[ThinLTO] Import readonly vars with refs

Patch allows importing declarations of functions and variables, referenced
by the initializer of some other readonly variable.
Differential revision: https://reviews.llvm.org/D69561

1 files changed, 16 insertions, 6 deletions

diff --git a/llvm/lib/Transforms/IPO/FunctionImport.cpp b/llvm/lib/Transforms/IPO/FunctionImport.cpp
index 3f5cc078d75..afc31bff3a6 100644
--- a/llvm/lib/Transforms/IPO/FunctionImport.cpp
+++ b/llvm/lib/Transforms/IPO/FunctionImport.cpp
@@ -280,7 +280,8 @@ updateValueInfoForIndirectCalls(const ModuleSummaryIndex &Index, ValueInfo VI) {
 }
 
 static void computeImportForReferencedGlobals(
-    const FunctionSummary &Summary, const GVSummaryMapTy &DefinedGVSummaries,
+    const FunctionSummary &Summary, const ModuleSummaryIndex &Index,
+    const GVSummaryMapTy &DefinedGVSummaries,
     FunctionImporter::ImportMapTy &ImportList,
     StringMap<FunctionImporter::ExportSetTy> *ExportLists) {
   for (auto &VI : Summary.refs()) {
@@ -303,16 +304,24 @@ static void computeImportForReferencedGlobals(
              RefSummary->modulePath() != Summary.modulePath();
     };
 
+    auto MarkExported = [&](const ValueInfo &VI, const GlobalValueSummary *S) {
+      if (ExportLists)
+        (*ExportLists)[S->modulePath()].insert(VI.getGUID());
+    };
+
     for (auto &RefSummary : VI.getSummaryList())
       if (isa<GlobalVarSummary>(RefSummary.get()) &&
-          canImportGlobalVar(RefSummary.get()) &&
+          Index.canImportGlobalVar(RefSummary.get(), /* AnalyzeRefs */ true) &&
           !LocalNotInModule(RefSummary.get())) {
         auto ILI = ImportList[RefSummary->modulePath()].insert(VI.getGUID());
         // Only update stat if we haven't already imported this variable.
         if (ILI.second)
           NumImportedGlobalVarsThinLink++;
-        if (ExportLists)
-          (*ExportLists)[RefSummary->modulePath()].insert(VI.getGUID());
+        MarkExported(VI, RefSummary.get());
+        // Promote referenced functions and variables
+        for (const auto &VI : RefSummary->refs())
+          for (const auto &RefFn : VI.getSummaryList())
+            MarkExported(VI, RefFn.get());
         break;
       }
   }
@@ -351,8 +360,8 @@ static void computeImportForFunction(
     FunctionImporter::ImportMapTy &ImportList,
     StringMap<FunctionImporter::ExportSetTy> *ExportLists,
     FunctionImporter::ImportThresholdsTy &ImportThresholds) {
-  computeImportForReferencedGlobals(Summary, DefinedGVSummaries, ImportList,
-                                    ExportLists);
+  computeImportForReferencedGlobals(Summary, Index, DefinedGVSummaries,
+                                    ImportList, ExportLists);
   static int ImportCount = 0;
   for (auto &Edge : Summary.calls()) {
     ValueInfo VI = Edge.first;
@@ -864,6 +873,7 @@ void llvm::computeDeadSymbolsWithConstProp(
           GVS->setWriteOnly(false);
         }
   }
+  Index.setWithAttributePropagation();
 }
 
 /// Compute the set of summaries needed for a ThinLTO backend compilation of