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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link="#0563C1" vlink="#954F72"><div class=WordSection1><p class=MsoNormal>Hi, <o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>After 18f201b4db339145af8f340196943ef57b9c8d9f from Rafael was merged in, we are experiencing <o:p></o:p></p><p class=MsoNormal>unreferenced symbol in several LTO programs. I analyzed the problem and find because 18f201 patch <o:p></o:p></p><p class=MsoNormal>tries to discard the aliasee by renaming it. However, it will create a problem<o:p></o:p></p><p class=MsoNormal>If the renaming happens for external functions, where non byte code may reference to the original<o:p></o:p></p><p class=MsoNormal>name and cause unreferenced symbol at the end.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>So, we have to perform forceRenaming like before without 18f201 for those symbols in ShouldLink.<o:p></o:p></p><p class=MsoNormal>Like this to force those global symbols which may expose to other module to be the original name.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>diff --git a/lib/Linker/IRMover.cpp b/lib/Linker/IRMover.cpp<o:p></o:p></p><p class=MsoNormal>index 16de0ec..68c3346 100644<o:p></o:p></p><p class=MsoNormal>--- a/lib/Linker/IRMover.cpp<o:p></o:p></p><p class=MsoNormal>+++ b/lib/Linker/IRMover.cpp<o:p></o:p></p><p class=MsoNormal>@@ -1077,7 +1077,7 @@ Constant *IRLinker::linkGlobalValueProto(GlobalValue *SGV, bool ForAlias) {<o:p></o:p></p><p class=MsoNormal> return nullptr;<o:p></o:p></p><p class=MsoNormal> <o:p></o:p></p><p class=MsoNormal> NewGV = copyGlobalValueProto(SGV, ShouldLink);<o:p></o:p></p><p class=MsoNormal>- if (!ForAlias)<o:p></o:p></p><p class=MsoNormal>+ if (ShouldLink || !ForAlias)<o:p></o:p></p><p class=MsoNormal> forceRenaming(NewGV, SGV->getName());<o:p></o:p></p><p class=MsoNormal> }<o:p></o:p></p><p class=MsoNormal> if (ShouldLink || ForAlias) {<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Please review.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Thanks,<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Yin <o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><o:p> </o:p></p></div></body></html>