//===-- 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/Support/Atomic.h" #include "llvm/Support/Threading.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<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 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; if (llvm_is_multithreaded()) sys::MemoryFence(); if (!tmp) RegisterManagedStatic(object_creator<C>, object_deleter<C>::call); return *static_cast<C*>(Ptr); } C *operator->() { void* tmp = Ptr; if (llvm_is_multithreaded()) sys::MemoryFence(); if (!tmp) RegisterManagedStatic(object_creator<C>, object_deleter<C>::call); return static_cast<C*>(Ptr); } const C &operator*() const { void* tmp = Ptr; if (llvm_is_multithreaded()) sys::MemoryFence(); if (!tmp) RegisterManagedStatic(object_creator<C>, object_deleter<C>::call); return *static_cast<C*>(Ptr); } const C *operator->() const { void* tmp = Ptr; if (llvm_is_multithreaded()) sys::MemoryFence(); if (!tmp) RegisterManagedStatic(object_creator<C>, object_deleter<C>::call); return static_cast<C*>(Ptr); } }; /// 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