Document new intrinsics

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@11438 91177308-0d34-0410-b5e6-96231b3b80d8

docs/LangRef.html

@@ -95,10 +95,17 @@
           <li><a href="#i_va_copy">'<tt>llvm.va_copy</tt>'  Intrinsic</a></li>
         </ol>
       </li>
+      <li><a href="#int_codegen">Code Generator Intrinsics</a>
+        <ol>
+          <li><a href="#i_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
+          <li><a href="#i_frameaddress">'<tt>llvm.frameaddress</tt>'   Intrinsic</a></li>
+        </ol>
+      </li>
       <li><a href="#int_libc">Standard C Library Intrinsics</a>
         <ol>
           <li><a href="#i_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a></li>
           <li><a href="#i_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a></li>
+          <li><a href="#i_memset">'<tt>llvm.memset</tt>' Intrinsic</a></li>
         </ol>
       </li>
       <li><a href="#int_debugger">Debugger intrinsics</a>
@@ -1733,6 +1740,107 @@ element into the returned list.  This intrinsic is necessary because the <tt><a
 complex and require memory allocation, for example.</p>
 </div>
 
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+  <a name="int_codegen">Code Generator Intrinsics</a>
+</div>
+
+<div class="doc_text">
+<p>
+These intrinsics are provided by LLVM to expose special features that may only
+be implemented with code generator support.
+</p>
+
+</div>
+
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection">
+  <a name="i_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
+</div>
+
+<div class="doc_text">
+
+<h5>Syntax:</h5>
+<pre>
+  call void* ()* %llvm.returnaddress(uint &lt;level&gt;)
+</pre>
+
+<h5>Overview:</h5>
+
+<p>
+The '<tt>llvm.returnaddress</tt>' intrinsic returns a target-specific value
+indicating the return address of the current function or one of its callers.
+</p>
+
+<h5>Arguments:</h5>
+
+<p>
+The argument to this intrinsic indicates which function to return the address
+for.  Zero indicates the calling function, one indicates its caller, etc.  The
+argument is <b>required</b> to be a constant integer value.
+</p>
+
+<h5>Semantics:</h5>
+
+<p>
+The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
+the return address of the specified call frame, or zero if it cannot be
+identified.  The value returned by this intrinsic is likely to be incorrect or 0
+for arguments other than zero, so it should only be used for debugging purposes.
+</p>
+
+<p>
+Note that calling this intrinsic does not prevent function inlining or other
+aggressive transformations, so the value returned may not that of the obvious
+source-language caller.
+</p>
+</div>
+
+
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection">
+  <a name="i_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
+</div>
+
+<div class="doc_text">
+
+<h5>Syntax:</h5>
+<pre>
+  call void* ()* %llvm.frameaddress(uint &lt;level&gt;)
+</pre>
+
+<h5>Overview:</h5>
+
+<p>
+The '<tt>llvm.frameaddress</tt>' intrinsic returns the target-specific frame
+pointer value for the specified stack frame.
+</p>
+
+<h5>Arguments:</h5>
+
+<p>
+The argument to this intrinsic indicates which function to return the frame
+pointer for.  Zero indicates the calling function, one indicates its caller,
+etc.  The argument is <b>required</b> to be a constant integer value.
+</p>
+
+<h5>Semantics:</h5>
+
+<p>
+The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
+the frame address of the specified call frame, or zero if it cannot be
+identified.  The value returned by this intrinsic is likely to be incorrect or 0
+for arguments other than zero, so it should only be used for debugging purposes.
+</p>
+
+<p>
+Note that calling this intrinsic does not prevent function inlining or other
+aggressive transformations, so the value returned may not that of the obvious
+source-language caller.
+</p>
+</div>
+
+
 <!-- ======================================================================= -->
 <div class="doc_subsection">
   <a name="int_libc">Standard C Library Intrinsics</a>
@@ -1740,7 +1848,10 @@ complex and require memory allocation, for example.</p>
 
 <div class="doc_text">
 <p>
-
+LLVM provides intrinsics for a few important standard C library functions.
+These intrinsics allow source-language front-ends to pass information about the
+alignment of the pointer arguments to the code generator, providing opportunity
+for more efficient code generation.
 </p>
 
 </div>
@@ -1850,6 +1961,57 @@ be set to 0 or 1.
 </div>
 
 
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection">
+  <a name="i_memset">'<tt>llvm.memset</tt>' Intrinsic</a>
+</div>
+
+<div class="doc_text">
+
+<h5>Syntax:</h5>
+<pre>
+  call void (sbyte*, ubyte, uint, uint)* %llvm.memset(sbyte* &lt;dest&gt;, ubyte &lt;val&gt;,
+                                                      uint &lt;len&gt;, uint &lt;align&gt;)
+</pre>
+
+<h5>Overview:</h5>
+
+<p>
+The '<tt>llvm.memset</tt>' intrinsic fills a block of memory with a particular
+byte value.
+</p>
+
+<p>
+Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
+does not return a value, and takes an extra alignment argument.
+</p>
+
+<h5>Arguments:</h5>
+
+<p>
+The first argument is a pointer to the destination to fill, the second is the
+byte value to fill it with, the third argument is an (arbitrarily sized) integer
+argument specifying the number of bytes to fill, and the fourth argument is the
+known alignment of destination location.
+</p>
+
+<p>
+If the call to this intrinisic has an alignment value that is not 0 or 1, then
+the caller guarantees that the size of the copy is a multiple of the alignment
+and that the destination pointer is aligned to that boundary.
+</p>
+
+<h5>Semantics:</h5>
+
+<p>
+The '<tt>llvm.memset</tt>' intrinsic fills "len" bytes of memory starting at the
+destination location.  If the argument is known to be aligned to some boundary,
+this can be specified as the fourth argument, otherwise it should be set to 0 or
+1.
+</p>
+</div>
+
+
 <!-- ======================================================================= -->
 <div class="doc_subsection">
   <a name="int_debugger">Debugger Intrinsics</a>