[llvm] [ThinLTO] Allow importing based on a workload definition (PR #74545)

[Mircea Trofin via llvm-commits]

================
@@ -369,29 +373,238 @@ class GlobalsImporter final {
   }
 };
 
+static const char *getFailureName(FunctionImporter::ImportFailureReason Reason);
+
 /// Determine the list of imports and exports for each module.
-class ModuleImportsManager final {
+class ModuleImportsManager {
+protected:
   function_ref<bool(GlobalValue::GUID, const GlobalValueSummary *)>
       IsPrevailing;
   const ModuleSummaryIndex &Index;
   DenseMap<StringRef, FunctionImporter::ExportSetTy> *const ExportLists;
 
-public:
   ModuleImportsManager(
       function_ref<bool(GlobalValue::GUID, const GlobalValueSummary *)>
           IsPrevailing,
       const ModuleSummaryIndex &Index,
       DenseMap<StringRef, FunctionImporter::ExportSetTy> *ExportLists = nullptr)
       : IsPrevailing(IsPrevailing), Index(Index), ExportLists(ExportLists) {}
 
+public:
+  virtual ~ModuleImportsManager() = default;
+
   /// Given the list of globals defined in a module, compute the list of imports
   /// as well as the list of "exports", i.e. the list of symbols referenced from
   /// another module (that may require promotion).
-  void computeImportForModule(const GVSummaryMapTy &DefinedGVSummaries,
-                              StringRef ModName,
-                              FunctionImporter::ImportMapTy &ImportList);
+  virtual void
+  computeImportForModule(const GVSummaryMapTy &DefinedGVSummaries,
+                         StringRef ModName,
+                         FunctionImporter::ImportMapTy &ImportList);
+
+  static std::unique_ptr<ModuleImportsManager>
+  create(function_ref<bool(GlobalValue::GUID, const GlobalValueSummary *)>
+             IsPrevailing,
+         const ModuleSummaryIndex &Index,
+         DenseMap<StringRef, FunctionImporter::ExportSetTy> *ExportLists =
+             nullptr);
 };
 
+class WorkloadImportsManager : public ModuleImportsManager {
+  // Keep a module name -> defined value infos association. We use it to
----------------
mtrofin wrote:

Correct.

https://github.com/llvm/llvm-project/pull/74545