1 files changed, 47 insertions, 60 deletions

diff --git a/llvm/lib/Transforms/IPO/FunctionImport.cpp b/llvm/lib/Transforms/IPO/FunctionImport.cpp
index 231487923fa..6d34ab8b0d9 100644
--- a/llvm/lib/Transforms/IPO/FunctionImport.cpp
+++ b/llvm/lib/Transforms/IPO/FunctionImport.cpp
@@ -292,8 +292,7 @@ static void computeImportForFunction(
 static void ComputeImportForModule(
     const GVSummaryMapTy &DefinedGVSummaries, const ModuleSummaryIndex &Index,
     FunctionImporter::ImportMapTy &ImportList,
-    StringMap<FunctionImporter::ExportSetTy> *ExportLists = nullptr,
-    const DenseSet<GlobalValue::GUID> *DeadSymbols = nullptr) {
+    StringMap<FunctionImporter::ExportSetTy> *ExportLists = nullptr) {
   // Worklist contains the list of function imported in this module, for which
   // we will analyse the callees and may import further down the callgraph.
   SmallVector<EdgeInfo, 128> Worklist;
@@ -301,7 +300,7 @@ static void ComputeImportForModule(
   // Populate the worklist with the import for the functions in the current
   // module
   for (auto &GVSummary : DefinedGVSummaries) {
-    if (DeadSymbols && DeadSymbols->count(GVSummary.first)) {
+    if (!Index.isGlobalValueLive(GVSummary.second)) {
       DEBUG(dbgs() << "Ignores Dead GUID: " << GVSummary.first << "\n");
       continue;
     }
@@ -344,15 +343,14 @@ void llvm::ComputeCrossModuleImport(
     const ModuleSummaryIndex &Index,
     const StringMap<GVSummaryMapTy> &ModuleToDefinedGVSummaries,
     StringMap<FunctionImporter::ImportMapTy> &ImportLists,
-    StringMap<FunctionImporter::ExportSetTy> &ExportLists,
-    const DenseSet<GlobalValue::GUID> *DeadSymbols) {
+    StringMap<FunctionImporter::ExportSetTy> &ExportLists) {
   // For each module that has function defined, compute the import/export lists.
   for (auto &DefinedGVSummaries : ModuleToDefinedGVSummaries) {
     auto &ImportList = ImportLists[DefinedGVSummaries.first()];
     DEBUG(dbgs() << "Computing import for Module '"
                  << DefinedGVSummaries.first() << "'\n");
     ComputeImportForModule(DefinedGVSummaries.second, Index, ImportList,
-                           &ExportLists, DeadSymbols);
+                           &ExportLists);
   }
 
   // When computing imports we added all GUIDs referenced by anything
@@ -414,82 +412,71 @@ void llvm::ComputeCrossModuleImportForModule(
 #endif
 }
 
-DenseSet<GlobalValue::GUID> llvm::computeDeadSymbols(
-    const ModuleSummaryIndex &Index,
+void llvm::computeDeadSymbols(
+    ModuleSummaryIndex &Index,
     const DenseSet<GlobalValue::GUID> &GUIDPreservedSymbols) {
+  assert(!Index.withGlobalValueDeadStripping());
   if (!ComputeDead)
-    return DenseSet<GlobalValue::GUID>();
+    return;
   if (GUIDPreservedSymbols.empty())
     // Don't do anything when nothing is live, this is friendly with tests.
-    return DenseSet<GlobalValue::GUID>();
-  DenseSet<ValueInfo> LiveSymbols;
+    return;
+  unsigned LiveSymbols = 0;
   SmallVector<ValueInfo, 128> Worklist;
   Worklist.reserve(GUIDPreservedSymbols.size() * 2);
   for (auto GUID : GUIDPreservedSymbols) {
     ValueInfo VI = Index.getValueInfo(GUID);
     if (!VI)
       continue;
-    DEBUG(dbgs() << "Live root: " << VI.getGUID() << "\n");
-    LiveSymbols.insert(VI);
-    Worklist.push_back(VI);
+    for (auto &S : VI.getSummaryList())
+      S->setLive(true);
   }
+
   // Add values flagged in the index as live roots to the worklist.
-  for (const auto &Entry : Index) {
-    bool IsLiveRoot = llvm::any_of(
-        Entry.second.SummaryList,
-        [&](const std::unique_ptr<llvm::GlobalValueSummary> &Summary) {
-          return Summary->liveRoot();
-        });
-    if (!IsLiveRoot)
-      continue;
-    DEBUG(dbgs() << "Live root (summary): " << Entry.first << "\n");
-    Worklist.push_back(ValueInfo(&Entry));
-  }
+  for (const auto &Entry : Index)
+    for (auto &S : Entry.second.SummaryList)
+      if (S->isLive()) {
+        DEBUG(dbgs() << "Live root: " << Entry.first << "\n");
+        Worklist.push_back(ValueInfo(&Entry));
+        ++LiveSymbols;
+        break;
+      }
+
+  // Make value live and add it to the worklist if it was not live before.
+  // FIXME: we should only make the prevailing copy live here
+  auto visit = [&](ValueInfo VI) {
+    for (auto &S : VI.getSummaryList())
+      if (S->isLive())
+        return;
+    for (auto &S : VI.getSummaryList())
+      S->setLive(true);
+    ++LiveSymbols;
+    Worklist.push_back(VI);
+  };
 
   while (!Worklist.empty()) {
     auto VI = Worklist.pop_back_val();
-
-    // FIXME: we should only make the prevailing copy live here
     for (auto &Summary : VI.getSummaryList()) {
-      for (auto Ref : Summary->refs()) {
-        if (LiveSymbols.insert(Ref).second) {
-          DEBUG(dbgs() << "Marking live (ref): " << Ref.getGUID() << "\n");
-          Worklist.push_back(Ref);
-        }
-      }
-      if (auto *FS = dyn_cast<FunctionSummary>(Summary.get())) {
-        for (auto Call : FS->calls()) {
-          if (LiveSymbols.insert(Call.first).second) {
-            DEBUG(dbgs() << "Marking live (call): " << Call.first.getGUID()
-                         << "\n");
-            Worklist.push_back(Call.first);
-          }
-        }
-      }
+      for (auto Ref : Summary->refs())
+        visit(Ref);
+      if (auto *FS = dyn_cast<FunctionSummary>(Summary.get()))
+        for (auto Call : FS->calls())
+          visit(Call.first);
       if (auto *AS = dyn_cast<AliasSummary>(Summary.get())) {
         auto AliaseeGUID = AS->getAliasee().getOriginalName();
         ValueInfo AliaseeVI = Index.getValueInfo(AliaseeGUID);
-        if (AliaseeVI && LiveSymbols.insert(AliaseeVI).second) {
-          DEBUG(dbgs() << "Marking live (alias): " << AliaseeGUID << "\n");
-          Worklist.push_back(AliaseeVI);
-        }
+        if (AliaseeVI)
+          visit(AliaseeVI);
       }
     }
   }
-  DenseSet<GlobalValue::GUID> DeadSymbols;
-  DeadSymbols.reserve(
-      std::min(Index.size(), Index.size() - LiveSymbols.size()));
-  for (auto &Entry : Index) {
-    if (!LiveSymbols.count(ValueInfo(&Entry))) {
-      DEBUG(dbgs() << "Marking dead: " << Entry.first << "\n");
-      DeadSymbols.insert(Entry.first);
-    }
-  }
-  DEBUG(dbgs() << LiveSymbols.size() << " symbols Live, and "
-               << DeadSymbols.size() << " symbols Dead \n");
-  NumDeadSymbols += DeadSymbols.size();
-  NumLiveSymbols += LiveSymbols.size();
-  return DeadSymbols;
+  Index.setWithGlobalValueDeadStripping();
+
+  unsigned DeadSymbols = Index.size() - LiveSymbols;
+  DEBUG(dbgs() << LiveSymbols << " symbols Live, and " << DeadSymbols
+               << " symbols Dead \n");
+  NumDeadSymbols += DeadSymbols;
+  NumLiveSymbols += LiveSymbols;
 }
 
 /// Compute the set of summaries needed for a ThinLTO backend compilation of