Export of internal Abseil changes

--
b8e6b64b604449bb51ed0ba8e9439097f3aa8773 by Abseil Team <absl-team@google.com>:

fix typo 'implentation' -> 'implementation'

PiperOrigin-RevId: 311623471

--
2b9262a311f3329c8006835a79498edd90568acd by Matt Kulukundis <kfm@google.com>:

Internal cleanup

PiperOrigin-RevId: 311549039

--
7507ed3c28113e28f993aa634bd44a9a0d4c4a2c by Derek Mauro <dmauro@google.com>:

Delete LinkerInitialized

Now that all SpinLocks have the same scheduling mode for
their entire lives, the scheduling mode does not need to
be re-tested in the loop in LockSlow.

PiperOrigin-RevId: 311521474

--
abf5fae67e21b38cda4083aaafd7012e2c6fbb7d by Andy Getzendanner <durandal@google.com>:

Fix public target name of the random library

Import of https://github.com/abseil/abseil-cpp/pull/684

PiperOrigin-RevId: 311429555
GitOrigin-RevId: b8e6b64b604449bb51ed0ba8e9439097f3aa8773
Change-Id: Ic48f671846bda059cc46f4a0b967cc3b1a733ba0

1 files changed, 8 insertions, 29 deletions

diff --git a/absl/base/internal/spinlock.cc b/absl/base/internal/spinlock.cc
index 7cac72f9..a7d44f3e 100644
--- a/absl/base/internal/spinlock.cc
+++ b/absl/base/internal/spinlock.cc
@@ -79,29 +79,6 @@ SpinLock::SpinLock(base_internal::SchedulingMode mode)
   ABSL_TSAN_MUTEX_CREATE(this, __tsan_mutex_not_static);
 }
 
-SpinLock::SpinLock(base_internal::LinkerInitialized,
-                   base_internal::SchedulingMode mode) {
-  ABSL_TSAN_MUTEX_CREATE(this, 0);
-  if (IsCooperative(mode)) {
-    InitLinkerInitializedAndCooperative();
-  }
-  // Otherwise, lockword_ is already initialized.
-}
-
-// Static (linker initialized) spinlocks always start life as functional
-// non-cooperative locks.  When their static constructor does run, it will call
-// this initializer to augment the lockword with the cooperative bit.  By
-// actually taking the lock when we do this we avoid the need for an atomic
-// operation in the regular unlock path.
-//
-// SlowLock() must be careful to re-test for this bit so that any outstanding
-// waiters may be upgraded to cooperative status.
-void SpinLock::InitLinkerInitializedAndCooperative() {
-  Lock();
-  lockword_.fetch_or(kSpinLockCooperative, std::memory_order_relaxed);
-  Unlock();
-}
-
 // Monitor the lock to see if its value changes within some time period
 // (adaptive_spin_count loop iterations). The last value read from the lock
 // is returned from the method.
@@ -128,6 +105,14 @@ void SpinLock::SlowLock() {
   if ((lock_value & kSpinLockHeld) == 0) {
     return;
   }
+
+  base_internal::SchedulingMode scheduling_mode;
+  if ((lock_value & kSpinLockCooperative) != 0) {
+    scheduling_mode = base_internal::SCHEDULE_COOPERATIVE_AND_KERNEL;
+  } else {
+    scheduling_mode = base_internal::SCHEDULE_KERNEL_ONLY;
+  }
+
   // The lock was not obtained initially, so this thread needs to wait for
   // it.  Record the current timestamp in the local variable wait_start_time
   // so the total wait time can be stored in the lockword once this thread
@@ -158,12 +143,6 @@ void SpinLock::SlowLock() {
       }
     }
 
-    base_internal::SchedulingMode scheduling_mode;
-    if ((lock_value & kSpinLockCooperative) != 0) {
-      scheduling_mode = base_internal::SCHEDULE_COOPERATIVE_AND_KERNEL;
-    } else {
-      scheduling_mode = base_internal::SCHEDULE_KERNEL_ONLY;
-    }
     // SpinLockDelay() calls into fiber scheduler, we need to see
     // synchronization there to avoid false positives.
     ABSL_TSAN_MUTEX_PRE_DIVERT(this, 0);