1 files changed, 38 insertions, 0 deletions
diff --git a/docs/LangRef.html b/docs/LangRef.html
index cac8fc79da..457a56ab0c 100644
--- a/docs/LangRef.html
+++ b/docs/LangRef.html
@@ -65,6 +65,7 @@
       <li><a href="#globalconstants">Global Variable and Function Addresses</a></li>
       <li><a href="#undefvalues">Undefined Values</a></li>
       <li><a href="#constantexprs">Constant Expressions</a></li>
+      <li><a href="#metadata">Embedded Metadata</a></li>
     </ol>
   </li>
   <li><a href="#othervalues">Other Values</a>
@@ -1847,6 +1848,14 @@ constants and smaller complex constants.</p>
   large arrays) and is always exactly equivalent to using explicit zero
   initializers.
   </dd>
+
+  <dt><b>Metadata node</b></dt>
+
+  <dd>A metadata node is a structure-like constant with the type of an empty
+  struct.  For example: "<tt>{ } !{ i32 0, { } !"test" }</tt>". Unlike other
+  constants that are meant to be interpreted as part of the instruction stream,
+  metadata is a place to attach additional information such as debug info.
+  </dd>
 </dl>
 
 </div>
@@ -2015,6 +2024,35 @@ following is the syntax for constant expressions:</p>
 </dl>
 </div>
 
+<!-- ======================================================================= -->
+<div class="doc_subsection"><a name="metadata">Embedded Metadata</a>
+</div>
+
+<div class="doc_text">
+
+<p>Embedded metadata provides a way to attach arbitrary data to the
+instruction stream without affecting the behaviour of the program.  There are
+two metadata primitives, strings and nodes. All metadata has the type of an
+empty struct and is identified in syntax by a preceding exclamation point
+('<tt>!</tt>').
+</p>
+
+<p>A metadata string is a string surrounded by double quotes.  It can contain
+any character by escaping non-printable characters with "\xx" where "xx" is
+the two digit hex code.  For example: "<tt>!"test\00"</tt>".
+</p>
+
+<p>Metadata nodes are represented with notation similar to structure constants
+(a comma separated list of elements, surrounded by braces and preceeded by an
+exclamation point).  For example: "<tt>!{ { } !"test\00", i32 10}</tt>".
+</p>
+
+<p>Optimizations may rely on metadata to provide additional information about
+the program that isn't available in the instructions, or that isn't easily
+computable. Similarly, the code generator may expect a certain metadata format
+to be used to express debugging information.</p>
+</div>
+
 <!-- *********************************************************************** -->
 <div class="doc_section"> <a name="othervalues">Other Values</a> </div>
 <!-- *********************************************************************** -->