Merge pull request #30645 from gottesmm/pr-61aed6aa9d21ec70e2c27e6e16e3c5edf2daed0b

[blotmapvector] Add support for try_emplace.

Author: gottesmm

include/swift/Basic/BlotMapVector.h

@@ -66,15 +66,40 @@ class BlotMapVector {
     return Vector[Pair.first->second].getValue().second;
   }
 
-  std::pair<iterator, bool> insert(const std::pair<KeyT, ValueT> &InsertPair) {
-    auto Pair = Map.insert(std::make_pair(InsertPair.first, size_t(0)));
-    if (Pair.second) {
-      size_t Num = Vector.size();
-      Pair.first->second = Num;
-      Vector.push_back(InsertPair);
-      return std::make_pair(Vector.begin() + Num, true);
+  template <typename... Ts>
+  std::pair<iterator, bool> try_emplace(KeyT &&Key, Ts &&... Args) {
+    auto Pair = Map.insert(std::make_pair(std::move(Key), size_t(0)));
+    if (!Pair.second) {
+      return std::make_pair(Vector.begin() + Pair.first->second, false);
+    }
+
+    size_t Num = Vector.size();
+    Pair.first->second = Num;
+    Vector.emplace_back(
+        std::make_pair(Pair.first->first, ValueT(std::forward<Ts>(Args)...)));
+    return std::make_pair(Vector.begin() + Num, true);
+  }
+
+  template <typename... Ts>
+  std::pair<iterator, bool> try_emplace(const KeyT &Key, Ts &&... Args) {
+    auto Pair = Map.insert(std::make_pair(std::move(Key), size_t(0)));
+    if (!Pair.second) {
+      return std::make_pair(Vector.begin() + Pair.first->second, false);
     }
-    return std::make_pair(Vector.begin() + Pair.first->second, false);
+
+    size_t Num = Vector.size();
+    Pair.first->second = Num;
+    Vector.emplace_back(
+        std::make_pair(Pair.first->first, ValueT(std::forward<Ts>(Args)...)));
+    return std::make_pair(Vector.begin() + Num, true);
+  }
+
+  std::pair<iterator, bool> insert(std::pair<KeyT, ValueT> &InsertPair) {
+    return try_emplace(InsertPair.first, InsertPair.second);
+  }
+
+  std::pair<iterator, bool> insert(const std::pair<KeyT, ValueT> &InsertPair) {
+    return try_emplace(InsertPair.first, InsertPair.second);
   }
 
   iterator find(const KeyT &Key) {

unittests/Basic/BlotMapVectorTest.cpp

@@ -464,6 +464,19 @@ TYPED_TEST(BlotMapVectorTest, InsertTest) {
   this->NumExpectedLiveTesters = 1;
 }
 
+// Test try_emplace() method
+TYPED_TEST(BlotMapVectorTest, TryEmplaceTest) {
+  this->Map.try_emplace(this->getKey(), this->getValue());
+  EXPECT_EQ(1u, this->Map.size());
+  EXPECT_EQ(this->getValue(), this->Map[this->getKey()]);
+  EXPECT_EQ(1u, this->Map.size());
+  this->Map.try_emplace(this->getKey(), this->getValue());
+  EXPECT_EQ(1u, this->Map.size());
+  EXPECT_EQ(this->getValue(), this->Map[this->getKey()]);
+  EXPECT_EQ(1u, this->Map.size());
+  this->NumExpectedLiveTesters = 1;
+}
+
 // Test copy constructor method
 TYPED_TEST(BlotMapVectorTest, CopyConstructorTest) {
   this->Map[this->getKey()] = this->getValue();