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<p class="MsoNormal">This is reiterating a message I sent out over a week ago on llvm-dev. I’ve unsuccessfully tried to address the issue in
<a href="https://bugs.llvm.org/show_bug.cgi?id=48030">https://bugs.llvm.org/show_bug.cgi?id=48030</a> and am looking for help, as this is affecting some of our licensees. I’m reiterating the originating message below:<o:p></o:p></p>
<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">I'm looking for some help on fixing <a href="https://bugs.llvm.org/show_bug.cgi?id=48030">
PR48030</a>, which is a fairly serious issue affecting our licensees.<o:p></o:p></p>
<p class="MsoNormal">A reproducible is available in the bug report, but in a nutshell, what happens is the following:<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">2 translation units A and B have definitions for an implicitly instantiated file-level<o:p></o:p></p>
<p class="MsoNormal">TLS (thread local storage) variable, both generating the same global initializer function as part<o:p></o:p></p>
<p class="MsoNormal">of the same comdat group as one would expect. TU B also generates a wrapper for accessing the TLS variable,<o:p></o:p></p>
<p class="MsoNormal">but TU A does not, because it is not needed there.<o:p></o:p></p>
<p class="MsoNormal">The wrapper in TU B calls the initializer function to ensure initialization of the TLS variable. It does<o:p></o:p></p>
<p class="MsoNormal">so through an alias of the initializer. At linktime, however, the call to the alias (weak linkage) gets fixed
<o:p></o:p></p>
<p class="MsoNormal">up to 0 when TU A first appears on the link line, b/c the linker picks the comdat group from TU A, whereas the<o:p></o:p></p>
<p class="MsoNormal">relocation against the alias is fixed up against the discarded initializer from TU B.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I've made some feeble attempts to play around with the linkages of the entities involved, but the only<o:p></o:p></p>
<p class="MsoNormal">way I have come up with is to eliminate the alias and call the initializer directly from the wrapper.<o:p></o:p></p>
<p class="MsoNormal">This breaks other things, however, so it's not an option.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Any help would be appreciated.<o:p></o:p></p>
<p class="MsoNormal">Wolfgang Pieb<o:p></o:p></p>
<p class="MsoNormal">SN Systems/Sony Computer Entertainment<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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