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, 15 insertions, 1 deletions

diff --git a/gold/target-select.cc b/gold/target-select.cc
index b81f5a2..55d63b2 100644
--- a/gold/target-select.cc
+++ b/gold/target-select.cc
@@ -46,13 +46,27 @@ namespace gold
 Target_selector::Target_selector(int machine, int size, bool is_big_endian,
 				 const char* bfd_name)
   : machine_(machine), size_(size), is_big_endian_(is_big_endian),
-    bfd_name_(bfd_name), instantiated_target_(NULL)
+    bfd_name_(bfd_name), instantiated_target_(NULL), lock_(NULL),
+    initialize_lock_(&this->lock_)
     
 {
   this->next_ = target_selectors;
   target_selectors = this;
 }
 
+// Instantiate the target and return it.  Use a lock to avoid
+// instantiating two instances of the same target.
+
+Target*
+Target_selector::instantiate_target()
+{
+  this->initialize_lock_.initialize();
+  Hold_optional_lock hl(this->lock_);
+  if (this->instantiated_target_ == NULL)
+    this->instantiated_target_ = this->do_instantiate_target();
+  return this->instantiated_target_;
+}
+
 // Find the target for an ELF file.
 
 Target*