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, 211 deletions

diff --git a/third_party/abseil_cpp/absl/base/internal/periodic_sampler.h b/third_party/abseil_cpp/absl/base/internal/periodic_sampler.h
deleted file mode 100644
index f8a86796b117..000000000000
--- a/third_party/abseil_cpp/absl/base/internal/periodic_sampler.h
+++ /dev/null
@@ -1,211 +0,0 @@
-// Copyright 2019 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.
-
-#ifndef ABSL_BASE_INTERNAL_PERIODIC_SAMPLER_H_
-#define ABSL_BASE_INTERNAL_PERIODIC_SAMPLER_H_
-
-#include <stdint.h>
-
-#include <atomic>
-
-#include "absl/base/internal/exponential_biased.h"
-#include "absl/base/optimization.h"
-
-namespace absl {
-ABSL_NAMESPACE_BEGIN
-namespace base_internal {
-
-// PeriodicSamplerBase provides the basic period sampler implementation.
-//
-// This is the base class for the templated PeriodicSampler class, which holds
-// a global std::atomic value identified by a user defined tag, such that
-// each specific PeriodSampler implementation holds its own global period.
-//
-// PeriodicSamplerBase is thread-compatible except where stated otherwise.
-class PeriodicSamplerBase {
- public:
-  // PeriodicSamplerBase is trivial / copyable / movable / destructible.
-  PeriodicSamplerBase() = default;
-  PeriodicSamplerBase(PeriodicSamplerBase&&) = default;
-  PeriodicSamplerBase(const PeriodicSamplerBase&) = default;
-
-  // Returns true roughly once every `period` calls. This is established by a
-  // randomly picked `stride` that is counted down on each call to `Sample`.
-  // This stride is picked such that the probability of `Sample()` returning
-  // true is 1 in `period`.
-  inline bool Sample() noexcept;
-
-  // The below methods are intended for optimized use cases where the
-  // size of the inlined fast path code is highly important. Applications
-  // should use the `Sample()` method unless they have proof that their
-  // specific use case requires the optimizations offered by these methods.
-  //
-  // An example of such a use case is SwissTable sampling. All sampling checks
-  // are in inlined SwissTable methods, and the number of call sites is huge.
-  // In this case, the inlined code size added to each translation unit calling
-  // SwissTable methods is non-trivial.
-  //
-  // The `SubtleMaybeSample()` function spuriously returns true even if the
-  // function should not be sampled, applications MUST match each call to
-  // 'SubtleMaybeSample()' returning true with a `SubtleConfirmSample()` call,
-  // and use the result of the latter as the sampling decision.
-  // In other words: the code should logically be equivalent to:
-  //
-  //    if (SubtleMaybeSample() && SubtleConfirmSample()) {
-  //      // Sample this call
-  //    }
-  //
-  // In the 'inline-size' optimized case, the `SubtleConfirmSample()` call can
-  // be placed out of line, for example, the typical use case looks as follows:
-  //
-  //   // --- frobber.h -----------
-  //   void FrobberSampled();
-  //
-  //   inline void FrobberImpl() {
-  //     // ...
-  //   }
-  //
-  //   inline void Frobber() {
-  //     if (ABSL_PREDICT_FALSE(sampler.SubtleMaybeSample())) {
-  //       FrobberSampled();
-  //     } else {
-  //       FrobberImpl();
-  //     }
-  //   }
-  //
-  //   // --- frobber.cc -----------
-  //   void FrobberSampled() {
-  //     if (!sampler.SubtleConfirmSample())) {
-  //       // Spurious false positive
-  //       FrobberImpl();
-  //       return;
-  //     }
-  //
-  //     // Sampled execution
-  //     // ...
-  //   }
-  inline bool SubtleMaybeSample() noexcept;
-  bool SubtleConfirmSample() noexcept;
-
- protected:
-  // We explicitly don't use a virtual destructor as this class is never
-  // virtually destroyed, and it keeps the class trivial, which avoids TLS
-  // prologue and epilogue code for our TLS instances.
-  ~PeriodicSamplerBase() = default;
-
-  // Returns the next stride for our sampler.
-  // This function is virtual for testing purposes only.
-  virtual int64_t GetExponentialBiased(int period) noexcept;
-
- private:
-  // Returns the current period of this sampler. Thread-safe.
-  virtual int period() const noexcept = 0;
-
-  // Keep and decrement stride_ as an unsigned integer, but compare the value
-  // to zero casted as a signed int. clang and msvc do not create optimum code
-  // if we use signed for the combined decrement and sign comparison.
-  //
-  // Below 3 alternative options, all compiles generate the best code
-  // using the unsigned increment <---> signed int comparison option.
-  //
-  // Option 1:
-  //   int64_t stride_;
-  //   if (ABSL_PREDICT_TRUE(++stride_ < 0)) { ... }
-  //
-  //   GCC   x64 (OK) : https://gcc.godbolt.org/z/R5MzzA
-  //   GCC   ppc (OK) : https://gcc.godbolt.org/z/z7NZAt
-  //   Clang x64 (BAD): https://gcc.godbolt.org/z/t4gPsd
-  //   ICC   x64 (OK) : https://gcc.godbolt.org/z/rE6s8W
-  //   MSVC  x64 (OK) : https://gcc.godbolt.org/z/ARMXqS
-  //
-  // Option 2:
-  //   int64_t stride_ = 0;
-  //   if (ABSL_PREDICT_TRUE(--stride_ >= 0)) { ... }
-  //
-  //   GCC   x64 (OK) : https://gcc.godbolt.org/z/jSQxYK
-  //   GCC   ppc (OK) : https://gcc.godbolt.org/z/VJdYaA
-  //   Clang x64 (BAD): https://gcc.godbolt.org/z/Xm4NjX
-  //   ICC   x64 (OK) : https://gcc.godbolt.org/z/4snaFd
-  //   MSVC  x64 (BAD): https://gcc.godbolt.org/z/BgnEKE
-  //
-  // Option 3:
-  //   uint64_t stride_;
-  //   if (ABSL_PREDICT_TRUE(static_cast<int64_t>(++stride_) < 0)) { ... }
-  //
-  //   GCC   x64 (OK) : https://gcc.godbolt.org/z/bFbfPy
-  //   GCC   ppc (OK) : https://gcc.godbolt.org/z/S9KkUE
-  //   Clang x64 (OK) : https://gcc.godbolt.org/z/UYzRb4
-  //   ICC   x64 (OK) : https://gcc.godbolt.org/z/ptTNfD
-  //   MSVC  x64 (OK) : https://gcc.godbolt.org/z/76j4-5
-  uint64_t stride_ = 0;
-  ExponentialBiased rng_;
-};
-
-inline bool PeriodicSamplerBase::SubtleMaybeSample() noexcept {
-  // See comments on `stride_` for the unsigned increment / signed compare.
-  if (ABSL_PREDICT_TRUE(static_cast<int64_t>(++stride_) < 0)) {
-    return false;
-  }
-  return true;
-}
-
-inline bool PeriodicSamplerBase::Sample() noexcept {
-  return ABSL_PREDICT_FALSE(SubtleMaybeSample()) ? SubtleConfirmSample()
-                                                 : false;
-}
-
-// PeriodicSampler is a concreted periodic sampler implementation.
-// The user provided Tag identifies the implementation, and is required to
-// isolate the global state of this instance from other instances.
-//
-// Typical use case:
-//
-//   struct HashTablezTag {};
-//   thread_local PeriodicSampler sampler;
-//
-//   void HashTableSamplingLogic(...) {
-//     if (sampler.Sample()) {
-//       HashTableSlowSamplePath(...);
-//     }
-//   }
-//
-template <typename Tag, int default_period = 0>
-class PeriodicSampler final : public PeriodicSamplerBase {
- public:
-  ~PeriodicSampler() = default;
-
-  int period() const noexcept final {
-    return period_.load(std::memory_order_relaxed);
-  }
-
-  // Sets the global period for this sampler. Thread-safe.
-  // Setting a period of 0 disables the sampler, i.e., every call to Sample()
-  // will return false. Setting a period of 1 puts the sampler in 'always on'
-  // mode, i.e., every call to Sample() returns true.
-  static void SetGlobalPeriod(int period) {
-    period_.store(period, std::memory_order_relaxed);
-  }
-
- private:
-  static std::atomic<int> period_;
-};
-
-template <typename Tag, int default_period>
-std::atomic<int> PeriodicSampler<Tag, default_period>::period_(default_period);
-
-}  // namespace base_internal
-ABSL_NAMESPACE_END
-}  // namespace absl
-
-#endif  // ABSL_BASE_INTERNAL_PERIODIC_SAMPLER_H_