[Support] Recycler: Implement move constructor (#120555)

Discovered missing while running RAGreedy through the NPM which relies on moving analyses to the cache.

Author: optimisan

llvm/include/llvm/Support/Recycler.h

@@ -60,6 +60,10 @@ class Recycler {
  // clear() before deleting the Recycler.
  assert(!FreeList && "Non-empty recycler deleted!");
  }
+ Recycler(const Recycler &) = delete;
+ Recycler(Recycler &&Other)
+ : FreeList(std::exchange(Other.FreeList, nullptr)) {}
+ Recycler() = default;
 
  /// clear - Release all the tracked allocations to the allocator. The
  /// recycler must be free of any tracked allocations before being

llvm/unittests/Support/CMakeLists.txt

@@ -69,6 +69,7 @@ add_llvm_unittest(SupportTests
  PerThreadBumpPtrAllocatorTest.cpp
  ProcessTest.cpp
  ProgramTest.cpp
+ RecyclerTest.cpp
  RegexTest.cpp
  ReverseIterationTest.cpp
  ReplaceFileTest.cpp

llvm/unittests/Support/RecyclerTest.cpp

@@ -0,0 +1,47 @@
+//===--- unittest/Support/RecyclerTest.cpp --------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Support/Recycler.h"
+#include "llvm/Support/AllocatorBase.h"
+#include "gtest/gtest.h"
+
+using namespace llvm;
+
+namespace {
+
+struct Object8 {
+ char Data[8];
+};
+
+class DecoratedMallocAllocator : public MallocAllocator {
+public:
+ int DeallocCount = 0;
+
+ template <typename T> void Deallocate(T *Ptr) {
+ DeallocCount++;
+ MallocAllocator::Deallocate(Ptr);
+ }
+};
+
+TEST(RecyclerTest, MoveConstructor) {
+ DecoratedMallocAllocator Allocator;
+ Recycler<Object8> R;
+ Object8 *A1 = R.Allocate(Allocator);
+ Object8 *A2 = R.Allocate(Allocator);
+ R.Deallocate(Allocator, A1);
+ R.Deallocate(Allocator, A2);
+ Recycler<Object8> R2(std::move(R));
+ Object8 *A3 = R2.Allocate(Allocator);
+ R2.Deallocate(Allocator, A3);
+ R.clear(Allocator); // Should not deallocate anything as it was moved from.
+ EXPECT_EQ(Allocator.DeallocCount, 0);
+ R2.clear(Allocator);
+ EXPECT_EQ(Allocator.DeallocCount, 2);
+}
+
+} // end anonymous namespace