chore(3p/abseil_cpp): unvendor abseil_cpp r/3786

we weren't actually using these sources anymore, okay?

Change-Id: If701571d9716de308d3512e1eb22c35db0877a66
Reviewed-on: https://cl.tvl.fyi/c/depot/+/5248
Tested-by: BuildkiteCI
Reviewed-by: grfn <grfn@gws.fyi>
Autosubmit: tazjin <tazjin@tvl.su>

1 files changed, 0 insertions, 220 deletions

diff --git a/third_party/abseil_cpp/absl/base/internal/spinlock.cc b/third_party/abseil_cpp/absl/base/internal/spinlock.cc
deleted file mode 100644
index a7d44f3eb091..000000000000
--- a/third_party/abseil_cpp/absl/base/internal/spinlock.cc
+++ /dev/null
@@ -1,220 +0,0 @@
-// Copyright 2017 The Abseil Authors.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//      https://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-#include "absl/base/internal/spinlock.h"
-
-#include <algorithm>
-#include <atomic>
-#include <limits>
-
-#include "absl/base/attributes.h"
-#include "absl/base/internal/atomic_hook.h"
-#include "absl/base/internal/cycleclock.h"
-#include "absl/base/internal/spinlock_wait.h"
-#include "absl/base/internal/sysinfo.h" /* For NumCPUs() */
-#include "absl/base/call_once.h"
-
-// Description of lock-word:
-//  31..00: [............................3][2][1][0]
-//
-//     [0]: kSpinLockHeld
-//     [1]: kSpinLockCooperative
-//     [2]: kSpinLockDisabledScheduling
-// [31..3]: ONLY kSpinLockSleeper OR
-//          Wait time in cycles >> PROFILE_TIMESTAMP_SHIFT
-//
-// Detailed descriptions:
-//
-// Bit [0]: The lock is considered held iff kSpinLockHeld is set.
-//
-// Bit [1]: Eligible waiters (e.g. Fibers) may co-operatively reschedule when
-//          contended iff kSpinLockCooperative is set.
-//
-// Bit [2]: This bit is exclusive from bit [1].  It is used only by a
-//          non-cooperative lock.  When set, indicates that scheduling was
-//          successfully disabled when the lock was acquired.  May be unset,
-//          even if non-cooperative, if a ThreadIdentity did not yet exist at
-//          time of acquisition.
-//
-// Bit [3]: If this is the only upper bit ([31..3]) set then this lock was
-//          acquired without contention, however, at least one waiter exists.
-//
-//          Otherwise, bits [31..3] represent the time spent by the current lock
-//          holder to acquire the lock.  There may be outstanding waiter(s).
-
-namespace absl {
-ABSL_NAMESPACE_BEGIN
-namespace base_internal {
-
-ABSL_INTERNAL_ATOMIC_HOOK_ATTRIBUTES static base_internal::AtomicHook<void (*)(
-    const void *lock, int64_t wait_cycles)>
-    submit_profile_data;
-
-void RegisterSpinLockProfiler(void (*fn)(const void *contendedlock,
-                                         int64_t wait_cycles)) {
-  submit_profile_data.Store(fn);
-}
-
-// Static member variable definitions.
-constexpr uint32_t SpinLock::kSpinLockHeld;
-constexpr uint32_t SpinLock::kSpinLockCooperative;
-constexpr uint32_t SpinLock::kSpinLockDisabledScheduling;
-constexpr uint32_t SpinLock::kSpinLockSleeper;
-constexpr uint32_t SpinLock::kWaitTimeMask;
-
-// Uncommon constructors.
-SpinLock::SpinLock(base_internal::SchedulingMode mode)
-    : lockword_(IsCooperative(mode) ? kSpinLockCooperative : 0) {
-  ABSL_TSAN_MUTEX_CREATE(this, __tsan_mutex_not_static);
-}
-
-// 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.
-uint32_t SpinLock::SpinLoop() {
-  // We are already in the slow path of SpinLock, initialize the
-  // adaptive_spin_count here.
-  ABSL_CONST_INIT static absl::once_flag init_adaptive_spin_count;
-  ABSL_CONST_INIT static int adaptive_spin_count = 0;
-  base_internal::LowLevelCallOnce(&init_adaptive_spin_count, []() {
-    adaptive_spin_count = base_internal::NumCPUs() > 1 ? 1000 : 1;
-  });
-
-  int c = adaptive_spin_count;
-  uint32_t lock_value;
-  do {
-    lock_value = lockword_.load(std::memory_order_relaxed);
-  } while ((lock_value & kSpinLockHeld) != 0 && --c > 0);
-  return lock_value;
-}
-
-void SpinLock::SlowLock() {
-  uint32_t lock_value = SpinLoop();
-  lock_value = TryLockInternal(lock_value, 0);
-  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
-  // obtains the lock.
-  int64_t wait_start_time = CycleClock::Now();
-  uint32_t wait_cycles = 0;
-  int lock_wait_call_count = 0;
-  while ((lock_value & kSpinLockHeld) != 0) {
-    // If the lock is currently held, but not marked as having a sleeper, mark
-    // it as having a sleeper.
-    if ((lock_value & kWaitTimeMask) == 0) {
-      // Here, just "mark" that the thread is going to sleep.  Don't store the
-      // lock wait time in the lock as that will cause the current lock
-      // owner to think it experienced contention.
-      if (lockword_.compare_exchange_strong(
-              lock_value, lock_value | kSpinLockSleeper,
-              std::memory_order_relaxed, std::memory_order_relaxed)) {
-        // Successfully transitioned to kSpinLockSleeper.  Pass
-        // kSpinLockSleeper to the SpinLockWait routine to properly indicate
-        // the last lock_value observed.
-        lock_value |= kSpinLockSleeper;
-      } else if ((lock_value & kSpinLockHeld) == 0) {
-        // Lock is free again, so try and acquire it before sleeping.  The
-        // new lock state will be the number of cycles this thread waited if
-        // this thread obtains the lock.
-        lock_value = TryLockInternal(lock_value, wait_cycles);
-        continue;   // Skip the delay at the end of the loop.
-      }
-    }
-
-    // SpinLockDelay() calls into fiber scheduler, we need to see
-    // synchronization there to avoid false positives.
-    ABSL_TSAN_MUTEX_PRE_DIVERT(this, 0);
-    // Wait for an OS specific delay.
-    base_internal::SpinLockDelay(&lockword_, lock_value, ++lock_wait_call_count,
-                                 scheduling_mode);
-    ABSL_TSAN_MUTEX_POST_DIVERT(this, 0);
-    // Spin again after returning from the wait routine to give this thread
-    // some chance of obtaining the lock.
-    lock_value = SpinLoop();
-    wait_cycles = EncodeWaitCycles(wait_start_time, CycleClock::Now());
-    lock_value = TryLockInternal(lock_value, wait_cycles);
-  }
-}
-
-void SpinLock::SlowUnlock(uint32_t lock_value) {
-  base_internal::SpinLockWake(&lockword_,
-                              false);  // wake waiter if necessary
-
-  // If our acquisition was contended, collect contentionz profile info.  We
-  // reserve a unitary wait time to represent that a waiter exists without our
-  // own acquisition having been contended.
-  if ((lock_value & kWaitTimeMask) != kSpinLockSleeper) {
-    const uint64_t wait_cycles = DecodeWaitCycles(lock_value);
-    ABSL_TSAN_MUTEX_PRE_DIVERT(this, 0);
-    submit_profile_data(this, wait_cycles);
-    ABSL_TSAN_MUTEX_POST_DIVERT(this, 0);
-  }
-}
-
-// We use the upper 29 bits of the lock word to store the time spent waiting to
-// acquire this lock.  This is reported by contentionz profiling.  Since the
-// lower bits of the cycle counter wrap very quickly on high-frequency
-// processors we divide to reduce the granularity to 2^kProfileTimestampShift
-// sized units.  On a 4Ghz machine this will lose track of wait times greater
-// than (2^29/4 Ghz)*128 =~ 17.2 seconds.  Such waits should be extremely rare.
-static constexpr int kProfileTimestampShift = 7;
-
-// We currently reserve the lower 3 bits.
-static constexpr int kLockwordReservedShift = 3;
-
-uint32_t SpinLock::EncodeWaitCycles(int64_t wait_start_time,
-                                    int64_t wait_end_time) {
-  static const int64_t kMaxWaitTime =
-      std::numeric_limits<uint32_t>::max() >> kLockwordReservedShift;
-  int64_t scaled_wait_time =
-      (wait_end_time - wait_start_time) >> kProfileTimestampShift;
-
-  // Return a representation of the time spent waiting that can be stored in
-  // the lock word's upper bits.
-  uint32_t clamped = static_cast<uint32_t>(
-      std::min(scaled_wait_time, kMaxWaitTime) << kLockwordReservedShift);
-
-  if (clamped == 0) {
-    return kSpinLockSleeper;  // Just wake waiters, but don't record contention.
-  }
-  // Bump up value if necessary to avoid returning kSpinLockSleeper.
-  const uint32_t kMinWaitTime =
-      kSpinLockSleeper + (1 << kLockwordReservedShift);
-  if (clamped == kSpinLockSleeper) {
-    return kMinWaitTime;
-  }
-  return clamped;
-}
-
-uint64_t SpinLock::DecodeWaitCycles(uint32_t lock_value) {
-  // Cast to uint32_t first to ensure bits [63:32] are cleared.
-  const uint64_t scaled_wait_time =
-      static_cast<uint32_t>(lock_value & kWaitTimeMask);
-  return scaled_wait_time << (kProfileTimestampShift - kLockwordReservedShift);
-}
-
-}  // namespace base_internal
-ABSL_NAMESPACE_END
-}  // namespace absl