Comment & whitespace fixes

Author: vogelsgesang

libcxx/docs/DesignDocs/VisibilityMacros.rst

@@ -48,11 +48,11 @@ Visibility Macros
   This macro works by applying `[[gnu::gnu_inline]] inline` to the funciton
   in the header, thereby suppressing code generation while still allowing the
   compiler to use the function for optimization purposes.
-  During the build of libc++, we trigger code generation by not expanding the
-  macro to `_LIBCPP_EXPORTED_FROM_ABI`. Since the function is no longer marked
-  as `inline`, it will be emitted even if not called. (For this reason its
-  paramount to not define methods in the class definition, since those definitions
-  would be implicitly `inline`.)
+  During the build of libc++, we trigger code generation by expanding the
+  macro to `/*empty*/`. Since the function is no longer marked as `inline`,
+  it will be emitted even if not called. (For this reason its paramount to
+  not define methods in the class definition, since those definitions would
+  be implicitly `inline`.)
 
 **_LIBCPP_OVERRIDABLE_FUNC_VIS**
   Mark a symbol as being exported by the libc++ library, but allow it to be

libcxx/include/__exception/exception_ptr_glibcxx.ipp

@@ -13,10 +13,10 @@ namespace std {
 // it uses to implement std::exception_ptr (which it declares as an alias of
 // std::__exception_ptr::exception_ptr) is not directly exported to clients. So
 // we have little choice but to hijack std::__exception_ptr::exception_ptr's
-// (which fortunately has the same layout as our std::exception_ptr) copy
-// constructor, assignment operator and destructor (which are part of its
-// stable ABI), and its rethrow_exception(std::__exception_ptr::exception_ptr)
-// function.
+// _M_addref and _M_release (which are part of its ABI), and its
+// rethrow_exception(std::__exception_ptr::exception_ptr) function. Fortunately,
+// glibcxx's exception_ptr has the same layout as our exception_ptr and we can
+// reinterpret_cast between the two.
 namespace __exception_ptr {
 
 struct exception_ptr {