Ensure that getCoreAllocator() is shared across DSOs

Summary: The allocator instances may not be shared across DSOs that are loaded with `RTLD_LOCAL`.

Reviewed By: yfeldblum

Differential Revision: D29955690

fbshipit-source-id: 914196a072a1bb0709d772ba0cddc6319acde862

folly/concurrency/CacheLocality.h

@@ -32,6 +32,7 @@
 #include <folly/Likely.h>
 #include <folly/Memory.h>
 #include <folly/Portability.h>
+#include <folly/detail/StaticSingletonManager.h>
 #include <folly/lang/Align.h>
 #include <folly/lang/Exception.h>
 
@@ -474,9 +475,9 @@ class CoreRawAllocator {
     }
   };
 
-  Allocator* get(size_t stripe) {
+  Allocator& get(size_t stripe) {
     assert(stripe < Stripes);
-    return &allocators_[stripe];
+    return allocators_[stripe];
   }
 
  private:
@@ -484,14 +485,11 @@ class CoreRawAllocator {
 };
 
 template <typename T, size_t Stripes>
-FOLLY_EXPORT
-    CxxAllocatorAdaptor<T, typename CoreRawAllocator<Stripes>::Allocator>
-    getCoreAllocator(size_t stripe) {
-  // We cannot make sure that the allocator will be destroyed after
-  // all the objects allocated with it, so we leak it.
-  static Indestructible<CoreRawAllocator<Stripes>> allocator;
-  return CxxAllocatorAdaptor<T, typename CoreRawAllocator<Stripes>::Allocator>(
-      *allocator->get(stripe));
+CxxAllocatorAdaptor<T, typename CoreRawAllocator<Stripes>::Allocator>
+getCoreAllocator(size_t stripe) {
+  using RawAllocator = CoreRawAllocator<Stripes>;
+  return CxxAllocatorAdaptor<T, typename RawAllocator::Allocator>(
+      detail::createGlobal<RawAllocator, void>().get(stripe));
 }
 
 } // namespace folly

folly/concurrency/test/CacheLocalityTest.cpp

@@ -1144,28 +1144,28 @@ TEST(AccessSpreader, Wrapping) {
 
 TEST(CoreRawAllocator, Basic) {
   CoreRawAllocator<32> alloc;
-  auto a = alloc.get(0);
-  auto res = a->allocate(8);
+  auto& a = alloc.get(0);
+  auto res = a.allocate(8);
   memset(res, 0, 8);
-  a->deallocate(res);
-  res = a->allocate(8);
+  a.deallocate(res);
+  res = a.allocate(8);
   EXPECT_TRUE((intptr_t)res % 8 == 0); // check alignment
   memset(res, 0, 8);
-  a->deallocate(res);
-  res = a->allocate(12);
+  a.deallocate(res);
+  res = a.allocate(12);
   EXPECT_TRUE((intptr_t)res % 16 == 0); // check alignment
   memset(res, 0, 12);
-  a->deallocate(res);
-  res = a->allocate(257);
+  a.deallocate(res);
+  res = a.allocate(257);
   memset(res, 0, 257);
-  a->deallocate(res);
+  a.deallocate(res);
 
   std::vector<void*> mems;
   for (int i = 0; i < 10000; i++) {
-    mems.push_back(a->allocate(1));
+    mems.push_back(a.allocate(1));
   }
   for (auto& mem : mems) {
-    a->deallocate(mem);
+    a.deallocate(mem);
   }
   mems.clear();
 }