Document Darwin-specific defaults.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@210958 91177308-0d34-0410-b5e6-96231b3b80d8

docs/UsersManual.rst

@@ -1298,7 +1298,7 @@ below. If multiple flags are present, the last one is used.
   doesn't contain any other data (e.g. description of local variables or
   function parameters).
 
-.. option:: -fstandalone-debug **-fno-standalone-debug**
+.. option:: -fstandalone-debug
 
   Clang supports a number of optimizations to reduce the size of debug
   information in the binary. They work based on the assumption that
@@ -1309,11 +1309,17 @@ below. If multiple flags are present, the last one is used.
   type info for a dynamic C++ class in the module that contains the
   vtable for the class.
 
-  The ``-fstandalone-debug`` option turns off these optimizations.
+  The **-fstandalone-debug** option turns off these optimizations.
   This is useful when working with 3rd-party libraries that don't come
   with debug information.  Note that Clang will never emit type
   information for types that are not referenced at all by the program.
 
+.. option:: -fno-standalone-debug
+
+   On Darwin **-fstandalone-debug** is enabled by default. The
+   **-fno-standalone-debug** option can be used to get to turn on the
+   vtable-based optimization described above.
+
 .. option:: -g
 
   Generate complete debug info.

docs/tools/clang.pod

@@ -324,8 +324,9 @@ C++ class in the module that contains the vtable for the class.
 
 The B<-fstandalone-debug> option turns off these optimizations.  This
 is useful when working with 3rd-party libraries that don't come with
-debug information.  Note that Clang will never emit type information
-for types that are not referenced at all by the program.
+debug information.  This is the default on Darwin.  Note that Clang
+will never emit type information for types that are not referenced at
+all by the program.
 
 =item B<-fexceptions>