Core/Game: Fix the clang build when building shared libraries

* Hackfix to solve an unresolved issue in clang that the visibility
  flag is ignored in some explicit template specializations.
* See https://llvm.org/bugs/show_bug.cgi?id=24815
* See https://llvm.org/bugs/show_bug.cgi?id=23667

2 files changed, 30 insertions, 16 deletions

diff --git a/src/server/game/Achievements/AchievementMgr.cpp b/src/server/game/Achievements/AchievementMgr.cpp
index f1801100b25..219745e0444 100644
--- a/src/server/game/Achievements/AchievementMgr.cpp
+++ b/src/server/game/Achievements/AchievementMgr.cpp
@@ -488,13 +488,7 @@ void AchievementMgr<Guild>::ResetAchievementCriteria(AchievementCriteriaTypes /*
     // Not needed
 }
 
-template<class T>
-void AchievementMgr<T>::DeleteFromDB(ObjectGuid /*guid*/)
-{
-}
-
-template<>
-void AchievementMgr<Player>::DeleteFromDB(ObjectGuid guid)
+void DeletePlayerAchievementsFromDB(ObjectGuid guid)
 {
     SQLTransaction trans = CharacterDatabase.BeginTransaction();
 
@@ -509,8 +503,7 @@ void AchievementMgr<Player>::DeleteFromDB(ObjectGuid guid)
     CharacterDatabase.CommitTransaction(trans);
 }
 
-template<>
-void AchievementMgr<Guild>::DeleteFromDB(ObjectGuid guid)
+void DeleteGuildAchievementsFromDB(ObjectGuid guid)
 {
     SQLTransaction trans = CharacterDatabase.BeginTransaction();
 
@@ -525,16 +518,11 @@ void AchievementMgr<Guild>::DeleteFromDB(ObjectGuid guid)
     CharacterDatabase.CommitTransaction(trans);
 }
 
-template TRINITY_GAME_API
-void AchievementMgr<Player>::DeleteFromDB(ObjectGuid /*guid*/);
-
-template TRINITY_GAME_API
-void AchievementMgr<Guild>::DeleteFromDB(ObjectGuid /*guid*/);
-
 template<class T>
 void AchievementMgr<T>::SaveToDB(SQLTransaction& /*trans*/)
 {
 }
+
 template<>
 void AchievementMgr<Player>::SaveToDB(SQLTransaction& trans)
 {
diff --git a/src/server/game/Achievements/AchievementMgr.h b/src/server/game/Achievements/AchievementMgr.h
index 2d4aef490c4..678aa0bcc93 100644
--- a/src/server/game/Achievements/AchievementMgr.h
+++ b/src/server/game/Achievements/AchievementMgr.h
@@ -284,15 +284,41 @@ enum ProgressType
     PROGRESS_HIGHEST
 };
 
+// Hackfix to solve an unresolved issue in clang that the visibility
+// flag is ignored in some explicit template specializations,
+// which prevents clang from exporting the `DeleteFromDB` symbol.
+// https://llvm.org/bugs/show_bug.cgi?id=24815
+// https://llvm.org/bugs/show_bug.cgi?id=23667
+TC_GAME_API void DeletePlayerAchievementsFromDB(ObjectGuid guid);
+TC_GAME_API void DeleteGuildAchievementsFromDB(ObjectGuid guid);
+
+template<typename T>
+struct AchievementMgrDeleterBase;
+
+template<>
+struct AchievementMgrDeleterBase<Player>
+{
+    static void DeleteFromDB(ObjectGuid lowguid) { DeletePlayerAchievementsFromDB(lowguid); }
+};
+
+template<>
+struct AchievementMgrDeleterBase<Guild>
+{
+    static void DeleteFromDB(ObjectGuid lowguid) { DeleteGuildAchievementsFromDB(lowguid); }
+};
+
 template<class T>
 class TC_GAME_API AchievementMgr
+    : public AchievementMgrDeleterBase<T>
 {
     public:
         AchievementMgr(T* owner);
         ~AchievementMgr();
 
         void Reset();
-        static void DeleteFromDB(ObjectGuid lowguid);
+
+        using AchievementMgrDeleterBase<T>::DeleteFromDB;
+
         void LoadFromDB(PreparedQueryResult achievementResult, PreparedQueryResult criteriaResult);
         void SaveToDB(SQLTransaction& trans);
         void ResetAchievementCriteria(AchievementCriteriaTypes type, uint64 miscValue1 = 0, uint64 miscValue2 = 0, bool evenIfCriteriaComplete = false);