about summary refs log tree commit diff
path: root/third_party/abseil_cpp/absl/base/internal/spinlock_linux.inc
diff options
context:
space:
mode:
Diffstat (limited to 'third_party/abseil_cpp/absl/base/internal/spinlock_linux.inc')
-rw-r--r--third_party/abseil_cpp/absl/base/internal/spinlock_linux.inc74
1 files changed, 0 insertions, 74 deletions
diff --git a/third_party/abseil_cpp/absl/base/internal/spinlock_linux.inc b/third_party/abseil_cpp/absl/base/internal/spinlock_linux.inc
deleted file mode 100644
index e31c6ed477c0..000000000000
--- a/third_party/abseil_cpp/absl/base/internal/spinlock_linux.inc
+++ /dev/null
@@ -1,74 +0,0 @@
-// Copyright 2018 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.
-//
-// This file is a Linux-specific part of spinlock_wait.cc
-
-#include <linux/futex.h>
-#include <sys/syscall.h>
-#include <unistd.h>
-
-#include <atomic>
-#include <climits>
-#include <cstdint>
-#include <ctime>
-
-#include "absl/base/attributes.h"
-#include "absl/base/internal/errno_saver.h"
-
-// The SpinLock lockword is `std::atomic<uint32_t>`. Here we assert that
-// `std::atomic<uint32_t>` is bitwise equivalent of the `int` expected
-// by SYS_futex. We also assume that reads/writes done to the lockword
-// by SYS_futex have rational semantics with regard to the
-// std::atomic<> API. C++ provides no guarantees of these assumptions,
-// but they are believed to hold in practice.
-static_assert(sizeof(std::atomic<uint32_t>) == sizeof(int),
-              "SpinLock lockword has the wrong size for a futex");
-
-// Some Android headers are missing these definitions even though they
-// support these futex operations.
-#ifdef __BIONIC__
-#ifndef SYS_futex
-#define SYS_futex __NR_futex
-#endif
-#ifndef FUTEX_PRIVATE_FLAG
-#define FUTEX_PRIVATE_FLAG 128
-#endif
-#endif
-
-#if defined(__NR_futex_time64) && !defined(SYS_futex_time64)
-#define SYS_futex_time64 __NR_futex_time64
-#endif
-
-#if defined(SYS_futex_time64) && !defined(SYS_futex)
-#define SYS_futex SYS_futex_time64
-#endif
-
-extern "C" {
-
-ABSL_ATTRIBUTE_WEAK void AbslInternalSpinLockDelay(
-    std::atomic<uint32_t> *w, uint32_t value, int loop,
-    absl::base_internal::SchedulingMode) {
-  absl::base_internal::ErrnoSaver errno_saver;
-  struct timespec tm;
-  tm.tv_sec = 0;
-  tm.tv_nsec = absl::base_internal::SpinLockSuggestedDelayNS(loop);
-  syscall(SYS_futex, w, FUTEX_WAIT | FUTEX_PRIVATE_FLAG, value, &tm);
-}
-
-ABSL_ATTRIBUTE_WEAK void AbslInternalSpinLockWake(std::atomic<uint32_t> *w,
-                                                  bool all) {
-  syscall(SYS_futex, w, FUTEX_WAKE | FUTEX_PRIVATE_FLAG, all ? INT_MAX : 1, 0);
-}
-
-}  // extern "C"