIBCPP_TEMPLATE_VIS**
-  The same as `_LIBCPP_TYPE_VIS` except that it may be applied to class
-  templates.
-
   **Windows Behavior**: DLLs do not support dllimport/export on class templates.
   The macro has an empty definition on this platform.
 

libcxx/include/__config

@@ -628,18 +628,22 @@ namespace std {
 
 #ifndef _LIBCPP_TYPE_VIS
 #  if !defined(_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS)
-#    if __has_attribute(__type_visibility__)
-#      define _LIBCPP_TYPE_VIS __attribute__ ((__type_visibility__("default")))
-#    else
-#      define _LIBCPP_TYPE_VIS __attribute__ ((__visibility__("default")))
-#    endif
+#    define _LIBCPP_TYPE_VIS __attribute__ ((__visibility__("default")))
 #  else
 #    define _LIBCPP_TYPE_VIS
 #  endif
 #endif
 
 #ifndef _LIBCPP_TEMPLATE_VIS
-# define _LIBCPP_TEMPLATE_VIS _LIBCPP_TYPE_VIS
+#  if !defined(_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS)
+#    if __has_attribute(__type_visibility__)
+#      define _LIBCPP_TEMPLATE_VIS __attribute__ ((__type_visibility__("default")))
+#    else
+#      define _LIBCPP_TEMPLATE_VIS __attribute__ ((__visibility__("default")))
+#    endif
+#  else
+#    define _LIBCPP_TEMPLATE_VIS
+#  endif
 #endif
 
 #ifndef _LIBCPP_FUNC_VIS_ONLY

libcxx/include/__locale

@@ -92,13 +92,16 @@ public:
 
     const locale& operator=(const locale&)  _NOEXCEPT;
 
-    template <class _Facet> locale combine(const locale&) const;
+    template <class _Facet>
+      _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
+      locale combine(const locale&) const;
 
     // locale operations:
     string name() const;
     bool operator==(const locale&) const;
     bool operator!=(const locale& __y) const {return !(*this == __y);}
     template <class _CharT, class _Traits, class _Allocator>
+      _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
       bool operator()(const basic_string<_CharT, _Traits, _Allocator>&,
                       const basic_string<_CharT, _Traits, _Allocator>&) const;
 

libcxx/include/__mutex_base

@@ -316,20 +316,24 @@ public:
 
     void wait(unique_lock<mutex>& __lk) _NOEXCEPT;
     template <class _Predicate>
+        _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
         void wait(unique_lock<mutex>& __lk, _Predicate __pred);
 
     template <class _Clock, class _Duration>
+        _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
         cv_status
         wait_until(unique_lock<mutex>& __lk,
                    const chrono::time_point<_Clock, _Duration>& __t);
 
     template <class _Clock, class _Duration, class _Predicate>
+        _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
         bool
         wait_until(unique_lock<mutex>& __lk,
                    const chrono::time_point<_Clock, _Duration>& __t,
                    _Predicate __pred);
 
     template <class _Rep, class _Period>
+        _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
         cv_status
         wait_for(unique_lock<mutex>& __lk,
                  const chrono::duration<_Rep, _Period>& __d);

libcxx/include/condition_variable

@@ -133,12 +133,14 @@ public:
     void notify_all() _NOEXCEPT;
 
     template <class _Lock>
+        _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
         void wait(_Lock& __lock);
     template <class _Lock, class _Predicate>
         _LIBCPP_INLINE_VISIBILITY
         void wait(_Lock& __lock, _Predicate __pred);
 
     template <class _Lock, class _Clock, class _Duration>
+        _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
         cv_status
         wait_until(_Lock& __lock,
                    const chrono::time_point<_Clock, _Duration>& __t);

libcxx/include/future

@@ -582,6 +582,7 @@ public:
         _LIBCPP_INLINE_VISIBILITY
         wait_for(const chrono::duration<_Rep, _Period>& __rel_time) const;
     template <class _Clock, class _Duration>
+        _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
         future_status
         wait_until(const chrono::time_point<_Clock, _Duration>& __abs_time) const;
 
@@ -1674,6 +1675,7 @@ class _LIBCPP_TYPE_VIS promise<void>
 public:
     promise();
     template <class _Allocator>
+        _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
         promise(allocator_arg_t, const _Allocator& __a);
 #ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
     _LIBCPP_INLINE_VISIBILITY

libcxx/include/mutex

@@ -248,6 +248,7 @@ public:
         bool try_lock_for(const chrono::duration<_Rep, _Period>& __d)
             {return try_lock_until(chrono::steady_clock::now() + __d);}
     template <class _Clock, class _Duration>
+        _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
         bool try_lock_until(const chrono::time_point<_Clock, _Duration>& __t);
     void unlock() _NOEXCEPT;
 };
@@ -291,6 +292,7 @@ public:
         bool try_lock_for(const chrono::duration<_Rep, _Period>& __d)
             {return try_lock_until(chrono::steady_clock::now() + __d);}
     template <class _Clock, class _Duration>
+        _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
         bool try_lock_until(const chrono::time_point<_Clock, _Duration>& __t);
     void unlock() _NOEXCEPT;
 };

libcxx/include/shared_mutex

@@ -220,6 +220,7 @@ public:
             return try_lock_until(chrono::steady_clock::now() + __rel_time);
         }
     template <class _Clock, class _Duration>
+        _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
         bool
         try_lock_until(const chrono::time_point<_Clock, _Duration>& __abs_time);
     void unlock();
@@ -235,6 +236,7 @@ public:
             return try_lock_shared_until(chrono::steady_clock::now() + __rel_time);
         }
     template <class _Clock, class _Duration>
+        _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
         bool
         try_lock_shared_until(const chrono::time_point<_Clock, _Duration>& __abs_time);
     void unlock_shared();

libcxx/include/thread

@@ -298,9 +298,12 @@ public:
                    !is_same<typename decay<_Fp>::type, thread>::value
               >::type
              >
+        _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
         explicit thread(_Fp&& __f, _Args&&... __args);
 #else  // _LIBCPP_HAS_NO_VARIADICS
-    template <class _Fp> explicit thread(_Fp __f);
+    template <class _Fp>
+    _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS
+    explicit thread(_Fp __f);
 #endif
     ~thread();