WinEH: Create an unwind help alloca for __CxxFrameHandler3 xdata tables

[oota-llvm.git] / docs / ExceptionHandling.rst

diff --git a/docs/ExceptionHandling.rst b/docs/ExceptionHandling.rst
index ee157d096a22e1f38110edc80e5c0a5a33c99d8e..21de19b0752c7bbf3983cb966a9a8c1ab7e86eea 100644 (file)
--- a/docs/ExceptionHandling.rst
+++ b/docs/ExceptionHandling.rst
@@ -539,6 +539,18 @@ In order to preserve the structure of the CFG, a call to '``llvm.eh.actions``'
 must be followed by an ':ref:`indirectbr <i_indirectbr>`' instruction that jumps
 to the result of the intrinsic call.
 
+``llvm.eh.unwindhelp``
+----------------------
+
+.. code-block:: llvm
+
+  void @llvm.eh.unwindhelp(i8*)
+
+This intrinsic designates the provided static alloca as the unwind help object.
+This object is used by Windows native exception handling on non-x86 platforms
+where xdata unwind information is used. It is typically an 8 byte chunk of
+memory treated as two 32-bit integers.
+
 
 SJLJ Intrinsics
 ---------------