[llvm] r231181 - Document the LLVM "thunk" attribute added back in r226708

[Reid Kleckner]

Author: rnk
Date: Tue Mar  3 18:08:56 2015
New Revision: 231181

URL: http://llvm.org/viewvc/llvm-project?rev=231181&view=rev
Log:
Document the LLVM "thunk" attribute added back in r226708

Modified:
    llvm/trunk/docs/LangRef.rst

Modified: llvm/trunk/docs/LangRef.rst
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/docs/LangRef.rst?rev=231181&r1=231180&r2=231181&view=diff
==============================================================================
--- llvm/trunk/docs/LangRef.rst (original)
+++ llvm/trunk/docs/LangRef.rst Tue Mar  3 18:08:56 2015
@@ -1369,6 +1369,11 @@ example:
     If a function that has an ``sspstrong`` attribute is inlined into a
     function that doesn't have an ``sspstrong`` attribute, then the
     resulting function will have an ``sspstrong`` attribute.
+``"thunk"``
+    This attribute indicates that the function will delegate to some other
+    function with a tail call. The prototype of a thunk should not be used for
+    optimization purposes. The caller is expected to cast the thunk prototype to
+    match the thunk target prototype.
 ``uwtable``
     This attribute indicates that the ABI being targeted requires that
     an unwind table entry be produce for this function even if we can