add support, testcases, and dox for the new GHC calling

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

diff --git a/docs/LangRef.html b/docs/LangRef.html
index eec06fcc023f886e6f10b762758ab5ec11a2b9ba..adaf44ab87033794cfe2dfc9c8adc9cd933f519c 100644 (file)
--- a/docs/LangRef.html
+++ b/docs/LangRef.html
@@ -691,9 +691,9 @@ define i32 @main() {                                        <i>; i32()* </i>
       target, without having to conform to an externally specified ABI
       (Application Binary Interface).
       <a href="CodeGenerator.html#tailcallopt">Tail calls can only be optimized
-      when this convention is used.</a>  This calling convention does not
-      support varargs and requires the prototype of all callees to exactly match
-      the prototype of the function definition.</dd>
+      when this or the GHC convention is used.</a>  This calling convention
+      does not support varargs and requires the prototype of all callees to
+      exactly match the prototype of the function definition.</dd>
 
   <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
   <dd>This calling convention attempts to make code in the caller as efficient
@@ -703,6 +703,26 @@ define i32 @main() {                                        <i>; i32()* </i>
       does not support varargs and requires the prototype of all callees to
       exactly match the prototype of the function definition.</dd>
 
+  <dt><b>"<tt>cc <em>10</em></tt>" - GHC convention</b>:</dt>
+  <dd>This calling convention has been implemented specifically for use by the
+      <a href="http://www.haskell.org/ghc">Glasgow Haskell Compiler (GHC)</a>.
+      It passes everything in registers, going to extremes to achieve this by
+      disabling callee save registers. This calling convention should not be
+      used lightly but only for specific situations such as an alternative to
+      the <em>register pinning</em> performance technique often used when
+      implementing functional programming languages.At the moment only X86
+      supports this convention and it has the following limitations:
+      <ul>
+        <li>On <em>X86-32</em> only supports up to 4 bit type parameters. No
+            floating point types are supported.</li>
+        <li>On <em>X86-64</em> only supports up to 10 bit type parameters and
+            6 floating point parameters.</li>
+      </ul>
+      This calling convention supports
+      <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> but
+      requires both the caller and callee are using it.
+  </dd>
+
   <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
   <dd>Any calling convention may be specified by number, allowing
       target-specific calling conventions to be used.  Target specific calling