Add Foreach Loop

[oota-llvm.git] / docs / TableGenFundamentals.html

diff --git a/docs/TableGenFundamentals.html b/docs/TableGenFundamentals.html
index 6db1827b3be6cae930a50940b9aa4f6a90691f02..45baf198454e62dbf63607da6b265aff3c66b6cc 100644 (file)
--- a/docs/TableGenFundamentals.html
+++ b/docs/TableGenFundamentals.html
@@ -37,6 +37,7 @@
     <ol>
       <li><a href="#include">File inclusion</a></li>
       <li><a href="#globallet">'let' expressions</a></li>
+      <li><a href="#foreach">'foreach' blocks</a></li>
     </ol></li>
   </ol></li>
   <li><a href="#backends">TableGen backends</a>
@@ -401,6 +402,14 @@ which case the user must specify it explicitly.</dd>
 <dt><tt>list[4-7,17,2-3]</tt></dt>
   <dd>A slice of the 'list' list, including elements 4,5,6,7,17,2, and 3 from
   it.  Elements may be included multiple times.</dd>
+<dt><tt>foreach &lt;var&gt; = &lt;list&gt; in { &lt;body&gt; }</tt></dt>
+<dt><tt>foreach &lt;var&gt; = &lt;list&gt; in &lt;def&gt;</tt></dt>
+  <dd> Replicate &lt;body&gt; or &lt;def&gt;, replacing instances of
+  &lt;var&gt; with each value in &lt;list&gt;.  &lt;var&gt; is scoped at the
+  level of the <tt>foreach</tt> loop and must not conflict with any other object
+  introduced in &lt;body&gt; or &lt;def&gt;.  Currently only <tt>def</tt>s are
+  expanded within &lt;body&gt;.
+  </dd>
 <dt><tt>(DEF a, b)</tt></dt>
   <dd>a dag value.  The first element is required to be a record definition, the
   remaining elements in the list may be arbitrary other values, including nested
@@ -880,6 +889,39 @@ several levels of multiclass instanciations. This also avoids the need of using
 </pre>
 </div>
 
+<!-- -------------------------------------------------------------------------->
+<h4>
+  <a name="foreach">Looping</a>
+</h4>
+
+<div>
+<p>TableGen supports the '<tt>foreach</tt>' block, which textually replicates
+the loop body, substituting iterator values for iterator references in the
+body.  Example:</p>
+
+<div class="doc_code">
+<pre>
+<b>foreach</b> i = [0, 1, 2, 3] in {
+  <b>def</b> R#i : Register&lt;...&gt;;
+  <b>def</b> F#i : Register&lt;...&gt;;
+}
+</pre>
+</div>
+
+<p>This will create objects <tt>R0</tt>, <tt>R1</tt>, <tt>R2</tt> and
+<tt>R3</tt>.  <tt>foreach</tt> blocks may be nested. If there is only
+one item in the body the braces may be elided:</p>
+
+<div class="doc_code">
+<pre>
+<b>foreach</b> i = [0, 1, 2, 3] in
+  <b>def</b> R#i : Register&lt;...&gt;;
+
+</pre>
+</div>
+
+</div>
+
 </div>
 
 </div>