1 files changed, 83 insertions, 0 deletions
diff --git a/llvm/lib/Support/ManagedStatic.cpp b/llvm/lib/Support/ManagedStatic.cpp
new file mode 100644
index 000000000000..053493f72fb5
--- /dev/null
+++ b/llvm/lib/Support/ManagedStatic.cpp
@@ -0,0 +1,83 @@
+//===-- ManagedStatic.cpp - Static Global wrapper -------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the ManagedStatic class and llvm_shutdown().
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Support/ManagedStatic.h"
+#include "llvm/Config/config.h"
+#include "llvm/Support/Threading.h"
+#include <cassert>
+#include <mutex>
+using namespace llvm;
+
+static const ManagedStaticBase *StaticList = nullptr;
+static std::recursive_mutex *ManagedStaticMutex = nullptr;
+static llvm::once_flag mutex_init_flag;
+
+static void initializeMutex() {
+  ManagedStaticMutex = new std::recursive_mutex();
+}
+
+static std::recursive_mutex *getManagedStaticMutex() {
+  llvm::call_once(mutex_init_flag, initializeMutex);
+  return ManagedStaticMutex;
+}
+
+void ManagedStaticBase::RegisterManagedStatic(void *(*Creator)(),
+                                              void (*Deleter)(void*)) const {
+  assert(Creator);
+  if (llvm_is_multithreaded()) {
+    std::lock_guard<std::recursive_mutex> Lock(*getManagedStaticMutex());
+
+    if (!Ptr.load(std::memory_order_relaxed)) {
+      void *Tmp = Creator();
+
+      Ptr.store(Tmp, std::memory_order_release);
+      DeleterFn = Deleter;
+
+      // Add to list of managed statics.
+      Next = StaticList;
+      StaticList = this;
+    }
+  } else {
+    assert(!Ptr && !DeleterFn && !Next &&
+           "Partially initialized ManagedStatic!?");
+    Ptr = Creator();
+    DeleterFn = Deleter;
+
+    // Add to list of managed statics.
+    Next = StaticList;
+    StaticList = this;
+  }
+}
+
+void ManagedStaticBase::destroy() const {
+  assert(DeleterFn && "ManagedStatic not initialized correctly!");
+  assert(StaticList == this &&
+         "Not destroyed in reverse order of construction?");
+  // Unlink from list.
+  StaticList = Next;
+  Next = nullptr;
+
+  // Destroy memory.
+  DeleterFn(Ptr);
+
+  // Cleanup.
+  Ptr = nullptr;
+  DeleterFn = nullptr;
+}
+
+/// llvm_shutdown - Deallocate and destroy all ManagedStatic variables.
+void llvm::llvm_shutdown() {
+  std::lock_guard<std::recursive_mutex> Lock(*getManagedStaticMutex());
+
+  while (StaticList)
+    StaticList->destroy();
+}