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<p class="MsoNormal">Hi,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I’m writing a ‘LLVM Integrated Assembler’ for an in-house 32bits micro controller.<o:p></o:p></p>
<p class="MsoNormal">As far as now, I’ve followed the instructions from Simon Cook (Embecosm) as described in <a href="http://www.embecosm.com/appnotes/ean10/ean10-howto-llvmas-1.0.html">http://www.embecosm.com/appnotes/ean10/ean10-howto-llvmas-1.0.html</a><o:p></o:p></p>
<p class="MsoNormal">But, I don’t catch how to finalize the relocations.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">In the case of my micro controller, relocation are only used for the ‘Jump’ instruction.<o:p></o:p></p>
<p class="MsoNormal">The ‘Jump’ instruction is composed of 32 bits opcode, followed bit a 32 bits absolute jump address.<o:p></o:p></p>
<p class="MsoNormal">When parsed, this jump address is saved as an expression.<o:p></o:p></p>
<p class="MsoNormal">Later, this expression is translated into a fixup. <o:p></o:p></p>
<p class="MsoNormal">Finally, the fixup is translated into a relocation type by the GetRelocType(). (I only have one relocation type.)<o:p></o:p></p>
<p class="MsoNormal">The generated ELF file includes the relocation records. I can dump this relocation records with standard linux ‘readelf’ command.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal" style="margin-bottom:12.0pt"><span style="font-size:12.0pt;font-family:"Times New Roman","serif"">Relocation section '.rela.text' at offset 0x470 contains 2 entries:<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-bottom:12.0pt"><span style="font-size:12.0pt;font-family:"Times New Roman","serif"">Offset Info Type Sym.Value Sym. Name + Addend<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-bottom:12.0pt"><span style="font-size:12.0pt;font-family:"Times New Roman","serif"">0000024c 00000101 unrecognized: 1 00000224 Lback + 0<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-bottom:12.0pt"><span style="font-size:12.0pt;font-family:"Times New Roman","serif"">00000254 00000101 unrecognized: 1 00000224 Lback + 0<br>
<br>
<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-bottom:12.0pt">So far, so good! But the relocation type are unrecognized and the standard linux ‘ld’ command reports an error.<o:p></o:p></p>
<p class="MsoNormal" style="margin-bottom:12.0pt"><span style="font-size:12.0pt;font-family:"Times New Roman","serif"">ld: /tmp/branch.o: Relocations in generic ELF (EM: 201)<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-bottom:12.0pt"><span style="font-size:12.0pt;font-family:"Times New Roman","serif"">/tmp/branch.o: error adding symbols: File in wrong format<o:p></o:p></span></p>
<p class="MsoNormal">My understanding is that now I have to ‘open’ the GNU ‘ld’ sources files to add the relocation schema for my ‘jump’ instruction.<o:p></o:p></p>
<p class="MsoNormal">I would like to avoid modifying the GNU ‘ld’ or the LLVM linker.<o:p></o:p></p>
<p class="MsoNormal">My relocation schema is quite simple: at relocation record offset, I have to write the Sym. Value on 32 bits big endian.<o:p></o:p></p>
<p class="MsoNormal">Is there such simple relocation schema already built-in the GNU ‘ld’?<o:p></o:p></p>
<p class="MsoNormal">And how to activate it, by returning a relocation type in the GetRelocType()?<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Thanks, in advance? <span lang="FR-BE">Dominique Torette.
</span><span lang="FR-BE" style="font-size:12.0pt;font-family:"Times New Roman","serif""><br>
<br>
</span><span lang="FR-BE"><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Times New Roman","serif""><img border="0" width="536" height="49" id="_x0000_i1025" src="http://www.spacebel.be/wp-content/uploads/2011/06/image-sign-sbp.jpg" alt="http://www.spacebel.be/wp-content/uploads/2011/06/image-sign-sbp.jpg"></span><span lang="FR-BE" style="font-size:12.0pt;font-family:"Times New Roman","serif""><o:p></o:p></span></p>
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<p class="MsoNormal" align="center" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;text-align:center">
<b><span lang="FR-BE" style="font-size:10.0pt">Dominique Torette</span></b><span lang="FR-BE" style="font-size:10.0pt">
<br>
System Architect<br>
Rue des Chasseurs Ardennais - Liège Science Park - B-4031 Angleur <br>
Tel: +32 (0) 4 361 81 11 - Fax: +32 (0) 4 361 81 20 <br>
</span><span style="font-size:10.0pt"><a href="http://www.spacebel.be/"><span lang="FR-BE" style="color:blue">www.spacebel.be</span></a></span><span lang="FR-BE" style="font-size:12.0pt;font-family:"Times New Roman","serif""><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="FR-BE"><o:p> </o:p></span></p>
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