[ADT] Group public functions in DenseMap.h (NFC) (#168239)

This patch groups public functions, including the constructors, the
destructor, and the copy/move assignment operators.

Author: kazutakahirata

llvm/include/llvm/ADT/DenseMap.h

@@ -772,15 +772,6 @@ class DenseMap : public DenseMapBase<DenseMap<KeyT, ValueT, KeyInfoT, BucketT>,
     deallocateBuckets();
   }
 
-private:
-  void swapImpl(DenseMap &RHS) {
-    std::swap(Buckets, RHS.Buckets);
-    std::swap(NumEntries, RHS.NumEntries);
-    std::swap(NumTombstones, RHS.NumTombstones);
-    std::swap(NumBuckets, RHS.NumBuckets);
-  }
-
-public:
   DenseMap &operator=(const DenseMap &other) {
     if (&other != this)
       this->copyFrom(other);
@@ -796,6 +787,13 @@ class DenseMap : public DenseMapBase<DenseMap<KeyT, ValueT, KeyInfoT, BucketT>,
   }
 
 private:
+  void swapImpl(DenseMap &RHS) {
+    std::swap(Buckets, RHS.Buckets);
+    std::swap(NumEntries, RHS.NumEntries);
+    std::swap(NumTombstones, RHS.NumTombstones);
+    std::swap(NumBuckets, RHS.NumBuckets);
+  }
+
   unsigned getNumEntries() const { return NumEntries; }
 
   void setNumEntries(unsigned Num) { NumEntries = Num; }
@@ -945,6 +943,20 @@ class SmallDenseMap
     deallocateBuckets();
   }
 
+  SmallDenseMap &operator=(const SmallDenseMap &other) {
+    if (&other != this)
+      this->copyFrom(other);
+    return *this;
+  }
+
+  SmallDenseMap &operator=(SmallDenseMap &&other) {
+    this->destroyAll();
+    deallocateBuckets();
+    init(0);
+    this->swap(other);
+    return *this;
+  }
+
 private:
   void swapImpl(SmallDenseMap &RHS) {
     unsigned TmpNumEntries = RHS.NumEntries;
@@ -1017,22 +1029,6 @@ class SmallDenseMap
     new (SmallSide.getLargeRep()) LargeRep(std::move(TmpRep));
   }
 
-public:
-  SmallDenseMap &operator=(const SmallDenseMap &other) {
-    if (&other != this)
-      this->copyFrom(other);
-    return *this;
-  }
-
-  SmallDenseMap &operator=(SmallDenseMap &&other) {
-    this->destroyAll();
-    deallocateBuckets();
-    init(0);
-    this->swap(other);
-    return *this;
-  }
-
-private:
   unsigned getNumEntries() const { return NumEntries; }
 
   void setNumEntries(unsigned Num) {