X-Git-Url: http://git.efficios.com/?a=blobdiff_plain;f=gold%2Fgold-threads.cc;h=f972a8c97d35a2cb17001658e87eb5ca74ef5407;hb=85e290dc1252d77e726c0892b197be449b34bd16;hp=e54d96c6ec7b2c7d507c647450e271cd8c4a566d;hpb=8851eccaec28f25f56fab5ba5d8ae44f71729975;p=deliverable%2Fbinutils-gdb.git

diff --git a/gold/gold-threads.cc b/gold/gold-threads.cc
index e54d96c6ec..f972a8c97d 100644
--- a/gold/gold-threads.cc
+++ b/gold/gold-threads.cc
@@ -1,6 +1,6 @@
 // gold-threads.cc -- thread support for gold
 
-// Copyright 2006, 2007 Free Software Foundation, Inc.
+// Copyright (C) 2006-2020 Free Software Foundation, Inc.
 // Written by Ian Lance Taylor <iant@google.com>.
 
 // This file is part of gold.
@@ -100,14 +100,14 @@ Lock_impl_threads::Lock_impl_threads()
   pthread_mutexattr_t attr;
   int err = pthread_mutexattr_init(&attr);
   if (err != 0)
-    gold_fatal(_("pthead_mutextattr_init failed: %s"), strerror(err));
-#ifdef PTHREAD_MUTEXT_ADAPTIVE_NP
-  err = pthread_mutextattr_settype(&attr, PTHREAD_MUTEX_ADAPTIVE_NP);
+    gold_fatal(_("pthead_mutexattr_init failed: %s"), strerror(err));
+#ifdef PTHREAD_MUTEX_ADAPTIVE_NP
+  err = pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_ADAPTIVE_NP);
   if (err != 0)
-    gold_fatal(_("pthread_mutextattr_settype failed: %s"), strerror(err));
+    gold_fatal(_("pthread_mutexattr_settype failed: %s"), strerror(err));
 #endif
 
-  err = pthread_mutex_init (&this->mutex_, &attr);
+  err = pthread_mutex_init(&this->mutex_, &attr);
   if (err != 0)
     gold_fatal(_("pthread_mutex_init failed: %s"), strerror(err));
 
@@ -276,4 +276,175 @@ Condvar::~Condvar()
   delete this->condvar_;
 }
 
+#ifdef ENABLE_THREADS
+
+// Class Once_initialize.  This exists to hold a pthread_once_t
+// structure for Once.
+
+class Once_initialize
+{
+ public:
+  Once_initialize()
+    : once_(PTHREAD_ONCE_INIT)
+  { }
+
+  // Return a pointer to the pthread_once_t variable.
+  pthread_once_t*
+  once_control()
+  { return &this->once_; }
+
+ private:
+  pthread_once_t once_;
+};
+
+#endif // defined(ENABLE_THREADS)
+
+#ifdef ENABLE_THREADS
+
+// A single lock which controls access to once_pointer.  This is used
+// because we can't pass parameters to functions passed to
+// pthread_once.
+
+static pthread_mutex_t once_pointer_control = PTHREAD_MUTEX_INITIALIZER;
+
+// A pointer to Once structure we want to run.  Access to this is
+// controlled by once_pointer_control.
+
+static Once* once_pointer;
+
+// The argument to pass to the Once structure.  Access to this is
+// controlled by once_pointer_control.
+
+static void* once_arg;
+
+// A routine passed to pthread_once which runs the Once pointer.
+
+extern "C"
+{
+
+static void
+c_run_once(void)
+{
+  once_pointer->internal_run(once_arg);
+}
+
+}
+
+#endif // defined(ENABLE_THREADS)
+
+// Class Once.
+
+Once::Once()
+  : was_run_(false)
+#if defined(ENABLE_THREADS) && defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4)
+    , was_run_lock_(0)
+#endif
+{
+#ifndef ENABLE_THREADS
+  this->once_ = NULL;
+#else
+  this->once_ = new Once_initialize();
+#endif
+}
+
+// Run the function once.
+
+void
+Once::run_once(void* arg)
+{
+#ifndef ENABLE_THREADS
+
+  // If there is no threads support, we don't need to use pthread_once.
+  if (!this->was_run_)
+    this->internal_run(arg);
+
+#else // defined(ENABLE_THREADS)
+
+  if (parameters->options_valid() && !parameters->options().threads())
+    {
+      // If we are not using threads, we don't need to lock.
+      if (!this->was_run_)
+	this->internal_run(arg);
+      return;
+    }
+
+  // If we have the sync builtins, use them to skip the lock if the
+  // value has already been initialized.
+#ifdef __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4
+  while (true)
+    {
+      if (__sync_bool_compare_and_swap(&this->was_run_lock_, 0, 1))
+	break;
+    }
+  bool was_run = this->was_run_;
+  while (true)
+    {
+      if (__sync_bool_compare_and_swap(&this->was_run_lock_, 1, 0))
+	break;
+    }
+  if (was_run)
+    return;
+#endif
+
+  // Since we can't pass parameters to routines called by
+  // pthread_once, we use a static variable: once_pointer.  This in
+  // turns means that we need to use a mutex to control access to
+  // once_pointer.
+
+  int err = pthread_mutex_lock(&once_pointer_control);
+  if (err != 0)
+    gold_fatal(_("pthread_mutex_lock failed: %s"), strerror(err));
+
+  once_pointer = this;
+  once_arg = arg;
+
+  err = pthread_once(this->once_->once_control(), c_run_once);
+  if (err != 0)
+    gold_fatal(_("pthread_once failed: %s"), strerror(err));
+
+  once_pointer = NULL;
+  once_arg = NULL;
+
+  err = pthread_mutex_unlock(&once_pointer_control);
+  if (err != 0)
+    gold_fatal(_("pthread_mutex_unlock failed: %s"), strerror(err));
+
+#endif // defined(ENABLE_THREADS)
+}
+
+// Actually run the function in the child class.  This function will
+// be run only once.
+
+void
+Once::internal_run(void* arg)
+{
+  this->do_run_once(arg);
+  this->was_run_ = true;
+}
+
+// Class Initialize_lock.
+
+// Initialize the lock.
+
+bool
+Initialize_lock::initialize()
+{
+  // We can't initialize the lock until we have read the options.
+  if (!parameters->options_valid())
+    return false;
+  else
+    {
+      this->run_once(NULL);
+      return true;
+    }
+}
+
+// Initialize the lock exactly once.
+
+void
+Initialize_lock::do_run_once(void*)
+{
+  *this->pplock_ = new Lock();
+}
+
 } // End namespace gold.