<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"> <html> <head> <meta name="robots" content="index,nofollow"> <title>ToMachine - MLton Standard ML Compiler (SML Compiler)</title> <link rel="stylesheet" type="text/css" charset="iso-8859-1" media="all" href="common.css"> <link rel="stylesheet" type="text/css" charset="iso-8859-1" media="screen" href="screen.css"> <link rel="stylesheet" type="text/css" charset="iso-8859-1" media="print" href="print.css"> <link rel="Start" href="Home"> </head> <body lang="en" dir="ltr"> <script src="http://www.google-analytics.com/urchin.js" type="text/javascript"> </script> <script type="text/javascript"> _uacct = "UA-833377-1"; urchinTracker(); </script> <table bgcolor = lightblue cellspacing = 0 style = "border: 0px;" width = 100%> <tr> <td style = " border: 0px; color: darkblue; font-size: 150%; text-align: left;"> <a class = mltona href="Home">MLton MLTONWIKIVERSION</a> <td style = " border: 0px; font-size: 150%; text-align: center; width: 50%;"> ToMachine <td style = " border: 0px; text-align: right;"> <table cellspacing = 0 style = "border: 0px"> <tr style = "vertical-align: middle;"> </table> <tr style = "background-color: white;"> <td colspan = 3 style = " border: 0px; font-size:70%; text-align: right;"> <a href = "Home">Home</a> <a href = "TitleIndex">Index</a> </table> <div id="content" lang="en" dir="ltr"> ToMachine is a translation pass from the <a href="RSSA">RSSA</a> <a href="IntermediateLanguage">IntermediateLanguage</a> to the <a href="Machine">Machine</a> <a href="IntermediateLanguage">IntermediateLanguage</a>. <h2 id="head-55f8ebc805e65b5b71ddafdae390e3be2bcd69af">Description</h2> <p> This pass converts from a <a href="RSSA">RSSA</a> program into a <a href="Machine">Machine</a> program. </p> <p> It uses <a href="AllocateRegisters">AllocateRegisters</a>, <a href="Chunkify">Chunkify</a>, and <a href="ParallelMove">ParallelMove</a>. </p> <h2 id="head-8781d615fd77be9578225c40ac67b9471394cced">Implementation</h2> <a href = "http://mlton.org/cgi-bin/viewsvn.cgi/mlton/tags/on-MLTONWIKIVERSION-release/mlton/backend/backend.sig?view=markup"><img src="moin-www.png" alt="[WWW]" height="11" width="11">backend.sig</a> <a href = "http://mlton.org/cgi-bin/viewsvn.cgi/mlton/tags/on-MLTONWIKIVERSION-release/mlton/backend/backend.fun?view=markup"><img src="moin-www.png" alt="[WWW]" height="11" width="11">backend.fun</a> <h2 id="head-35ec00231a68203708e39f0e2cc10b50c6bf62de">Details and Notes</h2> <p> Because the MLton runtime system is shared by all codegens, it is most convenient to decide on stack layout <em>before</em> any codegen takes over. In particular, we compute all the stack frame info for each <a href="RSSA">RSSA</a> function, including stack size, <a href="GarbageCollection">garbage collector</a> masks for each frame, etc. To do so, the <a href="Machine">Machine</a> <a href="IntermediateLanguage">IntermediateLanguage</a> imagines an abstract machine with an infinite number of (pseudo-)registers of every size. A liveness analysis determines, for each variable, whether or not it is live across a point where the runtime system might take over (for example, any garbage collection point) or a non-tail call to another <a href="RSSA">RSSA</a> function. Those that are live go on the stack, while those that aren't live go into psuedo-registers. From this information, we know all we need to about each stack frame. On the downside, nothing further on is allowed to change this stack info; it is set in stone. </p> </div> <p> <hr> Last edited on 2006-11-28 21:24:34 by <span title="GS5006.SP.CS.CMU.EDU">JakeDonham</span>. </body></html>