29  * guard.cc: Functions for thread-safe static initialisation.
66  * The Itanium C++ ABI defines guard words that are 64-bit (32-bit on AArch32)
73  * an ordering on them such that the guard word is never modified unless the
75  * locking by loading the guard word and, if it is not initialised, trying to
77  * manipulate the guard word.
82 	 * The state of the guard variable when an attempt is made to lock it.
105 	 * guard.  The word size is defined by the type of `GuardWord`.  The bit
126 		 * The guard variable.
172 		 * Check whether the guard indicates that the variable is initialised.
183 	 * guard variable.
268 	              "Single-word 32-bit guard must be 32 bits");
270 	              "Single-word 64-bit guard must be 64 bits");
272 	              "Double-word guard must be 64 bits");
278 	using Guard = SingleWordGuard<uint32_t, 31, 0>;  typedef
282 	 * On little-endian 64-bit platforms the guard word is a single 64-bit
286 	using Guard = SingleWordGuard<uint64_t, 63, 0>;  typedef
289 	 * On bit-endian 64-bit platforms, the guard word is a single 64-bit atomic
293 	using Guard = SingleWordGuard<uint64_t, 0, 56>;  typedef
300 	using Guard = DoubleWordGuard<31, 0>;  typedef
305 	using Guard = DoubleWordGuard<0, 24>;  typedef
312  * Acquires a lock on a guard, returning 0 if the object has already been
316 extern "C" int __cxa_guard_acquire(Guard *guard_object)  in __cxa_guard_acquire()
354 extern "C" void __cxa_guard_abort(Guard *guard_object)  in __cxa_guard_abort()
360  * Releases the guard and marks the object as initialised.  This function is
363 extern "C" void __cxa_guard_release(Guard *guard_object)  in __cxa_guard_release()