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<p class="MsoNormal">The attached patch adds support for debugging 32-bit processes when running a 64-bit lldb on an x86_64 Linux system.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Making this work required two basic changes:<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l0 level1 lfo1"><![if !supportLists]><span style="mso-list:Ignore">1)<span style="font:7.0pt "Times New Roman"">
</span></span><![endif]>Getting lldb to report that it could debug 32-bit processes<o:p></o:p></p>
<p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l0 level1 lfo1"><![if !supportLists]><span style="mso-list:Ignore">2)<span style="font:7.0pt "Times New Roman"">
</span></span><![endif]>Changing an assumption about how ptrace works when debugging cross-platform<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">For the first change, I took a conservative approach and only enabled this for x86_64 Linux platforms. It may be that the change I made in Host.cpp could be extended to other 64-bit Linux platforms, but I’m not familiar enough with the
other platforms to know for sure.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">For the second change, the Linux ProcessMonitor class was assuming that ptrace(PTRACE_[PEEK|POKE]DATA…) would read/write a “word” based on the child process word size. However, the ptrace documentation says that the “word” size read or
written is “determined by the OS variant.” I verified experimentally that when ptracing a 32-bit child from a 64-bit parent a 64-bit word is read or written.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">This patch also modifies ArchSpec.h to recognize that “unknown” indicates an unspecified vendor choice. Whether or not this comes into play seems to depend on how you build lldb.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">-Andy<o:p></o:p></p>
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