Add a RAII class for saving and restoring instantiations and uses. No behavior change.

llvm-svn: 215780

clang/include/clang/Sema/Sema.h

@@ -6568,6 +6568,31 @@ public:
   /// but have not yet been performed.
   std::deque<PendingImplicitInstantiation> PendingInstantiations;
 
+  class SavePendingInstantiationsAndVTableUsesRAII {
+  public:
+    SavePendingInstantiationsAndVTableUsesRAII(Sema &S): S(S) {
+      SavedPendingInstantiations.swap(S.PendingInstantiations);
+      SavedVTableUses.swap(S.VTableUses);
+    }
+
+    ~SavePendingInstantiationsAndVTableUsesRAII() {
+      // Restore the set of pending vtables.
+      assert(S.VTableUses.empty() &&
+             "VTableUses should be empty before it is discarded.");
+      S.VTableUses.swap(SavedVTableUses);
+
+      // Restore the set of pending implicit instantiations.
+      assert(S.PendingInstantiations.empty() &&
+             "PendingInstantiations should be empty before it is discarded.");
+      S.PendingInstantiations.swap(SavedPendingInstantiations);
+    }
+
+  private:
+    Sema &S;
+    SmallVector<VTableUse, 16> SavedVTableUses;
+    std::deque<PendingImplicitInstantiation> SavedPendingInstantiations;
+  };
+
   /// \brief The queue of implicit template instantiations that are required
   /// and must be performed within the current local scope.
   ///

clang/lib/Sema/SemaTemplateInstantiateDecl.cpp

@@ -3389,13 +3389,13 @@ void Sema::InstantiateFunctionDefinition(SourceLocation PointOfInstantiation,
   // If we're performing recursive template instantiation, create our own
   // queue of pending implicit instantiations that we will instantiate later,
   // while we're still within our own instantiation context.
-  SmallVector<VTableUse, 16> SavedVTableUses;
-  std::deque<PendingImplicitInstantiation> SavedPendingInstantiations;
   SavePendingLocalImplicitInstantiationsRAII
       SavedPendingLocalImplicitInstantiations(*this);
+  std::unique_ptr<SavePendingInstantiationsAndVTableUsesRAII>
+      SavePendingInstantiationsAndVTableUses;
   if (Recursive) {
-    VTableUses.swap(SavedVTableUses);
-    PendingInstantiations.swap(SavedPendingInstantiations);
+    SavePendingInstantiationsAndVTableUses.reset(
+        new SavePendingInstantiationsAndVTableUsesRAII(*this));
   }
 
   EnterExpressionEvaluationContext EvalContext(*this,
@@ -3466,15 +3466,8 @@ void Sema::InstantiateFunctionDefinition(SourceLocation PointOfInstantiation,
     // instantiation of this template.
     PerformPendingInstantiations();
 
-    // Restore the set of pending vtables.
-    assert(VTableUses.empty() &&
-           "VTableUses should be empty before it is discarded.");
-    VTableUses.swap(SavedVTableUses);
-
-    // Restore the set of pending implicit instantiations.
-    assert(PendingInstantiations.empty() &&
-           "PendingInstantiations should be empty before it is discarded.");
-    PendingInstantiations.swap(SavedPendingInstantiations);
+    // Restore PendingInstantiations and VTableUses.
+    SavePendingInstantiationsAndVTableUses.reset();
   }
 }
 
@@ -3790,11 +3783,11 @@ void Sema::InstantiateVariableDefinition(SourceLocation PointOfInstantiation,
       // If we're performing recursive template instantiation, create our own
       // queue of pending implicit instantiations that we will instantiate
       // later, while we're still within our own instantiation context.
-      SmallVector<VTableUse, 16> SavedVTableUses;
-      std::deque<PendingImplicitInstantiation> SavedPendingInstantiations;
+      std::unique_ptr<SavePendingInstantiationsAndVTableUsesRAII>
+          SavePendingInstantiationsAndVTableUses;
       if (Recursive) {
-        VTableUses.swap(SavedVTableUses);
-        PendingInstantiations.swap(SavedPendingInstantiations);
+        SavePendingInstantiationsAndVTableUses.reset(
+            new SavePendingInstantiationsAndVTableUsesRAII(*this));
       }
 
       LocalInstantiationScope Local(*this);
@@ -3822,15 +3815,8 @@ void Sema::InstantiateVariableDefinition(SourceLocation PointOfInstantiation,
         // instantiation of this template.
         PerformPendingInstantiations();
 
-        // Restore the set of pending vtables.
-        assert(VTableUses.empty() &&
-               "VTableUses should be empty before it is discarded.");
-        VTableUses.swap(SavedVTableUses);
-
-        // Restore the set of pending implicit instantiations.
-        assert(PendingInstantiations.empty() &&
-               "PendingInstantiations should be empty before it is discarded.");
-        PendingInstantiations.swap(SavedPendingInstantiations);
+        // Restore PendingInstantiations and VTableUses.
+        SavePendingInstantiationsAndVTableUses.reset();
       }
     }
 
@@ -3914,13 +3900,13 @@ void Sema::InstantiateVariableDefinition(SourceLocation PointOfInstantiation,
   // If we're performing recursive template instantiation, create our own
   // queue of pending implicit instantiations that we will instantiate later,
   // while we're still within our own instantiation context.
-  SmallVector<VTableUse, 16> SavedVTableUses;
-  std::deque<PendingImplicitInstantiation> SavedPendingInstantiations;
   SavePendingLocalImplicitInstantiationsRAII
       SavedPendingLocalImplicitInstantiations(*this);
+  std::unique_ptr<SavePendingInstantiationsAndVTableUsesRAII>
+      SavePendingInstantiationsAndVTableUses;
   if (Recursive) {
-    VTableUses.swap(SavedVTableUses);
-    PendingInstantiations.swap(SavedPendingInstantiations);
+    SavePendingInstantiationsAndVTableUses.reset(
+        new SavePendingInstantiationsAndVTableUsesRAII(*this));
   }
 
   // Enter the scope of this instantiation. We don't use
@@ -3987,15 +3973,8 @@ void Sema::InstantiateVariableDefinition(SourceLocation PointOfInstantiation,
     // instantiation of this template.
     PerformPendingInstantiations();
 
-    // Restore the set of pending vtables.
-    assert(VTableUses.empty() &&
-           "VTableUses should be empty before it is discarded.");
-    VTableUses.swap(SavedVTableUses);
-
-    // Restore the set of pending implicit instantiations.
-    assert(PendingInstantiations.empty() &&
-           "PendingInstantiations should be empty before it is discarded.");
-    PendingInstantiations.swap(SavedPendingInstantiations);
+    // Restore PendingInstantiations and VTableUses.
+    SavePendingInstantiationsAndVTableUses.reset();
   }
 }