<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=us-ascii">
<meta name="Generator" content="Microsoft Word 15 (filtered medium)">
<style><!--
/* Font Definitions */
@font-face
{font-family:"Cambria Math";
panose-1:2 4 5 3 5 4 6 3 2 4;}
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
@font-face
{font-family:Consolas;
panose-1:2 11 6 9 2 2 4 3 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0in;
margin-bottom:.0001pt;
font-size:11.0pt;
font-family:"Calibri","sans-serif";}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:#0563C1;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:#954F72;
text-decoration:underline;}
p.MsoListParagraph, li.MsoListParagraph, div.MsoListParagraph
{mso-style-priority:34;
margin-top:0in;
margin-right:0in;
margin-bottom:0in;
margin-left:.5in;
margin-bottom:.0001pt;
font-size:11.0pt;
font-family:"Calibri","sans-serif";}
span.EmailStyle17
{mso-style-type:personal-compose;
font-family:"Calibri","sans-serif";
color:windowtext;}
.MsoChpDefault
{mso-style-type:export-only;}
@page WordSection1
{size:8.5in 11.0in;
margin:1.0in 1.0in 1.0in 1.0in;}
div.WordSection1
{page:WordSection1;}
/* List Definitions */
@list l0
{mso-list-id:777025832;
mso-list-type:hybrid;
mso-list-template-ids:-709478328 67698705 67698713 67698715 67698703 67698713 67698715 67698703 67698713 67698715;}
@list l0:level1
{mso-level-text:"%1\)";
mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-.25in;}
@list l0:level2
{mso-level-number-format:alpha-lower;
mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-.25in;}
@list l0:level3
{mso-level-number-format:roman-lower;
mso-level-tab-stop:none;
mso-level-number-position:right;
text-indent:-9.0pt;}
@list l0:level4
{mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-.25in;}
@list l0:level5
{mso-level-number-format:alpha-lower;
mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-.25in;}
@list l0:level6
{mso-level-number-format:roman-lower;
mso-level-tab-stop:none;
mso-level-number-position:right;
text-indent:-9.0pt;}
@list l0:level7
{mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-.25in;}
@list l0:level8
{mso-level-number-format:alpha-lower;
mso-level-tab-stop:none;
mso-level-number-position:left;
text-indent:-.25in;}
@list l0:level9
{mso-level-number-format:roman-lower;
mso-level-tab-stop:none;
mso-level-number-position:right;
text-indent:-9.0pt;}
ol
{margin-bottom:0in;}
ul
{margin-bottom:0in;}
--></style><!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</o:shapelayout></xml><![endif]-->
</head>
<body lang="EN-US" link="#0563C1" vlink="#954F72">
<div class="WordSection1">
<p class="MsoNormal">Hello,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I’m looking for some information about the Java script interpreter ASM backend, aka OfflineAsm. <o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">First a bit of background information; the code I have been using is about a year old, on several platforms we don’t run with JIT and won’t be able to enable it. This means that we’ve been using the
<span style="font-size:9.0pt;font-family:Consolas;color:#1E1E1E;background:white;mso-highlight:white">
LLINT_C_LOOP</span><span style="font-size:9.0pt;font-family:Consolas;color:#1E1E1E">
</span>path in these cases. It was considered that the ASM backend may be able to improve performance in this case, currently I’m taking a look at how things are done in a more recent snapshot of the trunk to be sure this development effort will be going in
the right direction on what is done there. As a side note I see that <span style="font-size:9.0pt;font-family:Consolas;color:#1E1E1E;background:white;mso-highlight:white">
LLINT_C_LOOP</span><span style="font-size:9.0pt;font-family:Consolas;color:#1E1E1E">
</span>has been replaced with <span style="font-size:9.0pt;font-family:Consolas;color:#1E1E1E;background:white;mso-highlight:white">
#if !ENABLE(JIT)</span><span style="font-size:9.0pt;font-family:Consolas;color:#1E1E1E">
</span>which I guess is pretty much how it has always behaved.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">So my questions are:<o:p></o:p></p>
<p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l0 level1 lfo1"><![if !supportLists]><span style="mso-list:Ignore">1)<span style="font:7.0pt "Times New Roman"">
</span></span><![endif]>How is the ASM backend intended to be used? Is there a doc that covers this?<o:p></o:p></p>
<p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l0 level1 lfo1"><![if !supportLists]><span style="mso-list:Ignore">2)<span style="font:7.0pt "Times New Roman"">
</span></span><![endif]>Can I essentially move from the “C LOOP” to neither “C LOOP” nor “JIT”? or is the ASM backend dependent on JIT itself? It appears this would be handled by the defines in Source\JavaScriptCore\llint\LLIntOfflineAsmConfig.h<o:p></o:p></p>
<p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l0 level1 lfo1"><![if !supportLists]><span style="mso-list:Ignore">3)<span style="font:7.0pt "Times New Roman"">
</span></span><![endif]>If JIT is expected to use the ASM backend is there a way this can be worked around?<o:p></o:p></p>
<p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l0 level1 lfo1"><![if !supportLists]><span style="mso-list:Ignore">4)<span style="font:7.0pt "Times New Roman"">
</span></span><![endif]>Should I actually expect a performance increase compared to the “C LOOP”?<o:p></o:p></p>
<p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l0 level1 lfo1"><![if !supportLists]><span style="mso-list:Ignore">5)<span style="font:7.0pt "Times New Roman"">
</span></span><![endif]>Are there any other suggestions on how to improve performance of Java script code in a non-JIT port?<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Thanks for any feedback<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Chris Vienneau<o:p></o:p></p>
</div>
</body>
</html>