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//===-- 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"
#include "llvm/Support/Valgrind.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);
TsanHappensAfter(this);
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);
TsanHappensAfter(this);
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);
TsanHappensAfter(this);
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);
TsanHappensAfter(this);
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
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