Add clang crash diagnostic info and associated flags to Clang user manual.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@151184 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/docs/UsersManual.html b/docs/UsersManual.html
index 779e402..4b8f5af 100644
--- a/docs/UsersManual.html
+++ b/docs/UsersManual.html
@@ -30,6 +30,8 @@
   <ul>
   <li><a href="#cl_diagnostics">Options to Control Error and Warning
       Messages</a></li>
+  <li><a href="#cl_crash_diagnostics">Options to Control Clang Crash
+      Diagnostics</a></li>
   </ul>
 </li>
 <li><a href="#general_features">Language and Target-Independent Features</a>
@@ -196,6 +198,26 @@
 
 <p><b>-ftemplate-backtrace-limit=123</b>: Only emit up to 123 template instantiation notes within the template instantiation backtrace for a single warning or error. The default is 10, and the limit can be disabled with -ftemplate-backtrace-limit=0.</p>
 
+<!-- = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = -->
+<h3 id="cl_crash_diagnostics">Options to Control Clang Crash Diagnostics</h3>
+<!-- = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = -->
+
+<p>As unbelievable as it may sound, Clang does crash from time to time.  
+Generally, this only occurs to those living on the 
+<a href="http://llvm.org/releases/download.html#svn">bleeding edge</a>.  Clang
+goes to great lengths to assist you in filing a bug report.  Specifically, Clang
+generates preprocessed source file(s) and associated run script(s) upon a
+crash.  These files should be attached to a bug report to ease reproducibility
+of the failure.  Below are the command line options to control the crash
+diagnostics.
+</p>
+
+<p><b>-fno-crash-diagnostics</b>: Disable auto-generation of preprocessed 
+source files during a clang crash.</p>
+
+<p>The -fno-crash-diagnostics flag can be helpful for speeding the process of
+generating a delta reduced test case.</p>
+
 <!-- ================================================= -->
 <h4 id="cl_diag_formatting">Formatting of Diagnostics</h4>
 <!-- ================================================= -->