Use annotate_object_leaked() in LeakySingleton

Summary:
Use `folly::annotate_object_leaked()` in `folly::LeakySingleton`
instead of its own custom suppression. Additionally, this removes
the overhead of the `std::list<>` in opt-mode, but this is minor.

Reviewed By: yfeldblum

Differential Revision: D15755787

fbshipit-source-id: 053b8789c58941176977e6adbc4863d33d6ebed9

folly/Singleton.h

@@ -130,6 +130,7 @@
 #include <folly/experimental/ReadMostlySharedPtr.h>
 #include <folly/hash/Hash.h>
 #include <folly/lang/Exception.h>
+#include <folly/memory/SanitizeLeak.h>
 #include <folly/synchronization/Baton.h>
 #include <folly/synchronization/RWSpinLock.h>
 
@@ -717,8 +718,7 @@ class LeakySingleton {
 
     auto& entry = entryInstance();
     if (entry.ptr) {
-      // Make sure existing pointer doesn't get reported as a leak by LSAN.
-      entry.leakedPtrs.push_back(std::exchange(entry.ptr, nullptr));
+      annotate_object_leaked(std::exchange(entry.ptr, nullptr));
     }
     entry.createFunc = createFunc;
     entry.state = State::Dead;
@@ -737,7 +737,6 @@ class LeakySingleton {
     CreateFunc createFunc;
     std::mutex mutex;
     detail::TypeDescriptor type_{typeid(T), typeid(Tag)};
-    std::list<T*> leakedPtrs;
   };
 
   static Entry& entryInstance() {

folly/test/SingletonTest.cpp

@@ -783,3 +783,14 @@ TEST(Singleton, DoubleMakeMockAfterTryGet) {
   EXPECT_EQ(1, counts.ctor);
   EXPECT_EQ(1, counts.dtor);
 }
+
+TEST(Singleton, LeakySingletonLSAN) {
+  struct PrivateTag {};
+  static folly::LeakySingleton<int, PrivateTag> gPtr;
+  auto* ptr0 = &gPtr.get();
+  EXPECT_EQ(*ptr0, 0);
+  gPtr.make_mock([] { return new int(1); });
+  auto* ptr1 = &gPtr.get();
+  EXPECT_NE(ptr0, ptr1);
+  EXPECT_EQ(*ptr1, 1);
+}