DebugInfo: Generalize LoadedObjectInfoHelper from RuntimeDyld

Make it usable by any class derived (even indirectly) from
LoadedObjectInfo by allowing a custom base class to be specified and
perfect forwarding to the ctor.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@307166 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/DebugInfo/DIContext.h

@@ -221,12 +221,28 @@ public:
     return false;
   }
 
+  // FIXME: This is untested and unused anywhere in the LLVM project, it's
+  // used/needed by Julia (an external project). It should have some coverage
+  // (at least tests, but ideally example functionality).
   /// Obtain a copy of this LoadedObjectInfo.
-  ///
-  /// The caller is responsible for deallocation once the copy is no longer required.
   virtual std::unique_ptr<LoadedObjectInfo> clone() const = 0;
 };
 
+template <typename Derived, typename Base = LoadedObjectInfo>
+struct LoadedObjectInfoHelper : Base {
+protected:
+  LoadedObjectInfoHelper(const LoadedObjectInfoHelper &) = default;
+  LoadedObjectInfoHelper() = default;
+
+public:
+  template <typename... Ts>
+  LoadedObjectInfoHelper(Ts &&... Args) : Base(std::forward<Ts>(Args)...) {}
+
+  std::unique_ptr<llvm::LoadedObjectInfo> clone() const override {
+    return llvm::make_unique<Derived>(static_cast<const Derived &>(*this));
+  }
+};
+
 } // end namespace llvm
 
 #endif // LLVM_DEBUGINFO_DICONTEXT_H

include/llvm/ExecutionEngine/RuntimeDyld.h

@@ -88,21 +88,6 @@ public:
     ObjSectionToIDMap ObjSecToIDMap;
   };
 
-  template <typename Derived> struct LoadedObjectInfoHelper : LoadedObjectInfo {
-  protected:
-    LoadedObjectInfoHelper(const LoadedObjectInfoHelper &) = default;
-    LoadedObjectInfoHelper() = default;
-
-  public:
-    LoadedObjectInfoHelper(RuntimeDyldImpl &RTDyld,
-                           LoadedObjectInfo::ObjSectionToIDMap ObjSecToIDMap)
-        : LoadedObjectInfo(RTDyld, std::move(ObjSecToIDMap)) {}
-
-    std::unique_ptr<llvm::LoadedObjectInfo> clone() const override {
-      return llvm::make_unique<Derived>(static_cast<const Derived &>(*this));
-    }
-  };
-
   /// \brief Memory Management.
   class MemoryManager {
     friend class RuntimeDyld;

lib/ExecutionEngine/RuntimeDyld/RuntimeDyldCOFF.cpp

@@ -27,9 +27,12 @@ using namespace llvm::object;
 namespace {
 
 class LoadedCOFFObjectInfo final
-    : public RuntimeDyld::LoadedObjectInfoHelper<LoadedCOFFObjectInfo> {
+    : public LoadedObjectInfoHelper<LoadedCOFFObjectInfo,
+                                    RuntimeDyld::LoadedObjectInfo> {
 public:
-  LoadedCOFFObjectInfo(RuntimeDyldImpl &RTDyld, ObjSectionToIDMap ObjSecToIDMap)
+  LoadedCOFFObjectInfo(
+      RuntimeDyldImpl &RTDyld,
+      RuntimeDyld::LoadedObjectInfo::ObjSectionToIDMap ObjSecToIDMap)
       : LoadedObjectInfoHelper(RTDyld, std::move(ObjSecToIDMap)) {}
 
   OwningBinary<ObjectFile>

lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp

@@ -123,7 +123,8 @@ void DyldELFObject<ELFT>::updateSymbolAddress(const SymbolRef &SymRef,
 }
 
 class LoadedELFObjectInfo final
-    : public RuntimeDyld::LoadedObjectInfoHelper<LoadedELFObjectInfo> {
+    : public LoadedObjectInfoHelper<LoadedELFObjectInfo,
+                                    RuntimeDyld::LoadedObjectInfo> {
 public:
   LoadedELFObjectInfo(RuntimeDyldImpl &RTDyld, ObjSectionToIDMap ObjSecToIDMap)
       : LoadedObjectInfoHelper(RTDyld, std::move(ObjSecToIDMap)) {}

lib/ExecutionEngine/RuntimeDyld/RuntimeDyldMachO.cpp

@@ -27,7 +27,8 @@ using namespace llvm::object;
 namespace {
 
 class LoadedMachOObjectInfo final
-    : public RuntimeDyld::LoadedObjectInfoHelper<LoadedMachOObjectInfo> {
+    : public LoadedObjectInfoHelper<LoadedMachOObjectInfo,
+                                    RuntimeDyld::LoadedObjectInfo> {
 public:
   LoadedMachOObjectInfo(RuntimeDyldImpl &RTDyld,
                         ObjSectionToIDMap ObjSecToIDMap)