Merge "Update prebuilt Clang to r353983." into p9.0HEADp9.0-backupp9.0

1 files changed, 96 insertions, 0 deletions

diff --git a/clang-r353983/include/llvm/Support/ManagedStatic.h b/clang-r353983/include/llvm/Support/ManagedStatic.h
new file mode 100644
index 00000000..441f24e0
--- /dev/null
+++ b/clang-r353983/include/llvm/Support/ManagedStatic.h
@@ -0,0 +1,96 @@
+//===-- llvm/Support/ManagedStatic.h - Static Global wrapper ----*- C++ -*-===//
+//
+// 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 defines the ManagedStatic class and the llvm_shutdown() function.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_SUPPORT_MANAGEDSTATIC_H
+#define LLVM_SUPPORT_MANAGEDSTATIC_H
+
+#include <atomic>
+#include <cstddef>
+
+namespace llvm {
+
+/// object_creator - Helper method for ManagedStatic.
+template <class C> struct object_creator {
+  static void *call() { return new C(); }
+};
+
+/// object_deleter - Helper method for ManagedStatic.
+///
+template <typename T> struct object_deleter {
+  static void call(void *Ptr) { delete (T *)Ptr; }
+};
+template <typename T, size_t N> struct object_deleter<T[N]> {
+  static void call(void *Ptr) { delete[](T *)Ptr; }
+};
+
+/// ManagedStaticBase - Common base class for ManagedStatic instances.
+class ManagedStaticBase {
+protected:
+  // This should only be used as a static variable, which guarantees that this
+  // will be zero initialized.
+  mutable std::atomic<void *> Ptr;
+  mutable void (*DeleterFn)(void*);
+  mutable const ManagedStaticBase *Next;
+
+  void RegisterManagedStatic(void *(*creator)(), void (*deleter)(void*)) const;
+
+public:
+  /// isConstructed - Return true if this object has not been created yet.
+  bool isConstructed() const { return Ptr != nullptr; }
+
+  void destroy() const;
+};
+
+/// ManagedStatic - This transparently changes the behavior of global statics to
+/// be lazily constructed on demand (good for reducing startup times of dynamic
+/// libraries that link in LLVM components) and for making destruction be
+/// explicit through the llvm_shutdown() function call.
+///
+template <class C, class Creator = object_creator<C>,
+          class Deleter = object_deleter<C>>
+class ManagedStatic : public ManagedStaticBase {
+public:
+  // Accessors.
+  C &operator*() {
+    void *Tmp = Ptr.load(std::memory_order_acquire);
+    if (!Tmp)
+      RegisterManagedStatic(Creator::call, Deleter::call);
+
+    return *static_cast<C *>(Ptr.load(std::memory_order_relaxed));
+  }
+
+  C *operator->() { return &**this; }
+
+  const C &operator*() const {
+    void *Tmp = Ptr.load(std::memory_order_acquire);
+    if (!Tmp)
+      RegisterManagedStatic(Creator::call, Deleter::call);
+
+    return *static_cast<C *>(Ptr.load(std::memory_order_relaxed));
+  }
+
+  const C *operator->() const { return &**this; }
+};
+
+/// llvm_shutdown - Deallocate and destroy all ManagedStatic variables.
+void llvm_shutdown();
+
+/// llvm_shutdown_obj - This is a simple helper class that calls
+/// llvm_shutdown() when it is destroyed.
+struct llvm_shutdown_obj {
+  llvm_shutdown_obj() = default;
+  ~llvm_shutdown_obj() { llvm_shutdown(); }
+};
+
+} // end namespace llvm
+
+#endif // LLVM_SUPPORT_MANAGEDSTATIC_H