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<p class="MsoNormal">Want to answer my second question: in that case <span style="font-size:9.5pt;font-family:Consolas;color:black">
LLVMCDisassembler </span>will be created with <span style="font-size:9.5pt;font-family:Consolas;color:black">
m_is_valid = </span><span style="font-size:9.5pt;font-family:Consolas;color:blue">false
</span>as it should, but what can happen in create{Target}MCAsmInfo is UB nevertheless. Suppose it is not good, that’s why I created revision D41584.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><b>From:</b> lldb-dev [mailto:lldb-dev-bounces@lists.llvm.org]
<b>On Behalf Of </b>Tatyana Krasnukha via lldb-dev<br>
<b>Sent:</b> Friday, 22 December, 2017 9:06 PM<br>
<b>To:</b> lldb-dev@lists.llvm.org<br>
<b>Subject:</b> [lldb-dev] Question about LLVMCDisassembler<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Hello,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Could someone answer two questions about this code, please<o:p></o:p></p>
<p class="MsoNormal">DisassemblerLLVMC::LLVMCDisassembler::LLVMCDisassembler starting from line 897:<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">  m_reg_info_ap.reset(curr_target->createMCRegInfo(triple));<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">  m_subtarget_info_ap.reset(<o:p></o:p></p>
<p class="MsoNormal">      curr_target->createMCSubtargetInfo(triple, cpu, features_str));<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">  std::unique_ptr<llvm::MCRegisterInfo> reg_info(<o:p></o:p></p>
<p class="MsoNormal">      curr_target->createMCRegInfo(triple));<o:p></o:p></p>
<p class="MsoNormal">  m_asm_info_ap.reset(curr_target->createMCAsmInfo(*reg_info, triple));<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<ol style="margin-top:0in" start="1" type="1">
<li class="MsoNormal" style="margin-left:0in;mso-list:l1 level1 lfo3">Why it cannot reuse m_reg_info_ap  for createMCAsmInfo instead of creation reg_info again?<o:p></o:p></li><li class="MsoNormal" style="margin-left:0in;mso-list:l1 level1 lfo3">It seems that createMCRegInfo can return nullptr. Is it safe to dereference reg_info in createMCAsmInfo (line 904)?<o:p></o:p></li></ol>
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