<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:dt="uuid:C2F41010-65B3-11d1-A29F-00AA00C14882" 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=utf-8">
<meta name="Generator" content="Microsoft Word 15 (filtered medium)">
<style><!--
/* Font Definitions */
@font-face
{font-family:SimSun;
panose-1:2 1 6 0 3 1 1 1 1 1;}
@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:"\@SimSun";
panose-1:2 1 6 0 3 1 1 1 1 1;}
@font-face
{font-family:NimbusMonL-Regu;
panose-1:0 0 0 0 0 0 0 0 0 0;}
@font-face
{font-family:NimbusRomNo9L-Regu;
panose-1:0 0 0 0 0 0 0 0 0 0;}
@font-face
{font-family:NimbusRomNo9L-ReguItal;
panose-1:0 0 0 0 0 0 0 0 0 0;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0in;
margin-bottom:.0001pt;
font-size:12.0pt;
font-family:"Times New Roman",serif;}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:blue;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:purple;
text-decoration:underline;}
p.gmail-m-3279998374142032133msolistparagraph, li.gmail-m-3279998374142032133msolistparagraph, div.gmail-m-3279998374142032133msolistparagraph
{mso-style-name:gmail-m_-3279998374142032133msolistparagraph;
mso-margin-top-alt:auto;
margin-right:0in;
mso-margin-bottom-alt:auto;
margin-left:0in;
font-size:12.0pt;
font-family:"Times New Roman",serif;}
span.EmailStyle18
{mso-style-type:personal;
font-family:"Calibri",sans-serif;
color:#1F497D;}
span.EmailStyle19
{mso-style-type:personal-reply;
font-family:"Calibri",sans-serif;
color:#1F497D;}
.MsoChpDefault
{mso-style-type:export-only;
font-size:10.0pt;}
@page WordSection1
{size:8.5in 11.0in;
margin:1.0in 1.0in 1.0in 1.0in;}
div.WordSection1
{page:WordSection1;}
--></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="blue" vlink="purple">
<div class="WordSection1">
<p class="MsoNormal"><a name="_MailEndCompose"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Hi Peter,<o:p></o:p></span></a></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Good news. The --apply-dynamic-relocs works for me. I finally enable the clang + ld.lld for Uefi firmware build. Thank you very much!<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Also many thanks to Rui.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">My next target will be the lld-link enabling. Will let you two know my progress.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<div>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Thanks<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Arial",sans-serif;color:#1F497D">Steven Shi</span></b><b><span style="font-size:10.0pt;font-family:"Arial",sans-serif;color:#1F497D"><o:p></o:p></span></b></p>
<p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Arial",sans-serif;color:#1F497D">Intel\SSG\FID\Firmware Infrastructure</span></b><b><span style="font-family:"Arial",sans-serif;color:#1F497D"><o:p></o:p></span></b></p>
</div>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<div style="border:none;border-left:solid blue 1.5pt;padding:0in 0in 0in 4.0pt">
<div>
<div style="border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0in 0in 0in">
<p class="MsoNormal"><a name="_____replyseparator"></a><b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">From:</span></b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> llvm-dev [mailto:llvm-dev-bounces@lists.llvm.org]
<b>On Behalf Of </b>Shi, Steven via llvm-dev<br>
<b>Sent:</b> Tuesday, January 29, 2019 10:59 AM<br>
<b>To:</b> Peter Smith <peter.smith@linaro.org><br>
<b>Cc:</b> llvm-dev@lists.llvm.org<br>
<b>Subject:</b> Re: [llvm-dev] lld write wrong symbol value in .data section if enable -pie<o:p></o:p></span></p>
</div>
</div>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Hi Peter,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Thanks, I will try your suggestion and let you know my result.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Thanks<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Steven<o:p></o:p></span></p>
<div style="border:none;border-left:solid blue 1.5pt;padding:0in 0in 0in 4.0pt">
<div>
<div style="border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0in 0in 0in">
<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">From:</span></b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> Peter Smith [<a href="mailto:peter.smith@linaro.org">mailto:peter.smith@linaro.org</a>]
<br>
<b>Sent:</b> Tuesday, January 29, 2019 1:55 AM<br>
<b>To:</b> Shi, Steven <<a href="mailto:steven.shi@intel.com">steven.shi@intel.com</a>><br>
<b>Cc:</b> Rui Ueyama <<a href="mailto:ruiu@google.com">ruiu@google.com</a>>; <a href="mailto:llvm-dev@lists.llvm.org">
llvm-dev@lists.llvm.org</a><br>
<b>Subject:</b> Re: [llvm-dev] lld write wrong symbol value in .data section if enable -pie<o:p></o:p></span></p>
</div>
</div>
<p class="MsoNormal"><o:p> </o:p></p>
<div>
<p class="MsoNormal">Hello Steven,<o:p></o:p></p>
<div>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
<div>
<p class="MsoNormal">One difference between ld.lld and ld.bfd is that ld.lld defaults to --no-apply-dynamic-relocs (do not write the relocation addend) and ld.bfd defaults to --apply-dynamic-relocs (write the relocation addend). Can you try again with --apply-dynamic-relocs
?<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
<div>
<p class="MsoNormal">Note that for RELA relocations a dynamic loader is supposed to resolve the relocation using the Addend in the relocation, ignoring the value in the place (.data section in your case). When linking -pie it is generally assumed that you will
have a dynamic loader to resolve any relocations resulting from it so I don't think LLD is incorrect to put 0 in the .data section in this case.<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
<div>
<p class="MsoNormal">There are a couple of things I don't understand about the output though:<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal">- If the symbol we are relocating against has hidden visibility I'd expect a R_X86_64_RELATIVE relocation without a symbol for a -pie link.<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal">- I thought R_X86_64_64 wasn't a dynamic relocation? I'm not that familiar with X86 so I could be missing something glaringly obvious here.<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
<div>
<p class="MsoNormal">If --apply-dynamic-relocs doesn't work, would you consider making a small example and perhaps raise a PR? If it turns out not to be a problem we can always close it.<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
<div>
<p class="MsoNormal">Peter<o:p></o:p></p>
</div>
</div>
<p class="MsoNormal"><o:p> </o:p></p>
<div>
<div>
<p class="MsoNormal">On Mon, 28 Jan 2019 at 15:35, Shi, Steven via llvm-dev <<a href="mailto:llvm-dev@lists.llvm.org">llvm-dev@lists.llvm.org</a>> wrote:<o:p></o:p></p>
</div>
<blockquote style="border:none;border-left:solid #CCCCCC 1.0pt;padding:0in 0in 0in 6.0pt;margin-left:4.8pt;margin-top:5.0pt;margin-right:0in;margin-bottom:5.0pt">
<div>
<div>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">Hi Rui,<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">I still fail to enable the lld in my Uefi firmware build to replace ld, and I found it is related to the wrong symbol values in the .data section, which are pointed by R_X86_64_64
relocation entries. I need your advices.<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">My firmware uses a linker script
<a href="https://github.com/tianocore/edk2/blob/master/BaseTools/Scripts/GccBase.lds" target="_blank">
https://github.com/tianocore/edk2/blob/master/BaseTools/Scripts/GccBase.lds</a> to do the linking. We use position independent code with hidden visibility to inform the compiler that symbol references are never resolved at runtime. My problem is I found after
the lld linking with –pie enabled, the symbol values in .data section, which have the R_X86_64_64 relocation entries, are all 0. In other word, I found the S in below R_X86_64_64 calculation is 0.<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
<table class="MsoNormalTable" border="0" cellspacing="0" cellpadding="0" style="border-collapse:collapse">
<tbody>
<tr>
<td width="188" style="width:141.0pt;border:solid windowtext 1.0pt;padding:0in 5.4pt 0in 5.4pt">
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:9.0pt;font-family:"NimbusRomNo9L-Regu",serif;color:black">Name:</span>
<span style="font-size:9.0pt;font-family:"NimbusMonL-Regu",serif;color:black">R_X86_64_64
</span><o:p></o:p></p>
</td>
<td width="42" style="width:31.5pt;border:solid windowtext 1.0pt;border-left:none;padding:0in 5.4pt 0in 5.4pt">
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:9.0pt;font-family:"NimbusRomNo9L-Regu",serif;color:black">1
</span><o:p></o:p></p>
</td>
<td width="67" style="width:50.25pt;border:solid windowtext 1.0pt;border-left:none;padding:0in 5.4pt 0in 5.4pt">
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><i><span style="font-size:9.0pt;font-family:"NimbusRomNo9L-ReguItal",serif;color:black">word64
</span></i><o:p></o:p></p>
</td>
<td width="150" style="width:112.5pt;border:solid windowtext 1.0pt;border-left:none;padding:0in 5.4pt 0in 5.4pt">
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:9.0pt;font-family:"NimbusMonL-Regu",serif;color:black">S + A</span><o:p></o:p></p>
</td>
</tr>
</tbody>
</table>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">Below is an example to compare the lld and ld, sorry about the verbose.<o:p></o:p></p>
<p class="gmail-m-3279998374142032133msolistparagraph">1.<span style="font-size:7.0pt">
</span>Firstly, I use lld to link a HelloWorld module with -pie enabled:<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">"/home/jshi19/llvm/releaseinstall/bin/<span style="color:red">ld.lld</span>"
<span style="color:red">-pie </span>-z relro --hash-style=gnu --eh-frame-hdr -m elf_x86_64 -dynamic-linker /lib64/ld-linux-x86-64.so.2 -o /home/jshi19/wksp_efi/lgao4/edk2/Build/OvmfX64/NOOPT_CLANG38/X64/MdeModulePkg/Application/HelloWorld/HelloWorld/DEBUG/HelloWorld.dll
-u _ModuleEntryPoint -L/usr/lib/gcc/x86_64-linux-gnu/7.3.0 -L/usr/lib/gcc/x86_64-linux-gnu/7.3.0/../../../x86_64-linux-gnu -L/lib/x86_64-linux-gnu -L/lib/../lib64 -L/usr/lib/x86_64-linux-gnu -L/usr/lib/gcc/x86_64-linux-gnu/7.3.0/../../.. -L/home/jshi19/llvm/releaseinstall/bin/../lib
-L/lib -L/usr/lib -q --gc-sections -z max-page-size=0x40 --entry _ModuleEntryPoint -Map /home/jshi19/wksp_efi/lgao4/edk2/Build/OvmfX64/NOOPT_CLANG38/X64/MdeModulePkg/Application/HelloWorld/HelloWorld/DEBUG/HelloWorld.map --whole-archive -O0 -melf_x86_64 --oformat
elf64-x86-64 --start-group @/home/jshi19/wksp_efi/lgao4/edk2/Build/OvmfX64/NOOPT_CLANG38/X64/MdeModulePkg/Application/HelloWorld/HelloWorld/OUTPUT/static_library_files.lst --end-group --defsym=PECOFF_HEADER_SIZE=0x228 --script=/home/jshi19/wksp_efi/lgao4/edk2/BaseTools/Scripts/GccBase.lds<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
<p class="gmail-m-3279998374142032133msolistparagraph">2.<span style="font-size:7.0pt">
</span>Then, I check the R_X86_64_64 relocation entries in .rela.data section, and find their target offsets<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">$ readelf -r /home/jshi19/wksp_efi/lgao4/edk2/Build/OvmfX64/NOOPT_CLANG38/X64/MdeModulePkg/Application/HelloWorld/HelloWorld/DEBUG/HelloWorld.dll<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">Relocation section '.rela.data' at offset 0x5b7e8 contains 41 entries:<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> Offset Info Type Sym. Value Sym. Name + Addend<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">… …<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="color:red">000000005040
</span>00d600000001 R_X86_64_64 0000000000003130 TestFunction1 + 0<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="color:red">000000005048
</span>00d700000001 R_X86_64_64 0000000000003150 TestFunction2 + 0<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
<p class="gmail-m-3279998374142032133msolistparagraph">3.<span style="font-size:7.0pt">
</span>Next, I check the symbol values in .data section which are targeted by above R_X86_64_64 relocatons<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">$ readelf -x2 HelloWorld.dll <o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">Hex dump of section '.data':<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">NOTE: This section has relocations against it, but these have NOT been applied to this dump.<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">… …<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> 0x00005030 00000000 00000000 00000000 00000000 ................<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">
<span style="color:red">0x00005040 00000000 00000000 00000000 00000000 </span>................<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> 0x00005050 4ebe7903 06d77d43 b037edb8 2fb772a4 N.y...}C.7../.r.<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> 0x00005060 00000000 00000000 00000000 00000000 ................<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">… …<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">You can see the offset 0x5040 and 0x5048 symbol value are all 0, which is not correct.<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">But if I remove the -pie option in the above step 1 lld link command, the 0x5040 and 0x5048 symbol values are correct.<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">$ readelf -x2 HelloWorld.dll <o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">Hex dump of section '.data':<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">NOTE: This section has relocations against it, but these have NOT been applied to this dump.<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">… …<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> 0x00005030 04420000 00000000 00000000 00000000 .B..............<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="color:red"> 0x00005040 30310000 00000000 50310000 00000000 01......P1......</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> 0x00005050 4ebe7903 06d77d43 b037edb8 2fb772a4 N.y...}C.7../.r.<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> 0x00005060 00000000 00000000 00000000 00000000 ................<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">… …<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">And if I replace lld with ld but still use exact same link options with –pie enabled, the R_X86_64_64 symbol values are correct.<o:p></o:p></p>
<p class="gmail-m-3279998374142032133msolistparagraph">1.<span style="font-size:7.0pt">
</span>Link again with ld and same link options:<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="color:red">ld -pie
</span>-z relro --hash-style=gnu --eh-frame-hdr -m elf_x86_64 -dynamic-linker /lib64/ld-linux-x86-64.so.2 -o /home/jshi19/wksp_efi/lgao4/edk2/Build/OvmfX64/NOOPT_CLANG38/X64/MdeModulePkg/Application/HelloWorld/HelloWorld/DEBUG/HelloWorld.dll -u _ModuleEntryPoint
-L/usr/lib/gcc/x86_64-linux-gnu/7.3.0 -L/usr/lib/gcc/x86_64-linux-gnu/7.3.0/../../../x86_64-linux-gnu -L/lib/x86_64-linux-gnu -L/lib/../lib64 -L/usr/lib/x86_64-linux-gnu -L/usr/lib/gcc/x86_64-linux-gnu/7.3.0/../../.. -L/home/jshi19/llvm/releaseinstall/bin/../lib
-L/lib -L/usr/lib -q --gc-sections -z max-page-size=0x40 --entry _ModuleEntryPoint -Map /home/jshi19/wksp_efi/lgao4/edk2/Build/OvmfX64/NOOPT_CLANG38/X64/MdeModulePkg/Application/HelloWorld/HelloWorld/DEBUG/HelloWorld.map --whole-archive -O0 -melf_x86_64 --oformat
elf64-x86-64 --start-group @/home/jshi19/wksp_efi/lgao4/edk2/Build/OvmfX64/NOOPT_CLANG38/X64/MdeModulePkg/Application/HelloWorld/HelloWorld/OUTPUT/static_library_files.lst --end-group --defsym=PECOFF_HEADER_SIZE=0x228 --script=/home/jshi19/wksp_efi/lgao4/edk2/BaseTools/Scripts/GccBase.lds<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
<p class="gmail-m-3279998374142032133msolistparagraph">2.<span style="font-size:7.0pt">
</span>Then, check the .rela.data section R_X86_64_64 relocation entries:<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">… …<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="color:red">000000004f40
</span>00a400000001 R_X86_64_64 0000000000003130 TestFunction1 + 0<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="color:red">000000004f48
</span>009a00000001 R_X86_64_64 0000000000003150 TestFunction2 + 0<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">… …<o:p></o:p></p>
<p class="gmail-m-3279998374142032133msolistparagraph">3.<span style="font-size:7.0pt">
</span>Check the R_X86_64_64 targeting symbol values in .data section<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">… …<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> 0x00004f30 f3410000 00000000 00000000 00000000 .A..............<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">
<span style="color:red">0x00004f40 30310000 00000000 50310000 00000000 01......P1......</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> 0x00004f50 00000000 00000000 00000000 00000000 ................<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">… …<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">You can see the offset 0x4f40 and 0x4f48 symbol value are not 0, which is correct.<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">Appreciate if you could give me some advices on how to let lld output correct symbol values when enable pie.<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">Thanks<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">Steven<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> <o:p></o:p></p>
</div>
</div>
<p class="MsoNormal">_______________________________________________<br>
LLVM Developers mailing list<br>
<a href="mailto:llvm-dev@lists.llvm.org" target="_blank">llvm-dev@lists.llvm.org</a><br>
<a href="https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev" target="_blank">https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev</a><o:p></o:p></p>
</blockquote>
</div>
</div>
</div>
</div>
</body>
</html>