<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:st1="urn:schemas-microsoft-com:office:smarttags" 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 11 (filtered medium)">
<base href="x-msg://14347/">
<!--[if !mso]>
<style>
v\:* {behavior:url(#default#VML);}
o\:* {behavior:url(#default#VML);}
w\:* {behavior:url(#default#VML);}
.shape {behavior:url(#default#VML);}
</style>
<![endif]--><o:SmartTagType
namespaceuri="urn:schemas-microsoft-com:office:smarttags" name="City"/>
<o:SmartTagType namespaceuri="urn:schemas-microsoft-com:office:smarttags"
name="place"/>
<o:SmartTagType namespaceuri="urn:schemas-microsoft-com:office:smarttags"
name="PersonName"/>
<!--[if !mso]>
<style>
st1\:*{behavior:url(#default#ieooui) }
</style>
<![endif]-->
<style>
<!--
/* Font Definitions */
@font-face
{font-family:Tahoma;
panose-1:2 11 6 4 3 5 4 4 2 4;}
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0cm;
margin-bottom:.0001pt;
font-size:12.0pt;
font-family:"Times New Roman";}
a:link, span.MsoHyperlink
{color:blue;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{color:blue;
text-decoration:underline;}
span.EmailStyle18
{mso-style-type:personal-reply;
font-family:Arial;
color:navy;}
@page Section1
{size:595.3pt 841.9pt;
margin:2.0cm 42.5pt 2.0cm 3.0cm;}
div.Section1
{page:Section1;}
-->
</style>
</head>
<body lang=RU link=blue vlink=blue style='word-wrap: break-word;-webkit-nbsp-mode: space;
-webkit-line-break: after-white-space'>
<div class=Section1>
<p class=MsoNormal><font size=2 color=navy face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:navy'>Hello Jim,<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:navy'>As variant, add the GetExternalSymbolAddr()
to the RTDyldMemoryManager.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:navy'>The memory manager linked
to a target system, its emit sections to the target system, so its can known
external symbol addresses.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:navy'>The MCJITMemoryManager
will use ExecutionEngine for getting addresses, another memory manager will use
their methods, or just return 0 if this feature not supported.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:navy'>I can add these changes
to the patch quickly.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:navy'>Thank you,<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:navy'>Danil<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<div>
<div class=MsoNormal align=center style='text-align:center'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'>
<hr size=2 width="100%" align=center tabindex=-1>
</span></font></div>
<p class=MsoNormal><b><font size=2 face=Tahoma><span style='font-size:10.0pt;
font-family:Tahoma;font-weight:bold'>From:</span></font></b><font size=2
face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'> <st1:PersonName
w:st="on">Jim Grosbach</st1:PersonName> [mailto:grosbach@apple.com] <br>
<b><span style='font-weight:bold'>Sent:</span></b> Tuesday, February 28, 2012
4:36 AM<br>
<b><span style='font-weight:bold'>To:</span></b> Kaylor, Andrew<br>
<b><span style='font-weight:bold'>Cc:</span></b> Danil Malyshev; <st1:PersonName
w:st="on">llvm-commits@cs.uiuc.edu</st1:PersonName><br>
<b><span style='font-weight:bold'>Subject:</span></b> Re: RuntimeDyLd new
features</span></font><o:p></o:p></p>
</div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
<div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>On Feb 23, 2012, at 2:08 PM, "Kaylor, Andrew" <<a
href="mailto:andrew.kaylor@intel.com">andrew.kaylor@intel.com</a>> wrote:<o:p></o:p></span></font></p>
</div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><br>
<br>
<o:p></o:p></span></font></p>
<div link=blue vlink=purple style='orphans: 2;text-align:-webkit-auto;
widows: 2;-webkit-text-size-adjust: auto;-webkit-text-stroke-width: 0px;
word-spacing:0px'>
<div>
<p class=MsoNormal><font size=2 color="#1f497d" face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:#1F497D'>These changes look
good to me.<u1:p></u1:p></span></font><font color=black><span lang=EN-US
style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color="#1f497d" face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:#1F497D'><u1:p> </u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color="#1f497d" face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:#1F497D'>The test-globall.ll
test is failing because your code doesn’t handle sections without bits in the
object image and needing zero-initialization (at least, that’s why it fails on
ELF). I believe that the stubs.ll and test-common-symbols.ll tests are both
failing because common symbols aren’t being properly handled.<u1:p></u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color="#1f497d" face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:#1F497D'><u1:p> </u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color="#1f497d" face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:#1F497D'>As I mentioned
before, I think the common symbol issue requires a bit of restructuring to
allow format specific handling of part of the common symbol processing. I
have a fix ready which addresses this for ELF and would provide most of the fix
and the necessary interface to fix it on MachO. Basically, my fix makes a
list of common symbols, allocates memory for the common symbols and calls a
virtual function to update the symbol address in the SymbolRef. MachO
would just need an implementation of the function to test a symbol to see if it
is a common symbol, and an implementation of the function to update the address.<u1:p></u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color="#1f497d" face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:#1F497D'><u1:p> </u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color="#1f497d" face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:#1F497D'>I also have a
general fix ready for the nobits/zero-init problem.<u1:p></u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color="#1f497d" face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:#1F497D'><u1:p> </u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color="#1f497d" face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:#1F497D'>Therefore, I think
it would be OK to have this patch committed as is, with the understanding that
these problems would be fixed shortly afterward. Again, that is assuming
that the changes are otherwise acceptable to Jim.<u1:p></u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color="#1f497d" face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:#1F497D'><u1:p> </u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>I'm generally OK with that, with one exception. Adding a back-reference
to the ExecutionEngine to RuntimeDyld is a pretty bad layering violation, as
alluded to in the code comments. I'm not comfortable with that part going in
as-is.<o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>We need an interface to the RuntimeDyld which will allow the client to
query for unresolved symbols and to<o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>a) provide an address for them if they are true external symbols, or<o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>b) provide a module which supplies the symbols.<o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>In a normal hosted JIT environment, the second option is our vector to
lazy compilation. The JIT builds the entry point, then queries for unresolved
symbols. It creates a module containing each that has a compile-stub as an
instantiation.<o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>The key is that the behavior is driven top-down from the client. There
shouldn't be calls back up from the RuntimeDyld to either the JIT or the
ExecutionEngine.<o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>-Jim<o:p></o:p></span></font></p>
</div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><br>
<br>
<o:p></o:p></span></font></p>
<div link=blue vlink=purple style='orphans: 2;text-align:-webkit-auto;
widows: 2;-webkit-text-size-adjust: auto;-webkit-text-stroke-width: 0px;
word-spacing:0px'>
<div>
<p class=MsoNormal><font size=2 color="#1f497d" face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:#1F497D'>I would like to
discuss the way that the MCJIT-specific tests are handled, but we can talk
about that later.<u1:p></u1:p></span></font><font color=black><span lang=EN-US
style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color="#1f497d" face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:#1F497D'><u1:p> </u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color="#1f497d" face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:#1F497D'>-Andy<u1:p></u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color="#1f497d" face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:#1F497D'><u1:p> </u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0cm 0cm 0cm;
border-width:initial;border-color:initial;border-image: initial'>
<div>
<p class=MsoNormal><b><font size=2 color=black face=Tahoma><span lang=EN-US
style='font-size:10.0pt;font-family:Tahoma;color:black;font-weight:bold'>From:</span></font></b><span
class=apple-converted-space><font size=2 color=black face=Tahoma><span
lang=EN-US style='font-size:10.0pt;font-family:Tahoma;color:black'> </span></font></span><font
size=2 color=black face=Tahoma><span lang=EN-US style='font-size:10.0pt;
font-family:Tahoma;color:black'>Danil Malyshev
[mailto:dmalyshev@accesssoftek.com]<span class=apple-converted-space> </span><br>
<b><span style='font-weight:bold'>Sent:</span></b><span
class=apple-converted-space> </span>Wednesday, February 22, 2012 4:08 PM<br>
<b><span style='font-weight:bold'>To:</span></b><span
class=apple-converted-space> </span><st1:PersonName w:st="on">Jim Grosbach</st1:PersonName>;
Kaylor, Andrew; <a href="mailto:llvm-commits@cs.uiuc.edu">llvm-commits@cs.uiuc.edu</a><br>
<b><span style='font-weight:bold'>Subject:</span></b><span
class=apple-converted-space> </span>RE: RuntimeDyLd new features<u1:p></u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
</div>
</div>
<div><u1:p>
<p class=MsoNormal><font size=3 color=black face="Times New Roman"><span
lang=EN-US style='font-size:12.0pt;color:black'> <o:p></o:p></span></font></p>
</u1:p></div>
<div>
<p class=MsoNormal><font size=2 color=navy face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:navy'>Hi Jim,<u1:p></u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=navy face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:navy'><u1:p> </u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=navy face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:navy'>The MCJIT with changed
RuntimeDyLd passes most of ExecutionEngine tests on Mac OS, except of 3 tests:
stubs.ll, test-common-symbols.ll and test-global.ll.<u1:p></u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=navy face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:navy'>And I will work to ensure
that these three tests are also passed.<u1:p></u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=navy face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:navy'>Please look
01-RuntimeDyLd-02.patch of the previous letter, can I commit it?<u1:p></u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=navy face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:navy'><u1:p> </u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=navy face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:navy'><u1:p> </u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=navy face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:navy'><u1:p> </u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=navy face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:navy'>Regards,<u1:p></u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=navy face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:navy'>Danil<u1:p></u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=navy face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:navy'><u1:p> </u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=navy face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:navy'><u1:p> </u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<div class=MsoNormal align=center style='text-align:center'><font size=3
color=black face="Times New Roman"><span style='font-size:12.0pt;color:black'>
<hr size=2 width="100%" align=center>
</span></font></div>
<div>
<p class=MsoNormal><b><font size=2 color=black face=Tahoma><span
style='font-size:10.0pt;font-family:Tahoma;color:black;font-weight:bold'>From:</span></font></b><span
class=apple-converted-space><font size=2 color=black face=Tahoma><span
style='font-size:10.0pt;font-family:Tahoma;color:black'> </span></font></span><font
size=2 color=black face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma;
color:black'>Kaylor, Andrew [mailto:andrew.kaylor@intel.com]<span
class=apple-converted-space> </span><br>
<b><span style='font-weight:bold'>Sent:</span></b><span
class=apple-converted-space> </span>Saturday, February 18, 2012 5:41 AM<br>
<b><span style='font-weight:bold'>To:</span></b><span
class=apple-converted-space> </span>Danil Malyshev; <a
href="mailto:llvm-commits@cs.uiuc.edu">llvm-commits@cs.uiuc.edu</a><br>
<b><span style='font-weight:bold'>Cc:</span></b><span
class=apple-converted-space> </span><st1:PersonName w:st="on">Jim Grosbach</st1:PersonName><br>
<b><span style='font-weight:bold'>Subject:</span></b><span
class=apple-converted-space> </span>RE: RuntimeDyLd new features</span></font><font
color=black><span lang=EN-US style='color:black'><u1:p></u1:p><o:p></o:p></span></font></p>
</div>
</div>
<div>
<p class=MsoNormal><font size=3 color=black face="Times New Roman"><span
style='font-size:12.0pt;color:black'><u1:p> </u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color="#1f497d" face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:#1F497D'>Hi Danil,<u1:p></u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color="#1f497d" face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:#1F497D'><u1:p> </u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color="#1f497d" face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:#1F497D'>I’d like to make
clear that if Jim is OK with the impact of your patch on MachO JIT loading then
I’d be happy for you to proceed with your patch, incorporating my comments
below, and we will withdraw our previous uncommitted patch and I will merge the
GDB JIT debugging integration code we have with your changes after they have
been committed.<u1:p></u1:p></span></font><font color=black><span lang=EN-US
style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color="#1f497d" face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:#1F497D'><u1:p> </u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color="#1f497d" face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:#1F497D'>Thanks,<u1:p></u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color="#1f497d" face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:#1F497D'>Andy<u1:p></u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color="#1f497d" face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:#1F497D'><u1:p> </u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color="#1f497d" face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:#1F497D'><u1:p> </u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0cm 0cm 0cm;
border-width:initial;border-color:initial;border-image: initial'>
<div>
<p class=MsoNormal><b><font size=2 color=black face=Tahoma><span lang=EN-US
style='font-size:10.0pt;font-family:Tahoma;color:black;font-weight:bold'>From:</span></font></b><span
class=apple-converted-space><font size=2 color=black face=Tahoma><span
lang=EN-US style='font-size:10.0pt;font-family:Tahoma;color:black'> </span></font></span><font
size=2 color=black face=Tahoma><span lang=EN-US style='font-size:10.0pt;
font-family:Tahoma;color:black'><a
href="mailto:llvm-commits-bounces@cs.uiuc.edu">llvm-commits-bounces@cs.uiuc.edu</a>
[mailto:llvm-commits-bounces@cs.uiuc.edu]<span class=apple-converted-space> </span><b><span
style='font-weight:bold'>On Behalf Of<span class=apple-converted-space> </span></span></b>Kaylor,
Andrew<br>
<b><span style='font-weight:bold'>Sent:</span></b><span
class=apple-converted-space> </span>Tuesday, February 14, 2012 4:53 PM<br>
<b><span style='font-weight:bold'>To:</span></b><span
class=apple-converted-space> </span>Danil Malyshev; <a
href="mailto:llvm-commits@cs.uiuc.edu">llvm-commits@cs.uiuc.edu</a><br>
<b><span style='font-weight:bold'>Subject:</span></b><span
class=apple-converted-space> </span>Re: [llvm-commits] RuntimeDyLd new
features<u1:p></u1:p></span></font><font color=black><span lang=EN-US
style='color:black'><o:p></o:p></span></font></p>
</div>
</div>
</div>
<div><u1:p>
<p class=MsoNormal><font size=3 color=black face="Times New Roman"><span
lang=EN-US style='font-size:12.0pt;color:black'> <o:p></o:p></span></font></p>
</u1:p></div>
<div>
<p class=MsoNormal><font size=2 color="#1f497d" face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:#1F497D'>Hi Danil,<u1:p></u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color="#1f497d" face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:#1F497D'><u1:p> </u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color="#1f497d" face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:#1F497D'>I've been working
with your patch also. Mostly, it looks pretty good. I've been able
to layer most of our added functionality on top of it, and I have GDB
integration working and our integration tests passing. There are a few
issues I'd like to bring up, however.<u1:p></u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color="#1f497d" face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:#1F497D'><u1:p> </u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color="#1f497d" face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:#1F497D'>The first thing I
saw with your patch is that I had problems loading images that were generated
with debug information included. In particular, applying relocations to
debug sections using the actual addresses of the debug sections causes
problems. This is really a small issue because, as you mentioned, debug
sections don't need to be loaded. I worked around this problem by adding
a new member function to SectionRef to query whether or not the section is
required for execution. This is fairly trivial for ELF.<u1:p></u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color="#1f497d" face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:#1F497D'><u1:p> </u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color="#1f497d" face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:#1F497D'>A related problem is
that your code does not properly handle sections which are only represented by
a header in the ELF image (that is, SHT_NOBITS sections) or sections which need
to be zero-initialized. I worked around these problems using the existing
isBSS() member in SectionRef, but it would probably be better to split these
two concepts.<u1:p></u1:p></span></font><font color=black><span lang=EN-US
style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color="#1f497d" face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:#1F497D'><u1:p> </u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color="#1f497d" face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:#1F497D'>Similarly, your code
does not handle symbols which are marked as relative to the SHN_COMMON
section. Fixing this is a bit more complicated. I think we can
probably build a table of these symbols in the RuntimeDyldImpl class by adding
a new member to SectionRef, but we'll need deeper access to the format-specific
classes to update the symbol addresses. I'm working on an implementation
of this for ELF.<u1:p></u1:p></span></font><font color=black><span lang=EN-US
style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color="#1f497d" face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:#1F497D'><u1:p> </u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color="#1f497d" face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:#1F497D'>The code which loads
the sections is currently assuming pointer-sized alignment for all
sections. I ran into a case using floating point numbers where 16-byte
alignment was required. This is a fairly simple fix as the alignment
value is accessible through SectionRef.<u1:p></u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color="#1f497d" face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:#1F497D'><u1:p> </u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color="#1f497d" face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:#1F497D'>I think it would be
worthwhile adding an function to SectionRef to query whether or not a section
contains code rather than the current algorithmic method you are using.<u1:p></u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color="#1f497d" face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:#1F497D'><u1:p> </u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color="#1f497d" face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:#1F497D'>In a few places you
are using uintptr_t or uint8_t* in places that will restrict cross-architecture
JITing. The TargetAddr in the SectionEntry structure is an example that
comes to mind.<u1:p></u1:p></span></font><font color=black><span lang=EN-US
style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color="#1f497d" face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:#1F497D'><u1:p> </u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color="#1f497d" face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:#1F497D'>The distinction
between code and data for memory allocation will be important going
forward. I think it would be better to fix the existing bug that to
disable the specific allocations.<u1:p></u1:p></span></font><font color=black><span
lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color="#1f497d" face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:#1F497D'><u1:p> </u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color="#1f497d" face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:#1F497D'>In
RuntimeDyld::loadObject, in the "parse and process relocations loop"
"SectionID == 0" is used to identify sections that need to be looked
up, but zero is a valid SectionID. For that section, it goes into the
lookup for every relocation.<u1:p></u1:p></span></font><font color=black><span
lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color="#1f497d" face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:#1F497D'><u1:p> </u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color="#1f497d" face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:#1F497D'>I'm continuing to
work on integrating our code, including some that hasn't yet been submitted to
the list for review, with your changes. I need to go over what I've done
with the rest of my co-workers, but I wanted to give you a progress update now.<u1:p></u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color="#1f497d" face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:#1F497D'><u1:p> </u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color="#1f497d" face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:#1F497D'>-Andy<u1:p></u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color="#1f497d" face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:#1F497D'><u1:p> </u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0cm 0cm 0cm;
border-width:initial;border-color:initial;border-image: initial'>
<div>
<p class=MsoNormal><b><font size=2 color=black face=Tahoma><span lang=EN-US
style='font-size:10.0pt;font-family:Tahoma;color:black;font-weight:bold'>From:</span></font></b><span
class=apple-converted-space><font size=2 color=black face=Tahoma><span
lang=EN-US style='font-size:10.0pt;font-family:Tahoma;color:black'> </span></font></span><font
size=2 color=black face=Tahoma><span lang=EN-US style='font-size:10.0pt;
font-family:Tahoma;color:black'>Danil Malyshev
[mailto:dmalyshev@accesssoftek.com]<span class=apple-converted-space> </span><br>
<b><span style='font-weight:bold'>Sent:</span></b><span
class=apple-converted-space> </span>Tuesday, February 14, 2012 10:30 AM<br>
<b><span style='font-weight:bold'>To:</span></b><span
class=apple-converted-space> </span>Kaylor, Andrew; <a
href="mailto:llvm-commits@cs.uiuc.edu">llvm-commits@cs.uiuc.edu</a><br>
<b><span style='font-weight:bold'>Cc:</span></b><span
class=apple-converted-space> </span><st1:PersonName w:st="on">Jim Grosbach</st1:PersonName><br>
<b><span style='font-weight:bold'>Subject:</span></b><span
class=apple-converted-space> </span>RE: RuntimeDyLd new features<u1:p></u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
</div>
</div>
<div><u1:p>
<p class=MsoNormal><font size=3 color=black face="Times New Roman"><span
lang=EN-US style='font-size:12.0pt;color:black'> <o:p></o:p></span></font></p>
</u1:p></div>
<div>
<p class=MsoNormal><font size=2 color=navy face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:navy'>Hi Andrew,<u1:p></u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=navy face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:navy'><u1:p> </u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=navy face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:navy'>Thank you for the
detailed explanation.<u1:p></u1:p></span></font><font color=black><span
lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=navy face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:navy'>I have carefully studied
your patch and DyldELFObject.<u1:p></u1:p></span></font><font color=black><span
lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=navy face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:navy'>A gdb support is very
important and it's actually a big step for MCJIT. I like your patch, its
loadObject() looks faster than my. But I see one big conceptual problem.<u1:p></u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=navy face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:navy'><u1:p> </u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=navy face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:navy'>The RuntimeDyLd was
developed as a linker, which is able to prepare data for running on another
platform. The RuntimeDyldMachO largely implements it.<u1:p></u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=navy face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:navy'>In the RuntimeDyldELF you
went the other way. Now it is very far from remote execution. And even if the
object file will be emitted with RTDyldMemoryManager, it is not a good idea:
(1) remote execution doesn't need many parts of object file, such as debugging
information, headers, section table and etc, (2) some sections is code and must
has execution permit, some sections is data without execution permit, so the
best way is use a different methods for emits different type of sections.<u1:p></u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=navy face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:navy'>If your patch will be
committed, we obtain a RuntimeDyldMachO and RuntimeDyldELF, which different
principles and a different results. And most likely, for ELF will never be
fully realization for remote execution.<u1:p></u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=navy face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:navy'><u1:p> </u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=navy face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:navy'>I think another ways will
be better, just for instance, two possible solutions:<u1:p></u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=navy face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:navy'>1. Always emits the
sections required to execution with a RTDyldMemoryManager. Resolve relocation
in these sections. And if the isDebugging flag is set, then in addition, DyldELFObject::rebaseObject
make his job, except that for the sections stored by the RTDyldMemoryManager
write the correct address.<u1:p></u1:p></span></font><font color=black><span
lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=navy face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:navy'>2. Check the debug flag
at first, before load object file. If it set, just use your realization of
loadObject, otherwise - use normal way with RTDyldMemoryManager.<u1:p></u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=navy face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:navy'><u1:p> </u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=navy face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:navy'>Both alternatives have
their shortcomings, perhaps you find another solution. Also, I would be glad to
hear that Jim thinks about it.<u1:p></u1:p></span></font><font color=black><span
lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=navy face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:navy'>Now I trying to merge
your patch with my.<u1:p></u1:p></span></font><font color=black><span
lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=navy face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:navy'><u1:p> </u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=navy face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:navy'><u1:p> </u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=navy face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:navy'>Regards,<u1:p></u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=navy face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:navy'>Danil<u1:p></u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=navy face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:navy'><u1:p> </u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<div class=MsoNormal align=center style='text-align:center'><font size=3
color=black face="Times New Roman"><span style='font-size:12.0pt;color:black'>
<hr size=2 width="100%" align=center>
</span></font></div>
<div>
<p class=MsoNormal><b><font size=2 color=black face=Tahoma><span
style='font-size:10.0pt;font-family:Tahoma;color:black;font-weight:bold'>From:</span></font></b><span
class=apple-converted-space><font size=2 color=black face=Tahoma><span
style='font-size:10.0pt;font-family:Tahoma;color:black'> </span></font></span><font
size=2 color=black face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma;
color:black'>Kaylor, Andrew [mailto:andrew.kaylor@intel.com]<span
class=apple-converted-space> </span><br>
<b><span style='font-weight:bold'>Sent:</span></b><span
class=apple-converted-space> </span>Thursday, February 09, 2012 4:56 AM<br>
<b><span style='font-weight:bold'>To:</span></b><span
class=apple-converted-space> </span>Danil Malyshev; <a
href="mailto:llvm-commits@cs.uiuc.edu">llvm-commits@cs.uiuc.edu</a><br>
<b><span style='font-weight:bold'>Subject:</span></b><span
class=apple-converted-space> </span>RE: RuntimeDyLd new features</span></font><font
color=black><span lang=EN-US style='color:black'><u1:p></u1:p><o:p></o:p></span></font></p>
</div>
</div>
<div>
<p class=MsoNormal><font size=3 color=black face="Times New Roman"><span
style='font-size:12.0pt;color:black'><u1:p> </u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=black face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:black'>Hi Danil,<u1:p></u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=black face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:black'><u1:p> </u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=black face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:black'>Thanks for your efforts
in this area. As Eli Bendersky mentioned, we have a patch out for review
in this area also. I'm hopeful that we can find a convergence between our
code, your code and the code that <st1:PersonName w:st="on">Jim Grosbach</st1:PersonName>
has put in place.<u1:p></u1:p></span></font><font color=black><span lang=EN-US
style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=black face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:black'><u1:p> </u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=black face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:black'>Unfortunately, we have
been submitting our code in small chunks for ease of review and to keep things
stable, and it may not be obvious from what we've put out for review what our
intentions were or our intended solutions to the problems that were left
open. I'd like to take this opportunity to discuss the direction we we're
heading and see how it might align with what you and Jim have done.<u1:p></u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=black face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:black'><u1:p> </u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=black face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:black'>Let me first explain
what we have done, and then I'll offer specific comments on your code and
possible next steps.<u1:p></u1:p></span></font><font color=black><span
lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=black face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:black'><u1:p> </u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=black face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:black'>We have had two
primary goals: (1) to get MCJIT generated code to work correctly on Intel
architecture and help pave the way for other implementations and (2) enable
source-level debugging of JITed code with GDB. This second goal seems to
be dropping from view, but it places a few constraints on the eventual
implementation. We've had GDB integration working, BTW.<u1:p></u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=black face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:black'><u1:p> </u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=black face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:black'>In order to get GDB to
handle JITed code, we need to register an ELF object image through an interface
GDB defines. As you might expect, GDB has some peculiar expectations for
what this ELF object image should look like. In particular, we need to
set a flag in the ELF header and update the sh_addr members in the section
headers to reflect the address where the section contents reside in memory.<u1:p></u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=black face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:black'><u1:p> </u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=black face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:black'>Our most recent patch
(<a
href="http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20120130/135997.html"><font
color=purple><span style='color:purple'>http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20120130/135997.html</span></font></a>,
not yet committed) begins by copying the entire ELF image emitted by the MC
code generator into an executable buffer. This was intended as a
temporary step toward our eventual solution. It enabled us to perform
relocations in-place on the object and execute functions in place (thus
eliminating an extra copy that was previously being done). We were in the
process of implementing a smarter section-based approach, but <st1:PersonName
w:st="on">Jim Grosbach</st1:PersonName> was implementing a similar approach in
parallel and our submission ended up appearing out of step in this regard.<u1:p></u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=black face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:black'><u1:p> </u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=black face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:black'>So that's our
background. Now, returning to your patch....<u1:p></u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=black face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:black'><u1:p> </u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=black face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:black'>I like the idea of
combining as much common code as possible into the RuntimeDyldImpl class.
I'm interested to hear from users of the MachO loader if your implementation
has lost any of the specialization that they need. I think it's a
promising approach. There are some ELF-specific details that we will need
to have incorporated to re-enable GDB integration, but I expect that we'll be
able to find a way to work that in with a few well-placed overloaded function
calls.<u1:p></u1:p></span></font><font color=black><span lang=EN-US
style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=black face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:black'><u1:p> </u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=black face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:black'>I have some
reservations about the use of the basic ObjectFile interface, which has some
serious limitations. We've been working toward exposing the ELFObjectFile
template for use in the runtime loading process (as well as other unrelated
uses). It may be that this is something that can be generalized enough to
fit with your approach. My main concern in this regard is that we need to
be able to update specific entries in the ELF image, as described above.<u1:p></u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=black face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:black'><u1:p> </u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=black face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:black'>A related issue is
that section loading can be refined with some ELF-specific details. Some
sections need to have memory allocated for their contents. Other sections
can be left in place in the originally generated image. There is a good
bit of unnecessary copying going on in the existing implementation, and I'm not
clear to what extent your patch addresses that. Before the object is
loaded, it is copied into a new buffer and then the contents of each section
are copied again as we go. What I'd like is for the runtime loaders to
use the buffer into which the object is originally generated and only make
copies where it is strictly necessary. This isn't necessarily something
you need to do for your work to be acceptable, but I mention it as a likely
next step.<u1:p></u1:p></span></font><font color=black><span lang=EN-US
style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=black face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:black'><u1:p> </u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=black face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:black'>Over the next few days
I intend to apply your patch locally and try to merge our work into it.
I'll provide additional feedback as I get a better feel for what you've done.<u1:p></u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=black face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:black'><u1:p> </u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=black face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:black'>-Andy</span></font><font
color=black><span lang=EN-US style='color:black'><u1:p></u1:p><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color="#1f497d" face=Calibri><span lang=EN-US
style='font-size:11.0pt;font-family:Calibri;color:#1F497D'><u1:p> </u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0cm 0cm 0cm;
border-width:initial;border-color:initial;border-image: initial'>
<div>
<p class=MsoNormal><b><font size=2 color=black face=Tahoma><span lang=EN-US
style='font-size:10.0pt;font-family:Tahoma;color:black;font-weight:bold'>From:</span></font></b><span
class=apple-converted-space><font size=2 color=black face=Tahoma><span
lang=EN-US style='font-size:10.0pt;font-family:Tahoma;color:black'> </span></font></span><font
size=2 color=black face=Tahoma><span lang=EN-US style='font-size:10.0pt;
font-family:Tahoma;color:black'><a
href="mailto:llvm-commits-bounces@cs.uiuc.edu">llvm-commits-bounces@cs.uiuc.edu</a>
[mailto:llvm-commits-bounces@cs.uiuc.edu]<span class=apple-converted-space> </span><b><span
style='font-weight:bold'>On Behalf Of<span class=apple-converted-space> </span></span></b>Danil
Malyshev<br>
<b><span style='font-weight:bold'>Sent:</span></b><span
class=apple-converted-space> </span>Tuesday, February 07, 2012 12:24 PM<br>
<b><span style='font-weight:bold'>To:</span></b><span
class=apple-converted-space> </span><a
href="mailto:llvm-commits@cs.uiuc.edu">llvm-commits@cs.uiuc.edu</a><br>
<b><span style='font-weight:bold'>Subject:</span></b><span
class=apple-converted-space> </span>[llvm-commits] RuntimeDyLd new features<u1:p></u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
</div>
</div>
<div><u1:p>
<p class=MsoNormal><font size=3 color=black face="Times New Roman"><span
lang=EN-US style='font-size:12.0pt;color:black'> <o:p></o:p></span></font></p>
</u1:p></div>
<div>
<p class=MsoNormal><font size=2 color=black face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:black'>Hello everyone,<u1:p></u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=black face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:black'><u1:p> </u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=black face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:black'>Please review the
RuntimeDyLd-01.patch.<u1:p></u1:p></span></font><font color=black><span
lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=black face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:black'>This patch makes the
following changes:<u1:p></u1:p></span></font><font color=black><span
lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=black face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:black'><u1:p> </u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=black face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:black'>1. The main works will
made in the RuntimeDyLdImpl with uses the ObjectFile class. RuntimeDyLdMachO
and RuntimeDyLdELF now only parses relocations and resolve it. This is allows
to make improvements of the RuntimeDyLd more easily. In addition the support
for COFF can be easily added.<u1:p></u1:p></span></font><font color=black><span
lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=black face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:black'><u1:p> </u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=black face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:black'>2. Added ARM relocations
to RuntimeDyLdELF.<u1:p></u1:p></span></font><font color=black><span
lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=black face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:black'><u1:p> </u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=black face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:black'>3. Added support for
stub functions for the ARM, allowing to do a <st1:City w:st="on"><st1:place
w:st="on">long branch</st1:place></st1:City>.<u1:p></u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=black face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:black'><u1:p> </u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=black face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:black'>4. Added support for
external functions that are not loaded from the object files, but can be loaded
from external libraries. Now MCJIT can correctly execute the code containing
the printf, putc, and etc.<u1:p></u1:p></span></font><font color=black><span
lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=black face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:black'> <u1:p></u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=black face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:black'>5. The sections emitted
instead functions, thanks <st1:PersonName w:st="on">Jim Grosbach</st1:PersonName>.
MemoryManager.startFunctionBody() and MemoryManager.endFunctionBody() have been
removed.<u1:p></u1:p></span></font><font color=black><span lang=EN-US
style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=black face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:black'><u1:p> </u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=black face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:black'>6.
MCJITMemoryManager.allocateDataSection() and MCJITMemoryManager. allocateCodeSection()
used JMM->allocateSpace() instead of JMM->allocateCodeSection() and
JMM->allocateDataSection(), because I got an error: "Cannot allocate an
allocated block!" with object file contains more than one code or data sections.<u1:p></u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=black face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:black'><u1:p> </u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=black face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:black'>7. Fixed ELF::R_X86_64_PC32
relocation for the case when RealOffset is negative value.<u1:p></u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=black face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:black'><u1:p> </u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=black face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:black'>8. Added new testing
folder: ExecutionEngine/MCJIT because mcjit tests can be running only for x86
and arm and it's can be filtered with dg.exp.<u1:p></u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=black face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:black'><u1:p> </u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=black face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:black'>Tested in Ubuntu x86_64,
Ubuntu armv7 and MacOS 64.<u1:p></u1:p></span></font><font color=black><span
lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=black face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:black'><u1:p> </u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=black face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:black'>Thank you,<u1:p></u1:p></span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=2 color=black face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:black'>Danil</span></font><font
color=black><span lang=EN-US style='color:black'><o:p></o:p></span></font></p>
</div>
</div>
</div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
</div>
</body>
</html>