Exception handling docs: Clarify how the llvm.eh.* intrinsics are used

The non-SJLJ and SJLJ intrinsics are generated by the frontend and
backend respectively.

Differential Revision: http://llvm-reviews.chandlerc.com/D3010

llvm-svn: 205017
diff --git a/llvm/docs/ExceptionHandling.rst b/llvm/docs/ExceptionHandling.rst
index 6a05eea..64edca7 100644
--- a/llvm/docs/ExceptionHandling.rst
+++ b/llvm/docs/ExceptionHandling.rst
@@ -327,10 +327,19 @@
 function.  This value can be used to compare against the result of
 ``landingpad`` instruction.  The single argument is a reference to a type info.
 
+Uses of this intrinsic are generated by the C++ front-end.
+
+SJLJ Intrinsics
+---------------
+
+The ``llvm.eh.sjlj`` intrinsics are used internally within LLVM's
+backend.  Uses of them are generated by the backend's
+``SjLjEHPrepare`` pass.
+
 .. _llvm.eh.sjlj.setjmp:
 
 ``llvm.eh.sjlj.setjmp``
------------------------
+~~~~~~~~~~~~~~~~~~~~~~~
 
 .. code-block:: llvm
 
@@ -352,7 +361,7 @@
 .. _llvm.eh.sjlj.longjmp:
 
 ``llvm.eh.sjlj.longjmp``
-------------------------
+~~~~~~~~~~~~~~~~~~~~~~~~
 
 .. code-block:: llvm
 
@@ -365,7 +374,7 @@
 destination address.
 
 ``llvm.eh.sjlj.lsda``
----------------------
+~~~~~~~~~~~~~~~~~~~~~
 
 .. code-block:: llvm
 
@@ -377,7 +386,7 @@
 function context for use by the runtime.
 
 ``llvm.eh.sjlj.callsite``
--------------------------
+~~~~~~~~~~~~~~~~~~~~~~~~~
 
 .. code-block:: llvm