[PATCH] D73698: [ThinLTO] Import globals recursively

[Eugene Leviant via Phabricator via llvm-commits]

evgeny777 updated this revision to Diff 242918.
evgeny777 added a comment.

Rebased


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D73698/new/

https://reviews.llvm.org/D73698

Files:
  llvm/lib/Transforms/IPO/FunctionImport.cpp
  llvm/test/ThinLTO/X86/import-constant.ll


Index: llvm/test/ThinLTO/X86/import-constant.ll
===================================================================
--- llvm/test/ThinLTO/X86/import-constant.ll
+++ llvm/test/ThinLTO/X86/import-constant.ll
@@ -20,7 +20,7 @@
 ; @outer is a write-only variable, so it's been converted to zeroinitializer.
 ; IMPORT:      @outer = internal local_unnamed_addr global %struct.Q zeroinitializer
 ; IMPORT-NEXT: @_ZL3Obj.llvm.{{.*}} =  available_externally hidden constant %struct.S { i32 4, i32 8, i32* @val }
-; IMPORT-NEXT: @val = external dso_local global i32
+; IMPORT-NEXT: @val = available_externally dso_local global i32 42
 
 ; OPT: @outer = internal unnamed_addr global %struct.Q zeroinitializer
 
Index: llvm/lib/Transforms/IPO/FunctionImport.cpp
===================================================================
--- llvm/lib/Transforms/IPO/FunctionImport.cpp
+++ llvm/lib/Transforms/IPO/FunctionImport.cpp
@@ -261,8 +261,8 @@
 
 namespace {
 
-using EdgeInfo = std::tuple<const FunctionSummary *, unsigned /* Threshold */,
-                            GlobalValue::GUID>;
+using EdgeInfo =
+    std::tuple<const GlobalValueSummary *, unsigned /* Threshold */>;
 
 } // anonymous namespace
 
@@ -282,8 +282,9 @@
 }
 
 static void computeImportForReferencedGlobals(
-    const FunctionSummary &Summary, const ModuleSummaryIndex &Index,
+    const GlobalValueSummary &Summary, const ModuleSummaryIndex &Index,
     const GVSummaryMapTy &DefinedGVSummaries,
+    SmallVectorImpl<EdgeInfo> &Worklist,
     FunctionImporter::ImportMapTy &ImportList,
     StringMap<FunctionImporter::ExportSetTy> *ExportLists) {
   for (auto &VI : Summary.refs()) {
@@ -321,6 +322,11 @@
         // which is more efficient than adding them here.
         if (ExportLists)
           (*ExportLists)[RefSummary->modulePath()].insert(VI);
+
+        // If variable is not writeonly we attempt to recursively analyze
+        // its references in order to import referenced constants.
+        if (!Index.isWriteOnly(cast<GlobalVarSummary>(RefSummary.get())))
+          Worklist.emplace_back(RefSummary.get(), 0);
         break;
       }
   }
@@ -360,7 +366,7 @@
     StringMap<FunctionImporter::ExportSetTy> *ExportLists,
     FunctionImporter::ImportThresholdsTy &ImportThresholds) {
   computeImportForReferencedGlobals(Summary, Index, DefinedGVSummaries,
-                                    ImportList, ExportLists);
+                                    Worklist, ImportList, ExportLists);
   static int ImportCount = 0;
   for (auto &Edge : Summary.calls()) {
     ValueInfo VI = Edge.first;
@@ -508,7 +514,7 @@
     ImportCount++;
 
     // Insert the newly imported function to the worklist.
-    Worklist.emplace_back(ResolvedCalleeSummary, AdjThreshold, VI.getGUID());
+    Worklist.emplace_back(ResolvedCalleeSummary, AdjThreshold);
   }
 }
 
@@ -549,13 +555,17 @@
 
   // Process the newly imported functions and add callees to the worklist.
   while (!Worklist.empty()) {
-    auto FuncInfo = Worklist.pop_back_val();
-    auto *Summary = std::get<0>(FuncInfo);
-    auto Threshold = std::get<1>(FuncInfo);
-
-    computeImportForFunction(*Summary, Index, Threshold, DefinedGVSummaries,
-                             Worklist, ImportList, ExportLists,
-                             ImportThresholds);
+    auto GVInfo = Worklist.pop_back_val();
+    auto *Summary = std::get<0>(GVInfo);
+    auto Threshold = std::get<1>(GVInfo);
+
+    if (auto *FS = dyn_cast<FunctionSummary>(Summary))
+      computeImportForFunction(*FS, Index, Threshold, DefinedGVSummaries,
+                               Worklist, ImportList, ExportLists,
+                               ImportThresholds);
+    else
+      computeImportForReferencedGlobals(*Summary, Index, DefinedGVSummaries,
+                                        Worklist, ImportList, ExportLists);
   }
 
   // Print stats about functions considered but rejected for importing


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