From e61652a38427b65206856f3ddc1cd55b42ad7dfd Mon Sep 17 00:00:00 2001 From: Pirama Arumuga Nainar Date: Thu, 8 Nov 2018 20:10:07 +0000 Subject: [LTO] Drop non-prevailing definitions only if linkage is not local or appending Summary: This fixes PR 37422 In ELF, non-weak symbols can also be non-prevailing. In this particular PR, the __llvm_profile_* symbols are non-prevailing but weren't getting dropped - causing multiply-defined errors with lld. Also add a test, strong_non_prevailing.ll, to ensure that multiple copies of a strong symbol are dropped. To fix the test regressions exposed by this fix, - do not mark prevailing copies for symbols with 'appending' linkage. There's no one prevailing copy for such symbols. - fix the prevailing version in dead-strip-fulllto.ll - explicitly pass exported symbols to llvm-lto in fumcimport.ll and funcimport_var.ll Reviewers: tejohnson, pcc Subscribers: mehdi_amini, inglorion, eraman, steven_wu, dexonsmith, dang, srhines, llvm-commits Differential Revision: https://reviews.llvm.org/D54125 llvm-svn: 346436 --- llvm/lib/Transforms/IPO/FunctionImport.cpp | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) (limited to 'llvm/lib/Transforms/IPO/FunctionImport.cpp') diff --git a/llvm/lib/Transforms/IPO/FunctionImport.cpp b/llvm/lib/Transforms/IPO/FunctionImport.cpp index 31531beea5e..1196dd0099b 100644 --- a/llvm/lib/Transforms/IPO/FunctionImport.cpp +++ b/llvm/lib/Transforms/IPO/FunctionImport.cpp @@ -897,8 +897,8 @@ bool llvm::convertToDeclaration(GlobalValue &GV) { return true; } -/// Fixup WeakForLinker linkages in \p TheModule based on summary analysis. -void llvm::thinLTOResolveWeakForLinkerModule( +/// Fixup prevailing symbol linkages in \p TheModule based on summary analysis. +void llvm::thinLTOResolvePrevailingInModule( Module &TheModule, const GVSummaryMapTy &DefinedGlobals) { auto updateLinkage = [&](GlobalValue &GV) { // See if the global summary analysis computed a new resolved linkage. @@ -915,13 +915,15 @@ void llvm::thinLTOResolveWeakForLinkerModule( // as we need access to the resolution vectors for each input file in // order to find which symbols have been redefined. // We may consider reorganizing this code and moving the linkage recording - // somewhere else, e.g. in thinLTOResolveWeakForLinkerInIndex. + // somewhere else, e.g. in thinLTOResolvePrevailingInIndex. if (NewLinkage == GlobalValue::WeakAnyLinkage) { GV.setLinkage(NewLinkage); return; } - if (!GlobalValue::isWeakForLinker(GV.getLinkage())) + if (GlobalValue::isLocalLinkage(GV.getLinkage()) || + // In case it was dead and already converted to declaration. + GV.isDeclaration()) return; // Check for a non-prevailing def that has interposable linkage // (e.g. non-odr weak or linkonce). In that case we can't simply @@ -932,7 +934,7 @@ void llvm::thinLTOResolveWeakForLinkerModule( GlobalValue::isInterposableLinkage(GV.getLinkage())) { if (!convertToDeclaration(GV)) // FIXME: Change this to collect replaced GVs and later erase - // them from the parent module once thinLTOResolveWeakForLinkerGUID is + // them from the parent module once thinLTOResolvePrevailingGUID is // changed to enable this for aliases. llvm_unreachable("Expected GV to be converted"); } else { -- cgit v1.2.3