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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Hi Mike,<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">A variation of reloc-fix-32.patch was committed today by Richard Mitton.<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">I need to do something with stack-fix-32.patch. If I’m reading the documentation correctly, it appears that stack frames really do need to be 8-byte aligned
in Darwin even for 32-bit code.<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">Unfortunately, we’re using the same ABI plugin for 32-bit x86 code on Darwin and Linux and at the level where this check is performed we don’t know which we’re
looking at. As far as I know, there really isn’t a significant difference between the two scenarios, so I don’t think we’d want a totally separate ABI plug-in. I just need to see if there’s an easy way to give it a little target information when it’s created
so it can handle the special cases.<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">As for your patch, am I correct in thinking that I should ignore the history in that review? Can you explain the change to me? What values were you seeing
for sh_entsize and sh_addralign?<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">-Andy<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:"Tahoma","sans-serif"">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> Michael Sartain [mailto:mikesart@gmail.com]
<br>
<b>Sent:</b> Thursday, August 15, 2013 1:07 PM<br>
<b>To:</b> Greg Clayton; Kaylor, Andrew<br>
<b>Cc:</b> lldb-dev@cs.uiuc.edu<br>
<b>Subject:</b> Re: [lldb-dev] lldb test failures on 32bit<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">I realized Andrew's reloc-fix-32.patch & stack-fix-32.patch weren't checked in and I didn't have them. Applying both of those with my patch below allows me to step over the 32-bit printf() calls now.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Are those patches what you hope to check in at some point Andrew?<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">And please let me know if it's ok to check this in:<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><a href="http://llvm-reviews.chandlerc.com/D1189" target="_blank">http://llvm-reviews.chandlerc.com/D1189</a><o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Thanks!<o:p></o:p></p>
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<p class="MsoNormal"> -Mike<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 Thu, Aug 15, 2013 at 10:39 AM, Michael Sartain <<a href="mailto:mikesart@gmail.com" target="_blank">mikesart@gmail.com</a>> wrote:<o:p></o:p></p>
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<p class="MsoNormal">On Tue, Aug 13, 2013 at 6:22 PM, Michael Sartain <<a href="mailto:mikesart@gmail.com" target="_blank">mikesart@gmail.com</a>> wrote:<o:p></o:p></p>
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<p class="MsoNormal">Unwind info does exist for addresses in main(), and all of this works as expected in x64.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">I'll start debugging where this is failing...<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">For x86 elf files, the plt_entsize wasn't being rounded to the proper alignment - this was causing the .plt symbols to be incorrect, along with unwind info, etc. This patch fixes that:<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><a href="http://llvm-reviews.chandlerc.com/D1189" target="_blank">http://llvm-reviews.chandlerc.com/D1189</a><o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">The next problem is we're using the x64 register set, but then calling into the i386 ABI. Ie, this call:<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"> 246| addr_t pc;<o:p></o:p></p>
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<p class="MsoNormal"> 247+> if (!ReadGPRValue (eRegisterKindGeneric, LLDB_REGNUM_GENERIC_PC, pc))<o:p></o:p></p>
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<p class="MsoNormal"> 248| {<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Winds up here:<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">1092| ExecutionContext exe_ctx(m_thread.shared_from_this());<o:p></o:p></p>
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<p class="MsoNormal">1093| Process *process = exe_ctx.GetProcessPtr();<o:p></o:p></p>
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<p class="MsoNormal">1094| if (have_unwindplan_regloc == false)<o:p></o:p></p>
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<p class="MsoNormal">1095| {<o:p></o:p></p>
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<p class="MsoNormal">1096| // If a volatile register is being requested, we don't want to forward the next frame's register contents<o:p></o:p></p>
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<p class="MsoNormal">1097| // up the stack -- the register is not retrievable at this frame.<o:p></o:p></p>
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<p class="MsoNormal">1098| ABI *abi = process ? process->GetABI().get() : NULL;<o:p></o:p></p>
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<p class="MsoNormal">1099| if (abi)<o:p></o:p></p>
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<p class="MsoNormal">1100| {<o:p></o:p></p>
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<p class="MsoNormal">1101+> const RegisterInfo *reg_info = GetRegisterInfoAtIndex(lldb_regnum);<o:p></o:p></p>
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<p class="MsoNormal">1102| if (reg_info && abi->RegisterIsVolatile (reg_info))<o:p></o:p></p>
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<p class="MsoNormal">1103| {<o:p></o:p></p>
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<p class="MsoNormal">1104| UnwindLogMsg ("did not supply reg location for %d (%s) because it is volatile",<o:p></o:p></p>
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<p class="MsoNormal">1105| lldb_regnum, reg_info->name ? reg_info->name : "??");<o:p></o:p></p>
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<p class="MsoNormal">1106| return UnwindLLDB::RegisterSearchResult::eRegisterIsVolatile;<o:p></o:p></p>
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<p class="MsoNormal">1107| }<o:p></o:p></p>
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<p class="MsoNormal">1108| }<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Which calls into this function:<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">902| bool<o:p></o:p></p>
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<p class="MsoNormal">903| ABIMacOSX_i386::RegisterIsCalleeSaved (const RegisterInfo *reg_info)<o:p></o:p></p>
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<p class="MsoNormal">904| {<o:p></o:p></p>
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<p class="MsoNormal">905| if (reg_info)<o:p></o:p></p>
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<p class="MsoNormal">906| {<o:p></o:p></p>
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<p class="MsoNormal">907| // Saved registers are ebx, ebp, esi, edi, esp, eip<o:p></o:p></p>
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<p class="MsoNormal">908| const char *name = reg_info->name;<o:p></o:p></p>
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<p class="MsoNormal">909| if (name[0] == 'e')<o:p></o:p></p>
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<p class="MsoNormal">910| {<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">reg_info->name is "rip", and so ABIMacOSX_i386::RegisterIsCalleeSaved() is returning false.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">ABIMacOSX_i386.cpp looks like it does several things using register names.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif"">> Actually, RegisterContext_i386 doesn't get used in the case of a 32-bit inferior on a 64-bit host. In that scenario we use RegisterContext_x86_64 and do some mapping under
the covers for 32-bit targets.</span><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 this mean this is an issue with RegisterContext_x86_64 returning "rip" and not "eip"?<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Thanks.<o:p></o:p></p>
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<p class="MsoNormal"> -Mike<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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