Update users manual to indicate:
1) clang++ must be used when linking C++ programs using -fsanitize=undefined, and
2) MSan can't be combined with TSan or ASan.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@186711 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/docs/UsersManual.rst b/docs/UsersManual.rst
index 9037047..daa90b6 100644
--- a/docs/UsersManual.rst
+++ b/docs/UsersManual.rst
@@ -971,9 +971,17 @@
group.
The ``-fsanitize=`` argument must also be provided when linking, in
- order to link to the appropriate runtime library. It is not possible
- to combine the ``-fsanitize=address`` and ``-fsanitize=thread``
- checkers in the same program.
+ order to link to the appropriate runtime library. When using
+ ``-fsanitize=vptr`` (or a group that includes it, such as
+ ``-fsanitize=undefined``) with a C++ program, the link must be
+ performed by ``clang++``, not ``clang``, in order to link against the
+ C++-specific parts of the runtime library.
+
+ It is not possible to combine more than one of the ``-fsanitize=address``,
+ ``-fsanitize=thread``, and ``-fsanitize=memory`` checkers in the same
+ program. The ``-fsanitize=undefined`` checks can be combined with other
+ sanitizers.
+
**-f[no-]address-sanitizer**
Deprecated synonym for :ref:`-f[no-]sanitize=address
<opt_fsanitize_address>`.
