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<p class="MsoNormal"><a name="_MailEndCompose"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Hi Peter, Rui<o:p></o:p></span></a></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Thank you for the info.<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</span><b><span style="font-family:"Arial",sans-serif;color:#1F497D"><o:p></o:p></span></b></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D"><o:p> </o:p></span></p>
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<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"> Rui Ueyama [mailto:ruiu@google.com]
<br>
<b>Sent:</b> Thursday, January 24, 2019 3:02 AM<br>
<b>To:</b> Shi, Steven <steven.shi@intel.com><br>
<b>Cc:</b> llvm-dev@lists.llvm.org<br>
<b>Subject:</b> Re: Why -pie option force LLD to output shared obj file type, not executable?<o:p></o:p></span></p>
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<p class="MsoNormal">lld sets ET_DYN instead of ET_EXEC if `-pic` is specified, which is basically the same behavior except the case that Peter explained. Unfortunately, there's no way to set ET_EXEC using lld, but the "type" field is 2 byte long and at offset
16, so you can edit it using a binary editor to change it from ET_DYN to ET_EXEC (although it's super hacky).<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">If you have GNU sed, you can do with the following command to change the field value:<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">sed -E -i -e '1s/^(.{16})../\1\x2\x0/' your-executable-file<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Does that work for you?<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">On Wed, Jan 23, 2019 at 7:47 AM Shi, Steven <<a href="mailto:steven.shi@intel.com">steven.shi@intel.com</a>> wrote:<o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">Hello Rui,<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">I’m enabling the LLD in the Uefi firmware edk2 build. I meet a problem about the -pie option and cannot output the executable type obj file correctly. I need your advice.<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">The Uefi firmware executable binary is the position independent + small code mode in 64bits. So we always add the options “-Wl,-pie -mcmodel=small” in our clang build toolchain.
These options work well with binutils LD, but cannot work with LLD. I see the LLD uses the below code to force the output obj file as shared obj type if link with -pie. Is there any way to let LLD output executable type obj with -pie option? I’m OK if I have
to link twice, first output DYN and then covert to EXEC in some way. Could you give some link command examples on it?<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">lld\ELF\Writer.cpp<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:9.5pt;font-family:Consolas;color:blue">static</span><span style="font-size:9.5pt;font-family:Consolas;color:black">
</span><span style="font-size:9.5pt;font-family:Consolas;color:#2B91AF">uint16_t</span><span style="font-size:9.5pt;font-family:Consolas;color:black"> getELFType() {</span><o:p></o:p></p>
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</span><span style="font-size:9.5pt;font-family:Consolas;color:blue">if</span><span style="font-size:9.5pt;font-family:Consolas;color:black"> (Config->Pic)</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:9.5pt;font-family:Consolas;color:black">
</span><span style="font-size:9.5pt;font-family:Consolas;color:blue">return</span><span style="font-size:9.5pt;font-family:Consolas;color:black">
</span><span style="font-size:9.5pt;font-family:Consolas;color:darkslategray">ET_DYN</span><span style="font-size:9.5pt;font-family:Consolas;color:black">;</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:9.5pt;font-family:Consolas;color:black">
</span><span style="font-size:9.5pt;font-family:Consolas;color:blue">if</span><span style="font-size:9.5pt;font-family:Consolas;color:black"> (Config->Relocatable)</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:9.5pt;font-family:Consolas;color:black">
</span><span style="font-size:9.5pt;font-family:Consolas;color:blue">return</span><span style="font-size:9.5pt;font-family:Consolas;color:black">
</span><span style="font-size:9.5pt;font-family:Consolas;color:darkslategray">ET_REL</span><span style="font-size:9.5pt;font-family:Consolas;color:black">;</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:9.5pt;font-family:Consolas;color:black">
</span><span style="font-size:9.5pt;font-family:Consolas;color:blue">return</span><span style="font-size:9.5pt;font-family:Consolas;color:black">
</span><span style="font-size:9.5pt;font-family:Consolas;color:darkslategray">ET_EXEC</span><span style="font-size:9.5pt;font-family:Consolas;color:black">;</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:9.5pt;font-family:Consolas;color:black">}</span><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>
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