From d3ff24cbf87224b23a0c99c74ed50744711909b2 Mon Sep 17 00:00:00 2001
From: Nathan James <n.james93@hotmail.co.uk>
Date: Mon, 11 Jan 2021 20:12:53 +0000
Subject: [PATCH] [ADT] Add makeIntrusiveRefCnt helper function

Works like std::make_unique but for IntrusiveRefCntPtr objects.
See https://lists.llvm.org/pipermail/llvm-dev/2021-January/147729.html

Reviewed By: dblaikie, MaskRay

Differential Revision: https://reviews.llvm.org/D94440
---
 llvm/include/llvm/ADT/IntrusiveRefCntPtr.h    |  6 ++++++
 llvm/unittests/ADT/IntrusiveRefCntPtrTest.cpp | 16 ++++++++++++++++
 2 files changed, 22 insertions(+)

diff --git a/llvm/include/llvm/ADT/IntrusiveRefCntPtr.h b/llvm/include/llvm/ADT/IntrusiveRefCntPtr.h
index dcd35253c5f2..ca4c40db48b9 100644
--- a/llvm/include/llvm/ADT/IntrusiveRefCntPtr.h
+++ b/llvm/include/llvm/ADT/IntrusiveRefCntPtr.h
@@ -297,6 +297,12 @@ template <class T> struct simplify_type<const IntrusiveRefCntPtr<T>> {
   }
 };
 
+/// Factory function for creating intrusive ref counted pointers.
+template <typename T, typename... Args>
+IntrusiveRefCntPtr<T> makeIntrusiveRefCnt(Args &&...A) {
+  return IntrusiveRefCntPtr<T>(new T(std::forward<Args>(A)...));
+}
+
 } // end namespace llvm
 
 #endif // LLVM_ADT_INTRUSIVEREFCNTPTR_H
diff --git a/llvm/unittests/ADT/IntrusiveRefCntPtrTest.cpp b/llvm/unittests/ADT/IntrusiveRefCntPtrTest.cpp
index f69239162e3a..5dbc1b53d3fe 100644
--- a/llvm/unittests/ADT/IntrusiveRefCntPtrTest.cpp
+++ b/llvm/unittests/ADT/IntrusiveRefCntPtrTest.cpp
@@ -53,6 +53,22 @@ TYPED_TEST(IntrusiveRefCntPtrTest, InteropsWithUniquePtr) {
   EXPECT_EQ(0, NumInstances);
 }
 
+TYPED_TEST(IntrusiveRefCntPtrTest, MakeIntrusiveRefCnt) {
+  EXPECT_EQ(0, NumInstances);
+  {
+    auto S1 = makeIntrusiveRefCnt<TypeParam>();
+    auto S2 = makeIntrusiveRefCnt<const TypeParam>();
+    EXPECT_EQ(2, NumInstances);
+    static_assert(
+        std::is_same<decltype(S1), IntrusiveRefCntPtr<TypeParam>>::value,
+        "Non-const type mismatch");
+    static_assert(
+        std::is_same<decltype(S2), IntrusiveRefCntPtr<const TypeParam>>::value,
+        "Const type mismatch");
+  }
+  EXPECT_EQ(0, NumInstances);
+}
+
 struct InterceptRefCounted : public RefCountedBase<InterceptRefCounted> {
   InterceptRefCounted(bool *Released, bool *Retained)
     : Released(Released), Retained(Retained) {}