(NFC) Track global summary liveness in GVFlags.

Replace GVFlags::LiveRoot with GVFlags::Live and use that instead of
all the DeadSymbols sets. This is refactoring in order to make
liveness information available in the RegularLTO pipeline.

llvm-svn: 304466

2 files changed, 22 insertions, 12 deletions

diff --git a/llvm/lib/LTO/LTO.cpp b/llvm/lib/LTO/LTO.cpp
index 9efc095f9fc..b8698c8a4f0 100644
--- a/llvm/lib/LTO/LTO.cpp
+++ b/llvm/lib/LTO/LTO.cpp
@@ -930,6 +930,17 @@ ThinBackend lto::createWriteIndexesThinBackend(std::string OldPrefix,
   };
 }
 
+static bool IsLiveByGUID(const ModuleSummaryIndex &Index,
+                         GlobalValue::GUID GUID) {
+  auto VI = Index.getValueInfo(GUID);
+  if (!VI)
+    return false;
+  for (auto &I : VI.getSummaryList())
+    if (Index.isGlobalValueLive(I.get()))
+      return true;
+  return false;
+}
+
 Error LTO::runThinLTO(AddStreamFn AddStream, NativeObjectCache Cache,
                       bool HasRegularLTO) {
   if (ThinLTO.ModuleMap.empty())
@@ -973,11 +984,10 @@ Error LTO::runThinLTO(AddStreamFn AddStream, NativeObjectCache Cache,
             GlobalValue::dropLLVMManglingEscape(Res.second.IRName)));
     }
 
-    auto DeadSymbols =
-        computeDeadSymbols(ThinLTO.CombinedIndex, GUIDPreservedSymbols);
+    computeDeadSymbols(ThinLTO.CombinedIndex, GUIDPreservedSymbols);
 
     ComputeCrossModuleImport(ThinLTO.CombinedIndex, ModuleToDefinedGVSummaries,
-                             ImportLists, ExportLists, &DeadSymbols);
+                             ImportLists, ExportLists);
 
     std::set<GlobalValue::GUID> ExportedGUIDs;
     for (auto &Res : GlobalResolutions) {
@@ -992,7 +1002,7 @@ Error LTO::runThinLTO(AddStreamFn AddStream, NativeObjectCache Cache,
       auto GUID = GlobalValue::getGUID(
           GlobalValue::dropLLVMManglingEscape(Res.second.IRName));
       // Mark exported unless index-based analysis determined it to be dead.
-      if (!DeadSymbols.count(GUID))
+      if (IsLiveByGUID(ThinLTO.CombinedIndex, GUID))
         ExportedGUIDs.insert(GUID);
     }
 
diff --git a/llvm/lib/LTO/ThinLTOCodeGenerator.cpp b/llvm/lib/LTO/ThinLTOCodeGenerator.cpp
index ca3fc60f950..6b221a347c1 100644
--- a/llvm/lib/LTO/ThinLTOCodeGenerator.cpp
+++ b/llvm/lib/LTO/ThinLTOCodeGenerator.cpp
@@ -628,13 +628,13 @@ void ThinLTOCodeGenerator::promote(Module &TheModule,
       PreservedSymbols, Triple(TheModule.getTargetTriple()));
 
   // Compute "dead" symbols, we don't want to import/export these!
-  auto DeadSymbols = computeDeadSymbols(Index, GUIDPreservedSymbols);
+  computeDeadSymbols(Index, GUIDPreservedSymbols);
 
   // Generate import/export list
   StringMap<FunctionImporter::ImportMapTy> ImportLists(ModuleCount);
   StringMap<FunctionImporter::ExportSetTy> ExportLists(ModuleCount);
   ComputeCrossModuleImport(Index, ModuleToDefinedGVSummaries, ImportLists,
-                           ExportLists, &DeadSymbols);
+                           ExportLists);
 
   // Resolve LinkOnce/Weak symbols.
   StringMap<std::map<GlobalValue::GUID, GlobalValue::LinkageTypes>> ResolvedODR;
@@ -673,13 +673,13 @@ void ThinLTOCodeGenerator::crossModuleImport(Module &TheModule,
       PreservedSymbols, Triple(TheModule.getTargetTriple()));
 
   // Compute "dead" symbols, we don't want to import/export these!
-  auto DeadSymbols = computeDeadSymbols(Index, GUIDPreservedSymbols);
+  computeDeadSymbols(Index, GUIDPreservedSymbols);
 
   // Generate import/export list
   StringMap<FunctionImporter::ImportMapTy> ImportLists(ModuleCount);
   StringMap<FunctionImporter::ExportSetTy> ExportLists(ModuleCount);
   ComputeCrossModuleImport(Index, ModuleToDefinedGVSummaries, ImportLists,
-                           ExportLists, &DeadSymbols);
+                           ExportLists);
   auto &ImportList = ImportLists[TheModule.getModuleIdentifier()];
 
   crossImportIntoModule(TheModule, Index, ModuleMap, ImportList);
@@ -750,13 +750,13 @@ void ThinLTOCodeGenerator::internalize(Module &TheModule,
   Index.collectDefinedGVSummariesPerModule(ModuleToDefinedGVSummaries);
 
   // Compute "dead" symbols, we don't want to import/export these!
-  auto DeadSymbols = computeDeadSymbols(Index, GUIDPreservedSymbols);
+  computeDeadSymbols(Index, GUIDPreservedSymbols);
 
   // Generate import/export list
   StringMap<FunctionImporter::ImportMapTy> ImportLists(ModuleCount);
   StringMap<FunctionImporter::ExportSetTy> ExportLists(ModuleCount);
   ComputeCrossModuleImport(Index, ModuleToDefinedGVSummaries, ImportLists,
-                           ExportLists, &DeadSymbols);
+                           ExportLists);
   auto &ExportList = ExportLists[ModuleIdentifier];
 
   // Be friendly and don't nuke totally the module when the client didn't
@@ -902,14 +902,14 @@ void ThinLTOCodeGenerator::run() {
       computeGUIDPreservedSymbols(PreservedSymbols, TMBuilder.TheTriple);
 
   // Compute "dead" symbols, we don't want to import/export these!
-  auto DeadSymbols = computeDeadSymbols(*Index, GUIDPreservedSymbols);
+  computeDeadSymbols(*Index, GUIDPreservedSymbols);
 
   // Collect the import/export lists for all modules from the call-graph in the
   // combined index.
   StringMap<FunctionImporter::ImportMapTy> ImportLists(ModuleCount);
   StringMap<FunctionImporter::ExportSetTy> ExportLists(ModuleCount);
   ComputeCrossModuleImport(*Index, ModuleToDefinedGVSummaries, ImportLists,
-                           ExportLists, &DeadSymbols);
+                           ExportLists);
 
   // We use a std::map here to be able to have a defined ordering when
   // producing a hash for the cache entry.