1 files changed, 120 insertions, 0 deletions
diff --git a/include/llvm/Support/ManagedStatic.h b/include/llvm/Support/ManagedStatic.h
new file mode 100644
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--- /dev/null
+++ b/include/llvm/Support/ManagedStatic.h
@@ -0,0 +1,120 @@
+//===-- llvm/Support/ManagedStatic.h - Static Global wrapper ----*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines the ManagedStatic class and the llvm_shutdown() function.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_SUPPORT_MANAGED_STATIC_H
+#define LLVM_SUPPORT_MANAGED_STATIC_H
+
+#include "llvm/System/Atomic.h"
+
+namespace llvm {
+
+/// object_creator - Helper method for ManagedStatic.
+template<class C>
+void* object_creator() {
+  return new C();
+}
+
+/// object_deleter - Helper method for ManagedStatic.
+///
+template<class C>
+void object_deleter(void *Ptr) {
+  delete (C*)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 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 != 0; }
+
+  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 ManagedStatic : public ManagedStaticBase {
+public:
+
+  // Accessors.
+  C &operator*() {
+    void* tmp = Ptr;
+    sys::MemoryFence();
+    if (!tmp) RegisterManagedStatic(object_creator<C>, object_deleter<C>);
+
+    return *static_cast<C*>(Ptr);
+  }
+  C *operator->() {
+    void* tmp = Ptr;
+    sys::MemoryFence();
+    if (!tmp) RegisterManagedStatic(object_creator<C>, object_deleter<C>);
+
+    return static_cast<C*>(Ptr);
+  }
+  const C &operator*() const {
+    void* tmp = Ptr;
+    sys::MemoryFence();
+    if (!tmp) RegisterManagedStatic(object_creator<C>, object_deleter<C>);
+
+    return *static_cast<C*>(Ptr);
+  }
+  const C *operator->() const {
+    void* tmp = Ptr;
+    sys::MemoryFence();
+    if (!tmp) RegisterManagedStatic(object_creator<C>, object_deleter<C>);
+
+    return static_cast<C*>(Ptr);
+  }
+};
+
+template<void (*CleanupFn)(void*)>
+class ManagedCleanup : public ManagedStaticBase {
+public:
+  void Register() { RegisterManagedStatic(0, CleanupFn); }
+};
+
+
+/// llvm_start_multithreaded - Allocate and initialize structures needed to
+/// make LLVM safe for multithreading.  The return value indicates whether
+/// multithreaded initialization succeeded.  LLVM will still be operational
+/// on "failed" return, but will not be safe to run multithreaded.
+bool llvm_start_multithreaded();
+
+/// 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() { }
+  explicit llvm_shutdown_obj(bool multithreaded) {
+    if (multithreaded) llvm_start_multithreaded();
+  }
+  ~llvm_shutdown_obj() { llvm_shutdown(); }
+};
+
+}
+
+#endif