#ifndef LLVM_SUPPORT_MANAGED_STATIC_H
#define LLVM_SUPPORT_MANAGED_STATIC_H
+#include "llvm/System/Atomic.h"
+
namespace llvm {
/// object_deleter - Helper method for ManagedStatic.
/// ManagedStaticBase - Common base class for ManagedStatic instances.
class ManagedStaticBase {
protected:
+ mutable sys::cas_flag InitFlag;
+
// This should only be used as a static variable, which guarantees that this
// will be zero initialized.
mutable void *Ptr;
// Accessors.
C &operator*() {
- if (!Ptr) LazyInit();
+ sys::cas_flag OldFlag = sys::CompareAndSwap(&InitFlag, 1, 0);
+ if (OldFlag == 0) {
+ LazyInit();
+ sys::MemoryFence();
+ InitFlag = 2;
+ } else if (OldFlag == 1)
+ while (OldFlag == 1) ;
+
return *static_cast<C*>(Ptr);
}
C *operator->() {
- if (!Ptr) LazyInit();
+ sys::cas_flag OldFlag = sys::CompareAndSwap(&InitFlag, 1, 0);
+ if (OldFlag == 0) {
+ LazyInit();
+ sys::MemoryFence();
+ InitFlag = 2;
+ } else if (OldFlag == 1)
+ while (OldFlag == 1) ;
+
return static_cast<C*>(Ptr);
}
const C &operator*() const {
- if (!Ptr) LazyInit();
+ sys::cas_flag OldFlag = sys::CompareAndSwap(&InitFlag, 1, 0);
+ if (OldFlag == 0) {
+ LazyInit();
+ sys::MemoryFence();
+ InitFlag = 2;
+ } else if (OldFlag == 1)
+ while (OldFlag == 1) ;
+
return *static_cast<C*>(Ptr);
}
const C *operator->() const {
- if (!Ptr) LazyInit();
+ sys::cas_flag OldFlag = sys::CompareAndSwap(&InitFlag, 1, 0);
+ if (OldFlag == 0) {
+ LazyInit();
+ sys::MemoryFence();
+ InitFlag = 2;
+ } else if (OldFlag == 1)
+ while (OldFlag == 1) ;
+
return static_cast<C*>(Ptr);
}