From 7e7b6700743285c0af506ac6299ddf82ebd434b9 Mon Sep 17 00:00:00 2001 From: Dimitry Andric Date: Fri, 6 Jan 2017 20:13:21 +0000 Subject: Vendor import of llvm trunk r291274: https://llvm.org/svn/llvm-project/llvm/trunk@291274 --- lib/LTO/LTO.cpp | 41 ++++++++++++++++++++++++++++++++++----- lib/LTO/ThinLTOCodeGenerator.cpp | 42 +++++++++++++++++++++++++++------------- 2 files changed, 65 insertions(+), 18 deletions(-) (limited to 'lib/LTO') diff --git a/lib/LTO/LTO.cpp b/lib/LTO/LTO.cpp index 42b3a344352b..e3e2f9f806c8 100644 --- a/lib/LTO/LTO.cpp +++ b/lib/LTO/LTO.cpp @@ -337,12 +337,21 @@ void LTO::addSymbolToGlobalRes(SmallPtrSet &Used, if (Res.Prevailing) GlobalRes.IRName = GV->getName(); } + // Set the partition to external if we know it is used elsewhere, e.g. + // it is visible to a regular object, is referenced from llvm.compiler_used, + // or was already recorded as being referenced from a different partition. if (Res.VisibleToRegularObj || (GV && Used.count(GV)) || (GlobalRes.Partition != GlobalResolution::Unknown && - GlobalRes.Partition != Partition)) + GlobalRes.Partition != Partition)) { GlobalRes.Partition = GlobalResolution::External; - else + } else + // First recorded reference, save the current partition. GlobalRes.Partition = Partition; + + // Flag as visible outside of ThinLTO if visible from a regular object or + // if this is a reference in the regular LTO partition. + GlobalRes.VisibleOutsideThinLTO |= + (Res.VisibleToRegularObj || (Partition == GlobalResolution::RegularLTO)); } static void writeToResolutionFile(raw_ostream &OS, InputFile *Input, @@ -848,6 +857,19 @@ Error LTO::runThinLTO(AddStreamFn AddStream, NativeObjectCache Cache, if (!ModuleToDefinedGVSummaries.count(Mod.first)) ModuleToDefinedGVSummaries.try_emplace(Mod.first); + // Compute "dead" symbols, we don't want to import/export these! + DenseSet GUIDPreservedSymbols; + for (auto &Res : GlobalResolutions) { + if (Res.second.VisibleOutsideThinLTO && + // IRName will be defined if we have seen the prevailing copy of + // this value. If not, no need to preserve any ThinLTO copies. + !Res.second.IRName.empty()) + GUIDPreservedSymbols.insert(GlobalValue::getGUID(Res.second.IRName)); + } + + auto DeadSymbols = + computeDeadSymbols(ThinLTO.CombinedIndex, GUIDPreservedSymbols); + StringMap ImportLists( ThinLTO.ModuleMap.size()); StringMap ExportLists( @@ -856,12 +878,21 @@ Error LTO::runThinLTO(AddStreamFn AddStream, NativeObjectCache Cache, if (Conf.OptLevel > 0) { ComputeCrossModuleImport(ThinLTO.CombinedIndex, ModuleToDefinedGVSummaries, - ImportLists, ExportLists); + ImportLists, ExportLists, &DeadSymbols); std::set ExportedGUIDs; for (auto &Res : GlobalResolutions) { - if (!Res.second.IRName.empty() && - Res.second.Partition == GlobalResolution::External) + // First check if the symbol was flagged as having external references. + if (Res.second.Partition != GlobalResolution::External) + continue; + // IRName will be defined if we have seen the prevailing copy of + // this value. If not, no need to mark as exported from a ThinLTO + // partition (and we can't get the GUID). + if (Res.second.IRName.empty()) + continue; + auto GUID = GlobalValue::getGUID(Res.second.IRName); + // Mark exported unless index-based analysis determined it to be dead. + if (!DeadSymbols.count(GUID)) ExportedGUIDs.insert(GlobalValue::getGUID(Res.second.IRName)); } diff --git a/lib/LTO/ThinLTOCodeGenerator.cpp b/lib/LTO/ThinLTOCodeGenerator.cpp index 880dc3dfae98..66ffe6db29d6 100644 --- a/lib/LTO/ThinLTOCodeGenerator.cpp +++ b/lib/LTO/ThinLTOCodeGenerator.cpp @@ -581,11 +581,18 @@ void ThinLTOCodeGenerator::promote(Module &TheModule, StringMap ModuleToDefinedGVSummaries; Index.collectDefinedGVSummariesPerModule(ModuleToDefinedGVSummaries); + // Convert the preserved symbols set from string to GUID + auto GUIDPreservedSymbols = computeGUIDPreservedSymbols( + PreservedSymbols, Triple(TheModule.getTargetTriple())); + + // Compute "dead" symbols, we don't want to import/export these! + auto DeadSymbols = computeDeadSymbols(Index, GUIDPreservedSymbols); + // Generate import/export list StringMap ImportLists(ModuleCount); StringMap ExportLists(ModuleCount); ComputeCrossModuleImport(Index, ModuleToDefinedGVSummaries, ImportLists, - ExportLists); + ExportLists, &DeadSymbols); // Resolve LinkOnce/Weak symbols. StringMap> ResolvedODR; @@ -594,10 +601,6 @@ void ThinLTOCodeGenerator::promote(Module &TheModule, thinLTOResolveWeakForLinkerModule( TheModule, ModuleToDefinedGVSummaries[ModuleIdentifier]); - // Convert the preserved symbols set from string to GUID - auto GUIDPreservedSymbols = computeGUIDPreservedSymbols( - PreservedSymbols, Triple(TheModule.getTargetTriple())); - // Promote the exported values in the index, so that they are promoted // in the module. auto isExported = [&](StringRef ModuleIdentifier, GlobalValue::GUID GUID) { @@ -623,11 +626,18 @@ void ThinLTOCodeGenerator::crossModuleImport(Module &TheModule, StringMap ModuleToDefinedGVSummaries(ModuleCount); Index.collectDefinedGVSummariesPerModule(ModuleToDefinedGVSummaries); + // Convert the preserved symbols set from string to GUID + auto GUIDPreservedSymbols = computeGUIDPreservedSymbols( + PreservedSymbols, Triple(TheModule.getTargetTriple())); + + // Compute "dead" symbols, we don't want to import/export these! + auto DeadSymbols = computeDeadSymbols(Index, GUIDPreservedSymbols); + // Generate import/export list StringMap ImportLists(ModuleCount); StringMap ExportLists(ModuleCount); ComputeCrossModuleImport(Index, ModuleToDefinedGVSummaries, ImportLists, - ExportLists); + ExportLists, &DeadSymbols); auto &ImportList = ImportLists[TheModule.getModuleIdentifier()]; crossImportIntoModule(TheModule, Index, ModuleMap, ImportList); @@ -697,11 +707,14 @@ void ThinLTOCodeGenerator::internalize(Module &TheModule, StringMap ModuleToDefinedGVSummaries(ModuleCount); Index.collectDefinedGVSummariesPerModule(ModuleToDefinedGVSummaries); + // Compute "dead" symbols, we don't want to import/export these! + auto DeadSymbols = computeDeadSymbols(Index, GUIDPreservedSymbols); + // Generate import/export list StringMap ImportLists(ModuleCount); StringMap ExportLists(ModuleCount); ComputeCrossModuleImport(Index, ModuleToDefinedGVSummaries, ImportLists, - ExportLists); + ExportLists, &DeadSymbols); auto &ExportList = ExportLists[ModuleIdentifier]; // Be friendly and don't nuke totally the module when the client didn't @@ -836,17 +849,20 @@ void ThinLTOCodeGenerator::run() { StringMap ModuleToDefinedGVSummaries(ModuleCount); Index->collectDefinedGVSummariesPerModule(ModuleToDefinedGVSummaries); + // Convert the preserved symbols set from string to GUID, this is needed for + // computing the caching hash and the internalization. + auto GUIDPreservedSymbols = + computeGUIDPreservedSymbols(PreservedSymbols, TMBuilder.TheTriple); + + // Compute "dead" symbols, we don't want to import/export these! + auto DeadSymbols = computeDeadSymbols(*Index, GUIDPreservedSymbols); + // Collect the import/export lists for all modules from the call-graph in the // combined index. StringMap ImportLists(ModuleCount); StringMap ExportLists(ModuleCount); ComputeCrossModuleImport(*Index, ModuleToDefinedGVSummaries, ImportLists, - ExportLists); - - // Convert the preserved symbols set from string to GUID, this is needed for - // computing the caching hash and the internalization. - auto GUIDPreservedSymbols = - computeGUIDPreservedSymbols(PreservedSymbols, TMBuilder.TheTriple); + ExportLists, &DeadSymbols); // We use a std::map here to be able to have a defined ordering when // producing a hash for the cache entry. -- cgit v1.3