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<p class="MsoNormal"><span style="font-size:11.0pt">I've come across an email thread from 2018 regarding xray support for shared libraries. Is there a current status on this effort?<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">If this is not in active development, has there been any analysis on the effort required to add such support?<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">I have experimented with clang-12 and see that shared library functions are still not patched automatically via patch_premain.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">I have not yet looked at any APIs that might allow me to pass in a shared-library-specific table of addresses to patch.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">Similarly, it is unclear how function ids should be adjusted (if necessary) to be globally unique across shared objects.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">I'm not even sure what kind of APIs would be needed.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">Should patch/unpatch be global in nature, or should we be able to target a specific shared library (or set of shared libraries)?<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">I do see an API to patch/unpatch an individual function, but it is unclear if that would actually work against a function in a shared library due to the single XrayInstrMap involved.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">Should APIs take such a map as a parameter? Should a new dynamic XrayInstrMap be computed with all preloaded shared libraries?<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">How should dlopen'd libraries be handled?<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">I also note that even with -fxray-instrument, the shared library does not automatically get the xray support functions from compiler-rt.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">That has implications for dlopen'd libraries without an xray-enabled primary elf object.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">For example, trying to get statistics from an xray-instrumented shared library loaded from python.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">I'm guessing this is just the tip of the iceberg, and am hoping there is already a design, or perhaps some discussion about the issues involved with supporting shared libraries.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">Ideally, someone would come back and say it is already being worked, and will be available in release X !<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">Where might I find information related to this topic?<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><a href="https://llvm.org/docs/XRay.html">https://llvm.org/docs/XRay.html</a> mentions a number of ongoing efforts for expanding the toolset, but doesn't link to them.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><a href="https://llvm.org/docs/XRayExample.html">https://llvm.org/docs/XRayExample.html</a> has some Next Steps, but doesn't mention shared libraries.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">Is there another wiki that goes into more detail?<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
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