1 files changed, 24 insertions, 19 deletions

diff --git a/include/llvm/ADT/StringMap.h b/include/llvm/ADT/StringMap.h
index 5b18681879..c40e5e2b3d 100644
--- a/include/llvm/ADT/StringMap.h
+++ b/include/llvm/ADT/StringMap.h
@@ -64,7 +64,7 @@ protected:
   }
 
   StringMapImpl(unsigned InitSize, unsigned ItemSize);
-  void RehashTable();
+  unsigned RehashTable(unsigned BucketNo = 0);
 
   /// LookupBucketFor - Look up the bucket that the specified string should end
   /// up in.  If it already exists as a key in the map, the Item pointer for the
@@ -323,6 +323,28 @@ public:
     return true;
   }
 
+  /// insert - Inserts the specified key/value pair into the map if the key
+  /// isn't already in the map. The bool component of the returned pair is true
+  /// if and only if the insertion takes place, and the iterator component of
+  /// the pair points to the element with key equivalent to the key of the pair.
+  std::pair<iterator, bool> insert(std::pair<StringRef, ValueTy> KV) {
+    unsigned BucketNo = LookupBucketFor(KV.first);
+    StringMapEntryBase *&Bucket = TheTable[BucketNo];
+    if (Bucket && Bucket != getTombstoneVal())
+      return std::make_pair(iterator(TheTable + BucketNo, false),
+                            false); // Already exists in map.
+
+    if (Bucket == getTombstoneVal())
+      --NumTombstones;
+    Bucket =
+        MapEntryTy::Create(KV.first, Allocator, std::move(KV.second));
+    ++NumItems;
+    assert(NumItems + NumTombstones <= NumBuckets);
+
+    BucketNo = RehashTable(BucketNo);
+    return std::make_pair(iterator(TheTable + BucketNo, false), true);
+  }
+
   // clear - Empties out the StringMap
   void clear() {
     if (empty()) return;
@@ -346,24 +368,7 @@ public:
   /// return.
   template <typename InitTy>
   MapEntryTy &GetOrCreateValue(StringRef Key, InitTy Val) {
-    unsigned BucketNo = LookupBucketFor(Key);
-    StringMapEntryBase *&Bucket = TheTable[BucketNo];
-    if (Bucket && Bucket != getTombstoneVal())
-      return *static_cast<MapEntryTy*>(Bucket);
-
-    MapEntryTy *NewItem = MapEntryTy::Create(Key, Allocator, std::move(Val));
-
-    if (Bucket == getTombstoneVal())
-      --NumTombstones;
-    ++NumItems;
-    assert(NumItems + NumTombstones <= NumBuckets);
-
-    // Fill in the bucket for the hash table.  The FullHashValue was already
-    // filled in by LookupBucketFor.
-    Bucket = NewItem;
-
-    RehashTable();
-    return *NewItem;
+    return *insert(std::make_pair(Key, std::move(Val))).first;
   }
 
   MapEntryTy &GetOrCreateValue(StringRef Key) {