2009-03-23 Ian Lance Taylor <iant@google.com>

	* gold-threads.h (class Initialize_lock): Define.
	* gold-threads.cc (class Initialize_lock_once): Define.
	(initialize_lock_control): New static variable.
	(initialize_lock_pointer): New static variable.
	(initialize_lock_once): New static function.
	(Initialize_lock::Initialize_lock): Define.
	(Initialize_lock::initialize): Define.
	* target-select.h: Include "gold-threads.h".
	(class Target_selector): Add lock_ and initialize_lock_ fields.
	Don't define instantiate_target, just declare it.
	* target-select.cc (Target_selector::Target_selector): Initialize
	new fields.
	(Target_selector::instantiate_target): Define.
	* descriptors.h: Include "gold-threads.h".
	(class Descriptors): Add initialize_lock_ field.
	* descriptors.cc (Descriptors::Descriptors): Initialize new
	field.
	(Descriptors::open): Use initialize_lock_ field
	* errors.h (class Errors): Add initialize_lock_ field.
	* errors.cc (Errors::Errors): Initialize new field.
	(Errors::initialize_lock): Use initialize_lock_ field.
	* powerpc.cc (class Target_selector_powerpc): Remove
	instantiated_target_ field.  In do_recognize call
	instantiate_target rather than do_instantiate_target.  In
	do_instantiate_target just allocate a new target.
	* sparc.cc (class Target_selector_sparc): Likewise.

1 files changed, 28 insertions, 0 deletions

diff --git a/gold/gold-threads.h b/gold/gold-threads.h
index c901e42e50e..9c49b57d071 100644
--- a/gold/gold-threads.h
+++ b/gold/gold-threads.h
@@ -35,6 +35,7 @@ namespace gold
 {
 
 class Condvar;
+class Initialize_lock_once;
 
 // The interface for the implementation of a Lock.
 
@@ -190,6 +191,33 @@ class Condvar
   Condvar_impl* condvar_;
 };
 
+// A class used to initialize a lock exactly once, after the options
+// have been read.  This is needed because the implementation of locks
+// depends on whether we've seen the --threads option.  Before the
+// options have been read, we know we are single-threaded, so we can
+// get by without using a lock.  This class should be an instance
+// variable of the class which has a lock which needs to be
+// initialized.
+
+class Initialize_lock
+{
+ public:
+  // The class which uses this will have a pointer to a lock.  This
+  // must be constructed with a pointer to that pointer.
+  Initialize_lock(Lock** pplock);
+
+  // Initialize the lock.  Return true if the lock is now initialized,
+  // false if it is not (because the options have not yet been read).
+  bool
+  initialize();
+
+ private:
+  // A pointer to the lock pointer which must be initialized.
+  Lock** const pplock_;
+  // If needed, a pointer to a pthread_once_t structure.
+  Initialize_lock_once* once_;
+};
+
 } // End namespace gold.
 
 #endif // !defined(GOLD_THREADS_H)